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Baptista FBO, da Silva AF, Cordeiro LM, de Souza LI, da Silveira TL, Soares MV, Michelotti P, Corte CLD, da Silva RS, Rodrigues OED, Arantes LP, Soares FAA. Biosafety assessment of novel organoselenium zidovudine derivatives in the Caenorhabditis elegans model. Toxicol Appl Pharmacol 2024; 491:117045. [PMID: 39127352 DOI: 10.1016/j.taap.2024.117045] [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: 05/22/2024] [Revised: 07/08/2024] [Accepted: 07/26/2024] [Indexed: 08/12/2024]
Abstract
Antiretrovirals have improved considerably since the introduction of 3'-azido-3'-deoxythymidine (zidovudine or AZT), a molecule with also anticancer effects. Subsequently, a variety of other nucleosides have been synthesized. However, these medications are often associated with serious adverse events and the onset or exacerbation of degenerative processes, diseases, and syndromes, affecting mainly the mitochondria. In this study, we used Caenorhabditis elegans to investigate the toxicity potential of AZT and three new organoselenium derivatives with modifications in the 5' position of the sugar ring in place of the 5'-OH group, with the insertion of a neutral, an electron-withdrawing and an electron-donating group attached to the aryl selenol moiety: 5'-seleno-(4-chloro-phenyl)-3-(amino)-thymidine (ASAT-4-Cl), 5'-seleno-(phenyl)-3-(amino)-thymidine (ASAT-Ph), and 5'-seleno-(4-methoxyphenyl)-3-(amino)- thymidine (ASAT-4-OMe). Analyzes included worm survival, behavior parameters, high-resolution respirometry, citrate synthase activity, and ATP levels. Although all compounds negatively affected C. elegans, ASAT-4-Cl and ASAT-Ph showed lower toxicity compared to AZT, especially in mitochondrial viability and ATP production. Therefore, more studies must be carried out on the use of these new compounds as pharmacological interventions.
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Affiliation(s)
- Fabiane Bicca Obetine Baptista
- Federal University of Santa Maria, Center for Natural and Exact Sciences, Department of Biochemistry and Molecular Biology, Postgraduate Program in Biological Sciences: Toxicological Biochemistry, Camobi, Zip code 97105-900 Santa Maria, RS, Brazil
| | - Aline Franzen da Silva
- Federal University of Santa Maria, Center for Natural and Exact Sciences, Department of Biochemistry and Molecular Biology, Postgraduate Program in Biological Sciences: Toxicological Biochemistry, Camobi, Zip code 97105-900 Santa Maria, RS, Brazil
| | - Larissa Marafiga Cordeiro
- Federal University of Santa Maria, Center for Natural and Exact Sciences, Department of Biochemistry and Molecular Biology, Postgraduate Program in Biological Sciences: Toxicological Biochemistry, Camobi, Zip code 97105-900 Santa Maria, RS, Brazil
| | - Larissa Ilha de Souza
- Federal University of Santa Maria, Center for Natural and Exact Sciences, Department of Biochemistry and Molecular Biology, Postgraduate Program in Biological Sciences: Toxicological Biochemistry, Camobi, Zip code 97105-900 Santa Maria, RS, Brazil
| | - Tássia Limana da Silveira
- Federal University of Santa Maria, Center for Natural and Exact Sciences, Department of Biochemistry and Molecular Biology, Postgraduate Program in Biological Sciences: Toxicological Biochemistry, Camobi, Zip code 97105-900 Santa Maria, RS, Brazil
| | - Marcell Valandro Soares
- Federal University of Santa Maria, Center for Natural and Exact Sciences, Department of Biochemistry and Molecular Biology, Postgraduate Program in Biological Sciences: Toxicological Biochemistry, Camobi, Zip code 97105-900 Santa Maria, RS, Brazil
| | - Paula Michelotti
- Federal University of Santa Maria, Center for Natural and Exact Sciences, Department of Biochemistry and Molecular Biology, Postgraduate Program in Biological Sciences: Toxicological Biochemistry, Camobi, Zip code 97105-900 Santa Maria, RS, Brazil
| | - Cristiane Lenz Dalla Corte
- Federal University of Santa Maria, Center for Natural and Exact Sciences, Department of Biochemistry and Molecular Biology, Postgraduate Program in Biological Sciences: Toxicological Biochemistry, Camobi, Zip code 97105-900 Santa Maria, RS, Brazil
| | - Rafael Santos da Silva
- Federal University of Santa Maria, Center for Natural and Exact Sciences, Department of Chemistry, Postgraduate Program in Extension and Research in the Field of Organic Chemistry, Camobi, Zip code 97105-900 Santa Maria, RS, Brazil
| | - Oscar Endrigo Dorneles Rodrigues
