Antioxidant enzyme activity in Acidithiobacillus ferrooxidans LR maintained in contact with chalcopyrite

The total protein content and activity of the enzymes glutathione reductase (GR), superoxide dismutase (SOD) and thioredoxin reductase (TrxR) were evaluated in Acidithiobacillus ferrooxidans LR cells maintained in contact with the metal sulfide chalcopyrite for 1 and 10 days. A significant decrease in total protein content was observed in cells maintained for 10 days in the presence of chalcopyrite, suggesting proteolytic breakdown clue to exposure to the metal sulfide. Following 10 clays of contact with chalcopyrite, increases in GR, SOD and TrxR activities were detected, suggesting the formation of reactive oxygen species. After ten clays, there was a fivefold increase in GR activity, of which, isoenzyme IV represented approximately 82% of the total. An increase in Fe-SOD activity following ten days exposure to chalcopyrite was also determined, as measured on non-denaturing polyacrylamide gels. Also, after 10 days. an approximately 31-fold increase was observed for TrxR activity. The presence of oxidative stress when A. ferrooxidans is in the presence of chalcopyrite could have a negative impact on bioleaching. (C) 2010 Elsevier Ltd. All rights reserved.

Bioavailability of dietary sodium copper chlorophyllin and its effect on antioxidant defence parameters of Wistar rats

BACKGROUND: There has been growing interest in sodium copper chlorophyllin (Cu-Chl) as a food colourant and supplement owing to its beneficial biological activities. Studies have revealed that this green pigment inhibits experimental carcinogenesis and interacts with proteins and genotoxic agents. Health-related activities have also been associated with the prevention of lipid peroxidation. However, intestinal absorption of this pigment has been considered insignificant, raising questions of whether eventual biological properties are related to pre- or post-absorptive actions. In this study, intestinal absorption of Cu-Chl and its appearance in serum and organs were estimated by high-performance liquid chromatography analysis in rat feeding experiments. The effect of ingested Cu-Chl on lipid peroxidation was analysed by measuring thiobarbituric acid-reactive substances and antioxidant enzyme activities in hepatic and brain tissues of oxidative stress-induced rats. RESULTS: The two main components of commercial Cu-Chl, namely Cu-chlorin e(6) and Cu-chlorin e(4), showed different digestive behaviours, and only Cu-chlorin e4 was found in serum, liver and kidneys. Antioxidant activity in vivo could be observed in brain and seemed to be related to in situ protection but not to antioxidant enzyme modulation. CONCLUSION: As at least one of the major components of Cu-Chl is effectively absorbed, further pharmacolkinetic studies are encouraged to access absorption rates and the role of ingested copper chlorophyllins in mammals. (C) 2009 Society of Chemical Industry

Oxidative variables and antioxidant enzymes activities in the mdx mouse brain

Dystrophin is a protein found at the plasmatic membrane in muscle and postsynaptic membrane of some neurons, where it plays an important role on synaptic transmission and plasticity. Its absence is associated with Duchenne`s muscular dystrophy (DMD), in which cognitive impairment is found. Oxidative stress appears to be involved in the physiopathology of DMD and its cognitive dysfunction. In this regard, the present study investigated oxidative parameters (lipid and protein peroxidation) and antioxidant enzymes activities (superoxide dismutase and catalase) in prefrontal cortex, cerebellum, hippocampus, striatum and cortex tissues from male dystrophic mdx and normal C57BL10 mice. We observed (I) reduced lipid peroxidation in striatum and protein peroxidation in cerebellum and prefrontal cortex; (2) increased superoxide dismutase activity in cerebellum, prefrontal cortex, hippocampus and striatum: and (3) reduced catalase activity in striatum. It seems by our results, that the superoxide dismutase antioxidant mechanism is playing a protective role against lipid and protein peroxidation in mdx mouse brain. (C) 2009 Elsevier Ltd. All rights reserved.

