Molecular and Genetic Controls Regulating Bacterial Arsenite Oxidation

调节细菌亚砷酸盐氧化的分子和遗传控制

• 批准号: 0817170
• 负责人: Timothy McDermott
• 金额: $ 34.04万
• 依托单位: Montana State University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-09-01 至 2012-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0817170&HistoricalAwards=false
• 关键词: Molecular; Genetic; Controls; Regulating; Bacterial

Unacceptable health risks associated with elevated arsenic concentrations in drinking water supplies in the United States and epidemic-level arsenic poisoning in countries worldwide (e.g. Bangladesh) have elevated national and global interest in environmental processes controlling the mobility and fate of arsenic in soil and water. Microbial biochemical transformations of arsenic are critically important to controlling its transport, bioavailability, and toxicity in nature. Bacteria will oxidize arsenite [As(III)] or reduce arsenate [As(V)] for either detoxification purposes or to generate cellular energy. However, understanding of the biochemistry and genetics underlying these transformations is overly simplistic, particularly in terms of how microorganisms sense or oxidize As(III), and thus constrains an ability to understand arsenic behavior in the environment. Current studies indicate that two-component signal transduction and quorum sensing co-regulate the aox genes that encode key regulatory and functional activities essential to As(III) oxidation. The focus of this project is to understand how the expression of the aox genes is controlled by these regulatory systems, with the specific aims being to: i) identify sensor and signal transduction components of the two-component proteins AoxS and AoxR; ii) determine how the As(III) signal is perceived; and iii) identify the quorum sensing metabolite(s) involved. In terms of broader impact, the results of this study should be applicable to the field of environmental health and are projected to be of value for guiding remediation efforts aimed at manipulating microbe-As interactions in certain agricultural, mine reclamation, and municipal water treatment settings. The research will also impact human resource development by providing training opportunities for a Ph.D. student and undergraduate research interns, with the latter targeting Native American students. Furthermore, knowledge generated from this study will be integrated into the undergraduate and graduate courses taught by the PIs, as well as at participant-appropriate levels in education-outreach activities that involve grade school, high school, and scientific-lay adult audiences.

美国饮用水供应中砷浓度升高和世界各国（如孟加拉国）的汞中毒水平导致不可接受的健康风险，提高了国家和全球对控制土壤和水中砷的流动性和归宿的环境过程的兴趣。 砷的微生物生物化学转化对控制其在自然界中的迁移、生物有效性和毒性至关重要。 细菌会氧化亚砷酸盐[As（III）]或还原砷酸盐[As（V）]，以达到解毒目的或产生细胞能量。 然而，对这些转变背后的生物化学和遗传学的理解过于简单化，特别是在微生物如何感知或氧化As（III）方面，从而限制了了解环境中砷行为的能力。 目前的研究表明，双组分信号转导和群体感应共调节的aox基因编码的关键监管和功能活动必不可少的As（III）氧化。 该项目的重点是了解aox基因的表达是如何由这些调控系统控制的，具体目标是：i）识别双组分蛋白质AoxS和AoxR的传感器和信号转导组分; ii）确定As（III）信号如何被感知; iii）识别涉及的群体感应代谢物。 在更广泛的影响方面，本研究的结果应适用于环境健康领域，并预计将有价值的指导补救工作，旨在操纵微生物作为在某些农业，矿山复垦，市政水处理设置的相互作用。 该研究还将通过为博士提供培训机会来影响人力资源开发。学生和本科生研究实习生，后者针对美洲原住民学生。 此外，从这项研究中产生的知识将被整合到由PI教授的本科和研究生课程中，以及在涉及小学，高中和科学外行成人观众的教育推广活动中的参与者适当水平。