Institute of Biogeosciences, Japan Agency for Marine-Earth Science & Technology (JAMSTEC), 2-15 Natsushima-cho, Yokosuka 237-0061, Japan.
College of Systems Engineering and Science, Shibaura Institute of Technology, 307 Fukasaku, Minuma-ku, Saitama-city, Saitama 337-8570, Japan.
Int J Syst Evol Microbiol. 2013 Mar;63(Pt 3):1073-1082. doi: 10.1099/ijs.0.040568-0. Epub 2012 Jun 15.
Two aerobic methane-oxidizing bacterial strains were isolated from distinct marine environments in Japan. Strains IT-4(T) and T2-1 were Gram-stain-negative, aerobic, motile, plump short rods or oval-shaped bacteria with a single polar flagellum and type I intracytoplasmic membranes. They were obligate methanotrophs that grew only on methane or methanol. Each strain possessed the particulate methane monooxygenase (pMMO). The ribulose monophosphate pathway was operative for carbon assimilation. The strains grew best at 37 °C, and did not grow at 45 °C. NaCl was required for growth within a concentration range of 1-8 % (w/v). The major phospholipid fatty acids were C16 : 0, C16 : 1ω7c, and C16 : 1ω5t. The major isoprenoid quinone was MQ-8. The DNA G+C content was 50.9-51.7 mol%. The 16S rRNA gene sequences of the strains showed 99.4 % similarity to each other, and DNA-DNA hybridization analysis indicated that the strains were representatives of the same species. The 16S rRNA gene sequences were highly similar to some marine environmental sequences (94.0-97.7 % similarity), but did not show similarities more than 94 % with sequences of members of other related genera, such as Methylomicrobium, Methylobacter, Methylomonas and Methylosarcina. Phylogenies based on 16S rRNA gene sequences and deduced partial PmoA sequences, and the physiological and chemotaxonomic characteristics revealed that strains IT-4(T) and T2-1 represent a novel species of a new genus in the family Methylococcaceae, for which the name Methylomarinum vadi gen. nov., sp. nov. is proposed. The type strain is IT-4(T) ( = JCM 13665(T) = DSM 18976(T)).
从日本两个不同的海洋环境中分离到两株好氧甲烷氧化细菌菌株。菌株 IT-4(T) 和 T2-1 革兰氏阴性，好氧，运动，丰满的短杆或椭圆形细菌，具有单个极生鞭毛和 I 型细胞内膜。它们是专性甲烷营养菌，只能在甲烷或甲醇上生长。每个菌株都具有颗粒状甲烷单加氧酶（pMMO）。核酮糖单磷酸途径可用于碳同化。菌株在 37°C 下生长最好，在 45°C 下不生长。生长需要 NaCl，浓度范围为 1-8%（w/v）。主要磷脂脂肪酸为 C16:0、C16:1ω7c 和 C16:1ω5t。主要异戊二烯醌为 MQ-8。DNA G+C 含量为 50.9-51.7mol%。菌株的 16S rRNA 基因序列彼此之间的相似度为 99.4%，DNA-DNA 杂交分析表明，这些菌株是同一物种的代表。16S rRNA 基因序列与一些海洋环境序列高度相似（相似度为 94.0-97.7%），但与其他相关属成员的序列相似度不超过 94%，例如 Methylomicrobium、Methylobacter、Methylomonas 和 Methylosarcina。基于 16S rRNA 基因序列和推导的部分 PmoA 序列的系统发育以及生理和化学分类学特征表明，菌株 IT-4(T) 和 T2-1 代表甲基球菌科的一个新属的新型种，提议将其命名为 Methylomarinum vadi gen. nov.，sp. nov.。模式菌株为 IT-4(T)（=JCM 13665(T)=DSM 18976(T)）。
