Fig. 2.

Regulation of expression of a zupT-lacZ reporter gene fusion. Cells of C. metallidurans AE104 carrying a zupT-lacZ fusion were incubated in TMM containing various concentrations of the chelating substance DPTA (▴), EDTA (•), or phosphate (▪) (A); zinc in the AE104 parent (•) or the ΔpitA (○), ΔcorA₂ (□), or ΔcorA₃ (▵) mutant (B); increasing concentrations of the chelating substance TPEN in the presence of 20 μM Fe³⁺ (♦), Mn²⁺ (▴), Co²⁺ (▪), or Zn²⁺ (•) or without added metal cations (○) (C); or increasing concentrations of EDTA-metal complexes in a 1:1 ratio, i.e., no metal (○), Zn²⁺ (•), Co²⁺ (▪), Mn²⁺ (▴), or Ni²⁺ (▾) (D). Incubation was continued for 16 h (phosphate) or 3 h (all others), and the β-galactosidase activity was determined. At least three independent determinations were made. Error bars indicating standard deviations are shown in panels A and B, but not in panels C and D to avoid cluttering. d.w., dry mass. Note that only panel B has a linear x axis.