INSTITUTO DE BIOQUIMICA Y MEDICINA MOLECULAR PROFESOR ALBERTO BOVERIS
Unidad Ejecutora - UE
capítulos de libros
The use of electron paramagnetic resonance (EPR) in the study of oxidative damage to lipids in aquatic systems
MALANGA G.; PUNTARULO S.
Oxidative stress in aquatic ecosystems
Oxidative damage to lipids depends on the nature of the oxidant, the type of lipid, and the severity of the oxidation. Since a variety of stable products are formed, several assays have been developed over the years to assess these products in order to evaluate lipid peroxidation. Electron paramagnetic resonance (EPR) spectroscopy has shown the capacity of detecting, in the presence of exogenous traps, the presence of the lipid radicals formed during peroxidation, by yielding unique and stable products. Thus, even though EPR detection of lipid radicals could be considered a finger-print of radical presence, spin trapping studies cannot really distinguish among peroxyl (ROO), alcohoxyl (RO) and alkyl (R) adducts owing to the similarity of the corresponding coupling constants. Over the last decade our laboratory has applied this methodology to a wide range of aquatic systems including algae, sea urchin, limpets and bivalves, under physiological and oxidative stress conditions as well. EPR-sensitive adduct formation correlates well with cell membrane damage, as measured by the TBARS, but no interference with other biological compounds was observed. Although probe instability, tissue metabolism, lack of spin specificity are drawback factors for employing EPR for the in vivo determination of free radicals, the dependability of this technique, mostly by combining it with other biochemical strategies, drastically enhance the value of these procedures. Future studies are required to further adapt this methodology to study oxidative damage to lipids in different types of biological marine materials, such as suspension cells, tissue or organs.