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This study presents the toxicological effects of iron nanoparticles (NP Fe2O3) using in vitro and in vivo tests. Initially nanoparticles were characterized physic-chemically followed by evaluation of cell viability using different cell lines. Allium cepa test and comet assay (cell lines and Danio rerio) were used for evaluation of genotoxicity. Oxidative stress analyses were performed using D. rerio exposed to NP-Fe2O3, and the enzymatic activity of the enzymes catalase (CAT), glutathione peroxidase (GPx) and glutathione S-transferase (GST) were evaluated. The results showed that initially nanoparticles had 65.55 nm, 0.24 of polydispersity of and 11.4 mV of zeta potential. Regarding cell viability, it was observed that this did not reach the IC50 up to the concentration 1 x 1010 NP mL-1. The in vitro comet assay showed that in concentrations 1.96 x108 and 109 NPs mL-1 these presented toxicity, for Allium cepa evaluation in concentrations 19.6 and 39.0 x109 NPs mL-1 presented significant damages when compared to the control. Oxidative stress showed that the liver was the most affected organ when compared to the control. Although studies show that iron nanoparticles do not lead to changes, further studies are needed to make sure they do not lead to environmental changes.

Made available in DSpace on 2019-10-03T17:31:19Z (GMT). No. of bitstreams: 0 Previous issue date: 2018-09-01 This study presents the toxicological effects of iron nanoparticles (NP Fe2O3) using in vitro and in vivo tests. Initially nanoparticles were characterized physic-chemically followed by evaluation of cell viability using different cell lines. Allium cepa test and comet assay (cell lines and Danio rerio) were used for evaluation of genotoxicity. Oxidative stress analyses were performed using D. rerio exposed to NP-Fe2O3, and the enzymatic activity of the enzymes catalase (CAT), glutathione peroxidase (GPx) and glutathione S-transferase (GST) were evaluated. The results showed that initially nanoparticles had 65.55 nm, 0.24 of polydispersity of and 11.4 mV of zeta potential. Regarding cell viability, it was observed that this did not reach the IC50 up to the concentration 1 x 1010 NP mL-1. The in vitro comet assay showed that in concentrations 1.96 x108 and 109 NPs mL-1 these presented toxicity, for Allium cepa evaluation in concentrations 19.6 and 39.0 x109 NPs mL-1 presented significant damages when compared to the control. Oxidative stress showed that the liver was the most affected organ when compared to the control. Although studies show that iron nanoparticles do not lead to changes, further studies are needed to make sure they do not lead to environmental changes. Universidade Federal de São Carlos Departamento de Biologia Universidade de Sorocaba Departamento de Biotecnologia Universidade Estadual de São Paulo Departamento de Engenharia Ambiental

A análise in vivo da taxa de assimilação líquida de CO2 (A) em resposta à densidade de fluxo de fótons fotossinteticamente ativos (DFFFA) e em resposta à concentração intercelular de CO2 da folha (Ci) permite uma avaliação detalhada do processo fotossintético. Com as curvas A/DFFFA, se estabelece a DFFFA máxima, em que a maior parte da energia absorvida é transferida para a formação de produtos fotoquímicos. Já com as curvas A/Ci, calculou-se a velocidade máxima de carboxilação da Rubisco (Vc,max) de 89,3 µmol m-2 s-1, a velocidade máxima de oxigenação da Rubisco (Vo,max) de 24,7 µmol m-2 s-1, a velocidade máxima de transporte de elétrons (Jmax) de 159,8 µmol m-2 s-1, do qual a regeneração de RuBP é dependente, a respiração mitocondrial (Rd) de 0,88 µmol m-2 s-1, e a condutância mesofílica (g m) de 0,47 mol m-2 s-1, para o feijoeiro comum cultivado no Brasil (Phaseolus vulgaris var. mexicanus). The in vivo analysis of net CO2 assimilation rate (A) versus active photosynthetic photon flux density (DFFFA) and versus intercellular CO2 concentration (Ci), allows a more detailed evaluation of the photosynthetic process. The A/DFFFA curve can be used to establish the maximal DFFFA in which the absorbed light energy is quenched in the formation of photochemical products. Using the A/Ci curves, it was calculated the maximum rates of Rubisco carboxilation (Vc,max) of 89.3 µmol m-2 s-1, the maximum rates of Rubisco oxygenation (Vo,max) of 24.7 µmol m-2 s-1, the maximum rates of electron transport (Jmax) of 159.8 µmol m-2 s-1, from which the RuBP regeneration is dependent, the mitochondrial respiration (Rd) of 0.88 µmol m-2 s-1, and the mesophyll conductance (g m) of 0.47 mol m-2 s-1 for common bean cultivated in Brazil (Phaseolus vulgaris var. mexicanus).