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  Subjects -> CHEMISTRY (Total: 837 journals)
    - ANALYTICAL CHEMISTRY (48 journals)
    - CHEMISTRY (586 journals)
    - CRYSTALLOGRAPHY (22 journals)
    - ELECTROCHEMISTRY (26 journals)
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CHEMISTRY (586 journals)                  1 2 3 4 5 6 | Last

2D Materials     Hybrid Journal   (Followers: 6)
Accreditation and Quality Assurance: Journal for Quality, Comparability and Reliability in Chemical Measurement     Hybrid Journal   (Followers: 32)
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: 10)
ACS Macro Letters     Full-text available via subscription   (Followers: 21)
ACS Medicinal Chemistry Letters     Full-text available via subscription   (Followers: 24)
ACS Nano     Full-text available via subscription   (Followers: 206)
ACS Photonics     Full-text available via subscription   (Followers: 6)
ACS Synthetic Biology     Full-text available via subscription   (Followers: 11)
Acta Chemica Iasi     Open Access  
Acta Chimica Sinica     Full-text available via subscription  
Acta Chimica Slovaca     Open Access   (Followers: 6)
Acta Chromatographica     Full-text available via subscription   (Followers: 10)
Acta Facultatis Medicae Naissensis     Open Access   (Followers: 1)
Acta Metallurgica Sinica (English Letters)     Hybrid Journal   (Followers: 5)
adhäsion KLEBEN & DICHTEN     Hybrid Journal   (Followers: 5)
Adhesion Adhesives & Sealants     Hybrid Journal   (Followers: 5)
Adsorption Science & Technology     Full-text available via subscription   (Followers: 11)
Advanced Functional Materials     Hybrid Journal   (Followers: 41)
Advanced Science Focus     Free   (Followers: 1)
Advances in Chemical Engineering and Science     Open Access   (Followers: 23)
Advances in Chemical Science     Open Access   (Followers: 9)
Advances in Colloid and Interface Science     Full-text available via subscription   (Followers: 15)
Advances in Drug Research     Full-text available via subscription   (Followers: 18)
Advances in Enzyme Research     Open Access  
Advances in Fluorine Science     Full-text available via subscription   (Followers: 7)
Advances in Fuel Cells     Full-text available via subscription   (Followers: 13)
Advances in Heterocyclic Chemistry     Full-text available via subscription   (Followers: 8)
Advances in Materials Physics and Chemistry     Open Access   (Followers: 16)
Advances in Nanoparticles     Open Access   (Followers: 13)
Advances in Organometallic Chemistry     Full-text available via subscription   (Followers: 9)
Advances in Polymer Science     Hybrid Journal   (Followers: 39)
Advances in Protein Chemistry     Full-text available via subscription   (Followers: 6)
Advances in Protein Chemistry and Structural Biology     Full-text available via subscription   (Followers: 10)
Advances in Quantum Chemistry     Full-text available via subscription   (Followers: 6)
African Journal of Chemical Education     Open Access   (Followers: 1)
African Journal of Pure and Applied Chemistry     Open Access   (Followers: 6)
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: 5)
AMB Express     Open Access  
Ambix     Hybrid Journal   (Followers: 2)
American Journal of Applied Sciences     Open Access   (Followers: 30)
American Journal of Biochemistry and Biotechnology     Open Access   (Followers: 86)
American Journal of Biochemistry and Molecular Biology     Open Access   (Followers: 11)
American Journal of Chemistry     Open Access   (Followers: 19)
American Journal of Plant Physiology     Open Access   (Followers: 10)
American Mineralogist     Full-text available via subscription   (Followers: 7)
Analyst     Full-text available via subscription   (Followers: 38)
Angewandte Chemie     Hybrid Journal   (Followers: 22)
Angewandte Chemie International Edition     Hybrid Journal   (Followers: 128)
Annales UMCS, Chemia     Open Access   (Followers: 2)
Annals of Clinical Chemistry and Laboratory Medicine     Open Access  
Annual Reports in Computational Chemistry     Full-text available via subscription   (Followers: 1)
Annual Reports Section A (Inorganic Chemistry)     Full-text available via subscription   (Followers: 2)
Annual Reports Section B (Organic Chemistry)     Full-text available via subscription   (Followers: 6)
Annual Review of Chemical and Biomolecular Engineering     Full-text available via subscription   (Followers: 11)
Annual Review of Food Science and Technology     Full-text available via subscription   (Followers: 12)
Anti-Infective Agents     Hybrid Journal   (Followers: 1)
Antiviral Chemistry and Chemotherapy     Full-text available via subscription  
Applied Organometallic Chemistry     Hybrid Journal   (Followers: 4)
Applied Spectroscopy     Full-text available via subscription   (Followers: 15)
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: 4)
Autophagy     Full-text available via subscription   (Followers: 2)
Avances en Quimica     Open Access   (Followers: 1)
Biochemical Pharmacology     Hybrid Journal   (Followers: 6)
Biochemistry     Full-text available via subscription   (Followers: 151)
Biochemistry Insights     Open Access   (Followers: 4)
Biochemistry Research International     Open Access   (Followers: 4)
BioChip Journal     Hybrid Journal   (Followers: 1)
Bioinorganic Chemistry and Applications     Open Access   (Followers: 4)
Bioinspired Materials     Open Access  
Biointerface Research in Applied Chemistry     Open Access   (Followers: 1)
Biointerphases     Open Access  
Biomacromolecules     Full-text available via subscription   (Followers: 17)
Biomass Conversion and Biorefinery     Partially Free   (Followers: 6)
Biomedical Chromatography     Hybrid Journal   (Followers: 7)
Biomolecular NMR Assignments     Hybrid Journal   (Followers: 2)
BioNanoScience     Partially Free   (Followers: 5)
Bioorganic & Medicinal Chemistry     Hybrid Journal   (Followers: 30)
Bioorganic & Medicinal Chemistry Letters     Hybrid Journal   (Followers: 24)
Bioorganic Chemistry     Hybrid Journal   (Followers: 5)
Biopolymers     Hybrid Journal   (Followers: 14)
Biosensors     Open Access   (Followers: 3)
Biotechnic and Histochemistry     Hybrid Journal   (Followers: 3)
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: 13)
C - Journal of Carbon Research     Open Access  
Canadian Association of Radiologists Journal     Full-text available via subscription   (Followers: 3)
Canadian Journal of Chemistry     Full-text available via subscription   (Followers: 6)
Canadian Mineralogist     Full-text available via subscription   (Followers: 1)
Carbohydrate Research     Hybrid Journal   (Followers: 11)
Carbon     Hybrid Journal   (Followers: 63)
Catalysis for Sustainable Energy     Open Access   (Followers: 3)

        1 2 3 4 5 6 | Last

Journal Cover   Carbohydrate Research
  [SJR: 0.654]   [H-I: 83]   [11 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 0008-6215 - ISSN (Online) 0008-6215
   Published by Elsevier Homepage  [2812 journals]
  • Glycoprotein labeling with click chemistry (GLCC) and carbohydrate
           detection
    • Abstract: Publication date: 14 August 2015
      Source:Carbohydrate Research, Volume 412
      Author(s): Zhengliang L. Wu , Xinyi Huang , Andrew J. Burton , Karl A.D. Swift
      Molecular labeling and detection techniques are essential to research in life science. Here, a method for glycoprotein labeling/carbohydrate detection through glycan replacement, termed g lycoprotein l abeling with c lick c hemistry (GLCC), is described. In this method, a glycoprotein is first treated with specific glycosidases to remove certain sugar residues, a procedure that creates acceptor sites for a specific glycosyltransferase. A ‘clickable’ monosaccharide is then installed onto these sites by the glycosyltransferase. This modified glycoprotein is then conjugated to a reporter molecule using a click chemistry reaction. For glycoproteins that already contain vacant glycosylation sites, deglycosylation is not needed before the labeling step. As a demonstration, labeling on fetal bovine fetuin, mouse immunoglobulin IgG and bacterial expressed human TNFα and TNFβ are shown. Compared to traditional ways of protein labeling, labeling at glycosylation sites with GLCC is considerably more specific and less likely to have adverse effects, and, when utilized as a method for carbohydrate detection, this method is also highly specific and sensitive.
      Graphical abstract image

      PubDate: 2015-07-02T06:07:37Z
       
  • Synthesis and affinities of C3-symmetric thioglycoside-containing
           trimannosides
    • Abstract: Publication date: 14 August 2015
      Source:Carbohydrate Research, Volume 412
      Author(s): Jingjing Bi , Chuanfang Zhao , Wei Cui , Chaoli Zhang , Qiuli Shan , Yuguo Du
      Thioglycoside-containing trimannose analogs were designed and prepared to mimic the natural N-glycan core trisaccharide α-d-Man-(1→3)-[α-d-Man-(1→6)]-d-Man. (1→6)-S-Linked trimannoside 1 and its trivalent cluster 2 were synthesized in 11 and 15 steps, respectively, taking advantages of the armed mannopyranosyl trichloroacetimidate as glycosyl donor. Hemagglutination inhibition of the two new thiomannotriose analogs was preliminarily examined. Comparing to the parent trimannoside α-d-Man-(1→3)-[α-d-Man-(1→6)]-d-Man-OMe, the cluster mannotrioside 2 presented a comparable binding affinity to Con A, while the monomer 6-S-trimannoside 1 exhibited a slightly lower inhibition ability.
      Graphical abstract image

