Release of Mitochondria from Yeast Cells by the Action of Metal-Chelating Agents

Abstract

The reduction of 2,3,5-triphenyltetrazolium chloride (TTC) by resting cells of a yeast, Candida albicans, appears to be localized in particulate structures within the cells. The reduced tetrazolium (triphenylformazan, TPF) can readily be seen in structures similar to those identified as mitochondria by Mudd, et al.1, 2 in bakers' yeast and in bacteria. In the course of our studies3 on the reduction of TTC by resting cells of Candida albicans, it was observed that certain activators of the reduction, particularly potassium cyanide and the disodium salt of ethylenediaminetetraacetic acid (Na2EDTA), caused a dispersion of the waterinsoluble formazan into the medium surrounding the cells. Light microscopic studies revealed that the coloration was due only in small part to the crystallization or colloidization of TPF, and resulted mainly from the release of TPF-stained particles from the yeast cells. The particles that were released were identical with particles observed inside the cell. Indeed, particles could often be observed on the exterior of the cell wall (Fig. 1). In some instances, partly lysed cells appeared to have released large clusters of particulate material. It was possible in the following manner to demonstrate the identity of the TPF-stained bodies inside and outside of the cells. Washed resting cells which had been in contact with 0.005 per cent TTC for 5-10 min. were mounted on slides and observed under the light microscope. Illumination from the microscope light hastened the reduction of TTC inside the cells.4 When numerous TPF