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  Subjects -> CHEMISTRY (Total: 843 journals)
    - ANALYTICAL CHEMISTRY (47 journals)
    - CHEMISTRY (594 journals)
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CHEMISTRY (594 journals)                  1 2 3 4 5 6 | Last

2D Materials     Hybrid Journal   (Followers: 7)
Accreditation and Quality Assurance: Journal for Quality, Comparability and Reliability in Chemical Measurement     Hybrid Journal   (Followers: 27)
ACS Catalysis     Full-text available via subscription   (Followers: 28)
ACS Chemical Neuroscience     Full-text available via subscription   (Followers: 16)
ACS Combinatorial Science     Full-text available via subscription   (Followers: 17)
ACS Macro Letters     Full-text available via subscription   (Followers: 24)
ACS Medicinal Chemistry Letters     Full-text available via subscription   (Followers: 26)
ACS Nano     Full-text available via subscription   (Followers: 179)
ACS Photonics     Full-text available via subscription   (Followers: 5)
ACS Synthetic Biology     Full-text available via subscription   (Followers: 18)
Acta Chemica Iasi     Open Access  
Acta Chimica Sinica     Full-text available via subscription  
Acta Chimica Slovaca     Open Access   (Followers: 5)
Acta Chromatographica     Full-text available via subscription   (Followers: 8)
Acta Facultatis Medicae Naissensis     Open Access   (Followers: 1)
Acta Metallurgica Sinica (English Letters)     Hybrid Journal   (Followers: 7)
adhäsion KLEBEN & DICHTEN     Hybrid Journal   (Followers: 5)
Adhesion Adhesives & Sealants     Hybrid Journal   (Followers: 5)
Adsorption Science & Technology     Full-text available via subscription   (Followers: 10)
Advanced Functional Materials     Hybrid Journal   (Followers: 47)
Advanced Science Focus     Free   (Followers: 3)
Advances in Chemical Engineering and Science     Open Access   (Followers: 26)
Advances in Chemical Science     Open Access   (Followers: 10)
Advances in Chemistry     Open Access   (Followers: 4)
Advances in Colloid and Interface Science     Full-text available via subscription   (Followers: 14)
Advances in Drug Research     Full-text available via subscription   (Followers: 19)
Advances in Environmental Chemistry     Open Access   (Followers: 1)
Advances in Enzyme Research     Open Access   (Followers: 2)
Advances in Fluorine Science     Full-text available via subscription   (Followers: 8)
Advances in Fuel Cells     Full-text available via subscription   (Followers: 13)
Advances in Heterocyclic Chemistry     Full-text available via subscription   (Followers: 9)
Advances in Materials Physics and Chemistry     Open Access   (Followers: 15)
Advances in Nanoparticles     Open Access   (Followers: 11)
Advances in Organometallic Chemistry     Full-text available via subscription   (Followers: 11)
Advances in Polymer Science     Hybrid Journal   (Followers: 38)
Advances in Protein Chemistry     Full-text available via subscription   (Followers: 8)
Advances in Protein Chemistry and Structural Biology     Full-text available via subscription   (Followers: 12)
Advances in Quantum Chemistry     Full-text available via subscription   (Followers: 6)
Advances in Science and Technology     Full-text available via subscription  
African Journal of Chemical Education     Open Access   (Followers: 1)
African Journal of Pure and Applied Chemistry     Open Access   (Followers: 5)
Afrique Science : Revue Internationale des Sciences et Technologie     Open Access   (Followers: 1)
Agrokémia és Talajtan     Full-text available via subscription   (Followers: 1)
Alkaloids: Chemical and Biological Perspectives     Full-text available via subscription   (Followers: 4)
AMB Express     Open Access  
Ambix     Hybrid Journal   (Followers: 2)
American Journal of Applied Sciences     Open Access   (Followers: 33)
American Journal of Biochemistry and Biotechnology     Open Access   (Followers: 72)
American Journal of Biochemistry and Molecular Biology     Open Access   (Followers: 11)
American Journal of Chemistry     Open Access   (Followers: 25)
American Journal of Plant Physiology     Open Access   (Followers: 11)
American Mineralogist     Full-text available via subscription   (Followers: 7)
Analyst     Full-text available via subscription   (Followers: 40)
Angewandte Chemie     Hybrid Journal   (Followers: 30)
Angewandte Chemie International Edition     Hybrid Journal   (Followers: 142)
Annales UMCS, Chemia     Open Access   (Followers: 2)
Annals of Clinical Chemistry and Laboratory Medicine     Open Access   (Followers: 1)
Annual Reports in Computational Chemistry     Full-text available via subscription   (Followers: 2)
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: 10)
Annual Review of Food Science and Technology     Full-text available via subscription   (Followers: 13)
Anti-Infective Agents     Hybrid Journal   (Followers: 2)
Antiviral Chemistry and Chemotherapy     Full-text available via subscription   (Followers: 1)
Applied Organometallic Chemistry     Hybrid Journal   (Followers: 5)
Applied Spectroscopy     Full-text available via subscription   (Followers: 16)
Applied Surface Science     Hybrid Journal   (Followers: 23)
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: 5)
Autophagy     Hybrid Journal   (Followers: 3)
Avances en Quimica     Open Access   (Followers: 1)
Biochemical Pharmacology     Hybrid Journal   (Followers: 6)
Biochemistry     Full-text available via subscription   (Followers: 163)
Biochemistry Insights     Open Access   (Followers: 4)
Biochemistry Research International     Open Access   (Followers: 5)
BioChip Journal     Hybrid Journal   (Followers: 1)
Bioinorganic Chemistry and Applications     Open Access   (Followers: 6)
Bioinspired Materials     Open Access   (Followers: 1)
Biointerface Research in Applied Chemistry     Open Access   (Followers: 1)
Biointerphases     Open Access   (Followers: 1)
Biology, Medicine, & Natural Product Chemistry     Open Access  
Biomacromolecules     Full-text available via subscription   (Followers: 19)
Biomass Conversion and Biorefinery     Partially Free   (Followers: 8)
Biomedical Chromatography     Hybrid Journal   (Followers: 7)
Biomolecular NMR Assignments     Hybrid Journal   (Followers: 2)
BioNanoScience     Partially Free   (Followers: 3)
Bioorganic & Medicinal Chemistry     Hybrid Journal   (Followers: 32)
Bioorganic & Medicinal Chemistry Letters     Hybrid Journal   (Followers: 25)
Bioorganic Chemistry     Hybrid Journal   (Followers: 6)
Biopolymers     Hybrid Journal   (Followers: 16)
Biosensors     Open Access   (Followers: 2)
Biotechnic and Histochemistry     Hybrid Journal   (Followers: 3)
Boletin de la Sociedad Chilena de Quimica     Open Access  
Bulletin of the Chemical Society of Ethiopia     Open Access   (Followers: 3)
Bulletin of the Chemical Society of Japan     Full-text available via subscription   (Followers: 14)
C - Journal of Carbon Research     Open Access  
Cakra Kimia (Indonesian E-Journal of Applied Chemistry)     Open Access   (Followers: 1)
Canadian Association of Radiologists Journal     Full-text available via subscription   (Followers: 4)

        1 2 3 4 5 6 | Last

Journal Cover Carbohydrate Research
  [SJR: 0.654]   [H-I: 83]   [12 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 0008-6215 - ISSN (Online) 0008-6215
   Published by Elsevier Homepage  [2801 journals]
  • Marine cytotoxic jaspine b and its stereoisomers: biological activity and
           syntheses
    • Abstract: Publication date: Available online 27 January 2016
      Source:Carbohydrate Research
      Author(s): Miroslava Martinková, Jozef Gonda
      Conformationally constrained sphingolipids such as anhydrophytosphingosines represented by jaspine B (also known as pachastrissamine) and its stereoisomers have become an attractive and timely target for total synthesis due to their significant biological activity as well as the unique structures. This review article describes the biological activity and chemistry of the natural jaspine B and its seven stereoisomers.
      Graphical abstract image

