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.Host-Pathogen Interactions: The interactions between a host and a pathogen, usually resulting in disease.Immunity, Innate: The capacity of a normal organism to remain unaffected by microorganisms and their toxins. It results from the presence of naturally occurring ANTI-INFECTIVE AGENTS, constitutional factors such as BODY TEMPERATURE and immediate acting immune cells such as NATURAL KILLER CELLS.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.Gene Expression Regulation, Bacterial: Any of the processes by which cytoplasmic or intercellular factors influence the differential control of gene action in bacteria.Plant Diseases: Diseases of plants.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.Antimicrobial Cationic Peptides: Small cationic peptides that are an important component, in most species, of early innate and induced defenses against invading microbes. In animals they are found on mucosal surfaces, within phagocytic granules, and on the surface of the body. They are also found in insects and plants. Among others, this group includes the DEFENSINS, protegrins, tachyplesins, and thionins. They displace DIVALENT CATIONS from phosphate groups of MEMBRANE LIPIDS leading to disruption of the membrane.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.)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.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.Genes, Bacterial: The functional hereditary units of BACTERIA.Phagocytosis: The engulfing and degradation of microorganisms; other cells that are dead, dying, or pathogenic; and foreign particles by phagocytic cells (PHAGOCYTES).Mice, Inbred BALB CMice, Inbred C57BLHost Specificity: The properties of a pathogen that makes it capable of infecting one or more specific hosts. The pathogen can include PARASITES as well as VIRUSES; BACTERIA; FUNGI; or PLANTS.Neutrophils: Granular leukocytes having a nucleus with three to five lobes connected by slender threads of chromatin, and cytoplasm containing fine inconspicuous granules and stainable by neutral dyes.Escherichia 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.Base Sequence: The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.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.Escherichia coli Infections: Infections with bacteria of the species ESCHERICHIA COLI.Cell Line: Established cell cultures that have the potential to propagate indefinitely.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.Lung: Either of the pair of organs occupying the cavity of the thorax that effect the aeration of the blood.Phylogeny: The relationships of groups of organisms as reflected by their genetic makeup.Defensins: Family of antimicrobial peptides that have been identified in humans, animals, and plants. They are thought to play a role in host defenses against infections, inflammation, wound repair, and acquired immunity.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.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.DNA, Bacterial: Deoxyribonucleic acid that makes up the genetic material of bacteria.Salmonella typhimurium: A serotype of Salmonella enterica that is a frequent agent of Salmonella gastroenteritis in humans. It also causes PARATYPHOID FEVER.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.Signal Transduction: 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.Sequence Analysis, DNA: A multistage process that includes cloning, physical mapping, subcloning, determination of the DNA SEQUENCE, and information analysis.Candida albicans: A unicellular budding fungus which is the principal pathogenic species causing CANDIDIASIS (moniliasis).Mice, Knockout: Strains of mice in which certain GENES of their GENOMES have been disrupted, or "knocked-out". To produce knockouts, using RECOMBINANT DNA technology, the normal DNA sequence of the gene being studied is altered to prevent synthesis of a normal gene product. Cloned cells in which this DNA alteration is successful are then injected into mouse EMBRYOS to produce chimeric mice. The chimeric mice are then bred to yield a strain in which all the cells of the mouse contain the disrupted gene. Knockout mice are used as EXPERIMENTAL ANIMAL MODELS for diseases (DISEASE MODELS, ANIMAL) and to clarify the functions of the genes.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.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.Cytokines: Non-antibody proteins secreted by inflammatory leukocytes and some non-leukocytic cells, that act as intercellular mediators. They differ from classical hormones in that they are produced by a number of tissue or cell types rather than by specialized glands. They generally act locally in a paracrine or autocrine rather than endocrine manner.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.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.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.Cells, Cultured: 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.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.Bacterial Outer Membrane Proteins: Proteins isolated from the outer membrane of Gram-negative bacteria.