Environmental tobacco smoke: comparative characterization by mutagenicity assays of sidestream and mainstream cigarette smoke

Mainstream cigarette smoke particles were collected by means of a smoking machine, and sidestream particles were collected from the room in which the smoking took place. The particles were extracted by sonication with acetone, and the extracts were solvent-exchanged to dimethyl sulfoxide. The samples were tested for mutagenicity in the Ames Salmonella/microsome assay. The mainstream extract is preferentially mutagenic in the presence of S9, with about 30,000 revertants/cigarette in TA98, but has little or no activity in its absence. The sidestream extract is also mutagenic in the presence of S9 with TA98, and this activity is mainly due to basic compounds. Sidestream smoke is also significantly mutagenic in the absence of S9 in the strain TA100 as well as in TA97 and TA104. This "direct" activity is due to components that are labile. The response of sidestream particles is 10,000-20,000 revertants/cigarette in TA98 + S9 and TA100-S9 when the collection is performed in a room where the particle concentration is modulated by deposition to surfaces. Sidestream particles collected on glass fiber filter and by electrostatic precipitation (ESP) with a commercial air cleaning device gave essentially the same mutagenic response, showing that ESP sampling may be an alternative to filter sampling for environmental tobacco smoke (ETS) in indoor environments. ESP sampling in children's rooms in smoking and nonsmoking homes showed that 5-10% of the tobacco smoke emitted in the smoking homes entered the child's room, demonstrating that diffusion of pollutants is faster than ventilation in modern buildings with low ventilation rates.     

A preliminary characterization of the mutagenicity of atmospheric particulate matter collected during sugar cane harvesting using the Salmonella/microsome microsuspension assay

During sugar cane harvesting season, which occurs from May to November of each year, the crops are burnt, cut, and transported to the mills. There are reports showing that mutagenic activity and PAH content increase during harvesting season in some areas of São Paulo State in comparison with nonharvesting periods. The objective of this work was to preliminarily characterize the mutagenic activity of the total organic extracts as well as corresponding organic fractions of airborne particulate matter (PM) collected twice from two cities, Araraquara (ARQ) and Piracicaba (PRB), during sugar cane harvesting season using the Salmonella/microsome microssuspension assay. One sample collected in São Paulo metropolitan area was also included. The mutagenicity of the total extracts ranged from 55 to 320 revertants per cubic meter without the addition of S9 and from not detected to 57 revertants per cubic meter in the presence of S9 in areas with sugar cane plantations. Of the three fractions analyzed, the most polar ones (nitro and oxy) were the most potent. A comparison of the response of TA98 with YG1041 and the increased potencies without S9 indicated that nitro compounds are causing the observed effect. More studies are necessary to verify the sources of the mutagenic activity such as burning of vegetal biomass and combustion of heavy duty vehicles used to transport the sugar cane to the mills. The Salmonella/microsome assay can be an important tool to monitor the atmosphere for mutagenicity during sugar cane harvesting season. Environ. Mol. Mutagen. 2008. © 2008 Wiley‐Liss, Inc.     

Mutagenic activity of carbon black dyes used in the leather industry

Seven carbon black pastes used as commercial leather dyes weretested for their mutagenicity in the Salmonella/microsome test(TA98 and TA100 strains). All the samples assayed either directlyor after extraction with a 30-min sonication in benzene weredevoid of mutagenicity both in the presence and absence of ametabolic activation preparation. After a 48-h extraction withboiling toluene in a Soxhlet apparatus, four samples were mutagenicin TA98 strain in the presence of S9 mix. The activity rangedfrom 1.3 to 9.6 induced revertants/mg equivalent of extract.A weak direct mutagenic activity in strain TA98 was shown byone extract. Polycyclic aromatic hydrocarbons (PAH) were determinedin the toluene extracts by high resolution gas chromatography/massspectrometry. The presence of PAH could explain the mutagenicityof only one sample (8.79 µg of total PAH/100 mg equivalentsof extract), while low or undetectable levels of PAH were foundin the other mutagenic extracts. The mutagenic activity wasevident only after a vigorous extraction process, thus a lowbioavailability of the mutagens present in these compounds issuggested. ²To whom correspondence should be addressed     

