Reduction in the mutagenicity of synthetic dyes by successive treatment with activated sludge and the ligninolytic fungus, Irpex lacteus

Synthetic dyes are released in wastewater from textile manufacturing plants, and many of these dyes are genotoxic. In the present study, the mutagenicity of azo, anthraquinone, and triphenyl methane dyes was investigated before and after successive biodegradation with activated sludge and the ligninolytic fungus, Irpex lacteus. Two biodegradation systems were used to reduce the genotoxicity of dyes that were not efficiently inactivated by activated sludge alone. Mutagenicity was monitored with the Salmonella reversion assay conducted with the base-pair substitution detector strains, TA100 and YG1042, and the frame-shift detector strains, TA98 and YG1041, with and without rat liver S9. All dyes except for Congo Red (CR) were mutagenic with S9 activation. Assays conducted with the dyes indicated that only the azo dye Reactive Orange 16 (RO16) was mutagenic in both TA98 and TA100. Methyl Red and Disperse Blue 3 (DB3) were mutagenic in TA98, YG1041 and YG1042, while Reactive Black 5 was mutagenic in YG1041 and YG1042. Remazol Brilliant Blue R (RBBR), Crystal violet (CV) and Bromophenol Blue (BPB) were mutagenic only in TA98, but the toxicity of the latter two dyes complicated the evaluation of their mutagenicity. CR was not mutagenic in any of the tester strains. Biodegradation studies conducted with RO16 and DB3 indicated that the two-step biodegradation process reduced the mutagenic potential of RO16 and DB3 to a greater extent than activated sludge alone; the mutagenicity of the two dyes was reduced by 95.2% and 77.8%, respectively, by the two-step process. These data indicate that the combined biodegradation process may be useful for reducing the mutagenicity associated with wastewater from textile factories that contain recalcitrant dyes.     

Combining different assays and chemical analysis to characterize the genotoxicity of waters impacted by textile discharges

Waters receiving textile discharges can exhibit genotoxic and mutagenic activity, which has been related to the presence of dyes and aromatic amines as synthesis precursors or byproducts. The aim of this study was to identify dyes and aromatic amines in water samples impacted by textile discharges, and to evaluate the genotoxic responses of these samples using the Salmonella/microsome assay in strains TA98 and YG1041, and the Fpg‐modified comet assay in the RTL‐W1 fish cell line. The genotoxicity of river samples downstream of the discharge was greater than the upstream samples in both of the Ames tests. The Fpg‐modified comet assay detected similar levels of DNA damage in the upstream and downstream samples. Mutagenicity was not detected with TA98, except for the Quilombo River samples, but when YG1041 was used as the tester strain mutagenicity was detected for all sites with a very different profile in upstream sites relative to the other sites. The mutagenic response strongly indicated that aromatic amines or dyes were contributing to the mutagenic activity downstream. The impact of textile discharges was also confirmed by chemical analysis, because the highest concentrations of azo dyes and aromatic amines were detected in the river downstream. This study shows the value of combining assays measuring complementary endpoints to better characterize the mutagenicity of environmental samples, with the advantage that this approach provides an indication of what classes of compounds are responsible for the effect. Environ. Mol. Mutagen. 57:559–571, 2016. © 2016 Wiley Periodicals, Inc.     

High throughput image cytometry micronucleus assay to investigate the presence or absence of mutagenic effects of cold physical plasma

