Virulence: The degree of pathogenicity within a group or species of microorganisms or viruses as indicated by case fatality rates and/or the ability of the organism to invade the tissues of the host. The pathogenic capacity of an organism is determined by its VIRULENCE FACTORS.Bacterial Proteins: Proteins found in any species of bacterium.Gene Expression Regulation, Bacterial: Any of the processes by which cytoplasmic or intercellular factors influence the differential control of gene action in bacteria.Genes, Bacterial: The functional hereditary units of BACTERIA.Molecular Sequence Data: 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.Mutation: 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.Gene Deletion: A genetic rearrangement through loss of segments of DNA or RNA, bringing sequences which are normally separated into close proximity. This deletion may be detected using cytogenetic techniques and can also be inferred from the phenotype, indicating a deletion at one specific locus.Bacterial Adhesion: Physicochemical property of fimbriated (FIMBRIAE, BACTERIAL) and non-fimbriated bacteria of attaching to cells, tissue, and nonbiological surfaces. It is a factor in bacterial colonization and pathogenicity.Plant Diseases: Diseases of plants.DNA, Bacterial: Deoxyribonucleic acid that makes up the genetic material of bacteria.Host-Pathogen Interactions: The interactions between a host and a pathogen, usually resulting in disease.Quorum Sensing: A phenomenon where microorganisms communicate and coordinate their behavior by the accumulation of signaling molecules. A reaction occurs when a substance accumulates to a sufficient concentration. This is most commonly seen in bacteria.Escherichia coli Infections: Infections with bacteria of the species ESCHERICHIA COLI.Hemolysin Proteins: 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.Genomic Islands: Distinct units in some bacterial, bacteriophage or plasmid GENOMES that are types of MOBILE GENETIC ELEMENTS. Encoded in them are a variety of fitness conferring genes, such as VIRULENCE FACTORS (in "pathogenicity islands or islets"), ANTIBIOTIC RESISTANCE genes, or genes required for SYMBIOSIS (in "symbiosis islands or islets"). They range in size from 10 - 500 kilobases, and their GC CONTENT and CODON usage differ from the rest of the genome. They typically contain an INTEGRASE gene, although in some cases this gene has been deleted resulting in "anchored genomic islands".Bacterial Toxins: 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.Adhesins, Bacterial: Cell-surface components or appendages of bacteria that facilitate adhesion (BACTERIAL ADHESION) to other cells or to inanimate surfaces. Most fimbriae (FIMBRIAE, BACTERIAL) of gram-negative bacteria function as adhesins, but in many cases it is a minor subunit protein at the tip of the fimbriae that is the actual adhesin. In gram-positive bacteria, a protein or polysaccharide surface layer serves as the specific adhesin. What is sometimes called polymeric adhesin (BIOFILMS) is distinct from protein adhesin.Plasmids: Extrachromosomal, usually CIRCULAR DNA molecules that are self-replicating and transferable from one organism to another. They are found in a variety of bacterial, archaeal, fungal, algal, and plant species. They are used in GENETIC ENGINEERING as CLONING VECTORS.Yersinia pestis: The etiologic agent of PLAGUE in man, rats, ground squirrels, and other rodents.Mice, Inbred BALB CEscherichia coli: 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.Bacterial Outer Membrane Proteins: Proteins isolated from the outer membrane of Gram-negative bacteria.Genome, Bacterial: The genetic complement of a BACTERIA as represented in its DNA.Lethal Dose 50: The dose amount of poisonous or toxic substance or dose of ionizing radiation required to kill 50% of the tested population.Amino Acid Sequence: 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.Mutagenesis, Insertional: Mutagenesis where the mutation is caused by the introduction of foreign DNA sequences into a gene or extragenic sequence. This may occur spontaneously in vivo or be experimentally induced in vivo or in vitro. Proviral DNA insertions into or adjacent to a cellular proto-oncogene can interrupt GENETIC TRANSLATION of the coding sequences or interfere with recognition of regulatory elements and cause unregulated expression of the proto-oncogene resulting in tumor formation.Salmonella typhimurium: A serotype of Salmonella enterica that is a frequent agent of Salmonella gastroenteritis in humans. It also causes PARATYPHOID FEVER.Sequence Analysis, DNA: A multistage process that includes cloning, physical mapping, subcloning, determination of the DNA SEQUENCE, and information analysis.Genetic Complementation Test: A test used to determine whether or not complementation (compensation in the form of dominance) will occur in a cell with a given mutant phenotype when another mutant genome, encoding the same mutant phenotype, is introduced into that cell.Base Sequence: The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.Streptococcus pyogenes: A species of gram-positive, coccoid bacteria isolated from skin lesions, blood, inflammatory exudates, and the upper respiratory tract of humans. It is a group A hemolytic Streptococcus that can cause SCARLET FEVER and RHEUMATIC FEVER.Pseudomonas aeruginosa: 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.Cryptococcus neoformans: A species of the fungus CRYPTOCOCCUS. Its teleomorph is Filobasidiella neoformans.Escherichia coli Proteins: Proteins obtained from ESCHERICHIA COLI.Phylogeny: The relationships of groups of organisms as reflected by their genetic makeup.Vibrio cholerae: The etiologic agent of CHOLERA.Antigens, Bacterial: Substances elaborated by bacteria that have antigenic activity.Candida albicans: A unicellular budding fungus which is the principal pathogenic species causing CANDIDIASIS (moniliasis).Disease Models, Animal: Naturally occurring or experimentally induced animal diseases with pathological processes sufficiently similar to those of human diseases. They are used as study models for human diseases.Shigella flexneri: A bacterium which is one of the etiologic agents of bacillary dysentery (DYSENTERY, BACILLARY) and sometimes of infantile gastroenteritis.Listeria monocytogenes: A species of gram-positive, rod-shaped bacteria widely distributed in nature. It has been isolated from sewage, soil, silage, and from feces of healthy animals and man. Infection with this bacterium leads to encephalitis, meningitis, endocarditis, and abortion.Yersinia pseudotuberculosis: A human and animal pathogen causing mesenteric lymphadenitis, diarrhea, and bacteremia.Staphylococcus aureus: 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.Yersinia enterocolitica: A species of the genus YERSINIA, isolated from both man and animal. It is a frequent cause of bacterial gastroenteritis in children.Streptococcal Infections: Infections with bacteria of the genus STREPTOCOCCUS.Serotyping: Process of determining and distinguishing species of bacteria or viruses based on antigens they share.Fungal Proteins: Proteins found in any species of fungus.Fimbriae, Bacterial: Thin, hairlike appendages, 1 to 20 microns in length and often occurring in large numbers, present on the cells of gram-negative bacteria, particularly Enterobacteriaceae and Neisseria. Unlike flagella, they do not possess motility, but being protein (pilin) in nature, they possess antigenic and hemagglutinating properties. They are of medical importance because some fimbriae mediate the attachment of bacteria to cells via adhesins (ADHESINS, BACTERIAL). Bacterial fimbriae refer to common pili, to be distinguished from the preferred use of "pili", which is confined to sex pili (PILI, SEX).Plague: An acute infectious disease caused by YERSINIA PESTIS that affects humans, wild rodents, and their ectoparasites. This condition persists due to its firm entrenchment in sylvatic rodent-flea ecosystems throughout the world. Bubonic plague is the most common form.Bacterial Capsules: An envelope of loose gel surrounding a bacterial cell which is associated with the virulence of pathogenic bacteria. Some capsules have a