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Pereira SP, Santos SMA, Fernandes MAS, Deus CM, Martins JD, Pedroso de Lima MC, Vicente JAF, Videira RA, Jurado AS. Improving pollutants environmental risk assessment using a multi model toxicity determination with in vitro, bacterial, animal and plant model systems: The case of the herbicide alachlor. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2021; 286:117239. [PMID: 33990048 DOI: 10.1016/j.envpol.2021.117239] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Revised: 04/20/2021] [Accepted: 04/22/2021] [Indexed: 06/12/2023]
Abstract
Several environmental pollutants, including pesticides, herbicides and persistent organic pollutants play an important role in the development of chronic diseases. However, most studies have examined environmental pollutants toxicity in target organisms or using a specific toxicological test, losing the real effect throughout the ecosystem. In this sense an integrative environmental risk of pollutants assessment, using different model organisms is necessary to predict the real impact in the ecosystem and implications for target and non-target organisms. The objective of this study was to use alachlor, a chloroacetanilide herbicide responsible for chronic toxicity, to understand its impact in target and non-target organisms and at different levels of biological organization by using several model organisms, including membranes of dipalmitoylphosphatidylcholine (DPPC), rat liver mitochondria, bacterial (Bacillus stearothermophilus), plant (Lemna gibba) and mammalian cell lines (HeLa and neuro2a). Our results demonstrated that alachlor strongly interacted with membranes of DPPC and interfered with mitochondrial bioenergetics by reducing the respiratory control ratio and the transmembrane potential. Moreover, alachlor also decreased the growth of B. stearothermophilus and its respiratory activity, as well as decreased the viability of both mammalian cell lines. The values of TC50 increased in the following order: Lemna gibba < neuro2a < HeLa cells < Bacillus stearothermophilus. Together, the results suggest that biological membranes constitute a putative target for the toxic action of this lipophilic herbicide and point out the risks of its dissemination on environment, compromising ecosystem equilibrium and human health.
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Affiliation(s)
- Susana P Pereira
- Department of Life Sciences, University of Coimbra, 3000-456 Coimbra, Portugal; CNC - Center for Neuroscience and Cell Biology, CIBB - Centre for Innovative Biomedicine and Biotechnology, University of Coimbra, IIIUC - Institute for Interdisciplinary Research, Coimbra, Portugal.
| | - Sandra M A Santos
- CNC - Center for Neuroscience and Cell Biology, CIBB - Centre for Innovative Biomedicine and Biotechnology, University of Coimbra, IIIUC - Institute for Interdisciplinary Research, Coimbra, Portugal.
| | | | - Cláudia M Deus
- CNC - Center for Neuroscience and Cell Biology, CIBB - Centre for Innovative Biomedicine and Biotechnology, University of Coimbra, IIIUC - Institute for Interdisciplinary Research, Coimbra, Portugal.
| | - João D Martins
- Department of Life Sciences, University of Coimbra, 3000-456 Coimbra, Portugal; CNC - Center for Neuroscience and Cell Biology, CIBB - Centre for Innovative Biomedicine and Biotechnology, University of Coimbra, IIIUC - Institute for Interdisciplinary Research, Coimbra, Portugal.
| | - Maria C Pedroso de Lima
- CNC - Center for Neuroscience and Cell Biology, CIBB - Centre for Innovative Biomedicine and Biotechnology, University of Coimbra, IIIUC - Institute for Interdisciplinary Research, Coimbra, Portugal.
| | | | - Romeu A Videira
- REQUIMTE/LAQV, Laboratory of Pharmacognosy, Department of Chemistry, Faculty of Pharmacy, University of Porto, 4050-313, Porto, Portugal.
| | - Amália S Jurado
- Department of Life Sciences, University of Coimbra, 3000-456 Coimbra, Portugal; CNC - Center for Neuroscience and Cell Biology, CIBB - Centre for Innovative Biomedicine and Biotechnology, University of Coimbra, IIIUC - Institute for Interdisciplinary Research, Coimbra, Portugal.