      PubDate: 2015-07-02T06:07:37Z
       
  • C-(2-Deoxy-d-arabino-hex-1-enopyranosyl)-oxadiazoles: synthesis of
           possible isomers and their evaluation as glycogen phosphorylase inhibitors
           
    • Abstract: Publication date: 14 August 2015
      Source:Carbohydrate Research, Volume 412
      Author(s): Éva Bokor , Eszter Szennyes , Tibor Csupász , Nóra Tóth , Tibor Docsa , Pál Gergely , László Somsák
      Synthetic methods were elaborated for d-glucals attached to oxadiazoles by a C–C bond. Introduction of the double bond was effected by either DBU induced elimination of PhCOOH from the O-perbenzoylated glucopyranosyl precursors or Zn/N-methylimidazole mediated reductive elimination from the 1-bromoglucopyranosyl starting compounds. Alternatively, heterocyclizations of 2-deoxy-d-arabino-hex-1-enopyranosyl cyanide were also carried out. Test compounds were obtained by Zemplén debenzoylation, however, none of them showed significant inhibition of rabbit muscle glycogen phosphorylase b.
      Graphical abstract image

      PubDate: 2015-07-02T06:07:37Z
       
  • Carbohydrate Chemistry: Proven Synthetic Methods, Vol. 1, Proven Synthetic
           Methods Series, Pavol Kováč, Ed. Boca Raton, FL 2011, 468 pages,
           CRC Press, Taylor and Francis Group, ISBN-13: 978-1439866894 and
           Carbohydrate Chemistry: Proven Synthetic Methods, Vol. 2, Proven Synthetic
           Methods Series, Gijsbert van der Marel and Jeroen Codee, Ed. Boca Raton,
           FL 2014, 333 pages, CRC Press, Taylor and Francis Group, ISBN-13:
           978-1439875940 (hardcover editions, both are also available in eBook
           format). Series Editor: Pavol Kováč.
    • Abstract: Publication date: 14 August 2015
      Source:Carbohydrate Research, Volume 412
      Author(s): Nicola L.B. Pohl



      PubDate: 2015-07-02T06:07:37Z
       
  • Alkyl-imidazolium glycosides: non-ionic—cationic hybrid surfactants
           from renewable resources
    • Abstract: Publication date: 14 August 2015
      Source:Carbohydrate Research, Volume 412
      Author(s): Abbas Abdulameer Salman , Mojtaba Tabandeh , Thorsten Heidelberg , Rusnah Syahila Duali Hussen , Hapipah Mohd Ali
      A series of surfactants combining carbohydrate and imidazolium head groups were prepared and investigated on their assembly behavior. The presence of the imidazolium group dominated the interactions of the surfactants, leading to high CMCs and large molecular surface areas, reflected in curved rather than lamellar surfactant assemblies. The carbohydrate, on the other hand, stabilized molecular assemblies slightly and reduced the surface tension of surfactant solutions considerably. A comparative emulsion study discourages the use of pure alkyl imidazolium glycosides owing to reduced assembly stabilities compared with APGs. However, the surfactants are believed to have potential as component in carbohydrate based surfactant mixtures.
      Graphical abstract image

      PubDate: 2015-07-02T06:07:37Z
       
  • Core oligosaccharide of Escherichia coli B—the structure required
           for bacteriophage T4 recognition
    • Abstract: Publication date: 2 September 2015
      Source:Carbohydrate Research, Volume 413
      Author(s): Marta Kaszowska , Tomasz Niedziela , Anna Maciejewska , Jolanta Lukasiewicz , Wojciech Jachymek , Czeslaw Lugowski
      The structure of Escherichia coli B strain PCM 1935 core oligosaccharide has been investigated by 1H and 13C NMR spectroscopy, MALDI-TOF MS and ESI MSn. It was concluded that the core oligosaccharide is a pentasaccharide with the following structure: ESI MS/MS analysis revealed that the glycine (a minor component) is linked to the →3,7)-l-α-d-Hepp-(1→ residue.
      Graphical abstract image

      PubDate: 2015-07-02T06:07:37Z
       
  • Structure of the O-specific polysaccharide from the legume endosymbiotic
           bacterium Ochrobactrum cytisi strain ESC1T
    • Abstract: Publication date: 2 September 2015
      Source:Carbohydrate Research, Volume 413
      Author(s): Malgorzata Pac , Iwona Komaniecka , Katarzyna Zamlynska , Anna Turska-Szewczuk , Adam Choma
      The O-specific polysaccharide was obtained from the lipopolysaccharide of the legume-endosymbiotic bacterium Ochrobactrum cytisi strain ESC1T and studied by chemical analyses and 1D and 2D NMR spectroscopy. The polysaccharide was found to have a disaccharide repeating unit containing α-d-fucose and β-N-acetyl-d-galactosamine residues connected via (1→3)-glycosidic bonds, resulting in the following structure: →3)-α-d-Fucp-(1→3)-β-d-GalpNAc-(1→ The d-GalpNAc residue was nonstoichiometrically substituted with a 4-O-methyl group (∼10%) or with a 4,6-O-(1-carboxy)-ethylidene residue (pyruvyl group) (∼10%).
      Graphical abstract image

      PubDate: 2015-07-02T06:07:37Z
       
  • Structure of the O-specific polysaccharide from a marine bacterium
           Cellulophaga tyrosinoxydans
    • Abstract: Publication date: 2 September 2015
      Source:Carbohydrate Research, Volume 413
      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 tyrosinoxydans and studied by chemical analyses along with 1H and 13C NMR spectroscopy, including 2D 1H, 1H COSY, TOCSY, ROESY, 1Н, 13С HSQC, HMBC and H2BC experiments. The following new structure of the O-polysaccharide of C. tyrosinoxydans containing l-fucose (Fuc), N-acetyl-d-glucosamine (GlcNAc), 4-acetamido-4,6-dideoxy-d-glucose (Qui4NAc) and two l-rhamnose residues (Rha) was established: .
      Graphical abstract image

      PubDate: 2015-07-02T06:07:37Z
       
  • Structural elucidation of an asparagine-linked oligosaccharide from the
           hyperthermophilic archaeon, Archaeoglobus fulgidus
    • Abstract: Publication date: 2 September 2015
      Source:Carbohydrate Research, Volume 413
      Author(s): Daisuke Fujinami , James Nyirenda , Shunsuke Matsumoto , Daisuke Kohda
      The genome of the hyperthermophilic archaeon, Archaeoglobus fulgidus, contains three paralogous AglB genes that encode oligosaccharyltransferase (OST) proteins. The OST enzymes catalyze the transfer of an oligosaccharide chain from lipid-linked oligosaccharides (LLO) to asparagine residues in proteins. The detergent-solubilized membrane fractions prepared from cultured A. fulgidus cells contain both OST and LLO. The addition of a peptide containing the glycosylation sequon produced oligosaccharide chains attached to a structurally defined peptide. To facilitate the NMR analysis, the cells were grown in rich medium supplemented with 13 C-glucose, to label the LLOs metabolically. The MS analysis of the glycopeptide revealed that the glucose and galactose residues were nearly fully 13C-labeled, but the mannose residues were fractionally labeled with about 20% efficiency. An immunodetection experiment revealed that the longest AglB paralog (AfAglB-L) was expressed in the membrane fractions under our cell culture conditions, while the other two shorter AglB paralogs (AfAglB-S1 and AfAglB-S2) were not. Thus, the oligosaccharide chain analyzed in this study was the product of AfAglB-L. The N-glycan consists of eight hexose residues, as follows: The α1,3-linked glucose is an optional residue branching from the distal mannose residue. The MS analysis of the minor HPLC peak of the in vitro oligosaccharyl transfer products also revealed an optional sulfate modification on the glucose residue directly linked to the Asn residue. The present data will be useful for structural and functional studies of the N-glycosylation system of A. fulgidus.
      Graphical abstract image

      PubDate: 2015-07-02T06:07:37Z
       
  • Photoinitiated hydrothiolation of pyranoid exo-glycals: the d-galacto and
           d-xylo cases
    • Abstract: Publication date: 2 September 2015
      Source:Carbohydrate Research, Volume 413
      Author(s): János József , László Juhász , Tünde Zita Illyés , Magdolna Csávás , Anikó Borbás , László Somsák
      Radical-mediated addition reactions of thiols to O-peracetylated exo-galactal and exo-xylal with 2,2-dimethoxy-2-phenylacetophenone as the photoinitiator resulted in high yielding formation of the corresponding β-d-glycopyranosylmethyl-sulfide derivatives (2,6-anhydro-1-deoxy-1-S-substituted-1-thio-alditols) with exclusive regio- and very high stereoselectivity, including disaccharide mimicks with Gly-CH2-S-Gly scaffolds.
      Graphical abstract image

