S(0) Globule Metabolism in Chlorobaculum tepidum: Interdisciplinary Studies of a Novel Microbe Mineral Interaction

单质硫（S(0)）是一种常见的化学物质，广泛参与环境和工业反应。S(0)是一种无毒、相对惰性、在大多数条件下不流动的固体。它是黄石国家公园的“黄色”，在农业中被用作缓释肥料，也是工业过程中从废物中去除有毒硫化氢的理想最终产品。S(0)的循环是由微生物活动驱动的。从广义上讲，该项目旨在通过解决以下问题为微生物-矿物相互作用提供新的见解：单个微生物如何合成和降解不溶性无机化合物？本工程的模型系统为光养绿硫菌温绿杆菌（Chlorobaculum tepidum）。虽然一些微生物形成或消耗细胞外矿物质，但Cba。二氢化物是不寻常的，因为它既从硫化氢形成S(0)，又在硫化氢不存在的情况下消耗S(0)。纳米尺度成像、分析化学和分子生物学的工具将被应用于确定Cba如何。温虫草在形成和消耗过程中与S(0)相互作用。该项目旨在确定S(0)形成和消耗所需的特定基因产物。然后，它将讨论这些基因产物如何定制Cba。温片和S(0)表面的生产相互作用。能量和养分的可用性是确定微生物生态位和微生物群落在给定环境中成功的关键参数。绝大多数培养的微生物从可溶于水介质的化合物中获得能量和营养。然而，许多资源以不溶性矿物的形式结合，如S(0)。本项目对细胞与不溶性矿物质相互作用机制的理解将为其他微生物-矿物质系统（即铁/锰氧化和还原细菌）提供指导性比较，并使我们能够区分独特和普遍的特征。更广泛的影响微生物-矿物相互作用的研究提供了一个极好的机会，培养学生和初级科学家在化学，生物学和环境科学的界面。本项目将在项目期间为至少2名博士生、1名博士后和3名本科生提供跨学科培训。这包括细菌分子遗传学、“组学”技术、厌氧培养、纳米级成像和元素分析技术方面的技术培训。PI作为与当地少数民族服务机构建立本科到研究生衔接项目的IGERT （DGE-1144726）的共同PI，将促进代表性不足群体的参与。该项目产生的结果和信息将通过每年吸引10,000名游客的特拉华大学海岸日、终身学习研讨会、科学研讨会和公众团体参观特拉华生物技术研究所向公众传播。这些公共互动的目标是传授环境微生物作为有益的生物地球化学引擎的关键作用，而不仅仅是疾病的代理人。PI和共同PI将专门针对K-12教育工作者参加“服务日”培训研讨会。

Intellectual MeritElemental sulfur, S(0), is a common chemical species involved in a wide range of environmental and industrial reactions. S(0) is a non-toxic, relatively inert, immobile solid under most conditions. It is the "Yellow" in Yellowstone National Park, it is applied as a slow release fertilizer in agriculture, and it is the desired end product for industrial processes that remove toxic hydrogen sulfide from waste. The cycling of S(0) is driven by microbial activity. Broadly this project seeks to provide new insights into microbe-mineral interactions by addressing the following question:How does a single microbe both synthesize and degrade an insoluble inorganic compound? The model system for this project is the phototrophic green sulfur bacterium Chlorobaculum tepidum. While some microbes either form or consume extracellular minerals, Cba. tepidum is unusual as it both forms S(0) from hydrogen sulfide and consumes S(0) when hydrogen sulfide is not present. Tools of nanoscale imaging, analytical chemistry and molecular biology will be applied to identify how Cba. tepidum interacts with S(0) during its formation and consumption. The project seeks to identify specific gene products required for both S(0) formation and consumption. It will then address how these gene products tailor both Cba. tepidum and S(0) surfaces for productive interaction. The availability of energy and nutrients are critical parameters that define microbial niches and the success of microbial communities in a given environment. The vast majority of cultured microbes obtain energy and nutrients from compounds soluble in aqueous media. However, many resources are bound as insoluble minerals, like S(0). The understanding of mechanisms for cellular interactions with insoluble minerals developed in this project will provide an instructive comparison to other microbe-mineral systems (i.e. Fe/Mn oxidizing and reducing bacteria) and allow us to discriminate between unique and universal features. Broader ImpactsThe study of microbe-mineral interactions provides an excellent opportunity to train students and junior scientists at the interface of chemistry, biology, and environmental science. The project will provide interdisciplinary training for at least two Ph.D. students, one postdoctoral scholar and three undergraduates over the duration of the project. This includes technical training in bacterial molecular genetics, "omics" techniques, anaerobic culturing, and nanoscale imaging and elemental analysis techniques. The participation of under-represented groups will be facilitated by the PI's role as a Co-PI on an IGERT (DGE-1144726) that is establishing undergraduate-to-graduate bridge programs with local minority serving institutions. Results and information generated by this project will be disseminated to the public through the University of Delaware's Coast Day, which attracts 10,000 visitors each year, lifelong learning seminars, science cafés, and public group visits to the Delaware Biotechnology Institute. The goal of these public interactions is to impart the critical role of environmental microbes as beneficial biogeochemical engines and not solely agents of disease. K-12 educators will specifically be targeted by PI and Co-PI participation in "in service day" training seminars.