RESUMEN
Neonicotinoids and phenylpyrazoles are classes of neurotoxic insecticides which are able to bind at different ligand sites of neural receptors, leading to the deregulation of insect neural activity and hence resulting in death. The misuse or indiscriminate use of these chemicals is directly associated with several toxicological effects in biota and at different trophic levels. Based on this premise, the aim of the present study was to evaluate and compare the genotoxic capacity of different concentrations of thiamethoxam (TMX), acetamiprid (ACP), imidacloprid (IMI) and fipronil (FP) through the Micronucleus Test in Tradescantia pallida (Trad-MCN). After acclimatization (24â¯h), T. pallida stems were treated with stablished concentrations of TMX, ACP, IMI and FP for 8â¯h. Then, the stems of the model organism were submitted to a recovery phase (24â¯h). The young inflorescences were harvested and fixed in Carnoy solution and, after 24â¯h, were conserved in ethanol 70% until the analyzes. The obtained anthers were macerated on slides for microscopy, stained with acetic carmine dye and covered with coverslips before analysis by light microscopy. Considering the insecticides, the micronuclei (MN) frequency in plants treated at concentrations of 0.2 and 0.4â¯gâ¯L-1 for TMX, 0.2; 0.4 and 0.8â¯gâ¯L-1 for ACP, 0.1; 0.2; 0.4; 0.8 and 1.6â¯gâ¯L-1 for IMI and 0.2; 0.4; 0.8 and 1.6â¯gâ¯L-1 for FP differed statistically (pâ¯<â¯0.05, Tukey) from the MN frequency of the negative control. All chemicals evaluated revealed genotoxic activity in T. pallida at the highest concentrations.
Asunto(s)
Insecticidas/toxicidad , Pruebas de Micronúcleos , Tradescantia/efectos de los fármacos , Relación Dosis-Respuesta a Droga , Pruebas de Mutagenicidad , Neonicotinoides/toxicidad , Nitrocompuestos/toxicidad , PirazolesRESUMEN
Spinosad (SPN) is a naturally-occurring insecticide obtained from the fermentation process of the actinomycete Saccharopolyspora spinosa. Owing to the larvicidal action, the compound has been used in the control of Aedes aegypti. As a new insecticide commercially available in the market, few data are reported on genotoxic effects in non-target organisms. The objective of the present study was to evaluate the mutagenic effect of SPN through the Micronucleus Test in Tradescantia pallida (Trad-MCN) and using the mutation and somatic recombination test in Drosophila melanogaster (SMART). At the Trad-MCN, after acclimatization (24â¯h), T. pallida stems were submitted to chronic treatment with SPN at concentrations of 0.156; 0.312; 0.625; 1.25 and 2.5â¯g/L solution for 24â¯h, followed by a recovery period. In SMART, considering the third stage larvae, offspring resulting from the ST and HB crossing were placed on chronic treatment (48â¯h) with 0.039; 0.078 and 0.156⯵g/mL of SPN solution. No mutagenic effect was observed at any of the evaluated concentrations in SMART. Additionally, SPN is more toxic after metabolism via CYP6A2 (cytochrome P450) in D. melanogaster. However, SPN at the concentrations of 0.625; 1.25 and 2.5â¯g/L was able to induce high frequency of micronuclei in T. pallida. Under the experimental conditions of T. pallida in the present study, SPN caused genotoxic activity.
Asunto(s)
Drosophila melanogaster/efectos de los fármacos , Macrólidos/toxicidad , Pruebas de Mutagenicidad/métodos , Tradescantia/efectos de los fármacos , Animales , Proteínas de Drosophila , Drosophila melanogaster/genética , Combinación de Medicamentos , Femenino , Insecticidas/toxicidad , Larva/efectos de los fármacos , Masculino , Pruebas de Micronúcleos , Mutágenos/toxicidad , Tradescantia/genéticaRESUMEN
Melipona scutellaris Latreille, 1811 (Hymenoptera, Apidae) is a pollinator of various native and cultivated plants. Because of the expansion of agriculture and the need to ensure pest control, the use of insecticides such as fipronil (FP) has increased. This study aimed to evaluate the effects of sublethal doses of FP insecticide on M. scutellaris at different time intervals (6, 12, and 24â¯h) after exposure, via individually analyzed behavioral biomarkers (locomotor activity, behavioral change) as well as the effect of FP on different brain structures of bees (mushroom bodies, antennal cells, and optic cells), using sub-individual cell biomarkers (heterochromatin dispersion, total nuclear and heterochromatic volume). Forager bees were collected when they were returning to the nest and were exposed to three different concentrations of FP (0.40, 0.040, and 0.0040â¯ng a.i/bee) by topical application. The results revealed a reduction in the mean velocity, lethargy, motor difficulty, paralysis, and hyperexcitation in all groups of bees treated with FP. A modification of the heterochromatic dispersion pattern and changes in the total volume of the nucleus and heterochromatin were also observed in the mushroom bodies (6, 12, and 24â¯h of exposure) and antennal lobes (6 and 12â¯h) of bees exposed to 0.0040â¯ng a.i/bee (LD50/100). FP is toxic to M. scutellaris and impairs the essential functions required for the foraging activity.
