Killing of Bacillus subtilis by Cell Suicide through Autolysis Induction

抄録

A novel method of killing bacterial cells by cell autolysis induction, ‘the suicide induction method, ’ was proposed. Cold shock treatment and the addition of a surfactant or a high concentration of monovalent cations used for autolysis induction were found to cause the substantial cell death of Bacillus subtilis. Enumeration with the conventional colony counting of the wild-type B. subtilis and its autolysis-defective mutant suggests that the autolysis induction is responsible for the induced cell death, namely bacterial suicide. Although no direct relationship between the cell lysis detected by the optical density decrease and the reduction in colony counts was observed, the evaluation of cell death by the respiratory activity measurement supported the above suggestion. In a continuous tube-flow system consisting of a cooling-warming cycle, bacterial suicide of B. subtilis in substantial numbers was observed. We suggest that ‘the suicide induction method’ may be applicable for practical control of some bacteria.