In Vivo Solution-state NMR-based Environmental Metabolomics

This article presents a short review of environmental in vivo NMR along with a systematic protocol for in vivo solution-state NMR-based metabolomics for the cladoceran Daphniamagna, using room temperature NMR probes. In vivo metabolomic studies are essential for monitoring and understanding the biochemical pathways behind the physiological changes that occur in aquatic organisms on exposure to environmental contaminants. To this end, conventional solution-state NMR spectroscopy provides the most comprehensive overview of the metabolic profile, without exerting any additional stress on the organisms. Parameters such as the survival of organisms, signal-to-noise ratio, and gut clearance of D. magna are optimized in accordance with NMR data, and the resulting protocol is applied to C-13-enriched D. magna. Assignment of a range of metabolites is made possible by H-1 and C-13 one-and two-dimensional NMR spectroscopy, and a limited baseline metabolite profile for C-13-enriched D. magna is established. Differences in the lipid and carbohydrate profile of daphnia of differing physiologies (male vs. female, pregnant vs nonpregnant) are also identified, demonstrating the viability of this approach for elucidating metabolomic changes. Finally, the limitations of solution-state in vivo NMR spectroscopy using a room temperature probe are identified, and potential solutions are proposed.