title: Mechanisms of response to silver nanoparticles on Enchytraeus albidus (Oligochaeta): survival, reproduction and gene expression profile.
abstract: Silver has antimicrobial properties and silver nanoparticles (Ag-NPs) have been some of the most widely used NPs. Information regarding their effects is still insufficient, in particular for soil dwelling organisms. The standard soil Oligochaete Enchytraeus albidus was used to study the effects of Ag in soils, using differential gene expression (microarray) and population (survival, reproduction) response to Ag-NPs (PVP coated) and AgNO₃. Results showed higher toxicity of AgNO₃ (EC₅₀<50 mg/kg) compared to toxicity of Ag-NPs (EC₅₀=225 mg/kg). Based on the biological and material identity, the difference in toxicity between Ag-NPs and AgNO₃ could possibly be explained by a release of Ag(+) ions from the particles or by a slower uptake of Ag-NPs. The indications were that the responses to Ag-NPs reflect an effect of Ag ions and Ag-NPs given the extent of similar/dissimilar genes activated. The particles characterization supports this deduction as there were limited free ions measured in soil extracts, maybe related to little oxidation and/or complexation in the soil matrix. The possibility that gene differences were due to different levels of biological impact (i.e. physiological responses) should not be excluded. Testing of Ag-NPs seem to require longer exposure period to be comparable in terms of effect/risk assessment with other chemicals.
authors: Department of Biology & CESAM, University of Aveiro, 3810-193 Aveiro, Portugal. Electronic address: susana.gomes@ua.pt.
authors: Susana I L
authors: SIL
authors: Gomes
authors: Department of Biology & CESAM, University of Aveiro, 3810-193 Aveiro, Portugal. Electronic address: asoares@ua.pt.
authors: Amadeu M V M
authors: AMVM
authors: Soares
authors: Department of Bioscience, Aarhus University, Vejlsovej 25, PO BOX 314, DK-8600 Silkeborg, Denmark. Electronic address: jsf@dmu.dk.
authors: Janeck J
authors: JJ
authors: Scott-Fordsmand
authors: Department of Biology & CESAM, University of Aveiro, 3810-193 Aveiro, Portugal. Electronic address: mjamorim@ua.pt.
authors: Mónica J B
authors: MJB
authors: Amorim
mesh_terms: D000818:Animals; D053768:Metal Nanoparticles / Q000633:toxicity*; D009835:Oligochaeta / Q000187:drug effects* / Q000502:physiology; D012098:Reproduction / Q000187:drug effects; D012834:Silver / Q000633:toxicity*; D012835:Silver Nitrate / Q000633:toxicity*; D012989:Soil Pollutants / Q000633:toxicity*; D059467:Transcriptome / Q000187:drug effects
chemical_list: D012989:Soil Pollutants; D012834:Silver; D012835:Silver Nitrate