Figure 2. Scheme showing the number of genes differentially expressed in the five contrasts.

S. coelicolor M145 and S. coelicolor ΔargR were grown in absence (A and C) or in presence of 25 mM arginine (B and D). The arrow orientation refers to the comparison between two conditions. Differential transcription values were obtained by subtracting the Mg values of the first condition from those of the second condition (corresponding to the arrowheads). The small vertical arrows indicate the number of genes up-expressed (up-oriented arrows) or down-expressed (down-oriented arrows) in each of the contrasts. Contrast 5 is the interaction contrast that reflects the differential response to the arginine supplementation of the two strains.