FIGURE 7.

The free iron content determines the physiological impacts of the Fur loss. (A) Suppressing effects of iron chelators on the fur deletion based on cyt c biosynthesis. Dip, 2,2-dipyridyl. pBsdpaAB, B. subtilis dpaAB gene under the control of Ptac within pHGE-Ptac. (B) Relative concentrations (RC) of total and free iron in WT and Δfur strains. Cultures of indicated strains entering the stationary phase were collected and their total iron and free iron contents were determined. The averaged levels of WT were set to 100%. Con, no chelator; DFO-2 and -5, DFO at 2 and 5 μM; Dip-50 and -100, dipyridyl at 50 and 100 μM; IPTG-0.2 and -1, pBsdpaAB with IPTG 0.2 and 1 mM. Asterisks indicate statistically significant differences of the value compared to that of the WT and between values linked by bracket (*P < 0.05; **P < 0.01; ***P < 0.001). Experiments were performed at least three times, and data were presented as means ± SEM or by representative results.