Mutagenicity and clastogenicity of gas stove emissions in bacterial and plant tests

The aim of this research was to study the gaseous and particulate emissions of genotoxic substances during cooking with two types of methane stoves (a new one and an old one). The particulates were sampled both with a cascade impactor air sampler and an impinger with ice trap and analyzed by two bacterial mutagenicity tests (Ames and Kado tests) and by HPLC for polycyclic aromatic hydrocarbons (PAH). Gaseous emissions were studied in situ using the Ames test, a clastogenicity plant test (Tradescantia-micronucleus test), and in an automated system for chemical analyses. Clear indirect mutagenicity was found only with the Kado test (TA98-S9) in extracts of particulates emitted from the old methane stove and collected with the impinger. Similar mutagenicity (TA98+S9) was also found for the finest fraction of particulates (<0.5 um) collected from both stoves. Gaseous emissions of both stoves caused clastogenicity in the in situ experiments with the Tradescantia-micronucleus test. The physico-chemical analyses of the emissions showed also the presence of very fine particulates and trace amounts of PAH. The exposure of these genotoxins could be particularly important for occupationally exposed individuals in homes and businesses and for susceptible subjects living indoors for long periods (infants, children, the sick, and the elderly). Environ. Mol. Mutagen. 31:402–408, 1998. © 1998 Wiley-Liss, Inc.     

In vitro genotoxicity potential investigation of 7 oxy-PAHs

Air pollutants include many compounds among them oxygenated polycyclic aromatic hydrocarbons (oxy-PAHs). As they are suspected to generate DNA damage and mutagenicity, an understanding of their mode of action could highlight a carcinogenic potential risk in exposed population. In this article, a prospective study on seven oxy-PAHs selected in terms of occurrence in the environment was conducted on mutagenicity, genotoxicity, and cytotoxicity potentials using in vitro assays including Ames test on five strains, kinetic analysis of cytotoxicity and apoptosis, phosphorylation of histone H2AX, and p53 induction assays on human lung cell line BEAS-2B. Ames test demonstrated that mutagenicity pattern depended on the oxy-PAH tested. Except for BAQ, all oxy-PAHs tested gave mutagenic effect, in the absence and/or in the presence of metabolic activation (S9 fraction). At 24 h of exposure, the majority of oxy-PAHs induced γ-H2AX in BEAS-2B cells and/or phosphorylation of p53 at serine 15 and cell death at highest tested concentrations. Although 9,10-AQ and B[b]FO were mutagenic in bacteria, they failed to induce any of the other genotoxicity biomarkers. In comparison with the benzo[a]pyrene, all oxy-PAHs were less potent in terms of genotoxic potential at the same concentration. These results highlighted the genotoxic and mutagenic potential of these oxy-PAHs and provide preliminary information concerning their possible mechanism of action for toxicity, contributing to a better evaluation of the real associated health risks for human and environment.     

Genotoxic and reproductive effects of an industrially contaminated soil on the earthworm Eisenia Fetida

Polluted soil sampled from a former coking plant in Lorraine (France) was studied for its genotoxicity and reproductive effects on the Eisenia fetida earthworm. Genotoxicity was investigated by means of the single‐cell gel electrophoresis (comet) assay on the coelomocytes of earthworms after 4 and 10 days of exposure to the soil. DNA damage and a decline in the number of coelomocytes extruded from earthworms were observed at coking plant soil concentrations of 20 and 40% (w/w) in ISO soil. These soil concentrations had previously been shown to significantly reduce cocoon and juvenile productions after 28 and 56 days of earthworm exposure, respectively. The results showed that genotoxic pollutants in the tested soil were still bioavailable despite the age of the contaminated soil. Similar values of the no‐observed‐effect concentration (NOEC) corresponding to 10% of the contaminated soil and of the lowest soil concentration tested inducing effects (LOEC) corresponding to 20% of the contaminated soil were obtained from reproductive and genotoxicity endpoints. Among the soil pollutants measured, polycyclic aromatic hydrocarbons (PAHs) appeared to be the most likely source of the genotoxicity recorded, although effects of metals could not be excluded. Measurement of genotoxicity in earthworms could complement the existing standardized tests used in the ecotoxicological assessment of the risk associated with contaminated soils. Environ. Mol. Mutagen., 2009. © 2008 Wiley‐Liss, Inc.     

