No abstract

Aim. Determine the effect of mitochondrial DNA loss on the formation of complex yeast colonies of Saccharomyces cerevisiae. Methods. Development of giant colonies of the parent strain SK1 (rho+) and the "petit" strain SK1p, which lost mtDNA (rho0 mutation), was observed for 40 days,. To find out zones of cell death in colonies, both strains were cultured on solid YPD media containing dyes that accumulate in dead cells. The survival of the cells within colony was estimated by the ability to create microcolonies.  Results. The loss of mitochondrial DNA in SK1p cells led to a decrease in colony area and to simplification of colony morphology on the YPD medium. When SK1p colonies were cultivated on media with addition of dyes, bright spot was formed in the center due to the dyes accumulation  in dead cells. At the same time, parent strain developed a uniform insignificant coloration.  Conclusions. rho0 mutation in SK1p yeast strain Saccharomyces cerevisiae led to a significant simplification of complex colony structure that formed on the nutrient medium YPD. The mitochondrial DNA loss in strain SK1p results in an accelerated cell death in the center of colony on YPD.Keywords: Saccharomyces cerevisiae, rho0, colonies, cell survival.