Characterization of cuticular proteins in the red flour beetle, Tribolium castaneum

We are characterizing the cuticular proteins of Tribolium castaneum (Herbst ) (Coleoptera: Tenebrionidae) to determine their role in the function of th e exoskeleton. Based on qualitative analyses of cuticles, we focused on the sodium dodecyl sulfate (SDS)extractable proteins. A small-scale cuticle "m ini-prep" procedure was devised that yields preparations virtually free of contaminating cellular material compared to hand-dissected preparations, as assessed by fluorescent microscopy using DAPI to stain nuclei. Proteins ex tracted in 1% SDS from various developmental st:ages (last larval instar, p upal, adult) were analyzed by one-dimensional denaturing polyacrylamide gel electrophoresis and by two-dimensional gel electrophoresis. The cuticular protein profiles show both similarities and differences among the stages ex amined. The amino acid composition, glycosylation, and partial amino acid s equence of several abundant cuticular proteins indicate similarity to cutic ular proteins of other insects. (C) 2000 Elsevier Science Ltd. All rights r eserved.