Figure 1

GFP expressions under different promoters in iron-limitation (A), under P _fhuA in variant iron concentrations (B). A. E. coli Top10 transformants harboring p_tP_XG were cultured in LB medium to OD₆₀₀ = 0.8 and induced by 200 μM 2,2’-dipyridyl. Samples were taken at 20 h after induction for GFP assay; B. LB medium with 40 μM FeSO₄ as iron-rich condition, LB medium with 200 μM 2,2’-dipyridyl as iron-limiting condition. The error bars represent the standard deviation (SD) for one independent experiment, performed in triplicate, the experiment was repeated for three times.