- Federal University of Santa Maria, Center for Natural and Exact Sciences, Department of Chemistry, Postgraduate Program in Extension and Research in the Field of Organic Chemistry, Camobi, Zip code 97105-900 Santa Maria, RS, Brazil
| | - Leticia Priscilla Arantes
- State University of Minas Gerais, Department of Biomedical Sciences and Health, Belo Horizonte, Zip code 37900-106 Passos, MG, Brazil
| | - Félix Alexandre Antunes Soares
- Federal University of Santa Maria, Center for Natural and Exact Sciences, Department of Biochemistry and Molecular Biology, Postgraduate Program in Biological Sciences: Toxicological Biochemistry, Camobi, Zip code 97105-900 Santa Maria, RS, Brazil.
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Sule RO, Condon L, Gomes AV. A Common Feature of Pesticides: Oxidative Stress-The Role of Oxidative Stress in Pesticide-Induced Toxicity. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2022; 2022:5563759. [PMID: 35096268 PMCID: PMC8791758 DOI: 10.1155/2022/5563759] [Citation(s) in RCA: 119] [Impact Index Per Article: 59.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/28/2021] [Accepted: 12/17/2021] [Indexed: 12/16/2022]
Abstract
Pesticides are important chemicals or biological agents that deter or kill pests. The use of pesticides has continued to increase as it is still considered the most effective method to reduce pests and increase crop growth. However, pesticides have other consequences, including potential toxicity to humans and wildlife. Pesticides have been associated with increased risk of cardiovascular disease, cancer, and birth defects. Labels on pesticides also suggest limiting exposure to these hazardous chemicals. Based on experimental evidence, various types of pesticides all seem to have a common effect, the induction of oxidative stress in different cell types and animal models. Pesticide-induced oxidative stress is caused by both reactive oxygen species (ROS) and reactive nitrogen species (RNS), which are associated with several diseases including cancer, inflammation, and cardiovascular and neurodegenerative diseases. ROS and RNS can activate at least five independent signaling pathways including mitochondrial-induced apoptosis. Limited in vitro studies also suggest that exogenous antioxidants can reduce or prevent the deleterious effects of pesticides.
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Affiliation(s)
- Rasheed O. Sule
- Department of Neurobiology, Physiology and Behavior, University of California, Davis, Davis, CA 95616, USA
| | - Liam Condon
- Department of Neurobiology, Physiology and Behavior, University of California, Davis, Davis, CA 95616, USA
| | - Aldrin V. Gomes
- Department of Neurobiology, Physiology and Behavior, University of California, Davis, Davis, CA 95616, USA
- Department of Physiology and Membrane Biology, University of California, Davis, Davis, CA 95616, USA
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Hiding in Plain Sight: Modern Thiamine Deficiency. Cells 2021; 10:cells10102595. [PMID: 34685573 PMCID: PMC8533683 DOI: 10.3390/cells10102595] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Revised: 09/22/2021] [Accepted: 09/23/2021] [Indexed: 12/13/2022] Open
Abstract
Thiamine or vitamin B1 is an essential, water-soluble vitamin required for mitochondrial energetics—the production of adenosine triphosphate (ATP). It is a critical and rate-limiting cofactor to multiple enzymes involved in this process, including those at the entry points and at critical junctures for the glucose, fatty acid, and amino acid pathways. It has a very short half-life, limited storage capacity, and is susceptible to degradation and depletion by a number of products that epitomize modern life, including environmental and pharmaceutical chemicals. The RDA for thiamine is 1.1–1.2 mg for adult females and males, respectively. With an average diet, even a poor one, it is not difficult to meet that daily requirement, and yet, measurable thiamine deficiency has been observed across multiple patient populations with incidence rates ranging from 20% to over 90% depending upon the study. This suggests that the RDA requirement may be insufficient to meet the demands of modern living. Inasmuch as thiamine deficiency syndromes pose great risk of chronic morbidity, and if left untreated, mortality, a more comprehensive understanding thiamine chemistry, relative to energy production, modern living, and disease, may prove useful.
