Fig. 2. Pairwise cultivation of infant gut-associated bifidobacteria.

a Experimental design. Pairwise culturing experiments were performed for all possible combinations. In simultaneous cultures, both species were introduced together into medium supplemented with HMOs at the beginning of the experiment (at 0 h). To test for the effect of assembly history, the first species was inoculated at the beginning of the experiment, and the second species was inoculated 12 h later. b–g Culturing results for each pair. Total OD₆₀₀ indicated by the black line, was measured at each time point, and the relative abundance of each species was quantified using qPCR. The relative abundance of each strain is indicated by different colors (blue: B. bifidum, green: B. breve, orange: B. infantis, red: B. longum). Relative abundances at 0 h are calculated theoretical values. Data showing the total OD₆₀₀ represent averages and error bars represent ±standard deviation of biological quadruplicates. The bar graphs showing the relative abundances of each species show averages of biological quadruplicates. b B. bifidum and B. infantis pair. c B. bifidum and B. longum pair. d B. bifidum and B. breve pair. e B. infantis and B. breve pair. f B. infantis and B. longum pair. g B. breve and B. longum pair.