Propionate induced lysis of protoplasts of Bacillus megaterium.

Previous studies (Storck and Wachsman, 1957; Weibull, Beckman, and Bergstrom, 1959; Wachsman, Fukuhara, and Nisman, 1960) on enzyme localization were performed with cell fractions, obtained by lysing protoplasts in media of low osmotic pressure. In an attempt to determine the effect of the tonicity of the lysing medium on the distribution of enzyme activities between the membrane containing and supernatant fractions, a study of methods for protoplast lysis in 0.25 M sucrose was undertaken. This concentration of sucrose is usually sufficient to stabilize the protoplasts of Bacillus megateriuim (Weibull, 1953). A possible method for lysing protoplasts in a normally isotonic medium was suggested by the recent studies on energy dependent permeation mechanisms in bacteria (Rickenberg et al., 1956; Cohen and Monod, 1957). The lysozyme protoplast of Escherichia coli contains a galactoside-permease (Rickenberg, 1957; Sistrom, 1958) which may catalyze the intracellular accumulation of galactosides to a level several hundred-fold greater than that of the extracellular concentration. The present work shows that propionate, or any one of a variety of other low molecular weight compounds, can induce a rapid lysis of B. megaterium protoplasts in 0.25 M sucrose. The resulting lysate contains intact cytoplasmic membranes that appear almost free of contamination with other microscopically detectable cell components. The lytic phenomenon is energy dependent and can best be explained in terms of an osmotic shock, resulting from the active transport and intracellular accumulation of the low molecular weight compound.