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de Melo MS, Das K, Gismondi E. Inorganic mercury effects on biomarker gene expressions of a freshwater amphipod at two temperatures. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2021; 209:111815. [PMID: 33387774 DOI: 10.1016/j.ecoenv.2020.111815] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Revised: 12/08/2020] [Accepted: 12/14/2020] [Indexed: 06/12/2023]
Abstract
Mercury (Hg) is a global contaminant resulting of both natural processes and human activities. In aquatic environments, studies conducted on vertebrates highlighted changes of gene expression or activity of antitoxic and oxidative enzymes. However, although Hg is a highly toxic compound in aquatic environments, only a few studies have evaluated the lethal and sublethal effects of inorganic Hg on Gammarus sp. Therefore, this study aimed at evaluating the effects of inorganic Hg (HgCl2) on the expression of 17 genes involved in crucial biological functions or mechanisms for organisms, namely respiration, osmoregulation, apoptosis, immune and endocrine system, and antioxidative and antitoxic defence systems. The study was performed in males of the freshwater amphipod Gammarus pulex exposed to two environmentally relevant concentrations (50 and 500 ng/L) at two temperature regime fluctuations (16 °C and 20 °C +/-2 °C) for 7 and 21 days. Results showed that G. pulex mortality was dependent on Hg concentration and temperature; the higher the concentration and temperature, the higher the mortality rate. In addition, the Integrated Biomarker Response emphasized that HgCl2 toxicity was dependent on the concentration, time and temperature of exposure. Overall, antioxidant and antitoxic defences, as well as the endocrine and immune systems, were the biological functions most impacted by Hg exposure (based on the concentration, duration, and temperature tested). Conversely, osmoregulation was the least affected biological function. The results also demonstrated a possible adaptation of G. pulex after 21 days at 500 ng/L, regardless of the exposure temperature. This study allowed us to show that Hg deregulates many crucial biological functions after a short exposure, but that during a long exposure, an adaptation phenomenon could occur, regardless of temperature.
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Affiliation(s)
- Madson Silveira de Melo
- Laboratório de Reprodução e Desenvolvimento Animal, Departamento de Biologia Celular, Embriologia e Genética, Universidade Federal de Santa Catarina, Florianópolis, Santa Catarina, Brazil; Laboratory of Animal Ecology and Ecotoxicology (LEAE), Freshwater and Oceanic Sciences Unit of ReSearch (FOCUS), University of Liège B6c, 11 allée du 6 Août, 4000, Liège, Belgium
| | - Krishna Das
- Laboratory of Oceanology, Freshwater and Oceanic Sciences Unit of ReSearch (FOCUS), University of Liège B6c, 11 Allée du 6 Août, 4000 Liège, Belgium
| | - Eric Gismondi
- Laboratory of Animal Ecology and Ecotoxicology (LEAE), Freshwater and Oceanic Sciences Unit of ReSearch (FOCUS), University of Liège B6c, 11 allée du 6 Août, 4000, Liège, Belgium.
