FIGURE 5.

Cytoplasmic K⁺ pools. Intracellular K⁺ levels in strains grown under AmtB-expressing conditions (Na⁺-based N⁻C⁻ minimal medium supplemented with 0.4% glucose, 3 mm glutamine, and 100 mm KCl). All amtB alleles were carried in the kdp trk kup strain background. For comparison purposes, the cytoplasmic K⁺ pool of the prototrophic E. coli K-12 parental strain NCM3722 (Kdp Trk Kup) (31) is shown (red bar). Values reported are means ± S.D. (error bars) for at least three independent experiments.