Motility assays were performed using DMEM soft agar plates. Motility ring diameters of the wild type 14028s strain and a negative control (fliA) were compared to preA, preB, and preAB strains. Signaling molecules were tested for possible affects on motility. (A) 20 μM AI-2 (dark bars) or an equal volume of buffer (light bars) were added to the medium. (B) 50 μM epinephrine (dissolved in acidified water, dark bars) or an equal volume of acidified water (light bars) was added to medium. An asterisk (*) denotes statistical significance with a p-value < 0.02 as determined with a student t-test. The asterisk in (A) is in comparision of ΔpreB to the wild type strain.