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  Subjects -> CHEMISTRY (Total: 810 journals)
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CHEMISTRY (564 journals)                  1 2 3 4 5 6 | Last

2D Materials     Hybrid Journal   (Followers: 4)
Accreditation and Quality Assurance: Journal for Quality, Comparability and Reliability in Chemical Measurement     Hybrid Journal   (Followers: 31)
ACS Catalysis     Full-text available via subscription   (Followers: 25)
ACS Chemical Neuroscience     Full-text available via subscription   (Followers: 13)
ACS Combinatorial Science     Full-text available via subscription   (Followers: 8)
ACS Macro Letters     Full-text available via subscription   (Followers: 19)
ACS Medicinal Chemistry Letters     Full-text available via subscription   (Followers: 25)
ACS Nano     Full-text available via subscription   (Followers: 337)
ACS Photonics     Full-text available via subscription   (Followers: 6)
ACS Synthetic Biology     Full-text available via subscription   (Followers: 9)
Acta Chemica Iasi     Open Access  
Acta Chimica Sinica     Full-text available via subscription  
Acta Chimica Slovaca     Open Access   (Followers: 6)
Acta Chromatographica     Full-text available via subscription   (Followers: 10)
Acta Facultatis Medicae Naissensis     Open Access   (Followers: 1)
Acta Metallurgica Sinica (English Letters)     Hybrid Journal   (Followers: 5)
adhäsion KLEBEN & DICHTEN     Hybrid Journal   (Followers: 4)
Adhesion Adhesives & Sealants     Hybrid Journal   (Followers: 5)
Adsorption Science & Technology     Full-text available via subscription   (Followers: 10)
Advanced Functional Materials     Hybrid Journal   (Followers: 38)
Advances in Chemical Engineering and Science     Open Access   (Followers: 22)
Advances in Chemical Science     Open Access   (Followers: 9)
Advances in Colloid and Interface Science     Full-text available via subscription   (Followers: 15)
Advances in Drug Research     Full-text available via subscription   (Followers: 16)
Advances in Enzyme Research     Open Access  
Advances in Fluorine Science     Full-text available via subscription   (Followers: 7)
Advances in Fuel Cells     Full-text available via subscription   (Followers: 12)
Advances in Heterocyclic Chemistry     Full-text available via subscription   (Followers: 8)
Advances in Materials Physics and Chemistry     Open Access   (Followers: 16)
Advances in Nanoparticles     Open Access   (Followers: 12)
Advances in Organometallic Chemistry     Full-text available via subscription   (Followers: 9)
Advances in Polymer Science     Hybrid Journal   (Followers: 39)
Advances in Protein Chemistry     Full-text available via subscription   (Followers: 6)
Advances in Protein Chemistry and Structural Biology     Full-text available via subscription   (Followers: 10)
Advances in Quantum Chemistry     Full-text available via subscription   (Followers: 4)
African Journal of Chemical Education     Open Access   (Followers: 1)
African Journal of Pure and Applied Chemistry     Open Access   (Followers: 4)
Afrique Science : Revue Internationale des Sciences et Technologie     Open Access   (Followers: 1)
Agrokémia és Talajtan     Full-text available via subscription   (Followers: 1)
Alchemy     Open Access   (Followers: 3)
Alkaloids: Chemical and Biological Perspectives     Full-text available via subscription   (Followers: 4)
AMB Express     Open Access  
American Journal of Applied Sciences     Open Access   (Followers: 30)
American Journal of Biochemistry and Biotechnology     Open Access   (Followers: 202)
American Journal of Biochemistry and Molecular Biology     Open Access   (Followers: 11)
American Journal of Chemistry     Open Access   (Followers: 18)
American Journal of Plant Physiology     Open Access   (Followers: 10)
American Mineralogist     Full-text available via subscription   (Followers: 7)
Analyst     Full-text available via subscription   (Followers: 35)
Angewandte Chemie     Hybrid Journal   (Followers: 18)
Angewandte Chemie International Edition     Hybrid Journal   (Followers: 263)
Annales UMCS, Chemia     Open Access   (Followers: 2)
Annual Reports in Computational Chemistry     Full-text available via subscription   (Followers: 1)
Annual Reports Section A (Inorganic Chemistry)     Full-text available via subscription   (Followers: 2)
Annual Reports Section B (Organic Chemistry)     Full-text available via subscription   (Followers: 4)
Annual Review of Chemical and Biomolecular Engineering     Full-text available via subscription   (Followers: 10)
Annual Review of Food Science and Technology     Full-text available via subscription   (Followers: 11)
Anti-Infective Agents     Hybrid Journal   (Followers: 1)
Applied Organometallic Chemistry     Hybrid Journal   (Followers: 4)
Applied Spectroscopy     Full-text available via subscription   (Followers: 12)
Applied Surface Science     Hybrid Journal   (Followers: 19)
Arabian Journal of Chemistry     Full-text available via subscription   (Followers: 6)
ARKIVOC     Open Access   (Followers: 1)
Asian Journal of Biochemistry     Open Access   (Followers: 1)
Australian Journal of Chemistry     Hybrid Journal   (Followers: 4)
Autophagy     Full-text available via subscription   (Followers: 1)
Avances en Quimica     Open Access   (Followers: 1)
Biochemical Pharmacology     Hybrid Journal   (Followers: 6)
Biochemistry     Full-text available via subscription   (Followers: 253)
Biochemistry Insights     Open Access   (Followers: 4)
Biochemistry Research International     Open Access   (Followers: 4)
BioChip Journal     Hybrid Journal   (Followers: 1)
Bioinorganic Chemistry and Applications     Open Access   (Followers: 4)
Bioinspired Materials     Open Access  
Biointerface Research in Applied Chemistry     Open Access   (Followers: 1)
Biointerphases     Open Access  
Biomacromolecules     Full-text available via subscription   (Followers: 17)
Biomass Conversion and Biorefinery     Partially Free   (Followers: 5)
Biomedical Chromatography     Hybrid Journal   (Followers: 7)
Biomolecular NMR Assignments     Hybrid Journal   (Followers: 2)
BioNanoScience     Partially Free   (Followers: 4)
Bioorganic & Medicinal Chemistry     Hybrid Journal   (Followers: 30)
Bioorganic & Medicinal Chemistry Letters     Hybrid Journal   (Followers: 24)
Bioorganic Chemistry     Hybrid Journal   (Followers: 5)
Biopolymers     Hybrid Journal   (Followers: 14)
Biosensors     Open Access   (Followers: 3)
Biotechnic and Histochemistry     Hybrid Journal   (Followers: 1)
Boletin de la Sociedad Chilena de Quimica     Open Access  
Bulletin of the Chemical Society of Ethiopia     Open Access   (Followers: 1)
Bulletin of the Chemical Society of Japan     Full-text available via subscription   (Followers: 13)
Canadian Association of Radiologists Journal     Full-text available via subscription   (Followers: 3)
Canadian Journal of Chemistry     Full-text available via subscription   (Followers: 6)
Canadian Mineralogist     Full-text available via subscription   (Followers: 1)
Carbohydrate Research     Hybrid Journal   (Followers: 11)
Carbon     Hybrid Journal   (Followers: 54)
Catalysis for Sustainable Energy     Open Access   (Followers: 2)
Catalysis Reviews: Science and Engineering     Hybrid Journal   (Followers: 5)
Catalysis Science and Technology     Free   (Followers: 4)
Catalysis Surveys from Asia     Hybrid Journal   (Followers: 4)
Catalysts     Open Access   (Followers: 7)

