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

A novel bacterium, designated as strain AM134T, was isolated from the gut of a purple sea urchin (Heliocidaris crassispina) gathered from the coastal waters of Dokdo, Korea. Strain AM134T was Gram-stain-negative, both catalase- and oxidase-positive, strictly aerobic and showed a rod-coccus cell cycle. Optimum growth occurred at 30 °C, in the presence of 2 % (w/v) NaCl and at pH 7. The 16S rRNA gene sequence analysis showed that strain AM134T belonged to the genus Microbulbifer in the family Alteromonadaceae and had high 16S rRNA gene sequence similarity (>97 %) with Microbulbifer epialgicus F-104T (98.9 % similarity) and Microbulbifer variabilis Ni-2088T (98.6 % similarity). The polar lipid profile of strain AM134T 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 (C18 : 1ω6c and/or C18 : 1ω7c) and C16 : 0. The DNA-DNA hybridization analysis showed that the strain shared less than 28 % genomic relatedness with Microbulbifer epialgicus DSM 18651T (27±3 %) and Microbulbifer variabilis ATCC 700307T (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 AM134T represents a novel species in the genus Microbulbifer, for which the name Microbulbifer echini is proposed. The type strain is AM134T (=KACC 18258T=JCM 30400T).

Arthrobacter echini sp. nov., isolated from the gut of a purple sea urchin, Heliocidaris crassispina.

A novel strain, designated AM23T, was isolated from the gut of a purple sea urchin Heliocidaris crassispina collected from the coastal waters of the Korean island Dokdo. 16S rRNA gene sequence analysis showed that strain AM23T belonged to the genus Arthrobacter in the family Micrococcaceae and shared highest sequence similarity with Arthrobacter agilis DSM 20550T (98.77%). Strain AM23T was catalase-positive, oxidase-negative and grew optimally at 20 °C, in the presence of 1% (w/v) NaCl and at pH 7. The isolate was a Gram-stain-positive, non-motile, strictly aerobic and coccus-shaped bacterium. The major cellular fatty acids were anteiso-C15:0 and iso-C15:0. The polar lipids of strain AM23T were phosphatidylglycerol, diphosphatidylglycerol, phosphatidylinositol, one unidentified glycolipid and four unidentified lipids. The components of the cell-wall peptidoglycan were lysine, glutamic acid and alanine and the predominant cell-wall sugars were galactose, mannose, rhamnose and ribose. The major respiratory quinone was identified as menaquinone MK-9(H2). The genomic DNA G+C content was 67.3 mol% and the DNA-DNA hybridization values showed the strain shared less than 29% genomic relatedness with A. agilis DSM 20550T. The results of the phylogenetic, phenotypic and genotypic analysis indicate that strain AM23T represents a novel species in the genus Arthrobacter, for which the name Arthrobacter echini sp. nov. is proposed. The type strain is AM23T (=KACC 18260T=DSM 29493T).