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Ajsuvakova OP, Tinkov AA, Aschner M, Rocha JB, Michalke B, Skalnaya MG, Skalny AV, Butnariu M, Dadar M, Sarac I, Aaseth J, Bjørklund G. Sulfhydryl groups as targets of mercury toxicity. Coord Chem Rev 2020; 417:213343. [PMID: 32905350 PMCID: PMC7470069 DOI: 10.1016/j.ccr.2020.213343] [Citation(s) in RCA: 142] [Impact Index Per Article: 35.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The present study addresses existing data on the affinity and conjugation of sulfhydryl (thiol; -SH) groups of low- and high-molecular-weight biological ligands with mercury (Hg). The consequences of these interactions with special emphasis on pathways of Hg toxicity are highlighted. Cysteine (Cys) is considered the primary target of Hg, and link its sensitivity with thiol groups and cellular damage. In vivo, Hg complexes play a key role in Hg metabolism. Due to the increased affinity of Hg to SH groups in Cys residues, glutathione (GSH) is reactive. The geometry of Hg(II) glutathionates is less understood than that with Cys. Both Cys and GSH Hg-conjugates are important in Hg transport. The binding of Hg to Cys mediates multiple toxic effects of Hg, especially inhibitory effects on enzymes and other proteins that contain free Cys residues. In blood plasma, albumin is the main Hg-binding (Hg2+, CH3Hg+, C2H5Hg+, C6H5Hg+) protein. At the Cys34 residue, Hg2+ binds to albumin, whereas other metals likely are bound at the N-terminal site and multi-metal binding sites. In addition to albumin, Hg binds to multiple Cys-containing enzymes (including manganese-superoxide dismutase (Mn-SOD), arginase I, sorbitol dehydrogenase, and δ-aminolevulinate dehydratase, etc.) involved in multiple processes. The affinity of Hg for thiol groups may also underlie the pathways of Hg toxicity. In particular, Hg-SH may contribute to apoptosis modulation by interfering with Akt/CREB, Keap1/Nrf2, NF-κB, and mitochondrial pathways. Mercury-induced oxidative stress may ensue from Cys-Hg binding and inhibition of Mn-SOD (Cys196), thioredoxin reductase (TrxR) (Cys497) activity, as well as limiting GSH (GS-HgCH3) and Trx (Cys32, 35, 62, 65, 73) availability. Moreover, Hg-thiol interaction also is crucial in the neurotoxicity of Hg by modulating the cytoskeleton and neuronal receptors, to name a few. However, existing data on the role of Hg-SH binding in the Hg toxicity remains poorly defined. Therefore, more research is needed to understand better the role of Hg-thiol binding in the molecular pathways of Hg toxicology and the critical role of thiols to counteract negative effects of Hg overload.
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Affiliation(s)
- Olga P. Ajsuvakova
- Yaroslavl State University, Yaroslavl, Russia
- Federal Scientific Center of Biological Systems and Agrotechnologies of the Russian Academy of Sciences, Orenburg, Russia
- IM Sechenov First Moscow State Medical University, Moscow, Russia
| | - Alexey A. Tinkov
- Yaroslavl State University, Yaroslavl, Russia
- Federal Scientific Center of Biological Systems and Agrotechnologies of the Russian Academy of Sciences, Orenburg, Russia
- IM Sechenov First Moscow State Medical University, Moscow, Russia
| | - Michael Aschner
- IM Sechenov First Moscow State Medical University, Moscow, Russia
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY, USA
| | - João B.T. Rocha
- Departamento de Bioquímica e Biologia Molecular, CCNE, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil
| | | | | | - Anatoly V. Skalny
- Yaroslavl State University, Yaroslavl, Russia
- Federal Scientific Center of Biological Systems and Agrotechnologies of the Russian Academy of Sciences, Orenburg, Russia
- IM Sechenov First Moscow State Medical University, Moscow, Russia
| | - Monica Butnariu
- Banat’s University of Agricultural Sciences and Veterinary Medicine “King Michael I of Romania” from Timișoara, Timişoara, Romania
- CONEM Romania Biotechnology and Environmental Sciences Group, Banat’s University of Agricultural Sciences and Veterinary Medicine “King Michael I of Romania” from Timișoara, Timişoara, Romania
| | - Maryam Dadar
- Razi Vaccine and Serum Research Institute, Agricultural Research, Education and Extension Organization (AREEO), Karaj, Iran
| | - Ioan Sarac
- Banat’s University of Agricultural Sciences and Veterinary Medicine “King Michael I of Romania” from Timișoara, Timişoara, Romania
- CONEM Romania Biotechnology and Environmental Sciences Group, Banat’s University of Agricultural Sciences and Veterinary Medicine “King Michael I of Romania” from Timișoara, Timişoara, Romania
| | - Jan Aaseth
- IM Sechenov First Moscow State Medical University, Moscow, Russia
- Research Department, Innlandet Hospital Trust, Brumunddal, Norway
| | - Geir Bjørklund
- Council for Nutritional and Environmental Medicine (CONEM), Mo i Rana, Norway
