Iron and Radical Content in Mya arenaria. Possible Sources of NO Generation

GONZALEZ P.M., ABELE D. Y PUNTARULO S.

Aquat. Toxicol.

Año: 2008 vol. 89 p. 122 - 128

The main objective of this work was to analyze oxidative metabolism in Mya arenaria for interspecific comparisons. Total Fe content in M. arenaria collected in the German Wadden Sea was 1.9±0.7, 0.7±0.1 and 0.17±0.01 nmol/mg FW, in digestive glands (DG), mantle and gills, respectively. Labile Fe pool, assessed by electronic paramagnetic resonance (EPR), was 146±10 pmol/mg FW, and by the fluorescence method employing calcein was 118±9 pmol/mg FW. The lipid radical content in the DG, assessed by EPR, was 37±1 pmol/mg FW, and the thiobarbituric reactive substances content amounted to 57±8 nmol/mg FW. Ascorbyl radical (A·) content, assessed by quantification of EPR signals, was 0.04±0.01 pmol/mg FW, and the ascorbate content (AH-) was 478±12 pmol/mg FW. The ratio A·/AH- was (8±1) 10-5 AU, suggesting a minimum oxidative stress even under physiological conditions, presumably depending on basal metabolic functions. The content of nitric oxide (NO), assessed by EPR, was 99±3 pmol/mg FW. The generation rate of NO by nitric oxide synthase-like activity (NOS-like) was assayed as NO production detected by EPR in the presence of arginine and NADPH, and was 3.16±0.06 pmol/mg FW/min. The data presented here document the presence of highly reactive species in M. arenaria in summer, when water temperatures and the metabolic activity of the bivalve are higher than over the rest of the year.