Lu Huibin, Xing Peng, Phurbu Dorji, Tang Qian, Wu Qinglong
State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, PR China.
University of Chinese Academy of Sciences, Beijing 100049, PR China.
Int J Syst Evol Microbiol. 2018 Jul;68(7):2220-2225. doi: 10.1099/ijsem.0.002812. Epub 2018 May 11.
A Gram-stain negative, alkaliphilic and halotolerant bacterium, designated CCL18, was isolated from Lake Cuochuolong on the Tibetan Plateau. The strain was aerobic, short rod-shaped, catalase- and oxidase-positive, and motile by means of several polar flagella. Phylogenetic analysis based on 16S rRNA gene sequencing indicated that strain CCL18 belongs to the genus Pelagibacterium, with its two closest neighbours being Pelagibacterium halotolerans B2 (96.6 %, 16S rRNA gene sequence similarity) and Pelagibacterium luteolum 1_C16_27 (96.1 %). The predominant respiratory quinone of strain CCL18 was Q-10, with Q-9 as a minor component. The major fatty acids were C18 : 1ω6c/C18 : 1ω7c (60.4 %), C19 : 0cyclo ω8c (8.1 %) and C18 : 0 (6.8 %). The polar lipids included phosphatidylglycerol, diphosphatidylglycerol, seven kinds of unidentified lipids and three kinds of glycolipids. The DNA G+C content was 60.1 mol%. DNA-DNA hybridization showed 35.2 % relatedness between strain CCL18 and P. halotolerans B2 and 24.6 % relatedness to P. luteolum 1_C16_27. Based on phylogenetic analysis, DNA-DNA hybridization and a range of physiological and biochemical characteristics, strain CCL18 was clearly distinguishable from the other strains of the genus Pelagibacterium. It was evident that strain CCL18 could be classified as a novel species of the genus Pelagibacterium, for which the name Pelagibacterium montanilacus sp. nov. is proposed. The type strain is CCL18 (=CGMCC 1.16231=KCTC 62030).
从青藏高原措错龙湖分离出一株革兰氏染色阴性、嗜碱且耐盐的细菌，命名为CCL18。该菌株为需氧菌，短杆状，过氧化氢酶和氧化酶呈阳性，借助数根极生鞭毛运动。基于16S rRNA基因序列的系统发育分析表明，菌株CCL18属于Pelagibacterium属，与其亲缘关系最近的两个菌株分别是耐盐Pelagibacterium halotolerans B2（16S rRNA基因序列相似性为96.6%）和黄色Pelagibacterium luteolum 1_C16_27（96.1%）。菌株CCL18的主要呼吸醌为Q-10，Q-9为次要成分。主要脂肪酸为C18 : 1ω6c/C18 : 1ω7c（60.4%）、C19 : 0环ω8c（8.1%）和C18 : 0（6.8%）。极性脂质包括磷脂酰甘油、双磷脂酰甘油、七种未鉴定的脂质和三种糖脂。DNA G+C含量为60.1 mol%。DNA-DNA杂交显示菌株CCL18与耐盐Pelagibacterium halotolerans B2的相关性为35.2%，与黄色Pelagibacterium luteolum 1_C16_27的相关性为24.6%。基于系统发育分析、DNA-DNA杂交以及一系列生理生化特征，菌株CCL18与Pelagibacterium属的其他菌株明显不同。显然，菌株CCL18可被归类为Pelagibacterium属的一个新物种，为此提出新名称Pelagibacterium montanilacus sp. nov.。模式菌株为CCL18（=CGMCC 1.16231=KCTC 62030）。
