Fig. 5. Wild-type (CU427.4) and mutant (DYH7neo3) cells modulate their swim speed under the addition and removal of 8 mM KCl. (A) Mutant cells were harvested for swim speed analysis from growth media containing paromomycin and cadmium (+ drug) or from growth media in which these selective agents were absent (– drug). Despite their reduced basal swim speed relative to wild type, mutant cell lines are able to further decrease their swim speed under 8 mM KCl depolarizing stimulus in a way that mirrors that of wild type. (B) Swimming behavior was examined as cells were introduced to a range of KCl concentrations. Beyond 10 mM, cells began to display constant ciliary reversal behavior (CCR). Mutant cell lines cultured in the presence of selective agents (open circles) and the absence of selective agents (closed circles) retained their ability to display ciliary reversal with a concentration dependency similar to that of CU427.4 (closed squares). Each bar and data point represents the mean ± s.d. of three trials of 100-cell measurements.