Toxic effects of aminophenols on aquatic life using the zebrafish embryo test and the comet assay

Gene expression profiles related to apoptosis and levels of DNA oxidative damage in primary dermal fibroblast cells (ATCC® PCS-201-012TM) treated with zirconium oxide nanoparticles

Nanoparticles have attracted growing interest in recent years. They are small and can easily penetrate into cells. We investigated the genotoxic, cytotoxic, and apoptotic effects of zirconium nanoparticles on dermal fibroblast cells, the comet assay, Xcelligence system, and apoptotic gene expression, respectively. The comet assay analysis showed a non-signifcant increase in the genetic damage index and the percentage of damaged cells in the groups exposed to 10 and 20-nm zirconium oxide nanoparticles. Xcelligence system analysis observed a decrease in the indices of cells exposed to 10 and 20 nm zirconium oxide nanoparticles in the 48th-hour, 72nd-hour, and 96th-hour data. It was observed that caspase 3 and caspase 8 gene expression levels were suppressed in cells exposed to 10 and 20 nm zirconium oxide nanoparticles. Compared to the negative control group, this suppression was significant in the 10 nm groups (p < 0.01) while it was not significant in the 20 nm groups. Although zirconium oxide nanoparticles do not show toxicity and genotoxicity at a given concentration, but the overall mechanism is still not clear regarding the consequences of these nanoparticles use and its efect on living system. However, our apoptotic gene expression studies concluded that the nanoparticle size, particularly 10 nm, had an impact on gene expression.

DNA-damage and cell cycle arrest initiated anti-cancer potency of super tiny carbon dots on MCF7 cell line

While carbon-based materials have spearheaded numerous breakthroughs in biomedicine, they also have procreated many logical concerns on their overall toxicity. Carbon dots (CDs) as a respectively new member have been extensively explored in nucleus directed delivery and bioimaging due to their intrinsic fluorescence properties coupled with their small size and surface properties. Although various in vitro/in vivo studies have shown that CDs are mostly biocompatible, sufficient information is lacking regarding genotoxicity of them and underlying mechanisms. This study aims to analyze the real-time cytotoxicity of super tiny CDs (2.05 ± 0.22 nm) on human breast cancer cells (MCF7) and human primary dermal fibroblast cell cultures (HDFa) by xCELLigence analysis system for further evaluating their genotoxicity and clastogenicity to evaluate the anti-tumor potential of CDs on breast adenocarcinoma. As combined with flow cytometry studies, comet assay and cytokinesis-block micronucleus assay suggest that the CDs can penetrate to the cell nuclei, interact with the genetic material, and explode DNA damage and G0/G1 phase arrest in cancer cells even at very low concentrations (0.025 ppm) which provide a strong foundation for the design of potentially promising CD-based functional nanomaterials for DNA-damage induced treatment in cancer therapy.

Selected Pharmaceuticals in Different Aquatic Compartments: Part II-Toxicity and Environmental Risk Assessment

Potential risks associated with releases of human pharmaceuticals into the environment have become an increasingly important issue in environmental health. This concern has been driven by the widespread detection of pharmaceuticals in all aquatic compartments. Therefore, 22 pharmaceuticals, 6 metabolites and transformation products, belonging to 7 therapeutic groups, were selected to perform a review on their toxicity and environmental risk assessment (ERA) in different aquatic compartments, important issues to tackle the water framework directive (WFD). The toxicity data collected reported, with the exception of anxiolytics, at least one toxicity value for concentrations below 1 µg L⁻¹. The results obtained for the ERA revealed risk quotients (RQs) higher than 1 in all the aquatic bodies and for the three trophic levels, algae, invertebrates and fish, posing ecotoxicological pressure in all of these compartments. The therapeutic groups with higher RQs were hormones, antiepileptics, anti-inflammatories and antibiotics. Unsurprisingly, RQs values were highest in wastewaters, however, less contaminated water bodies such as groundwaters still presented maximum values up to 91,150 regarding 17α-ethinylestradiol in fish. Overall, these results present an important input for setting prioritizing measures and sustainable strategies, minimizing their impact in the aquatic environment.

