Toxic substances formed in or elaborated by bacteria; they are usually proteins with high molecular weight and antigenicity; some are used as antibiotics and some to skin test for the presence of or susceptibility to certain diseases.
An ENTEROTOXIN from VIBRIO CHOLERAE. It consists of two major protomers, the heavy (H) or A subunit and the B protomer which consists of 5 light (L) or B subunits. The catalytic A subunit is proteolytically cleaved into fragments A1 and A2. The A1 fragment is a MONO(ADP-RIBOSE) TRANSFERASE. The B protomer binds cholera toxin to intestinal epithelial cells, and facilitates the uptake of the A1 fragment. The A1 catalyzed transfer of ADP-RIBOSE to the alpha subunits of heterotrimeric G PROTEINS activates the production of CYCLIC AMP. Increased levels of cyclic AMP are thought to modulate release of fluid and electrolytes from intestinal crypt cells.
Enzymes that transfer the ADP-RIBOSE group of NAD or NADP to proteins or other small molecules. Transfer of ADP-ribose to water (i.e., hydrolysis) is catalyzed by the NADASES. The mono(ADP-ribose)transferases transfer a single ADP-ribose. POLY(ADP-RIBOSE) POLYMERASES transfer multiple units of ADP-ribose to protein targets, building POLY ADENOSINE DIPHOSPHATE RIBOSE in linear or branched chains.
Exotoxins produced by certain strains of streptococci, particularly those of group A (STREPTOCOCCUS PYOGENES), that cause HEMOLYSIS.
Substances that are toxic to cells; they may be involved in immunity or may be contained in venoms. These are distinguished from CYTOSTATIC AGENTS in degree of effect. Some of them are used as CYTOTOXIC ANTIBIOTICS. The mechanism of action of many of these are as ALKYLATING AGENTS or MITOSIS MODULATORS.
A potent mycotoxin produced in feedstuffs by several species of the genus FUSARIUM. It elicits a severe inflammatory reaction in animals and has teratogenic effects.
Substances that are toxic to the intestinal tract causing vomiting, diarrhea, etc.; most common enterotoxins are produced by bacteria.
Proteins from BACTERIA and FUNGI that are soluble enough to be secreted to target ERYTHROCYTES and insert into the membrane to form beta-barrel pores. Biosynthesis may be regulated by HEMOLYSIN FACTORS.
Specific, characterizable, poisonous chemicals, often PROTEINS, with specific biological properties, including immunogenicity, produced by microbes, higher plants (PLANTS, TOXIC), or ANIMALS.
Toxins produced, especially by bacterial or fungal cells, and released into the culture medium or environment.
Proteins found in any species of bacterium.
Protein synthesized by CLOSTRIDIUM TETANI as a single chain of ~150 kDa with 35% sequence identity to BOTULINUM TOXIN that is cleaved to a light and a heavy chain that are linked by a single disulfide bond. Tetanolysin is the hemolytic and tetanospasmin is the neurotoxic principle. The toxin causes disruption of the inhibitory mechanisms of the CNS, thus permitting uncontrolled nervous activity, leading to fatal CONVULSIONS.
An ester formed between the aldehydic carbon of RIBOSE and the terminal phosphate of ADENOSINE DIPHOSPHATE. It is produced by the hydrolysis of nicotinamide-adenine dinucleotide (NAD) by a variety of enzymes, some of which transfer an ADP-ribosyl group to target proteins.
An ADP-ribosylating polypeptide produced by CORYNEBACTERIUM DIPHTHERIAE that causes the signs and symptoms of DIPHTHERIA. It can be broken into two unequal domains: the smaller, catalytic A domain is the lethal moiety and contains MONO(ADP-RIBOSE) TRANSFERASES which transfers ADP RIBOSE to PEPTIDE ELONGATION FACTOR 2 thereby inhibiting protein synthesis; and the larger B domain that is needed for entry into cells.
Antisera from immunized animals that is purified and used as a passive immunizing agent against specific BACTERIAL TOXINS.
One of the virulence factors produced by virulent BORDETELLA organisms. It is a bifunctional protein with both ADENYLYL CYCLASES and hemolysin components.
Proteins obtained from ESCHERICHIA COLI.
A serotype of botulinum toxins that has specificity for cleavage of SYNAPTOSOMAL-ASSOCIATED PROTEIN 25.
Toxic or poisonous substances elaborated by marine flora or fauna. They include also specific, characterized poisons or toxins for which there is no more specific heading, like those from poisonous FISHES.
Toxic proteins produced from the species CLOSTRIDIUM BOTULINUM. The toxins are synthesized as a single peptide chain which is processed into a mature protein consisting of a heavy chain and light chain joined via a disulfide bond. The botulinum toxin light chain is a zinc-dependent protease which is released from the heavy chain upon ENDOCYTOSIS into PRESYNAPTIC NERVE ENDINGS. Once inside the cell the botulinum toxin light chain cleaves specific SNARE proteins which are essential for secretion of ACETYLCHOLINE by SYNAPTIC VESICLES. This inhibition of acetylcholine release results in muscular PARALYSIS.
Those components of an organism that determine its capacity to cause disease but are not required for its viability per se. Two classes have been characterized: TOXINS, BIOLOGICAL and surface adhesion molecules that effect the ability of the microorganism to invade and colonize a host. (From Davis et al., Microbiology, 4th ed. p486)
A species of bacteria that causes ANTHRAX in humans and animals.
A large family of MONOMERIC GTP-BINDING PROTEINS that are involved in regulation of actin organization, gene expression and cell cycle progression. This enzyme was formerly listed as EC
A class of toxins that inhibit protein synthesis by blocking the interaction of ribosomal RNA; (RNA, RIBOSOMAL) with PEPTIDE ELONGATION FACTORS. They include SHIGA TOXIN which is produced by SHIGELLA DYSENTERIAE and a variety of shiga-like toxins that are produced by pathologic strains of ESCHERICHIA COLI such as ESCHERICHIA COLI O157.
Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.
A proprotein convertase with specificity for the proproteins of PROALBUMIN; COMPLEMENT 3C; and VON WILLEBRAND FACTOR. It has specificity for cleavage near paired ARGININE residues that are separated by two amino acids.
Bacteriocins elaborated by strains of Escherichia coli and related species. They are proteins or protein-lipopolysaccharide complexes lethal to other strains of the same species.
The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.
A toxin produced by certain pathogenic strains of ESCHERICHIA COLI such as ESCHERICHIA COLI O157. It shares 50-60% homology with SHIGA TOXIN and SHIGA TOXIN 1.
One of the virulence factors produced by BORDETELLA PERTUSSIS. It is a multimeric protein composed of five subunits S1 - S5. S1 contains mono ADPribose transferase activity.
A toxin produced by certain pathogenic strains of ESCHERICHIA COLI such as ESCHERICHIA COLI O157. It is closely related to SHIGA TOXIN produced by SHIGELLA DYSENTERIAE.
Proteins secreted from an organism which form membrane-spanning pores in target cells to destroy them. This is in contrast to PORINS and MEMBRANE TRANSPORT PROTEINS that function within the synthesizing organism and COMPLEMENT immune proteins. These pore forming cytotoxic proteins are a form of primitive cellular defense which are also found in human LYMPHOCYTES.
Microbial antigens that have in common an extremely potent activating effect on T-cells that bear a specific variable region. Superantigens cross-link the variable region with class II MHC proteins regardless of the peptide binding in the T-cell receptor's pocket. The result is a transient expansion and subsequent death and anergy of the T-cells with the appropriate variable regions.
Semisynthetic conjugates of various toxic molecules, including RADIOACTIVE ISOTOPES and bacterial or plant toxins, with specific immune substances such as IMMUNOGLOBULINS; MONOCLONAL ANTIBODIES; and ANTIGENS. The antitumor or antiviral immune substance carries the toxin to the tumor or infected cell where the toxin exerts its poisonous effect.
The most common etiologic agent of GAS GANGRENE. It is differentiable into several distinct types based on the distribution of twelve different toxins.
A species of gram-negative, facultatively anaerobic, rod-shaped bacteria (GRAM-NEGATIVE FACULTATIVELY ANAEROBIC RODS) commonly found in the lower part of the intestine of warm-blooded animals. It is usually nonpathogenic, but some strains are known to produce DIARRHEA and pyogenic infections. Pathogenic strains (virotypes) are classified by their specific pathogenic mechanisms such as toxins (ENTEROTOXIGENIC ESCHERICHIA COLI), etc.
A set of BACTERIAL ADHESINS and TOXINS, BIOLOGICAL produced by BORDETELLA organisms that determine the pathogenesis of BORDETELLA INFECTIONS, such as WHOOPING COUGH. They include filamentous hemagglutinin; FIMBRIAE PROTEINS; pertactin; PERTUSSIS TOXIN; ADENYLATE CYCLASE TOXIN; dermonecrotic toxin; tracheal cytotoxin; Bordetella LIPOPOLYSACCHARIDES; and tracheal colonization factor.
A toxin produced by SHIGELLA DYSENTERIAE. It is the prototype of class of toxins that inhibit protein synthesis by blocking the interaction of ribosomal RNA; (RNA, RIBOSOMAL) with PEPTIDE ELONGATION FACTORS.
The lipid- and protein-containing, selectively permeable membrane that surrounds the cytoplasm in prokaryotic and eukaryotic cells.
Models used experimentally or theoretically to study molecular shape, electronic properties, or interactions; includes analogous molecules, computer-generated graphics, and mechanical structures.
The destruction of ERYTHROCYTES by many different causal agents such as antibodies, bacteria, chemicals, temperature, and changes in tonicity.
The process in which substances, either endogenous or exogenous, bind to proteins, peptides, enzymes, protein precursors, or allied compounds. Specific protein-binding measures are often used as assays in diagnostic assessments.
Substances elaborated by bacteria that have antigenic activity.
Established cell cultures that have the potential to propagate indefinitely.
The level of protein structure in which combinations of secondary protein structures (alpha helices, beta sheets, loop regions, and motifs) pack together to form folded shapes called domains. Disulfide bridges between cysteines in two different parts of the polypeptide chain along with other interactions between the chains play a role in the formation and stabilization of tertiary structure. Small proteins usually consist of only one domain but larger proteins may contain a number of domains connected by segments of polypeptide chain which lack regular secondary structure.
Potentially pathogenic bacteria found in nasal membranes, skin, hair follicles, and perineum of warm-blooded animals. They may cause a wide range of infections and intoxications.
Regulatory proteins that act as molecular switches. They control a wide range of biological processes including: receptor signaling, intracellular signal transduction pathways, and protein synthesis. Their activity is regulated by factors that control their ability to bind to and hydrolyze GTP to GDP. EC 3.6.1.-.
A coenzyme composed of ribosylnicotinamide 5'-diphosphate coupled to adenosine 5'-phosphate by pyrophosphate linkage. It is found widely in nature and is involved in numerous enzymatic reactions in which it serves as an electron carrier by being alternately oxidized (NAD+) and reduced (NADH). (Dorland, 27th ed)
The rate dynamics in chemical or physical systems.
The degree of similarity between sequences of amino acids. This information is useful for the analyzing genetic relatedness of proteins and species.
The parts of a macromolecule that directly participate in its specific combination with another molecule.
The characteristic 3-dimensional shape of a protein, including the secondary, supersecondary (motifs), tertiary (domains) and quaternary structure of the peptide chain. PROTEIN STRUCTURE, QUATERNARY describes the conformation assumed by multimeric proteins (aggregates of more than one polypeptide chain).
The process of moving proteins from one cellular compartment (including extracellular) to another by various sorting and transport mechanisms such as gated transport, protein translocation, and vesicular transport.
The first continuously cultured human malignant CELL LINE, derived from the cervical carcinoma of Henrietta Lacks. These cells are used for VIRUS CULTIVATION and antitumor drug screening assays.
Cells propagated in vitro in special media conducive to their growth. Cultured cells are used to study developmental, morphologic, metabolic, physiologic, and genetic processes, among others.
Proteins prepared by recombinant DNA technology.
The relationship between the dose of an administered drug and the response of the organism to the drug.
Recombinant proteins produced by the GENETIC TRANSLATION of fused genes formed by the combination of NUCLEIC ACID REGULATORY SEQUENCES of one or more genes with the protein coding sequences of one or more genes.
A RHO GTP-BINDING PROTEIN involved in regulating signal transduction pathways that control assembly of focal adhesions and actin stress fibers. This enzyme was formerly listed as EC
The relationship between the chemical structure of a compound and its biological or pharmacological activity. Compounds are often classed together because they have structural characteristics in common including shape, size, stereochemical arrangement, and distribution of functional groups.
Filamentous proteins that are the main constituent of the thin filaments of muscle fibers. The filaments (known also as filamentous or F-actin) can be dissociated into their globular subunits; each subunit is composed of a single polypeptide 375 amino acids long. This is known as globular or G-actin. In conjunction with MYOSINS, actin is responsible for the contraction and relaxation of muscle.
One of the three domains of life (the others being Eukarya and ARCHAEA), also called Eubacteria. They are unicellular prokaryotic microorganisms which generally possess rigid cell walls, multiply by cell division, and exhibit three principal forms: round or coccal, rodlike or bacillary, and spiral or spirochetal. Bacteria can be classified by their response to OXYGEN: aerobic, anaerobic, or facultatively anaerobic; by the mode by which they obtain their energy: chemotrophy (via chemical reaction) or PHOTOTROPHY (via light reaction); for chemotrophs by their source of chemical energy: CHEMOLITHOTROPHY (from inorganic compounds) or chemoorganotrophy (from organic compounds); and by their source for CARBON; NITROGEN; etc.; HETEROTROPHY (from organic sources) or AUTOTROPHY (from CARBON DIOXIDE). They can also be classified by whether or not they stain (based on the structure of their CELL WALLS) with CRYSTAL VIOLET dye: gram-negative or gram-positive.
A subfamily in the family MURIDAE, comprising the hamsters. Four of the more common genera are Cricetus, CRICETULUS; MESOCRICETUS; and PHODOPUS.
Venoms from animals of the order Scorpionida of the class Arachnida. They contain neuro- and hemotoxins, enzymes, and various other factors that may release acetylcholine and catecholamines from nerve endings. Of the several protein toxins that have been characterized, most are immunogenic.
Cell surface proteins that bind signalling molecules external to the cell with high affinity and convert this extracellular event into one or more intracellular signals that alter the behavior of the target cell (From Alberts, Molecular Biology of the Cell, 2nd ed, pp693-5). Cell surface receptors, unlike enzymes, do not chemically alter their ligands.
A common inhabitant of the colon flora in human infants and sometimes in adults. It produces a toxin that causes pseudomembranous enterocolitis (ENTEROCOLITIS, PSEUDOMEMBRANOUS) in patients receiving antibiotic therapy.
A species of CERCOPITHECUS containing three subspecies: C. tantalus, C. pygerythrus, and C. sabeus. They are found in the forests and savannah of Africa. The African green monkey (C. pygerythrus) is the natural host of SIMIAN IMMUNODEFICIENCY VIRUS and is used in AIDS research.
Cellular uptake of extracellular materials within membrane-limited vacuoles or microvesicles. ENDOSOMES play a central role in endocytosis.
Toxic compounds produced by FUNGI.
A characteristic feature of enzyme activity in relation to the kind of substrate on which the enzyme or catalytic molecule reacts.
The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.
CELL LINE derived from the ovary of the Chinese hamster, Cricetulus griseus (CRICETULUS). The species is a favorite for cytogenetic studies because of its small chromosome number. The cell line has provided model systems for the study of genetic alterations in cultured mammalian cells.
Layers of lipid molecules which are two molecules thick. Bilayer systems are frequently studied as models of biological membranes.
An adenine nucleotide containing one phosphate group which is esterified to both the 3'- and 5'-positions of the sugar moiety. It is a second messenger and a key intracellular regulator, functioning as a mediator of activity for a number of hormones, including epinephrine, glucagon, and ACTH.
The species Oryctolagus cuniculus, in the family Leporidae, order LAGOMORPHA. Rabbits are born in burrows, furless, and with eyes and ears closed. In contrast with HARES, rabbits have 22 chromosome pairs.
The intracellular transfer of information (biological activation/inhibition) through a signal pathway. In each signal transduction system, an activation/inhibition signal from a biologically active molecule (hormone, neurotransmitter) is mediated via the coupling of a receptor/enzyme to a second messenger system or to an ion channel. Signal transduction plays an important role in activating cellular functions, cell differentiation, and cell proliferation. Examples of signal transduction systems are the GAMMA-AMINOBUTYRIC ACID-postsynaptic receptor-calcium ion channel system, the receptor-mediated T-cell activation pathway, and the receptor-mediated activation of phospholipases. Those coupled to membrane depolarization or intracellular release of calcium include the receptor-mediated activation of cytotoxic functions in granulocytes and the synaptic potentiation of protein kinase activation. Some signal transduction pathways may be part of larger signal transduction pathways; for example, protein kinase activation is part of the platelet activation signal pathway.
Artificial, single or multilaminar vesicles (made from lecithins or other lipids) that are used for the delivery of a variety of biological molecules or molecular complexes to cells, for example, drug delivery and gene transfer. They are also used to study membranes and membrane proteins.
The arrangement of two or more amino acid or base sequences from an organism or organisms in such a way as to align areas of the sequences sharing common properties. The degree of relatedness or homology between the sequences is predicted computationally or statistically based on weights assigned to the elements aligned between the sequences. This in turn can serve as a potential indicator of the genetic relatedness between the organisms.
Members of the class of compounds composed of AMINO ACIDS joined together by peptide bonds between adjacent amino acids into linear, branched or cyclical structures. OLIGOPEPTIDES are composed of approximately 2-12 amino acids. Polypeptides are composed of approximately 13 or more amino acids. PROTEINS are linear polypeptides that are normally synthesized on RIBOSOMES.
Lipid-containing polysaccharides which are endotoxins and important group-specific antigens. They are often derived from the cell wall of gram-negative bacteria and induce immunoglobulin secretion. The lipopolysaccharide molecule consists of three parts: LIPID A, core polysaccharide, and O-specific chains (O ANTIGENS). When derived from Escherichia coli, lipopolysaccharides serve as polyclonal B-cell mitogens commonly used in laboratory immunology. (From Dorland, 28th ed)
A species of gram-negative, aerobic, rod-shaped bacteria commonly isolated from clinical specimens (wound, burn, and urinary tract infections). It is also found widely distributed in soil and water. P. aeruginosa is a major agent of nosocomial infection.
The level of protein structure in which regular hydrogen-bond interactions within contiguous stretches of polypeptide chain give rise to alpha helices, beta strands (which align to form beta sheets) or other types of coils. This is the first folding level of protein conformation.
Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.
Drugs used for their actions on skeletal muscle. Included are agents that act directly on skeletal muscle, those that alter neuromuscular transmission (NEUROMUSCULAR BLOCKING AGENTS), and drugs that act centrally as skeletal muscle relaxants (MUSCLE RELAXANTS, CENTRAL). Drugs used in the treatment of movement disorders are ANTI-DYSKINESIA AGENTS.
Proteins which are found in membranes including cellular and intracellular membranes. They consist of two types, peripheral and integral proteins. They include most membrane-associated enzymes, antigenic proteins, transport proteins, and drug, hormone, and lectin receptors.
Genetically engineered MUTAGENESIS at a specific site in the DNA molecule that introduces a base substitution, or an insertion or deletion.
Conversion of an inactive form of an enzyme to one possessing metabolic activity. It includes 1, activation by ions (activators); 2, activation by cofactors (coenzymes); and 3, conversion of an enzyme precursor (proenzyme or zymogen) to an active enzyme.
The normality of a solution with respect to HYDROGEN ions; H+. It is related to acidity measurements in most cases by pH = log 1/2[1/(H+)], where (H+) is the hydrogen ion concentration in gram equivalents per liter of solution. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)
Arthropods of the order Scorpiones, of which 1500 to 2000 species have been described. The most common live in tropical or subtropical areas. They are nocturnal and feed principally on insects and other arthropods. They are large arachnids but do not attack man spontaneously. They have a venomous sting. Their medical significance varies considerably and is dependent on their habits and venom potency rather than on their size. At most, the sting is equivalent to that of a hornet but certain species possess a highly toxic venom potentially fatal to humans. (From Dorland, 27th ed; Smith, Insects and Other Arthropods of Medical Importance, 1973, p417; Barnes, Invertebrate Zoology, 5th ed, p503)
The study of crystal structure using X-RAY DIFFRACTION techniques. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)
A protein phytotoxin from the seeds of Ricinus communis, the castor oil plant. It agglutinates cells, is proteolytic, and causes lethal inflammation and hemorrhage if taken internally.
The insertion of recombinant DNA molecules from prokaryotic and/or eukaryotic sources into a replicating vehicle, such as a plasmid or virus vector, and the introduction of the resultant hybrid molecules into recipient cells without altering the viability of those cells.
Elements of limited time intervals, contributing to particular results or situations.
Toxic substances from microorganisms, plants or animals that interfere with the functions of the nervous system. Most venoms contain neurotoxic substances. Myotoxins are included in this concept.
A species of anaerobic, gram-positive, rod-shaped bacteria in the family Clostridiaceae that produces proteins with characteristic neurotoxicity. It is the etiologic agent of BOTULISM in humans, wild fowl, HORSES; and CATTLE. Seven subtypes (sometimes called antigenic types, or strains) exist, each producing a different botulinum toxin (BOTULINUM TOXINS). The organism and its spores are widely distributed in nature.
Inbred BALB/c mice are a strain of laboratory mice that have been selectively bred to be genetically identical to each other, making them useful for scientific research and experiments due to their consistent genetic background and predictable responses to various stimuli or treatments.
A species of gram-positive bacteria which may be pathogenic for certain insects. It is used for the biological control of the Gypsy moth.
Venoms of arthropods of the order Araneida of the ARACHNIDA. The venoms usually contain several protein fractions, including ENZYMES, hemolytic, neurolytic, and other TOXINS, BIOLOGICAL.
Venoms from jellyfish; CORALS; SEA ANEMONES; etc. They contain hemo-, cardio-, dermo- , and neuro-toxic substances and probably ENZYMES. They include palytoxin, sarcophine, and anthopleurine.
One of the mechanisms by which CELL DEATH occurs (compare with NECROSIS and AUTOPHAGOCYTOSIS). Apoptosis is the mechanism responsible for the physiological deletion of cells and appears to be intrinsically programmed. It is characterized by distinctive morphologic changes in the nucleus and cytoplasm, chromatin cleavage at regularly spaced sites, and the endonucleolytic cleavage of genomic DNA; (DNA FRAGMENTATION); at internucleosomal sites. This mode of cell death serves as a balance to mitosis in regulating the size of animal tissues and in mediating pathologic processes associated with tumor growth.
Inbred C57BL mice are a strain of laboratory mice that have been produced by many generations of brother-sister matings, resulting in a high degree of genetic uniformity and homozygosity, making them widely used for biomedical research, including studies on genetics, immunology, cancer, and neuroscience.
Preparations of pathogenic organisms or their derivatives made nontoxic and intended for active immunologic prophylaxis. They include deactivated toxins. Anatoxin toxoids are distinct from anatoxins that are TROPANES found in CYANOBACTERIA.
Theoretical representations that simulate the behavior or activity of biological processes or diseases. For disease models in living animals, DISEASE MODELS, ANIMAL is available. Biological models include the use of mathematical equations, computers, and other electronic equipment.
The relatively long-lived phagocytic cell of mammalian tissues that are derived from blood MONOCYTES. Main types are PERITONEAL MACROPHAGES; ALVEOLAR MACROPHAGES; HISTIOCYTES; KUPFFER CELLS of the liver; and OSTEOCLASTS. They may further differentiate within chronic inflammatory lesions to EPITHELIOID CELLS or may fuse to form FOREIGN BODY GIANT CELLS or LANGHANS GIANT CELLS. (from The Dictionary of Cell Biology, Lackie and Dow, 3rd ed.)
The etiologic agent of CHOLERA.
The biosynthesis of PEPTIDES and PROTEINS on RIBOSOMES, directed by MESSENGER RNA, via TRANSFER RNA that is charged with standard proteinogenic AMINO ACIDS.
Protein exotoxins from Staphylococcus aureus, phage type II, which cause epidermal necrolysis. They are proteins with a molecular weight of 26,000 to 32,000. They cause a condition variously called scaled skin, Lyell or Ritter syndrome, epidermal exfoliative disease, toxic epidermal necrolysis, etc.
Protein factors released from one species of YEAST that are selectively toxic to another species of yeast.
Toxins closely associated with the living cytoplasm or cell wall of certain microorganisms, which do not readily diffuse into the culture medium, but are released upon lysis of the cells.
A species of gram-negative, aerobic bacteria that is the causative agent of WHOOPING COUGH. Its cells are minute coccobacilli that are surrounded by a slime sheath.
The order Actiniaria, in the class ANTHOZOA, comprised of large, solitary polyps. All species are carnivorous.
An acute infection caused by the spore-forming bacteria BACILLUS ANTHRACIS. It commonly affects hoofed animals such as sheep and goats. Infection in humans often involves the skin (cutaneous anthrax), the lungs (inhalation anthrax), or the gastrointestinal tract. Anthrax is not contagious and can be treated with antibiotics.
Poisoning from toxins present in bivalve mollusks that have been ingested. Four distinct types of shellfish poisoning are recognized based on the toxin involved.
An acute inflammation of the INTESTINAL MUCOSA that is characterized by the presence of pseudomembranes or plaques in the SMALL INTESTINE (pseudomembranous enteritis) and the LARGE INTESTINE (pseudomembranous colitis). It is commonly associated with antibiotic therapy and CLOSTRIDIUM DIFFICILE colonization.
Infections with bacteria of the genus CLOSTRIDIUM.
The dose amount of poisonous or toxic substance or dose of ionizing radiation required to kill 50% of the tested population.
Glycosphingolipids which contain as their polar head group a trisaccharide (galactose-galactose-glucose) moiety bound in glycosidic linkage to the hydroxyl group of ceramide. Their accumulation in tissue, due to a defect in ceramide trihexosidase, is the cause of angiokeratoma corporis diffusum (FABRY DISEASE).
Use of naturally-occuring or genetically-engineered organisms to reduce or eliminate populations of pests.
A species of gram-positive, asporogenous bacteria in which three cultural types are recognized. These types (gravis, intermedius, and mitis) were originally given in accordance with the clinical severity of the cases from which the different strains were most frequently isolated. This species is the causative agent of DIPHTHERIA.
A species of gram-negative, facultatively anaerobic, rod-shaped bacteria that is extremely pathogenic and causes severe dysentery. Infection with this organism often leads to ulceration of the intestinal epithelium.
A specific monosialoganglioside that accumulates abnormally within the nervous system due to a deficiency of GM1-b-galactosidase, resulting in GM1 gangliosidosis.
Usually 12,13-epoxytrichothecenes, produced by Fusaria, Stachybotrys, Trichoderma and other fungi, and some higher plants. They may contaminate food or feed grains, induce emesis and hemorrhage in lungs and brain, and damage bone marrow due to protein and DNA synthesis inhibition.
A genus of motile or nonmotile gram-positive bacteria of the family Clostridiaceae. Many species have been identified with some being pathogenic. They occur in water, soil, and in the intestinal tract of humans and lower animals.
Venoms from snakes of the family Elapidae, including cobras, kraits, mambas, coral, tiger, and Australian snakes. The venoms contain polypeptide toxins of various kinds, cytolytic, hemolytic, and neurotoxic factors, but fewer enzymes than viper or crotalid venoms. Many of the toxins have been characterized.
A family of extremely venomous snakes, comprising coral snakes, cobras, mambas, kraits, and sea snakes. They are widely distributed, being found in the southern United States, South America, Africa, southern Asia, Australia, and the Pacific Islands. The elapids include three subfamilies: Elapinae, Hydrophiinae, and Lauticaudinae. Like the viperids, they have venom fangs in the front part of the upper jaw. The mambas of Africa are the most dangerous of all snakes by virtue of their size, speed, and highly toxic venom. (Goin, Goin, and Zug, Introduction to Herpetology, 3d ed, p329-33)
A method of measuring the effects of a biologically active substance using an intermediate in vivo or in vitro tissue or cell model under controlled conditions. It includes virulence studies in animal fetuses in utero, mouse convulsion bioassay of insulin, quantitation of tumor-initiator systems in mouse skin, calculation of potentiating effects of a hormonal factor in an isolated strip of contracting stomach muscle, etc.
A compound that contains a reduced purine ring system but is not biosynthetically related to the purine alkaloids. It is a poison found in certain edible mollusks at certain times; elaborated by GONYAULAX and consumed by mollusks, fishes, etc. without ill effects. It is neurotoxic and causes RESPIRATORY PARALYSIS and other effects in MAMMALS, known as paralytic SHELLFISH poisoning.
Immunoglobulins produced in a response to BACTERIAL ANTIGENS.

