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Carbohydrate Research

Ashokkumar Palanivel, Ande Chennaiah, Sateesh Dubbu, Asadulla Mallick, Yashwant D Vankar
Activation of sulfoxide as glycosyl donors using AuCl3/AgOTf reagent system has been described. Under optimal reaction conditions, both armed and disarmed glycosyl sulfoxide donors were found to react with a range of primary, secondary, and tertiary alcohol acceptors, and sugar derived glycosyl acceptors to afford the corresponding glycosides in moderate to good yields with predictable selectivity. The reactions are quick (20-60 min), facile at room temperature and the reactions conditions tolerate acid sensitive groups...
November 23, 2016: Carbohydrate Research
Fatemeh Tamaddon, MohammadTaghi KazemiVarnamkhasti
Preparation, characterization, and application of alkali starch (AS) given by dry co-grinding of starch and alkali is described in this work. Grinding using a mortar (agate) and pestle or, more conveniently, a ball mill has been found to be satisfactory for the preparation of the AS. The AS products were characterized by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) and x-ray fluorescence (XRF) analyses. The base capacities of ASs were 4.25-4.45 mmol/g, respectively...
November 16, 2016: Carbohydrate Research
Magdolna Csávás, Lenka Malinovská, Florent Perret, Milán Gyurkó, Zita Tünde Illyés, Michaela Wimmerová, Anikó Borbás
The opportunistic Gram-negative bacterium Burkholderia cenocepacia causes lethal infections in cystic fibrosis patients. Multivalent mannoside derivatives were prepared as potential inhibitors of lectin BC2L-A, one of the virulence factors deployed by B. cenocepacia in the infection process. An (α1→2)-thio-linked mannobioside mimic bearing an azide functionalized aglycon was conjugated to different multivalent scaffolds such as propargylated calix[4]arenes, methyl gallate and pentaerythritol by azide-alkyne 1,3-dipolar cycloaddition...
November 14, 2016: Carbohydrate Research
Leonid O Kononov, Ksenia G Fedina, Anna V Orlova, Nikolay N Kondakov, Polina I Abronina, Nikita M Podvalnyy, Alexander O Chizhov
Changes in concentration (0.001-0.1 M) of an arabinofuranosyl donor (1) have been shown to modulate the temperature T at which activation of 1 occurs (from -23 °C to +7 °C), the reaction time (from 1.5 h to 3 days) and the yield of the disaccharide formed (from 14% to 82%). At concentrations exceeding 0.01 M, these parameters, as well as the specific optical rotation of the solution of 1, virtually do not depend on concentration suggesting formation of reacting species (supramers) of glycosyl donor with similar structures, hence reactivities, but considerably different from those formed in more dilute solutions...
November 12, 2016: Carbohydrate Research
Dorothy L Ackerman, Kelly M Craft, Steven D Townsend
Professional health bodies such as the World Health Organization (WHO), the American Academy of Pediatrics (AAP), and the U.S. Department of Health and Human Services (HHS) recommend breast milk as the sole source of food during the first year of life. This position recognizes human milk as being uniquely suited for infant nutrition. Nonetheless, most neonates in the West are fed alternatives by 6 months of age. Although inferior to human milk in most aspects, infant formulas are able to promote effective growth and development...
November 11, 2016: Carbohydrate Research
Mohsin O Mohammed, Juma'a R Al Dulayymi, Mark S Baird
An efficient synthetic approach to tri-arabino di-mycolates, using structurally defined synthetic α-, keto and methoxy mycolic acids is described.
November 10, 2016: Carbohydrate Research
Claudia Puchner, Thomas Eixelsberger, Bernd Nidetzky, Lothar Brecker
Human UDP-xylose synthase (hUXS1) exclusively converts UDP-glucuronic acid to UDP-xylose via intermediate UDP-4-keto-xylose (UDP-Xyl-4O). Synthesis of model compounds like methyl-4-keto-xylose (Me-Xyl-4O) is reported to investigate the binding pattern thereof to hUXS1. Hence, selective oxidation of the desired hydroxyl function required employment of protecting group chemistry. Solution behavior of synthesized keto-saccharides was studied without enzyme via (1)H and (13)C NMR spectroscopy with respect to existent forms in deuterated potassium phosphate buffer...
November 5, 2016: Carbohydrate Research
Lei Chen, Changjiang Yu, Yubin Ma, Hua Xu, Shumin Wang, Yu Wang, Xingxun Liu, Gongke Zhou
The structure and physicochemical properties of starches from two hydrophyte duckweeds, Spirodela oligorrhiza and Lemna minor, were investigated and compared in this study. The amylose content and average size of starches were determined to be 20.85%, 4.70 μm and 27.77%, 6.17 μm for Spirodela oligorrhiza and Lemna minor, respectively. The average chain length of two duckweed starches was measured to be around DP 28. The chain length distribution was observed to be greatly different from other reported starches for the high proportion of long chains (DP ≥ 37) over 50%...
