The reversion of D-arabinose positive strains of coliform bacteria

Abstract

Bacterium lactis aerogenes adapted to d-arabinose (A + ) rather rapidly suffers a very slight reversion on subculture in glucose, and further reversion only after long periods. In media containing acetate or succinate the effect is more marked. Comparative tests with artificial mixtures of A + and A - cells show that it is not due to the re-selection of a few unadapted cells in the trained strain, but is an actual loss of A + character. Escherichia coli loses its adaptation much more readily, and the reversion is accompanied by the appearance of types intermediate in character between the A + and the A - forms.