title: Methylothermus subterraneus sp. nov., a moderately thermophilic methanotroph isolated from a terrestrial subsurface hot aquifer.
abstract: A novel methane-oxidizing bacterium, strain HTM55(T), was isolated from subsurface hot aquifer water from a Japanese gold mine. Strain HTM55(T) was a Gram-negative, aerobic, motile, coccoid bacterium with a single polar flagellum and the distinctive intracytoplasmic membrane arrangement of a type I methanotroph. Strain HTM55(T) was a moderately thermophilic, obligate methanotroph that grew on methane and methanol at 37-65 °C (optimum 55-60 °C). The isolate grew at pH 5.2-7.5 (optimum 5.8-6.3) and with 0-1 % NaCl (optimum 0-0.3 %). The ribulose monophosphate pathway was operative for carbon assimilation. The DNA G+C content was 54.4 mol% and the major fatty acids were C(16 : 0) (52.0 %) and C(18 : 1)ω7c (34.8 %). Phylogenetic analysis of the 16S rRNA gene sequence indicated that strain HTM55(T) was closely related to Methylothermus thermalis MYHT(T) (99.2 % 16S rRNA gene sequence similarity), which is within the class Gammaproteobacteria. However, DNA-DNA relatedness between strain HTM55(T) and Methylothermus thermalis MYHT(T) was ≤ 39 %. On the basis of distinct phylogenetic, chemotaxonomic and physiological characteristics, strain HTM55(T) represents a novel species of the genus Methylothermus, for which the name Methylothermus subterraneus sp. nov. is proposed. The type strain is HTM55(T) ( = JCM 13664(T) = DSM 19750(T)).
authors.affiliation: Institute of Biogeosciences, Japan Agency for Marine-Earth Science & Technology (JAMSTEC), 2-15 Natsushima-cho, Yokosuka, 237-0061, Japan.
authors.forename: Hisako
authors.initials: H
authors.lastname: Hirayama
authors.affiliation: Institute for Geo-Resources & Environment, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba, 305-8567, Japan.
authors.forename: Yohey
authors.initials: Y
authors.lastname: Suzuki
authors.affiliation: Institute of Biogeosciences, Japan Agency for Marine-Earth Science & Technology (JAMSTEC), 2-15 Natsushima-cho, Yokosuka, 237-0061, Japan.
authors.forename: Mariko
authors.initials: M
authors.lastname: Abe
authors.affiliation: Institute of Biogeosciences, Japan Agency for Marine-Earth Science & Technology (JAMSTEC), 2-15 Natsushima-cho, Yokosuka, 237-0061, Japan.
authors.forename: Masayuki
authors.initials: M
authors.lastname: Miyazaki
authors.affiliation: Institute of Biogeosciences, Japan Agency for Marine-Earth Science & Technology (JAMSTEC), 2-15 Natsushima-cho, Yokosuka, 237-0061, Japan.
authors.forename: Hiroko
authors.initials: H
authors.lastname: Makita
authors.affiliation: Geomicrobiology Group, Kochi Institute for Core Sample Research, Japan Agency for Marine-Earth Science & Technology (JAMSTEC), Monobe B200, Nankoku, Kochi, 783-8502, Japan.
authors.forename: Fumio
authors.initials: F
authors.lastname: Inagaki
authors.affiliation: Department of Technical Services, Marine Works Japan Ltd, 2-16-32 Kamariyahigashi, Kanazawa-ku, Yokohama, 236-0042, Japan.
authors.forename: Katsuyuki
authors.initials: K
authors.lastname: Uematsu
authors.affiliation: Institute of Biogeosciences, Japan Agency for Marine-Earth Science & Technology (JAMSTEC), 2-15 Natsushima-cho, Yokosuka, 237-0061, Japan.
authors.forename: Ken
authors.initials: K
authors.lastname: Takai
mesh_terms: D001482:Base Composition; D004269:DNA, Bacterial / Q000235:genetics; D005227:Fatty Acids / Q000378:metabolism; D045482:Hot Springs / Q000382:microbiology*; D006358:Hot Temperature; D008697:Methane / Q000378:metabolism*; D000432:Methanol / Q000378:metabolism*; D008772:Methylococcaceae / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism; D008969:Molecular Sequence Data; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics
chemical_list: D004269:DNA, Bacterial; D005227:Fatty Acids; D012336:RNA, Ribosomal, 16S; D008697:Methane; D000432:Methanol