The JaCVAM international validation study on the in vivo comet assay: Selection of test chemicals.

PubMed

Morita, Takeshi; Uno, Yoshifumi; Honma, Masamitsu; Kojima, Hajime; Hayashi, Makoto; Tice, Raymond R; Corvi, Raffaella; Schechtman, Leonard

2015-07-01

The Japanese Center for the Validation of Alternative Methods (JaCVAM) sponsored an international prevalidation and validation study of the in vivo rat alkaline pH comet assay. The main objective of the study was to assess the sensitivity and specificity of the assay for correctly identifying genotoxic carcinogens, as compared with the traditional rat liver unscheduled DNA synthesis assay. Based on existing carcinogenicity and genotoxicity data and chemical class information, 90 chemicals were identified as primary candidates for use in the validation study. From these 90 chemicals, 46 secondary candidates and then 40 final chemicals were selected based on a sufficiency of carcinogenic and genotoxic data, differences in chemical class or genotoxic or carcinogenic mode of action (MOA), availability, price, and ease of handling. These 40 chemicals included 19 genotoxic carcinogens, 6 genotoxic non-carcinogens, 7 non-genotoxic carcinogens and 8 non-genotoxic non-carcinogens. "Genotoxicity" was defined as positive in the Ames mutagenicity test or in one of the standard in vivo genotoxicity tests (primarily the erythrocyte micronucleus assay). These chemicals covered various chemicals classes, MOAs, and genotoxicity profiles and were considered to be suitable for the purpose of the validation study. General principles of chemical selection for validation studies are discussed. Copyright © 2015 Elsevier B.V. All rights reserved.

Critical issues with the in vivo comet assay: A report of the comet assay working group in the 6th International Workshop on Genotoxicity Testing (IWGT).

PubMed

Speit, Günter; Kojima, Hajime; Burlinson, Brian; Collins, Andrew R; Kasper, Peter; Plappert-Helbig, Ulla; Uno, Yoshifumi; Vasquez, Marie; Beevers, Carol; De Boeck, Marlies; Escobar, Patricia A; Kitamoto, Sachiko; Pant, Kamala; Pfuhler, Stefan; Tanaka, Jin; Levy, Dan D

2015-05-01

As a part of the 6th IWGT, an expert working group on the comet assay evaluated critical topics related to the use of the in vivo comet assay in regulatory genotoxicity testing. The areas covered were: identification of the domain of applicability and regulatory acceptance, identification of critical parameters of the protocol and attempts to standardize the assay, experience with combination and integration with other in vivo studies, demonstration of laboratory proficiency, sensitivity and power of the protocol used, use of different tissues, freezing of samples, and choice of appropriate measures of cytotoxicity. The standard protocol detects various types of DNA lesions but it does not detect all types of DNA damage. Modifications of the standard protocol may be used to detect additional types of specific DNA damage (e.g., cross-links, bulky adducts, oxidized bases). In addition, the working group identified critical parameters that should be carefully controlled and described in detail in every published study protocol. In vivo comet assay results are more reliable if they were obtained in laboratories that have demonstrated proficiency. This includes demonstration of adequate response to vehicle controls and an adequate response to a positive control for each tissue being examined. There was a general agreement that freezing of samples is an option but more data are needed in order to establish generally accepted protocols. With regard to tissue toxicity, the working group concluded that cytotoxicity could be a confounder of comet results. It is recommended to look at multiple parameters such as histopathological observations, organ-specific clinical chemistry as well as indicators of tissue inflammation to decide whether compound-specific toxicity might influence the result. The expert working group concluded that the alkaline in vivo comet assay is a mature test for the evaluation of genotoxicity and can be recommended to regulatory agencies for use. Copyright © 2014 Elsevier B.V. All rights reserved.

Revision of OECD Guidelines for Genotoxicity Testing: Current Status and Next Steps

EPA Science Inventory

Over the past 30 years, assays have been developed to evaluate chemical genotoxicity. OECD Genotoxicity Test Guidelines (TG) describe assay procedures for regulatory safety testing. Since the last OECD TG revision (1997), there has been tremendous scientific and technological pro...

Identification of early target genes of aflatoxin B1 in human hepatocytes, inter-individual variability and comparison with other genotoxic compounds

DOE Office of Scientific and Technical Information (OSTI.GOV)

Josse, Rozenn; Dumont, Julie; Fautrel, Alain

Gene expression profiling has recently emerged as a promising approach to identify early target genes and discriminate genotoxic carcinogens from non-genotoxic carcinogens and non-carcinogens. However, early gene changes induced by genotoxic compounds in human liver remain largely unknown. Primary human hepatocytes and differentiated HepaRG cells were exposed to aflatoxin B1 (AFB1) that induces DNA damage following enzyme-mediated bioactivation. Gene expression profile changes induced by a 24 h exposure of these hepatocyte models to 0.05 and 0.25 μM AFB1 were analyzed by using oligonucleotide pangenomic microarrays. The main altered signaling pathway was the p53 pathway and related functions such as cellmore » cycle, apoptosis and DNA repair. Direct involvement of the p53 protein in response to AFB1 was verified by using siRNA directed against p53. Among the 83 well-annotated genes commonly modulated in two pools of three human hepatocyte populations and HepaRG cells, several genes were identified as altered by AFB1 for the first time. In addition, a subset of 10 AFB1-altered genes, selected upon basis of their function or tumor suppressor role, was tested in four human hepatocyte populations and in response to other chemicals. Although they exhibited large variable inter-donor fold-changes, several of these genes, particularly FHIT, BCAS3 and SMYD3, were found to be altered by various direct and other indirect genotoxic compounds and unaffected by non-genotoxic compounds. Overall, this comprehensive analysis of early gene expression changes induced by AFB1 in human hepatocytes identified a gene subset that included several genes representing potential biomarkers of genotoxic compounds. -- Highlights: ► Gene expression profile changes induced by aflatoxin B1 in human hepatocytes. ► AFB1 modulates various genes including tumor suppressor genes and proto-oncogenes. ► Important inter-individual variations in the response to AFB1. ► Some genes also altered by other genotoxic compounds requiring or not bioactivation.« less

Micronucleus assay in aquatic animals.

PubMed

Bolognesi, Claudia; Hayashi, Makoto

2011-01-01

Aquatic pollutants produce multiple consequences at organism, population, community and ecosystem level, affecting organ function, reproductive status, population size, species survival and thus biodiversity. Among these, carcinogenic and mutagenic compounds are the most dangerous as their effects may exert a damage beyond that of individual and may be active through several generations. The application of genotoxicity biomarkers in sentinel organisms allows for the assessment of mutagenic hazards and/or for the identification of the sources and fate of the contaminants. Micronucleus (MN) test as an index of accumulated genetic damage during the lifespan of the cells is one of the most suitable techniques to identify integrated response to the complex mixture of contaminants. MN assay is today widely applied in a large number of wild and transplanted aquatic species. The large majority of studies or programmes on the genotoxic effect of the polluted water environment have been carried out with the use of bivalves and fish. Haemocytes and gill cells are the target tissues most frequently considered for the MN determination in bivalves. The MN test was widely validated and was successfully applied in a large number of field studies using bivalves from the genera Mytilus. MN in fish can be visualised in different cell types: erythrocytes and gill, kidney, hepatic and fin cells. The use of peripheral erythrocytes is more widely used because it avoids the complex cell preparation and the killing of the animals. The MN test in fish erythrocytes was validated in laboratory with different species after exposure to a large number of genotoxic agents. The erythrocyte MN test in fish was also widely and frequently applied for genotoxicity assessment of freshwater and marine environment in situ using native or caged animals following different periods of exposure. Large interspecies differences in sensitivity for MN induction were observed. Further validation studies are needed in order to better characterise the different types of nuclear alterations and to clarify the role of biotic and abiotic factors in interspecies and inter-individual variability.

Genotoxicity potential of a new natural formicide.

PubMed

Cotelle, Sylvie; Testolin, Renan C; Foltête, Anne-Sophie; Bossardi-Rissardi, Georgiana; Silveira, Rosilene A; Radetski, Claudemir M

2012-03-01

Assessment of environmental impacts from pesticide utilization should include genotoxicity studies, where the possible effects of mutagenic/genotoxic substances on individuals are assessed. In this study, the genotoxicity profile of the new formicide Macex® was evaluated with two genotoxicity tests, namely, the micronucleus test with mouse bone marrow and Vicia faba, and a mutagenicity test using the Ames Salmonella assay. The bacterial reverse mutation test (Salmonella typhimurium strains TA97, TA98, TA100, TA102, and TA1535), the Vicia root tip and mouse micronucleus tests were conducted according to published protocols. In the range of the formicide Macex® concentrations tested from 0.06 to 1.0 g L⁻¹ (or mgkg⁻¹ in the mouse test), no genotoxicity was observed in the prokaryotic or eukaryotic test organisms. However, at Macex® concentrations of 0.5 g L⁻¹ and above a significant decrease in the mitotic index (P ≤ 0.05) in the V. faba was observed. Micronucleus formation was likewise increased in the test organism at concentrations starting at 2.0 g L⁻¹. These data allow us to classify this natural formicide preparation as a product with no geno-environmental-impact when applied at recommended concentrations.

Identification of the key pathway of oxazolinoanthracyclines mechanism of action in cells derived from human solid tumors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Denel-Bobrowska, Marta, E-mail: mdenel@biol.uni.lo

Oxazolinodoxorubicin (O-DOX) and oxazolinodaunorubicin (O-DAU) are novel anthracycline derivatives with a modified daunosamine moiety. In the present study, we evaluated the cytotoxicities, genotoxicities and abilities of O-DOX and O-DAU to induce apoptosis in cancer cell lines (SKOV-3; A549; HepG2), and compared the results with their parent drugs. We assessed antiproliferative activity by MTT assay. We evaluated apoptosis-inducing ability by double-staining with fluorescent probes (Hoechst 33258/propidium iodide), and by determining expression levels of genes involved in programmed cell death by reverse transcription-polymerase chain reaction. Genotoxicities of the compounds were tested by comet assays. Oxazolinoanthracyclines demonstrated high anti-tumor activity. O-DOX had significantlymore » higher cytotoxicity, apoptosis-inducing ability, and genotoxicity compared with parental doxorubicin (DOX) in all tested conditions, while O-DAU activity differed among cell lines. The mechanism of oxazoline analog action appeared to involve the mitochondrial pathway of programmed cell death. These results provide further information about oxazoline derivatives of commonly used anthracycline chemotherapy agents. O-DOX and O-DAU have the ability to induce apoptosis in tumor cells. - Highlights: • Substituted amino group increased the anticancer activity of anthracyclines. • Mitochondrial apoptotic pathway seems to be involved in the mechanism of action. • Favorable biological properties of oxazoline derivatives were confirmed.« less

Mutagenicity of silver nanoparticles in CHO cells dependent on particle surface functionalization and metabolic activation

NASA Astrophysics Data System (ADS)

Guigas, Claudia; Walz, Elke; Gräf, Volker; Heller, Knut J.; Greiner, Ralf

2017-06-01

The potential of engineered nanomaterials to induce genotoxic effects is an important aspect of hazard identification. In this study, cytotoxicity and mutagenicity as a function of metabolic activation of three silver nanoparticle (AgNP) preparations differing in surface coating were determined in Chinese hamster ovary (CHO) subclone K1 cells. Three silver nanoparticle preparations ( x 90,0 <30 nm) stabilized with polyoxyethylene glycerol trioleate and polyoxyethylene sorbitan monolaurate (AgPure™), citrate (Citrate-Ag), and polyvinylpyrrolidone (PVP-Ag) were used for the experiments. The cytotoxic effect of AgNPs was assessed with the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazoliumbromide) test using different concentrations of nanoparticles, while the mutagenicity was evaluated using the hypoxanthine-guanine phosphoribosyltransferase (HPRT) gene mutation assay. The cytotoxicity of all three AgNPs was lower in a cell culture medium containing 10% fetal calf serum (FCS) than in medium without FCS. The HPRT test without metabolic activation system S9 revealed that compared to the other AgNP formulations, citrate-coated Ag showed a lower genotoxic effect. However, addition of S9 increased the mutation frequency of all AgNPs and especially influenced the genotoxicity of Citrate-Ag. The results showed that exogenous metabolic activation of nanosilver is crucial even if interactions of the metabolic activation system, nanosilver, and cells are not really understood up to now.

Assessment of the in vitro and in vivo genotoxicity of extracts and indole monoterpene alkaloid from the roots of Galianthe thalictroides (Rubiaceae).

PubMed

Fernandes, L M; Garcez, W S; Mantovani, M S; Figueiredo, P O; Fernandes, C A; Garcez, F R; Guterres, Z R

2013-09-01

Roots of Galianthe thalictroides K. Schum. (Rubiaceae) are used in folk medicine in the State of Mato Grosso do Sul, Brazil, for treating and preventing cancer. To gain information about the genotoxicity of extracts (aqueous and EtOH), the CHCl₃ phase resulting from partition of the EtOH extract and the indole monoterpene alkaloid 1 obtained from this plant. The genotoxicity of 1 and extracts was evaluated in vivo through the Drosophila melanogaster wing Somatic Mutation and Recombination Test - SMART, while in vitro cytotoxic (MTT) and Comet assays were performed only with alkaloid 1. The results obtained with the SMART test indicated that the aqueous extract had no genotoxic activity. The EtOH extract was not genotoxic to ST descendants but genotoxic to HB ones. The CHCl₃ phase was genotoxic and cytotoxic. Alkaloid 1 showed significant mutational events with SMART, in the cytotoxicity assay (MTT), it showed a high cytotoxicity for human hepatoma cells (HepG2), whereas for the Comet assay, not showing genotoxic activity. The ethanol extract was shown to be genotoxic to HB descendants in the SMART assay, while the results obtained in this test for the monoterpene indole alkaloid 1 isolated from this extract. Copyright © 2013 Elsevier Ltd. All rights reserved.

The micronucleus test-most widely used in vivo genotoxicity test.

PubMed

Hayashi, Makoto

2016-01-01

Genotoxicity is commonly evaluated during the chemical safety assessment together with other toxicological endpoints. The micronucleus test is always included in many genotoxic test guidelines for long time in many classes of chemicals, e.g., pharmaceutical chemicals, agricultural chemicals, food additives. Although the trend of the safety assessment of chemicals faces to animal welfare and in vitro systems are more welcome than the in vivo systems, the in vivo test systems are paid more attention in the field of genotoxicity because of its weight of evidence. In this review, I will summarize the following points: 1) historical consideration of the test development, 2) characteristics of the test including advantages and limitations, 3) new approaches considering to the animal welfare.

Gene toxicity studies on titanium dioxide and zinc oxide nanomaterials used for UV-protection in cosmetic formulations.

PubMed

Landsiedel, Robert; Ma-Hock, Lan; Van Ravenzwaay, Ben; Schulz, Markus; Wiench, Karin; Champ, Samantha; Schulte, Stefan; Wohlleben, Wendel; Oesch, Franz

2010-12-01

Titanium dioxide and zinc oxide nanomaterials, used as UV protecting agents in sunscreens, were investigated for their potential genotoxicity in in vitro and in vivo test systems. Since standard OECD test methods are designed for soluble materials and genotoxicity testing for nanomaterials is still under revision, a battery of standard tests was used, covering different endpoints. Additionally, a procedure to disperse the nanomaterials in the test media and careful characterization of the dispersed test item was added to the testing methods. No genotoxicity was observed in vitro (Ames' Salmonella gene mutation test and V79 micronucleus chromosome mutation test) or in vivo (mouse bone marrow micronucleus test and Comet DNA damage assay in lung cells from rats exposed by inhalation). These results add to the still limited data base on genotoxicity test results with nanomaterials and provide congruent results of a battery of standard OECD test methods applied to nanomaterials.

Investigating the different mechanisms of genotoxic and non-genotoxic carcinogens by a gene set analysis.

PubMed

Lee, Won Jun; Kim, Sang Cheol; Lee, Seul Ji; Lee, Jeongmi; Park, Jeong Hill; Yu, Kyung-Sang; Lim, Johan; Kwon, Sung Won

2014-01-01

Based on the process of carcinogenesis, carcinogens are classified as either genotoxic or non-genotoxic. In contrast to non-genotoxic carcinogens, many genotoxic carcinogens have been reported to cause tumor in carcinogenic bioassays in animals. Thus evaluating the genotoxicity potential of chemicals is important to discriminate genotoxic from non-genotoxic carcinogens for health care and pharmaceutical industry safety. Additionally, investigating the difference between the mechanisms of genotoxic and non-genotoxic carcinogens could provide the foundation for a mechanism-based classification for unknown compounds. In this study, we investigated the gene expression of HepG2 cells treated with genotoxic or non-genotoxic carcinogens and compared their mechanisms of action. To enhance our understanding of the differences in the mechanisms of genotoxic and non-genotoxic carcinogens, we implemented a gene set analysis using 12 compounds for the training set (12, 24, 48 h) and validated significant gene sets using 22 compounds for the test set (24, 48 h). For a direct biological translation, we conducted a gene set analysis using Globaltest and selected significant gene sets. To validate the results, training and test compounds were predicted by the significant gene sets using a prediction analysis for microarrays (PAM). Finally, we obtained 6 gene sets, including sets enriched for genes involved in the adherens junction, bladder cancer, p53 signaling pathway, pathways in cancer, peroxisome and RNA degradation. Among the 6 gene sets, the bladder cancer and p53 signaling pathway sets were significant at 12, 24 and 48 h. We also found that the DDB2, RRM2B and GADD45A, genes related to the repair and damage prevention of DNA, were consistently up-regulated for genotoxic carcinogens. Our results suggest that a gene set analysis could provide a robust tool in the investigation of the different mechanisms of genotoxic and non-genotoxic carcinogens and construct a more detailed understanding of the perturbation of significant pathways.

Investigating the Different Mechanisms of Genotoxic and Non-Genotoxic Carcinogens by a Gene Set Analysis

PubMed Central

Lee, Won Jun; Kim, Sang Cheol; Lee, Seul Ji; Lee, Jeongmi; Park, Jeong Hill; Yu, Kyung-Sang; Lim, Johan; Kwon, Sung Won

2014-01-01

Based on the process of carcinogenesis, carcinogens are classified as either genotoxic or non-genotoxic. In contrast to non-genotoxic carcinogens, many genotoxic carcinogens have been reported to cause tumor in carcinogenic bioassays in animals. Thus evaluating the genotoxicity potential of chemicals is important to discriminate genotoxic from non-genotoxic carcinogens for health care and pharmaceutical industry safety. Additionally, investigating the difference between the mechanisms of genotoxic and non-genotoxic carcinogens could provide the foundation for a mechanism-based classification for unknown compounds. In this study, we investigated the gene expression of HepG2 cells treated with genotoxic or non-genotoxic carcinogens and compared their mechanisms of action. To enhance our understanding of the differences in the mechanisms of genotoxic and non-genotoxic carcinogens, we implemented a gene set analysis using 12 compounds for the training set (12, 24, 48 h) and validated significant gene sets using 22 compounds for the test set (24, 48 h). For a direct biological translation, we conducted a gene set analysis using Globaltest and selected significant gene sets. To validate the results, training and test compounds were predicted by the significant gene sets using a prediction analysis for microarrays (PAM). Finally, we obtained 6 gene sets, including sets enriched for genes involved in the adherens junction, bladder cancer, p53 signaling pathway, pathways in cancer, peroxisome and RNA degradation. Among the 6 gene sets, the bladder cancer and p53 signaling pathway sets were significant at 12, 24 and 48 h. We also found that the DDB2, RRM2B and GADD45A, genes related to the repair and damage prevention of DNA, were consistently up-regulated for genotoxic carcinogens. Our results suggest that a gene set analysis could provide a robust tool in the investigation of the different mechanisms of genotoxic and non-genotoxic carcinogens and construct a more detailed understanding of the perturbation of significant pathways. PMID:24497971

A novel toxicogenomics-based approach to categorize (non-)genotoxic carcinogens.

PubMed

Schaap, Mirjam M; Wackers, Paul F K; Zwart, Edwin P; Huijskens, Ilse; Jonker, Martijs J; Hendriks, Giel; Breit, Timo M; van Steeg, Harry; van de Water, Bob; Luijten, Mirjam

2015-12-01

Alternative methods to detect non-genotoxic carcinogens are urgently needed, as this class of carcinogens goes undetected in the current testing strategy for carcinogenicity under REACH. A complicating factor is that non-genotoxic carcinogens act through several distinctive modes of action, which makes prediction of their carcinogenic property difficult. We have recently demonstrated that gene expression profiling in primary mouse hepatocytes is a useful approach to categorize non-genotoxic carcinogens according to their modes of action. In the current study, we improved the methods used for analysis and added mouse embryonic stem cells as a second in vitro test system, because of their features complementary to hepatocytes. Our approach involved an unsupervised analysis based on the 30 most significantly up- and down-regulated genes per chemical. Mouse embryonic stem cells and primary mouse hepatocytes were exposed to a selected set of chemicals and subsequently subjected to gene expression profiling. We focused on non-genotoxic carcinogens, but also included genotoxic carcinogens and non-carcinogens to test the robustness of this approach. Application of the optimized comparison approach resulted in improved categorization of non-genotoxic carcinogens. Mouse embryonic stem cells were a useful addition, especially for genotoxic substances, but also for detection of non-genotoxic carcinogens that went undetected by primary hepatocytes. The approach presented here is an important step forward to categorize chemicals, especially those that are carcinogenic.

Assessment of genotoxicity of herbal medicinal products: application of the "bracketing and matrixing" concept using the example of Valerianae radix (valerian root).

PubMed

Kelber, Olaf; Wegener, Tankred; Steinhoff, Barbara; Staiger, Christiane; Wiesner, Jacqueline; Knöss, Werner; Kraft, Karin

2014-01-01

An assessment of genotoxicity is a precondition for marketing authorization respectively registration of herbal medicinal products (HMPs), as well as for inclusion into the 'Community list of herbal substances, preparations and combinations thereof for use in traditional herbal medicinal products' established by the European Commission in accordance with Directive 2001/83/EC as amended, and based on proposals from the Committee on Herbal Medicinal Products (HMPC). In the 'Guideline on the assessment of genotoxicity of herbal substances/preparations' (EMEA/HMPC/107079/2007) HMPC has described a stepwise approach for genotoxicity testing, according to which the Ames test is a sufficient base for the assessment of genotoxicity in case of an unequivocally negative result. For reducing efforts for testing of individual herbal substances/preparations, HMPC has also developed the 'guideline on selection of test materials for genotoxicity testing for traditional herbal medicinal products/herbal medicinal products' (EMEA/HMPC/67644/2009) with the aim to allow testing of a standard range of test materials which could be considered representative of the commonly used preparations from a specific herbal drug according to a 'bracketing/matrixing' approach. The purpose of this paper is to provide data on the practical application of this bracketing and matrixing concept using the example of Valerianae radix, with the intention of facilitating its inclusion in the "Community list". Five extraction solvents, representing the extremes of the polarity range and including also mid-range extraction solvents, were used, covering the entire spectrum of phytochemical constituents of Valerianae radix, thereby including polar and non-polar constituents. Extracts were tested in the Ames test according to all relevant guidelines. Results were unequivocally negative for all extracts. A review of the literature showed that this result is in accordance with the available data, thus demonstrating the lack of a genotoxic potential. In conclusion the two guidelines on genotoxicity provide a practically applicable concept. Valerianae radix has no genotoxic potential, supporting its use in HMPs and its inclusion in the Community list. Copyright © 2014 The Authors. Published by Elsevier GmbH.. All rights reserved.

GENOTOXICITY OF TEN CIGARETTE SMOKE CONDENSATES IN FOUR TEST SYSTEMS: COMPARISONS AMONG ASSAYS AND CONDENSATES

EPA Science Inventory

The particulate fraction of cigarette smoke, cigarette smoke condensate (CSC), is genotoxic in many short-term in vitro tests and carcinogenic in rodents. However, no study has evaluatedd a set of CSCs prepared from a diverse set of cigarettes in a variety of short-term genotoxic...

Genotoxicity of AMPA, the environmental metabolite of glyphosate, assessed by the Comet assay and cytogenetic tests.

PubMed

Mañas, F; Peralta, L; Raviolo, J; García Ovando, H; Weyers, A; Ugnia, L; Gonzalez Cid, M; Larripa, I; Gorla, N

2009-03-01

Formulations containing glyphosate are the most widely used herbicides in the world. AMPA is the major environmental breakdown product of glyphosate. The purpose of this study is to evaluate the in vitro genotoxicity of AMPA using the Comet assay in Hep-2 cells after 4h of incubation and the chromosome aberration (CA) test in human lymphocytes after 48h of exposition. Potential in vivo genotoxicity was evaluated through the micronucleus test in mice. In the Comet assay, the level of DNA damage in exposed cells at 2.5-7.5mM showed a significant increase compared with the control group. In human lymphocytes we found statistically significant clastogenic effect AMPA at 1.8mM compared with the control group. In vivo, the micronucleus test rendered significant statistical increases at 200-400mg/kg. AMPA was genotoxic in the three performed tests. Very scarce data are available about AMPA potential genotoxicity.

Evaluation of the GADD45α-GFP GreenScreen HC assay for rapid and reliable in vitro early genotoxicity screening.

PubMed

Luzy, Anne-Pascale; Orsini, Nicolas; Linget, Jean-Michel; Bouvier, Guy

2013-11-01

Twenty-two of Galderma's proprietary compounds were tested in the GADD45α-GFP 'GreenScreen HC' assay (GS), the SOS-ChromoTest and the Mini-Ames to evaluate GSs performance for early genotoxicity screening purposes. Forty more characterized compounds were also tested, including antibiotics: metronidazole, clindamycin, tetracycline, lymecycline and neomycin; and catecholamines: resorcinol mequinol, hydroquinone, one aneugen carbendazim, one corticoid dexamethasone, one peroxisome proliferator-activated receptor rosiglitazone, one pesticide carbaryl and two further proprietary molecules with in vitro genotoxicity data. With proprietary molecules, this study concluded that the GS renders the SOS-ChromoTest obsolete for in vitro screening. The GS confirmed all results of the Mini-Ames test (100% concordance). Compared with the micronucleus test, the GS showed a concordance of 82%. With known compounds, the GS ranked the potency of positive results for catecholamines in accordance with other genotoxicity tests and showed very reproducible results. It confirmed positive results for carbendazim, for tetracycline antibiotics and for carbaryl. The GS produced negative results for metronidazole, a nitroreduction-specific bacterial mutagen, for dexamethasone (a non-genotoxic apoptosis inducer), for rosiglitazone (a GADD45γ promoter inducer) and for clindamycin and neomycin (inhibitors of macromolecular synthesis in bacteria). As such, the GS appears to be a reproducible, robust, specific and sensitive test for genotoxicity screening. Copyright © 2012 John Wiley & Sons, Ltd.

Evaluation of genotoxicity testing of FDA approved large molecule therapeutics.

PubMed

Sawant, Satin G; Fielden, Mark R; Black, Kurt A

2014-10-01

Large molecule therapeutics (MW>1000daltons) are not expected to enter the cell and thus have reduced potential to interact directly with DNA or related physiological processes. Genotoxicity studies are therefore not relevant and typically not required for large molecule therapeutic candidates. Regulatory guidance supports this approach; however there are examples of marketed large molecule therapeutics where sponsors have conducted genotoxicity studies. A retrospective analysis was performed on genotoxicity studies of United States FDA approved large molecule therapeutics since 1998 identified through the Drugs@FDA website. This information was used to provide a data-driven rationale for genotoxicity evaluations of large molecule therapeutics. Fifty-three of the 99 therapeutics identified were tested for genotoxic potential. None of the therapeutics tested showed a positive outcome in any study except the peptide glucagon (GlucaGen®) showing equivocal in vitro results, as stated in the product labeling. Scientific rationale and data from this review indicate that testing of a majority of large molecule modalities do not add value to risk assessment and support current regulatory guidance. Similarly, the data do not support testing of peptides containing only natural amino acids. Peptides containing non-natural amino acids and small molecules in conjugated products may need to be tested. Copyright © 2014 Elsevier Inc. All rights reserved.

Genotoxicity of 1,3-dichloro-2-propanol in the SOS chromotest and in the Ames test. Elucidation of the genotoxic mechanism.

PubMed

Hahn, H; Eder, E; Deininger, C

1991-01-01

1,3-Dichloro-2-propanol (1,3-DCP-OH, glycerol dichlorohydrin) is of great importance in many industrial processes and has been detected in foodstuffs, in particular in soup spices and instant soups. It has been shown to be carcinogenic, genotoxic and mutagenic. Its genotoxic mechanisms are, however, not yet entirely understood. We have investigated whether alcohol dehydrogenase (ADH) catalysed activation to the highly mutagenic and carcinogenic 1,3-dichloroacetone or formation of epichlorohydrin or other genotoxic compounds play a role for mutagenicity and genotoxicity. In our studies, no indications of ADH catalysed formation of 1,3-dichloropropane could be found, although we could demonstrate a clear activation by ADH in the case of 2-chloropropenol. Formation of allyl chloride could also be excluded. We found, however, clear evidence that epichlorohydrin formed chemically in the buffer and medium used in the test is responsible for genotoxicity. No indication was found that enzymatic formation of epichlorohydrin plays a role. Additional mutagenicity and genotoxicity studies with epichlorohydrin also confirmed the hypothesis that genotoxic effects of 1,3-DCP-OH depend on the chemical formation of epichlorohydrin.

The current limitations of in vitro genotoxicity testing and their relevance to the in vivo situation.

PubMed

Nesslany, Fabrice

2017-08-01

The standard regulatory core battery of genotoxicity tests generally includes 2 or 3 validated tests with at least one in vitro test in bacteria and one in vitro test on cell cultures. However, limitations in in vitro genotoxicity testing may exist at many levels. The knowledge of the underlying mechanisms of genotoxicity is particularly useful to assess the level of relevance for the in vivo situation. In order to avoid wrong conclusions regarding the actual genotoxicity status of any test substance, it appears very important to be aware of the various origins of related bias leading to 'false positives and negatives' by using in vitro methods. Among these, mention may be made on the metabolic activation system, experimental (extreme) conditions, specificities of the test systems implemented, cell type used etc. The knowledge of the actual 'limits' of the in vitro test systems used is clearly an advantage and may contribute to avoid some pitfalls in order to better assess the level of relevance for the in vivo situation. Copyright © 2016. Published by Elsevier Ltd.

Current investigations into the genotoxicity of zinc oxide and silica nanoparticles in mammalian models in vitro and in vivo: carcinogenic/genotoxic potential, relevant mechanisms and biomarkers, artifacts, and limitations

PubMed Central

Kwon, Jee Young; Koedrith, Preeyaporn; Seo, Young Rok

2014-01-01

Engineered nanoparticles (NPs) are widely used in many sectors, such as food, medicine, military, and sport, but their unique characteristics may cause deleterious health effects. Close attention is being paid to metal NP genotoxicity; however, NP genotoxic/carcinogenic effects and the underlying mechanisms remain to be elucidated. In this review, we address some metal and metal oxide NPs of interest and current genotoxicity tests in vitro and in vivo. Metal NPs can cause DNA damage such as chromosomal aberrations, DNA strand breaks, oxidative DNA damage, and mutations. We also discuss several parameters that may affect genotoxic response, including physicochemical properties, widely used assays/end point tests, and experimental conditions. Although potential biomarkers of nanogenotoxicity or carcinogenicity are suggested, inconsistent findings in the literature render results inconclusive due to a variety of factors. Advantages and limitations related to different methods for investigating genotoxicity are described, and future directions and recommendations for better understanding genotoxic potential are addressed. PMID:25565845

IDENTIFICATION OF THE ROLE OF APOPTOSIS PATHWAYS POTENTIALLY INVOLVED IN FORMALDEHYDE-INDUCED CARCINOGENESIS USING CDNA ARRAYS

EPA Science Inventory

Identification of the Role of Apoptosis Pathways Potentially Involved in Formaldehyde- Induced Carcinogenesis Using cDNA Arrays.

Formaldehyde (FA) is a genotoxic chemical found in household, medicinal, and industrial products. Although the major source of human exposure is...

Quantitative genotoxicity assays for analysis of medicinal plants: A systematic review.

PubMed

Sponchiado, Graziela; Adam, Mônica Lucia; Silva, Caroline Dadalt; Soley, Bruna Silva; de Mello-Sampayo, Cristina; Cabrini, Daniela Almeida; Correr, Cassyano Januário; Otuki, Michel Fleith

2016-02-03

Medicinal plants are known to contain numerous biologically active compounds, and although they have proven pharmacological properties, they can cause harm, including DNA damage. Review the literature to evaluate the genotoxicity risk of medicinal plants, explore the genotoxicity assays most used and compare these to the current legal requirements. A quantitative systematic review of the literature, using the keywords "medicinal plants", "genotoxicity" and "mutagenicity", was undertakenQ to identify the types of assays most used to assess genotoxicity, and to evaluate the genotoxicity potential of medicinal plant extracts. The database searches retrieved 2289 records, 458 of which met the inclusion criteria. Evaluation of the selected articles showed a total of 24 different assays used for an assessment of medicinal plant extract genotoxicity. More than a quarter of those studies (28.4%) reported positive results for genotoxicity. This review demonstrates that a range of genotoxicity assay methods are used to evaluate the genotoxicity potential of medicinal plant extracts. The most used methods are those recommended by regulatory agencies. However, based on the current findings, in order to conduct a thorough study concerning the possible genotoxic effects of a medicinal plant, we indicate that it is important always to include bacterial and mammalian tests, with at least one in vivo assay. Also, these tests should be capable of detecting outcomes that include mutation induction, clastogenic and aneugenic effects, and structural chromosome abnormalities. In addition, the considerable rate of positive results detected in this analysis further supports the relevance of assessing the genotoxicity potential of medicinal plants. Copyright © 2016. Published by Elsevier Ireland Ltd.

A tiered approach to the use of alternatives to animal testing for the safety assessment of cosmetics: genotoxicity. A COLIPA analysis.

PubMed

Pfuhler, Stefan; Kirst, Annette; Aardema, Marilyn; Banduhn, Norbert; Goebel, Carsten; Araki, Daisuke; Costabel-Farkas, Margit; Dufour, Eric; Fautz, Rolf; Harvey, James; Hewitt, Nicola J; Hibatallah, Jalila; Carmichael, Paul; Macfarlane, Martin; Reisinger, Kerstin; Rowland, Joanna; Schellauf, Florian; Schepky, Andreas; Scheel, Julia

2010-01-01

For the assessment of genotoxic effects of cosmetic ingredients, a number of well-established and regulatory accepted in vitro assays are in place. A caveat to the use of these assays is their relatively low specificity and high rate of false or misleading positive results. Due to the 7th amendment to the EU Cosmetics Directive ban on in vivo genotoxicity testing for cosmetics that was enacted March 2009, it is no longer possible to conduct follow-up in vivo genotoxicity tests for cosmetic ingredients positive in in vitro genotoxicity tests to further assess the relevance of the in vitro findings. COLIPA, the European Cosmetics Association, has initiated a research programme to improve existing and develop new in vitro methods. A COLIPA workshop was held in Brussels in April 2008 to analyse the best possible use of available methods and approaches to enable a sound assessment of the genotoxic hazard of cosmetic ingredients. Common approaches of cosmetic companies are described, with recommendations for evaluating in vitro genotoxins using non-animal approaches. A weight of evidence approach was employed to set up a decision-tree for the integration of alternative methods into tiered testing strategies. Copyright 2010 Elsevier Inc. All rights reserved.

Recent Advances in In Vivo Genotoxicity Testing: Prediction of Carcinogenic Potential Using Comet and Micronucleus Assay in Animal Models

PubMed Central

Kang, Seung Hun; Kwon, Jee Young; Lee, Jong Kwon; Seo, Young Rok

2013-01-01

Genotoxic events have been known as crucial step in the initiation of cancer. To assess the risk of cancer, genotoxicity assays, including comet, micronucleus (MN), chromosomal aberration, bacterial reverse, and sister chromatid exchange assay, can be performed. Compared with in vitro genotoxicity assay, in vivo genotoxicity assay has been used to verify in vitro assay result and definitely provide biological significance for certain organs or cell types. The comet assay can detect DNA strand breaks as markers of genotoxicity. Methods of the in vivo comet assay have been established by Japanese Center for the Validation of Alternative Methods (JaCVAM) validation studies depending on tissue and sample types. The MN can be initiated by segregation error and lagging acentric chromosome fragment. Methods of the in vivo MN assay have been established by Organization for Economic Co-operation and Development (OECD) test guidelines and many studies. Combining the in vivo comet and MN assay has been regarded as useful methodology for evaluating genetic damage, and it has been used in the assessment of potential carcinogenicity by complementarily presenting two distinct endpoints of the in vivo genotoxicity individual test. Few studies have investigated the quantitative relation between in vivo genotoxicity results and carcinogenicity. Extensive studies emphasizes that positive correlation is detectable. This review summarizes the results of the in vivo comet and MN assays that have investigated the genotoxicity of carcinogens as classified by the International Agency for Research on Cancer (IARC) carcinogenicity database. As a result, these genotoxicity data may provide meaningful information for the assessment of potential carcinogenicity and for implementation in the prevention of cancer. PMID:25337557

Toxicological and analytical investigations of noni (Morinda citrifolia) fruit juice.

PubMed

Westendorf, Johannes; Effenberger, Katharina; Iznaguen, Hassan; Basar, Simla

2007-01-24

Morinda citrifolia (noni) is known to contain genotoxic anthraquinones in the roots. Because of the widespread use of noni juice, the possible genotoxic risk was examined through a battery of short-term tests. Noni juice was also chemically analyzed for the possible presence of anthraquinones. Noni juice extract in the Salmonella microsome assay showed a slight mutagenic effect in strain TA1537, due to the presence of flavonoids. No mutagenicity was observed in the mammalian mutagenicity test with V79 Chinese hamster fibroblasts. Rats treated with a noni juice concentrate did not show DNA repair synthesis (UDS) in primary rat hepatocytes, nor could DNA adducts or DNA strand breaks be observed. HPLC analysis of noni juice for anthraquinones was negative, with a sensitivity of <1 ppm. In summary, chemical analysis and genotoxicity tests reveal that noni juice does not have a genotoxic potential and that genotoxic anthraquinones do not exist in noni juice.

Genotoxicity investigations on nanomaterials.

PubMed

Oesch, Franz; Landsiedel, Robert

2012-07-01

This review is based on the lecture presented at the April 2010 nanomaterials safety assessment Postsatellite to the 2009 EUROTOX Meeting and summarizes genotoxicity investigations on nanomaterials published in the open scientific literature (up to 2008). Special attention is paid to the relationship between particle size and positive versus negative outcome, as well as the dependence of the outcome on the test used. Salient conclusions and outstanding recommendations emerging from the information summarized in this review are as follows: recognize that nanomaterials are not all the same; therefore know and document what nanomaterial has been tested and in what form; take nanomaterials specific properties into account; in order to make your results comparable with those of others and on other nanomaterials: use or at least include in your studies standardized methods; use in vivo studies to put in vitro results into perspective; take uptake and distribution of the nanomaterial into account; and in order to become able to make extrapolations to risk for human: learn about the mechanism of nanomaterials genotoxic effects. Past experience with standard non-nanosubstances already had shown that mechanisms of genotoxic effects can be complex and their elucidation can be demanding, while there often is an immediate need to assess the genotoxic hazard. Thus, a practical and pragmatic approach to genotoxicity investigations of novel nanomaterials is the use of a battery of standard genotoxicity testing methods covering a wide range of mechanisms. Application of these standard methods to nanomaterials demands, however, adaptations, and the interpretation of results from the genotoxicity testing of nanomaterials needs additional considerations exceeding those used for standard size materials.

Prediction of Chemical Carcinogenicity in Rodents from in vitro Genetic Toxicity Assays

NASA Astrophysics Data System (ADS)

Tennant, Raymond W.; Margolin, Barry H.; Shelby, Michael D.; Zeiger, Errol; Haseman, Joseph K.; Spalding, Judson; Caspary, William; Resnick, Michael; Stasiewicz, Stanley; Anderson, Beth; Minor, Robert

1987-05-01

Four widely used in vitro assays for genetic toxicity were evaluated for their ability to predict the carcinogenicity of selected chemicals in rodents. These assays were mutagenesis in Salmonella and mouse lymphoma cells and chromosome aberrations and sister chromatid exchanges in Chinese hamster ovary cells. Seventy-three chemicals recently tested in 2-year carcinogenicity studies conducted by the National Cancer Institute and the National Toxicology Program were used in this evaluation. Test results from the four in vitro assays did not show significant differences in individual concordance with the rodent carcinogenicity results; the concordance of each assay was approximately 60 percent. Within the limits of this study there was no evidence of complementarity among the four assays, and no battery of tests constructed from these assays improved substantially on the overall performance of the Salmonella assay. The in vitro assays which represented a range of three cell types and four end points did show substantial agreement among themselves, indicating that chemicals positive in one in vitro assay tended to be positive in the other in vitro assays. To help put this project into its proper context, we emphasize certain features of the study: 1) Standard protocols were used to mimic the major use of STTs worldwide--screening for mutagens and carcinogens; no attempt was made to optimize protocols for specific chemicals. 2) The 73 NTP chemicals and their 60% incidence of carcinogenicity are probably not representative of the universe of chemicals but rather reflect the recent chemical selection process for the NTP carcinogenicity assay. 3) The small, diverse group of chemicals precludes a meaningful evaluation of the predictive utility of chemical structure information. 4) The NTP is currently testing these same 73 chemicals in two in vivo STTs for chromosomal effects. 5) Complete data for an additional group of 30 to 40 NTP chemicals will be gathered on carcinogenicity and the four in vitro STTs to attempt to confirm the current findings. The standard against which the performance of STTs is measured has changed dramatically in the past decade. The high levels of concordance published in the early 1970s were accurate at the time. Nearly all known carcinogens tested were genotoxic, and there was little experimental evidence on which to base a judgment of noncarcinogenicity which, taken together, restricted assessment of test performances with noncarcinogens. With the increasing availability of results from NCI and NTP 2-year carcinogenicity studies in rodents, higher frequencies of nongenotoxic carcinogens and genotoxic noncarcinogens have been observed; this has resulted in the reduced concordance of the STT results with carcinogenicity results. It is clear that even with a battery of assays, not all rodent carcinogens are in vitro mutagens nor are all in vitro mutagens rodent carcinogens. If current in vitro STTs are expected to replace long-term rodent studies for the identification of chemical carcinogens, then that expectation should be abandoned. STTs do, however, continue to offer an economical, rapid, and dependable means to detect genotoxic chemicals. There is a range of applications in which STTs have been used successfully, from the identification of mutagenic fractions in complex mixtures such as cooked meat (32, 33) or air pollutants (34) to the early identification of genetic toxicity in the development of new chemical products (35). Requirements for the use of STT have not been consistent in both the national and international regulatory agencies. This is evident in the variety of testing requirements (8) and the different impacts that positive test results have on the registration or further testing requirements of chemicals. Consensus on these matters is not likely to occur in the near future, but agreement should be possible in certain areas. For instance, any time a new test or strategy is proposed, it is imperative that there be documentation by a substantial set of systematically acquired test results on well-defined rodent carcinogens and noncarcinogens (36). The current study represents a prototype of the evaluative effort needed for such documentation. Results of the current study focus attention on two questions involving discordances between carcinogenicity and genotoxicity test results: (i) Do nongenotoxic rodent carcinogens pose the same carcinogenic risk to humans as those that are genotoxic? (ii) Can the apparent high frequency of in vitro genotoxic rodent noncarcinogens be explained as a combination of artifacts arising from extremely high dosing in in vitro tests or the failure of many bona fide in vitro genotoxins to express their genetic toxicity in whole animals? Until these questions are resolved, chemicals that show mutagenic effects, particularly if such effects are observed in vivo, must be initially considered to pose human health risks as long as the somatic mutation theory of cancer remains a viable explanation for the etiology of some chemically induced cancers.

Dissecting modes of action of non-genotoxic carcinogens in primary mouse hepatocytes.

PubMed

Schaap, Mirjam M; Zwart, Edwin P; Wackers, Paul F K; Huijskens, Ilse; van de Water, Bob; Breit, Timo M; van Steeg, Harry; Jonker, Martijs J; Luijten, Mirjam

2012-11-01

Under REACH, the European Community Regulation on chemicals, the testing strategy for carcinogenicity is based on in vitro and in vivo genotoxicity assays. Given that non-genotoxic carcinogens are negative for genotoxicity and chronic bioassays are no longer regularly performed, this class of carcinogens will go undetected. Therefore, test systems detecting non-genotoxic carcinogens, or even better their modes of action, are required. Here, we investigated whether gene expression profiling in primary hepatocytes can be used to distinguish different modes of action of non-genotoxic carcinogens. For this, primary mouse hepatocytes were exposed to 16 non-genotoxic carcinogens with diverse modes of action. Upon profiling, pathway analysis was performed to obtain insight into the biological relevance of the observed changes in gene expression. Subsequently, both a supervised and an unsupervised comparison approach were applied to recognize the modes of action at the transcriptomic level. These analyses resulted in the detection of three of eight compound classes, that is, peroxisome proliferators, metalloids and skin tumor promotors. In conclusion, gene expression profiles in primary hepatocytes, at least in rodent hepatocytes, appear to be useful to detect some, certainly not all, modes of action of non-genotoxic carcinogens.

[Genotoxicity of drinking water during chlorine and chloramine disinfection and the influence of disinfection conditions using the umu-test].

PubMed

Liu, Qing; Zhang, Li-Ping; Liu, Wen-Jun; Nie, Xue-Biao; Zhang, Su-Xia; Zhang, Shun

2010-01-01

In this study, the effects of disinfectant dosage, reaction time and the ratio of Cl2 to N of disinfectant on genotoxicity of effluent of ozone-biological activated carbon (O3-BAC) during chlorine or chloramine disinfection were investigated using umu-test. It was found that, the genotoxicity of effluent of O3-BAC before disinfection ranged from 20-70 ng/L, and it increased after disinfection by chlorine or chloramines. With the same reaction time(24 h), genotoxicity after chlorination (40-95 ng/L) was higher than that after chloramination (20-40 ng/L) under same initial dosage. For chlorination, with initial dosage increasing from 0 mg/L to 10 mg/L, genotoxicity increased firstly, and got the maximum value at about 0.5-1 mg/L dosage, then decreased and got the minimum value at about 3-5 mg/L dosage, and finally increased again. For chloramination, genotoxicity didn't change that much. With the dosage of 3 mg/L and reaction time increasing from 0 h to 72 h, no matter for chlorine or chloramines disinfection, genotoxicity of effluent of O3-BAC both increased firstly, and got the maximum value at about 2 h, then decreased and got the minimum value at about 18 h, and finally increased again, and genotoxicity after chlorine disinfection (83-120 ng/L) was higher than that after chloramines disinfection (20-62 ng/L) under same reaction time. Further more, effects of the different ratios of Cl2 to N of disinfectant on genotoxicity of effluent of O3-BAC were also studied. Results of this study demonstrate that under test conditions, chloramine disinfection is safer than chlorine disinfection in the aspect of genotoxicity for drinking water, and the changes of genotoxicity are different from those of total HAAs.

Alumina at 50 and 13 nm nanoparticle sizes have potential genotoxicity.

PubMed

Zhang, Qinli; Wang, Haiyang; Ge, Cuicui; Duncan, Jeremy; He, Kaihong; Adeosun, Samuel O; Xi, Huaxin; Peng, Huiting; Niu, Qiao

2017-09-01

Although nanomaterials have the potential to improve human life, their sideline effects on human health seem to be inevitable and still are unknown. Some studies have investigated the genotoxicity of alumina nanoparticles (AlNPs); however, this effect is still unclear due to insufficient evaluation and conflicting results. Using a battery of standard genotoxic assays, the present study offers evidence of the genotoxicity associated with aluminum oxide (alumina) at NP sizes of 50 and 13 nm, when compared with bulk alumina (10 μm). The genotoxicity induced by alumina at bulk and NP sizes was evaluated with Ames test, comet test, micronucleus assay and sperm deformity test. The mechanism related to the induction of reactive oxygen species was explored as well. Our results showed that AlNPs (13 and 50 nm) were able to enter cells and induced DNA damage, micronucleus in bone marrow, sperm deformation and reactive oxygen species induction in a time-, dose- and size-dependent manner. Therefore, we conclude that AlNPs (13 and 50 nm), rather than bulk alumina, induce markers of genotoxicity in mice, with oxidative stress as a potential mechanism driving these genotoxic effects. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

Use of a standardized JaCVAM in vivo rat comet assay protocol to assess the genotoxicity of three coded test compounds; ampicillin trihydrate, 1,2-dimethylhydrazine dihydrochloride, and N-nitrosodimethylamine.

PubMed

McNamee, J P; Bellier, P V

2015-07-01

As part of the Japanese Center for the Validation of Alternative Methods (JaCVAM)-initiative international validation study of the in vivo rat alkaline comet assay (comet assay), our laboratory examined ampicillin trihydrate (AMP), 1,2-dimethylhydrazine dihydrochloride (DMH), and N-nitrosodimethylamine (NDA) using a standard comet assay validation protocol (v14.2) developed by the JaCVAM validation management team (VMT). Coded samples were received by our laboratory along with basic MSDS information. Solubility analysis and range-finding experiments of the coded test compounds were conducted for dose selection. Animal dosing schedules, the comet assay processing and analysis, and statistical analysis were conducted in accordance with the standard protocol. Based upon our blinded evaluation, AMP was not found to exhibit evidence of genotoxicity in either the rat liver or stomach. However, both NDA and DMH were observed to cause a significant increase in % tail DNA in the rat liver at all dose levels tested. While acute hepatoxicity was observed for these compounds in the high dose group, in the investigators opinion there were a sufficient number of consistently damaged/measurable cells at the medium and low dose groups to judge these compounds as genotoxic. There was no evidence of genotoxicity from either NDA or DMH in the rat stomach. In conclusion, our laboratory observed increased DNA damage from two blinded test compounds in rat liver (later identified as genotoxic carcinogens), while no evidence of genotoxicity was observed for the third blinded test compound (later identified as a non-genotoxic, non-carcinogen). This data supports the use of a standardized protocol of the in vivo comet assay as a cost-effective alternative genotoxicity assay for regulatory testing purposes. Crown Copyright © 2015. Published by Elsevier B.V. All rights reserved.

Recommended lists of genotoxic and non-genotoxic chemicals for assessment of the performance of new or improved genotoxicity tests: a follow-up to an ECVAM workshop.

PubMed

Kirkland, David; Kasper, Peter; Müller, Lutz; Corvi, Raffaella; Speit, Günter

2008-05-31

At a recent ECVAM workshop considering ways to reduce the frequency of irrelevant positive results in mammalian cell genotoxicity tests [D. Kirkland, S. Pfuhler, D. Tweats, M. Aardema, R. Corvi, F. Darroudi, A. Elhajouji, H.-R. Glatt, P. Hastwell, M. Hayashi, P. Kasper, S. Kirchner, A. Lynch, D. Marzin, D. Maurici, J.-R. Meunier, L. Müller, G. Nohynek, J. Parry, E. Parry, V. Thybaud, R. Tice, J. van Benthem, P. Vanparys, P. White, How to reduce false positive results when undertaking in vitro genotoxicity testing and thus avoid unnecessary followup animal tests: Report of an ECVAM Workshop, Mutat. Res. 628 (2007) 31-55], recommendations for improvements/modifications to existing tests, and suggestions for new assays were made. Following on from this, it was important to identify chemicals that could be used in the evaluation of modified or new assays. An expert panel was therefore convened and recommendations made for chemicals to fit three different sets of characteristics, namely: This paper therefore contains these three recommended lists of chemicals and describes how these should be used for any test-evaluation programme.

Testing chemical carcinogenicity by using a transcriptomics HepaRG-based model?

PubMed Central

Doktorova, T. Y.; Yildirimman, Reha; Ceelen, Liesbeth; Vilardell, Mireia; Vanhaecke, Tamara; Vinken, Mathieu; Ates, Gamze; Heymans, Anja; Gmuender, Hans; Bort, Roque; Corvi, Raffaella; Phrakonkham, Pascal; Li, Ruoya; Mouchet, Nicolas; Chesne, Christophe; van Delft, Joost; Kleinjans, Jos; Castell, Jose; Herwig, Ralf; Rogiers, Vera

2014-01-01

The EU FP6 project carcinoGENOMICS explored the combination of toxicogenomics and in vitro cell culture models for identifying organotypical genotoxic- and non-genotoxic carcinogen-specific gene signatures. Here the performance of its gene classifier, derived from exposure of metabolically competent human HepaRG cells to prototypical non-carcinogens (10 compounds) and hepatocarcinogens (20 compounds), is reported. Analysis of the data at the gene and the pathway level by using independent biostatistical approaches showed a distinct separation of genotoxic from non-genotoxic hepatocarcinogens and non-carcinogens (up to 88 % correct prediction). The most characteristic pathway responding to genotoxic exposure was DNA damage. Interlaboratory reproducibility was assessed by blindly testing of three compounds, from the set of 30 compounds, by three independent laboratories. Subsequent classification of these compounds resulted in correct prediction of the genotoxicants. As expected, results on the non-genotoxic carcinogens and the non-carcinogens were less predictive. In conclusion, the combination of transcriptomics with the HepaRG in vitro cell model provides a potential weight of evidence approach for the evaluation of the genotoxic potential of chemical substances. PMID:26417288

Automation of the in vitro micronucleus and chromosome aberration assay for the assessment of the genotoxicity of the particulate and gas-vapor phase of cigarette smoke.

PubMed

Roemer, Ewald; Zenzen, Volker; Conroy, Lynda L; Luedemann, Kathrin; Dempsey, Ruth; Schunck, Christian; Sticken, Edgar Trelles

2015-01-01

Total particulate matter (TPM) and the gas-vapor phase (GVP) of mainstream smoke from the Reference Cigarette 3R4F were assayed in the cytokinesis-block in vitro micronucleus (MN) assay and the in vitro chromosome aberration (CA) assay, both using V79-4 Chinese hamster lung fibroblasts exposed for up to 24 h. The Metafer image analysis platform was adapted resulting in a fully automated evaluation system of the MN assay for the detection, identification and reporting of cells with micronuclei together with the determination of the cytokinesis-block proliferation index (CBPI) to quantify the treatment-related cytotoxicity. In the CA assay, the same platform was used to identify, map and retrieve metaphases for a subsequent CA evaluation by a trained evaluator. In both the assays, TPM and GVP provoked a significant genotoxic effect: up to 6-fold more micronucleated target cells than in the negative control and up to 10-fold increases in aberrant metaphases. Data variability was lower in the automated version of the MN assay than in the non-automated. It can be estimated that two test substances that differ in their genotoxicity by approximately 30% can statistically be distinguished in the automated MN and CA assays. Time savings, based on man hours, due to the automation were approximately 70% in the MN and 25% in the CA assays. The turn-around time of the evaluation phase could be shortened by 35 and 50%, respectively. Although only cigarette smoke-derived test material has been applied, the technical improvements should be of value for other test substances.

Genotoxicity testing of different types of beverages in the Drosophila wing Somatic Mutation And Recombination Test.

PubMed

Graf, U; Moraga, A A; Castro, R; Díaz Carrillo, E

1994-05-01

Five wines and one brandy of Spanish origin as well as three herbal teas and ordinary black tea were tested for genotoxicity in the wing Somatic Mutation And Recombination Test (SMART) which makes use of the two recessive wing cell markers multiple wing hairs (mwh) and flare (flr3) on the left arm of chromosome 3 of Drosophila melanogaster. 3-day-old larvae trans-heterozygous for these two markers were fed the beverages at different concentrations and for different feeding periods using Drosophila instant medium. Somatic mutations or mitotic recombinations induced in the cells of the wing imaginal discs give rise to mutant single or twin spots on the wing blade of the emerging adult flies showing either the mwh phenotype or/and the flr phenotype. One of the red wines showed a clear genotoxic activity that was not due to its ethanol content. Two herbal teas (Urtica dioica, Achillea millefolium) and black tea (Camellia sinensis) proved to be weakly genotoxic as well. Furthermore, it was shown that quercetin and rutin, two flavonols present in beverages of plant origin, also exhibited weak genotoxic activity in the somatic cells of Drosophila. These results demonstrate that Drosophila in vivo somatic assays can detect the genotoxicity of complex mixtures such as beverages. In particular, it is possible to administer these test materials in the same form as that in which they are normally consumed.

Size- and coating-dependent cytotoxicity and genotoxicity of silver nanoparticles evaluated using in vitro standard assays.

PubMed

Guo, Xiaoqing; Li, Yan; Yan, Jian; Ingle, Taylor; Jones, Margie Yvonne; Mei, Nan; Boudreau, Mary D; Cunningham, Candice K; Abbas, Mazhar; Paredes, Angel M; Zhou, Tong; Moore, Martha M; Howard, Paul C; Chen, Tao

2016-11-01

The physicochemical characteristics of silver nanoparticles (AgNPs) may greatly alter their toxicological potential. To explore the effects of size and coating on the cytotoxicity and genotoxicity of AgNPs, six different types of AgNPs, having three different sizes and two different coatings, were investigated using the Ames test, mouse lymphoma assay (MLA) and in vitro micronucleus assay. The genotoxicities of silver acetate and silver nitrate were evaluated to compare the genotoxicity of nanosilver to that of ionic silver. The Ames test produced inconclusive results for all types of the silver materials due to the high toxicity of silver to the test bacteria and the lack of entry of the nanoparticles into the cells. Treatment of L5718Y cells with AgNPs and ionic silver resulted in concentration-dependent cytotoxicity, mutagenicity in the Tk gene and the induction of micronuclei from exposure to nearly every type of the silver materials. Treatment of TK6 cells with these silver materials also resulted in concentration-dependent cytotoxicity and significantly increased micronucleus frequency. With both the MLA and micronucleus assays, the smaller the AgNPs, the greater the cytotoxicity and genotoxicity. The coatings had less effect on the relative genotoxicity of AgNPs than the particle size. Loss of heterozygosity analysis of the induced Tk mutants indicated that the types of mutations induced by AgNPs were different from those of ionic silver. These results suggest that AgNPs induce cytotoxicity and genotoxicity in a size- and coating-dependent manner. Furthermore, while the MLA and in vitro micronucleus assay (in both types of cells) are useful to quantitatively measure the genotoxic potencies of AgNPs, the Ames test cannot.

Genotoxicity testing of Persicariae Rhizoma (Persicaria tinctoria H. Gross) aqueous extracts

PubMed Central

LEE, WON HO; CHOI, SEONG HUN; KANG, SU JIN; SONG, CHANG HYUN; PARK, SOO JIN; LEE, YOUNG JOON; KU, SAE KWANG

2016-01-01

Persicariae Rhizoma (PR) has been used as an anti-inflammatory and detoxification agent in Korea, and contains the biologically active dyes purple indirubin and blue indigo. Despite synthetic indigo showing genotoxic potential, thorough studies have not been carried out on the genotoxicity of PR. The potential genotoxicity of an aqueous extract of PR containing indigo (0.043%) and indirubin (0.009%) was evaluated using a standard battery of tests for safety assessment. The PR extract did not induce any genotoxic effects under the conditions of this study. The results of a reverse mutation assay in four Salmonella typhimurium strains and one Escherichia coli strain indicated that PR extract did not increase the frequency of revertant colonies in any strain, regardless of whether S9 mix was present or not. The PR extract also did not increase chromosomal aberrations in the presence or absence of S9 mix. Although slight signs of diarrhea were restrictedly detected in the mice treated with 2,000 mg/kg PR extract, no noteworthy changes in the frequency of micronucleated polychromatic erythrocytes were observed at doses ≤2,000 mg/kg in a bone marrow micronucleus test. These results indicate the potential safety of the PR extract, particularly if it is consumed in small amounts compared with the quantities used in the genotoxicity tests. PMID:27347027

Identification of consensus biomarkers for predicting non-genotoxic hepatocarcinogens

PubMed Central

Huang, Shan-Han; Tung, Chun-Wei

2017-01-01

The assessment of non-genotoxic hepatocarcinogens (NGHCs) is currently relying on two-year rodent bioassays. Toxicogenomics biomarkers provide a potential alternative method for the prioritization of NGHCs that could be useful for risk assessment. However, previous studies using inconsistently classified chemicals as the training set and a single microarray dataset concluded no consensus biomarkers. In this study, 4 consensus biomarkers of A2m, Ca3, Cxcl1, and Cyp8b1 were identified from four large-scale microarray datasets of the one-day single maximum tolerated dose and a large set of chemicals without inconsistent classifications. Machine learning techniques were subsequently applied to develop prediction models for NGHCs. The final bagging decision tree models were constructed with an average AUC performance of 0.803 for an independent test. A set of 16 chemicals with controversial classifications were reclassified according to the consensus biomarkers. The developed prediction models and identified consensus biomarkers are expected to be potential alternative methods for prioritization of NGHCs for further experimental validation. PMID:28117354

Aspect ratio has no effect on genotoxicity of multi-wall carbon nanotubes.

PubMed

Kim, Jin Sik; Lee, Kyu; Lee, Young Hee; Cho, Hyun Sun; Kim, Ki Heon; Choi, Kyung Hee; Lee, Sang Hee; Song, Kyung Seuk; Kang, Chang Soo; Yu, Il Je

2011-07-01

Carbon nanotubes (CNTs) have specific physico-chemical and electrical properties that are useful for telecommunications, medicine, materials, manufacturing processes and the environmental and energy sectors. Yet, despite their many advantages, it is also important to determine whether CNTs may represent a hazard to the environment and human health. Like asbestos, the aspect ratio (length:diameter) and metal components of CNTs are known to have an effect on the toxicity of carbon nanotubes. Thus, to evaluate the toxic potential of CNTs in relation to their aspect ratio and metal contamination, in vivo and in vitro genotoxicity tests were conducted using high-aspect-ratio (diameter: 10-15 nm, length: ~10 μm) and low-aspect-ratio multi-wall carbon nanotubes (MWCNTs, diameter: 10-15 nm, length: ~150 nm) according to OECD test guidelines 471 (bacterial reverse mutation test), 473 (in vitro chromosome aberration test), and 474 (in vivo micronuclei test) with a good laboratory practice system. To determine the treatment concentration for all the tests, a solubility and dispersive test was performed, and a 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) solution found to be more suitable than distilled water. Neither the high- nor the low-aspect-ratio MWCNTs induced any genotoxicity in a bacterial reverse mutation test (~1,000 μg/plate), in vitro chromosome aberration test (without S9: ~6.25 μg/ml, with S9: ~50 μg/ml), or in vivo micronuclei test (~50 mg/kg). However, the high-aspect-ratio MWCNTs were found to be more toxic than the low-aspect-ratio MWCNTs. Thus, while high-aspect-ratio MWCNTs do not induce direct genotoxicity or metabolic activation-mediated genotoxicity, genotoxicity could still be induced indirectly through oxidative stress or inflammation.

METHYLATED ASIII COMPOUNDS AS POTENTIAL PROXIMATE/ULTIMATE GENOTOXIC METABOLITES OF INORGANIC ARSENIC

EPA Science Inventory

METHYLATED Asm COMPOUNDS AS POTENTIAL PROXIMATE/ULTIMATE GENOTOXIC METABOLITES OF INORGANIC ARSENIC.

The methylation of inorganic arsenic has typically been viewed as a detoxification process. Genotoxicity tests have generally shown that arsenite has greater mutagenic p...

Genotoxicity of quinocetone, cyadox and olaquindox in vitro and in vivo.

PubMed

Ihsan, Awais; Wang, Xu; Zhang, Wei; Tu, Honggang; Wang, Yulian; Huang, Lingli; Iqbal, Zahid; Cheng, Guyue; Pan, Yuanhu; Liu, Zhenli; Tan, Ziqiang; Zhang, Yuanyuan; Yuan, Zonghui

2013-09-01

Quinocetone (QCT) and Cyadox (CYA) are important derivative of heterocyclic N-oxide quinoxaline (QdNO), used actively as antimicrobial feed additives in China. Here, we tested and compared the genotoxic potential of QCT and CYA with olaquindox (OLA) in Ames test, HGPRT gene mutation (HGM) test in V79 cells, unscheduled DNA synthesis (UDS) assay in human peripheral lymphocytes, chromosome aberration (CA) test, and micronucleus (MN) test in mice bone marrow. OLA was found genotoxic in all 5 assays. In Ames test, QCT produced His(+) mutants at 6.9 μg/plate in Salmonella typhimurium TA 97, at 18.2 μg/plate in TA 100, TA 1535, TA 1537, and at 50 μg/plate in TA 98. CYA produced His(+) mutants at 18.2 μg/plate in TA 97, TA 1535, and at 50 μg/plate in TA 98, TA 100 and TA 1537. QCT was found positive in HGM and UDS assay at concentrations ≥10 μg/ml while negative results were reported in CA test and MN test. Collectively, we found that OLA was more genotoxic than QCT and CYA. Genotoxicity of QCT was found at higher concentration levels in Ames test, HGM and UDS assays while CYA showed weak mutagenic potential to bacterial cells in Ames test. Copyright © 2013 Elsevier Ltd. All rights reserved.

Genotoxicity testing of cooked cured meat pigment (CCMP) and meat emulsion coagulates prepared with CCMP.

PubMed

Stevanović, M; Cadez, P; Zlender, B; Filipic, M

2000-07-01

The preformed cooked cured meat pigment (CCMP) synthesized directly from bovine red blood cells or through a hemin intermediate was found to be a viable colorant for application to comminuted pork as a nitrite substitute. However the genotoxicity of CCMP and meat emulsion coagulates prepared with CCMP has not been evaluated. Therefore the objectives of this work were to investigate genotoxicity of CCMP and the influence of CCMP addition on genotoxicity and the content of residual nitrite in model meat emulsion coagulates. Meat emulsions were prepared from white (musculus longissimus dorsi) and red (musculus quadriceps femoris) pork muscles with two different amounts of synthesized pigment CCMP. Comparatively, emulsions with fixed addition of nitrite salt and emulsions without any addition for color development were made. Genotoxicity of CCMP and meat emulsion coagulates was tested with the SOS/umu test and the Ames test. Neither CCMP nor meat emulsion coagulates prepared with CCMP or nitrite salt were genotoxic in the SOS/umu test. In the Ames test using Salmonella Typhimurium strains TA98 and TA100 samples of coagulates prepared with CCMP and with nitrite showed weak mutagenic activity in Salmonella Typhimurium strain TA100 but only in the absence of the metabolic activation, while CCMP was not mutagenic. Coagulates prepared with CCMP contained significantly less residual nitrite than coagulates prepared with nitrite salt. These results indicate that from the human health standpoint the substitution of nitrite salt with CCMP would be highly recommendable.

Considering mutagenicity and genotoxicity in the cancer mode ...

EPA Pesticide Factsheets

It is well known that genotoxicity plays a significant role in the development of tumor formation. Mutations in somatic cells can play a key role early in cancer initiation and might affect other stages of the carcinogenic process. Determination of carcinogens that operate through a genotoxic mode of action entails evaluation of the available data. One way of determining if a chemical is acting through a genotoxic mechanism is to assemble the relevant data (human, animal, in vivo, in vitro) of individual genetic end points, evaluating the data against a current acceptance criteria (study quality, methodology used etc.), and determining the weight of evidence based on both the available data as well as evaluating against other existing information such as epidemiological data, ADME information etc. This presentation will lay-out key, currently available genotoxicity information on naphthalene, styrene and ethylbenzene. These three chemicals were chosen because all three chemicals cause mouse lung tumors, in particular bronchiolar-alveolar adenomas and carcinomas. This analysis of the data will enable further understanding of the mode of action of mouse lung tumor formation and species differences, which will impact the hazard identification and use of mode of action in the risk assessment of naphthalene, styrene, and ethylbenzene.

Further analysis of Ames-negative rodent carcinogens that are only genotoxic in mammalian cells in vitro at concentrations exceeding 1 mM, including retesting of compounds of concern.

PubMed

Kirkland, David; Fowler, Paul

2010-11-01

In the analysis by Parry et al. [Parry, J. M., Parry, E., Phrakonkham, P. and Corvi, R. (2010) Analysis of published data for top concentration considerations in mammalian cell genotoxicity testing. Mutagenesis, 25, 531-538], 24 rodent carcinogens that were negative in the Ames test were identified that were only positive in mammalian cell tests at concentrations between 1 and 10 mM. These carcinogens can be subdivided into four groups as follows: (1) probable non-genotoxic (non-mutagenic) carcinogens, tumour promoters or negative for genotoxicity in vivo (n=10); (2) questionable carcinogens (n=4); (3) carcinogens with a probable genotoxic mode of action (n=5); (4) compounds where carcinogenicity or in vivo genotoxicity is unknown or unclear (n=5). It is not expected that in vitro mammalian cell tests should give positive results with Group 1 chemicals. Within Groups 2-4, five chemicals were considered a low priority because they could be detected using modified conditions because genotoxicity was associated with precipitate or pH shifts or because non-standard metabolism was required. The remaining nine chemicals were therefore considered most critical in terms of detection of genotoxic activity in mammalian cells. Daminozide was also included because it may have given positive responses between 1 and 10 mM. Many of the reported studies could have given positive results only at >1 mM because 'old' protocols were followed. These 10 chemicals have therefore been retested using modern protocols. Some were negative even up to 10 mM. Others were positive at concentrations <1 mM. Only methylolacrylamide was positive at a concentration >1 mM (2 mM = 202 μg/ml). Low-molecular weight substances may therefore require concentrations >1 mM, but further work is needed. Based on this analysis, it is concluded that the 10 mM upper limit in mammalian cell tests can be lowered without any loss of sensitivity in detecting genotoxic rodent carcinogens. A new limit of 1 mM or 500 μg/ml, whichever is the higher, is proposed.

Testing the genotoxicity of coking wastewater using Vicia faba and Hordeum vulgare bioassays.

PubMed

Dong, Yiru; Zhang, Jintun

2010-07-01

The coking wastewater induces severe environmental problems in China, however, its toxicity has not been well known. In the present study, the genotoxicity of coking wastewater was studied using Vicia faba and Hordeum vulgare root tip cytogenetic bioassays. Results show that the tested coking wastewater decreased the mitotic index, and significantly enhanced the frequencies of micronucleus, sister chromatid exchange and pycnotic cell in concentration-dependent manners. Exposure to the same concentration wastewater, the increasing ratios of above genetic injuries were higher in V. faba than that in H. vulgare. The results imply that coking wastewater is a genotoxic agent in plant cells and exposure to the wastewater in environment may pose a potential genotoxic risk to organisms. It also suggests that both bioassays can be used for testing the genotoxicity of coking wastewater, but the V. faba assay is more sensitive than H. vulgare assay during the process. Copyright (c) 2010. Published by Elsevier Inc.

The Vitotox and ToxTracker assays: A two-test combination for quick and reliable assessment of genotoxic hazards.

PubMed

Ates, Gamze; Favyts, Dorien; Hendriks, Giel; Derr, Remco; Mertens, Birgit; Verschaeve, Luc; Rogiers, Vera; Y Doktorova, Tatyana

2016-11-01

To ensure safety for humans, it is essential to characterize the genotoxic potential of new chemical entities, such as pharmaceutical and cosmetic substances. In a first tier, a battery of in vitro tests is recommended by international regulatory agencies. However, these tests suffer from inadequate specificity: compounds may be wrongly categorized as genotoxic, resulting in unnecessary, time-consuming, and expensive in vivo follow-up testing. In the last decade, novel assays (notably, reporter-based assays) have been developed in an attempt to overcome these drawbacks. Here, we have investigated the performance of two in vitro reporter-based assays, Vitotox and ToxTracker. A set of reference compounds was selected to span a variety of mechanisms of genotoxic action and applicability domains (e.g., pharmaceutical and cosmetic ingredients). Combining the performance of the two assays, we achieved 93% sensitivity and 79% specificity for prediction of gentoxicity for this set of compounds. Both assays permit quick high-throughput analysis of drug candidates, while requiring only small quantities of the test substances. Our study shows that these two assays, when combined, can be a reliable method for assessment of genotoxicity hazard. Copyright © 2016 Elsevier B.V. All rights reserved.

A novel genotoxin-specific qPCR array based on the metabolically competent human HepaRG™ cell line as a rapid and reliable tool for improved in vitro hazard assessment.

PubMed

Ates, Gamze; Mertens, Birgit; Heymans, Anja; Verschaeve, Luc; Milushev, Dimiter; Vanparys, Philippe; Roosens, Nancy H C; De Keersmaecker, Sigrid C J; Rogiers, Vera; Doktorova, Tatyana Y

2018-04-01

Although the value of the regulatory accepted batteries for in vitro genotoxicity testing is recognized, they result in a high number of false positives. This has a major impact on society and industries developing novel compounds for pharmaceutical, chemical, and consumer products, as afflicted compounds have to be (prematurely) abandoned or further tested on animals. Using the metabolically competent human HepaRG ™ cell line and toxicogenomics approaches, we have developed an upgraded, innovative, and proprietary gene classifier. This gene classifier is based on transcriptomic changes induced by 12 genotoxic and 12 non-genotoxic reference compounds tested at sub-cytotoxic concentrations, i.e., IC10 concentrations as determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The resulting gene classifier was translated into an easy-to-handle qPCR array that, as shown by pathway analysis, covers several different cellular processes related to genotoxicity. To further assess the predictivity of the tool, a set of 5 known positive and 5 known negative test compounds for genotoxicity was evaluated. In addition, 2 compounds with debatable genotoxicity data were tested to explore how the qPCR array would classify these. With an accuracy of 100%, when equivocal results were considered positive, the results showed that combining HepaRG ™ cells with a genotoxin-specific qPCR array can improve (geno)toxicological hazard assessment. In addition, the developed qPCR array was able to provide additional information on compounds for which so far debatable genotoxicity data are available. The results indicate that the new in vitro tool can improve human safety assessment of chemicals in general by basing predictions on mechanistic toxicogenomics information.

Updated recommended lists of genotoxic and non-genotoxic chemicals for assessment of the performance of new or improved genotoxicity tests.

PubMed

Kirkland, David; Kasper, Peter; Martus, Hans-Jörg; Müller, Lutz; van Benthem, Jan; Madia, Federica; Corvi, Raffaella

2016-01-01

In 2008 we published recommendations on chemicals that would be appropriate to evaluate the sensitivity and specificity of new/modified mammalian cell genotoxicity tests, in particular to avoid misleading positive results. In light of new data it is appropriate to update these lists of chemicals. An expert panel was convened and has revised the recommended chemicals to fit the following different sets of characteristics: • Group 1: chemicals that should be detected as positive in in vitro mammalian cell genotoxicity tests. Chemicals in this group are all in vivo genotoxins at one or more endpoints, either due to DNA-reactive or non DNA-reactive mechanisms. Many are known carcinogens with a mutagenic mode of action, but a sub-class of probable aneugens has been introduced. • Group 2: chemicals that should give negative results in in vitro mammalian cell genotoxicity tests. Chemicals in this group are usually negative in vivo and non-DNA-reactive. They are either non-carcinogenic or rodent carcinogens with a non-mutagenic mode of action. • Group 3: chemicals that should give negative results in in vitro mammalian cell genotoxicity tests, but have been reported to induce gene mutations in mouse lymphoma cells, chromosomal aberrations or micronuclei, often at high concentrations or at high levels of cytotoxicity. Chemicals in this group are generally negative in vivo and negative in the Ames test. They are either non-carcinogenic or rodent carcinogens with an accepted non-mutagenic mode of action. This group contains comments as to any conditions that can be identified under which misleading positive results are likely to occur. This paper, therefore, updates these three recommended lists of chemicals and describes how these should be used for any test evaluation program. Copyright © 2015 The Authors. Published by Elsevier B.V. All rights reserved.

High-Throughput In Vivo Genotoxicity Testing: An Automated Readout System for the Somatic Mutation and Recombination Test (SMART)

PubMed Central

Kwak, Jihoon; Genovesio, Auguste; Kang, Myungjoo; Hansen, Michael Adsett Edberg; Han, Sung-Jun

2015-01-01

Genotoxicity testing is an important component of toxicity assessment. As illustrated by the European registration, evaluation, authorization, and restriction of chemicals (REACH) directive, it concerns all the chemicals used in industry. The commonly used in vivo mammalian tests appear to be ill adapted to tackle the large compound sets involved, due to throughput, cost, and ethical issues. The somatic mutation and recombination test (SMART) represents a more scalable alternative, since it uses Drosophila, which develops faster and requires less infrastructure. Despite these advantages, the manual scoring of the hairs on Drosophila wings required for the SMART limits its usage. To overcome this limitation, we have developed an automated SMART readout. It consists of automated imaging, followed by an image analysis pipeline that measures individual wing genotoxicity scores. Finally, we have developed a wing score-based dose-dependency approach that can provide genotoxicity profiles. We have validated our method using 6 compounds, obtaining profiles almost identical to those obtained from manual measures, even for low-genotoxicity compounds such as urethane. The automated SMART, with its faster and more reliable readout, fulfills the need for a high-throughput in vivo test. The flexible imaging strategy we describe and the analysis tools we provide should facilitate the optimization and dissemination of our methods. PMID:25830368

Ground and Surface Water for Drinking: A Laboratory Study on Genotoxicity Using Plant Tests

PubMed Central

Feretti, Donatella; Ceretti, Elisabetta; Gustavino, Bianca; Zerbini, llaria; Zani, Claudia; Monarca, Silvano; Rizzoni, Marco

2012-01-01

Surface waters are increasingly utilized for drinking water because groundwater sources are often polluted. Several monitoring studies have detected the presence of mutagenicity in drinking water, especially from surface sources due to the reaction of natural organic matter with disinfectant. The study aimed to investigate the genotoxic potential of the products of reaction between humic substances, which are naturally present in surface water, and three disinfectants: chlorine dioxide, sodium hypochlorite and peracetic acid. Commercial humic acids dissolved in distilled water at different total organic carbon (TOC) concentrations were studied in order to simulate natural conditions of both ground water (TOC=2.5 mg/L) and surface water (TOC=7.5 mg/L). These solutions were treated with the biocides at a 1:1 molar ratio of C:disinfectant and tested for genotoxicity using the anaphase chromosomal aberration and micronucleus tests in Allium cepa, and the Vicia faba and Tradescantia micronucleus tests. The tests were carried out after different times and with different modes of exposure, and at 1:1 and 1:10 dilutions of disinfected and undisinfected humic acid solutions. A genotoxic effect was found for sodium hypochlorite in all plant tests, at both TOCs considered, while chlorine dioxide gave positive results only with the A.cepa tests. Some positive effects were also detected for PAA (A.cepa and Tradescantia). No relevant differences were found in samples with different TOC values. The significant increase in all genotoxicity end-points induced by all tested disinfectants indicates that a genotoxic potential is exerted even in the presence of organic substances at similar concentrations to those frequently present in drinking water. PMID:25170443

Electrochemical Genotoxicity Assay Based on a SOS/umu Test Using Hydrodynamic Voltammetry in a Droplet

PubMed Central

Kuramitz, Hideki; Sazawa, Kazuto; Nanayama, Yasuaki; Hata, Noriko; Taguchi, Shigeru; Sugawara, Kazuharu; Fukushima, Masami

2012-01-01

The SOS/umu genotoxicity assay evaluates the primary DNA damage caused by chemicals from the β-galactosidase activity of S. typhimurium. One of the weaknesses of the common umu test system based on spectrophotometric detection is that it is unable to measure samples containing a high concentration of colored dissolved organic matters, sediment, and suspended solids. However, umu tests with electrochemical detection techniques prove to be a better strategy because it causes less interference, enables the analysis of turbid samples and allows detection even in small volumes without loss of sensitivity. Based on this understanding, we aim to develop a new umu test system with hydrodynamic chronoamperometry using a rotating disk electrode (RDE) in a microliter droplet. PAPG when used as a substrate is not electroactive at the potential at which PAP is oxidized to p-quinone imine (PQI), so the current response of chronoamperometry resulting from the oxidation of PAP to PQI is directly proportional to the enzymatic activity of S. typhimurium. This was achieved by performing genotoxicity tests for 2-(2-furyl)-3-(5-nitro-2-furyl)-acrylamide (AF-2) and 2-aminoanthracene (2-AA) as model genotoxic compounds. The results obtained in this study indicated that the signal detection in the genotoxicity assay based on hydrodynamic voltammetry was less influenced by the presence of colored components and sediment particles in the samples when compared to the usual colorimetric signal detection. The influence caused by the presence of humic acids (HAs) and artificial sediment on the genotoxic property of selected model compounds such as 4-nitroquinoline-N-oxide (4-NQO), 3-chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone (MX), 1,8-dinitropyrene (1,8-DNP) and 1-nitropyrene (1-NP) were also investigated. The results showed that the genotoxicity of 1-NP and MX changed in the presence of 10 mg·L−1 HAs. The genotoxicity of tested chemicals with a high hydrophobicity such as 1,8-DNP and 1-NP were decreased substantially with the presence of 1 g·L−1 sediment. This was not observed in the case of genotoxins with a low log Kow value. PMID:23242275

Genotoxicity assessment of magnetic iron oxide nanoparticles with different particle sizes and surface coatings

NASA Astrophysics Data System (ADS)

Liu, Yanping; Xia, Qiyue; Liu, Ying; Zhang, Shuyang; Cheng, Feng; Zhong, Zhihui; Wang, Li; Li, Hongxia; Xiao, Kai

2014-10-01

Magnetic iron oxide nanoparticles (IONPs) have been widely used for various biomedical applications such as magnetic resonance imaging and drug delivery. However, their potential toxic effects, including genotoxicity, need to be thoroughly understood. In the present study, the genotoxicity of IONPs with different particle sizes (10, 30 nm) and surface coatings (PEG, PEI) were assessed using three standard genotoxicity assays, the Salmonella typhimurium reverse mutation assay (Ames test), the in vitro mammalian chromosome aberration test, and the in vivo micronucleus assay. In the Ames test, SMG-10 (PEG coating, 10 nm) showed a positive mutagenic response in all the five test bacterial strains with and without metabolic activation, whereas SEI-10 (PEI coating, 10 nm) showed no mutagenesis in all tester strains regardless of metabolic activation. SMG-30 (PEG coating, 30 nm) was not mutagenic in the absence of metabolic activation, and became mutagenic in the presence of metabolic activation. In the chromosomal aberration test, no increase in the incidence of chromosomal aberrations was observed for all three IONPs. In the in vivo micronucleus test, there was no evidence of increased micronuclei frequencies for all three IONPs, indicating that they were not clastogenic in vivo. Taken together, our results demonstrated that IONPs with PEG coating exhibited mutagenic activity without chromosomal and clastogenic abnormalities, and smaller IONPs (SMG-10) had stronger mutagenic potential than larger ones (SMG-30); whereas, IONPs with SEI coating (SEI-10) were not genotoxic in all three standard genotoxicity assays. This suggests that the mutagenicity of IONPs depends on their particle size and surface coating.

Genotoxicity evaluation of So-ochim-tang-gamibang (SOCG), a herbal medicine.

PubMed

Lee, Mi Young; Park, Yang-Chun; Jin, Mirim; Kim, Eunseok; Choi, Jeong June; Jung, In Chul

2018-02-02

So-ochim-tang-gamibang (SOCG) is a traditional Korean medicine frequently used for depression in the clinical field. In this study, we evaluated the potential genotoxicity of SOCG using three standard batteries of tests as part of a safety evaluation. SOCG was evaluated for potential genotoxic effects using the standard three tests recommended by the Ministry of Food and Drug Safety (MFDS) of Korea. These tests were the bacterial reverse mutation test (Ames test), in vitro mammalian chromosomal aberration test using Chinese hamster lung cells, and in vivo micronucleus test using ICR mice. The Ames test with Salmonella typhimurium strains TA98, TA100, TA1535 and TA1537 and the Escherichia coli strain WP2uvrA(pKM101) showed that SOCG did not induce gene mutations at any dose level in all of the strains. SOCG did not induce any chromosomal aberrations in the in vitro chromosomal aberration test (for both the 6 and 24 h test) and the in vivo micronucleus test. Based on the results of these tests, it was concluded that SOCG does not exhibit any genotoxic risk under the experimental conditions of this study.

Eco- and genotoxicity profiling of a rapeseed biodiesel using a battery of bioassays.

PubMed

Eck-Varanka, Bettina; Kováts, Nora; Horváth, Eszter; Ferincz, Árpád; Kakasi, Balázs; Nagy, Szabolcs Tamás; Imre, Kornélia; Paulovits, Gábor

2018-04-30

Biodiesel is considered an important renewable energy source but still there is some controversy about its environmental toxicity, especially to aquatic life. In our study, the toxicity of water soluble fraction of biodiesel was evaluated in relatively low concentrations using a battery of bioassays: Vibrio fischeri bioluminescence inhibition, Sinapis alba root growth inhibition, Daphnia magna immobilization, boar semen live/dead ratio and DNA fragmentation and Unio pictorum micronucleus test. While the S. alba test indicated nutritive (stimulating) effect of the sample, the biodiesel exerted toxic effect in the aquatic tests. D. magna was the most sensitive with EC 50 value of 0.0226%. For genotoxicity assessment, the mussel micronucleus test (MNT) was applied, detecting considerable genotoxic potential of the biodiesel sample: it elucidated micronuclei formation already at low concentration of 3.3%. Although this test has never been employed in biodiesel eco/genotoxicity assessments, it seems a promising tool, based on its appropriate sensitivity, and representativity. Copyright © 2018 Elsevier Inc. All rights reserved.

Genotoxic effects of occupational exposure to benzene in gasoline station workers

PubMed Central

SALEM, Eman; EL-GARAWANI, Islam; ALLAM, Heba; EL-AAL, Bahiga Abd; HEGAZY, Mofrih

2017-01-01

Benzene, a hazardous component of gasoline, is a genotoxic class I human carcinogen. This study evaluated the genotoxic effects of occupational exposure to benzene in gasoline stations. Genotoxicity of exposure to benzene was assessed in peripheral blood leucocytes of 62 gasoline station workers and compared with an equal numbers of matched controls using total genomic DNA fragmentation, micronucleus test and cell viability test. An ambient air samples were collected and analyzed for Monitoring of benzene, toluene, ethyl benzene and xylene (BTEX) in work environment and control areas. DNA fragmentation, micronucleus and dead cells percent were significantly higher in exposed workers than controls. Level of benzene, Toluene, Ethyl benzene and xylene in the work environment were higher than the control areas and the permissible limits. Gasoline station workers occupationally exposed to benzene are susceptible to genotoxic effects indicated by increased DNA fragmentation, higher frequency of micronucleus and decreased leukocytes viability. PMID:29070767

Genotoxic effects of occupational exposure to benzene in gasoline station workers.

PubMed

Salem, Eman; El-Garawani, Islam; Allam, Heba; El-Aal, Bahiga Abd; Hegazy, Mofrih

2018-04-07

Benzene, a hazardous component of gasoline, is a genotoxic class I human carcinogen. This study evaluated the genotoxic effects of occupational exposure to benzene in gasoline stations. Genotoxicity of exposure to benzene was assessed in peripheral blood leucocytes of 62 gasoline station workers and compared with an equal numbers of matched controls using total genomic DNA fragmentation, micronucleus test and cell viability test. An ambient air samples were collected and analyzed for Monitoring of benzene, toluene, ethyl benzene and xylene (BTEX) in work environment and control areas. DNA fragmentation, micronucleus and dead cells percent were significantly higher in exposed workers than controls. Level of benzene, Toluene, Ethyl benzene and xylene in the work environment were higher than the control areas and the permissible limits. Gasoline station workers occupationally exposed to benzene are susceptible to genotoxic effects indicated by increased DNA fragmentation, higher frequency of micronucleus and decreased leukocytes viability.

Cytotoxicity and genotoxicity of polyethylenimine and nickel chloride in red sea bream ( Pagrosomus major) fin cell line RSBF

NASA Astrophysics Data System (ADS)

Guo, Hua-Rong; Zhang, Shi-Cui

2002-12-01

A continuous marine fish cell line RSBF (i. c. Red Sea Bream Fin) was utilized to screen the cytotoxicity and genotoxicity of polyethylenimine (PEI) and nickel chloride (NiCl2) in this study on the deleterious effects of aquatic genotoxins on fish. At the 0.01 to 1 μg/ml concentration tested, PEI had acute toxicity to the treated RSBF cells (IC50=1.12, 0.92, 0.88 and 0.64 μg/ml PEI for time 0 h, 24 h, 48 h and 72 h after treatment, respectively) and markedly inhibited their proliferation in a dose-dependent manner. At the 0.001 to 5 μmol/L concentration tested, NiCl2 posed no acute toxicity but significantly stimulated their growth (107% 214% of control). Random amplified polymorphic DNA (RAPD) technique was used to detect the genotoxic effects of PEI and NiCl2 by comparing the RAPD banding patterns of the control and treated cells. RAPD analysis indicated that at the concentrations tested, PEI was more genotoxic than NiCl2 to RSBF cells; that there was a slight dose-dependent response in the genotoxic effect of PEI but not NiCl2; and that RAPD technique might provide a sensitive, non-specific genotoxic endpoint. And the potent cytotoxicity and genotoxicity of PEI on fish cells showed that we should be cautious in utilizing it as gene, vector in fish gene transfer and human gene therapy.

Environmental effects of dredging: Methods for the assessment of the genotoxic effects of environmental contaminants. Glossary and references. Technical notes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Honeycutt, M.E.; Jarvis, A.S.; McFarland, V.A.

