Ultrastructural damage of in vitro cultured ookinetes of Plasmodium gallinaceum (Brumpt) by purified proteinases of susceptible Aedes aegypti (L.).

Previous in vivo studies have implicated trypsin-like proteinases in the destruction of ookinetes of Plasmodium gallinaceum in the gut of the susceptible mosquito Aedes aegypti (Gass 1977). An in vitro study has shown that the ookinetes are destroyed by crude extracts of blood-fed A. aegypti and that this destruction is largely inhibited by an inhibitor of mosquito proteinases, lima bean trypsin inhibitor (Gass and Yeates 1979). In the present study ookinetes of P. gallinaceum have been incubated with highly purified preparations of the three principal trypsin-like proteinases of A. aegypti. It is shown that all three enzymes destroy the ookinetes and that the purified preparations are about as active as crude mosquito extracts.