Incorporation of phosphorus into phased cells ofCandida utilis using32P and33P

Changes in phosphorus metabolism were studied by examining the incorporation of³²P and³³P into cells ofCandida utilis growing in phased culture during a 6 h cell cycle and a post-cycle period of 6 h. Three different chemically defined media were used; these were phosphorus, nitrogen and carbon limited. The patterns of incorporation of phosphorus into RNA, DNA, lipid and cold water extractable phosphate fractions showed a non-uniform behaviour during both cell cycle and post-cycle periods. The patterns were different in all three types of media. The results showed that a cell can grow and develop at a fixed growth rate in different ways: so that the pattern of behaviour during a cell cycle is not stereotyped for a given doubling time, but largely depends upon the nutrient environment in which the cell exists.