        1 2 3 4 5 6 | Last

Journal Cover Carbohydrate Research     [SJR: 0.675]   [H-I: 77]
   [13 followers]  Follow    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 0008-6215 - ISSN (Online) 0008-6215
   Published by Elsevier Homepage  [2585 journals]
  • Total synthesis of pachastrissamine together with its 4-epi-congener via
           [3,3]-sigmatropic rearrangements and antiproliferative/cytotoxic
           evaluation
    • Abstract: Publication date: 30 January 2015
      Source:Carbohydrate Research, Volume 402
      Author(s): Miroslava Martinková , Eva Mezeiová , Milica Fabišíková , Jozef Gonda , Martina Pilátová , Ján Mojžiš
      Synthesis of the HCl salts of two anhydrophytosphingosines, jaspine B (1) and its 4-epi-congener 5 from easily available dimethyl l-tartrate and/or l-arabinose, is described. The key transformations are the efficient incorporation of a chiral amino group via [3,3]-sigmatropic rearrangements, a Wittig olefination for the instalment of the carbon backbone and the acid-promoted building-up of a tetrahydrofuran framework. Evaluation for in vitro antiproliferative/cytotoxic activity with a panel of human tumour cell lines using a MTT assay revealed for some compounds of our strategy noteworthy activity. Compound 1·HCl (IC50: 0. 41–2.35μM), its antipode ent-1·HCl (IC50: 4.07–5.69μM) and also stereoisomer 4·HCl (IC50: 4.28–6.10μM) exhibited significant potency compared with clinically available anticancer drugs such as cisplatin (IC50: 11.4–14.7μM) and etoposide (IC50: 1.2–21.2μM) on MDA-MB-231, MCF-7 and Jurkat cells.
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      PubDate: 2015-01-27T11:49:39Z
       
  • Recent developments in β-C-glycosides: synthesis and applications
    • Abstract: Publication date: 30 January 2015
      Source:Carbohydrate Research, Volume 402
      Author(s): Krishnamoorthy Lalitha , Kumarasamy Muthusamy , Y. Siva Prasad , Praveen Kumar Vemula , Subbiah Nagarajan
      In the last few years, considerable progress has been made in the synthesis of C-glycosides. Despite its challenging chemistry, due to its versatility, C-glycosides play a pivotal role in developing novel materials, surfactants and bioactive molecules. In this review, we present snapshots of various synthetic methodologies developed for C-glycosides in the recent years and the potential application of C-glycosides derived from β-C-glycosidic ketones.
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      PubDate: 2015-01-27T11:49:39Z
       
  • Stereocontrolled preparation of biotinylated chondroitin sulfate E di-,
           tetra-, and hexasaccharide conjugates
    • Abstract: Publication date: 30 January 2015
      Source:Carbohydrate Research, Volume 402
      Author(s): Jean-Claude Jacquinet , Chrystel Lopin-Bon
      The synthesis of biotinylated conjugates of oligomers of the basic repeating unit of chondroitin sulfate E (CS-E) with the sequence [GlcA-4,6-disulfated GalNAc] n is reported herein for the first time. An efficient and stereocontrolled preparation of di-, tetra-, and hexasaccharide derivatives was achieved using a common key disaccharide intermediate in an iterative way. An unexpected and never reported side reaction on the carbonyl group of the levulinate ester was observed during a coupling reaction. These complex molecules should be useful to study their interactions with various proteins.
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      PubDate: 2015-01-27T11:49:39Z
       
  • Facile access to new C-glycosides and C-glycoside scaffolds incorporating
           functionalised aromatic moieties
    • Abstract: Publication date: 30 January 2015
      Source:Carbohydrate Research, Volume 402
      Author(s): Philip Redpath , Kerry A. Ness , Joanne Rousseau , Simon J.F. Macdonald , Marie E. Migaud
      The tandem ene/intramolecular Sakurai cyclisation (IMSC) reaction has been successfully applied to the synthesis of a range of C-glycosides, with key intermediates offering opportunities for functionalisation of the glycon moiety. To demonstrate the versatility of the approach to access the 2-deoxy-C-glycoside series, we synthesised diastereomerically pure C-glucoside and galactoside derivatives incorporating functionalised aromatic, heteroaromatic and bicyclic aromatic moieties, in addition to the C-homologue of (±)-β-2-deoxy-glucose 6-phosphate.
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      PubDate: 2015-01-27T11:49:39Z
       
  • Editorial board
    • Abstract: Publication date: 30 January 2015
      Source:Carbohydrate Research, Volume 402




      PubDate: 2015-01-27T11:49:39Z
       
  • Graphical contents list
    • Abstract: Publication date: 30 January 2015
      Source:Carbohydrate Research, Volume 402




      PubDate: 2015-01-27T11:49:39Z
       
  • Recent progress in the field of glycoconjugates
    • Abstract: Publication date: 30 January 2015
      Source:Carbohydrate Research, Volume 402
      Author(s): Carina I.C. Crucho , Paula Correia-da-Silva , Krasimira T. Petrova , M. Teresa Barros
      The ubiquity of glycoconjugates in nature and their role in different biological processes, has led to the development of several methodologies to synthesize these molecules. Synthetic glycoconjugates are now used to answer a variety of glycoconjugate-related biological questions and have provided new potential vaccines against cancer, viral, and bacterial infections and new biotechnological tools. This review aims to collect and compile the recent advances in the field of glycopeptides, glycoproteins, and glycolipid synthesis and also to update the previous reviews made on this subject. Finally, by highlighting the successes and failures of past research, we hope that this review will inspire fruitful research in this important medicinal chemistry field.
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      PubDate: 2015-01-27T11:49:39Z
       
  • Synthesis and characterization of copolyanhydrides of carbohydrate-based
           galactaric acid and adipic acid
    • Abstract: Publication date: 30 January 2015
      Source:Carbohydrate Research, Volume 402
      Author(s): Tuomas Mehtiö , Leena Nurmi , Virpi Rämö , Hannu Mikkonen , Ali Harlin
      A series of copolyanhydrides, consisting of 2,3,4,5-tetra-O-acetylgalactaric acid (AGA) and adipic acid (AA) as monomer units, was polymerized. Synthesis of AGA monomer consisted of two steps. First, O-acetylation of galactaric acid secondary hydroxyl groups was performed using acetic anhydride as a reagent. Acetic anhydride was then further used as a reagent in the synthesis of diacetyl mixed anhydride of AGA. Polymerizations were conducted as bulk condensation polymerization at 150°C. Thermal properties of the copolymers varied depending on monomer composition. Increase in the AGA content had a clear increasing effect on the Tg . A similar increasing effect was observed in Tm . The degree of crystallinity decreased as AGA content increased. There was a slightly lowering tendency in the molecular weights of the obtained polymers when the AGA content in the polymerization mixtures increased. The described synthesis route shows that bio-based aldaric acid monomers are potential candidates for the adjustment of thermal properties of polyanhydrides.
      Graphical abstract image

      PubDate: 2015-01-27T11:49:39Z
       
  • Anomeric selectivity and influenza A virus inhibition study on
           methoxylated analogues of Pentagalloylglucose
    • Abstract: Publication date: 30 January 2015
      Source:Carbohydrate Research, Volume 402
      Author(s): Shaikh Qurat-ul-ain , Wei Wang , Meiting Yang , Na Du , Shengbiao Wan , Lijuan Zhang , Tao Jiang
      Anomeric selectivity in galloylation of d-glucose and d-mannose with carboxylic acid was explored under steglich conditions. Base catalyst 4-dimethylaminopyridine favored the formation of alpha-anomers, while adding an acid and carbodiimide favored the formation of beta-anomers. Steric hindrance between α,β-unsaturated acid and C-2 OH stereochemistry (adjacent carbon to anomeric) influenced anomeric selectivity for both d-glucose and d-mannose. The influenza A virus inhibition activities of the synthesized compounds were evaluated in Madin–Darby canine kidney cell line using the cytopathic effect inhibition assay. All the synthetic methoxylated analogues showed more considerable activity against influenza A virus than their corresponding acids, which indicated the sugar core as key functionality for anti-viral activity. The activities of trimethoxy-cinnamic acid Pentagalloylglucose analogues, 3α, 3β, 4α, and 4β (IC50, 109.1μM, 134.4μM, 119.5μM, 111.1μM, respectively) were better than those of trimethoxy-benzoic acid Pentagalloylglucose analogues, 1-αβ and 2α, 2β (IC50, 209.8μM, 132.9μM, 161.2μM, respectively), which suggested that the double bond in cinnamic acid Pentagalloylglucose analogues makes the major contribution for influenza A virus inhibitory activity. Notably, several anomeric mixtures showed better activities than pure alpha or beta anomer and were almost two times more effective than Ribavirin, a clinically used anti-viral drug.
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      PubDate: 2015-01-27T11:49:39Z
       