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Miller JGP, Jamwal A, Ilnytskyy Y, Hontela A, Wiseman SB. Dicamba elevates concentrations of S-adenosyl methionine but does not induce oxidative stress or alter DNA methylation in rainbow trout (Oncorhynchus mykiss) hepatocytes. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY D-GENOMICS & PROTEOMICS 2020; 36:100744. [PMID: 32950925 DOI: 10.1016/j.cbd.2020.100744] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Revised: 08/04/2020] [Accepted: 09/07/2020] [Indexed: 02/05/2023]
Abstract
Dicamba is a benzoic acid herbicide used to target woody and broadleaf weeds in industrial, domestic, and municipal spheres. Because of its widespread use, dicamba is frequently detected in surface waters near sites of application. However, little is known regarding the effects of dicamba on freshwater fishes. In the present study, primary cultures of hepatocytes from rainbow trout (Oncorhynchus mykiss) were exposed to either an environmentally relevant (0.22 or 2.2 μg L-1) or supra-environmental (22 μg L-1) concentration of dicamba for 48 h to investigate if oxidative stress is a mechanism of toxicity. mRNA abundances of genes involved in the response to oxidative stress, levels of lipid peroxidation, and concentrations of glutathione and s-adenosyl methionine (SAM) were quantified. Results indicate that dicamba does not induce oxidative stress. However, exposure to 2.2 μg L-1 of dicamba did cause a 5.24-fold increase in concentrations of SAM. To investigate the mechanisms of increased SAM, effects of dicamba on global and genome-wide DNA methylation were quantified. Dicamba did not cause changes to DNA methylation. Overall, dicamba was not acutely toxic to hepatocytes and did not cause oxidative stress or changes in DNA methylation at environmentally relevant concentrations.
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Affiliation(s)
- Justin G P Miller
- Department of Biological Sciences, University of Lethbridge, Lethbridge, Alberta, Canada
| | - Ankur Jamwal
- Department of Biological Sciences, University of Lethbridge, Lethbridge, Alberta, Canada
| | - Yaroslav Ilnytskyy
- Department of Biological Sciences, University of Lethbridge, Lethbridge, Alberta, Canada
| | - Alice Hontela
- Department of Biological Sciences, University of Lethbridge, Lethbridge, Alberta, Canada; Water Institute for Sustainable Environments (WISE), University of Lethbridge, Lethbridge, Alberta, Canada
| | - Steve B Wiseman
- Department of Biological Sciences, University of Lethbridge, Lethbridge, Alberta, Canada; Water Institute for Sustainable Environments (WISE), University of Lethbridge, Lethbridge, Alberta, Canada.
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Moon JM, Chun BJ. Clinical characteristics of patients after dicamba herbicide ingestion. Clin Toxicol (Phila) 2013; 52:48-53. [PMID: 24351123 DOI: 10.3109/15563650.2013.870342] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
OBJECTIVE Despite a widespread use of dicamba herbicide and numerous animal model studies, there had not been studies on acute toxicity of this chemical compound in human subjects following ingestion. Therefore, this study was conducted to investigate clinical characteristics of dicamba poisoning and to guide physicians treating patients intoxicated with dicamba herbicide. MATERIAL AND METHOD A retrospective observational case series was conducted for 14 patients with history of dicamba herbicide ingestion. Data were collected for clinical manifestation, patient management, and final outcome. RESULT The most common symptom was altered mental state (Glasgow Coma Scale ≤ 14). Laboratory abnormalities were elevations in lactate, and creatine kinase, metabolic acidosis (pH < 7.35, and HCO3(-) < 20 mmol/L), and elevated lipase. QTc prolongation was commonly observed. These abnormal clinical findings had normalized within two days of supportive treatment after dicamba ingestion. One patient did demonstrate corrosive esophagitis. DISCUSSION AND CONCLUSION Acute toxicity of dicamba herbicide in human following oral exposure was manageable with supportive treatment. However, physician should take into account for corrosive effect on GI tract, rhabdomyolysis, or acute pancreatitis.
