杀虫剂敌敌畏和除草剂丁草胺对斑腿树蛙蝌蚪的遗传毒性

敌敌畏和丁草胺是我国农田中使用最普遍的杀虫剂和除草剂,这些农田化学物质对当地的水生动物及种群造成很大威胁.本文以广泛分布于我国南方农田区域的斑腿树蛙蝌蚪为研究对象,用碱性单细胞电泳方法(或慧星试验)对暴露在不同浓度的敌敌畏(2.08,4.16,6.24,8.32,10.40 mg/L)和丁草胺(0.1025,0.205,0.410,0.820,1.230 mg/L)溶液中的蝌蚪进行了遗传毒性的检测.结果表明在实验室条件下,随着农药浓度的增加,蝌蚪的DNA损伤(DNA尾长与尾宽比)随之增加;敌敌畏浓度为2.08 mg/L和丁草胺浓度为0.41 mg/L时,对蝌蚪造成显著的损伤,而且农药的剂量与蝌蚪的DNA损伤(DNA尾长与尾宽比)呈显著的线性关系敌敌畏,y=1.136±0.0083x,r=0.957,P<0.01;丁草胺,y=0.968±0.0093x,r=0.964,P<0.01.本研究表明这两种农药对我国的两栖动物具有遗传毒性作用;同时也表明,在检测环境污染物对蝌蚪的基因毒性方面,碱性单细胞电泳分析是一种合适的方法动物学报 51(3)447-454,2005].

Genotoxicity of the pesticide Dichlorvos and herbicide Butachlor in Rhacophorus megacephalus tadpoles

Dichlorvos and Butachlor are,respectively,the most commonly used pesticide and herbicide in Chinese agriculture.Run-off from fields treated with these agricultural chemicals contaminates various bodies of water,from ditches to lakes and rivers,and could have a negative impact on indigenous aquatic fauna.In this report,the alkaline single-cell gel electrophoresis assay or comet assay was performed on erythrocytes from Rhacophorus megacephalus tadpoles following whole-body exposure to increasing concentrations of the tested substances.The animal is common in the agricultural regions of South China.Tadpoles treated for 24 h in the laboratory with different concentrations of the test agents,2.08,4.16,6.24,8.32,10.40 mg/L for Dichlorvos and 0.1025,0.205,0.410,0.820,1.230 mg/L for Butachlor,had significant,dose-responsive increases in the levels of DNA damage,as measured by the mean DNA length:width ratio.Concentrations as low as 2.08 mg/L Dichlorvos and 0.41 mg/L Butachlor resulted in significant increases in DNA damage in the tadpoles.There was a strong linear correlation between the mean DNA length-to-width ratios and the concentrations of the two test substances:Dichlorvos,y=1.136±0.0083x,r=0.957,P<0.01;Butachlor,y=0.968±0.0093x,r=0.964,P<0.01.The results of this study indicate that these two commonly used agricultural chemicals produce DNA damage in an indigenous Chinese amphibian,and that using the Comet assay may be useful for measuring DNA damage in tadpoles exposed in the fieldActa Zoologica Sinica 51(3):447-454,2005].