Summary
Cannibalism, the feeding on sibling cells, is an intriguing survival strategy of the Gram-positive bacterium Bacillus subtilis in response to nutrient limitation. It allows to delay entry into the costly process of sporulation until definitely necessary. Cannibal cells, in which the master regulator of sporulation Spo0A is activated by phosphorylation, produce two peptide toxins - sporulation delay protein (SDP) and sporulation killing factor (SKF) - that act cooperatively to kill non-sporulating sibling cells, in which Spo0A is inactive and hence are not protected by immunity. The process can be considered as a “programmed cell death”-strategy of a heterogenic cell population during biofilm maturation.
We are investigating cell killing by the cooperative action of SDP and SKF and explore developmental traits affecting the susceptibility to cannibalistic killing. We aim to identify autolysins and other factors involved in cell lysis or the activation of autolysins during cannibalism and to elucidate the flow of cell fragments from prey to cannibal cells.
