Irradiance stress responses of gas exchange and antioxidant enzyme contents in pariparoba [Pothomorphe umbellata (L.) Miq.] plants

We evaluated the growth and development of the medicinal species Pothomorphe umbellata ( L.) Miq. under different shade levels ( full sun and 30, 50, and 70 % shade, marked as I(100), I(70), I(50), and I(30), respectively) and their effects on gas exchange and activities of antioxidant enzymes. Photosynthetically active radiation varied from 1 254 mu mol m(-2) s(-1) at I(100) to 285 mu mol m(-2) s(-1) at I(30). Stomatal conductance, net photosynthetic rate, and relative chlorophyll (Chl) content were maximal in I(70) plants. Plants grown under I(100) produced leaves with lower Chl content and signs of chlorosis and necrosis. These symptoms indicated Chl degradation induced by the generation of reactive oxygen species. Stress related antioxidant enzyme activities ( Mn-SOD, Fe-SOD, and Cu/Zn-SOD) were highest in I(100) plants, whereas catalase activity was the lowest. Hence P. umbellata is a shade species ( sciophyte), a feature that should be considered in reforestation programs or in field plantings for production of medicinal constituents.

Antioxidant enzyme activity and hydrogen peroxide content during the drying of Arabica coffee beans

The development of the germination process and drought stress during the drying of coffee can generate reactive oxygen species, which can be neutralized by way of antioxidant mechanisms. No studies related to antioxidant enzymes during the drying of coffee were found in the literature, and considering their importance, the enzymatic activities of superoxide dismutase (SOD), guaiacol peroxidase (GPOX) and glutathione reductase (GR), and also the hydrogen peroxide content were evaluated during the drying of two types of coffee bean, one processed as natural coffee and the other as pulped natural coffee. The results showed a reduction in the SOD, GPOX and GR enzymatic activities of the natural coffee as compared to the pulped natural coffee during the drying period. Moreover, the hydrogen peroxide content of the natural coffee was greater than that of the pulped natural coffee. These results suggest the development of oxidative stress during the coffee drying process, controlled more efficiently in pulped natural coffee by the early action of GPOX during the drying process. Nevertheless, differential responses by SOD isoenzymes and possibly the role of other peroxidases also appear to be involved in the responses observed. © 2013 Springer-Verlag Berlin Heidelberg.

The long-term administration of calcineurin inhibitors decreases antioxidant enzyme activity in the rat parotid and submandibular salivary glands

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Healing, Antioxidant and Cytoprotective Properties of Indigofera truxillensis in Different Models of Gastric Ulcer in Rats

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Evaluation of lipid profile and oxidative stress in STZ-induced rats treated with antioxidant vitamin

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Kinetic study of the plastoquinone pool availability correlated with H2O2 release in seawater and antioxidant responses in the red alga Kappaphycus alvarezii exposed to single or combined high light, chilling and chemical stresses

Under biotic/abiotic stresses, the red alga Kappaphycus alvarezii reportedly releases massive amounts of H2O2 into the surrounding seawater. As an essential redox signal, the role of chloroplast-originated H2O2 in the orchestration of overall antioxidant responses in algal species has thus been questioned. This work purported to study the kinetic decay profiles of the redox-sensitive plastoquinone pool correlated to H2O2 release in seawater, parameters of oxidative lesions and antioxidant enzyme activities in the red alga Kappaphycus alvarezii under the single or combined effects of high light, low temperature, and sub-lethal doses of 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU) and 2,5-dibromo-3-methyl-6-isopropyl-p-benzoquinone (DBMIB), which are inhibitors of the thylakoid electron transport system. Within 24 h, high light and chilling stresses distinctly affected the availability of the PQ pool for photosynthesis, following Gaussian and exponential kinetic profiles, respectively, whereas combined stimuli were mostly reflected in exponential decays. No significant correlation was found in a comparison of the PQ pool levels after 24 h with either catalase (CAT) or ascorbate peroxidase (APX) activities, although the H2O2 concentration in seawater (R = 0.673), total superoxide dismutase activity (R = 0.689), and particularly indexes of protein (R = 0.869) and lipid oxidation (R = 0.864), were moderately correlated. These data suggest that the release of H2O2 from plastids into seawater possibly impaired efficient and immediate responses of pivotal H2O2-scavenging activities of CAT and APX in the red alga K. alvarezii, culminating in short-term exacerbated levels of protein and lipid oxidation. These facts provided a molecular basis for the recognized limited resistance of the red alga K. alvarezii under unfavorable conditions, especially under chilling stress. © 2006 Elsevier B.V. All rights reserved.

Biochemical dissection of diageotropica and Never ripe tomato mutants to Cd-stressful conditions

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Protection of insulin-producing cells against toxicity of dexamethasone by catalase overexpression

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Neonatally-induced diabetes: lipid profile outcomes and oxidative stress status in adult rats

