title: Enzymatic biomarkers can portray nanoCuO-induced oxidative and neuronal stress in freshwater shredders.
abstract: Commercial applications of nanometal oxides have increased concern about their release into natural waters and consequent risks to aquatic biota and the processes they drive. In forest streams, the invertebrate shredder Allogamus ligonifer plays a key role in detritus food webs by transferring carbon and energy from plant litter to higher trophic levels. We assessed the response profiles of oxidative and neuronal stress enzymatic biomarkers in A. ligonifer after 96h exposure to nanoCuO at concentration ranges <LC30. To better understand the contribution of ionic form in nanoCuO-induced stress, Cu2+released from nanoCuO was quantified and the enzymatic responses to Cu2+exposure at similar effective concentrations were compared. The highest activities of superoxide dismutase (SOD), glutathione peroxidase (GPx) and glutathione reductase (GR) were observed at concentrations <LC5. The enzymatic activities decreased at effective concentrations between LC10and LC30. GR activity remained higher than in control at all concentrations. The activity of glutathione S-transferase (GST) increased whereas that of catalase (CAT) decreased at concentrations between LC10and LC30. The response patterns suggested that antioxidant enzymes could prevent oxidative stress at low concentrations (<LC10) of nanoCuO, thereby contributing to the survival of A. ligonifer. At concentrations between LC10and LC30, effects of nanoparticulate or released ionic copper on enzyme activities were concentration-dependent, and led to oxidative stress and even to animal death. The activity of acetylcholinesterase (AChE) was strongly inhibited even at concentrations <LC10, suggesting neuronal stress in A. ligonifer.
authors.affiliation: Centre of Molecular and Environmental Biology (CBMA), Department of Biology, University of Minho, Campus of Gualtar, 4710-057 Braga, Portugal; Institute of Science and Innovation for Bio-Sustainability (IB-S), University of Minho, Campus of Gualtar, 4710-057 Braga, Portugal. Electronic address: arunava@bio.uminho.pt.
authors.forename: Arunava
authors.initials: A
authors.lastname: Pradhan
authors.affiliation: Centre of Molecular and Environmental Biology (CBMA), Department of Biology, University of Minho, Campus of Gualtar, 4710-057 Braga, Portugal.
authors.forename: Carla O
authors.initials: CO
authors.lastname: Silva
authors.affiliation: Centre of Chemistry, Department of Chemistry, University of Minho, Campus of Gualtar, 4710-057 Braga, Portugal.
authors.forename: Carlos
authors.initials: C
authors.lastname: Silva
authors.affiliation: Centre of Molecular and Environmental Biology (CBMA), Department of Biology, University of Minho, Campus of Gualtar, 4710-057 Braga, Portugal; Institute of Science and Innovation for Bio-Sustainability (IB-S), University of Minho, Campus of Gualtar, 4710-057 Braga, Portugal.
authors.forename: Cláudia
authors.initials: C
authors.lastname: Pascoal
authors.affiliation: Centre of Molecular and Environmental Biology (CBMA), Department of Biology, University of Minho, Campus of Gualtar, 4710-057 Braga, Portugal; Institute of Science and Innovation for Bio-Sustainability (IB-S), University of Minho, Campus of Gualtar, 4710-057 Braga, Portugal.
authors.forename: Fernanda
authors.initials: F
authors.lastname: Cássio
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000378:metabolism; D015415:Biomarkers / Q000378:metabolism; D003300:Copper / Q000633:toxicity*; D004305:Dose-Response Relationship, Drug; D005618:Fresh Water; D005979:Glutathione Peroxidase / Q000378:metabolism; D005980:Glutathione Reductase / Q000378:metabolism; D007313:Insecta / Q000187:drug effects* / Q000201:enzymology* / Q000502:physiology; D007448:Invertebrates / Q000378:metabolism; D053768:Metal Nanoparticles / Q000633:toxicity*; D009474:Neurons / Q000201:enzymology; D018384:Oxidative Stress / Q000187:drug effects / Q000502:physiology; D013312:Stress, Physiological / Q000187:drug effects* / Q000502:physiology; D013482:Superoxide Dismutase / Q000378:metabolism; D018675:Toxicity Tests; D014874:Water Pollutants, Chemical / Q000633:toxicity*
chemical_list: D000975:Antioxidants; D015415:Biomarkers; D014874:Water Pollutants, Chemical; D003300:Copper; D005979:Glutathione Peroxidase; D013482:Superoxide Dismutase; D005980:Glutathione Reductase; C030973:cupric oxide
keywords: Biomarkers; Cu(2+); Freshwater invertebrate shredder; NanoCuO; Oxidative and neuronal stress