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Jian-xin Jiang - One of the best experts on this subject based on the ideXlab platform.
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physicochemical characterization of Galactomannans extracted from seeds of gleditsia sinensis lam and fenugreek comparison with commercial guar gum
International Journal of Biological Macromolecules, 2020Co-Authors: Yantao Liu, Fuhou Lei, Jian-xin JiangAbstract:Gleditsia sinensis, fenugreek and guar Galactomannans (referred to as GSG, FG, and GG) were extracted from their gums and investigated using various techniques. Mannose to galactose ratios were 3.55, 1.11, and 1.65, respectively. The intrinsic viscosity of GSG was very close to that of GG, while that of FG was the lowest one. This was attributed to the influence of high galactose substitution of FG on the mannan backbone, which induced a lower chain dimension due to intermolecular entanglement. High degrees of substitution and high temperatures contributed to improving the solubility of Galactomannan. Rheological behavior indicated that GG had the highest apparent viscosity, yet the power-law model could well-fitted the flow curves of GSG and FG, but not GG. Through morphological observations, the extracted Galactomannans exhibited rod-like structure in deionized water and showed fibrous filament network structure after dehydration by freeze-drying. The thermal behavior was greatly influenced by the degree of side groups and Mw of Galactomannans.
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Comparison and characterization of Galactomannan at different developmental stages of Gleditsia sinensis Lam.
Carbohydrate Polymers, 2019Co-Authors: Yantao Liu, Fuhou Lei, Jian-xin JiangAbstract:Abstract Pods from a Gleditsia sinensis Lam. tree were collected and the Galactomannan content and other properties were determined at their different developmental stages. In green and immature seed, Galactomannan was substituted to a great extent with a mannose to galactose (M/G) ratio of 2.4 from crude polysaccharides. During late Galactomannan deposition, it was substituted to a lower extent and this ratio increased rapidly, reaching a M/G ratio of 3.1. Average molecular weight (Mw) of the extracted polysaccharides first increased, reached the maximum (1.19 × 106) at 17 weeks after flowering (WAF), and then decreased. These changes might result from primary Galactomannan biosynthesis and from galactose removal by α-galactosidase in the endosperm. The solubility of crude polysaccharides decreased with increased M/G ratio and maximum solubility was more than 89% that collected at 13 WAF. Rheological properties showed that apparent viscosity was largely influenced by the molecular weight and M/G ratio of Galactomannans.
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physicochemical characteristics of gradual fractionation ingredients of industrial Galactomannan gums from gleditsia microphylla and cyamopsis tetragonoloba
Bioresources, 2016Co-Authors: Yudong Liu, Jian-xin Jiang, Jianxiong Xing, Juanhan Liu, Jinghuan Chen, Kun Wang, Runcang SunAbstract:Galactomannan in industrial Gleditsia microphylla and guar gum was successfully fractionated by gradual precipitation in an aqueous solution with increasing ethanol concentrations. The molecular properties of each fraction were characterized, and the Galactomannans were added to photopolymerized hydrogels to test their effects on mechanical properties and swelling capacity. In the series fractions of guar gum, the sample precipitated from 20% EtOH solution had the highest yield, mannose to galactose ratio, and viscosity, and it had a slightly lower molecular weight than that precipitated by 30% EtOH. Correspondingly, the best tensile property of its photopolymerized hydrogel was finally detected. In terms of G. microphylla gum, the precipitation in 30% EtOH solution achieved the highest yield, M/G ratio, and molecular weight value, and it exhibited the best rheological property of all the samples. The hydrogel with the addition of this sample also had the best mechanical properties despite its lower hydroscopicity than the blank hydrogel. The unique properties of each fraction could probably lead to their use as biodegradable alternatives in different applications.
