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Cross KP, DeMarini DM. Analysis of chemical structures and mutations detected by Salmonella TA98 and TA100. Mutat Res 2023; 827:111838. [PMID: 37804576 PMCID: PMC10841823 DOI: 10.1016/j.mrfmmm.2023.111838] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2023] [Revised: 09/09/2023] [Accepted: 09/21/2023] [Indexed: 10/09/2023]
Abstract
As part of an analysis performed under the auspices of the International Workshop on Genotoxicity Testing (IWGT) in 2017, we and others showed that Salmonella frameshift strain TA98 and base-substitution strain TA100 together + /- S9 detected 93% of the mutagens detected by all the bacterial strains recommended by OECD TG471 (Williams et al., Mutation Res. 848:503081, 2019). We have extended this analysis by identifying the numbers and chemical classes of chemicals detected by these two strains either alone or in combination, including the role of S9. Using the Leadscope 2021 SAR Genetox database containing > 21,900 compounds, our dataset containing 7170 compounds tested in both TA98 and TA100. Together, TA98 and TA100 detected 94% (3733/3981) of the mutagens detected using all the TG471-recommended bacterial strains; 39% were mutagenic in one or both strains. TA100 detected 77% of all of these mutagens and TA98 70%. Considering the overlap of detection by both strains, 12% of these mutagens were detected only by TA98 and 19% only by TA100. In the absence of S9, sensitivity dropped by 31% for TA98 and 29% for TA100. Overall, 32% of the mutagens required S9 for detection by either strain; 9% were detected only without S9. Using the 2021 Leadscope Genetox Expert Alerts, TA100 detected 18 mutagenic alerting chemical classes with better sensitivity than TA98, whereas TA98 detected 10 classes better than TA100. TA100 detected more chemical classes than did TA98, especially hydrazines, azides, various di- and tri-halides, various nitrosamines, epoxides, aziridines, difurans, and half-mustards; TA98 especially detected polycyclic primary amines, various aromatic amines, polycyclic aromatic hydrocarbons, triazines, and dibenzo-furans. Model compounds with these structures induce primarily G to T mutations in TA100 and/or a hotspot GC deletion in TA98. Both TA98 and TA100 + /- S9 are needed for adequate mutagenicity screening with the Salmonella (Ames) assay.
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Affiliation(s)
| | - David M DeMarini
- Center for Environmental Measurement and Modeling, US Environmental Protection Agency, Research Triangle Park, NC 27711, USA
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Sun M, Zhou Y, Wang Y, Zheng X, Cui J, Zhang D, Zhang J, Zhang R. Seasonal discrepancies in peroxyacetyl nitrate (PAN) and its correlation with ozone and PM 2.5: Effects of regional transport from circumjacent industrial cities. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 785:147303. [PMID: 33933769 DOI: 10.1016/j.scitotenv.2021.147303] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Revised: 04/16/2021] [Accepted: 04/18/2021] [Indexed: 06/12/2023]
Abstract
Peroxyacetyl nitrate (PAN) is the most important reservoir of nitrogen oxides, with effects on atmospheric oxidation capacity and regional nitrogen distribution. The first yearlong observational study of PAN was conducted from September 2018 to August 2019 at a suburban site and an urban site in Zhengzhou, Henan Province, central China. Compared with studies over the past two decades, summer PAN pollution at the suburban site and winter PAN pollution at both sites were more significant, with annual average concentrations of 1.96 ± 1.44 and 2.01 ± 1.59 ppbv, respectively. Seasonal PAN discrepancies between the urban and suburban areas were analyzed in detail. Active PAN formation, regional transport, photochemical precursors, and PAN lifetime played key roles during seasons with elevated PAN (winter and spring). According to the results of cluster analysis and potential source contribution function analysis, during the cold months, short-distance air mass transport from the east, south, and southeast of Henan Province and southern Hebei Province increased PAN pollution in urban Zhengzhou. PAN source areas were located in circumjacent industrial cities surrounding Zhengzhou except in the northeastern direction. Based on the relationships between pollutant concentrations, wind speed, and wind direction, a strong positive correlation between PAN and PM2.5 (and O3) existed in winter due to their joint transport. A slow-moving, low-height air mass passed through surrounding industrial cities before reaching the study area, carrying both pollutants and leading to strong consistency between PAN and O3 levels. The long-term PAN characteristics described in this study will help clarify the causes of regional air pollution in inland city agglomerations. Moreover, the PAN correlations and joint transport of PAN and PM2.5 (or O3) support the use of PAN as an indicator of air pollution introduced from surrounding industrial areas.