well-defined border, whereas others form a slime layer that trails off into the medium. Most capsules consist of relatively simple polysaccharides but there are some bacteria whose capsules are made of polypeptides.Phenotype: The outward appearance of the individual. It is the product of interactions between genes, and between the GENOTYPE and the environment.Regulon: In eukaryotes, a genetic unit consisting of a noncontiguous group of genes under the control of a single regulator gene. In bacteria, regulons are global regulatory systems involved in the interplay of pleiotropic regulatory domains and consist of several OPERONS.Hyphae: Microscopic threadlike filaments in FUNGI that are filled with a layer of protoplasm. Collectively, the hyphae make up the MYCELIUM.Microbial Viability: Ability of a microbe to survive under given conditions. This can also be related to a colony's ability to replicate.DNA Transposable Elements: Discrete segments of DNA which can excise and reintegrate to another site in the genome. Most are inactive, i.e., have not been found to exist outside the integrated state. DNA transposable elements include bacterial IS (insertion sequence) elements, Tn elements, the maize controlling elements Ac and Ds, Drosophila P, gypsy, and pogo elements, the human Tigger elements and the Tc and mariner elements which are found throughout the animal kingdom.Salmonella Infections, Animal: Infections in animals with bacteria of the genus SALMONELLA.Operon: In bacteria, a group of metabolically related genes, with a common promoter, whose transcription into a single polycistronic MESSENGER RNA is under the control of an OPERATOR REGION.Yersinia pseudotuberculosis Infections: Infections with bacteria of the species YERSINIA PSEUDOTUBERCULOSIS.Colony Count, Microbial: Enumeration by direct count of viable, isolated bacterial, archaeal, or fungal CELLS or SPORES capable of growth on solid CULTURE MEDIA. The method is used routinely by environmental microbiologists for quantifying organisms in AIR; FOOD; and WATER; by clinicians for measuring patients' microbial load; and in antimicrobial drug testing.Fimbriae Proteins: Proteins that are structural components of bacterial fimbriae (FIMBRIAE, BACTERIAL) or sex pili (PILI, SEX).Macrophages: 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.)Vibrio Infections: Infections with bacteria of the genus VIBRIO.Gene Knockout Techniques: Techniques to alter a gene sequence that result in an inactivated gene, or one in which the expression can be inactivated at a chosen time during development to study the loss of function of a gene.Yersinia: A genus of gram-negative, facultatively anaerobic rod- to coccobacillus-shaped bacteria that occurs in a broad spectrum of habitats.Polymerase Chain Reaction: In vitro method for producing large amounts of specific DNA or RNA fragments of defined length and sequence from small amounts of short oligonucleotide flanking sequences (primers). The essential steps include thermal denaturation of the double-stranded target molecules, annealing of the primers to their complementary sequences, and extension of the annealed primers by enzymatic synthesis with DNA polymerase. The reaction is efficient, specific, and extremely sensitive. Uses for the reaction include disease diagnosis, detection of difficult-to-isolate pathogens, mutation analysis, genetic testing, DNA sequencing, and analyzing evolutionary relationships.Yersinia Infections: Infections with bacteria of the genus YERSINIA.Cell Line: Established cell cultures that have the potential to propagate indefinitely.Species Specificity: The restriction of a characteristic behavior, anatomical structure or physical system, such as immune response; metabolic response, or gene or gene variant to the members of one species. It refers to that property which differentiates one species from another but it is also used for phylogenetic levels higher or lower than the species.Siderophores: Low-molecular-weight compounds produced by microorganisms that aid in the transport and sequestration of ferric iron. (The Encyclopedia of Molecular Biology, 1994)Salmonella: A genus of gram-negative, facultatively anaerobic, rod-shaped bacteria that utilizes citrate as a sole carbon source. It is pathogenic for humans, causing enteric fevers, gastroenteritis, and bacteremia. Food poisoning is the most common clinical manifestation. Organisms within this genus are separated on the basis of antigenic characteristics, sugar fermentation patterns, and bacteriophage susceptibility.Bacterial Secretion Systems: In GRAM NEGATIVE BACTERIA, multiprotein complexes that function to translocate pathogen protein effector molecules across the bacterial cell envelope, often directly into the host. These effectors are involved in producing surface structures for adhesion, bacterial motility, manipulation of host functions, modulation of host defense responses, and other functions involved in facilitating survival of the pathogen. Several of the systems have homologous components functioning similarly in GRAM POSITIVE BACTERIA.Vibrio vulnificus: A species of halophilic bacteria in the genus VIBRIO, which lives in warm SEAWATER. It can cause infections in those who eat raw contaminated seafood or have open wounds exposed to seawater.Cryptococcosis: Infection with a fungus of the species CRYPTOCOCCUS NEOFORMANS.Pseudomonas Infections: Infections with bacteria of the genus PSEUDOMONAS.Rhodococcus equi: A species of RHODOCOCCUS found in soil, herbivore dung, and in the intestinal tract of cows, horses, sheep, and pigs. It causes bronchopneumonia in foals and can be responsible for infection in humans compromised by immunosuppressive drug therapy, lymphoma, or AIDS.Gene Expression Regulation, Fungal: Any of the processes by which nuclear, cytoplasmic, or intercellular factors influence the differential control of gene action in fungi.Staphylococcal Infections: Infections with bacteria of the genus STAPHYLOCOCCUS.Streptolysins: Exotoxins produced by certain strains of streptococci, particularly those of group A (STREPTOCOCCUS PYOGENES), that cause HEMOLYSIS.Vibrio: A genus of VIBRIONACEAE, made up of short, slightly curved, motile, gram-negative rods. Various species produce cholera and other gastrointestinal disorders as well as abortion in sheep and cattle.Host-Parasite Interactions: The relationship between an invertebrate and another organism (the host), one of which lives at the expense of the other. Traditionally excluded from definition of parasites are pathogenic BACTERIA; FUNGI; VIRUSES; and PLANTS; though they may live parasitically.Poultry Diseases: Diseases of birds which are raised as a source of meat or eggs for human consumption and are usually found in barnyards, hatcheries, etc. The concept is differentiated from BIRD DISEASES which is for diseases of birds not considered poultry and usually found in zoos, parks, and the wild.Polysaccharides, Bacterial: Polysaccharides found in bacteria and in capsules thereof.Cloning, Molecular: 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.Anti-Bacterial Agents: Substances that reduce the growth or reproduction of BACTERIA.4-Butyrolactone: One of the FURANS with a carbonyl thereby forming a cyclic lactone. It is an endogenous compound made from gamma-aminobutyrate and is the precursor of gamma-hydroxybutyrate. It is also used as a pharmacological agent and solvent.Genotype: The genetic constitution of the individual, comprising the ALLELES present at each GENETIC LOCUS.Candidiasis: Infection with a fungus of the genus CANDIDA. It is usually a superficial infection of the moist areas of the body and is generally caused by CANDIDA ALBICANS. (Dorland, 27th ed)Gene Expression Profiling: The determination of the pattern of genes expressed at the level of GENETIC TRANSCRIPTION, under specific circumstances or in a specific cell.Pseudomonas syringae: A species of gram-negative, fluorescent, phytopathogenic bacteria in the genus PSEUDOMONAS. It is differentiated into approximately 50 pathovars with different plant pathogenicities and host specificities.Sequence Alignment: 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.Francisella tularensis: The etiologic agent