Membrane Stability in Micrococcus Lysodeikticus and its Protoplasts

Abstract

The response of Micrococcus lysodeikticus and its protoplasts to storage in 1M sucrose has been studied by spectrophotometry and electron·microscopy. During several days, changes in membrane permeability properties result in the leakage of intracellular components absorbing at 260 mIL without loss of the stabil· izing effect of sucrose against osmotic explosion. Under some conditions of tempera.ture and pH, autolytic conversion of bacteria to osmotically sensitive "protoplasts" can be almost complete. Fresh protoplasts in 0·05M NaCl plus 1M sucrose are stable within the range of pH 5·5-8·0. Exposure of protoplasts to pH conditions outside these limits ca.uses lysis with disruption of the protoplast membrane.