      PubDate: 2016-02-01T19:40:06Z
       
  • Ring inversion properties of 1→2, 1→3 and 1→6-linked
           hexopyranoses and their correlation with the conformation of glycosidic
           linkages
    • Abstract: Publication date: Available online 28 January 2016
      Source:Carbohydrate Research
      Author(s): Wojciech Plazinski, Mateusz Drach, Anita Plazinska
      Enhanced-sampling molecular dynamics simulations performed within the GROMOS 56a6CARBO_R force field were applied in order to elucidate ring-inversion properties of hexopyranose residues in a chain for the case of α(1→n) and β(1→n) glycosidic linkages (n = 2, 3 or 6). The results indicate that ring-inversion free energies calculated for residues in a chain are weakly correlated with those of corresponding monomers, except of the case of 1→6 linkages. This, in combination with the results for O1-methyl-hexopyranosides [Plazinski et al. J. Comp. Chem. 2016, 37, 354;
      DOI : 10.1002/jcc.24229], suggests that both the type of functionalization (glycolysation vs. methylation) and the topology of glycosidic linkage play an important role in possible alterations of the hexopyranose ring flexibility. Additionally, the correlation of the ring shape with the preferred geometry of glycosidic linkages was investigated. The linkages of the 1→2, 1→3 and 1→6 types do not follow the trend found in the case of the 1→4 linkages, i.e. there is no correlation between the range of changes in the glycosidic linkage conformation and the topological orientation of the glycosidic oxygen atoms. Overall, the ring shape affects the glycosidic linkages of the 1→6 type to the least extent in comparison to the remaining ones.


      PubDate: 2016-02-01T19:40:06Z
       
  • Spiro sugar-isoxazolidine scaffold as useful polyfunctional building block
           for peptidomimetics design
    • Abstract: Publication date: Available online 22 January 2016
      Source:Carbohydrate Research
      Author(s): Mylène Richard, Yves Chapleur, Nadia Pellegrini-Moïse
      Spiro sugar-isoxazolidines obtained by 1,3-dipolar cycloaddition of activated exo-glycals and nitrones were efficiently functionalized at two sites, i.e. C-4 and C-7, with arginine, arginine mimetics and guanidylated appendages. Two bicyclic sugar derivatives differing by the configuration at C-7 were chosen as model compounds. The small library of peptidomimetics was evaluated toward inhibition of VEGF-A165/neuropilin-1 binding. Unexpected cleavage of C3-C4 bond of isoxazolidine moiety was observed during hydrogenolysis and opened thus a new way toward hemiketal structures which could also find interesting applications as less constrained scaffold.
      Graphical abstract image

      PubDate: 2016-01-27T19:32:04Z
       
  • 5'-spiro-cyclopropanated lactose derivatives as suitable intermediates for
           
    • Abstract: Publication date: Available online 25 January 2016
      Source:Carbohydrate Research
      Author(s): Venerando Pistarà, Antonio Rescifina, Antonino Corsaro
      A δ-dicarbonyl heptose has been prepared through an electrophilic ring opening procedure of a 5'-spirocyclopropanated lactose derivative. The reported synthetic procedure outlines a new route for the transformation of this renewable disaccharide into new and interesting δ-dicarbonyl sugars, synthetic precursors of cyclitols, carba- and azasugars. The experimental results of the cyclopropanation process, have been successful rationalized by in silico studies.
      Graphical abstract image

      PubDate: 2016-01-27T19:32:04Z
       
  • Editorial board
    • Abstract: Publication date: 8 February 2016
      Source:Carbohydrate Research, Volume 421




      PubDate: 2016-01-27T19:32:04Z
       
  • Graphical contents list
    • Abstract: Publication date: 8 February 2016
      Source:Carbohydrate Research, Volume 421




      PubDate: 2016-01-27T19:32:04Z
       
  • Influence of intramolecular hydrogen bonds on regioselectivity of
           glycosylation. Synthesis of lupane-type saponins bearing the OSW-1 saponin
           disaccharide unit and its isomers.
    • Abstract: Publication date: Available online 26 January 2016
      Source:Carbohydrate Research
      Author(s): Kinga Kuczynska, Piotr Cmoch, Lucie Rárová, Jana Oklešťková, Anna Korda, Zbigniew Pakulski, Miroslav Strnad
      A series of lupane-type saponins bearing OSW-1 disaccharide unit as well as its regio- and stereoisomers were prepared and used for the structure-activity relationships (SAR) study. Unexpected preference for 1→4-linked regioisomers and an unusual inversion of the conformation of the sugar rings were noted. Cytotoxic activity of new lupane compounds was evaluated in vitro and revealed that some saponins exhibited an interesting bioactivity profile against human cancer cell lines. Influence of the protecting groups on the cytotoxicity was investigated. These results open the way to the synthesis of various lupane-type triterpene and saponin derivatives as potential anticancer compounds.


      PubDate: 2016-01-27T19:32:04Z
       
  • Synthesis of type 2 lewis antigens via novel regioselective glycosylation
           of an orthogonally protected lactosamine diol derivative
    • Abstract: Publication date: Available online 19 January 2016
      Source:Carbohydrate Research
      Author(s): Yuji Yamazaki, Kyohei Sezukuri, Junko Takada, Hiroaki Obata, Shunsaku Kimura, Masashi Ohmae
      The novel and efficient synthesis of type 2 Lewis antigens is reported in this study. The rationally designed lactosamine-3,2′-diol derivative with an orthogonal set of protecting groups is efficiently glycosylated with a benzyl protected 1-thio-L-fucoside donor in a unique regioselective manner to produce Lewis x (Lex) and Lewis y (Ley) derivatives in good yields. These derivatives can be prepared not only exclusively but also synchronously by choosing the appropriate reaction temperature and donor-acceptor molar ratio. The Lex derivatives are easily converted into sulfated or non-sulfated Lex bearing a terminal azido functionalized oligo-(ethyleneoxide) linker; the Ley derivative having the same linker can also be prepared, all of which can be further used for the chemical modification of other compounds and materials.
      Graphical abstract image

      PubDate: 2016-01-22T09:27:26Z
       
  • Influence of the configurational pattern of sp2-iminosugar pseudo N-, S-,
           O- and C-glycosides on their glycoside inhibitory and antitumor properties
           
    • Abstract: Publication date: Available online 21 January 2016
      Source:Carbohydrate Research
      Author(s): Elena M. Sánchez-Fernández, Rita Gonçalves-Pereira, Rocío Rísquez-Cuadro, Gabriela B. Plata, José M. Padrón, José M. García Fernández, Carmen Ortiz Mellet
      The synthesis of a complete series of cyclic carbamate-type sp2-iminosugar N-, S-, O- and C-octyl pseudoglycosides related to nojirimycin, mannojirimycin and galactonojirimycin, all having the α-pseudoanomeric configuration, is reported. The gem-diamine-type N-pseudoglycosides can be accessed directly from the corresponding reducing sp2-imisosugar precursors by reaction with octylamine in methanol, whereas per-O-acetyl or 1-fluoro derivatives were used as pseudoglycosyl donors for the preparation of S-pseudoglycosides or O- and C-pseudoglycosides, respectively. Evaluation of their inhibitory properties against a panel of glycosidases evidenced selectivity profiles that strongly depend on the configurational pattern and the nature of the glycosidic linkage. On the contrary, the antiproliferative activity determined against a panel of tumor cell lines was largely independent of the relative orientation of the hydroxyl groups in the sp2-iminosugar moiety. Indeed, sp2-iminosugar representatives exhibiting significant growth inhibition potencies were identified in all three configurationally different types of compounds studied, namely α-d-gluco, α-d-manno and α-d-galacto glycoside analogues. Interestingly, none of the compounds affected viability and mortality of normal cells at the used concentrations. Altogether, the results strongly suggest that the anticancer activity of amphiphilic sp2-iminosugar glycosides might be unrelated, or not solely related, to their glycosidase inhibitory activity.
      Graphical abstract image