Diode Laser Decreases the Activity of Catalase on Submandibular Glands of Diabetic Rats

Objective: The aim of this study was to evaluate the effect of laser irradiation on the amylase and the antioxidant enzyme activities, as well as on the total protein concentration of submandibular glands (SMG) of diabetic and non-diabetic rats. Background: Laser has been used aiming to improve some biochemical alterations observed in salivary glands of streptozotocin-induced diabetic rats. Materials and Methods: Ninety-six female rats were divided into eight groups: D0, D5, D10, and D20 (diabetic animals), and C0, C5, C10, and C20 (non-diabetic animals), respectively. Diabetes was induced by administering streptozotocin and confirmed later by the glycemia results. Twenty-nine days after diabetes induction, the SMG of groups D5 and C5, D10 and C10, and D20 and C20 were irradiated with 5, 10, and 20 J/cm(2), respectively. A diode laser (660nm/100mW) was used. On the day after irradiation, the rats were euthanized and the SMG were removed. Catalase, peroxidase, and amylase activities, as well as protein concentration, were assayed. Results: Diabetic rats without irradiation (D0) showed higher catalase activity (p<0.05) when compared to C0 (0.16 +/- 0.05 and 0.07 +/- 0.01 U/mg protein, respectively). However, laser irradiation of 5, 10, and 20 J/cm(2) reduced the catalase activity of diabetic groups (D5 and D20) to non-diabetic values (p>0.05). Conclusion: Based on the results of this study, laser irradiation decreased catalase activity in diabetic rats' SMG.

Fatty acids decrease catalase activity in human leukaemia cell lines

Fatty acid (FA) may disturb the redox state of the cells not only by an increase in reactive oxygen species (ROS) generation but also due to a reduction in antioxidant enzyme activities. The effect of various FAs (palmitic, stearic, oleic, linoleic, gamma-linolenic and eicosapentaenoic acids (EPAs)) on Jurkat and Raji cells, (human T and B leukaemic cell lines was investigated). The following measurements were carried out: FA composition of the cells, cell proliferation and activities of catalase, glutathione peroxidase (GPx) and superoxide dismutase (SOD). The protective effect of alpha-tocopherol on cell death was also investigated. Each cell line presented a specific FA composition. All the tested ENS reduced catalase activity. The toxic effect of FA was abolished by the pre-incubation with physiological concentrations of alpha-tocopherol. The findings support the proposition that the increase in oxidative stress induced by FA partially occurs due to a reduction in catalase activity. In spite of the decrease in the enzyme activity, catalase protein and mRNA levels were not changed, suggesting a post-translational regulation. Copyright (C) 2007 John Wiley & Sons, Ltd.

Oxidative stress biomarkers of exposure in the blood of cichlid species from a metal-contaminated river

The oxidative stress biomarkers of exposure, such as reduced glutathione (GSH), activity of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) and the levels of lipid peroxidation (LPO), were measured in the blood of three cichlid fish (Oreochromis niloticus, Tilapia rendalli, and Geophagus brasiliensis) taken during two seasons from two sites, unpolluted and polluted by industrial effluents, to evaluate the effectiveness of these biomarkers in assessing the impact of water contamination. The LPO levels in the blood were higher in fish from the metal-contaminated site and the chronic exposure led to significant changes in GPx, CAT, and SOD activities in all three cichlid species. The considerable variation of responses in these cichlids to water contamination evidenced differences in sensitivity to the metal contamination and/or in the potential to respond to it highlighting the importance of using a set of related biomarkers to assess the impact of water contamination. (C) 2007 Elsevier Inc. All rights reserved.

Differential ultrastructural changes in tomato hormonal mutants exposed to cadmium

Cadmium (Cd) is a toxic heavy metal, which can cause severe damage to plant development. The aim of this work was to characterize ultrastructural changes induced by Cd in miniature tomato cultivar Micro-Tom (MT) mutants and their wild-type counterpart. Leaves of diageotropica (dgt) and Never ripe (Nr) tomato hormonal mutants and wild-type MT were analysed by light, scanning and transmission electron microscopy in order to characterize the structural changes caused by the exposure to 1 mM CdCl(2). The effect of Cd on leaf ultrastructure was observed most noticeably in the chloroplasts, which exhibited changes in organelle shape and internal organization, of the thylakoid membranes and stroma. Cd caused an increase in the intercellular spaces in Nr leaves, but a decrease in the intercellular spaces in dgt leaves, as well as a decrease in the size of mesophyll cells in the mutants. Roots of the tomato hormonal mutants, when analysed by light microscopy, exhibited alterations in root diameter and disintegration of the epidermis and the external layers of the cortex. A comparative analysis has allowed the identification of specific Cd-induced ultrastructural changes in wild-type tomato, the pattern of which was not always exhibited by the mutants. (C) 2009 Elsevier B.V. All rights reserved.

