A re-investigation of the path of carbon in photosynthesis utilizing GC/MS methodology. Unequivocal verification of the participation of octulose phosphates in the pathway

A GC/EIMS/SIM methodology has been developed to re-examine the path of carbon in photosynthesis. Exposing isolated spinach chloroplasts to (13)CO(2 )on a solid support for a defined period followed by quenching and work-up provided a mixture of labelled sugar phosphates. After enzymatic dephosphorylation and derivatization, the Mox-TMS sugars were analysed using the above method. The purpose of the study was to try to calculate the atom% enrichment of (13)C in as many of the individual carbons in each of the derivatized sugars as was practical using diagnostic fragment ions. In the event, only one 45 s experiment provided sufficient data to enable a range of enrichment values to be calculated. This confirmed that D-glycero-D-altro-octulose phosphate was present in the chloroplasts and was heavily labelled in the C4, C5 and C6 positions, in keeping with the hypothesis that it had an inclusive role and a labelling pattern consistent with a new modified pathway of carbon in photosynthesis

Gas chromatographic-mass spectometric method to characterise the transfer of dietary odorous compounds into plasma and milk

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The dispersion state of milk fat influences triglyceride metablism in the rat A13CO2 breath test study

Background Milk fat, which has different structures in the various dairy products, is a major and controversial lipid source in the Western diet. However, information about the digestion fate of milk fat depending on its supramolecular structure for a given composition is scarce. Aim of the study In this study, 13CO2 breath tests were performed with fasted rats force–fed different dairy preparations of similar composition but differing in fat suprastructure in order to highlight differences of general lipid metabolism. Methods Each preparation consisted of a NaCl solution, anhydrous milk fat labelled with a 13C mixed triacylglycerol, casein (as native phosphocaseinate powder with some lactose), and dipalmitoylphosphatidylcholine. Milk fat was either fed (i) unemulsified consecutively to the aqueous phase, or emulsified as (ii) coarse droplets of ∼10 µm covered mainly with the phospholipid, or (iii–iv) fine droplets of ∼1 µm covered mainly with casein, force–fed either in the liquid state or in a semi–crystallized state. 13C abundance in expired air samples was measured by isotope ratio mass spectrometry; results were expressed as 13C enrichment and were submitted to an ANOVA analysis. Results The 13CO2 excretion curves of the unemulsified preparation and the coarse emulsion were similar and presented a sharp peak, both significantly different from the fine emulsion curves characterized by a nearly linear cumulative recovery. The crystalline state of the fine emulsion droplets and the viscosity of these emulsions did not affect significantly their excretion curves. The lipid metabolization (indicated by the 13C recovery) was significantly slower for the fine droplets coated with casein than for the large droplets coated with the phospholipid and the unemulsified fat. For the latter, a single 13C peak rapidly appeared, while for small droplets coated with caseins, 13C excretion was continuous up to 6 h. Conclusions Global lipid metabolism based on oxidation to CO2 was decreased with smaller compared to larger emulsified milk fat particles with different coatings. These data support the concept that dairy products with different fat suprastructures are digested and metabolized differently

Gas chromatographic-mass spectometric method to characterise the transfer of dietary odorous compounds into plasma and milk

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A51 - Isotopes stables et GC-MS - Transformation de l'acide l-malique 13C par les bacteries lactiques du vin