  • Halogenated d-xylono-δ-lactams: synthesis and enzyme inhibition study
    • Abstract: Publication date: 30 January 2015
      Source:Carbohydrate Research, Volume 402
      Author(s): Naresh Bhuma , Madhuri Vangala , Roopa J. Nair , Sushma G. Sabharwal , Dilip D. Dhavale
      A concise synthesis of four C-3 fluoro/chloro-d-xylono-δ-lactams 3/4 has been reported. The methodology involves Corey–Link approach with suitably protected 3-oxo-d-gluco-furanose to introduce F/Cl as well as ester/amide functionalities at C-3 of glucose. In next steps, 5,6-O-isopropylidene group was converted to the 5-azido xylosugars that on opening of 1,2-acetonide group, and intramolecular Schmidt–Boyer reaction with TFA/H2O, in one pot, afforded lactams 3/4. Conformational aspect of δ-lactams was studied by the 1H NMR spectroscopy. The halogenated δ-lactams 3/4 showed no inhibition against different glycosidase enzymes.
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      PubDate: 2015-01-27T11:49:39Z
       
  • Synthesis of 4-amidomethyl-1-glucosyl-1,2,3-triazoles and evaluation as
           glycogen phosphorylase inhibitors
    • Abstract: Publication date: 30 January 2015
      Source:Carbohydrate Research, Volume 402
      Author(s): David Goyard , Tibor Docsa , Pál Gergely , Jean-Pierre Praly , Sébastien Vidal
      Glycogen phosphorylase (GP) appears as a key enzyme for the control of hyperglycemia in the context of type 2 diabetes. In order to gain additional data for structure–activity studies of the inhibition of this enzyme, a series of eight GP inhibitor candidates were prepared from peracetylglucopyranosyl azide 1 by click-chemistry. The need for a N-Boc-protected propargylamine was identified in the CuAAC with azide 1 under Meldal’s conditions, while Sharpless’ conditions were better adapted to the CuAAC of azide 1 with propargyl bromide. Cycloaddition of Boc-propargylamine with azide 1 afforded the N-Boc precursor of a 4-aminomethyl-1-glucosyl-1,2,3-triazole which gave access to a series of eight amide and sulfonamide derivatives. After deacetylation, enzymatic studies revealed poor to moderate inhibitions toward this enzyme. The N-Boc-protected amine was the best inhibitor (IC50 =620μM) unexpectedly slightly better than the 2-naphthylamido substituted analogue (IC50 =650μM).
      Graphical abstract image

      PubDate: 2015-01-27T11:49:39Z
       
  • Araf51 with improved transglycosylation activities: one engineered
           biocatalyst for one specific acceptor
    • Abstract: Publication date: 30 January 2015
      Source:Carbohydrate Research, Volume 402
      Author(s): Alizé Pennec , Richard Daniellou , Pascal Loyer , Caroline Nugier-Chauvin , Vincent Ferrières
      A random mutagenesis of the arabinofuranosyl hydrolase Araf51 has been run in order to have access to efficient biocatalysts for the synthesis of alkyl arabinofuranosides. The mutants were selected on their ability to catalyze the transglycosylation reaction of p-nitrophenyl α-l-arabinofuranoside (pNP-Araf) used as a donor and various aliphatic alcohols as acceptors. This screening strategy underlined 5 interesting clones, each one corresponding to one acceptor. They appeared to be much more efficient in the transglycosylation reaction compared to the wild type enzyme whereas no self-condensation or hydrolysis products could be detected. Moreover, the high specificity of the mutants toward the alcohols for which they have been selected validates the screening process. Sequence analysis of the mutated enzymes revealed that, despite their location far from the active site, the mutations affect significantly the kinetics properties as well as the substrate affinity of these mutants toward the alcohol acceptors in the transglycosylation reaction.
      Graphical abstract image

      PubDate: 2015-01-27T11:49:39Z
       
  • Characterization of the N-acetylneuraminic acid synthase (NeuB) from the
           psychrophilic fish pathogen Moritella viscosa
    • Abstract: Publication date: 30 January 2015
      Source:Carbohydrate Research, Volume 402
      Author(s): Tor Olav Berg , Man Kumari Gurung , Bjørn Altermark , Arne O. Smalås , Inger Lin U. Ræder
      Moritella viscosa is a Gram-negative psychrophilic bacterium that causes winter ulcer disease in Atlantic salmon and cod. Its genome reveals that it possesses the ability to synthesize sialic acids. Indeed, sialic acid can be isolated from the bacterium and when analyzed using HPLC-MS/MS, the presence of N-acetylneuraminic acid was confirmed. Thus, the N-acetylneuraminic acid synthase NeuB from M. viscosa (MvNeuB) was recombinantly produced and characterized. The optimum pH and temperature for MvNeuB activity are 7.5 and 30°C, respectively. The K M for N-acetylmannosamine and phosphoenolpyruvate is 18±5 and 0.8±0.2mM, respectively. The k cat value (∼225min−1) for both N-acetylmannosamine and phosphoenolpyruvate is the highest turnover number found for an enzyme in this class until the date. A calorimetric study of MvNeuB shows that the enzyme has a two-step transition peak probably reflecting the two domains these proteins consist of. MvNeuB is less stable at higher temperature and has a high catalytic activity at lower temperature compared to mesophilic counterparts. Enzymes from psychrophilic organisms are generally cold adapted meaning they can maintain adequate function near the freezing point of water. Cold adapted enzymes are catalytically more efficient at lower temperature and are more thermo-labile compared to their mesophilic counterparts. MvNeuB is a typical cold adapted enzyme and could be further explored for production of sialic acids and derivates at low temperatures.
      Graphical abstract image

      PubDate: 2015-01-27T11:49:39Z
       
  • Selective glycosylation of steroidal saponins by Arthrobacter
           nitroguajacolicus
    • Abstract: Publication date: 30 January 2015
      Source:Carbohydrate Research, Volume 402
      Author(s): Jing-yuan Liu , Li Lu , Li-ping Kang , Yi-xun Liu , Yang Zhao , Cheng-qi Xiong , Yu-qin Zhang , Li-yan Yu , Bai-ping Ma
      In this study seven strains of the genus Arthrobacter were screened by biotransformation to discover glycosylating patterns on steroid saponins. A strain of Arthrobacter nitroguajacolicus (CPCC 203516) was found to have the ability of fructosylation. Crude enzyme of the strain was extracted for the further study of conversion characteristics and patterns. Sucrose was used as a non-activated sugar donor, and fifteen steroidal saponins were involved. Nine furostan saponins of the substrates were converted, and ten products were isolated and identified. Based on the HR-ESI-MS, 1D, and 2D NMR spectral data, one fructosyl was added to furostan saponins at C6-OH of 26-O-β-d-glucopyranosyl by A. nitroguajacolicus for all nine products. One product was distinguished by an additional fructosyl at the position of C6-OH on the first added fructosyl. Spirostan saponins of the substrates could not be converted. Steroidal saponins embracing a fructosyl are quite rare according to other reports based on similar studies. This study successfully converted furostan saponins into new compounds.
      Graphical abstract image

      PubDate: 2015-01-27T11:49:39Z
       
  • Structural identification of 4-benzyl-voglibose hydrochloride monohydrate
           using NMR and single-crystal X-ray diffraction methods
    • Abstract: Publication date: 30 January 2015
      Source:Carbohydrate Research, Volume 402
      Author(s): Fen-Fen Zhang , Yu-Qin Zhao , Jian-Ping Fan , Li-Gang Liu , Rui-Wen Li , Wen-Bin Shen , Ya Ding
      The chemical structure studies on an important related substance of voglibose have been carried out using NMR spectroscopy and single crystal X-ray crystallography. For the structure identification study, hydrochloride monohydrate of this compound was isolated and purified. Its molecular structure was characterized and analyzed using 1D (1H NMR, 13C NMR, and DEPT) and 2D (1H,1H-COSY, HSQC, HMBC, TOCSY, and ROESY) NMR spectra. The signal crystal structure was detected by X-ray crystallography. All results indicated this related substance of voglibose was C17H27NO7·HCl·H2O, 5,6-dideoxy-4-benzyl-5-{[2-hydroxy-1-(hydroxymethyl)ethy]amino}-1-C-(hydroxymethyl)-d-epi-inositol hydrochloride monohydrate.
      Graphical abstract image

