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Carbohydrate Research

Jean-Guy Berrin, Marie-Noëlle Rosso, Maher Abou Hachem
Enzymatic degradation of plant biomass is of growing interest for the development of a sustainable bio-based industry. Filamentous fungi, which degrade complex and recalcitrant plant polymers, are proficient secretors of enzymes acting on the lignocellulose composite of plant cell walls in addition to starch, the main carbon storage reservoir. In this review, we focus on the identification of lytic polysaccharide monooxygenases (LPMOs) and their redox partners in fungal secretomes to highlight the biological functions of these remarkable enzyme systems and we discuss future trends related to LPMO-potentiated bioconversion...
May 17, 2017: Carbohydrate Research
Paul N Handley, Anthony Carroll, Vito Ferro
The oligosaccharide phosphate fraction (OPF) obtained from mild acid hydrolysis of P. holstii NRRL Y-2448 phosphomannan is the starting material for the preparation of the Phase III anticancer drug candidate PI-88. The OPF was for the first time successfully separated by preparative ion exchange chromatography and the major oligosaccharides isolated and characterized by NMR spectroscopy. The components were also acetylated and subjected to LC-MS analysis. These studies revealed that the OPF also contained all-α(1 → 3)-linked oligosaccharides in addition to the known α(1 → 3)/(1 → 2)-linked species, most likely formed by hydrolysis of the latter...
May 13, 2017: Carbohydrate Research
Nan Li, Jian Miao, Jing Li, Yu-Ru Zhao, Hong-Mei Li, Yi-Qun Dai, Qiang Huo, Cheng-Zhu Wu, Tao Ma
Corylifol A, a member of the isoflavone subclass of isoflavonoids, has long been considered to have various biological activities. Here, we sought to synthesize corylifol A glucosides by the in vitro glucosylation reaction using the UDP-glycosyltransferase YjiC from Bacillus licheniformis DSM 13, and obtained two novel glucosides: corylifol A-4',7-di-O-beta-d-glucopyranoside (1) and corylifol A-4'-O-beta-d-glucopyranoside (2). To improve the yield of the products, the reaction time, concentration of UDP-glucose, and pH of the buffer were optimized...
May 11, 2017: Carbohydrate Research
Siquan Xu, Lei Zhang, Kehao Xiao, Haian Xia
Herein, the environmentally friendly Fe/β zeolite for glucose isomerization to fructose in aqueous media was reported for the first time. The effects of various reaction conditions including reaction temperature, reaction time, catalyst dosage, etc. on the isomerization reaction over Fe/β zeolite were studied in detail. Under the optimized conditions, yield of fructose higher than 20% were obtained. Moreover, the Fe/β zeolite catalysts were stable and remained constant catalytic activity after five consecutive runs...
May 10, 2017: Carbohydrate Research
Michelle M Kuttel, Zaheer Timol, Neil Ravenscroft
The capsular polysaccharide is the main virulence factor in meningococcus. The capsular polysaccharides for meningococcal serogroups Y and W are almost identical polymers of hexose-sialic acid, suggesting the possibility of cross-protection between group Y and W vaccines. However, early studies indicated that they elicit different levels of cross-protection. Here we explore the conformations of the meningococcal Y and W polysaccharides with molecular dynamics simulations of three repeating unit oligosaccharide strands...
May 10, 2017: Carbohydrate Research
Weilai Guo, Feng Tang, Ken Qin, Mang Zhou, Zhiping Le, Wei Huang
Chemoenzymatic glycoengineering of immunoglobulin G (IgG) catalyzed by Endo-S is a powerful approach to remodel the heterogeneous N-glycoforms of Fc domain with a homogeneous synthetic glycan structure for enhanced Fc receptor-mediated effector functions. The previous researches on the method development mainly focused on human or humanized IgGs with therapeutic potentials. Here, for the first time we report the extended application of this method on glycan-remodeling of serum IgGs from other species including rabbit, mouse, and goat...
May 4, 2017: Carbohydrate Research
Han Zheng, Alexander S Shashkov, Yanwen Xiong, Olesya I Naumenko, Hong Wang, Sof'ya N Senchenkova, Jianping Wang, Yuriy A Knirel
The O-specific polysaccharide (O-antigen) was obtained by mild acid degradation of the lipopolysaccharide of Escherichia albertii serotype O1 strain SP20140089 and studied by sugar analysis along with 1D and 2D (1)H and (13)C NMR spectroscopy. The following structure was established for the trisaccharide repeating unit of the O-polysaccharide: →4)-β-d-ManpNAc3NAcA-(1 → 4)-β-d-GlcpNAm3NAcA-(1 → 3)-α-d-GlcpNAc-(1→ where ManNAc3NAcA and GlcNAm3NAcA indicate 2,3-diacetamido-2,3-dideoxymannuronic acid and 2-acetimidoylamino-3-acetamido-2,3-dideoxyglucuronic acid, respectively...
