Department of Biological Sciences, Tokyo Metropolitan University, 1-1 Minami-Osawa, Hachioji, Tokyo 1920397, Japan.
Department of Biochemistry and Molecular Biology, Eberly College of Science, The Pennsylvania State University, PA 16802, USA.
Int J Syst Evol Microbiol. 2020 Nov;70(11):5701-5710. doi: 10.1099/ijsem.0.004465.
A novel thermophilic phototrophic purple sulphur bacterium was isolated from microbial mats (56 °C) at Nakabusa hot springs, Nagano prefecture, Japan. Cells were motile, rod-shaped, stain Gram-negative and stored sulphur globules intracellularly. Bacteriochlorophyll and carotenoids of the normal spirilloxanthin series were the major pigments. Dense liquid cultures were red in colour. Strain No.7 was able to grow photoautotrophically using sulfide, thiosulfate, sulfite and hydrogen (in the presence of sulfide) as electron donors and bicarbonate as the sole carbon source. Optimum growth occurred under anaerobic conditions in the light at 50 °C (range, 40-56 °C) and pH 7.2 (range, pH 7-8). Major fatty acids were C (46.8 %), C ω7 (19.9 %), C ω7 (21.1 %), C (4.6 %) and C (2.4 %). The polar lipid profile showed phosphatidylglycerol and unidentified aminophospholipids to be the major lipids. The only quinone detected was ubiquinone-8. 16S rRNA gene sequence comparisons indicated that the novel bacterium is only distantly related to with a nucleotide identity of 90.4 %. The phylogenetic analysis supported the high novelty of strain No.7 with a long-branching phylogenetic position within the next to . The genome comprised a circular chromosome of 2.99 Mbp (2 989 870 bp), included no plasmids and had a DNA G+C content of 61.2 mol%. Polyphasic taxonomic analyses of the isolate suggested strain No.7 is a novel genus within the . The proposed genus name of the second truly thermophilic purple sulphur bacterium is gen. nov. with the type species sp. nov. (DSM 110881=JCM 39101).
一种新型嗜热光养紫色硫细菌从日本长野县中巴士温泉的微生物垫（56°C）中分离出来。细胞可运动，呈杆状，革兰氏阴性染色，细胞内储存硫球。细菌叶绿素和类胡萝卜素属于正常的螺旋藻叶黄素系列，是主要色素。密集的液体培养物呈红色。菌株 No.7 能够以硫化物、硫代硫酸盐、亚硫酸盐和氢（在有硫化物的情况下）作为电子供体，以碳酸氢盐作为唯一碳源进行光自养生长。最佳生长条件为在黑暗中 50°C（范围为 40-56°C）和 pH7.2（范围为 pH7-8）下进行厌氧生长。主要脂肪酸为 C（46.8%）、Cω7（19.9%）、Cω7（21.1%）、C（4.6%）和 C（2.4%）。极性脂质谱显示磷脂酰甘油和未鉴定的氨基磷脂是主要脂质。唯一检测到的醌是泛醌-8。16S rRNA 基因序列比较表明，新型细菌与仅有 90.4%的核苷酸同源性。系统发育分析支持菌株 No.7 的高度新颖性，它在 内与 有一个长分支的系统发育位置。基因组由一个 2.99 Mbp（2 989 870 bp）的圆形染色体组成，不包含质粒，DNA G+C 含量为 61.2mol%。对该分离株的多相分类学分析表明，菌株 No.7 是 内一个新属。第二个真正的嗜热紫色硫细菌的属名提议为 属，新种为 sp. nov.（DSM 110881=JCM 39101）。