The significance of cagA and vacA subtypes of Helicobacter pylori in the pathogenesis of inflammation and peptic ulceration. (1/8457)

AIMS: To assess the significance of cagA and vacA subtypes of Helicobacter pylori in relation to inflammation and density of bacterial colonisation in vivo within a dyspeptic UK population. METHODS: Dyspeptic patients who were Helicobacter pylori positive had antral samples taken for histology and culture. Gastroduodenal pathology was noted. The grade of bacterial density and inflammation was assessed using the Sydney system. Bacterial DNA was extracted and the vacA alleles and the cagA/gene typed using PCR. RESULTS: 120 patients were studied. There was high rate of cagA positive strains in this population. Bacterial density did not correlate with the presence of peptic ulceration. There was a significant association between cagA positive strains and increased inflammation and bacterial density. The vacA s1 type independently correlated with extensive chronic inflammation but there was no association with bacterial density. The vacA m type did not correlate with extent of inflammation or bacterial density. CONCLUSIONS: The results suggest that cagA is important in the pathogenesis of inflammation and peptic ulceration. These findings are in keeping with the hypothesis that cagA acts as a marker for a cag pathogenicity island which encodes several genes involved in inflammation. The vacA s1 allele correlates with inflammation independently of cagA, possibly through its enhanced ability to produce the vacuolating cytotoxin.  (+info)

Synergistic activation of JNK/SAPK by interleukin-1 and platelet-derived growth factor is independent of Rac and Cdc42. (2/8457)

The c-Jun N-terminal kinases (JNKs) are activated strongly by inflammatory cytokines and environmental stresses, but only weakly by growth factors. Here we show that platelet-derived growth factor (PDGF) strongly potentiates activation of JNK by interleukin 1 (IL-1) in human fibroblasts and a pig aortic endothelial (PAE) cell line. This synergistic activation of JNK by IL-1 and PDGF was unaffected by bacterial toxins that inactivate Rho proteins and Ras. Since Rho proteins have been implicated in JNK activation, their possible involvement was investigated further using stably expressed, inducible N17 or V12 mutants in PAE cell lines. N17 Rac non-selectively reduced JNK activity by 30% in resting or stimulated cells (IL-1 alone, or with PDGF). N17 Cdc42 had no effect. V12 Rac weakly activated JNK and synergized with IL-1, but not with PDGF. V12 Cdc42 weakly activated JNK, but synergized with PDGF and not IL-1. Our results imply that Rho GTPases are not directly involved in mediating IL-1-induced JNK activation, or in the potentiation of this activation by PDGF.  (+info)

Alpha-toxin and gamma-toxin jointly promote Staphylococcus aureus virulence in murine septic arthritis. (3/8457)

Septic arthritis is a common and feared complication of staphylococcal infections. Staphylococcus aureus produces a number of potential virulence factors including certain adhesins and enterotoxins. In this study we have assessed the roles of cytolytic toxins in the development of septic arthritis by inoculating mice with S. aureus wild-type strain 8325-4 or isogenic mutants differing in the expression of alpha-, beta-, and gamma-toxin production patterns. Mice inoculated with either an alpha- or beta-toxin mutant showed degrees of inflammation, joint damage, and weight decrease similar to wild-type-inoculated mice. In contrast, mice inoculated with either double (alpha- and gamma-toxin-deficient)- or triple (alpha-, beta-, and gamma-toxin-deficient)-mutant S. aureus strains showed lower frequency and severity of arthritis, measured both clinically and histologically, than mice inoculated with the wild-type strain. We conclude that simultaneous production of alpha- and gamma-toxin is a virulence factor in S. aureus arthritis.  (+info)

Role of Listeria monocytogenes exotoxins listeriolysin and phosphatidylinositol-specific phospholipase C in activation of human neutrophils. (4/8457)

Polymorphonuclear leukocytes (PMN) are essential for resolution of infections with Listeria monocytogenes. The present study investigated the role of the listerial exotoxins listeriolysin (LLO) and phosphatidylinositol-specific phospholipase C (PlcA) in human neutrophil activation. Different Listeria strains, mutated in individual virulence genes, as well as purified LLO were used. Coincubation of human neutrophils with wild-type L. monocytogenes provoked PMN activation, occurring independently of phagocytosis events, with concomitant elastase secretion, leukotriene generation, platelet-activating factor (PAF) synthesis, respiratory burst, and enhanced phosphoinositide hydrolysis. Degranulation and leukotriene formation were noted to be solely dependent on LLO expression, as these features were absent when the LLO-defective mutant EGD- and the avirulent strain L. innocua were used. These effects were fully reproduced by a recombinant L. innocua strain expressing LLO (INN+) and by the purified LLO molecule. LLO secretion was also required for PAF synthesis. However, wild-type L. monocytogenes was more potent in eliciting PAF formation than mutants expressing LLO, suggesting the involvement of additional virulence factors. This was even more obvious for phosphoinositide hydrolysis and respiratory burst: these events were provoked not only by INN+ but also by the LLO-defective mutant EGD- and by a recombinant L. innocua strain producing listerial PlcA. We conclude that human neutrophils react to extracellularly provided listerial exotoxins by rapid cell activation. Listeriolysin is centrally involved in triggering degranulation and lipid mediator generation, and further virulence factors such as PlcA apparently contribute to trigger neutrophil phosphoinositide hydrolysis and respiratory burst. In this way, listerial exotoxins may influence the host defense against infections with L. monocytogenes.  (+info)

Identification of a cytolethal distending toxin gene locus and features of a virulence-associated region in Actinobacillus actinomycetemcomitans. (5/8457)

A genetic locus for a cytolethal distending toxin (CDT) was identified in a polymorphic region of the chromosome of Actinobacillus actinomycetemcomitans, a predominant oral pathogen. The locus was comprised of three open reading frames (ORFs) that had significant amino acid sequence similarity and more than 90% sequence identity to the cdtABC genes of some pathogenic Escherichia coli strains and Haemophilus ducreyi, respectively. Sonic extracts from recombinant E. coli, containing the A. actinomycetemcomitans ORFs, caused the distension and killing of Chinese hamster ovary cells characteristic of a CDT. Monoclonal antibodies made reactive with the CdtA, CdtB, and CdtC proteins of H. ducreyi recognized the corresponding gene products from the recombinant strain. CDT-like activities were no longer expressed by the recombinant strain when an OmegaKan-2 interposon was inserted into the cdtA and cdtB genes. Expression of the CDT-like activities in A. actinomycetemcomitans was strain specific. Naturally occurring expression-negative strains had large deletions within the region of the cdt locus. The cdtABC genes were flanked by an ORF (virulence plasmid protein), a partial ORF (integrase), and DNA sequences (bacteriophage integration site) characteristic of virulence-associated regions. These results provide evidence for a functional CDT in a human oral pathogen.  (+info)

Zonula occludens toxin is a powerful mucosal adjuvant for intranasally delivered antigens. (6/8457)

Zonula occludens toxin (Zot) is produced by toxigenic strains of Vibrio cholerae and has the ability to reversibly alter intestinal epithelial tight junctions, allowing the passage of macromolecules through the mucosal barrier. In the present study, we investigated whether Zot could be exploited to deliver soluble antigens through the nasal mucosa for the induction of antigen-specific systemic and mucosal immune responses. Intranasal immunization of mice with ovalbumin (Ova) and recombinant Zot, either fused to the maltose-binding protein (MBP-Zot) or with a hexahistidine tag (His-Zot), induced anti-Ova serum immunoglobulin G (IgG) titers that were approximately 40-fold higher than those induced by immunization with antigen alone. Interestingly, Zot also stimulated high anti-Ova IgA titers in serum, as well as in vaginal and intestinal secretions. A comparison with Escherichia coli heat-labile enterotoxin (LT) revealed that the adjuvant activity of Zot was only sevenfold lower than that of LT. Moreover, Zot and LT induced similar patterns of Ova-specific IgG subclasses. The subtypes IgG1, IgG2a, and IgG2b were all stimulated, with a predominance of IgG1 and IgG2b. In conclusion, our results highlight Zot as a novel potent mucosal adjuvant of microbial origin.  (+info)

Hyperproduction of alpha-hemolysin in a sigB mutant is associated with elevated SarA expression in Staphylococcus aureus. (7/8457)

To evaluate the role of SigB in modulating the expression of virulence determinants in Staphylococcus aureus, we constructed a sigB mutant of RN6390, a prototypic S. aureus strain. The mutation in the sigB gene was confirmed by the absence of the SigB protein in the mutant on an immunoblot as well as the failure of the mutant to activate sigmaB-dependent promoters (e.g., the sarC promoter) of S. aureus. Phenotypic analysis indicated that both alpha-hemolysin level and fibrinogen-binding capacity were up-regulated in the mutant strain compared with the parental strain. The increase in fibrinogen-binding capacity correlated with enhanced expression of clumping factor and coagulase on immunoblots. The effect of the sigB mutation on the enhanced expression of the alpha-hemolysin gene (hla) was primarily transcriptional. Upon complementation with a plasmid containing the sigB gene, hla expression returned to near parental levels in the mutant. Detailed immunoblot analysis as well as a competitive enzyme-linked immunosorbent assay of the cell extract of the sigB mutant with anti-SarA monoclonal antibody 1D1 revealed that the expression of SarA was higher in the mutant than in the parental control. Despite an elevated SarA level, the transcription of RNAII and RNAIII of the agr locus remained unaltered in the sigB mutant. Because of a lack of perturbation in agr, we hypothesize that inactivation of sigB leads to increased expression of SarA which, in turn, modulates target genes via an agr-independent but SarA-dependent pathway.  (+info)

Responses of human intestinal microvascular endothelial cells to Shiga toxins 1 and 2 and pathogenesis of hemorrhagic colitis. (8/8457)

Endothelial damage is characteristic of infection with Shiga toxin (Stx)-producing Escherichia coli (STEC). Because Stx-mediated endothelial cell damage at the site of infection may lead to the characteristic hemorrhagic colitis of STEC infection, we compared the effects of Stx1 and Stx2 on primary and transformed human intestinal microvascular endothelial cells (HIMEC) to those on macrovascular endothelial cells from human saphenous vein (HSVEC). Adhesion molecule, interleukin-8 (IL-8), and Stx receptor expression, the effects of cytokine activation and Stx toxins on these responses, and Stx1 and Stx2 binding kinetics and bioactivity were measured. Adhesion molecule and IL-8 expression increased in activated HIMEC, but these responses were blunted in the presence of toxin, especially in the presence of Stx1. In contrast to HSVEC, unstimulated HIMEC constitutively expressed Stx receptor at high levels, bound large amounts of toxin, were highly sensitive to toxin, and were not further sensitized by cytokines. Although the binding capacities of HIMEC for Stx1 and Stx2 were comparable, the binding affinity of Stx1 to HIMEC was 50-fold greater than that of Stx2. Nonetheless, Stx2 was more toxic to HIMEC than an equivalent amount of Stx1. The decreased binding affinity and increased toxicity for HIMEC of Stx2 compared to those of Stx1 may be relevant to the preponderance of Stx2-producing STEC involved in the pathogenesis of hemorrhagic colitis and its systemic complications. The differences between primary and transformed HIMEC in these responses were negligible. We conclude that transformed HIMEC lines could represent a simple physiologically relevant model to study the role of Stx in the pathogenesis of hemorrhagic colitis.  (+info)

Bacterial toxins are poisonous substances produced and released by bacteria. They can cause damage to the host organism's cells and tissues, leading to illness or disease. Bacterial toxins can be classified into two main types: exotoxins and endotoxins.

Exotoxins are proteins secreted by bacterial cells that can cause harm to the host. They often target specific cellular components or pathways, leading to tissue damage and inflammation. Some examples of exotoxins include botulinum toxin produced by Clostridium botulinum, which causes botulism; diphtheria toxin produced by Corynebacterium diphtheriae, which causes diphtheria; and tetanus toxin produced by Clostridium tetani, which causes tetanus.

Endotoxins, on the other hand, are components of the bacterial cell wall that are released when the bacteria die or divide. They consist of lipopolysaccharides (LPS) and can cause a generalized inflammatory response in the host. Endotoxins can be found in gram-negative bacteria such as Escherichia coli and Pseudomonas aeruginosa.

Bacterial toxins can cause a wide range of symptoms depending on the type of toxin, the dose, and the site of infection. They can lead to serious illnesses or even death if left untreated. Vaccines and antibiotics are often used to prevent or treat bacterial infections and reduce the risk of severe complications from bacterial toxins.

Cholera toxin is a protein toxin produced by the bacterium Vibrio cholerae, which causes the infectious disease cholera. The toxin is composed of two subunits, A and B, and its primary mechanism of action is to alter the normal function of cells in the small intestine.

The B subunit of the toxin binds to ganglioside receptors on the surface of intestinal epithelial cells, allowing the A subunit to enter the cell. Once inside, the A subunit activates a signaling pathway that results in the excessive secretion of chloride ions and water into the intestinal lumen, leading to profuse, watery diarrhea, dehydration, and other symptoms associated with cholera.

Cholera toxin is also used as a research tool in molecular biology and immunology due to its ability to modulate cell signaling pathways. It has been used to study the mechanisms of signal transduction, protein trafficking, and immune responses.

ADP Ribose Transferases are a group of enzymes that catalyze the transfer of ADP-ribose groups from donor molecules, such as NAD+ (nicotinamide adenine dinucleotide), to specific acceptor molecules. This transfer process plays a crucial role in various cellular processes, including DNA repair, gene expression regulation, and modulation of protein function.

The reaction catalyzed by ADP Ribose Transferases can be represented as follows:

Donor (NAD+ or NADP+) + Acceptor → Product (NR + ADP-ribosylated acceptor)

There are two main types of ADP Ribose Transferases based on their function and the type of modification they perform:

1. Poly(ADP-ribose) polymerases (PARPs): These enzymes add multiple ADP-ribose units to a single acceptor protein, forming long, linear, or branched chains known as poly(ADP-ribose) (PAR). PARylation is involved in DNA repair, genomic stability, and cell death pathways.
2. Monomeric ADP-ribosyltransferases: These enzymes transfer a single ADP-ribose unit to an acceptor protein, which is called mono(ADP-ribosyl)ation. This modification can regulate protein function, localization, and stability in various cellular processes, such as signal transduction, inflammation, and stress response.

Dysregulation of ADP Ribose Transferases has been implicated in several diseases, including cancer, neurodegenerative disorders, and cardiovascular diseases. Therefore, understanding the function and regulation of these enzymes is essential for developing novel therapeutic strategies to target these conditions.

Streptolysins are exotoxins produced by certain strains of Streptococcus bacteria, primarily Group A Streptococcus (GAS). These toxins are classified into two types: streptolysin O (SLO) and streptolysin S (SLS).

1. Streptolysin O (SLO): It is a protein exotoxin that exhibits oxygen-labile hemolytic activity, meaning it can lyse or destroy red blood cells in the presence of oxygen. SLO is capable of entering host cells and causing various cellular damages, including inhibition of phagocytosis, modulation of immune responses, and induction of apoptosis (programmed cell death).

2. Streptolysin S (SLS): It is a non-protein, oxygen-stable hemolysin that can also lyse red blood cells but does so independently of oxygen presence. SLS is more heat-resistant than SLO and has a stronger ability to penetrate host cell membranes.

Both streptolysins contribute to the virulence of Streptococcus pyogenes, which can cause various clinical infections such as pharyngitis (strep throat), impetigo, scarlet fever, and invasive diseases like necrotizing fasciitis and toxic shock syndrome.

The detection of streptolysin O antibodies (ASO titer) is often used as a diagnostic marker for past or recent GAS infections, particularly in cases of rheumatic fever, where elevated ASO titers indicate ongoing or previous streptococcal infection.

Cytotoxins are substances that are toxic to cells. They can cause damage and death to cells by disrupting their membranes, interfering with their metabolism, or triggering programmed cell death (apoptosis). Cytotoxins can be produced by various organisms such as bacteria, fungi, plants, and animals, and they can also be synthesized artificially.

In medicine, cytotoxic drugs are used to treat cancer because they selectively target and kill rapidly dividing cells, including cancer cells. Examples of cytotoxic drugs include chemotherapy agents such as doxorubicin, cyclophosphamide, and methotrexate. However, these drugs can also damage normal cells, leading to side effects such as nausea, hair loss, and immune suppression.

It's important to note that cytotoxins are not the same as toxins, which are poisonous substances produced by living organisms that can cause harm to other organisms. While all cytotoxins are toxic to cells, not all toxins are cytotoxic. Some toxins may have systemic effects on organs or tissues rather than directly killing cells.

T-2 toxin is a type B trichothecene mycotoxin, which is a secondary metabolite produced by certain Fusarium species of fungi. It is a low molecular weight sesquiterpene epoxide that is chemically stable and has a high toxicity profile. T-2 toxin can contaminate crops in the field or during storage, and it is often found in grains such as corn, wheat, barley, and oats.

T-2 toxin has a variety of adverse health effects, including nausea, vomiting, diarrhea, abdominal pain, immune suppression, skin irritation, and neurotoxicity. It is also known to have teratogenic and embryotoxic effects in animals, and it is considered a potential human carcinogen by some agencies.

Exposure to T-2 toxin can occur through ingestion, inhalation, or skin contact. Ingestion is the most common route of exposure, particularly in areas where contaminated grains are used as a food source. Inhalation exposure can occur during agricultural activities such as harvesting and processing contaminated crops. Skin contact with T-2 toxin can cause irritation and inflammation.

Prevention of T-2 toxin exposure involves good agricultural practices, including crop rotation, use of resistant varieties, and proper storage conditions. Monitoring of T-2 toxin levels in food and feed is also important to ensure that exposure limits are not exceeded.

Enterotoxins are types of toxic substances that are produced by certain microorganisms, such as bacteria. These toxins are specifically designed to target and affect the cells in the intestines, leading to symptoms such as diarrhea, vomiting, and abdominal cramps. One well-known example of an enterotoxin is the toxin produced by Staphylococcus aureus bacteria, which can cause food poisoning. Another example is the cholera toxin produced by Vibrio cholerae, which can cause severe diarrhea and dehydration. Enterotoxins work by interfering with the normal functioning of intestinal cells, leading to fluid accumulation in the intestines and subsequent symptoms.

Hemolysins are a type of protein toxin produced by certain bacteria, fungi, and plants that have the ability to damage and destroy red blood cells (erythrocytes), leading to their lysis or hemolysis. This results in the release of hemoglobin into the surrounding environment. Hemolysins can be classified into two main categories:

1. Exotoxins: These are secreted by bacteria and directly damage host cells. They can be further divided into two types:
* Membrane attack complex/perforin-like proteins (MACPF): These hemolysins create pores in the membrane of red blood cells, disrupting their integrity and causing lysis. Examples include alpha-hemolysin from Staphylococcus aureus and streptolysin O from Streptococcus pyogenes.
* Enzymatic hemolysins: These hemolysins are enzymes that degrade specific components of the red blood cell membrane, ultimately leading to lysis. An example is streptolysin S from Streptococcus pyogenes, which is a thiol-activated, oxygen-labile hemolysin.
2. Endotoxins: These are part of the outer membrane of Gram-negative bacteria and can cause indirect hemolysis by activating the complement system or by stimulating the release of inflammatory mediators from host cells.

Hemolysins play a significant role in bacterial pathogenesis, contributing to tissue damage, impaired immune responses, and disease progression.

