Lysogeny: The phenomenon by which a temperate phage incorporates itself into the DNA of a bacterial host, establishing a kind of symbiotic relation between PROPHAGE and bacterium which results in the perpetuation of the prophage in all the descendants of the bacterium. Upon induction (VIRUS ACTIVATION) by various agents, such as ultraviolet radiation, the phage is released, which then becomes virulent and lyses the bacterium.Bacteriophages: Viruses whose hosts are bacterial cells.Attachment Sites, Microbiological: Specific loci on both the bacterial DNA (attB) and the phage DNA (attP) which delineate the sites where recombination takes place between them, as the phage DNA becomes integrated (inserted) into the BACTERIAL DNA during LYSOGENY.Virus Activation: The mechanism by which latent viruses, such as genetically transmitted tumor viruses (PROVIRUSES) or PROPHAGES of lysogenic bacteria, are induced to replicate and then released as infectious viruses. It may be effected by various endogenous and exogenous stimuli, including B-cell LIPOPOLYSACCHARIDES, glucocorticoid hormones, halogenated pyrimidines, IONIZING RADIATION, ultraviolet light, and superinfecting viruses.Siphoviridae: A family of BACTERIOPHAGES and ARCHAEAL VIRUSES which are characterized by long, non-contractile tails.Streptococcus Phages: Viruses whose host is Streptococcus.Coliphages: Viruses whose host is Escherichia coli.Bacteriophage lambda: A temperate inducible phage and type species of the genus lambda-like viruses, in the family SIPHOVIRIDAE. Its natural host is E. coli K12. Its VIRION contains linear double-stranded DNA with single-stranded 12-base 5' sticky ends. The DNA circularizes on infection.Salmonella Phages: Viruses whose host is Salmonella. A frequently encountered Salmonella phage is BACTERIOPHAGE P22.Genome, Bacterial: The genetic complement of a BACTERIA as represented in its DNA.Chromosomes, Bacterial: Structures within the nucleus of bacterial cells consisting of or containing DNA, which carry genetic information essential to the cell.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.Bacteriophage mu: A temperate coliphage, in the genus Mu-like viruses, family MYOVIRIDAE, composed of a linear, double-stranded molecule of DNA, which is able to insert itself randomly at any point on the host chromosome. It frequently causes a mutation by interrupting the continuity of the bacterial OPERON at the site of insertion.DNA, Viral: Deoxyribonucleic acid that makes up the genetic material of viruses.DNA, Bacterial: Deoxyribonucleic acid that makes up the genetic material of bacteria.Bacteriophage P2: A species of temperate bacteriophage in the genus P2-like viruses, family MYOVIRIDAE, which infects E. coli. It consists of linear double-stranded DNA with 19-base sticky ends.Bacteriolysis: Rupture of bacterial cells due to mechanical force, chemical action, or the lytic growth of BACTERIOPHAGES.Transduction, Genetic: The transfer of bacterial DNA by phages from an infected bacterium to another bacterium. This also refers to the transfer of genes into eukaryotic cells by viruses. This naturally occurring process is routinely employed as a GENE TRANSFER TECHNIQUE.Genome, Viral: The complete genetic complement contained in a DNA or RNA molecule in a virus.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.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.Myoviridae: A family of BACTERIOPHAGES and ARCHAEAL VIRUSES which are characterized by complex contractile tails.Mitomycin: An antineoplastic antibiotic produced by Streptomyces caespitosus. It is one of the bi- or tri-functional ALKYLATING AGENTS causing cross-linking of DNA and inhibition of DNA synthesis.SOS Response (Genetics): An error-prone mechanism or set of functions for repairing damaged microbial DNA. SOS functions (a concept reputedly derived from the SOS of the international distress signal) are involved in DNA repair and mutagenesis, in cell division inhibition, in recovery of normal physiological conditions after DNA repair, and possibly in cell death when DNA damage is extensive.Sequence Analysis, DNA: A multistage process that includes cloning, physical mapping, subcloning, determination of the DNA SEQUENCE, and information analysis.Shiga Toxin: A toxin produced by SHIGELLA DYSENTERIAE. It is the prototype of class of toxins that inhibit protein synthesis by blocking the interaction of ribosomal RNA; (RNA, RIBOSOMAL) with PEPTIDE ELONGATION FACTORS.Mitomycins: A group of methylazirinopyrroloindolediones obtained from certain Streptomyces strains. They are very toxic antibiotics used as ANTINEOPLASTIC AGENTS in some solid tumors. PORFIROMYCIN and MITOMYCIN are the most useful members of the group.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.Base Sequence: The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.Virus Integration: Insertion of viral DNA into host-cell DNA. This includes integration of phage DNA into bacterial DNA; (LYSOGENY); to form a PROPHAGE or integration of retroviral DNA into cellular DNA to form a PROVIRUS.Staphylococcus Phages: Viruses whose host is Staphylococcus.Viral Proteins: Proteins found in any species of virus.Genes, Viral: The functional hereditary units of VIRUSES.Bacillus subtilis: A species of gram-positive bacteria that is a common soil and water saprophyte.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.Bacillus Phages: Viruses whose host is Bacillus. Frequently encountered Bacillus phages include bacteriophage phi 29 and bacteriophage phi 105.Genes, Bacterial: The functional hereditary units of BACTERIA.Gene Order: The sequential location of genes on a chromosome.DNA Viruses: Viruses whose nucleic acid is DNA.Defective Viruses: Viruses which lack a complete genome so that they cannot completely replicate or cannot form a protein coat. Some are host-dependent defectives, meaning they can replicate only in cell systems which provide the particular genetic function which they lack. Others, called SATELLITE VIRUSES, are able to replicate only when their genetic defect is complemented by a helper virus.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.Genetics, Microbial: A subdiscipline of genetics which deals with the genetic mechanisms and processes of microorganisms.Chromosome Mapping: Any method used for determining the location of and relative distances between genes on a chromosome.Inovirus: A genus of filamentous bacteriophages of the family INOVIRIDAE. Organisms of this genus infect enterobacteria, PSEUDOMONAS; VIBRIO; and XANTHOMONAS.Bacteriophage P1: A species of temperate bacteriophage in the genus P1-like viruses, family MYOVIRIDAE, which infects E. coli. It is the largest of the COLIPHAGES and consists of double-stranded DNA, terminally redundant, and circularly permuted.Vibrio cholerae: The etiologic agent of CHOLERA.Bacterial Proteins: Proteins found in any species of bacterium.Shiga Toxin 2: A toxin produced by certain pathogenic strains of ESCHERICHIA COLI such as ESCHERICHIA COLI O157. It shares 50-60% homology with SHIGA TOXIN and SHIGA TOXIN 1.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).Vibrio cholerae O1: Strains of VIBRIO CHOLERAE containing O ANTIGENS group 1. All are CHOLERA-causing strains (serotypes). There are two biovars (biotypes): cholerae and eltor (El Tor).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).Interspersed Repetitive Sequences: Copies of transposable elements interspersed throughout the genome, some of which are still active and often referred to as "jumping genes". There are two classes of interspersed repetitive elements. Class I elements (or RETROELEMENTS - such as retrotransposons, retroviruses, LONG INTERSPERSED NUCLEOTIDE ELEMENTS and SHORT INTERSPERSED NUCLEOTIDE ELEMENTS) transpose via reverse transcription of an RNA intermediate. Class II elements (or DNA TRANSPOSABLE ELEMENTS - such as transposons, Tn elements, insertion sequence elements and mobile gene cassettes of bacterial integrons) transpose directly from one site in the DNA to another.Pseudomonas Phages: Viruses whose host is Pseudomonas. A frequently encountered Pseudomonas phage is BACTERIOPHAGE PHI 6.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".Ultraviolet Rays: That portion of the electromagnetic spectrum immediately below the visible range and extending into the x-ray frequencies. The longer wavelengths (near-UV or biotic or vital rays) are necessary for the endogenous synthesis of vitamin D and are also called antirachitic rays; the shorter, ionizing wavelengths (far-UV or abiotic or extravital rays) are viricidal, bactericidal, mutagenic, and carcinogenic and are used as disinfectants.Proviruses: Duplex DNA sequences in eukaryotic chromosomes, corresponding to the genome of a virus, that are transmitted from one cell generation to the next without causing lysis of the host. Proviruses are often associated with neoplastic cell transformation and are key features of retrovirus biology.Integrases: Recombinases that insert exogenous DNA into the host genome. Examples include proteins encoded by the POL GENE of RETROVIRIDAE and also by temperate BACTERIOPHAGES, the best known being BACTERIOPHAGE LAMBDA.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.Microscopy, Electron, Transmission: Electron microscopy in which the ELECTRONS or their reaction products that pass down through the specimen are imaged below the plane of the specimen.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.Salmonella typhimurium: A serotype of Salmonella enterica that is a frequent agent of Salmonella gastroenteritis in humans. It also causes PARATYPHOID FEVER.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.Rec A Recombinases: A family of recombinases initially identified in BACTERIA. They catalyze the ATP-driven exchange of DNA strands in GENETIC RECOMBINATION. The product of the reaction consists of a duplex and a displaced single-stranded loop, which has the shape of the letter D and is therefore called a D-loop structure.Genes: A category of nucleic acid sequences that function as units of heredity and which code for the basic instructions for the development, reproduction, and maintenance of organisms.Viral Regulatory and Accessory Proteins: A broad category of viral proteins that play indirect roles in the biological processes and activities of viruses. Included here are proteins that either regulate the expression of viral genes or are involved in modifying host cell functions. Many of the proteins in this category serve multiple functions.Lactococcus lactis: A non-pathogenic species of LACTOCOCCUS found in DAIRY PRODUCTS and responsible for the souring of MILK and the production of LACTIC ACID.Corynebacterium diphtheriae: A species of gram-positive, asporogenous bacteria in which three cultural types are recognized. These types (gravis, intermedius, and mitis) were originally given in accordance with the clinical severity of the cases from which the different strains were most frequently isolated. This species is the causative agent of DIPHTHERIA.Roseobacter: A genus of obligately aerobic marine phototrophic and chemoorganotrophic bacteria, in the family RHODOBACTERACEAE.Escherichia coli Proteins: Proteins obtained from ESCHERICHIA COLI.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.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)Phylogeny: The relationships of groups of organisms as reflected by their genetic makeup.N-Acetylmuramoyl-L-alanine Amidase: An autolytic enzyme bound to the surface of bacterial cell walls. It catalyzes the hydrolysis of the link between N-acetylmuramoyl residues and L-amino acid residues in certain cell wall glycopeptides, particularly peptidoglycan. EC 3.5.1.28.Tectiviridae: A family of lipid-containing bacteriophages with double capsids which infect both gram-negative and gram-positive bacteria. It has one genus, Tectivirus.Gene Expression Regulation, Bacterial: Any of the processes by which cytoplasmic or intercellular factors influence the differential control of gene action in bacteria.Escherichia coli K12: A species of gram-negative, rod-shaped bacteria belonging to the K serogroup of ESCHERICHIA COLI. It lives as a harmless inhabitant of the human LARGE INTESTINE and is widely used in medical and GENETIC RESEARCH.