Mutagenicity of effluents from an experimental fluidized bed coal combustor

The fluidized bed combustion of coal, a low-temperature process capable of utilizing high sulfur and/or low-grade fuels, may be a viable alternative to conventional coal combustion to meet future energy needs. Studies of an experimental 18-inch atmospheric fluidized bed combustor (FBC) are aimed at determining potential health risks and environmental acceptability of FBC effluents as compared to effluents from the conventional combustion of coal. Salmonella (Ames) mutagenicity bioassays provide a convenient method for detecting potential mutagens in the process stream, at different locations in the cleanup system, and for evaluating changes in mutagenicity associated with the use of different fuel types and operating conditions. Samples evaluated for mutagenicity include: methylene-chloride extracts of fly ash collected in bag filters and on high volume filters; methylene-chloride extracts of size-selected (respirable) fly ash collected by cascade impactors in the stack breech, and gaseous hydrocarbons collected on Tenax® adsorbent and Soxhlet extracted with n-pentane. Dose-dependent mutagenicity in at least three tester strains was detected in six of the nine bag-filter, fly-ash extracts; the addition of a metabolic activating system (rat liver S9) either increased, decreased or did not change the direct mutagenicity observed, depending upon the tester strain and extract used. Mutagenicity of respirable fly ash (< 10 μm) increased as the particle size decreased. No mutagenicity was detected in vapor phase hydrocarbons collected from four different positions in the process stream. Mutagenicity was detected in five of seven bag-filter ash samples obtained from the combustion of Montana Rosebud subbituminous coal. Combustion temperature and other operating conditions which may influence mutagenicity of the fly ash are discussed.     

Characteristics of DNA during binding of polycyclic aromatic hydrocarbonsin vitro

With the aid of various activation systems, polycyclic aromatic hydrocarbons (PAH) were bound covalently with DNA. The following activation systems were used: with the microsomal fraction of rat liver, with I₂, and with ascorbic acid and FeSO₄. In all three systems the appearance of breaks due to the action of the activating systems was observed in the DNA. The plateau on the curve representing PAH binding in the system with microsomal fraction is explained not by a decrease in the rate of metabolism of the hydrocarbons to zero and not by the presence of a limited number of specific combining sites for PAH in DNA, but by equality between the velocities of two opposite processes; binding of the metabolites and their removal through degradation of DNA. Against the background of breaks in DNA produced by the activation systems it was impossible to find changes introduced into the sedimentation characteristics of DNA by covalently bound PAH.Department for the Study of Carcinogenic Agents, Laboratory of Biochemistry of Tumors, Oncologic Scientific Center, Academy of Medical Sciences of the USSR, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR L. M. Shabad.) Translated from Byulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 87, No. 1, pp. 19–21, January, 1979.     

Mutagenic activity of the 4,5- and 9,10-dihydrodiols of benzo[J]fluoranthene and their syn- and anti-dihydrodiol epoxides in salmonella typhimurium

The objective of this study was to determine the relative mutagenic activities of the major dihydrodiol metabolites of benzo[j]fluoranthene (B[j]F) and their corresponding syn- and anti-dihydrodiol epoxides. Salmonella typhimurium tester strains TA97a, TA98, and TA100 were used to evaluate the mutagenic potencies of the parent hydrocarbon and these suspect proximate and ultimate mutagenic metabolites. B[j]F and the trans-dihydrodiol metabolites were active only in the presence of an external metabolic activation system (S9) with the exception of the B[j]F-4,5-diol, which was weakly active in TA98 and TA100 in the absence of S9. The B[j]F-4,5-diol was more mutagenic than the B[j]F-9,10-diol in tester strains TA98 and TA100, whereas the opposite effect was observed in TA97a. In the absence of S9, the anti-B[j]F-4,5-diol epoxide was more mutagenic than the syn-B[j]F-4,5-diol epoxide and the syn- and anti-B[j]F-9,10-diol epoxides in tester strains TA97a and TA100. The exceptional mutagenic potency of the anti-B[j]F-4,5-diol epoxide in TA100 resembles that observed by epoxides located within a fjord, or by the anti-diol epoxides of bay region methylated polycyclic aromatic hydrocarbons. In contrast, the mutagenicity of the pseudo bay region dihydrodiol epoxides arising from the B[j]F-9,10-diol more closely resembles that observed with the classical bay region dihydrodiol epoxides of chrysene. In summary, both dihydrodiol metabolites of B[j]F are mutagenic in S. typhimurium, and the relative potency varies among the tester strains. The highest mutagenic response was achieved in tester strain TA100, which detects base-pair substitutions. The most potent direct-acting dihydrodiol epoxide in this tester strain was the anti-B[j]F-4,5-diol epoxide, which agrees with the results of mouse skin painting studies that indicate that the B[j]F-4,5-diol is more tumorigenic that the parent hydrocarbon or the B[j]F-9,10-diol. A cova-lent DNA adduct formed between the anti-B[j]F-4,5-diol epoxide and deoxyguanosine was the major species of DNA adduct formed in S. typhimurium. This adduct corresponds to the major DNA adduct formed in mouse skin following application B[j]F.     

