Collaborative Research: Determining Functional Correlations Between Geochemical Factors and Microbial Metabolisms in Ultrabasic Serpentinizing Ecosystems

对极端环境的研究，尤其是那些被认为与早期地球上普遍存在的条件相似的极端环境的研究，不仅提供了关于生命如何在当今地球上最恶劣的地方生存的见解，而且还提供了关于生命在很久以前可能是如何做到的，也许是在生命的黎明。这部作品将研究在这样一个极端环境中的生活。这是一个蛇纹岩化的地方，液体从地球上冒出来，pH值很高，氧化还原电位很低，几乎没有有机物可吃，几乎没有氧气或其他东西可呼吸：地球上最具挑战性的环境之一。先前对两种地球化学性质不同的高碱性地下水源的研究揭示了基因组和遗传学上不寻常的生物和微生物分离株，使生理和基因组特征适应蛇形环境。在这里，PI将扩展他们以前的研究，重点关注与该站点发生的地球化学和微生物代谢相互作用相关的问题：例如，1)每个主要的微生物群体/参与者如何科普雪松的严格地球化学，2）这些微生物如何相互作用以维持雪松蛇形环境的分类学稳定群落，以及，3）微生物活动如何潜在地有助于发生地球化学转变？为了回答这些问题，PI将使用几种方法测试一些概念，战略和代谢假设，包括：1）先进的显微镜观察的组合，以可视化每个生物体的定位，2）稳定同位素探测，以识别利用给定碳底物的生物体，3）刺激诱导的元转录组学，以说明基因对特定地球化学化合物的反应（条件），4）获得原位蛋白质谱的元蛋白质组学，和5）在地球上的陆地蛇形化位点中大量观察到的分离菌株的详细代谢能力。这五个策略的成功整合的结果，预计将产生一个功能的地球化学因素和微生物代谢活动之间的相互作用模型在一个相对简单的微生物群落，在极端的环境条件下发挥作用。

The study of extreme environments, especially those that are similar to conditions thought to be prevalent on early Earth, provide insights not only into how life ekes out an existence in the most hostile places on our planet today, but how it might have done so long ago, perhaps at the dawn of life. This work will examine life in such an extreme environment. It is a serpentinization site where liquids emerge from the Earth at very high pH, very low redox potential, with almost no organics to eat, and virtually no oxygen or other things to respire: one of the most challenging environments on Earth.Previous studies of two geochemically-different highly-alkaline groundwater sources revealed genomically and phylogentically unusual organisms and microbial isolates having highly-adapted physiological and genomic features to the serpentinizing environments. Here the PIs will expand their previous studies, focusing on questions related to the geochemical and microbial metabolic interactions occurring at this site: e.g., 1) how do each of the major microbial groups/players cope with the stringent geochemistry of The Cedars, 2) how do these microbes interact with one another to sustain the taxonomically stable communities of The Cedars serpentinizing environments, and, 3) how do the microbial activities potentially contribute to the occurring geochemical transformations? To answer these questions the PIs will test a number of conceptual, strategic and metabolic hypotheses, using several approaches, including: 1) a combination of advanced microscopic observations to visualize the localization of each organism, 2) stable-isotope probing to identify organisms that utilize a given carbon substrate, 3) stimulus-induced metatranscriptomics to illustrate the gene responses to the specific geochemical compounds (conditions), 4) metaproteomics to obtain the in situ protein profiles, and 5) detailed metabolic capabilities of isolated strains that are abundantly observed in terrestrial serpentinizing sites on Earth. Successful integration of results from these five strategies is expected to produce a functional interaction-model between geochemical factors and microbial metabolic activities in a relatively simple microbial community, functioning under extreme environmental conditions.