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Bjarne Holmbom - One of the best experts on this subject based on the ideXlab platform.
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Selective Hydrolysis of Arabinogalactan into Arabinose and Galactose Over Heterogeneous Catalysts
Catalysis Letters, 2011Co-Authors: Bright T. Kusema, Stefan Willför, Gerd Hilmann, Päivi Mäki-arvela, Bjarne Holmbom, Tapio Salmi, Dmitry Yu. MurzinAbstract:The application of solid acid catalysts for the production of monomers from hemicelluloses can be one of the key steps in developing the concept of an integrated forest biorefinery. Arabinogalactans (AG) are hemicelluloses which can be extracted on an industrial scale from larch wood species and has a great potential as a sustainable feedstock for bio-based products. Hydrolysis of AG to monomers over acidic heterogeneous catalysts (Smopex-101 and Amberlyst 15) was successfully demonstrated for the first time to selectively produce arabinose as the primary product, followed by the release of galactose without further degradation of the monomers. Graphical Abstract Selective hydrolysis of Arabinogalactan into arabinose and galactose over heterogeneous catalysts
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isolation and characterisation of water soluble polysaccharides from norway spruce and scots pine
Wood Science and Technology, 2004Co-Authors: Stefan Willför, Bjarne HolmbomAbstract:Water soluble polysaccharides from Norway spruce, Scots pine, and Siberian larch were compared. For all species the total amount of polysaccharides isolated from the heartwood was higher than that from the sapwood. The heartwood polysaccharides had a high content of galactose and arabinose units, and some glucuronic acid units, suggesting the presence of acidic Arabinogalactans. The total amounts of recovered water-soluble Arabinogalactans were 1.9 mg/g for spruce heartwood, 5.3 mg/g for pine heartwood, and as much as 106 mg/g for larch heartwood. The other water-soluble polysaccharides were mainly glucomannans. The average ratio of Gal:Ara:GlcA in the water-soluble Arabinogalactans of spruce heartwood was about 4.3:1:1, pine heartwood about 4.5:1:0.2, and larch heartwood about 6.7:1:0.1. The corresponding molar ratios then being about 3.6:1:0.8 for spruce, 3.8:1:0.2 for pine, and 5.6:1:0.08 for larch. Thus, the content of glucuronic acid units was especially high in the spruce heartwood Arabinogalactans. The content of arabinose was slightly higher in spruce and pine than in larch heartwood Arabinogalactans.
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Structural features of water-soluble Arabinogalactans from Norway spruce and Scots pine heartwood
Wood Science and Technology, 2002Co-Authors: Stefan Willför, Rainer Sjöholm, Christiane Laine, Bjarne HolmbomAbstract:Isolated water-soluble acidic Arabinogalactans from Norway spruce and Scots pine heartwood were analysed and compared to Siberian larch heartwood Arabinogalactans. The carbohydrate monomer composition was determined by acid methanolysis and gas chromatography, while structural studies were performed by 13C NMR spectroscopy and methylation analysis. The main structural features were found to be the same in the three types of Arabinogalactans. However, the structure of the Arabinogalactans from spruce and pine were found slightly different from the structure of larch Arabinogalactans. The amount of single unit side-chains, consisting of arabinose and glucuronic acid units, was higher in the spruce and pine Arabinogalactans than in the larch Arabinogalactans. The amount of glucuronic acid was higher in the spruce Arabinogalactans than in the pine Arabinogalactans. The pine Arabinogalactans had a higher amount of side chains with more than two sugar units than the spruce Arabinogalactans.
Bimalendu Ray - One of the best experts on this subject based on the ideXlab platform.
