FIGURE 2.

Effect of growth medium and dilution ratios on CSP-induced sigX expression profiles. (A–C) The sigX reporter type strain (MI055; p_sigX luc) was grown in 200 μL of TSB, C+Y, or C+Y_{Y B} in a 96-well plate in air at 37°C with 150 nM CSP. ^∗ Significant statistical difference in C+Y_{Y B} when compared to C+Y and TSB (p < 0.05). (D–F) Comparison of sigX expression profiles and culture growth in pre-culture dilution ratios of 1:10, 1:50, or 1:100. Strain MI055 (p_sigX luc) was grown in 200 μL volumes of C+Y_{Y B} in a 96-well plate in air at 37°C with 150 nM CSP. ^∗ Significant differences on sigX expression comparing 1:10 and 1:50 to 1:100 (p < 0.05). For media comparison, pre-cultures were prepared in TSB and on the day of experiment they were centrifuged and re-suspended 1:100 in fresh medium – TSB, C+Y or C+Y_{Y B}. For all figures, sigX expression, presented as relative luminescence units (RLU), and culture optical density (OD) were measured periodically. The results are averages from 3 replicates and representative of three independent experiments. Error bars represent standard error of the mean. Differences in sigX expression among media and dilutions rates were analyzed by two-way ANOVA.