Characterization of the action of lysozyme on Staphylococcus aureus and on Micrococcus lysodeikticus.

A recent report from this laboratory (Kingkade, Huff, and Behrens, 1948) (Iescribes experiments in which lysozyme was used to prepare bacterial cell lysates from Staphylococcus aureus K1 for use as a possible medium for bacteriophage multiplication. It was hoped that the cell wall would be ruptured allowing dispersal of the intracellular constituents into the medium without appreciable denaturation or destruction. Since in many of the experiments filtration had been used to remove any intact cells from the cell lysates, experiments were undertaken to determine whether the intracellular constituents had dispersed sufficiently to be filterable.' For this purpose electron micrographs were made of cells treated for various times with lysozyme. At the same time turbidimetric readings and determinations of cell count, both direct and viable, were made to be correlated with the results of electron micrography. Observations w^ere also made on the filtrates from the staphylococcal lysates. The action of lysozyme on Staphylococcus aureus K1 is accompanied by a gradual decrease in density at the periphery of the cell. No evidence was found of rupture of a cell membrane with a spilling of the cellular contents. The cellular masses remaining in the lysates did not pass through bacterial filters. In contrast, lysozyme causes rupture of the cell wall of Micrococcus lysodcikliclus and a dispersal of the cell contents.