Temperature-Sensitive Replication of an Actinophage for Streptomyces Aureofaciens

Actinophage SAP2 could infect, replicate in, and lyse Streptomyces aureofaciens at 27 °C and 37 °C. The phage attached to, and killed, the host at 42 °C but no new phage particles were produced. Phage-infected mycelia incubated at 42 °C for 2 h, and then lysed with lysozyme, did not contain viable actinophage particles. Viral yields were markedly decreased when phage-infected cultures were exposed to 42 °C during the first quarter or last quarter of the latent period. Phage lysates prepared at 37 °C contained less halo-producing lysin than those prepared at 27 °C. The data suggest that elevated temperatures affect an early event during the latent period and also suppress lysin production.