Biochemical responses of the ethylene-insensitive Never ripe tomato mutant subjected to cadmium and sodium stresses

In order to further address the known interaction between ethylene and components of the oxidative system, we have used the ethylene-insensitive Never ripe (Nr) tomato (Solanum lycopersicum L) mutant, which blocks ethylene responses. The mutant was compared to the control Micro-Tom (MT) cultivar subjected to two stressful situations: 100 mM NaCl and 0.5 mM CdCl(2). Leaf chlorophyll, lipid peroxidation and antioxidant enzyme activities in roots, leaves and fruits, and Na and Cd accumulation in tissues were determined. Although we verified a similar growth pattern and Na and Cd accumulation for MT and Nr, the mutant exhibited reduced leaf chlorophyll degradation following stress. In roots and leaves, the patterns of catalase (CAT), glutathione reductase (GR), ascorbate peroxidase (APX), guaiacol peroxidase (GPOX), superoxide dismutase (SOD) enzyme activity as well as malondialdehyde (MDA) and hydrogen peroxide (H(2)O(2)) production under the stressful conditions tested were very similar between MT and Nr mutant. However, Nr fruits showed increased H(2)O(2) production, reduced and enhanced APX activity in NaCl and CdCl(2), respectively, and enhanced GPOX in NaCl. Moreover, through non-denaturing PAGE, a similar reduction of SOD I band intensity in both, control MT and Nr mutant, treated with NaCl was observed. In leaves and fruits, a similar SOD activity pattern was observed for all periods, genotypes and treatments. Overall the results indicate that the ethylene signaling associated with NR receptor can modulate the biochemical pathways of oxidative stress in a tissue dependent manner, and that this signaling may be different following Na and Cd exposure. (C) 2011 Elsevier B.V. All rights reserved.

Acquired tolerance of tomato (Lycopersicon esculentum cv. Micro-Tom) plants to cadmium-induced stress

The effects of varying concentrations of cadmium (Cd) on the development of Lycopersicon esculentum cv. Micro-Tom (MT) plants were investigated after 40 days (vegetative growth) and 95 days (fruit production), corresponding to 20 days and 75 days of exposure to CdCl(2), respectively. Inhibition of growth was clearly observed in the leaves after 20 days and was greater after 75 days of growth in 1 mM CdCl(2), whereas the fruits exhibited reduced growth following the exposure to a concentration as low as 0.1 mM CdCl(2). Cd was shown to accumulate in the roots after 75 days of growth but was mainly translocated to the upper parts of the plants accumulating to high concentrations in the fruits. Lipid peroxidation was more pronounced in the roots even at 0.05 mM CdCl(2) after 75 days, whereas in leaves, there was a major increase after 20 days of exposure to 1 mM CdCl(2), but the fruit only exhibited a slight significant increase in lipid peroxidation in plants subjected to 1 mM CdCl(2) when compared with the control. Oxidative stress was also investigated by the analysis of four key antioxidant enzymes, which exhibited changes in response to the increasing concentrations of Cd tested. Catalase (EC 1.11.1.6) activity was shown to increase after 75 days of Cd treatment, but the major increases were observed at 0.1 and 0.2 mM CdCl(2), whereas guaiacol peroxidase (EC 1.11.1.7) did not vary significantly from the control in leaves and roots apart from specific changes at 0.5 and 1 mM CdCl(2). The other two enzymes tested, glutathione reductase (EC 1.6.4.2) and superoxide dismutase (SOD, EC 1.15.1.1), did not exhibit any significant changes in activity, apart from a slight decrease in SOD activity at concentrations above 0.2 mM CdCl(2). However, the most striking results were obtained when an extra treatment was used in which a set of plants was subjected to a stepwise increase in CdCl(2) from 0.05 to 1 mM, leading to tolerance of the Cd applied even at the final highest concentration of 1 mM. This apparent adaptation to the toxic effect of Cd was confirmed by biomass values being similar to the control, indicating a tolerance to Cd acquired by the MT plants.