Biological toxins are poisonous substances that are produced by living organisms such as bacteria, plants, and animals. They can cause harm to humans, animals, or the environment. Biological toxins can be classified into different categories based on their mode of action, such as neurotoxins (affecting the nervous system), cytotoxins (damaging cells), and enterotoxins (causing intestinal damage).

Examples of biological toxins include botulinum toxin produced by Clostridium botulinum bacteria, tetanus toxin produced by Clostridium tetani bacteria, ricin toxin from the castor bean plant, and saxitoxin produced by certain types of marine algae.

Biological toxins can cause a range of symptoms depending on the type and amount of toxin ingested or exposed to, as well as the route of exposure (e.g., inhalation, ingestion, skin contact). They can cause illnesses ranging from mild to severe, and some can be fatal if not treated promptly and effectively.

Prevention and control measures for biological toxins include good hygiene practices, vaccination against certain toxin-producing bacteria, avoidance of contaminated food or water sources, and personal protective equipment (PPE) when handling or working with potential sources of toxins.

Exotoxins are a type of toxin that are produced and released by certain bacteria into their external environment, including the surrounding tissues or host's bloodstream. These toxins can cause damage to cells and tissues, and contribute to the symptoms and complications associated with bacterial infections.

Exotoxins are typically proteins, and they can have a variety of effects on host cells, depending on their specific structure and function. Some exotoxins act by disrupting the cell membrane, leading to cell lysis or death. Others interfere with intracellular signaling pathways, alter gene expression, or modify host immune responses.

Examples of bacterial infections that are associated with the production of exotoxins include:

* Botulism, caused by Clostridium botulinum
* Diphtheria, caused by Corynebacterium diphtheriae
* Tetanus, caused by Clostridium tetani
* Pertussis (whooping cough), caused by Bordetella pertussis
* Food poisoning, caused by Staphylococcus aureus or Bacillus cereus

Exotoxins can be highly potent and dangerous, and some have been developed as biological weapons. However, many exotoxins are also used in medicine for therapeutic purposes, such as botulinum toxin (Botox) for the treatment of wrinkles or dystonia.

Bacterial proteins are a type of protein that are produced by bacteria as part of their structural or functional components. These proteins can be involved in various cellular processes, such as metabolism, DNA replication, transcription, and translation. They can also play a role in bacterial pathogenesis, helping the bacteria to evade the host's immune system, acquire nutrients, and multiply within the host.

Bacterial proteins can be classified into different categories based on their function, such as:

1. Enzymes: Proteins that catalyze chemical reactions in the bacterial cell.
2. Structural proteins: Proteins that provide structural support and maintain the shape of the bacterial cell.
3. Signaling proteins: Proteins that help bacteria to communicate with each other and coordinate their behavior.
4. Transport proteins: Proteins that facilitate the movement of molecules across the bacterial cell membrane.
5. Toxins: Proteins that are produced by pathogenic bacteria to damage host cells and promote infection.
6. Surface proteins: Proteins that are located on the surface of the bacterial cell and interact with the environment or host cells.

Understanding the structure and function of bacterial proteins is important for developing new antibiotics, vaccines, and other therapeutic strategies to combat bacterial infections.

Tetanus toxin, also known as tetanospasmin, is a potent neurotoxin produced by the bacterium Clostridium tetani. This toxin binds to nerve endings and is transported to the nervous system's inhibitory neurons, where it blocks the release of inhibitory neurotransmitters, particularly glycine and GABA (gamma-aminobutyric acid). As a result, it causes uncontrolled muscle contractions or spasms, which are the hallmark symptoms of tetanus disease.

The toxin has two main components: an N-terminal portion called the light chain, which is the enzymatically active part that inhibits neurotransmitter release, and a C-terminal portion called the heavy chain, which facilitates the toxin's entry into neurons. The heavy chain also contains a binding domain that allows the toxin to recognize specific receptors on nerve cells.

Tetanus toxin is one of the most potent toxins known, with an estimated human lethal dose of just 2.5-3 nanograms per kilogram of body weight when introduced into the bloodstream. Fortunately, tetanus can be prevented through vaccination with the tetanus toxoid, which is part of the standard diphtheria-tetanus-pertussis (DTaP or Tdap) immunization series for children and adolescents and the tetanus-diphtheria (Td) booster for adults.

Adenosine diphosphate ribose (ADPR) is a molecule that plays a role in various cellular processes, including the modification of proteins and the regulation of enzyme activity. It is formed by the attachment of a diphosphate group and a ribose sugar to the adenine base of a nucleotide. ADPR is involved in the transfer of chemical energy within cells and is also a precursor in the synthesis of other important molecules, such as NAD+ (nicotinamide adenine dinucleotide). It should be noted that ADPR is not a medication or a drug, but rather a naturally occurring biomolecule.

Diphtheria toxin is a potent exotoxin produced by the bacterium Corynebacterium diphtheriae, which causes the disease diphtheria. This toxin is composed of two subunits: A and B. The B subunit helps the toxin bind to and enter host cells, while the A subunit inhibits protein synthesis within those cells, leading to cell damage and tissue destruction.

The toxin can cause a variety of symptoms depending on the site of infection. In respiratory diphtheria, it typically affects the nose, throat, and tonsils, causing a thick gray or white membrane to form over the affected area, making breathing and swallowing difficult. In cutaneous diphtheria, it infects the skin, leading to ulcers and necrosis.

Diphtheria toxin can also have systemic effects, such as damage to the heart, nerves, and kidneys, which can be life-threatening if left untreated. Fortunately, diphtheria is preventable through vaccination with the diphtheria, tetanus, and pertussis (DTaP or Tdap) vaccine.

Antitoxins are substances, typically antibodies, that neutralize toxins produced by bacteria or other harmful organisms. They work by binding to the toxin molecules and rendering them inactive, preventing them from causing harm to the body. Antitoxins can be produced naturally by the immune system during an infection, or they can be administered artificially through immunization or passive immunotherapy. In a medical context, antitoxins are often used as a treatment for certain types of bacterial infections, such as diphtheria and botulism, to help counteract the effects of the toxins produced by the bacteria.

Adenylate cyclase toxin is a type of exotoxin produced by certain bacteria, including Bordetella pertussis (the causative agent of whooping cough) and Vibrio cholerae. This toxin functions by entering host cells and catalyzing the conversion of adenosine triphosphate (ATP) to cyclic adenosine monophosphate (cAMP), leading to increased intracellular cAMP levels.

The elevated cAMP levels can disrupt various cellular processes, such as signal transduction and ion transport, resulting in a range of physiological effects that contribute to the pathogenesis of the bacterial infection. For example, in the case of Bordetella pertussis, adenylate cyclase toxin impairs the function of immune cells, allowing the bacteria to evade host defenses and establish a successful infection.

In summary, adenylate cyclase toxin is a virulence factor produced by certain pathogenic bacteria that increases intracellular cAMP levels in host cells, leading to disrupted cellular processes and contributing to bacterial pathogenesis.

'Escherichia coli (E. coli) proteins' refer to the various types of proteins that are produced and expressed by the bacterium Escherichia coli. These proteins play a critical role in the growth, development, and survival of the organism. They are involved in various cellular processes such as metabolism, DNA replication, transcription, translation, repair, and regulation.

E. coli is a gram-negative, facultative anaerobe that is commonly found in the intestines of warm-blooded organisms. It is widely used as a model organism in scientific research due to its well-studied genetics, rapid growth, and ability to be easily manipulated in the laboratory. As a result, many E. coli proteins have been identified, characterized, and studied in great detail.

Some examples of E. coli proteins include enzymes involved in carbohydrate metabolism such as lactase, sucrase, and maltose; proteins involved in DNA replication such as the polymerases, single-stranded binding proteins, and helicases; proteins involved in transcription such as RNA polymerase and sigma factors; proteins involved in translation such as ribosomal proteins, tRNAs, and aminoacyl-tRNA synthetases; and regulatory proteins such as global regulators, two-component systems, and transcription factors.

Understanding the structure, function, and regulation of E. coli proteins is essential for understanding the basic biology of this important organism, as well as for developing new strategies for combating bacterial infections and improving industrial processes involving bacteria.

Botulinum toxins type A are neurotoxins produced by the bacterium Clostridium botulinum and related species. These toxins act by blocking the release of acetylcholine at the neuromuscular junction, leading to muscle paralysis. Botulinum toxin type A is used in medical treatments for various conditions characterized by muscle spasticity or excessive muscle activity, such as cervical dystonia, blepharospasm, strabismus, and chronic migraine. It is also used cosmetically to reduce the appearance of wrinkles by temporarily paralyzing the muscles that cause them. The commercial forms of botulinum toxin type A include Botox, Dysport, and Xeomin.

Marine toxins are toxic compounds that are produced by certain marine organisms, including algae, bacteria, and various marine animals such as shellfish, jellyfish, and snails. These toxins can cause a range of illnesses and symptoms in humans who consume contaminated seafood or come into direct contact with the toxin-producing organisms. Some of the most well-known marine toxins include:

1. Saxitoxin: Produced by certain types of algae, saxitoxin can cause paralytic shellfish poisoning (PSP) in humans who consume contaminated shellfish. Symptoms of PSP include tingling and numbness of the lips, tongue, and fingers, followed by muscle weakness, paralysis, and in severe cases, respiratory failure.
2. Domoic acid: Produced by certain types of algae, domoic acid can cause amnesic shellfish poisoning (ASP) in humans who consume contaminated shellfish. Symptoms of ASP include nausea, vomiting, diarrhea, abdominal cramps, headache, and memory loss.
3. Okadaic acid: Produced by certain types of algae, okadaic acid can cause diarrhetic shellfish poisoning (DSP) in humans who consume contaminated shellfish. Symptoms of DSP include nausea, vomiting, diarrhea, abdominal cramps, and fever.
4. Ciguatoxin: Produced by certain types of dinoflagellates, ciguatoxin can cause ciguatera fish poisoning (CFP) in humans who consume contaminated fish. Symptoms of CFP include nausea, vomiting, diarrhea, abdominal pain, and neurological symptoms such as tingling and numbness of the lips, tongue, and fingers, as well as reversal of hot and cold sensations.
5. Tetrodotoxin: Found in certain types of pufferfish, tetrodotoxin can cause a severe form of food poisoning known as pufferfish poisoning or fugu poisoning. Symptoms of tetrodotoxin poisoning include numbness of the lips and tongue, difficulty speaking, muscle weakness, paralysis, and respiratory failure.

Prevention measures for these types of seafood poisoning include avoiding consumption of fish and shellfish that are known to be associated with these toxins, as well as cooking and preparing seafood properly before eating it. Additionally, monitoring programs have been established in many countries to monitor the levels of these toxins in seafood and issue warnings when necessary.

Botulinum toxins are neurotoxic proteins produced by the bacterium Clostridium botulinum and related species. They are the most potent naturally occurring toxins, and are responsible for the paralytic illness known as botulism. There are seven distinct botulinum toxin serotypes (A-G), each of which targets specific proteins in the nervous system, leading to inhibition of neurotransmitter release and subsequent muscle paralysis.

In clinical settings, botulinum toxins have been used for therapeutic purposes due to their ability to cause temporary muscle relaxation. Botulinum toxin type A (Botox) is the most commonly used serotype in medical treatments, including management of dystonias, spasticity, migraines, and certain neurological disorders. Additionally, botulinum toxins are widely employed in aesthetic medicine for reducing wrinkles and fine lines by temporarily paralyzing facial muscles.

It is important to note that while botulinum toxins have therapeutic benefits when used appropriately, they can also pose significant health risks if misused or improperly handled. Proper medical training and supervision are essential for safe and effective utilization of these powerful toxins.

Virulence factors are characteristics or components of a microorganism, such as bacteria, viruses, fungi, or parasites, that contribute to its ability to cause damage or disease in a host organism. These factors can include various structures, enzymes, or toxins that allow the pathogen to evade the host's immune system, attach to and invade host tissues, obtain nutrients from the host, or damage host cells directly.

Examples of virulence factors in bacteria include:

1. Endotoxins: lipopolysaccharides found in the outer membrane of Gram-negative bacteria that can trigger a strong immune response and inflammation.
2. Exotoxins: proteins secreted by some bacteria that have toxic effects on host cells, such as botulinum toxin produced by Clostridium botulinum or diphtheria toxin produced by Corynebacterium diphtheriae.
3. Adhesins: structures that help the bacterium attach to host tissues, such as fimbriae or pili in Escherichia coli.
4. Capsules: thick layers of polysaccharides or proteins that surround some bacteria and protect them from the host's immune system, like those found in Streptococcus pneumoniae or Klebsiella pneumoniae.
5. Invasins: proteins that enable bacteria to invade and enter host cells, such as internalins in Listeria monocytogenes.
6. Enzymes: proteins that help bacteria obtain nutrients from the host by breaking down various molecules, like hemolysins that lyse red blood cells to release iron or hyaluronidases that degrade connective tissue.

Understanding virulence factors is crucial for developing effective strategies to prevent and treat infectious diseases caused by these microorganisms.

'Bacillus anthracis' is the scientific name for the bacterium that causes anthrax, a serious and potentially fatal infectious disease. This gram-positive, spore-forming rod-shaped bacterium can be found in soil and commonly affects animals such as sheep, goats, and cattle. Anthrax can manifest in several forms, including cutaneous (skin), gastrointestinal, and inhalation anthrax, depending on the route of infection.

The spores of Bacillus anthracis are highly resistant to environmental conditions and can survive for years, making them a potential agent for bioterrorism or biowarfare. When inhaled, ingested, or introduced through breaks in the skin, these spores can germinate into vegetative bacteria that produce potent exotoxins responsible for anthrax symptoms and complications.

It is essential to distinguish Bacillus anthracis from other Bacillus species due to its public health significance and potential use as a biological weapon. Proper identification, prevention strategies, and medical countermeasures are crucial in mitigating the risks associated with this bacterium.

Rho GTP-binding proteins are a subfamily of the Ras superfamily of small GTPases, which function as molecular switches in various cellular signaling pathways. These proteins play crucial roles in regulating diverse cellular processes such as actin cytoskeleton dynamics, gene expression, cell cycle progression, and cell migration.

Rho GTP-binding proteins cycle between an active GTP-bound state and an inactive GDP-bound state. In the active state, they interact with various downstream effectors to regulate their respective cellular functions. Guanine nucleotide exchange factors (GEFs) activate Rho GTP-binding proteins by promoting the exchange of GDP for GTP, while GTPase-activating proteins (GAPs) inactivate them by enhancing their intrinsic GTP hydrolysis activity.

There are several members of the Rho GTP-binding protein family, including RhoA, RhoB, RhoC, Rac1, Rac2, Rac3, Cdc42, and Rnd proteins, each with distinct functions and downstream effectors. Dysregulation of Rho GTP-binding proteins has been implicated in various human diseases, including cancer, cardiovascular disease, neurological disorders, and inflammatory diseases.

Shiga toxins are a type of protein toxin produced by certain strains of bacteria, including some types of Escherichia coli (E. coli) and Shigella dysenteriae. These toxins get their name from Dr. Kiyoshi Shiga, who first discovered them in the late 19th century.

Shiga toxins are classified into two main types: Shiga toxin 1 (Stx1) and Shiga toxin 2 (Stx2). Both types of toxins are similar in structure and function, but they differ in their potency and genetic makeup. Shiga toxins inhibit protein synthesis in cells by removing an adenine residue from a specific region of the 28S rRNA molecule in the ribosome, which ultimately leads to cell death.

These toxins can cause severe damage to the lining of the intestines and are associated with hemorrhagic colitis, a potentially life-threatening condition characterized by bloody diarrhea, abdominal cramps, and fever. In some cases, Shiga toxins can also enter the bloodstream and cause systemic complications such as hemolytic uremic syndrome (HUS), which is characterized by kidney failure, anemia, and thrombocytopenia.

Exposure to Shiga toxins typically occurs through ingestion of contaminated food or water, or through direct contact with infected individuals or animals. Preventive measures include good hygiene practices, such as thorough handwashing, cooking meats thoroughly, and avoiding unpasteurized dairy products and untreated water.

Molecular sequence data refers to the specific arrangement of molecules, most commonly nucleotides in DNA or RNA, or amino acids in proteins, that make up a biological macromolecule. This data is generated through laboratory techniques such as sequencing, and provides information about the exact order of the constituent molecules. This data is crucial in various fields of biology, including genetics, evolution, and molecular biology, allowing for comparisons between different organisms, identification of genetic variations, and studies of gene function and regulation.

Furin is not a medical condition or disease, but rather it is a type of enzyme that belongs to the group of proteases. It's also known as paired basic amino acid cleaving enzyme (PACE) or convertase 6.

Furin plays an essential role in processing and activating various proteins in the body, particularly those involved in cell signaling, growth regulation, and viral infectivity. Furin works by cutting or cleaving specific amino acid sequences in proteins, allowing them to become active and perform their functions.

In a medical context, furin is often discussed in relation to its role in activating certain viruses, such as HIV, influenza, and coronaviruses (including SARS-CoV-2). Inhibiting furin activity has been explored as a potential therapeutic strategy for treating these viral infections.

Colicins are a type of protein produced by certain strains of bacteria, specifically Escherichia coli (E. coli). They have antibacterial properties and function by punching holes in the membranes of other bacterial cells, leading to their death. Colicins are plasmid-encoded bacteriocins, which means they are encoded on plasmids, small circular DNA molecules that can exist independently of the chromosomal DNA.

Colicins are produced by E. coli as a defense mechanism against other competing bacteria in their environment. They are released when the producing cell dies or undergoes programmed cell death (PCD), also known as bacterial suicide. Once released, colicins can bind to specific receptors on the surface of sensitive target cells and enter them through the membrane.

Once inside the target cell, colicins disrupt the cell's functions by interacting with essential proteins or nucleic acids. They can act in various ways, such as cleaving DNA, inhibiting protein synthesis, or creating pores in the membrane that allow for the leakage of essential molecules and ions, ultimately leading to the death of the target cell.

It is important to note that colicins are not harmful to humans or animals and have been studied as potential therapeutic agents against bacterial infections. However, their use as antibiotics has not yet been approved for clinical use due to various challenges, such as developing effective delivery systems and addressing concerns about promoting bacterial resistance.

An amino acid sequence is the specific order of amino acids in a protein or peptide molecule, formed by the linking of the amino group (-NH2) of one amino acid to the carboxyl group (-COOH) of another amino acid through a peptide bond. The sequence is determined by the genetic code and is unique to each type of protein or peptide. It plays a crucial role in determining the three-dimensional structure and function of proteins.

Shiga toxin 2 (Stx2) is a protein toxin produced by certain strains of the bacterium Escherichia coli (E. coli), specifically those that belong to serotype O157:H7 and some other Shiga toxin-producing E. coli (STEC) or enterohemorrhagic E. coli (EHEC).

Stx2 is named after Dr. Kiyoshi Shiga, who first discovered the related Shiga toxin in 1898. It is a powerful cytotoxin that can cause damage to cells lining the intestines and other organs. The toxin inhibits protein synthesis in the cells by removing an adenine residue from the 28S rRNA of the 60S ribosomal subunit, leading to cell death.

Exposure to Stx2 can occur through ingestion of contaminated food or water, or direct contact with infected animals or their feces. In severe cases, it can lead to hemorrhagic colitis, which is characterized by bloody diarrhea and abdominal cramps, and hemolytic uremic syndrome (HUS), a serious complication that can cause kidney failure, anemia, and neurological problems.

It's important to note that Stx2 has two major subtypes, Stx2a and Stx2b, which differ in their biological activities and clinical significance. Stx2a is considered more potent than Stx2b and is associated with a higher risk of developing HUS.

Pertussis toxin is an exotoxin produced by the bacterium Bordetella pertussis, which is responsible for causing whooping cough in humans. This toxin has several effects on the host organism, including:

1. Adenylyl cyclase activation: Pertussis toxin enters the host cell and modifies a specific G protein (Gαi), leading to the continuous activation of adenylyl cyclase. This results in increased levels of intracellular cAMP, which disrupts various cellular processes.
2. Inhibition of immune response: Pertussis toxin impairs the host's immune response by inhibiting the migration and function of immune cells like neutrophils and macrophages. It also interferes with antigen presentation and T-cell activation, making it difficult for the body to clear the infection.
3. Increased inflammation: The continuous activation of adenylyl cyclase by pertussis toxin leads to increased production of proinflammatory cytokines, contributing to the severe coughing fits and other symptoms associated with whooping cough.

Pertussis toxin is an essential virulence factor for Bordetella pertussis, and its effects contribute significantly to the pathogenesis of whooping cough. Vaccination against pertussis includes inactivated or genetically detoxified forms of pertussis toxin, which provide immunity without causing disease symptoms.

Shiga toxin 1 (Stx1) is a protein toxin produced by certain strains of the bacterium Escherichia coli (E. coli), specifically those that belong to serotype O157:H7 and some other Shiga toxin-producing E. coli (STEC) or enterohemorrhagic E. coli (EHEC).

Shiga toxins are named after Kiyoshi Shiga, who discovered the first strain of E. coli that produces this toxin in 1897. These toxins inhibit protein synthesis in eukaryotic cells and cause damage to the endothelial cells lining blood vessels, which can lead to various clinical manifestations such as hemorrhagic colitis (bloody diarrhea) and hemolytic uremic syndrome (HUS), a severe complication that can result in kidney failure.

Shiga toxin 1 is composed of two subunits, A and B. The B subunit binds to specific glycolipid receptors on the surface of target cells, facilitating the uptake of the toxin into the cell. Once inside the cell, the A subunit inhibits protein synthesis by removing an adenine residue from a specific region of the 28S rRNA molecule in the ribosome, thereby preventing peptide bond formation and leading to cell death.

Shiga toxin 1 is highly toxic and can cause significant morbidity and mortality, particularly in children, the elderly, and immunocompromised individuals. Antibiotics are generally not recommended for the treatment of Shiga toxin-producing E. coli infections because they may increase the risk of developing HUS by inducing bacterial lysis and releasing more toxins into the circulation. Supportive care, hydration, and close monitoring are essential for managing these infections.

Pore-forming cytotoxic proteins are a group of toxins that can create pores or holes in the membranes of cells, leading to cell damage or death. These toxins are produced by various organisms, including bacteria, fungi, and plants, as a defense mechanism or to help establish an infection.

The pore-forming cytotoxic proteins can be divided into two main categories:

1. Membrane attack complex/perforin (MACPF) domain-containing proteins: These are found in many organisms, including humans. They form pores by oligomerizing, or clustering together, in the target cell membrane. An example of this type of toxin is the perforin protein, which is released by cytotoxic T cells and natural killer cells to destroy virus-infected or cancerous cells.
2. Cholesterol-dependent cytolysins (CDCs): These are mainly produced by gram-positive bacteria. They bind to cholesterol in the target cell membrane, forming a prepore structure that then undergoes conformational changes to create a pore. An example of a CDC is alpha-hemolysin from Staphylococcus aureus, which can lyse red blood cells and damage various other cell types.

These pore-forming cytotoxic proteins play a significant role in host-pathogen interactions and have implications for the development of novel therapeutic strategies.

Superantigens are a unique group of antigens that can cause widespread activation of the immune system. They are capable of stimulating large numbers of T-cells (a type of white blood cell) leading to massive cytokine release, which can result in a variety of symptoms such as fever, rash, and potentially life-threatening conditions like toxic shock syndrome. Superantigens are often produced by certain bacteria and viruses. They differ from traditional antigens because they do not need to be processed and presented by antigen-presenting cells to activate T-cells; instead, they directly bind to the major histocompatibility complex class II molecules and the T-cell receptor's variable region, leading to polyclonal T-cell activation.

Immunotoxins are biomolecules that combine the specificity of an antibody with the toxicity of a toxin. They are created by chemically linking a monoclonal antibody (that recognizes and binds to a specific cell surface antigen) to a protein toxin (that inhibits protein synthesis in cells). The immunotoxin selectively binds to the target cell, gets internalized, and releases the toxin into the cytosol, leading to cell death. Immunotoxins have been explored as potential therapeutic agents for targeted cancer therapy and treatment of other diseases.

'Clostridium perfringens' is a type of Gram-positive, rod-shaped, spore-forming bacterium that is commonly found in the environment, including in soil, decaying vegetation, and the intestines of humans and animals. It is a major cause of foodborne illness worldwide, producing several toxins that can lead to symptoms such as diarrhea, abdominal cramps, nausea, and vomiting.