      PubDate: 2016-01-22T09:27:26Z
       
  • Evaluation of monovalent and multivalent iminosugars to modulate candida
           albicans β-1,2-mannosyltransferase activities
    • Abstract: Publication date: Available online 22 January 2016
      Source:Carbohydrate Research
      Author(s): Thomas Hurtaux, Ghenima Sfihi-Loualia, Yoan Brissonnet, Julie Bouckaert, Jean-Maurice Mallet, Boualem Sendid, Florence Delplace, Emeline Fabre, Sébastien G. Gouin, Yann Guérardel
      β-1,2-linked oligomannosides substitute the cell wall of numerous yeast species. Several of those including Candida albicans may cause severe infections associated with high rates of morbidity and mortality, especially in immunocompromised patients. β-1,2-mannosides are known to be involved in the pathogenic process and to elicit an immune response from the host. In C. albicans, the synthesis of β-mannosides is under the control of a family of nine genes coding for putative β-mannosyltransferases. Two of them, CaBmt1 and CaBmt3, have been shown to initiate and prime the elongation of the β-mannosides on the cell-wall mannan core. In the present study, we have assessed the modulating activities of monovalent and multivalent iminosugar analogues on these enzymes in order to control the enzymatic bio-synthesis of β-mannosides. We have identified a monovalent deoxynojirimycin (DNJ) derivative that inhibits the CaBmt1-catalized initiating activity, and mono-, tetra- and polyvalent deoxymannojirimycin (DMJ) that modulate the CaBmt1 activity toward the formation of a single major product. Analysis of the aggregating properties of the multivalent iminosugars showed their ability to elicit clusterization of both CaBmt1 and CaBmt3, without affecting their activity. These results suggest promising roles for multivalent iminosugars as controlling agents for the biosynthesis of β-1,2 mannosides and for monovalent DNJ derivative as a first target for the design of future β-mannosyltransferase inhibitors.
      Graphical abstract image

      PubDate: 2016-01-22T09:27:26Z
       
  • Comparison of the simulations of cellulosic crystals with three
           carbohydrate force fields
    • Abstract: Publication date: Available online 11 January 2016
      Source:Carbohydrate Research
      Author(s): Hitomi Miyamoto, Udo Schnupf, Michael Crowley, John W. Brady
      Three independently developed molecular mechanics force fields for carbohydrates have been used to simulate a suite of small molecule analogs of cellulose for which crystal structures have been reported, as a test to determine which might be best for simulations of cellulose itself. Such evaluation is necessary since the reported cellulose crystal structure is not stable in molecular dynamics simulations with any available force field. The present simulations found that all three resulted in small deviations from the reported crystal structures, but that all were reasonably accurate and none was clearly superior to the others for the entire suite of structures examined.
      Graphical abstract image

      PubDate: 2016-01-13T21:20:14Z
       
  • Structure and gene cluster of the O-antigen of Escherichia coli O137
    • Abstract: Publication date: Available online 11 January 2016
      Source:Carbohydrate Research
      Author(s): Andrei V. Perepelov, Xi Guo, Sof'ya N. Senchenkova, Yayue Li, Alexander S. Shashkov, Bin Liu, Yuriy A. Knirel
      The O-polysaccharide (O-antigen) was isolated from the lipopolysaccharide of Escherichia coli O137 and studied by sugar analysis and NMR spectroscopy. The following structure of the branched tetrasaccharide repeating unit was established: Both structure and gene cluster of the E. coli O137 polysaccharide are related to those of the E. coli K40 polysaccharide (Amor PA, Yethon JA, Monteiro MA, Whitfield C. J Bacteriol 1999;181:772-80), which lacks the side-chain glucosylation but contains serine that is amide-linked to GlcA. Functions of genes in the O137-antigen gene cluster were assigned by a comparison with those in K40 and sequences in the available databases. Particularly, predicted glycosyltransferases encoded in the gene cluster were assigned to the formation of three glycosidic linkages in the O-polysaccharide repeating unit.
      Graphical abstract image

      PubDate: 2016-01-13T21:20:14Z
       
  • Preparation of a squaraine-bounded cellulose derivative for photocurrent
           generation system
    • Abstract: Publication date: Available online 6 January 2016
      Source:Carbohydrate Research
      Author(s): Yasuko Saito, Hiroshi Kamitakahara, Toshiyuki Takano
      A regio-selectively squaraine (SQ)-bounded cellulose derivative (4) with a degree of substitution of SQ (DSSQ) of 0.55 was prepared from 6-O-(4-methoxytrityl) cellulose (1) by three reaction steps in 77% total yield. Lauryl SQ carboxylate (8) was also prepared as a reference sample. The photostability of SQ moieties of compound 4 in CHCl3 was not improved when compared with SQ-COOH (7), but that of SQ moiety of compound 8 was improved unexpectedly. The Langmuir-Blodgett monolayer films 4B and 8B on an indium tin oxide (ITO) electrode were successfully prepared from compounds 4 and 8 by a vertical dipping method, respectively. The films 4B and 8B showed photocurrent generation performances in the region of 550-680 nm. The quantum yields at 650 nm of film 4B was higher than that of film 8B. These results showed that the cellulose backbone of compound 4 acts as an effective scaffold for the good photocurrent generation performances and that compound 4 was a promising complementary material of the porphyrin-bounded cellulose derivatives (for photocurrent generation at 400-420 nm) for effective utilization of solar light, as well as the phthalocyanine-bounded cellulose derivatives (for photocurrent generation at 650-720 nm).
      Graphical abstract image

      PubDate: 2016-01-09T21:16:34Z
       
  • Preparation of s-glycoside surfactants and cysteine thioglycosides using
           minimally competent lewis acid catalysis
    • Abstract: Publication date: Available online 6 January 2016
      Source:Carbohydrate Research
      Author(s): Lajos Z. Szabó, Dillon J. Hanrahanv, Evan M. Jones, Erin Martin, Jeanne E. Pemberton, Robin Polt
      Here we report a method for the preparation of anomerically pure β-S-glycopyranosides (1,2-trans-glycosides) from the corresponding peracetate donors. S-glycosylation was performed in CHCl3 at reflux in the presence of a catalytic amount of InBr3. Deacylation of the intermediate peracetates were achieved under Zemplén conditions. Five pyranose examples, monosaccharides D-glucose and D-galactose and disaccharides cellobiose, maltose, and lactose, were used as donors, and five thiols including an α/ω dithiol and Fmoc-L-cysteine were used as acceptors. Melting points, high res MS, [α]D and NMR data (1H and 13C, including COSY, HSQC and HMBC) are reported for compounds not previously described.
      Graphical abstract image

      PubDate: 2016-01-09T21:16:34Z
       
  • Editorial board
    • Abstract: Publication date: February 2016
      Source:Carbohydrate Research, Volume 420




      PubDate: 2016-01-09T21:16:34Z
       
  • Graphical contents list
    • Abstract: Publication date: February 2016
      Source:Carbohydrate Research, Volume 420




      PubDate: 2016-01-09T21:16:34Z
       
  • Isolation of sophorose during sophorolipid production and studies of its
           stability in aqueous alkali: epimerization of sophorose to
           2-o-β-d-glucopyranosyl-d-mannose
    • Abstract: Publication date: Available online 7 January 2016
      Source:Carbohydrate Research
      Author(s): Ammar AL-Jasim, Mark Davis, Douglas Cossar, Timothy Miller, Paul Humphreys, Andrew P. Laws
      NMR and anion exchange chromatography analysis of the waste streams generated during the commercial production of sophorolipids by the yeast Candida bombicola identified the presence of small but significant quantities (1 % w/v) of free sophorose. Sophorose, a valuable disaccharide, was isolated from the aqueous wastes using a simple extraction procedure and was purified by chromatography on a carbon celite column providing easy access to large quantities of the disaccharide. Experiments were undertaken to identify the origin of sophorose and it is likely that acetylated sophorose derivatives were produced by an enzyme catalysed hydrolysis of the glucosyl-lipid bond of sophorolipids; the acetylated sophorose derivatives then undergo hydrolysis to release the parent disaccharide. Treatment of sophorose with aqueous alkali at elevated temperatures (0.1M NaOH at 50 OC) resulted in C2-epimerisation of the terminal reducing sugar and its conversion to the corresponding 2-O-β-D-glucopyranosyl-D-mannose which was isolated and characterised. In aqueous alkaline solution β-(1,2)-linked glycosidic bonds do not undergo either hydrolysis or peeling reactions.
      Graphical abstract image

