FIG. 9.

(A) Sensitivity of various strains of E. coli to nickel. Strains were normalized to the same OD₆₀₀ and inoculated in triplicate into M9/gluconate minimal medium with increasing levels of NiCl₂. Final growth was recorded after 24 h at 37°C. (B) Overnight cultures of various strains of E. coli were normalized to the same OD₆₀₀ and spotted on LB agar plates containing 1 mM NiCl₂. Final growth was recorded after 14 h at 37°C. The ΔyqjH* strain contains unknown secondary mutations that suppress the ΔyqjH phenotype and render it nickel resistant.