Division of Physarum mitochondria during starvation.

Microplasmodia of Physarum polycephalum used in this study form spherules after 18 h of starvation. Stereological morphometry revealed that between the 2nd and the 5th hour of starvation the number of mitochondria in 1 mm3 of cytoplasm rises from about 12 to 24 millions and the mean volume of mitochondria drops from circa 4.6 to 3.0 microns3. This denotes the synchronous division of mitochondria. The daughter mitochondria show an increase in density of the matrix and a decrease in condensation of the net of tubular cristae. The mitochondrial division, decrease in activity of the respiratory chain and maximum of its cyanide resistance occur at the same time.