Sporothrix schenckii rhamnomannans

Fig. 21.—Partial 13C-N.m.r. Spectrum of the Rhamnomannan (16) of Sporothrix schenckii, with Shift Comparisons with Signals of Methyl a-D-Mannopyranoside (Lower Inset Lines) and Methyl a-L-Rhamnopyranoside (Upper Inset Lines). (Solvent, D20 temperature, 33° chemical shifts expressed as 8C, relative to external tetramethyl-silane.)...

Yeast forms of the dimorphic yeast Sporothrix schenckii, grown at 37°, produce128 rhamnomannan 25, but, at 25°, small proportions of 4-O- and 2,4,di-0-substituted a-D-mannopyranosyl structures129 are formed, as130 in 26, 27, and 28. Structure 25 was formed by alkaline degradation of a peptidorhamnomannan present in the cells and the culture medium.131... 

The effect was paralleled in the rhamnomannan of Sporothrix schenckii whose spectrum has signals already assigned (21). 

Rosa glauca, alginates from Laminaria digitata and L. hyperborea, oligosaccharides released by enzymic hydrolysis of agarose, the rhamnomannans and acidic rhamnomannans of Sporothrix schenckii and Ceratocystis stenoceras, and cellulose 0-methyl, 0-carboxymethyl, and 0-hydroxyethyl ethers. Details of the structures of these polymers are included in Part II of this Report. 

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. 

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