The bacterium can contaminate food during preparation or storage, particularly meat and poultry products. When ingested, the spores of C. perfringens can germinate and produce large numbers of toxin-producing cells in the intestines, leading to food poisoning. The most common form of C. perfringens food poisoning is characterized by symptoms that appear within 6 to 24 hours after ingestion and last for less than 24 hours.

In addition to foodborne illness, C. perfringens can also cause other types of infections, such as gas gangrene, a serious condition that can occur when the bacterium infects a wound and produces toxins that damage surrounding tissues. Gas gangrene is a medical emergency that requires prompt treatment with antibiotics and surgical debridement or amputation of affected tissue.

Prevention measures for C. perfringens food poisoning include proper cooking, handling, and storage of food, as well as rapid cooling of cooked foods to prevent the growth of the bacterium.

'Escherichia coli' (E. coli) is a type of gram-negative, facultatively anaerobic, rod-shaped bacterium that commonly inhabits the intestinal tract of humans and warm-blooded animals. It is a member of the family Enterobacteriaceae and one of the most well-studied prokaryotic model organisms in molecular biology.

While most E. coli strains are harmless and even beneficial to their hosts, some serotypes can cause various forms of gastrointestinal and extraintestinal illnesses in humans and animals. These pathogenic strains possess virulence factors that enable them to colonize and damage host tissues, leading to diseases such as diarrhea, urinary tract infections, pneumonia, and sepsis.

E. coli is a versatile organism with remarkable genetic diversity, which allows it to adapt to various environmental niches. It can be found in water, soil, food, and various man-made environments, making it an essential indicator of fecal contamination and a common cause of foodborne illnesses. The study of E. coli has contributed significantly to our understanding of fundamental biological processes, including DNA replication, gene regulation, and protein synthesis.

Virulence factors in Bordetella pertussis, the bacterium that causes whooping cough, refer to the characteristics or components of the organism that contribute to its ability to cause disease. These virulence factors include:

1. Pertussis Toxin (PT): A protein exotoxin that inhibits the immune response and affects the nervous system, leading to the characteristic paroxysmal cough of whooping cough.
2. Adenylate Cyclase Toxin (ACT): A toxin that increases the levels of cAMP in host cells, disrupting their function and contributing to the pathogenesis of the disease.
3. Filamentous Hemagglutinin (FHA): A surface protein that allows the bacterium to adhere to host cells and evade the immune response.
4. Fimbriae: Hair-like appendages on the surface of the bacterium that facilitate adherence to host cells.
5. Pertactin (PRN): A surface protein that also contributes to adherence and is a common component of acellular pertussis vaccines.
6. Dermonecrotic Toxin: A toxin that causes localized tissue damage and necrosis, contributing to the inflammation and symptoms of whooping cough.
7. Tracheal Cytotoxin: A toxin that damages ciliated epithelial cells in the respiratory tract, impairing mucociliary clearance and increasing susceptibility to infection.

These virulence factors work together to enable Bordetella pertussis to colonize the respiratory tract, evade the host immune response, and cause the symptoms of whooping cough.

Shiga toxins are a type of protein toxin produced by certain strains of bacteria, including some types of Escherichia coli (E. coli) and Shigella dysenteriae. These toxins get their name from Kiyoshi Shiga, the scientist who discovered them in 1897.

Shiga toxins are potent cytotoxins that can cause damage to cells by inhibiting protein synthesis. They consist of two main components: an enzymatically active A subunit and several B subunits that bind to specific receptors on the surface of target cells, facilitating the entry of the A subunit into the cell.

Once inside the cell, the A subunit cleaves a crucial component of the protein synthesis machinery called ribosome, leading to cell death or dysfunction. Shiga toxins can cause severe illnesses such as hemorrhagic colitis and hemolytic uremic syndrome (HUS), which can be life-threatening in some cases.

It's worth noting that Shiga toxin-producing E. coli (STEC) infections are often foodborne, and they can cause a range of symptoms from mild diarrhea to severe abdominal cramps, bloody diarrhea, and kidney failure. Prevention measures include proper food handling, cooking meat thoroughly, washing fruits and vegetables, and practicing good hygiene.

A cell membrane, also known as the plasma membrane, is a thin semi-permeable phospholipid bilayer that surrounds all cells in animals, plants, and microorganisms. It functions as a barrier to control the movement of substances in and out of the cell, allowing necessary molecules such as nutrients, oxygen, and signaling molecules to enter while keeping out harmful substances and waste products. The cell membrane is composed mainly of phospholipids, which have hydrophilic (water-loving) heads and hydrophobic (water-fearing) tails. This unique structure allows the membrane to be flexible and fluid, yet selectively permeable. Additionally, various proteins are embedded in the membrane that serve as channels, pumps, receptors, and enzymes, contributing to the cell's overall functionality and communication with its environment.

Molecular models are three-dimensional representations of molecular structures that are used in the field of molecular biology and chemistry to visualize and understand the spatial arrangement of atoms and bonds within a molecule. These models can be physical or computer-generated and allow researchers to study the shape, size, and behavior of molecules, which is crucial for understanding their function and interactions with other molecules.

Physical molecular models are often made up of balls (representing atoms) connected by rods or sticks (representing bonds). These models can be constructed manually using materials such as plastic or wooden balls and rods, or they can be created using 3D printing technology.

Computer-generated molecular models, on the other hand, are created using specialized software that allows researchers to visualize and manipulate molecular structures in three dimensions. These models can be used to simulate molecular interactions, predict molecular behavior, and design new drugs or chemicals with specific properties. Overall, molecular models play a critical role in advancing our understanding of molecular structures and their functions.

Hemolysis is the destruction or breakdown of red blood cells, resulting in the release of hemoglobin into the surrounding fluid (plasma). This process can occur due to various reasons such as chemical agents, infections, autoimmune disorders, mechanical trauma, or genetic abnormalities. Hemolysis may lead to anemia and jaundice, among other complications. It is essential to monitor hemolysis levels in patients undergoing medical treatments that might cause this condition.

Protein binding, in the context of medical and biological sciences, refers to the interaction between a protein and another molecule (known as the ligand) that results in a stable complex. This process is often reversible and can be influenced by various factors such as pH, temperature, and concentration of the involved molecules.

In clinical chemistry, protein binding is particularly important when it comes to drugs, as many of them bind to proteins (especially albumin) in the bloodstream. The degree of protein binding can affect a drug's distribution, metabolism, and excretion, which in turn influence its therapeutic effectiveness and potential side effects.

Protein-bound drugs may be less available for interaction with their target tissues, as only the unbound or "free" fraction of the drug is active. Therefore, understanding protein binding can help optimize dosing regimens and minimize adverse reactions.

Bacterial antigens are substances found on the surface or produced by bacteria that can stimulate an immune response in a host organism. These antigens can be proteins, polysaccharides, teichoic acids, lipopolysaccharides, or other molecules that are recognized as foreign by the host's immune system.

When a bacterial antigen is encountered by the host's immune system, it triggers a series of responses aimed at eliminating the bacteria and preventing infection. The host's immune system recognizes the antigen as foreign through the use of specialized receptors called pattern recognition receptors (PRRs), which are found on various immune cells such as macrophages, dendritic cells, and neutrophils.

Once a bacterial antigen is recognized by the host's immune system, it can stimulate both the innate and adaptive immune responses. The innate immune response involves the activation of inflammatory pathways, the recruitment of immune cells to the site of infection, and the production of antimicrobial peptides.

The adaptive immune response, on the other hand, involves the activation of T cells and B cells, which are specific to the bacterial antigen. These cells can recognize and remember the antigen, allowing for a more rapid and effective response upon subsequent exposures.

Bacterial antigens are important in the development of vaccines, as they can be used to stimulate an immune response without causing disease. By identifying specific bacterial antigens that are associated with virulence or pathogenicity, researchers can develop vaccines that target these antigens and provide protection against infection.

A cell line is a culture of cells that are grown in a laboratory for use in research. These cells are usually taken from a single cell or group of cells, and they are able to divide and grow continuously in the lab. Cell lines can come from many different sources, including animals, plants, and humans. They are often used in scientific research to study cellular processes, disease mechanisms, and to test new drugs or treatments. Some common types of human cell lines include HeLa cells (which come from a cancer patient named Henrietta Lacks), HEK293 cells (which come from embryonic kidney cells), and HUVEC cells (which come from umbilical vein endothelial cells). It is important to note that cell lines are not the same as primary cells, which are cells that are taken directly from a living organism and have not been grown in the lab.

Tertiary protein structure refers to the three-dimensional arrangement of all the elements (polypeptide chains) of a single protein molecule. It is the highest level of structural organization and results from interactions between various side chains (R groups) of the amino acids that make up the protein. These interactions, which include hydrogen bonds, ionic bonds, van der Waals forces, and disulfide bridges, give the protein its unique shape and stability, which in turn determines its function. The tertiary structure of a protein can be stabilized by various factors such as temperature, pH, and the presence of certain ions. Any changes in these factors can lead to denaturation, where the protein loses its tertiary structure and thus its function.

Staphylococcus aureus is a type of gram-positive, round (coccal) bacterium that is commonly found on the skin and mucous membranes of warm-blooded animals and humans. It is a facultative anaerobe, which means it can grow in the presence or absence of oxygen.

Staphylococcus aureus is known to cause a wide range of infections, from mild skin infections such as pimples, impetigo, and furuncles (boils) to more severe and potentially life-threatening infections such as pneumonia, endocarditis, osteomyelitis, and sepsis. It can also cause food poisoning and toxic shock syndrome.

The bacterium is often resistant to multiple antibiotics, including methicillin, which has led to the emergence of methicillin-resistant Staphylococcus aureus (MRSA) strains that are difficult to treat. Proper hand hygiene and infection control practices are critical in preventing the spread of Staphylococcus aureus and MRSA.

GTP-binding proteins, also known as G proteins, are a family of molecular switches present in many organisms, including humans. They play a crucial role in signal transduction pathways, particularly those involved in cellular responses to external stimuli such as hormones, neurotransmitters, and sensory signals like light and odorants.

G proteins are composed of three subunits: α, β, and γ. The α-subunit binds GTP (guanosine triphosphate) and acts as the active component of the complex. When a G protein-coupled receptor (GPCR) is activated by an external signal, it triggers a conformational change in the associated G protein, allowing the α-subunit to exchange GDP (guanosine diphosphate) for GTP. This activation leads to dissociation of the G protein complex into the GTP-bound α-subunit and the βγ-subunit pair. Both the α-GTP and βγ subunits can then interact with downstream effectors, such as enzymes or ion channels, to propagate and amplify the signal within the cell.

The intrinsic GTPase activity of the α-subunit eventually hydrolyzes the bound GTP to GDP, which leads to re-association of the α and βγ subunits and termination of the signal. This cycle of activation and inactivation makes G proteins versatile signaling elements that can respond quickly and precisely to changing environmental conditions.

Defects in G protein-mediated signaling pathways have been implicated in various diseases, including cancer, neurological disorders, and cardiovascular diseases. Therefore, understanding the function and regulation of GTP-binding proteins is essential for developing targeted therapeutic strategies.

NAD (Nicotinamide Adenine Dinucleotide) is a coenzyme found in all living cells. It plays an essential role in cellular metabolism, particularly in redox reactions, where it acts as an electron carrier. NAD exists in two forms: NAD+, which accepts electrons and becomes reduced to NADH. This pairing of NAD+/NADH is involved in many fundamental biological processes such as generating energy in the form of ATP during cellular respiration, and serving as a critical cofactor for various enzymes that regulate cellular functions like DNA repair, gene expression, and cell death.

Maintaining optimal levels of NAD+/NADH is crucial for overall health and longevity, as it declines with age and in certain disease states. Therefore, strategies to boost NAD+ levels are being actively researched for their potential therapeutic benefits in various conditions such as aging, neurodegenerative disorders, and metabolic diseases.

In the context of medicine and pharmacology, "kinetics" refers to the study of how a drug moves throughout the body, including its absorption, distribution, metabolism, and excretion (often abbreviated as ADME). This field is called "pharmacokinetics."

1. Absorption: This is the process of a drug moving from its site of administration into the bloodstream. Factors such as the route of administration (e.g., oral, intravenous, etc.), formulation, and individual physiological differences can affect absorption.

2. Distribution: Once a drug is in the bloodstream, it gets distributed throughout the body to various tissues and organs. This process is influenced by factors like blood flow, protein binding, and lipid solubility of the drug.

3. Metabolism: Drugs are often chemically modified in the body, typically in the liver, through processes known as metabolism. These changes can lead to the formation of active or inactive metabolites, which may then be further distributed, excreted, or undergo additional metabolic transformations.

4. Excretion: This is the process by which drugs and their metabolites are eliminated from the body, primarily through the kidneys (urine) and the liver (bile).

Understanding the kinetics of a drug is crucial for determining its optimal dosing regimen, potential interactions with other medications or foods, and any necessary adjustments for special populations like pediatric or geriatric patients, or those with impaired renal or hepatic function.

Sequence homology, amino acid, refers to the similarity in the order of amino acids in a protein or a portion of a protein between two or more species. This similarity can be used to infer evolutionary relationships and functional similarities between proteins. The higher the degree of sequence homology, the more likely it is that the proteins are related and have similar functions. Sequence homology can be determined through various methods such as pairwise alignment or multiple sequence alignment, which compare the sequences and calculate a score based on the number and type of matching amino acids.

In the context of medical and biological sciences, a "binding site" refers to a specific location on a protein, molecule, or cell where another molecule can attach or bind. This binding interaction can lead to various functional changes in the original protein or molecule. The other molecule that binds to the binding site is often referred to as a ligand, which can be a small molecule, ion, or even another protein.

The binding between a ligand and its target binding site can be specific and selective, meaning that only certain ligands can bind to particular binding sites with high affinity. This specificity plays a crucial role in various biological processes, such as signal transduction, enzyme catalysis, or drug action.

In the case of drug development, understanding the location and properties of binding sites on target proteins is essential for designing drugs that can selectively bind to these sites and modulate protein function. This knowledge can help create more effective and safer therapeutic options for various diseases.

Protein conformation refers to the specific three-dimensional shape that a protein molecule assumes due to the spatial arrangement of its constituent amino acid residues and their associated chemical groups. This complex structure is determined by several factors, including covalent bonds (disulfide bridges), hydrogen bonds, van der Waals forces, and ionic bonds, which help stabilize the protein's unique conformation.

Protein conformations can be broadly classified into two categories: primary, secondary, tertiary, and quaternary structures. The primary structure represents the linear sequence of amino acids in a polypeptide chain. The secondary structure arises from local interactions between adjacent amino acid residues, leading to the formation of recurring motifs such as α-helices and β-sheets. Tertiary structure refers to the overall three-dimensional folding pattern of a single polypeptide chain, while quaternary structure describes the spatial arrangement of multiple folded polypeptide chains (subunits) that interact to form a functional protein complex.

Understanding protein conformation is crucial for elucidating protein function, as the specific three-dimensional shape of a protein directly influences its ability to interact with other molecules, such as ligands, nucleic acids, or other proteins. Any alterations in protein conformation due to genetic mutations, environmental factors, or chemical modifications can lead to loss of function, misfolding, aggregation, and disease states like neurodegenerative disorders and cancer.

Protein transport, in the context of cellular biology, refers to the process by which proteins are actively moved from one location to another within or between cells. This is a crucial mechanism for maintaining proper cell function and regulation.

Intracellular protein transport involves the movement of proteins within a single cell. Proteins can be transported across membranes (such as the nuclear envelope, endoplasmic reticulum, Golgi apparatus, or plasma membrane) via specialized transport systems like vesicles and transport channels.

Intercellular protein transport refers to the movement of proteins from one cell to another, often facilitated by exocytosis (release of proteins in vesicles) and endocytosis (uptake of extracellular substances via membrane-bound vesicles). This is essential for communication between cells, immune response, and other physiological processes.

It's important to note that any disruption in protein transport can lead to various diseases, including neurological disorders, cancer, and metabolic conditions.

HeLa cells are a type of immortalized cell line used in scientific research. They are derived from a cancer that developed in the cervical tissue of Henrietta Lacks, an African-American woman, in 1951. After her death, cells taken from her tumor were found to be capable of continuous division and growth in a laboratory setting, making them an invaluable resource for medical research.

HeLa cells have been used in a wide range of scientific studies, including research on cancer, viruses, genetics, and drug development. They were the first human cell line to be successfully cloned and are able to grow rapidly in culture, doubling their population every 20-24 hours. This has made them an essential tool for many areas of biomedical research.

It is important to note that while HeLa cells have been instrumental in numerous scientific breakthroughs, the story of their origin raises ethical questions about informed consent and the use of human tissue in research.

"Cells, cultured" is a medical term that refers to cells that have been removed from an organism and grown in controlled laboratory conditions outside of the body. This process is called cell culture and it allows scientists to study cells in a more controlled and accessible environment than they would have inside the body. Cultured cells can be derived from a variety of sources, including tissues, organs, or fluids from humans, animals, or cell lines that have been previously established in the laboratory.

Cell culture involves several steps, including isolation of the cells from the tissue, purification and characterization of the cells, and maintenance of the cells in appropriate growth conditions. The cells are typically grown in specialized media that contain nutrients, growth factors, and other components necessary for their survival and proliferation. Cultured cells can be used for a variety of purposes, including basic research, drug development and testing, and production of biological products such as vaccines and gene therapies.

It is important to note that cultured cells may behave differently than they do in the body, and results obtained from cell culture studies may not always translate directly to human physiology or disease. Therefore, it is essential to validate findings from cell culture experiments using additional models and ultimately in clinical trials involving human subjects.

Recombinant proteins are artificially created proteins produced through the use of recombinant DNA technology. This process involves combining DNA molecules from different sources to create a new set of genes that encode for a specific protein. The resulting recombinant protein can then be expressed, purified, and used for various applications in research, medicine, and industry.

Recombinant proteins are widely used in biomedical research to study protein function, structure, and interactions. They are also used in the development of diagnostic tests, vaccines, and therapeutic drugs. For example, recombinant insulin is a common treatment for diabetes, while recombinant human growth hormone is used to treat growth disorders.

The production of recombinant proteins typically involves the use of host cells, such as bacteria, yeast, or mammalian cells, which are engineered to express the desired protein. The host cells are transformed with a plasmid vector containing the gene of interest, along with regulatory elements that control its expression. Once the host cells are cultured and the protein is expressed, it can be purified using various chromatography techniques.

Overall, recombinant proteins have revolutionized many areas of biology and medicine, enabling researchers to study and manipulate proteins in ways that were previously impossible.

A dose-response relationship in the context of drugs refers to the changes in the effects or symptoms that occur as the dose of a drug is increased or decreased. Generally, as the dose of a drug is increased, the severity or intensity of its effects also increases. Conversely, as the dose is decreased, the effects of the drug become less severe or may disappear altogether.

The dose-response relationship is an important concept in pharmacology and toxicology because it helps to establish the safe and effective dosage range for a drug. By understanding how changes in the dose of a drug affect its therapeutic and adverse effects, healthcare providers can optimize treatment plans for their patients while minimizing the risk of harm.

The dose-response relationship is typically depicted as a curve that shows the relationship between the dose of a drug and its effect. The shape of the curve may vary depending on the drug and the specific effect being measured. Some drugs may have a steep dose-response curve, meaning that small changes in the dose can result in large differences in the effect. Other drugs may have a more gradual dose-response curve, where larger changes in the dose are needed to produce significant effects.

In addition to helping establish safe and effective dosages, the dose-response relationship is also used to evaluate the potential therapeutic benefits and risks of new drugs during clinical trials. By systematically testing different doses of a drug in controlled studies, researchers can identify the optimal dosage range for the drug and assess its safety and efficacy.

Recombinant fusion proteins are artificially created biomolecules that combine the functional domains or properties of two or more different proteins into a single protein entity. They are generated through recombinant DNA technology, where the genes encoding the desired protein domains are linked together and expressed as a single, chimeric gene in a host organism, such as bacteria, yeast, or mammalian cells.

The resulting fusion protein retains the functional properties of its individual constituent proteins, allowing for novel applications in research, diagnostics, and therapeutics. For instance, recombinant fusion proteins can be designed to enhance protein stability, solubility, or immunogenicity, making them valuable tools for studying protein-protein interactions, developing targeted therapies, or generating vaccines against infectious diseases or cancer.

Examples of recombinant fusion proteins include:

1. Etaglunatide (ABT-523): A soluble Fc fusion protein that combines the heavy chain fragment crystallizable region (Fc) of an immunoglobulin with the extracellular domain of the human interleukin-6 receptor (IL-6R). This fusion protein functions as a decoy receptor, neutralizing IL-6 and its downstream signaling pathways in rheumatoid arthritis.
2. Etanercept (Enbrel): A soluble TNF receptor p75 Fc fusion protein that binds to tumor necrosis factor-alpha (TNF-α) and inhibits its proinflammatory activity, making it a valuable therapeutic option for treating autoimmune diseases like rheumatoid arthritis, ankylosing spondylitis, and psoriasis.
3. Abatacept (Orencia): A fusion protein consisting of the extracellular domain of cytotoxic T-lymphocyte antigen 4 (CTLA-4) linked to the Fc region of an immunoglobulin, which downregulates T-cell activation and proliferation in autoimmune diseases like rheumatoid arthritis.
4. Belimumab (Benlysta): A monoclonal antibody that targets B-lymphocyte stimulator (BLyS) protein, preventing its interaction with the B-cell surface receptor and inhibiting B-cell activation in systemic lupus erythematosus (SLE).
5. Romiplostim (Nplate): A fusion protein consisting of a thrombopoietin receptor agonist peptide linked to an immunoglobulin Fc region, which stimulates platelet production in patients with chronic immune thrombocytopenia (ITP).
6. Darbepoetin alfa (Aranesp): A hyperglycosylated erythropoiesis-stimulating protein that functions as a longer-acting form of recombinant human erythropoietin, used to treat anemia in patients with chronic kidney disease or cancer.
7. Palivizumab (Synagis): A monoclonal antibody directed against the F protein of respiratory syncytial virus (RSV), which prevents RSV infection and is administered prophylactically to high-risk infants during the RSV season.
8. Ranibizumab (Lucentis): A recombinant humanized monoclonal antibody fragment that binds and inhibits vascular endothelial growth factor A (VEGF-A), used in the treatment of age-related macular degeneration, diabetic retinopathy, and other ocular disorders.
9. Cetuximab (Erbitux): A chimeric monoclonal antibody that binds to epidermal growth factor receptor (EGFR), used in the treatment of colorectal cancer and head and neck squamous cell carcinoma.
10. Adalimumab (Humira): A fully humanized monoclonal antibody that targets tumor necrosis factor-alpha (TNF-α), used in the treatment of various inflammatory diseases, including rheumatoid arthritis, psoriasis, and Crohn's disease.
11. Bevacizumab (Avastin): A recombinant humanized monoclonal antibody that binds to VEGF-A, used in the treatment of various cancers, including colorectal, lung, breast, and kidney cancer.
12. Trastuzumab (Herceptin): A humanized monoclonal antibody that targets HER2/neu receptor, used in the treatment of breast cancer.
13. Rituximab (Rituxan): A chimeric monoclonal antibody that binds to CD20 antigen on B cells, used in the treatment of non-Hodgkin's lymphoma and rheumatoid arthritis.
14. Palivizumab (Synagis): A humanized monoclonal antibody that binds to the F protein of respiratory syncytial virus, used in the prevention of respiratory syncytial virus infection in high-risk infants.
15. Infliximab (Remicade): A chimeric monoclonal antibody that targets TNF-α, used in the treatment of various inflammatory diseases, including Crohn's disease, ulcerative colitis, rheumatoid arthritis, and ankylosing spondylitis.
16. Natalizumab (Tysabri): A humanized monoclonal antibody that binds to α4β1 integrin, used in the treatment of multiple sclerosis and Crohn's disease.
17. Adalimumab (Humira): A fully human monoclonal antibody that targets TNF-α, used in the treatment of various inflammatory diseases, including rheumatoid arthritis, psoriatic arthritis, ankylosing spondylitis, Crohn's disease, and ulcerative colitis.
18. Golimumab (Simponi): A fully human monoclonal antibody that targets TNF-α, used in the treatment of rheumatoid arthritis, psoriatic arthritis, ankylosing spondylitis, and ulcerative colitis.
19. Certolizumab pegol (Cimzia): A PEGylated Fab' fragment of a humanized monoclonal antibody that targets TNF-α, used in the treatment of rheumatoid arthritis, psoriatic arthritis, ankylosing spondylitis, and Crohn's disease.
20. Ustekinumab (Stelara): A fully human monoclonal antibody that targets IL-12 and IL-23, used in the treatment of psoriasis, psoriatic arthritis, and Crohn's disease.
21. Secukinumab (Cosentyx): A fully human monoclonal antibody that targets IL-17A, used in the treatment of psoriasis, psoriatic arthritis, and ankylosing spondylitis.
22. Ixekizumab (Taltz): A fully human monoclonal antibody that targets IL-17A, used in the treatment of psoriasis and psoriatic arthritis.
23. Brodalumab (Siliq): A fully human monoclonal antibody that targets IL-17 receptor A, used in the treatment of psoriasis.
24. Sarilumab (Kevzara): A fully human monoclonal antibody that targets the IL-6 receptor, used in the treatment of rheumatoid arthritis.
25. Tocilizumab (Actemra): A humanized monoclonal antibody that targets the IL-6 receptor, used in the treatment of rheumatoid arthritis, systemic juvenile idiopathic arthritis, polyarticular juvenile idiopathic arthritis, giant cell arteritis, and chimeric antigen receptor T-cell-induced cytokine release syndrome.
26. Siltuximab (Sylvant): A chimeric monoclonal antibody that targets IL-6, used in the treatment of multicentric Castleman disease.
27. Satralizumab (Enspryng): A humanized monoclonal antibody that targets IL-6 receptor alpha, used in the treatment of neuromyelitis optica spectrum disorder.
28. Sirukumab (Plivensia): A human monoclonal antibody that targets IL-6, used in the treatment

RhoA (Ras Homolog Family Member A) is a small GTPase protein that acts as a molecular switch, cycling between an inactive GDP-bound state and an active GTP-bound state. It plays a crucial role in regulating various cellular processes such as actin cytoskeleton organization, gene expression, cell cycle progression, and cell migration.

