Microbulbifer echini sp nov., isolated from the gastrointestinal tract of a purple sea urchin, Heliocidaris crassispina

A novel bacterium, designated as strain AM134(T), was isolated from the gut of a purple sea urchin (Heliocidaris crassispina) gathered from the coastal waters of Dokdo, Korea. Strain AM134(T) was Gram-stain-negative, both catalase-and oxidasepositive, strictly aerobic and showed a rod-coccus cell cycle. Optimum growth occurred at 30 degrees C, in the presence of 2% (w/v) NaCl and at pH 7. The 16S rRNA gene sequence analysis showed that strain AM134(T) belonged to the genus Microbulbifer in the family Alteromonadaceae and had high 16S rRNA gene sequence similarity (>97 %) with Microbulbifer epialgicus F-104(T) (98.9% similarity) and Microbulbifer variabilis Ni-2088(T) (98.6% similarity). The polar lipid profile of strain AM134(T) was composed of phosphatidylethanolamine, phosphatidylserine, three unidentified aminophospholipids, two unidentified phospholipids, an unidentified amino lipid and six unidentified lipids. The major respiratory quinone was identified as ubiquinone-8 (Q-8). The major cellular fatty acids were summed feature 8 (C-18 : 1 omega 6c and/or C-18 : 1 omega 7c) and C-16 : 0. The DNA-DNA hybridization analysis showed that the strain shared less than 28% genomic relatedness with Microbulbifer epialgicus DSM 18651 T (27 +/- 3 %) and Microbulbifer variabilis ATCC 700307(T) (15 +/- 1 %). The G+C content of the genomic DNA was 56.1 mol%. The results of the phylogenetic, phenotypic and genotypic analyses suggest that strain AM134(T) represents a novel species in the genus Microbulbifer, for which the name Microbulbifer echini is proposed. The type strain is AM134(T) (= KACC 18258(T) = JCM 30400(T)).