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BIOLOGY OF PARAQUAT, FREE RADICALS & TRACE METALS

百草枯的生物学，自由基

基本信息

批准号：
3252354
负责人：
MORDECHAI CHEVION
金额：
$ 25.53万
依托单位：
OKLAHOMA MEDICAL RESEARCH FOUNDATION
依托单位国家：
美国
项目类别：
财政年份：
1987
资助国家：
美国
起止时间：
1987-05-01 至 1991-04-30
项目状态：
已结题

项目摘要

This proposal is focused on the mechanism of the tissue injury caused by exposure to the herbicide, paraquat. Because of its inherent chemical stability, paraquat may pose a serious problem in the environment, as a consequence of its accumulation in soil and crops. Subsequently, it may enter into the water supply and food chain and eventually into the human body. Paraquat in vivo undergoes an enzyme-catalyzed cyclic one-electron reduction and reoxidation which results in the formation of superoxide radicals. Tissue injury caused by paraquat is believed to be associated with molecular oxygen production. The molecular oxygen-induced tissue injury had been often observed to be greatly enhanced by traces of transition metals. An obligatory role for traces of Cu and Fe in the mediation of tissue injury caused by paraquat has been recently demonstrated in a bacterial model and in mice. The experiments proposed in this application are designed to a) determine the degree of correlation between the dose of paraquat, the cellular level of transition metals, and the observed intensity of in vivo production of free radicals, and b) determine the degree of correlation between the dose of paraquat, the cellular level of transition metals, and the observed severity of injury to the organism. An evaluation of the results of studies described in a) and b) should provide insights into the relationship between the level of in vivo free radical production and the degree of biological damage. The dose of paraquat will be varied and the cellular level of transition metals will be manipulated in order to determine how these parameter affect both free radical production and cellular injury. Two biological models will be used: E. coli and mice. In studying each model we will employ three recently developed methods for monitoring the in vivo production of free radicals: 1) HPLC combined with electrochemical detection (HPLC-ECD) of 8-OH-2-deoxyguanosine in DNA, as a measure of .OH attack on chromosomes and subsequent damage to DNA structure, 2) HPLC-EDC analyses of the conversion of salicylate into dihydroxybenzoate as a reporter of the production of .OH radicals in the cytoplasm of cells, and 3) electron paramagnetic resonance (EPR) determination of spin adducts formed from a variety of oxygen- and carbon-centered free radicals as a measure of free radical production in cell membranes. This proposal offers a unique approach for critical evaluation of the role of free radicals in tissue injury in vivo.

本研究的重点是探讨黄斑狼疮引起组织损伤的机制。接触除草剂百草枯。因为它固有的化学物质稳定性，百草枯可能会在环境中造成严重问题，因为它在土壤和作物中积累的后果。随后，它可能会进入供水和食物链，并最终进入人类尸体。百草枯在体内经历酶催化的环单电子导致超氧化物形成的还原和再氧化激进分子。百草枯引起的组织损伤被认为与分子氧的生产。分子氧诱导的组织人们经常观察到，由于有微量的过渡金属。微量铜和铁在环境中的作用百草枯引起的组织损伤的调解是最近的研究在细菌模型和小鼠身上进行了演示。中提出的实验此应用程序用于a)确定关联度在百草枯的剂量、过渡金属的细胞水平和观察到的体内产生自由基的强度，以及b) 确定百草枯剂量、过渡金属的细胞水平，以及观察到的损伤严重程度有机体。对a)和中所述研究结果的评价 B)应提供对年收入水平之间关系的见解体内自由基的产生和生物损伤的程度。剂量百草枯的含量会有所不同，过渡金属的细胞水平也会不同被操纵以确定这些参数如何影响两个自由自由基产生和细胞损伤。两个生物模型将是使用：大肠杆菌和小鼠。在研究每个模型时，我们将使用三个新近开发的监测体内产生游离素的方法自由基：1)高效液相色谱-电化学检测法(HPLC-ECD) DNA中的8-OH-2-脱氧鸟苷，作为.oh对染色体和 DNA结构的后续损伤，2)转化的高效液相-电子捕获分析将水杨酸转化为二羟基苯甲酸作为记者生产的.oh 细胞质中的自由基，以及3)电子顺磁共振 (EPR)测定由各种氧和-形成的自旋加合物以碳为中心的自由基作为自由基产生的一种衡量标准细胞膜。该提案为关键问题提供了一种独特的方法体内自由基在组织损伤中的作用评价。