In Vivo Use of 1D and 2D 1H NMR to Examine the Glycosylation of Scopoletin in Duboisia myoporoides Cell Suspensions

International audienceCell suspensions initiated from Duboisia myoporoides–a shrub belonging to the Solanaceae family and being a rich source of tropane alkaloids–previously showed their ability to glycosylate scopoletin into scopolin, which represent coumarins showing health benefits. To investigate the time course of this glycosylation reaction, an in vivo NMR approach was developed using a perfusion system in an 8-mm NMR tube and 1H NMR with 1D and 2D (TOCSY and NOESY) experiments. The time course of metabolic changes could therefore be followed without any labeling

Influence of common preanalytical variations on the metabolic profile of serum samples in biobanks

International audienceA blood pre-centrifugation delay of 24 h at room temperature influenced the proton NMR spectroscopic profiles of human serum. A blood pre-centrifugation delay of 24 h at 4°C did not influence the spectroscopic profile as compared with 4 h delays at either room temperature or 4°C. Five or ten serum freeze-thaw cycles also influenced the proton NMR spectroscopic profiles. Certain common in vitro preanalytical variations occurring in biobanks may impact the metabolic profile of human serum

Osmoregulated trehalose-derived oligosaccharides in Sinorhizobium meliloti

AbstractSinorhizobium meliloti is a soil bacterium accumulating glutamate, N-acetylglutaminyl glutamine amide and trehalose in hyperosmolarity. Besides these compatible solutes, we highlighted several compounds in S. meliloti Rm1021 wild-type strain. The purification and the structural characterization based on liquid chromatography evaporative light scattering detector, electrospray ionization high resolution mass spectrometry and nuclear magnetic resonance techniques showed they were four linear oligosaccharides composed of 3, 4, 5 and 6 glucose units all linked by α-(1→2) linkages except a terminal α-(1↔1) linkage. These oligosaccharides were cytoplasmic and were observed in several wild-type strains suggesting they were common features in S. meliloti strains grown in hyperosmolarity

Use of H-1-NMR metabolomics to precise the function of the third glutamate dehydrogenase gene in Arabidopsis thaliana

It is now well established that the GS/GOGAT cycle is the major route for ammonium assimilation in higher plants. However, it has often been argued that other enzymes, such as glutamate dehydrogenase, have the capacity to assimilate ammonium, leading to the hypothesis that alternative ammonium assimilatory pathways could operate under particular physiological conditions. The GDH enzyme is encoded by two distinct genes, GDH1 and GDH2. A third gene, GDH3, potentially encoding GDH has recently been identified by in silico studies performed on Arabidopsis thaliana. In order to precise its function, the metabolic profile of gdh3 knock out mutants were compared to wild type plants using the 1H-NMR technique. 1H-NMR spectra coupled with principal component analysis and partial least square-discriminant analysis were applied to identify changes of the metabolic profiles. These experiments were performed on roots, leaves and stems. In the gdh3 mutant, metabolic variations were observed for carboxylic acids, amino acids and carbohydrates content

Principles and applications of a controllable electromagnetic band gap material to a conformable spherical radome

This paper presents the principle of two types of conformable and controllable spherical radome based on Electromagnetic Band Gap (EBG) materials operating at around 10 GHz. The EBG structure is composed of a grid of metallic wires conformed on a hollow spherical object. Two switching control configurations are considered: (1) between an EBG structure made of electrically continuous wires and another one made of discontinuous wires, and (2) between two EBG structures made of discontinuous wires where each has a different period of discontinuities. Both switching configurations are simulated and experimentally characterized on passive prototypes. An excellent agreement is observed between simulations and measurements. The radiation patterns of two types of antennas, a horn antenna and a meteorological antenna, are also measured in the presence of the radome

Towards a better understanding of vinylene carbonate derived SEI-layers by synthesis of reduction compounds

Here two chemical reduction pathways to synthesize the vinylene carbonate (VC)and poly(VC)reduction products are investigated, with the precise aim of further deciphering the lithium-ion battery solid electrolyte interphase (SEI)layer composition and the associated reduction mechanisms. The liquid synthesis pathway offers the opportunity of varying the concentration of Li-4,4′-Di-tert-butylbiphenyl reducing agent, whereas the dry synthesis pathway by ball milling allows to solve issues related to solvent-induced side reactions and washing procedure. As a result, the two syntheses do not unveil the same reduction mechanisms, favouring either carboxylate or carbonate salts as the major end product. The latter pathway is very efficient in terms of providing SEI-layers products resulting in well-defined IR spectra and comparisons with simulated spectra enable us to obtain IR fingerprints of the Li di-vinylene di-carbonate (LDVD)compound. Taken together the synthesis procedures provide information on conditions favouring radical polymerization and further poly(VC)reduction into Li 2 CO 3 and polyacetylene. Overall, this chemical simulation of SEI-layers formation assists in a proper characterization of the SEI-layers created on graphite surfaces by their IR spectra showing that Li 2 CO 3 , LDVD and poly(VC)are all present in different proportions dependent on the VC content in the electrolyte

High reactivity of the nickel-rich LiNi1-x-yMnxCoyO2 layered materials surface towards H2O/CO2 atmosphere and LiPF6-based electrolyte

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