mass of C. perfringens at the time of sporulation. The purpose of toxins is thought to be one of the following: Defense against phagocytosis, e.g., by a macrophage. Inside a host, provoking a response which is beneficial for the proliferation of the bacteria, for example in cholera. or in the case of insecticidal bacteria, killing the insect to provide a rich source of nutrients in the cadaver for bacterial growth. Food: After the target cell has ruptured and released its contents, the bacteria can scavenge the remains for nutrients or, as above, bacteria can colonise insect cadavers. Environment: The mammalian immune response helps create the anaerobic environment that anaerobic bacteria require. See also Exotoxin References Further reading A deadly toxin with a romantic name: Panton-Valentine Leukocidin complex. PDBe Quips External links Protein toxins Peripheral membrane proteins