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Shirato M, Takida Y, Kanno T, Matsuura H, Niwano Y, Minamide H, Nakamura K. Mutagenicity assessment of high-power 1.6-THz pulse laser radiation. Photochem Photobiol 2024; 100:146-158. [PMID: 37477119 DOI: 10.1111/php.13840] [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: 04/03/2023] [Revised: 06/20/2023] [Accepted: 07/08/2023] [Indexed: 07/22/2023]
Abstract
The effect of terahertz (THz) radiation has been studied in medicine. However, there is a lack of scientific information regarding its possible mutagenicity. Therefore, the present study aimed to assess the mutagenicity of 1.6 THz laser irradiation. The Ames test was conducted using five bacterial tester strains. The bacteria were subjected to (i) 1.6 THz laser irradiation at 3.8 mW/cm2 for 60 min using a tabletop THz pulse laser system, (ii) ultraviolet irradiation, (iii) treatment with positive control chemicals (positive control) or (iv) treatment with the solvent used in the positive control (negative control). After treatment, the bacterial suspensions were cultured on minimal glucose agar to determine the number of revertant colonies. In addition, the comet assay was performed using fibroblasts (V79) to assess possible DNA damage caused by the THz laser irradiation. The Ames test demonstrated that the THz laser irradiation did not increase the number of revertant colonies compared to that in the negative control group, whereas the ultraviolet irradiation and positive control treatment increased the number of revertant colonies. Thus, 1.6 THz laser irradiation is unlikely to be mutagenic. The comet assay additionally suggests that the THz laser irradiation unlikely induce cellular DNA damage.
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Affiliation(s)
- Midori Shirato
- Department of Advanced Free Radical Science, Tohoku University Graduate School of Dentistry, Sendai, Japan
| | - Yuma Takida
- RIKEN Center for Advanced Photonics, RIKEN, Sendai, Japan
| | - Taro Kanno
- Department of Advanced Free Radical Science, Tohoku University Graduate School of Dentistry, Sendai, Japan
| | | | | | | | - Keisuke Nakamura
- Department of Advanced Free Radical Science, Tohoku University Graduate School of Dentistry, Sendai, Japan
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Egorova OV, Suzina NE, Ilyushina NA. Salmonella mutant strains resistant to herbicides - Acetohydroxyacid synthase inhibitors and their use at the Ames test. Toxicol In Vitro 2023; 93:105699. [PMID: 37751784 DOI: 10.1016/j.tiv.2023.105699] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Revised: 09/08/2023] [Accepted: 09/22/2023] [Indexed: 09/28/2023]
Abstract
Cytotoxicity of some pesticides is a disadvantage for the Salmonella/microsome assay with regard to the equivalence assessment of pesticide technical grade active ingredients to the original products and detection of low-level impurities. The technical grade active ingredients (TGAIs) of pesticides from certain chemical classes were found to be toxic for Salmonella typhimurium strains. Among the highly cytotoxic compounds were sulfonylureas, which include 20 active ingredients. In addition, this class includes active pharmaceutical ingredients used for the manufacture of antidiabetics drugs. A traditional selection methodology was applied using the cultivation of S. typhimurium TA100 in the presence of high concentrations of thifensulfuronmethyl (TFSM) to obtain a resistant test strain insusceptible to sulfonylurea toxic effect. Two strains resistant not only to sulfonylureas (SFU) but also triazolepyrimidines were received. The first mutant strain (deposited as S. typhimurium VKPM B-14099 in the Russian National Collection of Industrial Microorganisms) demonstrated the TA100 phenotypic characteristics: hisG46, rfa, ΔuvrB-bio, pKM101. The second strain (deposited as S. typhimurium VKPM B-14359) showed the TA1535 phenotypic characteristics and probably lost the R-factor due to the selection using the poor Gm-media with TFSM. Positive controls caused pronounced mutagenic effects (±S9) in both strains, consequently the mutants did not lose the ability to respond to induction of the reverse gene mutations. The maximum non-cytotoxic concentrations of SFUs and triazole-pyrimidines for the Ames test strains did not exceed 0.05-0.125 mg/plate, while no evidence of cytotoxicity was observed for the mutants up to 5.0 mg/plate. Electron microscopy of the ultrathin sections of Salmonella cells grown with and without TFSM showed an obvious difference in the structure of the cell wall and cytoplasm in mutant and parental cultures. The concurrent resistance both to SFU and triazolepyrimidines was assumed to be mediated by the same mechanism of action of the pesticides from these classes - inhibition of acetohydroxyacid synthase. To confirm this hypothesis, the tests in the presence of branched-chain amino acids were carried out. The enrichment of agar with isoleucine prevented the toxic effects of SFU and triazolepyrimidines for all Ames test strains used in the study, while strong cytotoxicity was observed in the presence of valine and leucine. Considering the tolerance of strains both to SFU and triazolpyrimidines and the results with branched-chain amino acids, the modification of target acetohydroxyacid synthase was supposed the key to the acquired resistance. The new strains resistant to sulfonylureas and triazole-pyrimidines expands the possibilities to reveal mutagenic impurities that may occur in TGAIs in small amounts.