      PubDate: 2015-07-02T06:07:37Z
       
  • Mass spectrometry-based N-linked glycomic profiling as a means for
           tracking pancreatic cancer metastasis
    • Abstract: Publication date: 2 September 2015
      Source:Carbohydrate Research, Volume 413
      Author(s): Hae-Min Park , Mintai Peter Hwang , Yoon-Woo Kim , Kyoung-Jin Kim , Jang Mi Jin , Young Hwan Kim , Yung-Hun Yang , Kwan Hyi Lee , Yun-Gon Kim
      The aberrant glycosylation profile on the surface of cancer cells has been recognized for its potential diagnostic value towards assessing tumor progression. In this study, we initially investigate N-glycan profiles on the surface of normal (HPDE) and cancerous (Capan-1, Panc-1, and MIA PaCa-2) pancreatic cell lines, which are from different sites of pancreatic tumor. The enzymatically deglycosylated total N-glycans are permethylated via a quantitative solid-phase method and then analyzed by using MALDI-TOF MS and MALDI-QIT-TOF MS. We demonstrate that the level of high-mannose type glycans is higher among Capan-1 cells—pancreatic cancer cells that have metastasized to the liver—than that observed among Panc-1 and MIA PaCa-2 cells—pancreatic cancer cells from the pancreas duct head and tail regions, respectively. Furthermore, the relative abundance of highly-branched sialyted N-glycans is significantly up-regulated on Panc-1 and MIA PaCa-2 pancreatic cancer cells compared to that of normal HPDE pancreas cells. Taken together, these results indicate that specific N-glycosylation profile changes in pancreatic cancer cells can be used to not only distinguish between normal and cancerous cells but also provide more information on their location and metastatic potential.
      Graphical abstract image

      PubDate: 2015-07-02T06:07:37Z
       
  • Studies on antioxidative and immunostimulating fucogalactan of the edible
           mushroom Macrolepiota dolichaula
    • Abstract: Publication date: 2 September 2015
      Source:Carbohydrate Research, Volume 413
      Author(s): Surajit Samanta , Ashis K. Nandi , Ipsita K. Sen , Prasenjit Maity , Manabendra Pattanayak , K. Sanjana P. Devi , Somanjana Khatua , Tapas K. Maiti , Krishnendu Acharya , Syed S. Islam
      A water soluble fucogalactan (PS-II) of an average molecular weight ∼1.2×105 Da was isolated from the aqueous extract of an edible mushroom Macrolepiota dolichaula. It was composed of fucose, galactose and 3-O-methyl galactose in a molar ratio of nearly 1:4:1. Structural characterization of PS-II was carried out using total hydrolysis, methylation analysis, Smith degradation, and 1D/2D NMR experiments. These results indicated that the proposed repeating unit of the PS-II had a backbone chain consisting of four (1→6)- linked α-d-Galp residues, one residue methylated at O-3, and another one substituted at O-2 by (1→2)-α-d-Galp residue, which is terminated with a α-l-Fucp moiety. The PS-II exhibited the antioxidant properties in different in vitro test systems, and also showed in vitro macrophage activation in RAW 264.7 cell line as well as splenocyte and thymocyte activation in mouse cell culture medium.
      Graphical abstract image

      PubDate: 2015-07-02T06:07:37Z
       
  • Structure of the neutral capsular polysaccharide of Acinetobacter
           baumannii NIPH146 that carries the KL37 capsule gene cluster
    • Abstract: Publication date: 2 September 2015
      Source:Carbohydrate Research, Volume 413
      Author(s): Nikolay P. Arbatsky , Mikhail M. Shneider , Johanna J. Kenyon , Alexander S. Shashkov , Anastasiya V. Popova , Konstantin A. Miroshnikov , Nikolay V. Volozhantsev , Yuriy A. Knirel
      Capsular polysaccharide (CPS) was isolated from Acinetobacter baumannii NIPH146, and the following structure of branched pentasaccharide repeating unit was established by sugar analyses along with 1D and 2D NMR spectroscopy: In comparison to most other known capsular polysaccharides of A. baumannii, the CPS studied is neutral and lacks any specific monosaccharide component. The synthesis, assembly and export of this structure could be attributed to genes in a novel capsule biosynthesis gene cluster, designated KL37, which was found in the NIPH146 genome. The CPS of A. baumannii NIPH146 shares the α-d-Galp-(1→6)-β-d-Glcp-(1→3)-d-GalpNAc-(1→ trisaccharide fragment with the CPS units of several A. baumannii strains, including ATCC 17978 and LUH 5537 that carry the KL3 and KL22 gene clusters, respectively. KL37 contains two genes for glycosyltransferases that are related to two glycosyltransferase genes present in both KL3 and KL22, and the encoded proteins could be tentatively assigned to linkages between sugars in the CPS repeat.
      Graphical abstract image

      PubDate: 2015-07-02T06:07:37Z
       
  • Triterpenoid saponins from the root bark of Schima superba and their
           cytotoxic activity on B16 melanoma cell line
    • Abstract: Publication date: 2 September 2015
      Source:Carbohydrate Research, Volume 413
      Author(s): Chun Wu , Rong-Liu Zhang , Hong-Yu Li , Chen Hu , Bai-Lian Liu , Yao-Lan Li , Guang-Xiong Zhou
      Eight new oleanane-type triterpenoid saponins, schisusaponins A-H, along with eight known triterpenoid saponins, were isolated from the root bark of Schima superb (Theaceae). Their structures were elucidated on the basis of extensive spectroscopic analyses and chemical methods. The cytotoxicity of the new compounds against B16 melanoma cells was assessed. Among the isolated new saponins, schisusaponins C and E showed more potent effects (with IC50 values of 10.08 and 10.89 μM) than vinblastine (with an IC50 value of 19.48 μM).
      Graphical abstract image

      PubDate: 2015-07-02T06:07:37Z
       
  • Synthesis of NAG-thiazoline-derived inhibitors for
           β-N-acetyl-d-hexosaminidases
    • Abstract: Publication date: 2 September 2015
      Source:Carbohydrate Research, Volume 413
      Author(s): Hanchu Kong , Wei Chen , Huizhe Lu , Qing Yang , Yanhong Dong , Daoquan Wang , Jianjun Zhang
      β-N-Acetyl-d-hexosaminidases are responsible for the metabolism of glycoconjugates in diverse physiological processes that are important targets for medicine and pesticide development. Fourteen new NAG-thiazoline derivatives were synthesized by cyclization and click reaction using d-glucosamine hydrochloride as the starting material. All the compounds created were characterized by NMR and HRMS spectra. A preliminary bioassay, using four enzymes from two β-N-acetyl-d-hexosaminidase families, showed that most of the compounds synthesized exhibit selective inhibition of GH84 β-N-acetyl-d-hexosaminidase. Among the compounds tested, compounds 5a (IC50=12.6 μM, hOGA) and 5e (IC50=12.5 μM, OfOGA) proved to be a highly selective and potent inhibitor.
      Graphical abstract image

      PubDate: 2015-07-02T06:07:37Z
       
  • Enzymatic synthesis of hyaluronan hybrid urinary trypsin inhibitor
    • Abstract: Publication date: 2 September 2015
      Source:Carbohydrate Research, Volume 413
      Author(s): Ikuko Kakizaki , Ryoki Takahashi , Miho Yanagisawa , Futaba Yoshida , Keiichi Takagaki
      Human urinary trypsin inhibitor is a proteoglycan that has a single low-sulfated chondroitin 4-sulfate chain at the seryl residue in position 10 of the core protein as a glycosaminoglycan moiety, and is used as an anti-inflammatory medicine based on the protease inhibitory activity of the core protein. However, the functions of the glycosaminoglycan moiety have not yet been elucidated in detail. In the present study, the glycosaminoglycan chains of a native urinary trypsin inhibitor were remodeled to hyaluronan chains, with no changes to the core protein, using transglycosylation as a reverse reaction of the hydrolysis of bovine testicular hyaluronidase, and the properties of the hybrid urinary trypsin inhibitor were then analyzed. The trypsin inhibitory activitiy of the hyaluronan hybrid urinary trypsin inhibitor was similar to that of the native type; however, its inhibitory effect on the hydrolysis of hyaluronidase were not as strong as that of the native type. This result demonstrated that the native urinary trypsin inhibitor possessed hyaluronidase inhibitory activity on its chondroitin sulfate chain. The hyaluronan hybrid urinary trypsin inhibitors obtained affinity to a hyaluronan-binding protein not exhibited by the native type. The interactions between the hyaluronan hybrid urinary trypsin inhibitors and phosphatidylcholine (abundant in the outer layer of plasma membrane) were stronger than that of the native type. Hyaluronan hybrid urinary trypsin inhibitors may be useful for investigating the functions of the glycosaminoglycan chains of urinary trypsin inhibitors and hyaluronan, and our hybrid synthesizing method may be used widely in research for future medical applications.
      Graphical abstract image

