SEASONAL GENE EXPRESSION OF ANTIOXIDANT ENZYMES AND HSP70 IN GILTHEAD SEA BREAM (Sparus aurata)

摘要: Seasonal changes of temperature may take organisms to the upper and lower limits of their thermal range, with respective variations in their biochemical and metabolic profile. The present study aims to investigate the seasonal cellular stress response in vital organs, ie the liver and the skeletal (red and white) muscles of the gilthead sea bream (Sparus aurata) during a 1-year acclimatization period in field conditions. The studied markers included gene expression of heat shock protein and antioxidant enzymatic activity. Specifically, molecular responses were addressed through the gene expression levels of Hsp70, superoxide dismutase (SOD) and glutathione reductase (GR). The increased gene expression levels of Hsp70, SOD and GR in the examined three tissues of the gilthead sea bream indicated a cellular stress response under the prism of a seasonal pattern characterized by distinct tissue specificity. Specifically, Hsp70 induction and the activation of antioxidant enzymes occurred before the increased summer water temperatures, with no further increases in their levels despite the increase of sea water temperature. The expression of these certain proteins can be used as a tool in order to define the extreme thermal limits of the gilthead sea bream.