Response of the unicellular giant algaAcetabularia Acetabulumto cadmium toxicity and accumulation∗

Abstract

Accumulation of cadmium by the unicellular marine alga Acetabularia acetabulum (=A. mediterranea) was studied by using the radioactive isotope 109 Cd. Column chromatography (Sephacryl S-200) of labelled extracts showed that after a short incubation (1-2 h) 109 Cd was eluted at the position characteristic for ionic cadmium and for low molecular weight compounds. However, after a longer incubation (one week or more), 109 Cd was present also in high molecular weight molecules.Cadmium is very toxic to Acetabularia: cell growth and cap formation were reduced at concentration as low as 1 μg L -1 . For concentrations higher than 0.1 mg L -1 , various morphological anomalies appeared, such as formation of short and thick stalks and condensation of cytoplasm in apical or basal parts, eventually followed by cytolysis.

Bioconcentration of hg inacetabularia calyculus:Evidence of a polypeptide in whole cells and anucleated cells

“…In Acetabularia acetabulum, in presence of 109 Cd, after 3 days of incubation it has been reported that this metal is present in molecules of high molecular weight. They proposed two mechanisms of accumulation: that the presence of Cd induces the synthesis of macromolecules by the cells or alternatively, Cd progressively binds onto substances of high molecular weight already found in cells 23 .…”