Spirochaeta psychrophila sp. nov., a psychrophilic spirochaete isolated from subseafloor sediment, and emended description of the genus Spirochaeta
Miyazaki, Masayuki and Sakai, Sanae and Yamanaka, Yuko and Saito, Yumi and Takai, Ken and Imachi, Hiroyuki,, 64, 2798-2804 (2014),
doi = https://doi.org/10.1099/ijs.0.062463-0,
publicationName = Microbiology Society,
issn = 1466-5026,
abstract= An obligately anaerobic, psychrophilic spirochaete, strain MO-SPC1T, was isolated from a methanogenic microbial community grown in a continuous-flow bioreactor. Originally, this community was obtained from subseafloor sediments off the Shimokita Peninsula of Japan in the north-western Pacific Ocean. The cells were motile, Gram-stain-negative, helical, 0.25–0.55×3.6–15 µm, with a wavelength of approximately 0.5–0.6 µm. Strain MO-SPC1T grew at 0–18 °C (optimally at 15 °C), at pH 6.0–7.5 (optimally at pH 6.8–7.0) and in 20–70 g NaCl l−1 (optimally at 30–40 NaCl l−1). The strain grew chemo-organotrophically with mono-, di- and polysaccharides. The major end products of glucose fermentation were acetate, ethanol, hydrogen and carbon dioxide. The abundant polar lipids of strain MO-SPC1T were diphosphatidylglycerol, phosphatidylglycerol, unknown phospholipids and an unknown lipid. The major cellular fatty acids (>5 % of the total) were C14 : 0, C16 : 0, iso-C13 : 0, iso-C14 : 0, iso-C15 : 0, anteiso-C13 : 0 and anteiso-C15 : 0. To the best of our knowledge, this is the first report of the fatty acids iso-C13 : 0 and anteiso-C13 : 0 from a species of the genus Spirochaeta . Isoprenoid quinones were not found. The G+C content of the genomic DNA was 39.8 mol%. 16S rRNA gene sequence-based phylogenetic analysis showed that strain MO-SPC1T was affiliated with the genus Spirochaeta , and its closest relatives were Spirochaeta isovalerica MA-2T (95.6 % sequence identity) and Spirochaeta litoralis R1T (89.4 %). Based on its phenotypic characteristics and phylogenetic traits, strain MO-SPC1T is placed in a separate taxon at the level of a novel species within the genus Spirochaeta, for which the name Spirochaeta psychrophila sp. nov. is proposed, reflecting its true psychrophilic physiology. The type strain is MO-SPC1T ( = JCM 17280T = DSM 23951T). To our knowledge, this is the first report of an isolate of the phylum Spirochaetes from a deep-sea sedimentary environment, and of an obligately psychrophilic nature.,
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