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Characterization of fractional polysaccharides from Gleditsia sinensis and Gleditsia microphylla gums
Molecules, 2016Co-Authors: Yantao Liu, Zhenglong Xu, Jiufang Duan, Jian-xin Jiang, Wei-an Zhang, Da Feng SunAbstract:The seeds of Gleditsia sinensis and Gleditsia microphylla, widespread in China, are an important source of Galactomannans. G. sinensis gum (GSG) and G. microphylla gum (GMG) were purified and precipitated using different concentrations of ethanol and isopropanol. The GSG and GMG, precipitated in different stages, presented different characteristics, including polymer recovery, mannose/galactose ratio, chemical composition, molecular weight, and morphological appearance. The Galactomannan recovery of GSG and GMG in 33.3% ethanol was 81.7% and 82.5%, respectively, while that in 28.8% isopropanol was 81.3% and 82.9%, respectively. To achieve similar precipitation efficiency, the amount of isopropanol should be lower than that of ethanol because of the lower dielectric constant of isopropanol (20 vs. 25 for ethanol). The precipitation behavior of Galactomannans in polar organic solvents was dependent on the molecular structures and properties of the solvent. A higher mannose/galactose ratio and a higher molecular weight was obtained in a lower concentration of alcohols.
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Characterization of fractional precipitation behavior of Galactomannan gums with ethanol and isopropanol
Food Hydrocolloids, 2014Co-Authors: Hong-lei Jian, Da Feng Sun, Xue-jiao Lin, Zhang Weian, Wei-ming Zhang, Jian-xin JiangAbstract:Three Galactomannans of guar gum (GG), locust bean gum (LBG) and fenugreek gum (FG) were fractionally precipitated from pure solutions by the addition of either ethanol or isopropanol. The Galactomannan precipitates were formed when the bulk solutions containing >18.6% (v/v) ethanol or 13.5% (v/v) isopropanol. The Galactomannan recovery of GG, LBG and FG in 33.3% ethanol solvent was 93.1, 86.1 and 94.5%, respectively, while that in 28.8% isopropanol solvent was 94.1, 92.5 and 97.7%, respectively. To achieve the same precipitation efficiency, the usage amount of isopropanol was much lower than that of ethanol, owing to the low dielectric constant for isopropanol (20 vs. 25). It was demonstrated that the precipitation behavior of Galactomannans in polar organic solvents was dependent on the molecular structure, such as molecular weight and galactose substitution.
Elin S. Olafsdottir - One of the best experts on this subject based on the ideXlab platform.
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structural characterisation of a highly branched Galactomannan from the lichen peltigera canina by methylation analysis and nmr spectroscopy
Carbohydrate Polymers, 2006Co-Authors: Sesselja Omarsdottir, Hilde Barsett, Smestad B Paulsen, Jens Ø. Duus, Bent O. Petersen, Elin S. OlafsdottirAbstract:Abstract An alkali-extractable water-soluble polysaccharide, Pc-4, was isolated from the lichen Peltigera canina using ethanol fractionation and size exclusion chromatography. The average molecular weight of Pc-4 was estimated to be 53 kDa. Structural characterisation of Pc-4 was performed by methanolysis, methylation analysis and NMR-spectroscopy (1D proton, COSY, NOESY, TOCSY and HSQC). According to data obtained, Pc-4 is a highly branched Galactomannan, with (1→6)-linked α-mannopyranosyl units in the main chain, which are mainly disubstituted at O2 and O4 by single unsubstituted units of α-Manp and β-Galp, respectively. Pc-4 resembles the lichen Galactomannans described previously; however, Pc-4 has higher degree of branching.
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structural characterisation of a highly branched Galactomannan from the lichen peltigera canina by methylation analysis and nmr spectroscopy
Carbohydrate Polymers, 2006Co-Authors: Sesselja Omarsdottir, Hilde Barsett, Smestad B Paulsen, Jens Ø. Duus, Bent O. Petersen, Elin S. OlafsdottirAbstract:Abstract An alkali-extractable water-soluble polysaccharide, Pc-4, was isolated from the lichen Peltigera canina using ethanol fractionation and size exclusion chromatography. The average molecular weight of Pc-4 was estimated to be 53 kDa. Structural characterisation of Pc-4 was performed by methanolysis, methylation analysis and NMR-spectroscopy (1D proton, COSY, NOESY, TOCSY and HSQC). According to data obtained, Pc-4 is a highly branched Galactomannan, with (1→6)-linked α-mannopyranosyl units in the main chain, which are mainly disubstituted at O2 and O4 by single unsubstituted units of α-Manp and β-Galp, respectively. Pc-4 resembles the lichen Galactomannans described previously; however, Pc-4 has higher degree of branching.