of TULAREMIA in man and other warm-blooded animals.Serial Passage: Inoculation of a series of animals or in vitro tissue with an infectious bacterium or virus, as in VIRULENCE studies and the development of vaccines.Sequence Homology, Amino Acid: The degree of similarity between sequences of amino acids. This information is useful for the analyzing genetic relatedness of proteins and species.Genetic Variation: Genotypic differences observed among individuals in a population.Cytotoxins: 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.Fish Diseases: Diseases of freshwater, marine, hatchery or aquarium fish. This term includes diseases of both teleosts (true fish) and elasmobranchs (sharks, rays and skates).Hemolysis: The destruction of ERYTHROCYTES by many different causal agents such as antibodies, bacteria, chemicals, temperature, and changes in tonicity.Drug Resistance, Bacterial: The ability of bacteria to resist or to become tolerant to chemotherapeutic agents, antimicrobial agents, or antibiotics. This resistance may be acquired through gene mutation or foreign DNA in transmissible plasmids (R FACTORS).Mutagenesis: Process of generating a genetic MUTATION. It may occur spontaneously or be induced by MUTAGENS.Bacillus anthracis: A species of bacteria that causes ANTHRAX in humans and animals.RNA, Bacterial: Ribonucleic acid in bacteria having regulatory and catalytic roles as well as involvement in protein synthesis.Iron: A metallic element with atomic symbol Fe, atomic number 26, and atomic weight 55.85. It is an essential constituent of HEMOGLOBINS; CYTOCHROMES; and IRON-BINDING PROTEINS. It plays a role in cellular redox reactions and in the transport of OXYGEN.Blood Bactericidal Activity: The natural bactericidal property of BLOOD due to normally occurring antibacterial substances such as beta lysin, leukin, etc. This activity needs to be distinguished from the bactericidal activity contained in a patient's serum as a result of antimicrobial therapy, which is measured by a SERUM BACTERICIDAL TEST.Xanthomonas: A genus in the family XANTHOMONADACEAE whose cells produce a yellow pigment (Gr. xanthos - yellow). It is pathogenic to plants.Culture Media: Any liquid or solid preparation made specifically for the growth, storage, or transport of microorganisms or other types of cells. The variety of media that exist allow for the culturing of specific microorganisms and cell types, such as differential media, selective media, test media, and defined media. Solid media consist of liquid media that have been solidified with an agent such as AGAR or GELATIN.Ascomycota: A phylum of fungi which have cross-walls or septa in the mycelium. The perfect state is characterized by the formation of a saclike cell (ascus) containing ascospores. Most pathogenic fungi with a known perfect state belong to this phylum.Phagocytosis: The engulfing and degradation of microorganisms; other cells that are dead, dying, or pathogenic; and foreign particles by phagocytic cells (PHAGOCYTES).Open Reading Frames: A sequence of successive nucleotide triplets that are read as CODONS specifying AMINO ACIDS and begin with an INITIATOR CODON and end with a stop codon (CODON, TERMINATOR).Cell Wall: The outermost layer of a cell in most PLANTS; BACTERIA; FUNGI; and ALGAE. The cell wall is usually a rigid structure that lies external to the CELL MEMBRANE, and provides a protective barrier against physical or chemical agents.Transcription, Genetic: The biosynthesis of RNA carried out on a template of DNA. The biosynthesis of DNA from an RNA template is called REVERSE TRANSCRIPTION.Streptococcus pneumoniae: A gram-positive organism found in the upper respiratory tract, inflammatory exudates, and various body fluids of normal and/or diseased humans and, rarely, domestic animals.Pectobacterium chrysanthemi: A species of gram-negative, facultatively anaerobic, rod-shaped bacteria that causes vascular wilts on a wide range of plant species. It was formerly named Erwinia chrysanthemi.Multigene Family: A set of genes descended by duplication and variation from some ancestral gene. Such genes may be clustered together on the same chromosome or dispersed on different chromosomes. Examples of multigene families include those that encode the hemoglobins, immunoglobulins, histocompatibility antigens, actins, tubulins, keratins, collagens, heat shock proteins, salivary glue proteins, chorion proteins, cuticle proteins, yolk proteins, and phaseolins, as well as histones, ribosomal RNA, and transfer RNA genes. The latter three are examples of reiterated genes, where hundreds of identical genes are present in a tandem array. (King & Stanfield, A Dictionary of Genetics, 4th ed)Escherichia coli O157: A verocytotoxin-producing serogroup belonging to the O subfamily of Escherichia coli which has been shown to cause severe food-borne disease. A strain from this serogroup, serotype H7, which produces SHIGA TOXINS, has been linked to human disease outbreaks resulting from contamination of foods by E. coli O157 from bovine origin.Prophages: Genomes of temperate BACTERIOPHAGES integrated into the DNA of their bacterial host cell. The prophages can be duplicated for many cell generations until some stimulus induces its activation and virulence.Aspergillus fumigatus: A species of imperfect fungi from which the antibiotic fumigatin is obtained. Its spores may cause respiratory infection in birds and mammals.Urinary Tract Infections: Inflammatory responses of the epithelium of the URINARY TRACT to microbial invasions. They are often bacterial infections with associated BACTERIURIA and PYURIA.Flagella: A whiplike motility appendage present on the surface cells. Prokaryote flagella are composed of a protein called FLAGELLIN. Bacteria can have a single flagellum, a tuft at one pole, or multiple flagella covering the entire surface. In eukaryotes, flagella are threadlike protoplasmic extensions used to propel flagellates and sperm. Flagella have the same basic structure as CILIA but are longer in proportion to the cell bearing them and present in much smaller numbers. (From King & Stansfield, A Dictionary of Genetics, 4th ed)Pyocyanine: Antibiotic pigment produced by Pseudomonas aeruginosa.Exotoxins: Toxins produced, especially by bacterial or fungal cells, and released into the culture medium or environment.Aeromonas hydrophila: A species of gram-negative, facultatively anaerobic, rod-shaped bacteria that may be pathogenic for frogs, fish, and mammals, including man. In humans, cellulitis and diarrhea can result from infection with this organism.Mycobacterium tuberculosis: A species of gram-positive, aerobic bacteria that produces TUBERCULOSIS in humans, other primates, CATTLE; DOGS; and some other animals which have contact with humans. Growth tends to be in serpentine, cordlike masses in which the bacilli show a parallel orientation.Lycopersicon esculentum: A plant species of the family SOLANACEAE, native of South America, widely cultivated for their edible, fleshy, usually red fruit.Transcription Factors: Endogenous substances, usually proteins, which are effective in the initiation, stimulation, or termination of the genetic transcription process.Streptococcus suis: A species of STREPTOCOCCUS isolated from pigs. It is a pathogen of swine but rarely occurs in humans.Ralstonia solanacearum: A species of Ralstonia previously classed in the genera PSEUDOMONAS and BURKHOLDERIA. It is an important plant pathogen.Enterohemorrhagic Escherichia coli: Strains of ESCHERICHIA COLI that are a subgroup of SHIGA-TOXIGENIC ESCHERICHIA COLI. They cause non-bloody and bloody DIARRHEA; HEMOLYTIC UREMIC SYNDROME; and hemorrhagic COLITIS. An important member of this subgroup is ESCHERICHIA COLI O157-H7.Hemagglutinins: Agents that cause agglutination of red blood cells. They include antibodies, blood group antigens, lectins, autoimmune factors, bacterial, viral, or parasitic blood agglutinins, etc.Salmonella Infections: Infections with bacteria of the genus SALMONELLA.Porphyromonas gingivalis: A species of gram-negative, anaerobic, rod-shaped bacteria originally classified within the BACTEROIDES genus. This bacterium produces a cell-bound, oxygen-sensitive collagenase and is