title: The effect of seasonality on oxidative metabolism in Nacella (Patinigera) magellanica.
abstract: 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+/-0.02 micromol O2 h-1 g-1; summer: 0.31+/-0.06 micromol O2 h-1 g-1). Oxidative stress was assessed at the hydrophilic level as the ascorbyl radical content/ascorbate content ratio (A./AH-). The A./AH- ratio showed minimum values in winter (3.7+/-0.2 10(-5)AU) and increased in summer (18+/-5 10(-5) AU). A similar pattern was observed for lipid radical content (122+/-29 pmol mg-1 fresh mass [FW] in winter and 314+/-45 pmol mg-1 FW in summer), iron content (0.99+/-0.07 and 2.7+/-0.6 nmol mg-1 FW in winter and summer, respectively) and catalase activity (2.9+/-0.2 and 7+/-1 U 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.
authors.affiliation: Centro Austral de Investigaciones Científicas (CADIC-CONICET) c.c. 92 (9410) Ushuaia, Tierra del Fuego, Argentina.
authors.forename: Gabriela
authors.initials: G
authors.lastname: Malanga
authors.forename: María Susana
authors.initials: MS
authors.lastname: Estevez
authors.forename: Jorge
authors.initials: J
authors.lastname: Calvo
authors.forename: Doris
authors.initials: D
authors.lastname: Abele
authors.forename: Susana
authors.initials: S
authors.lastname: Puntarulo
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000378:metabolism; D001835:Body Weight; D002374:Catalase / Q000378:metabolism; D004064:Digestive System / Q000378:metabolism*; D004578:Electron Spin Resonance Spectroscopy; D004798:Enzymes / Q000378:metabolism; D005609:Free Radicals / Q000378:metabolism; D049851:Gastropoda / Q000378:metabolism* / Q000502:physiology; D015227:Lipid Peroxidation; D018384:Oxidative Stress; D010100:Oxygen / Q000378:metabolism; D012621:Seasons
chemical_list: D000975:Antioxidants; D004798:Enzymes; D005609:Free Radicals; D002374:Catalase; D010100:Oxygen