Yantao Liu - One of the best experts on this subject based on the ideXlab platform.
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physicochemical characterization of Galactomannans extracted from seeds of gleditsia sinensis lam and fenugreek comparison with commercial guar gum
International Journal of Biological Macromolecules, 2020Co-Authors: Yantao Liu, Fuhou Lei, Jian-xin JiangAbstract:Gleditsia sinensis, fenugreek and guar Galactomannans (referred to as GSG, FG, and GG) were extracted from their gums and investigated using various techniques. Mannose to galactose ratios were 3.55, 1.11, and 1.65, respectively. The intrinsic viscosity of GSG was very close to that of GG, while that of FG was the lowest one. This was attributed to the influence of high galactose substitution of FG on the mannan backbone, which induced a lower chain dimension due to intermolecular entanglement. High degrees of substitution and high temperatures contributed to improving the solubility of Galactomannan. Rheological behavior indicated that GG had the highest apparent viscosity, yet the power-law model could well-fitted the flow curves of GSG and FG, but not GG. Through morphological observations, the extracted Galactomannans exhibited rod-like structure in deionized water and showed fibrous filament network structure after dehydration by freeze-drying. The thermal behavior was greatly influenced by the degree of side groups and Mw of Galactomannans.
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Comparison and characterization of Galactomannan at different developmental stages of Gleditsia sinensis Lam.
Carbohydrate Polymers, 2019Co-Authors: Yantao Liu, Fuhou Lei, Jian-xin JiangAbstract:Abstract Pods from a Gleditsia sinensis Lam. tree were collected and the Galactomannan content and other properties were determined at their different developmental stages. In green and immature seed, Galactomannan was substituted to a great extent with a mannose to galactose (M/G) ratio of 2.4 from crude polysaccharides. During late Galactomannan deposition, it was substituted to a lower extent and this ratio increased rapidly, reaching a M/G ratio of 3.1. Average molecular weight (Mw) of the extracted polysaccharides first increased, reached the maximum (1.19 × 106) at 17 weeks after flowering (WAF), and then decreased. These changes might result from primary Galactomannan biosynthesis and from galactose removal by α-galactosidase in the endosperm. The solubility of crude polysaccharides decreased with increased M/G ratio and maximum solubility was more than 89% that collected at 13 WAF. Rheological properties showed that apparent viscosity was largely influenced by the molecular weight and M/G ratio of Galactomannans.
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Characterization of fractional polysaccharides from Gleditsia sinensis and Gleditsia microphylla gums
Molecules, 2016Co-Authors: Yantao Liu, Zhenglong Xu, Jiufang Duan, Jian-xin Jiang, Wei-an Zhang, Da Feng SunAbstract:The seeds of Gleditsia sinensis and Gleditsia microphylla, widespread in China, are an important source of Galactomannans. G. sinensis gum (GSG) and G. microphylla gum (GMG) were purified and precipitated using different concentrations of ethanol and isopropanol. The GSG and GMG, precipitated in different stages, presented different characteristics, including polymer recovery, mannose/galactose ratio, chemical composition, molecular weight, and morphological appearance. The Galactomannan recovery of GSG and GMG in 33.3% ethanol was 81.7% and 82.5%, respectively, while that in 28.8% isopropanol was 81.3% and 82.9%, respectively. To achieve similar precipitation efficiency, the amount of isopropanol should be lower than that of ethanol because of the lower dielectric constant of isopropanol (20 vs. 25 for ethanol). The precipitation behavior of Galactomannans in polar organic solvents was dependent on the molecular structures and properties of the solvent. A higher mannose/galactose ratio and a higher molecular weight was obtained in a lower concentration of alcohols.
