Extended Data Fig. 6: Quantitation of peptide levels in feces of treated mice.
From: Directed remodeling of the mouse gut microbiome inhibits the development of atherosclerosis
a, Representative LCMS selected ion traces used to generate standard curves for determining the concentration of peptides in extracted mouse feces. The traces correspond to ion 1181.8 ([M-H]1−) for c[wLwReQeR] and ion 368.2 ([M + 3 H]3+) for c[wLwKhShK] at the peptide concentrations shown. Standard curves were generated from two independent extractions. b, Standard curves used for quantitation of c[wLwReQeR] and c[wLwKhShK] concentrations in the feces of treated mice. Data are shown as mean ± SD of n = 2 independent replicates for each concentration. c, Measured quantities of feces (dry weight after lyophilization of fecal pellets) excreted by individually-housed WD-fed LDLr−/− mice over 24-h periods (n = 32). Data are shown as mean ± SD. The observed mean ± SD value was 432 ± 61 mg feces/day/mouse. d, Measured levels of fully intact peptides in the 5-wk fecal samples of treated LDLr−/− mice (n = 4 animals per group). Each circle represents the average of duplicate measurements from a single animal. Data are given as mean ± SD of the values for the 4 animals in each group. The observed fecal concentrations of the fully-intact peptides of 1.0 ± 0.1 nmol peptide/mg feces and 0.9 ± 0.2 nmol peptide/mg feces for c[wLwReQeR] and c[wLwKhShK], respectively, represent greater than 50% of the level that would be expected assuming all of the administered peptide was excreted in the feces (~1.7 nmol peptide/mg feces). The estimated maximum fecal peptide concentration that would be expected assuming all of the administered peptide was excreted in the feces was calculated from the known concentration of peptide administered in the drinking water (0.18 mM), the average daily volume of treated drinking water consumed by each mouse (4.5 mL), and the average daily amount of feces excreted by each mouse (432 mg).