isolated from the human mouth.Oligonucleotide Array Sequence Analysis: Hybridization of a nucleic acid sample to a very large set of OLIGONUCLEOTIDE PROBES, which have been attached individually in columns and rows to a solid support, to determine a BASE SEQUENCE, or to detect variations in a gene sequence, GENE EXPRESSION, or for GENE MAPPING.Cholera: An acute diarrheal disease endemic in India and Southeast Asia whose causative agent is VIBRIO CHOLERAE. This condition can lead to severe dehydration in a matter of hours unless quickly treated.Diarrhea: An increased liquidity or decreased consistency of FECES, such as running stool. Fecal consistency is related to the ratio of water-holding capacity of insoluble solids to total water, rather than the amount of water present. Diarrhea is not hyperdefecation or increased fecal weight.Trans-Activators: Diffusible gene products that act on homologous or heterologous molecules of viral or cellular DNA to regulate the expression of proteins.Gene Transfer, Horizontal: The naturally occurring transmission of genetic information between organisms, related or unrelated, circumventing parent-to-offspring transmission. Horizontal gene transfer may occur via a variety of naturally occurring processes such as GENETIC CONJUGATION; GENETIC TRANSDUCTION; and TRANSFECTION. It may result in a change of the recipient organism's genetic composition (TRANSFORMATION, GENETIC).Chickens: Common name for the species Gallus gallus, the domestic fowl, in the family Phasianidae, order GALLIFORMES. It is descended from the red jungle fowl of SOUTHEAST ASIA.Enterococcus faecalis: A species of gram-positive, coccoid bacteria commonly isolated from clinical specimens and the human intestinal tract. Most strains are nonhemolytic.Pectobacterium carotovorum: A species of gram-negative, facultatively anaerobic, rod-shaped bacteria that causes rotting, particularly of storage tissues, of a wide variety of plants and causes a vascular disease in CARROTS; and POTATO plants.Bacterial Typing Techniques: Procedures for identifying types and strains of bacteria. The most frequently employed typing systems are BACTERIOPHAGE TYPING and SEROTYPING as well as bacteriocin typing and biotyping.Sigma Factor: A protein which is a subunit of RNA polymerase. It effects initiation of specific RNA chains from DNA.HomoserinePlant Tumors: A localized proliferation of plant tissue forming a swelling or outgrowth, commonly with a characteristic shape and unlike any organ of the normal plant. Plant tumors or galls usually form in response to the action of a pathogen or a pest. (Holliday, P., A Dictionary of Plant Pathology, 1989, p330)Chromosomes, Bacterial: Structures within the nucleus of bacterial cells consisting of or containing DNA, which carry genetic information essential to the cell.Salmonella enterica: A subgenus of Salmonella containing several medically important serotypes. The habitat for the majority of strains is warm-blooded animals.Swine: Any of various animals that constitute the family Suidae and comprise stout-bodied, short-legged omnivorous mammals with thick skin, usually covered with coarse bristles, a rather long mobile snout, and small tail. Included are the genera Babyrousa, Phacochoerus (wart hogs), and Sus, the latter containing the domestic pig (see SUS SCROFA).Gram-Negative Bacterial Infections: Infections caused by bacteria that show up as pink (negative) when treated by the gram-staining method.Metarhizium: A mitosporic fungal genus in the family Clavicipitaceae. It has teleomorphs in the family Nectriaceae. Metarhizium anisopliae is used in PESTICIDES.Francisella: The lone genus of bacteria in the family Francisellaceae, frequently found in natural waters. It can be parasitic in humans, other MAMMALS; BIRDS; and ARTHROPODS.Animals, Outbred Strains: Animals that are generated from breeding two genetically dissimilar strains of the same species.Rabbits: 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.O Antigens: The lipopolysaccharide-protein somatic antigens, usually from gram-negative bacteria, important in the serological classification of enteric bacilli. The O-specific chains determine the specificity of the O antigens of a given serotype. O antigens are the immunodominant part of the lipopolysaccharide molecule in the intact bacterial cell. (From Singleton & Sainsbury, Dictionary of Microbiology and Molecular Biology, 2d ed)Sequence Deletion: Deletion of sequences of nucleic acids from the genetic material of an individual.Epithelial Cells: Cells that line the inner and outer surfaces of the body by forming cellular layers (EPITHELIUM) or masses. Epithelial cells lining the SKIN; the MOUTH; the NOSE; and the ANAL CANAL derive from ectoderm; those lining the RESPIRATORY SYSTEM and the DIGESTIVE SYSTEM derive from endoderm; others (CARDIOVASCULAR SYSTEM and LYMPHATIC SYSTEM) derive from mesoderm. Epithelial cells can be classified mainly by cell shape and function into squamous, glandular and transitional epithelial cells.Chicory: A thick-rooted perennial (Cichorium intybus) native to Europe but widely grown for its young leaves used as salad greens and for its roots, dried and ground-roasted, used to flavor or adulterate coffee. (From Webster, 3d ed)Vaccines, Attenuated: Live vaccines prepared from microorganisms which have undergone physical adaptation (e.g., by radiation or temperature conditioning) or serial passage in laboratory animal hosts or infected tissue/cell cultures, in order to produce avirulent mutant strains capable of inducing protective immunity.Beauveria: A mitosporic fungal genus. Teleomorphs are found in the family Clavicipitaceae and include Cordyceps bassiana. The species Beauveria bassiana is a common pathogen of ARTHROPODS and is used in PEST CONTROL.Legionella pneumophila: A species of gram-negative, aerobic bacteria that is the causative agent of LEGIONNAIRES' DISEASE. It has been isolated from numerous environmental sites as well as from human lung tissue, respiratory secretions, and blood.Viral Proteins: Proteins found in any species of virus.Lung: Either of the pair of organs occupying the cavity of the thorax that effect the aeration of the blood.Tularemia: A plague-like disease of rodents, transmissible to man. It is caused by FRANCISELLA TULARENSIS and is characterized by fever, chills, headache, backache, and weakness.Listeriosis: Infections with bacteria of the genus LISTERIA.Erwinia amylovora: A species of gram-negative bacteria, in the genus ERWINIA, causing a necrotic disease of plants.Mice, Inbred C57BLVirus Replication: The process of intracellular viral multiplication, consisting of the synthesis of PROTEINS; NUCLEIC ACIDS; and sometimes LIPIDS, and their assembly into a new infectious particle.Edwardsiella tarda: A species of EDWARDSIELLA distinguished by its hydrogen sulfide production. (From Bergey's Manual of Determinative Bacteriology, 9th ed)Recombination, Genetic: Production of new arrangements of DNA by various mechanisms such as assortment and segregation, CROSSING OVER; GENE CONVERSION; GENETIC TRANSFORMATION; GENETIC CONJUGATION; GENETIC TRANSDUCTION; or mixed infection of viruses.Adhesins, Escherichia coli: Thin, filamentous protein structures, including proteinaceous capsular antigens (fimbrial antigens), that mediate adhesion of E. coli to surfaces and play a role in pathogenesis. They have a high affinity for various epithelial cells.Bacterial Vaccines: Suspensions of attenuated or killed bacteria administered for the prevention or treatment of infectious bacterial disease.Aeromonas: A genus of gram-negative, facultatively anaerobic, rod-shaped bacteria that occurs singly, in pairs, or in short chains. Its organisms are found in fresh water and sewage and are pathogenic to humans, frogs, and fish.Acanthamoeba castellanii: A species of free-living soil amoebae in the family Acanthamoebidae. It can cause ENCEPHALITIS and KERATITIS in humans.DNA Primers: Short sequences (generally about 10 base pairs) of DNA that are complementary to sequences of messenger RNA and allow reverse transcriptases to start copying the adjacent sequences of mRNA. Primers are used extensively in genetic and molecular biology techniques.

