FIG. 3.

Riboflavin uptake by C. jejuni NCTC11168 is iron and riboflavin responsive and is increased in the fur mutant. Shown are rates of tritiated [G-³H]riboflavin uptake in the C. jejuni wild-type strain, ribB mutant, and fur mutant. Cultures were grown in riboflavin-free MEMα under iron-limited (1 μM FeCl₃; indicated as −iron) and iron-replete (40 μM FeCl₃, indicated as +iron) conditions with and without supplementation with 50 μM riboflavin (indicated as −riboflavin and +riboflavin). Data shown are from two independent experiments performed in triplicate. The ribB mutant could not be tested in medium without riboflavin because of the riboflavin auxotrophy; the absence of data for these samples is indicated by asterisks.