摘要:
为了研究大田软海绵酸(okadaic acid,OA)对生物胚胎组织发育过程的毒性作用机制,采用静水和半静水实验法,用OA毒素与过滤海水按等对数间距分设5个浓度组,同时以过滤海水为对照组,对人工养殖的黑鲷鱼卵和仔鱼进行了毒性实验。实验结果表明:一定浓度的OA使鱼卵的死亡率和孵出仔鱼的畸形率升高,但对孵化率的影响较弱。OA对黑鲷仔鱼的24、48、72和96 h的LC50分别为51.63、45.58、37.97和25.72 nmol·L-1,仔鱼体内毒性蓄积程度也随时间逐渐减弱。OA毒素对仔鱼的谷胱甘肽过氧化物酶(GSH-PX)和酸性磷酸酶(ACP)的活性均有诱导作用,与对ACP的影响相比,OA毒素对GSHPX活性的诱导作用更为突出。此外,OA毒素还会对黑鲷仔鱼的肝脏细胞的核酸代谢及DNA合成有一定的影响,使得RNA和DNA的含量比值发生显著变化。
Abstract:
In order to study the acute toxicity of okadaic acid to the embryonic development of marine life as well as its biochemical mechanism, acute toxicity experiments were conducted on the eggs and larvae of Sparus macrocephalus using static and semi-static method. Results showed that both mortality and malformation of eggs significantly increased under the exposure of okadaic acid, while the hatchability rate was relatively less affected. The median lethal concentrations of larvae were 51.63, 45.58, 37.97 and 25.72 nmol L-1, respectively, after exposure of 24, 48, 72 and 96 hours to okadaic acid. A decrease in toxic accumulation in the bodies of the larvae was observed with the extension of exposure time. When exposed to okadaic acid, the activity of GSH-PX was induced significantly, while the activity of ACP was relatively less affected. Moreover, okadaic acid also affected the metabolism of nucleic acid and DNA synthesis in larval hepatocyte, which led to a significant change in the RNA/DNA ratio.
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