Evaluation of soils under the influence of coal mining and a thermoelectric plant in the city of Candiota and vicinity, Brazil.

Coal burning generates gases, particles, and condensation by-products that are harmful to soil, water, and to the atmosphere. The aim of this study was to characterize and identify the cytotoxic and mutagenic potential of soil samples from the cities of Aceguá, Bagé, Candiota and Pinheiro Machado, near a large coal-fired power plant. Our study describes soil characteristics and contributes to the evaluation of the genotoxic activity of coal mining and burning, using the Comet Assay and Micronucleus test in V79 cells, as well as mutagenicity assays with Salmonella typhimurium strains. Comet Assay results show that the winter soil samples of Candiota and Pinheiro Machado induced a significant increase of the Damage Index for cells, as well as for the Aceguá summer sample. The micronucleus test did not detect differences between cities and seasons. A component analysis indicates associations between results obtained in Comet Assay and Ti and phenanthene concentrations for Pinheiro Machado during the winter, and Al for Aceguá during the summer and Zn during the winter. Results of Salmonella/microsome assays were negative, only Candiota and Pinheiro Machado samples showed a statistical increase of his + colonies in TA102. Our work describes biological data on these cells exposed to coal-contaminated soil, confirming the sensitivity of the Comet Assay in V79 cells and Salmonella/microsome assay for the evaluation of the effects of complex mixtures. These findings help to understand the spatial distribution of contaminants in the local soil related to a power plant, which is important for planning public safety actions.

Genotoxic effect induced by dried nicotiana tabacum leaves from tobacco barns (kiln-houses) in chinese hamster lung fibroblast cells (V79).

Nicotiana tabacum is the most cultivated tobacco species in the state of Rio Grande do Sul, Brazil. Workers who handle the plant are exposed to the leaf components during the harvesting process and when separating and classifying the dried leaves. In addition to nicotine, after the drying process, other components may be found including tobacco-specific nitrosamines, polycyclic aromatic hydrocarbons, as well as pesticides residues. The objective of this study was to examine the genotoxicity attributed to the aqueous extract of dried tobacco leaves obtained from tobacco barns using Chinese hamster lung fibroblast cells (V79) as a model system by employing alkaline comet assay, micronucleus (MN) and Ames test. MTT assay was used to assess cytotoxicity and establish concentrations for this study. Data demonstrated cell viability > 85% for concentrations of 0.625-5 mg/ml while the comet assay indicated a significant increase in DNA damage at all concentrations tested. A significant elevation of MN and nuclear buds (NBUD) was found for 5 mg/ml compared to control and other dry tobacco leaves concentrations (0.625-2.5 mg/ml). Mutagenicity was not found using the Salmonella/Microsome test (TA98, TA100, and TA102 strains) with and without metabolic activation. The concentration of inorganic elements was determined employing the PIXE technique, and 13 inorganic elements were detected. Using CG/MS nicotine amounts present were 1.56 mg/g dry tobacco leaf powder. Due to the observed genotoxicity in V79 cells, more investigations are needed to protect the health of tobacco workers exposed daily to this complex mixture of toxic substances present in dry tobacco leaves.

Evaluation of the cytotoxic and genotoxic effects of Sida planicaulis Cav extract using human neuroblastoma cell line SH-SY5Y.

Sida planicaulis is a weed thought to have originated in Brazil, where it is present in abundant quantities, but also this plant is also found in south-central Florida, Indian Ocean Islands, and the Pacific Islands. Sida planicaulis produces neurotoxicity that adversely affects livestock breeding with heavy animal losses and consequent negative impact on Brazil's economy. The aim of this study was to determine the chemical profile, cytotoxic and genotoxic effects of ethanolic extracts of S. planicaulis collected in winter (leaf extract) and summer (leaf extract and leaf + flower extract) using an in vitro model of human neuroblastoma cell line SH-SY5Y. Phytochemical screening demonstrated the presence of alkaloids, flavonoids, and apolar compounds. Rutin, quercetin, and swainsonine were detected by HPLC and GC/MS, respectively. Phosphorus, potassium, iron, and zinc were the inorganic elements found. Extracts produced cytotoxicity at all concentrations tested (7-4,000 µg/ml) as evidenced by the colorimetric assay [3-(4,5-dimethyl-thiazol-2-yl) -2,5-diphenyl-tetrazolium bromide (MTT)]. Based upon the alkaline comet assay extracts were found to induce genotoxicity at concentrations ranging from 0.437 to 7 µg/ml. DNA damage produced by extracts was affirmed using a modified comet assay with the enzymes Endo III and FPG in a concentration dependent manner. Further, enzyme-modified comet assay showed both oxidized purines and pyrimidines, and consequently oxidative stress was related to genomic instability and cell death. Data suggest that low concentrations of ethanolic extracts of S. planicaulis (different seasons) induced increased DNA damage related to oxidative stress and chemical composition.

