Figure 1

Acetate growth effect and butyrate production in F. duncaniae A2-165 cultures. (A) Schematic view of the importance of acetate in the butyrate biosynthetic pathway. The production of butyrate is dependent on glycolysis and the butyrate cycle. The key enzyme for butyrate production is butyryl-CoA:acetate CoA-transferase (ButCoAT), which consumes extracellular acetate to produce butyrate and acetyl-CoA from butyryl-CoA. (B) Growth kinetics of F. duncaniae A2-165 under high- and low-acetate conditions. Growth kinetics are shown for bacteria cultured in BHIS medium with 23 mM acetate (high-acetate, orange color) or with 3 mM acetate (low-acetate, blue color). Arrows indicate time points of sampling for the RNA-Seq transcriptome analysis. Sampling was performed after 7 h (late exponential phase, E and Ea for low- and high-acetate conditions, respectively) and 10 h (early stationary phase, S and Sa for low- and high-acetate conditions, respectively) of growth. N = 4, median with interquartile range (IQR) is shown. (C) Individual growth-rate measures in high/low-acetate conditions. N = 4, raw data, median with IQR are shown. (D) SCFA concentrations (expressed as molarity) of E/Ea and S/Sa culture supernatants. Butyrate production is presented as positive values while acetate consumption is presented as negative values. Acetate values were normalized with the acetate value of BHIS medium, which contains 3 mM of acetate. N = 4, median with IQR is shown. (E) Overview of RNA-Seq data. The number of (differentially expressed) DE genes for each comparison is presented in the form of a bar chart. Two-group comparisons were conducted between high- and low-acetate conditions in the late exponential phase (Ea vs. E) and early stationary phase (Sa vs. S). Additionally, two-group comparisons were performed between the early stationary and late exponential phases in high-acetate (Sa vs. Ea) and low-acetate (S vs. E) conditions. log₂FC ≥ |2|, FDR-adjusted p-value ≤ 0.01.