Figure 7. Effect of KCl on the growth and intracellular ion content of various E. coli TK2420 transformants.

The growth of E. coli strain DH5αMCR transformed with control plasmid pBAD24 (filled blue circles) and E. coli strain TK2420 transformed with pBAD24 (open blue circles), pBAPS (filled red circles) and pBAPS-MotS_M33L (open red circles). Cells were shaken in the TK2420 minimal medium adding 10 mM (A), 25 mM (B) or 50 mM (C) KCl at 37°C under aerobic conditions. Cell growth was monitored at 600 nm. Intracellular [K⁺] and [Na⁺] levels in E. coli DH5αMCR transformed with control plasmid pBAD24 (filled light blue bar) and E. coli strain TK2420 transformed with pBAD24 (open light blue filled bar), pBAPS (filled red bar) and pBAPS-MotS_M33L (open red bar). Cells were shaken in the TK2420 minimal medium adding 25 mM (D), or 50 mM (E) KCl at 37°C under aerobic conditions. The results are the averages of three independent duplicate experiments, with error bars representing the standard deviations.