Centennial-scale atmospheric CO rise increased photosynthetic efficiency in a tropical tree species.

Tropical forests substantially influence the terrestrial carbon sink. Their contributions to the forest carbon sink may increase due to the stimulation of photosynthesis by rising atmospheric CO (C); however, the magnitude of this effect is poorly quantified for tropical canopy trees. We measured the ratio of two deuterium isotopomers of glucose derived from tree rings to estimate how photosynthetic efficiency (photorespiration-to-photosynthesis ratio) has responded to C rise at a centennial scale.

Small molecules dominate organic phosphorus in NaOH-EDTA extracts of soils as determined by P NMR.

Understanding the composition of organic phosphorus (P) in soils is relevant to various disciplines, from agricultural sciences to ecology. Despite past efforts, the precise nature of soil organic P remains an enigma, especially that of the orthophosphate monoesters, which dominate P NMR spectra of NaOH-EDTA extracts of soils worldwide. The monoester region often exhibits an unidentified, broad background believed to represent high molecular weight (MW) P.

Biomarkers for cheese authentication by detailed and fast gas chromatographic profiling of triacylglycerol fatty acids.

Unsaturated fatty acid isomers and odd- and branched-chain fatty acids (OBCFAs) in milk triacylglycerols (TAGs) can be quantitated using gas chromatography (GC), providing access to biomarkers of animal species, breeds, diet, geographic origin, and environmental conditions. Such analysis requires expensive cyanopropyl siloxane or ionic liquid columns of at least 50 m in length, which increases the elution time. Aiming to use GC for cheese authentication and characterization while keeping the experiment time short and maintaining a good separation between fatty acid (FA) isomers, we considered using a 30 m polyethylene glycol-2-nitroterephthalate column.

Cheese characterization and authentication through lipid biomarkers obtained by high-resolution H NMR profiling.

Food quality and safety are at the heart of consumers' concerns across the world. Dairy products, because of their large consumption, are fertile ground for fraudulent acts. This fact justifies the development of effective, accessible, and rapid analytical methods for their authentication.

High-resolution H NMR profiling of triacylglycerols as a tool for authentication of food from animal origin: Application to hen egg matrix.

Metabolomics of complex biological matrices conducted by means of H NMR leads to spectra suffering from severe signal overlapping. Previously, we have developed a high-resolution spectral treatment method to help solving this issue in H NMR of triacylglycerols. In this work, we tested the potential of the developed method in the characterization and authentication of food products from animal origin using egg yolk as a model matrix.

A precise and rapid isotopomic analysis of small quantities of cholesterol at natural abundance by optimized H-C 2D NMR.

Cholesterol, the principal zoosterol, is a key metabolite linked to several health complications. Studies have shown its potential as a metabolic biomarker for predicting various diseases and determining food origin. However, the existing INEPT (insensitive nuclei enhanced by polarization transfer) C position-specific isotope analysis method of cholesterol by NMR was not suitable for very precise analysis of small quantities due to its long acquisition time and therefore is restricted to products rich in cholesterol.