School of Basic Medicine and Biological Sciences, Soochow University, Suzhou, Jiangsu, 215123, PR China.
School of Basic Medicine and Biological Sciences, Soochow University, Suzhou, Jiangsu, 215123, PR China; Sericulture Institute of Soochow University, Suzhou, Jiangsu, 215123, PR China.
Chemosphere. 2020 Jul;251:126438. doi: 10.1016/j.chemosphere.2020.126438. Epub 2020 Mar 7.
Bombyx mori is an important economic insect. However, the environmental pollution caused by the widespread use of neonicotinoid insecticides has significantly affected the safe production of sericulture. In this paper, we determined the LC of acetamiprid, a kind of neonicotinoid insecticides, to 5th instar silkworm larvae, examined its residues in hemolymph and midgut of silkworm after continuous exposure to low-dose of acetamiprid, and investigated the transcription level of detoxifying-related genes and the activity of detoxifying enzymes. The results showed that acetamiprid was highly toxic (24-h LC, 1.50 mg/L) to silkworm larvae. After continuous exposure to low-dose of acetamiprid (0.15 mg/L), the acetamiprid residue concentrations in hemolymph and midgut were 0.90 and 0.58 μg/mg, respectively, at 48 h, but all decreased at 96 h. At 24 h of acetamiprid exposure, the transcription levels of CYP4M5 and CYP6AB4 and the P450 enzyme activity were significantly enhanced. However, the transcription levels of CarE and CarE-11 and the activity of CarE enzymes were both inhibited by acetamiprid exposure. After 24 h-72 h of acetamiprid exposure, the transcription levels of GSTe3 and GSTd1 were significantly up-regulated, and the GST enzyme activity was also significantly elevated from 48 h to 96 h. Furthermore, the expression levels of FoxO, CncC and Keap1, the key upstream genes of detoxification enzymes, showed a similar trend as the GST genes. These results indicated that acetamiprid was reduced in midgut and the expression of GSTs was upregulated may via FoxO/CncC/Keap1 signaling pathway, which plays a key role in detoxification responses.
家蚕是一种重要的经济昆虫。然而，由于新烟碱类杀虫剂的广泛使用，造成了环境污染，这极大地影响了蚕桑业的安全生产。本文测定了新烟碱类杀虫剂之一的乙酰甲胺磷对 5 龄家蚕幼虫的半数致死浓度（LC），检测了连续低剂量暴露乙酰甲胺磷后家蚕幼虫血液和中肠的残留量，以及解毒相关基因的转录水平和解毒酶的活性。结果表明，乙酰甲胺磷对家蚕幼虫具有高毒性（24-h LC，1.50mg/L）。连续低剂量暴露乙酰甲胺磷（0.15mg/L）后，48h 时血液和中肠中的乙酰甲胺磷残留量分别为 0.90μg/mg 和 0.58μg/mg，但在 96h 时均下降。暴露乙酰甲胺磷 24h 时，CYP4M5 和 CYP6AB4 的转录水平和 P450 酶活性显著增强。然而，CarE 和 CarE-11 的转录水平和 CarE 酶的活性均受到乙酰甲胺磷的抑制。暴露乙酰甲胺磷 24h-72h 后，GSTe3 和 GSTd1 的转录水平显著上调，GST 酶活性也从 48h 到 96h 显著升高。此外，解毒酶的关键上游基因 FoxO、CncC 和 Keap1 的表达水平与 GST 基因相似。这些结果表明，乙酰甲胺磷在中肠中的含量降低，GSTs 的表达上调可能是通过 FoxO/CncC/Keap1 信号通路实现的，该通路在解毒反应中起关键作用。
