FIGURE 3.

Growth of moderately copper sensitive AB5075 mutant and complementation strains. Strains were grown for 6 h at 37°C in M9 medium supplemented with the concentration of CuSO₄ indicated in the legend. Growth was measured both by turbidity (OD₆₀₀, data not shown) and enumeration of viable colonies (CFU/mL). Black lines are used to group the mutant strain with the corresponding complemented derivative. The data are presented as geometric mean and SEM of three biologically independent experiments. Two-way ANOVA with Tukey’s adjustment for multiple comparisons was used to compare growth in each copper concentration at each timepoint. The symbols indicate which copper treatments were statistically different (P < 0.05) from the 0 mM control, as follows: ∼, growth in 1.5 mM CuSO₄ was different from the control; +, growth in 1 and 1.5 mM CuSO₄ was different from the control.