Restriction fragment length polymorphism analysis of psychrophilic and psychrotrophic Vibrio and Photobacterium from the north-western Pacific Ocean and Otsuchi Bay, Japan

Typing and identification of 60 marine psychrophilic and psychrotrophic vib rios isolated from the northwestern Pacific Ocean and coastal environment o f Japan were performed by restriction fragment length polymorphism analysis on the basis of polymerase chain reaction amplified 16S rDNA. We obtained 15 operational taxonomic units (OTUs) by digestion with four restriction en donucleases (HhaI, DdeI, RsaI, and Sau3AI); four large groups were obtained from the neighbor-joining method. Significant differences were observed in OTU composition between isolates from the deep sea and coastal areas. Vibr io marinus and Photobacterium species were the dominant culturable vibrios in the deep sea areas, while Vibrio splendidus like species were the domina nt culturable vibrios in a coastal area of Japan.