FIG 3.

Riboflavin production alters upon iron addition or sequestration and PKA activation. SC5314 cultures were grown for 24 h in the presence of FeCl₃ (a), an iron chelator, ferrozine (b), or dbcAMP (c). (d) CaTPK1 and CaTPK2 overexpression strains were grown for 24 h, as well as the empty vector (EV) control strain. The fluorescence was measured at 530 nm when excited upon 450 nm. The average and the SEM of relative fluorescence to OD₆₀₀ ratios are shown. Statistical analysis was performed using a one-way analysis of variance (ANOVA) statistical test with Bonferroni correction (comparison to culture without added compound). *, P < 0.05; **, P < 0.01; ***, P < 0.001; ****, P < 0.0001.