Comparative mutagenicity of a coal combustion fly ash extract in Salmonella typhimurium and Chinese hamster ovary cells

The dichloromethane extract of a coal combustion fly ash sample obtained from an experimental fluidized bed coal combustor was tested for mutagenicity in Salmonella typhimurium and cultured Chinese hamster ovary (CHO) cells. The extract was directly mutagenic in S typhimurium strain TA98 and the nitroreductase deficient strains TA98NR and TA98/1,8DNP6. The mutagenicity observed in TA98NR and TA98/1,8DNP6 was lower than that in TA98. Addition of exogenous Aroclor 1254-induced rat liver supernatant (liver S9) decreased the bacterial mutagenicity of the extract. A different mutagenic response was observed in CHO cells. In the absence of liver S9, although the extract was cytotoxic to CHO cells, no significant mutagenicity was observed. Addition of exogenous liver S9 decreased the cytotoxicity and increased the mutagenicity at both Na+-K+-ATPase and hypoxanthine-guanine phosphoribosyl transferase (HGPRT) gene loci in CHO cells. Using gas chromatography/mass spectrometry (GC/MS) and tandem quadruple mass spectrometry, a number of polynuclear aromatic hydrocarbons (PAHs) and nitrated PAHs (nitro-PAHs) were tentatively identified and quantitated. A possible explanation of the difference in bacterial and mammalian mutagenicity of the extract is that the bacterial mutagenicity was induced by the nitro-PAHs that are potent bacterial mutagens and mammalian mutagenicity was induced by both PAHs and nitro-PAHs that are promutagens.     

Genotoxicity of nitrosulfonic acids, nitrobenzoic acids, and nitrobenzylalcohols, pollutants commonly found in ground water near ammunition facilities

2-Amino-4,6-dinitrobenzoic acid (2-A-4,6-DNBA), 4-amino-2,6-dinitrobenzoic acid (4-A-2,6-DNBA), 2,4,6-trinitrobenzoic acid (2,4,6-TNBA), 2-amino-4, 6-dinitrobenzylalcohol (2-A-4,6-DNBAlc), 4-amino-2,6-dinitrobenzylalcohol (4-A-2,6-DNBAlc), 2,4-dinitrotoluol-5-sulfonic acid (2,4-DNT-5-SA), 2,4-dinitrotoluol-3-sulfonic acid (2,4-DNT-3-SA), and 2, 4-dinitrobenzoic acid (2,4-DNBA) are derivatives of nitro-explosives that have been detected in groundwater close to munitions facilities. In the present study, the genotoxicity of these compounds was evaluated in Salmonella/microsome assays (in strains TA100 and TA98, with and without S9 and in TA98NR without S9), in chromosomal aberration (CA) tests with Chinese hamster fibroblasts (V79), and in micronucleus (MN) assays with human hepatoma (HepG2) cells. All compounds except the sulfonic acids were positive in the bacterial mutagenicity tests, with 2,4,6-TNBA producing the strongest response (8023 revertants/micromol in TA98 without S9 activation). 2-A-4,6-DNBA was a direct acting mutagen in TA98, but negative in TA100. The other positive compounds were approximately 1-3 orders of magnitude less mutagenic than 2,4,6-TNBA in TA98 and in TA100; relatively strong effects ( approximately 50-400 revertants/micromol) were produced by the benzylacohols in the two indicator strains. With the exception of 2,4-DNBA, the mutagenic responses were lower in the nitroreductase-deficient strain TA98NR than in the parental strain. 2,4-DNBA produced a marginally positive response in the V79-cell CA assay; the other substances were devoid of activity. Only the benzoic acids were tested for MN induction in HepG2 cells, and all produced positive responses. As in the bacterial assays, the strongest effect was seen with 2,4,6-TNBA (significant induction at >or=1.9 microM). 4-A-2,6-DNBA was positive at 432 microM; the weakest effect was observed with 2,4,-DNBA (positive at >or=920 microM). The differences in the sensitivity of the indicator cells to these agents can be explained by differences in the activities of enzymes involved in the activation of the compounds. The strong responses produced by some of the compounds in the human-derived cells suggest that environmental exposure to these breakdown products of nitro-explosives may pose a cancer risk in man.     

