Fig 8. Determination of resistance levels to metals, iron depletion and iron repletion conditions.

Plate sensitivity assays were performed to determine the resistance levels of P. aeruginosa PAO1 and fprB mutant harboring empty vector (pBBR), pFprB, or pISC strains against iron-chelating agent 2,2’-dipyridyl (DIPY, 1.2 mM), ferric iron (FeCl₃, 5.5 mM), copper (CuCl₂, 4.2 mM), cobalt (CoCl₂, 0.5 mM), cadmium (CdCl₂, 0.8 mM), zinc (ZnCl₂, 5 mM), nickel (NiCl₂, 2.5 mM), and magnesium (MgCl₂, 15 mM). The data shown are the means and SD of percent survival at 18 h incubation from three independent experiments. The asterisk indicates a statistically significant difference (P < 0.01) between the two indicated strains.