Production of ¹⁴C-CO₂ is expressed as μmol/10¹⁰ cells/hour at 37°C. Mean values ± SD of 3 of 18 separate experiments (n) as indicated. RPE were separated from synchronized P falciparum cultures as detailed in Materials and Methods 14 to 18 hours after inoculum. ¹⁴C-CO₂production values obtained with cultures containing 30% to 45% RPE were extrapolated to 100% RPE parasitemia as indicated in Materials and Methods. Nonparasitized E (NPE) were kept in culture and processed in the same way as parasitized E. MB, 135 μmol/L final, was used to maximally stimulate ¹⁴C-CO₂ production. Column D-B: net maximal ¹⁴C-CO₂ production by RPE after MB stimulation (see Results for details). P→ = significance to the first column to the right;P→→ = significance to the second column to the right; P↓ = significance within the same column. Significance of differences was assessed by t-test for paired samples.