Enzyme-assisted bioremediation approach for synthetic dyes and polycyclic aromatic hydrocarbons degradation

Environmental protection from emerging pollutants has become a significant challenge for mankind as an increasing number of contaminants, including synthetic dyes and polycyclic aromatic hydrocarbons (PAHs), represent a serious risk to ecological and environmental balance. Most synthetic dyes have complex aromatic structures and are resistant to degrade by classical approaches, such as physical and chemical processes, including adsorption, chemical coagulation, flocculation, ion exchange, membrane separation, froth flotation, and reverse osmosis. Enzymes-assisted catalytic transformation of pollutants has become a potential alternative to classical methods because of their ability to react with complex compounds, a quick degradation rate, and producing less harmful by-products. Plant peroxidases, and microbial laccase and lignin-degrading peroxidases (manganese and lignin peroxidase) have gained significant attention for treating aromatic waste due to their capability of oxidizing and detoxifying a wide range of recalcitrant xenobiotics, including PAHs and synthetic dyes. Peroxidases being efficient biocatalysts detoxify an array of toxic compounds by simple free-radical mechanism resulting in the formation of oxidized and depolymerized products of significantly reduced toxicity. Moreover, it is an ecofriendly and economically favorable approach towards the biodegradation of recalcitrant and toxic industrial waste. Among microbial and plant peroxidases, bacterial enzymes have broad substrate specificity and can transform a wide range of recalcitrant substrates. Ligninolytic enzymes oxidize the aromatic ring into quinones and acids by producing free hydroxyl radicals instead of dihydrodiols and mineralize aromatic hydrocarbon in combination with cytochrome P450, monooxygenases, and epoxide hydrolases. In the review, an attempt has been made to provide detailed knowledge about the availability of inexpensive peroxidases sources, their mechanism of action, and degradation potential. The present review summarizes the exploitation of peroxidases from plants, bacteria, and fungus (manganese peroxidase, lignin peroxidase, and laccases) for detoxification and degradation of textile dyes as well as PAHs. Conclusively, peroxidases have great potential to react with almost all classes of synthetic dyes and most PAHs due to broad substrate specificity and transformed them into less harmful metabolites.     

Comparison of mutagenicity and calf thymus DNA adducts formed by the particulate and semivolatile fractions of vehicle exhausts

In this study we compared the ability of extractable organic material from particulate and semivolatile fractions of gasoline emission to induce mutations in bacteria and form adducts with calf thymus (CT) DNA with corresponding data obtained from diesel exhaust. Exhaust particles from gasoline-powered passenger cars were collected on filters and semivolatile compounds were collected on polyurethane foam (PUF). The mutagenicity of the soluble organic fraction (SOF) was determined in Salmonella typhimurium strain TA98 and the DNA binding of aromatic compounds in the extracts was assessed by in vitro incubations with CT DNA and rat liver S9 (oxidative activation) or xanthine oxidase (reductive activation) followed by butanol-enhanced (32)P-postlabeling analysis. Semivolatile fractions of gasoline emission collected on PUF formed more CT DNA adducts than filter extracts under all reaction conditions, but showed a lower mutagenic potential than the corresponding particulate samples. This suggests that the capacity of PUF to collect exhaust particle-derived compounds and/or the efficiency of xanthine oxidase and enzymes in the rat liver S9 to activate these compounds to DNA binding metabolites was higher than expected. Gasoline extracts, benzo[a]pyrene and diesel particulate matter (SRM 1650) formed more S9-mediated DNA adducts as their dose increased, although a linear dose-response was not observed for the gasoline exhausts. Lower concentrations of gasoline and diesel extracts bound to DNA with greater efficiency than did 8-fold higher doses, suggesting complex interactions and/or an inhibition of S9 enzyme activities by the high doses. Diesel extracts formed higher levels of adducts than gasoline extracts, especially with the reductive activation system, suggesting that diesel extracts contain high levels of nitro-polycyclic aromatic hydrocarbons (nitro-PAHs). The higher direct-acting Salmonella mutagenicity in diesel extracts in comparison with gasoline extracts is consistent with diesel extracts containing higher concentrations of nitro-PAHs. The results of this study indicate that diesel extracts are more mutagenic and form more DNA adducts than gasoline extracts and that the effects of extract dose on DNA adduct formation are complex.     

