Johnny Ferraz Dias

Genetic damage in soybean workers exposed to pesticides: Evaluation with the comet and buccal micronucleus cytome assays

Soybean cultivation is widespread in the State of Rio Grande do Sul (RS, Brazil), especially in the city of Espumoso. Soybean workers in this region are increasingly exposed to a wide combination of chemical agents present in formulations of fungicides, herbicides, and insecticides. In the present study, the comet assay in peripheral leukocytes and the buccal micronucleus (MN) cytome assay (BMCyt) in exfoliated buccal cells were used to assess the effects of exposures to pesticides in soybean farm workers from Espumoso. A total of 127 individuals, 81 exposed and 46 non-exposed controls, were evaluated. Comet assay and BMCyt (micronuclei and nuclear buds) data revealed DNA damage in soybean workers. Cell death was also observed (condensed chromatin, karyorhectic, and karyolitic cells). Inhibition of non-specific choline esterase (BchE) was not observed in the workers. The trace element contents of buccal samples were analyzed by Particle-Induced X-ray Emission (PIXE). Higher concentrations of Mg, Al, Si, P, S, and Cl were observed in cells from workers. No associations with use of personal protective equipment, gender, or mode of application of pesticides were observed. Our findings indicate the advisability of monitoring genetic toxicity in soybean farm workers exposed to pesticides.

Heavy metals and DNA damage in blood cells of insectivore bats in coal mining areas of Catarinense coal basin, Brazil

We assessed the content of heavy metals in the liver and the DNA damage in blood cells of insectivore bats in the Catarinense Carboniferous Basin, Southern Brazil. Three bats species (Molossus molossus, Tadarida brasiliensis and Eptesicus diminutus) were collected in a coal mining area and in a control area. The heavy metal content in bats was detected according to the PIXE technique and the DNA damage was assessed by the Comet assay. The contents of Cr, Ni, Cu and Pb in M. molossus and of Cu and Fe in T. brasiliensis from the coal mining area was higher than in the animals from the control area. In both areas differences in metal contents in the liver were observed between the bat species. The parameters assessed by the Comet assay were significantly higher in E. diminutus as compared to M. molossus and T. brasiliensis. Values of both Comet assay parameters were significantly higher in the mining area as compared to the control area only for T. brasiliensis.

Antioxidant supplementation attenuates oxidative stress in chronic hepatitis C patients

UNLABELLED Reactive oxygen species (ROS) overgeneration is involved in the pathogenesis of hepatitis C. The aim of this study was to evaluate the antioxidant status in the blood of HCV infected patients treated or not with standard therapy before and after supplementation of vitamins E, C and zinc. Biomarkers of oxidative stress were evaluated in the blood of three groups of patients: group 1 - controls; group 2 - HCV patients without treatment examined before and after a daily antioxidant supplementation (vitamin E 800 mg, C 500 mg and zinc 40 mg) for 6 months; and group 3 - HCV patients treated with pegylated interferon combined with ribavirin, also examined before and after the same antioxidant supplementation. Before antiviral treatment HCV patients showed enhanced superoxide dismutase, catalase and glutathione peroxidase activities and decreased glutathione reductase activity, while lipoperoxidation was increased and reduced glutathione showed decreased levels compared to controls. Treatment with standard therapy enhanced the activities of catalase and glutathione S-transferase, increased contents of protein carbonyl and promoted further reduced glutathione depletion. After antioxidant supplementation, decreased catalase and glutathione S-transferase activities, decreased lipoperoxidation in group 2, and increased reduced glutathione contents in both supplemented groups were detected. Before antioxidant supplementation, alanine aminotransferase and gamma glutamyl transferase contents showed significant increases in group 2. CONCLUSION Untreated HCV patients and also those treated with the standard therapy are coping with a systemic oxidative stress. The antioxidant supplementation conferred an antioxidant protection to both supplemented groups attenuating oxidation processes related to the disease.

