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  Subjects -> CHEMISTRY (Total: 846 journals)
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CHEMISTRY (597 journals)                  1 2 3 | Last

Showing 1 - 200 of 735 Journals sorted alphabetically
2D Materials     Hybrid Journal   (Followers: 7)
Accreditation and Quality Assurance: Journal for Quality, Comparability and Reliability in Chemical Measurement     Hybrid Journal   (Followers: 26)
ACS Catalysis     Full-text available via subscription   (Followers: 31)
ACS Chemical Neuroscience     Full-text available via subscription   (Followers: 17)
ACS Combinatorial Science     Full-text available via subscription   (Followers: 23)
ACS Macro Letters     Full-text available via subscription   (Followers: 22)
ACS Medicinal Chemistry Letters     Full-text available via subscription   (Followers: 39)
ACS Nano     Full-text available via subscription   (Followers: 215)
ACS Photonics     Full-text available via subscription   (Followers: 10)
ACS Synthetic Biology     Full-text available via subscription   (Followers: 20)
Acta Chemica Iasi     Open Access   (Followers: 2)
Acta Chimica Sinica     Full-text available via subscription  
Acta Chimica Slovaca     Open Access   (Followers: 1)
Acta Chromatographica     Full-text available via subscription   (Followers: 9)
Acta Facultatis Medicae Naissensis     Open Access  
Acta Metallurgica Sinica (English Letters)     Hybrid Journal   (Followers: 5)
Acta Scientifica Naturalis     Open Access   (Followers: 2)
adhäsion KLEBEN & DICHTEN     Hybrid Journal   (Followers: 5)
Adhesion Adhesives & Sealants     Hybrid Journal   (Followers: 7)
Adsorption Science & Technology     Full-text available via subscription   (Followers: 5)
Advanced Functional Materials     Hybrid Journal   (Followers: 47)
Advanced Science Focus     Free   (Followers: 3)
Advances in Chemical Engineering and Science     Open Access   (Followers: 53)
Advances in Chemical Science     Open Access   (Followers: 12)
Advances in Chemistry     Open Access   (Followers: 12)
Advances in Colloid and Interface Science     Full-text available via subscription   (Followers: 18)
Advances in Drug Research     Full-text available via subscription   (Followers: 22)
Advances in Enzyme Research     Open Access   (Followers: 10)
Advances in Fluorine Science     Full-text available via subscription   (Followers: 8)
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Advances in Heterocyclic Chemistry     Full-text available via subscription   (Followers: 8)
Advances in Materials Physics and Chemistry     Open Access   (Followers: 18)
Advances in Nanoparticles     Open Access   (Followers: 12)
Advances in Organometallic Chemistry     Full-text available via subscription   (Followers: 15)
Advances in Polymer Science     Hybrid Journal   (Followers: 40)
Advances in Protein Chemistry     Full-text available via subscription   (Followers: 18)
Advances in Protein Chemistry and Structural Biology     Full-text available via subscription   (Followers: 18)
Advances in Quantum Chemistry     Full-text available via subscription   (Followers: 5)
Advances in Science and Technology     Full-text available via subscription   (Followers: 10)
African Journal of Bacteriology Research     Open Access  
African Journal of Chemical Education     Open Access   (Followers: 2)
African Journal of Pure and Applied Chemistry     Open Access   (Followers: 7)
Agrokémia és Talajtan     Full-text available via subscription   (Followers: 2)
Alkaloids: Chemical and Biological Perspectives     Full-text available via subscription   (Followers: 3)
AMB Express     Open Access   (Followers: 1)
Ambix     Hybrid Journal   (Followers: 3)
American Journal of Biochemistry and Biotechnology     Open Access   (Followers: 65)
American Journal of Biochemistry and Molecular Biology     Open Access   (Followers: 14)
American Journal of Chemistry     Open Access   (Followers: 25)
American Journal of Plant Physiology     Open Access   (Followers: 13)
American Mineralogist     Full-text available via subscription   (Followers: 12)
Analyst     Full-text available via subscription   (Followers: 38)
Angewandte Chemie     Hybrid Journal   (Followers: 153)
Angewandte Chemie International Edition     Hybrid Journal   (Followers: 203)
Annales UMCS, Chemia     Open Access   (Followers: 1)
Annals of Clinical Chemistry and Laboratory Medicine     Open Access   (Followers: 1)
Annual Reports in Computational Chemistry     Full-text available via subscription   (Followers: 3)
Annual Reports Section A (Inorganic Chemistry)     Full-text available via subscription   (Followers: 3)
Annual Reports Section B (Organic Chemistry)     Full-text available via subscription   (Followers: 7)
Annual Review of Chemical and Biomolecular Engineering     Full-text available via subscription   (Followers: 12)
Annual Review of Food Science and Technology     Full-text available via subscription   (Followers: 14)
Anti-Infective Agents     Hybrid Journal   (Followers: 3)
Antiviral Chemistry and Chemotherapy     Hybrid Journal  
Applied Organometallic Chemistry     Hybrid Journal   (Followers: 6)
Applied Spectroscopy     Full-text available via subscription   (Followers: 22)
Applied Surface Science     Hybrid Journal   (Followers: 26)
Arabian Journal of Chemistry     Open Access   (Followers: 6)
ARKIVOC     Open Access   (Followers: 2)
Asian Journal of Biochemistry     Open Access   (Followers: 1)
Atomization and Sprays     Full-text available via subscription   (Followers: 3)
Australian Journal of Chemistry     Hybrid Journal   (Followers: 7)
Autophagy     Hybrid Journal   (Followers: 2)
Avances en Quimica     Open Access   (Followers: 1)
Biochemical Pharmacology     Hybrid Journal   (Followers: 9)
Biochemistry     Full-text available via subscription   (Followers: 276)
Biochemistry Insights     Open Access   (Followers: 5)
Biochemistry Research International     Open Access   (Followers: 6)
BioChip Journal     Hybrid Journal  
Bioinorganic Chemistry and Applications     Open Access   (Followers: 9)
Bioinspired Materials     Open Access   (Followers: 3)
Biointerface Research in Applied Chemistry     Open Access   (Followers: 2)
Biointerphases     Open Access   (Followers: 1)
Biology, Medicine, & Natural Product Chemistry     Open Access  
Biomacromolecules     Full-text available via subscription   (Followers: 18)
Biomass Conversion and Biorefinery     Partially Free   (Followers: 10)
Biomedical Chromatography     Hybrid Journal   (Followers: 6)
Biomolecular NMR Assignments     Hybrid Journal   (Followers: 3)
BioNanoScience     Partially Free   (Followers: 4)
Bioorganic & Medicinal Chemistry     Hybrid Journal   (Followers: 106)
Bioorganic & Medicinal Chemistry Letters     Hybrid Journal   (Followers: 99)
Bioorganic Chemistry     Hybrid Journal   (Followers: 10)
Biopolymers     Hybrid Journal   (Followers: 18)
Biosensors     Open Access   (Followers: 2)
Biotechnic and Histochemistry     Hybrid Journal   (Followers: 1)
Bitácora Digital     Open Access  
Boletin de la Sociedad Chilena de Quimica     Open Access  
Bulletin of the Chemical Society of Ethiopia     Open Access   (Followers: 2)
Bulletin of the Chemical Society of Japan     Full-text available via subscription   (Followers: 24)
Bulletin of the Korean Chemical Society     Hybrid Journal   (Followers: 1)
C - Journal of Carbon Research     Open Access   (Followers: 2)
Canadian Association of Radiologists Journal     Full-text available via subscription   (Followers: 2)
Canadian Journal of Chemistry     Full-text available via subscription   (Followers: 10)
Canadian Mineralogist     Full-text available via subscription   (Followers: 3)
Carbohydrate Research     Hybrid Journal   (Followers: 26)
Carbon     Hybrid Journal   (Followers: 67)
Catalysis for Sustainable Energy     Open Access   (Followers: 6)
Catalysis Reviews: Science and Engineering     Hybrid Journal   (Followers: 8)
Catalysis Science and Technology     Free   (Followers: 6)
Catalysis Surveys from Asia     Hybrid Journal   (Followers: 3)
Catalysts     Open Access   (Followers: 7)
Cellulose     Hybrid Journal   (Followers: 7)
Cereal Chemistry     Full-text available via subscription   (Followers: 4)
ChemBioEng Reviews     Full-text available via subscription   (Followers: 1)
ChemCatChem     Hybrid Journal   (Followers: 8)
Chemical and Engineering News     Free   (Followers: 12)
Chemical Bulletin of Kazakh National University     Open Access  
Chemical Communications     Full-text available via subscription   (Followers: 69)
Chemical Engineering Research and Design     Hybrid Journal   (Followers: 23)
Chemical Research in Chinese Universities     Hybrid Journal   (Followers: 3)
Chemical Research in Toxicology     Full-text available via subscription   (Followers: 19)
Chemical Reviews     Full-text available via subscription   (Followers: 163)
Chemical Science     Open Access   (Followers: 21)
Chemical Technology     Open Access   (Followers: 15)
Chemical Vapor Deposition     Hybrid Journal   (Followers: 4)
Chemical Week     Full-text available via subscription   (Followers: 7)
Chemie in Unserer Zeit     Hybrid Journal   (Followers: 55)
Chemie-Ingenieur-Technik (Cit)     Hybrid Journal   (Followers: 25)
ChemInform     Hybrid Journal   (Followers: 7)
Chemistry & Biodiversity     Hybrid Journal   (Followers: 6)
Chemistry & Biology     Full-text available via subscription   (Followers: 30)
Chemistry & Industry     Hybrid Journal   (Followers: 5)
Chemistry - A European Journal     Hybrid Journal   (Followers: 138)
Chemistry - An Asian Journal     Hybrid Journal   (Followers: 15)
Chemistry and Materials Research     Open Access   (Followers: 17)
Chemistry Central Journal     Open Access   (Followers: 4)
Chemistry Education Research and Practice     Free   (Followers: 5)
Chemistry in Education     Open Access   (Followers: 9)
Chemistry International     Hybrid Journal   (Followers: 2)
Chemistry Letters     Full-text available via subscription   (Followers: 43)
Chemistry of Materials     Full-text available via subscription   (Followers: 189)
Chemistry of Natural Compounds     Hybrid Journal   (Followers: 9)
Chemistry-Didactics-Ecology-Metrology     Open Access  
ChemistryOpen     Open Access   (Followers: 2)
Chemkon - Chemie Konkret, Forum Fuer Unterricht Und Didaktik     Hybrid Journal  
Chemoecology     Hybrid Journal   (Followers: 2)
Chemometrics and Intelligent Laboratory Systems     Hybrid Journal   (Followers: 15)
Chemosensors     Open Access  
ChemPhysChem     Hybrid Journal   (Followers: 8)
ChemPlusChem     Hybrid Journal   (Followers: 2)
ChemTexts     Hybrid Journal  
CHIMIA International Journal for Chemistry     Full-text available via subscription   (Followers: 2)
Chinese Journal of Chemistry     Hybrid Journal   (Followers: 6)
Chinese Journal of Polymer Science     Hybrid Journal   (Followers: 10)
Chromatographia     Hybrid Journal   (Followers: 23)
Chromatography Research International     Open Access   (Followers: 7)
Clay Minerals     Full-text available via subscription   (Followers: 9)
Cogent Chemistry     Open Access  
Colloid and Interface Science Communications     Open Access  
Colloid and Polymer Science     Hybrid Journal   (Followers: 10)
Colloids and Surfaces B: Biointerfaces     Hybrid Journal   (Followers: 8)
Combinatorial Chemistry & High Throughput Screening     Hybrid Journal   (Followers: 3)
Combustion Science and Technology     Hybrid Journal   (Followers: 18)
Comments on Inorganic Chemistry: A Journal of Critical Discussion of the Current Literature     Hybrid Journal   (Followers: 2)
Composite Interfaces     Hybrid Journal   (Followers: 6)
Comprehensive Chemical Kinetics     Full-text available via subscription   (Followers: 2)
Comptes Rendus Chimie     Full-text available via subscription  
Comptes Rendus Physique     Full-text available via subscription   (Followers: 1)
Computational and Theoretical Chemistry     Hybrid Journal   (Followers: 9)
Computational Biology and Chemistry     Hybrid Journal   (Followers: 12)
Computational Chemistry     Open Access   (Followers: 2)
Computers & Chemical Engineering     Hybrid Journal   (Followers: 9)
Coordination Chemistry Reviews     Full-text available via subscription   (Followers: 2)
Copernican Letters     Open Access  
Critical Reviews in Biochemistry and Molecular Biology     Hybrid Journal   (Followers: 5)
Crystal Structure Theory and Applications     Open Access   (Followers: 3)
CrystEngComm     Full-text available via subscription   (Followers: 10)
Current Catalysis     Hybrid Journal   (Followers: 2)
Current Metabolomics     Hybrid Journal   (Followers: 4)
Current Opinion in Colloid & Interface Science     Hybrid Journal   (Followers: 9)
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Current Science     Open Access   (Followers: 48)
Dalton Transactions     Full-text available via subscription   (Followers: 18)
Detection     Open Access   (Followers: 2)
Developments in Geochemistry     Full-text available via subscription   (Followers: 2)
Diamond and Related Materials     Hybrid Journal   (Followers: 11)
Dislocations in Solids     Full-text available via subscription  
Doklady Chemistry     Hybrid Journal  
Drying Technology: An International Journal     Hybrid Journal   (Followers: 3)
Eclética Química     Open Access   (Followers: 1)
Ecological Chemistry and Engineering S     Open Access   (Followers: 4)
Ecotoxicology and Environmental Contamination     Open Access  
Educación Química     Open Access   (Followers: 1)
Education for Chemical Engineers     Hybrid Journal   (Followers: 5)
EJNMMI Radiopharmacy and Chemistry     Open Access  
Elements     Full-text available via subscription   (Followers: 2)
Environmental Chemistry     Hybrid Journal   (Followers: 8)
Environmental Chemistry Letters     Hybrid Journal   (Followers: 4)
Environmental Science & Technology Letters     Full-text available via subscription   (Followers: 5)
Environmental Science : Nano     Partially Free   (Followers: 1)
Environmental Toxicology & Chemistry     Hybrid Journal   (Followers: 19)

