Peritrophic Envelope: A Non-Cellular Envelope of Midgut in Insects

Abstract

There is a fluid film surrounding the food bolus in most insects which is known as peritrophic envelope. The peritrophic envelope is composed of chitin and proteins, of which peritrophins proteins are the most important composition. Since peritrophic envelope is differentiated into two compartments in the midgut, which adds new physiological roles. These new roles are observed on envelope permeability and on enzyme compartmentalization, fluid fluxes, and ultrastructure of the midgut. Insects lacking peritrophic envelope have a special structure called perimicrovillar membrane. Moreover the function of peritrophic envelope provides barrier against various pathogens in other way it can be called that it provides immunity to various viral diseases too.