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.Transformation, Genetic: Change brought about to an organisms genetic composition by unidirectional transfer (TRANSFECTION; TRANSDUCTION, GENETIC; CONJUGATION, GENETIC, etc.) and incorporation of foreign DNA into prokaryotic or eukaryotic cells by recombination of part or all of that DNA into the cell's genome.Repressor Proteins: Proteins which maintain the transcriptional quiescence of specific GENES or OPERONS. Classical repressor proteins are DNA-binding proteins that are normally bound to the OPERATOR REGION of an operon, or the ENHANCER SEQUENCES of a gene until a signal occurs that causes their release.Klebsiella oxytoca: A species of gram-negative bacteria causing URINARY TRACT INFECTIONS and SEPTICEMIA.Extrachromosomal Inheritance: Vertical transmission of hereditary characters by DNA from cytoplasmic organelles such as MITOCHONDRIA; CHLOROPLASTS; and PLASTIDS, or from PLASMIDS or viral episomal DNA.DNA Replication: The process by which a DNA molecule is duplicated.Radiation Effects: The effects of ionizing and nonionizing radiation upon living organisms, organs and tissues, and their constituents, and upon physiologic processes. It includes the effect of irradiation on food, drugs, and chemicals.Integration Host Factors: Bacterial proteins that are used by BACTERIOPHAGES to incorporate their DNA into the DNA of the "host" bacteria. They are DNA-binding proteins that function in genetic recombination as well as in transcriptional and translational regulation.Cholera Toxin: An ENTEROTOXIN from VIBRIO CHOLERAE. It consists of two major protomers, the heavy (H) or A subunit and the B protomer which consists of 5 light (L) or B subunits. The catalytic A subunit is proteolytically cleaved into fragments A1 and A2. The A1 fragment is a MONO(ADP-RIBOSE) TRANSFERASE. The B protomer binds cholera toxin to intestinal epithelial cells, and facilitates the uptake of the A1 fragment. The A1 catalyzed transfer of ADP-RIBOSE to the alpha subunits of heterotrimeric G PROTEINS activates the production of CYCLIC AMP. Increased levels of cyclic AMP are thought to modulate release of fluid and electrolytes from intestinal crypt cells.F Factor: A plasmid whose presence in the cell, either extrachromosomal or integrated into the BACTERIAL CHROMOSOME, determines the "sex" of the bacterium, host chromosome mobilization, transfer via conjugation (CONJUGATION, GENETIC) of genetic material, and the formation of SEX PILI.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.Conjugation, Genetic: A parasexual process in BACTERIA; ALGAE; FUNGI; and ciliate EUKARYOTA for achieving exchange of chromosome material during fusion of two cells. In bacteria, this is a uni-directional transfer of genetic material; in protozoa it is a bi-directional exchange. In algae and fungi, it is a form of sexual reproduction, with the union of male and female gametes.Gene Expression Regulation, Viral: Any of the processes by which cytoplasmic factors influence the differential control of gene action in viruses.Salmonella paratyphi C: A serotype of SALMONELLA ENTERICA which is an agent of PARATYPHOID FEVER in Asia, Africa, and southern Europe.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.Evolution, Molecular: The process of cumulative change at the level of DNA; RNA; and PROTEINS, over successive generations.Shiga-Toxigenic Escherichia coli: Strains of ESCHERICHIA COLI with the ability to produce at least one or more of at least two antigenically distinct, usually bacteriophage-mediated cytotoxins: SHIGA TOXIN 1 and SHIGA TOXIN 2. These bacteria can cause severe disease in humans including bloody DIARRHEA and HEMOLYTIC UREMIC SYNDROME.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.Virion: The infective system of a virus, composed of the viral genome, a protein core, and a protein coat called a capsid, which may be naked or enclosed in a lipoprotein envelope called the peplos.Haemophilus influenzae: A species of HAEMOPHILUS found on the mucous membranes of humans and a variety of animals. The species is further divided into biotypes I through VIII.Viral Plaque Assay: Method for measuring viral infectivity and multiplication in CULTURED CELLS. Clear lysed areas or plaques develop as the VIRAL PARTICLES are released from the infected cells during incubation. With some VIRUSES, the cells are killed by a cytopathic effect; with others, the infected cells are not killed but can be detected by their hemadsorptive ability. Sometimes the plaque cells contain VIRAL ANTIGENS which can be measured by IMMUNOFLUORESCENCE.DNA Nucleotidyltransferases: Enzymes that catalyze the incorporation of deoxyribonucleotides into a chain of DNA. EC 2.7.7.-.Carbadox: An antibacterial agent that has been used in veterinary practice for treating swine dysentery and enteritis and for promoting growth. However, its use has been prohibited in the UK following reports of carcinogenicity and mutagenicity. (From Martindale, The Extra Pharmacopoeia, 30th ed, p125)Salmonella enterica: A subgenus of Salmonella containing several medically important serotypes. The habitat for the majority of strains is warm-blooded animals.Genomics: The systematic study of the complete DNA sequences (GENOME) of organisms.Chloramphenicol: An antibiotic first isolated from cultures of Streptomyces venequelae in 1947 but now produced synthetically. It has a relatively simple structure and was the first broad-spectrum antibiotic to be discovered. It acts by interfering with bacterial protein synthesis and is mainly bacteriostatic. (From Martindale, The Extra Pharmacopoeia, 29th ed, p106)Nucleic Acid Hybridization: Widely used technique which exploits the ability of complementary sequences in single-stranded DNAs or RNAs to pair with each other to form a double helix. Hybridization can take place between two complimentary DNA sequences, between a single-stranded DNA and a complementary RNA, or between two RNA sequences. The technique is used to detect and isolate specific sequences, measure homology, or define other characteristics of one or both strands. (Kendrew, Encyclopedia of Molecular Biology, 1994, p503)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.Operator Regions, Genetic: The regulatory elements of an OPERON to which activators or repressors bind thereby effecting the transcription of GENES in the operon.Wolbachia: A genus of bacteria comprised of a heterogenous group of gram-negative small rods and coccoid forms associated with arthropods. (From Bergey's Manual of Systematic Bacteriology, vol 1, 1984)Vinca: A plant genus of the family APOCYNACEAE. Vinca rosea has been changed to CATHARANTHUS roseus.Genetic Variation: Genotypic differences observed among individuals in a population.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.Mozambique: A republic in southern Africa, south of TANZANIA, east of ZAMBIA and ZIMBABWE, bordered on the west by the Indian Ocean. Its capital is Maputo. It was formerly called Portuguese East Africa.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.Norfloxacin: A synthetic fluoroquinolone (FLUOROQUINOLONES) with broad-spectrum antibacterial activity against most gram-negative and gram-positive bacteria. Norfloxacin inhibits bacterial DNA GYRASE.Host 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.Synteny: The presence of two or more genetic loci on the same chromosome. Extensions of this original definition refer to the similarity in content and organization between chromosomes, of different species for example.Hot Temperature: Presence of warmth or heat or a temperature notably higher than an accustomed norm.DNA Restriction Enzymes: Enzymes that are part of the restriction-modification systems. They catalyze the endonucleolytic cleavage of DNA sequences which lack the species-specific methylation pattern in the host cell's DNA. Cleavage yields random or specific double-stranded fragments with terminal 5'-phosphates. The function of restriction enzymes is to destroy any foreign DNA that invades the host cell. Most have been studied in bacterial systems, but a few have been found in eukaryotic organisms. They are also used as tools for the systematic dissection and mapping of chromosomes, in the determination of base sequences of DNAs, and have made it possible to splice and recombine genes from one organism into the genome of another. EC 3.21.1.Chloramphenicol Resistance: Nonsusceptibility of bacteria to the action of CHLORAMPHENICOL, a potent inhibitor of protein synthesis in the 50S ribosomal subunit where amino acids are added to nascent bacterial polypeptides.Sequence Homology, Nucleic Acid: The sequential correspondence of nucleotides in one nucleic acid molecule with those of another nucleic acid molecule. Sequence homology is an indication of the genetic relatedness of different organisms and gene function.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.Genes, Regulator: Genes which regulate or circumscribe the activity of other genes; specifically, genes which code for PROTEINS or RNAs which have GENE EXPRESSION REGULATION functions.Lactobacillus: A genus of gram-positive, microaerophilic, rod-shaped bacteria occurring widely in nature. Its species are also part of the many normal flora of the mouth, intestinal tract, and vagina of many mammals, including humans. Pathogenicity from this genus is rare.Mycobacteriophages: Viruses whose host is one or more Mycobacterium species. They include both temperate and virulent types.FloridaStreptococcal Infections: Infections with bacteria of the genus STREPTOCOCCUS.RNA, Bacterial: Ribonucleic acid in bacteria having regulatory and catalytic roles as well as involvement in protein synthesis.Shiga Toxins: A class of toxins that inhibit protein synthesis by blocking the interaction of ribosomal RNA; (RNA, RIBOSOMAL) with PEPTIDE ELONGATION FACTORS. They include SHIGA TOXIN which is produced by SHIGELLA DYSENTERIAE and a variety of shiga-like toxins that are produced by pathologic strains of ESCHERICHIA COLI such as ESCHERICHIA COLI O157.RNA, Transfer, Arg: A transfer RNA which is specific for carrying arginine to sites on the ribosomes in preparation for protein synthesis.Restriction Mapping: Use of restriction endonucleases to analyze and generate a physical map of genomes, genes, or other segments of DNA.Lactobacillus casei: A rod-shaped bacterium isolated from milk and cheese, dairy products and dairy environments, sour dough, cow dung, silage, and human mouth, human intestinal contents and stools, and the human vagina.Serratia: A genus of gram-negative, facultatively anaerobic, rod-shaped bacteria that occurs in the natural environment (soil, water, and plant surfaces) or as an opportunistic human pathogen.DNA, Circular: Any of the covalently closed DNA molecules found in bacteria, many viruses, mitochondria, plastids, and plasmids. Small, polydisperse circular DNA's have also been observed in a number of eukaryotic organisms and are suggested to have homology with chromosomal DNA and the capacity to be inserted into, and excised from, chromosomal DNA. It is a fragment of DNA formed by a process of looping out and deletion, containing a constant region of the mu heavy chain and the 3'-part of the mu switch region. Circular DNA is a normal product of rearrangement among gene segments encoding the variable regions of immunoglobulin light and heavy chains, as well as the T-cell receptor. (Riger et al., Glossary of Genetics, 5th ed & Segen, Dictionary of Modern Medicine, 1992)Helper Viruses: Viruses which enable defective viruses to replicate or to form a protein coat by complementing the missing gene function of the defective (satellite) virus. Helper and satellite may be of the same or different genus.Bacteriophage Typing: A technique of bacterial typing which differentiates between bacteria or strains of bacteria by their susceptibility to one or more bacteriophages.Sulfamethazine: A sulfanilamide anti-infective agent. It has a spectrum of antimicrobial action similar to other sulfonamides.