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Affiliation(s)
- Mei Sun
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Ying Zhou
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China.
| | - Yifei Wang
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Xiaochen Zheng
- Institute of Environmental Engineering (IfU), ETH Zürich, 8093 Zürich, Switzerland
| | - Jia'nan Cui
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Dong Zhang
- Research Institute of Environmental Science, College of Chemistry and Molecular Engineering, Zhengzhou University, Zhengzhou 450001, China
| | - Jianbo Zhang
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China.
| | - Ruiqin Zhang
- Research Institute of Environmental Science, College of Chemistry and Molecular Engineering, Zhengzhou University, Zhengzhou 450001, China
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Riedel TP, DeMarini DM, Zavala J, Warren SH, Corse EW, Offenberg JH, Kleindienst TE, Lewandowski M. Mutagenic atmospheres resulting from the photooxidation of aromatic hydrocarbon and NO x mixtures. ATMOSPHERIC ENVIRONMENT (OXFORD, ENGLAND : 1994) 2018; 178:164-172. [PMID: 29725240 PMCID: PMC5921836 DOI: 10.1016/j.atmosenv.2018.01.052] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Although many volatile organic compounds (VOCs) are regulated to limit air pollution and the consequent health effects, the photooxidation products generally are not. Thus, we examined the mutagenicity in Salmonella TA100 of photochemical atmospheres generated in a steady-state atmospheric simulation chamber by irradiating mixtures of single aromatic VOCs, NOx, and ammonium sulfate seed aerosol in air. The 10 VOCs examined were benzene; toluene; ethylbenzene; o-, m-, and p-xylene; 1,2,4- and 1,3,5-trimethylbenzene; m-cresol; and naphthalene. Salmonella were exposed at the air-agar interface to the generated atmospheres for 1, 2, 4, 8, or 16 h. Dark-control exposures produced non-mutagenic atmospheres, illustrating that the gas-phase precursor VOCs were not mutagenic at the concentrations tested. Under irradiation, all but m-cresol and naphthalene produced mutagenic atmospheres, with potencies ranging from 2.0 (p-xylene) to 10.4 (ethylbenzene) revertants m3 mgC-1 h-1. The mutagenicity was due exclusively to direct-acting late-generation products of the photooxidation reactions. Gas-phase chemical analysis showed that a number of oxidized organic chemical species enhanced during the irradiated exposure experiments correlated (r ≥ 0.81) with the mutagenic potencies of the atmospheres. Molecular formulas assigned to these species indicated that they likely contained peroxy acid, aldehyde, alcohol, and other functionalities.
