Zinc Superoxide Dismutase Activity Research Articles

The Evaluation of the Oxidative Stress Parameters in Nondiabetic and Diabetic Senile Cataract Patients

The aim of the present study was to evaluate the copper (Cu), zinc (Zn), malondialdehyde (MDA), glutathione (GSH), and advanced oxidation protein products (AOPP) levels and superoxide dismutase (SOD) activities in diabetic senile cataract. Ten patients with diabetic senile cataract and ten patients with nondiabetic senile cataract (control group) were included in this study. AOPP, MDA, and GSH levels and SOD activity were measured by a spectrophotometric method. Serum, lens Cu, and Zn levels were measured by an atomic absorption spectrophotometric method. Both the lens and serum Zn and Cu levels between the two groups were not significantly different (p > 0.05). GSH, AOPP, and MDA levels and the SOD activities in the diabetic senile cataract group were significantly increased as compared to the control group (p < 0.05). Oxidative stress is one of the major factors which may lead to the early cataract formation. Oxidative events are of great importance in diabetic complications and, particularly in the lens, may have a role in the pathogenesis of cataract associated with diabetes mellitus as exhibited in this study.

Antioxidative defence alterations in skeletal muscle during prolonged acclimation to cold: role ofl-arginine/NO-producing pathway

Early in cold acclimation (1-7 days), heat is produced by shivering, while late in cold acclimation (12-45 days), skeletal muscle contributes to thermogenesis by tissue metabolism other than contractions. Given that both thermogenic phases augment skeletal muscle aerobic power and reactive species production, we aimed in this study to examine possible changes in skeletal muscle antioxidative defence (AD) during early and late cold acclimation with special emphasis on the influence of the L-arginine/nitric oxide (NO)-producing pathway on the modulation of AD in this tissue. Adult Mill Hill hybrid hooded rat males were divided into two main groups: a control group, which was kept at room temperature (22+/-1 degrees C), and a group maintained at 4+/-1 degrees C for 45 days. The cold-acclimated group was divided into three subgroups: untreated, L-arginine treated and N(omega)-nitro-L-arginine methyl ester (L-NAME) treated. The AD parameters were determined in the gastrocnemius muscle on day 1, 3, 7, 12, 21 and 45 of cold acclimation. The results showed an improvement of skeletal muscle AD in both early and late cold acclimation. Clear phase-dependent changes were seen only in copper, zinc superoxide dismutase activity, which was increased in early cold acclimation but returned to the control level in late acclimation. In contrast, there were no phase-dependent changes in manganese superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase and glutathione S-transferase, the activities of which were increased during the whole cold exposure, indicating their engagement in both thermogenic phases. L-Arginine in early cold acclimation accelerated the cold-induced AD response, while in the late phase it sustained increases achieved in the early period. L-NAME affected both early and late acclimation through attenuation and a decrease in the AD response. These data strongly suggest the involvement of the L-arginine/NO pathway in the modulation of skeletal muscle AD.

Tissue zinc levels in precancerous tissue in the gastrointestinal tract of azoxymethane (AOM)-treated rats

Alterations in tissue zinc levels have been documented in patients with gastrointestinal tract malignancies and more frequently, in those with colonic cancer. However, the precise role of tissue zinc in carcinogenesis is not well elucidated. This study, using a well-established colon cancer model in rats, was designed to investigate the relationship of tissue zinc to the carcinogenic process. The aim was to examine tissue zinc levels in the preneoplastic tissues and to study the changes that occur during transition of mucosa from normal to preneoplastic state. Six-week old rats were given a single dose subcutaneous injection of azoxymethane (AOM) (30 mg/kg body weight) and sacrificed after 1, 2, 5, and 9 months of the treatment. Plasma zinc levels showed a significant decrease ( p<0.05) at 9 months compared with controls. Tissue zinc levels showed a significant decrease in the large intestine at 1 and 2 months ( p<0.05) and at 5 and 9 months ( p<0.01), in the small intestine at 2, 5, and 9 months ( p<0.05), and in the stomach at 5 and 9 months ( p<0.05). The maximum percent decrease (45%) in tissue zinc was observed in the large intestine at 9 months. Tissue copper zinc super oxide dismutase (CuZnSOD) activity was assessed in the body of the stomach, small intestine, and large intestine and compared with the control group. There was a significant fall in CuZnSOD levels in the small intestine at 9 months ( p<0.05) and in the large intestine at 5 and 9 months ( p<0.01). Two of these six rats showed histological evidence of precancerous lesions in the mucosa of the colon. This study suggests that the decrease in plasma zinc, tissue zinc and activity of CuZnSOD is associated with development of preneoplastic lesions in the colonic mucosa.