1995-07-01

This technical note is the third in a series of three that outline and describe the principal methods that have been developed to test the potential of environmental contaminants to cause mutagenic, carcinogenic, and teratogenic effects. The first in this series (EEDP-04-24) describes methods used to discern genotoxic effects at the sub cellular level, while the second (EEDP-04-25) describes methods used to discern genotoxic effects at the cellular and organ/organism level. Recent literature citations for each topic referenced in this series of technical notes are provided in this technical note, in addition to a glossary of terms. The information inmore » these technical notes is intended to provide Corps of Engineers personnel with a working knowledge of the terminology and conceptual basis of genotoxicity testing. To develop an improved understanding of the concepts of genotoxicity, readers are encouraged to review A Primer in Genotoxicity (Jarvis, Reilly, and Lutz 1993), presented in Volume D-93-3 of the Environmental Effects of Dredging information exchange bulletin.« less

Silver nanoparticles: correlating nanoparticle size and cellular uptake with genotoxicity

PubMed Central

Butler, Kimberly S.; Peeler, David J.; Casey, Brendan J.; Dair, Benita J.; Elespuru, Rosalie K.

2015-01-01

The focus of this research was to develop a better understanding of the pertinent physico-chemical properties of silver nanoparticles (AgNPs) that affect genotoxicity, specifically how cellular uptake influences a genotoxic cell response. The genotoxicity of AgNPs was assessed for three potential mechanisms: mutagenicity, clastogenicity and DNA strand-break-based DNA damage. Mutagenicity (reverse mutation assay) was assessed in five bacterial strains of Salmonella typhimurium and Echerichia coli, including TA102 that is sensitive to oxidative DNA damage. AgNPs of all sizes tested (10, 20, 50 and 100nm), along with silver nitrate (AgNO3), were negative for mutagenicity in bacteria. No AgNPs could be identified within the bacteria cells using transmission electron microscopy (TEM), indicating these bacteria lack the ability to actively uptake AgNPs 10nm or larger. Clastogenicity (flow cytometry-based micronucleus assay) and intermediate DNA damage (DNA strand breaks as measured in the Comet assay) were assessed in two mammalian white blood cell lines: Jurkat Clone E6-1 and THP-1. It was observed that micronucleus and Comet assay end points were inversely correlated with AgNP size, with smaller NPs inducing a more genotoxic response. TEM results indicated that AgNPs were confined within intracellular vesicles of mammalian cells and did not penetrate the nucleus. The genotoxicity test results and the effect of AgNO3 controls suggest that silver ions may be the primary, and perhaps only, cause of genotoxicity. Furthermore, since AgNO3 was not mutagenic in the gram-negative bacterial Ames strains tested, the lack of bacterial uptake of the AgNPs may not be the major reason for the lack of genotoxicity observed. PMID:25964273

Way forward in case of a false positive in vitro genotoxicity result for a cosmetic substance?

PubMed

Doktorova, Tatyana Y; Ates, Gamze; Vinken, Mathieu; Vanhaecke, Tamara; Rogiers, Vera

2014-02-01

The currently used regulatory in vitro mutagenicity/genotoxicity test battery has a high sensitivity for detecting genotoxicants, but it suffers from a large number of irrelevant positive results (i.e. low specificity) thereby imposing the need for additional follow-up by in vitro and/or in vivo genotoxicity tests. This could have a major impact on the cosmetic industry in Europe, seen the imposed animal testing and marketing bans on cosmetics and their ingredients. Afflicted, but safe substances could therefore be lost. Using the example of triclosan, a cosmetic preservative, we describe here the potential applicability of a human toxicogenomics-based in vitro assay as a potential mechanistically based follow-up test for positive in vitro genotoxicity results. Triclosan shows a positive in vitro chromosomal aberration test, but is negative during in vivo follow-up tests. Toxicogenomics analysis unequivocally shows that triclosan is identified as a compound acting through non-DNA reactive mechanisms. This proof-of-principle study illustrates the potential of genome-wide transcriptomics data in combination with in vitro experimentation as a possible weight-of-evidence follow-up approach for de-risking a positive outcome in a standard mutagenicity/genotoxicity battery. As such a substantial number of cosmetic compounds wrongly identified as genotoxicants could be saved for the future. Copyright © 2013 Elsevier Ltd. All rights reserved.

Genotoxicity induced by metal oxide nanoparticles: a weight of evidence study and effect of particle surface and electronic properties.

PubMed

Golbamaki, Azadi; Golbamaki, Nazanin; Sizochenko, Natalia; Rasulev, Bakhtiyor; Leszczynski, Jerzy; Benfenati, Emilio

2018-06-09

The genetic toxicology of nanomaterials is a crucial toxicology issue and one of the least investigated topics. Substantially, the genotoxicity of metal oxide nanomaterials' data is resulting from in vitro comet assay. Current contributions to the genotoxicity data assessed by the comet assay provide a case-by-case evaluation of different types of metal oxides. The existing inconsistency in the literature regarding the genotoxicity testing data requires intelligent assessment strategies, such as weight of evidence evaluation. Two main tasks were performed in the present study. First, the genotoxicity data from comet assay for 16 noncoated metal oxide nanomaterials with different core composition were collected. An evaluation criterion was applied to establish which of these individual lines of evidence were of sufficient quality and what weight could have been given to them in inferring genotoxic results. The collected data were surveyed on (1) minimum necessary characterization points for nanomaterials and (2) principals of correct comet assay testing for nanomaterials. Second, in this study the genotoxicity effect of metal oxide nanomaterials was investigated by quantitative nanostructure-activity relationship approach. A set of quantum-chemical descriptors was developed for all investigated metal oxide nanomaterials. A classification model based on decision tree was developed for the investigated dataset. Thus, three descriptors were identified as the most responsible factors for genotoxicity effect: heat of formation, molecular weight, and surface area of the oxide cluster based on the conductor-like screening model. Conclusively, the proposed genotoxicity assessment strategy is useful to prioritize the study of the nanomaterials for further risk assessment evaluations.

The application of the micronucleus test in Chinese hamster V79 cells to detect drug-induced photogenotoxicity.

PubMed

Kersten, B; Zhang, J; Brendler-Schwaab, S Y; Kasper, P; Müller, L

1999-09-15

Recent reports on the photochemical carcinogenicity and photochemical genotoxicity of fluoroquinolone antibacterials led to an increasing awareness for the need of a standard approach to test for photochemical genotoxicity. In this study the micronucleus test using V79 cells was adapted to photogenotoxicity testing. Results of using different UVA/UVB relationships enabled us to identify a suitable irradiation regimen for the activation of different kinds of photosensitizers. Using this regimen, 8-methoxypsoralen and the fluoroquinolones lomefloxacin, grepafloxacin and Bay Y 3118 were identified to cause micronuclei and toxicity upon photochemical activation. Among the phenothiazines tested, chlorpromazine and 2-chlorophenothiazine, were positive for both endpoints, whereas triflupromazine was only slightly photoclastogenic in the presence of strong phototoxicity. Among the other potential human photosensitizers tested (oxytetracycline, doxycycline, metronidazole, emodin, hypericin, griseofulvin), only hypericin was slightly photogenotoxic. Photochemical toxicity in the absence of photochemical genotoxicity was noted for doxycycline and emodin. With the assay system described, it is possible to determine photochemical toxicity and photochemical genotoxicity concomitantly with sufficient reliability.

Cytotoxicity and Genotoxicity Assessment of Sandalwood Essential Oil in Human Breast Cell Lines MCF-7 and MCF-10A.

PubMed

Ortiz, Carmen; Morales, Luisa; Sastre, Miguel; Haskins, William E; Matta, Jaime

2016-01-01

Sandalwood essential oil (SEO) is extracted from Santalum trees. Although α-santalol, a main constituent of SEO, has been studied as a chemopreventive agent, the genotoxic activity of the whole oil in human breast cell lines is still unknown. The main objective of this study was to assess the cytotoxic and genotoxic effects of SEO in breast adenocarcinoma (MCF-7) and nontumorigenic breast epithelial (MCF-10A) cells. Proteins associated with SEO genotoxicity were identified using a proteomics approach. Commercially available, high-purity, GC/MS characterized SEO was used to perform the experiments. The main constituents reported in the oil were (Z)-α-santalol (25.34%), (Z)-nuciferol (18.34%), (E)-β-santalol (10.97%), and (E)-nuciferol (10.46%). Upon exposure to SEO (2-8 μg/mL) for 24 hours, cell proliferation was determined by the MTT assay. Alkaline and neutral comet assays were used to assess genotoxicity. SEO exposure induced single- and double-strand breaks selectively in the DNA of MCF-7 cells. Quantitative LC/MS-based proteomics allowed identification of candidate proteins involved in this response: Ku70 (p = 1.37E - 2), Ku80 (p = 5.8E - 3), EPHX1 (p = 3.3E - 3), and 14-3-3ζ (p = 4.0E - 4). These results provide the first evidence that SEO is genotoxic and capable of inducing DNA single- and double-strand breaks in MCF-7 cells.

Cytotoxicity and Genotoxicity Assessment of Sandalwood Essential Oil in Human Breast Cell Lines MCF-7 and MCF-10A

PubMed Central

Ortiz, Carmen; Morales, Luisa; Sastre, Miguel; Haskins, William E.; Matta, Jaime

2016-01-01

Sandalwood essential oil (SEO) is extracted from Santalum trees. Although α-santalol, a main constituent of SEO, has been studied as a chemopreventive agent, the genotoxic activity of the whole oil in human breast cell lines is still unknown. The main objective of this study was to assess the cytotoxic and genotoxic effects of SEO in breast adenocarcinoma (MCF-7) and nontumorigenic breast epithelial (MCF-10A) cells. Proteins associated with SEO genotoxicity were identified using a proteomics approach. Commercially available, high-purity, GC/MS characterized SEO was used to perform the experiments. The main constituents reported in the oil were (Z)-α-santalol (25.34%), (Z)-nuciferol (18.34%), (E)-β-santalol (10.97%), and (E)-nuciferol (10.46%). Upon exposure to SEO (2–8 μg/mL) for 24 hours, cell proliferation was determined by the MTT assay. Alkaline and neutral comet assays were used to assess genotoxicity. SEO exposure induced single- and double-strand breaks selectively in the DNA of MCF-7 cells. Quantitative LC/MS-based proteomics allowed identification of candidate proteins involved in this response: Ku70 (p = 1.37E − 2), Ku80 (p = 5.8E − 3), EPHX1 (p = 3.3E − 3), and 14-3-3ζ (p = 4.0E − 4). These results provide the first evidence that SEO is genotoxic and capable of inducing DNA single- and double-strand breaks in MCF-7 cells. PMID:27293457

Quantification of umu genotoxicity level of urban river water.

PubMed

Kameya, T; Nagato, T; Nakagawa, K; Yamashita, D; Kobayashi, T; Fujie, K

2011-01-01

In recent years, the request of environmental safety management for carcinogenic substances, mutagenic substances and/or reproductive toxicity substances (CMR) has increased. This study focused on clarifying the genotoxicity level of environmental water and its release source by using the umu test provided in ISO13829. Although a genotoxicity index "induction ratio (IR)" is used in ISO13829, we normalised it to make it possible to compare various environmental water quantitatively to each other as a new index "genotoxic activity (GA=(IR-1)/Dose)". Sample water was collected and concentrated to 100 times or 1,000 times by a solid phase extraction method. As the test results, it was found that GA level in actual river water varied widely from less than the determination limit of 23 [1/L] to 1,100 [1/L] by quantitative comparison, and the value was also equivalent to more than 50 times the level of tap water. The GA level of household wastewater was not so high, but the levels of treated water from wastewater treatment plant (WTP) were from 220 [1/L] to 3,200 [1/L]. Raw sewage of some WTP shows high level genotoxicity. A part of genotoxicity substances, for example 50%, could be removed by conventional wastewater treatment, but it was not enough to reduce the water environmental load of genotoxicity.

6-gingerol prevents patulin-induced genotoxicity in HepG2 cells.

PubMed

Yang, Guang; Zhong, Laifu; Jiang, Liping; Geng, Chengyan; Cao, Jun; Sun, Xiance; Liu, Xiaofang; Chen, Min; Ma, Yufang

2011-10-01

Patulin (PAT) is a mycotoxin produced by several Penicillium, Aspergillus and Byssochlamys species. Since PAT is a potent genotoxic compound, and PAT contamination is common in fruits and fruit products, the search for newer, better agents for protection against genotoxicity of PAT is required. In this study, the chemoprotective effect of 6-gingerol against PAT-induced genotoxicity in HepG2 cells was investigated. The comet assay and micronucleus test (MNT) were used to monitor genotoxic effects. To further elucidate the underlying mechanisms, the intracellular generation of reactive oxygen species (ROS) and level of reduced glutathione (GSH) were tested. In addition, the level of oxidative DNA damage was evaluated by immunocytochemical analysis of 8-hydroxydeoxyguanosine (8-OHdG). The results showed that 6-gingerol significantly reduced the DNA strand breaks and micronuclei formation caused by PAT. Moreover, 6-gingerol effectively suppressed PAT-induced intracellular ROS formation and 8-OHdG level. The GSH depletion induced by PAT in HepG2 cells was also attenuated by 6-gingerol pretreatment. These findings suggest that 6-gingerol has a strong protective ability against the genotoxicity caused by PAT, and the antioxidant activity of 6-gingerol may play an important part in attenuating the genotoxicity of PAT. Copyright © 2011 John Wiley & Sons, Ltd.

Combination of physico-chemical analysis, Allium cepa test system and Oreochromis niloticus erythrocyte based comet assay/nuclear abnormalities tests for cyto-genotoxicity assessments of treated effluents discharged from textile industries.

PubMed

Hemachandra, Chamini K; Pathiratne, Asoka

2016-09-01

Bioassays for cyto-genotoxicity assessments are generally not required in current textile industry effluent discharge management regulations. The present study applied in vivo plant and fish based toxicity tests viz. Allium cepa test system and Oreochromis niloticus erythrocyte based comet assay and nuclear abnormalities tests in combination with physico-chemical analysis for assessing potential cytotoxic/genotoxic impacts of treated textile industry effluents reaching a major river (Kelani River) in Sri Lanka. Of the treated effluents tested from two textile industries, color in the Textile industry 1 effluents occasionally and color, biochemical oxygen demand and chemical oxygen demand in the Textile industry 2 effluents frequently exceeded the specified Sri Lankan tolerance limits for discharge of industrial effluents into inland surface waters. Exposure of A. cepa bulbs to 100% and 12.5% treated effluents from both industries resulted in statistically significant root growth retardation, mito-depression, and induction of chromosomal abnormalities in root meristematic cells in comparison to the dilution water in all cases demonstrating cyto-genotoxicity associated with the treated effluents. Exposure of O. niloticus to the 100% and 12.5% effluents, resulted in erythrocytic genetic damage as shown by elevated total comet scores and induction of nuclear abnormalities confirming the genotoxicity of the treated effluents even with 1:8 dilution. The results provide strong scientific evidence for the crucial necessity of incorporating cyto-genotoxicity impact assessment tools in textile industry effluent management regulations considering human health and ecological health of the receiving water course under chronic exposure. Copyright © 2016 Elsevier Inc. All rights reserved.

The resolving power of in vitro genotoxicity assays for cigarette smoke particulate matter.

PubMed

Scott, K; Saul, J; Crooks, I; Camacho, O M; Dillon, D; Meredith, C

2013-06-01

In vitro genotoxicity assays are often used to compare tobacco smoke particulate matter (PM) from different cigarettes. The quantitative aspect of the comparisons requires appropriate statistical methods and replication levels, to support the interpretation in terms of power and significance. This paper recommends a uniform statistical analysis for the Ames test, mouse lymphoma mammalian cell mutation assay (MLA) and the in vitro micronucleus test (IVMNT); involving a hierarchical decision process with respect to slope, fixed effect and single dose comparisons. With these methods, replication levels of 5 (Ames test TA98), 4 (Ames test TA100), 10 (Ames test TA1537), 6 (MLA) and 4 (IVMNT) resolved a 30% difference in PM genotoxicity. Copyright © 2013 Elsevier Ltd. All rights reserved.

The use of dose-response data in a margin of exposure approach to carcinogenic risk assessment for genotoxic chemicals in food.

PubMed

Benford, Diane J

2016-05-01

Genotoxic substances are generally not permitted for deliberate use in food production. However, an appreciable number of known or suspected genotoxic substances occur unavoidably in food, e.g. from natural occurrence, environmental contamination and generation during cooking and processing. Over the past decade a margin of exposure (MOE) approach has increasingly been used in assessing the exposure to substances in food that are genotoxic and carcinogenic. The MOE is defined as a reference point on the dose-response curve (e.g. a benchmark dose lower confidences limit derived from a rodent carcinogenicity study) divided by the estimated human intake. A small MOE indicates a higher concern than a very large MOE. Whilst the MOE cannot be directly equated to risk, it supports prioritisation of substances for further research or for possible regulatory action, and provides a basis for communicating to the public. So far, the MOE approach has been confined to substances for which carcinogenicity data are available. In the absence of carcinogenicity data, evidence of genotoxicity is used only in hazard identification. The challenge to the genetic toxicology community is to develop approaches for characterising risk to human health based on data from genotoxicity studies. In order to achieve wide acceptance, it would be important to further address the issues that have been discussed in the context of dose-response modelling of carcinogenicity data in order to assign levels of concern to particular MOE values, and also whether it is possible to make generic conclusions on how potency in genotoxicity assays relates to carcinogenic potency. © Crown copyright 2015.

Genotoxicity of metal oxide nanomaterials: review of recent data and discussion of possible mechanisms

NASA Astrophysics Data System (ADS)

Golbamaki, Nazanin; Rasulev, Bakhtiyor; Cassano, Antonio; Marchese Robinson, Richard L.; Benfenati, Emilio; Leszczynski, Jerzy; Cronin, Mark T. D.

2015-01-01

Nanotechnology has rapidly entered into human society, revolutionized many areas, including technology, medicine and cosmetics. This progress is due to the many valuable and unique properties that nanomaterials possess. In turn, these properties might become an issue of concern when considering potentially uncontrolled release to the environment. The rapid development of new nanomaterials thus raises questions about their impact on the environment and human health. This review focuses on the potential of nanomaterials to cause genotoxicity and summarizes recent genotoxicity studies on metal oxide/silica nanomaterials. Though the number of genotoxicity studies on metal oxide/silica nanomaterials is still limited, this endpoint has recently received more attention for nanomaterials, and the number of related publications has increased. An analysis of these peer reviewed publications over nearly two decades shows that the test most employed to evaluate the genotoxicity of these nanomaterials is the comet assay, followed by micronucleus, Ames and chromosome aberration tests. Based on the data studied, we concluded that in the majority of the publications analysed in this review, the metal oxide (or silica) nanoparticles of the same core chemical composition did not show different genotoxicity study calls (i.e. positive or negative) in the same test, although some results are inconsistent and need to be confirmed by additional experiments. Where the results are conflicting, it may be due to the following reasons: (1) variation in size of the nanoparticles; (2) variations in size distribution; (3) various purities of nanomaterials; (4) variation in surface areas for nanomaterials with the same average size; (5) differences in coatings; (6) differences in crystal structures of the same types of nanomaterials; (7) differences in size of aggregates in solution/media; (8) differences in assays; (9) different concentrations of nanomaterials in assay tests. Indeed, due to the observed inconsistencies in the recent literature and the lack of adherence to appropriate, standardized test methods, reliable genotoxicity assessment of nanomaterials is still challenging.

Tungsten carbide-cobalt as a nanoparticulate reference positive control in in vitro genotoxicity assays.

PubMed

Moche, Hélène; Chevalier, Dany; Barois, Nicolas; Lorge, Elisabeth; Claude, Nancy; Nesslany, Fabrice

2014-01-01

With the increasing human exposure to nanoparticles (NP), the evaluation of their genotoxic potential is of significant importance. However, relevance for NP of the routinely used in vitro genotoxicity assays is often questioned, and a nanoparticulate reference positive control would therefore constitute an important step to a better testing of NP, ensuring that test systems are really appropriate. In this study, we investigated the possibility of using tungsten carbide-cobalt (WC-Co) NP as reference positive control in in vitro genotoxicity assays, including 2 regulatory assays, the mouse lymphoma assay and the micronucleus assay, and in the Comet assay, recommended for the toxicological evaluation of nanomedicines by the French Agency of Human Health Products (Afssaps). Through these assays, we were able to study different genetic endpoints in 2 cell types commonly used in regulatory genotoxicity assays: the L5178Y mouse lymphoma cell line and primary cultures of human lymphocytes. Our results showed that the use of WC-Co NP as positive control in in vitro genotoxicity assays was conceivable, but that different parameters have to be considered, such as cell type and treatment schedule. L5178Y mouse lymphoma cells did not provide satisfactory results in the 3 performed tests. However, human lymphocytes were more sensitive to genotoxic effects induced by WC-Co NP, particularly after a 24-h treatment in the in vitro micronucleus assay and after a 4-h treatment in the in vitro Comet assay. Under such conditions, WC-Co could be used as a nanoparticulate reference positive control in these assays.

Analysis of Aloe vera cytotoxicity and genotoxicity associated with endodontic medication and laser photobiomodulation.

PubMed

Carvalho, Nayane Chagas; Guedes, Simone Alves Garcez; Albuquerque-Júnior, Ricardo Luiz Cavalcanti; de Albuquerque, Diana Santana; de Souza Araújo, Adriano Antunes; Paranhos, Luiz Renato; Camargo, Samira Esteves Afonso; Ribeiro, Maria Amália Gonzaga

2018-01-01

This study aims to evaluate, in vitro, the effect of Aloe vera associated with endodontic medication, with or without laser photobiomodulation (FTL) irradiation in FP6 human pulp fibroblasts. The materials were divided into eight groups: CTR - control; CL - FTL alone; AA - Aloe vera with distilled water; AL - Aloe vera with distilled water and FTL; HA - calcium hydroxide P.A. with distilled water; HL - calcium hydroxide P.A. with distilled water and FTL; HAA - calcium hydroxide P.A. with Aloe vera and distilled water; HAL - calcium hydroxide P.A. with Aloe vera, distilled water, and FTL. The cytotoxicity was evaluated by MTT assay at 24, 48, and 72h and the genotoxicity by micronucleus test assay. This study was performed in triplicate. Data obtained in both tests were statistically analyzed by ANOVA and Tukey's tests (p≤0.05). Group AA presented high genotoxicity and low cytotoxicity. After 24, 48, and 72h, the group HAA significantly reduced the cell viability. Interaction with FTL showed slightly increase cell viability after 24 and 48h in groups CL and HL (p<0.001), despite the high genotoxicity in group CL and low genotoxicity in group HL. Group AL showed higher cell survival rate at 72h (p<0.05) and high genotoxicity (p<0.001). It was concluded that Aloe vera allowed higher cell viability in human pulp fibroblasts in the presence of calcium hydroxide or with FTL separately, but genotoxicity increased in these associations. Copyright © 2017 Elsevier B.V. All rights reserved.

Retrospective analysis of the mutagenicity/genotoxicity data of the cosmetic ingredients present on the Annexes of the Cosmetic EU legislation (2000-12).

PubMed

Ates, Gamze; Doktorova, Tatyana Y; Pauwels, Marleen; Rogiers, Vera

2014-03-01

To evaluate the mutagenicity/genotoxicity of cosmetic ingredients at the regulatory level, usually a battery of three in vitro tests is applied. This battery, designed to be very sensitive, produces a high number of positive results, imposing the need for in vivo follow-up testing to clear the substance under study. In Europe, the use of experimental animals has become impossible for cosmetic ingredients due to the implementation of animal testing and marketing bans. Consequently, the possibility to 'de-risk' substances with positive in vitro results disappear and potentially safe cosmetic substances will be lost for the EU market unless currently used in vitro assays can be adapted or new non-animal mutagenicity/genotoxicity studies become available. Described strategies to improve the specificity of existing in vitro assays include optimisation of the used cell type and cytotoxicity assay and lowering of the applied top concentration. A reduction of the number of tests in the battery from three to two also has been suggested. In this study, the performance of the 'standard' in vitro mutagenicity/genotoxicity testing battery is analysed for a number of cosmetic ingredients. We composed a database with toxicological information on 249 cosmetic ingredients, mainly present on the Annexes of the European cosmetic legislation. Results revealed that the in vitro mutagenicity/genotoxicity tests showed a low specificity for the cosmetic ingredients concerned, comparable to the specificity published for chemicals. Non-confirmed or 'misleading' positive results amounted up to 93% for the in vitro test batteries. The cell type and top concentrations did not have a major impact on the specificity. With respect to cytotoxicity determinations, different end points were used, potentially leading to different testing concentrations, suggesting the need for a consensus in this matter. Overall, the results of this retrospective analysis point to an urgent need of better regulatory strategies to assess the potential mutagenicity/genotoxicity of cosmetic ingredients.

Efficacy of Allium cepa test system for screening cytotoxicity and genotoxicity of industrial effluents originated from different industrial activities.

PubMed

Pathiratne, Asoka; Hemachandra, Chamini K; De Silva, Nimal

2015-12-01

Efficacy of Allium cepa test system for screening cytotoxicity and genotoxicity of treated effluents originated from four types of industrial activities (two textile industries, three rubber based industries, two common treatment plants of industrial zones, and two water treatment plants) was assessed. Physico-chemical parameters including the heavy metal/metalloid levels of the effluents varied depending on the industry profile, but most of the measured parameters in the effluents were within the specified tolerance limits of Sri Lankan environmental regulations for discharge of industrial effluents into inland surface waters. In the A. cepa test system, the undiluted effluents induced statistically significant root growth retardation, mitosis depression, and chromosomal aberrations in root meristematic cells in most cases in comparison to the dilution water and upstream water signifying effluent induced cytotoxicity and genotoxicity. Ethyl methane sulphonate (a mutagen, positive control) and all the effluents under 1:8 dilution significantly induced total chromosomal aberrations in root meristematic cells in comparison to the dilution water and upstream water indicating inadequacy of expected 1:8 dilutions in the receiving waters for curtailing genotoxic impacts. The results support the use of a practically feasible A. cepa test system for rapid screening of cytotoxicity and genotoxicity of diverse industrial effluents discharging into inland surface waters.

Fruit extract of the medicinal plant Crataegus oxyacantha exerts genotoxic and mutagenic effects in cultured cells.

PubMed

de Quadros, Ana Paula Oliveira; Mazzeo, Dania Elisa Christofoletti; Marin-Morales, Maria Aparecida; Perazzo, Fábio Ferreira; Rosa, Paulo Cesar Pires; Maistro, Edson Luis

2017-01-01

Crataegus oxyacantha, a plant of the Rosaceae family also known "English hawthorn, haw, maybush, or whitethorn," has long been used for medicinal purposes such as digestive disorders, hyperlipidemia, dyspnea, inducing diuresis, and preventing kidney stones. However, the predominant use of this plant has been to treat cardiovascular disorders. Due to a lack of studies on the genotoxicity of C. oxyacantha, this investigation was undertaken to determine whether its fruit extract exerts cytotoxic, genotoxic, or clastogenic/aneugenic effects in leukocytes and HepG2 (liver hepatocellular carcinoma) cultured human cells, or mutagenic effects in TA100 and TA98 strains of Salmonella typhimurium bacterium. Genotoxicity analysis showed that the extract produced no marked genotoxic effects at concentrations of 2.5 or 5 µg/ml in either cell type; however, at concentrations of 10 µg/ml or higher significant DNA damage was detected. The micronucleus test also demonstrated that concentrations of 10 µg/ml or higher produced clastogenic/aneugenic responses. In the Ames test, the extract induced mutagenic effects in TA98 strain of S. typhimurium with metabolic activation at all tested concentrations (2.5 to 500 µg/ml). Data indicate that, under certain experimental conditions, the fruit extract of C. oxyacantha exerts genotoxic and clastogenic/aneugenic effects in cultured human cells, and with metabolism mutagenicity occurs in bacteria cells.

Genotoxicity evaluation of Mequindox in different short-term tests.

PubMed

Ihsan, Awais; Wang, Xu; Tu, Hong-Gong; Zhang, Wei; Dai, Meng-Hong; Peng, De-Peng; Wang, Yu-Lian; Huang, Ling-Li; Chen, Dong-Mei; Mannan, Shazia; Tao, Yan-Fei; Liu, Zhen-Li; Yuan, Zong-Hui

2013-01-01

Quinoxaline-1,4-dioxides (QdNOs) are the potent heterocyclic N-oxides with interesting biological properties such as antibacterial, anticandida, antitubercular, anticancer and antiprotozoal activities. Here, we tested and compared the mequindox (MEQ) for mutagenic abilities in a battery of different short term tests according to OECD guidelines. When compared with the controls, a strong mutagenicity of MEQ and carbadox (CBX) was observed with an approximate concentration-effect relationship in Salmonella reverse mutation test, chromosome aberration test, unscheduled DNA synthesis assay and HGPRT gene mutation test, in the absence and presence of S(9)-mix. In in vivo micronucleus test, CBX produced significant increase in the proportion of micronucleus formation than MEQ in mice bone marrow cells. From these results, we can conclude that MEQ had a strong genotoxic potential to mammalian cells in vitro as well as in vivo and its mutagenicity is slightly higher than CBX. Our results, for the 1st time, discuss the genotoxic potential of MEQ. These results not only confirm the earlier findings about CBX but also extend the knowledge and awareness about the genotoxic risk of QdNO derivatives. Copyright © 2012 Elsevier Ltd. All rights reserved.

A perspective of Genes and Environment for the development of environmental mutagen research in Asia.

PubMed

Yagi, Takashi

2017-01-01

Two years have passed since the Japanese Environmental Society (JEMS) made the official journal Genes and Environment (G&E) open access. Current subjects on environmental mutagen research to further advance this field are described herein, and the roles of JEMS and G&E are discussed. Various important subjects are being investigated in current research fields such as severe environmental pollution in Asian countries; the identification of new hazardous substances and elucidation of mutation mechanisms using newly developed techniques; the development of new genotoxicity assays including in silico predictions using information technology and artificial intelligence as well as bioassays. International exchange by scientists is important for advancing these research fields through international conferences such as the 12th International Conference and 5th Asian Congress on Environmental Mutagens and the 7th International Workshop on Genotoxicity Testing that will be held in 2017. G&E provides a common platform for high quality environmental mutagen research, contributes to the dissemination of Asian environmental mutagen research, and potentiates the level of research being conducted.

Genotoxicity of lapachol evaluated by wing spot test of Drosophila melanogaster

PubMed Central

2010-01-01

This study investigated the genotoxicity of Lapachol (LAP) evaluated by wing spot test of Drosophila melanogaster in the descendants from standard (ST) and high bioactivation (HB) crosses. This assay detects the loss of heterozygosity of marker genes expressed phenotypically on the fly's wings. Drosophila has extensive genetic homology to mammals, which makes it a suitable model organism for genotoxic investigations. Three-day-old larvae from ST crosses (females flr3/TM3, Bds x males mwh/mwh), with basal levels of the cytochrome P450 and larvae of high metabolic bioactivity capacity (HB cross) (females ORR; flr3/TM3, Bds x males mwh/mwh), were used. The results showed that LAP is a promutagen, exhibiting genotoxic activity in larvae from the HB cross. In other words, an increase in the frequency of spots is exclusive of individuals with a high level of the cytochrome P450. The results also indicate that recombinogenicity is the main genotoxic event induced by LAP. PMID:21637432

Genotoxicity assessment of Pyungwi-san (PWS), a traditional herbal prescription.

PubMed

Shin, In Sik; Seo, Chang Seob; Ha, Hye Kyung; Lee, Mee Young; Huang, Dae Sun; Huh, Jung Im; Shin, Hyeun-Kyoo

2011-01-27

Pyungwi-san (PWS, Heii-san in Japanese) is a mixture of six herbs and is traditionally used in Northeast Asia (especially Korea and Japan) for the treatment of gastrointestinal disorder, such as dyspepsia and inappetance induced by gastric dilatation and gastrointestinal catarrh. Although PWS is a widely used herbal prescription in Korea and Japan, little information is available in the literature on the safety and toxicity of PWS. As part of a safety evaluation of PWS, the present study evaluated the potential genotoxicity of PWS using a standard battery of test. We prepared PWS using a water extraction method and simultaneously extracted three compounds from PWS using high performance liquid chromatography. The PWS extract that was obtained was assayed for genotoxicity using the standard three tests recommended by the Korea Food and Drug Administration. These tests included the bacterial reverse mutation test (Ames test), the chromosomal aberration test using China hamster lung cells, and the micronucleus test using ICR mice. The Ames test showed that the PWS extract did not induce an increase in the number of revertant colonies compared with vehicle control at any dose in all of tester strains. In the micronucleus test, no significant increase was observed in micronucleated polychromatic erythrocytes (MNPCEs) at any dose of PWS extract compared with vehicle control. Conversely, chromosomal aberration test showed that the PWS extract at a dosage of 4500 μg/mL induced an increase in the number of chromosomal aberrations in the 6 h group with metabolic activation compared with the vehicle control. PWS extract exhibits genotoxicity, based on the results of the chromosomal aberration test. Thus, further detailed experiments will be needed to identify the ingredient responsible for inducing this genotoxicity and to determine its mechanism. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

JaCVAM-organized international validation study of the in vivo rodent alkaline comet assay for detection of genotoxic carcinogens: II. Summary of definitive validation study results.

PubMed

Uno, Yoshifumi; Kojima, Hajime; Omori, Takashi; Corvi, Raffaella; Honma, Masamistu; Schechtman, Leonard M; Tice, Raymond R; Beevers, Carol; De Boeck, Marlies; Burlinson, Brian; Hobbs, Cheryl A; Kitamoto, Sachiko; Kraynak, Andrew R; McNamee, James; Nakagawa, Yuzuki; Pant, Kamala; Plappert-Helbig, Ulla; Priestley, Catherine; Takasawa, Hironao; Wada, Kunio; Wirnitzer, Uta; Asano, Norihide; Escobar, Patricia A; Lovell, David; Morita, Takeshi; Nakajima, Madoka; Ohno, Yasuo; Hayashi, Makoto

2015-07-01

The in vivo rodent alkaline comet assay (comet assay) is used internationally to investigate the in vivo genotoxic potential of test chemicals. This assay, however, has not previously been formally validated. The Japanese Center for the Validation of Alternative Methods (JaCVAM), with the cooperation of the U.S. NTP Interagency Center for the Evaluation of Alternative Toxicological Methods (NICEATM)/the Interagency Coordinating Committee on the Validation of Alternative Methods (ICCVAM), the European Centre for the Validation of Alternative Methods (ECVAM), and the Japanese Environmental Mutagen Society/Mammalian Mutagenesis Study Group (JEMS/MMS), organized an international validation study to evaluate the reliability and relevance of the assay for identifying genotoxic carcinogens, using liver and stomach as target organs. The ultimate goal of this exercise was to establish an Organisation for Economic Co-operation and Development (OECD) test guideline. The study protocol was optimized in the pre-validation studies, and then the definitive (4th phase) validation study was conducted in two steps. In the 1st step, assay reproducibility was confirmed among laboratories using four coded reference chemicals and the positive control ethyl methanesulfonate. In the 2nd step, the predictive capability was investigated using 40 coded chemicals with known genotoxic and carcinogenic activity (i.e., genotoxic carcinogens, genotoxic non-carcinogens, non-genotoxic carcinogens, and non-genotoxic non-carcinogens). Based on the results obtained, the in vivo comet assay is concluded to be highly capable of identifying genotoxic chemicals and therefore can serve as a reliable predictor of rodent carcinogenicity. Copyright © 2015 Elsevier B.V. All rights reserved.

Ecotoxicological and Genotoxic Evaluation of Buenos Aires City (Argentina) Hospital Wastewater

PubMed Central

Juárez, Ángela Beatriz; Dragani, Valeria; Saenz, Magalí Elizabeth; Moretton, Juan

2014-01-01

Hospital wastewater (HWW) constitutes a potential risk to the ecosystems and human health due to the presence of toxic and genotoxic chemical compounds. In the present work we investigated toxicity and genotoxicity of wastewaters from the public hospital of Buenos Aires (Argentina). The effluent from the sewage treatment plant (STP) serving around 10 million inhabitants was also evaluated. The study was carried out between April and September 2012. Toxicity and genotoxicity assessment was performed using the green algae Pseudokirchneriella subcapitata and the Allium cepa test, respectively. Toxicity assay showed that 55% of the samples were toxic to the algae (%I of growth between 23.9 and 54.8). The A. cepa test showed that 40% of the samples were genotoxic. The analysis of chromosome aberrations (CA) and micronucleus (MN) showed no significant differences between days and significant differences between months. The sample from the STP was not genotoxic to A. cepa but toxic to the algae (%I = 41%), showing that sewage treatment was not totally effective. This study highlights the need for environmental control programs and the establishment of advanced and effective effluent treatment plants in the hospitals, which are merely dumping the wastewaters in the municipal sewerage system. PMID:25214834

The development of GADD45α luciferase reporter assays in human cells for assessing the genotoxicity of environmental pollutants.

PubMed

Xin, Lili; Wang, Jianshu; Wu, Yanhu; Guo, Sifan

2015-02-01

In order to assess the potential carcinogenic and genotoxic responses induced by environmental pollutants, genotoxicity test systems based on a GADD45α promoter-driven luciferase reporter in human A549 and HepG2 cells were established. Four different types of environmental toxicants including DNA alkylating agents, precarcinogenic agents, DNA cross-linking agents and non-carcinogenic agents, and three environmental samples collected from a coke oven plant were used to evaluate the test systems. After treated with the tested agents and environmental samples for 12 h, the cell viabilities and luciferase activities of the luciferase reporter cells were determined, respectively. Methyl methanesulfonate, benzo[a]pyrene, formaldehyde and the extractable organic matter (EOM) from coke oven emissions in ambient air generally produced significant induction of relative luciferase activity in a similar dose-dependent manner in A549- and HepG2-luciferase cells. No significant increases in relative luciferase activity were observed in pyrene-treated A549- or HepG2-luciferase cells. Significant increase in relative luciferase activity was already evident after 2.5 µM benzo[a]pyrene, 5 µM formaldehyde, 0.006 µg/L bottom-EOM, 0.10 µg/L side-EOM or 0.06 µg/L top-EOM, where no cytotoxic damage was observed. Compared with the A549-luciferase cells, the tested pollutants produced higher induction of relative luciferase activity in HepG2-luciferase cells. Therefore, the new genotoxicity test systems can detect different types of genotoxic agents and low concentrations of environmental samples. The luciferase reporter cells, especially the HepG2-luciferase cells, could provide a valuable tool for rapid screening of the genotoxic damage of environmental pollutants and their complex mixtures.

Potential genotoxic effects of melted snow from an urban area revealed by the Allium cepa test.

PubMed

Blagojević, Jelena; Stamenković, Gorana; Vujosević, Mladen

2009-09-01

The presence of well-known atmospheric pollutants is regularly screened for in large towns but knowledge about the effects of mixtures of different pollutants and especially their genotoxic potential is largely missing. Since falling snow collects pollutants from the air, melted snow samples could be suitable for evaluating potential genotoxicity. For this purpose the Allium cepa anaphase-telophase test was used to analyse melted snow samples from Belgrade, the capital city of Serbia. Samples of snow were taken at two sites, characterized by differences in pollution intensity, in three successive years. At the more polluted site the analyses showed a very high degree of both toxicity and genotoxicity in the first year of the study corresponding to the effects of the known mutagen used as the positive control. At the other site the situation was much better but not without warning signals. The results showed that standard analyses for the presence of certain contaminants in the air do not give an accurate picture of the possible consequences of urban air pollution because the genotoxic potential remains hidden. The A. cepa test has been demonstrated to be very convenient for evaluation of air pollution through analyses of melted snow samples.

Strategies for setting occupational exposure limits for particles.

PubMed Central

Greim, H A; Ziegler-Skylakakis, K

1997-01-01

To set occupational exposure limits (OELs) for aerosol particles, dusts, or chemicals, one has to evaluate whether mechanistic considerations permit identification of a no observed effect level (NOEL). In the case of carcinogenic effects, this can be assumed if no genotoxicity is involved, and exposure is considered safe if it does not exceed the NOEL. If tumor induction is associated with genotoxicity, any exposure is considered to be of risk, although a NOEL may be identified in the animal or human exposure studies. This must also be assumed when no information on the carcinogenic mechanism, including genotoxicity, is available. Aerosol particles, especially fibrous dusts, which include man-made mineral fiber(s) (MMMF), present a challenge for toxicological evaluation. Many MMMF that have been investigated have induced tumors in animals and genotoxicity in vitro. Since these effects have been associated with long-thin fiber geometry and high durability in vivo, all fibers meeting such criteria are considered carcinogenic unless the opposite has been demonstrated. This approach is practicable. Investigations on fiber tumorigenicity/genotoxicity should include information on dose response, pathobiochemistry, particle clearance, and persistence of the material in the target organ. Such information will introduce quantitative aspects into the qualitative approach that has so far been used to classify fibrous dusts as carcinogens. The rationales for classifying the potential carcinogenicity of MMMF and for setting OELs used by the different European committees and regulatory agencies are described. PMID:9400750

Genotoxic effects of exposure to radiofrequency electromagnetic fields (RF-EMF) in HL-60 cells are not reproducible.

PubMed

Speit, Günter; Gminski, Richard; Tauber, Rudolf

2013-08-15

Conflicting results have been published regarding the induction of genotoxic effects by exposure to radiofrequency electromagnetic fields (RF-EMF). Various results indicating a genotoxic potential of RF-EMF were reported by the collaborative EU-funded REFLEX (Risk Evaluation of Potential Environmental Hazards From Low Energy Electromagnetic Field Exposure Using Sensitive in vitro Methods) project. There has been a long-lasting scientific debate about the reliability of the reported results and an attempt to reproduce parts of the results obtained with human fibroblasts failed. Another part of the REFLEX study was performed in Berlin with the human lymphoblastoid cell line HL-60; genotoxic effects of RF-EMF were measured by means of the comet assay and the micronucleus test. The plausibility and reliability of these results were also questioned. In order to contribute to a clarification of the biological significance of the reported findings, a repeat study was performed, involving scientists of the original study. Comet-assay experiments and micronucleus tests were performed under the same experimental conditions that had led to genotoxic effects in the REFLEX study. Here we report that the attempts to reproduce the induction of genotoxic effects by RF-EMF in HL-60 cells failed. No genotoxic effects of RF-EMF were measured in the repeat experiments. We could not find an explanation for the conflicting results. However, the negative repeat experiments suggest that the biological significance of genotoxic effects of RF-EMF reported by the REFLEX study should be re-assessed. Copyright © 2013 Elsevier B.V. All rights reserved.

Trivalent chromium: assessing the genotoxic risk of an essential trace element and widely used human and animal nutritional supplement.

PubMed

Eastmond, David A; Macgregor, James T; Slesinski, Ronald S

2008-01-01

Trivalent chromium [Cr(III)] is recognized as an essential nutrient, and is widely used as a nutritional supplement for humans and animals. Recent reports of the induction of genetic damage in cultured cells exposed to Cr(III) compounds in vitro have heightened the concern that Cr(III) compounds may exert genotoxic effects under certain conditions, raising the question of the relative benefit versus risk of dietary and feed supplementation practices. We have reviewed the literature since 1990 on genotoxic effects of Cr(III) compounds to determine whether recent findings provide a sufficient weight of evidence to modify the conclusions about the safety of this dietary supplement reached in the several comprehensive reviews conducted during the period 1990-2004. The extensive literature on genotoxic effects of Cr(III) compounds includes many instances of conflicting information, with both negative and positive findings often reported in similar test systems. Outcomes of in vitro tests conducted with Cr(III) in cultured cells are quite variable regardless of the chemical form of the chromium compound tested. The in vitro data show that Cr(III) has the potential to react with DNA and to cause DNA damage in cell culture systems, but under normal circumstances, restricted access of Cr(III) to cells in vivo limits or prevents genotoxicity in biological systems. The available in vivo evidence suggests that genotoxic effects are very unlikely to occur in humans or animals exposed to nutritional or to moderate recommended supplemental levels of Cr(III). However, excessive intake of Cr(III) supplements does not appear to be warranted at this time. Thus, like other nutrients that have exhibited genotoxic effects in vitro under high exposure conditions, nutritional benefits appear to outweigh the theoretical risk of genotoxic effects in vivo at normal or modestly elevated physiological intake levels.

Comet assay in reconstructed 3D human epidermal skin models--investigation of intra- and inter-laboratory reproducibility with coded chemicals.

PubMed

Reus, Astrid A; Reisinger, Kerstin; Downs, Thomas R; Carr, Gregory J; Zeller, Andreas; Corvi, Raffaella; Krul, Cyrille A M; Pfuhler, Stefan

2013-11-01

Reconstructed 3D human epidermal skin models are being used increasingly for safety testing of chemicals. Based on EpiDerm™ tissues, an assay was developed in which the tissues were topically exposed to test chemicals for 3h followed by cell isolation and assessment of DNA damage using the comet assay. Inter-laboratory reproducibility of the 3D skin comet assay was initially demonstrated using two model genotoxic carcinogens, methyl methane sulfonate (MMS) and 4-nitroquinoline-n-oxide, and the results showed good concordance among three different laboratories and with in vivo data. In Phase 2 of the project, intra- and inter-laboratory reproducibility was investigated with five coded compounds with different genotoxicity liability tested at three different laboratories. For the genotoxic carcinogens MMS and N-ethyl-N-nitrosourea, all laboratories reported a dose-related and statistically significant increase (P < 0.05) in DNA damage in every experiment. For the genotoxic carcinogen, 2,4-diaminotoluene, the overall result from all laboratories showed a smaller, but significant genotoxic response (P < 0.05). For cyclohexanone (CHN) (non-genotoxic in vitro and in vivo, and non-carcinogenic), an increase compared to the solvent control acetone was observed only in one laboratory. However, the response was not dose related and CHN was judged negative overall, as was p-nitrophenol (p-NP) (genotoxic in vitro but not in vivo and non-carcinogenic), which was the only compound showing clear cytotoxic effects. For p-NP, significant DNA damage generally occurred only at doses that were substantially cytotoxic (>30% cell loss), and the overall response was comparable in all laboratories despite some differences in doses tested. The results of the collaborative study for the coded compounds were generally reproducible among the laboratories involved and intra-laboratory reproducibility was also good. These data indicate that the comet assay in EpiDerm™ skin models is a promising model for the safety assessment of compounds with a dermal route of exposure.

Comet assay in reconstructed 3D human epidermal skin models—investigation of intra- and inter-laboratory reproducibility with coded chemicals

PubMed Central

Pfuhler, Stefan

2013-01-01

Reconstructed 3D human epidermal skin models are being used increasingly for safety testing of chemicals. Based on EpiDerm™ tissues, an assay was developed in which the tissues were topically exposed to test chemicals for 3h followed by cell isolation and assessment of DNA damage using the comet assay. Inter-laboratory reproducibility of the 3D skin comet assay was initially demonstrated using two model genotoxic carcinogens, methyl methane sulfonate (MMS) and 4-nitroquinoline-n-oxide, and the results showed good concordance among three different laboratories and with in vivo data. In Phase 2 of the project, intra- and inter-laboratory reproducibility was investigated with five coded compounds with different genotoxicity liability tested at three different laboratories. For the genotoxic carcinogens MMS and N-ethyl-N-nitrosourea, all laboratories reported a dose-related and statistically significant increase (P < 0.05) in DNA damage in every experiment. For the genotoxic carcinogen, 2,4-diaminotoluene, the overall result from all laboratories showed a smaller, but significant genotoxic response (P < 0.05). For cyclohexanone (CHN) (non-genotoxic in vitro and in vivo, and non-carcinogenic), an increase compared to the solvent control acetone was observed only in one laboratory. However, the response was not dose related and CHN was judged negative overall, as was p-nitrophenol (p-NP) (genotoxic in vitro but not in vivo and non-carcinogenic), which was the only compound showing clear cytotoxic effects. For p-NP, significant DNA damage generally occurred only at doses that were substantially cytotoxic (>30% cell loss), and the overall response was comparable in all laboratories despite some differences in doses tested. The results of the collaborative study for the coded compounds were generally reproducible among the laboratories involved and intra-laboratory reproducibility was also good. These data indicate that the comet assay in EpiDerm™ skin models is a promising model for the safety assessment of compounds with a dermal route of exposure. PMID:24150594

Application of the TGx‐28.65 transcriptomic biomarker to classify genotoxic and non‐genotoxic chemicals in human TK6 cells in the presence of rat liver S9

PubMed Central

Buick, Julie K.; Williams, Andrew; Swartz, Carol D.; Recio, Leslie; Li, Heng‐Hong; Fornace, Albert J.; Thomson, Errol M.; Aubrecht, Jiri

2016-01-01

In vitro transcriptional signatures that predict toxicities can facilitate chemical screening. We previously developed a transcriptomic biomarker (known as TGx‐28.65) for classifying agents as genotoxic (DNA damaging) and non‐genotoxic in human lymphoblastoid TK6 cells. Because TK6 cells do not express cytochrome P450s, we confirmed accurate classification by the biomarker in cells co‐exposed to 1% 5,6 benzoflavone/phenobarbital‐induced rat liver S9 for metabolic activation. However, chemicals may require different types of S9 for activation. Here we investigated the response of TK6 cells to higher percentages of Aroclor‐, benzoflavone/phenobarbital‐, or ethanol‐induced rat liver S9 to expand TGx‐28.65 biomarker applicability. Transcriptional profiles were derived 3 to 4 hr following a 4 hr co‐exposure of TK6 cells to test chemicals and S9. Preliminary studies established that 10% Aroclor‐ and 5% ethanol‐induced S9 alone did not induce the TGx‐28.65 biomarker genes. Seven genotoxic and two non‐genotoxic chemicals (and concurrent solvent and positive controls) were then tested with one of the S9s (selected based on cell survival and micronucleus induction). Relative survival and micronucleus frequency was assessed by flow cytometry in cells 20 hr post‐exposure. Genotoxic/non‐genotoxic chemicals were accurately classified using the different S9s. One technical replicate of cells co‐treated with dexamethasone and 10% Aroclor‐induced S9 was falsely classified as genotoxic, suggesting caution in using high S9 concentrations. Even low concentrations of genotoxic chemicals (those not causing cytotoxicity) were correctly classified, demonstrating that TGx‐28.65 is a sensitive biomarker of genotoxicity. A meta‐analysis of datasets from 13 chemicals supports that different S9s can be used in TK6 cells, without impairing classification using the TGx‐28.65 biomarker. Environ. Mol. Mutagen. 57:243–260, 2016. © 2016 Her Majesty the Queen in Right of Canada. Environmental and Molecular Mutagenesis © 2016 Environmental Mutagen Society PMID:26946220

Summary of major conclusions from the 6th International Workshop on Genotoxicity Testing (IWGT), Foz do Iguacu, Brazil

EPA Science Inventory

The paper describes major conclusions of working groups convened in the following areas: comet assay; micronucleus test in the liver and organs other than bone marrow; pig-A assay; quantitative approaches to genotoxicity risk assessment; and approaches for identifying germ cell m...

GENOTOXIC ACTIVITY OF 1-CHLOROMETHYLPYRENE IN STOMACH EPITHELIUM IN VIVO: INSENSITIVITY OF THE SCINTILLATION UDS ASSAY

EPA Science Inventory

An acknowledged weakness of current testing programs for genotoxic hazard has been the potential insensitivity of the established mouse bone ma,-row micronucleus test and rat liver UDS assays to direct-acting or short lived mutagens which may be consumed at the site of initial co...

REDUCTION OF GENOTOXICITY OF A CREOSOTE-CONTAMINATED SOIL AFTER FUNGAL TREATMENT DETERMINED BY THE TRADESCANTIA-MICRONUCLEUS TEST

EPA Science Inventory

The fungal degradation of polyaromatic hydrocarbons (PAH) in a contaminated soil from a hazarous waste site was evaluated in a pilot-scale study. As some PAH are known to be mutagens, the Tradescantia-micronucleus test (TRAD-MCN) was selected to evaluate the genotoxicity of the s...

Genotoxic and anti-genotoxic effects of esculin and its oligomer fractions against mitomycin C-induced DNA damages in mice.

PubMed

Mokdad Bzeouich, Imen; Mustapha, Nadia; Maatouk, Mouna; Ghedira, Kamel; Ghoul, Mohamed; Chekir-Ghedira, Leila

2016-12-01

Mitomycin C is one of the most effective chemotherapeutic drugs against various solid tumors. However, despite its wide spectrum of clinical benefits, this agent is capable of inducing various types of genotoxicity. In this study, we investigated the effect of esculin and its oligomer fractions (E1, E2 and E3) against mitomycin C induced genotoxicity in liver and kidney cells isolated from Balb/C mice using the comet assay. Esculin and its oligomer fractions were not genotoxic at the tested doses (20 mg/kg and 40 mg/kg b.w). A significant decrease in DNA damages was observed, suggesting a protective role of esculin and its oligomer fractions against the genotoxicity induced by mitomycin C on liver and kidney cells. Moreover, esculin and its oligomer fractions did not induce an increase of malondialdehyde levels. Copyright © 2016 Elsevier Inc. All rights reserved.

Evaluation of the in vivo genotoxicity of Allura Red AC (Food Red No. 40).

PubMed

Honma, Masamitsu

2015-10-01

Allura Red AC (Food Red No. 40) is a red azo dye that is used for food coloring in beverage and confectionary products. However, its genotoxic properties remain controversial. To clarify the in vivo genotoxicity, we treated mice with Allura Red AC and investigated the induction of DNA damage (liver, glandular stomach), clastogenicity/anuegenicity (bone marrow), and mutagenicity (liver, glandular stomach) using Comet assays, micronucleus tests, and transgenic gene mutation assays, respectively. All studies were conducted in accordance with the Organization for Economic Co-operation and Development (OECD) guideline. Although Allura Red AC was administered up to the maximum doses recommended by the OECD guideline, no genotoxic effect was observed in any of the genotoxic endpoints. These data clearly show no evidence of in vivo genotoxic potential of Allura Red AC administered up to the maximum doses in mice. Copyright © 2015 Elsevier Ltd. All rights reserved.

The comet assay for the evaluation of genotoxic potential of landfill leachate.

PubMed

Widziewicz, Kamila; Kalka, Joanna; Skonieczna, Magdalena; Madej, Paweł

2012-01-01

Genotoxic assessment of landfill leachate before and after biological treatment was conducted with two human cell lines (Me45 and NHDF) and Daphnia magna somatic cells. The alkali version of comet assay was used to examine genotoxicity of leachate by DNA strand breaks analysis and its repair dynamics. The leachate samples were collected from Zabrze landfill, situated in the Upper Silesian Industrial District, Poland. Statistically significant differences (Kruskal-Wallice ANOVA rank model) were observed between DNA strand breaks in cells incubated with leachate before and after treatment (P < 0.001). Nonparametric Friedman ANOVA confirmed time-reliable and concentration-reliable cells response to leachate concentration. Examinations of chemical properties showed a marked decrease in leachate parameters after treatment which correlate to reduced genotoxicity towards tested cells. Obtained results demonstrate that biological cotreatment of leachate together with municipal wastewater is an efficient method for its genotoxic potential reduction; however, treated leachate still possessed genotoxic character.

The Comet Assay for the Evaluation of Genotoxic Potential of Landfill Leachate

PubMed Central

Widziewicz, Kamila; Kalka, Joanna; Skonieczna, Magdalena; Madej, Paweł

2012-01-01

Genotoxic assessment of landfill leachate before and after biological treatment was conducted with two human cell lines (Me45 and NHDF) and Daphnia magna somatic cells. The alkali version of comet assay was used to examine genotoxicity of leachate by DNA strand breaks analysis and its repair dynamics. The leachate samples were collected from Zabrze landfill, situated in the Upper Silesian Industrial District, Poland. Statistically significant differences (Kruskal-Wallice ANOVA rank model) were observed between DNA strand breaks in cells incubated with leachate before and after treatment (P < 0.001). Nonparametric Friedman ANOVA confirmed time-reliable and concentration-reliable cells response to leachate concentration. Examinations of chemical properties showed a marked decrease in leachate parameters after treatment which correlate to reduced genotoxicity towards tested cells. Obtained results demonstrate that biological cotreatment of leachate together with municipal wastewater is an efficient method for its genotoxic potential reduction; however, treated leachate still possessed genotoxic character. PMID:22666120

Genotoxicity risk assessment of diversely substituted quinolines using the SOS chromotest.

PubMed

Duran, Leidy Tatiana Díaz; Rincón, Nathalia Olivar; Galvis, Carlos Eduardo Puerto; Kouznetsov, Vladimir V; Lorenzo, Jorge Luis Fuentes

2015-03-01

Quinolines are aromatic nitrogen compounds with wide therapeutic potential to treat parasitic and microbial diseases. In this study, the genotoxicity of quinoline, 4-methylquinoline, 4-nitroquinoline-1-oxide (4-NQO), and diversely functionalized quinoline derivatives and the influence of the substituents (functional groups and/or atoms) on their genotoxicity were tested using the SOS chromotest. Quinoline derivatives that induce genotoxicity by the formation of an enamine epoxide structure did not induce the SOS response in Escherichia coli PQ37 cells, with the exception of 4-methylquinoline that was weakly genotoxic. The chemical nature of the substitution (C-5 to C-8: hydroxyl, nitro, methyl, isopropyl, chlorine, fluorine, and iodine atoms; C-2: phenyl and 3,4-methylenedioxyphenyl rings) of quinoline skeleton did not significantly modify compound genotoxicities; however, C-2 substitution with α-, β-, or γ-pyridinyl groups removed 4-methylquinoline genotoxicity. On the other hand, 4-NQO derivatives whose genotoxic mechanism involves reduction of the C-4 nitro group were strong inducers of the SOS response. Methyl and nitrophenyl substituents at C-2 of 4-NQO core affected the genotoxic potency of this molecule. The relevance of these results is discussed in relation to the potential use of the substituted quinolines. The work showed the sensitivity of SOS chromotest for studying structure-genotoxicity relationships and bioassay-guided quinoline synthesis. © 2013 Wiley Periodicals, Inc.

Anti-genotoxicity of trans-anethole and eugenol in mice.

PubMed

Abraham, S K

2001-05-01

The naturally occurring flavouring agents trans-anethole and eugenol were evaluated for antigenotoxic effects in mice. The test doses of trans-anethole (40-400 mg/kg body weight) and eugenol (50-500 mg/kg weight) were administered by gavage 2 and 20 h before the genotoxins were injected intraperitoneally. Anti-genotoxic effects were assessed in the mouse bone marrow micronucleus test. Pretreatment with trans-anethole and eugenol led to significant antigenotoxic effects against cyclophosphamide (CPH), procarbazine (PCB), N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) and urethane (URE). In addition, trans-anethole inhibited the genotoxicity of ethyl methane sulfonate (EMS). Both trans-anethole and eugenol exerted dose-related antigenotoxic effects against PCB and URE. There was no significant increase in genotoxicity when trans-anethole (40-400 mg/kg body weight) and eugenol (50-500 mg/kg body weight) were administered alone.

Plant genotoxicity: a molecular cytogenetic approach in plant bioassays.

PubMed

Maluszynska, Jolanta; Juchimiuk, Jolanta

2005-06-01

It is important for the prevention of DNA changes caused by environment to understand the biological consequences of DNA damages and their molecular modes of action that lead to repair or alterations of the genetic material. Numerous genotoxicity assay systems have been developed to identify DNA reactive compounds. The available data show that plant bioassays are important tests in the detection of genotoxic contamination in the environment and the establishment of controlling systems. Plant system can detect a wide range of genetic damage, including gene mutations and chromosome aberrations. Recently introduced molecular cytogenetic methods allow analysis of genotoxicity, both at the chromosomal and DNA level. FISH gives a new possibility of the detection and analysis of chromosomal rearrangements in a great detail. DNA fragmentation can be estimated using the TUNEL test and the single cell gel electrophoresis (Comet assay).

Toxicological assessment of Anionic Methacrylate Copolymer: I. Characterization, bioavailability and genotoxicity.

PubMed

Eisele, Johanna; Haynes, Geoff; Kreuzer, Knut; Hall, Caroline

2016-12-01

Anionic Methacrylate Copolymer (AMC) is a fully polymerized copolymer used in the pharmaceutical industry as an enteric/delayed-release coating to permit the pH-dependent release of active ingredients in the gastrointestinal tract from oral dosage forms. This function is of potential use for food supplements. Oral administration of radiolabeled copolymer to rats resulted in the detection of chemically unchanged copolymer in the feces, with negligible absorption (<0.1%). AMC is therefore determined not to be bioavailable. Within a genotoxicity test battery AMC did not show any evidence of genotoxicity in bacteria and mammalian cells. Furthermore, no genotoxic effects occurred in vivo within a micronucleus test. There would therefore appear to be no safety concerns under intended conditions of oral use for the discussed toxicological endpoints. Copyright © 2016 Elsevier Inc. All rights reserved.

Environmental genotoxicity evaluation using cytogenetic end points in wild rodents.

PubMed Central

de Souza Bueno, A M; de Bragança Pereira, C A; Rabello-Gay, M N

2000-01-01

We analyzed cytogenetic end points in three populations of two species of wild rodents--Akodon montensis and Oryzomys nigripes--living in an industrial, an agricultural, and a preservation area at the Itajaí Valley, state of Santa Catarina, Brazil. Our purpose was to evaluate the performance of the following end points in the establishment of a genotoxic profile of each area: the polychromatic/normochromatic cell ratio; the mitotic index; the frequency of micronucleated cells both in the bone marrow and peripheral blood; and the frequency of cells with chromosome aberrations in the bone marrow. Preparations were obtained using conventional cytogenetic techniques. The results showed a) the role of the end points used as biomarkers in the early detection of genotoxic agents and in the identification of species and populations at higher risk; b) the difference in sensitivity of the species selected as bioindicators in relation to the cytogenetic end points analyzed; c) the need to use at least two sympatric species to detect the presence of genotoxins in each locality; and d) the need to use several end points when trying to establish a genotoxic profile of an area. PMID:11133397

Three-Dimensional, Transgenic Cell Models to Quantify Space Genotoxic Effects

NASA Technical Reports Server (NTRS)

Gonda, S. R.; Sognier, M. A.; Wu, H.; Pingerelli, P. L.; Glickman, B. W.; Dawson, David L. (Technical Monitor)

1999-01-01

The space environment contains radiation and chemical agents known to be mutagenic and carcinogenic to humans. Additionally, microgravity is a complicating factor that may modify or synergize induced genotoxic effects. Most in vitro models fail to use human cells (making risk extrapolation to humans more difficult), overlook the dynamic effect of tissue intercellular interactions on genotoxic damage, and lack the sensitivity required to measure low-dose effects. Currently a need exists for a model test system that simulates cellular interactions present in tissue, and can be used to quantify genotoxic damage induced by low levels of radiation and chemicals, and extrapolate assessed risk to humans. A state-of-the-art, three-dimensional, multicellular tissue equivalent cell culture model will be presented. It consists of mammalian cells genetically engineered to contain multiple copies of defined target genes for genotoxic assessment,. NASA-designed bioreactors were used to coculture mammalian cells into spheroids, The cells used were human mammary epithelial cells (H184135) and Stratagene's (Austin, Texas) Big Blue(TM) Rat 2 lambda fibroblasts. The fibroblasts were genetically engineered to contain -a high-density target gene for mutagenesis (60 copies of lacl/LacZ per cell). Tissue equivalent spheroids were routinely produced by inoculation of 2 to 7 X 10(exp 5) fibroblasts with Cytodex 3 beads (150 micrometers in diameter). at a 20:1 cell:bead ratio, into 50-ml HARV bioreactors (Synthecon, Inc.). Fibroblasts were cultured for 5 days, an equivalent number of epithelial cells added, and the fibroblast/epithelial cell coculture continued for 21 days. Three-dimensional spheroids with diameters ranging from 400 to 600 micrometers were obtained. Histological and immunohistochemical Characterization revealed i) both cell types present in the spheroids, with fibroblasts located primarily in the center, surrounded by epithelial cells; ii) synthesis of extracellular matrix; and iii,, mitotic cells located throughout the spheroids. Spheroidal integrity and cell viability were retained for the 30-day test period after removal of spheroids from the bioreactor. Potential utility of this three-dimensional, transgenic model for genotoxicity was initially assessed by exposure of spheroids to 0-2 Gy neon at dose rates of 0.3 to 1.5 Gy/min (National Institute of Radiological Sciences, Chiba, Japan). Quantification of mutation at the lacl gene revealed a linear dose response for mutation induction. Limited sequencing analysis of mutant clones revealed higher frequencies of deletions and multiple base sequence changes with increasing dose. These results suggest that our three-dimensional, transgenic model is applicable to a wide variety of studies involving the quantification, identification, and characterization of genotoxicity incurred in space and on Earth. This model uniquely allows investigation of the interaction of relevant factors, namely cell-to-cell interactions and the mechanistic interaction of microgravity with radiation insults and DNA repair. Using this three-dimensional model will allow us to obtain dual genotoxic information (i.e., mutation rate plus chromosome aberration data) from the same system so that one endpoint can be used to reference the other, thereby increasing the fidelity of the data set. Moreover, the tissue-equivalent nature of the three-dimensional model provides high confidence for relevance of risk assessment, i.e., the establishment of quality factors directly applicable to the microgravity environment.

Detection of genotoxic effects of drinking water disinfection by-products using Vicia faba bioassay.

PubMed

Hu, Yu; Tan, Li; Zhang, Shao-Hui; Zuo, Yu-Ting; Han, Xue; Liu, Na; Lu, Wen-Qing; Liu, Ai-Lin

2017-01-01

Plant-based bioassays have gained wide use among the toxicological and/or ecotoxicological assessment procedures because of their simplicity, sensitivity, low cost, and reliability. The present study describes the use of Vicia faba (V. faba) micronucleus (MN) test and V. faba comet assay in the evaluation of the genotoxic potential of disinfection by-products (DBPs) commonly found in chlorine-disinfected drinking water. Five haloacetic acids and three halogenated acetonitriles were chosen as representatives of DBPs in this study because they are of potentially great public health risk. Results of the MN test indicated that monochloroacetic acid (MCA), monobromoacetic acid (MBA), dichloroacetic acid (DCA), dibromoacetic acid (DBA), trichloroacetic acid (TCA), and trichloroacetonitrile (TCAN) caused a statistically significant increase in MN frequency in V. faba root tip cells. However, no genotoxic response was observed for dichloroacetonitrile (DCAN) and dibromoacetonitrile (DBAN). Results of the comet assay showed that all tested DBPs induced a statistically significant increase in genomic DNA damage to V. faba root tip cells. On considering the capacity to detect genomic damage of a different nature, we suggest that a combination of V. faba MN test and V. faba comet assay is a useful tool for the detection of genotoxic effects of DBPs. It is worthy of assessing the feasibility of using V. faba comet assay combined with V. faba MN test to screen for the genotoxic activity of chlorinated drinking water in future work.

Genotoxicity assessment of nanomaterials: recommendations on best practices, assays and methods.

PubMed

Elespuru, Rosalie; Pfuhler, Stefan; Aardema, Marilyn; Chen, Tao; Doak, Shareen H; Doherty, Ann; Farabaugh, Christopher S; Kenny, Julia; Manjanatha, Mugimane; Mahadevan, Brinda; Moore, Martha M; Ouédraogo, Gladys; Stankowski, Leon F; Tanir, Jennifer Y

2018-04-26

Nanomaterials (NMs) present unique challenges in safety evaluation. An international working group, the Genetic Toxicology Technical Committee of the International Life Sciences Institute's Health and Environmental Sciences Institute, has addressed issues related to the genotoxicity assessment of NMs. A critical review of published data has been followed by recommendations on methods alterations and best practices for the standard genotoxicity assays: bacterial reverse mutation (Ames); in vitro mammalian assays for mutations, chromosomal aberrations, micronucleus induction, or DNA strand breaks (comet); and in vivo assays for genetic damage (micronucleus, comet and transgenic mutation assays). The analysis found a great diversity of tests and systems used for in vitro assays; many did not meet criteria for a valid test, and/or did not use validated cells and methods in the Organization for Economic Co-operation and Development Test Guidelines, and so these results could not be interpreted. In vivo assays were less common but better performed. It was not possible to develop conclusions on test system agreement, NM activity, or mechanism of action. However, the limited responses observed for most NMs were consistent with indirect genotoxic effects, rather than direct interaction of NMs with DNA. We propose a revised genotoxicity test battery for NMs that includes in vitro mammalian cell mutagenicity and clastogenicity assessments; in vivo assessments would be added only if warranted by information on specific organ exposure or sequestration of NMs. The bacterial assays are generally uninformative for NMs due to limited particle uptake and possible lack of mechanistic relevance, and are thus omitted in our recommended test battery for NM assessment. Recommendations include NM characterization in the test medium, verification of uptake into target cells, and limited assay-specific methods alterations to avoid interference with uptake or endpoint analysis. These recommendations are summarized in a Roadmap guideline for testing.

Uranium mining wastes: The use of the Fish Embryo Acute Toxicity Test (FET) test to evaluate toxicity and risk of environmental discharge.

PubMed

Lourenço, J; Marques, S; Carvalho, F P; Oliveira, J; Malta, M; Santos, M; Gonçalves, F; Pereira, R; Mendo, S

2017-12-15

Active and abandoned uranium mining sites often create environmentally problematic situations, since they cause the contamination of all environmental matrices (air, soil and water) with stable metals and radionuclides. Due to their cytotoxic, genotoxic and teratogenic properties, the exposure to these contaminants may cause several harmful effects in living organisms. The Fish Embryo Acute Toxicity Test (FET) test was employed to evaluate the genotoxic and teratogenic potential of mine liquid effluents and sludge elutriates from a deactivated uranium mine. The aims were: a) to determine the risk of discharge of such wastes in the environment; b) the effectiveness of the chemical treatment applied to the uranium mine water, which is a standard procedure generally applied to liquid effluents from uranium mines and mills, to reduce its toxicological potential; c) the suitability of the FET test for the evaluation the toxicity of such wastes and the added value of including the evaluation of genotoxicity. Results showed that through the FET test it was possible to determine that both elutriates and effluents are genotoxic and also that the mine effluent is teratogenic at low concentrations. Additionally, liquid effluents and sludge elutriates affect other parameters namely, growth and hatching and that water pH alone played an important role in the hatching process. The inclusion of genotoxicity evaluation in the FET test was crucial to prevent the underestimation of the risks posed by some of the tested effluents/elutriates. Finally, it was possible to conclude that care should be taken when using benchmark values calculated for specific stressors to evaluate the risk posed by uranium mining wastes to freshwater ecosystems, due to their chemical complexity. Copyright © 2017 Elsevier B.V. All rights reserved.

Assessing genotoxicity of diuron on Drosophila melanogaster by the wing-spot test and the wing imaginal disk comet assay.

PubMed

Peraza-Vega, Ricardo I; Castañeda-Sortibrán, América N; Valverde, Mahara; Rojas, Emilio; Rodríguez-Arnaiz, Rosario

2017-05-01

The aim of this study was to evaluate the genotoxicity of the herbicide diuron in the wing-spot test and a novel wing imaginal disk comet assay in Drosophila melanogaster. The wing-spot test was performed with standard (ST) and high-bioactivation (HB) crosses after providing chronic 48 h treatment to third instar larvae. A positive dose-response effect was observed in both crosses, but statistically reduced spot frequencies were registered for the HB cross compared with the ST. This latter finding suggests that metabolism differences play an important role in the genotoxic effect of diuron. To verify diuron's ability to produce DNA damage, a wing imaginal disk comet assay was performed after providing 24 h diuron treatment to ST and HB third instar larvae. DNA damage induced by the herbicide had a significantly positive dose-response effect even at very low concentrations in both strains. However, as noted for the wing-spot test, a significant difference between strains was not observed that could be related to the duration of exposure between both assays. A positive correlation between the comet assay and the wing-spot test was found with regard to diuron genotoxicity.

Assessment of Genotoxic Potential of Hridayarnava Rasa (A Herbo-Mineralo-Metallic Ayurvedic Formulation) Using Chromosomal Aberration and Sperm Abnormality Assays

PubMed Central

Jagtap, Chandrashekhar Y.; Chaudhari, Swapnil Y.; Thakkar, Jalaram H.; Galib, R.; Prajapati, P. K.

2014-01-01

Objectives: Herbo-mineral formulations are being successfully used in therapeutics since centuries. But recently, they came under the scanner for their metallic contents especially the presence of heavy metals. Hence it is the need of the hour to assess and establish the safety of these formulations through toxicity studies. In line with the various toxicity studies that are being carried out, Government of India expressed the need for conducting genotoxicity studies of different metal- or mineral-based drugs. Till date very few Ayurvedic herbo-mineral formulations have been studied for their genotoxic potential. The present study is aimed to evaluate the genotoxic potential of Hridayarnava Rasa. Materials and Methods: It was prepared as per classical guidelines and administered to Swiss albino mice for 14 consecutive days. Chromosomal aberration and sperm abnormality assay were done to evaluate the genotoxic potential of the test drugs. Cyclophosphamide (CP) was taken as positive group and results were compared. Results: All treated groups exhibited significant body weight gain in comparison to CP group. Results revealed no structural deformity in the above parameters in comparison to the CP-treated group. Conclusion: Reported data showed that both tested samples of Hridayarnava Rasa does not possess genotoxic potential under the experimental conditions and can be safely used. PMID:25948961

A comparison of genotoxicity change in reclaimed wastewater from different disinfection processes.

PubMed

Chai, Qiwan; Hu, Allen; Qian, Yukun; Ao, Xiuwei; Liu, Wenjun; Yang, Hongwei; Xie, Yuefeng F

2018-01-01

Effluents before disinfection from four wastewater reclamation plants were treated with chlorine (Cl 2 ), ozone (O 3 ), chlorine dioxide (ClO 2 ), medium-pressure ultraviolet (MPUV) and four different combinations of the above, to evaluate the effect of disinfection processes on the genotoxicity removal by the SOS/umu test. Results showed that the genotoxicity increased after MPUV irradiation (10-100 mJ/cm 2 ), but declined when adopting other disinfection processes. The effectiveness of genotoxicity reduction by five chemical disinfectants was identified as: O 3  > pre-ozonation with Cl 2  ≈ ClO 2  > combination of ClO 2 and Cl 2  > Cl 2 . The sequential combination of MPUV, Cl 2 and O 3 reduced the genotoxicity to a level similar to the source water. The influence of differential disinfection process varied on iodinated wastewater, which is closely related to the competitive reactions between disinfectants, iodine and dissolved organic matters. The removal of genotoxic pollutants and the formation of genotoxic disinfection by-products are the two major factors that lead to the change in genotoxicity during disinfection. Copyright © 2017 Elsevier Ltd. All rights reserved.

Identification of transcriptional networks involved in peroxisome proliferator chemical-induced hepatocyte proliferation

EPA Science Inventory

Peroxisome proliferator chemical (PPC) exposure leads to increases in rodent liver tumors through a non-genotoxic mode of action (MOA). The PPC MOA includes increased oxidative stress, hepatocyte proliferation and decreased apoptosis. We investigated the putative genetic regulato...

Opportunities to integrate new approaches in genetic toxicology: an ILSI-HESI workshop report.

PubMed

Zeiger, Errol; Gollapudi, Bhaskar; Aardema, Marilyn J; Auerbach, Scott; Boverhof, Darrell; Custer, Laura; Dedon, Peter; Honma, Masamitsu; Ishida, Seiichi; Kasinski, Andrea L; Kim, James H; Manjanatha, Mugimane G; Marlowe, Jennifer; Pfuhler, Stefan; Pogribny, Igor; Slikker, William; Stankowski, Leon F; Tanir, Jennifer Y; Tice, Raymond; van Benthem, Jan; White, Paul; Witt, Kristine L; Thybaud, Véronique

2015-04-01

Genetic toxicity tests currently used to identify and characterize potential human mutagens and carcinogens rely on measurements of primary DNA damage, gene mutation, and chromosome damage in vitro and in rodents. The International Life Sciences Institute Health and Environmental Sciences Institute (ILSI-HESI) Committee on the Relevance and Follow-up of Positive Results in In Vitro Genetic Toxicity Testing held an April 2012 Workshop in Washington, DC, to consider the impact of new understanding of biology and new technologies on the identification and characterization of genotoxic substances, and to identify new approaches to inform more accurate human risk assessment for genetic and carcinogenic effects. Workshop organizers and speakers were from industry, academe, and government. The Workshop focused on biological effects and technologies that would potentially yield the most useful information for evaluating human risk of genetic damage. Also addressed was the impact that improved understanding of biology and availability of new techniques might have on genetic toxicology practices. Workshop topics included (1) alternative experimental models to improve genetic toxicity testing, (2) Biomarkers of epigenetic changes and their applicability to genetic toxicology, and (3) new technologies and approaches. The ability of these new tests and technologies to be developed into tests to identify and characterize genotoxic agents; to serve as a bridge between in vitro and in vivo rodent, or preferably human, data; or to be used to provide dose response information for quantitative risk assessment was also addressed. A summary of the workshop and links to the scientific presentations are provided. © 2014 Wiley Periodicals, Inc.

Evaluation of genetic damage induced by glyphosate isopropylamine salt using Tradescantia bioassays.

PubMed

Alvarez-Moya, Carlos; Silva, Mónica Reynoso; Arámbula, Alma Rosa Villalobos; Sandoval, Alfonso Islas; Vasquez, Hugo Castañeda; González Montes, Rosa María

2011-01-01

Glyphosate is noted for being non-toxic in fishes, birds and mammals (including humans). Nevertheless, the degree of genotoxicity is seriously controversial. In this work, various concentrations of a glyphosate isopropylamine salt were tested using two methods of genotoxicity assaying, viz., the pink mutation assay with Tradescantia (4430) and the comet assay with nuclei from staminal cells of the same plant. Staminal nuclei were studied in two different forms, namely nuclei from exposed plants, and nuclei exposed directly. Using the pink mutation assay, isopropylamine induced a total or partial loss of color in staminal cells, a fundamental criterion utilized in this test. Consequently, its use is not recommended when studying genotoxicity with agents that produce pallid staminal cells. The comet assay system detected statistically significant (p < 0.01) genotoxic activity by isopropylamine, when compared to the negative control in both the nuclei of treated plants and directly treated nuclei, but only the treated nuclei showed a dose-dependent increase. Average migration in the nuclei of treated plants increased, when compared to that in treated nuclei. This was probably due, either to the permanence of isopropylamine in inflorescences, or to the presence of secondary metabolites. In conclusion, isopropylamine possesses strong genotoxic activity, but its detection can vary depending on the test systems used.

Evaluation of genetic damage induced by glyphosate isopropylamine salt using Tradescantia bioassays

PubMed Central

Alvarez-Moya, Carlos; Silva, Mónica Reynoso; Arámbula, Alma Rosa Villalobos; Sandoval, Alfonso Islas; Vasquez, Hugo Castañeda; González Montes, Rosa María

2011-01-01

Glyphosate is noted for being non-toxic in fishes, birds and mammals (including humans). Nevertheless, the degree of genotoxicity is seriously controversial. In this work, various concentrations of a glyphosate isopropylamine salt were tested using two methods of genotoxicity assaying, viz., the pink mutation assay with Tradescantia (4430) and the comet assay with nuclei from staminal cells of the same plant. Staminal nuclei were studied in two different forms, namely nuclei from exposed plants, and nuclei exposed directly. Using the pink mutation assay, isopropylamine induced a total or partial loss of color in staminal cells, a fundamental criterion utilized in this test. Consequently, its use is not recommended when studying genotoxicity with agents that produce pallid staminal cells. The comet assay system detected statistically significant (p < 0.01) genotoxic activity by isopropylamine, when compared to the negative control in both the nuclei of treated plants and directly treated nuclei, but only the treated nuclei showed a dose-dependent increase. Average migration in the nuclei of treated plants increased, when compared to that in treated nuclei. This was probably due, either to the permanence of isopropylamine in inflorescences, or to the presence of secondary metabolites. In conclusion, isopropylamine possesses strong genotoxic activity, but its detection can vary depending on the test systems used. PMID:21637555

GENOTOXICITY RISK ASSESSMENT: A PROPOSED CLASSIFICATION STRATEGY

EPA Science Inventory

Recent advances in genetic toxicity (mutagenicity) testing methods and in approaches to performing risk assessment are prompting a renewed effort to harmonize genotoxicity risk assessment across the world. The US Environmental Protection Agency (EPA) first published Guidelines fo...

The use of ex vivo human skin tissue for genotoxicity testing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Reus, Astrid A.; Usta, Mustafa; Krul, Cyrille A.M., E-mail: cyrille.krul@tno.nl

2012-06-01

As a result of the chemical legislation concerning the registration, evaluation, authorization and restriction of chemicals (REACH), and the Seventh Amendment to the Cosmetics Directive, which prohibits animal testing in Europe for cosmetics, alternative methods for safety evaluation of chemicals are urgently needed. Current in vitro genotoxicity assays are not sufficiently predictive for the in vivo situation, resulting in an unacceptably high number of misleading positives. For many chemicals and ingredients of personal care products the skin is the first site of contact, but there are no in vitro genotoxicity assays available in the skin for additional evaluation of positivemore » or equivocal responses observed in regulatory in vitro genotoxicity assays. In the present study ex vivo human skin tissue obtained from surgery was used for genotoxicity evaluation of chemicals by using the comet assay. Fresh ex vivo human skin tissue was cultured in an air–liquid interface and topically exposed to 20 chemicals, including true positive, misleading positive and true negative genotoxins. Based on the results obtained in the present study, the sensitivity, specificity and accuracy of the ex vivo skin comet assay to predict in vivo genotoxicity were 89%, 90% and 89%, respectively. Donor and experimental variability were mainly reflected in the magnitude of the response and not the difference between the presence and absence of a genotoxic response. The present study indicates that human skin obtained from surgery is a promising and robust model for safety evaluation of chemicals that are in direct contact with the skin. -- Highlights: ► We use human skin obtained from surgery for genotoxicity evaluation of chemicals. ► We use the comet assay as parameter for genotoxicity in ex vivo human skin. ► Sensitivity, specificity and accuracy to predict in vivo genotoxins are determined. ► Sensitivity, specificity and accuracy are 89%, 90% and 90%, respectively. ► The method is suitable for evaluation of chemicals that are in contact with skin.« less

Genotoxicity assessment of an energetic propellant compound, 3-nitro-1,2,4-triazol-5-one (NTO).

PubMed

Reddy, Gunda; Song, Jian; Kirby, Paul; Lent, Emily M; Crouse, Lee C B; Johnson, Mark S

2011-02-03

3-Nitro-1,2,4-triazol-5-one (NTO) is an energetic explosive proposed for use in weapon systems, to reduce the sensitivity of warheads. In order to develop toxicity data for safety assessment, we investigated the genotoxicity of NTO, using a battery of genotoxicity tests, which included the Ames test, Chinese Hamster Ovary (CHO) cell chromosome aberration test, L5178Y TK(+/-) mouse lymphoma mutagenesis test and rat micronucleus test. NTO was not mutagenic in the Ames test or in Escherichia coli (WP2uvrA). NTO did not induce chromosomal aberrations in CHO cells, with or without metabolic activation. In the L5178Y TK(+/-) mouse lymphoma mutagenesis test, all of the NTO-treated cultures had mutant frequencies that were similar to the average frequencies of solvent control-treated cultures, indicating a negative result. Confirmatory tests for the three in vitro tests also produced negative results. The potential in vivo clastogenicity and aneugenicity of NTO was evaluated using the rat peripheral blood micronucleus test. NTO was administered by oral gavage to male and female Sprague-Dawley rats for 14 days at doses up to 2g/kg/day. Flow cytometric analysis of peripheral blood demonstrated no significant induction of micronucleated reticulocytes relative to the vehicle control (PEG-200). These studies reveal that NTO was not genotoxic in either in vitro or in vivo tests and suggest a low risk of genetic hazards associated with exposure. Copyright © 2010 Elsevier B.V. All rights reserved.

Acute toxicity and genotoxic activity of avocado seed extract (Persea americana Mill., c.v. Hass).

PubMed

Padilla-Camberos, Eduardo; Martínez-Velázquez, Moisés; Flores-Fernández, José Miguel; Villanueva-Rodríguez, Socorro

2013-01-01

The use of vegetal extracts requires toxicological and genotoxic evaluations to establish and verify safety before being added to human cosmetic, pharmaceutical medicine, or alimentary products. Persea americana seeds have been used in traditional medicine as treatment for several diseases. In this work, the ethanolic seed extract of Persea americana was evaluated with respect to its genotoxic potential through micronucleus assay in rodents. The frequency of micronuclei in groups of animals treated with avocado seed extract showed no differences compared to the negative control (vehicle); therefore, it is considered that the avocado seed extract showed no genotoxic activity in the micronucleus test.

Acute Toxicity and Genotoxic Activity of Avocado Seed Extract (Persea americana Mill., c.v. Hass)

PubMed Central

Padilla-Camberos, Eduardo; Martínez-Velázquez, Moisés; Flores-Fernández, José Miguel; Villanueva-Rodríguez, Socorro

2013-01-01

The use of vegetal extracts requires toxicological and genotoxic evaluations to establish and verify safety before being added to human cosmetic, pharmaceutical medicine, or alimentary products. Persea americana seeds have been used in traditional medicine as treatment for several diseases. In this work, the ethanolic seed extract of Persea americana was evaluated with respect to its genotoxic potential through micronucleus assay in rodents. The frequency of micronuclei in groups of animals treated with avocado seed extract showed no differences compared to the negative control (vehicle); therefore, it is considered that the avocado seed extract showed no genotoxic activity in the micronucleus test. PMID:24298206

Genotoxicity and apoptosis in Drosophila melanogaster exposed to benzene, toluene and xylene: Attenuation by quercetin and curcumin

DOE Office of Scientific and Technical Information (OSTI.GOV)

Singh, Mahendra P.; Mishra, M.; Sharma, A.

2011-05-15

Monocyclic aromatic hydrocarbons (MAHs) such as benzene, toluene and xylene are being extensively used for various industrial and household purposes. Exposure to these hydrocarbons, occupationally or non-occupationally, is harmful to organisms including human. Several studies tested for toxicity of benzene, toluene and xylene, and interestingly, only a few studies looked into the attenuation. We used Drosophila model to test the genotoxic and apoptotic potential of these compounds and subsequently evaluated the efficiency of two phytochemicals, namely, quercetin and curcumin in attenuating test chemical induced toxicity. We exposed third instar larvae of wild type Drosophila melanogaster (Oregon R{sup +}) to 1.0-100.0more » mM benzene, toluene or xylene, individually, for 12, 24 and 48 h and examined their apoptotic and genotoxic potential. We observed significantly (P < 0.001) increased apoptotic markers and genotoxicity in a concentration- and time-dependent manner in organisms exposed to benzene, toluene or xylene. We also observed significantly (P < 0.001) increased cytochrome P450 activity in larvae exposed to test chemicals and this was significantly reduced in the presence of 3',4'-dimethoxyflavone, a known Aryl hydrocarbon receptor (AhR) blocker. Interestingly, we observed a significant reduction in cytochrome P450 activity, GST levels, oxidative stress parameters, genotoxic and apoptotic endpoints when organisms were exposed simultaneously to test chemical along with quercetin or curcumin. The study further suggests the suitability of D. melanogaster as an alternate animal model for toxicological studies involving benzene, toluene and xylene and its potential in studying the protective role(s) of phytochemicals.« less

Effects of soil pH on the Vicia-micronucleus genotoxicity assay.

PubMed

Dhyèvre, Adrien; Foltête, Anne Sophie; Aran, Delphine; Muller, Serge; Cotelle, Sylvie

2014-11-01

In the field of contaminated sites and soil management, chemical analyses only bring typological data about pollution. As far as bioavailability and effects on organisms are concerned, we need ecotoxicology tools. In this domain, among many existing tests, we chose to study genotoxicity because it is a short-term endpoint with long-term consequences. The aim of this study is to assess the effects of soil pH on the results of the Vicia faba root tip micronucleus test for the two following reasons: (i) to define the pH range within which the test can be performed without modifying the soil to be tested, within the framework of the ISO standard of the test and (ii) to provides information about the effects of the pH on the genotoxic potential of soils. In this context, we modified the pH of a standard soil with HCl or NaOH and we spiked the matrix with copper (2, 4 and 8 mmol kg(-1) dry soil) or with maleic hydrazide, an antigerminative chemical (5, 10 and 20 μmol kg(-1) dry soil). We concluded that the pH had no effect on the mitotic index or micronucleus frequency in the root cells of the negative controls: extreme pH values did not induce micronucleus formation in root cells. Moreover, according to our results, the Vicia-micronucleus test can be performed with pH values ranging between 3.2 and 9.0, but in the ISO 29200 "Soil quality--assessment of genotoxic effects on higher plants--V. faba micronucleus test" we recommended to use a control soil with a pH value ranging between 5 and 8 for a more accurate assessment of chemical genotoxicity. We also found that acid pH could increase the genotoxic potential of pollutants, especially heavy metals. With hydrazide maleic spiked soil, plants were placed in a situation of double stress, i.e. toxicity caused by extreme pH values and toxicity induced by the pollutant. Copyright © 2014 Elsevier B.V. All rights reserved.

Evaluation of Genotoxicity and 28-day Oral Dose Toxicity on Freeze-dried Powder of Tenebrio molitor Larvae (Yellow Mealworm).