      PubDate: 2016-01-09T21:16:34Z
       
  • Synthesis and evaluation of a series of 6-chloro-4-methylumbelliferyl
           glycosides as fluorogenic reagents for screening metagenomic libraries for
           glycosidase activity
    • Abstract: Publication date: Available online 5 January 2016
      Source:Carbohydrate Research
      Author(s): Hong-Ming Chen, Zachary Armstrong, Steven J Hallam, Stephen G Withers
      Screening of large enzyme libraries such as those derived from metagenomic sources requires sensitive substrates. Fluorogenic glycosides typically offer the best sensitivity but typically must be used in a stopped format to generate good signal. Use of fluorescent phenols of pKa < 7, such as halogenated coumarins, allows direct screening at neutral pH. The synthesis and characterisation of a set of nine different glycosides of 6-chloro-4-methylumbelliferone are described. The use of these substrates in a pooled format for screening of expressed metagenomic libraries yielded a “hit rate” of 1 in 60. Hits were then readily deconvoluted with the individual substrates in a single plate to identify specific activities within each clone. The use of such a collection of substrates greatly accelerates the screening process.


      PubDate: 2016-01-05T21:07:36Z
       
  • Synthesis of 5-O-oligoglucosyl extended α-(2→4)-Kdo
           disaccharides corresponding to inner core fragments of Moraxellaceae
           lipopolysaccharides
    • Abstract: Publication date: Available online 5 January 2016
      Source:Carbohydrate Research
      Author(s): Barbara Pokorny, Paul Kosma
      The heptose-deficient inner core of the lipopolysaccharide of several pathogenic strains of the Moraxellaceae family (Moraxella, Acinetobacter) and of Bartonella henselae, respectively, comprises an α-D-glucopyranose attached to position 5 of Kdo. In continuation of the synthesis of fragments of Acinetobacter haemolyticus LPS, the branched α-Glcp-(1→5)[α-Kdo-(2→4)]-α-Kdo trisaccharide motif was elaborated. The glycosylation of a suitably protected, α-(2→4)-interlinked Kdo-disaccharide was achieved in high yield and fair anomeric selectivity using a 4,6-O-benzylidene N-phenyltrifluoroacetimidate glucosyl donor. Subsequent regioselective reductive benzylidene opening afforded a trisaccharide acceptor, which was extended with β-D-glucopyranosyl and isomaltosyl residues. Global deprotection provided tri- to pentasaccharide structures corresponding to the inner core region of A. haemolyticus lipopolysaccharide.
      Graphical abstract image

      PubDate: 2016-01-05T21:07:36Z
       
  • Sugar-based novel chiral macrocycles for inclusion applications and chiral
           recognition
    • Abstract: Publication date: Available online 23 December 2015
      Source:Carbohydrate Research
      Author(s): Ankita Singh, Vinod Khatri, Shashwat Malhotra, Ashok K. Prasad
      A convergent template assisted synthesis of sugar-based chiral macrocycles has been achieved. The host-guest inclusion studies have revealed significant interactions of the synthesized macrocycle with primary over secondary ammonium salt. The chiral macrocyle also discriminates between D- and L-phenylalanine methyl ester hydrochlorides as revealed by 1H NMR spectral studies on the mixture of the host and the guest molecules.
      Graphical abstract image

      PubDate: 2015-12-25T12:40:16Z
       
  • Teichoic, teichulosonic and teichuronic acids in thе cell wall of
           Brevibacterium aurantiacum VKM Ac-2111Т
    • Abstract: Publication date: Available online 23 December 2015
      Source:Carbohydrate Research
      Author(s): Alexander S. Shashkov, Natalia V. Potekhina, Sofya N. Senchenkova, Lyudmila I. Evtushenko
      Two different teichoic acids, along with a teichulosonic and a teichuronic acids, were identifined in thе cell wall of Brevibacterium aurantiacum VKM Ac-2111Т. One teichoic acid is 1,3-poly(glycerol phosphate) with 2-acetamido-2-deoxy-α-d-galactopyranose and l-glutamic acid as non-stoichiometric substituents at O-2 of the glycerol residue. The second one is a poly(glycosylglycerol phosphate) with -4)-α-D-Galp-(1→2)-sn-Gro-(3-P- and/or -6)-α-D-Galp-(1→2)-sn-Gro-(3-P- units in the main chain. The structure of the first has not been reported so far, while the latter one is new for actinobacteria. The teichulosonic acid with α-3-deoxy-β-d-glycero-d-galacto-non-2-ulopyranosonic acid (Kdn) and β-D-glucopyranose residues in the backbone represents a novel polymer: →8)-α-Kdn-(2→6)-β-D-Glcp-(1→. The teichuronic acid has also hitherto unknown structure: →3)-β-D-Galf(2OAc)0.3-(1→3)-β-D-GlcpА-(1→ and is found in members of the genus Brevibacterium for the first time. The polymer structures were elucidated using 1D- and 2D-NMR spectroscopy: 1H,1H COSY, TOCSY, ROESY, 1H,13C HSQC, HSQC-TOCSY, and 1H,13C and 1H,31P HMBC.


      PubDate: 2015-12-25T12:40:16Z
       
  • C-Glucopyranosyl-1,2,4-triazol-5-ones: synthesis and inhibition of
           glycogen phosphorylase
    • Abstract: Publication date: Available online 24 December 2015
      Source:Carbohydrate Research
      Author(s): Éva Bokor, Zsolt Széles, Tibor Docsa, Pál Gergely, László Somsák
      Various C-glucopyranosyl-1,2,4-triazolones were designed as potential inhibitors of glycogen phosphorylase. Syntheses of these compounds were performed with O-perbenzoylated glucose derivatives as precursors. High temperature ring closure of N1 -carbamoyl-C-β-D-glucopyranosyl formamidrazone gave 3-β-D-glucopyranosyl-1,2,4-triazol-5-one. Reaction of N1 -tosyl-C-β-D-glucopyranosyl formamidrazone with ClCOOEt furnished 3-β-D-glucopyranosyl-1-tosyl-1,2,4-triazol-5-one. In situ prepared β-D-glucopyranosylcarbonyl isocyanate was transformed by PhNHNHBoc into 3-β-D-glucopyranosyl-1-phenyl-1,2,4-triazol-5-one, while the analogous 1-(2-naphthyl) derivative was obtained from the unsubstituted triazolone by naphthalene-2-boronic acid in a Cu(II) catalyzed N-arylation. Test compounds were prepared by Zemplén deacylation. The new glucose derivatives had weak or no inhibition of rabbit muscle glycogen phosphorylase b: the best inhibitor was 3-β-D-glucopyranosyl-1-(2-naphthyl)-1,2,4-triazol-5-one (Ki = 80 µM).
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      PubDate: 2015-12-25T12:40:16Z
       
  • Editorial board
    • Abstract: Publication date: January 2016
      Source:Carbohydrate Research, Volume 419




      PubDate: 2015-12-25T12:40:16Z
       
  • Graphical contents list
    • Abstract: Publication date: January 2016
      Source:Carbohydrate Research, Volume 419




      PubDate: 2015-12-25T12:40:16Z
       
  • Corrigendum to “1H NMR analysis of the
           lactose/β-galactosidase-derived galacto-oligosaccharide components of
           Vivinal® GOS up to DP5” [Carbohydr. Res. 400 (2014)
           59–73]
    • Abstract: Publication date: January 2016
      Source:Carbohydrate Research, Volume 419
      Author(s): Sander S. van Leeuwen, Bas J.H. Kuipers, Lubbert Dijkhuizen, Johannis P. Kamerling