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Metal Species in Biology: Bottom-Up and Top-Down LC Approaches in Applied Toxicological Research. ACTA ACUST UNITED AC 2013. [DOI: 10.1155/2013/801840] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Since the inception of liquid chromatography (LC) more than 100 years ago this separation technique has been developed into a powerful analytical tool that is frequently applied in life science research. To this end, unique insights into the interaction of metal species (throughout this manuscript “metal species” refers to “toxic metals, metalloid compounds, and metal-based drugs” and “toxic metals” to “toxic metals and metalloid compounds”) with endogenous ligands can be obtained by using LC approaches that involve their hyphenation with inductively coupled plasma-based element specific detectors. This review aims to provide a synopsis of the different LC approaches which may be employed to advance our understanding of these interactions either in a “bottom-up” or a “top-down” manner. In the “bottom-up” LC-configuration, endogenous ligands are introduced into a physiologically relevant mobile phase buffer, and the metal species of interest is injected. Subsequent “interrogation” of the on-column formed complex(es) by employing a suitable separation mechanism (e.g., size exclusion chromatography or reversed-phase LC) while changing the ligand concentration(s), the column temperature or the pH can provide valuable insight into the formation of complexes under near physiological conditions. This approach allows to establish the relative stability and hydrophobicity of metal-ligand complexes as well as the dynamic coordination of a metal species (injected) to two ligands (dissolved in the mobile phase). Conversely, the “top-down” analysis of a biological fluid (e.g., blood plasma) by LC (e.g., using size exclusion chromatography) can be used to determine the size distribution of endogenous metalloproteins which are collectively referred to as the “metalloproteome”. This approach can provide unique insight into the metabolism and the plasma protein binding of metal species, and can simultaneously visualize the dose-dependent perturbation of the metalloproteome by a particular metal species. The concerted application of these LC approaches is destined to provide new insight into biochemical processes which represent an important starting point to advance human health in the 21st century.
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Shettihalli AK, Gummadi SN. Biochemical evidence for lead and mercury induced transbilayer movement of phospholipids mediated by human phospholipid scramblase 1. Chem Res Toxicol 2013; 26:918-25. [PMID: 23659204 DOI: 10.1021/tx400090h] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Human phospholipid scramblase 1(hPLSCR1) is a transmembrane protein involved in bidirectional scrambling of plasma membrane phospholipids during cell activation, blood coagulation, and apoptosis in response to elevated intracellular Ca(2+) levels. Pb(2+) and Hg(2+) are known to cause procoagulant activation via phosphatidylserine exposure to the external surface in erythrocytes, resulting in blood coagulation. To explore its role in lead and mercury poisoning, hPLSCR1 was overexpressed in Escherichia coli BL21 (DE3) and purified using affinity chromatography. The biochemical assay showed rapid scrambling of phospholipids in the presence of Hg(2+) and Pb(2+). The binding constant (Ka) was calculated and found to be 250 nM(-1) and 170 nM(-1) for Hg(2+) and Pb(2+), respectively. The intrinsic tryptophan fluorescence and far ultraviolet circular dichroism studies revealed that Hg(2+) and Pb(2+) bind to hPLSCR1 and induce conformational changes. hPLSCR1 treated with protein modifying reagent N-ethylmaleimide before functional reconstitution showed 40% and 24% inhibition in the presence of Hg(2+) and Pb(2+), respectively. This is the first biochemical evidence to prove the above hypothesis that hPLSCR1 is activated in heavy metal poisoning, which leads to bidirectional transbilayer movement of phospholipids.
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Affiliation(s)
- Ashok Kumar Shettihalli
- Applied and Industrial Microbiology Laboratory, Department of Biotechnology, Indian Institute of Technology Madras, Chennai 600 036, India
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Mercury toxicity on sodium pump and organoseleniums intervention: a paradox. J Biomed Biotechnol 2012; 2012:924549. [PMID: 22927724 PMCID: PMC3425867 DOI: 10.1155/2012/924549] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2012] [Accepted: 07/01/2012] [Indexed: 12/21/2022] Open
Abstract
Mercury is an environmental poison, and the damage to living system is generally severe. The severity of mercury poisoning is consequent from the fact that it targets the thiol-containing enzymes, irreversibly oxidizing their critical thiol groups, consequently leading to an inactivation of the enzyme. The Na+/K+-ATPase is a sulfhydryl protein that is sensitive to Hg2+ assault. On the other hand, organoseleniums are a class of pharmacologically promising compounds with potent antioxidant effects. While Hg2+ oxidizes sulfhydryl groups of Na+/K+-ATPase under in vitro and in vivo conditions, the organoselenium compounds inhibit Na+/K+-ATPase in vitro but enhance its activities under in vivo conditions with concomitant increase in the level of endogenous thiols. Paradoxically, it appears that these two thiol oxidants can be used to counteract one another under in vivo conditions, and this hypothesis serves as the basis for this paper.
