Mutagenic potency in Salmonella typhimurium of organic extracts of soil samples originating from urban, suburban, agricultural, forest and natural areas.
ABSTRACT The purpose of the present work was to assess the mutagenic potency of soil samples presumably not contaminated by industrial wastes and discharges. A set of 51 soil samples was collected from areas considered as not contaminated by a known industrial activity: 11 urban samples (collected in cities), 15 suburban samples (collected in villages), 7 agricultural samples, and 18 forest or natural samples. Each soil sample was collected at the surface (0-5cm deep), dried, sieved (2mm), homogenized before organic extraction (dichloromethane/acetone 1/1 (v/v), 37 degrees C, 4h, soil/solvent ratio 1/2, m/v), solvent exchange to DMSO and sterilizing filtration. The micro-method adaptation of the standard bacterial mutagenicity test on Salmonella typhimurium strain TA98 was performed with and without a metabolic activation system (rat-liver homogenate S9), and thus detected the effect of pro-mutagens and direct mutagens, respectively. The use of a pre-incubation method increased the sensitivity of the assay. The results obtained showed a wide range of effect levels, from no effect to clear mutagenicity. In particular, the extract of all 11 urban soil samples demonstrated mutagenic activity, while the extracts of 10 of the 15 suburban samples showed mutagenicity. On the other hand, the extract of only one of the 7 agricultural samples studied induced mutations, and none of the 18 natural or forest-soil samples investigated produced mutagenic extracts. These findings seem to indicate the crucial influence of the diffuse pollution originating from different human activities on the mutagenic potency of urban soil samples. These findings make it possible to classify the soils according to their mutagenic potency. No clear correlation was found between the mutagenicity detected in soil extracts and the measured polycyclic aromatic hydrocarbon (PAH) content of the soils investigated.
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ABSTRACT: Deoxynivalenol (DON) is the major mycotoxin detected in cereal foods and a risk for human health following DON ingestion could not be excluded due to high level exposure. In this light, the hazard of DON must be carefully evaluated. Therefore, the aim of this study is to perform in vitro genotoxicity tests with DON using the Salmonella typhimurium reverse mutation assay (Ames'test), the comet assay and the micronucleus test in accordance with the OECD test guideline 487 in two human cell lines: the lymphoblastoid TK6 and the hepatoma HepaRG cells. DON gave negative results in the Ames'test performed, both with and without rat liver S9 on three strains TA98, TA100 and TA102. DON elicited cytotoxicity in TK6 and HepaRG cells but did not induce primary DNA damage. DON failed also to induce MN formation in TK6 cells with or without human and rat liver S9. After 24h of treatment, DON induced micronucleus formation in TK6 cells but only at concentrations producing more than 55±5% cytotoxicity. In HepaRG cells, DON highly increased the caspase-3/7 activity but no micronucleus induction was observed. Taken together, our results suggest that DON could be considered as a non in vitro genotoxin.Food and chemical toxicology: an international journal published for the British Industrial Biological Research Association 01/2014; 66. DOI:10.1016/j.fct.2014.01.029 · 2.61 Impact Factor
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ABSTRACT: 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.Science of The Total Environment 10/2009; 407(23):6017-23. DOI:10.1016/j.scitotenv.2009.08.021 · 4.10 Impact Factor
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ABSTRACT: The residual levels and mutagenic potency of OCPs were studied in surface sediments collected from Taihu Lake, China. The concentrations of OCPs detected in surface sediments revealed a wide range of fluctuation from 4.22 to 461ng/g dry weight (dw). Among the individual components of OCPs, much higher coefficients of variance (0.38-1.57) for each compound were detected, indicating significant difference of OCP residues among different areas over the lake. Mutagenicity of the crude extractable organic matter (EOM) from surface sediments in six typical regions was performed with Salmonella/microsome tests (Salmonella strains TA98 and TA100 with/without metabolic activation S9 mix). TA98 was more sensitive and the main mutagens detected were frameshift toxicants. Sediments collected from the north-west showed higher potency to induce mutagenicity than other regions. Poor correlation between OCP concentrations and mutagenicity suggested OCPs were not responsible for the detected mutagenic effects in sediments. Combining chemical analysis with bioassays will be a novel and useful tool for finding out the responsible environmental mutagens.Mutation Research/Fundamental and Molecular Mechanisms of Mutagenesis 02/2010; 696(1):62-8. DOI:10.1016/j.mrgentox.2009.12.013 · 4.44 Impact Factor