Seasonality effect on oxidative metabolism in Nacella (P.) magellanica.

GABRIELA FABIANA MALANGA; SUSANA ESTEVEZ; JORGE CALVO; DORIS ABELE; SUSANA PUNTARULO

COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY A-MOLECULAR AND INTEGRATIVE PHYSIOLOGY

Año: 2007 vol. 146 p. 551 - 558

1095-6433

We studied the seasonal variation on aerobic metabolism and the response of oxidative stress parameters in the digestive glands of the subpolar limpet Nacella (P.) magellanica. Sampling was carried out from July (winter) 2002 to July 2003 in Beagle Channel, Tierra del Fuego, Argentina. Whole animal respiration rates increased in early spring as the animals spawned and remained elevated throughout summer and fall (winter: 0.09± 0.02ìmol O2 h−1 g−1; summer: 0.31±0.06ìmol O2 h−1 g−1). Oxidative stress was assessed at the hydrophilic level as the ascorbyl radical content / ascorbate content ratio (AU/AH−). The AU/AH− ratio showed minimum values in winter (3.7±0.2 10−5AU) and increased in summer (18±5 10−5AU). A similar pattern was observed for lipid radical content (122±29pmol mg−1 fresh mass [FW] in winter and 314±45pmol mg−1 FW in summer), iron content (0.99±0.07 and 2.7±0.6nmol mg−1 FWin winter and summer, respectively) and catalase activity (2.9±0.2 and 7±1U mg−1Nacella (P.) magellanica. Sampling was carried out from July (winter) 2002 to July 2003 in Beagle Channel, Tierra del Fuego, Argentina. Whole animal respiration rates increased in early spring as the animals spawned and remained elevated throughout summer and fall (winter: 0.09± 0.02ìmol O2 h−1 g−1; summer: 0.31±0.06ìmol O2 h−1 g−1). Oxidative stress was assessed at the hydrophilic level as the ascorbyl radical content / ascorbate content ratio (AU/AH−). The AU/AH− ratio showed minimum values in winter (3.7±0.2 10−5AU) and increased in summer (18±5 10−5AU). A similar pattern was observed for lipid radical content (122±29pmol mg−1 fresh mass [FW] in winter and 314±45pmol mg−1 FW in summer), iron content (0.99±0.07 and 2.7±0.6nmol mg−1 FWin winter and summer, respectively) and catalase activity (2.9±0.2 and 7±1U mg−1ìmol O2 h−1 g−1; summer: 0.31±0.06ìmol O2 h−1 g−1). Oxidative stress was assessed at the hydrophilic level as the ascorbyl radical content / ascorbate content ratio (AU/AH−). The AU/AH− ratio showed minimum values in winter (3.7±0.2 10−5AU) and increased in summer (18±5 10−5AU). A similar pattern was observed for lipid radical content (122±29pmol mg−1 fresh mass [FW] in winter and 314±45pmol mg−1 FW in summer), iron content (0.99±0.07 and 2.7±0.6nmol mg−1 FWin winter and summer, respectively) and catalase activity (2.9±0.2 and 7±1U mg−1U/AH−). The AU/AH− ratio showed minimum values in winter (3.7±0.2 10−5AU) and increased in summer (18±5 10−5AU). A similar pattern was observed for lipid radical content (122±29pmol mg−1 fresh mass [FW] in winter and 314±45pmol mg−1 FW in summer), iron content (0.99±0.07 and 2.7±0.6nmol mg−1 FWin winter and summer, respectively) and catalase activity (2.9±0.2 and 7±1U mg−1−5AU). A similar pattern was observed for lipid radical content (122±29pmol mg−1 fresh mass [FW] in winter and 314±45pmol mg−1 FW in summer), iron content (0.99±0.07 and 2.7±0.6nmol mg−1 FWin winter and summer, respectively) and catalase activity (2.9±0.2 and 7±1U mg−1−1 FWin winter and summer, respectively) and catalase activity (2.9±0.2 and 7±1U mg−1 FW in winter and summer, respectively). Since nitrogen derived radicals are thought to be critically involved in oxidative metabolism in cells, nitric oxide content was measured and a significant difference in the content of the Fe–MGD–NO adduct in digestive glands from winter and summer animals was observed. Together, the data indicate that both oxygen and nitrogen radical generation rates in N. (P.) magellanica are strongly dependent on season.–MGD–NO adduct in digestive glands from winter and summer animals was observed. Together, the data indicate that both oxygen and nitrogen radical generation rates in N. (P.) magellanica are strongly dependent on season.N. (P.) magellanica are strongly dependent on season.