RESPIRATORY ACTIVITY OF ISOLATED MITOCHONDRIA FROM ORGANS AND TISSUES OF THE ANTARCTIC FISH Trematomus bernacchii, Trematomus newnesi, Lepidonotothen nudifrons, and Pagothenia hansoni

Many of the key evolutionary adaptations for life in the Antarctic Ocean involve refinements of physiological and biochemical processes. Especially prominent are mechanisms that prevent freezing and allow cells, tissues and organs to carry on their metabolic activity at subzero water temperatures. In the present research work a study has been carried out on the respiration activity, assayed at 0oC, 5oC and 10oC of pectoral fin epaxial muscle and encephalon isolated mitochondria from the Antarctic fish Trematomus bernacchii, Trematomus newnesi, Lepidonotothen nudifrons, and Pagothenia hansoni using sodium succinate as substrate. For the interval between 0oC and 5oC respiration rate of encephalon mitochondria from Pagothenia hansoni increased 1.85 times, and for the interval between between 0oC and 10oC, 1.94 times. Or the fin pectoral epaxial muscle sarcsomes, there was na increasing of 1.3 times of the respiration rate between 0oC and 10oC. Respiration rates of isolated mitochondria from encephalon and fin pectoral epaxial muscle were also assayed with Trematomus bernacchii, at 0oC, Lepidonotothen nudifrons, at 0oC to 10oC and with Trematomus newnesi, at 0oC, 5oC and 10oC. The mitochondria respiratory activity was expressed in m(Mol O2 . L-1. s-1/mg of protein and respiratory control was measured between state 3 and 2 of respiration.