NANOCIÊNCIA & NANOTECNOLOGIA

Nanomateriais vêm causando uma revolução na ciência, e sua aplicação na tecnologia está aumentando. Nanopartículas compreendem partículas entre 1 e 100 nanômetros (nm) de tamanho, mas este intervalo pode variar quando relativo à avaliação toxicológica. O uso extensivo e a consequente produção de resíduos de nanomateriais têm levado esses produtos químicos para o meio ambiente, o que causa possíveis contaminações. Portanto, como um assunto interdisciplinar, fez-se, aqui, uma breve revisão sobre alguns aspectos interessantes e contemporâneos da nanotecnologia, especialmente focados em ciências ambientais e da conservação.Palavras-chave: Nanomateriais. Nanotoxicologia. Ecotoxicologia. Dióxido de titânio

Piscine micronucleus test and the comet assay reveal genotoxic effects of Atrazine herbicide in the neotropical fish Rhamdia quelen

Atrazine (ATZ) is an herbicide extensively used around the world to kill weeds. Due to its applicability and benefits in farming, ATZ can easily reach the aquatic ecosystems and, therefore, represent risks for aquatic biota and human populations. The aim of this study was to evaluate the genotoxic effects of ATZ on Rhamdia quelen through the piscine micronucleus test (MNT) and the comet assay in erythrocytes (ECA) and gill cells (GCA), at three different concentrations (2, 10, and 100 μg L-1) in static (SB) and semi-static bioassays (SSB) during 96 hours. In the SB, we observed an increased frequency of nuclear morphological abnormalities at all concentrations and a dose-dependent effect of ATZ on DNA through the ECA. There was no difference among treatments in gills. In the SSB there was no significant difference in MNT, but the ECA showed an increase of DNA breakages at 10 μg L-1 treatment. GCA showed higher DNA damage on fish exposed to 2 and 100 μg L-1. Our results show a trend to dose-dependent genotoxic effect of ATZ, which causes damage to the DNA of Rhamdia quelen even in a concentration considered safe by regulatory agencies

Co-exposure effects of Titanium Dioxide Nanoparticles and Metals on antioxidant systems and DNA in the fish Hoplias intermedius

Metallic nanoparticles are one of the most produced and used engineered nanomaterial and their wide applications lead to environmental contamination. The aquatic environment is the major recipient of wastes containing nanoparticles and other co-occuring contaminants. We aimed to evaluate genotoxic and biochemical effects of acute exposure to nano-TiO2 in the fish Hoplias intermedius and the interaction to metals. Besides assessing the nanoparticles’ physical-chemical properties we performed an acute exposure with 0.1; 1; 10 μg g-1 nano-TiO2, alone and with lead (21 μgg-1) and aluminium (50 μgg-1). A set of biomarkers were evaluated in the liver such as genotoxicity by comet assay and biochemical biomarkers (SOD, CAT, GPx, GSH, EROD, GST). Most of the biomarkers were altered by the metals, and the nanoparticles caused decrease in SOD (0.1 and 1μg g-1), GSH (1μg g-1), and GST (0.1 μg g-1). In co-exposure, some metal effects were attenuated. There was an increase in EROD activity for most co-exposure groups. Nano-TiO2 was not genotoxic in the experimental conditions. We did not observe any increase in DNA breaks in co-exposure, although, nanoparticles changed the response of some biochemical biomarkers

Genome Size Evaluation in Tetraodontiform Fishes from the Neotropical Region

Abstract Smooth pufferfish of the family Tetraodontidae had become pure genomic models because of the remarkable compaction of their genome. This trait seems to be the result of DNA loss following its divergence from the sister family Diodontidae, which possess larger genomes. In this study, flow cytometry was used for estimate the genome size of four pufferfish species from the Neotropical region. Cytogenetic data and confocal microscopy were also used attempting to confirm relationships between DNA content and cytological parameters. The haploid genome size was 0.71±0.03 pg for Sphoeroides greeleyi, 0.34±0.01 pg for Sphoeroides spengleri, 0.82± 0.03 pg for Sphoeroides testudineus (all Tetraodontidae), and 1.00±0.03 pg for Chilomycterus spinosus (Diodontidae). These differences are not related with ploidy level, because 46 chromosomes are considered basal for both families. The value for S. spengleri represents the smallest vertebrate genome reported to date. Since erythrocyte cell and nuclear sizes are strongly correlated with genome size, the variation in this last is considered under both adaptive and evolutionary perspectives

Liver damage in two neotropical fish species from a polluted estuarine area

A multi-biomarker approach was used to evaluate the liver health of two Neotropical fish species (Cathorops spixii and Atherinella brasiliensis) that inhabit two different sites of the Paranaguá bay (Paraná – Brazil) and a reference site in the Garatuba bay. Fish were sampled during summer and winter, so the variation of the responses can reflect the actual conditions of sampling sites. Data showed that fish from both sites of the Paranaguá bay are affected by the presence of pollutants from different sources. Both fish species presented adverse biomarker responses mainly in the summer, probably due to the increased human population during the period. Chronic effects in the liver related with the contamination. Thus, the results demonstrated that pollution in Paranaguá bay induce liver damage in fish that inhabit this area

Caracterizaçăo cromossômica de espécies da família Ariidae (Teleostei, Siluriformes) pertencentes ao litoral paranaense /

Orientadora : Marta Margarete CestariCo-orientador : Roberto Ferreira ArtoniDissertaçăo (mestrado) - Universidade Federal do Paraná, Setor de Cięncias Biológicas, Programa de Pós-Graduaçăo em Genética. Defesa: Curitiba, 2008Inclui bibliografi

Two genetic stocks of steindachneridion melanodermatum living in sympatry in nature and genetic variability of wild parents and F1 generation

Steindachneridion melanodermatum is a large Brazilian catfish, highly prized for sport fishing and for its meat. Specimens of this species, both caught in nature from Iguacu River and F1 fish born in captivity, were analyzed with regard to patterns of RAPD molecular markers. Genetic similarity ranged from 0.57 to 0.95; two groups were determined for the wild specimens. The results suggest different genetic lineages in sympatry in nature. Heterozygosity and percentage of polymorphic loci were 0.31 and 79% and 0.23 and 62%, respectively, for the two populations of wild specimens and 0.26 and 66%, respectively, for those born in captivity. © FUNPEC-RP