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Affiliation(s)
- Olga V Egorova
- Federal Budgetary Establishment of Science «Federal Scientific Center of Hygiene named after F.F.Erisman» of the Federal Service for Surveillance on Consumer Protection and Human Wellbeing, Mytischi 141014, Moscow Region, Russian Federation.
| | - Nataliya E Suzina
- G.K. Skryabin Institute of Biochemistry and Physiology of Microorganisms, Federal Research Center «Pushchino Center for Biological Research of the Russian Academy of Sciences», pr. Nauki, 5, Pushchino, Moscow Region, 142290, Russian Federation
| | - Nataliya A Ilyushina
- Federal Budgetary Establishment of Science «Federal Scientific Center of Hygiene named after F.F.Erisman» of the Federal Service for Surveillance on Consumer Protection and Human Wellbeing, Mytischi 141014, Moscow Region, Russian Federation
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Martus HJ, Zeller A, Kirkland D. International Workshops on Genotoxicity Testing (IWGT): Origins, achievements and ambitions. MUTATION RESEARCH. REVIEWS IN MUTATION RESEARCH 2023; 792:108469. [PMID: 37777464 DOI: 10.1016/j.mrrev.2023.108469] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 08/26/2023] [Indexed: 10/02/2023]
Abstract
Over the past thirty years, the International Workshops on Genotoxicity Testing (IWGT) became one of the leading groups in the field of regulatory genotoxicology, not only due to the diversity of participants with respect to geography and professional affiliation, but also due to the unique setup of recurring IWGT meetings every four years. The hallmarks of the IWGT process have been diligent initial planning approaches of the working groups, collection of data so as to stimulate data-driven discussions and debate, and striving to reach consensus recommendations. The scientific quality of the Working Groups (WGs) has been exceptional due to the selection of highly regarded experts on each topic. As a result, the IWGT working group reports have become important documents. The deliberations and publications have provided guidance on test systems and testing protocols that have influenced the development or revision of test guidelines of the Organisation for Economic Co-operation and Development (OECD), guidance by the International Council for Harmonisation (ICH), and strategic testing or data analysis approaches in general. This article summarizes the history of the IWGT, identifies some of its major achievements, and provides an outlook for the future.
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Affiliation(s)
| | - Andreas Zeller
- Pharmaceutical Sciences, pRED Innovation Center Basel, F. Hoffmann-La Roche Ltd, Grenzacherstrasse 124, CH-4070 Basel, Switzerland
| | - David Kirkland
- Kirkland Consulting, P O Box 79, Tadcaster LS24 0AS, United Kingdom
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Kanter J, Oronsky B, Reid T, Caroen S, Stirn M, Brinkhaus F, Kumar R, Stirn S. Explosive Hazards Identified during the Manufacture and Transportation of 1-Bromoacetyl-3,3-dinitroazetidine (RRx-001). Org Process Res Dev 2022. [DOI: 10.1021/acs.oprd.2c00109] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- James Kanter
- EpicentRx Inc. 11099 North Torrey Pines Road, Suite 160, La Jolla, California 92037, United States
| | - Bryan Oronsky
- EpicentRx Inc. 11099 North Torrey Pines Road, Suite 160, La Jolla, California 92037, United States
| | - Tony Reid
- EpicentRx Inc. 11099 North Torrey Pines Road, Suite 160, La Jolla, California 92037, United States
| | - Scott Caroen
- EpicentRx Inc. 11099 North Torrey Pines Road, Suite 160, La Jolla, California 92037, United States
| | - Meaghan Stirn
- EpicentRx Inc. 11099 North Torrey Pines Road, Suite 160, La Jolla, California 92037, United States
| | - Franck Brinkhaus
- EpicentRx Inc. 11099 North Torrey Pines Road, Suite 160, La Jolla, California 92037, United States
| | - Raj Kumar
- EpicentRx Inc. 11099 North Torrey Pines Road, Suite 160, La Jolla, California 92037, United States
| | - Scott Stirn
- EpicentRx Inc. 11099 North Torrey Pines Road, Suite 160, La Jolla, California 92037, United States
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Hakura A, Awogi T, Shiragiku T, Ohigashi A, Yamamoto M, Kanasaki K, Oka H, Dewa Y, Ozawa S, Sakamoto K, Kato T, Yamamura E. Bacterial mutagenicity test data: collection by the task force of the Japan pharmaceutical manufacturers association. Genes Environ 2021; 43:41. [PMID: 34593056 PMCID: PMC8482598 DOI: 10.1186/s41021-021-00206-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2021] [Accepted: 07/07/2021] [Indexed: 12/04/2022] Open
Abstract