May 2, 2017: Carbohydrate Research
Duleepa Pathiraja, Kyoung Heon Kim, In-Geol Choi
3,6-Anhydro-L-galactose (L-AHG) is a rare sugar found in agar polysaccharides. L-AHG has been used as a bioactive compound over the past few years. While the chromatographic or mass-spectrometric quantitation of L-AHG is quite sensitive and accurate, these methods require a reference standard and an intensive sample preparation procedure. We developed an enzymatic assay for rapid and robust quantitation of L-AHG using anhydrogalactose dehydrogenase cloned from Vibrio sp. EJY3 (VejAHGD). VejAHGD is a NADP(+) - dependent enzyme which catalyzes the oxidation of L-AHG with a stoichiometric ratio of 1:1...
April 28, 2017: Carbohydrate Research
Xuemeng Mi, Qixin Lou, Wenjing Fan, Liqin Zhuang, You Yang
A gold(I)-catalyzed glycosylation of Kdo with glycosyl ortho-hexynylbenzoate as donor is reported. The couplings of Kdo ortho-hexynylbenzoate with a set of alcohols promoted by PPh3AuOTf afford Kdo glycosides with good β-selectivities. This glycosylation method allows for the synthesis of β-Kdo monosaccharide with a C5 linker at the reducing end for subsequent conjugation to carrier proteins and arrays.
April 28, 2017: Carbohydrate Research
Michael Pröhl, Pascal D Moser, Justyna A Czaplewska, Patrick Hoffmann, Tanja Buś, Anja Traeger, Helmar Goerls, Ulrich S Schubert, Michael Gottschaldt
A pyridyl triazole (pyta) modified sucrose ligand was prepared in a seven step synthesis using d-glucose as the protection group for d-fructose and starting from commercially available sucrose. After complexation with Ru(bpy)2Cl2 precursor, the sucrose-conjugated Ru complex of the general formula [Ru(bpy)2(L)]Cl2 was formed. Acidic cleavage of the d-glucose unit led to the first d-fructose conjugated metal complex viad-fructose C6 in literature. Additionally, pyta-modified d-fructose via C1 and the corresponding Ru complex were synthesized...
April 27, 2017: Carbohydrate Research
Chaolumen Bai, Davaanyam Budragchaa, Takashi Yoshida
New 3-O-branched 1, 6-anhydro glucopyranose disaccharide monomers, 1, 6-anhydro-2, 4-di-O- benzyl-3-O-(2', 3', 4', 6'-tetra-O-benzyl-α-D-mannopyranosyl)- (LGM 6) and -glucopyranosyl)-β-D- glucopyranose (LGG 7), and a trisaccharide monomer, 1, 6-anhydro-2, 4-di-O-benzyl-3-O-α-(2', 3', 6', 2″, 3″, 4″, 6″-hepta-O-benzyl- α-D-maltopyranosyl)-β-D-glucopyranose (LGMAL 8), were synthesized and polymerized. It was found that the 3-O-branched1, 6-anhydro disaccharide monomers were polymerized. However, the polymerizability was lower than that of the 4-O-branched disaccharide monomers reported previously, and the trisaccharide monomer was not polymerizable, probably due to the steric hindrance of the branched bulky mono and disaccharide units at the 3-O position in 1, 6-anhydro glucopyranose...
April 22, 2017: Carbohydrate Research
Shinichiro Tsuchiya, Nobuyuki P Aoki, Daisuke Shinmachi, Masaaki Matsubara, Issaku Yamada, Kiyoko F Aoki-Kinoshita, Hisashi Narimatsu
GlyTouCan version 1.0 was released in 2015 as the international glycan structure repository, and a new sequence format called WURCS (Web3 Unique Representation of Carbohydrate Structures) was proposed during the early stages of the GlyTouCan project. GlyTouCan uses WURCS as its base representation for glycans because existing formats were insufficient in their flexibility to represent any and all glycans universally. Therefore, in order to obtain WURCS strings for existing or new glycan structures, conversion tools or glycan structure editors that can export WURCS became necessary...
April 19, 2017: Carbohydrate Research
Rajesh Kumar, Manish Kumar, Ankita Singh, Neetu Singh, Jyotirmoy Maity, Ashok K Prasad
The synthesis of novel C-4'-spiro-oxetano-α-L-ribonucleosides T and U in 39 and 45% overall yields have been achieved from 2',3',5'-tri-O-acetyl-4'-C-p-toluenesulfonyloxymethyl-β-D-xylofuranosylthymine and 2',3',5'-tri-O-acetyl-4'-C-p-toluenesulfonyloxymethyl-β-D-xylofuranosyluracil, respectively. Both the tosylated nucleoside precursors have been synthesized following recently developed Novozyme(®)-435 catalyzed methodology.
