Prophage


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prophage

[′prō‚fāj]
(virology)
Integrated unit formed by union of the provirus into the bacterial genome.

Prophage

 

a latent, or occult, noninfectious form of temperate bacteriophage that is present in lysogenic bacteria.

Prophage is the deoxyribonucleic acid (DNA) of a temperate bacteriophage combined with the DNA of a lysogenized bacterium. The DNA of a prophage is approximately 1/50 to 1/100 the size of the DNA of a bacterial chromosome and contains about 105 pairs of nucleotides. Thus, a prophage is a complete genome of a phage and contains about 100 genes.

A prophage generally occupies a specific locus in a bacterial chromosome and is inherited like ordinary bacterial genes. 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. The location of a prophage is genetically controlled by its special region, which constitutes about 1/15 of the total length of the genome.

A prophage is nonpathogenic for a bacterial cell and is replicated over many generations simultaneously with the bacterial chromosome. However, in some growing lysogenic bacteria (approximately one cell per million), the prophage becomes infectious, that is, it becomes induced. As a result of induction, it is converted into an intracellular vegetative phage that is not bound to the bacterial chromosome. When this type of phage replicates, the bacterial cell undergoes lysis and dies. Individual lysogenic bacteria may carry several prophages.

A. V. KOLOBOV

References in periodicals archive ?
The defective prophage pool of Escherichia coli O157: prophage-prophage interactions potentiate horizontal transfer of virulence determinants.
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.
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.
Briissow, "The prophage sequences of Lactobacillus plantarum strain WCFS1," Virology, vol.
Subsystem feature Subsystem category counts Sulfur metabolism 32 Phosphorus metabolism 47 Carbohydrates 242 Amino acids and derivatives 417 Fatty acids, lipid, and isoprenoids 103 Metabolism secondary 4 Nitrogen metabolism 13 Metabolism of aromatic compounds 24 Cofactors, vitamins, prosthetic groups, and pigments 242 Nucleosides and nucleotides 90 Dormancy and sporulation 1 Respiration 133 Stress response 134 DNA metabolism 99 Membrane transport 156 Regulation and cell signaling 88 Motility and chemotaxis 176 Cell division and cell cycle 35 Protein metabolism 298 RNA metabolism 135 Iron acquisition and metabolism 34 Phages, prophages, transposable elements and plasmids 65 Miscellaneous 45 Photosynthesis 0 Potassium metabolism 20 Virulence, disease, and defense 88 Cell wall and capsule 166
(2011) CRISPR Inhibition of Prophage Acquisition in Streptococcus pyogenes.
Many EHEC 0157 strains have both VT1 and VT 2 genes in the genome of prophage of [lambda] bacteriophage [37].
Agenus' heat shock protein vaccine, Prophage, has successfully completed Phase 2 studies in newly diagnosed glioblastoma multiforme.
coli O157:H7 is associated with a prophage. (7) Different subtypes of shiga toxin are identified as stx1, stx1c, stxfc, stx2, stx2e, stx2d and stx2g.
Stein added that it is rational to combine CPMs such as CTLA-4 and PD-1 antagonists with anti-cancer vaccines, and that the company is collaborating on an ongoing Phase II study assessing Prophage and Yervoy (CTLA-4 antagonist) in patients with metastatic melanoma.
Typhimurium emerged which contained the SopE virulence gene within a prophage. SopE encodes for a SPI-1 T3S effector protein, which stimulates immune signaling pathways and also inflammation of the gastrointestinal tract [116, 119].