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A possible mechanism of low molecular weight protein tyrosine phosphatase (LMW-PTP) activity modulation by glutathione action during human osteoblast differentiation

MALASPINA, Tatiana Salles de Souza; ZAMBUZZI, Willian Fernando; SANTOS, Celio Xavier dos; CAMPANELLI, Ana Paula; LAURINDO, Francisco Rafael Martins; SOGAYAR, Mari Cleide; GRANJEIRO, Jose Mauro
Fonte: PERGAMON-ELSEVIER SCIENCE LTD Publicador: PERGAMON-ELSEVIER SCIENCE LTD
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
36.73%
Objective: Low molecular weight protein tyrosine phosphatases (LMW-PTPs) are a family of enzymes strongly involved in the regulation of cell growth and differentiation. Since there is no information concerning the relationship between osteoblastic differentiation and LMW-PTP expression/activity, we investigated its involvement during human osteoblast-like cells (hFOB 1.19) differentiation. It is known that LMW-PTP is regulated by an elegant redox mechanism, so we also observed how the osteoblastic differentiation affected the reduced glutathione levels. Design: hFOB 1.19 cells were cultured in DMEM/F12 up to 35 days. The osteoblast phenotype acquisition was monitored by measuring alkaline phosphatase activity and mineralized nodule formation by Von Kossa staining. LMW-PTP activity and expression were measured using the p-nitrophenylphosphate as substrate and Western blotting respectively. Crystal violet assay determined the cell number in each experimental point. Glutathione level was determined by both HPLC and DNTB assays. Results: LMW-PTP modulation was coincident with the osteoblastic differentiation biomarkers, such as alkaline phosphatase activity and presence of nodules of mineralization in Vitro. Likewise LMW-PTP, the reduced glutathione-dependent microenvironment was modulated during osteoblastic differentiation. During this process...

Glucose-6-phosphate dehydrogenase and glutathione reductase activity in methemoglobin reduction by methylene blue and cyst amine: study on glucose-6-phosphate dehydrogenase-deficient individuals, on normal subjects and on riboflavin-treated subjects

Barraviera, Benedito; Machado, Paulo Eduardo de Abreu; Meira, Domingos Alves; Curi, Paulo Roberto; Martins, Jair Natal Pires; Souza, Maria Júlia de
Fonte: Instituto de Medicina Tropical Publicador: Instituto de Medicina Tropical
Tipo: Artigo de Revista Científica Formato: 370-378
Português
Relevância na Pesquisa
36.76%
Os autores padronizaram métodos para a avaliação da atividade da glicose-6-fosfato desidrogenase e glutationa redutase. O princípio geral do primeiro método baseou-se na formação de metahemoglobina pelo nitrito de sódio, seguido da estimulação da via das pentoses pelo azul de metileno. Foram estudados 46 indivíduos adultos, sendo 23 do sexo masculino e 23 do feminino, não deficientes em glicose-6-fosfato desidrogenase (G6PD), com idades variando entre 20 e 30 anos. Os resultados revelaram que a redução da metahemoglobina pelo azul de metileno para sangue total, foram de 154.50 e 139.90 mg/min (p<0.05) respectivamente para o sexo masculino e feminino. Para hemácias lavadas os valores foram de 221.10 e 207.85 mg/min (n.s.) respectivamente. Estas observações permitiram concluir que ao se empregar hemácias lavadas e 0.7 g% de concentração de nitrito de sódio, por um lado não houve diferença entre os sexos e por outro, abreviou o tempo de leitura da quantidade residual de metahemoglobina para 90 minutos. A avaliação da atividade da glutationa redutase foi feita baseado no fato de que a cistamina (agente tiol) liga-se aos grupos SH da hemoglobina formando complexos. Estes complexos são revertidos pela ação da glutationa redutase...

