Development of an LC-MS-MS method for the quantification of taurine derivatives in marine invertebrates.

Sulfur amino acids, such as taurine, hypotaurine, and thiotaurine, were found in high quantities in tissues of marine symbiotic organisms (e.g., bivalves, tubeworms) living close to hydrothermal vent sites. Therefore, they are assumed to play a key role in the S-oxidizing base metabolism or sulfide detoxification. We propose here a specific, rapid, and original analytical procedure for the direct determination of sulfur amino acids at the level of a few parts per billion in biological samples, avoiding the classical low specific post-column ortho-phthaldialdehyde derivatization step required by non-ultraviolet-absorbing molecules. Indeed, by coupling liquid chromatography on a porous graphitic stationary phase under isocratic conditions (10 mM ammonium acetate buffer adjusted to pH 9.3) to tandem mass spectrometry (ionization process by pneumatically assisted electrospray in negative ion mode), it is possible to perform specific quantification of these metabolites in less than 10 min directly in biological matrices without any derivatization step or other tedious sample treatments. Thus, taurine, hypotaurine, and thiotaurine have been identified and assayed in several deep sea organisms, showing that the developed method is well suited for this kind of application

Parameter optimization for the analysis of underivatized protein amino acids by liquid chromatography and ionspray tandem mass spectrometry

International audienc

Physicochemical and crystallographic evidence for polymorphism of the racemic ethyl (2-chloromethyl-2,3-dihydro-5H-oxazolo [3,2-a]pyrimidin-5-one)-6-carboxylate

no abstrac

Physicochemical and crystallographic evidence for polymorphism of the racemic ethyl (2-chloromethyl-2,3-dihydro-5H-oxazolo [3,2-a]pyrimidin-5-one)-6-carboxylate

no abstrac

Physicochemical and crystallographic evidence for polymorphism of the racemic ethyl (2-chloromethyl-2,3-dihydro-5H-oxazolo [3,2-a]pyrimidin-5-one)-6-carboxylate

International audienceno abstrac

A Large Antenna Array for Ka-band Satcom-on-the-Move Applications - Accurate Modelling and Experimental Characterization

International audienc

Correlative Analysis of Fluorescent Phytoalexins by Mass Spectrometry Imaging and Fluorescence Microscopy in Grapevine Leaves

International audiencePlant response to their environment stresses is a complex mechanism involving secondary metabolites. Stilbene phytoalexins, namely resveratrol, pterostilbene, piceids and viniferins play a key role in grapevine (Vitis vinifera) leaf defense. Despite their well-established qualities, conventional analyses such as HPLC-DAD or LC-MS lose valuable information on metabolite localization during the extraction process. To overcome this issue, a correlative analysis combining mass spectroscopy imaging (MSI) and fluorescence imaging was developed to localize in situ stilbenes on the same stressed grapevine leaves. High-resolution images of the stilbene fluorescence provided by macroscopy were supplemented by specific distributions and structural information concerning resveratrol, pterostilbene, and piceids obtained by MSI. The two imaging techniques led to consistent and complementary data on the stilbene spatial distribution for the two stresses addressed: UV-C irradiation and infection by Plasmopara viticola. Results emphasize that grapevine leaves react differently depending on the stress. A rather uniform synthesis of stilbenes is induced after UV-C irradiation, whereas a more localized synthesis of stilbenes in stomata guard cells and cell walls is induced by P. viticola infection. Finally, this combined imaging approach could be extended to map phytoalexins of various plant tissues with resolution approaching the cellular level