Figure 3. Relationships between bacterial family abundances and gut environments.

(a) Spearman's rank correlation coefficients between bacterial family abundances and gut environmental factors such as pH, organic acid concentrations and faecal oligosaccharide concentrations are shown in numerical and colour-scale formats. (b) Spearman's rank correlations of oligosaccharide concentrations with pH values and acetate concentrations. (c) Relationships between bacterial abundances, faecal oligosaccharide concentrations and the relative abundances of bifidobacterial species. The upper tree shows hierarchical clustering on the basis of the bacterial family compositions. (d) Growth curves of 29 bifidobacterial strains in medium containing HMOs (see Supplementary Fig. 14 for more details). (e) Glycoprofiles of bacterial supernatants after 40 h of cultivation. Samples are ordered based on their OD₆₀₀ values after 40 h of cultivation.