COMPARATIVE ANALYSIS OF THE CHANGES OF THE MASS MOMENTS OF INERTIA DURING A BREAST-STROKE

A new method of investigation of athletes' motion takes into consideration the changes of the principal moments of inertia and their directions during the interval of the motion, because these characterise the efficiency and the neuro-muscular regulation of the motion. This paper presents a comparative analysis of two top swimmers (Swl=Rozsa, Sw2=Guttler) and points out the significant difference caused by their alternate motion pattern

Analogy in selenium enrichment and selenium speciation between selenized yeast Saccharomyces cerevisiae and Hericium erinaceus (lion's mane mushroom)

International audienceHuman selenium supplementation is vastly dominated by selenized yeasts based products not only due to regulation issues but due to the fact that yeasts convert inorganic selenium into organic forms up to 2000 μg g-1 through a well characterized selenium metabolism. Though both yeasts and the higher mushroom Agaricomycetes belong to the kingdom of fungi, their selenometabolic pathways are different. Agaricomycetes, the most widely researched higher fungi tend to store the excess of selenium in inorganic forms. A sample of Hericium erinaceus (lion's mane mushroom), also belonging to Agaricomycetes, was examined in our study after moderate selenium enrichment from inorganic selenium source. Enzymatic digestion and ion-pairing chromatography coupled to ICP-MS revealed that nearly 50% of the selenium was in organic forms: selenomethionine and Se-methylselenocysteine. To explore the background of this, directed orthogonal chromatographic purification was executed in search for Se-adenosyl compounds, typical for yeast metabolism. After HPLC-ESI-QTOFMS analyses three Se-adenosyl-compounds were identified: Se-methyl-5-selenoadenosine, Se-methyl-5-selenoadenosine-Se-oxide and the previously unreported Se-dimethyl-5-selenonium-adenosine. Two of these species have been linked only to the selenium metabolism of yeasts. The high selenomethionine content and the presence of Se-adenosyl compounds in Hericium erinaceus open the possibility for a functional food alternative to selenized yeast based dietary supplements. © 2015 Elsevier Ltd

The Use of Ion Mobility Mass Spectrometry for Isomer Composition Determination Extracted from Se-Rich Yeast

peer reviewedThe isomer ratio determination of a selenium-containing metabolite produced by Se-rich yeast was performed. Electrospray Ionization and Ion Mobility Mass Spectrometry (IM-MS) were unsuccessfully used in order to resolve the isomers according to their Collisional Cross Section (CCS) difference. The isomer ratio determination of 2,3-dihydroxypropionylselenocystathionine was performed after multidimensional liquid chromatography preconcentration from a water extract of Se-rich yeast using preparative size exclusion, anion exchange and capillary reverse phase columns coupled to IM-MS. 4’-nitrobenzo-15-crown-5 ether, a Selective Shift Reagent (SSR), was added after the last chromatographic dimension in order to specifically increase the CCS of one of the isomers by the formation of a stable host-guest system with the crown-ether . Both isomers were consequently fully resolved by IM-MS and the relative ratio of the isomers was determined: 11-13% and 87-89%. The present data compared favorably with literature to support the analytical strategy despite the lack of authentic standard for method validation. In addition, computational chemistry methods were successfully applied to design the SSR and to support the experimental data