[Comparative characteristics of membrane preparations of Escherichia coli obtained by mechanical disruption]

Membrane preparations were obtained from Escherichia coli cells by the liquid and solid extrusion, ultrasonic treatment and ballistic disintegration. The preparations were subjected to biochemical analysis and studied by electron microscopy. The methods employed preserved, though to a different degree, the enzymic activity and integrity of the ribosome-membrane complex of the membrane preparations. The highest values were observed with the preparations obtained by ballistic and modified French-press disintegration. The membrane fractions obtained consisted of the cell wall and cytoplasmic membrane fragments heterogeneous in size and shape, and depending on the technique of disintegration were characterized by the presence or absence of a contact between them.