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Interaction with bovine serum albumin of an anti-oxidative pectic Arabinogalactan from Andrographis paniculata
Carbohydrate Polymers, 2014Co-Authors: Udipta R. Chatterjee, Sayani Ray, Valerie Micard, Debjani Ghosh, Kanika Ghosh, Shruti S. Bandyopadhyay, Bimalendu RayAbstract:A pectic Arabinogalactan was obtained from the leaves of Andrographis paniculata by aqueous extraction followed by a-amylase treatment, deproteination, and anion exchange chromatography. Methylation analysis, Smith degradation, and NMR spectroscopy indicated that it was a highly branched Arabinogalactan containing a (1 -> 3)-linked beta-D-Galp main chain, substituted at 0-6 by (1 -> 6)-linked beta-D-Galp side chains. The latter residues were substituted at 0-3 by (1 -> 5)- and (1 -> 3)-linked alpha-L-Araf chains, and non reducing end-units of alpha-L-Araf and beta-D-Galp. This homogeneous Arabinogalactan (36 kDa), which contained phenolic acids, showed dose-dependent anti-oxidative properties. The phenolic acid moieties might be the functional sites. This Arabinogalactan can form a complex with bovine serum albumin having binding constant K=6.48 x 10(6)/M. Thus, this study is an important step forward to investigate the involvement of Arabinogalactan in processes including interaction with biologically important transport proteins. (C) 2013 Elsevier Ltd. All rights reserved.
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Interaction with bovine serum albumin of an anti-oxidative pectic Arabinogalactan from Andrographis paniculata.
Carbohydrate polymers, 2013Co-Authors: Udipta R. Chatterjee, Sayani Ray, Valerie Micard, Debjani Ghosh, Kanika Ghosh, Shruti S. Bandyopadhyay, Bimalendu RayAbstract:Abstract A pectic Arabinogalactan was obtained from the leaves of Andrographis paniculata by aqueous extraction followed by α-amylase treatment, deproteination, and anion exchange chromatography. Methylation analysis, Smith degradation, and NMR spectroscopy indicated that it was a highly branched Arabinogalactan containing a (1 → 3)-linked β- d -Galp main chain, substituted at O-6 by (1 → 6)-linked β- d -Galp side chains. The latter residues were substituted at O-3 by (1 → 5)- and (1 → 3)-linked α- l -Araf chains, and non reducing end-units of α- l -Araf and β- d -Galp. This homogeneous Arabinogalactan (36 kDa), which contained phenolic acids, showed dose-dependent anti-oxidative properties. The phenolic acid moieties might be the functional sites. This Arabinogalactan can form a complex with bovine serum albumin having binding constant K = 6.48 × 106/M. Thus, this study is an important step forward to investigate the involvement of Arabinogalactan in processes including interaction with biologically important transport proteins.
Stefan Willför - One of the best experts on this subject based on the ideXlab platform.
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Selective Hydrolysis of Arabinogalactan into Arabinose and Galactose Over Heterogeneous Catalysts
Catalysis Letters, 2011Co-Authors: Bright T. Kusema, Stefan Willför, Gerd Hilmann, Päivi Mäki-arvela, Bjarne Holmbom, Tapio Salmi, Dmitry Yu. MurzinAbstract:The application of solid acid catalysts for the production of monomers from hemicelluloses can be one of the key steps in developing the concept of an integrated forest biorefinery. Arabinogalactans (AG) are hemicelluloses which can be extracted on an industrial scale from larch wood species and has a great potential as a sustainable feedstock for bio-based products. Hydrolysis of AG to monomers over acidic heterogeneous catalysts (Smopex-101 and Amberlyst 15) was successfully demonstrated for the first time to selectively produce arabinose as the primary product, followed by the release of galactose without further degradation of the monomers. Graphical Abstract Selective hydrolysis of Arabinogalactan into arabinose and galactose over heterogeneous catalysts
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isolation and characterisation of water soluble polysaccharides from norway spruce and scots pine
Wood Science and Technology, 2004Co-Authors: Stefan Willför, Bjarne HolmbomAbstract:Water soluble polysaccharides from Norway spruce, Scots pine, and Siberian larch were compared. For all species the total amount of polysaccharides isolated from the heartwood was higher than that from the sapwood. The heartwood polysaccharides had a high content of galactose and arabinose units, and some glucuronic acid units, suggesting the presence of acidic Arabinogalactans. The total amounts of recovered water-soluble Arabinogalactans were 1.9 mg/g for spruce heartwood, 5.3 mg/g for pine heartwood, and as much as 106 mg/g for larch heartwood. The other water-soluble polysaccharides were mainly glucomannans. The average ratio of Gal:Ara:GlcA in the water-soluble Arabinogalactans of spruce heartwood was about 4.3:1:1, pine heartwood about 4.5:1:0.2, and larch heartwood about 6.7:1:0.1. The corresponding molar ratios then being about 3.6:1:0.8 for spruce, 3.8:1:0.2 for pine, and 5.6:1:0.08 for larch. Thus, the content of glucuronic acid units was especially high in the spruce heartwood Arabinogalactans. The content of arabinose was slightly higher in spruce and pine than in larch heartwood Arabinogalactans.
