鲫鱼脑AChE活性对水体中石油污染土壤和孔雀石绿的响应

Responses of Brain Acetylcholinesterase(AChE)Activity in Carassius auratus to Crude-Oil-Contaminated Soil and Malachite Green in Aquatic Environment

在室内模拟条件下,通过20d的暴露实验,研究了鲫鱼(Carassius auratus)幼体脑乙酰胆碱酯酶(AChE)活性对水体中存在的石油污染土壤以及孔雀石绿污染的响应。结果表明,水体中低浓度石油污染土壤或孔雀石绿存在时,均会导致鲫鱼脑AChE的活性的增加。随着水体中石油污染土壤数量的增加,AChE活性的变化趋势是先快速升高,降低后又有显著升高。在较低暴露水平(1.000和5.000g·L-1)下,AChE活性显著高于对照组;当暴露水平大于5.000g·L-1后,其AChE活性开始降低,于20.000g·L-1暴露水平时降到对照水平,然后开始升高。50.000g·L-1的石油污染土壤作用下,AChE活性最强,是对照组的1.6倍。水体中的石油污染土壤对鲫鱼脑AChE活性总体表现为诱导作用。相反,鲫鱼脑AChE的活性随孔雀石绿浓度的升高的变化趋势表现为,先缓慢升高,然后快速降低。当暴露浓度为0.023mg·L-1时,AChE活性最大,但激活率仅为13%,与对照组相比没有显著差异。从0.058mg·L-1开始,AChE活性开始降低;到0.116mg·L-1时,AChE活性降到最低,为对照组的79%。总体来说,在所设置的浓度范围内,孔雀石绿对鲫鱼脑AChE的影响不大。从变化趋势上看,水体中孔雀石绿污染对鲫鱼脑AChE活性的抑制效果大于诱导。总之,鲫鱼脑AChE对水体中石油污染土壤较敏感,是较适宜的生物标志物。

Under the indoor stimulant conditions, the responses of brain acetylcholinesterase （ACHE） activity in larval Carassius auratus to different doses of crude-oil-contaminated soil and malachite green in aquatic environment were studied. After a 20-day exposure experiment, results showed that the present of low doses of crude-oil-contaminated soil and malachite green would increase the activity of brain ACHE. With the increase amount of crude-oil-contaminated soil in aquatic environment, the AChE activity was first quickly increased, and then significantly induced after a reduction. The activity of AChE was highly induced even in low exposure doses （ 1.000 and 5.000 g.L^-1）. After that it began to decrease and restored to the control level in 20.000 g.L^-1 dose group. And then the activity of AChE was sharply increased and reached maximum at 50.000 g.L^-1, which was 1.6 times of the control group. As a whole, the activity of brain AChE in Carassius auratus was induced by the crude-oil-contaminated soil. On the contrary, the response tendency of AChE activity to elevating malachite green was first appreciably increased and then fast decreased. The highest AChE activity was found at 0.023 g.L^-1 and it had no significant difference compared to the control, with induction rate merely of 13%. The AChE activity began to decrease from 0.058 g.L^-1and reached minimum at 0.116 g.L^-1, 79% of the control group. The activity of brain AChE in Carassius auratus was not significantly influenced by malachite green at concentrations tested（0-0.116 mg.L^-1）. As a whole, the activity of AChE was suppressed in the test groups exposed to malachite green.In conclusion, responses of brain AChE activity in Carazsius auratus to crude-oil-contaminated soil were sensitive, and the activity of AChE could be the suitable early monitoring index and biomarkers of the existence of oil pollution in aquatic ecosystem.