Background Ames test is used worldwide for detecting the bacterial mutagenicity of chemicals. In silico analyses of bacterial mutagenicity have recently gained acceptance by regulatory agencies; however, current in silico models for prediction remain to be improved. The Japan Pharmaceutical Manufacturers Association (JPMA) organized a task force in 2017 in which eight Japanese pharmaceutical companies had participated. The purpose of this task force was to disclose a piece of pharmaceutical companies’ proprietary Ames test data. Results Ames test data for 99 chemicals of various chemical classes were collected for disclosure in this study. These chemicals are related to the manufacturing process of pharmaceutical drugs, including reagents, synthetic intermediates, and drug substances. The structure-activity (mutagenicity) relationships are discussed in relation to structural alerts for each chemical class. In addition, in silico analyses of these chemicals were conducted using a knowledge-based model of Derek Nexus (Derek) and a statistics-based model (GT1_BMUT module) of CASE Ultra. To calculate the effectiveness of these models, 89 chemicals for Derek and 54 chemicals for CASE Ultra were selected; major exclusions were the salt form of four chemicals that were tested both in the salt and free forms for both models, and 35 chemicals called “known” positives or negatives for CASE Ultra. For Derek, the sensitivity, specificity, and accuracy were 65% (15/23), 71% (47/66), and 70% (62/89), respectively. The sensitivity, specificity, and accuracy were 50% (6/12), 60% (25/42), and 57% (31/54) for CASE Ultra, respectively. The ratio of overall disagreement between the CASE Ultra “known” positives/negatives and the actual test results was 11% (4/35). In this study, 19 out of 28 mutagens (68%) were detected with TA100 and/or TA98, and 9 out of 28 mutagens (32%) were detected with either TA1535, TA1537, WP2uvrA, or their combination. Conclusion The Ames test data presented here will help avoid duplicated Ames testing in some cases, support duplicate testing in other cases, improve in silico models, and enhance our understanding of the mechanisms of mutagenesis. Supplementary Information The online version contains supplementary material available at 10.1186/s41021-021-00206-1.
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Affiliation(s)
- Atsushi Hakura
- Global Drug Safety, Eisai Co., Ltd., 5-1-3 Tokodai, Tsukuba, Ibaraki, 300-2635, Japan.
| | - Takumi Awogi
- Manufacturing Process Development Department, Otsuka Pharmaceutical Co., Ltd., 224-18 Hiraishi-Ebisuno, Kawauchi-cho, Tokushima-shi, Tokushima, 771-0182, Japan
| | - Toshiyuki Shiragiku
- Tokushima Research Institute, Otsuka Pharmaceutical Co., Ltd., 463-10 Kagasuno, Kawauchi-cho, Tokushima-shi, Tokushima, 771-0192, Japan
| | - Atsushi Ohigashi
- Process Chemistry Labs, Astellas Pharma Inc., 160-2 Akahama, Takahagi, Ibaraki, 318-0001, Japan
| | - Mika Yamamoto
- Drug Safety Research Labs, Astellas Pharma Inc., 21 Miyukigaoka, Tsukuba, Ibaraki, 305-8585, Japan
| | - Kayoko Kanasaki
- Laboratory for Drug Discovery and Development, Shionogi & Co., Ltd., 3-1-1 Futaba-cho, Osaka, Toyonaka-shi, 561-0825, Japan
| | - Hiroaki Oka
- Toxicology Laboratory, Taiho pharmaceutical Co., Ltd., 224-2 Ebisuno, Hiraishi, Kawauchi-cho, Tokushima, 771-0194, Japan
| | - Yasuaki Dewa
- Toxicology Research Laboratory, Kyorin Pharmaceutical Co., Ltd., 1848 Nogi, Nogi-machi, Shimotsuga-gun, Tochigi, 329-0114, Japan
| | - Shunsuke Ozawa
- Toxicology Research Laboratory, Kyorin Pharmaceutical Co., Ltd., 1848 Nogi, Nogi-machi, Shimotsuga-gun, Tochigi, 329-0114, Japan
| | - Kouji Sakamoto
- Drug Safety, Taisho Pharmaceutical Co., Ltd., 1-403, Yoshino-cho, Kita-ku, Saitama-shi, 331-9530, Japan
| | - Tatsuya Kato
- Safety Research Laboratories, Mitsubishi Tanabe Pharma Co., 2-2-50 Kawagishi, Toda-shi, Saitama, 335-8505, Japan
| | - Eiji Yamamura
- Safety Research Laboratories, Mitsubishi Tanabe Pharma Co., 2-2-50 Kawagishi, Toda-shi, Saitama, 335-8505, Japan
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Meng F, Mei N, Yan J, Guo X, Richter PA, Chen T, De M. Comparative potency analysis of whole smoke solutions in the bacterial reverse mutation test. Mutagenesis 2021; 36:321-329. [PMID: 34131742 PMCID: PMC8742878 DOI: 10.1093/mutage/geab021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Accepted: 06/11/2021] [Indexed: 11/13/2022] Open
Abstract
