FIG. 6.

Effect of fructose on lactose metabolism by growing cells. Cells were grown overnight in the presence of 0.2% lactose. An 0.5-ml aliquot was used to inoculate 15 ml of fresh medium containing 0.2% (wt/vol) lactose. When the culture reached mid-log phase, the medium was supplemented with 0.1% (wt/vol) fructose (indicated by the arrows). The symbols represent the OD₆₆₀ (●) and the consumption of lactose (○) and that of fructose (□).