FIG. 5.

Phenotypes of A. tumefaciens cop mutants. (A) The levels of resistance to Cu ions were determined using plate sensitivity assays. A. tumefaciens strains were plated onto medium containing 5 mM CuSO₄. Percent survival was determined by the number of CFU on LB agar plates containing CuSO₄ divided by the number of CFU on LB agar plates multiplied by 100. (B) The Cu requirements of A. tumefaciens wild-type strain NTL4 (open circles) and the copA operon mutant (closed circles) were determined by growth in AB minimal medium supplemented with the Cu(II) chelator cuprizone. Bacterial growth was determined by measuring the optical density at 600 nm (OD₆₀₀) after 30 h of incubation. (C) The levels of resistance to oxidants were determined as described above (A), but oxidants were added instead of metal ions. NTL4 (gray shaded bars) and copA operon mutant strain (open bars) cultures were plated onto medium containing 500 μM MD, 100 μM PB, or 300 μM H₂O₂. Error bars indicate the SD of data from four independently performed experiments.