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The Journal of Biological Chemistry Nov 1956
Topics: Carbohydrate Metabolism; Hexoses; Pentoses; Seedlings; Triticum
PubMed: 13376596
DOI: No ID Found -
Carbohydrate Research Mar 2018In this work pentose sugar (D-xylose, D-ribose and D-arabinose) gas phase dehydration reaction was investigated by means of mass spectrometric techniques and theoretical...
In this work pentose sugar (D-xylose, D-ribose and D-arabinose) gas phase dehydration reaction was investigated by means of mass spectrometric techniques and theoretical calculations. The ionic species derived from the dehydration reaction of protonated D-ribose and D-arabinose were structurally characterized by their fragmentation patterns and the relative dehydration energies measured by energy resolved CAD mass spectra. The results were compared with those recently obtained for D-xylose in the same mass spectrometric experimental conditions. Dehydration of C1-OH protonated sugars was theoretically investigated at the CCSD(T)/cc-pVTZ//M11/6-311++G(2d,2p) level of theory. Protonated pentoses are not stable and promptly lose a water molecule giving rise to the dehydrated ions at m/z 133. D-xylose, D-ribose and D-arabinose dehydration follows a common reaction pathway with ionic intermediates and transition states characterized by similar structures. Slightly different dehydration energies were experimentally measured and the relative trend was theoretically confirmed. The overall dehydration activation energy follows the order arabinose < ribose < xylose. Gas-phase pentose sugar dehydration leads to the formation of protonated 2-furaldehyde as final product. Based on the experimental and theoretical evidence a new mechanistic hypothesis starting from C1-OH protonation was proposed.
Topics: Arabinose; Dehydration; Mass Spectrometry; Pentoses; Ribose; Sugars; Xylose
PubMed: 29428483
DOI: 10.1016/j.carres.2018.01.007 -
La Presse Medicale Dec 1950
Topics: Carbohydrate Metabolism, Inborn Errors; Pentoses; Sugar Alcohol Dehydrogenases; Xylulose
PubMed: 14808025
DOI: No ID Found -
Biotechnology Advances Nov 2013Interest in thermophilic bacteria as live-cell catalysts in biofuel and biochemical industry has surged in recent years, due to their tolerance of high temperature and... (Review)
Review
Interest in thermophilic bacteria as live-cell catalysts in biofuel and biochemical industry has surged in recent years, due to their tolerance of high temperature and wide spectrum of carbon-sources that include cellulose. However their direct employment as microbial cellular factories in the highly demanding industrial conditions has been hindered by uncompetitive biofuel productivity, relatively low tolerance to solvent and osmic stresses, and limitation in genome engineering tools. In this work we review recent advances in dissecting and engineering the metabolic and regulatory networks of thermophilic bacteria for improving the traits of key interest in biofuel industry: cellulose degradation, pentose-hexose co-utilization, and tolerance of thermal, osmotic, and solvent stresses. Moreover, new technologies enabling more efficient genetic engineering of thermophiles were discussed, such as improved electroporation, ultrasound-mediated DNA delivery, as well as thermo-stable plasmids and functional selection systems. Expanded applications of such technological advancements in thermophilic microbes promise to substantiate a synthetic biology perspective, where functional parts, module, chassis, cells and consortia were modularly designed and rationally assembled for the many missions at industry and nature that demand the extraordinary talents of these extremophiles.
Topics: Bacteria; Biofuels; Carbohydrate Metabolism; Cellulose; Gene Regulatory Networks; Genetic Engineering; Hexoses; Humans; Metabolic Engineering; Pentoses; Synthetic Biology
PubMed: 23510903
DOI: 10.1016/j.biotechadv.2013.03.003 -
Applied and Environmental Microbiology Jan 1993Pentose sugars can be an important energy source for ruminal bacteria, but there has been relatively little study regarding the regulation of pentose utilization and... (Comparative Study)
Comparative Study
Pentose sugars can be an important energy source for ruminal bacteria, but there has been relatively little study regarding the regulation of pentose utilization and transport by these organisms. Selenomonas ruminantium, a prevalent ruminal bacterium, actively metabolizes xylose and arabinose. When strain D was incubated with a combination of glucose and xylose or arabinose, the hexose was preferentially utilized over pentoses, and similar preferences were observed for sucrose and maltose. However, there was simultaneous utilization of cellobiose and pentoses. Continuous-culture studies indicated that at a low dilution rate (0.10 h-1) the organism was able to co-utilize glucose and xylose. This co-utilization was associated with growth rate-dependent decreases in glucose phosphotransferase activity, and it appeared that inhibition of pentose utilization was due to catabolite inhibition by the glucose phosphotransferase transport system. Xylose transport activity in strain D required induction, while arabinose permease synthesis did not require inducer but was subject to repression by glucose. Since an electrical potential or a chemical gradient of protons drove xylose and arabinose uptake, pentose-proton symport systems apparently contributed to transport.
Topics: Animals; Arabinose; Biological Transport; Glucose; Gram-Negative Anaerobic Bacteria; Hexoses; Pentoses; Rumen; Xylose
PubMed: 8439166
DOI: 10.1128/aem.59.1.40-46.1993 -
Biochimica Et Biophysica Acta Jun 1956
Topics: Azotobacter; Azotobacter vinelandii; Nucleic Acids; Pentoses
PubMed: 13341968
DOI: 10.1016/0006-3002(56)90370-5 -
Carbohydrate Research Jun 2014Epimerisation between ribofuranose and arabinofuranose sugars is crucial in several biosynthetic pathways, but is typically challenging to monitor. Here, we have...
Epimerisation between ribofuranose and arabinofuranose sugars is crucial in several biosynthetic pathways, but is typically challenging to monitor. Here, we have screened for fluorescent boronic acids that can be used as molecular probes for the specific detection of ribofuranose over arabinofuranose sugars in solution. We show excellent specificity of the fluorescent response of 3-biphenylboronic acid to ribofuranose at physiological pH. This provides a tool for in situ monitoring of carbohydrate modifying enzymes and provides a viable alternative to traditional radiolabelled assays.
Topics: Arabinose; Boronic Acids; Fluorescence; Hydrogen-Ion Concentration; Molecular Probes; Molecular Structure; Pentoses
PubMed: 24785389
DOI: 10.1016/j.carres.2014.02.007 -
Nature Jan 1953
Topics: Anthracenes; Hexoses; Pentoses; Plants
PubMed: 13025525
DOI: 10.1038/171176a0 -
Physiologia Bohemoslovenica 1956
Topics: Carbohydrate Metabolism; Pentoses
PubMed: 13452856
DOI: No ID Found -
Postepy Biochemii 1956
Topics: Carbohydrate Metabolism; Glycolysis; Pentoses
PubMed: 13453029
DOI: No ID Found