Dietary linseed oil supplemented with organic selenium improved the fatty acid nutritional profile, muscular selenium deposition, water retention, and tenderness of fresh pork.

PubMed

Jiang, Jiang; Tang, Xinyue; Xue, Yan; Lin, Gang; Xiong, Youling L

2017-09-01

Cross-bred pigs were fed a control diet (with 0.3ppm sodium selenite and 1.5% soybean oil) or organic selenium diets (0.3ppm Se-Yeast with 1.5% soybean or linseed oil) to investigate nutrient supplement effects on meat quality and oxidative stability. The organic selenium diets increased muscular selenium content up to 54%, and linseed oil increased n-3 fatty acids two-fold while lowering the n-6/n-3 fatty acid ratio from 13.9 to 5.9 over the selenite control diet (P<0.05). Organic selenium yeast treatments with linseed oil reduced pork drip loss by 58-74% when compared with diets with soybean oil. Lightness of fresh pork was slightly less for organic selenium groups than inorganic (P<0.05), but redness was mostly similar. Lipid oxidation (TBARS) and protein oxidation (sulfhydryl) during meat storage (4°C up to 6days) showed no appreciable difference (P>0.05) between diets, in agreement with the lack of notable difference in endogenous antioxidant enzyme activity between these meat groups. Copyright © 2017 Elsevier Ltd. All rights reserved.

Both Selenium Deficiency and Modest Selenium Supplementation Lead to Myocardial Fibrosis in Mice via Effects on Redox-Methylation Balance

PubMed Central

Metes-Kosik, Nicole; Luptak, Ivan; DiBello, Patricia M.; Handy, Diane E.; Tang, Shiow-Shih; Zhi, Hui; Qin, Fuzhong; Jacobsen, Donald W.; Loscalzo, Joseph; Joseph, Jacob

2013-01-01

Scope Selenium has complex effects in vivo on multiple homeostatic mechanisms such as redox balance, methylation balance, and epigenesis, via its interaction with the methionine-homocysteine cycle. In this study, we examined the hypothesis that selenium status would modulate both redox and methylation balance and thereby modulate myocardial structure and function. Methods and Results We examined the effects of selenium deficient (<0.025 mg/kg), control (0.15 mg/kg), and selenium supplemented (0.5 mg/kg) diets on myocardial histology, biochemistry and function in adult C57/BL6 mice. Selenium deficiency led to reactive myocardial fibrosis and systolic dysfunction accompanied by increased myocardial oxidant stress. Selenium supplementation significantly reduced methylation potential, DNA methyltransferase activity and DNA methylation. In mice fed the supplemented diet, inspite of lower oxidant stress, myocardial matrix gene expression was significantly altered resulting in reactive myocardial fibrosis and diastolic dysfunction in the absence of myocardial hypertrophy. Conclusions Our results indicate that both selenium deficiency and modest selenium supplementation leads to a similar phenotype of abnormal myocardial matrix remodeling and dysfunction in the normal heart. The crucial role selenium plays in maintaining the balance between redox and methylation pathways needs to be taken into account while optimizing selenium status for prevention and treatment of heart failure. PMID:23097236

Risk of chronic low-dose selenium overexposure in humans: insights from epidemiology and biochemistry.

PubMed

Vinceti, Marco; Maraldi, Tullia; Bergomi, Margherita; Malagoli, Carlotta

2009-01-01

The latest developments of epidemiologic and biochemical research suggest that current upper limits of intake for dietary selenium and for overall selenium exposure may be inadequate to protect human health. In particular, recent experimental and observational prospective studies indicate a diabetogenic effect of selenium at unexpectedly low levels of intake. Experimental evidence from laboratory studies and veterinary medicine appears to confirm previous epidemiologic observations that selenium overexposure is associated with an increased risk of amyotrophic lateral sclerosis, and a recent large trial indicated no beneficial effect in preventing prostate cancer. Moreover, the pro-oxidant properties of selenium species and the observation that the selenium-containing enzymes glutathione peroxidases are induced by oxidative stress imply that the increase in enzymatic activity induced by this metalloid may represent at least in part a compensatory response. Taken together, the data indicate that the upper safe limit of organic and inorganic selenium intake in humans may be lower than has been thought and that low-dose chronic overexposure to selenium may be considerably more widespread than supposed.

The influence of selenium status on body composition, oxidative DNA damage and total antioxidant capacity in newly diagnosed type 2 diabetes mellitus: A case-control study.

PubMed

Othman, Fatimah Binti; Mohamed, Hamid Jan Bin Jan; Sirajudeen, K N S; Noh, Mohd Fairulnizal B Md; Rajab, Nor Fadilah

2017-09-01

Selenium is involved in the complex system of defense against oxidative stress in diabetes through its biological function of selenoproteins and the antioxidant enzyme. A case-control study was carried out to determine the association of plasma selenium with oxidative stress and body composition status presented in Type 2 Diabetes Mellitus (T2DM) patient and healthy control. This study involved 82 newly diagnosed T2DM patients and 82 healthy controls. Plasma selenium status was determined with Graphite Furnace Atomic Absorption Spectrometry. Body Mass Index, total body fat and visceral fat was assessed for body composition using Body Composition Analyzer (TANITA). Oxidative DNA damage and total antioxidant capacity were determined for oxidative stress biomarker status. In age, gender and BMI adjustment, no significant difference of plasma selenium level between T2DM and healthy controls was observed. There was as a significant difference of Oxidative DNA damage and total antioxidant capacity between T2DM patients and healthy controls with tail DNA% 20.62 [95% CI: 19.71,21.49] (T2DM), 17.67 [95% CI: 16.87,18.56] (control); log tail moment 0.41[95% CI: 0.30,0.52] (T2DM), 0.41[95% CI: 0.30,0.52] (control); total antioxidant capacity 0.56 [95% CI: 0.54,0.58] (T2DM), 0.60 [95% CI: 0.57,0.62] (control). Waist circumference, BMI, visceral fat, body fat and oxidative DNA damage in the T2DM group were significantly lower in the first plasma selenium tertile (38.65-80.90μg/L) compared to the second (80.91-98.20μg/L) and the third selenium tertiles (98.21-158.20μg/L). A similar trend, but not statistically significant, was observed in the control group. Copyright © 2016 Elsevier GmbH. All rights reserved.

Both selenium deficiency and modest selenium supplementation lead to myocardial fibrosis in mice via effects on redox-methylation balance.

PubMed

Metes-Kosik, Nicole; Luptak, Ivan; Dibello, Patricia M; Handy, Diane E; Tang, Shiow-Shih; Zhi, Hui; Qin, Fuzhong; Jacobsen, Donald W; Loscalzo, Joseph; Joseph, Jacob

2012-12-01

Selenium has complex effects in vivo on multiple homeostatic mechanisms such as redox balance, methylation balance, and epigenesis, via its interaction with the methionine-homocysteine cycle. In this study, we examined the hypothesis that selenium status would modulate both redox and methylation balance and thereby modulate myocardial structure and function. We examined the effects of selenium-deficient (<0.025 mg/kg), control (0.15 mg/kg), and selenium-supplemented (0.5 mg/kg) diets on myocardial histology, biochemistry and function in adult C57/BL6 mice. Selenium deficiency led to reactive myocardial fibrosis and systolic dysfunction accompanied by increased myocardial oxidant stress. Selenium supplementation significantly reduced methylation potential, DNA methyltransferase activity and DNA methylation. In mice fed the supplemented diet, inspite of lower oxidant stress, myocardial matrix gene expression was significantly altered resulting in reactive myocardial fibrosis and diastolic dysfunction in the absence of myocardial hypertrophy. Our results indicate that both selenium deficiency and modest selenium supplementation leads to a similar phenotype of abnormal myocardial matrix remodeling and dysfunction in the normal heart. The crucial role selenium plays in maintaining the balance between redox and methylation pathways needs to be taken into account while optimizing selenium status for prevention and treatment of heart failure. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Antioxidant Actions of Selenium in Orbital Fibroblasts: A Basis for the Effects of Selenium in Graves' Orbitopathy.

PubMed

Rotondo Dottore, Giovanna; Leo, Marenza; Casini, Giamberto; Latrofa, Francesco; Cestari, Luca; Sellari-Franceschini, Stefano; Nardi, Marco; Vitti, Paolo; Marcocci, Claudio; Marinò, Michele

2017-02-01

A recent clinical trial has shown a beneficial effect of the antioxidant agent selenium in Graves' orbitopathy (GO). In order to shed light on the cellular mechanisms on which selenium may act, this study investigated its effects in cultured orbital fibroblasts. Primary cultures of orbital fibroblasts from six GO patients and six control subjects were established. Cells were treated with H 2 O 2 to induce oxidative stress, after pre-incubation with selenium-(methyl)selenocysteine (SeMCys). The following assays were performed: glutathione disulfide (GSSG), as a measure of oxidative stress, glutathione peroxidase (GPX) activity, cell proliferation, hyaluronic acid (HA), and pro-inflammatory cytokines. H 2 O 2 induced an increase in cell GSSG and fibroblast proliferation, which were reduced by SeMCys. Incubation of H 2 O 2 -treated cells with SeMCys was followed by an increase in glutathione peroxidase activity, one of the antioxidant enzymes into which selenium is incorporated. At the concentrations used (5 μM), H 2 O 2 did not significantly affect HA release, but it was reduced by SeMCys. H 2 O 2 determined an increase in endogenous cytokines involved in the response to oxidative stress and GO pathogenesis, namely tumor necrosis factor alpha, interleukin 1 beta, and interferon gamma. The increases in tumor necrosis factor alpha and interferon gamma were blocked by SeMCys. While the effects of SeMCys on oxidative stress and cytokines were similar in GO and control fibroblasts, they were exclusive to GO fibroblasts in terms of inhibiting proliferation and HA secretion. Selenium, in the form of SeMCys, abolishes some of the effects of oxidative stress in orbital fibroblasts, namely increased proliferation and secretion of pro-inflammatory cytokines. SeMCys reduces HA release in GO fibroblasts in a manner that seems at least in part independent from H 2 O 2 -induced oxidative stress. Some effects of SeMCys are specific for GO fibroblasts. These findings reveal some cellular mechanisms by which selenium may act in patients with GO.

Protective effects of selenium on acrylamide toxicity in the liver of the rat. Effects on the oxidative stress.

PubMed

Teodor, V; Cuciureanu, Magdalena; Filip, Cristiana; Zamosteanu, Nina; Cuciureanu, Rodica

2011-01-01

Acrylamide (AA), obtained for the first time by Moureu in Germany in 1893, is presently used as polyacrylamide in water treatment and wastewater treatment, paper and pulp processing, mineral processing, crude-oil production processes. Acrylamide is a chemical product formed when frying, roasting, grilling or baking carbohydrate-rich foods at temperatures above 120 degrees C. Acrylamide is thus found in a number of foods, such as bread, crisps, French fries and coffee. Tobacco smoking also generates substantial amounts of acrylamide. Acrylamide administration is associated with significant increase of oxidative stress parameters; acrylamide caused disturbances in the oxidative status and enzyme activities and the effect was pronounced with the high doses. This study investigates the effect of selenium (as sodium selenite and as a selenium dietary supplements--Celnium) on the oxidative stress in Wistar rats which received high doses of acrylamide. The administration of sodium selenite and selenium dietary supplements (Celnium) significantly increased GSH and GPx levels and decreased MDA compared to group which received only acrylamide. Our results show that sodium selenite and selenium dietary supplements (Celnium) can partially prevent the biochemical changes in the liver of the rats which received high doses of acrylamide.

Effects of Dietary Selenium and Vitamin E on Growth Performance, Meat Yield, and Selenium Content and Lipid Oxidation of Breast Meat of Broilers Reared Under Heat Stress.

PubMed

Habibian, Mahmood; Ghazi, Shahab; Moeini, Mohammad Mehdi

2016-01-01

This study was conducted using 360 broiler chickens to evaluate the effects of dietary vitamin E (0, 125, and 250 mg/kg), selenium (0, 0.5, and 1 mg/kg), or their different combinations on performance, meat yield, and selenium content and lipid oxidation of breast meat of broilers raised under either a thermoneutral (TN, 24 °C constant) or heat stress (HS, 24 to 37 °C cycling) condition. There was a reduction (P < 0.05) in body weight and feed intake and an increase (P < 0.05) in feed conversion ratio when broilers exposed to HS. In the overall period of the study (1 to 49 days), growth performance of TN broilers was not affected (P < 0.05) by vitamin E and selenium supplementation. However, under HS condition, broilers receiving 250 mg/kg vitamin E and 0.5 mg/kg selenium consumed more (P < 0.05) feed than that of broilers receiving 250 mg/kg vitamin E alone, but similar (P > 0.05) to that of broilers receiving 250 mg/kg vitamin E and 1 mg/kg selenium. The malondialdehyde (MDA) content of the breast meat was increased (P < 0.05), but its selenium content was decreased (P < 0.05) by exposure to HS. The breast meat selenium content was increased (P < 0.05) by selenium supplementation. The breast meat selenium content was decreased (P < 0.05) by supplementation of 250 mg/kg vitamin E to diet of TN birds. However, the breast meat selenium content was increased (P < 0.05) by supplementation of vitamin E under HS condition. The breast meat MDA content was not affected (P > 0.05) by dietary treatments under TN condition. However, the breast meat MDA content was decreased (P < 0.05) by both vitamin E and selenium supplementation under HS condition, and the lowest MDA content was observed in the breast meat of broilers receiving combination of 125 mg/kg vitamin E and 1 mg/kg selenium. The results showed that supplementation of selenium and vitamin E was capable of increasing the selenium content of the breast meat and could improve the lipid oxidation of the breast meat when broilers reared under HS condition.

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

PubMed

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 resistance to oxidation, our findings suggest a common mechanism for the use of selenium in biology. Copyright © 2017. Published by Elsevier Inc.

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

PubMed Central

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 common mechanism for the use of selenium in biology. PMID:28108278

Sodium selenite/selenium nanoparticles (SeNPs) protect cardiomyoblasts and zebrafish embryos against ethanol induced oxidative stress.

PubMed

Kalishwaralal, Kalimuthu; Jeyabharathi, Subhaschandrabose; Sundar, Krishnan; Muthukumaran, Azhaguchamy

2015-10-01

Alcoholic cardiomyopathy is the damage caused to the heart muscles due to high level of alcohol consumption resulting in enlargement and inflammation of the heart. Selenium is an important trace element that is beneficial to human health. Selenium protects the cells by preventing the formation of free radicals in the body. In the present study, protein mediated synthesis of SeNPs was investigated. Two different sizes of SeNPs were synthesized using BSA and keratin. The synthesized SeNPs were characterized by scanning electron microscopy (SEM) with elemental composition analysis Energy Dispersive X-ray spectroscopy(EDX) and X-ray diffraction (XRD). This study demonstrates the in vitro and in vivo antioxidative effects of sodium selenite and SeNPs. Further selenium and SeNPs were evaluated for their ability to protect against 1% ethanol induced oxidative stress in H9C2 cell line. The selenium and SeNPs were found to reduce the 1% ethanol-induced oxidative damage through scavenging intracellular reactive oxygen species. The selenium and SeNPs could also prevent pericardial edema induced ethanol treatment and reduced apoptosis and cell death in zebrafish embryos. The results indicate that selenium and SeNPs could potentially be used as an additive in alcoholic beverage industry to control the cardiomyopathy. Copyright © 2015 Elsevier GmbH. All rights reserved.

Selenium Nanoparticles for Stress-Resilient Fish and Livestock

NASA Astrophysics Data System (ADS)

Sarkar, Biplab; Bhattacharjee, Surajit; Daware, Akshay; Tribedi, Prosun; Krishnani, K. K.; Minhas, P. S.

2015-09-01

The fisheries and livestock sectors capture the highest share of protein-rich animal food and demonstrate accelerated growth as an agriculture subsidiary. Environmental pollution, climate change, as well as pathogenic invasions exert increasing stress impacts that lead the productivity momentum at a crossroads. Oxidative stress is the most common form of stress phenomenon responsible for the retardation of productivity in fisheries and livestock. Essential micronutrients play a determinant role in combating oxidative stress. Selenium, one of the essential micronutrients, appears as a potent antioxidant with reduced toxicity in its nanoscale form. In the present review, different methods of synthesis and characterization of nanoscale selenium have been discussed. The functional characterization of nano-selenium in terms of its effect on growth patterns, feed digestibility, and reproductive system has been discussed to elucidate the mechanism of action. Moreover, its anti-carcinogenic and antioxidant potentiality, antimicrobial and immunomodulatory efficacy, and fatty acid reduction in liver have been deciphered as the new phenomena of nano-selenium application. Biologically synthesized nano-selenium raises hope for pharmacologically enriched, naturally stable nanoscale selenium with high ecological viability. Hence, nano-selenium can be administered with commercial feeds for improvising stress resilience and productivity of fish and livestock.

Selenium Nanoparticles for Stress-Resilient Fish and Livestock.

PubMed

Sarkar, Biplab; Bhattacharjee, Surajit; Daware, Akshay; Tribedi, Prosun; Krishnani, K K; Minhas, P S

2015-12-01

The fisheries and livestock sectors capture the highest share of protein-rich animal food and demonstrate accelerated growth as an agriculture subsidiary. Environmental pollution, climate change, as well as pathogenic invasions exert increasing stress impacts that lead the productivity momentum at a crossroads. Oxidative stress is the most common form of stress phenomenon responsible for the retardation of productivity in fisheries and livestock. Essential micronutrients play a determinant role in combating oxidative stress. Selenium, one of the essential micronutrients, appears as a potent antioxidant with reduced toxicity in its nanoscale form. In the present review, different methods of synthesis and characterization of nanoscale selenium have been discussed. The functional characterization of nano-selenium in terms of its effect on growth patterns, feed digestibility, and reproductive system has been discussed to elucidate the mechanism of action. Moreover, its anti-carcinogenic and antioxidant potentiality, antimicrobial and immunomodulatory efficacy, and fatty acid reduction in liver have been deciphered as the new phenomena of nano-selenium application. Biologically synthesized nano-selenium raises hope for pharmacologically enriched, naturally stable nanoscale selenium with high ecological viability. Hence, nano-selenium can be administered with commercial feeds for improvising stress resilience and productivity of fish and livestock.

