National Bureau of Fish Genetics Resources, Canal Ring Road, P O-Dilkusha, Lucknow 226002, India.
Arch Environ Contam Toxicol. 2010 Jan;58(1):123-30. doi: 10.1007/s00244-009-9354-3. Epub 2009 Jun 26.
Malathion [S-(1,2-dicarboethoxyethyl) O, O-dimethyl phosphorodithioate] is a widely used organophosphorus insecticide throughout the world. However, limited efforts have made to study its genotoxic effect in different fish tissues. The present investigation was aimed to assess the genotoxic potential of the pesticide to the freshwater teleost fish Channa punctatus at sublethal concentrations using the micronucleus test and comet assay. Initially, the 96-h LC50 value of commercial-grade malathion (50% EC) was determined as 5.93 ppm in a semistatic system. Based on LC50, three test concentrations (viz. sublethal I, sublethal II, and sublethal III) were determined to be 1.48, 0.74, and 0.59 ppm, respectively, and the fish specimens were exposed to these concentrations. Tissue samplings were done on days 0, 1, 3, 7, 15, 22 and 29 of malathion exposure for assessment of the induction of micronuclei (MN) frequency and DNA damage. The MN formation in the peripheral blood cells was found to be significantly higher (p < 0.05) in the treated specimens at all sampling intervals compared to the control. The MN frequency reached maximum on days 3 and 7 at sublethal I and II concentrations, respectively, followed by a nonlinear decline with the progression of the experiment. Similarly, significant effects (p < 0.05) of both concentration and time of exposure were observed on DNA damage in the gill, kidney, and lymphocytes. All of the tissues exhibited a concentration-dependent increase in DNA damage up to day 3, followed by a nonlinear decrease with the duration of exposure. A comparison of the extent of DNA damage among the tissues showed the sensitivity of gill tissue to malathion.
马拉硫磷[硫代磷酸 S-（1,2-二羧乙基）酯 O,O-二甲基]是一种在世界各地广泛使用的有机磷杀虫剂。然而，对于不同鱼类组织中该农药的遗传毒性作用，研究工作有限。本研究旨在采用微核试验和彗星试验评估亚致死浓度的农药对淡水鱼类 Channa punctatus 的遗传毒性潜力。首先，在半静态系统中确定了商业级马拉硫磷（50% EC）的 96 小时 LC50 值为 5.93 ppm。基于 LC50 值，确定了三个测试浓度（即亚致死 I、亚致死 II 和亚致死 III）分别为 1.48、0.74 和 0.59 ppm，并用这些浓度暴露鱼类标本。在马拉硫磷暴露的第 0、1、3、7、15、22 和 29 天进行组织采样，以评估微核（MN）频率和 DNA 损伤的诱导。与对照组相比，在所有采样时间点，处理标本外周血细胞中的 MN 形成明显更高（p < 0.05）。在亚致死 I 和 II 浓度下，MN 频率分别在第 3 天和第 7 天达到最大值，随后随着实验的进行呈非线性下降。同样，在鳃、肾脏和淋巴细胞中，暴露浓度和时间对 DNA 损伤均有显著影响（p < 0.05）。所有组织的 DNA 损伤均随暴露浓度的增加呈浓度依赖性增加，直至第 3 天，随后随暴露时间的延长呈非线性下降。对组织间 DNA 损伤程度的比较表明，鳃组织对马拉硫磷敏感。
