Biouptake of Mercury: Speciation and Processes at the Cell Surface

美国国家科学基金会化学部的环境化学科学项目支持西北大学Jean-Francois Gaillard教授的研究，他试图建立控制水生系统中汞(Hg)生物有效性的过程，特别是更好地描述与人造配体的络合反应所起的作用。微生物对汞的生物吸收是甲基汞形成的关键步骤，甲基汞是已知的最有效的神经毒素之一。盖拉德教授将研究当溶液中汞的化学形态受到人为或生物配体的存在控制时，细菌表面过程如何调节这一过程。汞与细胞结合部位的相互作用将使用光谱和显微方法进行研究，而汞生物吸收将使用全细胞生物传感器进行评估。还将用伏安法研究汞在溶液中的络合反应。这项研究的目的是为汞生物吸收提供一个分子视角，并挑战关于配体控制的金属生物吸收的传统观点。燃煤等人类活动导致汞向全球环境的排放加剧，这引起了人们对这种分布在世界各地的污染物的普遍关注。这项拟议的工作与工程应用以及保护人类和生态健康有许多重要的联系。它从根本和实际两个方面评估了汞在人为排放后的命运，并重新定义了汞进入微生物食物网的途径。这项研究计划将培养环境生物无机化学方面的博士和本科生，并与致力于控制环境中汞浓度的行业发展合作。

The Environmental Chemical Sciences Program in the Chemistry Division at the National Science Foundation supports the research of Professor Jean-Francois Gaillard at Northwestern University who seeks to establish the processes that control the bioavailability of Mercury (Hg) in aquatic systems and particularly to better delineate the role played by complexation reactions with human made ligands. Mercury biouptake by microbial species is a key step in the formation of methyl-mercury, one of the most potent neurotoxins known. Professor Gaillard will examine how bacterial surface processes regulate this process when the chemical speciation of Hg in solution is controlled by the presence of either anthropogenic or biogenic ligands. The interactions of Hg with cell binding sites will be investigated using spectroscopic and microscopic methods, whereas Hg biouptake will be assessed using a whole cell biosensor. Hg complexation reactions in solution will also be investigated using voltammetric methods. The goal of this research is to provide a molecular perspective on mercury biouptake as well as challenge conventional views on ligands controlled metal biouptake. The exacerbation of the release of mercury to the global environment as a result of human activities such as coal burning has raised a general concern about this pollutant that is distributed worldwide. The proposed work has many essential connections to engineering applications and the protection of human and ecological health. It evaluates in both fundamental and practical ways the fate of Hg in response to anthropogenic releases and redefines Hg entry pathways into microbial foodwebs. This research program will train a Ph.D. and undergraduate students in environmental bioinorganic chemistry and develop collaborations with the industry that is working to control Hg concentrations in the environment.