Amanchi Nageswara Rao, Hussain Mohd Masood
Protozoology and Environmental Toxicology Lab., Department of Zoology, Osmania University, Hyderabad - 500 007, India.
J Environ Biol. 2010 Sep;31(5):603-7.
Experiments were conducted to evaluate the toxic effects ofmonocrotophos in ciliate models Paramecium caudatum and Oxytricha fallax. In acute toxicity studies higherconcentrations of monocrotophos caused marked increase in mobility of cells exhibiting rocking movements within two mins of exposure but were decreased after 30 mins. LC50 value by mortality curve for 3 hr acute toxicity test of Oxytricha fallax and Paramecium caudatum was found 307.744 +/- 33.27 mg l(-1) and 332.284 +/- 57.52 mg l(-1) respectively. Oxytricha fallax was found sensitive than Paramecium caudatum to monocrotophos. In acute exposure cells showed deformities such as swelling, oval shaped deformity and in higher concentrations shortening of longitudinal axis with blackening of cytoplasm occurred. The length of paramecia was reduced prominently. Similarly enlargement of contractile vacuole and stress egestion of food vacuoles was also observed. The morphological studies showed the changes in shape, size, colour and width of Paramecia and Oxytricha. Frequencies of macronuclear aberrations were significant showing deformities such as rod shaped, elongation, fragmentation, diffusion and total absence of nucleus and were concentration dependent. The data provided in the present study on interaction of pesticides with nuclear structure can be of immense value because most of these pesticides have been reported to have carcinogenic, mutagenic and teratogenic properties.
进行了实验以评估久效磷对纤毛虫模型尾草履虫和尖毛虫的毒性作用。在急性毒性研究中，较高浓度的久效磷在暴露两分钟内导致细胞运动性显著增加，表现出摇摆运动，但30分钟后下降。通过死亡率曲线得出，尖毛虫和尾草履虫3小时急性毒性试验的LC50值分别为307.744±33.27mg l(-1)和332.284±57.52mg l(-1)。发现尖毛虫比尾草履虫对久效磷更敏感。在急性暴露中，细胞出现畸形，如肿胀、椭圆形畸形，在较高浓度下，纵轴缩短，细胞质变黑。草履虫的长度显著缩短。同样观察到收缩泡增大和食物泡应激性排出。形态学研究显示了草履虫和尖毛虫在形状、大小、颜色和宽度上的变化。大核畸变频率显著，表现出棒状、伸长、断裂、扩散和完全无核等畸形，且与浓度有关。本研究中提供的关于农药与核结构相互作用的数据可能具有巨大价值，因为据报道这些农药大多具有致癌、致突变和致畸特性。
