¹³C NMR detection of metabolic mixtures enhanced by Dynamic Nuclear Polarization

Dynamic Nuclear Polarization (DNP) shows a high potential to boost the sensitivity of NMR experiments. Particularly promising is the dissolution DNP approach, which can increase the sensitivity of certain liquid-state NMR experiments by factors in excess of 104. Usual applications of this promising technique rely on polarizing a 13C-labeled tracer, and following the latter’s metabolic fate after injection into an MRI scanner. This paper explores a different aspect pertaining the use of hyperpolarized metabolites, with a preliminary report exploring the potential of dissolution DNP in metabolomics analyses. To this end synthetic samples involving several common metabolites were hyperpolarized, and the analytical performance of the ensuing DNP NMR experiment was evaluated under a variety of different experimental conditions. These analyses revealed average signal enhancements of ~5000x to 10000x for non-protonated 13C sites, with a repeatability better than 10% on the 13C NMR peak areas. These are promising results, opening interesting application perspectives in the field of metabolomics analyses of biological extracts.The authors from France thank the French National Research Agency for a young investigator starting grant (ANR Grant 2010-JCJC-0804-01) and the CORSAIRE metabolomics platform from the Biogenouest network. The authors from Israel acknowledge ERC Advanced Grant #246754, EU'S BioNMR Grant #261863, DIP Project 710907 (Ministry of Education and Research, Germany), and the generosity of the Perlman Family Foundation

NMR-based metabolomics highlights differences in plasma metabolites in pigs exhibiting diet-induced differences in adiposity

Purpose : A better understanding of the control of body fat mass and distribution is required for both human health and animal production. The current study investigates plasma parameters in response to changes in body fat mass.[b]Methods[/b] : Pigs from two lines divergently selected for residual feed intake were fed diets contrasted in energy sources and nutrients. Between 74 and 132 days of age, pigs (n = 12 by diet and by line) received isoproteic and isoenergetic diets, either rich in starch (LF) or in lipids and fibres (HF). At the end of the feeding trial, plasma samples were analysed by 1H NMR spectroscopy and standard hormonal and biochemical assays.[b]Results[/b] : Pigs fed the HF diet had lower (P < 0.01) perirenal and subcutaneous adipose tissue relative masses than pigs fed the LF diet. Metabolomic approach showed a clear discrimination between diets, with lower (P < 0.05) plasma levels of creatinine-lysine, creatine, tyrosine, proline, histidine, lysine, phenylalanine and formate but higher (P < 0.001) plasma VLDL-LDL levels in HF pigs than in LF pigs. Plasma concentrations of triglycerides were higher (P < 0.001), while plasma concentrations of β-hydroxybutyrate, leptin, glucose, insulin and urea were lower (P ≤ 0.05) in HF pigs than in LF pigs. Plasma levels of leptin, creatine and urea were positively correlated (r = 0.3, P < 0.05) with relative adipose tissue masses.[b]Conclusion[/b] : These data indicate that metabolites associated with energy and protein metabolism were involved in the response to a high-fat, high-fibre diet. Relevant plasma indicators of metabolic flexibility related to changes in body adiposity were then proposed

Composition corporelle et caractéristiques métaboliques de porcs en croissance à efficacité alimentaire contrastée et nourris avec des régimes plus ou moins riches en fibres et en lipides

JRP session : AlimentationThe ways growing pigs use and partition dietary energy are key elements of their productive efficiency. In the present study, 48 Large White castrated males from two divergent lines selected for residual feed intake were compared for responses to dietary energy source. Between 10 and 20 weeks of age, pigs were fed (n = 12 by diet and by line) two different diets (same metabolizable energy level, same protein content) rich in cereals (LF) or rich in crude fiber sources and oil (HF). In the two lines, daily feed intake and average daily gain were lower when diet HF was fed. As compared with the LF diet, the HF diet also reduced body fatness and intramuscular fat content in both lines, but hepatic lipids were increased specifically in the less efficient line. Triglyceridemia was higher and plasma glucose concentration was lower when pigs were fed the HF diet compared to the LF diet. Metabolomics revealed lower plasma concentrations (‐10 to ‐25%) in creatine, proline, histidine, lysine, tyrosine and phenylalanine in pigs fed the HF diet than in those fed the LF diet. These results suggest that both energy and protein metabolisms are affected by dietary energy sources and that the partition of dietary energy among tissues is dependent on genetics.L’utilisation et la répartition de l’énergie alimentaire sont des éléments importants pour expliquer les variations d’efficience productive des porcs en croissance. Dans cette étude, les réponses de 48 mâles castrés Large White issus de deux lignées divergentes sélectionnées pour la consommation journalière résiduelle ont été comparées en fonction de la source d’énergie dans l’aliment. Entre 10 et 20 semaines d’âge, les porcs ont été nourris (n = 12 par régime et par lignée) avec deux régimes différents (iso‐énergie métabolisable et iso‐protéiques), soit riche en céréales (LF) soit comprenant une proportion élevée de fibres alimentaires et d’huiles (HF). De manière similaire pour les deux lignées, la consommation journalière et la vitesse de croissance sont réduits avec le régime HF comparativement au régime LF. Le régime HF réduit l’adiposité corporelle et la teneur en lipides intramusculaires dans les deux lignées ; il augmente la teneur en lipides hépatiques seulement pour les porcs de la lignée la moins efficace. Pour les deux lignées, la triglycéridémie est plus élevée et la glycémie est réduite avec le régime HF comparativement au régime LF. Une analyse métabolomique révèle des concentrations plasmatiques en créatine, proline, histidine, lysine, tyrosine et phénylalanine de 10 à 25% inférieures avec le régime HF. Cette étude suggère une modification des métabolismes énergétiques et protéiques en réponse aux régimes, et une interaction avec la lignée dans la partition de l’énergie