Short-term in vitro genotoxicity assays are useful tools to assess whether new and emerging tobacco products potentially have reduced toxicity. We previously demonstrated that potency ranking by benchmark dose (BMD) analysis quantitatively identifies differences among several known carcinogens and toxic chemicals representing different chemical classes found in cigarette smoke. In this study, six whole smoke solution (WSS) samples containing both the particulate and gas phases of tobacco smoke were generated from two commercial cigarette brands under different smoking-machine regimens. Sixty test cigarettes of each brand were machine-smoked according to the International Organization for Standardization (ISO) puffing protocol. In addition, either 60 or 20 test cigarettes of each brand were machine-smoked with the Canadian Intense (CI) puffing protocol. All six WSSs were evaluated in the bacterial reverse mutation (Ames) test using Salmonella typhimurium strains, in the presence or absence of S9 metabolic activation. The resulting S9-mediated mutagenic concentration-responses for the four WSSs from 60 cigarettes were then compared using BMD modelling analysis and the mutagenic potency expressed as number of revertants per μl of the WSS. The quantitative approaches resulted in a similar rank order of mutagenic potency for the Ames test in both TA98 and TA100. Under the conditions of this study, these results indicate that quantitative analysis of the Ames test data can discriminate between the mutagenic potencies of WSSs on the basis of smoking-machine regimen (ISO vs. CI), and cigarette product (differences in smoke chemistry).
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Affiliation(s)
- Fanxue Meng
- Division of Genetic and Molecular Toxicology, National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, AR 72079, USA
- Present address: 7870 Reflection Cove Dr., Fort Myers, FL 33907, USA
| | - Nan Mei
- Division of Genetic and Molecular Toxicology, National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, AR 72079, USA
| | - Jian Yan
- Division of Genetic and Molecular Toxicology, National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, AR 72079, USA
| | - Xiaoqing Guo
- Division of Genetic and Molecular Toxicology, National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, AR 72079, USA
| | - Patricia A. Richter
- Division of Nonclinical Science, Center for Tobacco Products, U.S. Food and Drug Administration, Silver Spring, MD 20993, USA
- Present address: Division of Global Health Protection, Centers for Disease Control and Prevention, Atlanta, GA 30341, USA
| | - Tao Chen
- Division of Genetic and Molecular Toxicology, National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, AR 72079, USA
| | - Mamata De
- Division of Nonclinical Science, Center for Tobacco Products, U.S. Food and Drug Administration, Silver Spring, MD 20993, USA
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Dantas FGDS, Castilho PFD, Almeida-Apolonio AAD, Araújo RPD, Oliveira KMPD. Mutagenic potential of medicinal plants evaluated by the Ames Salmonella/microsome assay: A systematic review. MUTATION RESEARCH-REVIEWS IN MUTATION RESEARCH 2020; 786:108338. [PMID: 33339578 DOI: 10.1016/j.mrrev.2020.108338] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Revised: 10/02/2020] [Accepted: 10/06/2020] [Indexed: 01/21/2023]
Abstract
The Ames test has become one of the most commonly used tests to assess the mutagenic potential of medicinal plants since they have several biological activities and thus have been used in traditional medicine and in the pharmaceutical industry as a source of raw materials. Accordingly, this review aims to report previous use of the Ames test to evaluate the mutagenic potential of medicinal plants. A database was constructed by curating literature identified by a search on the electronic databases Medline (via Pubmed), Science Direct, Scopus, and Web of Science from 1975 to April 2020, using the following terms: "genotoxicity tests" OR "mutagenicity tests" OR "Ames test" AND "medicinal plants." From the research, 239 articles were selected, including studies of 478 species distributed across 111 botanical families, with Fabaceae, Asteraceae and Lamiaceae being the most frequent. It was identified that 388 species were non-mutagenic. Of these, 21% (83/388) showed antimutagenic potential, most notable in the Lamiaceae family. The results also indicate that 18% (90/478) of the species were mutagenic, of which 54% were mutagenic in the presence and absence of S9. Strains TA98 and TA100 showed a sensitivity of 93% in detecting plant extracts with mutagenic potential. However, the reliability of many reviewed studies regarding the botanical extracts may be questioned due to technical issues, such as testing being performed only in the presence or absence of S9, use of maximum doses below 5 mg/plate and lack of information on the cytotoxicity of tested doses. These methodological aspects additionally demonstrated that a discussion about the doses used in research on mixtures, such as the ones assessed with botanical extracts and the most sensitive strains employed to detect the mutagenic potential, should be included in a possible update of the guidelines designed by the regulatory agencies.
