The in vitro cultivation of P. falciparum ookinetes, and their enrichment on Nycodenz density gradients.

Employing a simple method of growing ookinetes of Plasmodium falciparum in culture, 40% of mature gametocytes convert to macrogametes, 4% reach the retort-form ookinete stage and 0.45% become mature ookinetes. A single-step gradient centrifugation method on 12.5% Nycodenz enriches both gametocytes and ookinetes.

Ookinete antigens of Plasmodium berghei: a light and electron-microscope immunogold study of expression of the 21 kDa determinant recognized by a transmission-blocking antibody.

The expression of a 21 kDa transmission-blocking determinant on the malarial parasite Plasmodium berghei was studied by using the immunogold method at the light, scanning-electron and transmission-electron microscope levels. The determinant was shown to be expressed exclusively on the macrogamete and its immediate progeny the zygote, ookinete and oocyst. It is first detected on the plasmalemma two hours after the escape of the parasite from the red blood cell, reaches a maximal density on the young ookinete some ten hours later, and is still found on the oocyst after six days. The antigen is distributed evenly over the entire surface of the zygote and ookinete, but is readily shed from the parasite surface. The general applicability of the silver-enhanced immunogold method in parasitological research is emphasized.