Galactomannans, 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... 

ACS Symposium Series 450, p. 68 (1991) Kiwitt-Haschemie, K., Renger, A., Stdnhart, H. A comparison between reductive-cleavage and standard methylation analysis for determining structural features of galactomannans. Ctirbohydrate Polymers 30, 31 (1996)... 

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. 

Reductive cleavage of the permethylated polysaccharide is recommended as a gentle alternative to hydrolysis. In this process, partially methylated anhydroalditolacetates are formed as shown in Fig. 4.42, using a galactomannan as an example. Conclusions about the structure of the polysaccharide can be drawn from the result of the qualitative and quantitative analysis, which is carried out by gas chromatography/mass... 

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