The Experts below are selected from a list of 318 Experts worldwide ranked by ideXlab platform
Hans Schnyder - One of the best experts on this subject based on the ideXlab platform.
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Pre-anthesis reserve utilization for protein and Carbohydrate synthesis in grains of wheat
Plant Physiology, 1999Co-Authors: Thomas Gebbing, Hans SchnyderAbstract:We assessed the contribution of pre-anthesis reserve C to protein and Carbohydrate deposition in grains of wheat (Triticum aestivum L.) using a new approach comprised of steady-state 13C/12C labeling and separation of the protein and Carbohydrate fractions of mature grains. Experiments were performed with two spring wheat cultivars (Kadett and Star) grown with differential N fertilizer supply over 2 years. Pre-anthesis reserves contributed between 30% and 47% of the C in protein and 8% to 27% of the C in Carbohydrates of grains. Partitioning of pre-anthesis C among the grain fractions was strongly dependent on the C/N (w/w) ratio in mobilized pre-anthesis biomass (r2 = 0.92). There appeared to be no significant exchange of pre-anthesis C between amino acids and Carbohydrates during redistribution. The mean apparent efficiency of mobilized Carbohydrate-C use in grain filling (MECHO, estimated as the mass of pre-anthesis C deposited in grain Carbohydrates per gram of pre-anthesis C mobilized from Carbohydrates in vegetative plant parts) was 0.72, whereas that of protein-C (MEP) was 0.56. However, MEP and MECHO varied among treatments. MECHO increased with increasing contributions of water-soluble Carbohydrates to total pre-anthesis Carbohydrate mobilization. MEP decreased with increasing residence time of protein in vegetative biomass. Possible causes for variability of MEP and MECHO are discussed.
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Pre-Anthesis Reserve Utili izat'on for Proten and Carbohydrate Synthesis 'n Grains of VVheat'
1999Co-Authors: Thomas Gebbing, Hans SchnyderAbstract:We assessed the contribution of pre-anthesis reserve C to protein and Carbohydrate deposition in grains of wheat (Triticum aestivum L.) using a new approach comprised of steady-state 13C/12C labeling and separation of the protein and Carbohydrate fractions of mature grains. Experiments were performed with two spring wheat cultivars (Kadett and Star) grown with differential N fertilizer supply over 2 years. Pre-anthesis reserves contributed between 30% and 47% of the C in protein and 8% to 27% of the C in Carbohydrates of grains. Partitioning of pre-anthesis C among the grain fractions was strongly dependent on the C/N (w/w) ratio in mobilized preanthesis biomass (r2 = 0.92). There appeared to be no significant exchange of pre-anthesis C between amino acids and Carbohydrates during redistribution. The mean apparent efficiency of mobilized Carbohydrate-C use in grain filling (MECHO, estimated as the mass of pre-anthesis C deposited in grain Carbohydrates per gram of preanthesis C mobilized from Carbohydrates in vegetative plant parts) was 0.72, whereas that of protein-C (MEp) was 0.56. However, MEp and MECHO varied among treatments. MECHo increased with increasing contributions of water-soluble Carbohydrates to total preanthesis Carbohydrate mobilization. ME, decreased with increasing residence time of protein in vegetative biomass. Possible causes for variability of MEp and MECHO are discussed.
Peter H. Seeberger - One of the best experts on this subject based on the ideXlab platform.
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Carbohydrates in supramolecular chemistry
Chemical Reviews, 2016Co-Authors: Martina Delbianco, Priya Bharate, Silvia Varelaaramburu, Peter H. SeebergerAbstract:Carbohydrates are involved in a variety of biological processes. The ability of sugars to form a large number of hydrogen bonds has made them important components for supramolecular chemistry. We discuss recent advances in the use of Carbohydrates in supramolecular chemistry and reveal that Carbohydrates are useful building blocks for the stabilization of complex architectures. Systems are presented according to the scaffold that supports the glyco-conjugate: organic macrocycles, dendrimers, nanomaterials, and polymers are considered. Glyco-conjugates can form host–guest complexes, and can self-assemble by using Carbohydrate–Carbohydrate interactions and other weak interactions such as π–π interactions. Finally, complex supramolecular architectures based on Carbohydrate–protein interactions are discussed.
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Cantilever array sensors detect specific Carbohydrate-protein interactions with picomolar sensitivity.
ACS Nano, 2011Co-Authors: Kathrin Gruber, Tim Horlacher, Riccardo Castelli, Andreas Mader, Peter H. Seeberger, Bianca A. HermannAbstract:Advances in Carbohydrate sequencing technologies have revealed the tremendous complexity of the glycome. This complexity reflects the structural and chemical diversity of Carbohydrates and is greater than that of proteins and oligonucleotides. The next step in understanding the biological function of Carbohydrates requires the identification and quantification of Carbohydrate interactions with other biomolecules, in particular, with proteins. To this end, we have developed a cantilever array biosensor with a self-assembling Carbohydrate-based sensing layer that selectively and sensitively detects Carbohydrate−protein binding interactions. Specifically, we examined binding of mannosides and the protein cyanovirin-N, which binds and blocks the human immunodeficiency virus (HIV). Cyanovirin-N binding to immobilized oligomannosides on the cantilever resulted in mechanical surface stress that is transduced into a mechanical force and cantilever bending. The degree and duration of cantilever deflection correlat...
