Research Center of Biotechnology of the Russian Academy of Sciences, Leninsky ave. 33, bld. 2, Moscow 119071, Russian Federation.
Institute of Basic Biological Problems of Russian Academy of Sciences, Federal Research Center "Pushchino Scientific Center for Biological Research of Russian Academy of Sciences", Institutskaya ave. 2, Pushchino 142290, Russian Federation.
FEMS Microbiol Lett. 2019 Mar 1;366(5). doi: 10.1093/femsle/fnz043.
In this article, we present the description of a novel mesophilic phototrophic Chloroflexi bacterium, 'Candidatus Viridilinea mediisalina' Kir15-3F. We have isolated an anaerobic, highly enriched culture of this bacterium from the Kiran soda lake (Siberia) and optimized its cultivation. Metagenomic sequencing revealed that 'Ca. Viridilinea mediisalina' Kir15-3F is a bacteriochlorophyll-containing Chloroflexi bacterium in the enrichment culture. Fluorescent in situ hybridisation demonstrated a link between the phenotype described here and the 'Ca. Viridilinea mediisalina' Kir15-3F genome. Spectrophotometry and high-performance liquid chromatography analyses showed the presence of bacteriochlorophylls d, c and a, as well as lycopene, γ-carotene and β-carotene. Transmission electron microscopy showed chlorosomes, gas vesicles, polyhydroxyalkanoate-like and polyphosphate-like granules. Our results illustrated that 'Ca. Viridilinea mediisalina' Kir15-3F is an alkaliphilic, salt-tolerant, obligately mesophilic, anaerobic, phototrophic bacterium. The genome sequences lack genes of the Calvin cycle and a sulphide:quinone reductase gene for sulphide oxidation. Owing to the lack of an axenic culture and based on the genomic and phenotypic data, we have presented the description of the bacterium in the Candidatus category.
本文介绍了一种新型嗜中温光养绿弯菌（Chloroflexi bacterium），暂命名为“Candidatus Viridilinea mediisalina”Kir15-3F。我们从基兰苏打湖（西伯利亚）中分离到一株该菌的厌氧、高度富集培养物，并对其进行了优化培养。宏基因组测序表明，富集培养物中的“Ca. Viridilinea mediisalina”Kir15-3F 是一种含细菌叶绿素的绿弯菌。荧光原位杂交技术证明了这里描述的表型与“Ca. Viridilinea mediisalina”Kir15-3F 基因组之间存在联系。分光光度法和高效液相色谱分析表明存在细菌叶绿素 d、c 和 a 以及番茄红素、γ-胡萝卜素和β-胡萝卜素。透射电子显微镜显示存在菌绿体、气囊、聚羟基烷酸样和多磷酸盐样颗粒。我们的研究结果表明，“Ca. Viridilinea mediisalina”Kir15-3F 是一种嗜碱性、耐盐、严格中温、厌氧、光养细菌。基因组序列缺乏卡尔文循环和用于硫化物氧化的硫代醌还原酶基因。由于缺乏无菌培养物，并且基于基因组和表型数据，我们将该细菌暂归类为“Candidatus”。
