Diversity, Vertical Distribution, and Metabolic Activities of Inorganic Sulfur-Cycling Prokaryotes in Lake Fryxell, Antarctica

南极弗里克塞尔湖无机硫循环原核生物的多样性、垂直分布和代谢活动

• 批准号: 0085481
• 负责人: Michael Madigan
• 金额: $ 23.5万
• 依托单位: Southern Illinois University at Carbondale
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-01-01 至 2003-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0085481&HistoricalAwards=false
• 关键词: Diversity; Vertical; Distribution; Metabolic; Activities

Cold environments comprise more than ninety percent of the earth's biosphere yet relatively little is known about the diversity, physiology, phylogeny, and metabolic activities of cold-loving (psychrophilic) microorganisms. This research focuses on bacteria involved in the sulfur. The study is Lake Fryxell, a meromictic lake that contains significant levels of sulfide in the water column. The research will take a polyphasic approach that includes in situ biodiversity studies, isolation and laboratory culture, and molecular analysis of metabolic activity. Each of these objectives will be pursued using a combination of traditional research strategies coupled with novel experimental techniques, the prime objective being to dissect the microbiology and microbial ecology of sulfur-cycling that occurs at 0 degree C in Lake Fryxell. Work will focus on Proteobacteria with the biodiversity studies using metabolic genes rather than ribosomal RNA genes as molecular targets. Targeted genes include pufM, csoS1, and dsr. Isolation and culture of key representatives of each major group of sulfur-cycling prokaryotes will be pursued using a combination of methods, including extincting dilution, high-throughput microtiter plate, and archaeal-targeted enrichments. Molecular measurements of metabolic activity in situ will be combined with these biodiversity and laboratory culture results. Collectively, the results of the proposed research will: (1) reveal for the first time the biodiversity of sulfur-cycling prokaryotes active in an important nutrient cycle at permanently cold temperatures; (2) make available new genetic resources of psychrophilic phototrophs, sulfur chemolithotrophs, and sulfate-reducing bacteria for basic research and for biotechnological exploitation; and (3) reveal the most ecologically significant sulfur-cycling prokaryotes in Lake Fryxell and identify metabolically important organisms that remain to be cultured. In addition to advancing an understanding of the microbial sulfur cycle, the results of the proposed research will positively impact efforts to recognize and culture microbial life outside planet Earth, and should reveal the limits, in terms of low temperature, to which microbial sulfur-cycling can occur on Earth.

寒冷环境占地球生物圈的90%以上，但对嗜冷微生物的多样性、生理学、繁殖和代谢活动知之甚少。 这项研究的重点是与硫有关的细菌。研究对象是弗里克塞尔湖，这是一个在水柱中含有大量硫化物的部分混合湖。该研究将采取多相方法，包括原位生物多样性研究、隔离和实验室培养以及代谢活动的分子分析。 这些目标将采用传统的研究策略与新颖的实验技术相结合，主要目标是剖析弗里克塞尔湖0摄氏度下硫循环的微生物学和微生物生态学。 工作将集中在变形菌，生物多样性研究使用代谢基因，而不是核糖体RNA基因作为分子靶点。靶向基因包括pufM、csoS 1和dsr。硫循环原核生物的每一个主要群体的关键代表的分离和培养将采用一系列方法进行，包括离心稀释、高通量微量滴定板和古细菌靶向富集。 代谢活动的分子测量将与这些生物多样性和实验室培养结果相结合。 总的来说，拟议的研究结果将：（1）首次揭示在长期低温下活跃在重要营养循环中的硫循环原核生物的生物多样性：（2）为基础研究和生物技术开发提供新的嗜冷光养菌、硫化能无机营养菌和硫酸盐还原菌的遗传资源;揭示了弗里克塞尔湖中最具生态意义的硫循环原核生物，并确定了有待培养的重要代谢生物。 除了促进对微生物硫循环的了解外，拟议研究的结果还将对认识和培养地球以外微生物生命的努力产生积极影响，并且应该揭示微生物硫循环在低温方面可能发生的限制地球上。