Promising cold physical plasma sources have been developed in the field of plasma medicine. An important prerequisite to their clinical use is lack of genotoxic effects in cells. During optimization of one or even different plasma sources for a specific application, large numbers of samples need to be analyzed. There are soft and easy‐to‐assess markers for genotoxic stress such as phosphorylation of histone H2AX (γH2AX) but only few tests are accredited by the OECD with regard to mutagenicity detection. The micronucleus (MN) assay is among them but often requires manual counting of many thousands of cells per sample under the microscope. A high‐throughput MN assay is presented using image flow cytometry and image analysis software. A human lymphocyte cell line was treated with plasma generated with ten different feed gas conditions corresponding to distinct reactive species patterns that were investigated for their genotoxic potential. Several millions of cells were automatically analyzed by a MN quantification strategy outlined in detail in this work. Our data demonstrates the absence of newly formed MN in any feed gas condition using the atmospheric pressure plasma jet kINPen. As positive control, ionizing radiation gave a significant 5‐fold increase in micronucleus frequency. Thus, this assay is suitable to assess the genotoxic potential in large sample sets of cells exposed chemical or physical agents including plasmas in an efficient, reliable, and semiautomated manner. Environ. Mol. Mutagen. 59:268–277, 2018. © 2018 Wiley Periodicals, Inc.     

Analysis of the genotoxicity of anthraquinone dyes in the mouse lymphoma assay

Despite their widespread use and potential for significant human exposure, genotoxicity data on anthraquinones and other dyes are limited. In this study, 16 anthraquinones and one azo dye (Solvent Red 1) were selected for testing using the thymidine kinase (tk) locus and micronucleus (MN) analysis in L5178Y/TK(+/-)-3.7.2C mouse lymphoma cells. Six of the dyes were from the same lot used in the NTP rodent bioassay. The dyes used were all production lots and thus varied in their purity. Disperse Blue 7, 2-aminoanthraquinone, 1-amino-2-methylanthraquinone, Disperse Blue 3 and Disperse Red 11 were genotoxic (inducing 1814 mutants/10(6) survivors, 369 MN/1000 cells at 13% survival; 397 mutants/10(6) survivors, 196 MN/1000 cells at 21% survival; 178 mutants/10(6) survivors, 119 MN/1000 cells at 51% survival; 264 mutants/10(6) survivors, 109 MN/1000 cells at 15% survival, respectively). Reactive Blue 19 was weakly mutagenic (inducing 144 mutants/10(6) survivors, but only 8 MN/1000 cells at 13% survival). Vat Yellow 4 and Solvent Red 1, with exogenous activation, were also mutagenic (inducing 300 mutants/10(6) survivors, 18 MN/1000 cells at 57% survival, and 100 mutants/10(6) survivors and 16 MN/1000 cells at 22% survival, respectively). With activation 1-nitro-2-methylanthraquinone was judged to give an equivocal mutagenicity response. The maximum test concentration was limited for some compounds by their solubility. Those chemicals that did not induce mutation or cytotoxicity at the limits of solubility were classified separately. Compounds which were not evaluated without exogenous activation because of insolubility but were evaluated with activation include 1-nitro-2-methylanthraquinone, Solvent Red 1 and Vat Yellow 4. Compounds which were not evaluated either with or without S9 activation because of their insolubility in the culture medium include 1-amino-2,4-dibromoanthraquinone, D&C Green, Disperse Blue 1, Disperse Red 60, Vat Blue 4, Vat Blue 20, Vat Brown 1 and Vat Brown 3.     

Evaluation of the mutagenicity of azo dyes in Salmonella typhimurium: a study of structure-activity relationships