RhoA GTP-binding protein becomes activated when it binds to GTP, and this activation leads to the recruitment of downstream effectors that mediate its functions. The activity of RhoA is tightly regulated by several proteins, including guanine nucleotide exchange factors (GEFs) that promote the exchange of GDP for GTP, GTPase-activating proteins (GAPs) that stimulate the intrinsic GTPase activity of RhoA to hydrolyze GTP to GDP and return it to an inactive state, and guanine nucleotide dissociation inhibitors (GDIs) that sequester RhoA in the cytoplasm and prevent its association with the membrane.

Mutations or dysregulation of RhoA GTP-binding protein have been implicated in various human diseases, including cancer, neurological disorders, and cardiovascular diseases.

A Structure-Activity Relationship (SAR) in the context of medicinal chemistry and pharmacology refers to the relationship between the chemical structure of a drug or molecule and its biological activity or effect on a target protein, cell, or organism. SAR studies aim to identify patterns and correlations between structural features of a compound and its ability to interact with a specific biological target, leading to a desired therapeutic response or undesired side effects.

By analyzing the SAR, researchers can optimize the chemical structure of lead compounds to enhance their potency, selectivity, safety, and pharmacokinetic properties, ultimately guiding the design and development of novel drugs with improved efficacy and reduced toxicity.

Actin is a type of protein that forms part of the contractile apparatus in muscle cells, and is also found in various other cell types. It is a globular protein that polymerizes to form long filaments, which are important for many cellular processes such as cell division, cell motility, and the maintenance of cell shape. In muscle cells, actin filaments interact with another type of protein called myosin to enable muscle contraction. Actins can be further divided into different subtypes, including alpha-actin, beta-actin, and gamma-actin, which have distinct functions and expression patterns in the body.

Bacteria are single-celled microorganisms that are among the earliest known life forms on Earth. They are typically characterized as having a cell wall and no membrane-bound organelles. The majority of bacteria have a prokaryotic organization, meaning they lack a nucleus and other membrane-bound organelles.

Bacteria exist in diverse environments and can be found in every habitat on Earth, including soil, water, and the bodies of plants and animals. Some bacteria are beneficial to their hosts, while others can cause disease. Beneficial bacteria play important roles in processes such as digestion, nitrogen fixation, and biogeochemical cycling.

Bacteria reproduce asexually through binary fission or budding, and some species can also exchange genetic material through conjugation. They have a wide range of metabolic capabilities, with many using organic compounds as their source of energy, while others are capable of photosynthesis or chemosynthesis.

Bacteria are highly adaptable and can evolve rapidly in response to environmental changes. This has led to the development of antibiotic resistance in some species, which poses a significant public health challenge. Understanding the biology and behavior of bacteria is essential for developing strategies to prevent and treat bacterial infections and diseases.

Cricetinae is a subfamily of rodents that includes hamsters, gerbils, and relatives. These small mammals are characterized by having short limbs, compact bodies, and cheek pouches for storing food. They are native to various parts of the world, particularly in Europe, Asia, and Africa. Some species are popular pets due to their small size, easy care, and friendly nature. In a medical context, understanding the biology and behavior of Cricetinae species can be important for individuals who keep them as pets or for researchers studying their physiology.

Scorpion venoms are complex mixtures of neurotoxins, enzymes, and other bioactive molecules that are produced by the venom glands of scorpions. These venoms are primarily used for prey immobilization and defense. The neurotoxins found in scorpion venoms can cause a variety of symptoms in humans, including pain, swelling, numbness, and in severe cases, respiratory failure and death.

Scorpion venoms are being studied for their potential medical applications, such as in the development of new pain medications and insecticides. Additionally, some components of scorpion venom have been found to have antimicrobial properties and may be useful in the development of new antibiotics.

Cell surface receptors, also known as membrane receptors, are proteins located on the cell membrane that bind to specific molecules outside the cell, known as ligands. These receptors play a crucial role in signal transduction, which is the process of converting an extracellular signal into an intracellular response.

Cell surface receptors can be classified into several categories based on their structure and mechanism of action, including:

1. Ion channel receptors: These receptors contain a pore that opens to allow ions to flow across the cell membrane when they bind to their ligands. This ion flux can directly activate or inhibit various cellular processes.
2. G protein-coupled receptors (GPCRs): These receptors consist of seven transmembrane domains and are associated with heterotrimeric G proteins that modulate intracellular signaling pathways upon ligand binding.
3. Enzyme-linked receptors: These receptors possess an intrinsic enzymatic activity or are linked to an enzyme, which becomes activated when the receptor binds to its ligand. This activation can lead to the initiation of various signaling cascades within the cell.
4. Receptor tyrosine kinases (RTKs): These receptors contain intracellular tyrosine kinase domains that become activated upon ligand binding, leading to the phosphorylation and activation of downstream signaling molecules.
5. Integrins: These receptors are transmembrane proteins that mediate cell-cell or cell-matrix interactions by binding to extracellular matrix proteins or counter-receptors on adjacent cells. They play essential roles in cell adhesion, migration, and survival.

Cell surface receptors are involved in various physiological processes, including neurotransmission, hormone signaling, immune response, and cell growth and differentiation. Dysregulation of these receptors can contribute to the development of numerous diseases, such as cancer, diabetes, and neurological disorders.

'Clostridium difficile' (also known as 'C. difficile' or 'C. diff') is a type of Gram-positive, spore-forming bacterium that can be found in the environment, including in soil, water, and human and animal feces. It is a common cause of healthcare-associated infections, particularly in individuals who have recently received antibiotics or have other underlying health conditions that weaken their immune system.

C. difficile produces toxins that can cause a range of symptoms, from mild diarrhea to severe colitis (inflammation of the colon) and potentially life-threatening complications such as sepsis and toxic megacolon. The most common toxins produced by C. difficile are called TcdA and TcdB, which damage the lining of the intestine and cause inflammation.

C. difficile infections (CDIs) can be difficult to treat, particularly in severe cases or in patients who have recurrent infections. Treatment typically involves discontinuing any unnecessary antibiotics, if possible, and administering specific antibiotics that are effective against C. difficile, such as metronidazole, vancomycin, or fidaxomicin. In some cases, fecal microbiota transplantation (FMT) may be recommended as a last resort for patients with recurrent or severe CDIs who have not responded to other treatments.

Preventing the spread of C. difficile is critical in healthcare settings, and includes measures such as hand hygiene, contact precautions, environmental cleaning, and antibiotic stewardship programs that promote the appropriate use of antibiotics.

'Cercopithecus aethiops' is the scientific name for the monkey species more commonly known as the green monkey. It belongs to the family Cercopithecidae and is native to western Africa. The green monkey is omnivorous, with a diet that includes fruits, nuts, seeds, insects, and small vertebrates. They are known for their distinctive greenish-brown fur and long tail. Green monkeys are also important animal models in biomedical research due to their susceptibility to certain diseases, such as SIV (simian immunodeficiency virus), which is closely related to HIV.

Endocytosis is the process by which cells absorb substances from their external environment by engulfing them in membrane-bound structures, resulting in the formation of intracellular vesicles. This mechanism allows cells to take up large molecules, such as proteins and lipids, as well as small particles, like bacteria and viruses. There are two main types of endocytosis: phagocytosis (cell eating) and pinocytosis (cell drinking). Phagocytosis involves the engulfment of solid particles, while pinocytosis deals with the uptake of fluids and dissolved substances. Other specialized forms of endocytosis include receptor-mediated endocytosis and caveolae-mediated endocytosis, which allow for the specific internalization of molecules through the interaction with cell surface receptors.

Mycotoxins are toxic secondary metabolites produced by certain types of fungi (molds) that can contaminate food and feed crops, both during growth and storage. These toxins can cause a variety of adverse health effects in humans and animals, ranging from acute poisoning to long-term chronic exposure, which may lead to immune suppression, cancer, and other diseases. Mycotoxin-producing fungi mainly belong to the genera Aspergillus, Penicillium, Fusarium, and Alternaria. Common mycotoxins include aflatoxins, ochratoxins, fumonisins, zearalenone, patulin, and citrinin. The presence of mycotoxins in food and feed is a significant public health concern and requires stringent monitoring and control measures to ensure safety.

Substrate specificity in the context of medical biochemistry and enzymology refers to the ability of an enzyme to selectively bind and catalyze a chemical reaction with a particular substrate (or a group of similar substrates) while discriminating against other molecules that are not substrates. This specificity arises from the three-dimensional structure of the enzyme, which has evolved to match the shape, charge distribution, and functional groups of its physiological substrate(s).

Substrate specificity is a fundamental property of enzymes that enables them to carry out highly selective chemical transformations in the complex cellular environment. The active site of an enzyme, where the catalysis takes place, has a unique conformation that complements the shape and charge distribution of its substrate(s). This ensures efficient recognition, binding, and conversion of the substrate into the desired product while minimizing unwanted side reactions with other molecules.

Substrate specificity can be categorized as:

1. Absolute specificity: An enzyme that can only act on a single substrate or a very narrow group of structurally related substrates, showing no activity towards any other molecule.
2. Group specificity: An enzyme that prefers to act on a particular functional group or class of compounds but can still accommodate minor structural variations within the substrate.
3. Broad or promiscuous specificity: An enzyme that can act on a wide range of structurally diverse substrates, albeit with varying catalytic efficiencies.

Understanding substrate specificity is crucial for elucidating enzymatic mechanisms, designing drugs that target specific enzymes or pathways, and developing biotechnological applications that rely on the controlled manipulation of enzyme activities.

A base sequence in the context of molecular biology refers to the specific order of nucleotides in a DNA or RNA molecule. In DNA, these nucleotides are adenine (A), guanine (G), cytosine (C), and thymine (T). In RNA, uracil (U) takes the place of thymine. The base sequence contains genetic information that is transcribed into RNA and ultimately translated into proteins. It is the exact order of these bases that determines the genetic code and thus the function of the DNA or RNA molecule.

CHO cells, or Chinese Hamster Ovary cells, are a type of immortalized cell line that are commonly used in scientific research and biotechnology. They were originally derived from the ovaries of a female Chinese hamster (Cricetulus griseus) in the 1950s.

CHO cells have several characteristics that make them useful for laboratory experiments. They can grow and divide indefinitely under appropriate conditions, which allows researchers to culture large quantities of them for study. Additionally, CHO cells are capable of expressing high levels of recombinant proteins, making them a popular choice for the production of therapeutic drugs, vaccines, and other biologics.

In particular, CHO cells have become a workhorse in the field of biotherapeutics, with many approved monoclonal antibody-based therapies being produced using these cells. The ability to genetically modify CHO cells through various methods has further expanded their utility in research and industrial applications.

It is important to note that while CHO cells are widely used in scientific research, they may not always accurately represent human cell behavior or respond to drugs and other compounds in the same way as human cells do. Therefore, results obtained using CHO cells should be validated in more relevant systems when possible.

A lipid bilayer is a thin membrane made up of two layers of lipid molecules, primarily phospholipids. The hydrophilic (water-loving) heads of the lipids face outwards, coming into contact with watery environments on both sides, while the hydrophobic (water-fearing) tails point inward, away from the aqueous surroundings. This unique structure allows lipid bilayers to form a stable barrier that controls the movement of molecules and ions in and out of cells and organelles, thus playing a crucial role in maintaining cellular compartmentalization and homeostasis.

Cyclic adenosine monophosphate (cAMP) is a key secondary messenger in many biological processes, including the regulation of metabolism, gene expression, and cellular excitability. It is synthesized from adenosine triphosphate (ATP) by the enzyme adenylyl cyclase and is degraded by the enzyme phosphodiesterase.

In the body, cAMP plays a crucial role in mediating the effects of hormones and neurotransmitters on target cells. For example, when a hormone binds to its receptor on the surface of a cell, it can activate a G protein, which in turn activates adenylyl cyclase to produce cAMP. The increased levels of cAMP then activate various effector proteins, such as protein kinases, which go on to regulate various cellular processes.

Overall, the regulation of cAMP levels is critical for maintaining proper cellular function and homeostasis, and abnormalities in cAMP signaling have been implicated in a variety of diseases, including cancer, diabetes, and neurological disorders.

I believe there may be some confusion in your question. "Rabbits" is a common name used to refer to the Lagomorpha species, particularly members of the family Leporidae. They are small mammals known for their long ears, strong legs, and quick reproduction.

However, if you're referring to "rabbits" in a medical context, there is a term called "rabbit syndrome," which is a rare movement disorder characterized by repetitive, involuntary movements of the fingers, resembling those of a rabbit chewing. It is also known as "finger-chewing chorea." This condition is usually associated with certain medications, particularly antipsychotics, and typically resolves when the medication is stopped or adjusted.

Signal transduction is the process by which a cell converts an extracellular signal, such as a hormone or neurotransmitter, into an intracellular response. This involves a series of molecular events that transmit the signal from the cell surface to the interior of the cell, ultimately resulting in changes in gene expression, protein activity, or metabolism.

The process typically begins with the binding of the extracellular signal to a receptor located on the cell membrane. This binding event activates the receptor, which then triggers a cascade of intracellular signaling molecules, such as second messengers, protein kinases, and ion channels. These molecules amplify and propagate the signal, ultimately leading to the activation or inhibition of specific cellular responses.

Signal transduction pathways are highly regulated and can be modulated by various factors, including other signaling molecules, post-translational modifications, and feedback mechanisms. Dysregulation of these pathways has been implicated in a variety of diseases, including cancer, diabetes, and neurological disorders.

Liposomes are artificially prepared, small, spherical vesicles composed of one or more lipid bilayers that enclose an aqueous compartment. They can encapsulate both hydrophilic and hydrophobic drugs, making them useful for drug delivery applications in the medical field. The lipid bilayer structure of liposomes is similar to that of biological membranes, which allows them to merge with and deliver their contents into cells. This property makes liposomes a valuable tool in delivering drugs directly to targeted sites within the body, improving drug efficacy while minimizing side effects.

In genetics, sequence alignment is the process of arranging two or more DNA, RNA, or protein sequences to identify regions of similarity or homology between them. This is often done using computational methods to compare the nucleotide or amino acid sequences and identify matching patterns, which can provide insight into evolutionary relationships, functional domains, or potential genetic disorders. The alignment process typically involves adjusting gaps and mismatches in the sequences to maximize the similarity between them, resulting in an aligned sequence that can be visually represented and analyzed.

Peptides are short chains of amino acid residues linked by covalent bonds, known as peptide bonds. They are formed when two or more amino acids are joined together through a condensation reaction, which results in the elimination of a water molecule and the formation of an amide bond between the carboxyl group of one amino acid and the amino group of another.

Peptides can vary in length from two to about fifty amino acids, and they are often classified based on their size. For example, dipeptides contain two amino acids, tripeptides contain three, and so on. Oligopeptides typically contain up to ten amino acids, while polypeptides can contain dozens or even hundreds of amino acids.

Peptides play many important roles in the body, including serving as hormones, neurotransmitters, enzymes, and antibiotics. They are also used in medical research and therapeutic applications, such as drug delivery and tissue engineering.

Lipopolysaccharides (LPS) are large molecules found in the outer membrane of Gram-negative bacteria. They consist of a hydrophilic polysaccharide called the O-antigen, a core oligosaccharide, and a lipid portion known as Lipid A. The Lipid A component is responsible for the endotoxic activity of LPS, which can trigger a powerful immune response in animals, including humans. This response can lead to symptoms such as fever, inflammation, and septic shock, especially when large amounts of LPS are introduced into the bloodstream.

"Pseudomonas aeruginosa" is a medically important, gram-negative, rod-shaped bacterium that is widely found in the environment, such as in soil, water, and on plants. It's an opportunistic pathogen, meaning it usually doesn't cause infection in healthy individuals but can cause severe and sometimes life-threatening infections in people with weakened immune systems, burns, or chronic lung diseases like cystic fibrosis.

P. aeruginosa is known for its remarkable ability to resist many antibiotics and disinfectants due to its intrinsic resistance mechanisms and the acquisition of additional resistance determinants. It can cause various types of infections, including respiratory tract infections, urinary tract infections, gastrointestinal infections, dermatitis, and severe bloodstream infections known as sepsis.

The bacterium produces a variety of virulence factors that contribute to its pathogenicity, such as exotoxins, proteases, and pigments like pyocyanin and pyoverdine, which aid in iron acquisition and help the organism evade host immune responses. Effective infection control measures, appropriate use of antibiotics, and close monitoring of high-risk patients are crucial for managing P. aeruginosa infections.

Secondary protein structure refers to the local spatial arrangement of amino acid chains in a protein, typically described as regular repeating patterns held together by hydrogen bonds. The two most common types of secondary structures are the alpha-helix (α-helix) and the beta-pleated sheet (β-sheet). In an α-helix, the polypeptide chain twists around itself in a helical shape, with each backbone atom forming a hydrogen bond with the fourth amino acid residue along the chain. This forms a rigid rod-like structure that is resistant to bending or twisting forces. In β-sheets, adjacent segments of the polypeptide chain run parallel or antiparallel to each other and are connected by hydrogen bonds, forming a pleated sheet-like arrangement. These secondary structures provide the foundation for the formation of tertiary and quaternary protein structures, which determine the overall three-dimensional shape and function of the protein.

A mutation is a permanent change in the DNA sequence of an organism's genome. Mutations can occur spontaneously or be caused by environmental factors such as exposure to radiation, chemicals, or viruses. They may have various effects on the organism, ranging from benign to harmful, depending on where they occur and whether they alter the function of essential proteins. In some cases, mutations can increase an individual's susceptibility to certain diseases or disorders, while in others, they may confer a survival advantage. Mutations are the driving force behind evolution, as they introduce new genetic variability into populations, which can then be acted upon by natural selection.

Neuromuscular agents are drugs or substances that affect the function of the neuromuscular junction, which is the site where nerve impulses are transmitted to muscles. These agents can either enhance or inhibit the transmission of signals across the neuromuscular junction, leading to a variety of effects on muscle tone and activity.

Neuromuscular blocking agents (NMBAs) are a type of neuromuscular agent that is commonly used in anesthesia and critical care settings to induce paralysis during intubation or mechanical ventilation. NMBAs can be classified into two main categories: depolarizing and non-depolarizing agents.

Depolarizing NMBAs, such as succinylcholine, work by activating the nicotinic acetylcholine receptors at the neuromuscular junction, causing muscle contraction followed by paralysis. Non-depolarizing NMBAs, such as rocuronium and vecuronium, block the activation of these receptors, preventing muscle contraction and leading to paralysis.

Other types of neuromuscular agents include cholinesterase inhibitors, which increase the levels of acetylcholine at the neuromuscular junction and can be used to reverse the effects of NMBAs, and botulinum toxin, which is a potent neurotoxin that inhibits the release of acetylcholine from nerve terminals and is used in the treatment of various neurological disorders.

Membrane proteins are a type of protein that are embedded in the lipid bilayer of biological membranes, such as the plasma membrane of cells or the inner membrane of mitochondria. These proteins play crucial roles in various cellular processes, including:

1. Cell-cell recognition and signaling
2. Transport of molecules across the membrane (selective permeability)
3. Enzymatic reactions at the membrane surface
4. Energy transduction and conversion
5. Mechanosensation and signal transduction

Membrane proteins can be classified into two main categories: integral membrane proteins, which are permanently associated with the lipid bilayer, and peripheral membrane proteins, which are temporarily or loosely attached to the membrane surface. Integral membrane proteins can further be divided into three subcategories based on their topology:

1. Transmembrane proteins, which span the entire width of the lipid bilayer with one or more alpha-helices or beta-barrels.
2. Lipid-anchored proteins, which are covalently attached to lipids in the membrane via a glycosylphosphatidylinositol (GPI) anchor or other lipid modifications.
3. Monotopic proteins, which are partially embedded in the membrane and have one or more domains exposed to either side of the bilayer.

Membrane proteins are essential for maintaining cellular homeostasis and are targets for various therapeutic interventions, including drug development and gene therapy. However, their structural complexity and hydrophobicity make them challenging to study using traditional biochemical methods, requiring specialized techniques such as X-ray crystallography, nuclear magnetic resonance (NMR) spectroscopy, and single-particle cryo-electron microscopy (cryo-EM).

Site-directed mutagenesis is a molecular biology technique used to introduce specific and targeted changes to a specific DNA sequence. This process involves creating a new variant of a gene or a specific region of interest within a DNA molecule by introducing a planned, deliberate change, or mutation, at a predetermined site within the DNA sequence.

The methodology typically involves the use of molecular tools such as PCR (polymerase chain reaction), restriction enzymes, and/or ligases to introduce the desired mutation(s) into a plasmid or other vector containing the target DNA sequence. The resulting modified DNA molecule can then be used to transform host cells, allowing for the production of large quantities of the mutated gene or protein for further study.

Site-directed mutagenesis is a valuable tool in basic research, drug discovery, and biotechnology applications where specific changes to a DNA sequence are required to understand gene function, investigate protein structure/function relationships, or engineer novel biological properties into existing genes or proteins.

Enzyme activation refers to the process by which an enzyme becomes biologically active and capable of carrying out its specific chemical or biological reaction. This is often achieved through various post-translational modifications, such as proteolytic cleavage, phosphorylation, or addition of cofactors or prosthetic groups to the enzyme molecule. These modifications can change the conformation or structure of the enzyme, exposing or creating a binding site for the substrate and allowing the enzymatic reaction to occur.

For example, in the case of proteolytic cleavage, an inactive precursor enzyme, known as a zymogen, is cleaved into its active form by a specific protease. This is seen in enzymes such as trypsin and chymotrypsin, which are initially produced in the pancreas as inactive precursors called trypsinogen and chymotrypsinogen, respectively. Once they reach the small intestine, they are activated by enteropeptidase, a protease that cleaves a specific peptide bond, releasing the active enzyme.

Phosphorylation is another common mechanism of enzyme activation, where a phosphate group is added to a specific serine, threonine, or tyrosine residue on the enzyme by a protein kinase. This modification can alter the conformation of the enzyme and create a binding site for the substrate, allowing the enzymatic reaction to occur.