Dietary copper requirements of juvenile grouper, Epinephelus malabaricus

To quantify dietary copper (Cu) requirements in grouper, Epinephelus malabaricus, copper sulfate was added to the basal diet at 0, 1, 2, 4, 6, 8, 10 and 20 mg Cu/kg diet providing the actual dietary value of 0.11, 1.66, 2.41, 4.37, 6.56, 8.97, 11.03 and 20.05 mg Cu/kg diet, respectively. Each diet was fed to triplicate groups of grouper (initial body weight 13.35±0.01 g) in a recirculated rearing system for 8 weeks. The Cu concentration in rearing water was monitored during the feeding period and ranged from 1.0–1.5 μg/l. Weight gain (WG) and feed efficiency (FE) were higher (P<0.05) in fish fed diets with 4.37 and 6.56 mg Cu/kg diet than those in fish fed diets with ≥11.03 and ≤1.66 mg Cu/kg diet. Hepatic thiobarbituric acid reactive substances (TBARS) value was lowest in fish fed diets with 4.37 and 6.56 mg Cu/kg diet, intermediate in fish fed diets with 11.03 and ≤1.66 mg Cu/kg diet, and highest in fish fed the diet with 20.05 mg Cu/kg diet. Differences between each of the three groups were statistically significant (P<0.05). Both hepatic copper–zinc superoxide dismutase (Cu–Zn SOD) and plasma ceruloplasmin activities in fish fell into four groups. Cu–Zn SOD value was highest in fish fed the diet with 6.56 mg Cu/kg diet, second highest in fish fed the diet with 8.97 mg Cu/kg diet, intermediate in fish fed the diet with 20.05 mg Cu/kg diet, and lowest in fish fed the diet with 0.11 mg Cu/kg diet; plasma ceruloplasmin was highest in fish fed the diet with 6.56 mg Cu/kg diet, second highest in fish fed diets with 2.41, 4.37 and 8.97 mg Cu/kg diet, intermediate in fish fed diets with ≥11.03 mg Cu/kg diet, and lowest in fish fed diets with ≤1.66 mg Cu/kg diet. All values in each of the four groups were significantly different from the values of three other groups (P<0.05). Analysis by broken-line regression of WG, hepatic SOD activity and TBARS value and linear regression of whole-body Cu retention of the fish indicate that the adequate dietary Cu concentration in growing grouper is about 4–6 mg Cu/kg diet.

Sympatric Drosophila simulans flies with distinct mtDNA show age related differences in mitochondrial metabolism

The primary causes of age-related changes in mitochondrial metabolism are not known. The goal of this study is to document the influence of naturally occurring mtDNA variation on age dependent changes in mitochondrial respiration, hydrogen peroxide (H 2O 2) generation and antioxidant defenses in the fly Drosophila simulans. Possible changes include an increase in rates of reactive oxygen species production with age and/or an age dependent decrease in antioxidant response. For this study we have used flies harboring distinct siII and siIII mtDNA types. Previously we have shown that males harboring siII mtDNA had higher rates of mitochondrial H 2O 2 production from complex III at 11 d compared to males with the siIII mtDNA type. Here, we corroborate those results and show that Drosophila harboring the siII and siIII mtDNA types exhibit significantly different patterns of pro-oxidant and antioxidant activities as they age. Flies harboring siII mtDNA had higher rates of mitochondrial H 2O 2 production and manganese superoxide dismutase activity at 11 and 18 d of age than siIII mtDNA harboring flies. Copper–zinc superoxide dismutase activity increased from 11 to 25 d in siII flies while the accumulation of oxidized glutathione did not change between 11 and 25 d. In contrast, siIII harboring flies showed an age dependent increase in H 2O 2 production, reaching higher production rates on day 25 than that observed in siII flies. Copper–zinc superoxide dismutase activities did not change between 11 and 25 d while the oxidized glutathione accumulation increased with age. The results show antioxidant levels correlate with pro-oxidant levels in siII but not siIII flies. These results demonstrate our ability to correlate mtDNA variation with differences in whole mitochondrial physiology and individual complex biochemistry.

