Fe effects on the oxidative and nitrosative metabolism in the Antarctic limpet Nacella concinna

GONZÁLEZ PAULA M.; PUNTARULO S.

La Paz

Conferencia; Second International Conference on Oxidative Stress in Aquatic Ecosystems; 2015

Centro de Investigaciones Biológicas del Noroeste

Limpetsbrowse on micro and macroalgae ingesting particulate and dissolved Fe togetherwith food particles. In this work we investigated Fe cellular distribution, andthe FE-dependent oxidative and nitrosative metabolism in the digestive gland (DG)of two limpet populations (intertidal and subtidal, with intermittent andconstant natural Fe exposure, respectively) of the Antarctic species Nacella concinna. Total Fe content(measured by spectrophotometry) and labile Fe pool (measured by electronicparamagnetic resonance, EPR and spectrofluorometry) was significantly higher inthe DG of the subtidal population as compared to the intertidal one. Nodifferences between populations were seen on the content of Fe atoms onisolated ferritin. Ascorbyl radical generation (measured by EPR) was 2.0±0.4 and 6.5±0.8 pmol/mg FW in the DG of the intertidal andsubtidal populations, respectively. Lipid damage (measured as thiobarbituricacid reactive substances) was significantly different between the tissues ofintertidal and subtidal samples, 491±102 and 1242±367 pmol/mg FW, respectively. Antioxidant enzymes,catalase and superoxide dismutase, were evaluated spectrophotometrically and nodifferences were found between the limpets. Nitric oxide (NO) content (analyzedby EPR) was 25±3 and22±2 pmol/mgFW in DG from intertidal and subtidal animals, respectively. NO synthase(NOS-like) was evaluated supplementing the samples with the enzyme co-factors, andthe inhibitory effect of Nω-nitro-L-arginine methyl ester hydrochloride wastested. NO generation rate was 3.4±0.3 and 4.7±0.6 pmol/min mg FW in the intertidal and subtidalDG, respectively. These results showed that the limpet population constantlycovered by the Fe enrich water is the most affected population in both thehidrophylic and lipophilic cellular compartments. The nitrosative metabolismappears not to be related to Fe-dependent oxidative metabolism.