THE EFFECT OF PLASMODIUM-YOELII NIGERIENSIS INFECTION ON OVARIAN PROTEIN ACCUMULATION BY ANOPHELES-STEPHENSI

Both anopheline and culicine mosquitoes have been shown to incur a red uction in reproductive fitness when infected with malaria parasites. T he agent of rodent malaria, Plasmodium yoelii nigeriensis, was used as a laboratory model to investigate changes in the accumulation of prot ein in the ovaries of Anopheles stephensi when infected with oocysts o r when feeding on mice with heavy asexual parasitaemia but no mature g ametocytes. Herein we report that during the early phases of the gonot rophic cycle the ovarian protein content increased normally; however, after 16 h post-blood-feeding there was a significant reduction in the total protein content in ovaries from infected mosquitoes. The develo pment of ovaries from mosquitoes undergoing a second gonotrophic cycle and containing maturing oocysts was similarly affected. Ovarian prote in profiles produced by sodium dodecyl sulfate-polyacrylamide gel elec trophoresis showed a depletion of the yolk protein vitellin. Ovaries f rom mosquitoes feeding on a mouse with 31% parasitaemia, no detectable gametocytes and a low haematocrit (29% packed cell volume) also exhib ited a reduction in protein content, although this did not occur until much later in the gonotrophic cycle. The role of blood-meal quality a nd malaria infection in the reduction in egg production is discussed.