In order to explore structure-activity relationships, 4,4'-diaminoazobenzene and four structurally related azo dyes were tested for their ability to induce gene mutations in Salmonella typhimurium strains TA1535, TA100, TA1537, TA1538, and TA98. Only 4,4'-diaminoazobenzene and 4,4'-N(beta-hydroxyethylamino)azobenzene were found to be active in the two frameshift strains TA1538 and TA98. Further tests were performed in strain TA98, both in the presence and in the absence of Aroclor 1254-induced rat or hamster liver S9 preparations. The amount of S9 used per plate was 50, 100, 150 or 300 microliters, which corresponds to 10, 20, 30 or 60% of S9 in S9 mix. 4,4'-Diaminoazobenzene was found to be mutagenic, and its mutagenicity depended on the percentage of S9 in S9 mix and the type of S9 fraction used. 4,4'-N-(beta-Hydroxyethylamino)azobenzene was less mutagenic than 4,4'-diaminoazobenzene, indicating a reduction in mutagenicity associated with the beta-hydroxyalkyl substituents. The other three azo dyes [4'-methyl-4-N,N-di(beta-hydroxyethylamino) azobenzene; 4'-amino-6-methyl-4-N,N-di(beta-hydroxyethylamino)azobenzene; and 4'-N(beta-hydroxyethyl-amino)4-N,N-di(beta-hydroxyethylamino)azobe nzene] were inactive, both in the presence and in the absence of the metabolic activation system. The use of the preincubation test did not alter the observed positive or negative response of these compounds. The importance of this finding is that the non-mutagenicity or decreased mutagenicity of these four compounds is predictable on the basis of their chemical structures. These azo dyes, like the non-mutagenic members of series of monocyclic aromatic amines, contain large substituents on one or both of the amino groups of the parent compound, in this case 4,4'-diaminoazobenzene. From our earlier data and the experiments discussed in this paper, we conclude that the study of structure--activity relationships can provide useful information for the prediction and interpretation of mutagenic responses.     

Role of white rot fungus Funalia trogii in detoxification of textile dyes

Toxic and genotoxic effects of the textile dyes on organisms suggest the need for remediation of dyes before discharging them into the environment. For this reason, the ability of Funalia trogii pellets to detoxify textile dyes was investigated and evaluated. Although, textile dyes are toxic substances for many microorganisms, the pellets were able to decolorize and detoxify the azo dyes used. Astrazon Blue and Red dyes inhibit growth of F. trogii and S. aureus on solid medium in a concentration dependent manner. The toxicity of these dyes on a fungus, F. trogii and a bacterium, S. aureus was significantly decreased after pretreatment with fungal pellets.     

In vitro genotoxicity of dyes present in colored smoke munitions

Genetic toxicology studies were conducted on organic dyes and mixtures used in colored smoke munitions. The dyes studied included Solvent Red 1; two different batches (Lot 1 and Lot 2) of Disperse Red 11; terephthalic acid; and a mixture of 25 parts Solvent Red 1, 5 parts Disperse Red 11, and 16 parts terephthalic acid. The dyes were evaluated for their ability to produce mutations in Salmonella bacterial strains and in Chinese hamster ovary (CHO) cells. The dyes were also tested in CHO cells to determine cytotoxicity and the induction of sister chromatid exchanges and chromosome aberration. None of the dyes were genotoxic in the standard Ames assay using bacterial strain TA1535 or TA100 with or without the addition of S-9 or in TA98 and TA1538 without S-9. With S-9, Disperse Red 11 (Lot 2) showed significant mutagenic activity in TA98 and TA1538 which increased as a function of S-9 concentration. However, the maximum level of mutagenic activity detected was low (3.8 revertants/micrograms). The azo dye Solvent Red 1 was also negative in a pre-incubation assay designed to reduce azo compounds to free amines. Solvent Red 1 was cytotoxic to mammalian cells, caused a significant increase in SCE, but was not mutagenic or clastogenic. Disperse Red 11 (Lot 1 and Lot 2) were not cytotoxic or clastogenic but produced an increase in cell cycle time and SCE frequency. Only Disperse Red 11 (Lot 2) increased mutations in the CHO/hypoxanthine-guanine phosphoribosyltransferase (HGPRT) assay. The mutagenic activity of the dye mixture was not significant, suggesting no synergistic interaction between the dyes. These studies demonstrated that none of the dyes was clastogenic and that a contaminant in Disperse Red 11 (Lot 2) may be responsible for the weak mutagenic activity in both mammalian and bacterial cell systems.     