      PubDate: 2015-07-02T06:07:37Z
       
  • Direct aqueous synthesis of non-protected glycosyl sulfoxides; weak
           inhibitory activity against glycosidases
    • Abstract: Publication date: 2 September 2015
      Source:Carbohydrate Research, Volume 413
      Author(s): Stewart R. Alexander , Andrew J.A. Watson , Antony J. Fairbanks
      A flavinium catalyst, in conjunction with hydrogen peroxide as stoichiometric oxidant, allowed the aqueous conversion of non-protected thioglycosides into the corresponding glycosyl sulfoxides. These glycosyl sulfoxides displayed only very weak inhibitory activity against corresponding glycosidases.
      Graphical abstract image

      PubDate: 2015-07-02T06:07:37Z
       
  • Probing the roles of conserved residues in uridyltransferase domain
           of Escherichia coli K12 GlmU by site-directed mutagenesis
    • Abstract: Publication date: 2 September 2015
      Source:Carbohydrate Research, Volume 413
      Author(s): Shuaishuai Wang , Xuan Fu , Yunpeng Liu , Xian-wei Liu , Lin Wang , Junqiang Fang , Peng George Wang
      N-Acetylglucosamine-1-phosphate uridyltransferase (GlmU) is a bifunctional enzyme that catalyzes both acetyltransfer and uridyltransfer reactions in the prokaryotic UDP-GlcNAc biosynthesis pathway. Our previous study demonstrated that the uridyltransferase domain of GlmU (tGlmU) exhibited a flexible substrate specificity, which could be further applied in unnatural sugar nucleotides preparation. However, the structural basis of tolerating variant substrates is still not clear. Herein, we further investigated the roles of several highly conserved amino acid residues involved in substrate binding and recognition by structure- and sequence-guided site-directed mutagenesis. Out of total 16 mutants designed, tGlmU Q76E mutant which had a novel catalytic activity to convert CTP and GlcNAc-1P into unnatural sugar nucleotide CDP-GlcNAc was identified. Furthermore, tGlmU Y103F and N169R mutants were also investigated to have enhanced uridyltransferase activities compared with wide-type tGlmU.
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      PubDate: 2015-07-02T06:07:37Z
       
  • Synthesis of glycotriazololipids and observations on their self-assembly
           properties
    • Abstract: Publication date: 2 September 2015
      Source:Carbohydrate Research, Volume 413
      Author(s): Mohit Tyagi , K. P. Ravindranathan Kartha
      Various carbohydrate-anchored triazole-linked lipids prepared by solvent-free mechanochemical azide-alkyne click reaction, on analysis by TEM, have been found to spontaneously self-assemble in solvents leading to structures of interesting physicochemical attributes. Interestingly, analogous compounds based on different sugars (e.g., d-glucose, and d-galactose, as also d-lactose) assemble in patterns distinctly different from each other thus reiterating the fact that the structure of the sugar as well as that of the lipid are important factors that determine the size and shape of the supramolecular assembly formed. Besides, the molecular self-assembly was also found to be solvent-as well as temperature-dependent.
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      PubDate: 2015-07-02T06:07:37Z
       
  • NMR structural determination of unique invertebrate glycosaminoglycans
           endowed with medical properties
    • Abstract: Publication date: 2 September 2015
      Source:Carbohydrate Research, Volume 413
      Author(s): Vitor H. Pomin
      Glycosaminoglycans (GAGs) are sulfated polysaccharides of complex structure endowed with numerous biomedical functions. Although ubiquitously distributed in vertebrates, GAGs can also occur in certain terrestrial or marine invertebrates. Solution nuclear magnetic resonance (NMR) spectroscopy has been the analytical technique mostly employed in structural characterization of GAGs from any source. This review aims at illustrating the application of NMR in structural determination of few representative invertebrate GAG examples of unique structures and endowed with therapeutic actions. They are the holothurian fucosylated chondroitin sulfate, the acharan sulfate isolated from the snail Achatina fulica, the dermatan sulfates with distinct sulfation patterns extracted from ascidian species, the sulfated glucuronic acid-containing heparan sulfate isolated from the gastropode Nodipecten nodosum, and the hybrid heparin/heparan sulfate molecule obtained from the shrimp Litopenaeus vannamei. These invertebrate GAGs exhibit distinct structures when compared to those extracted from mammalian GAGs. The distinct structures of the invertebrate GAGs lead also to different mechanisms of actions as compared to the mammalian GAG standards. Invertebrate GAGs comprise promising therapeutic candidates in fights against diseases. Solution NMR has been playing a pivotal role in this carbohydrate-based drug research, discovery and development.
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      PubDate: 2015-07-02T06:07:37Z
       
  • Direct Mitsunobu monoesterification of N-protected tobramycin competes
           with intramolecular pyrrolidine formation in ester prodrug synthesis
    • Abstract: Publication date: 2 September 2015
      Source:Carbohydrate Research, Volume 413
      Author(s): Sabina Quader , Sue E. Boyd , Ian D. Jenkins , Todd A. Houston
      Unlike the related aminoglycoside neomycin B, N-protected tobramycin can be selectively esterified at its sole, primary hydroxyl group under Mitsunobu conditions. However, depending on the reaction conditions, the reaction can take a different course with intramolecular cyclization of an N-Boc amine leading to formation of an unusual tobramycin pyrrolidine derivative as the major reaction product.
      Graphical abstract image

      PubDate: 2015-07-02T06:07:37Z
       
  • Structure of the O-specific polysaccharide from the deep-sea marine
           bacterium Idiomarina abyssalis КММ 227T containing a
           2-O-sulfate-3-N-(4-hydroxybutanoyl)-3,6-dideoxy-d-glucose
    • Abstract: Publication date: 2 September 2015
      Source:Carbohydrate Research, Volume 413
      Author(s): Maxim S. Kokoulin , Nadezhda A. Komandrova , Anatoly I. Kalinovskiy , Svetlana V. Tomshich , Lyudmila A. Romanenko , Victor V. Vaskovsky
      The O-specific polysaccharide was isolated from the lipopolysaccharide of type strain Idiomarina abyssalis КММ 227T and studied by sugar analysis, Smith degradation, and two-dimensional 1H and 13C NMR spectroscopy including 1H,1H-TOCSY, 1H,1H-COSY, 1H,1H-ROESY, 1H,13C-HSQC, 1H,13C-HMBC, 1H,13C-H2BC and 1H,13C-HSQC-TOCSY experiments. The new structure of the O-specific polysaccharide of I. abyssalis КММ 227T containing 2-O-sulfate-3-N-(4-hydroxybutanoyl)-3,6-dideoxy-d-glucose was established:
      Graphical abstract image

      PubDate: 2015-07-02T06:07:37Z
       
  • Structure determination of the neutral exopolysaccharide produced by
           Lactobacillus delbrueckii subsp. bulgaricus OLL1073R-1
    • Abstract: Publication date: 2 September 2015
      Source:Carbohydrate Research, Volume 413
      Author(s): Marie-Rose Van Calsteren , Fleur Gagnon , Junko Nishimura , Seiya Makino
      The neutral exopolysaccharide (NPS) of Lactobacillus delbrueckii subsp. bulgaricus strain OLL1073R-1 was purified and characterized. The molecular mass was 5.0×106 g/mol. Sugar and absolute configuration analyses gave the following composition: d-Glc, 1; d-Gal, 1.5. The NPS was also submitted to periodate oxidation followed by borohydride reduction and Smith degradation. Sugar and methylation analyses, 1H and 13C nuclear magnetic resonance, and mass spectrometry of the NPS or of its specifically modified products allowed determining the repeating unit sequence: {2)Glc(α1–3)Glc(β1–3)[Gal(β1–4)]Gal(β1–4)Gal(α1–} n . The structure is compared to that of exopolysaccharides produced by other Lactobacillus bulgaricus strains.
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      PubDate: 2015-07-02T06:07:37Z
       
