Jannaschia cystaugens sp. nov., an Alexandrium (Dinophyceae) cyst formation-promoting bacterium from Hiroshima Bay, Japan.

Heterotrophic bacteria isolated from water samples taken from Hiroshima Bay, Japan, and referred to as Alexandrium (Dinophyceae) cyst formation-promoting bacteria, were assigned to the Roseobacter-Sulfitobacter-Silicibacter group within the alpha-Proteobacteria on the basis of nearly complete 16S rRNA gene sequences. Phylogenetic analyses showed that two strains, CFPB-A9T and CFPB-A5, are closely related to each other and that their closest relative was Jannaschia helgolandensis (95.9 % sequence similarity).

Population structure of Alexandrium (Dinophyceae) cyst formation-promoting bacteria in Hiroshima Bay, Japan.

A total of 31 bacterial isolates that have potential Alexandrium cyst formation-promoting activity (Alex-CFPB) were isolated from Hiroshima Bay (Japan), which is characterized by seasonal blooms of the toxic dinoflagellate Alexandrium tamarense. The population structure of Alex-CFPB was analyzed by means of restriction fragment length polymorphism analysis of the 16S rRNA genes (16S rDNA). Fourteen ribotypes, A to N, were observed among the 31 isolates of Alex-CFPB by using four restriction enzymes, MboI, HhaI, RsaI and BstUI.