        1 2 3 | Last

Journal Cover Carbohydrate Research
  [SJR: 0.612]   [H-I: 98]   [26 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 0008-6215 - ISSN (Online) 0008-6215
   Published by Elsevier Homepage  [3031 journals]
  • Stereospecific synthesis of methyl
           2-amino-2-deoxy-(6S)-deuterio-α,β-d-glucopyranoside and methyl
           2,6-diamino-2,6-dideoxy-(6R)-deuterio-α,β-d-glucopyranoside: Side chain
           conformations of the 2-amino-2-deoxy and
           2,6-diamino-2,6-dideoxyglucopyranosides
    • Abstract: Publication date: Available online 19 May 2017
      Source:Carbohydrate Research
      Author(s): Takayuki Kato, Andrea Vasella, David Crich
      The stereospecifically labeled 6-monodeuterio methyl 2,6-diamino-2,6-dideoxy-α- and β- d-glucopyranosides were synthesized with a view to determining their side chain conformations. NMR studies in D2O at pH 5 and pH 11 reveal both anomers to adopt very predominantly the gt conformation consistent with the gauche conformation of 2-aminoethanol and its acetate salt. In contrast, as also revealed with the help of stereospecifically-labelled monodeuterio iostopomers, the methyl 2-amino-2-deoxy-α- and β- d-glucopyranosides are an approximately 1:1 mixture of gg and gt conformers as is found in glucopyranose itself.
      Graphical abstract image

      PubDate: 2017-05-21T15:38:34Z
       
  • Conformational studies of N-(α-d-glucofuranurono-6,3-lactone)- and
           N-(methyl β-d-glucopyranuronate)-p-nitroanilines
    • Abstract: Publication date: Available online 19 May 2017
      Source:Carbohydrate Research
      Author(s): Dominik Walczak, Andrzej Nowacki, Damian Trzybiński, Justyna Samaszko-Fiertek, Henryk Myszka, Artur Sikorski, Beata Liberek
      N-(α-d-Glucofuranurono-6,3-lactone)-p-nitroaniline and N-(methyl β-d-glucopyranuronate)-p-nitroaniline were obtained as crystalline solids. The single-crystal X-ray diffraction, NMR data and DFT calculations for N-(α-d-glucofuranurono-6,3-lactone)-p-nitroaniline indicate that this N-furanoside adopts a 3 T 2/3 E-like conformation in the crystal lattice, solution and gas phase. Thus, the structure of recorded for N-furanoside 1H NMR spectrum is indicative of the 3 T 2 / 3 E region of the pseudorotational itinerary for furanose derivatives with α-d-gluco, β-L-ido and α-d-xylo configurations. Moreover, it is concluded that the 1 T 2/E 2/3 T 2/3 E region of the pseudorotational itinerary for furanose derivatives with d-gluco, L-ido and d-xylo configurations should be characterised by the lack of coupling between H2 and H3 protons, irrespective of the anomeric configuration. Such a lack of vicinal coupling is characteristic for some of the trans-oriented furanose ring protons. The single-crystal X-ray diffraction and NMR data for N-(methyl β-d-glucopyranuronate)-p-nitroaniline indicate that this N-glucuronide adopts the 4 C 1 conformation, both in the crystal lattice and solution. The occurrence of anomeric effects in the presented N-glycosides is discussed. The crystal structure analysis of both N-glycosides gives evidence that the amine group in p-nitroaniline is planar due to the nitrogen sp 2 hybridisation.
      Graphical abstract image

      PubDate: 2017-05-21T15:38:34Z
       
  • Fungal secretomics to probe the biological functions of lytic
           polysaccharide monooxygenases
    • Abstract: Publication date: Available online 17 May 2017
      Source:Carbohydrate Research
      Author(s): Jean-Guy Berrin, Marie-Noëlle Rosso, Maher Abou Hachem
      Enzymatic degradation of plant biomass is of growing interest for the development of a sustainable bio-based industry. Filamentous fungi, which degrade complex and recalcitrant plant polymers, are proficient secretors of enzymes acting on the lignocellulose composite of plant cell walls in addition to starch, the main carbon storage reservoir. In this review, we focus on the identification of lytic polysaccharide monooxygenases (LPMOs) and their redox partners in fungal secretomes to highlight the biological functions of these remarkable enzyme systems and we discuss future trends related to LPMO-potentiated bioconversion.
      Graphical abstract image

      PubDate: 2017-05-21T15:38:34Z
       
  • Enzymatic synthesis and semi-preparative isolation of N-acetylmuramic acid
           6-phosphate
    • Abstract: Publication date: 5 June 2017
      Source:Carbohydrate Research, Volume 445
      Author(s): Sandra Unsleber, Marina Borisova, Christoph Mayer
      N-acetylmuramic acid 6-phosphate (MurNAc-6P) is a constituent of the bacterial peptidoglycan cell wall, serving as an anchor point of secondary cell wall polymers such as teichoic acids, and it is a key metabolite of the peptidoglycan recycling metabolism. Thus, there is a demand for MurNAc-6P as a standard for cell wall compositional and metabolic analyses and, in addition, as a substrate for peptidoglycan recycling enzymes, e.g. MurNAc-6P etherases (MurQ) and MurNAc-6P phosphatases (MupP), or as an effector molecule of transcriptional MurR regulators. However, MurNAc-6P is commercially not available. We report here the facile enzymatic production of MurNAc-6P in mg-scale from MurNAc and ATP, applying Clostridium acetobutylicum kinase MurK, and purification by semi-preparative HPLC. MurNAc-6P was quantified using a coupled enzyme assay, revealing 75–80% overall product yield, and high purity was confirmed by mass spectrometry and proton NMR.
      Graphical abstract image