Molecular and functional analysis of naphthalene-degrading bacteria isolated from the effluents of indigenous tanneries

During present study, four naphthalene- metabolizing bacteria were isolated from tanneries effluents through enrichment on naphthalene as sole carbon source in minimal salt medium. The bacteria were analyzed to document growth pattern, naphthalene removal efficiency, biochemical and molecular characteristics, antibiotic sensitivity, and metabolic profile. The 16S ribosomal RNA gene sequences were compared through BLAST (basic local alignment search tool) similarity search tool and three isolates were found homologous to Brevibacillus agri strain NBRC 15538 and one similar to Burkholderia lata strain 383. The naphthalene removal efficiencies ranged from 1.16 ± 0.056 mg/h (IUBN1) to 1.379 ± 0.021 mg/h (IUBN26). All isolates were positive for p-nitrophenyl phosphate (PO₄), esculin, and inulin fermentation tests. Majority were positive for glucosaminidase (IUBN3, 17, and 26) and a few for mannitol and sorbitol fermentation (IUBN1). Identification of metabolites through gas chromatography–mass spectrometry and liquid chromatography–mass spectrometry analysis allowed tracing pathways associated with naphthalene degradation. Intermediates such as cis-dihydrodiolnaphthalene, 2-hydroxychromene-2-carboxylate, 6-hydroxyhexanoic acid, acetyl-CoA confirmed that the present study bacteria can metabolize naphthalene through a pathway which differs from the pathways reported in earlier known bacteria. Due to fast growth rates, high naphthalene removal potentials, and multiple degradation pathways, these bacteria can be exploited for bioremediation of naphthalene.     

Genotoxicity and physicochemical characteristics of traffic-related ambient particulate matter

Exposure to ambient particulate matter (PM) has been linked to several adverse health effects. Since vehicular traffic is a PM source of growing importance, we sampled total suspended particulate (TSP), PM(10), and PM(2.5) at six urban locations with pronounced differences in traffic intensity. The mutagenicity, DNA-adduct formation, and induction of oxidative DNA damage by the samples were studied as genotoxicological parameters, in relation to polycyclic aromatic hydrocarbon (PAH) levels, elemental composition, and radical-generating capacity (RGC) as chemical characteristics. We found pronounced differences in the genotoxicity and chemical characteristics of PM from the various locations, although we could not establish a correlation between traffic intensity and any of these characteristics for any of the PM size fractions. Therefore, the differences between locations may be due to local sources of PM, other than traffic. The concentration of total (carcinogenic) PAHs correlated positively with RGC, direct and S9-mediated mutagenicity, as well as the induction of DNA adducts and oxidative DNA damage. The interaction between total PAHs and transition metals correlated positively with DNA-adduct formation, particularly from the PM(2.5) fraction. RGC was not associated with one specific PM size fraction, but mutagenicity and DNA reactivity after metabolic activation were relatively high in PM(10) and PM(2.5), when compared with TSP. We conclude that the toxicological characteristics of urban PM samples show pronounced differences, even when PM concentrations at the sample sites are comparable. This implies that emission reduction strategies that take chemical and toxicological characteristics of PM into account may be useful for reducing the health risks associated with PM exposure.     

The use of adult rat liver cultures in the detection of the genotoxicity of various polycyclic aromatic hydrocarbons

The hepatocyte primary culture (HPC)-DNA repair test and the adult rat liver epithelial cell (ARL)—hypoxanthine-guanine phosphoribosyl transferase (HGPRT) mutagenesis assay are two in vitro short-term tests that possess intrinsic capability for xenobiotic biotransformation. Both assays detected the genotoxicity of a variety of carcinogenic polycyclic aromatic hydrocarbons. Thus, these two tests, which embody intact cellular metabolism, are useful for the evaluation of this class of carcinogens and provide results that strengthen those obtained in tests dependent upon subcellular metabolism.     