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applications of synthetic Carbohydrates to chemical biology
Current Opinion in Chemical Biology, 2010Co-Authors: Bernd Lepenies, Peter H. Seeberger, Jian YinAbstract:Access to synthetic Carbohydrates is an urgent need for the development of Carbohydrate-based drugs, vaccines, adjuvants as well as novel drug delivery systems. Besides traditional synthesis in solution, synthetic Carbohydrates have been generated by chemoenzymatic methods as well as automated solid-phase synthesis. Synthetic oligosaccharides have proven to be useful for identifying ligands of Carbohydrate-binding proteins such as C-type lectins and siglecs using glycan arrays. Furthermore, glyconanoparticles and glycodendrimers have been used for specific targeting of lectins of the immune system such as selectins, DC-SIGN, and CD22. This review focuses on how diverse Carbohydrate structures can be synthetically derived and highlights the benefit of synthetic Carbohydrates for glycobiology.
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Detection of Bacteria with Carbohydrate-Functionalized Fluorescent Polymers
Journal of the American Chemical Society, 2004Co-Authors: Matthew D. Disney, Juan Zheng, Timothy M. Swager, Peter H. SeebergerAbstract:Many pathogens that infect humans use cell surface Carbohydrates as receptors to facilitate cell−cell adhesion. The hallmark of these interactions is their multivalency, or the simultaneous occurrence of multiple interactions. We have used a Carbohydrate-functionalized fluorescent polymer, which displays many Carbohydrate ligands on a single polymer chain, to allow for multivalent detection of pathogens. Incubation of a mannose-functionalized polymer with Escherichia coli yields brightly fluorescent aggregates of bacteria. These results show that Carbohydrate-functionalized fluorescent polymers are a versatile detection method for bacteria. Future design of detectors for other pathogens only requires information on the Carbohydrates bound by the organisms, which has been exhaustively reported in the literature.
Thomas Gebbing - One of the best experts on this subject based on the ideXlab platform.
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Pre-anthesis reserve utilization for protein and Carbohydrate synthesis in grains of wheat
Plant Physiology, 1999Co-Authors: Thomas Gebbing, Hans SchnyderAbstract:We assessed the contribution of pre-anthesis reserve C to protein and Carbohydrate deposition in grains of wheat (Triticum aestivum L.) using a new approach comprised of steady-state 13C/12C labeling and separation of the protein and Carbohydrate fractions of mature grains. Experiments were performed with two spring wheat cultivars (Kadett and Star) grown with differential N fertilizer supply over 2 years. Pre-anthesis reserves contributed between 30% and 47% of the C in protein and 8% to 27% of the C in Carbohydrates of grains. Partitioning of pre-anthesis C among the grain fractions was strongly dependent on the C/N (w/w) ratio in mobilized pre-anthesis biomass (r2 = 0.92). There appeared to be no significant exchange of pre-anthesis C between amino acids and Carbohydrates during redistribution. The mean apparent efficiency of mobilized Carbohydrate-C use in grain filling (MECHO, estimated as the mass of pre-anthesis C deposited in grain Carbohydrates per gram of pre-anthesis C mobilized from Carbohydrates in vegetative plant parts) was 0.72, whereas that of protein-C (MEP) was 0.56. However, MEP and MECHO varied among treatments. MECHO increased with increasing contributions of water-soluble Carbohydrates to total pre-anthesis Carbohydrate mobilization. MEP decreased with increasing residence time of protein in vegetative biomass. Possible causes for variability of MEP and MECHO are discussed.
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Pre-Anthesis Reserve Utili izat'on for Proten and Carbohydrate Synthesis 'n Grains of VVheat'
1999Co-Authors: Thomas Gebbing, Hans SchnyderAbstract:We assessed the contribution of pre-anthesis reserve C to protein and Carbohydrate deposition in grains of wheat (Triticum aestivum L.) using a new approach comprised of steady-state 13C/12C labeling and separation of the protein and Carbohydrate fractions of mature grains. Experiments were performed with two spring wheat cultivars (Kadett and Star) grown with differential N fertilizer supply over 2 years. Pre-anthesis reserves contributed between 30% and 47% of the C in protein and 8% to 27% of the C in Carbohydrates of grains. Partitioning of pre-anthesis C among the grain fractions was strongly dependent on the C/N (w/w) ratio in mobilized preanthesis biomass (r2 = 0.92). There appeared to be no significant exchange of pre-anthesis C between amino acids and Carbohydrates during redistribution. The mean apparent efficiency of mobilized Carbohydrate-C use in grain filling (MECHO, estimated as the mass of pre-anthesis C deposited in grain Carbohydrates per gram of preanthesis C mobilized from Carbohydrates in vegetative plant parts) was 0.72, whereas that of protein-C (MEp) was 0.56. However, MEp and MECHO varied among treatments. MECHo increased with increasing contributions of water-soluble Carbohydrates to total preanthesis Carbohydrate mobilization. ME, decreased with increasing residence time of protein in vegetative biomass. Possible causes for variability of MEp and MECHO are discussed.
