FIG. 6.

Iron regulation and alcR-dependent expression of a fauA-lacZ transcriptional fusion gene. Transcriptional activity of a fauA-lacZ fusion gene carried as plasmid pBB24/mini-Tn5 lacZ1 in wild-type B. bronchiseptica B013N (alcR+) or isogenic alcR mutant strain BRM11 (alcR mutant) was assessed by measuring β-galactosidase activity of bacteria cultured under iron-replete (■) and iron-depleted (□) conditions. Mean β-galactosidase activities ± standard deviations (n = 3) are shown in Miller units.