Division synchronization in a respiratory deficient yeast.

Synchronization of cell division in a variety of microorganisms has been achieved by temperature shifts or by starvation. Two reports exist which mention svnchronization of the budding process in yeast by starvation (Beam et al., 1954; Ogur et al., 1953). In both cases, the demonstration of synchronization was incidental to the primary purpose of the experiments performed, and was therefore not quite so complete as one might like. In the present study, starvation was for glucose. Starvation for glucose alone on a complete medium was achieved by the use of a respiratory deficient strain which will grow on yeast extract and peptone only with the addition of a fermentable substrate. It was felt that, just as periodic temperature shifts have been useful in some synchronization procedures (Lark and Maaloe, 1954; Zeuthen and Scherbaum, 1954), that periodic starvation might likewise enhance the degree of synchronization. It will be seen that this expectation was not confirmed.