      PubDate: 2015-12-25T12:40:16Z
       
  • Identification and characterisation of a biosynthetic locus for moraxella
           bovis lipo-oligosaccharide
    • Abstract: Publication date: Available online 15 December 2015
      Source:Carbohydrate Research
      Author(s): Isabelle Faglin, I. Darren Grice, S.R.A.M. Eranda Ratnayake, Terese-Marie Daal, Sanjesh Singh, Jennifer C. Wilson, Ian R. Peak
      Moraxella bovis is a Gram-negative gammaproteobacterium and is one of the causative agents of infectious bovine keratoconjunctivitis. The structure of lipooligosaccharide (LOS) from strain Epp63 was recently elucidated. In the present study a genetic locus of seven genes encoding genes with high similarity to glycosyltransferases has been identified. Mutation of these putative glycosyltransferase genes resulted in M. bovis mutant bacteria that expressed truncated LOS structures. The structures of the oligosaccharide (OS) expressed by the mutant strains were elucidated and demonstrated the role of the glycosyltransferase enzymes in the LOS biosynthesis of M. bovis. The glycosyltransferase genes designated lgt1, lgt3, and lgt6 are highly similar to the genes in the related bacterium M. catarrhalis. In addition, there are syntenic similarities with the corresponding LOS biosynthesis locus in M. catarrhalis and other members of Moraxellaceae.
      Graphical abstract image

      PubDate: 2015-12-17T12:33:19Z
       
  • Synthesis of a 2-n,n-dibenzylamino glucopyranosyl trichloroacetimidate
           glycosyl donor and evaluation of its utility in stereoselective
           glycosylation
    • Abstract: Publication date: Available online 9 December 2015
      Source:Carbohydrate Research
      Author(s): Stacy P. Ali, Nigel Kevin Jalsa
      The 2-N,N-dibenzylamino glucopyranosyl trichloroacetimidate donor was synthesized and an extensive investigation of its glycosyl donor properties was conducted. Coupling studies incorporated a variety of glycosyl promoters and a range of acceptor alcohols representing different reactivities and protecting group patterns. Various reaction temperatures, solvents and glycosylation protocols were also examined. Exclusive β-stereoselectivity was obtained in moderate to good yields with eight novel glycosides being produced, by probable neighbouring group participation via the formation of an aziridinium ion intermediate. Plausible reaction mechanisms were proposed based on the results obtained.
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      PubDate: 2015-12-13T10:00:22Z
       
  • 5-fluoro derivatives of 4-epi-isofagomine as d-galactosidase inhibitors
           and potential pharmacological chaperones for GM1-gangliosidosis as well as
           fabry's disease
    • Abstract: Publication date: Available online 8 December 2015
      Source:Carbohydrate Research
      Author(s): Martin Thonhofer, Andres Gonzalez Santana, Roland Fischer, Ana Torvisco Gomez, Robert Saf, Michael Schalli, Arnold E. Stütz, Stephen G. Withers
      Electrophilic fluorination of an exocyclic methoxymethylene enol ether derived from N-tert-butyloxycarbonyl-1,5-dideoxy-1,5-imino-3,4-O-isopropylidene-D-erythro-pent-2-ulose (11) provided the 5-fluoro derivative of the powerful β-galactosidase inhibitor 4-epi-isofagomine (8). This structural alteration, in combination with N-alkylation, led to considerably improved α-galactosidase selectivity. New compounds may serve as leads en route to new pharmacological chaperones for Fabry's disease.
      Graphical abstract image

      PubDate: 2015-12-13T10:00:22Z
       
  • Reactivity of cellulose reducing end in pyrolysis as studied by methyl
           glucoside-impregnation
    • Abstract: Publication date: Available online 7 December 2015
      Source:Carbohydrate Research
      Author(s): Seiji Matsuoka, Haruo Kawamoto, Shiro Saka
      For better understanding of the roles of cellulose reducing ends during thermal degradation of cellulose and wood, cellulose samples impregnated with methyl-β-D-glucopyranoside (GlcβOMe), a simple non-reducing sugar model, were pyrolyzed under N2 at relatively low temperatures of 200-280°C. By the impregnation, cellulose was rather stabilized against discoloration and weight-loss through converting the reducing ends into the glycosides with GlcβOMe. Alternatively, polymerization and discoloration of GlcβOMe were accelerated in the presence of cellulose. A mechanism via reducing sugars as reactive intermediates formed through hydrolysis is proposed to explain these phenomena. These informations would be useful to understand the interactions between cellulose and hemicellulose in wood cell wall as well as the role of the reducing ends in cellulose thermal degradation.
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      PubDate: 2015-12-09T09:54:50Z
       
  • Synthesis and biological evaluation of novel dioxa-bicycle c-aryl
           glucosides as SGLT2 inhibitors
    • Abstract: Publication date: Available online 7 December 2015
      Source:Carbohydrate Research
      Author(s): Qi Yan, Ning Ding, Yingxia Li
      A series of novel C-aryl glucosides containing dioxa-bicycle were synthesized and evaluated for inhibition activity against hSGLT2. Among the compounds tested, compound 6a showed moderate SGLT2 inhibition activities at 700 nM. The results could benefit the discovery of new SGLT2 inhibitors.
      Graphical abstract image

      PubDate: 2015-12-09T09:54:50Z
       
  • Immune sensing of microbial glycolipids and related conjugates by t cells
           and the pattern recognition receptors MCL and mincle
    • Abstract: Publication date: Available online 8 December 2015
      Source:Carbohydrate Research
      Author(s): Dylan G.M. Smith, Spencer J. Williams
      Microbes produce a wide range of small molecule glycoconjugates that constitute unique molecular signatures. These molecules are recognized by a range of detection systems, triggering immune responses to microbial pathogens and commensals. The antigen-presenting molecules of the CD1 class, CD1a-d, capture lipidic molecules and present them to diverse and innate-like T cell populations including natural killer T cells and germline-encoded mycolyl reactive T cells. The antigen-presenting molecule MR1 captures vitamin B metabolites and presents them to mucosal associated invariant T cells. In both cases recognition of the small molecule-antigen presenting molecule complexes occurs through T cell receptors on the surface of T lymphocytes. The pattern recognition receptors macrophage C-type lectin (MCL) and macrophage inducible C-type lectin (Mincle) receptors sense glycolipids and through signalling initiate cellular activation, shaping immune responses to peptide antigens, including the differentiation of naïve T cells into conventional effector T helper cells. In this review we provide an overview of the diverse structures of immunogenic lipidic molecules and vitamin B metabolites and their recognition by select systems of the immune system. Future advances in our understanding of the roles of such molecules in innate and adaptive immune responses will require the coordinated efforts of synthetic and natural products chemists, immunologists and biologists.
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      PubDate: 2015-12-09T09:54:50Z
       