*  2-for-1 bacterial virulence factor revealed | EurekAlert! Science News

Drugs that hobble the production of virulence factors, small molecules that help bacteria to establish an infection in a host, ... In Infectious Diseases he describes recent work on a target virulence factor. ... One class of virulence factors common to many pathogens is siderophores, small molecules whose job is to seek out iron in the ... Virulence factors allow bacteria to evade the human immune system, to infect tissues and cells and to establish a foothold ...

*  Is the virulence of HIV changing? A meta-analysis of trends in prognostic markers of HIV disease progression and transmission ...

... CONCLUSION:: Our results are consistent with increased virulence of HIV-1 over the course of the epidemic. Extrapolating over ... CONCLUSION:: Our results are consistent with increased virulence of HIV-1 over the course of the epidemic. Extrapolating over ... OBJECTIVE:: The potential for changing HIV-1 virulence has significant implications for the AIDS epidemic, including changing ...

*  NanoLuc® Luciferase: A Good Thing for Small Packages

... development in the world of influenza research-the construction of a luciferase reporter virus that does not affect virulence ... development in the world of influenza research-the construction of a luciferase reporter virus that does not affect virulence ...

*  Virulence Hashag Virulence Black Hand Printed T shirt | Fruugo

an Ideal gift for anyone interested in virulence Sizes are Small 35 - 37', Medium 38 - 40', Large 40 - 41', XL 44 - 46', XXL 47 ... Heavy Cotton Fruit of the Loom Virulence tshirt in BlackThe printing wont fade or crack even when tumble dried so your shirt ... Virulence Hashag Virulence Black Hand Printed T shirt has been added to your basket ... Virulence tshirt in Black. The printing wont fade or crack even when tumble dried so your shirt will stay as soft and silky for ...

*  Spanish Word for virulence | virulence in Spanish

Learn how to say virulence in Spanish with audio of a native Spanish speaker. ... Spanish word for virulence, including example sentences in both English and Spanish. ... English Word: virulence Spanish Word: virulencia Now you know how to say virulence in Spanish. :-) More Spanish - English ...

*  Homeostatic Interplay between Bacterial Cell-Cell Signaling and Iron in Virulence

Via negative and positive feedback loops, this bacterium processes the signaled information to regulate its virulence functions ... Our study sheds light on paradigmatic complex networks that maintain a homeostatic bacterial virulence response. ... to modulate its virulence functions by titrating the concentration of the small molecules HHQ and PQS in a manner that depends ... and homeostatically balance the production of the small molecules required for the activation of the MvfR virulence network. ...

*  Ecological and Evolutionary Science | mSphere

Despite both clinical and laboratory data that show increased virulence in field isolates of MDV-1 over the last half century, ... Genome Diversity, Recombination, and Virulence across the Major Lineages of Paracoccidioides. Characterization of genetic ... MDV-1 isolates tend to lose virulence during repeated cycles of replication in the laboratory, raising... ...

*  ASMscience | Mobile Genetic Elements

Although the virulence genes acquired as components of mobile elements may not have been subject to host regulatory processes ... However, a subset of virulence factors does not seem to confer any advantages on the bacterial hosts, so the forces underlying ... Mobile genetic elements have clearly distributed a diverse collection of virulence genes and thereby played essential roles in ... Finally, some plasmids, such as the large Yersinia virulence plasmid and the enterohemorrhagic Escherichia coli (EHEC) ...

*  Recent Articles | Virulence | The Scientist Magazine®

Researchers characterize a protein that could be key to the virus's virulence-and to developing a vaccine against the mosquito- ... technique could soon spur unprecedented insight into the role of bacterial epigenetics in the evolution of pathogen virulence. ...

*  'virulence factors' Protocols and Video...

Monitoring the Assembly of a Secreted Bacterial Virulence Factor Using Site-specific Crosslinking', 'A Murine Model of Group B ... Following in Real Time the Impact of Pneumococcal Virulence Factors in an Acute Mouse Pneumonia Model Using Bioluminescent ... The Madagascar Hissing Cockroach As an Alternative Non-Mammalian Animal Model to Investigate Virulence, Pathogenesis, and Drug ... Bacteria', 'Applying an Inducible Expression System to Study Interference of Bacterial Virulence Factors with Intracellular ... factors

*  Key to Virulence Protein Entry into Host Cells Found

... at Virginia Tech have discovered the region of a large family of virulence proteins in oomycete plant pathogens that enables ... The virulence proteins, including Avr1b, enter the soybean host where they suppress an important process in plant immunity ... A large family of virulence proteins in oomycete plant pathogens that enables the proteins to enter the cells of their hosts ... This protein region contains the amino acid sequence motifs RXLR and dEER and has the ability to carry the virulence proteins ...

*  European Commission : CORDIS : Programmes : Antimicrobial drug resistance and changes in virulence

European Commission

*  Entamoeba histolytica. Phagocytosis as a virulence factor. | JEM

The virulence of clone L-6 and strain HM1:IMSS was measured. The inoculum required to induce liver abscesses in 50% of the ... Phagocytosis as a virulence factor.. E Orozco, G Guarneros, A Martinez-Palomo, T Sánchez ... Virulence revertants were obtained by successive passage of L-6 trophozoites through the liver of young hamsters. The ... In this paper, we attempted to define the role of phagocytosis in the virulence of Entamoeba histolytica. We have isolated, ...

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*  British Library EThOS: Virulence determinants of Burkholderia pseudomallei.

Melioidosis; Tropical disease; Mutagenesis Microbiology Molecular biology Cytology Genetics

*  Brucella abortus S19 genome sequenced; points toward virulence genes | EurekAlert! Science News

Brucella abortus S19 genome sequenced; points toward virulence genes. Virginia Tech. Journal. PLOS ONE. Funder. National ... The researchers have discovered a group of 24 genes that are linked to virulence by making comparisons of the newly available ... The paper "Genome sequence of Brucella abortus vaccine strain S19 compared to virulent strains yields candidate virulence genes ... and comparative genomics narrowed down the search for Brucella virulence factors to a small group of genes. Of particular ...

*  Protein kinase A and fungal virulence

PKA: a pleiotropic regulator of virulence. Thus far, the contributions of PKA to fungal virulence have been categorized as ... Virulence. 2010;1:45-8. doi: 10.4161/viru.1.1.10320. [PMC free article] [PubMed] [Cross Ref] ... The second important virulence factor of C. neoformans to be discussed is melanin, which is believed to impart resistance to UV ... The glyoxylate cycle is required for fungal virulence. Nature. 2001;412:83-6. doi: 10.1038/35083594. [PubMed] [Cross Ref] ...

*  Polymerase may be key to flu's virulence | The Scientist Magazine®

This is not the only group to pinpoint mutations in polymerase as a potential factor in flu's virulence, said Robert Webster of ... They noted that mutations to the SC35M polymerase protein PB2 further increased the virulence of the already lethal strain. The ... The mutations pinpointed in the current study "probably are more important [to] the adaptation and the virulence in the mouse ... Polymerase may be key to flu's virulence. Model points to importance of polymerase activity in species jump ...

*  Citation Machine: Virulence format citation generator for dissertation (abstract)

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*  Virulency legal definition of virulency

What is virulency? Meaning of virulency as a legal term. What does virulency mean in law? ... Definition of virulency in the Legal Dictionary - by Free online English dictionary and encyclopedia. ... redirected from virulency). Also found in: Dictionary, Thesaurus, Medical, Encyclopedia, Wikipedia. virulent. adjective acerbus ... in which each assay could rapidly detect a specific pathogen and/or identify markers for drug resistance or virulency.. Rapid ...

*  Candida Virulence Properties and Adverse Clinical Outcomes in Neonatal Candidiasis | RTI

Individual isolates of C albicans and C parapsilosis were tested for virulence in 3 assays: phenotypic switching, adhesion, and ... Objective To determine whether premature infants with invasive Candida infection caused by strains with increased virulence ... Conclusion Individual isolates of Candida species vary in their virulence properties. Strains with higher virulence are ... Results Enhanced virulence was detected in 61% of invasive isolates of C albicans and 42% of invasive isolates of C ...