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.Serotyping: Process of determining and distinguishing species of bacteria or viruses based on antigens they share.Diphtheria Toxin: An ADP-ribosylating polypeptide produced by CORYNEBACTERIUM DIPHTHERIAE that causes the signs and symptoms of DIPHTHERIA. It can be broken into two unequal domains: the smaller, catalytic A domain is the lethal moiety and contains MONO(ADP-RIBOSE) TRANSFERASES which transfers ADP RIBOSE to PEPTIDE ELONGATION FACTOR 2 thereby inhibiting protein synthesis; and the larger B domain that is needed for entry into cells.Temperature: The property of objects that determines the direction of heat flow when they are placed in direct thermal contact. The temperature is the energy of microscopic motions (vibrational and translational) of the particles of atoms.Inverted Repeat Sequences: Copies of nucleic acid sequence that are arranged in opposing orientation. They may lie adjacent to each other (tandem) or be separated by some sequence that is not part of the repeat (hyphenated). They may be true palindromic repeats, i.e. read the same backwards as forward, or complementary which reads as the base complement in the opposite orientation. Complementary inverted repeats have the potential to form hairpin loop or stem-loop structures which results in cruciform structures (such as CRUCIFORM DNA) when the complementary inverted repeats occur in double stranded regions.Transformation, Bacterial: The heritable modification of the properties of a competent bacterium by naked DNA from another source. The uptake of naked DNA is a naturally occuring phenomenon in some bacteria. It is often used as a GENE TRANSFER TECHNIQUE.R Factors: A class of plasmids that transfer antibiotic resistance from one bacterium to another by conjugation.Centrifugation, Density Gradient: Separation of particles according to density by employing a gradient of varying densities. At equilibrium each particle settles in the gradient at a point equal to its density. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Radiation Genetics: A subdiscipline of genetics that studies RADIATION EFFECTS on the components and processes of biological inheritance.Shigella: A genus of gram-negative, facultatively anaerobic, rod-shaped bacteria that ferments sugar without gas production. Its organisms are intestinal pathogens of man and other primates and cause bacillary dysentery (DYSENTERY, BACILLARY).Listeria: A genus of bacteria which may be found in the feces of animals and man, on vegetation, and in silage. Its species are parasitic on cold-blooded and warm-blooded animals, including man.Lactococcus: A genus of gram-positive, coccoid bacteria mainly isolated from milk and milk products. These bacteria are also found in plants and nonsterile frozen and dry foods. Previously thought to be a member of the genus STREPTOCOCCUS (group N), it is now recognized as a separate genus.Replicon: Any DNA sequence capable of independent replication or a molecule that possesses a REPLICATION ORIGIN and which is therefore potentially capable of being replicated in a suitable cell. (Singleton & Sainsbury, Dictionary of Microbiology and Molecular Biology, 2d ed)Annonaceae: The custard-apple plant family of the order Magnoliales, subclass Magnoliidae, class Magnoliopsida. Some members provide large pulpy fruits and commercial timber. Leaves and wood are often fragrant. Leaves are simple, with smooth margins, and alternately arranged in two rows along the stems.Nalidixic Acid: A synthetic 1,8-naphthyridine antimicrobial agent with a limited bacteriocidal spectrum. It is an inhibitor of the A subunit of bacterial DNA GYRASE.Sequence Deletion: Deletion of sequences of nucleic acids from the genetic material of an individual.Promoter Regions, Genetic: DNA sequences which are recognized (directly or indirectly) and bound by a DNA-dependent RNA polymerase during the initiation of transcription. Highly conserved sequences within the promoter include the Pribnow box in bacteria and the TATA BOX in eukaryotes.Blotting, Southern: A method (first developed by E.M. Southern) for detection of DNA that has been electrophoretically separated and immobilized by blotting on nitrocellulose or other type of paper or nylon membrane followed by hybridization with labeled NUCLEIC ACID PROBES.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.NitrosoguanidinesBacterial 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.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.Shiga Toxin 1: A toxin produced by certain pathogenic strains of ESCHERICHIA COLI such as ESCHERICHIA COLI O157. It is closely related to SHIGA TOXIN produced by SHIGELLA DYSENTERIAE.Sequence Homology: The degree of similarity between sequences. Studies of AMINO ACID SEQUENCE HOMOLOGY and NUCLEIC ACID SEQUENCE HOMOLOGY provide useful information about the genetic relatedness of genes, gene products, and species.Viral Tail Proteins: Proteins found in the tail sections of DNA and RNA viruses. It is believed that these proteins play a role in directing chain folding and assembly of polypeptide chains.Electrophoresis, Gel, Pulsed-Field: Gel electrophoresis in which the direction of the electric field is changed periodically. This technique is similar to other electrophoretic methods normally used to separate double-stranded DNA molecules ranging in size up to tens of thousands of base-pairs. However, by alternating the electric field direction one is able to separate DNA molecules up to several million base-pairs in length.Genotype: The genetic constitution of the individual, comprising the ALLELES present at each GENETIC LOCUS.Phenotype: The outward appearance of the individual. It is the product of interactions between genes, and between the GENOTYPE and the environment.Corynebacterium glutamicum: A species of gram-positive, asporogenous, non-pathogenic, soil bacteria that produces GLUTAMIC ACID.Bacillus: A genus of BACILLACEAE that are spore-forming, rod-shaped cells. Most species are saprophytic soil forms with only a few species being pathogenic.Drug Resistance, Microbial: The ability of microorganisms, especially 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).Exodeoxyribonucleases: A family of enzymes that catalyze the exonucleolytic cleavage of DNA. It includes members of the class EC 3.1.11 that produce 5'-phosphomonoesters as cleavage products.Viral Structural Proteins: Viral proteins that are components of the mature assembled VIRUS PARTICLES. They may include nucleocapsid core proteins (gag proteins), enzymes packaged within the virus particle (pol proteins), and membrane components (env proteins). These do not include the proteins encoded in the VIRAL GENOME that are produced in infected cells but which are not packaged in the mature virus particle,i.e. the so called non-structural proteins (VIRAL NONSTRUCTURAL PROTEINS).Viral Interference: A phenomenon in which infection by a first virus results in resistance of cells or tissues to infection by a second, unrelated virus.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.Deoxyribonucleases: Enzymes which catalyze the hydrolases of ester bonds within DNA. EC 3.1.-.DNA Fingerprinting: A technique for identifying individuals of a species that is based on the uniqueness of their DNA sequence. Uniqueness is determined by identifying which combination of allelic variations occur in the individual at a statistically relevant number of different loci. In forensic studies, RESTRICTION FRAGMENT LENGTH POLYMORPHISM of multiple, highly polymorphic VNTR LOCI or MICROSATELLITE REPEAT loci are analyzed. The number of loci used for the profile depends on the ALLELE FREQUENCY in the population.Bacteriophage P22: A species of temperate bacteriophage in the genus P22-like viruses, family PODOVIRIDAE, that infects SALMONELLA species. The genome consists of double-stranded DNA, terminally redundant, and circularly permuted.Exodeoxyribonuclease V: An ATP-dependent exodeoxyribonuclease that cleaves in either the 5'- to 3'- or the 3'- to 5'-direction to yield 5'-phosphooligonucleotides. It is primarily found in BACTERIA.Rhodobacteraceae: A family in the order Rhodobacterales, class ALPHAPROTEOBACTERIA.Endopeptidases: A subclass of PEPTIDE HYDROLASES that catalyze the internal cleavage of PEPTIDES or PROTEINS.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.TritiumAzo CompoundsRibotyping: RESTRICTION FRAGMENT LENGTH POLYMORPHISM analysis of rRNA genes that is used for differentiating between species or strains.Escherichia coli Infections: Infections with bacteria of the species ESCHERICHIA COLI.ThymidineMutagenesis, 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.Factor For Inversion Stimulation Protein: A highly abundant DNA binding protein whose expression is strongly correlated with the growth phase of bacteria. The protein plays a role in regulating DNA topology and activation of RIBOSOMAL RNA transcription. It was originally identified as a factor required for inversion stimulation by the Hin recombinase of SALMONELLA and Gin site-specific recombinase of BACTERIOPHAGE MU.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.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.DNA Repair: The reconstruction of a continuous two-stranded DNA molecule without mismatch from a molecule which contained damaged regions. The major repair mechanisms are excision repair, in which defective regions in one strand are excised and resynthesized using the complementary base pairing information in the intact strand; photoreactivation repair, in which the lethal and mutagenic effects of ultraviolet light are eliminated; and post-replication repair, in which the primary lesions are not repaired, but the gaps in one daughter duplex are filled in by incorporation of portions of the other (undamaged) daughter duplex. Excision repair and post-replication repair are sometimes referred to as "dark repair" because they do not require light.DNA, Intergenic: Any of the DNA in between gene-coding DNA, including untranslated regions, 5' and 3' flanking regions, INTRONS, non-functional pseudogenes, and non-functional repetitive sequences. This DNA may or may not encode regulatory functions.Suppression, Genetic: Mutation process that restores the wild-type PHENOTYPE in an organism possessing a mutationally altered GENOTYPE. The second "suppressor" mutation may be on a different gene, on the same gene but located at a distance from the site of the primary mutation, or in extrachromosomal genes (EXTRACHROMOSOMAL INHERITANCE).Host-Pathogen Interactions: The interactions between a host and a pathogen, usually resulting in disease.ThymineKanamycin: Antibiotic complex produced by Streptomyces kanamyceticus from Japanese soil. Comprises 3 components: kanamycin A, the major component, and kanamycins B and C, the minor components.RNA, Transfer, Amino Acid-Specific: A group of transfer RNAs which are specific for carrying each one of the 20 amino acids to the ribosome in preparation for protein synthesis.Deoxyribonucleases, Type II Site-Specific: Enzyme systems containing a single subunit and requiring only magnesium for endonucleolytic activity. The corresponding modification methylases are separate enzymes. The systems recognize specific short DNA sequences and cleave either within, or at a short specific distance from, the recognition sequence to give specific double-stranded fragments with terminal 5'-phosphates. Enzymes from different microorganisms with the same specificity are called isoschizomers. EC 3.1.21.4.Water Microbiology: The presence of bacteria, viruses, and fungi in water. This term is not restricted to pathogenic organisms.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).UracilArtificial Gene Fusion: The in vitro fusion of GENES by RECOMBINANT DNA techniques to analyze protein behavior or GENE EXPRESSION REGULATION, or to merge protein functions for specific medical or industrial uses.Bacterial Outer Membrane Proteins: Proteins isolated from the outer membrane of Gram-negative bacteria.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.Recombinases: A broad category of enzymes that are involved in the process of GENETIC RECOMBINATION.Site-Specific DNA-Methyltransferase (Adenine-Specific): An enzyme responsible for producing a species-characteristic methylation pattern on adenine residues in a specific short base sequence in the host cell DNA. The enzyme catalyzes the methylation of DNA adenine in the presence of S-adenosyl-L-methionine to form DNA containing 6-methylaminopurine and S-adenosyl-L-homocysteine. EC 2.1.1.72.