      PubDate: 2017-05-16T18:15:05Z
       
  • New structural insights into the oligosaccharide phosphate fraction of
           Pichia (Hansenula) holstii NRRL Y2448 phosphomannan
    • Abstract: Publication date: Available online 13 May 2017
      Source:Carbohydrate Research
      Author(s): Paul N. Handley, Anthony Carroll, Vito Ferro
      The oligosaccharide phosphate fraction (OPF) obtained from mild acid hydrolysis of P. holstii NRRL Y-2448 phosphomannan is the starting material for the preparation of the Phase III anticancer drug candidate PI-88. The OPF was for the first time successfully separated by preparative ion exchange chromatography and the major oligosaccharides isolated and characterized by NMR spectroscopy. The components were also acetylated and subjected to LC-MS analysis. These studies revealed that the OPF also contained all-α(1 → 3)-linked oligosaccharides in addition to the known α(1 → 3)/(1 → 2)-linked species, most likely formed by hydrolysis of the latter. Contrary to previous assumptions, the only phosphorylated disaccharide present is α(1 → 3)-linked. In addition, it was determined that a glycosylamine derivative previously isolated is, in fact, a manufacturing byproduct formed from exposure to aqueous ammonium bicarbonate during chromatographic purification. Based on these findings a new generic structure for PI-88 is proposed which more accurately reflects its composition.
      Graphical abstract image

      PubDate: 2017-05-16T18:15:05Z
       
  • Oxidation of 3,5-di-C-(per-O-acetylglucopyranosyl)phloroacetophenone in
           the synthesis of hydroxysafflor yellow A
    • Abstract: Publication date: Available online 13 May 2017
      Source:Carbohydrate Research
      Author(s): Toshiyuki Suzuki, Mitsuo Ishida, Toshihiro Kumazawa, Shingo Sato
      In the synthesis of the main yellow pigment hydroxysafflor yellow A (HSYA), that is present in safflower petals, the key compound 4-(S)-2-acetyl-4,6-di-C-(per-O-acetyl-β-D-glucosyl)-3,4-dihydroxy-5-methoxycyclohexa-2,5-dienone (11b) was diastereoselectively synthesized in an overall yield of 18% from di-C-β-D-glucosylphloroacetophenone per-O-acetate (8).
      Graphical abstract image

      PubDate: 2017-05-16T18:15:05Z
       
  • Enzymatic synthesis of novel corylifol A glucosides via a
           UDP-glycosyltransferase
    • Abstract: Publication date: Available online 11 May 2017
      Source:Carbohydrate Research
      Author(s): Nan Li, Jian Miao, Jing Li, Yu-Ru Zhao, Hong-Mei Li, Yi-Qun Dai, Qiang Huo, Cheng-Zhu Wu, Tao Ma
      Corylifol A, a member of the isoflavone subclass of isoflavonoids, has long been considered to have various biological activities. Here, we sought to synthesize corylifol A glucosides by the in vitro glucosylation reaction using the UDP-glycosyltransferase YjiC from Bacillus licheniformis DSM 13, and obtained two novel glucosides: corylifol A-4′,7-di-O-beta-d-glucopyranoside (1) and corylifol A-4′-O-beta-d-glucopyranoside (2). To improve the yield of the products, the reaction time, concentration of UDP-glucose, and pH of the buffer were optimized. The Michaelis constant (Km) was calculated to be 2.88 mM, and the maximal velocity (Vmax) was calculated to be 77.32 nmol/min/mg for UDP-glycosyltransferase. Meanwhile, the water-solubility of compounds 1 and 2 was approximately 27.03 and 15.13 times higher, respectively, than that of their parent compound corylifol A. Additionally, the corylifol A glycosylated products exhibited the highest stability at pH 9.6 and better temperature stability than corylifol A at 40, 60, 80 and 100 °C. In addition, cytotoxicity activity assays against three human tumor cell lines, only corylifol A showed moderate anti-proliferative activity. Overall, this work demonstrates that glycosylation can enhance the water solubility and stability of promising compounds, with potential for further development and application.
      Graphical abstract image

      PubDate: 2017-05-11T18:59:42Z
       
  • Isomerization of glucose into fructose by environmentally friendly
           Fe/β zeolite catalysts
    • Abstract: Publication date: Available online 10 May 2017
      Source:Carbohydrate Research
      Author(s): Siquan Xu, Lei Zhang, Kehao Xiao, Haian Xia
      Herein, the environmentally friendly Fe/β zeolite for glucose isomerization to fructose in aqueous media was reported for the first time. The effects of various reaction conditions including reaction temperature, reaction time, catalyst dosage, etc. on the isomerization reaction over Fe/β zeolite were studied in detail. Under the optimized conditions, yield of fructose higher than 20% were obtained. Moreover, the Fe/β zeolite catalysts were stable and remained constant catalytic activity after five consecutive runs. The possible active Fe species for isomerization of glucose in Fe/β zeolite is also discussed.
      Graphical abstract image

      PubDate: 2017-05-11T18:59:42Z
       
  • Cross-protection in Neisseria meningitidis serogroups Y and W
           polysaccharides: A comparative conformational analysis
    • Abstract: Publication date: Available online 10 May 2017
      Source:Carbohydrate Research
      Author(s): Michelle M. Kuttel, Zaheer Timol, Neil Ravenscroft
      The capsular polysaccharide is the main virulence factor in meningococcus. The capsular polysaccharides for meningococcal serogroups Y and W are almost identical polymers of hexose-sialic acid, suggesting the possibility of cross-protection between group Y and W vaccines. However, early studies indicated that they elicit different levels of cross-protection. Here we explore the conformations of the meningococcal Y and W polysaccharides with molecular dynamics simulations of three repeating unit oligosaccharide strands. We find differences in Y and W antigen conformation: the Y polysaccharide has a single dominant conformation, whereas W exhibits a family of conformations including the Y conformation. This result is supported by our NMR NOESY analysis, which indicates key close contacts for W that are not present in Y. These conformational differences provide an explanation for the different levels of cross-protection measured for the Y and W monovalent vaccines and the high group W responses observed in HibMenCY-TT vaccinees.
      Graphical abstract image

      PubDate: 2017-05-11T18:59:42Z
       
  • Graphical contents list
    • Abstract: Publication date: 18 April–12 May 2017
      Source:Carbohydrate Research, Volumes 443–444


      PubDate: 2017-05-11T18:59:42Z
       
  • Stereoselective acetylation of hemicellulosic C5-sugars
    • Abstract: Publication date: 18 April–12 May 2017
      Source:Carbohydrate Research, Volumes 443–444
      Author(s): Zachary D. Herde, Prathap D. John, Dania Alvarez-Fonseca, Jagannadh Satyavolu, Christopher T. Burns
      The stereoselective peracetylation of α-d-xylose (1) and α-l-arabinose (4) using a combination of triethylamine and acetic anhydride in the presence or absence of a catalytic amount of dimethylaminopyridine (DMAP) is described. The peracetylated d-xylose and l-arabinose alpha pyranose anomers 2α and 5α are obtained in 97% and 56% yields respectively. The peracetylated d-xylose beta pyranose anomer 2β is obtained in 71% yield through simple modification of the reaction conditions. Details regarding synthesis and isolation optimization studies under different conditions are presented below. The stereoselective peracetylation reactions disclosed here have been used to separate mixtures of d-xylose and l-arabinose as their peracetylated derivatives 2β and 5α in 47% and 42% yields and can provide pure pentoses after deacetylation.
      Graphical abstract image

      PubDate: 2017-05-11T18:59:42Z
       
  • N-Substituted 5-amino-1-hydroxymethyl-cyclopentanetriols: A new family of
           activity promotors for a GM1-gangliosidosis related human lysosomal
           β-galactosidase mutant
    • Abstract: Publication date: 18 April–12 May 2017
      Source:Carbohydrate Research, Volumes 443–444
      Author(s): Michael Schalli, Christina Tysoe, Roland Fischer, Bettina M. Pabst, Martin Thonhofer, Eduard Paschke, Tanja Rappitsch, Arnold E. Stütz, Marion Tschernutter, Werner Windischhofer, Stephen G. Withers
      From 1,2;3,4-di-O-isopropylidene-α-D-galactopyranose, a series of highly functionalized (hydroxymethyl)cyclopentanes was easily available. In line with reports by Reymond and Jäger on similar structures, these amine containing basic carbasugars are potent inhibitors of β-D-galactosidases and, for the first time, could be shown to act as pharmacological chaperones for GM1-gangliosidosis-associated lysosomal acid β-galactosidase mutant R201C, thus representing a new structural type of pharmacological chaperones for this lysosomal storage disease.
      Graphical abstract image

