The role of temperate bacteriophage SPβ in prophage-mediated interference in Bacillus subtilis

Publisher Website
Google Scholar
Abstract
Virulent bacteriophage .vphi. 1 grows on a variety of B. subtilis strains. Mutants of this virus were found which abortively infect the transformable bacillus, B. subtilis 168, while retaining the ability to productively infect related bacteria. The inability of 1 such variant, .vphi. 1 m, to develop normally in strain 168 is mediated by cryptic prophage SP.beta.. The latter is a temperate bacteriophage which is carried by B. subtilis 168 and most strains derived from this bacterium. .vphi. 1 m infection of SP.beta. lysogens begins with apparently normal adsorption, penetration and initiation of virus-directed syntheses. At about the 20th min of the latent period there is an abrupt cessation of nucleic acid synthesis and cellular respiration, accompanied by a change in cells permeability. This course of events can be altered to a permissive infection by mutation in the mpi gene of SP.beta., by mutation in the spo OA gene of the host or by growing SP.beta. lysogens at high temperature. A 2nd class of .vphi. 1 mutants which abortively infect B. subtilis 168 derivatives even in the absence of the SP.beta. prophage was found.