Microbial Degradation of Agent Orange

各种化学物质以除草剂/杀虫剂、脱脂剂、阻燃剂、工业溶剂或化学工业副产品的形式释放到我们的环境中，导致了严重的环境污染问题。美国国会特别授权超级基金清理美国数以千计的有毒物质倾倒场，但清理的很少。微生物负责回收天然废物，但它们对合成化合物相对迟钝，特别是自然环境中很少出现的高氯化化合物。然而，微生物具有很强的适应性，并且已经进化并不断进化出结构和调控基因，这些基因指定了各种简单氯化化合物的生物降解。因此，微生物修复高氯化化合物是解决有毒化学污染问题的主要目标。为了加快有毒合成化学品的微生物生物降解速度，人们需要了解结构基因调控的性质，以及这些调控基因的作用机制和进化。然而，即使微生物可以有效地降解和去除有毒化学物质，除非确定其对当地人口的致病潜力，否则也不一定用于生物修复。这项提议有两个主要目标。第一个了解简单的以及有些顽固的氯化化合物在自然界中是如何进化的降解途径的。我们对生物降解途径中调控结构基因表达水平的调控基因的进化和作用模式特别感兴趣。我们的第二个目标是发展概念和技术上的理解和方法，以评估生物修复有机体的致病潜力。已取得的进展和我们打算实现我们的目标的方式在这项提案中有详细说明

Various chemicals are released in our environment as herbicides/pesticides, degreasers, fire retardants, industrial solvents o as by-products of chemical industry, leading to major environmental pollution problem. The U.S. Congress specifically authorized the Super Funds to clean up thousands of toxic dump sites in the United States, but very few have been cleaned up. Microorganisms are responsible for recycling natural wastes, but they are relatively inert towards synthetic compounds, particularly the high chlorinated compounds that occur rarely in the natural environment. Yet, microorganisms are highly adaptable and have evolved, and are continually evolving, the genes, both structural and regulatory, that specify biodegradation of a variety of simple chlorinated compounds. Microbial remediation of highly chlorinated compounds is thus a major goal to address problems of toxic chemical pollution. To accelerate the rate of microbial biodegradation of a toxic, synthetic chemical, one needs to understand the nature of regulation of the structural genes, and the mechanism of action as well as evolution of such regulatory genes. However, even when a microorganism becomes available for effective degradation and removal of a toxic chemical, it cannot necessarily be used in bioremediation unless its pathogenic potential to local populations has been determined. This proposal has two major goals. The first to understand how degradative pathways for simple, as well as somewhat recalcitrant, chlorinated compounds evolve in nature. We are particularly interested in the evolution and the mode of action of regulatory genes that regulate the level of expression of the structural genes in the biodegradative pathway. Our second goal is to develop both conceptual and technical understanding and approaches to assess the pathogenic potential of a bioremediating organism. The progress achieved and the ways we intend to meet our goals are detailed in this proposal