Role of nitroreduction in the synergistic mutational response induced by mixtures of 1- and 3-nitrobenzo[a]pyrene in Salmonella typhimurium

Previous studies showed that binary mixtures of the environmental pollutants 1- and 3-nitrobenzo[a]pyrene produced a synergistic mutational response in the Salmonella reversion assay. Since nitroreduction is believed to mediate the direct-acting mutagenicity of the individual compounds, we have examined the role of nitroreduction in the mutagenicity of mixtures of 1- and 3-nitrobenzo[a]pyrene in the Salmonella plate incorporation assay. While mixtures of 1- and 3-nitrobenzo[a]pyrene induced up to 183% more revertants in strain TA98 than produced by equivalent amounts of the individual compounds, in the nitroreductase-deficient strain TA98NR the same mixtures only induced up to 57% more revertants than the individual compounds. Analysis of mixtures of 1- and 3-nitrosobenzo[a]pyrene (the two-electron reduction products of 1- and 3-nitrobenzo[a]pyrene) for mutation induction in TA98 yielded no evidence of a synergistic effect between the compounds. The mutagenicity of the mixtures was dependent upon the amount of the more mutagenic component. Salmonella cultures were also incubated with mixtures of 1- and 3-nitrobenzo[a]pyrene, as well as with equivalent amounts of the individual compounds. In two experiments, nitroreductive ability, as measured by the amount of 1-nitropyrene metabolized to 1-aminopyrene in 1 hr, was increased 9 to 105% in cultures pretreated with the mixtures as compared with cultures pretreated with the individual compounds. The results of this study support the hypothesis that nitroreduction is a major factor in the synergistic mutational response induced by 1- and 3-nitrobenzo[a]pyrene in Salmonella typhimurium.     

Mutagenicity and antimutagenicity of hispidulin and hortensin, the flavonoids from Millingtonia hortensis L.

Studies of the mutagenicity and antimutagenicity of hispidulin and hortensin, the flavonoids from Millingtonia hortensis L. (Bignoniaceae), were performed using the liquid preincubation method of the Salmonella/microsome test. At the highest dose tested, 100 micrograms/plate, both compounds showed no mutagenicity and no cytotoxicity toward S. typhimurium strains TA98 and TA100 either in the presence or absence of S9 mix. However, these substances were antimutagens toward 2-aminoanthracene, aflatoxin B1 (in TA98), and dimethylnitrosamine (in TA100); but neither substance inhibited the direct mutagenic activity of 2-(2-furyl)-3-(5-nitro-2-furyl) acrylamide nor that of sodium azide in strains TA98 and TA100, respectively.     

Some findings on mutagenicity in airborne particulate pollutants

Mutagenic activity in particulate airborne pollutants in several samples collected in a wide variety of industrial, residential, and small-scale factory districts over the past seven years was detected by the Ames test. The particulate air samples that were not contaminated with several chemicals such as NO (less than 0.001 ppm), NO2 (less than 0.001 ppm), and SO2 (less than 0.001 ppm) showed only low mutagenic activity (1 revertant/m3) when they were tested with Salmonella typhimurium strain TA98 in the presence of S9 mix. However, most of the samples polluted by particulate matters showed high mutagenicity, with responses varying from 2.4 to 445 revertants per m3: 67 samples from an industrial area induced an average of 44 revertants per m3; 60 from a residential area, 16.2; and 10 from a small-scale factory area, 72.1. For assessing the mutagenic potential of the pollution in the atmosphere, the frequency of mutation determined with strain TA98 in the presence of S9 mix was used to divide the samples tentatively into five groups (A-E) on the basis of the normal logarithmic distribution curve of 137 samples. Air samples belonging to group A gave less than 2.3 revertants per m3 of air (1.12 +/- 0.12, no pollution); those of group B gave a range of 2.4 to 8.6 (5.93 +/- 1.91, slight pollution); those of group C gave a range of 8.7 to 30.2 (16.0 +/- 5.36, moderate pollution); those of group D gave a range of 30.3 to 115 (56.7 +/- 20.1, considerable pollution); and those of group E gave more than 116 (234 +/- 119, heavy pollution). Of the 137 samples tested, 6 samples (4.4%) were assigned to group A, 38 (27.7%) to group B, 52 (38.0%) to group C, 34 (24.8%) to group D, and 7 (5.1%) to group E. Furthermore, the samples in an industrial area were classified in the order of group C (35.8%), group B (26.9%), group D (22.4%), group E (8.96%), and group A (5.97%), and those in a residential area in the order of group C (46.7%), group B (33.3%), group D (18.3%), and group A (1.67%).     

