Figure 5.

O-PLS-DA coefficient plots derived from the UPLC–MS bile acid composition. O-PLS-DA coefficient plots derived from the bile acid composition obtained by UPLC–MS analysis of ileal flushes, indicating discrimination between conventional (positive) and HBF colonized mice (negative) (A), and partial discrimination between conventional (positive) and re-conventionalized mice (negative) (B). The color code corresponds to the correlation coefficients of the variables. One predictive and one orthogonal components were calculated, and the respective (Q²Y, R²X) are (89.1%, 80%) and (51.4%, 62%). The O-PLS-DA coefficient plots are presented using a back-scaling transformation, as described previously (Cloarec et al, 2005b), which allows each variable to be plotted with a color code that relates to the significance of class discrimination as calculated from the correlation matrix.