Figure 4.

HlyU mediated phlyA activation followed by quantitative RT-PCR.A, model of the mechanism of HlyU regulation of the hlyA gene, HlyU DNA dissociation leads to H-NS (green)–mediated repression. B, quantitative RT-PCR performed over a ΔCTX Δfur ΔhapR Vibrio cholerae strain with the addition of Na₂S or H₂O₂. The bar chart shows the fold changes of induction of Vc hlyA after addition of Na₂S (red) and H₂O₂ (blue), with transcript values normalized relative to the transcription level of recA. The values correspond to transcript levels relative to unstressed (UN) (middle sand bar) and are shown as mean ± SD from three replicate cultures. Statistical significance was established using a paired t test relative to UN under the same conditions (∗∗p < 0.01, ∗p < 0.05). Lines on the top of the chart show statistical significance relative to ΔCTX Δfur ΔhapR V. cholerae mutant strain UN.