Metagenomic studies of the diversity and function of chemosynthetic microbial communities at oceanic spreading zones

大洋中脊的热液喷口是主要食物有限的深海中独特的、高产的环境。为了更全面地了解热液沉积物中初级生产者的成因能力，提出了元基因组分析。重点将放在洛加切夫热液喷口地区典型的白色覆盖的沉积物的上层，深度可达100°C，深度达28厘米。根据我们的多样性研究结果，我们已经构建了元基因组融合体库，并将对其进行分析。我们将重点研究携带甲烷和硫化物氧化关键蛋白编码基因的元基因组克隆。生物信息学工具将用于将元基因组片段与已定义的物种或系统发育组联系起来。这项研究将得到Fosid插入末端测序的补充，以更广泛地获得微生物群落的遗传能力。信使RNA表达分析将用于评估特定基因是否表达。结果将与栽培和其他与栽培无关的方法获得的结果进行比较，并与地质和流体地球化学数据相关联。对数据的联合分析将有助于更详细地了解热液喷口的生物地球化学过程，以及从地幔到海洋的能量和物质转移。

Hydrothermal vents at mid-ocean ridges are unique, highly productive environments amidst the predominantly food-limited deep-sea. To obtain a more comprehensive understanding of the genetic capabilities of primary producers in hydrothermal sediments, metagenome analysis is proposed. The focus will be set on the upper layers of typically white-covered sediments, exhibiting up to 100°C in 28 cm depth, in the Logatchev hydrothermal vent area. Based on results of our diversity studies, metagenomic fosmid libraries have been constructed and will be analysed. We will focus on metagenomic clones carrying genes encoding key proteins of methane and sulfide oxidation. Bioinformatic tools will be used to link metagenomic fragments to defined species or phylogenetic groups. The study will be complemented by fosmid insert-end sequencing, to get a broader access to the genetic capabilities of the microbial communities. Messenger RNA expression analysis will serve to evaluate whether specific genes are expressed or not. The results will be compared with results obtained by cultivation and other cultivation-independent methods and correlated to geological and fluid geochemical data. The joint analysis of the data will lead to a more detailed understanding of biogeochemical processes at hydrothermal vents, and of the transfer of energy and material from mantle to ocean.