Flavio Manoel Rodrigues da Silva Júnior

Using the Salmonella assay to delineate the dispersion routes of mutagenic compounds from coal wastes in contaminated soil

The mutagenicity of acidic and organic extracts of surface soil under the influence of a coal-fired power plant was evaluated by Salmonella/microsome assay using strains TA97a, TA98 and TA100 in the absence and presence of exogenous metabolic systems (S9 mix). Additionally, strains YG1041 and YG1042 (sensitive to nitroderivatives) were used for the organic extracts. In general, the responses were higher in the organic extracts in the presence of S9 mix. The comparison between strains TA98 and TA100 and their derived strains YG1041 and YG1042, respectively, allowed the detection of the presence of nitro-aromatic compounds in some sampling areas, which was confirmed by chemical analysis. The interpretation of the set of mutagenesis data suggests that there are two important mutagenic compound dispersion routes in the area of study: frameshift mutagens were dispersed predominantly by runoff and leaching, while base-pair substitution mutagens were dispersed mainly by the atmosphere. This mutagenic damage might be attributed to the effects of several substances detected in the area, such as aliphatic hydrocarbons and the metals aluminum, cadmium, lead and iron.

Extraction parameters in the mutagenicity assay of soil samples.

This study aimed at investigating parameters of chemical extraction associated with the detection of mutagenicity in soil samples extracts. In order to evaluate the extraction efficiency of inorganic mutagens, besides the chemical analysis of metals, the Salmonella/microsome assay was performed in the preincubation and microsuspension procedures, using two solvents, and using two extraction methodologies. The efficiency of two organic compound extraction methods was compared by qualitative analysis using CG/MS in Scan mode. The results of the analysis of inorganic extracts correlated with the mutagenicity results. Mutagenic effects were detected only in the acidic extracts of soil that were shaken, in the microsuspension assay, both in the presence and absence of metabolic activation. The other conditions tested demonstrated higher cytotoxicity and negative mutagenic effects. As to the organic compounds, Accelerated Solvent Extraction (ASE) proved more effective than extraction using ultrasound (sonication). This study will help the implementation of extraction parameters to evaluate the presence of mutagenic substances in soil samples, both of inorganic and organic origins, suggesting the implementation of acidic extraction for the assessment of inorganic mutagenicity from soil samples and confirming the efficiency of ASE extraction for the assessment of organic compounds.

Toxicity mechanisms of onion (Allium cepa) extracts and compounds in multidrug resistant erythroleukemic cell line

Onion (Allium cepa) is being studied as a potential anticancer agent, but little is known regarding its effect in multidrug resistance (MDR) cells. In this work, the cytotoxicity of crude onion extract (OE) and fractioned extract (aqueous, methanolic and ethyl acetate), as well as some onion compounds (quercetin and propyl disulfide) were evaluated in Lucena MDR human erythroleukemic and its K562 parental cell line. The capacity of OE to induce apoptosis and/or necrosis in these cells, the possible participation of oxidative stress and DNA damage were also assessed. Similar sensitivities were obtained for both tumoral cells, however only OE caused significant effects in the cells. In K562 cells, a significant increase of apoptosis was verified while the Lucena cells experienced a significant increase of necrosis. An antioxidant capacity was verified for OE discarding oxidative damage. However, OE provoked similar significant DNA damage in both cell lines. Thus, the OE capacity to overcome the MDR phenotype suggests anti-MDR action of OE.

Biochemical responses induced by co-exposition to arsenic and titanium dioxide nanoparticles in the estuarine polychaete Laeonereis acuta.