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Affiliation(s)
- J M Moon
- Department of Emergency Medicine, Chonnam National University Medical School , Gwangju , South Korea
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Oliveira MM, Teixeira JC, Vasconcelos-Nóbrega C, Felix LM, Sardão VA, Colaço AA, Oliveira PA, Peixoto FP. Mitochondrial and liver oxidative stress alterations induced by N-butyl-N-(4-hydroxybutyl)nitrosamine: relevance for hepatotoxicity. J Appl Toxicol 2011; 33:434-43. [PMID: 22095756 DOI: 10.1002/jat.1763] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2011] [Revised: 09/03/2011] [Accepted: 09/27/2011] [Indexed: 11/06/2022]
Abstract
The most significant toxicological effect of nitrosamines like N-butyl-N-(4-hydroxybutyl)nitrosamine (BBN) is their carcinogenic activity, which may result from exposure to a single large dose or from chronic exposure to relatively small doses. However, its effects on mitochondrial liver bioenergetics were never investigated. Liver is the principal organ responsible for BBN metabolic activation, and mitochondria have a central function in cellular energy production, participating in multiple metabolic pathways. Therefore any negative effect on mitochondrial function may affect cell viability. In the present work, ICR male mice were given 0.05% of BBN in drinking water for a period of 12 weeks and were sacrificed one week later. Mitochondrial physiology was characterized in BBN- and control-treated mice. Transmembrane electric potential developed by mitochondria was significantly affected when pyruvate-malate was used, with an increase in state 4 respiration observed for pyruvate-malate (46%) and succinate (38%). A decrease in the contents of one subunit of mitochondrial complex I and in one subunit of mitochondrial complex IV was also observed. In addition, the activity of both complexes I and II was also decreased by BBN treatment. The treatment with BBN increases the susceptibility of liver mitochondria to the opening of the mitochondrial permeability transition pore. This susceptibility could be related with the increase in the production of H2 O2 by mitochondria and increased oxidative stress confirmed by augmented susceptibility to lipid peroxidation. These results lead to the conclusion that hepatic mitochondria are one primary target for BBN toxic action during liver metabolism.
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Affiliation(s)
- Maria M Oliveira
- Chemistry Department, CQVR, University of Trás-os-Montes and Alto Douro, 5001-801, Vila Real, Portugal
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Are fentanyl and remifentanil safe opioids for rat brain mitochondrial bioenergetics? Mitochondrion 2009; 9:247-53. [DOI: 10.1016/j.mito.2009.03.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2008] [Revised: 03/03/2009] [Accepted: 03/10/2009] [Indexed: 11/21/2022]
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Martins F, Gomes-Laranjo J, Amaral C, Almeida J, Peixoto F. Evaluation of olive oil mill wastewaters acute toxicity: a study on the mitochondrial bioenergetics. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2008; 69:480-7. [PMID: 17659777 DOI: 10.1016/j.ecoenv.2007.05.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2006] [Revised: 04/11/2007] [Accepted: 05/04/2007] [Indexed: 05/16/2023]
Abstract
Acute toxicity of olive mill wastewaters (OMW), collected from a continuous olive mill, was evaluated in rat liver mitochondrial bioenergetics. Inhibition of respiratory activities in state 4, state 3, and uncoupled respiration are essentially mediated through partial inhibitions of mitochondrial complexes II and III. ATPase activity was considerably less depressed by OMW than ATP synthase activity (a difference of 42%). The inhibition observed on ATP synthase is mostly the result of an inhibition on the redox complexes. Ultimately, the OMW-induced loss of phosphorylation capacity was not only the result of a direct effect of OMW on the enzymatic complex (F(0)-F(1) ATPase), but also the result of a deleterious effect on the integrity of the mitochondrial membrane, which can promote an inhibition of the respiratory complexes and an increase of the proton permeability of the inner membrane.