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Exposure to low dose of cinnabar (a naturally occurring mercuric sulfide (HgS)) caused neurotoxicological effects in offspring mice. J Biomed Biotechnol 2012; 2012:254582. [PMID: 22888198 PMCID: PMC3408718 DOI: 10.1155/2012/254582] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2012] [Accepted: 05/24/2012] [Indexed: 11/17/2022] Open
Abstract
Cinnabar, a naturally occurring mercuric sulfide (HgS), has long been used in Chinese mineral medicine for more than 2000 years. Although mercury is well-known for its toxicity, whether cinnabar induces neurotoxicity, especially in infants and children, is unknown. The purpose of this study was to explore the neurotoxic effects of low-dose of cinnabar (10 mg/kg/day) on developing mice. The results revealed neurobehavioral defects in F1-C-Cin group, which were associated with Hg accumulation, increased NO(x) levels in whole blood, and Na(+)/K(+)-ATPase activities in brain tissues. F1- and F2-Cin-V groups were found to increase brain Hg contents and prominent neurobehavioral defects compared with F1-C-V group, suggesting that the fetal brain was more susceptible to irreversible effects for cinnabar-induced damage. Moreover, F1- and F2-Cin-Cin groups had severely neurobehavioral dysfunctions, closely correlated with the further alteration of NO(x) levels and Na(+)/K(+)-ATPase activities than F1- and F2-C-Cin groups. Effects in F2-Cin-Cin group were more significant than those in F1-Cin-Cin group. In conclusion, this study demonstrates that exposure to low-dose of cinnabar during the perinatal and developmental stages results in irreversible and severe injuries of the neurotoxicity in offspring, and NO(x) and Na(+)/K(+)-ATPase activities may exist potential and useful biomarkers for neurotoxicity-induced by low-doses of mercuric compounds.
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Stacchiotti A, Li Volti G, Lavazza A, Rezzani R, Rodella LF. Schisandrin B stimulates a cytoprotective response in rat liver exposed to mercuric chloride. Food Chem Toxicol 2009; 47:2834-40. [DOI: 10.1016/j.fct.2009.09.003] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2009] [Revised: 08/21/2009] [Accepted: 09/03/2009] [Indexed: 11/29/2022]
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Heggland I, Kaur P, Syversen T. Uptake and efflux of methylmercury in vitro: Comparison of transport mechanisms in C6, B35 and RBE4 cells. Toxicol In Vitro 2009; 23:1020-7. [DOI: 10.1016/j.tiv.2009.06.018] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2009] [Revised: 06/10/2009] [Accepted: 06/15/2009] [Indexed: 10/20/2022]
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9
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Chapleau RR, Sagermann M. Real-time in vivo imaging of mercury uptake in Caenorhabditis elegans through the foodchain. Toxicology 2009; 261:136-42. [DOI: 10.1016/j.tox.2009.05.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2009] [Revised: 05/08/2009] [Accepted: 05/11/2009] [Indexed: 12/16/2022]
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Na⁺,K⁺-ATPase as the Target Enzyme for Organic and Inorganic Compounds. SENSORS 2008; 8:8321-8360. [PMID: 27873990 PMCID: PMC3791021 DOI: 10.3390/s8128321] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/03/2008] [Revised: 11/09/2008] [Accepted: 12/11/2008] [Indexed: 01/16/2023]
Abstract
This paper gives an overview of the literature data concerning specific and non specific inhibitors of Na+,K+-ATPase receptor. The immobilization approaches developed to improve the rather low time and temperature stability of Na+,K+-ATPase, as well to preserve the enzyme properties were overviewed. The functional immobilization of Na+,K+-ATPase receptor as the target, with preservation of the full functional protein activity and access of various substances to an optimum number of binding sites under controlled conditions in the combination with high sensitive technology for the detection of enzyme activity is the basis for application of this enzyme in medical, pharmaceutical and environmental research.