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Li H, Zhang R, Sun F, Zhang Y. Evaluation of toxicological responses and promising biomarkers of topmouth gudgeon (Pseudorasbora parva) exposed to fipronil at environmentally relevant levels. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2020; 27:24081-24089. [PMID: 32304060 DOI: 10.1007/s11356-020-08555-0] [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: 01/03/2020] [Accepted: 03/23/2020] [Indexed: 06/11/2023]
Abstract
Fipronil is an insecticide commonly used in agriculture. We report here on the sublethal and sub-chronic effects of fipronil on non-target topmouth gudgeon (Pseudorasbora parva) at environmentally relevant levels. The results showed that fipronil did not cause significant changes in brain acetylcholinesterase activities, glutathione S-transferase (GST) activities in the intestine, and GST, glutamic pyruvic transaminase (GPT), and glutamic oxaloacetic transaminase (GOT) activities in the liver tissues at environmentally relevant levels for 96-h exposure. In the further test for a 12-day exposure, dose-dependent responses of the serum GPT and GOT activities were observed in all treated groups with sublethal concentrations of fipronil. Furthermore, fipronil could reduce the liver mitochondrial membrane fluidity of P. parva, especially with high concentration of fipronil at high temperature. The results suggest that serum GPT and GOT in P. parva might be useful biomarkers for effects of fipronil exposure at environmentally relevant level, and reducing fluidity of liver mitochondrial membrane may be one toxic mechanism of fipronil.
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Affiliation(s)
- Huixian Li
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China.
| | - Ruiqing Zhang
- School of Ecology and Environment, Inner Mongolia University, Hohhot, 010021, Inner Mongolia, China
| | - Fuhong Sun
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China
| | - Yahui Zhang
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China.
- Environmental Analysis and Testing Laboratory of CRAES, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China.
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Du H, Wang M, Dai H, Hong W, Wang M, Wang J, Weng N, Nie Y, Xu A. Endosulfan isomers and sulfate metabolite induced reproductive toxicity in Caenorhabditis elegans involves genotoxic response genes. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2015; 49:2460-2468. [PMID: 25612189 DOI: 10.1021/es504837z] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Endosulfan is enlisted as one of the persistent organic pollutants (POPs) and exists in the form of its α and β isomers in the environment as well as in the form of endosulfan sulfate, a toxic metabolite. General endosulfan toxicity has been investigated in various organisms, but the effect of the isomers and sulfate metabolites on reproductive function is unclear. This study was aimed at studying the reproductive dysfunction induced by endosulfan isomers and its sulfate metabolite in Caenorhabditis elegans (C. elegans). We also determined a role for the DNA-damage-checkpoint gene hus-1. Compared to β-endosulfan and its sulfate metabolite, α-endosulfan caused a dramatically higher level of germ cell apoptosis, which was regulated by DNA damage signal pathway. Both endosulfan isomers and the sulfate metabolite induced germ cell cycle arrest. Loss-of-function studies using hus-1, egl-1, and cep-1 mutants revealed that hus-1 specifically influenced the fecundity, hatchability, and sexual ratio after endosulfan exposure. Our data provide clear evidence that the DNA-checkpoint gene hus-1 has an essential role in endosulfan-induced reproductive dysfunction and that α-endosulfan exhibited the highest reproductive toxicity among the different forms of endosulfan.