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.Yersinia pestis: The etiologic agent of PLAGUE in man, rats, ground squirrels, and other rodents.Microbial Viability: Ability of a microbe to survive under given conditions. This can also be related to a colony's ability to replicate.Salicylic Acid: A compound obtained from the bark of the white willow and wintergreen leaves. It has bacteriostatic, fungicidal, and keratolytic actions.beta-Defensins: DEFENSINS found mainly in epithelial cells.Cryptococcus neoformans: A species of the fungus CRYPTOCOCCUS. Its teleomorph is Filobasidiella neoformans.Antigens, Bacterial: Substances elaborated by bacteria that have antigenic activity.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.Phenotype: The outward appearance of the individual. It is the product of interactions between genes, and between the GENOTYPE and the environment.Oxylipins: Eighteen-carbon cyclopentyl polyunsaturated fatty acids derived from ALPHA-LINOLENIC ACID via an oxidative pathway analogous to the EICOSANOIDS in animals. Biosynthesis is inhibited by SALICYLATES. A key member, jasmonic acid of PLANTS, plays a similar role to ARACHIDONIC ACID in animals.Lipopolysaccharides: 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)Pseudomonas Infections: Infections with bacteria of the genus PSEUDOMONAS.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.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.Plant Leaves: Expanded structures, usually green, of vascular plants, characteristically consisting of a bladelike expansion attached to a stem, and functioning as the principal organ of photosynthesis and transpiration. (American Heritage Dictionary, 2d ed)Cyclopentanes: A group of alicyclic hydrocarbons with the general formula R-C5H9.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.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.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".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 Infections, Animal: Infections in animals with bacteria of the genus SALMONELLA.Listeriosis: Infections with bacteria of the genus LISTERIA.Macrophages, Alveolar: Round, granular, mononuclear phagocytes found in the alveoli of the lungs. They ingest small inhaled particles resulting in degradation and presentation of the antigen to immunocompetent cells.Phagocytes: Cells that can carry out the process of PHAGOCYTOSIS.Toll-Like Receptors: A family of pattern recognition receptors characterized by an extracellular leucine-rich domain and a cytoplasmic domain that share homology with the INTERLEUKIN 1 RECEPTOR and the DROSOPHILA toll protein. Following pathogen recognition, toll-like receptors recruit and activate a variety of SIGNAL TRANSDUCING ADAPTOR PROTEINS.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.Defense Mechanisms: Unconscious process used by an individual or a group of individuals in order to cope with impulses, feelings or ideas which are not acceptable at their conscious level; various types include reaction formation, projection and self reversal.Immune Evasion: Methods used by pathogenic organisms to evade a host's immune system.Bacterial Infections: Infections by bacteria, general or unspecified.Pneumonia, Bacterial: Inflammation of the lung parenchyma that is caused by bacterial infections.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)Streptococcal Infections: Infections with bacteria of the genus STREPTOCOCCUS.Yersinia enterocolitica: A species of the genus YERSINIA, isolated from both man and animal. It is a frequent cause of bacterial gastroenteritis in children.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.Escherichia coli Proteins: Proteins obtained from ESCHERICHIA COLI.Spleen: An encapsulated lymphatic organ through which venous blood filters.Opsonin Proteins: Proteins that bind to particles and cells to increase susceptibility to PHAGOCYTOSIS, especially ANTIBODIES bound to EPITOPES that attach to FC RECEPTORS. COMPLEMENT C3B may also participate.Immunity: Nonsusceptibility to the invasive or pathogenic effects of foreign microorganisms or to the toxic effect of antigenic substances.Cathelicidins: Antimicrobial cationic peptides with a highly conserved amino terminal cathelin-like domain and a more variable carboxy terminal domain. They are initially synthesized as preproproteins and then cleaved. They are expressed in many tissues of humans and localized to EPITHELIAL CELLS. They kill nonviral pathogens by forming pores in membranes.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.Aspergillus fumigatus: A species of imperfect fungi from which the antibiotic fumigatin is obtained. Its spores may cause respiratory infection in birds and mammals.Virus 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.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.Cryptococcosis: Infection with a fungus of the species CRYPTOCOCCUS NEOFORMANS.Fungal Proteins: Proteins found in any species of fungus.Anti-Bacterial Agents: Substances that reduce the growth or reproduction of BACTERIA.Lycopersicon esculentum: A plant species of the family SOLANACEAE, native of South America, widely cultivated for their edible, fleshy, usually red fruit.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.