FIG. 2.

(A) Sensitivity to Dipy (Dipy). NTL4/pBBR and NTLfur/pBBR strains are the wild type and the fur mutant, respectively, containing the plasmid vector pBBR1MCS-4. NTL4/pFur and NTLfur/pFur strains are the wild type and the fur mutant, respectively, expressing functional Fur from the plasmid pFur. Cells were grown under iron-sufficient (LB) and iron-limiting (LB + 300 μM Dipy) conditions. Growth was monitored by measuring the OD₆₀₀ after incubation at 28°C with shaking for 24 h. The values presented are means, and the error bars indicate the standard deviations of three replicates. (B) Sensitivity to SNG. Cells were untreated and treated with 100 μg ml⁻¹ of SNG at 28°C for 24 h. Cells were diluted and spotted on LB agar plates. Tenfold serial dilutions are marked above each column. (C) Effect of addition of metal ions to the growth in the presence of Dipy. Cells were diluted and spotted onto LB agar plates containing 300 μM Dipy and 100 μM concentrations of either FeCl₃, MnCl₂, ZnCl₂, or CuSO₄ and then incubated at 28°C for 48 h. Cells spotted onto an LB agar plate (LA) were used as a control.