极地与深海生境链霉菌产生的吲哚咔唑生物碱杀虫活性及作用机理初探

The insecticidal activity and mechanism of Indolocarbazole alkaloid of Streptomyces nitrosporeus isolated from Arctic deep sea

采用浸叶法、微量点滴法测定了吲哚咔唑生物碱对小菜蛾Plutella xyllostella、菜青虫Pieris rapae、甘蓝蚜Brevicoryne brassicae和美国白蛾Hyphantria cunea的生物活性及其对菜青虫幼虫体内酚氧化酶(phenoloxidase)、纤维素酶(cellulase)、几丁质酶(chitinase)和酯酶(esterase)活性的影响。结果表明:吲哚咔唑生物碱对上述害虫具有强触杀、胃毒和生长抑制作用,触杀活性最高为小菜蛾96.55%(48 h),胃毒活性最高为小菜蛾86.21%(48 h)。0.08 mg/m L剂量下对菜青虫幼虫体重生长抑制率为33.47%(4 d)、化蛹率为37.67%,不能正常羽化。同时,吲哚咔唑生物碱对菜青虫幼虫体内各种代谢酶存在不同程度的影响:对酚氧化酶表现抑制作用,抑制至48 h达到最大;对纤维素酶在处理的时间内表现为先抑制后升高;对几丁质酶、酯酶表现激活作用,分别至24 h、72 h达到最大。

The insecticidal activity to Plutella xyllosteUa, Pieris rapae, Brevicoryne brassicae, Hyphantria cunea of Indoloearbazole alkaloid produced by Streptomyces nitrosporeus and mechanism on Pieris rapae were analyzed through leaf soaking and trace titration method. The results showed that Indolocarbazole alkaloid manifested maximum contact toxicity 96.55% and 86. 21% stomach toxicity after 48 h. When the tested insects were treated at the dosage of 0.08 mg/mL, their related growth rate reduced 33.47% （3 d）, the pupation rate from larvae was only 37.67%, and the pupae did not eclose normally. Meanwhile, Indolocarbazole alkaloid imposed different influence on Pieris rapae metabolic enzymes. The inhibition to phenoloxidase in the tested larvae gradually increased until reached the maximum at 48 h and the activity of cellulase was increased after the first suppression throughout the whole test period. The chitinase was activated until reached the maximum at 24 h. As for esterase, it was activated obviously, and the activation increased as the exposure time prolonged and reached the maximum at 72 h.