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.Disease Susceptibility: A constitution or condition of the body which makes the tissues react in special ways to certain extrinsic stimuli and thus tends to make the individual more than usually susceptible to certain diseases.Hyphae: Microscopic threadlike filaments in FUNGI that are filled with a layer of protoplasm. Collectively, the hyphae make up the MYCELIUM.Bacteria: 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.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.Staphylococcal Infections: Infections with bacteria of the genus STAPHYLOCOCCUS.Interferon-gamma: The major interferon produced by mitogenically or antigenically stimulated LYMPHOCYTES. It is structurally different from TYPE I INTERFERON and its major activity is immunoregulation. It has been implicated in the expression of CLASS II HISTOCOMPATIBILITY ANTIGENS in cells that do not normally produce them, leading to AUTOIMMUNE DISEASES.Gene Expression Regulation, Plant: Any of the processes by which nuclear, cytoplasmic, or intercellular factors influence the differential control of gene action in plants.Shigella flexneri: A bacterium which is one of the etiologic agents of bacillary dysentery (DYSENTERY, BACILLARY) and sometimes of infantile gastroenteritis.Disease Resistance: The capacity of an organism to defend itself against pathological processes or the agents of those processes. This most often involves innate immunity whereby the organism responds to pathogens in a generic way. The term disease resistance is used most frequently when referring to plants.Inflammation: A pathological process characterized by injury or destruction of tissues caused by a variety of cytologic and chemical reactions. It is usually manifested by typical signs of pain, heat, redness, swelling, and loss of function.Viral Proteins: Proteins found in any species of virus.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.Parasites: Invertebrate organisms that live on or in another organism (the host), and benefit at the expense of the other. Traditionally excluded from definition of parasites are pathogenic BACTERIA; FUNGI; VIRUSES; and PLANTS; though they may live parasitically.Protein Binding: 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.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).Tobacco: A plant genus of the family SOLANACEAE. Members contain NICOTINE and other biologically active chemicals; its dried leaves are used for SMOKING.Plant Immunity: The inherent or induced capacity of plants to withstand or ward off biological attack by pathogens.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.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.Bacterial Load: Measurable quantity of bacteria in an object, organism, or organism compartment.Models, Biological: 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.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.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.Reverse Transcriptase Polymerase Chain Reaction: A variation of the PCR technique in which cDNA is made from RNA via reverse transcription. The resultant cDNA is then amplified using standard PCR protocols.Symbiosis: The relationship between two different species of organisms that are interdependent; each gains benefits from the other or a relationship between different species where both of the organisms in question benefit from the presence of the other.Yersinia Infections: Infections with bacteria of the genus YERSINIA.Biological Evolution: The process of cumulative change over successive generations through which organisms acquire their distinguishing morphological and physiological characteristics.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.Pulmonary Surfactant-Associated Protein D: An abundant pulmonary surfactant-associated protein that binds to a variety of lung pathogens and enhances their opsinization and killing by phagocytic cells. Surfactant protein D contains a N-terminal collagen-like domain and a C-terminal lectin domain that are characteristic of members of the collectin family of proteins.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.Vibrio cholerae: The etiologic agent of CHOLERA.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.Genetic Variation: Genotypic differences observed among individuals in a population.Gene Expression Regulation: Any of the processes by which nuclear, cytoplasmic, or intercellular factors influence the differential control (induction or repression) of gene action at the level of transcription or translation.Plants: Multicellular, eukaryotic life forms of kingdom Plantae (sensu lato), comprising the VIRIDIPLANTAE; RHODOPHYTA; and GLAUCOPHYTA; all of which acquired chloroplasts by direct endosymbiosis of CYANOBACTERIA. They are characterized by a mainly photosynthetic mode of nutrition; essentially unlimited growth at localized regions of cell divisions (MERISTEMS); cellulose within cells providing rigidity; the absence of organs of locomotion; absence of nervous and sensory systems; and an alternation of haploid and diploid generations.