A study by freeze-etching of the fine structure of Micrococcus radiodurans.

Abstract

1. This study of the fine structure of Micrococcus radiodurans by freeze-etching confirmed and extended earlier results obtained with thin sections and negatively-stained preparations. The cell wall consists of three layers, and its outer surface shows a characteristic hexagonal array of hollow rings with a centre-to-centre spacing of about 18 nm. In dividing cells, septum formation begins at several points on the periphery of the cell and often proceeds asymmetrically until the septum is complete. 2. These results, together with other studies, show that the structure of the cell wall of M. radiodurans is not that typical of Gram-positive cocci, and that it has some features in common with the walls of Gram-negative bacteria, and some unique features. M. radiodurans should therefore be reclassified into a new taxon.