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Affiliation(s)
- Theran P. Riedel
- National Exposure Research Laboratory, United States Environmental Protection Agency, Research Triangle Park, North Carolina, United States
- Corresponding Author, Mailing address: U.S. EPA, 109 T.W. Alexander Dr, D205-3, Research Triangle Park, NC, USA 27711, , Phone: +1 919-541-0877, Fax: +1 919-541-0239
| | - David M. DeMarini
- National Health and Environmental Effects Research Laboratory, United States Environmental Protection Agency, Research Triangle Park, North Carolina, United States
| | - Jose Zavala
- Oak Ridge Institute for Science and Education, National Health and Environmental Effects Research Laboratory, United States Environmental Protection Agency, Research Triangle Park, North Carolina, United States
| | - Sarah H. Warren
- National Health and Environmental Effects Research Laboratory, United States Environmental Protection Agency, Research Triangle Park, North Carolina, United States
| | - Eric W. Corse
- Jacobs Technology, Cary, North Carolina, United States
| | - John H. Offenberg
- National Exposure Research Laboratory, United States Environmental Protection Agency, Research Triangle Park, North Carolina, United States
| | - Tadeusz E. Kleindienst
- National Exposure Research Laboratory, United States Environmental Protection Agency, Research Triangle Park, North Carolina, United States
| | - Michael Lewandowski
- National Exposure Research Laboratory, United States Environmental Protection Agency, Research Triangle Park, North Carolina, United States
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Zavala J, Krug JD, Warren SH, Krantz QT, King C, McKee J, Gavett SH, Lewandowski M, Lonneman WA, Kleindienst TE, Meier MJ, Higuchi M, Gilmour MI, DeMarini DM. Evaluation of an Air Quality Health Index for Predicting the Mutagenicity of Simulated Atmospheres. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2018; 52:3045-3053. [PMID: 29406743 PMCID: PMC5858694 DOI: 10.1021/acs.est.8b00613] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
No study has evaluated the mutagenicity of atmospheres with a calculated air quality health index (AQHI). Thus, we generated in a UV-light-containing reaction chamber two simulated atmospheres (SAs) with similar AQHIs but different proportions of criteria pollutants and evaluated them for mutagenicity in three Salmonella strains at the air-agar interface. We continuously injected into the chamber gasoline, nitric oxide, and ammonium sulfate, as well as either α-pinene to produce SA-PM, which had a high concentration of particulate matter (PM): 119 ppb ozone (O3), 321 ppb NO2, and 1007 μg/m3 PM2.5; or isoprene to produce SA-O3, which had a high ozone (O3) concentration: 415 ppb O3, 633 ppb NO2, and 55 μg/m3 PM2.5. Neither PM2.5 extracts, NO2, or O3 alone, nor nonphoto-oxidized mixtures were mutagenic or cytotoxic. Both photo-oxidized atmospheres were largely direct-acting base-substitution mutagens with similar mutagenic potencies in TA100 and TA104. The mutagenic potencies [(revertants/h)/(mgC/m3)] of SA-PM (4.3 ± 0.4) and SA-O3 (9.5 ± 1.3) in TA100 were significantly different ( P < 0.0001), but the mutation spectra were not ( P = 0.16), being ∼54% C → T and ∼46% C → A. Thus, the AQHI may have some predictive value for the mutagenicity of the gas phase of air.
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Affiliation(s)
- Jose Zavala
- ORISE Research Fellow, National Health and Environmental Effects Research Laboratory, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711, United States
| | - Jonathan D. Krug
- National Environmental Research Laboratory, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711, United States
| | - Sarah H. Warren
- National Health and Environmental Effects Research Laboratory, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711, United States
| | - Q. Todd Krantz
- National Health and Environmental Effects Research Laboratory, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711, United States
| | - Charly King
- National Health and Environmental Effects Research Laboratory, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711, United States
| | - John McKee
- National Health and Environmental Effects Research Laboratory, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711, United States
| | - Stephen H. Gavett
- National Health and Environmental Effects Research Laboratory, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711, United States
| | - Michael Lewandowski
- National Environmental Research Laboratory, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711, United States
| | - William A. Lonneman
- National Environmental Research Laboratory, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711, United States
| | - Tadeusz E. Kleindienst
- National Environmental Research Laboratory, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711, United States
| | - Matthew J. Meier