Protective effects of meat from lambs on selenium nanoparticle supplemented diet in a mouse model of polycyclic aromatic hydrocarbon-induced immunotoxicity.

PubMed

Ungvári, Éva; Monori, István; Megyeri, Attila; Csiki, Zoltán; Prokisch, József; Sztrik, Attila; Jávor, András; Benkő, Ilona

2014-02-01

Increased environmental oxidative stress caused primarily by chemicals like polycyclic aromatic hydrocarbons, plays significant role in human diseases. A representative compound, 7,12-dimethylbenz(a)anthracene (DMBA), was used for modeling oxidative damages including the significant decrease of the antioxidant capacity of the blood. Selenium has antioxidant effects but with a narrow therapeutic window. In our current studies to avoid accidental overdose and toxicity selenium was given to meat-producing animals. The standard rodent diet of mice was replaced by meat from lambs either on standard or selenium-enriched diet. Selenium concentration of lamb meat was enhanced three times by nano-selenium administration and an increase in the antioxidant capacity of the blood of mice was measured after the indirect selenium supplementation. Protective effects were also observed against DMBA-induced immunotoxicity. Twice the amount of white blood cells and among them three times more phagocytes survived. Similarly, in their renewal system in bone marrow twice the amount of cells survived and regenerative capacity of granulopoiesis was four times higher than in control DMBA-damaged mice. Our findings suggest functional dietary benefits of lamb meat enriched with selenium by feeding lambs with nanoparticle selenium supplements. Copyright © 2013 Elsevier Ltd. All rights reserved.

Reproduction in eastern screech-owls fed selenium

USGS Publications Warehouse

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 < 0.05) relative to controls. Parents given 4.4 ppm selenium produced no malformed nestlings, but femur lengths of young were shorter (P = 0.015) than those of controls. Liver 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).

DNA damage and oxidative stress response to selenium yeast in the non-smoking individuals: a short-term supplementation trial with respect to GPX1 and SEPP1 polymorphism.

PubMed

Jablonska, E; Raimondi, S; Gromadzinska, J; Reszka, E; Wieczorek, E; Krol, M B; Smok-Pieniazek, A; Nocun, M; Stepnik, M; Socha, K; Borawska, M H; Wasowicz, W

2016-12-01

Selenium, both essential and toxic element, is considered to protect against cancer, though human supplementation trials have generated many inconsistent data. Genetic background may partially explain a great variability of the studies related to selenium and human health. The aim of this study was to assess whether functional polymorphisms within two selenoprotein-encoding genes modify the response to selenium at the level of oxidative stress, DNA damage, and mRNA expression, especially in the individuals with a relatively low selenium status. The trial involved 95 non-smoking individuals, stratified according to GPX1 rs1050450 and SEPP1 rs3877899 genotypes, and supplemented with selenium yeast (200 µg) for 6 weeks. Blood was collected at four time points, including 4 weeks of washout. After genotype stratification, the effect of GPX1 rs1050450 on lower GPx1 activity responsiveness was confirmed; however, in terms of DNA damage, we failed to indicate that individuals homozygous for variant allele may especially benefit from the increased selenium intake. Surprisingly, considering gene and time interaction, GPX1 polymorphism was observed to modify the level of DNA strand breaks during washout, showing a significant increase in GPX1 wild-type homozygotes. Regardless of the genotype, selenium supplementation was associated with a selectively suppressed selenoprotein mRNA expression and inconsistent changes in oxidative stress response, indicating for overlapped, antioxidant, and prooxidant effects. Intriguingly, DNA damage was not influenced by supplementation, but it was significantly increased during washout. These results point to an unclear relationship between selenium, genotype, and DNA damage.

Metamaterial 3D Gain Nanostructures Fabricated Using Direct Laser Writing

DTIC Science & Technology

2015-07-11

oxide (PdO) and selenium powder. To avoid aggregation of the nanoparticles oleic acid and trioctylphosphine were used as stabilizing agents. The...synthesis of the PbSe quantum dots. The precursors used are CdO (Cadmium oxide) and Selenium powder and as stabilizing agent oleic acid was used. The

Comparative effects of two different forms of selenium on oxidative stress biomarkers in healthy men: a randomized clinical trial.

PubMed

Richie, John P; Das, Arun; Calcagnotto, Ana M; Sinha, Raghu; Neidig, Wanda; Liao, Jiangang; Lengerich, Eugene J; Berg, Arthur; Hartman, Terryl J; Ciccarella, Amy; Baker, Aaron; Kaag, Matthew G; Goodin, Susan; DiPaola, Robert S; El-Bayoumy, Karam

2014-08-01

Epidemiologic and laboratory studies indicate that dietary selenium protects against prostate cancer. Results from clinical trials suggest that selenium-enriched yeast (SY) but not selenomethionine (SeMet) may be effective at reducing prostate cancer risk. Our objectives were to directly compare for the first time the effects of SeMet and SY on prostate cancer relevant biomarkers in men. We performed a randomized double blind, placebo-controlled trial of SY (200 or 285 μg/day) and SeMet (200 μg/day) administered for 9 months in 69 healthy men. Primary endpoints included blood levels of selenium-containing compounds and oxidative stress biomarkers [urine 8-hydroxy-2'-deoxyguanosine (8-OHdG) and 8-iso-prostaglandin-F2α (8-iso-PGF2α) and blood glutathione (GSH)]. Secondary endpoints included plasma glucose and PSA levels. Compliance was high in all groups (>95%). Plasma selenium levels were increased 93%, 54%, and 86% after 9 months in SeMet and low- and high-dose SY groups, respectively, and returned to baseline levels after a 3-month washout (P < 0.05). Levels of 8-OHdG and 8-iso-PGF2α were decreased 34% and 28%, respectively, after 9 months in the high-dose SY group (P < 0.05). These decreases were greatest in individuals with low baseline plasma levels of selenium (<127 ng/mL). No changes in serum PSA or blood glucose and GSH were observed. Overall, we showed for the first time, reductions in biomarkers of oxidative stress following supplementation with SY but not SeMet in healthy men. These findings suggest that selenium-containing compounds other than SeMet may account for the decrease in oxidative stress. ©2014 American Association for Cancer Research.

Comparative effects of two different forms of selenium on oxidative stress biomarkers in healthy men: a randomized clinical trial

PubMed Central

Richie, John P.; Das, Arun; Calcagnotto, Ana M.; Sinha, Raghu; Neidig, Wanda; Liao, Jiangang; Lengerich, Eugene J.; Berg, Arthur; Hartman, Terryl J.; Ciccarella, Amy; Baker, Aaron; Kaag, Matthew G.; Goodin, Susan; DiPaola, Robert S.; El-Bayoumy, Karam

2014-01-01

Epidemiological and laboratory studies indicate that dietary selenium protects against prostate cancer. Results from clinical trials suggest that selenium-enriched yeast (SY) but not selenomethionine (SeMet) may be effective at reducing prostate cancer risk. Our objectives were to directly compare for the first time the effects of SeMet and SY on prostate cancer relevant biomarkers in men. We performed a randomized double blind, placebo-controlled trial of SY (200 or 285 µg/day) and SeMet (200 µg/day) administered for 9 months in 69 healthy men. Primary endpoints included blood levels of selenium-containing compounds and oxidative stress biomarkers (urine 8-hydroxy-2’-deoxyguanosine [8-OHdG] and 8-iso-prostaglandin-F2α [8-iso-PGF2α] and blood glutathione [GSH]). Secondary endpoints included plasma glucose and PSA levels. Compliance was high in all groups (>95%). Plasma selenium levels were increased 93%, 54%, and 86% after 9 months in SeMet and low and high dose SY groups, respectively, and returned to baseline levels after a 3 month washout (P<0.05). Levels of 8-OHdG and 8-iso-PGF2α, were decreased 34% and 28%, respectively, after 9 months in the high dose SY group (P<0.05). These decreases were greatest in individuals with low baseline plasma levels of selenium (<127 ng/ml). No changes in serum PSA or blood glucose and GSH were observed. Overall, we showed for the first time, reductions in biomarkers of oxidative stress following supplementation with SY but not SeMet in healthy men. These findings suggest that selenium-containing compounds other than SeMet may account for the decrease in oxidative stress. PMID:24938534

Effect of sodium selenite on chosen anti- and pro-oxidative parameters in rats treated with lithium: A pilot study.

PubMed

Musik, Irena; Kocot, Joanna; Kiełczykowska, Małgorzata

2015-06-01

Selenium is an essential element of antioxidant properties. Lithium is widely used in medicine but its administration can cause numerous side effects including oxidative stress. The present study aimed at evaluating if sodium selenite could influence chosen anti- and pro-oxidant parameters in rats treated with lithium. The experiment was performed on four groups of Wistar rats: I (control) - treated with saline; II (Li) - treated with lithium (2.7 mgLi/kg b.w. as Li2CO3), III (Se) - treated with selenium (0.5 mgSe/kg b.w. as Na2SeO3), IV (Li+Se) - treated with Li2CO3 and Na2SeO3 together at the same doses as in group II and III, respectively. All treatments were performed by stomach tube for three weeks in form of water solutions. The following anti- and pro-oxidant parameters: total antioxidant status (TAS) value, catalase (CAT) activity, concentrations of ascorbic acid (AA) and malonyldialdehyde (MDA) in plasma as well as whole blood superoxide dismutase (SOD) and glutathione peroxidase (GPx) activities were measured. Selenium given alone markedly enhanced whole blood GPx and diminished plasma CAT vs. Lithium significantly decreased plasma CAT and slightly increased AA vs. Selenium co-administration restored these parameters to the values observed in control animals. Furthermore, selenium co-administration significantly increased GPx in Li-treated rats. All other parameters (TAS, SOD and MDA) were not affected by lithium and/or selenium. Further research seems to be warranted to decide if application of selenium as an adjuvant in lithium therapy is worth considering. Copyright © 2014 Institute of Pharmacology, Polish Academy of Sciences. Published by Elsevier Urban & Partner Sp. z o.o. All rights reserved.

Development of General Antisera for Trichothecanes

DTIC Science & Technology

1986-07-01

by treatment with selenium dioxide. The alcohol was further oxidized with pyridinium chlorochromate to the unsatu- rated ketone A-3. The ketone was...A-10. Thus, A-7 was oxidized as described above with pyridinIum chlorochromate and sodium acetate In methylene chloride to give A-8 In 72% yield...analog by treatment with selenium dioxide. Further oxidation with pyri inium chlorochromate yielded the unsaturated 8- ketone. This ketone was readily

Evaluation of selenium in dietary supplements using elemental speciation.

PubMed

Kubachka, Kevin M; Hanley, Traci; Mantha, Madhavi; Wilson, Robert A; Falconer, Travis M; Kassa, Zena; Oliveira, Aline; Landero, Julio; Caruso, Joseph

2017-03-01

Selenium-enriched dietary supplements containing various selenium compounds are readily available to consumers. To ensure proper selenium intake and consumer confidence, these dietary supplements must be safe and have accurate label claims. Varying properties among selenium species requires information beyond total selenium concentration to fully evaluate health risk/benefits A LC-ICP-MS method was developed and multiple extraction methods were implemented for targeted analysis of common "seleno-amino acids" and related oxidation products, selenate, selenite, and other species relatable to the quality and/or accuracy of the labeled selenium ingredients. Ultimately, a heated water extraction was applied to recover selenium species from non-selenized yeast supplements in capsule, tablet, and liquid forms. For selenized yeast supplements, inorganic selenium was monitored as a means of assessing selenium yeast quality. A variety of commercially available selenium supplements were evaluated and discrepancies between labeled ingredients and detected species were noted. Published by Elsevier Ltd.

Evaluation of selenium in dietary supplements using elemental speciation

PubMed Central

Kubachka, Kevin M.; Hanley, Traci; Mantha, Madhavi; Wilson, Robert A.; Falconer, Travis M.; Kassa, Zena; Oliveira, Aline; Landero, Julio; Caruso, Joseph

2016-01-01

Selenium-enriched dietary supplements containing various selenium compounds are readily available to consumers. To ensure proper selenium intake and consumer confidence, these dietary supplements must be safe and have accurate label claims. Varying properties among selenium species requires information beyond total selenium concentration to fully evaluate health risk/benefits A LC-ICP-MS method was developed and multiple extraction methods were implemented for targeted analysis of common “seleno-amino acids” and related oxidation products, selenate, selenite, and other species relatable to the quality and/or accuracy of the labeled selenium ingredients. Ultimately, a heated water extraction was applied to recover selenium species from non-selenized yeast supplements in capsule, tablet, and liquid forms. For selenized yeast supplements, inorganic selenium was monitored as a means of assessing selenium yeast quality. A variety of commercially available selenium supplements were evaluated and discrepancies between labeled ingredients and detected species were noted. PMID:27719915

Investigation of electrical noise in selenium-immersed thermistor bolometers

NASA Technical Reports Server (NTRS)

Tarpley, J. L.; Sarmiento, P. D.

1980-01-01

The selenium immersed, thermistor bolometer, IR detector failed due to spurious and escalating electrical noise outburst as a function of time at elevated temperatures during routine ground based testing in a space simulated environment. Spectrographic analysis of failed bolometers revealed selenium pure zones in the insulating selenium arsenic (Se-As) glass film which surrounds the active sintered Mn, Ni, Co oxide flake. The selenium pure film was identified as a potentially serious failure mechanism. Significant changes were instituted in the manufacturing techniques along with more stringent process controls which eliminated the selenium pure film and successfully produced 22study bolometers.

Selenium.

PubMed

Barceloux, D G

1999-01-01

The 4 natural oxidation states of selenium are elemental selenium (0), selenide (-2), selenite (+4), and selenate (+6). Inorganic selenate and selenite predominate in water whereas organic selenium compounds (selenomethionine, selenocysteine) are the major selenium species in cereal and in vegetables. The principal applications of selenium include the manufacture of ceramics, glass, photoelectric cells, pigments, rectifiers, semiconductors, and steel as well as use in photography, pharmaceutical production, and rubber vulcanizing. High concentrations of selenium in surface and in ground water usually occur in farm areas where irrigation water drains from soils with high selenium content (Kesterson Reservoir, California) or in lakes receiving condenser cooling water from coal-fired electric power plants (Belews Lake, North Carolina). For the general population, the primary pathway of exposure to selenium is food, followed by water and air. Both selenite and selenate possess substantial bioavailability. However, plants preferentially absorb selenates and convert them to organic compounds. Aquatic organisms (e.g., bivalves) can accumulate and magnify selenium in the food chain. Selenium is an essential component of glutathione peroxidase, which is an important enzyme for processes that protect lipids in polyunsaturated membranes from oxidative degradation. Inadequate concentrations of selenium in the Chinese diet account, at least in part, for the illness called Keshan disease. Selenium deficiency occurs in the geographic areas where Balkan nephropathy appears, but there is no direct evidence that selenium deficiency contributes to the development of this chronic, progressive kidney disease. Several lines of scientific inquiry suggest that an increased risk of cancer occurs as a result of low concentrations of selenium in the diet; however, insufficient evidence exists at the present time to recommend the use of selenium supplements for the prevention of cancer. The toxicity of most forms of selenium is low and the toxicity depends on the chemical form of selenium. The acute ingestion of selenious acid is almost invariably fatal, preceded by stupor, hypotension, and respiratory depression. Chronic selenium poisoning has been reported in China where changes in the hair and nails resulted from excessive environmental exposures to selenium. Garlic odor on the breath is an indication of excessive selenium exposure as a result of the expiration of dimethyl selenide. The US National Toxicology Program lists selenium sulfide as an animal carcinogen, but there is no evidence that other selenium compounds are carcinogens.

Selenium-containing allophycocyanin purified from selenium-enriched Spirulina platensis attenuates AAPH-induced oxidative stress in human erythrocytes through inhibition of ROS generation.

PubMed

Zhang, Haobin; Chen, Tianfeng; Jiang, Jie; Wong, Yum-Shing; Yang, Fang; Zheng, Wenjie

2011-08-24

Both selenium and allophycocyanin (APC) have been reported to show novel antioxidant activities. In this study, a fast protein liquid chromatographic method for purification of selenium-containing allophycocyanin (Se-APC) from selenium-enriched Spirulina platensis and the protective effect of Se-APC on 2,2'-azobis(2-amidinopropane) dihydrochloride (AAPH)-induced oxidative stress have been described. After fractionation by ammonium sulfate precipitation, and separation by DEAE-Sepharose ion-exchange and Sephacryl S-300 size exclusion chromatography, Se-APC with purity ratio (A652/A280) of 5.30 and Se concentration of 343.02 μg g(-1) protein was obtained. Se-APC exhibited stronger antioxidant activity than APC by scavenging ABTS (2,2'-azinobis-3-ethylbenzothiazolin-6-sulfonic acid) and AAPH free radicals. The oxidative hemolysis and morphological changes induced by AAPH in human erythrocytes were effectively reversed by coincubation with Se-APC. Lipid oxidation induced by the pro-oxidant agent cupric chloride in human plasma, as evaluated by formation of conjugated diene, was blocked by Se-APC. The accumulation of malondialdehyde, loss of reduced glutathione, and increase in enzyme activities of glutathione peroxidase and reductase induced by AAPH in human erythrocytes were effectively suppressed by Se-APC. Furthermore, Se-APC significantly prevented AAPH-induced intracellular reactive oxygen species (ROS) generation. Taken together, our results suggest that Se-APC demonstrates application potential in treatment of diseases in which excess production of ROS acts as a casual or contributory factor.

