The Roles of Glutathione Peroxidases during Embryo Development.

Science.gov (United States)

Ufer, Christoph; Wang, Chi Chiu

2011-01-01

Embryo development relies on the complex interplay of the basic cellular processes including proliferation, differentiation, and apoptotic cell death. Precise regulation of these events is the basis for the establishment of embryonic structures and the organ development. Beginning with fertilization of the oocyte until delivery the developing embryo encounters changing environmental conditions such as varying levels of oxygen, which can give rise to reactive oxygen species (ROS). These challenges are met by the embryo with metabolic adaptations and by an array of anti-oxidative mechanisms. ROS can be deleterious by modifying biological molecules including lipids, proteins, and nucleic acids and may induce abnormal development or even embryonic lethality. On the other hand ROS are vital players of various signaling cascades that affect the balance between cell growth, differentiation, and death. An imbalance or dysregulation of these biological processes may generate cells with abnormal growth and is therefore potentially teratogenic and tumorigenic. Thus, a precise balance between processes generating ROS and those decomposing ROS is critical for normal embryo development. One tier of the cellular protective system against ROS constitutes the family of selenium-dependent glutathione peroxidases (GPx). These enzymes reduce hydroperoxides to the corresponding alcohols at the expense of reduced glutathione. Of special interest within this protein family is the moonlighting enzyme glutathione peroxidase 4 (Gpx4). This enzyme is a scavenger of lipophilic hydroperoxides on one hand, but on the other hand can be transformed into an enzymatically inactive cellular structural component. GPx4 deficiency - in contrast to all other GPx family members - leads to abnormal embryo development and finally produces a lethal phenotype in mice. This review is aimed at summarizing the current knowledge on GPx isoforms during embryo development and tumor development with an emphasis on

Sex determines the influence of smoking and gene polymorphism on glutathione peroxidase activity in erythrocytes

DEFF Research Database (Denmark)

Malling, Tine Halsen; Sigsgaard, Torben; Andersen, Helle Raun

2009-01-01

OBJECTIVE: Glutathione peroxidase 1 (GPX1) is one of the major oxidative enzymes. Our aim was to characterize factors influencing its activity and to determine whether or not the activity is associated with asthma. MATERIAL AND METHODS: Serum selenium concentration was measured, GPX1 polymorphisms...... %) had doctor-diagnosed asthma. RESULTS: The average serum selenium concentration was too low for optimal enzyme activity (mean (SE), 83.4 (0.76) ng/mL). GPX1 activity in men was lower than in women, 52.6 (0.66) and 56.4 (0.59) U/g protein, respectively (p... associated with serum selenium concentration (p = 0.005) and negatively associated with both active smoking (p = 0.009) and exposure to environmental tobacco smoke (p = 0.02). In women, activity was associated with genotypes with 59.2 (1.4), 56.0 (1.4) and 54.2 (1.4) U/g protein in the homozygote wild...

A selenium-deficient Caco-2 cell model for assessing differential incorporation of chemical or food selenium into glutathione peroxidase.

Science.gov (United States)

Zeng, Huawei; Botnen, James H; Johnson, Luann K

2008-01-01

Assessing the ability of a selenium (Se) sample to induce cellular glutathione peroxidase (GPx) activity in Se-deficient animals is the most commonly used method to determine Se bioavailability. Our goal is to establish a Se-deficient cell culture model with differential incorporation of Se chemical forms into GPx, which may complement the in vivo studies. In the present study, we developed a Se-deficient Caco-2 cell model with a serum gradual reduction method. It is well recognized that selenomethionine (SeMet) is the major nutritional source of Se; therefore, SeMet, selenite, or methylselenocysteine (SeMSC) was added to cell culture media with different concentrations and treatment time points. We found that selenite and SeMSC induced GPx more rapidly than SeMet. However, SeMet was better retained as it is incorporated into proteins in place of methionine; compared with 8-, 24-, or 48-h treatment, 72-h Se treatment was a more sensitive time point to measure the potential of GPx induction in all tested concentrations. Based on induction of GPx activity, the cellular bioavailability of Se from an extract of selenobroccoli after a simulated gastrointestinal digestion was comparable with that of SeMSC and SeMet. These in vitro data are, for the first time, consistent with previous published data regarding selenite and SeMet bioavailability in animal models and Se chemical speciation studies with broccoli. Thus, Se-deficient Caco-2 cell model with differential incorporation of chemical or food forms of Se into GPx provides a new tool to study the cellular mechanisms of Se bioavailability.

Hepatic and erythrocytic glutathione peroxidase activity in liver diseases.

Science.gov (United States)

Cordero, R; Ortiz, A; Hernández, R; López, V; Gómez, M M; Mena, P

1996-09-01

Hepatic and erythrocytic glutathione peroxidase activity, together with malondialdehyde levels, were determined as indicators of peroxidation in 83 patients from whom liver biopsies had been taken for diagnostic purposes. On histological study, the patients were classified into groups as minimal changes (including normal liver), steatosis, alcoholic hepatitis, hepatic cirrhosis, light to moderately active chronic hepatitis, and severe chronic active hepatitis. The glutathione peroxidase activity in erythrocytes showed no significant changes in any liver disease group. In the hepatic study, an increased activity was observed in steatosis with respect to the minimal changes group, this increased activity induced by the toxic agent in the initial stages of the alcoholic hepatic disease declining as the hepatic damage progressed. There was a negative correlation between the levels of hepatic malondialdehyde and hepatic glutathione peroxidase in subjects with minimal changes. This suggested the existence of an oxidative equilibrium in this group. This equilibrium is broken in the liver disease groups as was manifest in a positive correlation between malondialdehyde and glutathione peroxidase activity.

Novel interaction of diethyldithiocarbamate with the glutathione/glutathione peroxidase system

International Nuclear Information System (INIS)

Kumar, K.S.; Sancho, A.M.; Weiss, J.F.

1986-01-01

Diethyldithiocarbamate (DDC) exhibits a variety of pharmacologic activities, including both radioprotective and sensitizing properties. Since the glutathione/glutathione peroxidase system may be a significant factor in determining radiation sensitivity, the potential mechanisms of action of DDC in relation to this system were examined in vitro. The interaction of DDC with reduced glutathione (GSH) was tested using a simple system based on the reduction of cytochrome c. When DDC (0.005 mM) was incubated with GSH (0.5 mM), the reduction of cytochrome c was eightfold greater than that expected from an additive effect of DDC and GSH. GSH could be replaced by oxidized glutathione and glutathione reductase. Cytochrome c reduced by DDC was oxidized by mitochondria. The interaction of DDC with both the hexosemonophosphate shunt pathway and the mitochondrial respiratory chain suggests the possibility of linking these two pathways through DDC. Oxidation of DDC by peroxide and reversal by GSH indicated that the drug can engage in a cyclic reaction with peroxide and GSH. This was confirmed when DDC was used in the assay system for glutathione peroxidase (GSHPx) without GSHPx. DDC at a concentration of 0.25 mM was more active than 0.01 unit of pure GSHPx in eliminating peroxide, and much more active than the other sulfhydryl compounds tested. These studies indicate that DDC can supplement GSHPx activity or substitute for it in detoxifying peroxides, and suggests a unique role in the chemical modification of radiation sensitivity

EURRECA—Estimating Selenium Requirements for Deriving Dietary Reference Values

NARCIS (Netherlands)

Hurst, R.; Collings, R.; Harvey, L.J.; King, M.; Hooper, L.; Bouwman, J.; Gurinovic, M.; Fairweather-Tait, S.J.

2013-01-01

Current reference values for selenium, an essential micronutrient, are based on the intake of selenium that is required to achieve maximal glutathione peroxidase activity in plasma or erythrocytes. In order to assess the evidence of relevance to setting dietary reference values for selenium, the

Loss of Selenium-Binding Protein 1 Decreases Sensitivity to Clastogens and Intracellular Selenium Content in HeLa Cells.

Science.gov (United States)

Zhao, Changhui; Zeng, Huawei; Wu, Ryan T Y; Cheng, Wen-Hsing

2016-01-01

Selenium-binding protein 1 (SBP1) is not a selenoprotein but structurally binds selenium. Loss of SBP1 during carcinogenesis usually predicts poor prognosis. Because genome instability is a hallmark of cancer, we hypothesize that SBP1 sequesters cellular selenium and sensitizes cancer cells to DNA-damaging agents. To test this hypothesis, we knocked down SBP1 expression in HeLa cervical cancer cells by employing a short hairpin RNA (shRNA) approach. Reduced sensitivity to hydrogen peroxide, paraquat and camptothecin, reactive oxygen species content, and intracellular retention of selenium after selenomethionine treatment were observed in SBP1 shRNA HeLa cells. Results from Western analyses showed that treatment of HeLa cells with selenomethionine resulted in increased SBP1 protein expression in a dose-dependent manner. Knockdown of SBP1 rendered HeLa cells increased expression of glutathione peroxidase-1 but not glutathione peroxidase-4 protein levels and accelerated migration from a wound. Altogether, SBP1 retains supplemental selenium and sensitizes HeLa cancer cells to clastogens, suggesting a new cancer treatment strategy by sequestering selenium through SBP1.

Molecular consequences of genetic variations in the glutathione peroxidase 1 selenoenzyme.

Science.gov (United States)

Zhuo, Pin; Goldberg, Marci; Herman, Lauren; Lee, Bao-Shiang; Wang, Hengbing; Brown, Rhonda L; Foster, Charles B; Peters, Ulrike; Diamond, Alan M

2009-10-15

Accumulating data have implicated the selenium-containing cytosolic glutathione peroxidase, GPx-1, as a determinant of cancer risk and a mediator of the chemopreventive properties of selenium. Genetic variants of GPx-1 have been shown to be associated with cancer risk for several types of malignancies. To investigate the relationship between GPx-1 enzyme activity and genotype, we measured GPx-1 enzyme activity and protein levels in human lymphocytes as a function of the presence of two common variations: a leucine/proline polymorphism at codon 198 and a variable number of alanine-repeat codons. Differences in GPx activity among these cell lines, as well as in the response to the low-level supplementation of the media with selenium, indicated that factors other than just genotype are significant in determining activity. To restrict the study to genotypic effects, human MCF-7 cells were engineered to exclusively express allelic variants representing a combination of either a codon 198 leucine or proline and either 5 or 7 alanine-repeat codons following transfection of GPx-1 expression constructs. Transfectants were selected and analyzed for GPx-1 enzyme activity and protein levels. GPx-1 with 5 alanines and a leucine at codon 198 showed a significantly higher induction when cells were incubated with selenium and showed a distinct pattern of thermal denaturation as compared with GPx-1 encoded by the other examined alleles. The collective data obtained using both lymphocytes and MCF-7 indicate that both intrinsic and extrinsic factors cooperate to ultimately determine the levels of this enzyme available to protect cells against DNA damage and mutagenesis.

Effect of selenium supplementation on pigeon reproductive performance, selenium concentration and antioxidant status.

Science.gov (United States)

Wang, Y; Yang, H M; Cao, W; Li, Y B

2017-09-01

The effects of dietary supplementation of sodium selenite (SS) on the reproductive performance and the concentration of selenium, glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), and malondialdehyde (MDA) were determined, and expression of glutathione peroxidase 4 (GPx4) and bone morphogenic protein 15 (BMP15) was evaluated. Paired pigeons (n = 864) were fed: T1 received no SS, while T2, T3, and T4 received 0.5, 1.0, and 1.5 mg of SS/kg of dry matter (DM), respectively. Treatments were performed in triplicate with 72 pairs in each replicate. The results showed that selenium supplementation significantly affected pigeon reproductive performance. Birds fed 1.0 mg of SS/kg displayed higher egg production (P > 0.05), higher birth rate, and lower dead sperm rate than the control group (P Selenium and biochemical analyses revealed a higher selenium concentration in the 1.5 mg of SS/kg group than in the control group (P  0.05); however, in plasma, MDA was lower in the control group (P  0.05), while in ovary, BMP15 was down-regulated in the 1.5 mg of SS/kg group (P selenium concentration, and 0.5 mg of SS/kg up-regulated GSH-Px activity. © 2017 Poultry Science Association Inc.

Reproduction in eastern screech-owls fed selenium

Science.gov (United States)

Wiemeyer, Stanley N.; Hoffman, D.J.

1996-01-01

Raptors are occasionally exposed to excessive selenium from contaminated prey, but the effects of this exposure on reproduction are unknown. Therefore, we fed captive eastern screech-owls (Otus asio) diets containing 0, 4.4, or 13.2 ppm (wet wt) added selenium in the form of seleno-DL-methionine. Adult mass at sacrifice and reproductive success of birds receiving 13.2 ppm selenium were depressed (P biochemistries indicative of oxidative stress were affected (P < 0.05) in 5-day-old nestlings from parents fed 4.4 ppm selenium and included a 19% increase in glutathione peroxidase activity, a 43% increase in the ratio of oxidized glutathione (GSSG) to reduced glutathione (GSH), and a 17% increase in lipid peroxidation. Based on reproductive effects relative to dietary exposure, sensitivity of eastern screech-owls to selenium was similar to that of black-crowned night-herons (Nycticorax nycticorax) but less than that of mallards (Anas platyrhynchos).

Low blood selenium: A probable factor in essential hypertension ...

African Journals Online (AJOL)

Blood selenium (BSe) and plasma glutathione peroxidase (plGSH-Px) activity were measured as biochemical markers of selenium status of 103 hypertensive patients (44 males and 59 females) and 88 apparently healthy subjects (40 males and 48 females). The hypertensive patients were classified into three groups based ...

High-Resolution Imaging of Selenium in Kidneys: A Localized Selenium Pool Associated with Glutathione Peroxidase 3

OpenAIRE

Malinouski, Mikalai; Kehr, Sebastian; Finney, Lydia; Vogt, Stefan; Carlson, Bradley A.; Seravalli, Javier; Jin, Richard; Handy, Diane E.; Park, Thomas J.; Loscalzo, Joseph; Hatfield, Dolph L.; Gladyshev, Vadim N.

2012-01-01

Aim: Recent advances in quantitative methods and sensitive imaging techniques of trace elements provide opportunities to uncover and explain their biological roles. In particular, the distribution of selenium in tissues and cells under both physiological and pathological conditions remains unknown. In this work, we applied high-resolution synchrotron X-ray fluorescence microscopy (XFM) to map selenium distribution in mouse liver and kidney. Results: Liver showed a uniform selenium distributio...

Dietary incorporation of feedstuffs naturally high in organic selenium for racing pigeons (Columba livia): effects on plasma antioxidant markers after a standardised simulation of a flying effort.

Science.gov (United States)

Schoonheere, N; Dotreppe, O; Pincemail, J; Istasse, L; Hornick, J L

2009-06-01

Selenium is a trace element of importance for animal health. It is essential for adequate functioning of many enzymes such as, the antioxidant enzyme, glutathione peroxidase, which protects the cell against free radicals. A muscular effort induces a rise in reactive oxygen species production which, in turn, can generate an oxidative stress. Two groups of eight racing pigeons were fed respectively with a diet containing 30.3 (control group) and 195.3 (selenium group) microg selenium/kg diet. The pigeons were submitted to a standardised simulation of a flying effort during 2 h. Blood was taken before and after the effort to measure antioxidant markers and blood parameters related to muscle metabolism. Plasma selenium concentration and glutathione peroxidase activity were significantly higher in the selenium group. There were no significant differences for the other measured parameters. As a consequence of the effort, the pigeons of the selenium group showed a higher increase of glutathione peroxidase activity and a smaller increase of plasma lactate concentration. Variations because of the effort in the other markers were not significantly different between the two groups. It is concluded that the selenium status was improved with the feeding of feedstuffs high in Selenium.

New scientific challenges - the possibilities of using selenium in poultry nutrition and impact on meat quality

Science.gov (United States)

Marković, R.; Glišić, M.; Bošković, M.; Baltić, M. Ž.

2017-09-01

Physiological stress is one of many concerns facing modern broiler production. In conditions when birds are exposed to stress, supplementation of selenium, which is a crucial glutathione peroxidase enzymatic cofactor, increases the antioxidant capacity of the animals and decreases the harmful effects of free radicals. Dietary selenium improves production performance and health of animals, and positively affects the immune system, the quality, selenium content and fatty acid composition of meat and eggs. There are several different forms of selenium, the most common dietary supplements being an inorganic form (sodium selenite) and anorganic form (selenomethionine). However, in recent years, new forms of selenium, such as a 2-hydroxy-4-methylselenobutanoic acid (HMSeBA) and nanoselenium, which have more bioavailability, bioefficacy, and low toxicity have been designed. In this short comparative overview discusses the effects of inorganic, organic and nanoforms of selenium on production results, glutathione peroxidase activity, meat quality and level of toxicity in poultry.

Neutron activation analysis applied to the determination of selenium in bovine plasma

International Nuclear Information System (INIS)

Hevia, Sonia E.; Resnizky, Sara M.; Gil, Susana B.; Pawlak, Eva

1999-01-01

The procedure used to determine selenium in bovine plasma by neutron irradiation of the samples, followed by a radiochemical separation, is described. This procedure allows the direct determination of the value of the selenium plasmatic level, instead of the indirect conventional method that determines the blood glutathion peroxidase enzyme, as an indicator of the selenium content in the blood. (author)

Deletion of glutathione peroxidase-2 inhibits azoxymethane-induced colon cancer development.

Directory of Open Access Journals (Sweden)

Mike F Müller

Full Text Available The selenoprotein glutathione peroxidase-2 (GPx2 appears to have a dual role in carcinogenesis. While it protected mice from colon cancer in a model of inflammation-triggered carcinogenesis (azoxymethane and dextran sodium sulfate treatment, it promoted growth of xenografted tumor cells. Therefore, we analyzed the effect of GPx2 in a mouse model mimicking sporadic colorectal cancer (azoxymethane-treatment only. GPx2-knockout (KO and wild-type (WT mice were adjusted to an either marginally deficient (-Se, adequate (+Se, or supranutritional (++Se selenium status and were treated six times with azoxymethane (AOM to induce tumor development. In the -Se and ++Se groups, the number of tumors was significantly lower in GPx2-KO than in respective WT mice. On the +Se diet, the number of dysplastic crypts was reduced in GPx2-KO mice. This may be explained by more basal and AOM-induced apoptotic cell death in GPx2-KO mice that eliminates damaged or pre-malignant epithelial cells. In WT dysplastic crypts GPx2 was up-regulated in comparison to normal crypts which might be an attempt to suppress apoptosis. In contrast, in the +Se groups tumor numbers were similar in both genotypes but tumor size was larger in GPx2-KO mice. The latter was associated with an inflammatory and tumor-promoting environment as obvious from infiltrated inflammatory cells in the intestinal mucosa of GPx2-KO mice even without any treatment and characterized as low-grade inflammation. In WT mice the number of tumors tended to be lowest in +Se compared to -Se and ++Se feeding indicating that selenium might delay tumorigenesis only in the adequate status. In conclusion, the role of GPx2 and presumably also of selenium depends on the cancer stage and obviously on the involvement of inflammation.

Effect of salinity on Brassica rapa var. toria (BRSRT under selenium defence: A trial to assess the protective role of selenium

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Akanksha SAO

2017-12-01

Full Text Available The present study assesses the role of selenium, an antioxidant in salt-stressed plants. A hydroponic trial of sodium selenate (Na2SeO4 on the growth, oxidative stress and antioxidant protection system of Brassica rapa var. toria (BRSRT plant was studied. 40 µmol and 100 µmol of Na2SeO4 were hydroponically applied to BRSRT roots with 50 mmol and 100 mmol sodium chloride (NaCl for 12 days. Plant growth, biomass production and photosynthetic pigments at 100 mmol salt stress was inhibited while oxidative stress indicators, for example, hydrogen peroxide and lipid peroxidation were stimulated. Supplementation of 40 µmol Na2SeO4 with 50 mmol and 100 mmol NaCl improved growth, photosynthetic pigments and acted as an antioxidant by inhibiting lipid peroxidation and increasing superoxide dismutase, ascorbate peroxidase, catalase, glutathione peroxidase, glutathione reductase activities. The in-gel assays also showed enhanced activities of these enzymes. At 100 µmol concentration, selenium under salt stress, repressed growth and expression of antioxidant enzymes and stimulated oxidative stress with enhanced glutathione peroxidase activity. Under consolidated stress treatment, an addition of 40 µmol Na2SeO4 was the most effective for both NaCl concentrations. The finding reveals that the optimal selenium supplementation presents a promising potential for use in conditions of relatively high levels of NaCl stress for BRSRT seedlings.

Selenium supplementation restores the antioxidative capacity and prevents cell damage in bone marrow stromal cells in vitro

DEFF Research Database (Denmark)

Ebert, Regina; Ulmer, Matthias; Zeck, Sabine

2006-01-01

signaling, cumulative cell damage, senescence, and tumor development. Selenium-dependent (glutathione peroxidases [GPxs] and thioredoxin reductases [TrxRs]) and selenium-independent (superoxide dismutases [SODs] and catalase [CAT]) enzyme systems regulate cellular ROS steady state levels. SODs process...

Glutathione peroxidases of the potato cyst nematode Globodera Rostochiensis

NARCIS (Netherlands)

Jones, J.T.; Reavy, B.; Smant, G.; Prior, A.E.

2004-01-01

We report the cloning and characterisation of full-length DNAs complementary to RNA (cDNAs) encoding two glutathione peroxidases (GpXs) from a plant parasitic nematode, the potato cyst nematode (PCN) Globodera rostochiensis. One protein has a functional signal peptide that targets the protein for

Blood Haematology, Serum Thyroid Hormones and Glutathione Peroxidase Status in Kacang Goats Fed Inorganic Iodine and Selenium Supplemented Diets

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Z. A. Aghwan

2013-11-01

Full Text Available The effects of dietary supplementation of selenium (Se, iodine (I, and a combination of both on the blood haematology, serum free thyroxine (FT4 and free triiodothyronine (FT3 hormones and glutathione peroxidase enzyme (GSH-Px activity were examined on twenty four (7 to 8 months old, 22±1.17 kg live weight Kacang crossbred male goats. Animals were randomly assigned to four dietary treatments (6 animals in each group. Throughout 100 d of feeding trial, the animals of control group (CON received a basal diet, while the other three groups were offered basal diet supplemented with 0.6 mg/kg diet DM Se (SS, or 0.6 mg/kg diet DM I (PI, or a combination of both Se and I, each at 0.6 mg/kg diet DM (SSPI. The haematological attributes which are haemoglobin (Hb, red blood cell (RBC, packed cell volume (PCV, mean cell volume (MCV, white blood cells (WBC, band neutrophils (B Neut, segmented neutrophils (S Neut, lymphocytes (Lymph, monocytes (Mono, eosinophils (Eosin and basophils (Baso were similar among the four treatment groups, while serum levels of Se and I increased significantly (p<0.05 in the supplemented groups. The combined dietary supplementation of Se and I (SSPI significantly increased serum FT3 in the supplemented animals. Serum GSH-Px activity increased significantly in the animals of SS and SSPI groups. It is concluded that the dietary supplementation of inorganic Se and I at a level of 0.6 mg/kg DM increased serum Se and I concentration, FT3 hormone and GSH-Px activity of Kacang crossbred male goats.

Selenium, selenoproteins and the thyroid gland: interactions in health and disease.

Science.gov (United States)

Schomburg, Lutz

2011-10-18

The trace element selenium is an essential micronutrient that is required for the biosynthesis of selenocysteine-containing selenoproteins. Most of the known selenoproteins are expressed in the thyroid gland, including some with still unknown functions. Among the well-characterized selenoproteins are the iodothyronine deiodinases, glutathione peroxidases and thioredoxin reductases, enzymes involved in thyroid hormone metabolism, regulation of redox state and protection from oxidative damage. Selenium content in selenium-sensitive tissues such as the liver, kidney or muscle and expression of nonessential selenoproteins, such as the glutathione peroxidases GPx1 and GPx3, is controlled by nutritional supply. The thyroid gland is, however, largely independent from dietary selenium intake and thyroid selenoproteins are preferentially expressed. As a consequence, no explicit effects on thyroid hormone profiles are observed in healthy individuals undergoing selenium supplementation. However, low selenium status correlates with risk of goiter and multiple nodules in European women. Some clinical studies have demonstrated that selenium-deficient patients with autoimmune thyroid disease benefit from selenium supplementation, although the data are conflicting and many parameters must still be defined. The baseline selenium status of an individual could constitute the most important parameter modifying the outcome of selenium supplementation, which might primarily disrupt self-amplifying cycles of the endocrine-immune system interface rectifying the interaction of lymphocytes with thyroid autoantigens. Selenium deficiency is likely to constitute a risk factor for a feedforward derangement of the immune system-thyroid interaction, while selenium supplementation appears to dampen the self-amplifying nature of this derailed interaction.

Effects of cyanide on selenium metabolism in rats

International Nuclear Information System (INIS)

Beilstein, M.A.; Whanger, P.D.

1984-01-01

Adult male rats were given drinking water containing either 0 or 150 ppm cyanide for 2 weeks. They were then injected with 5 microCi 75 Se-selenite, and excretion of radioactivity in urine and feces was determined. No difference in excretion of 75 Se occurred during the rapid phase, but the cyanide-treated rats (T1/2 28 days) excreted significantly more 75 Se in urine than control (T1/2 38 days) rats. Cyanide had no effect on excretion of 75 Se in feces or on the distribution of 75 Se in cytosolic proteins in liver, kidney, muscle or testes. In a second experiment weanling male rats were given water with either 0 or 150 ppm cyanide and were killed for glutathione peroxidase assay and selenium analysis in blood, kidney, liver, muscle and testes after 3, 6 or 9 weeks of treatment. Glutathione peroxidase activity and selenium concentrations were significantly reduced by cyanide in all tissues except testes

Epigallocatechin-3-gallate enhances key enzymatic activities of hepatic thioredoxin and glutathione systems in selenium-optimal mice but activates hepatic Nrf2 responses in selenium-deficient mice

Directory of Open Access Journals (Sweden)

Ruixia Dong

2016-12-01

Full Text Available Selenium participates in the antioxidant defense mainly through a class of selenoproteins, including thioredoxin reductase. Epigallocatechin-3-gallate (EGCG is the most abundant and biologically active catechin in green tea. Depending upon the dose and biological systems, EGCG may function either as an antioxidant or as an inducer of antioxidant defense via its pro-oxidant action or other unidentified mechanisms. By manipulating the selenium status, the present study investigated the interactions of EGCG with antioxidant defense systems including the thioredoxin system comprising of thioredoxin and thioredoxin reductase, the glutathione system comprising of glutathione and glutathione reductase coupled with glutaredoxin, and the Nrf2 system. In selenium-optimal mice, EGCG increased hepatic activities of thioredoxin reductase, glutathione reductase and glutaredoxin. These effects of EGCG appeared to be not due to overt pro-oxidant action because melatonin, a powerful antioxidant, did not influence the increase. However, in selenium-deficient mice, with low basal levels of thioredoxin reductase 1, the same dose of EGCG did not elevate the above-mentioned enzymes; intriguingly EGCG in turn activated hepatic Nrf2 response, leading to increased heme oxygenase 1 and NAD(PH:quinone oxidoreductase 1 protein levels and thioredoxin activity. Overall, the present work reveals that EGCG is a robust inducer of the Nrf2 system only in selenium-deficient conditions. Under normal physiological conditions, in selenium-optimal mice, thioredoxin and glutathione systems serve as the first line defense systems against the stress induced by high doses of EGCG, sparing the activation of the Nrf2 system.

Radioimmunoassays for catalase and glutathion peroxidase

International Nuclear Information System (INIS)

Baret, A.; Courtiere, A.; Lorry, D.; Puget, K.; Michelson, A.M.

1982-01-01

Specific and sensitive radioimmunoassays for human, bovine and rat catalase (CAT) and glutathion Peroxidase (GPX) are described. The obtained values are expressed as enzymatic units per μg of immunoreactive protein. They appear to closely correspond to specific activities of the purified enzymes determined by colorimetric protein-assay. Indeed, the values of the specific activities of purified human CAT is 57.9 k/mg and that of purified rat GPX is 180 units/mg. This result validates the present RIAs and the association of the two techniques allows the determination of a further parameter. In conclusion, RIAs for CAT and GPX can be applied with great specificity and sensitivity to a wide variety of human, rat and bovine medias

Absorption and retention of selenium from shrimps in man

DEFF Research Database (Denmark)

Bugel, S. H.; Sandstrom, B.; Larsen, Erik Huusfeldt

2001-01-01

This study was undertaken to evaluate the bioavailability of selenium in shrimps, a possible good source of selenium, by measurements of the absorption and retention of selenium and the effects on plasma selenium concentration and glutathione peroxidase activity. Twelve healthy young subjects (9F...... of the study, after 2, 4, and 6 weeks. The selenium intake increased from 39.4 +/- 15.3 mug/d to 127 +/- 5.5 mug/d with the addition of shrimps. The apparent absorption of selenium from shrimps was 83 +/- 4%, Faecal and urinary selenium excretion was 32.5 +/- 17.0 mug/d and 21.2 +/- 9.0 mug/d, re spectively...... and the total retention of selenium was 3.1 +/- 1.1 mg. Plasma selenium concentrations were 95.2 +/- 9.7 mug/L and 101.5 +/- 9.7 mug/L before and after six weeks of shrimp intake, respectively (p...

Effects of various anesthesia maintenance on serum levels of selenium, copper, zinc, iron and antioxidant capacity

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Mehmet Akin

2015-02-01

Full Text Available BACKGROUND AND OBJECTIVES: In this study, we aimed to investigate the effects of sevoflurane, desflurane and propofol maintenances on serum levels of selenium, copper, zinc, iron, malondialdehyde, and glutathion peroxidase measurements, and antioxidant capacity. METHODS: 60 patients scheduled for unilateral lower extremity surgery which would be performed with tourniquet under general anesthesia were divided into three groups. Blood samples were collected to determine the baseline serum levels of selenium, copper, zinc, iron, malondialdehyde and glutathion peroxidase. Anesthesia was induced using 2-2.5 mg kg-1 propofol, 1 mg kg-1 lidocaine and 0.6 mg kg-1 rocuronium. In the maintenance of anesthesia, under carrier gas of 50:50% O2:N2O 4 L min-1, 1 MAC sevoflorane was administered to Group S and 1 MAC desflurane to Group D; and under carrier gas of 50:50% O2:air 4 L min-1 6 mg kg h-1 propofol and 1 µg kg h-1 fentanyl infusion were administered to Group P. At postoperative blood specimens were collected again. RESULTS: It was observed that only in Group S and P, levels of MDA decreased at postoperative 48th hour; levels of glutathion peroxidase increased in comparison to the baseline values. Selenium levels decreased in Group S and Group P, zinc levels decreased in Group P, and iron levels decreased in all three groups, and copper levels did not change in any groups in the postoperative period. CONCLUSION: According to the markers of malondialdehyde and glutathion peroxidase, it was concluded that maintenance of general anesthesia using propofol and sevoflurane activated the antioxidant system against oxidative stress and using desflurane had no effects on oxidative stress and antioxidant system.

Activation of glutathione peroxidase via Nrf1 mediates genistein's protection against oxidative endothelial cell injury

International Nuclear Information System (INIS)

Hernandez-Montes, Eva; Pollard, Susan E.; Vauzour, David; Jofre-Montseny, Laia; Rota, Cristina; Rimbach, Gerald; Weinberg, Peter D.; Spencer, Jeremy P.E.

2006-01-01

Cellular actions of isoflavones may mediate the beneficial health effects associated with high soy consumption. We have investigated protection by genistein and daidzein against oxidative stress-induced endothelial injury. Genistein but not daidzein protected endothelial cells from damage induced by oxidative stress. This protection was accompanied by decreases in intracellular glutathione levels that could be explained by the generation of glutathionyl conjugates of the oxidised genistein metabolite, 5,7,3',4'-tetrahydroxyisoflavone. Both isoflavones evoked increased protein expression of γ-glutamylcysteine synthetase-heavy subunit (γ-GCS-HS) and increased cytosolic accumulation and nuclear translocation of Nrf2. However, only genistein led to increases in the cytosolic accumulation and nuclear translocation of Nrf1 and the increased expression of and activity of glutathione peroxidase. These results suggest that genistein-induced protective effects depend primarily on the activation of glutathione peroxidase mediated by Nrf1 activation, and not on Nrf2 activation or increases in glutathione synthesis

Selenium and vitamin E inhibit radiogenic and chemically induced transformation in vitro via different mechanisms

International Nuclear Information System (INIS)

Borek, C.; Ong, A.; Mason, H.; Donahue, L.; Biaglow, J.E.

1986-01-01

Results from in vivo and in vitro studies showing that antioxidants may act as anticarcinogens support the role of active oxygen in carcinogenesis and provide impetus for exploring the functions of dietary antioxidants in cancer prevention by using in vitro models. The authors examined the single and combined effects of selenium, a component of glutathione peroxidase, and vitamin E, a known antioxidant, on cell transformation induced in C3H/10T-1/2 cells by x-rays, benzo[a]pyrene, or tryptophan pyrolysate and on the levels of cellular scavenging systems peroxide destruction. Incubation of C3H/10T-1/2 cells with 2.5 μM Na 2 SeO 3 (selenium) or with 7 μM α-tocopherol succinate (vitamin E) 24 hr prior to exposure to x-rays or the chemical carcinogens resulted in an inhibition of transformation by each of the antioxidants with an additive-inhibitory action when the two nutrients were combined. Cellular pretreatment with selenium resulted in increased levels of cellular glutathione peroxidase, catalase, and nonprotein thiols (glutathione) and in an enhanced destruction of peroxide. The results support our earlier studies showing that free radical-mediated events play a role in radiation and chemically induced transformation. They indicate that selenium and vitamin E act alone and in additive fashion as radioprotecting and chemopreventing agents. The results further suggest that selenium confers protection in part by inducing or activating cellular free-radical scavenging systems and by enhancing peroxide breakdown while vitamin E appears to confer its protection by and alternate complementary mechanism

Expression of Glutathione Peroxidase and Glutathione Reductase and Level of Free Radical Processes under Toxic Hepatitis in Rats

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Igor Y. Iskusnykh

2013-01-01

Full Text Available Correlation between intensity of free radical processes estimated by biochemiluminesce parameters, content of lipoperoxidation products, and changes of glutathione peroxidase (GP, EC 1.11.1.9 and glutathione reductase (GR, EC 1.6.4.2 activities at rats liver injury, after 12, 36, 70, 96, 110, and 125 hours & tetrachloromethane administration have been investigated. The histological examination of the liver sections of rats showed that prominent hepatocytes with marked vacuolisation and inflammatory cells which were arranged around the necrotic tissue are more at 96 h after exposure to CCl4. Moreover maximum increase in GR and GP activities, 2.1 and 2.5 times, respectively, was observed at 96 h after exposure to CCl4, what coincided with the maximum of free radical oxidation processes. Using a combination of reverse transcription and real-time polymerase chain reaction, expression of the glutathione peroxidase and glutathione reductase genes (Gpx1 and Gsr was analyzed by the determination of their respective mRNAs in the rat liver tissue under toxic hepatitis conditions. The analyses of Gpx1 and Gsr expression revealed that the transcript levels increased in 2.5- and 3.0-folds, respectively. Western blot analysis revealed that the amounts of hepatic Gpx1 and Gsr proteins increased considerably after CCl4 administration. It can be proposed that the overexpression of these enzymes could be a mechanism of enhancement of hepatocytes tolerance to oxidative stress.

[The role of selenium in endocrine system diseases].

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Balázs, Csaba; Rácz, Károly

2013-10-13

Oxygen derived free radicals, generated by a number of cellular reactions, include superoxide anion, hydrogen peroxide and hydroxyl radicals. They exert their cytotoxic effects mainly via peroxidation of the cell membrane resulting in the loss of membrane integrity. The essential trace element, selenium exerts complex effects on the endocrine systems, partly due to its antioxidant capacity. Well-characterized selenoproteins include iodothyronine deiodinases, glutathione peroxidases and thioredoxin reductases involved in thyroid hormone metabolism and protection from oxidative damage. The value of selenium supplementation in autoimmune thyroid disorders has been investigated and most studies confirmed the beneficial effect of selenium supplementation in Hashimoto's and Graves's diseases. Recently, selenium proved to be effective in mild inflammatory orbitopathy. There are a number of reports about the effect of selenium in diabetes mellitus, but the data are controversial as both insulin-like and diabetes-inducing effects of selenium have been described. Selenium was successfully used in both female and male infertility of autoimmune origin.

A novel plant glutathione S-transferase/peroxidase suppresses Bax lethality in yeast

DEFF Research Database (Denmark)

Kampranis, S C; Damianova, R; Atallah, M

2000-01-01

The mammalian inducer of apoptosis Bax is lethal when expressed in yeast and plant cells. To identify potential inhibitors of Bax in plants we transformed yeast cells expressing Bax with a tomato cDNA library and we selected for cells surviving after the induction of Bax. This genetic screen allows...... for the identification of plant genes, which inhibit either directly or indirectly the lethal phenotype of Bax. Using this method a number of cDNA clones were isolated, the more potent of which encodes a protein homologous to the class theta glutathione S-transferases. This Bax-inhibiting (BI) protein was expressed...... in Escherichia coli and found to possess glutathione S-transferase (GST) and weak glutathione peroxidase (GPX) activity. Expression of Bax in yeast decreases the intracellular levels of total glutathione, causes a substantial reduction of total cellular phospholipids, diminishes the mitochondrial membrane...

Effects of cisplatin on lipid peroxidation and the glutathione redox status in the liver of male rats: The protective role of selenium

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Trbojević Ivana S.

2010-01-01

Full Text Available The role of oxidative stress in cisplatin (CP toxicity and its prevention by pretreatment with selenium (Se was investigated. Male Wistar albino rats were injected with a single dose of cisplatin (7.5 mg CP/kg b.m., i.p. and selenium (6 mg Se/kg b.m, as Na2SeO3, i.p. alone or in combination. The results suggest that CP intoxication induces oxidative stress and alters the glutathione redox status: reduced glutathione (GSH, oxidized glutathione (GSSG and the GSH/GSSG ratio (GSH RI, resulting in increased lipid peroxidation (LPO in rat liver. The pretreatment with selenium prior to CP treatment showed a protective effect against the toxic influence of CP on peroxidation of the membrane lipids and an altering of the glutathione redox status in the liver of rats. From our results we conclude that selenium functions as a potent antioxidant and suggest that it can control CP-induced hepatotoxicity in rats.

Role of selenium toxicity and oxidative stress in aquatic birds

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Hoffman, D.J.

2002-01-01

Adverse effects of selenium (Se) in wild aquatic birds have been documented as a consequence of pollution of the aquatic environment by subsurface agricultural drainwater and other sources. These effects include mortality, impaired reproduction with teratogenesis, reduced growth, histopathological lesions and alterations in hepatic glutathione metabolism. A review is provided, relating adverse biological effects of Se in aquatic birds to altered glutathione metabolism and oxidative stress. Laboratory studies, mainly with an organic form of Se, selenomethionine, have revealed oxidative stress in different stages of the mallard (Anas platyrhynchos) life cycle. As dietary and tissue concentrations of Se increase, increases in plasma and hepatic GSH peroxidase activities occur, followed by dose-dependent increases in the ratio of hepatic oxidized to reduced glutathione (GSSG:GSH) and ultimately hepatic lipid peroxidation measured as an increase in thiobarbituric acid reactive substances (TBARS). One or more of these oxidative effects were associated with teratogenesis (4.6 ppm wet weight Se in eggs), reduced growth in ducklings (15 ppm Se in liver), diminished immune function (5 ppm Se in liver) and histopathological lesions (29 ppm Se in liver) in adults. Manifestations of Serelated effects on glutathione metabolism were also apparent in field studies in seven species of aquatic birds. Reduced growth and possibly immune function but increased liver:body weight and hepatic GSSG:GSH ratios were apparent in American avocet (Recurvirostra americana) hatchlings from eggs containing 9 ppm Se. In blacknecked stilts (Himantopus mexicanus), which contained somewhat lower Se concentrations, a decrease in hepatic GSH was apparent with few other effects. In adult American coots (Fulica americana), signs of Se toxicosis included emaciation, abnormal feather loss and histopathological lesions. Mean liver concentrations of 28 ppm Se (ww) in the coots were associated with elevated

The impact of GPX1 on the association of groundwater selenium and depression: a project FRONTIER study

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Johnson Leigh A

2013-01-01

Full Text Available Abstract Background Prior animal model and human-based studies have linked selenium concentrations to decreased risk for depression; however, this work has not focused on household groundwater levels or specific depressive symptoms. The current study evaluated the link between groundwater selenium levels and depression. We also sought to determine if a functional polymorphism in the glutathione peroxidase 1 (GPX1 gene impacted this link. Methods We used a cross-sectional design to analyze data from 585 participants (183 men and 402 women from Project FRONTIER, a study of rural health in West Texas. Residential selenium concentrations were estimated using Geospatial Information System (GIS analyses. Linear regression models were created using Geriatric Depression Scale (GDS-30 total and subfactor scores as outcome variables and selenium concentrations as predictor variables. Analyses were re-run after stratification of the sample on GPX1 Pro198Leu genotype (rs1050454. Results Selenium levels were significantly and negatively related to all GDS and subfactor scores accounting for up to 17% of the variance beyond covariates. Selenium was most strongly protective against depression among homozygous carriers of the C allele at the Pro198Leu polymorphism of the GPX1 gene. Analyses also point towards a gene-environmental interaction between selenium exposure and GPX1 polymorphism. Conclusion Our results support the link between groundwater selenium levels and decreased depression symptoms. These findings also highlight the need to consider the genetics of the glutathione peroxidase system when examining this relationship, as variation in the GPX1 gene is related to depression risk and significantly influences the protective impact of selenium, which is indicative of a gene-environment interaction.

Effect of chronic selenium exposure on the freshwater bivalve Corbicula fluminea

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Fournier, E.; Adam, C.; Massabuau, J.C.; Garnier-Laplace, J. [CEA Cadarache (DEI/SECRE/LRE), Laboratory of Radioecology and Ecotoxicology, Institute for Radioprotection and Nuclear Safety, 13 - Saint-Paul-lez-Durance (France)

2004-07-01

Selenium is essential for most of living organisms. In oxic to moderately oxic fresh-waters, Se exists predominantly in the (+VI) and (+IV) oxidation states as selenate (SeO{sub 4}{sup 2-}) and selenite (SeO{sub 3}{sup 2-}) respectively, whereas in the biota it is incorporated as Se(-II) into seleno-proteins or amino-acids, or as elemental selenium Se(0). At low concentrations, it acts against oxidative damages mainly as the glutathione peroxidase seleno-dependant, but it may be toxic at higher levels (for example, by replacing sulphur in important biomolecules). In filter feeders, such as the freshwater bivalve Corbicula fluminea, selected as biological model, the ventilation activity is a primary limiting step that controls the water influx and therefore the delivery of contaminants. Consequently, a series of short-term experiments were performed to study the effects of different dissolved Se concentrations and forms (selenite; selenate; selenomethionine) on the ventilation activity of Corbicula fluminea and Se tissular distribution. The modification of the ventilation activity of the Se-exposed groups, in comparison to this of reference groups (not exposed to Se) varied greatly according to the form and the concentrations of the Se used. Se concentrations in tissues indicated that selenite was the less bioavailable form whereas selenomethionine displayed the opposite trend. On the basis of this set of experiments, a limited number of conditions have been selected to provide highly contrasting ventilation flow rates and selenium bioaccumulation levels, in order to study the effects of long term exposures, i) at the molecular level, by measuring bio-markers of oxidative stress (forms of glutathione, glutathione peroxidase, glutathione reductase, superoxide dismutase, catalase, and bio-marker of genotoxicity (comet assay), ii) at the (sub)cellular level by analysing Se micro-localisation in target organs and iii) at the individual level by monitoring the variation

Investigation of glutathione peroxidase activity in chicken meat under different experimental conditions

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Alexandre José Cichoski

2012-12-01

Full Text Available Due to the fact that previous studies on the enzymatic activity of Glutathione peroxidase (GSH-Px diverge widely in their methodology and results, this study aimed to investigate the influence of different analytical conditions on GSH-Px activity in chicken thighs from broilers that were fed different diets with different sources and concentrations of selenium. GSH-Px activity was evaluated six hours after slaughter and 120 days after frozen storage at -18 ºC. The different analytical conditions included time of pre-incubation (0, 10 and 30 minutes, reaction medium, types of substrate (H2O2 (0.72 mM, 7.2 mM, and 72 mM and Terc-butil hydroperoxide 15 mM, and different buffer concentrations (buffer 1, potassium phosphate 50 mM pH 7.0 + EDTA 1 mM + mercaptoethanol 1 mM, and buffer 2, tris-HCl 50 mM pH 7.6 + EDTA 1 mM + mercapthanol 5 mM. The results show that the highest GSH-Px activity was observed when enzyme and substrate were in contact at 22 ºC without any pre-incubation, and that, when used at concentrations above 0.72 mM, hydrogen peroxide saturated the GSH-Px enzyme and inhibited its activity. The enzyme presented higher affinity to hydrogen peroxide when compared to terc-butil peroxide, and the addition of a buffer containing mercaptoethanol did not increase GSH-Px enzymatic activity. The activity of GSH-Px was not influenced by the source and concentration of selenium in the diet either. The obtained results allowed the determination of the best temperature of contact between the enzyme and substrate (22 ºC, the optimum concentration, and the type of substrate and buffer to be used. This information is extremely useful for future studies on GSH-Px activity in meat due to the divergence and little information found in the literature.

Effects of mercury and selenium on glutathione metabolism and oxidative stress in mallard ducks

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Hoffman, D.J.; Heinz, G.H.

1998-01-01

Earlier studies reported on the toxicity and related oxidative stress of different forms of Se, including seleno-D,L-methionine, in mallards (Anas platyrhynchos). This study compares the effects of Se (seleno-D,L-methionine) and Hg (methylmercury chloride) separately and in combination. Mallard drakes received one of the following diets: untreated feed (controls), or feed containing 10 ppm Se, 10 ppm Hg, or 10 ppm Se in combination with 10 ppm Hg. After 10 weeks, blood, liver, and brain samples were collected for biochemical assays. The following clinical and biochemical alterations occurred in response to mercury exposure: hematocrit and hemoglobin concentrations decreased; activities of the enzymes glutathione (GSH) peroxidase (plasma and liver), glutathione-S-transferase (liver), and glucose-6-phosphate dehydrogenase (G-6-PDH) (liver and brain) decreased; hepatic oxidized glutathione (GSSG) concentration increased relative to reduced glutathione (GSH); and lipid peroxidation in the brain was evident as detected by increased thiobarbituric reactive substances (TBARS). Effects of Se alone included increased hepatic GSSG reductase activity and brain TBARS concentration. Se in combination with Hg partially or totally alleviated effects of Hg on GSH peroxidase, G-6-PDH, and GSSG. These findings are compared in relation to field observations for diving ducks and other aquatic birds. It is concluded that since both Hg and excess Se can affect thiol status, measurement of associated enzymes in conjunction with thiol status may be a useful bioindicator to discriminate between Hg and Se effects. The ability of Se to restore the activities of G-6-PDH, GSH peroxidase, and glutathione status involved in antioxidative defense mechanisms may be crucial to biological protection from the toxic effects of methyl mercury.

Selenium and the thyroid: A close-knit connection

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Ashok K Bhuyan

2012-01-01

Full Text Available Introduction: In areas with severe selenium deficiency higher incidence of thyroiditis has been reported due to a decreased activity of selenium-dependent glutathione peroxidase enzyme within thyroid cells. Aims and Objective: To study the effect of selenium supplementation in patients with autoimmune thyroid disease. Materials and Methods: This is a blinded placebo-controlled prospective study done in 60 patients with autoimmune thyroid disease (as defined by an anti-thyroid peroxidase antibody (TPOAb level more than 150 IU/ml irrespective of the baseline thyroid status. Patients with overt hyperthyroidism who are on antithyroid drugs, patients on any other medication, which may alter the immunity status of the patients, and pregnant patients were excluded from the study. Patients were randomized into two age and TPOAb-matched groups; 30 patients received 200 μg of sodium selenite/day, orally, for 3 months, and 30 patients received placebo. All hypothyroid patients were given l-thyroxine replacement. Results: Of 30 patients in the selenium treated group, 6 patients were overtly hypothyroid, 15 were subclinical hypothyroid, 6 were euthyroid, and 3 were subclinical hyperthyroid. The mean TPOAb concentration decreased significantly by 49.5% (P < 0.013 in the selenium treated group versus 10.1% (P < 0.95 in the placebo-treated group. Conclusion: Selenium substitution has a significant impact on inflammatory activity in thyroid-specific autoimmune disease. It would be of interest to determine whether early treatment with selenium in patients with newly developed autoimmune thyroiditis may delay or even prevent the natural course of these diseases.

The Small Glutathione Peroxidase Mimic 5P May Represent a New Strategy for the Treatment of Liver Cancer.

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Yin, Juxin; Wang, Bingmei; Zhu, Xuejun; Qu, Xiaonan; Huang, Yi; Lv, Shaowu; Mu, Ying; Luo, Guimin

2017-09-08

Glutathione peroxidase (GPx) is an antioxidant protein containing selenium. Owing to the limitations of native GPx, considerable efforts have been made to develop GPx mimics. Here, a short 5-mer peptides (5P) was synthesized and characterized using matrix-assisted laser desorption ionization time-of-flight mass spectrometry. Enzyme coupled assays were used to evaluate GPx activity. The cell viability and apoptosis of H22 cells were tested, and mice bearing H22 cell-derived tumors were used to determine the effects of 5P on tumor inhibition. In comparison with other enzyme models, 5P provided a suitable substrate with proper catalytic site positions, resulting in enhanced catalytic activity. In our mouse model, 5P showed excellent inhibition of tumor growth and improved immunity. In summary, our findings demonstrated the design and synthesis of the small 5P molecule, which inhibited tumor growth and improved immunity. Notably, 5P could inhibit tumor growth without affecting normal growth. Based on these advantages, the novel mimic may have several clinical applications.

Relationship between oxidizable fatty acid content and level of antioxidant glutathione peroxidases in marine fish

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Grim, Jeffrey M.; Hyndman, Kelly A.; Kriska, Tamas; Girotti, Albert W.; Crockett, Elizabeth L.

2011-01-01

SUMMARY Biological membranes can be protected from lipid peroxidation by antioxidant enzymes including catalase (CAT) and selenium-dependent glutathione peroxidases 1 and 4 (GPx1 and GPx4). Unlike GPx1, GPx4 can directly detoxify lipid hydroperoxides in membranes without prior action of phospholipase A2. We hypothesized that (1) GPx4 is enhanced in species that contain elevated levels of highly oxidizable polyunsaturated fatty acids (PUFA) and (2) activities of antioxidant enzymes are prioritized to meet species-specific oxidative stresses. In this study we examined (i) activities of the oxidative enzyme citrate synthase (CS) and antioxidant (CAT, GPx1 and GPx4) enzymes, (ii) GPx4 protein expression, and (iii) phospholipid composition in livers of five species of marine fish (Myxine glutinosa, Petromyzon marinus, Squalus acanthias, Fundulus heteroclitus and Myoxocephalus octodecemspinosus) that contain a range of PUFA. GPx4 activity was, on average, 5.8 times higher in F. heteroclitus and S. acanthias than in the other three marine fish species sampled. Similarly, activities of CAT and GPx1 were highest in S. acanthias and F. heteroclitus, respectively. GPx4 activity for all species correlates with membrane unsaturation, as well as oxidative activity as indicated by CS. These data support our hypothesis that GPx4 level in marine fish is a function, at least in part, of high PUFA content in these animals. GPx1 activity was also correlated with membrane unsaturation, indicating that marine species partition resources among glutathione-dependent defenses for protection from the initial oxidative insult (e.g. H2O2) and to repair damaged lipids within biological membranes. PMID:22031739

Effects of topical vitamin E on corneal superoxide dismutase, glutathione peroxidase activities and polymorphonuclear leucocyte infiltration after photorefractive keratectomy.

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Bilgihan, Ayse; Bilgihan, Kamil; Yis, Ozgür; Sezer, Cem; Akyol, Gülen; Hasanreisoglu, Berati

2003-04-01

Photorefractive keratectomy (PRK) induces free radical formation and polymorphonuclear (PMN) cell infiltration in the cornea. Vitamin E is a free radical scavenger and protects the cells from reactive oxygen species. We investigated the effects of topical vitamin E on corneal PMN cell infiltration and corneal antioxidant enzyme activities after PRK. We studied four groups, each consisting of seven eyes. Group 1 were control eyes. In group 2 the corneal epithelium was removed by a blunt spatula (epithelial scrape). In group 3, corneal photoablation (59 micro m, 5 dioptres) was performed after epithelial removal (traditional PRK). In group 4 we tested the effects of topical Vitamin E after traditional PRK. Corneal tissues were removed and studied with enzymatic analysis (measurement of corneal superoxide dismutase and glutathione peroxidase activities) and histologically. Stromal PMN leucocyte counts were significantly higher after mechanical epithelial removal and traditional PRK (p < 0.05). Corneal superoxide dismutase and glutathione peroxidase activities decreased significantly after mechanical epithelial removal and traditional PRK (p < 0.05). In group 4, treated with vitamin E, corneal superoxide dismutase activity did not differ significantly from that in the medically non-treated groups, nor did corneal PMN cell infiltration after traditional PRK. The reduction of corneal glutathione peroxidase activity after PRK was reduced significantly after topical vitamin E treatment. Topical vitamin E treatment may be useful for reducing the harmful effects of reactive oxygen radical after epithelial scraping and PRK in that it increases corneal glutathione peroxidase activity.

Characterization of glutathione peroxidase diversity in the symbiotic sea anemone Anemonia viridis

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Pey , Alexis; Zamoum , Thamilla; Christen , Richard; Merle , Pierre-Laurent; Furla , Paola

2016-01-01

International audience; Cnidarians living in symbiosis with photosynthetic dinoflagellates (commonly named zooxanthellae) are exposed to high concentrations of reactive oxygen species (ROS) upon illumination. To quench ROS production, both the cnidarian host and zooxanthellae express a full suite of antioxidant enzymes. Studying antioxidative balance is therefore crucial to understanding how symbiotic cnidarians cope with ROS production. We characterized glutathione peroxidases (GPx) in the s...

Antioxidant effects of selenium on lung injury in paraquat intoxicated rats

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Kim, K.S.; Suh, G.J.; Kwon, W.Y.; Kwak, Y.H.; Lee, Kenneth; Lee, H.J.; Jeong, K.Y.; Lee, M.W.

2012-01-01

CONTEXT: Paraquat (PQ) causes lethal intoxication by inducing oxidant injury to the lung. Selenium is a cofactor for glutathione peroxidase (GPx), which is one of the major endogenous antioxidant enzymes. OBJECTIVE: To determine whether selenium post-treatment activates GPx, decreases lung injury, and improves survival in PQ intoxicated rats. MATERIALS AND METHODS: Male Spraque-Dawley rats were categorized into three groups: sham (n = 6), PQ (n = 12), and PQ + Se (n = 12). In the PQ and PQ + Se groups, 50 mg/kg of PQ was administered intraperitoneally. After 10 minutes, 60 μg/kg of Se (PQ + Se) or saline (PQ) was administered via the tail vein. Six rats per group were euthanized 6 hours or 24 hours later. Lung tissues were harvested for the measurement of GPx activity, reduced glutathione (GSH), glutathione disulfide (GSSG) and malondialdehyde (MDA) and for histological analysis. Using separated set of rats, survival of PQ (n = 10) and PQ + Se (n = 10) were observed for 72 hours. RESULTS: GPx activity in the PQ group at the 6-hour and 24-hour time points was lower than in the sham group (p CONCLUSION: Single dose of selenium post-treatment activates GPx and attenuates lipid peroxidation and lung injury early after paraquat intoxication, but does not improve 72 hours of survival.

Reduced Utilization of Selenium by Naked Mole Rats Due to a Specific Defect in GPx1 Expression*

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Kasaikina, Marina V.; Lobanov, Alexei V.; Malinouski, Mikalai Y.; Lee, Byung Cheon; Seravalli, Javier; Fomenko, Dmitri E.; Turanov, Anton A.; Finney, Lydia; Vogt, Stefan; Park, Thomas J.; Miller, Richard A.; Hatfield, Dolph L.; Gladyshev, Vadim N.

2011-01-01

Naked mole rat (MR) Heterocephalus glaber is a rodent model of delayed aging because of its unusually long life span (>28 years). It is also not known to develop cancer. In the current work, tissue imaging by x-ray fluorescence microscopy and direct analyses of trace elements revealed low levels of selenium in the MR liver and kidney, whereas MR and mouse brains had similar selenium levels. This effect was not explained by uniform selenium deficiency because methionine sulfoxide reductase activities were similar in mice and MR. However, glutathione peroxidase activity was an order of magnitude lower in MR liver and kidney than in mouse tissues. In addition, metabolic labeling of MR cells with 75Se revealed a loss of the abundant glutathione peroxidase 1 (GPx1) band, whereas other selenoproteins were preserved. To characterize the MR selenoproteome, we sequenced its liver transcriptome. Gene reconstruction revealed standard selenoprotein sequences except for GPx1, which had an early stop codon, and SelP, which had low selenocysteine content. When expressed in HEK 293 cells, MR GPx1 was present in low levels, and its expression could be rescued neither by removing the early stop codon nor by replacing its SECIS element. In addition, GPx1 mRNA was present in lower levels in MR liver than in mouse liver. To determine if GPx1 deficiency could account for the reduced selenium content, we analyzed GPx1 knock-out mice and found reduced selenium levels in their livers and kidneys. Thus, MR is characterized by the reduced utilization of selenium due to a specific defect in GPx1 expression. PMID:21372135

Modular evolution of glutathione peroxidase genes in association with different biochemical properties of their encoded proteins in invertebrate animals

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Zo Young-Gun

2009-04-01

Full Text Available Abstract Background Phospholipid hydroperoxide glutathione peroxidases (PHGPx, the most abundant isoforms of GPx families, interfere directly with hydroperoxidation of lipids. Biochemical properties of these proteins vary along with their donor organisms, which has complicated the phylogenetic classification of diverse PHGPx-like proteins. Despite efforts for comprehensive analyses, the evolutionary aspects of GPx genes in invertebrates remain largely unknown. Results We isolated GPx homologs via in silico screening of genomic and/or expressed sequence tag databases of eukaryotic organisms including protostomian species. Genes showing strong similarity to the mammalian PHGPx genes were commonly found in all genomes examined. GPx3- and GPx7-like genes were additionally detected from nematodes and platyhelminths, respectively. The overall distribution of the PHGPx-like proteins with different biochemical properties was biased across taxa; selenium- and glutathione (GSH-dependent proteins were exclusively detected in platyhelminth and deuterostomian species, whereas selenium-independent and thioredoxin (Trx-dependent enzymes were isolated in the other taxa. In comparison of genomic organization, the GSH-dependent PHGPx genes showed a conserved architectural pattern, while their Trx-dependent counterparts displayed complex exon-intron structures. A codon for the resolving Cys engaged in reductant binding was found to be substituted in a series of genes. Selection pressure to maintain the selenocysteine codon in GSH-dependent genes also appeared to be relaxed during their evolution. With the dichotomized fashion in genomic organizations, a highly polytomic topology of their phylogenetic trees implied that the GPx genes have multiple evolutionary intermediate forms. Conclusion Comparative analysis of invertebrate GPx genes provides informative evidence to support the modular pathways of GPx evolution, which have been accompanied with sporadic

THE EFFECT OF DIFFERENT FORMS OF SELENIUM IN DIET ON LIVER FUNCTION AND BODY WEIGHT OF BROILER CHICKENS

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Zdenko Stanko Kanački

2014-12-01

Full Text Available The main biological role of selenium is performed via enzyme glutathione peroxidase, and includes the participation in the defense mechanism of the cell membrane from the peroxide damage. The aim of this study was to determine the effect of added selenium in foods in varying amounts and from various sources (organic and inorganic selenium. The experiment was conducted on the broilers, and the following parameters were monitored: body weight, total serum protein and the activity of the liver enzymes AST and ALT. The study demonstrated that organically-bound selenium had the most pronounced protective property, while both forms of selenium did not significantly affect the growth and concentration of the total serum protein. Therefore, this research suggests economic benefits of organic selenium in the diet of broiler chickens. Key words: selenium, body weight, liver function, broiler chickens

Selenistasis: Epistatic Effects of Selenium on Cardiovascular Phenotype

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Joseph Loscalzo

2013-01-01

Full Text Available Although selenium metabolism is intricately linked to cardiovascular biology and function, and deficiency of selenium is associated with cardiac pathology, utilization of selenium in the prevention and treatment of cardiovascular disease remains an elusive goal. From a reductionist standpoint, the major function of selenium in vivo is antioxidant defense via its incorporation as selenocysteine into enzyme families such as glutathione peroxidases and thioredoxin reductases. In addition, selenium compounds are heterogeneous and have complex metabolic fates resulting in effects that are not entirely dependent on selenoprotein expression. This complex biology of selenium in vivo may underlie the fact that beneficial effects of selenium supplementation demonstrated in preclinical studies using models of oxidant stress-induced cardiovascular dysfunction, such as ischemia-reperfusion injury and myocardial infarction, have not been consistently observed in clinical trials. In fact, recent studies have yielded data that suggest that unselective supplementation of selenium may, indeed, be harmful. Interesting biologic actions of selenium are its simultaneous effects on redox balance and methylation status, a combination that may influence gene expression. These combined actions may explain some of the biphasic effects seen with low and high doses of selenium, the potentially harmful effects seen in normal individuals, and the beneficial effects noted in preclinical studies of disease. Given the complexity of selenium biology, systems biology approaches may be necessary to reach the goal of optimization of selenium status to promote health and prevent disease.

Roles of catalase and glutathione peroxidase in the tolerance of a pulmonate gastropod to anoxia and reoxygenation.

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Welker, Alexis F; Moreira, Daniel C; Hermes-Lima, Marcelo

2016-07-01

Humans and most mammals suffer severe damage when exposed to ischemia and reperfusion episodes due to an overproduction of reactive oxygen species (ROS). In contrast, several hypoxia/anoxia-tolerant animals survive very similar situations. We evaluated herein the redox metabolism in the anoxia-tolerant land snail Helix aspersa after catalase inhibition by 3-amino-1,2,4-triazole (ATZ) injection during a cycle of wide and abrupt change in oxygen availability. The exposure to anoxia for 5 h caused a change of only one of several parameters related to free radical metabolism: a rise in selenium-dependent glutathione peroxidase (Se-GPX) activity in muscle of both saline- and ATZ-injected animals (by 1.9- and 1.8-fold, respectively). Catalase suppression had no effect in animals under normoxia or anoxia. However, during reoxygenation catalase suppression kept high levels of muscle Se-GPX activity (twofold higher than in saline-injected snails up to 30 min reoxygenation) and induced the increase in hepatopancreas SOD activity (by 22 %), indicating higher levels of ROS in both organs than in saline-injected animals. Additionally, catalase-suppressed snails showed 12 % higher levels of carbonyl protein-a sign of mild oxidative stress-in muscle during reoxygenation than those animals with intact catalase. No changes were observed in glutathione parameters (GSH, GSSG and GSSG:GSH ratio), TBARS, and GST activity in any of the experimental groups, in both organs. These results indicate that catalase inhibition inflicts changes in the free radical metabolism during reoxygenation, prompting a stress-response that is a reorganization in other enzymatic antioxidant defenses to minimize alterations in the redox homeostasis in land snails.

Computational Modeling of the Catalytic Cycle of Glutathione Peroxidase Nanomimic.

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Kheirabadi, Ramesh; Izadyar, Mohammad

2016-12-29

To elucidate the role of a derivative of ebselen as a mimic of the antioxidant selenoenzyme glutathione peroxidase, density functional theory and solvent-assisted proton exchange (SAPE) were applied to model the reaction mechanism in a catalytic cycle. This mimic plays the role of glutathione peroxidase through a four-step catalytic cycle. The first step is described as the oxidation of 1 in the presence of hydrogen peroxide, while selenoxide is reduced by methanthiol at the second step. In the third step of the reaction, the reduction of selenenylsulfide occurs by methanthiol, and the selenenic acid is dehydrated at the final step. Based on the kinetic parameters, step 4 is the rate-determining step (RDS) of the reaction. The bond strength of the atoms involved in the RDS is discussed with the quantum theory of atoms in molecules (QTAIM). Low value of electron density, ρ(r), and positive Laplacian values are the evidence for the covalent nature of the hydrogen bonds rupture (O 30 -H 31 , O 33 -H 34 ). A change in the sign of the Laplacian, L(r), from the positive value in the reactant to a negative character at the transition state indicates the depletion of the charge density, confirming the N 5 -H 10 and O 11 -Se 1 bond breaking. The analysis of electron location function (ELF) and localized orbital locator (LOL) of the Se 1 -N 5 and Se 1 -O 11 bonds have been done by multi-WFN program. High values of ELF and LOL at the transition state regions between the Se, N, and O atoms display the bond formation. Finally, the main donor-acceptor interaction energies were analyzed using the natural bond orbital analysis for investigation of their stabilization effects on the critical bonds at the RDS.

Effects of Fermented Mushroom of Cordyceps sinensis, Rich in Selenium, on Uterine Cervix Cancer

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Jing Ji

2014-01-01

Full Text Available The purpose of this study was to investigate the effect of fermented mushroom of Cordyceps sinensis (CS, rich in selenium (Se-CS, on uterine cervical cancer in mice. The methylcholanthrene- (MCA- induced tumor model was used in this paper. After the mice were administered Se-CS, the animals showed 40% tumor incidence (P<0.05. Se-CS also enhanced the immune functions. Se-CS treatment showed significant (P<0.05–0.01 restoration in the level of glutathione content, lipid peroxidation, glutathione peroxidase activity, glutathione reductase activity, catalase activity, Na+/K+-ATPase activity, and glutathione S transferase activity. This finding suggested that the concomitant use of Se and CS could be a potential therapeutic approach to improve the efficacy of therapy for uterine cervical cancer.

Differential regulation of glutathione peroxidase by selenomethionine and hyperoxia in endothelial cells.

Science.gov (United States)

Jornot, L; Junod, A F

1995-01-01

We have studied the effect of selenomethionine (SeMet) and hyperoxia on the expression of glutathione peroxidase (GP) in human umbilical vein endothelial cells. Incubation of HUVEC with 1 x 10(-6) M SeMet for 24 h and 48 h caused a 65% and 86% increase in GP activity respectively. The same treatment did not result in significant changes in GP gene transcription and mRNA levels. Pactamycin, a specific inhibitor of the initiation step of translation, prevented the rise in GP activity induced by SeMet and caused an increase in GP mRNA in both cells grown in normal and SeMet-supplemented medium. Interestingly, SeMet supplementation stimulated the recruitment of GP mRNA from an untranslatable pool on to polyribosomes, so that the concentration of GP mRNA in polyribosomal translatable pools was 50% higher in cells grown in SeMet-supplemented medium than in cells grown in normal medium. On the other hand, cells exposed to 95% O2 for 3 days in normal medium showed a 60%, 394% and 81% increase in GP gene transcription rate, mRNA levels and activity respectively. Hyperoxia also stabilized GP mRNA. Hyperoxic cells grown in SeMet-supplemented medium did not show any change in GP gene transcription and mRNA levels, but expressed an 81% and 100% increase in GP activity and amount of GP mRNA associated with polyribosomes respectively, when compared with hyperoxic cells maintained in normal medium. Thus, GP appeared to be regulated post-transcriptionally, most probably co-translationally, in response to selenium availability, and transcriptionally and post-transcriptionally in response to oxygen. Images Figure 1 Figure 2 Figure 4 Figure 7 Figure 8 PMID:7887914

Plasma interleukin-6 levels, glutathione peroxidase and isoprostane in obese women before and after weight loss. Association with cardiovascular risk factors.

Science.gov (United States)

Bougoulia, Maria; Triantos, Athanassios; Koliakos, George

2006-01-01

To evaluate the levels of Interleukin-6 (IL-6), glutathione peroxidase and isoprostane in obese women and their association with markers of cardiovascular risk factors before and after weight loss. 36 healthy obese women of reproductive age (group A: age (mean+/-SD) 35.4+/-9.2 years, Body Mass Index (BMI) 38.5+/-7 kg/m2) and 30 healthy, normal weight women (group B: age mean+/-SD 34.9+/-7.4 y., BMI 24+/-1.1 kg/m2) were included in the study. Glucose tolerance was normal in all participating women. Il-6, glutathione peroxidase and isoprostane, C-Reactive Protein (CRP), insulin, fasting plasma glucose, HOMA-IR as well as the lipid profile were evaluated. Body weight, BMI, Waist to Hip ratio (W/H) ratio, Waist Circumference (WC), %free fat mass and the %fat mass were also measured. A hypo-caloric diet was prescribed for the obese women and all participants were re-examined after six months. In obese women after weight loss, anthropometric obesity markers (BMI, W/H ratio), %fat, lipid profile, insulin levels and inflammation indices such as IL-6 and CRP, the oxidative stress index isoprostane, as well as glutathione peroxidase were significantly ameliorated. The levels of serum glutathione peroxidase activity were negatively correlated with IL-6 levels and were significantly increased after weight reduction. In obese women there was an association between IL-6 levels and the values of %fat, %free fat mass, insulin and HOMA-IR before and after weight loss. Weight loss is related to reduction of oxidative stress and inflammation; this beneficial effect could possibly be translated into reduction of cardiovascular risk in obese individuals.

Tumor suppressor function of the plasma glutathione peroxidase Gpx3 in colitis-associated carcinoma

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Barrett, Caitlyn W.; Ning, Wei; Chen, Xi; Smith, J. Joshua; Washington, Mary K; Hill, Kristina E.; Coburn, Lori A.; Peek, Richard M.; Chaturvedi, Rupesh; Wilson, Keith T.; Burk, Raymond F.; Williams, Christopher S.

2012-01-01

The glutathione peroxidases, a family of selenocysteine-containing redox enzymes, play pivotal roles in balancing the signaling, immunomodulatory and deleterious effects of reactive oxygen species (ROS). The glutathione peroxidase GPX3 is the only extracellular member of this family, suggesting it may defend cells against ROS in the extracellular environment. Notably, GPX3 hypermethylation and underexpression occurs commonly in prostate, gastric, cervical, thyroid and colon cancers. We took a reverse genetics approach to investigate whether GPX3 would augment inflammatory colonic tumorigenesis, a process characterized by oxidative stress and inflammation, comparing Gpx3−/− mice established two-stage model of inflammatory colon carcinogenesis. Gpx3-deficient mice exhibited an increased tumor number, though not size, along with a higher degree of dysplasia. Additionally, they exhibited increased inflammation with redistribution towards pro-tumorigenic M2 macrophage subsets, increased proliferation, hyperactive WNT signaling, and increased DNA damage. To determine the impact of acute gene loss in an established colon cancer line, we silenced GPX3 in human Caco2 cells, resulting in increased ROS production, DNA damage and apoptosis in response to oxidative stress, combined with decreased contact-independent growth. Taken together, our results suggested an immunomodulatory role for GPX3 that limits the development of colitis-associated carcinoma. PMID:23221387

Peroxidases in nanostructures

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Ana Maria eCarmona-Ribeiro

2015-09-01

Full Text Available Peroxidases are enzymes catalyzing redox reactions that cleave peroxides. Their active redox centers have heme, cysteine thiols, selenium, manganese and other chemical moieties. Peroxidases and their mimetic systems have several technological and biomedical applications such as environment protection, energy production, bioremediation, sensors and immunoassays design and drug delivery devices. The combination of peroxidases or systems with peroxidase-like activity with nanostructures such as nanoparticles, nanotubes, thin films, liposomes, micelles, nanoflowers, nanorods and others is often an efficient strategy to improve catalytic activity, targeting and reusability.

The necessity of selenium substitution in total parenteral nutrition and artificial alimentation.