*  Virulence of Staphylococcus Lugdunensis in Severe Infections - Full Text View -

Virulence of Staphylococcus Lugdunensis in Severe Infections. Further study details as provided by University Hospital, ... Presence/absence of virulence factors [ Time Frame: Participants will be followed for the duration of hospital stay, an ... Virulence of Staphylococcus Lugdunensis in Severe Infections (VISLISI). This study has been completed. ... The following virulence factors will be searched for:. TSST-1, enterotoxins, leukotoxins, epidermolysins, beta-hemolysins, SCIN ..."Endocarditis"&rank=10

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Virulence: Virulence is, by MeSH definition, the degree of pathogenicity within a group or species of parasites as indicated by case fatality rates and/or the ability of the organism to invade the tissues of the host. The pathogenicity of an organism - its ability to cause disease - is determined by its virulence factors.Ferric uptake regulator family: In molecular biology, the ferric uptake regulator (FUR) family of proteins includes metal ion uptake regulator proteins. These are responsible for controlling the intracellular concentration of iron in many bacteria.Coles PhillipsSilent mutation: Silent mutations are mutations in DNA that do not significantly alter the phenotype of the organism in which they occur. Silent mutations can occur in non-coding regions (outside of genes or within introns), or they may occur within exons.Deletion (genetics)Gentamicin protection assay: The gentamicin protection assay or survival assay or invasion assay is a method used in microbiology. It is used to quantify the ability of pathogenic bacteria to invade eukaryotic cells.Fungicide use in the United States: A more accurate title for this page would be "Common plant pathogens to food crops in the United States".Haemolysin expression modulating protein family: In molecular biology, the haemolysin expression modulating protein family is a family of proteins. This family consists of haemolysin expression modulating protein (Hha) from Escherichia coli and its enterobacterial homologues, such as YmoA from Yersinia enterocolitica, and RmoA encoded on the R100 plasmid.AB toxin: The AB toxins are two-component protein complexes secreted by a number of pathogenic bacteria. They can be classified as Type III toxins because they interfere with internal cell function.Trimeric autotransporter adhesin: In molecular biology, trimeric autotransporter adhesins (TAAs), are proteins found on the outer membrane of Gram-negative bacteria. Bacteria use TAAs in order to infect their host cells via a process called cell adhesion.Triparental mating: Triparental mating is a form of Bacterial conjugation where a conjugative plasmid present in one bacterial strain assists the transfer of a mobilizable plasmid present in a second bacterial strain into a third bacterial strain. Plasmids are introduced into bacteria for such purposes as transformation, cloning, or transposon mutagenesis.LcrV: In molecular biology, LcrV is a protein found in Yersinia pestis and several other bacterial species. It forms part of the Yersinia pestis virulence protein factors that also includes all Yop's, this used to stand for Yersinia outer protein, but the name has been kept out of convention.List of strains of Escherichia coli: Escherichia coli is a well studied bacterium that was first identified by Theodor Escherich, after whom it was later named.Bacterial outer membraneGlobal microbial identifier: The genomic epidemiological database for global identification of microorganisms or global microbial identifier (GMI) is a platform for storing whole genome sequencing (WGS) data of microorganisms, for the identification of relevant genes and for the comparison of genomes to detect and track-and-trace infectious disease outbreaks and emerging pathogens. The database holds two types of information: 1) genomic information of microorganisms, linked to, 2) metadata of those microorganism such as epidemiological details.Median toxic dose: ==Introduction==Protein primary structure: The primary structure of a peptide or protein is the linear sequence of its amino acid structural units, and partly comprises its overall biomolecular structure. By convention, the primary structure of a protein is reported starting from the amino-terminal (N) end to the carboxyl-terminal (C) end.Signature-tagged mutagenesis: Signature-tagged mutagenesis (STM) is a genetic technique used to study gene function. Recent advances in genome sequencing have allowed us to catalogue a large variety of organisms' genomes, but the function of the genes they contain is still largely unknown.DNA sequencer: A DNA sequencer is a scientific instrument used to automate the DNA sequencing process. Given a sample of DNA, a DNA sequencer is used to determine the order of the four bases: G (guanine), C (cytosine), A (adenine) and T (thymine).Symmetry element: A symmetry element is a point of reference about which symmetry operations can take place. In particular, symmetry elements can be centers of inversion, axes of rotation and mirror planes.Trans-activating crRNA: In molecular biology, trans-activating crRNA (tracrRNA) is a small trans-encoded RNA. It was first discovered in the human pathogen Streptococcus pyogenes.GyrA RNA motif: The gyrA RNA motif is a conserved RNA structure identified by bioinformatics. The RNAs are present in multiple species of bacteria within the order Pseudomonadales.Cryptococcus neoformans: Cryptococcus neoformans is an encapsulated yeast and an obligate aerobe that can live in both plants and animals. Its teleomorph is Filobasidiella neoformans, a filamentous fungus belonging to the class Tremellomycetes.Escherichia coli (molecular biology): Escherichia coli (; commonly abbreviated E. coli) is a gammaproteobacterium commonly found in the lower intestine of warm-blooded organisms (endotherms).Branching order of bacterial phyla (Gupta, 2001): There are several models of the Branching order of bacterial phyla, one of these was proposed in 2001 by Gupta based on conserved indels or protein, termed "protein signatures", an alternative approach to molecular phylogeny. Some problematic exceptions and conflicts are present to these conserved indels, however, they are in agreement with several groupings of classes and phyla.El Tor: El Tor is the name given to a particular strain of the bacterium Vibrio cholerae, the causative agent of cholera. Also known as V.Erosio interdigitalis blastomycetica: Erosio interdigitalis blastomycetica is a skin condition caused by a Candida albicans infection, characterized by an oval-shaped area of macerated white skin on the web between and extending onto the sides of the fingers.Gross pathology: Gross pathology refers to macroscopic manifestations of disease in organs, tissues, and body cavities. The term is commonly used by anatomical pathologists to refer to diagnostically useful findings made during the gross examination portion of surgical specimen processing or an autopsy.Shigella flexneri: Shigella flexneri is a species of Gram-negative bacteria in the genus Shigella that can cause diarrhea in humans. Several different serogroups of Shigella are described; S.Listeria monocytogenes: Listeria monocytogenes is the bacterium that causes the infection listeriosis. It is a facultative anaerobic bacterium, capable of surviving in the presence or absence of oxygen.CDP-abequose synthase: CDP-abequose synthase (, rfbJ (gene)) is an enzyme with system name CDP-alpha-D-abequose:NADP+ 4-oxidoreductase. This enzyme catalyses the following chemical reactionSaPI: SaPIs (Staphylococcus aureus or superantigen pathogenicity islands) are a family of mobile genetic elements resident in the genome of some strains of Staphylococcus aureus. Much like bacteriophages, SaPIs can be transferred to uninfected cells and integrate into the host chromosome.Yersinia enterocolitica: Yersinia enterocolitica is a Gram-negative bacillus-shaped bacterium, belonging to the family Enterobacteriaceae. Y.Cutaneous group B streptococcal infection: Cutaneous group B streptococcal infection may result in orbital cellulitis or facial erysipelas in neonates.Pilin: Pilin refers to a class of fibrous proteins that are found in pilus structures in bacteria. Bacterial pili are used in the exchange of genetic material during bacterial conjugation, while a shorter type of appendages also made up of pilin, called fimbriae, are used as a cell adhesion mechanism.Septicemic plague: Septicemic (or septicaemic) plague is one of the three main forms of plague. It is caused by Yersinia pestis, a gram-negative species of bacterium.Bacterial capsule: The cell capsule is a very large structure of some prokaryotic cells, such as bacterial cells. It is a polysaccharide layer that lies outside the cell envelope of bacteria, and is thus deemed part of the outer envelope of a bacterial cell.Phenotype microarray: The phenotype microarray approach is a technology for high-throughput phenotyping of cells.Nif regulonHyphaComposite transposon: A composite transposon is similar in function to simple transposons and Insertion Sequence (IS) elements in that it has protein coding DNA segments flanked by inverted, repeated sequences that can be recognized by transposase enzymes. A composite transposon, however, is flanked by two separate IS elements which may or may not be exact replicas.Operon: In genetics, an operon is a functioning unit of genomic DNA containing a cluster of genes under the control of a single promoter. The genes are transcribed together into an mRNA strand and either translated together in the cytoplasm, or undergo trans-splicing to create monocistronic mRNAs that are translated separately, i.List of diseases (Y): This is a list of diseases starting with the letter "Y".Tingible body macrophage: A tingible body macrophage is a type of macrophage predominantly found in germinal centers, containing many phagocytized, apoptotic cells in various states of degradation, referred to as tingible bodies (tingible meaning stainable).Horst Ibelgaufts' COPE: Cytokines & Cells Online Pathfinder Encyclopaedia > tingible body macrophages Retrieved on June 27, 2010 Tingible body macrophages contain condensed chromatin fragments.Thermal cyclerSiderophore: Siderophores (Greek: "iron carrier") are small, high-affinity iron chelating compounds secreted by microorganisms such as bacteria, fungi and grasses.Miller, Marvin J.Bismuth sulfite agar: Bismuth sulfite agar is a type of agar media used to isolate Salmonella species. It uses glucose as a primary source of carbon.Secretion: Secretion is the process of elaborating, releasing, and oozing chemicals, or a secreted chemical substance from a cell or gland. In contrast to excretion, the substance may have a certain function, rather than being a waste product.Vibrio vulnificus: Vibrio vulnificus is a species of Gram-negative, motile, curved, rod-shaped (Bacillus), Pathogenic bacteria of the genus Vibrio. Present in marine environments such as estuaries, brackish ponds, or coastal areas, V.CryptococcosisPseudomonas infectionIntracellular parasite: Intracellular parasites are parasitic microorganisms - microparasites that are capable of growing and reproducing inside the cells of a host.Thiol-activated cytolysin: Cholesterol-binding cytolysin, previously incorrectly known as 'thiol-activated' cytolysins Bacterial Disease Mechanisms: Michael Wilson, Rod McNab, Brian Henderson (2002)" are toxins produced by a variety of Gram-positive bacteria and are characterised by their ability to lyse cholesterol-containing membranes, their reversible inactivation by oxidation and their capacity to bind to cholesterol.Vibrio campbellii: Vibrio campbellii is a Gram-negative, curved rod-shaped, marine bacterium closely related to its sister species, Vibrio harveyi. It is an emerging pathogen in aquatic organisms.Polysaccharide encapsulated bacteriaLigation-independent cloning: Ligation-independent cloning (LIC) is a form of molecular cloning that is able to be performed without the use of restriction endonucleases or DNA ligase. This allows genes that have restriction sites to be cloned without worry of chopping up the insert.BacitracinAcyl-homoserine-lactone synthase: Acyl-homoserine-lactone synthase (, acyl-homoserine lactone synthase, acyl homoserine lactone synthase, acyl-homoserinelactone synthase, acylhomoserine lactone synthase, AHL synthase, AHS, AHSL synthase, AhyI, AinS, AinS protein, autoinducer synthase, autoinducer synthesis protein rhlI, EsaI, ExpISCC1, ExpISCC3065, LasI, LasR, LuxI, LuxI protein, LuxM, N-acyl homoserine lactone synthase, RhlI, YspI, acyl-[acyl carrier protein]:S-adenosyl-L-methionine acyltranserase (lactone-forming, methylthioadenosine-releasing)) is an enzyme with system name acyl-(acyl-carrier protein):S-adenosyl-L-methionine acyltranserase (lactone-forming, methylthioadenosine-releasing). This eSystemic candidiasis: Systemic candidiasis is an infection of Candida albicans causing disseminated disease and sepsis, invariably when host defenses are compromised.Gene signature: A gene signature is a group of genes in a cell whose combined expression patternItadani H, Mizuarai S, Kotani H. Can systems biology understand pathway activation?Gamma-150 RNA motif: The gamma-150 RNA motif is a conserved RNA structure that is found in bacteria within the order Pseudomonadales. Because gamma-150 RNAs are not consistently in 5' UTRs, the gamma-150 motif is presumed to correspond to a non-coding RNA.CS-BLASTFrancisella tularensis: Francisella tularensis is a pathogenic species of Gram-negative, rod-shaped coccobacillus, an aerobe bacterium. It is non-spore forming, non-motile and the causative agent of tularemia, the pneumonic form of which is often lethal without treatment.Genetic variation: right|thumbCholesterol-dependent cytolysin: Cholesterol-dependent cytolysins (CDC) are a family of β-barrel pore-forming exotoxins that are secreted by Gram-positive bacteria. CDC are secreted as water-soluble monomers of 50-70 kDa, that once bound to the target cell, will form a circular homo-oligomeric complex containing up to 40 monomers, although it is possible that some may incorporate more monomers.European Community Reference Laboratory for Fish Diseases: The European Community Reference Laboratory for Fish DiseasesCommunity Reference Laboratory for Fish Diseases is located in Frederiksberg in Denmark at the National Veterinary Institute (a part of Technical University of Denmark).Hemolysis (microbiology): Hemolysis (or haemolysis in British English) is the breakdown of red blood cells. The ability of bacterial colonies to induce hemolysis when grown on blood agar is used to classify certain microorganisms.Resistome: The resistome is a proposed expression by Gerard D. Wright for the collection of all the antibiotic resistance genes and their precursors in both pathogenic and non-pathogenic bacteria.Bacillus anthracis: Bacillus anthracis is the etiologic agent of anthrax—a common disease of livestock and, occasionally, of humans—and the only obligate pathogen within the genus Bacillus. B.