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Ototoxicity induced by cinnabar (a naturally occurring HgS) in mice through oxidative stress and down-regulated Na+/K+-ATPase activities. Neurotoxicology 2008; 29:386-96. [DOI: 10.1016/j.neuro.2008.01.005] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2007] [Revised: 01/11/2008] [Accepted: 01/25/2008] [Indexed: 11/22/2022]
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12
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Reus IS, Bando I, Andrés D, Cascales M. Relationship between expression of HSP70 and metallothionein and oxidative stress during mercury chloride induced acute liver injury in rats. J Biochem Mol Toxicol 2004; 17:161-8. [PMID: 12815612 DOI: 10.1002/jbt.10074] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Mercury is a highly toxic metal which induces oxidative stress. Metallothionein and heat shock protein 70 (HSP70) are stress proteins involved in response to different stimuli. In the present study rats were administered per oral application by gavage, a single daily dose (0.1 mg/kg) of HgCl(2) for 3 consecutive days. To find a relation between these two stress proteins and mercury, parameters of liver injury, redox state of the cells, and the expression and protein levels of HSP70 and metallothionein by Northern and Western blot analysis were assayed either in blood or in liver. HgCl(2) at the doses of 0.1 mg/kg induced liver injury detected by a slight increase in serum aspartate aminotransferase and alkaline phosphatase activities and by the enhanced levels of bilirubin. Oxidative stress was detected by a significant decrease in protein-SH and an increase in thiobarbituric acid reactive substances in liver following one dose of mercury. mRNA and protein levels of both metallothionein and HSP70 increased progressively from first to third doses of mercury. We conclude that against low doses of mercury that produce a slight liver injury and oxidative stress, the liver rapidly responds by inducing the expression of metallothionein and HSP70. We suggest that metallothionein induction attenuates the decrease in protein-SH induced by the first dose of mercury, since metallothionein increases the pool of thiol groups in the cytosol eliminating oxygen radicals and inhibiting lipid peroxidation. From these results we can suggest that the changes observed in these stress proteins by the effect of mercury appear to be a response rapidly induced at transcriptional and at translational levels.
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Affiliation(s)
- Isabel Sánchez Reus
- Instituto de Bioquímica (CSIC-UCM), Facultad de Farmacia, Universidad Complutense, Plaza de Ramón y Cajal sn, 28040 Madrid, Spain
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Vasić V, Jovanović D, Horvat A, Momić T, Nikezić G. Effect of Cd(2+) and Hg(2+) on the activity of Na(+)/K(+)-ATPase and Mg(2+)-ATPase adsorbed on polystyrene microtiter plates. Anal Biochem 2002; 300:113-20. [PMID: 11779101 DOI: 10.1006/abio.2001.5405] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In the present study a polystyrene microtiter plate was tested as a support material for synaptic plasma membrane (SPM) immobilization by adsorption. The adsorption was carried out by an 18-h incubation at +4 degrees C of SPM with a polystyrene matrix, at pH 7.4. Evaluation of the efficiency of the applied immobilization method revealed that 10% protein fraction of initially applied SPM was bound to the support and that two SPM enzymes, Na(+)/K(+)-ATPase and Mg(2+)-ATPase, retained 70-80% activity after the adsorption. In addition, adsorption stabilizes Na(+)/K(+)-ATPase and Mg(2+)-ATPase, since the activities are substantial 3 weeks after the adsorption. Parallel kinetic analysis showed that adsorption does not alter significantly the kinetic properties of Na(+)/K(+)-ATPase and Mg(2+)-ATPase and their sensitivity to and mechanism of Cd(2+)- or Hg(2+)-induced inhibition. The only exception is the "high affinity" Mg(2+)-ATPase moiety, whose affinity for ATP and sensitivity toward Cd(2+) were increased by the adsorption. The results show that such system may be used as a practical and comfortable model for the in vitro toxicological investigations.
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Affiliation(s)
- Vesna Vasić
- Department of Physical Chemistry, Vinca Institute of Nuclear Sciences, 11001 Belgrade, Yugoslavia.