Mutagenicity profile of atmospheric particulate matter in a small urban center subjected to airborne emission from vehicle traffic and sugar cane burning

Atmospheric particulate matter (PM) is genotoxic and recently was classified as carcinogenic to humans by the International Agency for Research on Cancer. PM chemical composition varies depending on source and atmospheric conditions. The Salmonella/microsome assay is the most used mutagenicity test and can identify the major chemical classes responsible for observed mutagenicity. The objective of this work was to characterize the mutagenicity of PM samples from a countryside city, Limeira, Brazil, which is influenced by heavy traffic and sugar cane biomass burning. Six samples of total PM were collected. Air mass backward trajectories were calculated. Organic extracts were assayed using the Salmonella/microsome microsuspension mutagenicity assay using TA98, YG1041, and TA1538, with and without metabolic activation (S9). YG1041 was the most sensitive strain and mutagenicity reached 9,700 revertants per m³ without metabolic activation. Potency for TA1538 was higher than TA98, indicating that this strain should be considered in air mutagenicity studies. The increased response to YG1041 relative to TA98, and the decreased response with S9, suggests that nitroaromatics are the major contributors. Limeira is among the most mutagenic cities in the world. High mutagenicity in Limeira seems to occur when the air mass from the area of sugarcane production is mixed with air from the region impacted by anthropogenic activities such as traffic. An increase in the formation of nitro‐polycyclic aromatic hydrocarbons may result from longer contact time between the aromatic compounds and the atmosphere with high NOx and ozone concentration, although more studies are required to confirm this hypothesis. Environ. Mol. Mutagen. 57:41–50, 2016. © 2015 Wiley Periodicals, Inc.     

Mutagenicity of lichen constituents

Usnic acid (the most abundant lichen constituents), physodic, and physodalic acids isolated from Hypogymnia enteromorph (Ach.) Nyl. were tested for mutagenicity in the Ames Salmonella/microsome assay. Physodalic acid exhibited clear dose-related mutagenicity against Salmonella typhimurium strain TA 100 with or without S9 mix in both plate-incorporation and preincubation assays. The addition of S9 mix increased the number of revertants approximately threefold and fourfold in preincubation and plate-incorporation assays, respectively.     

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.     

Mutagenicity of products from coal gasification and liquefaction in the salmonella/microsome assay

As a first step in the assessment of their possible bio-effects, coal-related materials were tested for mutagenicity in the Salmonella/microsome assay. Of three coal gasification by-products tested, only a tar was mutagenic for any of four Salmonella strains. The following liquefaction materials were mutagenic for strains TA1538, TA98, and/or TA100: A liquefaction vehicle oil and coal hydrogenation filtered liquid, separated bottoms, vacuum overhead, and vacuum bottoms. Neither powdered coal nor water produced as a by-product of the hydrogenation process was positive in the Salmonella test. No coal-related material was mutagenic for the missense mutant TA1535 or for any strain in the absence of metabolic activation provided by rat hepatic homogenates (S9). In all but one instance Aroclor 1254-induced S9 provided the maximum activation for mutagenesis. Fractionation of all samples was undertaken by serial extraction with organic solvents of increasing polarity (hexane, toluene, methylene chloride, acetonitrile). Highly mutagenic materials were found in fractions of the hydrogenation filtered liquid, vacuum overhead, and vacuum bottoms. Thus far non-mutagenic samples have not yielded mutagenic components upon fractionation.     

