Fig 3.

Requirement of menaquinones for ArcB activation in vivo. Cultures of strain ECL5003 (wt) (A), its isogenic strain IFC5006 (ΔmenFDHB) (B), IFC5006 complemented with plasmid pMX538 (pmen⁺) (C), and IFC5006 in the presence of 1,4-dihydroxy-2-naphtoic acid (DHNA) (D), all bearing the ArcB activatable cydA′-lacZ reporter, were grown aerobically in LB broth containing 0.1 M MOPS (pH 7.4) and 20 mM d-xylose. At an OD₆₀₀ of 0.2, one aliquot was withdrawn for measuring the β-galactosidase activity (depicted as 0 min) and the rest of the culture was divided in two. One part was kept under aerobic conditions (empty diamonds) as a control, whereas the other was shifted to anaerobiosis (filled diamonds), and the time course of the β-galactosidase activity was followed. Data represent the averages from four experiments, and the standard deviation values are indicated.