Leucothrix arctica sp. nov., isolated from Arctic seawater

A Gram-stain-negative, non-motile, oxidase- and catalase-positive, rod-shaped bacterium was isolated from a coastal seawater sample from the Arctic Circle and designated strain IMCC9719 T . On the basis of 16S rRNA gene sequence analysis, it was shown that strain IMCC9719 T belonged to the genus Leucothrix and was closely related to the type strains of Leucothrix pacifica (97.6 % similarity) and Leucothrix mucor (95.1 %), while the strain shared <90.6 % sequence similarity with other bacterial species. The average nucleotide identity and genome-to-genome distance values between strain IMCC9719 T and L. pacifica JCM 18388 T were 71.7 and 16.9 %, respectively. The DNA G+C content of strain IMCC9719 T was 43.5 mol%. Optimum growth of strain IMCC9719 T was observed at 15 °C, at pH 7.5-8.5 and in the presence of 2.0-2.5 % (w/v) NaCl. The major fatty acids were summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c), summed feature 8 (C18 : 1ω6c and/or C18 : 1ω7c) and C16 : 0. Cells of strain IMCC9719 T contained diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, an unidentified polar lipid, an unidentified aminophospholipid and two unidentified phospholipids. The major respiratory quinone was ubiquinone-8 (Q-8). Based on the taxonomic data collected in this study, strain IMCC9719 T represents a novel species of the genus Leucothrix, for which the name Leucothrix arctica sp. nov. is proposed. The type strain is IMCC9719 T (=KACC 18010 T =NBRC 110382 T ).