  • Structural investigation of cell wall polysaccharides of Lactobacillus
           delbrueckii subsp. bulgaricus 17
    • Abstract: Publication date: 2 September 2015
      Source:Carbohydrate Research, Volume 413
      Author(s): E. Vinogradov , I. Sadovskaya , A. Cornelissen , D. van Sinderen
      Lactobacilli are valuable strains for commercial (functional) food fermentations. Their cell surface-associated polysaccharides (sPSs) possess important functional properties, such as acting as receptors for bacteriophages (bacterial viruses), influencing autolytic characteristics and providing protection against antimicrobial peptides. The current report provides an elaborate molecular description of several surface carbohydrates of Lactobacillus delbrueckii subsp. bulgaricus strain 17. The cell surface of this strain was shown to contain short chain poly(glycerophosphate) teichoic acids and at least two different sPSs, designated here as sPS1 and sPS2, whose chemical structures were examined by 2D nuclear magnetic resonance spectroscopy and methylation analysis. Neutral branched sPS1, extracted with n-butanol, was shown to be composed of hexasaccharide repeating units (-[α-d-Glcp-(1-3)-]-4-β-l-Rhap2OAc-4-β-d-Glcp-[α-d-Galp-(1-3)]-4-α-Rhap-3-α-d-Galp-), while the major component of the TCA-extracted sPS2 was demonstrated to be a linear d-galactan with the repeating unit structure being (-[Gro-3P-(1-6)-]-3-β-Galf-3-α-Galp-2-β-Galf-6-β-Galf-3-β-Galp-).
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      PubDate: 2015-07-02T06:07:37Z
       
  • Determination of the degree of acetylation and the distribution of acetyl
           groups in chitosan by HPLC analysis of nitrous acid degraded and PMP
           labeled products
    • Abstract: Publication date: 2 September 2015
      Source:Carbohydrate Research, Volume 413
      Author(s): Zhangrun Han , Yangyang Zeng , Hong Lu , Lijuan Zhang
      Chitin is one of the most abundant polysaccharides on earth. It consists of repeating β-1,4 linked N-acetylated glucosamine (A) units. Chitosan is an N-deacetylated product of chitin. Chitosan and its derivatives have broad medical applications as drugs, nutraceuticals, or drug delivery agents. However, a reliable analytical method for quality control of medically used chitosans is still lacking. In current study, nitrous acid was used to cleave all glucosamine residues in chitosan into 2,5-anhydromannose (M) or M at the reducing end of di-, tri-, and oligosaccharides. PMP, i.e. 1-phenyl-3-methyl-5-pyrazolone, was used to label all the Ms. Online UV detection allowed quantification of all M-containing UV peaks whereas online MS analysis directly identified 11 different kinds of mono-, di-, tri-, and oligosaccharides that correlated each oligosaccharide with specific UV peak after HPLC separation. The DA (degree of acetylation) for chitosans was calculated based on the A/(A+M) value derived from the UV data. This newly developed method had several advantages for quality control of chitosan: 1. the experimental procedures were extensively optimized; 2. the reliability of the method was confirmed by online LC-MS analysis; 3. the DA value was obtainable based on the UV data after HPLC analysis, which was comparableto that of 1H NMR and conductometric titration analyses; 4. finally and most importantly, this method could be used to obtain the DA as well as chemical acetylation/deacetylation mechanisms for chitosan by any laboratory equipped with a HPLC and an online UV detector.
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      PubDate: 2015-07-02T06:07:37Z
       
  • Heteroglycan of an edible mushroom Termitomyces clypeatus: structure
           elucidation and antioxidant properties
    • Abstract: Publication date: 2 September 2015
      Source:Carbohydrate Research, Volume 413
      Author(s): Manabendra Pattanayak , Surajit Samanta , Prasenjit Maity , Ipsita K. Sen , Ashis K. Nandi , Dilip K. Manna , Payel Mitra , Krishnendu Acharya , Syed S. Islam
      A water-soluble heteroglycan (PS) of an average molecular weight ∼1.98 ×105 Da was isolated from the aqueous extract of an edible mushroom Termitomyces clypeatus (R. Heim). The structure of the polysaccharide (PS) was established using total hydrolysis, methylation analysis, Smith degradation, and 1D/2D NMR experiments. Total hydrolysis indicated the presence of d-glucose, d-galactose, d-mannose, and l-fucose in a molar ratio of 4.10:1.95:1.0:0.95, respectively. The chemical and NMR analysis indicated the presence of a repeating unit with a backbone consisting of one each of the residues (1→3)-α-d-galactopyranosyl, (1→3)-α-d-mannopyranosyl, (1→3)-α-d-glucopyranosyl, (1→3)-β-d-glucopyranosyl, (1→6)-β-d-glucopyranosyl, and (1→6)-α-d-galactopyranosyl, respectively. The (1→3)-α-d-mannopyranosyl residue was found branched at O-2 with terminal α-l-fucopyranosyl moiety and (1→3)-β-d-glucopyranosyl residue was branched at O-6 with terminal α-d-glucopyranosyl residue. The PS exhibited antioxidant properties.
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      PubDate: 2015-07-02T06:07:37Z
       
  • Synthesis of mannoheptose derivatives and their evaluation as inhibitors
           
    • Abstract: Publication date: 14 August 2015
      Source:Carbohydrate Research, Volume 412
      Author(s): Anna Hofmann , Roman Sommer , Dirk Hauck , Julia Stifel , Inigo Göttker-Schnetmann , Alexander Titz
      Biofilm formation and chronic infections with Pseudomonas aeruginosa depend on lectins produced by the bacterium. The bacterial C-type lectin LecB binds to the two monosaccharides l-fucose and d-mannose and conjugates thereof. Previously, d-mannose derivatives with amide and sulfonamide substituents at C6 were reported as potent inhibitors of the bacterial lectin LecB and LecB-mediated bacterial surface adhesion. Because d-mannose establishes a hydrogen bond via its 6-OH group with Ser23 of LecB in the crystal structure and may be beneficial for binding affinity, we extended d-mannose and synthesized mannoheptoses bearing the free 6-OH group as well as amido and sulfonamido-substituents at C7. Two series of diastereomeric mannoheptoses were synthesized and the stereochemistry was determined by X-ray crystallography. The potency of the mannoheptoses as LecB inhibitors was assessed in a competitive binding assay. The data reveal a diastereoselectivity of LecB for (6S)-mannoheptose derivatives with increased activity over methyl α-d-mannoside.
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      PubDate: 2015-07-02T06:07:37Z
       
  • The method of integrated kinetics and its applicability to the
           exo-glycosidase-catalyzed hydrolyses of p-nitrophenyl glycosides
    • Abstract: Publication date: 14 August 2015
      Source:Carbohydrate Research, Volume 412
      Author(s): Anna S. Borisova , Sumitha K. Reddy , Dina R. Ivanen , Kirill S. Bobrov , Elena V. Eneyskaya , Georgy N. Rychkov , Mats Sandgren , Henrik Stålbrand , Michael L. Sinnott , Anna A. Kulminskaya , Konstantin A. Shabalin
      In the present work we suggest an efficient method, using the whole time course of the reaction, whereby parameters k cat, K m and product K I for the hydrolysis of a p-nitrophenyl glycoside by an exo-acting glycoside hydrolase can be estimated in a single experiment. Its applicability was demonstrated for three retaining exo-glycoside hydrolases, β-xylosidase from Aspergillus awamori, β-galactosidase from Penicillium sp. and α-galactosidase from Thermotoga maritima (TmGalA). During the analysis of the reaction course catalyzed by the TmGalA enzyme we had observed that a non-enzymatic process, mutarotation of the liberated α-d-galactose, affected the reaction significantly.
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      PubDate: 2015-07-02T06:07:37Z
       
  • Preparation of a polyclonal antibody that recognizes a unique
           galactoseβ1-4fucose disaccharide epitope
    • Abstract: Publication date: 14 August 2015
      Source:Carbohydrate Research, Volume 412
      Author(s): Tomoharu Takeuchi , Kazusa Nishiyama , Saori Saito , Mayumi Tamura , Takashi J. Fuwa , Shoko Nishihara , Hideyo Takahashi , Hideaki Natsugari , Yoichiro Arata , Ken-ichi Kasai
      Galactoseβ1-4fucose (Galβ1-4Fuc) is a unique disaccharide unit that has been found only in the N-glycans of protostomia. We demonstrated that this unit has a role as an endogenous ligand for Caenorhabditis elegans galectins. This unit is also recognized by fungal and mammalian galectins possibly as a non-self glycomarker. In order to clarify its biological function, we made a polyclonal antibody using (Galβ1-4Fuc)n-BSA as the antigen, which was prepared by crosslinking Galβ1-4Fuc-O–(CH2)2–SH and BSA. The binding specificity of the antibody was analyzed by frontal affinity chromatography, and it was confirmed that it recognizes naturally occurring N-glycans containing the Galβ1-4Fuc unit linked to the reducing-end GlcNAc via α1-6 linkage. By western blotting analysis, the antibody was also found to bind to (Galβ1-4Fuc)n-BSA but not to BSA or asialofetuin, which has N-glycan chains containing Galβ1-4GlcNAc. Western blotting experiments also revealed presence of stained proteins in crude extracts of C. elegans, the parasitic nematode Ascaris suum, and the allergenic mite Dermatophagoides pteronyssinus, while those from Drosophila melanogaster, Mus musculus, and the allergenic mites Dermatophagoides farinae and Tyrophagus putrescentiae were negative. This antibody should be a very useful tool for research on the distribution of the Galβ1-4Fuc disaccharide unit in glycans in a wide range of organisms.
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      PubDate: 2015-07-02T06:07:37Z
       