Mutagenicity of the organic fraction of World Trade Center dust

Most studies of the health effects and chemical characterization of the dust resulting from the catastrophic collapse of the World Trade Center (WTC) on September 11, 2001, have focused on the large inorganic fraction of the dust; however, chemical analyses have identified mutagens and carcinogens in the smaller organic fraction. Here, we determined the mutagenicity of the organic fraction of WTC dust in Salmonella. Only 0.74% of the mass of the particulate matter (PM) <53 μm in diameter was extractable organic matter (EOM). Because the EOM was 10 times more mutagenic in TA100 +S9 than in TA98 +S9 and was negative in TA98 −S9, we inferred, respectively, that polycyclic aromatic hydrocarbons (PAHs) played a role in the mutagenicity and not nitroarenes. In TA98 +S9, the mutagenic potency of the EOM (0.1 revertant/μg EOM) was within the range of EOMs from air and combustion emissions. However, the EOM-based mutagenic potency of the particles (0.0007 revertants/μg PM) was 1–2 orders of magnitude lower than values from a review of 50 combustion emissions and various air samples. We calculated that 37 PAHs analyzed previously in WTC EOM were 5.4% of the EOM mass and 0.04% of the PM mass; some air contained 0.3 μg WTC EOM/m³ (0.02 μg PAHs/m³). Populations exposed to WTC dust have elevated levels of prostate and thyroid cancer but not lung cancer. Our data support earlier estimates that PAH-associated cancer risk among this population, for example, PAH-associated lung cancer, was unlikely to be significantly elevated relative to background PAH exposures.     

Mutagenicity of Ayahuasca and Their Constituents to the Salmonella/Microsome Assay

Ayahuasca is a beverage used in religious rituals of indigenous and nonindigenous groups, and its therapeutic potential has been investigated. Ayahuasca is obtained by decoction of the Banisteriopsis caapi that contains β-carbolines (harmine, harmaline, and tetrahydroharmine) plus Psychotria viridis that contains N,N-dimethyltryptamine. Although plants used in folk medicine are recognized as safe, many of them have genotoxic potential. The Salmonella/microsome assay is usually the first line of the mutagenicity evaluation of products intended for therapeutic use. Our objective was to evaluate the mutagenicity of ayahuasca beverage and their constituents using the Salmonella/microsome assay with TA98 and TA100. We analyzed two ayahuasca samples, and also beverage samples prepared each individual plant P. viridis and B. caapi. Harmine and harmaline were also tested. All beverage samples were chemically characterized and both ayahuasca samples could be considered representative of the beverages consumed in religious rituals. Both ayahuasca samples were mutagenic for TA98 and TA100 with and without S9, with similar potencies. The beverage obtained from P. viridis was not mutagenic, and beverage obtained from B. caapi was mutagenic for TA98 with and without S9. Harmine was nonmutagenic and harmaline was mutagenic only for TA98 without S9. Harmaline fully explain the mutagenicity observed with TA98 without S9 of both ayahuasca samples and the B. caapi beverage samples. We conclude that the ayahuasca samples are mutagenic and this effect is partially explained by harmaline, one of the β-carbolines present in the beverage. Other mutagenic compounds seem to be present and need to be further investigated. Environ. Mol. Mutagen. 60:269–276, 2019. © 2018 Wiley Periodicals, Inc.     

Propyldazine is mutagenic in Salmonella typhimurium and Escherichia coli: distinct specificity for strains TA1537 and TA97

