title: Pure anatase and rutile + anatase nanoparticles differently affect wheat seedlings.
abstract: TiO2-nanoparticles (TiO2-NPs) are increasingly released to the environment. The present work investigates the cytotoxicity, genotoxicity and uptake of TiO2-NPs in Triticum aestivum. Wheat seeds were exposed to 5-150 mg L(-1) of anatase (ana) or rutile + anatase (rut + ana) TiO2-NPs for 5 d. After exposure, germination and growth rates were determined. Cytotoxic effects were evaluated by changes in the cell cycle dynamics and in the membrane integrity. Genotoxicity was assessed by ploidy mutations and DNA-damage, and by mitotic abnormalities. NP uptake was analyzed by Energy Dispersive X-ray Spectroscopy (EDS). Ana-TiO2 revealed higher toxicity regarding the rate of germination, but no negative effects were detected concerning growth. Although roots and shoots showed no EDS-detectable levels of Ti, despite cyto- and genotoxicity was observed in ana and rut + ana-NPs exposed roots. Cell cycle profile was formulation dependent with rut + ana presenting a higher capability to induce a cell cycle arrest at G0/G1. Both formulations induced genotoxic effects by increasing micronucleated cells: for rut + ana a dose-dependent response is evident and seems to be more genotoxic than ana at lower concentrations. Rut + ana also increased membrane permeability. The observed higher cytotoxicity of rut + ana may be explained by the higher photoactivity of this mixture. Overall, these data indicate that during germination, TiO2-NPs induce severe cyto/genotoxic effects, which are dependent on the TiO2-NP formulation.
authors.affiliation: Department of Biology and CESAM, Laboratory of Biotechnology & Cytomics, University of Aveiro, 3810-193 Aveiro, Portugal. Electronic address: soniasilva@ua.pt.
authors.forename: Sónia
authors.initials: S
authors.lastname: Silva
authors.affiliation: Department of Biology and CESAM, Laboratory of Biotechnology & Cytomics, University of Aveiro, 3810-193 Aveiro, Portugal. Electronic address: holiveira@ua.pt.
authors.forename: Helena
authors.initials: H
authors.lastname: Oliveira
authors.affiliation: Department of Biology and GeoBioTec Research Unit, University of Aveiro, 3810-193 Aveiro, Portugal. Electronic address: scraveiro@ua.pt.
authors.forename: Sandra C
authors.initials: SC
authors.lastname: Craveiro
authors.affiliation: Department of Biology and GeoBioTec Research Unit, University of Aveiro, 3810-193 Aveiro, Portugal. Electronic address: acalado@ua.pt.
authors.forename: António J
authors.initials: AJ
authors.lastname: Calado
authors.affiliation: Department of Biology, Faculty of Sciences & GreenUP / CITAB - UP, University of Porto, Rua Campo Alegre, 4169-007 Porto, Portugal. Electronic address: csantos@fc.up.pt.
authors.forename: Conceição
authors.initials: C
authors.lastname: Santos
mesh_terms: D002453:Cell Cycle / Q000187:drug effects; D002463:Cell Membrane Permeability / Q000187:drug effects; D004249:DNA Damage; D004785:Environmental Pollutants / Q000633:toxicity*; D018525:Germination / Q000187:drug effects; D009154:Mutation; D053758:Nanoparticles / Q000633:toxicity*; D018517:Plant Roots / Q000187:drug effects / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D036226:Seedlings / Q000187:drug effects / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D013052:Spectrometry, X-Ray Emission; D014025:Titanium / Q000633:toxicity*; D014908:Triticum / Q000187:drug effects* / Q000235:genetics / Q000254:growth & development / Q000378:metabolism
chemical_list: D004785:Environmental Pollutants; C009495:titanium dioxide; D014025:Titanium
keywords: Cell cycle; Micronucleus test; Nanoparticles; Titanium dioxide; Toxicity; Wheat