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Affiliation(s)
- Fabiana Gomes da Silva Dantas
- Faculty of Health Sciences, Federal University of Grande Dourados, Dourados, MS, Brazil; Faculty of Biological and Environmental Sciences, Federal University of Grande Dourados, Dourados, MS, Brazil
| | | | | | - Renata Pires de Araújo
- Faculty of Biological and Environmental Sciences, Federal University of Grande Dourados, Dourados, MS, Brazil; Faculty of Exact Sciences and Technology, Federal University of Grande Dourados, Dourados, MS, Brazil
| | - Kelly Mari Pires de Oliveira
- Faculty of Health Sciences, Federal University of Grande Dourados, Dourados, MS, Brazil; Faculty of Biological and Environmental Sciences, Federal University of Grande Dourados, Dourados, MS, Brazil.
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Kauffmann K, Gremm L, Brendt J, Schiwy A, Bluhm K, Hollert H, Büchs J. Alternative type of Ames test allows for dynamic mutagenicity detection by online monitoring of respiration activity. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 726:137862. [PMID: 32481210 DOI: 10.1016/j.scitotenv.2020.137862] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Revised: 03/05/2020] [Accepted: 03/10/2020] [Indexed: 06/11/2023]
Abstract
The Ames test is the most commonly used mutagenicity test worldwide. It is based on a microbial system that uses histidine auxotrophic Salmonella typhimurium strains. Due to either spontaneous mutations or mutations induced by a mutagenic compound, the cells can regain their ability to grow without histidine supplementation. The degree of mutagenicity of a sample correlates with the number of cells that are able to grow in media that lack histidine. All test variants published up to now are endpoint determinations providing no information about cell growth and respiration activity during the cultivation time. This study aimed to develop an alternative type of Ames test by characterizing the respiration activity of Salmonella typhimurium over time for dynamic mutagenicity detection. It focuses on elucidating the mechanisms underlying this novel test system, and serves as a general proof of principle. Respiration activity (oxygen transfer and uptake rate) and biomass growth of Salmonella typhimurium TA 100 and TA 98 were mechanistically modeled to understand and predict the behavior of the bacteria during the Ames test. The results simulated by the model were experimentally validated by the online monitoring of respiration activity over cultivation time using a Respiration Activity MOnitoring System (RAMOS). The simulated prediction was observed to fit well to the experimental data. When a mutagenic compound was added, its mutagenicity could be detected online due to the elevated cell number and respiration of histidine prototrophic cells. Laborious manual evaluation of mutagenicity after cultivation is not necessary. Mutagenicity evaluation with the presented alternative Ames RAMOS test fitted well to results from an Ames fluctuation test. In the future, a miniaturized RAMOS device for microtiter plates should allow for a high-throughput Ames RAMOS test.
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Affiliation(s)
- Kira Kauffmann
- AVT-Chair for Biochemical Engineering, RWTH Aachen University, Forckenbeckstraße 51, 52074 Aachen, Germany.
| | - Lisa Gremm
- AVT-Chair for Biochemical Engineering, RWTH Aachen University, Forckenbeckstraße 51, 52074 Aachen, Germany.
| | - Julia Brendt
- Institute for Environmental Research, Department of Ecosystem Analysis, Worringerweg 1, 52074 Aachen, Germany.
| | - Andreas Schiwy
- Institute for Environmental Research, Department of Ecosystem Analysis, Worringerweg 1, 52074 Aachen, Germany; Department of Evolutionary Ecology and Environmental Toxicology, Goethe University Frankfurt, Max-von-Laue-Str. 13, 60438 Frankfurt am Main, Germany.
| | - Kerstin Bluhm
- Institute for Environmental Research, Department of Ecosystem Analysis, Worringerweg 1, 52074 Aachen, Germany.
| | - Henner Hollert
- Institute for Environmental Research, Department of Ecosystem Analysis, Worringerweg 1, 52074 Aachen, Germany; Department of Evolutionary Ecology and Environmental Toxicology, Goethe University Frankfurt, Max-von-Laue-Str. 13, 60438 Frankfurt am Main, Germany.
| | - Jochen Büchs
- AVT-Chair for Biochemical Engineering, RWTH Aachen University, Forckenbeckstraße 51, 52074 Aachen, Germany.
