Diversity and activity of sulfate-reducing prokaryotes in a Kamchatka hot springs

Microbial communities of terrestrial hot springs of the Kamchatka Peninsula were studied using amplification and sequencing of 16S rRNA and dsrAB gene fragments. The results showed the presence of various sulfate-reducing prokaryotes in these habitats. It was found that sulfate-reducing prokaryotes belonging to Deltaproteobacteria (Thermodesulforhabdus, Desulfosoma and other members of the Syntrophobacteraceae family), Nitrospiriae (Thermodesulfovibrio), Firmicutes (Desulfotamaculum, Desulfurispora, Desulfmormobacteria) inhabit in neutrophilic and slightly acidic hot springs, while bacteria of the genus Thermodesulofobium prefer moderate acidic hot springs. In high-temperature acidic hot springs, sulfate reduction is mediated by archaea of the Crenarchaeota phylum, the most likely candidates being chemoorganoheterotrophic strains of the genus Vulcanisaeta.

本研究通过扩增并测序16S核糖体RNA（16S rRNA）与dsrAB基因片段，对堪察加半岛陆地热泉的微生物群落展开了系统研究。研究结果显示，此类热泉生境中存在多种硫酸盐还原原核生物。进一步研究表明，隶属于δ-变形菌纲（Deltaproteobacteria，包含热脱硫杆菌属（Thermodesulforhabdus）、脱硫体属（Desulfosoma）及互营杆菌科（Syntrophobacteraceae）的其他类群）、硝化螺旋菌纲（Nitrospiriae，热脱硫弧菌属（Thermodesulfovibrio））、厚壁菌门（Firmicutes，脱硫塔菌属（Desulfotamaculum）、脱硫孢子菌属（Desulfurispora）、Desulfmormobacteria）的硫酸盐还原原核生物，栖息于嗜中性及弱酸性热泉环境；而热脱硫菌属（Thermodesulofobium）细菌则更偏好中酸性热泉生境。在高温酸性热泉中，硫酸盐还原过程由泉古菌门（Crenarchaeota）古菌介导，最具候选潜力的类群为火山古菌属（Vulcanisaeta）的化能有机异养型菌株。