      PubDate: 2015-01-27T11:49:39Z
       
  • Elucidation of differences in N-glycosylation between different molecular
           weight forms of recombinant CLEC-2 by LC MALDI tandem MS
    • Abstract: Publication date: 30 January 2015
      Source:Carbohydrate Research, Volume 402
      Author(s): Lei Zhou , Yifan Qian , Xingwang Zhang , Yuanyuan Ruan , Shifang Ren , Jianxin Gu
      C-type lectin-like receptor 2 (CLEC-2) is a newly identified receptor expressed on the platelet surface. It has been reported that CLEC-2 exists as a higher molecular weight (HMW) and a lower molecular weight (LMW) form, which share the same protein core but differ in glycans. The two forms appear to have different ligand-binding abilities, indicating that the differential glycosylation of CLEC-2 possibly produces functionally distinct glycoforms. This study aimed to explore an easy method to directly elucidate the N-glycosylation difference by employing a glycoproteomics approach. The off-line coupling of nano-LC with a MALDI-QIT-TOF mass spectrometer was demonstrated to be capable of sensitive and direct elucidation of the glycosylation difference between HMW and LMW CLEC-2, simultaneously providing information about their oligosaccharide structures and the glycosylation sites. The results reveal that a specific glycosylation site, Asn 134, is differently glycosylated in the two forms, with complex types of bi-antennary, tri-antennary and tetra-antennary, N-linked, fucosylated glycans identified at this site in the HMW form but not in the LMW form. The observed difference in glycosylation might provide new insights into the underlying mechanisms of biological functions of CLEC-2. Because of its simplicity and sensitivity, the method explored in this work suggests that it holds promise as a method of elucidating differences in direct N-glycosylation of target glycoprotein, even in small amount of samples.
      Graphical abstract image

      PubDate: 2015-01-27T11:49:39Z
       
  • Triterpenoid saponins from root bark of Zanha golungensis (Sapindaceae)
    • Abstract: Publication date: 30 January 2015
      Source:Carbohydrate Research, Volume 402
      Author(s): Catherine Lavaud , Charlotte Sayagh , Franck Humbert , Isabelle Pouny , Clément Delaude
      The chemical investigation of the methanolic extract from root bark of Zanha golungensis Hiern led to the isolation of five new and one known triterpenoid saponins. Their structures were elucidated by full analysis of their spectroscopic data and by partial hydrolysis. These glycosides contain zanhic acid as aglycone, a rare oleanane-type triterpenoid found in species belonging to Sapindaceae, Caryophyllaceae, Asteraceae, and Fabaceae. Two new saponins are esterified saponins by 3,3-dimethylacryloyl and 3-hydroxy-2-methyl-butanoyl residues located on the sugar part. The new compounds were named zanhasaponins D–H following previous isolation of similar compounds from Zanha africana.
      Graphical abstract image

      PubDate: 2015-01-27T11:49:39Z
       
  • Steroidal saponins obtained by biotransformation of total furostanol
           glycosides from Dioscorea zingiberensis with Absidia coerulea
    • Abstract: Publication date: 30 January 2015
      Source:Carbohydrate Research, Volume 402
      Author(s): Xu Pang , Di Wen , Yang Zhao , Cheng-Qi Xiong , Xiao-Qin Wang , Li-Yan Yu , Bai-Ping Ma
      Five new steroidal saponins (1–5) were isolated from the fermentation broth of total furostanol glycosides from tubers of Dioscorea zingiberensis C.H. Wright incubated with a fungal, Absidia coerulea AS 3.3389, along with known saponins, zingiberensis new saponin (6), deltonin (7), prosapogenin A of dioscin (8), and protobioside (9), and their structures were established by NMR spectroscopy and mass spectrometry as well as by comparison with previously reported spectral data in the literatures. The induced effects in vitro on rat platelet aggregation of all compounds were evaluated.
      Graphical abstract image

      PubDate: 2015-01-27T11:49:39Z
       
  • Structural characterization and gastroprotective property of a novel
           glucofructan from Allium ampeloprasum var. porrum
    • Abstract: Publication date: 30 January 2015
      Source:Carbohydrate Research, Volume 402
      Author(s): Camila R.A. Malafaia , Bernadete P. da Silva , Luzineide W. Tinoco , José P. Parente
      A new polysaccharide with an estimated weight-average molar mass of 2.6×103 was isolated from Allium ampeloprasum var. porrum by hot water extraction, and purified by Sephacryl S-300 HR high-resolution chromatography. It was composed of d-fructose and d-glucose in 10:6 molar ratio, respectively. The structure of the glucofructan was investigated by chemical and spectroscopic methods, including methylation analysis, nuclear magnetic resonance, and electrospray mass spectrometry (ES-MS). The results permitted the structure of the glucofructan to be written as α-d-Glcp-(1→1)-β-d-Fruf-(2→1)-{[α-d-Glcp-(1→6)-β-d-Fruf-(2→6)]-β-d-Fruf-(2→1)}4-β-d-Fruf-(2↔1)-α-d-Glcp. Results of the present study indicated that this new glucofructan exhibited significant gastroprotective property, using in vivo experimental models.
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      PubDate: 2015-01-27T11:49:39Z
       
  • Generation and structural validation of a library of diverse
           xyloglucan-derived oligosaccharides, including an update on xyloglucan
           nomenclature
    • Abstract: Publication date: 30 January 2015
      Source:Carbohydrate Research, Volume 402
      Author(s): Sami T. Tuomivaara , Katsuro Yaoi , Malcolm A. O’Neill , William S. York
      Xyloglucans are structurally complex plant cell wall polysaccharides that are involved in cell growth and expansion, energy metabolism, and signaling. Determining the structure–function relationships of xyloglucans would benefit from the availability of a comprehensive and structurally diverse collection of rigorously characterized xyloglucan oligosaccharides. Here, we present a workflow for the semi-preparative scale generation and purification of neutral and acidic xyloglucan oligosaccharides using a combination of enzymatic and chemical treatments and size-exclusion chromatography. Twenty-six of these oligosaccharides were purified to near homogeneity and their structures validated using a combination of matrix-assisted laser desorption/ionization mass spectrometry, high-performance anion exchange chromatography, and 1H nuclear magnetic resonance spectroscopy. Mass spectrometry and analytical chromatography were compared as methods for xyloglucan oligosaccharide quantification. 1H chemical shifts were assigned using two-dimensional correlation spectroscopy. A comprehensive update of the nomenclature describing xyloglucan side-chain structures is provided for reference.
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      PubDate: 2015-01-27T11:49:39Z
       
  • Structural studies of the exopolysaccharide from Lactobacillus plantarum
           C88 using NMR spectroscopy and the program CASPER
    • Abstract: Publication date: 30 January 2015
      Source:Carbohydrate Research, Volume 402
      Author(s): Carolina Fontana , Shengyu Li , Zhennai Yang , Göran Widmalm
      Some lactic acid bacteria, such as those of the Lactobacillus genus, have the ability to produce exopolysaccharides (EPSs) that confer favorable physicochemical properties to food and/or beneficial physiological effects on human health. In particular, the EPS of Lactobacillus plantarum C88 has recently demonstrated in vitro antioxidant activity and, herein, its structure has been investigated using NMR spectroscopy and the computer program CASPER (Computer Assisted Spectrum Evaluation of Regular polysaccharides). The pentasaccharide repeating unit of the O-deacetylated EPS consists of a trisaccharide backbone, →4)-α-d-Galp-(1→2)-α-d-Glcp-(1→3)-β-d-Glcp-(1→, with terminal d-Glc and d-Gal residues (1.0 and 0.8equiv per repeating unit, respectively) extending from O3 and O6, respectively, of the →4)-α-d-Galp-(1→ residue. In the native EPS an O-acetyl group is present, 0.85equiv per repeating unit, at O2 of the α-linked galactose residue; thus the repeating unit of the EPS has the following structure: →4)[β-d-Glcp-(1→3)][β-d-Galp-(1→6)]α-d-Galp2Ac-(1→2)-α-d-Glcp-(1→3)-β-d-Glcp-(1→. These structural features, and the chain length (∼103 repeating units on average, determined in a previous study), are expected to play an important role in defining the physicochemical properties of the polymer.
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      PubDate: 2015-01-27T11:49:39Z
       