- Biology Department, Carleton University, Ottawa, Ontario K1S 5B6, Canada
| | - Mark Higuchi
- National Health and Environmental Effects Research Laboratory, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711, United States
| | - M. Ian Gilmour
- National Health and Environmental Effects Research Laboratory, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711, United States
| | - David M. DeMarini
- National Health and Environmental Effects Research Laboratory, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711, United States
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5
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Krug JD, Lewandowski M, Offenberg JH, Turlington JM, Lonneman WA, Modak N, Krantz QT, King C, Gavett SH, Gilmour MI, DeMarini DM, Kleindienst TE. Photochemical Conversion of Surrogate Emissions for Use in Toxicological Studies: Role of Particulate- and Gas-Phase Products. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2018; 52:3037-3044. [PMID: 29381868 PMCID: PMC6145069 DOI: 10.1021/acs.est.7b04879] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
The production of photochemical atmospheres under controlled conditions in an irradiation chamber permits the manipulation of parameters that influence the resulting air-pollutant chemistry and potential biological effects. To date, no studies have examined how contrasting atmospheres with a similar Air Quality Health Index (AQHI), but with differing ratios of criteria air pollutants, might differentially affect health end points. Here, we produced two atmospheres with similar AQHIs based on the final concentrations of ozone, nitrogen dioxide, and particulate matter (PM2.5). One simulated atmosphere (SA-PM) generated from irradiation of ∼23 ppmC gasoline, 5 ppmC α-pinene, 529 ppb NO, and 3 μg m-3 (NH4)2SO4 as a seed resulted in an average of 976 μg m-3 PM2.5, 326 ppb NO2, and 141 ppb O3 (AQHI 97.7). The other atmosphere (SA-O3) generated from 8 ppmC gasoline, 5 ppmC isoprene, 874 ppb NO, and 2 μg m-3 (NH4)2SO4 resulted in an average of 55 μg m-3 PM2.5, 643 ppb NO2, and 430 ppb O3 (AQHI of 99.8). Chemical speciation by gas chromatography showed that photo-oxidation degraded the organic precursors and promoted the de novo formation of secondary reaction products such as formaldehyde and acrolein. Further work in accompanying papers describe toxicological outcomes from the two distinct photochemical atmospheres.
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Affiliation(s)
- Jonathan D. Krug
- National Exposure Research Laboratory, United States Environmental Protection Agency, Research Triangle Park, North Carolina 27711, United States
| | - Michael Lewandowski
- National Exposure Research Laboratory, United States Environmental Protection Agency, Research Triangle Park, North Carolina 27711, United States
| | - John H. Offenberg
- National Exposure Research Laboratory, United States Environmental Protection Agency, Research Triangle Park, North Carolina 27711, United States
| | - John M. Turlington
- National Exposure Research Laboratory, United States Environmental Protection Agency, Research Triangle Park, North Carolina 27711, United States
| | - William A. Lonneman
- Senior Environmental Employment (SEE) Program/NCBA, Washington, D.C. 20005, United States
| | - Nabanita Modak
- National Health and Environmental Effects Research Laboratory, United States Environmental Protection Agency, Research Triangle Park, North Carolina 27711, United States
| | - Q. Todd Krantz
- National Health and Environmental Effects Research Laboratory, United States Environmental Protection Agency, Research Triangle Park, North Carolina 27711, United States
| | - Charly King
- National Health and Environmental Effects Research Laboratory, United States Environmental Protection Agency, Research Triangle Park, North Carolina 27711, United States
| | - Stephen H. Gavett
- National Health and Environmental Effects Research Laboratory, United States Environmental Protection Agency, Research Triangle Park, North Carolina 27711, United States
| | - M. Ian Gilmour
- National Health and Environmental Effects Research Laboratory, United States Environmental Protection Agency, Research Triangle Park, North Carolina 27711, United States
| | - David M. DeMarini
- National Health and Environmental Effects Research Laboratory, United States Environmental Protection Agency, Research Triangle Park, North Carolina 27711, United States
| | - Tadeusz E. Kleindienst
- National Exposure Research Laboratory, United States Environmental Protection Agency, Research Triangle Park, North Carolina 27711, United States
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Claxton LD. The history, genotoxicity, and carcinogenicity of carbon-based fuels and their emissions: Part 5. Summary, comparisons, and conclusions. MUTATION RESEARCH-REVIEWS IN MUTATION RESEARCH 2015; 763:103-47. [DOI: 10.1016/j.mrrev.2014.10.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2014] [Revised: 10/04/2014] [Accepted: 10/06/2014] [Indexed: 12/19/2022]
