BLOODMEAL DIGESTION IN THE MIDGUT OF PHLEBOTOMUS-PAPATASI AND PHLEBOTOMUS-LANGERONI

Bloodmeal digestion in midguts of the sandflies Phlebotomus papatasi and Phlebotomus langeroni (Diptera: Psychodidae) was investigated in optimized assays to detect general protease, trypsin and aminopeptidase activities using synthetic substrates. Optimal activity occurred at pH 8-9 for all enzymes examined in both species. Protease activity peaked at 24-34 h post human bloodmeal in midguts of P.papatasi and 34-48 h in P. langeroni; all endo- and exoprotease activities were completed by 50 h in P.papatasi compared to 72 h in P.langeroni. Hydrolysis of two chymotrypsin substrates was <2% of trypsin activity in both species. Aminopeptidase activity was associated mainly with the midgut wall, whereas trypsin activity was confined to the midgut lumen. A feature of digestion in P.langeroni was the high level of aminopeptidase recorded within 10 h of the bloodmeal.