      PubDate: 2017-05-11T18:59:42Z
       
  • Exhaustive rotamer search of the 4C1 conformation of α- and
           β-d-galactopyranose
    • Abstract: Publication date: Available online 6 May 2017
      Source:Carbohydrate Research
      Author(s): Enrique A. Del Vigo, Carla Marino, Carlos A. Stortz
      An exhaustive search approach was used to establish all possible rotamers of α- and β-d-galactopyranose using DFT at the B3LYP/6-311+G** and M06-2X/6-311+G** levels, both in vacuum calculations, and including two variants of continuum solvent models as PCM and SMD to simulate water solutions. Free energies were also calculated. MM3 was used as the starting point for calculations, using a dielectric constant of 1.5 for vacuum modeling, and 80 for water solution modeling. For the vacuum calculations, out the theoretically possible 729 rotamers, only about a hundred rendered stable minima, highly stabilized by hydrogen bonding and scattered in a ca. 14 kcal/mol span. The rotamer with a clockwise arrangement of hydrogen bonds was the most stable for the α-anomer, whereas that with a counterclockwise arrangement was the most stable for the β-anomer. Free energy calculations, and especially solvent modeling, tend to flatten the potential energy surface. With PCM, the total range of energies was reduced to 9–10 kcal/mol (α-anomer) or 7–8 kcal/mol (β-anomer). These figures fall to 4.5–6 kcal/mol using SMD. At the same time, the total number of possible rotamers increases dramatically to about 300 with PCM, and to 400 with SMD. Both models show a divergent behavior: PCM tends to underestimate the effect of solvent, thus rendering as the most stable many common rotamers with vacuum calculations, and giving underestimations of populations of β-anomers and gt rotamers in the equilibrium. On the other hand, SMD gives a better estimation of the solvent effect, yielding correct populations of gt rotamers, but more β-anomers than expected by the experimental values. The best agreement is observed when the functional M06-2X is combined with SMD. Both DFT models show minimal geometrical differences between the optimized conformers.
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      PubDate: 2017-05-06T23:06:20Z
       
  • Glycoengineering and glycosite-specific labeling of serum IgGs from
           various species
    • Abstract: Publication date: Available online 4 May 2017
      Source:Carbohydrate Research
      Author(s): Weilai Guo, Feng Tang, Ken Qin, Mang Zhou, Zhiping Le, Wei Huang
      Chemoenzymatic glycoengineering of immunoglobulin G (IgG) catalyzed by Endo-S is a powerful approach to remodel the heterogeneous N-glycoforms of Fc domain with a homogeneous synthetic glycan structure for enhanced Fc receptor-mediated effector functions. The previous researches on the method development mainly focused on human or humanized IgGs with therapeutic potentials. Here, for the first time we report the extended application of this method on glycan-remodeling of serum IgGs from other species including rabbit, mouse, and goat. Harnessing an azido-tagged non-natural N-glycan substrate and successive click reaction, glycosite-specific fluorescent labeling of IgGs was enabled. This study provided a new avenue for glycoengineering and Fc-specific labeling of IgGs with minimized influence on antigen-binding domains, and this method was adaptive to thousands of commercial antibody reagents from various species with great application potentials.
      Graphical abstract image

      PubDate: 2017-05-06T23:06:20Z
       
  • Glycerol mycolates from synthetic mycolic acids
    • Abstract: Publication date: Available online 2 May 2017
      Source:Carbohydrate Research
      Author(s): Omar T. Ali, Mohaned M. Sahb, Juma'a R. Al Dulayymi, Mark S. Baird
      R- and S-Glycerol mycolates derived from single synthetic α-, keto- and methoxy-mycolic acids are described.
      Graphical abstract image

      PubDate: 2017-05-06T23:06:20Z
       
  • Structure and gene cluster of the O-antigen of Escherichia albertii O1
           resembling the O-antigen of Pseudomonas aeruginosa O5
    • Abstract: Publication date: Available online 2 May 2017
      Source:Carbohydrate Research
      Author(s): Han Zheng, Alexander S. Shashkov, Yanwen Xiong, Olesya I. Naumenko, Hong Wang, Sof'ya N. Senchenkova, Jianping Wang, Yuriy A. Knirel
      The O-specific polysaccharide (O-antigen) was obtained by mild acid degradation of the lipopolysaccharide of Escherichia albertii serotype O1 strain EP312 and studied by sugar analysis along with 1D and 2D 1H and 13C NMR spectroscopy. The following structure was established for the trisaccharide repeating unit of the O-polysaccharide: →4)-β-d-ManpNAc3NAcA-(1 → 4)-β-d-GlcpNAm3NAcA-(1 → 3)-α-d-GlcpNAc-(1→ where ManNAc3NAcA and GlcNAm3NAcA indicate 2,3-diacetamido-2,3-dideoxymannuronic acid and 2-acetimidoylamino-3-acetamido-2,3-dideoxyglucuronic acid, respectively. While showing some similarity with O-polysaccharide structures of a group of Pseudomonas aeruginosa serotypes (O2, O5, O16, O18, and O20), that of E. albertii O1 is unique among known bacterial polysaccharide structures. The gene cluster for biosynthesis of the O1-antigen was sequenced and functions of the genes were predicted by comparison with sequences in the available databases, including those involved in the synthesis of nucleotide precursors of 2,3-diamino-2,3-dideoxyhexuronic acid derivatives in P. aeruginosa O5.
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      PubDate: 2017-05-06T23:06:20Z
       
  • Rapid and robust enzymatic sensing and quantitation of
           3,6-Anhydro-L-galactose in a heterogeneous sugar mixture
    • Abstract: Publication date: Available online 28 April 2017
      Source:Carbohydrate Research
      Author(s): Duleepa Pathiraja, Kyoung Heon Kim, In-Geol Choi
      3,6-Anhydro-L-galactose (L-AHG) is a rare sugar found in agar polysaccharides. L-AHG has been used as a bioactive compound over the past few years. While the chromatographic or mass-spectrometric quantitation of L-AHG is quite sensitive and accurate, these methods require a reference standard and an intensive sample preparation procedure. We developed an enzymatic assay for rapid and robust quantitation of L-AHG using anhydrogalactose dehydrogenase cloned from Vibrio sp. EJY3 (VejAHGD). VejAHGD is a NADP+ - dependent enzyme which catalyzes the oxidation of L-AHG with a stoichiometric ratio of 1:1. Kinetic characterization of the enzyme showed a Km value of 0.19 ± 0.01 mM. The activity of the enzyme was optimum at 20 °C and pH 8.0. The half-life of enzymatic activity was 12 h under optimum condition. VejAHGD was highly specific to L-AHG, such that the reaction was not interfered by a variety of mono- or oligo-sugars in a heterogeneous mixture. Except transition metal ions, other cations or chelating agents did not affect the activity of the enzyme. Detection limit of the assay was 0.2 mM at 340 nm in the spectrophotometry. The assay was so rapid to give the result less than 5 min, requiring neither separation nor pretreatment of samples. We suggest application of the assay for detection and quantitation of L-AHG in commercial products and biosensor development.
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      PubDate: 2017-05-01T07:46:22Z
       
  • Gold(I)-catalyzed synthesis of β-Kdo glycosides using Kdo
           ortho-hexynylbenzoate as donor
    • Abstract: Publication date: Available online 28 April 2017
      Source:Carbohydrate Research
      Author(s): Xuemeng Mi, Qixin Lou, Wenjing Fan, Liqin Zhuang, You Yang
      A gold(I)-catalyzed glycosylation of Kdo with glycosyl ortho-hexynylbenzoate as donor is reported. The couplings of Kdo ortho-hexynylbenzoate with a set of alcohols promoted by PPh3AuOTf afford Kdo glycosides with good β-selectivities. This glycosylation method allows for the synthesis of β-Kdo monosaccharide with a C5 linker at the reducing end for subsequent conjugation to carrier proteins and arrays.
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      PubDate: 2017-05-01T07:46:22Z
       
  • Synthesis of D-fructose conjugated ligands via C6 and C1 and their
           corresponding [Ru(bpy)2(L)]Cl2 complexes
    • Abstract: Publication date: Available online 27 April 2017
      Source:Carbohydrate Research
      Author(s): Michael Pröhl, Pascal D. Moser, Justyna A. Czaplewska, Patrick Hoffmann, Tanja Bus, Anja Traeger, Helmar Görls, Ulrich S. Schubert, Michael Gottschaldt
      A pyridyl triazole (pyta) modified sucrose ligand was prepared in a seven step synthesis using D-glucose as the protection group for D-fructose and starting from commercially available sucrose. After complexation with Ru(bpy)2Cl2 precursor, the sucrose-conjugated Ru complex of the general formula [Ru(bpy)2(L)]Cl2 was formed. Acidic cleavage of the D-glucose unit led to the first D-fructose conjugated metal complex via D-fructose C6 in literature. Additionally, pyta-modified D-fructose via C1 and the corresponding Ru complex were synthesized. All compounds were analyzed by Rf values, specific rotation, NMR, IR, UV/Vis and fluorescence spectroscopy, mass spectrometry and elemental analysis.
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      PubDate: 2017-05-01T07:46:22Z
       
  • Hydrophobicity of carbohydrates and related hydroxy compounds
    • Abstract: Publication date: Available online 27 April 2017
      Source:Carbohydrate Research
      Author(s): Christoph Buttersack
      The hydrophobic interaction of carbohydrates and other hydroxy compounds with a C18-modified silica gel column was measured with pure water as eluent, thereby expanding the range of measurements already published. The interaction is augmented by structure strengthening salts and decreasing temperature. Although the interaction of the solute with the hydrophobic interface is expected to only imperfectly reflect its state in aqueous bulk solution, the retention can be correlated to hydration numbers calculated from molecular mechanics studies given in the literature. No correlation can be established towards published hydration numbers obtained by physical methods (isentropic compressibility, O-17 NMR relaxation, terahertz spectroscopy, and viscosity). The hydrophobicity is discussed with respect to the chemical structure. It increases with the fraction and size of hydrophobic molecular surface regions.
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      PubDate: 2017-05-01T07:46:22Z
       