Technical Updates to the Comet Assay In Vivo for Assessing DNA Damage in Zebrafish Embryos from Fresh and Frozen Cell Suspensions

The Single-Cell Gel Electrophoresis, simply known as the Comet assay, is a sensitive and quick technique used to quantitate DNA damage, widely used to assess the effects of genotoxicants and mutagens in animal cells. Still, performing the assay on peripheral or cultured cells is far more expeditious and cost effective than solid tissue, especially from small biological model like the zebrafish embryo. The current work describes and validates a highly cost-effective protocol of the updated Comet assay designed for zebrafish embryos. Compared with the few previous applications of the Comet assay on this biological model, the present method successfully simplifies the process of cell harvesting and resuspending, producing a much higher yield of viable nucleoids with reduced basal DNA damage, even from a small number of embryos, and compatible with scoring with safe fluorescent dyes. Additionally, the protocol can be just as easily performed on freshly harvested cells of cells frozen in dimethyl sulfoxide (DMSO)-containing physiological buffer, without a significant increase of DNA damage, which is another highly relevant update, especially for researchers handling high numbers of samples.

Genotoxic action of Luna Experience-SC 400 fungicide on rat bone marrow

Background: Fungicides describe all chemicals used to control fungi that infect plants. Luna Experience SC-400 is a new line of fungicide that consist of Fluopyram and Tebuconazole. Objective: In this study, We investigated the genotoxicty and cytotoxicty of Luna Experience-SC 400 using comet assay, micronucleus test and polychromatic erythrocytes number in rat bone marrow. The present study is the first report indicating the effects of genotoxic and cytotoxic of Luna experience SC-400 on rat bone marrow cells. Material and Methods: We used three different doses (5mg/kg, 10mg/kg, 20mg/kg) of Luna Experience SC 400 at 48 h intervals during 30 days by gavage in rats.Genotoxicity was evaluated using comet assay and micronucleus test and cytotoxicity was measured the PCE/NCE rate in rat bone marrow. Results: Based on these experimental results, we report that Luna Experience-SC 400 fungicide presents genotoxic and cytotoxic potential on rat bone marrow. There is a significant difference between negative control group and all the doses of Luna Experience-SC 400 (p < 0.05) for comet assay and micronucleus. Even moderate and high doses of fungicides seem to have reached the values of almost positive control group for Genetic Damage Index (GDI) and Damaged Cell Percentage (DCP). In this study, we also investigated the PCE/NCE rate. Fungicide caused a decrease in the level of significant in the PCE/NCE ratio (p < 0.05). Conclusion: Our in vivo study suggests that the gavage exposure to Luna experience SC 400 used in the present investigation may be genotoxic and cytotoxic in rat bone marrow in view of these findings. Because this findings is first report represented in the pesticide biology, it is important to carry out more investigations using various cytogenetic tests under different experimental conditions to definitively resolve the the possible genotoxic and cytotoxic risk associated with new generation pesticides-fungicides.

Degradation Characteristics of Aniline with Ozonation and Subsequent Treatment Analysis

Owing to the toxicity and low biodegradability of aniline in water, its removal usually needs high cost processes such as adsorption and advanced oxidation. The degradation characteristics of aniline during ozonation were studied. The influence of operation parameters such as contact time, initial concentration, ozone dosage, temperature, and pH was also investigated. With ozone dosage of 22 mg/L, neutral pH, and room temperature, the ozonation removed aniline efficiently. After two hours’ ozonation, aniline removal reached 93.57%, and the corresponding COD removal was 31.03%, which indicated most of aniline was transformed into intermediates. At alkaline conditions, the aniline was more susceptible to being removed by ozonation owing to more hydroxyl radicals’ production. The results of GC-MS indicated many intermediates appeared during the process of ozonation such as butane diacid, oxalic acid, and formic acid. The intermediates produced during ozonation were more biodegradable than aniline; thus the ozonation of such organic compounds as aniline could be integrated with biological processes for further removal.

SiO2 Nanoparticule-induced size-dependent genotoxicity - an in vitro study using sister chromatid exchange, micronucleus and comet assay

Fine particles with a characteristic size smaller than 100 nm (i.e. nanoparticlesspread out in nowadays life. Silicon or Si, is one of the most abundant chemical elements found on the Earth. Its oxide forms, such as silicate (SiO4) and silicon dioxide, also known as silica (SiO2), are the main constituents of sand and quartz contributing to 90% of the Earth's crust. In this work, three genotoxicity systems "sister chromatid exchange, cytokinesis block micronucleus test and single cell gel electrophoresis (comet) assay" were employed to provide further insight into the cytotoxic and mutagenic/genotoxic potential of SiO2 nanoparticules (particle size 6 nm, 20 nm, 50 nm) in cultured peripheral blood lymphocytes as in vitro. It was observed that there is a significant decrease in Mitotic index (MI), Cytokinesis block proliferation index (CBPI), proliferation index (PRI) values expressed as Cell Kinetic parameters compared with negative control (p < 0.05). There is a statistically significant difference between negative control culture and culture exposed to SiO2 (6 nm, 20 nm, 50 nm) (p < 0.01, p < 0.01, p < 0.05, respectively). It is found that SiO2 nanoparticles at different size (6, 20, 50 nm) progressively increased the SCE frequency and DNA damage on the basis the AU values compared with negative control (p < 0.05). Results showed that the genotoxic/mutagenic and cytotoxic effects of SiO2 nanoparticules is dependent to particule size.

