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

洋中脊的热液喷口是独特的，在主要食物有限的深海中高产的环境。为了更全面地了解热液沉积物初级生产者的遗传能力，提出了宏基因组分析。重点将放在Logatchev热液喷口区域典型的白色覆盖沉积物的上层，在28厘米深度显示高达100°C。基于我们的多样性研究结果，我们已经建立了宏基因组化石文库并将进行分析。我们将重点关注携带编码甲烷和硫化物氧化关键蛋白基因的宏基因组克隆。生物信息学工具将用于将宏基因组片段与确定的物种或系统发育群联系起来。该研究将由fosmid插入端测序补充，以获得更广泛的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。结果将与人工栽培和其他不依赖于人工栽培的方法得到的结果进行比较，并与地质和流体地球化学数据进行对比。对这些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，以及能量和物质从地幔向海洋的转移。

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.