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Structural features of water-soluble Arabinogalactans from Norway spruce and Scots pine heartwood
Wood Science and Technology, 2002Co-Authors: Stefan Willför, Rainer Sjöholm, Christiane Laine, Bjarne HolmbomAbstract:Isolated water-soluble acidic Arabinogalactans from Norway spruce and Scots pine heartwood were analysed and compared to Siberian larch heartwood Arabinogalactans. The carbohydrate monomer composition was determined by acid methanolysis and gas chromatography, while structural studies were performed by 13C NMR spectroscopy and methylation analysis. The main structural features were found to be the same in the three types of Arabinogalactans. However, the structure of the Arabinogalactans from spruce and pine were found slightly different from the structure of larch Arabinogalactans. The amount of single unit side-chains, consisting of arabinose and glucuronic acid units, was higher in the spruce and pine Arabinogalactans than in the larch Arabinogalactans. The amount of glucuronic acid was higher in the spruce Arabinogalactans than in the pine Arabinogalactans. The pine Arabinogalactans had a higher amount of side chains with more than two sugar units than the spruce Arabinogalactans.
Birgit Classen - One of the best experts on this subject based on the ideXlab platform.
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characterization of a yariv precipitated Arabinogalactan protein from fruits of rye secale cereale l
Die Pharmazie, 2013Co-Authors: E Goellner, W Blaschek, Birgit ClassenAbstract:: An Arabinogalactan-protein (AGP) with a molecular mass of 110 kDa was isolated from whole grain of rye (Secale cereale L.) by double precipitation with (beta-D-Glc)3-Yariv-phenylglycoside (3GlcY) and its structure was analyzed. The AGP consists of a hydroxyproline-rich protein backbone of about 7 % and an Arabinogalactan moiety of about 93%. By alkaline hydrolysis, hydroxyproline was identified as the main amino acid responsible for the binding between the protein and the carbohydrate subunits via an O-glycosidic linkage. The Arabinogalactan moieties are highly branched consisting of 1,3-linked Galp residues, some of them linked in position 6 to 1,6-Galp side chains, terminating in Araf residues. With regard to its structure, the rye AGP is comparable to other cereal AGPs like those from oat or wheat grain.
