The American cockroach, Periplaneta americana (L.), is a notorious urban pest. It has developed insecticidal resistance to commonly used insecticides. Cantharidin (CTD) is a defensive toxin derived from blister beetles. It has been verified to have insecticidal toxicity in a range of pests. In this study, we determined the ingestion toxicity of CTD and norcantharidin (NCTD) to P. americana to test whether they had the potential to be effective against P. americana. Bioassays revealed that CTD produces toxicity against P. americana. The median lethal concentration (LC₅₀) value of CTD was 50.92 μg/mL, while NCTD displayed nearly no toxicity against P. americana. The inhibition assays of serine/threonine protein phosphatases (PSPs) in P. americana indicated that CTD and NCTD could inhibit PSPs. The value of the half maximal inhibitory concentration (IC₅₀) of CTD was 7.21 ± 0.94 μM, whereas that of NCTD was higher, at 31.65 ± 3.87 μM. Furthermore, the inhibition effect of CTD on the serine/threonine protein phosphatase type 5 of P. americana (PaPP5) was superior to that of NCTD. Specifically, the IC₅₀ of CTD reached 0.39 ± 0.04 μM, while the IC₅₀ of NCTD was 1.87 ± 0.23 μM. This study paves the way for insect-derived agents (CTD) to be applied toward controlling P. americana and contributes to the development of novel insecticides based on PP5 as a target.

中文翻译：

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5型丝氨酸/苏氨酸蛋白磷酸酶的抑制作用介导Cantharidin毒性以控制美洲大i（L.）

美国蟑螂美洲大plane（Periplaneta americana，L。）是一种臭名昭著的城市害虫。它对常用的杀虫剂具有抗药性。Cantharidin（CTD）是一种源自水泡甲虫的防御性毒素。已证实其对多种害虫均具有杀虫毒性。在这项研究中，我们确定了CTD和降冰藓素（NCTD）对美洲假单胞菌的摄入毒性，以测试它们是否具有有效对抗美洲假单胞菌的潜力。生物测定法显示，CTD对美洲假单胞菌产生毒性。CTD的致死浓度中位数（LC ₅₀）值为50.92μg/ mL，而NCTD对美国假单胞菌几乎没有毒性。美洲P.丝氨酸/苏氨酸蛋白磷酸酶（PSPs）的抑制试验表明，CTD和NCTD可以抑制PSP。CTD的半数最大抑制浓度（IC ₅₀）值为7.21±0.94μM，而NCTD的半数最大抑制浓度为31.65±3.87μM。此外，CTD对美洲假单胞菌（PaPP5）的5型丝氨酸/苏氨酸蛋白磷酸酶的抑制作用优于NCTD。具体而言，CTD的IC ₅₀为0.39±0.04μM，而NCTD的IC ₅₀为1.87±0.23μM。这项研究为将昆虫源性药物（CTD）应用于控制美洲原虫铺平了道路 并有助于开发以PP5为目标的新型杀虫剂。