PubMed

Han, So-Ri; Yun, Eun-Young; Kim, Ji-Young; Hwang, Jae Sam; Jeong, Eun Ju; Moon, Kyoung-Sik

2014-06-01

The larval form of Tenebrio molitor (T. molitor) has been eaten in many countries and provides benefits as a new food source of protein for humans. However, no information exists regarding its safety for humans. The objective of the present study was to evaluate the genotoxicity and repeated dose oral toxicity of the freeze-dried powder of T. molitor larvae. The genotoxic potential was evaluated by a standard battery testing: bacterial reverse mutation test, in vitro chromosome aberration test, and in vivo micronucleus test. To assess the repeated dose toxicity, the powder was administered once daily by oral gavage to Sprague-Dawley (SD) rats at dose levels of 0, 300, 1000 and 3000 mg/kg/day for 28 days. The parameters which were applied to the study were mortality, clinical signs, body and organ weights, food consumption, ophthalmology, urinalysis, hematology, serum chemistry, gross findings and histopathologic examination. The freezedried powder of T. molitor larvae was not mutagenic or clastogenic based on results of in vitro and in vivo genotoxicity assays. Furthermore, no treatment-related changes or findings were observed in any parameters in rats after 28 days oral administration. In conclusion, the freeze-dried powder of T. molitor larvae was considered to be non-genotoxic and the NOAEL (No Observed Adverse Effect Level) was determined to be 3000 mg/kg/day in both sexes of SD rats under our experimental conditions.

Evaluation of Genotoxicity and 28-day Oral Dose Toxicity on Freeze-dried Powder of Tenebrio molitor Larvae (Yellow Mealworm)

PubMed Central

Han, So-Ri; Yun, Eun-Young; Kim, Ji-Young; Hwang, Jae Sam; Jeong, Eun Ju

2014-01-01

The larval form of Tenebrio molitor (T. molitor) has been eaten in many countries and provides benefits as a new food source of protein for humans. However, no information exists regarding its safety for humans. The objective of the present study was to evaluate the genotoxicity and repeated dose oral toxicity of the freeze-dried powder of T. molitor larvae. The genotoxic potential was evaluated by a standard battery testing: bacterial reverse mutation test, in vitro chromosome aberration test, and in vivo micronucleus test. To assess the repeated dose toxicity, the powder was administered once daily by oral gavage to Sprague-Dawley (SD) rats at dose levels of 0, 300, 1000 and 3000 mg/kg/day for 28 days. The parameters which were applied to the study were mortality, clinical signs, body and organ weights, food consumption, ophthalmology, urinalysis, hematology, serum chemistry, gross findings and histopathologic examination. The freezedried powder of T. molitor larvae was not mutagenic or clastogenic based on results of in vitro and in vivo genotoxicity assays. Furthermore, no treatment-related changes or findings were observed in any parameters in rats after 28 days oral administration. In conclusion, the freeze-dried powder of T. molitor larvae was considered to be non-genotoxic and the NOAEL (No Observed Adverse Effect Level) was determined to be 3000 mg/kg/day in both sexes of SD rats under our experimental conditions. PMID:25071922

Use of low density polyethylene membranes for assessment of genotoxicity of PAHs in the Seine River.

PubMed

Vincent-Hubert, Françoise; Uher, Emmanuelle; Di Giorgio, Carole; Michel, Cécile; De Meo, Michel; Gourlay-France, Catherine

2017-03-01

The genotoxicity of river water dissolved contaminants is usually estimated after grab sampling of river water. Water contamination can now be obtained with passive samplers that allow a time-integrated sampling of contaminants. Since it was verified that low density polyethylene membranes (LDPE) accumulate labile hydrophobic compounds, their use was proposed as a passive sampler. This study was designed to test the applicability of passive sampling for combined chemical and genotoxicity measurements. The LDPE extracts were tested with the umu test (TA1535/pSK1002 ± S9) and the Ames assay (TA98, TA100 and YG1041 ± S9). We describe here this new protocol and its application in two field studies on four sites of the Seine River. Field LDPE extracts were negative with the YG1041 and TA100 and weakly positive with the TA98 + S9 and Umu test. Concentrations of labile mutagenic PAHs were higher upstream of Paris than downstream of Paris. Improvement of the method is needed to determine the genotoxicity of low concentrations of labile dissolved organic contaminants.

Differences in genotoxic activity of alpha-Ni3S2 on human lymphocytes from nickel-hypersensitized and nickel-unsensitized donors.

PubMed

Arrouijal, F Z; Marzin, D; Hildebrand, H F; Pestel, J; Haguenoer, J M

1992-05-01

The genotoxic activity of alpha-Ni3S2 was assessed on human lymphocytes from nickel-hypersensitized (SSL) and nickel-unsensitized (USL) subjects. Three genotoxicity tests were performed: the sister chromatid exchange (SCE) test, the metaphase analysis test and the micronucleus test. (i) The SCE test (3-100 micrograms/ml) showed a weak but statistically significant increase in the number of SCE in both lymphocyte types with respect to controls, USL presenting a slightly higher SCE incidence but only at one concentration. (ii) The metaphase analysis test demonstrated a high dose-dependent clastogenic activity of alpha-Ni3S2 in both lymphocyte types. The frequency of chromosomal anomalies was significantly higher in USL than in SSL for all concentrations applied. (iii) The micronucleus test confirmed the dose-dependent clastogenic activity of alpha-Ni3S2 and the differences already observed between USL and SSL, i.e. the number of cells with micronuclei was statistically higher in USL. Finally, the incorporation study with alpha-63Ni3S2 showed a higher uptake of its solubilized fraction by USL. This allows an explanation of the different genotoxic action of nickel on the two cell types. In this study we demonstrated that hypersensitivity has an influence on the incorporation of alpha-Ni3S2 and subsequently on the different induction of chromosomal aberrations in human lymphocytes.

Application of bacterial reverse mutation assay for detection of non-genotoxic carcinogens.

PubMed

Kanode, Rewan; Chandra, Saurabh; Sharma, Sharad

2017-06-01

Non-genotoxic carcinogens may play a significant role in development of cancer. Currently short-term assays for mutagenicity classify genotoxic carcinogens and lack the abilities to detect epigenetic carcinogens. The need to develop an endpoint always remains to recognize potentially carcinogenic agents employing rapid and practical bioassays. For this, the present study utilized TA98 and TA1537 tester strains of Salmonella typhimurium to evaluate four non-genotoxic carcinogenic agents (Coumarin, β-Myrcene, Bis(2-ethylhexyl) phthalate and trans-anethole). These chemicals were tested individually and in combination with promutagens 2-aminoanthracene (2AA) and benzo(a)pyrene (BP) in presence of metabolic activation system (S9) by plate incorporation method. Exposure to all four test chemicals revealed marked increase of revertant colonies in promutagen combined groups as compared to promutagens alone. However significantly greater fold responses were observed with 2AA combination groups (Coumarin +2AA, β-Myrcene +2AA, Bis(2-ethylhexyl) phthalate +2AA and trans-anethole +2AA) with TA98 strain as compared with TA1537, which seems to have enhanced the mutagenic response of 2AA in metabolically activated conditions. It is concluded that out of both tester strains TA98 strain of Salmonella typhimurium has the potential to detect non-genotoxic carcinogens when combined with potent promutgens either by inhibiting or modulating activities of liver microsomal enzymes biochemically which may indirectly contribute to neoplastic alterations. Further this simple, short-term alternative assay may provide rapid information during extrapolative toxicology for differentiating genotoxic and non-genotoxic carcinogens.

Genotoxic evaluation of an industrial effluent from an oil refinery using plant and animal bioassays.

PubMed

Rodrigues, Fernando Postalli; Angeli, José Pedro Friedmann; Mantovani, Mário Sérgio; Guedes, Carmen Luisa Barbosa; Jordão, Berenice Quinzani

2010-01-01

Polycyclic aromatic hydrocarbons (PAHs) are genotoxic chemicals commonly found in effluents from oil refineries. Bioassays using plants and cells cultures can be employed for assessing environmental safety and potential genotoxicity. In this study, the genotoxic potential of an oil refinery effluent was analyzed by means of micronucleus (MN) testing of Alium cepa, which revealed no effect after 24 h of treatment. On the other hand, primary lesions in the DNA of rat (Rattus norvegicus) hepatoma cells (HTC) were observed through comet assaying after only 2 h of exposure. On considering the capacity to detect DNA damage of a different nature and of these cells to metabolize xenobiotics, we suggest the association of the two bioassays with these cell types, plant (Allium cepa) and mammal (HTC) cells, for more accurately assessing genotoxicity in environmental samples.

Evaluation of genotoxic potential of neurotoxin anatoxin-a with the use of umuC test.

PubMed

Sieroslawska, Anna; Rymuszka, Anna

2010-01-01

The aim of this study was to evaluate genotoxicity of anatoxin-a, cyanotoxin of neurotoxic activity. Additionally, other frequently detected cyanotoxin of previously described genotoxic potential, microcystin-LR, was used at the same concentrations, as well as the mixture of both toxins, anatoxin-a and microcystin-LR. Genotoxicity of the toxins was determined with the use of the umuC assay, in which the induction and expression of the umuC - lacZ reporter gene was assessed. The test was conducted on Salmonella typhimurium TA 1535/pSK1002 strain, with and without metabolic transformation. The toxin concentrations were 0.25, 0.5, 1 and 2 µg/ml. The exposure time was 2 h. The highest inefficient concentration of anatoxin-a without metabolic transformation was 0.25 µg/ml, of microcystin-LR was 0.5 µg/ml and in case of the toxin mixture all used concentrations induced the umuC gene. When S9 fraction was added to the samples, no effects were detected. To our knowledge, this is the first report on genotoxic effects of anatoxin-a. Although the study is preliminary and needs further research, however, indicates the new potential activity of the toxin, as well as the possible increase of genotoxicity of other cyanotoxins, more stable in the environment, e.g. microcystin-LR.

The Cosmetics Europe strategy for animal-free genotoxicity testing: project status up-date.

PubMed

Pfuhler, S; Fautz, R; Ouedraogo, G; Latil, A; Kenny, J; Moore, C; Diembeck, W; Hewitt, N J; Reisinger, K; Barroso, J

2014-02-01

The Cosmetics Europe (formerly COLIPA) Genotoxicity Task Force has driven and funded three projects to help address the high rate of misleading positives in in vitro genotoxicity tests: The completed "False Positives" project optimized current mammalian cell assays and showed that the predictive capacity of the in vitro micronucleus assay was improved dramatically by selecting more relevant cells and more sensitive toxicity measures. The on-going "3D skin model" project has been developed and is now validating the use of human reconstructed skin (RS) models in combination with the micronucleus (MN) and Comet assays. These models better reflect the in use conditions of dermally applied products, such as cosmetics. Both assays have demonstrated good inter- and intra-laboratory reproducibility and are entering validation stages. The completed "Metabolism" project investigated enzyme capacities of human skin and RS models. The RS models were shown to have comparable metabolic capacity to native human skin, confirming their usefulness for testing of compounds with dermal exposure. The program has already helped to improve the initial test battery predictivity and the RS projects have provided sound support for their use as a follow-up test in the assessment of the genotoxic hazard of cosmetic ingredients in the absence of in vivo data. Copyright © 2013 Elsevier Ltd. All rights reserved.

Application of in vitro cell transformation assays in regulatory toxicology for pharmaceuticals, chemicals, food products and cosmetics.

PubMed

Vanparys, Philippe; Corvi, Raffaella; Aardema, Marilyn J; Gribaldo, Laura; Hayashi, Makoto; Hoffmann, Sebastian; Schechtman, Leonard

2012-04-11

Two year rodent bioassays play a key role in the assessment of carcinogenic potential of chemicals to humans. The seventh amendment to the European Cosmetics Directive will ban in 2013 the marketing of cosmetic and personal care products that contain ingredients that have been tested in animal models. Thus 2-year rodent bioassays will not be available for cosmetics/personal care products. Furthermore, for large testing programs like REACH, in vivo carcinogenicity testing is impractical. Alternative ways to carcinogenicity assessment are urgently required. In terms of standardization and validation, the most advanced in vitro tests for carcinogenicity are the cell transformation assays (CTAs). Although CTAs do not mimic the whole carcinogenesis process in vivo, they represent a valuable support in identifying transforming potential of chemicals. CTAs have been shown to detect genotoxic as well as non-genotoxic carcinogens and are helpful in the determination of thresholds for genotoxic and non-genotoxic carcinogens. The extensive review on CTAs by the OECD (OECD (2007) Environmental Health and Safety Publications, Series on Testing and Assessment, No. 31) and the proven within- and between-laboratories reproducibility of the SHE CTAs justifies broader use of these methods to assess carcinogenic potential of chemicals. Copyright © 2012 Elsevier B.V. All rights reserved.

Black pepper constituent piperine: genotoxicity studies in vitro and in vivo.

PubMed

Thiel, Anette; Buskens, Carin; Woehrle, Tina; Etheve, Stéphane; Schoenmakers, Ankie; Fehr, Markus; Beilstein, Paul

2014-04-01

Piperine is responsible for the hot taste of black pepper. Publications on genotoxicity of piperine are reported: negative Ames Tests and one in vitro micronucleus test (MNT). In vivo tests were mainly negative. In the majority of the data the administered dose levels did not follow the dose selection requirements of regulatory guidelines of having dose levels up to the maximum tolerated dose (MTD). The only oral high dose studies were a positive in vivo MNT in mice in contrast to a negative in vivo chromosome aberration test in rats. Thus, conflicting results in genotoxicity testing are published. To investigate this further, we administered piperine to mice up to the MTD and determined micronuclei-frequency. Piperine reduces core body temperature and interferes with blood cells both being known to result in irrelevant positive in vivo MNTs. Therefore we added mechanistic endpoints: core body temperature, haematology, erythropoietin level, and organ weights. Additionally an in vitro MNT in Chinese hamster ovary cells was performed. Piperine was negative in the in vitro MNT. It caused significant reduction of core body temperature, decrease of white blood cells and spleen weights but no increase in the micronucleus-frequency. Thus, in our studies piperine was not genotoxic. Copyright © 2014 Elsevier Ltd. All rights reserved.

Molecular and structural changes induced by essential oils treatments in Vicia faba roots detected by genotoxicity testing.

PubMed

Sturchio, Elena; Boccia, Priscilla; Zanellato, Miriam; Meconi, Claudia; Donnarumma, Lucia; Mercurio, Giuseppe; Mecozzi, Mauro

2016-01-01

Over the last few years, there has been an increased interest in exploiting allelopathy in organic agriculture. The aim of this investigation was to examine the effects of essential oil mixtures in order to establish their allelopathic use in agriculture. Two mixtures of essential oils consisting respectively of tea tree oil (TTO) and clove plus rosemary (C + R) oils were tested. Phytotoxicity and genotoxicity tests on the root meristems of Vicia faba minor were performed. A phytotoxic influence was particularly relevant for C + R mixture, while genotoxicity tests revealed significant results with both C + R oil mixture and TTO. Phenotypic analysis on Vicia faba minor primary roots following C + R oil mixture treatment resulted in callose production, an early symptom attributed to lipid peroxidation. The approach described in this study, based on genotoxicity bioassays, might identify specific DNA damage induced by essential oil treatments. These tests may represent a powerful method to evaluate potential adverse effects of different mixtures of essential oils that might be useful in alternative agriculture. Future studies are focusing on the positive synergism of more complex mixtures of essential oils in order to reduce concentrations of potentially toxic components while at the same time maintaining efficacy in antimicrobial and antifungal management.

Evaluation of Genotoxic and Mutagenic Activity of Organic Extracts from Drinking Water Sources

PubMed Central

Guan, Ying; Wang, Xiaodong; Wong, Minghung; Sun, Guoping; An, Taicheng; Guo, Jun

2017-01-01

An increasing number of industrial, agricultural and commercial chemicals in the aquatic environment lead to various deleterious effects on organisms, which is becoming a serious global health concern. In this study, the Ames test and SOS/umu test were conducted to investigate the potential genotoxicity and mutagenicity caused by organic extracts from drinking water sources. Organic content of source water was extracted with XAD-2 resin column and organic solvents. Four doses of the extract equivalent to 0.25, 0.5, 1 and 2L of source water were tested for toxicity. All the water samples were collected from six different locations in Guangdong province. The results of the Ames test and SOS/umu test showed that all the organic extracts from the water samples could induce different levels of DNA damage and mutagenic potentials at the dose of 2 L in the absence of S9 mix, which demonstrated the existence of genotoxicity and mutagenicity. Additionally, we found that Salmonella typhimurium strain TA98 was more sensitive for the mutagen. Correlation analysis between genotoxicity, Organochlorine Pesticides (OCPs) and Polycyclic Aromatic Hydrocarbons (PAHs) showed that most individual OCPs were frame shift toxicants in drinking water sources, and there was no correlation with total OCPs and PAHs. PMID:28125725

THE GENOTOXICITY OF AMBIENT OUTDOOR AIR, A REVIEW: SALMONELLA MUTAGENICITY

EPA Science Inventory

The genotoxicity of ambient outdoor air, a review: Salmonella mutagenicity

Abstract
Mutagens in urban air pollution come from anthropogenic sources (especially combustion sources) and are products of airborne chemical reactions. Bacterial mutation tests have been used ...

Lethal and sublethal effects of marine sediment extracts on fish cells and chromosomes

NASA Astrophysics Data System (ADS)

Landolt, Marsha L.; Kocan, Richard M.

1984-03-01

The cost of conducting conventional chronic bioassays with every potentially toxic compound found in marine ecosystems is prohibitive; therefore short-term toxicity tests which can be used for rapid screening were developed. The tests employ cultured fish cells to measure lethal, sublethal or genotoxic effects of pure compounds and complex mixtures. The sensitivity of these tests has been proven under laboratory conditions; the following study used two of these tests, the anaphase aberration test and a cytotoxicity assay, under field conditions. Sediment was collected from 97 stations within Puget Sound, Washington. Serial washings of the sediment in methanol and dichloromethane yielded an organic extract which was dried, dissolved in DMSO and incubated as a series of dilutions with rainbow trout gonad (RTG-2) cells. The toxic effects of the extract were measured by examining the rate of cell proliferation and the percentage of damaged anaphase figures. Anaphase figures were considered to be abnormal if they exhibited non-disjunctions, chromosome fragments, or chromosome bridges. A second cell line (bluegill fry, BF-2) was also tested for cell proliferation and was included because, unlike the RTG-2 cell line, it contains little or no mixed function oxygenase activity. Of 97 stations tested, 35 showed no genotoxic activity, 42 showed high genotoxic activity (P≤.01) and the remainder were intermediate. Among the toxic sites were several deep water stations adjacent to municipal sewage outfalls and four urban waterways contaminated by industrial and municipal effluents. Extracts from areas that showed genotoxic effects also inhibited cell proliferation and were cytotoxic to RTG-2 cells. Few effects were noted in the MFO deficient BF-2 cells. Short term in vitro tests provide aquatic toxicologists with a versatile and cost effective tool for screening complex environments. Through these tests one can identify compounds or geographic regions that exhibit high cytotoxic or genotoxic potential.

Comet assay evaluation of six chemicals of known genotoxic potential in rats.

PubMed

Hobbs, Cheryl A; Recio, Leslie; Streicker, Michael; Boyle, Molly H; Tanaka, Jin; Shiga, Atsushi; Witt, Kristine L

2015-07-01

As a part of an international validation of the in vivo rat alkaline comet assay (comet assay) initiated by the Japanese Center for the Validation of Alternative Methods (JaCVAM) we examined six chemicals for potential to induce DNA damage: 2-acetylaminofluorene (2-AAF), N-nitrosodimethylamine (DMN), o-anisidine, 1,2-dimethylhydrazine dihydrochloride (1,2-DMH), sodium chloride, and sodium arsenite. DNA damage was evaluated in the liver and stomach of 7- to 9-week-old male Sprague Dawley rats. Of the five genotoxic carcinogens tested in our laboratory, DMN and 1,2-DMH were positive in the liver and negative in the stomach, 2-AAF and o-anisidine produced an equivocal result in liver and negative results in stomach, and sodium arsenite was negative in both liver and stomach. 1,2-DMH and DMN induced dose-related increases in hedgehogs in the same tissue (liver) that exhibited increased DNA migration. However, no cytotoxicity was indicated by the neutral diffusion assay (assessment of highly fragmented DNA) or histopathology in response to treatment with any of the tested chemicals. Therefore, the increased DNA damage resulting from exposure to DMN and 1,2-DMH was considered to represent a genotoxic response. Sodium chloride, a non-genotoxic non-carcinogen, was negative in both tissues as would be predicted. Although only two (1,2-DMH and DMN) out of five genotoxic carcinogens produced clearly positive results in the comet assay, the results obtained for o-anisidine and sodium arsenite in liver and stomach cells are consistent with the known mode of genotoxicity and tissue specificity exhibited by these carcinogens. In contrast, given the known genotoxic mode-of-action and target organ carcinogenicity of 2-AAF, it is unclear why this chemical failed to convincingly increase DNA migration in the liver. Thus, the results of the comet assay validation studies conducted in our laboratory were considered appropriate for five out of the six test chemicals. Copyright © 2015 Elsevier B.V. All rights reserved.

Comet assay evaluation of six chemicals of known genotoxic potential in rats

PubMed Central

Hobbs, Cheryl A.; Recio, Leslie; Streicker, Michael; Boyle, Molly H.; Tanaka, Jin; Shiga, Atsushi; Witt, Kristine L.

2015-01-01

As a part of an International validation of the in vivo rat alkaline comet assay (comet assay) initiated by the Japanese Center for the Validation of Alternative Methods (JaCVAM) we examined six chemicals for potential to induce DNA damage: 2-acetylaminofluorene (2-AAF), N-nitrosodimethylamine (DMN), o-anisidine, 1,2-dimethylhydrazine dihydrochloride (1,2-DMH), sodium chloride, and sodium arsenite. DNA damage was evaluated in the liver and stomach of 7- to 9-week-old male Sprague Dawley rats. Of the five genotoxic carcinogens tested in our laboratory, DMN and 1,2-DMH were positive in the liver and negative in the stomach, 2-AAF and o-anisidine produced an equivocal result in liver and negative results in stomach, and sodium arsenite was negative in both liver and stomach. 1,2-DMH and DMN induced dose-related increases in hedgehogs in the same tissue (liver) that exhibited increased DNA migration. However, no cytotoxicity was indicated by the neutral diffusion assay (assessment of highly fragmented DNA) or histopathology in response to treatment with any of the tested chemicals. Therefore, the increased DNA damage resulting from exposure to DMN and 1,2-DMH was considered to represent a genotoxic response. Sodium chloride, a non-genotoxic non-carcinogen, was negative in both tissues as would be predicted. Although only two (1,2-DMH and DMN) out of five genotoxic carcinogens produced clearly positive results in the comet assay, the results obtained for o-anisidine and sodium arsenite in liver and stomach cells are consistent with the known mode of genotoxicity and tissue specificity exhibited by these carcinogens. In contrast, given the known genotoxic mode-of-action and target organ carcinogenicity of 2-AAF, it is unclear why this chemical failed to convincingly increase DNA migration in the liver. Thus, the results of the comet assay validation studies conducted in our laboratory were considered appropriate for five out of the six test chemicals. PMID:26212309

Comparative study of the mutagenic and genotoxic activity associated with inhalable particulate matter in Rio de Janeiro air

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miguel, A.G.; Daisey, J.M.; Sousa, J.A.

1990-01-01

We have determined the genotoxic and mutagenic activities associated with inhalable particulate matter (IPM) collected in Rio de Janeiro, Brazil, Camden, NJ, and Caldecott Tunnel, CA, and used these results to compare three different bioassays. Samples collected every 12 hr (Rio) or every 24 hr (Camden) were extracted sequentially with cyclohexane (CX), dichloromethane (DCM), and acetone (ACE), for a rough fractionation by polarity, and composites of the extracts were tested for mutagenicity using the Salmonella frame shift (TA98) and base substitution (TA100) tester strains, as well as for genotoxicity using the Rossman Microscreen bioassay based on the induction of lambda-prophagemore » in a lysogenic Escherichia coli strain. All samples were tested without and with S9 metabolic activation. Maximum mutagenic and genotoxic activities were in the nonpolar (CX) and polar (ACE) fractions, respectively, indicating that these two assays detect different classes of compounds with different efficiencies. Oxidative aging of the Rio aerosol is indicated by a shift in activities in both tests from the less polar fractions in the day to the polar (ACE) fraction at night. The Rio TA98 mutagenic (18 rev/m3) and genotoxic (1.4 x 10(5) PFU/m3) activities were higher than those for Camden, an Eastern U.S. city, by factors of 1.4 and 2.8, respectively.« less

Evaluation of genotoxic potential of avarol, avarone, and its methoxy and methylamino derivatives in prokaryotic and eukaryotic test models.

PubMed

Kolarević, Stoimir; Milovanović, Dragana; Kračun-Kolarević, Margareta; Kostić, Jovana; Sunjog, Karolina; Martinović, Rajko; Đorđević, Jelena; Novaković, Irena; Sladić, Dušan; Vuković-Gačić, Branka

2018-01-04

In this study, mutagenic and genotoxic potential of anti-tumor compounds avarol, avarone, and its derivatives 3'-methoxyavarone, 4'-(methylamino)avarone and 3'-(methylamino)avarone was evaluated and compared to cytostatics commonly used in chemotherapy (5-fluorouracil, etoposid, and cisplatin). Mutagenic potential of selected hydroquinone and quinones was assessed in prokaryotic model by the SOS/umuC assay in Salmonella typhimurium TA1535/pSK1002. Genotoxic potential was also assessed in eukaryotic models using comet assay in human fetal lung cell line (MRC-5), human adenocarcinoma epithelial cell line (A549), and in human peripheral blood cells (HPBC). The results indicated that avarol and avarone do not exert mutagenic/genotoxic potential. Among the studied avarone derivatives, mutagenic potential was detected by SOS/umuC test for 3'-(methylamino)avarone, but only after metabolic activation. The results of comet assay indicated that 3'-methoxyavarone and 3'-(methylamino)avarone have a significant impact on the level of DNA damage in the MRC-5 cell line. Genotoxic potential was not observed in A549 cells or HPBC probably due to a different uptake rate for the compounds and lower in metabolism rate within these cells.

Genotoxicity, acute oral and dermal toxicity, eye and dermal irritation and corrosion and skin sensitisation evaluation of silver nanoparticles.

PubMed

Kim, Jin Sik; Song, Kyung Seuk; Sung, Jae Hyuck; Ryu, Hyun Ryol; Choi, Byung Gil; Cho, Hyun Sun; Lee, Jin Kyu; Yu, Il Je

2013-08-01

To clarify the health risks related to silver nanoparticles (Ag-NPs), we evaluated the genotoxicity, acute oral and dermal toxicity, eye irritation, dermal irritation and corrosion and skin sensitisation of commercially manufactured Ag-NPs according to the OECD test guidelines and GLP. The Ag-NPs were not found to induce genotoxicity in a bacterial reverse mutation test and chromosomal aberration test, although some cytotoxicity was observed. In acute oral and dermal toxicity tests using rats, none of the rats showed any abnormal signs or mortality at a dose level of ∼ 2000 mg/kg. Similarly, acute eye and dermal irritation and corrosion tests using rabbits revealed no significant clinical signs or mortality and no acute irritation or corrosion reaction for the eyes and skin. In a skin sensitisation test using guinea pigs, one animal (1/20) showed discrete or patchy erythema, thus Ag-NPs can be classified as a weak skin sensitiser.

Genotoxicity of the Musi River (Hyderabad, India) investigated with the VITOTOX test.

PubMed

Vijayashree, B; Ahuja, Y R; Regniers, L; Rao, V; Verschaeve, L

2005-01-01

The bacterial VITOTOX genotoxicity test was used to screen water samples collected from three different stations along the banks of the river Musi, in Hyderabad, India. Water was collected at three stations that differed from each other in the nature of the surrounding industrial and other activities. A number of different pollutants were also measured in water, soil and air samples. The three stations were found highly polluted and different with regard to the genotoxicity and toxicity of their samples. These results demonstrate the need for further biological studies in this area to generate valuable data on genomic instability, risk assessment of cancer, and to provide avenues for risk management.

[Evaluation of cyto- and genotoxic action of ferronanomagnetic and constant magnetic field in in vivo system].

PubMed

Chekhun, V F; Lozovs'ka, Iu V; Luk'ianova, N Iu; Demash, D V; Todor, I M; Nalieskina, L A

2013-01-01

Cyto- and genotoxic effects of nanoparticles on the basis of FM, CMF or their combination have been studied in AKE cells, BM cells of erythroid line, and peripheral blood lymphocytes with the use of MN test and "DNA-comet" assay. It has been shown that expression of mentioned effects is related to FM concentration and duration of tested agent action. It has been also demonstrated that action of CMF alone in the studied cells did not cause any changes in cell architectonics or affect MN counts which are associated with DNA damage. When FM and CMF were used in combination there has been observed the phenomenon of induction of CMF action with FM nanoparticles. The obtained results allow recommend MN test and "DNA-comet" assay as the markers of genome stability in the tests of genotoxic effects of nanomaterials for development of vector nanosystems.

Considerations on photochemical genotoxicity. II: report of the 2009 International Workshop on Genotoxicity Testing Working Group.

PubMed

Lynch, Anthony M; Guzzie, Peggy J; Bauer, Daniel; Gocke, Elmar; Itoh, Satoru; Jacobs, Abby; Krul, Cyrille A M; Schepky, Andreas; Tanaka, Noriho; Kasper, Peter

2011-08-16

A workshop to reappraise the previous IWGT recommendations for photogenotoxicity testing [E. Gocke, L. Muller, P.J. Guzzie, S. Brendler-Schwaab, S. Bulera, C.F. Chignell, L.M. Henderson, A. Jacobs, H. Murli, R.D. Snyder, N. Tanaka, Considerations on photochemical genotoxicity: report of the International Workshop on Genotoxicity Test Procedures working group, Environ. Mol. Mutagen., 35 (2000) 173-184] was recently held as part of the 5th International Workshop on Genotoxicity Testing (IWGT) meeting in Basel, Switzerland (August 17-19, 2009). An Expert Panel was convened from regulatory, academic and industrial scientists (with several members serving on the original panel) and chaired by Dr Peter Kasper (BfArM, Germany). The aim of the workshop was to review progress made in photo(geno)toxicity testing over the past decade; a period which saw the introduction of several regulatory photosafety guidances in particular in Europe and the USA. Based on current regulatory guidelines a substantial proportion of compounds trigger the requirements for photosafety testing. Moreover, there has been growing concern within industry about the performance of the in vitro photosafety tests in the "real world" of compound development. Therefore, the expert group reviewed the status of the current regulatory guidance's and the impact these have had on compound development in the context of the various triggers for photosafety testing. In addition, the performance of photogenotoxicity assays (old and new) was discussed, particularly in view of reports of pseudophotoclastogencity. The Expert Panel finished with an assessment of the positioning of photogenotoxicity testing within a photosafety testing strategy. The most significant conclusion made by the Expert Panel was that photogenotoxicity testing should no longer be recommended as part of the standard photosafety testing strategy. In addition, progress was made on the refinement of triggers for photosafety testing. For example, there was support for harmonisation of methods to determine the Molar Extinction Coefficient (MEC) and a consensus agreement that there should be no requirement for testing of compounds with a MEC<1000Lmol(-1)cm(-1). Copyright © 2011 Elsevier B.V. All rights reserved.

Antigenotoxic and free radical scavenging activities of extracts from Moricandia arvensis.

PubMed

Skandrani, I; Sghaier, M Ben; Neffati, A; Boubaker, J; Bouhlel, I; Kilani, S; Mahmoud, A; Ghedira, K; Chekir-Ghedira, L

2007-01-01

This study evaluates genotoxic and antigenotoxic effects of extracts from leaves of Moricandia arvensis, which are used in traditional cooking and medicines. Extracts showed no genotoxicity when tested with the SOS Chromotest using E. coli PQ37 and PQ35 strains, except for the total oligomers flavonoids enriched extract. Petroleum ether and methanol extracts are the most active in reducing nitrofurantoin genotoxicity, whereas methanol and total oligomers flavonoids enriched extracts showed the most important inhibitory effect of H2O2 genotoxicity. In addition, these two extracts showed important free radical scavenging activity toward the DPPH. radical, whereas the chloroform extract exhibited the highest value of TEAC against ABTS+. radical.

In vitro Cytotoxicity and Genotoxicity Analysis of Ten Tannery Chemicals Using SOS/umu Tests and High-content In vitro Micronucleus Tests.

PubMed

Huang, Zehao; Li, Na; Rao, Kaifeng; Liu, Cuiting; Wang, Zijian; Ma, Mei

2018-01-01

More than 2,000 chemicals have been used in the tannery industry. Although some tannery chemicals have been reported to have harmful effects on both human health and the environment, only a few have been subjected to genotoxicity and cytotoxicity evaluations. This study focused on cytotoxicity and genotoxicity of ten tannery chemicals widely used in China. DNA-damaging effects were measured using the SOS/umu test with Salmonella typhimurium TA1535/pSK1002. Chromosome-damaging and cytotoxic effects were determined with the high-content in vitro Micronucleus test (MN test) using the human-derived cell lines MGC-803 and A549. The cytotoxicity of the ten tannery chemicals differed somewhat between the two cell assays, with A549 cells being more sensitive than MGC-803 cells. None of the chemicals induced DNA damage before metabolism, but one was found to have DNA-damaging effects on metabolism. Four of the chemicals, DY64, SB1, DB71 and RR120, were found to have chromosome-damaging effects. A Quantitative Structure-Activity Relationship (QSAR) analysis indicated that one structural feature favouring chemical genotoxicity, Hacceptor-path3-Hacceptor, may contribute to the chromosome-damaging effects of the four MN-test-positive chemicals. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Automated segmentation of comet assay images using Gaussian filtering and fuzzy clustering.

PubMed

Sansone, Mario; Zeni, Olga; Esposito, Giovanni

2012-05-01

Comet assay is one of the most popular tests for the detection of DNA damage at single cell level. In this study, an algorithm for comet assay analysis has been proposed, aiming to minimize user interaction and providing reproducible measurements. The algorithm comprises two-steps: (a) comet identification via Gaussian pre-filtering and morphological operators; (b) comet segmentation via fuzzy clustering. The algorithm has been evaluated using comet images from human leukocytes treated with a commonly used DNA damaging agent. A comparison of the proposed approach with a commercial system has been performed. Results show that fuzzy segmentation can increase overall sensitivity, giving benefits in bio-monitoring studies where weak genotoxic effects are expected.

Identification of formaldehyde as the metabolite responsible for the mutagenicity of methyl tertiary-butyl ether in the activated mouse lymphoma assay.

PubMed

Mackerer, C R; Angelosanto, F A; Blackburn, G R; Schreiner, C A

1996-09-01

Methyl tertiary-butyl ether (MTBE), which is added to gasoline as an octane enhancer and to reduce automotive emissions, has been evaluated in numerous toxicological tests, including those for genotoxicity. MTBE did not show any mutagenic potential in the Ames bacterial assay or any clastogenicity in cytogenetic tests. However, it has been shown to be mutagenic in an in vitro gene mutation assay using mouse lymphoma cells when tested in the presence, but not in the absence, of a rat liver-derived metabolic activation system (S-9). In the present study, MTBE was tested to determine if formaldehyde, in the presence of the S-9, was responsible for the observed mutagenicity. A modification of the mouse lymphoma assay was employed which permits determination of whether a suspect material is mutagenic because it contains or is metabolized to formaldehyde. In the modified assay, the enzyme formaldehyde dehydrogenase (FDH) and its co-factor, NAD+ are added in large excess during the exposure period so that any formaldehyde produced in the system is rapidly converted to formic acid which is not genotoxic. An MTBE dose-responsive increase in the frequency of mutants and in cytotoxicity occurred without FDH present, and this effect was greatly reduced in the presence of FDH NAD+. The findings clearly demonstrate that formaldehyde derived from MTBE is responsible for mutagenicity of MTBE in the activated mouse lymphoma assay. Furthermore, the results suggest that the lack of mutagenicity/clastogenicity seen with MTBE in other in vitro assays might have resulted from inadequacies in the test systems employed for those assays.

Mechanism-based genotoxicity screening of metal oxide nanoparticles using the ToxTracker panel of reporter cell lines.

PubMed

Karlsson, Hanna L; Gliga, Anda R; Calléja, Fabienne M G R; Gonçalves, Cátia S A G; Wallinder, Inger Odnevall; Vrieling, Harry; Fadeel, Bengt; Hendriks, Giel

2014-09-02

The rapid expansion of manufacturing and use of nano-sized materials fuels the demand for fast and reliable assays to identify their potential hazardous properties and underlying mechanisms. The ToxTracker assay is a recently developed mechanism-based reporter assay based on mouse embryonic stem (mES) cells that uses GFP-tagged biomarkers for detection of DNA damage, oxidative stress and general cellular stress upon exposure. Here, we evaluated the ability of the ToxTracker assay to identify the hazardous properties and underlying mechanisms of a panel of metal oxide- and silver nanoparticles (NPs) as well as additional non-metallic materials (diesel, carbon nanotubes and quartz). The metal oxide- and silver nanoparticles were characterized in terms of agglomeration and ion release in cell medium (using photon cross correlation spectroscopy and inductively coupled plasma with optical emission spectroscopy, respectively) as well as acellular ROS production (DCFH-DA assay). Cellular uptake was investigated by means of transmission electron microscopy. GFP reporter induction and cytotoxicity of the NPs was simultaneously determined using flow cytometry, and genotoxicity was further tested using conventional assays (comet assay, γ-H2AX and RAD51 foci formation). We show that the reporter cells were able to take up nanoparticles and, furthermore, that exposure to CuO, NiO and ZnO nanoparticles as well as to quartz resulted in activation of the oxidative stress reporter, although only at high cytotoxicity for ZnO. NiO NPs activated additionally a p53-associated cellular stress response, indicating additional reactive properties. Conventional assays for genotoxicity assessment confirmed the response observed in the ToxTracker assay. We show for CuO NPs that the induction of oxidative stress is likely the consequence of released Cu ions whereas the effect by NiO was related to the particles per se. The DNA replication stress-induced reporter, which is most strongly associated with carcinogenicity, was not activated by any of the tested nanoparticles. We conclude that the ToxTracker reporter system can be used as a rapid mechanism-based tool for the identification of hazardous properties of metal oxide NPs. Furthermore, genotoxicity of metal oxide NPs seems to occur mainly via oxidative stress rather than direct DNA binding with subsequent replication stress.

Evaluating ToxCast Assays for their Ability to Detect Genotoxicity

EPA Science Inventory

It has become evident over the past several decades, that though the standard battery of genotoxicity tests including bacterial and in vitro mammalian mutagenesis and in vitro and in vivo clastogenicity assays have been quite useful in screening out potent genotoxicants during th...

Genotoxicity and antigenotoxicity study of aqueous and hydro-methanol extracts of Spondias mombin L., Nymphaea lotus L. and Luffa cylindrical L. using animal bioassays

PubMed Central

Oyeyemi, Ifeoluwa Temitayo; Yekeen, Olaide Maruf; Odusina, Paul Olayinka; Ologun, Taiwo Mary; Ogbaide, Orezimena Michelle; Olaleye, Olayinka Israel

2015-01-01

Spondias mombin (Linn), Nymphaea lotus (Linn) and Luffa cylindrica (Linn) (syn Luffa aegyptiaca Mill) are plants traditionally used as food ingredients and in the management of diseases, including cancer, in Nigeria. Despite the therapeutic potentials attributed to these plants, reports on their genotoxicity are scanty. In this study, the genotoxicity of the aqueous and hydro-methanol extract of these plants was evaluated using mouse bone marrow micronucleus and sperm morphology assays. Antigenotoxicity was assessed by the bone marrow micronucleus test. The highest attainable dose of 5 000 mg/kg according to OECD guidelines was first used to assess acute toxicity of the aqueous and hydro-methanol extracts in Swiss albino mice. For each extract, there were five groups of mice (n=4/group) treated with different concentrations of the extract as against the negative and positive control group for the genotoxicity study. In the antigenotoxicity study, five groups of mice were exposed to five different concentrations of the extracts along with 60 mg/kg of methyl methane sulfonate (MMS), which was used to induce genotoxicity. The mice were administered 0.2 mL of extract per day for 10 days in the genotoxicity and antigenotoxicity groups. Administration of each of the extracts at the concentration of 5 000 mg/kg did not induce acute toxicity in mice. At the concentrations tested, all the extracts, except aqueous S. mombin, increased micronucleated polychromatic erythrocytes. The aqueous and hydro-methanol extracts of N. lotus increased the frequency of aberrant sperm cells. All the extracts were also able to ameliorate MMS induced genotoxicity in bone marrow cells of the exposed mice. The results showed the potential of the extracts to induce somatic and germ cell mutation in male mice. The extracts also ameliorated the genotoxic effect of MMS. PMID:27486380

Genotoxicity and antigenotoxicity study of aqueous and hydro-methanol extracts of Spondias mombin L., Nymphaea lotus L. and Luffa cylindrical L. using animal bioassays.

PubMed

Oyeyemi, Ifeoluwa Temitayo; Yekeen, Olaide Maruf; Odusina, Paul Olayinka; Ologun, Taiwo Mary; Ogbaide, Orezimena Michelle; Olaleye, Olayinka Israel; Bakare, Adekunle A

2015-12-01

Spondias mombin (Linn), Nymphaea lotus (Linn) and Luffa cylindrica (Linn) (syn Luffa aegyptiaca Mill) are plants traditionally used as food ingredients and in the management of diseases, including cancer, in Nigeria. Despite the therapeutic potentials attributed to these plants, reports on their genotoxicity are scanty. In this study, the genotoxicity of the aqueous and hydro-methanol extract of these plants was evaluated using mouse bone marrow micronucleus and sperm morphology assays. Antigenotoxicity was assessed by the bone marrow micronucleus test. The highest attainable dose of 5 000 mg/kg according to OECD guidelines was first used to assess acute toxicity of the aqueous and hydro-methanol extracts in Swiss albino mice. For each extract, there were five groups of mice (n=4/group) treated with different concentrations of the extract as against the negative and positive control group for the genotoxicity study. In the antigenotoxicity study, five groups of mice were exposed to five different concentrations of the extracts along with 60 mg/kg of methyl methane sulfonate (MMS), which was used to induce genotoxicity. The mice were administered 0.2 mL of extract per day for 10 days in the genotoxicity and antigenotoxicity groups. Administration of each of the extracts at the concentration of 5 000 mg/kg did not induce acute toxicity in mice. At the concentrations tested, all the extracts, except aqueous S. mombin, increased micronucleated polychromatic erythrocytes. The aqueous and hydro-methanol extracts of N. lotus increased the frequency of aberrant sperm cells. All the extracts were also able to ameliorate MMS induced genotoxicity in bone marrow cells of the exposed mice. The results showed the potential of the extracts to induce somatic and germ cell mutation in male mice. The extracts also ameliorated the genotoxic effect of MMS.

Genotoxic potential evaluation of a cosmetic insoluble substance by the micronuclei assay.

PubMed

Dayan, N; Shah, V; Minko, T

2011-01-01

An optical brightener (OB) powder (INCI: sodium silicoaluminate (and) glycidoxypropyl trimethyloxysilane/PEI-250 cross fluorescent brightener 230 salt (and) polyvinylalcohol crosspolymer) that is used in cosmetic facial products was tested for its genotoxic potential using the micronuclei test (MNT). It is a solid dry powder with an average size of 5 microns that is insoluble but dispersible in water. This study describes the exposure of cell culture to positive controls with and without enzymatic activation and to the test compound in different concentrations. We evaluated three end points: microscopic observation and quantification of micronuclei formation, and cell viability and proliferation. Both positive controls induced significant changes that were observed under the microscope and quantified. Based on its chemical nature, it was not anticipated that the test substance will degrade under the conditions of the experiments. However, the test is required to make sure that when solublized, impurities that may be present, even at trace levels, will not induce a genotoxic effect. The test compound did not promote micronuclei formation or change the viability or proliferation rate of cells. During this study we faced challenges such as solubilization and correlating viability data to genotoxicity data. These are described in the body of the paper. We believe that with the emergence of the 7(th) European amendment that bans animal testing, sharing these data and the study protocol serves as a key in building the understanding of the utilization of in vitro studies in the safety assessment of cosmetic ingredients.

Intestinal bacteria modify lymphoma incidence and latency by affecting systemic inflammatory state, oxidative stress, and leucocyte genotoxicity

PubMed Central

Yamamoto, Mitsuko L.; Maier, Irene; Dang, Angeline Tilly; Berry, David; Liu, Jared; Ruegger, Paul M.; Yang, Jiue-in; Soto, Phillip A.; Presley, Laura L.; Reliene, Ramune; Westbrook, Aya M.; Wei, Bo; Loy, Alexander; Chang, Christopher; Braun, Jonathan; Borneman, James; Schiestl, Robert H.

2013-01-01

Ataxia-telangiectasia (A-T) is a genetic disorder associated with high incidence of B cell lymphoma. Using an A-T mouse model, we compared lymphoma incidence in several isogenic mouse colonies harboring different bacterial communities, finding that intestinal microbiota are a major contributor to disease penetrance and latency, lifespan, molecular oxidative stress and systemic leucocyte genotoxicity. High throughput sequence analysis of rRNA genes identified mucosa-associated bacterial phylotypes that were colony-specific. Lactobacillus johnsonii, which was deficient in the more cancer-prone mouse colony, was causally tested for its capacity to confer reduced genotoxicity when restored by short-term oral transfer. This intervention decreased systemic genotoxicity, a response associated with reduced basal leucocytes and the cytokine-mediated inflammatory state, and mechanistically linked to the host cell biology of systemic genotoxicity. Our results suggest that intestinal microbiota are a potentially modifiable trait for translational intervention in individuals at risk for B cell lymphoma, or for other diseases that are driven by genotoxicity or the molecular response to oxidative stress. PMID:23860718

Protective Effects of Quercetin against Dimethoate-Induced Cytotoxicity and Genotoxicity in Allium sativum Test

PubMed Central

Ahmad, Waseem; Shaikh, Sibhghatulla; Nazam, Nazia; Lone, Mohammad Iqbal

2014-01-01

The present investigation was directed to study the possible protective activity of quercetin—a natural antioxidant against dimethoate-induced cyto- and genotoxicity in meristematic cells of Allium sativum. So far there is no report on the biological properties of quercetin in plant test systems. Chromosome breaks, multipolar anaphase, stick chromosome, and mitotic activity were undertaken in the current study as markers of cyto- and genotoxicity. Untreated control, quercetin controls (@ 5, 10 and 20 μg/mL for 3 h), and dimethoate exposed groups (@ 100 and 200 μg/mL for 3 h) were maintained. For protection against cytogenotoxicity, the root tip cells treated with dimethoate at 100 and 200 μg/mL for 3 h and quercetin treatment at 5, 10, and 20 μg/mL for 16 h, prior to dimethoate treatment, were undertaken. Quercetin was found to be neither cytotoxic nor genotoxic in Allium sativum control at these doses. A significant increase (P < 0.05) in chromosomal aberrations was noted in dimethoate treated Allium. Pretreatment of Allium sativum with quercetin significantly (P < 0.05) reduced dimethoate-induced genotoxicity and cytotoxicity in meristematic cells, and these effects were dose dependent. In conclusion, quercetin has a protective role in the abatement of dimethoate-induced cyto- and genotoxicity in the meristematic cells of Allium sativum that resides, at least in part, on its antioxidant effects. PMID:27379342

Protective Effects of Quercetin against Dimethoate-Induced Cytotoxicity and Genotoxicity in Allium sativum Test.

PubMed

Ahmad, Waseem; Shaikh, Sibhghatulla; Nazam, Nazia; Lone, Mohammad Iqbal

2014-01-01

The present investigation was directed to study the possible protective activity of quercetin-a natural antioxidant against dimethoate-induced cyto- and genotoxicity in meristematic cells of Allium sativum. So far there is no report on the biological properties of quercetin in plant test systems. Chromosome breaks, multipolar anaphase, stick chromosome, and mitotic activity were undertaken in the current study as markers of cyto- and genotoxicity. Untreated control, quercetin controls (@ 5, 10 and 20 μg/mL for 3 h), and dimethoate exposed groups (@ 100 and 200 μg/mL for 3 h) were maintained. For protection against cytogenotoxicity, the root tip cells treated with dimethoate at 100 and 200 μg/mL for 3 h and quercetin treatment at 5, 10, and 20 μg/mL for 16 h, prior to dimethoate treatment, were undertaken. Quercetin was found to be neither cytotoxic nor genotoxic in Allium sativum control at these doses. A significant increase (P < 0.05) in chromosomal aberrations was noted in dimethoate treated Allium. Pretreatment of Allium sativum with quercetin significantly (P < 0.05) reduced dimethoate-induced genotoxicity and cytotoxicity in meristematic cells, and these effects were dose dependent. In conclusion, quercetin has a protective role in the abatement of dimethoate-induced cyto- and genotoxicity in the meristematic cells of Allium sativum that resides, at least in part, on its antioxidant effects.

Environmental nitration processes enhance the mutagenic potency of aromatic compounds.

PubMed

Bonnefoy, Aurélie; Chiron, Serge; Botta, Alain

2012-05-01

This work is an attempt to establish if aromatic nitration processes are always associated with an increase of genotoxicity. We determined the mutagenic and genotoxic effects of Benzene (B), Nitrobenzene (NB), Phenol (P), 2-Nitrophenol (2-NP), 2,4-Dinitrophenol (2,4-DNP), Pyrene (Py), 1-Nitropyrene (1-NPy), 1,3-Dinitropyrene (1,3-DNPy), 1,6-Dinitropyrene (1,6-DNPy), and 1,8-Dinitropyrene (1,8-DNPy). The mutagenic activities were evaluated with umuC test in presence and in absence of metabolic activation with S9 mix. Then, we used both cytokinesis-blocked micronucleus (CBMN) assay, in combination with fluorescent in situ hybridization (FISH) of human pan-centromeric DNA probes on human lymphocytes in order to evaluate the genotoxic effects. Analysis of all results shows that nitro polycyclic aromatic hydrocarbons (PAHs) are definitely environmental genotoxic/mutagenic hazards and confirms that environmental aromatic nitration reactions lead to an increase in genotoxicity and mutagenicity properties. Particularly 1-NPy and 1,8-DNPy can be considered as human potential carcinogens. They seem to be significant markers of the genotoxicity, mutagenicity, and potential carcinogenicity of complex PAHs mixtures present in traffic emission and industrial environment. In prevention of environmental carcinogenic risk 1-NPy and 1,8-DNPy must therefore be systematically analyzed in environmental complex mixtures in association with combined umuC test, CBMN assay, and FISH on cultured human lymphocytes. © 2010 Wiley Periodicals, Inc. Environ Toxicol, 2012. Copyright © 2010 Wiley Periodicals, Inc.

Genotoxicity in native fish associated with agricultural runoff events

USGS Publications Warehouse

Whitehead, Andrew; Kuivila, Kathryn; Orlando, James L.; Kotelevtsev, S.; Anderson, Susan L.

2004-01-01

The primary objective of the present study was to test whether agricultural chemical runoff was associated with in-stream genotoxicity in native fish. Using Sacramento sucker (Catostomus occidentalis), we combined field-caging experiments in an agriculturally dominated watershed with controlled laboratory exposures to field-collected water samples, and we coupled genotoxicity biomarker measurements in fish with bacterial mutagenicity analysis of water samples. We selected DNA strand breakage as a genotoxicity biomarker and Ames Salmonella mutagenicity tests as a second, supporting indicator of genotoxicity. Data from experiments conducted during rainfall runoff events following winter application of pesticides in 2000 and 2001 indicated that DNA strand breaks were significantly elevated in fish exposed to San Joaquin River (CA, USA) water (38.8, 28.4, and 53.6% DNA strand breakage in year 2000 field, year 2000 lab, and year 2001 field exposures, respectively) compared with a nearby reference site (15.4, 8.7, and 12.6% DNA strand breakage in year 2000 field, year 2000 lab, and year 2001 field exposures, respectively). Time-course measurements in field experiments supported a linkage between induction of DNA strand breakage and the timing of agricultural runoff. San Joaquin River water also caused significant reversion mutation in two Ames Salmonella tester strains. Salmonella mutagenicity corroborated in-stream effects, further strengthening a causal relationship between runoff events and genotoxicity. Potentially responsible agents are discussed in the context of timing of runoff events in the field, concordance between laboratory and field exposures, pesticide application patterns in the drainage, and analytical chemistry data.

Genotoxicity assessment of propyl thiosulfinate oxide, an organosulfur compound from Allium extract, intended to food active packaging.

PubMed

Mellado-García, P; Maisanaba, S; Puerto, M; Llana-Ruiz-Cabello, M; Prieto, A I; Marcos, R; Pichardo, S; Cameán, A M

2015-12-01

Essential oils from onion (Allium cepa L.), garlic (Allium sativum L.), and their main components, such as propyl thiosulfinate oxide (PTSO) are being intended for active packaging with the purpose of maintaining and extending food product quality and shelf life. The present work aims to assess for the first time the potential mutagenicity/genotoxicity of PTSO (0-50 µM) using the following battery of genotoxicity tests: (1) the bacterial reverse-mutation assay in Salmonella typhimurium (Ames test, OECD 471); (2) the micronucleus test (OECD 487) (MN) and (3) the mouse lymphoma thymidine-kinase assay (OECD 476) (MLA) on L5178YTk(+/-), cells; and (4) the comet assay (with and without Endo III and FPG enzymes) on Caco-2 cells. The results revealed that PTSO was not mutagenic in the Ames test, however it was mutagenic in the MLA assay after 24 h of treatment (2.5-20 µM). The parent compound did not induce MN on mammalian cells; however, its metabolites (in the presence S9) produced positive results (from 15 µM). Data from the comet assay indicated that PTSO did not induce DNA breaks or oxidative DNA damage. Further in vivo genotoxicity tests are needed to confirm its safety before it is used as active additive in food packaging. Copyright © 2015 Elsevier Ltd. All rights reserved.

Genotoxicity evaluation of two metallic-insecticides using Allium cepa and Tradescantia pallida: A new alternative against leaf-cutting ants.

PubMed

de Souza, Raphael Bastão; de Souza, Cleiton Pereira; Bueno, Odair Correa; Fontanetti, Carmem Silvia

2017-02-01

In order to combat leaf-cutting ants, the pesticide sulfluramid used to be the most widely utilized active ingredient. However, its use was banned in 2009 by the Stockholm Convention, although some countries were allowed to continue using it. As an effective alternative to its replacement, researchers developed a metallic-insecticide system, which is a natural product linked to metal complexes. Thus, the aim of this study was to evaluate the ability of these new metallic-insecticides in change the genetic material of non-target organisms. The tests were performed utilizing chromosomal aberrations and micronucleus tests in the Allium cepa test system and the Trad-MCN test in Tradescantia pallida. To better understand the results, one of the components of the formula, 5-methyl-phenanthroline, was also analyzed according to the same parameters. To A. cepa, the results showed that one of the metallic insecticides induced cytotoxicity and genotoxicity at different concentrations, while the other metallic-insecticide showed chromosomal instability only at the highest concentration. The analysis of 5-methyl-phenanthroline revealed that it can be related with the positive results, since genotoxic effects were induced. In the Trad-MCN test, none of the metallic-insecticides showed genotoxic activity, although one of them induced more micronucleus formation. Copyright © 2016 Elsevier Ltd. All rights reserved.

Genotoxicity assessment of some cosmetic and food additives.

PubMed

Di Sotto, Antonella; Maffei, Francesca; Hrelia, Patrizia; Di Giacomo, Silvia; Pagano, Ester; Borrelli, Francesca; Mazzanti, Gabriela

2014-02-01

α-Hexylcinnamaldehyde (HCA) and p-tert-butyl-alpha-methylhydrocinnamic aldehyde (BMHCA) are synthetic aldehydes, characterized by a typical floral scent, which makes them suitable to be used as fragrances in personal care (perfumes, creams, shampoos, etc.) and household products, and as flavouring additives in food and pharmaceutical industry. The aldehydic structure suggests the need for a safety assessment for these compounds. Here, HCA and BMHCA were evaluated for their potential genotoxic risk, both at gene level (frameshift or base-substitution mutations) by the bacterial reverse mutation assay (Ames test), and at chromosomal level (clastogenicity and aneuploidy) by the micronucleus test. In order to evaluate a primary and repairable DNA damage, the comet assay has been also included. In spite of their potential hazardous chemical structure, a lack of mutagenicity was observed for both compounds in all bacterial strains tested, also in presence of the exogenous metabolic activator, showing that no genotoxic derivatives were produced by CYP450-mediated biotransformations. Neither genotoxicity at chromosomal level (i.e. clastogenicity or aneuploidy) nor single-strand breaks were observed. These findings will be useful in further assessing the safety of HCA and BMHCA as either flavour or fragrance chemicals. Copyright © 2013 Elsevier Inc. All rights reserved.

Chemical characterization and cytotoxic, genotoxic, and mutagenic properties of Baccharis trinervis (Lam, Persoon) from Colombia and Brazil.

PubMed

Jaramillo-García, Victoria; Trindade, Cristiano; Lima, Elisiane; Guecheva, Temenouga N; Villela, Izabel; Martinez-Lopez, Wilner; Corrêa, Dione S; Ferraz, Alexandre de B F; Moura, Sidnei; Sosa, Milton Quintana; Da Silva, Juliana; Henriques, João Antônio Pegas

2018-03-01

Baccharis trinervis (Lam, Persoon) leaves are used in the traditional medicine for the treatment of high fevers, edema, inflammation, sores and muscle cramps, snakebites and as antiseptic. To investigate the cytotoxic, genotoxic, and mutagenic effects of extracts and fractions of B. trinervis from Brazil and Colombia in Chinese Hamster Ovary (CHO) cells, and to examine the mutagenic activity in Salmonella typhimurium. Aqueous extracts (AE) of aerial parts of B. trinervis from Brazil (B) and Colombia (C) were fractioned in ethyl acetate fraction (EAF), butanol extract (BF), and aqueous residue fraction (ARF). Qualitative chemical screening and determination of total flavonoid content were made. Identification of chemical constituents was performed by High Performance Liquid Chromatography (HPLC) and High Resolution Mass Spectrometry (HRMS). For the in vitro tests, CHO cells were treated for 3h with extracts and fractions. The cytotoxic activity was evaluated by clonal survival and 3-(4.5-dimethylthiazole-2-yl)-2.5-biphenyl tetrazolium bromide reduction assay (MTT). Genotoxic and mutagenic effects were evaluated by the alkaline comet assay and Cytokinesis-blockage micronucleus test (CBMN), respectively. Additionally, Salmonella/microsome assay was carried out to determinate the mutagenic effects in EAF from Brazil and Colombia. Phytochemical analyses indicated the presence of saponins and flavonoids. AE and EAF were the samples with the highest quantity of total flavonoids. HPLC showed the presence of luteolin only in AEC, and caffeic acid, ellagic acid, rosmarinic acid, and rutin were identified in AEB and AEC (AEC>AEB). The HRMS in positive mode of EAFB and EAFC showed presence of two carboxylic acids, coumarin, and two terpenoids. In addition, were identified one terpenoid and two carboxylic acids in AE, BF and ARF of B. trinervis from both countries in negative mode. Dose-dependent cytotoxic effects were observed in CHO cells treated with B. trinervis extracts and fractions by using clonal survival and MTT at concentrations higher than 0.05mg/mL. All the extracts and fractions induced DNA strand breaks in CHO cells with dose-dependent response, mostly EAFB and EAFC. The EAF from Brazil and Colombia showed mutagenic effect at 0.5mg/mL, while the other fractions did not show a significant difference in relation to the control. No mutagenic effects were found in EAF from both countries by the Salmonella/microsome assay. Cytotoxic and genotoxic effects were demonstrated in all extracts and fractions used, although only EAF showed mutagenic effects by CBMN, but not by Salmonella/microsome assay. Our results suggest that flavonoids, phenylpropanoids, coumarins, and diterpenes may be responsible for the cytotoxic, genotoxic and mutagenic effects observed. Copyright © 2017 Elsevier B.V. All rights reserved.

Genotoxicity of air borne particulates assessed by comet and the Salmonella mutagenicity test in Jeddah, Saudi Arabia.

PubMed

Elassouli, Sufian M; Alqahtani, Mohamed H; Milaat, Waleed

2007-09-01

Fine airborne respirable particulates less than 10 micrometer (PM10) are considered one of the top environmental public health concerns, since they contain polycyclic aromatic hydrocarbons (PAHs) which are among the major carcinogenic compounds found in urban air. The objective of this study is to assess the genotoxicity of the ambient PM10 collected at 11 urban sites in Jeddah, Saudi Arabia. The PM10 extractable organic matter (EOM) was examined for its genotoxicity by the single cell gel electrophoresis (SCGE) comet assay and the Salmonella mutagenicity (Ames) test .Gas chromatography-mass spectrometry was used to quantify 16 PAH compounds in four sites. Samples from oil refinery and heavy diesel vehicles traffic sites showed significant DNA damage causing comet in 20-44% of the cells with tail moments ranging from 0.5-2.0 compared to samples from petrol driven cars and residential area, with comet in less than 2% of the cells and tail moments of < 0.02. In the Ames test, polluted sites showed indirect mutagenic response and caused 20-56 rev/ m3, mean while residential and reference sites caused 2-15 rev /m3. The genotoxicity of the EOM in both tests directly correlated with the amount of organic particulate and the PAHs concentrations in the air samples. The PAHs concentrations ranged between 0.83 ng/m3 in industrial and heavy diesel vehicles traffic sites to 0.18 ng /m3 in the residential area. Benzo(ghi)pyrene was the major PAH components and at one site it represented 65.4 % of the total PAHs. Samples of the oil refinery site were more genotoxic in the SCGE assay than samples from the heavy diesel vehicles traffic site, despite the fact that both sites contain almost similar amount of PAHs. The opposite was true for the mutagenicity in the Ames test. This could be due to the nature of the EOM in both sites. These findings confirm the genotoxic potency of the PM10 organic extracts to which urban populations are exposed.

Intermediate frequency magnetic field generated by a wireless power transmission device does not cause genotoxicity in vitro.

PubMed

Shi, Dejing; Zhu, Chunbo; Lu, Rengui; Mao, Shitong; Qi, Yanhua

2014-10-01

The aim of this study was to evaluate effects of intermediate frequency magnetic fields (IFMF) generated by a wireless power transmission (WPT) based on magnetic resonance from the perspective of cellular genotoxicity on cultured human lens epithelial cells (HLECs). We evaluated the effects of exposure to 90 kHz magnetic fields at 93.36 µT on cellular genotoxicity in vitro for 2 and 4 h. The magnetic flux density is approximately 3.5 times higher than the reference level recommended by the International Commission on Non-Ionizing Radiation Protection (ICNIRP) guidelines. For assessment of genotoxicity, we studied cellular proliferation, apoptosis and DNA damage by Cell Counting Kit-8 (CCK-8) assay, flow cytometry analysis, alkaline comet assay and phosphorylated histone H2AX (γH2AX) foci formation test. We did not detect any effect of a 90 kHz IFMF generated by WPT based on magnetic resonance on cell proliferation, apoptosis, comet assay, and γH2AX foci formation test. Our results indicated that exposure to 90 kHz IFMF generated by WPT based on magnetic resonance at 93.36 µT for 2 and 4 h does not cause detectable cellular genotoxicity. © 2014 Wiley Periodicals, Inc.

Synergistic effect of Gentiana lutea L. on methyl methanesulfonate genotoxicity in the Drosophila wing spot test.

PubMed

Patenković, Aleksandra; Stamenković-Radak, Marina; Nikolić, Dragana; Marković, Tamara; Anđelković, Marko

2013-03-27

Gentiana lutea L., the yellow gentian, is herb known for its pharmacological properties, with a long tradition of use for the treatment of a variety of diseases including the use as a remedy for digestion, also in food products and in bitter beverages. The aim of the present study is to evaluate, for the first time, genotoxicity of gentian alone, and its antigenotoxicity against methyl methanesulfonate (MMS). The water infusion of the underground part of gentian were evaluated in vivo using the Drosophila wing spot test, at the dose commonly used in traditional medicine. For antigenotoxic study two types of treatment with gentian and MMS were performed: chronic co-treatment, as well as post-treatment with gentian after acute exposure with MMS. Water infusion of gentian alone did not exhibit genotoxicity. The results of co- and post-treatment experiments with gentian show that gentian enhanced the frequency of mutant clones over the values obtained with MMS alone, instead of reducing the genotoxicity of MMS, for 22.64% and 27.13% respectively. This result suggests a synergism of gentian with MMS, and indicates that water infusion of gentian used in traditional medicine may have particular effects with regard to genotoxicity indicating careful use. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Cytotoxicity and genotoxicity of natural resin-based experimental endodontic sealers.

PubMed

Silva, Gleyce O; Cavalcanti, Bruno N; Oliveira, Tatiana R; Bin, Claudia V; Camargo, Samira E A; Camargo, Carlos H R

2016-05-01

The development of endodontic sealers based on natural resins seems to be promising, given their improved biological properties. This study evaluated the cytotoxic and genotoxic effects of two experimental root canal sealers, based on extracts from Copaifera multijuga and Ricinus communis (castor oil polymer), comparing them to synthetic resin-based sealers: a single methacrylate-based, a multi-methacrylate-based, and an epoxy resin-based sealers. Sealers were prepared, set, and exposed to cell culture medium for 24 h at 37 °C with CO2. V79 cells were exposed to serial dilutions of the extracts of each sealer for 24 h. Cell viability was measured by the MTT assay and genotoxicity was assessed by the formation of micronuclei. The single methacrylate-based sealer had the most cytotoxic effects, with significant reduction in cell viability in all dilutions of the extract. The castor oil polymer-based sealer was, on the other hand, the most biocompatible sealer, with no cytotoxic effects at any concentration. All tested sealers were not genotoxic, excepting the single methacrylate-based sealer. The tested natural resin-based sealers presented low cytotoxic and no genotoxic effects on cell cultures. These results may suggest a good alternative to develop new endodontic sealers, in order to achieve better biological response and healing, when compared to commercially available sealers.

Genotoxicity studies of organically grown broccoli (Brassica oleracea var. italica) and its interactions with urethane, methyl methanesulfonate and 4-nitroquinoline-1-oxide genotoxicity in the wing spot test of Drosophila melanogaster.

PubMed

Heres-Pulido, María Eugenia; Dueñas-García, Irma; Castañeda-Partida, Laura; Santos-Cruz, Luis Felipe; Vega-Contreras, Viridiana; Rebollar-Vega, Rosa; Gómez-Luna, Juan Carlos; Durán-Díaz, Angel

2010-01-01

Broccoli (Brassica oleracea var. italica) has been defined as a cancer preventive food. Nevertheless, broccoli contains potentially genotoxic compounds as well. We performed the wing spot test of Drosophila melanogaster in treatments with organically grown broccoli (OGB) and co-treatments with the promutagen urethane (URE), the direct alkylating agent methyl methanesulfonate (MMS) and the carcinogen 4-nitroquinoline-1-oxide (4-NQO) in the standard (ST) and high bioactivation (HB) crosses with inducible and high levels of cytochrome P450s (CYPs), respectively. Larvae of both crosses were chronically fed with OGB or fresh market broccoli (FMB) as a non-organically grown control, added with solvents or mutagens solutions. In both crosses, the OGB added with Tween-ethanol yielded the expected reduction in the genotoxicity spontaneous rate. OGB co-treatments did not affect the URE effect, MMS showed synergy and 4-NQO damage was modulated in both crosses. In contrast, FMB controls produced damage increase; co-treatments modulated URE genotoxicity, diminished MMS damage, and did not change the 4-NQO damage. The high dietary consumption of both types of broccoli and its protective effects in D. melanogaster are discussed. Copyright 2009 Elsevier Ltd. All rights reserved.

Nonclinical Safety Assessment of Morus alba L. Fruits: Study of 90-D Toxicity in Sprague Dawley Rats and Genotoxicity in Salmonella.

PubMed

Chang, Bo Yoon; Kim, Seon Beom; Lee, Mi Kyeong; Park, Hyun; Kim, Sung Yeon

2016-05-01

Morus alba L. is a traditional herb with a long history of consumption, both as an edible fruit and as medicine. However, its safety evaluation has not yet been established. The objective of this study was to evaluate subchronic oral toxicity and genotoxicity of M. alba L. fruits (MFE). The subchronic toxicity after daily oral administration of MFE at 0, 40, 200, and 1000 mg/kg for 90 d was examined in Sprague Dawley (SD) rats. MFE administration did not lead to death, adverse effects, change in food and water consumption, and body weight gain. Significant toxic effects were not found within the parameters of organ weight, biochemical values, and hematological and urine analysis between the control and the MFE group. The genotoxicity of MFE was assayed by Ames test in Salmonella typhimurium strains TA98, TA102, and TA1535. No genotoxicity was found in all the tested strains. Thus in this study, a no-observed-adverse-effect level for MFE in 90 d repeated oral toxicity study in rats was determined to be greater than 1000 mg/kg regardless of gender. The results also suggested that MFE does not have a genotoxicity potential. © 2016 Institute of Food Technologists®

Genotoxicity of Swimming Pool Water and Carcinogenicity of Drinking Water

EPA Science Inventory

Among the 11 disinfection by-products (DBPs) in drinking water that are regulated by the U.S. EPA, (a) 2 DBPs (chloroaceticacid and chlorite) are not carcinogenic-in either of2 species; (b) chlorite is not carcinogenic in 3 rodent assays and has never been tested for genotoxicity...

Genotoxicity of Swimming Pool Water and Carcinogenicity of Drinking Water**

EPA Science Inventory

Among the 11 disinfection by-products (DBPs) in drinking water that are regulated by the U.S. EPA, (a) 2 DBPs (chloroaceticacid and chlorite) are not carcinogenic-in either of2 species; (b) chlorite is not carcinogenic in 3 rodent assays and has never been tested for genotoxicity...

Sister-chromatid exchanges and cell-cycle kinetics in the lymphocytes of workers occupationally exposed to a chemical mixture in the tyre industry.

PubMed

Sasiadek, M

1993-08-01

Cytogenetic studies of clinically healthy workers employed in the rubber industry showed an increase in chromosome aberrations (CAs), sister-chromatid exchanges (SCEs) and a decrease in proliferation indices (PIs). The aim of the present study was to establish, using the SCE and PI tests, genotoxic effects of hazardous chemicals in the rubber industry. An increase in mean SCEs in the lymphocytes of vulcanizers as compared to controls was observed. Since the PI in the exposed group was insignificantly decreased as compared to the controls, it could be concluded that the SCE test is the most sensitive cytogenetic test for the detection of a genotoxic effect of chemicals in the rubber industry. There was no evidence in the present study that the genotoxic effect of chemicals in the rubber industry was enhanced by cigarette smoking.

Cell-Based Genotoxicity Testing

NASA Astrophysics Data System (ADS)

Reifferscheid, Georg; Buchinger, Sebastian

Genotoxicity test systems that are based on bacteria display an important role in the detection and assessment of DNA damaging chemicals. They belong to the basic line of test systems due to their easy realization, rapidness, broad applicability, high sensitivity and good reproducibility. Since the development of the Salmonella microsomal mutagenicity assay by Ames and coworkers in the early 1970s, significant development in bacterial genotoxicity assays was achieved and is still a subject matter of research. The basic principle of the mutagenicity assay is a reversion of a growth inhibited bacterial strain, e.g., due to auxotrophy, back to a fast growing phenotype (regain of prototrophy). Deeper knowledge of the ­mutation events allows a mechanistic understanding of the induced DNA-damage by the utilization of base specific tester strains. Collections of such specific tester strains were extended by genetic engineering. Beside the reversion assays, test systems utilizing the bacterial SOS-response were invented. These methods are based on the fusion of various SOS-responsive promoters with a broad variety of reporter genes facilitating numerous methods of signal detection. A very important aspect of genotoxicity testing is the bioactivation of ­xenobiotics to DNA-damaging compounds. Most widely used is the extracellular metabolic activation by making use of rodent liver homogenates. Again, genetic engineering allows the construction of highly sophisticated bacterial tester strains with significantly enhanced sensitivity due to overexpression of enzymes that are involved in the metabolism of xenobiotics. This provides mechanistic insights into the toxification and detoxification pathways of xenobiotics and helps explaining the chemical nature of hazardous substances in unknown mixtures. In summary, beginning with "natural" tester strains the rational design of bacteria led to highly specific and sensitive tools for a rapid, reliable and cost effective ­genotoxicity testing that is of outstanding importance in the risk assessment of compounds (REACH) and in ecotoxicology.

A battery of in vivo and in vitro tests useful for genotoxic pollutant detection in surface waters.

PubMed

Pellacani, Claudia; Buschini, Annamaria; Furlini, Mariangela; Poli, Paola; Rossi, Carlo

2006-04-20

Since the 1980s, stricter water quality regulations have been promulgated in many countries throughout the world. We discuss the application of a battery of both in vivo and in vitro genotoxicity tests on lake water as a tool for a more complete assessment of surface water quality. The lake water concentrated by adsorption on C18 silica cartridges were used for the following in vitro biological assays: gene conversion, point mutation, mitochondrial DNA mutability assays on the diploid Saccharomyces cerevisiae D7 strain, with or without endogenous P450 complex induction; DNA damage on fresh human leukocytes by the comet. Toxicity testing on yeast and human cells was also performed. In vivo genotoxicity was determined by the comet assay on two well-established bio-indicator organisms of water quality (Cyprinus carpio erythrocytes and Dreissena polymorpha haemocytes) exposed in situ. The in vivo experiments and the water samplings were carried out during different campaigns to detect seasonal variations of both the water contents and physiological state of the animals. Temperature and oxygen level seasonal variations and different pollutant contents in the lake water appeared to affect the DNA migration in carp and zebra mussel cells. Seasonal variability of lake water quality was also evident in the in vitro genotoxicity and cytotoxicity tests, with regards to water pollutant quantity and quality (direct-acting compounds or indirect-acting compounds on yeast cells). However, the measured biological effects did not appear clearly related to the physical-chemical characteristics of lake waters. Therefore, together with the conventional chemical analysis, mutagenicity/genotoxicity assays should be included as additional parameters in water quality monitoring programs: their use could permit the quantification of mutagenic hazard in surface waters.

Correlation of In Vivo Versus In Vitro Benchmark Doses (BMDs) Derived From Micronucleus Test Data: A Proof of Concept Study.

PubMed

Soeteman-Hernández, Lya G; Fellows, Mick D; Johnson, George E; Slob, Wout

2015-12-01

In this study, we explored the applicability of using in vitro micronucleus (MN) data from human lymphoblastoid TK6 cells to derive in vivo genotoxicity potency information. Nineteen chemicals covering a broad spectrum of genotoxic modes of action were tested in an in vitro MN test using TK6 cells using the same study protocol. Several of these chemicals were considered to need metabolic activation, and these were administered in the presence of S9. The Benchmark dose (BMD) approach was applied using the dose-response modeling program PROAST to estimate the genotoxic potency from the in vitro data. The resulting in vitro BMDs were compared with previously derived BMDs from in vivo MN and carcinogenicity studies. A proportional correlation was observed between the BMDs from the in vitro MN and the BMDs from the in vivo MN assays. Further, a clear correlation was found between the BMDs from in vitro MN and the associated BMDs for malignant tumors. Although these results are based on only 19 compounds, they show that genotoxicity potencies estimated from in vitro tests may result in useful information regarding in vivo genotoxic potency, as well as expected cancer potency. Extension of the number of compounds and further investigation of metabolic activation (S9) and of other toxicokinetic factors would be needed to validate our initial conclusions. However, this initial work suggests that this approach could be used for in vitro to in vivo extrapolations which would support the reduction of animals used in research (3Rs: replacement, reduction, and refinement). © The Author 2015. Published by Oxford University Press on behalf of the Society of Toxicology.

DNA Damage Potential of Engine Emissions Measured In Vitro by Micronucleus Test in Human Bronchial Epithelial Cells.

PubMed

Cervena, Tereza; Rossnerova, Andrea; Sikorova, Jitka; Beranek, Vit; Vojtisek-Lom, Michal; Ciganek, Miroslav; Topinka, Jan; Rossner, Pavel

2017-09-01

Internal combustion engine emissions belong among the major anthropogenic sources of air pollution in urban areas. According to the International Agency for Research on Cancer, there is sufficient evidence of the carcinogenicity of diesel exhaust in human beings. Although alternative fuels, mainly biodiesel, have recently become popular, little is still known about the genotoxicity of emissions from these fuels. We analysed DNA damage expressed as the frequency of micronuclei (MN) in human bronchial epithelial cells (BEAS-2B), induced by extractable organic matter (EOM; tested concentrations: 1, 10 and 25 μg/ml) obtained from particle emissions from various blends of biodiesel with diesel fuels (including neat diesel fuel (B0), a blend of 70% B0 and 30% biodiesel (B30) and neat biodiesel (B100)). We also tested the effect of selected diesel exhaust organic/genotoxic components [benzo[a]pyrene (B[a]P) concentrations: 25, 100 and 200 μM; 1-nitropyrene (1-NP) concentrations: 1, 5 and 10 μM; 3-nitrobenzanthrone (3-NBA) concentrations: 1, 5 and 50 μM]. The cells were treated with the compounds for 28 and 48 hr. Our results showed that most of the tested compounds (except for the 25 μM B[a]P, 28-hr treatment) significantly increased MN frequency. The genotoxicity of EOMs from the engine emissions of diesel and biodiesel engines was comparable. Both nitro-PAH compounds demonstrated higher genotoxic potential in comparison with B[a]P. Considering our results and due to increasing popularity of alternative fuels, it is prudent that the potential genotoxic effects of various fuels are investigated across engine technologies and operating conditions in a relevant model system. © 2016 Nordic Association for the Publication of BCPT (former Nordic Pharmacological Society).

Evaluation of genotoxic and antigenotoxic effects of hydroalcoholic extracts of Zuccagnia punctata Cav.

PubMed

Zampini, Iris Catiana; Villarini, Milena; Moretti, Massimo; Dominici, Luca; Isla, María Inés

2008-01-17

Zuccagnia punctata Cav. (Fabaceae), a widely used plant species in Argentine folk medicine, has been shown to have a broad spectrum of antibacterial, antifungal, antioxidant and cytoprotective activities. In this study, the hydroalcoholic extract of Zuccagnia punctata and 2',4'-dihydroxychalcone isolated from it were investigated for genotoxicity/antigenotoxicity in the in vitro comet assay test on human hepatoma HepG2 cells. No acute toxicity of the extract could be determined. HepG2 cells were treated with three different concentrations (2.5, 5.0 and 10.0 microg/mL) or 2',4'-dihydroxychalcone (0.01, 0.10 and 1.00 microg/mL). To explore the potential mechanisms of action, two approaches were followed: co-treatment with 4-nitroquinoline-N-oxyde (4-NQO), a direct genotoxic compound, and a pre-treatment protocol with benzo[a]pyrene (B[a]P), an indirect genotoxic compound. The natural products neither affected cell viability nor induced DNA damage in the concentration range tested. Zuccagnia punctata tinctures were able to diminish the DNA damage induced in HepG2 cells by 4-NQO and B[a]P in 31% and 10%, respectively at 10 microg/mL. Pre-treatment of HepG2 cells with 2',4'-dihydroxychalcone was highly effective in decreasing B[a]P-induced DNA damage at a statistically significant level, with an almost clear dose-response relationship. The inhibition values were 28.2-43.9% for the tested concentrations of 0.01-1 microg/mL, respectively. The results clearly indicate that the phytoextract from Zuccagnia punctata, under the experimental conditions tested, is not genotoxic and that 2',4'-dihydroxychalcone contributes to a high degree to the antigenotoxic effects of Zuccagnia punctata tincture.

Genotoxic and clastogenic effects of monohaloacetic acid drinking water disinfection by-products in primary human lymphocytes.

PubMed

Escobar-Hoyos, Luisa F; Hoyos-Giraldo, Luz Stella; Londoño-Velasco, Elizabeth; Reyes-Carvajal, Ingrid; Saavedra-Trujillo, Diana; Carvajal-Varona, Silvio; Sánchez-Gómez, Adalberto; Wagner, Elizabeth D; Plewa, Michael J

2013-06-15

The haloacetic acids (HAAs) are the second-most prevalent class of drinking water disinfection by-products formed by chemical disinfectants. Previous studies have determined DNA damage and repair of HAA-induced lesions in mammalian and human cell lines; however, little is known of the genomic DNA and chromosome damage induced by these compounds in primary human cells. The aim of this study was to evaluate the genotoxic and clastogenic effects of the monoHAA disinfection by-products in primary human lymphocytes. All monoHAAs were genotoxic in primary human lymphocytes, the rank order of genotoxicity and cytotoxicity was IAA > BAA > CAA. After 6 h of repair time, only 50% of the DNA damage (maximum decrease in DNA damage) was repaired compared to the control. This demonstrates that primary human lymphocytes are less efficient in repairing the induced damage by monoHAAs than previous studies with mammalian cell lines. In addition, the monoHAAs induced an increase in the chromosome aberration frequency as a measurement of the clastogenic effect of these compounds. These results coupled with genomic technologies in primary human cells and other mammalian non-cancerous cell lines may lead to the identification of biomarkers that may be employed in feedback loops to aid water chemists and engineers in the overall goal of producing safer drinking water. Copyright © 2013 Elsevier Ltd. All rights reserved.

Genotoxicity testing on the international space station: Preparatory work on the SOS-LUX test as part of the space experiment TRIPLE-LUX

NASA Astrophysics Data System (ADS)

Stojicic, Nevena; Walrafen, David; Baumstark-Khan, Christa; Rabbow, Elke; Rettberg, Petra; Weisshaar, Maria-Paz; Horneck, Gerda

Harmful environmental factors - namely ionizing radiation - will continue to influence future manned space missions. The Radiation Biology Unit at the German Aerospace Center (DLR) develops cellular monitoring systems, which include bacterial and mammalian cell systems capable of recognizing DNA damage as a consequence of the presence of genotoxic conditions. Such a bioassay is the SOS-LUX test, which represents the radiobiological part of the German space experiment "Gene, immune and cellular responses to single and combined space flight conditions (TRIPLE-LUX)" which has been selected by the IDI/USRA Peer Review Panel for NASA/ESA to be performed on the International Space Station (ISS). It will supply basic information on the genotoxic response to radiation applied in microgravity. The biological end-point under investigation will depend on the bacterial SOS response brought about by genetically modified bacteria that are transformed with the pSWITCH plasmid (constructed from the plasmids pPLS-1 and pGFPuv). The luminescent/fluorescent bioassay SWITCH (SWITCH: Salmonella Weighting of Induced Toxicity Cyto/GenoTox for Human Health) as successor of the SOS-LUX test for rapid toxicity (genotoxicity and cytotoxicity) testing, makes use of two sensing and reporting systems for the two biological endpoints under investigation: the SOS-LUX test and the LAC- Fluoro test. The SWITCH plasmid carries the promoterless lux operon of Photobacterium leiognathi as reporter element under the control of the DNA-damage-dependent SOS promoter of ColD as sensor element (for genotoxicity testing) and the sequences for a hybrid protein consisting of β-galactosidase and GFPuv of Aequorea victoria as reporter element under the control of the (in Salmonella constitutively active) LAC promoter of Escherichia coli as sensor element (for cytotoxicity testing). The system has worked properly for terrestrial applications during the first experiments. Experiments using X-rays and UV radiation of various qualities (from UVC to UVA) have given insights into cellular mechanisms relevant for estimation of health risks, resulting from exposure of astronauts to the extraordinary radiation environment of space.

Genotoxic, Cytotoxic, Antigenotoxic, and Anticytotoxic Effects of Sulfonamide Chalcone Using the Ames Test and the Mouse Bone Marrow Micronucleus Test

PubMed Central

Borges, Flávio Fernandes Veloso; Bernardes, Aline; Perez, Caridad Noda; Silva, Daniela de Melo e

2015-01-01

Chalcones present several biological activities and sulfonamide chalcone derivatives have shown important biological applications, including antitumor activity. In this study, genotoxic, cytotoxic, antigenotoxic, and anticytotoxic activities of the sulfonamide chalcone N-{4-[3-(4-nitrophenyl)prop-2-enoyl]phenyl} benzenesulfonamide (CPN) were assessed using the Salmonella typhimurium reverse mutation test (Ames test) and the mouse bone marrow micronucleus test. The results showed that CPN caused a small increase in the number of histidine revertant colonies in S. typhimurium strains TA98 and TA100, but not statistically significant (p > 0.05). The antimutagenicity test showed that CPN significantly decreased the number of His+ revertants in strain TA98 at all doses tested (p < 0.05), whereas in strain TA100 this occurred only at doses higher than 50 μg/plate (p < 0.05). The results of the micronucleus test indicated that CPN significantly increased the frequency of micronucleated polychromatic erythrocytes (MNPCE) at 24 h and 48 h, revealing a genotoxic effect of this compound. Also, a significant decrease in polychromatic/normochromatic erythrocyte ratio (PCE/NCE) was observed at the higher doses of CPN at 24 h and 48 h (p < 0.05), indicating its cytotoxic action. CPN co-administered with mitomycin C (MMC) significantly decreased the frequency of MNPCE at almost all doses tested at 24 h (p < 0.05), showing its antigenotoxic activity, and also presented a small decrease in MNPCE at 48 h (p > 0.05). Additionally, CPN co-administered with MMC significantly increased PCE/NCE ratio at all doses tested, demonstrating its anticytotoxic effect. In summary, CPN presented genotoxic, cytotoxic, antigenotoxic, and anticytotoxic properties. PMID:26335560

Linking embryo toxicity with genotoxic responses in the freshwater snail Physa acuta: single exposure to benzo(a)pyrene, fluoxetine, bisphenol A, vinclozolin and exposure to binary mixtures with benzo(a)pyrene.

PubMed

Sánchez-Argüello, Paloma; Aparicio, Natalia; Fernández, Carlos

2012-06-01

Genotoxic effects on fauna after waterborne pollutant exposure have been demonstrated by numerous research programmes. Less effort has been focused on establishing relationship between genotoxicity and long-term responses at higher levels of biological organization. Taking into account that embryos may be more sensitive indicators of reproductive impairment than alterations in fertility, we have developed two assays in multiwell plates to address correlations between embryo toxicity and genotoxicity. The potential teratogenicity was assessed by analyzing abnormal development and mortality of Physa acuta at embryonic stage. Genotoxicity was measured by the micronucleus (MN) test using embryonic cells. Our results showed that linkage between genotoxicity and embryo toxicity depends on mechanisms of action of compounds under study. Embryo toxic responses showed a clear dose-related tendency whereas no clear dose-dependent effect was observed in micronucleus induction. The higher embryo toxicity was produced by benzo(a)pyrene exposure followed by fluoxetine and bisphenol A. Vinclozolin was the lower embryo toxic compound. Binary mixtures with BaP always resulted in higher embryo toxicity than single exposures but antagonistic effects were observed for MN induction. Benzo(a)pyrene produced the higher MN induction at 0.04 mg/L, which also produced clear embryo toxic effects. Fluoxetine did not induce cytogenetic effects but 0.25mg/L altered embryonic development. Bisphenol A significantly reduced hatchability at 0.5mg/L while MN induction appeared with higher treatments than those that start causing teratogenicity. Much higher concentration of vinclozolin (5mg/L) reduced hatchability and induced maximum MN formation. In conclusion, while validating one biomarker of genotoxicity and employing one ecologically relevant effect, we have evaluated the relative sensitivity of a freshwater mollusc for a range of chemicals. The embryo toxicity test is a starting point for the development of a life cycle test with freshwater snails even for undertaking multigeneration studies focused on transgenerational effects. Copyright © 2012 Elsevier Inc. All rights reserved.

In vitro testing for genotoxicity of indigo naturalis assessed by micronucleus test.

PubMed

Dominici, Luca; Cerbone, Barbara; Villarini, Milena; Fatigoni, Cristina; Moretti, Massimo

2010-07-01

In the field of cosmetic dyes, used for coloring the hair and skin, there is a clear tendency to replace the widely used synthetic dyes by natural colorants, such as henna and mixtures of henna with indigo. The aim of this study was to estimate the genotoxicity of water and DMSO solutions of indigo naturalis (prepared from Indigofera tinctoria leaves) using the cytokinesis-blocked micronucleus (CBMN) assay in the human metabolically active HepG2 cell line. The cytotoxic effects of indigo solutions were first assessed by propidium iodide and fluorescein-diacetate simultaneous staining. For both solutions, cytotoxicity was always under 10%. Data obtained in the CBMN assay (for all concentrations tested) indicated that the frequency of MN (micronuclei) in exposed cells was no higher than the control. Both the water and DMSO solutions showed the same behavior. These results indicate that indigo naturalis exhibits neither cytotoxicity, nor genotoxicity for all concentrations tested, which may justify excluding indigofera and its components from the list of carcinogenic agents.

Genotoxicity evaluation of effluents from textile industries of the region Fez-Boulmane, Morocco: a case study.

PubMed

Giorgetti, Lucia; Talouizte, Hakima; Merzouki, Mohammed; Caltavuturo, Leonardo; Geri, Chiara; Frassinetti, Stefania

2011-11-01

In order to investigate the biological hazard of effluents from textile industries of Fez-Boulmane region in Morocco, mutagenicity and phytotoxicity tests were performed on different biological systems. Moreover, the efficiency of a Sequencing Batch Reactor (SBR) system, working by activated sludge on a laboratory scale, was estimated by comparing the ecotoxicity results observed before and after wastewater treatment. Evaluation of the genotoxic potential was investigated by means of classic mutagenicity tests on D7 strain of Saccharomyces cerevisiae and by phytotoxicity tests on Allium sativum L., Vicia faba L. and Lactuca sativa L., estimating micronuclei presence, mitotic index and cytogenetic anomalies. The results obtained by testing untreated wastewater demonstrated major genotoxicity effects in S. cerevisiae and various levels of phytotoxicity in the three plant systems, while after SBR treatment no more ecotoxicological consequences were observed. These data confirm the effectiveness of the SBR system in removing toxic substances from textile wastewaters in Fez-Boulmane region. Copyright © 2011 Elsevier Inc. All rights reserved.

