Cyclobacterium qasimii sp. nov., a psychrotolerant bacterium isolated from Arctic marine sediment.

A novel Gram-stain-negative, horseshoe-shaped, non-motile bacterium, designated strain M12-11B(T), was isolated from a marine sediment sample collected at a depth of 200 m from Kongsfjorden, Svalbard. The colony colour was orangish red due to the presence of carotenoids. Fatty acids were dominated by branched and unsaturated fatty acids (90.8 %), with a high abundance of iso-C(15 : 0) (14.9 %), anteiso-C(15 : 0) (11.4 %), iso-C(15 : 1) G (13.1 %), C(15 : 1)ω6c (5.4 %), C(17 : 1)ω6c (6.7 %), summed feature 3 (C(16 : 1)ω7c and/or C(16 : 1)ω6c; 9.3 %) and summed feature 9 (10-methyl C(16 : 0) and/or iso-C(17 : 1)ω9c; 5.9 %). Strain M12-11B(T) contained MK-7 as the major respiratory quinone. The polar lipids consisted of phosphatidylcholine, phosphatidylethanolamine, one unidentified aminolipid and three unidentified lipids. Based on 16S rRNA gene sequence similarities, the type strains of Cyclobacterium amurskyense, Cyclobacterium marinum and Cyclobacterium lianum were most closely related to M12-11B(T) with sequence similarities of 98.2, 96.8 and 93.3 %, respectively. Other members of the family Cyclobacteriaceae had sequence similarities of <92.0 %. However, DNA-DNA hybridization with Cyclobacterium amurskyense KCTC 12363(T) and Cyclobacterium marinum DSM 745(T) showed relatedness values of only 24.5 and 32.5 % with respect to strain M12-11B(T). Based on the results of DNA-DNA hybridization experiments and phenotypic and chemotaxonomic data, it appears that strain M12-11B(T) represents a novel species of the genus Cyclobacterium, for which the name Cyclobacterium qasimii sp. nov. is proposed; the type strain is M12-11B(T) (= KCTC 23011(T) = NBRC 106168(T)) and it has a DNA G+C content of 40.5 mol%.