Oxidative stress in gills of limpets from the Beagle Channel: comparison with limpets from the Antarctic

MALANGA G; ESTEVEZ MS; CALVO J; ABELE D; PUNTARULO S

SCIENTIA MARINA

Año: 2005 vol. 69 p. 297 - 304

0214-8358

SUMMARY               The aim of this work was to study the oxidative profile of gills of two limpet species (Nacella (Patinigera) magellanica and Nacella (Patinigera) deaurata) (Gmelin, 1971) exposed to different environmental conditions. Due to tidal characteristics of the Beagle Channel, N. magellanica are daily exposed to air twice for 3 to 5 hours each time, but N. deaurata are daily exposed to air for 3 hours, only during spring tides. The different regime of exposition includes extreme temperatures under 0ºC during winter time and more than 20ºC in summer for N. magellanica, meanwhile N. deaurata are usually covered by more than 0.3 m water at 4ºC in winter and 11ºC in summer. No significant differences were determined between both molluscs regarding the oxygen uptake, the content of a-tocopherol and b-carotene and the activities of the antioxidant enzymes catalase and superoxide dismutase. Lipid peroxidation in the gills was estimated as the content of lipid radicals, assessed by electron paramagnetic resonance (EPR). Lipid radical content and total iron content were 80.6 and 62%, respectively lower in N. magellanica as compared to N. deaurata. A typical EPR spectrum of ascorbyl radical in gills from both limpets was observed. Both, ascorbyl radical content, and the ascorbyl radical content/ascorbate content ratio were significantly lower in N. magellanica as compared to N. deaurata.             The supralittoral Nacella concinna, from the Antarctic area, clearly up-staging there intertidal and subtidal relatives with respect to activities of both catalase and superoxide dismutase. Thus, it seems that Antarctic high shore conditions, involving regular exposure to air and presumably also thermal stress on sunny days during the Antarctic summer season, cause a necessity for N. concinna to ward off higher oxygen radical species production by increasing its antioxidant defense. Taken as a whole the data presented here indicated that coping with environmental demanding conditions requires a complex adjustment of the physiological metabolic pathways to ensure survival by minimizing intracellular damage.   Key words: Antarctic region, antioxidant enzymes, ascorbyl radical, ascorbate, subantarctic region