FIGURE 6.

Biofilm stimulation at different iron concentrations in the C. jejuni strains whose biofilm formation was enhanced by neither 40 μM Fe²⁺ nor 20 μM Fe³⁺ (A), by 40 μM Fe²⁺ but not by 20 μM Fe³⁺ (B), and by 20 μM Fe³⁺ but not by 40 μM Fe²⁺ (C). The results show the means and standard deviations of three samples in a single experiment. Similar results were observed in all experiments repeated three times independently. The statistical analysis was performed with Student’s t-test in comparison with the control without iron treatment. ^∗P < 0.05.