Growth of the Escherichia coli cell surface

Phage T6 was used as a label to follow the growth of the outer membrane in a strain of Escherichia coli temperature sensitive for the production of the T6 receptor. Extension of the surface takes place at the cell poles. Small cells extend at only one pole, whereas larger cells grow from both poles. The change from unipolar to bipolar growth appears to depend on the attainment of a particular cell size and not on completion of chromosome replication.