Lack of genotoxicity of silver iodide in the SCE assay in vitro, in vivo, and in the Ames/microsome test

Silver iodide was evaluated for mutagenicity in the Ames/microsome test (strains TA 1535, TA 102, TA 97, and TA 98) and for the ability to induce Sister Chromatid Exchanges (SCE) in human cultured lymphocytes and in P388 lymphocytic leukemia cells cultured in the mouse peritoneal cavity. From the cytogenetic in vitro studies, it was observed that silver iodide, either in acetone solutions or as a suspension with polyacrilamide, scarcely causes a doubling effect on SCEs at nearly toxic concentrations (1 microg/ml). Such a doubling effect by silver iodide on SCEs in P388 leukemia cells in vivo was not achieved even after using 100 microg/g mouse body weight. In the Ames/microsome test actually a doubling effect on revertants was only isolately achieved with 30 microg/ml in TA 102 (S9-) and at 150 microg/ml in TA 97 (S9+) doses, which appear to be nearly toxic for bacteria.     

Mutagenic screening of marker grenade dyes by the Salmonella reversion assay, L5178Y/TK+/- mouse lymphoma assay, and in vivo sister chromatid exchange analysis in mice

Two dyes (C.I. Solvent Yellow No. 33 and a mixture of C.I. Solvent Yellow No. 33 and C.I. Solvent Green No. 3) were tested for mutagenicity in the Salmonella reversion assay and the L5178Y/TK+/- mouse lymphoma assay, and also for sister chromatid exchange (SCE) induction in vivo in C57B1/6J mice. In addition, a greater than 99.9% pure sample of the yellow dye [2-(2'-quinolyl)-1,3-indandione] was tested with and without exogenous activation in the Salmonella reversion assay and the L5178Y/TK+/- mouse lymphoma assay. Neither C.I. Solvent Yellow No. 33 nor the C.I. Solvent Yellow No. 33 and Solvent Green No. 3 mixture was positive for inducing SCEs in vivo. All three dyes were tested in the standard plate incorporation test in seven Salmonella strains TA98, TA100, TA102, TA104, TA1535, TA1537, and TA1538. The dyes were negative with and without exogenous activation in TA98, TA1535, and TA1538. One test with TA1537 was positive with the greater than 99.9% purified yellow dye. All three dyes gave weakly positive results (less than a twofold increase) with S-9 in TA100 and were clearly positive in TA102 and TA104 both with and without S-9. They also induced mutation at the thymidine kinase locus in mouse lymphoma cells, produced both large- and small-colony trifluorothymidine-resistant mutants, and were clastogenic. The purified yellow dye was further tested for SCE induction in mouse lymphoma cells and was determined to give a slightly positive response in the presence of S-9.     

Micronuclei induced by aneugens and clastogens in mononucleate and binucleate cells using the cytokinesis block assay

The human in vitro micronucleus (MN) test has become a fast and reliable assay for mutagenicity testing. Currently, this assay is mostly performed with cytochalasin B, which prevents cytokinesis, resulting in polynucleated cells. The number of nuclei per cell indicates the number of nuclear divisions that have occurred since the addition of cytochalasin B. It is recommended that MN are only counted in binucleated lymphocytes, because these cells have finished one nuclear division. Therefore, almost no attention has been paid to MN in mononucleated cells. However, recent studies have indicated that aneugens, but not clastogens, also induce MN in mononucleates. In order to evaluate mononucleates to distinguish between aneugenic and clastogenic effects, we tested some typical aneugens and clastogens in whole blood lymphocyte cultures of four donors with the cytokinesis block micronucleus (CBMN) assay. Results showed that the aneugens diethylstilbestrol (80 microM), griseofulvin (25 microg/ml) and vincristine sulphate (15 microg/ml) increased MN frequencies in mononucleated and binucleated cells, whilst the clastogens mitomycin C (500 ng/ml), bleomycin (6 microg/ml) and doxorubicin (20 microg/ml) increased MN frequency only in binucleates. We also tested the Y heterochromatin decondensing drug berenil (300 microg/ml). Berenil induced an extremely high number of MN in mononucleated as well as in binucleated cells, indicating an aneugenic action. This was confirmed by centromere labelling. The results suggest that MN in mononucleates may be an interesting additional parameter in the CBMN assay. Future studies should clarify whether the micronucleated mononucleate cells have escaped the cytokinesis block and become polyploid.     

