Studies on the competence-inducing factor of Bacillus subtilis

Abstract

1. Aqueous extracts of competent cells of Bacillus subtilis 168I− were shown to contain a competence-inducing factor. The aqueous extracts were fractionated on DEAE-cellulose columns. 2. Those fractions from DEAE-cellulose columns containing the competence-inducing factor were shown to exhibit a powerful lytic effect on isolated cell walls of B. subtilis 168I−. Little or no lytic activity was exhibited by the other fractions. 3. The kinetics of the lytic enzyme were investigated and found to be first-order. Treatment of cell wall lysates with 1-fluoro-2,4-dinitrobenzene suggested that the enzyme may be identical with N-acetylmuramyl-l-alanine amidase. The amino acid composition of the partially purified enzyme was determined. 4. It is suggested that competence-induction may be dependent on the limited action of the autolytic amidase.