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Integrated unit formed by union of the provirus into the bacterial genome.



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.


References in periodicals archive ?
Unique genetic content and position was found for 9 putative prophages (Figure 1).
Diversity of Prophages in Dominant Staphylococcus aureus Clonal Lineages.
Prophage regions encode virulence factors such as exotoxins, (13) and the diversity of prophages might affect the variety in GAS pathogenicity.
SEA, a major leading cause of food poisoning, (29,30) is carried by prophage Sa3mu alone or by Sa3mw with other genes (seg and sek).
Prophages in marine bacteria: dangerous molecular time bombs or the key to survival in the seas?
There are over 13 effector proteins and a number of which are encoded outside of SPI-1, including SPI-5 and prophages.
These CT genes are carried by a prophage designated CTX[PHI] that forms filamentous non-lytic particles (14).
Variable assortment of prophages provi des a transferable repertoire of pathogenic determinants in lysogenic conversion is a major mechanism driving the evolution of Salmonella bacteria.
aureus and is brought about mainly by insertion of insertion sequences, transposons, prophages, and incompletely understood events.
The 17 papers here reflect these and other advances, including new technologies of detection and detection of resistance, physical mapping of genomes, genome-based identification and molecular analysis, microarray analysis in genetic research, manipulation of large bacterial DNA segments, amplified fragment length polymorphism analysis, phages and prophages (and their practical aspects), applications of cell imaging, kinesin accumulation, transport assays in intact cells, methods in cell-to-cell signaling, development of strains as cancer therapy agents, and further resources for molecular protocols in research.
Using a chemical stimulant, his team coaxed the prophages to mutate into a new form that destroyed the bacteria.