DNA Content of Individual Mitochondrial Nucleoids Varies Depending on the Culture Conditions of the Yeast Saccharomyces cerevisiae

Abstract

The DNA content of individual mitochondrial nucleoids (mt-nucleoids) in the stationary-phase cells of the yeast Saccharomyces cerevisiae was quantitatively measured by a combination of DAPI-staining and use of a video-intensified microscope photon counting system (VIMPCS). The mt-nucleoids in the cells which were grown aerobically in AN medium contained, on average, 1.5 mitochondrial DNA (mtDNA) molecules per mt-nucleoid, and the mt-nucleoids that were isolated from these cells contained 1.1 mtDNA molecules per mt-nucleoid. In contrast, the giant mt-nucleoids that appeared in the cells grown anaerobically in the same medium contained, on average, 20.3 mtDNA molecules per mt-nucleoid, and the giant mt-nucleoids that were isolated from these cells contained, on average, 13.1 mtDNA molecules per mt-nucleoid. These results, together with the previous data, demonstrated that the DNA content of individual mt-nucleoids and the number of mt-nucleoids in a cell were distinctly changed by the culture conditions of the yeast cells, whereas the total mtDNA content per cell did not vary significantly when the culture conditions were changed.