Hazard identification by methods of animal-based toxicology.

PubMed

Barlow, S M; Greig, J B; Bridges, J W; Carere, A; Carpy, A J M; Galli, C L; Kleiner, J; Knudsen, I; Koëter, H B W M; Levy, L S; Madsen, C; Mayer, S; Narbonne, J-F; Pfannkuch, F; Prodanchuk, M G; Smith, M R; Steinberg, P

2002-01-01

This paper is one of several prepared under the project "Food Safety In Europe: Risk Assessment of Chemicals in Food and Diet" (FOSIE), a European Commission Concerted Action Programme, organised by the International Life Sciences Institute, Europe (ILSI). The aim of the FOSIE project is to review the current state of the science of risk assessment of chemicals in food and diet, by consideration of the four stages of risk assessment, that is, hazard identification, hazard characterisation, exposure assessment and risk characterisation. The contribution of animal-based methods in toxicology to hazard identification of chemicals in food and diet is discussed. The importance of first applying existing technical and chemical knowledge to the design of safety testing programs for food chemicals is emphasised. There is consideration of the presently available and commonly used toxicity testing approaches and methodologies, including acute and repeated dose toxicity, reproductive and developmental toxicity, neurotoxicity, genotoxicity, carcinogenicity, immunotoxicity and food allergy. They are considered from the perspective of whether they are appropriate for assessing food chemicals and whether they are adequate to detect currently known or anticipated hazards from food. Gaps in knowledge and future research needs are identified; research on these could lead to improvements in the methods of hazard identification for food chemicals. The potential impact of some emerging techniques and toxicological issues on hazard identification for food chemicals, such as new measurement techniques, the use of transgenic animals, assessment of hormone balance and the possibilities for conducting studies in which common human diseases have been modelled, is also considered.

Use of the microscreen phage-induction assay to assess the genotoxicity of 14 hazardous industrial wastes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Houk, V.S.; DeMarini, D.M.

1988-01-01

The Microscreen phage-induction assay, which quantitatively measures the induction of prophage lambda in Escherichia coli WP2s(lambda), was used to test 14 crude (unfractionated) hazardous industrial waste samples for genotoxic activity in the presence and absence of metabolic activation. Eleven of the 14 wastes induced prophage, and induction was observed at concentrations as low as 0.4 pg per ml. Comparisons between the ability of these waste samples to induce prophage and their mutagenicity in the Salmonella reverse mutation assay indicate that the phage-induction assay detected genotoxic activity in all but one of the wastes that were mutagenic in Salmonella. Moreover, themore » Microscreen assay detected as genotoxic five additional wastes that were not detected in the Salmonella assay. The applicability of the Microscreen phage-induction assay for screening hazardous wastes for genotoxic activity is discussed, as are some of the problems associated with screening highly toxic wastes containing toxic volatile compounds.« less

Use of the Microscreen phage-induction assay to assess the genotoxicity of 14 hazardous industrial wastes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Houk, V.S.; DeMarini, D.M.

1988-01-01

The Microscreen phage-induction assay, which quantitatively measures the induction of prophage lambda in Escherichia coli WP2s lambda, was used to test 14 crude (unfractionated) hazardous industrial-waste samples for genotoxic activity in the presence and absence of metabolic activation. Eleven of the 14 wastes induced prophage, and induction was observed at concentrations as low as 0.4 picograms per ml. Comparisons between the mutagenicity of these waste samples in Salmonella and their ability to induce prophage lambda indicate that the Microscreen phage-induction assay detected genotoxic activity in all but one of the wastes that were mutagenic in Salmonella. Moreover, the Microscreen assaymore » detected as genotoxic 5 additional wastes that were not detected in the Salmonella assay. The applicability of the Microscreen phage-induction assay for screening hazardous wastes for genotoxic activity is discussed along with some of the problems associated with screening highly toxic wastes containing toxic volatile compounds.« less

Bioassessment of the Effluents Discharged from Two Export Oriented Industrial Zones Located in Kelani River Basin, Sri Lanka Using Erythrocytic Responses of the Fish, Nile Tilapia (Oreochromis niloticus).

PubMed

Hemachandra, C K; Pathiratne, A

2017-10-01

Complex effluents originating from diverse industrial processes in industrial zones could pose cytotoxic/genotoxic hazards to biota in the receiving ecosystems which cannot be revealed by conventional monitoring methods. This study assessed potential cytotoxicity/genotoxicity of treated effluents of two industrial zones which are discharged into Kelani river, Sri Lanka combining erythrocytic abnormality tests and comet assay of the tropical model fish, Nile tilapia. Exposure of fish to the effluents induced erythrocytic DNA damage and deformed erythrocytes with serrated membranes, vacuolations, nuclear buds and micronuclei showing cytotoxic/genotoxic hazards in all cases. Occasional exceedance of industrial effluent discharge regulatory limits was noted for color and lead which may have contributed to the observed cytotoxicity/genotoxicity of effluents. The results demonstrate that fish erythrocytic responses could be used as effective bioanalytical tools for cytotoxic/genotoxic hazard assessments of complex effluents of industrial zones for optimization of the waste treatment process in order to reduce biological impacts.

Prediction of genotoxic potential of cosmetic ingredients by an in silico battery system consisting of a combination of an expert rule-based system and a statistics-based system.

PubMed

Aiba née Kaneko, Maki; Hirota, Morihiko; Kouzuki, Hirokazu; Mori, Masaaki

2015-02-01

Genotoxicity is the most commonly used endpoint to predict the carcinogenicity of chemicals. The International Conference on Harmonization (ICH) M7 Guideline on Assessment and Control of DNA Reactive (Mutagenic) Impurities in Pharmaceuticals to Limit Potential Carcinogenic Risk offers guidance on (quantitative) structure-activity relationship ((Q)SAR) methodologies that predict the outcome of bacterial mutagenicity assay for actual and potential impurities. We examined the effectiveness of the (Q)SAR approach with the combination of DEREK NEXUS as an expert rule-based system and ADMEWorks as a statistics-based system for the prediction of not only mutagenic potential in the Ames test, but also genotoxic potential in mutagenicity and clastogenicity tests, using a data set of 342 chemicals extracted from the literature. The prediction of mutagenic potential or genotoxic potential by DEREK NEXUS or ADMEWorks showed high values of sensitivity and concordance, while prediction by the combination of DEREK NEXUS and ADMEWorks (battery system) showed the highest values of sensitivity and concordance among the three methods, but the lowest value of specificity. The number of false negatives was reduced with the battery system. We also separately predicted the mutagenic potential and genotoxic potential of 41 cosmetic ingredients listed in the International Nomenclature of Cosmetic Ingredients (INCI) among the 342 chemicals. Although specificity was low with the battery system, sensitivity and concordance were high. These results suggest that the battery system consisting of DEREK NEXUS and ADMEWorks is useful for prediction of genotoxic potential of chemicals, including cosmetic ingredients.

An evaluation of a genotoxicity assay with liver s9 for activation and luminescent bacteria for detection

USGS Publications Warehouse

Johnson, B. Thomas

1992-01-01

A new short-term in vitro genotoxicity assay with marine bioluminescent bacteria was evaluated for sensitivity and cost. Known under the trade name of Mutatox™, this assay is a simple and rapid screening tool that detects DNA-damaging substances (genotoxins) by measuring light output from an isolated dark mutant strain of the luminescent bacterium Photobacterium phosphoreum. A positive response indicates the ability of the test chemical to restore the luminescent state in the dark mutant strain; the degree of light increase indicates the relative genotoxicity of the sample. In this study, the Mutatox assay with rat hepatic fractions (S9) as an exogenous metabolic activation system detected genotoxic activity with known progenotoxins: 2-acetamidofluorene, aflatoxin B1, 2-aminoanthracene, 2-aminofluorene, 2-aminonaphthalene, benzo[a]pyrene, 3-methyl-cholanthrene, and pyrene. Each chemical clearly demonstrated a dose response between 5.0 and 0.6 μg per tube. Known nongenotoxic controls carbofuran, di-2-ethylhexyl phthalate, malathion, simazine, and permethrin showed no genotoxic responses. The optimum assay conditions were determined to be rat S9 concentration of 0.4 mg/ml, preincubation at 37°C for 30 min, and 18 h incubation at 23°C. Genotoxicity data were obtained in <24 h. The Mutatox assay compared favorably in sensitivity with the Ames test; it was easier and more rapid to perform and, as a result, cost less. The sensitivity, specificity, and predictive value suggested that the Mutatox assay could be a valuable screening tool to monitor complex environmental samples for genotoxins.

Comparison of the in vivo and in vitro genotoxicity of glyphosate isopropylamine salt in three different organisms

PubMed Central

Alvarez-Moya, Carlos; Silva, Mónica Reynoso; Ramírez, Carlos Valdez; Gallardo, David Gómez; Sánchez, Rafael León; Aguirre, Alejandro Canales; Velasco, Alfredo Feria

2014-01-01

There is considerable controversy with regard to the genotoxicity of glyphosate, with some reports stating that this compound is non-toxic for fish, birds and mammals. In this work, we used the comet assay to examine the genotoxicity of glyphosate isopropylamine (0.7, 7, 70 and 700 μM) in human lymphocytes, erythrocytes of Oreochromis niloticus and staminal nuclei of Tradescantia (4430) in vitro and in vivo. Cells, nuclei and fish that had and had not been exposed to 5 mM N-nitrosodiethylamine (NDEA) were used as positive and negative controls, respectively. Significant (p < 0.01) genetic damage was observed in vivo and in vitro in all cell types and organisms tested. Human lymphocytes and Tradescantia hairs showed lower genetic damage in vivo compared to in vitro, possibly because of efficient metabolization of the herbicide. In O. niloticus erythrocytes, significant (p < 0.001) genotoxicity was observed at ≥ 7 μM, whereas in vitro, glyphosphate was genotoxic in human lymphocytes and Tradescantia hairs at ≥ 0.7 μM. These results indicate that glyphosate is genotoxic in the cells and organisms studied at concentrations of 0.7–7 μM. PMID:24688297

Comparison of the in vivo and in vitro genotoxicity of glyphosate isopropylamine salt in three different organisms.

PubMed

Alvarez-Moya, Carlos; Silva, Mónica Reynoso; Ramírez, Carlos Valdez; Gallardo, David Gómez; Sánchez, Rafael León; Aguirre, Alejandro Canales; Velasco, Alfredo Feria

2014-03-01

There is considerable controversy with regard to the genotoxicity of glyphosate, with some reports stating that this compound is non-toxic for fish, birds and mammals. In this work, we used the comet assay to examine the genotoxicity of glyphosate isopropylamine (0.7, 7, 70 and 700 μM) in human lymphocytes, erythrocytes of Oreochromis niloticus and staminal nuclei of Tradescantia (4430) in vitro and in vivo. Cells, nuclei and fish that had and had not been exposed to 5 mM N-nitrosodiethylamine (NDEA) were used as positive and negative controls, respectively. Significant (p < 0.01) genetic damage was observed in vivo and in vitro in all cell types and organisms tested. Human lymphocytes and Tradescantia hairs showed lower genetic damage in vivo compared to in vitro, possibly because of efficient metabolization of the herbicide. In O. niloticus erythrocytes, significant (p < 0.001) genotoxicity was observed at ≥ 7 μM, whereas in vitro, glyphosphate was genotoxic in human lymphocytes and Tradescantia hairs at ≥ 0.7 μM. These results indicate that glyphosate is genotoxic in the cells and organisms studied at concentrations of 0.7-7 μM.

Evaluation of High-throughput Genotoxicity Assays Used in Profiling the US EPA ToxCast Chemicals

EPA Science Inventory

Three high-throughput screening (HTS) genotoxicity assays-GreenScreen HC GADD45a-GFP (Gentronix Ltd.), CellCiphr p53 (Cellumen Inc.) and CellSensor p53RE-bla (Invitrogen Corp.)-were used to analyze the collection of 320 predominantly pesticide active compounds being tested in Pha...

Genotoxicity and Cytotoxicity Evaluation of the Neolignan Analogue 2-(4-Nitrophenoxy)-1Phenylethanone and its Protective Effect Against DNA Damage

PubMed Central

Hanusch, Alex Lucas; de Oliveira, Guilherme Roberto; de Sabóia-Morais, Simone Maria Teixeira; Machado, Rafael Cosme; dos Anjos, Murilo Machado; Chen Chen, Lee

2015-01-01

Neolignans are secondary metabolites found in various groups of Angiosperms. They belong to a class of natural compounds with great diversity of chemical structures and pharmacological activities. These compounds are formed by linking two phenylpropanoid units. Several compounds that have ability to prevent genetic damage have been isolated from plants, and can be used to prevent or delay the development of tumor cells. Genetic toxicology evaluation is widely used in risk assessment of new drugs in preclinical screening tests. In this study, we evaluated the genotoxicity and cytotoxicity of the neolignan analogue 2-(4-nitrophenoxy)-1-phenylethanone (4NF) and its protective effect against DNA damage using the mouse bone marrow micronucleus test and the comet assay in mouse peripheral blood. Our results showed that this neolignan analogue had no genotoxic activity and was able to reduce induced damage both in mouse bone marrow and peripheral blood. Although the neolignan analogue 4NF was cytotoxic, it reduced cyclophosphamide-induced cytotoxicity. In conclusion, it showed no genotoxic action, but exhibited cytotoxic, antigenotoxic, and anticytotoxic activities. PMID:26554835

Dragon's blood Croton palanostigma induces genotoxic effects in mice.

PubMed

Maistro, Edson Luis; Ganthous, Giulia; Machado, Marina da Silva; Zermiani, Tailyn; Andrade, Sérgio Faloni de; Rosa, Paulo Cesar Pires; Perazzo, Fabio Ferreira

2013-05-20

Dragon's blood is a dark-red sap produced by species from the genus Croton (Euphorbiaceae), which has been used as a famous traditional medicine since ancient times in many countries, with scarce data about its safe use in humans. In this research, we studied genotoxicity and clastogenicity of Croton palanostigma sap using the comet assay and micronucleus test in cells of mice submitted to acute treatment. HPLC analysis was performed to identify the main components of the sap. The sap was administered by oral gavage at doses of 300 mg/kg, 1,000 mg/kg and 2,000 mg/kg. For the analysis, the comet assay was performed on the leukocytes and liver cells collected 24h after treatment, and the micronucleus test (MN) on bone marrow cells. Cytotoxicity was assessed by scoring 200 consecutive polychromatic (PCE) and normochromatic (NCE) erythrocytes (PCE/NCE ratio). The alkaloid taspine was the main compound indentified in the crude sap of Croton palanostigma. The results of the genotoxicity assessment show that all sap doses tested produced genotoxic effects in leukocytes and liver cells and also produced clastogenic/aneugenic effects in bone marrow cells of mice at the two higher doses tested. The PCE/NCE ratio indicated no cytotoxicity. The data obtained suggest caution in the use of Croton palanostigma sap by humans considering its risk of carcinogenesis. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

A comprehensive statistical classifier of foci in the cell transformation assay for carcinogenicity testing.

PubMed

Callegaro, Giulia; Malkoc, Kasja; Corvi, Raffaella; Urani, Chiara; Stefanini, Federico M

2017-12-01

The identification of the carcinogenic risk of chemicals is currently mainly based on animal studies. The in vitro Cell Transformation Assays (CTAs) are a promising alternative to be considered in an integrated approach. CTAs measure the induction of foci of transformed cells. CTAs model key stages of the in vivo neoplastic process and are able to detect both genotoxic and some non-genotoxic compounds, being the only in vitro method able to deal with the latter. Despite their favorable features, CTAs can be further improved, especially reducing the possible subjectivity arising from the last phase of the protocol, namely visual scoring of foci using coded morphological features. By taking advantage of digital image analysis, the aim of our work is to translate morphological features into statistical descriptors of foci images, and to use them to mimic the classification performances of the visual scorer to discriminate between transformed and non-transformed foci. Here we present a classifier based on five descriptors trained on a dataset of 1364 foci, obtained with different compounds and concentrations. Our classifier showed accuracy, sensitivity and specificity equal to 0.77 and an area under the curve (AUC) of 0.84. The presented classifier outperforms a previously published model. Copyright © 2017 Elsevier Ltd. All rights reserved.

Assessment of the genotoxicity of 137Cs radiation using Vicia-micronucleus, Tradescantia-micronucleus and Tradescantia-stamen-hair mutation bioassays.

PubMed

Minouflet, Marion; Ayrault, Sophie; Badot, Pierre-Marie; Cotelle, Sylvie; Ferard, Jean-François

2005-01-01

Since the middle of the 20th century, ionizing radiations from radioactive isotopes including 137Cs have been investigated to determine their genotoxic impact on living organisms. The present study was designed to compare the effectiveness of three plant bioassays to assess DNA damage induced by low doses of 137Cs: Vicia-micronucleus test (Vicia-MCN), Tradescantia-micronucleus test (Trad-MCN) and Tradescantia-stamen-hair mutation test (Trad-SH) were used. Vicia faba (broad bean) and Tradescantia clone 4430 (spiderwort) were exposed to 137Cs according to different scenarios: external and internal (contamination) irradiations. Experiments were conducted with various levels of radioactivity in solution or in soil, using solid or liquid 137Cs sources. The three bioassays showed different sensitivities to the treatments. Trad-MCN appeared to be the most sensitive test (significative response from 1.5 kBq/200 ml after 30 h of contamination). Moreover, at comparable doses, internal irradiations led to larger effects for the three bioassays. These bioassays are effective tests for assessing the genotoxic effects of radioactive 137Cs pollution.

Olive (Olea europaea L.) leaf extract counteracts genotoxicity and oxidative stress of permethrin in human lymphocytes.

PubMed

Türkez, Hasan; Toğar, Başak

2011-10-01

The aim of this study was to investigate the protective effects of olive leaf extract (OLE) on genotoxicity and oxidative damage in cultured human blood cells treated with permethrin (PM) in the presence of a rat liver S9 mix containing cytochrome P 450 enzymes. Anti-genotoxic activities of OLE were studied using sister chromatid exchange (SCE) and chromosome aberration (CA) tests and furthermore total antioxidant capacity (TAC) and total oxidative status (TOS) were examined to determine the oxidative damage. Our results clearly revealed that treatment with PM (200 mg/l) alone increased SCE and CA rates and TOS level, decreased TAC level in cultured human blood cells. The OLE alone at the all tested doses did not induce any significant changes in the genotoxicity endpoint. However OLE leads to increases of plasma TAC level in vitro. OLE starts showing this positive effect at 100 mg/l. The combined treatment showed significant improvements in cytogenetic and biochemical parameters tested. Moreover, this improvement was more pronounced in the group received the high dose of the OLE. It could be concluded that the ethanol extract of OLE induced its genoprotective effect via the increase in the antioxidant capacity, inhibition of oxidative stress and scavenging of free radicals.

Evaluation of the genotoxicity of Euterpe oleraceae Mart. (Arecaceae) fruit oil (açaí), in mammalian cells in vivo.

PubMed

Marques, E S; Froder, J G; Carvalho, J C T; Rosa, P C P; Perazzo, F F; Maistro, E L

2016-07-01

E. oleracea is a tropical plant from the Amazon region, with its fruit used for food, and traditionally, as an antioxidant, anti-inflammatory, hypocholesterolemic, for atherosclerotic disease, and has anticancer properties. The oil of the fruit has antidiarrheic, anti-inflammatory and antinociceptive activities, but without genotoxicity evaluation. Therefore, the aim of this study was to evaluate the genotoxic potential of E. oleracea fruit oil (EOO), in rat cells. Male Wistar rats were treated with EOO by gavage at doses of 30, 100 and 300 mg/kg, for 14 days, within a 24 h interval. The DNA damage in the leukocytes, liver, bone marrow and testicular cells, was assessed by the comet assay, and the clastogenic/aneugenic effects in the bone marrow cells, by the micronucleus test. Our phytochemicals characterization of the EOO showed the presence of vanillic, palmitic, γ-linolenic, linoleic, oleic, cinnamic, caffeic, protocatechuic, ferulic, syringic acids, and flavonoids quercetin and kaempferol rutinoside as the main constituents. Both cytogenetic tests performed showed that EOO presented no significant genotoxic effects in the analyzed cells, at the three tested doses. These results indicate that, under our experimental conditions, E. oleracea fruit oil did not reveal genetic toxicity in rat cells. Copyright © 2016. Published by Elsevier Ltd.

Evaluation of the genotoxicity of alpha-amanitin in mice bone marrow cells.

PubMed

Marciniak, B; Łopaczyńska, D; Ferenc, T

2017-10-01

Alpha-amanitin is a known cytotoxic substance found in some mushroom species including Amanita phalloides. Its main mechanism of action is to block the transcription, which can lead to cell death. Lack of reports on the genotoxicity of this toxin was an inspiration for undertaking this experiment. Genotoxic effect of α-amanitin on balb/c mice bone marrow cells was tested using: comet assay and chromosomal aberration test. The tested substance was given once by intraperitoneal administration to animals at doses: 0.1 mg/kg, 0.15 mg/kg and 0.25 mg/kg (LD 50 ) body weight with 48 h exposure. The comet assay demonstrated a statistically significant increase in DNA damage for all the investigated α-amanitin doses compared to the negative control (p < 0.0001). The exposure to 0.15 and 0.25 mg/kg doses of α-amanitin also generated a statistically significant increase in the frequency of chromosomal aberrations in bone marrow cells of mice compared to the negative control (p < 0.05). The genotoxic effect induced by α-amanitin in mammalian cells can result in genome instability and its functional consequences. Copyright © 2017 Elsevier Ltd. All rights reserved.

Absence of subchronic oral toxicity and genotoxicity of rice koji with Aspergillus terreus.

PubMed

Yun, Jun-Won; Kim, Seung-Hyun; Kim, Yun-Soon; You, Ji-Ran; Cho, Eun-Young; Yoon, Jung-Hee; Kwon, Euna; Lee, Sang Ju; Kim, Seong Pil; Seo, Jae Hoon; In, Jae Pyung; Ahn, Jae Hun; Jang, Ja-June; Park, Jin-Sung; Che, Jeong-Hwan; Kang, Byeong-Cheol

2017-10-01

Koji products have been considered as an effective fermented food consumed in East Asia with many health benefits. Particularly, rice koji with Aspergillus terreus (RAT) has been reported to be able to prevent hyperlipidemia and hepatic steatosis through regulating cholesterol synthesis. Despite its biological activities, there is a lack of comprehensive information to give an assurance of its safety. Therefore, the objective of this study was to perform a series of toxicological studies (repeated dose oral toxicity and genotoxicity) according to test guidelines published by the Organization for Economic Cooperation and Development. Along with acute toxicity study using rats and beagle dogs, a 13-week toxicity study revealed no clear RAT-related toxic changes, including body weight, mortality, hematology, serum biochemistry, organ weight, and histopathology after oral administration at doses of 500, 1000, and 2000 mg/kg BW. The no-observed-adverse-effect level of RAT was considered to be more than 2000 mg/kg BW/day in rats of both genders. In addition, potential genotoxicity was evaluated using a standard battery of tests (Ames test, chromosome aberration assay, and micronucleus assay) which revealed that RAT showed no genotoxicity. Accordingly, these results suggest that RAT is a safe and non-toxic functional food for human consumption at proper dose. Copyright © 2017. Published by Elsevier Inc.

Genetic toxicology in the 21st century: Reflections and future ...

EPA Pesticide Factsheets

A symposium at the 40th anniversary of the Environmental Mutagen Society, held from October 24–28, 2009 in St. Louis, MO, surveyed the current status and future directions of genetic toxicology. This article summarizes the presentations and provides a perspective on the future. An abbreviated history is presented, highlighting the current standard battery of genotoxicity assays and persistent challenges. Application of computational toxicology to safety testing within a regulatory setting is discussed as a means for reducing the need for animal testing and human clinical trials, and current approaches and applications of in silico genotoxicity screening approaches across the pharmaceutical industry were surveyed and are reported here. The expanded use of toxicogenomics to illuminate mechanisms and bridge genotoxicity and carcinogenicity, and new public efforts to use high-throughput screening technologies to address lack of toxicity evaluation for the backlog of thousands of industrial chemicals in the environment are detailed. The Tox21 project involves coordinated efforts of four U.S. Government regulatory/research entities to use new and innovative assays to characterize key steps in toxicity pathways, including genotoxic and nongenotoxic mechanisms for carcinogenesis. Progress to date, highlighting preliminary test results from the National Toxicology Program is summarized. Finally, an overview is presented of ToxCast™, a related research program of the

GENOTOXICITY AND IDENTIFICATION OF THE MAJOR DNA-ADDUCTS OF ACEANTHRYLENE

EPA Science Inventory

Aceanthrylene (ACE), a cyclopenta-fused polycyclic aromatic hydrocarbon (CP-PAH) derivative of anthracene has been shown to be highly mutagenic in Salmonella typhimurium strain TA98 (1). C3H10T1/2CL8 (C3H10T1/2) mouse embryo fibroblasts have been used to study the metabolism and ...

Genotoxicity testing approaches for the safety assessment of substances used in food contact materials prior to their authorization in the European Union.

PubMed

Bolognesi, Claudia; Castoldi, Anna F; Crebelli, Riccardo; Barthélémy, Eric; Maurici, Daniela; Wölfle, Detlef; Volk, Katharina; Castle, Laurence

2017-06-01

Food contact materials are all materials and articles intended to come directly or indirectly into contact with food. Before being included in the positive European "Union list" of authorized substances (monomers, other starting substances and additives) for plastic food contact materials, the European Food Safety Authority (EFSA) must assess their safety "in use". If relevant for risk, the safety of the main impurities, reaction and degradation products originating from the manufacturing process is also evaluated. Information on genotoxicity is always required irrespective of the extent of migration and the resulting human exposure, in view of the theoretical lack of threshold for genotoxic events. The 2008 EFSA approach, requiring the testing of food contact materials in three in vitro mutagenicity tests, though still acceptable, is now superseded by the 2011 EFSA Scientific Committee's recommendation for only two complementary tests including a bacterial gene mutation test and an in vitro micronucleus test, to detect two main genetic endpoints (i.e., gene mutations and chromosome aberrations). Follow-up of in vitro positive results depends on the type of genetic effect and on the substance's systemic availability. In this study, we provide an analysis of the data on genotoxicity testing gathered by EFSA on food contact materials for the period 1992-2015. We also illustrate practical examples of the approaches that EFSA took when evaluating "non standard" food contact chemicals (e.g., polymeric additives, oligomer or other reaction mixtures, and nanosubstances). Additionally, EFSA's experience gained from using non testing methods and/or future possibilities in this area are discussed. Environ. Mol. Mutagen. 58:361-374, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Genotoxicity of two arsenic compounds in germ cells and somatic cells of Drosophila melanogaster

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ramos-Morales, P.; Rodriguez-Arnaiz, R.

Two arsenic compounds, sodium arsenite (NaAsO{sup 2}) and sodium arsenate (Na{sub 2}HasO{sub 4}), were tested for their possible genotoxicity in germinal and somatic cells of Drosophila melanagaster. For germinal cells, the sex-linked recessive lethal test (SLRLT) and the sea chromosome loss test (SCLT) were used. In both tests, a broad scheme of 2-3-3 days was employed. Two routes of administration were used for the SLRLT: adult male injection (0.38, 0.77 mM used for Sodium arsenite; and 0.01, 0.02 mM for sodium arsenate). The the SCLT the compounds were injected into males. Controls were treated with a solution of 5% sucrosemore » which was employed as solvent. The somatic mutation and recombination test (SMART) was run in the w{sup +}/w eye assay as well as in the mwh +/+ flr{sup 3} wing test, employing the standard and insecticide-resistant strains. In both tests, third instar larvae were treated for 6 hr with sodium arsenite (0.38, 0.77, 1.15 mM), and sodium arsenate (0.54, 1.34, 2.69 mM). In the SLRLT, both compounds were positive, but they were negative in the SCLT. The genotoxicity of both compounds was localized mainly in somatic cells, in agreement with reports on the carcinogenic potential of arsenical compounds Solium and arsenite was an order of magnitude more toxic and mutagenic than sodium arsenate. This study confirms the reliability of the Drosophila in vivo system to test the genotoxicity of environmental compounds. 75 refs., 4 figs., 4 tabs.« less

Evaluation of Genotoxic Pressure along the Sava River

PubMed Central

Kračun-Kolarević, Margareta; Kostić, Jovana; Simonović, Predrag; Simić, Vladica; Milošković, Aleksandra; Reischer, Georg; Farnleitner, Andreas; Gačić, Zoran; Milačič, Radmila; Zuliani, Tea; Vidmar, Janja; Pergal, Marija; Piria, Marina; Paunović, Momir; Vuković-Gačić, Branka

2016-01-01

In this study we have performed a comprehensive genotoxicological survey along the 900 rkm of the Sava River. In total, 12 sites were chosen in compliance with the goals of GLOBAQUA project dealing with the effects of multiple stressors on biodiversity and functioning of aquatic ecosystems. The genotoxic potential was assessed using a complex battery of bioassays performed in prokaryotes and aquatic eukaryotes (freshwater fish). Battery comprised evaluation of mutagenicity by SOS/umuC test in Salmonella typhimurium TA1535/pSK1002. The level of DNA damage as a biomarker of exposure (comet assay) and biomarker of effect (micronucleus assay) and the level of oxidative stress as well (Fpg—modified comet assay) was studied in blood cells of bleak and spirlin (Alburnus alburnus/Alburnoides bipunctatus respectively). Result indicated differential sensitivity of applied bioassays in detection of genotoxic pressure. The standard and Fpg—modified comet assay showed higher potential in differentiation of the sites based on genotoxic potential in comparison with micronucleus assay and SOS/umuC test. Our data represent snapshot of the current status of the river which indicates the presence of genotoxic potential along the river which can be traced to the deterioration of quality of the Sava River by communal and industrial wastewaters. The major highlight of the study is that we have provided complex set of data obtained from a single source (homogeneity of analyses for all samples). PMID:27631093

Lack of genotoxicity in Astyanax bimaculatus and Oreochromis niloticus of 17α-methyltestosterone used in fish hatcheries to produce male monosex populations.

PubMed

Rivero-Wendt, C L G; Miranda-Vilela, A L; Ferreira, M F N; Amorim, F S; da Silva, V A G; Louvandini, H; Grisolia, C K

2013-10-24

17α-Methyltestosterone (MT) is widely used in fish hatcheries of many countries to produce male monosex populations. Its genotoxic risk to fish species is not well known and studies in other in vivo models are still inconclusive. MT was tested for genotoxicity in the fish species Oreochromis niloticus (tilapia), a target species, and Astyanax bimaculatus (lambari), a native non-target species. Genotoxicity was evaluated by the micronucleus test (MN), nuclear abnormalities (NA), and comet assay using peripheral erythrocytes of both species after a 96-h exposure to MT at concentrations of 0.01, 0.1, and 1.0 mg/L in the water. At the lowest exposure level of 0.01 mg/L, MT induced MN in both species and NA only in O. niloticus. These effects were not observed in the comet assay. Chromatographic analysis of water samples collected from aquariums at the beginning and end of each experiment showed that MT was consumed during the 96-h exposure. At the highest level of exposure (1.0 mg/L), 81.69% of the hormone was consumed during the exposure period. The chromatogram showed that at the lowest concentration level of 0.01 mg/L, 99.56% MT was consumed by the end of the exposure period. Thus, exposure to MT did not cause genotoxicity in either fish species.

Evaluation of cytotoxicity, genotoxicity, and apoptosis of wastewater before and after disinfection with performic acid.

PubMed

Ragazzo, Patrizia; Feretti, Donatella; Monarca, Silvano; Dominici, Luca; Ceretti, Elisabetta; Viola, Gaia; Piccolo, Valentina; Chiucchini, Nicoletta; Villarini, Milena

2017-06-01

Disinfection with performic acid (PFA) represents an emerging technology in wastewater treatment. Many recent studies indicate its effectiveness and suitability as a disinfectant for different applications; several have demonstrated its reliability as an alternative to chlorine for disinfecting secondary effluents from urban wastewater treatment plants (WWTPs). Some disinfection technologies, in relation to their oxidative power, lead to the formation of disinfection by-products (DBPs), some of which are of concern for their toxic and carcinogenic potential. The aim of this study was to investigate potential genotoxic, cytotoxic, and mutagenic effects of this disinfection agent on treated secondary effluent coming from a municipal WWTP. A strategy with multiple short-term tests and different target cells (bacterial, plant, and mammalian) was adopted to explore a relatively wide range of potential genotoxic events. The Ames test (point mutation in Salmonella), the micronucleus (chromosomal damage) and Comet tests (primary DNA damage) on human hepatic cells (HepG2) were conducted to detect mutagenicity and chromosomal DNA alterations. DNA fragmentation and mitochondrial potential assays were conducted to evaluate apoptosis in the same kinds of cells. Mutagenic and clastogenic effect potentials were evaluated by examining micronucleus formation in Allium cepa root cells. In all the in vitro tests, carried out on both disinfected and non-disinfected effluents, negative results were always obtained for mutagenic and genotoxic effects. In the Allium cepa tests, however, some non-concentrated wastewater samples after PFA treatment induced a slight increase in micronucleus frequencies in root cells, but not in a dose-related manner. In conclusion, PFA applied for disinfection to a secondary effluent from a municipal wastewater treatment plant did not contribute to the release of genotoxic or mutagenic compounds. Further studies are required to establish to which extent these findings can be generalized to support PFA for other disinfection applications. Copyright © 2017 Elsevier Ltd. All rights reserved.

Genotoxicity of antiobesity drug orlistat and effect of caffeine intervention: an in vitro study.

PubMed

Chakrabarti, Manoswini; Ghosh, Ilika; Jana, Aditi; Ghosh, Manosij; Mukherjee, Anita

2017-07-01

Obesity is a major global health problem associated with various adverse effects. Pharmacological interventions are often necessary for the management of obesity. Orlistat is an FDA-approved antiobesity drug which is a potent inhibitor of intestinal lipases. In the current study, orlistat was evaluated for its genotoxic potential in human lymphocyte cells in vitro and was compared with that of another antiobesity drug sibutramine, presently withdrawn from market due its undesirable health effects. Caffeine intake may be an additional burden in people using anorectic drugs, therefore, further work is needed to be carried out to evaluate the possible effects of caffeine on orlistat-induced DNA damage. Human lymphocytes were exposed to orlistat (250, 500 and 1000 μg/ml), sibutramine (250, 500 and 1000 μg/ml) and caffeine (25, 50, 75, 100, 125 and 150 μg/ml) to assess their genotoxicity by comet assay in vitro. In addition, lymphocytes were co-incubated with caffeine (50, 75 and 100 μg/ml) and a single concentration of orlistat (250 μg/ml). Orlistat and sibutramine were genotoxic at all concentrations tested, sibutramine being more genotoxic. Caffeine was found to be genotoxic at concentrations 125 μg/ml and above. Co-treatment of orlistat with non-genotoxic concentrations (50, 75 and 100 μg/ml) of caffeine lead to a decrease in DNA damage. Orlistat can induce DNA damage in human lymphocytes in vitro and caffeine was found to reduce orlistat-induced genotoxicity.

Genotoxic substances in the St. Lawrence system. 1: Industrial genotoxins sorbed to particulate matter in the St. Lawrence, St. Maurice, and Saguenay rivers, Canada

DOE Office of Scientific and Technical Information (OSTI.GOV)

White, P.A.; Rasmussen, J.B.; Blaise, C.

1998-02-01

Previous investigations of organic genotoxins in industrial effluents discharged into the St. Lawrence River system (Quebec, Canada) indicated that a substantial fraction of the genotoxicity is adsorbed to suspended particulate matter. This study used the SOS Chromotest to investigate the presence, potency, and behavior of particle-bound genotoxins in the downstream ecosystem. The results indicate that although extracts of both suspended and sedimented particulate matter are genotoxic, suspended particulate matter samples are more potent in the absence of S9 activation, with the reverse being true for bottom sediments. The results confirmed a positive relationship between the genotoxicity of bottom sediment extractsmore » and sediment organic matter content. A similar relationship between organic matter content and total polycyclic aromatic hydrocarbon (PAH) concentration indicates that putative genotoxins have physicochemical properties similar to the PAH class of contaminants. Conversion of PAH values to benzo[a]pyrene equivalents indicates that measured PAHs only account for a small fraction ({approximately}10%) of the observed SOS Chromotest response. Sites that receive discharges from foundries, aluminum refineries, and petroleum refineries yielded several of the most genotoxic samples. Further analyses revealed that the genotoxicity of suspended and sedimented particulate matter extracts is empirically related to the genotoxicity of industrial discharges. Comparisons of total genotoxicity levels in suspended particulates and bottom sediments suggest that direct-acting substances adsorbed to suspended matter are rapidly degraded and/or converted to more stable progenotoxins upon deposition. Further research is required to test this hypothesis and investigate effects on indigenous biota.« less

A whole-cell bioreporter assay for quantitative genotoxicity evaluation of environmental samples.

PubMed

Jiang, Bo; Li, Guanghe; Xing, Yi; Zhang, Dayi; Jia, Jianli; Cui, Zhisong; Luan, Xiao; Tang, Hui

2017-10-01

Whole-cell bioreporters have emerged as promising tools for genotoxicity evaluation, due to their rapidity, cost-effectiveness, sensitivity and selectivity. In this study, a method for detecting genotoxicity in environmental samples was developed using the bioluminescent whole-cell bioreporter Escherichia coli recA::luxCDABE. To further test its performance in a real world scenario, the E. coli bioreporter was applied in two cases: i) soil samples collected from chromium(VI) contaminated sites; ii) crude oil contaminated seawater collected after the Jiaozhou Bay oil spill which occurred in 2013. The chromium(VI) contaminated soils were pretreated by water extraction, and directly exposed to the bioreporter in two phases: aqueous soil extraction (water phase) and soil supernatant (solid phase). The results indicated that both extractable and soil particle fixed chromium(VI) were bioavailable to the bioreporter, and the solid-phase contact bioreporter assay provided a more precise evaluation of soil genotoxicity. For crude oil contaminated seawater, the response of the bioreporter clearly illustrated the spatial and time change in genotoxicity surrounding the spill site, suggesting that the crude oil degradation process decreased the genotoxic risk to ecosystem. In addition, the performance of the bioreporter was simulated by a modified cross-regulation gene expression model, which quantitatively described the DNA damage response of the E. coli bioreporter. Accordingly, the bioluminescent response of the bioreporter was calculated as the mitomycin C equivalent, enabling quantitative comparison of genotoxicities between different environmental samples. This bioreporter assay provides a rapid and sensitive screening tool for direct genotoxicity assessment of environmental samples. Copyright © 2017. Published by Elsevier Ltd.

Genotoxic effects of environmental endocrine disruptors on the aquatic insect Chironomus riparius evaluated using the comet assay.

PubMed

Martínez-Paz, Pedro; Morales, Mónica; Martínez-Guitarte, José Luis; Morcillo, Gloria

2013-12-12

Genotoxicity is one of the most important toxic endpoints in chemical toxicity testing and environmental risk assessment. The aim of this study was to evaluate the genotoxic potential of various environmental pollutants frequently found in aquatic environments and characterized by their endocrine disrupting activity. Monitoring of DNA damage was undertaken after in vivo exposures of the aquatic larvae of the midge Chironomus riparius, a model organism that represents an abundant and ecologically relevant macroinvertebrate, widely used in freshwater toxicology. DNA-induced damage, resulting in DNA fragmentation, was quantified by the comet assay after short (24 h) and long (96 h) exposures to different concentrations of the selected toxicants: bisphenol A (BPA), nonylphenol (NP), pentachlorophenol (PCP), tributyltin (TBT) and triclosan (TCS). All five compounds were found to have genotoxic activity as demonstrated by significant increases in all the comet parameters (%DNA in tail, tail length, tail moment and Olive tail moment) at all tested concentrations. Persistent exposure did not increase the extent of DNA damage, except for TCS at the highest concentration, but generally there was a reduction in DNA damage thought to be associated with the induction of the detoxification processes and repairing mechanisms. Comparative analysis showed differences in the genotoxic potential between the chemicals, as well as significant time and concentration-dependent variations, which most likely reflect differences in the ability to repair DNA damage under the different treatments. The present report demonstrates the sensitivity of the benthic larvae of C. riparius to these environmental genotoxins suggesting its potential as biomonitor organism in freshwater ecosystems. The results obtained about the DNA-damaging potential of these environmental pollutants reinforce the need for additional studies on the genotoxicity of endocrine active substances that, by linking genotoxic activity to other biological responses, could provide further understanding of adverse effects in aquatic environments. Copyright © 2013 Elsevier B.V. All rights reserved.

From the Cover: An Investigation of the Genotoxicity and Interference of Gold Nanoparticles in Commonly Used In Vitro Mutagenicity and Genotoxicity Assays.

PubMed

George, Jiya M; Magogotya, Millicent; Vetten, Melissa A; Buys, Antoinette V; Gulumian, Mary

2017-03-01

The suitability of 4 in vitro assays, commonly used for mutagenicity and genotoxicity assessment, was investigated in relation to treatment with 14 nm citrate-stabilized gold nanoparticles (AuNPs). Specifically, the Ames test was conducted without metabolic activation, where no mutagenic effects were observed. High resolution transmission electron microscopy and Cytoviva dark-field image analysis showed that AuNPs did not enter the bacterial cells, thus confirming the unreliability of the Ames test for nanoparticle mutagenicity studies. In addition, the Chinese hamster ovary (CHO) cell line was used for Comet, Chromosome aberration and Micronucleus assays. CHO cells were treated with AuNPs for 20 h at 37 °C. Cytotoxicity was not detected by cell impedance studies even though AuNP uptake was confirmed using Cytoviva image analysis. The DNA damage was statistically significant in treated cells when assessed by the Comet assay. However, minimal and nonstatistically significant chromosomal DNA damage was observed using the chromosome aberration and micronucleus assays. In this study, we showed that false positive results obtained with Comet assay may have been due to the possibility of direct contact between the residual, intracellular AuNPs and DNA during the assay procedure. Therefore, the chromosome aberration and micronucleus assays are better suited to assess the genotoxic effects of nanoparticles due to low probability of such direct contact occurring. Genotoxic effect of 14 and 20 nm citrate-stabilized, as well as, 14 nm PCOOH AuNPs were also investigated using chromosome aberration and micronucleus assays. Based on our acceptance criteria for a positive genotoxic response, none of the AuNPs were found to be genotoxic in either of these assays. © The Author 2017. Published by Oxford University Press on behalf of the Society of Toxicology. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Assessment of genotoxic effects of flumorph by the comet assay in mice organs.

PubMed

Zhang, T; Zhao, Q; Zhang, Y; Ning, J

2014-03-01

The present study investigated the genotoxic effects of flumorph in various organs (brain, liver, spleen, kidney and sperm) of mice. The DNA damage, measured as comet tail length (µm), was determined using the alkaline comet assay. The comet assay is a sensitive assay for the detection of genotoxicity caused by flumorph using mice as a model. Statistically significant increases in comet assay for both dose-dependent and duration-dependent DNA damage were observed in all the organs assessed. The organs exhibited the maximum DNA damage in 96 h at 54 mg/kg body weight. Brain showed maximum DNA damage followed by spleen > kidney > liver > sperm. Our data demonstrated that flumorph had induced systemic genotoxicity in mammals as it caused DNA damage in all tested vital organs, especially in brain and spleen.

GENOTOXICITY OF TEN CIGARETTE SMOKE CONDENSATES IN FOUR TEST SYSTEMS: COMPARISONS BETWEEN ASSAYS AND CONDENSATES

EPA Science Inventory

What is the study?
This the first assessment of a set of cigarette smoke condensates from a range of cigarette types in a variety (4) of short-term genotoxicity assays.
Why was it done?
No such comparative study of cigarette smoke condensates has been reported. H...

Evaluation of genotoxic effects of surface waters using a battery of bioassays indicating different mode of action.

PubMed

Han, Yingnan; Li, Na; Oda, Yoshimitsu; Ma, Mei; Rao, Kaifeng; Wang, Zijian; Jin, Wei; Hong, Gang; Li, Zhiguo; Luo, Yi

2016-11-01

With the burgeoning contamination of surface waters threatening human health, the genotoxic effects of surface waters have received much attention. Because mutagenic and carcinogenic compounds in water cause tumors by different mechanisms, a battery of bioassays that each indicate a different mode of action (MOA) is required to evaluate the genotoxic effects of contaminants in water samples. In this study, 15 water samples from two source water reservoirs and surrounding rivers in Shijiazhuang city of China were evaluated for genotoxic effects. Target chemical analyses of 14 genotoxic pollutants were performed according to the Environmental quality standards for surface water of China. Then, the in vitro cytokinesis-block micronucleus (CBMN) assay, based on a high-content screening technique, was used to detect the effect of chromosome damage. The SOS/umu test using strain TA1535/pSK1002 was used to detect effects on SOS repair of gene expression. Additionally, two other strains, NM2009 and NM3009, which are highly sensitive to aromatic amines and nitroarenes, respectively, were used in the SOS/umu test to avoid false negative results. In the water samples, only two of the genotoxic chemicals listed in the water standards were detected in a few samples, with concentrations that were below water quality standards. However, positive results for the CBMN assay were observed in two river samples, and positive results for the induction of umuC gene expression in TA1535/pSK1002 were observed in seven river samples. Moreover, positive results were observed for NM2009 with S9 and NM3009 without S9 in some samples that had negative results using the strain TA1535/pSK1002. Based on the results with NM2009 and NM3009, some unknown or undetected aromatic amines and nitroarenes were likely in the source water reservoirs and the surrounding rivers. Furthermore, these compounds were most likely the causative pollutants for the genotoxic effect of these water samples. Therefore, to identify causative pollutants with harmful biological effects, chemical analyses for the pollutants listed in water quality standards is not sufficient, and single-endpoint bioassays may underestimate adverse effects. Thus, a battery of bioassays based on different MOAs is required for the comprehensive detection of harmful biological effects. In conclusion, for genotoxicity screening of surface waters, the SOS/umu test system by using different strains combined with the CBMN assay was a useful approach. Copyright © 2016 Elsevier Inc. All rights reserved.

Protective effect of boric acid on lead- and cadmium-induced genotoxicity in V79 cells.

PubMed

Ustündağ, Aylin; Behm, Claudia; Föllmann, Wolfram; Duydu, Yalçin; Degen, Gisela H

2014-06-01

The toxic heavy metals cadmium (Cd) and lead (Pb) are important environmental pollutants which can cause serious damage to human health. As the metal ions (Cd(2+) and Pb(2+)) accumulate in the organism, there is special concern regarding chronic toxicity and damage to the genetic material. Metal-induced genotoxicity has been attributed to indirect mechanisms, such as induction of oxidative stress and interference with DNA repair. Boron is a naturally occurring element and considered to be an essential micronutrient, although the cellular activities of boron compounds remain largely unexplored. The present study has been conducted to evaluate potential protective effects of boric acid (BA) against genotoxicity induced by cadmium chloride (CdCl2) and lead chloride (PbCl2) in V79 cell cultures. Cytotoxicity assays (neutral red uptake and cell titer blue assay) served to determine suitable concentrations for subsequent genotoxicity assays. Chromosomal damage and DNA strand breaks were assessed by micronucleus tests and comet assays. Both PbCl2 and CdCl2 (at 3, 5 and 10 µM) were shown to induce concentration-dependent increases in micronucleus frequencies and DNA strand breaks in V79 cells. BA itself was not cytotoxic (up to 300 µM) and showed no genotoxic effects. Pretreatment of cells with low levels of BA (2.5 and 10 µM) was found to strongly reduce the genotoxic effects of the tested metals. Based on the findings of this in vitro study, it can be suggested that boron provides an efficient protection against the induction of DNA strand breaks and micronuclei by lead and cadmium. Further studies on the underlying mechanisms for the protective effect of boron are needed.

Genotoxicity of the disinfection by-products resulting from peracetic acid- or hypochlorite-disinfected sewage wastewater.

PubMed

Crebelli, R; Conti, L; Monarca, S; Feretti, D; Zerbini, I; Zani, C; Veschetti, E; Cutilli, D; Ottaviani, M

2005-03-01

Wastewater disinfection is routinely carried out to prevent the spread of human pathogens present in wastewater effluents. To this aim, chemical and physical treatments are applied to the effluents before their emission in water bodies. In this study, the influence of two widely used disinfectants, peracetic acid (PAA) and sodium hypochlorite (NaClO), on the formation of mutagenic by-products was investigated. Wastewater samples were collected before and after disinfection, in winter and in summer, at a pilot plant installed in a municipal wastewater-treatment plant. Samples were adsorbed using silica C18 cartridges and the concentrates were tested for mutagenicity in the Salmonella typhimurium reversion test with strains TA98 and TA100. Non-concentrated water samples were tested with two plant genotoxicity assays (the Allium cepa root anaphase aberration test and the Tradescantia/micronucleus test). Mutagenicity assays in bacteria and in Tradescantia showed borderline mutagenicity in some of the wastewater samples, independent of the disinfection procedure applied. Negative results were obtained in the A. cepa anaphase aberration test. These results indicate that, in the conditions applied, wastewater disinfection with PAA and NaClO does not lead to the formation of significant amounts of genotoxic by-products.

Nandrolone androgenic hormone presents genotoxic effects in different cells of mice.

PubMed

do Carmo, Carolina Almeida; Gonçalves, Álvaro Luiz Martini; Salvadori, Daisy Maria Fávero; Maistro, Edson Luis

2012-10-01

Nandrolone is an androgenic-anabolic steroid (AAS) with diverse medical applications but taken indiscriminately by some to rapidly increase muscle mass. The aim of this study was to evaluate the genotoxic and clastogenic potential of nandrolone (deca-durabolin®) in vivo in different cells of mice, using the comet assay and micronucleus test, respectively. The animals received subcutaneous injection of the three doses of the steroid (1.0, 2.5 and 5.0 mg kg⁻¹ body weight). Cytotoxicity was assessed by scoring 200 consecutive total polychromatic (PCE) and normochromatic (NCE) erythrocytes (PCE-NCE ratio). The results showed a significant dose-related increase in the frequency of DNA damage in leukocytes, liver, bone marrow, brain and testicle cells at the three tested doses and a significant increase of the micronucleated polychromatic erythrocytes at all tested doses. Under our experimental conditions, the nandrolone steroid hormone showed genotoxic and clastogenic effects when administered subcutaneously to mice. Copyright © 2011 John Wiley & Sons, Ltd.

Cytogenetic analyses of Azadirachtin reveal absence of genotoxicity but marked antiproliferative effects in human lymphocytes and CHO cells in vitro.

PubMed

Mosesso, Pasquale; Bohm, Lothar; Pepe, Gaetano; Fiore, Mario; Carpinelli, Alice; Gäde, Gerd; Nagini, Siddavaram; Ottavianelli, Alessandro; Degrassi, Francesca

2012-09-18

In this work we have examined the genotoxic potential of the bioinsecticide Azadirachtin A (AZA) and its influence on cell proliferation on human lymphocytes and Chinese Hamster ovary (CHO) cells. AZA genotoxicity was assessed by the analysis of chromosomal aberrations and sister chromatid exchanges (SCEs) in the absence and presence of rat liver S9 metabolism. Primary DNA damage was also investigated by means of the comet assay. The results obtained clearly indicate that AZA is not genotoxic in mammalian cells. On the other hand, AZA proved to interfere with cell cycle progression as shown by modulation of frequencies of first (M1) and second division (M2) metaphases detected by 5-Bromo-2'-deoxyuridine labeling. Accumulation of M1 metaphases were more pronounced in human lymphocytes. In the transformed CHO cell line, however, significant increases of multinucleated interphases and polyploid cells were observed at long treatment time. At higher dose-levels, the incidence of polyploidy was close to 100%. Identification of spindle structure and number of centrosomes by fluorescent immunostaining with α- and γ-tubulin antibodies revealed aberrant mitoses exhibiting multipolar spindles with several centrosomal signals. These findings suggest that AZA can act either through a stabilizing activity of microtubules or by inhibition of Aurora A, since both mechanisms are able to generate genetically unstable polyploid cells with multipolar spindles and multinucleated interphases. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Micronucleated Erythrocytes in Peripheral Blood from Neonate Rats Exposed by Breastfeeding to Cyclophosphamide, Colchicine, or Cytosine-Arabinoside.

PubMed

Gómez-Meda, Belinda C; Bañales-Martínez, Luis R; Zamora-Perez, Ana L; Lemus-Varela, María de Lourdes; Trujillo, Xóchitl; Sánchez-Parada, María G; Torres-Mendoza, Blanca M; Armendáriz-Borunda, Juan; Zúñiga-González, Guillermo M

2016-01-01

Genotoxic exposure to chemical substances is common, and nursing mothers could transmit harmful substances or their metabolites to their offspring through breast milk. We explored the possibility of determining genotoxic effects in the erythrocytes of breastfeeding rat pups whose mothers received a genotoxic compound while nursing. Ten groups of female rats and five pups per dam were studied. The control group received sterile water, and the experimental groups received one of three different doses of cyclophosphamide, colchicine, or cytosine-arabinoside. Blood smears were prepared from samples taken from each dam and pup every 24 h for six days. There were increased numbers of micronucleated erythrocytes (MNEs) and micronucleated polychromatic erythrocytes (MNPCEs) in the samples from pups in the experimental groups ( P < 0.02) and increased MNPCE frequencies in the samples from the dams ( P < 0.05). These results demonstrate the vertical transmission of the genotoxic effect of the compounds tested. In conclusion, assessing MNEs in breastfeeding neonate rats to assess DNA damage may be a useful approach for identifying genotoxic compounds and/or cytotoxic effects. This strategy could help in screening for therapeutic approaches that are genotoxic during the lactation stage and these assessments might also be helpful for developing preventive strategies to counteract harmful effects.

Micronucleated Erythrocytes in Peripheral Blood from Neonate Rats Exposed by Breastfeeding to Cyclophosphamide, Colchicine, or Cytosine-Arabinoside

PubMed Central

Bañales-Martínez, Luis R.; Lemus-Varela, María de Lourdes; Trujillo, Xóchitl; Sánchez-Parada, María G.; Armendáriz-Borunda, Juan; Zúñiga-González, Guillermo M.

2016-01-01

Genotoxic exposure to chemical substances is common, and nursing mothers could transmit harmful substances or their metabolites to their offspring through breast milk. We explored the possibility of determining genotoxic effects in the erythrocytes of breastfeeding rat pups whose mothers received a genotoxic compound while nursing. Ten groups of female rats and five pups per dam were studied. The control group received sterile water, and the experimental groups received one of three different doses of cyclophosphamide, colchicine, or cytosine-arabinoside. Blood smears were prepared from samples taken from each dam and pup every 24 h for six days. There were increased numbers of micronucleated erythrocytes (MNEs) and micronucleated polychromatic erythrocytes (MNPCEs) in the samples from pups in the experimental groups (P < 0.02) and increased MNPCE frequencies in the samples from the dams (P < 0.05). These results demonstrate the vertical transmission of the genotoxic effect of the compounds tested. In conclusion, assessing MNEs in breastfeeding neonate rats to assess DNA damage may be a useful approach for identifying genotoxic compounds and/or cytotoxic effects. This strategy could help in screening for therapeutic approaches that are genotoxic during the lactation stage and these assessments might also be helpful for developing preventive strategies to counteract harmful effects. PMID:28018917

Occurrence and Control of Genotoxins in Drinking Water: A Monitoring Proposal.

PubMed

Ceretti, Elisabetta; Moretti, Massimo; Zerbini, Ilaria; Villarini, Milena; Zani, Claudia; Monarca, Silvano; Feretti, Donatella

2016-12-09

Many studies have shown the presence of numerous organic genotoxins and carcinogens in drinking water. These toxic substances derive not only from pollution, but also from the disinfection treatments, particularly when water is obtained from surface sources and then chlorinated. Most of the chlorinated compounds in drinking water are nonvolatile and are difficult to characterize. Thus, it has been proposed to study such complex mixtures using short-term genotoxicity tests predictive of carcinogenic activity. Mutagenicity of water before and after disinfection has mainly been studied by the Salmonella/microsome (Ames test); in vitro genotoxicity tests have also been performed in yeasts and mammalian cells; in situ monitoring of genotoxins has also been performed using complete organisms such as aquatic animals or plants (in vivo). The combination of bioassay data together with results of chemical analyses would give us a more firm basis for the assessment of human health risks related to the consumption of drinking water. Tests with different genetic end-points complement each other with regard to sensitivity toward environmental genotoxins and are useful in detecting low genotoxicity levels which are expected in drinking water samples.

"Aspartame: A review of genotoxicity data".

PubMed

Kirkland, David; Gatehouse, David

2015-10-01

Aspartame is a methyl ester of a dipeptide of aspartic acid and phenylalanine. It is 200× sweeter than sucrose and is approved for use in food products in more than 90 countries around the world. Aspartame has been evaluated for genotoxic effects in microbial, cell culture and animal models, and has been subjected to a number of carcinogenicity studies. The in vitro and in vivo genotoxicity data available on aspartame are considered sufficient for a thorough evaluation. There is no evidence of induction of gene mutations in a series of bacterial mutation tests. There is some evidence of induction of chromosomal damage in vitro, but this may be an indirect consequence of cytotoxicity. The weight of evidence from in vivo bone marrow micronucleus, chromosomal aberration and Comet assays is that aspartame is not genotoxic in somatic cells in vivo. The results of germ cell assays are difficult to evaluate considering limited data available and deviations from standard protocols. The available data therefore support the conclusions of the European Food Safety Authority (EFSA) that aspartame is non-genotoxic. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

Mixture genotoxicity of 2,4-dichlorophenoxyacetic acid, acrylamide, and maleic hydrazide on human Caco-2 cells assessed with comet assay.

PubMed

Syberg, Kristian; Binderup, Mona-Lise; Cedergreen, Nina; Rank, Jette

2015-01-01

Assessment of genotoxic properties of chemicals is mainly conducted only for single chemicals, without taking mixture genotoxic effects into consideration. The current study assessed mixture effects of the three known genotoxic chemicals, 2,4-dichlorophenoxyacetic acid (2,4-D), acrylamide (AA), and maleic hydrazide (MH), in an experiment with a fixed ratio design setup. The genotoxic effects were assessed with the single-cell gel electrophoresis assay (comet assay) for both single chemicals and the ternary mixture. The concentration ranges used were 0-1.4, 0-20, and 0-37.7 mM for 2,4-D, AA, and MH, respectively. Mixture toxicity was tested with a fixed ratio design at a 10:23:77% ratio for 2.4-D:AA:MH. Results indicated that the three chemicals yielded a synergistic mixture effect. It is not clear which mechanisms are responsible for this interaction. A few possible interactions are discussed, but further investigations including in vivo studies are needed to clarify how important these more-than-additive effects are for risk assessment.

Genotoxicity of soil from farmland irrigated with wastewater using three plant bioassays.

PubMed

Cabrera, G L; Rodriguez, D M

1999-05-19

Three well known plant bioassays, the Allium root chromosome aberration (AL-RAA) assay, the Tradescantia micronucleus (Trad-MCN) assay, and the Tradescantia stamen hair (Trad-SHM) mutation assay were validated in 1991 by the International Programme on Chemical Safety (IPCS) under the auspices of the World Health Organization, and the United Nations Environment Programme (UNEP). These plant bioassays have proven to be efficient tests for chemical screening and especially for in situ monitoring for genotoxicity of environmental pollutants. As a result of this validation study, standard protocols of these three plant bioassays were used by some of the 11 participating countries in the IPCS to carry on genotoxicity tests on air, water and soil as a follow up activity. In the city of Queretaro, Mexico, wastewater coming from both industrial and domestic sources and without any treatment is used to irrigate the farm crops, polluting the soil. Potentially the pollutants could reach the food chain. For the above reason, soil irrigated with wastewater was sampled and monitored for the presence of genotoxic agents using the above three bioassays. Extracts from soil samples were made using distilled water and organic solvents by shaking the sample for about 12 h under a relatively low temperature (15-20 degrees C). Plant cuttings of Tradescantia or the roots of Allium were treated by submerging them in the extracts. Three replicates of each sample were analyzed in each of the three bioassays. Extracts using DMSO, ethanol and distilled water tested positive in the three bioassays and there were no differences for the genotoxicity of the extracts with the different solvents. Copyright 1999 Elsevier Science B.V.

Effects of seven chemicals on DNA damage in the rat urinary bladder: a comet assay study.

PubMed

Wada, Kunio; Yoshida, Toshinori; Takahashi, Naofumi; Matsumoto, Kyomu

2014-07-15

The in vivo comet assay has been used for the evaluation of DNA damage and repair in various tissues of rodents. However, it can give false-positive results due to non-specific DNA damage associated with cell death. In this study, we examined whether the in vivo comet assay can distinguish between genotoxic and non-genotoxic DNA damage in urinary bladder cells, by using the following seven chemicals related to urinary bladder carcinogenesis in rodents: N-butyl-N-(4-hydroxybutyl)nitrosamine (BBN), glycidol, 2,2-bis(bromomethyl)-1,3-propanediol (BMP), 2-nitroanisole (2-NA), benzyl isothiocyanate (BITC), uracil, and melamine. BBN, glycidol, BMP, and 2-NA are known to be Ames test-positive and they are expected to produce DNA damage in the absence of cytotoxicity. BITC, uracil, and melamine are Ames test-negative with metabolic activation but have the potential to induce non-specific DNA damage due to cytotoxicity. The test chemicals were administered orally to male Sprague-Dawley rats (five per group) for each of two consecutive days. Urinary bladders were sampled 3h after the second administration and urothelial cells were analyzed by the comet assay and subjected to histopathological examination to evaluate cytotoxicity. In the urinary bladders of rats treated with BBN, glycidol, and BMP, DNA damage was detected. In contrast, 2-NA induced neither DNA damage nor cytotoxicity. The non-genotoxic chemicals (BITC, uracil, and melamine) did not induce DNA damage in the urinary bladders under conditions where some histopathological changes were observed. The results indicate that the comet assay could distinguish between genotoxic and non-genotoxic chemicals and that no false-positive responses were obtained. Copyright © 2014 Elsevier B.V. All rights reserved.

Photolytic fate and genotoxicity of benzophenone-derived compounds and their photodegradation mixtures in the aqueous environment.

PubMed

Kotnik, Kristina; Kosjek, Tina; Žegura, Bojana; Filipič, Metka; Heath, Ester

2016-03-01

This study investigates the environmental fate of eight benzophenone derivatives (the pharmaceutical ketoprofen, its phototransformation products 3-ethylbenzophenone and 3-acetylbenzophenone, and five benzophenone-type UV filters) by evaluating their photolytic behaviour. In addition, the genotoxicity of these compounds and the produced photodegradation mixtures was studied. Laboratory-scale irradiation experiments using a medium pressure UV lamp revealed that photodegradation of benzophenones follows pseudo-first-order kinetics. Ketoprofen was the most photolabile (t1/2 = 0.8 min), while UV filters were more resistant to UV light with t1/2 between 17 and 99 h. The compounds were also exposed to irradiation by natural sunlight and showed similar photostability as predicted under laboratory conditions. Solar photodegradation experiments were performed in distilled water, lake and seawater, and revealed that photosensitizers present in natural waters significantly affect the photolytic behaviour of the investigated compounds. In this case, the presence of lake water resulted in accelerated photodecomposition, while seawater showed different effects on photodegradation, depending on a compound. Further, it was shown that the transformation products of ketoprofen 3-ethylbenzophenone and 3-acetylbenzophenone were formed under environmental conditions when ketoprofen was exposed to natural sunlight. Genotoxicity testing of parent benzophenone compounds using the SOS/umuC assay revealed that UV filters exhibited weak genotoxic activity in the presence of a metabolic activation system, however the concentrations tested were much higher than found in the environment (≥125 μg mL(-1)). After irradiation of benzophenones, the produced photodegradation mixtures showed that, with the exception of benzophenone that exhibited weak genotoxic activity, all the other compounds tested did not elicit any activity when exposed to UV light. Copyright © 2015 Elsevier Ltd. All rights reserved.

In vitro and in vivo genotoxicity assessment of HI-6 dimethanesulfonate/oxime.

PubMed

Nakab, Lauren; Bardot, Isabelle; Bardot, Sébastien; Simar, Sophie; Marzin, Daniel; Nesslany, Fabrice

2014-03-01

Organophosphate compounds, which induce organophosphate poisoning, were originally used as pesticides. But this type of product has also been used as warfare nerve agent like sarin, soman, Russian VX, or tabun. HI-6-dimethanesulfonate is a salt of the oxime HI-6 used in the treatment of nerve-agent poisoning. It is known to be the best re-activator component of inactivated acetyl cholinesterase. HI-6-dimethanesulfonate has shown a higher level of solubility with similar potency to reactivate acetyl cholinesterase and a similar pharmacokinetics profile compared with HI-6 dichloride. HI-6 dimethanesulfonate was tested for its mutagenic and genotoxic potential by use of the standard ICH S2R (1) battery for the evaluation of pharmaceuticals. HI-6-dimethanesulfonate was mutagenic in the Ames test only in the presence of metabolic activation. In the mutation assay at the Tk locus in L5178Y mouse-lymphoma cells, HI-6-dimethanesulfonate showed mutagenic activity both with and without metabolic activation, with a significant increase in small colonies. The effects were in favour of a clastogenic activity. It was concluded that the compound was mutagenic and possibly clastogenic in vitro. In contrast, the in vivo micronucleus test in rat bone-marrow did not demonstrate any genotoxic activity and the Comet assay performed in rat liver did not show any statistically or biologically significant increases in DNA strand-breaks. The results of both in vivo studies performed on two different organs with two endpoints are sufficient to conclude the absence of a genotoxic hazard in vivo and to consider that there is no genotoxic concern in humans for HI-6-dimethanesulfonate. Copyright © 2014 Elsevier B.V. All rights reserved.

UPLC-MS/MS analysis of antibiotics in pharmaceutical effluent in Tunisia: ecotoxicological impact and multi-resistant bacteria dissemination.

PubMed

Tahrani, Leyla; Mehri, Ines; Reyns, Tim; Anthonissen, Roel; Verschaeve, Luc; Khalifa, Anis Bel Haj; Loco, Joris Van; Abdenaceur, Hassen; Mansour, Hedi Ben

2018-05-01

The UPLC MS/MS analysis showed the presence of the two antibiotics in the pharmaceutical industry discharges during 3 months; norfloxacin and spiramycin which were quantified with the mean concentrations of 226.7 and 84.2 ng mL -1 , respectively. Sixteen resistant isolates were obtained from the pharmaceutical effluent and identified by sequencing. These isolates belong to different genera, namely Citrobacter, Acinetobacter, Pseudomonas, Delftia, Shewanella, and Rheinheimera. The antibiotic resistance phenotypes of these isolates were determined (27 tested antibiotics-discs). All the studied isolates were found resistant to amoxicillin and gentamicin, and 83.33% of isolates were resistant to ciprofloxacin. Multiple antibiotic resistances were revealed against β-lactams, quinolones, and aminoglycosides families. Our overall results suggest that the obtained bacterial isolates may constitute potential candidates for bioremediation and can be useful for biotechnological applications. Genotoxic effects were assessed by a battery of biotests; the pharmaceutical wastewater was genotoxic according to the bacterial Vitotox test and micronuclei test. Genotoxicity was also evaluated by the comet test; the tail DNA damages reached 38 and 22% for concentrated sample (10×) and non-concentrated sample (1×), respectively. However, the histological sections of kidney and liver's mice treated by pharmaceutical effluent showed normal histology and no visible structural effects or alterations as cytolysis, edema, or ulcerative necrosis were observed. Residual antibiotics can reach water environment through wastewater and provoke dissemination of the antibiotics resistance and induce genotoxic effects.

Tests for genotoxicity and mutagenicity of furan and its metabolite cis-2-butene-1,4-dial in L5178Y tk+/- mouse lymphoma cells.

PubMed

Kellert, Marco; Brink, Andreas; Richter, Ingrid; Schlatter, Josef; Lutz, Werner K

2008-12-08

Furan is found in various food items and is cytotoxic and carcinogenic in the liver of rats and mice. Metabolism of furan includes the formation of an unsaturated dialdehyde, cis-2-butene-1,4-dial (BDA). In view of the multifunctional electrophilic reactivity of BDA, adduct formation with protein and DNA may explain some of the toxic effects. Short-term tests for genotoxicity of furan in mammalian cells are inconclusive, little is known for BDA. We investigated BDA generated by hydrolysis of 2,5-diacetoxy-2,5-dihydrofuran for genotoxicity in L5178Y tk+/- mouse lymphoma cells using standard procedures for the comet assay, the micronucleus test, and the mouse lymphoma thymidine kinase gene mutation assay, using 4-h incubation periods. Cytotoxicity was remarkable: cell viability at concentrations>or=50 microM was reduced to <50%. In the dose range up to 25 microM, viability was >90%. Measures of comet-tail length and thymidine-kinase mutant frequency were increased 1.6- and 2.4-fold above control, respectively. Analysis of three fully independent replicates with a linear mixed-effects model showed a highly significant increase with concentration for both endpoints. Compared to methyl methanesulfonate used as a positive control, BDA was of similar potency with respect to genotoxicity, but it was much more cytotoxic. Furan added to cell cultures at doses that resulted in time-averaged effective concentrations of up to 3100 microM was neither cytotoxic nor genotoxic. A potential cross-linking activity of BDA was investigated by checking whether gamma radiation-induced DNA migration in the comet assay could be reduced by pre-treatment with BDA. In contrast to the effect of the positive control glutaraldehyde, BDA treatment did not reduce the comet tail length. On the contrary, an increase was observed at >or=100 microM BDA, which was attributable to early apoptotic cells. Although BDA was found to be a relatively potent genotoxic agent in terms of the concentration necessary to double the background measures, cytotoxicity strongly limited the concentration range that produced interpretable results. This may explain some of the inconclusive results and indicates that non-genotoxic effects must be taken into account in the discussion of the modes of toxic and carcinogenic action of furan.

IWGT report on quantitative approaches to genotoxicity risk assessment II. Use of point-of-departure (PoD) metrics in defining acceptable exposure limits and assessing human risk

EPA Science Inventory

This is the second of two reports from the International Workshops on Genotoxicity Testing (IWGT) Working Group on Quantitative Approaches to Genetic Toxicology Risk Assessment (the QWG). The first report summarized the discussions and recommendations of the QWG related to the ne...

On the relevance of genotoxicity for fish populations I: effects of a model genotoxicant on zebrafish (Danio rerio) in a complete life-cycle test.

PubMed

Diekmann, Markus; Hultsch, Veit; Nagel, Roland

2004-05-28

Genotoxicity may be detected in surface waters by means of various genotoxicity assays. In order to enable an ecotoxicological assessment of the consequences of such genotoxic potential for fish populations, a complete life-cycle test with zebrafish (Danio rerio) and the model genotoxicant 4-nitroquinoline-1-oxide (NQO) was conducted. Zebrafish (f1) were continuously exposed to NQO (i.e. 0.1, 0.3, 1.1, 2.9, and 14.6 microg/l, respectively) from fertilised eggs until sexual maturity. In addition to reproduction studies in the f1-generation, f2-fish were exposed to NQO during the first 6 weeks of development. Up to 2.9 microg/l NQO, fish did not display differences in survival and growth (P < 0.05). A NQO concentration of 14.6 microg/l, however, was lethal. Female fish exposed to all NQO concentrations up to 2.9 microg/l displayed a significant reduction in egg production (P < 0.05). A mathematical simulation revealed that exposure to weak concentrations of NQO is leading to an elevated extinction risk. Copyright 2004 Elsevier B.V.

Seahorse (Hippocampus reidi) as a bioindicator of crude oil exposure.

PubMed

Delunardo, Frederico Augusto Cariello; de Carvalho, Luciano Rodrigues; da Silva, Bruno Ferreira; Galão, Michel; Val, Adalberto Luís; Chippari-Gomes, Adriana R

2015-07-01

This study explored the suitability of the seahorse Hippocampus reidi (Ginsburg, 1933) for assessing biomarkers of genotoxic effects and its use as a sentinel organism to detect the effects of acute exposure to petroleum hydrocarbons. Fish were exposed to three concentrations of crude oil (10, 20 and 30 g/kg) for 96 h, and the activity of phase II biotransformation enzyme glutathione S-transferase (GST) was measured. In addition, we performed genotoxicity assays, such as comet assay, micronucleus (MN) test and nuclear abnormalities (NA) induction, on the erythrocytes of the fish species. Our results revealed that the inhibition of hepatic GST activity in H. reidi was dependent on increasing crude oil concentrations. In contrast, an increase in the damage index (DI) and MN frequency were observed with increased crude oil concentrations. These results indicate that the alkaline comet assay and micronucleus test were suitable and useful in the evaluation of the genotoxicity of crude oil, which could improve determinations of the impact of oil spills on fish populations. In addition, H. reidi is a promising "sentinel organism" to detect the genotoxic impact of petroleum hydrocarbons. Copyright © 2015 Elsevier Inc. All rights reserved.

Risk assessment of petroleum-contaminated soil using soil enzyme activities and genotoxicity to Vicia faba.

PubMed

Ma, Jun; Shen, Jinglong; Liu, Qingxing; Fang, Fang; Cai, Hongsheng; Guo, Changhong

2014-05-01

Pollution caused by petroleum is one of the most serious problems worldwide. To better understand the toxic effects of petroleum-contaminated soil on the microflora and phytocommunity, we conducted a comprehensive field study on toxic effects of petroleum contaminated soil collected from the city of Daqing, an oil producing region of China. Urease, protease, invertase, and dehydrogenase activity were significantly reduced in microflora exposed to contaminated soils compared to the controls, whereas polyphenol oxidase activity was significantly increased (P < 0.05). Soil pH, electrical conductivity, and organic matter content were correlated with total petroleum hydrocarbons (TPHs) and a correlation (P < 0.01) existed between the C/N ratio and TPHs. Protease, invertase and catalase were correlated with TPHs. The Vicia faba micronucleus (MN) test, chromosome aberrant (CA) analyses, and the mitotic index (MI) were used to detect genotoxicity of water extracts of the soil. Petroleum-contaminated samples indicated serious genotoxicity to plants, including decreased index level of MI, increased frequency of MN and CA. The combination of enzyme activities and genotoxicity test via Vicia faba can be used as an important indicator for assessing the impact of TPH on soil ecosystem.

Effects of artichoke (Cynara scolymus) leaf and bloom head extracts on chemically induced DNA lesions in Drosophila melanogaster

PubMed Central

Jacociunas, Laura Vicedo; Dihl, Rafael Rodrigues; Lehmann, Mauricio; de Barros Falcão Ferraz, Alexandre; Richter, Marc François; da Silva, Juliana; de Andrade, Heloísa Helena Rodrigues

2014-01-01

The genotoxicity of bloom head (BHE) and leaf (LE) extracts from artichoke (Cynara scolymus L.), and their ability to modulate the mutagenicity and recombinogenicity of two alkylating agents (ethyl methanesulfonate – EMS and mitomycin C – MMC) and the intercalating agent bleomycin (BLM), were examined using the somatic mutation and recombination test (SMART) in Drosophila melanogaster. Neither the mutagenicity nor the recombinogenicity of BLM or MMC was modified by co- or post-treatment with BHE or LE. In contrast, co-treatment with BHE significantly enhanced the EMS-induced genotoxicity involving mutagenic and/or recombinant events. Co-treatment with LE did not alter the genotoxicity of EMS whereas post-treatment with the highest dose of LE significantly increased this genotoxicity. This enhancement included a synergistic increase restricted to somatic recombination. These results show that artichoke extracts promote homologous recombination in proliferative cells of D. melanogaster. PMID:24688296

Effects of artichoke (Cynara scolymus) leaf and bloom head extracts on chemically induced DNA lesions in Drosophila melanogaster.

PubMed

Jacociunas, Laura Vicedo; Dihl, Rafael Rodrigues; Lehmann, Mauricio; de Barros Falcão Ferraz, Alexandre; Richter, Marc François; da Silva, Juliana; de Andrade, Heloísa Helena Rodrigues

2014-03-01

The genotoxicity of bloom head (BHE) and leaf (LE) extracts from artichoke (Cynara scolymus L.), and their ability to modulate the mutagenicity and recombinogenicity of two alkylating agents (ethyl methanesulfonate - EMS and mitomycin C - MMC) and the intercalating agent bleomycin (BLM), were examined using the somatic mutation and recombination test (SMART) in Drosophila melanogaster. Neither the mutagenicity nor the recombinogenicity of BLM or MMC was modified by co- or post-treatment with BHE or LE. In contrast, co-treatment with BHE significantly enhanced the EMS-induced genotoxicity involving mutagenic and/or recombinant events. Co-treatment with LE did not alter the genotoxicity of EMS whereas post-treatment with the highest dose of LE significantly increased this genotoxicity. This enhancement included a synergistic increase restricted to somatic recombination. These results show that artichoke extracts promote homologous recombination in proliferative cells of D. melanogaster.

Evaluation of genotoxic and cytotoxic properties of pesticides employed in Italian agricultural practices.

PubMed

De Marco, A; De Salvia, R; Polani, S; Ricordy, R; Sorrenti, F; Perticone, P; Cozzi, R; D'Ambrosio, C; De Simone, C; Guidotti, M; Albanesi, T; Duranti, G; Festa, F; Gensabella, G; Owczarek, M

2000-07-01

In a program coordinated by the Italian Ministry of Works, we tested in vitro four pesticides widely employed in a developed agricultural region of central Italy. The four commercial agents were chosen on the basis of their diffusion in agricultural practice, knowledge of their active principle(s), and scant availability of data concerning their toxic and genotoxic activity. The agents were Cirtoxin, Decis, Tramat Combi (TC), and Lasso Micromix (LM). All substances were tested in three in vitro systems: Chinese hamster ovary (CHO) cells, a metabolically competent hamster cell line (Chinese hamster epithelial liver; CHEL), and root tips of Vicia faba (VF). The cytotoxic and genotoxic end points challenged were micronuclei and root tip length (RTL) in VF and mitotic index (MI), proliferation index (PI), cell survival (CS), cell growth (CG), cell cycle length (CCL), sister chromatid exchanges, chromosomal aberrations, and single-cell gel electrophoresis, or comet assay, in CHEL and CHO cells. Tested doses ranged from the field dose up to 200x the field dose to take into account accumulation effects. On the whole, tested agents appear to induce genotoxic damage only at subtoxic or toxic doses, indicating a low clastogenic risk. MI, PI, CS, CG, RTL, and CCL appear to be the less sensitive end points, showing no effects in the presence of a clear positive response in some or all of the other tests. Using cytogenetic tests, we obtained positive results for TC and LM treatments in CHO but not in CHEL cells. These data could be accounted for by postulating a detoxifying activity exerted by this cell line. However, cytogenetic end points appear to be more sensitive than those referring to cytotoxicity.

[Cytotoxicity and genotoxicity of drinking water of two networks supplied by surface water].

PubMed

Pellacani, Claudia; Branchi, Elisa; Buschini, Annamaria; Furlini, Mariangela; Poli, Paola; Rossi, Carlo

2005-01-01

Evaluation of cytotoxic and genotoxic load of drinking water in relationship to the source of supplies, the disinfection process, and the piping system. Two treatment/distribution networks of drinking water, the first (#1) located near the source, the second (#2) located near the mouth of a river supplying the plants. Water samples were collected before (F) and after (A) the disinfection process and in two points (R1 and R2) of the piping system. The samples, concentrated on C18, were tested for DNA damage in human leukocytes by the Comet assay and for gene conversion, reversion and mitochondrial mutability in Saccharomyces cerevisiae D7 strain. The approach used in this study is able to identify genotoxic compounds at low concentration and evaluate their antagonism/synergism in complex mixtures. Comet assay results show that the raw water quality depends on the sampling point, suggesting that a high input of environmental pollutants occurred during river flowing; they also show that the disinfection process can both detoxify or enhance biological activity of raw water according to its quality and that the piping systems do not affect tap water cytotoxic/genotoxic load. The yeast tests indicate the presence of some disinfection by-products effective on mitochondrial DNA. The biological assays used in this study are proven to be able to detect the presence of low concentrations of toxic/genotoxic compounds and assess the sources of their origin/production.

Genotoxic and Antigenotoxic Potential of Momordica charantia Linn (Cucurbitaceae) in the Wing Spot Test of Drosophila melanogaster.

PubMed

Guterres, Zaira Rosa; Zanetti, Thalita Alves; Sennes-Lopes, Tiago Felipe; da Silva, Ana Francisca Gomes

2015-10-01

Momordica charantia, popularly known as bitter melon, is a plant widely used in ethnobotanical medicine. It has antibacterial, antifungal, anthelmintic, antidiabetic, antiviral, and antimalarial activities, among others. The goal of this study was to evaluate the genotoxic and/or antigenotoxic activity of the aqueous extracts obtained from the aerial parts and fruit of this plant by means of the Drosophila melanogaster wing spot test. Third-stage larvae that obtained standard (ST) cross and high bioactivation (HB) cross were treated with aqueous extracts of the aerial parts (IQA) and fruit (IQF) of M. charantia, following two protocols (genotoxicity and antigenotoxicity). The aqueous extracts are not genotoxic in lower concentrations. The frequencies of mutant spots observed in the descendants of the ST and HB crosses treated with doxorubicin (DXR) alone were 8.65 and 9.25, respectively, whereas in those cotreated with IQA and DXR, the frequencies ranged from 15.90 to 29 in the ST cross and from 15.05 to 24.78 in the HB cross. In cotreatment with IQF, the frequencies ranged from 30.10 to 30.65 in the ST cross and from 13.60 to 14.50 in the HB cross, whereas the frequencies obtained with DXR were 32.50 in the ST cross and 26.00 in the HB cross. In conclusion, the IQA has a synergistic effect, enhancing the genotoxicity of DXR in the ST cross and the HB cross, whereas the IQF has antigenotoxic effects in the HB cross.

In vivo genotoxicity evaluation of an artichoke (Cynara scolymus L.) aqueous extract.

PubMed

Zan, Meriele A; Ferraz, Alexandre B F; Richter, Marc F; Picada, Jaqueline N; de Andrade, Heloisa H R; Lehmann, Mauricio; Dihl, Rafael R; Nunes, Emilene; Semedo, Juliane; Da Silva, Juliana

2013-02-01

The Cynara scolymus (artichoke) is widely consumed as tea or food and shows important therapeutic properties. However, few studies have assessed the possible toxic effects of artichoke extracts. This study evaluates genotoxic and mutagenic activities of artichoke leaf aqueous extract in mice using the comet assay and the micronucleus test. Leaf extracts were given by gavage (500 mg/kg, 1000 mg/kg, and 2000 mg/kg) for 3 consecutive days. Extract composition was investigated using phytochemical screening and high-performance liquid chromatography (HPLC). In addition, antioxidant capacity was analyzed through the diphenyl-picrylhydrazyl (DPPH) and xanthine oxidase assay. Phytochemical screening detected the presence of phenolic compounds, flavonoids, and saponins. HPLC analyses indicated the presence of chlorogenic acid, caffeic acid, isoquercetrin, and rutin. Extracts showed a dose-dependent free radical scavenging effect of DPPH and an inhibitory effect of xanthine oxidase. The genotoxic results showed that leaf extracts did not increase micronuclei in peripheral blood cells. Compared to the control group, a significant increase in comet assay values was observed only in bone marrow of group treated with 2000 mg/kg, the highest dose tested, indicating that artichoke tea should be consumed with moderation. This is the first report of in vivo mutagenic and genotoxic evaluation with C. scolymus. The present study revealed leaf aqueous extract from artichoke shows lack of mutagenicity in vivo, and low genotoxicity and antioxidant activity; indicating that artichoke tea should be consumed with moderation. © 2013 Institute of Food Technologists®

Comparison of in vivo genotoxic and carcinogenic potency to augment mode of action analysis: Case study with hexavalent chromium.

PubMed

Thompson, Chad M; Bichteler, Anne; Rager, Julia E; Suh, Mina; Proctor, Deborah M; Haws, Laurie C; Harris, Mark A

2016-04-01

Recent analyses-highlighted by the International Workshops on Genotoxicity Testing Working Group on Quantitative Approaches to Genetic Toxicology Risk Assessment-have identified a correlation between (log) estimates of a carcinogen's in vivo genotoxic potency and in vivo carcinogenic potency in typical laboratory animal models, even when the underlying data have not been matched for tissue, species, or strain. Such a correlation could have important implications for risk assessment, including informing the mode of action (MOA) of specific carcinogens. When in vivo genotoxic potency is weak relative to carcinogenic potency, MOAs other than genotoxicity (e.g., endocrine disruption or regenerative hyperplasia) may be operational. Herein, we review recent in vivo genotoxicity and carcinogenicity data for hexavalent chromium (Cr(VI)), following oral ingestion, in relevant tissues and species in the context of the aforementioned correlation. Potency estimates were generated using benchmark doses, or no-observable-adverse-effect-levels when data were not amenable to dose-response modeling. While the ratio between log values for carcinogenic and genotoxic potency was ≥1 for many compounds, the ratios for several Cr(VI) datasets (including in target tissue) were less than unity. In fact, the ratios for Cr(VI) clustered closely with ratios for chloroform and diethanolamine, two chemicals posited to have non-genotoxic MOAs. These findings suggest that genotoxicity may not play a major role in the cancers observed in rodents following exposure to high concentrations of Cr(VI) in drinking water-a finding consistent with recent MOA and adverse outcome pathway (AOP) analyses concerning Cr(VI). This semi-quantitative analysis, therefore, may be useful to augment traditional MOA and AOP analyses. More case examples will be needed to further explore the general applicability and validity of this approach for human health risk assessment. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

Evaluation of genotoxicity and DNA protective effects of mangiferin, a glucosylxanthone isolated from Mangifera indica L. stem bark extract.

PubMed

Rodeiro, I; Hernandez, S; Morffi, J; Herrera, J A; Gómez-Lechón, M J; Delgado, R; Espinosa-Aguirre, J J

2012-09-01

Mangiferin is a glucosylxantone isolated from Mangifera indica L. stem bark. Several studies have shown its pharmacological properties which make it a promising candidate for putative therapeutic use. This study was focused to investigate the in vitro genotoxic effects of mangiferin in the Ames test, SOS Chromotest and Comet assay. The genotoxic effects in bone marrow erythrocytes from NMRI mice orally treated with mangiferin (2000 mg/kg) were also evaluated. Additionally, its potential antimutagenic activity against several mutagens in the Ames test and its effects on CYP1A1 activity were assessed. Mangiferin (50-5000 μg/plate) did not increased the frequency of reverse mutations in the Ames test, nor induced primary DNA damage (5-1000 μg/mL) to Escherichia coli PQ37 cells under the SOS Chromotest. It was observed neither single strand breaks nor alkali-labile sites in blood peripheral lymphocytes or hepatocytes after 1h exposition to 10-500 μg/mL of mangiferin under the Comet assay. Furthermore, micronucleus studies showed mangiferin neither induced cytotoxic activity nor increased the frequency of micronucleated/binucleated cells in mice bone marrow. In short, mangiferin did not induce cytotoxic or genotoxic effects but it protect against DNA damage which would be associated with its antioxidant properties and its capacity to inhibit CYP enzymes. Copyright © 2012 Elsevier Ltd. All rights reserved.

Cytotoxicity and genotoxicity evaluation of organochalcogens in human leucocytes: a comparative study between ebselen, diphenyl diselenide, and diphenyl ditelluride.

PubMed

Caeran Bueno, Diones; Meinerz, Daiane Francine; Allebrandt, Josiane; Waczuk, Emily Pansera; dos Santos, Danúbia Bonfanti; Mariano, Douglas Oscar Ceolin; Rocha, João Batista Teixeira

2013-01-01

Organochalcogens, particularly ebselen, have been used in experimental and clinical trials with borderline efficacy. (PhSe)2 and (PhTe)2 are the simplest of the diaryl dichalcogenides and share with ebselen pharmacological properties. In view of the concerns with the use of mammals in studies and the great number of new organochalcogens with potential pharmacological properties that have been synthesized, it becomes important to develop screening protocols to select compounds that are worth to be tested in vivo. This study investigated the possible use of isolated human white cells as a preliminary model to test organochalcogen toxicity. Human leucocytes were exposed to 5-50  μM of ebselen, (PhSe)2, or (PhTe)2. All compounds were cytotoxic (Trypan's Blue exclusion) at the highest concentration tested, and Ebselen was the most toxic. Ebselen and (PhSe)2 were genotoxic (Comet Assay) only at 50  μM, and (PhTe)2 at 5-50  μM. Here, the acute cytotoxicity did not correspond with in vivo toxicity of the compounds. But the genotoxicity was in the same order of the in vivo toxicity to mice. These results indicate that in vitro genotoxicity in white blood cells should be considered as an early step in the investigation of potential toxicity of organochalcogens.

The effect of particle size on the genotoxicity of gold nanoparticles.

