Transcriptional analysis of PflaA, Pami, PflgB and PflaB promoters using gfp as a reporter. The levels of GFP in (a) Escherichia coli and (b) Borrelia burgdorferi were detected by Western blot analysis. Approximately 10 μg of whole cell lysates were run by SDS-PAGE. The flagella motor switch complex protein, FliG, and the flagella filament protein, FlaB, were used as internal controls in E. coli and B. burgdorferi, respectively. The monoclonal antibodies against GFP and FlaB, and polyclonal antiserum against E. coli FliG, were used. (c) Quantitative Western blot analysis of GFP levels in E. coli and B. burgdorferi. Protein density was determined by FluorChem spot densitometry (Bio-Rad). Data were expressed as mean of density unit±SD of the mean from three independent experiments.