Susceptibility of Mycoplasma (Pleuropneumonia-like Organisms) and Bacterial Protoplasts to Lysis by Various Agents

THE Mycoplasma organisms (pleuropneumonia-like organisms, PPLO) are limited by a thin and plastic cell envelope 1 . The absence of diaminopimelic acid and hexosamines in Mycoplasma 2,3 indicates the absence of the ‘mucopeptide complex’ from their cell envelope. The thickness of the Mycoplasma cell envelope was found to be ∼ 75 Å. 1 , which is similar to that of the cytoplasmic membrane of bacteria 4 . These findings might indicate that the Mycoplasma have no cell wall and are limited only by a membrane resembling the cytoplasmic membrane of bacterial protoplasts. In order to elucidate this point, a comparative study of some of the properties of the Mycoplasma organisms and bacterial protoplasts was carried out.