Ferritin and Labile Iron Pool in Limpets from the Beagle Channel

. GONZALEZ P.M., MALANGA G. Y PUNTARULO S.

Aquatic Toxicology Research Focus

Año: 2008; p. 177 - 188

The aim of this work was to study Fe localization and Fe-dependent reactions in digestive glands of two sub-Antarctic limpets Nacella (P.) magellanica and Nacella (P.) deaurata. In spite of living in the same area, the difference in shore level location affects animal exposure to aerial and environmental conditions. The intertidal species (N. (P.) magellanica) is subjected to a variety of stress not experienced by N. (P.) deaurata; however N. deaurata would be exposed to seawater Fe for longer periods than N. (P.) magellanica. Total Fe content in digestive glands was 1.99 ± 0.03 and 0.99 ± 0.07 nmol/mg FW for N. (P.) deaurata and N. (P.) magellanica, respectively. Lipid radical content was assessed by electronic paramagnetic resonance (EPR), and was higher for N. (P.) deaurata than for N. (P.) magellanica (192 ± 31 and 122 ± 29 pmol/mg FW, respectively). The labile Fe pool (LIP), assessed by two different techniques, did not showed any difference between both species. Ferritin (Ft) was extracted from digestive glands, purified in a Sephacryl-S-300 column, and the protein was identified by SDS-PAGE. A significantly different Ft content in both species (22.9 and 6.17 ng/mg FW for N. (P.) deaurata and N. (P.) magellanica, respectively) was observed. The Fe content per molecule of Ft did not show any difference between the species. These results suggest that the Fe excess is efficiently stored in the Ft in N. (P.) deaurata since the LIP is not different between species even though N. (P.) deaurata showed a higher content of both Fe and Ft, than N. (P.) magellanica. However, other mechanisms could be operative in making Fe available for the catalysis of free radical reactions under stress conditions since lipid radical content was higher in N. (P.) deaurata as compared to N. (P.) magellanica.