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B. Giardina et al.
efficiency of one of the main metabolic pathways could be maintained at a
reasonable level.
Conclusions
As far as the oxidative metabolism is concerned, specific adaptive features
are apparent in Antarctic fishes. These features emerge from a number of
observations relative to:
1. the aerobic energy metabolism that appears to be predominantly reliant
upon the oxidation of fatty substrates i.e. upon a preferential utilization
of the lipid metabolic pathway;
2. the significant increase of antioxidant defenses as evident by the
amount of vitamin E, coenzyme Q, selenium, zinc and copper which
characterize Antarctic fish tissues. This significant increase is in full
agreement with point 1 and with the additional roles which have been
hypothesized for the peculiar lipid accumulation observed in these
organisms (see also point 4);
3. the specific form of coenzyme Q involved in the reactions of the
respiratory chain. Although this finding needs to be further
investigated it could be related to the different crystallization
temperatures displayed by CoQg and COQIO and/or by its higher
antioxidant activity;
4. the peculiar lipid accumulation very likely linked to acceleration of
oxygen diffusion between capillary and mitochondria and to the
necessity of an oxygen store to minimize changes in oxygen supply to
mitochondria at the muscular level.
However, in parallel with these fascinating biochemical adaptations, we
have to consider the very narrow range of temperature in which the various
complexes of the respiratory chain maintain their biological activity. The
stringent stenothermality which characterizes the biological activity of
mitochondria of Antarctic fish and in particular the icefish appears to be
the cost that has to be paid for the impressive fitness of these organisms to
their extreme environment.
References
1. Littlepage JL (1965) Oceanographic investigations in McMurdo Sound,
Antarctic. In: Llano GA (ed) Biology of Antarctic seas II. Antarctic Res Ser,
Am Geophys Union, Washington DC 5:1-37
2. Everson I (1970) The population dynamics and energy budget of Notothenia
neglecta Nybelin at Signy Island, South Orkney Islands. Bull Br Antarct
Surv 23:25-50
B. Giardina et al.
efficiency of one of the main metabolic pathways could be maintained at a
reasonable level.
Conclusions
As far as the oxidative metabolism is concerned, specific adaptive features
are apparent in Antarctic fishes. These features emerge from a number of
observations relative to:
1. the aerobic energy metabolism that appears to be predominantly reliant
upon the oxidation of fatty substrates i.e. upon a preferential utilization
of the lipid metabolic pathway;
2. the significant increase of antioxidant defenses as evident by the
amount of vitamin E, coenzyme Q, selenium, zinc and copper which
characterize Antarctic fish tissues. This significant increase is in full
agreement with point 1 and with the additional roles which have been
hypothesized for the peculiar lipid accumulation observed in these
organisms (see also point 4);
3. the specific form of coenzyme Q involved in the reactions of the
respiratory chain. Although this finding needs to be further
investigated it could be related to the different crystallization
temperatures displayed by CoQg and COQIO and/or by its higher
antioxidant activity;
4. the peculiar lipid accumulation very likely linked to acceleration of
oxygen diffusion between capillary and mitochondria and to the
necessity of an oxygen store to minimize changes in oxygen supply to
mitochondria at the muscular level.
However, in parallel with these fascinating biochemical adaptations, we
have to consider the very narrow range of temperature in which the various
complexes of the respiratory chain maintain their biological activity. The
stringent stenothermality which characterizes the biological activity of
mitochondria of Antarctic fish and in particular the icefish appears to be
the cost that has to be paid for the impressive fitness of these organisms to
their extreme environment.
References
1. Littlepage JL (1965) Oceanographic investigations in McMurdo Sound,
Antarctic. In: Llano GA (ed) Biology of Antarctic seas II. Antarctic Res Ser,
Am Geophys Union, Washington DC 5:1-37
2. Everson I (1970) The population dynamics and energy budget of Notothenia
neglecta Nybelin at Signy Island, South Orkney Islands. Bull Br Antarct
Surv 23:25-50