Wang P, Granados R R
Department of Entomology, Cornell University, Ithaca, New York 14853, USA.
J Invertebr Pathol. 1998 Jul;72(1):57-62. doi: 10.1006/jipa.1998.4759.
Light microscopical examinations of dissected and stained peritrophic membranes (PMs) were conducted to determine the presence or absence of this protective structure in larvae of Trichoplusia ni, prior to and through ecdysis. Observations of fourth- and fifth-instar larvae of T. ni from two independent rearing colonies showed that PMs were present and lined the midgut prior to, during, and immediately after ecdysis in both instars. Western blot analysis of insect intestinal mucin (IIM), a major protective protein in the T. ni PM, indicated that synthesis of IIM occurred during T. ni embryonic development, or more precisely, that IIM synthesis started approximately 4 h prior to hatching. These results demonstrated that the neonate T. ni midgut is lined with a protective mucinous layer at hatching. A baculovirus enhancin from T. ni granulosis virus (TnGV) enhanced per os viral infections of budded viruses (BVs) of Autographa californica multiple nuclear polyhedrosis virus (AcMNPV) and T. ni single nuclear polyhedrosis virus (TnSNPV) in neonate, fourth-, and fifth-instar larvae of T. ni. These results provided further evidence that the PM may serve as a partial barrier to viruses in the midgut lumen and that enhancins can facilitate the infection process.
对解剖并染色的围食膜（PMs）进行光学显微镜检查，以确定粉纹夜蛾幼虫在蜕皮前及蜕皮过程中是否存在这种保护结构。对来自两个独立饲养群体的粉纹夜蛾四龄和五龄幼虫的观察表明，在这两个龄期的蜕皮前、蜕皮期间和蜕皮后，围食膜均存在并衬于中肠。对粉纹夜蛾围食膜中的一种主要保护蛋白——昆虫肠道粘蛋白（IIM）进行的蛋白质免疫印迹分析表明，IIM的合成发生在粉纹夜蛾胚胎发育期间，或者更确切地说，IIM合成在孵化前约4小时开始。这些结果表明，刚孵化的粉纹夜蛾中肠内衬有一层保护性粘液层。来自粉纹夜蛾颗粒体病毒（TnGV）的杆状病毒增强蛋白增强了苜蓿银纹夜蛾多核多角体病毒（AcMNPV）和粉纹夜蛾单核多角体病毒（TnSNPV）的芽生病毒（BVs）对粉纹夜蛾新生幼虫、四龄和五龄幼虫的经口病毒感染。这些结果进一步证明，围食膜可能作为中肠腔中病毒的部分屏障，且增强蛋白可促进感染过程。
