Distinctly different characteristics of flocculation in yeast

Abstract

Flocculation of cells of S. cerevisiae NCYC 1109 and S. cerevisiae NCYC 234 was studied. Both cells flocculated 48 h after inoculation although the cells grown for only 20 h were non-flocculent. EDTA inhibited the flocculation of cells of S. cerevisiae NCYC 1109 and Ca2+ enhanced it. Protein-denaturants, D-mannose and D-glucose depressed the flocculation of cells of NCYC 1109. Treatment with proteolytic enzymes, photo-irradiation in the presence of methylene blue or periodate oxidation caused a loss of the floc-forming ability of the ceils of NCYC 1109. On the contrary, the flocculation of ceils of NCYC 234 was not affected by EDTA and Ca2+. Protein-denaturants and monosaccharides did not inhibit the flocculent ability of cells of NCYC 234. Neither proteolytic enzyme treatments, photo-irradiation in the presence of methylene blue nor periodate oxidation, deprived the cells of NCYC 234 of the floc-forming ability. Cycloheximide repressed induction of the floc-forming ability of growing cells of NCYC 1109 significantly but not of growing cells of NCYC 234. These results suggest that the mechanisms of flocculation of NCYC 1109 and NCYC 234 are quite different.