Structure and Immunochemistry of the Cell Wall Mannans from Saccharomyces chevalieri, Saccharomyces italicus, Saccharomyces diastaticus , and Saccharomyces carlsbergensis

The mannans of Saccharomyces chevalieri, S. italicus, S. diastaticus , and S. carlsbergensis , were acetolyzed, and the fragments were separated by gel filtration. All gave similar acetolysis fingerprints, which were distinguished from S. cerevisiae by the presence of a pentasaccharide component in addition to the mono-, di-, tri-, and tetrasaccharides. All oligosaccharide fragments were composed of mannose in α-linkage. From methylation analysis and other structural studies, the disaccharide was shown to be αMan(1 → 2)Man; the trisaccharide was shown to be a mixture of αMan(1 → 2)αMan (1 → 2)Man and αMan(1 → 3)αMan(1 → 2)Man; the tetrasaccharide was αMan(1 → 3)αMan(1 → 2)αMan(1 → 2)Man; and the pentasaccharide was αMan(1 → 3)αMan(1 → 3)αMan(1 → 2)αMan(1 → 2)Man. The ratios of the different fragments varied slightly from strain to strain. Mannanase digestion of two of the mannans yielded polysaccharide residues that were unbranched (1 → 6)-linked polymers, thus establishing the structural relationship between these mannans and that from S. cerevisiae . Antisera raised against the various yeasts cross-reacted with the mannans from each, and also with S. cerevisae mannan. The mannotetraose and mannopentaose acetolysis fragments gave complete inhibition of the precipitin reactions, which indicated that, in these systems as in the S. cerevisiae system, the terminal α(1 → 3)-linked mannose unit was the principal immunochemical determinant on the cell surface.