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Gramm, H J; Kopf, A; Brätter, P

1995-03-01

For the trace element selenium, in contrast to zinc, iron, copper, chromium, manganese and iodine, there is still no clear official recommendation with regard to routine substitution in artificial nutrition. An overview of the manifestations of selenium deficiency in humans during the period 1979-1995 shows that nutritive deficiencies are exclusively TPN-induced or the result of severe malnutrition. The pathology of TPN-induced selenium deficiency and the analytic assessment of selenium status are described. Patients undergoing long-term parenteral nutrition or suffering from an increased loss of intestinal secretions have to be characterized as being especially at risk for clinical selenium deficiency. The relationship of the serum selenium kinetics in pediatric and adult patients to the depletion of body compartments during the course of short-term and prolonged TPN is discussed. Because of the importance of the selenoproteins, the regularly occurring depletion during selenium-free TPN and the borderline supply of selenium in Germany the routine substitution of selenium in TPN is strongly recommended. The pharmaceutical industry should be encouraged to develop a trace element solution that includes selenium, so that the nutritive requirement of patients on TPN can be satisfied. Adequate intravenous dosage recommendations are based on maintenance of glutathione peroxidase homeostasis. The routine supplementation dosage may not meet the selenium requirements of intensive care patients under conditions of increased metabolic demands on their anti-oxidative system.

The effects of the sulfonylurea glyburide on glutathione peroxidase, superoxide dismutase and catalase activities in the heart tissue of streptozotocin-induced diabetic rat.

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Bukan, N; Sancak, B; Bilgihan, A; Kosova, F; Buğdayci, G; Altan, N

2004-09-01

Oxygen free radicals have been suggested to be a contributory factor in diabetes complications. The aim of this study was to examine the effects of glyburide on the antioxidant enzyme activities in the heart tissue of diabetic rats. We investigated the activities of antioxidant enzymes (superoxide dismutase, catalase and glutathione peroxidase) in the hearts of both control and streptozotocin-induced diabetic rats. In the heart of diabetic rats, the activity of total superoxide dismutase decreased significantly (p < 0.005), whereas the activity of catalase and glutathione peroxidase increased to a large extent (p < 0.0001 and p = 0.05, respectively) at the end of the fourth week compared with the control group. Glyburide treatment of diabetic rats for 4 weeks corrected the changes observed in diabetic heart. In addition, blood glucose levels of untreated diabetic rats decreased following the glyburide treatment. These results demonstrate that the sulfonylurea glyburide is capable of exerting direct insulin-like effect on heart superoxide dismutase, catalase and glutathione peroxidase activities of diabetic rats in vivo.

A redox-dependent dimerization switch regulates activity and tolerance for reactive oxygen species of barley seed glutathione peroxidase

DEFF Research Database (Denmark)

Navrot, Nicolas; Skjoldager, Nicklas; Bunkenborg, Jakob

2015-01-01

Monomeric and dimeric forms of recombinant barley (Hordeum vulgare subsp. vulgare) glutathione peroxidase 2 (HvGpx2) are demonstrated to display distinctly different functional properties in vitro. Monomeric HvGpx2 thus has five fold higher catalytic efficiency than the dimer towards tert-butyl h...

[Is plasma selenium correlated to transthyretin levels in critically ill patients?

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Freitas, Renata G B O N; Nogueira, Roberto Jose Negrão; Cozzolino, Silvia Maria Franciscato; Vasques, Ana Carolina Junqueira; Ferreira, Matthew Thomas; Hessel, Gabriel

2017-06-05

Selenium is an essential trace element, but critically ill patients using total parenteral nutrition (PN) do not receive selenium because this mineral is not commonly offered. Threfore, the eval uation of plasma selenium levels is very important for treating or preventing this deficiency. Recent studies have shown that transthyretin may reflect the selenium intake and could be considered a biomarker. However, this issue is still little explored in the literature. This study aims to investigate the correlation of transthyretin with the plasma selenium of critically ill patients receiving PN. This was a prospective cohort study with 44 patients using PN without selenium. Blood samples were carried out in 3 stages: initial, 7th and 14th day of PN. In order to evaluate the clinical condition and the inflammatory process, albumin, C-reactive protein (CRP), transthyretin, creatinine and HDL cholesterol levels were observed. To assess the selenium status, plasma selenium and glutathione peroxidase (GPx) in whole blood were measured. Descriptive analyses were performed and the ANOVA, Mann-Whitney and Spearman's coefficient tests were conducted; we assumed a significance level of 5%. A positive correlation of selenium with the GPx levels (r = 0.46; p = 0.03) was identified. During two weeks, there was a positive correlation of transthyretin with plasma selenium (r = 0.71; p = 0.05) regardless of the CRP values. Transthyretin may have reflected plasma selenium, mainly because the correlation was verified after the acute phase.

Selenium Enrichment of Horticultural Crops.

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Puccinelli, Martina; Malorgio, Fernando; Pezzarossa, Beatrice

2017-06-04

The ability of some crops to accumulate selenium (Se) is crucial for human nutrition and health. Selenium has been identified as a cofactor of the enzyme glutathione peroxidase, which is a catalyzer in the reduction of peroxides that can damage cells and tissues, and can act as an antioxidant. Plants are the first link in the food chain, which ends with humans. Increasing the Se quantity in plant products, including leafy and fruity vegetables, and fruit crops, without exceeding the toxic threshold, is thus a good way to increase animal and human Se intake, with positive effects on long-term health. In many Se-enriched plants, most Se is in its major organic form. Given that this form is more available to humans and more efficient in increasing the selenium content than inorganic forms, the consumption of Se-enriched plants appears to be beneficial. An antioxidant effect of Se has been detected in Se-enriched vegetables and fruit crops due to an improved antioxidative status and to a reduced biosynthesis of ethylene, which is the hormone with a primary role in plant senescence and fruit ripening. This thus highlights the possible positive effect of Se in preserving a longer shelf-life and longer-lasting quality.

Selenium Enrichment of Horticultural Crops

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Martina Puccinelli

2017-06-01

Full Text Available The ability of some crops to accumulate selenium (Se is crucial for human nutrition and health. Selenium has been identified as a cofactor of the enzyme glutathione peroxidase, which is a catalyzer in the reduction of peroxides that can damage cells and tissues, and can act as an antioxidant. Plants are the first link in the food chain, which ends with humans. Increasing the Se quantity in plant products, including leafy and fruity vegetables, and fruit crops, without exceeding the toxic threshold, is thus a good way to increase animal and human Se intake, with positive effects on long-term health. In many Se-enriched plants, most Se is in its major organic form. Given that this form is more available to humans and more efficient in increasing the selenium content than inorganic forms, the consumption of Se-enriched plants appears to be beneficial. An antioxidant effect of Se has been detected in Se-enriched vegetables and fruit crops due to an improved antioxidative status and to a reduced biosynthesis of ethylene, which is the hormone with a primary role in plant senescence and fruit ripening. This thus highlights the possible positive effect of Se in preserving a longer shelf-life and longer-lasting quality.

The Evolving Role of Selenium in the Treatment of Graves' Disease and Ophthalmopathy

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Leonidas H. Duntas

2012-01-01

Full Text Available Graves' disease (GD and ophthalmopathy (GO are organ-specific autoimmune-inflammatory disorders characterized by a complex pathogenesis. The inflammatory process is dominated by an imbalance of the antioxidant-oxidant mechanism, increased production of radical oxygen species (ROS, and cytokines which sustain the autoimmune process and perpetuate the disease. Recently, selenium, which is a powerful antioxidant, has been successfully applied in patients with mild GO, slowing the progression of disease, decreasing the clinical activity score, and appreciably improving the quality of life. The mechanisms of selenium action are variable. The aim of this review is to summarize the actions of selenium in GD and GO. Selenium as selenocysteine is incorporated in selenoproteins, such as glutathione peroxidase which catalyzes the degradation of hydrogen peroxide and lipid hydroperoxide that are increasingly produced in hyperthyroidism. Moreover, selenium decreases the formation of proinflammatory cytokines, while it contributes, in synergy with antithyroid drugs, to stabilization of the autoimmune process in GD and alleviation of GO. It is now to be clarified whether enforced nutritional supplementation has the same results and whether prolonging selenium administration may have an impact on the prevention of disease.

Selenopeptides and elemental selenium in Thunbergia alata after exposure to selenite: quantification method for elemental selenium.

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Aborode, Fatai Adigun; Raab, Andrea; Foster, Simon; Lombi, Enzo; Maher, William; Krupp, Eva M; Feldmann, Joerg

2015-07-01

Three month old Thunbergia alata were exposed for 13 days to 10 μM selenite to determine the biotransformation of selenite in their roots. Selenium in formic acid extracts (80 ± 3%) was present as selenopeptides with Se-S bonds and selenium-PC complexes (selenocysteinyl-2-3-dihydroxypropionyl-glutathione, seleno-phytochelatin2, seleno-di-glutathione). An analytical method using HPLC-ICPMS to detect and quantify elemental selenium in roots of T. alata plants using sodium sulfite to quantitatively transform elemental selenium to selenosulfate was also developed. Elemental selenium was determined as 18 ± 4% of the total selenium in the roots which was equivalent to the selenium not extracted using formic acid extraction. The results are in an agreement with the XAS measurements of the exposed roots which showed no occurrence of selenite or selenate but a mixture of selenocysteine and elemental selenium.

Selenium alleviates cadmium toxicity by preventing oxidative stress in sunflower (Helianthus annuus) seedlings.

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Saidi, Issam; Chtourou, Yacine; Djebali, Wahbi

2014-03-01

The present study investigated the possible mediatory role of selenium (Se) in protecting plants from cadmium (Cd) toxicity. The exposure of sunflower seedlings to 20μM Cd inhibited biomass production, decreased chlorophyll and carotenoid concentrations and strongly increased accumulation of Cd in both roots and shoots. Similarly, Cd enhanced hydrogen peroxides content and lipid peroxidation as indicated by malondialdehyde accumulation. Pre-soaking seeds with Se (5, 10 and 20μM) alleviated the negative effect of Cd on growth and led to a decrease in oxidative injuries caused by Cd. Furthermore, Se enhanced the activities of catalase, ascorbate peroxidase and glutathione reductase, but lowered that of superoxide dismutase and guaiacol peroxidase. As important antioxidants, ascorbate and glutathione contents in sunflower leaves exposed to Cd were significantly decreased by Se treatment. The data suggest that the beneficial effect of Se during an earlier growth period could be related to avoidance of cumulative damage upon exposure to Cd, thus reducing the negative consequences of oxidative stress caused by heavy metal toxicity. Copyright © 2013 Elsevier GmbH. All rights reserved.

Activity of glutathione peroxidase (GGSH-Px) in the blood of ewes and their lambs receiving the selenium-enriched unicellular alga Chlorella

Czech Academy of Sciences Publication Activity Database

Trávníček, J.; Racek, J.; Trefil, L.; Rodinová, H.; Kroupová, V.; Illek, J.; Doucha, Jiří; Písek, L.

2008-01-01

Roč. 53, č. 7 (2008), s. 292-298 ISSN 1212-1819 Institutional research plan: CEZ:AV0Z50200510 Keywords : selenite * organic selenium * blood selenium Subject RIV: EE - Microbiology, Virology Impact factor: 0.735, year: 2008

Transmutation of human glutathione transferase A2-2 with peroxidase activity into an efficient steroid isomerase.

Science.gov (United States)

Pettersson, Par L; Johansson, Ann-Sofie; Mannervik, Bengt

2002-08-16

A major goal in protein engineering is the tailor-making of enzymes for specified chemical reactions. Successful attempts have frequently been based on directed molecular evolution involving libraries of random mutants in which variants with desired properties were identified. For the engineering of enzymes with novel functions, it would be of great value if the necessary changes of the active site could be predicted and implemented. Such attempts based on the comparison of similar structures with different substrate selectivities have previously met with limited success. However, the present work shows that the knowledge-based redesign restricted to substrate-binding residues in human glutathione transferase A2-2 can introduce high steroid double-bond isomerase activity into the enzyme originally characterized by glutathione peroxidase activity. Both the catalytic center activity (k(cat)) and catalytic efficiency (k(cat)/K(m)) match the values of the naturally evolved glutathione transferase A3-3, the most active steroid isomerase known in human tissues. The substrate selectivity of the mutated glutathione transferase was changed 7000-fold by five point mutations. This example demonstrates the functional plasticity of the glutathione transferase scaffold as well as the potential of rational active-site directed mutagenesis as a complement to DNA shuffling and other stochastic methods for the redesign of proteins with novel functions.

Effect of cholesterol feeding on tissue lipid perioxidation, glutathione peroxidase activity and liver microsomal functions in rats and guinea pigs

NARCIS (Netherlands)

TSAI, A. C.; THIE, G. M.; Lin, C. R.

1977-01-01

The effect of cholesterol feeding on liver and aortic nonenzymatic lipid peroxidation and glutathione peroxidase activities, and on liver microsomal NADPH-dependent lipid peroxidation, codeine hydroxylation and cytochrome P-450 levels was examined in rats and guinea pigs. One percent cholesterol was

Hepatic glutathione and glutathione S-transferase in selenium deficiency and toxicity in the chick

International Nuclear Information System (INIS)

Kim, Y. S.

1989-01-01

First, the hepatic activity of GSH-T CDNB was increased only under conditions of severe oxidative stress produced by combined Se- and vitamin E (VE)-deficiency, indicating that VE also affects GSH metabolism. Second, the incorporation of 35 S-methionine into GSH and protein was about 4- and 2-fold higher, respectively, in Se- and VE-deficient chick hepatocytes as compared to controls. Third, chicks injected with the glutathione peroxidase (SeGSHpx) inhibitor, aurothioglucose (AuTG), showed increase hepatic GSH-T CDNB activity and plasma GSH concentration regardless of their Se status. Fourth, the effect of ascorbic acid (AA), on GSH metabolism was studied. Chicks fed 1000 ppm AA showed decreased hepatic GSH concentration compared to chicks fed no AA in a Se- and VE-deficient diet. Fifth, chicks fed excess Se showed increase hepatic activity of GSH-T CDNB and GSH concentration regardless of VE status

Analyses of Selenotranscriptomes and Selenium Concentrations in Response to Dietary Selenium Deficiency and Age Reveal Common and Distinct Patterns by Tissue and Sex in Telomere-Dysfunctional Mice.

Science.gov (United States)

Cao, Lei; Zhang, Li; Zeng, Huawei; Wu, Ryan Ty; Wu, Tung-Lung; Cheng, Wen-Hsing

2017-10-01

Background: The hierarchies of tissue selenium distribution and selenotranscriptomes are thought to critically affect healthspan and longevity. Objective: We determined selenium status and selenotranscriptomes in response to long-term dietary selenium deficiency and age in tissues of male and female mice. Methods: Weanling telomerase RNA component knockout C57BL/6 mice were fed a selenium-deficient (0.03 mg Se/kg) Torula yeast-based AIN-93G diet or a diet supplemented with sodium selenate (0.15 mg Se/kg) until age 18 or 24 mo. Plasma, hearts, kidneys, livers, and testes were collected to assay for selenotranscriptomes, selected selenoproteins, and tissue selenium concentrations. Data were analyzed with the use of 2-factor ANOVA (diet × age) in both sexes. Results: Dietary selenium deficiency decreased ( P ≤ 0.05) selenium concentrations (65-72%) and glutathione peroxidase (GPX) 3 (82-94%) and selenoprotein P (SELENOP) (17-41%) levels in the plasma of both sexes of mice and mRNA levels (9-68%) of 4, 4, and 12 selenoproteins in the heart, kidney, and liver of males, respectively, and 5, 16, and 14 selenoproteins, respectively, in females. Age increased selenium concentrations and SELENOP levels (27% and 30%, respectively; P ≤ 0.05) in the plasma of males only but decreased (12-46%; P selenium deficiency and age in ≥1 tissue or sex, or both. Dietary selenium deficiency upregulated (40-160%; P ≤ 0.05) iodothyronine deiodinase 2 ( Dio2 ) and selenoprotein N ( Selenon ) in the kidneys of males. Age upregulated (11-44%; P selenium status and selenotranscriptomes because of dietary selenium deficiency and age. © 2017 American Society for Nutrition.

Antioxidant capacity of meagre (Argyrossomus regius fed different lipid content and source, with and without selenium

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Sthelio Braga Fonseca

2014-06-01

Meagre (600 animals were kept in 24 tanks (80 L with constant renovation and aeration and maintained at 20.7 ± 0.7ºC and oxygen 8.8 ± 1.7 mg L-1. Fish were fed twice per day, six days per week, with eight different experimental diets for 60 days. Diets were formulated to have two different oil sources (fish or vegetable blend oils with 45% of linseed, 35% of rapeseed and 20% of soybean oil, two lipid levels (12 and 17% and two selenium supplementation (0 and 1 mg/kg diet. Lipid peroxidation (LPO, glutathione reductase (GR, glutathione peroxidase (GPx, total glutathione (TG and catalase (CAT were analyzed in liver of fish. CAT, GPx and GR activities were not significantly altered in fish fed with diets with different oil sources. However, TG in fish fed with fish oil diet was higher than the levels observed in fish fed with vegetable blend oil. Furthermore, fish fed with fish oil diet showed lower lipid peroxidation when compared with fish fed vegetable blend oil diet (Table 1. Concerning the oil level in diet, it was observed that fish fed with a diet of 17% lipids had a higher level of total glutathione when compared to fish fed with a diet of 12% lipids. On the other hand, the fish fed with a diet with 12% lipids showed lower levels of lipid peroxidation when compared to fish fed with a diet of 17% lipids. Fish fed with diets supplemented with selenium showed a significantly increased activity of GPx when compared with fish fed without selenium. Three-way ANOVA analysis showed that dietary lipid level and the presence of selenium have a significant interaction on the activities of CAT and GR, as well as, levels of TG and LPO. A significant interaction between the source of oil and the presence of selenium on GR activities was observed. Interaction on source and level was observed to CAT. In conclusion, the antioxidant capacity of meagre is influenced by the source of oil, the level of lipids and the presence of selenium in their diet.

Biogenesis of Selenium Nanoparticles Using Green Chemistry.

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Shoeibi, Sara; Mozdziak, Paul; Golkar-Narenji, Afsaneh

2017-11-09

Selenium binds some enzymes such as glutathione peroxidase and thioredoxin reductase, which may be activated in biological infections and oxidative stress. Chemical and physical methods for synthesizing nanoparticles, apart from being expensive, have their own particular risks. However, nanoparticle synthesis through green chemistry is a safe procedure that different biological sources such as bacteria, fungi, yeasts, algae and plants can be the catalyst bed for processing. Synthesis of selenium nanoparticles (SeNPs) by macro/microorganisms causes variation in morphology and shape of the particles is due to diversity of reduction enzymes in organisms. Reducing enzymes of microorganisms by changing the status of redox convert metal ions (Se 2- ) to SeNPs without charge (Se 0 ). Biological activity of SeNPs includes their protective role against DNA oxidation. Because of the biological and industrial properties, SeNPs have wide applications in the fields of medicine, microelectronic, agriculture and animal husbandry. SeNPs can show strong antimicrobial effects on the growth and proliferation of microorganisms in a dose-dependent manner. The objective of this review is to consider SeNPs applications to various organisms.

Features of selenium metabolism in humans living under the conditions of North European Russia.

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Parshukova, Olga; Potolitsyna, Natalya; Shadrina, Vera; Chernykh, Aleksei; Bojko, Evgeny

2014-08-01

Selenium supplementation and its effects on Northerners have been little studied. The aim of our study was to assess the selenium levels of the inhabitants of North European Russia, the seasonal aspects of selenium supplementation, and the interrelationships between selenium levels and the levels of thyroid gland hormones. To study the particular features of selenium metabolism in Northerners over the course of 1 year, 19 healthy male Caucasian volunteers (18-21 years old) were recruited for the present study. The subjects were military guards in a Northern European region of Russia (Syktyvkar, Russia, 62°N latitude) who spent 6-10-h outdoors daily. The study was conducted over a 12-month period. Selenium levels, glutathione peroxidase (GP) activity, as well as total triiodothyronine (T3), total thyroxin (T4), free thyroxin, free triiodothyronine, and thyrotropin (TSH) levels, were determined in the blood serum. The study subjects showed low levels of plasma selenium throughout the year. We observed a noticeable decrease in plasma selenium levels during the period from May to August, with the lowest levels in July. Selenium levels in the military guards correlated with the levels of selenium-dependent GP enzyme activity throughout the year. Additionally, we demonstrated a significant correlation between selenium and pituitary-thyroid axis hormones (total T3, free T4, and TSH) in periods in which plasma selenium levels were lower than the established normal ranges. Over the course of 1 year, low levels of plasma selenium affect GP activity and thyroid hormone levels in humans living in North European Russia.

Dietary supplementation with selenium yeast and tea polyphenols improve growth performance and nitrite tolerance of Wuchang bream (Megalobrama amblycephala).

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Long, Meng; Lin, Wang; Hou, Jie; Guo, Honghui; Li, Li; Li, Dapeng; Tang, Rong; Yang, Fan

2017-09-01

In order to explore the effects of dietary selenium yeast, tea polyphenols and their combination on growth of Wuchang bream (Megalobrama amblycephala) and its resistance to nitrite stress, 360 healthy Wuchang bream with initial body weight of (55.90 ± 2.60) g were randomly divided into four groups: a control group fed with basal diet and three treated groups fed with basal diets supplemented with 0.50 mg/kg selenium yeast, 50 mg/kg tea polyphenols, and the combination of 0.50 mg/kg selenium yeast and 50 mg/kg tea polyphenols, respectively. After 60 d of feeding, the growth performance of Wuchang bream was measured. Then 25 fish per tank were exposed to nitrite stress of 15.0 mg/L. The serum stress hormones, liver histology and hepatic antioxidant responses were evaluated before nitrite exposure (0 h) and at 6, 12, 24, 48 and 96 h after exposure. The results showed that before nitrite exposure, compared with the control, the weight gain, specific growth rate, liver total antioxidant capacity, the activities and transcriptional levels of hepatic antioxidant enzymes (superoxide dismutase and glutathione peroxidase) in the selenium yeast and combination groups were significantly increased, while feed conversion rate was decreased significantly, which suggested that the combined use of selenium yeast and tea polyphenols as well as the single selenium yeast supplementation improved growth performance and enhanced antioxidant capacity in fish. After nitrite exposure, compared with the control, liver total antioxidant capacity as well as the activities and transcription levels of catalase superoxide dismutase and glutathione peroxidase in three treatment groups were significantly increased in varying degrees whereas serum cortisol contents and liver malondialdehyde levels were decreased significantly. By contrast, the combined use of selenium yeast and tea polyphenols was more effective than the single supplementation with selenium yeast or tea polyphenols. In

Effects of polymorphisms in vitamin E-, vitamin C-, and glutathione peroxidase-related genes on serum biomarkers and associations with glaucoma

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To study the association of selected polymorphism in genes related to vitamin E, vitamin C, and glutathione peroxidase with these biomarkers and primary open-angle glaucoma (POAG) risk. A case-control study matched for age, sex, and bodyweight was undertaken. Two hundred fifty POAG cases and 250 con...

Comparison of the redox chemistry of sulfur- and selenium-containing analogs of uracil✰

Science.gov (United States)

Payne, N. Connor; Geissler, Andrew; Button, Aileen; Sasuclark, Alexandru R.; Schroll, Alayne L.; Ruggles, Erik L.; Gladyshev, Vadim N.; Hondal, Robert J.

2017-01-01

Selenium is present in proteins in the form of selenocysteine, where this amino acid serves catalytic oxidoreductase functions. The use of selenocysteine in nature is strongly associated with redox catalysis. However, selenium is also found in a 2-selenouridine moiety at the wobble position of tRNAGlu, tRNAGln and tRNALys. It is thought that the modifications of the wobble position of the tRNA improves the selectivity of the codon-anticodon pair as a result of the physico-chemical changes that result from substitution of sulfur and selenium for oxygen. Both selenocysteine and 2-selenouridine have widespread analogs, cysteine and thiouridine, where sulfur is used instead. To examine the role of selenium in 2-selenouridine, we comparatively analyzed the oxidation reactions of sulfur-containing 2-thiouracil-5-carboxylic acid (s2c5Ura) and its selenium analog 2-selenouracil-5-carboxylic acid (se2c5Ura) using 1H-NMR spectroscopy, 77Se-NMR spectroscopy, and liquid chromatography-mass spectrometry. Treatment of s2c5Ura with hydrogen peroxide led to oxidized intermediates, followed by irreversible desulfurization to form uracil-5-carboxylic acid (c5Ura). In contrast, se2c5Ura oxidation resulted in a diselenide intermediate, followed by conversion to the seleninic acid, both of which could be readily reduced by ascorbate and glutathione. Glutathione and ascorbate only minimally prevented desulfurization of s2c5Ura, whereas very little deselenization of se2c5Ura occurred in the presence of the same antioxidants. In addition, se2c5Ura but not s2c5Ura showed glutathione peroxidase activity, further suggesting that oxidation of se2c5Ura is readily reversible, while oxidation of s2c5Ura is not. The results of the study of these model nucleobases suggest that the use of 2-selenouridine is related to resistance to oxidative inactivation that otherwise characterizes 2-thiouridine. As the use of selenocysteine in proteins also confers resistance to oxidation, our findings suggest a

Comparison of the redox chemistry of sulfur- and selenium-containing analogs of uracil.

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Payne, N Connor; Geissler, Andrew; Button, Aileen; Sasuclark, Alexandru R; Schroll, Alayne L; Ruggles, Erik L; Gladyshev, Vadim N; Hondal, Robert J

2017-03-01

Selenium is present in proteins in the form of selenocysteine, where this amino acid serves catalytic oxidoreductase functions. The use of selenocysteine in nature is strongly associated with redox catalysis. However, selenium is also found in a 2-selenouridine moiety at the wobble position of tRNA Glu , tRNA Gln and tRNA Lys . It is thought that the modifications of the wobble position of the tRNA improves the selectivity of the codon-anticodon pair as a result of the physico-chemical changes that result from substitution of sulfur and selenium for oxygen. Both selenocysteine and 2-selenouridine have widespread analogs, cysteine and thiouridine, where sulfur is used instead. To examine the role of selenium in 2-selenouridine, we comparatively analyzed the oxidation reactions of sulfur-containing 2-thiouracil-5-carboxylic acid (s 2 c 5 Ura) and its selenium analog 2-selenouracil-5-carboxylic acid (se 2 c 5 Ura) using 1 H-NMR spectroscopy, 77 Se-NMR spectroscopy, and liquid chromatography-mass spectrometry. Treatment of s 2 c 5 Ura with hydrogen peroxide led to oxidized intermediates, followed by irreversible desulfurization to form uracil-5-carboxylic acid (c 5 Ura). In contrast, se 2 c 5 Ura oxidation resulted in a diselenide intermediate, followed by conversion to the seleninic acid, both of which could be readily reduced by ascorbate and glutathione. Glutathione and ascorbate only minimally prevented desulfurization of s 2 c 5 Ura, whereas very little deselenization of se 2 c 5 Ura occurred in the presence of the same antioxidants. In addition, se 2 c 5 Ura but not s 2 c 5 Ura showed glutathione peroxidase activity, further suggesting that oxidation of se 2 c 5 Ura is readily reversible, while oxidation of s 2 c 5 Ura is not. The results of the study of these model nucleobases suggest that the use of 2-selenouridine is related to resistance to oxidative inactivation that otherwise characterizes 2-thiouridine. As the use of selenocysteine in proteins also confers

Optimised selenium enrichment of Artemia sp. feed to improve red drum (Sciaenops ocellatus) larvae rearing.

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Juhász, Péter; Lengyel, Szvetlana; Udvari, Zsolt; Sándor, Alex Nagy; Stündl, László

2017-09-01

Selenium is an essential microelement for the normal functioning of life processes. Moreover, it is a component of enzymes with antioxidant effects. However, it has the smallest window of any micronutrient between requirement and toxicity. Selenium is a regularly used element in fish feeds; moreover, enriching zooplankton with selenium to rear larvae is also a well-known technology. It is accepted that the most common starter foods of fish larvae, natural rotifers contain the smallest dosage of selenium, but providing selenium enriched Artemia sp. instead could increase survival and growth rate of fish. However, no such references are available for the red drum (Sciaenops ocellatus) larvae. Therefore, in this study, Artemia sp. was enriched with nano-selenium of verified low toxicity and easy availability in 5 treatments (1, 5, 10, 50, 100 mg/l Se), and then, fish larvae were fed with four of these enriched Artemia stocks (1, 5, 10, 50 mg/l Se) and a control group. At the end of the 9-day-long experiment, survival rate (S) and growth parameters (SL, W, K-factor, SGR) of fish larvae were calculated as well as their selenium retention and glutathione peroxidase enzyme activity were analysed. It was revealed that a moderate level of selenium enrichment (~4 mg/kg dry matter) of Artemia sp. positively influences the rearing efficiency (i.e. survival and growth) of fish larvae, but higher dosages of selenium could cause adverse effects.

Selenium Supplementation does not Decrease Thyroid Peroxidase Antibody Concentration in Children and Adolescents with Autoimmune Thyroiditis

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W. Bonfig

2010-01-01

Full Text Available In adults, selenium supplementation decreases thyroid peroxidase antibody (TPO Ab concentrations in patients with autoimmune thyroiditis (AIT. Our aim in this study was to investigate if selenium supplementation decreased TPO Ab and thyroglobulin antibody (Tg Ab concentrations in children with AIT. Forty-nine patients (33 females with newly diagnosed AIT and hypothyroidism were randomized to daily oral therapy with levothyroxine alone (group A, n = 18, levothyroxine plus 100 µg sodium-selenite (group B, n = 13, or levothyroxine plus 200 µg sodium-selenite (group C, n = 18. Mean age at diagnosis was 12.2 ± 2.2 years. All 49 patients needed a mean levothyroxine dose of 1.6 ± 0.5 µg/kg body weight to lower TSH to the treatment goal of 1–2 µU/ml, with no significant difference between groups. At study entry and after 12 months, TPO Ab concentrations were comparable in all three groups. Tg Ab concentrations decreased significantly after 12 months in group A and group C (p = 0.03 and p = 0.01, but not in group B (p = 0.06. It is our conclusion that selenium supplementation with sodium-selenite does not decrease TPO Ab concentrations in children and adolescents, neither given in the reduced dose of 100 µg daily nor given in the “adult” supplementation dose of 200 µg daily.

EFFECT OF SELENIUM SUPPLEMENTATION ON PIG PRODUCTION PROPERTIES, ANTIOXIDANT STATUS AND MEAT QUALITY

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Tomislav Šperanda

2013-12-01

Full Text Available Food containing functional ingredients to achieve a positive effect on health and reducing the risk of infection is increasing production. It is also very important to improve the quality of pork with respect to change the genetic makeup of pigs that raised leanness, being inversely correlated with the quality of meat. This study monitored the effectiveness of addition of higher doses of organic selenium in the diet of fattening pigs in relation to their growth, immunity, antioxidant power, the quality of meat and possibility of meat enriching with selenium. The experiment was carried out on 100 pigs (crossbred WJxSLxP of both sexes, from 28 kg to 98 kg body weight during a period of 98 days. Piglets fed the finished feed mixture for fattening up to 60 kg (ST-1 and a mixture for fattening up to 100 kg (DM-2 in addition, by the groups as follows: K-0. 3 mg/kg organic selenium, P1-0.5 mg/kg inorganic selenium, P2-0.5 mg/kg organic selenium, P3-0.5 mg/ kg organic selenium +0.2% zeolite clinoptilolite treated vibrotehnology and P4-gradual increase in selenium so that the concentration of the last month was 0.7 mg/ kg diet of organic selenium. All groups of pigs fed high concentration of organic selenium had a higher proportion of lymphocytes, especially CD4 T lymphocytes. Glutathione peroxidase activity was higher in all groups fed elevated selenium levels and significantly higher in the P3 and P4 groups 71st and 98th days of the trials. Glutathione reductase was significantly higher in the P3 and P4 group 98th days compared to the control. Antioxidant indicators suggested increased antioxidant protection in groups supplemented with 0.5 ppm organic selenium and selenium formulations of the same with the addition of zeolite under stress intensive pig production. No differences were found in the products of lipid peroxidation (TBARS in raw meat or in meat after a week in refrigerator storage. By histological examination statistically higher level of

Effect of selenium on the thyroid gland antioxidative metabolisms in rat model by ionizing radiation

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Choi, Hyung Seok; Choi, Jun Hyeok; JUng, Do Young; Kim, Jang Oh; Shin, Ji Hye; Min, Byung In [Inje University, Gimhae (Korea, Republic of)

2017-03-15

Selenium (Se), which is natural materials existing was known as an important component of selenoprotein, one of the important proteins responsible for the redox pump of a living body. Selenium was orally administered to Rat and irradiated with 10 Gy of radiation. Then, the thyroid gland was used as a target organ for 1 day, 7 days and 21 days to investigate the radiation protection effect of selenium (Se) through changes of blood components, thyroid hormones (T3, T4), antioxidant enzyme (GPx) activity and thyroid tissue changes. As a result, there was a significant protective effect of hematopoietic immune system(hemoglobin concentration, neutrophil, platelet)(p<0.05). The activity of Glutathione Peroxidase (GPx), the antioxidant enzyme, and the activity of the target organ, thyroid hormone (T3, T4), also showed significant activity changes (p<0.05). In the observation of tissue changes, it was confirmed that there was a protective effect of thyroid cell damage which caused the cell necrosis by radiation treatment. Therefore, it is considered that selenium(Se) can be utilized as a radiation defense agent by inducing immunogenic activity effect of a living body.

The effect of EGb 761 on retinal lipid peroxidation and glutathione peroxidase level in experimental lens induced uveitis.

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Bilgihan, A; Aricioğlu, A; Bilgihan, K; Onol, M; Hasanreisoğlu, B; Türközkan, N

1994-01-01

An acute lens-induced necrotizing intraocular inflammation was produced in pigmented guinea pigs. Treatment of these animals by 100 mg/kg/day EGb 761 a free oxygen radical scavenger for 10 days, reduced retinal lipid peroxidation (p > 0.05) and increased the retinal glutathione peroxidase level (p > 0.05). Although not significantly, these findings suggest that EGb 761 could be combined with other antiinflammatory drugs and may be beneficial in the treatment of uveitis.

Selenium bioavailability from naturally produced high-selenium peas and oats in selenium-deficient rats.

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Yan, Lin; Johnson, LuAnn K

2011-06-08

This study determined the bioavailability of selenium (Se) from yellow peas and oats harvested from the high-Se soil of South Dakota, United States. The Se concentrations were 13.5 ± 0.2 and 2.5 ± 0.1 mg/kg (dry weight) for peas and oats, respectively. Male weanling Sprague-Dawley rats were depleted of Se by feeding them a 30% Torula yeast-based diet (4.1 μg Se/kg) for 56 days, and then they were replenished with Se for an additional 50 days by feeding them the same diet supplemented with 20, 30, or 40 μg Se/kg from peas or oats, respectively. Selenium bioavailability was determined on the basis of the restoration of Se-dependent enzyme activities and tissue Se concentrations in Se-depleted rats, comparing those responses for yellow peas and oats to those for l-selenomethionine (SeMet; used as a reference) by using a slope-ratio method. Dietary supplementation with peas or oats resulted in linear or log-linear, dose-dependent increases in glutathione peroxidase activities in blood and liver and in thioredoxin reductase activity in liver. Supplementation with peas or oats resulted in linear or log-linear, dose-dependent increases in Se concentrations of plasma, liver, gastrocnemius muscle, and kidneys. The overall bioavailability was approximately 88% for Se from yellow peas and 92% from oats, compared to SeMet. It was concluded that Se from naturally produced high-Se yellow peas or oats is highly bioavailable in this model and that these high-Se foods may be a good dietary source of Se.

Glutathione peroxidases of the potato cyst nematode Globodera Rostochiensis.

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Jones, J T; Reavy, B; Smant, G; Prior, A E

2004-01-07

We report the cloning and characterisation of full-length DNAs complementary to RNA (cDNAs) encoding two glutathione peroxidases (GpXs) from a plant parasitic nematode, the potato cyst nematode (PCN) Globodera rostochiensis. One protein has a functional signal peptide that targets the protein for secretion from animal cells while the other is predicted to be intracellular. Both genes are expressed in all parasite stages tested. The mRNA encoding the intracellular GpX is present throughout the nematode second stage juvenile and is particularly abundant in metabolically active tissues including the genital primordia. The mRNA encoding the secreted GpX is restricted to the hypodermis, the outermost cellular layer of the nematode, a location from which it is likely to be secreted to the parasite surface. Biochemical studies confirmed the secreted protein as a functional GpX and showed that, like secreted GpXs of other parasitic nematodes, it does not metabolise hydrogen peroxide but has a preference for larger hydroperoxide substrates. The intracellular protein is likely to have a role in metabolism of active oxygen species derived from internal body metabolism while the secreted protein may protect the parasite from host defences. Other functional roles for this protein are discussed.

Selenium toxicity: cause and effects in aquatic birds

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Spallholz, J.E.; Hoffman, D.J.

2002-01-01

There are several manners in which selenium may express its toxicity: (1) an important mechanism appears to involve the formation of CH3Se- which either enters a redox cycle and generates superoxide and oxidative stress, or forms free radicals that bind to and inhibit important enzymes and proteins. (2) Excess selenium as selenocysteine results in inhibition of selenium methylation metabolism. As a consequence, concentrations of hydrogen selenide, an intermediate metabolite, accumulate in animals and are hepatotoxic, possibly causing other selenium-related adverse effects. (3) It is also possible that the presence of excess selenium analogs of sulfur-containing enzymes and structural proteins play a role in avian teratogenesis. l-selenomethionine is the most likely major dietary form of selenium encountered by aquatic birds, with lesser amounts of l-selenocysteine ingested from aquatic animal foods. The literature is suggestive that l-selenomethionine is not any more toxic to adult birds than other animals. l-Selenomethionine accumulates in tissue protein of adult birds and in the protein of egg white as would be expected to occur in animals. There is no suggestion from the literature that the levels of l-selenomethionine that would be expected to accumulate in eggs in the absence of environmental concentration of selenium pose harm to the developing embryo. For several species of aquatic birds, levels of Se as selenomethionine in the egg above 3 ppm on a wet weight basis result in reduced hatchability and deformed embryos. The toxicity of l-selenomethionine injected directly into eggs is greater than that found from the entry of l-selenomethionine into the egg from the normal adult diet. This suggests that there is unusual if not abnormal metabolism of l-selenomethionine in the embryo not seen when l-selenomethionine is present in egg white protein where it likely serves as a source of selenium for glutathione peroxidase synthesis in the developing aquatic chick.

Application of instrumental neutron activation analysis to assess dietary intake of selenium in Korean adults from meat and eggs

International Nuclear Information System (INIS)

Moon, Jong-Hwa; Kim, Sun-Ha; Chung, Yong-Sam; Lee, Ok-Hee

2013-01-01

Selenium is a key constituent of enzyme in glutathione peroxidase, which is effective in decreasing various types of oxidative stress, Thus, the adequacy of selenium intake is very important in decreasing the risks of various degenerating diseases such as cardiovascular disease, or certain cancers. Lately, the intake of animal foods is increasing among Koreans owing to a dietary transition toward a western style. This study was conducted to measure the selenium content in meat and eggs, and then assessed the selenium intake from these foods. Forty frequently eaten items among meat and eggs were analyzed using an Instrumental Neutron Activation Analysis. The selenium content in 100g of raw meat and eggs ranged from 8.1ug to 50.9ug. In particular, 100g of beef contained 12.4ug to 50.9ug of selenium; pork, 11.2ug to 22.6ug chicken, 10.2ug to 13.7ug and eggs, 28.6ug to 43.0ug. Thus, beef viscera and chicken eggs contain the highest amounts of selenium among these groups. 100g of Pork belly, the most frequently eaten meat type among Koreans, contains 14.6ug of selenium. An evaluation of dietary selenium intake shows that the total selenium supply from meats and eggs was 28.4ug/day and 27.5 ug/day in adult men and women, respectively. These are over one-half of the Korean RNI (Recommended Daily Intake) of 55ug/day. (author)

Effects of Selenium Yeast on Blood Glucose and Antioxidant Biomarkers in Cholesterol Fed Diet Induced Type 2 Diabetes Mellitus in Wistar Rats.

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Tanko, Y; Jimoh, A; Ahmed, A; Adam, A; Ejeh, L; Mohammed, A; Ayo, J O

2017-03-06

Selenium is an antioxidant that prevents oxygen radical from damaging cells from chronic diseases that can develop from cell injury and inflammation such as diabetes mellitus. The aim of the study is to investigate the possible protective effect of selenium yeast on cholesterol diet induced type-2 diabetes mellitus and oxidative stress in rats. Twenty male wistar rats were divided in to four groups of five animals each: Group 1: (Negative control) received standard animal feed only, Group 2:  received cholesterol diet (CD) only, Group 3: received CD and 0.1 mg/kg selenium yeast orally, Group 4: Received CD and 0.2 mg/kg selenium yeast orally for six weeks. At the end of the study period, the animals were sacrificed and the serum samples were collected and evaluated for estimation of antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx). The results showed a significant decrease in blood glucose level in the groups  co-administered CD and selenium yeast when compared to CD group only. Antioxidant enzymes status recorded significant decrease in SOD, CAT and GPx activities in CD and selenium yeast administered when compared to CD group only. In Conclusion, Selenium yeast administrations prevent free radical formations which are potent inducer of diabetes mellitus.

Ablation of ferroptosis regulator glutathione peroxidase 4 in forebrain neurons promotes cognitive impairment and neurodegeneration

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William Sealy Hambright

2017-08-01

Full Text Available Synaptic loss and neuron death are the underlying cause of neurodegenerative diseases such as Alzheimer's disease (AD; however, the modalities of cell death in those diseases remain unclear. Ferroptosis, a newly identified oxidative cell death mechanism triggered by massive lipid peroxidation, is implicated in the degeneration of neurons populations such as spinal motor neurons and midbrain neurons. Here, we investigated whether neurons in forebrain regions (cerebral cortex and hippocampus that are severely afflicted in AD patients might be vulnerable to ferroptosis. To this end, we generated Gpx4BIKO mouse, a mouse model with conditional deletion in forebrain neurons of glutathione peroxidase 4 (Gpx4, a key regulator of ferroptosis, and showed that treatment with tamoxifen led to deletion of Gpx4 primarily in forebrain neurons of adult Gpx4BIKO mice. Starting at 12 weeks after tamoxifen treatment, Gpx4BIKO mice exhibited significant deficits in spatial learning and memory function versus Control mice as determined by the Morris water maze task. Further examinations revealed that the cognitively impaired Gpx4BIKO mice exhibited hippocampal neurodegeneration. Notably, markers associated with ferroptosis, such as elevated lipid peroxidation, ERK activation and augmented neuroinflammation, were observed in Gpx4BIKO mice. We also showed that Gpx4BIKO mice fed a diet deficient in vitamin E, a lipid soluble antioxidant with anti-ferroptosis activity, had an expedited rate of hippocampal neurodegeneration and behavior dysfunction, and that treatment with a small-molecule ferroptosis inhibitor ameliorated neurodegeneration in those mice. Taken together, our results indicate that forebrain neurons are susceptible to ferroptosis, suggesting that ferroptosis may be an important neurodegenerative mechanism in diseases such as AD. Keywords: Ferroptosis, Neurodegeneration, Cognitive impairment, Alzheimer's disease, Glutathione peroxidase 4, Transgenic mice

Delineating hierarchy of selenotranscriptome expression and their response to selenium status in chicken central nervous system.

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Jiang, Xiu-Qing; Cao, Chang-Yu; Li, Zhao-Yang; Li, Wei; Zhang, Cong; Lin, Jia; Li, Xue-Nan; Li, Jing-Long

2017-04-01

Selenium (Se) incorporated in selenoproteins as selenocysteine and supports various important cellular and organismal functions. We recently reported that chicken brain exhibited high priority for Se supply and retention under conditions of dietary Se deficiency and supernutrition Li et al. (2012) . However, the selenotranscriptome expressions and their response to Se status in chicken central nervous system (CNS) are unclear. To better understand the relationship of Se homeostasis and selenoproteins expression in chicken CNS, 1day-old HyLine White chickens were fed a low Se diet (Se-L, 0.028mg/g) supplemented with 4 levels of dietary Se (0 to 5.0mgSe/kg) as Na 2 SeO 3 for 8weeks. Then chickens were dissected for getting the CNS, which included cerebral cortex, cerebellum, thalamus, bulbus cinereus and marrow. The expressions of selenoproteome which have 24 selenoproteins were detected by the quantitative real-time PCR array. The concept of a selenoprotein hierarchy was developed and the hierarchy of different regions in chicken CNS was existence, especially cerebral cortex and bulbus cinereus. The expression of selenoproteins has a hierarch while changing Se content, and Selenoprotein T (Selt), Selenoprotein K (Selk), Selenoprotein W (Selw), Selenoprotein U (Selu), Glutathione peroxidase 3 (Gpx3), Glutathione peroxidase 4 (Gpx4), Selenoprotein P (Sepp1), Selenoprotein O (Selo), Selenoprotein 15 (Sel15), Selenoprotein N (Seln), Glutathione peroxidase 2 (Gpx2) and Selenoprotein P 2 (Sepp2) take more necessary function in the chicken CNS. Therefore, we hypothesize that hierarchy of regulated the transcriptions of selenoproteome makes an important role of CNS Se metabolism and transport in birds. Copyright © 2017 Elsevier Inc. All rights reserved.

Selenium level in the environment and the population of Zhoukoudian area, Beijing, China

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Li Na [Department of Epidemiology and Biostatistics, Peking University Health Science Center, 38 Xue Yuan Road, Hai, Dian District, Beijing 100083 (China); Gao Zhidong [Department of Epidemiology and Biostatistics, Peking University Health Science Center, 38 Xue Yuan Road, Hai, Dian District, Beijing 100083 (China); Luo Degang [Department of Epidemiology and Biostatistics, Peking University Health Science Center, 38 Xue Yuan Road, Hai, Dian District, Beijing 100083 (China); Tang Xun [Department of Epidemiology and Biostatistics, Peking University Health Science Center, 38 Xue Yuan Road, Hai, Dian District, Beijing 100083 (China); Chen Dafang [Department of Epidemiology and Biostatistics, Peking University Health Science Center, 38 Xue Yuan Road, Hai, Dian District, Beijing 100083 (China); Hu Yonghua [Department of Epidemiology and Biostatistics, Peking University Health Science Center, 38 Xue Yuan Road, Hai, Dian District, Beijing 100083 (China)]. E-mail: yhhu@bjmu.edu.cn

2007-08-01

The objective of this study was to detect the selenium level in the environment and the population of Zhoukoudian area, Beijing, and to discuss the influence of various factors on serum selenium level. The soil, drinking water, and foodstuff samples and venous blood samples of 401 individuals were obtained to determine the selenium level by gas chromatograph equipped with a {sup 63}Ni electron capture detector (ECD). The selenium level was 0.210 {+-} 0.013 {mu}g/g in soil, 0.017 {mu}g/L {+-} 0.002 in drinking water, 0.034 {+-} 0.002 {mu}g/g in rice, and 0.034 {+-} 0.012 {mu}g/g in wheat flour. This index showed that the Zhoukoudian area of Beijing was a moderate or marginal level selenium ecological landscape. The mean serum selenium level of the population was 75.01 {+-} 28.35 {mu}g/L, ranging between 35.2 and 160.4 {mu}g/L. A total of 279 (69.6%) individuals exhibited serum selenium level below 80 {mu}g/L, which is the lowest threshold for the activity of glutathione peroxidases (GPx) in vivo. A total of 35 (8.5%) individuals exhibited serum selenium level below 45 {mu}g/L. It is widely recommended that below this value (45 {mu}g/L) there is an increased risk of cardiovascular disease and cancer. Multiple linear regression analysis showed that serum selenium level was positively associated with body mass index ({beta} = 0.137; P = 0.011), serum total cholesterol TC ({beta} = 0.785; P = 0.000), however, negatively associated with systolic blood pressure ({beta} = - 0.172; P = 0.023), serum triglyceride ({beta} = - 0.170; P = 0.007), high density lipoprotein-cholesterol ({beta} = - 0.121; P = 0.027), and low high density lipoprotein-cholesterol ({beta} = - 0.568; P = 0.027)

Selenium level in the environment and the population of Zhoukoudian area, Beijing, China

International Nuclear Information System (INIS)

Li Na; Gao Zhidong; Luo Degang; Tang Xun; Chen Dafang; Hu Yonghua

2007-01-01

The objective of this study was to detect the selenium level in the environment and the population of Zhoukoudian area, Beijing, and to discuss the influence of various factors on serum selenium level. The soil, drinking water, and foodstuff samples and venous blood samples of 401 individuals were obtained to determine the selenium level by gas chromatograph equipped with a 63 Ni electron capture detector (ECD). The selenium level was 0.210 ± 0.013 μg/g in soil, 0.017 μg/L ± 0.002 in drinking water, 0.034 ± 0.002 μg/g in rice, and 0.034 ± 0.012 μg/g in wheat flour. This index showed that the Zhoukoudian area of Beijing was a moderate or marginal level selenium ecological landscape. The mean serum selenium level of the population was 75.01 ± 28.35 μg/L, ranging between 35.2 and 160.4 μg/L. A total of 279 (69.6%) individuals exhibited serum selenium level below 80 μg/L, which is the lowest threshold for the activity of glutathione peroxidases (GPx) in vivo. A total of 35 (8.5%) individuals exhibited serum selenium level below 45 μg/L. It is widely recommended that below this value (45 μg/L) there is an increased risk of cardiovascular disease and cancer. Multiple linear regression analysis showed that serum selenium level was positively associated with body mass index (β = 0.137; P = 0.011), serum total cholesterol TC (β = 0.785; P = 0.000), however, negatively associated with systolic blood pressure (β = - 0.172; P = 0.023), serum triglyceride (β = - 0.170; P = 0.007), high density lipoprotein-cholesterol (β = - 0.121; P = 0.027), and low high density lipoprotein-cholesterol (β = - 0.568; P = 0.027)

Effect of dietary supplementation with selenium-enriched yeast or sodium selenite on ruminal enzyme activities and blood chemistry in sheep

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Zita Faixová

2016-01-01

Full Text Available The experiment was conducted to evaluate the effect of feeding a diet supplemented with different forms of selenium on the rumen fluid, blood and serum enzyme activity and osmotic fragility of red blood cells in sheep. The experiment was carried out on 18 sheep of the Valashka breed at the age of 18 months, divided into 3 groups. The first group was given basal diet (BD with a Se content of 0.17 mg/kg of dry matter (DM. The second group received BD supplemented with 0.4 mg Se/kg of (DM in the form of sodium selenite. The third group received BD supplemented with 0.4 mg Se/kg of (DM in the form of Se-yeast extract. Duration of the trial was 12 weeks. Selenium concentration in blood and total rumen fluid were elevated in both supplemented groups with the highest values in Se-yeast-treated sheep. Blood glutathione peroxidase (GPx activity was significantly increased, regardless of the source of selenium. Osmotic resistance of red blood cells was not affected by selenium supplementation. The results indicate that feeding a diet supplemented with selenium from Se-yeast or selenite improved selenium status in blood and total rumen fluid. Selenium from sodium selenite was as effective as selenium from Se-yeast in the availability of selenium for the blood GPx activity. The effect of selenium supplementation on the ruminal enzyme activity depends on the selenium form; GGT and GDH were significantly higher in the Se-yeast supplement group, AST and ALP were significantly higher in the selenite supplement group.

Hyperoxia, unlike phorbol ester, induces glutathione peroxidase through a protein kinase C-independent mechanism.

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Jornot, L; Junod, A F

1997-01-01

Human selenium-dependent glutathione peroxidase (GP) is implicated as a mechanism of resistance against oxygen free radicals. The 5' flanking sequence upstream from the coding region of GP contained an oxygen-responsive element termed ORE1 that is responsive to hypoxia, as well as several copies of the activator protein-1 (AP-1)- and AP-1-like-binding sites. In this study, we sought to define the molecular events that lead to GP gene transcription in response to hyperoxia in human umbilical-vein endothelial cells, and asked whether such induction is mimicked and sustained by activation of protein kinase C (PKC) by phorbol esters. Treatment of cells with 100 nM phorbol 12,13-dibutyrate (PdBu) induced a delayed (24-48 h) but significant (2-fold) increase in steady-state GP mRNA levels. Steady-state GP mRNA levels also rose after exposure to 95% O2, again after considerable delay (48-72 h). For both PdBu and oxygen, induction was transcriptionally regulated, as demonstrated by nuclear run-on experiments. The simulations by PdBu and oxygen were additive. In contrast with PdBu, hyperoxia did not stimulate translocation of PKC from the cytosol to the particulate fraction, although the specific activity of both cytosolic and particulate-associated PKC was increased 2-fold in cells exposed to 95% O2 for 5 days. In addition, gel mobility-shift assays using double-stranded tumour-promoting-agent-responsive element (TRE) and nuclear extracts derived from phorbol- and oxygen-treated cells revealed that PdBu, but not hyperoxia, increased AP-1 DNA-binding activity. On the other hand, the up-regulation of GP expression by oxygen could not be accounted for by the ORE1 core sequence, since no specific protein-DNA binding activity could be detected using nuclear extracts from hyperoxic cells and ORE1. Taken together, these results suggest that there may be different molecular mechanisms controlling GP expression. After exposure to PdBu, GP undergoes transcriptional activation via a

Role of garlic oil and selenium as stimulators to some antioxidant defense system in irradiated male rats

International Nuclear Information System (INIS)

El-Gawish, M.A.; Abdel-Azeem, M.G.

2002-01-01

The increased level of lipid peroxide product; malondialdehyde (MDA) in various tissues of irradiated animals, may play a crucial role in damaging effects of exposure to ionizing radiation mediated by reactive free radicals generation. The protective efficiency of oral administration of garlic oil (500 mg/kg b.wt) three times weekly together with a single intraperitoneal injection of selenium (0.5 mg/kg b.wt) weekly for two weeks was examined on some antioxidant defense system as well as ultrastructural study in rats subjected to fractionated doses of gamma radiation up to a dose level of 6 Gy (1.5 Gy day after day). Exposure to gamma radiation induced a significant elevation in the level of malondialdehyde in plasma and liver and non-significant change was observed in superoxide dismutase activity (SOD). Also a significant increase was occurred in hepatic glutathione (GSH) content and glutathione peroxidase (GSHPx) activity. The pretreatment of irradiated rats with garlic oil and selenium caused a significant decrease in elevated level of MDA and a significant increase in the activity of SOD, GSHPx and GSH contents in both blood and liver. Concerning the ultrastructure studies, liver of irradiated rats showed abnormal shape of nucleus and nucleus membrane, swollen mitochondria with ruptured cristae, rupture of endoplasmic reticulum and vaculated cytoplasm, while intestine of irradiated rats exhibited deformed, shortened and abnormal structure of microvilli, accumulation of nuclear chromatin and dilatation of terminal web layer. In group of rats treated with garlic oil and selenium before exposure to gamma radiation, noticeable amelioration in ultrastructure changes of liver and intestine induced by irradiation was observed indicating a beneficial radioprotective role of both garlic oil and selenium

Selenium status and over-expression of interleukin-15 in celiac disease and autoimmune thyroid diseases

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Anna Velia Stazi

2010-12-01

Full Text Available In celiac disease (CD, for its multifactorial nature, the target organs are not limited to the gut, but include thyroid, liver, skin and reproductive and nervous systems. Between the extraintestinal symptoms associated with CD, autoimmune thyroid diseases (AITDs are more evident, underlining as CD-related autoimmune alterations can be modulated not only by gluten but also by various concurrent endogenous (genetic affinity, over-expression of cytokines and exogenous (environment, nutritional deficiency factors. In their pathogenesis a central role for over-expression of interleukin-15 (IL-15 is shown, by inhibiting apoptosis, leading to the perpetuation of inflammation and tissue destruction. Thyroid is particularly sensitive to selenium deficiency because selenoproteins are significant in biosynthesis and activity of thyroid hormones; besides, some selenoproteins as glutathione peroxidase are involved in inhibiting apoptosis. Thus, selenium malabsorption in CD can be thought as a key factor directly leading to thyroid and intestinal damage. Considering the complexity of this interaction and on the basis of available evidence, the aim of this review is to assess as preventive and therapeutic target the role of IL-15 and selenium in the pathogeneses of both CD and AITD.

Evaluation of iron and selenium losses in metalloproteins separated by gel electrophoresis by ICPMS

International Nuclear Information System (INIS)

Gherghel, I.; Fernandez, M.L.; Fernandez, B.; Pereiro, R.; Sanz-Medel, A.

2009-01-01

Full text: Metallomics addresses the study of metabolism, transport, and metal-protein interactions aiming to obtain relevant information of physiological and pathological alterations in living organisms. Gel electrophoresis is widely employed in proteomics and its use is actually extending to metallomics. Unfortunately, analysis of proteins by molecular techniques does not offer quantitative information. So, a good alternative could be their determination via the quantification of (semi)metal bound to the protein by ICPMS. In this work, we will show a detailed study of possible losses of protein and/or metal in Fe-bound and selenium proteins (transferrin and glutathione peroxidase, respectively) to evaluate the behaviour of the protein-metal interactions during the electrophoresis process. (author)

Influence of selenium supplementation on patients with inflammation: A pilot double blind randomized study.

Science.gov (United States)

Freitas, Renata Germano Borges de Oliveira Nascimento; Nogueira, Roberto José Negrão; Cozzolino, Silvia Maria Franciscato; Vasques, Ana Carolina Junqueira; Hessel, Gabriel

2017-09-01

The aim of the study was to analyze the effect of selenium supplementation on patients with inflammation receiving PN. This double-blind randomized study included 20 hospitalized patients experiencing an inflammatory process while being fed by PN, who were monitored in three stages: first 72 h (0), day 7 (1), and day 14 (2) of PN. The supplemented patients group (G+S) received 60 μg/d (0.75 μmol) of selenium as selenious acid which was added to the PN bag. The nonsupplemented group (G-S) did not receive selenium. The concentration range of 84 to 100 μg/L (1.07-1.27 μmol/L) was used as a reference of plasma selenium. The study included 20 patients (8 G+S and 12 G-S) mainly diagnosed with cancer and/or sepsis. Most of them were hospitalized in the intensive care unit and were receiving PN for clinical reasons. Plasma selenium was greater in the G+S than in the G-S (P = 0.05) in two stages (0 and 1). Since the start of assessment, C-reactive protein (CRP) levels were elevated; however, there was no statistical difference in CRP values between groups (P > 0.05). There was no significant change of glutathione peroxidase over time or between groups (P > 0.05). The selenium concentration was greater in the G+S than in the G-S, acting independently from CRP behavior. However, supplementation was not enough to reach the reference values. Copyright © 2017 Elsevier Inc. All rights reserved.

Rubidium contents in erythrocyte of children, rice and soil in the areas with different selenium status

International Nuclear Information System (INIS)

Liu Nianqing; Zhao Shunying; Qian Qinfang; Zhu Lianzhen; Piao Jianhua

1997-01-01

Rubidium concentration of erythrocyte of healthy children aged from 6-11 years living in four areas of Sichuan Province with different selenium status was measured by PIXE and the results show that the Rb concentration in erythrocyte for the Keshan Disease area is two times more than other three areas. Meanwhile the glutathione peroxidase (GSHPx) activity of erythrocyte was determined and the results confirm that children in the Keshan Disease area are really with selenium deficiency. The Rb contents in rice and soil samples from the Keshan Disease area and the Se-deficiency area but with Se-supplementation to the inhabitants, were tested by INNA. It was found that Rb contents in rice and soil from the former area were much higher than those from the latter. This result indicates that Rb in erythrocyte of children is mainly taken from staple food (rice) and that a higher Rb level in soil is probably another environmental factor causing the Keshan Disease

Changes of reduced glutathion, glutathion reductase, and glutathione peroxidase after radiation in guinea pigs

International Nuclear Information System (INIS)

Erden, M.; Bor, N.M.

1984-01-01

In this series of experiments the protective action of reduced glutathion due to ionizing radiation has been studied. In the experimental group 18 guinea pigs were exposed to successive radiations of 150 rad 3 or 4 days apart. Total dose given amounted to 750 rad which is the LD50 for guinea pigs. Blood samples were taken 30 min after each exposure. The control series were sham radiated but otherwise treated identically. The cells of the removed blood samples were separated by centrifugation and were subjected to the reduced glutathion stability test. GSSGR, GPer, and LDH enzyme activities were also measured of which the latter served as a marked enzyme. It was found that LDH did not show any alteration after radiation. The reduced glutathion stability test showed a consistent but minor reduction (P greater than 0.05), in the experimental group. GSSGR enzyme activity on the other hand was reduced significantly (from 176.48 +/- 11.32 to 41.34 +/- 1.17 IU/ml of packed erythrocytes, P less than 0.001) in the same group. GPer activity showed a consistent but minor elevation during the early phase of the experimental group. It was later increased significantly beginning after 600 rad total radiation on the fourth session (P less than 0.050)

Does a role for selenium in DNA damage repair explain apparent controversies in its use in chemoprevention?

Science.gov (United States)

Diamond, Alan M.

2013-01-01

The trace element selenium is an essential micronutrient that has received considerable attention for its potential use in the prevention of cancer. In spite of this interest, the mechanism(s) by which selenium might function as a chemopreventive remain to be determined. Considerable experimental evidence indicates that one possible mechanism by which selenium supplementation may exert its benefits is by enhancing the DNA damage repair response, and this includes data obtained using cultured cells, animal models as well as in human clinical studies. In these studies, selenium supplementation has been shown to be beneficial in reducing the frequency of DNA adducts and chromosome breaks, consequentially reducing the likelihood of detrimental mutations that ultimately contribute to carcinogenesis. The benefits of selenium can be envisioned as being due, at least in part, to it being a critical constituent of selenoproteins such as glutathione peroxidases and thioredoxin reductases, proteins that play important roles in antioxidant defence and maintaining the cellular reducing environment. Selenium, therefore, may be protective by preventing DNA damage from occurring as well as by increasing the activity of repair enzymes such as DNA glycosylases and DNA damage repair pathways that involve p53, BRCA1 and Gadd45. An improved understanding of the mechanism of selenium’s impact on DNA repair processes may help to resolve the apparently contradicting data obtained from decades of animal work, human epidemiology and more recently, clinical supplementation studies. PMID:23204505

Selenoprotein P: an extracellular protein with unique physical characteristics and a role in selenium homeostasis.

Science.gov (United States)

Burk, Raymond F; Hill, Kristina E

2005-01-01

Selenoprotein P is an abundant extracellular glycoprotein that is rich in selenocysteine. It has two domains with respect to selenium content. The N-terminal domain of the rat protein contains one selenocysteine residue in a UxxC redox motif. This domain also has a pH-sensitive heparin-binding site and two histidine-rich amino acid stretches. The smaller C-terminal domain contains nine selenocysteine and ten cysteine residues. Four isoforms of selenoprotein P are present in rat plasma. They share the same N terminus and amino acid sequence. One isoform is full length and the three others terminate at the positions of the second, third, and seventh selenocysteine residues. Selenoprotein P turns over rapidly in rat plasma with the consequence that approximately 25% of the amount of whole-body selenium passes through it each day. Evidence supports functions of the protein in selenium homeostasis and oxidant defense. Selenoprotein P knockout mice have very low selenium concentrations in the brain, the testis, and the fetus, with severe pathophysiological consequences in each tissue. In addition, those mice waste moderate amounts of selenium in the urine. Selenoprotein P binds to endothelial cells in the rat, and plasma levels of the protein correlate with prevention of diquat-induced lipid peroxidation and hepatic endothelial cell injury. The mechanisms of these apparent functions remain speculative and much work on the mechanism of selenoprotein P function lies ahead. Measurement of selenoprotein P in human plasma has shown that it is depressed by selenium deficiency and by cirrhosis. Selenium supplementation of selenium-deficient human subjects showed that glutathione peroxidase activity was optimized before selenoprotein P concentration was optimized, indicating that plasma selenoprotein P is the better index of human selenium nutritional status.

Glutathione level and its relation to radiation therapy in patients with cancer of uterine cervix

International Nuclear Information System (INIS)

Mukundan, H.; Bahadur, A.K.; Kumar, A.; Sardana, S.; Naik, S.L.D.; Ray, A.; Sharma, B.K.

1999-01-01

Glutathione functions as an important antioxidant in the destruction of hydrogen peroxide and lipid peroxides by providing substrate for the glutathione peroxidase and also promotes the ascorbic acid. Glutathione plays a vital role in detoxification of xenobiotics, carcinogens, free radicals and maintenance of immune functions. The study was aimed to determine plasma glutathione as well as erythrocyte glutathione and glutathione peroxidase in patients with invasive cervical carcinoma (n=30) before initiation and after completion of radiotherapy and subsequently, at the time of first three monthly follow-up visit. The levels of plasma glutathione, erythrocyte glutathione and glutathione peroxidase activity were found to be lower in all cervical cancer patients as compared to age matched normal control women. The study indicates a change in antioxidant status in relation with the glutathione system among patients with invasive carcinoma of the uterine cervix. This study also demonstrates the effect of radiation therapy on this antioxidant system. (author)

Plasma Selenium Biomarkers in Low Income Black and White Americans from the Southeastern United States

Science.gov (United States)

Hargreaves, Margaret K.; Liu, Jianguo; Buchowski, Maciej S.; Patel, Kushal A.; Larson, Celia O.; Schlundt, David G.; Kenerson, Donna M.; Hill, Kristina E.; Burk, Raymond F.; Blot, William J.

2014-01-01

Biomarkers of selenium are necessary for assessing selenium status in humans, since soil variation hinders estimation of selenium intake from foods. In this study, we measured the concentration of plasma selenium, selenoprotein P (SEPP1), and glutathione peroxidase (GPX3) activity and their interindividual differences in 383 low-income blacks and whites selected from a stratified random sample of adults aged 40–79 years, who were participating in a long-term cohort study in the southeastern United States (US). We assessed the utility of these biomarkers to determine differences in selenium status and their association with demographic, socio-economic, dietary, and other indicators. Dietary selenium intake was assessed using a validated food frequency questionnaire designed for the cohort, matched with region-specific food selenium content, and compared with the US Recommended Dietary Allowances (RDA) set at 55 µg/day. We found that SEPP1, a sensitive biomarker of selenium nutritional status, was significantly lower among blacks than whites (mean 4.4±1.1 vs. 4.7±1.0 mg/L, p = 0.006), with blacks less than half as likely to have highest vs. lowest quartile SEPP1 concentration (Odds Ratio (OR) 0.4, 95% Confidence Interval (CI) 0.2–0.8). The trend in a similar direction was observed for plasma selenium among blacks and whites, (mean 115±15.1 vs. 118±17.7 µg/L, p = 0.08), while GPX3 activity did not differ between blacks and whites (136±33.3 vs. 132±33.5 U/L, p = 0.320). Levels of the three biomarkers were not correlated with estimated dietary selenium intake, except for SEPP1 among 10% of participants with the lowest selenium intake (≤57 µg/day). The findings suggest that SEPP1 may be an effective biomarker of selenium status and disease risk in adults and that low selenium status may disproportionately affect black and white cohort participants. PMID:24465457

Differences in associations between markers of antioxidative defense and asthma are sex specific

DEFF Research Database (Denmark)

Malling, Tine Halsen; Sigsgaard, Torben; Andersen, Helle R

2010-01-01

on a screening questionnaire, random sampling, or both. Serum selenium concentrations and antioxidant enzyme activities (superoxide dismutase, glutathione peroxidase [GPX], glutathione reductase [GR], and glucose-6-phosphate dehydrogenase [G6PD]) in erythrocytes were measured. Asthma was defined as either...

Assessment of selenium bioavailability from naturally produced high-selenium soy foods in selenium-deficient rats.

Science.gov (United States)

Yan, Lin; Reeves, Philip G; Johnson, LuAnn K

2010-10-01

We assessed the bioavailability of selenium (Se) from a protein isolate and tofu (bean curd) prepared from naturally produced high-Se soybeans. The Se concentrations of the soybeans, the protein isolate and tofu were 5.2±0.2, 11.4±0.1 and 7.4±0.1mg/kg, respectively. Male weanling Sprague-Dawley rats were depleted of Se by feeding them a 30% Torula yeast-based diet (4.1μg Se/kg) for 56 days, and then they were replenished with Se for an additional 50 days by feeding them the same diet containing 14, 24 or 30 μg Se/kg from the protein isolate or 13, 23 or 31 μg Se/kg from tofu, respectively. l-Selenomethionine (SeMet) was used as a reference. Selenium bioavailability was determined on the basis of the restoration of Se-dependent enzyme activities and tissue Se concentrations in Se-depleted rats, comparing those responses for the protein isolate and tofu to those for SeMet by using a slope-ratio method. Dietary supplementation with the protein isolate or tofu resulted in linear or log-linear, dose-dependent increases in glutathione peroxidase activities in blood and liver and in thioredoxin reductase activity in liver. Furthermore, supplementation with the protein isolate or tofu resulted in linear or log-linear, dose-dependent increases in the Se concentrations of plasma, liver, muscle and kidneys. These results indicated an overall bioavailability of approximately 101% for Se from the protein isolate and 94% from tofu, relative to SeMet. We conclude that Se from naturally produced high-Se soybeans is highly bioavailable in this model and that high-Se soybeans may be a good dietary source of Se. Published by Elsevier GmbH.

Selenium Digestibility and Bioactivity in Dogs: What the Can Can, the Kibble Can't.

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Mariëlle van Zelst

Full Text Available There is a growing concern for the long-term health effects of selenium (Se over- or underfeeding. The efficiency of utilization of dietary Se is subject to many factors. Our study in dogs evaluated the effect of diet type (canned versus kibble and dietary protein concentration on Se digestibility and bioactivity. Canned and kibble diets are commonly used formats of dog food, widely ranging in protein concentration. Twenty-four Labrador retrievers were used and four canned and four kibble diets were selected with crude protein concentrations ranging from 10.1 to 27.5 g/MJ. Crude protein concentration had no influence on the digestibility of Se in either canned or kibble diets, but a lower Se digestibility was observed in canned compared to kibble diets. However, the biological activity of Se, as measured by whole blood glutathione peroxidase, was higher in dogs fed the canned diets than in dogs fed the kibble diets and decreased with increasing crude protein intake. These results indicate that selenium recommendations in dog foods need to take diet type into account.

Selenium Digestibility and Bioactivity in Dogs: What the Can Can, the Kibble Can't.

Science.gov (United States)

van Zelst, Mariëlle; Hesta, Myriam; Gray, Kerry; Beech, Karen; Cools, An; Alexander, Lucille G; Du Laing, Gijs; Janssens, Geert P J

2016-01-01

There is a growing concern for the long-term health effects of selenium (Se) over- or underfeeding. The efficiency of utilization of dietary Se is subject to many factors. Our study in dogs evaluated the effect of diet type (canned versus kibble) and dietary protein concentration on Se digestibility and bioactivity. Canned and kibble diets are commonly used formats of dog food, widely ranging in protein concentration. Twenty-four Labrador retrievers were used and four canned and four kibble diets were selected with crude protein concentrations ranging from 10.1 to 27.5 g/MJ. Crude protein concentration had no influence on the digestibility of Se in either canned or kibble diets, but a lower Se digestibility was observed in canned compared to kibble diets. However, the biological activity of Se, as measured by whole blood glutathione peroxidase, was higher in dogs fed the canned diets than in dogs fed the kibble diets and decreased with increasing crude protein intake. These results indicate that selenium recommendations in dog foods need to take diet type into account.

Selenium Digestibility and Bioactivity in Dogs: What the Can Can, the Kibble Can’t

Science.gov (United States)

van Zelst, Mariëlle; Hesta, Myriam; Gray, Kerry; Beech, Karen; Cools, An; Alexander, Lucille G.; Du Laing, Gijs; Janssens, Geert P. J.

