PLASMOLYSIS AND BACTERIAL MOTILITY - A METHOD FOR STUDY OF MEMBRANE FUNCTION

Actively motile bacteria became non-motile when plasmolyzed and they regained their motile function when deplasmolyzed. Many of the species observed spontaneously reverted to motile forms if allowed to remain sufficiently long in the plasmolyzing medium. The time required for resumption of motility could be decreased markedly by addition of tryptone, or dl-alanyl-dl-serine, or l-alanine to the medium. Motility resumption occurred when the bacteria stained in a manner similar to that of non-plasmolyzed forms, that is, evenly rather than bipolarly, thus suggesting that the displacement of the membrane influenced motile function. The resumption of motility by plasmolyzed bacteria may serve as a simple screening test for compounds having permeability change effects on the bacterial cytoplasmic membrane as their mode of action. © 1969 Springer-Verlag.