April 19, 2017: Carbohydrate Research
Alexandra S Silchenko, Anatoly I Kalinovsky, Sergey A Avilov, Pelageya V Andryjaschenko, Pavel S Dmitrenok, Ekaterina A Chingizova, Igor Yu Dolmatov, Vladimir I Kalinin
Six new monosulfated triterpene glycosides, cladolosides I1 (1), I2 (2), J1 (3), K1 (4), K2 (5) and L1 (6) were isolated from the tropical Indo-West Pacific sea cucumber Cladolabes schmeltzii (Cladolabinae, Sclerodactylidae, Dendrochirotida). Structures of these glycosides were elucidated by 2D NMR spectroscopy and mass spectrometry. Four new types of carbohydrate chains have been found in 1-6. Cladolosides of the groups I and J are characterized by pentasaccharide carbohydrate chains sulfated at a terminal 3-O-methylglucose residue and branched by the position 4 of the first xylose residue, but differing from each other in the lengths of the main and side carbohydrate chains...
April 19, 2017: Carbohydrate Research
O V Sizova, A N Kondakova, A S Shashkov, Y A Knirel, R Z Shaikhutdinova, S A Ivanov, M E Platonov, M R H Hurst, S V Dentovskaya
An O-polysaccharide was isolated from the lipopolysaccharide of an entomopathogenic bacterium Yersinia entomophaga MH96(T) by mild acid hydrolysis and studied by 2D NMR spectroscopy. The following structure of the branched tetrasaccharide repeating unit of the polysaccharide was established: where Tyv indicates 3,6-dideoxy-d-arabino-hexose (tyvelose). The structure established is consistent with the gene content of the O-antigen gene cluster. The O-polysaccharide structure and gene cluster of Y. entomophaga are related to those of some Y...
April 15, 2017: Carbohydrate Research
U Min Seo, Duc Hung Nguyen, Bing Tian Zhao, Byung Sun Min, Mi Hee Woo
Two new flavanonol glucoside isomers, (2R,3S)-dihydrokaempferol 3-O-β-D-glucoside (1) and (2S,3R)-dihydrokaempferol 3-O-β-D-glucoside (2), were isolated from the aerial parts of Agrimonia pilosa Ledeb., along with eight known flavanonol glucosides (3-10). Their structures were determined on the basis of spectroscopic analysis. In addition, these compounds were evaluated to determine their acetylcholinesterase inhibitory activities. The results indicated that these compounds have moderate inhibitory effects, with IC50 values ranging from 76...
April 15, 2017: Carbohydrate Research
Thomas Zweckmair, Sonja Schiehser, Thomas Rosenau, Antje Potthast
A novel method for the precise and accurate quantification of wood monosaccharides by gas-chromatography mass-spectrometry in complex lignocellulosic biomass matrices is presented. Instead of using the syn- or the anti-peak obtained by blocking the anomeric center using e.g. oximation, the sum of each syn- and anti-peak pair is used for quantification rendering the approach of the apparently constant syn- and anti-peak area ratio. Each wood monosaccharide syn- and anti-peak could essentially be distinguished upon O-ethoximation followed by trifluoroacetylation and separation on a 14% cyanopropyl/phenyl- 86% dimethylpoly-siloxane column...
April 13, 2017: Carbohydrate Research
Robert-Jan van Putten, Jan C van der Waal, Ed de Jong, Hero J Heeres
The conversion of the four possible ketohexoses (fructose, tagatose, sorbose and psicose) into 5-hydroxymethylfurfural (HMF) was explored in water using sulphuric acid as the catalyst (33 mM H2SO4, 120 °C). Significant differences in reactivity were observed and tagatose (48% conversion after 75 min) and psicose (35% conversion after 75 min) were clearly more reactive than fructose and sorbose (around 20% conversion after 75 min). The selectivity to HMF was found to be higher for fructose and psicose than for tagatose and sorbose...
April 13, 2017: Carbohydrate Research
Nicolas Lenfant, Matthieu Hainaut, Nicolas Terrapon, Elodie Drula, Vincent Lombard, Bernard Henrissat
Lytic polysaccharide monooxygenases of family AA9 catalyze the oxidative cleavage of glycosidic bonds in cellulose and related polysaccharides. The N-terminal half of AA9 LPMOs displays a huge sequence variability that is in contradiction with the substrate simplicity so far observed for these enzymes. To understand the cause of the high multigenicity that prevails in the family, we have performed a clustering analysis of the N-terminal region of 3400 sequences of family AA9 LPMOs, and have evaluated the coincidence of the clusters with distal visible features that may accompany functional differences...
April 13, 2017: Carbohydrate Research
Nicolas Petry, Timothé Vucko, Charlotte Collet, Sandrine Lamandé-Langle, Nadia Pellegrini-Moïse, Françoise Chrétien
α- and β-C-allylglucopyranosides and hydroxy-, bromo- and azido-derivatives were prepared through allylation at C-1 of methyl 2,3,4,6-tetra-O-benzyl-D-glucopyranoside or 1-O-acetyl-2,3,4,6-tetra-O-benzyl-D-glucopyranose and subsequent chemical modifications of the alkene on the anomeric arm. However, we picked out some discordance between some recent published studies and our results. After a thorough work of characterization and NMR analysis, we unambiguously confirmed α and β stereochemistry of the two series of compounds and fully described for the first time β-C-propyl alcohol, bromide and azide of 2,3,4,6-tetra-O-benzyl-D-glucopyranose...
April 12, 2017: Carbohydrate Research
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