Prophage map of converting corynebacteriophage beta

Abstract

A prophage map for corynebacteriophage beta consisting of seven markers has been constructed and compared with the vegetative map. The mapping system utilizes heteroimmune double lysogens and capitalizes on the fact that these double lysogens are very unstable and throw off monolysogenic segregants. The prophage map, produced by characterizing the recombinant phage in these monolysogenic segregants, appears to be a cyclic permutation of the vegetative map with the gene for toxin at one end of the prophage map and the gene for phage immunity at the other. This permutation is in accord with the Campbell model for insertion of lambda phage if a site between the toxin and immunity genes in the vegetative map is designated as the phage attachment site. The position of the gene for toxin in the prophage map suggests that converting phages may have originated as specialized transducing phages for this gene.

Corynebacterium ulcerans and Corynebacterium pseudotuberculosis responses to DNA probes derived from corynephage beta and Corynebacterium diphtheriae

“…Lanes A to D are C. ulcerans strains, lanes E to H are C. diphtheriae strains, and lanes I to L are C. pseudotuberculosis strains. could be in the phage genome itself or in the adjacent bacterial genome, for it is known that the tox gene is located at the extreme end of a prophage arm (17). It has been shown for C. diphtheriae (24) that there are at least two bacterial sites into which 13-or 13-related-converting phages can insert as prophage, and our data suggest that there are two sites for the fox gene in at least one strain of C. ulcerans and therefore at least two sites for the integration of converting phage in that strain.…”

Effect of metal ions on diphtheria toxin production

“…Testing for toxinogenesis. A previously described modification of the standard in vitro gel immunodiffusion tests for toxinogenesis (6) was used. Two filter paper strips (approximately 6 by 0.6 cm) saturated with antitoxin (200 to 400 antitoxin units/ ml) were placed in parallel on the surface of the plate containing supplemented KL virulence agar.…”

“…In view of increased interest in the regulation of toxin synthesis, we undertook to reexamine the inhibitory effect of metal ions on toxin production. Since it seemed desirable to study a number of metal ions over a wide range of concentrations, we used a simple test system, a modified gel immunodiffusion plate system (6) in which the effect of metal ions on growth and toxin production could be simultaneously assessed.…”

Restriction map of corynebacteriophages beta c and beta vir and physical localization of the diphtheria tox operon

“…A partial genetic map of vegetative ,B phage has been described by Holmes and Barksdale (14), Matsuda et al (17), and Singer (25). Although genetic analysis clearly demonstrated that /8 phage carried a tox determinant, it was not until Uchida et al (28) isolated nontoxigenic mutants of /8 that tox was shown to be the structural gene for diphtheria toxin. The prophage map of 8 is a circular permutation of the vegetative map (15). This observation suggested that linear /8 DNA has cohesive ends which allow the genome to circularize and to integrate into the corynebacterial chromosome according to the Campbell model (4).…”