title: Fungi from metal-polluted streams may have high ability to cope with the oxidative stress induced by copper oxide nanoparticles.
abstract: Increased commercialization of products based on metal oxide nanoparticles increases the likelihood that these nanoparticles will be released into aquatic environments, thus making relevant the assessment of their potential impacts on aquatic biota. Aquatic fungi are distributed worldwide and play a key role in organic matter turnover in freshwater ecosystems. The present study investigated the impacts of copper oxide spherical nanoparticles (CuO-NPs; <50 nm powder, 5 levels ≤200 mg/L) on cellular targets and antioxidant defenses in 5 fungal isolates collected from metal-polluted or nonpolluted streams. The CuO-NPs induced oxidative stress in aquatic fungi, as evidenced by intracellular accumulation of reactive oxygen species, and led to plasma membrane damage and DNA strand breaks in a concentration-dependent manner. Effects were more pronounced with a longer exposure time (3 d vs 10 d). Under CuO-NP exposure, mycelia of fungi collected from metal-polluted streams showed less oxidative stress and higher activities of superoxide dismutase and glutathione reductase compared with fungi from nonpolluted streams. The latter fungi responded to CuO-NPs with a stronger stimulation of glutathione peroxidase activity. These findings may indicate that fungi isolated from metal-polluted streams had a greater ability to maintain the pool of reduced glutathione than those from nonpolluted streams. Overall, results suggest that populations adapted to metals may develop mechanisms to cope with the oxidative stress induced by metal nanoparticles.
authors.affiliation: Centre of Molecular and Environmental Biology, Department of Biology, University of Minho, Campus of Gualtar, Braga, Portugal.
authors.forename: Arunava
authors.initials: A
authors.lastname: Pradhan
authors.forename: Sahadevan
authors.initials: S
authors.lastname: Seena
authors.forename: Dietmar
authors.initials: D
authors.lastname: Schlosser
authors.forename: Katharina
authors.initials: K
authors.lastname: Gerth
authors.forename: Stefan
authors.initials: S
authors.lastname: Helm
authors.forename: Melanie
authors.initials: M
authors.lastname: Dobritzsch
authors.forename: Gerd-Joachim
authors.initials: GJ
authors.lastname: Krauss
authors.forename: Dirk
authors.initials: D
authors.lastname: Dobritzsch
authors.forename: Cláudia
authors.initials: C
authors.lastname: Pascoal
authors.forename: Fernanda
authors.initials: F
authors.lastname: Cássio
mesh_terms: D000975:Antioxidants / Q000378:metabolism; D002462:Cell Membrane / Q000187:drug effects; D003300:Copper / Q000633:toxicity*; D004249:DNA Damage; D005618:Fresh Water / Q000382:microbiology; D005658:Fungi / Q000187:drug effects* / Q000378:metabolism; D053768:Metal Nanoparticles / Q000633:toxicity*; D008670:Metals / Q000633:toxicity*; D025282:Mycelium / Q000187:drug effects; D018384:Oxidative Stress / Q000187:drug effects*; D017382:Reactive Oxygen Species / Q000378:metabolism; D014871:Water Microbiology; D014874:Water Pollutants, Chemical / Q000633:toxicity*
chemical_list: D000975:Antioxidants; D008670:Metals; D017382:Reactive Oxygen Species; D014874:Water Pollutants, Chemical; D003300:Copper; C030973:cupric oxide
keywords: Antioxidant enzymes; CuO-NPs; DNA strand breaks; Plasma membrane disruption; Reactive oxygen species accumulation