October 26, 2016: Carbohydrate Research
D Mangan, A Liadova, R Ivory, B V McCleary
We report herein the development of a novel assay procedure for the measurement of β-glucanase and lichenase (EC in crude enzyme extracts. Two assay formats based on a) a direct cleavage or b) an enzyme coupled substrate were initially investigated. The 'direct cleavage' substrate, namely 4,6-O-benzylidene-2-chloro-4-nitrophenyl-β-3(1)-cellotriosyl-β-glucopyranoside (MBG4), was found to be the more generally applicable reagent. This substrate was fully characterised using a crude malt β-glucanase extract, a bacterial lichenase (Bacillus sp...
October 20, 2016: Carbohydrate Research
Bin Liu, Jiaojiao Lu, Chunqing Ai, Bao Zhang, Li Guo, Shuang Song, Beiwei Zhu
Uronic acid-containing polysaccharides (UACPs) including well-known glycosaminoglycans (GAGs) and some non-GAGs exist widely in animal kingdom. Although numerous methods have been established to analyze GAGs, few methods are available for non-GAG UACPs. In the present study, a protocol to identify all kinds of UACPs with repeating disaccharide units of hexosamine and uronic acid was demonstrated, and UACP components in five shellfishes, namely Turritella fortilirata Sowerby (GTF), Batillaria zonalis (GBZ), Nassarius variciferus (GNV), Monodonta labio Linnaeus (GML), and Argopecten irradians Lamarck (BAI) were primarily revealed...
October 11, 2016: Carbohydrate Research
Julie Barbeau, Loïc Lemiègre, Allan Quelen, Virginie Malard, Haifei Gao, Cristine Gonçalves, Mathieu Berchel, Paul-Alain Jaffrès, Chantal Pichon, Patrick Midoux, Thierry Benvegnu
An archaeal diether lipid possessing a tri-antenna of α-D-mannopyranoside linked via an oligoethylene spacer to a (2S)-2-(phytanyloxy)-3-(hexadecyloxy)propanoic acid backbone (TriMan-Diether) was designed and synthesized. This new mannosylated lipid inserted in liposomes would show both DC-targeting and adjuvant properties thanks to the TriMan structure and the diether tail part, respectively.
October 11, 2016: Carbohydrate Research
Evgeny Vinogradov, Irina Sadovskaya, Thierry Grard, Marie-Pierre Chapot-Chartier
Lactobacillus casei is a Gram positive lactic acid bacterium used in dairy fermentations and present in the normal human gut microbiota. Certain strains are recognized as probiotics with beneficial effects on human and animal health. L. casei BL23 is a potential probiotic strain endowed with anti-inflammatory properties and a model strain widely used in genetic, physiological and biochemical studies. A number of bacterial cell surface polysaccharides have been shown to play a role in the immune modulation activities observed for probiotic lactic acid bacteria...
October 8, 2016: Carbohydrate Research
Giuliana Righi, Emanuela Mandic', Carla Sappino, Ergys Dema, Paolo Bovicelli
Herein the total synthesis of the pyrrolidine alkaloids 1,4-dideoxy-1,4-imino-d-galactitol and its diastereoisomer 1,4-dideoxy-1,4-imino-d-glucitol is described, starting from a common optically active precursor. The key step in our approach was the double diastereoselection in the asymmetric dihydroxylation of chiral vinyl azido alcohols, obtained by means of two different regio- and stereoselective nucleophilic openings of the corresponding chiral vinyl epoxide.
October 3, 2016: Carbohydrate Research
Ivan M Ryzhov, Elena Yu Korchagina, Alexander B Tuzikov, Inna S Popova, Tatiana V Tyrtysh, Galina V Pazynina, Stephen M Henry, Nicolai V Bovin
Seven lipophilic constructs containing Lewis (Le(a), Le(b), Le(y)) or chimeric Lewis/ABH (ALe(b), BLe(b), ALe(y), BLe(y)) glycans were obtained starting from corresponding oligosaccharides in form of 3-aminopropyl glycosides. ALe(b) and BLe(b) pentasaccharides were synthesized via [3 + 1] blockwise approach. The constructs (neoglycolipids, or FSLs) were inserted in erythrocyte membrane, and obtained "kodecytes" were used to map the immunochemical specificity of historical and contemporary monoclonal and polyclonal blood group system Lewis reagents...
