Premium
The origin and functions of the insect peritrophic membrane and peritrophic gel
Author(s) -
Terra Walter R.
Publication year - 2001
Publication title -
archives of insect biochemistry and physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.576
H-Index - 66
eISSN - 1520-6327
pISSN - 0739-4462
DOI - 10.1002/arch.1036
Subject(s) - midgut , chitin , biology , insect , chitinase , ultrastructure , microbiology and biotechnology , mucus , compartmentalization (fire protection) , biochemistry , enzyme , anatomy , botany , larva , ecology , chitosan
There is a a fluid (peritrophic gel) or membranous (peritrophic membrane, PM) film surrounding the food bolus in most insects. The PM is composed of chitin and proteins, of which peritrophins are the most important. It is proposed here that, during evolution, midgut cells initially synthesized chitin and peritrophins derived from mucins by acquiring chitin‐binding domains, thus permitting the formation of PM. Since PM compartmentalizes the midgut, new physiological roles were added to those of the ancestral mucus (protection against abrasion and microorganism invasion). These new roles are reviewed in the light of data on PM permeability and on enzyme compartmentalization, fluid fluxes, and ultrastructure of the midgut. The importance of the new roles in relation to those of protection is evaluated from data obtained with insects having disrupted PM. Finally, there is growing evidence suggesting that a peritrophic gel occurs when a highly permeable peritrophic structure is necessary or when chitin‐binding molecules or chitinase are present in food. Arch. Insect Biochem. Physiol. 47:47–61, 2001. © 2001 Wiley‐Liss, Inc.