STRESS‐DEPENDENT INDUCTION OF PROTEIN OXIDATION, LIPID PEROXIDATION AND ANTI‐OXIDANTS IN PERIPHERAL TISSUES OF RATS: COMPARISON OF THREE STRESS MODELS (IMMOBILIZATION, COLD AND IMMOBILIZATION–COLD)

1. It is known that stress causes disruption of homeostasis and an imbalanced anti-oxidant status in several organs. The aim of the present study was to determine the effects of three stress models on protein oxidation, lipid peroxidation and anti-oxidant enzyme activities in the liver, kidney and heart, and to investigate the relationship between corticosterone and some oxidative stress parameters. In addition, we investigated the most effective stress model for each parameter in each tissue. 2. Thirty-six male Wistar rats (aged 3 months old, weighing 220 +/- 20 g) were divided randomly into four groups of nine rats each: control (C), immobilization stress (IS), cold stress (CS), and immobilization-cold stress (ICS). 3. Results showed that corticosterone levels were increased in all stress groups. Levels of protein carbonyl (PC), conjugated dienes (CD) and thiobarbituric acid-reactive substances (TBARS) were increased, whereas reduced glutathione (GSH) levels were decreased in all tissues of all stress groups. Copper, zinc-superoxide dismutase (Cu,Zn-SOD) activities were increased in the liver and kidney of all stress groups, but were decreased in heart of the IS and CS groups. Catalase (CAT) activities were increased in liver of the CS group and in kidney and heart of all stress groups, but were decreased in liver of the IS and ICS groups. Selenium-dependent glutathione peroxidase (Se-GSH-Px) activities were increased in liver of the CS and ICS groups and in heart of all stress groups, but were decreased in kidney of the IS group. Also, Se-GSH-Px activity levels remained unchanged in liver of the IS group and in kidney of the CS and ICS groups. The increased CAT activity and unchanged Se-GSH-Px activity observed in kidney suggest that H2O2 may be primarily scavenged by CAT. 4. The strong correlations between corticosterone and oxidative damage markers (e.g. protein oxidation, lipid peroxidation and GSH levels) suggest a relationship between these parameters. Liver was affected most by the CS model, whereas kidney and heart were affected most by ICS model. Stress-induced changes in the activities of anti-oxidant enzymes and GSH levels were found to be tissue- and enzyme-specific. In conclusion, results of the present study suggest that each stress model affects the different organ tissues in different ways.

Vitamin A deficiency induces prooxidant environment and inflammation in rat aorta

We evaluated whether nutritional vitamin A deficiency generates oxidative stress and inflammation in aorta. Wistar male rats (21 days old) were given free access to a control (8 mg retinol as retinyl palmitate/kg) or a vitamin A- deficient diet for three months. One group of deficient animals was fed with the control diet fifteen days before sacrifice. Thiobarbituric acid-reactive substances (TBARS) and nitrite concentration where both analyzed in serum and aorta. Aorta Copper–Zinc Superoxide dismutase (CuZnSOD), Glutathion peroxidase (GPx) and Catalase (CAT) activities were measured. In addition, binding activity of the nuclear factor- kB (NF-kB), inducible and endothelial Nitric Oxide synthase (iNOS and eNOS, respectively) and Ciclooxygenase-2 (COX-2) expressions were determinated in aorta. Rats fed the vitamin A- deficient diet were characterized by sub-clinical plasma retinol concentration and showed increased serum and aorta concentrations of TBARS compared to controls. Lower than control activities of CuZnSOD, GPx, and CAT were observed in aorta of the vitamin A- deficient group. The binding activity of NF- kB was higher in vitamin A- deficient animals than controls. In addition, NO production evaluated as nitrite concentration increased in aorta and serum, associated with a higher expression of iNOS, eNOS and COX-2 in aorta of vitamin A-deficient rats. The incorporation of vitamin A into the diet of vitamin A-deficient rats reverted the changes observed in TBARS level, CuZnSOD and GPx activities, nitrite concentration and also, iNOS, eNOS and COX-2 expression. Prooxidant environment and inflammation are induced by vitamin A deficiency in rat aorta.

