STRUCTURAL DETERMINATION OF D-MANNANS OF PATHOGENIC YEASTS CANDIDA-STELLATOIDEA TYPE-I STRAINS - TIMM-0310 AND ATCC-11006 COMPARED TO IFO-1397

The structures of the cell-wall D-mannans of pathogenic yeasts of Candida stellatoidea Type I strains, IFO 1397, TIMM 0310, and ATCC 11006, were investigated by mild acid and, alkaline hydrolysis, by digestion with the Arthrobacter GJM-1 strain exo-alpha-D-mannosidase, and by acetolysis. The modified D-mannans and their degradation products were studied by H-1- and C-13-n.m.r. analyses. D-Manno-oligosaccharides released by acid treatment from the parent D-mannans were identified as the homologous beta-(1 --> 2)-linked D-manno-oligosaccharides from biose to hexaose, whereas those obtained by alkaline degradation were the homologous alpha-(1 --> 2)-linked D-mannobiose and D-mannotriose. The acid- and alkali-modified D-mannans lacking H-1-n.m.r. signals above 4.900 p.p.m. [corresponding to beta-(1 --> 2)-linked D-mannopyranose units] were acetolyzed with 10:10:1 (v/v) Ac2O-AcOH-H2SO4, and the resultant D-manno-oligosaccharides were also analyzed. It was found that the longest branches of these D-mannans, corresponding to hexaosyl residues, had the following structures: alpha-D-Manp-(1 --> 3)-alpha-D-Manp-(1 --> 2)-alpha-D-Manp-(1 --> 2)-alpha-D-Manp-(1 --> 2)-alpha-D-Manp-(1 --> 2)-D-Man and alpha-D-Manp-(1 --> 2)-alpha-D-Manp-(1 --> 3)-alpha-D-Manp-(1 --> 2)-alpha-D-Manp-(1 --> 2)-alpha-D-Manp-(1 --> 2)-D-Man. These results indicate that the D-mannans of C. stellatoidea Type I strains possess structures in common with the D-mannans of Candida albicans serotype B strain (see ref. 4) containing phosphate-bound beta-(1 --> 2)-linked oligo-D-mannosyl residues.