Blood selenium concentrations and enzyme activities related to glutathione metabolism in wild emperor geese

USGS Publications Warehouse

Franson, J. Christian; Hoffman, David J.; Schmutz, Joel A.

2002-01-01

In 1998, we collected blood samples from 63 emperor geese (Chen canagica) on their breeding grounds on the Yukon-Kuskokwim Delta (YKD) in western Alaska, USA. We studied the relationship between selenium concentrations in whole blood and the activities of glutathione peroxidase and glutathione reductase in plasma. Experimental studies have shown that plasma activities of these enzymes are useful biomarkers of selenium-induced oxidative stress, but little information is available on their relationship to selenium in the blood of wild birds. Adult female emperor geese incubating their eggs in mid-June had a higher mean concentration of selenium in their blood and a greater activity of glutathione peroxidase in their plasma than adult geese or goslings that were sampled during the adult flight feathermolting period in late July and early August. Glutathione peroxidase activity was positively correlated with the concentration of selenium in the blood of emperor geese, and the rate of increase relative to selenium was greater in goslings than in adults. The activity of glutathione reductase was greatest in the plasma of goslings and was greater in molting adults than incubating females but was not significantly correlated with selenium in the blood of adults or goslings. Incubating female emperor geese had high selenium concentrations in their blood, accompanied by increased glutathione peroxidase activity consistent with early oxidative stress. These findings indicate that further study of the effects of selenium exposure, particularly on reproductive success, is warranted in this species.

Development of Sediment Quality Values for Puget Sound. Volume 1.

DTIC Science & Technology

1986-09-01

62 cadmium CHROMIUM,63 chromium COPPER ,64 copper IRON ,65 iron LEAD ,66 lead MANGANES ,67 manganese NICKEL ,68 nickel SELENIUM,69 selenium SILVER ,70...BERYLLIU beryllium 67. CADMIUM cadmium 68. CHROMIUM chromium 69. COPPER copper 70. IRON iron 71. LEAD lead 72. MANGANES manganese 73. NICKEL nickel 74...they can also be strongly influenced by iron and manganese oxide and hydrous oxide surfaces (these phases can scavenge metals under oxidizing

Synthesis of selenium nano-composite (t-Se@PS) by surface initiated atom transfer radical polymerization.

PubMed

Wang, Michael C P; Gates, Byron D

2012-09-04

Selenium nanostructures, which are otherwise susceptible to oxidative damage, were encapsulated with a thin layer of polystyrene. The thin layer of polystyrene was grafted onto the surfaces of selenium by a surface initiated atom transfer radical polymerization reaction. These encapsulated nanostructures demonstrate an enhanced resistance towards corrosion.

[Assessment of efficiency of use of the developed supplement containing selenium on laboratory animals].

PubMed

Bazhenova, B A; Aslaliev, A D; Danilov, M B; Badmaeva, T M; Vtorushina, I A

2015-01-01

The article presents the results of a study of the effectiveness of wheat flour containing selenium in organic form. The organic form of trace element was achieved by transformation of selenium in selenium-methionine (Se-Met) at germination of wheat grains, moistened with a solution of sodium selenite. To determine the effectiveness of selenium- containing supplements experimental investigations were carried out on Long white rats with initial body weight 50 ± 2 g. The duration of the experiment was 30 days. The research model included four groups of animals: control group--animals were fed a complete vivarium diet; group 1--a model of selenium deficiency, which was achieved by feeding selenium-deficient food (grain growh in the Chita region of the Trans-Baikal Territory Zabaikalsky Krai); group 2--animals were administered selenium supplement in the form of enriched flour (0.025 µg Se per 50 g body weight of the animal) on the background of selenium-deficient diet; group 3--animals were treated with a high dose of selenium in the form of a solution of sodium selenite intragastrically through a tube (0.15 µg Se per 50 g body weight). Selenium-containing additive on the background of selenium-deficient diet had a positive impact on the appearance and behavior of animals, the body weight gain per head after 10 days in group 2 amounted to 47.9 g that was 4 fold larger than in rats of group 1. The study of selenium content showed that in the blood, liver, lungs and heart of rats treated with the additive on the background of selenium-deficient diet (group 2), selenium level did not differ from those in the control group and was within physiological norms. The experiment showed that selenium deficiency and rich in selenium rich diet has a significantly different effect on the studied parameters of oxidative-antioxidative status. The activity of blood glutathione peroxidase in animals of group 2 (did not differ from that in group 3) was almost 2 fold higher than in blood of control animals and was seven fold higher than that in blood of animals kept on selenium deficient diet (35.57 ± 3.36 µmol/g per 1 min) A similar dependence was established when studying the activity of glutathione reductase. It has been revealed thatthe oxidative-antioxidative status of animals from experimental groups 1 and 3 was lower than from control group and group 2. Thus, blood antioxidant activity in animals receiving diet with selenium deficiency and high dose of this trace element, was less than in the control group by 43.1 and 25.4%, respectively. Liver MDA level in animals kept on a diet with selenium deficiency exceeded the value of this indicator in the group 2 more than 1.5 fold (110.5 ± 10.70 vs. 72.5 ± 4.30 nmol/mg). When using selenium-containing supplement, this parameter decreased to the control level. In blood plasma of the animals of group 2 total antioxidant activity increased by about five times as compared with the indicators of animals kept on selenium-deficient diet, and was 25% higher than in control. Thus, the introduction of a selenium supplements in the deficient diet contributes to the development of endogenous antioxidants that suppress lipid oxidation. High biological effectiveness of supplements containing organic form of selenium has been proved.

Thioacetamide-induced cirrhosis in selenium-adequate mice displays rapid and persistent abnormity of hepatic selenoenzymes which are mute to selenium supplementation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang Jinsong; Wang Huali; Yu Hanqing

2007-10-01

Selenium reduction in cirrhosis is frequently reported. The known beneficial effect of selenium supplementation on cirrhosis is probably obtained from nutritionally selenium-deficient subjects. Whether selenium supplementation truly improves cirrhosis in general needs additional experimental investigation. Thioacetamide was used to induce cirrhosis in selenium-adequate and -deficient mice. Selenoenzyme activity and selenium content were measured and the influence of selenium supplementation was evaluated. In Se-adequate mice, thioacetamide-mediated rapid onset of hepatic oxidative stress resulted in an increase in thioredoxin reductase activity and a decrease in both glutathione peroxidase activity and selenium content. The inverse activity of selenoenzymes (i.e. TrxR activity goes upmore » and GPx activity goes down) was persistent and mute to selenium supplementation during the progress of cirrhosis; accordingly, cirrhosis was not improved by selenium supplementation in any period. On the other hand, selenium supplementation to selenium-deficient mice always more efficiently increased hepatic glutathione peroxidase activity and selenium content compared with those treated with thioacetamide, indicating that thioacetamide impairs the liver bioavailability of selenium. Although thioacetamide profoundly affects hepatic selenium status in selenium-adequate mice, selenium supplementation does not modify the changes. Selenium supplementation to cirrhotic subjects with a background of nutritional selenium deficiency can improve selenium status but cannot restore hepatic glutathione peroxidase and selenium to normal levels.« less

Selenium as a versatile center in fluorescence probe for the redox cycle between HClO oxidative stress and H2S repair.

PubMed

Lou, Zhangrong; Li, Peng; Han, Keli

2015-01-01

Selenium is a biologically important trace element and acts as an active center of glutathione peroxidase (GPx). GPx is the important antioxidant enzyme to protect organisms from oxidative damage via catalyzing the reaction between ROS and glutathione (GSH). Mimicking the oxidation-reduction cycles of the versatile selenium core in GPx, we can develop fluorescence probes to detect oxidation and reduction events in living systems. The cellular redox balance between hypochloric acid (HClO) and hydrogen sulfide (H2S) has broad implications in human health and diseases, such as Alzheimer's disease (AD). Therefore, to further investigate the roles of this redox balance and understand the pathogenesis of neurodegenerative diseases, it is necessary to detect the redox state between HClO and H2S in real time. We have developed a reversible fluorescence probe MPhSe-BOD for imaging of the redox cycle between HClO and H2S based on oxidation and reduction of selenide in living cells.

Selenium and Iron Oxide Nanocomposites for Magnetically-Targeted Anti-Cancer Applications.

PubMed

Hauksdóttir, Halla Laufey; Webster, Thomas J

2018-03-01

Iron oxide nanoparticles (IONP) are already well-established in the medical field due to their ability to improve contrast in magnetic resonance imaging (MRI) and for their external magnetic control in the body. Moreover, selenium has been shown to kill numerous cancer cells at lower concentrations that IONP (e.g., 1 μg/ml). Selenium is a trace mineral of growing interest in cancer treatment since it is an essential nutrient in the human body and can interfere with thiolcontaining proteins necessary for cancer cells to function. For the above reasons, the goal of this in vitro study was to combine the above chemistries for the first time to develop composite nano-vehicles for magnetically targeted cancer therapy. The suggested design was an IONP core, stabilized by chitosan and decorated with selenium. Two different types of IONP cores were produced. This was followed by different chitosan and selenium coating methods. The particles were characterized for size, shape, zeta potential and magnetic properties. Finally, the most promising products were tested for cancer killing properties on MB-231 breast cancer cells. Results of this pioneering study showed that the most promising iron-selenium nanocomposites consisted of an iron oxide core produced by thermal decomposition, followed by a silane ligand exchange, a chitosan coating and selenium decoration. The particles were 5-9 nm in diameter, with a zeta potential of 29.59 mV and magnetic properties of 35.932 emu/g. Moreover, the novel nanoparticles had concentration dependent cancer killing properties. Specifically, after just 1 day of incubation, breast cancer cell viability was reduced to 40.5% in the presence of 1 μg/ml of these composite nanoparticles (and statistically reduced at even 0.1 μg/ml), without using a chemotherapeutic pharmaceutical drug. This is a significant finding since neither chemotherapeutic pharmaceutical drugs, infrared stimulation, nor magnetism were used. In this manner, this study introduces a brand new composite nanoparticle consisting of iron oxide and selenium which should be further studied for a wide range of magnetically targeted anticancer applications.

Effects of selenium supplementation on glucose homeostasis, inflammation, and oxidative stress in gestational diabetes: Randomized, double-blind, placebo-controlled trial.

PubMed

Asemi, Zatollah; Jamilian, Mehri; Mesdaghinia, Elaheh; Esmaillzadeh, Ahmad

2015-10-01

To our knowledge, no reports are available indicating the effects of selenium supplementation on metabolic parameters, inflammatory factors, and oxidative stress in gestational diabetes mellitus (GDM). The aim of this study was to assess the effects of selenium supplementation on metabolic status in pregnant women with GDM who were not on oral hypoglycemic agents. This randomized, double-blind, placebo-controlled clinical trial was performed with 70 women with GDM. Patients were randomly assigned to receive either 200 μg selenium supplements as tablet (n = 35) or placebo (n = 35) for 6 wk from weeks 24 to 28 of gestation. Fasting plasma samples were taken at study baseline and after 6 wk of intervention to quantify related variables. Selenium supplementation, compared with placebo, resulted in a significant reduction in fasting plasma glucose (-10.5 ± 11.9 versus +4.5 ± 12.9 mg/dL; P < 0.001), serum insulin levels (-1.98 ± 11.25 versus +5.26 ± 9.33 μIU/mL; P = 0.005), homeostasis model of assessment (HOMA)-insulin resistance (-0.84 ± 2.76 versus +1.47 ± 2.46; P < 0.001) and a significant increase in quantitative insulin sensitivity check index (+0.008 ± 0.03 versus -0.01 ± 0.01; P = 0.009). Additionally, a significant decrease in serum high-sensitivity C-reactive protein (hs-CRP) levels (-791.8 ± 2271.8 versus +500.5 ± 2563.3 ng/mL; P = 0.02) was seen after the administration of selenium supplements compared with placebo. Additionally, we observed a significant elevation in plasma glutathione (+52.14 ± 58.31 versus -39.93 ± 153.52 μmol/L; P = 0.002) and a significant reduction in plasma malondialdehyde levels (-0.01 ± 0.36 versus +0.67 ± 1.90 μmol/L; P = 0.04) after consumption of selenium supplements compared with placebo. We did not find any significant effect of taking selenium supplements on HOMA β-cell function, lipid profiles, plasma nitric oxide, or total antioxidant capacity concentrations. Selenium supplementation in pregnant women with GDM demonstrated beneficial effects on glucose metabolism, hs-CRP levels, and biomarkers of oxidative stress. Copyright © 2015 Elsevier Inc. All rights reserved.

Elucidating the selenium and arsenic metabolic pathways following exposure to the non-hyperaccumulating Chlorophytum comosum, spider plant

PubMed Central

Afton, Scott E.; Catron, Brittany; Caruso, Joseph A.

2009-01-01

Although many studies have investigated the metabolism of selenium and arsenic in hyperaccumulating plants for phytoremediation purposes, few have explored non-hyperaccumulating plants as a model for general contaminant exposure to plants. In addition, the result of simultaneous supplementation with selenium and arsenic has not been investigated in plants. In this study, Chlorophytum comosum, commonly known as the spider plant, was used to investigate the metabolism of selenium and arsenic after single and simultaneous supplementation. Size exclusion and ion-pairing reversed phase liquid chromatography were coupled to an inductively coupled plasma mass spectrometer to obtain putative metabolic information of the selenium and arsenic species in C. comosum after a mild aqueous extraction. The chromatographic results depict that selenium and arsenic species were sequestered in the roots and generally conserved upon translocation to the leaves. The data suggest that selenium was directly absorbed by C. comosum roots when supplemented with SeVI, but a combination of passive and direct absorption occurred when supplemented with SeIV due to the partial oxidation of SeIV to SeVI in the rhizosphere. Higher molecular weight selenium species were more prevalent in the roots of plants supplemented with SeIV, but in the leaves of plants supplemented with SeVI due to an increased translocation rate. When supplemented as AsIII, arsenic is proposed to be passively absorbed as AsIII and partially oxidized to AsV in the plant root. Although total elemental analysis demonstrates a selenium and arsenic antagonism, a compound containing selenium and arsenic was not present in the general aqueous extract of the plant. PMID:19273464

Alcohol, gestation and breastfeeding: selenium as an antioxidant therapy.

PubMed

Ojeda, Ma Luisa; Nogales, Fatima; Vázquez, Beatriz; Delgado, Ma José; Murillo, Ma Luisa; Carreras, Olimpia

2009-01-01

The aim of this paper is to study the relationship between alcohol, selenium and oxidative stress in breastfeeding rat pups exposed to ethanol during gestation and lactation. We have also studied how a Se-supplemented diet among mothers could prevent different oxidative liver disorders in the pups. Pups of 21 days were randomized into four groups: control group (C), alcohol group (A), alcohol selenium group (AS) and control selenium group (CS). Alcohol was supplied to their mothers for 13 weeks (induction, reproduction, gestation and lactation periods). The selenium-supplemented diet contained 0.5 ppm as selenite. We determined serum and liver selenium by graphite-furnace atomic absorption spectrometry. We measured antioxidant enzyme activities: glutathione peroxidase (GPx), glutathione reductase (GR), catalase (CAT) and superoxide dismutase (SOD); and lipid peroxidation (TBARS) and protein carbonyl (PC) by a spectrophotometric method in the liver. In the liver of pups, exposure to ethanol provoked a decrease in selenium and GPx activity and an increase in GR and CAT activity, as well as in carbonyl groups in protein. A pups had higher Se levels and GPx activity in serum than C pups. Administering Se with alcohol balances the activities of scavenging enzymes and reduces peroxidation protein products. These results suggest that selenium could be effective in neutralizing the damage of ethanol consumption during gestation and lactation in pups since it repairs selenium levels in liver as well as the activity of scavenging enzymes and peroxidation protein products. In serum, Se also recovers GPx activity and increases the levels of Se that are available to other organs.

Selenium deficiency and the effects of supplementation on preterm infants

PubMed Central

Freitas, Renata Germano B. O. N.; Nogueira, Roberto José N.; Antonio, Maria Ângela R. G. M.; Barros-Filho, Antonio de Azevedo; Hessel, Gabriel

2014-01-01

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. PMID:24676200

Enhanced Adsorption of Selenium Ions from Aqueous Solution Using Iron Oxide Impregnated Carbon Nanotubes

PubMed Central

Bakather, Omer Y.; Khraisheh, Majeda; Nasser, Mustafa S.

2017-01-01

The aim of this research was to investigate the potential of raw and iron oxide impregnated carbon nanotubes (CNTs) as adsorbents for the removal of selenium (Se) ions from wastewater. The original and modified CNTs with different loadings of Fe2O3 nanoparticles were characterized using high resolution transmission electron microscopy (HRTEM), scanning electron microscopy (SEM), X-ray diffractometer (XRD), Brunauer, Emmett, and Teller (BET) surface area analyzer, thermogravimetric analysis (TGA), zeta potential, and energy dispersive X-ray spectroscopy (EDS). The adsorption parameters of the selenium ions from water using raw CNTs and iron oxide impregnated carbon nanotubes (CNT-Fe2O3) were optimized. Total removal of 1 ppm Se ions from water was achieved when 25 mg of CNTs impregnated with 20 wt.% of iron oxide nanoparticles is used. Freundlich and Langmuir isotherm models were used to study the nature of the adsorption process. Pseudo-first and pseudo-second-order models were employed to study the kinetics of selenium ions adsorption onto the surface of iron oxide impregnated CNTs. Maximum adsorption capacity of the Fe2O3 impregnated CNTs, predicted by Langmuir isotherm model, was found to be 111 mg/g. This new finding might revolutionize the adsorption treatment process and application by introducing a new type of nanoadsorbent that has super adsorption capacity towards Se ions. PMID:28555093

Total selenium and selenium species in irrigation drain inflows to the Salton Sea, California, April and July 2007

USGS Publications Warehouse

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.