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Kauffmann K, Werner F, Deitert A, Finklenburg J, Brendt J, Schiwy A, Hollert H, Büchs J. Optimization of the Ames RAMOS test allows for a reproducible high-throughput mutagenicity test. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 717:137168. [PMID: 32084684 DOI: 10.1016/j.scitotenv.2020.137168] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Revised: 02/05/2020] [Accepted: 02/05/2020] [Indexed: 06/10/2023]
Abstract
The Ames test is one of the most widely used mutagenicity tests. It employs histidine auxotrophic bacteria, which can mutate back to histidine prototrophy and, thus, grow on a histidine deficient medium. These mutants develop predominantly after adding a mutagenic compound during an initial growth phase on 1 mg/L histidine. In the established test systems, an endpoint determination is performed to determine the relative number of mutants. An alternative Ames test, the Ames RAMOS test, has been developed, which enables the online detection of mutagenicity by monitoring respiration activity. The reproducibility of the newly developed test system was investigated. A strong dependence of the test results on the inoculum volume transferred from the preculture was found. The more inoculum was needed to reach the required initial OD, the more mutagenic a positive control was evaluated. This effect was attributed to the histidine transfer from the preculture to the original Ames RAMOS test. The same problem is evident in the Ames fluctuation test. High reproducibility of the Ames RAMOS test could be achieved by performing the preculture on minimal medium with a defined histidine concentration and termination after histidine depletion. By using 5 mg/L initial histidine within the minimal medium, a higher separation efficiency between negative control and mutagenic samples could be achieved. This separation efficiency could be further increased by lowering the cultivation temperature from 37 to 30 °C, i.e. lowering the maximum growth rate. The optimized Ames RAMOS test was then transferred into a 48-well microtiter plate format (μRAMOS) for obtaining a high throughput test. The online detection of mutagenicity leads to a reduction of working time in the laboratory. Due to the optimization of reproducibility and the increase in separation efficiency, a sound mutagenicity evaluation, even of weak mutagenic compounds, can be achieved.
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Affiliation(s)
- Kira Kauffmann
- AVT-Chair for Biochemical Engineering, RWTH Aachen University, Forckenbeckstraße 51, 52074 Aachen, Germany.
| | - Felix Werner
- AVT-Chair for Biochemical Engineering, RWTH Aachen University, Forckenbeckstraße 51, 52074 Aachen, Germany.
| | - Alexander Deitert
- AVT-Chair for Biochemical Engineering, RWTH Aachen University, Forckenbeckstraße 51, 52074 Aachen, Germany.
| | - Julian Finklenburg
- AVT-Chair for Biochemical Engineering, RWTH Aachen University, Forckenbeckstraße 51, 52074 Aachen, Germany.
| | - Julia Brendt
- Institute for Environmental Research, Department of Ecosystem Analysis, Worringerweg 1, 52074 Aachen, Germany.
| | - Andreas Schiwy
- Institute for Environmental Research, Department of Ecosystem Analysis, Worringerweg 1, 52074 Aachen, Germany.
| | - Henner Hollert
- Institute for Environmental Research, Department of Ecosystem Analysis, Worringerweg 1, 52074 Aachen, Germany.
| | - Jochen Büchs
- AVT-Chair for Biochemical Engineering, RWTH Aachen University, Forckenbeckstraße 51, 52074 Aachen, Germany.
