The effect of lysogenic induction on the deoxyribonucleases of Escherichia coli K12(λ)
1964; Elsevier BV; Volume: 22; Issue: 1 Linguagem: Inglês
10.1016/0042-6822(64)90051-0
ISSN1096-0341
Autores Tópico(s)Bacterial Genetics and Biotechnology
ResumoIn association with the induction of phage development in E. coli K12(λ), or during lethal infection of E. coli K12S with the phage λ, there is a marked rise in cellular DNase activity which is due to the appearance of a new phage-related exonuclease. When induction is carried out with mitomycin C, synthesis of the new DNase begins early in the latent period and continues until phage maturation is complete or until lysis occurs. During thymineless induction, enzyme synthesis begins early in the induction period and continues for as long as thymine deprivation is maintained. Upon addition of thymine to the culture, which permits viral DNA replication to begin, there is an abrupt cessation of DNase synthesis. These data suggest that an early step in the induction process allows the expression of the transcription functions of the λ-prophage independently of its replication, and that control of the cessation of virus-directed enzyme formation is in some way related to viral DNA synthesis. Superinfection of a lysogenically induced culture of K12(λ)thy− with the noninducible phage λ ind− results in a parallel inhibition of the induction process and of DNase formation. This may indicate that λ ind− acts by blocking the ability of prophage DNA to initiate enzyme synthesis.
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