Molecular ecology of sulphate-reducing bacteria involved in anaerobic degradation of hydrocarbons at marine gas and oil seeps

海洋天然气和石油渗漏是微生物硫酸盐还原的热点，因为天然微生物群落长期供应碳氢化合物。在第一个供资期间，各种三角变形菌脱硫八叠球菌/脱硫球菌（DSS）组的成员已被证明是渗漏沉积物（CARD-FISH）的全球关键参与者，并能够降解丁烷和十二烷（DNA-/RNA-SIP）。在拟议项目的一部分，我们的目标是进一步丰富的关键丁烷和十二烷降解硫酸盐还原菌（SRB）从建立富集文化。通过GeneFISH原位检测甲基烷基琥珀酸合酶基因（masD），将进一步靶向降解正烷烃的微生物群落。另一方面，对海洋渗漏沉积物中大量存在的未培养SRB SEEP-SRB 2进行了多相富集和基因组学研究。此外，将继续对来自其他四个未培养的SRB的单细胞基因组进行测序。比较基因组分析和蛋白质组学的结合将被用来深入了解一个共同的基因库和碳氢化合物降解的新的关键酶的表达。通过显示富集的硫酸盐还原菌的环境相关性和现场定量masD和相应的生物，该项目有助于更好地了解现场碳氢化合物周转和环境对石油泄漏的可能反应。

Marine gas and oil seeps are hot spots of microbial sulphate reduction because of a long term supply of hydrocarbons to natural microbial communities. In the first funding period members of the diverse deltaproteobacterial Desulfosarcina/Desulfococcus (DSS) group have been shown to be global key players in seep sediments (CARD-FISH) and to be capable of butane and dodecane degradation (DNA-/RNA-SIP). In one part of the proposed project we aim to further enrich the key butane- and dodecane-degrading sulphate-reducing bacteria (SRB) from established enrichment cultures. The n-alkane- degrading microbial community will be further targeted by in situ detection of methylalkyl-succinate synthase genes (masD) via GeneFISH. In another part, SEEP-SRB2, a group of uncultured SRB highly abundant in marine seep sediments, will be studied by a polyphasic approach including enrichment attempts and genomics. Additionally, sequencing of single cell genomes from four other uncultivated SRB will be continued. The combination of comparative genome analysis and proteomics will be used to gain insights into a common gene pool and the expression of novel key enzymes for hydrocarbon degradation. By showing the environmental relevance of enriched SRB and by the in situ quantification of masD and corresponding organisms this project contributes to a better understanding of in situ hydrocarbon turnover and a possible response of the environment to oil spills.