Search results for "carbohydrate"

Carbohydrates as Chemical Constituents of Biowaste Composts and their Humic and Fulvic Acids

1995

The decomposition of organic matter of source-separated biowaste during composting was followed during 18 months. Compost samples were fractionated into three parts: (i) hot water soluble extract (HWE) (ii) bitumen fraction and (iii) humic substances (humic acids (HA) and fulvic acids (FA)). Original compost samples and the HA and FA fractions were hydrolyzed with sulfuric acid for hexoses and pentoses. Quantitative spectrophotometric and qualitative GC/MS analyses of monosaccharides as trimethylsilyl ethers of the corresponding alditols were carried out.During composting, the amount of HA in the organic matter of the compost increased, the amounts of HWE and bitumen decreased and the amoun…

Carbohydrates in plant immunity and plant protection: roles and potential application as foliar sprays.

2014

International audience; Increasing interest is devoted to carbohydrates for their roles in plant immunity. Some of them are elicitors of plant defenses whereas other ones act as signaling molecules in a manner similar to phytohormones. This review first describes the main classes of carbohydrates associated to plant immunity, their role and mode of action. More precisely, the state of the art about perception of "PAMP, MAMP, and DAMP (Pathogen-, Microbe-, Damage-Associated Molecular Patterns) type" oligosaccharides is presented and examples of induced defense events are provided. A particular attention is paid to the structure/activity relationships of these compounds. The role of sugars as…

A dammarane-type saponin from the roots of Ampelozizyphus amazonicus.

1993

A new C31 dammarane-type triterpenoid saponin has been isolated from the roots of Ampelozizyphus amazonicus. Its structure was elucidated to be ampelozigenin-15 alpha-O-acetyl- 3-O-alpha-L-rhamnopyranosyl-(1--2)-beta-D-glucopyranoside by 1D and 2D NMR spectroscopic methods, and by chemical transformations. Ampelozigenin is a novel triterpene, (20R,22R)-16 beta,22:16 alpha, 30-diepoxydammar-24(24')- methylene-3 beta, 15 alpha, 20-triol.

N-Glycosylamines of 4,6-O-ethylidene-alpha-D-glucopyranose: synthesis, characterisation and structure of CO2H, Cl and F ortho-substituted phenyl deri…

2000

A saccharide based ligand suitable for metal binding (HLCOOH) has been synthesized using 4,6-O-ethylidene-alpha-D-glucopyranose (4,6-O-EGP) and anthranilic acid. A few analogous glycosylamines with chloro and fluoro ortho substitutions have also been synthesized and characterised. Complexes of HLCOOH with Na+, K+, Mg2+, Ca2+, Ba2+, Cd2+ and Hg2+ have been isolated and characterised fully. The crystal structures of 4,6-O-EGP, the chloro analogue of HLCOOH and the K+ complex of L-COOH are established. The anomeric nature, orientation of the binding core and the co-ordination aspects of K+ have been derived from these structures.

1994

The synthesis of linear carbohydrate modified polysiloxanes has been successfully performed by hydrosilation of functionalized and protected carbohydrate derivates. The functionalization (allyl glycosilation) may be applied to a wide variety of reducing carbohydrates. In this study, mono-, di- and oligosaccharides were converted by a simple two-step reaction (β-acetylation and allyl glycosilation) into active compounds, allowing the polymer analogous addition to random poly[dimethyl-co-hydromethyl]siloxanes (hydrosilation). By variation of the Si–H amount in the starting polymers, polysiloxanes with 1.5% to 56% (by weight) carbohydrate content were prepared. At small degrees of substitution…

Synthesis of Glycopeptides Containing Carbohydrate and Peptide Recognition Motifs

2000

Carbamate Linker Strategy in Solid-Phase Synthesis of Amino-Functionalized Glycoconjugates for Attachment to Solid Surfaces and Investigation of Prot…

2009

Amino-functionalized serine-based galactose and glucose neoglycolipids were prepared by solid-phase synthesis using a carbamate strategy for anchoring amino functionalities to a (2-fluoro-4-hydroxy ...

Chemoenzymatic-Chemical Synthesis of a (2-3)-Sialyl T Threonine Building Block and Its Application to the Synthesis of the N-Terminal Sequence of Leu…

2001

Protection of all functional groups of the carbohydrate portion of the chemoenzymatically synthesized sialyl T threonine ester 1 (R=R1 =H, R2 =tBu, Fmoc=9-fluorenylmethoxycarbonyl) and subsequent acidolysis of the tert-butyl ester afforded the building block 2 (R=Ac, R1 =Me, R2 =H). The latter is a useful tool in the solid-phase synthesis of the N-terminal sequence 3 of the leukemia-associated leukosialin.

Über die Verbreitung von Flavonoiden bei pleurokarpen Laubmoosen II. Apigenin and Apigenin-7-rhamnoglucosid bei Pleurozium schreberi (Willd.) Mitt.

1980

Summary 12 species of pleurocarpous mosses have been investigated as to their content of flavonoids. Flavonoid tests on 11 species have given negative results. Only one species, Pleurozium schreberi , contains three flavonoids. They were purified by means of paper chromatography. Two of them are by chromatography, acid hydrolysis and absorption spectrum identical with apigenin and apigenin-7-rhamnoglucoside. The third flavonoid is as yet unidentified. Qualitative hydrolysis yields apigenin. The chemotaxonomic importance of the results is briefly discussed.

Metal ion-promoted activation of amino acid esters of carbohydrates in the synthesis of peptides

1992

Abstract Carbohydrate esters 1 and 2 of N-protected amino acids are activated by coordination of metal ions and subjected to aminolysis by amino acid esters 3 to form peptides 4 .