Diabetes and dietary copper alter 67Cu metabolism and oxidant defense in the rat

Perturbations in copper (Cu) metabolism are a characteristic of diabetes, for example, elevated plasma Cu and compromised oxidant defense related to diabetes-induced effects on Cu-containing enzymes. Herein, the redistribution of Cu in selected tissues is described in response to diabetic and nondiabetic states in rats that were fed diets adequate in (12 mg Cu/kg of diet) or deficient in (no added Cu) Cu. Diabetes was induced by intravenous administration of streptozotocin (40 mg/kg body weight). After 5 weeks, rats were gavaged with 67Cu (0.74 MBq per rat) using the Cu-deficient diet as a vehicle (suspended 1:3 in water) and killed at various time points. The use of 67Cu allowed for the assessment of short-term Cu distribution and its comparison to the steady-state Cu distribution, as determined by direct Cu analysis. In contrast to control rats, the adaptive mechanisms for Cu homeostasis in diabetic rats were impaired. In general, measures of Cu retention were reduced in diabetic rats compared to corresponding values for control rats. Moreover, diabetic rats had low copper, zinc superoxide dismutase activity that was reduced even further when diabetic rats were fed with low-Cu diets. However, liver and kidney metallothionein and plasma ceruloplasmin levels were elevated in diabetic rats compared to control rats. Such diabetes-related metabolic alterations were taken as measures of increased oxidative stress and inflammation, which may have implications in the progression of diabetes-related pathologies.

Copper–zinc superoxide dismutase activity in healthy and inflamed human dental pulp

To examine copper-zinc superoxide dismutase (Cu, Zn-SOD) activity in clinically healthy and symptomatic human dental pulps. Twenty-five systemically healthy patients, 14 females and 11 males (age: 13.1-34.6 years; mean: 21.7 +/- 6.3), were the source of the pulp tissue. The condition of the pulps was assessed using clinical and radiographic evaluation. The pulp tissue was collected by longitudinally grooving and splitting the teeth (if extracted) or during endodontic treatment, and were age- and sex-matched between the healthy and the irreversible symptomatic pulpitis tissue groups. Cu, Zn-SOD activity was determined through spectrophotometric methods and a Mann-Whitney test assessed the significance of differences between the groups. The enzyme activities were 144.8 +/- 42.2 and 68.1 +/- 25.0 U mg(-1) in the healthy and irreversible symptomatic pulp tissue, respectively. The difference between the groups was statistically significant (P < 0.001). These results demonstrate a potential role for Cu, Zn-SOD during dental pulp inflammation in humans.

Plasma Lipid Peroxidation Zinc And Erythrocyte Cu-Zn Superoxide Dismutase Enzyme Activity In Patients With Type 2 Diabetes Mellitus In Gorgan City (South East Of The Caspian Sea)

The aim of this study was to determine the changes of plasma lipid peroxidation, zinc and erythrocyte Cu-Zn superoxide dismutase activity in patients with type 2 diabetes mellitus and healthy control in Gorgan city. Fifty type 2 patients with diabetes mellitus and 50 people without diabetes were included in this randomized study. None of patients studied had any diabetic complications. The levels of plasma malondialdehyde and zinc from type 2 diabetes mellitus patients (6.24±0.85 nmol mL-1 and 116.78±5.51 μ dL-1) and control groups (3.63±0.97 nmol mL-1 and 146.86±9.06 μg dL-1) were determined. Erythrocyte Cu-Zn superoxide dismutase activity from patients with diabetes (675.34±60.89 U g-1 Hb) and control groups (1052.70± 52.76 U g-1 Hb) were determined. The increased plasma lipid peroxidation and decreased plasma zinc and erythrocyte Cu-Zn superoxide dismutase activity that we observed in patients with type 2 diabetes mellitus may predispose to the development of cardiovascular complications. We propose that diabetic patients may have elevated requirement for antioxidants. Supplementation with zinc and vitamin or dietary free radical scavengers such as vitamins E and C or tomato, orange and etc. have a potential role in boosting antioxidant-related defences and maybe important in patients with diabetes.

