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• 基金项目：

• 杨端
• 中国科学院水生生物研究所

• 周仁珍
• 中国科学院水生生物研究所

• 摘要：水中不同铅浓度(5-500μg/l)急性致毒使白鲢血液中δ-氨基乙酞丙酸脱水酶(ALA-D)活性随铅浓度的增加而呈线性关系下降.温度越高,铅对酶活性的抑制越明显。0.1ppm汞、镉、铜,0.008ppm滴滴涕和0.84ppm对硫磷急性致毒,除对硫磷外对草鱼血ALA-D活性皆没有显著性影响.锌、镉、铜分别与铅混合,降低铅对ALA-D酶的抑制作用,致毒四天,可恢复甚至刺激鱼血ALA-D酶活性.被重金属(包括铅)污染的S湖中白鲢血ALA-D酶表现出明显的抑制作用,但鲤鱼血ALA-D酶却测不出抑制作用.

• Abstract：Silver carp Hypophthalmichthys molitrix was exposed to lead nitrate solution in 0.005, 0.01, 0.1, 1.0, 5.0ppm Pb⁺⁺ for 7 days. It was found that lead had a specific inhibition on the activity of daminolevulinic acid dehyd-ratase (ALA-D)in fish blood. The degree of inhibition was directly related to the concentration of lead in water. It is shown an inverse linear relationship between ALA-D activity and logarithm of lead content in water. Raising water temperature increases lead inhibition.0.1ppm Pb⁺⁺, Hg⁺⁺, Cd⁺⁺, Cu⁺⁺, 0.008ppm DDT and 0.84ppm parathion were used separately on grass carp for 7 days. With the exception of Pb and parathion, other toxicants at the stated concentrations were shown to person no significant inhibition on ALA-D activity.1.84 ×10^-4 M zinc acetate, 4×10^-6M cadmium acetate and 1.86×10^-6M copper acetate were also used separately in combination with 1.72×10^-6M lead acetate to test whether there is any synergistic or antagonistic effect, in separate groups of grass carp. It was found that zinc, cadmium and copper could eliminate completly the inhibitory effect of lead on ALA-D activity in fish blood.Comparison of ALA-D activity between silver carp and common carp from various water bodies reveals that there was no significant difference in ALA-D activity of common carp. However, ALA-D activity of silver carp from a lake which was polluted by heavy metal including lead was depressed sharply.

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