Figure 4

Rac1 functional analysis. (A) Histogram showing the G-LISA test results of erythrocytes treated with the Rac1 inhibitors EHT1864 and 1A116, as a percentage of the untreated control. Student’s T-test with both inhibitors: P < 0.05. (B) Growth curves for IC₅₀ determinations. (C) P. falciparum invasion rates in the presence of the Rac1 inhibitors EHT1864 and 1A116. The number of newly infected erythrocytes at the end of the assay was normalized on the control. Data shown here are the result of three independent experiments, each performed in three technical replicates. Student’s T-test: NS: non-significant; * =  P < 0.05; **  < 0.01; *** ≤ 0.005. (D) Effect of Rac1 chemical inhibitors on P. falciparum intraerythrocytic growth. Blood smears of a synchronous parasite culture were taken at 39 hpi, corresponding to almost mature schizont stages. Parasitemia was normalized on the control. Data shown for EHT1864 are the result of three independent biological replicates, while for 1A116 the data are the result of two biological replicates. Student’s T-test: P < 0.05 with both inhibitors. (E) Giemsa-stained smears of synchronous P. falciparum parasites at 39 hpi, treated with the Rac1 chemical inhibitors EHT1864 and 1A116. Arrows point at possible residues after parasite death. Scale bar: 20 µm. F. Histogram showing parasite cell areas in the inhibitor-treated samples, normalized on the untreated control. These data are the result of two biological replicates. Student’s T-test: P < 0.05 with both inhibitors.