Sakai Sanae, Takaki Yoshihiro, Miyazaki Masayuki, Ogawara Miyuki, Yanagawa Katsunori, Miyazaki Junichi, Takai Ken
Department of Subsurface Geobiological Analysis and Research (D-SUGAR), Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 2-15 Natsushima-cho, Yokosuka, Kanagawa 237-0061, Japan.
Department of Life and Environmental Engineering, Faculty of Environmental Engineering, The University of Kitakyushu, 1-1 Hibikino, Wakamatsu-ku, Kitakyushu, Fukuoka 808-0135, Japan.
Int J Syst Evol Microbiol. 2019 Apr;69(4):1225-1230. doi: 10.1099/ijsem.0.003297. Epub 2019 Mar 7.
A novel hydrogenotrophic methanogen, strain HHB, was isolated from a deep-sea hydrothermal vent chimney sample collected from Beebe Vent Field at the Mid-Cayman Spreading Center, Caribbean Sea. The cells were non-motile regular to irregular cocci possessing several flagella. The novel isolate grew at 60-80 °C, pH 5.0-7.4 and with 1-4 % of NaCl (w/v). The isolate utilized H2/CO2 as the only substrates for growth and methane production. The results of phylogenetic analyses of both 16S rRNA and mcrA gene sequences and comparative genome analysis indicated that HHB represented a member of the order Methanococcales, and was closely related to the members of the genera Methanothermococcus and Methanotorris. The most closely related species were Methanothermococcus okinawensis IH1 and Methanotorris igneus Kol 5 in comparison of 16S rRNA gene sequences (each with 93 % identity), and Methanotorris formicicus Mc-S-70 in the case of deduced amino acid sequence similarity of mcrA genes (92 % similarity). The ANI and AAI values between HHB and the members of the genera Methanothermococcus and Methanotorris were 69-72 % and 66-70 %, respectively. Although many of the morphological and physiological characteristics were quite similar between HHB and the species of the genera Methanothermococcus and Methanotorris, they were distinguishable by the differences in susceptibility to antibiotics, formate utilization, growth temperature and NaCl ranges. On the basis of these phenotypic, phylogenetic and genomic properties, we propose that strain HHB represents a novel species, of a novel genus, Methanofervidicoccus abyssi gen. nov., sp. nov. The type strain is HHB (=JCM 32161=DSM 105918).
从加勒比海开曼中部扩张中心比贝喷口区采集的深海热液喷口烟囱样本中分离出一种新型的嗜氢产甲烷菌，菌株HHB。细胞为不运动的规则至不规则球菌，有几根鞭毛。该新型分离株在60-80°C、pH 5.0-7.4和1-4%（w/v）NaCl条件下生长。该分离株利用H2/CO2作为生长和产甲烷的唯一底物。16S rRNA和mcrA基因序列的系统发育分析以及比较基因组分析结果表明，HHB代表甲烷球菌目成员，与嗜热甲烷球菌属和火甲烷菌属成员密切相关。在16S rRNA基因序列比较中，最密切相关的物种是冲绳嗜热甲烷球菌IH1和火甲烷菌Kol 5（各有93%的同一性），在mcrA基因推导氨基酸序列相似性方面是甲酸火甲烷菌Mc-S-70（92%相似性）。HHB与嗜热甲烷球菌属和火甲烷菌属成员之间的ANI和AAI值分别为69-72%和66-70%。尽管HHB与嗜热甲烷球菌属和火甲烷菌属物种的许多形态和生理特征非常相似，但它们在对抗生素的敏感性、甲酸盐利用、生长温度和NaCl范围方面的差异可区分开来。基于这些表型、系统发育和基因组特性，我们提议菌株HHB代表一个新属的新物种，深海嗜热甲烷球菌属（Methanofervidicoccus abyssi），新种。模式菌株为HHB（=JCM 32161=DSM 105918）。
