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Journal of the American Chemical Society Mar 1947
Topics: Arabinose
PubMed: 20289468
DOI: 10.1021/ja01195a517 -
The British Journal of Nutrition Sep 2022Dietary interventions to delay carbohydrate digestion or absorption can effectively prevent hyperglycaemia in the early postprandial phase. L-arabinose can specifically... (Randomized Controlled Trial)
Randomized Controlled Trial
Dietary interventions to delay carbohydrate digestion or absorption can effectively prevent hyperglycaemia in the early postprandial phase. L-arabinose can specifically inhibit sucrase. It remains to be assessed whether co-ingestion of L-arabinose with sucrose delays sucrose digestion, attenuates subsequent glucose absorption and impacts hepatic glucose output. In this double-blind, randomised crossover study, we assessed blood glucose kinetics following ingestion of a 200-ml drink containing 50 g of sucrose with 7·5 g of L-arabinose (L-ARA) or without L-arabinose (CONT) in twelve young, healthy participants (24 ± 1 years; BMI: 22·2 ± 0·5 kg/m). Plasma glucose kinetics were determined by a dual stable isotope methodology involving ingestion of (U-C)-glucose-enriched sucrose, and continuous intravenous infusion of (6,6-H)-glucose. Peak glucose concentrations reached 8·18 ± 0·29 mmol/l for CONT 30 min after ingestion. In contrast, the postprandial rise in plasma glucose was attenuated for L-ARA, because peak glucose concentrations reached 6·62 ± 0·18 mmol/l only 60 min after ingestion. The rate of exogenous glucose appearance for L-ARA was 67 and 57 % lower compared with CONT at t = 15 min and 30 min, respectively, whereas it was 214 % higher at t = 150 min, indicating a more stable absorption of exogenous glucose for L-ARA compared with CONT. Total glucose disappearance during the first hour was lower for L-ARA compared with CONT (11 ± 1 . 17 ± 1 g, < 0·0001). Endogenous glucose production was not differentially affected at any time point ( = 0·27). Co-ingestion of L-arabinose with sucrose delays sucrose digestion, resulting in a slower absorption of sucrose-derived glucose without causing adverse effects in young, healthy adults.
Topics: Male; Adult; Humans; Female; Glucose; Blood Glucose; Arabinose; Cross-Over Studies; Sucrose; Insulin; Eating; Postprandial Period
PubMed: 34657640
DOI: 10.1017/S0007114521004153 -
Angewandte Chemie (International Ed. in... Feb 2019This work reports the one-pot enzymatic cascade that completely converts l-arabinose to l-ribulose using four reactions catalyzed by pyranose 2-oxidase (P2O), xylose...
This work reports the one-pot enzymatic cascade that completely converts l-arabinose to l-ribulose using four reactions catalyzed by pyranose 2-oxidase (P2O), xylose reductase, formate dehydrogenase, and catalase. As wild-type P2O is specific for the oxidation of six-carbon sugars, a pool of P2O variants was generated based on rational design to change the specificity of the enzyme towards the oxidation of l-arabinose at the C2-position. The variant T169G was identified as the best candidate, and this had an approximately 40-fold higher rate constant for the flavin reduction (sugar oxidation) step, as compared to the wild-type enzyme. Computational calculations using quantum mechanics/molecular mechanics (QM/MM) molecular dynamics (MD) showed that this improvement is due to a decrease in the steric effects at the axial C4-OH of l-arabinose, which allows a reduction in the distance between the C2-H and flavin N5, facilitating hydride transfer and enabling flavin reduction.
Topics: Aldehyde Reductase; Arabinose; Biocatalysis; Carbohydrate Dehydrogenases; Catalase; Formate Dehydrogenases; Models, Molecular; Molecular Structure; Pentoses
PubMed: 30605256
DOI: 10.1002/anie.201814219 -
Nutrients Dec 2019Obesity and metabolic syndrome (MS) associated with excess calorie intake has become a great public health concern worldwide. L-arabinose, a naturally occurring plant...