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.Arabidopsis: A plant genus of the family BRASSICACEAE that contains ARABIDOPSIS PROTEINS and MADS DOMAIN PROTEINS. The species A. thaliana is used for experiments in classical plant genetics as well as molecular genetic studies in plant physiology, biochemistry, and development.Yersinia pseudotuberculosis: A human and animal pathogen causing mesenteric lymphadenitis, diarrhea, and bacteremia.Time Factors: Elements of limited time intervals, contributing to particular results or situations.Toll-Like Receptor 2: A pattern recognition receptor that forms heterodimers with other TOLL-LIKE RECEPTORS. It interacts with multiple ligands including PEPTIDOGLYCAN, bacterial LIPOPROTEINS, lipoarabinomannan, and a variety of PORINS.Plant Proteins: Proteins found in plants (flowers, herbs, shrubs, trees, etc.). The concept does not include proteins found in vegetables for which VEGETABLE PROTEINS is available.Hydrogen Peroxide: A strong oxidizing agent used in aqueous solution as a ripening agent, bleach, and topical anti-infective. It is relatively unstable and solutions deteriorate over time unless stabilized by the addition of acetanilide or similar organic materials.RNA, Messenger: RNA sequences that serve as templates for protein synthesis. Bacterial mRNAs are generally primary transcripts in that they do not require post-transcriptional processing. Eukaryotic mRNA is synthesized in the nucleus and must be exported to the cytoplasm for translation. Most eukaryotic mRNAs have a sequence of polyadenylic acid at the 3' end, referred to as the poly(A) tail. The function of this tail is not known for certain, but it may play a role in the export of mature mRNA from the nucleus as well as in helping stabilize some mRNA molecules by retarding their degradation in the cytoplasm.Fimbriae Proteins: Proteins that are structural components of bacterial fimbriae (FIMBRIAE, BACTERIAL) or sex pili (PILI, SEX).Serotyping: Process of determining and distinguishing species of bacteria or viruses based on antigens they share.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.Tumor Necrosis Factor-alpha: Serum glycoprotein produced by activated MACROPHAGES and other mammalian MONONUCLEAR LEUKOCYTES. It has necrotizing activity against tumor cell lines and increases ability to reject tumor transplants. Also known as TNF-alpha, it is only 30% homologous to TNF-beta (LYMPHOTOXIN), but they share TNF RECEPTORS.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.Mice, Inbred C3HTranscription Factors: Endogenous substances, usually proteins, which are effective in the initiation, stimulation, or termination of the genetic transcription process.Virulence Factors: 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)Immunity, Cellular: Manifestations of the immune response which are mediated by antigen-sensitized T-lymphocytes via lymphokines or direct cytotoxicity. This takes place in the absence of circulating antibody or where antibody plays a subordinate role.Pulmonary Surfactant-Associated Protein A: An abundant pulmonary surfactant-associated protein that binds to a variety of lung pathogens, resulting in their opsinization. It also stimulates MACROPHAGES to undergo PHAGOCYTOSIS of microorganisms. Surfactant protein A contains a N-terminal collagen-like domain and a C-terminal lectin domain that are characteristic of members of the collectin family of proteins.Genotype: The genetic constitution of the individual, comprising the ALLELES present at each GENETIC LOCUS.Receptors, Pattern Recognition: A large family of cell surface receptors that bind conserved molecular structures (PAMPS) present in pathogens. They play important roles in host defense by mediating cellular responses to pathogens.Oxidative Stress: A disturbance in the prooxidant-antioxidant balance in favor of the former, leading to potential damage. Indicators of oxidative stress include damaged DNA bases, protein oxidation products, and lipid peroxidation products (Sies, Oxidative Stress, 1991, pxv-xvi).Francisella tularensis: The etiologic agent of TULAREMIA in man and other warm-blooded animals.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.Polysaccharides, Bacterial: Polysaccharides found in bacteria and in capsules thereof.Fungi: A kingdom of eukaryotic, heterotrophic organisms that live parasitically as saprobes, including MUSHROOMS; YEASTS; smuts, molds, etc. They reproduce either sexually or asexually, and have life cycles that range from simple to complex. Filamentous fungi, commonly known as molds, refer to those that grow as multicellular colonies.Recombinant Proteins: Proteins prepared by recombinant DNA technology.Citrobacter rodentium: A species of gram-negative bacteria in the genus CITROBACTER, family ENTEROBACTERIACEAE. As an important pathogen of laboratory mice, it serves as a model for investigating epithelial hyperproliferation and tumor promotion. It was previously considered a strain of CITROBACTER FREUNDII.Sepsis: Systemic inflammatory response syndrome with a proven or suspected infectious etiology. When sepsis is associated with organ dysfunction distant from the site of infection, it is called severe sepsis. When sepsis is accompanied by HYPOTENSION despite adequate fluid infusion, it is called SEPTIC SHOCK.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.Carrier Proteins: Transport proteins that carry specific substances in the blood or across cell membranes.Protein Structure, Tertiary: 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.Pneumonia, Pneumococcal: A febrile disease caused by STREPTOCOCCUS PNEUMONIAE.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.