Studies on the synthesis of staphylococcal alpha toxin

Several strains of S. aureus were induced with mitomycin C, a radiomimetic drug, and the results do not offer direct support for a general explanation for alpha toxin synthesis based upon various aspects of lysogeny. Data are also presented showing that toxin is generated intracellularly and continually released into the medium. Small alkaline changes in pH by the metabolizing culture, not affecting growth, are sufficient to stop or greatly inhibit toxin synthesis. In an actively growing culture, this phenomenon appears as a sharp rise in intracellular toxin synthesis, followed by a peak and then decline, even though the culture continues to grow and increase in optical density. Because the toxin molecule is stable at normal cultural pH values, an alkaline pH may interfere with toxin synthesis at the intracellular level.