Different growth response of Euglena gracilis to Hg, Cd, Cr and Ni compounds.

The toxicity of inorganic mercury, nickel, chromium and cadmium on the unicellular photosynthetic flagellate Euglena gracilis, strain Z (E.g.) has been tested. Under the conditions used each metal impaired the growth rate of E.g., and had a very strong effect on cell motility. The degree of cytotoxicity and motility decreased from mercury iodide to cadmium chloride to cadmium nitrate to potassium dichromate to nickel sulfate. No mutagenic effects of the metals investigated have been observed. Adverse effects of metal compounds can be tested on the eukaryotic species of Euglena gracilis used as an intermediate model system between bacterial and animal model.