FIG 4.
Quercetin blocks agglutination but shows no impact on M. xanthus EPS level. (A) Effect of quercetin on M. xanthus agglutination. OD600 of M. xanthus cells in agglutination buffer at an initial OD600 of 0.9 were monitored over time in the presence of quercetin at the indicated concentrations. Shown are the averages and standard deviations (error bars) from three independent experiments, each of which was conducted in triplicates. Agglutination with 8 μM and 16 μM quercetin was indistinguishable from the control without quercetin, and their results are shown as insets to avoid curve overlap. (B) Effect of quercetin on M. xanthus EPS levels. EPS levels of M. xanthus in the presence of quercetin at specified concentrations were examined on plates with the fluorescent dye calcofluor white as described in M&M. The intensity of the fluorescence reflects EPS levels in this assay.