Inhibition of spontaneous induction of lambdoid prophages in Escherichia coli cultures: simple procedures with possible biotechnological applications. (1/408)
BACKGROUND: Infections of bacterial cultures by bacteriophages are serious problems in biotechnological laboratories. Apart from such infections, prophage induction in the host cells may also be dangerous. Escherichia coli is a commonly used host in biotechnological production, and many laboratory strains of this bacterium harbour lambdoid prophages. These prophages may be induced under certain conditions leading to phage lytic development. This is fatal for further cultivations as relatively low, though still significant, numbers of phages may be overlooked. Thus, subsequent cultures of non-lysogenic strains may be infected and destroyed by such phage. RESULTS: Here we report that slow growth of bacteria decreases deleterious effects of spontaneous lambdoid prophage induction. Moreover, replacement of glucose with glycerol in a medium stimulates lysogenic development of the phage after infection of E. coli cells. A plasmid was constructed overexpressing the phage 434 cI gene, coding for the repressor of phage promoters which are necessary for lytic development. Overproduction of the cI repressor abolished spontaneous induction of the lambda(imm434) prophage. CONCLUSIONS: Simple procedures that alleviate problems with spontaneous induction of lambdoid prophage and subsequent infection of E. coli strains by these phages are described. Low bacterial growth rate, replacement of glucose with glycerol in a medium and overproduction of the cI repressor minimise the risk of prophage induction during cultivation of lysogenic bacteria and subsequent infection of other bacterial strains. (+info)Pilot study of the genetic diversity of the pneumococcal nasopharyngeal flora among children attending day care centers. (2/408)
A pilot study was conducted to determine the genetic diversity of multiple colonies of pneumococci recovered from 37 nasopharyngeal (NP) samples of children. A total of 239 pneumococcal isolates (typically, six to eight colonies per sample) were typed by pulsed-field gel electrophoresis (PFGE). In most NP samples (89%) the multiple colonies shared common PFGE types and serotypes. However, four samples were heterogeneous (samples A through D): each contained two strains with different PFGE types, antibiotypes, and serotypes. Samples A and B each contained one strain of a vaccine capsular type and another expressing a non-vaccine type (according to the currently licensed seven-valent conjugate vaccine). In samples B and C the penicillin MIC for one strain was elevated and the other strain was susceptible. In each of the heterogeneous samples, one of the strains was a representative of an internationally disseminated clone. Samples A, C, and D contained strains which carried prophages that were inducible by mitomycin C and that could be visualized by electron microscopy. The comC gene allele (which encodes the competence-stimulating peptide) was the same in both strains found in each of samples A, B, and D. Carriage of multiple pneumococci with distinct properties should favor genetic exchange and provide a dynamic population structure for pneumococci in their ecological reservoir. Quantitative resolution of majority and minority components of the pneumococcal NP flora will be of importance for evaluation of the impact of intervention strategies such as vaccination or introduction of new antimicrobial agents. (+info)Phenotypes of lexA mutations in Salmonella enterica: evidence for a lethal lexA null phenotype due to the Fels-2 prophage. (3/408)
The LexA protein of Escherichia coli represses the damage-inducible SOS regulon, which includes genes for repair of DNA. Surprisingly, lexA null mutations in Salmonella enterica are lethal even with a sulA mutation, which corrects lexA lethality in E. coli. Nine suppressors of lethality isolated in a sulA mutant of S. enterica had lost the Fels-2 prophage, and seven of these (which grew better) had also lost the Gifsy-1 and Gifsy-2 prophages. All three phage genomes included a homologue of the tum gene of coliphage 186, which encodes a LexA-repressed cI antirepressor. The tum homologue of Fels-2 was responsible for lexA lethality and had a LexA-repressed promoter. This basis of lexA lethality was unexpected because the four prophages of S. enterica LT2 are not strongly UV inducible and do not sensitize strains to UV killing. In S. enterica, lexA(Ind(-)) mutants have the same phenotypes as their E. coli counterparts. Although lexA null mutants express their error-prone DinB polymerase constitutively, they are not mutators in either S. enterica or E. coli. (+info)The Shiga-toxin VT2-encoding bacteriophage varphi297 integrates at a distinct position in the Escherichia coli genome. (4/408)
The plaque-forming VT2-encoding lambdoid bacteriophage varphi297 was isolated from a Belgian clinical Escherichia coli O157:H7 isolate. PCR walking, starting from the int gene of phage varphi297, demonstrated that the varphi297 prophage integrated in the yecE gene of a lysogenic E. coli K12 strain. This integration site, in E. coli K12 and in the original clinical O157:H7 isolate, was confirmed by PCR using primers flanking this site. The excisionase protein of phage varphi297 is identical to the excisionase of VT1-encoding phage VT1-Sakai, while the integrases, which are 82% identical, show significant sequence divergence in the central and C-terminal region. This can explain the different integration sites of both prophages. The activity of the integrase was proven by its ability to mediate the integration of a suicide plasmid, carrying the attachment site of varphi297, at the appropriate position in the E. coli chromosome. (+info)Transcription analysis of Streptococcus thermophilus phages in the lysogenic state. (5/408)
The transcription of prophage genes was studied in two lysogenic Streptococcus thermophilus cells by Northern blot and primer-extension experiments. In the lysogen containing the cos-site phage Sfi21 only two gene regions of the prophage were transcribed. Within the lysogeny module an 1.6-kb-long mRNA started at the promoter of the phage repressor gene and covered also the next two genes, including a superinfection exclusion (sie) gene. A second, quantitatively more prominent 1-kb-long transcript was initiated at the promoter of the sie gene. Another prophage transcript of 1.6-kb length covered a group of genes without database matches that were located between the lysin gene and the right attachment site. The rest of the prophage genome was transcriptionally silent. A very similar transcription pattern was observed for a S. thermophilus lysogen containing the pac-site phage O1205 as a prophage. Prophages from pathogenic streptococci encode virulence genes downstream of the lysin gene. We speculate that temperate phages from lactic streptococci also encode nonessential phage genes ("lysogenic conversion genes") in this region that increase the ecological fitness of the lysogen to further their own evolutionary success. A comparative genome analysis revealed that many temperate phages from low GC content Gram-positive bacteria encode a variable number of genes in that region and none was linked to known phage-related function. Prophages from pathogenic streptococci encode toxin genes in this region. In accordance with theoretical predictions on prophage-host genome interactions a prophage remnant was detected in S. thermophilus that had lost most of the prophage DNA while transcribed prophage genes were spared from the deletion process. (+info)Genome analysis of an inducible prophage and prophage remnants integrated in the Streptococcus pyogenes strain SF370. (6/408)
The mitomycin C inducible prophage SF370.1 from the highly pathogenic M1 serotype Streptococcus pyogenes isolate SF370 showed a 41-kb-long genome whose genetic organization resembled that of SF11-like pac-site Siphoviridae. Its closest relative was prophage NIH1.1 from an M3 serotype S. pyogenes strain, followed by S. pneumoniae phage MM1 and Lactobacillus phage phig1e, Listeria phage A118, and Bacillus phage SPP1 in a gradient of relatedness. Sequence similarity with the previously described prophages SF370.2 and SF370.3 from the same polylysogenic SF370 strain were mainly limited to the tail fiber genes. As in these two other prophages, SF370.1 encoded likely lysogenic conversion genes between the phage lysin and the right attachment site. The genes encoded the pyrogenic exotoxin C of S. pyogenes and a protein sharing sequence similarity with both DNases and mitogenic factors. The screening of the SF370 genome revealed further prophage-like elements. A 13-kb-long phage remnant SF370.4 encoded lysogeny and DNA replication genes. A closely related prophage remnant was identified in S. pyogenes strain Manfredo at a corresponding genome position. The two prophages differed by internal indels and gene replacements. Four phage-like integrases were detected; three were still accompanied by likely repressor genes. All prophage elements were integrated into coding sequences. The phage sequences complemented the coding sequences in all cases. The DNA repair genes mutL and mutS were separated by the prophage remnant SF370.4; prophage SF370.1 and S. pneumoniae phage MM1 integrated into homologous chromosomal locations. The prophage sequences were interpreted with a hypothesis that predicts elements of cooperation and an arms race between phage and host genomes. (+info)Use of real-time quantitative PCR for the analysis of phiLC3 prophage stability in lactococci. (7/408)
Bacteriophages are a common and constant threat to proper milk fermentation. It has become evident that lysogeny is widespread in lactic acid bacteria, and in this work the temperate lactococcal bacteriophage phi LC3 was used as a model to study prophage stability in lactococci. The stability was analyzed in six phi LC3 lysogenic Lactococcus lactis subsp. cremoris host strains when they were growing at 15 and 30 degrees C. In order to perform these analyses, a real-time PCR assay was developed. The stability of the phi LC3 prophage was found to vary with the growth phase of its host L. lactis IMN-C1814, in which the induction rate increased during the exponential growth phase and reached a maximum level when the strain was entering the stationary phase. The maximum spontaneous induction frequency of the phi LC3 prophage varied between 0.32 and 9.1% (28-fold) in the six lysogenic strains. No correlation was observed between growth rates of the host cells and the spontaneous prophage induction frequencies. Furthermore, the level of extrachromosomal phage DNA after induction of the prophage varied between the strains (1.9 to 390%), and the estimated burst sizes varied up to eightfold. These results show that the host cells have a significant impact on the lytic and lysogenic life styles of temperate bacteriophages. The present study shows the power of the real-time PCR technique in the analysis of temperate phage biology and will be useful in work to reveal the impact of temperate phages and lysogenic bacteria in various ecological fields. (+info)Genesis of variants of Vibrio cholerae O1 biotype El Tor: role of the CTXphi array and its position in the genome. (8/408)
