Subsurface Geobiology Advanced Research (SUGAR) Project, Extremobiosphere Research Program, Institute of Biogeosciences, Japan Agency for Marine-Earth Science & Technology (JAMSTEC), Yokosuka, Kanagawa 237-0061, Japan.
Department of Environmental Systems Engineering, Nagaoka University of Technology, Nagaoka, Niigata 940-2188, Japan.
Int J Syst Evol Microbiol. 2012 Jun;62(Pt 6):1389-1395. doi: 10.1099/ijs.0.035048-0. Epub 2011 Aug 12.
A novel mesophilic, hydrogenotrophic methanogen, designated strain TNR(T), was isolated from an anaerobic, propionate-degradation enrichment culture that was originally established from a rice field soil sample from Taiwan. Cells were non-motile rods, 2.0-6.5 µm long by 0.3 µm wide. Filamentous (up to about 100 µm) and coccoid (about 1 µm in diameter) cells were also observed in cultures in the late exponential phase of growth. Strain TNR(T) grew at 20-40 °C (optimally at 37 °C), at pH 6.5-7.4 (optimally at pH 7.0) and in the presence of 0-25 g NaCl l(-1) (optimally at 0 g NaCl l(-1)). The strain utilized H(2)/CO(2) and formate for growth and produced methane. The G+C content of the genomic DNA was 56.4 mol%. Based on sequences of both the 16S rRNA gene and the methanogen-specific marker gene mcrA, strain TNR(T) was related most closely to Methanolinea tarda NOBI-1(T); levels of sequence similarities were 94.8 and 86.4 %, respectively. The 16S rRNA gene sequence similarity indicates that strain TNR(T) and M. tarda NOBI-1(T) represent different species within the same genus. This is supported by shared phenotypic properties, including substrate usage and cell morphology, and differences in growth temperature. Based on these genetic and phenotypic properties, strain TNR(T) is considered to represent a novel species of the genus Methanolinea, for which the name Methanolinea mesophila sp. nov. is proposed; the type strain is TNR(T) ( = NBRC 105659(T) = DSM 23604(T)). In addition, we also suggest family status for the E1/E2 group within the order Methanomicrobiales, for which the name Methanoregulaceae fam. nov. is proposed; the type genus of family is Methanoregula.
一株新型嗜中温、氢营养型产甲烷古菌，被命名为 TNR(T) 菌株，它是从一个来自台湾稻田土壤样本的厌氧、丙酸降解富集培养物中分离出来的。细胞是无动力的杆状，长 2.0-6.5 µm，宽 0.3 µm。在生长的指数晚期培养物中，也观察到丝状（长达约 100 µm）和球形（直径约 1 µm）细胞。TNR(T) 菌株在 20-40°C（最佳温度为 37°C）、pH6.5-7.4（最佳 pH 值为 7.0）和 0-25 g NaCl l(-1)（最佳为 0 g NaCl l(-1)）的条件下生长。该菌株利用 H(2)/CO(2)和甲酸盐进行生长并产生甲烷。基因组 DNA 的 G+C 含量为 56.4 mol%。基于 16S rRNA 基因和产甲烷菌特异性标记基因 mcrA 的序列，TNR(T) 菌株与 Methanolinea tarda NOBI-1(T)最为密切相关；序列相似性分别为 94.8%和 86.4%。16S rRNA 基因序列相似性表明，TNR(T) 菌株和 M. tarda NOBI-1(T)代表同一属中的不同种。这得到了表型特性的支持，包括底物利用和细胞形态，以及生长温度的差异。基于这些遗传和表型特性，TNR(T) 菌株被认为代表 Methanolinea 属的一个新型种，建议将其命名为嗜中温产甲烷菌 Methanolinea mesophila sp. nov.；其模式菌株为 TNR(T)（=NBRC 105659(T)=DSM 23604(T)）。此外，我们还建议将 Methanomicrobiales 目内的 E1/E2 组提升为科地位，建议将其命名为 Methanoregulaceae 科；该科的模式属为 Methanoregula。
