FIG. 6.

Copper sensitivities of the M. xanthus WT strain (▪) and the Δcus1 (♦), Δcus2 (▴), and Δcus3 (•) mutants during growth. (A) Copper tolerance of cells not preadapted 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 correspond to the OD₆₀₀ monitored at 24 h of incubation. (B) Copper tolerance of cells adapted to copper. 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 and are the averages of data from three experiments. The error bars indicate standard deviations.