  • Development of new methods for determining the heparanase enzymatic
           activity
    • Abstract: Publication date: 14 August 2015
      Source:Carbohydrate Research, Volume 412
      Author(s): Carina Mucciolo Melo , Ivarne Luis Santos Tersariol , Helena Bonciani Nader , Maria Aparecida Silva Pinhal , Marcelo Andrade Lima
      Introduction Heparanase is a mammalian endo-β-glucuronidase. Notwithstanding its importance in various pathological and non-pathological events few straightforward methods for heparanase enzymatic activity has been stated. The aim of this study was to develop two heparanase activity assays to cover a whole range of applications. First, a fast and easy method based on commercial homogenous substrate, fondaparinux, was described. The other method is a quantitative assay based on biotinylated heparan sulfate that uses an easier technique to immobilize the substrate in a 96-well plate. Methods: 1) The heparanase recombinant enzyme and fondaparinux were incubated overnight. After incubation, a fluorescent redox marker, resazurin, was added. The reduction of resazurin depends on the amount of glucuronic acid released by heparanase digestion. Fluorescence measurements were done using excitation and emission wavelengths of 560 nm and 590 nm, respectively. Methods: 2) The 96-well plate was incubated with protamine sulfate. Subsequently, biotinylated heparan sulfate was immobilized. The enzymatic assay was performed using chimeric recombinant heparanase at different concentrations. In sequence, the immobilized biotinylated heparan sulfate that was not digested by recombinant heparanase was bound to streptavidin conjugated with europium. Fluorescence was measured using a time-resolved fluorometer. Conclusion Both methods have high sensitivity and can be used to detect heparanase activity. Fondaparinux assay is a quick and easy method for screening of heparanase inhibitors using recombinant enzyme or bacterial crude extract. Biotinylated heparan sulfate assay can be used for quantitative analysis in biological samples and protamine sulfate showed been capable to immobilized heparan sulfate.
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      PubDate: 2015-07-02T06:07:37Z
       
  • Synthesis, characterization and in vitro evaluation of a series of
           novel polyrotaxane-based delivery system for artesunate
    • Abstract: Publication date: 14 August 2015
      Source:Carbohydrate Research, Volume 412
      Author(s): Xiao-Shun Gong , Rui-Jian Jiang , Xia-Li Liao , Hu-Die Xie , Xue Ma , Chuan-Zhu Gao , Bo Yang , Yu-Lin Zhao
      A series of novel artesunate-polyrotaxanes (ATS-PRs) with folic acid capped, in which artesunate (ATS) was covalently bound to a cyclodextrin (CD) of the polyrotaxane (PR), were synthesized and were characterized by NMR, XRD, TG and DSC. The cytotoxicities of ATS-PRs on human colon cancer cell lines HT-29, SW480, HTC116 and DLD-1 showed that their antitumor activities were better than that of artesunate (ATS) and dihydroartemisinin (DHA). These ATS-PRs may provide a useful approach to the development of a highly effective drug candidate for the chemotherapy of human colon cancer.
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      PubDate: 2015-07-02T06:07:37Z
       
  • Determination of the structure of the O-antigen and the lipid A from the
           entomopathogenic bacterium Pseudomonas entomophila lipopolysaccharide
           along with its immunological properties
    • Abstract: Publication date: 14 August 2015
      Source:Carbohydrate Research, Volume 412
      Author(s): Immacolata Speciale , Ida Paciello , Luigi Lembo Fazio , Luisa Sturiale , Angelo Palmigiano , Rosa Lanzetta , Michelangelo Parrilli , Domenico Garozzo , Bruno Lemaitre , Maria Lina Bernardini , Antonio Molinaro , Cristina De Castro
      The structure and the immunology of the lipopolysaccharide (LPS) of Pseudomonas entomophila, an entomopathogenic bacterium isolated from the fruit fly Drosophila melanogaster, was characterized. The O-antigen portion was established and resulted to be built up of a repetitive unit constituted by four monosaccharide residues, all L configured, all deoxy at C-6 and with an acetamido function at C-2: →3)-α-l-FucNAc-(1→4)-α-l-FucNAc-(1→3)-α-l-FucNAc-(1→3)-β-l-QuiNAc-(1→ The structural analysis of lipid A, showed a mixture of different species. The diphosphorylated glucosamine backbone carries six fatty acids consistent with the composition C10:0 3(OH), C12:0 2(OH) and C12:0 3(OH), whereas other species differs by the number of phosphates and/or of fatty acids. The immunology experiments demonstrated that the LPS structure of P. entomophila displayed a low ability to engage the TLR4-mediated signaling correlated to a significant antagonistic activity toward hexa-acylated LPS structures.
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      PubDate: 2015-07-02T06:07:37Z
       
  • Structure of the O-polysaccharide of Escherichia coli O87
    • Abstract: Publication date: 14 August 2015
      Source:Carbohydrate Research, Volume 412
      Author(s): Evelina L. Zdorovenko , Alla K. Golomidova , Nikolai S. Prokhorov , Alexander S. Shashkov , Lei Wang , Andrei V. Letarov , Yuriy A. Knirel
      The following structure of the O-polysaccharide of Escherichia coli HS1/2 serving as a primary receptor for bacteriophage DT57-12 was elucidated by sugar analysis along with 1D and 2D 1H and 13C NMR spectroscopy: This structure is shared by E. coli O87 type strain. Putatively assigned functions of genes in the O-antigen gene cluster of E. coli O87 are consistent with the O-polysaccharide structure established.
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      PubDate: 2015-07-02T06:07:37Z
       
  • Editorial board
    • Abstract: Publication date: 26 June 2015
      Source:Carbohydrate Research, Volume 411




      PubDate: 2015-07-02T06:07:37Z
       
  • Graphical contents list
    • Abstract: Publication date: 26 June 2015
      Source:Carbohydrate Research, Volume 411




      PubDate: 2015-07-02T06:07:37Z
       
  • Synthesis of spirofused carbohydrate-oxazoline based palladium(II)
           complexes
    • Abstract: Publication date: 26 June 2015
      Source:Carbohydrate Research, Volume 411
      Author(s): Jochen Kraft , Thomas Ziegler
      Four carbohydrate-derived 2-pyridyl and 2-quinolinyl substituted spiro-oxazoline ligands were prepared from 3,4,5-tri-O-benzyl-1,2-di-O-isopropylidene-β-d-fructose in four steps. Conversion of the latter compound with trimethylsilylazide followed by hydrogenation gave an anomeric mixture of 2-amino-3,4,5-tri-O-benzyl-2-deoxy-1-O-trimethylsilyl-d-fructopyranose. Amide coupling of the fructosylamines with picolinic acid and quinaldic acid, respectively afforded the corresponding anomeric amidofructosides, which were both separated and characterized by NMR spectroscopy and X-ray crystallography. Cyclization of alpha-amides was achieved by treatment of the corresponding mesylates with NaH while beta-amides were directly cyclisized with NCS and Ph3P to give the corresponding 2-pyridyl (PyOx) and 2-quinolyl (QuinOx) substituted spiro-oxazoline ligands, respectively. The 2-pyridyl substituted spiro-oxazoline ligands PyOx formed stable complexes with Pd(II), which were fully characterized and their structure determined by X-ray crystallography, whereas the corresponding QuinOx ligands failed to form similar Pd complexes.
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      PubDate: 2015-07-02T06:07:37Z
       
  • Theoretical study on the effects of a 4,6-O-diacetal protecting
           group on the stability of ion pairs from d-mannopyranosyl and
           d-glucopyranosyl triflates
    • Abstract: Publication date: 26 June 2015
      Source:Carbohydrate Research, Volume 411
      Author(s): Takashi Hosoya , Paul Kosma , Thomas Rosenau
      Ion pair formation from 2,3-di-O-methyl-4,6-O-formylidene-α-d-mannopyranosyl triflate αT Man and its d-glucopyranosyl counterpart αT Glc was investigated at the DFT(M06-2X) level of theory, for the purpose of clarifying the effects of the 4,6-tethering on the structure and stability of α- and β-contact ion pairs and solvent-separated ion pairs at −78 °C. In both mannopyranosyl and glucopyranosyl triflates, the 4,6-O-formylidene group destabilized 4H3-type conformers of the α-contact ion pairs, rendering B2,5-types the exclusive conformers for this species. The B2,5-like α-contact ion pair from αT Man was 3.5 kcal/mol more stable than that from αT Glc , probably due to the stabilizing effect by the planar O-5–C-1–C-2–O-2 dihedral angle of the former. This difference in stability of the α-contact ion pair between the mannopyranosyl and glucopyranosyl series gives insights into the mechanisms underlying the reported experimental observation that highly β-selective mannosylation can be achieved with 4,6-O-diacetal mannopyranosyl donors.
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      PubDate: 2015-07-02T06:07:37Z
       
