Geochemical Controls on the Adsorption, Bioavailability

对吸附、生物利用度的地球化学控制

• 批准号: 7064109
• 负责人: Stephen A. Boyd
• 金额: $ 34.49万
• 依托单位: MICHIGAN STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-04-01 至 2011-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7064109
• 关键词: Burkholderia; Nocardiaceae; Raman spectrometry; X ray crystallography; adsorption; aromatic hydrocarbon receptor; bacterial genetics; benzofurans; biosensor device; biotransformation; carbopolycyclic compound; clay; computer simulation; confocal scanning microscopy; dioxins; environmental toxicology; flow cytometry; green fluorescent proteins; halobiphenyl /halotriphenyl compound; hydropathy; microarray technology; molecular biology; nuclear magnetic resonance spectroscopy

Our objectives are to characterize poorly understood mechanistic processes that control sorption of Ahreceptor ligands (AhRLs) to mineral surfaces, and then use these well-defined systems to probe the bioavailability of sorbed AhRLs to bacteria and mammals. Since AhRLs tend to have exceptionally low water solubilities, these highly toxic compounds exist in the environment predominantly as sorbed species. We argue that clay minerals are a major, largely unrecognized sink for AhRLs in the environment. Our preliminary studies and the literature suggest that clays may play a nearly equal or even dominant role to that of organic matter in the immobilization of dioxins in soils. Our proposal has four specific aims: 1) To measure sorption and sequestration of key AhRLs to clay minerals and to characterize the geochemical controls on that sorption, 2) To determine the molecular mechanisms of such sorption through integrating bulk results with spectroscopy and molecular simulation studies, thereby promoting more rational long-term Superfund site stewardship, 3) To identify microbial genetic and functional responses to minerals themselves and to mineral-adsorbed AhRLs in order to elucidate key mechanisms of microbial interaction with these adsorbed compounds, and 4) To quantify the microbial functionality enabling bioavailability and biodegradation of mineral-sorbed AhRLs by using fluorescent markers that are expressed with key microbial responses. Thus our proposal supports the mission of the Superfund Basic Research and Training Program because in Objective 1 we will work to "identify and quantify chemical forms of the contaminants," in Objectives 1-2 we will assess "the physical, chemical and biological processes affecting chemicals in environmental media," and in Objectives 3-4 we will link this work directly to bioavailability of Superfund chemicals to bacteria and to mammals. Relevance of this research to public health: Many toxic organic contaminants are so insoluble in water that the main route of human exposure is through ingestion of adsorbed contaminants. We propose to characterize adsorption of dioxins and related compounds to clay minerals, and then use both bulk and molecular methods to understand the effects of adsorption on the toxicity of the compound (to mice) and the biodegradation of the compound (by soil bacteria), which is needed in remediation and risk assessment.

我们的目标是描述控制 Ahreceptor 吸附的鲜为人知的机械过程 配体（AhRL）到矿物表面，然后使用这些明确的系统来探测 吸附的 AhRL 对细菌和哺乳动物的生物利用度。由于 AhRL 的水份往往特别低 由于溶解度较高，这些剧毒化合物主要以吸附物质的形式存在于环境中。我们 认为粘土矿物是环境中 AhRL 的一个主要的、基本上未被认识到的汇。我们的 初步研究和文献表明粘土可能起着几乎同等甚至主导的作用 有机物在土壤中固定二恶英的作用。我们的提案有四个具体目标： 1) 测量关键 AhRL 对粘土矿物的吸附和封存，并表征地球化学特征 控制该吸附，2）通过积分确定这种吸附的分子机制 通过光谱学和分子模拟研究获得批量结果，从而促进更合理的长期 超级基金场地管理，3) 识别微生物对矿物质本身的遗传和功能反应 以及矿物质吸附的 AhRL，以阐明微生物与这些物质相互作用的关键机制 吸附的化合物，以及 4) 量化微生物功能，从而实现生物利用度和 使用关键微生物表达的荧光标记对矿物质吸附的 AhRL 进行生物降解 回应。因此，我们的提案支持超级基金基础研究和培训计划的使命 因为在目标 1 中，我们将致力于“识别和量化污染物的化学形式”， 目标 1-2 我们将评估“影响化学品的物理、化学和生物过程 环境介质”，在目标 3-4 中，我们将这项工作直接与超级基金的生物利用度联系起来 化学物质对细菌和哺乳动物的影响。这项研究与公共卫生的相关性：许多有毒有机污染物非常难溶于水，因此人类接触污染物的主要途径是摄入吸附的污染物。我们建议表征二恶英和相关化合物对粘土矿物的吸附，然后使用散装和 分子方法来了解吸附对化合物毒性（对小鼠）的影响以及 化合物的生物降解（通过土壤细菌），这是修复和风险评估所需的。