Induction of micronuclei and sister chromatid exchanges by polycyclic and N-heterocyclic aromatic hydrocarbons in cultured human lymphocytes

Many natural environments are contaminated with carcinogenic polycyclic aromatic hydrocarbons (PAHs) and N-heterocyclic aromatic hydrocarbons (NHAs) as complex mixtures of coal tar, petroleum, and shale oil. These potentially hazardous substances are prevalent at many former tar production and coal gasification sites. Three polycyclic [benzo-(a)pyrene (BaP), benz(a)anthracene (BAA), and 7, 12-dimethylbenz(a)anthracene (DMBA)] and two N-heterocyclic [7H-dibenzo(c, g)carbazole (DBC), and dibenz(a, j)acridine (DBA)] aromatic hydrocarbons were analyzed for cytotoxic and genotoxic effects on human lymphocytes. All of these polyaromatic compounds are normally present in the environment, except for DMBA. Lymphocytes from healthy donors were isolated from whole blood. The 5-ring polycyclic aromatic BaP consistently induced micronuclei in a linear dose-dependent manner with doses from 0.1–10.0 ug/ml, whereas the 4-ring compounds (BAA and DMBA) had no effect on the induction of micronuclei above controls except at 5 and 10 ug/ml. Of the two N-heterocyclic compounds, DBC produced a significant increase in micronuclei in lymphocytes, but the dose response tended to plateau above 0.1 ug/ml. DBA showed an effect on the frequency of micronuclei above controls only at high doses of 5 and 10 ug/ml. The average background frequency of micronuclei for 7 lymphocyte donors averaged 3.1 per 1, 000 stimulated cells, whereas the average frequency of micronuclei at 10 ug/ml BaP was 36.8 per 1,000 stimulated cells. The lowest effective dose in 2 donors for BaP occurred at 0.1 ug/ml. At a challenge dose of 1 ug/ml (4 uM) of BaP, considerable variation in micronuclei induction between 7 individuals was observed, ranging from 2–6-fold increases above spontaneous frequency. Over a dose range of 1–10.0 ug/ml (4–40 uM), BaP also induced sister chromatid exchanges (SCEs) in lymphocytes, whereas BAA had no effect above controls. Parallel studies of both cytogenetic endpoints showed that the micronucleus assay is a more sensitive indicator of BaP exposure at equivalent doses. Mitotic and replication indices of BaP-exposed lymphocytes showed that cell proliferation is only moderately inhibited even at the highest dose; this shows that bulky DNA-adducts are generally compatible with cell survival. The cytogenetic data are consistent, firstoff, with reports that individuals in the population vary widely with respect to the inducibility of the CYP1A1 gene, which is known to be involved in polycyclic aromatic hydrocarbon metabolism, in particular, in BaP. Secondly, the data support the fact that polyaromatic compounds differ with regard to micronucleus induction within the same sample(s) of human lymphocytes, indicating selective metabolism of polyaromatic compounds that may reflect carcinogen sensitivity of the individual. Thirdly, it would appear that the micronucleus induction in human lymphocytes by PAHs is an overall-sensitive endpoint for measuring PAH exposure. Lastly, this is the first report of the use of the micronucleus assay to assess a series of PAHs and NHAs for their ability to induce genetic damage in human lymphocytes. © 1995 Wiley-Liss, Inc.     

Chemico/biological investigation of contaminated sediment from the hamilton harbour area of Western Lake Ontario

Highly contaminated sediment from the Hamilton Harbour area of western Lake Ontario was examined using a bioassay-directed fractionation methodology. A sediment sample was extracted using a Soxhlet apparatus and the resulting extract was fractionated into compound classes using an alumina clean-up step and high performance liquid chromatographic techniques. The resulting fractions were subjected to bioassays using TA98- and TA100-like strains modified by the inclusion of genes for the activating enzymes nitroreductase and O-acetyl-transferase. The majority of the mutagenic activity displayed by the sample extract was found to be present in the fraction containing the polycyclic aromatic hydrocarbons (PAH). Extracts of the PAH-containing fraction displayed dramatically higher responses with the TA100 type strains with metabolic activation. Further separation of the PAH-containing fraction showed the majority of the biological activity coeluted with PAH having molecular masses of 276, 278, and 302 amu. © 1993 Wiley-Liss, Inc.     

