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Carbohydrate Research

Iwona Komaniecka, Adam Choma, Katarzyna Zamlynska, Anna Sroka-Bartnicka, Pawel Sowinski
Oligotropha carboxidovorans strain OM5 (previously known as Pseudomonas carboxydovorans OM5) is a rod-shaped Gram-negative bacterium isolated from wastewater. This bacterium is able to live in aerobic and, facultatively, in autotrophic conditions. For autotrophic growth, the bacteria can utilize carbon monoxide or hydrogen as a source of energy. The O-specific polysaccharide isolated from O. carboxidovorans OM5 lipopolysaccharide was structurally characterized using chemical analyses, 1D and 2D NMR spectroscopy, and MALDI-TOF mass spectrometry techniques...
January 3, 2017: Carbohydrate Research
Kiichiro Totani, Kenta Yamaya, Makoto Hirano, Yukishige Ito
Glycoprotein N-linked oligosaccharides in the endoplasmic reticulum function as tags to regulate glycoprotein folding, sorting, secretion and degradation. Since the N-glycan structure of a glycoprotein should reflect the folding state, N-glycan processing may be affected by the aglycone state. In this study, we examined the influence of aglycone structures on N-glycan processing using synthetic substrates. We prepared (Glc1)Man9GlcNAc2 linked to hydrophobic BODIPY-dye with a systematic series of different linker lengths...
December 29, 2016: Carbohydrate Research
Katarzyna Pakiet, Anna Turska-Szewczuk, Magdalena A Karas, Agnieszka Pekala, Hubert Pietras
The O-specific polysaccharide (OPS) was isolated from the lipopolysaccharide of Aeromonas hydrophila strain K691 and studied by chemical methods and (1)H and (13)C NMR spectroscopy, including 2D (1)H,(1)H COSY, TOCSY, NOESY, (1)H-detected heteronuclear (1)H,(13)C HSQC, and HMBC experiments. It was found that the O-specific polysaccharide was built up of pentasaccharide repeating units composed of β-GlcpNAc, 2-O-acetylated α-Rhap, and β-Quip4NAc residues. The following structure of the OPS was established: →3)-α-l-Rha2OAc-(1→3)-β-d-GlcNAc-(1→3)-α-l-Rha2OAc-(1→3)-β-d-GlcNAc-(1→2)-β-d-Qui4NAc-(1→...
December 23, 2016: Carbohydrate Research
Yasaman Ramazani, Elena N Levtchenko, Lambertus Van Den Heuvel, Ann Van Schepdael, Prasanta Paul, Ekaterina A Ivanova, Anna Pastore, Trina M Hartman, Neil P J Price
Cystinosis is a genetic disorder caused by malfunction of cystinosin and is characterized by accumulation of cystine. Cysteamine, the medication used in cystinosis, causes halitosis resulting in poor patient compliance. Halitosis is mainly caused by the formation of dimethylsulfide as the final product in the cysteamine metabolism pathway. We have synthesized carbohydrate-cysteamine thiazolidines, and hypothesized that the hydrolytic breakdown of cysteamine-thiazolidines can result in free cysteamine being released in target organs...
December 18, 2016: Carbohydrate Research
Madeleine K Adam, Yingxue Hu, Jessica S Poisson, Matthew J Pottage, Robert N Ben, Brendan L Wilkinson
Cryopreservation is an important technique employed for the storage and preservation of biological tissues and cells. The limited effectiveness and significant toxicity of conventionally-used cryoprotectants, such as DMSO, have prompted efforts toward the rational design of less toxic alternatives, including carbohydrate-based surfactants. In this paper, we report the modular synthesis and ice recrystallization inhibition (IRI) activity of a library of variably substituted, carbohydrate-based fluorosurfactants...
December 14, 2016: Carbohydrate Research
Rob Field
No abstract text is available yet for this article.
January 13, 2017: Carbohydrate Research
Ashley Hughes, Maria Meneghetti, Teng-Yi Huang, Shang-Cheng Hung, Stefano Elli, Marco Guerrini, Timothy Rudd, Marcelo Lima, Edwin Yates
Glycosaminoglycans such as heparan sulfate (HS) are major components of the cell surface and extracellular matrix (ECM) of all multicellular animals, connecting cells to each other as well as to their environment. The ECM must, therefore, both sense and accommodate changes to external conditions. Heparin, a model compound for HS, responds to increased temperatures, involving changes in the populations of conformational states with implications for the binding of HS to proteins, cations and, potentially, for its activity...
