Solubility arabinogalactan

Willfor, S., Sjoholm, R., Laine, C., and Holmbom, B. (2002) Stmctural features of water-soluble arabinogalactans from Norway spmce and Scots pine heartwood. /. Wood Sci. Technol, 36, 101-110. 

Structural Studies on the Water-Soluble Arabinogalactans of Mountain and European Larch, J. K. N. Jones and P. E. Reid,/. Polym. Set., Part C, (1963) 63-71. 

Mesophyll, endosperm, and, possibly, primary, or other thin, cell walls may all have similar hemicelluloses in any one species and variety of grass. If this is so, it is of interest to consider whether thin-walled, non-endospermic cells similar to those of the endosperm possess water-soluble arabinogalactans and arabinose-rich xylans similar to those present in, or associated with, the endosperm (see Section IV). 

Larm, O., O. Theander, and P. Aman Structural Studies on a Water-soluble Arabinogalactan Isolated from Rapeseed (Brassica napus). Acta Chem. Scand. B 30, 627 (1976). 

Fincher, G. B. Stone, B. A. (1974). A water-soluble arabinogalactan-peptide from wheat endosperm. Australian Journal of Biological Science, 27,117-132. 

Golenser JS, et al. Efficacious treatment of experimental leishmaniasis with amphotericin B-arabinogalactan water-soluble derivatives. Antimicrob Agents Chemother 1999 43 2209. 

Additional polysaccharides may occur as extraneous components of wood, which are not part of the cell wall for example, the heartwood of species of larch can contain up to 25 percent (dry weight) of arabinogalactan, a water-soluble polysaccharide that occurs only in trace quantities in other wood species.5... 

Hemicelluloses in reaction woods are quite different from those in the normal woods, namely, galactan and P-(l-3)-gIucan in compression wood and galac-tan in tension wood. It is also well known that a remarkable amount of a water-soluble polysaccharide, arabinogalactan, is contained in the heartwood of larch. Since this polysaccharide occurs mainly in the lumen of tracheids and is not a cell wall component, it may not be included in hemicelluloses. Although structures and distributions of hemicelluloses have been comprehensively studied in the last 20 years, their physiologic meanings in a cell wall are not known yet. This must be the most important point for the future study of hemicelluloses. 

Hemicellulose Samples. Two water-soluble hemicellulosic samples were used (1) acetyl-4-O-methylglucuronoxylan (molecular weight = 30,000) from white birchwood, isolated by the extraction of chlorine holocellulose with dimethyl sulfoxide and (2) arabinogalactan, Stractan from St. Regis Paper Company (arabinose galactose = 1 6 molecular weight = 60,000), prepared by the water extraction of heartwood of western larch. Both samples were kindly provided by T. E. Timell (SUNY). 

Crystal appearance and growth are slower in red wines than in white wines and also differ within red wines. Arabinogalactan-proteins and mannoproteins were the major polysaccharides in the precipitates while rhamnogalaturonan II could not be detected. The average degree of polymerisation of proanthocyanidins in the deposit was higher that that of wine proanthocyanidins, indicating that polymers were selectively associated with the tartrate crystals. A preferential association of apolar fiavonols was similarly observed, presumably as their lower solubility favours adsorption on surfaces. 

Arabinogalactan is transparent both in UV and visible ranges, and electronic absorption spectroscopy can be successfully used to study arabinogalactan assisted nanoparticles. The absorption spectra of the silver and gold nanocomposites solutions have intensive absorption peaks at 420 and 524 nm, respectively (Fig. la), which proves the presence of silver and gold zero-valence metals [3]. The peaks are attributed to collective excitations of conduction electrons (plasmonic resonance). This fact is of interest for synthesis of water soluble highly efficient non-linear optical materials [1]. 

The new water soluble highly stable metal-polysaccharide nanocomposites of noble metals have been fabricated within the framework of the new approach to the synthesis of hybrid nanosized materials on the basis of arabinogalactan. Distinctive optical properties of the nanoparticles are demonstrated as the plasmonic resonance. Nanobiocomposites with target optical characteristics have a great potential to design promising multifunctional materials with controlled optical properties as well as new optical systems and optical markers in medicine. 

Wood Solubility. The solubility of wood in various solvents is a measure of the extraneous components content. No single solvent is able to remove all of the extraneous materials. Ether is relatively nonpolar and extracts fats, resins, oils, sterols, and terpenes. Ethanol/ benzene is more polar and extracts most of the ether-solubles plus most of the organic materials insoluble in water. Hot water extracts some inorganic salts and low molecular weight polysaccharides including gums and starches. Water also removes certain hemicelluloses such as the arabinogalactan gum present in larch wood see Table I). 

Some hemicelluloses have practical applications such as larch arabinogalactan, which is a water-soluble gum found in the heartwood of trees from Larix genus, and which is used in processed food as an emulsifier, or in pudding mixes, etc. A Py-GC/MS study of arabinogalactan from larch wood indicated the presence of the galactose unit and of arabinose unit in the ratio 6 1, as it is known in this material. The arabinose units were identified mainly by the formation of 1,4-anhydro-L-arabinopyranose, which elutes faster than the corresponding hexoses. The structure shown below was therefore confirmed by Py-GC/MS [64]. 

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