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7
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Claxton LD. The history, genotoxicity, and carcinogenicity of carbon-based fuels and their emissions. Part 3: Diesel and gasoline. MUTATION RESEARCH-REVIEWS IN MUTATION RESEARCH 2015; 763:30-85. [DOI: 10.1016/j.mrrev.2014.09.002] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2014] [Revised: 09/10/2014] [Accepted: 09/12/2014] [Indexed: 11/26/2022]
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Chen JM, Férec C, Cooper DN. Patterns and mutational signatures of tandem base substitutions causing human inherited disease. Hum Mutat 2013; 34:1119-30. [PMID: 23606422 DOI: 10.1002/humu.22341] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2013] [Accepted: 04/09/2013] [Indexed: 12/31/2022]
Abstract
Tandem base substitutions (TBSs) are multiple mutations that comprise two or more contiguous nucleotide substitutions without any net gain or loss of bases. They have recently become recognized as a distinct category of human genomic variant. However, their role in causing human inherited disease so far has not been studied methodically. Here, using data from the Human Gene Mutation Database (http://www.hgmd.org), we identified 477 events to be TBSs (doublets, 448; triplets, 16; and quadruplets to octuplets, 13). A comprehensive sequence pattern and context analysis implied the likely fundamental importance of translesion synthesis (TLS) DNA polymerases in generating these diverse TBSs but revealed that TLS polymerases may operate differently in generating TBSs of ≤ 3 bases (bypass of endogenous DNA lesions) than those of ≥ 4 bases (serial replication slippage). Moreover, GC was found to be the most frequently affected dinucleotide with GC/GC>AA/TT being the most frequent double TBS. Comparison with cancer genome mutational spectra allowed us to conclude that human germline TBSs arise predominantly through the action of endogenous mechanisms of mutagenesis rather than through exposure to exogenous mutagens. Finally, the rates of double and triple TBSs were estimated to be 0.2-1.2 × 10(-10) and 0.8-4.8 × 10(-12) per base per generation, respectively.
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Affiliation(s)
- Jian-Min Chen
- Institut National de la Santé et de la Recherche Médicale, Brest, France.
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Kirkland D, Reeve L, Gatehouse D, Vanparys P. A core in vitro genotoxicity battery comprising the Ames test plus the in vitro micronucleus test is sufficient to detect rodent carcinogens and in vivo genotoxins. Mutat Res 2011; 721:27-73. [PMID: 21238603 DOI: 10.1016/j.mrgentox.2010.12.015] [Citation(s) in RCA: 161] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2010] [Revised: 11/12/2010] [Accepted: 12/15/2010] [Indexed: 01/27/2023]
Abstract
In vitro genotoxicity testing needs to include tests in both bacterial and mammalian cells, and be able to detect gene mutations, chromosomal damage and aneuploidy. This may be achieved by a combination of the Ames test (detects gene mutations) and the in vitro micronucleus test (MNvit), since the latter detects both chromosomal aberrations and aneuploidy. In this paper we therefore present an analysis of an existing database of rodent carcinogens and a new database of in vivo genotoxins in terms of the in vitro genotoxicity tests needed to detect their in vivo activity. Published in vitro data from at least one test system (most were from the Ames test) were available for 557 carcinogens and 405 in vivo genotoxins. Because there are fewer publications on the MNvit than for other mammalian cell tests, and because the concordance between the MNvit and the in vitro chromosomal aberration (CAvit) test is so high for clastogenic activity, positive results in the CAvit test were taken as indicative of a positive result in the MNvit where there were no, or only inadequate data for the latter. Also, because Hprt and Tk loci both detect gene-mutation activity, a positive Hprt test was taken as indicative of a mouse-lymphoma Tk assay (MLA)-positive, where there were no data for the latter. Almost all of the 962 rodent carcinogens and in vivo genotoxins were detected by an in vitro battery comprising Ames+MNvit. An additional 11 carcinogens and six in vivo genotoxins would apparently be detected by the MLA, but many of these had not been tested in the MNvit or CAvit tests. Only four chemicals emerge as potentially being more readily detected in MLA than in Ames+MNvit--benzyl acetate, toluene, morphine and thiabendazole--and none of these are convincing cases to argue for the inclusion of the MLA in addition to Ames+MNvit. Thus, there is no convincing evidence that any genotoxic rodent carcinogens or in vivo genotoxins would remain undetected in an in vitro test battery consisting of Ames+MNvit.
