Annotated 13C-labeled metabolites detected in DGM-D-13C15N-incubated EBs by a combination of ICR/FT-MS and UPLC-MS.

a)The detected m/z is given for each ion species with the instrument given accuracy.b)Labeled metabolites were considered to be present in extracts of DGM-D-13C15N-incubated EBs when peaks corresponding to the exact mass of the unlabeled metabolites were detected in the DGM-D-incubated controls and observed mass shifts were consistent with the exchange of 12C by 13C atoms. Metabolites containing single 13C atoms were also observed in extracts from DGM-D-incubated EBs, due to the natural isotopic distribution of carbon, and were thus excluded.c)The detection method (A: ICR/FT-MS; B: UPLC-MS) is indicated, as well as the ion species detected (H: [M-H+]−; Cl: [M+Cl−]−).d)These metabolites were detected by ICR/FT-MS analysis in purchased D-[U-13C6]-glucose and were thus not considered as host-free synthesized metabolites.