A mesophilic filamentous anoxygenic phototrophic bacterium, designated M50-1, was isolated from a microbial mat of the Chukhyn Nur soda lake (northeastern Mongolia) with salinity of 5−14 g/L and pH 8.0−9.3. The organism is a strictly anaerobic phototrophic bacterium, which required sulfide for phototrophic growth. The cells formed short undulate trichomes surrounded by a thin sheath and containing gas vesicles. Motility of the trichomes was not observed. The cells contained chlorosomes. The antenna pigments were bacteriochlorophyll d and β- and γ-carotenes. Analysis of the genome assembled from the metagenome of the enrichment culture revealed all the enzymes of the 3-hydroxypropionate bi-cycle for autotrophic CO₂ assimilation. The genome also contained the genes encoding a type IV sulfide:quinone oxidoreductase (sqrX). The organism had no nifHDBK genes, encoding the proteins of the nitrogenase complex responsible for dinitrogen fixation. The DNA G + C content was 58.6%. The values for in silico DNA‒DNA hybridization and average nucleotide identity between M50-1 and a closely related bacterium ‘Ca. Chloroploca asiatica’ B7-9 containing bacteriochlorophyll c were 53.4% and 94.0%, respectively, which corresponds to interspecies differences. Classification of the filamentous anoxygenic phototrophic bacterium M50-1 as a new ‘Ca. Chloroploca’ species was proposed, with the species name ‘Candidatus Chloroploca mongolica’ sp. nov.

中文翻译：

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'Candidatus Chloroploca mongolica' sp. 十一月 一种新的嗜温丝状缺氧光养细菌

从 Chukhyn Nur 苏打湖（蒙古东北部）的微生物垫中分离出一种嗜温丝状无氧光养细菌，命名为 M50-1，盐度为 5-14 g/L，pH 值为 8.0-9.3。该生物体是一种严格厌氧的光养细菌，其光养生长需要硫化物。细胞形成短的波浪状毛状体，被薄鞘包围并含有气泡。未观察到毛状体的运动性。细胞含有染色体。触角色素是细菌叶绿素d和β-和γ-胡萝卜素。从富集培养物的宏基因组组装的基因组分析揭示了自养 CO ₂的 3-羟基丙酸双循环的所有酶同化。该基因组还包含编码 IV 型硫化物：醌氧化还原酶 ( sqrX )的基因。该生物体没有nifHDBK基因，该基因编码负责二氮固定的固氮酶复合物的蛋白质。DNA G+C 含量为 58.6%。M50-1 与一种密切相关的细菌Ca之间的计算机DNA-DNA 杂交和平均核苷酸同一性的值。Chloroploca asiatica' B7-9 的细菌叶绿素c含量分别为 53.4% 和 94.0%，对应于种间差异。将丝状无氧光养细菌 M50-1 分类为新的' Ca . 提出了 Chloroploca' 物种，物种名称为 'Candidatus Chloroploca mongolica' sp. 十一月