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Affiliation(s)
- David Kirkland
- Kirkland Consulting, PO Box 79, Tadcaster LS24 0AS, United Kingdom.
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Scaringe WA, Li K, Gu D, Gonzalez KD, Chen Z, Hill KA, Sommer SS. Somatic microindels in human cancer: the insertions are highly error-prone and derive from nearby but not adjacent sense and antisense templates. Hum Mol Genet 2008; 17:2910-8. [PMID: 18632684 DOI: 10.1093/hmg/ddn190] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Somatic microindels (microdeletions with microinsertions) have been studied in normal mouse tissues using the Big Blue lacI transgenic mutation detection system. Here we analyze microindels in human cancers using an endogenous and transcribed gene, the TP53 gene. Microindel frequency, the enhancement of 1-2 microindels and other features are generally similar to that observed in the non-transcribed lacI gene in normal mouse tissues. The current larger sample of somatic microindels reveals recurroids: mutations in which deletions are identical and the co-localized insertion is similar. The data reveal that the inserted sequences derive from nearby but not adjacent sequences in contrast to the slippage that characterizes the great majority of pure microinsertions. The microindel inserted sequences derive from a template on the sense or antisense strand with similar frequency. The estimated error rate of the insertion process of 13% per bp is by far the largest reported in vivo, with the possible exception of somatic hypermutation in the immunoglobulin gene. The data constrain possible mechanisms of microindels and raise the question of whether microindels are 'scars' from the bypass of large DNA adducts by a translesional polymerase, e.g. the 'Tarzan model' presented herein.
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Affiliation(s)
- William A Scaringe
- Department of Molecular Genetics, City of Hope National Medical Center, 1500 E. Duarte Rd, Duarte, CA 91010, USA
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Sandercock LE, Hahn JN, Li L, Luchman H, Giesbrecht JL, Peterson LA, Jirik FR. Mgmt deficiency alters the in vivo mutational spectrum of tissues exposed to the tobacco carcinogen 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK). Carcinogenesis 2008; 29:866-74. [DOI: 10.1093/carcin/bgn030] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
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Lambert IB, Singer TM, Boucher SE, Douglas GR. Detailed review of transgenic rodent mutation assays. Mutat Res 2005; 590:1-280. [PMID: 16081315 DOI: 10.1016/j.mrrev.2005.04.002] [Citation(s) in RCA: 247] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2005] [Revised: 04/04/2005] [Accepted: 04/12/2005] [Indexed: 11/17/2022]
Abstract
Induced chromosomal and gene mutations play a role in carcinogenesis and may be involved in the production of birth defects and other disease conditions. While it is widely accepted that in vivo mutation assays are more relevant to the human condition than are in vitro assays, our ability to evaluate mutagenesis in vivo in a broad range of tissues has historically been quite limited. The development of transgenic rodent (TGR) mutation models has given us the ability to detect, quantify, and sequence mutations in a range of somatic and germ cells. This document provides a comprehensive review of the TGR mutation assay literature and assesses the potential use of these assays in a regulatory context. The information is arranged as follows. (1) TGR mutagenicity models and their use for the analysis of gene and chromosomal mutation are fully described. (2) The principles underlying current OECD tests for the assessment of genotoxicity in vitro and in vivo, and also nontransgenic assays available for assessment of gene mutation, are described. (3) All available information pertaining to the conduct of TGR assays and important parameters of assay performance have been tabulated and analyzed. (4) The performance of TGR assays, both in isolation and as part of a battery of in vitro and in vivo short-term genotoxicity tests, in predicting carcinogenicity is described. (5) Recommendations are made regarding the experimental parameters for TGR assays, and the use of TGR assays in a regulatory context.
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Affiliation(s)
- Iain B Lambert
- Mutagenesis Section, Environmental Health Sciences Bureau, Healthy Environments and Consumer Safety Branch, 0803A, Health Canada, Ottawa, Ont., Canada K1A 0L2.
