Lipid radical generation in polar (Laternula elliptica) and temperate (Mya arenaria) bivalves.
Lipid peroxidation in Laternula elliptica was assessed by detecting lipid radicals by electronic paramagnetic resonance. The values were compared with data from the temperate mud clam Mya arenaria. Lipid radical content was higher in the Antarctic bivalve than in the temperate mud clam, even within the range of its habitat temperature. The rate of generation of lipid radicals was affected by the iron content in the samples. The iron content in individual samples of digestive glands in L. elliptica ranged from 3 to 6 nmol g(-1) fresh weight (fwt) and in M. arenaria from 0.6 to 2.7 nmol g(-1) fwt. Arrhenius plots, developed from the rates obtained in the presence of 25 microM iron, showed no significant differences between the activation energy calculated for digestive glands of L. elliptica and M. arenaria. The Fe3+ reduction rate in L. elliptica was higher than in M. arenaria (4.7 +/- 0.9 vs. 1.8 +/- 0.4 nmol mg(-1) protein min(-1), respectively). L. elliptica had a higher content of alpha-tocopherol and beta-carotene than M. arenaria. Our data suggest that increased lipid radical content in the membranes of cold-adapted organisms could be related to iron content.
Susana Estevez
Maria
M
Physical Chemistry-PRALIB, School of Pharmacy and Biochemistry, University of Buenos Aires, Junín 956, 1113, Buenos Aires, Argentina.
Abele
Doris
D
Puntarulo
Susana
S
D000818:Animals; D000864:Antarctic Regions; D000975:Antioxidants / Q000378:metabolism; D049872:Bivalvia / Q000378:metabolism*; D002374:Catalase / Q000378:metabolism; D004064:Digestive System / Q000378:metabolism; D004777:Environment; D005609:Free Radicals / Q000378:metabolism*; D005858:Germany; D007501:Iron / Q000378:metabolism; D050356:Lipid Metabolism; D015227:Lipid Peroxidation; D008055:Lipids / Q000737:chemistry; D010084:Oxidation-Reduction; D013696:Temperature
D000975:Antioxidants; D005609:Free Radicals; D008055:Lipids; D007501:Iron; D002374:Catalase