Baroreflex sensitivity and oxidative stress in the LDL receptor knockout mice

This study alms at observing the effect of low-density lipoprotein (LDL) receptor deficiency in cholesterol blood levels, baroreflex sensitivity (BRS), nitric oxide (NO) bioavailability, and oxidative stress. The lack of LDL receptors in mice significantly increased the cholesterol blood levels (179 +/- 35 vs. 109 +/- 13 mg/dL) in the knockout (KO) mice compared to control. There was no difference in basal mean arterial pressure and heart rate between the groups. However, in KO mice the BRS was significantly attenuated and the antioxidant enzyme activities, measured in erythrocytes and heart, were significantly decreased. On the other hand, the oxidative damage measured by chemiluminescence and carbonyls was increased, while total plasma nitrate levels were lower in KO mice, indicating a decrease in NO availability. In conclusion, these results indicate that the lack of LDL receptor increased cholesterol blood levels, induced oxidative stress and decreased BRS. (C) 2008 Elsevier GmbH. All rights reserved.

Testosterone suppresses oxidative stress in human neutrophils

The in vitro effect of testosterone on human neutrophil function was investigated. Blood neutrophils from healthy male subjects were isolated and treated with 10 nM, 0.1 and 10 mu M testosterone for 24 h. As compared with untreated cells, the testosterone treatment produced a significant decrease of superoxide production as indicated by the measurement of extra- and intracellular superoxide content. An increment in the production of nitric oxide was observed at 0.1 and 10 mu M testosterone concentrations, whereas no effect was found for 10 nM. Intracellular calcium mobilization was significantly increased at 10 nM, whereas it was reduced at 10 mu M testosterone. There was an increase in phagocytic capacity at 10 nM and a decrease of microbicidal activity in neutrophils treated with testosterone at 10 mu M. Glutathione reductase activity was increased by testosterone treatment, whereas no effect was observed in other antioxidant enzyme activities. An increase in the content of thiol groups was observed at all testosterone concentrations. Lipid peroxidation in neutrophils evaluated by levels of TBARS was decreased at 10 nM and 0.1 mu M testosterone. These results indicate the antioxidant properties of testosterone in neutrophils as suggested by reduction of superoxide anion production, and lipid peroxidation, and by the increase in nitric oxide production, glutathione reductase activity and the content of thiol groups. Therefore, the plasma levels of testosterone are important regulators of neutrophil function and so of the inflammatory response. Copyright (C) 2010 John Wiley & Sons, Ltd.

Peripheral Oxidative Stress Biomarkers in Mild Cognitive Impairment and Alzheimer`s Disease

Oxidative stress has been associated with normal aging and Alzheimer`s disease (AD). However, little is known about oxidative stress in mild cognitive impairment (MCI) patients who present a high risk for developing AD. The aim of this study was to investigate plasma production of the lipid peroxidation marker, malonaldehyde (MDA) and to determine, in erythrocytes, the enzymatic antioxidant activity of catalase, glutathione peroxidase (GPx), glutathione reductase (GR), and glutathione S-transferase (GST) in 33 individuals with MCI, 29 with mild probable AD and 26 healthy aged subjects. GR/GPx activity ratio was calculated to better assess antioxidant defenses. The relationship between oxidative stress and cognitive performance was also evaluated by the Mini Mental State Examination (MMSE). AD patients showed higher MDA levels than both MCI and healthy elderly subjects. MCI subjects also exhibited higher MDA levels compared to controls. Catalase and GPx activity were similar in MCI and healthy individuals but higher in AD. GR activity was lower in MCI and AD patients than in healthy aged subjects. Additionally, GR/GPx ratio was higher in healthy aged subjects, intermediate in MCI and lower in AD patients. No differences in GST activity were detected among the groups. MMSE was negatively associated with MDA levels (r = -0.31, p = 0.028) and positively correlated with GR/GPx ratio in AD patients (r = 0.68, p < 0.001). MDA levels were also negatively correlated to GR/GPx ratio (r = -0.31, p = 0.029) in the AD group. These results suggest that high lipid peroxidation and decreased antioxidant defenses may be present early in cognitive disorders.

