Organelle Nature of a Cell Granule from a Thermophilic Bacterium.

Abstract

Photomicrographs obtained with tri-phenyltetrazolium chloride (TPTZ) and various substrates support earlier conclusions that a fraction isolated from Bacillus stearothermophilus (No. 2184) consists of cell granules. Formazan, deposited from TPTZ at local sites of oxidation, appears under the phase microscope as brilliant retractile particles. With pyruvate the intact cells deposit formazan in well-defined areas but without pyruvate there is no deposit. Isolated granules show the same behavior, but the supernatant obtained from the isolation of granules shows no activity toward pyruvate. Pyruvic oxidase thus is concentrated in the granules. Similar results can be obtained with many substrates of the isocitric cycle. Data Obtained on O2 consumption and by other means demonstrate the presence in the granule of pyruvic oxidase, succinoxidase, cyto-chrome b, alpha ketoglutaric oxidase, aconitase, isocitric de-hydrogenase, and malic dehydrogenase.