Association of selenium status and blood glutathione concentrations in blacks and whites

PubMed Central

Richie, John P.; Muscat, Joshua E.; Ellison, Irina; Calcagnotto, Ana; Kleinman, Wayne; El-Bayoumy, Karam

2011-01-01

Selenium deficiency has been linked with increased cancer risk and, in some studies, selenium supplementation was protective against certain cancers. Previous studies suggest that selenium chemoprevention may involve reduced oxidative stress through enhanced glutathione (GSH). Our objectives were to examine the relationships between selenium and GSH in blood and modifying effects of race and sex in free living adults and individuals supplemented with selenium. Plasma selenium concentrations and free and bound GSH concentrations and γ-glutamyl cysteine ligase (GCL) activity in blood were measured in 336 healthy adults, (161 blacks, 175 whites). Plasma selenium and blood GSH were also measured in 36 healthy men from our previously conducted placebo-controlled trial of selenium-enriched yeast (247 μg/day for 9 months). In free-living adults, selenium concentrations were associated with increased blood GSH concentration and GCL activity (P<0.05). Further, selenium was significantly higher in whites than in blacks (P<0.01). After 9 months of supplementation, plasma selenium was increased 114% in whites and 50% in blacks (P<0.05) and blood GSH was increased 35% in whites (P<0.05) but was unchanged in blacks. These results indicate a direct association between selenium and GSH in blood of both free-living and selenium-supplemented individuals, with race being an important modifying factor. PMID:21462082

Mechanism of bio molecule stabilized selenium nanoparticles against oxidation process and Clostridium Botulinum.

PubMed

Tareq, Foysal Kabir; Fayzunnesa, Mst; Kabir, Md Shahariar; Nuzat, Musrat

2018-02-01

The bio molecules from plant leaf extract utilized in the preparation of selenium material at the nano scale. The selenium ion was reduced to selenium nanoparticles in the presence of molecule residue of the plant leaf extract. The bio molecule stabilized selenium nanoparticles were grown gradually in the reaction mixture. The selenium nanoparticles were characterized using atomic absorption spectroscopy, fourier transform inferred spectroscopy, X-ray diffraction, scanning electronic microscope and transmission electronic microscope. The selenium nanoparticles were synthesized successfully as the nano-crystalline pure hexagonal phase and the size range of 26-41 nm with spherical in shape. The activity and mechanism of nanoparticles suggested that the selenium nanoparticles are causes of leakage of reducing sugars and protein of pathogens membrane cell. The selenium nano are responsible for death and fully inhibited the microbial growth of pathogen. The bio molecule stabilized selenium nanoparticles were also investigated for the antioxidant agent. Selenium nanoparticles showed scavenging activity up to 94.48%. These results recommended that the advantages of using this method for synthesis of selenium nanoparticles with excellent antioxidant and antimicrobial mechanism and activity, which can be used as the antioxidant and antibiotic agent. Copyright © 2017 Elsevier Ltd. All rights reserved.

Effects of Copper and Selenium Supplementation on Performance and Lipid Metabolism in Confined Brangus Bulls

PubMed Central

Netto, Arlindo Saran; Zanetti, Marcus Antônio; Claro, Gustavo Ribeiro Del; de Melo, Mariza Pires; Vilela, Flávio Garcia; Correa, Lisia Bertonha

2014-01-01

Twenty-eight Brangus cattle were used to determine the effect of copper and selenium supplementation on performance, feed efficiency, composition of fatty acids in Longissimus dorsi (LD) muscle, and cholesterol concentration in serum and in LD muscle and enzymes activities, reduced glutathione (GSH) and oxidized glutathione (GSSG). The treatments were: i) Control, without copper (Cu) and selenium (Se) supplementation; ii) Se, 2 mg Se/kg of dry matter such as sodium selenite; iii) Cu, 40 mg Cu/kg of dry matter such as copper sulfate; iv) Se/Cu, 2 mg Se/kg of dry matter such as sodium selenite and 40 mg Cu/kg of dry matter such as copper sulfate. LD muscle fatty acid composition was not influenced by the treatments (p>0.05). The serum concentration of cholesterol was not influenced by the treatments (p>0.05), however, the concentration of cholesterol in LD was lower in cattle supplemented with copper and selenium (p<0.05). Oxidized glutathione and reduced glutathione increased (p<0.05) with Cu, Se and Se/Cu supplementation. The supplementation of copper (40 mg/kg DM) and selenium (2 mg/kg DM) altered the metabolism of lipids in confined Brangus cattle, through a decrease in cholesterol deposition in the LD, possibly by changing the ratio between reduced glutathione/oxidized glutathione. Copper and selenium supplementation improved animal performance and feed efficiency (p<0.05) when compared to the control group, providing advantages in the production system, while also benefiting consumers by reducing cholesterol concentration in the meat. PMID:25049978

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

PubMed

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.

Lignosulfonate-stabilized selenium nanoparticles and their deposition on spherical silica.

PubMed

Modrzejewska-Sikorska, Anna; Konował, Emilia; Klapiszewski, Łukasz; Nowaczyk, Grzegorz; Jurga, Stefan; Jesionowski, Teofil; Milczarek, Grzegorz

2017-10-01

We report a novel room-temperature synthesis of selenium nanoparticles, which for the first time uses lignosulfonate as a stabilizer. Various lignosulfonates obtained both from hardwood and softwood were tested. Selenium oxide was used as the precursor of zero-valent selenium. Three different reducers were tested - sodium borohydride, hydrazine and ascorbic acid - and the latter proved most effective in terms of the particle size and stability of the final colloid. The lignosulfonate-stabilized selenium nanoparticles had a negative zeta potential, dependent on pH, which for some lignosulfonates reached -50mV, indicating the excellent stability of the colloid. When spherical silica particles were introduced to the synthesis mixture, selenium nanoparticles were deposited on their surface. Additionally, star-like structures consisting of sharp selenium needles with silica cores were observed. After drying, the selenium-functionalized silica had a grey metallic hue. The method reported here is simple and cost-effective, and can be used for the preparation of large quantities of selenium colloids or the surface modification of other materials with selenium. Copyright © 2017 Elsevier B.V. All rights reserved.

Accumulation and metabolism of selenium by yeast cells.

PubMed

Kieliszek, Marek; Błażejak, Stanisław; Gientka, Iwona; Bzducha-Wróbel, Anna

2015-07-01

This paper examines the process of selenium bioaccumulation and selenium metabolism in yeast cells. Yeast cells can bind elements in ionic from the environment and permanently integrate them into their cellular structure. Up to now, Saccharomyces cerevisiae, Candida utilis, and Yarrowia lipolytica yeasts have been used primarily in biotechnological studies to evaluate binding of minerals. Yeast cells are able to bind selenium in the form of both organic and inorganic compounds. The process of bioaccumulation of selenium by microorganisms occurs through two mechanisms: extracellular binding by ligands of membrane assembly and intracellular accumulation associated with the transport of ions across the cytoplasmic membrane into the cell interior. During intracellular metabolism of selenium, oxidation, reduction, methylation, and selenoprotein synthesis processes are involved, as exemplified by detoxification processes that allow yeasts to survive under culture conditions involving the elevated selenium concentrations which were observed. Selenium yeasts represent probably the best absorbed form of this element. In turn, in terms of wide application, the inclusion of yeast with accumulated selenium may aid in lessening selenium deficiency in a diet.

A complex of antioxidant vitamins effectively inhibits free-radical oxidation of LDL phospholipids in blood plasma and membrane structures of the liver and myocardium.

PubMed

Konovalova, G G; Lisina, M O; Tikhaze, A K; Lankin, V Z

2003-02-01

Antioxidant effect of a complex preparation including antioxidant vitamins C, E, provitamin A and selenium was studied on the model of Cu(2+)-initiated free-radical oxidation of LDL isolated from human blood plasma. The antioxidant effect of combined administration of alpha-tocopherol+ascorbic acid and alpha-tocopherol+beta-carotene is far more pronounced that the antioxidant effect of individual components of these cocktails. Moreover, in the model system the combined action of all antioxidant components completely inhibited free-radical oxidation of LDL. A 30-day course of peroral administration of antioxidant vitamin cocktail and selenium to rats pronouncedly enhanced the antioxidant potential of liver and completely suppressed free-radical processes in the myocardium. It is suggested that preparations containing antioxidant vitamins and selenium can be perspective for prevention and complex therapy of atherosclerosis.

Complex of vitamins and antioxidants protects low-density lipoproteins in blood plasma from free radical oxidation and activates antioxidants enzymes in erythrocytes from patients with coronary heart disease.

PubMed

Konovalova, G G; Lankin, V Z; Tikhaze, A K; Nezhdanova, I B; Lisina, M O; Kukharchuk, V V

2003-08-01

We studied the effect of a complex containing antioxidant vitamins C and E, provitamin A, and antioxidant element selenium on the contents of primary (lipid peroxides) and secondary products (malonic dialdehyde) of free radical lipid oxidation in low-density lipoproteins isolated from the plasma of patients with coronary heart disease and hypercholesterolemia by means of preparative ultracentrifugation. Activity of key antioxidant enzymes in the blood was measured during treatment with the antioxidant preparation. Combination treatment with antioxidant vitamins and antioxidant element selenium sharply decreased the contents of primary and secondary free radical oxidation products in circulating low-density lipoproteins and increased activity of antioxidant enzymes in erythrocytes. Activities of superoxide dismutase and selenium-containing glutathione peroxidase increased 1 and 2 months after the start of therapy, respectively.

Evaluation of cytotoxicity and oxidative DNA damaging effects of di(2-ethylhexyl)-phthalate (DEHP) and mono(2-ethylhexyl)-phthalate (MEHP) on MA-10 Leydig cells and protection by selenium

DOE Office of Scientific and Technical Information (OSTI.GOV)

Erkekoglu, Pinar; Hacettepe University, Faculty of Pharmacy, Department of Toxicology, 06100 Ankara; Rachidi, Walid

2010-10-01

Di(2-ethylhexyl)-phthalate (DEHP) is the most abundantly used phthalate derivative, inevitable environmental exposure of which is suspected to contribute to the increasing incidence of testicular dysgenesis syndrome in humans. Oxidative stress and mitochondrial dysfunction in germ cells are suggested to contribute to phthalate-induced disruption of spermatogenesis in rodents, and Leydig cells are one of the main targets of phthalates' testicular toxicity. Selenium is known to be involved in the modulation of intracellular redox equilibrium, and plays a critical role in testis, sperm, and reproduction. This study was aimed to investigate the oxidative stress potential of DEHP and its consequences in testicularmore » cells, and examine the possible protective effects of selenium using the MA-10 mouse Leydig tumor cell line as a model. In the presence and absence of selenium compounds [30 nM sodium selenite (SS), and 10 {mu}M selenomethionine (SM)], the effects of exposure to DEHP and its main metabolite mono(2-ethylhexyl)-phthalate (MEHP) on the cell viability, enzymatic and non-enzymatic antioxidant status, ROS production, p53 expression, and DNA damage by alkaline Comet assay were investigated. The overall results of this study demonstrated the cytotoxicity and genotoxicity potential of DEHP, where MEHP was found to be more potent than the parent compound. SS and SM produced almost the same level of protection against antioxidant status modifying effects, ROS and p53 inducing potentials, and DNA damaging effects of the two phthalate derivatives. It was thus shown that DEHP produced oxidative stress in MA-10 cells, and selenium supplementation appeared to be an effective redox regulator in the experimental conditions used in this study, emphasizing the critical importance of the appropriate selenium status.« less

Immobilization of selenate by iron in aqueous solution under anoxic conditions and the influence of uranyl

NASA Astrophysics Data System (ADS)

Puranen, Anders; Jonsson, Mats; Dähn, Rainer; Cui, Daqing

2009-08-01

In proposed high level radioactive waste repositories a large part of the spent nuclear fuel (SNF) canisters are commonly composed of iron. Selenium is present in spent nuclear fuel as a long lived fission product. This study investigates the influence of iron on the uptake of dissolved selenium in the form of selenate and the effect of the presence of dissolved uranyl on the above interaction of selenate. The iron oxide, and selenium speciation on the surfaces was investigated by Raman spectroscopy. X-ray Absorption Spectroscopy was used to determine the oxidation state of the selenium and uranium on the surfaces. Under the simulated groundwater conditions (10 mM NaCl, 2 mM NaHCO 3, <0.1 ppm O 2) the immobilized selenate was found to be reduced to oxidation states close to zero or lower and uranyl was found to be largely reduced to U(IV). The near simultaneous reduction of uranyl was found to greatly enhance the rate of selenate reduction. These findings suggest that the presence of uranyl being reduced by an iron surface could substantially enhance the rate of reduction of selenate under anoxic conditions relevant for a repository.

Protective effects of selenium on fluoride induced alterations in certain enzymes in brain of mice.

PubMed

Reddy, K Pratap; Sailaja, G; Krishnaiah, Chirumari

2009-09-01

This study reports the protective effects of selenium on fluoride induced alterations in the activities of pro-oxidative (xanthine oxidase (XOD), lipid peroxidation (LPO) free radical scavenging, [catalase, superoxide dismutase (SOD), glutathione-s-transferase (GST), glutathione peroxidase (GPX), glutathione reductase (GR), glutathione) and metabolic (glucose-6-phosphate dehydrogenase, alanine amino transferase (ALAT), aspartate aminotransferase (AAT), creatine phosphokinase (CPK), acid phosphatase (AP), alkaline phosphatase (ALP)] enzymes along with fluoride and selenium levels in brain of mice. Animals were divided into control, NaF treated group (20 mg kg(-1) body wt.(-1) intraperitonial) and Selenium+NaF treated group (sodium selenite, 5 microg of selenium/0.2 ml distilled water kg(-1) body wt.(-1) day) and were maintained for 14 days on respective treatments. The decreased bodyweight (-11.35%) as well as organosomatic index (-15.1%) of brain in NaF group were recovered in treatment of selenium along with NaF. The increased accumulation of fluoride (32.1%) in brain observed in NaF treated group compared to control was diminished in selenium+NaF treated group. Selenium levels (3.03%) increased in selenium+NaF treated group in compared to decrement in NaF treatment. The SOD (-16.6%), Catalase (-21.5%), GST(-13.72%), GPX (-19.16%), GR (-44.97%) activities and Glutathione (-23%) content in NaF treated group were decreased significantly compared to controls, which were significantly (p < 0.01) recovered in selenium+NaF group. Increased XOD (10.85%) and LPO (8.61%) levels observed in brain of NaF treated mice were reversed with selenium treatment. Glucose-6-phosphate dehydrogenase (-46.98%), ALAT (-10.44%), AAT (-10.21%), CPK (-27.98%) were decreased and alkaline phosphatase (10.6%), acid phosphatase (24.09%) increased in brain of mice after administration of NaF. All metabolic enzymes were significantly (p < 0.01) reversed after administration of selenium to the NaF treated group. Thus, the adverse effects of NaF on oxidative and metabolic enzymes of brain were reversible with ameliorative action of selenium supplementation. As evident in this study the antioxidative nature of selenium coupled with its reversal effect on metabolic enzymes in brain of mice treated with fluoride suggests its use as antidote agent against fluorosis.

Selenate reduction to elemental selenium by anaerobic bacteria in sediments and culture: biogeochemical significance of a novel, sulfate-independent respiration

USGS Publications Warehouse

Oremland, Ronald S.; Hollibaugh, James T.; Maest, Ann S.; Presser, Theresa S.; Miller, Laurence G.; Culbertson, Charles W.

1989-01-01

Interstitial water profiles of SeO42−, SeO32−, SO42−, and Cl− in anoxic sediments indicated removal of the seleno-oxyanions by a near-surface process unrelated to sulfate reduction. In sediment slurry experiments, a complete reductive removal of SeO42− occurred under anaerobic conditions, was more rapid with H2 or acetate, and was inhibited by O2, NO3−, MnO2, or autoclaving but not by SO42− or FeOOH. Oxidation of acetate in sediments could be coupled to selenate but not to molybdate. Reduction of selenate to elemental selenium was determined to be the mechanism for loss from solution. Selenate reduction was inhibited by tungstate and chromate but not by molybdate. A small quantity of the elemental selenium precipitated into sediments from solution could be resolublized by oxidation with either nitrate or FeOOH, but not with MnO2. A bacterium isolated from estuarine sediments demonstrated selenate-dependent growth on acetate, forming elemental selenium and carbon dioxide as respiratory end products. These results indicate that dissimilatory selenate reduction to elemental selenium is the major sink for selenium oxyanions in anoxic sediments. In addition, they suggest application as a treatment process for removing selenium oxyanions from wastewaters and also offer an explanation for the presence of selenite in oxic waters.

[Selenium metabolism in patients with severe multiple trauma].

PubMed

Zaĭnudinov, Z M; Shabanov, A K; Zorin, S N; Kuzovlev, A N; Mal'tsev, G Iu; Azarov, Ia B; Vorozhko, I V; Grebenchikov, O A

2014-01-01

To define a relation between the selenium level and the risk of the development of nosocomial pneumonia in patients with severe multiple trauma depending on the trauma severity and the volume of blood loss. We measured serum selenium concentration in 40 patients with severe multiple trauma. The ISS score was used to estimate the trauma severity. Patients were divided into 2 groups: group I--25 patients without pneumonia, group II--15 patients with pneumonia. The volume of blood loss was estimated in each group. The oxidative stress was estimated by means of the antioxidant index. For selected groups the significant difference (P < 0.05) in the volume of blood loss was detected. It was shown the significant decrease of selenium concentration (P < 0.05) in both groups in comparison with control for all testing time points (the 6-12 hrs, 24 hrs, 3 and 5-7 days). The mean of selenium concentration in group II was significantly lower in comparison to the group I. A significant difference of selenium concentrations (P < 0.05) between groups were detected on the 6-12 hrs and day 3 from the trauma onset. The antioxidant index was significantly lower in the group II within the 6-12 hrs, 12-24 hrs and 5-7 days (P < 0.05) in comparison to group I. The severe multiple trauma and severe blood loss lead to a selenium deficiency in the blood serum starting with the first hours from the trauma onset, which leads to the critical level of selenium concentration by the Ist day's end after trauma. It also leads to a pronounced oxidative stress that is reflected in the antioxidant index dynamics. Thus serum selenium concentration may be included in the set of the early prognostic detectors to detect infectious pulmonary complications development at severe multiple trauma, and it could be the basis for the decision to take early prophylaxis using selenium medications.

