Kaluzhnaya M, Khmelenina V, Eshinimaev B, Suzina N, Nikitin D, Solonin A, Lin J L, McDonald I, Murrell C, Trotsenko Y
G.K.Skryabin Institute of Biochemistry and Physiology of Microorganisms RAS, Pushchino, Moscow, Russia.
Syst Appl Microbiol. 2001 Jul;24(2):166-76. doi: 10.1078/0723-2020-00028.
Five strains of obligate methanotrophic bacteria (4G, 5G, 6G, 7G and 5B) isolated from bottom sediments of Southeastern Transbaikal soda lakes (pH 9.5-10.5) are taxonomically described. These bacteria are aerobic, Gram-negative monotrichous rods having tightly packed cup-shaped structures on the outer cell wall surface (S-layers) and Type I intracytoplasmic membranes. All the isolates possess particulate methane monooxygenase (pMMO) and one strain (5G) also contains soluble methane monooxygenase (sMMO). They assimilate methane and methanol via the ribulose monophosphate pathway (RuMP). The isolates are alkalitolerant or facultatively alkaliphilic, able to grow at pH 10.5-11.0 and optimally at pH 8.5-9.5. These organisms are obligately dependent on the presence of sodium ions in the growth medium and tolerate up to 0.9-1.4 M NaCl or 1 M NaHCO3. Although being mesophilic, all the isolates are resistant to heating (80 degrees C, 20 min), freezing and drying. Their cellular fatty acids profiles primarily consist of C(16:1). The major phospholipids are phosphatidylethanolamine and phosphatidylglycerol. The main quinone is Q-8. The DNA G+C content ranges from 49.2-51.5 mol %. Comparative 16S rDNA sequencing showed that the newly isolated methanotrophs are related to membres of the Methylomicrobium genus. However, they differ from the known members of this genus by DNA-DNA relatedness. Based on pheno- and genotypic characteristics, we propose a new species of the genus Methylomicrobium Methylomicrobium buryatense sp. nov.
对从外贝加尔东南部苏打湖底部沉积物（pH 9.5 - 10.5）中分离出的五株专性甲烷氧化细菌（4G、5G、6G、7G和5B）进行了分类学描述。这些细菌为需氧菌，革兰氏阴性，单端鞭毛杆菌，在外细胞壁表面（S层）具有紧密堆积的杯状结构和I型胞内膜。所有分离株都具有颗粒性甲烷单加氧酶（pMMO），其中一株（5G）还含有可溶性甲烷单加氧酶（sMMO）。它们通过磷酸核酮糖途径（RuMP）同化甲烷和甲醇。这些分离株具有耐碱性或兼性嗜碱性，能够在pH 10.5 - 11.0下生长，最适生长pH为8.5 - 9.5。这些微生物绝对依赖生长培养基中钠离子的存在，能耐受高达0.9 - 1.4 M NaCl或1 M NaHCO₃。尽管为嗜温菌，但所有分离株都耐热（80℃，20分钟）、耐冷冻和干燥。它们的细胞脂肪酸谱主要由C(16:1)组成。主要的磷脂是磷脂酰乙醇胺和磷脂酰甘油。主要醌为Q - 8。DNA G + C含量范围为49.2 - 51.5 mol%。比较16S rDNA测序表明，新分离的甲烷氧化菌与甲基微菌属的成员有关。然而，它们与该属已知成员在DNA - DNA相关性方面存在差异。基于表型和基因型特征，我们提出了甲基微菌属的一个新物种——布里亚特甲基微菌（Methylomicrobium buryatense sp. nov.）。