AGE-RELATED-CHANGES OF GLUTATHIONE CONTENT, GLUTATHIONE-REDUCTASE AND GLUTATHIONE-PEROXIDASE ACTIVITY OF HUMAN ERYTHROCYTES

Matsubara, L. S.; Machado, PEA
Fonte: Associação Brasileira de Divulgação Científica (ABRADIC) Publicador: Associação Brasileira de Divulgação Científica (ABRADIC)
Tipo: Artigo de Revista Científica Formato: 449-454
Português
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36.83%
1. In order to investigate the effect of aging on the erythrocyte glutathione system, total glutathione (GSH), glutathione reductase (GSH-red) and glutathione peroxidase (GSH-px) levels were measured in erythrocytes from 33 young (mean age = 30.5 +/- 9.7 years) and 28 aged (mean age = 68.9 +/- 11.4 years) healthy individuals.2. GSH was 3.5 +/- 1.8-mu-M/g Hb for the young group, a value significantly greater (P < 0.01) than 2.3 +/- 0.9-mu-M/g Hb found for the aged group. Similarly, GSH-red activity, 5.5 +/- 1.8 IU/g Hb, was higher (P < 0.05) for the young group than 3.4 +/- 0.9 IU/g Hb found for the aged group. The GSH-px activity levels for the young group, 21.1 +/- 5.9 IU/g Hb, were significantly greater (P < 0.01) than 12.0 +/- 3.3 IU/g Hb for the aged group. The lower activity detected in the aged group for all of these parameters of the glutathione redox system was not related to low levels of hematocrit or hemoglobin.3. There was no statistical difference in the activation coefficient (AC) of reductase (+FAD/-FAD) between groups, which seems to indicate that the lower activity of glutathione reductase observed in the aged group was not due to riboflavin deficiency.4. Additional information is required to determine the mechanisms controlling the glutathione redox system and its role in the aging process.

INFLUENCE OF DIABETES-MELLITUS ON THE GLUTATHIONE REDOX SYSTEM OF HUMAN RED-BLOOD-CELLS

Matsubara, L. S.; Ferreira, ALA; Tornero, MTT; Machado, PEA
Fonte: Associação Brasileira de Divulgação Científica (ABRADIC) Publicador: Associação Brasileira de Divulgação Científica (ABRADIC)
Tipo: Artigo de Revista Científica Formato: 331-335
Português
Relevância na Pesquisa
36.76%
Several components of the erythrocyte-dependent glutathione redox system (reduced glutathione, GSH; oxidized glutathione, GSSG; glutathione peroxidase, GSH-Px; glutathione reductase, GSH-Red) were determined in patients with types I and II diabetes mellitus (DM). All groups studied were male subjects: G1, 20 young healthy individuals (aged 23.7 +/- 4.2 years); G2, 15 young insulin-treated type I DM patients; G3, 20 older insulin-treated type II DM patients; 04, 21 older oral hypoglycemic agent-treated type II DM patients; G5, 28 aged healthy individuals (aged 68.9 +/- 11.5 years). There were no differences between G1 and G2, G3 or G4 regarding erythrocyte GSH, GSSG, and GSH-Red (without FAD) levels. GSH-Px activity was significantly lower in G2 when compared to G1 (15.2 +/- 4.9 vs 20.6 +/- 6.6 IU/g Hb). The GSH-Red and GSH-Px activities and GSH levels were significantly higher in 03 (4.6 +/- 1.7 IU/g Hb, 20.2 +/- 8.7 IU/g Hb and 3.5 +/- 1.3-mu-M/g Hb) and G4 (5.0 +/- 2.2 IU/g Hb, 16.9 +/- 6.1 IU/g Hb and 5.0 +/- 2.3-mu-M/g Hb) when compared to G5 (3.4 +/- 0.9 IU/g Hb, 12.0 +/- 3.6 IU/g Hb and 2.3 +/- 0.9-mu-M/g Hb). The findings suggest that treatment of DM can stimulate the redox activity of red blood cells in aged subjects.