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Affiliation(s)
- Hua Du
- Key Laboratory of Ion Beam Bioengineering, Hefei Institutes of Physical Science, CAS and Anhui Province , Hefei, Anhui, PR China
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Vázquez JA, Rial D. Inhibition of selected bacterial growth by three hydrocarbons: mathematical evaluation of toxicity using a toxicodynamic equation. CHEMOSPHERE 2014; 112:56-61. [PMID: 25048888 DOI: 10.1016/j.chemosphere.2014.03.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2013] [Revised: 02/27/2014] [Accepted: 03/02/2014] [Indexed: 06/03/2023]
Abstract
The individual toxicity of different hydrocarbons (naphthalene, cyclododecane and aniline) on the growth of selected bacteria (Pseudomonas sp., Phaeobacter sp. and Leuconostoc mesenteroides) was studied by means of a toxicodynamic model combination of two sigmoid equations (logistic and Weibull). All the toxicological effects on growth parameters and kinetic properties were characterized and the global toxicity of such chemicals was evaluated. It was observed that two kinetic parameters (maximum growth and maximum growth rate) were in almost all cases influenced by the hydrocarbons studied. Aniline was less toxic than cyclododecane and naphthalene. The presented approach is a reasonable starting point for understanding and modeling complete and real assessment of chemical toxic effects on bacterial growths. The values of EC50,τ could be used for a most efficient comparison of the individual toxicity of chemicals.
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Affiliation(s)
- José A Vázquez
- Grupo de Reciclado e Valorización de Residuos (REVAL), Instituto de Investigacións Mariñas (IIM-CSIC), C/Eduardo Cabello 6, CP36208 Vigo, Spain.
| | - Diego Rial
- Grupo de Reciclado e Valorización de Residuos (REVAL), Instituto de Investigacións Mariñas (IIM-CSIC), C/Eduardo Cabello 6, CP36208 Vigo, Spain
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Toxicity of the herbicide linuron as assessed by bacterial and mitochondrial model systems. Toxicol In Vitro 2014; 28:932-9. [DOI: 10.1016/j.tiv.2014.04.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2013] [Revised: 03/19/2014] [Accepted: 04/01/2014] [Indexed: 11/18/2022]
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A biophysical approach to menadione membrane interactions: Relevance for menadione-induced mitochondria dysfunction and related deleterious/therapeutic effects. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2013; 1828:1899-908. [DOI: 10.1016/j.bbamem.2013.04.006] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2012] [Revised: 03/20/2013] [Accepted: 04/08/2013] [Indexed: 11/23/2022]
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Monteiro JP, Oliveira PJ, Jurado AS. Mitochondrial membrane lipid remodeling in pathophysiology: a new target for diet and therapeutic interventions. Prog Lipid Res 2013; 52:513-28. [PMID: 23827885 DOI: 10.1016/j.plipres.2013.06.002] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2013] [Revised: 06/14/2013] [Accepted: 06/17/2013] [Indexed: 12/22/2022]
Abstract
Mitochondria are arbiters in the fragile balance between cell life and death. These organelles present an intricate membrane system, with a peculiar lipid composition and displaying transverse as well as lateral asymmetry. Some lipids are synthesized inside mitochondria, while others have to be imported or acquired in the form of precursors. Here, we review different processes, including external interventions (e.g., diet) and a range of biological events (apoptosis, disease and aging), which may result in alterations of mitochondrial membrane lipid content. Cardiolipin, the mitochondria lipid trademark, whose biosynthetic pathway is highly regulated, will deserve special attention in this review. The modulation of mitochondrial membrane lipid composition, especially by diet, as a therapeutic strategy for the treatment of some pathologies will be also addressed.