2016-01-01

There is a growing concern for the long-term health effects of selenium (Se) over- or underfeeding. The efficiency of utilization of dietary Se is subject to many factors. Our study in dogs evaluated the effect of diet type (canned versus kibble) and dietary protein concentration on Se digestibility and bioactivity. Canned and kibble diets are commonly used formats of dog food, widely ranging in protein concentration. Twenty-four Labrador retrievers were used and four canned and four kibble diets were selected with crude protein concentrations ranging from 10.1 to 27.5 g/MJ. Crude protein concentration had no influence on the digestibility of Se in either canned or kibble diets, but a lower Se digestibility was observed in canned compared to kibble diets. However, the biological activity of Se, as measured by whole blood glutathione peroxidase, was higher in dogs fed the canned diets than in dogs fed the kibble diets and decreased with increasing crude protein intake. These results indicate that selenium recommendations in dog foods need to take diet type into account. PMID:27043433

Effect of Pistacia Atlantica Extract on Glutathione Peroxidase Tissue Levels and Total Oxidative Capacity of Liver and Plasma Lipid Profile of Rats

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Parvin Farzanegi

2013-11-01

Full Text Available Background: Exercise causes increased oxygen consumption, leaving cells exposed to oxidative stress. Antioxidants may have a protective effect by inhibiting lipid peroxidation. Thus, this study aims to examine the effect of Pistacia atlantica extract on glutathione peroxidase levels and total oxidative capacity of liver and plasma lipid profile of rats. Materials and Methods: In this experimental study, 28 female rats’ weight 155.8±2.7 grams were randomly and equally divided into 4 groups of exercise-saline, control-saline, exercise-mastic, and control-mastic. The exercise groups exercised for 8 weeks (5 days per week, 60 minutes daily, 25 meters per minute, on a zero degree slope. The rats received equal volumes of mastic and saline orally for 4 weeks. Blood and tissue samples were taken 72 hours after the last exercise session. Data were analyzed using one-way variance analysis (ANOVA.Results: Consumption of Pistacia atlantica extract together with endurance exercising for 8 weeks did not significantly affect glutathione peroxidase concentration, total oxidative capacity, LDL, triglyceride, or cholesterol, but significantly reduced HDL (p=0.002.Conclusion: Results showed that antioxidant and lipid profile levels were not affected by consumption of supplements and endurance exercising. However, further studies are required to assess the long term effects of this herbal extract.

Cigarette smoke exposure alters [14C]arachidonic acid metabolism in aortas and platelets of rats fed various levels of selenium and vitamin E

International Nuclear Information System (INIS)

Valentovic, M.A.; Gairola, C.; Lubawy, W.C.

1985-01-01

Rats were placed on a basal diet supplemented with 0, 0.03, or 3 ppm selenium and 0 or 20 ppm vitamin E for 41-43 wk. Selenium deficiency decreased hepatic glutathione peroxidase activity and lowered both aortic prostacyclin (PGI2) and platelet thromboxane (TXA2) production compared to selenium- and vitamin E-supplemented animals. Vitamin E deficiency increased hepatic lipid peroxidation and decreased aortic PGI2 synthesis. Rats exposed daily for 31-32 wk to fresh smoke from a UK 2R1 reference cigarette had carboxyhemoglobin levels of 0.75 +/- 0.12 and 4.73 +/- 0.12% in sham- and smoke-exposed groups, respectively. Animals chronically exposed to cigarette smoke displayed a nearly twofold increase in pulmonary arylhydrocarbon hydroxylase activity. Smoke exposure produced a 26-33% decrease in aortic PGI2 synthesis compared to shams in the Se3E20, Se0.03E20, and Se3E0 groups. Smoking also increased platelet thromboxane 91% and 98% in the Se3E20 and Se3E0 groups compared to shams. It is concluded that cigarette-smoke exposure and selenium or vitamin E deficiency alter aortic PGI2 and platelet TXA2 production

The effects of selenium, zinc and vitamin E supplementation on performance of Broiler Breeder Males

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L. Zezza

2011-03-01

Full Text Available Evidence from the literature and practical experiences suggests that nutritional factors are perhaps the most crucial for their direct effects on the reproductive phenomenon. Several studies and reviews (Barnes et al., 1996; Brake and Garlich, 1989; Chen et al., 1994; Donoghue et al., 1995; Donoghue et al., 1997; Froman et al., 1997; Hocking and Bernard, 1997; Holm, 1998 describe the effects of quantitative feed and energy on reproductive performance of farm animals but only recently there was an increasing attention for the effects of micronutrients intake. The aim of the present work was to verify and compare the effects of a supplementation of selenium, zinc and vitamin E on quality of poultry semen, with a particular attention to the selenium, because its beneficial effects on reproduction (Surai, 2002 needs further elucidation. These micronutrients were chosen because play a fundamental role in semen quality, in fact it was known that chicken semen contains the natural antioxidant vitamin E (Surai, 1997; Surai, 2000 together with antioxidant enzymes glutathione peroxidase (GSH-Px and superoxide dismutase (SOD...

Actividad de glutatión peroxidasa en bovinos lecheros a pastoreo correlacionada con la concentración sanguinea y plasmática de selenio Blood activity of glutathione peroxidase and its correlation with blood selenium concentration in grazing dairy cattle

Directory of Open Access Journals (Sweden)

Alejandro Ceballos

1999-12-01

Full Text Available Con el objeto de validar una técnica para determinar la actividad sanguínea de glutatión peroxidasa (GSH-Px; EC 1.11.1.9 en el Laboratorio de Patología Clínica de la Universidad Austral de Chile y establecer la correlación entre su actividad y la concentración sanguínea y plasmática de selenio (Se en bovinos a pastoreo en rebaños lecheros del sur de Chile, se tomaron 5-10 mL de sangre heparinizada a 112 vacas de ocho rebaños en la provincia de Valdivia. La actividad enzimática se analizó mediante una técnica cinética, y el Se por activación de neutrones. Fueron calculadas la inexactitud e imprecisión de la técnica cinética y se describen el rango, promedio y desviación estándar de la actividad enzimática. La correlación entre la actividad sanguínea de GSH-Px y la concentración de Se fue obtenida mediante el coeficiente de correlación simple. La inexactitud e imprecisión fueron 5,9% y 10%, respectivamente. La actividad de GSH-Px fue 89 ± 45 U/g de hemoglobina (Hb y la correlación entre las variables señaladas fue r=0,97 (PSelenium (Se is part of the antioxidant enzyme glutathione peroxidase (GSH-Px; EC 1.11.1.9 structure, whose blood activity is related to the blood level of selenium. This study was designed to validate the analytical method to analyze the GSH-Px blood activity at the Clinical Pathology Laboratory of the Universidad Austral de Chile, and to correlate it with blood Se level in dairy cattle from the South of Chile. Blood heparinized samples were taken from 112 dairy cows from eight dairy herds located at Valdivia province, Chile. A kinetic NADPH-dependent technique was used to analyze the blood GSH-Px, and the content of Se in blood and plasma was analyzed by neutron activation. The Se concentration in blood was analyzed in 12 samples to correlate GSH-Px blood activity with blood and plasma Se level. The inaccuracy and imprecision were 5.9% and 10%, respectively. The mean and standard deviation of the

Effects of reduced glutathion and vitamin c on cisplatin-induced ...

African Journals Online (AJOL)

glutathione peroxidase [GSHPx], catalase [CAT], glutathione reductase [GSHR] activities and gene expression, glutathione [GSH] content) and lipid peroxidation products (malondialdehyde, MDA) in rat liver tissue were measured. CDDP hepatotoxicity was manifested by an increase in serum ALT and AST, elevation of MDA ...

Comparative effect of selenium and selenium tolerant microbes on brachiaria reptans l. growth

International Nuclear Information System (INIS)

Yasin, M.; Faisal, M.

2014-01-01

Brachiaria reptans L. is an annual grass. It is good fodder grass which is distributed in tropical Asia, Kenya, Pakistan and India and introduced throughout the tropics. In present study we determine the growth correlation among B. reptans, selenium (Se) and two Se tolerant bacteria (Bacillus licheniformis-YAP7 and Bacillus cereus-YAP6). Plants treated with Se showed a significant decrease in shoot length (33%) and fresh biomass (41%) compared to control. When plants were co-cultivated in the presence of bacteria or Se and bacteria both the shoot length increased (16-34%) significantly compared to control. B. reptans plants treated with Se have shown a significant decrease in peroxidase contents (59%) compared to control. However, bacterial inoculation of Se treated plants resulted in significant increase in peroxidase contents (113-171%). Selenium treatment caused increase in leaf soluble protein contents compared to control. In conclusion, bacteria can enhance B. reptans growth under Se stress. (author)

Rethinking mercury: the role of selenium in the pathophysiology of mercury toxicity.

Science.gov (United States)

Spiller, Henry A

2018-05-01

There is increasing evidence that the pathophysiological target of mercury is in fact selenium, rather than the covalent binding of mercury to sulfur in the body's ubiquitous sulfhydryl groups. The role of selenium in mercury poisoning is multifaceted, bidirectional, and central to understanding the target organ toxicity of mercury. An initial search was performed using Medline/PubMed, Toxline, Google Scholar, and Google for published work on mercury and selenium. These searches yielded 2018 citations. Publications that did not evaluate selenium status or evaluated environmental status (e.g., lake or ocean sediment) were excluded, leaving approximately 500 citations. This initial selection was scrutinized carefully and 117 of the most relevant and representative references were selected for use in this review. Binding of mercury to thiol/sulfhydryl groups: Mercury has a lower affinity for thiol groups and higher affinity for selenium containing groups by several orders of magnitude, allowing for binding in a multifaceted way. The established binding of mercury to thiol moieties appears to primarily involve the transport across membranes, tissue distribution, and enhanced excretion, but does not explain the oxidative stress, calcium dyshomeostasis, or specific organ injury seen with mercury. Effects of mercury on selenium and the role this plays in the pathophysiology of mercury toxicity: Mercury impairs control of intracellular redox homeostasis with subsequent increased intracellular oxidative stress. Recent work has provided convincing evidence that the primary cellular targets are the selenoproteins of the thioredoxin system (thioredoxin reductase 1 and thioredoxin reductase 2) and the glutathione-glutaredoxin system (glutathione peroxidase). Mercury binds to the selenium site on these proteins and permanently inhibits their function, disrupting the intracellular redox environment. A number of other important possible target selenoproteins have been identified

Protective effect of selenium against aluminium chloride induced cardiotoxicity in rats

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Imen Ghorbel

2017-08-01

Full Text Available Our study pertains to evaluate the protective effect of selenium (Se, used as a nutritional supplement, against aluminium chloride induced cardiotoxicity in rats. Rats have received during 21 days either AlCl3 (400 ppm via drinking water, AlCl3 associated with Na2SeO3 (0.5 mg/kg of diet or only Na2SeO3. Co-administration of Se to AlCl3 treated rats alleviated heart oxidative stress objectified by a decrease of malondialdehyde, hydrogen peroxide and protein carbonyls levels. An improvement in antioxidant redox status, enzymatic (catalase, superoxide dismutase and glutathione peroxidase and non enzymatic (reduced glutathione, non protein thiols and vitamin C was also observed in Se treated rats.  LDH and CK activities, TC, LDL-C levels, TC/HDL-C and LDL-C/HDL-C ratios were increased, while HDL-C and TG decreased in rats treated with AlCl3. Cardiac biomarkers and lipid profile were restored to near control values by the supplementation of Se. Our results revealed that Se, a trace element with antioxidant properties, was effective in preventing heart damage induced by aluminium chloride.

Selenium Status in Heifers, Late Pregnancy Cows and Their Calves in the Šumava Region, Czech Republic

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P. Slavík

2007-01-01

Full Text Available The objective of this study was to ascertain selenium status in beef cattle in different stages of production in the Šumava region. In the region, blood collections and analyses for selected metabolic variables were performed in 54 animals in different production stages (18 heifers, 18 cows in late pregnancy and 18 calves aged 3 weeks on the average. Three herds were studied. The selenium status was determined both directly by measuring serum selenium (Se contents and indirectly by measuring glutathione peroxidase (GSH-Px activity in whole blood. The mean serum selenium concentration in all the animals under study (n = 54 was 30.6 μg/l +/- 2.91, and mean GSH-Px activity was 167.01 μkat/l +/- 92.39. In heifers, mean serum selenium concentration was 34.81 μg/l +/- 13.84; mean GSHPx activity was 186.96 μkat/l +/- 112.15. In late pregnancy cows, mean serum selenium concentration was 26.58 μg/l +/- 8.01, mean GSH-Px activity was 94.55 +/- 35.72 μkat/l. In calves, mean serum selenium concentration and GSH-Px activity were 30.41 μg/l +/- 12 and 219.54 μkat/l +/- 64.41, respectively. There was a statistically significant difference between the heifers and late pregnancy cows in both variables under study. However, between the late pregnancy cows and the calves, only the difference in GSH-Px activity was significant. The results indicate severe Se deficiency in the animals under study. It means apart from other things that mineral licks used did not provide enough minerals to meet the basic requirements of the animals.

In vivo and in vitro assessment of the role of glutathione antioxidant system in anthracycline-induced cardiotoxicity

Czech Academy of Sciences Publication Activity Database

Vávrová, A.; Popelová, O.; Štěrba, M.; Jirkovský, E.; Hašková, P.; Mertlíková-Kaiserová, Helena; Geršl, V.; Šimůnek, T.

2011-01-01

Roč. 85, č. 5 (2011), s. 525-535 ISSN 0340-5761 Grant - others:GA ČR(CZ) GA305/09/0416 Program:GA Institutional research plan: CEZ:AV0Z40550506 Keywords : anthracycline cardiotoxicity * daunorubicin * glutathione * glutathione peroxidase * glutathione peroxidase Subject RIV: CE - Biochemistry Impact factor: 4.674, year: 2011

A systematic review and meta-analysis of the circulatory, erythrocellular and CSF selenium levels in Alzheimer's disease: A metal meta-analysis (AMMA study-I).

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Reddy, Varikasuvu Seshadri; Bukke, Suman; Dutt, Naveen; Rana, Puneet; Pandey, Arun Kumar

2017-07-01

Available studies in the literature on the selenium levels in Alzheimer's disease (AD) are inconsistent with some studies reporting its decrease in the circulation, while others reported an increase or no change as compared to controls. The objective of this study was to perform a meta-analysis of circulatory (plasma/serum and blood), erythrocyte and cerebrospinal fluid (CSF) selenium levels in AD compared controls. We also performed a meta-analysis of the correlation coefficients (r) to demonstrate the associations between selenium and glutathione peroxidase (GPx) in AD patients. All major databases were searched for eligible studies. We included 12 case-control/observational studies reporting selenium concentrations in AD and controls. Pooled-overall effect size as standardized mean difference (SMD) and pooled r-values were generated using Review Manager 5.3 and MedCalc 15.8 software. Random-effects meta-analysis indicated a decrease in circulatory (SMD=-0.44), erythrocellular (SMD=-0.52) and CSF (SMD=-0.14) selenium levels in AD patients compared to controls. Stratified meta-analysis demonstrated that the selenium levels were decreased in both the subgroups with (SMD=-0.55) and without (SMD=-0.37) age matching between AD and controls. Our results also demonstrated a direct association between decreased selenium levels and GPx in AD. This meta-analysis suggests that circulatory selenium concentration is significantly lower in AD patients compared to controls and this decrease in selenium is directly correlated with an important antioxidant enzyme, the GPx, in AD. Copyright © 2017 Elsevier GmbH. All rights reserved.

Study of some antioxidant enzymes and selenium levels in children with chronic renal failure

International Nuclear Information System (INIS)

Moawad, A.T.

2006-01-01

Chronic renal failure (CRF) is a complex of clinical, chemical and metabolic disturbances that resulted from chronic reduction in renal function. Despite of many investigations on the pathogenesis of CRF, much remains unexplained. Studies of disorders of oxidative metabolism have indicated the role of reactive oxygen species (ROS) in the development of symptoms and complications of this disease. Therefore, selenium (Se) concentration, glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) were determined in 25 children (15 males and 10 females) with advanced CRF. They were diagnosed in the Pediatric Nephrology Unit, Children Hospital, Ain Shams University, Egypt. Their ages ranged from 6-17 years with mean of 11.4 ± 3.54 years. Fifteen healthy control subjects (8 males and 7 females) matched in age were served as controls. This study revealed a very high significant decrease in the levels of antioxidant enzymes; glutathione peroxidase and superoxide dismutase. The level of plasma Se concentration in patients was very highly significantly decreased as compared to the control group. Also, there were significant positive correlations between Se and total protein and albumin. Furthermore, there were negative correlations between Se, SOD, GSH-Px and both of blood urea and serum creatinine among uremic children. It could be concluded that plasma Se concentration and the activities of antioxidant enzymes (GSH-Px and SOD) in uremic children could be helpful in identifying the progress of kidney impairment and the response of the treatment

Variation in risk indicators of cardiovascular disease during the menstrual cycle: an investigation of within-subject variations in glutathione peroxidase, haemostatic variables, lipids and lipoproteins in healthy young women

DEFF Research Database (Denmark)

Larsen, L F; Andersen, H R; Hansen, A B

1996-01-01

Variations in erythrocyte glutathione peroxidase activity, serum concentrations of lipids and lipoproteins and in blood coagulation and fibrinolysis during the menstrual cycle were studied in healthy young women. Blood samples were drawn twice a week for 9 weeks. A group of males was used...

Toxicity and oxidative stress of different forms of organic selenium (Se) and dietary protein in mallard (Anas platyrhynchos) ducklings

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Hoffman, D.; Heinz, G.; Eisemann, J.; Pendleton, G.

1994-01-01

High concentrations of Se have been found in aquatic food chains associated with irrigation drainwater and toxicity to fish and wildlife. Earlier studies have compared toxicities of Se as selenite and as seleno-DL-methionine (DL) in mallards. This study compares DL, seleno-L-methionine (L), selenized yeast (Y) and selenized wheat (W). Day-old mallard ducklings received an untreated diet (controls) containing 75% wheat (22% protein) or the same diet containing 15 or 30 ppm Se in the above forms. After 2 weeks blood and liver samples were collected for biochemical assays and Se analysis. All forms of selenium caused significant increases in plasma and hepatic glutathione peroxidase activities. Se as L was the most toxic, resulting in high mortality (64%) and impaired growth (>50%) and the greatest increase in ratio of oxidized to reduced glutathione with 30 ppm in the diet. Se as Y accumulated the least in liver. In a subsequent experiment with 30% dietary protein Se as L was less toxic.

The effect of seedling chilling on glutathione content, catalase and peroxidase activity in Brassica oleracea L. var. italica

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Renata Wojciechowska

2013-09-01

Full Text Available The study was designed to determine the possible relationship between Brassica oleracea var. italica seedlings stored at 2°C in the dark for seven and fourteen days, respectively, and the level of certain antioxidant parameters in particular organs. A parallel objective of the experiment was to determine if the reaction of seedlings to low temperature might be persistent in fully developed plants until harvest time. After 14 days of chilling a significant increase in the glutathione content was observed in the seedling leaves in comparison to the non-chilled plants. During vegetation in field conditions this effect was maintained in leaves up to the stage of formation of flower buds. At harvest the highest content of glutathione was demonstrated in broccoli heads, obtained from plants, which were previously chilled in the seedling phase for two weeks. Peroxidase activity in broccoli seedlings increased each year of the three-year study due to the duration of the cooling time, whereas in the case of catalase the changes were not so distinct. At harvest time the activity of both enzymes in the leaves and flower buds fluctuated according to the particular year of study.

Selenium determination in biological materials by neutron activation analysis - statistical comparison between the use of 77m Se (t1/2 17.45 s) and 75 Se (t1/2 = 119,8 d)

International Nuclear Information System (INIS)

Catharino, Marilia G.M.; Vasconcelos, Marina B.A.

2002-01-01

Selenium is nowadays considered to be an essential trace element in human diet. The most extensively studied biochemical role of this element is related to its participation in the composition of glutathione peroxidase. This enzyme acts as an antioxidant for the free radicals formed in the human body. In the present work, selenium was determined by INAA in reference materials ('Human hair' IAEA-085, 'Human hair' IAEA-086, 'Dogfish Liver' DOLT-1 e 'Dogfish Muscle' DORM-1) and in toenails and vitamin supplement, using the short-lived radioisotope 77m Se. The usual method, which utilizes long- lived 75 Se, was also employed, in order to make a comparative study. A statistical test was applied for this comparison. It was verified that the average concentrations of selenium, in the reference materials and in the samples analyzed, do not differ statistically at a significance level of 0.05, which indicates the applicability of the short-lived 77m Se for INAA of the matrixes studied. (author)

Optimal serum selenium concentrations are associated with lower depressive symptoms and negative mood among young adults.

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Conner, Tamlin S; Richardson, Aimee C; Miller, Jody C

2015-01-01

There is evidence that low, and possibly high, selenium status is associated with depressed mood. More evidence is needed to determine whether this pattern occurs in young adults with a wide range of serum concentrations of selenium. The aim of this study was to determine if serum selenium concentration is associated with depressive symptoms and daily mood states in young adults. A total of 978 young adults (aged 17-25 y) completed the Center for Epidemiological Studies-Depression scale and reported their negative and positive mood daily for 13 d using an Internet diary. Serum selenium concentration was determined by inductively coupled plasma mass spectrometry. ANCOVA and regression models tested the linear and curvilinear associations between decile of serum selenium concentration and mood outcomes, controlling for age, gender, ethnicity, BMI, and weekly alcohol intake. Smoking and childhood socioeconomic status were further controlled in a subset of participants. The mean ± SD serum selenium concentration was 82 ± 18 μg/L and ranged from 49 to 450 μg/L. Participants with the lowest serum selenium concentration (62 ± 4 μg/L; decile 1) and, to a lesser extent, those with the highest serum selenium concentration (110 ± 38 μg/L; decile 10) had significantly greater adjusted depressive symptoms than did participants with midrange serum selenium concentrations (82 ± 1 to 85 ± 1 μg/L; deciles 6 and 7). Depressive symptomatology was lowest at a selenium concentration of ∼85 μg/L. Patterns for negative mood were similar but more U-shaped. Positive mood showed an inverse U-shaped association with selenium, but this pattern was less consistent than depressive symptoms or negative mood. In young adults, an optimal range of serum selenium between ∼82 and 85 μg/L was associated with reduced risk of depressive symptomatology. This range approximates the values at which glutathione peroxidase is maximal, suggesting that future research should investigate

Preparation and antioxidant properties of selenium nanoparticles-loaded chitosan microspheres

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Bai K

2017-06-01

Full Text Available Kaikai Bai,1,2 Bihong Hong,1,2 Jianlin He,1,2 Zhuan Hong,1,2 Ran Tan1,2 1Third Institute of Oceanography, 2Engineering Research Center of Marine Biological Resource, Comprehensive Utilization, State Oceanic Administration, Xiamen, People’s Republic of China Abstract: Selenium nanoparticles (SeNPs, as a special form of selenium (Se supplement, have attracted worldwide attention due to their favorable properties and unique bioactivities. Herein, an eco-friendly and economic way to prepare stable SeNPs is introduced. SeNPs were synthesized in aqueous chitosan (CTS and then embedded into CTS microspheres by spray-drying, forming selenium nanoparticles-loaded chitosan microspheres (SeNPs-M. The physicochemical properties including morphology, elemental state, size distribution and surface potential were investigated. Institute of Cancer Research mice were used as model animal to evaluate the bioactivities of SeNPs-M. Trigonal-phase SeNPs of ~35 nm were synthesized, and SeNPs-M physically embedding those SeNPs were successfully prepared. Amazingly, acute toxicity test indicated that SeNPs-M were much safer than selenite in terms of Se dose, with a LD50 of around 18-fold of that of selenite. In addition, SeNPs-M possessed powerful antioxidant activities, as evidenced by a dramatic increase of both Se retention and the levels of glutathione peroxidase, superoxide dismutase and catalase. The design of SeNPs-M can offer a new way for further development of SeNPs with a higher efficacy and better biosafety. Thus, SeNPs-M may be a potential candidate for further evaluation as an Se supplement with antioxidant properties and be used against Se deficiency in animals and human beings. Keywords: selenium, nano, microsphere, chitosan, antioxidant

Ethanol Consumption by Wistar Rat Dams Affects Selenium Bioavailability and Antioxidant Balance in Their Progeny

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Olimpia Carreras

2009-07-01

Full Text Available Ethanol consumption affects maternal nutrition, the mothers’ antioxidant balance and the future health of their progeny. Selenium (Se is a trace element cofactor of the enzyme glutathione peroxidase (GPx. We will study the effect of ethanol on Se bioavailability in dams and in their progeny. We have used three experimental groups of dams: control, chronic ethanol and pair-fed; and three groups of pups. Se levels were measured by graphite-furnace atomic absorption spectrometry. Serum and hepatic GPx activity was determined by spectrometry. We have concluded that ethanol decreased Se retention in dams, affecting their tissue Se deposits and those of their offspring, while also compromising their progeny’s weight and oxidation balance. These effects of ethanol are caused by a reduction in Se intake and a direct alcohol-generated oxidation action.

Effect of selenium on its content in milk and performance of dairy cows in ecological farming

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Pavel Horký

2015-08-01

Full Text Available Currently, the ecological farming is increasingly spread in the European Union. The aim of this relatively young farming method is a friendly approach to agricultural production with an emphasis to deliver healthy raw materials and food to final consumer. Selenium is included in an essential trace micronutrients which are necessary for the proper process of physiological reactions. It is a part of glutathione peroxidase, which is a powerful antioxidant. At present,  selenium-deficiency can occur in feed and food in central Europe. Selenium deficiency is one cause of the higher occurrence of cardiovascular diseases. The aim of the experiment was to study whether the addition of selenium to the diet of dairy cows in ecological farming can increase its concentration in milk and affect quantitative (milk yield and quality (content of protein, fat, lactose, somatic cells and urea milk indicators. The experiment included twenty cows of Holstein breed. The first experimental group of cows (n = 10 was fed with selenium in an amount of 0.3 mg.kg-1 (as selenomethionine in the feed dose. The control group (n = 10 was not fed with the increased selenium in the feed dose. The basic feed dose contained 0.17 mg of Se/kg in the diet. For dairy cows, daily intake was of 20.5 kg of dry matter feed. The duration of the experiment was set at 45 days. The selenium concentration in milk was measured from 0.13 to 0.15 µg.mL-1 in the experimental group of cows during the evaluation. The control group of cows without the addition of selenium to the diet showed a selenium concentration below the detection limit. During the experiment, milk yield, lactose, fat and protein were not affected. A significant decrease (p <0.05 of somatic cells by 58% occurred in milk in the experimental group. The amount of urea was significantly lower in both groups in the experimental (by 52%; p <0.05 and control (50%; p <0.05. These results show that the addition of selenium may increase

Two wheat glutathione peroxidase genes whose products are located in chloroplasts improve salt and H2O2 tolerances in Arabidopsis.

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Chao-Zeng Zhai

Full Text Available Oxidative stress caused by accumulation of reactive oxygen species (ROS is capable of damaging effects on numerous cellular components. Glutathione peroxidases (GPXs, EC 1.11.1.9 are key enzymes of the antioxidant network in plants. In this study, W69 and W106, two putative GPX genes, were obtained by de novo transcriptome sequencing of salt-treated wheat (Triticum aestivum seedlings. The purified His-tag fusion proteins of W69 and W106 reduced H2O2 and t-butyl hydroperoxide (t-BHP using glutathione (GSH or thioredoxin (Trx as an electron donor in vitro, showing their peroxidase activity toward H2O2 and toxic organic hydroperoxide. GFP fluorescence assays revealed that W69 and W106 are localized in chloroplasts. Quantitative real-time PCR (Q-RT-PCR analysis showed that two GPXs were differentially responsive to salt, drought, H2O2, or ABA. Isolation of the W69 and W106 promoters revealed some cis-acting elements responding to abiotic stresses. Overexpression of W69 and W106 conferred strong tolerance to salt, H2O2, and ABA treatment in Arabidopsis. Moreover, the expression levels of key regulator genes (SOS1, RbohD and ABI1/ABI2 involved in salt, H2O2 and ABA signaling were altered in the transgenic plants. These findings suggest that W69 and W106 not only act as scavengers of H2O2 in controlling abiotic stress responses, but also play important roles in salt and ABA signaling.

Ecological aspects of selenium and tellurium in human and animal health

Energy Technology Data Exchange (ETDEWEB)

Frost, D V; Ingvoldstad, D

1975-01-01

Animal and human studies indicate that selenium inadequacy, in part, underlies various chronic diseases. Epidemiologic evidence suggests that cancer and heart disease are most common where ambient Se availability is low. Plant Se uptake and Se blood levels are inverse to human cancer mortality. As the active group in glutathione peroxidase, Se/sup -2/ inhibits aberrant oxidations which lead to chronic diseases. It binds heavy metals, and with tocopherol maintains tissue integrity. Sulfur dioxide fallout from the atmosphere, resulting from fossil fuel burning, may diminish the nutritional availability of selenium by diminishing plant uptake. Intensive ruminant grazing returns unavailable Se/sup 0/ to soils. Trimethyl selenium ion, as excreted by animals, also appears to be unavailable to plants. Modern fertilization practices and the effect of buildup of sulfates in the soil, due to acid rains, both appear to lessen the availability of Se to plants. SeO/sub 2/ added to the atmosphere from combustion and volcanic activity react with SO/sub 2/ to yield Se/sup 0/. This is presumed to fall out as particles from the air. How traces of Se are otherwise carried in air, explaining its enrichment in some areas, is unknown. The New Zealand experience with Se inadequacy in animals and man may be repeated in other parts of the world. Se inadequacy is far more of a human health problem than Se toxicity. There are no known adverse health effects from tellurium, other than tellurium breath. 164 references, 5 figures, 3 tables.

Treating chronic arsenic toxicity with high selenium lentil diets

Energy Technology Data Exchange (ETDEWEB)

Sah, Shweta [Department of Ecosystem and Public Health, Faculty of Medicine, University of Calgary, Calgary, AB T2N 4Z6 (Canada); Vandenberg, Albert [Department of Plant Sciences, University of Saskatchewan, Saskatoon, SK S7N 5A8 (Canada); Smits, Judit, E-mail: judit.smits@ucalgary.ca [Department of Ecosystem and Public Health, Faculty of Veterinary Medicine, University of Calgary, Calgary, AB T2N 4Z6 (Canada)

2013-10-01

Arsenic (As) toxicity causes serious health problems in humans, especially in the Indo-Gangetic plains and mountainous areas of China. Selenium (Se), an essential micronutrient is a potential mitigator of As toxicity due to its antioxidant and antagonistic properties. Selenium is seriously deficient in soils world-wide but is present at high, yet non-toxic levels in the great plains of North America. We evaluate the potential of dietary Se in counteracting chronic As toxicity in rats through serum biochemistry, blood glutathione levels, immunotoxicity (antibody response), liver peroxidative stress, thyroid response and As levels in tissues and excreta. To achieve this, we compare diets based on high-Se Saskatchewan (SK) lentils versus low-Se lentils from United States. Rats drank control (0 ppm As) or As (40 ppm As) water while consuming SK lentils (0.3 ppm Se) or northwestern USA lentils (< 0.01 ppm Se) diets for 14 weeks. Rats on high Se diets had higher glutathione levels regardless of As exposure, recovered antibody responses in As-exposed group, higher fecal and urinary As excretion and lower renal As residues. Selenium deficiency caused greater hepatic peroxidative damage in the As exposed animals. Thyroid hormones, triiodothyronine (T3) and thyroxine (T4), were not different. After 14 weeks of As exposure, health indicators in rats improved in response to the high Se lentil diets. Our results indicate that high Se lentils have a potential to mitigate As toxicity in laboratory mammals, which we hope will translate into benefits for As exposed humans. - Highlights: • We reduce chronic arsenic toxicity in rats with a whole food solution. • High selenium lentils decrease liver damage and increase blood glutathione levels. • High selenium lentil diets increase urinary and fecal arsenic excretion. • High selenium lentil diets decrease arsenic levels in kidney, the storage organ. • High selenium lentil diets reverse arsenic suppression of the B cell

Treating chronic arsenic toxicity with high selenium lentil diets

International Nuclear Information System (INIS)

Sah, Shweta; Vandenberg, Albert; Smits, Judit

2013-01-01

Arsenic (As) toxicity causes serious health problems in humans, especially in the Indo-Gangetic plains and mountainous areas of China. Selenium (Se), an essential micronutrient is a potential mitigator of As toxicity due to its antioxidant and antagonistic properties. Selenium is seriously deficient in soils world-wide but is present at high, yet non-toxic levels in the great plains of North America. We evaluate the potential of dietary Se in counteracting chronic As toxicity in rats through serum biochemistry, blood glutathione levels, immunotoxicity (antibody response), liver peroxidative stress, thyroid response and As levels in tissues and excreta. To achieve this, we compare diets based on high-Se Saskatchewan (SK) lentils versus low-Se lentils from United States. Rats drank control (0 ppm As) or As (40 ppm As) water while consuming SK lentils (0.3 ppm Se) or northwestern USA lentils (< 0.01 ppm Se) diets for 14 weeks. Rats on high Se diets had higher glutathione levels regardless of As exposure, recovered antibody responses in As-exposed group, higher fecal and urinary As excretion and lower renal As residues. Selenium deficiency caused greater hepatic peroxidative damage in the As exposed animals. Thyroid hormones, triiodothyronine (T3) and thyroxine (T4), were not different. After 14 weeks of As exposure, health indicators in rats improved in response to the high Se lentil diets. Our results indicate that high Se lentils have a potential to mitigate As toxicity in laboratory mammals, which we hope will translate into benefits for As exposed humans. - Highlights: • We reduce chronic arsenic toxicity in rats with a whole food solution. • High selenium lentils decrease liver damage and increase blood glutathione levels. • High selenium lentil diets increase urinary and fecal arsenic excretion. • High selenium lentil diets decrease arsenic levels in kidney, the storage organ. • High selenium lentil diets reverse arsenic suppression of the B cell

Effect of selenium nanoparticles with different sizes in primary cultured intestinal epithelial cells of crucian carp, Carassius auratus gibelio

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Wang YB

2013-10-01

Full Text Available Yanbo Wang, Xuxia Yan, Linglin Fu Marine Resources and Nutrition Biology Research Center, Food Quality and Safety Department, Zhejiang Gongshang University, Hangzhou, People's Republic of China Abstract: Nano-selenium (Se, with its high bioavailability and low toxicity, has attracted wide attention for its potential application in the prevention of oxidative damage in animal tissues. However, the effect of nano-Se of different sizes on the intestinal epithelial cells of the crucian carp (Carassius auratus gibelio is poorly understood. Our study showed that different sizes and doses of nano-Se have varied effects on the cellular protein contents and the enzyme activities of secreted lactate dehydrogenase, intracellular sodium potassium adenosine triphosphatase, glutathione peroxidase, and superoxide dismutase. It was also indicated that nano-Se had a size-dependent effect on the primary intestinal epithelial cells of the crucian carp. Thus, these findings may bring us a step closer to understanding the size effect and the bioavailability of nano-Se on the intestinal tract of the crucian carp. Keywords: selenium nanoparticle, intestinal epithelial cell, crucian carp, primary culture

Glutathione Peroxidase-1 Suppresses the Unfolded Protein Response upon Cigarette Smoke Exposure

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Patrick Geraghty

2016-01-01

Full Text Available Oxidative stress provokes endoplasmic reticulum (ER stress-induced unfolded protein response (UPR in the lungs of chronic obstructive pulmonary (COPD subjects. The antioxidant, glutathione peroxidase-1 (GPx-1, counters oxidative stress induced by cigarette smoke exposure. Here, we investigate whether GPx-1 expression deters the UPR following exposure to cigarette smoke. Expression of ER stress markers was investigated in fully differentiated normal human bronchial epithelial (NHBE cells isolated from nonsmoking, smoking, and COPD donors and redifferentiated at the air liquid interface. NHBE cells from COPD donors expressed heightened ATF4, XBP1, GRP78, GRP94, EDEM1, and CHOP compared to cells from nonsmoking donors. These changes coincided with reduced GPx-1 expression. Reintroduction of GPx-1 into NHBE cells isolated from COPD donors reduced the UPR. To determine whether the loss of GPx-1 expression has a direct impact on these ER stress markers during smoke exposure, Gpx-1−/− mice were exposed to cigarette smoke for 1 year. Loss of Gpx-1 expression enhanced cigarette smoke-induced ER stress and apoptosis. Equally, induction of ER stress with tunicamycin enhanced antioxidant expression in mouse precision-cut lung slices. Smoke inhalation also exacerbated the UPR response during respiratory syncytial virus infection. Therefore, ER stress may be an antioxidant-related pathophysiological event in COPD.

Association of antioxidative enzymes with the synergistic effect of selenium and UV irradiation in enhancing plant growth

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T. XUE

2008-12-01

Full Text Available Selenium (Se is able to defend human and animal cells against UV(B stress. Higher plants are generally considered not to require Se but to have a low tolerance to it. However, recently it has been demonstrated that Se is able to protect also plants against UV-induced oxidative stress and even to promote the growth of plants subjected to high-energy light. In the present study the effects of Se on antioxidative enzymes possibly associated with this synergistic effect were investigated. Ryegrass and lettuce were grown in soil supplemented with Se at 0, 0.1 or 1.0 mg kg-1 under normal light or subjected to UV episodes. Lipid peroxidation and the changes of antioxidative enzymes were measured at two growing stages. The positive synergistic effect of the lower Se dosage and UV was found to be at least partly associated with the antioxidative role of Se through increased glutathione peroxidase (GSH-Px and catalase (CAT activity, whereas ascorbate peroxidase (APX responded negatively to both factors. The contribution of the other enzymes studied seemed to be plant-specific: glutathione S-transferase (GST increased in both ryegrass assays and superoxide dismutase (SOD in the first lettuce assay. At the higher addition level Se acted as a pro-oxidant and diminished fresh weight yields. UV irradiation alleviated the toxicity coincidently with increase of CAT in ryegrass and SOD in lettuce.;

Trace elements profile is associated with insulin resistance syndrome and oxidative damage in thyroid disorders: Manganese and selenium interest in Algerian participants with dysthyroidism.

Science.gov (United States)

Maouche, Naima; Meskine, Djamila; Alamir, Barkahoum; Koceir, Elhadj-Ahmed

2015-10-01

The relationship between dysthyroidism and antioxidant trace elements (ATE) status is very subtle during oxidative stress (OS). This relationship is mediated by thyroid hormone (TH) disorder, insulin resistance syndrome (IRS) and inflammation. The aim of this study was to investigate ATE such as selenium (Se), manganese (Mn), zinc (Zn) and copper (Cu) status on thyroid dysfunction, and their interaction with antioxidant enzyme activities, mainly, superoxide dismutase (SOD) and glutathione peroxidase (GPx), TH profile (TSH, T(3), T(4)) and IRS clusters. The study was undertaken on 220 Algerian adults (30-50 years), including 157 women and 63 men who were divided to 4 groups: subclinical hypothyroidism (n = 50), overt hypothyroidism (n = 60), Graves's disease hyperthyroidism (n = 60) and euthyroid controls (n = 50). The IRS was confirmed according to NCEP (National Cholesterol Education Program). Insulin resistance was evaluated by HOMA-IR model. Trace elements were determined by the Flame Atomic Absorption Spectrometry (Flame-AAS) technique. The antioxidant enzymes activity and metabolic parameters were determined by biochemical methods. The TH profile and anti-Thyroperoxidase Antibodies (anti-TPO-Ab) were evaluated by radioimmunoassay. Results showed that the plasma manganese levels were significantly increased in all dysthyroidism groups (p ≤ 0.01). However, the plasma copper and zinc concentrations were maintained normal or not very disturbed vs control group. In contrast, the plasma selenium levels were highly decreased (p ≤ 0.001) and positively correlated with depletion of glutathione peroxidase activity; and associated both with anti-TPO-Ab overexpression and fulminant HS-CRP levels. This study confirms the oxidative stress-inflammation relationship in the dysthyroidism. The thyroid follicles antioxidant protection appears preserved in the cytosol (Cu/Zn-SOD), while it is altered in the mitochondria (Mn-SOD), which gives this cell organelle, a status of

Influence the oxidant action of selenium in radiosensitivity induction and cell death in yeast Saccharomyces cerevisiae

International Nuclear Information System (INIS)

Porto, Barbara Abranches de Araujo

2012-01-01

Ionizing radiations are from both natural sources such as from anthropogenic sources. Recently, radiotherapy has emerged as one of the most common therapies against cancer. Co-60 irradiators (cobalt-60 linear accelerators) are used to treat of malignant tumors routinely in hospitals around the world. Exposure to ionizing radiation can induce changes in cellular macromolecules and affect its functions, because they cause radiolysis of the water molecule generating reactive oxygen species, which can cause damage to virtually all organelles and cell components known as oxidative damage that can culminate in oxidative stress. Oxidative stress is a situation in which the balance between oxidants and antioxidants is broken resulting in excessive production of reactive species, it is not accompanied by the increase in antioxidant capacity, making it impossible to neutralize them. Selenium is a micronutrient considered as antioxidant, antiinflammatory, which could prevent cancer. Selenium in biological system exists as seleno proteins. Nowadays, 25 human seleno proteins have been identified, including glutathione peroxidase, an antioxidant enzyme. Yeasts have the ability to incorporate various metals such as iron, cadmium, zinc and selenium, as well as all biological organisms. The yeast Saccharomyces cerevisiae, unlike mammalian cells is devoid of seleno proteins, being considered as a practical model for studies on the toxicity of selenium, without any interference from the metabolism of seleno proteins. Moreover, yeast cells proliferate through the fermentation, the microbial equivalent of aerobic glycolysis in mammals and the process is also used by tumors. Several reports show that the pro-oxidante effects and induced toxic selenium compounds occur at lower doses and in malignant cells compared with benign cells. Therefore selenium giving a great therapeutic potential in cancer treatment .Our objective was to determine whether selenium is capable to sensitize yeasts

Cloning and characterization of an ascorbate peroxidase gene ...

African Journals Online (AJOL)

DR. NJ TONUKARI

2012-05-29

May 29, 2012 ... Real-time quantitative polymerase chain reaction was used to explore expression patterns of. MaAPX1 in ... and the activity of a number of enzymatic systems, including ... peroxidase (APX), glutathione reductase and catalase.

A systematic approach to the accurate quantification of selenium in serum selenoalbumin by HPLC-ICP-MS

International Nuclear Information System (INIS)

Jitaru, Petru; Goenaga-Infante, Heidi; Vaslin-Reimann, Sophie; Fisicaro, Paola

2010-01-01

In this paper, two different methods are for the first time systematically compared for the determination of selenium in human serum selenoalbumin (SeAlb). Firstly, SeAlb was enzymatically hydrolyzed and the resulting selenomethionine (SeMet) was quantified using species-specific isotope dilution (SSID) with reversed phase-HPLC (RP-HPLC) hyphenated to (collision/reaction cell) inductively coupled plasma-quadrupole mass spectrometry (CRC ICP-QMS). In order to assess the enzymatic hydrolysis yield, SeAlb was determined as an intact protein by affinity-HPLC (AF-HPLC) coupled to CRC ICP-QMS. Using this approach, glutathione peroxidase (GPx) and selenoprotein P (SelP) (the two selenoproteins present in serum) were also determined within the same chromatographic run. The levels of selenium associated with SeAlb in three serum materials, namely BCR-637, Seronorm level 1 and Seronorm level 2, obtained using both methods were in a good agreement. Verification of the absence of free SeMet, which interferes with the SeAlb determination (down to the amino acid level), in such materials was addressed by analyzing the fraction of GPx, partially purified by AF-HPLC, using RP-HPLC (GPx only) and size exclusion-HPLC (SE-HPLC) coupled to CRC ICP-QMS. The latter methodology was also used for the investigation of the presence of selenium species other than the selenoproteins in the (AF-HPLC) SelP and SeAlb fractions; the same selenium peaks were detected in both control and BCR-637 serum with a difference in age of ca. 12 years. It is also for the first time that the concentrations of selenium associated with SeAlb, GPx and SelP species in such commercially available serums (only certified or having indicative levels of total selenium content) are reported. Such indicative values can be used for reference purposes in future validation of speciation methods for selenium in human serum and/or inter-laboratory comparisons.

A systematic approach to the accurate quantification of selenium in serum selenoalbumin by HPLC-ICP-MS

Energy Technology Data Exchange (ETDEWEB)

Jitaru, Petru, E-mail: Petru.Jitaru@lne.fr [Laboratoire National de Metrologie et d' Essais (LNE), Department of Biomedical and Inorganic Chemistry, 1 rue Gaston Boissier, 75015 Paris (France); Goenaga-Infante, Heidi [LGC Limited, Queens Road, Teddington, TW11 OLY, Middlesex (United Kingdom); Vaslin-Reimann, Sophie; Fisicaro, Paola [Laboratoire National de Metrologie et d' Essais (LNE), Department of Biomedical and Inorganic Chemistry, 1 rue Gaston Boissier, 75015 Paris (France)

2010-01-11

In this paper, two different methods are for the first time systematically compared for the determination of selenium in human serum selenoalbumin (SeAlb). Firstly, SeAlb was enzymatically hydrolyzed and the resulting selenomethionine (SeMet) was quantified using species-specific isotope dilution (SSID) with reversed phase-HPLC (RP-HPLC) hyphenated to (collision/reaction cell) inductively coupled plasma-quadrupole mass spectrometry (CRC ICP-QMS). In order to assess the enzymatic hydrolysis yield, SeAlb was determined as an intact protein by affinity-HPLC (AF-HPLC) coupled to CRC ICP-QMS. Using this approach, glutathione peroxidase (GPx) and selenoprotein P (SelP) (the two selenoproteins present in serum) were also determined within the same chromatographic run. The levels of selenium associated with SeAlb in three serum materials, namely BCR-637, Seronorm level 1 and Seronorm level 2, obtained using both methods were in a good agreement. Verification of the absence of free SeMet, which interferes with the SeAlb determination (down to the amino acid level), in such materials was addressed by analyzing the fraction of GPx, partially purified by AF-HPLC, using RP-HPLC (GPx only) and size exclusion-HPLC (SE-HPLC) coupled to CRC ICP-QMS. The latter methodology was also used for the investigation of the presence of selenium species other than the selenoproteins in the (AF-HPLC) SelP and SeAlb fractions; the same selenium peaks were detected in both control and BCR-637 serum with a difference in age of ca. 12 years. It is also for the first time that the concentrations of selenium associated with SeAlb, GPx and SelP species in such commercially available serums (only certified or having indicative levels of total selenium content) are reported. Such indicative values can be used for reference purposes in future validation of speciation methods for selenium in human serum and/or inter-laboratory comparisons.

Journal of Chemical Sciences | Indian Academy of Sciences

Indian Academy of Sciences (India)

The application of intramolecular coordination in the isolation of novel diaryl diselenides and their derivatives, monomeric chalcogenolato complexes of group 12 metals, glutathione peroxidase mimics, hybrid bi-, tri- and multidentate ligands and selenium-containing azamacrocycles is described.

Seasonal mercury exposure and oxidant-antioxidant status of James Bay sport fishermen.

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Bélanger, Marie-Claire; Mirault, Marc-Edouard; Dewailly, Eric; Plante, Michel; Berthiaume, Line; Noël, Micheline; Julien, Pierre

2008-05-01

The effects of a moderate seasonal exposure to methylmercury on plasma low-density lipoprotein (LDL) oxidation and cardiovascular risk indices are not known. The objective of the study was to assess the effects of a seasonal exposure to mercury at similar dose reported to increase cardiovascular risk through fish consumption. Effects on lipoprotein cholesterol and fatty acid profiles, LDL oxidation, and blood oxidant-antioxidant balance were to be assessed in sport fishermen presenting normal blood selenium and omega-3 fatty acid contents. Thirty-one healthy James Bay sport fishermen were assessed for within-subject longitudinal seasonal variations in hair and blood mercury, plasma oxidized LDL, lipophilic antioxidants, homocysteine, blood selenium, and glutathione peroxidase and reductase activities determined before and after the fishing season and compared by matched-pair tests. Hair mercury doubled during the fishing season (2.8+/-0.4 microg/g, P<.0001). Baseline blood selenium, homocysteine, and erythrocyte fatty acid profiles did not change. Plasma high-density lipoprotein cholesterol increased (+5%, P=.05), whereas very low-density lipoprotein cholesterol and oxidized LDL decreased (-8%, P=.05; -18%, P=.008). Blood glutathione peroxidase (+9.7%, P=.001), glutathione reductase (+7.2%, P<.0001), and total glutathione (+45% P<.0001) increased during the fishing season. Plasma total coenzyme Q10 (+13%, P=.02), ubiquinone-10 (+67%, P=.03), and beta-carotene (+46%, P=.01) also increased, whereas vitamin E status was unaffected. Pairwise correlations revealed no association between mercury exposure and any of the biomarkers investigated. In contrast, strong predictors of cardiovascular risk such as high-density lipoprotein cholesterol, oxidized LDL, and glutathione peroxidase improved during the fishing season despite elevated methylmercury exposure. The beneficial effects of seasonal fishing activity and fish consumption on cardiovascular health may suppress

Effect of selenium-saturated bovine lactoferrin (Se-bLF) on antioxidant enzyme activities in human gut epithelial cells under oxidative stress.

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Burrow, Hannah; Kanwar, Rupinder K; Mahidhara, Ganesh; Kanwar, Jagat R

2011-10-01

Cancer and many chronic inflammatory diseases are associated with increased amounts of reactive oxygen species (ROS). The potential cellular and tissue damage created by ROS has significant impact on many disease and cancer states and natural therapeutics are becoming essential in regulating altered redox states. We have shown recently that iron content is a critical determinant in the antitumour activity of bovine milk lactoferrin (bLF). We found that 100% iron-saturated bLF (Fe-bLF) acts as a potent natural adjuvant and fortifying agent for augmenting cancer chemotherapy and thus has a broad utility in the treatment of cancer. Furthermore, we also studied the effects of iron saturated bLF's ability as an antioxidant in the human epithelial colon cancer cell line HT29, giving insights into the potential of bLF in its different states. Thus, metal saturated bLF could be implemented as anti-cancer neutraceutical. In this regard, we have recently been able to prepare a selenium (Se) saturated form of bLF, being up to 98% saturated. Therefore, the objectives of this study were to determine how oxidative stress induced by hydrogen peroxide (H2O2) alters antioxidant enzyme activity within HT29 epithelial colon cancer cells, and observe changes in this activity by treatments with different antioxidants ascorbic acid (AA), Apo (iron free)-bLF and selenium (Se)-bLF. The states of all antioxidant enzymes (glutathione peroxidase (GPx), glutathione reductase (GR), glutathione- s-transferase (GsT), catalase and superoxide dismutase (SOD)) demonstrated high levels within untreated HT29 cells compared to the majority of other treatments being used, even prior to H2O2 exposure. All enzymes showed significant alterations in activity when cells were treated with antioxidants AA, Apo-bLF or Se-bLF, with and/or without H2O2 exposure. Obvious indications that the Se content of the bLF potentially interacted with the glutathione (GSH)/GPx/GR/GsT associated redox system could be

Indications of selenium protection against cadmium and lead toxicity in oilseed rape (Brassica napus L.

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Zhilin Wu

2016-12-01

Full Text Available The present study investigated the beneficial role of selenium (Se in protecting oilseed rape (Brassica napus L. plants from cadmium (Cd+2 and lead (Pb+2 toxicity. Exogenous Se markedly reduced Cd and Pb concentration in both roots and shoots. Supplementation of the medium with Se (5, 10 and 15 mg kg-1 alleviated the negative effect of Cd and Pb on growth and led to a decrease in oxidative damages caused by Cd and Pb. Furthermore, Se enhanced superoxide free radicals (O2-, hydrogen peroxide (H2O2 and lipid peroxidation, as indicated by malondialdehyde (MDA accumulation, but decreased superoxide dismutase (SOD and glutathione peroxidase (GPx activities. Meanwhile, the presence of Cd and Pb in the medium affected Se speciation in shoots. The results suggest that Se could alleviate Cd and Pb toxicity by preventing oxidative stress in oilseed rape plant.

The effect of intermittent hypobaric-hypoxia treatments on renal glutathione peroxidase activity of rats

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Paramita, I. A.; Jusman, S. W. A.

2017-08-01

Many people living at high altitudes experiencing a condition called intermittent hypobaric hypoxia (IHH). Some people even create IHH condition as an exercise for pilots, athletes, and mountaineers. In this experiment, we aimed to determine whether the protective effect of IHH is mediated through glutathione peroxidase (GPX) enzyme. The experiment’s sample is two-month-old healthy Sprague-Dawley rat kidneys weighing 200-250 g. Intermittent hypobaric hypoxia treatment is done using a Hypobaric Chamber type I that can mimic air pressure at certain altitudes: 35,000 (one minute), 30,000 (three minutes), 25,000 (five minutes), and 18,000 (30 minutes) feet. The rats were divided into five treatment groups, including a control group, hypobaric-hypoxia group, and intermittent hypobaric-hypoxia 1x, 2x, and 3x groups with each group consisting of three rats. The specific activity of GPX was measured using RANDOX and RANSEL methods. The statistical analysis of one way-ANOVA did not show significant differences between the groups (p > 0.05), although specific activities of the renal GPX of rats exposed to hypobaric-hypoxia were higher than the control group. This may be caused by the other antioxidants’ activities. In conclusion, the IHH treatment did not affect GPX activity in the rat kidneys.

Selenium deficiency occurs in some patients with moderate-to-severe cirrhosis and can be corrected by administration of selenate but not selenomethionine: a randomized controlled trial123

Science.gov (United States)

Burk, Raymond F; Hill, Kristina E; Motley, Amy K; Byrne, Daniel W; Norsworthy, Brooke K

2015-01-01

Background: Selenomethionine, which is the principal dietary form of selenium, is metabolized by the liver to selenide, which is the form of the element required for the synthesis of selenoproteins. The liver synthesizes selenium-rich selenoprotein P (SEPP1) and secretes it into the plasma to supply extrahepatic tissues with selenium. Objectives: We conducted a randomized controlled trial to determine whether cirrhosis is associated with functional selenium deficiency (the lack of selenium for the process of selenoprotein synthesis even though selenium intake is not limited) and, if it is, whether the deficiency is associated with impairment of selenomethionine metabolism. Design: Patients with Child-Pugh (C-P) classes A, B, and C (mild, moderate, and severe, respectively) cirrhosis were supplemented with a placebo or supranutritional amounts of selenium as selenate (200 or 400 μg/d) or as selenomethionine (200 μg/d) for 4 wk. Plasma SEPP1 concentration and glutathione peroxidase (GPX) activity, the latter due largely to the selenoprotein GPX3 secreted by the kidneys, were measured before and after supplementation. Results: GPX activity was increased more by both doses of selenate than by the placebo in C-P class B patients. The activity was not increased more by selenomethionine supplementation than by the placebo in C-P class B patients. Plasma selenium was increased more by 400 μg Se as selenate than by the placebo in C-P class C patients. Within the groups who responded to selenate, there was a considerable variation in responses. Conclusion: These results indicate that severe cirrhosis causes mild functional selenium deficiency in some patients that is associated with impaired metabolism of selenomethionine. This trial was registered at clinicaltrials.gov as NCT00271245. PMID:26468123

Comparison of anti-oxidant enzymes activity and levels of zinc and selenium in sperm and seminal plasma between fertile and idiopathic infertile men

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Hadi Kharazi

2010-12-01

Full Text Available Background: Reactive oxygen species (ROS-induced lipidperoxidation can lead to dysfunction of sperm and thereby, infertility may be occurred. So, always there is a balance between amount of ROS and anti-oxidant molecules in semen. Anti-oxidant enzymes of sperm; superoxide dismutase (SOD, glutathione peroxidase (GPX, catalse and zinc and selenium can protect it from destructive effects of ROS. Hence, the present study was designed to compare the activities of these enzymes and trace elements between fertile and idiopathic infertile men.Methods: Semen specimens were collected from 30 infertile men with proven infertility by an urologist, and 30 fertile men as control donors, with age range between 20-40 years old. Semen analysis was conducted by CASA method. Atomic absorption method was used for measuring of zinc and selenium concentration. Activity assays of SOD and GPX were performed by Randox Kits. Aebi method also was applied for evaluation of catalase activity.Results: There was no difference between the activities of enzymes in fertile men and infertile ones. Also, it wasn't seen any difference in the selenium and zinc levels of seminal plasma. There was no relationship between evaluated items with sperm parameters. Only, in asthenoteratospermic individuals negative correlations were found between GPX and sperm motility, selenium and sperm morphology. Also, in these individuals ,there was a positive correlation between SOD and catalse activity.Conclusion: Measuring activities of SOD, GPx, and catalase and the contents of zinc and selenium of seminal plasma do not appear to be suitable tools for determining the fertility potential of sperm.

Characterization of glutathione peroxidase diversity in the symbiotic sea anemone Anemonia viridis.

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Pey, Alexis; Zamoum, Thamilla; Christen, Richard; Merle, Pierre-Laurent; Furla, Paola

2017-01-01

Cnidarians living in symbiosis with photosynthetic dinoflagellates (commonly named zooxanthellae) are exposed to high concentrations of reactive oxygen species (ROS) upon illumination. To quench ROS production, both the cnidarian host and zooxanthellae express a full suite of antioxidant enzymes. Studying antioxidative balance is therefore crucial to understanding how symbiotic cnidarians cope with ROS production. We characterized glutathione peroxidases (GPx) in the symbiotic cnidarian Anemonia viridis by analysis of their isoform diversity, their activity distribution in the three cellular compartments (ectoderm, endoderm and zooxanthellae) and their involvement in the response to thermal stress. We identified a GPx repertoire through a phylogenetic analysis showing 7 GPx transcripts belonging to the A. viridis host and 4 GPx transcripts strongly related to Symbiodinium sp. The biochemical approach, used for the first time with a cnidarian species, allowed the identification of GPx activity in the three cellular compartments and in the animal mitochondrial fraction, and revealed a high GPx electrophoretic diversity. The symbiotic lifestyle of zooxanthellae requires more GPx activity and diversity than that of free-living species. Heat stress induced no modification of GPx activities. We highlight a high GPx diversity in A. viridis tissues by genomic and biochemical approaches. GPx activities represent an overall constitutive enzymatic pattern inherent to symbiotic lifestyle adaptation. This work allows the characterization of the GPx family in a symbiotic cnidarian and establishes a foundation for future studies of GPx in symbiotic cnidarians. Copyright © 2016 Elsevier B.V. and Société Française de Biochimie et Biologie Moléculaire (SFBBM). All rights reserved.

Effect of long term selenium yeast intervention on activity and gene expression of antioxidant and xenbiotic metabolising enzymes in healthy elderly volunteers from the Danish Prevention of Cancer by Intervention by Selenium (PRECISE) Pilot Study

DEFF Research Database (Denmark)

Ravn-Haren, Gitte; Krath, Britta; Overvad, Kim

2008-01-01

Numerous mechanisms have been proposed to explain the anti-carcinogenic effects of Se, among them altered carcinogen metabolism. We investigated the effect of Se supplementation on activities of glutathione peroxidase (GPX), glutathione reductase (GR) and glutathione S-transferase (GST...

Selective inhibition of endogenous antioxidants with Auranofin causes mitochondrial oxidative stress which can be countered by selenium supplementation.

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Radenkovic, Filip; Holland, Olivia; Vanderlelie, Jessica J; Perkins, Anthony V

2017-12-15

Auranofin is a thiol-reactive gold (I)-containing compound with potential asa chemotherapeutic. Auranofin has the capacity to selectively inhibit endogenous antioxidant enzymes thioredoxin reductase (TrxR) and glutathione peroxidase (GPx), resulting in oxidative stress and the initiation of a pro-apoptotic cascade. The effect of Auranofin exposure on TrxR and GPx, and the potential for cellular protection through selenium supplementation was examined in the non-cancerous human cell line Swan-71. Auranofin exposure resulted in a concentration dependent differential inhibition of selenoprotein antioxidants. Significant inhibition of TrxR was observed at 20nM Auranofin with inhibition of GPx from 10µM. Significant increases in reactive oxygen species (ROS) were associated with antioxidant inhibition at Auranofin concentrations of 100nM (TrxR inhibition) and 10µM (TrxR and GPx inhibition), respectively. Evaluation of mitochondrial respiration demonstrated significant reductions in routine and maximal respiration at both 100nM and 10μM Auranofin. Auranofin treatment at concentrations of 10μM and higher concentrations resulted in a ∼68% decrease in cellular viability and was associated with elevations in pro-apoptotic markers cytochrome c flux control factor (FCFc) at concentration of 100nM and mitochondrial Bax at 10μM. The supplementation of selenium (100nM) prior to treatment had a generalized protective affect through the restoration of antioxidant activity with a significant increase in TrxR and GPx activity, a significant reduction in ROS and associated improvement in mitochondrial respiration and cellular viability (10µM ∼48% increase). Selenium supplementation reduced the FCFc at low doses of Auranofin (selenium exposure. Therefore, Auranofin dose and the selenium status of patients are important considerations in the therapeutic use of Auranofin as an agent of chemosensitization. Crown Copyright © 2017. Published by Elsevier Inc. All rights reserved.

The role of folic acid and selenium against oxidative damage from ethanol in early life programming: a review.

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Ojeda, Luisa; Nogales, Fátima; Murillo, Luisa; Carreras, Olimpia

2018-04-01

There are disorders in children, covered by the umbrella term "fetal alcohol spectrum disorder" (FASD), that occur as result of alcohol consumption during pregnancy and lactation. They appear, at least in part, to be related to the oxidative stress generated by ethanol. Ethanol metabolism generates reactive oxygen species and depletes the antioxidant molecule glutathione (GSH), leading to oxidative stress and lipid and protein damage, which are related to growth retardation and neurotoxicity, thereby increasing the incidence of FASD. Furthermore, prenatal and postnatal exposure to ethanol in dams, as well as increasing oxidation in offspring, causes malnutrition of several micronutrients such as the antioxidant folic acid and selenium (Se), affecting their metabolism and bodily distribution. Although abstinence from alcohol is the only way to prevent FASD, it is possible to reduce its harmful effects with a maternal dietary antioxidant therapy. In this review, folic acid and Se have been chosen to be analyzed as antioxidant intervention systems related to FASD because, like ethanol, they act on the methionine metabolic cycle, being related to the endogenous antioxidants GSH and glutathione peroxidase. Moreover, several birth defects are related to poor folate and Se status.

Dietary fish oil replacement with palm or poultry oil increases fillet oxidative stability and decreases liver glutathione peroxidase activity in barramundi (Lates calcarifer).

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Wan Ahmad, Wan A R; Stone, David A J; Schuller, Kathryn A

2013-12-01

Complete dietary fish oil replacement with palm or poultry oil in barramundi (Lates calcarifer) had no detrimental effects on growth or hepatosomatic index of juvenile fish up to an average size of ~50 g. However, it significantly decreased the omega-3 (n-3) long-chain polyunsaturated fatty acid content of the fish muscle (fillet) lipids. This was particularly true for eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) which are recognised for their health beneficial effects in the human diet. As a result of their decreased EPA and DHA content, the peroxidation index of the muscle lipids was also decreased. This was associated with increased simulated retail storage shelf life as indicated by decreased thiobarbituric acid reactive substances in muscle samples from fish fed the palm or poultry oil-based diets. Concomitantly, glutathione peroxidase (GPx) activity, but not glutathione S-transferase (GST) activity or reduced glutathione concentration, was significantly reduced in the liver of barramundi fed the palm or poultry oil-based diets as compared with the fish fed the fish oil-based diet. Furthermore, GPx and GST activity were very low in muscle, much lower than in gastrointestinal tract, liver or swim bladder. Therefore, we propose that liver GPx activity may be a good predictor of fillet shelf life in barramundi and other fish species.

Glutathione content in sperm cells of infertile men

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R. V. Fafula

2017-04-01

Full Text Available Hyperproduction of reactive oxygen species can damage sperm cells and is considered to be one of the mechanisms of male infertility. Cell protection from the damaging effects of free radicals and lipid peroxidation products is generally determined by the degree of antioxidant protection. Glutathione is non-enzymatic antioxidant which plays an important protective role against oxidative damages and lipid peroxidation. The aim of the present work is to determine the content of reduced and oxidized glutathione in sperm cells of infertile men. Semen samples from 20 fertile men (normozoospermics and 72 infertile patients (12 oligozoospermics, 17 asthenozoospermics, 10 oligoasthenozoosper­mics and 33 leucocytospermic were used. The total, oxidized (GSSG and reduced (GSH glutathione levels were measured spectrophotometrically. The levels of total glutathione were significantly lower in the spermatozoa of patients with oligozoo-, asthenozoo- and oligoasthenozoospermia than in the control. Infertile groups showed significantly decreased values of reduced glutathione in sperm cells vs. fertile men, indicating an alteration of oxidative status. The oxidized glutathione levels in sperm cells of infertile men did not differ from those of normozoospermic men with proven fertility. The GSH/GSSG ratio was significantly decreased in the oligo-, astheno- and oligoasthenozoospermic groups compared to the normozoospermic group. In patients with leucocytospermia the GSH/GSSG ratio was lower but these changes were not significant. In addition, glutathione peroxidase activity in sperm cells was decreased in patients with oligozoo-, astenozoo-, oligoastenozoospermia and with leucocytospermia. The most significant changes in glutathione peroxidase activity were observed in infertile men with leucocytospermia. Decreased GSH/GSSG ratio indicates a decline in redox-potential of the glutathione system in sperm cells of men with decreased fertilizing potential

Selol, an organic selenium donor, prevents lipopolysaccharide-induced oxidative stress and inflammatory reaction in the rat brain.

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Dominiak, Agnieszka; Wilkaniec, Anna; Jęśko, Henryk; Czapski, Grzegorz A; Lenkiewicz, Anna M; Kurek, Eliza; Wroczyński, Piotr; Adamczyk, Agata

2017-09-01

Neuroinflammation and oxidative stress are key intertwined pathological factors in many neurological, particularly neurodegenerative diseases, such as Alzheimer's and Parkinson's disorders as well as autism. The present study was conducted to evaluate the protective effects of Selol, an organic selenium donor, against lipopolysaccharide (LPS)-mediated inflammation in rat brain. The results demonstrated that the peripheral administration of LPS in a dose of 100 μg/kg b.w. evoked typical pathological reaction known as systemic inflammatory response. Moreover, we observed elevated blood levels of thiobarbituric acid-reactive substances (TBARS), a marker of oxidative stress, as well as increased concentration of tumor necrosis factor-α (TNF-α) in LPS-treated animals. Selol significantly prevented these LPS-evoked changes. Subsequently, Selol protected against LPS-induced up-regulation of proinflammatory cytokines (Tnfa, Ifng, Il6) in rat brain cortex. The molecular mechanisms through which Selol prevented the neuroinflammation were associated with the inhibition of oxidized glutathione (GSSG) accumulation and with an increase of glutathione-associated enzymes: glutathione peroxidase (Se-GPx), glutathione reductase (GR) as well as thioredoxin reductase (TrxR) activity and expression. Finally, we observed that Selol administration effectively protected against LPS-induced changes in the expression of brain-derived neurotrophic factor (Bdnf). In conclusion, our studies indicated that Selol effectively protects against LPS-induced neuroinflammation by inhibiting pro-inflammatory cytokine release, by boosting antioxidant systems, and by augmenting BDNF level. Therefore, Selol could be a multi-potent and effective drug useful in the treatment and prevention of brain disorders associated with neuroinflammation. Copyright © 2017 Elsevier Ltd. All rights reserved.

Ebselen (PZ-51) protects the Caudate putamen against hypoxia/ischemia induced neuronal damage.

NARCIS (Netherlands)

Knollema, S; Elting, JW; Dijkhuizen, RM; Nicolay, K; Korf, J; TerHorst, GJ

1996-01-01

Ebselen, a synthetic selenium-containing compound which exhibits glutathione peroxidase-like activity in vivo, is known for its beneficial effects on inflammation and tissue injury. Experiments were conducted to test whether ebselen dissolved in DiMethylSulfOxide (DMSO) could prevent damage in a rat

Ebselen (PZ-51) protects the caudate putamen against hypoxia/ischemia induced neuronal damage

NARCIS (Netherlands)

Knollema, S.; Elting, J.W.; Dijkhuizen, R.M.; Nicolaij, K.; Korf, J.; Horst, ter G.J.

1996-01-01

Ebselen, a synthetic selenium-containing compound which exhibits glutathione peroxidase-like activity in vivo, is known for its beneficial effects on inflammation and tissue injury. Experiments were conducted to test whether ebselen dissolved in DiMethylSulfOxide (DMSO) could prevent damage in a rat

Selenium antagonizes cadmium-induced apoptosis in chicken spleen but not involving Nrf2-regulated antioxidant response.

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Chen, Menghao; Li, Xiaojing; Fan, Ruifeng; Cao, Changyu; Yao, Haidong; Xu, Shiwen

2017-11-01

The nuclear transcription factor NF-E2-related factor 2 (Nrf2) binds to antioxidant response elements (AREs) and is involved in the regulation of genes participated in defending cells against oxidative damage, which have been confirmed in animal models. Selenium (Se), known as an important element in the regulation of antioxidant activity, can antagonize Cadmium (Cd) toxicity in birds. However, the role of Nrf2 in selenium-cadmium interaction has not been reported in birds. To further explore the mechanism of selenium attenuating spleen toxicity induced by cadmium in chickens, cadmium chloride (CdCl 2 , 150mg/kg) and sodium selenite (Na 2 SeO 3 , 2mg/kg) were co-administrated or individually administered in the diet of chickens for 90 days. The results showed that Cd exposure increased the level of hydrogen peroxide (H 2 O 2 ) and malondialdehyde (MDA) and decreased the antioxidant enzyme activities, including superoxide dismutase (SOD), glutathione peroxidase (Gpx), total antioxidative capacity (T-AOC), catalase (CAT). Cd exposure increased obviously nuclear accumulation of Nrf2, and the expression of Nrf2 downstream heme oxygenase-1 (HO-1) and NAD(P)H: quinine oxidoreductase 1 (NQO1), reduced the expression of Kelch-like ECH-associated protein (keap1), Gpx-1 and thioredoxin reductase-1 (TrxR1). In addition, Cd induced the increase of bak, caspase9, p53, Cyt c mRNA levels, increased bax/bcl-2 ratio, increased caspase3 mRNA and protein levels. Selenium treatment reduced the accumulation of Cd in the spleen, attenuates Cd-induced Nrf2 nuclear accumulation, enhanced antioxidant enzyme activities, ameliorated Cd-induced oxidative stress and apoptosis in the spleen. In summary, our results demonstrate that Se ameliorated spleen toxicity induced by cadmium by modulating the antioxidant system, independently of Nrf2-regulated antioxidant response pathway. Copyright © 2017 Elsevier Inc. All rights reserved.

Selenium in Skeletal Remains

Czech Academy of Sciences Publication Activity Database

Smrčka, V.; Edriss, A.; Korunová, Vlasta; Dobisíková, M.; Zocová, J.

2011-01-01

Roč. 21, č. 4 (2011), s. 456-463 ISSN 1047-482X R&D Projects: GA ČR GA203/09/1783 Institutional research plan: CEZ:AV0Z40310501 Keywords : trace elements * glutathione-peroxidase * seleniferous area Subject RIV: AC - Archeology, Anthropology, Ethnology Impact factor: 0.955, year: 2011 http://onlinelibrary.wiley.com/doi/10.1002/oa.1152/pdf

Low activity of superoxide dismutase and high activity of glutathione reductase in erythrocytes from centenarians

DEFF Research Database (Denmark)

Andersen, Helle Raun; Jeune, B; Nybo, H

1998-01-01

aged between 60 and 79 years. MEASUREMENTS: enzyme activities of superoxide dismutase (CuZn-SOD), glutathione peroxidase, catalase and glutathione reductase (GR) in erythrocytes. Functional capacity among the centenarians was evaluated by Katz' index of activities of daily living, the Physical...