Enzyme activation is a crucial process in many biological pathways, as it allows for precise control over when and where specific reactions take place. It also provides a mechanism for regulating enzyme activity in response to various signals and stimuli, such as hormones, neurotransmitters, or changes in the intracellular environment.

Hydrogen-ion concentration, also known as pH, is a measure of the acidity or basicity of a solution. It is defined as the negative logarithm (to the base 10) of the hydrogen ion activity in a solution. The standard unit of measurement is the pH unit. A pH of 7 is neutral, less than 7 is acidic, and greater than 7 is basic.

In medical terms, hydrogen-ion concentration is important for maintaining homeostasis within the body. For example, in the stomach, a high hydrogen-ion concentration (low pH) is necessary for the digestion of food. However, in other parts of the body such as blood, a high hydrogen-ion concentration can be harmful and lead to acidosis. Conversely, a low hydrogen-ion concentration (high pH) in the blood can lead to alkalosis. Both acidosis and alkalosis can have serious consequences on various organ systems if not corrected.

I believe there may be some confusion in your question as "scorpions" are not a medical term, but instead refer to a type of arachnid. If you're asking about a medical condition that might involve scorpions, then perhaps you're referring to "scorpion stings."

Scorpion stings occur when a scorpion uses its venomous stinger to inject venom into another animal or human. The effects of a scorpion sting can vary greatly depending on the species of scorpion and the amount of venom injected, but generally, they can cause localized pain, swelling, and redness at the site of the sting. In more severe cases, symptoms such as numbness, difficulty breathing, muscle twitching, or convulsions may occur. Some species of scorpions have venom that can be life-threatening to humans, especially in children, the elderly, and those with compromised immune systems.

If you are looking for information on a specific medical condition or term, please provide more details so I can give you a more accurate answer.

X-ray crystallography is a technique used in structural biology to determine the three-dimensional arrangement of atoms in a crystal lattice. In this method, a beam of X-rays is directed at a crystal and diffracts, or spreads out, into a pattern of spots called reflections. The intensity and angle of each reflection are measured and used to create an electron density map, which reveals the position and type of atoms in the crystal. This information can be used to determine the molecular structure of a compound, including its shape, size, and chemical bonds. X-ray crystallography is a powerful tool for understanding the structure and function of biological macromolecules such as proteins and nucleic acids.

Ricin is defined as a highly toxic protein that is derived from the seeds of the castor oil plant (Ricinus communis). It can be produced as a white, powdery substance or a mistable aerosol. Ricin works by getting inside cells and preventing them from making the proteins they need. Without protein, cells die. Eventually, this can cause organ failure and death.

It is not easily inhaled or absorbed through the skin, but if ingested or injected, it can be lethal in very small amounts. There is no antidote for ricin poisoning - treatment consists of supportive care. Ricin has been used as a bioterrorism agent in the past and continues to be a concern due to its relative ease of production and potential high toxicity.

Molecular cloning is a laboratory technique used to create multiple copies of a specific DNA sequence. This process involves several steps:

1. Isolation: The first step in molecular cloning is to isolate the DNA sequence of interest from the rest of the genomic DNA. This can be done using various methods such as PCR (polymerase chain reaction), restriction enzymes, or hybridization.
2. Vector construction: Once the DNA sequence of interest has been isolated, it must be inserted into a vector, which is a small circular DNA molecule that can replicate independently in a host cell. Common vectors used in molecular cloning include plasmids and phages.
3. Transformation: The constructed vector is then introduced into a host cell, usually a bacterial or yeast cell, through a process called transformation. This can be done using various methods such as electroporation or chemical transformation.
4. Selection: After transformation, the host cells are grown in selective media that allow only those cells containing the vector to grow. This ensures that the DNA sequence of interest has been successfully cloned into the vector.
5. Amplification: Once the host cells have been selected, they can be grown in large quantities to amplify the number of copies of the cloned DNA sequence.

Molecular cloning is a powerful tool in molecular biology and has numerous applications, including the production of recombinant proteins, gene therapy, functional analysis of genes, and genetic engineering.

In the field of medicine, "time factors" refer to the duration of symptoms or time elapsed since the onset of a medical condition, which can have significant implications for diagnosis and treatment. Understanding time factors is crucial in determining the progression of a disease, evaluating the effectiveness of treatments, and making critical decisions regarding patient care.

For example, in stroke management, "time is brain," meaning that rapid intervention within a specific time frame (usually within 4.5 hours) is essential to administering tissue plasminogen activator (tPA), a clot-busting drug that can minimize brain damage and improve patient outcomes. Similarly, in trauma care, the "golden hour" concept emphasizes the importance of providing definitive care within the first 60 minutes after injury to increase survival rates and reduce morbidity.

Time factors also play a role in monitoring the progression of chronic conditions like diabetes or heart disease, where regular follow-ups and assessments help determine appropriate treatment adjustments and prevent complications. In infectious diseases, time factors are crucial for initiating antibiotic therapy and identifying potential outbreaks to control their spread.

Overall, "time factors" encompass the significance of recognizing and acting promptly in various medical scenarios to optimize patient outcomes and provide effective care.

Neurotoxins are substances that are poisonous or destructive to nerve cells (neurons) and the nervous system. They can cause damage by destroying neurons, disrupting communication between neurons, or interfering with the normal functioning of the nervous system. Neurotoxins can be produced naturally by certain organisms, such as bacteria, plants, and animals, or they can be synthetic compounds created in a laboratory. Examples of neurotoxins include botulinum toxin (found in botulism), tetrodotoxin (found in pufferfish), and heavy metals like lead and mercury. Neurotoxic effects can range from mild symptoms such as headaches, muscle weakness, and tremors, to more severe symptoms such as paralysis, seizures, and cognitive impairment. Long-term exposure to neurotoxins can lead to chronic neurological conditions and other health problems.

'Clostridium botulinum' is a gram-positive, rod-shaped, anaerobic bacteria that produces one or more neurotoxins known as botulinum toxins. These toxins are among the most potent naturally occurring biological poisons and can cause a severe form of food poisoning called botulism in humans and animals. Botulism is characterized by symmetrical descending flaccid paralysis, which can lead to respiratory and cardiovascular failure, and ultimately death if not treated promptly.

The bacteria are widely distributed in nature, particularly in soil, sediments, and the intestinal tracts of some animals. They can form spores that are highly resistant to heat, chemicals, and other environmental stresses, allowing them to survive for long periods in adverse conditions. The spores can germinate and produce vegetative cells and toxins when they encounter favorable conditions, such as anaerobic environments with appropriate nutrients.

Human botulism can occur through three main routes of exposure: foodborne, wound, and infant botulism. Foodborne botulism results from consuming contaminated food containing preformed toxins, while wound botulism occurs when the bacteria infect a wound and produce toxins in situ. Infant botulism is caused by the ingestion of spores that colonize the intestines and produce toxins, mainly affecting infants under one year of age.

Prevention measures include proper food handling, storage, and preparation practices, such as cooking and canning foods at appropriate temperatures and for sufficient durations. Wound care and prompt medical attention are crucial in preventing wound botulism. Vaccines and antitoxins are available for prophylaxis and treatment of botulism in high-risk individuals or in cases of confirmed exposure.

BALB/c is an inbred strain of laboratory mouse that is widely used in biomedical research. The strain was developed at the Institute of Cancer Research in London by Henry Baldwin and his colleagues in the 1920s, and it has since become one of the most commonly used inbred strains in the world.

BALB/c mice are characterized by their black coat color, which is determined by a recessive allele at the tyrosinase locus. They are also known for their docile and friendly temperament, making them easy to handle and work with in the laboratory.

One of the key features of BALB/c mice that makes them useful for research is their susceptibility to certain types of tumors and immune responses. For example, they are highly susceptible to developing mammary tumors, which can be induced by chemical carcinogens or viral infection. They also have a strong Th2-biased immune response, which makes them useful models for studying allergic diseases and asthma.

BALB/c mice are also commonly used in studies of genetics, neuroscience, behavior, and infectious diseases. Because they are an inbred strain, they have a uniform genetic background, which makes it easier to control for genetic factors in experiments. Additionally, because they have been bred in the laboratory for many generations, they are highly standardized and reproducible, making them ideal subjects for scientific research.

'Bacillus thuringiensis' (Bt) is a gram-positive, soil-dwelling bacterium that produces crystalline parasporal proteins during sporulation. These proteins are insecticidal and have the ability to kill certain insects when ingested. Different strains of Bt produce different types of insecticidal proteins, allowing them to target specific insect pests.

Bt is widely used in organic farming and integrated pest management programs as a natural alternative to chemical pesticides. It can be applied as a spray or incorporated into the genetic material of crops through biotechnology, producing transgenic plants known as Bt crops. These crops express the insecticidal proteins and protect themselves from specific pests, reducing the need for external applications of Bt formulations.

Bt is considered safe for humans, animals, and non-target organisms when used properly, as the parasporal proteins are not toxic to them. However, misuse or overreliance on Bt can lead to resistance development in target pests, reducing its effectiveness.

Spider venoms are complex mixtures of bioactive compounds produced by the specialized glands of spiders. These venoms are primarily used for prey immobilization and defense. They contain a variety of molecules such as neurotoxins, proteases, peptides, and other biologically active substances. Different spider species have unique venom compositions, which can cause different reactions when they bite or come into contact with humans or other animals. Some spider venoms can cause mild symptoms like pain and swelling, while others can lead to more severe reactions such as tissue necrosis or even death in extreme cases.

Cnidarian venoms are toxic substances produced by members of the phylum Cnidaria, which includes jellyfish, sea anemones, corals, and hydroids. These venoms are primarily contained in specialized cells called cnidocytes or nematocysts, which are found in the tentacles of these animals. When a cnidarian comes into contact with prey or a potential threat, the cnidocytes discharge, injecting the venom into the target through a hollow tubule.

Cnidarian venoms are complex mixtures of bioactive molecules, including proteins, peptides, and small organic compounds. The composition of these venoms can vary significantly between different cnidarian species, as well as between different life stages or sexes of the same species. Some cnidarian venoms primarily serve a defensive function, causing pain or other unpleasant symptoms in potential predators, while others have a more offensive role, helping to immobilize prey before consumption.

The effects of cnidarian venoms on humans can range from mild irritation and stinging sensations to severe pain, swelling, and allergic reactions. In some cases, cnidarian envenomations can lead to more serious complications, such as respiratory distress, cardiac arrhythmias, or even death, particularly in individuals with underlying health conditions or allergies to the venom.

Research on cnidarian venoms has led to important insights into the biochemistry and molecular mechanisms of pain, inflammation, and neurotoxicity, as well as the development of new therapeutic strategies for treating various medical conditions. Additionally, understanding the structure and function of cnidarian venom components has inspired the design of novel bioactive molecules with potential applications in drug discovery, pest control, and other areas of biotechnology.

Apoptosis is a programmed and controlled cell death process that occurs in multicellular organisms. It is a natural process that helps maintain tissue homeostasis by eliminating damaged, infected, or unwanted cells. During apoptosis, the cell undergoes a series of morphological changes, including cell shrinkage, chromatin condensation, and fragmentation into membrane-bound vesicles called apoptotic bodies. These bodies are then recognized and engulfed by neighboring cells or phagocytic cells, preventing an inflammatory response. Apoptosis is regulated by a complex network of intracellular signaling pathways that involve proteins such as caspases, Bcl-2 family members, and inhibitors of apoptosis (IAPs).

C57BL/6 (C57 Black 6) is an inbred strain of laboratory mouse that is widely used in biomedical research. The term "inbred" refers to a strain of animals where matings have been carried out between siblings or other closely related individuals for many generations, resulting in a population that is highly homozygous at most genetic loci.

The C57BL/6 strain was established in 1920 by crossing a female mouse from the dilute brown (DBA) strain with a male mouse from the black strain. The resulting offspring were then interbred for many generations to create the inbred C57BL/6 strain.

C57BL/6 mice are known for their robust health, longevity, and ease of handling, making them a popular choice for researchers. They have been used in a wide range of biomedical research areas, including studies of cancer, immunology, neuroscience, cardiovascular disease, and metabolism.

One of the most notable features of the C57BL/6 strain is its sensitivity to certain genetic modifications, such as the introduction of mutations that lead to obesity or impaired glucose tolerance. This has made it a valuable tool for studying the genetic basis of complex diseases and traits.

Overall, the C57BL/6 inbred mouse strain is an important model organism in biomedical research, providing a valuable resource for understanding the genetic and molecular mechanisms underlying human health and disease.

Toxoids are inactivated bacterial toxins that have lost their toxicity but retain their antigenicity. They are often used in vaccines to stimulate an immune response and provide protection against certain diseases without causing the harmful effects associated with the active toxin. The process of converting a toxin into a toxoid is called detoxication, which is typically achieved through chemical or heat treatment.

One example of a toxoid-based vaccine is the diphtheria and tetanus toxoids (DT) or diphtheria, tetanus, and pertussis toxoids (DTaP or TdaP) vaccines. These vaccines contain inactivated forms of the diphtheria and tetanus toxins, as well as inactivated pertussis toxin in the case of DTaP or TdaP vaccines. By exposing the immune system to these toxoids, the body learns to recognize and mount a response against the actual toxins produced by the bacteria, thereby providing immunity and protection against the diseases they cause.

Biological models, also known as physiological models or organismal models, are simplified representations of biological systems, processes, or mechanisms that are used to understand and explain the underlying principles and relationships. These models can be theoretical (conceptual or mathematical) or physical (such as anatomical models, cell cultures, or animal models). They are widely used in biomedical research to study various phenomena, including disease pathophysiology, drug action, and therapeutic interventions.

Examples of biological models include:

1. Mathematical models: These use mathematical equations and formulas to describe complex biological systems or processes, such as population dynamics, metabolic pathways, or gene regulation networks. They can help predict the behavior of these systems under different conditions and test hypotheses about their underlying mechanisms.
2. Cell cultures: These are collections of cells grown in a controlled environment, typically in a laboratory dish or flask. They can be used to study cellular processes, such as signal transduction, gene expression, or metabolism, and to test the effects of drugs or other treatments on these processes.
3. Animal models: These are living organisms, usually vertebrates like mice, rats, or non-human primates, that are used to study various aspects of human biology and disease. They can provide valuable insights into the pathophysiology of diseases, the mechanisms of drug action, and the safety and efficacy of new therapies.
4. Anatomical models: These are physical representations of biological structures or systems, such as plastic models of organs or tissues, that can be used for educational purposes or to plan surgical procedures. They can also serve as a basis for developing more sophisticated models, such as computer simulations or 3D-printed replicas.

Overall, biological models play a crucial role in advancing our understanding of biology and medicine, helping to identify new targets for therapeutic intervention, develop novel drugs and treatments, and improve human health.

Macrophages are a type of white blood cell that are an essential part of the immune system. They are large, specialized cells that engulf and destroy foreign substances, such as bacteria, viruses, parasites, and fungi, as well as damaged or dead cells. Macrophages are found throughout the body, including in the bloodstream, lymph nodes, spleen, liver, lungs, and connective tissues. They play a critical role in inflammation, immune response, and tissue repair and remodeling.

Macrophages originate from monocytes, which are a type of white blood cell produced in the bone marrow. When monocytes enter the tissues, they differentiate into macrophages, which have a larger size and more specialized functions than monocytes. Macrophages can change their shape and move through tissues to reach sites of infection or injury. They also produce cytokines, chemokines, and other signaling molecules that help coordinate the immune response and recruit other immune cells to the site of infection or injury.

Macrophages have a variety of surface receptors that allow them to recognize and respond to different types of foreign substances and signals from other cells. They can engulf and digest foreign particles, bacteria, and viruses through a process called phagocytosis. Macrophages also play a role in presenting antigens to T cells, which are another type of immune cell that helps coordinate the immune response.

Overall, macrophages are crucial for maintaining tissue homeostasis, defending against infection, and promoting wound healing and tissue repair. Dysregulation of macrophage function has been implicated in a variety of diseases, including cancer, autoimmune disorders, and chronic inflammatory conditions.

"Vibrio cholerae" is a species of gram-negative, comma-shaped bacteria that is the causative agent of cholera, a diarrheal disease. It can be found in aquatic environments, such as estuaries and coastal waters, and can sometimes be present in raw or undercooked seafood. The bacterium produces a toxin called cholera toxin, which causes the profuse, watery diarrhea that is characteristic of cholera. In severe cases, cholera can lead to dehydration and electrolyte imbalances, which can be life-threatening if not promptly treated with oral rehydration therapy or intravenous fluids.

Protein biosynthesis is the process by which cells generate new proteins. It involves two major steps: transcription and translation. Transcription is the process of creating a complementary RNA copy of a sequence of DNA. This RNA copy, or messenger RNA (mRNA), carries the genetic information to the site of protein synthesis, the ribosome. During translation, the mRNA is read by transfer RNA (tRNA) molecules, which bring specific amino acids to the ribosome based on the sequence of nucleotides in the mRNA. The ribosome then links these amino acids together in the correct order to form a polypeptide chain, which may then fold into a functional protein. Protein biosynthesis is essential for the growth and maintenance of all living organisms.

I'm sorry for any confusion, but "Exfoliatins" is not a recognized medical term or a known medical condition. It seems like there might be a spelling mistake or a mix-up with the terminology. Exfoliation refers to the natural process of shedding dead skin cells from the surface of the skin. If you have any specific concerns about skin issues or other health problems, I would recommend consulting a healthcare professional for accurate information and advice tailored to your situation.

I cannot find a specific medical term called "killer factors" in the context of yeast. However, there is a phenomenon known as "killer yeasts," where certain strains of yeast produce proteins that can kill other strains of yeast. These proteins are referred to as "killer toxins."

Killer yeasts have been found in various species, including Saccharomyces cerevisiae and Saccharomyces bayanus. The killer toxin produced by these yeasts targets specific receptors on the cell membrane of sensitive yeast cells, leading to ion imbalance, disruption of cellular processes, and eventually cell death.

Therefore, "killer factors" in the context of yeast may refer to the genetic elements or proteins that enable certain strains of yeast to produce killer toxins and kill other sensitive yeast cells.

Endotoxins are toxic substances that are associated with the cell walls of certain types of bacteria. They are released when the bacterial cells die or divide, and can cause a variety of harmful effects in humans and animals. Endotoxins are made up of lipopolysaccharides (LPS), which are complex molecules consisting of a lipid and a polysaccharide component.

Endotoxins are particularly associated with gram-negative bacteria, which have a distinctive cell wall structure that includes an outer membrane containing LPS. These toxins can cause fever, inflammation, and other symptoms when they enter the bloodstream or other tissues of the body. They are also known to play a role in the development of sepsis, a potentially life-threatening condition characterized by a severe immune response to infection.

Endotoxins are resistant to heat, acid, and many disinfectants, making them difficult to eliminate from contaminated environments. They can also be found in a variety of settings, including hospitals, industrial facilities, and agricultural operations, where they can pose a risk to human health.

'Bordetella pertussis' is a gram-negative, coccobacillus bacterium that is the primary cause of whooping cough (pertussis) in humans. This highly infectious disease affects the respiratory system, resulting in severe coughing fits and other symptoms. The bacteria's ability to evade the immune system and attach to ciliated epithelial cells in the respiratory tract contributes to its pathogenicity.

The bacterium produces several virulence factors, including pertussis toxin, filamentous hemagglutinin, fimbriae, and tracheal cytotoxin, which contribute to the colonization and damage of respiratory tissues. The pertussis toxin, in particular, is responsible for many of the clinical manifestations of the disease, such as the characteristic whooping cough and inhibition of immune responses.

Prevention and control measures primarily rely on vaccination using acellular pertussis vaccines (aP) or whole-cell pertussis vaccines (wP), which are included in combination with other antigens in pediatric vaccines. Continuous efforts to improve vaccine efficacy, safety, and coverage are essential for controlling the global burden of whooping cough caused by Bordetella pertussis.

Sea Anemones are not considered a medical term, but they are rather marine biology organisms. They are a group of predatory sea animals belonging to the phylum Cnidaria, which also includes corals, jellyfish, and hydras. Sea anemones typically have a cylindrical or bell-shaped body crowned with tentacles that bear stinging cells used for capturing prey.

However, in a medical context, the term "anemone" is sometimes used to describe a type of skin lesion characterized by its resemblance to the sea anemone's shape and appearance. An anemone lesion is a rare cutaneous condition that presents as a solitary, red, or purple papule with multiple radiating fronds, often occurring on the face or neck. The lesions may be tender or pruritic (itchy) and can persist for several weeks to months.

It's important to note that sea anemones themselves do not have a direct medical relevance, but they can serve as a source of inspiration for medical terminology due to their unique morphological features.

Anthrax is a serious infectious disease caused by gram-positive, rod-shaped bacteria called Bacillus anthracis. This bacterium produces spores that can survive in the environment for many years. Anthrax can be found naturally in soil and commonly affects animals such as cattle, sheep, and goats. Humans can get infected with anthrax by handling contaminated animal products or by inhaling or coming into contact with contaminated soil, water, or vegetation.

There are three main forms of anthrax infection:

1. Cutaneous anthrax: This is the most common form and occurs when the spores enter the body through a cut or abrasion on the skin. It starts as a painless bump that eventually develops into a ulcer with a black center.
2. Inhalation anthrax (also known as wool-sorter's disease): This occurs when a person inhales anthrax spores, which can lead to severe respiratory symptoms and potentially fatal illness.
3. Gastrointestinal anthrax: This form is rare and results from consuming contaminated meat. It causes nausea, vomiting, abdominal pain, and diarrhea, which may be bloody.

Anthrax can be treated with antibiotics, but early diagnosis and treatment are crucial for a successful outcome. Preventive measures include vaccination and avoiding contact with infected animals or contaminated animal products. Anthrax is also considered a potential bioterrorism agent due to its ease of dissemination and high mortality rate if left untreated.

Shellfish poisoning refers to illnesses caused by the consumption of shellfish contaminated with harmful toxins produced by certain types of microscopic algae. These toxins can accumulate in various species of shellfish, including mussels, clams, oysters, and scallops, and can cause a range of symptoms depending on the specific type of toxin involved.

There are several types of shellfish poisoning, each caused by different groups of algal toxins:

1. Paralytic Shellfish Poisoning (PSP): Caused by saxitoxins produced by dinoflagellates such as Alexandrium spp., Gymnodinium catenatum, and Pyrodinium bahamense. Symptoms include tingling or numbness of the lips, tongue, and fingers, followed by weakness, difficulty swallowing, and potentially paralysis and respiratory failure in severe cases.
2. Amnesic Shellfish Poisoning (ASP): Caused by domoic acid produced by diatoms such as Pseudo-nitzschia spp. Symptoms include gastrointestinal distress, memory loss, disorientation, seizures, and in severe cases, coma or death.
3. Diarrheal Shellfish Poisoning (DSP): Caused by okadaic acid and its derivatives produced by dinoflagellates such as Dinophysis spp. and Prorocentrum spp. Symptoms include diarrhea, nausea, vomiting, abdominal cramps, and occasionally chills and fever.
4. Neurotoxic Shellfish Poisoning (NSP): Caused by brevetoxins produced by dinoflagellates such as Karenia brevis. Symptoms include reversible neurological symptoms like tingling or numbness of the lips, tongue, and fingers, as well as respiratory irritation, coughing, and chest tightness in severe cases.
5. Azaspiracid Shellfish Poisoning (AZP): Caused by azaspiracids produced by dinoflagellates such as Azadinium spp. Symptoms include gastrointestinal distress, nausea, vomiting, diarrhea, and abdominal pain.

It is essential to note that shellfish contaminated with these toxins may not show visible signs of spoilage or illness-causing bacteria; therefore, it is crucial to avoid consuming them during harmful algal blooms (HABs) or red tide events. Public health authorities often issue warnings and close shellfish beds when HABs are detected in the water. Always check local advisories before consuming shellfish, especially if you have harvested them yourself. Cooking does not destroy these toxins, so they remain harmful even after cooking.

