Electron Microscopical Studies on Growing Fungal Cells

I. Nuclear Division and Accompanying Behavior of Mitochondria in the Genus Candida

Abstract

The mode of nuclear separation and the accompanying behavior of mitochondria in budding yeast-like cells of the genus Candida were studied at the electron microscopical level.
In this fungus, the nucleus showed to separate in the fission manner analogous in nature to that reported in the genus Saccharomyces. In the process of bud formation, the dumbell-shaped nucleus migrated from the mother cell into the bud separates as if it were pulled apart. The nuclear separation occurred in a narrow neck region of the cytoplasm slightly inside a bud cell. Then one of the daughter nuclei withdrew into the mother cell. There was no evidence suggesting definitely that the nucleus might separate completely in the mother cell at the initial stage of bud formation, and that one of the two nuclei might migrate into the bud cell.
Some of the mitochondria migrated into the bud cell prior to the nuclear migration, and others were observed to be situated along the migrating nucleus or at the nuclear site where the separation had occurred. These configuration might indicate that mitochondria played an active role in the migration and separation of the nucleus during the process of bud formation.
The nucleoplasm of Candida was generally homogeneous, although less electron-dense areas sometimes were visible scattered within the nucleus. In the present study, therefore, the significance of chromosome- or chromatin-division during the process of bud formation remained to be clarified in future.