PubMed

Xia, Qiyue; Li, Hongxia; Liu, Ying; Zhang, Shuyang; Feng, Qiyi; Xiao, Kai

2017-03-01

Despite the increasing biomedical applications of gold nanoparticles (AuNPs), their toxicological effects need to be thoroughly understood. In the present study, the genotoxic potential of commercially available AuNPs with varying size (5, 20, and 50 nm) were assessed using a battery of in vitro and in vivo genotoxicity assays. In the comet assay, 20 and 50 nm AuNPs did not induce obvious DNA damage in HepG2 cells at the tested concentrations, whereas 5 nm NPs induced a dose-dependent increment in DNA damage after 24-h exposure. Furthermore, 5 nm AuNPs induced cell cycle arrest in G1 phase in response to DNA damage, and promoted the production of reactive oxygen species (ROS). In the chromosomal aberration test, AuNPs exposure did not increase in the frequency of chromosomal aberrations in Chinese hamster lung (CHL) cells. In the standard in vivo micronucleus test, no obvious increase in the frequency of micronucleus formation was found in mice after 4 day exposure of AuNPs. However, when the exposure period was extended to 14 days, 5 nm AuNPs presented significant clastogenic damage, with a dose-dependent increase of micronuclei frequencies. This finding suggests that particle size plays an important role in determining the genotoxicity of AuNPs. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 710-719, 2017. © 2016 Wiley Periodicals, Inc.

Investigations on genotoxic effects of groundwater from the Mitterndorfer Senke and from the vicinity of Wiener Neustadt.

PubMed

Knasmüller, S; Helma, C; Eckl, P M; Gottmann, E; Steinkellner, H; Kassie, F; Haider, T; Parzefall, W; Schulte-Hermann, R

1998-12-11

This report describes the first study on genotoxic effects of Austrian ground- and drinking waters. Samples from the Mitterndorfer Senke (MS) and the vicinity of Wiener Neustadt were tested over a three years period. The MS is the largest aquifer in Austria. Due to deposition of industrial and community wastes, chemicals have polluted the groundwater in this area. Aim of the present study was to elucidate if consumption of these waters might pose a carcinogenic risk to humans. 43 Water samples were tested in a test battery which consisted of bacterial gene mutation assays (Salmonella strains TA100 and TA98), micronucleus (MN) assays with cultures of primary rat hepatocytes and plant bioassays (MN tests with Tradescantia and Vicia faba). For the bacterial assays, the water samples were extracted with XAD resins. In total, 27.9% of the samples caused positive effects; 8 samples were active in Salmonella microsome assays, Strain TA100 was particularly sensitive upon addition of metabolic activation mix (6 positive samples). Four samples were positive exclusively in MN assays with cultures of primary rat hepatocytes; one sample gave positive results in all three bioassays. Finished waters from waterworks were consistently devoid of mutagenic activity under all experimental conditions. Overall, only a small fraction of the groundwaters caused mutagenic effects and in all cases the activities were moderate. Comparison of the results of the present study with data obtained in other investigations under similar experimental conditions shows that the genotoxicity of groundwaters of the MS area are lower than the effects caused by ground- and drinking waters from other countries. The fact that no genotoxic activity was detected in any of the finished drinking waters can be taken as an indication that consumption of these waters does not pose a health hazard arising from contamination with genotoxic carcinogens to humans.

Genotoxic response of Austrian groundwater samples treated under standardized UV (254 nm)--disinfection conditions in a combination of three different bioassays.

PubMed

Haider, Thomas; Sommer, Regina; Knasmüller, Siefried; Eckl, Peter; Pribil, Walter; Cabaj, Alexander; Kundi, Michael

2002-01-01

Ground water samples from different geographic areas in Austria, with different amounts of natural and anthropogenic organic compounds were treated with a standardized low pressure UV (254 nm)-irradiation laboratory flow-through system (UV fluence: 800 J/m2). The genotoxic activities of the water samples before and after the UV disinfection were investigated using a combination of three different bioassays which complement each other with regard to their sensitivity detecting different genotoxins. The test battery comprises the Salmonella/microsome assay (Ames test with TA98. TA 100 and TA 102, with and without S9 mix) and two micronucleus tests with the plant Tradescantia (clone #4430) and with primary rat hepatocytes. Overall, the tested Austrian groundwater samples used for human consumption caused only weak genotoxic activities compared to drinking water samples reported from other countries under similar experimental conditions. With the exception of one weak positive result in the Ames test (only in strain TA98 without S9 mix) with an induction factor of 1.9) all samples after UV disinfection were devoid of additional mutagenic and clastogenic activities compared to the samples before UV disinfection.

Genotoxicity testing of sodium formononetin-3'-sulphonate (Sul-F) by assessing bacterial reverse mutation, chromosomal aberrations and micronucleus tests.

PubMed

Li, Chunmei; Gao, Yonglin; Wang, Yunzhi; Li, Guisheng; Fan, Xiaochen; Li, Yanshen; Guo, Chenghua; Tao, Jun

2017-06-01

As part of a safety evaluation, we evaluated the potential genotoxicity of sodium formononetin-3'-sulphonate (Sul-F) using bacterial reverse mutation assay, chromosomal aberrations detection, and mouse micronucleus test. In bacterial reverse mutation assay using five strains of Salmonella typhimurium (TA97, TA98, TA100, TA102 and TA1535), Sul-F (250, 500, 1000, 2000, 4000 μg/plate) did not increase the number of revertant colonies in any tester strain with or without S9 mix. In a chromosomal assay using Chinese hamster lung fibroblast (CHL) cells, there were no increases in either kind of aberration at any dose of Sul-F (400, 800, and 1600 μg/mL) treatment groups with or without S9 metabolic activation. In an in vivo bone marrow micronucleus test in ICR mice, Sul-F at up to 2000 mg/kg (intravenous injection) showed no significant increases in the incidence of micronucleated polychromatic erythrocytes, and the proportion of immature erythrocytes to total erythrocytes. The results demonstrated that Sul-F does not show mutagenic or genotoxic potential under these test conditions. Copyright © 2017. Published by Elsevier Inc.

Assessment of antimutagenic and genotoxic potential of senna (Cassia angustifolia Vahl.) aqueous extract using in vitro assays.

PubMed

Silva, C R; Monteiro, M R; Rocha, H M; Ribeiro, A F; Caldeira-de-Araujo, A; Leitão, A C; Bezerra, R J A C; Pádula, M

2008-02-01

Senna (Cassia angustifolia Vahl.) is widely used as a laxative, although potential side effects, such as toxicity and genotoxicity, have been reported. This study evaluated genotoxic and mutagenic effects of senna aqueous extract (SAE) by means of four experimental assays: inactivation of Escherichia coli cultures; bacterial growth inhibition; reverse mutation test (Mutoxitest) and DNA strand break analysis in plasmid DNA. Our results demonstrated that SAE produces single and double strand breaks in plasmid DNA in a cell free system. On the other hand, SAE was not cytotoxic or mutagenic to Escherichia coli strains tested. In effect, SAE was able to avoid H(2)O(2)-induced mutagenesis and toxicity in Escherichia coli IC203 (uvrA oxyR) and IC205 (uvrA mutM) strains, pointing to a new antioxidant/antimutagenic action of SAE.

Evaluation of toxicity of essential oils palmarosa, citronella, lemongrass and vetiver in human lymphocytes.

PubMed

Sinha, Sonali; Jothiramajayam, Manivannan; Ghosh, Manosij; Mukherjee, Anita

2014-06-01

The present investigation was undertaken to study the cytotoxic and genotoxic potential of the essential oils (palmarosa, citronella, lemongrass and vetiver) and monoterpenoids (citral and geraniol) in human lymphocytes. Trypan blue dye exclusion and MTT test was used to evaluate cytotoxicity. The genotoxicity studies were carried out by comet and DNA diffusion assays. Apoptosis was confirmed by Annexin/PI double staining. In addition, generation of reactive oxygen species was evaluated by DCFH-DA staining using flow cytometry. The results demonstrated that the four essential oils and citral induced cytotoxicity and genotoxicity at higher concentrations. The essential oils were found to induce oxidative stress evidenced by the generation of reactive oxygen species. With the exception of geraniol, induction of apoptosis was confirmed at higher concentrations of the test substances. Based on the results, the four essential oils are considered safe for human consumption at low concentrations. Copyright © 2014 Elsevier Ltd. All rights reserved.

Assessment of in vitro genotoxic and cytotoxic effects of flurbiprofen on human cultured lymphocytes.

PubMed

Timocin, Taygun; Ila, Hasan Basri; Dordu, Tuba; Husunet, Mehmet Tahir; Tazehkand, Mostafa Norizadeh; Valipour, Ebrahim; Topaktas, Mehmet

2016-01-01

Flurbiprofen is non-steroidal anti-inflammatory drug which is commonly used for its analgesic, antipyretic, and anti-inflammatory effects. The purpose of the study was to explore the genotoxic and cytotoxic effects of flurbiprofen in human cultured lymphocytes by sister chromatid exchange, chromosome aberration, and cytokinesis-blocked micronucleus tests. 10, 20, 30, and 40 μg/mL concentrations of flurbiprofen (solvent is DMSO) were used to treatment of human cultured lymphocytes at two different treatment periods (24 and 48 h). Flurbiprofen had no significant genotoxic effect in any of these tests. But exposing to flurbiprofen for 24 and 48 h led to significant decrease on proliferation index, mitotic index, and nuclear division index (NDI). Also, all decreases were concentration-dependent (except NDI at 24 h treatment period). Consequently, the findings of this research showed that flurbiprofen had cytotoxic effects in human blood lymphocytes.

Modulatory effects of garlic extract against the cyclophosphamide induced genotoxicity in human lymphocytes in vitro.

PubMed

Sowjanya, B Lakshmi; Devi, K Rudrama; Madhavi, D

2009-09-01

Cyclophosphamide (CP) is a commonly used chemotherapeutic and immunosuppressive agent which is used in the treatment of wide range of cancers and autoimmune diseases. Besides that it is a well known carcinogen. In this study by using chromosomal aberrations (CA) and sister chromatid exchanges (SCE) assays method, the modulatory effects exerted by the extract of garlic against the CP induced genotoxicity in the human lymphocyte cultures in vitro were tested. Three different doses of garlic extract were tested for their modulatory capacity on the mutagenecity exerted by 100 microg ml(-1) of CR The results indicate a significant decrease in the frequency of CA and SCE suggesting that the garlic extract modulates the CP induced genotoxicity in a dose dependent manner. These findings provide the future directions for the research on design and development of possible modulatory drugs containing garlic extract.

Evaluation of toxicity and genotoxicity of 2-chlorophenol on bacteria, fish and human cells.

PubMed

Vlastos, Dimitris; Antonopoulou, Maria; Konstantinou, Ioannis

2016-05-01

Due to the extensive use of chlorophenols (CPs) in anthropogenic activities, 2-Chlorophenol (2-CP), among other CPs, can enter aquatic ecosystems and can be harmful to a variety of organisms, including bacteria, fish and humans, that are exposed directly and/or indirectly to such contaminated environments. Based on the existing knowledge and in order to move a step forward, the purpose of this study is to investigate the toxic and mainly the genotoxic effects of 2-CP using a combination of bioassays. The tests include the marine bacterium Vibrio fischeri and micronuclei induction in the erythrocytes of Carassius auratus as well as in cultured human lymphocytes. The results obtained reveal that 2-CP is able to induce dose-dependent toxic and genotoxic effects on the selected tested concentrations under the specific experimental conditions. Copyright © 2016 Elsevier B.V. All rights reserved.

Evaluation of the sensitivity and specificity of in vivo erythrocyte micronucleus and transgenic rodent gene mutation tests to detect rodent carcinogens.

PubMed

Morita, Takeshi; Hamada, Shuichi; Masumura, Kenichi; Wakata, Akihiro; Maniwa, Jiro; Takasawa, Hironao; Yasunaga, Katsuaki; Hashizume, Tsuneo; Honma, Masamitsu

2016-05-01

Sensitivity and/or specificity of the in vivo erythrocyte micronucleus (MN) and transgenic rodent mutation (TGR) tests to detect rodent carcinogens and non-carcinogens were investigated. The Carcinogenicity and Genotoxicity eXperience (CGX) dataset created by Kirkland et al. was used for the carcinogenicity and in vitro genotoxicity data, i.e., Ames and chromosome aberration (CA) tests. Broad literature surveys were conducted to gather in vivo MN or TGR test data to add to the CGX dataset. Genotoxicity data in vitro were also updated slightly. Data on 379 chemicals (293 carcinogens and 86 non-carcinogens) were available for the in vivo MN test; sensitivity, specificity or concordances were calculated as 41.0%, 60.5% or 45.4%, respectively. For the TGR test, data on 80 chemicals (76 carcinogens and 4 non-carcinogens) were available; sensitivity was calculated as 72.4%. Based on the recent guidance on genotoxicity testing strategies, performance (sensitivity/specificity) of the following combinations was calculated; Ames+in vivo MN (68.7%/45.3%), Ames+TGR (83.8%/not calculated (nc)), Ames+in vitro CA+in vivo MN (80.8%/21.3%), Ames+in vitro CA+TGR (89.1%/nc), Ames+in vivo MN+TGR (87.5%/nc), Ames+in vitro CA+in vivo MN+TGR (89.3%/nc). Relatively good balance in performance was shown by the Ames+in vivo MN in comparison with Ames+in vitro CA (74.3%/37.5%). Ames+TGR and Ames+in vivo MN+TGR gave even higher sensitivity, but the specificity could not be calculated (too few TGR data on non-carcinogens). This indicates that in vivo MN and TGR tests are both useful as in vivo tests to detect rodent carcinogens. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

A core in vitro genotoxicity battery comprising the Ames test plus the in vitro micronucleus test is sufficient to detect rodent carcinogens and in vivo genotoxins.

PubMed

Kirkland, David; Reeve, Lesley; Gatehouse, David; Vanparys, Philippe

2011-03-18

In vitro genotoxicity testing needs to include tests in both bacterial and mammalian cells, and be able to detect gene mutations, chromosomal damage and aneuploidy. This may be achieved by a combination of the Ames test (detects gene mutations) and the in vitro micronucleus test (MNvit), since the latter detects both chromosomal aberrations and aneuploidy. In this paper we therefore present an analysis of an existing database of rodent carcinogens and a new database of in vivo genotoxins in terms of the in vitro genotoxicity tests needed to detect their in vivo activity. Published in vitro data from at least one test system (most were from the Ames test) were available for 557 carcinogens and 405 in vivo genotoxins. Because there are fewer publications on the MNvit than for other mammalian cell tests, and because the concordance between the MNvit and the in vitro chromosomal aberration (CAvit) test is so high for clastogenic activity, positive results in the CAvit test were taken as indicative of a positive result in the MNvit where there were no, or only inadequate data for the latter. Also, because Hprt and Tk loci both detect gene-mutation activity, a positive Hprt test was taken as indicative of a mouse-lymphoma Tk assay (MLA)-positive, where there were no data for the latter. Almost all of the 962 rodent carcinogens and in vivo genotoxins were detected by an in vitro battery comprising Ames+MNvit. An additional 11 carcinogens and six in vivo genotoxins would apparently be detected by the MLA, but many of these had not been tested in the MNvit or CAvit tests. Only four chemicals emerge as potentially being more readily detected in MLA than in Ames+MNvit--benzyl acetate, toluene, morphine and thiabendazole--and none of these are convincing cases to argue for the inclusion of the MLA in addition to Ames+MNvit. Thus, there is no convincing evidence that any genotoxic rodent carcinogens or in vivo genotoxins would remain undetected in an in vitro test battery consisting of Ames+MNvit. Copyright © 2011 Elsevier B.V. All rights reserved.

Genotoxicity assessment of multispecies probiotics using reverse mutation, mammalian chromosomal aberration, and rodent micronucleus tests.

PubMed

Chiu, Yi-Jen; Nam, Mun-Kit; Tsai, Yueh-Ting; Huang, Chun-Chi; Tsai, Cheng-Chih

2013-01-01

Genotoxicity assessment is carried out on freeze dried powder of cultured probiotics containing Lactobacillus rhamnosus LCR177, Bifidobacterium adolescentis BA286, and Pediococcus acidilactici PA318. Ames tests, in vitro mammalian chromosome aberration assay, and micronucleus tests in mouse peripheral blood are performed. For 5 strains of Salmonella Typhimurium, the Ames tests show no increased reverse mutation upon exposure to the test substance. In CHO cells, the frequency of chromosome aberration does not increase in responding to the treatment of probiotics. Likewise, the frequency of micronucleated reticulocytes in probiotics-fed mice is indistinguishable from that in the negative control group. Taken together, the toxicity assessment studies suggest that the multispecies probiotic mixture does not have mutagenic effects on various organisms.

Results of the International Validation of the in vivo rodent alkaline comet assay for the detection of genotoxic carcinogens: Individual data for 1,2-dibromoethane, p-anisidine, and o-anthranilic acid in the 2nd step of the 4th phase Validation Study under the JaCVAM initiative.

PubMed

Takasawa, Hironao; Takashima, Rie; Narumi, Kazunori; Kawasako, Kazufumi; Hattori, Akiko; Kawabata, Masayoshi; Hamada, Shuichi

2015-07-01

As part of the Japanese Center for the Validation of Alternative Methods (JaCVAM)-initiative International Validation Study of an in vivo rat alkaline comet assay, we examined 1,2-dibromoethane (DBE), p-anisidine (ASD), and o-anthranilic acid (ANT) to investigate the effectiveness of the comet assay in detecting genotoxic carcinogens. Each of the three test chemicals was administered to 5 male Sprague-Dawley rats per group by oral gavage at 48, 24, and 3h before specimen preparation. Single cells were collected from the liver and glandular stomach at 3h after the final dosing, and the specimens prepared from these two organs were subjected to electrophoresis under alkaline conditions (pH>13). The percentage of DNA intensity in the comet tail was then assessed using an image analysis system. A micronucleus (MN) assay was also conducted using these three test chemicals with the bone marrow (BM) cells collected from the same animals simultaneously used in the comet assay, i.e., combination study of the comet assay and BM MN assay. A genotoxic (Ames positive) rodent carcinogen, DBE gave a positive result in the comet assay in the present study, while a genotoxic (Ames positive) non-carcinogen, ASD and a non-genotoxic (Ames negative) non-carcinogen, ANT showed negative results in the comet assay. All three chemicals produced negative results in the BM MN assay. While the comet assay findings in the present study were consistent with those obtained from the rodent carcinogenicity studies for the three test chemicals, we consider the positive result in the comet assay for DBE to be particularly meaningful, given that this chemical produced a negative result in the BM MN assay. Therefore, the combination study of the comet assay and BM MN assay is a useful method to detect genotoxic carcinogens that are undetectable with the BM MN assay alone. Copyright © 2015 Elsevier B.V. All rights reserved.

Efficacy of two wastewater treatment plants in removing genotoxins.

PubMed

Jolibois, B; Guerbet, M

2005-04-01

The genotoxic potential of influents and effluents of two different wastewater treatment plants (WTP-A and WTP-B) located in the Rouen, France, area was evaluated by the SOS chromotest without metabolic activation (on Escherichia coli PQ37) and the Ames fluctuation test (on Salmonella typhimurium strains TA 98, 100, TA 102) with and without metabolic activation. The wastewater samples were taken during two 1-week periods in January and April 2003. The simultaneous use of the SOS chromotest and Ames fluctuation test allowed us to evaluate the efficacy of the wastewater treatment plants at removing genotoxins. Genotoxins were detected with the Ames test but not with the SOS chromotest. Out of a total of 24 influents tested (14 for WTP-A and 10 for WTP-B), almost all were genotoxic in at least one Ames test strain (71% for WTP-A and 100% for WTP-B). In contrast, all of the tested effluents were nongenotoxic. This work showed that the treatment process used in the 2 wastewater treatment plants studied (activated sludge) was able to remove the genotoxins detected in their influents. Nevertheless, studies could be undertaken to determine which step of the treatment process removes genotoxins and whether WTP sludge use could be a source of genotoxic contamination for humans and the environment.

Chemopreventive effect and lack of genotoxicity and mutagenicity of the exopolysaccharide botryosphaeran on human lymphocytes.

PubMed

Malini, M; Camargo, M S; Hernandes, L C; Vargas-Rechia, C G; Varanda, E A; Barbosa, A M; Dekker, R F H; Matsumoto, S T; Antunes, L M G; Cólus, I M S

2016-10-01

Carbohydrate biopolymers of fungal-origin are an important natural resource in the search for new bioagents with therapeutic and nutraceutical potential. In this study the mutagenic, genotoxic, antigenotoxic and antioxidant properties of the fungal exopolysaccharide botryosphaeran, a (1→3)(1→6)-β-D-glucan, from Botryosphaeria rhodina MAMB-05, was evaluated. The mutagenicity was assessed at five concentrations in Salmonella typhimurium by the Ames test. Normal and tumor (Jurkat cells) human T lymphocyte cultures were used to evaluate the genotoxicity and antigenotoxicity (Comet assay) of botryosphaeran alone and in combination with the mutagen methyl methanesulfonate (MMS). The ability of botryosphaeran to reduce the production of reactive oxygen and nitrogen species (RONS) generated by hydrogen peroxide was assessed using the CM-H2DCFDA probe in lymphocyte cultures under different treatment times. None of the evaluated botryosphaeran concentrations were mutagenic in bacteria, nor induced genotoxicity in normal and tumor lymphocytes. Botryosphaeran protected lymphocyte DNA against damage caused by MMS under simultaneous treatment and post-treatment conditions. However, botryosphaeran was not able to reduce the RONS generated by H2O2. Besides the absence of genotoxicity, botryosphaeran exerted a protective effect on human lymphocytes against genotoxic damage caused by MMS. These results are important in the validation of botryosphaeran as a therapeutic agent targeting health promotion. Copyright © 2016 Elsevier Ltd. All rights reserved.

Behavioral and genotoxic evaluation of rosmarinic and caffeic acid in acute seizure models induced by pentylenetetrazole and pilocarpine in mice.

PubMed

Coelho, Vanessa Rodrigues; Vieira, Caroline Gonçalves; de Souza, Luana Pereira; da Silva, Lucas Lima; Pflüger, Pricila; Regner, Gabriela Gregory; Papke, Débora Kuck Mausolff; Picada, Jaqueline Nascimento; Pereira, Patrícia

2016-11-01

The goal of this study was to investigate the effects of rosmarinic acid (RA) and caffeic acid (CA) in the acute pentylenetetrazole (PTZ) and pilocarpine (PIL) seizure models. We also evaluated the effect of RA and CA on the diazepam (DZP)-induced sleeping time test and its possible neuroprotective effect against the genotoxic damage induced by PTZ and PIL. Mice were treated intraperitoneally (i.p.) with saline, RA (2 or 4 mg/kg), or CA (4 or 8 mg/kg) alone or associated to low-dose DZP. After, mice received a single dose of PTZ (88 mg/kg) or PIL (250 mg/kg) and were monitored for the percentage of seizures and the latency to first seizure (LFS) >3 s. Vigabatrin and DZP were used as positive controls. In the DZP-induced sleeping time test, mice were treated with RA and CA and 30 min after receiving DZP (25 mg/kg, i.p.). The alkaline comet assay was performed after acute seizure tests to evaluate the antigenotoxic profiles of RA and CA. The doses of RA and CA tested alone did not reduce the occurrence of seizures induced by PTZ or PIL. The association of 4 mg/kg RA + low-dose DZP was shown to increase LFS in the PTZ model, compared to the group that received only the DZP. In the DZP-induced sleeping time test, the latency to sleep was reduced by 4 mg/kg RA and 8 mg/kg CA. The PTZ-induced genotoxic damage was not prevented by RA or CA, but the PIL-induced genotoxic damage was decreased by pretreatment with 4 mg/kg RA (in cortex) and 4 mg/kg CA (in hippocampus). In conclusion, RA and CA presented neuroprotective effect against PIL-induced genotoxic damage and reduced the latency to DZP-induced sleep. Of the rosmarinic acid, 4 mg/kg enhanced the DZP effect in the increase of latency to clonic PTZ-induced seizures.

Studies on the genotoxic properties of essential oils with Bacillus subtilis rec-assay and Salmonella/microsome reversion assay.

PubMed

Zani, F; Massimo, G; Benvenuti, S; Bianchi, A; Albasini, A; Melegari, M; Vampa, G; Bellotti, A; Mazza, P

1991-06-01

Genotoxic properties of essential oils from Anthemis nobilis L., Artemisia dracunculus L., Salvia officinalis L., Salvia sclarea L., Satureja hortensis L., Satureja montana L., Thymus capitatus L., Thymus citriodorus Schreb., Thymus vulgaris L., Citrus bergamia Risso, were studied with Bacillus subtilis rec-assay and Salmonella/microsome reversion assay. The essential oil of Artemisia dracunculus L. "Piemontese" turned out to be active in the rec-assay but not in the Salmonella test. DNA-damaging activity was demonstrated to be due to the estragol component of the oil. Advantages of the combined use of these two short-term microbial assays in genotoxic studies are discussed.

Application of the SOS/umu test and high-content in vitro micronucleus test to determine genotoxicity and cytotoxicity of nine benzothiazoles.

PubMed

Ye, Yan; Weiwei, Jiang; Na, Li; Mei, Ma; Kaifeng, Rao; Zijian, Wang

2014-12-01

Benzothiazole and benzothiazole derivatives (BTs) have been detected in various environmental matrices as well as in human beings, but little is currently available regarding their toxicities. In our study, genotoxicities of nine BTs (benzothiazole [BT], 2-chlorobenzothiazole [CBT], 2-bromobenzothiazole [BrBT], 2-fluorobenzothiazole [FBT], 2-methylbenzothiazole [MeBT], 2-mercaptobenzothiazole [MBT], 2-aminobenzothiazole [ABT], 2-hydroxy-benzothiazole [OHBT] and 2-methythiobenzothiazole [MTBT]) are comprehensively evaluated by the SOS/umu test using the bacterial Salmonella typhimurium TA1535/pSK1002 for DNA-damaging effect and the high content in vitro micronucleus test using two human carcinoma cells (MGC-803 and A549) for chromosome-damaging effect. The cytotoxicity of BTs on both bacteria and two human cells was also evaluated. Except for the cytotoxic effect of MBT on MGC-803 and A549, the other tested BTs showed more than 50% cytotoxicity at their highest concentrations in a dose-dependent manner, and their LC50s ranged from 19 (MBT in bacteria) to 270 mg l(-1) (CBT in A549). Activation and inactivation were observed for specific BTs after metabolism. On the other hand, no evidence of genotoxicity was obtained for BT, FBT and MBT, and DNA damage was induced by ABT, OHBT, BrBT and MTBT in MGC-803, by MeBT in A549 and by CBT in both cells. Through quantitative structure-activity relationship analysis, two structure alerts for chemical genotoxicity, including heterocyclic amine and hacceptor-path3-hacceptor are present in ABT and OHBT respectively; however, the underlying mechanisms still need further evaluation. Copyright © 2014 John Wiley & Sons, Ltd.

Study of serum interaction with a cationic nanoparticle: Implications for in vitro endocytosis, cytotoxicity and genotoxicity.

PubMed

Merhi, Maysaloun; Dombu, Christophe Youta; Brient, Alizée; Chang, Jiang; Platel, Anne; Le Curieux, Frank; Marzin, Daniel; Nesslany, Fabrice; Betbeder, Didier

2012-02-14

We used well-characterized and positively charged nanoparticles (NP(+)) to investigate the importance of cell culture conditions, specifically the presence of serum and proteins, on NP(+) physicochemical characteristics, and the consequences for their endocytosis and genotoxicity in bronchial epithelial cells (16HBE14o-). NP(+) surface charge was significantly reduced, proportionally to NP(+)/serum and NP(+)/BSA ratios, while NP(+) size was not modified. Microscopy studies showed high endocytosis of NP(+) in 16HBE14o-, and serum/proteins impaired this internalization in a dose-dependent manner. Toxicity studies showed no cytotoxicity, even for very high doses of NP(+). No genotoxicity was observed with classic comet assay while primary oxidative DNA damage was observed when using the lesion-specific repair enzyme, formamidopyrimidine DNA-glycosylase (FPG). The micronucleus test showed NP(+) genotoxicity only for very high doses that cannot be attained in vivo. The low toxicity of these NP(+) might be explained by their high exocytosis from 16HBE14o- cells. Our results confirm the importance of serum and proteins on nanoparticles endocytosis and genotoxicity. Copyright © 2011 Elsevier B.V. All rights reserved.

Contributions of flumequine and nitroarenes to the genotoxicity of river and ground waters.

PubMed

Ma, Fujun; Yuan, Guanxiang; Meng, Liping; Oda, Yoshimitsu; Hu, Jianying

2012-07-01

The SOS/umuC assay was performed in conjunction with analytical measurements to identify potential genotoxins in river and adjacent ground waters in the Jialu River basin, China. The major genotoxic activities of the river and adjacent ground waters occurred in the same two fractions (F4 and F11) when assayed using the Salmonella typhimurium strain TA1535/pSK1002. This indicates that ground water near the Jialu River was influenced by the river water. LC-MS/MS analysis indicated that flumequine accounted for 86% and 76% of the genotoxicity in fraction F11 of the river and adjacent ground waters, respectively. When HPLC fractions were tested using the strain NM3009, three fractions showed genotoxic activities for river water sample, while no fractions from ground water samples elicited genotoxic activities. The specific response to the strain NM3009 in one fraction compared with the strain TA1535/pSK1002 suggested the presence of nitroarenes. However, we failed to identify the exact nitroarenes when GC-MS analysis was used to analyze nitroarenes which are well detected in air and soil samples in previous papers. Copyright © 2012 Elsevier Ltd. All rights reserved.

Lack of genotoxicity in medical oncology nurses handling antineoplastic drugs: effect of work environment and protective equipment.

PubMed

Gulten, Tuna; Evke, Elif; Ercan, Ilker; Evrensel, Turkkan; Kurt, Ender; Manavoglu, Osman

2011-01-01

In this study we aimed to investigate the genotoxic effects of antineoplastic agents in occupationally exposed oncology nurses. Genotoxic effects mean the disruptive effects in the integrity of DNA and they are associated with cancer development. Biomonitoring of health care workers handling antineoplastic agents is helpful for the evaluation of exposure to cytostatics. The study included an exposed and two control groups. The exposed group (n=9) was comprised of oncology nurses. The first (n=9) and second (n=10) control groups were comprised of subjects who did not come into contact with antineoplastic drugs working respectively in the same department with oncology nurses and in different departments. Genotoxicity evaluation was performed using SCE analysis. After applying culture, harvest and chromosome staining procedures, a total of 25 metaphases were analyzed per person. Kruskal Wallis test was used to perform statistical analysis. A statistically significant difference of sister chromatid exchange frequencies was not observed between the exposed and control groups. Lack of genotoxicity in medical oncology nurses might be due to good working conditions with high standards of technical equipment and improved personal protection.

Genotoxicity of corrosion eluates obtained from endosseous implants.

PubMed

Ribeiro, Daniel Araki; Matsumoto, Mariza Akemi; Padovan, Luís Eduardo Marques; Marques, Mariângela Esther Alencar; Salvadori, Daisy Maria Fávero

2007-03-01

Commercially pure titanium alloys are currently used as metallic biomaterials in implantology. Corrosion phenomena appear to play a decisive role in metallic implant long-term behavior. Thus, the goal of this study was to examine the genotoxic potential of corrosion eluates obtained from dental implants using Chinese ovary hamster cells in vitro by the single-cell gel (comet) assay. This technique detects deoxyribonucleic acid strand breaks in individual cells in alkaline conditions. The materials tested included 3 dental implants commercially available. Each of the tested materials was corroded in a solution consisting of equal amounts of acetic acid and sodium chloride (0.1 M) for 1, 3, 7, 14, and 21 days. The Chinese ovary hamster cultures were then exposed to all corrosion eluates obtained from endosseous dental implants for 30 minutes at 37 degrees C. None of the eluates was found to exhibit genotoxicity, regardless of the type of dental implant used. The results suggest that all dental implants tested in this study did not induce deoxyribonucleic acid breakage as depicted by the single-cell gel (comet) assay.

Biocompatibility of hyaluronic acid hydrogels prepared by porous hyaluronic acid microbeads

NASA Astrophysics Data System (ADS)

Kim, Jin-Tae; Lee, Deuk Yong; Kim, Tae-Hyung; Song, Yo-Seung; Cho, Nam-Ihn

2014-05-01

Hyaluronic acid hydrogels (HAHs) were synthesized by immersing HA microbeads crosslinked with divinyl sulfone in a phosphate buffered saline solution to evaluate the biocompatibility of the gels by means of cytotoxicity, genotoxicity ( in vitro chromosome aberration test, reverse mutation assay, and in vivo micronucleus test), skin sensitization, and intradermal reactivity. The HAHs induced no cytotoxicity or genotoxicity. In guinea pigs treated with grafts and prostheses, no animals died and there were no abnormal clinical signs. The sensitization scores were zero in all guinea pigs after 24 h and 48 h challenge, suggesting that the HAHs had no contact allergic sensitization in the guinea pig maximization test. No abnormal signs were found in New Zealand White rabbits during the 72 h observation period after the injection. There was no difference between the HAHs and negative control mean scores because skin reaction such as erythema or oedema was not observed after injection. Experimental results suggest that the HAHs would be suitable for soft tissue augmentation due to the absence of cytotoxicity, genotoxicity, skin sensitization, and intradermal reactivity.

A review of the genotoxicity of trimethylolpropane triacrylate (TMPTA).

PubMed

Kirkland, David; Fowler, Paul

2018-04-01

Trimethylolpropane triacrylate (TMPTA) is a trifunctional acrylate monomer which polymerizes rapidly when exposed to sources of free radicals. It is widely used as a reactive diluent and polymer building block in the formulation of overprint varnishes, inks and a variety of wood, plastic and metal coatings. TMPTA has been tested in a range of in vitro and in vivo genotoxicity tests. There is no clear evidence of induction of gene mutations by TMPTA in bacteria or mammalian cells in vitro, but there is evidence of clastogenicity from induction of small colony tk mutants in the mouse lymphoma assay, and also induction of micronuclei and chromosomal aberrations. However, TMPTA was negative in bone marrow or blood micronucleus tests in vivo following oral or repeated dermal application, and did not induce comets in bone marrow or liver of mice following intravenous administration, which would have achieved plasma (and therefore tissue) concentrations estimated to exceed those inducing clastogenic effects in vitro. It is concluded that TMPTA is not genotoxic in vivo. Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.

Diversity Outbred Mice Identify Population-Based Exposure Thresholds and Genetic Factors that Influence Benzene-Induced Genotoxicity

PubMed Central

Gatti, Daniel M.; Morgan, Daniel L.; Kissling, Grace E.; Shockley, Keith R.; Knudsen, Gabriel A.; Shepard, Kim G.; Price, Herman C.; King, Deborah; Witt, Kristine L.; Pedersen, Lars C.; Munger, Steven C.; Svenson, Karen L.; Churchill, Gary A.

2014-01-01

Background Inhalation of benzene at levels below the current exposure limit values leads to hematotoxicity in occupationally exposed workers. Objective We sought to evaluate Diversity Outbred (DO) mice as a tool for exposure threshold assessment and to identify genetic factors that influence benzene-induced genotoxicity. Methods We exposed male DO mice to benzene (0, 1, 10, or 100 ppm; 75 mice/exposure group) via inhalation for 28 days (6 hr/day for 5 days/week). The study was repeated using two independent cohorts of 300 animals each. We measured micronuclei frequency in reticulocytes from peripheral blood and bone marrow and applied benchmark concentration modeling to estimate exposure thresholds. We genotyped the mice and performed linkage analysis. Results We observed a dose-dependent increase in benzene-induced chromosomal damage and estimated a benchmark concentration limit of 0.205 ppm benzene using DO mice. This estimate is an order of magnitude below the value estimated using B6C3F1 mice. We identified a locus on Chr 10 (31.87 Mb) that contained a pair of overexpressed sulfotransferases that were inversely correlated with genotoxicity. Conclusions The genetically diverse DO mice provided a reproducible response to benzene exposure. The DO mice display interindividual variation in toxicity response and, as such, may more accurately reflect the range of response that is observed in human populations. Studies using DO mice can localize genetic associations with high precision. The identification of sulfotransferases as candidate genes suggests that DO mice may provide additional insight into benzene-induced genotoxicity. Citation French JE, Gatti DM, Morgan DL, Kissling GE, Shockley KR, Knudsen GA, Shepard KG, Price HC, King D, Witt KL, Pedersen LC, Munger SC, Svenson KL, Churchill GA. 2015. Diversity Outbred mice identify population-based exposure thresholds and genetic factors that influence benzene-induced genotoxicity. Environ Health Perspect 123:237–245; http://dx.doi.org/10.1289/ehp.1408202 PMID:25376053

Investigation on the toxic potential of Tribulus terrestris in vitro.

PubMed

Abudayyak, M; Jannuzzi, A T; Özhan, G; Alpertunga, B

2015-04-01

Tribulus terrestris L. (Zygophyllaceae) has been commonly used to energize, vitalize, and improve sexual function and physical performance in men. This study investigates the potential cytotoxic and genotoxic, and endocrine disrupting activities of T. terrestris in vitro. The whole T. terrestris plant was extracted with water, methanol, and chloroform. The genotoxic potential of T. terrestris extracts at 3-2400 µg/mL was assessed by Comet assay in a rat kidney cell line (NRK-52E) and by Ames assay in Salmonella typhimurium TA98 and TA100 strains. Endocrine disrupting effects of the extracts at concentrations of 0.22-25 000 µg/mL were assessed by YES/YAS assay in Saccharomyces cerevisiae. Cytotoxic activity of the extracts was determined by the MTT test in NRK-52E cells. The different exposure times were used for four tests (3-48 h). The methanol extract of T. terrestris IC50 value was 160 µg/mL. The other extracts did not show cytotoxic effects. In the Comet and Ames genotoxicity assays, none of the extracts possessed genotoxic activities at concentrations of 0-2400 µg/mL. Only the water extract of T. terrestris induced frame shift mutations after metabolic activation. The water extract also showed estrogenic activity by YES/YAS assay in S. cerevisiae at concentrations ≥27 µg/mL (≥2.6-fold), while the other T. terrestris extracts had anti-estrogenic properties. Tribulus terrestris had estrogenic and genotoxic activities. The study was useful in determining its toxicological effects and the precautions regarding consumption.

Genotoxic potential of diesel exhaust particles from the combustion of first- and second-generation biodiesel fuels-the FuelHealth project.

PubMed

Kowalska, Magdalena; Wegierek-Ciuk, Aneta; Brzoska, Kamil; Wojewodzka, Maria; Meczynska-Wielgosz, Sylwia; Gromadzka-Ostrowska, Joanna; Mruk, Remigiusz; Øvrevik, Johan; Kruszewski, Marcin; Lankoff, Anna

2017-11-01

Epidemiological data indicate that exposure to diesel exhaust particles (DEPs) from traffic emissions is associated with higher risk of morbidity and mortality related to cardiovascular and pulmonary diseases, accelerated progression of atherosclerotic plaques, and possible lung cancer. While the impact of DEPs from combustion of fossil diesel fuel on human health has been extensively studied, current knowledge of DEPs from combustion of biofuels provides limited and inconsistent information about its mutagenicity and genotoxicity, as well as possible adverse health risks. The objective of the present work was to compare the genotoxicity of DEPs from combustion of two first-generation fuels, 7% fatty acid methyl esters (FAME) (B7) and 20% FAME (B20), and a second-generation 20% FAME/hydrotreated vegetable oil (SHB: synthetic hydrocarbon biofuel) fuel. Our results revealed that particulate engine emissions from each type of biodiesel fuel induced genotoxic effects in BEAS-2B and A549 cells, manifested as the increased levels of single-strand breaks, the increased frequencies of micronuclei, or the deregulated expression of genes involved in DNA damage signaling pathways. We also found that none of the tested DEPs showed the induction of oxidative DNA damage and the gamma-H2AX-detectable double-strand breaks. The most pronounced differences concerning the tested particles were observed for the induction of single-strand breaks, with the greatest genotoxicity being associated with the B7-derived DEPs. The differences in other effects between DEPs from the different biodiesel blend percentage and biodiesel feedstock were also observed, but the magnitude of these variations was limited.

Genotoxicity and growth inhibition effects of aniline on wheat.

PubMed

Tao, Nan; Liu, Guanyi; Bai, Lu; Tang, Lu; Guo, Changhong

2017-02-01

Aniline is a synthetic compound widely used in industrial and pesticide production, which can lead to environmental pollution. Its high concentration in rivers and lakes is hazardous to aquatic species. Although the mechanism of aniline toxicity has been studied extensively in animals and algae, little is known about its genotoxicity in plants. In this study, we investigated the genotoxicity effects of aniline on wheat root tip cells. The mitotic index of wheat root tip cells decreased when the aniline test concentration was higher than 10 mg L -1 . The frequency of micronucleus and chromosomal aberrations increased at aniline concentrations ranging between 5 and 100 mg L -1 , and reached 23.3‰ ± 0.3‰ and 8.9‰ ± 0.68‰, respectively, at an aniline concentration of 100 mg L -1 . These values were sevenfold higher than those in the control group. The wheat seedlings showed various growth toxicity effects under different concentrations of aniline. The shoot height, root length, fresh weight, and dry weight of wheat seedlings decreased at aniline test concentrations ranging between 25 and 200 mg L -1 . At 200 mg L -1 aniline, the dry weight was only one-third that of the control group. Overall, the findings of this study provide evidence that aniline is a serious environmental pollutant causing deleterious genotoxic effects on wheat root tip cells and growth toxic effects on wheat seedlings. However, understanding the mechanisms that underlie aniline genotoxicity in plants needs further study. Copyright © 2016 Elsevier Ltd. All rights reserved.

The combination of two novel tobacco blends and filter technologies to reduce the in vitro genotoxicity and cytotoxicity of prototype cigarettes.

PubMed

Crooks, Ian; Scott, Ken; Dalrymple, Annette; Dillon, Debbie; Meredith, Clive

2015-04-01

Tobacco smoke from a combustible cigarette contains more than 6000 constituents; approximately 150 of these are identified as toxicants. Technologies that modify the tobacco blend to reduce toxicant emissions have been developed. These include tobacco sheet substitute to dilute toxicants in smoke and blend treated tobacco to reduce the levels of nitrogenous precursors and some polyphenols. Filter additives to reduce gas (vapour) phase constituents have also been developed. In this study, both tobacco blend and filter technologies were combined into an experimental cigarette and smoked to International Organisation on Standardisation and Health Canada puffing parameters. The resulting particulate matter was subjected to a battery of in vitro genotoxicity and cytotoxicity assays - the Ames test, mouse lymphoma assay, the in vitro micronucleus test and the Neutral Red Uptake assay. The results indicate that cigarettes containing toxicant reducing technologies may be developed without observing new additional genotoxic hazards as assessed by the assays specified. In addition, reductions in bacterial mutagenicity and mammalian genotoxicity of the experimental cigarette were observed relative to the control cigarettes. There were no significant differences in cytotoxicity relative to the control cigarettes. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

Genotoxic activities of the food contaminant 5-hydroxymethylfurfural using different in vitro bioassays.

PubMed

Severin, Isabelle; Dumont, Coralie; Jondeau-Cabaton, Adeline; Graillot, Vanessa; Chagnon, Marie-Christine

2010-02-01

5-Hydroxymethylfurfural (5-HMF) is known as an indicator of quality deterioration in a wide range of foods. 5-HMF is formed as an intermediate in the Maillard reaction and has been identified in a wide variety of heat-processed foods. In recent years, the presence of 5-HMF in foods has raised toxicological concerns: data have shown cytotoxic, genotoxic and tumoral effects but further studies suggest that 5-HMF does not pose a serious health risk. However the subject is still a matter of debate. We investigated the genotoxicity of the food-borne contaminant 5-HMF using the Ames test, the micronucleus (MN) and the single-cell gel electrophoresis (SCGE) assays in the human metabolically active HepG2 cell line. Cytotoxic effect of 5-HMF was first assessed using Alamar Blue as a sensitive sub-lethal assay. 5-HMF did not induce any genic mutation in bacteria whatever the concentration in the Ames test. Furthermore, it does not induce clastogenic or aneugenic effects in the HepG2 cells. In contrast, 5-HMF induced HepG2 DNA damage at concentrations from 7.87 to 25 mM in the comet assay suggesting a weak genotoxic effect of 5-HMF in the HepG2 cells probably repaired. 2009 Elsevier Ireland Ltd. All rights reserved.

Dry olive leaf extract counteracts L-thyroxine-induced genotoxicity in human peripheral blood leukocytes in vitro.

PubMed

Topalović, Dijana Žukovec; Živković, Lada; Čabarkapa, Andrea; Djelić, Ninoslav; Bajić, Vladan; Dekanski, Dragana; Spremo-Potparević, Biljana

2015-01-01

The thyroid hormones change the rate of basal metabolism, modulating the consumption of oxygen and causing production of reactive oxygen species, which leads to the development of oxidative stress and DNA strand breaks. Olive (Olea europaea L.) leaf contains many potentially bioactive compounds, making it one of the most potent natural antioxidants. The objective of this study was to evaluate the genotoxicity of L-thyroxine and to investigate antioxidative and antigenotoxic potential of the standardized oleuropein-rich dry olive leaf extract (DOLE) against hydrogen peroxide and L-thyroxine-induced DNA damage in human peripheral blood leukocytes by using the comet assay. Various concentrations of the extract were tested with both DNA damage inducers, under two different experimental conditions, pretreatment and posttreatment. Results indicate that L-thyroxine exhibited genotoxic effect and that DOLE displayed protective effect against thyroxine-induced genotoxicity. The number of cells with DNA damage, was significantly reduced, in both pretreated and posttreated samples (P < 0.05). Comparing the beneficial effect of all tested concentrations of DOLE, in both experimental protocols, it appears that extract was more effective in reducing DNA damage in the pretreatment, exhibiting protective role against L-thyroxine effect. This feature of DOLE can be explained by its capacity to act as potent free radical scavenger.

Carboxylated nanodiamonds can be used as negative reference in in vitro nanogenotoxicity studies.

PubMed

Moche, H; Paget, V; Chevalier, D; Lorge, E; Claude, N; Girard, H A; Arnault, J C; Chevillard, S; Nesslany, F

2017-08-01

Nanodiamonds (NDs) are promising nanomaterials for biomedical applications. However, a few studies highlighted an in vitro genotoxic activity for detonation NDs, which was not evidenced in one of our previous work quantifying γ-H2Ax after 20 and 100 nm high-pressure high-temperature ND exposures of several cell lines. To confirm these results, in the present work, we investigated the genotoxicity of the same 20 and 100 nm NDs and added intermediate-sized NDs of 50 nm. Conventional in vitro genotoxicity tests were used, i.e., the in vitro micronucleus and comet assays that are recommended by the French National Agency for Medicines and Health Products Safety for the toxicological evaluation of nanomedicines. In vitro micronucleus and in vitro comet assays (standard and hOGG1-modified) were therefore performed in two human cell lines, the bronchial epithelial 16HBE14o- cells and the colon carcinoma T84 cells. Our results did not show any genotoxic activity, whatever the test, the cell line or the size of carboxylated NDs. Even though these in vitro results should be confirmed in vivo, they reinforce the potential interest of carboxylated NDs for biomedical applications or even as a negative reference nanoparticle in nanotoxicology. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

Cytotoxicity and genotoxicity evaluation of urban surface waters using freshwater luminescent bacteria Vibrio-qinghaiensis sp.-Q67 and Vicia faba root tip.

PubMed

Ma, Xiaoyan; Wang, Xiaochang; Liu, Yongjun

2012-01-01

The freshwater luminescent bacteria Vibrio-qinghaiensis sp.-Q67 test and the Vicia faba root tip test associated with solid-phase extraction were applied for cytotoxicity and genotoxicity assessment of organic substances in three rivers, two lakes and effluent flows from two wastewater treatment plants (WWTPs) in Xi'an, China. Although the most seriously polluted river with high chemical oxygen demand (COD) and total organic carbon (TOC) showed high cytotoxicity (expressed as TII50, the toxicity impact index) and genotoxicity (expressed as RMCN, the relative frequency of micronucleus), no correlative relation was found between the ecotoxicity and organic content of the water samples. However, there was a linear correlative relation between TII50 and RMCN for most water samples except that from the Zaohe River, which receives discharge from WWTP and untreated industrial wastewaters. The ecotoxicity of the organic toxicants in the Chanhe River and Zaohe River indicated that cytotoxic and genotoxic effects were related to the pollutant source. The TII50 and RMCN were also found to correlate roughly to the dissolved oxygen concentration of the water. Sufficient dissolved oxygen in surface water is thus proved to be an indicator of a healthy water environmental condition.

Bioaccumulation of trace metals and total petroleum and genotoxicity responses in an edible fish population as indicators of marine pollution.

PubMed

D'Costa, Avelyno; Shyama, S K; Praveen Kumar, M K

2017-08-01

The present study reports the genetic damage and the concentrations of trace metals and total petroleum hydrocarbons prevailing in natural populations of an edible fish, Arius arius in different seasons along the coast of Goa, India as an indicator of the pollution status of coastal water. Fish were collected from a suspected polluted site and a reference site in the pre-monsoon, monsoon and post-monsoon seasons. Physico-chemical parameters as well as the concentrations of total petroleum hydrocarbons (TPH) and trace metals in the water and sediment as well as the tissues of fish collected from these sites were recorded. The genotoxicity status of the fish was assessed employing the micronucleus test and comet assay. A positive correlation (p<0.001) was observed between the tail DNA and micronuclei in all the fish collected. Multiple regression analysis revealed that tissue and environmental pollutant concentrations and genotoxicity were positively associated and higher in the tissues of the fish collected from the polluted site. Pollution indicators and genotoxicity tests, combined with other physiological or biochemical parameters represent an essential integrated approach for efficient monitoring of aquatic ecosystems in Goa. Copyright © 2017 Elsevier Inc. All rights reserved.

Genotoxic evaluation of terbinafine in human lymphocytes in vitro.

PubMed

Tolomeotti, Danielle; de Castro-Prado, Marialba Avezum Alves; de Sant'Anna, Juliane Rocha; Martins, Ana Beatriz Tozzo; Della-Rosa, Valter Augusto

2015-01-01

Terbinafine is an antimycotic drug usually used against several superficial fungal infections and with a potential application in the treatment of human cancers. Since to date there are few data on the genotoxic effects of terbinafine in mammalian cells, current study evaluated the potential genotoxic of such antifungal agent in cultured human peripheral blood lymphocytes. Terbinafine was used at the peak plasma concentration (1.0 μg/ml) and in four additional concentrations higher than the human plasmatic peak (5.0 μg/ml, 25.0 μg/ml, 50.0 μg/ml and 100.0 μg/ml). Chromosomal aberrations (CA), sister chromatid exchanges (SCE), micronuclei (MN), nucleoplasmic bridges (NP) and nuclear buds (NB) were scored as genetic endpoints. In all analysis no significant differences (α = 0.05, Kruskal-Wallis test) were observed. Complementary criterion adopted to obtain the final response in cytogenetic agreed with statistical results. Therefore, results of this study showed that terbinafine neither induced CA, SCE, MN, NP and NB nor affected significantly mitotic, replication and cytokinesis-block proliferation indices in any of the tested concentrations. It may be assumed that terbinafine was not genotoxic or cytotoxic to cultured human peripheral blood lymphocytes in our experimental conditions.

Evaluation of the cytotoxicity, genotoxicity, mutagenicity, and antimutagenicity of propolis from Tucuman, Argentina.

PubMed

Nieva Moreno, María I; Zampini, Iris C; Ordóñez, Roxana M; Jaime, Gloria S; Vattuone, Marta A; Isla, María I

2005-11-16

This study evaluates the toxic, genotoxic/mutagenic, and antimutagenic effects of propolis extract from Amaicha del Valle, Tucumán, Argentina. The cytotoxicity assays carried out with the lethality test of Artemia salina revealed that the LD50 was around 100 microg/mL. Propolis extracts showed no toxicity to Salmonella typhimurium TA98 and TA100 strains and Allium cepa at concentrations that have antibiotic and antioxidant activities. Otherwise, for the testing doses, neither genotoxicity nor mutagenicity was found in any sample. The propolis extracts were able to inhibit the mutagenesis of isoquinoline (IQ) and 4-nitro o-phenylenediamine (NPD) with ID50 values of 40 and 20 microg/plate, respectively. From this result, the studied propolis may be inferred to contain some chemical compounds capable of inhibiting the mutagenicity of direct-acting and indirect-acting mutagens. A compound isolated from Amaicha del Valle propolis, 2',4'-dihydroxychalcone, showed cytotoxic activity (LC50 values of 0.5 microg/mL) but was not genotoxic or mutagenic. Furthermore, this compound was able to inhibit the mutagenicity of IQ (ID50 values of 1 microg/plate) but was unable to inhibit the mutagenicity of NPD. Our results suggest a potential anticarcinogenic activity of Amaicha del Valle propolis and the chalcone isolated from it.

Integration of genotoxicity and population genetic analyses in kangaroo rats (Dipodomys merriami) exposed to radionuclide contamination at the Nevada Test Site, USA

USGS Publications Warehouse

Theodorakis, Christopher W.; Bickham, John W.; Lamb, Trip; Medica, Philip A.; Lyne, T. Barrett

2001-01-01

We examined effects of radionuclide exposure at two atomic blast sites on kangaroo rats (Dipodomys merriami) at the Nevada Test Site, Nevada, USA, using genotoxicity and population genetic analyses. We assessed chromosome damage by micronucleus and flow cytometric assays and genetic variation by randomly amplified polymorphic DNA (RAPD) and mitochondrial DNA (mtDNA) analyses. The RAPD analysis showed no population structure, but mtDNA exhibited differentiation among and within populations. Genotoxicity effects were not observed when all individuals were analyzed. However, individuals with mtDNA haplotypes unique to the contaminated sites had greater chromosomal damage than contaminated-site individuals with haplotypes shared with reference sites. When interpopulation comparisons used individuals with unique haplotypes, one contaminated site had greater levels of chromosome damage than one or both of the reference sites. We hypothesize that shared-haplotype individuals are potential migrants and that unique-haplotype individuals are potential long-term residents. A parsimony approach was used to estimate the minimum number of migration events necessary to explain the haplotype distributions on a phylogenetic tree. The observed predominance of migration events into the contaminated sites supported our migration hypothesis. We conclude the atomic blast sites are ecological sinks and that immigration masks the genotoxic effects of radiation on the resident populations.

Cytotoxic and genotoxic potential of geraniol in peripheral blood mononuclear cells and human hepatoma cell line (HepG2).

PubMed

Queiroz, T B; Santos, G F; Ventura, S C; Hiruma-Lima, C A; Gaivão, I O M; Maistro, E L

2017-09-27

Geraniol is an acyclic monoterpene alcohol present in the essential oil of many aromatic plants and is one of the most frequently used molecules by the flavor and fragrance industries. The literature also reports its therapeutic potential, highlighting itself especially as a likely molecule for the development of drugs against cancer. In view of these considerations, this study was designed to evaluate the cytotoxic and genotoxic potential of geraniol, in an in vitro protocol, using two types of human cells: one without the ability to metabolize (peripheral blood mononuclear cells - PBMC), and the other with this capability (human hepatoma cell line - HepG2) through the comet assay and the micronucleus test. Four concentrations (10, 25, 50, and 100 µg/mL) were selected for the genotoxic assessment for PBMC and three (1.25, 2.5, and 5 µg/mL) for HepG2 cells based on cytotoxicity tests (MTT assay). Results showed that geraniol did not present genotoxic or clastogenic/aneugenic effects on both cell types under the conditions studied. However, caution is advised in the use of this substance by humans, since a significant reduction in viability of HepG2 and a marked decrease in cell viability on normal PBMC were verified.

Dry Olive Leaf Extract Counteracts L-Thyroxine-Induced Genotoxicity in Human Peripheral Blood Leukocytes In Vitro

PubMed Central

Žukovec Topalović, Dijana; Živković, Lada; Čabarkapa, Andrea; Djelić, Ninoslav; Bajić, Vladan; Spremo-Potparević, Biljana

2015-01-01

The thyroid hormones change the rate of basal metabolism, modulating the consumption of oxygen and causing production of reactive oxygen species, which leads to the development of oxidative stress and DNA strand breaks. Olive (Olea europaea L.) leaf contains many potentially bioactive compounds, making it one of the most potent natural antioxidants. The objective of this study was to evaluate the genotoxicity of L-thyroxine and to investigate antioxidative and antigenotoxic potential of the standardized oleuropein-rich dry olive leaf extract (DOLE) against hydrogen peroxide and L-thyroxine-induced DNA damage in human peripheral blood leukocytes by using the comet assay. Various concentrations of the extract were tested with both DNA damage inducers, under two different experimental conditions, pretreatment and posttreatment. Results indicate that L-thyroxine exhibited genotoxic effect and that DOLE displayed protective effect against thyroxine-induced genotoxicity. The number of cells with DNA damage, was significantly reduced, in both pretreated and posttreated samples (P < 0.05). Comparing the beneficial effect of all tested concentrations of DOLE, in both experimental protocols, it appears that extract was more effective in reducing DNA damage in the pretreatment, exhibiting protective role against L-thyroxine effect. This feature of DOLE can be explained by its capacity to act as potent free radical scavenger. PMID:25789081

Pharmacological inhibition of Polo Like Kinase 2 (PLK2) does not cause chromosomal damage or result in the formation of micronuclei

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fitzgerald, Kent, E-mail: Kent.fitzgerald@elan.com; Bergeron, Marcelle, E-mail: Marcelle.bergeron@elan.com; Willits, Christopher, E-mail: Chris.willits@elan.com

2013-05-15

Polo Like Kinase 2 (PLK2) phosphorylates α-synuclein and is considered a putative therapeutic target for Parkinson's disease. Several lines of evidence indicate that PLK2 is involved with proper centriole duplication and cell cycle regulation, inhibition of which could impact chromosomal integrity during mitosis. The objectives of the series of experiments presented herein were to assess whether specific inhibition of PLK2 is genotoxic and determine if PLK2 could be considered a tractable pharmacological target for Parkinson's disease. Several selective PLK2 inhibitors, ELN 582175 and ELN 582646, and their inactive enantiomers, ELN 582176 and ELN 582647, did not significantly increase the numbermore » of micronuclei in the in vitro micronucleus assay. ELN 582646 was administered to male Sprague Dawley rats in an exploratory 14-day study where flow cytometric analysis of peripheral blood identified a dose-dependent increase in the number of micronucleated reticulocytes. A follow-up investigative study demonstrated that ELN 582646 administered to PLK2 deficient and wildtype mice significantly increased the number of peripheral micronucleated reticulocytes in both genotypes, suggesting that ELN 582646-induced genotoxicity is not through the inhibition of PLK2. Furthermore, significant reduction of retinal phosphorylated α-synuclein levels was observed at three non-genotoxic doses, additional data to suggest that pharmacological inhibition of PLK2 is not the cause of the observed genotoxicity. These data, in aggregate, indicate that PLK2 inhibition is a tractable CNS pharmacological target that does not cause genotoxicity at doses and exposures that engage the target in the sensory retina. - Highlights: • Active and inactive enantiomers test negative in the in vitro micronucleus test. • ELN 582646 significantly increased micronuclei at 100 and 300 mg/kg/day doses. • ELN 582646 significantly increased micronuclei in PLK2 knockout mice. • ELN 582646 decreased phosphorylation of alpha-synuclein at non-genotoxic doses.« less

Application of the micronucleus test and comet assay in Trachemys callirostris erythrocytes as a model for in situ genotoxic monitoring.

PubMed

Zapata, Lina M; Bock, Brian C; Orozco, Luz Yaneth; Palacio, Jaime A

2016-05-01

Trachemys callirostris is a turtle species endemic to northern South America. In northern Colombia it occurs in the middle and lower Magdalena River drainage and its principal tributaries (lower Cauca and San Jorge rivers) and in other minor drainages such as the lower Sinú River. In recent years, industrial, agricultural, and mining activities have altered natural habitats in Colombia where this species occurs, and many of the pollutants released there are known to induce genetic alterations in wildlife species. The micronucleus test and comet assay are two of the most widely used methods to characterize DNA damage induced by physical and chemical agents in wildlife species, but have not been employed previously for genotoxic evaluations in T. callirostris. The goal of this study was to optimize these genotoxic biomarkers for T. callirostris erythrocytes in order to establish levels of DNA damage in this species and thereby evaluate its potential as a sentinel species for monitoring genotoxic effects in freshwater environments in northern Colombia. Both genotoxic techniques were applied on peripheral blood erythrocytes from 20 captive-reared T. callirostris individuals as a negative control, as well as from samples obtained from 49 individuals collected in Magangué (Magdalena River drainage) and 24 individuals collected in Lorica (Sinú River drainage) in northern Colombia. Negative control individuals exhibited a baseline frequency of micronuclei of 0.78±0.58 and baseline values for comet tail length and tail moment of 3.34±0.24µm and 10.70±5.5, respectively. In contrast, samples from both field sites exhibited significantly greater evidence of genotoxic effects for both tests. The mean MN frequencies in the samples from Magangué and Lorica were 8.04±7.08 and 12.19±12.94, respectively. The mean tail length for samples from Magangué and Lorica were 5.78±3.18 and 15.46±7.39, respectively. Finally, the mean tail moment for samples from Magangué and Lorica were 23.59±18.22 and 297.94±242.18, respectively. The frequency of micronuclei in the samples was positively related to comet tail length and tail moment. Thus, this study showed that both genotoxicity biomarkers may be applied to T. callirostris erythrocytes as a sentinel organism for assessing the effects of environmental pollutants in freshwater ecosystems in northern South America. Copyright © 2016 Elsevier Inc. All rights reserved.

Tests of biocompatibility of alpha-tocopherol with respect to the use as a stabilizer in ultrahigh molecular weight polyethylene for articulating surfaces in joint endoprostheses.

PubMed

Wolf, C; Lederer, K; Müller, U

2002-07-01

To inhibit the oxidation in vivo of hip-cups made of ultrahigh molecular weight polyethylene (UHMW-PE), the natural antioxidant alpha-tocopherol was added to the polymer. The added alpha-tocopherol may however undergo chemical transformations during manufacturing and sterilization by gamma-irradiation of hip-cups which may differ from human metabolism. Therefore, the question of the biocompatibility of the respective transformation products was investigated on test samples, which were prepared under the same conditions as applied for the production and sterilization of hip-cups. Thin plates (25 x 18 x 2 mm(3)) were fabricated out of test samples to investigate the cytotoxic activity according to EN 30993-5. In cytotoxicity testing, proliferation, mitochondrial activity and membrane integrity were not influenced by the material. In contrast, cell adhesion and cell spreading were diminished as shown with hemalum staining. In order to investigate the genotoxicity, the alpha-tocopherol and its transformation products were extracted from test specimens by n-heptane at 185 degrees C under nitrogen atmosphere. Then the n-heptane was evaporated in vacuo and the remaining alpha-tocopherol and its transformation products were dissolved in DMSO. The genotoxicity of this extract was then tested by the Ames-test according to DIN UA 12 (1995), which showed no indication for genotoxic activity.

Selective advantage of resistant strains at trace levels of antibiotics: a simple and ultrasensitive color test for detection of antibiotics and genotoxic agents.

PubMed

Liu, Anne; Fong, Amie; Becket, Elinne; Yuan, Jessica; Tamae, Cindy; Medrano, Leah; Maiz, Maria; Wahba, Christine; Lee, Catherine; Lee, Kim; Tran, Katherine P; Yang, Hanjing; Hoffman, Robert M; Salih, Anya; Miller, Jeffrey H

2011-03-01

Many studies have examined the evolution of bacterial mutants that are resistant to specific antibiotics, and many of these focus on concentrations at and above the MIC. Here we ask for the minimum concentration at which existing resistant mutants can outgrow sensitive wild-type strains in competition experiments at antibiotic levels significantly below the MIC, and we define a minimum selective concentration (MSC) in Escherichia coli for two antibiotics, which is near 1/5 of the MIC for ciprofloxacin and 1/20 of the MIC for tetracycline. Because of the prevalence of resistant mutants already in the human microbiome, allowable levels of antibiotics to which we are exposed should be below the MSC. Since this concentration often corresponds to low or trace levels of antibiotics, it is helpful to have simple tests to detect such trace levels. We describe a simple ultrasensitive test for detecting the presence of antibiotics and genotoxic agents. The test is based on the use of chromogenic proteins as color markers and the use of single and multiple mutants of Escherichia coli that have greatly increased sensitivity to either a wide range of antibiotics or specific antibiotics, antibiotic families, and genotoxic agents. This test can detect ciprofloxacin at 1/75 of the MIC.

Investigation of flurbiprofen genotoxicity and cytotoxicity in rat bone marrow cells.

PubMed

Timocin, Taygun; Ila, Hasan B

2015-01-01

This study was performed to investigate cytogenetic effects of NSAID flurbiprofen which was used as active ingredient in some analgesic, antipyretic and anti-inflammatory drugs. Genotoxic effect of flurbiprofen was investigated using in vivo chromosome aberration (CA) test and random amplified polymorphic DNA-polymerase chain reaction (RAPD-PCR) test. Also, oxidative stress potential of flurbiprofen was determined by measuring total oxidant and antioxidant level which occurred with flurbiprofen treatment in rat peripheral blood. For these purposes, rats were treated with three concentrations of flurbiprofen (29.25, 58.50 and 117 mg/kg, body weight) in single dose at two different treatment periods (12 and 24 h). According to the results, flurbiprofen did not affect chromosome aberrations in rat bone marrow cells with CA test. In RAPD-PCR test, polymorphic bands were unaffected. Also, test substance did not change total oxidant and antioxidant status (except for 58.50 and 117 mg/kg, 12 h) and therefore it did not lead to significant increase on oxidative stress (again except 58.50 and 117 mg/kg, 12 h). However, flurbiprofen reduced to mitotic indexes and these reductions were dose-dependent for 12 h treatment. In summary, flurbiprofen did not show significant genotoxic effect. But it caused cytotoxicity in rat bone marrow cells.

Assessment of the Microscreen phage-induction assay for screening hazardous wastes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Houk, V.S.; DeMarini, D.M.

1987-09-01

The Microscreen phage-induction assay, which quantitatively measures the induction of prophage lambda in Escherichia coli WP2s(lambda), was used to test 14 crude (unfractionated) hazardous industrial waste samples for genotoxic activity in the presence and absence of metabolic activation. Eleven of the 14 wastes induced prophage, and induction was observed at concentrations as low as 0.4 picograms per ml. Comparisons between the mutagenicity of these waste samples in Salmonella and their ability to induce prophage lambda indicate that the Microscreen phage-induction assay detected genotoxic activity in all but one of the wastes that were mutagenic in Salmonella. Moreover, the Microscreen assaymore » detected as genotoxic 5 additional wastes that were not detected in the Salmonella assay. The applicability of the Microscreen phage-induction assay for screening hazardous wastes for genotoxic activity is discussed along with some of the problems associated with screening highly toxic wastes containing toxic volatile compounds.« less

Assessment of the in vivo genotoxicity of cadmium chloride, chloroform, and D,L-menthol as coded test chemicals using the alkaline comet assay.

PubMed

Wada, Kunio; Fukuyama, Tomoki; Nakashima, Nobuaki; Matsumoto, Kyomu

2015-07-01

As part of the Japanese Center for the Validation of Alternative Methods (JaCVAM) international validation study of in vivo rat alkaline comet assays, we examined cadmium chloride, chloroform, and D,L-menthol under blind conditions as coded chemicals in the liver and stomach of Sprague-Dawley rats after 3 days of administration. Cadmium chloride showed equivocal responses in the liver and stomach, supporting previous reports of its poor mutagenic potential and non-carcinogenic effects in these organs. Treatment with chloroform, which is a non-genotoxic carcinogen, did not induce DNA damage in the liver or stomach. Some histopathological changes, such as necrosis and degeneration, were observed in the liver; however, they did not affect the comet assay results. D,L-Menthol, a non-genotoxic non-carcinogen, did not induce liver or stomach DNA damage. These results indicate that the comet assay can reflect genotoxic properties under blind conditions. Copyright © 2015 Elsevier B.V. All rights reserved.

Regulatory requirements for genotoxicity assessment of plant protection product active ingredients, impurities, and metabolites.

PubMed

Booth, Ewan D; Rawlinson, Paul J; Maria Fagundes, Priscila; Leiner, Kevin A

2017-06-01

Active ingredients in plant protection products are subject to rigorous safety assessment during their development, including assessment of genotoxicity. Plant protection products are used for agriculture in multiple regions and for the registration of active ingredients it is necessary to satisfy the data requirements of these different regions. There are no overarching global agreements on which genotoxicity studies need to be conducted to satisfy the majority of regulatory authorities. The implementation of new OECD guidelines for the in vitro micronucleus, transgenic rodent somatic and germ cell gene mutation and in vivo comet assays, as well as the revision of a number of other OECD test guidelines has resulted in some changes to data requirements. This review describes the genotoxicity data requirements for chemical active ingredients as well as biologicals, microbials, ground water metabolites, metabolites, and impurities in a number of regions. Similarities and differences are highlighted. Environ. Mol. Mutagen. 58:325-344, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

In situ assessment of pesticide genotoxicity in an integrated pest management program: II. Maize waxy mutation assay.

PubMed

Rodrigues, G S; Pimentel, D; Weinstein, L H

1998-02-13

The mutagenicity induced by pesticides applied in an integrated pest management (IPM) program was evaluated in situ with the maize forward waxy mutation bioassay. Three pesticide application rates were prescribed as follows: (1) Low--no field pesticide spray; (2) Medium--IPM test rate: banded cyanazine plus metolachlor (2.7 kg a.i. and 2.3 l a.i./ha of herbicides, respectively); and (3) High--a preventative pesticide application program: broadcast cyanazine plus metolachlor (same application rates as above) plus chlorpyrifos (1 kg a.i./ha of insecticide). In general, there was no significant reduction in the genotoxic effects from the high to the medium treatment levels of the IPM program. This suggests that the reduction in pesticide application rates attained with the implementation of the proposed IPM program was not sufficient to abate the genotoxicity of the pesticides. The results indicate that replacing genotoxic compounds may be the only effective remediation measure if concern about environmental mutagenesis were to result in changes in agricultural management.

Genotoxicity studies in groundwater, surface waters, and contaminated soil.

PubMed

Verschaeve, Luc

2002-05-08

It is at present considered important to include biological tests in measuring programmes of environmental samples to supplement the chemical and physical parameters that are currently used. A battery of tests is therefore necessary, also within a given "endpoint" (e.g., genotoxicity), because one single test will not give all the answers to our questions. As it is not possible to include all available tests in routine screening programmes, a selection of tests should be made. According to comparative investigations, the bacterial Ames test remains very important. When no preconcentration step is involved, other bacterial tests (e.g., the umu-C and VITOTOX tests) may be recommended. The comet assay may be used in Daphnia or human white blood cells. Further validations, comparisons, mechanistic investigations, etc. remain necessary as differences are often found between the tests that are not solely explained by differences in genetic endpoint and that therefore should further be investigated and understood.

Comparative cytotoxic and genotoxic potential of 13 drinking water disinfection by-products using a microplate-based cytotoxicity assay and a developed SOS/umu assay.

PubMed

Zhang, Shao-Hui; Miao, Dong-Yue; Tan, Li; Liu, Ai-Lin; Lu, Wen-Qing

2016-01-01

The implications of disinfection by-products (DBPs) present in drinking water are of public health concern because of their potential mutagenic, carcinogenic and other toxic effects on humans. In this study, we selected 13 main DBPs found in drinking water to quantitatively analyse their cytotoxicity and genotoxicity using a microplate-based cytotoxicity assay and a developed SOS/umu assay in Salmonella typhimurium TA1535/pSK1002. With the developed SOS/umu test, eight DBPs: 3-chloro-4-(dichloromethyl)-5-hydroxy-2[5H]-fura3-chloro-4-(dichloromethyl)-5-hydroxy-2-[5H]-furanone (MX), dibromoacetonitrile (DBN), iodoacetic acid (IA), bromochloroacetonitrile (BCN), bromoacetic acid (BA), trichloroacetonitrile (TCN), dibromoacetic acid (DBA) and dichloroacetic acid (DCA) were significantly genotoxic to S. typhimurium. Three DBPs: chloroacetic acid (CA), trichloroacetic acid (TCA) and dichloroacetonitrile (DCN) were weakly genotoxic, whereas the remaining DBPs: chloroacetonitrile (CN) and chloral hydrate (CH) were negative. The rank order in decreasing genotoxicity was as follows: MX > DBN > IA > BCN > BA > TCN > DBA > DCA > CA, TCA, DCN > CN, CH. MX was approximately 370 000 times more genotoxic than DCA. In the microplate-based cytotoxicity assay, cytotoxic potencies of the 13 DBPs were compared and ranked in decreasing order as follows: MX > IA > DBN > BCN > BA > TCN > DCN > CA > DCA > DBA > CN > TCA > CH. MX was approximately 19 200 times more cytotoxic than CH. A statistically significant correlation was found between cytotoxicity and genotoxicity of the 13 DBPs in S. typhimurium. Results suggest that microplate-based cytotoxicity assay and the developed SOS/umu assay are feasible tools for analysing the cytotoxicity and genotoxicity of DBPs, particularly for comparing their toxic intensities quantitatively. © The Author 2015. Published by Oxford University Press on behalf of the UK Environmental Mutagen Society. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Monitoring hospital wastewaters for their probable genotoxicity and mutagenicity.

PubMed

Sharma, Pratibha; Mathur, N; Singh, A; Sogani, M; Bhatnagar, P; Atri, R; Pareek, S

2015-01-01

Cancer is a leading cause of death worldwide. Excluding the genetic factors, environmental factors, mainly the pollutants, have been implicated in the causation of the majority of cancers. Wastewater originated from health-care sectors such as hospitals may carry vast amounts of carcinogenic and genotoxic chemicals to surface waters or any other source of drinking water, if discharged untreated. Humans get exposed to such contaminants through a variety of ways including drinking water. The aim of the present study was, thus, to monitor the genotoxic and mutagenic potential of wastewaters from three big hospitals located in Jaipur (Rajasthan), India. One of them was operating an effluent treatment plant (ETP) for treatment of its wastewater and therefore both the untreated and treated effluents from this hospital were studied for their genotoxicity. Two short-term bacterial bioassays namely the Salmonella fluctuation assay and the SOS chromotest were used for the purpose. Results of fluctuation assay revealed the highly genotoxic nature of all untreated effluent samples with mutagenicity ratios (MR) up to 23.13 ± 0.18 and 42.25 ± 0.35 as measured with Salmonella typhimurium strains TA98 and TA100, respectively. As determined with the chromotest, all untreated effluents produced significant induction factors (IF) ranging from 3.29 ± 1.11 to 13.35 ± 3.58 at higher concentrations. In contrast, treated effluent samples were found to be slightly genotoxic in fluctuation test only with an MR = 3.75 ± 0.35 for TA100 at 10 % concentration. Overall, the results indicated that proper treatment of hospital wastewaters may render the effluents safe for disposal contrary to the untreated ones, possessing high genotoxic potential.

Prediction model of potential hepatocarcinogenicity of rat hepatocarcinogens using a large-scale toxicogenomics database

DOE Office of Scientific and Technical Information (OSTI.GOV)

Uehara, Takeki, E-mail: takeki.uehara@shionogi.co.jp; Toxicogenomics Informatics Project, National Institute of Biomedical Innovation, 7-6-8 Asagi, Ibaraki, Osaka 567-0085; Minowa, Yohsuke

2011-09-15

The present study was performed to develop a robust gene-based prediction model for early assessment of potential hepatocarcinogenicity of chemicals in rats by using our toxicogenomics database, TG-GATEs (Genomics-Assisted Toxicity Evaluation System developed by the Toxicogenomics Project in Japan). The positive training set consisted of high- or middle-dose groups that received 6 different non-genotoxic hepatocarcinogens during a 28-day period. The negative training set consisted of high- or middle-dose groups of 54 non-carcinogens. Support vector machine combined with wrapper-type gene selection algorithms was used for modeling. Consequently, our best classifier yielded prediction accuracies for hepatocarcinogenicity of 99% sensitivity and 97% specificitymore » in the training data set, and false positive prediction was almost completely eliminated. Pathway analysis of feature genes revealed that the mitogen-activated protein kinase p38- and phosphatidylinositol-3-kinase-centered interactome and the v-myc myelocytomatosis viral oncogene homolog-centered interactome were the 2 most significant networks. The usefulness and robustness of our predictor were further confirmed in an independent validation data set obtained from the public database. Interestingly, similar positive predictions were obtained in several genotoxic hepatocarcinogens as well as non-genotoxic hepatocarcinogens. These results indicate that the expression profiles of our newly selected candidate biomarker genes might be common characteristics in the early stage of carcinogenesis for both genotoxic and non-genotoxic carcinogens in the rat liver. Our toxicogenomic model might be useful for the prospective screening of hepatocarcinogenicity of compounds and prioritization of compounds for carcinogenicity testing. - Highlights: >We developed a toxicogenomic model to predict hepatocarcinogenicity of chemicals. >The optimized model consisting of 9 probes had 99% sensitivity and 97% specificity. >This model enables us to detect genotoxic as well as non-genotoxic hepatocarcinogens.« less

Environmental stress in the Gulf of Mexico and its potential impact on public health

PubMed Central

Turner, J.; Walter, L.; Lathan, N.; Thorpe, D.; Ogbevoen, P.; Daye, J.; Alcorn, D.; Wilson, S.; Semien, J.; Richard, T.; Johnson, T.; McCabe, K.; Estrada, J.J.; Galvez, F.; Velasco, C.; Reiss, K.

2017-01-01

The Deepwater Horizon (DWH) oil spill in the Gulf of Mexico was the largest maritime oil spill in history resulting in the accumulation of genotoxic substances in the air, soil, and water. This has potential far-reaching health impacts on cleanup field workers and on the populations living in the contaminated coastal areas. We have employed portable airborne particulate matter samplers (SKC Biosampler Impinger) and a genetically engineered bacterial reporter system (umu-ChromoTest from EBPI) to determine levels of genotoxicity of air samples collected from highly contaminated areas of coastal Louisiana including Grand Isle, Port Fourchon, and Elmer's Island in the spring, summer and fall of 2011, 2012, 2013 and 2014. Air samples collected from a non-contaminated area, Sea Rim State Park, Texas, served as a control for background airborne genotoxic particles. In comparison to controls, air samples from the contaminated areas demonstrated highly significant increases in genotoxicity with the highest values registered during the month of July in 2011, 2013, and 2014, in all three locations. This seasonal trend was disrupted in 2012, when the highest genotoxicity values were detected in October, which correlated with hurricane Isaac landfall in late August of 2012, about five weeks before a routine collection of fall air samples. Our data demonstrate: (i) high levels of air genotoxicity in the monitored areas over last four years post DWH oil spill; (ii) airborne particulate genotoxicity peaks in summers and correlates with high temperatures and high humidity; and (iii) this seasonal trend was disrupted by the hurricane Isaac landfall, which further supports the concept of a continuous negative impact of the oil spill in this region. PMID:26745734

Environmental stress in the Gulf of Mexico and its potential impact on public health.

PubMed

Singleton, B; Turner, J; Walter, L; Lathan, N; Thorpe, D; Ogbevoen, P; Daye, J; Alcorn, D; Wilson, S; Semien, J; Richard, T; Johnson, T; McCabe, K; Estrada, J J; Galvez, F; Velasco, C; Reiss, K

2016-04-01

The Deepwater Horizon (DWH) oil spill in the Gulf of Mexico was the largest maritime oil spill in history resulting in the accumulation of genotoxic substances in the air, soil, and water. This has potential far-reaching health impacts on cleanup field workers and on the populations living in the contaminated coastal areas. We have employed portable airborne particulate matter samplers (SKC Biosampler Impinger) and a genetically engineered bacterial reporter system (umu-ChromoTest from EBPI) to determine levels of genotoxicity of air samples collected from highly contaminated areas of coastal Louisiana including Grand Isle, Port Fourchon, and Elmer's Island in the spring, summer and fall of 2011, 2012, 2013 and 2014. Air samples collected from a non-contaminated area, Sea Rim State Park, Texas, served as a control for background airborne genotoxic particles. In comparison to controls, air samples from the contaminated areas demonstrated highly significant increases in genotoxicity with the highest values registered during the month of July in 2011, 2013, and 2014, in all three locations. This seasonal trend was disrupted in 2012, when the highest genotoxicity values were detected in October, which correlated with hurricane Isaac landfall in late August of 2012, about five weeks before a routine collection of fall air samples. Our data demonstrate: (i) high levels of air genotoxicity in the monitored areas over last four years post DWH oil spill; (ii) airborne particulate genotoxicity peaks in summers and correlates with high temperatures and high humidity; and (iii) this seasonal trend was disrupted by the hurricane Isaac landfall, which further supports the concept of a continuous negative impact of the oil spill in this region. Copyright © 2015 Elsevier Inc. All rights reserved.

Identification and assessment of hazardous compounds in drinking water.

PubMed

Fawell, J K; Fielding, M

1985-12-01

The identification of organic chemicals in drinking water and their assessment in terms of potential hazardous effects are two very different but closely associated tasks. In relation to both continuous low-level background contamination and specific, often high-level, contamination due to pollution incidents, the identification of contaminants is a pre-requisite to evaluation of significant hazards. Even in the case of the rapidly developing short-term bio-assays which are applied to water to indicate a potential genotoxic hazard (for example Ames tests), identification of the active chemicals is becoming a major factor in the further assessment of the response. Techniques for the identification of low concentrations of organic chemicals in drinking water have developed remarkably since the early 1970s and methods based upon gas chromatography-mass spectrometry (GC-MS) have revolutionised qualitative analysis of water. Such techniques are limited to "volatile" chemicals and these usually constitute a small fraction of the total organic material in water. However, in recent years there have been promising developments in techniques for "non-volatile" chemicals in water. Such techniques include combined high-performance liquid chromatography-mass spectrometry (HPLC-MS) and a variety of MS methods, involving, for example, field desorption, fast atom bombardment and thermospray ionisation techniques. In the paper identification techniques in general are reviewed and likely future developments outlined. The assessment of hazards associated with chemicals identified in drinking and related waters usually centres upon toxicology - an applied science which involves numerous disciplines. The paper examines the toxicological information needed, the quality and deployment of such information and discusses future research needs. Application of short-term bio-assays to drinking water is a developing area and one which is closely involved with, and to some extent dependent on, powerful methods of identification. Recent developments are discussed.

The utility of the in vitro micronucleus test for evaluating the genotoxicity of natural and manmade nano-scale fibres.

PubMed

Fowler, Paul; Homan, Andrew; Atkins, Derek; Whitwell, James; Lloyd, Melvyn; Bradford, Roberta

2016-10-01

A range of fibrous materials, including several types of asbestos and carbon fibres with nano scale diameters that had reported positive genotoxicity data (predominantly clastogenicity), were tested in the in vitro micronucleus test (OECD 487) in GLP-compliant studies in Chinese Hamster Ovary cells. Out of eight materials tested, only one (crocidolite, an asbestos fibre) gave a positive response either in the presence or absence of metabolic activation (S9) and at short (3h) or extended (24h) exposure times (p≤0.001). Our data suggest that the commonly used tests for clastogenicity in mammalian cells require extensive modification before fibrous materials are detected as positive, raising questions about the validity of these tests for detecting clastogenic and aneugenic fibrous materials. Copyright © 2016 Elsevier B.V. All rights reserved.

Anti-genotoxic effect of naringin against bleomycin-induced genomic damage in human lymphocytes in vitro.

PubMed

Yilmaz, Dilek; Teksoy, Ozgun; Bilaloglu, Rahmi; Çinkilic, Nilufer

2016-01-01

Naringin is a flavonoid found in grapefruit and other citrus fruits that shows antioxidant activity. The aim of the present study was to determine the anti-genotoxic and protective effects of naringin on the chemotherapeutic/radiomimetic agent bleomycin (BLM) in human blood lymphocyte cultures in vitro using micronucleus test and chromosomal aberrations (CA) assay. We tested the three doses of naringin (1, 2, 3 µg/mL) and a single dose of BLM (20 µg/mL). BLM significantly increased the total CAs and micronucleus frequency at a concentration of 20 µg/mL. Naringin did not show any toxicity in doses of 1, 2, and 3 µg/mL. Combined treatments of BLM and naringin (2 and 3 µg/mL) significantly reduced micronucleus formation. Naringin dose-dependently decreased the total chromosome aberrations frequency induced by BLM. These results indicate that naringin could prevent BLM (20 µg/mL)-induced genotoxicity.

Evaluation of Cytotoxicity and Genotoxicity of Acacia aroma Leaf Extracts

PubMed Central

Mattana, C. M.; Cangiano, M. A.; Alcaráz, L. E.; Sosa, A.; Escobar, F.; Sabini, C.; Sabini, L.; Laciar, A. L.

2014-01-01

Acacia aroma, native plant from San Luis, Argentina, is commonly used as antiseptic and for healing of wounds. The present study was conducted to investigate the in vitro cytotoxicity and genotoxicity of hot aqueous extract (HAE) and ethanolic extract (EE) of A. aroma. The cytotoxic activity was assayed by neutral red uptake assay on Vero cell. Cell treatment with a range from 100 to 5000 μg/mL of HAE and EE showed that 500 μg/mL and 100 μg/mL were the maximum noncytotoxic concentrations, respectively. The CC50 was 658 μg/mL for EE and 1020 μg/mL for HAE. The genotoxicity was tested by the single-cell gel electrophoresis comet assay. The results obtained in the evaluation of DNA cellular damage exposed to varied concentrations of the HAE showed no significant genotoxic effect at range of 1–20 mg/mL. The EE at 20 mg/mL showed moderate genotoxic effect related to the increase of the DNA percentage contained in tail of the comet; DNA was classified in category 2. At concentrations below 5 mg/mL, the results of cytotoxicity and genotoxicity of aqueous and ethanolic extracts of Acacia aroma guarantee the safety at cell and genomic level. However further studies are needed for longer periods including animal models to confirm the findings. PMID:25530999

Influence of Serum Levels of Vitamins A, D, and E as well as Vitamin D Receptor Polymorphisms on Micronucleus Frequencies and Other Biomarkers of Genotoxicity in Workers Exposed to Formaldehyde.

PubMed

Ladeira, Carina; Pádua, Mário; Veiga, Luísa; Viegas, Susana; Carolino, Elisabete; Gomes, Manuel C; Brito, Miguel

2015-01-01

Formaldehyde is classified as carcinogenic to humans, making it a major concern, particularly in occupational settings. Fat-soluble vitamins, such as vitamins A, D, and E, are documented as antigenotoxic and antimutagenic and also correlate with the cell antioxidant potential. This study investigates the influence of these vitamins on genotoxicity biomarkers of formaldehyde-exposed hospital workers. The target population were hospital workers exposed to formaldehyde (n = 55). Controls were nonexposed individuals (n = 80). The most used genotoxicity biomarkers were the cytokinesis-block micronucleus assay for lymphocytes and the micronucleus test for exfoliated buccal cells. Vitamins A and E were determined by high-performance liquid chromatography with a diode array detector (HPLC-DAD) and vitamin D receptor (VDR) polymorphisms by real-time PCR. Significant correlations were found between genotoxicity biomarkers and between vitamins A and E in controls. Multiple regression showed that vitamin A was significantly associated with a higher mean of nucleoplasmic bridges (p < 0.001), and vitamin E was significantly associated with a decreased frequency of nuclear buds (p = 0.045) in the exposed group. No effect of vitamin D was observed. The VDRBsmI TT genotype carriers presented higher means of all the genotoxicity biomarkers; however, we found no significant associations. The study suggests that vitamin levels may modulate direct signs of genotoxicity. © 2016 S. Karger AG, Basel.

Genotoxicity of carbon nanofibers: Are they potentially more or less dangerous than carbon nanotubes or asbestos?

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kisin, E.R.; Murray, A.R.; Sargent, L.

The production of carbon nanofibers and nanotubes (CNF/CNT) and their composite products is increasing globally. CNF are generating great interest in industrial sectors such as energy production and electronics, where alternative materials may have limited performance or are produced at a much higher cost. However, despite the increasing industrial use of carbon nanofibers, information on their potential adverse health effects is limited. In the current study, we examine the cytotoxic and genotoxic potential of carbon-based nanofibers (Pyrograf (registered) -III) and compare this material with the effects of asbestos fibers (crocidolite) or single-walled carbon nanotubes (SWCNT). The genotoxic effects in themore » lung fibroblast (V79) cell line were examined using two complementary assays: the comet assay and micronucleus (MN) test. In addition, we utilized fluorescence in situ hybridization to detect the chromatin pan-centromeric signals within the MN indicating their origin by aneugenic (chromosomal malsegregation) or clastogenic (chromosome breakage) mechanisms. Cytotoxicity tests revealed a concentration- and time-dependent loss of V79 cell viability after exposure to all tested materials in the following sequence: asbestos > CNF > SWCNT. Additionally, cellular uptake and generation of oxygen radicals was seen in the murine RAW264.7 macrophages following exposure to CNF or asbestos but not after administration of SWCNT. DNA damage and MN induction were found after exposure to all tested materials with the strongest effect seen for CNF. Finally, we demonstrated that CNF induced predominately centromere-positive MN in primary human small airway epithelial cells (SAEC) indicating aneugenic events. Further investigations are warranted to elucidate the possible mechanisms involved in CNF-induced genotoxicity.« less

Evaluation of genotoxic and antigenotoxic effects of boron by the somatic mutation and recombination test (SMART) on Drosophila.

