Bacteriophages attacking @entity5858 , a @entity880 bacterium used in milk fermentation, are a threat to the dairy industry. These small isometric-headed phages possess double-stranded DNA genomes of 31 to 45 kb. Yoghurt-derived phages exhibit a limited degree of variability, as defined by restriction pattern and host range, while a large diversity of phage types have been isolated from cheese factories. Despite this diversity all @entity5859 phages, virulent and temperate, belong to a single DNA homology group. Several mechanisms appear to create genetic variability in this phage group. Site-specific deletions, one type possibly mediated by a viral recombinase/integrase, which transformed a temperate into a virulent phage, were observed. Recombination as a result of superinfection of a lysogenic host has been reported. Comparative DNA sequencing identified up to 10% sequence diversity due to point mutations. Genome sequencing of the prototype temperate phage phi Sfi21 revealed many predicted proteins which showed homology with phages from @entity7878 suggesting horizontal gene transfer. Homology with phages from evolutionary unrelated bacteria like @entity526 (e.g. lambdoid phage 434 and P1) and Mycobacterium phi L5 was also found. Due to their industrial importance, the existence of large phage collections, and the whole phage genome sequencing projects which are currently underway, the @entity5859 phages may present an interesting experimental system to study bacteriophage evolution.

Molecular ecology and evolution of XXXX bacteriophages--a review.

@entity5859 :: ('2057', 'Species') :: ['S. thermophilus'] @entity880 :: ('MESH:D019344', 'Chemical') :: ['lactic acid'] @entity5858 :: ('1308', 'Species') :: ['Streptococcus thermophilus'] @entity7878 :: ('1358', 'Species') :: ['Lactococcus lactis'] @entity526 :: ('562', 'Species') :: ['E. coli']
@entity5858 :: (1308,Species) :: ['Streptococcus thermophilus']
