Lysis of Mycoplasma, Bacterial Protoplasts, Spheroplasts and L-forms by Various Agents

Abstract

SUMMARY: The susceptibility to lysis of several Mycoplasma organisms, bacterial protoplasts, spheroplasts, L-forms and intact bacteria was compared. The Mycoplasma and L-forms were much more resistant to lysis by osmotic shock and to alternate freezing and thawing than were the bacterial protoplasts and spheroplasts. Like bacterial protoplasts, the mycoplasmas were very sensitive to lysis by surface-active substances, primary alcohols and alkali; bacterial spheroplasts and L-forms were less sensitive to lysis by these agents. All the organisms tested, except intact bacteria, showed various degrees of sensitivity to lysis by pancreatic lipase. The mycoplasmas and the L-forms were completely resistant to the lytic action of lysozyme. The mycoplasmas differed from all other microorganisms tested in being sensitive to lysis by digitonin and saponin. This sensitivity to digitonin was considerably smaller when the organism was grown in a cholesterol-free defined medium. The structure and properties of the Mycoplasma cell envelope are discussed on the basis of the present findings.