PubMed

Sarıkaya, Rabia; Erciyas, Kamile; Kara, Muhammed Isa; Sezer, Ufuk; Erciyas, Ali Fuat; Ay, Sinan

2016-10-01

In this study, different concentrations of boron have been evaluated for genotoxic and antigenotoxic properties by using the somatic mutation and recombination test (SMART) on Drosophila melanogaster. The treatment concentrations were chosen to a pretest. Third-instar larvae trans-heterozygous for two genetic markers, multiple wing hair (mwh) and flare (flr3), were treated at different concentrations (0.1, 5, 10, 20, and 40 mg/mL) of boron. In addition to investigating antigenotoxic effects, the same boron concentrations were co-administered with 0.1 mM Ethyl Methane Sulfonate (EMS). Distilled water was used as a negative control; 0.1 mM of EMS was used as a positive control. For the chronic feeding study, small plastic vials were prepared with 1.5 g of dry Drosophila Instant Medium and 5 mL of the respective test solution. Hundreds of trans-heterozygous larvae were embedded into this medium. Feeding ended with pupation of the surviving larvae. After metamorphosis, all surviving flies were collected and stored in a 70% ethanol solution. Preparation and microscopic analyses of wing were made after the treatment. Then the observed mutations were classified according to size and type of mutation per wing. Results indicated that there is no significant genotoxic effect with all of the boron concentrations. In addition, the antigenotoxic activities of boron against EMS were tested. Results indicated that all boron concentrations (0.1, 5, 10, 20 and 40 mg/mL) were able to abolish the genotoxic effects induced by the EMS. It is suggested that the observed effects can be linked to the antioxidant properties of boron. Moreover, these in vivo results will contribute to the antigenotoxicity database of boron.

Effects of indirubin and isatin on cell viability, mutagenicity, genotoxicity and BAX/ERCC1 gene expression.

PubMed

Fogaça, Manoela Viar; Cândido-Bacani, Priscila de Matos; Benicio, Lucas Milanez; Zapata, Lara Martinelli; Cardoso, Priscilla de Freitas; de Oliveira, Marcelo Tempesta; Calvo, Tamara Regina; Varanda, Eliana Aparecida; Vilegas, Wagner; de Syllos Cólus, Ilce Mara

2017-12-01

Indigofera suffruticosa Miller (Fabaceae) and I. truxillensis Kunth produce compounds, such as isatin (ISA) and indirubin (IRN), which possess antitumour properties. Their effects in mammalian cells are still not very well understood. We evaluated the activities of ISA and/or IRN on cell viability and apoptosis in vitro, their genotoxic potentials in vitro and in vivo, and the IRN- and ISA-induced expression of ERCC1 or BAX genes. HeLa and/or CHO-K1 cell lines were tested (3 or 24 h) in the MTT, Trypan blue exclusion, acridine orange/ethidium bromide, cytokinesis-blocked micronucleus (CBMN) and comet (36, 24 and 72 h) tests after treatment with IRN (0.1 to 200 μM) or ISA (0.5 to 50 μM). Gene expression was measured by RT-qPCR in HeLa cells. Swiss albino mice received IRN (3, 4 or 24 h) by gavage (50, 100 and 150 mg/kg determined from the LD 50 - 1 g/kg b.w.) and submitted to comet assay in vivo. IRN reduced the viability of CHO-K1 (24 h; 5 to 200 μM) and HeLa cells (10 to 200 μM), and was antiproliferative in the CBMN test (CHO-K1: 0.5 to 10 μM; HeLa: 5 and 10 μM). The drug did not induce apoptosis, micronucleus neither altered gene expression. IRN and ISA were genotoxic for HeLa cells (3 and 24 h) at all doses tested. IRN (100 and 150 mg/kg) also induced genotoxicity in vivo (4 h). IRN and ISA have properties that make them candidates as chemotherapeutics for further pharmacological investigations.

Evaluation of the Bronchorelaxant, Genotoxic, and Antigenotoxic Effects of Cassia alata L.

PubMed Central

Ouédraogo, M.; Da, F. L.; Fabré, A.; Konaté, K.; Dibala, C. I.; Carreyre, H.; Thibaudeau, S.; Coustard, J.-M.; Vandebrouck, C.; Bescond, J.; Belemtougri, R. G.

2013-01-01

Aqueous-ethanolic extract of Cassia alata (AECal) and its derived fractions obtained through liquid-liquid fractionation were evaluated for their bronchorelaxant, genotoxic, and antigenotoxic effects. Contractile activity of rats' tracheas in the presence of tested materials, as well as its modifications with different inhibitors and blockers, was isometrically recorded. The antigenotoxic potential of AECal was evaluated on cyclophosphamide- (CP-) induced genotoxicity in the rat. Animals were pretreated with the extract, then liver comet assay was performed. AECal and its chloroformic fractions (CF-AECal) relaxed the contraction induced by Ach, but both were significantly less potent in inhibiting contraction induced by KCl (30 mM; 80 mM). Propranolol, indomethacin, L-NAME, methylene blue, and glibenclamide did not modify the relaxant effect of CF-AECal. TEA altered the response of trachea to CF-AECal. CF-AECal caused a rightward shift without affecting the E max in cumulative concentration-response curves of Ach only at low concentrations. In animals pretreated with the extract, the percentage of CP-induced DNA damage decreased. Our results suggest that (1) muscarinic receptors contribute at least in part to the relaxant effects of CF-AECal; (2) CF-AECal interferes with membrane polarization; and (3) AECal is not genotoxic in vivo and contains chemopreventive phytoconstituents offering protection against CP-induced genotoxicity. PMID:23710211

Evaluation of genotoxic effects caused by extracts of chlorinated drinking water using a combination of three different bioassays.

PubMed

Zeng, Qiang; Zhang, Shao-Hui; Liao, Jing; Miao, Dong-Yue; Wang, Xin-Yi; Yang, Pan; Yun, Luo-Jia; Liu, Ai-Lin; Lu, Wen-Qing

2015-10-15

Potential genotoxic effects of chlorinated drinking water now are of a great concern. In this study, raw water, finished water, and tap water from a water plant in Wuhan, China were collected in two different sampling times of the year (January and July). Genotoxic effects of water extracts were evaluated using a combination of three different bioassays: SOS/umu test, HGPRT gene mutation assay, and micronucleus assay, which were separately used to detect DNA damage, gene mutation, and chromosome aberration. The results of three different bioassays showed that all water samples in January and July induced at least one types of genotoxic effects, of which the DNA-damage effects were all detectable. The levels of DNA-damage effects and gene-mutation effects of finished water and tap water in January were higher than those in July. Chlorination could increase the DNA-damage effects of drinking water in January and the gene-mutation effects of drinking water in both January and July, but did not increase the chromosome-aberration effects of drinking water in both January and July. Our results highlighted the importance of using a combination of different bioassays to evaluate the genotoxicity of water samples in different seasons. Copyright © 2015 Elsevier B.V. All rights reserved.

Chemical composition and genotoxicity assessment of sanitary landfill leachate from Rovinj, Croatia.

PubMed

Gajski, Goran; Oreščanin, Višnja; Garaj-Vrhovac, Vera

2012-04-01

Chemical analysis and an in vitro approach were performed to assess elemental composition and genotoxic effects of the samples of landfill leachate taken from Lokva Vidotto sanitary landfill the official landfill for Rovinj town, Croatia. Two samples of landfill leachate were collected and analyzed in order to evaluate macro, micro and trace elements by atomic absorption spectroscopy, energy dispersive X-ray spectrometry and colorimetry. Genotoxicity of sanitary landfill leachate was evaluated in human lymphocytes by the use of the micronucleus test and comet assay. Samples were characterized with relatively low concentrations of heavy metals while organic component level exceeded upper permissible limit up to 39 times. Observed genotoxic effects should be connected with high concentrations of ammonia nitrogen, which exceeded permissible limit up to 180 times. Leachate samples of both sanitary landfills increased the frequency of micronuclei, nucleoplasmic bridges and nuclear buds. Increase of DNA damage in human lymphocytes was also detected by virtue of measuring comet assay parameters. All parameters showed statistically significant difference compared to negative control. Increased micronucleus and comet assay parameters indicate that both samples of sanitary landfill leachate are genotoxic and could pose environmental and human health risk if discharged to an aquatic environment. Copyright © 2011 Elsevier Inc. All rights reserved.

Sodium hypochlorite-, chlorine dioxide- and peracetic acid-induced genotoxicity detected by the Comet assay and Saccharomyces cerevisiae D7 tests.

PubMed

Buschini, Annamaria; Carboni, Pamela; Furlini, Mariangela; Poli, Paola; Rossi, Carlo

2004-03-01

Mutagenicity of drinking water is due not only to industrial, agricultural and urban pollution but also to chlorine disinfection by-products. Furthermore, residual disinfection is used to provide a partial safeguard against low level contamination and bacterial re-growth within the distribution system. The aims of this study were to further evaluate the genotoxic potential of the world wide used disinfectants sodium hypochlorite and chlorine dioxide in human leukocytes by the Comet assay and in Saccharomyces cerevisiae strain D7 (mitotic gene conversion, point mutation and mitochondrial DNA mutability, with and without endogenous metabolic activation) and to compare their effects with those of peracetic acid, proposed as an alternative disinfectant. All three disinfectants are weakly genotoxic in human leukocytes (lowest effective dose 0.2 p.p.m. for chlorine dioxide, 0.5 p.p.m. for sodium hypochlorite and peracetic acid). The results in S.cerevisiae show a genotoxic response on the end-points considered with an effect only at doses higher (5- to 10-fold) than the concentration normally used for water disinfection; sodium hypochlorite and peracetic acid are able to induce genotoxic effects without endogenous metabolic activation (in stationary phase cells) whereas chlorine dioxide is effective in growing cells. The Comet assay was more sensitive than the yeast tests, with effective doses in the range normally used for water disinfection processes. The biological effectiveness of the three disinfectants on S.cerevisiae proved to be strictly dependent on cell-specific physiological/biochemical conditions. All the compounds appear to act on the DNA and peracetic acid shows effectiveness similar to sodium hypochlorite and chlorine dioxide.

Oxidative stress and genotoxicity of an organic and an inorganic nanomaterial to Eisenia andrei: SDS/DDAB nano-vesicles and titanium silicon oxide.

PubMed

Correia, Bruno; Lourenço, Joana; Marques, Sérgio; Nogueira, Verónica; Gavina, Ana; da Graça Rasteiro, Maria; Antunes, Filipe; Mendo, Sónia; Pereira, Ruth

2017-06-01

In the past few years the number of studies on the toxic effects of nanomaterials (NMs) in the environment increased significantly. Nonetheless, the data is still scarce, since there is a large number of NMs and new ones are being developed each day. Soils are extremely important for life, and are easily exposed to the released NMs, thus enhanced efforts are needed to study the impacts on soil biota. The objective of the present work was to determine if different concentrations of two NMs, one inorganic (TiSiO 4 ) and other organic (nano-vesicles of sodium sodecyl sulfate/ didodecyl dimethylammonium bromide - SDS/DDAB), are genotoxic to soil invertebrates. Additionally, it was intended to understand whether, in the event of occurring, genotoxicity was caused by the incapability of the cells to deal with the oxidative stress caused by these NMs. With that purpose, Eisenia andrei were exposed for 30 days to the artificial OECD soil contaminated with different concentrations of the NMs being tested. After the exposure, coelomocytes were extracted from earthworms and DNA damage was measured by the comet assay. The activity of antioxidant enzymes (e.g. glutathione peroxidase, glutathione reductase and glutathione-S-Transferase) and lipid peroxidation were also assessed. The results showed that both NMs were genotoxic, particularly TiSiO 4 for which significant DNA damages were recorded for concentrations above 444mg of TiSiO 4 -NM/kg of soil dw . Since no statistically significant differences were found in the tested antioxidant enzymes and in lipid peroxidation, the mechanism of genotoxicity of these NMs seemed to be unrelated with oxidative stress. Copyright © 2017 Elsevier Inc. All rights reserved.

Heated naringin mitigate the genotoxicity effect of Mitomycin C in BALB/c mice through enhancing the antioxidant status.

PubMed

Maatouk, Mouna; Mustapha, Nadia; Mokdad-Bzeouich, Imen; Chaaban, Hind; Ioannou, Irina; Ghedira, Kamel; Ghoul, Mohamed; Chekir-Ghedira, Leila

2018-01-01

A major problem with cancer chemotherapy is its severe toxic effects on non-target tissues. Assessment of natural products for their protective effect against anticancer drugs induced toxicity is gaining importance in cancer biology. The aim of the present study was to evaluate the effect of native and thermal treated naringin on the protective effect against mitomycin C (MMC) induced genotoxicity. The genotoxicity in liver kidney and brain cells isolated from Balb/C mice were evaluated by performing the comet assay. Antioxidant and lipid peroxidation assays were carried out to understand the protective effects of these compounds. The comet assay showed that heated and native naringin were not genotoxic at the tested dose (40 mg/kg b.w) on liver, kidney and brain cells. A significant decrease in DNA damages was observed, at the tested doses (20 mg/kg b.w and 40 mg/kg b.w) suggesting a protective role of these molecules against the genotoxicity induced by mitomycin C on liver, kidney and brain cells. Moreover, administration of MMC (6 mg/kg b.w.) altered the activities of glutathione peroxidase and superoxide dismutase accompanied by a significant increase of lipid peroxidation. Pretreatment of mouse with heated and native naringin before MMC administration significantly raised the glutathione peroxidase and superoxide dismutase activities followed by a reduced MMC-induced lipid peroxidation. Our study demonstrated that heat treatment of naringin preserve activities of native naringin. The genoprotective properties of heated and native naringin against MMC could be attributed to its antioxidant activities and its inhibitory effect on lipid peroxidation. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Genotoxicity biomarkers for airborne particulate matter (PM2.5) in an area under petrochemical influence.

PubMed

Lemos, Andréia Torres; Lemos, Clarice Torres de; Flores, Andressa Negreiros; Pantoja, Eduarda Ozório; Rocha, Jocelita Aparecida Vaz; Vargas, Vera Maria Ferrão

2016-09-01

The effects of fine inhalable particles (PM2.5) were evaluated in an area under the influence of a petrochemical industry, investigating the sensitivity of different genotoxicity biomarkers. Organic extracts were obtained from PM2.5 samples at two sites, positioned in the first and second preferential wind direction in the area. The extracts were evaluated with Salmonella/microsome assay, microsuspension method, strains TA98, YG1021 and YG1024. The mammalian metabolization fraction (S9) was used to evaluate metabolite mutagenicity. The Comet Assay (CA) and Micronuclei Test were used in a Chinese hamster lung cell line (V79). All extracts showed mutagenicity in Salmonella, and nitrogenated compounds were strongly present. Genotoxicity were found in CA in almost all extracts and the micronuclei induction at the Site in the first (Autumn 1, Winter 1), and in the second (Spring 2) wind direction. V79 showed cytotoxicity in all samples. The three biomarkers were concordant in characterization Site NO with worse quality, compatible with the greater pollutants dispersion in the first wind direction. All PM2.5 concentrations were lower than those recommended by air quality standards but genotoxic effects were detected in all samples, corroborating that these standards are inadequate as quality indicators. The Salmonella/microsome assay proved sensitive to PM2.5 mutagenicity, with an outstanding influence of nitroarenes and aromatic amines. Analyses using CA and the micronucleus test broadened the levels of response that involve different damage induction mechanisms. Results show that the complex PM2.5 composition can provoke various genotoxic effects and the use of different bioassays is essential to understand its effects. Copyright © 2016. Published by Elsevier Ltd.

Emerging metrology for high-throughput nanomaterial genotoxicology.

PubMed

Nelson, Bryant C; Wright, Christa W; Ibuki, Yuko; Moreno-Villanueva, Maria; Karlsson, Hanna L; Hendriks, Giel; Sims, Christopher M; Singh, Neenu; Doak, Shareen H

2017-01-01

The rapid development of the engineered nanomaterial (ENM) manufacturing industry has accelerated the incorporation of ENMs into a wide variety of consumer products across the globe. Unintentionally or not, some of these ENMs may be introduced into the environment or come into contact with humans or other organisms resulting in unexpected biological effects. It is thus prudent to have rapid and robust analytical metrology in place that can be used to critically assess and/or predict the cytotoxicity, as well as the potential genotoxicity of these ENMs. Many of the traditional genotoxicity test methods [e.g. unscheduled DNA synthesis assay, bacterial reverse mutation (Ames) test, etc.,] for determining the DNA damaging potential of chemical and biological compounds are not suitable for the evaluation of ENMs, due to a variety of methodological issues ranging from potential assay interferences to problems centered on low sample throughput. Recently, a number of sensitive, high-throughput genotoxicity assays/platforms (CometChip assay, flow cytometry/micronucleus assay, flow cytometry/γ-H2AX assay, automated 'Fluorimetric Detection of Alkaline DNA Unwinding' (FADU) assay, ToxTracker reporter assay) have been developed, based on substantial modifications and enhancements of traditional genotoxicity assays. These new assays have been used for the rapid measurement of DNA damage (strand breaks), chromosomal damage (micronuclei) and for detecting upregulated DNA damage signalling pathways resulting from ENM exposures. In this critical review, we describe and discuss the fundamental measurement principles and measurement endpoints of these new assays, as well as the modes of operation, analytical metrics and potential interferences, as applicable to ENM exposures. An unbiased discussion of the major technical advantages and limitations of each assay for evaluating and predicting the genotoxic potential of ENMs is also provided. Published by Oxford University Press on behalf of the UK Environmental Mutagen Society 2016.

Hazard characterization and identification of a former ammunition site using microarrays, bioassays, and chemical analysis.

PubMed

Eisentraeger, Adolf; Reifferscheid, Georg; Dardenne, Freddy; Blust, Ronny; Schofer, Andrea

2007-04-01

More than 100,000 tons of 2,4,6-trinitrotoluene were produced at the former ammunition site Werk Tanne in Clausthal-Zellerfeld, Germany. The production of explosives and consequent detonation in approximately 1944 by the Allies caused great pollution in this area. Four soil samples and three water samples were taken from this site and characterized by applying chemical-analytical methods and several bioassays. Ecotoxicological test systems, such as the algal growth inhibition assay with Desmodesmus subspicatus, and genotoxicity tests, such as the umu and NM2009 tests, were performed. Also applied were the Ames test, according to International Organization for Standardization 16240, and an Ames fluctuation test. The toxic mode of action was examined using bacterial gene profiling assays with a battery of Escherichia coli strains and with the human liver cell line hepG2 using the PIQOR Toxicology cDNA microarray. Additionally, the molecular mechanism of 2,4,6-trinitrotoluene in hepG2 cells was analyzed. The present assessment indicates a danger of pollutant leaching for the soil-groundwater path. A possible impact for human health is discussed, because the groundwater in this area serves as drinking water.

Compounds used to produce cloned animals are genotoxic and mutagenic in mammalian assays in vitro and in vivo

PubMed Central

Oliveira, R.J.; Mantovani, M.S.; da Silva, A.F.; Pesarini, J.R.; Mauro, M.O.; Ribeiro, L.R.

2014-01-01

The compounds 6-dimethylaminopurine and cycloheximide promote the successful production of cloned mammals and have been used in the development of embryos produced by somatic cell nuclear transfer. This study investigated the effects of 6-dimethylaminopurine and cycloheximide in vitro, using the thiazolyl blue tetrazolium bromide colorimetric assay to assess cytotoxicity, the trypan blue exclusion assay to assess cell viability, the comet assay to assess genotoxicity, and the micronucleus test with cytokinesis block to test mutagenicity. In addition, the comet assay and the micronucleus test were also performed on peripheral blood cells of 54 male Swiss mice, 35 g each, to assess the effects of the compounds in vivo. The results indicated that both 6-dimethylaminopurine and cycloheximide, at the concentrations and doses tested, were cytotoxic in vitro and genotoxic and mutagenic in vitro and in vivo, altered the nuclear division index in vitro, but did not diminish cell viability in vitro. Considering that alterations in DNA play important roles in mutagenesis, carcinogenesis, and morphofunctional teratogenesis and reduce embryonic viability, this study indicated that 6-dimethylaminopurine and cycloheximide utilized in the process of mammalian cloning may be responsible for the low embryo viability commonly seen in nuclear transfer after implantation in utero. PMID:24714812

Compounds used to produce cloned animals are genotoxic and mutagenic in mammalian assays in vitro and in vivo.

PubMed

Oliveira, R J; Mantovani, M S; Silva, A F da; Pesarini, J R; Mauro, M O; Ribeiro, L R

2014-04-01

The compounds 6-dimethylaminopurine and cycloheximide promote the successful production of cloned mammals and have been used in the development of embryos produced by somatic cell nuclear transfer. This study investigated the effects of 6-dimethylaminopurine and cycloheximide in vitro, using the thiazolyl blue tetrazolium bromide colorimetric assay to assess cytotoxicity, the trypan blue exclusion assay to assess cell viability, the comet assay to assess genotoxicity, and the micronucleus test with cytokinesis block to test mutagenicity. In addition, the comet assay and the micronucleus test were also performed on peripheral blood cells of 54 male Swiss mice, 35 g each, to assess the effects of the compounds in vivo. The results indicated that both 6-dimethylaminopurine and cycloheximide, at the concentrations and doses tested, were cytotoxic in vitro and genotoxic and mutagenic in vitro and in vivo, altered the nuclear division index in vitro, but did not diminish cell viability in vitro. Considering that alterations in DNA play important roles in mutagenesis, carcinogenesis, and morphofunctional teratogenesis and reduce embryonic viability, this study indicated that 6-dimethylaminopurine and cycloheximide utilized in the process of mammalian cloning may be responsible for the low embryo viability commonly seen in nuclear transfer after implantation in utero.

Application of micronucleus test and comet assay to evaluate BTEX biodegradation.

PubMed

Mazzeo, Dânia Elisa Christofoletti; Matsumoto, Silvia Tamie; Levy, Carlos Emílio; de Angelis, Dejanira de Franceschi; Marin-Morales, Maria Aparecida

2013-01-01

The BTEX (benzene, toluene, ethylbenzene and xylene) mixture is an environmental pollutant that has a high potential to contaminate water resources, especially groundwater. The bioremediation process by microorganisms has often been used as a tool for removing BTEX from contaminated sites. The application of biological assays is useful in evaluating the efficiency of bioremediation processes, besides identifying the toxicity of the original contaminants. It also allows identifying the effects of possible metabolites formed during the biodegradation process on test organisms. In this study, we evaluated the genotoxic and mutagenic potential of five different BTEX concentrations in rat hepatoma tissue culture (HTC) cells, using comet and micronucleus assays, before and after biodegradation. A mutagenic effect was observed for the highest concentration tested and for its respective non-biodegraded concentration. Genotoxicity was significant for all non-biodegraded concentrations and not significant for the biodegraded ones. According to our results, we can state that BTEX is mutagenic at concentrations close to its water solubility, and genotoxic even at lower concentrations, differing from some described results reported for the mixture components, when tested individually. Our results suggest a synergistic effect for the mixture and that the biodegradation process is a safe and efficient methodology to be applied at BTEX-contaminated sites. Copyright © 2012 Elsevier Ltd. All rights reserved.

Genotoxicity testing of two lead-compounds in somatic cells of Drosophila melanogaster.

PubMed

Carmona, Erico R; Creus, Amadeu; Marcos, Ricard

2011-09-18

The in vivo genotoxic activity of two inorganic lead compounds was studied in Drosophila melanogaster by measurement of two different genetic endpoints. We used the wing-spot test and the comet assay. The comet assay was conducted with larval haemocytes. The results from the wing-spot test showed that neither lead chloride, PbCl(2), nor lead nitrate, Pb(NO(3))(2), were able to induce significant increases in the frequency of mutant spots. In addition, the combined treatments with gamma-radiation and PbCl(2) or Pb(NO(3))(2) did not show significant variations in the frequency of the three categories of mutant spots recorded, compared with the frequency induced by gamma-radiation alone. This seems to indicate that the lead compounds tested do not interact with the repair of the genetic damage induced by ionizing radiation. When the lead compounds were evaluated in the in vivo comet assay with haemocytes, Pb(NO(3))(2) was effective in inducing significant increases of DNA damage with a direct dose-response pattern. These results confirm the usefulness of the comet assay with haemocytes as an in vivo model and support the assumption that there is a genotoxic risk associated with lead exposure. Copyright © 2011 Elsevier B.V. All rights reserved.

Evaluation of in vitro cytoxicity and genotoxicity of size-fractionated air particles sampled during road tunnel construction.

PubMed

Dominici, Luca; Guerrera, Elena; Villarini, Milena; Fatigoni, Cristina; Moretti, Massimo; Blasi, Paolo; Monarca, Silvano

2013-01-01

In tunnel construction, workers exposed to dust from blasting, gases, diesel exhausts, and oil mist have shown higher risk for pulmonary diseases. A clear mechanism to explain how these pollutants determine diseases is lacking, and alveolar epithelium's capacity to ingest inhaled fine particles is not well characterized. The objective of this study was to assess the genotoxic effect exerted by fine particles collected in seven tunnels using the cytokinesis-block micronuclei test in an in vitro model on type II lung epithelium A549 cells. For each tunnel, five fractions with different aerodynamic diameters of particulate matter were collected with a multistage cascade sampler. The human epithelial cell line A549 was exposed to 0.2 m(3)/mL equivalent of particulate for 24 h before testing. The cytotoxic effects of particulate matter on A549 cells were also evaluated in two different viability tests. In order to evaluate the cells' ability to take up fine particles, imaging with transmission electron microscopy of cells after exposure to particulate matter was performed. Particle endocytosis after 24 h exposure was observed as intracellular aggregates of membrane-bound particles. This morphologic evidence did not correspond to an increase in genotoxicity detected by the micronucleus test.

Evaluation of In Vitro Cytoxicity and Genotoxicity of Size-Fractionated Air Particles Sampled during Road Tunnel Construction

PubMed Central

Dominici, Luca; Guerrera, Elena; Villarini, Milena; Fatigoni, Cristina; Moretti, Massimo; Blasi, Paolo; Monarca, Silvano

2013-01-01

In tunnel construction, workers exposed to dust from blasting, gases, diesel exhausts, and oil mist have shown higher risk for pulmonary diseases. A clear mechanism to explain how these pollutants determine diseases is lacking, and alveolar epithelium's capacity to ingest inhaled fine particles is not well characterized. The objective of this study was to assess the genotoxic effect exerted by fine particles collected in seven tunnels using the cytokinesis-block micronuclei test in an in vitro model on type II lung epithelium A549 cells. For each tunnel, five fractions with different aerodynamic diameters of particulate matter were collected with a multistage cascade sampler. The human epithelial cell line A549 was exposed to 0.2 m3/mL equivalent of particulate for 24 h before testing. The cytotoxic effects of particulate matter on A549 cells were also evaluated in two different viability tests. In order to evaluate the cells' ability to take up fine particles, imaging with transmission electron microscopy of cells after exposure to particulate matter was performed. Particle endocytosis after 24 h exposure was observed as intracellular aggregates of membrane-bound particles. This morphologic evidence did not correspond to an increase in genotoxicity detected by the micronucleus test. PMID:24069598

Evaluation of genotoxic effects of lead in pottery-glaze workers using micronucleus assay, alkaline comet assay and DNA diffusion assay.

PubMed

Kašuba, V; Rozgaj, R; Milić, M; Zelježić, D; Kopjar, N; Pizent, A; Kljaković-Gašpić, Z; Jazbec, A

2012-10-01

We investigated genotoxic effects of occupational exposure to lead acetate in pottery-glaze ceramic workers. The study was carried out in 30 exposed workers and 30 matched controls, to whom several biochemical parameters-the blood lead (B-Pb; range: exposed, 41.68-404.77; controls, 12-52) and cadmium (B-Cd) level, the activity of delta-aminolevulinic acid dehydratase (ALAD), erythrocyte protoporphyrin (EP), the level of vitamin B(12) and folate in serum-were measured. The genotoxic effects were evaluated by the alkaline comet assay, the DNA diffusion assay and micronucleus test in peripheral blood lymphocytes. Subjects exposed to lead had significantly higher B-Pb level and, consequently, increased values of tail intensity (TI), frequency of apoptotic and necrotic cells, and frequency of micronuclei (MN). In contrast, their activity of ALAD, the level of vitamin B(12) and folate in serum were significantly lower compared to controls. Poisson regression analysis showed a significant correlation of profession, duration of exposure, smoking, level of cadmium in blood, ALAD and EP with primary DNA damage. A majority of primary damage repairs in a short period after exposure to a genotoxic agent. In addition, the influence of gender and level of vitamin B(12) and folate in serum MN frequency in exposed group was observed. In this study, DNA diffusion and micronucleus test showed higher influence of tested parameters to DNA damage. The results indicate a need for concomitant use of at least two different biomarkers of exposure when estimating a genetic risk of lead exposure.

Genetic Toxicology in the 21st Century: Reflections and Future Directions

PubMed Central

Mahadevan, Brinda; Snyder, Ronald D.; Waters, Michael D.; Benz, R. Daniel; Kemper, Raymond A.; Tice, Raymond R.; Richard, Ann M.

2011-01-01

A symposium at the 40th anniversary of the Environmental Mutagen Society, held from October 24–28, 2009 in St. Louis, MO, surveyed the current status and future directions of genetic toxicology. This article summarizes the presentations and provides a perspective on the future. An abbreviated history is presented, highlighting the current standard battery of genotoxicity assays and persistent challenges. Application of computational toxicology to safety testing within a regulatory setting is discussed as a means for reducing the need for animal testing and human clinical trials, and current approaches and applications of in silico genotoxicity screening approaches across the pharmaceutical industry were surveyed and are reported here. The expanded use of toxicogenomics to illuminate mechanisms and bridge genotoxicity and carcinogenicity, and new public efforts to use high-throughput screening technologies to address lack of toxicity evaluation for the backlog of thousands of industrial chemicals in the environment are detailed. The Tox21 project involves coordinated efforts of four U.S. Government regulatory/research entities to use new and innovative assays to characterize key steps in toxicity pathways, including genotoxic and nongenotoxic mechanisms for carcinogenesis. Progress to date, highlighting preliminary test results from the National Toxicology Program is summarized. Finally, an overview is presented of ToxCast™, a related research program of the U.S. Environmental Protection Agency, using a broad array of high throughput and high content technologies for toxicity profiling of environmental chemicals, and computational toxicology modeling. Progress and challenges, including the pressing need to incorporate metabolic activation capability, are summarized. PMID:21538556

Identification of genotoxic compounds using isogenic DNA repair deficient DT40 cell lines on a quantitative high throughput screening platform

PubMed Central

Nishihara, Kana; Huang, Ruili; Zhao, Jinghua; Shahane, Sampada A.; Witt, Kristine L.; Smith-Roe, Stephanie L.; Tice, Raymond R.; Takeda, Shunichi; Xia, Menghang

2016-01-01

DNA repair pathways play a critical role in maintaining cellular homeostasis by repairing DNA damage induced by endogenous processes and xenobiotics, including environmental chemicals. Induction of DNA damage may lead to genomic instability, disruption of cellular homeostasis and potentially tumours. Isogenic chicken DT40 B-lymphocyte cell lines deficient in DNA repair pathways can be used to identify genotoxic compounds and aid in characterising the nature of the induced DNA damage. As part of the US Tox21 program, we previously optimised several different DT40 isogenic clones on a high-throughput screening platform and confirmed the utility of this approach for detecting genotoxicants by measuring differential cytotoxicity in wild-type and DNA repair-deficient clones following chemical exposure. In the study reported here, we screened the Tox21 10K compound library against two isogenic DNA repair-deficient DT40 cell lines (KU70 −/−/RAD54 −/− and REV3 −/−) and the wild-type cell line using a cell viability assay that measures intracellular adenosine triphosphate levels. KU70 and RAD54 are genes associated with DNA double-strand break repair processes, and REV3 is associated with translesion DNA synthesis pathways. Active compounds identified in the primary screening included many well-known genotoxicants (e.g. adriamycin, melphalan) and several compounds previously untested for genotoxicity. A subset of compounds was further evaluated by assessing their ability to induce micronuclei and phosphorylated H2AX. Using this comprehensive approach, three compounds with previously undefined genotoxicity—2-oxiranemethanamine, AD-67 and tetraphenylolethane glycidyl ether—were identified as genotoxic. These results demonstrate the utility of this approach for identifying and prioritising compounds that may damage DNA. PMID:26243743

Antigenotoxic effect of acute, subacute and chronic treatments with Amazonian camu-camu (Myrciaria dubia) juice on mice blood cells.

PubMed

da Silva, Francisco Carlos; Arruda, Andrelisse; Ledel, Alexandre; Dauth, Cíntia; Romão, Nathalia Faria; Viana, Rafaele Nazário; de Barros Falcão Ferraz, Alexandre; Picada, Jaqueline Nascimento; Pereira, Patrícia

2012-07-01

Myrciaria dubia, a plant native to the Amazon region, stands out as a fruit rich in vitamin C and other metabolites with nutritional potential. We evaluated the antioxidant, genotoxic and antigenotoxic potential of M. dubia juice on blood cells of mice after acute, subacute and chronic treatments. Flavonoids and vitamin C present in the fruit of M. dubia were quantified. In vitro antioxidant activity was evaluated by DPPH assay. Blood samples were collected for analysis after treatment, and the alkaline comet assay was used to analyze the genotoxic and antigenotoxic activity (ex vivo analysis using H(2)O(2)). The amount of vitamin C per 100mL of M. dubia was 52.5mg. DPPH assay showed an antioxidant potential of the fruit. No M. dubia concentration tested exerted any genotoxic effect on mice blood cells. In the ex vivo test, the juice demonstrated antigenotoxic effect, and acute treatment produced the most significant results. After the treatments, there was no evidence of toxicity or death. In conclusion, our data show that M. dubia juice has antigenotoxic and antioxidant activities, though with no genotoxicity for blood cells. Nevertheless, more in-depth studies should be conducted to assess the safety of this fruit for human consumption. Copyright © 2012 Elsevier Ltd. All rights reserved.

Determination of the mutagenic and genotoxic potential of simulated leachate from an automobile workshop soil on eukaryotic system.

PubMed

Alabi, Okunola Adenrele; Omosebi, Omotoyosi; Chizea, Ifychukwwu

2015-07-01

Contamination of soil and water bodies with spent engine oil and petroleum products is a serious ecological problem, primarily in the automobile workshops and garages. This has potential short and chronic adverse health risks. Information is currently scarce on the potential mutagenicity and genotoxicity of such wastes. In this study, the potential mutagenic and genotoxic effects of simulated leachate from automobile workshop soil in Sagamu, Ogun state, Nigeria, were investigated. The assays utilized were bone marrow micronucleus (MN) and chromosome aberration (CA), sperm morphology and sperm count in mice. The physicochemical analysis of the leachate was also carried out. Experiments were carried out at concentrations of 1, 5, 10, 25, 50, 75 and 100% (volume per volume; leachate:distilled water) of the leachate sample. MN analysis showed a concentration-dependent induction of micronucleated polychromatic erythrocytes across the treatment groups. In the CA test, there was concentration-dependent significant reduction in mitotic index and induction of different types of CAs. Assessment of sperm shape showed a significant increase in sperm abnormalities with significant decrease in mean sperm count in treated groups. Heavy metals analyzed in the tested sample are believed to contribute significantly to the observed genetic damage. This indicates that automobile workshop soil-simulated leachate contains potential genotoxic agents and constitutes a genetic risk in exposed human population. © The Author(s) 2013.

Toxicological analysis and anti-inflammatory effects of essential oil from Piper vicosanum leaves.

PubMed

Hoff Brait, Débora Regina; Mattos Vaz, Márcia Soares; da Silva Arrigo, Jucicléia; Borges de Carvalho, Luciana Noia; Souza de Araújo, Flávio Henrique; Vani, Juliana Miron; da Silva Mota, Jonas; Cardoso, Claudia Andrea Lima; Oliveira, Rodrigo Juliano; Negrão, Fábio Juliano; Kassuya, Cândida Aparecida Leite; Arena, Arielle Cristina

2015-12-01

This study assessed the anti-inflammatory effects of the essential oil from Piper vicosanum leaves (OPV) and evaluated the toxicological potential of this oil through acute toxicity, genotoxicity and mutagenicity tests. The acute toxicity of OPV was evaluated following oral administration to female rats at a single dose of 2 g/kg b.w. To evaluate the genotoxic and mutagenic potential, male mice were divided into five groups: I: negative control; II: positive control; III: 500 mg/kg of OPV; IV: 1000 mg/kg of OPV; V: 2000 mg/kg of OPV. The anti-inflammatory activity of OPV was evaluated in carrageenan-induced pleurisy and paw edema models in rats. No signs of acute toxicity were observed, indicating that the LD50 of this oil is greater than 2000 mg/kg. In the comet assay, OPV did not increase the frequency or rate of DNA damage in groups treated with any of the doses assessed compared to that in the negative control group. In the micronucleus test, the animals treated did not exhibit any cytotoxic or genotoxic changes in peripheral blood erythrocytes. OPV (100 and 300 mg/kg) significantly reduced edema formation and inhibited leukocyte migration analyzed in the carrageenan-induced edema and pleurisy models. These results show that OPV has anti-inflammatory potential without causing acute toxicity or genotoxicity. Copyright © 2015 Elsevier Inc. All rights reserved.

Antimycobacterial, anti-inflammatory and genotoxicity evaluation of plants used for the treatment of tuberculosis and related symptoms in South Africa.

PubMed

Madikizela, B; Ndhlala, A R; Finnie, J F; Van Staden, J

2014-04-28

Emergence of drug-resistant tuberculosis strains and long duration of treatment has established an urgent need to search for new effective agents. The great floral diversity of South Africa has potential for producing new bioactive compounds, therefore pharmacological screening of plant extracts within this region offers much potential. To assess the in vitro antimycobacterial, anti-inflammatory and genotoxicity activity of selected plants that are used for the treatment of TB and related symptoms in South Africa. Ground plant materials from 10 plants were extracted sequentially with four solvents (petroleum ether, dichloromethane, 80% ethanol and water) and a total of 68 extracts were produced. A broth microdilution method was used to screen extracts against Mycobacterium tuberculosis H37Ra. The cyclooxygenase-2 (COX-2) enzyme was used to evaluate the anti-inflammatory activity of the extracts and the Salmonella microsome assay using two Salmonella typhimurium strains (TA98 and TA100) to establish genotoxicity. Six out of 68 extracts showed good antimycobacterial activity. Three extracts showed good inhibition (>70%) of COX-2 enzyme. All the extracts tested were non-genotoxic against the tested Salmonella strains. The results observed in this study indicate that some of the plants such as Abrus precatorius subsp. africanus, Ficus sur, Pentanisia prunelloides and Terminalia phanerophlebia could be investigated further against drug-resistant TB strains. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Comparative in vitro genotoxicity study of ZnO nanoparticles, ZnO macroparticles and ZnCl2 to MDCK kidney cells: Size matters.

PubMed

Kononenko, Veno; Repar, Neža; Marušič, Nika; Drašler, Barbara; Romih, Tea; Hočevar, Samo; Drobne, Damjana

2017-04-01

In the present study, we evaluated the roles that ZnO particle size and Zn ion release have on cyto- and genotoxicity in vitro. The Madin-Darby canine kidney (MDCK) cells were treated with ZnO nanoparticles (NPs), ZnO macroparticles (MPs), and ZnCl 2 as a source of free Zn ions. We first tested cytotoxicity to define sub-cytotoxic exposure concentrations and afterwards we performed alkaline comet and cytokinesis-block micronucleus assays. Additionally, the activities of both catalase (CAT) and glutathione S-transferase (GST) were evaluated in order to examine the potential impairment of cellular stress-defence capacity. The amount of dissolved Zn ions from ZnO NPs in the cell culture medium was evaluated by an optimized voltammetric method. The results showed that all the tested zinc compounds induced similar concentration-dependent cytotoxicity, but only ZnO NPs significantly elevated DNA and chromosomal damage, which was accompanied by a reduction of GST and CAT activity. Although Zn ion release from ZnO NPs in cell culture medium was significant, our results show that this reason alone cannot explain the ZnO genotoxicity seen in this experiment. We discuss that genotoxicity of ZnO NPs depends on the particle size, which determines the physical principles of their dissolution and cellular internalisation. Copyright © 2017 Elsevier Ltd. All rights reserved.

Genotoxicity testing of a fenugreek extract.

PubMed

Flammang, A M; Cifone, M A; Erexson, G L; Stankowski, L F

2004-11-01

Fenugreek seeds have been used in traditional medicines as a remedy for diabetes. Rich in protein, fenugreek seeds contain the unique major free amino acid 4-hydroxyisoleucine (4-OH-Ile), which has been characterized as one of the active ingredients for blood glucose control. Current use of fenugreek in foodstuff has been limited to its role as a flavoring agent, and not as an ingredient to help mitigate the blood glucose response for people with diabetes. As part of a safety evaluation of novel ingredients for use in blood glucose control, the potential genotoxicity of a fenugreek seed extract (THL), containing a minimum of 40% 4-OH-ILE, was evaluated using the standard battery of tests (reverse mutation assay; mouse lymphoma forward mutation assay; mouse micronucleus assay) recommended by US Food and Drug Administration (FDA) for food ingredients. THL was determined not to be genotoxic under the conditions of the tested genetic toxicity battery. The negative assay results provide support that addition of THL to foodstuffs formulated for people with diabetes is expected to be safe. A wide safety margin is established, as anticipated doses are small compared to the doses administered in the assays.

Genotoxic potential of organic extracts from particle emissions of diesel and rapeseed oil powered engines.

PubMed

Topinka, Jan; Milcova, Alena; Schmuczerova, Jana; Mazac, Martin; Pechout, Martin; Vojtisek-Lom, Michal

2012-07-07

The present study was performed to identify possible genotoxicity induced by organic extracts from particulate matter in the exhaust of two typical diesel engines run on diesel fuel and neat heated fuel-grade rapeseed oil: a Cummins ISBe4 engine tested using the World Harmonized Steady State Test Cycle (WHSC) and modified Engine Steady Cycle (ESC) and a Zetor 1505 engine tested using the Non-Road Steady State Cycle (NRSC). In addition, biodiesel B-100 (neat methylester of rapeseed oil) was tested in the Cummins engine run on the modified ESC. Diluted exhaust was sampled with high-volume samplers on Teflon coated filters. Filters were extracted with dichlormethane (DCM) and DNA adduct levels induced by extractable organic matter (EOM) in an acellular assay of calf thymus DNA coupled with (32)P-postlabeling in the presence and absence of rat liver microsomal S9 fraction were employed. Simultaneously, the chemical analysis of 12 priority PAHs in EOM, including 7 carcinogenic PAHs (c-PAHs) was performed. The results suggest that diesel emissions contain substantially more total PAHs than rapeseed oil emissions (for the ESC) or that these concentrations were comparable (for the WHSC and NRSC), while c-PAHs levels were comparable (for the ESC) or significantly higher (for the WHSC and NRSC) for rapeseed oil emissions. DNA adduct levels induced by diesel and rapeseed oil derived EOM were comparable, but consistently slightly higher for diesel than for rapeseed oil. Highly significant correlations were found between 12 priority PAHs concentrations and DNA adduct levels (0.980; p<0.001) and these correlations were even stronger for c-PAHs (0.990; p<0.001). Metabolic activation by the microsomal S9 fraction resulted in several fold higher genotoxicity, suggesting a major contribution of PAHs to genotoxicity. Directly acting compounds, other than c-PAHs, and not requiring S9 to exhibit DNA reactivity were also significant. Generally, DNA adduct levels were more dependent on the type of engine and the test cycle than on the fuel. Our findings suggest that the genotoxicity of particulate emissions from the combustion of rapeseed oil is significant and is comparable to that from the combustion of diesel fuel. A more detailed study is ongoing to verify and extent these preliminary findings. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Determination of genetic toxicity and potential carcinogenicity in vitro--challenges post the Seventh Amendment to the European Cosmetics Directive.

PubMed

Tweats, D J; Scott, A D; Westmoreland, C; Carmichael, P L

2007-01-01

Genetic toxicology and its role in the detection of carcinogens is currently undergoing a period of reappraisal. There is an increasing interest in developing alternatives to animal testing and the three R's of reduction, refinement and replacement are the basis for EU and national animal protection laws the Seventh Amendment to the EU Cosmetics Directive will ban the marketing of cosmetic/personal care products that contain ingredients that have been tested in animal models. Thus in vivo tests such as the bone marrow micronucleus test, which has a key role in current testing strategies for genotoxicity, will not be available for this class of products. The attrition rate for new, valuable and safe chemicals tested in an in vitro-only testing battery, using the in vitro tests currently established for genotoxicity screening, will greatly increase once this legislation is in place. In addition there has been an explosion of knowledge concerning the cellular and molecular events leading to carcinogenesis. This knowledge has not yet been fully factored into screening chemicals for properties that are not directly linked to mutation induction. Thus there is a pressing need for new, more accurate approaches to determine genotoxicity and carcinogenicity. However, a considerable challenge is presented for these new approaches to be universally accepted and new tests sufficiently validated by March 2009 when the animal testing and marketing bans associated with the Seventh Amendment are due to come into force. This commentary brings together ideas and approaches from several international workshops and meetings to consider these issues.

Absence of genotoxic effects of the chalcone (E)-1-(2-hydroxyphenyl)-3-(4-methylphenyl)-prop-2-en-1-one) and its potential chemoprevention against DNA damage using in vitro and in vivo assays

PubMed Central

2017-01-01

The chalcone (E)-1-(2-hydroxyphenyl)-3-(4-methylphenyl)-prop-2-en-1-one), or 2HMC, displays antileishmanial, antimalarial, and antioxidant activities. The aim of this study was to investigate the cytotoxic, genotoxic, mutagenic, and protective effects of 2HMC using the Ames mutagenicity test, the mouse bone marrow micronucleus test, and the comet assay in mice. In the assessment using the Ames test, 2HMC did not increase the number of His+ revertants in Salmonella typhimurium strains, demonstrating lack of mutagenicity. 2HMC showed no significant increase in micronucleated polychromatic erythrocyte frequency (MNPCE) in the micronucleus test, or in DNA strand breaks using the comet assay, evidencing absence of genotoxicity. Regarding cytotoxicity, 2HMC exhibited moderate cytotoxicity in mouse bone marrow cells by micronucleus test. 2HMC showed antimutagenic action in co-administration with the positive controls, sodium azide (SA) and 4-nitroquinoline-1-oxide (4NQO), in the Ames test. Co-administered and mainly pre-administered with cyclophosphamide (CPA), 2HMC caused a decrease in the frequency of MNPCE using the micronucleus test and in DNA strand breaks using the comet assay. Thus, 2HMC exhibited antimutagenic and antigenotoxic effects, displaying a DNA-protective effect against CPA, SA, and 4NQO carcinogens. In conclusion, 2HMC presented antimutagenic, antigenotoxic and moderate cytotoxic effects; therefore it is a promising molecule for cancer prevention. PMID:28207781

Absence of genotoxic effects of the chalcone (E)-1-(2-hydroxyphenyl)-3-(4-methylphenyl)-prop-2-en-1-one) and its potential chemoprevention against DNA damage using in vitro and in vivo assays.

PubMed

Lima, Débora Cristina da Silva; Vale, Camila Regina do; Véras, Jefferson Hollanda; Bernardes, Aline; Pérez, Caridad Noda; Chen-Chen, Lee

2017-01-01

The chalcone (E)-1-(2-hydroxyphenyl)-3-(4-methylphenyl)-prop-2-en-1-one), or 2HMC, displays antileishmanial, antimalarial, and antioxidant activities. The aim of this study was to investigate the cytotoxic, genotoxic, mutagenic, and protective effects of 2HMC using the Ames mutagenicity test, the mouse bone marrow micronucleus test, and the comet assay in mice. In the assessment using the Ames test, 2HMC did not increase the number of His+ revertants in Salmonella typhimurium strains, demonstrating lack of mutagenicity. 2HMC showed no significant increase in micronucleated polychromatic erythrocyte frequency (MNPCE) in the micronucleus test, or in DNA strand breaks using the comet assay, evidencing absence of genotoxicity. Regarding cytotoxicity, 2HMC exhibited moderate cytotoxicity in mouse bone marrow cells by micronucleus test. 2HMC showed antimutagenic action in co-administration with the positive controls, sodium azide (SA) and 4-nitroquinoline-1-oxide (4NQO), in the Ames test. Co-administered and mainly pre-administered with cyclophosphamide (CPA), 2HMC caused a decrease in the frequency of MNPCE using the micronucleus test and in DNA strand breaks using the comet assay. Thus, 2HMC exhibited antimutagenic and antigenotoxic effects, displaying a DNA-protective effect against CPA, SA, and 4NQO carcinogens. In conclusion, 2HMC presented antimutagenic, antigenotoxic and moderate cytotoxic effects; therefore it is a promising molecule for cancer prevention.

Mutagenicity and genotoxicity studies of aspartame.

PubMed

Otabe, Akira; Ohta, Fumio; Takumi, Asuka; Lynch, Barry

2018-02-08

Two studies were conducted to further assess its mutagenic and genotoxic potential. In a bacterial reverse mutation pre-incubation study, Salmonella typhimurium strains TA100, TA1535, TA98, and TA1537 and Escherichia coli WP2 uvrA were treated with aspartame at concentrations of up to 5000 μg/plate with or without metabolic activation and showed no mutagenic potential. Similarly, in vivo micronucleus testing of aspartame following gavage administration (500-2000 mg/kg body weight) to Crlj:CD1(ICR) strain SPF male mice showed no increase in the proportion of micronucleated polychromatic erythrocytes in bone marrow cells collected and evaluated 24 or 48 h post administration. Overall, aspartame had no potential for mutagenic or genotoxic activity. Copyright © 2018 Elsevier Inc. All rights reserved.

In vitro genotoxicity and cytotoxicity of polydopamine-coated magnetic nanostructures.

PubMed

Woźniak, Anna; Walawender, Magdalena; Tempka, Dominika; Coy, Emerson; Załęski, Karol; Grześkowiak, Bartosz F; Mrówczyński, Radosław

2017-10-01

Synthesis of magnetic nanoparticles and magnetic nanoclusters was performed by the co-precipitation method or solvothermal synthesis, respectively, followed by oxidative polymerization of dopamine, resulting in a polydopamine (PDA) shell. The nanomaterials obtained were described using TEM, FTIR and magnetic measurements. For the first time, cyto- and genotoxicity studies of polydopamine-coated nanostructures were performed on cancer and normal cell lines, providing in-depth insight into the toxicity of such materials. The tests conducted, e.g. ROS, apoptosis and DNA double-break of the nanomaterials obtained revealed the low toxicity of these structures. Thus, these results prove the biocompatibility and low genotoxicity of these materials and provide new data on the toxicity of PDA-coated materials, which is of great importance for their biomedical application. Copyright © 2017 Elsevier Ltd. All rights reserved.

Genotoxicity evaluation of the naturally-derived food colorant, gardenia blue, and its precursor, genipin.

PubMed

Hobbs, Cheryl A; Koyanagi, Mihoko; Swartz, Carol; Davis, Jeffrey; Maronpot, Robert; Recio, Leslie; Hayashi, Shim-Mo

2018-06-04

Gardenia blue is widely used in Eastern Asia as a natural food colorant. To evaluate the genotoxic potential of gardenia blue, as well as genipin, the natural starting material from which it is produced, a GLP-compliant test battery was conducted according to OECD guidelines. No evidence of mutagenicity of gardenia blue was detected in a 5-strain bacterial reverse mutation assay, with or without metabolic activation; an equivocal response for genipin occurred in S. typhimurium TA97a without metabolic activation. In in vitro micronucleus and chromosome aberration assays, genipin tested positive under some test conditions; however, gardenia blue tested negative in both assays. In combined micronucleus/comet assays conducted in male and female B6C3F1 mice, exposure to genipin at doses reaching maximal toxicity (74 and 222 mg/kg bw/day for males and females, respectively) or gardenia blue tested up to the limit dose (2000 mg/kg bw/day) did not induce micronuclei in peripheral blood or DNA damage in several examined tissues. Modified ("reverse") comet assays showed no evidence of DNA crosslinking potential of either genipin, known to form crosslinks with other macromolecules, or gardenia blue. Our results indicate that consumption of gardenia blue in food products does not pose a significant genotoxic concern for humans. Copyright © 2018. Published by Elsevier Ltd.

Characterization and safety evaluation of a Deinococcus member as feed additive for hens.

PubMed

Wu, Szu-Yin; Li, I-Chen; Lin, Yi-Chin; Chen, Chin-Chu

2016-04-01

As previous studies mainly focus on understanding the mechanisms of radioresistance in Deinococcus bacteria, the present study aimed at characterizing and verifying the safety use of the GKB-Aid 1995 strain, a member of the radiation-resistant bacterial genus Deinococcus, as an ingredient in feed supplements. Using Vitek 2 system and 16S rRNA gene sequencing, GKB-Aid 1995 most resembles Deinococcus grandis. The Ames test, in vitro chromosomal test, in vivo micronucleus test and acute toxicity test were performed subsequently for its safety evaluation. As there is a possibility that the pigment of GKB-Aid 1995 can pass from feed to eggs intended for human consumption, an acute toxicity test was also carried out in pigmented egg yolk. The results confirmed that GKB-Aid 1995 was non-genotoxic in three genotoxicity experiments, and the LD50 of GKB-Aid 1995 and the pigmented egg yolk in ICR mice was greater than 10 and 12 g kg(-1) body weight, respectively. Overall, these data indicate that GKB-Aid 1995 is a non-toxic substance with no genotoxicity and is therefore safe to be used as a feed supplement or feed additive. This study suggests there is potential in developing GKB-Aid 1995 as an animal feed additive intended to enhance yolk coloration to meet the demand of consumers. Copyright © 2016 Elsevier Inc. All rights reserved.

Toxicity evaluation of the photoprotective compound LQFM048: Eye irritation, skin toxicity and genotoxic endpoints.

PubMed

de Ávila, Renato Ivan; de Sousa Vieira, Marcelo; Gaeti, Marilisa Pedroso Nogueira; Moreira, Larissa Cleres; de Brito Rodrigues, Laís; de Oliveira, Gisele Augusto Rodrigues; Batista, Aline Carvalho; Vinhal, Daniela Cristina; Menegatti, Ricardo; Valadares, Marize Campos

2017-02-01

A new molecule, LQFM048, originally designed through molecular hybridization using green chemistry approach, is in development as a photoprotective agent. Eye irritation, skin toxicity and genotoxicity evaluations are mandatory for predicting health risks. In this context, the purpose of this study was to investigate the eye irritation potential of LQFM048 by combining Short Time Exposure (STE), Bovine Corneal Opacity and Permeability (BCOP) associated with corneal histomorphometry and Hen's Egg Test-Chorioallantoic Membrane (HET-CAM). Additionally, skin toxicity was evaluated by interleukin-18 production in the HaCaT keratinocyte, Local Lymph Node Assay (LLNA:BrdU-ELISA) method, 3T3 Neutral red uptake (NRU) assay and in vivo phototoxicity test. Genotoxic potential of LQFM048 was also analyzed by cytokinesis-block micronucleus assay (MNvit test-cytoB) in HepG2 cells. Our results showed that LQFM048 did not induce eye irritation and it was classified as UN GHS No Category for both STE and BCOP assays and non-irritating for HET-CAM test. LQFM048 showed non-potential skin sensitization with stimulation index (SI=0.7) in the LLNA:BrdU-ELISA method. Corroborating in vivo tests, it did not promote significant cytotoxicity in HaCaT cells and it showed similar levels of IL-18 when compared to control. Furthermore, LQFM048 induced non-phototoxic potential with photo-irritation factor (PIF) and mean photo effect (MPE) of 1 and -0.138, respectively, for 3T3 cells. Similarly, it was not phototoxic for in vivo testing with or without exposure to UVA, showing SI values of 1 and 1.2, respectively. The micronucleus test showed that LQFM048 was not genotoxic, under the conditions tested.In conclusion, LQFM048, a heterocyclic compound obtained through an environmentally acceptable simple synthetic route, seems to be safe for human use, especially for the development of a new sunscreen product, since it is neither an eye irritant, nor a contact allergen, nor mutagenic and nor phototoxic. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Nongenotoxic effects and a reduction of the DXR-induced genotoxic effects of Helianthus annuus Linné (sunflower) seeds revealed by micronucleus assays in mouse bone marrow.

PubMed

Boriollo, Marcelo Fabiano Gomes; Souza, Luiz Silva; Resende, Marielly Reis; Silva, Thaísla Andrielle da; Oliveira, Nelma de Mello Silva; Resck, Maria Cristina Costa; Dias, Carlos Tadeu dos Santos; Fiorini, João Evangelista

2014-04-02

This research evaluated the genotoxicity of oil and tincture of H. annuus L. seeds using the micronucleus assay in bone marrow of mice. The interaction between these preparations and the genotoxic effects of doxorubicin (DXR) was also analysed (antigenotoxicity test). Experimental groups were evaluated at 24-48 h post treatment with N-Nitroso-N-ethylurea (positive control - NEU), DXR (chemotherapeutic), NaCl (negative control), a sunflower tincture (THALS) and two sources of sunflower oils (POHALS and FOHALS). Antigenotoxic assays were carried out using the sunflower tincture and oils separately and in combination with NUE or DXR. For THALS, analysis of the MNPCEs showed no significant differences between treatment doses (250-2,000 mg.Kg-1) and NaCl. A significant reduction in MNPCE was observed when THALS (2,000 mg.Kg-1) was administered in combination with DXR (5 mg.Kg-1). For POHALS or FOHALS, analysis of the MNPCEs also showed no significant differences between treatment doses (250-2,000 mg.Kg-1) and NaCl. However, the combination DXR + POHALS (2,000 mg.Kg-1) or DXR + FOHALS (2,000 mg.Kg-1) not contributed to the MNPCEs reduction. This research suggests absence of genotoxicity of THALS, dose-, time- and sex-independent, and its combination with DXR can reduce the genotoxic effects of DXR. POHALS and FOHALS also showed absence of genotoxicity, but their association with DXR showed no antigenotoxic effects.

Nongenotoxic effects and a reduction of the DXR-induced genotoxic effects of Helianthus annuus Linné (sunflower) seeds revealed by micronucleus assays in mouse bone marrow

PubMed Central

2014-01-01

Background This research evaluated the genotoxicity of oil and tincture of H. annuus L. seeds using the micronucleus assay in bone marrow of mice. The interaction between these preparations and the genotoxic effects of doxorubicin (DXR) was also analysed (antigenotoxicity test). Methods Experimental groups were evaluated at 24-48 h post treatment with N-Nitroso-N-ethylurea (positive control – NEU), DXR (chemotherapeutic), NaCl (negative control), a sunflower tincture (THALS) and two sources of sunflower oils (POHALS and FOHALS). Antigenotoxic assays were carried out using the sunflower tincture and oils separately and in combination with NUE or DXR. Results For THALS, analysis of the MNPCEs showed no significant differences between treatment doses (250–2,000 mg.Kg-1) and NaCl. A significant reduction in MNPCE was observed when THALS (2,000 mg.Kg-1) was administered in combination with DXR (5 mg.Kg-1). For POHALS or FOHALS, analysis of the MNPCEs also showed no significant differences between treatment doses (250–2,000 mg.Kg-1) and NaCl. However, the combination DXR + POHALS (2,000 mg.Kg-1) or DXR + FOHALS (2,000 mg.Kg-1) not contributed to the MNPCEs reduction. Conclusions This research suggests absence of genotoxicity of THALS, dose-, time- and sex-independent, and its combination with DXR can reduce the genotoxic effects of DXR. POHALS and FOHALS also showed absence of genotoxicity, but their association with DXR showed no antigenotoxic effects. PMID:24694203

Conventional and whitening toothpastes: cytotoxicity, genotoxicity and effect on the enamel surface.

PubMed

Camargo, Samira Esteves Afonso; Jóias, Renata Pilli; Santana-Melo, Gabriela Fátima; Ferreira, Lara Tolentino; El Achkar, Vivian Narana Ribeiro; Rode, Sigmar de Mello

2014-12-01

To evaluate the cytotoxicity and genotoxicity of whitening and common toothpastes, and the surface roughness of tooth enamel submitted to brushing with both toothpastes. Samples of whitening toothpastes [Colgate Whitening (CW) and Oral-B Whitening (OBW)] and regular (non-whitening) toothpastes (Colgate and Oral-B) were extracted in culture medium. Gingival human fibroblasts (FMM-1) were placed in contact with different dilutions of culture media that had been previously exposed to such materials, and the cytotoxicity was evaluated using the MTT assay. The genotoxicity was assessed by the micronucleus formation assay in Chinese hamster fibroblasts (V79). The cell survival rate and micronuclei number were assessed before and after exposure to the toothpaste extracts. For the surface roughness evaluation, 20 bovine tooth specimens, divided into four groups according to toothpastes, were submitted to 10,000 brushing cycles. The results were analyzed using the Mann-Whitney U and two-way ANOVA tests (P < 0.05). MTT assay showed that Colgate was significantly less cytotoxic than CW, Oral-B and OBW at all dilutions (P < 0.01). CW was the most cytotoxic toothpaste (P < 0.01). The whitening toothpastes showed the highest numbers of micronuclei compared to the untreated control (UC) (P < 0.01). Colgate and Oral-B toothpastes were not genotoxic compared to UC (P = 0.326). The OBW toothpaste was statistically significantly abrasive to the enamel surface (P < 0.01). The whitening toothpastes and Oral-B were cytotoxic to the cells. The whitening toothpastes were more genotoxic to cells in vitro than the common toothpastes, and genotoxicity was more pronounced in the OBW toothpaste.

Oxcarbazepine-induced cytotoxicity and genotoxicity in human lymphocyte cultures with or without metabolic activation.

PubMed

Atlı Şekeroğlu, Zülal; Kefelioğlu, Haluk; Kontaş Yedier, Seval; Şekeroğlu, Vedat; Delmecioğlu, Berrin

2017-03-01

There has been considerable debate about the relationship between epilepsy and cancer. Oxcarbazepine (OXC) is used for treating certain types of seizures in patients with epilepsy. There have been no detailed investigations about genotoxicity of OXC and its metabolites. Therefore, the aim of this study is to investigate the cytotoxic and genotoxic effects of OXC and its metabolites on cultured human lymphocytes. The cytotoxicity and genotoxicity of OXC on human peripheral blood lymphocytes were examined in vitro by sister chromatid exchange (SCE), chromosomal aberration (CA) and micronucleus (MN) tests. Cultures were treated with 125, 250 and 500 μg/ml of OXC in the presence (3 h treatment) and absence (24 h and 48 h treatment) of a metabolic activator (S9 mix). Dimethyl sulfoxide (DMSO) was used as a solvent control. OXC showed cytotoxic activities due to significant decreases in mitotic index (MI), proliferation index (PI) and nuclear division index (NDI) in the absence of S9 mix when compared with solvent control. Metabolites of OXC also significantly reduced MI and PI in cultures with S9 mix. OXC significantly increased the CAs, aberrant cells, SCE and MN values in the presence and absence of S9 mix. Our results indicated that both OXC and its metabolites have cytotoxic, cytostatic and genotoxic potential on human peripheral blood lymphocyte cultures under the experimental conditions. Further studies are necessary to elucidate the relationship between cytotoxic, cytostatic and genotoxic effects, and to make a possible risk assessment in patients receiving therapy with this drug.

Role of Zucchini and Its Distinctive Components in the Modulation of Degenerative Processes: Genotoxicity, Anti-Genotoxicity, Cytotoxicity and Apoptotic Effects

PubMed Central

Martínez-Valdivieso, Damián; Font, Rafael; Fernández-Bedmar, Zahira; Merinas-Amo, Tania; Gómez, Pedro; Alonso-Moraga, Ángeles

2017-01-01

Zucchini (Cucurbita pepo subsp. pepo) is a seasonal vegetable with high nutritional and medical values. Many useful properties of this fruit are attributed to bioactive compounds. Zucchini fruits (“Yellow” and “Light Green” varieties) and four distinctive components (lutein, β-carotene, zeaxanthin and dehydroascorbic acid) were selected. Firstly, the lutein, β-carotene, zeaxanthin and dehydroascorbic acid contents were determined in these fruits. Then, in order to evaluate the safety and suitability of their use, different assays were carried out: (i) genotoxicity and anti-genotoxicity tests to determine the safety and DNA-protection against hydrogen peroxide; (ii) cytotoxicity; and (iii) DNA fragmentation and Annexin V/PI (Propidium Iodide) assays to evaluate the pro-apoptotic effect. Results showed that: (i) all the substances were non-genotoxic; (ii) all the substances were anti-genotoxic except the highest concentration of lutein; (iii) “Yellow” zucchini epicarp and mesocarp exhibited the highest cytotoxic activity (IC50 > 0.1 mg/mL and 0.2 mg/mL, respectively); and (iv) “Light Green” zucchini skin induced internucleosomal DNA fragmentation, β-carotene being the possible molecule responsible for its pro-apoptotic activity. To sum up, zucchini fruit could play a positive role in human health and nutrition due to this fruit and its components were safe, able to inhibit significantly the H2O2-induced damage and exhibit anti-proliferative and pro-apoptotic activities toward HL60 (human promyelocytic leukemia cells) tumor cells. The information generated from this research should be considered when selecting potential accessions for breeding program purposes. PMID:28708122

Role of Zucchini and Its Distinctive Components in the Modulation of Degenerative Processes: Genotoxicity, Anti-Genotoxicity, Cytotoxicity and Apoptotic Effects.

PubMed

Martínez-Valdivieso, Damián; Font, Rafael; Fernández-Bedmar, Zahira; Merinas-Amo, Tania; Gómez, Pedro; Alonso-Moraga, Ángeles; Del Río-Celestino, Mercedes

2017-07-14

Zucchini ( Cucurbita pepo subsp. pepo ) is a seasonal vegetable with high nutritional and medical values. Many useful properties of this fruit are attributed to bioactive compounds. Zucchini fruits ("Yellow" and "Light Green" varieties) and four distinctive components (lutein, β-carotene, zeaxanthin and dehydroascorbic acid) were selected. Firstly, the lutein, β-carotene, zeaxanthin and dehydroascorbic acid contents were determined in these fruits. Then, in order to evaluate the safety and suitability of their use, different assays were carried out: (i) genotoxicity and anti-genotoxicity tests to determine the safety and DNA-protection against hydrogen peroxide; (ii) cytotoxicity; and (iii) DNA fragmentation and Annexin V/PI (Propidium Iodide) assays to evaluate the pro-apoptotic effect. Results showed that: (i) all the substances were non-genotoxic; (ii) all the substances were anti-genotoxic except the highest concentration of lutein; (iii) "Yellow" zucchini epicarp and mesocarp exhibited the highest cytotoxic activity (IC 50 > 0.1 mg/mL and 0.2 mg/mL, respectively); and (iv) "Light Green" zucchini skin induced internucleosomal DNA fragmentation, β-carotene being the possible molecule responsible for its pro-apoptotic activity. To sum up, zucchini fruit could play a positive role in human health and nutrition due to this fruit and its components were safe, able to inhibit significantly the H₂O₂-induced damage and exhibit anti-proliferative and pro-apoptotic activities toward HL60 (human promyelocytic leukemia cells) tumor cells. The information generated from this research should be considered when selecting potential accessions for breeding program purposes.

Structure-activity relationship of new antimalarial 1-aryl-3-susbtituted propanol derivatives: Synthesis, preliminary toxicity profiling, parasite life cycle stage studies, target exploration, and targeted delivery.

PubMed

Quiliano, Miguel; Pabón, Adriana; Moles, Ernest; Bonilla-Ramirez, Leonardo; Fabing, Isabelle; Fong, Kim Y; Nieto-Aco, Diego A; Wright, David W; Pizarro, Juan C; Vettorazzi, Ariane; López de Cerain, Adela; Deharo, Eric; Fernández-Busquets, Xavier; Garavito, Giovanny; Aldana, Ignacio; Galiano, Silvia

2018-05-25

Design, synthesis, structure-activity relationship, cytotoxicity studies, in silico drug-likeness, genotoxicity screening, and in vivo studies of new 1-aryl-3-substituted propanol derivatives led to the identification of nine compounds with promising in vitro (55, 56, 61, 64, 66, and 70-73) and in vivo (66 and 72) antimalarial profiles against Plasmodium falciparum and Plasmodium berghei. Compounds 55, 56, 61, 64, 66 and 70-73 exhibited potent antiplasmodial activity against chloroquine-resistant strain FCR-3 (IC 50 s < 0.28 μM), and compounds 55, 56, 64, 70, 71, and 72 showed potent biological activity in chloroquine-sensitive and multidrug-resistant strains (IC 50 s < 0.7 μM for 3D7, D6, FCR-3 and C235). All of these compounds share appropriate drug-likeness profiles and adequate selectivity indexes (77 < SI < 184) as well as lack genotoxicity. In vivo efficacy tests in a mouse model showed compounds 66 and 72 to be promising candidates as they exhibited significant parasitemia reductions of 96.4% and 80.4%, respectively. Additional studies such as liver stage and sporogony inhibition, target exploration of heat shock protein 90 of P. falciparum, targeted delivery by immunoliposomes, and enantiomer characterization were performed and strongly reinforce the hypothesis of 1-aryl-3-substituted propanol derivatives as promising antimalarial compounds. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

Three-dimensional transgenic cell model to quantify genotoxic effects of space environment

NASA Astrophysics Data System (ADS)

Gonda, S. R.; Wu, H.; Pingerelli, P. L.; Glickman, B. W.

In this paper we describe a three-dimensional, multicellular tissue-equivalent model, produced in NASA-designed, rotating wall bioreactors using mammalian cells engineered for genomic containment of multiple copies of defined target genes for genotoxic assessment. Rat 2λ fibroblasts, genetically engineered to contain high-density target genes for mutagenesis (Stratagene, Inc., Austin, TX), were cocultured with human epithelial cells on Cytodex beads in the High Aspect Ratio Bioreactor (Synthecon, Inc, Houston, TX). Multi-bead aggregates were formed by day 5 following the complete covering of the beads by fibroblasts. Cellular retraction occurred 8-14 days after coculture initiation culminating in spheroids retaining few or no beads. Analysis of the resulting tissue assemblies revealed: multicellular spheroids, fibroblasts synthesized collagen, and cell viability was retained for the 30-day test period after removal from the bioreactor. Quantification of mutation at the LacI gene in Rat 2λ fibroblasts in spheroids exposed to 0-2 Gy neon using the Big Blue color assay (Stratagene, Inc.), revealed a linear dose-response for mutation induction. Limited sequencing analysis of mutant clones from 0.25 or 1 Gy exposures revealed a higher frequency of deletions and multiple base sequencing changes with increasing dose. These results suggest that the three-dimensional, multicellular tissue assembly model produced in NASA bioreactors are applicable to a wide variety of studies involving the quantification and identification of genotocity including measurement of the inherent damage incurred in Space.

Comparative cytotoxicity and genotoxicity of cobalt (II, III) oxide, iron (III) oxide, silicon dioxide, and aluminum oxide nanoparticles on human lymphocytes in vitro.

PubMed

Rajiv, S; Jerobin, J; Saranya, V; Nainawat, M; Sharma, A; Makwana, P; Gayathri, C; Bharath, L; Singh, M; Kumar, M; Mukherjee, A; Chandrasekaran, N

2016-02-01

Despite the extensive use of nanoparticles (NPs) in various fields, adequate knowledge of human health risk and potential toxicity is still lacking. The human lymphocytes play a major role in the immune system, and it can alter the antioxidant level when exposed to NPs. Identification of the hazardous NPs was done using in vitro toxicity tests and this study mainly focuses on the comparative in vitro cytotoxicity and genotoxicity of four different NPs including cobalt (II, III) oxide (Co3O4), iron (III) oxide (Fe2O3), silicon dioxide (SiO2), and aluminum oxide (Al2O3) on human lymphocytes. The Co3O4 NPs showed decrease in cellular viability and increase in cell membrane damage followed by Fe2O3, SiO2, and Al2O3 NPs in a dose-dependent manner after 24 h of exposure to human lymphocytes. The oxidative stress was evidenced in human lymphocytes by the induction of reactive oxygen species, lipid peroxidation, and depletion of catalase, reduced glutathione, and superoxide dismutase. The Al2O3 NPs showed the least DNA damage when compared with all the other NPs. Chromosomal aberration was observed at 100 µg/ml when exposed to Co3O4 NPs and Fe2O3 NPs. The alteration in the level of antioxidant caused DNA damage and chromosomal aberration in human lymphocytes. © The Author(s) 2015.

Genotoxicity of endosseous implants using two cellular lineages in vitro.

PubMed

Matsumoto, Mariza; Filho, Hugo Nary; Ferrari, Raquel; Fernandes, Kristianne; Renno, Ana Claudia; Ribeiro, Daniel

2014-02-01

The genotoxic potential of corrosion eluates obtained from a single dental implant using murine fibroblasts or osteoblasts cells in vitro by the single-cell gel (comet) assay was examined. A single commercially available dental implant (Biotechnology) was eluted in a solution consisting of equal amounts of acetic acid and sodium chloride (0.1 M) for 1, 3, 7, 14, and 21 days. Murine fibroblast or osteoblast cultures were then exposed to all corrosion eluates obtained from endosseous dental implants for 30 minutes at 37°C. The results suggest that none of the eluates produced genotoxic changes in murine fibroblasts regardless of the length of exposure to the eluate. Similarly, no genotoxicity was found in osteoblasts. The results suggest that the dental implant eluates tested in this study did not induce genetic damage as depicted by the single-cell gel (comet) assay. Because DNA damage is an important event during oncogenesis, this study represents a relevant contribution to estimate the real risks to the cellular system induced by the corrosion products of a dental implant.

Embryotoxicity and genotoxicity evaluation of sediments from Yangtze River estuary using zebrafish (Danio rerio) embryos.

PubMed

Li, Qian; Chen, Ling; Liu, Li; Wu, Lingling

2016-03-01

Sediments function both as a sink and a source of pollutants in aquatic ecosystems and may impose serious effects on benthic organisms and human health. As one of the largest estuaries in the world, the Yangtze River estuary suffers from abundant wastewater from the coastal cities. In this study, the zebrafish (Danio rerio) embryos were employed in the fish embryo test and a comet assay to evaluate the embryotoxicity and genotoxicity of the sediments from the Yangtze River estuary, respectively. Results showed that the sediments from the Yangtze River estuary significantly increased mortality, induced development abnormalities, and reduced hatching rate and heart rate of zebrafish embryos after 96 h of exposure. Significant genotoxicity was observed in the samples relative to the controls. Relatively low-level embryotoxicity and genotoxicity of sediments were found in the Yangtze River compared with other river systems. Toxic responses were also discussed in relation to the analyzed organic contaminants in sediments. More attention should be paid to non-priority pollutant monitoring in the Yangtze River estuary.

In vitro assessment of the genotoxic and cytotoxic effects of boiled juice (tucupi) from Manihot esculenta Crantz roots.

PubMed

Cunha, L A; Mota, T C; Cardoso, P C S; Alcântara, D D F Á; Burbano, R M R; Guimarães, A C; Khayat, A S; Rocha, C A M; Bahia, M O

2016-10-05

The population of Pará (a state in Brazil) has a very characteristic food culture, as a majority of the carbohydrates consumed are obtained from cassava (Manihot esculenta Crantz) derivatives. Tucupi is the boiled juice of cassava roots that plays a major role in the culinary footprint of Pará. Before boiling, this juice is known as manipueira and contains linamarin, a toxic glycoside that can decompose to hydrogen cyanide. In this study, the cytotoxic and genotoxic effects of tucupi on cultured human lymphocytes were assessed using the comet assay and detection of apoptosis and necrosis by differential fluorescent staining with acridine orange-ethidium bromide. Tucupi concentrations (v/v) were determined using the methylthiazole tetrazolium biochemical test. Concentrations of tucupi that presented no genotoxic effects (2, 4, 8, and 16%) were used in our experiments. The results showed that under our study conditions, tucupi exerted no genotoxic effects; however, cytotoxic effects were observed with cell death mainly induced by necrosis. These effects may be related to the presence of hydrogen cyanide in the juice.

Beryllium metal I. experimental results on acute oral toxicity, local skin and eye effects, and genotoxicity.

PubMed

Strupp, Christian

2011-01-01

The toxicity of soluble metal compounds is often different from that of the parent metal. Since no reliable data on acute toxicity, local effects, and mutagenicity of beryllium metal have ever been generated, beryllium metal powder was tested according to the respective Organisation for Economical Co-Operation and Development (OECD) guidelines. Acute oral toxicity of beryllium metal was investigated in rats and local effects on skin and eye in rabbits. Skin-sensitizing properties were investigated in guinea pigs (maximization method). Basic knowledge about systemic bioavailability is important for the design of genotoxicity tests on poorly soluble substances. Therefore, it was necessary to experimentally compare the capacities of beryllium chloride and beryllium metal to form ions under simulated human lung conditions. Solubility of beryllium metal in artificial lung fluid was low, while solubility in artificial lysosomal fluid was moderate. Beryllium chloride dissolution kinetics were largely different, and thus, metal extracts were used in the in vitro genotoxicity tests. Genotoxicity was investigated in vitro in a bacterial reverse mutagenicity assay, a mammalian cell gene mutation assay, a mammalian cell chromosome aberration assay, and an unscheduled DNA synthesis (UDS) assay. In addition, cell transformation was tested in a Syrian hamster embryo cell assay, and potential inhibition of DNA repair was tested by modification of the UDS assay. Beryllium metal was found not to be mutagenic or clastogenic based on the experimental in vitro results. Furthermore, treatment with beryllium metal extracts did not induce DNA repair synthesis, indicative of no DNA-damaging potential of beryllium metal. A cell-transforming potential and a tendency to inhibit DNA repair when the cell is severely damaged by an external stimulus were observed. Beryllium metal was also found not to be a skin or eye irritant, not to be a skin sensitizer, and not to have relevant acute oral toxic properties.

An assessment of the genotoxicity and human health risk of topical use of kojic acid [5-hydroxy-2-(hydroxymethyl)-4H-pyran-4-one].

PubMed

Nohynek, Gerhard J; Kirkland, David; Marzin, Daniel; Toutain, Herve; Leclerc-Ribaud, Christele; Jinnai, Hiroyuki

2004-01-01

Kojic acid (KA), a natural substance produced by fungi or bacteria, such as Aspergillus, Penicillium or Acetobacter spp, is contained in traditional Japanese fermented foods and is used as a dermatological skin-lightening agent. High concentrations of KA (>or=1000 microg/plate) were mutagenic in S. typhimurium strains TA 98, TA 100, TA 1535, TA102 and E. coli WP2uvrA, but not in TA 1537. An Ames test following the "treat and plate" protocol was negative. A chromosome aberration test in V79 cells following a robust protocol showed only a marginal increase in chromosome aberrations at cytotoxic concentrations after prolonged (>or=18 h) exposure. No genotoxic activity was observed for hprt mutations either in mouse lymphoma or V79 cells, or in in vitro micronucleus tests in human keratinocytes or hepatocytes. All in vivo genotoxicity studies on KA doses were negative, including mouse bone marrow micronucleus tests after single or multiple doses, an in vivo/in vitro unscheduled DNA synthesis (UDS) test, or a study in the liver of the transgenic Muta(TM) Mouse. On the basis of pharmacokinetic studies in rats and in vitro absorption studies in human skin, the systemic exposure of KA in man following its topical application is estimated to be in the range of 0.03-0.06 mg/kg/day. Comparing these values with the NOAEL in oral subchronic animal studies (250 mg/kg/day), the calculated margin of safety would be 4200- to 8900-fold. Comparing human exposure with the doses that were negative for micronuclei, UDS and gene mutations in vivo, the margins of safety are 16000 to 26000-fold. In conclusion, the topical use of KA as a skin lightening agent results in minimal exposure that poses no or negligible risk of genotoxicity or toxicity to the consumer.

The Allium Test--A Simple, Eukaryote Genotoxicity Assay.

ERIC Educational Resources Information Center

Babich, H.; Segall, M. A.; Fox, K. D.

1997-01-01

Explains the allium test in which roots are excised from onion bulblets grown in aqueous solutions of a test agent. Root tips are then isolated and stained with aceto-orcein, and chromosomal aberrations are microscopically observed. (Author/AIM)

The various aspects of genetic and epigenetic toxicology: testing methods and clinical applications.

PubMed

Ren, Ning; Atyah, Manar; Chen, Wan-Yong; Zhou, Chen-Hao

2017-05-22

Genotoxicity refers to the ability of harmful substances to damage genetic information in cells. Being exposed to chemical and biological agents can result in genomic instabilities and/or epigenetic alterations, which translate into a variety of diseases, cancer included. This concise review discusses, from both a genetic and epigenetic point of view, the current detection methods of different agents' genotoxicity, along with their basic and clinical relation to human cancer, chemotherapy, germ cells and stem cells.

Genotoxicity of Dyes Present in Colored Smoke Munitions.

DTIC Science & Technology

1986-07-07

Salmonella bacteria with and without S-9 ..... .......... 32 10. Mutagenic activity of Disperse Red 15 in TA-1538 stain of Salmonella bacteria with and...0.50 4 𔃾 4 MNNG 0 05 - . ..... I . ~*- A191 735 GENOTOXICITY OF DYES PRESENT IN COLORED SMOKE MUNITIONS 2/2 I (U) L VELACE BIOMEDICAL AND ENVIRONMENTAL...for the Salmonella I mutagenicity test. Mutat. Res. 113:173-215. i Perry, P. and S. wolr. 1974. New gieinsa ineLhod for differential staining I of

Polyvinyl polypyrrolidone attenuates genotoxicity of silver nanoparticles synthesized via green route, tested in Lathyrus sativus L. root bioassay.

PubMed

Panda, Kamal K; Achary, V Mohan M; Phaomie, Ganngam; Sahu, Hrushi K; Parinandi, Narasimham L; Panda, Brahma B

2016-08-01

The silver nanoparticles (AgNPs) were synthesized extracellularly from silver nitrate (AgNO3) using kernel extract from ripe mango Mengifera indica L. under four different reaction conditions of the synthesis media such as the (i) absence of the reducing agent, trisodium citrate (AgNPI), (ii) presence of the reducing agent (AgNPII), (iii) presence of the cleansing agent, polyvinyl polypyrrolidone, PVPP (AgNPIII), and (iv) presence of the capping agent, polyvinyl pyrrolidone, PVP (AgNPIV). The synthesis of the AgNPs was monitored by UV-vis spectrophotometry. The AgNPs were characterised by the energy-dispersive X-ray spectroscopy, transmission electron microscopy, X-ray diffraction, and small-angle X-ray scattering. Functional groups on the AgNPs were established by the Fourier transform infrared spectroscopy. The AgNPs (AgNPI, AgNPII, AgNPIII and AgNPIV) were spherical in shape with the diameters and size distribution-widths of 14.0±5.4, 19.2±6.6, 18.8±6.6 and 44.6±13.2nm, respectively. Genotoxicity of the AgNPs at concentrations ranging from 1 to 100mgL(-1) was determined by the Lathyrus sativus L. root bioassay and several endpoint assays including the generation of reactive oxygen species and cell death, lipid peroxidation, mitotic index, chromosome aberrations (CA), micronucleus formation (MN), and DNA damage as determined by the Comet assay. The dose-dependent induction of genotoxicity of the silver ion (Ag(+)) and AgNPs was in the order Ag(+)>AgNPII>AgNPI>AgNPIV>AgNPIII that corresponded with their relative potencies of induction of DNA damage and oxidative stress. Furthermore, the findings underscored the CA and MN endpoint-based genotoxicity assay which demonstrated the genotoxicity of AgNPs at concentrations (≤10mgL(-1)) lower than that (≥10mgL(-1)) tested in the Comet assay. This study demonstrated the protective action of PVPP against the genotoxicity of AgNPIII which was independent of the size of the AgNPs in the L. sativus L. root bioassay system. Copyright © 2016 Elsevier B.V. All rights reserved.

Genotoxicity of 2-bromo-3′-chloropropiophenone

DOE Office of Scientific and Technical Information (OSTI.GOV)

Meng, Fanxue; Yan, Jian; Li, Yan

2013-07-15

Impurities are present in any drug substance or drug product. They can be process-related impurities that are not completely removed during purification or are formed due to the degradation of the drug substance over the product shelf-life. Unlike the drug substance, impurities generally do not have beneficial effects and may present a risk without associated benefit. Therefore, their amount should be minimized. 2-Bromo-3′-chloropropiophenone (BCP) is an impurity of bupropion, a second-generation antidepressant and a smoking cessation aid. The United States Pharmacopeia recommends an acceptable level for BCP that is not more than 0.1% of the bupropion. Because exposure to genotoxicmore » impurities even at low levels is of significant concern, it is important to determine whether or not BCP is genotoxic. Therefore, in this study the Ames test and the in vitro micronucleus assay were conducted to evaluate the genotoxicity of BCP. BCP was mutagenic with S9 metabolic activation, increasing the mutant frequencies in a concentration-dependent manner, up to 22- and 145-fold induction over the controls in Salmonella strains TA100 and TA1535, respectively. BCP was also positive in the in vitro micronucleus assay, resulting in up to 3.3- and 5.1-fold increase of micronucleus frequency for treatments in the absence and presence of S9, respectively; and 9.9- and 7.4-fold increase of aneuploidies without and with S9, respectively. The addition of N-acetyl-L-cysteine, an antioxidant, reduced the genotoxicity of BCP in both assays. Further studies showed that BCP treatment resulted in induction of reactive oxygen species (ROS) in the TK6 cells. The results suggest that BCP is mutagenic, clastogenic, and aneugenic, and that these activities are mediated via generation of reactive metabolites. - Highlights: • 2-Bromo-3′-chloropropiophenone is an impurity of bupropion. • BCP was positive in both the Ames test and the in vitro micronucleus assay. • It induced high frequencies of mutations, micronuclei and hypodiploids. • It induced ROS and addition of NAC blocked the genotoxicity of BCP. • Its genotoxic action is possibly mediated via generation of reactive metabolites.« less

Automation and validation of micronucleus detection in the 3D EpiDerm™ human reconstructed skin assay and correlation with 2D dose responses.

PubMed

Chapman, K E; Thomas, A D; Wills, J W; Pfuhler, S; Doak, S H; Jenkins, G J S

2014-05-01

Recent restrictions on the testing of cosmetic ingredients in animals have resulted in the need to test the genotoxic potential of chemicals exclusively in vitro prior to licensing. However, as current in vitro tests produce some misleading positive results, sole reliance on such tests could prevent some chemicals with safe or beneficial exposure levels from being marketed. The 3D human reconstructed skin micronucleus (RSMN) assay is a promising new in vitro approach designed to assess genotoxicity of dermally applied compounds. The assay utilises a highly differentiated in vitro model of the human epidermis. For the first time, we have applied automated micronucleus detection to this assay using MetaSystems Metafer Slide Scanning Platform (Metafer), demonstrating concordance with manual scoring. The RSMN assay's fixation protocol was found to be compatible with the Metafer, providing a considerably shorter alternative to the recommended Metafer protocol. Lowest observed genotoxic effect levels (LOGELs) were observed for mitomycin-C at 4.8 µg/ml and methyl methanesulfonate (MMS) at 1750 µg/ml when applied topically to the skin surface. In-medium dosing with MMS produced a LOGEL of 20 µg/ml, which was very similar to the topical LOGEL when considering the total mass of MMS added. Comparisons between 3D medium and 2D LOGELs resulted in a 7-fold difference in total mass of MMS applied to each system, suggesting a protective function of the 3D microarchitecture. Interestingly, hydrogen peroxide (H2O2), a positive clastogen in 2D systems, tested negative in this assay. A non-genotoxic carcinogen, methyl carbamate, produced negative results, as expected. We also demonstrated expression of the DNA repair protein N-methylpurine-DNA glycosylase in EpiDerm™. Our preliminary validation here demonstrates that the RSMN assay may be a valuable follow-up to the current in vitro test battery, and together with its automation, could contribute to minimising unnecessary in vivo tests by reducing in vitro misleading positives.

Physicochemical characteristics, mutagenicity and genotoxicity of airborne particles under industrial and rural influences in Northern Lebanon.

PubMed

Melki, Pamela N; Ledoux, Frédéric; Aouad, Samer; Billet, Sylvain; El Khoury, Bilal; Landkocz, Yann; Abdel-Massih, Roula M; Courcot, Dominique

2017-08-01

In this work, the main objectives were to assess the mutagenic and genotoxic effects of fine particulate matter collected in an industrial influenced site in comparison with a non-industrial influenced one (rural site) and to relate the particulate matter (PM) composition to the observed genotoxic effects. At the industrial influenced site, higher concentrations of phosphates, trace metals, and polycyclic aromatic hydrocarbons (PAHs) in particles could be related to the contributions of quarries, fertilizer producer, cement plants, and tires burning. Gasoline and diesel combustion contributions were evidenced in particles collected at both sites. Particles collected under industrial influence showed a higher mutagenic potential on three tested strains of Salmonella typhimurium (TA98, YG1041, and TA102), and especially on the YG1041, compared to particles from the rural site. Furthermore, only particles collected in the vicinity of the industrial site showed a tendency to activate the SOS responses in Escherichia coli PQ37, which is indicative of DNA damage as a result of exposure of the bacteria cells to the action of mutagenic samples. The mutagenicity and genotoxicity of the industrial PM 2.5-0.3 particulates may be attributed to its composition especially in organic compounds. This study showed that proximity of industries can affect local PM composition as well as PM genotoxic and mutagenic potential.

Chlorination of oxybenzone: Kinetics, transformation, disinfection byproducts formation, and genotoxicity changes.