  • Ingasaponin, a complex triterpenoid saponin with immunological adjuvant
           activity from inga laurina
    • Abstract: Publication date: Available online 8 December 2015
      Source:Carbohydrate Research
      Author(s): Maria de Fátima Simão Jucá Cruz, Gabriela Moysés Pereira, Marcela Gonçalves Ribeiro, Ari Miranda da Silva, Luzineide Wanderley Tinoco, Bernadete Pereira da Silva, José Paz Parente
      As part of our search of bioactive saponins from Brazilian plants, phytochemical study of the seeds of Inga laurina led to the isolation of a new complex triterpenoid saponin, named ingasaponin. It is the first saponin isolated from a species of Inga genus. It was isolated by using chromatographic methods and its structural elucidation was performed using detailed analyses of 1H and 13C NMR spectra including 2D-NMR spectroscopic techniques and chemical conversions. Its structure was established as 21-[[(2E,6S)-6-[[6-deoxy-4-O-[(2E,6S)-6-[(β-D-glucopyranosyl)oxy]-2,6-dimethyl-1-oxo-2,7-octadienyl]-[(β-D-glucopyranosyl)oxy]-2,6-dimethyl-1-oxo-2,7-octadienyl]-[(β-D-glucopyranosyl)oxy]-2,6-dimethyl-1-oxo-2,7-octadienyl]-[(β-D-glucopyranosyl)oxy]-2-(hydroxymethyl)-6-methyl-1-oxo-2,7-octadienyl]oxy]-16-hydroxy-3-[[O-β-D-xylopyranosyl-(1→2)-O-α-L-arabinopyranosyl-(1→6)-2-(acetylamino)-2-deoxy-β-D-glucopyranosyl]oxy]-(3β,16α,21β)-olean-12-en-28-oic acid O-α-L-arabinofuranosyl-(1→4)-O-[β-D-glucopyranosyl-(1→3)]-O-6-deoxy-α-L-mannopyranosyl-(1→2)-β-D-glucopyranosyl ester (1). The hemolytic potential of 1 was evaluated using in vitro assays, and its adjuvant activity on the cellular immune response against ovalbumin antigen was investigated using in vivo models.
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      PubDate: 2015-12-09T09:54:50Z
       
  • Editorial board
    • Abstract: Publication date: 11 December 2015
      Source:Carbohydrate Research, Volume 418




      PubDate: 2015-12-09T09:54:50Z
       
  • Graphical contents list
    • Abstract: Publication date: 11 December 2015
      Source:Carbohydrate Research, Volume 418




      PubDate: 2015-12-09T09:54:50Z
       
  • Characterization of a purified thermostable xylanase from caldicoprobacter
           algeriensis sp. nov. strain TH7C1T
    • Abstract: Publication date: Available online 1 December 2015
      Source:Carbohydrate Research
      Author(s): Amel Bouanane-Darenfed, Nawel Boucherba, Khelifa Bouacem, Mohammed Gagaoua, Manon Joseph, Salima Kebbouche-Gana, Farida Nateche, Hocine Hacene, Bernard Ollivier, Jean-Luc Cayol, Marie-Laure Fardeau
      The present study investigates the purification and biochemical characterization of an extracellular thermostable xylanase (called XYN35) from Caldicoprobacter algeriensis sp. nov., strain TH7C1T, a thermophilic, anaerobic strain isolated from the hydrothermal hot spring of Guelma (Algeria). The maximum xylanase activity recorded after 24 h of incubation at 70 °C and in an optimized medium containing 10 g/l mix birchwood- and oats spelt-xylan, was 250 U/ml. The pure protein was obtained after heat treatment (1 h at 70 °C), followed by sequential column chromatographies on Sephacryl S-200 gel filtration and Mono-S Sepharose anion-exchange. Matrix assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF/MS) analysis indicated that the purified enzyme is a monomer with a molecular mass of 35,075.10 Da. The results from amino-acid sequence analysis revealed high homology between the 21 NH2-terminal residues of XYN35 and those of bacterial xylanases. The enzyme showed optimum activity at pH 11 and 70 °C. While XYN35 was activated by Ca2+, Mn2+, and Mg2+, it was completely inhibited by Hg2+ and Cd2+. The xylanase showed higher specific activity on soluble oat-spelt xylan, followed by beechwood xylan. This enzyme was also noted to obey the Michaelis-Menten kinetics, with K m and k cat values on oat-spelt xylan being 1.33 mg/ml and 400 min-1, respectively. Thin-layer chromatography soluble oat-spelt xylan (TLC) analysis showed that the final hydrolyzed products of the enzyme from birchwood xylan were xylose, xylobiose, and xylotriose. Taken together, the results indicated that the XYN35 enzyme has a number of attractive biochemical properties that make it a potential promising candidate for future application in the pulp bleaching industry.
      Graphical abstract image

      PubDate: 2015-12-05T19:35:15Z
       
  • Comparison of celery (apium graveolens l.) collenchyma and parenchyma cell
           wall polysaccharides enabled by solid-state 13c NMR
    • Abstract: Publication date: Available online 4 December 2015
      Source:Carbohydrate Research
      Author(s): Zoran Zujovic, Da Chen, Laurence D. Melton
      Collenchyma cells with their thicken walls, are one of specific mechanical support tissues for plants while parenchyma cells are thin walled and serve multiple functions. The parenchyma tissue is what you enjoy eating while collenchyma, because of its fibrous nature is not so attractive. Celery is a useful model for comparing the cell walls (CWs) of the two cell types such as collenchyma and parenchyma. However, to date the structural characteristics of collenchyma and parenchyma cell walls from the same plant have not been compared. Monosaccharide composition suggested the collenchyma cell walls contained less pectin but more hemicellulose in comparison to parenchyma. High-resolution solid-state NMR spectra of highly mobile pectins revealed that the arabinan signals were more evident in the collenchyma spectrum while galactan showed a much stronger resonance in the parenchyma spectrum. In addition, methyl esterified and non-esterified galacturonic acid signal were observed in parenchyma CWs, but only latter one appeared in the collenchyma. The ratio of cellulose surface/interior obtained from CP/MAS spectra for collenchyma suggested the cellulose microfibrils were ~ 2.4 nm while in the parenchyma were somewhat larger. X-ray diffraction indicated the size of the cellulose microfibrils were the same for both types of CWs.
      Graphical abstract image

      PubDate: 2015-12-05T19:35:15Z
       
  • Structure and gene cluster of the O–antigen of escherichia coli o96
    • Abstract: Publication date: Available online 23 November 2015
      Source:Carbohydrate Research
      Author(s): Xi Guo, Sof'ya N. Senchenkova, Alexander S. Shashkov, Andrei V. Perepelov, Bin Liu, Yuriy A. Knirel
      Mild acid degradation of the lipopolysaccharide of Escherichia coli O96 aforded a mixture of two polysaccharides. The following structure of the pentasaccharide repeating unit of the major polymer was established by sugar analysis, Smith degradation, and 1H and 13C NMR spectroscopy: The O-antigen gene cluster of E. coli O96 between conserved galF and gnd genes was found to be consistent with this structure, and hence, the major polysaccharide represents the O96-antigen. The O96-antigen structure and gene cluster are similar to those of E. coli O170, and two proteins encoded in the gene clusters of both bacteria were putatively assigned a function of galactofuranosyltransferases. The minor polymer has the same structure as a peptidoglycan-related polysaccharide reported earlier in Providencia alcalifeciens O45 and several other O-serogoups of this species (Ovchinnikova OG, Liu B, Kocharova NA, Shashkov AS, Kondakova AN, Siwinska M, Feng L, Rozalski A, Wang L, Knirel YA. Biochemistry (Moscow) 2012;77:609-15): →4)-β-d-GlcpNAc-(1→4)-β-d-GlcpNAc3(Rlac-lAla)-(1→ where Rlac-lAla indicates (R)-1-[(S)-1-carboxyethylaminocarbonyl]ethyl.
      Graphical abstract image

      PubDate: 2015-11-26T19:22:14Z
       
  • Physicochemical properties of thermotolerant extracellular
           β-glucosidase from talaromyces thermophilus and enzymatic synthesis
           of cello-oligosaccharides.
    • Abstract: Publication date: Available online 14 November 2015
      Source:Carbohydrate Research
      Author(s): Hanen Mallek-Fakhfakh, Hafedh Belghith
      A thermophilic fungus, Talaromyces thermophilus that produces a novel thermotolerant extra-cellular β-glucosidase (Bgl.tls) was isolated from Tunisian soil samples. The enzyme was purified from the culture filtrates of Talaromyces thermophilus grown on lactose using gel filtration, ion exchange chromatography and FPLC. The monomeric enzyme had a molecular mass of 116.0 kDa and a high specific activity of 1429 UI/mg. Bgl.tls exhibited optimal activity at pH 5.0 and 65°C. It was also stable over a wide range of pH (4.0 – 10.0) and stable at 50°C for 34 h. Bgl.tls retained about 80% of its initial activity after 1.0 hours of preincubation at 60 °C. The Km and Vmax values recorded for pNPG were 0.25 mM and 228.7 µmol min-1, respectively. Bgl.tls was activated by Mn2+, Mg2+, Ca2+ and Co2+ but obviously inhibited by Fe2+ and Cu2+. It was able to hydrolyze a variety of aryl / alkyl -β-glucosides and disaccharides as well as (1→6) and (1→4)-β-glucosidic linkages and α-glycosidic substrates, thus providing evidence for its broad substrate specificity. The enzyme also displayed high hydrolytic and transglycosylation activities. Overall, this study is the first report on the purification and physicochemical properties of a β-glucosidase secreted by T. thermophilus. The cello-oligosaccharides synthesized by this enzyme within 2 h were mainly cellotriose, cellotetraose and cellopentaose identified by HPLC and ESI-MS techniques.
      Graphical abstract image

