Mechanism of aluminium tolerance in Cyanidium caldarium

Cyanidium caldarium, an acidophilic, thermophilic red alga, specifically to lerates Al. The tolerance increases at lower culture temperatures. The intr acellular Al concentration is kept at low levels, especially when the cells are cultured at lower temperatures. Lower Al incorporation accounts for th e Al tolerance in this alga. Fe incorporation antagonizes the Al incorporat ion, implying that Fe transporters incorporate Al ions. Treatment with an u ncoupler, carbonylcyanide m-chlorophenylhydrazone, increases the intracellu lar concentration of Al. These results support the hypothesis that Al ions taken up by the algal cells are exported by an energy-dependent mechanism.