Formation of the Vegetative Pool by Induced Defective and Healthy Lysogenic Strains of Escherichia coli

Abstract

SUMMARY: Comparison of two defective λ prophages carried by strains of Escherichia coli, with respect to their physiological properties following induction, has revealed that one defective mutant (λ i 2) can multiply normally as vegetative phage but cannot mature into normal infectious phage, whereas the other defective phage (λ i1) can undergo only limited multiplication since it is unstable in the vegetative state. Consideration of the properties of λ i 1 has led to an hypothesis that radiation induction causes the prophage to produce a vegetative replica which becomes autonomous rather than conversion of the prophage into vegetative phage.