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Affiliation(s)
- F Martins
- Chemistry Department, CECAV, University of Trás-os-Montes and Alto Douro, 5001 Vila Real, Portugal
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González NV, Soloneski S, Larramendy ML. Genotoxicity analysis of the phenoxy herbicide dicamba in mammalian cells in vitro. Toxicol In Vitro 2006; 20:1481-7. [PMID: 16828255 DOI: 10.1016/j.tiv.2006.05.001] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2006] [Revised: 05/02/2006] [Accepted: 05/03/2006] [Indexed: 11/25/2022]
Abstract
The cytogenetic effects exerted by the phenoxy herbicide dicamba and one of its commercial formulations banvel (57.71% dicamba) were studied in in vitro whole blood human lymphocyte cultures. The genotoxicity of herbicides was measured by analysis of the frequency of sister chromatid exchanges (SCEs) and cell-cycle progression assays. Both dicamba and banvel activities were tested within 10.0-500.0 microg/ml doses range. Only concentrations of 200.0 microg/ml of dicamba and 500.0 microg/ml of banvel induced a significant increase in SCE frequency over control values. The highest dose of dicamba tested (500.0 microg/ml) resulted in cell culture cytotoxicity. The cell-cycle kinetics was affected by both test compounds since a significant delay in cell-cycle progression and a significant reduction of the proliferative rate index were observed after the treatment with 100.0 and 200.0 microg/ml of dicamba and 200.0 and 500.0 microg/ml of banvel. For both chemicals, a progressive dose-related inhibition of the mitotic activity of cultures was observed. Moreover, only the mitotic activity statistically differed from control values when doses of both chemicals higher than 100.0 microg/ml were employed. On the basis of our results, the herbicide dicamba is a DNA damage agent and should be considered as a potentially hazardous compound to humans.
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Affiliation(s)
- N V González
- Cátedra de Citología, Facultad de Ciencias Naturales y Museo, Universidad Nacional de La Plata, Calle 64 Nro. 3 esq. 120, 1900 La Plata, Argentina.
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Betancourt M, Reséndiz A, Fierro ECYR. Effect of two insecticides and two herbicides on the porcine sperm motility patterns using computer-assisted semen analysis (CASA) in vitro. Reprod Toxicol 2006; 22:508-12. [PMID: 16713176 DOI: 10.1016/j.reprotox.2006.03.001] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2005] [Revised: 02/10/2006] [Accepted: 03/03/2006] [Indexed: 12/26/2022]
Abstract
The recent decline in sperm concentration observed in men has developed over a short period of time, suggesting that it could be the result of environmental factors. The present study has evaluated the effects of insecticides Malathion and Diazinon, and herbicides Atrazine and Fenoxaprop-Ethyl on porcine sperm viability and motility patterns in vitro using the eosin-nigrosin staining and a computer-assisted semen analyzer (CASA), respectively. Malathion and Fenoxaprop-Ethyl exerted more deleterious effects than Diazinon and Atrazine. Progressive sperm motility was strongly affected whereas the effect on sperm viability was less pronounced. This suggests that a reduction of sperm motility is not necessarily the result of sperm death. Since sperm motility is dependent on energy metabolism the mechanism of action of these pesticides might be mediated at the level of the mitochondrion, producing a delay in motility and eventual cell death.
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Affiliation(s)
- Miguel Betancourt
- Departamento de Ciencias de la Salud, Universidad Autónoma Metropolitana-Iztapalapa, San Rafael Atlixco 186, CP 09340, DF, México.
