Structural determination of d-mannans of pathogenic yeasts Candida stellatoidea type I strains: TIMM 0310 and ATCC 11006 compared to IFO 1397

Abstract

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-α- d-mannosidase, and by acetolysis. The modified d-mannans and their degradation products were studied by 1H- and 13C-n.m.r. analysis. d-Manno-oligosaccharides released by acid treatment from the parent d-mannans were identified as the homologous β-(1 → 2)-linked d-manno-oligosaccharides from biose to hexaose, whereas those obtained by alkaline degradation were the homologous α-(1 → 2)-linked d-mannobiose and d-mannotriose. The acid- and alkali-modified d-mannans lacking 1H-n.m.r. signals above 4.900 p.p.m. [corresponding to β-(1 → 2)-linked d-mannopyranose units] were acetolyzed with 10:10:1 (v/v) Ac 2O-AcOH-H 2SO 4, and the resultant d-manno-oligosaccharides were also analyzed. It was found that the longest branches of the d-mannans, corresponding to hexaosyl residues, had the following structures: α- d-Man p-(1 → 3)-α- d-Man p-(1 → 2)-α- d-Man p-(1 → 2)-α- d-Man p-(1 → 2)- d-Man and α- d-Man p-(1 → 2)-α- d-Man p-(1 → 3)-α- d-Man p-(1 → 2)-α- d-Man p-(1 → 2)-α- d-Man p-(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 β-(1 → 2)-linked oligo- d-mannosyl residues.