Obesity and metabolic syndrome (MS) associated with excess calorie intake has become a great public health concern worldwide. L-arabinose, a naturally occurring plant pentose, has a promising future as a novel food ingredient with benefits in MS; yet the mechanisms remain to be further elucidated. Gut microbiota is recently recognized to play key roles in MS. Molecular hydrogen, an emerging medical gas with reported benefits in MS, can be produced and utilized by gut microbes. Here we show oral L-arabinose elicited immediate and robust release of hydrogen in mice in a dose-and-time-dependent manner while alleviating high-fat-diet (HFD) induced MS including increased body weight especially fat weight, impaired insulin sensitivity, liver steatosis, dyslipidemia and elevated inflammatory cytokines. Moreover, L-arabinose modulated gene-expressions involved in lipid metabolism and mitochondrial function in key metabolic tissues. Antibiotics treatment abolished L-arabinose-elicited hydrogen production independent of diet type, confirming gut microbes as the source of hydrogen. q-PCR of fecal 16S rDNA revealed modulation of relative abundances of hydrogen-producing and hydrogen-consuming gut microbes as well as probiotics by HFD and L-arabinose. Our data uncovered modulating gut microbiota and hydrogen yield, expression of genes governing lipid metabolism and mitochondrial function in metabolic tissues is underlying L-arabinose's benefits in MS.
Topics: Animals; Arabinose; Diet, High-Fat; Gastrointestinal Microbiome; Gene Expression Regulation; Hydrogen; Lipid Metabolism; Male; Metabolic Syndrome; Mice; Mice, Inbred C57BL; Mitochondria
PubMed: 31847305
DOI: 10.3390/nu11123054 -
International Immunopharmacology Jan 2024There is a growing amount of research that highlights the significant involvement of metabolic imbalance and the inflammatory response in the advancement of colitis....
There is a growing amount of research that highlights the significant involvement of metabolic imbalance and the inflammatory response in the advancement of colitis. Arabinose is a naturally occurring bioactive monosaccharide that plays a crucial role in the metabolic processes and synthesis of many compounds in living organisms. However, the more detailed molecular mechanism by which the administration of arabinose alleviates the progression of colitis and its associated carcinogenesis is still not fully understood. In the present study, arabinose is recognized as a significant and inherent protector of the intestinal mucosal barrier through its role in preserving the integrity of tight junctions within the intestines. Also, it is important to note that there is a positive correlation between the severity of inflammatory bowel disease (IBD) and colorectal cancer (CRC), as well as chemically-induced colitis in mice, and lower levels of arabinose in the bloodstream. In two mouse models of colitis, caused by dextran sodium sulfate (DSS) or by spontaneous colitis in IL-10 mice, damage to the intestinal mucosa was reduced by giving the mice arabinose. When arabinose is administrated to model with colitis, it sets off a chain of events that help keep the lysosomes together and stop cathepsin B from being released. During the progression of intestinal epithelial injury, this process blocks myosin light chain kinase (MLCK) from damaging tight junctions and causing mitochondrial dysfunction. In summary, the results of the study have provided evidence supporting the beneficial effects of arabinose in mitigating the progression of colitis. This is achieved through its ability to avoid dysregulation of the intestinal barrier. Consequently, arabinose may hold promise as a therapeutic supplementation for the management of colitis.
Topics: Mice; Animals; Arabinose; Colitis; Inflammatory Bowel Diseases; Tight Junctions; Intestinal Mucosa; Dextran Sulfate; Disease Models, Animal; Mice, Inbred C57BL
PubMed: 37995573
DOI: 10.1016/j.intimp.2023.111188 -
Nature Chemical Biology Jul 2021The L-arabinose-responsive AraC and its cognate P promoter underlie one of the most often used chemically inducible prokaryotic gene expression systems in microbiology...
The L-arabinose-responsive AraC and its cognate P promoter underlie one of the most often used chemically inducible prokaryotic gene expression systems in microbiology and synthetic biology. Here, we change the sensing capability of AraC from L-arabinose to blue light, making its dimerization and the resulting P activation light-inducible. We engineer an entire family of blue light-inducible AraC dimers in Escherichia coli (BLADE) to control gene expression in space and time. We show that BLADE can be used with pre-existing L-arabinose-responsive plasmids and strains, enabling optogenetic experiments without the need to clone. Furthermore, we apply BLADE to control, with light, the catabolism of L-arabinose, thus externally steering bacterial growth with a simple transformation step. Our work establishes BLADE as a highly practical and effective optogenetic tool with plug-and-play functionality-features that we hope will accelerate the broader adoption of optogenetics and the realization of its vast potential in microbiology, synthetic biology and biotechnology.
Topics: AraC Transcription Factor; Arabinose; Escherichia coli; Escherichia coli Proteins; Genetic Engineering; Light
PubMed: 33903769
DOI: 10.1038/s41589-021-00787-6 -
Journal of Bacteriology Feb 2016Glucose is known to inhibit the transport and metabolism of many sugars in Escherichia coli. This mechanism leads to its preferential consumption. Far less is known...