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Affiliation(s)
- João P Monteiro
- CNC - Center for Neuroscience and Cell Biology, University of Coimbra, Portugal; Department of Life Sciences, University of Coimbra, Portugal
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Interaction of carbonylcyanide p-trifluoromethoxyphenylhydrazone (FCCP) with lipid membrane systems: a biophysical approach with relevance to mitochondrial uncoupling. J Bioenerg Biomembr 2011; 43:287-98. [DOI: 10.1007/s10863-011-9359-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2010] [Accepted: 04/24/2011] [Indexed: 10/18/2022]
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Song C, Gao HW, Wu LL. Transmembrane transport of microcystin to Danio rerio zygotes: insights into the developmental toxicity of environmental contaminants. Toxicol Sci 2011; 122:395-405. [PMID: 21602189 DOI: 10.1093/toxsci/kfr131] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Microcystins (MCs) produced by cyanobacteria and their continuing "blooms" are a worldwide problem owing to the toxicity of microcystin-LR (MC-LR) to plants and animals. In the present study, we investigated membrane transport of MC-LR and its toxic effects on zebrafish embryos using fragmentation of embryos, scanning electron microscope (SEM), fluorescence microscopy, and toxic exposure tests. At a concentration < 0.04 mmol/l, MC-LR was predominantly adsorbed on outer membrane surface of embryos according to Langmuir isotherm. The absorption characteristics of MC-LR within the range from 0.05 to 0.4 mmol/l conformed to Freundlich isotherm model. At concentrations > 0.50 mmol/l MC-LR directly entered the cytoplasm via partition. Thinning and disruption of membranes was confirmed using SEM and fluorescence morphological observations. Exposure to different concentrations of MC-LR resulted in differences in membrane transport and toxicity characteristics. At low concentrations, more than 75% of the adsorbed MC-LR accumulated on the outer membrane surface and resulted in axial malformation, tail curving, and tail twisting. Increasing the concentration of MC-LR to between 0.05 and 0.4 mmol/l improved membrane transport and it was evident in cytoplasm of embryos, resulting in serious pericardial edema, hatching gland edema, hemagglutination, hemorrhage, and vacuolization. At > 0.50 mmol/l, more than 70% of the adsorbed MC-LR entered the cytoplasm and this was lethal to the embryos. The current research outlines a new method and mechanism for the transmembrane transport of large molecular weight organic compounds and could be important for studies concerning molecular toxicology.
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Affiliation(s)
- Chao Song
- State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China
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Ren JR, Zhao HP, Song C, Wang SL, Li L, Xu YT, Gao HW. Comparative transmembrane transports of four typical lipophilic organic chemicals. BIORESOURCE TECHNOLOGY 2010; 101:8632-8638. [PMID: 20643544 DOI: 10.1016/j.biortech.2010.06.121] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2010] [Revised: 06/25/2010] [Accepted: 06/25/2010] [Indexed: 05/29/2023]
Abstract
Transmembrane transports of four kinds of lipophilic organic chemicals (LOCs) on suspending multilamellar liposomes (SML) and Escherichia coli (E. coli) were investigated, where both anthracene and phenanthrene were accorded to the lipid-water partition law and Sudan I and III to the Langmuir isothermal adsorption. Less than half of phenanthrene is transported into E. coli, where more than 60% are located in the cytoplasm. About 60% of anthracene entered the E. coli where only 10% was released into the cytoplasm. The partition coefficients of phenanthrene and anthracene partitioning from the extracellular liquid into membrane are 502 and 1190L/kg but their inverse partition coefficients are only 0.180 and 0.018kg/L. Over 60% of Sudan I and less than 40% of Sudan III accumulated on E. coli where most of them remained on the membrane. The transmembrane impedance effect (TMIE) is proposed for evaluating the cell-transport of polar LOCs.