Asunto(s)
Ecotoxicología/métodos , Insecticidas/efectos adversos , Animales , Abejas , BrasilRESUMEN
Physico-chemical and toxicological analyses are of fundamental importance to determine water quality. The objectives of the present study were to evaluate the toxicity, mutagenicity and carcinogenicity of samples from the Mumbuca Stream and the Perdizes River, through both SMART and the wts test, respectively, in somatic cells of Drosophila melanogaster and to quantify the amount of heavy metals and other pollutants, which are indicative of environmental quality. Water samples were collected (M1, M2, P1, P2 and MP) and submitted to physico-chemical analysis, calculating the water quality index for each sampling site. In order to evaluate the toxicity, mutagenicity and carcinogenicity of the samples, third instar larvae descended from the crossing between virgin female wts/TM3, sb1 and mwh/mwh males (wts test) and ST and HB (SMART) crosses were treated with samples from P1, P2, M1, M2 and MP sites. The physico-chemical analysis and the biological assay allowed us to conclude that undetected values for heavy metals and the low frequency of mutant spots (SMART) and epithelial tumor (wts) in treated flies from the Mumbuca Stream and Perdizes River may be due to the reduction of ceramic activities in the municipality. The physico-chemical analyzes identified altered the environmental quality parameters, which directly influenced the survival of D. melanogaster treated with samples of M2 and MP, which according to the WQI were classified as regular and poor environmental quality, respectively. The altered parameters may be due to clandestine domestic sewage sent downstream of the effluent.
Asunto(s)
Monitoreo del Ambiente/métodos , Mutágenos/toxicidad , Ríos/química , Aguas del Alcantarillado/análisis , Calidad del Agua , Animales , Drosophila melanogaster/citología , Drosophila melanogaster/efectos de los fármacos , Femenino , Larva/efectos de los fármacos , Masculino , Metales Pesados/análisisRESUMEN
The continued widespread use of larvicides in Aedes aegypti control programs is still a necessary strategy, since there are no apparent efficient vaccines against arboviruses. However, chemical approaches may affect nontarget organisms and produce detrimental effects to environmental health. Therefore, the aim of this study was to conduct toxicity testing for pyriproxyfen at different concentrations using Daphnia magna and Artemia salina as model organisms to evaluate the ecotoxicological parameters. This study describes the toxicological effects of pyriproxyfen on both microcrustaceans, which are widely used in bioassays because of their sensitivity to changes in hydrosphere. Data demonstrated that the calculated EC50-48h value of pyriproxyfen was 2.5 µg/for D. magna and A. salina; the no-observed-effect concentration (NOEC) and the lowest-observed-effect concentration (LOEC) of pyriproxyfen were found to be 0.63 and 1.25 µg/L for Artemia salina and Daphnia magna, respectively. In chronic toxicity and reproduction tests on D. magna, a calculated CL50-7day (lethality on 50% of daphnids after 7 days of chronic test) and an EC50-21day (50% reduction in the reproductive output of parental daphnids after 21 days of exposure) higher than 1.25 µg/L pyriproxyfen were observed. The time of first reproduction was significantly increased in D. magna after exposure to environmentally relevant concentrations of pyriproxyfen, but other reproduction parameters were not markedly altered. Environmental risk assessment revealed that pyriproxyfen is highly toxic for both branchiopods. Data demonstrated that pyriproxyfen may produce adverse effects on the aquatic ecosystem at concentrations required to control Ae. aegypti.