FIG 7.
Xylose represses the expression of arabinose transporters and the transcriptional activator AraC. The response was measured in a single strain containing a single-copy, chromosomal transcriptional fusion of the ParaC (A), ParaE (B), or ParaF (C) promoter to the Venus fluorescent protein. Fluorescence values were averaged from single-cell, flow cytometry data. Error bars denote the standard deviations from three experiments performed on separate days. Histograms for these data are provided in Fig. S4 in the supplemental material. Note that higher arabinose concentrations were required in order to induce expression from the ParaE promoter.