The gene encoding cholera toxin, the principal virulence factor of Vibrio cholerae, is encoded by a filamentous, lysogenic bacteriophage known as CTXphi. The genome of V. cholerae, the host for CTXphi, consists of two chromosomes, one large and one small. Here, it is shown that localization and array of CTX prophage DNA in either the large or small chromosome of V. cholerae is likely to be one of the reasons for the emergence of O1 biotype El Tor variants isolated just before and after the V. cholerae O139 cholera outbreak in 1992. Analyses of the organization of the CTX region of the genome of pre-O139 El Tor strains revealed that these strains carry two distinct CTX prophages integrated in the small chromosome in tandem: CTX(ET), the prophage having a conserved NotI site in its repeat sequence segment which seems to be specific for the El Tor strains so far examined, followed by CTX(calc)-like genome, the prophage found in recent O139 clinical isolates from Calcutta. In sharp contrast, in post-O139 El Tor strains only one copy of the CTX(ET) prophage was found to be integrated in the large chromosome. To the authors' knowledge, the presence of CTX prophage in the small chromosome of O1 El Tor strains has not been reported previously. It is also shown that the difference in the CTX copy number and the position of the bacteriophage on the genomes of pre- and post-O139 El Tor strains have an effect on cholera toxin production. While a pre-O139 strain produced maximum cholera toxin in yeast extract/peptone medium at 30 degrees C, a post-O139 El Tor strain showed maximal yield at 37 degrees C, indicating differential regulation of cholera toxin between the strains. It appears from this study that the variation in the integration site of the CTX prophage, its copy number and the presence of diverse phage genomes in V. cholerae O1 biotype El Tor may be strategically important for generating variants with subtle phenotypic modulations of virulence factor production in this longest-ruling seventh pandemic strain. (+info)GenomePhageGenesGenomesInductionStrainsPhagesBacteriophageBacillusPlasmidsLysogenyBacteriumSequencesEscherichiaRecombinationIsolatesGeneProteinsBacteriaStaphylococcusExcision of the prophagePathogenicityCharacterizationCorynebacteriumChromosomeStrainProteinChromosomesMitomycinPutative prophagesGenomicSerratia2017HolinEntericaSpeciesLytic cycleColiTemperatePathogenic
- A prophage is a bacteriophage (often shortened to "phage") genome inserted and integrated into the circular bacterial DNA chromosome or existing as an extrachromosomal plasmid. (wikipedia.org)
- Pro means ''before'', so, prophage means the stage of a virus in the form of genome inserted into host DNA before attaining its real form inside host. (wikipedia.org)
- More than 80 genome sequences of staphylococcal bacteriophages and prophages are available in the public genome databases. (asm.org)
- As little is known about the phage diversity in C. diphtheriae in India, the present study was undertaken to investigate the prophages integrated into the genome of 29 clinical isolates of C. diphtheriae using whole-genome shotgun sequencing. (nih.gov)
- Despite the essentially catalytic role of the integrase in both integrative and excisive recombination, RDFs are required to direct the reaction towards excision and to prevent re-integration of the prophage genome when entering a lytic cycle. (mdpi.com)
- Site specific recombination (SSR) constitutes a key step in lysogenic development since it is required for integration as well as for excision of the prophage genome [ 6 ]. (mdpi.com)
- This enables the prophage to be passively replicated with the host genome and ensures that a prophage is present in each of the daughter cells after division. (asm.org)
- Using whole genome sequences of 1,760 isolates of S. enterica representing 151 Salmonella serovars and 66 closely related bacteria, prophage sequences were identified from assembled contigs using PHASTER. (frontiersin.org)
- Prophage sequences were highly variable among S. enterica serovars with a median ± interquartile range (IQR) of 5 ± 3 prophage regions per genome. (frontiersin.org)
- Taken altogether, the diversity of the prophage sequences correlates with genome diversity. (frontiersin.org)
- The data obtained reveal that the horizontal transfer of mobile genetic elements (MGE), such as conjugative transposons and prophages, likely accounts for the great plasticity of the C. difficile genome ( 23 , 39 , 43 ). (asm.org)
- Since damage of the bacterial genome results in prophage induction, the reactivity of each compound with the genome may be indicated by the minimum concentration required for prophage induction and the maximum frequency of prophage induction. (aspetjournals.org)
- The highly flexible genome is genetically diverse and encodes several mobile elements, including transposons and prophages ( 18 , 43 , 47 , 48 ). (asm.org)
- Comparative genome analysis indicates that, while the Georgian strains are the nearest neighbors to the 2011 outbreak isolates sequenced to date, structural and nucleotide-level differences are evident in the Stx2 phage genomes, the mer/tet antibiotic resistance island, and in the prophage and plasmid profiles of the strains, including a previously undescribed plasmid with homology to the pMT virulence plasmid of Yersinia pestis. (nih.gov)
- In this study, we determined the effect of the prophage and its ORF14 on the virulence and competitive fitness of its carrier strain UW551 by deleting the orf14 gene only (the UW551 orf14 mutant), and nine of the prophage's 14 genes including orf14 and six out of seven structural genes (the UW551 prophage mutant), respectively, from the genome of UW551. (frontiersin.org)
- The recently published ' Ca. L. asiaticus' psy62 genome, derived from a psyllid, revealed a prophage-like region of DNA in the genome, but phage have not been associated with ' Ca. L. asiaticus' to date. (apsnet.org)
- Expression of the lysis cassette ( essD, ybcT, rzpD/rzoD ) from the defective lambdoid prophage at the 12th minute of Escherichia coli's genome (DLP12) is required in some strains for proper curli expression and biofilm formation. (microbiologyresearch.org)
- Some phage integrate their genome into the host genome upon infection (prophage), where they may potentially remain indefinitely, coevolving with the host, and providing growth factors and other benefits to the host. (umaine.edu)
- The purpose of my research is to characterize a prophage within the genome of the bacterial host Mycobacterium chelonae Bergey to determine if it is still functional and potentially impacting the fitness of the host bacterium. (umaine.edu)
- The B. anthracis genome sequence contains four putative lambdoid prophages. (biomedcentral.com)
- Prophages, like plasmids, conjugative transposons, insertion sequences, introns and other elements, make up a mobile portion of bacterial genome subject to frequent horizontal exchange that often account for large-scale genomic rearrangements and insertions and deletions in bacterial chromosomes. (biomedcentral.com)
- Prophages are phages that have integrated into the bacterial genome. (phantome.org)
- Some prophages remain active - ready to pop back out of the genome and lyse their unsuspecting hosts. (phantome.org)
- The objectives of this study were to determine the prevalence, diversity and molecular epidemiology of prophages (phage DNA integrated within the bacterial genome) among pneumococci isolated over the past 90 years. (ox.ac.uk)
- We revealed that every pneumococcal genome contained prophage DNA. (ox.ac.uk)
- Prophages typically integrated in one of five different sites within the pneumococcal genome. (ox.ac.uk)
- Abstract Prophages (viral genomes integrated within a host bacterial genome) are abundant within the bacterial world and are of interest because they often confer various phenotypic traits to their hosts, such as by encoding genes that increase pathogenicity. (ox.ac.uk)
- The majority of pathogenic bacteria, including M. tuberculosis , carry viral genomes (prophage) within the bacterial genome that are thought to contribute to virulence. (maineidea.net)
- Previous studies by Davidson's team found that nine proteins encoded in prophage DNA sequences integrated in Pseudomonas aeruginosa's genome had anti-CRISPR activity. (labcritics.com)
- Thus, a prophage is a complete genome of a phage and contains about 100 genes. (thefreedictionary.com)
- The location of a prophage is genetically controlled by its special region, which constitutes about 1/15 of the total length of the genome. (thefreedictionary.com)
- exDNA isolation was found to enrich for circular prophage elements, and qPCR characterization of the strains revealed that such prophage enrichment is detectable only in exDNA samples and would likely be missed in whole-genome DNA preparations (e.g., detection of episomal prophages did not correlate with higher prophage excision rates nor higher excised prophage copy numbers in qPCR experiments using whole-genome DNA). (umaryland.edu)
- In addition, double lysogens were found to be more sensitive to an increased induction stimulus than single lysogens, suggesting that maintenance of a stable prophage is less likely when multiple phage genome copies are present. (microbiologyresearch.org)
- The results reveal numerous differences in both genome structure and gene content among elements derived from different species as well as from strains within species, due in part to the incorporation of additional DNA, or 'morons' into the prophage genomes. (beds.ac.uk)
- Seven prophages were identified within the genome of P. aeruginosa ATCC 27853. (biomedcentral.com)
- The complete genome sequence of P. aeruginosa ATCC 27853 reveals the comprehensive genetic background of the strain, and provides genetic basis for several interesting findings about the functions of surface associated proteins, prophages, and genomic islands. (biomedcentral.com)
- Maximum-likelihood tree of 212 Salmonella Typhimurium and monophasic isolates was constructed by using 12,793 single-nucleotide polymorphisms (SNPs) outside of prophage elements, insertion sequence elements and sequence repeats identified by reference to the whole-genome sequence of Salmonella Typhimurium strain SL1344. (cdc.gov)
- The genomes of w Bol1-b and w Pip are similar in genomic organisation, sequence and gene content, but show substantial differences at some rapidly evolving regions of the genome, primarily associated with prophage and repetitive elements. (biomedcentral.com)
- Most bacterial chromosomes contain "cryptic" prophages that have lost genes required for production of phage progeny but retain genes of unknown function that may be important for regulating bacterial host physiology. (asm.org)
- If a target cell doesn't have the same prophage, upon infection by a phage the lytic pathway is immediately activated. (wikipedia.org)
- It is typical for such prophages to be integrated into the bacterial chromosome, but extrachromosomally replicating prophages have been described also, with the best characterized being the Escherichia coli phage P1 system. (asm.org)