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Četkauskaitė A, Zimkus A, Borovik J. Simultaneous measurements of mitochondrial trans‐membrane electric potential and oxygen consumption as biosensors for ecotoxicological research. ACTA ACUST UNITED AC 2006. [DOI: 10.1080/00207230600787836] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Peixoto F. Comparative effects of the Roundup and glyphosate on mitochondrial oxidative phosphorylation. CHEMOSPHERE 2005; 61:1115-22. [PMID: 16263381 DOI: 10.1016/j.chemosphere.2005.03.044] [Citation(s) in RCA: 150] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2004] [Revised: 02/24/2005] [Accepted: 03/16/2005] [Indexed: 05/03/2023]
Abstract
The potential toxicity of the herbicide Roundup and its fundamental substance (glyphosate) was tested in bioenergetic functions of isolated rat liver mitochondria. Roundup stimulates succinate-supported respiration twice, with simultaneous collapse of transmembrane electrical potential, while glyphosate used in the same concentrations does not induce any significant effect. Additionally, Roundup depresses state 3 respiration by about 40%, at 15 mM, whereas uncoupled respiration in the presence of FCCP is depressed by about 50%. Depression of uncoupled respiratory activity is mediated through partial inhibition of mitochondrial complexes II and III, but not of complex IV. The phosphorylative system was affected by both a direct and an indirect effect on the F0F1 ATPase activity. The addition of uncoupled concentrations of Roundup to Ca2+-loaded mitochondria treated with Ruthenium Red resulted in non-specific membrane permeabilization, as evidenced by mitochondrial swelling in isosmotic sucrose medium. Therefore, the uncoupling of oxidative phosphorylation is also related to the non-specific membrane permeabilization induced by Roundup. Glyphosate alone does not show any relevant effect on the mitochondrial bioenergetics, in opposition to Roundup formulation products. The differences in the toxicity observed could be either attributed to some products of Roundup or to a synergic effect of glyphosate and formulation products. Bearing in mind that mitochondria is provided with a variety of bioenergetic functions mandatory for the regulation of intracellular aerobic energy production and electrolyte homeostasis, these results question the safety of Roundup on animal health.
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Affiliation(s)
- Francisco Peixoto
- Departamento de Química, Universidade de Trás-os-Montes e Alto Douro, 5001 Vila Real, Portugal.
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O'Looney N, Fry SC. The novel herbicide oxaziclomefone inhibits cell expansion in maize cell cultures without affecting turgor pressure or wall acidification. THE NEW PHYTOLOGIST 2005; 168:323-9. [PMID: 16219072 DOI: 10.1111/j.1469-8137.2005.01501.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Oxaziclomefone [OAC; IUPAC name 3-(1-(3,5-dichlorophenyl)-1-methylethyl)-3,4-dihydro-6-methyl-5-phenyl-2H-1,3-oxazin-4-one] is a new herbicide that inhibits cell expansion in grass roots. Its effects on cell cultures and mode of action were unknown. In principle, cell expansion could be inhibited by a decrease in either turgor pressure or wall extensibility. Cell expansion was estimated as settled cell volume; cell division was estimated by cell counting. Membrane permeability to water was measured by a novel method involving simultaneous assay of the efflux of (3)H(2)O and [(14)C]mannitol from a 'bed' of cultured cells. Osmotic potential was measured by depression of freezing point. OAC inhibited cell expansion in cultures of maize (Zea mays), spinach (Spinacia oleracea) and rose (Rosa sp.), with an ID(50) of 5, 30 and 250 nm, respectively. In maize cultures, OAC did not affect cell division for the first 40 h. It did not affect the osmotic potential of cell sap or culture medium, nor did it impede water transport across cell membranes. It did not affect cells' ability to acidify the apoplast (medium), which may be necessary for 'acid growth'. As OAC did not diminish turgor pressure, its ability to inhibit cell expansion must depend on changes in wall extensibility. It could be a valuable tool for studies on cell expansion.
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Affiliation(s)
- Nichola O'Looney
- The Edinburgh Cell Wall Group, Institute of Molecular Plant Sciences, The University of Edinburgh, The King's Buildings, UK
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