FIG. 4.

Lactose counterflow in L. plantarum ATCC 14917. The cells were grown on CDM containing 0.5% (wt/vol) glucose (glu) plus 0.5% (wt/vol) lactose (lac) or 0.5% (wt/vol) glucose plus 30% (wt/vol) lactose. The cells were washed and resuspended in potassium phosphate (pH 6.5). After equilibration with 2.5 mM lactose on ice for 3 h, the cells were diluted 50-fold (final protein concentration, 0.3 to 0.4 mg/ml) into potassium phosphate containing 72 μM [¹⁴C]lactose (55.8 mCi/mmol) without (open symbols) or with (inset; closed symbols) 10 mM glucose.