- Here, we identify segments of phage genomes that are used for stable extrachromosomal replication in the prophage state. (asm.org)
- Phage fels- 1 and fels- 2 in supernatants were identified by primer/PCR as a putative selective force following single plaque isolations on a prophage-free strain and testing on appropriate hosts. (wiley.com)
- However, in competitions of an archived strain with S . Typhimurium ATCC 14028, phage emerged that had a DNA base sequence segment of prophage ST64B but the sequence differed from the reported homologous segment in ST64B. (wiley.com)
- The time course of phage production was similar to that observed for mitomycin C induction of wild-type prophage. (asm.org)
- Further evidence of C. difficile prophage presence comes from transmission electron microscopy (TEM) analysis of six distinct ribotypes and hybridization analysis of 37 clinical isolates, which both suggested phage carriage was common ( 8 , 11 ). (asm.org)
- Our study is the first toward a better understanding of the co-existence between a lysogenic phage and its carrier plant pathogenic bacterial strain by determining the effect of the prophage Rs551 and its repressor on the virulence and competitive fitness of its carrier strain UW551 of R. solanacearum . (frontiersin.org)
- The paradigm of prophage induction, as set by the phage Lambda model, sees the process initiated by the RecA-stimulated self-proteolysis of the phage repressor. (prolekare.cz)
- In contrast, the Gifsy-2 phage repressor, GtgR, is insensitive to GfoA and GfhA, but is inactivated by an antirepressor from the unrelated Fels-1 prophage (FsoA). (prolekare.cz)
- Since phage and chromosomal sequences near the attachment sites of most prophages are conserved, PCR can be used to assess the phage occupancy of these sites. (asmscience.org)
- Our finding that Las population dynamics derive from the prophage/phage activities may lead to a better understanding of how these bacteria evolve and adapt in different ecological niches. (escholarship.org)
- Excision of prophages could be detected by a PCR based assay for attP sites on extra-chromosomal phage circles and for attB sites on phage-excised chromosomes. (biomedcentral.com)
- All four prophages appear to be defective since, mitomycin C induced culture did not release any viable phage particle or lyse the cells or reveal any phage particle under electron microscopic examination. (biomedcentral.com)
- All four prophages can excise at low frequencies, but are apparently defective in phage production. (biomedcentral.com)
- For phage biologists, prophages have provided years of amusement. (phantome.org)
- We have developed tools that will allow you to identify prophages even if they don't have any similarity to known phage genes. (phantome.org)
- Given that nearly all pathogenic bacteria contain prophage, understanding how phage alter pathogenicity and fitness in bacterial hosts is highly relevant to preventing and treating disease. (maineidea.net)
- The proline and methionine requirements and the resistance to mitomycin C were shown to segregate together in phage PBS1-mediated transduction crosses and to be linked to thiB , which is known to be co-transducible with the PBSX prophage. (microbiologyresearch.org)
- Lysis plaques of lambda phage on E. In response to stress, the activated prophage is excised from the DNA of the host cell by one of the newly expressed gene products and enters its lytic pathway. (alitcg.com)
- The prophage of a λ-phage, for example, is localized in a chromosome of colibacillus together with the gene that controls the splitting of galactose. (thefreedictionary.com)
- Co-transcriptional DNA and RNA targeting by type III-A CRISPR-Cas systems restricts temperate phage lytic infections while allowing lysogenic infections to be tolerated under conditions where the prophage targets are transcriptionally repressed. (elsevier.com)
- Recently, we identified plasmidial and episomal prophages in S. aureus strains using an extra-chromosomal DNA (exDNA) isolation and sequencing approach, uncovering the plasmidial phage ϕBU01, which was found to encode important virulence determinants. (umaryland.edu)
- The results from these studies will lead us to understand the role of prophages in diseases caused by S. aureus, and how we can make S. aureus more susceptible to immune responses by blocking the phage contribution mechanism. (elsevier.com)
- During phage-mediated replication and host cell lysis, the toxins are released en masse from the bacterial cells, and the severity of disease is linked inexorably to toxin load. (microbiologyresearch.org)
- Prophages mediate defense against phage infection through diverse mechanisms. (nature.com)
- Members of this protein family are found in temperate phage and bacterial prophage regions. (jcvi.org)
- This description will facilitate an understanding of how foreign genes can be expressed during the process of prophage induction, and a particular example will be described. (asmscience.org)
- Foreign genes are most commonly expressed from a prophage in the lysogenic state. (asmscience.org)
- Possibly, the DNA methylase, endonuclease, or other Lrm1 genes provide a function crucial to L. rhamnosus M1 survival, resulting in the stability of the defective prophage in its lysogenic state. (environmental-expert.com)
- Prophage genes represent the majority of the accessory genes in bacteria genomes and have potential to be used as high discrimination markers in Salmonella . (frontiersin.org)
- Genes from the exo-xis region of λ and Shiga toxin-converting bacteriophages influence lysogenization and prophage induction. (nih.gov)
- We conclude that genes from the exo-xis region of lambdoid bacteriophages participate in the regulation of lysogenization and prophage maintenance. (nih.gov)
- SC2 also appeared to lack lytic cycle genes and replicated as a prophage excision plasmid, in addition to being found integrated in tandem with SC1 in the UF506 chromosome. (apsnet.org)
- These toxin genes are parts of a cryptic prophage, the skin element, and of the prophage SPβ, respectively. (prolekare.cz)
- Prophages often carry genes that confer a selective advantage to the bacterium, typically during host colonization. (prolekare.cz)
- Prophages can convert to infectious viruses through a process known as induction, which is relevant to the spread of bacterial virulence genes. (prolekare.cz)
- The antirepressor genes lie outside the immunity region and are under direct control of the LexA repressor, thus plugging prophage induction directly into the SOS response. (prolekare.cz)
- Early studies also indicated that some genes of certain prophages escape lysogenic repression and express functions that modify the host bacterium. (asmscience.org)
- Genetic element Φ1207.3 (formerly Tn1207.3) is a prophage of Streptococcus pyogenes which carries the macrolide efflux resistance genes mef(A)/msr(D) and is capable of conjugal transfer among streptococci. (le.ac.uk)
- Characterization of this prophage has revealed that multiple genes are conserved with regard to both the DNA and protein sequences. (umaine.edu)
- Multiple structural genes including capsid and tail proteins are also conserved, suggesting the prophage may be capable of producing intact virions. (umaine.edu)
- At least two prophage genes are transcriptionally active. (umaine.edu)
- Expression of these genes suggests that the prophage does indeed have some potential for affecting the biology of the host bacterium. (umaine.edu)
- The role of prophages in the pathogenic life cycle of B. anthracis is not known and the majority of the genes on the B. anthracis prophages do not have an assigned function. (biomedcentral.com)
- For bioinformaticians, prophages are typically only found by looking for genes with homology. (phantome.org)
- There was limited evidence for genes shared between prophage clusters. (ox.ac.uk)
- 72% of prophages possessed the virulence genes pblA and/or pblB. (ox.ac.uk)
- Overall, pneumococcal prophages were highly prevalent, demonstrated a structured population, possessed genes associated with virulence, and were expressed under experimental conditions. (ox.ac.uk)
- It was therefore proposed that these strains had deletions which removed all or part of the PBSX prophage together with adjacent bacterial DNA encoding the pro ( AB ) and metC genes. (microbiologyresearch.org)
- A prophage generally occupies a specific locus in a bacterial chromosome and is inherited like ordinary bacterial genes. (thefreedictionary.com)
- BR7 also showed increased expression of genes involved in amino acid metabolism and transport, while BR21 showed increased expression of genes involved in iron acquisition and metabolism and in prophage genes. (thefreedictionary.com)
- To obtain efficient recombination of linear donor DNA in recA + or recA − backgrounds, an E. coli strain was made that contains a λ prophage harboring the recombination genes exo , bet , and gam under control of a temperature-sensitive λ cI-repressor (Fig. 1 ). (pnas.org)
- The transfer of these cells from 32°C to 42°C leads to rapid and coherent induction and expression of prophage genes. (nih.gov)
- The altered distribution of RpoZ-defective RNAP was identified mostly within open reading frames, in particular, of the genes inside prophages. (asm.org)
- After analysis of genomewide distribution of wild-type and RpoZ-defective RNAP by the ChIP-chip method, we found alteration of the RpoZ-defective RNAP inside open reading frames, in particular, of the genes within prophages. (asm.org)
- All the observations here described indicate the involvement of RpoZ in recognition of some of the prophage genes. (asm.org)
- We found that accessory genes of ATCC 27853 including prophages and genomic islands (GIs) mainly contribute to the difference between P. aeruginosa ATCC 27853 and other P. aeruginosa strains. (biomedcentral.com)
- 90% of the induced A. baumannii genes were clustered in three prophage regions, and bacteriophage particles were observed after mitomycin C treatment. (moreheadstate.edu)
- These prophages encoded esvI, esvK1, and esvK2, ethanol-stimulated virulence genes previously identified in a Caenorhabditis elegans model, as well as error-prone polymerase alleles. (moreheadstate.edu)
- The induction of all 17978 error-prone polymerase alleles, whether prophage-encoded or not, was recA dependent, but only these DNA polymerase V-related genes were de-repressed in the umuDAb mutant in the absence of DNA damage. (moreheadstate.edu)
- All 3 prophages were significantly similar to GAS prophages that carry virulence factor genes, indicating that these prophages had transferred these genes between pathogens. (biomedsearch.com)
- Analysis using the prophage database (http//bicmku.in8082) constructed by us showed 47 prophages were associated with putative two component cell lysis genes . (bvsalud.org)
- In this process, a putative holin (essd) and endolysin (ybcS), encoded by the defective lambdoid prophage DLP12 was found to be similar to two component cell lysis genes in functional bacteriophages like p21 and P1. (bvsalud.org)
- Temperate bacteriophages can integrate their genomes into the bacterial host chromosome and exist as prophages whose gene products play key roles in bacterial fitness and interactions with eukaryotic host organisms. (asm.org)
