Zeng Rune, Yu Xing, Tan Xing, Ye Shan, Ding Zhong
College of Plant Protection, Hunan Agricultural University, Changsha 410128, China.
College of Plant Protection, Hunan Agricultural University, Changsha 410128, China; Hunan Provincial Key Laboratory for Biology and Control of Plant Disease and Insect Pests, Changsha 410128, China.
Pestic Biochem Physiol. 2017 May;138:84-90. doi: 10.1016/j.pestbp.2017.03.005. Epub 2017 Mar 6.
Deltamethrin belongs to the class of synthetic pyrethroids, which are being widely used as insecticides in agricultural practices. Voltage-gated sodium channels (VGSCs) are the primary targets of these chemicals for toxicity to insects. Caenorhabditis elegans (C. elegans) does not have VGSCs but is susceptible to deltamethrin. Recent findings have suggested that pyrethroids can affect voltage-gated calcium channels (VGCCs). However, it remains elusive whether deltamethrin induces toxicity to C. elegans via modulating the activity of VGCCs. To identify the potential target of deltamethrin, we exposed C. elegans to different concentrations of deltamethrin and Ca channel blockers for different times, characterized the behavioral toxicity of deltamethrin on C. elegans, and determined the expression of egl-19, unc-2, and cca-1, which encode the α1-subunit of the L-, R/N/P/Q-, and T-type VGCC, respectively. We found that deltamethrin inhibited the locomotion, egg-laying and foraging ability of C. elegans in a concentration dependent manner. We also showed that body length of worms on agar plates containing 200mgL deltamethrin for 12h was not significantly different from controls, whereas the cholinesterase inhibitor carbofuran caused hypercontraction which is a characteristic of organophosphates and carbamates, suggesting that deltamethrin's mode of action is distinct from those nematicides. In addition, unc-2 was significantly up-regulated following 0.05mgL deltamethrin exposure for 24h; while egl-19 and cca-1 were significantly up-regulated following 5 and 50mgL deltamethrin exposure for 24h. Further tests of worms' sensitivity and expression of three α1-subunits of VGCC to Ca channel blockers indicate that deltamethrin may induce toxic behavior C. elegans via modulation of the expression of the α1-subunits of VGCC. This study provides insights into the linkage between deltamethrin-induced toxic behavior and the regulation of α1-subunits of VGCC in C. elegans.
溴氰菊酯属于合成拟除虫菊酯类，这类物质在农业生产中被广泛用作杀虫剂。电压门控钠通道（VGSCs）是这些化学物质对昆虫产生毒性的主要靶点。秀丽隐杆线虫（C. elegans）没有VGSCs，但对溴氰菊酯敏感。最近的研究结果表明，拟除虫菊酯可以影响电压门控钙通道（VGCCs）。然而，溴氰菊酯是否通过调节VGCCs的活性对秀丽隐杆线虫产生毒性仍不清楚。为了确定溴氰菊酯的潜在靶点，我们将秀丽隐杆线虫暴露于不同浓度的溴氰菊酯和钙通道阻滞剂中不同时间，表征了溴氰菊酯对秀丽隐杆线虫的行为毒性，并测定了分别编码L型、R/N/P/Q型和T型VGCC的α1亚基的egl-19、unc-2和cca-1的表达。我们发现，溴氰菊酯以浓度依赖的方式抑制秀丽隐杆线虫的运动、产卵和觅食能力。我们还表明，在含有200mg/L溴氰菊酯的琼脂平板上培养12小时的线虫体长与对照组没有显著差异，而胆碱酯酶抑制剂呋喃丹会引起过度收缩，这是有机磷和氨基甲酸酯类农药的特征，表明溴氰菊酯的作用方式与那些杀线虫剂不同。此外，在暴露于0.05mg/L溴氰菊酯24小时后，unc-2显著上调；而在暴露于5mg/L和50mg/L溴氰菊酯24小时后，egl-19和cca-1显著上调。对蠕虫对钙通道阻滞剂的敏感性和三种VGCCα1亚基的表达的进一步测试表明，溴氰菊酯可能通过调节VGCCα1亚基的表达诱导秀丽隐杆线虫的毒性行为。这项研究为溴氰菊酯诱导的毒性行为与秀丽隐杆线虫中VGCCα1亚基的调节之间的联系提供了见解。