  • Structural investigation of a uronic acid-containing polysaccharide from
           abalone by graded acid hydrolysis followed by PMP-HPLC–MSn and NMR
           analysis
    • Abstract: Publication date: 30 January 2015
      Source:Carbohydrate Research, Volume 402
      Author(s): Hong-xu Wang , Jun Zhao , Dong-mei Li , Shuang Song , Liang Song , Ying-huan Fu , Li-peng Zhang
      A new strategy was applied to elucidate the structure of a polysaccharide from abalone gonad (AGSP). It was hydrolyzed by 0.05M, 0.2M, 0.5M, and 2.0M TFA at 100°C for 1h, sequentially. Every hydrolysate was ultrafiltrated (3000Da) to collect oligo- and monosaccharides, and the final retentate was further hydrolyzed with 2.0M TFA at 110°C and 121°C for 2h, respectively. 1-Phenyl-3-methyl-5-pyrazolone (PMP) derivatization followed by HPLC–MSn analysis was applied to detect the sugar residues in these hydrolysates, which allowed proposing their location in the polysaccharide structure. The retentate after 0.5M TFA hydrolysis was confirmed as the polysaccharide backbone, and it was further analyzed by 1D and 2D NMR spectroscopy. Thus, the structural elucidation of AGSP was accomplished, and it has a backbone of →4)-β-GlcA(1→2)-α-Man(1→ repeating unit with Fuc, Xyl and Gal in the branch. The analytical strategy demonstrated was useful to characterize the structure of polysaccharides.
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      PubDate: 2015-01-27T11:49:39Z
       
  • The core and O-polysaccharide structure of the Caulobacter crescentus
           lipopolysaccharide
    • Abstract: Publication date: 30 January 2015
      Source:Carbohydrate Research, Volume 402
      Author(s): Michael D. Jones , Evgeny Vinogradov , John F. Nomellini , John Smit
      Here we describe the analysis of the structure of the lipopolysaccharide (LPS) from Caulobacter crescentus strain JS1025, a derivative of C. crescentus CB15 NA1000 with an engineered amber mutation in rsaA, leading to the loss of the protein S-layer and gene CCNA_00471 encoding a putative GDP-l-fucose synthase. LPS was isolated using an aqueous membrane disruption method. Polysaccharide and core oligosaccharide were produced by mild acid hydrolysis and analyzed by nuclear magnetic resonance spectroscopy and chemical methods. Spectra revealed the presence of two polysaccharides, one of them, a rhamnan, could be removed using periodate oxidation. Another polymer, built from 4-amino-4-deoxy-d-rhamnose (perosamine), mannose, and 3-O-methyl-glucose, should be the O-chain of the LPS according to genetic data. The attribution of the rhamnan as a part of LPS or a separate polymer was not possible.
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      PubDate: 2015-01-27T11:49:39Z
       
  • Relative reactivities in the O-methylation of glucomannans: the influence
           of stereochemistry at C-2 and the solvent effect
    • Abstract: Publication date: 30 January 2015
      Source:Carbohydrate Research, Volume 402
      Author(s): Yujia Zhang , Jiebing Li , Mikael E. Lindström , Petra Mischnick
      The main hemicellulose in softwood, glucomannan (GM), structurally resembles cellulose but has quite different physical and chemical properties. In addition to branching and original acetylation, the only other difference between these two β-1,4-linked glycans is the configuration at C-2 in approximately 80% of the sugar residues. In contrast to glucose, the 2-OH in mannose has an axial orientation. The influence of this stereochemistry on the relative reactivities of glucosyl compared to mannosyl units in methylation reactions are studied in this work. Glucomannan isolated from spruce (SGM) and commercially available konjac glucomannan (KGM) was methylated in DMSO/Li-dimsyl/MeI and water/NaOH/MeI system, respectively. In the early stage of the reaction, the glucose part of the SGM achieved slightly higher DS values than the mannose residues, but the overall relative rate constants were close to 1:1. The order of reactivities in glucose was k 2 > k 3 > k 6 and k 3 > k 2 > k 6 for mannose (in DMSO/Li-dimsyl/MeI). The rate constants did not remain constant, but k 3 decreased when k 2 increased for both epimeric sugars. In water/NaOH/MeI, the methylation of the primary 6-OH was much more pronounced with an order of reactivity of O-6>O-2>O-3 for mannose and O-2>O-6>O-3 for glucose. The results are discussed with respect to the OH-acidity and the stereoelectronic, sterical, and solvent effects.
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      PubDate: 2015-01-27T11:49:39Z
       
  • Analysis of breast cancer-associated glycosphingolipids using electrospray
           ionization-linear ion trap quadrupole mass spectrometry
    • Abstract: Publication date: 30 January 2015
      Source:Carbohydrate Research, Volume 402
      Author(s): Tingting Zhu , Longjiang Xu , Xiukun Xu , Zheng Wang , Jian Zhu , Qing Xie , Biyan Zhang , Yanping Wang , Linling Ju , Yun He , Xinshan Ye , Dapeng Zhou , Yunsen Li
      Abnormal glycosphingolipids (GSLs) are expressed in many human tumors. These tumor-associated GSLs may have important roles in tumor progression. However, they are hard to be detected because of their low concentration and the limited availability of antibodies and lectins that recognize them. Thus, mass spectrometry is an effective method to analyze GSLs with high sensitivity. Here, we use electrospray ionization-linear ion trap quadrupole mass spectrometry (ESI-LTQ-MS) and liquid chromatography/electrospray ionization tandem mass spectrometry (LC/ESI-MS/MS) to determine the structure of a certain GSL in human breast cancer tissue. To obtain the breast cancer-associated GSLs, we applied relative abundance contrast of GSLs and signal-to-noise ratio (SNR) analyses. We also used α1,2 fucosidase and fucosyltransferases as tools in the structural analysis. Based on this analysis, we identified the ion with m/z 1184 molecular ion as fucosyl-lactoceramide (Fuc-LacCer) with a C16 fatty acid ceramide. Quantitative analysis of GSLs revealed both Fuc-LacCer and Globo-H increased in breast cancer tissues. However, these two breast cancer-associated GSLs had different roles. The results of SNR analysis suggested the abnormal Fuc-LacCer is specific to breast cancer. The GSL profiling of breast cancer cells showed fucosyltransferase 1 contributed to the biosynthesis of Globo-H and Fuc-LacCer. In conclusion, MS analysis identified an accumulation of Fuc-LacCer in breast cancer tissue. Our findings provide GSL profiles of human breast cancer and develop an MS method for the study of cancer-associated GSLs.
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      PubDate: 2015-01-27T11:49:39Z
       
  • A supramolecular vesicle of camptothecin for its water dispersion and
           controllable releasing
    • Abstract: Publication date: 30 January 2015
      Source:Carbohydrate Research, Volume 402
      Author(s): Mingfang Ma , Wenqing Shang , Pengyao Xing , Shangyang Li , Xiaoxiao Chu , Aiyou Hao , Guangcun Liu , Yimeng Zhang
      Camptothecin, as an antitumor drug, has shown significant antitumor activity against various cancers through the inhibition of topoisomerase I. However, its poor solubility severely limits the clinical applications. Here, we report a camptothecin supramolecular vesicle based on the host–guest interactions, which can uniformly disperse camptothecin into water and greatly enhance camptothecin aqueous solubility. The camptothecin vesicles were identified by transmission electron microscopy (TEM), scanning electron microscopy (SEM), and dynamic light scattering (DLS). X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), UV–vis spectrum, 1H NMR and 2D NMR ROESY were further employed to study the formation mechanism of the vesicles. Furthermore, camptothecin could be controllably released when the competitive guests were added into the vesicles system. Finally, the camptothecin vesicles in aqueous solution exhibited comparable antitumor activity in vitro as natural camptothecin in DMSO to HeLa cells under the same conditions.
      Graphical abstract image Highlights

      PubDate: 2015-01-27T11:49:39Z
       
  • The structure of the Morganella morganii lipopolysaccharide core region
           and identification of its genomic loci
    • Abstract: Publication date: 30 January 2015
      Source:Carbohydrate Research, Volume 402
      Author(s): Evgeny Vinogradov , John H.E. Nash , Simon Foote , N. Martin Young
      The core region of the lipopolysaccharide of Morganella morganii serotype O:1ab was obtained by hydrolysis of the LPS and studied by 2D NMR, ESI MS, and chemical methods. Its structure was highly homologous to those from the two major members of the same Proteeae tribe, Proteus mirabilis and Providencia alcalifaciens, and analysis of the M. morganii genome disclosed that the loci for its outer core, lipid A and Ara4N moieties are similarly conserved.
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      PubDate: 2015-01-27T11:49:39Z
       
