Fine structure and permeability of peritrophic membranes of Calliphora erythrocephala (Meigen) (Insecta: Diptera) after inhibition of chitin and protein synthesis

Abstract 1. 1. Three tube-like peritrophic membranes are secreted in the anterior part of the midgut of adult Calliphora erythrocephala Mg. (Insecta, Diptera). 2. 2. Inhibition of protein synthesis with cycloheximide resulted in a disturbed formation of these peritrophic membranes. 3. 3. Altered parts permitted the passage of fluorescence-labelled dextrans with higher molecular weight than in untreated flies. 4. 4. Inhibition of chitin synthesis by Polyoxin D, Dimilin, and Captan and of the formation of chitin-containing microfibrils by Calcoflour resulted in a more pronounced enhancement of permeability. 5. 5. Reduction of the chitin content may destabilize the protein moiety. 6. 6. This destabilization is more efficient on permeability than a direct inhibition of protein synthesis.