The role of vacuolar digestive system in preventing cadmium poisoning in Acanthamoeba castellanii

Constituents showing cadmium affinity were found in digestive residues of the vacuolar digestive system in Acanthamoeba. Cadmium was detected by means of X-ray analysis in complexes appearing both in residues included within the digestive vacuoles and in those egested outside the cell. The digestive vacuolar system in Acanthamoeba castellanii is characterized by a particularly high turnover rate (4). Confronted with this fact, results of the present study suggest that the system is able to egest rapidly the ligand-bound cadmium. In this way protects the amoeba against serious toxic effects of the Cd-polluted environment.