- The name bacteriophage encompasses all bacterial viruses, including temperate phages which have the particularity to integrate their genomes into their hosts, becoming prophages. (mdpi.com)
- We detected 154 different prophages in S. enterica genomes. (frontiersin.org)
- Prophages are encoded in most genomes of sequenced Clostridium difficile strains. (asm.org)
- Many species of bacteria harbor multiple prophages in their genomes. (prolekare.cz)
- Here we show that a large family of lambdoid prophages found in Salmonella genomes employs an alternative induction strategy. (prolekare.cz)
- The results indicated that functional prophage genomes may be a common constituent of all bacterial genomes of the investigated strains. (semanticscholar.org)
- We have identified the prophages in the complete genomes, and we provide that data for you. (phantome.org)
- Download prophage prediction s for selected genomes. (phantome.org)
- These are the genomes where we have reliable training sets of what prophages should look like. (phantome.org)
- Download predicted prophage proteins from all genomes. (phantome.org)
- Nearly 500 pneumococcal genomes were investigated and RNA sequencing was used to explore prophage gene expression. (ox.ac.uk)
- 1,300 genomes of 70 different Streptococcus species for evidence of prophages and identified nearly 800 prophages and satellite prophages, the majority of which are reported here for the first time. (ox.ac.uk)
- Here we report that over one-third of pneumococcal genomes possessed satellite prophages and demonstrate for the first time that a satellite prophage was associated with virulence in a murine model of infection. (ox.ac.uk)
- Pathogenic species of the bacterial genus Mycobacterium , including M. tuberculosis , carry these integrated viral genomes (prophage) that are hypothesized to contribute to virulence. (maineidea.net)
- Prophages are integrated forms of bacteriophages in bacterial genomes providing a repertoire for bacterial evolution. (bvsalud.org)
- Upon detection of host cell damage, such as UV light or certain chemicals, the prophage is excised from the bacterial chromosome in a process called prophage induction. (wikipedia.org)
- The variety of types suggests that the cryptic prophage is mutagenized as a consequence of the induction process. (genetics.org)
- Importantly, for lysogenic conversion to occur, it is not necessary that the prophage remains functional as a virus that is capable of prophage induction or lytic growth. (asmscience.org)
- An induction mechanism which involves recombination at the prophage insertion site is proposed to explain these differences. (asm.org)
- In this report, using bacteriophage λ and Shiga toxin-converting bacteriophage ϕ24Β, we demonstrate that the presence of this region on a multicopy plasmid results in impaired lysogenization of Escherichia coli and delayed, while more effective, induction of prophages following stimulation by various agents (mitomycin C, hydrogen peroxide, UV irradiation). (nih.gov)
- Spontaneous induction of λ and ϕ24Β prophages was also more efficient in bacteria carrying additional copies of the corresponding exo-xis region on plasmids. (nih.gov)
- Induction of prophages λ (left-side diagrams) and ϕ24B (right-side diagrams) in MG1655 hosts bearing the pJW0tet vector (closed squares) or either pGAW3775tet (left-side diagrams) or pSBe.x.r.ϕ24B (right-side diagrams) (open squares), treated with 0.2 μg/ml mitomycin C (a), 50 J/m2 UV irradiation (b), or 1 mM H2O2 (c) at time 0. (nih.gov)
- We found that induction of the ϕ24B prophage was delayed by 30-60 min in the presence of the exo-xis region on a multicopy plasmid, but this process was finally more efficient than that in control experiments, as more progeny phages were produced (Fig. 4). (nih.gov)
- This phenomenon occurred irrespective of the kind of the inducer used, nevertheless, the delay in prophage induction was the longest (60 min) in experiments with mitomycin C (Fig. 4). (nih.gov)
- Contrary to ϕ24B, effects of the exo-xis region on λ prophage induction depended on the nature of the inducing agent. (nih.gov)
- Nevertheless, with exception of the induction with mitomycin C, final efficiency of induction of λ prophage was higher in the presence of the exo-xis region on a plasmid relative to control experiments (Fig. 4). (nih.gov)
- We therefore provide, for the first time, evidence of in vivo prophage induction during CDI. (asm.org)
- We determined the minimum concentration required for prophage induction and the maximum prophage induction frequency for each carcinogen. (aspetjournals.org)
- The ability of antirepressors to recognize non-cognate repressors allows coordination of induction of multiple prophages in polylysogenic strains. (prolekare.cz)
- Results: Lysogen cultures propagated for 5-6 hours produced a high cell density with a low proportion of spontaneous prophage induction events. (ufl.edu)
- SOS-induced spontaneous prophage induction in Corynebacterium glutamicum", Presented at the EMBL Heidelberg "New Approaches and Concepts in Microbiology", Heidelberg, Germany, 2013. (uni-bielefeld.de)
- SOS-induced spontaneous prophage induction in Corynebacterium glutamicum", Presented at the Nikon Symposium on Advanced Imaging in Cell- and Microbiology Technology and Applications, Jülich, Germany, 2013. (uni-bielefeld.de)
- Induction with mitomycin C increased the frequency of excision of one of the prophages by approximately 250 fold. (biomedcentral.com)
- Heat-resistant derivatives of a Bacillus subtilis 168 strain carrying an xhi mutation, which causes heat-sensitive induction of the PBSX prophage, have been isolated and screened for the acquisition of auxotrophy. (microbiologyresearch.org)
- Lysogeny and prophage induction in coastal and offshore bacterial communities. (thefreedictionary.com)
- Host responses influence on the induction of lambda prophage. (nih.gov)
- Prophage induction can be initiated either by DNA damage or by heat treatment of a temperature-sensitive repressor. (nih.gov)
- Prophage induction by heat shock at 42°C.A. Strains W3110 (λcI857knR) carrying the pR-gfp (orange), the pE-gfp (blue) or the pR′-tR′-gfp (red) plasmids were grown exponentially in minimal medium, heat induced at 42°C for 5, 10 or 15 min (light to darker colours respectively), and assayed for fluorescence at 32°C for the indicated times. (nih.gov)
- Spontaneous prophage induction in a small subpopulation of cells which takes place in the absence of a known stimulus is an often observed, but poorly understood phenomenon. (tu-bs.de)
- With the proposed project we aim to investigate the impact of stress responses and stochasticity fluctuations of key regulatory proteins on the spontaneous induction of the Corynebacterium glutamicum prophage CGP3 at the single cell level. (tu-bs.de)
- We aim to combine classical microbiological approaches with stochastic modelling and the design of novel microfluidic devices for single cell studies to contribute to a better understanding of spontaneous prophage induction as a general phenomenon in bacterial populations. (tu-bs.de)
- Toxin gene expression in double lysogens was in excess of the single lysogen counterpart, both in the prophage state and after induction of the lytic life cycle. (microbiologyresearch.org)
- Prophage Induction and Differential RecA and UmuDAb Transcriptome Regu" by Janelle M. Hare, Joshua C. Ferrell et al. (moreheadstate.edu)
- The instance Induction of prophage lambda by chlorinated organics : detection of some single-species/single-site carcinogens, David M. DeMarini and Harold G. Brooks, (microform) represents a material embodiment of a distinct intellectual or artistic creation found in University of Missouri Libraries . (missouri.edu)
- have found that most TSS strains harbour prophages with common plating characteristics and suggest that the toxin(s) involved in TSS are transmitted by lysogenic conversion. (nih.gov)
- Prophage was induced when strains of Bacillus subtilis 168 lysogenic for φ105c4 were grown to competence and exposed to specific bacterial DNAs. (asm.org)
- In this study, the prophage sequence diversity in different Salmonella serovars and genetically related strains was investigated. (frontiersin.org)
- While some prophage sequences were highly conserved among the strains of specific serovars, few regions were lineage specific. (frontiersin.org)
- Therefore, strains belonging to each serovar could be clustered separately based on their prophage content. (frontiersin.org)
- Some mammalian carcinogens and their metabolites affect the viability of Salmonella typhimurium strains, as indicated by a decrease in colony formation, and also induce prophage. (aspetjournals.org)
- The majority of these phages are not amenable to propagation, and therefore the development of a molecular marker is a useful tool with which to establish the extent and diversity of C. difficile prophage carriage within clinical strains. (asm.org)
- This study reveals the high incidence of prophage carriage in clinically relevant strains of C. difficile and correlates the molecular data to the morphological observation. (asm.org)
- Interestingly, we found that the wt ϕRs551-carrying strain UW551 of R. solanacearum significantly outcompeted the wt strain RUN302 which lacks the prophage in tomato plants co-inoculated with the two strains. (frontiersin.org)
- Enteric species like E. coli and Salmonella typically contain multiple resident prophages whose variability in number and assortment constitutes a major source of diversity between strains - . (prolekare.cz)
- The retention of all four putative prophage regions across all tested strains of B. anthracis is further evidence of the very recent emergence of this lineage and the prophage regions may be useful for differentiating the B. anthracis chromosome from that of its neighbors. (biomedcentral.com)
- The defective prophage can be moved to other strains and can be easily removed from any strain. (pnas.org)
- Although all the strains carry some kind of prophage, or cryptic prophages. (coursera.org)
- The presence of a defective prophage in an industrial strain could provide superinfection immunity to the host but could also contribute DNA in recombination events to produce new phages potentially infective for the host strain in a large-scale fermentation environment. (environmental-expert.com)
- Recent studies have highlighted the great diversity of prophages in the clinical isolates of C. difficile ( 17 , 36 , 42 ), but only 5 fully characterized phages with complete genomic sequences are available in public databases. (asm.org)
- GfoA and GfhA, the antirepressors of Salmonella prophages Gifsy-1 and Gifsy-3, each target both of these phages' repressors, GfoR and GfhR, even though the latter proteins recognize different operator sites and the two phages are heteroimmune. (prolekare.cz)
- As an intracellular bacterium, ' Candidatus Liberibacter asiaticus' (Las) lacks known transposons and IS elements but contains at least two prophages/phages. (escholarship.org)
- We undertook this study in order to understand whether the four prophages are unique to B. anthracis and whether they produce active phages. (biomedcentral.com)