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)Evolution, Molecular: The process of cumulative change at the level of DNA; RNA; and PROTEINS, over successive generations.Membrane Proteins: 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.Klebsiella pneumoniae: Gram-negative, non-motile, capsulated, gas-producing rods found widely in nature and associated with urinary and respiratory infections in humans.Macrophages, Peritoneal: Mononuclear phagocytes derived from bone marrow precursors but resident in the peritoneum.alpha-Defensins: DEFENSINS found in azurophilic granules of neutrophils and in the secretory granules of intestinal PANETH CELLS.Streptolysins: Exotoxins produced by certain strains of streptococci, particularly those of group A (STREPTOCOCCUS PYOGENES), that cause HEMOLYSIS.Yersinia pseudotuberculosis Infections: Infections with bacteria of the species YERSINIA PSEUDOTUBERCULOSIS.Klebsiella Infections: Infections with bacteria of the genus KLEBSIELLA.Larva: Wormlike or grublike stage, following the egg in the life cycle of insects, worms, and other metamorphosing animals.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.Anti-Infective Agents: Substances that prevent infectious agents or organisms from spreading or kill infectious agents in order to prevent the spread of infection.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.Respiratory Mucosa: The mucous membrane lining the RESPIRATORY TRACT, including the NASAL CAVITY; the LARYNX; the TRACHEA; and the BRONCHI tree. The respiratory mucosa consists of various types of epithelial cells ranging from ciliated columnar to simple squamous, mucous GOBLET CELLS, and glands containing both mucous and serous cells.Gene Expression Regulation, Fungal: Any of the processes by which nuclear, cytoplasmic, or intercellular factors influence the differential control of gene action in fungi.Phagosomes: Membrane-bound cytoplasmic vesicles formed by invagination of phagocytized material. They fuse with lysosomes to form phagolysosomes in which the hydrolytic enzymes of the lysosome digest the phagocytized material.Gene Expression: The phenotypic manifestation of a gene or genes by the processes of GENETIC TRANSCRIPTION and GENETIC TRANSLATION.Monocytes: Large, phagocytic mononuclear leukocytes produced in the vertebrate BONE MARROW and released into the BLOOD; contain a large, oval or somewhat indented nucleus surrounded by voluminous cytoplasm and numerous organelles.Bacillus anthracis: A species of bacteria that causes ANTHRAX in humans and animals.Reactive Oxygen Species: Molecules or ions formed by the incomplete one-electron reduction of oxygen. These reactive oxygen intermediates include SINGLET OXYGEN; SUPEROXIDES; PEROXIDES; HYDROXYL RADICAL; and HYPOCHLOROUS ACID. They contribute to the microbicidal activity of PHAGOCYTES, regulation of signal transduction and gene expression, and the oxidative damage to NUCLEIC ACIDS; PROTEINS; and LIPIDS.Chemokines: Class of pro-inflammatory cytokines that have the ability to attract and activate leukocytes. They can be divided into at least three structural branches: C; (CHEMOKINES, C); CC; (CHEMOKINES, CC); and CXC; (CHEMOKINES, CXC); according to variations in a shared cysteine motif.Herbivory: The act of feeding on plants by animals.Salmonella Infections: Infections with bacteria of the genus SALMONELLA.Xanthomonas: A genus in the family XANTHOMONADACEAE whose cells produce a yellow pigment (Gr. xanthos - yellow). It is pathogenic to plants.Membrane Glycoproteins: Glycoproteins found on the membrane or surface of cells.Yersinia: A genus of gram-negative, facultatively anaerobic rod- to coccobacillus-shaped bacteria that occurs in a broad spectrum of habitats.Gram-Negative Bacterial Infections: Infections caused by bacteria that show up as pink (negative) when treated by the gram-staining method.Neutrophil Infiltration: The diffusion or accumulation of neutrophils in tissues or cells in response to a wide variety of substances released at the sites of inflammatory reactions.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.Wasps: Any of numerous winged hymenopterous insects of social as well as solitary habits and having formidable stings.Plants, Genetically Modified: PLANTS, or their progeny, whose GENOME has been altered by GENETIC ENGINEERING.Antibodies, Bacterial: Immunoglobulins produced in a response to BACTERIAL ANTIGENS.Oomycetes: Eukaryotes in the group STRAMENOPILES, formerly considered FUNGI, whose exact taxonomic level is unsettled. Many consider Oomycetes (Oomycota) a phylum in the kingdom Stramenopila, or alternatively, as Pseudofungi in the phylum Heterokonta of the kingdom Chromista. They are morphologically similar to fungi but have no close phylogenetic relationship to them. Oomycetes are found in both fresh and salt water as well as in terrestrial environments. (Alexopoulos et al., Introductory Mycology, 4th ed, pp683-4). They produce flagellated, actively motile spores (zoospores) that are pathogenic to many crop plants and FISHES.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.Hemocytes: Any blood or formed element especially in invertebrates.Hemolysis: The destruction of ERYTHROCYTES by many different causal agents such as antibodies, bacteria, chemicals, temperature, and changes in tonicity.Mutagenesis: Process of generating a genetic MUTATION. It may occur spontaneously or be induced by MUTAGENS.