Composition corporelle et caractéristiques métaboliques de porcs en croissance à efficacité alimentaire contrastée et nourris avec des régimes plus ou moins riches en fibres et en lipides

L’utilisation et la répartition de l’énergie alimentaire sont des éléments importants pour expliquer les variations d’efficience productive des porcs en croissance. Dans cette étude, les réponses de 48 mâles castrés Large White issus de deux lignées divergentes sélectionnées pour la consommation journalière résiduelle ont été comparées en fonction de la source d’énergie dans l’aliment. Entre 10 et 20 semaines d’âge, les porcs ont été nourris (n = 12 par régime et par lignée) avec deux régimes différents (iso‐énergie métabolisable et iso‐protéiques), soit riche en céréales (LF) soit comprenant une proportion élevée de fibres alimentaires et d’huiles (HF). De manière similaire pour les deux lignées, la consommation journalière et la vitesse de croissance sont réduits avec le régime HF comparativement au régime LF. Le régime HF réduit l’adiposité corporelle et la teneur en lipides intramusculaires dans les deux lignées ; il augmente la teneur en lipides hépatiques seulement pour les porcs de la lignée la moins efficace. Pour les deux lignées, la triglycéridémie est plus élevée et la glycémie est réduite avec le régime HF comparativement au régime LF. Une analyse métabolomique révèle des concentrations plasmatiques en créatine, proline, histidine, lysine, tyrosine et phénylalanine de 10 à 25% inférieures avec le régime HF. Cette étude suggère une modification des métabolismes énergétiques et protéiques en réponse aux régimes, et une interaction avec la lignée dans la partition de l’énergie.The ways growing pigs use and partition dietary energy are key elements of their productive efficiency. In the present study, 48 Large White castrated males from two divergent lines selected for residual feed intake were compared for responses to dietary energy source. Between 10 and 20 weeks of age, pigs were fed (n = 12 by diet and by line) two different diets (same metabolizable energy level, same protein content) rich in cereals (LF) or rich in crude fiber sources and oil (HF). In the two lines, daily feed intake and average daily gain were lower when diet HF was fed. As compared with the LF diet, the HF diet also reduced body fatness and intramuscular fat content in both lines, but hepatic lipids were increased specifically in the less efficient line. Triglyceridemia was higher and plasma glucose concentration was lower when pigs were fed the HF diet compared to the LF diet. Metabolomics revealed lower plasma concentrations (‐10 to ‐25%) in creatine, proline, histidine, lysine, tyrosine and phenylalanine in pigs fed the HF diet than in those fed the LF diet. These results suggest that both energy and protein metabolisms are affected by dietary energy sources and that the partition of dietary energy among tissues is dependent on genetics

Hyperpolarized NMR of plant and cancer cell extracts at natural abundance

International audienceNatural abundance C-13 NMR spectra of biological extracts are recorded in a single scan provided that the samples are hyperpolarized by dissolution dynamic nuclear polarization combined with cross polarization. Heteronuclear 2D correlation spectra of hyperpolarized breast cancer cell extracts can also be obtained in a single scan. Hyperpolarized NMR of extracts opens many perspectives for metabolomics

Green Edge ice camp campaigns: understanding the processes controlling the under-ice Arctic phytoplankton spring bloom

International audienceThe Green Edge initiative was developed to investigate the processes controlling the primary productivity and the fate of organic matter produced during the Arctic phytoplankton spring bloom (PSB) and to determine its role in the ecosystem. Two field campaigns were conducted in 2015 and 2016 at an ice camp located on landfast sea ice southeast of Qikiqtarjuaq Island in Baffin Bay (67.4797N, 63.7895W). During both expeditions, a large suite of physical, chemical and biological variables was measured beneath a consolidated sea ice cover from the surface to the bottom at 360 m depth to better understand the factors driving the PSB. Key variables such as temperature, salinity, radiance, irradiance, nutrient concentrations, chlorophyll-a concentration, bacteria, phytoplankton and zooplankton abundance and taxonomy, carbon stocks and fluxes were routinely measured at the ice camp. Here, we present the results of a joint effort to tidy and standardize the collected data sets that will facilitate their reuse in other Arctic studies. The dataset is available at http://www.seanoe.org/data/00487/59892/ (Massicotte et al., 2019a)