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

对极端环境的研究，特别是那些被认为与地球早期普遍存在的条件相似的环境，不仅提供了关于生命如何在当今地球上最恶劣的地方勉强生存的见解，也提供了对很久以前，可能是在生命诞生时的情况的洞察。这部作品将考察在这样一个极端环境中的生活。这是一个蛇纹岩化的地方，液体在非常高的pH值、非常低的氧化还原电位下从地球上冒出来，几乎没有有机物质可吃，几乎没有氧气或其他东西可以呼吸：这是地球上最具挑战性的环境之一。以前对两个不同的高碱性地下水来源的研究揭示了在基因组和系统发育上不寻常的生物和微生物分离株具有高度适应蛇纹岩环境的生理和基因组特征。在这里，PIs将扩展他们之前的研究，重点关注与这个地点发生的地球化学和微生物代谢相互作用有关的问题：例如，1)每个主要微生物组/角色如何应对雪松严格的地球化学，2)这些微生物如何相互作用，以维持雪松蛇纹化环境中分类上稳定的群落，以及，3)微生物活动如何潜在地促进发生的地球化学变化？为了回答这些问题，PIs将测试一些概念性、战略性和新陈代谢假说，使用几种方法，包括：1)结合先进的显微镜观察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)刺激诱导的变转录组学以说明对特定地化化合物(条件)的基因反应，4)元蛋白质组学以获得原位蛋白质图谱，以及5)在地球上大量观察到的分离菌株的详细代谢能力。这五项战略成果的成功整合有望在一个相对简单的微生物群落中产生一个地球化学因素与微生物代谢活动之间的功能相互作用模式，在极端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 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.