(1/14670) Role of DnaK in in vitro and in vivo expression of virulence factors of Vibrio cholerae.

The dnaK gene of Vibrio cholerae was cloned, sequenced, and used to construct a dnaK insertion mutant which was then used to examine the role of DnaK in expression of the major virulence factors of this important human pathogen. The central regulator of several virulence genes of V. cholerae is ToxR, a transmembrane DNA binding protein. The V. cholerae dnaK mutant grown in standard laboratory medium exhibited phenotypes characteristic of cells deficient in ToxR activity. Using Northern blot analysis and toxR transcriptional fusions, we demonstrated a reduction in expression of the toxR gene in the dnaK mutant strain together with a concomitant increase in expression of a htpG-like heat shock gene that is located immediately upstream and is divergently transcribed from toxR. This may be due to increased heat shock induction in the dnaK mutant. In vivo, however, although expression from heat shock promoters in the dnaK mutant was similar to that observed in vitro, expression of both toxR and htpG was comparable to that by the parental strain. In both strains, in vivo expression of toxR was significantly higher than that observed in vitro, but no reciprocal decrease in htpG expression was observed. These results suggest that the modulation of toxR expression in vivo may be different from that observed in vitro.  (+info)

(2/14670) Alpha-toxin and gamma-toxin jointly promote Staphylococcus aureus virulence in murine septic arthritis.

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)

(3/14670) Role of antibodies against Bordetella pertussis virulence factors in adherence of Bordetella pertussis and Bordetella parapertussis to human bronchial epithelial cells.

