FILAMENTOUS BACTERIOPHAGES OF VIBRIO-PARAHAEMOLYTICUS AS A POSSIBLE CLUE TO GENETIC TRANSMISSION

We have previously reported the isolation and characterization of two filamentous bacteriophages of Vibrio parahaemolyticus, designated Vf12 and Vf33. In this study, to understand the potential of these phages as tools for genetic transmission,,ve investigated the gene structures of replicative-form (RF) DNAs of their genomes and the distribution o f these DNAs on chromosomal and extrachromosomal DNAs, The 7,965-bp nu cleotide sequences of Vf12 and Vf33 were determined, An analysis of th e overall gene structures revealed that Vf12 and Vf33 had conserved re gions and distinctive regions. The gene organization of their conserve d regions was similar to that of CTS phage of Vibrio cholerae and coli phage Ff of Escherichia coli, while their distinctive regions,were cha racteristic of Vf12 and Vf33 phage genomes. Southern blot hybridizatio n testing revealed that the filamentous phage genomes integrated into chromosomal DNA of V. parahaemolyticus at the distinctive region of th e phage genome and were also distributed on some plasmids of V. paraha emolyticus and total cellular DNAs of one Vibrio damsela and one nonag glutinable Vibrio strain tested. These results strongly suggest the po ssibilities of genetic interaction among the bacteriophage Vf12 and Vf 33 genomes and chromosomal and plasmid-borne DNAs of V. parahaemolytic us strains and of genetic transmission among strains through these fil amentous phages.