An antimicrobial peptide with trypanocidal activity characterized from Glossina morsitans morsitans

Tsetse flies (Diptera:Glossinidae) are vectors of African trypanosomes. the protozoan agents of devastating diseases in humans and animals. Prior studies in trypanosome infected Glossina morsitans morsitans have shown induced expression and synthesis of several antimicrobial peptides in fat body tissue. Here, we have expressed one of these peptides, Attacin (GmAttAl) in Drosophila (S2) cells in vitro. We show that the purified recombinant protein (recGmAttAl) has strong antimicrobial activity against Escherichia coli-K12. but not against the enteric gram-negative symbiont of tsetse, Sodalis glossinidius. The recGmAttAl also demonstrated inhibitory effects against both the mammalian bloodstream form and the insect stage Trypanosoma brucei in vitro (minimal inhibitory concentration MIC50 0.075 muM). When blood meals were supplemented with purified recGmAttAl during the Course of parasite infection, the prevalence or trypanosome infections in tsetse midgut was significantly reduced. Feeding fertile females GmAttAl did not affect the fecundity or the longevity of mothers, nor did it affect the hatchability of their offspring. We discuss a paratransgenic strategy, which involves the expression of trypanocidal molecules such as recGmAttAl in the midgut symbiont Sodalis in vivo to reduce trypanosome transmission. (C) 2004 Elsevier Ltd. All rights reserved.