Evaluation of genetic damage in open-cast coal mine workers using the buccal micronucleus cytome assay.

Coal is the largest fossil fuel source used for the generation of energy. However, coal extraction and its use constitute important pollution factors; thus, risk characterization and estimation are extremely important for the safety of coal workers and the environment. Candiota is located to the southeast of the state of Rio Grande do Sul and has the largest coal reserves in Brazil, and the largest thermal power complex in the state. In the open‐cast mines, the coal miners are constantly exposed to coal dust. The human buccal micronucleus cytome (BMCyt) assay has been used widely to investigate biomarkers for DNA damage, cell death, and basal cell frequency in buccal cells. The aim of this study was to assess whether prolonged exposure to coal dust could lead to an increase in genomic instability, cell death, and frequency of basal cells using the BMCyt assay. In the analysis of epithelial cells, the exposed group (n = 41) presented with a significantly higher frequency of basal cells, micronuclei in basal and differentiated cells, and binucleated cells compared to the non‐exposed group (n = 29). The exposed group showed a significantly lower frequency of condensed chromatin cells than the non‐exposed group. However, we found no correlation between DNA damage and metal concentration in the blood of mine workers. DNA damage observed in the mine workers may be a consequence of oxidative damage resulting from exposure to coal residue mixtures. In addition, our findings confirm that the BMCyt assay can be used to identify occupational risk. Mol. Mutagen. 2013.

The Pmr1 protein, the major yeast Ca2+-ATPase in the Golgi, regulates intracellular levels of the cadmium ion.

Cadmium is a nonessential, highly toxic heavy metal that shows ionic properties similar to calcium. These ionic similarities imply that the cadmium ion, Cd2+, is a calcium ion, Ca2+, receptor-agonist, affecting the same biochemical pathways involved in Ca2+ homeostasis. In the yeast Saccharomyces cerevisiae, the PMC1 and PMR1 genes encode vacuolar and Golgi Ca2+-ATPases, respectively. The PMR1 protein product Pmr1p is involved in both Ca2+ and Mn2+ homeostasis. This study investigated the importance of Pmc1p and Pmr1p for Cd2+ cellular detoxification. Using the standard techniques of yeast molecular research and a multielemental procedure named particle-induced X-ray emission, Pmr1p was identified as a protein that directly participates in the detoxification of Cd2+, possibly through the secretory pathway. The results allow us to posit a model of Cd2+ detoxification where Pmr1p has a central role in cell survival in a Cd2+-rich environment.

Genotoxic biomonitoring of tobacco farmers: Biomarkers of exposure, of early biological effects and of susceptibility

Tobacco farming presents several hazards to those who cultivate and harvest the plant. The genotoxic and mutagenic effects in tobacco farmers were investigated. In order to verify the relationship between genetic susceptibility and biomarkers GSTT1, GSTM1, GSTP1, CYP2A6, PON, OGG1, RAD51, XRCC1, and XRCC4 genes polymorphism were evaluated. Oxidative stress markers and trace elements content were determined. Peripheral blood cells samples were collected from 111 agricultural workers during pesticides application and leaf harvest, and 56 non-exposed subjects. Results show that farmers are exposed to mixture of substances with genotoxic and cytotoxic potential. Only GSTM1 null and CYP2A6*9 showed significant associations with cytokinesis-blocked micronuclei assay results. In pesticide application an increase in trace elements content was observed. The results indicated that exposure to pesticides and nicotine can influence antioxidant enzymes activity. Our study drives the attention once more to the need for occupational training on safe work environment for farm workers.

