title: Worms from the Arctic are better adapted to freezing and high salinity than worms from temperate regions: oxidative stress responses in Enchytraeus albidus.
abstract: Enchytraeus albidus is a freeze-tolerant enchytraeid found in diverse habitats, from supra-littoral to terrestrial, and spanning temperate to arctic regions. Thus, this worm is often exposed to sub-zero temperatures and fluctuating salinity regimes that can lead to physiological stress. We therefore studied the oxidative stress by measuring lipid peroxidation, anti-oxidant defenses and neurotransmission activity in E. albidus from arctic (Greenland) and temperate (Germany) regions during a short-term exposure to saline conditions (0, 15, 35 and 50‰ NaCl) and low temperatures (+2, -2 and -5 °C). Various enzymatic and non-enzymatic oxidative stress markers were analyzed. Results have shown that both salt and freezing caused oxidative stress in E. albidus, particularly from Germany, as confirmed by catalase, glutathione-S-transferase and superoxide dismutase activities and lipid peroxidation levels. Neurotransmission (as judged from acetylcholinesterase activity) was reduced by saline conditions at +2 °C, but stimulated at -2 and -5 °C. Worms from Greenland had relatively higher and more stable levels of antioxidants than worms from Germany, reflecting their higher tolerance of freezing and saline conditions.
authors.affiliation: Department of Biology and CESAM (Centre for Environmental and Marine Studies), University of Aveiro, 3810-193 Aveiro, Portugal. Electronic address: ana.luisa.silva@ua.pt.
authors.forename: A L Patrício
authors.initials: AL
authors.lastname: Silva
authors.forename: M
authors.initials: M
authors.lastname: Holmstrup
authors.forename: M J B
authors.initials: MJ
authors.lastname: Amorim
mesh_terms: D000064:Acclimatization; D000110:Acetylcholinesterase / Q000378:metabolism; D000818:Animals; D000975:Antioxidants / Q000378:metabolism; D001110:Arctic Regions; D002374:Catalase / Q000378:metabolism; D005615:Freezing; D005858:Germany; D005982:Glutathione Transferase / Q000378:metabolism; D006116:Greenland; D015227:Lipid Peroxidation; D009835:Oligochaeta / Q000502:physiology*; D018384:Oxidative Stress; D054712:Salinity; D013482:Superoxide Dismutase / Q000378:metabolism
chemical_list: D000975:Antioxidants; D002374:Catalase; D013482:Superoxide Dismutase; D005982:Glutathione Transferase; D000110:Acetylcholinesterase
keywords: Antioxidants; Biomarkers; Enchytraeids; Natural stressors; Oxidative stress