Developmental toxicity induced by Cu(OH)2 nanopesticide in zebrafish embryos.

The current study evaluates the adverse effects of Cu(OH)2 nanopesticide (CNPE) on the early life stages of zebrafish (Danio rerio). The developmental toxicity was determined using different parameters such as mortality (including LC50 ), hatching, heart rates, malformations, and alteration of the gene expressions. Zebrafish embryos (4 hpf-hours postfertilization) were exposed to 1.0, 2.0, 4.0, 8.0, and 16.0 mg/l CNPE doses until 96 hpf. The 96 hours LC50 was recorded at 6.258 mg/l. Seventy-two hpf total malformation index values for 2.0, 4.0, and 8.0 mg/l CNPE doses were 4.3, 7.2 and 7.9, respectively. 1.0 mg/l CNPE is not toxic for the zebrafish embryos/larvae. 2.0 to 8.0 CNPE doses caused some abnormalities in embryos/larvae morphology, including lack of body parts, tail deformities, chorda deformity, bubbled head, scoliosis, lordosis, weak or non-pigmentation, decreased heart rate and larva length. 16.0 mg/l CNPE caused mortality in 72 hpf. The expression levels of seven immune system-related genes (il-1ß, il-8, cebp, tlr4, hsp70, NF-kB, and mtf-1) were examined. The transcription level of il-1ß, il-8, tlr4, hsp70, and NF-kB genes significantly increased in the CNPE exposure groups. While the expression of the mtf-1 gene considerably decreased, the cebp gene expression level did not change in the 4.0 and 8.0 mg/l CNPE doses. In conclusion, CNPE could induce developmental toxicity with malformations in embryos/larvae and alter the gene expression.

Evaluation of boscalid toxicity on Daphnia magna by using antioxidant enzyme activities, the expression of genes related to antioxidant and detoxification systems, and life-history parameters.

Boscalid is a succinate dehydrogenase inhibitor fungicide commonly used to control a range of plant pathogens. Although it is one of the most common fungicides in the aquatic environment, the potential adverse effects of boscalid on freshwater invertebrates still remain unclear. This study aimed to evaluate the toxicity of boscalid on Daphnia magna (D. magna) and provide new information to assess the eco-toxicity of the boscalid on aquatic invertebrates. The effects of boscalid on malondialdehyde (MDA) level, activities of antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT) and glutathione S-transferase (GST) and the mRNA level of genes associated with antioxidant system (sod, cat, and gst) and detoxification (cytochrome P450 4 (cyp4) and nuclear respiratory factor 1 (nrf1)) were determined after 48 h treatment. The effect of boscalid on reproduction and development of D. magna was evaluated by a 21-d-chronic toxicity test. Boscalid dose-dependently altered activities of SOD, CAT, and GST and led to lipid peroxidation during acute exposure in D. magna. Exposure to 5 and 10 mg/L boscalid also significantly decreased gene expression of sod, gst, cyp4 and nrf1 but increased cat gene expression. Furthermore, chronic toxicity results showed that exposure to boscalid decreased molting frequency, number of neonates per Daphnia, and the number of broods per female as compared to the control groups. The above results indicated that boscalid had significant negative impacts on D. magna, and information present here helps to evaluate the eco-toxicity caused by boscalid on aquatic invertebrates.

Detoxification and reproductive system-related gene expression following exposure to Cu(OH)2 nanopesticide in water flea (Daphnia magna Straus 1820).

The extensive use of copper-based nanopesticides in agriculture has led to their release into the aquatic environment and causes a potential risk to aquatic biota. However, there is a lack of knowledge regarding the possible toxic effect of these nanopesticides on non-target aquatic organisms including invertebrates. Therefore, in this study, effects of commonly used copper-based nanopesticide "Kocide 3000" on gene expression related to detoxification (cyp360a8, gst, P-gp, and hr96) and reproductive system (cut, cyp314, dmrt93, and vtg) in Daphnia magna was investigated through an acute toxicity test. In general, exposure to the nanopesticide caused significant down-regulation of detoxification genes after 24 h and then significant up-regulation after 48 h. Exposure to the nanopesticide, however, significantly induced cut expression after 24 h. Moreover, dmrt93 and vtg genes were up-regulated after 48 h exposure to the nanopesticide. On the other hand, the expression of dmrt93 and vtg down-regulated at high concentration of Cu(OH)2 nanopesticide (1.5 ppm) after 96 h. The results of this study provide first evidence into the crucial role of genes related to detoxification and reproductive system in response to Cu(OH)2 nanopesticide. The use of physiological, biochemical bioassays, as well as gene expression, can help explain the toxic effect of copper-based nanopesticides and provide more insight into the exact mechanism of toxicity in non-target aquatic organisms.

Impact of copper oxide nanoparticles (CuO NPs) exposure on embryo development and expression of genes related to the innate immune system of zebrafish (Danio rerio).

CuO NPs are nanomaterials with catalytic activity and unique thermo-physical properties used in different fields such as sensors, catalysts, surfactants, batteries, antimicrobials and solar energy transformations. Because of its wide field of use, these nanoparticles accumulate in the aquatic environment and thus lead to toxic effects on aquatic organisms. The toxicological findings about CuO NPs are controversial and these effects of CuO NPs on aquatic organisms have not been elucidated in detail. Therefore, the aim of this study was to investigate the toxic effect of CuO NPs on zebrafish embryos using different parameters including molecular and morphologic. For this purpose, zebrafish embryos at 4 h after post fertilization (hpf) were exposed to different concentrations of CuO NPs (0.5, 1, 1.5 mg/L) until 96 hpf. Mortality, hatching, heartbeat, malformation rates were examined during the exposure period. In addition, Raman spectroscopy was used to determine whether CuO NPs entered into the tissues of zebrafish larvae or not. Moreover, the alterations in the expression of genes related to the antioxidant system and innate immune system were examined in the embryos exposed to CuO NPs during 96 h. The results showed that CuO NPs was not able to enter into the zebrafish embryos/larvae tissues but caused an increased the mortality rate, a delayed hatching, and a decreased heartbeat rate. Moreover, CuO NPs caused several types of abnormalities such as head and tail malformations, vertebral deformities, yolk sac edema, and pericardial edema. RT-PCR results showed that the transcription of mtf-1, hsp70, nfkb and il-1ß, tlr-4, tlr-22, trf, cebp was changed by the application of CuO NPs. In conclusion, short-term exposure to CuO NPs has toxic effects on the development of zebrafish embryos.