| Algae are vital primary producers that are sensitive to copper, an essential micronutrient and an environmental contaminant. The algal cell wall is an important protective feature against copper, yet little work has been done on mechanisms of wall protection. Since Chlamydomonas reinhardtii has been described as a copper-resistant alga via wall exclusion, a wildtype strain and a wall-less mutant were compared for differences in copper sensitivity. The wall-less strain was more sensitive, but took up less copper than would be expected if the wall were the only protective mechanism. Live and dead cell experiments with both strains suggested the possibility of a metabolically dependent copper exclusion system. The copper binding capacity of isolated wall material was similar to the wall capacity of live cells. Wall material bound more copper at pH 5 than 7, contradicting literature reports. Copper was found to outcompete other cations for binding to wall material. |