  • Ring-opening polymerization of new 3-O-branched 1, 6-anhydro glucopyranose
           di- and trisaccharide monomers
    • Abstract: Publication date: Available online 22 April 2017
      Source:Carbohydrate Research
      Author(s): Chaolumen Bai, Davaanyam Budragchaa, Takashi Yoshida
      New 3-O-branched 1, 6-anhydro glucopyranose disaccharide monomers, 1, 6-anhydro-2, 4-di-O- benzyl-3-O-(2′, 3′, 4′, 6'-tetra-O-benzyl-α-D-mannopyranosyl)- (LGM 6) and -glucopyranosyl)-β-D- glucopyranose (LGG 7), and a trisaccharide monomer, 1, 6-anhydro-2, 4-di-O-benzyl-3-O-α-(2′, 3′, 6′, 2″, 3″, 4″, 6″-hepta-O-benzyl- α-D-maltopyranosyl)-β-D-glucopyranose (LGMAL 8), were synthesized and polymerized. It was found that the 3-O-branched1, 6-anhydro disaccharide monomers were polymerized. However, the polymerizability was lower than that of the 4-O-branched disaccharide monomers reported previously, and the trisaccharide monomer was not polymerizable, probably due to the steric hindrance of the branched bulky mono and disaccharide units at the 3-O position in 1, 6-anhydro glucopyranose. Debenzylation of the resulting polymers gave 3-O-gluco- and mannopyranosidic (1 → 6)-α-D-glucopyranans in moderate yields. These results are the first reports of the polymerization of 3-O-branched 1, 6-anhydro glucopyranose disaccharide monomers to give 3-O-branched polysaccharides.
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      PubDate: 2017-04-24T07:35:35Z
       
  • Implementation of GlycanBuilder to draw a wide variety of ambiguous
           glycans
    • Abstract: Publication date: Available online 19 April 2017
      Source:Carbohydrate Research
      Author(s): Shinichiro Tsuchiya, Nobuyuki P. Aoki, Daisuke Shinmachi, Masaaki Matsubara, Issaku Yamada, Kiyoko F. Aoki-Kinoshita, Hisashi Narimatsu
      GlyTouCan version 1.0 was released in 2015 as the international glycan structure repository, and a new sequence format called WURCS (Web3 Unique Representation of Carbohydrate Structures) was proposed during the early stages of the GlyTouCan project. GlyTouCan uses WURCS as its base representation for glycans because existing formats were insufficient in their flexibility to represent any and all glycans universally. Therefore, in order to obtain WURCS strings for existing or new glycan structures, conversion tools or glycan structure editors that can export WURCS became necessary. GlycanBuilder was an obvious choice to extend due to its wide usage by the community. However, GlycanBuilder was limited because it was originally developed to support mammalian glycans. It also did not support the newly proposed monosaccharide symbol standard called Symbol Nomenclature for Glycans (SNFG). Therefore in this work, we implemented a new version of GlycanBuilder to greatly increase its usability. The glycan rendering system was refactored so that cyclic glycans, nested repeating units, monosaccharide compositions and cross-linked glycan structures can be represented. Both import and export utilities for WURCS were also implemented and SNFG symbols were incorporated to allow glycans to be exported as graphics using the latest glycan symbol nomenclature. This new version of GlycanBuilder called “GlycanBuilder2”, is able to support a wide variety of ambiguous glycans, including structures containing monosaccharides from bacteria and plants. These glycans can also be displayed using the new SNFG symbols. This tool can aid researchers in communicating about the complex, diverse, and ambiguous structures of glycans more rapidly. Moreover, the new GlycanBuilder can now easily output WURCS sequences from glycans drawn on the canvas. Most importantly, because GlyTouCan employs WURCS as the basic format for registration and searching of glycan information, a wider variety of glycans can now be readily registered and queried in GlyTouCan.
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      PubDate: 2017-04-24T07:35:35Z
       
  • Cladolosides I1, I2, J1, K1, K2 and L1, monosulfated triterpene glycosides
           with new carbohydrate chains from the sea cucumber Cladolabes schmeltzii
    • Abstract: Publication date: Available online 19 April 2017
      Source:Carbohydrate Research
      Author(s): Alexandra S. Silchenko, Anatoly I. Kalinovsky, Sergey A. Avilov, Pelageya V. Andryjaschenko, Pavel S. Dmitrenok, Ekaterina A. Chingizova, Igor Yu. Dolmatov, Vladimir I. Kalinin
      Six new monosulfated triterpene glycosides, cladolosides I1 (1), I2 (2), J1 (3), K1 (4), K2 (5) and L1 (6) were isolated from the tropical Indo-West Pacific sea cucumber Cladolabes schmeltzii (Cladolabinae, Sclerodactylidae, Dendrochirotida). Structures of these glycosides were elucidated by 2D NMR spectroscopy and mass spectrometry. Four new types of carbohydrate chains have been found in 1–6. Cladolosides of the groups I and J are characterized by pentasaccharide carbohydrate chains sulfated at a terminal 3-O-methylglucose residue and branched by the position 4 of the first xylose residue, but differing from each other in the lengths of the main and side carbohydrate chains. Cladolosides of the groups K and L contain hexasaccharide chains with different positions of a sulfated terminal 3-O-methylglucose residue (as the fourth or the sixth monosaccharide residue). Sulfated hexasaccharide carbohydrate chains were found in the sea cucumbers glycosides for the first time. A pentasaccharide carbohydrate chain of cladoloside J1 (3) having a disaccharide moiety of glucose and a sulfated 3-O-methylglucose linked to the first xylose residue in a linear trisaccharide fragment is also unusual. All substances studied demonstrated strong or moderate hemolytic and cytotoxic effects.
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      PubDate: 2017-04-24T07:35:35Z
       
  • Synthesis of novel C-4ʹ-spiro-oxetano-α-L-ribonucleosides
    • Abstract: Publication date: Available online 19 April 2017
      Source:Carbohydrate Research
      Author(s): Rajesh Kumar, Manish Kumar, Ankita Singh, Neetu Singh, Jyotirmoy Maity, Ashok K. Prasad
      The synthesis of novel C-4ʹ-spiro-oxetano-α-L-ribonucleosides T and U in 39 and 45% overall yields have been achieved from 2′,3′,5′-tri-O-acetyl-4′-C-p-toluenesulfonyloxymethyl-β-D-xylofuranosylthymine and 2′,3′,5′-tri-O-acetyl-4′-C-p-toluenesulfonyloxymethyl-β-D-xylofuranosyluracil, respectively. Both the tosylated nucleoside precursors have been synthesized following recently developed Novozyme®-435 catalyzed methodology.
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      PubDate: 2017-04-24T07:35:35Z
       
  • Synthesis and revised stereochemical assignment of C-allyl
           glucopyranosides and derivatives
    • Abstract: Publication date: 5 June 2017
      Source:Carbohydrate Research, Volume 445
      Author(s): Nicolas Petry, Timothé Vucko, Charlotte Collet, Sandrine Lamandé-Langle, Nadia Pellegrini-Moïse, Françoise Chrétien
      α- and β-C-allylglucopyranosides and hydroxy-, bromo- and azido-derivatives were prepared through allylation at C-1 of methyl 2,3,4,6-tetra-O-benzyl-D-glucopyranoside or 1-O-acetyl-2,3,4,6-tetra-O-benzyl-D-glucopyranose and subsequent chemical modifications of the alkene on the anomeric arm. However, we picked out some discordance between some recent published studies and our results. After a thorough work of characterization and NMR analysis, we unambiguously confirmed α and β stereochemistry of the two series of compounds and fully described for the first time β-C-propyl alcohol, bromide and azide of 2,3,4,6-tetra-O-benzyl-D-glucopyranose.
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      PubDate: 2017-04-17T07:28:24Z
       
  • Flavanonol glucosides from the aerial parts of Agrimonia pilosa Ledeb. and
           their acetylcholinesterase inhibitory effects
    • Abstract: Publication date: Available online 15 April 2017
      Source:Carbohydrate Research
      Author(s): U. Min Seo, Duc Hung Nguyen, Bing Tian Zhao, Byung Sun Min, Mi Hee Woo
      Two new flavanonol glucoside isomers, (2R,3S)-dihydrokaempferol 3-O-β-D-glucoside (1) and (2S,3R)-dihydrokaempferol 3-O-β-D-glucoside (2), were isolated from the aerial parts of Agrimonia pilosa Ledeb., along with eight known flavanonol glucosides (3–10). Their structures were determined on the basis of spectroscopic analysis. In addition, these compounds were evaluated to determine their acetylcholinesterase inhibitory activities. The results indicated that these compounds have moderate inhibitory effects, with IC50 values ranging from 76.59 ± 1.16 to 97.53 ± 1.64 μM, except compounds 1 and 4 were inactive.
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      PubDate: 2017-04-17T07:28:24Z
       
  • Structure and gene cluster of a tyvelose-containing O-polysaccharide of an
           entomopathogenic bacterium Yersinia entomophaga MH96T related to Yersinia
           pseudotuberculosis
    • Abstract: Publication date: Available online 15 April 2017
      Source:Carbohydrate Research
      Author(s): O.V. Sizova, A.N. Kondakova, A.S. Shashkov, Y.A. Knirel, R.Z. Shaikhutdinova, S.A. Ivanov, M.E. Platonov, M.R.H. Hurst, S.V. Dentovskaya
      An O-polysaccharide was isolated from the lipopolysaccharide of an entomopathogenic bacterium Yersinia entomophaga MH96T by mild acid hydrolysis and studied by 2D NMR spectroscopy. The following structure of the branched tetrasaccharide repeating unit of the polysaccharide was established: Image 2 where Tyv indicates 3,6-dideoxy-d-arabino-hexose (tyvelose). The structure established is consistent with the gene content of the O-antigen gene cluster. The O-polysaccharide structure and gene cluster of Y. entomophaga are related to those of some Y. pseudotuberculosis serotypes.
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      PubDate: 2017-04-17T07:28:24Z
       
