EVIDENCE SUGGESTING THAT THE GRANULES OF MYCOBACTERIA ARE MITOCHONDRIA

Abstract

The granules of mycobacteria, interpreted by Koch as spores and variously by other investigators, were shown to be centers of oxidative-reductive enzymatic activity. Triphenyltetrazolium chloride and neotrazolium were reduced to their colored formazans in these mycobacterial granules. Such reduction has been shown to be catalyzed by the flavoprotein dehydrogenase diaphorase. The Nadi reaction for cytochrome oxidase was positive also in these granules. The mycobacterial granules stained initially blue green with Janus green B; reduction of this specific mitochondrial stain in the granules changed their color to red which finally fades. The granules gave the Baker stain for phospholipin and the Harman mitochondrial stain. Morphologically the mycobacterial granules resembled the mitochondria of animal cells in size, contour and plasticity. When the granules were volatilized in the electron microscope by intense electron bombardment, wrinkled and torn surface membranes remained. Since the granules of mycobacteria were shown to resemble mitochondria in all enzymatic, tinctorial and morphological attributes in which they have been compared, the authors conclude that they are mitochondria. This we believe to be the first definitive recognition of mitochondria in bacteria. Bacteria in another aspect are demonstrated to have fundamental attributes in common with other organisms.