  • Shielding effect of ‘surface ion pairs’ on physicochemical and
           bactericidal properties of N,N,N-trimethyl chitosan salts
    • Abstract: Publication date: 30 January 2015
      Source:Carbohydrate Research, Volume 402
      Author(s): Alessandro F. Martins , Suelen P. Facchi , Heveline D.M. Follmann , Adriana P. Gerola , Adley F. Rubira , Edvani C. Muniz
      Different methodologies were employed in this study to synthesize N,N,N-trimethyl chitosan salts (TMC). TMC free of O-methylation and with partial O-methylation were obtained and characterized through 1H nuclear magnetic resonance, wide angle X-ray scattering, scanning electron microscopy coupled with X-ray energy dispersive spectroscopy, and thermogravimetric analysis. It was verified that the dialysis process allowed the removal of ‘surface ion pairs’ on TMC salt structure, increasing the mobility of TMC chains. The surface ion pairs considerably increased the material crystallinity, this property being independent of the used synthesis methodology. Biological tests showed that after dialysis, TMC salts free of ‘surface ion pairs’ kill Escherichia coli in only 6h of incubation. So, the increase in the mobility of dialyzed TMC chains allowed a strong interaction with the cell envelope and the good bactericidal activity of TMC was enhanced.
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      PubDate: 2015-01-27T11:49:39Z
       
  • Computational study to evaluate the birefringence of uniaxially oriented
           film of cellulose triacetate
    • Abstract: Publication date: 30 January 2015
      Source:Carbohydrate Research, Volume 402
      Author(s): Daichi Hayakawa , Kazuyoshi Ueda
      The intrinsic birefringence of a cellulose triacetate (CTA) film is evaluated using the polarizability of the monomer model of the CTA repeating unit, which is calculated using the density functional theory (DFT). Since the CTA monomer is known to have three rotational isomers, referred to as gg, gt, and tg, the intrinsic birefringence of these isomers is evaluated separately. The calculation indicates that the monomer CTA with gg and gt structures shows a negative intrinsic birefringence, whereas the monomer unit with a tg structure shows a positive intrinsic birefringence. By using these values, a model of the uniaxially elongated CTA film is constructed with a molecular dynamics simulation, and the orientation birefringence of the film model was evaluated. The result indicates that the film has negative orientation birefringence and that its value is in good agreement with experimental results.
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      PubDate: 2015-01-27T11:49:39Z
       
  • Montmorillonite K-10 promoted synthesis of chiral dioxa-caged compounds
           derived from levoglucosenone
    • Abstract: Publication date: 30 January 2015
      Source:Carbohydrate Research, Volume 402
      Author(s): Mariano A. Zurita , Aylén Avila , Rolando A. Spanevello , Alejandra G. Suárez , Ariel M. Sarotti
      A short and efficient methodology for the synthesis of chiral dioxa-caged compounds from levoglucosenone, a biomass-derived enone, is herein presented. The key transformation, that involves a cascade 3-step cationic cyclization, was efficiently carried out in high yields and selectivities by Montmorillonite K-10 catalysis. The usefulness of K-10 in related semi-pinacol rearrangements to obtain pyran-3-ones is also shown. Interesting differences in the reactivity pattern was found for epimeric alcohols, and the origins of these findings were determined by DFT calculations.
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      PubDate: 2015-01-27T11:49:39Z
       
  • One-pot SSA-catalyzed β-elimination: an efficient and inexpensive
           protocol for easy access to the glycal of sialic acid
    • Abstract: Publication date: 30 January 2015
      Source:Carbohydrate Research, Volume 402
      Author(s): Erickson M. Paragas , I. Abrrey Monreal , Chris M. Vasil , Jonel P. Saludes
      Neu5Ac2en1Me per-OAc, the fully protected glycal of sialic acid, is a key intermediate in the discovery of therapeutics and diagnostics, including anti-influenza drugs and proteolysis resistant peptidomimetic foldamers. The synthesis of this sialic acid derivative, however, still relies on standard sugar chemistry that utilizes multi-step methodologies. Herein we report a facile and highly efficient microwave-assisted preparation of Neu5Ac1Me using silica sulfuric acid (SSA) as solid-supported acid catalyst that is one- to two-orders of magnitude faster than standard procedures. We also describe the microwave-assisted and SSA-catalyzed one-pot, rapid, solvent free reaction that combines both peracetylation and β-elimination reactions in one step to generate the glycal from Neu5Ac1Me. We coined the term One-pot SSA-catalyzed Technology for β-Elimination Protocol (OneSTEP) to describe this least laborious, most efficient, and practical preparation to date of Neu5Ac2en1Me per-OAc in terms of yield, time, reagent cost, and waste generation.
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      PubDate: 2015-01-27T11:49:39Z
       
  • Direct thiophenylation accompanying orthoester-cleavage of
           1,2,4-O-orthoacetyl-3,6-O-(o-xylylene)glucopyranose
    • Abstract: Publication date: 30 January 2015
      Source:Carbohydrate Research, Volume 402
      Author(s): Takuya Uchino , Yusuke Tomabechi , Atsushi Fukumoto , Hidetoshi Yamada
      The 3,6-O-(o-xylylene) bridge locks the conformation of glucopyranose to an axial-rich form. Although the conformational lock induces complete β-selectivity in a glycosylation reaction, the leaving group of the glycosyl donor is limited to fluorine. On the other hand, the bridge confers the furanose-preferred property to glucose, which makes synthesis of corresponding pyranosyl derivatives that equip various leaving groups difficult. This problem was solved through direct phenylthio glucosidation of 3,6-O-(o-xylylene)-1,2,4-O-orthoacetylglucose accompanying cleavage of the orthoester moiety. This paper describes the process of establishing direct thiophenylation. This process reduced the synthetic steps for the known glucopyranosyl fluoride and will expand application of conformationally locked glycosyl donors.
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      PubDate: 2015-01-27T11:49:39Z
       
  • Synthesis of mixed glycosyl disulfides/selenenylsulfides using
           benzyltriethylammonium tetrathiomolybdate as a sulfur transfer reagent
    • Abstract: Publication date: 30 January 2015
      Source:Carbohydrate Research, Volume 402
      Author(s): Cheerladinne Venkateswarlu , Vibha Gautam , Srinivasan Chandrasekaran
      An easy and mild method has been developed for the synthesis of mixed glycosyl disulfides/selenenylsulfides from glycosyl halides and diaryl/dialkyl dichalcogenides in the presence of benzyltriethylammonium tetrathiomolybdate [(BnEt3N)2MoS4]. The salient feature of this method is the sulfur transfer from [BnEt3N]2MoS4 to form glycosyl disulfides which with excess tetrathiomolybdate further undergo exchange reaction with other dichalcogenides in a one-pot operation.
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      PubDate: 2015-01-27T11:49:39Z
       
  • Stabilization of ribofuranose by a mineral surface
    • Abstract: Publication date: 30 January 2015
      Source:Carbohydrate Research, Volume 402
      Author(s): Thomas Georgelin , Maguy Jaber , Frédéric Fournier , Guillaume Laurent , France Costa-Torro , Marie-Christine Maurel , Jean-Francois Lambert
      The existence of the ribose moiety in biomolecules poses two problems for prebiotic chemistry. First, the exclusive presence of the furanose isomer in RNA has to be accounted for since furanose is a minor form in solution and does not exist in crystals. Second, all d-ribose polymorphs are unstable in aqueous medium so that a stabilization mechanism has to be invoked. We observed that the adsorption on mineral surfaces as amorphous silica protects the sugar from degradation processes. Moreover, this silica surface, used as realistic chert model, is able to increase significantly the proportion of ribofuranose compared to ribopyranose forms. The interaction between surface and sugar was analyzed by 13C NMR. Our results show a very significant chemical and thermal stabilization of the adsorbed sugar by a silica surface and an almost twofold increase of ribofuranose compared to ribose in solution.
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      PubDate: 2015-01-27T11:49:39Z
       
