Purification and properties of the low molecular weight protein from haemolymph of the tsetse fly, glossina morsitans morsitans

Abstract

Tsetse fly is an insect of great economic importance to man because it transmits sleeping sickness to both man and his livestock. The insect feeds on a bloodmeal thereby transmitting the disease from infected to healthy individuals. The tsetse fly, Glossina spp. belongs to the order Diptera and family Glossinidae and 22 species have been identified. The fly is mainly found in humid areas especially along the river valleys and bushes in Sub-Saharan Af~ica. Insects are known to posses haemolymph as the circulatory fluid equivalent to blood and lymph in vertebrates. In both cases, the circulating fluids have been shown to contain lipoproteins as the major component. Various haemolymph proteins serving a wide range of functions haVe been described in many insect species. Whereas some of these proteins have been well studied in some insect species, the same has not been done in the tsetse fly despite its great economic importance. This study therefore, investigates the properties of a low molecular weight protein isolated from haemolymph of adult male G.~ morsitans. The protein was purified from haemolymph by a combination of density gradient ultracentrifugation and gel permeation -, chromatography. The protein has a molecular weight of 23,000 dalton as determined by electrophoresis on polyacrylamide gels.