Electron microscopy of mitochondria in Saccharomyces

Abstract

The mitochondria in Saccharomyces , grown on glucose nutrient agar medium, have been revealed by electron microscopy. Specimens were fixed in 2% potassium permanganate, post-fixed in 1 % uranyl acetate, and embedded in a methacrylate mixture. The yeast mitochondrion is bounded by a continuous membrane consisting of two dense layers divided by a less dense osmiophobic interspace. The inner membranes also consist of two dense outer layers and a less dense central one. The dense layers of the inner membranes are continuous with the osmiophilic layers of the outer membranes; the clear layers are directly connected with the osmiophobic interspace of the outer membrane. Both the inner membranes and the outer surface membrane are about 150 A thick.