Table 1.

Effects of pH and salt on the initial rate of K+ uptake in strain TK2469

Type of K+ uptake measurement and [K+] (mM)ConditionK+ uptake (μmol g−1 min−1)
K+-depleted cellsa
 40pH 7.4318.2
 40pH 7.139.4
 40pH 6.74.8
Osmotic upshockb
 400.3 M NaCl added2.6
 400.15 M NaCl + 0.25 M glucose added3.5
 400.5 M glucose added6.7
  • a Cells were grown in standard K115 medium, depleted of K+ by treatment with 2,4-dinitrophenol, suspended at 5 × 109/ml in 0.1 M NaCl, and added to growth medium with the indicated pH and K+ concentration.

  • b Cells were grown in standard glucose K115 medium and diluted into medium containing the indicated additional osmotic solute(s) and a final K+ concentration of 40 mM.