The Occurrence of Rare Motile Bacteria in some Non-motile Salmonella Strains

Abstract

The presence of rare motile bacteria in a Salmonella typhimurium O strain, SL 191/ G was investigated by a study of the spontaneous production of satellite micro-colonies in semi-solid medium, and through the isolation by micromanipulation of rare motile bacteria. These bacteria produce mainly non-motile progeny. It is considered that the motility is due to the presence of non-multiplying particles, small numbers of which are produced by some transient ability of the cell. A method was devised for measuring the frequency of such events per bacterium per generation.