FIG 1.
Promoter activity in M. capsulatus. (A) GFP fluorescence in M. capsulatus expressing GFP from the tetracycline promoter/operator (PtetA) in pCAH01::GFP. Where indicated, GFP was induced by plating on NMS agar supplemented with 500 ng/ml aTc for 72 h. The empty pCAH01 plasmid was used as a negative control. (B) GFP fluorescence in M. capsulatus with GFP expression controlled by the indicated gene promoters in pQCH::GFP. Fluorescence intensity was measured from cells grown on NMS agar with or without 5 µM CuSO4 for 72 h. (C) GFP fluorescence in E. coli expressing GFP from the indicated promoters in pQCH::GFP. Fluorescence intensity was measured from cells grown to an OD600 of 0.5 in LB liquid medium. In panels B and C, the promoterless pQCH::GFP plasmid was used as a negative control. The data represent the fluorescence intensity normalized to OD600 and are depicted as mean RFU and standard deviations (SD) from 3 independent replicates. ***, P < 0.001; *, P < 0.05; ns, not significant.