Glutathione and glutathione peroxidase expression in breast cancer: An immunohistochemical and molecular study

Jardim, Bruna Victorasso; Moschetta, Marina Gobbe; Leonel, Camila; Gelaleti, Gabriela Bottaro; Regiani, Vitor Rafael; Ferreira, Livia Carvalho; Lopes, Juliana Ramos; De Campos Zuccari, Debora Ap. Pires
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Artigo de Revista Científica Formato: 1119-1128
Português
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36.76%
The use of prognostic markers for breast cancer allows therapeutic strategies to be defined more efficiently. The expression of glutathione (GSH) and glutathione peroxidase (GPX) in tumor cells has been evaluated as a predictor of prognosis and response to cytotoxic treatments. Its immunoexpression was assessed in 63 women diagnosed with invasive ductal carcinoma in a retrospective study. The results showed that high GSH expression was associated with tumors negative for the estrogen receptor (ER) (P<0.05), and GPX expression was associated with tumors negative for the progesterone receptor (PR) and patient mortality. Focusing on the 37 patients who received adjuvant chemotherapy/radiotherapy (Group I), high expression of GPX was associated with a high rate of patient mortality (P<0.05). The 19 patients who received only adjuvant chemotherapy (Group II) showed high expression of GSH in relation to metastasis (P<0.05). In addition, high levels of GPX expression were significantly associated with a shorter overall survival (P<0.05). To confirm this, the expression of precursor genes of GSH [glutamate cysteine ligase (GCLC) and glutathione synthetase (GSS)] and the GPX gene was analyzed using quantitative PCR in cultured neoplastic mammary cells treated with doxorubicin. Doxorubicin treatment was able to eliminate tumor cells without alterations in the gene expression of GSS...

Expression of glutathione, glutathione peroxidase and glutathione S-transferase pi in canine mammary tumors

Leonel, Camila; Gelaleti, Gabriela B.; Jardim, Bruna V.; Moschetta, Marina G.; Regiani, Vitor R.; Oliveira, Juliana G.; Zuccari, Debora A. P. C.
Fonte: Biomed Central Ltd. Publicador: Biomed Central Ltd.
Tipo: Artigo de Revista Científica Formato: 10
Português
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES); Background: Glutathione (GSH) is one of the most important agents of the antioxidant defense system of the cell because, in conjunction with the enzymes glutathione peroxidase (GSH-Px) and glutathione S transferase pi (GSTpi), it plays a central role in the detoxification and biotransformation of chemotherapeutic drugs. This study evaluated the expression of GSH and the GSH-Px and GSTpi enzymes by immunohistochemistry in 30 canine mammary tumors, relating the clinicopathological parameters, clinical outcome and survival of the bitches. In an in vitro study, the expression of the genes glutamate cysteine ligase (GCLC) and glutathione synthetase (GSS) that synthesize GSH and GSH-Px gene were verified by qPCR and subjected to treatment with doxorubicin, to check the resistance of cancer cells to chemotherapy.Results: The immunohistochemical expression of GSH, GSH-Px and GSTpi was compared with the clinical and pathological characteristics and the clinical outcome in the bitches, including metastasis and death. The results showed that high immunoexpression of GSH was correlated to the absence of tumor ulceration and was present in dogs without metastasis (P < 0.05). There was significant correlation of survival with the increase of GSH (P < 0.05). The expression of the GSH-Px and GSTpi enzymes showed no statistically significant correlation with the analyzed variables (p > 0.05). The analysis of the relative expression of genes responsible for the synthesis of GSH (GCLC and GSS) and GSH-Px by quantitative PCR was done with cultured cells of 10 tumor fragments from dogs with mammary tumors.The culture cells showed a decrease in GCLC and GSS expression when compared with no treated cells (P < 0.05). High GSH immunoexpression was associated with better clinical outcomes.Conclusion: Therefore...

Desenvolvimento de um eletrodo amperometrico para determinação de glutationa em eritrocitos; Development of an amperometric electrode for determination of glutathione in erythrocytes

