FIG 8.

Effect of doubling the concentration of tryptone or yeast extract on motility. Average areas of motility were measured for each concentration. The double-concentration areas were then divided by the single-concentration areas to get the ratios shown. Doubling the tryptone had a positive impact on flagellum-mediated motility, significantly increasing both wt and ΔdipA strain swimming and swarming. However, doubling the yeast extract only increased swimming motility and had no impact on swarming in either strain. All assays were performed in triplicates. *, P value of <0.05 compared to the 1× concentration; **, P value of <0.01 compared to the 1× concentration.