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Hauser-Davis RA, Bastos FF, Dantas RF, Tobar SAL, da Cunha Bastos Neto J, da Cunha Bastos VLF, Ziolli RL, Arruda MAZ. Behaviour of the oxidant scavenger metallothionein in hypoxia-induced neotropical fish. Ecotoxicol Environ Saf 2014; 103:24-28. [PMID: 24561243 DOI: 10.1016/j.ecoenv.2014.01.015] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2013] [Revised: 01/09/2014] [Accepted: 01/10/2014] [Indexed: 06/03/2023]
Abstract
The pacu (Piaractus mesopotamicus) is a hypoxia-tolerant neotropical fish species. There is little or no information in this species regarding biochemical adaptations to waters with different oxygen concentrations, such as the production of reactive oxygen species and antioxidant scavengers, which might be of interest in the study of antioxidant defense mechanisms. Metallothioneins (MT) have been widely applied as biomarkers for metal exposure in fish liver, and, recently, in bile. These metalloproteins, however, have also been reported as free radical scavengers, although studies in this regard are scarce in fish. In this context, normoxic and hypoxic controlled experiments were conducted with pacu specimens and MT levels were quantified in both liver and bile. Reduced glutathione (GSH) indicative of oxidative stress, and thiobarbituric acid reactive substances (TBARS), indicative of lipid peroxidation, were also determined in liver. The results demonstrate that hypoxic fish present significantly lower metallothionein levels in liver and bile and lower reduced glutathione levels in liver, whereas lipid peroxidation was not significantly different between hypoxic and normoxic fish. The results of the present study seem to suggest that metallothioneins may actively participate in redox regulation in hypoxic fish in both bile and liver. MT levels in these organs may be temporarily suppressed, supporting the notion that down-regulation of oxidant scavengers during the oxidative burst is important in defense signaling in these adapted organisms.
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Affiliation(s)
- Rachel Ann Hauser-Davis
- Instituto de Química/UNICAMP, Grupo de Espectrometria, Preparo de amostras e Mecanização-GEPAM, C. Postal 6154, 13084-971 Campinas, SP, Brazil; National Institute of Science and Technology for Bioanalitics, Instituto de Química/UNICAMP, Grupo de Espectrometria, Preparo de amostras e Mecanização-GEPAM, C. Postal 6154, 13084-971 Campinas, SP, Brazil.
| | - Frederico Freire Bastos
- UERJ, Instituto de Biologia Roberto Alcântara Gomes, Departamento de Bioquímica, Av. Manoel de Abreu 444, Maracanã, CEP 20550-900, Rio de Janeiro, RJ, Brazil
| | - Rafael Ferreira Dantas
- UERJ, Instituto de Biologia Roberto Alcântara Gomes, Departamento de Bioquímica, Av. Manoel de Abreu 444, Maracanã, CEP 20550-900, Rio de Janeiro, RJ, Brazil; Fundação Oswaldo Cruz, Instituto Oswaldo Cruz, Laboratório de Bioquímica de Proteínas e Peptídeos, 21040-360 Rio de Janeiro, RJ, Brazil
| | - Santiago Alonso Leitão Tobar
- UERJ, Instituto de Biologia Roberto Alcântara Gomes, Departamento de Bioquímica, Av. Manoel de Abreu 444, Maracanã, CEP 20550-900, Rio de Janeiro, RJ, Brazil
| | - Jayme da Cunha Bastos Neto
- UERJ, Instituto de Biologia Roberto Alcântara Gomes, Departamento de Bioquímica, Av. Manoel de Abreu 444, Maracanã, CEP 20550-900, Rio de Janeiro, RJ, Brazil
| | - Vera Lucia Freire da Cunha Bastos
- National Institute of Science and Technology for Bioanalitics, Instituto de Química/UNICAMP, Grupo de Espectrometria, Preparo de amostras e Mecanização-GEPAM, C. Postal 6154, 13084-971 Campinas, SP, Brazil
| | - Roberta Lourenço Ziolli
- Programa de Pós-Graduação em Biodiversidade Neotropical, Universidade Federal do Estado do Rio de Janeiro-UNIRIO, Av. Pasteur, 458 Urca, CEP 22290-240, Rio de Janeiro RJ, Brazil
| | - Marco Aurélio Zezzi Arruda
- Instituto de Química/UNICAMP, Grupo de Espectrometria, Preparo de amostras e Mecanização-GEPAM, C. Postal 6154, 13084-971 Campinas, SP, Brazil; National Institute of Science and Technology for Bioanalitics, Instituto de Química/UNICAMP, Grupo de Espectrometria, Preparo de amostras e Mecanização-GEPAM, C. Postal 6154, 13084-971 Campinas, SP, Brazil