The protective role of curcumin on perfluorooctane sulfonate-induced genotoxicity: single cell gel electrophoresis and micronucleus test

Perfluorooctane sulfonate (PFOS) is a man-made fluorosurfactant and global pollutant. PFOS a persistent and bioaccumulative compound, is widely distributed in humans and wildlife. Therefore, it was added to Annex B of the Stockholm Convention on Persistent Organic Pollutants in May 2009. Curcumin is a natural polyphenolic compound abundant in the rhizome of the perennial herb turmeric. It is commonly used as a dietary spice and coloring agent in cooking and anecdotally as an herb in traditional Asian medicine. In this study, male rats were treated with three different PFOS doses (0.6, 1.25 and 2.5 mg/kg) and one dose of curcumin, from Curcuma longa (80 mg/kg) and combined three doses of PFOS with 80 mg/kg dose of curcumin by gavage for 30 days at 48 h intervals. Here, we evaluated the DNA damage via single cell gel electrophoresis or comet assay and micronucleus test in bone marrow in vivo. PFOS induced micronucleus frequency and decreased the ratio of polychromatic erythrocyte to normochromatic erythrocyte in bone marrow. Using the alkaline comet assay, we showed that all doses of the PFOS strongly induced DNA damage in rat bone marrow and curcumin prevented the formation of DNA damage induced by PFOS.

DNA damage and effects on glutathione-S-transferase activity induced by atrazine exposure in zebrafish (Danio rerio)

This study was undertaken to investigate the protective effect of atrazine (2-chloro-4-(ethylamino)-6-(isopropylamino)-S-triazine) on the activity of glutathione-S-transferase (GST) and DNA damage in males and females of adult zebrafish (Danio rerio). Zebrafish were exposed to control and three treatments (0.01, 0.1, and 1 mg/L) of atrazine for 5, 10, 15, 20, and 25 days. The results indicated that, for males, the GST activity at lower atrazine concentrations (0.01 and 0.1 mg/L) was markedly higher than that of the controls throughout the duration of the experiment while there was a significant inhibition of the GST activity at 1 mg/L atrazine at days 5 and 20. For females, a significant increase was detected at 0.1 mg/L on the days 5 and 15 and at 0.01 mg/L on day 20. The DNA damage in zebrafish was evaluated using the comet assay; the olive tail moments obtained for hepatopancreas were enhanced after treatment with different concentrations of atrazine on days 5, 10, 15, 20, and 25. The DNA damage increased with increasing atrazine concentrations, indicating that genotoxicity of atrazine and significant differences was found compared to the controls. In conclusion, these findings provide further evidence of the effects of atrazine on aquatic ecosystems.

Genotoxicity evaluation of drinking water sources in human peripheral blood lymphocytes using the comet assay

The potential harm of organic pollutants in drinking water to human health is widely focused on in the world; more and more pollutants with genotoxic substances are released into the aquatic environment. Water source samples were collected from 7 different localities of Nanjing City. The potential genotoxicity of organic extracts from drinking water sources were investigated by means of the comet assay in human peripheral lymphocytes. The results showed that all the organic extracts from all the water source samples could induce DNA damages of human peripheral blood lymphocytes at different levels. A significant difference (P < 0.01) was observed when compared with the solvent control. The DNA damage increased with the increase of the dosage of the original water source. Significant differences of DNA damage were observed in different drinking water sources, as shown by the multiple comparisons analysis at the dosage of 100x; the degree of DNA damage treated by Hushu waterworks (at town level) was the most serious, the arbitrary units (AU) was 141.62 +/- 6.96, however, that of Shangyuanmen waterworks (at city level) was only 109.64 +/- 2.97. The analysis also revealed that the genotoxicity of town's water sources was higher than that of the city. The results demonstrated that the comet assay can be successfully applied to the genotoxicity monitoring programs of drinking water sources.