Halocynthiibacter namhaensis gen. nov., sp. nov., a novel alphaproteobacterium isolated from sea squirt Halocynthia roretzi

Abstract

A Gram-negative, non-motile and rod-shaped bacterial strain, designated RA2-3(T), was isolated from a sea squirt (Halocynthia roretzi) collected from the South Sea, Korea, and its taxonomic position was investigated by using a polyphasic approach. Strain RA2-3(T) was observed to grow optimally at 25 °C, at pH 7.0-7.5 and in the presence of 2 % (w/v) NaCl. Strain RA2-3(T) exhibited the highest 16S rRNA gene sequence similarity values to the type strains of Litoreibacter meonggei (95.7 %), Planktotalea frisia (95.6 %), Thalassobius gelatinovorus (95.5 %) and Pelagicola litoralis (95.4 %). A neighbour-joining phylogenetic tree based on 16S rRNA gene sequences revealed that strain RA2-3(T) clustered with the type strains of Planktotalea frisia, Pelagicola litoralis, Pacificibacter maritimus and Roseovarius marinus. Strain RA2-3(T) was found to contain Q-10 as the predominant ubiquinone and C18:1 ω7c as the major fatty acid. The major polar lipids detected in strain RA2-3(T) were phosphatidylcholine, phosphatidylglycerol, one unidentified aminolipid and one unidentified lipid. The DNA G+C content of strain RA2-3(T) was 52.9 mol%. On the basis of the phylogenetic, chemotaxonomic and phenotypic properties, strain RA2-3(T) is considered to represent a new genus and species within the family Rhodobacteraceae, for which the name Halocynthiibacter namhaensis gen. nov., sp. nov. is proposed. The type strain of H. namhaensis is RA2-3(T) (=KCTC 32362(T)=NBRC 109999(T)).

Pseudohalocynthiibacter aestuariivivens gen. nov., sp. nov., isolated from a tidal flat

“…The fatty acid profile of strain BS-W9 T was distinguished from that of the type strain of H. namhaensis by differences in the presence and proportions of some fatty acids, particularly cyclo C 19 : 0 ω8 c and 11-methyl C 18 : 1 ω7 c (). The fatty acid profile of strain BS-W9 T could also be distinguished from those of some phylogenetically related taxa, Pseudopelagicola gijangensis , Pelagicola litoralis and Ascidiaceihabitans donghaensis , particularly by the presence of cyclo C 19 : 0 ω8 c (; Kim et al , 2014a, b, c). The major polar lipids detected in strain BS-W9 T were phosphatidylcholine, phosphatidylethanolamine, phosphatidylglycerol, one unidentified lipid and one unidentified aminolipid; minor amounts of another unidentified lipid and one unidentified aminophospholipid were also present (Fig.…”

“…Comparative 16S rRNA gene sequence analysis showed that this novel strain is phylogenetically most closely related to the genus Halocynthiibacter of the family Rhodobacteraceae . The genus Halocynthiibacter was proposed by Kim et al (2014a) with the description of a single species with a validly published name, Halocynthiibacter namhaensis , which was isolated from a sea squirt collected from the South Sea, South Korea. The aim of the present work was to determine the exact taxonomic position of strain BS-W9 T by using a polyphasic characterization, which included determination of chemotaxonomic and other phenotypic properties, and detailed phylogenetic investigations based on 16S rRNA gene sequences and DNA–DNA hybridization.…”

“…Strain BS-W9 T was isolated by the standard dilution plating technique at 25 °C on marine agar 2216 (MA; BD) and cultivated routinely under the same culture conditions. H. namhaensis RA2-3 T , which was used as a reference strain for phenotypic characterization and DNA–DNA hybridization, was obtained from the study of Kim et al (2014a). Cell morphology and flagellation were examined by using light microscopy (BX51; Olympus) and transmission electron microscopy (JEM1010; JEOL), respectively.…”

“…The predominant isoprenoid quinone detected in strain BS-W9 T was ubiquinone-10 (Q-10), which is typical of the vast majority of the class Alphaproteobacteria ,including the genus Halocynthiibacter (Kim et al , 2014a). In , the cellular fatty acid profile of strain BS-W9 T is compared with that of the type strain of H. namhaensis grown and analysed under identical conditions (Kim et al , 2014a). The predominant fatty acid detected in strain BS-W9 T was C 18 : 1 ω7 c .…”

“…The polar lipid profile of strain BS-W9 T was distinguished from those of the type strains of H. namhaensis and Pseudopelagicola gijangensis in that phosphatidylethanolamine is present (Fig. S2; Kim et al , 2014a, b). The polar lipid profile of strain BS-W9 T was also distinguishable from those of the type strains of Pseudopelagicola gijangensis , Pelagicola litoralis and Ascidiaceihabitans donghaensis by the absence of diphosphatidylglycerol (Fig.…”