Determinants of selenium status in healthy adults

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Hoeg Antonia

2011-07-01

Full Text Available Abstract Background Selenium (Se status in non-deficient subjects is typically assessed by the Se contents of plasma/serum. That pool comprises two functional, specific selenoprotein components and at least one non-functional, non-specific components which respond differently to changes in Se intake. A more informative means of characterizing Se status in non-deficient individuals is needed. Methods Multiple biomarkers of Se status (plasma Se, serum selenoprotein P [SEPP1], plasma glutathione peroxidase activity [GPX3], buccal cell Se, urinary Se were evaluated in relation to selenoprotein genotypes (GPX1, GPX3, SEPP1, SEP15, dietary Se intake, and parameters of single-carbon metabolism in a cohort of healthy, non-Se-deficient men (n = 106 and women (n = 155. Conclusions Plasma Se concentration was 142.0 ± 23.5 ng/ml, with GPX3 and serum-derived SEPP1 calculated to comprise 20% and 34%, respectively, of that total. The balance, comprised of non-specific components, accounted for virtually all of the interindividual variation in total plasma Se. Buccal cell Se was associated with age and plasma homocysteine (hCys, but not plasma Se. SEPP1 showed a quadratic relationship with body mass index, peaking at BMI 25-30. Urinary Se was greater in women than men, and was associated with metabolic body weight (kg0.75, plasma folate, vitamin B12 and hCys (negatively. One GPX1 genotype (679T/T was associated with significantly lower plasma Se levels than other allelic variants. Selenium intake, estimated from food frequency questionnaires, did not predict Se status as indicated by any biomarker. These results show that genotype, methyl-group status and BMI contribute to variation in Se biomarkers in Se-adequate individuals.

Overexpression of cellular glutathione peroxidase rescues homocyst(e)ine-induced endothelial dysfunction

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Weiss, Norbert; Zhang, Ying-Yi; Heydrick, Stanley; Bierl, Charlene; Loscalzo, Joseph

2001-01-01

Homocyst(e)ine (Hcy) inhibits the expression of the antioxidant enzyme cellular glutathione peroxidase (GPx-1) in vitro and in vivo, which can lead to an increase in reactive oxygen species that inactivate NO and promote endothelial dysfunction. In this study, we tested the hypothesis that overexpression of GPx-1 can restore the normal endothelial phenotype in hyperhomocyst(e)inemic states. Heterozygous cystathionine β-synthase-deficient (CBS(−/+)) mice and their wild-type littermates (CBS(+/+)) were crossbred with mice that overexpress GPx-1 [GPx-1(tg+) mice]. GPx-1 activity was 28% lower in CBS(−/+)/GPx-1(tg−) compared with CBS(+/+)/GPx-1(tg−) mice (P < 0.05), and CBS(−/+) and CBS(+/+) mice overexpressing GPx-1 had 1.5-fold higher GPx-1 activity compared with GPx-1 nontransgenic mice (P < 0.05). Mesenteric arterioles of CBS(−/+)/GPx-1(tg−) mice showed vasoconstriction to superfusion with β-methacholine and bradykinin (P < 0.001 vs. all other groups), whereas nonhyperhomocyst(e)inemic mice [CBS(+/+)/GPx-1(tg−) and CBS(+/+)/GPx-1(tg+) mice] demonstrated dose-dependent vasodilation in response to both agonists. Overexpression of GPx-1 in hyperhomocyst(e)inemic mice restored the normal endothelium-dependent vasodilator response. Bovine aortic endothelial cells (BAEC) were transiently transfected with GPx-1 and incubated with dl-homocysteine (HcyH) or l-cysteine. HcyH incubation decreased GPx-1 activity in sham-transfected BAEC (P < 0.005) but not in GPx-1-transfected cells. Nitric oxide release from BAEC was significantly decreased by HcyH but not cysteine, and GPx-1 overexpression attenuated this decrease. These findings demonstrate that overexpression of GPx-1 can compensate for the adverse effects of Hcy on endothelial function and suggest that the adverse vascular effects of Hcy are at least partly mediated by oxidative inactivation of NO. PMID:11606774

Glutathione peroxidase mimic ebselen improves glucose-stimulated insulin secretion in murine islets.

Science.gov (United States)

Wang, Xinhui; Yun, Jun-Won; Lei, Xin Gen

2014-01-10

Glutathione peroxidase (GPX) mimic ebselen and superoxide dismutase (SOD) mimic copper diisopropylsalicylate (CuDIPs) were used to rescue impaired glucose-stimulated insulin secretion (GSIS) in islets of GPX1 and(or) SOD1-knockout mice. Ebselen improved GSIS in islets of all four tested genotypes. The rescue in the GPX1 knockout resulted from a coordinated transcriptional regulation of four key GSIS regulators and was mediated by the peroxisome proliferator-activated receptor gamma coactivator 1 alpha (PGC-1α)-mediated signaling pathways. In contrast, CuDIPs improved GSIS only in the SOD1 knockout and suppressed gene expression of the PGC-1α pathway. Islets from the GPX1 and(or) SOD1 knockout mice provided metabolically controlled intracellular hydrogen peroxide (H2O2) and superoxide conditions for the present study to avoid confounding effects. Bioinformatics analyses of gene promoters and expression profiles guided the search for upstream signaling pathways to link the ebselen-initiated H2O2 scavenging to downstream key events of GSIS. The RNA interference was applied to prove PGC-1α as the main mediator for that link. Our study revealed a novel metabolic use and clinical potential of ebselen in rescuing GSIS in the GPX1-deficient islets and mice, along with distinct differences between the GPX and SOD mimics in this regard. These findings highlight the necessities and opportunities of discretional applications of various antioxidant enzyme mimics in treating insulin secretion disorders. REBOUND TRACK: This work was rejected during standard peer review and rescued by Rebound Peer Review (Antioxid Redox Signal 16: 293-296, 2012) with the following serving as open reviewers: Regina Brigelius-Flohe, Vadim Gladyshev, Dexing Hou, and Holger Steinbrenner.

Relationship between glutation peroxidase (GSH-PX) activity and the uptake of 75-Se by erytrocytes for practical assesment of selenium status in dairy cows

International Nuclear Information System (INIS)

Danius, J.

1988-01-01

An experiment to study the relationship between glutation peroxidase (GSH-Px) activity and the uptake of 75-Se by erytrocytes was conducted for practical assesment of selenium status in Holstein-Friesian (HF) dairy cows. The blood used in the experiment was stored in refrigerator for 7 and 10 days. Radioselenium with a specific activity at about 0.84 mCi/m was used. A high negative correlatin (r = -0.86 and r = -0.98) was found between red blood cell GSH-Px activity and red blood cell uptake of 75-Se. Results indicated that red blood cell uptake of 75-Se can be used for determination of Se status in dairy cattle, although some factors which might affect red blood cell uptake of 75-Se should be calculated first. (author). 21 refs, 2 figs

Altered selenium status in Huntington's disease: neuroprotection by selenite in the N171-82Q mouse model.

Science.gov (United States)

Lu, Zhen; Marks, Eileen; Chen, Jianfang; Moline, Jenna; Barrows, Lorraine; Raisbeck, Merl; Volitakis, Irene; Cherny, Robert A; Chopra, Vanita; Bush, Ashley I; Hersch, Steven; Fox, Jonathan H

2014-11-01

Disruption of redox homeostasis is a prominent feature in the pathogenesis of Huntington's disease (HD). Selenium an essential element nutrient that modulates redox pathways and has been reported to provide protection against both acute neurotoxicity (e.g. methamphetamine) and chronic neurodegeneration (e.g. tauopathy) in mice. The objective of our study was to investigate the effect of sodium selenite, an inorganic form of selenium, on behavioral, brain degeneration and biochemical outcomes in the N171-82Q Huntington's disease mouse model. HD mice, which were supplemented with sodium selenite from 6 to 14 weeks of age, demonstrated increased motor endurance, decreased loss of brain weight, decreased mutant huntingtin aggregate burden and decreased brain oxidized glutathione levels. Biochemical studies revealed that selenite treatment reverted HD-associated changes in liver selenium and plasma glutathione in N171-82Q mice and had effects on brain selenoprotein transcript expression. Further, we found decreased brain selenium content in human autopsy brain. Taken together, we demonstrate a decreased selenium phenotype in human and mouse HD and additionally show some protective effects of selenite in N171-82Q HD mice. Modification of selenium metabolism results in beneficial effects in mouse HD and thus may represent a therapeutic strategy. Copyright © 2014 Elsevier Inc. All rights reserved.

Effect of supplementation with methionine and different fat sources on the glutathione redox system of growing chickens.

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Németh, Katalin; Mézes, M; Gaál, T; Bartos, A; Balogh, K; Husvéth, F

2004-01-01

The effect of supplementary methionine and fats of different saturation levels on the glutathione redox system of growing broiler cockerels was studied. The diet of three groups of chicks was supplemented with corn germ oil, beef tallow and fish oil at the levels of 30 g/kg and 50 g/kg of feed, respectively. The diet of further three groups was supplemented with methionine (5 g/kg of feed) in addition to the different fat sources. Control chicks were fed with a compound feed without methionine and fat supplementation. Reduced glutathione (GSH) and glutathione disulphide (GSSG) content as well as glutathione peroxidase activity in the liver were determined and GSH/GSSG ratio was calculated at day old and then at one and three weeks of age. Our results indicate that supplementary methionine stimulates both the synthesis of the glutathione redox system and glutathione peroxidase activity in growing chickens in the first period of postnatal life, when the risk of lipid peroxidation is high due to feeding unsaturated fats in the diet.

Protection of myocytes against free radical-induced damage by accelerated turnover of the glutathione redox cycle

NARCIS (Netherlands)

Le, C. T.; Hollaar, L.; van der Valk, E. J.; Franken, N. A.; van Ravels, F. J.; Wondergem, J.; van der Laarse, A.

1995-01-01

The primary defence mechanism of myocytes against peroxides and peroxide-derived peroxyl and alkoxyl radicals is the glutathione redox cycle. The purpose of the present study was to increase the turnover rate of this cycle by stimulating the glutathione peroxidase catalysed reaction (2GSH-->GSSG),

Selenium, selenoenzymes, oxidative stress and risk of neoplastic progression from Barrett's esophagus: results from biomarkers and genetic variants.

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Yumie Takata

Full Text Available Clinical trials have suggested a protective effect of selenium supplementation on the risk of esophageal cancer, which may be mediated through the antioxidant activity of selenoenzymes. We investigated whether serum selenium concentrations, selenoenzyme activity, oxidative stress and genetic variation in selenoenzymes were associated with the risk of neoplastic progression to esophageal adenocarcinoma (EA and two intermediate endpoints, aneuploidy and tetraploidy. In this prospective cohort study, during an average follow-up of 7.3 years, 47 EA cases, 41 aneuploidy cases and 51 tetraploidy cases accrued among 361 participants from the Seattle Barrett's Esophagus Research Study who were free of EA at the time of blood draw and had at least one follow-up visit. Development to EA was assessed histologically and aneuploidy and tetraploidy by DNA content flow cytometry. Serum selenium concentrations were measured using atomic absorption spectrometry, activity of glutathione peroxidase (GPX 1 and GPX3 by substrate-specific coupled test procedures, selenoprotein P (SEPP1 concentrations and protein carbonyl content by ELISA method and malondialdehyde concentrations by HPLC. Genetic variants in GPX1-4 and SEPP1 were genotyped. Serum selenium was not associated with the risk of neoplastic progression to EA, aneuploidy or tetraploidy (P for trend = 0.25 to 0.85. SEPP1 concentrations were positively associated with the risk of EA [hazard ratio (HR = 3.95, 95% confidence intervals (CI = 1.42-10.97 comparing the third tertile with the first] and with aneuploidy (HR = 6.53, 95% CI = 1.31-32.58, but not selenoenzyme activity or oxidative stress markers. No genetic variants, overall, were associated with the risk of neoplastic progression to EA (global p = 0.12-0.69. Our results do not support a protective effect of selenium on risk of neoplastic progression to EA. Our study is the first to report positive associations of plasma SEPP1

Selenium-containing enzymes in mammals: Chemical perspectives

Indian Academy of Sciences (India)

The role of selenocysteine moiety in natural mammalian enzymes such as glutathione peroxidase (GPx), iodothyronine deiodinase (ID) and thioredoxin reductase (TrxR) is highlighted and the effect of other amino acid residues located in close proximity to selenocysteine is described. It is evident from various studies that ...

Clinical Assessment of glutathione peroxidase and catalase to the status of malondialdehyde in urolithiasis

International Nuclear Information System (INIS)

Mahmoud, R.H.; Ewadh, M.J.; Al-Hamadani, K.J.

2010-01-01

Objective: To assess the role of lipid peroxidation and antioxidant enzymes in serum of urolithiasis patients. Methodology: Glutathione peroxidase (GPx), catalase (CAT) and malondialadehyde (MDA) in serum of urolithiasis patients have been measured. Results: The study has revealed a significant increase in MDA and a significant decrease in GPx and CAT. There have been no significant correlations of serum MDA, GPx and CAT to the size and number of stones with no differences in their levels among patients with one stone, two stones and multiple stones. Anatomically the distributions of urinary stones have been 70.14% renal, 19.30% ureteric and 3.15% urinary bladder. There have been no significant difference in serum levels of neither MDA nor CAT among all the anatomical sites of the stone, while GPx has shown a significant difference in serum of patients with renal calyceal, renal pelvic, ureteric and vesical stones. Patients with recurrent episode of urinary stone have been 63.33%. Family histories of urolithiasis have been negative in 73.33% of the patients. Neither recurrence of urinary stone nor family history of urolithiasis have shown a significant correlation with serum levels of MDA, GPx and CAT. Conclusion: The role of lipid peroxidation and antioxidant enzymes is present in the pathogenesis of urinary stone, but their levels don't affect by the size, the number and the anatomical position of stones (apart of GPx which has been affected by the anatomical position of the stone) and the duration, recurrence, and family history of the disease. (author)

Antioxidant and hepatoprotective role of selenium against silver nanoparticles

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Ansar S

2017-10-01

Full Text Available Sabah Ansar,1 Saad M Alshehri,2 Manal Abudawood,1 Sherifa S Hamed,3,4 Tansir Ahamad2 1Clinical Laboratory Sciences, Applied Medical Science, King Saud University, Riyadh, Saudi Arabia; 2Department of Chemistry, College of Science, King Saud University, Riyadh, Saudi Arabia; 3Zoology Department, College of Science, King Saud University, Riyadh, Saudi Arabia; 4Zoology Department, Faculty of Science, University of Alexandria, Moharram Bey, Alexandria, Egypt Abstract: Silver nanoparticles (AgNPs have attracted the most interest in terms of their potential biomedical and industrial applications. However, these nanoparticles have shown their toxic behavior toward environment, living tissues, and organisms. Selenium (Se, an essential trace element, is necessary for various metabolic processes, including protection against ­oxidative stress and immune function. The present study was undertaken to evaluate the effect of Se against AgNP-induced hepatic oxidative stress. AgNPs were synthesized and then prepared nanoparticles were characterized using various analytical techniques such as UV-visible spectroscopy, X-ray diffraction, and transmission electron microscopy. Rats were administered AgNPs intraperitoneally (5 mg/kg/day and Se (0.2 mg/kg was given by gavage. AgNP administration induced hepatic damage as indicated by the serum marker enzymes with reduction in levels of glutathione, and decrease in activities of SOD, CAT, and GSH-peroxidase (P<0.05. Decrease in levels of total antioxidant capacity (TAC and increase in level of C-reactive protein (CRP was also observed in AgNP-treated group compared to control group. However, Se markedly attenuated AgNP-induced biochemical alterations, levels of TAC, CRP, and serum transaminases (AST, ALT (P<0.05. Taken together, these findings suggest that administration of AgNPs produces hepatotoxicity in rats, whereas Se supplementation attenuates these effects. Keywords: silver nanoparticles, selenium, antioxidant

Molecular characterization and functional analysis of a glutathione peroxidase gene from Aphelenchoides besseyi (Nematoda: Aphelenchoididae).

Science.gov (United States)

Wang, Bu-Yong; Wen, Rong-Rong; Ma, Ling

2017-09-26

Aphelenchoides besseyi, the nematode agent of rice tip white disease, causes huge economic losses in almost all the rice-growing regions of the world. Glutathione peroxidase (GPx), an esophageal glands secretion protein, plays important roles in the parasitism, immune evasion, reproduction and pathogenesis of many plant-parasitic nematodes (PPNs). Therefore, GPx is a promising target for control A. besseyi. Here, the full-length sequence of the GPx gene from A. besseyi (AbGPx1) was cloned using the rapid amplification of cDNA ends method. The full-length 944 bp AbGPx1 sequence, which contains a 678 bp open reading frame, encodes a 225 amino acid protein. The deduced amino acid sequence of the AbGPxl shares highly homologous with other nematode GPxs, and showed the closest evolutionary relationship with DrGPx. In situ hybridization showed that AbGPx1 was constitutively expressed in the esophageal glands of A. besseyi, suggesting its potential roles in parasitism and reproduction. RNA interference (RNAi) was used to assess the functions of the AbGPx1 gene, and quantitative real-time PCR was used to monitor the RNAi effects. After treatment with dsRNA for 12 h, AbGPx1 expression levels and reproduction in the nematodes decreased compared with the same parameters in the control group; thus, the AbGPx1 gene is likely to be associated with the development, reproduction, and infection ability of A. besseyi. These findings may open new avenues towards nematode control.

The importance of Arabidopsis glutathione peroxidase 8 for protecting Arabidopsis plant and E. coli cells against oxidative stress.

Science.gov (United States)

Gaber, Ahmed

2014-01-01

Glutathione peroxidases (GPXs) are major family of the reactive oxygen species (ROS) scavenging enzymes. Recently, database analysis of the Arabidopsis genome revealed a new open-reading frame, thus increasing the total number of AtGPX gene family to eight (AtGPX1-8). The effect of plant hormones like; i. e. salicylic acid (SA), jasmonic acid (JA), abscisic acid (ABA), indoleacetic acid (IAA), and mannitol on the expression of the genes confirm that the AtGPX genes family is regulated by multiple signaling pathways. The survival rate of AtGPX8 knockout plants (KO8) was significantly decreased under heat stress compared with the wild type. Moreover, the content of malondialdehyde (MDA) and protein oxidation was significantly increased in the KO8 plant cells under heat stress. Results indicating that the deficiency of AtGPX8 accelerates the progression of oxidative stress in KO8 plants. On the other hand, the overexpression of AtGPX8 in E. coli cells enhance the growth of the recombinant enzyme on media supplemented with 0.2 mM cumene hydroperoxide, 0.3 mM H 2O 2 or 600 mM NaCl.

The influence of heroin abuse on glutathione-dependent enzymes in human brain.

Science.gov (United States)

Gutowicz, Marzena; Kaźmierczak, Beata; Barańczyk-Kuźma, Anna

2011-01-01

Heroin is an illicit narcotic abused by millions of people worldwide. In our earlier studies we have shown that heroin intoxication changes the antioxidant status in human brain. In the present work we continued our studies by estimating the effect of heroin abuse on reduced glutathione (GSH) and enzymes related to this cofactor, such as glutathione S-transferase detoxifying electrophilics (GST) and organic peroxides (as Se-independent glutathione peroxidase-GSHPx), and Se-dependent glutathione peroxidase (Se-GSHPx) specific mainly for hydrogen peroxide. Studies were conducted on human brains obtained from autopsy of 9 heroin abusers and 8 controls. The level of GSH and the activity of glutathione-related enzymes were determined spectrophotometrically. The expression of GST pi on mRNA and protein level was studied by RT-PCR and Western blotting, respectively. The results indicated significant increase of GST and GSHPx activities, unchanged Se-GSHPx activity, and decreased level of GSH in frontal, temporal, parietal and occipital cortex, brain stem, hippocampus, and white matter of heroin abusers. GST pi expression was increased on both mRNA and protein levels, however the increase was lower in brain stem than in other regions. Heroin affects all regions of human brain, and especially brain stem. Its intoxication leads to an increase of organic rather then inorganic peroxides in various brain regions. Glutathione S-transferase plays an important role during heroin intoxication, however its protective effect is lower in brain stem than in brain cortex or hippocampus. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

Oxidation of eugenol by purified human term placental peroxidase.

Science.gov (United States)

Zhang, R; Kulkarni, K A; Kulkarni, A P

2000-01-01

The oxidation of eugenol by purified human term placental peroxidase (HTPP) was examined. Spectral analyses indicated that, similar to horseradish peroxidase, HTPP is capable of catalyzing the oxidation of eugenol. The accumulated stable product in the reaction medium due to eugenol oxidation by HTPP was tentatively identified as quinone methide of eugenol (EQM). The EQM formation exhibited a pH optimum of 8.0 and was dependent on incubation time, amount of HTPP and the concentration of both eugenol and hydrogen peroxide. The specific activity of approx 2.8 micromoles of EQM/min/mg protein was observed with different preparations of HTPP. The EQM formation was significantly suppressed by glutathione and ascorbic acid. The classical peroxidase inhibitors viz. potassium cyanide and sodium azide blocked the reaction in a concentration manner. Collectively, the results suggest that eugenol may undergo peroxidative metabolism in human placenta. Copyright 2000 Harcourt Publishers Ltd.

OXIDATIVE MODIFICATION OF PROTEINS AND GLUTATHIONE SYSTEM IN ADIPOCYTES UNDER DIABETES

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Ye. V. Shakhristova

2014-01-01

Full Text Available Currently, diabetes ranks third in relation to medical and social significance after cardiovascular diseases and cancer and is the leading cause of blindness; it greatly increases the risk of myocardial infarction, coronary heart disease, nephropathy and hypertension in patients with this disorder; therefore clinical and experimental studies aimed at investigation of diabetes emergence and development mechanisms are urgent.The aim of the study was to investigate the status of oxidative modification of proteins and glutathionedependent antioxidant defense system in adipocytes of rats with alloxan diabetes under conditions of oxidative stress.Material and methods. Development of type 1 diabetes was induced in rats by alloxan administration (90 mg/kg of body mass. Adipocytes were obtained from epididymal adipose tissue of rats. The level of carbonyl derivatives of proteins, oxidized tryptophan, bityrosine, general, reduced, oxygenated and protein-bound glutathione, as well as glutathione peroxidase activity in adipocytes of rats was determined.Results. In adipocytes of rats with alloxan diabetes, concentration of carbonyl derivatives of proteins, bityrosine and oxidized tryptophan increased on the background of redox-potential of glutathione system and glutathione peroxidase activity decrease.Conclusion. The obtained data indicate the activation of free-radical oxidation of proteins and reduction of antioxidant defense under conditions of oxidative stress in the adipose tissue of rats with alloxan diabetes; this process plays an important role in pathogenesis of diabetes and its complications development.

Silencing of glutathione peroxidase 3 through DNA hypermethylation is associated with lymph node metastasis in gastric carcinomas.

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Dun-Fa Peng

Full Text Available Gastric cancer remains the second leading cause of cancer-related death in the world. H. pylori infection, a major risk factor for gastric cancer, generates high levels of reactive oxygen species (ROS. Glutathione peroxidase 3 (GPX3, a plasma GPX member and a major scavenger of ROS, catalyzes the reduction of hydrogen peroxide and lipid peroxides by reduced glutathione. To study the expression and gene regulation of GPX3, we examined GPX3 gene expression in 9 gastric cancer cell lines, 108 primary gastric cancer samples and 45 normal gastric mucosa adjacent to cancers using quantitative real-time RT-PCR. Downregulation or silencing of GPX3 was detected in 8 of 9 cancer cell lines, 83% (90/108 gastric cancers samples, as compared to non-tumor adjacent normal gastric samples (P<0.0001. Examination of GPX3 promoter demonstrated DNA hypermethylation (≥ 10% methylation level determined by Bisulfite Pyrosequencing in 6 of 9 cancer cell lines and 60% of gastric cancer samples (P = 0.007. We also detected a significant loss of DNA copy number of GPX3 in gastric cancers (P<0.001. Treatment of SNU1 and MKN28 cells with 5-Aza-2' Deoxycytidine restored the GPX3 gene expression with a significant demethylation of GPX3 promoter. The downregulation of GPX3 expression and GPX3 promoter hypermethylation were significantly associated with gastric cancer lymph node metastasis (P = 0.018 and P = 0.029, respectively. We also observed downregulation, DNA copy number losses, and promoter hypermethylation of GPX3 in approximately one-third of tumor-adjacent normal gastric tissue samples, suggesting the presence of a field defect in areas near tumor samples. Reconstitution of GPX3 in AGS cells reduced the capacity of cell migration, as measured by scratch wound healing assay. Taken together, the dysfunction of GPX3 in gastric cancer is mediated by genetic and epigenetic alterations, suggesting impairment of mechanisms that regulate ROS and its possible involvement in

Blood-based biomarkers of selenium and thyroid status indicate possible adverse biological effects of mercury and polychlorinated biphenyls in Southern Beaufort Sea polar bears.

Science.gov (United States)

Knott, Katrina K; Schenk, Patricia; Beyerlein, Susan; Boyd, Daryle; Ylitalo, Gina M; O'Hara, Todd M

2011-11-01

We examined biomarkers of selenium status (whole blood Se; serum Se; glutathione peroxidase activity) and thyroid status (concentrations and ratios of thyroxine, T4; tri-iodothyronine, T3; albumin) in polar bears to assess variations among cohorts, and relationships to circulating concentrations of contaminants. Concentrations of total mercury (Hg) in whole blood were similar among cohorts (prime aged males and females, older animals, ages≥16 years, and young animals, ages 1-5 years; 48.44±35. 81; p=0.253). Concentrations of sum of seven polychlorinated biphenyls (∑PCB7) in whole blood were greater in females (with and without cubs, 26.44±25.82 ng/g ww) and young (26.81±10.67 ng/g ww) compared to males (8.88±5.76 ng/g ww, p0.08). Thyroid hormones were greater in females (solitary females and females with cubs) compared to males (ppolar bears (ppolar bears were more susceptible to changes in blood-based biomarkers of selenium and thyroid status than males. Further classifications of the physiologic states of polar bears and repeated measures of individuals over time are needed to accurately assess the biological impact of combined toxicant exposures. Copyright © 2011 Elsevier Inc. All rights reserved.

[Appreciation of selenium concentration in blood and tissues of male rat as a result of diet ingredients changes and its supplementation with chosen group B vitamins].

Science.gov (United States)

Friedrich, Mariola; Goluch-Koniuszy, Zuzanna; Dolot, Anna; Pilarczyk, Bogumiła

2011-01-01

The influence of diet ingredients and its supplementation with chosen B group vitamins on concentration of selenium in blood serum and tissues and activity of glutathione peroxidase in blood and liver of male rats was examined in the conducted experiment. The animals, aged 5 months, were divided into three groups and fed ad libitum with granulated mixes. Group I with basic mix containing among other things full grains, Group II with modified mix in which full grains were exchanged for wheat flour and in part with saccharose and Group III with modified mix supplemented in excess with vitamins B1, B2, B6 and PP. The experiment was conducted for six weeks during which the amount of consumed feeding stuff was calculated currently and once a week body mass of the animals was checked. When the experiment was finished the activity of GSH-Px was determined by spectrophotometric method in blood and liver whereas concentration of selenium in blood serum, muscles and in liver by fluorometric method. It was ascertained that the change of diet ingredients and its supplementation with chosen group B vitamins was in favour of lowering the amount of selenium in the examined tissues, and the decrease was not only the result of lower amount of the consumed element, but also of its increased usage, forced by the changes taking place under the influence of diet components and its supplementation.

Optimization of Mycelia Selenium Polysaccharide Extraction from Agrocybe cylindracea SL-02 and Assessment of their Antioxidant and Anti-Ageing Activities

Science.gov (United States)

Che, Gen; Zhou, Meng; Gao, Zheng; Li, Shangshang; Ren, Zhenzhen; Hao, Long; Liu, Yu; Jia, Le

2016-01-01

The aim of the present study was to optimize the purification of mycelia selenium polysaccharides (MSPS) from Agrocybe cylindracea SL-02 and characterize their in vitro antioxidant and in vivo anti-ageing activities. The Box-Behnken experimental design (BBD) was evaluated, which showed that the optimum conditions included an extraction temperature of 94.99°C, a pH of 9 and a precipitation temperature of 12°C, and the predicted yield was 11.036 ± 0.31%. The in vitro antioxidant assay demonstrated that MSPS had potential effects on scavenging and enhanced the reducing power of reactive oxygen species. The in vivo anti-ageing evaluation showed that MSPS significantly reduced the malonaldehyde (MDA) contents and total cholesterol (CHOL) levels, and remarkably improved the activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and total antioxidant capacity (T-AOC) in mice in response to D-galactose-induced ageing. Furthermore, the characteristic analysis of MSPS indicated a selenium content of 1.76 ± 0.10 mg/g at a concentration of 6 μg/mL in liquid media and a monosaccharide composition of rhamnose, arabinose, mannose, glucose and galactose at a molar ratio of 29:3:1:18.8:2.7. These results suggest that MSPS might be suitable for functional foods and natural drugs on preventing the ageing progress induced by toxic chemicals. PMID:27532123

Selenium Supplementation Significantly Reduces Thyroid Autoantibody Levels in Patients with Chronic Autoimmune Thyroiditis

DEFF Research Database (Denmark)

Wichman, Johanna Eva Märta; Winther, Kristian Hillert; Bonnema, Steen Joop

2016-01-01

BACKGROUND: Selenium supplementation may decrease circulating thyroid autoantibodies in patients with chronic autoimmune thyroiditis (AIT), but the available trials are heterogenous. This study expands and critically reappraises the knowledge on this topic. METHODS: A literature search identified...... 3366 records. Controlled trials in adults (≥18 years of age) with AIT, comparing selenium with or without levothyroxine (LT4), versus placebo and/or LT4, were eligible. Assessed outcomes were serum thyroid peroxidase (TPOAb) and thyroglobulin (TgAb) autoantibody levels, and immunomodulatory effects...... and LT4-untreated. Heterogeneity was estimated using I(2), and quality of evidence was assessed per outcome, using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) guidelines. RESULTS: In LT4-treated populations, the selenium group had significantly lower TPOAb levels after...

Role of glutathione in tolerance to arsenite in Salvinia molesta, an aquatic fern

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Adinan Alves da Silva

2017-09-01

Full Text Available ABSTRACT In many plant species, tolerance to toxic metals is highly dependent on glutathione, an essential metabolite for cellular detoxification. We evaluated the responses of glutathione metabolism to arsenite (AsIII in Salvinia molesta, an aquatic fern that has unexplored phytoremediation potential. Plants were exposed to different AsIII concentrations in nutrient solution for 24 h. AsIII caused cell membrane damage to submerged leaves, indicating oxidative stress. There was an increase in the glutathione content and ϒ-glutamylcysteine synthetase enzyme activity in the submerged and floating leaves. The glutathione peroxidase and glutathione sulfotransferase enzymes also showed increased activity in both plant parts, whereas glutathione reductase only showed increased activity in the submerged leaves. These findings suggest an important role for glutathione in the protection of S. molesta against the toxic effects of AsIII, with more effective tolerance responses in the floating leaves.

Efeito da adição de glutationa peroxidase e cisteína ao diluidor de congelação do sêmen equino Effect of glutathione peroxidase and cysteine addition in an equine frozen semen medium

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L.O. Barros

2013-04-01

Full Text Available Foram utilizados ejaculados (n=25 de garanhões para avaliar o efeito de glutationa peroxidase (GPx e cisteína na viabilidade de espermatozoides congelados. O sêmen foi diluído em Botu Crio, com antioxidantes, e foram formados os grupos: G1, Controle; G2, 1U GPx ; G3, 5U GPx; G4, 0,5mM cisteína; G5, 1mM cisteína. Depois foi envasado em palhetas (0,5mL e congelado. Após descongelação, 37°C por 30 segundos, alíquotas foram analisadas quanto à integridade de membrana plasmática (IMP e acrossoma (IAc, potencial de membrana mitocondrial (PMM e cinética, nos tempos zero (T0 e 60 minutos (T60. GPx 5U e cisteína 0,5mM determinaram maior (PEjaculates (n=25 of horses were used to assess the effect of glutathione peroxidase (GPx and cysteine on the viability of frozen sperm cells. Semen was extended at Botu Crio with antioxidants, and divided in groups: G1, control; G2, 1 U GPx; G3, 5U GPx; G4, 0.5mM cysteine and G5, 1mM cysteine, packed in 0.5mL straws, and frozen. After thawing (37° C for 30 seconds samples were analyzed for plasma membrane (IMP and acrosome integrity (IAc, mitochondrial membrane potential (MMP and kinematic, at zero (T0 and 60 minutes after (T60. GPx 5U and cysteine 0.5mM increased (P<0.05 IAc at T0, when compared to T60. Cysteine 1mM resulted in a higher (P<0.05 IAc on T60, than GPx 1 and 5U, and cysteine 0.5mM. The PMM from a stallion on T60 was higher (P<0.05 than those of two stallions. In sperm kinematic, VCL and VAP were higher (P<0.05 at T0 compared to T60 for the control group, and one stallion showed larger (P<0.05 kinematic values than other animals. It is concluded that the addition of glutathione peroxidase at concentrations 1U and 5U, and cysteine, at concentrations of 0.5mM and 1mM, does not interfere with the integrity of cryopreserved equine sperm, but preserves the kinetic parameters VCL and VAP after 60 minutes of incubation. It should be noted also that the stallion has a strong influence on sperm

Distribution of Selenium and Oxidative Stress in Breast Tumor-Bearing Mice

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Pei-Chung Chen

2013-02-01

Full Text Available The present study investigated the effects of breast tumors on the blood and tissue distribution of essential trace mineral selenium (Se, and oxidative stress status of mice. Female 10-week-old BALB/cByJNarl mice were randomly assigned into control (CNL and breast tumor-bearing (TB groups. TB mice were injected subcutaneously into the right hind thigh with 5 × 106 EMT6 mouse mammary tumor cells. After 22 days, we measured Se concentrations, Se-dependent glutathione peroxidase (GPx activities, and malondialdehyde (MDA products (indicator of oxidative stress in plasma, various tissues, and plasma vascular endothelial growth factor (VEGF concentrations. There were no significant differences in body weights and daily intake between both groups. Compared with the CNL group, TB mice have decreases in plasma Se concentrations and GPx activities, as well as higher plasma VEGF and MDA concentrations. Plasma Se concentrations were also negatively correlated with plasma MDA and VEGF concentrations. Furthermore, tissue Se concentrations and GPx activities in TB animals were lower; whereas the MDA concentrations higher in various tissues including liver, kidney, brain, lung, spleen, and thymic tissues. In conclusion, disruption of Se homeostasis critically reflects oxidative stress in target tissues, thus may increase the risk for progression of breast cancer and metastasis.

Overexpression of Endogenous Anti-Oxidants with Selenium Supplementation Protects Trophoblast Cells from Reactive Oxygen Species-Induced Apoptosis in a Bcl-2-Dependent Manner.

Science.gov (United States)

Khera, Alisha; Vanderlelie, Jessica J; Holland, Olivia; Perkins, Anthony V

2017-06-01

The human placenta provides life support for the developing foetus, and a healthy placenta is a prerequisite to a healthy start to life. Placental tissue is subject to oxidative stress which can lead to pathological conditions of pregnancy such as preeclampsia, preterm labour and intrauterine growth restriction. Up-regulation of endogenous anti-oxidants may alleviate placental oxidative stress and provide a therapy for these complications of pregnancy. In this study, selenium supplementation, as inorganic sodium selenite (NaSel) or organic selenomethionine (SeMet), was used to increase the protein production and cellular activity of the important redox active proteins glutathione peroxidase (GPx) and thioredoxin reductase (Thx-Red). Placental trophoblast cell lines, BeWo, JEG-3 and Swan-71, were cultured in various concentrations of NaSel or SeMet for 24 h and cell extracts prepared for western blots and enzyme assays. Rotenone and antimycin were used to stimulate mitochondrial reactive oxygen species (ROS) production and induce apoptosis. Trophoblast cells supplemented with 100 nM NaSel and 500 nM SeMet exhibited significantly enhanced expression and activity of both GPx and Thx-Red. Antimycin and rotenone were found to generate ROS when measured by 2',7'-dichlorofluorescein diacetate (DCFDA) assay, and selenium supplementation was shown to reduce ROS production in a dose-dependent manner. Rotenone, 100 μM treatment for 4 h, caused trophoblast cell apoptosis as evidenced by increased Annexin V binding and decreased expression of Bcl-2. In both assays of apoptosis, selenium supplementation was able to prevent apoptosis, preserve Bcl-2 expression and protect trophoblast cells from mitochondrial oxidative stress. This data suggests that selenoproteins such as GPx and Thx-Red have an important role in protecting trophoblast cells from mitochondrial oxidative stress and that selenium supplementation may be important in treating some placental pathologies.

Effects of acetylcysteine and probucol on contrast medium-induced depression of intrinsic renal glutathione peroxidase activity in diabetic rats.

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Yen, Hsueh-Wei; Lee, Hsiang-Chun; Lai, Wen-Te; Sheu, Sheng-Hsiung

2007-04-01

Antioxidants such as N-acetylcysteine and probucol have been used to protect patients from contrast media-induced nephrotoxicity. The mechanisms underlying these protective effects are not well understood. We hypothesized that acetylcysteine and probucol alter the activity of endogenous antioxidant enzyme activity. Four weeks after induction of diabetes with streptozotocin, diabetic and nondiabetic rats were divided into three groups. Group 1 rats did not receive any antioxidant agents. Group 2 rats were treated with acetylcysteine and group 3 rats with probucol for 1 week before injection of the contrast medium diatrizoate (DTZ). We found that diabetic rats had higher renal glutathione peroxidase (GPx) activity than normal rats. DTZ suppressed renal GPx activity significantly in both group 1 diabetic and normal rats. Interestingly, renal GPx activity in both diabetic and normal rats pretreated with acetylcysteine or probucol was not inhibited by DTZ. Renal superoxide dismutase (SOD) increased significantly in normal rats after DTZ injection, but not in diabetic rats. Finally, acetylcysteine or probucol did not significantly influence renal SOD. These findings suggest that the renal protective effects of acetylcysteine and probucol against contrast-induced oxidative stress and nephrotoxicity may be mediated by altering endogenous GPx activity.

Expression of glutathione peroxidase 2 is associated with not only early hepatocarcinogenesis but also late stage metastasis

International Nuclear Information System (INIS)

Suzuki, Shugo; Pitchakarn, Pornsiri; Ogawa, Kumiko; Naiki-Ito, Aya; Chewonarin, Teera; Punfa, Wanisa; Asamoto, Makoto; Shirai, Tomoyuki; Takahashi, Satoru

2013-01-01

Understanding of mechanisms of cancer progression is very important for reduction of cancer mortality. Of six rat hepatocellular carcinoma (HCC) cell lines, differing in their metastatic potential to the lung after inoculation into the tail vein of nude mice, the most metastatic featured particular overexpression of glutathione peroxidase 2 (GPX2). Therefore, we analyzed the influence of interference in highly metastatic L2 cells by siRNA transfection. Gpx2 siRNA significantly inhibited cell proliferation at 24 and 48 h time points with induction of apoptosis but not cell cycle arrest. High expression of mutated p53 was detected in all HCC cell lines, with reduction in Gpx2 siRNA-transfected cells. Migration and invasion in vitro were also suppressed as compared to control siRNA-transfected cells and secretion of matrix metalloproteinase 9 was reduced. In vivo, the numbers and areas of metastatic nodules per area in the lungs were significantly reduced in the mice inoculated with Gpx2 siRNA-transfected cells as compared to control siRNA-transfected cells. In conclusion, expression of GPX2 is associated with cancer metastasis from rat HCCs both in vitro and in vivo. Together with immunohistochemical findings of elevated expression in rat and also human liver lesions, the results point to important roles in hepatocarcinogenesis

Glutathione and its dependent enzymes' modulatory responses to toxic metals and metalloids in fish--a review.

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Srikanth, K; Pereira, E; Duarte, A C; Ahmad, I

2013-04-01

Toxic metals and metalloid are being rapidly added from multiple pathways to aquatic ecosystem and causing severe threats to inhabiting fauna including fish. Being common in all the type of aquatic ecosystems such as freshwater, marine and brackish water fish are the first to get prone to toxic metals and metalloids. In addition to a number of physiological/biochemical alterations, toxic metals and metalloids cause enhanced generation of varied reactive oxygen species (ROS) ultimately leading to a situation called oxidative stress. However, as an important component of antioxidant defence system in fish, the tripeptide glutathione (GSH) directly or indirectly regulates the scavenging of ROS and their reaction products. Additionally, several other GSH-associated enzymes such as GSH reductase (GR, EC 1.6.4.2), GSH peroxidase (EC 1.11.1.9), and GSH sulfotransferase (glutathione-S-transferase (GST), EC 2.5.1.18) cumulatively protect fish against ROS and their reaction products accrued anomalies under toxic metals and metalloids stress conditions. The current review highlights recent research findings on the modulation of GSH, its redox couple (reduced glutathione/oxidised glutathione), and other GSH-related enzymes (GR, glutathione peroxidase, GST) involved in the detoxification of harmful ROS and their reaction products in toxic metals and metalloids-exposed fish.

Influence the oxidant action of selenium in radiosensitivity induction and cell death in yeast Saccharomyces cerevisiae; Influencia da acao oxidante do selenio na inducao da radiossensibilidade e morte celular na levedura Saccharomyces cerevisiae

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Porto, Barbara Abranches de Araujo

2012-07-01

Ionizing radiations are from both natural sources such as from anthropogenic sources. Recently, radiotherapy has emerged as one of the most common therapies against cancer. Co-60 irradiators (cobalt-60 linear accelerators) are used to treat of malignant tumors routinely in hospitals around the world. Exposure to ionizing radiation can induce changes in cellular macromolecules and affect its functions, because they cause radiolysis of the water molecule generating reactive oxygen species, which can cause damage to virtually all organelles and cell components known as oxidative damage that can culminate in oxidative stress. Oxidative stress is a situation in which the balance between oxidants and antioxidants is broken resulting in excessive production of reactive species, it is not accompanied by the increase in antioxidant capacity, making it impossible to neutralize them. Selenium is a micronutrient considered as antioxidant, antiinflammatory, which could prevent cancer. Selenium in biological system exists as seleno proteins. Nowadays, 25 human seleno proteins have been identified, including glutathione peroxidase, an antioxidant enzyme. Yeasts have the ability to incorporate various metals such as iron, cadmium, zinc and selenium, as well as all biological organisms. The yeast Saccharomyces cerevisiae, unlike mammalian cells is devoid of seleno proteins, being considered as a practical model for studies on the toxicity of selenium, without any interference from the metabolism of seleno proteins. Moreover, yeast cells proliferate through the fermentation, the microbial equivalent of aerobic glycolysis in mammals and the process is also used by tumors. Several reports show that the pro-oxidante effects and induced toxic selenium compounds occur at lower doses and in malignant cells compared with benign cells. Therefore selenium giving a great therapeutic potential in cancer treatment .Our objective was to determine whether selenium is capable to sensitize yeasts

Selenium determination in biological materials by neutron activation analysis - statistical comparison between the use of {sup 77m} Se (t{sub 1/2} 17.45 s) and {sup 75} Se (t{sub 1/2} = 119,8 d); Determinacao de selenio em materiais biologicos por analise por ativacao com neutrons - comparacao estatistica entre o uso do {sup 77m} Se (t{sub 1/2} 17.45s) e {sup 75} Se (t{sub 1/2} = 119,8d)

Energy Technology Data Exchange (ETDEWEB)

Catharino, Marilia G.M.; Vasconcelos, Marina B.A. [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil)

2002-07-01

Selenium is nowadays considered to be an essential trace element in human diet. The most extensively studied biochemical role of this element is related to its participation in the composition of glutathione peroxidase. This enzyme acts as an antioxidant for the free radicals formed in the human body. In the present work, selenium was determined by INAA in reference materials ('Human hair' IAEA-085, 'Human hair' IAEA-086, 'Dogfish Liver' DOLT-1 e 'Dogfish Muscle' DORM-1) and in toenails and vitamin supplement, using the short-lived radioisotope {sup 77m} Se. The usual method, which utilizes long- lived {sup 75} Se, was also employed, in order to make a comparative study. A statistical test was applied for this comparison. It was verified that the average concentrations of selenium, in the reference materials and in the samples analyzed, do not differ statistically at a significance level of 0.05, which indicates the applicability of the short-lived {sup 77m} Se for INAA of the matrixes studied. (author)

Investigation of glutathione peroxidase activity in chicken meat under different experimental conditions Investigação da atividade de glutationa peroxidase em carne de frango submetida a diferentes condições experimentais

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Alexandre José Cichoski

2012-12-01

Full Text Available Due to the fact that previous studies on the enzymatic activity of Glutathione peroxidase (GSH-Px diverge widely in their methodology and results, this study aimed to investigate the influence of different analytical conditions on GSH-Px activity in chicken thighs from broilers that were fed different diets with different sources and concentrations of selenium. GSH-Px activity was evaluated six hours after slaughter and 120 days after frozen storage at -18 ºC. The different analytical conditions included time of pre-incubation (0, 10 and 30 minutes, reaction medium, types of substrate (H2O2 (0.72 mM, 7.2 mM, and 72 mM and Terc-butil hydroperoxide 15 mM, and different buffer concentrations (buffer 1, potassium phosphate 50 mM pH 7.0 + EDTA 1 mM + mercaptoethanol 1 mM, and buffer 2, tris-HCl 50 mM pH 7.6 + EDTA 1 mM + mercapthanol 5 mM. The results show that the highest GSH-Px activity was observed when enzyme and substrate were in contact at 22 ºC without any pre-incubation, and that, when used at concentrations above 0.72 mM, hydrogen peroxide saturated the GSH-Px enzyme and inhibited its activity. The enzyme presented higher affinity to hydrogen peroxide when compared to terc-butil peroxide, and the addition of a buffer containing mercaptoethanol did not increase GSH-Px enzymatic activity. The activity of GSH-Px was not influenced by the source and concentration of selenium in the diet either. The obtained results allowed the determination of the best temperature of contact between the enzyme and substrate (22 ºC, the optimum concentration, and the type of substrate and buffer to be used. This information is extremely useful for future studies on GSH-Px activity in meat due to the divergence and little information found in the literature.Uma vez que estudos anteriores sobre a atividade enzimática da glutationa peroxidase (GSH-Px divergem acerca da metodologia e dos resultados, este estudo teve por objetivo investigar a influência de

Effects of Selenite on Unicellular Green Microalga Chlorella pyrenoidosa: Bioaccumulation of Selenium, Enhancement of Photosynthetic Pigments, and Amino Acid Production.

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Zhong, Yu; Cheng, Jay J

2017-12-20

Microalgae were studied as function bioaccumulators of selenium (Se) for food and feed supplement. To investigate the bioaccumulation of Se and its effects on the unicellular green alga Chlorella pyrenoidosa, the algal growth curve, fluorescence parameters, antioxidant enzyme activity, and fatty acid and amino acid profiles were examined. We found that Se at low concentrations (≤40 mg L -1 ) positively promoted algal growth and inhibited lipid peroxidation and intracellular reactive oxygen species. The antioxidative effect was associated with an increase in the levels of glutathione peroxidase, catalase, linolenic acid, and photosynthetic pigments. Meanwhile, a significant increase in amino acid and organic Se content was also detected in the microalgae. In contrast, we found opposite effects in C. pyrenoidosa exposed to >60 mg L -1 Se. The antioxidation and toxicity appeared to be correlated with the bioaccumulation of excess Se. These results provide a better understanding of the effect of Se on green microalgae, which may help in the development of new technological applications for the production of Se-enriched biomass from microalgae.

Selenium supplementation for Hashimoto's thyroiditis.

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van Zuuren, Esther J; Albusta, Amira Y; Fedorowicz, Zbys; Carter, Ben; Pijl, Hanno

2013-06-06

selenite 200 μg plus titrated LT4 compared with placebo plus titrated LT4 (relative risk (RR) 4.67, 95% confidence interval (CI) 1.61 to 13.50; P = 0.004; 36 participants; number needed to treat (NNT) = 2 (95% CI 2 to 3)).Selenomethionine 200 μg reduced the serum levels of anti-thyroid peroxidase antibodies compared with placebo in two studies (mean difference (MD) -917 U/mL, 95% CI -1056 to -778; P levels of anti-thyroid peroxidase antibodies favoured the selenomethionine arm as well (MD -235 IU/mL, 95% CI -374 to -95; P = 0.001; 88 participants). Although the changes from baseline were statistically significant in these three studies, their clinical relevance is unclear. Serum antibodies were not statistically significantly affected in the study comparing sodium selenite 200 μg plus titrated LT4 with placebo plus titrated LT4 (MD -25, 95% CI -181 to 131; P = 0.75; 36 participants).Adverse events were reported in two studies (1 of 85 and 1 of 88 participants, respectively). Selenium supplementation did not appear to have a statistically significant impact on the incidence of adverse events (RR 2.93, 95% CI 0.12 to 70.00; and RR 2.63, 95% CI 0.11 to 62.95). Results of these four studies show that evidence to support or refute the efficacy of selenium supplementation in people with Hashimoto's thyroiditis is incomplete. The current level of evidence for the efficacy of selenium supplementation in the management of people with Hashimoto's thyroiditis is based on four randomised controlled trials assessed at unclear to high risk of bias; this does not at present allow confident decision making about the use of selenium supplementation for Hashimoto's thyroiditis. This review highlights the need for randomised placebo-controlled trials to evaluate the effects of selenium in people with Hashimoto's thyroiditis and can ultimately provide reliable evidence to help inform clinical decision making.

Nanoparticles as potential clinical therapeutic agents in Alzheimer's disease: focus on selenium nanoparticles.

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Nazıroğlu, Mustafa; Muhamad, Salina; Pecze, Laszlo

2017-07-01

In etiology of Alzheimer's disease (AD), involvement of amyloid β (Aβ) plaque accumulation and oxidative stress in the brain have important roles. Several nanoparticles such as titanium dioxide, silica dioxide, silver and zinc oxide have been experimentally using for treatment of neurological disease. In the last decade, there has been a great interest on combination of antioxidant bioactive compounds such as selenium (Se) and flavonoids with the oxidant nanoparticles in AD. We evaluated the most current data available on the physiological effects of oxidant and antioxidant nanoparticles. Areas covered: Oxidative nanoparticles decreased the activities of reactive oxygen species (ROS) scavenging enzymes such as glutathione peroxidase (GSH-Px), superoxide dismutase (SOD) and catalase in the brain of rats and mice. However, Se-rich nanoparticles in small size (5-15 nm) depleted Aβ formation through decreasing ROS production. Reports on low levels of Se in blood and tissue samples and the low activities of GSH-Px, catalase and SOD enzymes in AD patients and animal models support the proposed crucial role of oxidative stress in the pathogenesis of AD. Expert commentary: In conclusion, present literature suggests that Se-rich nanoparticles appeared to be a potential therapeutic compound for the treatment of AD.

Ablation of the Ferroptosis Inhibitor Glutathione Peroxidase 4 in Neurons Results in Rapid Motor Neuron Degeneration and Paralysis.

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Chen, Liuji; Hambright, William Sealy; Na, Ren; Ran, Qitao

2015-11-20

Glutathione peroxidase 4 (GPX4), an antioxidant defense enzyme active in repairing oxidative damage to lipids, is a key inhibitor of ferroptosis, a non-apoptotic form of cell death involving lipid reactive oxygen species. Here we show that GPX4 is essential for motor neuron health and survival in vivo. Conditional ablation of Gpx4 in neurons of adult mice resulted in rapid onset and progression of paralysis and death. Pathological inspection revealed that the paralyzed mice had a dramatic degeneration of motor neurons in the spinal cord but had no overt neuron degeneration in the cerebral cortex. Consistent with the role of GPX4 as a ferroptosis inhibitor, spinal motor neuron degeneration induced by Gpx4 ablation exhibited features of ferroptosis, including no caspase-3 activation, no TUNEL staining, activation of ERKs, and elevated spinal inflammation. Supplementation with vitamin E, another inhibitor of ferroptosis, delayed the onset of paralysis and death induced by Gpx4 ablation. Also, lipid peroxidation and mitochondrial dysfunction appeared to be involved in ferroptosis of motor neurons induced by Gpx4 ablation. Taken together, the dramatic motor neuron degeneration and paralysis induced by Gpx4 ablation suggest that ferroptosis inhibition by GPX4 is essential for motor neuron health and survival in vivo. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

Glutathione peroxidase 4 overexpression inhibits ROS-induced cell death in diffuse large B-cell lymphoma.

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Kinowaki, Yuko; Kurata, Morito; Ishibashi, Sachiko; Ikeda, Masumi; Tatsuzawa, Anna; Yamamoto, Masahide; Miura, Osamu; Kitagawa, Masanobu; Yamamoto, Kouhei

2018-02-20

Regulation of oxidative stress and redox systems has important roles in carcinogenesis and cancer progression, and for this reason has attracted much attention as a new area of cancer therapeutic targets. Glutathione peroxidase 4 (GPX4), an antioxidant enzyme, has biological important functions such as signaling cell death by suppressing peroxidation of membrane phospholipids. However, few studies exist on the expression and clinical relevance of GPX4 in malignant lymphomas such as diffuse large B-cell lymphoma. In this study, we assessed the expression of GPX4 immunohistochemically. GPX4 was expressed in 35.5% (33/93) cases of diffuse large B-cell lymphoma. The GPX4-positive group had poor overall survival (P = 0.0032) and progression-free survival (P = 0.0004) compared with those of the GPX4-negative group. In a combined analysis of GPX4 and 8-hydroxydeoxyguanosine (8-OHdG), an oxidative stress marker, there was a negative correlation between GPX4 and 8-hydroxydeoxyguanosine (P = 0.0009). The GPX4-positive and 8-hydroxydeoxyguanosine-negative groups had a significantly worse prognosis than the other groups in both overall survival (P = 0.0170) and progression-free survival (P = 0.0005). These results suggest that the overexpression of GPX4 is an independent prognostic predictor in diffuse large B-cell lymphoma. Furthermore, in vitro analysis demonstrated that GPX4-overexpressing cells were resistant to reactive oxygen species-induced cell death (P = 0.0360). Conversely, GPX4-knockdown cells were sensitive to reactive oxygen species-induced cell death (P = 0.0111). From these data, we conclude that GPX4 regulates reactive oxygen species-induced cell death. Our results suggest a novel therapeutic strategy using the mechanism of ferroptosis, as well as a novel prognostic predictor of diffuse large B-cell lymphoma.

The effects of redox controls mediated by glutathione peroxidases on root architecture in Arabidopsis thaliana.

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Passaia, Gisele; Queval, Guillaume; Bai, Juan; Margis-Pinheiro, Marcia; Foyer, Christine H

2014-03-01

Glutathione peroxidases (GPXs) fulfil important functions in oxidative signalling and protect against the adverse effects of excessive oxidation. However, there has been no systematic characterization of the functions of the different GPX isoforms in plants. The roles of the different members of the Arabidopsis thaliana GPX gene (AtGPX) family were therefore investigated using gpx1, gpx2, gpx3, gpx4, gpx6, gpx7, and gpx8 T-DNA insertion mutant lines. The shoot phenotypes were largely similar in all genotypes, with small differences from the wild type observed only in the gpx2, gpx3, gpx7, and gpx8 mutants. In contrast, all the mutants showed altered root phenotypes compared with the wild type. The gpx1, gpx4, gpx6, gpx7, and gpx8 mutants had a significantly greater lateral root density (LRD) than the wild type. Conversely, the gpx2 and gpx3 mutants had significantly lower LRD values than the wild type. Auxin increased the LRD in all genotypes, but the effect of auxin was significantly greater in the gpx1, gpx4, and gpx7 mutants than in the wild type. The application of auxin increased GPX4 and GPX7 transcripts, but not GPX1 mRNAs in the roots of wild-type plants. The synthetic strigolactone GR24 and abscisic acid (ABA) decreased LRD to a similar extent in all genotypes, except gpx6, which showed increased sensitivity to ABA. These data not only demonstrate the importance of redox controls mediated by AtGPXs in the control of root architecture but they also show that the plastid-localized GPX1 and GPX7 isoforms are required for the hormone-mediated control of lateral root development.

Effects of the hepatocarcinogen nafenopin, a peroxisome proliferator, on the activities of rat liver glutathione-requiring enzymes and catalase in comparison to the action of phenobarbital.

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Furukawa, K; Numoto, S; Furuya, K; Furukawa, N T; Williams, G M

1985-10-01

The biochemical effects in the livers of male rats of prolonged administration of the experimental hepatocarcinogen nafenopin, a hypolipidemic agent and peroxisome proliferator, were compared to those of another experimental liver carcinogen, phenobarbital, which acts as a neoplasm promoter. Feeding of nafenopin, 0.03 mmol/kg basal diet for up to 24 weeks increased the numbers of hepatic peroxisomes, increased catalase activity, markedly decreased cytosolic glutathione transferase activities toward two substrates, decreased cytosolic glutathione peroxidase activities toward H2O2 and two organic peroxides, and suppressed the age-related increase in gamma-glutamyl transpeptidase activity. In contrast the livers of rats fed an equimolar concentration of phenobarbital displayed increases in cytosolic glutathione transferase activities and enhancement of gamma-glutamyl transpeptidase activity but no changes in glutathione peroxidase activities. There was also an enhancement of catalase activity without apparent increase in peroxisome number. Enzyme kinetic analyses revealed that the cytosolic glutathione transferase activities toward two halogenonitrobenzene substrates were inhibited in the rats fed nafenopin and displayed elevated Km and decreased Vmax. Kinetic studies of glutathione transferase activities in which nafenopin was mixed with normal rat liver cytosols in the assay system revealed competitive type inhibition toward 1-chloro-2,4-dinitrobenzene and a noncompetitive type of inhibition toward 3,4-dichloronitrobenzene. Likewise activities of glutathione peroxidases toward H2O2 and cumene hydroperoxide were suppressed by in vitro addition. Thus the effects of nafenopin and phenobarbital on liver biochemistry were very different. The inhibition of hepatic biotransformation and scavenger systems by nafenopin is suggested to be relevant to its hepatocarcinogenicity.

Antisense Suppression of 2-Cysteine Peroxiredoxin in Arabidopsis Specifically Enhances the Activities and Expression of Enzymes Associated with Ascorbate Metabolism But Not Glutathione Metabolism1

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Baier, Margarete; Noctor, Graham; Foyer, Christine H.; Dietz, Karl-Josef

2000-01-01

The aim of this study was to characterize the effect of decreased 2-cysteine peroxiredoxin (2-CP) on the leaf anti-oxidative system in Arabidopsis. At three stages of leaf development, two lines of transgenic Arabidopsis mutants with decreased contents of chloroplast 2-CP were compared with wild type and a control line transformed with an empty vector. Glutathione contents and redox state were similar in all plants, and no changes in transcript levels for enzymes involved in glutathione metabolism were observed. Transcript levels for chloroplastic glutathione peroxidase were much lower than those for 2-CP, and both cytosolic and chloroplastic glutathione peroxidase were not increased in the mutants. In contrast, the foliar ascorbate pool was more oxidized in the mutants, although the difference decreased with plant age. The activities of thylakoid and stromal ascorbate peroxidase and particularly monodehydroascorbate reductase were increased as were transcripts for these enzymes. No change in dehydroascorbate reductase activity was observed, and effects on transcript abundance for glutathione reductase, catalase, and superoxide dismutase were slight or absent. The results demonstrate that 2-CP forms an integral part of the anti-oxidant network of chloroplasts and is functionally interconnected with other defense systems. Suppression of 2-CP leads to increased expression of other anti-oxidative genes possibly mediated by increased oxidation state of the leaf ascorbate pool. PMID:11027730

Docosahexaenoic (DHA modulates phospholipid-hydroperoxide glutathione peroxidase (Gpx4 gene expression to ensure self-protection from oxidative damage in hippocampal cells

Directory of Open Access Journals (Sweden)

Veronica eCasañas-Sanchez

2015-07-01

Full Text Available Docosahexaenoic acid (DHA, 22:6n-3 is a unique polyunsaturated fatty acid particularly abundant in nerve cell membrane phospholipids. DHA is a pleiotropic molecule that, not only modulates the physicochemical properties and architecture of neuronal plasma membrane, but it is also involved in multiple facets of neuronal biology, from regulation of synaptic function to neuroprotection and modulation of gene expression. As a highly unsaturated fatty acid due to the presence of six double bonds, DHA is susceptible for oxidation, especially in the highly pro-oxidant environment of brain parenchyma. We have recently reported the ability of DHA to regulate the transcriptional program controlling neuronal antioxidant defenses in a hippocampal cell line, especially the glutathione/glutaredoxin system. Within this antioxidant system, DHA was particularly efficient in triggering the upregulation of Gpx4 gene, which encodes for the nuclear, cytosolic and mitochondrial isoforms of phospholipid-hydroperoxide glutathione peroxidase (PH-GPx/GPx4, the main enzyme protecting cell membranes against lipid peroxidation and capable to reduce oxidized phospholipids in situ. We show here that this novel property of DHA is also significant in the hippocampus of wild-type mice and APP/PS1 transgenic mice, a familial model of Alzheimer’s disease. By doing this, DHA stimulates a mechanism to self-protect from oxidative damage even in the neuronal scenario of high aerobic metabolism and in the presence of elevated levels of transition metals, which inevitably favor the generation of reactive oxygen species. Noticeably, DHA also upregulated a novel Gpx4 splicing variant, harboring part of the first intronic region, which according to the ‘sentinel RNA hypothesis’ would expand the ability of Gpx4 (and DHA to provide neuronal antioxidant defense independently of conventional nuclear splicing in cellular compartments, like dendritic zones, located away from nuclear

Glutathione level after long-term occupational elemental mercury exposure

International Nuclear Information System (INIS)

Kobal, Alfred Bogomir; Prezelj, Marija; Horvat, Milena; Krsnik, Mladen; Gibicar, Darija; Osredkar, Josko

2008-01-01

Many in vitro and in vivo studies have elucidated the interaction of inorganic mercury (Hg) and glutathione. However, human studies are limited. In this study, we investigated the potential effects of remote long-term intermittent occupational elemental Hg vapour (Hg o ) exposure on erythrocyte glutathione levels and some antioxidative enzyme activities in ex-mercury miners in the period after exposure. The study included 49 ex-mercury miners divided into subgroups of 28 still active, Hg o -not-exposed miners and 21 elderly retired miners, and 41 controls, age-matched to the miners subgroup. The control workers were taken from 'mercury-free works'. Reduced glutathione (GSH) and oxidized disulphide glutathione (GSSG) concentrations in haemolysed erythrocytes were determined by capillary electrophoresis, while total glutathione (total GSH) and the GSH/GSSG ratio were calculated from the determined values. Catalase (CAT), glutathione peroxidase (GPx), and glutathione reductase (GR) activities in erythrocytes were measured using commercially available reagent kits, while urine Hg (U-Hg) concentrations were determined by cold vapour atomic absorption (CVAAS). No correlation of present U-Hg levels, GSH, GSSG, and antioxidative enzymes with remote occupational biological exposure indices were found. The mean CAT activity in miners and retired miners was significantly higher (p o could be an inductive and additive response to maintain the balance between GSH and antioxidative enzymes in interaction with the Hg body burden accumulated during remote occupational exposure, which does not represent a severely increased oxidative stress

Correction of glutathione metabolism in the liver of albino rats affected by low radiation doses

International Nuclear Information System (INIS)

Moiseenok, A.G.; Slyshenkov, V.S.; Khomich, T.I.; Zimatkina, T.I.; Kanunnikova, N.P.

1997-01-01

The levels of total glutathione GSH, GSSG and the activities of glutathione reductase and glutathione peroxidase were studied in the liver of adult albino rats subjected to 3-fold external γ-irradiation throughout 2 weeks at the overall dose of 0.75 Gy after 15 h, 2 and 5 days from the last irradiation. Some animals were injected intraperitoneally with the pantothenate containing complex > 3 times on days 1-3 before the irradiation. The radiation related decrease of GSH, GSH/GSSG and the total glutathione level was prevented by the prophylactic administration of the complex and probably at the expense of the activation of the G-SH biosynthesis and/or transport in the liver by the CoA biosynthetic precursor. (author)

Effects of Selenium Supplementation on the Diabetic Condition Depend on the Baseline Selenium Status in KKAy Mice.

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Febiyanto, Novian; Yamazaki, Chiho; Kameo, Satomi; Sari, Dian K; Puspitasari, Irma M; Sunjaya, Deni K; Herawati, Dewi M D; Nugraha, Gaga I; Fukuda, Toshio; Koyama, Hiroshi

2018-01-01

Oxidative stress in obesity leads to insulin resistance in type 2 diabetes. Some selenoproteins possess antioxidant properties, suggesting that selenium (Se) may protect against type 2 diabetes; however, evidence from epidemiological studies is contradictory. We hypothesized that Se status before supplementation (baseline) contributes to the supplementation outcome. This study aimed to clarify the influence of baseline Se status on the effect of Se supplementation on the diabetic condition. Six-week-old KKAy mice were fed a diet without supplemental Se or with 0.1 ppm Se in the form of L-selenomethionine (SeM) for 2 weeks to create low-Se and sufficient-Se baseline statuses, respectively. For the next 4 weeks, low-Se mice were given a SeM (0.5 ppm Se)-supplemented diet, and sufficient-Se mice were given either a SeM (0.5 ppm Se)- or sodium selenite (0.5 ppm Se)-supplemented diet; control groups continued on baseline diets. Serum Se concentrations, glutathione peroxidase (GPx) activities, adiponectin levels, glucose tolerance, and insulin sensitivity were analyzed. All mice became diabetic during the 2-week baseline induction period. At the end of the supplementation period, Se-receiving groups demonstrated significantly higher Se concentrations and GPx activities than their respective controls. Sufficient-Se mice receiving SeM had lower blood glucose levels and better insulin sensitivity than control and sodium selenite-receiving mice, whereas low-Se mice receiving SeM showed no such improvements compared with their controls. Our results suggest that Se supplementation in the form of SeM may help prevent type 2 diabetes aggravation in people taking the 55 μg/day Se recommended dietary allowance.

Synthesis, structure, and glutathione peroxidase-like activity of amino acid containing ebselen analogues and diaryl diselenides.

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Selvakumar, Karuthapandi; Shah, Poonam; Singh, Harkesh B; Butcher, Ray J

2011-11-04

The synthesis of some ebselen analogues and diaryl diselenides, which have amino acid functions as an intramolecularly coordinating group (Se···O) has been achieved by the DCC coupling procedure. The reaction of 2,2'-diselanediylbis(5-tert-butylisophthalic acid) or the activated ester tetrakis(2,5-dioxopyrrolidin-1-yl) 2,2'-diselanediylbis(5-tert-butylisophthalate) with different C-protected amino acids (Gly, L-Phe, L-Ala, and L-Trp) afforded the corresponding ebselen analogues. The used precursor diselenides have been found to undergo facile intramolecular cyclization during the amide bond formation reaction. In contrast, the DCC coupling of 2,2'-diselanediyldibenzoic acid with C-protected amino acids (Gly, L/D-Ala and L-Phe) affords the corresponding amide derivatives and not the ebselen analogues. Some of the representative compounds have been structurally characterized by single-crystal X-ray crystallography. The glutathione peroxidase (GPx)-like activities of the ebselen analogues and the diaryl diselenides have been evaluated by using the coupled reductase assay method. Intramolecularly stabilized ebselen analogues show slightly higher maximal velocity (V(max)) than ebselen. However, they do not show any GPx-like activity at low GSH concentrations at which ebselen and related diselenides are active. This could be attributed to the peroxide-mediated intramolecular cyclization of the corresponding selenenyl sulfide and diaryl diselenide intermediates generated during the catalytic cycle. Interestingly, the diaryl diselenides with alanine (L,L or D,D) amide moieties showed excellent catalytic efficiency (k(cat)/K(M)) with low K(M) values in comparison to the other compounds. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Selenium bioavailability from soy protein isolate and tofu in rats fed a torula yeast-based diet.

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Yan, Lin; Graef, George L; Reeves, Philip G; Johnson, LuAnn K

2009-12-23

Selenium (Se) is an essential nutrient, and soy is a major plant source of dietary protein to humans. The United States produces one-third of the world's soybeans, and the Se-rich Northern Plains produce a large share of the nation's soybeans. The present study used a rat model to determine the bioavailability of Se from a protein isolate and tofu (bean curd) prepared from a soybean cultivar we recently developed specifically for food grade markets. The soybean seeds contained 2.91 mg Se/kg. Male Sprague-Dawley rats were depleted of Se by feeding them a 30% Torula yeast-based diet containing 5 microg Se/kg; after 56 days, they were replenished of Se for an additional 50 days by feeding them the same diet supplemented with 20, 30, or 40 microg Se/kg from soy protein isolate or tofu. l-Selenomethionine (SeMet) was used as a reference. Selenium bioavailability was determined on the basis of the responses of Se-dependent enzyme activities and tissue Se contents, comparing those responses for each soy product to those for SeMet using a slope-ratio method. Dietary supplementation with the protein isolate or tofu resulted in dose-dependent increases in glutathione peroxidase activities in blood and liver and thioredoxin reductase activity in liver, as well as dose-dependent increases in the Se contents of plasma, liver, muscle, and kidneys. These responses indicated an overall bioavailability of approximately 97% for Se from both the protein isolate and tofu, relative to SeMet. These results demonstrate that Se from this soybean cultivar is highly bioavailable in this model and that high-Se soybeans can be good dietary sources of Se.

L-selenomethionine does not protect against testosterone plus 17β-estradiol-induced oxidative stress and preneoplastic lesions in the prostate of NBL rats.

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Özten, Nur; Schlicht, Michael; Diamond, Alan M; Bosland, Maarten C

2014-01-01

Previous animal studies examining dietary selenium effects on prostatic carcinogenesis did not show preventive benefit, including 1 study in a rat model involving testosterone (T) and estradiol (E2)-induced prostatic oxidative stress. Here, we examined modulation of T + E2-induced prostatic oxidative stress, dysplasia, and inflammation by L-selenomethionine at 1.5 or 3.0 mg selenium/kg in NIH-07 diet in Noble (Nbl)/Crl rats treated with T + E2 for 16 wk. Hormone treatment increased immunohistochemical staining for 8-hydroxydeoxyguanosine (8-OHdG) in the prostatic sites of T + E2-induced preneoplasia (P < 0.05), but selenomethionine did not attenuate 8-OHdG staining and dysplasia in the lateral prostate. Glutathione-peroxidase activity (P < 0.05) and mRNA expression were induced by T + E2 (P < 0.0001) but not changed by selenomethionine. Selenomethionine did not cause significant responses in expression and activity of glutathione-peroxidase and MnSOD, except for a reduction of MnSOD protein expression in the lateral prostate (P < 0.01). The absence of reduction of oxidative stress and dysplasia and the minimal effects on antioxidant enzymes caused by selenomethionine are consistent with the null effects observed in selenium supplementation animal studies and clinical trials. Significant (P < 0.01) opposite apoptosis/cell proliferation balance responses to selenomethionine and to T + E2 occurred in the lateral and dorsal prostate, explaining why T + E2 induces lesions selectively in the lateral lobe of NBL rats.

