Biofilms formed by P. aeruginosa PA14, ΔnicD, and ΔnicD mutant strains overexpressing nicD, nicD-GGAAF and nicDΔNoTMR under the control of the arabinose-inducible promoter of the pMJT1 vector were grown for 5 days in flow cells under flowing conditions. Multicopy expression of nicD but not nicD-GGAAF or nicDΔNoTMR restores biofilm dispersion upon glutamate exposure to wild type levels. Confocal images were acquired at the same position, prior to and following induction of dispersion by L-glutamate. Representative images are shown. White size bar, 100 µm. Blue vertical size bar (indicating height), 40 µm.