The ratio of D-aa to L-aa in feces is decreased in patients with active UC. (A) Experimental design. (B) The ratio of D-aa to L-aa in serum or fecal samples from HCs (n = 15) and UCs (serum, n = 6; feces, n = 9). NS, Not significant; ∗P < .05; ∗∗P < .01; ∗∗∗P < .001 between groups; Student t-test. (C) PCoA plots of unweighted UniFrac distance of fecal microbiota from HCs and UCs. (D) Alpha and beta diversity measures. Plots are observed OTUs and Shannon indexes. ∗P < .05; ∗∗P < .01, between groups, Student t-test. (E) LDA scores higher than 2. Healthy donor group with a positive score (blue) and UC patient group with a negative score (red). (F) Correlation between the ratio of fecal D-aa to L-aa and the microbiome. Featured microbiomes from (E) are in blue (HC) and red (pUC). The strength of the correlation between each pair of variables is indicated by the diameter and color of the circles. A color code of dark blue indicates a positive correlation coefficient close to +1, and a color code of dark red indicates a negative correlation coefficient close to −1. Data are shown as standard error of the mean.