Mannans methylation analysis

Serologically active galactomannans, purified by way of their insoluble Fehling complexes, were obtained from mycelial and yeastlike forms of Paracoccidioides brasiliensis and Blastomyces dermaditidis, and shown by methylation analysis to consist of galactofuranosyl and mannopyranosyl units attached to a mannan core.142... 

Some idea of the future trend of methylation analysis can, perhaps, be gained from the work of Perila and Bishop, who have used the method to study oligosaccharides obtained by the enzymic hydrolysis of jack-pine mannan. The oligosaccharides (0.5-2.0 mg.) were methylated by the Kuhn procedure, refluxed with methanolic hydrogen chloride, and the resulting methyl 0-methylglycosides analyzed qualitatively and quantitatively by gas-liquid chromatography. 

P-mannans (47). The most extensive structural investigations were carried out on the mannan from the best producer, R. glutinis. An alternating arrangement of 3-(1 3)- and 3-(1 4)-linked residues was deduced from methylation analysis and characterization of di-and trisaccharides liberated by partial acid hydrolysis. Crystalline 4-0-3-g-mannopyranosyl-g-mannose was isolated in 67% yield. 

Methylation analysis and enzymic degradation studies established the presence of a structure (23) containing short side-chains of (1 -> 2)-at-D-mannosyl residues attached to a main backbone of (1 6)-ot-D-mannopyranosyl residues. In addition, a serologically inactive a-D-mannan whose structure (24) resembles that of the core L-arabino-D-mannan has been isolated. 

Studies of the chemical composition and biology of the lipopolysaccharide from Anacystis nidulans have been reported. The glycan component of this lipopolysaccharide is composed mainly of residues of o-mannose and small proportions of 3- and 4-0-methyl-D-mannose, D-galactose, D-glucose, L-fucose, 2-amino-2-deoxy-D-glucose, 2-amino-2-deoxy-D-mannose, and 3-deoxy-2-octulo-sonic acid. Methylation analysis and oxidation of the D-mannan chain with periodate revealed the presence of (1 3)- and (1 4)-linkages in the ratio 3 1. 

The results of methylation analysis and enzymic and Smith degradations indicated that the mannan consists of the pentasaccharide repeating unit (9) joined by ot-(l -> 3)-linkages. ... 

Various strains of yeasts that produce characteristic phosphono-D-mannans also synthesize characteristic extracellular a-D-mannans, which appear to differ in the degree of branching and in the type of glycosidic linkages. Methylation analysis showed that the mannans contain a fl 6)-linked a-D-mannosyl backbone, to which (1 3)-linked [e.g. (19) in Pichia mucosa] or (1 3)- and/or... 

The preferential synthesis of different polysaccharides by specific morphological types of Sporothrix schenckii has been reported. Thus, yeasts synthesize rhamnomannans containing monorhamnosyl side-chains, conidia or conidia-forming mycelia synthesize rhamnomannans with dirhamnosyl side-chains, and unsporulated mycelia synthesize galactomannans or mannans that are readily excreted into the culture medium. A combination of methylation analysis. Smith degradation, and n.m.r. spectroscopy was used to deduce the structure (25) for the D-mannan core of S. schenckii galactomannan. 

This approach88 has been applied for the identification of partially methylated mannoses, in the course of the structural analysis of Candida lipolyticua mannan.88... 

The hemicellulosic fraction of the seed endosperm of groundnuts (Arachis hypogea) contains a (l- 4)- -D-gluco-D-mannan. The homogeneity of the polymer was confirmed by electrophoresis, sedimentation, and sugar analysis. Hydrolysis of the methylated polysaccharide yielded 2,3,4,6-tetra-O-methyl-D-glucose and -D-mannose, 2,3,6-tri-O-methyl-D-glucose, and 2,3,6-tri-O-methyl-D-mannose in the molar ratio 1.6 21.2 5.6, respectively. 

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