S. N. Winogradsky Institute of Microbiology, Russian Academy of Sciences, Moscow 117312, Russia.
Netherlands Institute of Ecology (NIOO-KNAW), PO Box 50, 6700AB Wageningen, The Netherlands.
Int J Syst Evol Microbiol. 2013 Mar;63(Pt 3):1096-1104. doi: 10.1099/ijs.0.043505-0. Epub 2012 Jun 15.
A novel species is proposed for two facultatively methanotrophic representatives of the genus Methylocystis, strains H2s(T) and S284, which were isolated from an acidic (pH 4.3) Sphagnum peat-bog lake (Teufelssee, Germany) and an acidic (pH 3.8) peat bog (European North Russia), respectively. Cells of strains H2s(T) and S284 are aerobic, Gram-negative, non-motile, curved coccoids or short rods that contain an intracytoplasmic membrane system typical of type-II methanotrophs. They possess both a soluble and a particulate methane monooxygenase (MMO); the latter is represented by two isozymes, pMMO1 and pMMO2. The preferred growth substrates are methane and methanol. In the absence of C1 substrates, however, these methanotrophs are capable of slow growth on acetate. Atmospheric nitrogen is fixed by means of an aerotolerant nitrogenase. Strains H2s(T) and S284 grow between pH 4.2 and 7.6 (optimum pH 6.0-6.5) and at 8-37 °C (optimum 25-30 °C). The major fatty acids are C18 : 1ω8c, C18 : 1ω7c and C16 : 1ω7c; the major quinone is Q-8. The DNA G+C content is 62.0-62.3 mol%. Strains H2s(T) and S284 share identical 16S rRNA gene sequences, which displayed 96.6-97.3 % similarity to sequences of other taxonomically characterized members of the genus Methylocystis. Therefore, strains H2s(T) and S284 are classified as members of a novel species, for which the name Methylocystis bryophila sp. nov. is proposed; strain H2s(T) ( = DSM 21852(T) = VKM B-2545(T)) is the type strain.
提出了一个新的种，用于两个兼性甲烷氧化菌属甲基球菌的代表菌株 H2s(T)和 S284，它们分别从酸性（pH 4.3）的泥炭沼泽湖（德国的魔鬼湖）和酸性（pH 3.8）的泥炭沼泽（俄罗斯欧洲北部）中分离出来。菌株 H2s(T)和 S284 的细胞是需氧的，革兰氏阴性，非运动性的，弯曲的球菌或短杆菌，含有典型的 II 型甲烷氧化菌的细胞内膜系统。它们都有可溶性和颗粒状甲烷单加氧酶（MMO）；后者由两个同工酶，pMMO1 和 pMMO2 组成。首选的生长底物是甲烷和甲醇。然而，在没有 C1 底物的情况下，这些甲烷氧化菌能够在乙酸盐上缓慢生长。大气氮通过耐氧氮酶固定。菌株 H2s(T)和 S284 在 pH 值 4.2 到 7.6 之间（最佳 pH 值为 6.0-6.5）和 8-37°C（最佳温度为 25-30°C）生长。主要脂肪酸是 C18 : 1ω8c、C18 : 1ω7c 和 C16 : 1ω7c；主要醌是 Q-8。DNA G+C 含量为 62.0-62.3 mol%。菌株 H2s(T)和 S284 的 16S rRNA 基因序列完全相同，与其他分类学上已鉴定的甲基球菌属成员的序列相似度为 96.6-97.3%。因此，菌株 H2s(T)和 S284 被分类为一个新种的成员，建议将其命名为 Methylocystis bryophila sp. nov.；菌株 H2s(T)（=DSM 21852(T)=VKM B-2545(T)）是模式菌株。