Percy Calvo Marzal
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 08/08/2005 Português
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O presente trabalho refere-se ao desenvolvimento de um novo método para determinação de glutationa em eritrócitos, utilizando o método amperométrico. Para isto um eletrodo a base de pasta de carbono modificado com o complexo tetratiofulvaleno-tetracianoquinodimetano (TTF-TCNQ) foi desenvolvido, com o intuito de possibilitar a transferência de elétrons entre a glutationa e o eletrodo a baixos potenciais. O eletrodo modificado apresentou boas características em termos de seletividade, sensibilidade e tempo de resposta, facilitando sua operacionalidade para a detecção de glutationa. Com a modificação do eletrodo foi possível obter uma resposta bastante sensível para glutationa num potencial de 200 mV vs ECS. As melhores condições foram verificadas com 20% (m/m) de TTF-TCNQ incorporado na pasta de carbono e 0,5% de Nafion (m/v). As medidas foram realizadas em tampão fosfato pH 8,0 contendo KCl 0,1 mol L e EDTA 0,5 mmol L. Nessas condições, o eletrodo modificado apresentou um intervalo de resposta linear entre 5 a 340 mmol L de glutationa ajustado pela equação Dj = 0,7(±0,1) + 90,1(±0,4)[GSH] com um coeficiente de correlação de 0.9998 para n = 20, onde a densidade de corrente Dj é dada em mA cm e a concentração da GSH em mmol L. O tempo de resposta do eletrodo foi de 0...

A possible mechanism of low molecular weight protein tyrosine phosphatase (LMW-PTP) activity modulation by glutathione action during human osteoblast differentiation

MALASPINA, Tatiana Salles de Souza; ZAMBUZZI, Willian Fernando; SANTOS, Celio Xavier dos; CAMPANELLI, Ana Paula; LAURINDO, Francisco Rafael Martins; SOGAYAR, Mari Cleide; GRANJEIRO, Jose Mauro
Fonte: PERGAMON-ELSEVIER SCIENCE LTD Publicador: PERGAMON-ELSEVIER SCIENCE LTD
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
36.73%
Objective: Low molecular weight protein tyrosine phosphatases (LMW-PTPs) are a family of enzymes strongly involved in the regulation of cell growth and differentiation. Since there is no information concerning the relationship between osteoblastic differentiation and LMW-PTP expression/activity, we investigated its involvement during human osteoblast-like cells (hFOB 1.19) differentiation. It is known that LMW-PTP is regulated by an elegant redox mechanism, so we also observed how the osteoblastic differentiation affected the reduced glutathione levels. Design: hFOB 1.19 cells were cultured in DMEM/F12 up to 35 days. The osteoblast phenotype acquisition was monitored by measuring alkaline phosphatase activity and mineralized nodule formation by Von Kossa staining. LMW-PTP activity and expression were measured using the p-nitrophenylphosphate as substrate and Western blotting respectively. Crystal violet assay determined the cell number in each experimental point. Glutathione level was determined by both HPLC and DNTB assays. Results: LMW-PTP modulation was coincident with the osteoblastic differentiation biomarkers, such as alkaline phosphatase activity and presence of nodules of mineralization in Vitro. Likewise LMW-PTP, the reduced glutathione-dependent microenvironment was modulated during osteoblastic differentiation. During this process...

Glucose-6-phosphate dehydrogenase and glutathione reductase activity in methemoglobin reduction by methylene blue and cyst amine: study on glucose-6-phosphate dehydrogenase-deficient individuals, on normal subjects and on riboflavin-treated subjects

Barraviera,Benedito; Machado,Paulo Eduardo de Abreu; Meira,Domingos Alves; Curi,Paulo Roberto; Martins,Jair Natal Pires; Souza,Maria Júlia de
Fonte: Instituto de Medicina Tropical Publicador: Instituto de Medicina Tropical
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/10/1988 Português
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36.76%
The authors have standardized methods for evaluation of the activity of the glucose-6-phosphate dehydrogenase and of glutathione reductase. The general principle of the first method was based on methemoglobin formation by sodium nitrite followed by stimulation of the glucose-6-phosphate dehydrogenase with methylene blue. Forty six adults (23 males and 23 females) were studied. Subjects were not G6PD deficient and were aged 20 to 30 years. The results showed that methemoglobin reduction by methylene blue was 154.40 and 139.90 mg/min (p<0.05) for males and females, respectively, in whole blood, and 221.10 and 207.85 mg/min (n.s.), respectively, in washed red cells. These data showed that using washed red cells and 0.7g% sodium nitrite concentration produced no differences between sexes and also shortened reading time for the residual amount of methemoglobin to 90 minutes. Glutathione reductase activity was evaluated on the basis of the fact that cystamine (a thiol agent) binds to the SH groups of hemoglobin, forming complexes. These complexes are reversed by the action of glutathione reductase, with methemoglobin reduction occurring simultaneously with this reaction. Thirty two adults (16 males and 16 females) were studied. Subjects were not G6PD deficient and were aged 20 to 30 years. Methemoglobin reduction by cystamine was 81.27 and 91.13 mg/min (p<0.01) for males and females...

