Fig. 5.

β-galactosidase activity was measured in wild-type (PK6364) or mutant (PK8120, PK8122, PK7783, PK6828, PK7759, PK6564, PK6826, PK6848, PK7540, PK7751) strains containing P_iscR fused to lacZ integrated at the λatt site. Cultures were grown under A) aerobic or B) anaerobic conditions in MOPS minimal media supplemented with glucose (0.2%); for the wild-type, ΔiscSUA, ΔiscSUA-hscBA-fdx, ΔiscS, ΔiscU, ΔiscA strains, media were also supplemented with nicotinic acid (12.5 µg ml⁻¹), and thiamine (2 µg ml⁻¹). Fold repression was determined by dividing the β-galactosidase activity present in the strain lacking IscR (PK6512), grown in the presence or absence of nicotinic acid and thiamine, by the β-galactosidase activity measured for each strain and error bars represent the propagation of standard errors for three biological replicates. ND, not determined.