Pseudomembranous enterocolitis is a medical condition characterized by inflammation of the inner lining of the small intestine (enteritis) and large intestine (colitis), resulting in the formation of pseudomembranes – raised, yellowish-white plaques composed of fibrin, mucus, and inflammatory cells. The condition is most commonly caused by a toxin produced by the bacterium Clostridioides difficile (C. difficile), which can overgrow in the gut following disruption of the normal gut microbiota, often after antibiotic use. Symptoms may include diarrhea, abdominal cramps, fever, nausea, and dehydration. Severe cases can lead to complications such as sepsis, toxic megacolon, or even death if left untreated. Treatment typically involves discontinuing the offending antibiotic, administering oral metronidazole or vancomycin to eliminate C. difficile, and managing symptoms with supportive care. In some cases, fecal microbiota transplantation (FMT) may be considered as a treatment option.

Clostridium infections are caused by bacteria of the genus Clostridium, which are gram-positive, rod-shaped, spore-forming, and often anaerobic organisms. These bacteria can be found in various environments, including soil, water, and the human gastrointestinal tract. Some Clostridium species can cause severe and potentially life-threatening infections in humans. Here are some of the most common Clostridium infections with their medical definitions:

1. Clostridioides difficile infection (CDI): An infection caused by the bacterium Clostridioides difficile, previously known as Clostridium difficile. It typically occurs after antibiotic use disrupts the normal gut microbiota, allowing C. difficile to overgrow and produce toxins that cause diarrhea, colitis, and other gastrointestinal symptoms. Severe cases can lead to sepsis, toxic megacolon, or even death.
2. Clostridium tetani infection: Also known as tetanus, this infection is caused by the bacterium Clostridium tetani. The spores of this bacterium are commonly found in soil and animal feces. They can enter the body through wounds, cuts, or punctures, germinate, and produce a potent exotoxin called tetanospasmin. This toxin causes muscle stiffness and spasms, particularly in the neck and jaw (lockjaw), which can lead to difficulty swallowing, breathing, and potentially fatal complications.
3. Clostridium botulinum infection: This infection is caused by the bacterium Clostridium botulinum and results in botulism, a rare but severe paralytic illness. The bacteria produce neurotoxins (botulinum toxins) that affect the nervous system, causing symptoms such as double vision, drooping eyelids, slurred speech, difficulty swallowing, dry mouth, and muscle weakness. In severe cases, botulism can lead to respiratory failure and death.
4. Gas gangrene (Clostridium perfringens infection): A rapidly progressing soft tissue infection caused by Clostridium perfringens or other clostridial species. The bacteria produce potent exotoxins that cause tissue destruction, gas production, and widespread necrosis. Gas gangrene is characterized by severe pain, swelling, discoloration, and a foul-smelling discharge. If left untreated, it can lead to sepsis, multi-organ failure, and death.
5. Clostridioides difficile infection (C. difficile infection): Although not caused by a typical clostridial species, C. difficile is a gram-positive, spore-forming bacterium that can cause severe diarrhea and colitis, particularly in hospitalized patients or those who have recently taken antibiotics. The bacteria produce toxins A and B, which damage the intestinal lining and contribute to inflammation and diarrhea. C. difficile infection can range from mild to life-threatening, with complications such as sepsis, toxic megacolon, and bowel perforation.

Medical Definition:

Lethal Dose 50 (LD50) is a standard measurement in toxicology that refers to the estimated amount or dose of a substance, which if ingested, injected, inhaled, or absorbed through the skin by either human or animal, would cause death in 50% of the test population. It is expressed as the mass of a substance per unit of body weight (mg/kg, μg/kg, etc.). LD50 values are often used to compare the toxicity of different substances and help determine safe dosage levels.

Trihexosylceramides are a type of glycosphingolipids, which are complex lipids found in animal tissues. They consist of a ceramide molecule (a sphingosine and fatty acid) with three hexose sugars attached to it in a specific sequence, typically glucose-galactose-galactose.

Trihexosylceramides are further classified into two types based on the type of ceramide they contain: lactosylceramide (Gal-Glc-Cer) and isoglobotrihexosylceramide (GalNAcβ1-4Galβ1-4Glc-Cer).

These lipids are important components of the cell membrane and play a role in various biological processes, including cell recognition, signal transduction, and cell adhesion. Abnormal accumulation of trihexosylceramides has been implicated in certain diseases, such as Gaucher disease and Tay-Sachs disease, which are caused by deficiencies in enzymes involved in their breakdown.

Biological pest control, also known as biocontrol, is a method of managing or eliminating pests such as insects, mites, weeds, and plant diseases using natural enemies or other organisms. These biological control agents include predators, parasites, pathogens, and competitors that regulate pest populations and reduce the need for chemical pesticides. Biological pest control is a key component of integrated pest management (IPM) programs and has minimal impact on the environment compared to traditional pest control methods.

'Corynebacterium diphtheriae' is a gram-positive, rod-shaped, aerobic bacteria that can cause the disease diphtheria. It is commonly found in the upper respiratory tract and skin of humans and can be transmitted through respiratory droplets or direct contact with contaminated objects. The bacterium produces a potent exotoxin that can cause severe inflammation and formation of a pseudomembrane in the throat, leading to difficulty breathing and swallowing. In severe cases, the toxin can spread to other organs, causing serious complications such as myocarditis (inflammation of the heart muscle) and peripheral neuropathy (damage to nerves outside the brain and spinal cord). The disease is preventable through vaccination with the diphtheria toxoid-containing vaccine.

"Shigella dysenteriae" is a specific species of bacteria that can cause severe forms of dysentery, a type of diarrheal disease. The infection caused by this bacterium is known as shigellosis. Shigella dysenteriae is highly infectious and can be transmitted through direct contact with an infected person or through contaminated food or water.

The bacteria produce toxins that can cause inflammation and damage to the lining of the intestine, leading to symptoms such as diarrhea (often containing blood and mucus), abdominal cramps, fever, and tenesmus (the urgent need to have a bowel movement). In severe cases, shigellosis can lead to complications such as dehydration, seizures, and hemolytic-uremic syndrome (HUS), a serious condition that can cause kidney failure.

Shigella dysenteriae is a public health concern, particularly in areas with poor sanitation and hygiene practices. Prevention measures include good hand hygiene, safe food handling practices, and access to clean water. Treatment typically involves antibiotics, fluids, and electrolyte replacement to manage symptoms and prevent complications.

Trichothecenes are a group of chemically related toxic compounds called sesquiterpenoids produced by various species of fungi, particularly those in the genera Fusarium, Myrothecium, Trichoderma, Trichothecium, and Stachybotrys. These toxins can contaminate crops and cause a variety of adverse health effects in humans and animals that consume or come into contact with the contaminated material.

Trichothecenes can be classified into four types (A, B, C, and D) based on their chemical structure. Type A trichothecenes include T-2 toxin and diacetoxyscirpenol, while type B trichothecenes include deoxynivalenol (DON), nivalenol, and 3-acetyldeoxynivalenol.

Exposure to trichothecenes can cause a range of symptoms, including skin irritation, nausea, vomiting, diarrhea, abdominal pain, and immune system suppression. In severe cases, exposure to high levels of these toxins can lead to neurological problems, hemorrhage, and even death.

It is important to note that trichothecenes are not typically considered infectious agents, but rather toxin-producing molds that can contaminate food and other materials. Proper handling, storage, and preparation of food can help reduce the risk of exposure to these toxins.

'Clostridium' is a genus of gram-positive, rod-shaped bacteria that are widely distributed in nature, including in soil, water, and the gastrointestinal tracts of animals and humans. Many species of Clostridium are anaerobic, meaning they can grow and reproduce in environments with little or no oxygen. Some species of Clostridium are capable of producing toxins that can cause serious and sometimes life-threatening illnesses in humans and animals.

Some notable species of Clostridium include:

* Clostridium tetani, which causes tetanus (also known as lockjaw)
* Clostridium botulinum, which produces botulinum toxin, the most potent neurotoxin known and the cause of botulism
* Clostridium difficile, which can cause severe diarrhea and colitis, particularly in people who have recently taken antibiotics
* Clostridium perfringens, which can cause food poisoning and gas gangrene.

It is important to note that not all species of Clostridium are harmful, and some are even beneficial, such as those used in the production of certain fermented foods like sauerkraut and natto. However, due to their ability to produce toxins and cause illness, it is important to handle and dispose of materials contaminated with Clostridium species carefully, especially in healthcare settings.

Elapid venoms are the toxic secretions produced by elapid snakes, a family of venomous snakes that includes cobras, mambas, kraits, and coral snakes. These venoms are primarily composed of neurotoxins, which can cause paralysis and respiratory failure in prey or predators.

Elapid venoms work by targeting the nervous system, disrupting communication between the brain and muscles. This results in muscle weakness, paralysis, and eventually respiratory failure if left untreated. Some elapid venoms also contain hemotoxins, which can cause tissue damage, bleeding, and other systemic effects.

The severity of envenomation by an elapid snake depends on several factors, including the species of snake, the amount of venom injected, the location of the bite, and the size and health of the victim. Prompt medical treatment is essential in cases of elapid envenomation, as the effects of the venom can progress rapidly and lead to serious complications or death if left untreated.

Elapidae is a family of venomous snakes, also known as elapids. This family includes many well-known species such as cobras, mambas, death adders, and sea snakes. Elapids are characterized by their fixed fangs, which are located at the front of the upper jaw and deliver venom through a hollow canal. The venom of these snakes is typically neurotoxic, causing paralysis and respiratory failure in prey or attackers.

Elapids are found throughout the world, with the greatest diversity occurring in tropical regions. They vary widely in size, from small species like the death adders that measure only a few inches long, to large species like the king cobra, which can reach lengths of up to 18 feet (5.5 meters).

Elapids are generally shy and avoid confrontations with humans whenever possible. However, they will defend themselves aggressively if threatened or cornered. Bites from elapid snakes can be medically significant and may require antivenom treatment.

A biological assay is a method used in biology and biochemistry to measure the concentration or potency of a substance (like a drug, hormone, or enzyme) by observing its effect on living cells or tissues. This type of assay can be performed using various techniques such as:

1. Cell-based assays: These involve measuring changes in cell behavior, growth, or viability after exposure to the substance being tested. Examples include proliferation assays, apoptosis assays, and cytotoxicity assays.
2. Protein-based assays: These focus on measuring the interaction between the substance and specific proteins, such as enzymes or receptors. Examples include enzyme-linked immunosorbent assays (ELISAs), radioimmunoassays (RIAs), and pull-down assays.
3. Genetic-based assays: These involve analyzing the effects of the substance on gene expression, DNA structure, or protein synthesis. Examples include quantitative polymerase chain reaction (qPCR) assays, reporter gene assays, and northern blotting.

Biological assays are essential tools in research, drug development, and diagnostic applications to understand biological processes and evaluate the potential therapeutic efficacy or toxicity of various substances.

Saxitoxin (STX) is a potent neurotoxin that inhibits the sodium channels in nerve cells, leading to paralysis and potentially death. It is produced by certain species of marine dinoflagellates and cyanobacteria, and can accumulate in shellfish that feed on these organisms. Saxitoxin poisoning, also known as paralytic shellfish poisoning (PSP), is a serious medical condition that can cause symptoms such as numbness, tingling, and paralysis of the mouth and extremities, as well as respiratory failure and death in severe cases. It is important to note that saxitoxin is not used as a therapeutic agent in medicine and is considered a harmful substance.

Bacterial antibodies are a type of antibodies produced by the immune system in response to an infection caused by bacteria. These antibodies are proteins that recognize and bind to specific antigens on the surface of the bacterial cells, marking them for destruction by other immune cells. Bacterial antibodies can be classified into several types based on their structure and function, including IgG, IgM, IgA, and IgE. They play a crucial role in the body's defense against bacterial infections and provide immunity to future infections with the same bacteria.