Comparison of pre-treatment and post-treatment use of selenium in retinal ischemia reperfusion injury

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Alper Yazici

2015-04-01

Full Text Available AIM: To investigate the effects of selenium in rat retinal ischemia reperfusion (IR model and compare pre-treatment and post-treatment use. METHODS: Selenium pre-treatment group (n=8 was treated with intraperitoneal (i.p. selenium 0.5 mg/kg for 7d and terminated 24h after the IR injury. Selenium post-treatment group (n=8 was treated with i.p. selenium 0.5 mg/kg for 7d after the IR injury with termination at the end of the 7d period. Sham group (n=8 received i.p. saline injections identical to the selenium volume for 7d with termination 24h after the IR injury. Control group (n=8 received no intervention. Main outcome measures were retina superoxide dismutase (SOD, glutathione (GSH, total antioxidant status (TAS, malondialdehyde (MDA, DNA fragmentation levels, and immunohistological apoptosis evaluation. RESULTS: Compared to the Sham group, selenium pre-treatment had a statistical difference in all parameters except SOD. Post-treatment selenium also resulted in statistical differences in all parameters except the MDA levels. When comparing selenium groups, the pre-treatment selenium group had a statistically higher success in reduction of markers of cell damage such as MDA and DNA fragmentation. In contrast, the post-selenium treatment group had resulted in statistically higher levels of GSH. Histologically both selenium groups succeeded to limit retinal thickening and apoptosis. Pre-treatment use was statistically more successful in decreasing apoptosis in ganglion cell layer compared to post-treatment use. CONCLUSION: Selenium was successful in retinal protection in IR injuries. Pre-treatment efficacy was superior in terms of prevention of tissue damage and apoptosis.

Glutathione Transferase from Trichoderma virens Enhances Cadmium Tolerance without Enhancing Its Accumulation in Transgenic Nicotiana tabacum

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Dixit, Prachy; Mukherjee, Prasun K.; Ramachandran, V.; Eapen, Susan

2011-01-01

Background Cadmium (Cd) is a major heavy metal pollutant which is highly toxic to plants and animals. Vast agricultural areas worldwide are contaminated with Cd. Plants take up Cd and through the food chain it reaches humans and causes toxicity. It is ideal to develop plants tolerant to Cd, without enhanced accumulation in the edible parts for human consumption. Glutathione transferases (GST) are a family of multifunctional enzymes known to have important roles in combating oxidative stresses induced by various heavy metals including Cd. Some GSTs are also known to function as glutathione peroxidases. Overexpression/heterologous expression of GSTs is expected to result in plants tolerant to heavy metals such as Cd. Results Here, we report cloning of a glutathione transferase gene from Trichoderma virens, a biocontrol fungus and introducing it into Nicotiana tabacum plants by Agrobacterium-mediated gene transfer. Transgenic nature of the plants was confirmed by Southern blot hybridization and expression by reverse transcription PCR. Transgene (TvGST) showed single gene Mendelian inheritance. When transgenic plants expressing TvGST gene were exposed to different concentrations of Cd, they were found to be more tolerant compared to wild type plants, with transgenic plants showing lower levels of lipid peroxidation. Levels of different antioxidant enzymes such as glutathione transferase, superoxide dismutase, ascorbate peroxidase, guiacol peroxidase and catalase showed enhanced levels in transgenic plants expressing TvGST compared to control plants, when exposed to Cd. Cadmium accumulation in the plant biomass in transgenic plants were similar or lower than wild-type plants. Conclusion The results of the present study suggest that transgenic tobacco plants expressing a Trichoderma virens GST are more tolerant to Cd, without enhancing its accumulation in the plant biomass. It should be possible to extend the present results to crop plants for developing Cd tolerance and

Glutathione transferase from Trichoderma virens enhances cadmium tolerance without enhancing its accumulation in transgenic Nicotiana tabacum.

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Prachy Dixit

Full Text Available BACKGROUND: Cadmium (Cd is a major heavy metal pollutant which is highly toxic to plants and animals. Vast agricultural areas worldwide are contaminated with Cd. Plants take up Cd and through the food chain it reaches humans and causes toxicity. It is ideal to develop plants tolerant to Cd, without enhanced accumulation in the edible parts for human consumption. Glutathione transferases (GST are a family of multifunctional enzymes known to have important roles in combating oxidative stresses induced by various heavy metals including Cd. Some GSTs are also known to function as glutathione peroxidases. Overexpression/heterologous expression of GSTs is expected to result in plants tolerant to heavy metals such as Cd. RESULTS: Here, we report cloning of a glutathione transferase gene from Trichoderma virens, a biocontrol fungus and introducing it into Nicotiana tabacum plants by Agrobacterium-mediated gene transfer. Transgenic nature of the plants was confirmed by Southern blot hybridization and expression by reverse transcription PCR. Transgene (TvGST showed single gene Mendelian inheritance. When transgenic plants expressing TvGST gene were exposed to different concentrations of Cd, they were found to be more tolerant compared to wild type plants, with transgenic plants showing lower levels of lipid peroxidation. Levels of different antioxidant enzymes such as glutathione transferase, superoxide dismutase, ascorbate peroxidase, guiacol peroxidase and catalase showed enhanced levels in transgenic plants expressing TvGST compared to control plants, when exposed to Cd. Cadmium accumulation in the plant biomass in transgenic plants were similar or lower than wild-type plants. CONCLUSION: The results of the present study suggest that transgenic tobacco plants expressing a Trichoderma virens GST are more tolerant to Cd, without enhancing its accumulation in the plant biomass. It should be possible to extend the present results to crop plants for

Selenium

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Stillings, Lisa L.; Schulz, Klaus J.; DeYoung,, John H.; Seal, Robert R.; Bradley, Dwight C.

2017-12-19

Selenium (Se) was discovered in 1817 in pyrite from copper mines in Sweden. It is a trace element in Earth’s crust, with an abundance of three to seven orders of magnitude less than the major rock-forming elements. Commercial use of selenium began in the United States in 1910, when it was used as a pigment for paints, ceramic glazes, and red glass. Since that time, it has had many other economic uses—notably, in the 1930s and 1940s, when it was used in rectifiers (which change alternating current to direct current), and in the 1960s, when it began to be used in the liner of photocopier drums. In the 21st century, other compounds have replaced selenium in these older products; modern uses for selenium include energy-efficient windows that limit heat transfer and thin-film photovoltaic cells that convert solar energy into electricity.In Earth’s crust, selenium is found as selenide minerals, selenate and selenite salts, and as substitution for sulfur in sulfide minerals. It is the sulfide minerals, most commonly those in porphyry copper deposits, that provide the bulk of the selenium produced for the international commodity market. Selenium is obtained as a byproduct of copper refining and recovered from the anode slimes generated in electrolytic production of copper. Because of this, the countries that have the largest resources and (or) reserves of copper also have the largest resources and (or) reserves of selenium.Because selenium occurs naturally in Earth’s crust, its presence in air, water, and soil results from both geologic reactions and human activity. Selenium is found concentrated naturally in soils that overlie bedrock with high selenium concentrations. Selenium mining, processing, use in industrial and agricultural applications, and disposal may all contribute selenium to the environment. A well-known case of selenium contamination from agricultural practices was discovered in 1983 in the Kesterson National Wildlife Refuge in California. There

The Protective Role of Selenium on Scopolamine-Induced Memory Impairment, Oxidative Stress, and Apoptosis in Aged Rats: The Involvement of TRPM2 and TRPV1 Channels.

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Balaban, Hasan; Nazıroğlu, Mustafa; Demirci, Kadir; Övey, İshak Suat

2017-05-01

Inhibition of Ca 2+ entry into the hippocampus and dorsal root ganglion (DRG) through inhibition of N-methyl-D-aspartate (NMDA) receptor antagonist drugs is the current standard of care in neuronal diseases such as Alzheimer's disease, dementia, and peripheral pain. Oxidative stress activates Ca 2+ -permeable TRPM2 and TRPV1, and recent studies indicate that selenium (Se) is a potent TRPM2 and TRPV1 channel antagonist in the hippocampus and DRG. In this study, we investigated the neuroprotective properties of Se in primary hippocampal and DRG neuron cultures of aged rats when given alone or in combination with scopolamine (SCOP). Thirty-two aged (18-24 months old) rats were divided into four groups. The first and second groups received a placebo and SCOP (1 mg/kg/day), respectively. The third and fourth groups received intraperitoneal Se (1.5 mg/kg/ over day) and SCOP + Se, respectively. The hippocampal and DRG neurons also were stimulated in vitro with a TRPV1 channel agonist (capsaicin) and a TRPM2 channel agonist (cumene hydroperoxide). We found that Se was fully effective in reversing SCOP-induced TRPM2 and TRPV1 current densities as well as errors in working memory and reference memory. In addition, Se completely reduced SCOP-induced oxidative toxicity by modulating lipid peroxidation, reducing glutathione and glutathione peroxidase. The Se and SCOP + Se treatments also decreased poly (ADP-ribose) polymerase activity, intracellular free Ca 2+ concentrations, apoptosis, and caspase 3, caspase 9, and mitochondrial membrane depolarization values in the hippocampus. In conclusion, the current study reports on the cellular level for SCOP and Se on the different endocytotoxic cascades for the first time. Notably, the research indicates that Se can result in remarkable neuroprotective and memory impairment effects in the hippocampal neurons of rats. Graphical abstract Possible molecular pathways of involvement of selenium (Se) in scopolamine (SCOP) induced

The diverse roles of glutathione-associated cell resistance against hypericin photodynamic therapy

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Theodossis A. Theodossiou

2017-08-01

Full Text Available The diverse responses of different cancers to treatments such as photodynamic therapy of cancer (PDT have fueled a growing need for reliable predictive markers for treatment outcome. In the present work we have studied the differential response of two phenotypically and genotypically different breast adenocarcinoma cell lines, MCF7 and MDA-MB-231, to hypericin PDT (HYP-PDT. MDA-MB-231 cells were 70% more sensitive to HYP PDT than MCF7 cells at LD50. MCF7 were found to express a substantially higher level of glutathione peroxidase (GPX4 than MDA-MB-231, while MDA-MB-231 differentially expressed glutathione-S-transferase (GSTP1, mainly used for xenobiotic detoxification. Eighty % reduction of intracellular glutathione (GSH by buthionine sulfoximine (BSO, largely enhanced the sensitivity of the GSTP1 expressing MDA-MB-231 cells to HYP-PDT, but not in MCF7 cells. Further inhibition of the GSH reduction however by carmustine (BCNU resulted in an enhanced sensitivity of MCF7 to HYP-PDT. HYP loading studies suggested that HYP can be a substrate of GSTP for GSH conjugation as BSO enhanced the cellular HYP accumulation by 20% in MDA-MB-231 cells, but not in MCF7 cells. Studies in solutions showed that L-cysteine can bind the GSTP substrate CDNB in the absence of GSTP. This means that the GSTP-lacking MCF7 may use L-cysteine for xenobiotic detoxification, especially during GSH synthesis inhibition, which leads to L-cysteine build-up. This was confirmed by the lowered accumulation of HYP in both cell lines in the presence of BSO and the L-cysteine source NAC. NAC reduced the sensitivity of MCF7, but not MDA-MB-231, cells to HYP PDT which is in accordance with the antioxidant effects of L-cysteine and its potential as a GSTP substrate. As a conclusion we have herein shown that the different GSH based cell defense mechanisms can be utilized as predictive markers for the outcome of PDT and as a guide for selecting optimal combination strategies. Keywords

In silico molecular modeling and docking studies on the leishmanial tryparedoxin peroxidase

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Ozal Mutlu

2014-04-01

Full Text Available Leishmaniasis is one of the most common form of neglected parasitic disease that affects about 350 million people worldwide. Leishmanias have a trypanothione mediated hydroperoxide metabolism to eliminate endogenous or exogenous oxidative agents. Both of 2-Cys peroxiredoxin (Prx and glutathione peroxidase type tryparedoxin peroxidase (Px are the terminal enzymes in the trypanothione dependent detoxification system. Therefore absence of trypanothione redox system in mammals and the sensitivity of trypanosomatids against oxidative stress, enzymes of this pathway are drug targets candidates. In this study, 3D structure of tryparedoxin peroxidase (2-Cys peroxiredoxin type from Leishmania donovani (LdTXNPx was described by homology modeling method based on the template of tryparedoxin peroxidase from Crithidia fasciculata and selected compounds were docked to the active site pocket. The quality of the 3D structure of the model was confirmed by various web based validation programs. When compared secondary and tertiary structure of the model, it showed a typical thioredoxin fold containing a central beta-sheet and three alpha-helices. Docking study showed that the selected compound 2 (CID 16073813 interacted with the active site amino acids and binding energy was -118.675 kcal/mol.

Selenium toxicity but not deficient or super-nutritional selenium status vastly alters the transcriptome in rodents

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Sunde Roger A

2011-01-01

Full Text Available Abstract Background Protein and mRNA levels for several selenoproteins, such as glutathione peroxidase-1 (Gpx1, are down-regulated dramatically by selenium (Se deficiency. These levels in rats increase sigmoidally with increasing dietary Se and reach defined plateaus at the Se requirement, making them sensitive biomarkers for Se deficiency. These levels, however, do not further increase with super-nutritional or toxic Se status, making them ineffective for detection of high Se status. Biomarkers for high Se status are needed as super-nutritional Se intakes are associated with beneficial as well as adverse health outcomes. To characterize Se regulation of the transcriptome, we conducted 3 microarray experiments in weanling mice and rats fed Se-deficient diets supplemented with up to 5 μg Se/g diet. Results There was no effect of Se status on growth of mice fed 0 to 0.2 μg Se/g diet or rats fed 0 to 2 μg Se/g diet, but rats fed 5 μg Se/g diet showed a 23% decrease in growth and elevated plasma alanine aminotransferase activity, indicating Se toxicity. Rats fed 5 μg Se/g diet had significantly altered expression of 1193 liver transcripts, whereas mice or rats fed ≤ 2 μg Se/g diet had Conclusion This study shows that Se toxicity (5 μg Se/g diet in rats vastly alters the liver transcriptome whereas Se-deficiency or high but non-toxic Se intake elicits relatively few changes. This is the first evidence that a vastly expanded number of transcriptional changes itself can be a biomarker of Se toxicity, and that identified transcripts can be used to develop molecular biomarker panels that accurately predict super-nutritional and toxic Se status.

[The activity of glutathione antioxidant system at melaksen and valdoxan action under experimental hyperthyroidism in rats].

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Gorbenko, M V; Popova, T N; Shul'gin, K K; Popov, S S

2013-01-01

Investigation of glutathione antioxidant system activity and diene conjugates content in rats liver and blood serum at the influence of melaksen and valdoxan under experimental hyperthyroidism (EG) has been revealed. It has been established that the activities of glutathione reductase (GR), glutathione peroxidase (GP) and glutathione transferase (GT), growing at pathological conditions, change to the side of control value at these substunces introduction. Reduced glutathione content (GSH) at melaxen and valdoxan action increased compared with values under the pathology, that, obviously, could be associated with a reduction of its spending on the detoxication of free radical oxidation (FRO) toxic products. Diene conjugates level in rats liver and blood serum, increasing at experimental hyperthyroidism conditions, under introduction of melatonin level correcting drugs, also approached to the control meaning. Results of the study indicate on positive effect of melaxen and valdoxan on free radical homeostasis, that appears to be accompanied by decrease of load on the glutathione antioxidant system in comparison with the pathology.

CHANGES IN THE GLUTATHIONE SYSTEM IN P19 EMBRYONAL CARCINOMA CELLS UNDER HYPOXIC CONDITIONS

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D. S. Orlov

2015-01-01

Full Text Available Introduction. According to modern perceptions, tumor growth, along with oxidative stress formation, is accompanied by hypoxia. Nowadays studying the regulation of cellular molecular system functioning by conformational changes in proteins appears to be a topical issue. Research goal was to evaluate the state of the glutathione system and the level of protein glutathionylation in P19 embryonal carcinoma (EC cells under hypoxic conditions.Material and methods. P19 EC cells (mouse embryonal carcinoma cultured under normoxic and hypox-ic conditions served the research material.The concentration of total, oxidized, reduced and protein-bound glutathione, the reduced to oxidized thiol ratio as well as glutathione peroxidase and glutathione reductase activity were determined by spectropho-tometry.Results. Glutathione imbalance was accompanied by a decrease in P19 EC cell redox status under hypox-ic conditions against the backdrop of a rise in protein-bound glutathione.Conclusions. As a result of the conducted study oxidative stress formation was identified when modeling hypoxia in P19 embryonal carcinoma cells. The rise in the concentration of protein-bound glutathione may indicate the role of protein glutathionylation in regulation of P19 cell metabolism and functions un-der hypoxia. 

The effect of excimer laser keratectomy on corneal glutathione-related enzymes in rabbits.

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Bilgihan, Ayşe; Bilgihan, Kamil; Yis, Ozgür; Yis, Nilgün Safak; Hasanreisoglu, Berati

2003-04-01

Glutathione related enzymes are involved in the metabolism and detoxification of cytotoxic and carcinogenic compounds as well as reactive oxygen species. Excimer laser is a very useful tool for the treatment of refractive errors and removing superficial corneal opacities. Previous studies have shown that excimer laser may initiate free radical formation in the cornea. In the present study, we evaluated the effect of excimer laser keratectomy on corneal glutathione-related enzyme activities in rabbits. Animals were divided into five groups, and all groups were compared with the controls (group 1), after epithelial scraping (group 2), transepithelial photorefractive keratectomy (PRK) (group 3), traditional PRK (group 4) and deep traditional PRK (group 5). Corneal glutathione peroxidase (GPx), glutathione S-transferase (GST) and glutathione reductase (GR) activities were measured after 24h. Corneal GPx and GR activities significantly decreased only in group 5 (p < 0.05) but GST activities significantly decreased in all groups when compared with the control group (p < 0.05). In conclusion, excimer laser inhibits the glutathione dependent defense system in the cornea, this effect becomes more prominent after high doses of excimer laser energy and antioxidants may be useful to reduce free radical mediated complications.

The chronic autoimmune thyroiditis quality of life selenium trial (CATALYST)

DEFF Research Database (Denmark)

Winther, Kristian Hillert; Watt, Torquil; Bjørner, Jakob Bue

2014-01-01

Patients with chronic autoimmune thyroiditis have impaired health-related quality of life. The thyroid gland has a high selenium concentration, and specific selenoprotein enzyme families are crucial to immune function, and catalyze thyroid hormone metabolism and redox processes in thyroid cells......-enriched yeast or matching placebo tablets daily for 12 months. The experimental supplement will be SelenoPrecise(R). The primary outcome is thyroid-related quality of life assessed by the Thyroid Patient-Reported Outcome (ThyPRO) questionnaire. Secondary outcomes include serum thyroid peroxidase antibody...

Stability of sonicated aqueous suspensions of phospholipids under air.

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Almog, R; Forward, R; Samsonoff, C

1991-12-01

The stability of phospholipids in liposomal aqueous suspension against oxidative degradation in air was investigated using spectrophotometric indices, glutathione peroxidase reactivity and thin layer chromatography. Zwitterionic phospholipid was found to be susceptible to degradation via oxidation of polyunsaturated hydrocarbon chains and ester hydrolysis, producing oxidized lysophosphatide and free fatty acid derivatives. These products were characterized as hydroperoxides based on their reactivity with the selenium-dependent glutathione peroxidase isolated from human erythrocytes. Lecithin in Tris buffer was more resistant to hydrolysis than in water. The sonication of 8.0 mM of soybean phosphatidylcholine (SB-PC) suspension in 0.1 M Tris (pH 7.5) in the presence of air produced relatively high concentration of conjugated diene hydroperoxide, but a small amount of hydrolyzed products. Anionic phospholipids, such as egg-phosphatidylglycerol (egg-PG), demonstrated higher resistance to air oxidation than the zwitterionic lecithin, but its oxidation was promoted by sonication.

X-ray fluorescence microscopy reveals the role of selenium in spermatogenesis

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Kehr, Sebastian; Malinouski, Mikalai; Finney, Lydia; Vogt, Stefan; Labunskyy, Vyacheslav M.; Kasaikina, Marina V.; Carlson, Bradley A.; Zhou, You; Hatfield, Dolph L.; Gladyshev, Vadim N.

2009-01-01

Selenium (Se) is a trace element with important roles in human health. Several selenoproteins have essential functions in development. However, the cellular and tissue distribution of Se remains largely unknown because of the lack of analytical techniques that image this element with sufficient sensitivity and resolution. Herein, we report that X-ray fluorescence microscopy (XFM) can be used to visualize and quantify the tissue, cellular and subcellular topography of Se. We applied this technique to characterize the role of Se in spermatogenesis and identified a dramatic Se enrichment specifically in late spermatids, a pattern that was not seen in any other elemental maps. This enrichment was due to elevated levels of the mitochondrial form of glutathione peroxidase 4 and was fully dependent on the supplies of Se by Selenoprotein P. High-resolution scans revealed that Se concentrated near the lumen side of elongating spermatids, where structural components of sperm are formed. During spermatogenesis, maximal Se associated with decreased phosphorus, whereas Zn did not change. In sperm, Se was primarily in the midpiece and co-localized with Cu and Fe. XFM allowed quantification of Se in the midpiece (0.8 fg) and head (0.14 fg) of individual sperm cells, revealing the ability of sperm cells to handle the amounts of this element well above its toxic levels. Overall, the use of XFM allowed visualization of tissue and cellular Se and provided important insights in the role of this and other trace elements in spermatogenesis. PMID:19379757

Elevated expression of glutathione peroxidase in PC12 cells results in protection against methamphetamine but not MPTP toxicity.

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Hom, D G; Jiang, D; Hong, E J; Mo, J Q; Andersen, J K

1997-06-01

In vivo administration of either 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) or methamphetamine (MA) produces damage to the dopaminergic nervous system which may be due in part to the generation of reactive oxygen species (ROS). The resistance of superoxide dismutase (SOD) over-expressing transgenic mice to the effects of both MPTP and MA suggests the involvement of superoxide in the resulting neurotoxicity of both compounds. Superoxide can be converted by SOD to hydrogen peroxide, which itself can cause cellular degeneration by reacting with free iron to produce highly reactive hydroxyl radicals resulting in damage to proteins, nucleic acids and membrane phospholipids. Hydrogen peroxide has also been reported to be produced via inhibition of NADH dehydrogenase by MPP + formed during oxidation of MPTP by MAO-B and by dopamine auto-oxidation following MA-induced dopamine release from synaptic vesicles within nerve terminals. To test whether hydrogen peroxide is an important factor in the toxicity of either of these two neurotoxins, we created clonal PC12 lines expressing elevated levels of the hydrogen peroxide-reducing enzyme glutathione peroxidase (GSHPx). Elevation of GSHPx levels in PC12 was found to diminish the rise in ROS levels and lipid peroxidation resulting from MA but not MPTP treatment. Elevated levels of GSHPx also appeared to prevent decreases in transport-mediated dopamine uptake produced via MA administration as well as to attenuate toxin-induced cell loss as measured by either MTT reduction or LDH release. Our data, therefore, suggest that hydrogen peroxide production likely contributes to MA toxicity in dopaminergic neurons.

Effects of intracellular chelatable iron and oxidative stress on transcription of classical cellular glutathione peroxidase gene in murine erythroleukemia cells

International Nuclear Information System (INIS)

Fuchs, O.

1997-01-01

The effect of intracellular chelatable iron levels and of oxidative stress on nuclear classical cellular glutathione peroxidase (GSHPx-1) RNA nascent chain elongation (run-on transcription) and on the stability of cytoplasmic GSHPx-1 mRNA was investigated in murine erythroleukemia (MEL) cells. The amount in the intracellular low molecular mass iron pool was changed by incubation of MEL cells transformed by Friend virus with iron donors or iron chelators. Transcription in vitro in isolated nuclei from treated cells showed that the treatment with chelators (desferrioxamine (DFO), pyridoxal isonicotinoyl hydrazone) decrease the rate of nuclear GSHPx-1 RNA nascent chain elongation in both un-induced and with 5 mmol hexamethylenebisacetamide to erythroid differentiation induced MEL cells. Iron donors (diferric transferrin,, Fe-PIH or their combination) and t-butyl hydroperoxide (t-BuOOH) had the opposite effect on GSHPx-1 gene transcription in run-on experiments. On the other hand, 50 μmol DFO or 2.5 μmol t-BuOOH did not change the stability of cytoplasmic GSHPx-1 mRNA in both un-induced and induced MEL cells treated with 5 μmol actinomycin D and with or without these agents for 9 h. These findings indicate that iron and oxidative stress play their role at the transcriptional level of GSHPx-1 gene expression. (author)

Oxidative status, in vitro iron-induced lipid oxidation and superoxide dismutase, catalase and glutathione peroxidase activities in rhea meat.

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Terevinto, A; Ramos, A; Castroman, G; Cabrera, M C; Saadoun, A

2010-04-01

Rhea (Rhea americana) muscles Obturatorius medialis (OM) Iliotibialis lateralis (IL) and Iliofibularis (I), obtained from farmed animals, were evaluated regarding their oxidative/antioxidant status. The mean level of thiobarbituric acid reactive substances (TBARS) expressed as malonaldehyde (MDA) content was of 0.84 mg MDA/kg wet tissue for the three muscles. TBARS level was significantly higher in IL than OM and I, with the two latter showing similar levels. The mean level of carbonyl proteins expressed as dinitrophenylhydrazine (DNPH) was 1.59 nmol DNPH mg(-1). Carbonyl protein levels were significantly different (POM>I). Iron-induced TBARS generation was not significantly different between the three muscles at any time, nor for each muscle during the 5 h of the experiment. Superoxide dismutase activity in IL muscle was significantly higher (P<0.05) than in I muscle. However, the difference between IL and OM muscles was not significant. The differences between the three muscles became not significant when the results were expressed by mg of protein contained in the extract, instead by g of wet tissue. No differences were found for catalase (micromol of discomposed H(2)O(2) min(-1) g(-1) wet tissue or by mg of protein contained in the extract) and glutathione peroxidase (micromol ol of oxidized NADPH min(-1) g(-1) of wet tissue or by mg of protein contained in the extract) activities between the three muscles. 2009 Elsevier Ltd. All rights reserved.

Glutathione system participation in thoracic aneurysms from patients with Marfan syndrome.

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Zúñiga-Muñoz, Alejandra María; Pérez-Torres, Israel; Guarner-Lans, Verónica; Núñez-Garrido, Elías; Velázquez Espejel, Rodrigo; Huesca-Gómez, Claudia; Gamboa-Ávila, Ricardo; Soto, María Elena

2017-05-01

Aortic dilatation in Marfan syndrome (MFS) is progressive. It is associated with oxidative stress and endothelial dysfunction that contribute to the early acute dissection of the vessel and can result in rupture of the aorta and sudden death. We evaluated the participation of the glutathione (GSH) system, which could be involved in the mechanisms that promote the formation and progression of the aortic aneurysms in MFS patients. Aortic aneurysm tissue was obtained during chest surgery from eight control subjects and 14 MFS patients. Spectrophotometrical determination of activity of glutathione peroxidase (GPx), glutathione-S-transferase (GST), glutathione reductase (GR), lipid peroxidation (LPO) index, carbonylation, total antioxidant capacity (TAC), and concentration of reduced and oxidized glutathione (GSH and GSSG respectively), was performed in the homogenate from aortic aneurysm tissue. LPO index, carbonylation, TGF-β1, and GR activity were increased in MFS patients (p < 0.04), while TAC, GSH/GSSG ratio, GPx, and GST activity were significantly decreased (p < 0.04). The depletion of GSH, in spite of the elevated activity of GR, not only diminished the activity of GSH-depend GST and GPx, but increased LPO, carbonylation and decreased TAC. These changes could promote the structural and functional alterations in the thoracic aorta of MFS patients.

Characterization of Affinity-Purified Isoforms of Acinetobacter calcoaceticus Y1 Glutathione Transferases

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Chin-Soon Chee

2014-01-01

Full Text Available Glutathione transferases (GST were purified from locally isolated bacteria, Acinetobacter calcoaceticus Y1, by glutathione-affinity chromatography and anion exchange, and their substrate specificities were investigated. SDS-polyacrylamide gel electrophoresis revealed that the purified GST resolved into a single band with a molecular weight (MW of 23 kDa. 2-dimensional (2-D gel electrophoresis showed the presence of two isoforms, GST1 (pI 4.5 and GST2 (pI 6.2 with identical MW. GST1 was reactive towards ethacrynic acid, hydrogen peroxide, 1-chloro-2,4-dinitrobenzene, and trans,trans-hepta-2,4-dienal while GST2 was active towards all substrates except hydrogen peroxide. This demonstrated that GST1 possessed peroxidase activity which was absent in GST2. This study also showed that only GST2 was able to conjugate GSH to isoproturon, a herbicide. GST1 and GST2 were suggested to be similar to F0KLY9 (putative glutathione S-transferase and F0KKB0 (glutathione S-transferase III of Acinetobacter calcoaceticus strain PHEA-2, respectively.

Characterization of Affinity-Purified Isoforms of Acinetobacter calcoaceticus Y1 Glutathione Transferases

Science.gov (United States)

Chee, Chin-Soon; Tan, Irene Kit-Ping; Alias, Zazali

2014-01-01

Glutathione transferases (GST) were purified from locally isolated bacteria, Acinetobacter calcoaceticus Y1, by glutathione-affinity chromatography and anion exchange, and their substrate specificities were investigated. SDS-polyacrylamide gel electrophoresis revealed that the purified GST resolved into a single band with a molecular weight (MW) of 23 kDa. 2-dimensional (2-D) gel electrophoresis showed the presence of two isoforms, GST1 (pI 4.5) and GST2 (pI 6.2) with identical MW. GST1 was reactive towards ethacrynic acid, hydrogen peroxide, 1-chloro-2,4-dinitrobenzene, and trans,trans-hepta-2,4-dienal while GST2 was active towards all substrates except hydrogen peroxide. This demonstrated that GST1 possessed peroxidase activity which was absent in GST2. This study also showed that only GST2 was able to conjugate GSH to isoproturon, a herbicide. GST1 and GST2 were suggested to be similar to F0KLY9 (putative glutathione S-transferase) and F0KKB0 (glutathione S-transferase III) of Acinetobacter calcoaceticus strain PHEA-2, respectively. PMID:24892084

Effects of dietary selenium exposure in captive American common eiders

Science.gov (United States)

Franson, J.C.; Hoffman, D.J.; Wells-Berlin, A. M.; Perry, M.C.; Bochsler, V.S.; Finley, D.L.; Flint, Paul L.; Hollmen, T.

2005-01-01

We conducted two studies of Se exposure in captive common eiders (Somateria mollissima). In Study 1, eiders were fed diets with added Se (as L-selenomethionine) in concentrations increasing from 10 ppm to 80 ppm. In Study 2, eiders received control, low exposure (20 ppm Se), and high exposure (60 ppm Se) diets. One duck in the high exposure group in Study 2 died after 36 days. Remaining high exposure ducks in Study 2 and ducks in Study 1 were euthanized after losing 25-30% of their body weight, which occurred after 41 days and 60-78 days, respectively. Body weights did not differ between control and low exposure ducks in Study 2. At the end of Study 1, the mean Se concentration in blood was 32 ppm wet weight (ww). In Study 2, mean blood Se reached 14 ppm ww in the low exposure group and 17 ppm ww in high exposure ducks. Mean Se concentrations in liver were 1252 ppm dry weight (dw) in Study 1, and 351 and 735 ppm dw, respectively, in the low and high exposure groups of Study 2. Oxidative stress was evidenced by Se-associated effects on glutathione metabolism, but not entirely in the same manner as with previous laboratory studies in mallards. In plasma, activities of total and Se-dependent glutathione peroxidase increased with time. As Se concentrations in liver increased, Se-dependent glutathione peroxidase, glutathione reductase, oxidized glutathione, and the ratio of hepatic oxidized to reduced glutathione increased. Total and protein bound sulfhydryl concentrations, reduced glutathione, glutathione-S-transferase, and glucose-6-phosphate dehydrogenase in liver were negatively correlated with Se concentrations in the liver. In Study 2, spleen weights were significantly lower in ducks receiving 60 ppm Se than in those receiving 20 ppm. Gross lesions associated with high Se exposure included emaciation, absence of thymus, loss of nails from digits, and alopecia. Microscopic lesions included severe depletion of lymphoid organs, hepatopathy, and necrosis of feather

GLUTATHIONE AND ANTIOXIDANT ENZYMES IN THE HEPATOPANCREAS OF CRAYFISH PROCAMBARUS CLARKII (GIRARD, 1852 OF LAKE TRASIMENO (ITALY

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ELIA A. C.

2006-01-01

Full Text Available Antioxidant parameters, such as total glutathione, glutathione S-transferase, glutathione peroxidase, glutathione reductase, glyoxalases, catalase, and some heavy metals such as, lead, cadmium and chromium were examined in hepatopancreas of both sexes of Procambarus clarkii collected seasonally from Lake Trasimeno, from winter 2002-2003 to autumn 2003. Heavy metals content in hepatopancreas in males and females of P. clarkii was low and did not vary through the sampling periods and between sexes. On the contrary, crayfish exhibited sex-dependent differences in levels of some enzyme activities and of total glutathione, and no apparent relationship was found between contaminant burdens and antioxidant indexes in hepatopancreas. Because measured metal concentrations were low, other factors, presumably, were involved in antioxidant variations in P. clarkii and these latter seemed to be affected more by biological and environmental factors, other than those related to pollutants body burdens.

Effect of selenium compounds on murine B16 melanoma cells and pigmented cloned pB16 cells

International Nuclear Information System (INIS)

Siwek, B.; Bahbouth, E.; Serra, M.A.; Sabbioni, E.; Pauw-Gillet, M.C. de; Bassleer, R.

1994-01-01

The effects of selenium compounds such as sodium selenite, sodium selenate, seleno-DL-cystine and seleno-DL-methionine (100 μM and 10 μM) on B16 and pigmented cloned pB 16 murine melanoma cells were investigated in vitro. At the tested concentrations, B16 cells showed a greater sensitivity to the toxic effects of sodium selenite and seleno-DL-cystine than pB 16 cells, whereas no decrease of B 16 and pB 16 cell number was observed after incubation with sodium selenate or seleno-DL-methionine. Glutathione (GSH) percentages were strongly decreased only by selenite and seleno-DL-cystine; it was marked more in B 16 than in pB 16 cells. The pretreatment of B 16 cells with a GSH depleting agent (10 μM buthionine-[S,R]-sulfoximine) did not significantly influence the cytotoxic effects of selenite and seleno-DL-cystine. On both cell populations. GSH preincubation (50 μM) enhanced the cytotoxicity of selenite whereas the survival of seleno-DL-cystine treated cells was increased. Glutathione peroxidase (GSH-Px) activity in B 16 cells was more sensitive than in pB 16 cells to the activating effect of selenite, and particularly of seleno-DL-cystine; however, cell-free controls indicated that activation was mainly due to glutathione reductase. The rate of 75 Se (as sodium selenite) uptake in both cell populations was maximal within the first hour of incubation, with a preferential accumulation in the cytosol; after 24 h of incubation, the amount of 75 Se in cytosol and pellet was approximately the same. Gel filtration chromatography of lysed cells after incubation for 6 h with 10 μM 75 Se-selenite showed that the radioactivity was eluted as two peaks corresponding to low (4-9 kDa) and high (280-320 kDa) molecular weights. Possible toxicological mechanisms are discussed at molecular level. (orig./MG)

Nucleotide diversity and gene expression of Catalase and Glutathione peroxidase in irradiated Scots pine (Pinus sylvestris L.) from the Chernobyl exclusion zone

International Nuclear Information System (INIS)

Vornam, Barbara; Arkhipov, Andrey; Finkeldey, Reiner

2012-01-01

In the Chernobyl exclusion zone forest trees have to tolerate and to adapt to ionizing radiation, therefore the molecular basis of their adaptive responses is of the utmost interest. Based on SNP analysis and real time PCR nucleotide diversity and expression profiles of gene fragments of catalase (Cat) and glutathione peroxidase (GPx), which are known as radical scavenging genes, were analysed in the needles of irradiated pine trees of the Chernobyl exclusion zone. In acutely and chronically irradiated trees (50 years old) planted before the accident a higher nucleotide diversity of Cat and more somatic mutations were found compared to their control. Chronically irradiated trees (20 years old) planted after the accident showed a similar nucleotide diversity of Cat compared to their control and in both collectives one somatic mutation was found. The nucleotide diversity of GPx was higher in all analysed trees compared to Cat. No somatic mutation events were found in GPx. For both gene fragments, no association between the received dose in a tree and the nucleotide diversity and mutation events was detected. The expression profiles of Cat and GPx in acutely and chronically and in chronically irradiated trees were similar. Compared to their corresponding control collectives, Cat was up-regulated and GPx slightly down-regulated.

Reactivity of selenium-containing compounds with myeloperoxidase-derived chlorinating oxidants

DEFF Research Database (Denmark)

Carroll, Luke; Pattison, David I.; Fu, Shanlin

2015-01-01

and N-chloramines, causes damage to host tissue. Low molecular mass thiol compounds, including glutathione (GSH) and methionine (Met), have demonstrated efficacy in scavenging MPO-derived oxidants, which prevents oxidative damage in vitro and ex vivo. Selenium species typically have greater reactivity...... compounds (selenomethionine, methylselenocysteine, 1,4-anhydro-4-seleno-L-talitol, 1,5-anhydro-5-selenogulitol) studied. In general, selenomethionine was the most reactive with N-chloramines (k2 0.8-3.4×10(3)M(-1) s(-1)) with 1,5-anhydro-5-selenogulitol and 1,4-anhydro-4-seleno-L-talitol (k2 1.1-6.8×10(2)M......(-1) s(-1)) showing lower reactivity. This resulted in the formation of the respective selenoxides as the primary oxidation products. The selenium compounds demonstrated greater ability to remove protein N-chloramines compared to the analogous sulfur compounds. These reactions may have implications...

Synthesis and biodistribution of 75Se-dinonyl-diselenide

International Nuclear Information System (INIS)

Liu, Y.F.; Qian, H.Q.; Zhang, Q.X.; Wang, X.Y.; Sun, J.G.; Li, B.Z.; Zhang, W.J.

1985-01-01

Selenium-75-labelled dinonyl-diselenide, C 9 H 19 75 SeSeC 9 H 19 , was synthesized and identified. It was injected into white rats in order to observe the selenium distribution in the tissues using inorganic 75 SeO 2 as the control agent. The sequence order of the 75 Se-dinonyl-diselenide uptake by tissues was: pancreas, muscles, stomach, liver, kidneys, spleen, blood, lungs, heart, brain, eyes. A very high accumulation of 75 Se-dinonyl-diselenide in the pancreas was observed, similar to that of the pancreatic imaging agent 75 Se-methionine. Furthermore, the enzymatic activity of glutathione peroxidase in the case of organic diselenide injection was higher than that measured for selenite. Selenium of dinonyl-diselenide was more effective and retainable in the process of converting itself to selenium-containing enzyme via the metabolic reactions. It may be advisable to replace inorganic sodium selenite by organic selenium compounds. Sodium selenite has been widely used in the prevention of the Keshan disease in China. (author)

Resistance, accumulation and transformation of selenium by the cyanobacterium Synechocystis sp. PCC 6803 after exposure to inorganic SeVI or SeIV

International Nuclear Information System (INIS)

Gouget, B.; Avoscan, L.; Collins, R.; Carriere, M.; Sarret, G.

2005-01-01

Our purpose was to investigate the ability of Synechocystis sp. PCC 6803, a photosynthetic prokaryote isolated from fresh water, to resist, incorporate and reduce the oxidized forms of selenium including selenite and selenate, the major selenium species present in aquatic systems. Selenium speciation and the chemical intermediates during selenium transformation were determined by X-ray absorption near edge structure (XANES) spectroscopy. The possible internalisation pathways involving selenium and the metabolic fate of selenate and selenite were examined. Selenate metabolism seemed to proceed via the sulfate reduction pathway resulting in the formation of the R-Se-H, R-Se-R and R-Se-Se-R species. The transformation of selenate to toxic amino acids may explain the high sensitivity of Synechocystis to selenate. Several mechanisms of selenium reduction seem to complete during selenite assimilation. A specific mechanism may transform internalised selenite into selenide and, subsequently induce the biosynthesis of selenoproteins. A non-specific mechanism may interfere with thiols, such as glutathione in the cell cytoplasm, or with proteins in the periplasm of the bacteria, notably thioredoxins. Several hypotheses concerning the complex transformation of selenium in Synechocystis could therefore be proposed. (orig.)

[Effects of melaxen and valdoxan on the activity of glutathione antioxidant system and NADPH-producing enzymes in rat heart under experimental hyperthyroidism conditions].

Science.gov (United States)

Gorbenko, M V; Popova, T N; Shul'gin, K K; Popov, S S

2013-01-01

The effects of melaxen and valdoxan on the activity of glutathione antioxidant system and some NADPH-producing enzymes have been studied under conditions of experimental hyperthyroidism in rat heart. Under the action of these drugs, reduced glutathione (GSH) content increased as compared to values observed under the conditions of pathology. It has been established that the activities of glutathione reductase (GR), glutathione peroxidase (GP), glucose-6-phosphate dehydrogenase, and NADP isocitrate dehydrogenase (increased under pathological conditions) change toward the intact control values upon the introduction of both drugs. The influence of melaxen and valdoxan, capable of producing antioxidant effect, leads apparently to the inhibition of free-radical oxidation processes and, as a consequence, the reduction of mobilization degree of the glutathione antioxidant system.

ENDURANCE TRAINING AND GLUTATHIONE-DEPENDENT ANTIOXIDANT DEFENSE MECHANISM IN HEART OF THE DIABETIC RATS

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Mustafa Atalay

2003-06-01

Full Text Available Regular physical exercise beneficially influences cardiac antioxidant defenses in normal rats. The aim of this study was to test whether endurance training can strengthen glutathione-dependent antioxidant defense mechanism and decrease lipid peroxidation in heart of the streptozotocin-induced diabetic rats. Redox status of glutathione in blood of diabetic rats in response to training and acute exercise was also examined. Eight weeks of treadmill training increased the endurance in streptozotocin-induced diabetic rats. It did not affect glutathione level in heart tissue at rest and also after exercise. On the other hand, endurance training decreased glutathione peroxidase activity in heart, while glutathione reductase and glutathione S-transferase activities were not affected either by acute exhaustive exercise or endurance training. Reduced and oxidized glutathione levels in blood were not affected by either training or acute exercise. Conjugated dienes levels in heart tissue were increased by acute exhaustive exercise and also 8 weeks treadmill training. Longer duration of exhaustion in trained group may have contributed to the increased conjugated dienes levels in heart after acute exercise. Our results suggest that endurance type exercise may make heart more susceptible to oxidative stress. Therefore it may be wise to combine aerobic exercise with insulin treatment to prevent its adverse effects on antioxidant defense in heart in patients with diabetes mellitus

Modulation of the Activities of Catalase, Cu-Zn, Mn Superoxide Dismutase, and Glutathione Peroxidase in Adipocyte from Ovariectomised Female Rats with Metabolic Syndrome

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Rebeca Cambray Guerra

2014-01-01

Full Text Available The aim of this study was to evaluate the association between estrogen removal, antioxidant enzymes, and oxidative stress generated by obesity in a MS female rat model. Thirty two female Wistar rats were divided into 4 groups: Control (C, MS, MS ovariectomized (Ovx, and MS Ovx plus estradiol (E2. MS was induced by administering 30% sucrose to drinking water for 24 weeks. After sacrifice, intra-abdominal fat was dissected; adipocytes were isolated and lipid peroxidation, non-enzymatic antioxidant capacity, and the activities of Cu-Zn and Mn superoxide dismutase (SOD, catalase (CAT, and glutathione peroxidase (GPx were determined. There were no significant differences in the activities of Cu-Zn, Mn SOD, CAT, and GPx between the C and MS groups, but in the MS Ovx group there was a statistically significant decrease in the activities of these enzymes when compared to MS and MS Ovx+E2. The increased lipid peroxidation and nonenzymatic antioxidant capacity found in MS Ovx was significantly decreased when compared to MS and MS Ovx+E2. In conclusion, the removal of E2 by ovariectomy decreases the activity of the antioxidant enzymes in the intra-abdominal tissue of MS female rats; this is reflected by increased lipid peroxidation and decreased nonenzymatic antioxidant capacity.

Changes in glutathione system and lipid peroxidation in rat blood during the first hour after chlorpyrifos exposure

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V. P. Rosalovsky

2015-10-01

Full Text Available Chlorpyrifos (CPF is a highly toxic organophosphate compound, widely used as an active substance of many insecticides. Along with the anticholinesterase action, CPF may affect other biochemical mechanisms, particularly through disrupting pro- and antioxidant balance and inducing free-radical oxidative stress. Origins and occurrence of these phenomena are still not fully understood. The aim of our work was to investigate the effects of chlorpyrifos on key parameters of glutathione system and on lipid peroxidation in rat blood in the time dynamics during one hour after exposure. We found that a single exposure to 50 mg/kg chlorpyrifos caused a linear decrease in butyryl cholinesterase activity, increased activity of glutathione peroxidase and glutathione reductase, alterations in the levels of glutathione, TBA-active products and lipid hydroperoxides during 1 hour after poisoning. The most significant changes in studied parameters were detected at the 15-30th minutes after chlorpyrifos exposure.

Methods of Selenium Supplementation: Bioavailability and Determination of Selenium Compounds.

Science.gov (United States)

Bodnar, Malgorzata; Szczyglowska, Marzena; Konieczka, Piotr; Namiesnik, Jacek

2016-01-01

Selenium, a "dual-surface" element, maintains a very thin line between a level of necessity and harmfulness. Because of this, a deficiency or excess of this element in an organism is dangerous and causes health-related problems, both physically and mentally. The main source of selenium is a balanced diet, with a proper selection of meat and plant products. Meanwhile, the proper assimilation of selenium into these products depends on their bioavailability, bioaccessibility, and/or bioactivity of a given selenium compound. From the time when it was discovered that selenium and its compounds have a significant influence on metabolic processes and in many countries throughout the world, a low quantity of selenium was found in different parts of the environment, pressure was put upon an effective and fast method of supplementing the environment with the help of selenium. This work describes supplementation methods applied with the use of selenium, as well as new ideas for increasing the level of this element in various organisms. Based on the fact that selenium appears in the environment at trace levels, the determination of total amount of selenium or selenium speciation in a given sample demands the selection of appropriate measurement methods. These methods are most often comprised of a sample preparation technique and/or a separation technique as well as a detection system. The work presents information on the subject of analytical methods used for determining selenium and its compounds as well as examples in literature of their application.

Biocompatibility selenium nanoparticles with an intrinsic oxidase-like activity

International Nuclear Information System (INIS)

Guo, Leilei; Huang, Kaixun; Liu, Hongmei

2016-01-01

Selenium nanoparticles (SeNPs) are considered to be the new selenium supplement forms with high biological activity and low toxicity; however, the molecular mechanism by which SeNPs exert the biological function is unclear. Here, we reported that biocompatibility SeNPs possessed intrinsic oxidase-like activity. Using Na 2 SeO 3 as a precursor and glutathione as a reductant, biocompatibility SeNPs were synthesized by the wet chemical reduction method in the presence of bovine serum albumin (BSA). The results of structure characterization revealed that synthesized SeNPs were amorphous red elementary selenium with spherical morphology, and ranged in size from 25 to 70 nm size with a narrow distribution (41.4 ± 6.7 nm). The oxidase-like activity of the as-synthesized SeNPs was tested with 3,3′,5,5′-tetramethylbenzidine (TMB) as a substrate. The results indicated that SeNPs could catalyze the oxidization of TMB by dissolved oxygen. These SeNPs showed an optimum catalytic activity at pH 4 and 30 °C, and the oxidase-like activity was higher as the concentration of SeNPs increased and the size of SeNPs decreased. The Michaelis constant (K m ) values and maximal reaction velocity (V max ) of the SeNPs for TMB oxidation were 0.0083 mol/L and 3.042 μmol/L min, respectively.

Biocompatibility selenium nanoparticles with an intrinsic oxidase-like activity

Science.gov (United States)

Guo, Leilei; Huang, Kaixun; Liu, Hongmei

2016-03-01

Selenium nanoparticles (SeNPs) are considered to be the new selenium supplement forms with high biological activity and low toxicity; however, the molecular mechanism by which SeNPs exert the biological function is unclear. Here, we reported that biocompatibility SeNPs possessed intrinsic oxidase-like activity. Using Na2SeO3 as a precursor and glutathione as a reductant, biocompatibility SeNPs were synthesized by the wet chemical reduction method in the presence of bovine serum albumin (BSA). The results of structure characterization revealed that synthesized SeNPs were amorphous red elementary selenium with spherical morphology, and ranged in size from 25 to 70 nm size with a narrow distribution (41.4 ± 6.7 nm). The oxidase-like activity of the as-synthesized SeNPs was tested with 3,3',5,5'-tetramethylbenzidine (TMB) as a substrate. The results indicated that SeNPs could catalyze the oxidization of TMB by dissolved oxygen. These SeNPs showed an optimum catalytic activity at pH 4 and 30 °C, and the oxidase-like activity was higher as the concentration of SeNPs increased and the size of SeNPs decreased. The Michaelis constant ( K m) values and maximal reaction velocity ( V max) of the SeNPs for TMB oxidation were 0.0083 mol/L and 3.042 μmol/L min, respectively.

Thioredoxin and glutathione systems differ in parasitic and free-living platyhelminths

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Salinas Gustavo

2010-04-01

Full Text Available Abstract Background The thioredoxin and/or glutathione pathways occur in all organisms. They provide electrons for deoxyribonucleotide synthesis, function as antioxidant defenses, in detoxification, Fe/S biogenesis and participate in a variety of cellular processes. In contrast to their mammalian hosts, platyhelminth (flatworm parasites studied so far, lack conventional thioredoxin and glutathione systems. Instead, they possess a linked thioredoxin-glutathione system with the selenocysteine-containing enzyme thioredoxin glutathione reductase (TGR as the single redox hub that controls the overall redox homeostasis. TGR has been recently validated as a drug target for schistosomiasis and new drug leads targeting TGR have recently been identified for these platyhelminth infections that affect more than 200 million people and for which a single drug is currently available. Little is known regarding the genomic structure of flatworm TGRs, the expression of TGR variants and whether the absence of conventional thioredoxin and glutathione systems is a signature of the entire platyhelminth phylum. Results We examine platyhelminth genomes and transcriptomes and find that all platyhelminth parasites (from classes Cestoda and Trematoda conform to a biochemical scenario involving, exclusively, a selenium-dependent linked thioredoxin-glutathione system having TGR as a central redox hub. In contrast, the free-living platyhelminth Schmidtea mediterranea (Class Turbellaria possesses conventional and linked thioredoxin and glutathione systems. We identify TGR variants in Schistosoma spp. derived from a single gene, and demonstrate their expression. We also provide experimental evidence that alternative initiation of transcription and alternative transcript processing contribute to the generation of TGR variants in platyhelminth parasites. Conclusions Our results indicate that thioredoxin and glutathione pathways differ in parasitic and free-living flatworms and

Thioredoxin and glutathione systems differ in parasitic and free-living platyhelminths

Science.gov (United States)

2010-01-01

Background The thioredoxin and/or glutathione pathways occur in all organisms. They provide electrons for deoxyribonucleotide synthesis, function as antioxidant defenses, in detoxification, Fe/S biogenesis and participate in a variety of cellular processes. In contrast to their mammalian hosts, platyhelminth (flatworm) parasites studied so far, lack conventional thioredoxin and glutathione systems. Instead, they possess a linked thioredoxin-glutathione system with the selenocysteine-containing enzyme thioredoxin glutathione reductase (TGR) as the single redox hub that controls the overall redox homeostasis. TGR has been recently validated as a drug target for schistosomiasis and new drug leads targeting TGR have recently been identified for these platyhelminth infections that affect more than 200 million people and for which a single drug is currently available. Little is known regarding the genomic structure of flatworm TGRs, the expression of TGR variants and whether the absence of conventional thioredoxin and glutathione systems is a signature of the entire platyhelminth phylum. Results We examine platyhelminth genomes and transcriptomes and find that all platyhelminth parasites (from classes Cestoda and Trematoda) conform to a biochemical scenario involving, exclusively, a selenium-dependent linked thioredoxin-glutathione system having TGR as a central redox hub. In contrast, the free-living platyhelminth Schmidtea mediterranea (Class Turbellaria) possesses conventional and linked thioredoxin and glutathione systems. We identify TGR variants in Schistosoma spp. derived from a single gene, and demonstrate their expression. We also provide experimental evidence that alternative initiation of transcription and alternative transcript processing contribute to the generation of TGR variants in platyhelminth parasites. Conclusions Our results indicate that thioredoxin and glutathione pathways differ in parasitic and free-living flatworms and that canonical enzymes

Erythrocyte superoxide dismutase, glutathione peroxidase, and catalase activities and risk of coronary heart disease in generally healthy women: a prospective study.

Science.gov (United States)

Yang, Shuman; Jensen, Majken K; Rimm, Eric B; Willett, Walter; Wu, Tianying

2014-11-01

Erythrocyte antioxidant enzymes are major circulating antioxidant enzymes in the oxidative stress defense system. Few prospective studies have assessed the association between these enzymes and the risk of coronary heart disease (CHD) in generally healthy adults. We conducted a prospective nested case-control study of CHD among 32,826 women at baseline with 15 years of follow-up from 1989 to 2004 in the Nurses' Health Study. We investigated the association of baseline erythrocyte superoxide dismutase (SOD), glutathione peroxidase (GPx), and catalase (CAT) activities with the risk of CHD. A total of 365 cases and 728 controls were included in the analysis. Overall, the relative risks of CHD associated with 1-standard deviation higher SOD, GPx, and CAT activities were 1.07 (95% confidence interval (CI): 0.94, 1.22), 1.04 (95% CI: 0.91, 1.18), and 1.04 (95% CI: 0.92, 1.17), respectively. Multivariable adjustments did not change the associations appreciably. Fasting status did not modify the associations, with the exception that SOD activity was positively associated with the risk of CHD among participants who provided blood samples within 12 hours of fasting. Overall, activities of SOD, GPx, and CAT were not associated with CHD among women who were generally healthy at the time of blood collection. © The Author 2014. Published by Oxford University Press on behalf of the Johns Hopkins Bloomberg School of Public Health. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Redox regulation of antioxidant enzymes: post-translational modulation of catalase and glutathione peroxidase activity by resveratrol in diabetic rat liver.

Science.gov (United States)

Sadi, Gökhan; Bozan, Davut; Yildiz, Huseyin Bekir

2014-08-01

Resveratrol is a strong antioxidant that exhibits blood glucose-lowering effects, which might contribute to its usefulness in preventing complications associated with diabetes. The present study aimed to investigate resveratrol effects on catalase (CAT) and glutathione peroxidase (GPx) gene and protein expression, their phosphorylation states and activities in rat liver of STZ-induced diabetes. Diabetes increased the levels of total protein phosphorylation and p-CAT, while mRNA expression, protein levels, and activity were reduced. Although diabetes induced transcriptional repression over GPx, it did not affect the protein levels and activity. When resveratrol was administered to diabetic rats, an increase in activity was associated with an increase in p-GPx levels. Decrease in Sirtuin1 (SIRT1) and nuclear factor erythroid 2-related factor (Nrf2) and increase in nuclear factor kappa B (NFκB) gene expression in diabetes were associated with a decrease in CAT and GPx mRNA expression. A possible compensatory mechanism for reduced gene expression of antioxidant enzymes is proved to be nuclear translocation of redox-sensitive Nrf2 and NFκB in diabetes which is confirmed by the increase in nuclear and decrease in cytoplasmic protein levels of Nrf2 and NFκB. Taken together, these findings revealed that an increase in the oxidized state in diabetes intricately modified the cellular phosphorylation status and regulation of antioxidant enzymes. Gene regulation of antioxidant enzymes was accompanied by nuclear translocation of Nrf2 and NFκB. Resveratrol administration also activated a coordinated cytoprotective response against diabetes-induced changes in liver tissues.

Gene architecture and expression analyses provide insights into the role of glutathione peroxidases (GPXs) in bread wheat (Triticum aestivum L.).

Science.gov (United States)

Tyagi, Shivi; Himani; Sembi, Jaspreet K; Upadhyay, Santosh Kumar

2018-04-01

Glutathione peroxidases (GPXs) are redox sensor proteins that maintain a steady-state of H 2 O 2 in plant cells. They exhibit distinct sub-cellular localization and have diverse functionality in response to different stimuli. In this study, a total of 14 TaGPX genes and three splice variants were identified in the genome of Triticum aestivum and evaluated for various physicochemical properties. The TaGPX genes were scattered on the various chromosomes of the A, B, and D sub-genomes and clustered into five homeologous groups based on high sequence homology. The majority of genes were derived from the B sub-genome and localized on chromosome 2. The intron-exon organization, motif and domain architecture, and phylogenetic analyses revealed the conserved nature of TaGPXs. The occurrence of both development-related and stress-responsive cis-acting elements in the promoter region, the differential expression of these genes during various developmental stages, and the modulation of expression in the presence of biotic and abiotic stresses suggested their diverse role in T. aestivum. The majority of TaGPX genes showed higher expression in various leaf developmental stages. However, TaGPX1-A1 was upregulated in the presence of each abiotic stress treatment. A co-expression analysis revealed the interaction of TaGPXs with numerous development and stress-related genes, which indicated their vital role in numerous biological processes. Our study revealed the opportunities for further characterization of individual TaGPX proteins, which might be useful in designing future crop improvement strategies. Copyright © 2018 Elsevier GmbH. All rights reserved.

Selenium Sulfide

Science.gov (United States)

Selenium sulfide, an anti-infective agent, relieves itching and flaking of the scalp and removes the dry, ... Selenium sulfide comes in a lotion and is usually applied as a shampoo. As a shampoo, selenium ...

Effects of Ionizing Radiation and Glutathione Precursor on Antioxidant Enzyme and Cell Survival in Yeast

Energy Technology Data Exchange (ETDEWEB)

Kim, Jinkyu; Roh, Changhyun; Ryu, Taeho; Park, Jiyoung [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Nili, Michael A. [Oxiage Cosmeceutical Research Institute, Virginia (United States)

2013-05-15

Cells react to such an induced oxidative stress through scavenging the generated reactive oxygen species to reduce oxidative damage. Antioxidant enzymes such as glutathione peroxidase, catalase, and superoxide dismutase are immediately triggered for reactive oxygen species. N-acetyl-L-cysteine (NAC), a precursor of glutathione, is one of the antioxidants. The effect of NAC as an antioxidant and/or a cell rescue agent was investigated in the present study. Glutathione (GSH) is the most abundant intracellular thiol, which involves in antioxidant defense via direct interaction with ROS or via activities of detoxication enzymes like glutathione peroxidases (GPx). NAC flowed in the cell is converted to cysteine by deacetylation, that is supplied to the depleted GSH by oxidative stress. NAC prevents the depletion of GSH by radiation, increases the production of GSH, and improves enzymes activity such as GPx and alkaline phosphatase. Cell growth and survivorship and transcriptional level of glutathione gene are analyzed in two yeast strains exposed to combined treatment of NAC with gamma-rays. The effect of NAC on cell growth was measured during 72 hours. The cell growth was hampered by higher concentrations of NAC at stationary phase. NAC, however, didn't affect the cell division at the exponential phase. The survival of the cells decreased with radiation dose. The cell viability of the strain W303-1A was reduced significantly at the low dose (10 and 30 Gy). By comparison, the strain W303-1A was more sensitive to radiation with having a half lethal dose (LD{sub 50}) of about 20 Gy. The quantitative RT-PCR analysis showed that the transcriptional expression of antioxidant enzyme gene GPX1 increased after irradiation while the expression of the gene decreased by the combined treatment of NAC with 100 Gy radiation. The present study shows that NAC can directly scavenge ROS against oxidative stress in vivo. In conclusion, NAC can prevent radiation-induced oxidative

Effects of Ionizing Radiation and Glutathione Precursor on Antioxidant Enzyme and Cell Survival in Yeast

International Nuclear Information System (INIS)

Kim, Jinkyu; Roh, Changhyun; Ryu, Taeho; Park, Jiyoung; Nili, Michael A.

2013-01-01

Cells react to such an induced oxidative stress through scavenging the generated reactive oxygen species to reduce oxidative damage. Antioxidant enzymes such as glutathione peroxidase, catalase, and superoxide dismutase are immediately triggered for reactive oxygen species. N-acetyl-L-cysteine (NAC), a precursor of glutathione, is one of the antioxidants. The effect of NAC as an antioxidant and/or a cell rescue agent was investigated in the present study. Glutathione (GSH) is the most abundant intracellular thiol, which involves in antioxidant defense via direct interaction with ROS or via activities of detoxication enzymes like glutathione peroxidases (GPx). NAC flowed in the cell is converted to cysteine by deacetylation, that is supplied to the depleted GSH by oxidative stress. NAC prevents the depletion of GSH by radiation, increases the production of GSH, and improves enzymes activity such as GPx and alkaline phosphatase. Cell growth and survivorship and transcriptional level of glutathione gene are analyzed in two yeast strains exposed to combined treatment of NAC with gamma-rays. The effect of NAC on cell growth was measured during 72 hours. The cell growth was hampered by higher concentrations of NAC at stationary phase. NAC, however, didn't affect the cell division at the exponential phase. The survival of the cells decreased with radiation dose. The cell viability of the strain W303-1A was reduced significantly at the low dose (10 and 30 Gy). By comparison, the strain W303-1A was more sensitive to radiation with having a half lethal dose (LD 50 ) of about 20 Gy. The quantitative RT-PCR analysis showed that the transcriptional expression of antioxidant enzyme gene GPX1 increased after irradiation while the expression of the gene decreased by the combined treatment of NAC with 100 Gy radiation. The present study shows that NAC can directly scavenge ROS against oxidative stress in vivo. In conclusion, NAC can prevent radiation-induced oxidative stress by

Effects of cytotoxic cis- and trans-diammine monochlorido platinum(II) complexes on selenium-dependent redox enzymes and DNA

Czech Academy of Sciences Publication Activity Database

Lemmerhirt, H.; Behnisch, S.; Bodtke, A.; Lillig, Ch.H.; Pazderová, L.; Kašpárková, Jana; Brabec, Viktor; Bednarski, P.J.

2018-01-01

Roč. 178, JAN2018 (2018), s. 94-105 ISSN 0162-0134 R&D Projects: GA ČR GA17-09436S Institutional support: RVO:68081707 Keywords : glutathione-peroxidase * thioredoxin reductase Subject RIV: CE - Biochemistry OBOR OECD: Biochemistry and molecular biology Impact factor: 3.348, year: 2016

Enhanced antioxidant capacity following selenium supplemented antimalarial therapy in Plasmodium berghei infected mice

Science.gov (United States)

Adebayo, Abiodun Humphrey; Olasehinde, Grace Iyabo; Egbeola, Oluwaseun Ayodimeji; Yakubu, Omolara Faith; Adeyemi, Alaba Oladipupo; Adekeye, Bosede Temitope

2018-04-01

The effect of the co-administration of artemether, lumefantrine and selenium was studied in mice infected with Plasmodium bergheiparasite. The mice were divided into seven groups of six animals per group. All groups except A were parasitized. Group A (unparasitized/untreated) and B (parasitized/untreated) served as the positive and negative control respectively, these were administered with olive oil. Animals in groups C and D were treated with 8 and 48 mg/kg/bw of artemether and lumefantrine respectively while group E was treated with a combination of artemether and lumefantrine (8: 48 mg/kg/bw). Animals in group F were treated with 0.945 mg/kg/bw of selenium only and group G was treated with a combination of artemether, lumefantrine and selenium (8:48:0.945 mg/kg/bw). All the treatment was done for a three day period. These animals were subsequently anaesthetized and the organs were excised. Homogenates were prepared for aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), total protein, reduced Glutathione (GSH), superoxide dismutase (SOD), catalase (CAT) and malondialdehyde (MDA) assays. The results showed a significant (pcells in group G when compared with group B. It may be concluded that the combination of artemether, lumefantrine and selenium showed a more potent effect against the parasite than the group treated with artemether and lumefantrine, thus, helps to combat post-infection oxidative stress in susceptible cells.

Single-bilayer graphene oxide sheet tolerance and glutathione redox system significance assessment in faba bean (Vicia faba L.)

International Nuclear Information System (INIS)

Anjum, Naser A.; Singh, Neetu; Singh, Manoj K.; Shah, Zahoor A.; Duarte, Armando C.; Pereira, Eduarda; Ahmad, Iqbal

2013-01-01

Adsorbents based on single-bilayer graphene oxide sheet (hereafter termed “graphene oxide”) are widely used in contaminated environments cleanup which may easily open the avenues for their entry to different environmental compartments, exposure to organisms and their subsequent transfer to human/animal food chain. Considering a common food crop—faba bean (Vicia faba L.) germinating seedlings as a model plant system, this study assesses the V. faba-tolerance to different concentrations (0, 100, 200, 400, 800, and 1600 mg L −1 ) of graphene oxide (0.5–5 μm) and evaluates glutathione (γ-glutamyl-cysteinyl-glycine) redox system significance in this context. The results showed significantly increased V. faba sensitivity under three graphene oxide concentrations (in order of impact: 1,600 > 200 > 100 mg graphene oxide L −1 ), which was accompanied by decreased glutathione redox (reduced glutathione-to-oxidized glutathione) ratio, reduced glutathione pool, as well as significant and equally elevated activities of glutathione-regenerating (glutathione reductase) and glutathione-metabolizing (glutathione peroxidase; glutathione sulfo-transferase) enzymes. Contrarily, the two graphene oxide concentrations (in order of impact: 800 > 400 graphene oxide mg L −1 ) yielded promising results; where, significant improvements in V. faba health status (measured as increased graphene oxide tolerance) were clearly perceptible with increased ratio of the reduced glutathione-to-oxidized glutathione, reduced glutathione pool and glutathione reductase activity but decreased activities of glutathione-metabolizing enzymes. It is inferred that V. faba seedlings-sensitivity and/or tolerance to graphene oxide concentrations depends on both the cellular redox state (reduced glutathione-to-oxidized glutathione ratio) and the reduced glutathione pool which in turn are controlled by a finely tuned modulation of the coordination between glutathione-regenerating and glutathione

Single-bilayer graphene oxide sheet tolerance and glutathione redox system significance assessment in faba bean (Vicia faba L.)

Energy Technology Data Exchange (ETDEWEB)

Anjum, Naser A. [University of Aveiro, Centre for Environmental and Marine Studies (CESAM) and Department of Chemistry (Portugal); Singh, Neetu; Singh, Manoj K. [University of Aveiro, Center for Mechanical Technology and Automation (TEMA) and Department of Mechanical Engineering (Portugal); Shah, Zahoor A. [University of Toledo, Department of Medicinal and Biological Chemistry, College of Pharmacy and Pharmaceutical Sciences (United States); Duarte, Armando C.; Pereira, Eduarda; Ahmad, Iqbal, E-mail: ahmadr@ua.pt [University of Aveiro, Centre for Environmental and Marine Studies (CESAM) and Department of Chemistry (Portugal)

2013-07-15

Adsorbents based on single-bilayer graphene oxide sheet (hereafter termed 'graphene oxide') are widely used in contaminated environments cleanup which may easily open the avenues for their entry to different environmental compartments, exposure to organisms and their subsequent transfer to human/animal food chain. Considering a common food crop-faba bean (Vicia faba L.) germinating seedlings as a model plant system, this study assesses the V. faba-tolerance to different concentrations (0, 100, 200, 400, 800, and 1600 mg L{sup -1}) of graphene oxide (0.5-5 {mu}m) and evaluates glutathione ({gamma}-glutamyl-cysteinyl-glycine) redox system significance in this context. The results showed significantly increased V. faba sensitivity under three graphene oxide concentrations (in order of impact: 1,600 > 200 > 100 mg graphene oxide L{sup -1}), which was accompanied by decreased glutathione redox (reduced glutathione-to-oxidized glutathione) ratio, reduced glutathione pool, as well as significant and equally elevated activities of glutathione-regenerating (glutathione reductase) and glutathione-metabolizing (glutathione peroxidase; glutathione sulfo-transferase) enzymes. Contrarily, the two graphene oxide concentrations (in order of impact: 800 > 400 graphene oxide mg L{sup -1}) yielded promising results; where, significant improvements in V. faba health status (measured as increased graphene oxide tolerance) were clearly perceptible with increased ratio of the reduced glutathione-to-oxidized glutathione, reduced glutathione pool and glutathione reductase activity but decreased activities of glutathione-metabolizing enzymes. It is inferred that V. faba seedlings-sensitivity and/or tolerance to graphene oxide concentrations depends on both the cellular redox state (reduced glutathione-to-oxidized glutathione ratio) and the reduced glutathione pool which in turn are controlled by a finely tuned modulation of the coordination between glutathione-regenerating and

POTENTIAL ESTROGENIC EFFECTS OF BISPHENOL-A IN MALE RATS AND BENEFICIAL ADMINISTRATION OF SOME ANTIOXIDANTS

International Nuclear Information System (INIS)

MAZEN, G.M.A.

2008-01-01

Bisphenol-A is a chemical compound which is used primarily as a monomer in the manufacture of numerous chemical products. The objective of this study was to evaluate potential harmful effects of bisphenol-A on reproductive system of male rats and was designed to clarify the ability of zinc or selenium to improve this perturbation in the reproductive function of rats.As a result of bisphenol-A treatment, number of sperms, testis total protein, glutathione and glutathione peroxidase were decreased significantly. This effect was concomitant with a significant decrease in serum testosterone level. On the other hand, bisphenol-A caused a significant elevation in the abnormality of sperm (sperm malformed head or tail or head and tail) and testis total lipid. However, a significant increment was obtained in serum FSH, LH, PRL, E2 and progesterone levels when compared with their corresponding normal control rats.Moreover, the administration of zinc or selenium to treated rats with bisphenol-A rats led to a remarkable amelioration in all previous parameters

Effects of two different high doses of irradiation on antioxidant system in the liver of guinea pigs.

Science.gov (United States)

Guney, Yildiz; Bukan, Neslihan; Dizman, Aysen; Hicsonmez, Ayse; Bilgihan, Ayse

2004-03-01

To examine the state of the oxidant-antioxidant system in the liver of guinea pig caused by high doses of ionizing radiation in the early period. The research was carried out on guinea pigs irradiated with the doses of 8 Gy (group 2) or 15 Gy (group 3) (single dose/whole body) in comparison with control group (group 1). The levels of thiobarbituric acid reactive substances (TBARS) and glutathione (GSH), the activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px) and the levels of selenium in the liver were measured. TBARS levels in the irradiated animals were markedly higher than those in controls. In group 3, GSH levels and GSH-Px activity were significantly increased while activity of SOD and CAT were significantly decreased compared to groups 1 and 2. Liver selenium levels were not influenced by irradiation. The data have shown that gamma-irradiation at the doses of 8 Gy or 15 Gy results in significant increase in free radical formation while antioxidant enzymes were affected only at a dose of 15 Gy.

Cardioprotective Effect of Aloe vera Biomacromolecules Conjugated with Selenium Trace Element on Myocardial Ischemia-Reperfusion Injury in Rats.

Science.gov (United States)

Yang, Yang; Yang, Ming; Ai, Fen; Huang, Congxin

2017-06-01

The present study was undertaken to evaluate the cardioprotection potential and underlying molecular mechanism afforded by a selenium (Se) polysaccharide (Se-AVP) from Aloe vera in the ischemia-reperfusion (I/R) model of rats in vivo. Myocardial I/R injury was induced by occluding the left anterior descending coronary artery (LAD) for 30 min followed by 2-h continuous reperfusion. Pretreatment with Se-AVP (100, 200, and 400 mg/kg) attenuated myocardial damage, as evidenced by reduction of the infarct sizes, increase in serum and myocardial endogenous antioxidants (superoxide dismutase (SOD), glutathione peroxidase (GSH), and catalase (CAT)), and decrease in the malondialdehyde (MDA) level in the rats suffering I/R injury. This cardioprotective activity afforded by Se-AVP is further supported by the decreased levels of cardiac marker enzymes creatine kinase (CK) and lactate dehydrogenase (LDH), as well as the rise of myocardial Na + -K + -ATPase and Ca 2+ -Mg 2+ -ATPase activities in I/R rats. Additionally, cardiomyocytic apoptosis was measured by terminal-deoxynucleotidyl transferase-mediated nick end labeling (TUNEL) staining and the result showed that the percent of TUNEL-positive cells in myocardium of Se-AVP-treated groups was lower than I/R rats. In conclusion, we clearly demonstrated that Se-AVP had a protective effect against myocardial I/R injury in rats by augmenting endogenous antioxidants and protecting rat hearts from oxidative stress-induced myocardial apoptosis.

