Low pH promotes biofilm strengthening by Esp452.

A. Luminescence of MMH594b (Δesp) biofilms grown in either 0.18% or 0.50% glucose, and with PBS, Esp453-743, or Esp452. The experiment was conducted with triplicates. Samples from three independent experiments were compared by 2-way ANOVA and Tukey’s test. **** p B. The pH of biofilm cultures of MMH594b grown in TSB with 0.18 or 0.50% glucose, and with Esp452, Esp453-743, or PBS. The experiment was conducted with triplicates. Samples from three independent experiments were combined and compared by 2-way ANOVA and Tukey’s test. **** p C. OD400 of Esp fragments (25 μg) incubated in sodium citrate buffer at the indicated pH for 24 h. Experiments were conducted with duplicates. Samples from three independent experiments were combined and the SEM is indicated with error bars. D. Fluorescence of Thioflavin T incubated for 24 h with Esp fragments (25 μg) in sodium citrate buffer at the indicated pH. Experiments were conducted with duplicates. Samples from three independent experiments were combined and the SEM is indicated with error bars.