Selenium and Human Health: Witnessing a Copernican Revolution?

PubMed

Jablonska, Ewa; Vinceti, Marco

2015-01-01

In humans, selenium was hypothesized to lower the risk of several chronic diseases, mainly due to the antioxidant activity of selenium-containing proteins. Recent epidemiologic and laboratory studies, however, are changing our perception of the biological effects of this nutritionally essential trace element. We reviewed the most recent epidemiologic and biochemical literature on selenium, synthesizing the findings from these studies into a unifying view. Randomized trials have shown that selenium did not protect against cancer and other chronic diseases, but even increased the risk of specific neoplasms such as advanced prostate cancer and skin cancer, in addition to type 2 diabetes. Biochemical studies indicate that selenium may exert a broad pattern of toxic effects at unexpectedly low concentrations. Furthermore, its upregulation of antioxidant proteins (selenium-dependent and selenium-independent) may be a manifestation of self-induced oxidative stress. In conclusion, toxic effects of selenium species occur at lower concentrations than previously believed. Those effects may include a large range of proteomic changes and adverse health effects in humans. Since the effects of environmental exposure to this element on human health still remain partially unknown, but are potentially serious, the toxicity of selenium exposure should be further investigated and considered as a public health priority.

Total selenium and selenium species in irrigation drain inflows to the Salton Sea, California, October 2007 and January 2008

USGS Publications Warehouse

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.

Total selenium and selenium species in irrigation drain inflows to the Salton Sea, California, April and July 2008

USGS Publications Warehouse

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.

Total selenium and selenium species in irrigation drain inflows to the Salton Sea, California, October 2008 and January 2009

USGS Publications Warehouse

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.

Selenistasis: Epistatic Effects of Selenium on Cardiovascular Phenotype

PubMed Central

Joseph, Jacob; Loscalzo, Joseph

2013-01-01

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. PMID:23434902

[Effect of treatment with selenium electrophoresis on biochemical indices in patients suffering from ischaemic cardiac disease with a stable stenocardia of tension].

PubMed

Kurtsikidze, I

2006-08-01

Disturbances in lipid metabolism, intensification of lipid peroxidize oxidation and functions of sympatho-adrenal system play an important role in the development and progressing of ischaemic cardiac disease. As a result of investigations it has been established that microelement--selenium has an antiatherogenic action and suppresses peroxidize oxidation of lipids. The effect of treatment with selenium electrophoresis in patients suffering from ischaemic cardiac disease with a stable stenocardia of tension has been studied. Total of 76 patients with ICS:SST of I-II functional classes (FC) have been investigated. It has been established that treatment with selenium electrophoresis provokes a reduction of overall cholesterol, triglycerides and beta-lipoproteins content in blood serum, as well as a decrease of cholesterol amount in beta-lipoproteins, lipoproteins of low and very low density and diene conjugates in blood serum and adrenaline and norepinephrine excretion with urine; increase of lipoprotein amount of high density in blood serum, activity of catalase and selenium excretion with urine. Above-said positive changes in biochemical data were more pronounced for the ICS:SST of the first FC.

Influence of HIV infection and the use of antiretroviral therapy on selenium and selenomethionine concentrations and antioxidant protection.

PubMed

Watanabe, Lígia Moriguchi; Barbosa Júnior, Fernando; Jordão, Alceu Afonso; Navarro, Anderson Marliere

2016-01-01

The aim of the present study was to evaluate whether HIV infection and antiretroviral therapy (ART) use are associated with oxidative stress, concentrations of selenium and selenomethionine, and antioxidant protection. Individuals were classified as HIV negatives: control group (CG; n = 40); HIV positives: group 1 (G1; taking ART for >5 y, n = 40) and group 2 (G2; taking ART for <5 y, n = 40). Plasma and erythrocyte selenium, selenomethionine, glutathione (GSH), glutathione peroxidase activity (GPX), and malondialdehyde (MDA) were evaluated. Selenium deficiency (plasma selenium 45 μg/L) was not observed in any of the participants, and plasma selenium in CG (69.4 μg/L) was lower than in G1 and G2 (88.4 and 72.5 μg/L, respectively). G1 and G2 showed higher concentrations of MDA and GPX and lower concentration of GSH than CG. Multiple linear regression analysis indicated an association of MDA, GPX, and GSH with HIV status. CG participants showed higher concentrations of selenomethionine than G1 and G2 individuals and we observed a significant negative correlation between the concentration of selenomethionine and the use of ART. Prolonged ART use seems to increase the selenium in plasma, but influences the reduction of selenomethionine. HIV infection was associated with increased oxidative stress and appears to affect in protective activity of GPX. Finally, more studies are required to further address the importance of selenium and selenometabolites in the pathogenesis of infection and metabolism of HIV-positive individuals in prolonged use of ART. Copyright © 2016 Elsevier Inc. All rights reserved.

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.

PubMed

Dong, Ruixia; Wang, Dongxu; Wang, Xiaoxiao; Zhang, Ke; Chen, Pingping; Yang, Chung S; Zhang, Jinsong

2016-12-01

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(P)H: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. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

Arsenic and selenium in microbial metabolism

USGS Publications Warehouse

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 concentrations in waters tributary to and in the vicinity of the Kesterson National Wildlife Refuge, Fresno and Merced counties, California

USGS Publications Warehouse

Presser, T.S.; Barnes, Ivan

1984-01-01

Analyses were made for selenium in waters and other materials of the Kesterson National Wildlife Refuge. Analyses were also made of source agricultural drainage waters from the San Luis Drain discharged into the refuge, and surrounding irrigation supply and return waters. Selenium concentrations range from 140 to 1 ,400 micrograms per liter (microgram/L) in irrigation drain waters supplied to the San Luis Drain. The selenium supplied to the Kesterson National Wildlife Refuge is to a small extent precipitated in sodium sulfate (thenardite) but a higher concentration was found in an alagal mat. Most other waters of the area contain less than detectable < 2 micrograms per liter concentrations of selenium. Oxidation of organic matter and reduction of selenate to selenite were found to be necessary for a quantitative analysis of total selenium. (USGS)

Hydrological and geochemical investigations of selenium behavior at Kesterson Reservoir

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zawislanski, P.T.; Tokunaga, T.K.; Benson, S.M.

1995-05-01

This report describes research relevant to selenium specification, fractionation, physical redistribution, reduction and oxidation, and spatial distribution as related to Kesterson Reservoir. The work was carried out by scientists and engineers from the Earth Sciences Division of the Lawrence Berkeley Laboratory over a two year period from October 1992 to September 1994. Much of the focus of these efforts was on the effects of two above-average rainfall years (1991/1992 and 1992/1993). These events marked a departure from the previous six years of drought conditions, under which oxidation of Se in the soil profile led to a marked increase in solublemore » Se. Evidence from the last two years show that much of the re-oxidized Se was once more reduced due to increased soil moisture content. Also, in areas of high hydraulic conductivity, major vertical displacement of selenium and other solutes due to rainfall infiltration was observed. Such observations underscore the dependence of the future of Se speciation and distribution on environmental conditions.« less

Selenium deficiency decreases antioxidative capacity and is detrimental to bone microarchitecture in mice

USDA-ARS?s Scientific Manuscript database

Selenium (Se), a chemical component of selenoproteins (such as glutathione peroxidases and thioredoxin reductase), plays a major role in cellular redox status and may have beneficial effects on bone health. The deficiency of Se has been linked to increased oxidative stress with increased levels of r...

Identification of a novel selenium-containing compound, selenoneine, as the predominant chemical form of organic selenium in the blood of bluefin tuna.

PubMed

Yamashita, Yumiko; Yamashita, Michiaki

2010-06-11

A novel selenium-containing compound having a selenium atom in the imidazole ring, 2-selenyl-N(alpha),N(alpha),N(alpha)-trimethyl-L-histidine, 3-(2-hydroseleno-1H-imidazol-5-yl)-2-(trimethylammonio)propanoate, was identified from the blood and other tissues of the bluefin tuna, Thunnus orientalis. The selenium-containing compound was purified from the tuna blood in several chromatographic steps. High resolution mass spectrometry and nuclear magnetic resonance spectroscopy showed that the exact mass of the [M+H](+) ion of the compound was 533.0562 and the molecular formula was C(18)H(29)N(6)O(4)Se(2). Its gross structure was assigned as the oxidized dimeric form of an ergothioneine selenium analog in which the sulfur of ergothioneine is replaced by selenium. Therefore, we named this novel selenium-containing compound "selenoneine." By speciation analysis of organic selenium compounds using liquid chromatography inductively coupled plasma mass spectrometry, selenoneine was found widely distributed in various tissues of the tuna, with the highest concentration in blood; mackerel blood contained similar levels. Selenoneine was measurable at 2-4 orders of magnitude lower concentration in a limited set of tissues from squid, tilapia, pig, and chicken. Quantitatively, selenoneine is the predominant form of organic selenium in tuna tissues.

[Spectrometric characteristics and underlying mechanisms of protective effects of selenium on Spirulina platensis against oxidative stress].

PubMed

Wu, Hua-lian; Chen, Tian-feng; Yin, Xi; Zheng, Wen-jie

2012-03-01

To investigate the possibility and the underlying mechanisms of sodium selenite as antagonist for oxidative stress, the authors examined the effects of pretreatment with selenium on the growth, morphology, spectrometric characteristics and content of reactive oxygen species (ROS) in Spirulina platensis (S. platensis) exposed to H2O2 stress for 24 h in the present study. The results showed that H2O2 induced obvious inhibition of growth and serious morphological damage. The intensity of absorbance peak at 440 nm increased, whereas the peaks at 620 and 680 nm decreased after exposed to H2O2. The emission and excitation spectrum of S. platensis decreased dramatically after H2O2 treatment, and the emission peak from phycocyanin exhibited blue-shift from 660 to 650 nm. The results of FTIR analysis showed that the positions of transmission peaks had no shift, but the relative intensity of characteristic bands from protein and polypeptides including amide I and amide II decreased. Furthermore, the intracellular ROS generation in S. platensis increased significantly in response to H2O2 treatment. In contrast, pretreatments of the cells with selenium for 24 h significantly prevented the H2O2-induced oxidative damages in a dose-dependent manner. Taken together, our results indicate that pretreatments with selenium could prevent ROS overproduction in S. platensis and improve its antioxidant ability. Moreover, selenium could also reduce the effects of free radicals on energy harvest and energy transfer in S. platensis that play vital roles in its photosynthesis.

Selenium levels in human breast carcinoma tissue are associated with a common polymorphism in the gene for SELENOP (Selenoprotein P).

PubMed

Ekoue, Dede N; Zaichick, Sofia; Valyi-Nagy, Klara; Picklo, Matthew; Lacher, Craig; Hoskins, Kent; Warso, Michael A; Bonini, Marcelo G; Diamond, Alan M

2017-01-01

Selenium supplementation of the diets of rodents has consistently been shown to suppress mammary carcinogenesis and some, albeit not all, human epidemiological studies have indicated an inverse association between selenium and breast cancer risk. In order to better understand the role selenium plays in breast cancer, 30 samples of tumor tissue were obtained from women with breast cancer and analyzed for selenium concentration, the levels of several selenium-containing proteins and the levels of the MnSOD anti-oxidant protein. Polymorphisms within the genes for these same proteins were determined from DNA isolated from the tissue samples. There was a wide range of selenium in these tissues, ranging from 24 to 854ng/gm. The selenium levels in the tissues were correlated to the genotype of the SELENOP selenium carrier protein, but not to other proteins whose levels have been reported to be responsive to selenium availability, including GPX1, SELENOF and SBP1. There was an association between a polymorphism in the gene for MnSOD and the levels of the encoded protein. These studies were the first to examine the relationship between selenium levels, genotypes and protein levels in human tissues. Furthermore, the obtained data provide evidence for the need to obtain data about the effects of selenium in breast cancer by examining samples from that particular tissue type. Copyright © 2016 The Authors. Published by Elsevier GmbH.. All rights reserved.

Pressure-Stabilized Tin Selenide Phase with an Unexpected Stoichiometry and a Predicted Superconducting State at Low Temperatures

NASA Astrophysics Data System (ADS)

Yu, Hulei; Lao, Wenxin; Wang, Lijuan; Li, Kuo; Chen, Yue

2017-03-01

Tin-selenium binary compounds are important semiconductors that have attracted much interest for thermoelectric and photovoltaic applications. As tin has a +2 or +4 oxidation state and selenium has an oxidation number of -2 , only SnSe and SnSe2 have been observed. In this work, we show that the chemical bonding between tin and selenium becomes counterintuitive under pressures. Combining evolutionary algorithms and density functional theory, a novel cubic tin-selenium compound with an unexpected stoichiometry 3 ∶4 has been predicted and further synthesized in laser-heated diamond anvil cell experiments. Different from the conventional SnSe and SnSe2 semiconductors, Sn3 Se4 is predicted to be metallic and exhibit a superconducting transition at low temperatures. Based on electron density and Bader charge analysis, we show that Sn3 Se4 has a mixed nature of chemical bonds. The successful synthesis of Sn3 Se4 paves the way for the discovery of other IV-VI compounds with nonconventional stoichiometries and novel properties.

Pressure-Stabilized Tin Selenide Phase with an Unexpected Stoichiometry and a Predicted Superconducting State at Low Temperatures.

PubMed

Yu, Hulei; Lao, Wenxin; Wang, Lijuan; Li, Kuo; Chen, Yue

2017-03-31

Tin-selenium binary compounds are important semiconductors that have attracted much interest for thermoelectric and photovoltaic applications. As tin has a +2 or +4 oxidation state and selenium has an oxidation number of -2, only SnSe and SnSe_{2} have been observed. In this work, we show that the chemical bonding between tin and selenium becomes counterintuitive under pressures. Combining evolutionary algorithms and density functional theory, a novel cubic tin-selenium compound with an unexpected stoichiometry 3∶4 has been predicted and further synthesized in laser-heated diamond anvil cell experiments. Different from the conventional SnSe and SnSe_{2} semiconductors, Sn_{3}Se_{4} is predicted to be metallic and exhibit a superconducting transition at low temperatures. Based on electron density and Bader charge analysis, we show that Sn_{3}Se_{4} has a mixed nature of chemical bonds. The successful synthesis of Sn_{3}Se_{4} paves the way for the discovery of other IV-VI compounds with nonconventional stoichiometries and novel properties.

The prospective protective effect of selenium nanoparticles against chromium-induced oxidative and cellular damage in rat thyroid.

PubMed

Hassanin, Kamel M A; Abd El-Kawi, Samraa H; Hashem, Khalid S

2013-01-01

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. The objective of this study was to determine the protective ability of selenium nanoparticles against hexavalent chromium-induced thyrotoxicity. 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. 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. 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. This was shown by the significant decrease in free T3 and T4 and GSH levels, which was accompanied by significant increases in catalase, SOD, and MDA in the chromium-treated group compared to the control group. Se nanoparticles have a protective effect on K2Cr2O7-induced thyroid damage, as a result of correcting the free T3 and T4 levels and GSH, catalase, SOD, and MDA compared to the K2Cr2O7-treated group. Administration of nano-selenium alone in the nano-selenium-treated group had no toxic effect on rats' thyroid compared to the control group. The biochemical results were confirmed by histopathological, immunohistochemical and pathomorphological studies.

Probing for the Activities of Arsenic and Selenium Metabolizing Microbes

NASA Astrophysics Data System (ADS)

Stolz, J. F.

2007-12-01

Microbial activities can directly impact the mobility and toxicity of arsenic and selenium in the environment. Arsenic is cycled through oxidation/reduction and methylation/demethylation reactions as part of resistance and respiratory processes. The requirement for selenium is primarily for incorporation into selenocysteine and its function in selenoenzymes. Selenium oxyanions can also serve as an electron acceptor in anaerobic respiration. Both culture and culture-independent methods have been developed to detect the presence and activity of organisms capable of arsenic and selenium transformations. Enrichment media have been successful at cultivating arsenate respiring bacteria from a variety of environments, however, both electron donor and the concentration of arsenic can exert strong selective pressure. Thus, the organisms in the enrichment culture may not be the dominant organisms in the environment. Culture-independent methods, including immunological approaches (e.g., polyclonal antibodies to ArrA) and PCR-based technologies, have also had mixed success. PCR-primers designed to amplify portions of genes involved in resistance (e.g., arsC, acr3), respiration (e.g., arrA), and oxidation (e.g., aoxB) have been useful in several environments. Applications include T-RFLP, rt-PCR, and DGGE analyses. Nevertheless, these primers do not work with certain organisms suggesting the existence of additional enzymes and pathways. Although the biosynthetic pathway (and the proteins involved) for selenocysteine has been described in detail, much less is known about selenium methylation, assimilation and respiration. Only one respiratory selenate reductase has been characterized and its close sequence identity with chlorate and perchlorate reductases has complicated efforts to design a functional probe. Thus many aspects of the biogeochemical cycle of selenium remains to be explored.

Determination of trace selenium by solid substrate-room temperature phosphorescence enhancing method based on potassium chlorate oxidizing phenyl hydrazine-1,2-dihydroxynaphthalene-3,6-disulfonic acid system.