Henrik Stalbrand - One of the best experts on this subject based on the ideXlab platform.
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a β mannan utilization locus in bacteroides ovatus involves a gh36 α galactosidase active on Galactomannans
FEBS Letters, 2016Co-Authors: Sumitha K. Reddy, Viktoria Bagenholm, Hanene Bouraoui, Nicholas A. Pudlo, Nicole M Koropatkin, Eric C Martens, Henrik StalbrandAbstract:The Bacova_02091 gene in the β-mannan utilization locus of Bacteroides ovatus encodes a family GH36 α-galactosidase (BoGal36A), transcriptionally upregulated during growth on Galactomannan. Characterization of recombinant BoGal36A reveals unique properties compared to other GH36 α-galactosidases, which preferentially hydrolyse terminal α-galactose in raffinose family oligosaccharides. BoGal36A prefers hydrolysing internal galactose substitutions from intact and depolymerized Galactomannan. BoGal36A efficiently releases (> 90%) galactose from guar and locust bean Galactomannans, resulting in precipitation of the polysaccharides. As compared to other GH36 structures, the BoGal36A 3D model displays a loop deletion, resulting in a wider active site cleft which likely can accommodate a galactose-substituted polymannose backbone.
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Expression and characterization of a bifidobacterium adolescentis beta-mannanase carrying mannan-binding and cell association motifs
Applied and Environmental Microbiology, 2013Co-Authors: Evelina Kulcinskaja, Anna Rosengren, Romany Ibrahim, Katarina Kolenova, Henrik StalbrandAbstract:The gene encoding β-mannanase (EC 3.2.1.78) BaMan26A from the bacterium Bifidobacterium adolescentis (living in the human gut) was cloned and the gene product characterized. The enzyme was found to be modular and to contain a putative signal peptide. It possesses a catalytic module of the glycoside hydrolase family 26, a predicted immunoglobulin-like module, and two putative carbohydrate-binding modules (CBMs) of family 23. The enzyme is likely cell attached either by the sortase mechanism (LPXTG motif) or via a C-terminal transmembrane helix. The gene was expressed in Escherichia coli without the native signal peptide or the cell anchor. Two variants were made: one containing all four modules, designated BaMan26A-101K, and one truncated before the CBMs, designated BaMan26A-53K. BaMan26A-101K, which contains the CBMs, showed an affinity to carob Galactomannan having a dissociation constant of 0.34 μM (8.8 mg/liter), whereas BaMan26A-53K did not bind, showing that at least one of the putative CBMs of family 23 is mannan binding. For BaMan26A-53K, k(cat) was determined to be 444 s(-1) and K(m) 21.3 g/liter using carob Galactomannan as the substrate at the optimal pH of 5.3. Both of the enzyme variants hydrolyzed konjac glucomannan, as well as carob and guar gum Galactomannans to a mixture of oligosaccharides. The dominant product from ivory nut mannan was found to be mannotriose. Mannobiose and mannotetraose were produced to a lesser extent, as shown by high-performance anion-exchange chromatography. Mannobiose was not hydrolyzed, and mannotriose was hydrolyzed at a significantly lower rate than the longer oligosaccharides.
Marcos Silveira Buckeridge - One of the best experts on this subject based on the ideXlab platform.
