Sulfide Metabolism and Toxicity in Chlorobaculum Tepidum

温绿杆菌的硫化物代谢和毒性

• 批准号: 0919682
• 负责人: Thomas Hanson
• 金额: $ 65.09万
• 依托单位: University of Delaware
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-08-15 至 2012-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0919682&HistoricalAwards=false
• 关键词: Sulfide; Metabolism; Toxicity; Chlorobaculum; Tepidum

Hydrogen sulfide, the most reduced species of sulfur known, is an important intermediate in the global sulfur cycle, and is also both a potent toxin to and signaling molecule for humans. The research that will be supported by this grant will increase our understanding of a key enzyme that oxidizes sulfide either as a key part of energy metabolism and for detoxification, sulfide:quinone oxidoreductase (SQR). Genes encoding homologs of SQR are found in organisms from all three domains of life ranging from small genome size bacteria and archaea to humans, but few members of this enzyme family have been studied in molecular detail. This study will utilize a model system, Chlorobaculum tepidum, which is the only organism known to contain three genes that encode SQR homologs. Prelimary data indicate that all three genes are expressed and that two of these genes encode active SQRs while the activity of the third gene product remains cryptic. C. tepidum is an anoxygenic, phototrophic bacterium that utilizes sulfide and other reduced sulfur compounds as electron donors for photosynthesis under anaerobic conditions. Anaerobic sulfur oxidizers like C. tepidum help to maintain low sulfide fluxes from anaerobic environments like sediments and hydrothermal systems thereby helping to maintain the aerobic biosphere. The specific goals of this research are to understand the roles of the C. tepidum SQR homologs in the context of the biology of this organism and help to define specific relationships between sequence and functional diversity in the SQR family. All three of the homologs are from clades of SQR that have not previously been studied in biochemical detail. SQRs from two other strains of green sulfur bacteria that are thought to represent low sulfide and high sulfide adapted ecotypes relative to C. tepidum will also be examined. Broader Impacts. A powerful combination of electrochemical, biochemical, and molecular genetic techniques will be employed in the course of this program that will provide highly interdisciplinary training for the undergraduate and graduate students involved. The laboratory has a very successful history of mentoring undergraduates who present data at national meetings and serve as co-authors on published papers. Plans are also in place to disseminate information to the general public and to K-12 educators through numerous ongoing outreach programs at the University of Delaware. These activities include helping the public construct their own microbial gardens and view samples on a phase contrast microscope and providing materials and experiments for incorporating microbiology into K-12 science curriculum.

硫化氢是已知硫还原程度最高的一种，是全球硫循环的重要中间体，也是人类的一种强效毒素和信号分子。这项研究将得到这笔拨款的支持，将增加我们对一种关键酶的理解，这种酶可以氧化硫化物，作为能量代谢和解毒的关键部分，硫化物：醌氧化还原酶（SQR）。编码SQR同源基因的基因存在于从小基因组大小的细菌和古生菌到人类的所有生物中，但对该酶家族成员的分子细节研究很少。本研究将利用一个模型系统，即黄绿杆菌，它是已知的唯一含有三个编码SQR同源基因的生物。初步数据表明，这三个基因都有表达，其中两个基因编码有活性的SQRs，而第三个基因产物的活性仍然是未知的。C. tepidum是一种无氧光养细菌，在厌氧条件下利用硫化物和其他还原性硫化合物作为电子供体进行光合作用。像C. tepidum这样的厌氧硫氧化剂有助于维持来自沉积物和热液系统等厌氧环境的低硫化物通量，从而有助于维持好氧生物圈。本研究的具体目标是了解C. tepidum SQR同源物在该生物的生物学背景下的作用，并有助于确定SQR家族中序列与功能多样性之间的具体关系。所有这三个同源物都来自SQR的分支，以前没有在生化细节上进行过研究。另外两种被认为是相对于C. tepidum的低硫化物和高硫化物适应生态型的绿硫细菌菌株的sqr也将被检查。更广泛的影响。本课程将采用电化学、生化和分子遗传技术的有力结合，为本科生和研究生提供高度跨学科的培训。该实验室在指导本科生在国家会议上展示数据和作为发表论文的共同作者方面有着非常成功的历史。特拉华大学还计划通过众多正在进行的外展项目向公众和K-12教育工作者传播信息。这些活动包括帮助公众建造他们自己的微生物园，在相差显微镜上观察样品，以及为将微生物学纳入K-12科学课程提供材料和实验。