Fig. 4. Swim speeds of intact wild-type (CU427.4) and mutant (DYH7neo3) cells. (A) Mutant cells were harvested for analysis from growth media containing paromomycin and cadmium (+ drug) or from growth media in which these selective agents were absent (– drug). Mutant cells consistently displayed swim speeds of almost half those of wild type. (B) Mutant and wild-type cell lines were cultured free of paromomycin and cadmium, and swim speeds were analyzed periodically over a span of 1 month. Mutant cells from standing tube (closed circles) and shaken flask (open circles) culturing methods are compared. Reversion to wild-type phenotype was not observed. The CU427.4 wild-type control cells (closed squares) were cultured in standing tubes. Each bar and data point represents the mean ± s.d. of three trials of 100-cell measurements.