Physiological studies on the effect of Ca2+ on the duration of the lag phase of Saccharomyces cerevisiae |
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Authors: | Jørgen Friis Leszek Szablewski Søren T Christensen Peter Schousboe Leif Rasmussen |
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Institution: | Department of Molecular Biology, Odense University Campusvej 55, DK-5230 Odense M, Denmark; Department of General Biology and Parasitology, Institute of Biostructure, Medical Academy, PL 02 004 Warsaw, Poland; Insitute of Medical Biology, Department of Anatomy and Cytology, Odense University, Campusvej 55, DK-5230 Odense M, Denmark |
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Abstract: | Abstract Cell multiplication and growth of Saccharomyces cereviseae were followed in 2-ml test tubes containing Wickerham's synthetic medium or very dilute synthetic media supplemented in various ways. The ability of the cell cultures to leave the lag phase and enter the exponential phase of growth was investigated. Multiplication was assessed by microscopical observation. The results showed great differences in times required for the cultures to leave the lag phases and begin multiplication. In Wickerham's medium, all cultures grew well 6 h after inoculation. In the dilute medium, several days elapsed before all the cultures grew. These cultures went into exponential growth with approximately first order kinetics. In the unsupplemented medium, the 'half-lives' in the lag phase were about 28 h. Addition of either Ca2+ or Ca2+ plus A23187 (calcimycin) reduced the half-lives to 10 and 6 h, respectively. The doubling times in the exponential phases of growth were not shortened by these additions. We suggest that Ca2+ plays a crucial role as a signal to switch on the mode of cell proliferation in S. cerevisiae . |
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Keywords: | Saccharomyces cerevisiae Ca ion Ca ionophore A23187 Lag phase Cell proliferation |
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