FIG 6.

Effects of KAE609 and other compounds on the volume of intact parasitized erythrocytes. (a) Time courses (measured at 37°C) for the volume of parasitized erythrocytes (parasitemia of ≥95%; cells were suspended in bicarbonate-free supplemented RPMI 1640 medium) following the addition of 10 nM KAE609 (in DMSO) (black circles), 100 nM chloroquine (in DMSO) (gray circles), or DMSO alone (0.1% [vol/vol]; solvent control) (white circles). In each case, a first-order exponential equation was fitted to the data. The data shown are averaged from those obtained in five independent experiments, and the error bars denote SD. (b) Volume changes (expressed as percentages of the initial volume) of parasitized erythrocytes (parasitemia of ≥95%) and cohort uninfected erythrocytes (uRBC) incubated for 60 min in the presence and absence of various PfATP4-associated compounds or unrelated antimalarials (artemisinin and chloroquine). The results shown are averaged from those obtained in at least three independent experiments, and error bars denote SD. The compound concentrations used were the same as those described in the legend to Fig. 3. The letters above the bars indicate statistical significance. Bars labeled with the same letter are not statistically different from one another (P > 0.05), whereas those labeled with different letters are significantly different from one another (P < 0.05).