Evaluation of biotoxicity of textile dyes using two bioassays

The toxicity of eight textile dyes was evaluated using two bioassays namely: Ames test and seed germination test. The Ames test is widely used for the evaluation of hazardous mutagenic effect of different chemicals, as a short-term screening test for environmental impact assessment. The eight-textile dyes and Eithidium bromide dye (as positive control) were tested with five "his" Salmonella typhimurium strains: TA 100; TA 98; TA 1535; TA 1537; TA 1538. Using six concentrations of each dye (2.5 microg/ml, 4.5 microg/ml, 9 microg/ml, 13.5 microg/ml, 18 microg/ml, and 22.5 microg/ml) revealed that, most of the dyes were mutagenic for the test strains used in this study. The high concentrations of dye eliminated microbial colonies due to the high frequency of mutation causing lethal effect on the cells.In this work the phytotoxicity of different soluble textile dyes was estimated by measuring the relative changes in seed germination of four plants: clover, wheat, tomato and lettuce. The changes in shooting percentages and root length as affected by dye were also measured. Seed germination percent and shoot growth as well as root length were recorded after 6 days of exposure to different concentrations of textile dyes in irrigation water. The results show that high concentrations of dyes were more toxic to seed germination as compared with the lower concentrations. However, the low concentrations of the tested dyes adversely affected the shooting percent significantly.     

Genotoxicity of p-nitrocinnamaldehyde and related alpha, beta-unsaturated carbonyl compounds in two bacterial assays

Seventeen cinnamaldehydes, cinnamic acids, 2-furylacroleins and related compounds were tested in the Salmonella preincubation reversion assay and in the SOS chromotest. Of eight compounds containing nitrogroups, seven were clearly mutagenic in the presence of S9 mix and six in its absence; whereas none of the parent compounds not containing a nitrogroup and none of the congeners containing chlorine, methoxy or amino groups were mutagenic. Metabolic epoxidation was excluded in additional experiments using SKF525, an inhibitor of mono-oxygenases, and trichloropropene oxide, an inhibitor of epoxide hydrolases. Less or no mutagenicity was found in the nitroreductase deficient strains Salmonella typhimurium TA100NR or TA98NR and in the O-acetyltransferase deficient strains TA100/1,8-DNP6 or TA98/1,8-DNP6 except with 5-nitro-2-furylacrolein which exhibited decreased mutagenicity in TA100NR when compared with TA100 but the highest mutagenicity in TA100/1,8-DNP6. Less or no genotoxic activity was found in the SOS chromotest when using the nitroreductase deficient Escherichia coli strain PQ253 whereas all seven compounds tested were positive in strain PQ37. The results demonstrate the importance of the nitro group and that the compounds are activated either by bacterial nitroreductase or by the nitroreductase in the S9 mix. A chemical activation of the acrolein moiety by the negative inductive effect of the nitro group is unlikely. The genotoxicity of the cinnamyl compounds is dependent on the position of the nitro group in the phenyl ring. The genotoxicities of the p-nitro compounds were about two orders of magnitude higher than those of the ortho and meta congeners. The comparison between the Ames test and the SOS chromotest showed good agreement.     