The antihypertensive drug propyldazine (Atensil) was demonstrated to be mutagenic with auxotrophic mutants of Salmonella typhimurium and Escherichia coli. Addition of liver S9 mix (postmitochondrial supernatant fraction supplemented with an NADPH-generating system) had little, if any, effect on the mutagenicity. The mutagenicity showed an unusual pattern of strain specificity. Increased frequencies of reversion were observed with all strains whose auxotrophy was caused by frame-shift mutations: the number of revertant colonies per plate from S. typhimurium TA98, TA1538, TA97, and TA1537 was increased up to 5-, 9-, 43-, and 160-fold, respectively, above background. Among the strains that became auxotrophic by substitution mutations, S typhimurium TA102, E. coli WP2, and E coli WP2 uvrA yielded positive results (twofold above background). S. typhimurium TA1535 and TA100 were not reverted by propyldazine. It should be noted that propyldazine, due to its low toxicity and good solubility, could be tested up to very high doses. Hence, although quite impressive mutagenic effects occurred, the mutagenic potency was moderate even in the most responsive strains, TA1537 and TA97 (about 0.3 and 1.0 revertants per nmole, respectively). With the limitation that the strain specificities were different, the mutagenic potency of propyldazine was in the same order of magnitude as that of hydralazine and dihydralazine, two related antihypertensive drugs which were already known to be mutagenic. In our hands, both compounds were mutagenic in S typhimurium TA1535, TA100, TA1537, and TA98. These results differ from data in the literature in that we found clear but weak effects even with strains for which others have reported negative results.     

Mutagenicity of bisphenol A (4,4'-isopropylidenediphenol) in vitro: effects of nitrosylation

Bisphenol A (4,4'-isopropylidenediphenol) is a common component of polycarbonate plastics and epoxy resins. Since bisphenol A-containing plastics and resins have found uses in food-contact items, its potential migration into foodstuffs and possible health consequences have been the focus of many recent studies. However, the potential mutagenic activation of bisphenol A by nitrosylation has received little attention. Incubation of bisphenol A with sodium nitrite under acidic conditions produced a yellow-brown product. When nitrosylated bisphenol A was tested in the Ames Salmonella/microsome assay at 100 ng to 1 mg/plate, dose-dependent increases in mutagenicity were found in both TA98 and TA100 Salmonella strains. These results indicated the presence of a direct-acting mutagenic activity causing both frameshift and base pair mutations, respectively. When compared to colony formation in untreated controls, the addition of rat liver S9 for metabolic activation had little influence on revertant colony formation. Unreacted bisphenol A dissolved in DMSO, acidic buffer, or inactivated nitrosylation solution showed negligible mutagenicity. When the nature of the mutagenic changes was examined using the Ames II trade mark Assay, a variety of base pair changes was found including T:A to A:T - S9, G:C to A:T +/- S9,C:G to A:T +/- S9 and C:G to G:C +/- S9. Bisphenol A also induced frameshift mutations at G:C sites. In addition, the presence of electrophiles was shown by the production of an intensely coloured orange-red product upon incubation of nitrosylated bisphenol A with the nucleophile 4-(4'-nitrobenzyl)pyridine. These findings suggest that migration of bisphenol A into nitrite containing foodstuffs, or its ingestion in the presence of nitrite, could lead to the formation of mutagenic compounds.     

Genotoxicity of 2-halocinnamaldehydes in two bacterial assays. Induction of SOS repair and frame-shift mutation

2-Chlorocinnamaldehyde and 2-bromocinnamaldehyde, compoundsof practical interest, for example, as bacterioddes and fungicidesor for utilization in light sensitive layers, were tested inthe Ames preincubation test with various Salmonella typhimuriumstrains, and in the SOS chromotest with Escherichia coli PQ37. 2-Chlorocinnamaldehyde was clearly mutagenic in strain TA100 (6081 revertants/µmol) and in strain TA 98 (3050 revertants/µmol)without S9 mix, and was clearly positive in the SOS chromotest(SOSIP = 0.181). 2-Bromocinnamaldehyde was a strong mutagenin strain TA 100 (105, 500 revertants/µmol), in strainTA98 (41567 revertants/µmol) and in strain TA 1538 (15825revertants/ µmol), and also unambiguously mutagenic instrain TA 1535 (2110 revertants/µmol) without S9 mix.The SOSIP in the SOS chromotest was 1.5. Addition of S9 mixled to a marked decrease in the mutagenic activity of 2-bromocinnamaldehydein all strains tested. In the case of strain TA 1535, mutagenicactivity was abolished or not significant in the presence ofS9 mix. The possible primary mechanisms underlying these mutageniceffects are discussed. Frame-shift activity of these halocinnamaldehydescan be explained by their planar structure. ¹To whom correspondence should be addressed     

