Fig. 4.
Effects of scandium on the expression of PamyE-lacZ and PywfB-lacZ. Strains TI416 [amyE::(PamyE-lacZ cat)] (A) and TI351 [amyE::(PywfB-lacZ cat)] (B) were grown in NG medium without (white thick bars) or with (gray thick bars) scandium chloride at a concentration of 10 μg/ml. Culture samples were withdrawn at the indicated time points, and β-galactosidase activity was determined as described previously (8). The average values (with standard deviations) for three independent experiments are shown. The asterisks denote significant differences (P < 0.05).