ISSN: 0365-4877International audienceLes nouvelles recherches sur le theme de la Fermentation Malolactique (FML) s'orientent vers la selection des souches de bacteries pour l'ensemencement des vins. Cette selection passe par l'approfondissement de la connaissance des voies metaboliques de degradation de l'acide 1-malique par les bacteries lactiques au cours de la FML.Pour cela, le devenir de l'acide 1-malique 3.4-13C et l'incorporation de 13C sur le carbone 3 des acides lactique et pyruvique, ont ete suivis au cours de l'incubation en milieu de culture.La methodologie des amas d'ions a ete mise en oeuvre par incubation d'un melange equimoleculaire d'acide 1-malique et 1-malique 3.4-13C, (Ctotale: 22 mM) en milieu de culture (25 ml) pour 4 souches (Lc. oenos B1, B16, 13A1 et Lb. plantarum). La consommation d'acide malique et la production d'acide lactique ont ete mesurees au cours de l'incubation sur des aliquotes (400 μl) prelevees dans chacun des pots, avant incubation (t0) et a t = 5H, 9H, 17H, 24H, 43H et 69H par GC-MS des derives Tms de l'acide malique et de l'acide lactique. Parallelement les facteurs d'enrichissement (FE) ont ete mesures par fragmentometrie de masse sur les ions M * - 15 et M - 15 des acides malique (m/z: 337 et 335) et lactique (m/z: 220 et 219), et de l'acide pyruvique sous forme de derive oxime-Tms (m/z: 248 et 247). Concernant la souche Lc. oenos B1 la production d'acide lactique est symetrique a la consommation de l'acide malique entre 0 et 43H (pente = 0.299 + 0.064 et - 0.254 + 0.041).L'accroissement du facteur d'enrichissement (FE) de l'acide lactique est lineaire entre 0 et 43H puis atteint un plateau pour Lc. oenos, et egalement lineaire entre 0 et 13H puis decroit jusqu'a 69H pour Lb. plantarum, tandis que celui de l'acide malique reste stable, indiquant une consommation identique des molecules non marquees et marquees. Les pentes des droites de correlation de l'evolution du FE de l'acide lactique en fonction du temps montrent des vitesses differentes d'entree du 13C dans l'acide lactique pour chacune des souches, ce parametre pouvant ainsi constituer un critere de differenciation.D'autre part le FE de l'acide pyruvique montre un tres faible accroissement au cours du temps, sauf pour Lb. plantarum (max. = 8%) suggerant que l'acide pyruvique intervient comme intermediaire metabolique dans la transformation de l'acide malique en acide lactique

Preparation of NHC borane complexes by lewis base exchange with amine- and phosphine-boranes

A versatile new method for the preparation of NHC boranes starting from two stable, readily available reactants-an heterocyclic salt and an amine or phosphine-borane-is reported. It uses a Lewis base exchange at boron and provides easy access to new NHC boranes, in particular B-substituted borane ones. © 2010 American Chemical Society

Physical and mental health burden in cases of bipolar disorder classified as current, former, or non-tobacco smokers

International audienceBACKGROUND:Tobacco smoking increases the global burden of bipolar disorder (BD). We examined markers of physical and mental health that are associated with tobacco smoking, controlling for confounders that have not always been considered in previous studies of BD.METHODS:Over 600 individuals with BD I or II referred to the French Network for bipolar disorder (FACE-BD) who completed standardized assessments, and could be reliably classified as current (CS) or former smokers (FS), were compared with those who were never smokers (NS) on: BD symptom load and psychiatric comorbidities; prevalence of alcohol and substance use disorders (ASUD); medication usage; functioning and physical health parameters. The bivariate and multivariate analyses took into account age and gender.RESULTS:300 cases (49%) were CS, 78 (13%) FS and 238 (39%) had never smoked. Rates were similar across genders regardless of BD subtype. Compared with NS, CS were more likely to have an ASUD (Odds Ratio (OR) 5.18), BD I (OR 2.09), and lower abdominal obesity (OR 0.97), and FS were more likely to have an ASUD (OR 6.32) and higher abdominal obesity (OR 1.03).LIMITATIONS:The sample comprised of white Europeans; the FS subgroup was relatively small and we did not apply any statistical correction for the bivariate analyses.CONCLUSIONS:The increased risk of physical and mental health burden in CS and FS compared to NS represents avoidable morbidity in BD. This study offers support to the argument that individuals with BD should be routinely offered support to prevent or stop tobacco smoking

Caractérisation des mécanismes impliqués dans les altérations métaboliques liées à la prise de poids au cours d’un protocole de surnutrition chez l’homme

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Influence of fat emulsification on postprandial lipemia and lipid oxidation in lean and obese subjects

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