Understanding the rich complement of sugar chains found in cellular membranes is impeded by the complexity of cell types and membrane diversity. To overcome this, we have analyzed the N-linked sugar chain composition of the glycoproteins of CNS myelin, an elaboration of the plasma membranes of oligodendrocytes (OLs) that result in a multilamellar wrapping of neuronal axons, facilitating nerve conduction with dramatic savings of space and energy. Due to an usually high lipid to protein ratio, myelin can be separated readily from other heavier membranes on sucrose gradients and further fractionated into subdomains related to myelin structure and function, including compact myelin and myelin-associated axolemmal membrane (Menon et al. 2003). We analyzed these fractions for N-linked sugar chains, using 2D HPLC following hydrazinolysis and pyridylamination. Our results indicate that compared with total brain homogenate, the amount of N-glycans is 1.3-fold higher in the myelin-associated axolemmal membranes, but it is 0.5-fold less in CM. M5 [Manalpha1-3((Manalpha1-3)(Manalpha1-6)Manalpha1-6)Manbeta1-4GlcNAcbeta1-4GlcNAc] is the most abundant sugar chain in total brain homogenate, compact myelin, and myelin-associated axolemma, constituting approximately 20% of sugar chains. Although the types of sugar chains are similar among the fractions, their expression levels vary significantly. In addition to high mannose type oligosaccharides, the core fucosylated, biantennary N-glycans with bisecting N-acetylglucosamine (GlcNAc) residue, A2G1(3)FB [Galbeta1-4GlcNAcbeta1-2Manalpha1-3(GlcNAcbeta1-2Manalpha1-6)(GlcNAcbeta1-4)Manbeta1-4GlcNAcbeta1-4(Fucalpha1-6)GlcNAc], A2G1(6)FB [GlcNAcbeta1-2Manalpha1-3(Galbeta1-4GlcNAcbeta1-2Manalpha1-6)(GlcNAcbeta1-4)Manbeta1-4GlcNAcbeta1-4 (Fucalpha1-6)GlcNAc] and BA-1 [Manalpha1-3(GlcNAcbeta1-2Manalpha1-6)(GlcNAcbeta1-4)Manbeta1-4GlcNAcbeta1-4(Fucalpha1-6)GlcNAc], and A1(6)G0F [Manalpha1-3(GlcNAcbeta1-2Manalpha1-6)Manbeta1-4GlcNAcbeta1-4(Fucalpha1-6) GlcNAc] are also present in relatively large proportions in compact myelin. We suggest that these differences may be related to myelin-axolemmal function.
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Alzheimers Dement
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Department of Neuroregeneration, Netherlands Institute for Neuroscience, Institute of the Royal Netherlands Academy of Arts and Sciences, Amsterdam, The Netherlands.
Introduction: Some individuals show intact cognition despite the presence of neuropathological hallmarks of Alzheimer's disease (AD). The plasticity of parvalbumin (PV)-containing interneurons might contribute to resilience. Perineuronal nets (PNNs), that is, extracellular matrix structures around neurons, modulate PV neuron function.
View Article and Find Full Text PDFProteoglycan Res
October 2024
Department of Biochemistry and Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA.
Hyaluronan (HA; [-3-GlcNAc-1-beta-4-GlcA-1-beta] ), an essential matrix polysaccharide of vertebrates and the molecular camouflage coating in certain pathogens, is polymerized by "HA synthase" (HAS) enzymes. Three HAS classes have been identified with biotechnological utility, but only the Class II PmHAS from Type A has been useful for preparation of very defined HA polymers in vitro. Two general chemoenzymatic strategies with different size products are possible: (1) repetitive step-wise extension reactions by sequential addition of a single monosaccharide from a donor UDP-sugar onto an acceptor (or "primer") comprised of a short glycosaminoglycan chain (e.
View Article and Find Full Text PDFSci Rep
December 2024
Department of Statistical Science, Duke University, Durham, 27708-0251, USA.
The article is motivated by an application to the EarlyBird cohort study aiming to explore how anthropometrics and clinical and metabolic processes are associated with obesity and glucose control during childhood. There is interest in inferring the relationship between dynamically changing and high-dimensional metabolites and a longitudinal response. Important aspects of the analysis include the selection of the important set of metabolites and the accommodation of missing data in both response and covariate values.
View Article and Find Full Text PDFJ Food Sci
December 2024
College of Food Science & Institute of Food Biotechnology, South China Agricultural University, Guangzhou, China.
Gut bacterial lipopolysaccharide (LPS) could be released into the circulatory system via the gut-liver axis and cause inflammatory immune response, while Cordyceps militaris polysaccharide (CMP40) has been reported to be effective in alleviating this inflammatory response. In this study, the effects of CMP40 gut fermentation on internal LPS structure formation and the subsequent immune response were explored. Results showed that CMP40 could change antigenicity of LPS of Vibrio parahaemolyticus, Salmonella enterica, and enterotoxigenic Escherichia coli, indicated by a reduced level of NO, IL-1β, IL-6, and TNF-α.
View Article and Find Full Text PDFMar Drugs
December 2024
G.B. Elyakov Pacific Institute of Bioorganic Chemistry, Far Eastern Branch of the Russian Academy of Sciences, Pr. 100-letya Vladivostoka 159, 690022 Vladivostok, Russia.
Five new non-holostane di- and trisulfated triterpene pentaosides, conicospermiumosides A-1 (), A-2 (), A-3 (), A-1 (), and A-2 () were isolated from the Far Eastern sea cucumber Levin et Stepanov (Cucumariidae, Dendrochirotida). Twelve known glycosides found earlier in other species were also obtained and identified. The structures of new compounds were established on the basis of extensive analysis of the 1D and 2D NMR spectra, as well as by the HR-ESI-MS data.
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