Alterations in brain antioxidant status, protein oxidation and lipid peroxidation in response to different stress models

The aim of this study was to investigate the effects of different stress models on copper, zinc-superoxide dismutase (Cu,Zn-SOD), catalase (CAT) and selenium-dependent glutathione peroxidase (Se-GSH-Px) activities, and reduced glutathione (GSH), protein carbonyl (PC) and lipid peroxidation marker (conjugated diene (CD) and thiobarbituric acid-reactive substances (TBARS)) levels in brain of rats, and to determine the most effective stress model according to each parameter. Rats were divided into four groups as following: control group (C), immobilization stress group (IS), cold stress group (CS) and immobilization–cold stress group (ICS). All stress models increased brain Cu,Zn-SOD and CAT activities, PC, CD and TBARS levels, plasma corticosterone levels and decreased brain GSH concentrations. Se-GSH-Px activity was increased in CS and ICS groups. When all stress models were taken into consideration, the highest increases in Cu,Zn-SOD and Se-GSH-Px activities were found in CS group. The lowest GSH level was seen in IS group. The highest increases in PC and TBARS levels were found in ICS group. The highest increase of CD concentration was seen in IS and ICS groups. Our results suggest that different stress models have different degrees of influences on enzymatic and non-enzymatic antioxidant defense systems, protein oxidation and lipid peroxidation in the brain.

Cold-stress-induced modulation of antioxidant defence: role of stressed conditions in tissue injury followed by protein oxidation and lipid peroxidation.

The aim of this study was to determine the effects of cold stress on antioxidant enzyme activities and examine protein oxidation and lipid peroxidation in various tissues (brain, liver, kidney, heart and stomach). Twenty male Wistar rats (3 months old) weighing 220 +/- 20 g were used. The rats were randomly divided into two groups of ten: the control group and the cold stress group. Cold stress was applied to the animals by maintaining them in a cold room (5 degrees C) for 15 min/day for 15 days. Blood samples were taken for measuring plasma corticosterone levels. Tissues were obtained from each rat for measuring the antioxidant enzyme activities, protein oxidation and lipid peroxidation. Corticosterone levels were increased in the cold stress group. Copper, zinc superoxide dismutase activities were increased in the brains, livers and kidneys, whereas they decreased in the hearts and stomachs of rats in the cold stress group. Catalase activities were increased in the brains, livers, kidneys and hearts, whereas they decreased in the stomachs of rats in the cold stress group. Selenium-dependent glutathione peroxidase activities were increased in the brain, liver, heart and stomach. Reduced glutathione levels were decreased, while levels of protein carbonyl, conjugated diene and thiobarbituric-acid-reactive substances were increased in all tissues of the cold stress group. These results lead us to conclude that cold stress can disrupt the balance in an oxidant/antioxidant system and cause oxidative damage to several tissues by altering the enzymatic and non-enzymatic antioxidant status, protein oxidation and lipid peroxidation.

Iron supplementation in experimental hyperthyroidism: effects on oxidative stress in skeletal muscle tissue.

This study was designed to investigate the effects of iron supplementation on the parameters of oxidative stress in the skeletal muscle tissue of hyperthyroidism induced rats. Hyperthyroidism was found to cause an increase in thiobarbituric acid-reactive substances (TBARS) and copper zinc superoxide dismutase (Cu, Zn SOD) activity, but decreases in the glutathione-peroxidase (GSH Px) activity and glutathione (GSH). Iron supplementation caused an increase in TBARS and a decrease in GSH. Iron supplementation in hyperthyroid rats attenuated the hyperthyroid state, but lowered the plasma ferritin level, which is considered an indicator of thyroid hormone action. Iron supplementation caused no additional increase in the TBARS in hyperthyroid rats, ameliorated the decrease in GSH content and abolished the induction of Cu, Zn SOD. Our findings suggested no increase, but a decrease, in the risk of oxidative stress in iron supplemented hyperthyroid rats. Whether supplementation of iron would have similar effects in humans should be further investigated in clinical studies.

Changes in glucose-6-phosphate dehydrogenase, copper, zinc-superoxide dismutase and catalase activities, glutathione and its metabolizing enzymes, and lipid peroxidation in rat erythrocytes with age