The production and use of nanoparticles, as titanium dioxide (nanoTiO2) is growing exponentially in the last years and their release into aquatic environment seem be inevitable. Once into environment, this nanomaterial can interact with other contaminant, as arsenic, and to exert toxic effect in living organisms. So, the objective of present study was to evaluate if the co-exposure to nanoTiO2 (1mg/L) can alter the As effect (nominal concentration of 50μg/L) in the estuarine polychaeta Laeonereis acuta after 48h of exposure. Were performed biochemical analyses such ROS production, enzymatic activities (GST, GR and GSTΩ), total antioxidant capacity against peroxyl radicals and damage to macromolecules (lipid and DNA), besides also were determined the accumulation of total arsenic and arsenic speciation in the worms. The results showed that co-exposure induced an increase in the ROS levels, decrease in total antioxidant capacity, increase in GR activity, and damage in lipid and DNA. Also, the co-exposure showed to affect the metabolization capacity of arsenic characterized by increase in dimethylated arsenic forms, a compound moderately toxic. So, these results suggest that the co-exposure to both contaminants is harmful to this species and the use of nanoTiO2 to treatment of contaminated water by arsenic should be considered of a toxicological point of view.

Developmental effects of parental exposure to soil contaminated with urban metals

Soil is a highly complex material, and because of rapid population growth, intense industrial activity and petrochemical development, it has suffered from contamination with substances of various origins. These environmental contaminants may have detrimental effects on human health, particularly during development. Due to the ability to transmit contaminants to the fetus, evaluating the effects of exposure of pregnant women on the psychomotor development of their offspring is of particular interest. Therefore, this study aimed to investigate the effects of exposure of female rats to an urban soil influenced by the dispersion of air contaminants during periods of pre-pregnancy, pregnancy and lactation on offspring development. Using physiological, behavioral and hematological parameters, deleterious effects on offspring were assessed. In behavioral parameters, parental exposure during pregnancy and lactation resulted in no significant differences in the evaluated parameters when compared to the control group. In contrast, pups from the pre-pregnancy group displayed decreased locomotor and exploratory activity in addition to increased levels of anxiety. Furthermore, offspring of rats exposed to contaminated urban soil during pre-pregnancy demonstrated significant changes in weight gain and development length and a reduction in the number of platelets compared to controls. Significantly, pups born to mothers exposed to contaminated urban soil during the pregnancy displayed changes in birth weight, weight gain during the growth, development length, incisor eruption and opening of the ears in addition to a reduction in their physical performance and a change in the number of lymphocytes. These results clearly show the negative influence of parental exposure to contaminated urban soil on the general development of the rats during the periods studied. These data indicate that developing organisms are highly sensitive to external factors. Further, they demonstrate the utility of these various biomarkers for identifying and displaying toxic effects of exposure to contaminated soils.

Methylene blue toxicity in zebrafish cell line is dependent on light exposure

Methylene blue (MB) has been widely applied in the clinical area and is currently being used in aquaculture as biocide. Some recent studies have emphasized the importance of understanding the action mechanism and the MB cellular targets. In this sense, zebrafish is considered a relevant model to study the intrinsic pathway of apoptosis as well as the cellular responses involving DNA damage and repair. So, the aim of the present study was to compare MB action mechanisms in a zebrafish cell line, both in the absence (MB alone; dark toxicity) and in the presence of photosynthetically active radiation (MB+PAR; phototoxicity). There was a significant increase of the levels of reactive oxygen and nitrogen species 3 h after MB treatment, whereas this increase was only observed 12 h after treatment with MB+PAR. All treatments with MB resulted in an increase in DNA damage after 3 and 6 h. However, cell death by apoptosis was observed from 6 h after treatment with MB+PAR and 12 h after treatment with MB alone. The expression of genes related to apoptosis was altered after MB and MB+PAR treatment. Therefore, this zebrafish cell line is sensitive to the photodynamic action of MB; MB is able to generate DNA damage and induce apoptosis in this cell line both alone and in the presence of PAR. However, the pathways leading to apoptosis in this model appear to be dependent on the type of MB exposure (in the presence or absence of PAR).