      PubDate: 2015-11-19T09:19:30Z
       
  • Mechanism-based candidate inhibitors of uridine diphosphate
           galactopyranose mutase (UGM)
    • Abstract: Publication date: January 2016
      Source:Carbohydrate Research, Volume 419
      Author(s): Yasaman Mahdavi-Amiri, Sankar Mohan, Silvia Borrelli, Kathryn Slowski, David A.R. Sanders, B. Mario Pinto
      Uridine diphosphate-galactopyranose mutase (UGM), an enzyme found in many eukaryotic and prokaryotic human pathogens, catalyzes the interconversion of UDP-galactopyranose (UDP-Galp) and UDP-galactofuranose (UDP-Galf), the latter being used as the biosynthetic precursor of the galactofuranose polymer portion of the mycobacterium cell wall. We report here the synthesis of a sulfonium and selenonium ion with an appended polyhydroxylated side chain. These compounds were designed as transition state mimics of the UGM-catalyzed reaction, where the head groups carrying a permanent positive charge were designed to mimic both the shape and positive charge of the proposed galactopyranosyl cation-like transition state. An HPLC-based UGM inhibition assay indicated that the compounds inhibited about 25% of UGM activity at 500 µM concentration.
      Graphical abstract image

      PubDate: 2015-11-19T09:19:30Z
       
  • The preliminary study of immune superparamagnetic iron oxide nanoparticles
           for the detection of lung cancer in magnetic resonance imaging
    • Abstract: Publication date: Available online 12 November 2015
      Source:Carbohydrate Research
      Author(s): Xinyuan Wan, Yuanqing Song, Nijia Song, Jiehua Li, Lie Yang, Yuan Li, Hong Tan
      To improve the sensitive and specific detection of metastasis of lung cancer, this study fabricated immune superparamagnetic iron oxide nanoparticles (SPIONs) used in magnetic resonance (MR) immumoimaging. These SPIONs were coated with oleic acid and carboxymethyl dextran, and then conjugated to mouse anti-CD44v6 monoclonal antibody. The physicochemical properties of magnetic nanoparticles without monoclonal antibody were characterized by X-ray powder diffraction (XRD), thermogravimetric analysis (TGA), and Fourier transform infrared spectroscopy (FTIR). The sizes of the nanoparticles were determined by dynamic light scattering measurements (DLS) and transmission electron microscope (TEM). Coated nanoparticles could well disperse in water with low dosage of CMD as the Fe/CMD ratio is 1/1 and 2/1 (w/w). Importantly, these SPIONs have relatively high saturation magnetization, as measured by vibrating sample magnetometer (VSM). They could efficiently become the transversal relaxation times (T2) contrast agent to improve detection limit through measured in vitro magnetic resonance imaging (MRI) and actively target to Human lung adenocarcinoma (A549) cells in vitro cell culture. Thus, these immune SPIONs are potentially useful for lung tumor-targeting diagnosis.
      Graphical abstract image

      PubDate: 2015-11-15T11:22:16Z
       
  • Novel structural features of the immunocompetent ceramide phospho-inositol
           glycan core from trichomonas vaginalis
    • Abstract: Publication date: Available online 10 November 2015
      Source:Carbohydrate Research
      Author(s): Christian Heiss, Zhirui Wang, Ian Black, Parastoo Azadi, Raina N. Fichorova, Bibhuti N. Singh
      The ceramide phosphoinositol glycan core (CPI-GC) of the lipophosphoglycan of Trichomonas vaginalis is a major virulent factor of this common genitourinary parasite. While its carbohydrate composition has been reported before, its structure has remained largely unknown. We isolated the glycan portions of CPI-GC by nitrous acid deamination and hydrofluoric acid treatment and investigated their structures by methylation analysis and 1- and 2-D NMR. We found that the α-anomer of galactose is a major constituent of CPI-GC. The β-anomer was found exclusively at the non-reducing end of CPI-GC side chains. Furthermore the data showed that the rhamnan backbone is more complex than previously thought and that the inositol residue at the reducing end is linked to a 4-linked α-glucuronic acid (GlcA) residue. This appears to be the most striking and novel feature of this GPI-anchor type molecule.
      Graphical abstract image

      PubDate: 2015-11-11T13:26:51Z
       
  • Alternative synthesis and antibacterial evaluation of
           1,5-dideoxy-1,5-imino-l-rhamnitol
    • Abstract: Publication date: Available online 4 November 2015
      Source:Carbohydrate Research
      Author(s): Suresh Dharuman, Yichen Wang, David Crich
      A convenient synthesis is described of 5-azido-5-deoxy-2,3-O-isopropylidene-L-rhamnofuranose from L-rhamnose in seven steps and 17% overall yield. A key feature of the synthesis is the selective oxidation of the secondary alcohol in 2,3-O-isopropylidene-L-rhamnofuranose in the presence of the hemiacetal to give the corresponding ketone in good yield using the Parikh-Doering reagent. 5-Azido-5-deoxy-2,3-O-isopropylidene-L-rhamnofuranose is then converted by a literature protocol to 1,5-dideoxy-1,5-imino-L-rhamnitol, which was found to have no significant antimicrobial activity against Pseudomonas aeruginosa, methicillin-resistant Staphylococcus aureus, and Escherichia coli.
      Graphical abstract image

      PubDate: 2015-11-07T13:24:43Z
       
  • Characterizing non-hydrolyzing neisseria meningitidis serogroup a
           UDP-n-acetylglucosamine (UDP-GlcNAc) 2-epimerase using
           UDP-n-acetylmannosamine (UDP-ManNAc) and derivatives
    • Abstract: Publication date: Available online 5 November 2015
      Source:Carbohydrate Research
      Author(s): Lei Zhang, Musleh M. Muthana, Hai Yu, John B. McArthur, Jingyao Qu, Xi Chen
      Neisseria meningitidis serogroup A non-hydrolyzing uridine 5'-diphosphate-N-acetylglucosamine (UDP-GlcNAc) 2-epimerase (NmSacA) catalyzes the interconversion between UDP-GlcNAc and uridine 5'-diphosphate-N-acetylmannosamine (UDP-ManNAc). It is a key enzyme involved in the biosynthesis of the capsular polysaccharide [-6ManNAcα1-phosphate-]n of Neisseria meningitidis serogroup A, one of the six serogroups (A, B, C, W-135, X, and Y) that account for most cases of Neisseria meningitidis-caused bacterial septicemia and meningitis. Neisseria meningitidis serogroup A is responsible for large epidemics in the developing world, especially in Africa. Here we report that UDP-ManNAc could be used as a substrate for C-terminal His6-tagged recombinant NmSacA (NmSacA-His6) in the absence of UDP-GlcNAc. NmSacA-His6 was activated by UDP-GlcNAc and inhibited by 2-acetamidoglucal and UDP. Substrate specificity study showed that NmSacA-His6 could tolerate several chemoenzymatically synthesized UDP-ManNAc derivatives as substrates although its activity was much lower than non-modified UDP-ManNAc. Homology modeling and molecular docking revealed likely structural determinants of NmSacA substrate specificity. This is the first detailed study of Neisseria meningitidis serogroup A UDP-GlcNAc 2-epimerase.
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      PubDate: 2015-11-07T13:24:43Z
       
