TOXINOGENY INCORYNEBACTERIUM DIPHTHERIAE

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Abstract
In lysogenic, toxinogenic Corynebacterium diphtheriae, the ability to produce toxin is under the genetic control of bacteriophage. It is known that exposure of diphtheria bacilli to doses of UV light capable of inducing the multiplication of their endogenous phage (prophage) enhances their toxin output by a factor of 10 or more. This has suggested that phage multiplication is a prior requisite for the biogenesis of toxin. The present communication offers the following evidence to support this point (1) toxin is produced by carrier or pseudolysogenic complexes of phage B and C. diphtheriae; the multiplication of lytic phage B on nontoxinogenic, nonlysogenic strain C4 results in an increase in toxin. (2) Doses of UV light, which induce the endogenous cycle of phage multiplication and the formation of toxin, cause the death of the diphtheria bacillus. The formation of toxin is specifically related to the latent period of virus growth: thus toxin is released earlier from strains having a short latent period than from those having a long latent period. Toxin production appears to involve 2 stages: the first is associated with the dynamics of virus growth and is susceptible to inhibition by certain antibiotic agents; the second is a postlysis event characterized by a linear increase in toxin and may be blocked by the addition of iron.