Ca²⁺homeostasis and redox balance in Antarctic sea organisms: Effects of temperature and of environmental contaminants

Abstract

Cell redox balance and Ca 2+ homeostasis were studied in different Antarctic sea organisms selected on the basis of their suitability for use as experimental model systems. In particular, we focused our research on the following: (1) oxidative stress and antioxidant responses in the intertidal limpet Nacella continua; (2) biochemical characterisation and metal sensitivity of the SR Ca In vivo effects of temperature and H 2 O 2 were evaluated in the limpet Nacella concinna. Production of reactive oxygen species was assessed with the dihydrorhodamine 123 fluorescent probe, lysosome alterations with histochemical techniques, and antioxidant responses through Superoxide dismutase and catalase assays. Data suggest that Nacella spring migrations to intertidal levels, where rises in temperature occur, induce oxidative stress and antioxidant response. (2) (2.5 μΜ), and of temperature on Ca 2+ homeostasis and cell viability were assessed in the ciliate Euplotes focardii. Ca 2+ homeostasis and cell viability were altered by Hg 2+ at a temperature of 0° C and above, and by Cu 2+ and Cd 2+ at 10° C and above. Temperature alone was effective at 20° and 30° C, suggesting that rises in temperature cause an increased cell sensitivity to environmental contaminants.