Antioxidant defenses during the desiccation and reoxygenation cycles in the gastropod Nacella (P.) deaurata.

MALANGA G; CALVO, J; PUNTARULO S

Uruguay

Congreso; V Meeting of SFRBM - South American group and V International Conference on Peroxynitrite and Reactive Nitrogen Species; 2007

Nacella (P.) deaurata is a limpet that inhabits the intermareal and the submareal area of the Beagle Channel. In the natural environment the limpets, experiment physiological alterations between water submersion and exposure to air. This study investigated the effects of desiccation and re-oxygenation on the generation of reactive oxygen species and the activity of antioxidant enzymes in digestive glands of N. (P.) deaurata. Sampling was carried out in September 2004 in Punta Occidental (54°50´S, 68°20´W) at the Beagle Channel. The limpets were exposed to air during 5 h, then they were submerged in seawater for periods of 15 to 180 min under the same salinity and temperature conditions that in their natural environment. Immediately after each treatment the digestive glands were separated and conserved at -30ºC. The control limpets were placed in oxygen-saturated seawater over the same time period. Oxygen radical generation in limpets, evaluated as DCF-DA oxidation, showed an increase over the control values of 138%, and 48% after 15 and 30 min of re-oxygenation, respectively. DCF-DA oxidation returned approximately to control levels after 180 min of re-oxygenation. The activities of the antioxidant enzymes (superoxide dismutase, catalase and glutathione peroxidase) were spectrophotometrically determined. After 5 h of drying, the activity of superoxide dismutase in digestive glands decreased by 28% as compared to control values. After 30 min of rehydration superoxide dismutase activity increased by 39%, and returned to control values after 3 h of rehydration. Both catalase and glutathione peroxidase activities showed a similar profile. The results presented here indicate that the enzymatic antioxidant defenses of these marine organisms are a complex adaptive system to preserve cellular functioning that respond to the oxygenation cycles and dependent on the tides. This study was supported by grants from the University of Buenos Aires, ANPCYT and CONICET