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Affiliation(s)
- Jiao-Rong Ren
- State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai, China
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Pereira SP, Fernandes MAS, Martins JD, Santos MS, Moreno AJM, Vicente JAF, Videira RA, Jurado AS. Toxicity assessment of the herbicide metolachlor comparative effects on bacterial and mitochondrial model systems. Toxicol In Vitro 2009; 23:1585-90. [PMID: 19607910 DOI: 10.1016/j.tiv.2009.06.032] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2008] [Revised: 06/02/2009] [Accepted: 06/30/2009] [Indexed: 11/18/2022]
Abstract
Metolachlor is one of the most intensively used chloroacetamide herbicides. However, its effects on the environment and on non-target animals and humans as well as its interference at a cell/molecular level have not yet been fully elucidated. The aim of this study was: firstly, to evaluate the potential toxicity of metolachlor at a cell/subcellular level by using two in vitro biological model systems (a strain of Bacillus stearothermophilus and rat liver mitochondria); secondly, to evaluate the relative sensibility of these models to xenobiotics to reinforce their suitability for pollutant toxicity assessment. Our results show that metolachlor inhibits growth and impairs the respiratory activity of B.stearothermophilus at concentrations two to three orders of magnitude higher than those at which bacterial cells are affected by other pesticides. Also at concentrations significantly higher than those of other pesticides, metolachlor depressed the respiratory control ratio, membrane potential and respiration of rat liver mitochondria when malate/glutamate or succinate were used as respiratory substrates. Moreover, metolachlor impaired the respiratory activity of rat liver mitochondria in the same concentration range at which it inhibited bacterial respiratory system (0.4-5.0 micromol/mg of protein). In conclusion, the high concentration range at which metolachlor induces toxicity in vitro suggests that this compound is safer than other pesticides previously studied in our laboratory, using the same model systems. The good parallelism between metolachlor effects on both models and the toxicity data described in the literature, together with results obtained in our laboratory with other compounds, indicate the suitability of these systems to assess toxicity in vitro.
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Affiliation(s)
- Susana P Pereira
- CNC - Centre for Neuroscience and Cell Biology, Zoology Department, Coimbra University, Portugal
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Monteiro JP, Oliveira PJ, Moreno AJM, Jurado AS. Disruption of hepatic mitochondrial bioenergetics is not a primary mechanism for the toxicity of methoprene - relevance for toxicological assessment. CHEMOSPHERE 2008; 72:1347-1354. [PMID: 18511104 DOI: 10.1016/j.chemosphere.2008.04.024] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2007] [Revised: 03/28/2008] [Accepted: 04/10/2008] [Indexed: 05/26/2023]
Abstract
Methoprene (isopropyl(2E,4E)-11-methoxy-3,7,11-trimethyl-2,4-dodecadienoate) is an insect growth regulator generally used to control insect populations by preventing insect maturation. So far, the effects of the insecticide on mitochondrial bioenergetics were not investigated. In the present work, liver mitochondria from Wistar rats were isolated and features of mitochondrial physiology were characterized in the presence of methoprene. High concentrations of methoprene, in the range of 40-100 nmol/mg of protein could decrease the transmembrane electric potential (Delta Psi) developed by mitochondria and, at the highest concentration, methoprene prevented complete Delta Psi repolarization after ADP addition. The effect was more evident using succinate than with ascorbate+TMPD as substrate. State 3 respiration was approximately 60% inhibited by 80 nmol of methoprene/mg of protein, while state 4 respiration, within the same range of methoprene concentrations, showed a slight increase, when both glutamate-malate and succinate were used as substrates. Additionally, FCCP-stimulated respiration was inhibited to an extent comparable to the effect on state 3, which suggests an interaction of methoprene with the respiratory chain, more evident with glutamate/malate as substrate. The activity of complex I (NADH-ubiquinone oxidorreductase) and that of the segment comprehending complexes II and III (succinate-cytochrome c reductase) were decreased in the presence of methoprene (approximately 60% and 85% of inhibition, respectively, with 300 nmol of methoprene/mg of protein), while the activities of cytochrome c oxidase and ATPase do not seem to be affected. Furthermore, the action of methoprene on the mitochondrial permeability transition was also studied, showing that the insecticide (in the range of 30-80 nmol mg(-1) of protein) decreases the susceptibility of liver mitochondria to the opening of the transition pore, even in non-energized mitochondria. These results lead to the conclusion that methoprene interference with hepatic mitochondrial function occurs only for high concentrations, which implies that the noxious effects of the insecticide reported for a number of non-target organisms are not fully attributable to mitochondrial effects. Therefore, it seems that mitochondrial activity does not represent the primary target for methoprene toxic action.
