Figure 7. HssRS and HitRS cross-regulate.

(A) Cross-regulation of phrt by HitRS. B.anthracis Sterne and ΔhitRΔhssS were transformed with the xylE reporter plasmid, phrt. The strains were treated with either 20 μM NDGA or vehicle (ethanol). Cultures were grown for 24 h and harvested. Cells were lysed and XylE activity was quantified. Error bars represent ±SEM of data averaged from three independent experiments performed with biological triplicates. The significance was calculated by an unpaired Student's t-test, where ***  =  P≤0.0001. (B) WT was grown to mid-log and pulsed with the indicated compound for 10 min. cDNA was generated from RNA isolated from the cultures. Shown is the abundance of hrtA and hitP transcripts under each of the experimental conditions relative to vehicle (DMSO), as quantified by qRT-PCR. Each sample was internally normalized to 16S RNA abundance. All compounds were prepared in DMSO and diluted 1000x into the growth media for a final concentration of 10 μM heme, 50 μM ‘205, 100 μM chlorpromazine, 20 μM NDGA, and 42 μM targocil. Error bars represent ±SEM of data averaged from three independent replicates. The significance was calculated by a two-tailed Student's t-test, comparing the ΔCt of each experimental condition to the ΔCt of vehicle (DMSO). Each P-value ≤0.1 is listed above the experimental group.