Figure 7.

Mutation and repair kinetics in arrested cell cultures induced to proliferate. The frequency (±SD) of bacterial (●) and cellular (■) lacI mutations in quiescent cultures (12 days after serum removal) treated with ENU (400 μg/ml) in serum-free medium for 30 min at standard cell culture conditions. Quiescent cells (red) were induced to proliferate 4 days posttreatment (green). Mutation frequencies less than zero arise when an observed value in the treated group is less than that in the controls.