Figure 2. Concentration-dependent effects of H₂O₂ on (A) cytosolic pH (pH_i) and (B) [ATP]_I in isolated parasites.

Isolated 3D7 P. falciparum trophozoites were loaded with the pH-sensitive fluorescent dye BCECF. H₂O₂ was either absent (black circles) or added at time-zero at a concentration of either 2 mM (triangles) or 10 mM (open circles). The data are averaged from three separate experiments. In (A) the error bars were omitted for clarity; in the control experiment the S.E.M. ranged from 0.003–0.013 pH units, in the 2 mM H₂O₂ experiment the S.E.M. ranged from 0.003–0.092 pH units, and in the 10 mM H₂O₂ experiment the S.E.M. ranged from 0.008–0.109 pH units. In (B) the error bars denote S.E.M.