Immunization with whole-cell pertussis vaccines (WCV) containing heat-killed Bordetella pertussis cells and with acellular vaccines containing genetically or chemically detoxified pertussis toxin (PT) in combination with filamentous hemagglutinin (FHA), pertactin (Prn), or fimbriae confers protection in humans and animals against B. pertussis infection. In an earlier study we demonstrated that FHA is involved in the adherence of these bacteria to human bronchial epithelial cells. In the present study we investigated whether mouse antibodies directed against B. pertussis FHA, PTg, Prn, and fimbriae, or against two other surface molecules, lipopolysaccharide (LPS) and the 40-kDa outer membrane porin protein (OMP), that are not involved in bacterial adherence, were able to block adherence of B. pertussis and B. parapertussis to human bronchial epithelial cells. All antibodies studied inhibited the adherence of B. pertussis to these epithelial cells and were equally effective in this respect. Only antibodies against LPS and 40-kDa OMP affected the adherence of B. parapertussis to epithelial cells. We conclude that antibodies which recognize surface structures on B. pertussis or on B. parapertussis can inhibit adherence of the bacteria to bronchial epithelial cells, irrespective whether these structures play a role in adherence of the bacteria to these cells.  (+info)

(4/14670) Role of Bordetella pertussis virulence factors in adherence to epithelial cell lines derived from the human respiratory tract.

During colonization of the respiratory tract by Bordetella pertussis, virulence factors contribute to adherence of the bacterium to the respiratory tract epithelium. In the present study, we examined the roles of the virulence factors filamentous hemagglutinin (FHA), fimbriae, pertactin (Prn), and pertussis toxin (PT) in the adherence of B. pertussis to cells of the human bronchial epithelial cell line NCI-H292 and of the laryngeal epithelial cell line HEp-2. Using B. pertussis mutant strains and purified FHA, fimbriae, Prn, and PT, we demonstrated that both fimbriae and FHA are involved in the adhesion of B. pertussis to laryngeal epithelial cells, whereas only FHA is involved in the adherence to bronchial epithelial cells. For PT and Prn, no role as adhesion factor was found. However, purified PT bound to both bronchial and laryngeal cells and as such reduced the adherence of B. pertussis to these cells. These data may imply that fimbriae play a role in infection of only the laryngeal mucosa, while FHA is the major factor in colonization of the entire respiratory tract.  (+info)

(5/14670) Virulence of a spaP mutant of Streptococcus mutans in a gnotobiotic rat model.

Streptococcus mutans, the principal etiologic agent of dental caries in humans, possesses a variety of virulence traits that enable it to establish itself in the oral cavity and initiate disease. A 185-kDa cell surface-localized protein known variously as antigen I/II, antigen B, PAc, and P1 has been postulated to be a virulence factor in S. mutans. We showed previously that P1 expression is necessary for in vitro adherence of S. mutans to salivary agglutinin-coated hydroxyapatite as well as for fluid-phase aggregation. Since adherence of the organism is a necessary first step toward colonization of the tooth surface, we sought to determine what effect deletion of the gene for P1, spaP, has on the colonization and subsequent cariogenicity of this organism in vivo. Germ-free Fischer rats fed a diet containing 5% sucrose were infected with either S. mutans NG8 or an NG8-derived spaP mutant strain, PC3370, which had been constructed by allelic exchange mutagenesis. At 1-week intervals for 6 weeks after infection, total organisms recovered from mandibles were enumerated. At week 6, caries lesions also were scored. A significantly lower number of enamel and dentinal carious lesions was observed for the mutant-infected rats, although there was no difference between parent and mutant in the number of organisms recovered from teeth through 6 weeks postinfection. Coinfection of animals with both parent and mutant strains resulted in an increasing predominance of the mutant strain being recovered over time, suggesting that P1 is not a necessary prerequisite for colonization. These data do, however, suggest a role for P1 in the virulence of S. mutans, as reflected by a decrease in the cariogenicity of bacteria lacking this surface protein.  (+info)

(6/14670) Identification of a cytolethal distending toxin gene locus and features of a virulence-associated region in Actinobacillus actinomycetemcomitans.

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)

(7/14670) Complete nucleotide sequence of the 27-kilobase virulence related locus (vrl) of Dichelobacter nodosus: evidence for extrachromosomal origin.

The vrl locus is preferentially associated with virulent isolates of the ovine footrot pathogen, Dichelobacter nodosus. The complete nucleotide sequence of this 27.1-kb region has now been determined. The data reveal that the locus has a G+C content much higher than the rest of the D. nodosus chromosome and contains 22 open reading frames (ORFs) encoding products including a putative adenine-specific methylase, two potential DEAH ATP-dependent helicases, and two products with sequence similarity to a bacteriophage resistance system. These ORFs are all in the same orientation, and most are either overlapping or separated by only a few nucleotides, suggesting that they comprise an operon and are translationally coupled. Expression vector studies have led to the identification of proteins that correspond to many of these ORFs. These data, in combination with evidence of insertion of vrl into the 3' end of an ssrA gene, are consistent with the hypothesis that the vrl locus was derived from the insertion of a bacteriophage or plasmid into the D. nodosus genome.  (+info)

(8/14670) Expression of the plague plasminogen activator in Yersinia pseudotuberculosis and Escherichia coli.

Enteropathogenic yersiniae (Yersinia pseudotuberculosis and Yersinia enterocolitica) typically cause chronic disease as opposed to the closely related Yersinia pestis, the causative agent of bubonic plague. It is established that this difference reflects, in part, carriage by Y. pestis of a unique 9.6-kb pesticin or Pst plasmid (pPCP) encoding plasminogen activator (Pla) rather than distinctions between shared approximately 70-kb low-calcium-response, or Lcr, plasmids (pCD in Y. pestis and pYV in enteropathogenic yersiniae) encoding cytotoxic Yops and anti-inflammatory V antigen. Pla is known to exist as a combination of 32.6-kDa (alpha-Pla) and slightly smaller (beta-Pla) outer membrane proteins, of which at least one promotes bacterial dissemination in vivo and degradation of Yops in vitro. We show here that only alpha-Pla accumulates in Escherichia coli LE392/pPCP1 cultivated in enriched medium and that either autolysis or extraction of this isolate with 1.0 M NaCl results in release of soluble alpha and beta forms possessing biological activity. This process also converted cell-bound alpha-Pla to beta-Pla and smaller forms in Y. pestis KIM/pPCP1 and Y. pseudotuberculosis PB1/+/pPCP1 but did not promote solubilization. Pla-mediated posttranslational hydrolysis of pulse-labeled Yops in Y. pseudotuberculosis PB1/+/pPCP1 occurred more slowly than that in Y. pestis but was otherwise similar except for accumulation of stable degradation products of YadA, a pYV-mediated fibrillar adhesin not encoded in frame by pCD. Carriage of pPCP by Y. pseudotuberculosis did not significantly influence virulence in mice.  (+info)


  • The pAA plasmid contains several virulence genes, including aggR, aap and aat, but not all EAEC carry the same complement of such genes. (


  • In many pathogenic bacteria, the expression of virulence factors is under the regulation of quorum sensing (QS). (
  • QS inhibitors (QSIs) present a promising alternative or potential synergistic treatment since they disrupt the signaling pathway used for intra- and interspecies coordination of expression of virulence factors. (
  • Is the Subject Area "Virulence factors" applicable to this article? (
  • This prevalence marks them as key microbial virulence factors in addition to a bacterium's ability to produce toxins and resist the immune defenses of the host. (


  • The majority of bacterial pathogens exploit specific adhesion to host cells as their main virulence factor . (


  • We searched PubMed for studies of trends in HIV-1 prognostic markers of disease progression and supplemented findings with publications referenced in epidemiological or virulence studies. (