THE ESTABLISHMENT OF LYSOGENICITY IN ESCHERICHIA COLI

Abstract

When a population of sensitive bacteria is exposed to infection by a temperate phage, a large number of cells are not lysed and give rise to colonies containing lysogenic cells. Some of the factors influencing the probability that an infected cell of Escherichia coli, strain K12S, will give a lysogenic response are reported here. In addition, the present study deals with the change of free phage particles into the intracellular prophage form which is transmitted to all cells in a lysogenic culture. Information was obtained on specific questions regarding the establishment of lysogenicity, as, for example: When is the decision as to the type of response, i.e., lytic or lysogenic, made by the infected cell? How much time is required for transformation (reduction) of the infecting phage into prophage and what changes take place in the host cell? Is the prophage a cytoplasmic constituent of the lysogenic cell or linked to the genetic mechanism?