Fig 4.

Role of Fur in the response of luminescence to low iron. (A) Cultures of wild-type ES114 (circles) or the Δfur mutant YLM111 (triangles) were grown in aerobic shake flasks in SWTO medium supplemented with 43 μM FeSO₄ and either 20 mM citrate or no citrate. Error bars indicate standard deviations (n = 2). (B) Cultures of Δfur mutant strain YLM111 were grown in SWTO medium supplemented with 43 μM FeSO₄ without further additions or supplemented with 20 mM citrate or with 20 mM citrate and 2 mM additional FeSO₄. Error bars (some too small to visualize) indicate standard deviations (n = 3). The data in each panel are from one experiment representative of at least three independent experiments.