Hebei Key Laboratory of Animal Physiology, Biochemistry and Molecular Biology, Hebei Collaborative Innovation Center for Eco-Environment, Ministry of Education Key Laboratory of Molecular and Cellular Biology, College of Life Sciences, Hebei Normal University, Shijiazhuang 050024, China.
Hebei Key Laboratory of Animal Physiology, Biochemistry and Molecular Biology, Hebei Collaborative Innovation Center for Eco-Environment, Ministry of Education Key Laboratory of Molecular and Cellular Biology, College of Life Sciences, Hebei Normal University, Shijiazhuang 050024, China..
Pestic Biochem Physiol. 2024 Sep;204:106075. doi: 10.1016/j.pestbp.2024.106075. Epub 2024 Aug 5.
Currently, the primary strategy for tick control relies on chemical agents. Pyrethrins, which are botanically derived compounds, have demonstrated efficacy in controlling ticks without posing a risk to human or animal health. However, research into pyrethrins' metabolic mechanisms remains sparse. Cystatin, as a reversible binding inhibitor of cysteine protease, may be involved in the initiation of pyrethrin detoxification of Haemaphysalis doenitzi. In this study, two novel cystatins were cloned, HDcyst-3 and HDcyst-4, the relative expression of which was highest in the Malpighian tubules compared with the tick midguts, salivary glands, and ovaries. Prokaryotic expression and in vitro studies revealed that cystatins effectively inhibit the enzymatic activities of cathepsins B and S. RNAi results showed that the reduction of cystatins significantly decreased the engorgement weight, egg mass weight, and egg hatching rate of adult female ticks, and prolonged feeding time by two days. The control rate of rHDcyst-3 and rHDcyst-4 protein vaccination against female adults were 55.9% and 63.2%, respectively. In addition, the tick immersion test showed that cypermethrin and λ-cyhalothrin had significant acaricidal effects against adult unfed H. doenitzi. The qPCR result indicated that compared with the control group, the expression of HDcyst-3 and HDcyst-4 was markedly decreased in the sublethal cypermethrin and λ-cyhalothrin group at LC. Enzyme activity showed that cypermethrin and λ-cyhalothrin could significantly induce the activities of glutathione S-transferase (GST), carboxylesterase (CarE), and acetylcholinesterase (AchE). The aforementioned results provided indirect evidence that cystatin plays an important role in pyrethrin detoxification and provides a theoretical basis for future acaricide experiments and pest management.
目前，蜱虫防治的主要策略依赖于化学药剂。除虫菊酯是一种源自植物的化合物，已被证明在控制蜱虫方面有效，且不会对人类或动物健康造成风险。然而，关于除虫菊酯代谢机制的研究仍然很少。半胱氨酸蛋白酶抑制剂胱抑素可能参与了 Haemaphysalis doenitzi 对除虫菊酯的解毒作用。在这项研究中，克隆了两种新型胱抑素，即 HDcyst-3 和 HDcyst-4，与蜱虫的中肠、唾液腺和卵巢相比，它们在马氏管中的相对表达水平最高。原核表达和体外研究表明，胱抑素能有效抑制组织蛋白酶 B 和 S 的酶活性。RNAi 结果表明，胱抑素的减少显著降低了雌蜱的饱血体重、卵团重量和卵孵化率，并使取食时间延长两天。rHDcyst-3 和 rHDcyst-4 蛋白疫苗对成年雌蜱的防治率分别为 55.9%和 63.2%。此外，蜱虫浸浴试验表明，氯氰菊酯和 λ-氯氟氰菊酯对未吸血的 H. doenitzi 成虫具有显著的杀蜱作用。qPCR 结果表明，与对照组相比，亚致死浓度的氯氰菊酯和 λ-氯氟氰菊酯组中 HDcyst-3 和 HDcyst-4 的表达明显降低。酶活性表明，氯氰菊酯和 λ-氯氟氰菊酯能显著诱导谷胱甘肽 S-转移酶（GST）、羧酸酯酶（CarE）和乙酰胆碱酯酶（AchE）的活性。上述结果为胱抑素在除虫菊酯解毒中发挥重要作用提供了间接证据，并为未来的杀蜱剂实验和害虫管理提供了理论依据。
