Temporal Synthesis of Cuticle Proteins During Larval Development in the Tsetse Fly, Glossina Morsitans Morsitans

Abstract

The tsetse fly is an insect of great economic importance to man as a vector of both human and animal trypanosomiasis. The important functions of the cuticle are support, including muscle attachment, protection, and permeability barriers. Cuticle proteins are an important component, that define much of specialized structural and functional nature of the cuticle. A thorough knowledge of the patterns of cuticle proteins during larval development in G. m.morsitans is important in understanding their possible roles in cuticular sclerotization. Such knowledge might be useful in management of tsetse flies. In this study proteins extracted from larval, pupal and adult cuticles of the tsetse fly, Glossina morsitans morsitans were compared electrophoretically by both SDS polyacrylamide gel electrophoresis and two dimensional gel electrophoresis. Proteins extracted from the third instar resolved into ten major bands (Mr 10 KD, 12 KD, 14 KD, 26 KD, 28 KD, 38 KD, 45 KD, 70 KD, 93 KD, 112 KD, 200 KD). In SDS-PAGE, two major proteins (45 KD and 200 KD) were common to all stages of development. The 45 KD had a carbohydrate moiety as it stained with Periodic acid schiff reagent (PAS). Cuticles from three larval instars (first, second and third) contained six low molecular weight proteins (10 KD, 12 KD, 14 KD, 30 KD, 50 KD, 80 KD). Two proteins emerging in pupal cuticle (29 KD and 98 KD) persisted upto the adult stages.