麻疯树萜醇I对家蚕的毒性及作用机理研究

研究了从麻疯树种子中分离的麻疯树萜醇I对3龄家蚕的毒性及其对家蚕中肠蛋白酶和组织结构的影响。结果显示:麻疯树萜醇I对家蚕无接触毒性,其急性毒性主要表现为胃毒作用,处理后48、72和120 h的LC50值分别为0.579、0.220和0.158 mg/mL。家蚕对麻疯树萜醇I处理 叶片的取食量显著少于对照组,24 h和 48 h的拒食中浓度(AFC50)分别为0.160和0.145 mg/mL。 取食麻疯树萜醇I后,家蚕体重增长显著被抑制,这一抑制作用具有明显的时间效应和浓度效应,即随着处理浓度的增高和处理时间的延长而逐渐增大。取食麻疯树萜醇I还导致家蚕中肠蛋白酶的比活力随时间逐渐下降,48 h时最低,0.25、0.125及0.062 5 mg/mL处理组蛋白酶比活力分别仅为对照的32.94%、43.35%、71.45%;处理浓度越大,蛋白酶比活力越低。石蜡切片显示,麻疯树萜醇I主要影响了中肠细胞的组织结构,引起细胞从基底膜上脱落,细胞破裂,使脂肪体消融等。表明麻疯树萜醇I对消化系统的破坏是其导致试虫中毒的重要机制之一。

Toxicity and Mechanism of Jatropherol I to Silkworm, Bombys mori L.

Jatropherol I(JaI), a diterpene separated from Jatropha curcas seed oil was used to (evaluate) its toxicity to 3rd-instar silkworm, Bombys mori L., as well as its effects on midguts tissue and (proteinases) activity of midguts. The results showed that JaI had no contact toxicity but strong stomach (toxicity) to 3rd-instar silkworm. The LC_(50) value were (0.579),(0.220) and (0.158 mg/mL) (respectively) at 48, 72 and 120 h after ingestion of JaI. JaI had a (significant) antifeedant effect to silkworm with AFC_(50) of (0.160) and 0.145 mg/mL, respectively at 24 h and 48 h. A strong inhibition with obvious dose and time dependent effect was observed in JaI on the growth of silkworm. The (inhibitory) effect of JaI increased with time and concentration increased. After silkworm was fed with JaI treated mulberry leaves, (proteinases) activity in midguts reduced with time increased. The activity of proteinases reached the minimum at 48 h after treatment, which was only 32.94%,43.35%,(71.45%) of the control at 0.25,0.125 and (0.062 5 mg/mL,) respectively. Tissue structure of (midguts) in silkworm exposed to JaI was examined by histological method. Damages in epithelial cells and disintegration of fat body were observed. It was (suggested) that damages to insect digestion system induced by JaI might be an important toxicological mechanism of JaI to silkworm.