Abstract
Osmotic lysis of Mycoplasma organisms was found to depend on the temperature of incubation. The organisms were practically resistant to osmotic shock at 0[degree], but lysed rapidly at 37[degree]. Their sensitivity to lysis also depended on the pH value of the suspending medium, being lowest at pH values near neutrality. Divalent and polyvalent cations, in concentrations as low as 10-5[image], protected mycoplasmas from osmotic lysis. The parasitic Mycoplasma strains showed various degrees of osmotic fragility, M. gallisepticum being the least fragile. All the parasitic strains tested were, however, more resistant to osmotic lysis than the saprophytic M. laidlawii. The possibility that osmotic lysis of mycoplasmas involves autolytic processes was tested and is discussed.