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Schoeny R, Cross KP, DeMarini DM, Elespuru R, Hakura A, Levy DD, Williams RV, Zeiger E, Escobar PA, Howe JR, Kato M, Lott J, Moore MM, Simon S, Stankowski LF, Sugiyama KI, van der Leede BJM. Revisiting the bacterial mutagenicity assays: Report by a workgroup of the International Workshops on Genotoxicity Testing (IWGT). MUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2020; 849:503137. [PMID: 32087853 DOI: 10.1016/j.mrgentox.2020.503137] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Accepted: 01/09/2020] [Indexed: 11/26/2022]
Abstract
The International Workshop on Genotoxicity Testing (IWGT) meets every four years to obtain consensus on unresolved issues associated with genotoxicity testing. At the 2017 IWGT meeting in Tokyo, four sub-groups addressed issues associated with the Organization for Economic Cooperation and Development (OECD) Test Guideline TG471, which describes the use of bacterial reverse-mutation tests. The strains sub-group analyzed test data from >10,000 chemicals, tested additional chemicals, and concluded that some strains listed in TG471 are unnecessary because they detected fewer mutagens than other strains that the guideline describes as equivalent. Thus, they concluded that a smaller panel of strains would suffice to detect most mutagens. The laboratory proficiency sub-group recommended (a) establishing strain cell banks, (b) developing bacterial growth protocols that optimize assay sensitivity, and (c) testing "proficiency compounds" to gain assay experience and establish historical positive and control databases. The sub-group on criteria for assay evaluation recommended that laboratories (a) track positive and negative control data; (b) develop acceptability criteria for positive and negative controls; (c) optimize dose-spacing and the number of analyzable doses when there is evidence of toxicity; (d) use a combination of three criteria to evaluate results: a dose-related increase in revertants, a clear increase in revertants in at least one dose relative to the concurrent negative control, and at least one dose that produced an increase in revertants above control limits established by the laboratory from historical negative controls; and (e) establish experimental designs to resolve unclear results. The in silico sub-group summarized in silico utility as a tool in genotoxicity assessment but made no specific recommendations for TG471. Thus, the workgroup identified issues that could be addressed if TG471 is revised. The companion papers (a) provide evidence-based approaches, (b) recommend priorities, and (c) give examples of clearly defined terms to support revision of TG471.
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Affiliation(s)
- Rita Schoeny
- Rita Schoeny, LLC, Washington, DC 20002, United States.
| | - Kevin P Cross
- Leadscope, Inc., 1393 Dublin Road, Columbus, OH 43215, United States
| | - David M DeMarini
- U.S. Environmental Protection Agency, Research Triangle Park, NC 27711, United States
| | - Rosalie Elespuru
- U.S. Food and Drug Administration, Center for Devices and Radiological Health, Silver Spring, MD 20993, United States
| | - Atsushi Hakura
- Tsukuba Drug Safety, Eisai Co., Ltd., Tsukuba, Ibaraki, 300-2635, Japan
| | - Dan D Levy
- U.S. Food and Drug Administration, Center for Food Safety and Applied Nutrition, College Park, MD 20740 United States
| | | | - Errol Zeiger
- Errol Zeiger Consulting, 800 Indian Springs Road, Chapel Hill, NC 27514, United States
| | | | | | - Masayuki Kato
- CMIC Pharma Science Co., Ltd., Hokuto, Yamanashi, Japan
| | - Jasmin Lott
- Boehringer Ingelheim Pharma GmbH & Co., KG, Birkendorfer Strasse 65, 88397 Biberach an der Riss, Germany
| | - Martha M Moore
- Ramboll US Corporation Little Rock, AR 72223, United States
| | - Stephanie Simon
- Merck KGaA, Frankfurter Straβe 250, Darmstadt, 64293, Germany
| | - Leon F Stankowski
- Charles River Laboratories - Skokie, LLC, 8025 Lamon Ave., Skokie, IL 60077, United States
| | - Kei-Ichi Sugiyama
- Division of Genetics and Mutagenesis, National Institute of Health Sciences, Kawasaki, Kanagawa, 210-9501, Japan
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Shibata T, Yamagata T, Kawade A, Asakura S, Toritsuka N, Koyama N, Hakura A. Evaluation of acetone as a solvent for the Ames test. Genes Environ 2020; 42:3. [PMID: 31998422 PMCID: PMC6979378 DOI: 10.1186/s41021-020-0143-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Accepted: 01/13/2020] [Indexed: 11/13/2022] Open
Abstract
Background Acetone is a common alternative solvent used in the Ames test when test chemicals are unstable or poorly soluble in water or dimethyl sulfoxide (DMSO). Yet, there is a very limited number of studies evaluating acetone as a solvent in the modified Ames test with preincubation (preincubation test). Results We evaluated the acetone as a solvent for the preincubation test. Fourteen mutagens dissolved in acetone was added each to the reaction mixture at 2 different volumes (25 or 50 μL) to examine mutagenicity using bacterial test strains recommended in the Organization for Economic Cooperation and Development (OECD) test guideline 471, and compared with DMSO (100 μL). Cytotoxicity of acetone was also examined in these bacterial strains. TA1537 was most sensitive to the cytotoxicity of acetone, the degree of which was moderate and similar to DMSO in TA1537 without S9 mix. In other strains, cytotoxicity was limited to a mild degree with or without S9 mix. Cytotoxicity of acetone did not affect detection of mutagenicity of any mutagens; many of them being comparable or less mutagenic than those with DMSO. Conclusions These findings indicate that acetone is a viable candidate as a solvent for the preincubation test in the 5 bacterial strains.