Fumonisin B(1) is genotoxic in human derived hepatoma (HepG2) cells

Fumonisin B(1) (FB(1)), a widespread Fusarium toxin which is frequently found in corn, causes liver tumors in laboratory rodents and is a suspected human carcinogen. The compound was tested in micronucleus (MN) and single cell gel electrophoresis (SCGE) assays in human derived hepatoma (HepG2) cells and caused a pronounced dose-dependent genotoxic effect at exposure concentrations > or = 25 microg/ml. In contrast, no induction of his(+) revertants was found in Salmonella microsome assays with strains TA98, TA100, TA102, TA1535 and TA1537 upon addition of HepG2-derived enzyme (S9) mix in liquid incubation assays with identical exposure concentrations. Taken together, our results indicate that FB(1) is clastogenic in human derived cells. This observation supports the assumption that this compound may act as a genotoxic carcinogen in humans.     

Effect of some phthalate esters in human cells in the comet assay.

Phthalate esters are among the most extensively used industrial chemicals and are widely distributed in the environment. Di-(2-ethylhexyl)phthalate (DEHP) and its hydrolysis product mono-(2-ethylhexyl)phthalate (MEHP) have been examined for genotoxic activity on previous occasions. Only MEHP was found to cause chromosome damage in CHO cells but was without effect in the sister chromatid exchange and hypoxanthine guanine phosphoribosyl assay. DEHP was found to be a weak direct acting mutagen in Salmonella typhimurium strain TA100, the mutagenic activity of which could be abolished by rat liver microsomes (S9 mix). The clastogenicity and weak mutagenicity suggest a possible contributory role for these compounds in the observed carcinogenicity of the phthalates, which have been thought predominantly to be linked to cancer pathology through proliferation of hepatic peroxisomes. The present study showed that these compounds could produce DNA damage in human blood cells in the Comet assay and also, that rat liver microsomes could abolish the effect of DEHP. Thus in the intact animal, no response may be observed.     

Testing of sunset yellow and orange II for genotoxicity in different laboratory animal species

The azo dyes Sunset Yellow and Orange II were gavaged to rodent species to check bile, urine, and fecal extracts for possible mutagenic activity in the Ames test or in bone marrow cells for clastogenicity using cytogenetic test systems. After oral application the dyes showed a negative response in bile, excrements, and bone marrow. When an exogenous metabolic activation was performed, increased revertant numbers using Salmonella strain TA100 were obtained only in fecal extracts of Sunset Yellow-treated animals. It is concluded that no genotoxic harm is to be expected from the ingestion of Sunset-Yellow or Orange II.     

Mutagenicity of resin acids identified in pulp and paper mill effluents using the salmonella/mammalian-microsome assay

Ten resin acids which have been identified as constituents of pulp and paper mill effluents have been examined for potential mutagenicity in the Salmonella/mammalian-microsome assay. Only neoabietic acid has been found to be mutagenic. Neoabietic acid showed dose-related increases in mutagenicity in strains TA1535, TA100, TA1538, and TA98, but not in strain TA1537. Metabolic activation with a preparation of Aroclor 1254-induced liver homogenate (S9) slightly reduced the mutagenic responses. Negative responses were found for abietic acid, dehydroabietic acid, levopimaric acid, 7-oxodehydroabietic acid, monochlorodehydroabietic acid, dichlorodehydroabietic acid, pimaric acid, isopimaric acid, and sandaracopimaric acid.     

Genotoxic activity of five haloacetonitriles: comparative investigations in the single cell gel electrophoresis (comet) assay and the ames-fluctuation test

Halogenated acetonitriles (HANs) are known to be water disinfectant by-products. Their mutagenicity and carcinogenicity have been shown in different test systems in vivo and in vitro. They also have clastogenic properties. In this study, the ability of HAN to induce single-strand breaks on the DNA of HeLa S3 cells was investigated using the single-cell gel electrophoresis (SCGE) assay, which could be a good tool with which to evaluate the genotoxicity of chlorinated water. The results were compared to those obtained in the Ames fluctuation test using the Salmonella typhimurium TA 100 strain without activation. With the Ames fluctuation test, a mutagenic effect was observed for chloroacetonitrile (MCAN), dichloroacetonitrile (DCAN), and trichloroacetonitrile (TCAN). No mutagenic effect was found with bromoacetonitrile (MBAN) or dibromoacetonitrile (DBAN). In the SCGE assay, all five HANs induced DNA damage in HeLa S3 cells, increasing the mean tail moment significantly. For each compound, a dose-effect relation was observed. This study shows that the SCGE assay has greater sensitivity for assessing the genotoxicity of HAN than does the Ames-fluctuation test. Brominated acetonitriles were more genotoxic than chlorinated acetonitriles in the SCGE assay, and the genotoxicity increased with the number of halogenated atoms of the compound. This behavior had already been found with other genotoxicity tests.     

