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. Author manuscript; available in PMC: 2015 Jan 7.
Published in final edited form as: Cell Metab. 2014 Jan 7;19(1):73–83. doi: 10.1016/j.cmet.2013.11.024

Figure 3. Detection and identification of endogenous DAF-12-ligand candidates via 2D NMR-based comparative metabolomics and SIM-GC/MS.

Figure 3

(A) dqfCOSY spectrum of inactive daf-9;daf-12 metabolome fraction corresponding to active region I (Figures 2C–2E). Enlarged section (upper left) compares daf-9;daf-12 with the corresponding section of the daf-22 spectrum, showing one of the differential crosspeaks (red) that led to identification of Δ1,7-DA, next to non-differential signals representing a metabolite present in both daf-9;daf-12 and daf-22, an epidioxy sterol (blue). Enlarged section (lower right) shows example crosspeaks from the comparison of the spectra of strm-1 (vide infra) and daf-9;daf-12 metabolomes, showing signals (green) characteristic for Δ7-DA in the strm-1 spectrum but not the daf-9;daf-12 spectrum.

(B) SIM-GC/MS of active daf-22 metabolome fraction indicating the presence of Δ1,7-DA. The additional peak at ~29.4 min in the ion trace m/z = 426 belongs to an unrelated compound.

(C) SIM-GC/MS of synthetic Δ1,7-DA confirm retention times and fragmentation patterns.

(D) Major EI-MS fragments of Δ1,7-DA used in Figures 3B and 3C.

See also Figure S2