Mutagenicity,antioxidant potential,and antimutagenic activity against hydrogen peroxide of cashew (Anacardium occidentale) apple juice and cajuina

Fresh and processed cashew (Anacardium occidentale) apple juice (CAJ) are among the most popular drinks in Brazil. Besides their nutritional benefits, these juices have antibacterial and antitumor potential. The chemical constituents of both the fresh juice and the processed juice (cajuina) were analyzed and characterized as complex mixtures containing high concentrations of vitamin C, various carotenoids, phenolic compounds, and metals. In the present study, these beverages exhibited direct and rat liver S9-mediated mutagenicity in the Salmonella/microsome assay with strains TA97a, TA98, and TA100, which detect frameshifts and base pair substitution. No mutagenicity was observed with strain TA102, which detects oxidative and alkylating mutagens and active forms of oxygen. Both CAJ and cajuina showed antioxidant activity as determined by a total radical-trapping potential assay. To test whether this antioxidant potential might result in antimutagenesis, we used a variation of the Salmonella/microsome assay that included pre-, co-, and posttreatment of hydrogen peroxide-exposed Salmonella typhimurium strain TA102 with the juices. CAJ and cajuina protected strain TA102 against mutation by oxidative damage in co- and posttreatments. The antimutagenic effects during cotreatment with hydrogen peroxide may be due to scavenging free radicals and complexing extracellular mutagenic compounds. The protective effects in posttreatment may be due to stimulation of repair and/or reversion of DNA damage. The results indicate that CAJ and cajuina have mutagenic, radical-trapping, antimutagenic, and comutagenic activity and that these properties can be related to the chemical constituents of the juices.     

Mutagenicity of airborne particles from a nonindustrial town in Italy

The mutagenic activity of airborne particulate matter collected in Pisa, a small nonindustrial town located in Italy, has been monitored over 1 year using the Ames Salmonella Test. Airborne particulate was collected on fibreglass filters using a Hi-Vol sampler and extracted by sonication and Soxhlet acetone extraction in sequence. TA 98 and TA 100 salmonella strains gave positive results with the great majority of samples. The mutagenicity trend fits with a harmonic regression with a peak during December/January and inversely correlates with the temperature. No correlations were observed with other meteorological conditions such as wind, cloud, rainfall, atmospheric pressure, and humidity. The ratio between mutagenicity/microgram of particulate matter with S9 and that without S9 remains more or less constant regardless of seasonal fluctuations, suggesting that during cold months quantitative increases of mutagens onto particulate matter have probably occurred. The comparison of air mutagenicity in different sites suggests that motor vehicle exhaust fumes are the major source of air pollution. Finally, because of high-traffic volume, air mutagenicity at street level is comparable to that observed in several metropolitan areas all over the world.     

Mutagenic potentials of dental cements as detected by the Salmonella/microsome test

The potential mutagenicity of a zinc phosphate (Poscal), a polycarboxylate (Aqualox) and glass ionomer cements with (Argion) and without (Meron) silver reinforcement were characterized by employing the Ames Salmonella/microsome test. The materials were eluted in dimethyl sulphoxide or physiologic saline and the aliquots were used either immediately or after an incubation period of 24h at 37 degrees C. Mutagenic effects of the materials were tested on Salmonella typhimurium strains TA 98, TA 100, TA 102 and TA 1535 using the standard plate incorporation assay, and in the presence or absence of S9 fraction from rat liver. Poscal and Aqualox elicited mutagenic effects on S. typhimurium TA 98 and TA 1535, whereas Meron exhibited mutagenic effects on S. typhimurium TA 98. No mutagenic effects were detected for Argion. The type of solvent, dose of the material and incubation as well as the interactions between these factors exhibited varying degrees of influences on the mutagenic activities of the cements (P<0.05 and P<0.1). We conclude that zinc phosphate, polycarboxylate, and glass ionomer cements may have possible mutagenic activities.