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effect of abscisic acid on the mobilisation of Galactomannan and embryo development of sesbania virgata cav pers leguminosae faboideae
Brazilian Journal of Botany, 2002Co-Authors: Adriana Potomati, Marcos Silveira BuckeridgeAbstract:Galactomannans (GM) are storage cell wall polysaccharides present in endospermic seeds of legumes. They are thought to be storage polymers, since it has been observed for a few species (among them Sesbania virgata) that they are completely broken down after germination and their products are transferred to the growing embryo. We examined the effect of 10-4 M abscisic acid (ABA) on the degradation of Galactomannan in isolated endosperms and intact seeds of S. virgata. We found that after seed germination the initial embryo growth was retarded. Ultrastructural analysis showed that the embryo is completely surrounded by an endosperm which displays very thick Galactomannan-containing cell walls. Although an inhibitory effect has been observed on the increase of fresh mass of the embryo, the effect of ABA on the dry mass was weaker and transitory (from 48 to 96 h). Endosperm dry mass and Galactomannan degradation were significantly inhibited and the activity of a-galactosidase was strongly affected. The addition of ABA before and/or after the start of mobilisation in intact seeds or isolated endosperms, showed that whereas addition before mobilisation did not affect dry mass decrease in intact seeds, it was strongly affected in isolated endosperms. On the other hand, whereas it affected embryo fresh mass increase in intact seeds, but not in isolated embryos, no significant effect was observed on dry mass. These results suggest that ABA affects Galactomannan degradation and by doing so, prevents water absorption by the embryo, rather than affect its dry mass. As ABA has been detected in the endosperm of seeds of S. virgata, it is proposed that it probably acts as a modulator of Galactomannan mobilisation and consequently synchronises it with early growth of the embryo.
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mobilisation of storage cell wall polysaccharides in seeds
Plant Physiology and Biochemistry, 2000Co-Authors: Marcos Silveira Buckeridge, Henrique Pessoa Dos Santos, Marco Aurelio Silva TineAbstract:Plants store carbohydrate polymers in a number of forms. Starch is the principal form, followed by fructans and cell wall storage polysaccharides (CWSP). The latter are present mainly in seeds and consist of magnifications of one of the polysaccharides present in one of the cell wall matrices. CWSPs are classified as mannans, xyloglucans and galactans, the first being subdivided into pure mannans, Galactomannans and glucomannans. The present review updates the principal discoveries concerning occurrence, structure, metabolism and eco-physiological significance of the seed storage cell wall polysaccharides with emphasis on their importance for plant metabolism and adaptation to their respective environments during evolution. The properties of CWSPs as storage polysaccharides are compared with starch and fructans and the current knowledge on the catabolism (including control) of mannan/Galactomannan, xyloglucan, and galactan is reviewed. On the basis of these data, the idea that the CWSPs are multifunctional molecules is proposed and this feature is used as evidence for the hypothesis that, during evolution, the CWSPs were involved in cycles of transference of functions which led them to become storage polysaccharides, yet preserving some of their previous primary cell wall functions.
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Mobilisation of the raffinose family oligosaccharides and Galactomannan in germinating seeds of Sesbania marginata Benth. (Leguminosae-Faboideae)
Plant Science, 1996Co-Authors: Marcos Silveira Buckeridge, Sonia M. C. DietrichAbstract:Seeds of the tropical species Sesbania marginata present a living endosperm whose cells possess thickened walls which contain Galactomannan. Oligosaccharides of the raffinose family and protein bodies are stored intracellularly. Between the seed coat and the endosperm an aleurone layer is present. The anatomy of the endosperm of Sesbania marginata is intermediate amongst other Galactomannan-containing seeds that have been anatomically examined (Trigonella foenum-graecum and Ceratonia siliqua). Before radicle protrusion, oligosaccharides from the raffinose family are broken down concomitantly in the endosperm and embryo whereas Galactomannan (apparently restricted to the endosperm) is degraded after germination. Three Galactomannan hydrolases: α-galactosidase, endo-β-mannanase and β- mannosidase were detected in isolated endosperms and their activities peaked during the exponential phase of Galactomannan degradation, suggesting their close correlation with the breakdown of this cell wall polysaccharide following germination. Our results indicate that unlike Trigonellafoenum- graecum enzymes, the hydrolases of seeds of Sesbania marginata seem not to work in a concerted fashion, since the mannose:galactose ratio of the polysaccharide increased significantly at the end of the degradation process, suggesting that α-galactosidase attacks the polymer before the other hydrolases. The products of Galactomannan degradation (galactose and mannose) do not accumulate either in the endosperm or in the embryo, where they are probably metabolised and used as a source of energy for the early growth of the plantlet.
