Fig. 3

Quantification of penicillin production of strains with different copy numbers of the pcbC gene. The strains were grown for 96 h in shaking cultures. The diameter of each halo was measured to calculate the area and is given in relation to the dry weight of the respective culture. Standard deviations were determined from representative isolates, which were measured in triplicate. The copy number of each strain is displayed above the corresponding column. For all strains with a copy number of 1 or 2, the number indicates both the copy number of the pcbC gene and the complete cluster. For ΔpcbC T7-1, one copy of both pcbAB and penDE is still present, whereas pcbC is missing. To generate ΔpcbC::pcbC-gfp, the ΔpcbC recipient was complemented with three ectopic integrations of a pcbC-egfp fusion construct. For comparison, wild type strain NRRL 1951, which carries one copy of the penicillin cluster, is given