Bacterial toxins). ... Alpha-toxin has been shown to play a role in pathogenesis of ... Alpha-toxin is also one of the key virulence factors in S. aureus pneumonia. The level of alpha-toxin expressed by a particular ... The dosage of toxin can result in two different modes of activity. Low concentrations of toxin bind to specific, but ... This activity was inhibited when two different anti-alpha-toxin antibodies were introduced. In the same study, alpha toxin was ...
Many bacterial toxins nucleotide-binding modify by ADP-ribosylation proteins involved in essential cell functions, leading to ... cholera-like toxins, binary toxins and C3-like exoenzymes. C3-like exoenzymes unlike other ADP-ribosyltransferase toxins do not ... All the toxins of this family share a highly conserved glutamate, which is the catalytic residue critical for the NAD- ... Clostridium botulinum C3 exoenzyme is a toxin that causes the addition of one or more ADP-ribose moieties to Rho-like proteins ...
ISBN 978-0-323-05470-6. (Bacterial toxins). ... Staphylococcus aureus beta toxin is a toxin produced by ... The beta toxin exhibits maximum activity at 10 °C, at 37 °C (normal body temperature) seems to be inactive. Cifrian E, Guidry ... Gaskin DK, Bohach GA, Schlievert PM, Hovde CJ (February 1997). "Purification of Staphylococcus aureus beta-toxin: comparison of ... AJ, Bramley AJ, Norcross NL, Bastida-Corcuera FD, Marquardt WW (February 1996). "Effect of staphylococcal beta toxin on the ...
Todar K (2012). "Bacterial Protein Toxins". Todar's Online Textbook of Bacteriology. Madison, Wisconsin. Edwin C, Parsonnet J, ... In general, the toxin is not produced by bacteria growing in the blood; rather, it is produced at the local site of an ... Toxic shock syndrome toxin-1 (TSST-1) is a superantigen with a size of 22 kDa produced by 5 to 25% of Staphylococcus aureus ... These studies containing TSST-1 indicate that the TCR binding domain lies at the top of the back side of this toxin, though the ...
The most prominent natural toxin groups that exist in aquatic environments are mycotoxins, algal toxins, bacterial toxins, and ... Alpha toxin Anthrax toxin Dinotoxin Cyanotoxin Diphtheria toxin Exotoxin Pertussis toxin Shiga toxin Shiga-like toxin K R ... Toxin A and toxin B are two toxins produced by Clostridium difficile. Toxin A and toxin B are glycosyltransferases that cause ... Although these are not viral toxins, researchers remain extremely interested in the role phages play bacterial toxins due to ...
... is structurally related to a large family of bacterial toxins - RTX toxins. Differences between the toxins of different ... but these toxin molecules are not active. Besides attachment to bacterial proteins, aggregation also inactivates the toxin. ... The toxin is secreted by the Type I secretion system, which spans both membranes and periplasm space, allowing the toxin to be ... It is a toxin secreted by the bacteria to influence the host immune system. Adenylate cyclase toxin from Bordetella pertussis ...
Bacterial toxins). ... is a member of the RTX-toxin superfamily. The Harpin-PSS (HrpZ ... It has been hypothesized that such channels could allow nutrient release and/or delivery of virulence factors during bacterial ...
Bacterial toxins). ... This protein is a member of the alpha pore forming toxins ... The protein has structural similarities to other toxins, including haemolysin E and B. cereus toxins HlbB and NheA. No other ... "The pesticidal Cry6Aa toxin from Bacillus thuringiensis is structurally similar to HlyE-family alpha pore-forming toxins". BMC ... "The pesticidal Cry6Aa toxin from Bacillus thuringiensis is structurally similar to HlyE-family alpha pore-forming toxins". BMC ...
... can be activated by components of the immune system, such as the complement system; bacterial toxins; activated ... Toxins and pathogens may cause necrosis; toxins such as snake venoms may inhibit enzymes and cause cell death. Necrotic wounds ... In the example of a snake bite, the use of anti-venom halts the spread of toxins whilst receiving antibiotics to impede ... This is typical of bacterial, or sometimes fungal, infections because of their ability to stimulate an inflammatory response. ...
In addition to some of these AB5 toxins being used to create vaccines to prevent bacterial infection, they are also being ... AB5 Toxins Biochemistry Cholera toxin Pertussis toxin Shiga toxin Subtilase Le Nours, J.; Paton, A. W.; Byres, E.; Troy, S.; ... Cholera toxin, pertussis toxin, and shiga toxin all have their targets in the cytosol of the cell. After their B subunit binds ... Under the categorize-by-A rule, it is a Ptx-family toxin. Shiga toxin, also known as Stx, is a toxin that is produced by the ...
... (also called Coley's toxin, Coley's vaccine, Coley vaccine, Coley's fluid or mixed bacterial vaccine) is a ... The FDA-approved BCG for non-muscle invasive bladder cancer is a highly related strategy of Coley's Toxin. Bacterial ... Thus, fever is seen as a precondition for a therapy using Coley's Toxins to succeed. One of the agents in Coley's Toxin that is ... "Coley's Toxins Cancer Treatment". Retrieved 2023-04-11. "Coley's Toxins - The First Century Townsend Letter for Doctors and ...
TcdA is one of the largest bacterial toxins known. With a molecular mass of 308 kDa, it is usually described as a potent ... Kuehne SA, Cartman ST, Heap JT, Kelly ML, Cockayne A, Minton NP (October 2010). "The role of toxin A and toxin B in Clostridium ... Clostridium difficile toxin A (TcdA) is a toxin generated by Clostridioides difficile, formerly known as Clostridium difficile ... It is similar to Clostridium difficile Toxin B. The toxins are the main virulence factors produced by the gram positive, ...
"Bacterial Pathogenesis: Bacterial Factors that Damage the Host - Producing Exotoxins - A-B Toxins". Archived from the original ... Zahaf N, Schmidt G (2017-07-18). "Bacterial Toxins for Cancer Therapy". Toxins (Basel). 9 (8): 236. doi:10.3390/toxins9080236. ... Examples of the "A" component of an AB toxin include C. perfringens iota toxin Ia, C. botulinum C2 toxin CI, and Clostridium ... The AB5 toxins are usually considered a type of AB toxin, characterized by B pentamers. Less commonly, the term "AB toxin" is ...
Some bacteria produce toxins, which cause diseases. These are endotoxins, which come from broken bacterial cells, and exotoxins ... Chattopadhyay A, Bhatnagar NB, Bhatnagar R (2004). "Bacterial insecticidal toxins". Critical Reviews in Microbiology. 30 (1): ... The most common fatal bacterial diseases are respiratory infections. Antibiotics are used to treat bacterial infections and are ... Luong P, Dube DH (July 2021). "Dismantling the bacterial glycocalyx: Chemical tools to probe, perturb, and image bacterial ...
Bacteriocins, Peptides, Bacterial toxins). ... They are also used to repress unwanted bacterial growth that ...
Dreyfus, Lawrence A. (2003), "Cyotlethal Distending Toxin", in D. Burns; et al. (eds.), Bacterial Protein Toxins, Washington, ... Individual cytolethal distending toxins are named for the bacterial species that they are isolated from. As of 2011, most ... Jinadasa RN, Bloom SE, Weiss RS, Duhamel GE (July 2011). "Cytolethal distending toxin: a conserved bacterial genotoxin that ... Cytolethal distending toxins are classified as AB toxins, with an active ("A") subunit that directly damages DNA and a binding ...
... which are toxins "within" the bacterial cell and released only after destruction of the bacterial outer membrane. Subsequent ... Lipopolysaccharides (LPS) are large molecules consisting of a lipid and a polysaccharide that are bacterial toxins. They are ... in the original sense of toxins that are inside the bacterial cell that are released when the cell disintegrates) that are not ... "TRP Channels as Sensors of Bacterial Endotoxins". Toxins. 10 (8): 326. doi:10.3390/toxins10080326. PMC 6115757. PMID 30103489. ...
Protein pages needing a picture, Bacterial toxins). ... Beta toxin is the principal disease causing toxin in C. ... C. perfringens beta toxin shows 28% homology with S. aureus alpha toxin and similar homology to S. aureus gamma-toxin and ... Because C. perfringens beta toxin shares homology with S. aureus pore-forming alpha toxin, it was hypothesized that beta toxin ... "Molecular genetic analysis of beta-toxin of Clostridium perfringens reveals sequence homology with alpha-toxin, gamma-toxin, ...
1949). "Formation of a Bacterial Toxin (Streptolysin S) by Resting Cells". Journal of Experimental Medicine. 90 (5): 373-392. ... Schwartz, Lois L. (1964). "Lysosomal Disruption by Bacterial Toxins". Journal of Bacteriology. 87 (5): 1100-1104. doi:10.1128/ ... 1974). "Interactions between membranes and cytolytic bacterial toxins". Biochimica et Biophysica Acta (BBA) - Reviews on ... 1988). "[30] Assay of hemolytic toxins". Microbial Toxins: Tools in Enzymology. Methods in Enzymology. Vol. 165. pp. 213-217. ...
Millar I, Gray D, Kay H (1998). "Bacterial toxins found in foods". In Watson DH (ed.). Natural Toxicants in Food. CRC Press. pp ... The Hbl and Nhe toxins are pore-forming toxins closely related to ClyA of E. coli. The proteins exhibit a conformation known as ... Emetic toxin can withstand 121 °C (250 °F) for 90 minutes. As a result of the emetic type's association with rice, it is ... This suggests that the agent also functions as a toxin against the GW-01 strain. This is significant as it shows that in the ...
Pizza, Mariagrazia; Fontana, Maria Rita; Scarlato, Vincenzo; Rappuoli, Rino (1996). "Genetic Detoxification of Bacterial Toxins ... She worked as Senior Scientific Director for Bacterial Vaccines at GSK plc. She was involved with the development of the first ...
Pizza, Mariagrazia; Fontana, Maria Rita; Scarlato, Vincenzo; Rappuoli, Rino (1996). "Genetic Detoxification of Bacterial Toxins ... a non-toxic mutant of diphtheria toxin: Use as a conjugation protein in vaccines and other potential clinical applications". ... conjugate vaccine against meningococcal-C disease and the first recombinant bacterial vaccine against pertussis. Currently,[ ... an acellular pertussis vaccine containing a genetically detoxified pertussis toxin; the first conjugate vaccines against ...
World Pneumonia Day (Bacterial toxins). ... It is a pore-forming toxin of 53 kDa composed of 471 amino ...
Buts L, Lah J, Dao-Thi MH, Wyns L, Loris R (December 2005). "Toxin-antitoxin modules as bacterial metabolic stress managers". ... Brielle R, Pinel-Marie ML, Felden B (April 2016). "Linking bacterial type I toxins with their actions" (PDF). Current Opinion ... The SymE-SymR toxin-antitoxin system consists of a small symbiotic endonuclease toxin, SymE, and a non-coding RNA symbiotic RNA ... In contrast to other common toxin-antitoxin systems, the SymR antitoxin is more stable than the SymE toxin. Following DNA ...
... or the release of soluble toxins (including colicins) in the environment. Polymorphic toxins are bacterial exotoxins which ... CdiA toxins Rhs toxins "Extended" VgrG toxins "Extended" Hcp toxins MafB toxins Hayes, C. S; Koskiniemi, S; Ruhe, Z. C; Poole, ... Zhang, Dapeng; Iyer, Lakshminarayan M; Aravind, L (2011). "A novel immunity system for bacterial nucleic acid degrading toxins ... The immunity protein is present in the cytoplasm to protect the toxin producing-cell both from auto-intoxication and from toxin ...
When a polymorphic toxin with anti-bacterial activity is produced by a bacterial strain, this strain is protected by a specific ... Rhs toxins belong to the polymorphic toxin category of bacterial exotoxins. Rhs proteins are widespread and can be produced by ... These toxins encompass Rhs toxins of insect pathogens with an activity against insects. This group also include Rhs toxins with ... Jamet A, Nassif X (May 2015). "New players in the toxin field: polymorphic toxin systems in bacteria". mBio. 6 (3): e00285-15. ...
Van Melderen L, Saavedra De Bast M (March 2009). "Bacterial toxin-antitoxin systems: more than selfish entities?". PLOS Genet. ... a 35 amino acid peptide toxin (ldrD) and a 60 nucleotide RNA antitoxin. The 374nt toxin mRNA has a half-life of around 30 ... RdlD RNA (regulator detected in LDR-D) is a family of small non-coding RNAs which repress the protein LdrD in a type I toxin- ... Toxin-antitoxin system Hok/sok system RatA Kawano M, Oshima T, Kasai H, Mori H (July 2002). "Molecular characterization of long ...
158-. ISBN 978-0-306-44077-9. Hardegree, M. Carolyn; Tu, Anthony T. (5 August 1988). Handbook of Natural Toxins: Bacterial ... "Cholera Toxins: Immunogenicity of the Rabbit Ileal Loop Toxin and Related Antigens" (PDF). American Society for Microbiology. ... Dutta N. K., Panse N. V., Kulkarni D. R. (1959). "Role of cholera a toxin in experimental cholera". J. Bacteriol. 78 (4): 594-5 ... Dutta was associated with the World Health Organization, serving as a member of their Experts' Panel in Bacterial Diseases and ...
ADP-ribosylation is a common enzymatic method used by different bacterial toxins from various species. Toxins such as C. ... Binary toxins, such as anthrax lethal and edema toxins (Main article: Anthrax toxin), C. perfringens iota toxin and C. ... Insecticidal toxins in the Toxin-10 family show an overall similarity to the aerolysin and Etx/Mtx2 toxin structures but differ ... With the exception of Cry36 and Cry78, the Toxin_10 toxins appear to act as two-part, binary toxins. The partner proteins in ...
Protein pages needing a picture, Bacterial toxins). ... The E. coli toxin B protein (TC# 1.C.57.2.1) and the Chlamydial ... The distantly related ToxA toxin of Pasteurella multocida (TC# 1.C.57.3.1) is 1285 aas while the E. coli Cnf1 and 2 toxins(TC#s ... difficile Toxin B and C as well as Clostridium sordellii lethal toxin (TcsL). Low pH presumably induces conformational/ ... Clostridium difficile toxin B Clostridium difficile colitis Clostridium difficile (bacteria) RTX toxin Transporter ...
Pneumolysin is a 53 kDa bacterial protein toxin that inserts into eukaryotic membranes where it self-associates to form pores ... The development of experimental and computational tools for studying protein interactions: Applied to the bacterial toxin ... This process involves the initial interaction between toxin and membrane, followed by interaction between toxin monomers. ... Applied to the bacterial toxin pneumolysin. PhD thesis, University of Glasgow. ...
Activation of the unfolded protein response is required for defenses against bacterial pore-forming toxin in vivo. PLoS Pathog ... Activation of the unfolded protein response is required for defenses against bacterial pore-forming toxin in vivo. ... Activation of the unfolded protein response is required for defenses against bacterial pore-forming toxin in vivo. ...
Bacterial Strains. For this study, we used STEC strains from the culture collections at the Istituto Superiore di Sanità and ... Yang X, Bai X, Zhang J, Sun H, Fu S, Fan R, et al. Escherichia coli strains producing a novel Shiga toxin 2 subtype circulate ... Ingelbeen B, Bruyand M, Mariani-Kurkjian P, Le Hello S, Danis K, Sommen C, et al. Emerging Shiga-toxin-producing Escherichia ... OBrien AD, Tesh VL, Donohue-Rolfe A, Jackson MP, Olsnes S, Sandvig K, et al. Shiga toxin: biochemistry, genetics, mode of ...
1999). Bacterial toxins: friends or foes?. 5(2). Schmitt, C. K. and Meysick, K. C. and OBrien, A. D. "Bacterial toxins: ... Animals Bacterial Toxins Bacterial Vaccines Botulinum Toxins Cytotoxins Enterotoxins Escherichia Coli Proteins Humans ... We highlight seven bacterial toxins produced by well-established or newly emergent pathogenic microbes. These toxins, which ... Title : Bacterial toxins: friends or foes? Personal Author(s) : Schmitt, C. K.;Meysick, K. C.;OBrien, A. D.; Published Date : ...
Bacterial toxins). ... Alpha-toxin has been shown to play a role in pathogenesis of ... Alpha-toxin is also one of the key virulence factors in S. aureus pneumonia. The level of alpha-toxin expressed by a particular ... The dosage of toxin can result in two different modes of activity. Low concentrations of toxin bind to specific, but ... This activity was inhibited when two different anti-alpha-toxin antibodies were introduced. In the same study, alpha toxin was ...
Discussion on: An Overview of Bacterial Superantigen Toxins, CD28, and Drug Development Media Promotion ...
Bacterial isolates from four HUS cases reported in Arizona (1), Massachusetts (1), Michigan (1) and Wisconsin (1), and two ... Outbreak of Shiga toxin-producing E. coli O104 (STEC O104:H4) Infections Associated with Travel to Germany (FINAL UPDATE). ... One is its ability to stick to cells in the intestine and another is its ability to make Shiga toxin. These factors are already ... CDC is monitoring a large outbreak of Shiga toxin-producing Escherichia coli O104:H4 (STEC O104:H4) infections ongoing in ...
Biological weapons include any organism or toxin found in nature that can be used to incapacitate, kill, or otherwise impede an ... The anthrax toxins, like many bacterial and plant toxins, possess the following two components: a cell-binding B-domain and an ... Botulinum toxins are the most lethal toxins known and depending on the subtype, are 10,000-100,000 times more toxic than ... Anthrax and botulinum toxin initially were investigated for use as weapons, and sufficient quantities of botulinum toxin and ...
Toxins, an international, peer-reviewed Open Access journal. ... "Bacterial Toxins" MDPI is pleased to announce the appointment ... clear Back to TopTop ... of Jay W. Fox as the Editor-in-Chief of Toxins, and Michel R. Popoff as the Section Editor-in-Chief for "Bacterial Toxins". The ... Michel R. Popoff is Head of the Anaerobic Bacteria and Toxins Unit and the Director of the National Reference Center for ... -- A new tool for tracking algal toxins is under development at UC Santa Cruz. ... Deadly bacteria show thirst for human blood: Research outlines the phenomenon of bacterial vampirism. 4 hours ago ... Scientists develop new technology for tracking algal toxins. Sachets containing resin beads that absorb algal toxins are used ... "We know where the otters live and where they eat, but we have no idea where the toxins are coming from," Kudela said. "The idea ...
Microbial toxins and eukaryotic cell toxicity from indoor building materials heavily colonized by fungi and bacteria were ... This toxicity was not explainable by the amount of bacterial endotoxin, beta-D-glucan, or satratoxin present in the same ... Bacteria, molds, and toxins in water-damaged building materials Appl Environ Microbiol. 1997 Feb;63(2):387-93. doi: 10.1128/aem ... Microbial toxins and eukaryotic cell toxicity from indoor building materials heavily colonized by fungi and bacteria were ...
Nutri-Vet Anti-Diarrhea Liquid for Cats works against bacterial toxins and contains pectin, which provides a protective coating ... 6. Nutri-Vet Anti-Diarrhea Liquid For Cats , 4oz , Bacterial Toxin Detoxifier & Stomach Soother.. ... Nutri-Vet Anti-Diarrhea Liquid for Cats , 4oz , Bacterial Toxin Detoxifier & Stomach Soother. ... Nutri-Vet Anti-Diarrhea Liquid for Cats , 4oz , Bacterial Toxin Detoxifier & Stomach Soother. ...
Bacterial toxins in musculoskeletal infections.. Saeed, Kordo; Sendi, Parham; Arnold, William V; Bauer, Thomas W; Coraça-Huber ... Bacterial toxins are foundational to pathogenesis in MSKI, but poorly understood by the community of providers that care for ... further research to identify the roles of bacterial toxins in MSKIs, (ii) establish the understanding of the importance of ... The group concluded that further research is needed to maximize our understanding of the effect of toxins on MSKIs, including ( ...
Bacterial infections. * Toxins or poisoning. * Cancers or tumors. * Injuries. * A metabolic disorder ... Whether the infection is viral or bacterial, the body fights it by raising the cats internal body temperature by activating ...
Toxins of Gram-negative bacteria. Developing effective veterinary vaccines against bacterial pathogens. Investigating novel ... Antimicrobial resistance of bacterial Biofilms in collaboration with the Royal Childrens Hospital and Griffith University ... Epidemiology and virulence of Campylobacter concisus as an emerging bacterial pathogen. In collaboration with The Royal ... Application of molecular biology techniques for Pathogen detection, bacterial pathogenesis and vaccine development ...
The resulting active toxin would then target essential cellular processes and inhibit bacterial growth. Although interplay ... The resulting active toxin would then target essential cellular processes and inhibit bacterial growth. Although interplay ... It has been proposed that toxin activation or expression of the TA operon could rely on the degradation of generally less ... It has been proposed that toxin activation or expression of the TA operon could rely the degradation of generally less stable ...
Inactive toxin appeared to bind to the liposome but not to cause membrane alteration; subsequent activation of pneumolysin in ... We propose that the changes in membrane structure on toxin attack which we have observed are related to the mechanism by which ... The overall trend was a thinning of the liposome surface on toxin attack, which was countered by the formation of localized ... Two important aspects of the pore-forming activity of pneumolysin are therefore the effect of the toxin on bilayer membrane ...
a bacterial infection. *liver injury caused by a toxin (poison). *liver damage caused by interruption of the organs normal ... and helps clear toxins from the body. ...
NIOSH-Author; Organic-dusts; Airborne-dusts; Molds; Toxins; Plant-dusts; Plant-substances; Agriculture; Bacterial-dusts; ... The authors conclude that Gram negative bacterial endotoxins occur in silage and its related airborne dust. They are found in ... Airborne dusts generated during removal of the cap of moldy silage from silos were analyzed for Gram negative bacterial ...
Absorbs and helps remove bacterial toxins from the intestinal tract. Coats and soothes gastrointestinal membranes and helps ... Kaolin absorbs and helps remove bacterial toxins. *Helps prevent dehydration. *Comes in a palatable oral suspension ... Kaolin slows down the passage of feces while eliminating toxins. Helps prevent dehydration. Kolin Pectin comes in a palatable ...
So this would just be a normal bacterial cell, it is not going to be a serum resistant bacterial cell. And so without this ... And so notice that the regulatory protein is a protein on the surface of specifically serum resistant bacterial cells. And so ... All of these survival mechanisms are unique to serum resistant bacterial pathogens except which of the following? ... regulatory protein, C three B is able to bind to the bacterial cell surface and then it will associate with other complement ...
Another type of toxin food poisoning is from rice dishes. A common one is fried rice. The bacterial causes of food poisoning ... Causes. It is caused by toxins from germs growing in foods left out too long. High-risk for Staph toxins are moist food dishes ... Fever is uncommon in cases of toxin-induced food poisoning.. *What to expect. Symptoms from toxins usually begin within 1 to 12 ... If this happens, the bacteria can release toxin. The toxin affects the muscles and cause weakness. ...
Common fold of diphtheria toxin/transcription factors/cytochrome f ... b.2.3: Bacterial adhesins [49401] (7 families) *. b.2.5: p53-like transcription factors [49417] (8 families) ... Timeline for Fold b.2: Common fold of diphtheria toxin/transcription factors/cytochrome f: *Fold b.2: Common fold of diphtheria ... b.2.1: Diphtheria toxin, C-terminal domain [49380] (2 families) automatically mapped to Pfam PF01324. ...
It may be related to an autoimmune disorder, infection, or exposure to toxins. The type of uveitis that causes the worst red ... Corneal ulcers: Sores on the cornea most often caused by a serious bacterial or viral infection. ...
Categories: Bacterial Toxins Image Types: Photo, Illustrations, Video, Color, Black&White, PublicDomain, CopyrightRestricted ...
E. coli, mycobacteria and other bacterial pathogens, Isospora, Macrorhabdus, Chlamydophila, polyomavirus, circovirus and toxins ... Inhalant Toxins. Canaries and finches are particularly susceptible to inhalant toxins because they exchange more air per gram ... Bacterial Diseases. The general principles for diagnosing, treating and controlling bacterial disease in Passeriformes are ... Differential diagnoses include toxins (organophosphates, dimetridazole), trauma, atoxoplasma and bacterial meningoencephalitis ...
We are studying the structures of bacterial toxins that form ion channels and catalyze macromolecule transport across membranes ...
By contrast, extensive bacteremia, when it is associated with the release of bacterial toxins into the circulation (septicemia ... with preventive antibiotic therapy being given to forestall extensive bacterial invasion of the bloodstream. Despite such ... or for those with debilitating medical conditions that increase susceptibility to bacterial invasion. ...
02042 Bacterial toxins. 02022 Two-component system. 02035 Bacterial motility proteins. 04812 Cytoskeleton proteins. 04147 ...
Gram stain including bacterial morphology; direct bacterial antigen detection; *bacterial toxin detection; ... could be misconstrued included urine colony count and a PCR assay reporting bacterial vaginitis from yeast infections. Instead ...
  • Shiga toxin-producing Escherichia coli (STEC) O80:H2 has emerged in Europe as a cause of hemolytic uremic syndrome associated with bacteremia. (
  • Shiga toxin-producing Escherichia coli (STEC) is a group of enteric pathogens that cause foodborne disease ranging from uncomplicated diarrhea to hemorrhagic colitis (HC) or hemolytic uremic syndrome (HUS) ( 1 ). (
  • CDC is monitoring a large outbreak of Shiga toxin-producing Escherichia coli O104:H4 (STEC O104:H4) infections ongoing in Germany. (
  • Shiga toxin-producing Escherichia coli (STEC) can cause diarrhea, bloody diarrhea (hemorrhagic colitis), and hemolytic uremic syndrome (HUS) in persons of any age. (
  • STEC strains produce Shiga toxins (Stx), a family composed of 2 main types of cytotoxins: Stx1 and Stx2 ( 2 ). (
  • As of July 5, 2011, case counts confirmed by Germany's Robert Koch Institute include 852 patients with hemolytic uremic syndrome (HUS)-a type of kidney failure that is associated with Shiga toxin-producing E. coli, or STEC, infections-and 32 HUS-associated deaths. (
  • CDC has alerted state health departments of the ongoing outbreak and requested information about any persons with either HUS or Shiga toxin-positive diarrheal illness, with illness onset during or after travel to Germany and since April 1, 2011. (
  • All STEC produce Shiga toxin . (
  • All STEC produce one or more of two similar toxins, Shiga toxin 1 and Shiga toxin 2. (
  • The toxins are named for Dr. Shiga, who first described the bacterial origin of dysentery caused by a rare type of Shigella ( Shigella dysenteriae type 1) that produces Shiga toxin 1. (
  • Activation of the unfolded protein response is required for defenses against bacterial pore-forming toxin in vivo. (
  • Pneumolysin, an important virulence factor of the human pathogen Streptococcus pneumoniae, is a pore-forming toxin which also possesses the ability to activate the complement system directly. (
  • Toxin - One of a number of poisons produced by certain plants, animals, and bacteria. (
  • The term toxin is frequently used to refer specifically to a particular protein produced by some higher plants, animals and pathogenic (disease causing) bacteria. (
  • bacterial diseases - Diseases caused by bacteria. (
  • Michel R. Popoff is Head of the Anaerobic Bacteria and Toxins Unit and the Director of the National Reference Center for Anaerobic Bacteria and Botulism at Pasteur Institute, Paris. (
  • If this happens, the bacteria can release toxin. (
  • Many bacteria inject toxins into human cells using a secretion system that resembles a molecular syringe. (
  • Some bacterial toxins, produced by pathogenic bacteria, have the same activity. (
  • Pneumolysin is a 53 kDa bacterial protein toxin that inserts into eukaryotic membranes where it self-associates to form pores in the membrane. (
  • We demonstrated that ebselen acts through inhibition of protein synthesis and subsequently inhibited toxin production in MRSA. (
  • Ebselen 1% and 2% significantly reduced the bacterial load and the levels of the pro-inflammatory cytokines tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), interleukin-1 beta (IL-1β), and monocyte chemo attractant protein-1 (MCP-1) in MRSA USA300 skin lesions. (
  • Studies on the structure and mechanism of a bacterial protein toxin by analytical ultracentrifugation and small-angle neutron scattering. (
  • We propose that the changes in membrane structure on toxin attack which we have observed are related to the mechanism by which pneumolysin forms pores and provide an important perspective on protein/membrane interactions in general. (
  • There are seven known classes of TA systems depending on the nature of the antitoxin and its mode of action on the toxin, with the toxin always being a protein. (
  • the SocB toxin is responsible for the essentiality of the clpX and clpP genes in this bacterium, and the SocA antitoxin serves as an adaptor protein to address the SocB toxin to the ClpXP AAA + protease. (
  • And so without this regulatory protein, C three B is able to bind to the bacterial cell surface and then it will associate with other complement system proteins. (
  • And so notice that the regulatory protein is a protein on the surface of specifically serum resistant bacterial cells. (
  • Until now, however, scientists have been able to track down only a few of the proteins that interact with bacterial toxins in infected human cells. (
  • Surprisingly, the toxins are not optimally adapted to the structures of human proteins," Dr. Matthias Selbach of MDC explained. (
  • A single bacterial toxin seems to function like a master key that can access different host cell proteins in parallel", Dr. Selbach said. (
  • Alpha-toxin has been shown to play a role in pathogenesis of disease, as hly knockout strains show reductions in invasiveness and virulence. (
  • The resulting active toxin would then target essential cellular processes and inhibit bacterial growth. (
  • In Type I systems, the antitoxin is a small anti-sense RNA that forms a duplex with the toxin's mRNA to inhibit toxin production ( Brantl, 2012 ). (
  • TA systems are organized into operons and are widely distributed throughout the bacterial genome ( Van Melderen, 2010 ). (
  • Several bacterial pathogens use toxins to manipulate human host cells, ultimately disturbing cellular signal transduction. (
  • Also, introduction of alpha-toxin specific antibodies into an unimmunized animal protects against subsequent infection. (
  • Whether the infection is viral or bacterial, the body fights it by raising the cat's internal body temperature by activating their immune system. (
  • Sores on the cornea most often caused by a serious bacterial or viral infection. (
  • It may be related to an autoimmune disorder, infection, or exposure to toxins. (
  • Even transient bacteremia can be a serious matter for those with prosthetic devices (which can serve as foci for infection) or for those with debilitating medical conditions that increase susceptibility to bacterial invasion. (
  • Folliculitis and Skin Abscesses Folliculitis and skin abscesses are pus-filled pockets in the skin resulting from bacterial infection. (
  • Before the 20th century, biological warfare took three main forms: (1) deliberate poisoning of food and water with infectious or toxic material, (2) use of microorganisms or toxins in some form of weapon system, and (3) use of biologically inoculated fabrics. (
  • Biological weapons include any organism or toxin found in nature that can be used to incapacitate, kill, or otherwise impede an adversary. (
  • His laboratory is focused on Clostridium toxins through genetic and biological activity analysis and has investigated the regulation of toxin synthesis in Clostridium botulinum and Clostridium tetani . (
  • Bacterial toxins are frequently the major cause of the pathogenicity of the organism in question. (
  • A ubiquitous organism, S pyogenes is the most common bacterial cause of acute pharyngitis , accounting for 15-30% of cases in children and 5-10% of cases in adults. (
  • The overall trend was a thinning of the liposome surface on toxin attack, which was countered by the formation of localized structures thicker than the liposome bilayer itself, in a manner dependent on pneumolysin concentration. (
  • It has been proposed that toxin activation or expression of the TA operon could rely on the degradation of generally less stable antitoxins by cellular proteases. (
  • Airborne dusts generated during removal of the cap of moldy silage from silos were analyzed for Gram negative bacterial endotoxins. (
  • The authors conclude that Gram negative bacterial endotoxins occur in silage and its related airborne dust. (
  • Low concentrations of toxin bind to specific, but unidentified, cell surface receptors and form the heptameric pores. (
  • Alpha-toxin, also known as alpha-hemolysin (Hla), is the major cytotoxic agent released by bacterium Staphylococcus aureus and the first identified member of the pore forming beta-barrel toxin family. (
  • This process involves the initial interaction between toxin and membrane, followed by interaction between toxin monomers. (
  • This structure allows the toxin to perform its major function, development of pores in the cellular membrane, eventually causing cell death. (
  • Two important aspects of the pore-forming activity of pneumolysin are therefore the effect of the toxin on bilayer membrane structure and the nature of the self-association into oligomers undergone by it. (
  • And of course activation of the complement system is going to lead to either uh inflammation optimization or membrane attack complex is and this bacterial cell would be eliminated. (
  • Additionally, CDC is working with state health departments to learn more about suspect cases and obtain bacterial isolates for further characterization. (
  • Alpha-toxin is also one of the key virulence factors in S. aureus pneumonia. (
  • Recent research has shown that immunization with a mutant form of alpha-toxin that is no longer able to form pores protects against S. aureus pneumonia in mice. (
  • subsequent activation of pneumolysin in situ brought about changes in liposome structure similar to those seen in the presence of active toxin. (
  • In addition to the effect that interaction with antitoxin has on the amount of free toxin in the cell, the concentration of toxin is also controlled with negative regulation at the transcriptional level. (
  • Recently, studies have shown that alpha-toxin plays a role in inducing apoptosis in certain human immune cells. (
  • Incubation of T-cells, monocytes, and peripheral blood lymphocytes with either purified alpha-toxin or S. aureus cell lysate resulted in the induction of apoptosis via the intrinsic death pathway. (
  • In the same study, alpha toxin was shown to activate caspase 8 and caspase 9, which in turn activate caspase 3, which causes massive DNA degradation and apoptosis. (
  • Toxin - This article is about the class of poisonous substances. (
  • Higher concentrations result in the toxin absorbing nonspecifically to the lipid bilayer and forming large, Ca2+ permissive pores. (
  • Instead of nonspecific antibiotic therapy, new drugs could target the signaling mechanisms which are disrupted by the bacterial toxins. (
  • Bacteremia can often be anticipated in individuals undergoing high-risk surgical procedures, with preventive antibiotic therapy being given to forestall extensive bacterial invasion of the bloodstream. (
  • Although they are widespread in bacterial chromosomes and in mobile genetic elements, their cellular functions and activation mechanisms remain largely unknown. (
  • Rhabdomyolysis is a condition when there is a severe muscle breakdown with the release into the circulation of muscle breakdown toxins which can cause kidney damage," Kaldas said. (
  • The level of alpha-toxin expressed by a particular strain of S. aureus directly correlates with the virulence of the strain. (
  • Epidemiology and virulence of Campylobacter concisus as an emerging bacterial pathogen. (
  • An important component of this work will be to develop the experimental tools necessary to monitor toxin-target binding and transcriptional regulation in real-time. (
  • Toxin-antitoxin (TA) systems are small genetic elements composed of a noxious toxin and a counteracting cognate antitoxin. (
  • Classical TA systems are small genetic modules composed of a deleterious toxin and an antitoxin that neutralizes the effects of the toxin. (
  • Despite being found throughout the prokaryotic kingdom, toxin-antitoxin (TA) systems remain mysterious with regard to their precise role in biology. (
  • Generally, TA systems are composed of two genes, one of which has a toxic effect on the cell and the other which prevents the toxin from reaching its target. (
  • Students will develop detailed mathematical models of TA systems and explore in silico toxin dynamics as well as the effect of redundancy in feedback. (
  • We hang both the original SPATT and the new SPATT from the Santa Cruz Wharf to track the full complement of lipophilic and hydrophilic algal toxins," said UCSC graduate student Jenny Lane. (
  • -- A new tool for tracking algal toxins is under development at UC Santa Cruz. (
  • toxin - A naturally produced poisonous substance that will damage or kill other cells. (
  • Cultures of human lung epithelial cells incubated with anti-alpha-toxin and infected with S. aureus showed marked reductions in cellular damage when compared to control cells. (
  • A current limitation of SPATT is that it does not measure toxin levels within algal cells. (
  • Instead, it measures that small fraction of a toxin that leaks from cells into water. (
  • The dosage of toxin can result in two different modes of activity. (
  • This activity was inhibited when two different anti-alpha-toxin antibodies were introduced. (
  • Scientists envision hanging the resin-filled sachets off piers and wharfs in California to continuously track nearshore toxin levels, similar to what is being done through sentinel "mussel watch" programs. (
  • We are studying the structures of bacterial toxins that form ion channels and catalyze macromolecule transport across membranes. (
  • Applying a method developed by Professor Matthias Mann of the MPI, the scientists succeeded for the first time in systematically investigating the cellular target sites of the bacterial toxins. (
  • Mussels, oysters, and fishes (such as sardines and anchovies) that feed on algae can accumulate the toxin, causing poisoning in animals that eat them. (