Autolysis ofBacillus colistinus

A rapid decrease was observed in suspension turbidity when exponentially growing cells of Bacillus colistinus were suspended in buffer solutions and incubated at 37°C. This phenomenon was termed autolysis. During autolysis hexosamine, a component of the cell wall, was released. Trypsin accelerated the decrease in cell suspension turbidity during autolysis but did not effect the degradation of peptidoglycan. Microscopic observations showed that cells autolysed in the presence of trypsin became empty forms within 30 min, but cells autolysed in the absence of trypsin maintained their basic structure. When autolysis was examined in relation to cell growth, cells in the middle log phase showed the maximum rate of autolysis, and trypsin accelerated the decrease in cell suspension turbidity during autolysis at every growth phase. However, the release of hexosamine from cells under autolysis did not vary among cells of exponential phase and was not accelerated by trypsin. The involvement of autolytic enzyme(s) in organism autolysis and the accelerating effect of trypsin on decreasing cell suspension turbidity were discussed.