Carbohydrate Research最新文献

The synthesis of starch grafted with poly (hexafluorobutyl methacrylate) (PHFBMA) was achieved using the horseradish peroxidase (HRP)/acetophenone (ACAC) green initiating system. The modified starch was characterized through FT-IR, ¹⁹F NMR, XPS and EDS to confirm the successful grafting of PHFBMA onto starch backbone. The SEM analysis revealed that the introduction of PHFBMA led to a partial disruption of the crystalline structure of starch, suggesting that PHFBMA did not undergo physical adsorption onto starch. Compared to natural starch film, the modified starch film displays a significantly enhanced hydrophobicity, which can lead to substantial improvements in both the hydrophobicity and tensile properties when applied to hydrophilic paper substrates.

We previously prepared self-reinforced chitin composite (SR-ChC) films, also called all-chitin composites, comprising two components, that is, scale-down chitin nanofibers (SD-ChNFs) with high crystallinity and scale-down low-crystalline chitin (SD-LC-Ch) matrixes. In this study, we precisely evaluated hydrophilicity under water enviromental conditions and its effect on cell adhesion using human-derived cancer cells on the SR-ChC film surfaces. The surface analysis of the SR-ChC films with reduced crystallinity revealed reorientation of the molecular chain assemblies with amino groups in the SD-LC-Ch components in water. Consequently, the amount of the SD-LC-Ch components gave rise to increasing the number of hydrophilic amino groups on the film surfaces, which resulted in efficiency of cell adhesion and elongation. This study concludes that the hydrophilic SD-LC-Ch components in the lower crystalline SR-ChC films strongly contribute to exhibiting new functions, related to interaction with biological substrates, such as cells. © 2017 ElsevierInc.Allrightsreserved.

Moraxella lincolnii is a Gram-negative bacterium that resides in the upper respiratory tract (URT) of humans and may have a role as a member of a protective microbial community. Structural characterisation studies of its outer membrane glycan structures are very limited. We report here the isolation and structural characterisation (NMR, GLC-MS) of a capsular polysaccharide (CPS) and an oligosaccharide (OS) (lipooligosaccharide (LOS)-derived) isolated from strain CCUG 52988. The repeat disaccharide unit of the isolated CPS is unmodified heparosan: [→4)-β-D-GlcpA-(1→4)-α-D-GlcpNAc-(1→]_n, a glycosaminoglycan (GAG) also present in mammalian hosts. The core OS isolated was identified as a branched tetrasaccharide composed of: β-D-Glcp-(1→4)-[β-D-Glcp-(1→6)]-α-D-Glcp-(1→5)-α-Kdo-OH. This core OS structure is without heptose residues and is consistent with previously reported core OS structures from Moraxella spp. Genes encoding homologues of the Lgt6 and Lgt3 glycosyltransferases that catalyse these additions were identified in the genome. Additional glycosyltransferases and other proteins encoded downstream of lgt3 were considered to form the LOS biosynthesis locus. This is the first report of the isolation of CPS and core OS from M. lincolnii.

A total chemical synthesis of spacer-armed Forssman pentasaccharide is reported. The choice of the 2(donor) + 3(acceptor) block scheme, the optimal combination of a limited number of simple protecting groups and the sequence of deprotection steps allowed to achieve the high yield and stereoselectivity of glycosylation and to avoid losses during deprotection. The target pentasaccharide was obtained in a 10-mg scale. ¹H and ¹³C NMR spectra of the Forssman pentasaccharide were completely assigned with the use of various 2D-NMR experiments.

Pectate lyases, known for their alkaliphilic nature, are ideal for industrial applications that require specific pH conditions, particularly in industries such as textiles and pulp extraction. These enzymes, primarily from the polysaccharide lyase family 1 (PL1) of different microbial sources, play a vital role in polysaccharide degradation. Given the potent pectinolytic activity of Bacillus pectate lyases, targeting these enzymes is crucial for identifying the most effective candidates. To address challenges in enzyme selection, we examined the initial catalytic interactions of Bacillus species N16-5 (sp_N16-5), Bacillus species TS-47 (sp_TS-47), and Bacillus species subtilis strain 168 (sub_168) with pectin using molecular docking, focusing on the binding of pectin to the active-site tunnel region. We employed steered molecular dynamics simulations to analyze the disassociation period of pectin, where sp_N16-5 demonstrated higher compactness and we applied a semi-empirical quantum mechanical approach for reaction modeling. Our analysis through NPT ensemble-based dynamics analysis emphasised the structural stability and compactness required to withstand high-production conditions. We identified Bacillus species N16-5 (sp_N16-5) as the most efficient pectinolytic lyase, as it showed strong affinity, reactivity and higher interaction, also sp_N16-5 shows its enthalpy of reaction at 9 kcal/mol with a lower activation energy barrier at 27 kcal/mol which is closest to the typical range among the chosen Bacillus pectate lyase, enabling rapid pectin conversion alongside low energy input. Outcomes from the pH-dependent molecular dynamics revealed the sp_N16-5 to possess a greater structural endurability, comparatively, this study streamlines the screening process for selecting optimal Bacillus pectate lyases through in-silico investigation for industrial applications.

