AN EXAMINATION OF CUTICLE CHITIN AND PROTEIN IN CYROMAZINE-AFFECTED MANDUCA-SEXTA LARVAE

Effects of cyromazine (2-cyclopropylamino-4,6-diamino-s-triazine) on cuticle chitin and protein were examined using fifth instar Manduca sexta larvae. Cyromazine had no effect on the rate of incorporation of N-acetyl-d-[1-14C]glucosamine into chitin in vitro or in vivo. Cuticle protein levels and incorporation of [2-3H]glycine were reduced in treated larvae compared to controls; however, this was entirely accounted for by the reduced amount of growth during the experimental period. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed no differences in the pattern of cuticle proteins from treated and control larvae and also no differences in proteins synthesized from [2-3H]glycine injected during a period feeding on control or a cyromazine-treated diet. Cyromazine accumulated rapidly in an unchanged form in the cuticle of treated larvae, but was not crosslinked. © 1991.