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为进一步探讨斑蝥素的杀虫作用机理,本研究采用叶碟饲喂法处理粘虫Mythimna separata(Walker)5龄幼虫,测定了饲喂处理后6,12,24,36和48h试虫体内羧酸酯酶(CarE)、酸性磷酸酯酶(ACP)、碱性磷酸酯酶(ALP)、谷胱甘肽S-转移酶(GST)和细胞色素P450Ο-脱甲基酶及多酚氧化酶(PPO)的活性。结果表明:斑蝥素可显著激活羧酸酯酶,处理后48h酶比活力最大,为同期对照的1.68倍;酸性磷酸酯酶在处理后6和12h活性变化不明显,处理24h后逐渐被激活,且与对照差异显著(P<0.05);明显抑制碱性磷酸酯酶,且随着处理时间的延长,抑制作用增强;对Ο-脱甲基酶表现为先抑制后激活的趋势;谷胱甘肽S-转移酶表现出先激活后抑制的影响;离体活体条件下均可显著抑制PPO活性。可见,斑蝥素可明显影响昆虫的代谢酶系,且其对碱性磷酸酶和多酚氧化酶的抑制作用可能与其毒杀作用有关。
In order to further investigate the insecticidal action mechanism of cantharidin, the 5th instar larvae of Mythimna separata (Walker) were treated with leaf disc feeding method to determine the carboxylation of carboxymethylcellulose at 6, 12, 24, 36 and 48 h CarE, ACP, ALP, GST, and cytochrome P450 O-demethylase and polyphenol oxidase PPO) activity. The results showed that cantharidin could activate carboxylesterase significantly, and the maximum specific activity 48h after treatment, which was 1.68 times that of the control at the same period. The activity of acid phosphatase was not obvious at 6 and 12 h after treatment, (P <0.05); significantly inhibited alkaline phosphatase, and with the extension of treatment time, the inhibitory effect was enhanced; the activity of O-demethylase was first inhibited after activation; glutathione Peptide S-transferase showed the first post-activation inhibitory effect; in vitro activity can significantly inhibit PPO activity. Visible, cantharidin can significantly affect insect metabolic enzymes, and its inhibition of alkaline phosphatase and polyphenol oxidase may be related to its toxic effects.