title: Altered immunochemical reactivity of Saccharomyces cerevisiae a-cells after alpha-factor-induced morphogenesis.
abstract: Antibodies were raised against Saccharomyces cerevisiae a-cells that had been exposed to the sex pheromone, alpha-factor. After adsorption of the antiserum with diploid cells, antibodies remained that reacted specifically with the mannan from haploid cells. The characteristic determinant was observed in mannan from pheromone-treated a-cells, in mannan from untreated alpha-cells, and at a much lower concentration, in mannan from control a-cells. The antigens from these three mannans appeared to be identical. The determinant was destroyed by mild-acid hydrolysis or periodate oxidation, but not by proteolysis or digestion with exo-alpha-mannanase. Mutants with altered mannan were unable to express the antigen. Complete acid hydrolysates mannan from alpha-factor-treated a-cells contained mannose, glucose, and N-acetylglucosamine. Partial acid hydrolysis, under conditions that destroyed the antigenic determinant, released only mannose and mannobiose. The mannose fraction was labeled to high specific activity during response of a-cells to alpha-factor if radioactive glucose was the carbon source. Neither alpha- not beta-D-mannopyranosyl phosphate was a hapten. The results are consistent with the presence of a haploid-specific antigen containing an acid-labile mannose determinant and show that the amount of this antigen in a-cell mannan is increased in response to alpha-factor.
mesh_terms: D000946:Antigens, Fungal / Q000032:analysis*; D005656:Fungal Proteins / Q000494:pharmacology*; D006241:Haptens / Q000032:analysis; D006868:Hydrolysis; D008351:Mannans / Q000032:analysis / Q000276:immunology*; D000072235:Mating Factor; D009024:Morphogenesis; D009154:Mutation; D010455:Peptides; D011134:Polysaccharides / Q000276:immunology*; D012441:Saccharomyces cerevisiae / Q000187:drug effects / Q000276:immunology*
chemical_list: D000946:Antigens, Fungal; D005656:Fungal Proteins; D006241:Haptens; D008351:Mannans; D010455:Peptides; D011134:Polysaccharides; D000072235:Mating Factor