PubMed

Zhang, Shujuan; Wang, Xiaomao; Yang, Hongwei; Xie, Yuefeng F

2016-07-01

UV filters are a kind of emerging contaminant, and their transformation behavior in water treatment processes has aroused great concern. In particular, toxic products might be produced during reaction with disinfectants during the disinfection process. As one of the most widely used UV filters, oxybenzone has received significant attention, because its transformation and toxicity changes during chlorine oxidation are a concern. In our study, the reaction between oxybenzone and chlorine followed pseudo-first-order and second-order kinetics. Three transformation products were detected by LC-MS/MS, and the stability of products followed the order of tri-chloro-methoxyphenoyl > di-chlorinated oxybenzone > mono-chlorinated oxybenzone. Disinfection byproducts (DBPs) including chloroform, trichloroacetic acid, dichloroacetic acid and chloral hydrate were quickly formed, and increased at a slower rate until their concentrations remained constant. The maximum DBP/oxybenzone molar yields for the four compounds were 12.02%, 6.28%, 0.90% and 0.23%, respectively. SOS/umu genotoxicity test indicated that genotoxicity was highly elevated after chlorination, and genotoxicity showed a significantly positive correlation with the response of tri-chloro-methoxyphenoyl. Our results indicated that more genotoxic transformation products were produced in spite of the elimination of oxybenzone, posing potential threats to drinking water safety. This study shed light on the formation of DBPs and toxicity changes during the chlorination process of oxybenzone. Copyright © 2016 Elsevier Ltd. All rights reserved.

Comet assay with gill cells of Mytilus galloprovincialis end point tools for biomonitoring of water antibiotic contamination: Biological treatment is a reliable process for detoxification.

PubMed

Mustapha, Nadia; Zouiten, Amina; Dridi, Dorra; Tahrani, Leyla; Zouiten, Dorra; Mosrati, Ridha; Cherif, Ameur; Chekir-Ghedira, Leila; Mansour, Hedi Ben

2016-04-01

This article investigates the ability of Pseudomonas peli to treat industrial pharmaceuticals wastewater (PW). Liquid chromatography-mass spectrometry (MS)/MS analysis revealed the presence, in this PW, of a variety of antibiotics such as sulfathiazole, sulfamoxole, norfloxacine, cloxacilline, doxycycline, and cefquinome.P. peli was very effective to be grown in PW and inducts a remarkable increase in chemical oxygen demand and biochemical oxygen demand (140.31 and 148.51%, respectively). On the other hand, genotoxicity of the studied effluent, before and after 24 h of shaking incubation with P. peli, was evaluated in vivo in the Mediterranean wild mussels Mytilus galloprovincialis using comet assay for quantification of DNA fragmentation. Results show that PW exhibited a statistically significant (p< 0.001) genotoxic effect in a dose-dependent manner; indeed, the percentage of genotoxicity was 122.6 and 49.5% after exposure to 0.66 ml/kg body weight (b.w.); 0.33 ml/kg b.w. of PW, respectively. However, genotoxicity decreased strongly when tested with the PW obtained after incubation with P. peli We can conclude that using comet assay genotoxicity end points are useful tools to biomonitor the physicochemical and biological quality of water. Also, it could be concluded that P. peli can treat and detoxify the studied PW. © The Author(s) 2013.

Genotoxicity assessment of membrane concentrates of landfill leachate treated with Fenton reagent and UV-Fenton reagent using human hepatoma cell line.

PubMed

Wang, Guifang; Lu, Gang; Yin, Pinghe; Zhao, Ling; Yu, Qiming Jimmy

2016-04-15

Membrane concentrates of landfill leachates contain organic and inorganic contaminants that could be highly toxic and carcinogenic. In this paper, the genotoxicity of membrane concentrates before and after Fenton and UV-Fenton reagent was assessed. The cytotoxicity and genotoxicity was determined by using the methods of methyltetrazolium (MTT), cytokinesis-block micronucleus (CBMN) and comet assay in human hepatoma cells. MTT assay showed a cytotoxicity of 75% after 24h of exposure to the highest tested concentration of untreated concentrates, and no cytotoxocity for UV-Fenton and Fenton treated concentrates. Both CBMN and comet assays showed increased levels of genotoxicity in cells exposed to untreated concentrates, compared to those occurred in cells exposed to UV-Fenton and Fenton reagent treated concentrates. There was no significant difference between negative control and UV-Fenton treated concentrates for micronucleus and comet assay parameters. UV-Fenton and Fenton treatment, especially the former, were effective methods for degradation of bisphenol A and nonylphenol in concentrates. These findings showed UV-Fenton and Fenton reaction were effective methods for treatment of such complex concentrates, UV-Fenton reagent provided toxicological safety of the treated effluent, and the genotoxicity assays were found to be feasible tools for assessment of toxicity risks of complex concentrates. Copyright © 2016 Elsevier B.V. All rights reserved.

Improved in silico prediction of carcinogenic potency (TD50) and the risk specific dose (RSD) adjusted Threshold of Toxicological Concern (TTC) for genotoxic chemicals and pharmaceutical impurities.

PubMed

Contrera, Joseph F

2011-02-01

The Threshold of Toxicological Concern (TTC) is a level of exposure to a genotoxic impurity that is considered to represent a negligible risk to humans. The TTC was derived from the results of rodent carcinogenicity TD50 values that are a measure of carcinogenic potency. The TTC currently sets a default limit of 1.5 μg/day in food contact substances and pharmaceuticals for all genotoxic impurities without carcinogenicity data. Bercu et al. (2010) used the QSAR predicted TD50 to calculate a risk specific dose (RSD) which is a carcinogenic potency adjusted TTC for genotoxic impurities. This promising approach is currently limited by the software used, a combination of MC4PC (www.multicase.com) and a Lilly Inc. in-house software (VISDOM) that is not available to the public. In this report the TD50 and RSD were predicted using a commercially available software, SciQSAR (formally MDL-QSAR, www.scimatics.com) employing the same TD50 training data set and external validation test set that was used by Bercu et al. (2010). The results demonstrate the general applicability of QSAR predicted TD50 values to determine the RSDs for genotoxic impurities and the improved performance of SciQSAR for predicting TD50 values. Copyright © 2010 Elsevier Inc. All rights reserved.

Contaminant bioavailability in soil and phytotoxicity/genotoxicity tests in Vicia faba L.: a case study of boron contamination.

PubMed

Barbafieri, Meri; Giorgetti, Lucia

2016-12-01

In this work, the model plant for genotoxicity studies Vicia faba L. was used to investigate the relation between Boron (B) content and bioavailability in soil and plant genotoxic/phytotoxic response. A total of nine soil samples were investigated: two soil samples were collected from a B-polluted industrial area in Cecina (Tuscany, Italy), the other samples were obtained by spiking control soil (from a not polluted area of the basin) with seven increased doses of B, from about 20 to 100 mg B kg -1 . As expected, B availability, evaluated by chemical extraction, was higher (twofold) in spiked soils when compared with collected polluted soils with the same B total content. To analyze the phytotoxic effects of B, seed germination, root elongation, biomass production, and B accumulation in plant tissues were considered in V. faba plants grown in the various soils. Moreover, the cytotoxic/genotoxic effects of B were investigated in root meristems by mitotic index (MI) and micronuclei frequency (MCN) analysis. The results highlighted that V. faba was a B-sensitive plant and the appearance of phytotoxic effects, which altered plant growth parameters, were linearly correlated to the bioavailable B concentration in soils. Concerning the occurrence of cytotoxic/genotoxic effects induced by B, no linear correlation was observed even if MCN frequency was logarithmic correlated with the concentration of B bioavailable in soils.

Evaluation of environmental genotoxicity by comet assay in Columba livia.

PubMed

González-Acevedo, Anahi; García-Salas, Juan A; Gosálvez, Jaime; Fernández, José Luis; Dávila-Rodríguez, Martha I; Cerda-Flores, Ricardo M; Méndez-López, Luis F; Cortés-Gutiérrez, Elva I

2016-01-01

The concentrations of recognized or suspected genotoxic and carcinogenic agents found in the air of large cities and, in particular, developing countries, have raised concerns about the potential for chronic health effects in the populations exposed to them. The biomonitoring of environmental genotoxicity requires the selection of representative organisms as "sentinels," as well as the development of suitable and sensitive assays, such as those aimed at assessing DNA damage. The aim of this study was to evaluate DNA damage levels in erythrocytes from Columba livia living in the metropolitan area of Monterrey, Mexico, compared with control animals via comet assay, and to confirm the results via Micronuclei test (MN) and DNA breakage detection-fluorescence in situ hybridization (DBD-FISH). Our results showed a significant increase in DNA migration in animals from the area assayed compared with that observed in control animals sampled in non-contaminated areas. These results were confirmed by MN test and DBD-FISH. In conclusion, these observations confirm that the examination of erythrocytes from Columba livia via alkaline comet assay provides a sensitive and reliable end point for the detection of environmental genotoxicants.

Effects on DNA repair in human lymphocytes exposed to the food dye tartrazine yellow.

PubMed

Soares, Bruno Moreira; Araújo, Taíssa Maíra Thomaz; Ramos, Jorge Amando Batista; Pinto, Laine Celestino; Khayat, Bruna Meireles; De Oliveira Bahia, Marcelo; Montenegro, Raquel Carvalho; Burbano, Rommel Mario Rodríguez; Khayat, André Salim

2015-03-01

Tartrazine is a food additive that belongs to a class of artificial dyes and contains an azo group. Studies about its genotoxic, cytotoxic and mutagenic effects are controversial and, in some cases, unsatisfactory. This work evaluated the potential in vitro cytotoxicity, genotoxicity and effects on DNA repair of human lymphocytes exposed to the dye. We assessed the cytotoxicity of tartrazine by 3-(4,5-Dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide test and the response of DNA repair through comet assay (alkaline version). We used different concentrations of the dye, ranging from 0.25-64.0 mM. The results demonstrated that tartrazine has no cytotoxic effects. However, this dye had a significant genotoxic effect at all concentrations tested. Although most of the damage was amenable to repair, some damage remained higher than positive control after 24 h of repair. These data demonstrate that tartrazine may be harmful to health and its prolonged use could trigger carcinogenesis. Copyright© 2015 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.

Genotoxic and mutagenic effects of polluted surface water in the midwestern region of Brazil using animal and plant bioassays

PubMed Central

Dourado, Priscila Leocádia Rosa; da Rocha, Monyque Palagano; Roveda, Liriana Mara; Raposo, Jorge Luiz; Cândido, Liliam Sílvia; Cardoso, Claudia Andréa Lima; Morales, Maria Aparecida Marin; de Oliveira, Kelly Mari Pires; Grisolia, Alexeia Barufatti

2016-01-01

Abstract This study aimed to evaluate DNA damage in animal and plant cells exposed to water from the Água Boa stream (Dourados, Mato Grosso do Sul, Brazil) by using bioassays, and to identify the chemical compounds in the water to determine the water quality in the area. Through the cytotoxicity bioassay with Allium cepa, using micronucleus test, and comet assay, using Astyanax altiparanae fish, the results indicated that biological samples were genetically altered. Micronuclei were observed in erythrocytes of A. altiparanae after exposure to water from locations close to industrial waste discharge. The highest DNA damage observed with the comet assay in fish occurred with the exposure to water from locations where the presence of metals (Cu, Pb, Cd, Ni) was high, indicating the possibility of genotoxic effects of these compounds. Thus, these results reinforce the importance of conducting genotoxicity tests for developing management plans to improve water quality, and indicate the need for waste management before domestic and industrial effluents are released into the rivers and streams. PMID:27801481

The history, genotoxicity and carcinogenicity of carbon-based fuels and their emissions: part 4 - alternative fuels.

PubMed

Claxton, Larry D

2015-01-01

Much progress has been made in reducing the pollutants emitted from various combustors (including diesel engines and power plants) by the use of alternative fuels; however, much more progress is needed. Not only must researchers improve fuels and combustors, but also there is a need to improve the toxicology testing and analytical chemistry methods associated with these complex mixtures. Emissions from many alternative carbonaceous fuels are mutagenic and carcinogenic. Depending on their source and derivation, alternative carbonaceous fuels before combustion may or may not be genotoxic; however, in order to know their genotoxicity, appropriate chemical analysis and/or bioassay must be performed. Newly developed fuels and combustors must be tested to determine if they provide a public health advantage over existing technologies - including what tradeoffs can be expected (e.g., decreasing levels of PAHs versus increasing levels of NOx and possibly nitroarenes in ambient air). Another need is to improve exposure estimations which presently are a weak link in doing risk analyses. Copyright © 2014 Elsevier B.V. All rights reserved.

Protective effects of acerola juice on genotoxicity induced by iron in vivo

PubMed Central

Horta, Roberta Nunes; Kahl, Vivian Francilia Silva; Sarmento, Merielen da Silva; Nunes, Marisa Fernanda Silva; Porto, Carem Rejane Maglione; de Andrade, Vanessa Moraes; Ferraz, Alexandre de Barros Falcão; Silva, Juliana Da

2016-01-01

Abstract Metal ions such as iron can induce DNA damage by inducing reactive oxygen species (ROS) and oxidative stress. Vitamin C is one of the most widely consumed antioxidants worldwide, present in many fruits and vegetables, especially inMalpighia glabra L., popularly known as acerola, native to Brazil. Acerola is considered a functional fruit due to its high antioxidant properties and phenolic contents, and therefore is consumed to prevent diseases or as adjuvant in treatment strategies. Here, the influence of ripe and unripe acerola juices on iron genotoxicity was analyzed in vivo using the comet assay and micronucleus test. The comet assay results showed that acerola juice exerted no genotoxic or antigenotoxic activity. Neither ripe nor unripe acerola juices were mutagenic to animals treated with juices, in micronucleus test. However, when compared to iron group, the pre-treatment with acerola juices exerted antimutagenic activity, decreasing significantly micronucleus mean values in bone marrow. Stage of ripeness did not influence the interaction of acerola compounds with DNA, and both ripe and unripe acerola juices exerted protective effect over DNA damage generated by iron. PMID:27007905

Effects of Jatropha curcas oil in Lactuca sativa root tip bioassays.

PubMed

Andrade-Vieira, Larissa F; Botelho, Carolina M; Laviola, Bruno G; Palmieri, Marcel J; Praça-Fontes, Milene M

2014-03-01

Jatropha curcas L. (Euphorbiaceae) is important for biofuel production and as a feed ingredient for animal. However, the presence of phorbol esters in the oil and cake renders the seeds toxic. The toxicity of J. curcas oil is currently assessed by testing in animals, leading to their death. The identification of toxic and nontoxic improved varieties is important for the safe use of J. curcas seeds and byproducts to avoid their environmental toxicity. Hence, the aim of this study was to propose a short-term bioassay using a plant as a model to screen the toxicity of J. curcas oil without the need to sacrifice any animals. The toxicity of J. curcas oil was evident in germination, root elongation and chromosomal aberration tests in Lactuca sativa. It was demonstrated that J. curcas seeds contain natural compounds that exert phyto-, cyto- and genotoxic effects on lettuce, and that phorbol esters act as aneugenic agents, leading to the formation of sticky chromosomes and c-metaphase cells. In conclusion, the tests applied have shown reproducibility, which is important to verify the extent of detoxification and to determine toxic doses, thus reducing the numbers of animals that would be used for toxicity tests.

Evaluating the genotoxicity of topoisomerase-targeted antibiotics

PubMed Central

Smart, Daniel J.; Lynch, Anthony M.

2012-01-01

Antibiotics like fluoroquinolones (FQs) that target bacterial type II topoisomerases pose a potential genotoxic risk due to interactions with mammalian topoisomerase II (TOPO II) counterparts. Inhibition of TOPO II can lead to the generation of clastogenic DNA double-strand breaks (DSBs) that can in turn manifest in mutagenesis. Thus, methods that allow early identification of drugs that present the greatest hazard are warranted. A rapid, medium-throughput and predictive genotoxicity screen that can be applied to bacterial type II topoisomerase inhibitors is described herein. Maximal induction of the DSB biomarker serine139-phosphorylated histone H2AX (γH2AX) in L5178Y cells was quantified via flow cytometry and correlated with data derived from the mouse lymphoma screen (MLS), a default assay used to rank genotoxic potential. When applied to a class of novel bacterial type II topoisomerase inhibitors (NBTIs) in lead-optimisation, maximal γH2AX induction >1.4-fold (relative to controls) identified 22/27 NBTIs that induced >6-fold relative mutation frequency (MF) in MLS. Moreover, response signatures comprising of γH2AX induction and G2M cell cycle arrest elucidated using this approach suggested that these NBTIs, primarily of the H class, operated via a TOPO II poison-like mechanism of action (MoA) similar to FQs. NBTIs that induced ≤6-fold relative MF, which were mainly A class-derived, had less impact on γH2AX (≤1.4-fold) and also evoked G1 arrest, indicating that their cytotoxic effects were likely mediated through a non-poison MoA. Concordance between assays was 86% (54/63) when 1.4- and 6-fold ‘cut offs’ were applied. These findings were corroborated through inspection of human TOPO IIα IC50 data as NBTIs exhibiting equivalent inhibitory capacities had differing genotoxic potencies. Deployed in an early screening capacity, the γH2AX by flow assay coupled with structure–activity relationship evaluation can provide insight into MoA and impact medicinal chemistry efforts, ultimately leading to the production of inherently safer molecules. PMID:22155972

Early genotoxic response and accumulation induced by waterborne copper, lead, and arsenic in European seabass, Dicentrarchus labrax.

PubMed

Canalejo, Antonio; Diaz-de-Alba, Margarita; Granado-Castro, M Dolores; Cordoba, Francisco; Espada-Bellido, Estrella; Galindo-Riaño, M Dolores; Torronteras, Rafael

2016-02-01

Cu, Pb, and As, which are among the most abundant metals in the aquatic environment, are also among the most health-threatened by causing diverse cellular injuries. The aim of this study was to assess and compare the potential early induction of genotoxic effects after waterborne Cu, Pb, and As exposure in European seabass, Dicentrarchus labrax, a commercial widely cultured fish, using the micronucleus (MN) assay in peripheral blood erythrocytes. Fish were exposed under laboratory conditions to nominal solutions ranging 0-10 mg/L for 24 and 96 h. Furthermore, actual metal ion concentrations were measured by inductively coupled plasma atomic emission spectroscopy (ICP-AES) or differential pulse anodic stripping voltammetry (DPASV) in water and four fish tissues differentially related to environmental exposition and metal accumulation, i.e. the gills, liver, muscle, and brain. Dose-dependent increases of micronuclei (MNi) frequency were observed after these very short exposures; based on measured metal concentrations in water, the genotoxic effect ordered as Cu > As > Pb. Significant genotoxic effect at 0.009 mg/L Cu, 0.57 mg/L Pb, and 0.01 mg/L As was seen. For Cu and Pb these are only slightly higher, but for As it is notably lower than the USEPA criteria of maximum concentration to prevent acute toxicity in aquatic organisms. Furthermore, genotoxicity was differentially related to metal accumulation. MNi frequency correlated positively with the content of Pb in all the organs, with the content of As in liver and gills and only with the content of Cu in the brain. In conclusion, our findings raised environmental concerns because these depicted a genotoxic potential of Cu, Pb, and As after a very short exposure to low but environmentally relevant concentrations, too close to regulatory thresholds. In addition, the MN test in D. labrax could be considered an early biomarker of genotoxicity induced by these metals in fish.

Evaluation of cytotoxicity, genotoxicity and teratogenicity of marine sediments from Qingdao coastal areas using in vitro fish cell assay, comet assay and zebrafish embryo test.

PubMed

Yang, Fan; Zhang, Qianqian; Guo, Huarong; Zhang, Shicui

2010-10-01

Marine sediments are often a final sink for numerous anthropogenic contaminants and may impose serious effects on benthic organisms and ecosystem. An in vitro cell assay using a cell line derived from flounder gill (FG) cells, an in vitro comet assay in FG cells, and an in vitro zebrafish embryo assay were used to evaluate the in vitro cytotoxicity (measured by MTT reduction), genotoxicity and teratogenicity of crude sediment extracts of Li Cang (LC), Zhan Qiao (ZQ) and Olympic Sailing Center (OSC) from Qingdao coastal area. Sediments from the three sites displayed different cytotoxicity, genotoxicity and teratogenicity potencies; however, all three assays yielded similar LOECs (lowest observed effect concentration) for each site, suggesting that the assays were equally sensitive to and suitable for initial screening of the LOECs of marine sediments. The cytotoxicity, genotoxicity and teratogenicity for these three sampling sites were in the same order of LC>ZQ>OSC, indicating different degrees of contamination. Interestingly, trials with the three sediment extracts at the doses inducing a similar cytotoxicity as evaluated with MTT reduction did not produce similar genotoxicity and teratogenicity, with the genotoxic and teratogenic activities of LC and ZQ extracts being markedly higher than those of OSC sediments. These findings indicate that cytotoxicity does not form a fully equivalent toxicity index with that of genotoxicity and teratogenicity. Therefore, in order to assess the true toxic potential of marine sediments, all three assays should be performed. Analysis of 16 EPA (US Environmental Protection Agency) priority PAHs in these three sediment samples showed a clear correlation between PAH concentrations and sediment toxicities, with a higher PAH content corresponding to higher toxicity although PAHs are surely not the only cause. Copyright © 2010 Elsevier Ltd. All rights reserved.

The protective effect of calcium against genotoxicity of lead acetate administration on bone marrow and spermatocyte cells of mice in vivo.

PubMed

Aboul-Ela, Ezzat I

2002-04-26

The protective effect of calcium given orally by gavage with two doses (40 and 80mg/kg body weight) was evaluated against clastogenecity induced by lead acetate with two concentrations (200 and 400mg/kg diet) on bone marrow and spermatocyte cells of mice in vivo. The parameter screened was percentage of chromosomal aberrations with and without gaps and sperm abnormalities. Statistical analyses indicated the protection efficacy of calcium with the high dose rather than the other in both types of mouse cells. The observation from the laboratory tests, dealing that lead acetate can be considered as an environmental genotoxic material. We recommended that it must be administered of calcium (as calcium chloride) as a protective agent to reduce the genotoxic effect of lead in the somatic and germ cells.

Genotoxicity Evaluation of an Urban River on Freshwater Planarian by RAPD Assay.

PubMed

Zhang, He-Cai; Liu, Tong-Yi; Shi, Chang-Ying; Chen, Guang-Wen; Liu, De-Zeng

2017-04-01

The aim of this study was to evaluate the genotoxic potential of an urban river - the Wei River in Xinxiang, China using randomly amplified polymorphic DNA (RAPD) assay in planarians. The results showed that the total number of polymorphic bands and varied bands in RAPD patterns of treated planarians decreased with the water sample site far away from the sewage outlet of a factory. In addition, the genome template stability of treated groups decreased and the degree of the decline was negatively related to the distance between the sample site and the sewage outlet, suggesting that the Wei River water had genotoxicity effects on planarians and strengthening the management of the Wei River was necessary. Furthermore, this work also indicated that RAPD assay in planarians was a very promising test for environmental monitoring studies.

In-vivo genotoxicity of the alkaloid drug pilocarpine nitrate in bone marrow cells and male germ cells of mice.

PubMed

Hegde, M J; Sujatha, T V

1995-10-01

Pilocarpine nitrate, an alkaloid drug of plant origin induces spindle disfunction in bone marrow cells of mice. Further studies were carried out to investigate its mutagenic effects in somatic and germ cells of mice by assessing chromosome aberrations at mitotic metaphase and as micronuclei in bone marrow cells and sperm-shape abnormality in cauda epididymides. The dose and time yield effects of the drug were investigated. The statistically significant results that were obtained for both chromosomal aberrations and micronucleus test but not for the sperm-shape abnormality test, indicated the genotoxicity of this compound in somatic cells but not in germ cells.

Isolation and Identification of Aspergillus fumigatus Mycotoxins on Growth Medium and Some Building Materials

PubMed Central

Nieminen, Susanna M.; Kärki, Riikka; Auriola, Seppo; Toivola, Mika; Laatsch, Hartmut; Laatikainen, Reino; Hyvärinen, Anne; von Wright, Atte

2002-01-01

Genotoxic and cytotoxic compounds were isolated and purified from the culture medium of an indoor air mold, Aspergillus fumigatus. One of these compounds was identified as gliotoxin, a known fungal secondary metabolite. Growth of A. fumigatus and gliotoxin production on some building materials were also studied. Strong growth of the mold and the presence of gliotoxin were detected on spruce wood, gypsum board, and chipboard under saturation conditions. PMID:12324333

Dose-Response Assessment of Four Genotoxic Chemicals in a Combined Mouse and Rat Micronucleus and Comet Assay Protocol

PubMed Central

Recio, Leslie; Hobbs, Cheryl; Caspary, William; Witt, Kristine L.

2012-01-01

The in vivo micronucleus (MN) assay has proven to be an effective measure of genotoxicity potential. However, sampling a single tissue (bone marrow) for a single indicator of genetic damage using the MN assay provides a limited genotoxicity profile. The in vivo alkaline (pH>13) Comet assay, which detects a broad spectrum of DNA damage, can be applied to a variety of rodent tissues following administration of test agents. To determine if the Comet assay is a useful supplement to the in vivo MN assay, a combined test protocol (MN/Comet assay) was conducted in male B6C3F1 mice and F344/N rats using four model genotoxicants: ethyl methanesulfonate (EMS), acrylamide (ACM), cyclophosphamide (CP), and vincristine sulfate (VS). Test compounds were administered on 4 consecutive days at 24-hour intervals (VS was administered to rats for 3 days); animals were euthanized 4 hours after the last administration. All compounds induced significant increases in micronucleated reticulocytes (MN-RET) in the peripheral blood of mice, and all but ACM induced MN-RET in rats. EMS and ACM induced significant increases in DNA damage, measured by the Comet assay, in multiple tissues of mice and rats. CP-induced DNA damage was detected in leukocytes and duodenum cells. VS, a spindle fiber disrupting agent, was negative in the Comet assay. Based on these results, the MN/Comet assay holds promise for providing more comprehensive assessments of potential genotoxicants, and the National Toxicology Program is presently using this combined protocol in its overall evaluation of the genotoxicity of substances of public health concern. PMID:20371966

Reliability of plant root comet assay in comparison with human leukocyte comet assay for assessment environmental genotoxic agents.

PubMed

Reis, Gabriela Barreto Dos; Andrade-Vieira, Larissa Fonseca; Moraes, Isabella de Campos; César, Pedro Henrique Souza; Marcussi, Silvana; Davide, Lisete Chamma

2017-08-01

Comet assay is an efficient test to detect genotoxic compounds based on observation of DNA damage. The aim of this work was to compare the results obtained from the comet assay in two different type of cells extracted from the root tips from Lactuca sativa L. and human blood. For this, Spent Pot Liner (SPL), and its components (aluminum and fluoride) were applied as toxic agents. SPL is a solid waste generated in industry from the aluminum mining and processing with known toxicity. Three concentrations of all tested solutions were applied and the damages observed were compared to negative and positive controls. It was observed an increase in the frequency of DNA damage for human leukocytes and plant cells, in all treatments. On human leukocytes, SPL induced the highest percentage of damage, with an average of 87.68%. For root tips cells of L. sativa the highest percentage of damage was detected for aluminum (93.89%). Considering the arbitrary units (AU), the average of nuclei with high levels of DNA fragmentation was significant for both cells type evaluated. The tested cells demonstrated equal effectiveness for detection of the genotoxicity induced by the SPL and its chemical components, aluminum and fluoride. Further, using a unique method, the comet assay, we proved that cells from root tips of Lactuca sativa represent a reliable model to detect DNA damage induced by genotoxic pollutants is in agreement of those observed in human leukocytes as model. So far, plant cells may be suggested as important system to assess the toxicological risk of environmental agents. Copyright © 2017 Elsevier Inc. All rights reserved.

Genotoxicity profile of fexinidazole--a drug candidate in clinical development for human African trypanomiasis (sleeping sickness).

PubMed

Tweats, David; Bourdin Trunz, Bernadette; Torreele, Els

2012-09-01

The parasitic disease human African trypanomiasis (HAT), also known as sleeping sickness, is a highly neglected fatal condition endemic in sub-Saharan Africa, which is poorly treated with medicines that are toxic, no longer effective or very difficult to administer. New, safe, effective and easy-to-use treatments are urgently needed. Many nitroimidazoles possess antibacterial and antiprotozoal activity and examples such as tinidazole are used to treat trichomoniasis and guardiasis, but concerns about toxicity including genotoxicity limit their usefulness. Fexinidazole, a 2-substituted 5-nitroimidazole rediscovered by the Drugs for Neglected Diseases initiative (DNDi) after extensive compound mining of public and pharmaceutical company databases, has the potential to become a short-course, safe and effective oral treatment, curing both acute and chronic HAT. This paper describes the genotoxicity profile of fexinidazole and its two active metabolites, the sulfoxide and sulfone derivatives. All the three compounds are mutagenic in the Salmonella/Ames test; however, mutagenicity is either attenuated or lost in Ames Salmonella strains that lack one or more nitroreductase(s). It is known that these enzymes can nitroreduce compounds with low redox potentials, whereas their mammalian cell counterparts cannot, under normal conditions. Fexinidazole and its metabolites have low redox potentials and all mammalian cell assays to detect genetic toxicity, conducted for this study either in vitro (micronucleus test in human lymphocytes) or in vivo (ex vivo unscheduled DNA synthesis in rats; bone marrow micronucleus test in mice), were negative. Thus, fexinidazole does not pose a genotoxic hazard to patients and represents a promising drug candidate for HAT. Fexinidazole is expected to enter Phase II clinical trials in 2012.

Aspects of nitrogen dioxide toxicity in environmental urban concentrations in human nasal epithelium

DOE Office of Scientific and Technical Information (OSTI.GOV)

Koehler, C.; Ginzkey, C.; Friehs, G.

Cytotoxicity and genotoxicity of nitrogen dioxide (NO{sub 2}) as part of urban exhaust pollution are widely discussed as potential hazards to human health. This study focuses on toxic effects of NO{sub 2} in realistic environmental concentrations with respect to the current limit values in a human target tissue of volatile xenobiotics, the epithelium of the upper aerodigestive tract. Nasal epithelial cells of 10 patients were cultured as an air-liquid interface and exposed to 0.01 ppm NO{sub 2}, 0.1 ppm NO{sub 2}, 1 ppm NO{sub 2}, 10 ppm NO{sub 2} and synthetic air for half an hour. After exposure, genotoxicity wasmore » evaluated by the alkaline single-cell microgel electophoresis (Comet) assay and by induction of micronuclei in the micronucleus test. Depression of proliferation and cytotoxic effects were determined using the micronucleus assay and trypan blue exclusion assay, respectively. The experiments revealed genotoxic effects by DNA fragmentation starting at 0.01 ppm NO{sub 2} in the Comet assay, but no micronucleus inductions, no changes in proliferation, no signs of necrosis or apoptosis in the micronucleus assay, nor did the trypan blue exclusion assay show any changes in viability. The present data reveal a possible genotoxicity of NO{sub 2} in urban concentrations in a screening test. However, permanent DNA damage as indicated by the induction of micronuclei was not observed. Further research should elucidate the effects of prolonged exposure.« less

Anti-inflammatory, antimycobacterial and genotoxic evaluation of Doliocarpus dentatus.

PubMed

Ishikawa, Raissa Borges; Leitão, Maicon Matos; Kassuya, Roberto Mikio; Macorini, Luis Fernando; Moreira, Flora Martinez Figueira; Cardoso, Claudia Andrea Lima; Coelho, Roberta Gomes; Pott, Arnildo; Gelfuso, Guilherme Martins; Croda, Julio; Oliveira, Rodrigo Juliano; Kassuya, Candida Aparecida Leite

2017-05-23

Doliocarpus dentatus is a medicinal plant widely used in Mato Grosso do Sul State for removing the swelling pain caused by the inflammation process and for treating urine retention. The genotoxic aspects and the anti-inflammatory and antimycobacterial activity of the ethanolic extract obtained from the leaves of D. dentatus (EEDd) were investigated. The EEDd was evaluated against Mycobacterium tuberculosis, and the compound composition was evaluated and identified by nuclear magnetic resonance (NMR). The mice received oral administration of EEDd (30-300mg/kg) in carrageenan models of inflammation, and EEDd (10-1000mg/kg) was assayed by the comet, micronucleus, and phagocytosis tests and by the peripheral leukocyte count. Phenols (204.04mg/g), flavonoids (89.17mg/g), and tannins (12.05mg/g) as well as sitosterol-3-O-β-D-glucopyranoside, kaempferol 3-O-α-L-rhamnopyranoside, betulinic acid and betulin were present in the EEDd. The value of minimal inhibitory concentration (MIC) of EEDd was 62.5µg/mL. The EEDd induced a significant decrease in the edema, mechanical hypersensitivity and leukocyte migration induced by carrageenan. The comet and micronucleus tests indicated that the EEDd was not genotoxic. The EEDd also did not change the phagocytic activity or the leukocyte perLipheral count. The EEDd does not display genotoxicity, phagocytosis and could act as an antimycobacterial and anti-inflammatory agent. This study should contribute to ensuring the safe use of EEDd. Copyright © 2017 Elsevier Ireland Ltd. All rights reserved.

Genotoxicity studies on DNA-interactive telomerase inhibitors with application as anti-cancer agents.

PubMed

Harrington, Dean J; Cemeli, Eduardo; Carder, Joanna; Fearnley, Jamie; Estdale, Sian; Perry, Philip J; Jenkins, Terence C; Anderson, Diana

2003-01-01

Telomerase-targeted strategies have aroused recent interest in anti-cancer chemotherapy, because DNA-binding drugs can interact with high-order tetraplex rather than double-stranded (duplex) DNA targets in tumour cells. However, the protracted cell-drug exposure times necessary for clinical application require that telomerase inhibitory efficacy must be accompanied by both low inherent cytotoxicity and the absence of mutagenicity/genotoxicity. For the first time, the genotoxicity of a number of structurally diverse DNA-interactive telomerase inhibitors is examined in the Ames test using six Salmonella typhimurium bacterial strains (TA1535, TA1537, TA1538, TA98, TA100, and TA102). DNA damage induced by each agent was also assessed using the Comet assay with human lymphocytes. The two assay procedures revealed markedly different genotoxicity profiles that are likely to reflect differences in metabolism and/or DNA repair between bacterial and mammalian cells. The mutational spectrum for a biologically active fluorenone derivative, shown to be mutagenic in the TA100 strain, was characterised using a novel and rapid assay method based upon PCR amplification of a fragment of the hisG46 allele, followed by RFLP analysis. Preliminary analysis indicates that the majority (84%) of mutations induced by this compound are C --> A transversions at position 2 of the missense proline codon of the hisG46 allele. However, despite its genotoxic bacterial profile, this fluorenone agent gave a negative response in the Comet assay, and demonstrates how unwanted systemic effects (e.g., cytotoxicity and genotoxicity) can be prevented or ameliorated through suitable molecular fine-tuning of a candidate drug in targeted human tumour cells. Copyright 2003 Wiley-Liss, Inc.

Cytotoxic and genotoxic characterization of aluminum and silicon oxide nanoparticles in macrophages.

PubMed

Hashimoto, Masanori; Imazato, Satoshi

2015-05-01

Although aluminum oxide and silicon oxide nanoparticles are currently available as dental materials, there is a lack of basic information concerning their biocompatibility. This study evaluates the biological responses of cultured macrophages (RAW264) to aluminum oxide (Al2O3NPs) and silicon oxide nanoparticles (SiO2NPs) by analyzing cytotoxicity and genotoxicity. The nanoparticles are amorphous and spherical, with diameters of 13 nm for the Al2O3NPs and 12 nm for the SiO2NPs. The cultured RAW264 are exposed to the nanoparticles (NPs) and examined for cytotoxicity using the WST-8 cell viability and Hoechst/PI apoptosis assay, for genotoxicity by micronucleus analysis, for changes in nuclear shape (deformed nuclei) and for comet assay using confocal microscopy, and micromorphological analysis is done using scanning and transmission electron microscopes. Nuclei and DNA damage because of exposure to both types of NPs is observed by inmunostaining genotoxicity testing. The cytotoxicity and genotoxicity are well correlated in this study. Numerous NPs are observed as large aggregates in vesicles, but less or nonexistent NP internalization is seen in the nucleus or cytoplasm. These morphological results suggest that a primary cause of cell disruption is the chemical changes of the NPs in the low pH of vesicles (i.e., ionization of Al2O3 or SiO2) for both types of oxide NPs. Although further research on the elution of NP concentrations on cell or tissue activity under simulated clinical conditions is required, NP concentrations over 200 μg/mL are large enough to induce cytotoxic and genotoxic effects to cells. Copyright © 2015 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

No evidence of the genotoxic potential of gold, silver, zinc oxide and titanium dioxide nanoparticles in the SOS chromotest.

PubMed

Nam, Sun-Hwa; Kim, Shin Woong; An, Youn-Joo

2013-10-01

Gold nanoparticles (Au NPs), silver nanoparticles (Ag NPs), zinc oxide nanoparticles (ZnO NPs) and titanium dioxide nanoparticles (TiO2 NPs) are widely used in cosmetic products such as preservatives, colorants and sunscreens. This study investigated the genotoxicity of Au NPs, Ag NPs, ZnO NPs and TiO2 NPs using the SOS chromotest with Escherichia coli PQ37. The maximum exposure concentrations for each nanoparticle were 3.23 mg l(-1) for Au NPs, 32.3 mg l(-1) for Ag NPs and 100 mg l(-1) for ZnO NPs and TiO2 NPs. Additionally, in order to compare the genotoxicity of nanoparticles and corresponding dissolved ions, the ions were assessed in the same way as nanoparticles. The genotoxicity of the titanium ion was not assessed because of the extremely low solubility of TiO2 NPs. Au NPs, Ag NPs, ZnO NPs, TiO2 NPs and ions of Au, Ag and Zn, in a range of tested concentrations, exerted no effects in the SOS chromotest, evidenced by maximum IF (IFmax) values of below 1.5 for all chemicals. Owing to the results, nanosized Au NPs, Ag NPs, ZnO NPs, TiO2 NPs and ions of Au, Ag and Zn are classified as non-genotoxic on the basis of the SOS chromotest used in this study. To the best of our knowledge, this is the first study to evaluate the genotoxicity of Au NPs, Ag NPs, ZnO NPs and TiO2 NPs using the SOS chromotest. Copyright © 2012 John Wiley & Sons, Ltd.

Genotoxicity of Turnera subulata and Spondias mombin × Spondias tuberosa Extracts from Brazilian Caatinga Biome.

PubMed

Senes-Lopes, Tiago Felipe; López, Jorge Alberto; do Amaral, Viviane Souza; Brandão-Neto, José; de Rezende, Adriana Augusto; da Luz, Jefferson Romáryo Duarte; Guterres, Zaira da Rosa; Almeida, Maria das Graças

2018-04-01

Medicinal plants have been used in primary healthcare since the earliest days of humankind. Turnera subulata and Spondias mombin × Spondias tuberosa are widely used in the Brazilian Northeast to treat several diseases. The aim of this study was to evaluate the genotoxic effects of the leaf extracts of these species by the somatic mutation and recombination test in the somatic cells of Drosophila melanogaster wings. The experiments were performed using standard and high-bioactivation cross and three concentrations of the test substance [aqueous extract (AET and AES) at 5.0, 10.0, and 20.0 mg/mL and ethanolic extract (EET and EES) and ethyl acetate fraction (EAFT and EAFS) at 0.625, 1.25, and 2.5 mg/mL]. Results indicated that the extracts and fractions induced spontaneous frequencies of mutant spots in both D. melanogaster crosses. Nevertheless, the highest concentrations of the tested plant chemical agents were responsible for the statistically significant genotypic effect. T. subulata and S. mombin × S. tuberosa displayed genotoxic effect under the experimental conditions. The results from this study are crucial as they indicated the deleterious and side effects, considering the indiscriminate use of the extracts of these plants for disease treatment.

Aluminum induces chromosome aberrations, micronuclei, and cell cycle dysfunction in root cells of Vicia faba.

PubMed

Yi, Min; Yi, Huilan; Li, Honghai; Wu, Lihua

2010-04-01

Aluminum (Al) exists naturally in air, water, and soil, and also in our diet. Al can be absorbed into the human body and accumulates in different tissues, which has been linked to the occurrence of Alzheimer's disease and various neurological disorders. By using Vicia cytogenetic tests, which are commonly used to monitor the genotoxicity of environmental pollutants, cytogenetic effects of aluminum (AlCl(3)) were investigated in this study. Present results showed that Al caused significant increases in the frequencies of micronuclei (MN) and anaphase chromosome aberrations in Vicia faba root tips exposed to Al over a concentration-tested range of 0.01-10 mM for 12 h. The frequency of micronucleated cells was higher in Al-treated groups at pH 4.5 than that at pH 5.8. Similarly, AlCl(3) treatment caused a decrease in the number of mitotic cells in a dose- and pH-dependent manner. The number of cells in each mitotic phase changed in Al-treated samples. Mitotic indices (MI) decreased with the increases of pycnotic cells. Our results demonstrate that aluminum chloride is a clear clastogenic/genotoxic and cytotoxic agent in Vicia root cells. The V. faba cytogenetic test could be used for the genotoxicity monitoring of aluminum water contamination.

A novel genotoxic aspect of thiabendazole as a photomutagen in bacteria and cultured human cells.

PubMed

Watanabe-Akanuma, Mie; Ohta, Toshihiro; Sasaki, Yu F

2005-09-15

Thiabendazole (TBZ) is a post-harvest fungicide commonly used on imported citrus fruits. We recently found that TBZ showed photomutagenicity with UVA-irradiation in the Ames test using plate incorporation method. In the present study, potential of DNA-damaging activity, mutagenicity, and clastogenicity were investigated by short pulse treatment for 10 min with TBZ (50-400 microg/ml) and UVA-irradiation (320-400 nm, 250 microW/cm2) in bacterial and human cells. UVA-irradiated TBZ caused DNA damage in Escherichia coli and human lymphoblastoid WTK1 cells assayed, respectively, by the umu-test and the single cell gel electrophoresis (comet) assay. In a modified Ames test using Salmonella typhimurium and E. coli, strong induction of -1 frameshift mutations as well as base-substitution mutations were detected. TBZ at 50-100 microg/ml with UVA-irradiation significantly induced micronuclei in WTK1 cells in the in vitro cytochalasin-B micronucleus assay. Pulse treatment for 10 min with TBZ alone did not show any genotoxicity. Although TBZ is a spindle poison that induces aneuploidy, we hypothesize that the photogenotoxicity of TBZ in the present study was produced by a different mechanism, probably by DNA adduct formation. We concluded that UVA-activated TBZ is genotoxic in bacterial and human cells in vitro.

A retrospective evaluation method for in vitro mammalian genotoxicity tests using cytotoxicity index transformation formulae.

PubMed

Fujita, Yurika; Kasamatsu, Toshio; Ikeda, Naohiro; Nishiyama, Naohiro; Honda, Hiroshi

2016-01-15

Although in vitro chromosomal aberration tests and micronucleus tests have been widely used for genotoxicity evaluation, false-positive results have been reported under strong cytotoxic conditions. To reduce false-positive results, the new Organization for Economic Co-operation and Development (OECD) test guideline (TG) recommends the use of a new cytotoxicity index, relative increase in cell count or relative population doubling (RICC/RPD), instead of the traditionally used index, relative cell count (RCC). Although the use of the RICC/RPD may result in different outcomes and require re-evaluation of tested substances, it is impractical to re-evaluate all existing data. Therefore, we established a method to estimate test results from existing RCC data. First, we developed formulae to estimate RICC/RPD from RCC without cell counts by considering cell doubling time and experiment time. Next, the accuracy of the cytotoxicity index transformation formulae was verified by comparing estimated RICC/RPD and measured RICC/RPD for 3 major chemicals associated with false-positive genotoxicity test results: ethyl acrylate, eugenol and p-nitrophenol. Moreover, 25 compounds with false-positive in vitro chromosomal aberration (CA) test results were re-evaluated to establish a retrospective evaluation method based on derived estimated RICC/RPD values. The estimated RICC/RPD values were in good agreement with the measured RICC/RPD values for every concentration and chemical, and the estimated RICC suggested the possibility that 12 chemicals (48%) with previously judged false-positive results in fact had negative results. Our method enables transformation of RCC data into RICC/RPD values with a high degree of accuracy and will facilitate comprehensive retrospective evaluation of test results. Copyright © 2015 Elsevier B.V. All rights reserved.

Genotoxicity Assessment of Drinking Water Disinfection Byproducts by DNA Damage and Repair Pathway Profiling Analysis.

PubMed

Lan, Jiaqi; Rahman, Sheikh Mokhlesur; Gou, Na; Jiang, Tao; Plewa, Micheal J; Alshawabkeh, Akram; Gu, April Z

2018-06-05

Genotoxicity is considered a major concern for drinking water disinfection byproducts (DBPs). Of over 700 DBPs identified to date, only a small number has been assessed with limited information for DBP genotoxicity mechanism(s). In this study, we evaluated genotoxicity of 20 regulated and unregulated DBPs applying a quantitative toxicogenomics approach. We used GFP-fused yeast strains that examine protein expression profiling of 38 proteins indicative of all known DNA damage and repair pathways. The toxicogenomics assay detected genotoxicity potential of these DBPs that is consistent with conventional genotoxicity assays end points. Furthermore, the high-resolution, real-time pathway activation and protein expression profiling, in combination with clustering analysis, revealed molecular level details in the genotoxicity mechanisms among different DBPs and enabled classification of DBPs based on their distinct DNA damage effects and repair mechanisms. Oxidative DNA damage and base alkylation were confirmed to be the main molecular mechanisms of DBP genotoxicity. Initial exploration of QSAR modeling using moleular genotoxicity end points (PELI) suggested that genotoxicity of DBPs in this study was correlated with topological and quantum chemical descriptors. This study presents a toxicogenomics-based assay for fast and efficient mechanistic genotoxicity screening and assessment of a large number of DBPs. The results help to fill in the knowledge gap in the understanding of the molecular mechanisms of DBP genotoxicity.

A Comprehensive Toxicological Safety Assessment of an Extract of Olea Europaea L. Leaves (Bonolive™).

PubMed

Clewell, Amy E; Béres, Erzsébet; Vértesi, Adél; Glávits, Róbert; Hirka, Gábor; Endres, John R; Murbach, Timothy S; Szakonyiné, Ilona Pasics

2016-01-01

A battery of toxicological studies was conducted to investigate the genotoxicity and repeated-dose oral toxicity of Bonolive™, a proprietary water-soluble extract of the leaves of the olive tree (Olea europaea L.), in accordance with internationally accepted protocols. There was no evidence of mutagenicity in a bacterial reverse mutation test and in an vitro mammalian chromosomal aberration test nor was any genotoxic activity observed in an in vivo mouse micronucleus test at concentrations up to the limit dose of 2000 mg/kg bw/d. Bonolive™ did not cause mortality or toxic effects in Crl:(WI)BR Wistar rats in a 90-day repeated-dose oral toxicity study at doses of 360, 600, and 1000 mg/kg bw/d. The no observed adverse effect level in the 90-day study was 1000 mg/kg bw/d for both male and female rats, the highest dose tested. © The Author(s) 2015.

A Toxicological Evaluation of a Standardized Hydrogenated Extract of Curcumin (CuroWhite™)

PubMed Central

Ravikumar, Alastimmanahalli Narasimhiah; Jacob, Joby

2018-01-01

A series of toxicological investigations were conducted in order to evaluate the genotoxic potential and repeated-dose oral toxicity of CuroWhite, a proprietary extract of curcumin that has been hydrogenated and standardized to not less than 25% hydrogenated curcuminoid content. All tests were conducted in general accordance with internationally accepted standards. The test item was not mutagenic in the bacterial reverse mutation test or in vitro mammalian chromosomal aberration test, and no in vivo genotoxic activity was observed in rat bone marrow in the micronucleus test. A 90-day repeated-dose study was conducted in male and female Sprague-Dawley rats. Two mortalities occurred in the main and satellite high-dose groups and were determined due to gavage error. No organ specific or other toxic effects of the test item were observed up to the maximum dose of 800 mg/kg bw/day, administered by gavage. NOAEL was, therefore, estimated as 800 mg/kg bw/day. PMID:29610573

A Toxicological Evaluation of a Standardized Hydrogenated Extract of Curcumin (CuroWhite™).

PubMed

Ravikumar, Alastimmanahalli Narasimhiah; Jacob, Joby; Gopi, Sreeraj; Jagannath, Tumkur Subbarao

2018-01-01

A series of toxicological investigations were conducted in order to evaluate the genotoxic potential and repeated-dose oral toxicity of CuroWhite, a proprietary extract of curcumin that has been hydrogenated and standardized to not less than 25% hydrogenated curcuminoid content. All tests were conducted in general accordance with internationally accepted standards. The test item was not mutagenic in the bacterial reverse mutation test or in vitro mammalian chromosomal aberration test, and no in vivo genotoxic activity was observed in rat bone marrow in the micronucleus test. A 90-day repeated-dose study was conducted in male and female Sprague-Dawley rats. Two mortalities occurred in the main and satellite high-dose groups and were determined due to gavage error. No organ specific or other toxic effects of the test item were observed up to the maximum dose of 800 mg/kg bw/day, administered by gavage. NOAEL was, therefore, estimated as 800 mg/kg bw/day.

[Cytotoxicity and genotoxicity of fluorides in human mucosa and lymphocytes].

PubMed

Kleinsasser, N H; Weissacher, H; Wallner, B C; Kastenbauer, E R; Harréus, U A

2001-04-01

Fluorides are widely used in dental health products and drinking water, due to their beneficial effects in caries-prophylaxis and -treatment. Nevertheless, irritation of the gingiva and oropharyngeal mucosa as well as in gastric mucosa is observed since neither local nor systemic application is restricted to the teeth. These effects may partly be attributed to a known cytotoxicity of fluorides. Whether fluorides also have genotoxic effects on human mucosa or lymphocytes as a possible factor in tumor initiation was investigated in this study. Human oropharyngeal epithelial cells and peripheral lymphocytes were incubated after single cell preparation with the aminefluoride Olaflur at concentrations of 2 ppm, 21 ppm, 35 ppm, 71 ppm and 213 ppm. The extent of cytotoxicity was investigated using the trypan blue exclusion test. Following incubation, electrophoresis for migration of DNA fragments, fluorescence staining and digital image analysis according to a standard protocol of the single cell microgel electrophoresis assay (Comet assay) followed. DNA damage was characterized using the Olive Tail Moment (OTM). For fluoride concentrations of 2 ppm to 35 ppm, non vital cells of less than 10% could be shown. After incubation with 71 ppm and 213 ppm Olaflur, there were 15% and 43% of damaged cells, respectively. Weak genotoxic effects on mucosal cells as well as on lymphocytes could be demonstrated at all concentrations tested. In fluoride concentrations of 213 ppm genotoxicity increased to max. OTM-levels of 23. Beside the cytotoxic effect of fluorides, also a minor genotoxic impact on human mucosa and on peripheral lymphocytes could be demonstrated using the Comet assay. Further investigations are warranted to examine fluorides in a model allowing for repeated or long term incubations on structurally intact human mucosa in vitro. Such a model will help to distinguish between DNA damage that may be repaired successfully and other impairments that may show an additive character in repetitive or chronic exposure in vivo.

Genotoxic and cytotoxic effects of different types of dental cement on normal cultured human lymphocytes.

PubMed

Bakopoulou, A; Mourelatos, D; Tsiftsoglou, A S; Giassin, N P; Mioglou, E; Garefis, P

2009-01-31

In this study we have investigated the genotoxic and cytotoxic effects of eluates derived from different types of commercially available dental cements, including glass ionomer cements (GICs) (Ketac Cem/3M ESPE and GC Fuji I/GC Corp), resin-modified glass ionomer cements (RM-GICs) (RelyX Luting/3M ESPE and Vitrebond/3M ESPE) and dual-cure resin cements (RCs) (Variolink II/ Ivoclar-Vivadent and Panavia F 2.0/Kuraray) on normal cultured human lymphocytes. Lymphocyte primary cultures obtained from blood samples of three healthy donors were exposed to serial dilutions of eluates derived from specimens of each material tested. Metaphases were induced with phytohaemagglutinin, collected after 72h treatment by use of colchicine and stained according to the fluorescence plus giemsa (FPG) procedure. Preparations were scored for sister chromatid exchange (SCE) and chromosomal aberrations (CAs), while the proliferation rate index (PRI) was also calculated. Our results show that eluates derived from the RM-GICs and RCs caused severe genotoxic effects by significantly increasing the frequencies of SCEs and CAs in cultures of peripheral blood lymphocytes and by decreasing the relevant PRI values in a dose-dependent manner, whereas the two GICs caused only minor cytogenetic effects. Eluates of the two RM-GICs (Vitrebond and RelyX) were also very cytotoxic, as the first serial dilutions of both materials caused a complete mitotic arrest in lymphocyte cultures. Overall, the degree of genotoxicity and cytotoxicity caused by dental cements decreased as follows: Viterbond>Rely X>Panavia F 2.0>Variolink II>Ketac Cem=GC Fuji I. These results indicate that different types of dental cement differ extensively in their genotoxic and cytotoxic potential and their ability to affect chromosomal integrity, cell-cycle progression, DNA replication and repair. Although these results cannot be directly extrapolated to the clinical situation, the potential occurrence of adverse effects caused by the RM-GICs and RCs tested in this study should be considered when making a clinical decision about dental cements.

Genotoxic effects following exposure to air pollution in street vendors from a high-traffic urban area.

PubMed

Domingues, Érica Prado; Silva, Guilherme Gomes; Oliveira, Andrei Barbassa; Mota, Lorrany Marins; Santos, Vanessa Santana Vieira; de Campos, Edimar Olegário; Pereira, Boscolli Barbosa

2018-03-14

Workers in several occupational environments are exposed to pollutants. Street vendors, for example, typically work in a high-traffic urban environment and are exposed to numerous air pollutants, including genotoxic substances emitted by motor vehicles. This study examined the genotoxic effects of exposure to air pollution. We conducted cytological analyses to assess frequencies of micronucleated (MN) and binucleated (BN) cells in a sample of exfoliated oral mucosa cells. We compared street vendors and control subjects in the city of Uberlândia, Minas Gerais, Brazil, and also collected quantitative information on exposure conditions of all test subjects, including concentrations of particulate matter. We found street vendors to exhibit higher frequencies of MN cells compared to the control group. We evaluated the effects of possible confounding variables on MN frequencies, namely the body mass index (BMI), age, as well as smoking and alcohol habits. Multiple linear regression analysis found no significant effects of any of those variables. Our results suggest that continued exposure to air pollution from traffic represents a major source of genotoxicity and raises concerns regarding disease prevention not only in street vendors but also other groups of people working in urban environments.

3-chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone (MX): toxicological properties and risk assessment in drinking water.

PubMed

Hirose, A; Nishikawa, A; Kinae, N; Hasegawa, R

1999-01-01

MX (3-chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone), one of the byproducts formed during the chlorine disinfection process of drinking water, shows strong mutagenic activity for Salmonella strains in the Ames test. In several countries, the contribution of MX to the total mutagenicity of drinking water is estimated to range from 7% to 67%. To assess the risk of MX for human health, we summarized the toxicological properties of MX and estimated the tolerable daily intake (TDI) or tolerable concentration in drinking water. MX is genotoxic in cultured mammalian cells and causes in vivo DNA damage in several tissues. MX is carcinogenic for rodents in addition to possessing skin and gastric promotion activities. From these toxicological profiles of MX, we estimated the virtual safety dose (VSD) for genotoxic action as 5 ng/kg/d and the TDI for non-genotoxic action of MX as 40 ng/kg/d. We assumed a tolerable MX concentration of 150 ng/L in drinking water. Because of the uncertainty about human genotoxicity, however, and the lack of information on reproductive or developmental toxicity, the estimated tolerable dose level may be provisional.

Vicia root-mirconucleus and sister chromatid exchange assays on the genotoxicity of selenium compounds.

PubMed

Yi, Huilan; Si, Liangyan

2007-06-15

Selenium (Se) is an important metalloid with industrial, environmental, biological and toxicological significance. Excessive selenium in soil and water may contribute to environmental selenium pollution, and affect plant growth and human health. By using Vicia faba micronucleus (MN) and sister chromatid exchange (SCE) tests, possible genotoxicity of sodium selenite and sodium biselenite was evaluated in this study. The results showed that sodium selenite, at concentrations from 0.01 to 10.0mg/L, induced a 1.9-3.9-fold increase in MN frequency and a 1.5-1.6-fold increase in SCE frequency, with a statistically significantly difference from the control (P<0.05 and 0.01, respectively). Sodium selenite also caused mitotic delay and a 15-80% decrease in mitotic indices (MI), but at the lowest concentration (0.005mg/L), it slightly stimulated mitotic activity. Similarly, the frequencies of MN and SCE also increased significantly in sodium biselenite treated samples, with MI decline only at relatively higher effective concentrations. Results of the present study suggest that selenite is genotoxic to V. faba root cells and may be a genotoxic risk to human health.

Genotoxicity profile of erinacine A-enriched Hericium erinaceus mycelium.

PubMed

Li, I-Chen; Chen, Yen-Lien; Chen, Wan-Ping; Lee, Li-Ya; Tsai, Yueh-Ting; Chen, Chin-Chu; Chen, Chin-Shuh

2014-01-01

Hericium erinaceus ( H. erinaceus ) has a long history of usage in traditional Chinese medicine for the treatment of gastric disorders. Recently, it has become a well-established candidate in causing positive brain and nerve health-related activities by inducing nerve growth factor (NGF) from its bioactive ingredient, erinacine A. This active compound, which exists only in fermented mycelium but not in its fruiting body, increases NGF levels in astroglial cells in vitro as well as catecholamine and NGF levels in vivo . With increasing recognition of erinacine A in H. erinaceus (EAHE) mycelium improving neurodegenerative diseases, numerous products are being marketed based on these functional claims. To our knowledge, there have been no reports on the mutagenicity of EAHE prior to this paper. Hence, the present study was undertaken to determine the mutagenicity and genotoxicity effects of EAHE mycelium conducted in three standard battery of tests (reverse mutation, chromosomal aberration, and micronuclei tests) according to the latest guidelines in order to meet all international regulatory requirements and provide information on the safety of this new and promising natural remedy. Our results have indicated that EAHE mycelium did not significantly increase the number of revertant colonies in the bacterial reverse mutation test nor induce higher frequency of aberrations in the chromosome aberration test. Moreover, no statistically significant EAHE mycelium-related increase was observed in the incidence of reticulocytes per 1000 red blood cells and micronucleated reticulocytes per 1000 reticulocytes. In conclusion, the three standard battery of tests suggested that EAHE mycelium was devoid of mutagenicity and genotoxicity in the tested doses and experimental conditions.

Evaluation of in vitro and in vivo genotoxicity of single-walled carbon nanotubes.

PubMed

Kim, Jin Sik; Song, Kyung Seuk; Yu, Il Je

2015-08-01

Single-walled carbon nanotubes (SWCNTs) have extensive potential industrial applications due to their unique physical and chemical properties; yet this also increases the chance of human and environment exposure to SWCNTs. Due to the current lack of hazardous effect information on SWNCTs, a standardized genotoxicity battery test was conducted to clarify the genetic toxicity potential of SWCNTs (diameter: 1-1.2 nm, length: ∼20 μm) according to Organization for Economic Cooperation and Development test guidelines 471 (bacterial reverse mutation test), 473 (in vitro chromosome aberration test), and 474 (in vivo micronuclei test) with a good laboratory practice system. The test results showed that the SWCNTs did not induce significant bacterial reverse mutations at 31.3-500 μg/plate in Salmonella typhimurium strains TA98, TA100, TA1535, and TA1537 or in Escherichia coli strain WP2uvrA, with and without a metabolic activation system. Furthermore, the in vitro chromosome aberration test showed no significant increase in structural or numerical chromosome aberration frequencies at SWCNT dose levels of 12.5-50 μg/ml in the presence and absence of metabolic activation. However, dose-dependent cell growth inhibition was found at all the SWCNT dose levels and statistically significant cytotoxic effects observed at certain concentrations in the presence and absence of metabolic activation. Finally, the SWCNTs did not evoke significant in vivo micronuclei frequencies in the polychromatic erythrocytes of an imprinting control region mice at 25-100 mg/kg. Thus, according to the results of the present study, the SWCNTs were not found to have a genotoxic effect on the in vitro and in vivo test systems. © The Author(s) 2013.

Oxidative stress and genotoxicity induced by ketorolac on the common carp Cyprinus carpio.

PubMed

Galar-Martínez, M; García-Medina, S; Gómez-Olivan, L M; Pérez-Coyotl, I; Mendoza-Monroy, D J; Arrazola-Morgain, R E

2016-09-01

The nonsteroidal anti-inflammatory drug ketorolac is extensively used in the treatment of acute postoperative pain. This pharmaceutical has been found at concentrations of 0.2-60 µg/L in diverse water bodies around the world; however, its effects on aquatic organisms remain unknown. The present study, evaluated the oxidative stress and genotoxicity induced by sublethal concentrations of ketorolac (1 and 60 µg/L) on liver, brain, and blood of the common carp Cyprinus carpio. This toxicant induced oxidative damage (increased lipid peroxidation, hydroperoxide content, and protein carbonyl content) as well as changes in antioxidant status (superoxide dismutase, catalase, and glutathione peroxidase activity) in liver and brain of carp. In blood, ketorolac increased the frequency of micronuclei and is therefore genotoxic for the test species. The effects observed were time and concentration dependent. © 2015 Wiley Periodicals, Inc. Environ Toxicol 31: 1035-1043, 2016. © 2015 Wiley Periodicals, Inc.

Mutagenic and genotoxic potential of direct electric current in Escherichia coli and Salmonella thyphimurium strains.

PubMed

Gomes, Marina das Neves; Cardoso, Janine Simas; Leitão, Alvaro Costa; Quaresma, Carla Holandino

2016-05-01

Direct electric current has several therapeutic uses such as antibacterial and antiprotozoal action, tissues scarring and regeneration, as well as tumor treatment. This method has shown promising results in vivo and in vitro, with significant efficacy and almost no side effects. Considering lack of studies regarding direct electric current mutagenic and/or genotoxic effects, the present work evaluated both aspects by using five different bacterial experimental assays: survival of repair-deficient mutants, Salmonella-histidine reversion mutagenesis (Ames test), forward mutations to rifampicin resistance, phage reactivation, and lysogenic induction. In these experimental conditions, cells were submitted to an approach that allows evaluation of anodic, cathodic, and electro-ionic effects generated by 2 mA of direct electric current, with doses ranging from 0.36 to 3.60 Coulombs. Our results showed these doses did not induce mutagenic or genotoxic effects. © 2016 Wiley Periodicals, Inc.

Absence of toxicity and genotoxicity in an extract of Rubus coriifolius.

PubMed

González-Hernández, S; González-Ramírez, D; Dávila-Rodríguez, M I; Jimenez-Arellanez, A; Meckes-Fischer, M; Said-Fernández, S; Cortés-Gutiérrez, E I

2016-12-02

Rubus coriifolius Focke is a wild plant from the Rosaceae family. It grows in both Guatemala and Mexico. The polar extract of the aerial parts of this plant has antibacterial, anti-inflammatory, and anti-protozoal activities. These properties may explain the traditional use of this plant. In vivo and in vitro assays were used to assess the genotoxic and toxic effects of an ethanol extract of the aerial parts of R. coriifolius. Three groups of rats were orally administered the R. coriifolius extract diluted in ethanol (5%) at doses of 1.89 mg/kg body weight (low dose), 4.72 mg/kg body weight (medium dose), and 9.44 mg/kg body weight (high dose) for 3 weeks. Genotoxic/cytotoxic effects induced by the R. coriifolius ethanol extract were evaluated in vivo by a micronuclei (MN) test in rat's bone marrow cells and in vitro by MN and sister chromatid exchange (SCE) in human lymphocyte cultures. In vivo genotoxicity analyses revealed that the average number of micronucleated polychromatic erythrocytes and the polychromatic erythrocyte/red blood cell ratio at all doses were not significantly different from those of the negative control. In vitro genotoxicity analyses showed that MN, SCE, and proliferative index frequencies in a human lymphocyte cell culture were not significantly different from those of the negative control. These results demonstrate that the ethanol extract of R. coriifolius aerial parts is not toxic or mutagenic (in vitro and in vivo) and does not affect cell proliferation at the concentrations analyzed.

Two dechlorinated chlordecone derivatives formed by in situ chemical reduction are devoid of genotoxicity and mutagenicity and have lower proangiogenic properties compared to the parent compound.

PubMed

Legeay, Samuel; Billat, Pierre-André; Clere, Nicolas; Nesslany, Fabrice; Bristeau, Sébastien; Faure, Sébastien; Mouvet, Christophe

2018-05-01

Chlordecone (CLD) is a chlorinated hydrocarbon insecticide, now classified as a persistent organic pollutant. Several studies have previously reported that chronic exposure to CLD leads to hepatotoxicity, neurotoxicity, raises early child development and pregnancy complications, and increases the risk of liver and prostate cancer. In situ chemical reduction (ISCR) has been identified as a possible way for the remediation of soils contaminated by CLD. In the present study, the objectives were (i) to evaluate the genotoxicity and the mutagenicity of two CLD metabolites formed by ISCR, CLD-5a-hydro, or CLD-5-hydro (5a- or 5- according to CAS nomenclature; CLD-1Cl) and tri-hydroCLD (CLD-3Cl), and (ii) to explore the angiogenic properties of these molecules. Mutagenicity and genotoxicity were investigated using the Ames's technique on Salmonella typhimurium and the in vitro micronucleus micromethod with TK6 human lymphoblastoid cells. The proangiogenic properties were evaluated on the in vitro capillary network formation of human primary endothelial cells. Like CLD, the dechlorinated derivatives of CLD studied were devoid of genotoxic and mutagenic activity. In the assay targeting angiogenic properties, significantly lower microvessel lengths formed by endothelial cells were observed for the CLD-3Cl-treated cells compared to the CLD-treated cells for two of the three tested concentrations. These results suggest that dechlorinated CLD derivatives are devoid of mutagenicity and genotoxicity and have lower proangiogenic properties than CLD.

Mutagenicity and genotoxicity of coal fly ash water leachate

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chakraborty, R.; Mukherjee, A.

2009-03-15

Fly ash is a by-product of coal-fired electricity generation plants. The prevalent practice of disposal is as slurry of ash and water to storage or ash ponds located near power stations. This has lain to waste thousands of hectares of land all over the world. Since leaching is often the cause of off-site contamination and pathway of introduction into the human environment, a study on the genotoxic effects of fly ash leachate is essential. Leachate prepared from the fly ash sample was analyzed for metal content, and tested for mutagenicity and genotoxicity. Analyses of metals show predominance of the metalsmore » - sodium, silicon, potassium, calcium, magnesium, iron, manganese, zinc, and sulphate. The Ames Salmonella mutagenicity assay, a short-term bacterial reverse mutation assay, was conducted on two-tester strains of Salmonella typhimurium strains TA97a and TA102. For genotoxicity, the alkaline version of comet assay on fly ash leachate was carried in vitro on human blood cells and in vivo on Nicotiana plants. The leachate was directly mutagenic and induced significantconcentration-dependent increases in DNA damage in whole blood cells, lymphocytes, and in Nicotiana plants. The comet parameters show increases in tail DNA percentage (%), tail length (mu m), and olive tail moment (arbitrary units). Our results indicate that leachate from fly ash dumpsites has the genotoxic potential and may lead to adverse effects on vegetation and on the health of exposed human populations.« less

Antioxidant and antigenotoxic potencies of Sempervivum armenum on human lymphocytes in vitro.

PubMed

Sunar, Serap; Anar, Mustafa; Sengul, Meryem; Agar, Guleray

2016-12-01

In this research, the genotoxic and antigenotoxic effects of methanol extract of Sempervivum armenum (MSA) were studied using micronucleus (MN) test and sister chromatid exchange (SCE) test systems in cultured human peripheral blood cells. According to the SCE and MN tests results, MSA reduced the genotoxic effects of aflatoxin B 1 . In order to explain the reason for the antigenotoxic effects of MSA, antioxidants levels were determined. Cotreatments of 5, 10, 20 mg/mL concentrations of MSA with aflatoxin B 1 decreased the frequencies of SCE, MN and the malondialdehyde level and increased the amount of superoxide dismutase, glutathione and glutathione peroxidase which were decreased by aflatoxin. The results of this experiment showed that MSA has strong antioxidative and antigenotoxic effects and this antigenotoxic activities of MSA can be due to the antioxidant activities.

Predicting the carcinogenicity of chemicals with alternative approaches: recent advances.

PubMed

Benigni, Romualdo

2014-09-01

Alternative approaches to the rodent bioassay are necessary for early identification of problematic drugs and biocides during the development process, and are the only practicable tool for assessing environmental chemicals with no or adequate safety documentation. This review informs on: i) the traditional prescreening through genotoxicity testing; ii) an integrative approach that assesses DNA-reactivity and ability to disorganize tissues; iii) new applications of omics technologies (ToxCast/Tox21 project); iv) a pragmatic approach aimed at filling data gaps by intrapolating/extrapolating from similar chemicals (read-across, category formation). The review also approaches the issue of the concerns about false-positive and false-negative results that prevents a wider acceptance and use of alternatives. The review addresses strengths and limitations of various proposals, and concludes on the need of differential approaches to the issue of false negatives and false positives. False negatives can be eliminated or reduced below the variability of the animal assay with conservative quantitative structure-activity relationships or in vitro tests; false positives can be cleared with ad hoc mechanistically based follow-ups. This framework can permit a reduction of animal testing and a better protection of human health.

First cytotoxic, genotoxic, and antigenotoxic assessment of Euterpe oleracea fruit oil (açaí) in cultured human cells.

PubMed

Marques, E S; Tsuboy, M S F; Carvalho, J C T; Rosa, P C P; Perazzo, F F; Gaivão, I O M; Maistro, E L

2017-08-17

Euterpe oleracea Mart., popularly known as "açaí", is a tropical fruit from the Amazon region where it has considerable economic importance. Açaí has been used as food and for several medicinal purposes. Despite the widespread use of this fruit, there is a lack of data regarding the safety of using this fruit oil exclusively. Therefore, we evaluated the in vitro cytotoxic, genotoxic, and antigenotoxic effects of E. oleracea fruit oil (EOO) in cultured human lymphocytes (non-metabolizing cells) and HepG2 cell line (human hepatoma) (metabolizing cells) by using MTT, comet, and micronucleus assays. A wide range of EOO concentrations was tested with a preliminary MTT assay, which allowed selecting five concentrations for comet and micronucleus assays: 2.5, 10, 100, 500, and 1000 µg/mL. The results showed that none of the EOO tested concentrations presented cytotoxic effects. The genotoxic assessment revealed an absence of significant DNA and chromosome damage in human lymphocytes and HepG2 cells but did not show chemoprotection against the DNA damage induced by methyl methanesulfonate and benzo[a]pyrene, used as DNA-damaging agents.

JaCVAM-organized international validation study of the in vivo rodent alkaline comet assay for the detection of genotoxic carcinogens: I. Summary of pre-validation study results.

PubMed

Uno, Yoshifumi; Kojima, Hajime; Omori, Takashi; Corvi, Raffaella; Honma, Masamistu; Schechtman, Leonard M; Tice, Raymond R; Burlinson, Brian; Escobar, Patricia A; Kraynak, Andrew R; Nakagawa, Yuzuki; Nakajima, Madoka; Pant, Kamala; Asano, Norihide; Lovell, David; Morita, Takeshi; Ohno, Yasuo; Hayashi, Makoto

2015-07-01

The in vivo rodent alkaline comet assay (comet assay) is used internationally to investigate the in vivo genotoxic potential of test chemicals. This assay, however, has not previously been formally validated. The Japanese Center for the Validation of Alternative Methods (JaCVAM), with the cooperation of the U.S. NTP Interagency Center for the Evaluation of Alternative Toxicological Methods (NICEATM)/the Interagency Coordinating Committee on the Validation of Alternative Methods (ICCVAM), the European Centre for the Validation of Alternative Methods (ECVAM), and the Japanese Environmental Mutagen Society/Mammalian Mutagenesis Study Group (JEMS/MMS), organized an international validation study to evaluate the reliability and relevance of the assay for identifying genotoxic carcinogens, using liver and stomach as target organs. The ultimate goal of this validation effort was to establish an Organisation for Economic Co-operation and Development (OECD) test guideline. The purpose of the pre-validation studies (i.e., Phase 1 through 3), conducted in four or five laboratories with extensive comet assay experience, was to optimize the protocol to be used during the definitive validation study. Copyright © 2015 Elsevier B.V. All rights reserved.

Evaluation of emission toxicity of urban bus engines: compressed natural gas and comparison with liquid fuels.

PubMed

Turrio-Baldassarri, Luigi; Battistelli, Chiara Laura; Conti, Luigi; Crebelli, Riccardo; De Berardis, Barbara; Iamiceli, Anna Laura; Gambino, Michele; Iannaccone, Sabato

2006-02-15

Emissions from a spark-ignition (SI) heavy-duty (HD) urban bus engine with a three-way catalyst (TWC), fuelled with compressed natural gas (CNG), were chemically analyzed and tested for genotoxicity. The results were compared with those obtained in a previous study on an equivalent diesel engine, fuelled with diesel oil (D) and a blend of the same with 20% vegetable oil (B20). Experimental procedures were identical, so that emission levels of the CNG engine were exactly comparable to the ones of the diesel engine. The experimental design was focused on carcinogenic compounds and genotoxic activity of exhausts. The results obtained show that the SI CNG engine emissions, with respect to the diesel engine fuelled with D, were nearly 50 times lower for carcinogenic polycyclic aromatic hydrocarbons (PAHs), 20 times lower for formaldehyde, and more than 30 times lower for particulate matter (PM). A 20-30 fold reduction of genotoxic activity was estimated from tests performed. A very high reduction of nitrogen oxides (NO(X)) was also measured. The impact of diesel powered transport on urban air quality, and the potential benefits deriving from the use of CNG for public transport, are discussed.

IWGT report on quantitative approaches to genotoxicity risk ...

EPA Pesticide Factsheets

This is the second of two reports from the International Workshops on Genotoxicity Testing (IWGT) Working Group on Quantitative Approaches to Genetic Toxicology Risk Assessment (the QWG). The first report summarized the discussions and recommendations of the QWG related to the need for quantitative dose–response analysis of genetic toxicology data, the existence and appropriate evaluation of threshold responses, and methods to analyze exposure-response relationships and derive points of departure (PoDs) from which acceptable exposure levels could be determined. This report summarizes the QWG discussions and recommendations regarding appropriate approaches to evaluate exposure-related risks of genotoxic damage, including extrapolation below identified PoDs and across test systems and species. Recommendations include the selection of appropriate genetic endpoints and target tissues, uncertainty factors and extrapolation methods to be considered, the importance and use of information on mode of action, toxicokinetics, metabolism, and exposure biomarkers when using quantitative exposure-response data to determine acceptable exposure levels in human populations or to assess the risk associated with known or anticipated exposures. The empirical relationship between genetic damage (mutation and chromosomal aberration) and cancer in animal models was also examined. It was concluded that there is a general correlation between cancer induction and mutagenic and/or clast

Chronic genetic damages in Geophagus brasiliensis exposed to anthropic impact in estuarine lakes at Santa Catarina coast--southern of Brazil.

PubMed

Benincá, Cristiane; Ramsdorf, Wanessa; Vicari, Taynah; de Oliveira Ribeiro, Ciro A; de Almeida, Marina I; Silva de Assis, Helena C; Cestari, Marta Margarete

2012-04-01

Biological monitoring through animals exposed to pollutants using biomarkers provides a promising tool for the identification of pollutants that may cause damage to human health and/or to sustainability of ecosystems. The effects of pollutants in fish tissues are important tools to understand the impact of human activities in natural ecosystems. The aim of this work was to study the water quality of two estuarine lakes in Santa Catarina, Brazil (Camacho Lake and Santa Marta Lake). Geophagus brasiliensis is a species widely distributed in Brazil and was used in this work. Comet assays in peripheral red blood and kidney cells, micronucleus tests in peripheral red blood cells, measurements of acetylcholinesterase activity in axial muscle and histopathological analysis of liver were used as biomarkers. Three sampling campaigns were undertaken in November 2004, June 2005 and November 2005. Thirty adult animals were sampled from each of three different sites (P1--Santa Marta Lake, P2 and P3--Camacho Lake). A negative control was sampled in a non-polluted site at Costa Ecological Park, Paraná. The positive control for genotoxicity was obtained by treating animals with copper sulphate. The results showed that both studied lakes are impacted by potential genotoxic substances. Severe lesions in liver of G. brasiliensis were also observed. The inhibition of acetylcholinesterase activity suggests the presence of pesticides or metals in the studied sites. This work shows that the water quality of Santa Marta and Camacho Lakes have been compromised and further control source of pollutants into these ecosystems is required.

Genotoxicity of TiO2 nanoparticles assessed by mini-gel comet assay and micronucleus scoring with flow cytometry.

PubMed

Di Bucchianico, Sebastiano; Cappellini, Francesca; Le Bihanic, Florane; Zhang, Yuning; Dreij, Kristian; Karlsson, Hanna L

2017-01-01

The widespread production and use of nanoparticles calls for faster and more reliable methods to assess their safety. The main aim of this study was to investigate the genotoxicity of three reference TiO 2 nanomaterials (NM) within the frame of the FP7-NANoREG project, with a particular focus on testing the applicability of mini-gel comet assay and micronucleus (MN) scoring by flow cytometry. BEAS-2B cells cultured under serum-free conditions were exposed to NM100 (anatase, 50-150nm), NM101 (anatase, 5-8nm) and NM103 (rutile, 20-28nm) for 3, 24 or 48h mainly at concentrations 1-30 μg/ml. In the mini-gel comet assay (eight gels per slide), we included analysis of (i) DNA strand breaks, (ii) oxidised bases (Fpg-sensitive sites) and (iii) light-induced DNA damage due to photocatalytic activity. Furthermore, MN assays were used and we compared the results of more high-throughput MN scoring with flow cytometry to that of cytokinesis-block MN cytome assay scored manually using a microscope. Various methods were used to assess cytotoxic effects and the results showed in general no or low effects at the doses tested. A weak genotoxic effect of the tested TiO 2 materials was observed with an induction of oxidised bases for all three materials of which NM100 was the most potent. When the comet slides were briefly exposed to lab light, a clear induction of DNA strand breaks was observed for the anatase materials, but not for the rutile. This highlights the risk of false positives when testing photocatalytically active materials if light is not properly avoided. A slight increase in MN formation for NM103 was observed in the different MN assays at the lower doses tested (1 and 5 μg/ml). We conclude that mini-gel comet assay and MN scoring using flow cytometry successfully can be used to efficiently study cytotoxic and genotoxic properties of nanoparticles. © The Author 2016. Published by Oxford University Press on behalf of the UK Environmental Mutagen Society.

Genotoxicity of TiO2 nanoparticles assessed by mini-gel comet assay and micronucleus scoring with flow cytometry

PubMed Central

Di Bucchianico, Sebastiano; Cappellini, Francesca; Le Bihanic, Florane; Zhang, Yuning; Dreij, Kristian; Karlsson, Hanna L.

2017-01-01

The widespread production and use of nanoparticles calls for faster and more reliable methods to assess their safety. The main aim of this study was to investigate the genotoxicity of three reference TiO2 nanomaterials (NM) within the frame of the FP7-NANoREG project, with a particular focus on testing the applicability of mini-gel comet assay and micronucleus (MN) scoring by flow cytometry. BEAS-2B cells cultured under serum-free conditions were exposed to NM100 (anatase, 50–150nm), NM101 (anatase, 5–8nm) and NM103 (rutile, 20–28nm) for 3, 24 or 48h mainly at concentrations 1–30 μg/ml. In the mini-gel comet assay (eight gels per slide), we included analysis of (i) DNA strand breaks, (ii) oxidised bases (Fpg-sensitive sites) and (iii) light-induced DNA damage due to photocatalytic activity. Furthermore, MN assays were used and we compared the results of more high-throughput MN scoring with flow cytometry to that of cytokinesis-block MN cytome assay scored manually using a microscope. Various methods were used to assess cytotoxic effects and the results showed in general no or low effects at the doses tested. A weak genotoxic effect of the tested TiO2 materials was observed with an induction of oxidised bases for all three materials of which NM100 was the most potent. When the comet slides were briefly exposed to lab light, a clear induction of DNA strand breaks was observed for the anatase materials, but not for the rutile. This highlights the risk of false positives when testing photocatalytically active materials if light is not properly avoided. A slight increase in MN formation for NM103 was observed in the different MN assays at the lower doses tested (1 and 5 μg/ml). We conclude that mini-gel comet assay and MN scoring using flow cytometry successfully can be used to efficiently study cytotoxic and genotoxic properties of nanoparticles. PMID:27382040

A three-dimensional in vitro HepG2 cells liver spheroid model for genotoxicity studies.

PubMed

Shah, Ume-Kulsoom; Mallia, Jefferson de Oliveira; Singh, Neenu; Chapman, Katherine E; Doak, Shareen H; Jenkins, Gareth J S

2018-01-01

The liver's role in metabolism of chemicals makes it an appropriate tissue for toxicity testing. Current testing protocols, such as animal testing and two-dimensional liver cell systems, offer limited resemblance to in vivo liver cell behaviour, in terms of gene expression profiles and metabolic competence; thus, they do not always accurately predict human toxicology. In vitro three-dimensional liver cell models offer an attractive alternative. This study reports on the development of a 3D liver model, using HepG2 cells, by a hanging-drop technique, with a focus on evaluating spheroid growth characteristics and suitability for genotoxicity testing. The cytokinesis-blocked micronucleus assay protocol was adapted to enable micronucleus (MN) detection in the 3D spheroid models. This involved evaluating the difference between hanging vs non-hanging drop positions for dosing of the test agents and comparison of automated Metafer scoring with manual scoring for MN detection in HepG2 spheroids. The initial seeding density, used for all experiments, was 5000 cells/20 μl drop hanging spheroids, harvested on day 4, with >75% cell viability. Albumin secretion (7.8 g/l) and both CYP1A1 and CYP1A2 gene expression were highest in the 3D environment at day 4. Exposure to metabolically activated genotoxicants for 24 h resulted in a 6-fold increase in CYP1A1 enzyme activity (3 μM B[a]P) and a 30-fold increase in CYP1A2 enzyme activity (5 μM PhIP) in 3D hanging spheroids. MN inductions in response to B[a]P or PhIP were 2-fold and 3-fold, respectively, and were greater in 3D hanging spheroids than in 2D format, showing that hanging spheroids are more sensitive to genotoxic agents. HepG2 hanging-drop spheroids are an exciting new alternative system for genotoxicity studies, due to their improved structural and physiological properties, relative to 2D cultures. Copyright © 2017 Elsevier B.V. All rights reserved.

Evaluation of the genotoxic potential of soil contaminated with mineral coal tailings on snail Helix aspersa.

PubMed

de Souza, Melissa Rosa; da Silva, Fernanda Rabaioli; de Souza, Claudia Telles; Niekraszewicz, Liana; Dias, Johnny Ferraz; Premoli, Suziane; Corrêa, Dione Silva; Soares, Mariana do Couto; Marroni, Norma Possa; Morgam-Martins, Maria Isabel; da Silva, Juliana

2015-11-01

Coal remains an important source of energy, although the fuel is a greater environmental pollutant. Coal is a mixture of several chemicals, especially inorganic elements and polycyclic aromatic hydrocarbons (PAH). Many of these compounds have mutagenic and carcinogenic effects on organisms exposed to this mineral. In the town of Charqueadas (Brazil), the tailings from mining were used for landfill in the lower areas of the town, and the consequence is the formation of large deposits of this material. The purpose of this study was to evaluate the genotoxic potential of soil samples contaminated by coal waste in different sites at Charqueadas, using the land snail Helix aspersa as a biomonitor organism. Thirty terrestrial snails were exposed to different treatments: 20 were exposed to the soil from two different sites in Charqueadas (site 1 and 2; 10 in each group) and 10 non-exposed (control group). Hemolymph cells were collected after 24h, 5days and 7days of exposure and comet assay, micronucleus test, oxidative stress tests were performed. Furthermore, this study quantified the inorganic elements present in soil samples by the PIXE technique and polycyclic aromatic hydrocarbons (PAH) by HPLC. This evaluation shows that, in general, soils from sites in Charqueadas, demonstrated a genotoxic effect associated with increased oxidative stress, inorganic and PAH content. These results demonstrate that the coal pyrite tailings from Charqueadas are potentially genotoxic and that H. aspersa is confirmed to be a sensitive instrument for risk assessment of environmental pollution. Copyright © 2015 Elsevier Ltd. All rights reserved.

Genetic damage of organic matter in the Brazilian Amazon: a comparative study between intense and moderate biomass burning.

PubMed

de Oliveira Alves, Nilmara; de Souza Hacon, Sandra; de Oliveira Galvão, Marcos Felipe; Simões Peixotoc, Milena; Artaxo, Paulo; de Castro Vasconcellos, Pérola; de Medeiros, Silvia Regina Batistuzzo

2014-04-01

The biomass burning that occurs in the Amazon region has an adverse effect on environmental and human health. However, in this region, there are limited studies linking atmospheric pollution and genetic damage. We conducted a comparative study during intense and moderate biomass burning periods focusing on the genetic damage and physicochemical analyses of the particulate matter (PM). PM and black carbon (BC) were determined; organic compounds were identified and quantified using gas chromatography with flame ionization detection, the cyto-genotoxicity test was performed using two bioassays: cytokinesis-block micronucleus (CBMN) in A549 cells and Tradescantia pallida micronucleus (Trad-MCN) assay. The PM10 concentrations were lower than the World Health Organization air quality standard for 24h. The n-alkanes analyses indicate anthropogenic and biogenic influences during intense and moderate biomass burning periods, respectively. Retene was identified as the most abundant polycyclic aromatic hydrocarbon during both sampling periods. Carcinogenic and mutagenic compounds were identified. The genotoxic analysis through CBMN and Trad-MCN tests showed that the frequency MCN from the intense burning period is significantly higher compared to moderate burning period. This is the first study using human alveolar cells to show the genotoxic effects of organic PM from biomass burning samples collected in Amazon region. The genotoxicity of PM can be associated with the presence of several mutagenic and carcinogenic compounds, mainly benzo[a]pyrene. These findings have potential implications for the development of pollution abatement strategies and can minimize negative impact on health. Copyright © 2014 Elsevier Inc. All rights reserved.

DNA damage and micronuclei in parthenogenetic and bisexual Darevskia rock lizards from the areas with different levels of soil pollution.

PubMed

Simonyan, Anna; Hovhannisyan, Galina; Sargsyan, Anzhela; Arakelyan, Marine; Minasyan, Seyran; Aroutiounian, Rouben

2018-06-15

Natural species are widely used as indicator organisms to estimate of the impact of environmental pollution. Here we present the results of first study of a reliability of parthenogenetic Darevskia аrmeniaca and bisexual Darevskia raddei rock lizards as sentinels for monitoring of environmental genotoxicity. The comet assay and micronucleus test were applied to the lizards sampled in six areas in Armenia and Artsakh with different levels of soil contamination. The results obtained showed a clear relationship between the pollution level of lizards' habitats and the frequency of DNA damage in the comet assay. Low baseline frequency of micronuclei in D. аrmeniaca and D. raddei, however, makes this parameter ineffective for environmental genotoxicity evaluation. The parthenogenetic lizards D. аrmeniaca showed higher sensitivity toward genotoxic pollutions compared with bisexual D. raddei living in the same environment. The correlations between soil content of heavy metals Cr, Cu, Zn, Mo, Pb and DNA damage in D. аrmeniaca and between Cu, As, Mo, Pb and DNA damage in D. raddei were revealed. Overall, the lizards D. raddei and D. аrmeniaca appeared to be sensitive species in detecting soil pollution in natural environment. The application of the comet assay in Darevskia lizard species can be considered as a more appropriate method than a micronucleus test. The use of parthenogenetic lizards D. аrmeniaca as bioindicator will permit to assess the environmental genotoxicity independent of the genetic polymorphism of bisexual species. Copyright © 2018. Published by Elsevier Inc.

Risk assessment of carcinogens in food.

PubMed

Barlow, Susan; Schlatter, Josef

2010-03-01

Approaches for the risk assessment of carcinogens in food have evolved as scientific knowledge has advanced. Early methods allowed little more than hazard identification and an indication of carcinogenic potency. Evaluation of the modes of action of carcinogens and their broad division into genotoxic and epigenetic (non-genotoxic, non-DNA reactive) carcinogens have played an increasing role in determining the approach followed and provide possibilities for more detailed risk characterisation, including provision of quantitative estimates of risk. Reliance on experimental animal data for the majority of risk assessments and the fact that human exposures to dietary carcinogens are often orders of magnitude below doses used in experimental studies has provided a fertile ground for discussion and diverging views on the most appropriate way to offer risk assessment advice. Approaches used by national and international bodies differ, with some offering numerical estimates of potential risks to human health, while others express considerable reservations about the validity of quantitative approaches requiring extrapolation of dose-response data below the observed range and instead offer qualitative advice. Recognising that qualitative advice alone does not provide risk managers with information on which to prioritise the need for risk management actions, a "margin of exposure" approach for substances that are both genotoxic and carcinogenic has been developed, which is now being used by the World Health Organization and the European Food Safety Authority. This review describes the evolution of risk assessment advice on carcinogens and discusses examples of ways in which carcinogens in food have been assessed in Europe.

Genotoxic potential of montmorillonite clay mineral and alteration in the expression of genes involved in toxicity mechanisms in the human hepatoma cell line HepG2.

