The Induction of λ-Prophage by Ionizing Radiation

The dose-response relationship for the induction of λ-prophage is a composite of the induction process and the capacity for phage development. Consequently, the character of the relation is hard to establish. Induction of lambda can be separated from capacity by studying the loss of immunity consequent on the derepression caused by ionizing radiation. The loss of immunity proves to be insensitive with a $D_{37}$ of 100 krad and shows an oxygen enhancement ratio of two or greater. The capacity for prophage development has a 37% survival dose of 45 krad and exhibits an oxygen enhancement ratio of greater than 2. These findings suggest that there is a low yield of induction by ionizing radiation because the sensitivity of the capacity is greater than the probability of induction.