Acid-soluble deoxynucleotides and DNA synthesis in growing yeast after x-irradiation. I. Diphenylamine positive material in synchronized and asynchronously growing cells.

In synchronized growing yeast, the level of acid-soluble purine deoxynucleotides, as determined by the diphenylamine reaction, fluctuates rhythmically: A rapid increase each time before DNA starts to replicate is followed by a considerable decrease during DNA augmentation. Delay of DNA replication by irradiation of synchronized yeast with 50 kr of X-rays results in a stepwise augmentation of deoxyribose derivatives. The fluctuating behaviour is restored, when DNA starts to increase, again. During asynchronous growth acid-soluble deoxyribosidic compounds are augmented with a considerably increased rate, when DNA replication is delayed by X-rays. The resulting unusual pool seize is maintained, even if DNA replication is resumed to a normal degree, but the rate of further increase is reduced to normal values. Parts of the rapidly accumulated deoxyribosidic material differ with some properties from purine deoxynucleotides.