January 13, 2017: Carbohydrate Research
Michał Kowalski, Sławomir Jarosz
2,3,3',4,4'-Penta-O-benzylsucrose was converted into the corresponding diaminoalcohol which was used as a key building block in the synthesis of the analogues of aza-crown ethers and bis-lactams.
January 13, 2017: Carbohydrate Research
Dawa Tsering, Congcong Chen, Jinfeng Ye, Zhipeng Han, Bai-Qian Jing, Xian-Wei Liu, Xi Chen, Fengshan Wang, Peixue Ling, Hongzhi Cao
The enzymatic synthesis of biologically important and structurally unique human P1PK blood group type P1 pentasaccharide antigen is described. This synthesis features a three-step sequential one-pot multienzyme (OPME) glycosylation for the stepwise enzymatic chain elongation of readily available lactoside acceptor with cheap and commercially available galactose and N-acetylglucosamine as donor precursors. This enzymatic synthesis provides an operationally simple approach to access P1 pentasaccharide and its structurally related Gb3 and P1 trisaccharide epitopes...
January 13, 2017: Carbohydrate Research
Irina M Ivanova, Sergey A Nepogodiev, Gerhard Saalbach, Ellis C O'Neill, Michael D Urbaniak, Michael A J Ferguson, Sudagar S Gurcha, Gurdyal S Besra, Robert A Field
Synthetic hexynyl α-D-mannopyranoside and its α-1,6-linked disaccharide counterpart were fluorescently labelled through CuAAC click chemistry with 3-azido-7-hydroxycoumarin. The resulting triazolyl-coumarin adducts, which were amenable to analysis by TLC, HPLC and mass spectrometry, proved to be acceptor substrates for α-1,6-ManT activities in mycobacterial membranes, as well as α- and β-GalT activities in trypanosomal membranes, benchmarking the potential of the fluorescent acceptor approach against earlier radiochemical assays...
January 13, 2017: Carbohydrate Research
Andreas Rathjens, Joachim Thiem
2, 3-Di-ω-halo- as well as 2, 3-di-ω-toluenesulfonamide-alkylated glucopyranoside derivatives were prepared. Their condensation with α,ω-bis-toluenesulfonamide components under varying Richman-Atkins conditions with alkali carbonate in DMF led to carbohydrate-linked aza-macrocycles displaying 14-, 17-, 18-, 21-, 24-, and 25-membered ring structures. Isomeric aza-macrocylic coronands of 20- as well as 30-membered ring size containing two saccharides could be obtained employing Richman-Atkins condensations of two functionalized sugar building units...
January 13, 2017: Carbohydrate Research
Dmitry Z Vinnitskiy, Nadezhda E Ustyuzhanina, Andrey S Dmitrenok, Alexander S Shashkov, Nikolay E Nifantiev
Unsubstituted and 6-O-α-L-fucosylated propyl 2-acetamido-2-deoxy-β-D-galactopyranosides and their selectively O-sulfated (both in GalNAc and Fuc units) derivatives were synthesized as model compounds representing the fragments of fucosylated chondroitin sulfates (FCS) from sea cucumbers. Per-O-acetylated 2-deoxy-2-N-phthalimido-D-glucopyranose was used as a key precursor for the preparation of all 2-acetamido-2-deoxy-D-galactopyranoside containing products. Attempts at 6-O-glycosylation of propyl 3-O-benzoyl-2-deoxy-2-N-phthalimido-D-galactoside by 2-O-benzyl-3,4-di-O-chloracetyl-L-fucosyl trichloracetimidate in the presence of TMSOTf gave a 1:1 mixture of the corresponding α- and β-isomeric disaccharides, while the use of structurally related fucosyl bromide donor with promotion by Bu4NBr led to the formation of desired α-isomeric disaccharide exclusively...
January 13, 2017: Carbohydrate Research
Ashutosh K Dash, Tatina Madhubabu, Syed Khalid Yousuf, Sushil Raina, Debaraj Mukherjee
One-pot carbon-Ferrier rearrangement of glycals with unactivated aryl methyl ketones has been developed under mild Silyl triflate catalysis. Keto methyl group of various aryl methyl ketones without being converted into silyl enol ether could directly attack anomeric position of glycals to form keto functionalized C-glycosides in moderate to good yields with high α-selectivity. The versatility of this method has been extended to the synthesis of a small library of chromanone 3-C-glycosides.
January 13, 2017: 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...
January 2, 2017: 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...
January 2, 2017: 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.
January 2, 2017: 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...
January 2, 2017: 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...
January 2, 2017: 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...
January 2, 2017: 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...
January 2, 2017: Carbohydrate Research
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