Research On The Development Of Peritrophic Membrane And Its Molecular Detection Of Helicoverpa Armigera

Peritrophic membrane (PM) is a selective permeability membrane lining the midgut lumen widely in many insects, having the functions of increasing intestinal lubrication, facilitating food digestion, inactivating toxins, and it also plays an important role as a physical barrier in protecting the midgut epithelial cells from abrasive food particles and pathogens for it’s special position between food bolus and midgut epithelium.For the purpose of observing the presence or absence of PM in different developmental stages in Helicoverpa armigera, and studying the influence caused by lack of food on PM, these experiments were conducted as followed: Peritrophic membrane was dissected from the fifth-instar H.ar larvae, rinsed to Colorless transparent in Rinaldini’s solution, homogenated in 100μl of SDS-PAGE sample buffer and boiled for 5min. After centrifugation, supernate was used to immunize a rabbit to generate the antiserum. Dissection, Congo red staining, Western blot and RT-PCR were used in this experiment to detect the PM protein expression in different developmental stages of H.ar, such as eggs; newly-hatched larvae; larvae prior to, during and immediately after Ecdysis from fourth- to fifth-instar, prepupae, pupae, and adult. Besides, newly-hatched larvae and newly-molted fifth-instar larvae were treated respectively under extremely different food condition, feeding and starvation to study the relationship between PM changes and food supply.The results of PM proteins detection in different developmental stages showed that PM proteins have emerged early in the embryo period and lasted to adult. In other words, PM proteins could be detected in all the different developmental stages. PM could be found during the molting process too, and it seemed to have self renewal in the process. The outcome of RT-PCR showed that HaIIM86 only expressed in midgut and the expression lasted in all the stages from eggs to adults which implied that HaIIM86 could be used as the molecular label to some degrees in the PM detectionThe results of starvation treatments showed that food condition does have influence on PM, however the influence is limited, only with some component and physical characteristics changed. Deprivation of food can not result in the absence of PM.