  • Structure of the O-specific polysaccharide from a marine bacterium
           Echinicola vietnamensis KММ 6221Т
    • Abstract: Publication date: 30 January 2015
      Source:Carbohydrate Research, Volume 402
      Author(s): Svetlana V. Tomshich , Maxim S. Kokoulin , Anatoliy I. Kalinovsky , Nadezhda A. Komandrova , Ol’ga I. Nedashkovskaya
      The O-specific polysaccharide was isolated from the lipopolysaccharide of Echinicola vietnamensis and studied by chemical methods along with 1H and 13C NMR spectroscopy, including 2D 1H, 1H COSY, TOCSY, ROESY, 1H, 13C HSQC, HMBC, and H2BC experiments. It was found that the polysaccharide is built up of branched tetrasaccharide repeating units, containing 2-acetamido-2-deoxy-d-glucuronic acid (GlcNAcA), 2-acetamido-2-deoxy-d-galactose (GalNAc), and d-glucuronic acid (GlcA) with a terminal residue of 3,6-dideoxy-l-xylo-hexose (colitose, Col) and has the following structure.
      Graphical abstract image

      PubDate: 2015-01-27T11:49:39Z
       
  • Triterpenoid saponins from Albizia lebbeck (L.) Benth and their inhibitory
           effect on the survival of high grade human brain tumor cells
    • Abstract: Publication date: Available online 23 January 2015
      Source:Carbohydrate Research
      Author(s): Olivier Placide Noté , Dong Jihu , Cyril Antheaume , Maria Zeniou , Dieudonné Emmanuel Pegnyemb , Dominique Guillaume , Hervé Chneiwess , Marie Claude Kilhoffer , Annelise Lobstein
      As part of our search of new bioactive triterpenoid saponins from Cameroonian Mimosaceae plants, phytochemical investigation of the roots of Albizia lebbeck led to the isolation of two new oleanane-type saponins, named lebbeckosides A–B (1–2). Their structures were established on the basis of extensive 1D and 2D NMR (1H-, 13C-NMR, DEPT, COSY, TOCSY, ROESY, HSQC and HMBC) and HRESIMS studies, and by chemical evidence. Compounds 1–2 were evaluated for their inhibitory effect on the metabolism of high grade human brain tumor cells, the human glioblastoma U-87 MG cell lines and the glioblastoma stem-like TG1 cells isolated from a patient tumor, and known to be particularly resistant to standard therapies. The isolated saponins showed significant cytotoxic activity against U-87 MG and TG1 cancer cells with IC50 values of 3.46 μM and 1.36 μM for 1, and 2.10 μM and 2.24 μM for 2, respectively.
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      PubDate: 2015-01-27T11:49:39Z
       
  • ‛Click chemistry‛ synthesis of
           1-(α-D-mannopyranosyl)-1,2,3-triazoles for inhibition of
           α-mannosidases.
    • Abstract: Publication date: Available online 19 January 2015
      Source:Carbohydrate Research
      Author(s): Monika Poláková , Rhiannon Stanton , Iain B.H. Wilson , Ivana Holková , Sergej Šesták , Eva Machová , Zuzana Jandová , Juraj Kóňa
      Three new triazole conjugates derived from D-mannose were synthesized and assayed in in vitro assays to investigate their ability to inhibit α-mannosidase enzymes from the glycoside hydrolase (GH) families 38 and 47. The triazole conjugates were more selective for a GH47 α-mannosidase (Aspergillus saitoi α1,2-mannosidase), showing inhibition at the micromolar level (IC50 values of 50-250 μM), and less potent towards GH38 mannosidases (IC50 values in the range of 0.5-6 mM towards jack bean α-mannosidase or Drosophila melanogaster lysosomal and Golgi α-mannosidases). The highest selectivity ratio [IC50(GH38)/IC50(GH47)] of 100 was exhibited by the phenyltriazole conjugate. To understand structure-activity properties of synthesized compounds, 3-D complexes of inhibitors with α-mannosidases were built using molecular docking calculations.
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      PubDate: 2015-01-27T11:49:39Z
       
  • Functional glycolipid-crown-ethers by click chemistry
    • Abstract: Publication date: Available online 19 January 2015
      Source:Carbohydrate Research
      Author(s): Abbas Abdulameer Salman , Mojtaba Tabandeh , Thorsten Heidelberg , Rusnah Syahila Duali Hussen
      A series of glycolipid crown ether analogs was prepared by bis-propargylation of lauryl glycoside followed by subsequent click-coupling with ethylene glycol-based diazides. The triazole-linked macrocycles were obtained in remarkable high yields. While the surfactant assembly was affected by presence of sodium ions, suggesting the formation of complexes, no ion-selectivity was observed for the macrocylic ligands. Computational studies suggest a low but significant cation-binding activity of the macrocycle, involving coordination at both oxygen and nitrogen atoms.
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      PubDate: 2015-01-27T11:49:39Z
       
  • Quantitative Characterization of Hydration State and Destructuring Effect
           of Monosaccharides and Disaccharides on Water Hydrogen Bond Network
    • Abstract: Publication date: Available online 15 January 2015
      Source:Carbohydrate Research
      Author(s): K. Shiraga , T. Suzuki , N. Kondo , J. De Baerdemaeker , Y. Ogawa
      Terahertz time-domain attenuated total reflection measurements of monosaccharide (glucose and fructose) and disaccharide (sucrose and trehalose) solutions from 0.146 M to 1.462 M were performed to evaluate (1) the hydration state and (2) the destructuring effect of saccharide solutes on the hydrogen bond (HB) network. Firstly, the extent of hydration water was determined by the decreased amount of bulk water with picosecond relaxation time that was replaced by that with much longer orientational relaxation time. As a result, we found glucose and trehalose exhibits stronger hydration capacity than fructose and sucrose, respectively, despite of the same number of the hydroxyl groups. For each saccharide, the hydration number tended to decrease with solute concentration. Secondly, the destructuring effect of these saccharide solutes on the HB network of the surrounding bulk water was discussed from the perspective of the fraction of non-hydrogen-bonded (NHB) water isolated from the HB network. We found the fraction of NHB water molecules that are not engaged in the HB network monotonously increased with saccharide concentration, indicating saccharide solutes promote the disruption of the water HB network. However, no noticeable differences were confirmed in the fraction of NHB water between glucose and fructose or between sucrose and trehalose. In contrast to hydration number, the number of NHB water produced by a single saccharide solute was less dependent on solute concentration, and three monosaccharide/disaccharide solutes were found to produce one/two NHB water molecules.
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      PubDate: 2015-01-27T11:49:39Z
       
  • Structural Features of a Novel Polysaccharide Isolated from a New Zealand
           Maori Mushroom Iliodiction cibarium
    • Abstract: Publication date: Available online 14 January 2015
      Source:Carbohydrate Research
      Author(s): Lu Ren , Patrick J.B. Edwards , Conrad O. Perera , Yacine Hemar
      A purified water-soluble fraction (ICP5) of a polysaccharide, isolated from a local Maori mushroom Iliodiction cibarium in New Zealand, was investigated for its structural properties. Size exclusion chromatography and dynamic light scattering showed that ICP5 had a large MW of 1.6 × 105 Da with a hydrodynamic diameter of 83 ± 8 nm. Particle size measurements also displayed the tendency of ICP5 to aggregate when suspended in water. The results of GC-MS, FT-IR and NMR analyses allowed some characteristics of the chemical structure of ICP5 to be determined. GC-MS results showed that ICP5 contained only glucose (81.61%), galactose (12.90%) and mannose (5.49%) monomers. The characterized fragment structures of ICP5 were found to be dominantly consisting of uronic acids, which formed a backbone containing 1, 4-β-D-GlcpA. A small amount of unsaturated uronic acid also appeared to be present.
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      PubDate: 2015-01-27T11:49:39Z
       
  • Synthetic study of 3-fluorinated sialic acid derivatives
    • Abstract: Publication date: Available online 13 January 2015
      Source:Carbohydrate Research
      Author(s): Katsuhiko Suzuki , Shusaku Daikoku , Sang-Hyun Son , Yukishige Ito , Osamu Kanie
      Sialic acid derivatives, analogs, and their conjugates are expected to be pharmaceutical candidates such as anti-influenza drugs and also useful probes for investigating the biological role of glycoconjugates. Derivatives of 3-fluorinated sialic acid (3-F-Sia) have been found to be excellent probes in investigating functions and mechanisms of a series of proteins. Here, we describe the syntheses of 3-F-Sia derivatives, which are useful in making biologically important conjugate probes. A practical method for the construction of 3-fluorinated sialosides based on the stereoselective formation of the corresponding anomeric O-trimethylsilyl ether and their nucleophilic attack by an alkyl halide, an allyl halide in particular, was developed. In addition, details of the synthesis of cytidine monophosphate (CMP)-3-F-Sia bearing a fluorescent tag, which has been proven to show dual functions as a substrate of CMP-sialic acid transporter (CST) and an inhibitor of sialyltransferase (STase), are described.
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      PubDate: 2015-01-27T11:49:39Z
       
