FIG 2.

PPQ dose-response curves for 3 illustrative P. falciparum isolates that were not cleared at the maximum PPQ concentration used in the original assay. The colors denote different isolates. The solid lines are growth inhibition curves interpolated by HRP-2 OD, as measured by serial PPQ dilution with concentrations ranging from 0 to 674 nM. The dashed lines represent reanalyzed curves by including the control OD value for 100% HRP-2 inhibition (2,000 ng/ml CQ) and refitting the curve. This was equivalent to a concentration of 53,905 nM PPQ (denoted by closed circles); reinterpolated IC₅₀s using these values are denoted by vertical colored lines for each isolate.