Second, drug-sensitivity assays of various fluoroquinolone compounds also revealed that there may be more than one mode of action of this class of compounds on malaria parasites, one with an apicoplast target (DNA gyrase) sensitive to low micromolar drug concentrations and the other with a nonapicoplast target that required a higher concentration of ciprofloxacin (Fig. 7). Here, TOP2A is linked to malaria.