Glutathione and the redox control system trypanothione/trypanothione reductase are involved in the protection of Leishmania spp. against nitrosothiol-induced cytotoxicity

Romão,P.R.T.; Tovar,J.; Fonseca,S.G.; Moraes,R.H.; Cruz,A.K.; Hothersall,J.S.; Noronha-Dutra,A.A.; Ferreira,S.H.; Cunha,F.Q.
Fonte: Associação Brasileira de Divulgação Científica Publicador: Associação Brasileira de Divulgação Científica
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/03/2006 Português
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36.76%
Glutathione is the major intracellular antioxidant thiol protecting mammalian cells against oxidative stress induced by oxygen- and nitrogen-derived reactive species. In trypanosomes and leishmanias, trypanothione plays a central role in parasite protection against mammalian host defence systems by recycling trypanothione disulphide by the enzyme trypanothione reductase. Although Kinetoplastida parasites lack glutathione reductase, they maintain significant levels of glutathione. The aim of this study was to use Leishmania donovani trypanothione reductase gene mutant clones and different Leishmania species to examine the role of these two individual thiol systems in the protection mechanism against S-nitroso-N-acetyl-D,L-penicillamine (SNAP), a nitrogen-derived reactive species donor. We found that the resistance to SNAP of different species of Leishmania was inversely correlated with their glutathione concentration but not with their total low-molecular weight thiol content (about 0.18 nmol/10(7) parasites, regardless Leishmania species). The glutathione concentration in L. amazonensis, L. donovani, L. major, and L. braziliensis were 0.12, 0.10, 0.08, and 0.04 nmol/10(7) parasites, respectively. L. amazonensis, that have a higher level of glutathione...

Streptococcus pneumoniae uses glutathione to defend against oxidative stress and metal ion toxicity

Potter, A.; Trappetti, C.; Paton, J.
Fonte: Amer Soc Microbiology Publicador: Amer Soc Microbiology
Tipo: Artigo de Revista Científica
Publicado em //2012 Português
Relevância na Pesquisa
36.76%
The thiol-containing tripeptide glutathione is an important cellular constituent of many eukaryotic and prokaryotic cells. In addition to its disulfide reductase activity, glutathione is known to protect cells from many forms of physiological stress. This report represents the first investigation into the role of glutathione in the Gram-positive pathogen Streptococcus pneumoniae. We demonstrate that pneumococci import extracellular glutathione using the ABC transporter substrate binding protein GshT. Mutation of gshT and the gene encoding glutathione reductase (gor) increases pneumococcal sensitivity to the superoxide generating compound paraquat, illustrating the importance of glutathione utilization in pneumococcal oxidative stress resistance. In addition, the gshT and gor mutant strains are hypersensitive to challenge with the divalent metal ions copper, cadmium, and zinc. The importance of glutathione utilization in pneumococcal colonization and invasion of the host is demonstrated by the attenuated phenotype of the gshT mutant strain in a mouse model of infection.; Adam J. Potter, Claudia Trappetti, and James C. Paton

Wege des Exports von Glutathion aus Astrocyten; Paths of glutathione export from astrocytes

