Proguanil

Experiments reported in this study were performed using P. falciparum parasite strains Dd2 (86 (link)) and NF54 (87 (link)). The identities of these strains were confirmed by their expected drug-sensitivity profiles and were Mycoplasma-free by PCR test. Parasite culturing was done in Roswell Park Memorial Institute medium (RPM1-1640, Thermo Fisher 23400021) supplemented with 2.5 g/L Albumax I Lipid-Rich BSA (Thermo Fisher 11020039), 15 mg/L hypoxanthine (Sigma H9636), 110 mg/L sodium pyruvate (Sigma P5280), 1.19 g/L HEPES (Sigma H4034), 2.52 g/L sodium bicarbonate (Sigma S5761), 2 g/L glucose (Sigma G7021), and 10 mg/L gentamicin (Invitrogen Life Technologies 15750060). Parasite cultures were maintained at 2% hematocrit in deidentified human erythrocytes obtained from the University of Utah Hospital blood bank, at 37°C, and at 5% O₂, 5% CO₂, 90% N₂. For growth assays with decyl-ubiquinone (dQ, Caymen Chemicals 55486005) and/or proguanil (Sigma 637321), the growth medium was supplemented with 15 µM dQ (DMSO) and/or 1 µM proguanil (DMSO), final concentration. In all cases, the final DMSO concentration was limited to ≤0.3% w/v.