Autolytic protoplast release in Bacterium coli.

Abstract

WE recently discovered accidentally that controlled autolysis of certain Gram-positive bacteria in concentrated sucrose solutions adjusted to a critical ionic strength at pH 6 results in the release of the internal protoplasts from the mechanical protection of the cell-wall1,2. These ‘protoplasts’ are stable in suspension media of osmotic pressure above 20 atm., but lyse in more dilute media. The observations of Alfred Fischer3 and Garbowski4 on plasmoptysis of certain Gram-negative bacteria in media of low salinity suggested that autolytic release of stable protoplasts might also be possible in these organisms. We have therefore made a preliminary investigation of the conditions required to release the protoplasts of Bacterium coli (American strain B).