Cytotoxic and genotoxic evaluation of cotinine using human neuroblastoma cells (SH-SY5Y).

Cotinine is the main metabolite of nicotine, which is metabolized in the liver through a cytochrome P450 enzyme. Different studies point to genetic instability caused by nicotine, such as single and double DNA strand breaks and micronuclei formation, but little is known about the effect of cotinine. Therefore, the present in vitro study assessed the effects of cotinine on cell viability and DNA damage in SH-SY5Y neuroblastoma cells, as well as genotoxicity related to oxidative stress mechanisms. Comparisons with nicotine were also performed. An alkaline comet assay modified by repair endonucleases (FPG, OGG1, and Endo III) was used to detect oxidized nucleobases. SH-SY5Y neuronal cells were cultured under standard conditions and exposed for 3 h to different concentrations of cotinine and nicotine. Cytotoxicity was observed at higher doses of cotinine and nicotine in the MTT assay. In the trypan blue assay, cells showed viability above 80% for both compounds. Alkaline comet assay results demonstrated a significant increase in damage index and frequency for cells treated with cotinine and nicotine, presenting genotoxicity. The results of the enzyme-modified comet assay suggest a DNA oxidative damage induced by nicotine. Unlike other studies, our results demonstrated genotoxicity induced by both cotinine and nicotine. The similar effects observed for these two pyridine alkaloids may be due to the similarity of their structures.

Base excision repair (OGG1 and XRCC1) and metabolism (PON1) gene polymorphisms act on modulation of DNA damage and immune parameters in tobacco farmers.

Pesticides are one of the most frequently investigated chemical, due to their multiple uses in agricultural and public health areas. This study evaluates lymphocytes CBMN (cytokinesis-block micronucleus cytome assay), inflammatory markers, inorganic elements in blood samples, and the relationship of these parameters with XRCC1Arg194Trp, OGG1Ser326Cys and PON1Gln192Arg polymorphisms in a population of tobacco farmers. The study population comprised 129 agricultural workers exposed to pesticides and 91 nonexposed. Farmers had significantly increased NPB (nuclear plasmatic bridge), MN (micronucleus) and NBUD (nuclear bud) frequencies, as well as IL-6 (interleukin 6) and TNF-α (tumor necrosis factor alpha) serum levels, and decreased cytokines CD4+/CD8+ ratio. In the exposed group, XRCC1 Trp/- was correlated with decreased NDI (nuclear division index), and OGG1 Cys/- was associated with higher levels of NPB and decreased levels of IL-6. The combined effects of PON1 Arg/- and XRCC1 Arg/Arg were associated with increased NPB frequencies. In addition, the combination of PON1 Arg/- with XRCC1 Trp/- or OGG1 Cys/- influenced in increased levels of necrosis in farmers. Furthermore, tobacco farmers showed a positive correlation between TNF-α levels and NPB, CD4+/CD8+ ratio and NBUD; and IL-6 levels with both MN and NDI. The duration of years of work at tobacco fields was correlated positively with NBUD frequency. Sulfur, chlorine and potassium were found at increased levels in the exposed group when compared to the nonexposed one. These findings provide evidence that tobacco farmers' exposure have increased DNA damage and alter the immune system's response, and that XRCC1 and OGG1 polymorphisms could influence both biomarkers results.

DNA damage induced by coal dust, fly and bottom ash from coal combustion evaluated using the micronucleus test and comet assay in vitro.

Coal mining and combustion generating huge amounts of bottom and fly ash are major causes of environmental pollution and health hazards due to the release of polycyclic aromatic hydrocarbons (PAH) and heavy metals. The Candiota coalfield in Rio Grande do Sul, is one of the largest open-cast coal mines in Brazil. The aim of this study was to evaluate genotoxic and mutagenic effects of coal, bottom ash and fly ash samples from Candiota with the comet assay (alkaline and modified version) and micronucleus test using the lung fibroblast cell line (V79). Qualitative and quantitative analysis of PAH and inorganic elements was carried out by High Performance Liquid Chromatography (HPLC) and by Particle-Induced X-ray Emission (PIXE) techniques respectively. The samples demonstrated genotoxic and mutagenic effects. The comet assay modified using DNA-glicosilase formamidopirimidina (FPG) endonuclease showed damage related to oxidative stress mechanisms. The amount of PAHs was higher in fly ash followed by pulverized coal. The amount of inorganic elements was highest in fly ash, followed by bottom ash. It is concluded that the samples induce DNA damage by mechanisms that include oxidative stress, due to their complex composition, and that protective measures have to be taken regarding occupational and environmental hazards.