Temporal synthesis of cuticle proteins during larval development in the tsetse fly, glossina morsitans morsitans
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Date
1992Author
Ochieng, Vincent O
Type
ThesisLanguage
enMetadata
Show full item recordAbstract
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, as 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.
Further analysis by two-dimensional gel electrophoresis and silver
staining showed that few cuticular proteins were synthesized between the 18t
and z- instars. By third instar (2 days before larviposition), a large number of
proteins were induced (M, < 30 KD). These proteins persisted upto the brown
pupal stage and showed a rapid decline thereafter. Most of the proteins with
molecular weights Mr < 30 KD were undetectable at apolysis (5 days after
larviposition). By 15 days pupal stage, the number of cuticle proteins was very
small. Ligation of adults at eclosion resulted in notable changes of cuticle
proteins.
Citation
Master of SciencePublisher
University of Nairobi