title: Ecotoxicological studies of micro- and nanosized barium titanate on aquatic photosynthetic microorganisms.
abstract: The interaction between live organisms and micro- or nanosized materials has become a current focus in toxicology. As nanosized barium titanate has gained momentum lately in the medical field, the aims of the present work are: (i) to assess BT toxicity and its mechanisms on the aquatic environment, using two photosynthetic organisms (Anabaena flos-aquae, a colonial cyanobacteria, and Euglena gracilis, a flagellated euglenoid); (ii) to study and correlate the physicochemical properties of BT with its toxic profile; (iii) to compare the BT behavior (and Ba(2+) released ions) and the toxic profile in synthetic (Bold's Basal, BB, or Mineral Medium, MM) and natural culture media (Seine River Water, SRW); and (iv) to address whether size (micro, BT MP, or nano, BT NP) is an issue in BT particles toxicity. Responses such as growth inhibition, cell viability, superoxide dismutase (SOD) activity, adenosine-5-triphosphate (ATP) content and photosynthetic efficiency were evaluated. The main conclusions are: (i) BT have statistically significant toxic effects on E. gracilis growth and viability even in small concentrations (1μgmL(-1)), for both media and since the first 24 h; on the contrary of on A. flos-aquae, to whom the effects were noticeable only for the higher concentrations (after 96 h: ≥75 μg mL(-1) for BT NP and =100 μg mL(-1) for BT MP, in BB; and ≥75 μg mL(-1) for both materials in SRW), in spite of the viability being affected in all concentrations; (ii) the BT behaviors in synthetic and natural culture media were slightly different, being the toxic effects more pronounced when grown in SRW - in this case, a worse physiological state of the organisms in SRW can occur and account for the lower resistance, probably linked to a paucity of nutrients or even a synergistic effect with a contaminant from the river; and (iii) the effects seem to be mediated by induced stress without a direct contact in A. flos-aquae and by direct endocytosis in E. gracilis, but in both organisms the contact with both BT MP and BT NP increased SOD activity and decreased photosynthetic efficiency and intracellular ATP content; and (iv) size does not seem to be an issue in BT particles toxicity since micro- and nano-particles produced significant toxic for the model-organisms.
authors.affiliation: Universidade Federal de Juiz de Fora, Núcleo de Pesquisa e Inovação em Ciências da Saúde (NUPICS), Rua José Lourenço Kelmer, s/n, 36036-900 Juiz de Fora, Brazil. Electronic address: h.c.polonini@gmail.com.
authors.forename: Hudson C
authors.initials: HC
authors.lastname: Polonini
authors.affiliation: Empresa Brasileira de Pesquisa Agropecuária (Embrapa Gado de Leite), 36038-330 Juiz de Fora, Brazil.
authors.forename: Humberto M
authors.initials: HM
authors.lastname: Brandão
authors.affiliation: Universidade Federal de Juiz de Fora, Núcleo de Pesquisa e Inovação em Ciências da Saúde (NUPICS), Rua José Lourenço Kelmer, s/n, 36036-900 Juiz de Fora, Brazil.
authors.forename: Nádia R B
authors.initials: NR
authors.lastname: Raposo
authors.affiliation: Université Paris Diderot, Sorbonne Paris Cité, Interfaces, Traitements, Organisation et Dynamique des Systèmes (ITODYS), UMR 7086, CNRS, 15 rue Jean de Baïf, F-75205 Paris Cedex 13, France.
authors.forename: Ludovic
authors.initials: L
authors.lastname: Mouton
authors.affiliation: Muséum National d'Histoire Naturelle, Département RDDM, USM 505, 57 rue Cuvier, F-75005 Paris, France.
authors.forename: Claude
authors.initials: C
authors.lastname: Yéprémian
authors.affiliation: Muséum National d'Histoire Naturelle, Département RDDM, USM 505, 57 rue Cuvier, F-75005 Paris, France.
authors.forename: Alain
authors.initials: A
authors.lastname: Couté
authors.affiliation: Université Paris Diderot, Sorbonne Paris Cité, Interfaces, Traitements, Organisation et Dynamique des Systèmes (ITODYS), UMR 7086, CNRS, 15 rue Jean de Baïf, F-75205 Paris Cedex 13, France. Electronic address: roberta.brayner@univ-paris-diderot.fr.
authors.forename: Roberta
authors.initials: R
authors.lastname: Brayner
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D017609:Barium Compounds / Q000633:toxicity*; D046869:Dolichospermum flos-aquae / Q000187:drug effects* / Q000201:enzymology / Q000648:ultrastructure; D054750:Ecotoxicology; D004789:Enzyme Activation / Q000187:drug effects; D005056:Euglena gracilis / Q000187:drug effects* / Q000201:enzymology / Q000648:ultrastructure; D005618:Fresh Water / Q000737:chemistry; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D010316:Particle Size; D010788:Photosynthesis / Q000187:drug effects; D013482:Superoxide Dismutase / Q000378:metabolism; D014025:Titanium / Q000633:toxicity*; D014874:Water Pollutants, Chemical / Q000633:toxicity*
chemical_list: D017609:Barium Compounds; D014874:Water Pollutants, Chemical; C024547:barium titanate(IV); D000255:Adenosine Triphosphate; D014025:Titanium; D013482:Superoxide Dismutase
keywords: Barium titanate; Ecotoxicology; Nanoparticles