Observations on Vegetative Nuclear Division in Saccharomyces Cerevisiae

In Giemsa-stained preparations of actively growing yeast, nuclear division normally occurred in the isthmus of each bud, but occasionally the nucleus divided in the parent cell and one of the products of division entered the bud, or else division occurred in the bud, following which one of the two nuclei migrated back into the parent cell. The frequency of intrabud divisions was increased by thymine, dihydrothymine, and thymidine. During normal division, the nuclear material entering the bud tended to be organized into two parallel rows, each comprising three densely staining bodies, and the latter were grouped into apparently homologous pairs.