FIG. 4.

Expression of the full-length IraD promoter fusion (iraD::luxCDABE) in strains lacking DksA. Each data point is an average of four independent determinations. The variability is shown with error bars in both graphs. RLU, relative luminescence units (bioluminescence counts per minute, normalized to the OD₆₀₀). (A) Wild-type and dksA strains on graph represent data from iraD::luxCDABE expression in the MG1655 and ΔdksA::FRT cat strains, respectively. (B) Northern blot analysis of iraD transcripts in the MG1655 and ΔdksA::FRT cat strains. Samples were prepared from cell grown to either an OD of 0.7 (±0.1) or 1.6 (±0.1) as indicated. The graphs below the Northern blots show quantification of each transcript in that condition relative to 16S rRNA loading control, in the strain indicated. Gray bars represent the smaller transcript of 500 nt, and the black bars represent the larger transcript of 800 nt.