Publication Date:
2012-06-11
Description:
Background: Vibrio parahaemolyticus is associated with gastroenteritis, wound infections, and septicemiain human and animals. Phages can control the population of the pathogen. So far, the onlyone reported genome among giant vibriophages is KVP40: 244,835 bp with 26% codingregions that have T4 homologs. Putative homing endonucleases (HE) were found in Vibriophage KVP40 bearing one segD and Vibrio cholerae phage ICP1 carrying one mobC/E andone segG. Results: A newly isolated Vibrio phage phipp2, which was specific to the hosts of V. parahaemolyticusand V. alginolyticus, featured a long nonenveloped head of ~90 x 150 nm and tail of ~110nm. The phage can survive at 50degreesC for more than one hour. The genome of the phage phipp2was sequenced to be 246,421 bp, which is 1587 bp larger than KVP40. 383 protein-encodinggenes (PEGs) and 30 tRNAs were found in the phage phipp2. Between the genomes of phipp2and KVP40, 254 genes including 29 PEGs for viral structure were of high similarity, whereas17 PEGs of KVP40 and 21 PEGs of phipp2 were unmatched. In both genomes, the capsid andtail genes have been identified, as well as the extensive representation of the DNAreplication, recombination, and repair enzymes. In addition to the three giant indels of 1098,1143 and 3330 nt, phipp2 possessed unique proteins involved in potassium channel, gp2 (DNAend protector), tRNA nucleotidyltransferase, and mob-type HEs, which were not reported inKVP40. The phipp2 PEG274, with strong promoters and translational initiation, was identifiedto be a mobE type, flanked by NrdA and NrdB/C homologs. Coincidently, several pairs ofHE-flanking homologs with empty center were found in the phages of Vibrio phages phipp2and KVP40, as well as in Aeromonas phages (Aeh1 and Ae65), and cyanophage P-SSM2. Conclusions: Vibrio phage phipp2 was characterized by morphology, growth, and genomics with three giantindels and different types of HEs. The gene analysis on the required elements fortranscription and translation suggested that the phipp2 PEG274 was an active mobE gene. Thephage was signified to be a new species of T4-related, differing from KVP40.
Electronic ISSN:
1471-2164
Topics:
Biology
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