Function-Targets-Synthesis-Analysis-Carbohydrates-l
Methods to search for new biological targets that include carbohydrate mimetics and carbohydrate scaffolds along with chip technology, are also presented.NMR assignments for glucosylated and galactosylated N-acetylhexosaminitols oligosaccharide alditols related to O-linked glycans from the protozoan parasite We report full 1H and 13C NMR assignments for 13 gluco- or galacto-pyranosylated derivatives of GlcNAc-ol, GalNAc-ol or ManNAc-ol, many of which have been prepared by enzymatic methods. These spectra are reference data to aid the structural analysis by NMR spectroscopy of glycosylated alditols derived from the mucin of the protozoan parasite Trypanosoma cruzi. A series of structural reporter groups for the derivatives from this unusual series of O-glycans are Structures of the sugar chains of a major glycoprotein present in the egg jelly coat of a starfish, Asterias amurensis.Sugar chains of a major glycoprotein, obtained from the egg jelly coat of a starfish (Asterias amurensis), were released quantitatively as oligosaccharides by hydrazinolysis. After 2'-Fucose lactose -acetylation, they were converted to radioactive oligosaccharides by reduction with NaB3H4.
Analysis by paper electrophoresis revealed that all of them were neutral oligosaccharides. Upon Bio-Gel P-4 column chromatography, the radioactive oligosaccharide mixture was separated into four components. Structural study of each component by sequential glycosidase digestion in combination with 1H-NMR spectroscopy revealed that the glycoprotein contains the following oligosaccharides, in which R represents either proton, Glc alpha 1----, Glc alpha 1----3Glc alpha 1----, or Glc alpha 1----2Glc alpha 1----3Glc alpha 1----. (Formula see text)Separation of high-mannose isomers from yeast and mammalian sources using high-pH anion-exchange chromatography.Stereoselective synthesis of 2-C-branched (acetylmethyl) oligosaccharides and glycoconjugates Lewis acid-catalyzed glycosylation from 1,2-Cyclopropaneacetylated sugars as glycosyl donors reacted with a series of glycosyl acceptors (monosaccharides, amino acids, and other alcohols) in the presence of Lewis acid to produce oligosaccharides and glycoconjugates containing 2-C-acetylmethylsugars. Galactosyl donor gave good to excellent α-selectivities with TMSOTf as a catalyst, whereas galactosyl donor offered moderate to good β-selectivities when BF(3)·Et(2)O was used as a catalyst. However, glucosyl donors produced β-exclusive selectivity under both conditions.
The stereoselectivities of glycosylation depend on the reactivity of donor sugars and Lewis acid catalyst, which effectively dictated the glycosylation pathways. The evidence suggests that galactosyl donors (e.g., 7) can undergo S(N)1 pathway with a strong Lewis acid (TMSOTf) and S(N)2 pathway under BF(3)·Et(2)O, whereas the glucosyl donors (e.g., 8 and ) followed S(N)2 pathway. The stereoselectivity was also consequential to the formation of a C2'-acetal intermediate formed via the 2-C-acetylmethyl group and the anomeric carbonium intermediate in glycosylation.
A re-evaluation of the oligosaccharide sequence associated with ovalbumin.Specific prebiotic oligosaccharides modulate the early phase of a murine The immune-modulatory effect of specific prebiotic oligosaccharides was shown in previous preclinical and clinical studies. To enhance the understanding of this effect, kinetic aspects of immune modulation and the correlation between microbiological and immunological parameters were investigated in a murine vaccination model. C57BL6 mice were supplemented with short-chain galactooligosaccharides and long-chain fructooligosaccharides (ratio 91; Immunofortis()) in combination with pectin-derived acidic oligosaccharides. The timing of supplementation was varied around the primary (day) and secondary necessary to increase delayed-type hypersensitivity responses (DTH) significantly at day . Supplementation after day 8 did not affect the DTH response at day , indicating that immune modulation occurred during the early phase. Therefore, correlation analysis of microbiological and immunological parameters was performed in a shortened experiment to focus on the early phase.
At Seebio 2'-fucosyllactose -priming, the percentages of cecal lactobacilli were correlated to the DTH responses (p1). Furthermore, the results suggested that yet unidentified factors may play a role. Additional analysis of intestinal Peyer's patch major lymphocyte populations did not show effects of supplementation. In conclusion, a specific oligosaccharide mixture was shown to exert its immune-modulatory effect during the early phase of a murine immune response. The results are consistent with a role of the microbiota and possibly other factors in oligosaccharide-induced immune modulation.
