Helleborus caucasicus is a perennial herbaceous plant whose roots contain cardiac glycosides. The new compound hellecaucaside A was isolated from its roots. 2'-O-alpha-D-Ribofuranosyluridine, a ...structural fragment of hellecaucaside A, was synthesized.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
The unexpected, non‐enzymatic S‐glycosylation of cysteine residues in various proteins by per‐O‐acetylated monosaccharides is described. This artificial S‐glycosylation greatly compromises the ...specificity and validity of metabolic glycan labeling in living cells by per‐O‐acetylated azido and alkynyl sugars, which has been overlooked in the field for decades. It is demonstrated that the use of unacetylated unnatural sugars can avoid the artifact formation and a corrected list of O‐GlcNAcylated proteins and O‐GlcNAc sites in HeLa cells has been assembled by using N‐azidoacetylgalactosamine (GalNAz).
Being specific: Per‐O‐acetylated monosaccharides induce an unexpected, non‐enzymatic cysteine S‐glycosylation of various proteins. This artificial S‐glycosylation greatly compromises the specificity and validity of metabolic glycan labeling in living cells, but can be overcome by using unacetylated unnatural sugars. A corrected list of O‐GlcNAcylated proteins and O‐GlcNAc sites in HeLa cells has been compiled by using GalNAz.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Misgurnus anguillicaudatus, also known as oriental weather loach, is widely consumed and favored in East Asia due to its superior nutritional values and excellent flavor. In this study, a crude ...Misgurnus anguillicaudatus carbohydrates (MAC) was isolated from Misgurnus anguillicaudatus. Subsequently, two parts, which were named MAO and MAP, respectively, were separated from MAC, and their primary structures and immunomodulatory activity were investigated. The results showed that MAO had a molecular weight of 2854 Da, and principally consisted of arabinose (77.11%) and rhamnose (21.97%), together with minor levels of fucose (0.92%); MAP, with a molecular weight of 3873 Da, was mainly composed of fucose (87.55%) and a small amount of rhamnose (8.86%) and galactose (3.59%). The in vitro assay showed that MAC could significantly enhance the proliferation of macrophages without cytotoxicity and increase the production of immune substances (TNF-α, IL-6). Together with Western blot results, we speculated that MAC could stimulate RAW264.7 murine macrophage cells to secrete TNF-α and IL-6 through up-regulating TLR4-MAPK-p38 signaling pathways. The results indicated that MAC could be a potential immune agent and might provide meaningful information for further chain conformation and immune mechanism research.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Polysaccharides with molecular weights ranging from 1.75 × 10sup.3 to 1.14 × 10sup.4 g/mol were obtained from the fruit bodies of Ganoderma lucidum. The multiple fingerprints and macrophage ...immunostimulatory activity of these fractions were analyzed as well as the fingerprint-activity relationship. The correlation analysis of molecular weight and immune activity demonstrated that polysaccharides with molecular weights of 4.27 × 10sup.3~5.27 × 10sup.3 and 1 × 10sup.4~1.14 × 10sup.4 g/mol were the main active fractions. Moreover, the results showed that galactose, mannose, and glucuronic acid were positively related to immunostimulatory activity. Additionally, partial least-squares regression and grey correlation degree analyses indicated that three peaks (P2, P3, P8) in the oligosaccharide fragment fingerprint significantly affected the immune activity of the polysaccharides. Hence, these ingredients associated with activity could be considered as markers to assess Ganoderma lucidum polysaccharides and their related products, and the study also provides a reference for research on the spectrum-effect relationship of polysaccharides in the future.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Per-O-acetylated unnatural monosaccharides containing a bioorthogonal group have been widely used for metabolic glycan labeling (MGL) in live cells for two decades, but it is only recently that we ...discovered the existence of an artificial “S-glycosylation” between protein cysteines and per-O-acetylated sugars. While efforts are being made to avoid this nonspecific reaction in MGL, the reaction mechanism remains unknown. Here, we present a detailed mechanistic investigation, which unveils the “S-glycosylation” being an atypical glycosylation termed S-glyco-modification. In alkaline protein microenvironments, per-O-acetylated monosaccharides undergo base-promoted β-elimination to form thiol-reactive α,β-unsaturated aldehydes, which then react with cysteine residues via Michael addition. This S-glyco-modification produces 3-thiolated sugars in hemiacetal form, rather than typical glycosides. The elimination–addition mechanism guides us to develop 1,6-di-O-propionyl-N-azidoacetylgalactosamine (1,6-Pr2GalNAz) as an improved unnatural monosaccharide for MGL.
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IJS, KILJ, NUK, PNG, UL, UM
Soybean (Glycine max L.) has been extensively cultivated in maize-soybean relay intercropping systems in southwest China. However, during the early co-growth period, soybean seedlings suffer from ...severe shading by maize resulting in lodging and significant yield reduction. The purpose of the present research was to investigate the reasons behind severe lodging and yield loss. Therefore, four different soybean genotypes (B3, B15, B23, and B24) having different agronomic characteristics were cultivated in intercropping and monocropping planting patterns. The results showed that under different planting patterns, the stem resistance varied among genotypes (P < 0.01). The lodging resistance index of B3, B15, B23, and B24 genotypes was 70.9%, 60.5%, 65.2%, and 57.4%, respectively, under intercropping, among which the B24 genotype was less affected by the shade environment as there was little decrease in the lodging resistance index of this genotype under intercropping. The lignin content of B23 and B24 was significantly higher than that of B3 and B15 under both planting patterns. Under intercropping, the hemicellulose content of B23 and B24 stems was significantly higher than that of B3 and B15. Compared to the monocropping, the content of mannose in the structural carbohydrate of soybean stems was decreased in all genotypes except B23, but the difference was not significant. The content of xylose in the structural carbohydrate of soybean stems was significantly higher than that in B3 and B15. Mannose content showed no significant difference among genotypes. The arabinose content of B24 was significantly higher than that of B3, B15, and B23. The effective pod number, seed number per plant, seed weight per plant and yield of soybean plants were significantly decreased under intercropping. Conclusively, manipulation of structural and nonstructural carbohydrate rich soybean genotypes in intercropping systems could alleviate the yield loss due to lodging.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Advances in the chemical synthesis of C-pyranosides/furanosides are summarized, covering the literature from 2000 to 2016. The majority of the methods take advantage of the construction of the ...glycosidic CC bond. These C-glycosylation methods are categorized herein in terms of the glycosyl donor precursors, which are commonly used in O-glycoside synthesis and are easily accessible to nonspecialists. They include glycosyl halides, glycals, sugar acetates, sugar lactols, sugar lactones, 1,2-anhydro sugars, thioglycosides/sulfoxides/sulfones, selenoglycosides/telluroglycosides, methyl glycosides, and glycosyl imidates/phosphates. Mechanistically, C-glycosylation reactions can involve glycosyl electrophilic/cationic species, anionic species, radical species, or transition-metal complexes, which are discussed as subcategories under each type of sugar precursor. Moreover, intramolecular rearrangements, such as the Claisen rearrangement, Ramberg–Bäcklund rearrangement, and 1,2-Wittig rearrangement, which usually involve concerted pathways, constitute another category of C-glycosylations. An alternative to the C-glycosylations is the formation of pyranoside/furanoside rings after construction of the predetermined glycosidic CC bonds, which might involve cyclization of acyclic precursors or D–A cycloadditions. Throughout, the stereoselectivity in the formation of the resultant C-glycosidic linkages is highlighted.
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