FIG. 3.

Copper sensitivity of the M. xanthus WT strain (black lines) and the ΔcopA (blue lines), ΔcopB (red lines), and ΔcopC (green lines) mutants during growth. (A) Copper tolerance of nonpreadapted cells to the metal. Cells grown in the absence of copper were diluted to an OD₆₀₀ of 0.05 in fresh CTT liquid medium containing the indicated copper concentrations. The data shown indicate the OD₆₀₀ monitored after 24 h of incubation. (B) Copper tolerance of cells adapted to copper. The strains were grown in the presence of 300 μM copper prior to dilution into fresh CTT liquid medium containing different copper concentrations. The data are expressed as mentioned above for A. Data are the averages of data from three experiments. The error bars indicate standard deviations.