Phage
Conversion
In 1951 V.J. Freeman found that if certain nontoxigenic strains of Corynebacterium diphtheriae are treated with a phage suspension derived from a virulent toxigenic strain of the same species, a proportion of survivors acquired the ability of synthesizing the toxin as well as immunity to lytic infection by the phage.
Subsequent studies showed that this type of conversion from a nontoxigenic to toxigenic strain was due to the establishment of lysogeny (see next chapter for lysogeny) and the ability to produce the toxin was lost with the loss of the phage. Because of the correlation between lysogenization and toxin production, this phenomenon was called lysogenic conversion.