Biomonitoring of trace elements in urine samples of children from a coal-mining region

Biomonitoring through urine samples is important for evaluating environmental exposure, since urine is the main form of excretion for most chemical elements. Children are considered more vulnerable to adverse environmental conditions, especially children in developing countries. This study aimed to biomonitor trace elements in urine samples in children from a coal-mining region in the extreme south of Brazil. A cross-sectional study was conducted on 96 children between 6 and 11 years of age. Socioeconomic data and urine samples were collected to estimate the concentration of iron, zinc, selenium, lead, and cadmium. The prevalence of metals above the reference values was 52.0% for Se, followed by 15.6% for Zn. The data point toward a vulnerability to adverse environmental conditions in these children. Although the concentrations of the elements did not reveal intoxication cases, biomonitoring should be carried out continuously in order to assess exposure to metals and ensure the health of the population. This article provides data that help determine natural levels of metallic elements in children, specifically in South America, which have not yet been established.

Filamentous fungi isolated from Brazilian semiarid tolerant to metallurgical industry wastes: an ex situ evaluation

The purpose of this study was to assess the impact of metallurgical industry wastes on the semiarid soil microbiota using physico-chemical and microbiological parameters, highlighting the filamentous fungi assembly. Soil samples were collected in an area of industrial waste deposit contaminated with lead and mixed with natural soil (control soil) in seven different concentrations (0, 7.5, 15, 30, 45, 60 and 100%). The results showed alterations on the physico-chemical properties of the soil treated with industrial wastes, with a gradate increase of the soils pH (5.6-10.4) and electrical conductivity (0.3-14.7 dS m-1) and also reduction of organic matter (7.0-1.8%). The use of microbiological parameters (fungal richness and diversity, CO2emission, and the carbon on the microbial biomass) enabled the identification of alterations on the microbial community due to stress caused by the exposure to industrial wastes, despite the presence of Thielavia, Chaetomium and Aspergillus tolerant to high concentrations of the scoria. Therefore, these filamentous fungi could be used in biomonitoring and bioremediation studies in the soils contaminated by industrial wastes.

Geno- and cyto-toxicity in free-living rodent Mus spretus exposed to simulated onshore oil spill.

AbstractThis study investigated geno- and cyto-toxic damage in the free-living rodent, Mus spretus after exposure to a simulated spill of crude oil on soil. The results revealed increased mutagenicity and cytotoxicity in bone marrow cells and increased DNA damage in blood cells. Exposure to crude oil increased sperm abnormalities, with lasso-like folds being the most common. These results point to the value of this rodent in serving as a sentinel species for the monitoring and prediction of environmental hazards.

Estresse oxidativo induzido por petróleo no ratinho-das-dunas: Calomys laucha (Rodentia, Cricetidae)

Calomys laucha e um pequeno roedor encontrado na America do Sul, em pastagens, areas agricolas, margem de estradas e campos de cultivo de cereais. No Brasil, a area de ocorrencia do animal esta concentrada em dunas costeiras do litoral gaucho, onde se alimenta e constroi ninhos para reproducao, estando suscetivel aos efeitos de atividades antropicas na regiao costeira e marinha. O presente estudo teve por objetivo utilizar biomarcadores de dano oxidativo para investigar os efeitos do derrame simulado de petroleo em C. laucha. Os animais (n= 6 por tratamento) foram expostos a cinco diferentes concentracoes de petroleo em substrato artificial: 0, 1, 2, 4 e 8 % (v/v). Aproximadamente 1 kg de substrato foi colocado no fundo das gaiolas e os animais machos foram expostos durante 14 dias, com acesso livre a agua e racao comercial para roedores. Apos esse periodo, foram recolhidos testiculos, figado e celulas sanguineas (linfocitos) para investigacao de dano oxidativo em lipidios e proteinas e da capacidade antioxidante contra radical peroxil (ACAP). Os animais expostos ao petroleo demonstraram aumento da peroxidacao lipidica nos tres homogeneizados analisados, mas as respostas de carbonilacao de proteinas e a ACAP foram tecido-dependentes. Estes padroes de resposta distintos sugerem diferencas na distribuicao do contaminante no organismo e/ou na capacidade do tecido-alvo em responder a presenca dos agentes toxicos e podem ser uteis para a compreensao dos mecanismos de toxicidade do petroleo em mamiferos silvestres. Por fim, o C. laucha demonstra ser um bom modelo biologico para prever impactos na interface zona costeira/ambiente marinho.