Stéphane Panserat - One of the best experts on this subject based on the ideXlab platform.
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Regulation by dietary Carbohydrates of intermediary metabolism in liver and muscle of two isogenic lines of rainbow trout
Frontiers in Physiology, 2018Co-Authors: Xuerong Song, Lucie Marandel, Sandrine Cassy, Geneviève Corraze, Mathilde Dupont-nivet, Edwige Quillet, Inge Geurden, Stéphane PanseratAbstract:Rainbow trout (Oncorhynchus mykiss) is recognized as a typical “glucose-intolerant” fish, and the limits of dietary Carbohydrate utilization have been investigated for many years. In this study, the objective was to test the molecular effects of dietary Carbohydrates on intermediary metabolism in two major metabolic tissues, liver and muscle. Another objective was also to study if the response to Carbohydrate intake depended on the genetic background. We fed two isogenic lines of rainbow trout (named A22h and N38h) with high Carbohydrate diet (Carbohydrate, 22.9%) or low Carbohydrate diet (Carbohydrate, 3.6%) for 12 weeks. Carbohydrates were associated with higher feed utilization owned by the well-known protein-sparing effect, with better fish growth performance. However, atypical regulation of glycolysis and gluconeogenesis in liver and absence of hk and glut4 induction in muscle, were also observed. Regarding the effects of Carbohydrates on other metabolism, we observed an increased, at a molecular level, of hepatic cholesterol biosynthesis, fatty acid oxidation and mitochondrial energy metabolism. Genetic variability (revealed by the differences between the two isogenic lines) was observed for some metabolic genes especially for those involved in the EPA and DHA biosynthetic capacity. Finally, our study demonstrates that dietary Carbohydrate not only affect glucose metabolism but also strongly impact the lipid and energy metabolism in liver and muscle of trout.
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The role of hepatic, renal and intestinal gluconeogenic enzymes in glucose homeostasis of juvenile rainbow trout
Journal of Comparative Physiology B, 2008Co-Authors: S. Kirchner, Stéphane Panserat, P.l. Lim, Sadasivam Kaushik, R.p. FerrarisAbstract:Rainbow trout is unable to utilize high levels of dietary Carbohydrates and experiences hyperglycemia after consumption of Carbohydrate-rich meals. Carbohydrates stimulate hepatic glycolytic activity, but gene expression of the rate-limiting gluconeogenic enzymes glucose-6-phosphatase (G6Pase), fructose-1,6-bisphosphatase (FBPase) and phosphoenolpyruvate carboxykinase (PEPCK) remains high. Although there is significant mRNA expression and activity of gluconeogenic enzymes in trout intestine and kidney, the regulation of these enzymes by diet is not known. We tested the hypothesis that dietary Carbohydrate modulates intestinal and renal G6Pase, FBPase and PEPCK. Fish were either fasted or fed isocaloric Carbohydrate-free (CF) or high Carbohydrate (HC) diets for 14 days. As expected, fish fed HC exhibited postprandial hyperglycemia and enhanced levels of hepatic glucokinase mRNA and activity. Dietary Carbohydrates had no significant effect on the expression and activity of PEPCK, FBPase and G6Pase in all three organs. In contrast, fasting enhanced the activity, but not the mRNA expression of both hepatic and intestinal PEPCK, as well as intestinal FBPase. Therefore, the activity of rate-limiting gluconeogenic enzymes in trout can be modified by fasting, but not by the Carbohydrate content of the diet, potentially causing hyperglycemia when fed high levels of dietary Carbohydrates. In this species consuming low Carbohydrate diets at infrequent intervals in the wild, fasting-induced increases in hepatic and intestinal gluconeogenic enzyme activities may be a key adaptation to prevent perturbations in blood glucose during food deprivation.
Samantha J King - One of the best experts on this subject based on the ideXlab platform.
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pneumococcal Carbohydrate transport food for thought
Trends in Microbiology, 2012Co-Authors: Carolyn M Buckwalter, Samantha J KingAbstract:Streptococcus pneumoniae relies exclusively on Carbohydrates as a carbon source and devotes 30% of all transport mechanisms to Carbohydrate import. Pneumococci utilize at least 32 Carbohydrates in vitro. However, some proposed substrates are not human-derived, so it is unclear where they are encountered in the host niche, and other substrates remain unidentified. The majority of transporter loci are conserved, arguing against redundancy and instead for distinct roles during pathogenesis. Despite this, expression and regulation of Carbohydrate transporters in vivo remain ill defined. Recent work has also demonstrated that multiple ABC transporters share an ATPase; whether this evolved for genome minimization or for transporter regulation remains unknown. Continued efforts to understand Carbohydrate import may reveal novel vaccine and therapeutic targets and increase our understanding of pneumococcal pathogenesis.