Antioxidant response of Nicotiana tabacum cv. Bright Yellow 2 cells to cadmium and nickel stress

Plant cell cultures are a suitable model system for investigation of the physiological mechanisms of tolerance to environmental stress. We have determined the effects of Cd (0.1 and 0.2 mM CdCl(2)) and Ni (0.075 and 0.75 mM NiCl(2)) on Nicotiana tabacum L. cv. Bright Yellow (TBY-2) cell suspension cultures over a 72-h period. Inhibition of growth, loss of cell viability and lipid peroxidation occurred, in general, only when the TBY-2 cells were grown at 0.2 mM CdCl(2) and at 0.75 mM NiCl(2). At 0.1 mM CdCl(2), a significant increase in growth was determined at the end of the experiment. Increases in the activities of all of the four enzymatic antioxidant defence systems tested, were induced by the two concentrations of Cd and Ni, but at different times during the period of metal exposure. Overall, the cellular antioxidant responses to Cd and Ni were similar and were apparently sufficient to avoid oxidative stress at the lower concentrations of Cd and Ni. The activities of glutathione reductase and glutathione S-transferase increased early but transiently, whereas the activities of catalase and guaiacol peroxidase increased in the latter half of the experimental period. Therefore it is likely that the metabolism of reduced glutathione was enhanced during the initial onset of the stress, while catalase and guaiacol-type peroxidase appeared to play a more important role in the antioxidant response once the stress became severe.

Effect of free or protein-associated soy isoflavones on the antioxidant status in rats

BACKGROUND: The objective of this study was to investigate the effect of chronic ingestion of free and protein-associated soy isoflavones on the antioxidant status in male Wistar rats. Free isoflavone (iso), protein-associated soy isoflavone (iso + prot) and soy protein (prot) extracts were administered for 30 days by gavage to the rats at a dosage of 1 mg aglycone isoflavones per 200 g body weight, adjusted daily, and the prot group was given the same concentration of soy protein received by the iso + prot group. Antioxidant capacity of plasma, thiobarbituric acid-reactive substance (TBARS) and glutathione (GSH) levels and catalase (CAT), glutathione peroxidase (GPx) and superoxide dismutase (SOD) activities in plasma, erythrocytes and tissues and gene expression levels in liver and kidney were evaluated. RESULTS: Chronic ingestion of free but not of protein-associated soy isoflavones nor of solely soy protein increased plasma antioxidant capacity and GPx activity in erythrocytes. Soy protein increased CAT activity and gene expression in liver. SOD activity in erythrocytes was increased by all treatments. CONCLUSION: The overall results confirm that dietary soy isoflavones have a positive effect on antioxidant status, enhancing antioxidant capacity of plasma and antioxidant enzymes in various tissues, but the effects are dependent on the form of administration and on a complex mechanism of antioxidant status balance on the organism. (C) 2010 Society of Chemical Industry

Antioxidant status in rats after long-term intake of anthocyanins and ellagitannins from blackberries

BACKGROUND: This study reported the effects of the daily intake of anthocyanins and ellagitannins (ET) extracted from blackberries on the markers for oxidative status in healthy rats. RESULTS: The phenolic compounds were administered from three different extracts: an aqueous extract of blackberry (BJ) and its two derived fractions: anthocyanin-enriched (AF) and ET-enriched (EF) fractions. After 35 days` administration, the AF and EF extracts significantly reduced thiobarbituric acid reactive substance levels and increased glutathione levels in the liver, kidney and brain. Plasma antioxidant capacity increased only in the group that received AF. Antioxidant enzyme activity and expression did not follow a pattern of response varying according to the tissues and extracts. A significant increase in the catalase activity was observed only in the plasma of the groups administered anthocyanin-containing extracts, which were the BJ and AF groups. Glutathione peroxidase activity was significantly increased in the liver and brain after EF treatment, and the highest increase in its expression was observed in the livers and brains of rats that received AF and EF, respectively. CONCLUSION: The results demonstrate that long-term intake of anthocyanin and ET through diet affects antioxidant enzyme activity and expression, and enhances oxidative markers in healthy rats. (C) 2010 Society of Chemical Industry