State Key Laboratory of Biocontrol, College of Life Sciences, Sun Yat-sen University, No. 135 XingangXi Road, Guangzhou, Guangdong 510275, People's Republic of China.
J Econ Entomol. 2012 Aug;105(4):1164-70. doi: 10.1603/ec12014.
We studied the effect of combining microbial pesticides with camptothecin (CPT) on the mortality of two lepidopteran insects: Trichoplusia ni (Hübner) and Spodoptera exigua (Hübner). CPT is an alkaloid that is often used as an anticancer agent. Here, CPT was evaluated as a microbial pesticide synergist of Bacillus thuringiensis (Bt) and insect baculovirus. The toxicity of CPT and its synergistic effects on two microbial pesticides were studied using the diet overlay method. Bioassay results showed that CPT significantly enhances the toxicity of Bt variety kurstaki to S. exigua and T ni. In addition, CPT strongly enhanced the infectivity of Autographa californica (Speyer) multinucleocapsid nucleopolyhedrovirus (AcMNPV) and S. exigua nucleopolyhedrovirus (SeMNPV). Using light microscopy, we found that CPT disrupts the peritrophic membrane of T. ni larvae and severely affects the structure of the midgut, resulting in an abnormal gut lumen morphology. We speculate that CPT increases toxicity by affecting the permeability of the peritrophic membrane.
我们研究了将微生物农药与喜树碱 (CPT) 结合使用对两种鳞翅目昆虫：斜纹夜蛾 (Trichoplusia ni (Hübner)) 和甜菜夜蛾 (Spodoptera exigua (Hübner)) 的死亡率的影响。CPT 是一种生物碱，常被用作抗癌药物。在这里，CPT 被评估为苏云金芽孢杆菌 (Bt) 和昆虫杆状病毒的微生物农药增效剂。使用饮食覆盖法研究了 CPT 的毒性及其对两种微生物农药的增效作用。生物测定结果表明，CPT 显著增强了 Bt 亚种 kurstaki 对 S. exigua 和 T ni 的毒性。此外，CPT 强烈增强了美洲棉铃虫多核衣壳核多角体病毒 (AcMNPV) 和甜菜夜蛾核多角体病毒 (SeMNPV) 的感染力。使用光学显微镜，我们发现 CPT 破坏了 T. ni 幼虫的围食膜，并严重影响了中肠的结构，导致异常的肠腔形态。我们推测 CPT 通过影响围食膜的通透性来增加毒性。