PubMed

Liu, Jia-Ming; Cui, Xiao-Jie; Li, Lai-Ming; Fu, Geng-Min; Lin, Shao-Xian; Yang, Min-Lan; Xu, Mei-Ying; Wu, Zhi-Qun

2007-04-01

A new method for the determination of trace selenium based on solid substrate-room temperature phosphorimetry (SS-RTP) has been established. This method was based on the fact that in HCl-KCl buffer solution, potassium chlorate could oxidize phenyl hydrazine to form chloridize diazo-ion after being heated at 100 degrees C for 20 min, and then the diazo-ion reacted with 1,2-dihydroxynaphthalene-3,6-disulfonic acid to form red azo-compound which could emit strong room temperature phosphorescence (RTP) signal on filter paper. Selenium could catalyze potassium chlorate oxidizing the reaction between phenyl hydrazine and 1,2-dihydroxynaphthalene-3,6-disulfonic acid, which caused the sharp enhancement of SS-RTP. Under the optimum condition, the relationship between the phosphorescence emission intensity (DeltaIp) and the content of selenium obeyed Beer's law when the concentration of selenium is within the range of 1.60-320 fg spot-1 (or 0.0040-0.80 ng ml-1 with a sample volume of 0.4 microl). The regression equation of working curve can be expressed as DeltaIp=13.12+0.4839CSe(IV) (fg spot-1) (n=6), with correlation coefficient r=0.9991 and a detection limit of 0.28 fg spot-1 (corresponding to a concentration range of 7.0x10(-13) g ml-1 Se(IV), n=11). After 11-fold measurement, R.S.D. were 2.8 and 3.5% for the samples containing 0.0040 and 0.80 ng ml-1 of Se(IV), respectively. This accurate and sensitive method with good repeatability has been successfully applied to the determination of trace selenium in Chinese wolfberry and egg yolk with satisfactory results. The mechanism of the enhancement of phosphorescence was also discussed.

Determination of trace selenium by solid substrate-room temperature phosphorescence enhancing method based on potassium chlorate oxidizing phenyl hydrazine-1,2-dihydroxynaphthalene-3,6-disulfonic acid system

NASA Astrophysics Data System (ADS)

Liu, Jia-Ming; Cui, Xiao-Jie; Li, Lai-Ming; Fu, Geng-Min; Lin, Shao-Xian; Yang, Min-Lan; Xu, Mei-Ying; Wu, Zhi-Qun

2007-04-01

A new method for the determination of trace selenium based on solid substrate-room temperature phosphorimetry (SS-RTP) has been established. This method was based on the fact that in HCl-KCl buffer solution, potassium chlorate could oxidize phenyl hydrazine to form chloridize diazo-ion after being heated at 100 °C for 20 min, and then the diazo-ion reacted with 1,2-dihydroxynaphthalene-3,6-disulfonic acid to form red azo-compound which could emit strong room temperature phosphorescence (RTP) signal on filter paper. Selenium could catalyze potassium chlorate oxidizing the reaction between phenyl hydrazine and 1,2-dihydroxynaphthalene-3,6-disulfonic acid, which caused the sharp enhancement of SS-RTP. Under the optimum condition, the relationship between the phosphorescence emission intensity (Δ Ip) and the content of selenium obeyed Beer's law when the concentration of selenium is within the range of 1.60-320 fg spot -1 (or 0.0040-0.80 ng ml -1 with a sample volume of 0.4 μl). The regression equation of working curve can be expressed as Δ Ip = 13.12 + 0.4839 CSe(IV) (fg spot -1) ( n = 6), with correlation coefficient r = 0.9991 and a detection limit of 0.28 fg spot -1 (corresponding to a concentration range of 7.0 × 10 -13 g ml -1 Se(IV), n = 11). After 11-fold measurement, R.S.D. were 2.8 and 3.5% for the samples containing 0.0040 and 0.80 ng ml -1 of Se(IV), respectively. This accurate and sensitive method with good repeatability has been successfully applied to the determination of trace selenium in Chinese wolfberry and egg yolk with satisfactory results. The mechanism of the enhancement of phosphorescence was also discussed.

Microbial Transformations of Selenium Species of Relevance to Bioremediation

PubMed Central

Eswayah, Abdurrahman S.; Smith, Thomas J.

2016-01-01

Selenium species, particularly the oxyanions selenite (SeO32−) and selenate (SeO42−), are significant pollutants in the environment that leach from rocks and are released by anthropogenic activities. Selenium is also an essential micronutrient for organisms across the tree of life, including microorganisms and human beings, particularly because of its presence in the 21st genetically encoded amino acid, selenocysteine. Environmental microorganisms are known to be capable of a range of transformations of selenium species, including reduction, methylation, oxidation, and demethylation. Assimilatory reduction of selenium species is necessary for the synthesis of selenoproteins. Dissimilatory reduction of selenate is known to support the anaerobic respiration of a number of microorganisms, and the dissimilatory reduction of soluble selenate and selenite to nanoparticulate elemental selenium greatly reduces the toxicity and bioavailability of selenium and has a major role in bioremediation and potentially in the production of selenium nanospheres for technological applications. Also, microbial methylation after reduction of Se oxyanions is another potentially effective detoxification process if limitations with low reaction rates and capture of the volatile methylated selenium species can be overcome. This review discusses microbial transformations of different forms of Se in an environmental context, with special emphasis on bioremediation of Se pollution. PMID:27260359

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.

PubMed

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.

How to use the world's scarce selenium resources efficiently to increase the selenium concentration in food

PubMed Central

Haug, Anna; Graham, Robin D.; Christophersen, Olav A.; Lyons, Graham H.

2007-01-01

The world's rare selenium resources need to be managed carefully. Selenium is extracted as a by-product of copper mining and there are no deposits that can be mined for selenium alone. Selenium has unique properties as a semi-conductor, making it of special value to industry, but it is also an essential nutrient for humans and animals and may promote plant growth and quality. Selenium deficiency is regarded as a major health problem for 0.5 to 1 billion people worldwide, while an even larger number may consume less selenium than required for optimal protection against cancer, cardiovascular diseases and severe infectious diseases including HIV disease. Efficient recycling of selenium is difficult. Selenium is added in some commercial fertilizers, but only a small proportion is taken up by plants and much of the remainder is lost for future utilization. Large biofortification programmes with selenium added to commercial fertilizers may therefore be a fortification method that is too wasteful to be applied to large areas of our planet. Direct addition of selenium compounds to food (process fortification) can be undertaken by the food industry. If selenomethionine is added directly to food, however, oxidation due to heat processing needs to be avoided. New ways to biofortify food products are needed, and it is generally observed that there is less wastage if selenium is added late in the production chain rather than early. On these bases we have proposed adding selenium-enriched, sprouted cereal grain during food processing as an efficient way to introduce this nutrient into deficient diets. Selenium is a non-renewable resource. There is now an enormous wastage of selenium associated with large-scale mining and industrial processing. We recommend that this must be changed and that much of the selenium that is extracted should be stockpiled for use as a nutrient by future generations. PMID:18833333

Simultaneous removal of SO2 and trace SeO2 from flue gas: effect of SO2 on selenium capture and kinetics study.

PubMed

Li, Yuzhong; Tong, Huiling; Zhuo, Yuqun; Wang, Shujuan; Xu, Xuchang

2006-12-15

Sulfur dioxide (SO2) and trace elements are all pollutants derived from coal combustion. This study relates to the simultaneous removal of SO2 and trace selenium dioxide (SeO2) from flue gas by calcium oxide (CaO) adsorption in the moderate temperature range, especially the effect of SO2 presence on selenium capture. Experiments performed on a thermogravimetric analyzer (TGA) can reach the following conclusions. When the CaO conversion is relatively low and the reaction rate is controlled by chemical kinetics, the SO2 presence does not affect the selenium capture. When the CaO conversion is very high and the reaction rate is controlled by product layer diffusion, the SO2 presence and the product layer diffusion resistance jointly reduce the selenium capture. On the basis of the kinetics study, a method to estimate the trace selenium removal efficiency using kinetic parameters and the sulfur removal efficiency is developed.

Antioxidant-Mediated Effects in a Gerbil Model of Iron Overload

PubMed Central

Otto-Duessel, Maya; Aguilar, Michelle; Moats, Rex; Wood, John C.

2010-01-01

Introduction Iron cardiomyopathy is a lethal complication of transfusion therapy in thalassemia major. Nutritional supplements decreasing cardiac iron uptake or toxicity would have clinical significance. Murine studies suggest taurine may prevent oxidative damage and inhibit Ca2+-channel-mediated iron transport. We hypothesized that taurine supplementation would decrease cardiac iron-overloaded toxicity by decreasing cardiac iron. Vitamin E and selenium served as antioxidant control. Methods Animals were divided into control, iron, taurine, and vitamin E/selenium groups. Following sacrifice, iron and selenium measurements, histology, and biochemical analyses were performed. Results No significant differences were found in heart and liver iron content between treatment groups, except for higher hepatic dry-weight iron concentrations in taurine-treated animals (p < 0.03). Serum iron increased with iron loading (751 ± 66 vs. 251 ± 54 μg/dl, p < 0.001) and with taurine (903 ± 136 μg/dl, p = 0.03). Conclusion Consistent with oxidative stress, iron overload increased cardiac malondialdehyde levels, decreased heart glutathione peroxidase (GPx) activity, and increased serum aspartate aminotransferase. Taurine ameliorated these changes, but only significantly for liver GPx activity. Selenium and vitamin E supplementation did not improve oxidative markers and worsened cardiac GPx activity. These results suggest that taurine acts primarily as an antioxidant rather than inhibiting iron uptake. Future studies should illuminate the complexity of these results. PMID:17940334

Toxicity and oxidative stress of different forms of organic selenium and dietary protein in mallard ducklings

USGS Publications Warehouse

Hoffman, D.J.; Heinz, G.H.; LeCaptain, L.J.; Eisemann, J.D.; Pendleton, G.W.

1996-01-01

Concentrations of over 100 ppm (mg/kg) selenium (Se) have been found in aquatic plants and insects associated with irrigation drainwater and toxicity to fish and wildlife. Composition of diet for wild ducklings may vary in selenium-contaminated environments. Earlier studies have compared toxicities and oxidative stress of Se as selenite to those of seleno-DL-methionine (DL) in mallards (Anas platyrhynchos). 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 except for 30 ppm Se as W. 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 at 30 ppm in the diet was the most toxic form, resulting in high mortality (64%) and impaired growth (>50%) in survivors and the greatest increase in ratio of oxidized to reduced hepatic glutathione (GSH). Se as both L and DL decreased the concentrations of hepatic GSH and total thiols. Se as Y accumulated the least in liver (approximately 50% of other forms) and had less effect on GSH and total thiols. In a second experiment, in which the basal diet was a commercial duck feed (22 % protein), survival was not affected by 30 ppm Se as DL, L, or Y and oxidative effects on GSH metabolism were less pronounced than with the wheat diet.

Effects of selenium on short-term control of hyperthyroidism due to Graves' disease treated with methimazole: results of a randomized clinical trial.

PubMed

Leo, M; Bartalena, L; Rotondo Dottore, G; Piantanida, E; Premoli, P; Ionni, I; Di Cera, M; Masiello, E; Sassi, L; Tanda, M L; Latrofa, F; Vitti, P; Marcocci, C; Marinò, M

2017-03-01

In spite of previous conflicting results, an adjuvant role of selenium in the treatment of Graves' disease (GD) hyperthyroidism has been proposed. To address this issue, a randomized clinical trial was carried out aimed at investigating whether selenium is beneficial on the short-term control of GD hyperthyroidism treated with methimazole (MMI). Thirty newly diagnosed hyperthyroid GD patients were randomly assigned to treatment with: (i) MMI or (ii) MMI plus selenium. Primary outcomes were: control of hyperthyroidism and clinical and biochemical manifestations of hyperthyroidism [heart rate, cholesterol, sex hormone-binding globulin (SHBG), hyperthyroidism symptoms] at 90 days. Baseline features of the two groups did not differ. Serum selenium at baseline was similar in the two groups and within the recommended range to define selenium sufficiency. Selenium increased with treatment in the MMI-selenium group and became significantly higher than in the MMI group. Serum malondialdehyde, a marker of oxidative stress, was similar in the two groups and decreased significantly with treatment, with no difference between groups. Administration of MMI was followed by a reduction of FT 3 and FT 4 , with no difference between groups. Heart rate, SHBG and symptoms of hyperthyroidism decreased, whereas total cholesterol increased in both groups with no difference between groups. Our study, carried out in a selenium-sufficient cohort of GD patients, failed to show an adjuvant role of selenium in the short-term control of hyperthyroidism. However, selenium might be beneficial in patients from selenium-deficient areas, as well as in the long-term outcome of antithyroid treatment.

Protective Effects of Combined Selenium and Punica granatum Treatment on Some Inflammatory and Oxidative Stress Markers in Arsenic-Induced Hepatotoxicity in Rats.

PubMed

Shafik, Noha M; El Batsh, Maha M

2016-01-01

Oxidative stress is one of the major mechanisms implicated in inorganic arsenic poisoning. Punica granatum is known by its free radical scavenging properties. The aim of this study was to evaluate the protective role of combined selenium and P. granatum against arsenic-induced liver injury. Seventy-five female albino rats were divided into five groups (of 15 rats each). Toxicity was induced by oral sodium arsenite (5.5 mg/kg body weight (bw) daily) (group ІІ). Treatment of arsenic-intoxicated rats was induced by daily oral administration of sodium selenite (3 mg/kg bw) (group ІІІ), 100 mg of P. granatum ethanol extract per kilogram body weight dissolved in 300 mL distilled water in three divided doses (100 mL of this suspension every 8 h) (group IV), and combined daily oral treatment with both selenite and P. granatum ethanol extract (group V). After 3 weeks, serum and liver tissues were obtained from the decapitated rats for different estimations. Hepatotoxicity was demonstrated by significant elevation in liver weights and activities of liver enzymes, alanine aminotransferase (ALT) and aspartate aminotransferase (AST), and decrease in serum total proteins and albumin (p < 0.05) which were confirmed by histopathological examination. Additionally, arsenic hepatotoxicity led to an increased values of malondialdehyde, advanced oxidation protein products, nitric oxide, and interleukin-6 (IL-6) (p < 0.05) and decreased activity of thioredoxin reductase, values of total anti-oxidant capacity, and nuclear factor erythroid 2-related factor 2 (Nrf2) gene expression. Significant improvement in all assessed parameters was observed in rat group treated with both P. granatum and selenium. It was concluded that combined P. granatum and selenium treatment had a synergistic hepatoprotective effect against arsenic toxicity through activation of Nrf2 anti-oxidant pathway.

Detailed study of selenium and other constituents in water, bottom sediment, soil, alfalfa, and biota associated with irrigation drainage in the Uncompahgre Project area and in the Grand Valley, west-central Colorado, 1991-93

USGS Publications Warehouse

Butler, D.L.; Wright, W.G.; Stewart, K.C.; Osmundson, B.C.; Krueger, R.P.; Crabtree, D.W.

1996-01-01

In 1985, the U.S. Department of the Interior began a program to study the effects of irrigation drainage in the Western United States. These studies were done to determine whether irrigation drainage was causing problems related to human health, water quality, and fish and wildlife resources. Results of a study in 1991-93 of irrigation drainage associated with the Uncompahgre Project area, located in the lower Gunnison River Basin, and of the Grand Valley, located along the Colorado River, are described in this report. The focus of the report is on the sources, distribution, movement, and fate of selenium in the hydrologic and biological systems and the effects on biota. Generally, other trace- constituent concentrations in water and biota were not elevated or were not at levels of concern. Soils in the Uncompahgre Project area that primarily were derived from Mancos Shale contained the highest concentrations of total and watrer-extractable selenium. Only 5 of 128\\x11alfalfa samples had selenium concentrations that exceeded a recommended dietary limit for livestock. Selenium data for soil and alfalfa indicate that irrigation might be mobilizing and redistributing selenium in the Uncompahgre Project area. Distribution of dissolved selenium in ground water is affected by the aqueous geochemical environment of the shallow ground- water system. Selenium concentrations were as high as 1,300\\x11micrograms per liter in water from shallow wells. The highest concentrations of dissolved selenium were in water from wells completed in alluvium overlying the Mancos Shale of Cretaceous age; selenium concentrations were lower in water from wells completed in Mancos Shale residuum. Selenium in the study area could be mobilized by oxidation of reduced selenium, desorption from aquifer sediments, ion exchange, and dissolution. Infiltration of irrigation water and, perhaps nitrate, provide oxidizing conditions for mobilization of selenium from alluvium and shale residuum and for transport to streams and irrigation drains that are tributary to the Gunnison, Uncompahgre, and Colorado Rivers. Selenium concentrations in about 64\\x11percent of water samples collected from the lower Gunnison River and about 50 percent of samples from the Colorado River near the Colorado-Utah State line exceeded the U.S.\\x11Environmental Protection Agency criterion of 5\\x11micrograms per liter for protection of aquatic life. Almost all selenium concentrations in samples collected during the nonirrigation season from Mancos Shale areas exceeded the aquatic-life criterion. The maximum selenium concentrations in surface-water samples were 600\\x11micrograms per liter in the Uncompahgre Project area and 380\\x11micrograms per liter in the Grand Valley. Irrigation drainage from the Uncompahgre Project and the Grand Valley might account for as much as 75 percent of the selenium load in the Colorado River near the Colorado-Utah State line. The primary source areas of selenium were the eastern side of the Uncompahgre Project and the western one-half of the Grand Valley, where there is extensive irrigation on soils derived from Mancos Shale. The largest mean selenium loads from tributary drainages were 14.0 pounds per day from Loutsenhizer Arroyo in the Uncompahgre Project and 12.8 pounds per day from Reed Wash in the Grand Valley. Positive correlations between selenium loads and dissolved-solids loads could indicate that salinity-control projects designed to decrease dissolved-solids loads also could decrease selenium loads from the irrigated areas. Selenium concentrations in irrigation drainage in the Grand Valley were much higher than concentrations predicted by simple evaporative concentration of irrigation source water. Selenium probably is removed from pond water by chemical and biological processes and incorporated into bottom sediment. The maximum selenium concentration in bottom sediment was 47 micrograms per gram from a pond on the eastern side of the

Adsorption of selenium by amorphous iron oxyhydroxide and manganese dioxide

USGS Publications Warehouse

Balistrieri, L.S.; Chao, T.T.

