Abstract
The cell division of the fission yeast, Schizosaccharomyces pombe, was synchronized by the preincubation of cells at a high cell-density (1×109 cells per ml) for about one generation time followed by the dilution of the cell suspension by 100 times with a fresh medium. During the preincubation at the high cell density, glucose in culture medium was rapidly exhausted and the total nitrogen decreased corresponding to an increase in cellular nitrogen, while only a slight increase in cell number occurred initially. In the course of the crowded culture, the content of nucleic acid, mainly RNA, increased definitely at the expense of intracellular acid-soluble phosphorus compounds, while the amount of polyphosphate and DNA remained unchanged. In connection with these observations, the phasing mechanism of cellular age by the present method is discussed.
During the course of synchronized culture, synthesis of RNA seemed to proceed very actively in the earlier phase of a cell cycle and that of DNA in the later stage just before the cell division, whereas the amount of protein increased almost linearly throughout the whole cycle.
