摘要:
研究了菲和芘在单一低剂量污染胁迫下对蚯蚓(Eisenia fetida)体内细胞色素P450酶系和抗氧化酶系的影响.通过滤纸接触染毒法,检测蚯蚓细胞色素P450含量以及超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)的活性.结果表明,在供试浓度范围内,蚯蚓体内细胞色素P450含量和三种抗氧化酶活性均对毒物产生了不同程度的响应.菲和芘在蚯蚓体内的代谢诱发了细胞色素P450总含量的增加,且在此过程中有活性氧自由基产生.不同酶对毒性效应响应的域值不同,其敏感性大为:P450>SOD(POD)>CAT.根据四个指标对污染物浓度响应的域值不同,可将四者联合应用互为补充作为一套生物标记物体系,以满足污染物不同暴露浓度下土壤的毒理诊断,增强指示的敏感性和有效性.
Abstract:
The influence of phenanthrene and pyrene on cytochrome P450 and antioxidant enzymes of earthworms(Eisenia fetida)was studied. By means of contacting with contaminated filter paper, earthworms were exposed to the pollutants. Earthworm was used to detect total cytochrome P450 content and the activities of superoxide dismutases(SOD), guaiacol peroxidases(POD) and catalase(CAT). Results indicated that, within tested concentrations, total P450 contents and the activities of three antioxidant enzymes had responses to the toxicities of phenanthrene and pyrene.Metabolism of these two PAHs in earthworm induced the increasing of P450 content, and reactive oxygen species could be generated as by product in that process. In contrast, the oxidative stress of earthworms caused by pyrene was harder than by phenanthrene. Concentration thresholds of response for different enzymes differed,and their sensibilities to the PAH pollutants follow the sequence of P450 >SOD (POD)> CAT.Therefore, the four indexes could be used together as a suit of biomarkers to satisfy the diagnosis in different exposure concentrations and to enhance the sensitivity and effectivity of indicating.
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