以小菜蛾（Plutella xylostella）的消化系统为靶标的化学杀虫剂至今尚未报道。创制一款具有新型作用机制的用于小菜蛾防控的杀虫剂仍然是一个巨大的挑战。为了探索以小菜蛾中肠为靶标的新型杀虫剂，设计并合成了一系列以二氟甲基和硒修饰的新型氟唑硒脲（FASU）化合物。室内杀虫测试结果表明，化合物B4对小菜蛾的杀虫活性最高，3龄和2龄小菜蛾幼虫72 h的半致死浓度LC₅₀值分别为32.33，4.63 μg mL^-1。化合物B4导致小菜蛾中肠严重受损，诱发产生众多的红色斑点。超微结构显示小菜蛾中肠围食膜降解，上皮组织肿胀，微绒毛断裂及细胞消融解体。化合物B4亚致死浓度（LC₁₀，LC₂₅ 和LC₅₀）处理后，幼虫发育缓慢，幼虫历期显著延长，蛹重，化蛹率，羽化率均显著下降。此外，化合物B4可诱发畸形蛹，导致成虫不能破茧或翅膀畸形不能飞翔。以上结果表明，氟唑硒脲化合物对对小菜蛾具有较好的杀虫活性，在亚致死浓度下，可以降低小菜蛾的种群数量。值得注意的是，氟唑硒脲是首次报道的可诱导小菜蛾中肠损伤的合成杀虫剂先导化合物，其作用机理与现有商品化杀虫剂均不同。

The acetylcholinesterase 2 (AChE2) cloned from Plutella xylostella was first successfully expressed in methylotrophic yeast Pichia pastoris GS115.  One transformant with high-level expression of the recombinant AChE (rAChE, 23.2 U mL^–1 in supernatant) was selected by plating on increasing concentrations of antibiotic G418 and by using a simple and specific chromogenic reaction with indoxyl acetate as a substrate.  The maximum production of rAChE reached about 11.8 mg of the enzyme protein per liter of culture.  The rAChE was ?rst precipitated with ammonium sulfate (50% saturation) and then puri?ed with procainamide af?nity column chromatography.  The enzyme was puri?ed 12.1-fold with a yield of 22.8% and a high speci?c activity of 448.3 U mg^–1.  It was sensitive to inhibition by methamidophos and pirimicarb, the calculated 50% inhibitory concentration (IC₅₀) values of the two pesticides were 0.357 and 0.888 mg L^–1, respectively, and the calculated 70% inhibitory concentration (IC₇₀) values were 0.521 and 0.839 mg L^–1, respectively.  The results suggested that it has a potential application in the detection of pesticide residues.

Insecticidal activities of the petroleum ether-, chloroform-, ethyl acetate-, and water-soluble fractions of the methanolicextract of Ficus sarmentosa var. henryi were assayed against Musca domestica adults. The chloroform- and ethyl acetatesolublefractions were the most active with 92.6 and 88.9% mortalities (24 h after treatment) respectively. Therefore, thetwo fractions were combined and four compounds, isolated from the fractions by activity-guided fractionation, wereelucidated as 7-hydroxycoumarin, apigenin, eriodictyol, and quercetin by spectroscopic method and displayed excellentinsecticidal activities against adults of M. domestica and 4th instar larva of Aedes albopictus. Among those, 7-hydroxycoumarin showed the strongest insecticidal activities with lethal concentrations (LC50) values of 72.13 μg g-1sugar and 4.87 μg mL-1 (48 h after treatment) against the test insects respectively. The cytoxicities of these compounds onBTI-Tn-5B1-4 cell were also investigated for the insecticidal mechanism and found that quercetin represented superiorinhibitory activity with MTT assay and reactive oxygen species (ROS) against BTI-Tn-5B1-4 cell, but slightly weaker thanthat of the positive control (azadirachtin) and significantly greater than the negative control (DMSO only). Meanwhile,eriodictyol demonstrated the strongest effect on the mitochondrial membrane potentials (MMP). In conclusion, based ontheir comparative toxicities to commercial insecticides and their cytotoxic effects, some of the compounds from theF. sarmentosa have potential as botanical insecticides.