September 28, 2016: Carbohydrate Research
Yang Yang, Hai-Peng Liu, Qun Yu, Mei-Bing Yang, De-Min Wang, Tian-Wei Jia, Hao-Jie He, Yun He, Hai-Xia Xiao, Suri S Iyer, Zhen-Chuan Fan, Xin Meng, Peng Yu
A new class of S-sialoside Human Serum Albumin (HSA) and Bovine Serum Albumin (BSA) conjugates were prepared to enhance the binding affinity to hemagglutinin (HA) and neuraminidase (NA). The valency of glycoconjugates was controlled by the reaction ratio of the S-sialoside monomer and protein. Hemagglutination inhibition assay showed that these synthetic glycoproteins have higher affinity to HA than the small clusters of sialosides with lower valency, due to multivalent effect and optimized three dimensional presentation of sialosides on the protein platform...
September 28, 2016: Carbohydrate Research
Diogo R B Ducatti, Madison A Carroll, David L Jakeman
A phosphorolytic activity has been reported for beta-N-acetylglucosaminidases from glycoside hydrolase family 3 (GH3) giving an interesting explanation for an unusual histidine as catalytic acid/base residue and suggesting that members from this family may be phosphorylases [J. Biol. Chem. 2015, 290, 4887]. Here, we describe the characterization of Hsero1941, a GH3 beta-N-acetylglucosaminidase from the endophytic nitrogen-fixing bacterium Herbaspirillum seropedicae SmR1. The enzyme has significantly higher activity against pNP-beta-D-GlcNAcp (Km = 0...
September 23, 2016: Carbohydrate Research
Sof'ya N Senchenkova, Xi Guo, Olesya I Naumenko, Alexander S Shashkov, Andrei V Perepelov, Bin Liu, Yuriy A Knirel
O-polysaccharides (OPSs) were obtained by mild acid degradation of the lipopolysaccharides of Escherichia coli O182-O187, and their structures were established by sugar analysis, Smith degradation, and (1)H and (13)C NMR spectroscopy. In addition to the monosaccharides that occur often in E. coli OPSs (d-Glc, d-Gal, d-Man, d-GlcNAc, d-GalNAc, d-GlcA, l-Fuc, d-Rib), a number of less common components were identified as the OPS constituents, including 2-acetamido-2-deoxy-l-quinovose and 4-deoxy-4-[(S)-3-hydroxybutanoyl-l-alanyl]-d-quinovose (O186), 3-acetamido-3-deoxy-d-fucose (O187), 3-deoxy-3-[(R)-3-hydroxybutanoyl]-d-fucose (O184), and 2,3-diacetamido-2,3-dideoxy-l-rhamnose (O182)...
September 23, 2016: Carbohydrate Research
Ethan D Goddard-Borger, Christina Tysoe, Stephen G Withers
Globoid cell leukodystrophy (GCL), or Krabbe disease, is a lysosomal storage disorder characterized by a deficiency in galactosylceramidase (GALC), which hydrolyses galactosylceramide and galactosylsphingosine (psychosine). Early detection of GCL in newborns is essential for timely therapeutic intervention and could be achieved by testing infant blood samples with isotopically labeled lysosmal enzyme substrates and mass spectrometry. While isotopically labeled psychosine would be a useful tool for the early diagnosis of GCL, its synthesis is lengthy and expensive...
September 22, 2016: Carbohydrate Research
Yannick Guinet, Laurent Carpentier, Laurent Paccou, Patrick Derollez, Alain Hédoux
Kinetics of isothermal crystallization of l-arabitol were analyzed from the undercooled liquid state within micron-sized droplets from micro-Raman spectroscopy. This study reveals that crystallization slightly above Tg is controlled by stochastic heterogeneous nucleation inherent to the droplet size. Microscopic Raman investigations performed in droplets give the unique opportunity to analyze the pure metastable Form II of l-arabitol. It was found that Form II is characterized by a molecular packing more compact than that of the stable Form I, inherent to strong intermolecular hydrogen bonding...
September 22, 2016: Carbohydrate Research
Ramu Petakamsetty, Anas Ansari, Ramesh Ramapanicker
A concise organocatalytic route toward the synthesis of furanose and pyranose substituted glycine and alanine derivatives is reported. These compounds are core structural units of some of the naturally available antibiotics and antifungal agents. Proline-catalyzed asymmetric α-amination of aldehydes derived from sugars is used as the key reaction to synthesize twelve sugar amino acid derivatives. The asymmetric transformations proceeded in good yields and with good to excellent diastereoselectivity. The application of the synthesized amino acids is demonstrated by synthesizing a tripeptide containing one of them...
September 21, 2016: Carbohydrate Research
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