PubMed

Maisanaba, Sara; Hercog, Klara; Filipic, Metka; Jos, Ángeles; Zegura, Bojana

2016-03-05

Montmorillonite, also known as Cloisite(®)Na(+) (CNa(+)), is a natural clay with a wide range of well-documented and novel applications, such as pharmaceutical products or food packaging. Although considered a low toxic product, the expected increased exposure to CNa(+) arises concern on the potential consequences on human and environmental health especially as its genotoxicity has scarcely been investigated so far. Thus, we investigated, for the first time, the influence of non-cytotoxic concentrations of CNa(+) (15.65, 31.25 and 62.5 μg/mL) on genomic instability of human hepatoma cell line (HepG2) by determining the formation of micronuclei (MNi), nucleoplasmic bridges (NPBs) and nuclear buds (NBUDs) with the Cytokinesis block micronucleus cytome assay. Further on we studied the influence of CNa(+) on the expression of several genes involved in toxicity mechanisms using the real-time quantitative PCR. The results showed that CNa(+) increased the number of MNi, while the numbers of NBUDs and NPBs were not affected. In addition it deregulated genes in all the groups studied, mainly after longer time of exposure. These findings provide the evidence that CNa(+) is potentially genotoxic. Therefore further studies that will elucidate the molecular mechanisms involved in toxic activity of CNa(+) are needed for hazard identification and human safety assessment. Copyright © 2015 Elsevier B.V. All rights reserved.

GENETIC ACTIVITY PROFILES AND PATTERN RECOGNITION IN TEST BATTERY SELECTION (JOURNAL VERSION)

EPA Science Inventory

Computer-generated genetic activity profiles and pairwise matching procedures may aid in the selection of the most appropriate short-term bioassays to be used in test batteries for the evaluation of the genotoxicity of a given chemical or group of chemicals. Selection of test bat...

Insecticidal and genotoxic activity of Psoralea corylifolia Linn. (Fabaceae) against Culex quinquefasciatus Say, 1823

PubMed Central

2013-01-01

Background Indiscriminate use of synthetic insecticides to eradicate mosquitoes has caused physiological resistance. Plants provide a reservoir of biochemical compounds; among these compounds some have inhibitory effect on mosquitoes. In the present study the larvicidal, adulticidal and genotoxic activity of essential oil of Psoralea corylifolia Linn. against Culex quinquefasciatus Say was explored. Methods Essential oil was isolated from the seeds of P. corylifolia Linn. Larvicidal and adulticidal bioassay of Cx. quinquefasciatus was carried out by WHO method. Genotoxic activity of samples was determined by comet assay. Identification of different compounds was carried out by gas chromatography- mass spectrometry analysis. Results LC50 and LC90 values of essential oil were 63.38±6.30 and 99.02±16.63 ppm, respectively against Cx. quinquefasciatus larvae. The LD50 and LD90 values were 0.057±0.007 and 0.109±0.014 mg/cm2 respectively against adult Cx. quinquefasciatus,. Genotoxicity of adults was determined at 0.034 and 0.069 mg/cm2. The mean comet tail length was 6.2548±0.754 μm and 8.47±0.931 μm and the respective DNA damage was significant i.e. 6.713% and 8.864% in comparison to controls. GCMS analysis of essential oil revealed 20 compounds. The major eight compounds were caryophyllene oxide (40.79%), phenol,4-(3,7-dimethyl-3-ethenylocta-1,6-dienyl) (20.78%), caryophyllene (17.84%), α-humulene (2.15%), (+)- aromadendrene (1.57%), naphthalene, 1,2,3,4-tetra hydro-1,6-dimethyle-4-(1-methyl)-, (1S-cis) (1.53%), trans- caryophyllene (0.75%), and methyl hexadecanoate (0.67%). Conclusion Essential oil obtained from the seeds of P. corylifolia showed potent toxicity against larvae and adult Cx. quinquefasciatus. The present work revealed that the essential oil of P. corylifolia could be used as environmentally sound larvicidal and adulticidal agent for mosquito control. PMID:23379981

Using Drosophila melanogaster as a Model for Genotoxic Chemical Mutational Studies with a New Program, SnpSift

PubMed Central

Cingolani, Pablo; Patel, Viral M.; Coon, Melissa; Nguyen, Tung; Land, Susan J.; Ruden, Douglas M.; Lu, Xiangyi

2012-01-01

This paper describes a new program SnpSift for filtering differential DNA sequence variants between two or more experimental genomes after genotoxic chemical exposure. Here, we illustrate how SnpSift can be used to identify candidate phenotype-relevant variants including single nucleotide polymorphisms, multiple nucleotide polymorphisms, insertions, and deletions (InDels) in mutant strains isolated from genome-wide chemical mutagenesis of Drosophila melanogaster. First, the genomes of two independently isolated mutant fly strains that are allelic for a novel recessive male-sterile locus generated by genotoxic chemical exposure were sequenced using the Illumina next-generation DNA sequencer to obtain 20- to 29-fold coverage of the euchromatic sequences. The sequencing reads were processed and variants were called using standard bioinformatic tools. Next, SnpEff was used to annotate all sequence variants and their potential mutational effects on associated genes. Then, SnpSift was used to filter and select differential variants that potentially disrupt a common gene in the two allelic mutant strains. The potential causative DNA lesions were partially validated by capillary sequencing of polymerase chain reaction-amplified DNA in the genetic interval as defined by meiotic mapping and deletions that remove defined regions of the chromosome. Of the five candidate genes located in the genetic interval, the Pka-like gene CG12069 was found to carry a separate pre-mature stop codon mutation in each of the two allelic mutants whereas the other four candidate genes within the interval have wild-type sequences. The Pka-like gene is therefore a strong candidate gene for the male-sterile locus. These results demonstrate that combining SnpEff and SnpSift can expedite the identification of candidate phenotype-causative mutations in chemically mutagenized Drosophila strains. This technique can also be used to characterize the variety of mutations generated by genotoxic chemicals. PMID:22435069

Structure, mechanical characteristics and in vitro degradation, cytotoxicity, genotoxicity and mutagenicity of novel biodegradable Zn-Mg alloys.

PubMed

Kubásek, J; Vojtěch, D; Jablonská, E; Pospíšilová, I; Lipov, J; Ruml, T

2016-01-01

Zn-(0-1.6)Mg (in wt.%) alloys were prepared by hot extrusion at 300 °C. The structure, mechanical properties and in vitro biocompatibility of the alloys were investigated. The hot-extruded magnesium-based WE43 alloy was used as a control. Mechanical properties were evaluated by hardness, compressive and tensile testing. The cytotoxicity, genotoxicity (comet assay) and mutagenicity (Ames test) of the alloy extracts and ZnCl2 solutions were evaluated with the use of murine fibroblasts L929 and human osteosarcoma cell line U-2 OS. The microstructure of the Zn alloys consisted of recrystallized Zn grains of 12 μm in size and fine Mg2Zn11 particles arranged parallel to the hot extrusion direction. Mechanical tests revealed that the hardness and strength increased with increasing Mg concentration. The Zn-0.8 Mg alloys showed the best combination of tensile mechanical properties (tensile yield strength of 203 MPa, ultimate tensile strength of 301 MPa and elongation of 15%). At higher Mg concentrations the plasticity of Zn-Mg alloys was deteriorated. Cytotoxicity tests with alloy extracts and ZnCl2 solutions proved the maximum safe Zn(2+) concentrations of 120 μM and 80 μM for the U-2 OS and L929 cell lines, respectively. Ames test with extracts of alloys indicated that the extracts were not mutagenic. The comet assay demonstrated that 1-day extracts of alloys were not genotoxic for U-2 OS and L929 cell lines after 1-day incubation. Copyright © 2015 Elsevier B.V. All rights reserved.

Comprehensive evaluation of the flavonol anti-oxidants, alpha-glycosyl isoquercitrin and isoquercitrin, for genotoxic potential.

PubMed

Hobbs, Cheryl A; Koyanagi, Mihoko; Swartz, Carol; Davis, Jeffrey; Kasamoto, Sawako; Maronpot, Robert; Recio, Leslie; Hayashi, Shim-Mo

2018-03-01

Quercetin and its glycosides possess potential benefits to human health. Several flavonols are available to consumers as dietary supplements, promoted as anti-oxidants; however, incorporation of natural quercetin glycosides into food and beverage products has been limited by poor miscibility in water. Enzymatic conjugation of multiple glucose moieties to isoquercitrin to produce alpha-glycosyl isoquercitrin (AGIQ) enhances solubility and bioavailability. AGIQ is used in Japan as a food additive and has been granted generally recognized as safe (GRAS) status. However, although substantial genotoxicity data exist for quercetin, there is very little available data for AGIQ and isoquercitrin. To support expanded global marketing of food products containing AGIQ, comprehensive testing of genotoxic potential of AGIQ and isoquercitrin was conducted according to current regulatory test guidelines. Both chemicals tested positive in bacterial reverse mutation assays, and exposure to isoquercitrin resulted in chromosomal aberrations in CHO-WBL cells. All other in vitro mammalian micronucleus and chromosomal aberration assays, micronucleus and comet assays in male and female B6C3F1 mice and Sprague Dawley rats, and Muta™ Mouse mutation assays evaluating multiple potential target tissues, were negative for both chemicals. These results supplement existing toxicity data to further support the safe use of AGIQ in food and beverage products. Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.

Analysis of genotoxic activity of ketamine and rocuronium bromide using the somatic mutation and recombination test in Drosophila melanogaster.

PubMed

Koksal, Pakize Muge; Gürbüzel, Mehmet

2015-03-01

The present study evaluated the mutagenic and recombinogenic effects of two commonly used anesthetic agents, ketamine and rocuronium bromide, in medicine using the wing somatic mutation and recombination test (SMART) in Drosophila. The standard (ST) cross and the high-bioactivation (HB) cross with high sensitivity to procarcinogens and promutagens were used. The SMART test is based on the loss of heterozygosity, which occurs via various mechanisms, such as chromosome loss and deletion, half-translocation, mitotic recombination, mutation, and non-disjunction. Genetic alterations occurring in the somatic cells of the wing's imaginal discs result in mutant clones in the wing blade. Three-day-old trans-heterozygous larvae with two recessive markers, multiple wing hairs (mwh) and flare (flr(3)), were treated with ketamine and rocuronium bromide. Analysis of the ST cross indicated that ketamine exhibited genotoxicity activity and that this activity was particularly dependent on homologous mitotic recombination at concentrations of 250 μg/ml and above. Rocuronium bromide did not exert mutagenic and/or recombinogenic effects. In the HB cross, ketamine at a concentration of 1000 μg/ml and rocuronium bromide at all concentrations, with the exception of 250 μg/ml (inconclusive), exerted genotoxic effects, which could also be associated with the increase in mitotic recombination. Copyright © 2015 Elsevier B.V. All rights reserved.

Assessment of the genotoxic/clastogenic potential of coumarin derivative 6,7-dihydroxycoumarin (aesculetin) in multiple mouse organs.

PubMed

Marques, Eduardo de Souza; Salles, Daiane Bernardoni; Maistro, Edson Luis

2015-01-01

6,7-Dihydroxycoumarin (6,7-HC) (aesculetin) is a natural and synthetic coumarin derivative of great interest for use by humans due to their potent antioxidant properties. Considering that there are no reports that assess the in vivo genetic toxicity of 6,7-HC, the aim of the present study was to investigate its genotoxic potential in terms of DNA damage in peripheral blood, liver, bone marrow and testicular cells of Swiss albino mice by the comet assay, and its clastogenic/aneugenic potential in bone marrow cells using the micronucleus test. In addition, the ability of 6,7-HC to modulate the genotoxic effects induced by doxorubicin (DXR) was also preliminarily evaluated. Cytotoxicity was assessed by scoring polychromatic (PCE) and normochromatic (NCE) erythrocytes' ratio. The test compound was administered orally at doses of 25, 50 and 500 mg kg -1 isolated and also simultaneously to DXR (80 mg kg -1 ). The results showed that 6,7-HC did not induce significant DNA damage in any of the analyzed cells, and also did not show any significant increase in micronucleated PCE at the three tested doses. The PCE/NCE ratio indicated no cytotoxicity. Moreover, the extent of DNA damage induced by DXR decreased significantly only in peripheral blood and testicular cells, and only at the lowest dose of 6,7-HC.

The BIOSAFEPAPER project for in vitro toxicity assessments: preparation, detailed chemical characterisation and testing of extracts from paper and board samples.

PubMed

Bradley, E L; Honkalampi-Hämäläinen, U; Weber, A; Andersson, M A; Bertaud, F; Castle, L; Dahlman, O; Hakulinen, P; Hoornstra, D; Lhuguenot, J-C; Mäki-Paakkanen, J; Salkinoja-Salonen, M; Speck, D R; Severin, I; Stammati, A; Turco, L; Zucco, F; von Wright, A

2008-07-01

Nineteen food contact papers and boards and one non-food contact board were extracted following test protocols developed within European Union funded project BIOSAFEPAPER. The extraction media were either hot or cold water, 95% ethanol or Tenax, according to the end use of the sample. The extractable dry matter content of the samples varied from 1200 to 11,800 mg/kg (0.8-35.5 mg/dm2). According to GC-MS the main substances extracted into water were pulp-derived natural products such as fatty acids, resin acids, natural wood sterols and alkanols. Substances extracted into ethanol particularly, were diisopropylnaphthalenes, alkanes and phthalic acid esters. The non-food contact board showed the greatest number and highest concentrations of GC-MS detectable compounds. The extracts were subjected to a battery of in vitro toxicity tests measuring both acute and sublethal cytotoxicity and genotoxic effects. None of the water or Tenax extracts was positive in cytotoxicity or genotoxicity assays. The ethanol extract of the non-food contact board gave a positive response in the genotoxicity assays, and all four ethanol extracts gave positive response(s) in the cytotoxicity assays to some extent. These responses could not be pinpointed to any specific compound, although there appeared a correlation between the total amount of extractables and toxicity.

Antioxidant, genotoxic and antigenotoxic activities of daphne gnidium leaf extracts

PubMed Central

2012-01-01

Background Plants play a significant role in maintaining human health and improving the quality of human life. They serve humans well as valuable components of food, as well as in cosmetics, dyes, and medicines. In fact, many plant extracts prepared from plants have been shown to exert biological activity in vitro and in vivo. The present study explored antioxidant and antigenotoxic effects of Daphne gnidium leaf extracts. Methods The genotoxic potential of petroleum ether, chloroform, ethyl acetate, methanol and total oligomer flavonoid (TOF) enriched extracts from leaves of Daphne gnidium, was assessed using Escherichia coli PQ37. Likewise, the antigenotoxicity of the same extracts was tested using the “SOS chromotest test”. Antioxidant activities were studied using non enzymatic and enzymatic method: NBT/Riboflavine and xantine oxidase. Results None of the different extracts produced a genotoxic effect, except TOF extract at the lowest tested dose. Our results showed that D. gnidium leaf extracts possess an antigenotoxic effect against the nitrofurantoin a mutagen of reference. Ethyl acetate and TOF extracts were the most effective in inhibiting xanthine oxidase activity. While, methanol extract was the most potent superoxide scavenger when tested with the NBT/Riboflavine assay. Conclusions The present study has demonstrated that D. gnidium leaf extract possess antioxidant and antigenotoxic effects. These activities could be ascribed to compounds like polyphenols and flavonoid. Further studies are required to isolate the active molecules. PMID:22974481

Comparison of cytotoxic and genotoxic effects of plutonium-239 alpha particles and mobile phone GSM 900 radiation in the Allium cepa test.

PubMed

Pesnya, Dmitry S; Romanovsky, Anton V

2013-01-20

The goal of this study was to compare the cytotoxic and genotoxic effects of plutonium-239 alpha particles and GSM 900 modulated mobile phone (model Sony Ericsson K550i) radiation in the Allium cepa test. Three groups of bulbs were exposed to mobile phone radiation during 0 (sham), 3 and 9h. A positive control group was treated during 20min with plutonium-239 alpha-radiation. Mitotic abnormalities, chromosome aberrations, micronuclei and mitotic index were analyzed. Exposure to alpha-radiation from plutonium-239 and exposure to modulated radiation from mobile phone during 3 and 9h significantly increased the mitotic index. GSM 900 mobile phone radiation as well as alpha-radiation from plutonium-239 induced both clastogenic and aneugenic effects. However, the aneugenic activity of mobile phone radiation was more pronounced. After 9h of exposure to mobile phone radiation, polyploid cells, three-groups metaphases, amitoses and some unspecified abnormalities were detected, which were not registered in the other experimental groups. Importantly, GSM 900 mobile phone radiation increased the mitotic index, the frequency of mitotic and chromosome abnormalities, and the micronucleus frequency in a time-dependent manner. Due to its sensitivity, the A. cepa test can be recommended as a useful cytogenetic assay to assess cytotoxic and genotoxic effects of radiofrequency electromagnetic fields. Copyright © 2012 Elsevier B.V. All rights reserved.

Safety assessment of non-animal chondroitin sulfate sodium: Subchronic study in rats, genotoxicity tests and human bioavailability.

PubMed

Miraglia, Niccolò; Bianchi, Davide; Trentin, Antonella; Volpi, Nicola; Soni, Madhu G

2016-07-01

Chondroitin sulfate, an amino sugar polymer made of glucuronic acid and N-acetyl-galactosamine, is used in dietary supplements to promote joint health. Commonly used chondroitin sulfate is of animal origin and can pose potential safety problems including bovine spongiform encephalopathy (BSE). The objective of the present study was to investigate potential adverse effects, if any, of microbial derived chondroitin sulfate sodium (CSS) in subchronic toxicity, genotoxicity and bioavailability studies. In the toxicity study, Sprague Dawley rats (10/sex/group) were gavaged with CSS at dose levels of 0, 250, 500 and 1000 mg/kg body weight (bw)/day for 90-days. No mortality or significant changes in clinical signs, body weights, body weight gain or feed consumption were noted. Similarly, no toxicologically relevant treatment-related changes in hematological, clinical chemistry, urinalysis and organ weights were noted. Macroscopic and microscopic examinations did not reveal treatment-related abnormalities. In vitro mutagenic and clastogenic potentials as evaluated by Ames assay, chromosomal aberration test and micronucleus assay did not reveal genotoxicity of CSS. In pharmacokinetic study in human, CSS showed higher absorption as compared to chondroitin sulfate of animal origin. The results of subchronic toxicity study supports the no-observed-adverse-effect level (NOAEL) for CSS as 1000 mg/kg bw/day, the highest dose tested. Copyright © 2016 Elsevier Ltd. All rights reserved.

Comparative In Vitro Toxicity Profile of Electronic and Tobacco Cigarettes, Smokeless Tobacco and Nicotine Replacement Therapy Products: E-Liquids, Extracts and Collected Aerosols

PubMed Central

Misra, Manoj; Leverette, Robert D.; Cooper, Bethany T.; Bennett, Melanee B.; Brown, Steven E.

2014-01-01

The use of electronic cigarettes (e-cigs) continues to increase worldwide in parallel with accumulating information on their potential toxicity and safety. In this study, an in vitro battery of established assays was used to examine the cytotoxicity, mutagenicity, genotoxicity and inflammatory responses of certain commercial e-cigs and compared to tobacco burning cigarettes, smokeless tobacco (SLT) products and a nicotine replacement therapy (NRT) product. The toxicity evaluation was performed on e-liquids and pad-collected aerosols of e-cigs, pad-collected smoke condensates of tobacco cigarettes and extracts of SLT and NRT products. In all assays, exposures with e-cig liquids and collected aerosols, at the doses tested, showed no significant activity when compared to tobacco burning cigarettes. Results for the e-cigs, with and without nicotine in two evaluated flavor variants, were very similar in all assays, indicating that the presence of nicotine and flavors, at the levels tested, did not induce any cytotoxic, genotoxic or inflammatory effects. The present findings indicate that neither the e-cig liquids and collected aerosols, nor the extracts of the SLT and NRT products produce any meaningful toxic effects in four widely-applied in vitro test systems, in which the conventional cigarette smoke preparations, at comparable exposures, are markedly cytotoxic and genotoxic. PMID:25361047

Toxicologic evaluation of DHA-rich algal oil: Genotoxicity, acute and subchronic toxicity in rats.

PubMed

Schmitt, D; Tran, N; Peach, J; Bauter, M; Marone, P

2012-10-01

DHA-rich algal oil ONC-T18, tested in a battery of in vitro and in vivo genotoxicity tests, did not show mutagenic or genotoxic potential. The acute oral LD50 in rats has been estimated to be greater than 5000 mg/kg of body weight. In a 90-day subchronic dietary study, administration of DHA-rich algal oil at concentrations of 0, 10,000, 25,000, and 50,000 ppm in the diet for 13 weeks did not produce any significant toxicologic manifestations. The algal oil test article was well tolerated as evidenced by the absence of major treatment-related changes in the general condition and appearance of the rats, neurobehavioral endpoints, growth, feed and water intake, ophthalmoscopic examinations, routine hematology and clinical chemistry parameters, urinalysis, or necropsy findings. The no observed adverse effect level (NOAEL) was the highest level fed of 50,000 ppm which is equivalent to 3,305 and 3,679 mg/kg bw/day, for male and female rats, respectively. The studies were conducted as part of an investigation to examine the safety of DHA-rich algal oil. The results confirm that it possesses a toxicity profile similar to other currently marketed algal oils and support the safety of DHA-rich algal oil for its proposed use in food. Copyright © 2012 Elsevier Ltd. All rights reserved.

Characterization of a Melamino Nitroheterocycle as a Potential Lead for the Treatment of Human African Trypanosomiasis

PubMed Central

Giordani, Federica; Buschini, Annamaria; Baliani, Alessandro; Kaiser, Marcel; Brun, Reto; Barrett, Michael P.; Pellacani, Claudia; Poli, Paola

2014-01-01

This paper reports an evaluation of a melamino nitroheterocycle, a potential lead for further development as an agent against human African trypanosomiasis (HAT). Studies on its efficacy, physicochemical and biopharmaceutical properties, and potential for toxicity are described. The compound previously had been shown to possess exceptional activity against Trypanosoma brucei in in vitro assays comparable to that of melarsoprol. Here, we demonstrate that the compound also was curative in the stringent acute mouse model T. brucei rhodesiense STIB 900 when given intraperitoneally at 40 mg/kg of body weight. Nevertheless, activity was only moderate when the oral route was used, and no cure was obtained when the compound was tested in a stage 2 rodent model of infection. Genotoxic profiling revealed that the compound induces DNA damage by a mechanism apparently independent from nitroreduction and involving the introduction of base pair substitutions (Ames test), possibly caused by oxidative damage of the DNA (comet test). No significant genotoxicity was observed at the chromosome level (micronucleus assay). The lack of suitable properties for oral and central nervous system uptake and the genotoxic liabilities prevent the progression of this melamine nitroheterocycle as a drug candidate for HAT. Further modification of the compound is required to improve the pharmacokinetic properties of the molecule and to separate the trypanocidal activity from the toxic potential. PMID:25022590

DNA Protection against Oxidative Damage Using the Hydroalcoholic Extract of Garcinia mangostana and Alpha-Mangostin.

PubMed

Carvalho-Silva, Ronaldo; Pereira, Alanna Cibelle Fernandes; Dos Santos Alves, Rúbens Prince; Guecheva, Temenouga N; Henriques, João A P; Brendel, Martin; Pungartnik, Cristina; Rios-Santos, Fabrício

2016-01-01

Garcinia mangostana, popularly known as "mangosteen fruit," originates from Southeast Asia and came to Brazil about 80 years ago where it mainly grows in the states of Pará and Bahia. Although mangosteen or its extracts have been used for ages in Asian folk medicine, data on its potential genotoxicity is missing. We, therefore, evaluated genotoxicity/mutagenicity of hydroethanolic mangosteen extract [HEGM, 10 to 640 μg/mL] in established test assays (Comet assay, micronucleus test, and Salmonella/microsome test). In the Comet assay, HEGM-exposed human leukocytes showed no DNA damage. No significant HEGM-induced mutation in TA98 and TA100 strains of Salmonella typhimurium (with or without metabolic activation) was observed and HEGM-exposed human lymphocytes had no increase of micronuclei. However, HEGM suggested exposure concentration-dependent antigenotoxic potential in leukocytes and antioxidant potential in the yeast Saccharomyces cerevisiae. HEGM preloading effectively protected against H2O2-induced DNA damage in leukocytes (Comet assay). Preloading of yeast with HEGM for up to 4 h significantly protected the cells from lethality of chronic H2O2-exposure, as expressed in better survival. Absence of genotoxicity and demonstration of an antigenotoxic and antioxidant potential suggest that HEGM or some substances contained in it may hold promise for pharmaceutical or nutraceutical application.

DNA Protection against Oxidative Damage Using the Hydroalcoholic Extract of Garcinia mangostana and Alpha-Mangostin

PubMed Central

Carvalho-Silva, Ronaldo; Pereira, Alanna Cibelle Fernandes; dos Santos Alves, Rúbens Prince; Guecheva, Temenouga N.; Henriques, João A. P.; Brendel, Martin; Rios-Santos, Fabrício

2016-01-01

Garcinia mangostana, popularly known as “mangosteen fruit,” originates from Southeast Asia and came to Brazil about 80 years ago where it mainly grows in the states of Pará and Bahia. Although mangosteen or its extracts have been used for ages in Asian folk medicine, data on its potential genotoxicity is missing. We, therefore, evaluated genotoxicity/mutagenicity of hydroethanolic mangosteen extract [HEGM, 10 to 640 μg/mL] in established test assays (Comet assay, micronucleus test, and Salmonella/microsome test). In the Comet assay, HEGM-exposed human leukocytes showed no DNA damage. No significant HEGM-induced mutation in TA98 and TA100 strains of Salmonella typhimurium (with or without metabolic activation) was observed and HEGM-exposed human lymphocytes had no increase of micronuclei. However, HEGM suggested exposure concentration-dependent antigenotoxic potential in leukocytes and antioxidant potential in the yeast Saccharomyces cerevisiae. HEGM preloading effectively protected against H2O2-induced DNA damage in leukocytes (Comet assay). Preloading of yeast with HEGM for up to 4 h significantly protected the cells from lethality of chronic H2O2-exposure, as expressed in better survival. Absence of genotoxicity and demonstration of an antigenotoxic and antioxidant potential suggest that HEGM or some substances contained in it may hold promise for pharmaceutical or nutraceutical application. PMID:27042187

Protection by beverages, fruits, vegetables, herbs, and flavonoids against genotoxicity of 2-acetylaminofluorene and 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) in metabolically competent V79 cells.

PubMed

Edenharder, R; Sager, J W; Glatt, H; Muckel, E; Platt, K L

2002-11-26

Chinese hamster lung fibroblasts, genetically engineered for the expression of rat cytochrome P450 dependent monooxygenase 1A2 and rat sulfotransferase 1C1 (V79-rCYP1A2-rSULT1C1 cells), were utilized to check for possible protective effects of beverages of plant origin, fruits, vegetables, and spices against genotoxicity induced by 2-acetylaminofluorene (AAF) or 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP). Antigenotoxic activities of juices from spinach and red beets against AAF could be monitored with similar effectivity by the HPRT-mutagenicity test (IC(50)=0.64%; 2.57%) and alkaline single cell gel electrophoresis (comet assay; IC(50)=0.12%; 0.89%) which detects DNA strand breaks and abasic sites. Applying the comet assay, genotoxicity of PhIP could, however, be demonstrated only in the presence of hydroxyurea and 1-[beta-D-arabinofuranosyl]cytosine, known inhibitors of DNA repair synthesis. As expected, AAF and PhIP were unable to induce any genotoxic effects in the parent V79 cells. Genotoxic activity of PhIP was strongly reduced in a dose-related manner by green tea and red wine, by blueberries, blackberries, red grapes, kiwi, watermelon, parsley, and spinach, while two brands of beer, coffee, black tea, rooibos tea, morellos, black-currants, plums, red beets, broccoli (raw and cooked), and chives were somewhat less active. One brand of beer was only moderately active while white wine, bananas, white grapes, and strawberries were inactive. Similarly, genotoxicity of AAF was strongly reduced by green, black, and rooibos tea, red wine, morellos, black-currants, kiwi, watermelon, and spinach while plums, red beets, and broccoli (raw) were less potent. Broccoli cooked exerted only moderate and white wine weak antigenotoxic activity. With respect to the possible mechanism(s) of inhibition of genotoxicity, benzo[a]pyrene-7,8-dihydrodiol (BaP-7,8-OH) and N-OH-PhIP were applied as substrates for the CYP1A family and for rSULT 1C1, respectively. Morellos, black-currants, and black tea strongly reduced the genotoxicity of BaP-7,8-OH, onions, rooibos tea, and red wine were less potent while red beets and spinach were inactive. On the other hand, red beets and spinach strongly inhibited the genotoxicity of N-OH-PhIP, rooibos tea was weakly active while all other items were inactive. These results are suggestive for enzyme inhibition as mechanism of protection by complex mixtures of plant origin. Taken together, our results demonstrate that protection by beverages, fruits, and vegetables against genotoxicity of heterocyclic aromatic amines may take place within metabolically competent mammalian cells as well as under the conditions of the Salmonella/reversion assay.

Comparison of Reversibility of Rat Forestomach Lesions Induced by Genotoxic and Non‐genotoxic Carcinogens

PubMed Central

Kagawa, Masataka; Hakoi, Kazuo; Yamamoto, Atsushi; Futakuchi, Mitsuru

1993-01-01

Reversibility of forestomach lesions induced by genotoxic and non‐genotoxic carcinogens was compared histopathologically. Groups of 30 to 33 male F344 rats were given dietary 0.1% 8‐nitroquinoline, dietary 0.4–0.2% 2‐(2‐furyl)‐3‐(5‐nitro‐2‐furyl)acrylamide, an intragastric dose of 20 mg/kg body weight N‐methyl‐N′‐nitro‐N‐nitrosoguanidine once a week, or 20 ppm N‐methylnitrosourethane in the drinking water as a genotoxic carcinogen, or 2% butylated hydroxyanisole, 2% caffeic acid, 2% sesamol or 2% 4‐methoxyphenol in the diet as a non‐genotoxic carcinogen for 24 weeks. Ten or 11 rats in each group were killed at week 24. Half of the remainder were maintained on basal diet alone for an additional 24 weeks and the other half were given the same chemical for 48 weeks, and then killed. Forestomach lesions induced by genotoxic carcinogens did not regress after removal of carcinogens. In contrast, simple or papillary hyperplasia (SPH), but not basal cell hyperplasia (BCH), induced by non‐genotoxic carcinogens clearly regressed after cessation of insult. SFH labeling indices in the non‐genotoxic carcinogen‐treated cases decreased after removal of the carcinogenic stimulus whereas BCH values were low irrespective of treatment. Atypical hyperplasia (AH), observed at high incidences in rats treated with genotoxic carcinogens, was also evident in animals receiving non‐genotoxic agents, even after their withdrawal, albeit at low incidences. AH labeling indices remained high even without continued insult. These results indicate that even with non‐genotoxic carcinogens, heritable alterations at the DNA level could occur during strong cell proliferation and result in AH development. This putative preneoplastic lesion might then progress to produce carcinomas. PMID:8276717

Vanillin as a modulator agent in SMART test: inhibition in the steps that precede N-methyl-N-nitrosourea-, N-ethyl-N-nitrosourea-, ethylmethanesulphonate- and bleomycin-genotoxicity.

PubMed

Sinigaglia, Marialva; Lehmann, Maurício; Baumgardt, Paula; do Amaral, Viviane Souza; Dihl, Rafael Rodrigues; Reguly, Maria Luíza; de Andrade, Heloísa Helena Rodrigues

2006-09-05

Vanillin (VA), the world's major flavoring compound used in food industry and confectionery products - that has antimutagenic and anticarcinogenic activity against a variety of mutagenic/carcinogenic agents - was tested for the interval between the formation of premutational lesion and it is finalization as a DNA lesion. The overall findings using co-treatment protocols in SMART test suggest that VA can lead to a significant protection against the general genotoxicity of ethylmethanesulphonate (EMS), N-ethyl-N-nitrosourea (ENU), N-methyl-N-nitrosourea (MNU) and bleomycin sulphate (BLEO). Considering MNU, ENU and EMS the desmutagenic activity observed could result from VA-stimulation of detoxification, via induction of glutathione S-transferase. However, the protector effect related to BLEO could be attributed to its powerful scavenger ability, which has the potential to prevent oxidative damage induced by BLEO.

Enzymes oxidizing the azo dye 1-phenylazo-2-naphthol (Sudan I) and their contribution to its genotoxicity and carcinogenicity.

PubMed

Stiborova, Marie; Schmeiser, Heinz H; Frei, Eva; Hodek, Petr; Martinek, Vaclav

2014-01-01

Sudan I [1-(phenylazo)-2-naphthol, C.I. Solvent Yellow 14] is an industrial dye, which was found as a contaminant in numerous foods in several European countries. Because Sudan I has been assigned by the IARC as a Category 3 carcinogen, the European Union decreed that it cannot be utilized as food colorant in any European country. Sudan I induces the malignancies in liver and urinary bladder of rats and mice. This carcinogen has also been found to be a potent mutagen, contact allergen and sensitizer, and exhibits clastogenic properties. The oxidation of Sudan I increases its toxic effects and leads to covalent adducts in DNA. Identification of enzymatic systems that contribute to Sudan I oxidative metabolism to reactive intermediates generating such covalent DNA adducts on the one hand, and to the detoxification of this carcinogen on the other, is necessary to evaluate susceptibility to this toxicant. This review summarizes the identification of such enzymes and the molecular mechanisms of oxidation reactions elucidated to date. Human and animal cytochrome P450 (CYP) and peroxidases are capable of oxidizing Sudan I. Of the CYP enzymes, CYP1A1 is most important both in Sudan I detoxification and its bio-activation. Ring-hydroxylated metabolites and a dimer of this carcinogen were found as detoxification products of Sudan I generated with CYPs and peroxidases, respectively. Oxidative bio-activation of this azo dye catalyzed by CYPs and peroxidases leads to generation of proximate genotoxic metabolites (the CYP-catalyzed formation of the benzenediazonium cation and the peroxidase-mediated generation of one-electron oxidation products), which covalently modify DNA both in vitro and in vivo. The predominant DNA adduct generated with the benzenediazonium cation was characterized to be 8-(phenylazo)guanine. The Sudan I radical species mediated by peroxidases reacts with the -NH2 group in (deoxy)guanosine, generating the 4-[(deoxy)guanosin-N(2)-yl]Sudan I product. Sudan I was also found to be a strong inducer of CYP1A1 and its enzyme activity mediated by the aryl hydrocarbon receptor, thereby increasing its own genotoxic potential and the cancer risk for humans.

Biochemical and genotoxic effect of triclosan on earthworms (Eisenia fetida) using contact and soil tests.

PubMed

Lin, Dasong; Xie, Xiujie; Zhou, Qixing; Liu, Yao

2012-07-01

Triclosan (TCS) is a broad-spectrum bactericide that is used for a variety of antimicrobial functions. TCS is frequently detected in the terrestrial environment due to application of sewage sludge to agricultural land. In the present study, 48-h paper contact and 28-day spiked soil tests were conducted to examine the toxic effects of TCS on the antioxidative and genetic indices of earthworms (Eisenia fetida). The activity of antioxidative enzymes (superoxide dismutase, SOD; catalase, CAT) and the content of the lipid peroxidation product (malondialdehyde, MDA) were determined as biomarkers of oxidative stress in E. fetida. Moreover, single cell gel electrophoresis (SCGE) was used as a biomarker of genotoxicity. The results showed that triclosan induced a significant increase (P < 0.05) in antioxidative enzyme activities and MDA content. Of all of the biomarkers examined, CAT activity was most sensitive to TCS, and the CAT activity increased significantly (P < 0.05) at bactericidal concentrations of 7.86 ng cm⁻² in the contact test and 10 mg kg⁻¹ in the spiked soil test. The comet assay showed that TCS treatments significantly induced (P < 0.05) DNA damage in E. fetida, and that 78.6 ng cm⁻² caused significant genotoxic effects in the acute test (48 h). Clear dose-dependent DNA damage to E. fetida was observed both in contact and spiked soil tests. These results imply that TCS may have potential biochemical and genetic toxicity toward earthworms (E. fetida). A battery of biomarkers covering multiple molecular targets of acute toxicity can be combined to better understand the impacts of TCS on E. fetida. Copyright © 2010 Wiley Periodicals, Inc.

In vitro genotoxicity of neutral red after photo-activation and metabolic activation in the Ames test, the micronucleus test and the comet assay.

PubMed

Guérard, Melanie; Zeller, Andreas; Singer, Thomas; Gocke, Elmar

2012-07-04

Neutral red (Nr) is relatively non-toxic and is widely used as indicator dye in many biological test systems. It absorbs visible light and is known to act as a photosensitizer, involving the generation of reactive oxygen species (type-I reaction) and singlet oxygen (type-II reaction). The mutagenicity of Nr was determined in the Ames test (with Salmonella typhimurium strains TA1535, TA97, TA98, TA98NR, TA100, and TA102) with and without metabolic activation, and with and without photo-activation on agar plates. Similarly to the situation following metabolic activation, photo-mutagenicity of Nr was seen with all Salmonella strains tested, albeit with different effects between these strains. To our knowledge, Nr is the only photo-mutagen showing such a broad action. Since the effects are also observed in strains not known to be responsive to ROS, this indicates that ROS production is not the sole mode of action that leads to photo-genotoxicity. The reactive species produced by irradiation are short-lived as pre-irradiation of an Nr solution did not produce mutagenic effects when added to the bacteria. In addition, mutagenicity in TA98 following irradiation was stronger than in the nitroreductase-deficient strain TA98NR, indicating that nitro derivatives that are transformed by bacterial nitroreductase to hydroxylamines appear to play a role in the photo-mutagenicity of Nr. Photo-genotoxicity of Nr was further investigated in the comet assay and micronucleus test in L5178Y cells. Concentration-dependent increases in primary DNA damage and in the frequency of micronuclei were observed after irradiation. Copyright © 2012 Elsevier B.V. All rights reserved.

Lycopene, resveratrol, vitamin C and FeSO4 increase damage produced by pro-oxidant carcinogen 4-nitroquinoline-1-oxide in Drosophila melanogaster: Xenobiotic metabolism implications.

PubMed

Dueñas-García, I E; Heres-Pulido, M E; Arellano-Llamas, M R; De la Cruz-Núñez, J; Cisneros-Carrillo, V; Palacios-López, C S; Acosta-Anaya, L; Santos-Cruz, L F; Castañeda-Partida, L; Durán-Díaz, A

2017-05-01

4-nitroquinoline-1-oxide (4-NQO) is a pro-oxidant carcinogen bioactivated by xenobiotic metabolism (XM). We investigated if antioxidants lycopene [0.45, 0.9, 1.8 μM], resveratrol [11, 43, 172 μM], and vitamin C [5.6 mM] added or not with FeSO 4 [0.06 mM], modulate the genotoxicity of 4-NQO [2 mM] with the Drosophila wing spot test standard (ST) and high bioactivation (HB) crosses, with inducible and high levels of cytochromes P450, respectively. The genotoxicity of 4-NQO was higher when dissolved in an ethanol - acetone mixture. The antioxidants did not protect against 4-NQO in any of both crosses. In the ST cross, resveratrol [11 μM], vitamin C and FeSO 4 resulted in genotoxicity; the three antioxidants and FeSO 4 increased the damage of 4-NQO. In the HB cross, none of the antioxidants, neither FeSO 4 , were genotoxic. Only resveratrol [172 μM] + 4-NQO increased the genotoxic activity in both crosses. We concluded that the effects of the antioxidants, FeSO 4 and the modulation of 4-NQO were the result of the difference of Cyp450s levels, between the ST and HB crosses. We propose that the basal levels of the XM's enzymes in the ST cross interacted with a putative pro-oxidant activity of the compounds added to the pro-oxidant effects of 4-NQO. Copyright © 2017. Published by Elsevier Ltd.

In vivo genotoxicity assessment in rats exposed to Prestige-like oil by inhalation.

PubMed

Valdiglesias, Vanessa; Kiliç, Gözde; Costa, Carla; Amor-Carro, Óscar; Mariñas-Pardo, Luis; Ramos-Barbón, David; Méndez, Josefina; Pásaro, Eduardo; Laffon, Blanca

2012-01-01

One of the largest oil spill disasters in recent times was the accident of the oil tanker Prestige in front of the Galician coast in 2002. Thousands of people participated in the cleanup of the contaminated areas, being exposed to a complex mixture of toxic substances. Acute and prolonged respiratory symptoms and genotoxic effects were reported, although environmental exposure measurements were restricted to current determinations, such that attribution of effects observed to oil exposure is difficult to establish. The aim of this study was to analyze peripheral blood leukocytes (PBL) harvested from a rat model of subchronic exposure to a fuel oil with similar characteristics to that spilled by the Prestige tanker, in order to determine potential genotoxic effects under strictly controlled, in vivo exposure. Wistar Han and Brown Norway rats were exposed to the oil for 3 wk, and micronucleus test (MN) and comet assay, standard and modified with 8-oxoguanine DNA glycosylase (OGG1) enzyme, were employed to assess genotoxicity 72 h and 15 d after the last exposure. In addition, the potential effects of oil exposure on DNA repair capacity were determined by means of mutagen sensitivity assay. Results obtained from this study showed that inhalation oil exposure induced DNA damage in both Brown Norway and Wistar Han rats, especially in those animals evaluated 15 d after exposure. Although alterations in the DNA repair responses were noted, the sensitivity to oil substances varied depending on rat strain. Data support previous positive genotoxicity results reported in humans exposed to Prestige oil during cleanup tasks.

GENOTOXICITY OF TOBACCO SMOKE AND TOBACCO SMOKE CONDENSATE: A REVIEW

EPA Science Inventory

Genotoxicity of Tobacco Smoke and Tobacco Smoke Condensate: A Review
Abstract
This report reviews the literature on the genotoxicity of main-stream tobacco smoke and cigarette smoke condensate (CSC) published since 1985. CSC is genotoxic in nearly all systems in which it h...

New nanostructural biomaterials based on active silicate systems and hydroxyapatite: characterization and genotoxicity in human peripheral blood lymphocytes.

PubMed

Opačić-Galić, V; Petrović, V; Zivković, S; Jokanović, V; Nikolić, B; Knežević-Vukčević, J; Mitić-Ćulafić, D

2013-06-01

To characterize and investigate the genotoxic effect of a new endodontic cement based on dicalcium- and tricalcium-silicate (CS) with hydroxyapatite (HA) on human lymphocytes. Hydrothermal treatment was applied for synthesis of CS and HA. The final mixture HA-CS, with potential to be used in endodontic practice, is composed of CS (34%) and HA (66%). Human lymphocytes were incubated with HA, HA-CS and CS for 1 h, at 37 °C and 5% CO2. Cell viability was determined using the trypan blue exclusion assay. To evaluate the level of DNA damage comet assay (single cell gel electrophoresis) was performed. For the statistical analysis anova and Duncan's Post Hoc Test were used. The SEM analysis indicated that CS consisted mostly of agglomerates of several micrometers in size, built up from smaller particles, with dimensions between 117 and 477 nm. This is promising because dimensions of agglomerates are not comparable with channels inside the cell membranes, whereas their nano-elements provide evident activity, important for faster setting of these mixtures compared to MTA. Values of DNA damage obtained in the comet assay indicated low genotoxic risk of the new endodontic materials. The significantly improved setting characteristics and low genotoxic risk of the new material support further research. © 2012 International Endodontic Journal.

No clastogenic activity of a senna extract in the mouse micronucleus assay.

PubMed

Mengs, U; Grimminger, W; Krumbiegel, G; Schuler, D; Silber, W; Völkner, W

1999-08-18

In previous studies, an analytically well-defined senna extract, commonly used as a laxative, gave positive responses in vitro in the Ames test and in the CHO assay. Therefore, the objective of this study was to investigate the genotoxic activity of the same senna extract in an in vivo genotoxicity assay by means of the generally acknowledged MNT. After administration of an oral dose of 2000 mg senna extract/kg to NMRI mice of both genders, which is equivalent to 119 mg potential rhein/kg, 5.74 mg potential aloeemodin/kg and 0. 28 mg potential emodin/kg, there were no elevated levels of micronuclei in bone marrow cells. Kinetic studies were performed in parallel to demonstrate target organ availability. Highest concentrations in the plasma were reached after 1 h with 3.4 microg rhein/ml and 0.065 microg aloeemodin/ml. In all cases, emodin was below the limit of quantification. From the results, the in vitro clastogenic activity of the senna extract could not be confirmed in the mouse micronucleus assay. Together with further negative in vivo genotoxicity studies with anthranoids, the conclusion can be drawn that there is no indication so far demonstrating a genotoxic risk for patients taking senna laxatives.

Fipronil-induced genotoxicity and DNA damage in vivo: Protective effect of vitamin E.

PubMed

Badgujar, P C; Selkar, N A; Chandratre, G A; Pawar, N N; Dighe, V D; Bhagat, S T; Telang, A G; Vanage, G R

2017-05-01

Fipronil, an insecticide of the phenylpyrazole class has been classified as a carcinogen by United States Environmental Protection Agency, yet very limited information is available about its genotoxic effects. Adult male and female animals were gavaged with various doses of fipronil (2.5, 12.5, and 25 mg/kg body weight (bw)) to evaluate micronucleus test (mice), chromosome aberration (CA), and comet assay (rats), respectively. Cyclophosphamide (40 mg/kg bw; intraperitoneal) was used as positive control. Another group of animals were pretreated with vitamin E orally (400 mg/kg bw) for 5 days prior to administration of fipronil (12.5 mg/kg). Fipronil exposure in both male and female mice caused significant increase in the frequency of micronuclei (MN) in polychromatic erythrocytes. Similarly, structural CAs in bone marrow cells and DNA damage in the lymphocytes was found to be significantly higher in the male and female rats exposed to fipronil as compared to their respective controls. The average degree of protection (male and female animals combined together) shown by pretreatment of vitamin E against fipronil-induced genotoxicity was 63.28%: CAs; 47.91%: MN formation; and 74.70%: DNA damage. Findings of this study demonstrate genotoxic nature of fipronil regardless of gender effect and documents protective role of vitamin E.

In vitro toxicological evaluation of essential oils and their main compounds used in active food packaging: A review.

PubMed

Llana-Ruiz-Cabello, Maria; Pichardo, Silvia; Maisanaba, Sara; Puerto, Maria; Prieto, Ana I; Gutiérrez-Praena, Daniel; Jos, Angeles; Cameán, Ana M

2015-07-01

Essential oils (EOs) and their main constituent compounds have been extensively investigated due to their application in the food industry for improving the shelf life of perishable products. Although they are still not available for use in food packaging in the market in Europe, considerable research in this field has been carried out recently. The safety of these EOs should be guaranteed before being commercialized. The aim of this work was to review the scientific publications, with a primary focus on the last 10 years, with respect to different in vitro toxicological aspects, mainly focussed on mutagenicity/genotoxicity. In general, fewer genotoxic studies have been reported on EOs in comparison to their main components, and most of them did not show mutagenic activity. However, more studies are needed in this field since the guidelines of the European Food Safety Authority have not always been followed accurately. The mutagenic/genotoxic activities of these substances have been related to metabolic activation. Therefore, in vivo tests are required to confirm the absence of genotoxic effects. Considering the great variability of the EOs and their main compounds, a case-by-case evaluation is needed to assure their safe use in food packaging. Copyright © 2015 Elsevier Ltd. All rights reserved.

Cytotoxicity and genotoxicity of biogenic silver nanoparticles

NASA Astrophysics Data System (ADS)

Lima, R.; Feitosa, L. O.; Ballottin, D.; Marcato, P. D.; Tasic, L.; Durán, N.

2013-04-01

Biogenic silver nanoparticles with 40.3 ± 3.5 nm size and negative surface charge (- 40 mV) were prepared with Fusarium oxysporum. The cytotoxicity of 3T3 cell and human lymphocyte were studied by a TaliTM image-based cytometer and the genotoxicity through Allium cepa and comet assay. The results of BioAg-w (washed) and BioAg-nw (unwashed) biogenic silver nanoparticles showed cytotoxicity exceeding 50 μg/mL with no significant differences of response in 5 and 10 μg/mL regarding viability. Results of genotoxicity at concentrations 5.0 and 10.0 ug/mL show some response, but at concentrations 0.5 and 1.0 μg/mL the washed and unwashed silver nanoparticles did not present any effect. This in an important result since in tests with different bacteria species and strains, including resistant, MIC (minimal inhibitory concentration) had good answers at concentrations less than 1.9 μg/mL. This work concludes that biogenic silver nanoparticles may be a promising option for antimicrobial use in the range where no cyto or genotoxic effect were observed. Furthermore, human cells were found to have a greater resistance to the toxic effects of silver nanoparticles in comparison with other cells.

New investigations into the genotoxicity of cobalt compounds and their impact on overall assessment of genotoxic risk.

PubMed

Kirkland, David; Brock, Tom; Haddouk, Hasnaà; Hargeaves, Victoria; Lloyd, Melvyn; Mc Garry, Sarah; Proudlock, Raymond; Sarlang, Séverine; Sewald, Katherina; Sire, Guillaume; Sokolowski, Andrea; Ziemann, Christina

2015-10-01

The genotoxicity of cobalt metal and cobalt compounds has been widely studied. Several publications show induction of chromosomal aberrations, micronuclei or DNA damage in mammalian cells in vitro in the absence of S9. Mixed results were seen in gene mutation studies in bacteria and mammalian cells in vitro, and in chromosomal aberration or micronucleus assays in vivo. To resolve these inconsistencies, new studies were performed with soluble and poorly soluble cobalt compounds according to OECD-recommended protocols. Induction of chromosomal damage was confirmed in vitro, but data suggest this may be due to oxidative stress. No biologically significant mutagenic responses were obtained in bacteria, Tk(+/-) or Hprt mutation tests. Negative results were also obtained for chromosomal aberrations (in bone marrow and spermatogonia) and micronuclei at maximum tolerated doses in vivo. Poorly soluble cobalt compounds do not appear to be genotoxic. Soluble compounds do induce some DNA and chromosomal damage in vitro, probably due to reactive oxygen. The absence of chromosome damage in robust GLP studies in vivo suggests that effective protective processes are sufficient to prevent oxidative DNA damage in whole mammals. Overall, there is no evidence of genetic toxicity with relevance for humans of cobalt substances and cobalt metal. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

Combined cyto/genotoxic activity of a selected antineoplastic drug mixture in human circulating blood cells.

PubMed

Gajski, Goran; Gerić, Marko; Domijan, Ana-Marija; Garaj-Vrhovac, Vera

2016-12-01

Antineoplastic drugs are highly cytotoxic chemotherapeutic agents that can often interfere directly or indirectly with the cell's genome. In an environmental or medical setting simultaneous exposure may occur. Such multiple exposures may pose a higher risk than it could be assumed from the studies evaluating the effect of a single substance. Therefore, in the present study we tested the combined cyto/genotoxicity of a mixture of selected antineoplastic drugs with different mechanisms of action (5-fluorouracil, etoposide, and imatinib mesylate) towards human lymphocytes in vitro. The results suggest that the selected antineoplastic drug mixture is potentially cyto/genotoxic and that it can induce cell and genome damage even at low concentrations. Moreover, the changes in the measured oxidative stress parameters suggest the participation of reactive oxygen species in the cyto/genotoxicity of the selected mixture. The obtained results indicate not only that such mixtures may pose a risk to cell and genome integrity, but also that single compound toxicity data are not sufficient for the predicting toxicity in a complex environment. Altogether, the results emphasise the need for further toxicological screening of antineoplastic drug mixtures, especially at low environmentally relevant concentrations, as to avoid any possible adverse effects on the environment and human health. Copyright © 2016 Elsevier Ltd. All rights reserved.

The role of natural indigo dye in alleviation of genotoxicity of sodium dithionite as a reducing agent.

PubMed

Bektaş, İdris; Karaman, Şengül; Dıraz, Emel; Çelik, Mustafa

2016-12-01

Indigo blue is a natural dye used for thousands of years by civilizations to dye fabric blue and it is naturally obtained from Isatis tinctoria. I. tinctoria is not only used for extraction of indigo blue color but also used medicinally in Traditional Chinese Medicine because of its active compounds. Sodium dithionite (Na 2 S 2 O 4 ) is used in dye bath for indigo blue extraction, but this reducing agent and its derivatives are major pollutants of textile industry and subsequently have hazardous influences on public health. Herein, the present study was designed to obtain the high yield of natural indigo dye but with low possible toxic effect. In this context, genotoxic effects of particular combinations of natural dye solutions obtained from Isatis tinctoria subsp. tomentolla with Na 2 S 2 O 4 as reducing agent were investigated. Dye solutions were obtained using two different pH levels (pH 9 and 11) and three different concentrations of Na 2 S 2 O 4 (2.5, 5 and 10 mg/ml). In addition to the dye solutions and reducing agent, aqueous extracts of I. tinctoria were assessed for their genotoxicity on human lymphocytes. For in vitro testing of genotoxicity, chromosomal aberrations (CAs), sister chromatid exchanges (SCEs) and mitotic indexes (MI) assays were used. Accordingly, Na 2 S 2 O 4 caused significant increases in CA and SCE as well decrease in MI but the genotoxic effects of sodium dithionite were reduced with natural indigo dye. As a result, aqueous extracts of Isatis leaves removed the toxic effects of sodium dithionite and showed anti-genotoxic effect. For the optimal and desired quality but with less toxic effects of natural dye, 2.5 mg/ml (for wool yarn) and 5 mg/ml (for cotton yarn) of Na 2 S 2 O 4 doses were found to be the best doses for reduction in the dye bath at Ph 9.

75 FR 61148 - Food and Drug Administration Modernization Act of 1997: Modifications to the List of Recognized...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-10-04

... Evaluation and testing within a risk management process 2-100 ASTM E1372-95 (2003) Standard Test Method...) Standard Title, Type of Test Method for Agar Diffusion Cell standard , Relevant Culture Screening for... Biological evaluation of medical devices - Office(s) and Part 3: Tests for genotoxicity, Division(s...

Evaluation of the genotoxic potential of Mangifera indica L. extract (Vimang), a new natural product with antioxidant activity.

PubMed

Rodeiro, I; Cancino, L; González, J E; Morffi, J; Garrido, G; González, R M; Nuñez, A; Delgado, R

2006-10-01

Mangifera indica L. extract (Vimang) consists of a defined mixture of components (polyphenols, terpenoids, steroids, fatty acids and microelements). It contains a variety of polyphenols, phenolic esters, flavan-3-ols and a xanthone (mangiferin), as main component. This extract has antioxidant action, antitumor and immunemodulatory effects proved in experimental models in both in vitro and in vivo assays. The present study was performed to investigate the genotoxicity potential activity of Vimang assessed through different tests: Ames, Comet and micronucleus assays. Positive and negative controls were included in each experimental series. Histidine requiring mutants of Salmonella typhimurium TA1535, TA1537, TA1538, TA98, TA100 and TA102 strains for point-mutation tests and in vitro micronucleus assay in primary human lymphocytes with and without metabolic activation were performed. In addition, genotoxic effects were evaluated on blood peripheral lymphocytes of NMRI mice of both sexes, which were treated during 2 days with intraperitoneal doses of M. indica L. extract (50-150 mg/kg). The observed results permitted to affirm that Vimang (200-5,000 microg/plate) did not increase the frequency of reverse mutations in the Ames test in presence or not of metabolic activation. Results of Comet assay showed that the extract did not induce single strand breaks or alkali-labile sites on blood peripheral lymphocytes of treated animals compared with controls. On the other hand, the results of the micronucleus studies (in vitro and in vivo) showed Vimang induces cytotoxic activity, determined as cell viability or PCE/NCE ratio, but neither increased the frequency of micronucleated binucleate cells in culture of human lymphocytes nor in mice bone marrow cells under our experimental conditions. The positive control chemicals included in each experiment induced the expected changes. The present results indicate that M. indica L. extract showed evidences of light cytotoxic activity but did not induce a mutagenic or genotoxic effects in the battery of assays used.

Integrating High-Dimensional Transcriptomics and Image Analysis Tools into Early Safety Screening: Proof of Concept for a New Early Drug Development Strategy.

PubMed

Verbist, Bie M P; Verheyen, Geert R; Vervoort, Liesbet; Crabbe, Marjolein; Beerens, Dominiek; Bosmans, Cindy; Jaensch, Steffen; Osselaer, Steven; Talloen, Willem; Van den Wyngaert, Ilse; Van Hecke, Geert; Wuyts, Dirk; Van Goethem, Freddy; Göhlmann, Hinrich W H

2015-10-19

During drug discovery and development, the early identification of adverse effects is expected to reduce costly late-stage failures of candidate drugs. As risk/safety assessment takes place rather late during the development process and due to the limited ability of animal models to predict the human situation, modern unbiased high-dimensional biology readouts are sought, such as molecular signatures predictive for in vivo response using high-throughput cell-based assays. In this theoretical proof of concept, we provide findings of an in-depth exploration of a single chemical core structure. Via transcriptional profiling, we identified a subset of close analogues that commonly downregulate multiple tubulin genes across cellular contexts, suggesting possible spindle poison effects. Confirmation via a qualified toxicity assay (in vitro micronucleus test) and the identification of a characteristic aggregate-formation phenotype via exploratory high-content imaging validated the initial findings. SAR analysis triggered the synthesis of a new set of compounds and allowed us to extend the series showing the genotoxic effect. We demonstrate the potential to flag toxicity issues by utilizing data from exploratory experiments that are typically generated for target evaluation purposes during early drug discovery. We share our thoughts on how this approach may be incorporated into drug development strategies.

Identification of genotoxic compounds in crude oil using fractionation according to distillation, polarity and Kow.

PubMed

Park, Shin Yeong; Lee, Hyo Jin; Khim, Jong Seong; Kim, Gi Beum

2017-01-30

We examined the degree of DNA damage caused by fractions of crude oil in accordance with the boiling points, polarity and log K ow . Relatively high DNA damage was observed in the aromatic fraction (290-330°C) and resin and polar fraction (350-400°C). The resin and polar fraction showed relatively high genotoxicity compared with the aliphatic and aromatic fraction at the 1-4 log K ow range. At the 6-7 log K ow range, the aromatic fraction showed relatively high DNA damage compared with the aliphatic and resin and polar fraction. In particular, every detailed fraction in accordance with the log K ow values (aliphatic and aromatic (310-320°C) and resins and polar fractions (370-380°C)) showed one or less than one DNA damage. However, the fractions before separation in accordance with log K ow values (aliphatic and aromatic (310-320°C) and resin and polar (370-380°C) fractions) showed high DNA damage. Thus, we confirm the synergistic action between the detailed compounds. Copyright © 2016 Elsevier Ltd. All rights reserved.

Evaluating ToxCast™ High-Throughput Assays For Their Ability To Detect Direct-Acting Genotoxicants

EPA Science Inventory

A standard battery of tests has been in use for the several decades to screen chemicals for genotoxicity. However, the large number of environmental and industrial chemicals that need to be tested overwhelms our ability to test them. ToxCast™ is a multi-year effort to develop a ...

Genotoxicity of municipal landfill leachate on root tips of Vicia faba.

PubMed

Sang, Nan; Li, Guangke

2004-06-13

The genotoxicity of municipal landfill leachate was studied using the Vicia faba root-tip cytogenetic bioassay. Results show that landfill leachates collected in different seasons decreased the mitotic index (MI) and caused significant increases of micronucleus (MN) frequencies and anaphase aberration (AA) frequencies in a concentration-dependent manner (concentration expressed as 'chemical oxygen demand' measured by the method of potassium dichromate oxidation (COD(Cr))). In addition, a seasonal difference in genotoxicity induced by leachate was observed. The results confirm that leachate is a genotoxic agent in plant cells and imply that exposure to leachate in the aquatic environment may pose a potential genotoxic risk to organisms. The results also show that the V. faba cytogenetic bioassay is efficient, simple and reproducible in genotoxicity studies of leachate, and that there is a correlation between the genotoxicity and the chemical measurement (COD(Cr)) of leachate.

Genotoxicity and cytotoxicity assessment in lake drinking water produced in a treatment plant.

PubMed

Buschini, Annamaria; Carboni, Pamela; Frigerio, Silvia; Furlini, Mariangela; Marabini, Laura; Monarca, Silvano; Poli, Paola; Radice, Sonia; Rossi, Carlo

2004-09-01

Chemical analyses and short-term mutagenicity bioassays have revealed the presence of genotoxic disinfection by-products in drinking water. In this study, the influence of the different steps of surface water treatment on drinking water mutagen content was evaluated. Four different samples were collected at a full-scale treatment plant: raw lake water (A), water after pre-disinfection with chlorine dioxide and coagulation (B), water after pre-disinfection, coagulation and granular activated carbon filtration (C) and tap water after post-disinfection with chlorine dioxide just before its distribution (D). Water samples, concentrated by solid phase adsorption on silica C18 columns, were tested in human leukocytes and HepG2 hepatoma cells using the comet assay and in HepG2 cells in the micronuclei test. A significant increase in DNA migration was observed in both cell types after 1 h treatment with filtered and tap water, and, to a lesser extent, chlorine dioxide pre-disinfected water. Similar findings were observed for the induction of "ghost" cells. Overloading of the carbon filter, with a consequent peak release, might explain the high genotoxicity found in water samples C and D. Cell toxicity and DNA damage increases were also detected in metabolically competent HepG2 cells treated with a lower concentration of tap water extract for a longer exposure time (24 h). None of the water extracts significantly increased micronuclei frequencies. Our monitoring approach appears to be able to detect contamination related to the different treatment stages before drinking water consumption and the results suggest the importance of improving the technologies for drinking water treatment to prevent human exposure to potential genotoxic compounds.

Genotoxicity of 11 heavy metals detected as food contaminants in two human cell lines.

PubMed

Kopp, B; Zalko, D; Audebert, M

2018-04-01

Heavy metals, such as arsenic (As), antimony (Sb), barium (Ba), cadmium (Cd), cobalt (Co), germanium (Ge), lead (Pb), nickel (Ni), tellurium (Te), and vanadium (V) are widely distributed in the environment and in the food chain. Human exposure to heavy metals through water and food has been reported by different international agencies. Although some of these heavy metals are essential elements for human growth and development, they may also be toxic at low concentrations due to indirect mechanisms. In this study, the genotoxic and cytotoxic properties of 15 different oxidation statuses of 11 different heavy metals were investigated using high-throughput screening (γH2AX assay) in two human cell lines (HepG2 and LS-174T) representative of target organs (liver and colon) for food contaminants. Base on their lowest observed adverse effect concentration, the genotoxic potency of each heavy metal in each cell line was ranked in decreasing order, NaAsO 2  > CdCl 2  > PbCl 2 (only in LS-174T cells) > As 2 O 5  > SbCl 3  > K 2 TeO 3  > As 2 O 3 . No significant genotoxicity was observed with the other heavy metals tested. Cell viability data indicate that several heavy metals (As, Cd, Co, Ni, Sb, and Te) induce cytotoxicity at high concentrations, whereas an increase in the number of cells was observed for lead concentrations >100 µM in both cell lines tested, suggesting that lead stimulates cell growth. All these results highlight the possible human health hazards associated with the presence of heavy metals present in food. Environ. Mol. Mutagen. 59:202-210, 2018. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Physico-chemical characterization and the in vitro genotoxicity of medical implants metal alloy (TiAlV and CoCrMo) and polyethylene particles in human lymphocytes.

PubMed

Gajski, Goran; Jelčić, Zelimir; Oreščanin, Višnja; Gerić, Marko; Kollar, Robert; Garaj-Vrhovac, Vera

2014-01-01

The main objective of the present study was to investigate chemical composition and possible cyto/genotoxic potential of several medical implant materials commonly used in total hip joint replacement. Medical implant metal alloy (Ti6Al4V and CoCrMo) and high density polyethylene particles were analyzed by energy dispersive X-ray spectrometry while toxicological characterization was done on human lymphocytes using multi-biomarker approach. Energy dispersive X-ray spectrometry showed that none of the elements identified deviate from the chemical composition defined by appropriate ISO standard. Toxicological characterization showed that the tested materials were non-cyto/genotoxic as determined by the comet and cytokinesis-block micronucleus (CBMN) assay. Particle morphology was found (by using scanning electron and optical microscope) as flat, sharp-edged, irregularly shaped fiber-like grains with the mean particle size less than 10µm; this corresponds to the so-called "submicron wear". The very large surface area per wear volume enables high reactivity with surrounding media and cellular elements. Although orthopedic implants proved to be non-cyto/genotoxic, in tested concentration (10μg/ml) there is a constant need for monitoring of patients that have implanted artificial hips or other joints, to minimize the risks of any unwanted health effects. The fractal and multifractal analyses, performed in order to evaluate the degree of particle shape effect, showed that the fractal and multifractal terms are related to the "remnant" level of the particles' toxicity especially with the cell viability (trypan blue method) and total number of nucleoplasmic bridges and nuclear buds as CBMN assay parameters. © 2013.

Forskolin: genotoxicity assessment in Allium cepa.

PubMed

Mohammed, Khalid Pasha; Aarey, Archana; Tamkeen, Shayesta; Jahan, Parveen

2015-01-01

Forskolin, a diterpene, 7β-acetoxy-8,13-epoxy-1α,6β,9α-trihydroxy-labd-14-en-11-one (C22H34O7) isolated from Coleus forskohlii, exerts multiple physiological effects by stimulating the enzyme adenylate cyclase and increasing cyclic adenosine monophosphate (cAMP) concentrations. Forskolin is used in the treatment of hypertension, congestive heart failure, eczema, and other diseases. A cytogenetic assay was performed in Allium cepa to assess possible genotoxic effects of forskolin. Forskolin was tested at concentrations 5-100 μM for exposure periods of 24 or 48 h. Treated samples showed significant reductions in mitotic index (p < 0.05) and increases in the frequency of chromosome aberrations (p < 0.01) at both exposure times. The treated meristems showed chromosome aberrations including sticky metaphases, sticky anaphases, laggard, anaphase bridges, micronuclei, polyploidy, fragments, breaks, and C-mitosis. Forskolin may cause genotoxic effects and further toxicological evaluations should be conducted to ensure its safety. Copyright © 2014 Elsevier B.V. All rights reserved.

Current and emerging challenges in toxicopathology: Carcinogenic threshold of phenobarbital and proof of arsenic carcinogenicity using rat medium-term bioassays for carcinogens

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fukushima, Shoji; Morimura, Keiichirou; Wanibuchi, Hideki

2005-09-01

For the last 25 years, Prof. Nobuyuki Ito and his laboratory have focused on the development of liver medium-term bioassay system for detection of carcinogens in F344 rats utilizing glutathione S-transferase placental form (GST-P)-positive foci as an end point marker. In this presentation, the outline and samples of medium-term bioassay systems were described. Furthermore, our data demonstrated the presence of a threshold for the non-genotoxic carcinogen, phenobarbital (PB), and the lack of linearity in the low-dose area of the dose-response curve, providing evidence for hormesis. In addition, the establishment and applications of multiorgan carcinogenicity bioassay (DMBDD model), used for themore » examination of the carcinogenicity of genotoxic and non-genotoxic chemicals, are discussed. Dimethylarsinic acid, one of organic arsenics, was found to be carcinogenic in rat bladder using DMBDD model and carcinogenicity test.« less

A research on the genotoxicity of stevia in human lymphocytes.

PubMed

Uçar, Aslı; Yılmaz, Serkan; Yılmaz, Şemsigül; Kılıç, Mustafa Sefa

2018-04-01

Stevia extracts are obtained from Stevia rebaudiana commonly used as natural sweeteners. It is ∼250-300 times sweeter than sucrose. Common use of stevia prompted us to investigate its genotoxicity in human peripheral blood lymphocytes. Stevia (active ingredient steviol glycoside) was dissolved in pure water. Dose selection was done using ADI (acceptable daily intake) value. Negative control (pure water), 1, 2, 4, 8 and 16 μg/ml concentrations which were equivalent to ADI/4, ADI/2, ADI, ADI × 2 and ADI × 4 of Stevia were added to whole-blood culture. Two repetitive experiments were conducted. Our results showed that there was no significant difference in the induction of chromosomal aberrations and micronuclei between the groups treated with the concentrations of Stevia and the negative control at 24 and 48 h treatment periods. The data showed that stevia (active ingredient steviol glycosides) has no genotoxic activity in both test systems. Our results clearly supports previous findings.

Cytotoxicities and genotoxicities of cements based on calcium silicate and of dental formocresol.

PubMed

Ko, Hyunjung; Jeong, Youngdan; Kim, Miri

2017-03-01

Increasing interest is being paid to the toxicities of dental materials. The purpose of this study was to determine the cytotoxicities and genotoxicities of endodontic compounds to Chinese hamster ovary (CHO-K1) reproductive cells. Cultured CHO-K1 cells were treated with dental formocresol, two types of calcium hydroxide paste, and two types of mineral trioxide aggregate cement for 24h. A 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay was performed on each culture, and the micronucleus frequency was determined by performing a micronucleus assay. Alkaline comet assay and γ-H2AX immunofluorescence assay were used to detect DNA damage. Out of the five materials tested, only dental formocresol significantly increased DNA damage. The mineral trioxide aggregate cements based on calcium silicate were not found to be potentially genotoxic. The data suggest that dental formocresol should not be recommended for use in vital pulp therapy on young teeth. Copyright © 2017 Elsevier B.V. All rights reserved.

Histopathological and genotoxic effects of chlorpyrifos in rats.

PubMed

Ezzi, Lobna; Belhadj Salah, Imen; Haouas, Zohra; Sakly, Amina; Grissa, Intissar; Chakroun, Sana; Kerkeni, Emna; Hassine, Mohsen; Mehdi, Meriem; Ben Cheikh, Hassen

2016-03-01

This study aims to investigate the effects of chlorpyrifos's sub-acute exposure on male rats. Two groups with six animals each were orally treated, respectively, with 3.1 mg/kg b w and 6.2 mg/kg b w of chlorpyrifos during 4 weeks. The genotoxic effect of chlopyrifos was investigated using the comet assay and the micronucleus test. Some hematological and liver's histopathological changes were also evaluated. Results revealed that chlorpyrifos induced histopathological alterations in liver parenchyma. The lymphoid infiltration observed in liver sections and the increase in white blood cells parameter are signs of inflammation. A significant increase in the platelet' count and in polychromatic erythrocytes/normochromatic erythrocytes (PCE/NCE) ratio was observed in chlorpyrifos-treated groups which could be due to the stimulatory effect of chlorpyrifos on cell formation in the bone marrow at lower doses. In addition, the increase of bone marrow micronucleus percentage and the comet tail length revealed a genotoxic potential of chlorpyrifos in vivo.

Occurrence and Control of Genotoxins in Drinking Water: A Monitoring Proposal

PubMed Central

Ceretti, Elisabetta; Moretti, Massimo; Zerbini, Ilaria; Villarini, Milena; Zani, Claudia; Monarca, Silvano; Feretti, Donatella

2016-01-01

Many studies have shown the presence of numerous organic genotoxins and carcinogens in drinking water. These toxic substances derive not only from pollution, but also from the disinfection treatments, particularly when water is obtained from surface sources and then chlorinated. Most of the chlorinated compounds in drinking water are nonvolatile and are difficult to characterize. Thus, it has been proposed to study such complex mixtures using short-term genotoxicity tests predictive of carcinogenic activity. Mutagenicity of water before and after disinfection has mainly been studied by the Salmonella/microsome (Ames test); in vitro genotoxicity tests have also been performed in yeasts and mammalian cells; in situ monitoring of genotoxins has also been performed using complete organisms such as aquatic animals or plants (in vivo). The combination of bioassay data together with results of chemical analyses would give us a more firm basis for the assessment of human health risks related to the consumption of drinking water. Tests with different genetic end-points complement each other with regard to sensitivity toward environmental genotoxins and are useful in detecting low genotoxicity levels which are expected in drinking water samples. Significance for public health The provision of a safe drinking water is an important public health problem. Many studies have shown the presence of numerous genotoxins and carcinogens in drinking water. These toxic substances derive not only from pollution, but also from the disinfection treatments, particularly when water is obtained from surface sources and then chlorinated. The potential health risks of disinfection by-products (DBPs) from drinking water include cancer and adverse reproductive outcomes. People are exposed to disinfected drinking/shower/bathing water as a mixture of at least 600 identified DBPs and other toxic compounds via dermal, inhalation, and ingestion routes. Many of these substances are present in trace concentration, hardly detectable by chemical standard analysis. The monitoring of environmental genotoxins by short-term bioassays could allow a better evaluation of the global human exposure to water genotoxins and could help health officers and drinking water managers to reduce genotoxic hazards and distribute high quality drinking water. PMID:28083525

Lack of genotoxicity in vivo for food color additive Allura Red AC.

PubMed

Bastaki, Maria; Farrell, Thomas; Bhusari, Sachin; Pant, Kamala; Kulkarni, Rohan

2017-07-01

Allura Red AC is an approved food color additive internationally with INS number 129, in the United States as food color subject to batch certification "Food, Drug, and Cosmetic" (FD&C) Red No. 40, and in Europe as food color additive with E number 129. In their evaluation of the color (2013), the European Food Safety Authority (EFSA) expressed concerns of potential genotoxicity, based primarily on one genotoxicity study that was not conducted according to Guidelines. The present in vivo genotoxicity study was conducted according to OECD Guidelines in response to EFSA's request for additional data. The animal species and strain, and the tissues examined were selected specifically to address the previously reported findings. The results show clear absence of genotoxic activity for Allura Red AC, in the bone marrow micronucleus assay and the Comet assay in the liver, stomach, and colon. These data addressed EFSA's concerns for genotoxicity. The Joint WHO/FAO Committee on Food Additives (JECFA) (2016) also reviewed the study and concluded that there is no genotoxicity concern for Allura Red AC. Negative findings in parallel genotoxicity studies on Tartrazine and Ponceau 4R (published separately) are consistent with lack of genotoxicity for azo dyes used as food colors. Copyright © 2017 Elsevier Ltd. All rights reserved.

Lack of genotoxicity in vivo for food color additive Tartrazine.

PubMed

Bastaki, Maria; Farrell, Thomas; Bhusari, Sachin; Pant, Kamala; Kulkarni, Rohan

2017-07-01

Tartrazine is approved as a food color additive internationally with INS number 102, in the United States as food color subject to batch certification "Food, Drug, and Cosmetic" (FD&C) Yellow No. 5, and in Europe as food color additive with E number 102. In their evaluation of the color (2013), the European Food Safety Authority (EFSA) expressed concerns of potential genotoxicity, based primarily on one genotoxicity study that was not conducted according to Guidelines. The present in vivo genotoxicity study was conducted according to OECD Guidelines in response to EFSA's request for additional data. The animal species and strain, and the tissues examined were selected specifically to address the previously reported findings. The results of this study show clear absence of genotoxic activity for Tartrazine, in the bone marrow micronucleus assay and the Comet assay in the liver, stomach, and colon. These data addressed EFSA's concerns for genotoxicity. The Joint WHO/FAO Committee on Food Additives (JECFA) (2016) also reviewed these data and concluded that there is no genotoxicity concern for Tartrazine. Negative findings in parallel genotoxicity studies on Allura Red AC and Ponceau 4R (published separately) are consistent with lack of genotoxicity for azo dyes used as food colors. Copyright © 2017 Elsevier Ltd. All rights reserved.

Fecal water genotoxicity in healthy free-living young Italian people.

PubMed

Daniela, Erba; Sara, Soldi; Marcella, Malavolti; Giovanni, Aragone; Meynier, Alexandra; Sophie, Vinoy; Cristina, Casiraghi M

2014-02-01

Dietary habit affects the composition of human feces thus determining intestinal environment and exposure of colon mucosa to risk factors. Fecal water (FW) citotoxicity and genotoxicity were investigated in 33 healthy young Italian people, as well as the relationship between genotoxicity and nutrient intake or microflora composition. Two fecal samples were collected at 2 weeks apart and 3-d dietary diary was recorded for each volunteer. Cytotoxicity was measured using the Trypan Blue Dye Exclusion assay and genotoxicity using the Comet Assay (alkaline single-cell electrophoresis). Fecal bifidobacteria, total microbial count and nutrient intakes were also assessed. High intra- and inter-variability in genotoxicity data and in bacteria counts were found. None of the FW samples were citotoxic, but 90% of FW samples were genotoxic. Seventy five percent indicated intermediate and 15% were highly genotoxic. There was a different sex-related distribution. Genotoxicity was positively correlated to the total lipid intake in females and to the bifidobacteria/total bacteria count ratio in male volunteers. These results demonstrate that the majority of FW samples isolated from free-living Italian people show intermediate level of genotoxicity and sustain a relation between this possible non-invasive marker of colorectal cancer risk with both dietary habits and colonic ecosystem. Copyright © 2013 Elsevier Ltd. All rights reserved.

Adverse reactions to cosmetics and methods of testing.

PubMed

Nigam, P K

2009-01-01

Untoward reactions to cosmetics, toiletries, and topical applications are the commonest single reason for hospital referrals with allergic contact dermatitis. In most cases, these are only mild or transient and most reactions being irritant rather than allergic in nature. Various adverse effects may occur in the form of acute toxicity, percutaneous absorption, skin irritation, eye irritation, skin sensitization and photosensitization, subchronic toxicity, mutagenicity/genotoxicity, and phototoxicity/photoirritation. The safety assessment of a cosmetic product clearly depends upon how it is used, since it determines the amount of substance which may be ingested, inhaled, or absorbed through the skin or mucous membranes. Concentration of ingredients used in the different products is also important. Various test procedures include in vivo animal models and in vitro models, such as open or closed patch test, in vivo skin irritation test, skin corrosivity potential tests (rat skin transcutaneous electrical resistance test, Episkin test), eye irritation tests (in vivo eye irritancy test and Draize eye irritancy test), mutagenicity/genotoxicity tests (in vitro bacterial reverse mutation test and in vitro mammalian cell chromosome aberration test), and phototoxicity/photoirritation test (3T3 neutral red uptake phototoxicity test). Finished cosmetic products are usually tested in small populations to confirm the skin and mucous membrane compatibility, and to assess their cosmetic acceptability.

Follow-up actions from positive results of in vitro genetic toxicity testing

EPA Science Inventory

Appropriate follow-up actions and decisions are needed when evaluating and interpreting clear positive results obtained in the in vitro assays used in the initial genotoxicity screening battery (i.e., the battery of tests generally required by regulatory authorities) to assist in...

DEVELOPMENT OF A FATHEAD MINNOW MODEL FOR EVALUATING EXPOSURE OF FISH TO GENOTOXIC SUBSTANCES

EPA Science Inventory

The fathead minnow (FHM) is widely used as a standard test species for acute and chronic toxicity testing of contaminants, effluents, and receiving waters. Because of its widespread distribution throughout North America, this species also has application in monitoring studies and...

In vitro genotoxic effect of secondary minerals crystallized in rocks from coal mine drainage.

PubMed

Nordin, Adriane Perachi; da Silva, Juliana; de Souza, Claudia Telles; Niekraszewicz, Liana A B; Dias, Johnny Ferraz; da Boit, Kátia; Oliveira, Marcos L S; Grivicich, Ivana; Garcia, Ana Letícia Hilario; Oliveira, Luis Felipe Silva; da Silva, Fernanda Rabaioli

2018-03-15

Coal processing generates a large volume of waste that can damage human health and the environment. Often these wastes produce acid drainage in which several minerals are crystallized (evaporites). This study aimed to identify secondary minerals, as well as the genotoxic potential of these materials. The samples were collected at two sites along the Rocinha River in Santa Catarina state (Brazil): (1) directly from the source of the acid drainage (evaporite 1), and (2) on the river bank (evaporite 2). The samples were characterized by X-ray diffraction and by particle-induced X-ray emission techniques. In vitro genotoxicity testing using Comet assay and Micronucleus test in V79 cells was used to evaluate evaporite samples. Our study also used System Biology tools to provide insight regarding the influence of this exposure on DNA damage in cells. The results showed that the samples induced DNA damage for both evaporites that can be explained by high concentrations of chromium, iron, nickel, copper and zinc in these materials. Thus, this study is very important due to the dearth of knowledge regarding the toxicity of evaporites in the environment. The genetic toxicity of this material can be induced by increased oxidative stress and DNA repair inhibition. Copyright © 2017 Elsevier B.V. All rights reserved.

Is mobile phone radiation genotoxic? An analysis of micronucleus frequency in exfoliated buccal cells.

PubMed

de Oliveira, F M; Carmona, A M; Ladeira, C

2017-10-01

Electromagnetic fields (EMF) are classified as "possibly carcinogenic" by the International Agency for Research on Cancer (IARC). Some publications have reported associations between EMF exposure and DNA damage, but many other studies contradict such findings. Cytomorphological changes, such as micronuclei (MN), indicative of genomic damage, are biomarkers of genotoxicity. To test whether mobile phone-associated EMF exposure affects the MN frequency in exfoliated buccal cells, we obtained cells smears from the left and right inner cheeks of healthy mobile phone users, aged 18-30 (n=86), who also completed a characterization survey. MN frequencies were tested for potential confounding factors and for duration of phone use and preferential side of mobile phone use. No relationship was observed between MN frequency and duration of mobile phone use in daily calls. Cells ipsilateral to mobile phone use did not present a statistically significantly higher MN frequency, compared to cells contralateral to exposure. A highly statistically significant (p<0.0001) increase in MN frequency was found in subjects reporting regular exposure to genotoxic agents. Therefore, our results suggest that mobile phone-associated EMF do not to induce MN formation in buccal cells at the observed exposure levels. Copyright © 2017 Elsevier B.V. All rights reserved.

Exposure to bitumen fumes and genotoxic effects on Turkish asphalt workers.

PubMed

Karaman, Ali; Pirim, Ibrahim

2009-04-01

Bitumen fumes consist essentially of polycyclic aromatic hydrocarbons (PAHs) and their derivatives, some of which are known to be carcinogenic or cocarcinogenic in humans. The aim of this study was to investigate exposure to asphalt fumes among Turkish asphalt workers and determine whether any effects could be detected with genotoxic tests. The study included 26 asphalt workers and 24 control subjects. Sister chromatid exchange (SCE) and micronucleus (MN) were determined in peripheral lymphocytes. Urinary 1-hydroxypyrene (1-OHP) excretion was used as a biomarker of occupational exposure to PAHs. The asphalt workers had a significant increase in SCEs and MN (for each, p < 0.001). A positive correlation existed between the duration of exposure and rates of SCE or MN frequencies (r = 0.49, p < 0.05; r = 0.53, p < 0.05, respectively). The concentration of 1-OHP in urine was higher for the asphalt workers than for the controls (p < 0.001). However, we found that there was no statistically significant correlation between the urinary 1-OHP concentration and SCEs or MN frequencies (r = 0.25, p > 0.5; r = 0.17, p > 0.5, respectively). This study shows that Turkish asphalt workers have an increased exposure to PAHs from bitumen fumes, and genotoxic effects could be detected by SCEs and MN tests.

The genotoxic effect of oxcarbazepine on mice blood lymphocytes.

PubMed

Akbar, Huma; Khan, Ajmal; Mohammadzai, Imdadullah; Khisroon, Muhammad; Begum, Ilham

2018-04-01

This study was conducted to assess the amount of DNA damage caused by Oxcarbazepine (OXC) through single cell gel electrophoresis (SCGE) technique/comet assay. OXC derived from dibenzazepine series is an effective second generation antiepileptic drug (AED) for both children and adults. Side effects like genotoxic effects of AEDs are of prime importance resulting from toxic metabolites, free radicals and reactive oxygen species (ROS). Forty Eight adult male Bagg's albino mice (BALB/c) were randomly classified into eight groups, each comprising of six animals. Two of these groups were control and six were tested groups. Control groups were injected with 1% tween 80 while tested groups were injected with 10, 20, and 40 mg/kg-day OXC for seven days (acute therapy) and 28 days (subchronic therapy) in peritoneal cavity. Blood samples were collected by cardiac puncture and subjected to comet assay for the analysis of DNA damage. Per sample 100 cells were scored and classified according to comet tail length. The results showed that OXC in acute and long term therapies had significantly higher (p < 0.05) genotoxicity in treated groups as compared to control groups. Our study suggests that OXC may cause significant DNA damage in both acute as well as in subchronic therapies.

Association between occupational exposure to benzene and chromosomal alterations in lymphocytes of Brazilian petrochemical workers removed from exposure.

PubMed

Gonçalves, Rozana Oliveira; de Almeida Melo, Neli; Rêgo, Marco Antônio Vasconcelos

2016-06-01

We aimed to investigate the association between chronic exposure to benzene and genotoxicity in the lymphocytes of workers removed from exposure. The study included 20 workers with hematological disorders who had previously worked in the petrochemical industry of Salvador, Bahia, Brazil; 16 workers without occupational exposure to benzene served as the control group. Chromosomal analysis was performed on lymphocytes from peripheral blood, to assess chromosomal breaks and gaps and to identify aneuploidy. The Kruskal-Wallis test was used to compare the mean values between two groups, and Student's t test for comparison of two independent means. The frequency of gaps was statistically higher in and the exposed group than in the controls (2.13 ± 2.86 vs. 0.97 ± 1.27, p = 0.001). The frequency of chromosomal breaks was significantly higher among cases (0.21 ± 0.58) than among controls (0.12 ± 0.4) (p = 0.0002). An association was observed between chromosomal gaps and breaks and occupational exposure to benzene. Our study showed that even when removed from exposure for several years, workers still demonstrated genotoxic damage. Studies are still needed to clarify the long-term genotoxic potential of benzene after removal from exposure.

Use of solar advanced oxidation processes for wastewater treatment: Follow-up on degradation products, acute toxicity, genotoxicity and estrogenicity.

PubMed

Brienza, M; Mahdi Ahmed, M; Escande, A; Plantard, G; Scrano, L; Chiron, S; Bufo, S A; Goetz, V

2016-04-01

Wastewater tertiary treatment by advanced oxidation processes is thought to produce a treated effluent with lower toxicity than the initial influent. Here we performed tertiary treatment of a secondary effluent collected from a Waste Water Treatment Plant via homogeneous (solar/HSO5(-)/Fe(2+)) and heterogeneous (solar/TiO2) solar advanced oxidation aiming at the assessment of their effectiveness in terms of contaminants' and toxicity abatement in a plain solar reactor. A total of 53 organic contaminants were qualitatively identified by liquid chromatography coupled to high-resolution mass spectrometry after solid phase extraction. Solar advanced oxidation totally or partially removed the major part of contaminants detected within 4.5 h. Standard toxicity tests were performed using Vibrio fischeri, Daphnia magna, Pseudokirchneriella subcapitata and Brachionus calyciflorus organisms to evaluate acute and chronic toxicity in the secondary or tertiary effluents, and the EC50% was calculated. Estrogenic and genotoxic tests were carried out in an attempt to obtain an even sharper evaluation of potential hazardous effects due to micropollutants or their degradation by-products in wastewater. Genotoxic effects were not detected in effluent before or after treatment. However, we observed relevant estrogenic activity due to the high sensitivity of the HELN ERα cell line. Copyright © 2016 Elsevier Ltd. All rights reserved.

Lack of genotoxicity of potassium iodate in the alkaline comet assay and in the cytokinesis-block micronucleus test. Comparison to potassium bromate.

PubMed

Poul, J M; Huet, S; Godard, T; Sanders, P

2004-02-01

Iodine could be added to the diet of human population in the form of iodide or iodate but iodate had not been adequately tested for genotoxicity and carcinogenicity. In the present study, genotoxic effects of potassium iodate were evaluated in vitro using the alkaline comet assay and the cytokinesis-block micronucleus assay on CHO cells and compared to halogenate salt analogues potassium bromate and chlorate and also to their respective reduced forms (potassium iodide, bromide and chloride). The results showed that the comet assay failed to detect the presence of DNA damage after a treatment of cells by potassium iodate for concentrations up to 10 mM. This absence of primary DNA damage was confirmed in the cytokinesis-block micronucleus assay. In the same way, results showed that potassium chlorate as well as potassium iodide, bromide and chloride did not induced DNA damage in the alkaline comet assay for doses up to 10 mM. By contrast, potassium bromate exposure led to an increase in both DNA damage and frequency of micronucleated cells. The repair of bromate-induced DNA damage was incomplete 24 h after the end of treatment. These results seem to indicate that potassium bromate would induce DNA damage by several mechanisms besides oxidative stress.

Multi-walled carbon nanotubes (NM401) induce ROS-mediated HPRT mutations in Chinese hamster lung fibroblasts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rubio, Laura; El Yamani, Naouale; Kazimirova, Alena

Although there is an important set of data showing potential genotoxic effects of nanomaterials (NMs) at the DNA (comet assay) and chromosome (micronucleus test) levels, few studies have been conducted to analyze their potential mutagenic effects at gene level. We have determined the ability of multi-walled carbon nanotubes (MWCNT, NM401), to induce mutations in the HPRT gene in Chinese hamster lung (V79) fibroblasts. NM401, characterized in the EU NanoGenotox project, were further studied within the EU Framework Programme Seven (FP7) project NANoREG. From the proliferation assay data we selected a dose-range of 0.12 to 12 µg/cm{sup 2} At these rangemore » we have been able to observe significant cellular uptake of MWCNT by using transmission electron microscopy (TEM), as well as a concentration-dependent induction of intracellular reactive oxygen species. In addition, a clear concentration-dependent increase in the induction of HPRT mutations was also observed. Data support a potential genotoxic/ carcinogenic risk associated with MWCNT exposure. - Highlights: • MWCNT were tested in V79 cells. • Cellular uptake of MWCNT was detected using TEM. • Intracellular ROS induction was observed after MWCNT exposure. • MWCNT induced a concentration-dependent increase of HPRT mutations.« less