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Affiliation(s)
- J P Monteiro
- Centro de Neurociências e Biologia Celular, Department of Zoology, University of Coimbra, Coimbra, Portugal
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Monteiro JP, Videira RA, Matos MJ, Dinis AM, Jurado AS. Non-Selective Toxicological Effects of the Insect Juvenile Hormone Analogue Methoprene. A Membrane Biophysical Approach. Appl Biochem Biotechnol 2008; 150:243-57. [DOI: 10.1007/s12010-007-8127-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2007] [Accepted: 12/07/2007] [Indexed: 11/28/2022]
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Martins JD, Jurado AS, Moreno AJM, Madeira VMC. Comparative study of tributyltin toxicity on two bacteria of the genus Bacillus. Toxicol In Vitro 2005; 19:943-9. [PMID: 16061343 DOI: 10.1016/j.tiv.2005.06.019] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2005] [Accepted: 06/17/2005] [Indexed: 11/30/2022]
Abstract
Tributyltin is a potent biocide mainly used in marine anti-fouling paints. Owing to its widespread distribution in coast areas and its high toxicity to aquatic organisms, the use of this compound is generally restricted and under government regulation. Despite of that, it persists in the aquatic environment. Organotins used in industry have also been detected in terrestrial environments. The persistence and high lipophilicity explain bioaccumulation. The role of bacteria in recycling organic matter prompted us to study the interaction of tributyltin with two ubiquitous bacilli, B. stearothermophilus and B. subtilis, proposed as biological indicators of pollutants with ecological impact. These bacteria have been used as suitable models for the study of toxicity mechanisms of unselective lipophilic compounds (e.g., DDT and endosulfan). Drug effects on growth parameters, oxygen consumption and membrane organization were assessed. Bacteria growth in a liquid complex medium was disturbed by concentrations of TBT as low as 25 nM (8 microgL(-1)), close to the concentration in polluted environments. The respiratory activity is affected by TBT in both microorganisms. Membrane organization, assessed by fluorescence polarization of two fluidity probes, 1,6-diphenyl-1,3,5-hexatriene (DPH) and a propionic acid derivative (DPH-PA), was also perturbed by the xenobiotic. Alterations on growth, oxygen consumption and physical properties of membrane lipids are stronger in B. stearothermophilus as compared to B. subtilis. A putative relationship between growth inhibition and respiratory activity impairment induced by TBT and its effects on the physical behaviour of bacterial membrane lipids is suggested.
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Affiliation(s)
- J D Martins
- Centro de Neurociências, Departamento de Zoologia, Universidade de Coimbra, 3000 Coimbra, Portugal
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Monteiro JP, Jurado AS, Moreno AJM, Madeira VMC. Toxicity of methoprene as assessed by the use of a model microorganism. Toxicol In Vitro 2005; 19:951-6. [PMID: 16081242 DOI: 10.1016/j.tiv.2005.06.020] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2005] [Accepted: 06/17/2005] [Indexed: 10/25/2022]
Abstract
Methoprene is an insect juvenile growth hormone mimic, commonly used as a pesticide. Although widely used for the control of several pests, toxic effects on organisms of different phyla have been reported. These events triggered studies to clarify the mechanisms of toxicity of this insecticide putatively involved in ecological issues. Here we show the effect of methoprene on the normal cell growth and viability of a strain of the thermophilic eubacterium Bacillus stearothermophilus, previously used as a model for toxicological evaluation of other environment pollutants. Respiration studies were also carried out attempting to identify a putative target for the cytotoxic action of methoprene. Cell growth was affected and a decrease of the number of viable cells was observed as a result of the addition of methoprene to the growth medium, an effect reverted by the presence of Ca(2+). Methoprene also inhibited the redox flow of B. stearothermophilus protoplasts before the cytochrome oxidase segment, an effect further studied by individually assessing the enzymatic activities of the respiratory complexes. This study suggests that methoprene membrane interaction and perturbation of cell bioenergetics may underlie the mechanism of toxicity of this compound in non-target organisms.
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Affiliation(s)
- J P Monteiro
- Centro de Neurociências, Departamento de Zoologia, Universidade de Coimbra, 3004-517 Coimbra, Portugal
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