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Forsten E, Finger M, Scholand T, Deitert A, Kauffmann K, Büchs J. Inoculum cell count influences separation efficiency and variance in Ames plate incorporation and Ames RAMOS test. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 905:167035. [PMID: 37709100 DOI: 10.1016/j.scitotenv.2023.167035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Revised: 08/29/2023] [Accepted: 09/11/2023] [Indexed: 09/16/2023]
Abstract
The Ames test is one of the most applied tools in mutagenicity testing of chemicals ever since its introduction by Ames et al. in the 1970s. Its principle is based on histidine auxotrophic bacteria that regain prototrophy through reverse mutations. In the presence of a mutagen, more reverse mutations occur that become visible as increased bacterial growth on medium without histidine. Many miniaturized formats of the Ames test have emerged to enable the testing of environmental water samples, increase experimental throughput, and lower the required amounts of test substances. However, most of these formats still rely on endpoint determinations. In contrast, the recently introduced Ames RAMOS test determines mutagenicity through online monitoring of the oxygen transfer rate. In this study, the oxygen transfer rate of Salmonella typhimurium TA100 during the Ames plate incorporation test was monitored and compared to the Ames RAMOS test to prove its validity further. Furthermore, the Ames RAMOS test in 96-well scale is newly introduced. For both the Ames plate incorporation and the Ames RAMOS test, the influence of the inoculum cell count on the negative control was highlighted: A lower inoculum cell count led to a higher coefficient of variation. However, a lower inoculum cell count also led to a higher separation efficiency in the Ames RAMOS test and, thus, to better detection of a mutagenic substance at lower concentrations.
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Affiliation(s)
- Eva Forsten
- AVT - Biochemical Engineering, RWTH Aachen University, Aachen, Germany
| | - Maurice Finger
- AVT - Biochemical Engineering, RWTH Aachen University, Aachen, Germany
| | - Theresa Scholand
- AVT - Biochemical Engineering, RWTH Aachen University, Aachen, Germany
| | - Alexander Deitert
- AVT - Biochemical Engineering, RWTH Aachen University, Aachen, Germany
| | - Kira Kauffmann
- AVT - Biochemical Engineering, RWTH Aachen University, Aachen, Germany
| | - Jochen Büchs
- AVT - Biochemical Engineering, RWTH Aachen University, Aachen, Germany.
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Lugo L, Venegas C, Guarin Trujillo E, Diaz Granados-Ramírez MA, Martin A, Vesga FJ, Pérez-Flórez A, Celis C. Ecotoxicology Evaluation of a Fenton-Type Process Catalyzed with Lamellar Structures Impregnated with Fe or Cu for the Removal of Amoxicillin and Glyphosate. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2023; 20:7172. [PMID: 38131723 PMCID: PMC10743043 DOI: 10.3390/ijerph20247172] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Revised: 11/10/2023] [Accepted: 11/28/2023] [Indexed: 12/23/2023]
Abstract
Antibiotics and pesticides, as well as various emerging contaminants that are present in surface waters, raise significant environmental concerns. Advanced oxidation processes, which are employed to eliminate these substances, have demonstrated remarkable effectiveness. However, during the degradation process, by-products that are not completely mineralized are generated, posing a substantial risk to aquatic ecosystem organisms; therefore, it is crucial to assess effluent ecotoxicity following treatment. This study aimed to assess the toxicity of effluents produced during the removal of amoxicillin and glyphosate with a Fenton-type process using a laminar structure catalyzed with iron (Fe) and copper (Cu). The evaluation included the use of Daphnia magna, Selenastrum capricornutum, and Lactuca sativa, and mutagenicity testing was performed using strains TA98 and TA100 of Salmonella typhimurium. Both treated and untreated effluents exhibited inhibitory effects on root growth in L. sativa, even at low concentrations ranging from 1% to 10% v/v. Similarly, negative impacts on the growth of algal cells of S. capricornutum were observed at concentrations as low as 0.025% v/v, particularly in cases involving amoxicillin-copper (Cu) and glyphosate with copper (Cu) and iron (Fe). Notably, in the case of D. magna, mortality was noticeable even at concentrations of 10% v/v. Additionally, the treatment of amoxicillin with double-layer hydroxides of Fe and Cu resulted in mutagenicity (IM ≥ 2.0), highlighting the necessity to treat the effluent further from the advanced oxidation process to reduce ecological risks.
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Affiliation(s)
- Lorena Lugo
- Department of Chemistry, Research Line in Environmental and Materials Technology (ITAM), Pontificia Universidad Javeriana, Carrera 7 No. 43–82, Bogotá 110231, Colombia; (L.L.); (A.M.); (A.P.-F.)
| | - Camilo Venegas
- Department of Microbiology, School of Sciences, Microbiological Quality of Water and Sludge (CMAL), Pontificia Universidad Javeriana, Carrera 7 No. 43-82, Bogotá 110231, Colombia; (C.V.); (E.G.T.); (M.A.D.G.-R.); (F.-J.V.)
| | - Elizabeth Guarin Trujillo
- Department of Microbiology, School of Sciences, Microbiological Quality of Water and Sludge (CMAL), Pontificia Universidad Javeriana, Carrera 7 No. 43-82, Bogotá 110231, Colombia; (C.V.); (E.G.T.); (M.A.D.G.-R.); (F.-J.V.)
| | - Maria Alejandra Diaz Granados-Ramírez
- Department of Microbiology, School of Sciences, Microbiological Quality of Water and Sludge (CMAL), Pontificia Universidad Javeriana, Carrera 7 No. 43-82, Bogotá 110231, Colombia; (C.V.); (E.G.T.); (M.A.D.G.-R.); (F.-J.V.)
| | - Alison Martin
- Department of Chemistry, Research Line in Environmental and Materials Technology (ITAM), Pontificia Universidad Javeriana, Carrera 7 No. 43–82, Bogotá 110231, Colombia; (L.L.); (A.M.); (A.P.-F.)
| | - Fidson-Juarismy Vesga
- Department of Microbiology, School of Sciences, Microbiological Quality of Water and Sludge (CMAL), Pontificia Universidad Javeriana, Carrera 7 No. 43-82, Bogotá 110231, Colombia; (C.V.); (E.G.T.); (M.A.D.G.-R.); (F.-J.V.)
| | - Alejandro Pérez-Flórez
- Department of Chemistry, Research Line in Environmental and Materials Technology (ITAM), Pontificia Universidad Javeriana, Carrera 7 No. 43–82, Bogotá 110231, Colombia; (L.L.); (A.M.); (A.P.-F.)
| | - Crispín Celis
- Department of Chemistry, Research Line in Environmental and Materials Technology (ITAM), Pontificia Universidad Javeriana, Carrera 7 No. 43–82, Bogotá 110231, Colombia; (L.L.); (A.M.); (A.P.-F.)
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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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