FIG. 1.

Dependence of the initial rate of glycine betaine uptake on increases in medium osmolality imposed by KCl. Cells of L. plantarum ATCC 14917 were grown on CDM containing 0.8 M KCl, washed, and resuspended in 50 mM potassium phosphate (pH 6.5). The concentrated cell suspensions were diluted in 50 mM potassium phosphate (pH 6.5) to a final protein concentration of 0.13 mg/ml. After 8 min of preenergization with 10 mM glucose, uptake was initiated at time zero by the addition [¹⁴C]glycine betaine (final concentration of 1.3 mM) plus KCl as indicated. The initial uptake rates were determined and plotted against the concentration of KCl that was added to the 50 mM potassium phosphate.