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Affiliation(s)
- Tomomi Shibata
- Management Planning Department, Sunplanet Co., Ltd, 3-5-10 Otsuka, Bunkyo-ku, Tokyo, 112-0012 Japan
| | - Takeshi Yamagata
- Preclinical Safety Research Unit, Tsukuba R&D Supporting Division, Sunplanet Co., Ltd, 5-1-3 Tokodai, Tsukuba, Ibaraki 300-2635 Japan
| | - Akihiro Kawade
- Preclinical Safety Research Unit, Tsukuba R&D Supporting Division, Sunplanet Co., Ltd, 5-1-3 Tokodai, Tsukuba, Ibaraki 300-2635 Japan
| | - Shoji Asakura
- 3Global Drug Safety, Eisai Co., Ltd, 5-1-3 Tokodai, Tsukuba, Ibaraki 300-2635 Japan
| | - Naoki Toritsuka
- 3Global Drug Safety, Eisai Co., Ltd, 5-1-3 Tokodai, Tsukuba, Ibaraki 300-2635 Japan
| | - Naoki Koyama
- 3Global Drug Safety, Eisai Co., Ltd, 5-1-3 Tokodai, Tsukuba, Ibaraki 300-2635 Japan
| | - Atsushi Hakura
- 3Global Drug Safety, Eisai Co., Ltd, 5-1-3 Tokodai, Tsukuba, Ibaraki 300-2635 Japan
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Levy DD, Zeiger E, Escobar PA, Hakura A, van der Leede BJM, Kato M, Moore MM, Sugiyama KI. Recommended criteria for the evaluation of bacterial mutagenicity data (Ames test). Mutat Res 2019; 848:403074. [PMID: 31708073 DOI: 10.1016/j.mrgentox.2019.07.004] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Accepted: 07/11/2019] [Indexed: 10/26/2022]
Abstract
A committee was constituted within the International Workshop on Genetic Toxicology Testing (IWGT) to evaluate the current criteria for a valid Ames test and to provide recommendations for interpretation of test results. Currently, determination of a positive vs. a negative result is made by applying various data evaluation procedures for comparing dosed plates with the concurrent solvent control plates. These evaluation procedures include a requirement for a specific fold increase (2- or 3-fold, specific to the bacterial strain), formal statistical procedures, or subjective (expert judgment) evaluation. After extensive discussion, the workgroup was not able to reach consensus recommendations in favor of any of these procedures. There was a consensus that combining additional evaluation criteria to the comparison between dosed plates and the concurrent solvent control plates improves test interpretation. The workgroup recommended using these additional criteria because the induction of mutations is a continuum of responses and there is no biological relevance to a strict dividing line between a positive (mutagenic) and not-positive (nonmutagenic) response. The most useful additional criteria identified were a concentration-response relationship and consideration of a possible increase above the concurrent control in the context of the laboratory's historical solvent control values for the particular tester strain. The workgroup also emphasized the need for additional testing to resolve weak or inconclusive responses, usually with altered experimental conditions chosen based on the initial results. Use of these multiple criteria allowed the workgroup to reach consensus on definitions of "clear positive" and "clear negative" responses which would not require a repeat test for clarification. The workgroup also reached consensus on recommendations to compare the responses of concurrent positive and negative controls to historical control distributions for assay acceptability, and the use of control charts to determine the validity of the individual test.
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Affiliation(s)
- Dan D Levy
- US Food and Drug Administration, Center for Food Safety and Applied Nutrition, College Park, MD, 20740, USA.
| | - Errol Zeiger
- Errol Zeiger Consulting, Chapel Hill, NC, 27514, USA
| | | | - Atsushi Hakura
- Tsukuba Drug Safety, Eisai Co., Ltd., Tsukuba, Ibaraki, 300-2635, Japan
| | - Bas-Jan M van der Leede
- Non-Clinical Safety, Janssen Research & Development, a Division of Janssen Pharmaceutica N.V., Beerse, Belgium
| | - Masayuki Kato
- CMIC Pharma Science Co., Ltd., Hokuto, Yamanashi, Japan
| | | | - Kei-Ichi Sugiyama
- Division of Genetics and Mutagenesis, National Institute of Health Sciences, Kawasaki, Kanagawa, 210-9501, Japan
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