  • Reactivity studies in water on the acid-catalysed dehydration of psicose
           compared to other ketohexoses into 5-hydroxymethylfurfural
    • Abstract: Publication date: Available online 13 April 2017
      Source:Carbohydrate Research
      Author(s): Robert-Jan van Putten, Jan C. van der Waal, Ed de Jong, Hero J. Heeres
      The conversion of the four possible ketohexoses (fructose, tagatose, sorbose and psicose) into 5-hydroxymethylfurfural (HMF) was explored in water using sulphuric acid as the catalyst (33 mM H2SO4, 120 °C). Significant differences in reactivity were observed and tagatose (48% conversion after 75 min) and psicose (35% conversion after 75 min) were clearly more reactive than fructose and sorbose (around 20% conversion after 75 min). The selectivity to HMF was found to be higher for fructose and psicose than for tagatose and sorbose. 2-Hydroxyacetylfuran (HAF) was shown to be a by-product for mainly sorbose and tagatose (as high as 2% yield). The results indicate that the relative orientation of the hydroxyl groups on C3 and C4 has a major effect on the reactivity and selectivity. This suggests that the dehydration towards HMF takes place via a mechanism with cyclic intermediates in which the C3-C4 bond is fixed in a ring structure. A reaction mechanism involving a bicyclic structure is proposed to explain the formation of HAF. The reactivity of the sugars was significantly lower in water than previously observed in methanol.
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      PubDate: 2017-04-17T07:28:24Z
       
  • Improved quantification of monosaccharides in complex lignocellulosic
           biomass matrices: A gas chromatography-mass spectrometry based approach
    • Abstract: Publication date: Available online 13 April 2017
      Source:Carbohydrate Research
      Author(s): Thomas Zweckmair, Sonja Schiehser, Thomas Rosenau, Antje Potthast
      A novel method for the precise and accurate quantification of wood monosaccharides by gas-chromatography mass-spectrometry in complex lignocellulosic biomass matrices is presented. Instead of using the syn- or the anti peak obtained by blocking the anomeric center using e.g. oximation, the sum of each syn- and anti-peak pair is used for quantification rendering the approach independent from an apparently constant syn- and anti-peak area ratio. Each wood monosaccharide syn- and anti-peak could essentially be distinguished upon O-ethoximation followed by trifluoroacetylation and separation on a 14% cyanopropyl/phenyl- 86% dimethylpoly-siloxane column. Additionally, internal standardization is carried out applying isotopically labeled compounds. Hence, the analytical figures of merit such as precision and accuracy in biorefinery sample matrices could be substantially improved compared to standard gas-chromatography mass spectrometry as well as high-performance anion exchange chromatography (HPAEC) coupled to pulsed-amperometric detection (PAD) techniques. The applicability of the novel gas-chromatography mass-spectrometry approach is demonstrated analyzing five selected lignocellulosic biomass sample matrices typically occurring in a biorefinery scenario. Even in heavily loaded sample matrices precise and accurate data is obtained when using the novel methodology presented.
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      PubDate: 2017-04-17T07:28:24Z
       
  • A bioinformatics analysis of 3400 lytic polysaccharide oxidases from
           family AA9
    • Abstract: Publication date: Available online 13 April 2017
      Source:Carbohydrate Research
      Author(s): Nicolas Lenfant, Matthieu Hainaut, Nicolas Terrapon, Elodie Drula, Vincent Lombard, Bernard Henrissat
      Lytic polysaccharide monooxygenases of family AA9 catalyze the oxidative cleavage of glycosidic bonds in cellulose and related polysaccharides. The N-terminal half of AA9 LPMOs displays a huge sequence variability that is in contradiction with the substrate simplicity so far observed for these enzymes. To understand the cause of the high multigenicity that prevails in the family, we have performed a clustering analysis of the N-terminal region of 3400 sequences of family AA9 LPMOs, and have evaluated the coincidence of the clusters with distal visible features that may accompany functional differences. A method based on local pairwise alignments was devised to avoid the pitfalls of a global multiple alignment. Our analysis allowed the definition of 64 clusters, which successfully segregated several visible features associated to LPMO family AA9, such as the presence of carbohydrate-binding modules, of modules of unknown function and of the conspicuous H > R substitution at the first residue of the histidine brace that holds the catalytic copper. Our analysis shows that the hypervariability of the N-terminal half of the AA9 sequences is not driven by random evolution as sequence similarity does not follow solely taxonomy. The results suggest that some clusters are perhaps able to target chitin instead of cellulose, and that preference for C1 or C4 oxidation (or lack thereof), does not appear to constitute a strong evolutionary constraint. On an evolutionary standpoint, there seems to be little constraints that apply to the N-terminal half of the sequences other than the conservation of the histidine brace. The weak evolutionary constraints that apply to the N-terminal half of AA9 LPMOs explain both their hypervariability and multigenicity.
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      PubDate: 2017-04-17T07:28:24Z
       
  • A glucose-sensitive block glycopolymer hydrogel based on dynamic boronic
           ester bonds for insulin delivery
    • Abstract: Publication date: 5 June 2017
      Source:Carbohydrate Research, Volume 445
      Author(s): Baoqi Cai, Yanping Luo, Qianqian Guo, Xinge Zhang, Zhongming Wu
      Hydrogels are good candidates to satisfy many needs for functional and tunable biomaterials. How to precisely control the gel structure and functions is crucial for the construction of sophisticated soft biomaterials comprising the hydrogels, which facilitates the impact of the surrounding environment on a unique biological function occurring. Here, glucose-responsive hydrogels comprised of 3-acrylamidophenyl boronic acid copolymerized with 2-lactobionamidoethyl methacrylate (p(APBA-b-LAMA)) were synthesized, and further evaluated as carriers for insulin delivery. The formation of (p(APBA-b-LAMA)) hydrogel was based on dynamic covalent bond using the association of boronic acid with diols. P(APBA-b-LAMA) hydrogel with the typical porous structure showed a rapid increase in equilibrium of swelling, which was up to 1856% after incubation with aqueous solution. Using insulin as a model protein therapeutic, p(APBA-b-LAMA) hydrogel exhibited high drug loading capability up to 15.6%, and also displayed glucose-dependent insulin release under physiological conditions. Additionally, the viability of NIH3T3 cells was more than 90% after treated with p(APBA-b-LAMA) hydrogel, indicating that the hydrogel had no cytotoxicity. Consequently, the novel p(APBA-b-LAMA) hydrogel has a practical application for diabetes treatment.
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      PubDate: 2017-04-10T18:16:14Z
       
  • Characterization of O-antigen polysaccharide backbone derived from nitric
           oxide-inducing Mesorhizobium loti MAFF 303099 lipopolysaccharide
    • Abstract: Publication date: 5 June 2017
      Source:Carbohydrate Research, Volume 445
      Author(s): Masahito Hashimoto, Masato Mizukami, Ken-ichi Osuki, Nagatoshi Fujiwara, Yasuo Suda, Toshiki Uchiumi
      Mesorhizobium loti is a member of rhizobia and establishes nitrogen-fixing symbioses with several Lotus species. Recently, we reported that M. loti MAFF 303099 bacterial cells and their lipopolysaccharide (LPS) preparations are involved in the beginning of the symbiotic process by inducing transient nitric oxide (NO) production in the roots of L. japonicus. We subsequently found that both the polysaccharide (PS) part and the lipid A moiety in LPS are responsible for the NO induction. In this study, we elucidated the chemical structure of M. loti O-polysaccharide (OPS) in PS. PS was prepared by mild acid hydrolysis of M. loti LPS followed by gel filtration chromatography. OPS was subjected to hydrazine treatment to obtain deacylated PS (dPS). Chemical composition analysis, ethylation analysis, and NMR spectra revealed the chemical structure of the M. loti OPS backbone in dPS to be →2)-α-l-6dTalp-(1 → 3)-α-l-6dTalp-(1 → 2)-α-l-Rhap-(1 → 2)-α-l-6dTalp-(1 → 3)-α-l-6dTalp-(1 → 3)-α-l-Rhap-(1→.
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      PubDate: 2017-04-10T18:16:14Z
       
  • Determination of mole fractions of ethyl-cellulose-containing monomers by
           NMR
    • Abstract: Publication date: 5 June 2017
      Source:Carbohydrate Research, Volume 445
      Author(s): Hiroyuki Kono
      Three samples of ethyl cellulose (EC) with different degrees of substitution (DS)—0.51, 1.41, and 2.28—were prepared by a slurry method using ethyl bromide as the etherification reagent. 1H–13C HSQC and HSQC-TOCSY NMR spectral analysis allowed for complete assignment of the 1H and 13C chemical shifts, respectively, of eight anhydroglucose units (AGUs) comprising EC chains—un-, 2-mono-, 3-mono-, 6-mono-, 2,3-di-, 2,6-di-, 3,6-di-, and 2,3,6-tri-substituted AGUs. In addition, the lineshape of the quantitative 13C NMR spectra of the three EC samples provided change in the mole fractions of these AGUs against DS, making it possible to estimate the reaction mechanism for the production of EC, elucidating reactivities of the hydroxyl groups at the 2, 3, and 6 positions of cellulose and interactions between the substituent groups within the same AGU and vicinal AGUs.
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      PubDate: 2017-04-10T18:16:14Z
       