  • Comparing substrate specificity of two UDP-sugar pyrophosphorylases and
           efficient one-pot enzymatic synthesis of UDP-GlcA and UDP-GalA
    • Abstract: Publication date: 26 June 2015
      Source:Carbohydrate Research, Volume 411
      Author(s): Yuxi Guo , Junqiang Fang , Tiehai Li , Xu Li , Cheng Ma , Xuan Wang , Peng G. Wang , Lei Li
      Uridine 5′-diphosphate-glucuronic acid (UDP-GlcA) and UDP-galacturonic acid (UDP-GalA), the unique carboxylic acid-formed sugar nucleotides, are key precursors involved in the biosynthesis of numerous cell components. Limited availability of those components has been hindering the development of efficient ways towards facile synthesis of bioactive glycans such as glycosaminoglycans. In current study, we biochemically characterized two UDP-sugar pyrophosphorylases from Arabidopsis thaliana (AtUSP) and Bifidobacterium infantis ATCC15697 (BiUSP), and compared their activities towards a panel of sugar-1-phosphates and derivatives. Both enzymes showed significant pyrophosphorylation activities towards GlcA-1-phosphate, and AtUSP also exhibited comparable activity towards GalA-1-phosphate. By combining with monosaccharide-1-phosphate kinases, we have developed an efficient and facile one-pot three-enzyme approach to quickly obtain hundreds milligrams of UDP-GlcA and UDP-GalA.
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      PubDate: 2015-07-02T06:07:37Z
       
  • Synthesis of novel poly-hydroxyl functionalized acridine derivatives as
           inhibitors of α-Glucosidase and α-Amylase
    • Abstract: Publication date: 26 June 2015
      Source:Carbohydrate Research, Volume 411
      Author(s): Zahra Toobaei , Reza Yousefi , Farhad Panahi , Sara Shahidpour , Maryam Nourisefat , Mohammad Mahdi Doroodmand , Ali Khalafi-Nezhad
      In this study a novel series of poly-hydroxyl functionalized acridine derivatives (L 1 –L 9 ) was synthesized and their inhibitory activities against α-Glucosidase (α-Gls) and α-Amylase (α-Amy) were evaluated, spectroscopically. The synthetic compounds consist of three different substructures, including a 4-(4-aminophenoxy) phenyl group (R3), an acridine moiety (R2) and a poly-hydroxy chain (R1). The results indicate that among the synthetic compounds, L 5 with a chromeno[3′,4′:5,6]pyrido[2,3-d]pyrimidine moiety demonstrates the highest inhibitory activity against both yeast and rat α-Gls enzymes. Also, L 2 with the thioxo-pyrido[2,3-d:6,5-d′] dipyrimidine moiety plays an important role in the inhibition of yeast α-Gls. In addition, the results may suggest a significant role for the nature of sugar moiety of the synthetic compounds in their inhibitory action against α-Gls. Moreover, in comparison with Acarbose, which is a widely used anti-diabetic drug, these compounds show negligible inhibitory activity against pancreatic α-Amy, which is important in the term of their reduced susceptibility for possible development of the intestinal disturbance side effects. Results of this study may suggest these synthetic compounds as novel molecular templates for construction of potentially anti-diabetic drugs with the ability for more convenient management of postprandial hyperglycemia.
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      PubDate: 2015-07-02T06:07:37Z
       
  • Structural analysis of novel trehalose-based oligosaccharides from
           extremely stress-tolerant ascospores of Neosartorya fischeri (Aspergillus
           fischeri)
    • Abstract: Publication date: 26 June 2015
      Source:Carbohydrate Research, Volume 411
      Author(s): Timon T. Wyatt , Gerrit J. Gerwig , Johannis P. Kamerling , Han A.B. Wösten , Jan Dijksterhuis
      Different fungi, including the genera Neosartorya, Byssochlamys and Talaromyces, produce (asco)spores that survive pasteurization treatments and are regarded as the most stress-resistant eukaryotic cells. Here, the NMR analysis of a series of trehalose-based oligosaccharides, being compatible solutes that are accumulated to high levels in ascospores of the fungus Neosartorya fischeri, is presented. These oligosaccharides consist of an α,α-trehalose backbone, extended with one [α-d-Glcp-(1→6)-α-d-Glcp-(1↔1)-α-d-Glcp; isobemisiose], two [α-d-Glcp-(1→6)-α-d-Glcp-(1→6)-α-d-Glcp-(1↔1)-α-d-Glcp] or three [α-d-Glcp-(1→6)-α-d-Glcp-(1→6)-α-d-Glcp-(1→6)-α-d-Glcp-(1↔1)-α-d-Glcp] glucose units. The tetra- and pentasaccharide, dubbed neosartose and fischerose, respectively, have not been reported before to occur in nature.
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      PubDate: 2015-07-02T06:07:37Z
       
  • Characterization of a novel polysaccharide with anti-colon cancer activity
           from Lactobacillus helveticus MB2-1
    • Abstract: Publication date: 26 June 2015
      Source:Carbohydrate Research, Volume 411
      Author(s): Wei Li , Weizhi Tang , Juan Ji , Xiudong Xia , Xin Rui , Xiaohong Chen , Mei Jiang , Jianzhong Zhou , Mingsheng Dong
      The present study aimed at investigating the potential anti-colon cancer activity of three purified exopolysaccharides fractions (LHEPS-1, LHEPS-2 and LHEPS-3) from the Lactobacillus helveticus MB2-1. The experimental evidence showed that LHEPS-1 significantly inhibited cell proliferation of human colon cancer Caco-2 cells in both time- and concentration-dependent manners. In contrast, no significant improvements of the inhibitory effects of LHEPS-2 and LHEPS-3 on Caco-2 cells were observed with increasing sample concentrations or prolonged incubation time. Furthermore, the structure of LHEPS-1 was elucidated using methylated analysis, gas chromatography–mass spectroscopy (GC–MS) and nuclear magnetic resonance spectroscopy (NMR), including one- and two-dimensional nuclear magnetic resonance (1D and 2D NMR). Results indicated that the LHEPS-1 consisted of a decasaccharide repeating unit with the following structure (n≈122): Our results suggested that the LHEPS-1 produced by L. helveticus MB2-1 might be suitable for using as natural anti-colon cancer drugs and functional foods ingredients.
      Graphical abstract image

      PubDate: 2015-07-02T06:07:37Z
       
  • Isolation and characterization of inulin with a high degree of
           polymerization from roots of Stevia rebaudiana (Bert.) Bertoni
    • Abstract: Publication date: 26 June 2015
      Source:Carbohydrate Research, Volume 411
      Author(s): Sheila M.S. Lopes , Gabriela Krausová , Vojtěch Rada , José E. Gonçalves , Regina A.C. Gonçalves , Arildo J.B. de Oliveira
      The polysaccharide inulin has great importance in the food and pharmaceutical industries. The degree of polymerization (DP) of inulin influences important properties, such as, solubility, thermal stability, sweetness power and prebiotic activity. Molecules with a high degree of polymerization are obtained through physical techniques for enrichment of the inulin chains because they are not commonly obtained from plants extract. Gas chromatography/Mass Spectrometry and 1H Nuclear Magnetic Resonance analysis showed that inulin from Stevia rebaudiana roots has a degree of polymerization (DPn 28) higher than the value of DPn 12–15 for inulins from other plant species. Furthermore, the methodology of freeze/thaw to enrich the chains allowed us to increase the DP, similarly to other methodologies used for the enrichment of inulin chains. The prebiotic assays confirm that inulin from S. rebaudiana has a high DP. The combined use of these molecules with low degree of polymerization fructans seems to be advantageous to prolong the prebiotic effect in the colon. Our results suggest that S. rebaudiana roots are a promising source of high degree polymerization inulins.
      Graphical abstract image

      PubDate: 2015-07-02T06:07:37Z
       
  • A novel rhamno-mannan exopolysaccharide isolated from biofilms of
           Burkholderia multivorans C1576
    • Abstract: Publication date: 26 June 2015
      Source:Carbohydrate Research, Volume 411
      Author(s): Stefania Dolfi , Aris Sveronis , Alba Silipo , Roberto Rizzo , Paola Cescutti
      Burkholderia multivorans C1576 is a Gram negative opportunistic pathogen causing serious lung infection in cystic fibrosis patients. Considering that bacteria naturally form biofilms, and exopolysaccharides are recognized as important factors for biofilm architecture set-up, B. multivorans was grown both in biofilm and in non-biofilm mode on two different media in order to compare the exopolysaccharides biosynthesized in these different experimental conditions. The exopolysaccharides produced were purified and their structure was determined resorting mainly to NMR spectroscopy, ESI mass spectrometry and gas chromatography coupled to mass spectrometry. The experimental data showed that both in biofilm and non-biofilm mode B. multivorans C1576 produced a novel exopolysaccharide having the following structure: About 50% of the 2-linked rhamnose residues are substituted on C-3 with a methyl ether group. The high percentage of deoxysugar Rha units, coupled with OMe substitutions, suggest a possible role for polymer domains with marked hydrophobic characteristics able to create exopolysaccharide junction zones favouring the stability of the biofilm matrix.
      Graphical abstract image

