CYSTS OF AZOTOBACTER

Abstract

Electron micrographs of ultrathin sections of the azotobacter cysts show striking differences from vegetative cells. Cysts are disrupted by (ethylenedinitrilo) tetraacetic acid (EDTA),, whereas vegetative cells are not. Cyst development can be followed using this procedure. Like endospores, cysts have a negligible endogenous activity, but unlike endospores, show high respiratory capacity on substrates utilized by the vegetative cells of the species. The central body ejected from the cyst coat by EDTA action also shows considerable respiratory activity, although lower than that of the intact cyst. The central body is protoplast-like in that it is metabolically active only when stabilized in a medium of high osmotic pressure, but it differs, since it will remain intact without a stabilizing medium. Furthermore, it is sensitive to lysozyme action suggesting presence of cell wall materials.