We have studied the activities of enzymes (glucose-6-phosphate dehydrogenase (G-6-PD), copper, zinc-superoxide dismutase (Cu,Zn-SOD), catalase (CAT), selenium-dependent glutathione peroxidase (Se-GSH-Px) and glutathione-S-transferase (GST)), and the levels of reduced glutathione (GSH), oxidized glutathione (GSSG) and thiobarbituric acid-reactive substances (TBARS) in rat erythrocytes and estimated the ratio of GSH/GSSG and the redox index. Male Wistar rats at ages of 1, 6 and 12 months were used. The activities of G-6-PD and Cu,Zn-SOD, the levels of GSSG and TBARS were increased, while the activity of Se-GSH-Px and the level of GSH were decreased with age. GSH/GSSG ratio was significantly decreased with age. We found a positive correlation between age and G-6-PD (r=0.476, p<0.01), Cu,Zn-SOD (r=0.291, p<0.01), CAT (r=0.254, p<0.01) and GST activities (r=0.250, p<0.05), and GSSG (r=0.708, p<0.05) and TBARS levels (r=0.802, p<0.01), whereas the correlation between age and Se-GSH-Px activity (r=−0.376, p<0.05), GSH level (r=−0.603, p<0.01) and GSH/GSSG ratio (r=−0.685, p<0.05) were negative. We found age-related differences in erythrocyte antioxidant enzyme activities, GSH, GSSG, total GSH and TBARS levels, GSH/GSSG ratio and the redox index.

Carbohydrate metabolism in erythrocytes of copper deficient rats

Dietary copper deficiency is known to adversely affect the circulatory system of fructose-fed rats. Part of the problem may lie in the effect of copper deficiency on intermediary metabolism. To test this, weanling male Long-Evans rats were fed for 4 or 8 weeks on sucrose-based diets containing low or adequate copper content. Copper deficient rats had significantly lower plasma and tissue copper as well as lower plasma copper, zinc-superoxide dismutase activity. Copper deficient rats also had a significantly higher heart:body weight ratio when compared to pair-fed controls. Direct measurement of glycolysis and pentose phosphate pathway flux in erythrocytes using 13C NMR showed no differences in carbon flux from glucose or fructose to pyruvate but a significantly higher flux through the lactate dehydrogenase locus in copper deficient rats (approximately 1.3 times, average of glucose and glucose + fructose measurements). Copper-deficient animals had significantly higher erythrocyte concentrations of glucose, fructose, glyceraldehyde 3-phosphate and NAD +. Liver metabolite levels were also affected by copper deficiency being elevated in glycogen and fructose 1-phosphate content. The results show small changes in carbohydrate metabolism of copper deficient rats.

Kinetics of wound-induced activation of antioxidative enzymes in Oryza sativa: differential activation at different growth stages

Superoxide dismutase, peroxidase and catalase are major antioxidative enzymes that contribute to the oxidative stress response in plants. The activity of these enzymes was measured in wound-stressed rice plants that were wounded at seedling stage, maximum tillering stage or flowering stage. Kinetics of enzyme activity were examined in leaf extracts post-wounding. Superoxide dismutase activity increased rapidly until 6 h after wounding and was maintained at a high level throughout development. Wound stress-induced changes in manganese superoxide dismutase and copper–zinc superoxide dismutase activities were detected using a native activity gel. In contrast, catalase was rapidly deactivated and peroxidase was transiently activated and then deactivated after wounding. However, high peroxidase activity was maintained at maximum tillering stage of development. These observations suggest that rice antioxidant enzymes are differentially activated by wound stress depending on the plant growth stage, and that the antioxidative enzymes are activated by wounding in two phases. The first phase involves activation of superoxide dismutase and peroxidase and rapid deactivation of catalase. The second phase involves deactivation of peroxidase under conditions of severe stress. Deactivation of peroxidase and catalase may lead to accumulation of hydrogen peroxide, which can activate of a series of additional defense mechanisms.

Changes in somatosensory evoked potentials, lipid peroxidation, and antioxidant enzymes in experimental diabetes: effect of sulfur dioxide.

The effect of sulfur dioxide (SO2) on brain antioxidant status, lipid peroxidation, and somatosensory evoked potentials (SEPs) was investigated in diabetic rats. A total of 40 rats were divided into 4 equal groups: control (C), SO2 + C (SO2), diabetic (D), and SO2 + D (DSO2). Experimental diabetes mellitus was induced by i.v. injection of alloxan at a dose of 50 mg/kg body weight. Ten ppm SO2 was administered to the rats in the sulfur dioxide groups (SO2 and DSO2) in an exposure chamber. Exposure occurred 1 hr/day, 7 days/wk, for 6 wk; control rats were exposed to filtered air during the same time periods. Although SO2 exposure markedly increased copper, zinc Superoxide dismutase activity, it significantly decreased glutathione peroxidase activity in both the diabetic and nondiabetic groups, compared with the C group. Brain catalase activity was unaltered; however, brain thiobarbituric acid reactive substances (TBARS) were elevated in all experimental groups with respect to the C group. SEP components P1, N1, P2, and N2 were significantly increased in all experimental groups, compared with the C group, and these components were also prolonged in the DSO2 group with respect to the other groups. The authors' findings suggest that exposure to SO2, because it increases lipid peroxidation, can change antioxidant enzyme activities and affect SEP components in diabetic rats.