INTRODUÇÃO: Modelos experimentais são desenvolvidos com propósito de ampliar o entendimento dos mecanismos fisiopatológicos envolvidos no diabete. Os achados experimentais levam ao desenvolvimento de tratamentos alternativos para a manutenção das condições metabólicas normais. Existem vários estudos sobre o diabete induzido por streptozotocin mimetizando o quadro clínico do DM2. No entanto, a interação entre os níveis de glicose, perfil lipídico e estresse oxidativo nestes animais são escassos. Portanto, o objetivo do trabalho foi avaliar estes parâmetros em ratas Wistar adultas com diabete induzido com streptozotocin no período neonatal. MÉTODOS: Fêmeas recém-nascidas receberam streptozotocin (70mg/Kg, ip) no 5º dia de vida (n5-STZ). A glicemia foi medida no terceiro e quarto meses de vida dos animais. No final do quarto mês de vida, amostras de sangue foram coletadas e processadas para a dosagem de lipídios e marcadores de estresse oxidativo. RESULTADOS: A glicemia das ratas do grupo n5-STZ foi significativamente maior comparada às ratas do grupo controle (p<0,05). Não houve alteração nos níveis de colesterol total e triglicérides, peroxidação lipídica (TBARS), atividade da SOD e determinação da GSH-t (p>0,05) nas ratas n5-STZ em relação às ratas do grupo controle. No entanto, houve diminuição significativa no HDL-colesterol (p<0,05). CONCLUSÃO: Este modelo de indução de diabete em ratas causou hiperglicemia (120-360mg/dL), caracterizando o diabete moderado. Essa glicemia levou a alterações no HDL-colesterol, a qual não foi suficiente para prejudicar a atividade das enzimas antioxidantes ou marcadores da peroxidação lipídica na vida adulta. Além disso, esta investigação experimental contribuiu para entender os diferentes resultados encontrados em outros modelos deindução do diabete moderado em animais de laboratório, como também para a melhor compreensão dos mecanismos fisiopatológicos do diabete moderado ou da hiperglicemia em humanos.

Differential morphofunctional characteristics and gene expression in fast and slow muscle of rats with monocrotaline-induced heart failure

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Tobacco Smoke Induces Ventricular Remodeling Associated with an Increase in NADPH Oxidase Activity

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Burnt sugarcane harvesting: Particulate matter exposure and the effects on lung function, oxidative stress, and urinary 1-hydroxypyrene

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Early cytotoxic and genotoxic effects of atrazine on Wistar rat liver: A morphological, immunohistochemical, biochemical, and molecular study

Risk assessments suggest that intermediate and long-term exposure to triazine herbicides and its metabolites through water can cause severe damage to human health. The objective of this study was to investigate the possible effects of atrazine on Wistar rats submitted to subacute treatment. For this purpose, the activity of catalase and alanine aminotransferase was quantified, and the effect of the herbicide on cell membranes was examined based on the measurement of lipid peroxidation and consequent formation of malondialdehyde and on the mRNA expression of antioxidant enzymes (Mn-superoxide dismutase [SOD] and GSTM1) and connexins. In addition, we evaluated histopathological alterations in the liver, cellular expression of SOD and glutathione (GST), activation of heat shock proteins (HSPs) by immunohistochemistry, and the induction of apoptosis. The genotoxic potential of the herbicide was investigated by the micronucleus test in bone marrow smears. Adult male Wistar rats were treated with an aqueous solution of atrazine at a concentration of 400 mg/kg/day, by gavage, for 14 consecutive days. Control groups were also included. The results showed an increase of catalase levels and maintenance of the expression of antioxidant enzymes (SOD and GST). In addition, lipid peroxidation, hepatic tissue degeneration, activation of HSP90, increased levels of connexin mRNA, and genotoxicity were observed. In conclusion, atrazine induced early hepatic oxidative stress that triggered defense mechanisms to maintain the morphophysiological integrity of the liver. Further studies are needed to better understand the effects of this herbicide on human health. (C) 2011 Elsevier B.V. All rights reserved.

Dietary restriction: Metabolic shifting for cardiac health

Purpose: To determine the effect of dietary restriction on metabolic pathways and the relationship of the metabolic shifting on antioxidant enzymes in cardiac tissue. Design: Randomized, controlled study. Male rats at 60 days old were randomly divided into four groups. Materials and Methods: The rats of control groups C30 and C60 were given free access to the diet over 30 and 60 days. The rats of the DR30 group were fed 60% of the chow consumed by the control groups over 30 days. The animals of the DR60 group ate 60% of the amount consumed by the C60 group over 60 days. Serum was used for total protein, lactate dehydrogenase (LDH), alanine aminotransferase (ALT) and aspartate aminotransferase (AST). Protein, glycogen, total lipids, superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), LDH, AST and ALT were determined in cardiac tissue. Results: Dietary restriction induced diminished serum and cardiac LDH activities. AST activities were lower in the serum and cardiac muscle of the DR60 animals. Dietary restriction induced elevated total lipid concentrations in cardiac muscle. No significant differences were observed in total protein and glycogen content among the groups. Antioxidant enzyme determinations demonstrated increased cardiac GSH-Px activities in the DR60 animals and increased SOD activities in the cardiac tissue of both feed-restricted groups. Conclusions: Dietary restriction was protective against oxidative stress in the heart by improving cardiac endogenous antioxidant defences and shifting the metabolic pathway for energy production.

Influence of treatment with quercetin on lipid parameters and oxidative stress of pregnant diabetic rats

Among the numerous coadjuvant therapies that could influence the incidence and progression of diabetic complications, antioxidants and flavonoids are currently being tested in clinical trials. We investigated the effect of quercetin on biochemical parameters in streptozotocin-induced (60 mg/kg body mass, by intraperitoneal injection) diabetic rats. A total of 32 female Wistar rats were distributed among 4 groups as follows: control (G1); control treated with quercetin (G2); diabetic (G3); and diabetic treated with quercetin (G4). Quercetin administered to pregnant diabetic rats controlled dyslipidemia and improved lipid profiles in diabetes mellitus, regulated oxidative stress by reducing the generation of lipid hydroperoxides, and increased the activity of the antioxidant enzyme glutathione peroxidase.