FIG 4.

Na⁺ dependence of KAE609-induced swelling of isolated P. falciparum trophozoites. Isolated trophozoites were suspended in Na⁺-, NMDG-, or choline-containing saline for 20 min at 37°C before the addition of either 10 nM KAE609 in DMSO or DMSO alone (solvent control; 0.1% [vol/vol]) (−). The volume of the isolated 3D7 trophozoites was measured immediately prior to the addition of KAE609 or DMSO and then again 15 min later. The percent volume change was determined by comparing the median cell volumes at the beginning and end of the 15-min incubation. The results shown are averaged from those obtained in five independent experiments, and error bars denote SD. The letters above the bars indicate statistical significance, with the bars labeled “a” being not significantly different from one another but significantly different from that labeled “b” (P < 0.05).