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[en] The methods of isolation of fucoidans and determination of their chemical structures are reviewed. The fucoidans represent sulfated polysaccharides of brown algae, the composition of which varies from simple fucan sulfates to complex heteropolysaccharides. The currently known structures of such biopolymers are presented. A variety of the biological activities of fucoidans is briefly summarised.
[en] Mushrooms contain abundant of bioactive compound (polysaccharides and protein) which have benefit to health include immunomodulatory, anticancer, antioxidant and hypocholesterolemic effect. In this study, Pleurotus flabellatus was produced in submerged culture fermentation (SCF) due to its ability to be produced at higher quantity in a compact space and shorter period compared to the conventional method using solid state fermentation. P. flabellatus mycelium were extracted by hot-water extraction method which included boiling with hot water, addition of ethanol, followed by refrigerated centrifuge and lyophilization. The yield of P. flabellatus polysaccharides was 0.95 %. (author)
[en] A procedure to obtain the parameters of the constitutive equations used to describe the shear-thinning behaviour of polysaccharides is presented. It is shown that the existence or not of a master log viscosity-log shear rate curve, for all concentrations, is independent from the constitutive equation used to describe the data. Once the master curve is constructed it can be used to obtain the parameter of the constitutive equation with a higher accuracy, since the experimental range is extended. Some application to experimental data on polysaccharides, reported in the literature, are presented. A fitting procedure to usual constitutive equations is given based on the master curve and on its first derivative. Finally, the applicability of a method proposed recently in the literature, to obtain the parameters of a constitutive equation for polysaccharides, is discussed in detail. (author). 10 refs, 10 figs, 2 tabs
[en] The review addresses the application of synthetic oligosaccharides related to fragments of capsular polysaccharides from different serotypes of the bacterium Streptococcus pneumoniae for the design of third-generation pneumococcal conjugate vaccines. Special focus is given to characteristic features of the chemical structures of oligosaccharides required for the induction of the protective immune response when using synthetic glycoconjugate vaccines based on oligosaccharide ligands and carrier proteins. The bibliography includes 101 references
[en] Nuclear Magnetic Resonance has become the choice for structural studies, identity assays and simultaneous quantification of active pharmaceutical ingredient of different polysaccharide-based vaccine. In the last two decades, the application of quantitative Nuclear Magnetic Resonance had an increasing impact to support several quantification necessities. The technique involves experiments with several modified parameters in order to obtain spectra with quantifiable signals. The present review is supported by some recent relevant reports and it discusses several applications of NMR in carbohydrate-based vaccines. Moreover, it emphasizes and describes several parameters and applications of quantitative Nuclear Magnetic Resonance
[en] The use of nitroxide radicals in the selective oxidation of alcohols is considered. Attention is focused on the oxidation of polysaccharides as a method of preparation of polyuronic acids, aldehydes and hemiacetals.
[en] Biopolymers are studied extensively due to its wide applications in the field of bio-technology, micro fluidics and lab on chip devices. Chitosan is natural biopolymer derived from chitin. It has wide applications in bio-medical engineering because of its biocompatibility and biodegradability. Also, chitosan act as reducing and stabilizing agent for the metal ions. Chitosan is also a good candidate in batteries as membranes. It is therefore important to study the conformational changes of chitosan. In this research work, we used SANS to understand the modifications in the radius of gyration (Rg) values of chitosan polymer in solution and in presence of HAuCl4 and LiClO4. Chitosan solution became a gel in the presence of HAuCl4 enabling to study the associated conformational change in chitosan in gels. We have also made films of chitosan, chitosan- Au and Chitosan- LiClO4 and studied the associated conformational changes in chitosan. Gels and films were formed by varying the concentration of HAuCl4. Lower concentration of HAuCl4 gave films while higher concentration of HAuCl4 gave gels. The Imaging was carried out for the samples using TEM and SEM. SANS shows that the chitosan solution (liquid) had greater Rg value than the chitosan film. The Rg value did not change in gels from that of solution. There was no correlation length for the fitting for chitosan in solution, however there was correlation length observed in the gels. This indicates that in gels the chitosan units are more localized than in solution phase. Interestingly, chitosan-Au-Li film shows the formation of star like structures which are not observed in case of gels. Hence we conclude that the presence of Lithium can induce conformational changes in chitosan films while HAuCl4 can localize chitosan units in solution leading to formation of gels.