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Mei N, Heflich RH, Chou MW, Chen T. Mutations induced by the carcinogenic pyrrolizidine alkaloid riddelliine in the liver cII gene of transgenic big blue rats. Chem Res Toxicol 2005; 17:814-8. [PMID: 15206902 PMCID: PMC6375673 DOI: 10.1021/tx049955b] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Riddelliine is a naturally occurring pyrrolizidine alkaloid that forms a number of different mononucleotide and dinucleotide adducts in DNA. It is a rodent carcinogen and a potential human hazard via food contamination. To examine the mutagenicity of riddelliine, groups of six female transgenic Big Blue rats were gavaged with 0.1, 0.3, and 1.0 mg riddelliine per kg body weight. The middle and high doses resulted in liver tumors in a previous carcinogenesis bioassay. The animals were treated 5 days a week for 12 weeks and sacrificed 1 day after the last treatment. The liver DNA was isolated for analysis of the mutant frequency (MF) in the transgenic cII gene, and the types of mutations were characterized by sequencing the mutants. A significant dose-dependent increase in MF was found, increasing from 30 x 10(-)(6) in the control animals to 47, 55, and 103 x 10(-)(6) in the low, middle, and high dose groups, respectively. Molecular analysis of the mutants indicated that there was a statistically significant difference between the mutational spectra from the riddelliine-treated and the control rats. A G:C --> T:A transversion (35%) was the major type of mutation in rats treated with riddelliine, whereas a G:C --> A:T transition (55%) was the predominant mutation in the controls. In addition, mutations from the riddelliine-treated rats included an unusually high frequency (8%) of tandem base substitutions of GG --> TT and GG --> AT. These results indicate that riddelliine is a genotoxic carcinogen in rat liver and that the types of mutations induced by riddelliine are consistent with riddelliine adducts involving G:C base pairs.
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Affiliation(s)
- Nan Mei
- Division of Genetic and Reproductive Toxicology, National Center for Toxicological Research, Food and Drug Administration, Jefferson, Arkansas 72079, USA.
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Claxton LD, Matthews PP, Warren SH. The genotoxicity of ambient outdoor air, a review: Salmonella mutagenicity. MUTATION RESEARCH-REVIEWS IN MUTATION RESEARCH 2004; 567:347-99. [PMID: 15572287 DOI: 10.1016/j.mrrev.2004.08.002] [Citation(s) in RCA: 126] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2004] [Revised: 08/25/2004] [Accepted: 08/25/2004] [Indexed: 10/26/2022]
Abstract
Mutagens in urban air pollution come from anthropogenic sources (especially combustion sources) and are products of airborne chemical reactions. Bacterial mutation tests have been used for large, multi-site, and/or time series studies, for bioassay-directed fractionation studies, for identifying the presence of specific classes of mutagens, and for doing site- or source-comparisons for relative levels of airborne mutagens. Early research recognized that although carcinogenic PAHs were present in air samples they could not account for the majority of the mutagenic activity detected. The mutagenicity of airborne particulate organics is due to at least 500 identified compounds from varying chemical classes. Bioassay-directed fractionation studies for identifying toxicants are difficult to compare because they do not identify all of the mutagens present, and both the analytical and bioassay protocols vary from study to study. However, these studies show that the majority of mutagenicity is usually associated with moderately polar/highly polar classes of compounds that tend to contain nitroaromatic compounds, aromatic amines, and aromatic ketones. Smog chamber studies have shown that mutagenic aliphatic and aromatic nitrogen-containing compounds are produced in the atmosphere when organic compounds (even non-mutagenic compounds) are exposed to nitrogen oxides and sunlight. Reactions that occur in the atmosphere, therefore, can have a profound effect on the genotoxic burden of ambient air. This review illustrates that the mutagenesis protocol and tester strains should be selected based on the design and purpose of the study and that the correlation with animal cancer bioassay results depends upon chemical class. Future emphasis needs to be placed on volatile and semi-volatile genotoxicants, and on multi-national studies that identify, quantify, and apportion mutagenicity. Initial efforts at replacing the Salmonella assay for ambient air studies with some emerging technology should be initiated.
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Affiliation(s)
- Larry D Claxton
- Cellular Toxicology Branch, Environmental Carcinogenesis Division, US Environmental Protection Agency, Research Triangle Park, NC 27709, USA.