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Zierold K. Heavy metal cytotoxicity studied by electron probe X-ray microanalysis of cultured rat hepatocytes. Toxicol In Vitro 2000; 14:557-63. [PMID: 11033068 DOI: 10.1016/s0887-2333(00)00049-7] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Cytotoxicity of the heavy metals gold, mercury, thallium and lead was studied by measuring the intracellular element distribution of cultured rat hepatocytes by energy dispersive electron probe X-ray microanalysis of freeze-dried cryosections in a scanning transmission electron microscope. Exposure of the cells to aqueous solutions containing heavy metal ions in concentrations reaching a critical concentration caused increase of intracellular sodium and chloride content accompanied or followed by decrease of intracellular potassium content. Thus, the intracellular potassium/sodium ratio drastically decreased from control values of approximately 10 to values below 1 before changes of cell morphology became visible. In experiments with gold or mercury the decrease of the potassium/sodium ratio was preceded by transient cytoplasmic increase of sulfur and phosphorus. Heavy metal concentrations exceeding the critical concentration also caused an increase of cytoplasmic calcium concentration and finally decay of the cell structure. Cytotoxicity of heavy metals was found to increase in the order Pb, Au, Tl, Hg. Cytotoxic effects by Au, Tl or Hg in moderate concentrations were reduced by simultaneous addition of Zn or Pb to the culture medium. The results obtained prove electron probe X-ray microanalysis of cryosections as a sensitive probe of cell viability.
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Affiliation(s)
- K Zierold
- Max-Planck-Institut für molekulare Physiologie, Otto-Hahn-Str. 11, 44227, Dortmund, Germany.
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Lapina VA, Sheshko PM, Pankovets EA, Dontsov AE. Phytosorbent prepared from sunflower seed husks prevents mercuric chloride accumulation in kidney and muscle of adult rabbits. ARCHIVES OF ENVIRONMENTAL HEALTH 2000; 55:48-50. [PMID: 10735520 DOI: 10.1080/00039890009603385] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
In the present study, the effect of a melanin-containing phytosorbent, "Victoria," on mercury accumulation in rabbits' tissues was studied. This phytosorbent is derived from black sunflower seed husks. Domestic rabbits were administered either one single nontoxic low-level dose of mercuric chloride (i.e., 50 microg/1 kg body weight [control group]) or combinations of mercury and the phytosorbent "Victoria" (i.e., experimental group). Mercury and phytosorbent were administered per os daily for 12 d. Mercury in tissues was determined by cold-vapor atomic absorption spectroscopy. Mercury in kidney and muscle of the experiment group was, on average, 25.8 and 4.7 times less, respectively, than in the control group. The authors concluded that the phytosorbent prevented accumulation of mercury in the kidney and muscle tissues and exerted a protective effect against mercury toxicity.
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Affiliation(s)
- V A Lapina
- Institute of Physics, National Academy of Sciences of Belarus, Minsk
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Bhattacharya S. Mechanisms of signal transduction in the stress response of hepatocytes. INTERNATIONAL REVIEW OF CYTOLOGY 1998; 184:109-56. [PMID: 9697312 DOI: 10.1016/s0074-7696(08)62180-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Adaptation of animals to stress is a unique property of life which allows the survival of the species. The stress response of hepatocytes is a very complex phenomenon, sometimes involving a cascade of events. The general stress signals are elucidated by mobilization of carbohydrate stores and akin to the insulin mediators. Oxidative signals are generated by pesticides, heavy metals, drugs, and alcohol which may or may not be under the purview of peroxisomes. Peroxisomal responses are well-defined involving specific receptors, whereas nonperoxisomal responses may be signaled by calcium, the Ah receptor, or built-in antioxidant systems. The intoxication signals are generally thought to be membrane defects induced by xenobiotics which then lead to highly nonspecific responses of hepatocytes. Detoxication signals, on the other hand, are specific responses of hepatocytes triggering de novo syntheses of detoxifier proteins or enzymes. Evidence reveals the existence of two distinct mechanisms of signal transduction in stressed hepatocytes--one involving the peroxisome and the other the plasma membrane.
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Affiliation(s)
- S Bhattacharya
- Department of Zoology, Visva Bharati University, Santiniketan, India
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