Taxonomical and serological studies on the causative bacteria of the disease of sea urchin strongylocentrotus intermedius occurring at low water temperatures

Abstract

Identification of the causative bacteria Vibrio spp., which were isolated from diseased sea urchin Strongylocentrotus intermedius and their rearing cages at low seawater temperatures at Date, Shiriuchi and Shikabe Fisheries Breeding Centers in Hokkaido was undertaken based on their biochemical properties, DNA-DNA homology and serological analysis. All fifteen strains, five from each Breeding Center were almost identical in biochemical properties except indole production. However, the strains isolated at Date differed from the strains at Shiriuchi and Shikabe in DNA-DNA homology and analysis of thermostable and thermolabile antigenic compositions. These results indicated that the strains from Shiriuchi and Shikabe belonged to the same species but they were different from those of Date. Moreover, the causative Vibrio spp. differed in biochemical, genotypical and serological properties from any strains of Vibrio spp. isolated from the intestine of healthy sea urchin and any of type strains of the genus Vibrio.