Radiosterilization of rat liver microsome containing postmitochondrial supernatant for mutation assays

Gamma-irradiation was effectively employed to sterilize rat liver postmito-chondrial supernant (PMS), which is required for the metabolic activation of soots and soot-derived polycyclic aromatic hydrocarbons to mutagens. When a known number of Bacillus subtilis spores were added to the PMS and gammairradiated at ?80° C, a 2-Mrad dose resulted in a 7.5 log kill of the spores. A dose of 3 Mrads was selected as a sufficient effective sterilizing dose and had no significant effect upon the ability of gamma-irradiated PMS to metabolically activate diesel soot and two diesel soot components, benzo(a)pyrene and fluoranthene to mutagens in a Salmonella typhimurium 8-azaguanine resistance forward mutation assay. Three Mrads of gamma-irradiation also had no effect upon the ability of PMS to activate benzo[a]pyrene to a mutagen for the human lymphoblasts. However, gamma-irradiation did reduce the ability of PMS to activate dimethylnitrosamine to a mutagen for S typhimurium.     

Meat-related mutagens/carcinogens in the etiology of colorectal cancer

Diets containing substantial amounts of red or preserved meats may increase the risk of various cancers, including colorectal cancer. This association may be due to a combination of factors such as the content of fat, protein, iron, and/or meat preparation (e.g., cooking or preserving methods). Red meat may be associated with colorectal cancer by contributing to N-nitroso compound (NOC) exposure. Humans can be exposed to NOCs by exogenous routes (from processed meats in particular) and by endogenous routes. Endogenous exposure to NOCs is dose-dependently related to the amount of red meat in the diet. Laboratory results have shown that meats cooked at high temperatures contain other potential mutagens in the form of heterocyclic amines (HCAs) and polycyclic aromatic hydrocarbons (PAHs). To investigate the role of these compounds, we have created separate databases for HCAs and PAHs, which we have used in conjunction with a validated meat-cooking food frequency questionnaire. The role of meat type, cooking methods, doneness levels, and meat-cooking mutagens has been examined in both case-control studies and prospective cohort studies, with mixed results. Here, we review the current epidemiologic knowledge of meat-related mutagens, and evaluate the types of studies that may be required in the future to clarify the association between meat consumption and colorectal cancer.     

Precision Synthesis of Boron-Doped Graphene Nanoribbons: Recent Progress and Perspectives

Structurally precision graphene nanoribbons (GNRs) have attracted great interest considering their prospective applications as organic carbon materials for nanoelectronics. The electronic properties of GNRs not only critically depend on the edge structure and width but also on the heteroatom type, doping position, and concentration. Motivated by the recent undisputable progress in the synthesis of stable boron-doped polycyclic aromatic hydrocarbons (B-PAHs), considerable efforts have been devoted to the precision synthesis of the corresponding boron-doped GNRs (B-GNRs) via bottom-up synthesis approach in recent years in view of the extraordinary ability of boron doping on modulating their physiochemical properties. In this review, an overview of the bottom-up organic synthesis of B-GNRs, including the precursor design and synthesis, structure characterization of the resulting B-GNRs, and investigation of their electronic properties is provided. Moreover, the future challenges and perspectives regarding the bottom-up synthesis of B-GNRs are also discussed. The authors hope that this review will further stimulate the synthesis and device integrations of B-GNRs with a combined effort from different disciplines.     

Sources of polycyclic aromatic hydrocarbon exposure in non-occupationally exposed Koreans

