GENETIC DIVERSITY OF RELATED VIBRIOPHAGES ISOLATED FROM MARINE ENVIRONMENTS AROUND FLORIDA AND HAWAII, USA

Although viruses from the marine environment have been enumerated, iso lated, and characterized, there is little information on the abundance or global distribution of specific phage types. To this end, we studi ed the abundance and distribution of phages which infect a marine bact erium isolated from Tampa Bay (Florida, USA), tentatively identified ( Microbial ID, Inc., Newark, Delaware, USA) as Vibrio parahaemolyticus. Using this host, we have isolated over 60 phages from the Gulf of Mex ico, Tampa Bay, Florida Keys, and Oahu, Hawaii (USA). These isolates a re all Myoviridae, with head sizes ranging from 50 +/- 0.0 to 65 +/- 4 .2 nm and tail lengths of 60 +/- 3.6 to 100 +/- 5.0 nm. The type phage (Phi 16 from Tampa Bay) has a double-stranded DNA genome of 51 to 58 kb. A 1.5 kb EcoRI fragment of this genome has been cloned and used as a gene probe. All of the DNA from the phage isolates hybridized to th is probe under stringent conditions, but not to DNA from other marine vibriophages and bacteriophages, suggesting genetic relatedness. Agaro se gel electrophoresis of EcoRI digests of the DNAs, followed by South ern transfer and probing with the 1.5 kb gene probe, yielded 6 groups based upon banding patterns. These groups were not segregated geograph ically within the Florida isolates; however, all of the Hawaiian phage s had a common restriction pattern. These data indicate that populatio ns of genetically related phages are widely distributed over large geo graphic distances in the oceans.