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Hill KA, Wang J, Farwell KD, Sommer SS. Spontaneous tandem-base mutations (TBM) show dramatic tissue, age, pattern and spectrum specificity. Mutat Res 2003; 534:173-86. [PMID: 12504766 DOI: 10.1016/s1383-5718(02)00277-2] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
To supplement a previous analysis of spontaneous tandem-base mutations (TBM) in the lacI gene of Big Blue((R)) mice, 2658 additional mutants were sequenced from 13 tissues and 44 spontaneous TBM were identified (tripling the sample size). Previous findings were confirmed and generalized and several new observations were made. TBM differ from single and other double mutations in that TBM frequency varies dramatically with tissue type. In certain tissues, most notably male germ cells, no TBM are observed despite screening as many as 26 million plaque forming units. TBM are most frequent in kidney and liver (3.45 and 2x10(-6), respectively), accounting for 7.6 and 4.8% of all mutational events in kidney and liver, respectively. There is a trend for elevated TBM frequency in thymic lymphomas in p53-deficient mice. TBM are more frequent in old age in both liver and kidney. TBM differ from single mutations and other double mutations because they display a marked difference in pattern and dramatic tissue specificity for target sequence. Five of the 78 possible TBM outcomes comprise 79% of those observed, and mutations at GG/CC predominate. TBM in mice were compared with TBM found in human mutation databases. TBM are also rare in the human germline (one in 5133 germline mutations reported in five human mutation databases). In general, the types of somatic TBM are similar in mice and humans except for an excess of TG/CA to CA/TG TBM in humans (TBM related to ultraviolet light-induced skin cancer were excluded). TBM may be the result of unknown mechanisms that may have some similarities in mice and humans.
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Affiliation(s)
- Kathleen A Hill
- Department of Molecular Genetics, Beckman Research Institute/City of Hope, Duarte, CA 91010-0269, USA
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Micillino JC, Coulais C, Binet S, Bottin MC, Keith G, Moulin D, Rihn BH. Lack of genotoxicity of bitumen fumes in transgenic mouse lung. Toxicology 2002; 170:11-20. [PMID: 11750079 DOI: 10.1016/s0300-483x(01)00507-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
During hot application of bitumen containing materials, e.g. in hot paving or roofing, fumes are emitted that contain polycyclic aromatic compounds. Previous studies with rodents exposed to bitumen and coal-tar fume condensates showed formation of DNA adducts. In order to clarify the genotoxicity of bitumen fumes, we designed a study by using mice carrying a reporter gene for mutagenesis analysis and exposed by nose-only to a constant and reproducible aerosol of bitumen fumes. We analyzed the genotoxic activity of inhaled bitumen fumes generated under those controlled conditions through the induction of mutation and DNA adducts in Big Blue mice. Mice were exposed to bitumen fumes (100 mg/m(3) total particulate matter) 6 h per day during 5 days by nose-only in an inhalation chamber designed in our laboratory. Following a 30-day fixation period, the experiment was terminated and lung DNA was extracted for mutant frequency and adduct determinations. The mutant frequency was determined using the cII and the lacI mutant analysis systems. In, addition, 61 and 54 mutants were sequenced in control and exposed groups, respectively. The study did not show any mutation or adduct induction in the exposed group compared to the control group: cII mutant frequencies were 11.0+/-4.5x10(-5) and 11.0+/-4.8x10(-5) in control and exposed lungs, respectively. Identically, using the lacI mutation detection system, the mutant frequencies were 6.4+/-3.1x10(-5) and 5.8+/-2.0x10(-5). The mutation spectra of both series were quite similar with regard to transition and transversion frequencies. The absence of genotoxicity in the group exposed to 100 mg/m(3) bitumen is discussed with regard to dosage of inhaled polycyclic aromatic compounds and species.
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Affiliation(s)
- Jean Claude Micillino
- Département Polluants et Santé, Institut National de Recherche et de Sécurité, Avenue de Bourgogne, 54501, Cedex, Vandoeuvre, France
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