Influence of iron on mineral status of two rice (Oryza sativa L.) cultivars

Received: 02 April 2007; Returned for revision: 02 July 2007; Accepted: 14 August 2007Iron is an essential nutrient for plants. In aerobic conditions, Fe is highly unavailable for plant uptake, and Fe deficiencycan be severe in plants grown in calcareous soils. In waterlogged soils, however, Fe availability increases and can reachtoxic concentrations. Rice is an important staple crop worldwide and faces iron deficiency or excess, depending on thegrowth conditions. To contribute to the study of mechanisms involved in response to Fe deficiency and resistance to Feexcess, experiments were carried out with rice cultivars BR-IRGA 409 (I409, susceptible to Fe toxicity) and EPAGRI 108(E108, resistant to Fe toxicity) grown in culture solutions and submitted to Fe excess, control concentration ordeficiency (500, 6.5 or zero mg L

Genetic damage in coal miners evaluated by buccal micronucleus cytome assay

During coal mining activities, large quantities of coal dust, ashes, polycyclic aromatic hydrocarbons and metals are released into the environment. This complex mixture presents one of the most important occupational hazards for health of workers. The aim of the present study was to evaluate the genetic damage together with the presence of inorganic elements, in an exposed workers population to coal mining residues of Guajira-Colombia. Thus, 100 exposed workers and 100 non-exposed control individuals were included in this study. To determine genetic damage we assessed the micronucleus (MN) frequencies and nuclear buds in buccal mucosa samples (BMCyt) assay, which were significantly higher in the exposed group than non-exposed control group. In addition, karyorrhectic and karyolytic cells were also significantly higher in the exposed group (cell death). No significant difference was observed between the exposed groups engaged in different mining activities. No correlation between age, alcohol consumption, time of service and MN assay data were found in this study. However, the content of inorganic elements in blood samples analyzed by a Particle-induced X-ray emission technique (PIXE) showed higher values of silicon (Si) and aluminum (Al) in the exposed group. In this study we discuss the possibility of DNA damage observed in the mine workers cells be a consequence of oxidative damage.

Role of ferritin in the rice tolerance to iron overload

Plants ordinarily face iron (Fe) deficiency, since this mineral is poorly available in soils under aerobic conditions. Nonetheless, wetland and irrigated rice plants can be exposed to excess, highly toxic Fe. Ferritin is a ubiquitous Fe-storage protein, important for iron homeostasis. Increased ferritin accumulation resulting from higher Fe availability was shown in some plant species. However, the role of ferritin in tolerance mechanisms to Fe overload in rice is yet to be established. In this study, recombinant rice ferritin was expressed in Escherichia coli, producing an anti-rice ferritin polyclonal antibody which was used to evaluate ferritin accumulation in two rice (Oryza sativa L.) cultivars, either susceptible (BR-IRGA 409) or tolerant (EPAGRI 108) to Fe toxicity. Increased ferritin mRNA and protein levels resulting from excess Fe treatment were detected in both cultivars, with higher ferritin protein accumulation in EPAGRI 108 plants, which also reached lower shoot Fe concentrations when submitted to iron overload. The tolerance mechanism to excess Fe in EPAGRI 108 seems to include both restricted Fe translocation and increased ferritin accumulation. This is the first work that shows higher accumulation of the ferritin protein in an iron-excess tolerant Oryza sativa cultivar, providing evidence of a possible role of this protein in iron tolerance mechanisms.

Assessment of heavy metal content and DNA damage in Hypsiboas faber (anuran amphibian) in coal open-casting mine.

The aims of the study were to determine the heavy metal content in the tissues of Hypsiboas faber from a coal mining area and to compare the DNA damage in the blood cells of these animals with that of animals living in an unpolluted area. The heavy metal content was detected according to the technique of Particle-Induced X-ray Emission (PIXE) and the DNA damage was assessed by the Comet assay. Our results reveal that the specimens of H. faber collected from the coal mining area exhibited elements of order Fe>Cu>Al>Zn>Rb>Mn>Br, independently of the organ. The values of Comet assay parameters (DNA damage index and DNA damage frequency) were significantly higher in specimens collected from the coal mining area than in the reference animals. Our study concludes that the coal mining residues are genotoxic to amphibians and may have adverse effects on soil, water, vegetation and wild animals.