UNLABELLED
Glucose is known to inhibit the transport and metabolism of many sugars in Escherichia coli. This mechanism leads to its preferential consumption. Far less is known about the preferential utilization of nonglucose sugars in E. coli. Two exceptions are l-arabinose and d-xylose. Previous studies have shown that l-arabinose inhibits d-xylose metabolism in Escherichia coli. This repression results from l-arabinose-bound AraC binding to the promoter of the d-xylose metabolic genes and inhibiting their expression. This mechanism, however, has not been explored in single cells. Both the l-arabinose and d-xylose utilization systems are known to exhibit a bimodal induction response to their cognate sugar, where mixed populations of cells either expressing the metabolic genes or not are observed at intermediate sugar concentrations. This suggests that l-arabinose can only inhibit d-xylose metabolism in l-arabinose-induced cells. To understand how cross talk between these systems affects their response, we investigated E. coli during growth on mixtures of l-arabinose and d-xylose at single-cell resolution. Our results showed that mixed, multimodal populations of l-arabinose- and d-xylose-induced cells occurred at intermediate sugar concentrations. We also found that d-xylose inhibited the expression of the l-arabinose metabolic genes and that this repression was due to XylR. These results demonstrate that a strict hierarchy does not exist between l-arabinose and d-xylose as previously thought. The results may also aid in the design of E. coli strains capable of simultaneous sugar consumption.
IMPORTANCE
Glucose, d-xylose, and l-arabinose are the most abundant sugars in plant biomass. Developing efficient fermentation processes that convert these sugars into chemicals and fuels will require strains capable of coutilizing these sugars. Glucose has long been known to repress the expression of the l-arabinose and d-xylose metabolic genes in Escherichia coli. Recent studies found that l-arabinose also represses the expression of the d-xylose metabolic genes. In the present study, we found that d-xylose also represses the expression of the l-arabinose metabolic genes, leading to mixed populations of cells capable of utilizing l-arabinose and d-xylose. These results further our understanding of mixed-sugar utilization and may aid in strain design.
Topics: Arabinose; Escherichia coli; Gene Expression Regulation, Bacterial; Protein Binding; Xylose
PubMed: 26527647
DOI: 10.1128/JB.00709-15 -
Journal of Bacteriology Jan 1982An oxidative pathway by which L-arabinose is converted to alpha-ketoglutarate in crude extracts of Azospirillum brasiliense is demonstrated. Specific activities of...
An oxidative pathway by which L-arabinose is converted to alpha-ketoglutarate in crude extracts of Azospirillum brasiliense is demonstrated. Specific activities of enzymes involved in the pathway were determined, and several pathway intermediates were identified.
Topics: Arabinose; Bacteria; Carbohydrate Dehydrogenases; Ketoglutaric Acids; Soil Microbiology; Sugar Acids
PubMed: 6798025
DOI: 10.1128/jb.149.1.364-367.1982 -
Journal of Bacteriology Nov 1981Mutations in the arabinose transport operons of Escherichia coli K-12 were isolated with the Mu lac phage by screening for cells in which beta-galactosidase is induced...
Mutations in the arabinose transport operons of Escherichia coli K-12 were isolated with the Mu lac phage by screening for cells in which beta-galactosidase is induced in the presence of L-arabinose. Standard genetic techniques were then used to isolate numerous mutations in either of the two transport systems. Complementation tests revealed only one gene, araE, in the low-affinity arabinose uptake system. P1 transduction placed araE between lysA (60.9 min) and thyA (60.5 min) and closer to lysA. The operon of the high-affinity transport system was found to contain two genes: araF, which codes for the arabinose-binding protein, and a new gene, araG. The newly identified gene, araG, was shown by two-dimensional gel electrophoresis to encode a protein which is located in the membrane. Only defects in araG could abolish uptake by the high-affinity system under the conditions we used.
Topics: Arabinose; Bacterial Proteins; Biological Transport; Carrier Proteins; Chromosome Mapping; Escherichia coli; Escherichia coli Proteins; Genes, Bacterial; Genetic Complementation Test; Mutation
PubMed: 7028715
DOI: 10.1128/jb.148.2.472-479.1981 -
Current Topics in Microbiology and... 1988
Review
Topics: Arabinose; Binding Sites; Carrier Proteins; Escherichia coli Proteins; Hydrogen Bonding; Molecular Structure
PubMed: 3058393
DOI: 10.1007/978-3-642-46641-0_5