Urinary 1-hydroxypyrene (1-OHP), an exposure biomarker for polycyclic aromatic hydrocarbons (PAHs), was used to identify potential sources of PAH exposure for 660 Koreans who were not occupationally exposed to PAHs (65% male; 35% female; mean age, 36.5 +/- 11.1 years). In this study, 74% of subjects had detectable levels of urinary 1-OHP, with a concentration range of 0.001-3.796 microg/L (median, 0.079 microg/L). A backward elimination was conducted: five variables were selected with a significance level for removal of P < or = 0.1. The results of this study showed that residence in areas with relatively poor environmental conditions (Seoul and Suwon) was strongly associated with high concentrations of urinary 1-OHP (P = 0.007), while consumption of fried chicken and length of time spent outdoors had marginal positive associations with urinary 1-OHP levels (P = 0.06 and P = 0.09, respectively). Compared with the above three factors, tobacco smoking and urinary cotinine levels were poorly associated with urinary 1-OHP (P = 0.16 and 0.23, respectively). Pear consumption had an inverse association with urinary 1-OHP levels (P < 0.01). Individual variations in urinary 1-OHP concentrations were evaluated by considering the subjects' age, sex, and genetic polymorphisms in enzymes involved in the metabolism of PAHs. Among the individual variations, GSTT1-present subjects showed higher 1-OHP levels than GSTT1-absent subjects in cities having 10-microm particulate matter (PM(10)) levels and population density lower than those of Seoul and Suwon (P < 0.05). These epidemiological results suggest that the above factors that should be considered in preventing PAH exposure.     

Correlation between meteorological conditions and mutagenicity of airborne particupate samples in a tropical monsoon climate area from Kaohsiung City,Taiwan

Kaohsiung is a city of 1.5 million located in the southern part of Taiwan. It has a serious air pollution problem mainly attributable to much industrial and commercial activity. In order to estimate the effects of traffic, season, and meteorological conditions on the mutagenicity of Kaohsiung City's urban ambient particulate matter, 624 airborne particulate samples were collected on a weekly basis from 12 locations for an entire year. The mutagenic potential of acetone extracts of air samples was evaluated by the Salmonella/microsomal test with S. typhimurium TA98 in the presence and absence of S9 mixtures. The air samples from November 1990 showed the highest direct and indirect mutagenicity among the 12 months, whereas those from June and July 1991 had the lowest direct and indirect mutagenic activity, respectively. The mutagenicity showed a good correlation with amounts of the acetone extractable matter of airborne particulates. The meteorological conditions, monthly mean precipitation, and wind speed also showed a good correspondence with mutagenicity. Wind direction and temperature had a moderate relationship. The major mutagenic fractions of air samples that had the highest mutagenic activity in a month were purified using Sephadex LH-20 column chromatography, and the contents of PAHs, 1-NP, and DNPs were analyzed by HPLC. The characteristic concentration ratios of PAHs indicated that, for the main pollution sources of airborne particulates from Kaohsiung city, the mobile sources were more important than the stationary ones. The total amounts of 1-NP and DNPs in airborne particulates seemed to correspond to their mutagenicity. Although the total amounts of 1-NP and DNPs in the air samples correlated with their mutagenicity, the major mutagenic chemicals in the airborne particulate samples from Kaohsiung City need further investigation. © 1994 Wiley-Liss, Inc.     

Impact of p53 function on the sulfotransferase-mediated bioactivation of the alkylated polycyclic aromatic hydrocarbon 1-hydroxymethylpyrene in vitro

The tumor suppressor p53, encoded by TP53, is known as the “guardian of the genome.” Sulfotransferases (SULTs) are involved in the metabolism of alkylated polycyclic aromatic hydrocarbons such as 1-hydroxymethylpyrene (1-HMP), which is a known substrate for SULT1A1. To investigate the impact of TP53 on the metabolic activation of 1-HMP, a panel of isogenic human colorectal HCT116 cells having TP53(+/+), TP53(+/−), or TP53(−/−) were treated with 10 μM 1-HMP for 24 hr. 1-HMP-DNA adduct formation was determined by ultraperformance liquid chromatography-tandem mass spectrometry analysis, which quantified two nucleoside adducts N²-(1-methylpyrenyl)-2′-deoxyguanosine and N⁶-(1-methylpyrenyl)-2′-deoxyadenosine. 1-HMP treatment resulted in significantly (~40-fold) higher DNA adduct levels in TP53(+/+) cells than in the other cell lines. Higher levels of 1-HMP-induced DNA adducts in TP53(+/+) cells correlated with higher basal expression of SULT1A1/3 in this cell line, but 1-HMP treatment showed no effect on the expression of this protein. These results indicate that the cellular TP53 status is linked to the SULT1A1/3-mediated bioactivation of 1-HMP, thereby broadening the spectrum of p53's targets. Environ. Mol. Mutagen., 60:752–758, 2019. © 2019 Wiley Periodicals, Inc.