Impact of glutathione peroxidase-1 deficiency on macrophage foam cell formation and proliferation: implications for atherogenesis.

Directory of Open Access Journals (Sweden)

Fei Cheng

Full Text Available Clinical and experimental evidence suggests a protective role for the antioxidant enzyme glutathione peroxidase-1 (GPx-1 in the atherogenic process. GPx-1 deficiency accelerates atherosclerosis and increases lesion cellularity in ApoE(-/- mice. However, the distribution of GPx-1 within the atherosclerotic lesion as well as the mechanisms leading to increased macrophage numbers in lesions is still unknown. Accordingly, the aims of the present study were (1 to analyze which cells express GPx-1 within atherosclerotic lesions and (2 to determine whether a lack of GPx-1 affects macrophage foam cell formation and cellular proliferation. Both in situ-hybridization and immunohistochemistry of lesions of the aortic sinus of ApoE(-/- mice after 12 weeks on a Western type diet revealed that both macrophages and - even though to a less extent - smooth muscle cells contribute to GPx-1 expression within atherosclerotic lesions. In isolated mouse peritoneal macrophages differentiated for 3 days with macrophage-colony-stimulating factor (MCSF, GPx-1 deficiency increased oxidized low density-lipoprotein (oxLDL induced foam cell formation and led to increased proliferative activity of peritoneal macrophages. The MCSF- and oxLDL-induced proliferation of peritoneal macrophages from GPx-1(-/-ApoE(-/- mice was mediated by the p44/42 MAPK (p44/42 mitogen-activated protein kinase, namely ERK1/2 (extracellular-signal regulated kinase 1/2, signaling pathway as demonstrated by ERK1/2 signaling pathways inhibitors, Western blots on cell lysates with primary antibodies against total and phosphorylated ERK1/2, MEK1/2 (mitogen-activated protein kinase kinase 1/2, p90RSK (p90 ribosomal s6 kinase, p38 MAPK and SAPK/JNK (stress-activated protein kinase/c-Jun N-terminal kinase, and immunohistochemistry of mice atherosclerotic lesions with antibodies against phosphorylated ERK1/2, MEK1/2 and p90RSK. Representative effects of GPx-1 deficiency on both macrophage proliferation and

A chloroplast-localized and auxin-induced glutathione S-transferase from phreatophyte Prosopis juliflora confer drought tolerance on tobacco.

Science.gov (United States)

George, Suja; Venkataraman, Gayatri; Parida, Ajay

2010-03-01

Plant growth and productivity are adversely affected by various abiotic stress factors. In our previous study, we used Prosopis juliflora, a drought-tolerant tree species of Fabaceae, as a model plant system for mining genes functioning in abiotic stress tolerance. Large-scale random EST sequencing from a cDNA library obtained from drought-stressed leaves of 2-month-old P. juliflora plants resulted in identification of three different auxin-inducible glutathione S-transferases. In this paper, we report the cellular localization and the ability to confer drought tolerance in transgenic tobacco of one of these GSTs (PjGSTU1). PjGSTU1 was overexpressed in Escherichia coli and GST and GPX activities in total protein samples were assayed and compared with controls. The results indicated that PjGSTU1 protein forms a functional homo-dimer in recombinant bacteria with glutathione transferase as well as glutathione peroxidase activities. PjGSTU1 transgenic tobacco lines survived better under conditions of 15% PEG stress compared with control un-transformed plants. In vivo localization studies for PjGSTU1 using GFP fusion revealed protein localization in chloroplasts of transgenic plants. The peroxidase activity of PjGSTU1 and its localization in the chloroplast indicates a possible role for PjGSTU1 in ROS removal. Copyright 2009 Elsevier GmbH. All rights reserved.

Mice Deficient in Both Mn Superoxide Dismutase and Glutathione Peroxidase-1 Have Increased Oxidative Damage and a Greater Incidence of Pathology but No Reduction in Longevity

Science.gov (United States)

Zhang, Yiqiang; Ikeno, Yuji; Qi, Wenbo; Chaudhuri, Asish; Li, Yan; Bokov, Alex; Thorpe, Suzanne R.; Baynes, John W.; Epstein, Charles; Richardson, Arlan

2009-01-01

To test the impact of increased mitochondrial oxidative stress as a mechanism underlying aging and age-related pathologies, we generated mice with a combined deficiency in two mitochondrial-localized antioxidant enzymes, Mn superoxide dismutase (MnSOD) and glutathione peroxidase-1 (Gpx-1). We compared life span, pathology, and oxidative damage in Gpx1−/−, Sod2+/−Gpx1+/−, Sod2+/−Gpx1−/−, and wild-type control mice. Oxidative damage was elevated in Sod2+/−Gpx1−/− mice, as shown by increased DNA oxidation in liver and skeletal muscle and increased protein oxidation in brain. Surprisingly, Sod2+/−Gpx1−/− mice showed no reduction in life span, despite increased levels of oxidative damage. Consistent with the important role for oxidative stress in tumorigenesis during aging, the incidence of neoplasms was significantly increased in the older Sod2+/−Gpx1−/− mice (28–30 months). Thus, these data do not support a significant role for increased oxidative stress as a result of compromised mitochondrial antioxidant defenses in modulating life span in mice and do not support the oxidative stress theory of aging. PMID:19776219

Glutathione.

Science.gov (United States)

Noctor, Graham; Queval, Guillaume; Mhamdi, Amna; Chaouch, Sejir; Foyer, Christine H

2011-01-01

Glutathione is a simple sulfur compound composed of three amino acids and the major non-protein thiol in many organisms, including plants. The functions of glutathione are manifold but notably include redox-homeostatic buffering. Glutathione status is modulated by oxidants as well as by nutritional and other factors, and can influence protein structure and activity through changes in thiol-disulfide balance. For these reasons, glutathione is a transducer that integrates environmental information into the cellular network. While the mechanistic details of this function remain to be fully elucidated, accumulating evidence points to important roles for glutathione and glutathione-dependent proteins in phytohormone signaling and in defense against biotic stress. Work in Arabidopsis is beginning to identify the processes that govern glutathione status and that link it to signaling pathways. As well as providing an overview of the components that regulate glutathione homeostasis (synthesis, degradation, transport, and redox turnover), the present discussion considers the roles of this metabolite in physiological processes such as light signaling, cell death, and defense against microbial pathogen and herbivores.

The effect of alcohol and hydrogen peroxide on liver hepcidin gene expression in mice lacking antioxidant enzymes, glutathione peroxidase-1 or catalase.

Science.gov (United States)

Harrison-Findik, Duygu Dee; Lu, Sizhao

2015-05-06

This study investigates the regulation of hepcidin, the key iron-regulatory molecule, by alcohol and hydrogen peroxide (H2O2) in glutathione peroxidase-1 (gpx-1(-/-)) and catalase (catalase(-/-)) knockout mice. For alcohol studies, 10% ethanol was administered in the drinking water for 7 days. Gpx-1(-/-) displayed significantly higher hepatic H2O2 levels than catalase(-/-) compared to wild-type mice, as measured by 2'-7'-dichlorodihydrofluorescein diacetate (DCFH-DA). The basal level of liver hepcidin expression was attenuated in gpx-1(-/-) mice. Alcohol increased H2O2 production in catalase(-/-) and wild-type, but not gpx-1(-/-), mice. Hepcidin expression was inhibited in alcohol-fed catalase(-/-) and wild-type mice. In contrast, alcohol elevated hepcidin expression in gpx-1(-/-) mice. Gpx-1(-/-) mice also displayed higher level of basal liver CHOP protein expression than catalase(-/-) mice. Alcohol induced CHOP and to a lesser extent GRP78/BiP expression, but not XBP1 splicing or binding of CREBH to hepcidin gene promoter, in gpx-1(-/-) mice. The up-regulation of hepatic ATF4 mRNA levels, which was observed in gpx-1(-/-) mice, was attenuated by alcohol. In conclusion, our findings strongly suggest that H2O2 inhibits hepcidin expression in vivo. Synergistic induction of CHOP by alcohol and H2O2, in the absence of gpx-1, stimulates liver hepcidin gene expression by ER stress independent of CREBH.

Biocompatibility selenium nanoparticles with an intrinsic oxidase-like activity

Energy Technology Data Exchange (ETDEWEB)

Guo, Leilei; Huang, Kaixun; Liu, Hongmei, E-mail: hmliu2004@126.com [Huazhong University of Science and Technology, School of Chemistry and Chemical Engineering (China)

2016-03-15

Selenium nanoparticles (SeNPs) are considered to be the new selenium supplement forms with high biological activity and low toxicity; however, the molecular mechanism by which SeNPs exert the biological function is unclear. Here, we reported that biocompatibility SeNPs possessed intrinsic oxidase-like activity. Using Na{sub 2}SeO{sub 3} as a precursor and glutathione as a reductant, biocompatibility SeNPs were synthesized by the wet chemical reduction method in the presence of bovine serum albumin (BSA). The results of structure characterization revealed that synthesized SeNPs were amorphous red elementary selenium with spherical morphology, and ranged in size from 25 to 70 nm size with a narrow distribution (41.4 ± 6.7 nm). The oxidase-like activity of the as-synthesized SeNPs was tested with 3,3′,5,5′-tetramethylbenzidine (TMB) as a substrate. The results indicated that SeNPs could catalyze the oxidization of TMB by dissolved oxygen. These SeNPs showed an optimum catalytic activity at pH 4 and 30 °C, and the oxidase-like activity was higher as the concentration of SeNPs increased and the size of SeNPs decreased. The Michaelis constant (K{sub m}) values and maximal reaction velocity (V{sub max}) of the SeNPs for TMB oxidation were 0.0083 mol/L and 3.042 μmol/L min, respectively.

[Selenium treatment in thyreopathies].

Science.gov (United States)

Sotak, Štefan

Selenium (latin Selenium) is a micronutrient embedded in several proteins. In adults, the thyroid is the organ with the highest amount of selenium per gram of tissue. Selenium levels in the body depend on the characteristics of the population and its diet and geographic area. In the thyroid, selenium is required for the antioxidant function and for the metabolism of thyroid hormones. The literature suggests that selenium supplementation of patients with Hashimotos thyroiditis is associated with a reduction in antithyroperoxidase antibody levels. Selenium supplementation also in mild Graves orbitopathy is associated with delayed progression of ocular disorders. As a consequence of this observation The European Group on Graves Orbitopathy recommend six months selenium preparates supportive therapy for patients with mild form of Graves orbitopathy.Key words: Graves-Basedows disease - Hashimotos thyroiditis - selenium - supplementation.

Superoxide dismutase, catalase, glutathione peroxidase and gluthatione S-transferases M1 and T1 gene polymorphisms in three Brazilian population groups.

Science.gov (United States)

de Oliveira Hiragi, Cássia; Miranda-Vilela, Ana Luisa; Rocha, Dulce Maria Sucena; de Oliveira, Silviene Fabiana; Hatagima, Ana; de Nazaré Klautau-Guimarães, Maria

2011-01-01

Antioxidants such as superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPX1) reduce the oxidation rates in the organism. Gluthatione S-transferases (GSTs) play a vital role in phase 2 of biotransformation of many substances. Variation in the expression of these enzymes suggests individual differences for the degree of antioxidant protection and geographical differences in the distribution of these variants. We described the distribution frequency of CAT (21A/T), SOD2 (Ala9Val), GPX1 (Pro198Leu), GSTM1 and GSTT1 polymorphisms in three Brazilian population groups: Kayabi Amerindians (n = 60), Kalunga Afro-descendants (n = 72), and an urban mixed population from Federal District (n = 162). Frequencies of the variants observed in Kalunga (18% to 58%) and Federal District (33% to 63%) were similar to those observed in Euro and Afro-descendants, while in Kayabi (3% to 68%), depending on the marker, frequencies were similar to the ones found in different ethnic groups. Except for SOD2 in all population groups studied here, and for GPX1 in Kalunga, the genotypic distributions were in accordance with Hardy-Weinberg Equilibrium. These data can clarify the contribution of different ethnicities in the formation of mixed populations, such as that of Brazil. Moreover, outcomes will be valuable resources for future functional studies and for genetic studies in specific populations. If these studies are designed to comprehensively explore the role of these genetic polymorphisms in the etiology of human diseases they may help to prevent inconsistent genotype-phenotype associations in pharmacogenetic studies.

Oxidative stress protection and glutathione metabolism in response to hydrogen peroxide and menadione in riboflavinogenic fungus Ashbya gossypii.

Science.gov (United States)

Kavitha, S; Chandra, T S

2014-11-01

Ashbya gossypii is a plant pathogen and a natural overproducer of riboflavin and is used for industrial riboflavin production. A few literature reports depict a link between riboflavin overproduction and stress in this fungus. However, the stress protection mechanisms and glutathione metabolism are not much explored in A. gossypii. In the present study, an increase in the activity of catalase and superoxide dismutase was observed in response to hydrogen peroxide and menadione. The lipid peroxide and membrane lipid peroxide levels were increased by H2O2 and menadione, indicating oxidative damage. The glutathione metabolism was altered with a significant increase in oxidized glutathione (GSSG), glutathione peroxidase (GPX), glutathione S transferase (GST), and glutathione reductase (GR) and a decrease in reduced glutathione (GSH) levels in the presence of H2O2 and menadione. Expression of the genes involved in stress mechanism was analyzed in response to the stressors by semiquantitative RT-PCR. The messenger RNA (mRNA) levels of CTT1, SOD1, GSH1, YAP1, and RIB3 were increased by H2O2 and menadione, indicating the effect of stress at the transcriptional level. A preliminary bioinformatics study for the presence of stress response elements (STRE)/Yap response elements (YRE) depicted that the glutathione metabolic genes, stress genes, and the RIB genes hosted either STRE/YRE, which may enable induction of these genes during stress.

Mechanism of the reaction of ebselen with endogenous thiols : dihydrolipoate is a better cofactor than glutathione in the peroxidase activity of ebselen

NARCIS (Netherlands)

Haenen, G R; De Rooij, B M; Vermeulen, N P; Bast, A

The therapeutic effect of ebselen has been linked to its peroxidase activity. In the present study, the peroxidase activity of ebselen toward H2O2 with the endogenous thiols GSH and dihydrolipoate [L(SH)2] as cofactors was determined. When GSH was used, peroxide removal was described by a ter uni

Selenium

Science.gov (United States)

... Health Information Supplement Fact Sheets Frequently Asked Questions Making Decisions What you Need To Know About Supplements Dietary ... understand how selenium in food and dietary supplements affects heart health. Cognitive decline Blood selenium levels decrease as people age, ...

Effect of Zeolite, Selenium and Silicon on Yield, Yield Components and Some Physiological Traits of Canola under Salt Stress Conditions

Directory of Open Access Journals (Sweden)

A Bybordi

2016-07-01

chlorophyll, relative water content, catalase, peroxidase and superoxide dismutase activity, as well as malondialdehyde, sodium and potassium content in the leaves. The samples were immediately frozen in liquid nitrogen and kept in -80° C freezer. At the end of the growing season, agronomic traits such as silique number, seed number on silique, 1000- grain weight, grain yield, biological yield and harvest index were recorded. Total oil percentage and fatty acids (oleic, linolenic and linoleic percentage were measured. Results and Discussion The combined analysis of variance indicated that the effect of year was significant on all studied traits, except for silique number, grain number in silique, linoleic acid, chlorophyll content and peroxidase activity. In addition, the results showed that the main effect of zeolite, selenium and silicon were significant on all canola studied traits. However, relative water content and peroxidase activity were not affected by silicon application. Comparison of means indicated that triple interaction was significant at 1000- grain weight, grain yield, biological yield, chlorophyll content, photosynthesis rate, relative water content and antioxidant enzyme activity. Some traits such as 1000- grain weight, grain yield, biological yield, harvest index, oil percentage, linolenic percentage and superoxide dismutase activity as well as sodium content in leaves were found to be higher in the second year compared with the first year. Zeolite significantly increased silique number and grain number in silique. Furthermore, harvest index increased with the increase of zeolite level. According to the results, selenium increased silique number, grain number in silique and harvest index in canola plants. Silicon foliar application also significantly increased silique number, grain number in silique and harvest index. The highest chlorophyll contents, photosynthesis rate and relative water content were registered when zeolite was applied at 10% w: w and

Evaluation of the impact of genetic polymorphisms in glutathione-related genes on the association between methylmercury or n-3 polyunsaturated long chain fatty acids and risk of myocardial infarction: a case-control study

Directory of Open Access Journals (Sweden)

Norberg Margareta

2011-04-01

Full Text Available Abstract Background The n-3 polyunsaturated fatty acids eicosapentaenoic acid and docosahexaenoic acid, which are present in fish, are protective against myocardial infarction. However, fish also contains methylmercury, which influences the risk of myocardial infarction, possibly by generating oxidative stress. Methylmercury is metabolized by conjugation to glutathione, which facilitates elimination. Glutathione is also an antioxidant. Individuals with certain polymorphisms in glutathione-related genes may tolerate higher exposures to methylmercury, due to faster metabolism and elimination and/or better glutathione-associated antioxidative capacity. They would thus benefit more from the protective agents in fish, such as eicosapentaenoic+docosahexaenoic acid and selenium. The objective for this study was to elucidate whether genetic polymorphisms in glutathione-related genes modify the association between eicosapentaenoic+docosahexaenoic acid or methylmercury and risk of first ever myocardial infarction. Methods Polymorphisms in glutathione-synthesizing (glutamyl-cysteine ligase catalytic subunit, GCLC and glutamyl-cysteine ligase modifier subunit, GCLM or glutathione-conjugating (glutathione S-transferase P, GSTP1 genes were genotyped in 1027 individuals from northern Sweden (458 cases of first-ever myocardial infarction and 569 matched controls. The impact of these polymorphisms on the association between erythrocyte-mercury (proxy for methylmercury and risk of myocardial infarction, as well as between plasma eicosapentaenoic+docosahexaenoic acid and risk of myocardial infarction, was evaluated by conditional logistic regression. The effect of erythrocyte-selenium on risk of myocardial infarction was also taken into consideration. Results There were no strong genetic modifying effects on the association between plasma eicosapentaenoic+docosahexaenoic acid or erythrocyte-mercury and risk of myocardial infarction risk. When eicosapentaenoic

1-Methyl-4-phenylpyridinium-induced alterations of glutathione status in immortalized rat dopaminergic neurons

International Nuclear Information System (INIS)

Drechsel, Derek A.; Liang, L.-P.; Patel, Manisha

2007-01-01

Decreased glutathione levels associated with increased oxidative stress are a hallmark of numerous neurodegenerative diseases, including Parkinson's disease. GSH is an important molecule that serves as an anti-oxidant and is also a major determinant of cellular redox environment. Previous studies have demonstrated that neurotoxins can cause changes in reduced and oxidized GSH levels; however, information regarding steady state levels remains unexplored. The goal of this study was to characterize changes in cellular GSH levels and its regulatory enzymes in a dopaminergic cell line (N27) following treatment with the Parkinsonian toxin, 1-methyl-4-phenylpyridinium (MPP + ). Cellular GSH levels were initially significantly decreased 12 h after treatment, but subsequently recovered to values greater than controls by 24 h. However, oxidized glutathione (GSSG) levels were increased 24 h following treatment, concomitant with a decrease in GSH/GSSG ratio prior to cell death. In accordance with these changes, ROS levels were also increased, confirming the presence of oxidative stress. Decreased enzymatic activities of glutathione reductase and glutamate-cysteine ligase by 20-25% were observed at early time points and partly account for changes in GSH levels after MPP + exposure. Additionally, glutathione peroxidase activity was increased 24 h following treatment. MPP + treatment was not associated with increased efflux of glutathione to the medium. These data further elucidate the mechanisms underlying GSH depletion in response to the Parkinsonian toxin, MPP +

Probucol increases striatal glutathione peroxidase activity and protects against 3-nitropropionic acid-induced pro-oxidative damage in rats.

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Dirleise Colle

Full Text Available Huntington's disease (HD is an autosomal dominantly inherited neurodegenerative disease characterized by symptoms attributable to the death of striatal and cortical neurons. The molecular mechanisms mediating neuronal death in HD involve oxidative stress and mitochondrial dysfunction. Administration of 3-nitropropionic acid (3-NP, an irreversible inhibitor of the mitochondrial enzyme succinate dehydrogenase, in rodents has been proposed as a useful experimental model of HD. This study evaluated the effects of probucol, a lipid-lowering agent with anti-inflammatory and antioxidant properties, on the biochemical parameters related to oxidative stress, as well as on the behavioral parameters related to motor function in an in vivo HD model based on 3-NP intoxication in rats. Animals were treated with 3.5 mg/kg of probucol in drinking water daily for 2 months and, subsequently, received 3-NP (25 mg/kg i.p. once a day for 6 days. At the end of the treatments, 3-NP-treated animals showed a significant decrease in body weight, which corresponded with impairment on motor ability, inhibition of mitochondrial complex II activity and oxidative stress in the striatum. Probucol, which did not rescue complex II inhibition, protected against behavioral and striatal biochemical changes induced by 3-NP, attenuating 3-NP-induced motor impairments and striatal oxidative stress. Importantly, probucol was able to increase activity of glutathione peroxidase (GPx, an enzyme important in mediating the detoxification of peroxides in the central nervous system. The major finding of this study was that probucol protected against 3-NP-induced behavioral and striatal biochemical changes without affecting 3-NP-induced mitochondrial complex II inhibition, indicating that long-term probucol treatment resulted in an increased resistance against neurotoxic events (i.e., increased oxidative damage secondary to mitochondrial dysfunction. These data appeared to be of great

Selenium and Human Health

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M Abedi

2013-04-01

Full Text Available Introduction: Selenium is an essential element for human health and it is toxic at high concentrations. Selenium is a constituent component of selenoproteins that have enzymatic and structural roles in human biochemistry. Selenium is a best antioxidant and catalyst for production of thyroid hormone. This element has the key role in the immune function; prevention of AIDS progression and the deactivity of toxins. Furthermore, selenium is essential for sperm motility and can reduce abortions. Selenium deficiency was also associated with adverse mood states. The findings regarding cardiovascular disease risk related to selenium deficiency is unclear, though other conditions such as vascular inflammation, oxidative stress and selenium deficiency can cause this disease too. Moreover, consuming of 60 mg of selenium per day may be associated with reduction of cancer risk. In this study, a review of studies has been performed on the biochemical function of selenium toxicity, and its effects on human health. Furthermore, certain identified cancers associated with selenium have been discussed to absorb more attention to the status of this element and also as a guide for further studies. Selenium plays the dual character (useful and harmful in human health, and then it is necessary to determine the concentration of this element in body fluids and tissues. An appropriate method for routine measurement of selenium in clinical laboratories is electro thermal atomic absorption spectrometry (ETAAS with very low detection limit and good precision.

Selenium Content, Influential Factors Within the Plant and the Transformation of Different Selenium Specification

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LIU Yuan-yuan

2014-12-01

Full Text Available The paper collected relevant literatures on selenium and explored the function to plant, selenium content, influential factors and selenium specification and transformation. We believed that there should be more deep researches on function of selenium to plant. Approaches of molecular, genetic engineering and isotope could be employed to breed selenium rich crops and possibilities in practice. More efforts should be spent on the technologies research for improving selenium level in crops under natural soil conditions to sustainably utilize the selenium resources.

Prolonged fasting increases glutathione biosynthesis in postweaned northern elephant seals

Science.gov (United States)

Vázquez-Medina, José Pablo; Zenteno-Savín, Tania; Forman, Henry Jay; Crocker, Daniel E.; Ortiz, Rudy M.

2011-01-01

SUMMARY Northern elephant seals experience prolonged periods of absolute food and water deprivation (fasting) while breeding, molting or weaning. The postweaning fast in elephant seals is characterized by increases in the renin–angiotensin system, expression of the oxidant-producing protein Nox4, and NADPH oxidase activity; however, these increases are not correlated with increased oxidative damage or inflammation. Glutathione (GSH) is a potent reductant and a cofactor for glutathione peroxidases (GPx), glutathione-S transferases (GST) and 1-cys peroxiredoxin (PrxVI) and thus contributes to the removal of hydroperoxides, preventing oxidative damage. The effects of prolonged food deprivation on the GSH system are not well described in mammals. To test our hypothesis that GSH biosynthesis increases with fasting in postweaned elephant seals, we measured circulating and muscle GSH content at the early and late phases of the postweaning fast in elephant seals along with the activity/protein content of glutamate-cysteine ligase [GCL; catalytic (GCLc) and modulatory (GCLm) subunits], γ-glutamyl transpeptidase (GGT), glutathione disulphide reductase (GR), glucose-6-phosphate dehydrogenase (G6PDH), GST and PrxVI, as well as plasma changes in γ-glutamyl amino acids, glutamate and glutamine. GSH increased two- to four-fold with fasting along with a 40–50% increase in the content of GCLm and GCLc, a 75% increase in GGT activity, a two- to 2.5-fold increase in GR, G6PDH and GST activities and a 30% increase in PrxVI content. Plasma γ-glutamyl glutamine, γ-glutamyl isoleucine and γ-glutamyl methionine also increased with fasting whereas glutamate and glutamine decreased. Results indicate that GSH biosynthesis increases with fasting and that GSH contributes to counteracting hydroperoxide production, preventing oxidative damage in fasting seals. PMID:21430206

Selenium content of mushrooms.

Science.gov (United States)

Stijve, T

1977-07-29

The selenium contents of 83 species of wild mushrooms were determined by oxygen combustion of the sample, followed by conversion of selenite to bromopiazselenol and final estimation by electron capture gas-liquid chromatography. Selenium concentration were found to range from 0.012-20.0 mg/kg dry weight. Selenium content was species-dependent. High concentrations were found in Agaricaceae and in certain Boletaceae of the genus Tubiporus, whereas in Russulaceae, Amanitaceae and Cantharellaceae selenium-rich species were absent or rare. Ascomycetes and all mushrooms growing on wood had a very low selenium content. The highest selenium concentrations (up to 20 ppm) were found in Boletus (Tubiporus) edulis, a most popular edible mushroom. Analyses of various parts of carpophores of B. edulis, Suillus luteus and Amanita muscaria indicate that in all three species the stalk contains less selenium than the fleshy part of the cap. In Boletus and Suillus the highest selenium content was found in the tubes.

Immunoregulatory and antioxidant performance of alpha-tocopherol and selenium on human lymphocytes.

Science.gov (United States)

Lee, Chung-Yung Jetty; Wan, Jennifer Man-Fan

2002-05-01

The role of alpha-tocopherol (alpha-toco) and selenium (Se) on human lymphocyte oxidative stress and T-cells proliferation were studied by flow cytometry. We measured the hydrogen peroxide and glutathione levels in cultured human T-lymphocytes and the proliferation of their subsets: T-helper/inducer, T-suppressor/cytotoxic, and natural killer and interleukin-2 receptors upon stimulation by the mitogens phytohemaglutinin (PHA) and lipopolysaccharide (LPS). The results indicate that early stimulation by mitogens is affected by the glutathione and hydrogen peroxide status of the T-lymphocytes. The addition of 100 microM or 500 microM alpha-toco or 0.5 microM Se alone shows weak antioxidant and immunostimulant properties. When combined, an enhanced antioxidant and immunoregulatory effect was observed. The present findings indicate that alpha-toco and Se have interactive effects as oxygen radical scavengers, thus promoting human lymphocyte response to antigens. This suggests that micronutrient status is an important factor in considering when interpreting the results of in vitro assays of lymphocyte function.

Effect of high levels of organic selenium on glutation-peroxidase (GSH-Px activity in blood plasma of broilers

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Joksimović-Todorović Mirjana

2005-01-01

Full Text Available An experiment lasting 45 days was performed on 125 Hybro broilers divided into five groups. All compounds for broiler feed mixes used in the experiment contained 0.15 mg Se/kg, in the form of sodium selenite. The control group (K-group of broilers was fed mixes without added organic selenium, and the experimental groups with mixes to which selenium, in the form of selenized-yeast, was added in quantities of 2, 5, 10, or 15 mg/kg. Selenized yeast (ICN - Gaienika was obtained from beer yeast and contained 1.51, or 1.45 mg/g total, or organically bound selenium. At the beginning of the fattening period, GSH-Px plasma activity in broilers of the K-group ranged around 16.55 μkat/L, while GSH-Px plasma activity in broilers of experimental groups was statistically significantly higher, but without any major differences among the individual groups (on the average 25.53fjkat/L. In the blood plasma of K-group, GSH-Px activity dropped already in the second week of life and was maintained at a relatively constant level (about 10 μkat/L until the end of the experiment. The same phenomenon was observed in the experimental groups, but the trend of declining GSH-Px activity in blood plasma was more expressed, and, contrary to the control group, was expressed also in the later phases of the experiment. In the 3rd week of the fattening period, GSH-Px plasma activity in broilers of the control and experimental groups was relatively equal, and then the plasma activity of GSH-Px in broilers of the experimental groups decreased, but there were no major differences among the individual groups.

Serum concentrations of trace elements in patients with Crohn's disease receiving enteral nutrition.

Science.gov (United States)

Johtatsu, Tomoko; Andoh, Akira; Kurihara, Mika; Iwakawa, Hiromi; Tsujikawa, Tomoyuki; Kashiwagi, Atsunori; Fujiyama, Yoshihide; Sasaki, Masaya

2007-11-01

We investigated the trace element status in Crohn's disease (CD) patients receiving enteral nutrition, and evaluated the effects of trace element-rich supplementation. Thirty-one patients with CD were enrolled in this study. All patients were placed on an enteral nutrition regimen with Elental(R) (Ajinomoto pharmaceutical. Ltd., Tokyo, Japan). Serum selenium, zinc and copper concentrations were determined by atomic absorption spectroscopy. Serum selenoprotein P levels were determined by an ELISA system. Average serum levels of albumin, selenium, zinc and copper were 4.1 +/- 0.4 g/dl, 11.2 +/- 2.8 microg/dl, 71.0 +/- 14.8 microg/dl, and 112.0 +/- 25.6 microg/dl, respectively. In 9 patients of 31 CD patients, serum albumin levels were lower than the lower limit of the normal range. Serum selenium, zinc and copper levels were lower than lower limits in 12 patients, 9 patients and 1 patient, respectively. Serum selenium levels significantly correlated with both serum selenoprotein P levels and glutathione peroxidase activity. Supplementation of selenium (100 microg/day) and zinc (10 mg/day) for 2 months significantly improved the trace element status in CD patients. In conclusion, serum selenium and zinc levels are lower in many CD patients on long-term enteral nutrition. In these patients, supplementation of selenium and zinc was effective in improving the trace element status.

Selenium in edible mushrooms.

Science.gov (United States)

Falandysz, Jerzy

2008-01-01

Selenium is vital to human health. This article is a compendium of virtually all the published data on total selenium concentrations, its distribution in fruitbody, bioconcentration factors, and chemical forms in wild-grown, cultivated, and selenium-enriched mushrooms worldwide. Of the 190 species reviewed (belonging to 21 families and 56 genera), most are considered edible, and a few selected data relate to inedible mushrooms. Most of edible mushroom species examined until now are selenium-poor (cesarea, A. campestris, A. edulis, A. macrosporus, and A. silvaticus. A particularly rich source of selenium could be obtained from selenium-enriched mushrooms that are cultivated on a substrate fortified with selenium (as inorganic salt or selenized-yeast). The Se-enriched Champignon Mushroom could contain up to 30 or 110 microg Se/g dw, while the Varnished Polypore (Ganoderma lucidum) could contain up to 72 microg Se/g dw. An increasingly growing database on chemical forms of selenium of mushrooms indicates that the seleno-compounds identified in carpophore include selenocysteine, selenomethionine, Se-methylselenocysteine, selenite, and several unidentified seleno-compounds; their proportions vary widely. Some aspects of environmental selenium occurrence and human body pharmacokinetics and nutritional needs will also be briefly discussed in this review.

Peroxidase-like activity of nanocrystalline cobalt selenide and its application for uric acid detection

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Zhuang QQ

2017-04-01

Full Text Available Quan-Quan Zhuang,1 Zhi-Hang Lin,1 Yan-Cheng Jiang,1 Hao-Hua Deng,2 Shao-Bin He,1,3 Li-Ting Su,4 Xiao-Qiong Shi,2 Wei Chen2 1Department of Pharmacy, Affiliated Quanzhou First Hospital of Fujian Medical University, Quanzhou, 2Department of Pharmaceutical Analysis, School of Pharmacy, Fujian Medical University, Fuzhou, 3Department of Pharmacy, Quanzhou Infectious Disease Hospital, 4Department of Pharmaceutical Analysis, Quanzhou Medical College, Quanzhou, People’s Republic of China Abstract: Dendrite-like cobalt selenide nanostructures were synthesized from cobalt and selenium powder precursors by a solvothermal method in anhydrous ethylenediamine. The as-prepared nanocrystalline cobalt selenide was found to possess peroxidase-like activity that could catalyze the reaction of peroxidase substrates in the presence of H2O2. A spectrophotometric method for uric acid (UA determination was developed based on the nanocrystalline cobalt selenide-catalyzed coupling reaction between N-ethyl-N-(3-sulfopropyl-3-methylaniline sodium salt and 4-aminoantipyrine (4-AAP in the presence of H2O2. Under optimum conditions, the absorbance was proportional to the concentration of UA over the range of 2.0–40 µM with a detection limit of 0.5 µM. The applicability of the proposed method has been validated by determination of UA in human serum samples with satisfactory results. Keywords: enzyme mimics, cobalt selenide, peroxidase-like activity, uric acid, human serum

Selenium is critical for cancer-signaling gene expression but not cell proliferation in human colon Caco-2 cells.

Science.gov (United States)

Zeng, Huawei; Botnen, James H

2007-01-01

Selenium (Se) is a potential anticarcinogenic nutrient, and the essential role of Se in cell growth is well recognized but certain cancer cells appear to have acquired a survival advantage under conditions of Se-deficiency. To understand the molecular basis of Se-anticancer effects at nutritional doses (nmol/L) for cultured cells, we generated Se-deficient colon Caco-2 cells by gradually reducing serum in media because serum contains a trace amount of Se. The glutathione peroxidase (GPx) activity of Se-deficient Caco-2 cells was 10.8 mU/mg protein compared to 133.6 approximately 146.3 mU/mg protein in Caco-2 cells supplemented with 500 nmol/L selenite, SeMSC or SeMet (three tested Se-chemical forms) after 7-d culture in serum free media. Interestingly, there were no detectable differences in cell growth, cell cycle progression between Se-deficient cells and cells supplemented with 500 nmol/L Se. To examine differential cancer signaling-gene expression between Se-deficient and Se-supplemented cells, we employed a cancer signal pathway-specific array assay coupled with the real time PCR analysis. Our data demonstrate that although Caco-2 cells are resistant to Se deprivation, Se may exert its anticancer property through increasing the expression of humoral defense gene (A2M) and tumor suppressor-related genes (IGFBP3, HHIP) while decreasing pro-inflammatory gene (CXC L9, HSPB2) expression.

Relations between metals (Zn, Pb, Cd and Cu) and glutathione-dependent detoxifying enzymes in spiders from a heavy metal pollution gradient

Energy Technology Data Exchange (ETDEWEB)

Wilczek, Grazyna [Department of Animal Physiology and Ecotoxicology, University of Silesia, Bankowa 9, 40-007 Katowice (Poland); Babczynska, Agnieszka [Department of Animal Physiology and Ecotoxicology, University of Silesia, Bankowa 9, 40-007 Katowice (Poland); Augustyniak, Maria [Department of Animal Physiology and Ecotoxicology, University of Silesia, Bankowa 9, 40-007 Katowice (Poland); Migula, Pawel [Department of Animal Physiology and Ecotoxicology, University of Silesia, Bankowa 9, 40-007 Katowice (Poland)]. E-mail: migula@us.edu.pl

2004-12-01

We studied the relations between glutathione-dependent detoxifying enzymes and heavy metal burdens in the web-building spider Agelena labyrinthica (Agelenidae) and the wolf spider Pardosa lugubris (Lycosidae) from five meadow sites along a heavy metal pollution gradient. We assayed the activity of glutathione-S-transferase (GST) and glutathione peroxidases (GPOX, GSTPx), and glutathione (GSH) levels in both sexes. Except for GSH vs Pb content, we found significant correlations between GPOX and GSTPx activity and metal concentrations in females of A. labyrinthica. The highest activity of these enzymes measured in the web-building spiders was found in the individuals from the most polluted sites. In P. lugubris males significant correlations were found between GST and Pb and Zn concentrations, and between GPOX and GSTPx and the concentration of Cu. GST activity was higher in males collected from less polluted areas. Thus, detoxifying strategies against pollutants seemed to be sex-dependent. Actively hunting spiders had higher metal concentrations, maintaining lower activity of detoxifying enzymes and a lower glutathione level. - Capsule: Glutathione-linked enzyme activity in spiders from polluted areas depends on hunting strategy and sex.

Relations between metals (Zn, Pb, Cd and Cu) and glutathione-dependent detoxifying enzymes in spiders from a heavy metal pollution gradient

International Nuclear Information System (INIS)

Wilczek, Grazyna; Babczynska, Agnieszka; Augustyniak, Maria; Migula, Pawel

2004-01-01

We studied the relations between glutathione-dependent detoxifying enzymes and heavy metal burdens in the web-building spider Agelena labyrinthica (Agelenidae) and the wolf spider Pardosa lugubris (Lycosidae) from five meadow sites along a heavy metal pollution gradient. We assayed the activity of glutathione-S-transferase (GST) and glutathione peroxidases (GPOX, GSTPx), and glutathione (GSH) levels in both sexes. Except for GSH vs Pb content, we found significant correlations between GPOX and GSTPx activity and metal concentrations in females of A. labyrinthica. The highest activity of these enzymes measured in the web-building spiders was found in the individuals from the most polluted sites. In P. lugubris males significant correlations were found between GST and Pb and Zn concentrations, and between GPOX and GSTPx and the concentration of Cu. GST activity was higher in males collected from less polluted areas. Thus, detoxifying strategies against pollutants seemed to be sex-dependent. Actively hunting spiders had higher metal concentrations, maintaining lower activity of detoxifying enzymes and a lower glutathione level. - Capsule: Glutathione-linked enzyme activity in spiders from polluted areas depends on hunting strategy and sex

Experimental type 2 diabetes mellitus and acetaminophen toxic lesions: glutathione system indices changes

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Olga Furka

2017-11-01

Full Text Available Background. The goal of the research was to study the effect of acetaminophen on major glutathione part of antioxidant system indices in liver homogenate of rats with type 2 diabetes mellitus in time dynamics. Materials and methods. We conducted two series of experiments. In the first series toxic lesion was caused by a single intragastric administration of acetaminophen suspension in 2 % starch solution to animals in a dose of 1250 mg/kg (1/2 LD50. In the second series  the suspension of acetaminophen in 2 % starch solution in a dose of 55 mg/kg was given, which corresponds to the highest therapeutic dose during 7 days. Non-genetic form of experimental type 2 diabetes mellitus was modeled by Islam S., Choi H. method (2007. Activity of glutathione peroxidase (GPx and glutathione reductase (GR, and contents of reduced glutathione (GSH were determined in liver homogenate. Results. The obtained results have shown that GR and GPx activity actively decreased after acetaminophen administration in higher therapeutic doses to rats with type 2 DM. However, the changes were less pronounced than in rats with type 2 DM and acute acetaminophen toxic lesions. Conclusion. Results of the research have shown that acetaminophen administration to rats with type 2 DM causes a significant violation of compensatory mechanisms, especially of the enzyme and nonenzyme parts of antioxidant system.

Plasma levels of selenium-containing proteins in Inuit adults from Nunavik.

Science.gov (United States)

Achouba, Adel; Dumas, Pierre; Ouellet, Nathalie; Lemire, Mélanie; Ayotte, Pierre

2016-11-01

Selenium (Se) is highly abundant in marine foods traditionally consumed by Inuit of Nunavik (Northern Quebec, Canada) and accordingly, their Se intake is among the highest in the world. However, little is known regarding the biological implications of this high Se status in this Arctic indigenous population. We used a method combining affinity chromatography and inductively coupled plasma-mass spectrometry with quantification by post-column isotope dilution to determine total Se levels and concentrations of Se-containing proteins in archived plasma samples of Inuit adults who participated to the 2004 Nunavik Inuit Health Survey (N = 852). Amounts of mercury (Hg) associated with Se-containing proteins were also quantified. Results show that glutathione peroxidase 3 (GPx3), selenoprotein P (SelP) and selenoalbumin (SeAlb) represented respectively 25%, 52% and 23% of total plasma Se concentrations. In addition, small amounts of Hg co-eluted with each Se-containing protein and up to 50% of plasma Hg was associated to SelP. Total plasma Se concentrations (median = 139 μg L− 1; interquartile range (IQR) = 22.7 μg L− 1) were markedly lower and less variable than whole blood Se concentration (median = 261 μg L− 1, IQR = 166 μg L− 1). A non linear relation was observed between whole blood Se and plasma Se levels, with plasma Se concentrations leveling off at approximately 200 μg L− 1, whereas 16% and 3% of individuals exhibited whole blood concentrations higher than 500 μg L− 1 and 1000 μg L− 1, respectively. In contrast, a linear relationship was previously reported in communities consuming Brazil nuts which are rich Se, mainly present as selenomethionine. This suggests that a different selenocompound, possibly selenoneine, is present in the Arctic marine food chain and accumulates in the blood cellular fraction of Inuit.

Proteomic and activity profiles of ascorbate-glutathione cycle enzymes in germinating barley embryo

DEFF Research Database (Denmark)

Bønsager, Birgit Christine; Shahpiri, Azar; Finnie, Christine

2010-01-01

Enzymes involved in redox control are important during seed germination and seedling growth. Ascorbate-glutathione cycle enzymes in barley embryo extracts were monitored both by 2D-gel electrophoresis and activity measurements from 4 to 144 h post imbibition (PI). Strikingly different activity...... profiles were observed. No ascorbate peroxidase (APX) activity was present in mature seeds but activity was detected after 24 h PI and increased 14-fold up to 144 h PI. In contrast, dehydroascorbate reductase (DHAR) activity was present at 4 h PI and first decreased by 9-fold until 72 h PI followed by a 5......-fold increase at 144 h PI. Glutathione reductase and monodehydroascorbate reductase activities were also detected at 4 h PI, and showed modest increases of 1.8- and 2.7-fold, respectively, by 144 h PI. The combination of functional analysis with the proteomics approach enabled correlation...

Ebselen, a useful tool for understanding cellular redox biology and a promising drug candidate for use in human diseases.

Science.gov (United States)

Noguchi, Noriko

2016-04-01

Ebselen is an organoselenium compound with glutathione peroxidase (GPx)-like hydroperoxide reducing activity. Moreover, ebselen has its own unique reactivity, with functions that GPx does not have, since it reacts with many kinds of thiols other than glutathione. Ebselen may affect the thioredoxin systems, through which it may contribute to regulation of cell function. With high reactivity toward thiols, hydroperoxides, and peroxynitrite, ebselen has been used as a useful tool in research on cellular redox mechanisms. Unlike α-tocopherol, ebselen does not scavenge lipid peroxyl radicals, which is another advantage of ebselen for use as a research tool in comparison with radical scavenging antioxidants. Selenium is not released from the ebselen molecule, which explains the low toxicity of ebselen. To further understand the mechanism of cellular redox biology, it should be interesting to compare the effects of ebselen with that of selenoprotein P, which supplies selenium to GPx. New medical applications of ebselen as a drug candidate for human diseases such as cancer and diabetes mellitus as well as brain stroke and ischemia will be expected. Copyright © 2015 Elsevier Inc. All rights reserved.

Binary mixtures of mercury/ selenium, and lead/selenium

African Journals Online (AJOL)

Physiologically-based biokinetic models have been developed for predicting simultaneously the Absorption, Distribution, Metabolism and Elimination (ADME) properties of lead (Pb) and selenium (Se), and mercury (Hg) and selenium in a number of target tissues of humans. This was done for three population groups, ...

Chemical Form of Selenium in Naturally Selenium-Rich Lentils (Lens Culinaris L.) From Saskatchewan

Energy Technology Data Exchange (ETDEWEB)

Thavarajah, D.; Vandenberg, A.; George, G.N.; Pickering, I.J.

2009-06-04

Lentils (Lens culinaris L.) are a source of many essential dietary components and trace elements for human health. In this study we show that lentils grown in the Canadian prairies are additionally enriched in selenium, an essential micronutrient needed for general well-being, including a healthy immune system and protection against cancer. Selenium K near-edge X-ray absorption spectroscopy (XAS) has been used to examine the selenium biochemistry of two lentil cultivars grown in various locations in Saskatchewan, Canada. We observe significant variations in total selenium concentration with geographic location and cultivar; however, almost all the selenium (86--95%) in these field-grown lentils is present as organic selenium modeled as selenomethionine with a small component (5--14%) as selenate. As the toxicities of certain forms of arsenic and selenium are antagonistic, selenium-rich lentils may have a pivotal role to play in alleviating the chronic arsenic poisoning in Bangladesh.

Selenoprotein S/SEPS1 modifies endoplasmic reticulum stress in Z variant alpha1-antitrypsin deficiency.

LENUS (Irish Health Repository)

Kelly, Emer

2009-06-19

Z alpha(1)-antitrypsin (ZAAT) deficiency is a disease associated with emphysematous lung disease and also with liver disease. The liver disease of AAT deficiency is associated with endoplasmic reticulum (ER) stress. SEPS1 is a selenoprotein that, through a chaperone activity, decreases ER stress. To determine the effect of SEPS1 on ER stress in ZAAT deficiency, we measured activity of the grp78 promoter and levels of active ATF6 as markers of the unfolded protein response in HepG2 cells transfected with the mutant form of AAT, a ZAAT transgene. We evaluated levels of NFkappaB activity as a marker of the ER overload response. To determine the effect of selenium supplementation on the function of SEPS1, we investigated glutathione peroxidase activity, grp78 promoter activity, and NFkappaB activity in the presence or absence of selenium. SEPS1 reduced levels of active ATF6. Overexpression of SEPS1 also inhibited grp78 promoter and NFkappaB activity, and this effect was enhanced in the presence of selenium supplementation. This finding demonstrates a role for SEPS1 in ZAAT deficiency and suggests a possible therapeutic potential for selenium supplementation.

SELENIUM EFFECT UPON THE RATS' HEMATOPOIESIS IN THE SUBACUTE BENZENE INTOXICATION

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Pavle Randjelovic

2001-03-01

Full Text Available The antioxidants (selenium, vitamins C and E stabilize the cell membrane andprotect the cells from the action of free radicals. On the other hand, the antioxidantsreduce the effects of chemical and physical agenls. Bcsidcs, selenium has animportant role in Transporting electrons in the mitochondria and il is necessary for iheglulathione peroxidase function in the protection from apoplhosis. Benzene is auniversal solvent and has a wide application in chemical industry. Its toxicity ismanifested in the damages done to the central nervous syslem, liver, kidneys andhematopoiesis system. Tn this experiment the Wistar rats were used that wereclassified in three experimental groups regarding the quantity of the receivedselenium. Each group comprised ten animals of both sexes and after two weeks'treatment by selenium of 4,8 and 16 mcg, the animals had received benzene byinlraperiloneal administration in the dose of 1,2 ml/kg of the body weight. Thecounting of the shaped blood elements was done after the selenium pretreatment andafter the benzene intoxication. The obtained results poinl to increased number of alithe blood elements after the selenium pretreatment while after benzene adminislrationthere was a drastic drop of the number of erylhrocyles and leukocytes alongwith moderate lhrombocylopenia. After the sacrifice, Ihe hematopoiesis organs weretaken. The hislological findings of the bone marrow show the emergence ofdisturbances, especially of the red sort cells as well as an obvious fat degeneration which is particularly conspicuous in the second and third groups of animals. Therewas also some damage done to the spleen, especially of its red pulp along with thepresence of a greater number of fresh erythrocytes in the second and third groups.Only the changes were more drastic in the third group. The obtained results show thatselenium in higher concentrations increases the number of erytrocytes andleukocytes which proves that it stimulates highly

Diphenyl diselenide protects against methylmercury-induced inhibition of thioredoxin reductase and glutathione peroxidase in human neuroblastoma cells: a comparison with ebselen.

Science.gov (United States)

Meinerz, Daiane F; Branco, Vasco; Aschner, Michael; Carvalho, Cristina; Rocha, João Batista T

2017-09-01

Exposure to methylmercury (MeHg), an important environmental toxicant, may lead to serious health risks, damaging various organs and predominantly affecting the brain function. The toxicity of MeHg can be related to the inhibition of important selenoenzymes, such as glutathione peroxidase (GPx) and thioredoxin reductase (TrxR). Experimental studies have shown that selenocompounds play an important role as cellular detoxifiers and protective agents against the harmful effects of mercury. The present study investigated the mechanisms by which diphenyl diselenide [(PhSe) 2 ] and ebselen interfered with the interaction of mercury (MeHg) and selenoenzymes (TrxR and GPx) in an in vitro experimental model of cultured human neuroblastoma cells (SH-SY5Y). Our results established that (PhSe) 2 and ebselen increased the activity and expression of TrxR. In contrast, MeHg inhibited TrxR activity even at low doses (0.5 μm). Coexposure to selenocompounds and MeHg showed a protective effect of (PhSe) 2 on both the activity and expression of TrxR. When selenoenzyme GPx was evaluated, selenocompounds did not alter its activity or expression significantly, whereas MeHg inhibited the activity of GPx (from 1 μm). Among the selenocompounds only (PhSe) 2 significantly protected against the effects of MeHg on GPx activity. Taken together, these results indicate a potential use for ebselen and (PhSe) 2 against MeHg toxicity. Furthermore, for the first time, we have demonstrated that (PhSe) 2 caused a more pronounced upregulation of TrxR than ebselen in neuroblastoma cells, likely reflecting an important molecular mechanism involved in the antioxidant properties of this compound. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

Selenium essentials

CERN Document Server

Sams, Prashanth

2015-01-01

If you are a developer who wants to migrate from Selenium RC or any other automation tool to Selenium WebDriver, then this book is for you. Knowledge of automation tools is necessary to follow the examples in this book.

Diphenylmethyl selenocyanate attenuates malachite green induced oxidative injury through antioxidation & inhibition of DNA damage in mice

Science.gov (United States)

Das, Jayanta Kumar; Sarkar, Sibani; Hossain, Sk Ugir; Chakraborty, Pramita; Das, Rajat Kumar; Bhattacharya, Sudin

2013-01-01

Background & objectives: Malachite green (MG), an environmentally hazardous material, is used as a non permitted food colouring agent, especially in India. Selenium (Se) is an essential nutritional trace element required for animals and humans to guard against oxidative stress induced by xenobiotic compounds of diverse nature. In the present study, the role of the selenium compound diphenylmethyl selenocyanate (DMSE) was assessed on the oxidative stress (OS) induced by a food colouring agent, malachite green (MG) in vivo in mice. Methods: Swiss albino mice (Mus musculus) were intraperitoneally injected with MG at a standardized dose of 100 μg/ mouse for 30 days. DMSE was given orally at an optimum dose of 3 mg/kg b.w. in pre (15 days) and concomitant treatment schedule throughout the experimental period. The parameters viz. ALT, AST, LPO, GSH, GST, SOD, CAT, GPx, TrxR, CA, MN, MI and DNA damage have been evaluated. Results: The DMSE showed its potential to protect against MG induced hepatotoxicity by controlling the serum alanine aminotransferase and aspartate amino transferase (ALT and AST) levels and also ameliorated oxidative stress by modulating hepatic lipid peroxidation and different detoxifying and antioxidative enzymes such as glutathione-S-transferase (GST), superoxide dismutase (SOD), catalase (CAT), and also the selenoenzymes such as glutathione peroxidase (GPx) and thioredoxin reductase (TrxR) and reduced glutathione level which in turn reduced DNA damage. Interpretation & conclusions: The organo-selenium compound DMSE showed significant protection against MG induced heptotoxicity and DNA damage in murine model. Better protection was observed in pretreatment group than in the concomitant group. Further studies need to be done to understand the mechanism of action. PMID:23852297

Antioxidant response and metal accumulation in tissues of Iberian green frogs (Pelophylax perezi) inhabiting a deactivated uranium mine.

Science.gov (United States)

Marques, Sérgio M; Antunes, Sara C; Nunes, Bruno; Gonçalves, Fernando; Pereira, Ruth

2011-08-01

Human mining activities tend often to generate greatly impacted areas which remain contaminated for long periods of time, giving rise to extreme habitats. Mining sites are usually characterized for the production of metal rich effluents with very low pH. In this work we analyzed physical and chemical parameters of water from a deactivated uranium mine pond (M) and a reference site (REF) as well as their metal content. Furthermore, we determined and compared metal accumulation in liver, kidney, bones, muscle and skin of Pelophylax perezi from REF with P. perezi from M. We also determined the enzymatic activities of glutathione-S-transferases (GSTs), catalase (CAT), glutathione reductase (Gred), and glutathione peroxidase (GPx; both selenium-dependent and selenium-independent) in liver, kidney, lung and heart. Additionally, lipoperoxidation (LPO) was also assessed in the same tissues via thiobarbituric acid reactive substances (TBARS) assay and lactate dehydrogenase (LDH) activity was determined in muscle. Our results revealed that the majority of metals were in higher concentrations in tissues of organisms from M. This trend was especially evident for U whose content reached a difference of 1350 fold between REF and M organisms. None of the organs tested for antioxidant defenses revealed LPO, nonetheless, with exception for liver, all organs from the M frogs presented increased total GPx activity and selenium-dependent GPx. However, this response was significant only for the lung, probably as a consequence of the significant inhibition of CAT upstream and to cope with the subsequent increase in H(2)O(2). Lungs were the organs displaying greater responsiveness of the anti-oxidant stress system in frogs from the uranium mine area.

Arabidopsis thaliana peroxidase N

DEFF Research Database (Denmark)

Mirza, Osman Asghar; Henriksen, A; Ostergaard, L

2000-01-01

The structure of the neutral peroxidase from Arabidopsis thaliana (ATP N) has been determined to a resolution of 1.9 A and a free R value of 20.5%. ATP N has the expected characteristic fold of the class III peroxidases, with a C(alpha) r.m.s.d. of 0.82 A when compared with horseradish peroxidase C...

Early H2O2 Accumulation in Mesophyll Cells Leads to Induction of Glutathione during the Hyper-Sensitive Response in the Barley-Powdery Mildew Interaction1

Science.gov (United States)

Vanacker, Helene; Carver, Tim L.W.; Foyer, Christine H.

2000-01-01

H2O2 production and changes in glutathione, catalase, and peroxidase were followed in whole-leaf extracts from the susceptible (AlgS [Algerian/4* (F14) Man.(S)]; ml-a1 allele) and resistant (AlgR [Algerian/4* (F14) Man.(R)]; Ml-a1 allele) barley (Hordeum vulgare) isolines between 12 and 24 h after inoculation with powdery mildew (Blumeria graminis [DC]. Speer [syn. Erysiphe graminis DC] f.sp hordei Marchal). Localized papilla responses and cell death hypersensitive responses were not observed within the same cell. In hypersensitive response sites, H2O2 accumulation first occurred in the mesophyll underlying the attacked epidermal cell. Subsequently, H2O2 disappeared from the mesophyll and accumulated around attacked epidermal cells. In AlgR, transient glutathione oxidation coincided with H2O2 accumulation in the mesophyll. Subsequently, total foliar glutathione and catalase activities transiently increased in AlgR. These changes, absent from AlgS, preceded inoculation-dependent increases in peroxidase activity that were observed in both AlgR and AlgS at 18 h. An early intercellular signal precedes H2O2, and this elicits anti-oxidant responses in leaves prior to events leading to death of attacked cells. PMID:10938348

Selenium for preventing cancer

Directory of Open Access Journals (Sweden)

Gabriele Dennert

Full Text Available BACKGROUND: Selenium is a trace element essential to humans. Higher selenium exposure and selenium supplements have been suggested to protect against several types of cancers. OBJECTIVE: Two research questions were addressed in this review: What is the evidence for: 1. an aetiological relationship between selenium exposure and cancer risk in women and men?; 2. the efficacy of selenium supplementation for cancer prevention in women and men? SEARCH STRATEGY: We searched electronic databases and bibliographies of reviews and included publications. SELECTION CRITERIA: We included prospective observational studies to answer research question (a and randomised controlled trials (RCTs to answer research question (b. DATA COLLECTION AND ANALYSIS: We conducted random effects meta-analyses of epidemiological data when five or more studies were retrieved for a specific outcome. We made a narrative summary of data from RCTs. MAIN RESULTS: We included 49 prospective observational studies and six RCTs. In epidemiologic data, we found a reduced cancer incidence (summary odds ratio, OR, 0.69; 95% confidence interval, CI, 0.53 to 0.91 and mortality (OR 0.55, 95% CI 0.36 to 0.83 with higher selenium exposure. Cancer risk was more pronouncedly reduced in men (incidence: OR 0.66, 95% CI 0.42 to 1.05 than in women (incidence: OR 0.90, 95% CI 0.45 to 1.77. These findings have potential limitations due to study design, quality and heterogeneity of the data, which complicated the interpretation of the summary statistics. The RCTs found no protective efficacy of selenium yeast supplementation against non-melanoma skin cancer or L-selenomethionine supplementation against prostate cancer. Study results for the prevention of liver cancer with selenium supplements were inconsistent and studies had an unclear risk of bias. The results of the Nutritional Prevention of Cancer Trial (NPCT and SELECT raised concerns about possible harmful effects of selenium supplements. AUTHORS

Review on Nano SeleniumProduced by Bacteria

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LI Ji-xiang

2014-12-01

Full Text Available Selenium (Se is a kind of essential trace element for people and animal, while ionic state of selenium is toxic with high concentrations and will cause the selenium pollution. Nano-selenium is stable, nontoxic with higher biological activity. Application of bacteria reducing selenite or selenate to biological nano-selenium has great potential in selenium pollution control and nano-selenium production. This review summarizes the research progress of the red elemental nano-selenium reduced by bacteria including characteristics and application of nano-selenium, effects of carbon and nitrogen source, oxygen, temperature and pH in bacteria nano-selenium production, and molecular mechanisms of nano-selenium reduced by bacteria.

Why Nature Chose Selenium.

Science.gov (United States)

Reich, Hans J; Hondal, Robert J

2016-04-15

The authors were asked by the Editors of ACS Chemical Biology to write an article titled "Why Nature Chose Selenium" for the occasion of the upcoming bicentennial of the discovery of selenium by the Swedish chemist Jöns Jacob Berzelius in 1817 and styled after the famous work of Frank Westheimer on the biological chemistry of phosphate [Westheimer, F. H. (1987) Why Nature Chose Phosphates, Science 235, 1173-1178]. This work gives a history of the important discoveries of the biological processes that selenium participates in, and a point-by-point comparison of the chemistry of selenium with the atom it replaces in biology, sulfur. This analysis shows that redox chemistry is the largest chemical difference between the two chalcogens. This difference is very large for both one-electron and two-electron redox reactions. Much of this difference is due to the inability of selenium to form π bonds of all types. The outer valence electrons of selenium are also more loosely held than those of sulfur. As a result, selenium is a better nucleophile and will react with reactive oxygen species faster than sulfur, but the resulting lack of π-bond character in the Se-O bond means that the Se-oxide can be much more readily reduced in comparison to S-oxides. The combination of these properties means that replacement of sulfur with selenium in nature results in a selenium-containing biomolecule that resists permanent oxidation. Multiple examples of this gain of function behavior from the literature are discussed.

New challenge in the speciation of selenium. Measurement and production on nano selenium

Energy Technology Data Exchange (ETDEWEB)

Prokisch, J; Sztrik, A; Babka, B; Zommara, M; Daroczi, L [Debrecen University, Centre for Agricultural Sciences and Engineering, Debrecen (Hungary). Institute of Bio- and Environmental Energetics

2009-07-01

Complete text of publication follows. We have found that several species of probiotic bacteria also used in food industry for making yogurts is capable of producing spherical elemental selenium nanospheres having an average diameter in the range of 50-500 nm when 1-1000 mg/L selenium was added to the medium in the form of selenite ions. Elemental selenium produced thereby has a high degree of purity, is spherical, and its size and crystalline form depends on the bacterium species applied. We have found that some species of the probiotic yogurt bacteria (e.g. Bifidobacterium bifidum or Bifidobacterium longum) are capable of producing the grey crystalline form of elemental selenium which is so far unprecedented in the art for any bacteria capable of producing elemental selenium nanoparticles. Our finding, therefore, enables the first time the development of economical industrial bacterial fermentation based processes for the production of a high quality elemental selenium material comprising uniformly sized grey or red nanospheres having an average diameter in the range of 50-500 nm. The size and the crystalline form of the produced nanosized (50-500 nm) spherical particles is defined by the selected microorganism. This genetic pre-determination result in reproducible production of a material having individual characteristics which can be used in numerous fields of industry and research. The produced nano selenium could be a good raw material for a production of certified reference materials. The measurement of the produced elemental nanoselenium is a new challenge for the speciation analysis. A sample preparation and measurement method was developed and investigated for the analysis of different selenium forms by HPLC-AFS system. The atomic fluorescence (AFS) was a reliable and simple detection method for the elemental nano selenium. The elemental selenium can produce hydride in the system or can be converted to selenite with HCl/H{sub 2}O{sub 2} digestion.

Ascorbate Peroxidase and Catalase Activities and Their Genetic Regulation in Plants Subjected to Drought and Salinity Stresses

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Adriano Sofo

2015-06-01

Full Text Available Hydrogen peroxide (H2O2, an important relatively stable non-radical reactive oxygen species (ROS is produced by normal aerobic metabolism in plants. At low concentrations, H2O2 acts as a signal molecule involved in the regulation of specific biological/physiological processes (photosynthetic functions, cell cycle, growth and development, plant responses to biotic and abiotic stresses. Oxidative stress and eventual cell death in plants can be caused by excess H2O2 accumulation. Since stress factors provoke enhanced production of H2O2 in plants, severe damage to biomolecules can be possible due to elevated and non-metabolized cellular H2O2. Plants are endowed with H2O2-metabolizing enzymes such as catalases (CAT, ascorbate peroxidases (APX, some peroxiredoxins, glutathione/thioredoxin peroxidases, and glutathione sulfo-transferases. However, the most notably distinguished enzymes are CAT and APX since the former mainly occurs in peroxisomes and does not require a reductant for catalyzing a dismutation reaction. In particular, APX has a higher affinity for H2O2 and reduces it to H2O in chloroplasts, cytosol, mitochondria and peroxisomes, as well as in the apoplastic space, utilizing ascorbate as specific electron donor. Based on recent reports, this review highlights the role of H2O2 in plants experiencing water deficit and salinity and synthesizes major outcomes of studies on CAT and APX activity and genetic regulation in drought- and salt-stressed plants.

Arabidopsis thaliana peroxidase N

DEFF Research Database (Denmark)

Mirza, Osman Asghar; Henriksen, A; Ostergaard, L

2000-01-01

The structure of the neutral peroxidase from Arabidopsis thaliana (ATP N) has been determined to a resolution of 1.9 A and a free R value of 20.5%. ATP N has the expected characteristic fold of the class III peroxidases, with a C(alpha) r.m.s.d. of 0.82 A when compared with horseradish peroxidase C...... (HRP C). HRP C is 54% identical to ATP N in sequence. When the structures of four class III plant peroxidases are superimposed, the regions with structural differences are non-randomly distributed; all are located in one half of the molecule. The architecture of the haem pocket of ATP N is very similar...... to that of HRP C, in agreement with the low small-molecule substrate specificity of all class III peroxidases. The structure of ATP N suggests that the pH dependence of the substrate turnover will differ from that of HRP C owing to differences in polarity of the residues in the substrate-access channel. Since...

Blood selenium levels and contribution of food groups to selenium intake in adolescent girls in Iceland.

Science.gov (United States)

Gudmundsdottir, Edda Y; Gunnarsdottir, Ingibjorg; Thorlacius, Arngrimur; Reykdal, Olafur; Gunnlaugsdottir, Helga; Thorsdottir, Inga; Steingrimsdottir, Laufey

2012-01-01

Significant changes have been reported in dietary habits and food availability in Iceland that would be expected to compromise selenium intake and status, especially among young people. These include substantial decreases in the consumption of fish and milk, as well as the selenium content of imported wheat. The aim of this study was to assess selenium in the diet and whole blood of adolescent girls, as well as define the most important foods contributing to intake and blood concentrations of selenium. The subjects were 96 randomly selected girls, aged 16-20, who answered a validated food frequency questionnaire (FFQ) for dietary assessment. Selenium intake from each food group was calculated in µg/day. Blood samples were collected for measurement of whole blood selenium. Mean dietary selenium was 51±25 µg/day. Milk/dairy products, including cheese, contributed 36±14% of total dietary selenium; fish 18±12%; and bread/cereal products 13±6%. Mean whole blood selenium was 117±12 µg/l (range 90-208); nearly 90% of subjects were above the optimal level of 100 µg/l. Fish and bread/cereal products were the only foods significantly correlated with selenium in blood (r=0.32; P=0.002 and r=0.22; P=0.04, respectively) while no correlation was found with milk and dairy products in spite of their greater contribution to total selenium intake. In this population of Icelandic adolescent girls, selenium intake and status seem acceptable. Judging from associations between intake and blood levels, fish and cereals may be the most important contributors to blood selenium.

Blood selenium levels and contribution of food groups to selenium intake in adolescent girls in Iceland

Directory of Open Access Journals (Sweden)

Ingibjorg Gunnarsdottir

2012-08-01

Full Text Available Background/objectives: Significant changes have been reported in dietary habits and food availability in Iceland that would be expected to compromise selenium intake and status, especially among young people. These include substantial decreases in the consumption of fish and milk, as well as the selenium content of imported wheat. The aim of this study was to assess selenium in the diet and whole blood of adolescent girls, as well as define the most important foods contributing to intake and blood concentrations of selenium. Design: The subjects were 96 randomly selected girls, aged 16–20, who answered a validated food frequency questionnaire (FFQ for dietary assessment. Selenium intake from each food group was calculated in µg/day. Blood samples were collected for measurement of whole blood selenium. Results: Mean dietary selenium was 51±25 µg/day. Milk/dairy products, including cheese, contributed 36±14% of total dietary selenium; fish 18±12%; and bread/cereal products 13±6%. Mean whole blood selenium was 117±12 µg/l (range 90–208; nearly 90% of subjects were above the optimal level of 100 µg/l. Fish and bread/cereal products were the only foods significantly correlated with selenium in blood (r=0.32; P = 0.002 and r=0.22; P = 0.04, respectively while no correlation was found with milk and dairy products in spite of their greater contribution to total selenium intake. Conclusion: In this population of Icelandic adolescent girls, selenium intake and status seem acceptable. Judging from associations between intake and blood levels, fish and cereals may be the most important contributors to blood selenium.

The Importance of Antioxidant Micronutrients in Pregnancy

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Hiten D. Mistry

2011-01-01

Full Text Available Pregnancy places increased demands on the mother to provide adequate nutrition to the growing conceptus. A number of micronutrients function as essential cofactors for or themselves acting as antioxidants. Oxidative stress is generated during normal placental development; however, when supply of antioxidant micronutrients is limited, exaggerated oxidative stress within both the placenta and maternal circulation occurs, resulting in adverse pregnancy outcomes. The present paper summarises the current understanding of selected micronutrient antioxidants selenium, copper, zinc, manganese, and vitamins C and E in pregnancy. To summarise antioxidant activity of selenium is via its incorporation into the glutathione peroxidase enzymes, levels of which have been shown to be reduced in miscarriage and preeclampsia. Copper, zinc, and manganese are all essential cofactors for superoxide dismutases, which has reduced activity in pathological pregnancy. Larger intervention trials are required to reinforce or refute a beneficial role of micronutrient supplementation in disorders of pregnancies.

Microbial selenium sulfide reduction for selenium recovery from wastewater

NARCIS (Netherlands)

Hageman, S.P.W.; Weijden, van der R.D.; Stams, A.J.M.; Cappellen, van P.; Buisman, C.J.N.

2017-01-01

Microbial reduction of selenium sulfide (SeS2) is a key step in a new treatment process to recover selenium from selenate and selenite streams. In this process, selenate is first reduced to selenite, and subsequently selenite is reduced by sulfide and precipitates from the solution as SeS2. The

A fused selenium-containing protein with both GPx and SOD activities

International Nuclear Information System (INIS)

Yu, Huijun; Ge, Yan; Wang, Ying; Lin, Chi-Tsai; Li, Jing; Liu, Xiaoman; Zang, Tianzhu; Xu, Jiayun; Liu, Junqiu; Luo, Guimin; Shen, Jiacong

2007-01-01

As a safeguard against oxidative stress, the balance between the main antioxidant enzymes including superoxide dismutase (SOD), glutathione peroxidase (GPx), and catalase (CAT) was believed to be more important than any single one, for example, dual-functional SOD/CAT enzyme has been proved to have better antioxidant ability than either single enzyme. By combining traditional fusion protein technology with amino acid auxotrophic expression system, we generated a bifunctional enzyme with both GPx and SOD activities. It displayed better antioxidant ability than GPx or SOD. Such dual-functional enzymes could facilitate further studies of the cooperation of GPx and SOD and generation of better therapeutic agents

Dietary Selenium as a Modulator of PCB 126–Induced Hepatotoxicity in Male Sprague-Dawley Rats

Science.gov (United States)

Lai, Ian K.; Chai, Yingtao; Simmons, Donald; Watson, Walter H.; Tan, Rommel; Haschek, Wanda M.; Wang, Kai; Wang, Bingxuan; Ludewig, Gabriele; Robertson, Larry W.