Minich, Tobias Florian
Fonte: Universidade de Tubinga Publicador: Universidade de Tubinga
Tipo: Dissertação
Português
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36.86%
Vorliegender Arbeit lag die Aufgabe zugrunde herauszufinden, welche(s) Transportsystem(e) außer dem Multidrug-Transporter 1 (multidrug resistance protein 1, MRP1) zum Austritt des Tripeptides Glutathion aus Primärkulturen von Astrogliazellen in das extrazelluläre Milieu beitragen. Als Grundlage für die Untersuchungen wurde zunächst an zwei Wildtyp Mausstämmen (NMRI und FVB/N) sichergestellt, dass astrogliareiche Primärkulturen aus Mäusen sowohl reduziertes als auch oxidiertes Glutathion exportieren. Die Kulturen unterschieden sich lediglich in quantitativer Hinsicht in Transportgeschwindigkeit und in Beeinflussbarkeit durch Mk571, einen Mrp1-Inhibitor. Die Transportcharakteristika analoger Kulturen aus FVB/N-Mäusen, dem Wildtyp von Mrp1-Knockout- und Mrp5-Knockout-Stämmen, glichen jedoch denen astrogliareicher Primärkulturen aus Ratte. So exportierten beide bei Anwendung von oxidativem Dauerstress innerhalb von 45 Minuten etwa 50 % des gesamt Gesamtglutathions in oxidierter Form, Kulturen aus NMRI-Mäusen nur etwa 25 % . Die Feststellung dieser Ähnlichkeit war wichtig, da der Mrp1-vermittelte Efflux von reduziertem und oxidiertem Glutathion ursprünglich an Rattenkulturen untersucht worden war, Studien an Kulturen aus Knockout-Tieren aber nur mit Mäusen möglich sind. Untersuchungen an Astrogliakulturen aus Mrp1-Knockout-Mäusen ergaben...

Zytotoxizität von Treosulfan nach Glutathiondepletion durch BSO bei humanen Glioblastomzellen; cytotoxicity of treosulfan after BSO-induced glutathione depletion in glioma cells

Stock, Jan
Fonte: Universidade de Tubinga Publicador: Universidade de Tubinga
Tipo: Dissertação
Português
Relevância na Pesquisa
36.73%
Hintergrund: Trotz beachtlicher Fortschritte in der Tumortherapie, wurde für Patienten mit malignem Gliom, dem häufigsten hirneigenen Tumor im Erwachsenenalter, die Prognose kaum verbessert. Zytostatikaresistenz ist ein entscheidender Faktor, durch den die Chemotherapie maligner Gliome nur zu unbefriedigenden Ergebnissen führt. In einer kürzlich erschienen Arbeit konnte an zwei Zelllinien maligner Gliome die Zytostaikaresistenz durch eine Kombinationsbehandlung mit Treosulfan, einem Alkylanz, und D, L-Buthionin-[S, R]-Sulfoximin (BSO), ein Glutathion-Synthetase-Hemmer, überwunden werden. In der Literatur gibt es Hinweise auf eine Beteiligung von Glutathion bei der Zellantwort auf CD95L und TNF-alpha. Deshalb wurde untersucht, ob eine Resistenzüberwindung durch Glutathion-Depletion mit BSO und die damit verbundene erhöhte Empfindlichkeit gegenüber der Zytotoxizität von Treosulfan möglicherweise mit dem CD95/CD95L-System in Verbindung steht. Maligne Gliomzellen sind gegenüber TNF-alpha-vermittelte Zytotoxizität nicht empfindlich. Daher war auch von Interesse, ob bei malignen Gliomzellen durch BSO gegenüber TNF-alpha Zytotoxizität induziert werden kann. Methoden und Ergebnisse: Alle zwölf humanen malignen Gliomzelllinien (T98G...

A FACTORIAL DESIGN APPLIED TO THE STUDY OF CHROMIUM TOXICITY ON THE GLUTATHIONE LEVELS OF Brachiaria brizantha AND Brachiaria ruziziensis SEEDLINGS