  • Characteristics of Mannosylerythritol Lipids and their Enviornmental
           Potential1
    • Abstract: Publication date: Available online 13 January 2015
      Source:Carbohydrate Research
      Author(s): Mingda Yu , Zhifeng Liu , Guangming Zeng , Hua Zhong , Yang Liu , Yongbing Jiang , Min Li , Xiaoxiao He , Yan He
      Mannosylerythritol lipids (MELs) are promissing biosurfactants containing two glycosyl derivatives and various fatty acids, which are mainly secreted by Pseudozyma as well as Ustilago. In this review, the latest research is demonstrated on production conditions, structural diversity, self-assembling properties and versatile biochemical functions of MELs. The genetic study and synthetic pathways which mainly influence the type and yield of MELs production. Due to the excellent surface activity, biocompatibility and restorative function, MELs can be used in enviornmental industry which has not been widely noted. In this paper, the current status of research on enviornmental potential of MELs has been disscussed including petroleum degradation, bioconversion of chemical wastes and enhanced bioremediation of amphiphilic wastes.
      Graphical abstract image

      PubDate: 2015-01-27T11:49:39Z
       
  • Capsular polysaccharide conformations in pneumococcal serotypes 19F and
           19A
    • Abstract: Publication date: Available online 13 January 2015
      Source:Carbohydrate Research
      Author(s): Michelle Kuttel , Graham E. Jackson , Mpho Mafata , Neil Ravenscroft
      Streptococcus pneumoniae is a significant pathogen in children. Although the PCV7 pneumococcal conjugate vaccine has reduced pneumococcal disease, non-vaccine serotype 19A infection has increased, despite expectations of cross-protection from vaccine serotype 19F. Serotype 19A is included in the new PCV13 vaccine, but not in PCV10. In the solution simulations of 19F and 19A oligosaccharide chains reported here, both polysaccharides form unstructured random coils, with inflexible repeat units linked by mobile phosphodiester linkages. However, there are clear conformational differences. In the 19F repeat unit, the rhamnose residue is nearly orthogonal to the other residues, whereas 19A has residues in similar orientations. This finding is corroborated by key inter-residue distances calculated from NMR NOESY experiments. Further, 19F is predominantly in extended conformations, whereas 19A exhibits a high prevalence of tight hairpin bends. These conformational differences may account for a lack of antibody cross-protection between serotypes 19F and 19A.
      Graphical abstract image

      PubDate: 2015-01-27T11:49:39Z
       
  • Synthesis, emulsification and self-assembly properties of sugar-containing
           semifluorinated amphiphiles
    • Abstract: Publication date: Available online 13 January 2015
      Source:Carbohydrate Research
      Author(s): Andrew V. Razgulin , Sandro Mecozzi
      Surfactants with two and three monosaccharide-based heads and a perfluoroalkyl tail have been synthesized. Perfluoroalkyl C3-symmetric triol and C2-symmetric diol were conveniently prepared via Cu-catalyzed azide-alkyne cycloaddition between a fluorous alkyne and tertiary and secondary azides, respectively. Glycosylation of the perfluoroalkyl diol and triol led to orthoester-type structures, which were evaluated for their capacity to stabilize aqueous emulsions of highly fluorinated anesthetics. The self-assembly properties of the tri-sugar amphiphile were examined by transmission electron microscopy.
      Graphical abstract image

      PubDate: 2015-01-27T11:49:39Z
       
  • Editorial board
    • Abstract: Publication date: 12 January 2015
      Source:Carbohydrate Research, Volume 401




      PubDate: 2015-01-27T11:49:39Z
       
  • Graphical contents list
    • Abstract: Publication date: 12 January 2015
      Source:Carbohydrate Research, Volume 401




      PubDate: 2015-01-27T11:49:39Z
       
  • Force fields and scoring functions for carbohydrate simulation
    • Abstract: Publication date: 12 January 2015
      Source:Carbohydrate Research, Volume 401
      Author(s): Xiuming Xiong , Zhaoqiang Chen , Benjamin P. Cossins , Zhijian Xu , Qiang Shao , Kai Ding , Weiliang Zhu , Jiye Shi
      Carbohydrate dynamics plays a vital role in many biological processes, but we are not currently able to probe this with experimental approaches. The highly flexible nature of carbohydrate structures differs in many aspects from other biomolecules, posing significant challenges for studies employing computational simulation. Over past decades, computational study of carbohydrates has been focused on the development of structure prediction methods, force field optimization, molecular dynamics simulation, and scoring functions for carbohydrate–protein interactions. Advances in carbohydrate force fields and scoring functions can be largely attributed to enhanced computational algorithms, application of quantum mechanics, and the increasing number of experimental structures determined by X-ray and NMR techniques. The conformational analysis of carbohydrates is challengeable and has gone into intensive study in elucidating the anomeric, the exo-anomeric, and the gauche effects. Here, we review the issues associated with carbohydrate force fields and scoring functions, which will have a broad application in the field of carbohydrate-based drug design.
      Graphical abstract image

      PubDate: 2015-01-27T11:49:39Z
       
  • Chemical approach for the syntheses of GM4 isomers with sialic acid to
           non-natural linkage positions on galactose
    • Abstract: Publication date: 12 January 2015
      Source:Carbohydrate Research, Volume 401
      Author(s): Kenta Kurimoto , Hatsuo Yamamura , Atsushi Miyagawa
      Cell-surface glycans containing sialic acid are involved in various biological phenomena. However, the syntheses of GM4 derivatives with (2→2) and (2→4) linkages have not been investigated to date. In this study, sialylation of all of the hydroxyl groups on galactose were investigated for the syntheses of GM4 isomers. Regioselective sialylation was achieved via protection of galactosyl acceptors using electron-rich benzyl groups. These synthetic sialylated glycans will prove to be useful tools for studying unidentified carbohydrate-mediated biological roles.
      Graphical abstract image

      PubDate: 2015-01-27T11:49:39Z
       
  • Regioselectivity in the formation of di- and tri-6-O-mesitylenesulfonates
           of α-cyclodextrin
    • Abstract: Publication date: 12 January 2015
      Source:Carbohydrate Research, Volume 401
      Author(s): Keisuke Yoshikiyo , Misaki Shinjo , Yoshihisa Matsui , Tatsuyuki Yamamoto
      The quantitative analysis of the reaction products for α-cyclodextrin (α-CD) with mesitylenesulfonyl chloride (MessCl) showed that di- and tri-mesitylenesulfonylation of the primary hydroxy groups of α-CD is regioselective. The reaction of mono-6-O-mesitylenesulfonyl-α-CD with MessCl in pyridine gave less 6A,6C-di-O-mesitylenesulfonyl-α-CD than 6A,6B-di-O-mesitylenesulfonyl-α-CD. The reaction of 6A,6D-di-O-mesitylenesulfonyl-α-CD with MessCl gave less 6A,6B,6E-tri-O-mesitylenesulfonyl-α-CD than 6A,6B,6D-tri-O-mesitylenesulfonyl-α-CD. These results indicate that the mesitylenesulfonyl group attached to glucopyranose-A (Glc-A) retards further mesitylenesulfonylation of the primary hydroxy group of Glc-C. The 1H NMR spectra of these modified α-CDs showed that the signal for the primary hydroxy and anomeric protons of Glc-C are significantly shifted upfield by the mesitylenesulfonyl group of Glc-A.
      Graphical abstract image

      PubDate: 2015-01-27T11:49:39Z
       
  • A Linear Synthesis of Gemcitabine
    • Abstract: Publication date: Available online 14 January 2015
      Source:Carbohydrate Research
      Author(s): Kylie Brown , Alex Weymouth-Wilson , Bruno Linclau
      Gemcitabine, 2’-deoxy-2’,2’-difluorocytidine, is currently prescribed against a number of cancers. Here we report a linear synthesis of gemcitabine with a high-yielding direct conversion of 3,5-di-O-benzoyl-2-deoxy-2,2-difluororibose into the corresponding glycosyl urea as the key step, followed by conventional conversion to the cytosine base via the uracil derivative. The process proceeded with modest anomeric selectivity.
      Graphical abstract image

      PubDate: 2015-01-19T08:17:53Z
       
 
 
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