1990-01-01

This work compares and models the adsorption of selenium and other anions on a neutral to alkaline surface (amorphous iron oxyhydroxide) and an acidic surface (manganese dioxide). Selenium adsorption on these oxides is examined as a function of pH, particle concentration, oxidation state, and competing anion concentration in order to assess how these factors might influence the mobility of selenium in the environment. The data indicate that 1. 1) amorphous iron oxyhydroxide has a greater affinity for selenium than manganese dioxide, 2. 2) selenite [Se(IV)] adsorption increases with decreasing pH and increasing particle concentration and is stronger than selenate [Se(VI)] adsorption on both oxides, and 3. 3) selenate does not adsorb on manganese dioxide. The relative affinity of selenate and selenite for the oxides and the lack of adsorption of selenate on a strongly acidic surface suggests that selenate forms outer-sphere complexes while selenite forms inner-sphere complexes with the surfaces. The data also indicate that the competition sequence of other anions with respect to selenite adsorption at pH 7.0 is phosphate > silicate > molybdate > fluoride > sulfate on amorphous iron oxyhydroxide and molybdate ??? phosphate > silicate > fluoride > sulfate on manganese dioxide. The adsorption of phosphate, molybdate, and silicate on these oxides as a function of pH indicates that the competition sequences reflect the relative affinities of these anions for the surfaces. The Triple Layer surface complexation model is used to provide a quantitative description of these observations and to assess the importance of surface site heterogeneity on anion adsorption. The modeling results suggest that selenite forms binuclear, innersphere complexes with amorphous iron oxyhydroxide and monodentate, inner-sphere complexes with manganese dioxide and that selenate forms outer-sphere, monodentate complexes with amorphous iron oxyhydroxide. The heterogeneity of the oxide surface sites is reflected in decreasing equilibrium constants for selenite with increasing adsorption density and both experimental observations and modeling results suggest that manganese dioxide has fewer sites of higher energy for selenite adsorption than amorphous iron oxyhydroxide. Modeling and interpreting the adsorption of phosphate, molybdate, and silicate on the oxides are made difficult by the lack of constraint in choosing surface species and the fact that equally good fits can be obtained with different surface species. Finally, predictions of anion competition using the model results from single adsorbate systems are not very successful because the model does not account for surface site heterogeneity. Selenite adsorption data from a multi-adsorbate system could be fit if the equilibrium constant for selenite is decreased with increasing anion adsorption density. ?? 1990.

Comparing immune and anti-oxidant effects of selenium sources by in ovo treatment on post-hatch experimental avian necrotic enteritis

USDA-ARS?s Scientific Manuscript database

This study was conducted to investigate the effects of in ovo injection of selenium (Se) from 3 different sources on modulating the immune and antioxidant responses in broiler chickens in experimental necrotic enteritis (NE). SE contents of Sodium selenite (Na2SeO3 [SS]), Se-enriched yeast (YS), and...

Selenium Partitioning and Removal Across a Wet FGD Scrubber at a Coal-Fired Power Plant.

PubMed

Senior, Constance L; Tyree, Corey A; Meeks, Noah D; Acharya, Chethan; McCain, Joseph D; Cushing, Kenneth M

2015-12-15

Selenium has unique fate and transport through a coal-fired power plant because of high vapor pressures of oxide (SeO2) in flue gas. This study was done at full-scale on a 900 MW coal-fired power plant with electrostatic precipitator (ESP) and wet flue gas desulfurization (FGD) scrubber. The first objective was to quantify the partitioning of selenium between gas and condensed phases at the scrubber inlet and outlet. The second objective was to determine the effect of scrubber operation conditions (pH, mass transfer, SO2 removal) on Se removal in both particulate and vapor phases. During part of the testing, hydrated lime (calcium hydroxide) was injected upstream of the scrubber. Gas-phase selenium and particulate-bound selenium were measured as a function of particle size at the inlet and outlet of the scrubber. The total (both phases) removal of Se across the scrubber averaged 61%, and was enhanced when hydrated lime sorbent was injected. There was evidence of gas-to-particle conversion of selenium across the scrubber, based on the dependence of selenium concentration on particle diameter downstream of the scrubber and on thermodynamic calculations.

Selenium preserves keratinocyte stemness and delays senescence by maintaining epidermal adhesion

PubMed Central

Jobeili, Lara; Rousselle, Patricia; Béal, David; Blouin, Eric; Roussel, Anne-Marie; Damour, Odile; Rachidi, Walid

2017-01-01

Skin is constantly exposed to environmental factors such as pollutants, chemicals and ultra violet radiation (UV), which can induce premature skin aging and increase the risk of skin cancer. One strategy to reduce the effect of oxidative stress produced by environmental exposure is the application of antioxidant molecules. Among the endogenous antioxidants, selenoproteins play a key role in antioxidant defense and in maintaining a reduced cellular environment. Selenium, essential for the activity of selenoproteins, is a trace element that is not synthesized by organisms and must be supplied by diet or supplementation. The aim of this study is to evaluate the effect of Selenium supplementation on skin aging, especially on keratinocytes, the main cells of the epidermis. Our results demonstrate for the first time to our knowledge, the major role of Selenium on the replicative life span of keratinocytes and on aging skin. Selenium protects keratinocyte stem cells (KSCs) against senescence via preservation of their stemness phenotype through adhesion to the basement membrane. Additionally, Selenium supplementation maintains the homeostasis of skin during chronological aging in our senescent skin equivalent model. Controlled supplementation with Selenium could be a new strategy to protect skin against aging. PMID:29176034

A gene-environment interaction analysis of plasma selenium with prevalent and incident diabetes: The Hortega study.

PubMed

Galan-Chilet, Inmaculada; Grau-Perez, Maria; De Marco, Griselda; Guallar, Eliseo; Martin-Escudero, Juan Carlos; Dominguez-Lucas, Alejandro; Gonzalez-Manzano, Isabel; Lopez-Izquierdo, Raul; Briongos-Figuero, Laisa Socorro; Redon, Josep; Chaves, Felipe Javier; Tellez-Plaza, Maria

2017-08-01

Selenium and single-nucleotide-polymorphisms in selenoprotein genes have been associated to diabetes. However, the interaction of selenium with genetic variation in diabetes and oxidative stress-related genes has not been evaluated as a potential determinant of diabetes risk. We evaluated the cross-sectional and prospective associations of plasma selenium concentrations with type 2 diabetes, and the interaction of selenium concentrations with genetic variation in candidate polymorphisms, in a representative sample of 1452 men and women aged 18-85 years from Spain. The geometric mean of plasma selenium levels in the study sample was 84.2µg/L. 120 participants had diabetes at baseline. Among diabetes-free participants who were not lost during the follow-up (N=1234), 75 developed diabetes over time. The multivariable adjusted odds ratios (95% confidence interval) for diabetes prevalence comparing the second and third to the first tertiles of plasma selenium levels were 1.80 (1.03, 3.14) and 1.97 (1.14, 3.41), respectively. The corresponding hazard ratios (95% CI) for diabetes incidence were 1.76 (0.96, 3.22) and 1.80 (0.98, 3.31), respectively. In addition, we observed significant interactions between selenium and polymorphisms in PPARGC1A, and in genes encoding mitochondrial proteins, such as BCS1L and SDHA, and suggestive interactions of selenium with other genes related to selenoproteins and redox metabolism. Plasma selenium was positively associated with prevalent and incident diabetes. While the statistical interactions of selenium with polymorphisms involved in regulation of redox and insulin signaling pathways provide biological plausibility to the positive associations of selenium with diabetes, further research is needed to elucidate the causal pathways underlying these associations. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

Role of Selenium from Different Sources in Prevention of Pulmonary Arterial Hypertension Syndrome in Broiler Chickens.

PubMed

Zamani Moghaddam, A K; Mehraei Hamzekolaei, M H; Khajali, F; Hassanpour, H

2017-11-01

Pulmonary arterial hypertension (PAH) syndrome in broilers is associated with hypoxia, which prevails at high altitude. Oxidative stress is the pathogenic mechanism underlying PAH. Because selenium is key element in the structure of antioxidant enzymes, we evaluated pulmonary hypertensive responses in broiler chickens fed with diets supplemented with organic or nano-selenium. One hundred forty-four broilers (starting at 5 days old) were fed with (i) control group: birds received a standard diet; (ii) nano-selenium group: birds were fed with basal diet supplemented with nano-selenium at 0.3 mg/kg; and (iii) organic selenium group: birds received basal diet supplemented with organic selenium at 0.3 mg/kg. We assessed growth performance, carcass characteristics, antioxidant variables, blood parameters, and small intestine morphology. Although Se supplementation did not affect growth performance, carcass traits, and organ weight (P > 0.05), the right to total ventricular weight ratio (RV:TV), malondialdehyde concentration in the liver, and heterophil to lymphocyte ratio were significantly lower in the nano-selenium group relative to the control (P < 0.05). Chickens that received nano-selenium also elicited significantly higher antibody titers after 24 h of an injection of sheep red blood cells (P < 0.05). Nano-selenium supplementation also significantly increased villus height, absorptive surface area, and lamina propria thickness relative to the control (P < 0.05) in different segments of the small intestine. In contrast, organic selenium supplement improved intestinal morphometry only in the jejunum. We conclude that dietary supplementation of 0.30 mg/kg nano-selenium could prevent right ventricular hypertrophy as reflected by reduced RV:TV, reduced levels of lipid peroxidation in the liver, and improved gut function.

The prospective protective effect of selenium nanoparticles against chromium-induced oxidative and cellular damage in rat thyroid

PubMed Central

Hassanin, Kamel MA; El-Kawi, Samraa H Abd; Hashem, Khalid S

2013-01-01

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. This was shown by the significant decrease in free T3 and T4 and GSH levels, which was accompanied by significant increases in catalase, SOD, and MDA in the chromium-treated group compared to the control group. Se nanoparticles have a protective effect on K2Cr2O7-induced thyroid damage, as a result of correcting the free T3 and T4 levels and GSH, catalase, SOD, and MDA compared to the K2Cr2O7-treated group. Administration of nano-selenium alone in the nano-selenium-treated group had no toxic effect on rats’ thyroid compared to the control group. The biochemical results were confirmed by histopathological, immunohistochemical and pathomorphological studies. PMID:23658489

Protective effects of riboflavin and selenium on brain microsomal Ca2+-ATPase and oxidative damage caused by glyceryl trinitrate in a rat headache model.

PubMed

Nazıroğlu, Mustafa; Çelik, Ömer; Uğuz, Abdulhadi Cihangir; Bütün, Ayşe

2015-03-01

Migraine headaches are considered to be associated with increased mitochondrial energy metabolism. Mitochondrial oxidative stress is also important in migraine headache pathophysiology although riboflavin and selenium (Se) induced a modulator role on mitochondrial oxidative stress in the brain. The current study aimed to determine the effects of Se with/without riboflavin on the microsomal membrane Ca(2+)-ATPase (MMCA), lipid peroxidation, antioxidant, and electroencephalography (EEG) values in glyceryl trinitrate (GTN)-induced brain injury rats. Thirty-two rats were randomly divided into four groups. The first group was used as the control, and the second group was the GTN group. Se and Se plus oral riboflavin were administered to rats constituting the third and fourth groups for 10 days prior to GTN administration. The second, third, and fourth groups received GTN to induce headache. Ten hours after the administration of GTN, the EEG records and brain cortex samples were obtained for all groups. Brain cortex microsomes were obtained from the brain samples. The brain and microsomal lipid peroxidation levels were higher in the GTN group compared to the control group, whereas they were decreased by selenium and selenium + riboflavin treatments. Vitamin A, vitamin C, vitamin E, and reduced glutathione (GSH) concentrations of the brain and MMCA, GSH and glutathione peroxidase values of microsomes were decreased by the GTN administration, although the values and β-carotene concentrations were increased by Se and Se + riboflavin treatments. There was no significant change in EEG records of the four groups. In conclusion, Se with/without riboflavin administration protected against GTN-induced brain oxidative toxicity by inhibiting free radicals and the modulation of MMCA activity and supporting the antioxidant redox system.

Deficient selenium status of a healthy adult Spanish population.

PubMed

Millán Adame, E; Florea, D; Sáez Pérez, L; Molina López, J; López-González, B; Pérez de la Cruz, A; Planells del Pozo, E

2012-01-01

Selenium is an essential micronutrient for human health, being a cofactor for enzymes with antioxidant activity that protect the organism from oxidative damage. An inadequate intake of this mineral has been associated with the onset and progression of chronic diseases such as hypertension, diabetes, coronary diseases, asthma, and cancer. For this reason, knowledge of the plasma and erythrocyte selenium levels of a population makes a relevant contribution to assessment of its nutritional status. The objective of the present study was to determine the nutritional status of selenium and risk of selenium deficiency in a healthy adult population in Spain by examining food and nutrient intake and analyzing biochemical parameters related to selenium metabolism, including plasma and erythrocyte levels and selenium-dependent glutathione peroxidase (GPx) enzymatic activity. We studied 84 healthy adults (31 males and 53 females) from the province of Granada, determining their plasma and erythrocyte selenium concentrations and the association of these levels with the enzymatic activity of glutathione peroxidase (GPx) and with life style factors. We also gathered data on their food and nutrient intake and the results of biochemical analyses. Correlations were studied among all of these variables. The mean plasma selenium concentration was 76.6 ± 17.3 μg/L (87.3 ± 17.4 μg/L in males, 67.3 ± 10.7 μg/L in females), whereas the mean erythrocyte selenium concentration was 104.6 μg/L (107.9 ± 26.1 μg/L in males and 101.7 ± 21.7 μg/L in females). The nutritional status of selenium was defined by the plasma concentration required to reach maximum GPx activity, establishing 90 μg/L as reference value. According to this criterion, 50% of the men and 53% of the women were selenium deficient. Selenium is subjected to multiple regulation mechanisms. Erythrocyte selenium is a good marker of longer term selenium status, while plasma selenium appears to be a marker of short-term nutritional status. The present findings indicate a positive correlation between plasma selenium concentration and the practice of physical activity. Bioavailability studies are required to establish appropriate reference levels of this mineral for the Spanish population.

Selenium suppresses glutamate-induced cell death and prevents mitochondrial morphological dynamic alterations in hippocampal HT22 neuronal cells.

PubMed

Ma, Yan-Mei; Ibeanu, Gordon; Wang, Li-Yao; Zhang, Jian-Zhong; Chang, Yue; Dong, Jian-Da; Li, P Andy; Jing, Li

2017-01-19

Previous studies have indicated that selenium supplementation may be beneficial in neuroprotection against glutamate-induced cell damage, in which mitochondrial dysfunction is considered a major pathogenic feature. However, the exact mechanisms by which selenium protects against glutamate-provoked mitochondrial perturbation remain ambiguous. In this study glutamate exposed murine hippocampal neuronal HT22 cell was used as a model to investigate the underlying mechanisms of selenium-dependent protection against mitochondria damage. We find that glutamate-induced cytotoxicity was associated with enhancement of superoxide production, activation of caspase-9 and -3, increases of mitochondrial fission marker and mitochondrial morphological changes. Selenium significantly resolved the glutamate-induced mitochondria structural damage, alleviated oxidative stress, decreased Apaf-1, caspases-9 and -3 contents, and altered the autophagy process as observed by a decline in the ratio of the autophagy markers LC3-I and LC3-II. These findings suggest that the protection of selenium against glutamate stimulated cell damage of HT22 cells is associated with amelioration of mitochondrial dynamic imbalance.

[Pharmaconutrition with parenteral selenium in sepsis].

PubMed

Langlois, P L; de Oliveira Figliolino, L F; Hardy, G; Manzanares, W

2014-04-01

Critical illness is characterized by oxidative stress which leads to multiple organ failure, and sepsis-related organ dysfunction remains the most common cause of death in the intensive care unit. Over the last 2 decades, different antioxidant therapies have been developed to improve outcomes in septic patients. According to recent evidence, selenium therapy should be considered the cornerstone of the antioxidant strategies. Selenium given as selenious acid or sodium selenite should be considered as a drug or pharmaconutrient with prooxidant and cytotoxic effects when a loading dose in intravenous bolus form is administered, particularly in the early stage of severe sepsis/septic shock. To date, several phase ii trials have demonstrated that selenium therapy may be able to decrease mortality, improve organ dysfunction and reduce infections in critically ill septic patients. The effect of selenium therapy in sepsis syndrome must be confirmed by large, well designed phase iii clinical trials. The purpose of this review is to discuss current evidence on selenium pharmaconutrition in sepsis syndrome. Copyright © 2013 Elsevier España, S.L. and SEMICYUC. All rights reserved.