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Antibodies against Yarivʼs Reagent for Immunolocalization of Arabinogalactan-Proteins in Aerial Parts of Echinacea purpurea
Planta Medica, 2013Co-Authors: E Goellner, Jean Christian Gramann, Birgit ClassenAbstract:Arabinogalactan-proteins are glycoproteins that occur in higher plants and are involved in important processes like cell differentiation and plant growth. In the medicinal plant Echinacea purpurea L., they belong to the putative immunomodulating compounds and are structurally well characterized. For microscopic localization of Arabinogalactan-proteins, synthetic (β-D-Glc)3 Yariv phenylglycoside that specifically binds to most plant Arabinogalactan-proteins was used to label Arabinogalactan-proteins in fresh cut sections of stems and petioles of Echinacea purpurea. Polyclonal antibodies against (β-D-Glc)3 Yariv phenylglycoside were used to detect the Arabinogalactan-protein-(β-D-Glc)3 Yariv phenylglycoside complex. After addition of fluorescein isothiocyanate-conjugated secondary antibodies, the sections were analyzed by confocal laser scanning microscopy. Arabinogalactan-proteins are localized mainly in the central cylinder in the collateral vascular bundles, especially in the area of the xylem. In cell walls of fully differentiated vessels and tracheids, Arabinogalactan-proteins have been detected mainly at the inner area of the wall close to the cell lumina. Intense labeling occurs around pit canals connecting adjacent vessels. Furthermore, Arabinogalactan-proteins are present in the lumina of cells of the sclerenchyma caps and in companion cells of the phloem.
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Antibodies against Yariv's reagent for immunolocalization of Arabinogalactan-proteins in aerial parts of Echinacea purpurea.
Planta medica, 2013Co-Authors: Esther Marie Göllner, Jean Christian Gramann, Birgit ClassenAbstract:Arabinogalactan-proteins are glycoproteins that occur in higher plants and are involved in important processes like cell differentiation and plant growth. In the medicinal plant Echinacea purpurea L., they belong to the putative immunomodulating compounds and are structurally well characterized. For microscopic localization of Arabinogalactan-proteins, synthetic (β-D-Glc)3 Yariv phenylglycoside that specifically binds to most plant Arabinogalactan-proteins was used to label Arabinogalactan-proteins in fresh cut sections of stems and petioles of Echinacea purpurea. Polyclonal antibodies against (β-D-Glc)3 Yariv phenylglycoside were used to detect the Arabinogalactan-protein-(β-D-Glc)3 Yariv phenylglycoside complex. After addition of fluorescein isothiocyanate-conjugated secondary antibodies, the sections were analyzed by confocal laser scanning microscopy. Arabinogalactan-proteins are localized mainly in the central cylinder in the collateral vascular bundles, especially in the area of the xylem. In cell walls of fully differentiated vessels and tracheids, Arabinogalactan-proteins have been detected mainly at the inner area of the wall close to the cell lumina. Intense labeling occurs around pit canals connecting adjacent vessels. Furthermore, Arabinogalactan-proteins are present in the lumina of cells of the sclerenchyma caps and in companion cells of the phloem.
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Structure of Arabinogalactan from Larix laricina and its reactivity with antibodies directed against type-II-Arabinogalactans
Carbohydrate Polymers, 2011Co-Authors: E Goellner, Jon Utermoehlen, Rainer Kramer, Birgit ClassenAbstract:Abstract An Arabinogalactan from wood of the larch tree ( Larix laricina ), which is a source of dietary fiber, is composed of d -galactose and l -arabinose in a 6:1 molar ratio accompanied by small amounts of d -glucuronic acid. The molecular mass has been determined to be 38 kDa. Linkage analysis in combination with partial hydrolysis and spectroscopic investigations revealed a 1,3-linked Gal p backbone, branched at C6 to 1,6-linked Gal p side residues terminated by Gal p , Ara p , Ara f or Glc p A. Monoclonal antibodies directed against a type-II-Arabinogalactan from Echinacea purpurea showed cross reactivity with the larch Arabinogalactan and have been used to develop an ELISA for quantification of this polysaccharide.
Robert J. Redgwell - One of the best experts on this subject based on the ideXlab platform.
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Galactomannans and Arabinogalactan-proteins in the coffee bean cell wall: heterogeneity and localisation.
