Fig. 4: Identification of GM contributing to ceramides production by hosts.

a PCA plots showing microbial compositional difference derived from metagenomic data at genus level between the two groups. b Relative abundance of substantially changed bacteria taxa at the order level. c Relative abundance of substantially changed bacteria taxa at the genus level. d Taxonomic cladogram obtained using LEfSe analysis. Taxonomic levels are represented by the rings from phylum level (innermost ring) to species level (outermost ring). LEfSe identified the taxa (highlighted by small circles and by shading) with significant differences in abundance value between the two groups. The colors of the circle and shading indicate the microbial lineages that are enriched within the corresponding groups. The diameter of each circle is proportional to taxon abundance. e Bar graph showing the relative bacterial abundance at the species level. f Evaluation of levels of ceramides in supernatant of the culture medium of L. reuteri. g Evaluation of levels of ceramides in supernatant of the culture medium of B. pseudolongum. h Quantitative analysis of gut ceramides in Abx mice gavaged with B. pseudolongum. Measured concentrations (ng) were normalized to fecal weight (g). i Quantitative analysis of gut ceramides in Abx mice gavaged with L. reuteri. Measured concentrations (ng) were normalized to fecal weight (g). N = 6 for each group. Comparisons were performed using Welch’s t test (b, c, e) and unpaired t tests (f, g, h, i). *p < 0.05, **p < 0.01, ***p < 0.001.