FIG. 4.

Growth of A. actinomycetemcomitans JP2arcB1 under iron limitation. Cultures of A. actinomycetemcomitans JP2arcB1 (ArcB deficient) and JP2arcB1YGS (ArcB complementation of strain JP2arcB1) were inoculated at the identical cell density and incubated at 37°C for 7 h (late exponential phase) in BHI medium (black columns) or in BHI medium supplemented with 250 μM EDDHA (gray columns). Cell density (CFU/milliliter) for each culture was determined as described in Materials and Methods.