Mutagenicity of resin acids identified in pulp and paper mill effluents using the Salmonella/mammalian-microsome assay.

Ten resin acids which have been identified as constituents of pulp and paper mill effluents have been examined for potential mutagenicity in the Salmonella/mammalian-microsome assay. Only neoabietic acid has been found to be mutagenic. Neoabietic acid showed dose-related increases in mutagenicity in strains TA1535, TA100, TA1538, and TA98, but not in strain TA1537. Metabolic activation with a preparation of Aroclor 1254-induced liver homogenate (S9) slightly reduced the mutagenic responses. Negative responses were found for abietic acid, dehydroabietic acid, levopimaric acid, 7-oxodehydroabietic acid, monochlorodehydroabietic acid, dichlorodehydroabietic acid, pimaric acid, isopimaric acid, and sandaracopimaric acid.     

Mutagenicity of carbon tetrachloride and chloroform in Salmonella typhimurium TA98, TA100, TA1535, and TA1537, and Escherichia coli WP2uvrA/pKM101 and WP2/pKM101, using a gas exposure method

The volatile solvents carbon tetrachloride and chloroform are carcinogens that are often reported as nonmutagenic in bacterial mutagenicity assays. In this study, we evaluated the mutagenicity of these compounds in Salmonella typhimurium TA98, TA100, TA1535, and TA1537, and Escherichia coli WP2uvrA/pKM101 and WP2/pKM101, with and without S9 mix, using a gas exposure method. Tests were also conducted with a glutathione-supplemented S9 mix. Carbon tetrachloride was mutagenic in TA98 without S9 mix, and in WP2/pKM101 and WP2uvrA/pKM101 with and without S9 mix; carbon tetrachloride was not mutagenic in TA100, TA1535 or TA1537. Chloroform was mutagenic in WP2/pKM101, but only in the presence of glutathione-supplemented S9 mix. Chloroform was not mutagenic in TA98, TA100, TA1535, TA1537, or WP2uvrA/pKM101 with or without S9 mix, and was not mutagenic in TA98, TA100, TA1535, TA1537, or WP2uvrA/pKM101 in the presence of glutathione-supplemented S9 mix. The data indicate that carbon tetrachloride and chloroform are bacterial mutagens when adequate exposure conditions are employed and suggest that a genotoxic mode of action could contribute to the carcinogenicity of these compounds.     

Mutagenic potential of bisphenol A diglycidyl ether (BADGE) and its hydrolysis-derived products in the Ames Salmonella assay.

The mutagenicity of bisphenol A diglycidyl ether (BADGE), its first and second hydrolysis products (the diol epoxide and bis-diol of BADGE, respectively) and the bis-chlorohydrin of BADGE were investigated using the Ames Salmonella assay with strains TA98, TA100, TA1535 and TA1537. The assays were performed in the absence and presence of various concentrations of rat liver S9 fraction. The results obtained confirm the mutagenic power of BADGE in strains TA100 and TA1535 and show a positive response to the diol epoxide of BADGE in these strains, although the latter compound was approximately 10 times less potent than the former. A lack of mutagenic activity of the bis-diol of BADGE and the chlorohydrin under study is also shown. These findings suggest that BADGE and, to a much lesser extent, the diol epoxide of BADGE may constitute a genotoxic hazard, but not the bis-diol or bis-chlorohydrin of BADGE.