2005Co-Authors: Robert J. Redgwell, Paul W. Sutherland, Ian C. Hallett, M. Fischer, D. Curti, E. MacraeAbstract:Methods were developed for the isolation and fractionation of the two major groups of noncellulosic polysaccharides in the coffee bean cell wall: the (galacto)mannans and the Arabinogalactans. Chemical analysis demonstrated that both groups were chemically polydispersed with regard to their degree of backbone substitution. The galactose:arabinose ratio in the Arabinogalactans varied between 1.9 and 3.3 and the Arabinogalactans were shown to exist in the form of Arabinogalactan-proteins. The (galacto)mannans, which were studied in coffee beans at several stages of development from 11-37 weeks after flowering, showed mannose:galactose ratios as high as 2. Evidence was obtained that their final degree of galactosylation was affected by the action of an α-galactosidase during the later stages of bean development. A cytochemical and immunological study showed that the different types of polysaccharide were heterogeneously distributed across the cell wall and that during roasting the Arabinogalactans were preferentially degraded from the inner zones of the bean.
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Cytochemistry and immunolocalisation of polysaccharides and proteoglycans in the endosperm of green Arabica coffee beans
Protoplasma, 2004Co-Authors: Paul W. Sutherland, Ian C. Hallett, Elspeth A. Macrae, Monica Fischer, Robert J. RedgwellAbstract:The major noncellulosic polysaccharides and proteoglycans in the coffee bean (Coffea arabica) cell wall are (galacto)mannans and Arabinogalactan proteins. Immunological and chemical probes demonstrated that the mannans and Arabinogalactan proteins were located continuously across the width of the cell wall, but that the concentration of different structural epitopes within these polysaccharide types showed considerable spatial variation. For the mannans this was implied by the striated pattern demonstrated by fluctuation of the affinity between the mannan monoclonal antibody BGM C6 and (galacto)mannan. The Arabinogalactan proteins labelled by the Yariv reagent and the Arabinogalactan protein-specific antibody LM2 appeared to be located in all regions of the wall except the middle lamella, but showed some differences in intensity of labelling. However, the LM6 antibody, specific for (1→5)-α-arabinan epitopes, was located only as a compact region adjacent to the cell lumen in the body of the endosperm; though, it did label throughout the wall of epidermal cells. This implied that either some of the more highly arabinosylated Arabinogalactan proteins contained contiguous 5-arabinosyl residues or that a rhamnogalacturonan which contained 5-arabinosyl residues as side chains existed in the cell wall. In either case the polymers were very restricted in their distribution. A second category of pectin, a homogalacturonan detected by JIM7, was located only in the middle lamella region. The architecture of the wall, as revealed by resin etching, appeared to reflect the chemical heterogeneity, with three distinct physical zones identifiable in a cross section across a single wall.
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Coffee bean Arabinogalactans: acidic polymers covalently linked to protein.
Carbohydrate research, 2002Co-Authors: Robert J. Redgwell, Monica Fischer, Delphine Curti, Pierre Nicolas, Laurent B. FayAbstract:The Arabinogalactan content of green coffee beans (Coffea arabica var. Yellow Caturra) was released by a combination of chemical extraction and enzymatic hydrolysis of the mannan-cellulose component of the wall. Several Arabinogalactan fractions were isolated, purified by gel-permeation and ion-exchange chromatography and characterised by compositional and linkage analysis. The AG fractions contained between 6 and 8% glucuronic acid, and gave a positive test for the beta-glucosyl-Yariv reagent, a stain specific for Arabinogalactan-proteins. The protein component accounted for between 0.5 and 2.0% of the AGPs and contained between 7 and 12% hydroxyproline. The AG moieties displayed considerable heterogeneity with regard to their degree of arabinosylation and the extent and composition of their side-chains. They possessed a MW average of 650 kDa which ranged between 150 and 2000 kDa. An investigation of the structural features of the major AG fraction, released following enzymatic hydrolysis of the mannan-cellulose polymers, allowed a partial structure of coffee Arabinogalactan to be proposed.