  • Therefore, strategies to combat certain bacterial infections by targeting these specific virulence factors and mobile genetic elements have been proposed. (wikipedia.org)
  • Several highly adapted clones have acquired specific virulence factors that are accountable for a variety of intestinal and extraintestinal diseases including diarrhea, acute inflammation, hemorrhagic colitis, urinary tract infections, septicemia, and neonatal meningitis ( 18 , 25 , 31 , 32 ). (asm.org)
  • 7652-7662, 2001) all the Y. enterocolitica strains used fell into two groups, which correlate with the low- and high-virulence phenotypes. (asm.org)
  • In addition, we found that high-virulence strains inject more YopP into the cytosol of eukaryotic target cells than do low-virulence strains. (asm.org)
  • Pathogenic Y. enterocolitica strains can be divided into a low-virulence group (biotypes 2 to 4) and a high-virulence group (biotype 1B) on the basis of lethality for mice. (asm.org)
  • Thus, PhcA helps R. solanacearum succeed over the course of its complex life cycle by ensuring avid attachment to plant surfaces and rapid growth early in disease, followed by high virulence and effective dispersal later in disease. (asm.org)
  • 1 of these biology have allowed research groups to identify numerous conditions: endocarditis, meningitis, arthritis, sepsis, pneu- virulence factors and to explore their roles in the progres- monia, osteomyelitis, and toxic shock ( 7 ). (cdc.gov)
  • ATEC lacks the EAF (EPEC adherence factor) plasmid encoding the bundle-forming pili (BFP) that in EPEC are responsible for localized adherence and the formation of microcolonies on host cells ( 2 , 14 ). (asm.org)
  • Here, we determined the virulence factors (germination, adherence, biofilm formation, phospholipase and proteinase production) of 16 C. auris isolates and their susceptibilities to 11 drugs belonging to different antifungal classes, including a novel orally bioavailable 1,3-β- d -glucan synthesis inhibitor (SCY-078). (asm.org)
  • Illicit dmage to host via: Cell Lysis, production of toxic substances, cellular transformation, indirect production of toxic substances, and host cell alterations (nuclear and cytoplasmic). (coursehero.com)
  • The first layer of defense is the recognition of pathogen-associated molecular patterns (PAMPs), such as flagellin Flg22 and chitosan, by multiple pattern recognition receptors (PRRs) at the cell surface. (nature.com)
  • and high-molecular-weight kininogen, also called Fitzgerald , Flaujeac , or Williams factor , or contact activation cofactor . (thefreedictionary.com)
  • How NLR receptors activate defense on perceiving pathogen molecules is poorly understood, especially in plants. (pnas.org)
  • 1 2 3 4 5 6 7 These molecules coupled with specific antibody, especially IgA, are generally recognized as key defense components of tears. (arvojournals.org)
  • A homogeneous non-toxic 39 kDa factor from the cytosol of GBS showing a homology with xenobiotic response element type transcriptional regulator protein adds another quill to the GBS protein panama, thus indicating that such protein molecules can be efficiently explored as suitable vaccine candidates. (intechopen.com)
  • In this context, katG expression represents a double-edged sword, as it is an important virulence determinant but at the same time its activity levels determine sensitivity to INH. (asm.org)