  • Identification and biochemical characterization of a novel
           α-1,3-mannosyltransferase WfcD from Escherichia coli O141
    • Abstract: Publication date: 18 April–12 May 2017
      Source:Carbohydrate Research, Volumes 443–444
      Author(s): Chao Chen, Xi Hou, Natalia Utkina, Leonid Danilov, Dawei Zhou, Vladimir Torgov, Vladimir Veselovsky, Bin Liu, Lu Feng
      Glycosyltransferases (GTs) catalyze the formation of regio- and stereospecific glycosidic linkages between specific sugar donors and recipients. In this study, the function of the wfcD gene from the Escherichia coli O141 O-antigen gene cluster encoding an α-1,3-mannosyltransferase that catalyzed the formation of the linkage Man(α1-3)-GlcNAc was biochemically characterized. WfcD was expressed in E. coli BL21 (DE3), and the enzymatic product was identified by liquid chromatography-mass spectrometry (LC-MS), collision-induced dissociation electrospray ionization ion trap multiple tandem MS (CID-ESI-IT-MSn) and glycosidase digestion using the donor substrate GDP-Man and the synthetic acceptor substrate decyl diphosphate 2-acetamido-2-deoxy-α-D-glucopyranose (GlcNAc-PP-De). The kinetic and physiochemical properties and the substrate specificity of WfcD were investigated. WfcD is the first characterized bacterial mannosyltransferase that acts on the Man(α1-3)-GlcNAc linkage. This study enhances our knowledge of the diverse functions of GTs.
      Graphical abstract image

      PubDate: 2017-04-10T18:16:14Z
       
  • Studies on the 6-homologation of β-D-idopyranosides
    • Abstract: Publication date: Available online 8 April 2017
      Source:Carbohydrate Research
      Author(s): Rachel Hevey, Chang-Chun Ling
      β-D-Idopyranosides are interesting sugars because of their unusual conformational flexibility in the pyranosyl ring, and also their β-1,2-cis-anomeric configuration. Here we report on studies of the regioselective opening of 4,6-O-benzylidene-protected β-D-idopyranosides under reducing conditions, and the subsequent 6-homologation via Swern oxidation and Wittig olefination to afford a 6,7-dideoxy-β-D-ido-hept-6-enopyranoside. This olefination product was found to adopt predominantly 1C4 conformation in solution by NMR experiments, which places the vinyl group at a more sterically hindered axial position and creates difficulty in subsequent hydroborations.
      Graphical abstract image

      PubDate: 2017-04-10T18:16:14Z
       
  • Cycloartane triterpenoid saponins from the herbs of Thalictrum fortunei
    • Abstract: Publication date: 5 June 2017
      Source:Carbohydrate Research, Volume 445
      Author(s): Si-Qi Jiang, Yu-Bo Zhang, Min Xiao, Lin Jiang, Ding Luo, Qian-Wen Niu, Yao-Lan Li, Xian-Tao Zhang, Guo-Cai Wang
      Six new cycloartane triterpenoid saponins, thalisides A-F (1–6), along with four known ones (7–10), were isolated from Thalictrum fortunei. The new structures were elucidated by using spectroscopic data (NMR, IR, UV, and MS). Compounds 1–10 were examined for their in vitro cytotoxicity against two human cancer cell lines (HepG2, A549) and antiviral activity against influenza A virus (H1N1) and found to be inactive.
      Graphical abstract image

      PubDate: 2017-04-02T16:54:14Z
       
  • The uniform structure of O-polysaccharides isolated from Dickeya solani
           strains of different origin
    • Abstract: Publication date: Available online 1 April 2017
      Source:Carbohydrate Research
      Author(s): Karolina Ossowska, Małgorzata Czerwicka, Wojciech Sledz, Sabina Zoledowska, Agata Motyka, Małgorzata Golanowska, Guy Condemine, Ewa Lojkowska, Zbigniew Kaczyński
      O-polysaccharides were isolated from lipopolysaccharides obtained from four different strains of plant pathogenic bacteria belonging to the species Dickeya solani: two of them were isolated in Poland (IFB0099 and IFB0158), the third in Germany (IFB0223) and the last one, D. solani Type Strain IPO2222, originated from the Netherlands. In addition, the O-polysaccharide of a closely related species D. dadantii strain 3937 was isolated. The purified polysaccharides of the five strains were analyzed using NMR spectroscopy and chemical methods. Sugar and methylation analyses, including absolute configuration assignment, together with NMR data revealed that all O-polysaccharides tested are homopolymers of 6-deoxy-d-altrose (d-6dAlt) the following structure: →2)-β-d-6dAltp-(1→
      Graphical abstract image

      PubDate: 2017-04-02T16:54:14Z
       
  • Synthesis of β-galactosylamides as ligands of the peanut lectin. Insights
           into the recognition process
    • Abstract: Publication date: Available online 23 March 2017
      Source:Carbohydrate Research
      Author(s): María Emilia Cano, Oscar Varela, María Isabel García-Moreno, José Manuel García Fernández, José Kovensky, María Laura Uhrig
      The synthesis of mono and divalent β-galactosylamides linked to a hydroxylated chain having a C2 symmetry axis derived from l-tartaric anhydride is reported. Reference compounds devoid of hydroxyl groups in the linker were also prepared from β-galactosylamine and succinic anhydride. After functionalization with an alkynyl residue, the resulting building blocks were grafted onto different azide-equipped scaffolds through the copper catalyzed azide-alkyne cycloaddition. Thus, a family of structurally related mono and divalent β-N-galactopyranosylamides was obtained and fully characterized. The binding affinities of the ligands towards the model lectin PNA were measured by the enzyme-linked lectin assay (ELLA). The IC50 values were significantly higher than that of galactose but the presence of hydroxyl groups in the aglycone chain improved lectin recognition. Docking and molecular dynamics experiments were in accordance with the hypothesis that a hydroxyl group properly disposed in the linker could mimic the Glc O3 in the recognition process. On the other hand, divalent presentation of the ligands led to lectin affinity enhancements.
      Graphical abstract image

      PubDate: 2017-03-26T16:48:08Z
       
  • Structure of the O-specific polysaccharide from a marine bacterium
           Cellulophaga algicola
    • Abstract: Publication date: Available online 22 March 2017
      Source:Carbohydrate Research
      Author(s): Svetlana V. Tomshich, Maxim S. Kokoulin, Anatoliy I. Kalinovsky, Ol'ga I. Nedashkovskaya, Nadezhda A. Komandrova
      The O-polysaccharide was isolated from the lipopolysaccharide of Cellulophaga algicola and studied by chemical analyses along with 1H and 13C NMR spectroscopy, including 2D 1H, 1H COSY, TOCSY, ROESY, 1Н, 13С HSQC, HMBC experiments. It was found that the polysaccharide is built up of branched pentasaccharide repeating units, containing D-mannose (Man), D-glucuronic acid (GlcA), N-acetyl-D-glucosamine (GlcNAc), two L-rhamnose (Rha) residues and O-acetyl groups in a non-stoichiometric amount and has the following structure: Image 2
      Graphical abstract image

      PubDate: 2017-03-26T16:48:08Z
       
  • Synthetic glyco-O-sulfatome for profiling of human natural antibodies
    • Abstract: Publication date: Available online 22 March 2017
      Source:Carbohydrate Research
      Author(s): Galina Pazynina, Marina Sablina, Tatiana Ovchinnikova, Tatiana Tyrtysh, Svetlana Tsygankova, Alexander Tuzikov, Kira Dobrochaeva, Nadezhda Shilova, Nailia Khasbiullina, Nicolai Bovin
      Our understanding of biological role of glycans O-sulfation remains at the level of beginners due to microheterogeneity, lability and other difficulties of exact structural assignment. Partially, problem of functional investigations, especially determination of glycoepitope specificity of carbohydrate-binding proteins could be solved with the help of synthetic glycans of certain structure. Here we summing up our synthetic efforts in creation of synthetic O-sulfatome, and bring together all the synthesized in our group sulfated glycans, both existing in nature, yet undiscovered but biochemically licit, and completely unnatural. All glycans have aminoalkyl spacer group allowing immobilization on a chip. We exemplify the capabilities of O-sulfoglycan microarray (containing >70 ligands) for profiling human natural antibodies; for a number of glycans O-sulfation dramatically changes interaction with human antibodies.
      Graphical abstract image

      PubDate: 2017-03-26T16:48:08Z
       
  • Convergent strategy for the synthesis of S-linked oligoxylans
    • Abstract: Publication date: Available online 21 March 2017
      Source:Carbohydrate Research
      Author(s): Beatrice Bonora, Irene Boos, Mads H. Clausen
      Arabinoxylans (AX) are a major class of hemicellulose and an important polysaccharide component of lignocellulosic biomass. To utilize the glycan polymer effectively, it is desirable to learn more about the enzymatic hydrolysis of AXs. Well-defined glycans can help to elucidate these processes. Here, we report the efficient synthesis of a mixed O- and S-linked tetraxylan. This thio-oligosaccharide has been developed as a putative inhibitor of arabinoxylan degrading enzymes used for the saccharification of biomass. Two common approaches for the synthesis of thio-oligosaccharides, either involving 1-thioglycoside donors or thioacceptors, are presented and compared regarding byproduct formation and yields. Both methods have shown to be useful for the synthesis of thiolinkages in oligoxylans assembly. However, the success of the reaction is highly dependent on the “match” between donors and acceptors.
      Graphical abstract image

      PubDate: 2017-03-26T16:48:08Z
       
  • Quantum mechanics models of the methanol dimer: O-H…O hydrogen bonds of
           β-d-glucose moieties from crystallographic data
    • Abstract: Publication date: Available online 19 March 2017
      Source:Carbohydrate Research
      Author(s): Michael Santiago Cintrón, Glenn P. Johnson, Alfred D. French
      The interaction of two methanol molecules, simplified models of carbohydrates and cellulose, was examined using a variety of quantum mechanics (QM) levels of theory. Energy plots for hydrogen bonding distance (H…O) and angle (O-H…O) were constructed. All but two experimental structures were located in stabilized areas on the vacuum phase energy plots. Each of the 399 models was analyzed with Bader's atoms-in-molecules (AIM) theory, which showed a widespread ability by the dimer models to form O-H…O hydrogen bonds that have bond paths and Bond Critical Points. Continuum solvation calculations suggest that a portion of the energy-stabilized structures could occur in the presence of water. A survey of the Cambridge Structural Database (CSD) for all donor-acceptor interactions in β-D-glucose moieties examined the similarities and differences among the hydroxyl groups and acetal oxygen atoms that participate in hydrogen bonds. Comparable behavior was observed for the O2-H, O3-H, O4-H, and O6-H hydroxyls, acting either as acceptors or donors. Ring O atoms showed distinct hydrogen bonding behavior that favored mid-length hydrogen bonds.
      Graphical abstract image

