Laboratory of Microbiology, Department of Biochemistry and Microbiology, Ghent University, Gent, Belgium.
BCCM/LMG Bacteria Collection, Gent, Belgium.
Int J Syst Evol Microbiol. 2014 Apr;64(Pt 4):1210-1217. doi: 10.1099/ijs.0.057794-0. Epub 2014 Jan 9.
Two methanotrophic bacteria, strains R-45377(T) and R-45370, were respectively isolated from a slurry pit of a cow stable and from a denitrification tank of a wastewater treatment plant in Belgium. The strains showed 99.9 % 16S rRNA gene sequence similarity. Cells were Gram-negative, motile rods containing type I methanotroph intracytoplasmic membranes. Colonies and liquid cultures appeared white to pale pink. The pmoA gene encoding particulate methane monooxygenase (pMMO) and the nifH gene encoding nitrogenase were present. Soluble methane monooxygenase (sMMO) activity, the presence of the mmoX gene encoding sMMO and the presence of the pxmA gene encoding a sequence-divergent pMMO were not detected. Methane and methanol were utilized as sole carbon sources. The strains grew optimally at 20 °C (range 15-28 °C) and at pH 6.8-7.3 (range pH 6.3-7.8). The strains grew in media supplemented with up to 1.2 % NaCl. The major cellular fatty acids were C16 : 1ω8c, C16 : 1ω5c, C16 : 1ω7c, C14 : 0, C15 : 0 and C16 : 0 and the DNA G+C content was 47 mol%. 16S rRNA gene- and pmoA-based phylogenetic analyses showed that the isolates cluster among members of the genus Methylomonas within the class Gammaproteobacteria, with pairwise 16S rRNA gene sequence similarities of 97.5 and 97.2 % between R-45377(T) and the closest related type strains, Methylomonas scandinavica SR5(T) and Methylomonas paludis MG30(T), respectively. Based on phenotypic characterization of strains R-45377(T) and R-45370, their low 16S rRNA gene sequence similarities and the formation of a separate phylogenetic lineage compared with existing species of the genus Methylomonas, we propose to classify these strains in a novel species, Methylomonas lenta sp. nov., with R-45377(T) ( = LMG 26260(T) = JCM 19378(T)) as the type strain.
两株甲烷营养菌，菌株 R-45377(T) 和 R-45370，分别从比利时一个牛舍的泥浆坑和一个废水处理厂的反硝化罐中分离得到。这些菌株的 16S rRNA 基因序列相似度为 99.9%。细胞呈革兰氏阴性、能动的杆状，含有 I 型甲烷营养菌的细胞质内膜。菌落和液体培养物呈白色至浅粉色。存在编码颗粒状甲烷单加氧酶 (pMMO) 的 pmoA 基因和编码固氮酶的 nifH 基因。未检测到可溶性甲烷单加氧酶 (sMMO) 活性、编码 sMMO 的 mmoX 基因和编码序列不同的 pMMO 的 pxA 基因的存在。甲烷和甲醇可用作唯一的碳源。这些菌株在 20°C（15-28°C 范围）和 pH 6.8-7.3（pH 6.3-7.8 范围）下生长最佳。这些菌株可在添加高达 1.2%NaCl 的培养基中生长。主要细胞脂肪酸为 C16:1ω8c、C16:1ω5c、C16:1ω7c、C14:0、C15:0 和 C16:0，DNA G+C 含量为 47mol%。基于 16S rRNA 基因和 pmoA 的系统发育分析表明，这些分离株在 γ-变形菌纲的甲基单胞菌属内与甲基单胞菌属的成员聚类，与最接近的参考菌株甲基单胞菌属 scandinavica SR5(T) 和甲基单胞菌属 paludis MG30(T) 之间的 16S rRNA 基因序列相似度分别为 97.5%和 97.2%。基于菌株 R-45377(T) 和 R-45370 的表型特征、它们与甲基单胞菌属现有种之间较低的 16S rRNA 基因序列相似性以及与现有种相比形成的单独系统发育谱系，我们建议将这些菌株分类为一个新种，即迟缓甲基单胞菌 sp. nov.，R-45377(T)（=LMG 26260(T)=JCM 19378(T)）作为模式株。
