UNIQUE MORPHOGENESIS IN SACCHAROMYCES-CEREVISIAE STRAIN GS1731

During the lag and early exponential phase of growth, 50-60% of budded cells of Saccharomyces cerevisiae strain GS1731 were multiply budded. During subsequent culture growth, the frequency of multiply budded ce lls decreased until by stationary phase multiply budded cells were rar e. Data from renewed growth of a culture after hydroxyurea treatment i ndicated that GS1731 mother cells could assemble up to three pre-bud s ites and begin bud growth and development in each. Light and scanning electron microscopy showed two or three very small buds emerging simul taneously on a mother cell and either reaching full size at the same t ime or enlarging sequentially. Immunofluorescence studies revealed tha t these multiply budded cells had multiple bundles of cytoplasmic micr otubules. DAPI staining of nuclei revealed that some of the unbudded m other cells were multinucleate and completed cytokinesis giving rise t o normal daughter cells. (C) 1998 Federation of European Microbiologic al Societies. Published by Elsevier Science B.V. All rights reserved.