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(80-49) Variability of antioxidant defenses in Mediterranean and Antarctic sea-urchins: sentinel organisms for monitoring environmental disturbance in coastal waters? Razzetti, Erika1, Regoli, Francesco*,1, 1 University of Ancona, Ancona, Italy ABSTRACT- Despite the fact that all aerobic organisms are prone to toxicity of oxyradicals produced as intermediates of normal metabolism, these effects are particularly important when intracellular generation of ROS is exacerbated. Basic comparative studies on the susceptibility to oxidative stress in marine invertebrates are of interest since the basal levels of oxygen detoxification systems may reflect the natural prooxidant pressure to which organisms are exposed. In this respect, the antioxidant efficiency has been characterized in two sea urchin related species respectively from the Mediterranean (Paracentrotus lividus) and the Antarctic marine environment (Sterechinus neumayeri). Sea urchins are widely distributed along coastal environments where they can be directly exposed to anthropogenic contaminants but also to wide fluctuations of environmental factors. Water warming is suggested to have an increasing ecological role in the Mediterranean where several episodes of invertebrates mass-mortality have been reported in the recent years, and a possible role of oxyradical toxicity hypothesized; an additional prooxidant stressor is the exposure to light and in particular to UV radiation which may become relevant for marine organisms after the stratospheric ozone depletion. The antioxidant efficiency has been characterized in both the species by analyzing the main individual antioxidants and integrating these data with the measurement of total oxyradical scavenging capacity toward hydroxyl radicals, peroxyl radicals and peroxynitrite. Seasonal fluctuations have been determined and related to variations of both biological and environmental factors. The possible utility of sea urchins as sentinel organisms and their susceptibility to oxidative stress for revealing environmental disturbance have been further confirmed in preliminary laboratory experiments from variations of antioxidant responses to temperature and UV irradiance. Key words: bioindicator, echinoderms, oxidative stress, temperature |