      PubDate: 2017-03-26T16:48:08Z
       
  • Heterologous expression, purification and characterization of three novel
           esterases secreted by the lignocellulolytic fungus Penicillium
           purpurogenum when grown on sugar beet pulp
    • Abstract: Publication date: Available online 18 March 2017
      Source:Carbohydrate Research
      Author(s): Gabriela Oleas, Eduardo Callegari, Romina Sepúlveda, Jaime Eyzaguirre
      The lignocellulolytic fungus, Penicillium purpurogenum, grows on a variety of natural carbon sources, among them sugar beet pulp. Culture supernatants of P. purpurogenum grown on sugar beet pulp were partially purified and the fractions obtained analyzed for esterase activity by zymograms. The bands with activity on methyl umbelliferyl acetate were subjected to mass spectrometry to identify peptides. The peptides obtained were probed against the proteins deduced from the genome sequence of P. purpurogenum. Eight putative esterases thus identified were chosen for future work. Their cDNAs were expressed in Pichia pastoris. The supernatants of the recombinant clones were assayed for esterase activity, and five of the proteins were active against one or more substrates: methyl umbelliferyl acetate, indoxyl acetate, methyl esterified pectin and fluorescein diacetate. Three of those enzymes were purified, further characterized and subjected to a BLAST search. Based on their amino acid sequence and properties, they were identified as follows: RAE1, pectin acetyl esterase (CAZy family CE 12); FAEA, feruloyl esterase (could not be assigned to a CAZy family) and EAN, acetyl esterase (former CAZy family CE 10).
      Graphical abstract image

      PubDate: 2017-03-18T16:40:12Z
       
  • Structural elucidation of a novel transglycosylated compound α-glucosyl
           rhoifolin and of α -glucosyl rutin by NMR spectroscopy
    • Abstract: Publication date: Available online 16 March 2017
      Source:Carbohydrate Research
      Author(s): Chisa Aoki, Yoshihiro Takeuchi, Kenjirou Higashi, Yuta Okamoto, Akihito Nakanishi, Mahamadou Tandia, Jun Uzawa, Keisuke Ueda, Kunikazu Moribe
      We report the full assignment of 1H and 13C NMR signals belonging to α-glucosyl rhoifolin (Rhf-G), a novel transglycosylated compound synthesized from a flavone glycoside, rhoifolin, as well as its chemical structure. Furthermore, we report the complete NMR signal assignment for another transglycosylated compound, α-glucosyl rutin (Rutin-G), as the signals corresponding to its sugar moieties had not been identified. Electrospray ionization-mass spectrometry along with multiple NMR methods revealed that Rhf-G possesses three sugar moieties in its chemical structure. The additional glucose was bound directly via a transglycosylation to rhoifolin at position 3a of the sugar moiety. Interestingly, intramolecular hydrogen bonds in the basic Rhf-G and Rutin-G skeletons were confirmed by HMBC experiments. These findings will be helpful for comprehensive NMR studies on transglycosylated compounds in food, cosmetic, and pharmaceutical fields.
      Graphical abstract image

      PubDate: 2017-03-18T16:40:12Z
       
  • Synthesis and conformational analysis of a simplified inositol-model of
           the Streptococcus pneumoniae 19F capsular polysaccharide repeating unit
    • Abstract: Publication date: Available online 14 March 2017
      Source:Carbohydrate Research
      Author(s): Giorgio Catelani, Felicia D'Andrea, Lorenzo Guazzelli, Alessio Griselli, Nicola Testi, Maria Assunta Chiacchio, Laura Legnani, Lucio Toma
      Carbohydrate mimics have been studied for a long time as useful sugar substitutes, both in the investigation of biological events and in the treatment of sugar-related diseases. Here we report further evaluation of the capabilities of inositols as carbohydrate substitutes. The conformational features of an inositol-model of a simplified repeating unit corresponding to the capsular polysaccharide of Streptococcus pneumoniae 19F has been evaluated by computational analysis, and compared to the native repeating unit. The inositol mimic was synthesized, and its experimental spectroscopic data allowed for verification of the theoretical results.
      Graphical abstract image

      PubDate: 2017-03-15T16:35:07Z
       
  • Synthesis and biological activities of C-glycosides of KRN 7000 with novel
           ceramide residues
    • Abstract: Publication date: Available online 6 March 2017
      Source:Carbohydrate Research
      Author(s): Ahmad S. Altiti, Xiaojing Ma, Lixing Zhang, Yi Ban, Richard W. Franck, David R. Mootoo
      The identification of immunoactive agents for clinical and mechanistic applications is a very active area of research. In this vein, analogues of the potent immunostimulant KRN 7000 with diverse cytokine profiles have attracted considerable attention. Herein, we report on the synthesis and activity for four new C-glycosides of KRN 7000, 11-phenylundecanoyl and 11-p-fluorophenylundecanoyl derivatives of C-KRN 7000, 2,3-bis-epi-C-KRN 7000 and the reverse amide of C-KRN 7000. In mice, compared to C-KRN 7000, 2,3-bis-epi-C-KRN 7000 stimulated higher release of the anti-inflammatory cytokine IL-4 and lower release of the inflammatory cytokines IFN-γ and IL-12. The phenyl terminated alkanoyl and reverse amide analogues were inactive. These data suggest that structure activity effects for KRN 7000 are not necessarily additive and their use in the design of new analogues will require an improved understanding of how subtle structural changes impact on cytokine activity.
      Graphical abstract image

      PubDate: 2017-03-08T11:04:32Z
       
  • Novel substrates for the automated and manual assay of
           endo-1,4-β-xylanase
    • Abstract: Publication date: Available online 4 March 2017
      Source:Carbohydrate Research
      Author(s): David Mangan, Claudio Cornaggia, Agnija Liadova, Niall McCormack, Ruth Ivory, Vincent A. McKie, Aaron Ormerod, Barry V. McCleary
      endo-1,4-β-Xylanase (EC 3.2.1.8) is employed across a broad range of industries including animal feed, brewing, baking, biofuels, detergents and pulp (paper). Despite its importance, a rapid, reliable, reproducible, automatable assay for this enzyme that is based on the use of a chemically defined substrate has not been described to date. Reported herein is a new enzyme coupled assay procedure, termed the XylX6 assay, that employs a novel substrate, namely 4,6-O-(3-ketobutylidene)-4-nitrophenyl-β-45-O-glucosyl-xylopentaoside. The development of the substrate and associated assay is discussed here and the relationship between the activity values obtained with the XylX6 assay versus traditional reducing sugar assays and its specificity and reproducibility were thoroughly investigated.
      Graphical abstract image

      PubDate: 2017-03-08T11:04:32Z
       
  • Stereoselective total synthesis of Oxylipin from open chain
           gluco-configured building block
    • Abstract: Publication date: Available online 3 March 2017
      Source:Carbohydrate Research
      Author(s): Santosh Ramdas Borkar, Indrapal Singh Aidhen
      Total synthesis of naturally occurring Oxylipin has been achieved from open chain gluco-configured building block which is readily assembled from inexpensive and commercially available D-(+)-gluconolactone. Grignard reaction and Wittig olefination reactions are key steps for the requisite CC bond formation.
      Graphical abstract image

      PubDate: 2017-03-08T11:04:32Z
       
  • Structural and genetic characterization of the O-antigen of Enterobacter
           cloacae C5529 related to the O-antigen of E. cloacae G3054
    • Abstract: Publication date: Available online 28 February 2017
      Source:Carbohydrate Research
      Author(s): Runhua Han, Andrei V. Perepelov, Yuanyuan Wang, Andrei V. Filatov, Min Wang, Alexander S. Shashkov, Lei Wang, Yuriy A. Knirel
      On mild acid degradation of the lipopolysaccharide of Enterobacter cloacae C5529, the O-polysaccharide chain was cleaved at the linkages of 5,7-diacetamido-3,5,7,9-tetradeoxy-l-glycero-l-manno-non-2-ulosonic acid (di-N-acetylpseudaminic acid, Pse5Ac7Ac). The resultant oligosaccharide and an alkali-treated lipopolysaccharide were studied by sugar analysis along with 1H and 13C NMR spectroscopy, and the following structure of the tetrasaccharide repeating unit of the O-polysaccharide was established: →4)-β-Pse5Ac7Ac-(2 → 3)-β-d-Galp-(1 → 6)-β-d-Galf-(1 → 3)-α-d-Galp-(1→ It differs from a structurally related O-polysaccharide of E. cloacae G3045 studied early (Perepelov, A. V.; Wang, M.; Filatov, A. V.; Guo, X.; Shashkov, A. S.; Wang, L.; Knirel, Y. A. Carbohydr. Res. 2015; 407:59–62) in positions of substitution of β-Psep5Ac7Ac (O-4 vs. O-8) and β-Galp (O-3 vs. O-6) and the absence of a side-chain α-Galp residue. The O-antigen gene clusters of E. cloacae C5529 and G3045 are organized identically and include genes with the same putative functions in the O-polysaccharide synthesis. Based on these and serological data, it is suggested to combine E. cloacae C5529 and G3054 in one O-serogroup as two subgroups.
      Graphical abstract image

      PubDate: 2017-03-01T17:07:47Z
       
 
 
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