On the Existence, Morphology, Nature, and Functions of the Cytoplasmic Membrane in the Bacterial Cell

Abstract

The study of spontaneously auto-lyzed cells in cultures of Bacillus cereus and B. megatherium made possible the isolation and demonstration of the cyto-plasmic membrane. The fact that this membrane is much more resistant to autolysis than the cytoplasm proper indicates considerable chemical or physicochemical differences between the 2 structures. The cytoplasmic membrane stains with dyes of the Sudan series and gives the Sharp test for proteins and a positive Feulgen reaction. It consists principally of lipoids and proteins in a highly stable chem. combination. The internal surface of the cytoplasmic membrane is jagged and wavy; besides surrounding the cytoplasm, it forms plane films which separate the cells into compartments and which are potential places of cell division; it forms and eliminates into the cytoplasm granules similar to itself in chemical composition; its demonstrated roles are in cell division and in permeability. The thickness of the cytoplasmic membrane varies even in a single cell; in young cells of B. cereus it is usually in the range 0.21 to 0.35 [mu]. The significance of the membrane''s positive Feulgen reaction is discussed.