Marques,Rafael; Oliveira,Marcone A. L. de; Reis,Cassia R. G. dos; Köpp,Maurício M.; Passos,Leônidas P.
Fonte: Sociedade Brasileira de Química Publicador: Sociedade Brasileira de Química
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/08/2015 Português
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36.76%
Chromium toxicity affects redox reactions within plant cells, generating detrimental reactive oxygen species. Glutathione is an antioxidant peptide and also a substrate for the production of phytochelatins, which are chelating peptides reported to mitigate Cr3+ toxicity in plants. In this study, Brachiaria brizantha (B. brizantha) and Brachiaria ruziziensis (B. ruziziensis) seedlings were evaluated for physiological responses and glutathione production following the addition of zero or 5 mg L-1 Cr3+ to the nutrient solution. Glutathione levels were determined by colorimetric analysis at 412 nm using 5,5'-dithio-bis(2-nitrobenzoic acid) as a chromophore reagent and recovery with glutathione reductase (with evaluations at days 10 and 20 of continuous growth). The assessments were carried out in a completely randomized design with 2 authentic replications, and arranged in a 23 factorial. Cr3+ caused an average increase of 0.76 mg g-1 in the initial glutathione content. However, by day 20 there was an average reduction of 3.63 mg g-1. Chromium-affected physiological detrimental responses, albeit detected in both species, were less-pronounced in B. ruziziensis, along with a much higher level of glutathione. This study indicates that B. ruziziensis has a greater tolerance for chromium toxicity than B. brizantha...

Changes in endogenous tissue glutathione level in relation to murine ascites tumor growth and the anticancer activity of cisplatin

Khynriam,D.; Prasad,S.B.
Fonte: Associação Brasileira de Divulgação Científica Publicador: Associação Brasileira de Divulgação Científica
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2003 Português
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36.81%
Changes in glutathione levels were determined in tissues of 11- to 12-week-old Swiss albino mice at different stages of Dalton's lymphoma tumor growth and following cisplatin (8 mg/kg body weight, ip) treatment for 24-96 h, keeping 4-5 animals in each experimental group. Glutathione levels increased in spleen of tumor-bearing compared to normal mice (9.95 ± 0.14 vs 7.86 ± 1.64 µmol/g wet weight, P<=0.05) but decreased in blood (0.64 ± 0.10 vs 0.85 ± 0.09 mg/ml) and testes (9.28 ± 0.15 vs 10.16 ± 0.28 µmol/g wet weight, P<=0.05). Dalton's lymphoma cells showed an increase in glutathione concentration (4.43 ± 0.26 µmol/g wet weight) as compared to splenocytes, their normal counterpart (3.62 ± 0.41 µmol/g wet weight). With the progression of tumor in mice, glutathione levels decreased significantly in testes (~10%) and bone marrow cells (~13%) while they increased in Dalton's lymphoma cells (28-46%) and spleen (15-27%). Glutathione levels in kidney, Dalton's lymphoma cells and bone marrow cells (8.50 ± 1.22, 4.43 ± 0.26 and 3.28 ± 0.17 µmol/g wet weight, respectively) decreased significantly (6.04 ± 0.42, 3.51 ± 0.32 and 2.17 ± 0.14 µmol/g wet weight, P<=0.05) after in vivo cisplatin treatment for 24 h. Along with a decrease in glutathione level...

Rapid Capillary Electrophoresis Analysis of Glutathione and Glutathione Disulfide in Roots and Shoots of Plants Exposed to Copper

Parada, José; Riveros Salvatierra, Raúl; Garrido Reyes, Tatiana Inés; Mendoza, Jorge
Fonte: JOHN WILEY & SONS LTD Publicador: JOHN WILEY & SONS LTD
Tipo: Artículo de revista
Português
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36.8%
Introduction - Glutathione and glutathione disulfide can be determined by capillary zone electrophoresis; however, the frequent use of acidic precipitation of protein from samples prior to analysis generates an acidic matrix of strength and pH that may cause changes in the method sensitivity, comigration of species or changes in the equilibria that relate both species in cells or fluids. Objective - To optimise electrophoretic conditions for glutathione and glutathione disulfide determination, and to improve pre-analytical treatment for better visualization of the signals of both peptides in an acidic matrix. Methodology - The method consisted of direct photometric detection at 185 nm and 300 mm borate at pH 7.6 as background electrolyte. The variables under study were voltage applied, injection time, capillary length and electrolyte pH. Seedlings were hydroponically grown and the peptides were extracted with metaphosphoric acid. Results - The resulting acidic matrix was previously treated with the same background electrolyte to prevent comigration and to improve signal resolution. The optimised method showed good reproducibility and linearity, with correlation coefficients above 0.999 and detection limits below 3 mu m, and determination of both analytes in less than 3 min. Analyte recovery in the process was in the 88-104% range. The concentration range found in hydroponically grown tomato plants...

