FIG. 3.

Time dependence of G25-induced growth arrest at the ring, trophozoite, and schizont stages. Cells were synchronized with 5% d-sorbitol at −82, −43, and −1 h (0.5% initial parasitemia, 1.5% hematocrit, Nigerian strain). Ring, trophozoite, and schizont stage parasites, which were obtained at time zero and 24 and 36 h, respectively, were exposed to 20 nM G25 for the indicated period of time, and then the drug was removed, as described in Materials and Methods. Parasites were labeled with [³H]hypoxanthine at 52 h (the parasitemia in control experiments was 2.2%) until 72 h. Hypoxanthine incorporation is expressed as a percentage of the control (without drug) for the ring (R), trophozoite (T), and schizont (S) stage parasites.