2011-01-01

Homeostasis of selenium (Se), a critical antioxidant incorporated into amino acids and enzymes, is disrupted by exposure to aryl hydrocarbon receptor (AhR) agonists. Here we examined the importance of dietary Se in preventing the toxicity of the most toxic polychlorinated biphenyl congener, 3,3′,4,4′,5-pentachlorobiphenyl (PCB 126), a potent AhR agonist. Male Sprague-Dawley rats were fed a modified AIN-93 diet with differing dietary Se levels (0.02, 0.2, and 2 ppm). Following 3 weeks of acclimatization, rats from each dietary group were given a single ip injection of corn oil (vehicle), 0.2, 1, or 5 μmol/kg body weight PCB 126, followed 2 weeks later by euthanasia. PCB exposure caused dose-dependent increases in liver weight and at the highest PCB 126 dose decreases in whole body weight gains. Hepatic cytochrome P-450 (CYP1A1) activity was significantly increased even at the lowest dose of PCB 126, indicating potent AhR activation. PCB exposure diminished hepatic Se levels in a dose-dependent manner, and this was accompanied by diminished Se-dependent glutathione peroxidase activity. Both these effects were partially mitigated by Se supplementation. Conversely, thioredoxin (Trx) reductase activity and Trx oxidation state, although significantly diminished in the lowest dietary Se groups, were not affected by PCB exposure. In addition, PCB 126–induced changes in hepatic copper, iron, manganese, and zinc were observed. These results demonstrate that supplemental dietary Se was not able to completely prevent the toxicity caused by PCB 126 but was able to increase moderately the levels of several key antioxidants, thereby maintaining them roughly at normal levels. PMID:21865291

Beta-carotene reduces oxidative stress, improves glutathione metabolism and modifies antioxidant defense systems in lead-exposed workers

International Nuclear Information System (INIS)

Kasperczyk, Sławomir; Dobrakowski, Michał; Kasperczyk, Janusz; Ostałowska, Alina; Zalejska-Fiolka, Jolanta; Birkner, Ewa

2014-01-01

The aim of this study was to determine whether beta-carotene administration reduces oxidative stress and influences antioxidant, mainly glutathione-related, defense systems in workers chronically exposed to lead. The population consisted of two randomly divided groups of healthy male volunteers exposed to lead. Workers in the first group (reference group) were not administered any antioxidants, while workers in the second group (CAR group) were treated orally with 10 mg of beta-carotene once a day for 12 weeks. Biochemical analysis included measuring markers of lead-exposure and oxidative stress in addition to the levels and activities of selected antioxidants. After treatment, levels of malondialdehyde, lipid hydroperoxides and lipofuscin significantly decreased compared with the reference group. However, the level of glutathione significantly increased compared with the baseline. Treatment with beta-carotene also resulted in significantly decreased glutathione peroxidase activity compared with the reference group, while the activities of other glutathione-related enzymes and of superoxide dismutase were not significantly changed. However, the activities of glucose-6-phosphate dehydrogenase and catalase, as well as the level of alpha-tocopherol, were significantly higher after treatment compared with the baseline. Despite controversy over the antioxidant properties of beta-carotene in vivo, our findings showed reduced oxidative stress after beta-carotene supplementation in chronic lead poisoning. - Highlights: • Beta-carotene reduces oxidative stress in lead-exposed workers. • Beta-carotene elevates glutathione level in lead-exposed workers. • Beta-carotene administration could be beneficial in lead poisoning

Beta-carotene reduces oxidative stress, improves glutathione metabolism and modifies antioxidant defense systems in lead-exposed workers

Energy Technology Data Exchange (ETDEWEB)

Kasperczyk, Sławomir, E-mail: kaslav@mp.pl [Dept. of Biochemistry, School of Medicine with the Division of Dentistry, Medical University of Silesia, ul. Jordana 19, 41-808 Zabrze (Poland); Dobrakowski, Michał [Dept. of Biochemistry, School of Medicine with the Division of Dentistry, Medical University of Silesia, ul. Jordana 19, 41-808 Zabrze (Poland); Kasperczyk, Janusz [Dept. of Environmental Medicine and Epidemiology, School of Medicine with the Division of Dentistry, Medical University of Silesia, ul. Jordana 19, 41-808 Zabrze (Poland); Ostałowska, Alina; Zalejska-Fiolka, Jolanta; Birkner, Ewa [Dept. of Biochemistry, School of Medicine with the Division of Dentistry, Medical University of Silesia, ul. Jordana 19, 41-808 Zabrze (Poland)

2014-10-01

The aim of this study was to determine whether beta-carotene administration reduces oxidative stress and influences antioxidant, mainly glutathione-related, defense systems in workers chronically exposed to lead. The population consisted of two randomly divided groups of healthy male volunteers exposed to lead. Workers in the first group (reference group) were not administered any antioxidants, while workers in the second group (CAR group) were treated orally with 10 mg of beta-carotene once a day for 12 weeks. Biochemical analysis included measuring markers of lead-exposure and oxidative stress in addition to the levels and activities of selected antioxidants. After treatment, levels of malondialdehyde, lipid hydroperoxides and lipofuscin significantly decreased compared with the reference group. However, the level of glutathione significantly increased compared with the baseline. Treatment with beta-carotene also resulted in significantly decreased glutathione peroxidase activity compared with the reference group, while the activities of other glutathione-related enzymes and of superoxide dismutase were not significantly changed. However, the activities of glucose-6-phosphate dehydrogenase and catalase, as well as the level of alpha-tocopherol, were significantly higher after treatment compared with the baseline. Despite controversy over the antioxidant properties of beta-carotene in vivo, our findings showed reduced oxidative stress after beta-carotene supplementation in chronic lead poisoning. - Highlights: • Beta-carotene reduces oxidative stress in lead-exposed workers. • Beta-carotene elevates glutathione level in lead-exposed workers. • Beta-carotene administration could be beneficial in lead poisoning.

Biological selenium removal from wastewaters

NARCIS (Netherlands)

Lenz, M.

2008-01-01

In this thesis, microbial conversion of water-soluble, highly toxic forms of selenium (selenate, selenite) to less bioavailable elemental selenium was investigated. By the exploitation of different groups of microorganisms (selenium-respiring, nitrate-reducing and sulfate-reducing bacteria,

Effects of methylmercury exposure on glutathione metabolism, oxidative stress, and chromosomal damage in captive-reared common loon (Gavia immer) chicks

International Nuclear Information System (INIS)

Kenow, Kevin P.; Hoffman, David J.; Hines, Randy K.; Meyer, Michael W.; Bickham, John W.; Matson, Cole W.; Stebbins, Katie R.; Montagna, Paul; Elfessi, Abdulaziz

2008-01-01

We quantified the level of dietary mercury (Hg), delivered as methylmercury chloride (CH 3 HgCl), associated with negative effects on organ and plasma biochemistries related to glutathione (GSH) metabolism and oxidative stress, and chromosomal damage in captive-reared common loon (Gavia immer) chicks reared from hatch to 105 days. Mercury-associated effects related to oxidative stress and altered glutathione metabolism occurred at 1.2 μg Hg/g and 0.4 μg Hg/g, an ecologically relevant dietary mercury level, but not at 0.08 μg Hg/g. Among the variables that contributed most to dissimilarities in tissue chemistries between control and treatment groups were increased levels of oxidized glutathione (GSSG), GSH peroxidase, and the ratio of GSSG to GSH in brain tissue; increased levels of hepatic GSH; and decreased levels of hepatic glucose-6-phosphate dehydrogenase (G-6-PDH). Our results also suggest that chronic exposure to environmentally relevant dietary Hg levels did not result in statistically significant somatic chromosomal damage in common loon chicks. - Oxidative stress and altered glutathione metabolism were evident in common loon chicks exposed to ≥0.4 μg Hg as CH 3 HgCl per gram wet food intake

Impact of Selenium Addition to Animal Feeds on Human Selenium Status in Serbia

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Zoran Pavlovic

2018-02-01

Full Text Available Research conducted during the 1980s demonstrated Se deficiency in humans. Increased inclusion of selenium in animal feeds started from the year 2000 onwards. The aim of this study was to estimate the effects of selenium inclusion in animal feeds on human selenium status and dietary habits of the Serbian population related to food of animal origin. Plasma selenium concentration in healthy adult volunteers, including residents of one of the regions with the lowest (Eastern Serbia, n = 60 and of one of the regions with the highest Se serum levels reported in the past (Belgrade, n = 82, was determined by hydride generation atomic absorption spectrometry. Multivariate analysis was employed to determine the correlation between Se plasma levels and dietary intake data derived from food frequency questionnaires and laboratory tests. The mean plasma Se level of the participants was 84.3 ± 15.9 μg/L (range: 47.3–132.1 μg/L, while 46% of participants had plasma Se levels lower than 80 μg/L. Frequency of meat, egg, and fish consumption was significantly correlated with plasma selenium level (r = 0.437, p = 0.000. Selenium addition to animal feed in the quantity of 0.14 mg/kg contributed to the improvement of human plasma selenium levels by approximately 30 μg/L.

Selenium in diet

Science.gov (United States)

... how much of the mineral was in the soil where the plants grew. Brazil nuts are a very good source of selenium. Fish, shellfish , red meat, grains, eggs, chicken, liver, and garlic ... soil have higher levels of selenium. Brewer's yeast, wheat ...

Influence of dietary methionine on the metabolism of selenomethionine in rats

International Nuclear Information System (INIS)

Butler, J.A.; Beilstein, M.A.; Whanger, P.D.

1989-01-01

To determine the influence of methionine on selenomethionine (SeMet) metabolism, weanling male rats were fed for 8 wk a basal diet marginally deficient in sulfur amino acids, containing 2.0 micrograms selenium (Se)/g as DL-SeMet and supplemented with 0, 0.3, 0.6 or 1.2% DL-methionine. Increased dietary methionine caused decreased selenium deposition in all tissues examined but increased glutathione peroxidase activity in testes, liver and lungs. A positive correlation was found between dietary methionine and the calculated percentage of selenium associated with GSHPx. In a second experiment, 75 SeMet was injected into weanling male rats which had been fed the basal diet containing 2.0 micrograms selenium as DL-SeMet with or without the addition of 1.0% methionine. The selenoamino acid content of tissues and the distribution of 75 Se in erythrocyte proteins were determined. In comparison to the rats fed the basal diet without added methionine, significantly more 75 Se-selenocysteine was found in liver and muscle, more 75 Se was found in erythrocyte GSHPx and less 75 Se was found in erythrocyte hemoglobin of rats fed 1.0% methionine. These data suggest that methionine diverts SeMet from incorporation into general proteins and enhances its conversion to selenocysteine for specific selenium-requiring proteins, such as GSHPx

Protection of cisplatin-induced spermatotoxicity, DNA damage and chromatin abnormality by selenium nano-particles

Energy Technology Data Exchange (ETDEWEB)

Rezvanfar, Mohammad Amin; Rezvanfar, Mohammad Ali [Department of Toxicology and Pharmacology, Faculty of Pharmacy, and Pharmaceutical Sciences Research Center, Tehran University of Medical Sciences (TUMS), Tehran (Iran, Islamic Republic of); Shahverdi, Ahmad Reza [Department of Pharmaceutical Biotechnology and Biotechnology Research Centre, Faculty of Pharmacy, TUMS, Tehran (Iran, Islamic Republic of); Ahmadi, Abbas [Department of Histology and Embryology, Faculty of Veterinary Medicine, Urmia University, Urmia (Iran, Islamic Republic of); Baeeri, Maryam; Mohammadirad, Azadeh [Department of Toxicology and Pharmacology, Faculty of Pharmacy, and Pharmaceutical Sciences Research Center, Tehran University of Medical Sciences (TUMS), Tehran (Iran, Islamic Republic of); Abdollahi, Mohammad, E-mail: mohammad.abdollahi@utoronto.ca [Department of Toxicology and Pharmacology, Faculty of Pharmacy, and Pharmaceutical Sciences Research Center, Tehran University of Medical Sciences (TUMS), Tehran (Iran, Islamic Republic of)

2013-02-01

Cisplatin (CIS), an anticancer alkylating agent, induces DNA adducts and effectively cross links the DNA strands and so affects spermatozoa as a male reproductive toxicant. The present study investigated the cellular/biochemical mechanisms underlying possible protective effect of selenium nano-particles (Nano-Se) as an established strong antioxidant with more bioavailability and less toxicity, on reproductive toxicity of CIS by assessment of sperm characteristics, sperm DNA integrity, chromatin quality and spermatogenic disorders. To determine the role of oxidative stress (OS) in the pathogenesis of CIS gonadotoxicity, the level of lipid peroxidation (LPO), antioxidant enzymes including superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) and peroxynitrite (ONOO) as a marker of nitrosative stress (NS) and testosterone (T) concentration as a biomarker of testicular function were measured in the blood and testes. Thirty-two male Wistar rats were equally divided into four groups. A single IP dose of CIS (7 mg/kg) and protective dose of Nano-Se (2 mg/kg/day) were administered alone or in combination. The CIS-exposed rats showed a significant increase in testicular and serum LPO and ONOO level, along with a significant decrease in enzymatic antioxidants levels, diminished serum T concentration and abnormal histologic findings with impaired sperm quality associated with increased DNA damage and decreased chromatin quality. Coadministration of Nano-Se significantly improved the serum T, sperm quality, and spermatogenesis and reduced CIS-induced free radical toxic stress and spermatic DNA damage. In conclusion, the current study demonstrated that Nano-Se may be useful to prevent CIS-induced gonadotoxicity through its antioxidant potential. Highlights: ► Cisplatin (CIS) affects spermatozoa as a male reproductive toxicant. ► Effect of Nano-Se on CIS-induced spermatotoxicity was investigated. ► CIS-exposure induces oxidative sperm DNA damage

Long-term selenium status in humans

International Nuclear Information System (INIS)

Baskett, C.K.; Spate, V.L.; Mason, M.M.; Nichols, T.A.; Williams, A.; Dubman, I.M.; Gudino, A.; Denison, J.; Morris, J.S.

2001-01-01

The association of sub-optimal selenium status with increased risk factors for some cancers has been reported in two recent epidemiological studies. In both studies the same threshold in selenium status was observed, below which, cancer incidence increased. To assess the use of nails as a biologic monitor to measure the long-term selenium status, an eight-year longitudinal study was undertaken with a group of 11 adult subjects, 5 women and 6 men. Selenium has been measured by instrumental neutron activation analysis. Differences between fingernails and toenails with be discussed. In addition, the results will be discussed in the context of the long-term stability of the nail monitor to measure selenium status during those periods when selenium determinants are static; and the changes that occur as a result of selenium supplementation. (author)

Daily rhythms of catalase and glutathione peroxidase expression and activity are endogenously driven in the hippocampus and are modified by a vitamin A-free diet.

Science.gov (United States)

Navigatore-Fonzo, Lorena S; Delgado, Silvia M; Gimenez, Maria Sofia; Anzulovich, Ana C

2014-01-01

Alterations in enzymatic antioxidant defense systems lead to a deficit of cognitive functions and altered hippocampal synaptic plasticity. The objectives of this study were to investigate endogenous rhythms of catalase (CAT) and glutathione peroxidase (GPx) expression and activity, as well as CREB1 mRNA, in the rat hippocampus, and to evaluate to which extent the vitamin A deficiency could affect those temporal patterns. Rats from control and vitamin A-deficient (VAD) groups received a diet containing 4000 IU of vitamin A/kg diet, or the same diet devoid of vitamin A, respectively, during 3 months. Rats were maintained under 12-hour-dark conditions, during 10 days before the sacrifice. Circadian rhythms of CAT, GPx, RXRγ, and CREB1 mRNA levels were determined by reverse transcriptrase polymerase chain reaction in hippocampus samples isolated every 4 hours during a 24-hour period. CAT and GPx enzymatic activities were also determined by kinetic assays. Regulatory regions of clock and antioxidant enzymes genes were scanned for E-box, RXRE, and CRE sites. E-box, RXRE, and CRE sites were found on regulatory regions of GPx and CAT genes, which display a circadian expression in the rat hippocampus. VAD phase shifted CAT, GPx, and RXRγ endogenous rhythms without affecting circadian expression of CREB1. CAT and GPx expression and enzymatic activity are circadian in the rat hippocampus. The VAD affected the temporal patterns antioxidant genes expression, probably by altering circadian rhythms of its RXR receptors and clock factors; thus, it would impair the temporal orchestration of hippocampal daily cognitive performance.

Assessment of oxidative stress and histopathology in juvenile northern pike (Esox lucius) inhabiting lakes downstream of a uranium mill

Energy Technology Data Exchange (ETDEWEB)

Kelly, Jocelyn M. [Toxicology Centre, University of Saskatchewan, 44 Campus Drive, Saskatoon, SK, S7N 5B3 (Canada); Janz, David M., E-mail: david.janz@usask.ca [Toxicology Centre, University of Saskatchewan, 44 Campus Drive, Saskatoon, SK, S7N 5B3 (Canada); Department of Veterinary Biomedical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, 52 Campus Drive, Saskatoon, SK, S7N 5B4 (Canada)

2009-05-17

Lakes receiving effluent from the Key Lake uranium mill in northern Saskatchewan contain elevated trace metals, some of which are associated with increased reactive oxygen species (ROS) in cells and tissues causing oxidative stress. The potential for oxidative stress was assessed in juvenile (age 1+) northern pike (Esox lucius) collected from two exposure (high and low) and one reference lake near the Key Lake operation. The concentrations of total, reduced and oxidized glutathione and the ratio of oxidized to reduced glutathione in liver and kidney did not differ significantly among pike collected from exposure and reference lakes, with the exception of low exposure pike kidney that had significantly greater oxidized glutathione and ratio of oxidized to reduced glutathione. The concentrations of by-products of lipid peroxidation (malondialdehyde and 4-hydroxyalkenal) were significantly greater in kidney of pike collected from the reference lake compared to both exposure lakes. The activity of the antioxidant enzyme glutathione peroxidase in liver was greater in pike collected from the high exposure lake compared to the reference lake. Histopathological evaluations revealed greater pathology in reference lake pike as indicated by a greater number of pyknotic and fragmented nuclei and dilated tubules as well as a thickening of Bowman's capsule in kidney, and as a thickening of the primary filament epithelial padding in gills. In liver, hepatocyte morphology, including transsectional area and degree of vacuolation, differed among lakes without any clear signs of pathology. Trace metal analyses of muscle showed that eight elements (arsenic, cobalt, copper, iron, molybdenum, selenium, thallium, and uranium) were significantly elevated in pike collected from both exposure lakes compared to reference. These results provide only limited evidence of oxidative stress in exposure pike tissues and no evidence of histopathology despite indications that trace metals, most

Assessment of oxidative stress and histopathology in juvenile northern pike (Esox lucius) inhabiting lakes downstream of a uranium mill

International Nuclear Information System (INIS)

Kelly, Jocelyn M.; Janz, David M.

2009-01-01

Lakes receiving effluent from the Key Lake uranium mill in northern Saskatchewan contain elevated trace metals, some of which are associated with increased reactive oxygen species (ROS) in cells and tissues causing oxidative stress. The potential for oxidative stress was assessed in juvenile (age 1+) northern pike (Esox lucius) collected from two exposure (high and low) and one reference lake near the Key Lake operation. The concentrations of total, reduced and oxidized glutathione and the ratio of oxidized to reduced glutathione in liver and kidney did not differ significantly among pike collected from exposure and reference lakes, with the exception of low exposure pike kidney that had significantly greater oxidized glutathione and ratio of oxidized to reduced glutathione. The concentrations of by-products of lipid peroxidation (malondialdehyde and 4-hydroxyalkenal) were significantly greater in kidney of pike collected from the reference lake compared to both exposure lakes. The activity of the antioxidant enzyme glutathione peroxidase in liver was greater in pike collected from the high exposure lake compared to the reference lake. Histopathological evaluations revealed greater pathology in reference lake pike as indicated by a greater number of pyknotic and fragmented nuclei and dilated tubules as well as a thickening of Bowman's capsule in kidney, and as a thickening of the primary filament epithelial padding in gills. In liver, hepatocyte morphology, including transsectional area and degree of vacuolation, differed among lakes without any clear signs of pathology. Trace metal analyses of muscle showed that eight elements (arsenic, cobalt, copper, iron, molybdenum, selenium, thallium, and uranium) were significantly elevated in pike collected from both exposure lakes compared to reference. These results provide only limited evidence of oxidative stress in exposure pike tissues and no evidence of histopathology despite indications that trace metals, most

The study of ascorbate peroxidase, catalase and peroxidase during in vitro regeneration of Argyrolobium roseum.

Science.gov (United States)

Habib, Darima; Chaudhary, Muhammad Fayyaz; Zia, Muhammad

2014-01-01

Here, we demonstrate the micropropagation protocol of Argyrolobium roseum (Camb.), an endangered herb exhibiting anti-diabetic and immune-suppressant properties, and antioxidant enzymes pattern is evaluated. Maximum callogenic response (60 %) was observed from leaf explant at 1.0 mg L(-1) 1-nephthalene acetic acid (NAA) and 0.5 mg L(-1) 6-benzyl aminopurine (BA) in Murashige and Skoog (MS) medium using hypocotyl and root explants (48 % each). Addition of AgNO3 and PVP in the culture medium led to an increase in callogenic response up to 86 % from leaf explant and 72 % from hypocotyl and root explants. The best shooting response was observed in the presence of NAA, while maximum shoot length and number of shoots were achieved based on BA-supplemented MS medium. The regenerated shoots were rooted and successfully acclimatized under greenhouse conditions. Catalase and peroxidase enzymes showed ascending pattern during in vitro plant development from seed while ascorbate peroxidase showed descending pattern. Totally reverse response of these enzymes was observed during callus induction from three different explants. During shoot induction, catalase and peroxidase increased at high rate while there was a mild reduction in ascorbate peroxidase activity. Catalase and peroxidase continuously increased; on the other hand, ascorbate peroxidase activity decreased during root development and acclimatization states. The protocol described here can be employed for the mass propagation and genetic transformation of this rare herb. This study also highlights the importance and role of ascorbate peroxidase, catalase, and peroxidase in the establishment of A. roseum in vitro culture through callogenesis and organogenesis.

Mechanism of Selenium Loss in Copper Slag

Science.gov (United States)

Desai, Bhavin; Tathavadkar, Vilas; Basu, Somnath

2018-03-01

During smelting of copper sulfide concentrate, selenium is distributed between silica-saturated iron-silicate slag and copper-iron sulfide matte. The recovery coefficients of selenium between slag and matte were determined as a function of the initial concentration of selenium at 1523 K (1250 °C) under an inert atmosphere in a vertical tubular furnace. The initial concentration of selenium was varied by the addition of metallic selenium as well as selenium dioxide to the mixture of slag and matte. Analysis of the results indicated high affinity of selenium for matte. The apparent loss of selenium with the slag was attributed to the presence of selenium-enriched matte particles entrapped in the slag, rather than dissolved SeO2. The mechanisms proposed by previous investigators were discussed and also compared with the results of the present investigation.

Mechanism of Selenium Loss in Copper Slag

Science.gov (United States)

Desai, Bhavin; Tathavadkar, Vilas; Basu, Somnath

2018-06-01

During smelting of copper sulfide concentrate, selenium is distributed between silica-saturated iron-silicate slag and copper-iron sulfide matte. The recovery coefficients of selenium between slag and matte were determined as a function of the initial concentration of selenium at 1523 K (1250 °C) under an inert atmosphere in a vertical tubular furnace. The initial concentration of selenium was varied by the addition of metallic selenium as well as selenium dioxide to the mixture of slag and matte. Analysis of the results indicated high affinity of selenium for matte. The apparent loss of selenium with the slag was attributed to the presence of selenium-enriched matte particles entrapped in the slag, rather than dissolved SeO2. The mechanisms proposed by previous investigators were discussed and also compared with the results of the present investigation.

Selenium and Prostate Cancer Prevention: Insights from the Selenium and Vitamin E Cancer Prevention Trial (SELECT)

Science.gov (United States)

Nicastro, Holly L.; Dunn, Barbara K.

2013-01-01

The Selenium and Vitamin E Cancer Prevention Trial (SELECT) was conducted to assess the efficacy of selenium and vitamin E alone, and in combination, on the incidence of prostate cancer. This randomized, double-blind, placebo-controlled, 2 × 2 factorial design clinical trial found that neither selenium nor vitamin E reduced the incidence of prostate cancer after seven years and that vitamin E was associated with a 17% increased risk of prostate cancer compared to placebo. The null result was surprising given the strong preclinical and clinical evidence suggesting chemopreventive activity of selenium. Potential explanations for the null findings include the agent formulation and dose, the characteristics of the cohort, and the study design. It is likely that only specific subpopulations may benefit from selenium supplementation; therefore, future studies should consider the baseline selenium status of the participants, age of the cohort, and genotype of specific selenoproteins, among other characteristics, in order to determine the activity of selenium in cancer prevention. PMID:23552052

Selenium and Prostate Cancer Prevention: Insights from the Selenium and Vitamin E Cancer Prevention Trial (SELECT

Directory of Open Access Journals (Sweden)

Holly L. Nicastro

2013-04-01

Full Text Available The Selenium and Vitamin E Cancer Prevention Trial (SELECT was conducted to assess the efficacy of selenium and vitamin E alone, and in combination, on the incidence of prostate cancer. This randomized, double-blind, placebo-controlled, 2 × 2 factorial design clinical trial found that neither selenium nor vitamin E reduced the incidence of prostate cancer after seven years and that vitamin E was associated with a 17% increased risk of prostate cancer compared to placebo. The null result was surprising given the strong preclinical and clinical evidence suggesting chemopreventive activity of selenium. Potential explanations for the null findings include the agent formulation and dose, the characteristics of the cohort, and the study design. It is likely that only specific subpopulations may benefit from selenium supplementation; therefore, future studies should consider the baseline selenium status of the participants, age of the cohort, and genotype of specific selenoproteins, among other characteristics, in order to determine the activity of selenium in cancer prevention.

Selenium for preventing cancer.

Science.gov (United States)

Vinceti, Marco; Filippini, Tommaso; Del Giovane, Cinzia; Dennert, Gabriele; Zwahlen, Marcel; Brinkman, Maree; Zeegers, Maurice Pa; Horneber, Markus; D'Amico, Roberto; Crespi, Catherine M

2018-01-29

This review is the third update of the Cochrane review "Selenium for preventing cancer". Selenium is a naturally occurring element with both nutritional and toxicological properties. Higher selenium exposure and selenium supplements have been suggested to protect against several types of cancer. To gather and present evidence needed to address two research questions:1. What is the aetiological relationship between selenium exposure and cancer risk in humans?2. Describe the efficacy of selenium supplementation for cancer prevention in humans. We updated electronic searches of the Cochrane Central Register of Controlled Trials (CENTRAL; 2017, Issue 2), MEDLINE (Ovid, 2013 to January 2017, week 4), and Embase (2013 to 2017, week 6), as well as searches of clinical trial registries. We included randomised controlled trials (RCTs) and longitudinal observational studies that enrolled adult participants. We performed random-effects (RE) meta-analyses when two or more RCTs were available for a specific outcome. We conducted RE meta-analyses when five or more observational studies were available for a specific outcome. We assessed risk of bias in RCTs and in observational studies using Cochrane's risk assessment tool and the Newcastle-Ottawa Scale, respectively. We considered in the primary analysis data pooled from RCTs with low risk of bias. We assessed the certainty of evidence by using the GRADE approach. We included 83 studies in this updated review: two additional RCTs (10 in total) and a few additional trial reports for previously included studies. RCTs involved 27,232 participants allocated to either selenium supplements or placebo. For analyses of RCTs with low risk of bias, the summary risk ratio (RR) for any cancer incidence was 1.01 (95% confidence interval (CI) 0.93 to 1.10; 3 studies, 19,475 participants; high-certainty evidence). The RR for estimated cancer mortality was 1.02 (95% CI 0.80 to 1.30; 1 study, 17,444 participants). For the most frequently

Selenium in human mammary carcinogenesis

DEFF Research Database (Denmark)

Overvad, Kim; Grøn, P.; Langhoff, Otto

1991-01-01

/l and TNM stage II 76 +/- 13 micrograms selenium/l), indicating disease-mediated changes. The evaluation of selenium as a risk indicator in human breast cancer was therefore restricted to TNM stage I patients (n = 36). Multiple logistic regression analyses including variables associated with selenium levels...

Genetic association of glutathione peroxidase-1 with coronary artery calcification in type 2 diabetes: a case control study with multi-slice computed tomography

Directory of Open Access Journals (Sweden)

Fujimoto Kei

2007-09-01

Full Text Available Abstract Background Although oxidative stress by accumulation of reactive oxygen species (ROS in diabetes has become evident, it remains unclear what genes, involved in redox balance, would determine susceptibility for development of atherosclerosis in diabetes. This study evaluated the effect of genetic polymorphism of enzymes producing or responsible for reducing ROS on coronary artery calcification in type 2 diabetes (T2D. Methods An index for coronary-arteriosclerosis, coronary artery calcium score (CACS was evaluated in 91 T2D patients using a multi-slice computed tomography. Patients were genotyped for ROS-scavenging enzymes, Glutathione peroxidase-1 (GPx-1, Catalase, Mn-SOD, Cu/Zn-SOD, as well as SNPs of NADPH oxidase as ROS-promoting elements, genes related to onset of T2D (CAPN10, ADRB3, PPAR gamma, FATP4. Age, blood pressure, BMI, HbA1c, lipid and duration of diabetes were evaluated for a multivariate regression analysis. Results CACS with Pro/Leu genotype of the GPx-1 gene was significantly higher than in those with Pro/Pro (744 ± 1,291 vs. 245 ± 399, respectively, p = 0.006. In addition, genotype frequency of Pro/Leu in those with CACS ≥ 1000 was significantly higher than in those with CACS OR = 3.61, CI = 0.97–13.42; p = 0.045 when tested for deviation from Hardy-Weinberg's equilibrium. Multivariate regression analyses revealed that CACS significantly correlated with GPx-1 genotypes and age. Conclusion The presence of Pro197Leu substitution of the GPx-1 gene may play a crucial role in determining genetic susceptibility to coronary-arteriosclerosis in T2D. The mechanism may be associated with a decreased ability to scavenge ROS with the variant GPx-1.

Mercury species, selenium, metallothioneins and glutathione in two dolphins from the southeastern Brazilian coast: Mercury detoxification and physiological differences in diving capacity

International Nuclear Information System (INIS)

Kehrig, Helena A.; Hauser-Davis, Rachel A.; Seixas, Tercia G.; Pinheiro, Ana Beatriz; Di Beneditto, Ana Paula M.

2016-01-01

In the present study, the concentration of trace elements, total mercury (Hg) and selenium (Se) and mercury forms (MeHg, Hg inorg and HgSe) in the vulnerable coastal dolphins Pontoporia blainvillei and Sotalia guianensis were appraised and compared, using metallothioneins (MT) and glutathione (GSH) as biomarkers for trace element exposure. The trace element concentrations varied between muscle and liver tissues, with liver of all dolphin specimens showing higher Hg and Se concentrations than those found in muscle. Hg, MeHg and Hg inorg molar concentrations showed a clear increase with Se molar concentrations in the liver of both dolphins, and Se concentrations were higher than those of Hg on a molar basis. Se plays a relevant role in the detoxification of MeHg in the hepatic tissue of both dolphins, forming Hg-Se amorphous crystals in liver. In contrast, MT were involved in the detoxification process of Hg inorg in liver. GSH levels in P. blainvillei and S. guianensis muscle tissue suggest that these dolphins have different diving capacities. Muscle Hg concentrations were associated to this tripeptide, which protects dolphin cells against Hg stress. - Highlights: • Se aids in MeHg detoxification in dolphin liver, forming Hg-Se amorphous crystals. • MT was involved in liver Hg inorg detoxification and GSH was associated to muscle Hg. • Feeding habits seem to influence muscle GSH, suggesting different diving capacities. • MT, GSH and Se and Hg in different forms were investigated in two dolphin species. • Hepatic Hg, MeHg and Hg inorg increased with higher Se concentrations. - “Coastal dolphins showed Se-mediated detoxification of MeHg and MT-mediated detoxification of Hg inorg , while GSH suggests different diving capacities”.

Purification, molecular cloning and heterologous expression of a glutathione S-transferase involved in insecticide resistance from the rice brown planthopper, Nilaparvata lugens.

OpenAIRE

Vontas, John G; Small, Graham J; Nikou, Dimitra C; Ranson, Hilary; Hemingway, Janet

2002-01-01

A novel glutathione S-transferase (GST)-based pyrethroid resistance mechanism was recently identified in Nilaparvata lugens [Vontas, Small and Hemingway (2001) Biochem. J. 357, 65-72]. To determine the nature of GSTs involved in conferring this resistance, the GSTs from resistant and susceptible strains of N. lugens were partially purified by anion exchange and affinity chromatography. The majority of peroxidase activity, previously correlated with resistance, was confined to the fraction tha...

Selenium deficiency inhibits the conversion of thyroidal thyroxine (T4) to triiodothyronine (T3) in chicken thyroids.

Science.gov (United States)

Lin, Shi-lei; Wang, Cong-wu; Tan, Si-ran; Liang, Yang; Yao, Hai-dong; Zhang, Zi-wei; Xu, Shi-wen

2014-12-01

Selenium (Se) influences the metabolism of thyroid hormones in mammals. However, the role of Se deficiency in the regulation of thyroid hormones in chickens is not well known. In the present study, we examined the levels of thyroidal triiodothyronine (T3), thyroidal thyroxine (T4), free triiodothyronine, free thyroxine (FT4), and thyroid-stimulating hormone in the serum and the mRNA expression levels of 25 selenoproteins in chicken thyroids. Then, principal component analysis (PCA) was performed to analyze the relationships between the selenoproteins. The results indicated that Se deficiency influenced the conversion of T4 to T3 and induced the accumulation of T4 and FT4. In addition, the mRNA expression levels of the selenoproteins were generally decreased by Se deficiency. The PCA showed that eight selenoproteins (deiodinase 1 (Dio1), Dio2, Dio3, thioredoxin reductase 2 (Txnrd2), selenoprotein i (Seli), selenoprotein u (Selu), glutathione peroxidase 1 (Gpx1), and Gpx2) have similar trends, which indicated that they may play similar roles in the metabolism of thyroid hormones. The results showed that Se deficiency inhibited the conversion of T4 to T3 and decreased the levels of the crucial metabolic enzymes of the thyroid hormones, Dio1, Dio2, and Dio3, in chickens. In addition, the decreased selenoproteins (Dio1, Dio2, Dio3, Txnrd2, Seli, Selu, Gpx1, and Gpx2) induced by Se deficiency may indirectly limit the conversion of T4 to T3 in chicken thyroids. The information presented in this study is helpful to understand the role of Se in the thyroid function of chickens.

Selenium in food and health

National Research Council Canada - National Science Library

Reilly, Conor

2006-01-01

...) to be a carcinogen and banned as an additive in food. Selenium is considered by some to be a serious hazard to the environment and to animal health. Selenium-contaminated water has brought deformity and death to wildlife in nature reserves in western USA. There is even concern that because of selenium contamination of soil, crops supplied to the great cities of California could become unfit for human consumption. In large areas of China, endemic selenium toxicity is a hazard for locals who depend on cr...

Expression Patterns of Genes Involved in Ascorbate-Glutathione Cycle in Aphid-Infested Maize (Zea mays L.) Seedlings.

Science.gov (United States)

Sytykiewicz, Hubert

2016-02-23

Reduced forms of ascorbate (AsA) and glutathione (GSH) are among the most important non-enzymatic foliar antioxidants in maize (Zea mays L.). The survey was aimed to evaluate impact of bird cherry-oat aphid (Rhopalosiphum padi L.) or grain aphid (Sitobion avenae F.) herbivory on expression of genes related to ascorbate-glutathione (AsA-GSH) cycle in seedlings of six maize varieties (Ambrozja, Nana, Tasty Sweet, Touran, Waza, Złota Karłowa), differing in resistance to the cereal aphids. Relative expression of sixteen maize genes encoding isoenzymes of ascorbate peroxidase (APX1, APX2, APX3, APX4, APX5, APX6, APX7), monodehydroascorbate reductase (MDHAR1, MDHAR2, MDHAR3, MDHAR4), dehydroascorbate reductase (DHAR1, DHAR2, DHAR3) and glutathione reductase (GR1, GR2) was quantified. Furthermore, effect of hemipterans' attack on activity of APX, MDHAR, DHAR and GR enzymes, and the content of reduced and oxidized ascorbate and glutathione in maize plants were assessed. Seedling leaves of more resistant Z. mays varieties responded higher elevations in abundance of target transcripts. In addition, earlier and stronger aphid-triggered changes in activity of APX, MDHAR, DHAR and GR enzymes, and greater modulations in amount of the analyzed antioxidative metabolites were detected in foliar tissues of highly resistant Ambrozja genotype in relation to susceptible Tasty Sweet plants.

Impaired synthesis and antioxidant defense of glutathione in the cerebellum of autistic subjects: alterations in the activities and protein expression of glutathione-related enzymes.

Science.gov (United States)

Gu, Feng; Chauhan, Ved; Chauhan, Abha

2013-12-01

Autism is a neurodevelopmental disorder associated with social deficits and behavioral abnormalities. Recent evidence in autism suggests a deficit in glutathione (GSH), a major endogenous antioxidant. It is not known whether the synthesis, consumption, and/or regeneration of GSH is affected in autism. In the cerebellum tissues from autism (n=10) and age-matched control subjects (n=10), the activities of GSH-related enzymes glutathione peroxidase (GPx), glutathione-S-transferase (GST), glutathione reductase (GR), and glutamate cysteine ligase (GCL) involved in antioxidant defense, detoxification, GSH regeneration, and synthesis, respectively, were analyzed. GCL is a rate-limiting enzyme for GSH synthesis, and the relationship between its activity and the protein expression of its catalytic subunit GCLC and its modulatory subunit GCLM was also compared between the autistic and the control groups. Results showed that the activities of GPx and GST were significantly decreased in autism compared to that of the control group (Pautistic subjects showed lower GR activity than 95% confidence interval (CI) of the control group. GCL activity was also significantly reduced by 38.7% in the autistic group compared to the control group (P=0.023), and 8 of 10 autistic subjects had values below 95% CI of the control group. The ratio of protein levels of GCLC to GCLM in the autism group was significantly higher than that of the control group (P=0.022), and GCLM protein levels were reduced by 37.3% in the autistic group compared to the control group. A positive strong correlation was observed between GCL activity and protein levels of GCLM (r=0.887) and GCLC (r=0.799) subunits in control subjects but not in autistic subjects, suggesting that regulation of GCL activity is affected in autism. These results suggest that enzymes involved in GSH homeostasis have impaired activities in the cerebellum in autism, and lower GCL activity in autism may be related to decreased protein expression

Speciation of selenium dietary supplements; formation of S-(methylseleno)cysteine and other selenium compounds

International Nuclear Information System (INIS)

Amoako, Prince O.; Uden, Peter C.; Tyson, Julian F.

2009-01-01

Speciation of selenium is of interest because it is both essential and toxic to humans, depending on the species and the amount ingested. Following indications that selenium supplementation could reduce the incidence of some cancers, selenium-enriched yeast and other materials have been commercialized as supplements. Most dramatically however, the SELECT trial that utilized L-selenomethionine as the active supplement was terminated in 2008 and there is much debate regarding both the planning and the results of efficacy studies. Further, since dietary supplements are not regulated as pharmaceuticals, there are concerns about the quality, storage conditions, stability and selenium content in selenium supplements. Enzymatic hydrolysis enabled selenium speciation profiles to be obtained by high performance liquid chromatography with inductively coupled plasma mass spectrometry (HPLC-ICP-MS) and following derivatization gas chromatography with atomic emission detection (GC-AED). Coated fiber solid phase microextraction (SPME) was used to extract volatile selenium species for determination by GC-AED and GC-MS. Similar speciation patterns were observed between yeast-based supplements subject to extended storage and those heated briefly at elevated temperatures. All the yeast-based supplements and one yeast-free supplement formed S-(methylseleno)cysteine on heating. Evidence was obtained in support of the hypotheses that S-(methylseleno)cysteine is formed from a reaction between dimethyldiselenide and cysteine or cystine.

Antiinflammatory effects of Cordia myxa fruit on experimentally induced colitis in rats.

Science.gov (United States)

Al-Awadi, F M; Srikumar, T S; Anim, J T; Khan, I

2001-05-01

Products of certain species of Cordia are reported to have antiinflammatory properties. In the present study we examined the effects of Cordia myxa fruit on experimentally induced colitis in rats. Colitis was induced by intrarectal administration of 4% acetic acid. Colitic, normal, and corresponding control animals were included. Body weight was recorded daily. All the animals were sacrificed 4 days after the fruit treatment. Colitis was monitored histologically and by activity of myeloperoxidase. Glutathione peroxidase, superoxide dismutase, as well as total antioxidant status and concentrations of zinc, copper, manganese, selenium, and iron were assayed in plasma, liver, and colon using standard methods. Histology of the colon of colitic rats showed acute colitis that was confirmed by a significant increase in the myeloperoxidase activity. Colitis was associated with significant decreases in the tissue activities of glutathione peroxidase and superoxide dismutase and lower concentrations of trace elements. Histologic examination and myeloperoxidase activity showed that the fruit treatment reversed the above findings in the inflamed colon, and in liver and plasma of colitic rats. The present results suggest that the observed antiinflammatory effect of the Cordia myxa may be attributed partly to its antioxidant property and to restoration of the levels of trace elements in the inflamed colon, liver, and plasma.

Selenium for preventing cancer

Science.gov (United States)

Vinceti, Marco; Dennert, Gabriele; Crespi, Catherine M; Zwahlen, Marcel; Brinkman, Maree; Zeegers, Maurice PA; Horneber, Markus; D'Amico, Roberto; Del Giovane, Cinzia

2015-01-01

Background This review is an update of the first Cochrane publication on selenium for preventing cancer (Dennert 2011). Selenium is a metalloid with both nutritional and toxicological properties. Higher selenium exposure and selenium supplements have been suggested to protect against several types of cancers. Objectives Two research questions were addressed in this review: What is the evidence for: an aetiological relation between selenium exposure and cancer risk in humans? andthe efficacy of selenium supplementation for cancer prevention in humans? Search methods We conducted electronic searches of the Cochrane Central Register of Controlled Trials (CENTRAL, 2013, Issue 1), MEDLINE (Ovid, 1966 to February 2013 week 1), EMBASE (1980 to 2013 week 6), CancerLit (February 2004) and CCMed (February 2011). As MEDLINE now includes the journals indexed in CancerLit, no further searches were conducted in this database after 2004. Selection criteria We included prospective observational studies (cohort studies including sub-cohort controlled studies and nested case-control studies) and randomised controlled trials (RCTs) with healthy adult participants (18 years of age and older). Data collection and analysis For observational studies, we conducted random effects meta-analyses when five or more studies were retrieved for a specific outcome. For RCTs, we performed random effects meta-analyses when two or more studies were available. The risk of bias in observational studies was assessed using forms adapted from the Newcastle-Ottawa Quality Assessment Scale for cohort and case-control studies; the criteria specified in the Cochrane Handbook for Systematic Reviews of Interventions were used to evaluate the risk of bias in RCTs. Main results We included 55 prospective observational studies (including more than 1,100,000 participants) and eight RCTs (with a total of 44,743 participants). For the observational studies, we found lower cancer incidence (summary odds ratio (OR) 0

21 CFR 573.920 - Selenium.

Science.gov (United States)

2010-04-01

... section, or as selenium yeast, as provided in paragraph (h) of this section. (c) It is added to feed as... months.” (h) Selenium yeast is a dried, non-viable yeast (Saccharomyces cerevisiae) cultivated in a fed-batch fermentation which provides incremental amounts of cane molasses and selenium salts in a manner...

Dietary selenium in the Glasgow area

International Nuclear Information System (INIS)

Cross, J.D.; Raie, R.M.; Smith, H.

1978-01-01

A typical diet for people in the Glasgow area is analysed and an estimate is made of the daily intake of selenium for the average person (234 μg). Meat, poultry and bread products contribute 65% of the total selenium consumed. There is a significant loss of selenium on cooking but the concentration in the diet is high compared with the estimated requirement. Selenium levels in prepared infant foods, artificial milk and natural milk are reported. Those infants on artificial milk feeds have a selenium intake equivalent to that of adults (3 μg/kg) while those on natural milk or prepared infant foods have an intake of 6 μg/kg. Adult and infant tissue selenium levels are established and are shown to be in equilibrium with the diet. There is no concentration in man as a result of his position at the top of the food chain. Sudden infant death cannot be related to selenium levels in human tissue or diet. (author)

Glutathione peroxidase-1 gene (GPX1) variants, oxidative stress and risk of kidney complications in people with type 1 diabetes.

Science.gov (United States)

Mohammedi, Kamel; Patente, Thiago A; Bellili-Muñoz, Naima; Driss, Fathi; Le Nagard, Hervé; Fumeron, Frédéric; Roussel, Ronan; Hadjadj, Samy; Corrêa-Giannella, Maria Lúcia; Marre, Michel; Velho, Gilberto

2016-02-01

Glutathione peroxidase (GPX) is a class of antioxidant enzymes that catalyze the reduction of hydrogen peroxide to water. GPX1 is the most abundant isoform and is expressed in all kidney cells. Isoprostane and advanced oxidation protein products (AOPP) were identified as markers of oxidative stress in patients with kidney disease. We investigated associations of GPX1 genotypes with kidney complications, and with plasma concentrations of isoprostane and AOPP in type 1 diabetic patients. Four SNPs in the GPX1 gene region were genotyped in SURGENE (n=340; 10-year follow-up); GENEDIAB (n=461) and GENESIS (n=584) cohorts of type 1 diabetic patients. Subsets of GENEDIAB (n=237) and GENESIS (n=466) participants were followed up for 9 and 5years, respectively. Plasma concentrations of isoprostane and AOPP were measured at baseline in GENEDIAB. Hazard ratios (HR) were estimated for incidence of kidney complications. In SURGENE, 98 renal events (new cases of microalbuminuria or progression to more severe stage of diabetic nephropathy) occurred during follow-up. The minor T-allele of rs3448 was associated with the incidence of renal events (HR 1.81, 95% CI 1.16-2.84, p=0.008). In GENESIS/GENEDIAB pooled study, end stage renal disease (ESRD) occurred during follow-up in 52 individuals. The same variant was associated with the incidence of ESRD (HR 3.34, 95% CI, 1.69-6.98, p=0.0004). The variant was also associated with higher plasma isoprostane concentration in GENEDIAB cohort: 2.02±0.12 (TT+CT) vs 1.75±0.13 (CC) ng/mL (p=0.009), and with higher plasma AOPP in the subset of participants with the baseline history of ESRD (TT+CT 67±6 vs CC 48±6μmol/L, p=0.006). The minor T-allele of rs3448 was associated with kidney complications (incidences of microalbuminuria, renal events and ESRD) in patients with type 1 diabetes. The risk allele was associated with higher plasma concentrations of isoprostane and AOPP. Our results are consistent with the implication of GPX1 in the

Effects of Gram-negative Bacteria, E.coli and Cold Exposure on Free Radicals Production, Lactate Dehydrogenase and Glutathione Peroxidase Activity in the Lungs of Rats, Rattus norvigicus

International Nuclear Information System (INIS)

AlSaid, A Haffor

2007-01-01

The purpose of this study was to explore the effects of LPS-gram negative bacteria and low ambient temperature on free radicals (FR) production, the activities of lactate dehydrogenase (LDH) and glutathione peroxidase (GPx) in the lungs of rats, Rattus norvigisu. Twenty four male rats, matched with age and weigh, were divided randomly into four groups namely control (C), Bacteria (B), cold temperature (T), and bacteria plus cold (BT). The T group was exposed to 10-12degree C ambient temperature for 3 days. Animals of the BT was injected LPS bacteria (IP, 500 micron g/kg) during the last five hour of cold exposure to 10-12 degree C for 3 days. In comparison with C group FR increased significantly (p<0.05) in the experimental groups, indicating high rate of reactive oxygen species (ROS) accumulation. The activity of LDH increased significantly (p<0.05) in the T and BT groups, which demonstrated that bacteria and exposure to cold are causes for cellular injury in the lungs. The synergetic effect of both bacteria and cold on LDH was more intense, as compared with the single effect. The activity of GPx increased significantly (p<0.05) in the B and BT, as compared with the C group. The results of the present study is the first worldwide report to demonstrate that both cold exposure and bacteria infection are mediated by elevation in FR generation. (author)

Selenium: environmental significance, pollution, and biological treatment technologies.

Science.gov (United States)

Tan, Lea Chua; Nancharaiah, Yarlagadda V; van Hullebusch, Eric D; Lens, Piet N L

2016-01-01

Selenium is an essential trace element needed for all living organisms. Despite its essentiality, selenium is a potential toxic element to natural ecosystems due to its bioaccumulation potential. Though selenium is found naturally in the earth's crust, especially in carbonate rocks and volcanic and sedimentary soils, about 40% of the selenium emissions to atmospheric and aquatic environments are caused by various industrial activities such as mining-related operations. In recent years, advances in water quality and pollution monitoring have shown that selenium is a contaminant of potential environmental concern. This has practical implications on industry to achieve the stringent selenium regulatory discharge limit of 5μgSeL(-1) for selenium containing wastewaters set by the United States Environmental Protection Agency. Over the last few decades, various technologies have been developed for the treatment of selenium-containing wastewaters. Biological selenium reduction has emerged as the leading technology for removing selenium from wastewaters since it offers a cheaper alternative compared to physico-chemical treatments and is suitable for treating dilute and variable selenium-laden wastewaters. Moreover, biological treatment has the advantage of forming elemental selenium nanospheres which exhibit unique optical and spectral properties for various industrial applications, i.e. medical, electrical, and manufacturing processes. However, despite the advances in biotechnology employing selenium reduction, there are still several challenges, particularly in achieving stringent discharge limits, the long-term stability of biogenic selenium and predicting the fate of bioreduced selenium in the environment. This review highlights the significance of selenium in the environment, health, and industry and biotechnological advances made in the treatment of selenium contaminated wastewaters. The challenges and future perspectives are overviewed considering recent

Glutathione transferase-mediated benzimidazole-resistance in Fusarium graminearum.

Science.gov (United States)

Sevastos, A; Labrou, N E; Flouri, F; Malandrakis, A

2017-09-01

Fusarium graminearum laboratory mutants moderately (MR) and highly (HR) benzimidazole-resistant, carrying or not target-site mutations at the β 2 -tubulin gene were utilized in an attempt to elucidate the biochemical mechanism(s) underlying the unique BZM-resistance paradigm of this fungal plant pathogen. Relative expression analysis in the presence or absence of carbendazim (methyl-2-benzimidazole carbamate) using a quantitative Real Time qPCR (RT-qPCR) revealed differences between resistant and the wild-type parental strain although no differences in expression levels of either β 1 - or β 2 -tubulin homologue genes were able to fully account for two of the highly resistant phenotypes. Glutathione transferase (GST)-mediated detoxification was shown to be -at least partly- responsible for the elevated resistance levels of a HR isolate bearing the β 2 -tubulin Phe200Tyr resistance mutation compared with another MR isolate carrying the same mutation. This benzimidazole-resistance mechanism is reported for the first time in F. graminearum. No indications of detoxification involved in benzimidazole resistance were found for the rest of the isolates as revealed by GST and glutathione peroxidase (GPx) activities and bioassays using monoxygenase and hydrolase detoxification enzyme inhibiting synergists. Interestingly, besides the Phe200Tyr mutation-carrying HR isolate, the remaining highly-carbendazim resistant phenotypes could not be associated with any of the target site modification/overproduction, detoxification or reduced uptake-increased efflux mechanisms. Copyright © 2016 Elsevier B.V. All rights reserved.

Protective effects of novel organic selenium compounds against oxidative stress in the nematode Caenorhabditis elegans

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Sílvio Terra Stefanello

2015-01-01

Full Text Available Organic selenium compounds possess numerous biological properties, including antioxidant activity. Yet, the high toxicity of some of them, such as diphenyl diselenide (DPDS, is a limiting factor in their current usage. Accordingly, we tested four novel organic selenium compounds in the non-parasite nematode Caenorhabditis elegans and compared their efficacy to DPDS. The novel organic selenium compounds are β-selenoamines 1-phenyl-3-(p-tolylselanylpropan-2-amine (C1 and 1-(2-methoxyphenylselanyl-3-phenylpropan-2-amine (C2 and analogs of DPDS 1,2-bis(2-methoxyphenyldiselenide (C3 and 1,2-bisp-tolyldiselenide (C4. Synchronized worms at the L4 larval stage were exposed for one hour in M9 buffer to these compounds. Oxidative stress conditions were induced by juglone (200 μM and heat shock (35 °C. Moreover, we evaluated C. elegans behavior, GST-4::GFP (glutathione S-transferase expression and the activity of acetylcholinesterase (AChE. All tested compounds efficiently restored viability in juglone stressed worms. However, DPDS, C2, C3 and C4 significantly decreased the defecation cycle time. Juglone-induced GST-4::GFP expression was not attenuated in worms pretreated with the novel compounds, except with C2. Finally, AChE activity was reduced by DPDS, C2, C3 and C4. To our knowledge, this is study firstly showed the effects of C1, C2, C3 and C4 selenium-derived compounds in C. elegans. Low toxic effects were noted, except for reduction in the defecation cycle, which is likely associated with AChE inhibition. The juglone-induced stress (reduced viability was fully reversed by compounds to control animal levels. C2 was also efficient in reducing the juglone-induced GST-4::GFP expression, suggesting the latter may mediate the stress induced by this compound. Future studies could be profitably directed at addressing additional molecular mechanisms that mediate the protective effects of these novel organic selenium compounds.

Aquatic Life Criterion - Selenium

Science.gov (United States)

Documents pertaining to the 2016 Acute and Chronic Ambient Aquatic Life Water Quality Criteria for Selenium (Freshwater). These documents include what the safe levels of Selenium are in water for the majority of species.

Dependency of a therapy-resistant state of cancer cells on a lipid peroxidase pathway.

Science.gov (United States)

Viswanathan, Vasanthi S; Ryan, Matthew J; Dhruv, Harshil D; Gill, Shubhroz; Eichhoff, Ossia M; Seashore-Ludlow, Brinton; Kaffenberger, Samuel D; Eaton, John K; Shimada, Kenichi; Aguirre, Andrew J; Viswanathan, Srinivas R; Chattopadhyay, Shrikanta; Tamayo, Pablo; Yang, Wan Seok; Rees, Matthew G; Chen, Sixun; Boskovic, Zarko V; Javaid, Sarah; Huang, Cherrie; Wu, Xiaoyun; Tseng, Yuen-Yi; Roider, Elisabeth M; Gao, Dong; Cleary, James M; Wolpin, Brian M; Mesirov, Jill P; Haber, Daniel A; Engelman, Jeffrey A; Boehm, Jesse S; Kotz, Joanne D; Hon, Cindy S; Chen, Yu; Hahn, William C; Levesque, Mitchell P; Doench, John G; Berens, Michael E; Shamji, Alykhan F; Clemons, Paul A; Stockwell, Brent R; Schreiber, Stuart L

2017-07-27

Plasticity of the cell state has been proposed to drive resistance to multiple classes of cancer therapies, thereby limiting their effectiveness. A high-mesenchymal cell state observed in human tumours and cancer cell lines has been associated with resistance to multiple treatment modalities across diverse cancer lineages, but the mechanistic underpinning for this state has remained incompletely understood. Here we molecularly characterize this therapy-resistant high-mesenchymal cell state in human cancer cell lines and organoids and show that it depends on a druggable lipid-peroxidase pathway that protects against ferroptosis, a non-apoptotic form of cell death induced by the build-up of toxic lipid peroxides. We show that this cell state is characterized by activity of enzymes that promote the synthesis of polyunsaturated lipids. These lipids are the substrates for lipid peroxidation by lipoxygenase enzymes. This lipid metabolism creates a dependency on pathways converging on the phospholipid glutathione peroxidase (GPX4), a selenocysteine-containing enzyme that dissipates lipid peroxides and thereby prevents the iron-mediated reactions of peroxides that induce ferroptotic cell death. Dependency on GPX4 was found to exist across diverse therapy-resistant states characterized by high expression of ZEB1, including epithelial-mesenchymal transition in epithelial-derived carcinomas, TGFβ-mediated therapy-resistance in melanoma, treatment-induced neuroendocrine transdifferentiation in prostate cancer, and sarcomas, which are fixed in a mesenchymal state owing to their cells of origin. We identify vulnerability to ferroptic cell death induced by inhibition of a lipid peroxidase pathway as a feature of therapy-resistant cancer cells across diverse mesenchymal cell-state contexts.

Effects of methylmercury exposure on glutathione metabolism, oxidative stress, and chromosomal damage in captive-reared common loon (Gavia immer) chicks

Energy Technology Data Exchange (ETDEWEB)

Kenow, Kevin P. [U.S. Geological Survey, Upper Midwest Environmental Sciences Center, 2630 Fanta Reed Road, La Crosse, WI 54603 (United States)], E-mail: kkenow@usgs.gov; Hoffman, David J. [U.S. Geological Survey, Patuxent Wildlife Research Center, 10300 Baltimore Avenue, Beltsville, MD 20705 (United States)], E-mail: djhoffman@usgs.gov; Hines, Randy K. [U.S. Geological Survey, Upper Midwest Environmental Sciences Center, 2630 Fanta Reed Road, La Crosse, WI 54603 (United States)], E-mail: rkhines@usgs.gov; Meyer, Michael W. [Wisconsin Department of Natural Resources, 107 Sutliff Avenue, Rhinelander, WI 54501 (United States)], E-mail: michael.meyer@dnr.state.wi.us; Bickham, John W. [Center for the Environment and Department of Forestry and Natural Resources, Purdue University, West Lafayette, IN 47907 (United States)], E-mail: bickham@purdue.edu; Matson, Cole W. [Integrated Toxicology and Environmental Health Program, Duke University, Durham, NC 27708 (United States)], E-mail: matson@duke.edu; Stebbins, Katie R. [U.S. Geological Survey, Patuxent Wildlife Research Center, 10300 Baltimore Avenue, Beltsville, MD 20705 (United States); Montagna, Paul [Texas A and M University-Corpus Christi, Harte Research Institute, Corpus Christi, TX (United States)], E-mail: paul.montagna@tamucc.edu; Elfessi, Abdulaziz [University of Wisconsin-La Crosse, La Crosse, WI 54601 (United States)], E-mail: elfessi.abdu@uwlax.edu

2008-12-15

We quantified the level of dietary mercury (Hg), delivered as methylmercury chloride (CH{sub 3}HgCl), associated with negative effects on organ and plasma biochemistries related to glutathione (GSH) metabolism and oxidative stress, and chromosomal damage in captive-reared common loon (Gavia immer) chicks reared from hatch to 105 days. Mercury-associated effects related to oxidative stress and altered glutathione metabolism occurred at 1.2 {mu}g Hg/g and 0.4 {mu}g Hg/g, an ecologically relevant dietary mercury level, but not at 0.08 {mu}g Hg/g. Among the variables that contributed most to dissimilarities in tissue chemistries between control and treatment groups were increased levels of oxidized glutathione (GSSG), GSH peroxidase, and the ratio of GSSG to GSH in brain tissue; increased levels of hepatic GSH; and decreased levels of hepatic glucose-6-phosphate dehydrogenase (G-6-PDH). Our results also suggest that chronic exposure to environmentally relevant dietary Hg levels did not result in statistically significant somatic chromosomal damage in common loon chicks. - Oxidative stress and altered glutathione metabolism were evident in common loon chicks exposed to {>=}0.4 {mu}g Hg as CH{sub 3}HgCl per gram wet food intake.

Wound-induced expression of horseradish peroxidase.

Science.gov (United States)

Kawaoka, A; Kawamoto, T; Ohta, H; Sekine, M; Takano, M; Shinmyo, A

1994-01-01

Peroxidases have been implicated in the responses of plants to physiological stress and to pathogens. Wound-induced peroxidase of horseradish (Armoracia rusticana) was studied. Total peroxidase activity was increased by wounding in cell wall fractions extracted from roots, stems and leaves of horseradish. On the other hand, wounding decreased the peroxidase activity in the soluble fraction from roots. The enzyme activities of the basic isozymes were induced by wounding in horseradish leaves based on data obtained by fractionation of crude enzyme in isoelectric focusing gel electrophoresis followed by activity staining. We have previously isolated genomic clones for four peroxidase genes, namely, prxC1a, prxC1b, prxC2 and prxC3. Northern blot analysis using gene-specific probes showed that mRNA of prxC2, which encodes a basic isozyme, accumulated by wounding, while the mRNAs for other peroxidase genes were not induced. Tobacco (Nicotiana tabacum) plants were transformed with four chimeric gene constructs, each consisting of a promoter from one of the peroxidase genes and the β-glucuronidase (GUS) structural gene. High level GUS activity induced in response to wounding was observed in tobacco plants containing the prxC2-GUS construct.

The glutathione cycle: Glutathione metabolism beyond the γ-glutamyl cycle.

Science.gov (United States)

Bachhawat, Anand Kumar; Yadav, Shambhu

2018-04-17

Glutathione was discovered in 1888, over 125 years ago. Since then, our understanding of various functions and metabolism of this important molecule has grown over these years. But it is only now, in the last decade, that a somewhat complete picture of its metabolism has emerged. Glutathione metabolism has till now been largely depicted and understood by the γ-glutamyl cycle that was proposed in 1970. However, new findings and knowledge particularly on the transport and degradation of glutathione have revealed that many aspects of the γ-glutamyl cycle are incorrect. Despite this, an integrated critical analysis of the cycle has never been undertaken and this has led to the cycle and its errors perpetuating in the literature. This review takes a careful look at the γ-glutamyl cycle and its shortcomings and presents a "glutathione cycle" that captures the current understanding of glutathione metabolism. © 2018 IUBMB Life, 2018. © 2018 International Union of Biochemistry and Molecular Biology.

Selenium in Graves' disease

Directory of Open Access Journals (Sweden)

Jadwiga Kryczyk

2013-05-01

Full Text Available The aim of this study was to present the current state of knowledge of the role of selenium in Graves’ disease. Recently, in the pathogenesis and course of this autoimmune disease, more attention has been paid to the relationship between oxidative stress and the antioxidant system, where selenium compounds play an important role. The thyroid is the organ with the highest selenium concentration in the human body. Selenium compounds, having antioxidant properties, protect thyrocytes against the destructive effects of reactive oxygen species (ROS, which are generated during the synthesis of thyroid hormones. Therefore, strengthening the body’s defense mechanisms, which protect against the formation and activity of ROS during medical treatment of Graves’ disease patients, may be an effective adjuvant in commonly used methods of therapy.

Expression of an enzymatically active Yb3 glutathione S-transferase in Escherichia coli and identification of its natural form in rat brain.

Science.gov (United States)

Abramovitz, M; Ishigaki, S; Felix, A M; Listowsky, I

1988-11-25

Glutathione S-transferases containing Yb3 subunits are relatively uncommon forms that are expressed in a tissue-specific manner and have not been identified unequivocally or characterized. A cDNA clone containing the entire coding sequence of Yb3 glutathione S-transferase mRNA was incorporated into a pIN-III expression vector used to transform Escherichia coli. A fusion Yb3-protein containing 14 additional amino acid residues at its N terminus was purified to homogeneity. Recombinant Yb3 was enzymatically active with both 1-chloro-2,4-dinitrobenzene and 1,2-dichloro-4-nitrobenzene as substrates but lacked glutathione peroxidase activity. Substrate specificity patterns of recombinant Yb3 were more limited than those of glutathione S-transferase isoenzymes containing Yb1- or Yb2-type subunits. Peptides corresponding to unique amino acid sequences of Yb3 as well as a peptide from a region of homology with Yb1 and Yb2 subunits were synthesized. These synthetic peptides were used to raise antibodies specific to Yb3 and others that cross-reacted with all Yb forms. Immunoblotting was utilized to identify the natural counterpart of recombinant Yb3 among rat glutathione transferases. Brain and testis glutathione S-transferases were rich in Yb3 subunits, but very little was found in liver or kidney. Physical properties, substrate specificities, and binding patterns of the recombinant protein paralleled properties of the natural isoenzyme isolated from brain.

Expression of inactive glutathione peroxidase 4 leads to embryonic lethality, and inactivation of the Alox15 gene does not rescue such knock-in mice.

Science.gov (United States)

Brütsch, Simone Hanna; Wang, Chi Chiu; Li, Lu; Stender, Hannelore; Neziroglu, Nilgün; Richter, Constanze; Kuhn, Hartmut; Borchert, Astrid

2015-02-01

Glutathione peroxidases (Gpx) and lipoxygenases (Alox) are functional counterplayers in the metabolism of hydroperoxy lipids that regulate cellular redox homeostasis. Gpx4 is a moonlighting protein that has been implicated not only as an enzyme in anti-oxidative defense, gene expression regulation, and programmed cell death, but also as a structural protein in spermatogenesis. Homozygous Gpx4 knock-out mice are not viable, but molecular reasons for intrauterine lethality are not completely understood. This study was aimed at investigating whether the lack of catalytic activity or the impaired function as structural protein is the dominant reason for embryonic lethality. We further explored whether the pro-oxidative enzyme mouse 12/15 lipoxygenase (Alox15) plays a major role in embryonic lethality of Gpx4-deficient mice. To achieve these goals, we first created knock-in mice, which express a catalytically inactive Gpx4 mutant (Sec46Ala). As homozygous Gpx4-knock-out mice Sec46Ala-Gpx4(+/+) knock-in animals are not viable but undergo intrauterine resorption between embryonic day 6 and 7 (E6-7). In contrast, heterozygous knock-in mice (Sec46Ala-Gpx4(-/+)) are viable, fertile and do not show major phenotypic alterations. Interestingly, homozygous Alox15 deficiency did not rescue the U46A-Gpx4(+/+) mice from embryonic lethality. In fact, when heterozygous U46A-Gpx4(-/+) mice were stepwise crossed into an Alox15-deficent background, no viable U46A-Gpx4(+/+)+Alox15(-/-) individuals were obtained. However, we were able to identify U46A-Gpx4(+/+)+Alox15(-/-) embryos in the state of resorption around E7. These data suggest that the lack of catalytic activity is the major reason for the embryonic lethality of Gpx4(-/-) mice and that systemic inactivation of the Alox15 gene does not rescue homozygous knock-in mice expressing catalytically silent Gpx4.

Does selenium supplementation affect thyroid function?

DEFF Research Database (Denmark)

Winther, Kristian Hillert; Bonnema, Steen Joop; Cold, Frederik

2015-01-01

OBJECTIVE: Selenium is present in the active site of proteins important for thyroid hormone synthesis and metabolism. The objective of this study is to investigate the effect of selenium supplementation in different doses on thyroid function, under conditions of suboptimal dietary selenium intake....... DESIGN: The Danish PREvention of Cancer by Intervention with SElenium pilot study (DK-PRECISE) is a randomized, double-blinded, placebo-controlled trial. A total of 491 males and females aged 60-74 years were randomized to 100 μg (n=124), 200 μg (n=122), or 300 μg (n=119) selenium-enriched yeast......=0.015), respectively, per 100 μg/day increase, with insignificant differences between 6 months and 5 years. No significant effects were found for FT3 and FT3:FT4 ratio. CONCLUSIONS: In euthyroid subjects, selenium supplementation minutely and dose-dependently affects thyroid function, when compared...

Acute selenium poisoning in lambs

Energy Technology Data Exchange (ETDEWEB)

Gabbedy, B J; Dickson, J

1969-10-01

An outbreak of sodium selenite poisoning is reported in which 180 of 190 six-weeks-old lambs died. The estimated dose rate of the selenium was 6.4 mg/kg body weight. Liver concentrations of selenium at the time of poisoning averaged 64 ppM and 15 days later liver and kidney concentrations of selenium averaged 26 ppM and 7.4 ppM respectively.

Total selenium and selenium species in irrigation drain inflows to the Salton Sea, California, April and July 2007

Science.gov (United States)

May, Thomas W.; Walther, Michael J.; Saiki, Michael K.; Brumbaugh, William G.

2007-01-01

This report presents the results for two sampling periods during a 4-year monitoring survey to provide a characterization of selenium concentrations in selected irrigation drains flowing into the Salton Sea, California. Total selenium, selenium species, and total suspended solids were determined in water samples, and total selenium was determined in sediment, detritus, and biota that included algae, plankton, midge larvae (family, Chironomidae), and two fish species-western mosquitofish (Gambusia affinis), and sailfin molly (Poecilia latipinna). In addition, sediments were analyzed for percent total organic carbon and particle size. Total selenium concentrations in water for both sampling periods ranged from 1.43 to 47.1 micrograms per liter, predominately as selenate, which is typical of waters leached out of selenium-contaminated marine shales under alkaline and oxidizing conditions. Total selenium concentrations ranged from 0.88 to 20.2 micrograms per gram in biota, and from 0.15 to 28.9 micrograms per gram in detritus and sediment.

Total selenium and selenium species in irrigation drain inflows to the Salton Sea, California, April and July 2008

Science.gov (United States)

May, Thomas W.; Walther, Michael J.; Saiki, Michael K.; Brumbaugh, William G.

2009-01-01

This report presents the results for two sampling periods (April 2008 and July 2008) during a 4-year monitoring program to characterize selenium concentrations in selected irrigation drains flowing into the Salton Sea, California. Total selenium, selenium species (dissolved selenite, selenate, organoselenium), and total suspended solids were determined in water samples and total selenium was determined in water column particulates and in sediment, detritus, and biota that included algae, plankton, midge larvae (family, Chironomidae), and two fish species - western mosquitofish (Gambusia affinis) and sailfin molly (Poecilia latipinna). In addition, sediments were analyzed for percent total organic carbon and particle size. Mean total selenium concentrations in water for both sampling periods ranged from 1.93 to 44.2 micrograms per liter, predominately as selenate, which is typical of waters where selenium is leached out of selenium-containing marine shales and associated soils under alkaline and oxidizing conditions. Total selenium concentrations (micrograms per gram dry weight) ranged as follows: algae, 0.75 to 3.39; plankton, 0.88 to 4.03; midges, 2.52 to 44.3; fish, 3.37 to 18.9; detritus, 1.11 to 13.6; sediment, 0.11 to 8.93.

Effects of Dietary Strawberry Supplementation on Antioxidant Biomarkers in Obese Adults with Above Optimal Serum Lipids

Directory of Open Access Journals (Sweden)

Arpita Basu

2016-01-01

Full Text Available Berries have shown several cardiovascular health benefits and have been associated with antioxidant functions in experimental models. Clinical studies are limited. We examined the antioxidant effects of freeze-dried strawberries (FDS in adults [n=60; age: 49±10 years; BMI: 36±5 kg/m2 (mean ± SD] with abdominal adiposity and elevated serum lipids. Participants were randomized to one of the following arms: low dose strawberry (25 g/day FDS, low dose control beverage (LD-C, high dose strawberry (50 g/d FDS, and high dose control beverage (HD-C for 12 weeks. Control beverages were matched for calories and total fiber. Plasma antioxidant capacity, trace elements (copper, iron, selenium, and zinc, whole blood glutathione (GSH, and enzyme activity (catalase, glutathione peroxidase, and glutathione reductase were examined at screening (0 week and after 12 weeks’ intervention. At 12 weeks, plasma antioxidant capacity and glutathione levels were higher in the strawberry versus control groups (low and high dose FDS: 45% and 42% for plasma antioxidant capacity and 28% and 36% for glutathione, resp.; glutathione was higher in the high versus low dose strawberry group (all p<0.05. Serum catalase activity was higher in the low dose strawberry (43% versus control group (p<0.01. No differences were noted in plasma trace elements and glutathione enzyme activity. Dietary strawberries may selectively increase plasma antioxidant biomarkers in obese adults with elevated lipids.

A comparison of the uptake of [75Se]Selenite [75Se] Selenomethionine and [35S]methionine by the tissues of ewes and lambs

International Nuclear Information System (INIS)

Fuss, C.N.; Godwin, K.O.

1975-01-01

The fate of selenium, given as Na 2 75 SeO 3 , or [ 75 Se] selenomethionine, and of [ 35 S]methionine administered intravenously to ewes and lambs, has been examined. The main intention was to follow the incorporation of selenium into protein in a number of tissues, including liver and kidney, and to measure the extent of that incorporation of selenoamino acid, particularly with respect to the administration of selenite. The ewes chosen were lactating ewes with lambs at foot, and the lambs were animals which had been weaned on to fodder low in selenium and were recovering from white muscle disease with selenium therapy. These two experimental situations were chosen as they offered conditions under which selenium incorporation might be considered to be maximal. Entry of isotope into milk was rapid and was greater when 75 Se was given as the selenoamino acid than as selenite. In both ewes and lambs greater amounts of activity, derived from selenite, were bound to plasma proteins than to the proteins of milk. This was particularly evident in samples taken some hours after administration. This ability of the plasma to bind selenium was demonstrated by alkaline dialysis. Small, though significant amounts of selenium, derived from Na 2 75 SeO 3 , were incorporated as selenoamino acids into the proteins of liver, kidney and pancreas, as well as into the proteins of milk and plasma. In ewes, both selenomethionine and selenocystine were identified chromatographically in enzyme digests of defatted liver and kidney. Some differences occurred in the distribution of labelled compounds in organs from lactating ewes and recovering lambs. The incorporation of selenium into protein is discussed briefly in relation to the recent findings of an association between selenium and the enzyme glutathione peroxidase. (author)

The Cultivation and SeleniumEnrichment of SeleniumEnriched Earthworm

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SUN Xiao-fei

2014-12-01

Full Text Available As a bio-carrier, Eisenia fetida was fed with cow dung that added with sodium selenite in order to transfer inorganic selenium(Se into organic selenium. Targeting on survival rate and selenium content, the effects of five Se concentrations(0, 20, 40, 60, 80, 100 mg·kg-1 and four cultivation periods(15, 30, 45, 60 don earthworm growth and Se contents were investigated. The cultivation method with high survival rate, high Se content of earthworm and short breeding time would be screened out. The experimental results showed that the earthworm survival rate decreased and the Se content in earthworm increased with the increase of Se application and the extension of breeding time. The most optimummethod was screened out when the Se concentration was 80 mg·kg-1 and the cultivation period was 45 days, Se content in earthworm was up to 33.25 mg·kg-1.