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Bastos FF, Tobar SAL, Dantas RF, Silva ES, Nogueira NPA, Paes MC, Righi BDP, Bastos JC, Bastos VLFC. Melatonin affects conjugation of 4-hydroxynonenal with glutathione in liver of pacu, a hypoxia-tolerant fish. Fish Physiol Biochem 2013; 39:1205-1214. [PMID: 23440384 DOI: 10.1007/s10695-013-9776-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2012] [Accepted: 02/07/2013] [Indexed: 06/01/2023]
Abstract
In cytosol from liver of pacu, Piaractus mesopotamicus, a hypoxia-tolerant fish that dwells in Pantanal, we found an enzyme activity capable of modulating the alkenal 4-hydroxy-2-nonenal (HNE) by conjugating it with glutathione (GST-HNE activity). HNE is a downstream metabolite from the oxidation of polyunsaturated fatty acids by reactive oxygen species arisen from mitochondria of animal cells. HNE production may increase more intensively under oxidative stress. Harmful effects to cell survival may occur when HNE increases over 10(-4) M. Pacus submitted to hypoxia in July (cold season in Pantanal) showed 40% less of this GST-HNE conjugating activity in their liver cytosol. Injecting pacus subjected to hypoxia during the cold season with a summer physiological dose of melatonin caused their liver cytosolic GST-HNE activity to increase up to the levels found in the warm season. From October to March (warm season in Pantanal), pacus are prone to oxidative stress particularly during potamodromous active oxygen-demanding swimming, when they migrate up rivers to spawn. Thus, our findings point out that the higher levels of melatonin in circulation during the summer are important to avoid the increase of 4-HNE inside liver cells of this fish species.
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Affiliation(s)
- F F Bastos
- Department of Biochemistry, IBRAG, UERJ, Av. Professor Manuel de Abreu, 444, Rio de Janeiro, RJ, 20550-170, Brazil
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Bastos FF, Hauser-Davis RA, Tobar SAL, Campos RC, Ziolli RL, Bastos VLFC, Bastos JC. Enzymatic GST levels and overall health of mullets from contaminated Brazilian Lagoons. Aquat Toxicol 2013; 126:414-423. [PMID: 23010391 DOI: 10.1016/j.aquatox.2012.08.020] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2012] [Revised: 08/24/2012] [Accepted: 08/27/2012] [Indexed: 06/01/2023]
Abstract
Glutathione S-transferase (GST) assays in non-mammalian organisms are usually conducted inappropriately, since no previous standardization of the optimal concentrations of proteins and substrates and adequate pH is conducted. Standardization is a key task to adjust enzyme assays at their kinetically correct maximal initial velocities, if one wants these velocities to indicate the amount of enzyme in a sample. In this paper GST assays were standardized in liver cytosol to compare seasonal GST levels in liver of mullet from two contaminated lagoons in the Rio de Janeiro to those from a reference bay. GST potential as a biomarker of sublethal intoxication in this species was also evaluated. Mullet liver GST levels assayed with substrates that corresponded to three different GST isoenzymes varied throughout the year. The differences indicated that mullets are suffering from sublethal intoxication from contaminants in these lagoons. Seasonal variations of activity were relevant, since these could indicate differences in xenobiotic input into the areas. An analysis of overall mullet health condition using a morphological index (the Fulton Condition Factor) and macroscopic abnormalities corroborated the differences in GST levels, with fish from one of the sites in worse overall health condition showing lower and significantly different FCF when compared to the reference site. Therefore, GST standardized activity levels are useful biomarkers of environmental contamination for mullet.
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Affiliation(s)
- F F Bastos
- UERJ - Biology Institute, Department of Biochemistry, Maracanã, Rio de Janeiro, Brazil
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