Neurotoxic products of chloroalkene aeorbic cometabolism

氯烯烃有氧共代谢的神经毒性产物

基本信息

批准号：
6577809
负责人：
Lewis Semprini
金额：
$ 10.08万
依托单位：
OREGON HEALTH & SCIENCE UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2002
资助国家：
美国
起止时间：
2002-04-01 至 2003-03-31
项目状态：
已结题

项目摘要

Accidental spills, leaking underground storage tanks, improper disposal, and landfill leachates are often the sources of chlorinated aliphatic hydrocarbons (CAHs) in groundwater. Trichloroethylene (TCE) is the most frequently found contaminant in sites of the National Priority List, and cis-1, 2-dichloroethylene (c-DCE) and vinyl chloride (VC) are commonly present due to the transformation of higher chlorinated parent compounds. Aerobic co-metabolism is a potential biological process for treatment of CAHs both in situ and ex-situ. Here microorganisms stimulated on a primary electron donor fortuitously degrade the contaminant. The process involves relatively non-specific oxygenase enzymes that subsequently oxygenase enzymes that subsequently result in a one-step transformation of the CAHs. These oxygenase enzymes typically have low half-velocity co-efficients, and, as a result, achieve in low contaminant concentrations upon remediation. Co-metabolic degradation of CAHs, however, is known to produce toxic intermediate compounds. This resulting toxicity is an important process in the selection of the co-metabolite process because of its effect on the degradation kinetics. In addition, these toxic intermediate compounds are of concern because of their potential health of ecological impacts if they remain in the treated aquifer. In the proposed research we will expand the understanding of these toxic metabolic intermediates in relation to their identify, their impact upon CAH degradation. Studies and the mechanisms by which toxicity is exhibited. We will focus on the co- metabolism of VC, 1,1-DE, and c-DCE since less we know less about transformation toxicity for these compounds, compared to TCE, will be performed with pure bacterial cultures grown on ammonia, toluene, and butane, to access how co-metabolic transformation of the selected CAHs will be determined. The resulting toxicity will be assessed based on loss in growth substrate utilization activity. Also oxidized products, such as alcohols and organic acids, and oxygen consumption. The mechanism(s) of co-metabolic toxicity will be evaluated in Task 2 using 14C radiolabeled CAHs coupled with protein assay methods. Products of the co-metabolism will be tracked using 14C measurement methods. The distribution of the CAH intermediates will be determined by protein binding assays using the 14C-labeled CAHs. The effective of active substrate metabolism upon the degree of co-metabolic activity and the ability of cell to recovery from toxic effects will be evaluated in Task 3. In Task 4 the impact of o-metabolic toxicity on the composition of consortium in a mixed culture constructed of three different pure cultures, growing on a single substrate (touene and butane) will be evaluated. The changes in the community will be tracked using molecular methods and protein assay methods.

意外溢出，地下储罐泄漏，处置不当和垃圾填充物通常是地下水中氯化脂肪液（CAH）的来源。三氯乙烯（TCE）是国家优先级列表中最常见的污染物，CIS-1，2-二氯乙烯（C-DCE）和氯化乙烯基（VC）通常是由于更高的氯化父母化合物的转化而存在。有氧合作代谢是对原位和前态治疗CAH的潜在生物学过程。在这里，微生物在原代电子供体上刺激了污染物的污染物。该过程涉及相对非特异性的氧合酶，随后将氧化酶酶随后导致CAHS的一步转化。这些氧合酶通常具有较低的一半速度共同效能，因此，在修复后，在低污染物浓度下实现。然而，已知CAH的合作代谢降解可产生有毒的中间化合物。由于其对降解动力学的影响，因此所产生的毒性是选择合代代谢物过程的重要过程。此外，这些有毒的中间化合物令人关注，因为如果它们保留在经过处理的含水层中，它们的生态影响可能会产生潜在的健康影响。在拟议的研究中，我们将扩展对这些有毒代谢中间体的理解，这些中间体与它们的识别以及它们对CAH降解的影响。研究和表现出毒性的机制。我们将重点关注VC，1,1-DE和C-DCE的代谢，因为与TCE相比，我们对这些化合物的转化毒性的了解较少，将使用在氨，甲苯，甲苯，甲苯，甲苯，甲苯，甲苯，甲苯，甲苯，纯种细菌培养物中进行。和丁烷，将如何确定所选CAH的合作代谢转换。最终的毒性将根据生长基材利用活性的损失进行评估。还氧化的产物，例如醇和有机酸以及消耗氧。合作代谢毒性的机制将在任务2中使用14C放射性标记的CAH和蛋白质测定方法进行评估。合作代谢的产物将使用14C测量方法跟踪。 CAH中间体的分布将通过使用14C标记的CAHS来确定蛋白质结合测定。在任务3中，将评估主动底物代谢对合作代谢活性程度以及细胞从毒性作用中恢复的能力的有效性。将评估由三种不同的纯培养物构建，并在单个底物（Touene和丁烷）上生长。将使用分子方法和蛋白质测定方法跟踪社区的变化。