Cell-wall Lysins of Staphylococcus Aureus Strains Induced by Specific Typing Phages.

Ralston, Doris J. (University of California, Berkeley), and Mary McIvor. Cell-wall lysins of Staphylococcus aureus strains induced by specific typing phages. J. Bacteriol. 88:667-675. 1964.-At least 12 different phages induced the formation of soluble lysins (separable from the phages by ultracentrifugation). The lysins caused rapid clearing of heat-killed cells of all strains of Staphylococcus aureus tested, irrespective of the capacity of the phage to form plaques on living cells of the strain. The uninfected cells of the 12 strains contained a second lysin, an autolysin, released upon cellular autolysis. The autolysin preparations differed from the phage-induced lysins, in that they exhibited relatively high activity for lysing Micrococcus lysodeikticus and low activity for strain S. aureus K(1N), and were each specifically inhibited by antiserum prepared against purified autolysin from strain K(1). A third kind of lysin, virolysin, induced by polyvalent phage K, was differentiated from the lysins of the specific phages on the basis of its antigenic specificity and lack of action on M. lysodeikticus. All three kinds of lysins digested the mucopeptide portion of staphylococcal cell walls. No evidence was found that any of these lysins possessed specific host ranges which could be correlated with the lytic host range of the inducing phage.