Fig. 1.

Western-type HFD markedly decreases fecal bacterial glycine lipids and fecal microbiota diversity. Structures of bacterial glycine lipids used for experiments (L567, L654, and L1256) depicting the dominant lipid species within each lipid class (A). Cecal feces were aseptically collected for characterization of 16S V4 region (B, C). Measures of fecal microbiota alpha diversity (B) and fecal Bacteroidetes (C) of Ldlr^−/− mice housed in different cages and fed either a standard low-fat chow diet or Western-type HFD for 14 weeks (n = 6–11, mean ± SEM). Lipids were extracted from feces and L654 (D), and total bacterial glycine lipids (E) were quantified by UPLC-MS/MS (C, D) (n = 5–20, mean ± SEM). Serum L654 was quantified by UPLC-MS/MS after pooling three individual animals per sample (n = 2–3 pooled, mean ± SEM). Statistical significance determined by two-tailed Student’s t-test (∗P < 0.05, ∗∗P < 0.01, and ∗∗∗∗P < 0.0001).