Trace Element Analysis of Selenium

International Nuclear Information System (INIS)

Soliman, M.S.A.

2010-01-01

The present thesis divided into four chapters as follows:Chapter (1):This chapter contains an introduction on different oxidation states of organic and inorganic species for selenium in environmental and biological samples, the process for separation of selenium from these samples and the importance of selenium as a component for these samples. Also gives notes about the techniques which are used in the elemental analysis for selenium species and the detection limits for selenium in these techniques, selenium species in human body and the importance of these species in protecting the body from the different types of cancer and the sources of selenium in environmental samples (soil and water) and distribution levels of selenium in these samples.Chapter (2):This chapter is divided into two parts :The first part deals with the sample collection process for environmental samples (underground water, soil) and the wet digestion ( microwave digestion ) process of soil samples. It also contains the theory of work of the closed microwave digestion system.The second part contains detailed information concerning the theoretical considerations of the used analytical techniques. These techniques include Hydride generation - Atomic Absorption Spectrometer (HG-AAS), Inductively Coupled Plasma Mass Spectrometer (ICP-MS) and Neutron Activation Analysis (NAA).Chapter (3): This chapter includes the methods of sampling, sample preparation, and sample digesition. The measures of quality assurance are disscused in this chapter. It describes in details the closed microwave digestion technique and the analytical methods used in this study which are present in Central Laboratory for Elemental and Isotopic Analysis (CLEIA) and the Egypt Second Research Reactor (ETRR-2). The described techniques are Atomic Absorption Spectrometer (AAS 6 vario, Analytical Jena GmbH, Germany), JMS-PLASMAX2 Mass Spectrometer (ICP-MS) and the Egypt Second Research Reactor (NAA).

Oxidative stress by Se-deficiency and dynamics of biotrace elements

International Nuclear Information System (INIS)

Sakuma, Yasunobu; Tsuyuki, Satoshi; Nagayama, Atsuko; Matsuoka, Keisuke; Honda, Chikako; Endo, Kazutoyo

2006-01-01

Metal ions such as Mn, Fe, Cu, Zn, Se are located at the center of the antioxidants in biological systems. Selenium (Se) is contained in GSH-Px (glutathione peroxidase), one of the antioxidants, and is related to various other metal ions to keep redox balance in organism. In the present study, Mn contents in cell fractions of liver homogenates of Se-deficient rat, and control (normal) rats were determined by means of INAA. The results showed that the Mn contents in microsomal fraction of male Se-deficient rats were greater than the control for male rats, and that the trend was different for female rats. The results were presented together with the results of SOD and TBARS. (author)

Acute selenium poisoning in cattle

Energy Technology Data Exchange (ETDEWEB)

Shortridge, E H; O' Hara, P J; Marshall, P M

1971-01-01

Three hundred and seventy-six (67%) of 557 calves of approximately 150-200 kg live-weight died following subcutaneous injection of a solution containing 100 mg selenium as sodium selenite. Eight per cent of the 254 heifer calves and 56% of the 303 steers died. The calves had endured the stress of being weaned twice and held in stockyards twice as well as encountering wet weather during the 4 days before receiving the selenium. The heifer calves were also vaccinated with Br. abortus strain 19 vaccine at the same time as receiving the selenium. The clinical signs and pathological findings of circulatory failure and myocardial damage were similar to those previously reported in acute selenium poisoning.

Peroxidase enzymes regulate collagen extracellular matrix biosynthesis.

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DeNichilo, Mark O; Panagopoulos, Vasilios; Rayner, Timothy E; Borowicz, Romana A; Greenwood, John E; Evdokiou, Andreas

2015-05-01

Myeloperoxidase and eosinophil peroxidase are heme-containing enzymes often physically associated with fibrotic tissue and cancer in various organs, without any direct involvement in promoting fibroblast recruitment and extracellular matrix (ECM) biosynthesis at these sites. We report herein novel findings that show peroxidase enzymes possess a well-conserved profibrogenic capacity to stimulate the migration of fibroblastic cells and promote their ability to secrete collagenous proteins to generate a functional ECM both in vitro and in vivo. Mechanistic studies conducted using cultured fibroblasts show that these cells are capable of rapidly binding and internalizing both myeloperoxidase and eosinophil peroxidase. Peroxidase enzymes stimulate collagen biosynthesis at a post-translational level in a prolyl 4-hydroxylase-dependent manner that does not require ascorbic acid. This response was blocked by the irreversible myeloperoxidase inhibitor 4-amino-benzoic acid hydrazide, indicating peroxidase catalytic activity is essential for collagen biosynthesis. These results suggest that peroxidase enzymes, such as myeloperoxidase and eosinophil peroxidase, may play a fundamental role in regulating the recruitment of fibroblast and the biosynthesis of collagen ECM at sites of normal tissue repair and fibrosis, with enormous implications for many disease states where infiltrating inflammatory cells deposit peroxidases. Copyright © 2015 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.

Peroxidase activity as a marker for estrogenicity

International Nuclear Information System (INIS)

Levy, J.; Liel, Y.; Glick, S.M.

1981-01-01

We examined the possibility that peroxidase activity might be a marker for estrogen activity in established estrogen-dependent tissues: dimethylbenz[a]anthracene (DMBA)-induced rat mammary tumours and human breast cancer. In DMBA-induced tumours undergoing regression after ovariectomy or tamoxifen treatment, tumour size decreased by 50%, estradiol receptors (ER) and progesterone receptors (PgR) decreased by 25 and 20%, respectively, but peroxidase activity paradoxically increased six- to sevenfold. In DMBA tumours stimulated by estradiol treatment or by the cessation of tamoxifen administration in intact rats, tumour size increased threefold. ER and PgR increased two- and threefold, respectively, while peroxidase activity decreased 50%. These data indicate an inverse relation between tumour growth, ER and PgR on the one hand, and peroxidase activity on the other. In the human breast cancers there was a singificant negative relation between the presence of ER and peroxidase activity. By using a calibrated Sephadex G-100 column it was shown that uterine peroxidase differs in molecular weight from the peroxidase of rat mammary tumours and that of human breast cancer. (author)

Selenium Utilization Strategy by Microalgae

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Hiroya Araie

2009-11-01

Full Text Available The diversity of selenoproteins raises the question of why so many life forms require selenium. Selenoproteins are found in bacteria, archaea, and many eukaryotes. In photosynthetic microorganisms, the essential requirement for selenium has been reported in 33 species belonging to six phyla, although its biochemical significance is still unclear. According to genome databases, 20 species are defined as selenoprotein-producing organisms, including five photosynthetic organisms. In a marine coccolithophorid, Emiliania huxleyi (Haptophyta, we recently found unique characteristics of selenium utilization and novel selenoproteins using 75Se-tracer experiments. In E. huxleyi, selenite, not selenate, is the main substrate used and its uptake is driven by an ATP-dependent highaffinity, active transport system. Selenite is immediately metabolized to low-molecular mass compounds and partly converted to at least six selenoproteins, named EhSEP1–6. The most (EhSEP2 and second-most abundant selenoproteins (EhSEP1 are disulfide isomerase (PDI homologous protein and thioredoxin reductase (TR 1, respectively. Involvement of selenium in PDI is unique in this organism, while TR1 is also found in other organisms. In this review, we summarize physiological, biochemical, and molecular aspects of selenium utilization by microalgae and discuss their strategy of selenium utilization.

Shikonin protects dopaminergic cell line PC12 against 6-hydroxydopamine-mediated neurotoxicity via both glutathione-dependent and independent pathways and by inhibiting apoptosis.

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Esmaeilzadeh, Emran; Gardaneh, Mossa; Gharib, Ehsan; Sabouni, Farzaneh

2013-08-01

We have investigated the mechanism of shikonin function on protection of dopaminergic neurons against 6-OHDA-induced neurotoxicity. Treatment of rat pheochromocytoma cell line PC12 by serial dilutions of shikonin determined 10 μM of the compound as its optimum concentration for protection saving nearly 70 % of the cells against toxicity. Reverse transcription-PCR analysis of shikonin-treated cells showed threefold increase in mRNA levels of glutathione peroxidase-1 (GPX-1) as a representative component of the intracellular anti-oxidant defense system. To elucidate shikonin-GPX1 relationships and maximize protection, we transduced PC12 cells using recombinant lentivirus vectors that harbored GPX-1 coding sequence. This change upregulated GPX-1 expression, increased peroxidase activity and made neuronal cells resistant to 6-OHDA-mediated toxicity. More importantly, addition of shikonin to GPX1-overexpressing PC12 cells augmented GPX-1 protein content by eightfold leading to fivefold increase of enzymatic activity, 91 % cell survival against neurotoxicity and concomitant increases in intracellular glutathione (GSH) levels. Depletion of intracellular GSH rendered all cell groups highly susceptible to toxicity; however, shikonin was capable of partially saving them. Subsequently, GSH-independent superoxide dismutase mRNA was found upregulated by shikonin. As signs of apoptosis inhibition, the compound upregulated Bcl-2, downregulated Bax, and prevented cell nuclei from undergoing morphological changes typical of apoptosis. Also, a co-staining method demonstrated GPX-1 overexpression significantly increases the percent of live cells that is maximized by shikonin treatment. Our data indicate that shikonin as an antioxidant compound protects dopaminergic neurons against 6-OHDA toxicity and enhances their survival via both glutathione-dependent and direct anti-apoptotic pathways.

Oxidation of NAD dimers by horseradish peroxidase.

OpenAIRE

Avigliano, L; Carelli, V; Casini, A; Finazzi-Agrò, A; Liberatore, F

1985-01-01

Horseradish peroxidase catalyses the oxidation of NAD dimers, (NAD)2, to NAD+ in accordance with a reaction that is pH-dependent and requires 1 mol of O2 per 2 mol of (NAD)2. Horseradish peroxidase also catalyses the peroxidation of (NAD)2 to NAD+. In contrast, bacterial NADH peroxidase does not catalyse the peroxidation or the oxidation of (NAD)2. A free-radical mechanism is proposed for both horseradish-peroxidase-catalysed oxidation and peroxidation of (NAD)2.

Comparison of blood serum selenium concentrations from elderly population living in Sao Paulo city and literature data

International Nuclear Information System (INIS)

Saiki, Mitiko; Alves, Edson R.; Vasconcellos, Marina B.A.; Sumita, Nairo M.; Jaluul, Omar; Jacob Filho, Wilson

2005-01-01

Selenium is an essential nutrient of fundamental importance to human biology. This element is a component of the enzyme glutathione peroxidase that avoids the formation of free radicals protecting the organism against the oxidative damage. The Se concentrations in serum vary from one part of the world to another and this fact has been satisfactorily explained as a consequence of different Se intakes of the population. The main objective of this paper was the determination of serum Se concentrations in healthy elderly population included in a program for 'Successful Ageing' of the Hospital das Clinicas, Sao Paulo University Medical School. The blood samples were collected after a 12 h fast from 32 subjects aged 60 to 87 years. The blood was centrifuged after completely clotted and 4.0 mL of serum were freeze.dried for Se determination using neutron activation analysis. The serum samples and Se standard were irradiated for 16 h under a thermal neutron flux of de 5 x 10 12 n cm - '2 s -1 at the IEA-R1 nuclear reactor. Se was determined by measuring the gamma activity of 75 Se using an HGe detector coupled to a gamma ray spectrometer. The mean value of (0.92±0.07) μmol L -1 was obtained for serum Se concentration. This value is within the data used as reference values in clinical laboratories and those published in literature. Results obtained for certified reference materials NIST 1566b Oyster Tissue and NIST 1577b Bovine Liver showed good precision and agreed with the certified values. The relative standard deviation of the results was lower than 4.8 % and relative error lower than 0.97 %. Detection limit value obtained for serum Se determination was 0.003 μmol L-1. (author)

Total selenium and selenium species in irrigation drain inflows to the Salton Sea, California, October 2008 and January 2009

Science.gov (United States)

May, Thomas W.; Walther, Michael J.; Saiki, Michael K.; Brumbaugh, William G.

2009-01-01

This report presents the results for two sampling periods (October 2008 and January 2009) during a 4-year monitoring program to characterize selenium concentrations in selected irrigation drains flowing into the Salton Sea, California. Total selenium, selenium species (dissolved selenite, selenate, organoselenium), and total suspended solids were determined in water samples. Total selenium also was determined in water column particulates and in sediment, detritus, and biota that included algae, plankton, midge larvae (family, Chironomidae), and two fish species (western mosquitofish, Gambusia affinis, and sailfin molly, Poecilia latipinna). In addition, sediments were analyzed for percent total organic carbon and particle size. Mean total selenium concentrations in water for both sampling periods ranged from 1.00 to 33.6 micrograms per liter, predominately as selenate, which is typical of waters where selenium is leached out of selenium-containing marine shales and associated soils under alkaline and oxidizing conditions. Total selenium concentrations (micrograms per gram dry weight) ranged as follows: algae, 1.52 to 8.26; plankton, 0.79 to 3.66; midges, 2.68 to 50.6; fish, 3.09 to 30.4; detritus, 1.78 to 58.0; and sediment, 0.42 to 10.0.

Total selenium and selenium species in irrigation drain inflows to the Salton Sea, California, October 2007 and January 2008

Science.gov (United States)

May, Thomas W.; Walther, Michael J.; Saiki, Michael K.; Brumbaugh, William G.

2008-01-01

This report presents the results for two sampling periods (October 2007 and January 2008) during a 4-year monitoring program to characterize selenium concentrations in selected irrigation drains flowing into the Salton Sea, California. Total selenium, selenium species (selenite, selenate, organoselenium), and total suspended solids were determined in water samples, and total selenium was determined in sediment, detritus, and biota that included algae, plankton, midge larvae (family, Chironomidae), and two fish species?western mosquitofish (Gambusia affinis) and sailfin molly (Poecilia latipinna). In addition, sediments were analyzed for percent total organic carbon and particle size. Mean total selenium concentrations in water for both sampling periods ranged from 0.97 to 64.5 micrograms per liter, predominately as selenate, which is typical of waters where selenium is leached out of selenium-containing marine shales and associated soils under alkaline and oxidizing conditions. Total selenium concentrations (micrograms per gram dry weight) ranged as follows: algae, 0.95 to 5.99; plankton, 0.15 to 19.3; midges, 1.39 to 15.4; fish, 3.71 to 25.1; detritus, 0.85 to 21.7; sediment, 0.32 to 7.28.

Low plasma selenium concentrations in critically ill children: the interaction effect between inflammation and selenium deficiency

Science.gov (United States)

2014-01-01

Introduction Low plasma selenium concentrations are frequent in critically ill patients. However, whether this is due to systemic inflammation, a deficient nutritional state or both is still not clear. We aimed to determine the factors associated with low plasma selenium in critically ill children while considering the inflammatory response and nutritional status. Method A prospective study was conducted in 173 children (median age 34 months) with systemic inflammatory response who had plasma selenium concentrations assessed 48 hours after admission and on the 5th day of ICU stay. The normal reference range was 0.58 μmol/L to 1.6 μmol/L. The outcome variable was ‘low plasma selenium’, which was defined as plasma selenium values below the distribution median during this period. The main explanatory variables were age, malnutrition, sepsis, C-reactive protein (CRP), and clinical severity scores. The data were analyzed using a Binomial Generalized Estimating Equations model, which includes the correlation between admission and 5th day responses. Results Malnutrition and CRP were associated with low plasma selenium. The interaction effect between these two variables was significant. When CRP values were less than or equal to 40 mg/L, malnutrition was associated with low plasma selenium levels (odds ratio (OR) = 3.25, 95% confidence interval (CI) 1.39 to 7.63, P = 0.007; OR = 2.98, 95% CI 1.26 to 7.06, P = 0.013; OR = 2.49, 95% CI 1.01 to 6.17, P = 0.049, for CRP = 10, 20 and 40 mg/L, respectively). This effect decreased as CRP concentrations increased and there was loose significance when CRP values were >40 mg/L. Similarly, the effect of CRP on low plasma selenium was significant for well-nourished patients (OR = 1.13; 95% CI 1.06 to 1.22, P selenium. This interaction should be considered when interpreting plasma concentrations as an index of selenium status in patients with systemic inflammation as well as in the decision

Joint refinery selenium treatability study

International Nuclear Information System (INIS)

Meyer, C.L.; Folwarkow, S.

1993-01-01

The San Francisco Regional Water Quality Control Board recently established mass limits on discharges of selenium to the San Francisco Bay from several petroleum refineries. The refineries had been working independently to develop control strategies, including both source control and treatment options, for removal of selenium from their discharges. By January 1992, over fifty different combinations of treatment technologies, wastewater streams, and pretreatment steps had been investigated to determine their effectiveness and feasibility as selenium removal processes. No treatment process studied could achieve the required mass limits without serious negative environmental consequences, such as generation of large amounts of hazardous sludge. To better facilitate the development of a feasible selenium treatment process, the six Bay Area refineries shared results of their studies and identified several technologies that, with further work, could be developed further. This additional work is currently being carried out as part of a joint selenium treatability study sponsored by the Western States Petroleum Association. A review of the previous source control and treatment studies, along with a description of the current treatability studies will be discussed

Selenium content of foods purchased or produced in Ohio.

Science.gov (United States)

Snook, J T; Kinsey, D; Palmquist, D L; DeLany, J P; Vivian, V M; Moxon, A L

1987-06-01

Approximately 450 samples of about 100 types of foods consumed by rural and urban Ohioans were analyzed for selenium. Meat, dairy products, eggs, and grain products produced in Ohio have considerably lower selenium content than corresponding products produced in high selenium areas, such as South Dakota. Retail Ohio foods with interregional distribution tended to be higher in selenium content than corresponding foods produced in Ohio. Best sources of selenium in Ohio foods commonly consumed were meat and pasta products. Poor sources of selenium were fruits, most vegetables, candies, sweeteners, and alcoholic and nonalcoholic beverages. Establishment of an accurate data base for selenium depends on knowledge of the interregional distribution of foods, the selenium content of foods at their production site, and the selenium content of foods with wide local distribution.

Recovery of stream communities from experimental selenium exposure

Energy Technology Data Exchange (ETDEWEB)

Swift, M.C.; Kuklinskal, B.; Ferkull, K. [Univ. of Minnesota, Monticello, MN (United States); Allen, K.N.; Hermanutz, R.O.; Roush, T.H.; Hedtke, S.F. [Environmental Protection Agency, Duluth, MN (United States). Environmental Research Lab.

1994-12-31

The effects of selenium on stream communities and their recovery from those effects were studied at MERS from 1987--1991. Selenium was dosed into two replicate streams each at concentrations of 30, 10, 2.5 and 0 (control) {mu}g L{sup {minus}1} for 18, 30, and 12 months, respectively. Recovery was monitored for three (30) or two (1 0, 2.5) years following cessation of selenium dosing. Selenium rapidly accumulated in the sediment, plants, macroinvertebrates and fish during dosing. Selenium concentrations in sediment, macroinvertebrates, and plants were as high as 2X--4X, 2X--4X, and 1X--1OX the dosed concentration in the 30, 10, and 2.5 treatments, respectively. Selenium decreased relatively rapidly following cessation of dosing. By two years after dosing ceased, selenium concentrations in plants and macroinvertebrates were little different from the controls; selenium in sediment from the 30 and 10 streams was still higher than in the control streams two years after dosing ceased. The macroinvertebrate community changed little during the dosing and recovery period. Commonly used indices of community structure showed no effect of selenium dosing. The isopod Asellus and oligochaetes in the family Tubificidae decreased rapidly following the onset of selenium dosing; their recovery following cessation of dosing was slow.

Determination of selenium via the fluorescence quenching effect of selenium on hemoglobin-catalyzed peroxidative reaction.

Science.gov (United States)

Chen, Ya-Hong; Zhang, Ya-Nan; Tian, Feng-Shou

2015-05-01

A new method for the determination of selenium based on its fluorescence quenching on the hemoglobin-catalyzed reaction of H2 O2 and l-tyrosine has been established. The effect of pH, foreign ions and the optimization of variables on the determination of selenium was examined. The calibration curve was found to be linear between the fluorescence quenching (F0 /F) and the concentration of selenium within the range of 0.16-4.00 µg/mL. The detection limit was 1.96 ng/mL and the relative standard deviation was 3.14%. This method can be used for the determination of selenium in Se-enriched garlic bulbs with satisfactory results. Copyright © 2014 John Wiley & Sons, Ltd.

Analysis of manganese superoxide dismutase (MnSOD: Ala-9Val and glutathione peroxidase (GSH-Px: Pro 197 Leu gene polymorphisms in mood disorders.

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Birgül Elbozan Cumurcu

2013-05-01

Full Text Available We investigated the etiopathogenetic role of manganese superoxide dismutase (MnSOD (Ala-9Val and glutathione peroxidase (GSH-Px (Pro 197 Leu gene polymorphisms in patients diagnosed with major depressive disorder (MDD and bipolar I disorder (BD. Eighty patients with MDD, 82 patients with BD (total 162 patients and 96 healthy controls were enrolled in this study and genotyped using a Real Time-Quantitative Polymer Chain Reaction (RT-qPCR-based method. The patients with BD and MDD and the controls had a similar distribution of the genotypes and alleles in the Ala-9Val MnSOD gene polymorphism. Comparison of the MDD group and control group regarding the Pro197 Leu GSH-Px gene polymorphism revealed similar genotype distribution but different allele distribution. The BD group and control group were similar both for genotypes and for alleles when compared regarding the Pro 197 Leu GSH-Px gene polymorphism. The combined analysis (MDD plus BD also failed to find any association between the Ala-9Val MnSOD and Pro 197 Leu GSH-Px gene polymorphism. Although small statistical power of the current study the significant difference between patients with depression and the control group for the Pro 197 Leu GSH-Px polymorphism indicates that the distribution of these alleles may have a contribution in the physiopathogenesis of depression. One of the limitation of the current study is that the sample size is too small. Understanding of the exact role of Pro 197 LeuGSH-Px polymorphism in the development of depression needs to further studies with more sample size and high statistical power.

Glutathione system in Wolfram syndrome 1‑deficient mice.

Science.gov (United States)

Porosk, Rando; Kilk, Kalle; Mahlapuu, Riina; Terasmaa, Anton; Soomets, Ursel

2017-11-01

Wolfram syndrome 1 (WS) is a rare neurodegenerative disease that is caused by mutations in the Wolfram syndrome 1 (WFS1) gene, which encodes the endoplasmic reticulum (ER) glycoprotein wolframin. The pathophysiology of WS is ER stress, which is generally considered to induce oxidative stress. As WS has a well‑defined monogenetic origin and a model for chronic ER stress, the present study aimed to characterize how glutathione (GSH), a major intracellular antioxidant, was related to the disease and its progression. The concentration of GSH and the activities of reduction/oxidation system enzymes GSH peroxidase and GSH reductase were measured in Wfs1‑deficient mice. The GSH content was lower in most of the studied tissues, and the activities of antioxidative enzymes varied between the heart, kidneys and liver tissues. The results indicated that GSH may be needed for ER stress control; however, chronic ER stress from the genetic syndrome eventually depletes the cellular GSH pool and leads to increased oxidative stress.

"Chitin-specific" peroxidases in plants.

Science.gov (United States)

Maksimov, I V; Cherepanova, E A; Khairullin, R M

2003-01-01

The activity of various plant peroxidases and the ability of their individual isoforms to bind chitin was studied. Some increase in peroxidase activity was observed in crude extracts in the presence of chitin. Activated peroxidases of some species fell in the fraction not sorbed on chitin and those of other species can bind chitin. Only anionic isoperoxidases from oat (Avena sativa), rice (Oryza sativa), horseradish (Armoracia rusticana), garden radish (Raphanus sativus var. radicula), peanut (Arachis hypogaea), and tobacco (Nicotiana tabacum Link et Otto) were sorbed on chitin. Both anionic and cationic isoforms from pea (Pisum sativum), galega(Galega orientalis), cucumber (Cucumis sativus), and zucchini (Cucurbita pepo L.) were sorbed on chitin. Peroxidase activation under the influence of chitin was correlated to the processes that occur during hypersensitive reaction and lignification of sites, in which pathogenic fungus penetrates into a plant. The role of chitin-specific isoperoxidases in inhibition of fungal growth and connection of this phenomenon with structural characteristics of isoperoxidases are also discussed.

Distribution and mode of occurrence of selenium in US coals

Science.gov (United States)

Coleman, L.; Bragg, L.J.; Finkelman, R.B.

1993-01-01

Selenium excess and deficiency have been established as the cause of various health problems in man and animals. Combustion of fossil fuels, especially coal, may be a major source of the anthropogenic introduction of selenium in the environment. Coal is enriched in selenium relative to selenium's concentration in most other rocks and relative to selenium in the Earth's crust. Data from almost 9,000 coal samples have been used to determine the concentration and distribution of selenium in US coals. The geometric mean concentration of selenium in US coal is 1.7 ppm. The highest mean selenium value (geometric mean 4.7 ppm) is in the Texas Region. Atlantic Coast (Virginia and North Carolina) and Alaska coals have the lowest geometric means (0.2 and 0.42 ppm, respectively). All western coal regions have mean selenium concentrations of less than 2.0 ppm. In contrast, all coal basins east of the Rocky Mountains (except for several small basins in Rhode Island, Virginia, and North Carolina) have mean selenium values of 1.9 or greater. Generally, variations in selenium concentration do not correlate with variations in ash yield, pyritic sulphur, or organic sulphur concentrations. This may be the result of multiple sources of selenium; however, in some non-marine basins with restricted sources of selenium, selenium has positive correlations with other coal quality parameters. Selenium occurs in several forms in coal but appears to be chiefly associated with the organic fraction, probably substituting for organic sulphur. Other important forms of selenium in coal are selenium-bearing pyrite, selenium-bearing galena, and lead selenide (clausthalite). Water-soluble and ion-exchangeable selenium also have been reported. ?? 1993 Copyright Science and Technology Letters.

The relationship between selenium and gastric cancer

International Nuclear Information System (INIS)

Shi Kuixiong; Ma Guansheng; Zhang Tingyu; Cheng Wufeng; Mao Dajuan; Pan Bixia; Xu Xiuxian

1993-01-01

Both sodium selenite and selenium yeast were chosen to block the MNNG mutagenesis. The inhibition rates were 66.5% and 37.9% respectively. The selenium levels in hair, serum and gastric juice, and the contents of nitrosamine in gastric juice were also determined. The results showed that the selenium levels were SG > CAG and Dys > GC (p CAG, Dyas and GC (p < 0.05). 19 cases of CAG patients treated with selenium yeast and 16 cases of the control were observed. After 10 weeks, the selenium levels in serum for the treated group were significantly increased. The symptoms of CAG patients seemed to be alleviated

Loss of selenium-binding protein 1 decreases sensitivity to clastogens and intracellular selenium content in HeLa cells

Science.gov (United States)

Selenium-binding protein 1 (SBP1) is not a selenoprotein but structurally binds selenium. Loss of SBP1 during carcinogenesis usually predicts poor prognosis. Because genome instability is a hallmark of cancer, we hypothesized that loss of SBP1 modulates cellular selenium content and the response of ...

Selenium plating of aluminium and nickel surfaces

International Nuclear Information System (INIS)

Qureshi, N.; Shams, N.; Kamal, A.; Ashraf, A.

1993-01-01

Selenium exhibits photovoltaic and photoconductive properties. This makes selenium useful in the production of photocells, exposure meters for photographic use, in solar cells, etc. In commerce, selenium coated surfaces are extensively used as photo receptive drums in the xerography machines for reproducing documents. Laboratory experiments were designed to obtain selenium plating on different materials. Of the various electrodes tested for cathodic deposition, anodized aluminum and nickel plated copper were found to give good results. (author)

Is selenium supplementation in autoimmune thyroid diseases justified?

Science.gov (United States)

Winther, Kristian H; Bonnema, Steen J; Hegedüs, Laszlo

2017-10-01

This review provides an appraisal of recent evidence for or against selenium supplementation in patients with autoimmune thyroid diseases, and discusses possible effect mechanisms. Epidemiological data suggest an increased prevalence of autoimmune thyroid diseases under conditions of low dietary selenium intake. Two systematic reviews have evaluated controlled trials among patients with autoimmune thyroiditis and report that selenium supplementation decreases circulating thyroid autoantibodies. The immunomodulatory effects of selenium might involve reducing proinflammatory cytokine release. However, clinically relevant effects of selenium supplementation, including improvement in quality of life, are more elusive. In Graves' disease, some, but not all, trials indicate that adjuvant selenium supplementation enhances the restoration of biochemical euthyroidism, and might benefit patients with mild Graves' orbitopathy. The use of selenium supplementation as adjuvant therapy to standard thyroid medication may be widespread, but a growing body of evidence yields equivocal results. The available evidence from trials does not support routine selenium supplementation in the standard treatment of patients with autoimmune thyroiditis or Graves' disease. However, correction of moderate to severe selenium deficiency may offer benefits in preventing, as well as treating, these disorders. Molecular mechanisms have been proposed, but further studies are needed.

Direct Electrochemistry of Horseradish Peroxidase-Gold Nanoparticles Conjugate

Directory of Open Access Journals (Sweden)

Chanchal K. Mitra

2009-02-01

Full Text Available We have studied the direct electrochemistry of horseradish peroxidase (HRP coupled to gold nanoparticles (AuNP using electrochemical techniques, which provide some insight in the application of biosensors as tools for diagnostics because HRP is widely used in clinical diagnostics kits. AuNP capped with (i glutathione and (ii lipoic acid was covalently linked to HRP. The immobilized HRP/AuNP conjugate showed characteristic redox peaks at a gold electrode. It displayed good electrocatalytic response to the reduction of H2O2, with good sensitivity and without any electron mediator. The covalent linking of HRP and AuNP did not affect the activity of the enzyme significantly. The response of the electrode towards the different concentrations of H2O2 showed the characteristics of Michaelis Menten enzyme kinetics with an optimum pH between 7.0 to 8.0. The preparation of the sensor involves single layer of enzyme, which can be carried out efficiently and is also highly reproducible when compared to other systems involving the layer-by-layer assembly, adsorption or encapsulation of the enzyme. The immobilized AuNP-HRP can be used for immunosensor applications

Effect of an aqueous extract of Cucurbita ficifolia Bouché on the glutathione redox cycle in mice with STZ-induced diabetes.

Science.gov (United States)

Díaz-Flores, M; Angeles-Mejia, S; Baiza-Gutman, L A; Medina-Navarro, R; Hernández-Saavedra, D; Ortega-Camarillo, C; Roman-Ramos, R; Cruz, M; Alarcon-Aguilar, F J

2012-10-31

Cucurbita ficifolia is used in Mexican traditional medicine as an anti-diabetic and anti-inflammatory agent and its actions can be mediated by antioxidant mechanisms. Disturbance in the homeostasis of glutathione has been implicated in the etiology and progression of diabetes mellitus and its complications. It was evaluated, the effect of an aqueous extract of Cucurbita ficifolia on glycemia, plasma lipid peroxidation; as well as levels of reduced (GSH) and oxidized (GSSG) glutathione and activities of enzymes involved in glutathione redox cycle: glutathione peroxidase (GPx) and glutathione reductase (GR) in liver, pancreas, kidney and heart homogenates of streptozotocin-induced diabetic mice. Increased blood glucose and lipid peroxidation, together with decreased of GSH concentration, GSH/GSSG ratio and its redox potential (E(h)), and enhanced activity of GPx and GR in liver, pancreas and kidney were the salient features observed in diabetic mice. Administration of the aqueous extract of Cucurbita ficifolia to diabetic mice for 30 days, used at a dose of 200 mg/kg, resulted in a significant reduction in glycemia, polydipsia, hyperphagia and plasma lipid peroxidation. Moreover, GSH was increased in liver, pancreas and kidney, and GSSG was reduced in liver, pancreas and heart, therefore GSH/GSSG ratio and its E(h) were restored. Also, the activities involved in the glutathione cycle were decreased, reaching similar values to controls. An aqueous extract of Cucurbita ficifolia with hypoglycemic action, improve GSH redox state, increasing glutathione pool, GSH, GSH/GSSG ratio and its E(h), mechanism that can explain, at least in part, its antioxidant properties, supporting its use as an alternative treatment for the control of diabetes mellitus, and prevent the induction of complications by oxidative stress. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Impact of Selenium Supplementation on Growth and Selenium Accumulation on Spinach (Spinacia oleracea L.) Plants

OpenAIRE

Azadeh SAFFARYAZDI; Mehrdad LAHOUTI; Ali GANJEALI; Hassan BAYAT

2012-01-01

Selenium (Se) has been proved to be an essential element for humans and animals. However, less is known about its effects on plants. A hydroponic experiment was carried out to investigate the effects of selenium on growth, selenium accumulation and some physiological characteristics of spinach (Spinacia oleracea L. cv. �Missouri�) plants. Plants were grown in Hoagland nutrient solution amended with sodium selenite at 0 (control), 1, 2, 4, 6 and 10 mg.L-1 for 28 days. Growth parameters like sh...

Glutathione-mediated detoxification of halobenzoquinone drinking water disinfection byproducts in T24 cells.

Science.gov (United States)

Li, Jinhua; Wang, Wei; Zhang, Hongquan; Le, X Chris; Li, Xing-Fang

2014-10-01

Halobenzoquinones (HBQs) are a new class of drinking water disinfection byproducts (DBPs) and are capable of producing reactive oxygen species and causing oxidative damage to proteins and DNA in T24 human bladder carcinoma cells. However, the exact mechanism of the cytotoxicity of HBQs is unknown. Here, we investigated the role of glutathione (GSH) and GSH-related enzymes including glutathione S-transferase (GST) and glutathione peroxidase (GPx) in defense against HBQ-induced cytotoxicity in T24 cells. The HBQs are 2,6-dichloro-1,4-benzoquinone (DCBQ), 2,6-dichloro-3-methyl-1,4-benzoquinone (DCMBQ), 2,3,6-trichloro-1,4-benzoquinone (TriCBQ), and 2,6-dibromobenzoquinone (DBBQ). We found that depletion of cellular GSH could sensitize cells to HBQs and extracellular GSH supplementation could attenuate HBQ-induced cytotoxicity. HBQs caused significant cellular GSH depletion and increased cellular GST activities in a concentration-dependent manner. Our mass spectrometry study confirms that HBQs can conjugate with GSH, explaining in part the mechanism of GSH depletion by HBQs. The effects of HBQs on GPx activity are compound dependent; DCMBQ and DBBQ decrease cellular GPx activities, whereas DCBQ and TriCBQ have no significant effects. Pearson correlation analysis shows that the cellular GSH level is inversely correlated with ROS production and cellular GST activity in HBQ-treated cells. These results support a GSH and GSH-related enzyme-mediated detoxification mechanism of HBQs in T24 cells. © The Author 2014. Published by Oxford University Press on behalf of the Society of Toxicology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Colorimetric Glucose Assay Based on Magnetic Particles Having Pseudo-peroxidase Activity and Immobilized Glucose Oxidase.

Science.gov (United States)

Martinkova, Pavla; Opatrilova, Radka; Kruzliak, Peter; Styriak, Igor; Pohanka, Miroslav

2016-05-01

Magnetic particles (MPs) are currently used as a suitable alternative for peroxidase in the construction of novel biosensors, analytic and diagnostic methods. Their better chemical and thermal stabilities predestine them as appropriate pseudo-enzymatic catalysts. In this point of view, our research was focused on preparation of simply and fast method for immobilization of glucose oxidase onto surface of MPs with peroxidase-like activity. Spectrophotometric method (wavelength 450 nm) optimized for glucose determination using modified MPs has been successfully developed. Concentration curve for optimization of method was assayed, and Michaelis-Menten constant (K m) calculated, maximum reaction rate (V max), limit of detection, and correlation coefficient were determined to be 0.13 mmol/l (2.34 mg/dl), 1.79 pkat, 3.74 µmol/l (0.067 mg/dl), and 0.996, respectively. Interferences of other sugars such as sucrose, sorbitol, deoxyribose, maltose, and fructose were determined as well as effect of substances presenting in plasma (ascorbic acid, reduced glutathione, trolox, and urea). Results in comparison with positive and negative controls showed no interferences of the other sugars and no influence of plasma substances to measuring of glucose. The constructed method showed corresponding results with linear dependence and a correlation coefficient of 0.997. Possibility of repeated use of modified MPs was successfully proved.

Structure of soybean seed coat peroxidase: a plant peroxidase with unusual stability and haem-apoprotein interactions

DEFF Research Database (Denmark)

Henriksen, A; Mirza, O; Indiani, C

2001-01-01

Soybean seed coat peroxidase (SBP) is a peroxidase with extraordinary stability and catalytic properties. It belongs to the family of class III plant peroxidases that can oxidize a wide variety of organic and inorganic substrates using hydrogen peroxide. Because the plant enzyme is a heterogeneous...... glycoprotein, SBP was produced recombinant in Escherichia coli for the present crystallographic study. The three-dimensional structure of SBP shows a bound tris(hydroxymethyl)aminomethane molecule (TRIS). This TRIS molecule has hydrogen bonds to active site residues corresponding to the residues that interact...... with the small phenolic substrate ferulic acid in the horseradish peroxidase C (HRPC):ferulic acid complex. TRIS is positioned in what has been described as a secondary substrate-binding site in HRPC, and the structure of the SBP:TRIS complex indicates that this secondary substrate-binding site could...

Arsenic and selenium in microbial metabolism

Science.gov (United States)

Stolz, John F.; Basu, Partha; Santini, Joanne M.; Oremland, Ronald S.

2006-01-01

Arsenic and selenium are readily metabolized by prokaryotes, participating in a full range of metabolic functions including assimilation, methylation, detoxification, and anaerobic respiration. Arsenic speciation and mobility is affected by microbes through oxidation/reduction reactions as part of resistance and respiratory processes. A robust arsenic cycle has been demonstrated in diverse environments. Respiratory arsenate reductases, arsenic methyltransferases, and new components in arsenic resistance have been recently described. The requirement for selenium stems primarily from its incorporation into selenocysteine and its function in selenoenzymes. Selenium oxyanions can serve as an electron acceptor in anaerobic respiration, forming distinct nanoparticles of elemental selenium that may be enriched in (76)Se. The biogenesis of selenoproteins has been elucidated, and selenium methyltransferases and a respiratory selenate reductase have also been described. This review highlights recent advances in ecology, biochemistry, and molecular biology and provides a prelude to the impact of genomics studies.

Selenium Level and Dyslipidemia in Rural Elderly Chinese

Science.gov (United States)

Su, Liqin; Gao, Sujuan; Unverzagt, Frederick W.; Cheng, Yibin; Hake, Ann M.; Xin, Pengju; Chen, Chen; Liu, Jingyi; Ma, Feng; Bian, Jianchao; Li, Ping; Jin, Yinlong

2015-01-01

Objective Higher selenium level has been hypothesized to have the potential to reduce the risk of cardiovascular diseases including dyslipidemia. However, results from previous studies are inconsistent. This study aims to determine the association between selenium level and dyslipidemia in elderly Chinese with relatively low selenium status. Methods A cross-sectional study of 1859 participants aged 65 or older from four rural counties in China was conducted. Serum total cholesterol (TC), triglycerides (TG), high density lipoprotein-cholesterol (HDLC) and low-density lipoprotein-cholesterol (LDLC), nail selenium concentration and APOE genotype were measured in all subjects. The four types of dyslipidemia were defined as >5.17mmol/L for High-TC, >1.69 mmol/L for High-TG, >3.36 mmol/L for High-LDLC, and selenium levels and the risk of dyslipidemia. Results Mean nail selenium concentration was 0.465μg/gin this sample. Rates for High-TC, High-LDLC, High-TG, Low-HDLC were 18.13%, 13.23%, 12.21% and 32.76% respectively. Results from logistic models indicated that higher selenium levels were significantly associated with higher risk of High-TC, High-LDLC and lower risk of Low-HDLC adjusting for covariates (p selenium quartile group, participants in selenium quartile groups 2, 3 and 4 had significantly higher rates of High-TC, High-LDLC, High-TG, and lower rate of Low-HDLC adjusting for covariates. No significant association was observed between selenium level and the risk of High-TG. APOEε4 carriers had higher rates of High-TC and High-LDLC. There was no interaction between selenium level and APOE with the rates of dyslipidemia. Conclusions Our results suggest long-term selenium exposure level may be associated with the risk of dyslipidemia in elderly population. Future studies are needed to examine the underlying mechanism of the association. PMID:26380972

Selenium in human milk: An Australian study

International Nuclear Information System (INIS)

Cumming, F.J.; Fardy, J.J.; Woodward, D.R.

1991-01-01

The aims of this Australian study were to determine (total) selenium concentration in breast milk and in maternal blood, and to assess the relationship between the two. The authors also aimed to assess the infants' selenium intake. Twenty lactating women from Brisbane (Queensland) participated in the study, at 6-12 weeks post-partum. Small samples (approximately 10 ml) of breast-milk were manually expressed at the beginning and end of a mid-morning feed, from the first breast offered at that feed. Venous blood samples (10 ml) were also collected from the mothers. Milk and blood samples were analyzed by neutron activation analysis. Babies' milk intake over a 24-hour period was estimated using a modified test-weighing technique. Infant selenium intakes were calculated directly for each infant, using his/her mother's milk selenium level and his/her own 24-hour breast milk intake. The mean selenium concentration in maternal blood was 101 (±SD 19) ng/g and in maternal serum 81 (±15) ng/g. Breast milk selenium concentrations (11.9 ± 3.5 ng/g) were fairly low by international standards. There was no correlation between selenium concentrations in milk and blood (or serum). The infants' 24-hour breast-milk intakes were 856 ± 172 g, and their selenium intakes were 10.7 ± 4.1 μg per day

Is selenium supplementation in autoimmune thyroid diseases justified?

DEFF Research Database (Denmark)

Winther, Kristian H.; Bonnema, Steen; Hegedüs, Laszlo

2017-01-01

PURPOSE OF REVIEW: This review provides an appraisal of recent evidence for or against selenium supplementation in patients with autoimmune thyroid diseases, and discusses possible effect mechanisms. RECENT FINDINGS: Epidemiological data suggest an increased prevalence of autoimmune thyroid...... diseases under conditions of low dietary selenium intake. Two systematic reviews have evaluated controlled trials among patients with autoimmune thyroiditis and report that selenium supplementation decreases circulating thyroid autoantibodies. The immunomodulatory effects of selenium might involve reducing...... proinflammatory cytokine release. However, clinically relevant effects of selenium supplementation, including improvement in quality of life, are more elusive. In Graves’ disease, some, but not all, trials indicate that adjuvant selenium supplementation enhances the restoration of biochemical euthyroidism...

Nanotoxicity of pure silica mediated through oxidant generation rather than glutathione depletion in human lung epithelial cells.

Science.gov (United States)

Akhtar, Mohd Javed; Ahamed, Maqusood; Kumar, Sudhir; Siddiqui, Huma; Patil, Govil; Ashquin, Mohd; Ahmad, Iqbal

2010-10-09

Though, oxidative stress has been implicated in silica nanoparticles induced toxicity both in vitro and in vivo, but no similarities exist regarding dose-response relationship. This discrepancy may, partly, be due to associated impurities of trace metals that may present in varying amounts. Here, cytotoxicity and oxidative stress parameters of two sizes (10 nm and 80 nm) of pure silica nanoparticles was determined in human lung epithelial cells (A549 cells). Both sizes of silica nanoparticles induced dose-dependent cytotoxicity as measured by MTT [3-(4,5-dimethyl thiazol-2-yl)-2,5-diphenyl tetrazolium bromide] and lactate dehydrogenase (LDH) assays. Silica nanoparticles were also found to induce oxidative stress in dose-dependent manner indicated by induction of reactive oxygen species (ROS) generation, and membrane lipid peroxidation (LPO). However, both sizes of silica nanoparticles had little effect on intracellular glutathione (GSH) level and the activities of glutathione metabolizing enzymes; glutathione reductase (GR) and glutathione peroxidase (GPx). Buthionine-[S,R]-sulfoximine (BSO) plus silica nanoparticles did not result in significant GSH depletion than that caused by BSO alone nor N-acetyl cysteine (NAC) afforded significant protection from ROS and LPO induced by silica nanoparticles. The rather unaltered level of GSH is also supported by finding no appreciable alteration in the level of GR and GPx. Our data suggest that the silica nanoparticles exert toxicity in A549 cells through the oxidant generation (ROS and LPO) rather than the depletion of GSH. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

Determination of total selenium and selenium distribution in the milk phases in commercial cow's milk by HG-AAS

Energy Technology Data Exchange (ETDEWEB)

Muniz-Naveiro, Oscar; Dominguez-Gonzalez, Raquel; Bermejo-Barrera, Adela; Bermejo-Barrera, Pilar [University of Santiago de Compostela, Department of Analytical Chemistry, Nutrition and Bromatology, Santiago de Compostela (Spain); Cocho, Jose A. [University Clinical Hospital, Laboratory of Metabolic and Nutritional Disorders, Santiago de Compostela (Spain); Fraga, Jose M. [University Clinical Hospital, Department of Pediatrics, Santiago de Compostela (Spain)

2005-03-01

A procedure has been developed for determining the selenium in cow's milk using hydride generation-atomic absorption spectrometry (HG-AAS) following microwave-assisted acid digestion. The selenium distributions in milk whey, fat and micellar casein phases were studied after separating the different phases by ultracentrifugation and determining the selenium in all of them. The detection limits obtained by HG-AAS for the whole milk, milk whey and micellar casein were 0.074, 0.065 and 0.075 {mu}g l{sup -1}, respectively. The accuracy for the whole milk was checked by using a Certified Reference Material CRM 8435 whole milk powder from NIST, and the analytical recoveries for the milk whey and casein micelles were 100.9 and 96.9%, respectively. A mass balance study of the determination of selenium in the different milk phases was carried out, obtaining values of 95.5-100.8%. The total content of selenium was determined in 37 milk samples from 15 different manufacturers, 19 whole milk samples and 18 skimmed milk samples. The selenium levels found were within the 8.5-21 {mu}g l{sup -1} range. The selenium distributions in the different milk phases were studied in 14 whole milk samples, and the highest selenium levels were found in milk whey (47.2-73.6%), while the lowest level was found for the fat phase (4.8-16.2%). A strong correlation was found between the selenium levels in whole milk and the selenium levels in the milk components. (orig.)

Tetra(p-tolyl)borate-functionalized solvent polymeric membrane: a facile and sensitive sensing platform for peroxidase and peroxidase mimetics.

Science.gov (United States)

Wang, Xuewei; Qin, Wei

2013-07-22

The determination of peroxidase activities is the basis for enzyme-labeled bioaffinity assays, peroxidase-mimicking DNAzymes- and nanoparticles-based assays, and characterization of the catalytic functions of peroxidase mimetics. Here, a facile, sensitive, and cost-effective solvent polymeric membrane-based peroxidase detection platform is described that utilizes reaction intermediates with different pKa values from those of substrates and final products. Several key but long-debated intermediates in the peroxidative oxidation of o-phenylenediamine (o-PD) have been identified and their charge states have been estimated. By using a solvent polymeric membrane functionalized by an appropriate substituted tetraphenylborate as a receptor, those cationic intermediates could be transferred into the membrane from the aqueous phase to induce a large cationic potential response. Thus, the potentiometric indication of the o-PD oxidation catalyzed by peroxidase or its mimetics can be fulfilled. Horseradish peroxidase has been detected with a detection limit at least two orders of magnitude lower than those obtained by spectrophotometric techniques and traditional membrane-based methods. As an example of peroxidase mimetics, G-quadruplex DNAzymes were probed by the intermediate-sensitive membrane and a label-free thrombin detection protocol was developed based on the catalytic activity of the thrombin-binding G-quadruplex aptamer. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

InterProScan Result: FS819198 [KAIKOcDNA[Archive

Lifescience Database Archive (English)

Full Text Available 000889 Glutathione peroxidase Molecular Function: glutathione peroxidase activity (GO:0004602)|Biological Pr...ocess: response to oxidative stress (GO:0006979)|Biological Process: oxidation reduction (GO:0055114) ...

Determinants of selenium in the toenail biomonitor

International Nuclear Information System (INIS)

Morris, J.S.; Spate, V.L.; Ngwenyama, R.A.

2006-01-01

The evaluation of human nails as a measure of selenium intake and to assess selenium status in critical tissues is now being used routinely to investigate hypotheses relating selenium status to chronic disease, especially cancer. In this study we report on our observations of the major determinants of toenail selenium concentrations. Toenail specimens (3575) were, under a protocol we provided, self-collected by adult females (1940, 54.3%) and males (1635, 45.7%) living in 111 of Missouri's 114 counties. The health-conscious participants ranged in age from 18 to 94 years with means of 53.7±14.1 and 56.4±14.2 years for females and males, respectively. Selenium supplement use was over represented, 39.1% and 42.7%, and smoking was under represented, 7.5% and 7.8%, for females and males, respectively. The major determinants of toenail selenium concentration were supplement use, sex and cigarette smoking. We found no overall correlations with age, body mass index or diet selection. (author)

Characterization of glutathione transferases involved in the pathogenicity of Alternaria brassicicola.

Science.gov (United States)

Calmes, Benoit; Morel-Rouhier, Mélanie; Bataillé-Simoneau, Nelly; Gelhaye, Eric; Guillemette, Thomas; Simoneau, Philippe

2015-06-18

Glutathione transferases (GSTs) represent an extended family of multifunctional proteins involved in detoxification processes and tolerance to oxidative stress. We thus anticipated that some GSTs could play an essential role in the protection of fungal necrotrophs against plant-derived toxic metabolites and reactive oxygen species that accumulate at the host-pathogen interface during infection. Mining the genome of the necrotrophic Brassica pathogen Alternaria brassicicola for glutathione transferase revealed 23 sequences, 17 of which could be clustered into the main classes previously defined for fungal GSTs and six were 'orphans'. Five isothiocyanate-inducible GSTs from five different classes were more thoroughly investigated. Analysis of their catalytic properties revealed that two GSTs, belonging to the GSTFuA and GTT1 classes, exhibited GSH transferase activity with isothiocyanates (ITC) and peroxidase activity with cumene hydroperoxide, respectively. Mutant deficient for these two GSTs were however neither more susceptible to ITC nor less aggressive than the wild-type parental strain. By contrast mutants deficient for two other GSTs, belonging to the Ure2pB and GSTO classes, were distinguished by their hyper-susceptibility to ITC and low aggressiveness against Brassica oleracea. In particular AbGSTO1 could participate in cell tolerance to ITC due to its glutathione-dependent thioltransferase activity. The fifth ITC-inducible GST belonged to the MAPEG class and although it was not possible to produce the soluble active form of this protein in a bacterial expression system, the corresponding deficient mutant failed to develop normal symptoms on host plant tissues. Among the five ITC-inducible GSTs analyzed in this study, three were found essential for full aggressiveness of A. brassicicola on host plant. This, to our knowledge is the first evidence that GSTs might be essential virulence factors for fungal necrotrophs.

Selenium balance in the adult cat in relation to intake of dietary sodium selenite and organically bound selenium

NARCIS (Netherlands)

Todd, S.E.; Thomas, D.G.; Hendriks, W.H.

2012-01-01

The response of cats to dietary sodium selenite (Na2SeO3) and organically bound selenium was studied in two separate studies with four cats per treatment and three levels of selenium supplementation (targets 1.0, 1.5 and 2.0 µg/g DM) for each Se source. Whole blood and plasma selenium concentrations

Optimization of selenizing conditions for Seleno-Lentinan and its characteristics.

Science.gov (United States)

Ren, Guangming; Li, Koukou; Hu, Yang; Yu, Min; Qu, Juanjuan; Xu, Xiuhong

2015-11-01

Lentinan was successfully modified with nitric acid-sodium selenite method based on L9(3(4)) orthogonal experiments. The optimum selenizing conditions were obtained according to selenium conversion rate as follows: Lentinan of 1.0g, pH of 4.5, temperature of 70°C and sodium selenite of 1.50g. The antioxidant activity assays in vitro (DPPH, reducing power, superoxide radicals and hydroxyl radicals) proved that Lentinan had stronger antioxidant activity after selenizing. The elevations of serum alanine aminotransferase and aspartate aminotransferase, as well as the abnormal hepatic architecture, verified that oral administration of Seleno-Lentinan (SL2-1) markedly alleviated oxidative damage in the liver of mice induced by D-gal. In addition, SL2-1 significantly increased total antioxidant capacity, activities and protein expressions of catalase and glutathione peroxidase and lowered malondialdehyde levels in serum and liver. Fourier transform infrared spectroscopy analysis indicated that selenium of SL2-1 was mostly existed as the formations of OSeO, SeO and SeOC. Scanning electron microscope coupled with energy dispersive X-ray spectroscopy analysis revealed that the surface structure and elemental components of Lentinan significantly changed after selenizing. The results are instructive for the development of organic selenium-supplement resource. Copyright © 2015 Elsevier B.V. All rights reserved.

GPX4 and GPX7 Over-Expression in Human Hepatocellular Carcinoma Tissues

Science.gov (United States)

Guerriero, E.; Capone, F.; Accardo, M.; Sorice, A.; Costantini, M.; Colonna, G.; Castello, G.

2015-01-01

Hepatocellular carcinoma (HCC) is the most common type of liver cancer and is still one of the most fatal cancers. Hence, it needs to identify always new putative markers to improve its diagnosis and prognosis. The selenium is an essential trace mineral implicated as a key factor in the early stage of cancer and exerts its biological function through the selenoproteins. In the last years our group has been studying the involvement of some selenoproteins in HCC. However, no many data are reported in literature about the correlation between HCC and the glutathione peroxidases (GPXs), both selenium and non selenium-containing GPXs. In this paper we have evaluated the GPX4 and GPX7 expression in some paraffin-embedded tissues from liver biopsy of patients with hepatitis C virus (HCV)-related cirrhosis and HCC by immunohistochemistry and RT-qPCR analysis. Our results evidenced that i) GPX4 and GPX7 had a statistically significant over-expression in HCC tissues compared to cirrhotic counterparts used as non tumor tissues, and ii) their expression was higher in grade III HCC tissues with respect to grade I-II samples. Therefore, we propose to use GPX4 and GPX7 as possible markers for improving HCC diagnosis/prognosis. PMID:26708178

Effects of selenium supplementation on four agricultural crops.

Science.gov (United States)

Carvalho, Kathleen M; Gallardo-Williams, Maria T; Benson, Robert F; Martin, Dean F

2003-01-29

Agricultural crops can be used either to remediate selenium-contaminated soils or to increase the daily selenium intake of consumers after soil supplementation using inorganic or organic selenium sources. In this study, four agricultural crops were examined for potential selenium enhancement. Soils containing tomato, strawberry, radish, and lettuce plants were supplemented with either an inorganic or an organic form of selenium. Two different soils, i.e., low Se and high Se containing, were also used. Statistically significant differences in appearance, fruit production, and fresh weights of the fruit produced were studied. Next, the amount of selenium retained in the edible fruits, nonedible plant, and soil for each was analyzed by acid digestion followed by hydride generation atomic absorption analysis. Finally, inhibition effects on the seeds of the agricultural plants were studied. The results show that supplementation with an inorganic form of selenium led to higher retention in the plants, with a maximum of 97.5% retained in the edible portion of lettuce plants.

Selenium and phosphorus interaction in pea (pisum sativum L.)

International Nuclear Information System (INIS)

Singh, Mahendra; Bhandari, D.K.

1975-01-01

The interaction of selenium and phosphorus on the dry matter yield and concentration and uptake of phosphorus, sulfur and selenium was studied in pea (Pisum sativnum) var. T 163. The fertilizer was tagged with P 32 . It was observed that increased concentration of applied selenium in soil decreased the dry matter yield and increased the concentration and uptake of total P, soil P and selenium in pea plants. Increased concentration of P alone increased dry matter yield, concentration and uptake of total, soil and fertilizer P and selenium which was beyond safe limits, and decreased concentration and uptake of sulphur. Selenium and phosphorus showed strong synergetic relationship by increasing the concentration of each other in plants while both showed antagonistic effect on the concentration of sulphur. Phosphorus compensated the toxic effect of selenium and improved the growth and dry matter yield of pea plants. The highest selenium concentration of 22.4 ppm was observed in 100 ppm phosphorus with 5 ppm selenium treated pots while lowest (0.10 ppm) in control. (author)

Does mercury vapor exposure increase urinary selenium excretion

Energy Technology Data Exchange (ETDEWEB)

Hongo, T; Suzuki, T; Himeno, S; Watanabe, C; Satoh, H; Shimada, Y

1985-01-01

It has been reported that an increase of urinary selenium excretion may occur as a result of mercury vapor exposure. However, experimental data regarding the interaction between mercury vapor and selenium have yielded ambiguous results about the retention and elimination of selenium due to mercury vapor exposure and the decrease of selenium excretion due to mercury in the form of mercuric mercury (Hg/sup 2 +/). In this study, the authors measured urinary mercury and selenium in workers with or without exposure to mercury vapor to determine whether or not urinary selenium excretion was increased as a result of mercury vapor exposure. Urine samples were collected from 141 workers, 71 men and 70 women, whose extent of exposure to mercury vapor varied according to their job sites. Workers were divided into five groups according to their urinary mercury levels. The mercury level in group I was less than 2.8 nmol/mmol creatinine which means that this group was mostly free from mercury exposure. The average age was almost identical among the groups. For both sexes, group V (with the highest urinary mercury level) had the lowest urinary selenium level, but one-way variance analysis (ANOVA) did not reveal any significant variations of urinary selenium with urinary mercury levels; however, a weak but significant negative correlation between mercury and selenium was found in men.

Post-discharge supplementation of vitamins and minerals for preterm neonates.

Science.gov (United States)

Dall'Agnola, Alberto; Beghini, Lorenzo

2009-10-01

Ninety percent of premature babies has nutritional deficiency at discharge. It is very important that not only carbohydrates, proteins, fats, but also mineral salts, and vitamins are in quantities and adequate quality according to the needs of the various scientific neonatal and nutrition programs so as to avoid any shortcomings or excess. The growth, neurodevelopmental outcome and quality of life depend on, among other factors, an adequate nutritional supply with essential nutrients including minerals. It is now recommended that all infants and children, including adolescents, have a minimum daily intake of 400 IU of vitamin D beginning soon after birth. The standard initial dose of vitamin K1 for full term infants (1.0 mg) may be too high for premature infants. The addition of folate and especially vitamin B-12 with formula feedings, provided an effective and nontoxic means of reducing anemia of prematurity. Several investigators have reported higher plasma concentrations of selenium and glutathione peroxidase in preterm infants fed with selenium-supplemented formula than in infants fed with unsupplemented formula.

Mercury and selenium levels, and selenium:mercury molar ratios of brain, muscle and other tissues in bluefish (Pomatomus saltatrix) from New Jersey, USA

Science.gov (United States)

Burger, Joanna; Jeitner, Christian; Donio, Mark; Pittfield, Taryn; Gochfeld, Michael

2015-01-01

A number of contaminants affect fish health, including mercury and selenium, and the selenium: mercury molar ratio. Recently the protective effects of selenium on methylmercury toxicity have been publicized, particularly for consumption of saltwater fish. Yet the relative ameliorating effects of selenium on toxicity within fish have not been examined, nor has the molar ratio in different tissues, (i.e. brain). We examined mercury and selenium levels in brain, kidney, liver, red and white muscle, and skin and scales in bluefish (Pomatomus saltatrix) from New Jersey to determine whether there were toxic levels of either metal, and we computed the selenium: mercury molar ratios by tissues. Total mercury averaged 0.32 ± 0.02 ppm wet weight in edible muscle and 0.09 ± 0.01 ppm in brain. Selenium concentration averaged 0.37 ± 0.03 in muscle and 0.36 ± 0.03 ppm in brain. There were significant differences in levels of mercury, selenium, and selenium: mercury molar ratios, among tissues. Mercury and selenium levels were correlated in kidney and skin/scales. Mercury levels were highest in kidney, intermediate in muscle and liver, and lowest in brain and skin/scales; selenium levels were also highest in kidney, intermediate in liver, and were an order of magnitude lower in the white muscle and brain. Mercury levels in muscle, kidney and skin/scales were positively correlated with fish size (length). Selenium levels in muscle, kidney and liver were positively correlated with fish length, but in brain; selenium levels were negatively correlated with fish length. The selenium: mercury molar ratio was negatively correlated with fish length for white muscle, liver, kidney, and brain, particularly for fish over 50 cm in length, suggesting that older fish experience less protective advantages of selenium against mercury toxicity than smaller fish, and that consumers of bluefish similarly receive less advantage from eating larger fish. PMID:23202378

Selenium nanoparticles: potential in cancer gene and drug delivery.

Science.gov (United States)

Maiyo, Fiona; Singh, Moganavelli

2017-05-01

In recent decades, colloidal selenium nanoparticles have emerged as exceptional selenium species with reported chemopreventative and therapeutic properties. This has sparked widespread interest in their use as a carrier of therapeutic agents with results displaying synergistic effects of selenium with its therapeutic cargo and improved anticancer activity. Functionalization remains a critical step in selenium nanoparticles' development for application in gene or drug delivery. In this review, we highlight recent developments in the synthesis and functionalization strategies of selenium nanoparticles used in cancer drug and gene delivery systems. We also provide an update of recent preclinical studies utilizing selenium nanoparticles in cancer therapeutics.

Glutathione S-transferases Y

African Journals Online (AJOL)

The effects of the non-substrate ligand rose-Bengal as well as the substrate ligands sulphobromophthalein and acrolein on the GSH peroxidase activity of these two iso-enzymes were also investigated. Depending on the ligand, the inhibition profiles of these two iso-enzymes when measured with either the peroxidase ...

The prospective protective effect of selenium nanoparticles against chromium-induced oxidative and cellular damage in rat thyroid

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Hassanin KMA

2013-05-01

Full Text Available Kamel MA Hassanin,1 Samraa H Abd El-Kawi,2 Khalid S Hashem1 1Department of Biochemistry, Faculty of Veterinary Medicine, 2Department of Histology, Faculty of Medicine, Beni-Suef University, Beni-Suef, Egypt Background: Nanotechnology has enabled researchers to synthesize nanosize particles that possess increased surface areas. Compared to conventional microparticles, it has resulted in increased interactions with biological targets. Objective: The objective of this study was to determine the protective ability of selenium nanoparticles against hexavalent chromium-induced thyrotoxicity. Design: Twenty male rats were used in the study, and arbitrarily assigned to four groups. Group 1 was the control group, and was given phosphate-buffered saline. Group 2 was the chromium-treated group and was given K2Cr2O7 60 µg/kg body weight intraperitoneally as a single dose on the third day of administration. Group 3 was the nano-selenium-treated group and was given selenium nanoparticles (size 3–20 nm 0.5 mg/kg body weight intraperitoneally daily for 5 consecutive days. Group 4 was the nano-selenium chromium-treated group, which received selenium nanoparticles for 5 days and a single dose of K2Cr2O7 on the third day of administration. Materials and methods: Blood samples were collected from rats for measuring thyroid hormones (free triiodothyronine [T3] and free thyroxine [T4] and oxidative and antioxidant parameters (malondialdehyde [MDA], reduced glutathione [GSH], catalase, and superoxide dismutase [SOD]. Upon dissection, thyroid glands were taken for histopathological examination by using paraffin preparations stained with hematoxylin and eosin (H&E and Masson’s trichrome. Immunohistochemical staining was performed for detecting cellular proliferation using Ki67 antibodies. Results: The present study shows that K2Cr2O7 has a toxic effect on the thyroid gland as a result of inducing a marked oxidative damage and release of reactive oxygen species

The association of oxidant-antioxidant status in patients with chronic renal failure.

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Aziz, Manal A; Majeed, Ghanim H; Diab, Kareem S; Al-Tamimi, Raid J

2016-01-01

Oxidative stress has been linked to disease progression, including chronic renal failure (CRF). The aim of the present study was to determine malondialdehyde (MDA) as a sign of lipid peroxidation, and to investigate the association between antioxidant activities and three trace elements, in 49 patients with CRF. The erythrocyte and plasma trace elements [selenium (Se), zinc (Zn), and copper (Cu)] and antioxidant defense levels were determined: glutathione peroxidase (GPx), superoxide dismutase (SOD), catalase (CAT), vitamins E and C. The obtained values were compared with 42 age- and sex-matched healthy controls. There were significantly lower mean values of plasma Se, GPx, vitamins E and C, erythrocyte Se, SOD and CAT levels in the patient group compared to the control group (p renal function.

Rationale and Design for the Peripartum Cardiomyopathy in Nigeria (PEACE Registry

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Kamilu M Karaye

2017-01-01

Full Text Available Background Nigeria probably has the highest burden of Peripartum Cardiomyopathy (PPCM in the world. The primary objective of this study is to describe the burden, ventricular remodelling and survival of PPCM in Nigeria. In the sub-studies, we aim to describe the relationship between selenium deficiency, oxidative stress and PPCM, the impact of sodium selenite supplementation on left ventricular reverse remodelling, change in New York Heart Association functional class and survival in PPCM, and the prevalence of selenium deficiency and its relationship with cardiac function in apparently healthy pregnant women. Methods The main registry and the first sub-study are prospective longitudinal studies, while the second sub-study is an open-label randomised trial. 36 study centres across Nigeria have been registered and 14 of them are already recruiting subjects. Patients will be recruited from June to December 2017 and followed up till December 2018. Serum selenium and glutathione peroxidase will be assayed at recruitment for consecutive PPCM patients with LV ejection fraction (LVEF <45% at 6 months postpartum. 200 subjects with selenium deficiency will be randomised into treatment (Selenium Selenite 200μg tablets daily for 3 months and no-treatment arms. In the second sub-study, 120 apparently healthy pregnant women (Controls will be recruited at 28-38 weeks of gestation and reviewed at 6-8 weeks postpartum, and their serum selenium and GPO levels will be measured at recruitment. Conclusions This will be the largest systematic evaluation of PPCM in Nigeria, and it is hoped that the information will assist in understanding the disease better and developing locally applicable interventions for the disease. ClinicalTrials.gov Identifier: NCT03081949

Preliminary Study on the Standard of Selenium Content in Agricultural Products

Institute of Scientific and Technical Information of China (English)

ZHANG Zhi-yuan; YOU Yong; GUO Qing-quan; WANG Yong-hong; DENG Shi-lin

2012-01-01

With the improvement of living standards, people pay more attention to the agricultural products with health protection function, and the selenium-rich agricultural products attract more and more consumers. The main biological role of selenium is to resist oxidation and inflammatory response, mainly focusing on resisting aging, preventing cardiovascular disease, protecting eyesight, counteracting or destroying the toxic properties, preventing cancer and thyroid disease. In most areas of China, there is a widespread shortage of selenium, thus producing selenium-rich agricultural products to provide natural selenium-rich health food to the areas in need of selenium, has gradually become a new hot spot of China’s health food industry, but high content of selenium in food is detrimental to human body, even leads to selenium intoxication, and artificially adding inorganic selenium is difficult to guarantee that the selenium content of agricultural products is not exceeded. According to human body’s daily demand for selenium in dietetics and the content of selenium in agricultural products in the Chinese food composition table, we put forward the recommendations on the standard of selenium in agricultural products, in order to provide the basis for China to formulate the health standard of selenium content in selenium-rich agricultural products.

Selenium deficiency and the effects of supplementation on preterm infants

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Renata Germano B. O. N. Freitas

2014-03-01

Full Text Available Objective: This study aimed to review the literature about blood concentrations of selenium associated with gestational age, feeding, supplementation and related clinical features in preterm infants. Data sources: Systematic review in the following databases: MEDLINE, PubMed, Google academics, SciELO. org, ScienceDirect (Elsevier and CINAHL-Plus with Full Text (EBSCO. Articles published up to January 2013 with the keywords "selenium deficiency", "selenium supplementation", "neonates", "infants", "newborn" and "preterm infants" were selected. Data synthesis: The studies reported that low blood selenium levels are associated with increased risk of respiratory diseases. Preterm infants, especially with low birth weight, presented lower selenium levels. Selenium deficiency has also been associated with the use of oral infant formula, enteral and parenteral nutrition (with or without selenium addition. The optimal dose and length of selenium supplementation is not well-established, since they are based only on age group and selenium ingestion by breastfed children. Furthermore, the clinical status of the infant affected by conditions that may increase oxidative stress, and consequently, selenium requirements is not taken into account. Conclusions: Prematurity and low birth weight can contribute to low blood selenium in premature infants. Selenium supplementation seems to minimize or prevent clinical complications caused by prematurity.

Selenium accumulation in lettuce germplasm

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Selenium (Se) is an essential micronutrient for animals and humans. Increasing Se content in food crops offers an effective approach to reduce the widespread selenium deficiency problem in many parts of the world. In this study, we evaluated thirty diverse accessions of lettuce (Lactuca sativa L.) f...

SELENIUM ACCUMULATION BY BASIL PLANTS (OCINUM BASILICUM L.

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N. A. Golubkina

2014-01-01

Full Text Available Selenium accumulation level in basil plants is investigated. A direct correlation between selenium concentration and essential oil content is demonstrated for basil and other aroma plants. No correlation is found between selenium and flavonoids.

A Study of Selenium in Leprosy

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Donna Partogi

2018-03-01

CONCLUSIONS: Selenium serum levels of patients with PB leprosy are higher than patients with MB leprosy, and high bacteriological index in patients with leprosy were correlated with low selenium serum levels.

Selenium's importance in regulatory issues regarding mercury

Energy Technology Data Exchange (ETDEWEB)

Raymond, Laura J.; Ralston, Nicholas V.C. [University of North Dakota Energy and Environmental Research Center, 15 North 23rd Street, Stop 9018, Grand Forks, ND 58202-9018 (United States)

2009-11-15

Current seafood safety and health risk assessment criteria use mercury concentrations as their sole basis. This unfortunate limitation omits consideration of selenium, an essential trace element that appears to be the primary molecular target of mercury toxicity. Although selenium has been recognized for decades as a means of counteracting mercury toxicity, its effects have often been overlooked or misunderstood. Experimental animal studies have demonstrated that increasing concentrations of selenium throughout the normal dietary range increasingly counteracts methylmercury toxicity. Dietary concentrations of selenium that are slightly less than the average amount present in ocean fish have been shown to completely prevent the onset of toxic symptoms of mercury toxicity, while animals fed lesser amounts of selenium rapidly sickened and died. Dietary selenium from a variety of sources including ocean fish such as tuna, swordfish, menhaden, and rockfish has been shown to counteract mercury toxicity. Since ocean fish are among the richest sources of dietary selenium, it is important to include selenium concentration measurements in future mercury risk assessments and seafood safety criteria. Mercury:selenium molar ratios in blood provide far more consistent and physiologically meaningful risk assessments. Comprehensive seafood safety criteria such as the Selenium Health Benefit Value enable clear differentiation between seafoods that are safe and those that are hazardous for human consumption. Use of parameters that integrate mercury-selenium relationships also make it easy to understand the differences between the findings of maternal mercury exposure studies that have been performed in New Zealand, the Faroes, the Seychelles, and the United Kingdom. Development of criteria for evaluating mercury-selenium interactions will enhance environmental protection and improve public safety. (author)

[Pharmaconutrition with parenteral selenium in sepsis].

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Langlois, P L; de Oliveira Figliolino, L F; Hardy, G; Manzanares, W