Synthesis of the tetrasaccharide repeating unit of the O-polysaccharide from Halomonas fontilapidosi KR26 was accomplished through a convergent [2 + 2]-block strategy using rationally protected monosaccharide synthons derived from commercially available sugars. The target tetrasaccharide was synthesized in the form of its 2-azidoethyl glycoside to ensure further conjugation with specific aglycons without hampering the reducing end stereochemistry. Use of only acyl/aryl protecting groups was targeted to keep the terminal azido-group intact for the utilization of "Click chemistry" for further conjugations.

The research focuses on the characterization and evaluation of drug delivery efficiency of a microwave-assisted, free-radical synthesized polyacrylamide-grafted Assam Bora rice starch (ABRS) graft copolymer (ABRS-g-PAM). Percentage grafting efficiency (% GE) and intrinsic viscosity were chosen as the optimization parameters. The optimized ABRS-g-PAM Grade Formulation 4 (GF4) was found to be the best grade. GF4 was characterized through XRD, FTIR, TGA, DSC, and ¹³C NMR, confirming efficient polyacrylamide grafting onto ABRS, besides swelling studies. SEM and FESEM showed a rough GF4 surface. Further analysis using Atomic Force Microscopy (AFM) detailed the irregular, rough internal architecture. The maximum swelling of GF4 occurred at pH 7 and 0.005 (M) NaCl, demonstrating second-order swelling kinetics. The soil biodegradability study of GF4 confirmed its biocompatibility. In vitro drug release studies showed that GF4 achieved 99 % release of Rosuvastatin over 26 h, thereby supporting the controlled release behaviour of the optimized polymer.

The members of a widespread Aspergillus fungi genus cause various diseases including the invasive aspergillosis with high morbidity and mortality rates, especially for immunosuppressed patients. One of the main carbohydrate structures on the surface of their cell wall is the galactomannan (GM) which is used in diagnostic kits for the detection of specific types of aspergillosis. However, limited specificity of currently available test systems urges the need for their further improvement. Herein we report the first synthesis of branched heterosaccharides related to GM and containing α-(1→2)-/α-(1→6)-linked tetramannoside backbone chain bearing one galactofuranoside unit or its β-(1→5)-linked dimer. The preparation of conjugates of the obtained spacered oligosaccharides with BSA is also performed to produce tools for the assessment the specificity of anti-Aspergillus immune response and to select antibodies suitable for the development of novel diagnostic kits that may discriminate distinct types of aspergillosis.

Marine sulfated polysaccharides constitute a class of bioactive polymers commonly found in cell walls of macroalgae. Among these macromolecular substances, fucoidans, ulvans, and carrageenans have attracted considerable attention providing interesting therapeutic properties affected by a combination of various structural factors, such as sulfation pattern, molecular weight, monosaccharide composition, and glycosidic linkages. Remarkably, chemical modification, enzymatic hydrolysis and crosslinking are promising approaches for developing the application of these polysaccharides through enhancement and/or addition of new biological properties. This paper reviews the recent advances on these structure modification methods on fucoidans, ulvans, and carrageenans. The physical, chemical and biological properties influenced by the addition of functional groups are also discussed. In addition, an overview of specific enzymes selectively producing oligosaccharides with improved bioactivities as well as ionic and covalent cross-linking strategies are provided. These targeted methods have the potential to develop novel compounds with outstanding biodegradability and biocompatibility, along with low toxicity suitable for diverse applications in biomedical fields, including drug delivery.

The discovery of branched molecules like dextrin by Schardinger in 1903 marked the inception of cyclodextrin (CD) utilization, catalyzing its journey from laboratory experimentation to widespread commercialization within the pharmaceutical industry. CD, a cyclic oligosaccharide containing glucopyranose units, acts as a versatile guest molecule, forming inclusion complexes (ICs) with various host molecules. Computational studies have become instrumental in elucidating the intricate interactions between β-CD and guest molecules, enabling the prediction of binding energy, forces, affinity, and complex stability. The computational approach has established robust correlations with experimental outcomes, enhancing our understanding of CD-mediated complexation phenomena. This comprehensive review delves into the CD based Inclusion complex (CDIC) formation and a myriad of components, including drug molecules, amino acids, vitamins, and volatile oils. These complexes find applications across diverse industries, ranging from pharmaceuticals to nutraceuticals, food, fragrance, and beyond. In the pharmaceutical realm, β- CDICs offer innovative solutions for enhancing drug solubility, stability, and bioavailability, thus overcoming formulation challenges associated with poorly water-soluble drugs. Furthermore, the versatility of CDs extends beyond pharmaceuticals, with applications in the encapsulation of phytoactive compounds in nutraceuticals and the enhancing flavor, aroma in food and fragrance industries. This review underscores the pivotal role of CDs conjugation in modern drug delivery systems, emphasizing the importance of interdisciplinary approaches that integrate computational modeling with experimental validation. As the pharmaceutical landscape continues to evolve, CDs-based formulations stand poised to drive innovation and address the ever-growing demand for efficacious and patient-friendly drug delivery solutions.