Fig. 2.

ATP inhibits the growth of stool aerobic bacteria in vitro. Mouse stool samples were collected fresh directly in Brain Heart Infusion (BHI) media, homogenized, serially diluted and then cultured under aerobic conditions. For aerobic growth, each bacterial culture (200 μl) was grown in 8 wells of a 96-well clear-bottom plate at 37°C in a shaking incubator, and absorbance (OD₆₀₀) was determined at indicated time points (see materials and methods). A: effects of different targets of IAP on stool aerobes. B: the effect of ATP on bacterial growth was most evident when optical densities (ODs) were compared after 10 h of incubation [1-way ANOVA F_{(4, 38)} = 4.49, P value < 0.01; Tukey's post hoc test: P value < 0.05]. C: dose-response effects of ATP on stool aerobes. D: the highest effect of low concentration of ATP on bacterial growth was evident after 8 h of incubation [1-way ANOVA: F_{(9, 68)} = 49.30, P value < 0.001; Tukey's post hoc test: P value = 0.015 for 200 μM of ATP, P values < 0.001 for 400, 800, 1,600 μM of ATP]. E: effects of ATP derivatives on stool aerobes. F: these effects are also illustrated at the final time point. G: IAP reverses the inhibitory effects of ATP on stool aerobic bacterial growth. H: IAP abolished the effects of ATP and dose dependently increased bacterial growth [1-way ANOVA: F_{(5, 83)} = 13.97, P value < 0.001; Tukey's post hoc test: P values < 0.001]. Values for bacterial growth are expressed as average absorbance (OD₆₀₀) ± SD. The experiment was repeated at least 3 times showing similar results.