Effect of carbon and nitrogen on the cannibalistic behavior of Bacillus subtilis

Abstract

Bacillus subtilis is known to exhibit cannibalism under nutrient limitation to delay sporulation. Cells of B. subtilis in phosphate buffer solution (PBS) demonstrate an oscillatory behavior in cell number due to cannibalism. Since PBS did not contain any nutrients, the effect of carbon and nitrogen sources on the cannibalistic behavior is unclear. In this study, the effect of external carbon and nitrogen on the cannibalistic behavior of B. subtilis is presented. The studies demonstrated that when glucose as a carbon source was introduced into PBS in the absence of any other nutrients, the cannibalistic tendency was delayed. This delay increased with the increase in the amount of glucose present in the PBS. Thus, the cannibalism was observed to be very sensitive to the amount of carbon present in the medium. However, when the medium contained only ammonium sulfate as a nitrogen source and was devoid of any carbon, the effect on cannibalism was minimal. The study, therefore, demonstrated that cannibalism was more sensitive to carbon than nitrogen indicating that the phenomenon of cannibalism may be more dependent on the status of energy in the medium than on nitrogen assimilation.