title: Sublethal effects of CuO nanoparticles on Mozambique tilapia (Oreochromis mossambicus) are modulated by environmental salinity.
abstract: The increasing use of manufactured nanoparticles (NP) in different applications has triggered the need to understand their putative ecotoxicological effects in the environment. Copper oxide nanoparticles (CuO NP) are toxic, and induce oxidative stress and other pathophysiological conditions. The unique properties of NP can change depending on the characteristics of the media they are suspended in, altering the impact on their toxicity to aquatic organisms in different environments. Here, Mozambique tilapia (O. mossambicus) were exposed to flame synthesized CuO NP (0.5 and 5 mg · L(-1)) in two environmental contexts: (a) constant freshwater (FW) and (b) stepwise increase in environmental salinity (SW). Sublethal effects of CuO NP were monitored and used to dermine exposure endpoints. Fish exposed to 5 mg · L(-1) CuO in SW showed an opercular ventilation rate increase, whereas fish exposed to 5 mg · L(-1) in FW showed a milder response. Different effects of CuO NP on antioxidant enzyme activities, accumulation of transcripts for metal-responsive genes, GSH ∶ GSSG ratio, and Cu content in fish gill and liver also demonstrate that additive osmotic stress modulates CuO NP toxicity. We conclude that the toxicity of CuO NP depends on the particular environmental context and that salinity is an important factor for modulating NP toxicity in fish.
authors: Department of Animal Science, University of California-Davis, Davis, California, United States of America.
authors: Fernando D
authors: FD
authors: Villarreal
authors: Department of Mechanical and Aerospace Engineering, University of California-Davis, Davis, California, United States of America.
authors: Gautom Kumar
authors: GK
authors: Das
authors: Department of Mechanical and Aerospace Engineering, University of California-Davis, Davis, California, United States of America.
authors: Aamir
authors: A
authors: Abid
authors: Department of Mechanical and Aerospace Engineering, University of California-Davis, Davis, California, United States of America.
authors: Ian M
authors: IM
authors: Kennedy
authors: Department of Animal Science, University of California-Davis, Davis, California, United States of America.
authors: Dietmar
authors: D
authors: Kültz
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000378:metabolism; D003300:Copper / Q000378:metabolism / Q000633:toxicity*; D003460:Crystallization; D004777:Environment; D005618:Fresh Water; D005786:Gene Expression Regulation / Q000187:drug effects; D005880:Gills / Q000187:drug effects / Q000201:enzymology; D005978:Glutathione / Q000378:metabolism; D008099:Liver / Q000187:drug effects / Q000201:enzymology; D053758:Nanoparticles / Q000633:toxicity* / Q000648:ultrastructure; D010316:Particle Size; D054712:Salinity; D055672:Static Electricity; D013312:Stress, Physiological / Q000187:drug effects / Q000235:genetics; D017210:Tilapia / Q000235:genetics / Q000502:physiology*
chemical_list: D000975:Antioxidants; D003300:Copper; D005978:Glutathione; C030973:cupric oxide