A novel selenium-containing glutathione transferase zeta1-1, the activity of which surpasses the level of some native glutathione peroxidases

Zheng, Keyan; Board, Philip; Fei, Xiaofang; Sun, Ye; Lv, Shaowu; Yan, Ganglin; Liu, Junqiu; Shen, Jiacong; Luo, Guimin
Fonte: Pergamon-Elsevier Ltd Publicador: Pergamon-Elsevier Ltd
Tipo: Artigo de Revista Científica
Português
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36.78%
Glutathione peroxidase (GPX) is a critical antioxidant selenoenzyme in organisms that protects cells against oxidative damage by catalyzing the reduction of hydroperoxides by glutathione (GSH). Thus, some GPX mimics have been generated because of their po

The use of glutathione transferase-knockout mice as pharmacological and toxicological models

Board, Philip
Fonte: Ashley Publications Ltd Publicador: Ashley Publications Ltd
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
36.8%
ADME/Tox studies are of increasing importance because of the necessity to eliminate poor drug candidates early in the development pipeline. The glutathione S-transferases (GSTs) are a family of phase II enzymes that have been shown to play a significant r

Nomenclature for Mammalian soluble glutathione transferases

Mannervik, Bengt; Board, Philip; Hayes, John D; Listowsky, Irving; Pearson, William R
Fonte: Elsevier Publicador: Elsevier
Tipo: Parte de Livro
Português
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The nomenclature for human soluble glutathione transferases (GSTs) is extended to include new members of the GST superfamily that have been discovered, sequenced, and shown to be expressed. The GST nomenclature is based on primary structure similarities and the division of GSTs into classes of more closely related sequences. The classes are designated by the names of the Greek letters: Alpha, Mu, Pi, etc., abbreviated in Roman capitals: A, M, P, and so on. (The Greek characters should not be used.) Class members are distinguished by Arabic numerals and the native dimeric protein structures are named according to their subunit composition (e.g., GST A1-2 is the enzyme composed of subunits 1 and 2 in the Alpha class). Soluble GSTs from other mammalian species can be classified in the same manner as the human enzymes, and this chapter presents the application of the nomenclature to the rat and mouse GSTs.

Clarification of the role of key active site residues of glutathione transferase Zeta/maleylacetoacetate isomerase by a new spectrophotometric technique

Board, Philip; Taylor, Matthew; Coggan, Marjorie; Parker, Michael William; Lantum, Hoffman; Anders, Michael
Fonte: Portland Press Publicador: Portland Press
Tipo: Artigo de Revista Científica
Português
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hGSTZ1-1 (human glutathione transferase Zeta 1-1) catalyses a range of glutathione-dependent reactions and plays an important role in the metabolism of tyrosine via its maleylacetoacetate isomerase activity. The crystal structure and sequence alignment of hGSTZ1 with other GSTs (glutathione transferases) focused attention on three highly conserved residues (Ser-14, Ser-15, Cys-16) as candidates for an important role in catalysis. Progress in the investigation of these residues has been limited by the absence of a convenient assay for kinetic analysis. In this study we have developed a new spectrophotometric assay with a novel substrate [(± )-2-bromo-3-(4-nitrophenyl)propionic acid]. The assay has been used to rapidly assess the potential catalytic role of several residues in the active site. Despite its less favourable orientation in the crystal structure, Ser-14 was the only residue found to be essential for catalysis. It is proposed that a conformational change may favourably reposition the hydroxyl of Ser-14 during the catalytic cycle. The Cys16 → Ala (Cys-16 mutated to Ala) mutation caused a dramatic increase in the Km for glutathione, indicating that Cys-16 plays an important role in the binding and orientation of glutathione in the active site. Previous structural studies implicated Arg-175 in the orientation of α-halo acid substrates in the active site of hGSTZ1-1. Mutation of Arg-175 to Lys or Ala resulted in a significant lowering of the kcat in the Ala-175 variant. This result is consistent with the proposal that the charged side chain of Arg-175 forms a salt bridge with the carboxylate of the α-halo acid substrates.