Fig 1.

Characterization of the ΔDTXR strain. (a) Growth of ΔDTXR and the parent (COM1c2) strains under iron-sufficient (+Fe, 10 μM iron added) and iron-limited (−Fe, no iron added) conditions. Growth was monitored by optical density at 660 nm. Results are shown for COM1c2 (circles) and ΔDTXR (triangles) under iron-sufficient (solid symbols) and iron-limited (open symbols) conditions. The arrow indicates the culture harvest point for RNA isolation for DNA microarray analysis. (b) The effect of dtxR deletion on gene expression was measured in ΔDTXR and COM1c2 using quantitative PCR. Total RNA was prepared from ΔDTXR and COM1c2 grown under iron-sufficient and iron-limited conditions. The constitutively expressed gene encoding the pyruvate ferredoxin oxidoreductase (POR) gamma subunit (PF0971) was used as an internal control. Results are expressed as a change in gene expression, comparing ΔDTXR to COM1c2 under iron-sufficient (closed bars) and iron-limited (open bars) conditions.