家蚕围食膜更新过程中的结构变化及与相关酶活性的关系

Structural Changes and Its Relationship with Activity of Related Enzymes in Silkworm Peritrophic Membrane During Regeneration

以家蚕4眠蜕皮前后的幼虫及眠蚕为材料,通过扫描电镜观察及几丁质代谢相关酶活性测定,探讨家蚕围食膜在更新过程中的形态结构和相关酶活性的动态变化。结果显示,4眠蚕围食膜的内表面形态随着入眠程度加深逐渐由完整平滑变为不完整粗糙,且在4眠24 h最为显著;几丁质酶、β-N-乙酰葡糖胺糖苷酶和几丁质脱乙酰化酶在眠期活性显著升高,协同降解围食膜中的几丁质,且几丁质脱乙酰化酶发挥作用较早;海藻糖酶活性在4眠24 h和第4次刚蜕皮时显著升高,说明在旧的围食膜降解旺盛的阶段,新的围食膜也在迅速形成,约在蜕皮后10 h,围食膜就基本恢复完整结构。

Taking silkworm larvae before and after the 4 th molting as materials,morphological structure of silkworm peritrophic membrane during the regeneration process were observed by scanning electron microscopy and chitin metabolism-related enzyme activity was determined.The results showed that inner surface morphology of peritrophic membrane gradually changed from smooth intact to rough incompletion with molting process,and the change was most significant at 24 h post the 4 th molting.Chitinase,β-N-acetylglucosaminidase and chitin deacetylase turned out to be more active during molting,which helped synergistic degradation of chitin in peritrophic membrane,and chitin deacetylase functioned earlier.Trehalase activity significantly increased at 24 h post the 4 th molting and 4 th exuviation,indicating that new peritrophic membrane rapidly formed into shape with degradation of old peritrophic membrane.It was at 10 h post ecdysis when complete structure of peritrophic membrane was basically formed.