      PubDate: 2015-07-02T06:07:37Z
       
  • Preparation of asparagine-linked monoglucosylated high-mannose-type
           oligosaccharide from egg yolk
    • Abstract: Publication date: 26 June 2015
      Source:Carbohydrate Research, Volume 411
      Author(s): Ning Wang , Akira Seko , Yoichi Takeda , Yukishige Ito
      Monoglucosylated high-mannose-type glycan (Glc1Man9GlcNAc2: G1M9) is well-known as a key glycoform in the glycoprotein folding process, which is specifically recognized by lectin chaperones calnexin (CNX) and calreticulin (CRT) in the endoplasmic reticulum (ER). In this work, we developed an efficient method for the preparation of G1M9-Asn. The G1M9-Asn was obtained from the IgY-rich fraction derived from hen egg yolk by the digestion with pronase. The α-amino group of asparagine in G1M9-Asn was protected with the 9-fluorenylmethyloxycarbonyl (Fmoc) group and the labeled glycans were subsequently purified using high performance liquid chromatography (HPLC). This method will provide useful substrates for analysis of the glycoprotein folding cycle in the ER.
      Graphical abstract image

      PubDate: 2015-07-02T06:07:37Z
       
  • Structure and gene cluster of the O-antigen of Escherichia coli O140
    • Abstract: Publication date: 26 June 2015
      Source:Carbohydrate Research, Volume 411
      Author(s): Andrei V. Perepelov , Quan Wang , Sof'ya N. Senchenkova , Zhu Mei , Alexander S. Shashkov , Lei Wang , Yuriy A. Knirel
      An acidic O-polysaccharide (O-antigen) was isolated from the lipopolysaccharide of Escherichia coli O140 and studied by sugar analysis along with 1D and 2D 1H and 13C NMR spectroscopy. The following structure of the branched hexasaccharide repeating unit was established: The O-antigen gene cluster of E. coli O140 was sequenced. The gene functions were tentatively assigned by a comparison with sequences in the available databases and found to be in full agreement with the E. coli O140 polysaccharide structure.
      Graphical abstract image

      PubDate: 2015-07-02T06:07:37Z
       
  • Modeling of Cooked Starch Digestion Process Using Recombinant Human
           Pancreatic α-Amylase and Maltase-Glucoamylase for in vitro Evaluation
           of α-Glucosidase Inhibitors
    • Abstract: Publication date: Available online 26 June 2015
      Source:Carbohydrate Research
      Author(s): Xiaofang Cao , Chen Zhang , Yangyang Dong , Peng Geng , Fang Bai , Gang Bai
      In human, digestion of cooked starch mainly involves breaking down of α-amylase to α-limit dextrins and small linear malto-oligosaccharides, which are in turn hydrolyzed to glucose by the gut mucosal maltase-glucoamylase (MGAM). Human pancreatic α-amylase (HPA), amino- and carboxyl-terminal portions of MGAM (ntMGAM and ctMGAM) catalyze the hydrolysis of α-D-(1,4) glycosidic linkages in starch, playing a crucial role in the production of glucose in the human lumen. Accordingly, these enzymes are effective drug targets for the treatments of type 2 diabetes and obesity. In this study, a Plackett-Burman based statistical screening procedure was adopted to determine the most critical factors affecting cooked starch digestion by the combination of HPA, ctMGAM and ntMGAM. Six factors were tested and experimental results showed that pH and temperature were the major influencing factors, with optimal pH and temperature at 6.0 and 50°C, respectively. Surprisingly, ntMGAM had no significant contribution to the glucose production from starch digestion compared to the HPA and ctMGAM. The optimal proportion of HPA and ctMGAM in a starch digestion system was further determined by response surface methodology. Results showed a maximum starch digestion (88.05%) within 0.5 hour when used HPA:ctMGAM=1:9 (U). The inhibitory effects of various inhibitors on the cooked starch digestion by HPA1/ctMGAM9 were evaluated by determining their half maximal inhibitory concentration (IC50) values. Acarviostatin II03 showed the highest inhibitory activity, with 67 times higher potency than acarbose. Moreover, acarviostatin II03 could significantly depress postprandial blood glucose levels in mice, better than that by acarbose. These findings suggest that our in vitro enzymatic system can simulate in vivo starch digestion process, and thus can be used to screen and evaluate α-glucosidase inhibitors.
      Graphical abstract image

      PubDate: 2015-07-02T06:07:37Z
       
  • UDP-hexose 4-epimerases: a view on structure, mechanism and substrate
           specificity
    • Abstract: Publication date: Available online 21 June 2015
      Source:Carbohydrate Research
      Author(s): Koen Beerens , Wim Soetaert , Tom Desmet
      UDP-sugar 4-epimerase (GalE) belongs to the short-chain dehydrogenase/reductase (SDR) superfamily of proteins and is one of enzymes in the Leloir pathway. They have been shown to be important virulence factors in a number of Gram-negative pathogens and to be involved in the biosynthesis of different polysaccharide structures. The metabolic disease type III galactosemia is caused by detrimental mutations in the human GalE. GalE and related enzymes display unusual enzymologic, chemical, and stereochemical properties; including irreversible binding of the cofactor NAD and uridine nucleotide-induced activation of this cofactor. These epimerases have been found active on UDP-hexoses, the N-acetylated and uronic acid forms thereof as well as UDP-pentoses. As they are involved in different pathways and functions, a deeper understanding of the enzymes, and their substrate promiscuity and/or selectivity, could lead to drug and vaccine design as well as antibiotic and probiotic development. This review summarizes the research performed on UDP-sugar 4-epimerases’ structure, mechanism and substrate promiscuity.
      Graphical abstract image

      PubDate: 2015-07-02T06:07:37Z
       
  • Structures and biological activities of cladolosides C3, E1, E2, F1, F2,
           G, H1 and H2, eight triterpene glycosides from the sea cucumber Cladolabes
           schmeltzii with one known and four new carbohydrate chains
    • Abstract: Publication date: Available online 20 June 2015
      Source:Carbohydrate Research
      Author(s): Alexandra S. Silchenko , Anatoly I. Kalinovsky , Sergey A. Avilov , Pelageya V. Andryjaschenko , Pavel S. Dmitrenok , Ekaterina A. Yurchenko , Igor Yu. Dolmatov , Vladimir I. Kalinin
      Eight new nonsulfated triterpene glycosides, cladolosides C3 (1), E1 (2), E2 (3), F1 (4), F2 (5), G (6), H1 (7) and H2 (8) have been isolated from the tropical Indo-West Pacific sea cucumber Cladolabes schmeltzii (Cladolabinae, Sclerodactylidae, Dendrochirotida) collected in the Vietnamese shallow waters. The structures of the glycosides were elucidated by 2D NMR spectroscopy and mass-spectrometry. Glycosides 2, 3, 4, and 5 have pentasaccharide branched carbohydrate moieties and differ from each other by monosaccharide compositions and aglycone structures. At that, glycosides 2 and 3 contain three xylose, one 3-O-methyl-glucose and one quinovose residues, while glycosides 4 and 5 have two quinovose, two xylose and one 3-O-methyl-glucose residues. Compounds 1 and 6–8 are hexaosides differing from each other by aglycone structures and by the fifth monosaccharide residue, which proved to be glucose in cladoloside C3 (1), xylose in cladoloside G (6) and quinovose in cladolosides H1 (7) and H2 (8). The presence of quinovose residue in the fifth position, as in 4, 5, 7 and 8 has never been earlier found in carbohydrate chains of triterpene glycosides from sea cucumbers. The carbohydrate chains with xylose in the fifth position of pentaosides and hexaosides are also very unusual for holothurious glycosides. All the substances demonstrate strong or moderate cytotoxic and hemolytic effects with hexaosides being more active than the corresponding pentaosides. Peculiarities of the biosynthesis and biochemical evolution of glycosides of this type are discussed.
      Graphical abstract image

      PubDate: 2015-07-02T06:07:37Z
       
  • Editorial board
    • Abstract: Publication date: 17 June 2015
      Source:Carbohydrate Research, Volume 410




      PubDate: 2015-07-02T06:07:37Z
       
  • Graphical contents list
    • Abstract: Publication date: 17 June 2015
      Source:Carbohydrate Research, Volume 410




      PubDate: 2015-07-02T06:07:37Z
       
 
 
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