A precursor application system was developed to allow the study of Erythrina alkaloid formation in Erythrina crista-galli. Fruit wall tissue of this species was recognized as the major site of alkaloid biosynthesis. The application of radioactively and 13C-labelled potential precursors showed that the hitherto assumed precursor (S)-norprotosinomenine was not incorporated into the Erythrina alka...

Introduction Acetate is a known glia-specific substrate and has been used to study cerebral metabolism and neurotransmission in both human subjects and animals [1-3]. In particular, intravenously administered 13C-labeldd acetate can be used to label cerebral glutamine and glutamate, allowing glutamate-glutamine interactions to be monitored in vivo using 13C MRS and/or proton-detected 13C MRS [4...

In the present study, we applied nuclear magnetic resonance (NMR), as well as near-infrared (NIR) spectroscopy, to Jatropha curcas to fulfill two objectives: (1) to qualitatively examine the seeds stored at different conditions, and (2) to monitor the metabolism of J. curcas during its initial growth stage under stable-isotope-labeling condition (until 15 days after seeding). NIR spectra could ...

The response in whole-body and splanchnic tissue mass and isotope amino acid transfers in both plasma and blood has been studied in sheep offered 800 g lucerne (Medicago sativa) pellets/d. Amino acid mass transfers were quantified over a 4 h period, by arterio-venous procedures, across the portal-drained viscera (PDV) and liver on day 5 of an intravenous infusion of either vehicle or the methyl...

We evaluated the applicability of stable isotopic tracers to the study of intramuscular fatty acid metabolism by infusing both [U-13C]palmitate and [1-13C]oleate intravenously for 4 h into fasted conscious rats. Skeletal muscles were sequentially biopsied, and the concentration and 13C enrichment of fatty acids were measured by gas chromatography/combustion/isotope ratio mass spectrometry. Thro...

13C NMR of isotopically enriched metabolites has been used to study the metabolism of Microbacterium ammoniaphilum, a bacterium which excretes large quantities of L-glutamic acid into the medium. Biosynthesis from 90% [1-13C]glucose results in relatively high specificity of the label, with [2,4-13C2]glutamate as the major product. The predominant biosynthetic pathway for synthesis of glutamate ...