  • Synthesis of 3-aminopropyl glycosides of linear
           β-(1→3)-d-glucooligosaccharides
    • Abstract: Publication date: Available online 30 October 2015
      Source:Carbohydrate Research
      Author(s): Dmitry V. Yashunsky, Yury E. Tsvetkov, Alexey A. Grachev, Alexander O. Chizhov, Nikolay E. Nifantiev
      3-Aminopropyl glycosides of a series of linear β-(1→3)-linked d-glucooligosaccharides containing from 3 to 13 monosaccharide units were efficiently prepared. The synthetic scheme featured highly regioselective glycosylation of 4,6-O-benzylidene-protected 2,3-diol glycosyl acceptors with a disaccharide thioglycoside donor bearing chloroacetyl groups at O-2′ and -3′ as a temporary protection of the diol system. Iteration of the deprotection and glycosylation steps afforded the series of the title oligoglucosides differing in length by two monosaccharide units. A novel procedure for selective removal of acetyl groups in the presence of benzoyl ones consisting in a brief treatment with a large excess of hydrazine hydrate has been proposed.
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      PubDate: 2015-11-03T08:51:52Z
       
  • Expanded acceptor substrates flexibility study of flavonol
           7-O-rhamnosyltransferase, AtUGT89C1 from Arabidopsis thaliana
    • Abstract: Publication date: 11 December 2015
      Source:Carbohydrate Research, Volume 418
      Author(s): Prakash Parajuli, Ramesh Prasad Pandey, Nguyen Thi Huyen Trang, Tae Jin Oh, Jae Kyung Sohng
      Acceptor substrates flexibility of previously characterized flavonol 7-O-rhamnosyltransferase (AtUGT89C1) from Arabidopsis thaliana was explored with an endogenous nucleotide diphosphate sugar and five different classes of flavonoids (flavonols, flavones, flavanones, chalcone and stilbenes) through a biotransformation approach. In contrast to the previous reports, this study highlights the expanded acceptor substrate promiscuity of AtUGT89C1 for the regiospecific glycosylation of diverse class of flavonoids at 7-hydroxyl position using microbial thymidine diphosphate (TDP)-l-rhamnose as sugar donor instead of uridine diphosphate-l-rhamnose. We examine the biocatalytic potential of AtUGT89C1 using endogenous sugar (TDP-l-rhamnose) from E. coli to generate a library of flavonoid 7-O-rhamnosides.
      Graphical abstract image

      PubDate: 2015-10-30T08:49:24Z
       
  • Surface polysaccharides from acinetobacter baumannii : structures and
           syntheses
    • Abstract: Publication date: Available online 22 October 2015
      Source:Carbohydrate Research
      Author(s): Denis Giguère
      The emergence of multidrug-resistance Acinetobacter baumannii requires novel approaches for prevention, treatment and diagnosis. The structures of surface polysaccharides from A. baumannii are valuable tools to understand pathogenesis, virulence and immunogenicity. The synthesis of bacterial mono- or polysaccharides may result in novel probes to become important therapeutic options in the fight against A. baumannii. This report exemplifies the relevance of glycochemistry for the development of new antibiotics.
      Graphical abstract image

      PubDate: 2015-10-26T10:23:33Z
       
  • Chemistry of xylopyranosides
    • Abstract: Publication date: Available online 23 October 2015
      Source:Carbohydrate Research
      Author(s): Karin Thorsheim, Anna Siegbahn, Richard E. Johnsson, Henrik Stålbrand, Sophie Manner, Göran Widmalm, Ulf Ellervik
      Xylose is one of the few monosaccharidic building blocks that are used by mammalian cells. In comparison with other monosaccharides, xylose is rather unusual and, so far, only found in two different mammalian structures, i.e. in the Notch receptor and as the linker between protein and glycosaminoglycan (GAG) chains in proteoglycans. Interestingly, simple soluble xylopyranosides can initiate the biosynthesis of soluble GAG chains but also function as inhibitors of important enzymes in the biosynthesis of proteoglycans. Furthermore, xylose is a major constituent of hemicellulosic xylans and thus one of the most abundant carbohydrates on Earth. Altogether, this has spurred a strong interest in xylose chemistry. The scope of this review is to describe synthesis of xylopyranosyl donors, as well as protective group chemistry, modifications, and conformational analysis of xylose.
      Graphical abstract image

      PubDate: 2015-10-26T10:23:33Z
       
  • A new method testing the orthogonality of different protecting groups
    • Abstract: Publication date: Available online 23 October 2015
      Source:Carbohydrate Research
      Author(s): Károly Ágoston, Ágnes Ágoston, Colin R. Dorgan, Péter Fügedi
      A new test was elaborated to identify a new set of orthogonal protecting groups. With the developed method eight different protecting groups were tested under various deprotection conditions and the complex reaction mixtures were analysed by HPLC. The developed method allows for quick identification of orthogonality using simple model structures.
      Graphical abstract image

      PubDate: 2015-10-26T10:23:33Z
       
  • Substrate-binding specificity of chitinase and chitosanase as revealed by
           active-site architecture analysis
    • Abstract: Publication date: Available online 21 October 2015
      Source:Carbohydrate Research
      Author(s): Shijia Liu, Shangjin Shao, Linlin Li, Zhi Cheng, Li Tian, Peiji Gao, Lushan Wang
      Chitinases and chitosanases, referred to as chitinolytic enzymes, are two important categories of glycoside hydrolases (GH) that play a key role in degrading chitin and chitosan, two naturally abundant polysaccharides. Here, we investigate the active site architecture of the major chitosanase (GH8, GH46) and chitinase families (GH18, GH19). Both charged (Glu, His, Arg, Asp) and aromatic amino acids (Tyr, Trp, Phe) are observed with higher frequency within chitinolytic active sites as compared to elsewhere in the enzyme structure, indicating significant roles related to enzyme function. Hydrogen bonds between chitinolytic enzymes and the substrate C2 functional groups, i.e. amino groups and N-acetyl groups, drive substrate recognition, while non-specific CH-π interactions between aromatic residues and substrate mainly contribute to tighter binding and enhanced processivity evident in GH8 and GH18 enzymes. For different families of chitinolytic enzymes, the number, type, and position of substrate atoms bound in the active site vary, resulting in different substrate-binding specificities. The data presented here explain the synergistic action of multiple enzyme families at a molecular level and provide a more reasonable method for functional annotation, which can be further applied towards the practical engineering of chitinases and chitosanases.
      Graphical abstract image

      PubDate: 2015-10-22T07:39:16Z
       
  • Synthesis and immunodetection of
           6-O-methyl-phosphoramidyl-α-D-galactose: A Campylobacter jejuni
           antigenic determinant
    • Abstract: Publication date: Available online 3 October 2015
      Source:Carbohydrate Research
      Author(s): Yuening Jiao, Zuchao Ma, Cheryl P. Ewing, Patricia Guerry, Mario A. Monteiro
      Campylobacter jejuni is a leading cause of traveller's diarrhea. Previously, we have shown that a C. jejuni capsule polysaccharide (CPS) conjugate vaccine can fully prevent C. jejuni diarrhea in non-human primates. C. jejuni CPSs are decorated with non-stoichiometric amounts of O-methyl phosphoramidate (MeOPN) units that are key serospecific markers. In the case of C. jejuni serotype complex HS23/36, the MeOPN are at positions 2 and 6 of the CPS galactose (Gal). We describe here the synthesis of the p-methoxyphenyl glycoside of MeOPN→6-α-D-Galp, and its immunodetection by antisera raised by C. jejuni CPS conjugates with MeOPN at primary positions. The synthetic approach in this work served as the foundation for a similar MeOPN→6-Gal construct used in a conjugate vaccine, whose synthesis, immunogenicity and efficacy will be described elsewhere.
      Graphical abstract image

      PubDate: 2015-10-06T09:08:20Z
       
 
 
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