Ctr6, a Vacuolar Membrane Copper Transporter inSchizosaccharomyces pombe

Aerobic organisms possess efficient systems for the transport of copper. This involves transporters that mediate the passage of copper across biological membranes to reach essential intracellular copper-requiring enzymes. In this report, we identify a new copper transporter in Schizosaccharomyces pombe, encoded by the ctr6(+) gene. The transcription of ctr6(+) is induced under copper-limiting conditions. This regulation is mediated by the cis-acting promoter element CuSE (copper-signaling element) through the copper-sensing transcription factor Cuf1. An S. pombe strain bearing a disrupted ctr6Delta allele displays a strong reduction of copper,zinc superoxide dismutase activity. When the ctr6+ gene is overexpressed from the thiamine-inducible nmt1(+) promoter, the cells are unable to grow on medium containing exogenous copper. Surprisingly, this copper-sensitive growth phenotype is not due to an increase of copper uptake at the cell surface. Instead, copper delivery across the plasma membrane is reduced. Consistently, this results in repressing ctr4(+) gene expression. By using a functional ctr6(+) epitope-tagged allele expressed under the control of its own promoter, we localize the Ctr6 protein on the membrane of vacuoles. Furthermore, we demonstrate that Ctr6 is an integral membrane protein that can trimerize. Moreover, we show that Ctr6 harbors a putative copper-binding Met-X-His-Cys-X-Met-X-Met motif in the amino terminus, which is essential for its function. Our findings suggest that under conditions in which copper is scarce, Ctr6 is required as a means to mobilize stored copper from the vacuole to the cytosol.

Increased oxidative stress and hypozincemia in male obesity

Objectives Antioxidants protect an organism from the detrimental effects of free radicals via scavenging or inhibiting their formation. Alterations in the levels of antioxidants and several essential trace elements in the plasma and various tissues of ob/ob mice have been reported previously. The aim of this study was to investigate oxidative status and trace elements in obese individuals. Design and methods Seventy-six obese men (body mass index (BMI) > 30 kg/m 2) and 24 healthy, age-matched male control volunteers were enrolled in the study. Fasting plasma insulin, glucose, triglyceride (TG), total cholesterol, VLDL, and HDL levels, erythrocyte glutathione peroxidase (GSH-Px) and copper zinc-superoxide dismutase (CuZn-SOD) activities, and erythrocyte thiobarbituric acid reactive substances (TBARS) levels were measured in both groups. Erythrocyte copper (Cu), zinc (Zn) and iron (Fe) levels were also measured. Results We found that the mean Cu and Fe levels in obese individuals were not significantly different than those in the control group, whereas the mean Zn levels were significantly lower than those of the control group ( p = 0.023). The mean erythrocyte CuZn-SOD and GSH-Px levels in obese individuals were significantly lower than those in controls ( p = 0.001) whereas erythrocyte TBARS levels were significantly higher ( p = 0.001) than those of the control group. Conclusion We conclude that male obesity is associated with defective antioxidant status and hypozincemia, which may have implications in the development of obesity related health problems.

Red blood cell copper, zinc superoxide dismutase activity is higher in Alzheimer's disease and is decreased by d-penicillamine

Copper, zinc superoxide dismutase (Cu, Zn SOD) activity was measured in red blood cells (RBC) of 32 patients affected by Alzheimer's disease (AD), eight other AD patients treated with the copper-chelating agent d-penicillamine, 13 first-degree relatives and 22 controls. All AD patients enrolled in our study showed a higher level of Cu, Zn SOD activity early in the disease. No correlation between apolipoprotein E genotype and SOD activity was found in AD patients. d-penicillamine treatment of AD patients for 24 weeks lowered the enzyme activity even below the control value. These results support the hypothesis that a higher level of Cu, Zn SOD activity in RBC can be an early diagnostic peripheral marker of this disease and a sensor to monitor treatments with copper-chelating drugs.