- Typing phages and prophages of Salmonella . (cdc.gov)
- The prophages of certain bacterial phages an. (bookrags.com)
- Prophage is the deoxyribonucleic acid (DNA) of a temperate bacteriophage combined with the DNA of a lysogenized bacterium. (thefreedictionary.com)
- It is unclear whether all of these putative prophages are active, although one (ΦK96243) was shown to be a productive bacteriophage. (beds.ac.uk)
- Prophage-triggered membrane vesicle formation through peptidoglycan damage in Bacillus subtilis. (sigmaaldrich.com)
- The structure of Bacillus subtilis SPβ prophage dUTPase and its complexes with two nucleotides. (ox.ac.uk)
- Bacillus subtilis has both a genomic and an SPβ prophage homotrimeric dUTPase. (ox.ac.uk)
- In molecular biology, the YqaJ refers to the YqaJ/K domain from the skin prophage of the bacterium, Bacillus subtilis. (wikipedia.org)
- Define plaque lysogeny and prophage stage. (alitcg.com)
- Crucial in the maintenance of lysogeny and prophage stability. (alitcg.com)
- Answer to Define plaque, lysogeny, and prophage. (alitcg.com)
- In this study, we revealed the genetic diversity and population dynamics of this bacterium based on two prophage hyper-variable regions (HVRs) using separate libraries constructed from citrus, periwinkle and psyllid. (escholarship.org)
- Secondly, the concept of prophage was applied to resemble obfuscation technique virus DNA during the injection process in the operating system files, similar injection of a virus in a bacterium. (thefreedictionary.com)
- This bacterium is so closely associated with prophages that it is rare to find S. aureus isolates without prophages. (elsevier.com)
- Preliminary analyses confirmed that the sequences of the three prophages diverge considerably in the portion corresponding to the immunity module. (asmscience.org)
- The two HVRs, Type A and B, share highly conserved sequences and are localize to the two prophages, FP1 and FP2, respectively. (escholarship.org)
- More than 300 geographically and temporally divergent isolates of B. anthracis and its near neighbors were screened by PCR for the presence of specific DNA sequences from each prophage region. (biomedcentral.com)
- The defective prophage pool of Escherichia coli O157: prophage-prophage interactions potentiate horizontal transfer of virulence determinants. (thefreedictionary.com)
- Recombination directionality factors (RDFs), or excisionases, are essential players of prophage excisive recombination. (mdpi.com)
- Sequence analysis of these variants revealed the variations were due to the recombination and reassortment between two prophages. (escholarship.org)
- A temperature-dependent repressor tightly controls prophage expression, and, thus, recombination functions can be transiently supplied by shifting cultures to 42°C for 15 min. (pnas.org)
- The efficient prophage recombination system does not require host RecA function and depends primarily on Exo, Beta, and Gam functions expressed from the defective λ prophage. (pnas.org)
- The prevalence of prophages in a representative S. aureus strain collection consisting of 386 isolates of diverse origin was determined. (asm.org)
- Insights to the diphtheria toxin encoding prophages amongst clinical isolates of Corynebacterium diphtheriae from India. (nih.gov)
- Analysis of S . Enteritidis isolates from seven outbreaks generated distinct prophage profiles for each outbreak. (frontiersin.org)
- In this study, we performed spa typing and RSTing with 84 isolates from mastitic cows (22 farms, 72 cows, and 84 udders) and developed a molecular prophage typing (mPPTing) method for molecular epidemiological analysis of bovine mastitis. (bvsalud.org)
- Individual isolates of Burkholderia pseudomallei and B. thailandensis , for example, carry a variety of strain-specific genomic islands (GIs), including putative pathogenicity and metabolic islands, prophage-like islands, and prophages. (beds.ac.uk)
- Prophages are important agents of horizontal gene transfer, and are considered part of the mobilome. (wikipedia.org)
- Here we established a classification scheme for staphylococcal prophages of the major Siphoviridae family based on integrase gene polymorphism. (asm.org)
- which suggests the potential application of the holin gene to study prophage carriage in other bacteria. (asm.org)
- Spontaneously induced prophages in Lactobacillus gasseri contribute to horizontal gene transfer. (semanticscholar.org)
- RNA sequencing provided clear evidence of prophage gene expression. (ox.ac.uk)
- Through RNAseq analysis of both pathogenic ( M. chelonae ) and non-pathogenic ( M. smegmatis ) mycobacterial species, we have determined that prophage significantly affect host gene expression. (maineidea.net)
- This project aims to characterize the impact of prophage on mycobacterial fitness and virulence by exploring the role of prophage activity in altering host gene expression. (maineidea.net)
- this gene is known to be co-transducible with the PBSX prophage. (microbiologyresearch.org)
- In this research proposal, we test the hypothesis that prophages can increase staphylococcal virulence not only by providing virulence factors but also by altering bacterial gene expression. (elsevier.com)
- A remarkable amount of genotypic variation accumulated during clonal expansion that occurred during the epidemic, including multiple independent acquisitions of a novel prophage carrying the sopE gene and multiple deletion events affecting the phase II flagellin locus. (cdc.gov)
- GGS_124 contained 3 prophages, with one containing a virulence factor gene for streptodornase. (biomedsearch.com)
- Such targeted sequence- structure-function characterization of proteins encoded by cryptic prophages will help understand the contribution of prophage proteins to bacterial evolution. (bvsalud.org)
- Some prophages get stuck inside the bacteria, and eventually get deleted by natural selection. (phantome.org)
- However, in some growing lysogenic bacteria (approximately one cell per million), the prophage becomes infectious, that is, it becomes induced. (thefreedictionary.com)
- Individual lysogenic bacteria may carry several prophages. (thefreedictionary.com)
- Temperate Prophages Increase Bacterial Adhesin Expression and Virulence in an Experimental Model of Endocarditis Due to Staphylococcus aureus From the CC398 Lineage. (unil.ch)
- In S. aureus MSSA476, we found that enrichment and excision of the prophage ϕSa4ms into the cytoplasm was temporal and that episomal prophage localization did not appear to be a precursor to lytic cycle replication, suggesting ϕSa4ms excision into the cytoplasm may be part of a novel lysogenic switch. (umaryland.edu)
- This presents us with an alternative mechanism for the role of prophage in host virulence and pathogenicity. (maineidea.net)
- Subclassification and targeted characterization of prophage-encoded two-component cell lysis cassette. (bvsalud.org)
- The Corynebacterium glutamicum ATCC 13032 prophage CGP3 encodes an actin-like protein, AlpC that was shown to be involved in viral DNA transport and efficient viral DNA replication. (uni-muenchen.de)
- The prophage is passively replicated as part of the host chromosome as long as conditions are not threatening to the host, in which case the prophage shifts to a lytic development [ 3 , 4 , 5 ]. (mdpi.com)
- Interestingly, at the same locus in the B. cereus 14579 chromosome, is a defective prophage, phi6A53, with little similarity to B. anthracis lambdaBa0l. (biomedcentral.com)
- The DNA of a prophage is approximately 1/50 to 1/100 the size of the DNA of a bacterial chromosome and contains about 10 5 pairs of nucleotides. (thefreedictionary.com)
- A prophage is nonpathogenic for a bacterial cell and is replicated over many generations simultaneously with the bacterial chromosome. (thefreedictionary.com)
- For instance, 11% of the genomic DNA of strain 630 is made up of MGE, including 8 conjugative transposons and 2 functional and highly similar prophages ( 39 ). (asm.org)
- ZK, CP000001) revealed that prophages are generally inserted at different chromosomal loci than B. anthracis , except in B. cereus ZK strain that contains an element very similar to B. anthracis lambdaBa01 inserted at the same locus. (biomedcentral.com)
- Below are the list of possible Prophage antitermination protein products. (mybiosource.com)
- Also known as Prophage antitermination protein Q homolog QuuD (Antitermination protein Q homolog from lambdoid prophage DLP12). (mybiosource.com)
- Furthermore, identical prophages were found in the chromosomes of C. difficile isolated from the corresponding fecal samples. (asm.org)
- Prophage Lrm1 was induced with mitomycin C from an industrial Lactobacillus rhamnosus starter culture, M1. (environmental-expert.com)
- Here we present the results of analysis of 37 prophages, putative prophages, and prophage-like elements from six different Burkholderia species. (beds.ac.uk)
- Three-dimensional structure of the toxin-delivery particle antifeeding prophage of Serratia entomophila. (nih.gov)
- The Serratia entomophila antifeeding prophage (Afp) is a bullet-shaped toxin-delivery apparatus similar to the R-pyocins of Pseudomonas aeruginosa. (nih.gov)
- Here, we characterize the antifeeding prophage AFP from Serratia entomophila by cryo-electron microscopy. (pdbj.org)
- Sewell, Erica, "Characterizing the Intact Prophage of Mycobacterium chelonae Bergey" (2017). (umaine.edu)
- Welcome to the Prophage blog 2017! (blogspot.hr)
- The Prophage Hp1 Hol (Hp1Hol) Family (TC# 1.E.46) consists of a single putative holin (TC# 1.E.46.1.1) of 69 amino acyl residues in length, exhibiting what appears to be a single transmembrane segment (TMS). (wikipedia.org)
- Prophage repertoires provide an additional marker for differentiating S. enterica subtypes during foodborne outbreaks. (frontiersin.org)
- The fitness costs depend on the activity of prophage-internal promoters and type III-A Cas nucleases implicated in targeting, can be more severe in double lysogens, and are alleviated by spacer-target mismatches which do not abrogate immunity during the lytic cycle. (elsevier.com)
- Since all 10 prophages in E. coli K-12 carry only a small number of promoters, the altered occupancy of RpoZ-defective RNAP and of transcripts might represent transcription initiated from as-yet-unidentified host promoters. (asm.org)
- This study advances understanding of not only the regulatory role of omega subunit in the functions of RNAP but also the regulatory interplay between prophages and the host E. coli for adjustment of cellular physiology to a variety of environments in nature. (asm.org)
- Temperate bacteriophages are common and establish lysogens of their bacterial hosts in which the prophage is stably inherited. (asm.org)
- Among the large collection of sequenced mycobacteriophages, more than half are temperate or predicted to be temperate, most of which code for a tyrosine or serine integrase that promotes site-specific prophage integration. (asm.org)
- Determining how prophage within non-tuberculosis pathogenic mycobacteria contribute to virulence will provide opportunities to develop and improve treatment of bacterial diseases. (maineidea.net)