MICROBIAL DEGRADATION OF AGENT ORANGE

描述：（改编自研究者摘要）环境放行 大量的合成氯化化合物， 除草剂/杀虫剂、溶剂、制冷剂等，创造了重大 对它们对人类健康的影响表示关切， 许多这样的化合物的持久性。 这些化合物的持久性是 反映了自然微生物无法利用它们作为 唯一的碳和能源来源。 许多微生物可以利用简单的 氯化化合物，如3-氯苯甲酸酯（3Cba）或 2，4-二氯苯氧基乙酸酯（2，4-D）作为其唯一碳源，但不能 使用较高的氯化形式，如2，4，5-三氯苯氧基乙酸 （2，4，5-T）及其他。 在强选择条件下，2，4，5-T 作为碳的唯一主要来源（定向进化），它一直是 可以分离洋葱假单胞菌AC 1100的菌株， 2，4，5-T作为其唯一的碳和能量来源。 的分子克隆 3Cba/2，4-D和2，4，5-T降解基因的研究表明， 而3Cba和2，4-D异化的氯儿茶酚（clc）基因是 高度同源，2，4，5-T降解（degradative，degrad 与大量假单胞菌和其他 细菌 申请人提出实验以了解 基因及其产物，以确定2，4，5-T是如何 AC1100及其调节模式的降解。 测序和 将尝试过表达大量的p53基因以获得 关于允许有效渗透的酶的作用的信息 2，4，5-T及其随后的脱氯和氧化。 类似地第 儿茶酚正调控蛋白 基因将被纯化，并且其与启动子的结合模式将被改变。 结构基因将被描绘出来，以定义这一性质。 蛋白质-DNA相互作用的猫基因的功能性表达。 这些 数据将提供有关进化模式的有价值的信息， 结构和调节基因在自然界中以及在恒化器中， 应对氯化化合物的释放和供应。

DESCRIPTION: (Adapted from investigators abstract) Environmental release of a large number of synthetic chlorinated compounds in the form of herbicides/pesticides, solvents, refrigerants etc., has created major concerns with regard to their effect on human health because of the persistence of many such compounds. The persistence of these compounds is a reflection of the inability of natural microorganisms to utilize them as a sole source of carbon and energy. Many microorganisms can utilize simple chlorinated compounds such as 3-chlorobenzoate (3Cba) or 2,4-dichlorophenoxyacetate (2,4-D) as their sole carbon source but cannot utilize higher chlorinated forms such as 2,4,5-trichlorophenoxy acetic acid (2,4,5-T) and others. Under strong selection in a chemostat with 2,4,5-T as the only major source of carbon (directed evolution), it has been possible to isolate a strain of Pseudomonas cepacia AC1100 that can utilize 2,4,5-T as its sole source of carbon and energy. Molecular cloning of the genes both for 3Cba/2,4-D as well as 2,4,5,-T degradation has shown that while the chlorocatechol (clc) genes for 3Cba and 2,4-D dissimilation are highly homologous, the 2,4,5-T degradative (tft) genes show no homology with any of the genomic DNA of a large number of pseudomonads and other bacteria. The applicant proposes experiments to understand the nature of the tft genes and their products to determine exactly how 2,4,5-T is degraded by AC1100 and its mode of regulation. Sequencing and hyperexpression of a number of tft genes will be attempted to obtain information about the role of enzymes that allow efficient permeation of 2,4,5-T and its subsequent dechlorination and oxidation. Similarly, a regulatory protein involved in the positive regulation of catechol (cat) genes will be purified and its mode of binding with the promoter of the structural genes will be delineated to define the nature of this protein-DNA interaction for functional expression of the cat genes. These data would provide valuable information about the mode of evolution of structural and regulatory genes in nature as well as in chemostats in response to the release and availability of chlorinated compounds.