【作者】 相静波；

【导师】 刘惠霞；

【作者基本信息】 西北农林科技大学 ， 农业昆虫与害虫防治， 2004， 硕士

【摘要】 苦皮藤素Ⅴ是从苦皮藤植物根皮中分离的一种对昆虫具有毒杀活性的化合物，可对不同昆虫表现出不同的选择毒性。围食膜是大多数昆虫中肠细胞分泌的一层非细胞性薄膜，具有多种功能。本文采用扫描电镜、透射电镜、SDS-PAGE 及生化分析等方法研究了东方粘虫和小地老虎幼虫围食膜组分、结构及与苦皮藤素Ⅴ选择毒性关系，结果表明：　小地老虎围食膜中糖含量约 4.84μｇ·ｍＬ－１，蛋白质约 21.72μｇ·ｍＬ－１；东方粘虫围食膜中糖含量约 3.50μｇ·ｍＬ－１，蛋白质约 24.07μｇ·ｍＬ－１。其中小地老虎围食膜糖含量显著高于东方粘虫，而蛋白质含量低于东方粘虫；东方粘虫和小地老虎幼虫围食膜蛋白组分中蛋白质种类很多，都由十几种多肽组成。但两种试虫的围食膜蛋白组分存在差异。小地老虎和东方粘虫幼虫的围食膜都呈多层结构，比较明显的有三层，分别是粗糙层，微纤维层和精密层。小地老虎围食膜几丁质微纤丝网格的排列紧密，结构致密、并具有分布密集、整齐的糖链结构；而东方粘虫围食膜几丁质纤丝排列比较粗糙，网格孔洞较大，电子致密物显著多于小地老虎，并未见明显的糖链结构。苦皮藤素Ⅴ处理后，小地老虎幼虫围食膜糖链减少、排列稀疏，但较规则；东方粘虫围食膜结构紊乱、不完整，电子致密物减少；两种试虫的围食膜的局部区域网格结构排列密集，并从原来的规则形状变成不规则排列。但苦皮藤素Ⅴ处理后，对围食膜蛋白组分影响较小，仅有少部分发生解离。　以上结果表明：两种试虫围食膜组分及结构的差异可能是苦皮藤素Ⅴ选择毒性的机制之一。更多还原

【Abstract】 Celangulin Ⅴisolated from the root bark of chinese bittersweet (Celastrus angulatusMaxim.) is a new insecticidal compound,and has selective toxicity against different insects. Peritrophic membrane (PM) is secreted by midgut cell and separates the food from themidgut epithelium in most but not all insects and it plays key roles in the intestinal biology ofthe insect.By means of scanning electron microscopy (SEM),transmission electronmicroscopy (TEM)，SDS-PAGE and biochemistry analysis, studies on the components andstructure of PM of Mythimna separata and Agrotis ypsilon larvae,and the relationshipbetween the structure and components of PM and selective toxicity of Celangulin Ⅴ hasbeen carried out.The mains results are as follows: The peritrophic membrane protein content of M. separata and A. ypsilon was24.07μg·mL-1 and 21.72μg·mL-1, the carbohydrate content of the peritrophic membrane was3.50μg·mL-1 and 4.84μg·mL-1 ,respectively. Compared with M. separata,the carbohydratecontent of PM of A. ypsilon was higher, but the protein content was lower. SDS-PAGE results indicated there were many kinds of protein in PM,but the componentsof the protein in two species was different.In the same species, PM protein components hadno markedly difference between the controland treated group. TEM results exhibited PM had many layers，obviously there were three layers: coarselayer,microfibre layer and precision layer. In lavae of A. ypsilon the structure was tight andthick,glycosylation chains were regular and concentrative, chitin microfibrils were regularlyarranged to form a network embedded in an amorphous matrix.While in M. separata ,glycosylation chains were invisible,chitin microfibrils arranged sparsely ,and pores wereapparent.The electronic density of PM of M. separata is higher than A. ypsilon. Treated by Celangulin Ⅴ, the structure of A. ypsilon was changed, the glycosylationchains were shottened,sparsed and irregularly.The structure of M. separata was imcomplete,sparsed and irregularly arranged,the electronic particles was shottened. The permeability ofthe PM of M. separata was better than that of A. ypsilon. Celangulin Ⅴ had a little effect onPM protein,and small amount of polytides was dissolved. All these results showed the difference of PM structure and components might be themechanisms of selective toxicity of Celangulin Ⅴ against the lavae of A. ypsilon and M.separata.更多还原