Deep-Sea Water Containing Selenium Provides Intestinal Protection against Duodenal Ulcers through the Upregulation of Bcl-2 and Thioredoxin Reductase 1

PubMed Central

Yang, Chih-Ching; Yao, Chien-An; Lin, Yi-Ruu; Yang, Jyh-Chin; Chien, Chiang-Ting

2014-01-01

Deep-sea water (DSW), which is rich in micronutrients and minerals and with antioxidant and anti-inflammatory qualities, may be developed as marine drugs to provide intestinal protection against duodenal ulcers. We determined several characteristics in the modified DSW. We explored duodenal pressure, oxygenation, microvascular blood flow, and changes in pH and oxidative redox potential (ORP) values within the stomach and duodenum in response to tap water (TW, hardness: 2.48 ppm), DSW600 (hardness: 600 ppm), and DSW1200 (hardness: 1200 ppm) in Wistar rats and analyzed oxidative stress and apoptosis gene expressions by cDNA and RNA microarrays in the duodenal epithelium. We compared the effects of drinking DSW, MgCl2, and selenium water on duodenal ulcers using pathologic scoring, immunohistochemical analysis, and Western blotting. Our results showed DSW has a higher pH value, lower ORP value, higher scavenging H2O2 and HOCl activity, higher Mg2+ concentrations, and micronutrients selenium compared with TW samples. Water infusion significantly increased intestinal pressure, O2 levels, and microvascular blood flow in DSW and TW groups. Microarray showed DSW600, DSW1200, selenium water upregulated antioxidant and anti-apoptotic genes and downregulated pro-apoptotic gene expression compared with the TW group. Drinking DSW600, DSW1200, and selenium water but not Mg2+ water significantly enhanced Bcl-2 and thioredoxin reductase 1 expression. Bax/Bcl-2/caspase 3/poly-(ADP-ribose)-polymerase signaling was activated during the pathogenesis of duodenal ulceration. DSW drinking reduced ulcer area as well as apoptotic signaling in acetic acid-induced duodenal ulcers. DSW, which contains selenium, provides intestinal protection against duodenal ulcers through the upregulation of Bcl-2 and thioredoxin reductase 1. PMID:24984066

Monosodium glutamate induced testicular toxicity and the possible ameliorative role of vitamin E or selenium in male rats.

PubMed

Hamza, Reham Z; Al-Harbi, Mohammad S

2014-01-01

Monosodium glutamate (MSG) has been recognized as flavor enhancer that adversely affects male reproductive systems. The present study was carried out to evaluate the potential protective role of vitamin E (vit E) or selenium against MSG induced oxidative stress and histopathological changes in testis tissues of rats. Mature male Wistar rats weighing 150-200 g BW were allocated to evenly twelve groups each group of ten animals, the first group was maintained as control group, the 2nd, 3rd and 4th groups were administered MSG in three different dose levels (low, medium and high) (6, 17.5 and 60 mg/kg BW), the 5th and 6th groups were given vit E in two doses (low and high) (150 and 200 mg/kg), the 7th and 8th groups were administered selenium in two doses (low and high) (0.25 and 1 mg/kg) daily via gavage for a period of 30 days. Meanwhile the 9th and 10th groups were given combinations of MSG (high dose) and vit E while, the 11th and 12th groups were given MSG (high dose) plus selenium in two recommended doses for each one. Monosodium glutamate caused an elevation in lipid peroxidation level parallel with significant decline in SOD, CAT as well as GPx activities in testis tissues. Administration of vit E or selenium to MSG-treated groups declined lipid peroxidation, increased SOD, CAT, GPx activities. Selenium or vit E significantly reduced MSG induced histopathological changes by the entire restoration of the histological structures and the testicular antioxidant status to great extent in treated rats. In conclusion, supplementation of selenium or vit E could ameliorate the MSG induced testicular toxicity to great extent and reduce the oxidative stress on testis tissues.

Elemental selenium particles at nano-size (Nano-Se) are more toxic to Medaka (Oryzias latipes) as a consequence of hyper-accumulation of selenium: a comparison with sodium selenite.

PubMed

Li, Hongcheng; Zhang, Jinsong; Wang, Thanh; Luo, Wenru; Zhou, Qunfang; Jiang, Guibin

2008-09-29

Recent studies have shown that elemental selenium particles at nano-size (Nano-Se) exhibited comparable bioavailability and less toxicity in mice and rats when compared to sodium selenite, selenomethinine and methylselenocysteine. However, little is known about the toxicity profile of Nano-Se in aquatic animals. In the present study, toxicities of Nano-Se and selenite in selenium-sufficient Medaka fish were compared. Selenium bioaccumulation and subsequent clearance in fish livers, gills, muscles and whole bodies were examined after 10 days of exposure to Nano-Se and selenite (100 microg Se/L) and again after 7 days of depuration. Both forms of selenium exposure effectively increased selenium concentrations in the investigated tissues. Surprisingly, Nano-Se was found to be more hyper-accumulated in the liver compared to selenite with differences as high as sixfold. Selenium clearance of both Nano-Se and selenite occurred at similar ratios in whole bodies and muscles but was not rapidly cleared from livers and gills. Nano-Se exhibited strong toxicity for Medaka with an approximately fivefold difference in terms of LC(50) compared to selenite. Nano-Se also caused larger effects on oxidative stress, most likely due to more hyper-accumulation of selenium in liver. The present study suggests that toxicity of nanoparticles can largely vary between different species and concludes that the evaluation of nanotoxicology should be carried out on a case-by-case basis.

Long-term organic selenium supplementation overcomes the trade-off between immune and antioxidant systems in pacu (Piaractus mesopotamicus).

PubMed

Takahashi, Leonardo Susumu; Biller-Takahashi, Jaqueline Dalbello; Mansano, Cleber Fernando Menegasso; Urbinati, Elisabeth Criscuolo; Gimbo, Rodrigo Yukihiro; Saita, Marcos Vinícius

2017-01-01

Selenium (Se) is an essential nutrient for antioxidant defenses in fish because of its role in preventing immunosuppression caused by oxidative stress. In this study it was demonstrated the relation between the oxidative stress and immune status after a long Se supplementation period, as a result of the evaluation of immunological, hematological and antioxidant responses, as well as growth performance of pacu fed diets supplemented with different concentrations of organic selenium (0, 0.3, 0.6, 0.9, and 1.8 mg Se-yeast/kg, but the final analyzed selenium concentrations were 0.72, 0.94, 1.15, 1.57 and 2.51 mg/kg, respectively) for 65 days. Dietary Se supplementation at 1.15 mg Se-yeast/kg (analyzed value) restored the production of antioxidant enzymes (glutathione peroxidase (GPx) and glutathione S-transferase (GST)), and consequently allowed the increased of some immunological parameters (leukocyte respiratory burst activity and lysozyme activity), hematological parameters (red blood cell count (RBC), hematocrit (HTC), mean corpuscular volume (MCV), and white blood cell count (WBC)). Se supplementation in pacu diets at 1.15 mg Se-yeast/kg for 65 days improved immune response and antioxidant defenses, suggesting that oxidative stress impairs immune system response to prevent excessive reactive oxygen species in cells and indicating the occurrence of a physiological trade-off between immune and antioxidant systems. Higher Se levels, such as 1.57 mg Se-yeast/kg increased the leukocyte respiratory burst activity, the WBC and thrombocyte counts, the RBC and HTC, and the GST and GPx enzymes. However, 2.51 mg Se-yeast/kg decreased the lysozyme levels, the WBC and thrombocyte counts, the RBC, HTC and MCV, and the GST and GPx enzymes. Those findings are important to future studies because showed the negative effect of oxidative stress on immunity, and may help to prevent any inhibition of the expected immune response after immunomodulators administration and vaccination. Also it was possible to meet the dietary selenium requirement of pacu, that was estimated to be 1.56 mg/kg. Copyright © 2016 Elsevier Ltd. All rights reserved.

Protective effects of Nano-elemental selenium against chromium-vi-induced oxidative stress in broiler liver.

PubMed

Xueting, L; Rehman, M U; Zhang, H; Tian, X; Wu, X; Shixue; Mehmood, K; Zhou, D

2018-01-01

The valuable role of selenium in mitigation of oxidative stress and heavy metal toxicity is well-known. Thus, the aim of the current study on broiler chickens was to examine whether nano elemental selenium (Nano-Se) supplementation can reduce the effects of chromium VI (K2Cr2O7) toxicity. For this purpose, a total of 150, one-day-old broiler chickens were allotted to five groups with three replicates: control group (standard diet), poisoned group (K2Cr2O7 via drinking water), protection group (K2Cr2O7 + Nano- Se), cure group (K2Cr2O7 for initial 2 weeks and then Nano-Se), and prevention group (opposite to the cure group). The broilers were detected by the activities of marker enzymes and oxidative stress markers including, aspartate aminotransferase (AST), alanine transaminase (ALT), gamma-glutamyl transferase (GGT) and superoxide dismutase (SOD), glutathione peroxidase (GSH-px), malondialdehyde (MDA), respectively. The (K2Cr2O7 administration caused histopathological damage in the liver of the chickens. Moreover, changes in serum biochemical indicators and oxidative stress parameters were also observed. Nano-Se supplementation increased the levels of GSH-px but reduced the activities of SOD, MDA, GGT, ALT and AST in the experimental groups (P less than 0.05). Our results showed that Nano-Se plays a protective role by preventing the oxidative stress induced by the chromium VI in broiler chickens.

Biological effects of a nano red elemental selenium.

PubMed

Zhang, J S; Gao, X Y; Zhang, L D; Bao, Y P

2001-01-01

A novel selenium form, nano red elemental selenium (Nano-Se) was prepared by adding bovine serum albumin to the redox system of selenite and glutathione. Nano-Se has a 7-fold lower acute toxicity than sodium selenite in mice (LD(50) 113 and 15 mg Se/kg body weight respectively). In Se-deficient rat, both Nano-Se and selenite can increase tissue selenium and GPx activity. The biological activities of Nano-Se and selenite were compared in terms of cell proliferation, enzyme induction and protection against free racial-mediated damage in human hepatoma HepG2 cells. Nano-Se and selenite are similarly cell growth inhibited and stimulated synthesis of glutathione peroxidase (GPx), phospholipid hydroperoxide glutathione peroxidase (PHGPx) and thioredoxin reductase (TR). When HepG2 cells were co-treated with selenium and glutathione, Nano-Se showed less pro-oxidative effects than selenite, as measured by cell growth. These results demonstrate that Nano-Se has a similar bioavailability in the rat and antioxidant effects on cells.

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

PubMed

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 detrimental effects of concomitant moderate methylmercury exposure.

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

PubMed

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.

Ameliorative effects of selenium on arsenic-induced cytotoxicity in PC12 cells via modulating autophagy/apoptosis.

PubMed

Rahman, Md Mostafizur; Uson-Lopez, Rachael A; Sikder, Md Tajuddin; Tan, Gongxun; Hosokawa, Toshiyuki; Saito, Takeshi; Kurasaki, Masaaki

2018-04-01

Arsenic is well known toxicant responsible for human diseases including cancers. On the other hand, selenium is an essential trace element with significant chemopreventive effects, anticancer potentials and antioxidant properties. Although previous studies have reported antagonism/synergism between arsenic and selenium in biological systems, the biomolecular mechanism/s is still inconclusive. Therefore, to elucidate the molecular phenomena in cellular level, we hypothesized that co-exposure of selenium with arsenic may have suppressive effects on arsenic-induced cytotoxicity. We found that selenium in co-exposure with arsenic increases cell viability, and suppresses oxidative stress induced by arsenic in PC12 cells. Consequently, DNA fragmentation due to arsenic exposure was also reduced by arsenic and selenium co-exposure. Furthermore, western blot analyses revealed that simultaneous exposure of both metals significantly inhibited autophagy which further suppressed apoptosis through positively regulation of key proteins; p-mTOR, p-Akt, p-Foxo1A, p62, and expression of ubiquitin, Bax, Bcl2, NFкB, and caspases 3 and 9, although those are negatively regulated by arsenic. In addition, reverse transcriptase PCR analysis confirmed the involvement of caspase cascade in cell death process induced by arsenic and subsequent inhibition by co-exposure of selenium with arsenic. The cellular accumulation study of arsenic in presence/absence of selenium via inductively coupled plasma mass spectrometry confirmed that selenium effectively retarded the uptake of arsenic in PC12 cells. Finally, these findings imply that selenium is capable to modulate arsenic-induced intrinsic apoptosis pathway via enhancement of mTOR/Akt autophagy signaling pathway through employing antioxidant potentials and through inhibiting the cellular accumulation of arsenic in PC12 cells. Copyright © 2017 Elsevier Ltd. All rights reserved.

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

PubMed

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.

Use of Elemental Sulfur or Selenium in a Novel One-Pot Copper-Catalyzed Tandem Cyclization of Functionalized Ynamides Leading to Benzosultams.

PubMed

Siva Reddy, Alla; Kumara Swamy, K C

2015-06-19

A novel and efficient [Cu]-catalyzed one-pot regio- and stereospecific synthesis of benzo[1,4,2]dithiazine 1,1-dioxides and benzo[1,4,2]thiaselenazine 1,1-dioxides by cyclization of functionalized ynamides with elemental sulfur/selenium has been developed. Its generality is elegantly illustrated by extension to benzodithiazepines and benzothiaselenazepines. Involvement of water in the reaction is demonstrated by the incorporation of (2)D at the olefinic site by using D2O in place of water. Selective oxidation at sulfur in benzo[1,4,2]dithiazine 1,1-dioxide by using mCPBA as the oxidizing agent is also described.

Combined selenium and vitamin C deficiency causes cell death in guinea pig skeletal muscle.

PubMed

Hill, Kristina E; Motley, Amy K; May, James M; Burk, Raymond F

2009-03-01

Combined antioxidant deficiencies of selenium and vitamin E or vitamin E and vitamin C in guinea pigs result in clinical illness. We hypothesized that combined selenium and vitamin C deficiency would have clinical consequences because in vitro interactions of these antioxidant nutrients have been reported. Because guinea pigs are dependent on dietary vitamin C, weanling male guinea pigs were fed selenium-deficient or control diet for 15 weeks before imposing vitamin C deficiency. Four dietary groups were formed and studied 3 weeks later: controls, vitamin C deficient, selenium deficient, and doubly deficient. Deficiencies were confirmed by determinations of glutathione peroxidase activity and vitamin C concentration in liver and skeletal muscle. Plasma creatine phosphokinase activity and liver, kidney, heart, and quadriceps histopathology were determined. Doubly deficient animals had moderately severe skeletal muscle cell death as judged by histopathology and plasma creatine phosphokinase activity of 6630 +/- 4400 IU/L (control, 70 + or - 5; vitamin C deficient, 95 + or - 110; selenium deficient, 280 + or - 250). Liver, kidney, and heart histology was normal in all groups. Muscle alpha-tocopherol levels were not depressed in the doubly deficient group, but muscle F2 isoprostane concentrations were elevated in them and correlated with markers of cell death. We conclude that combining selenium and vitamin C deficiencies in the guinea pig causes cell death in skeletal muscle that is more severe than the injury caused by selenium deficiency. The elevation of muscle F2 isoprostanes is compatible with the cell death being caused by oxidative stress.

Selenium speciation in phosphate mine soils and evaluation of a sequential extraction procedure using XAFS.

PubMed

Favorito, Jessica E; Luxton, Todd P; Eick, Matthew J; Grossl, Paul R

2017-10-01

Selenium is a trace element found in western US soils, where ingestion of Se-accumulating plants has resulted in livestock fatalities. Therefore, a reliable understanding of Se speciation and bioavailability is critical for effective mitigation. Sequential extraction procedures (SEP) are often employed to examine Se phases and speciation in contaminated soils but may be limited by experimental conditions. We examined the validity of a SEP using X-ray absorption spectroscopy (XAS) for both whole and a sequence of extracted soils. The sequence included removal of soluble, PO 4 -extractable, carbonate, amorphous Fe-oxide, crystalline Fe-oxide, organic, and residual Se forms. For whole soils, XANES analyses indicated Se(0) and Se(-II) predominated, with lower amounts of Se(IV) present, related to carbonates and Fe-oxides. Oxidized Se species were more elevated and residual/elemental Se was lower than previous SEP results from ICP-AES suggested. For soils from the SEP sequence, XANES results indicated only partial recovery of carbonate, Fe-oxide and organic Se. This suggests Se was incompletely removed during designated extractions, possibly due to lack of mineral solubilization or reagent specificity. Selenium fractions associated with Fe-oxides were reduced in amount or removed after using hydroxylamine HCl for most soils examined. XANES results indicate partial dissolution of solid-phases may occur during extraction processes. This study demonstrates why precautions should be taken to improve the validity of SEPs. Mineralogical and chemical characterizations should be completed prior to SEP implementation to identify extractable phases or mineral components that may influence extraction effectiveness. Sequential extraction procedures can be appropriately tailored for reliable quantification of speciation in contaminated soils. Copyright © 2017 Elsevier Ltd. All rights reserved.

Adsorption mechanisms of selenium oxyanions at the aluminum oxide/water interface

DOE Office of Scientific and Technical Information (OSTI.GOV)

Peak, Derek

2008-06-09

Sorption processes at the mineral/water interface typically control the mobility and bioaccessibility of many inorganic contaminants such as oxyanions. Selenium is an important micronutrient for human and animal health, but at elevated concentrations selenium toxicity is a concern. The objective of this study was to determine the bonding mechanisms of selenate (SeO{sub 4}{sup 2-}) and selenite (SeO{sub 3}{sup 2-}) on hydrous aluminum oxide (HAO) over a wide range of reaction pH using extended X-ray absorption fine structure (EXAFS) spectroscopy. Additionally, selenate adsorption on corundum ({alpha}-Al{sub 2}O{sub 3}) was studied to determine if adsorption mechanisms change as the aluminum oxide surfacemore » structure changes. The overall findings were that selenite forms a mixture of outer-sphere and inner-sphere bidentate-binuclear (corner-sharing) surface complexes on HAO, selenate forms primarily outer-sphere surface complexes on HAO, and on corundum selenate forms outer-sphere surface complexes at pH 3.5 but inner-sphere monodentate surface complexes at pH 4.5 and above. It is possible that the lack of inner-sphere complex formation at pH 3.5 is caused by changes in the corundum surface at low pH or secondary precipitate formation. The results are consistent with a structure-based reactivity for metal oxides, wherein hydrous metal oxides form outer-sphere complexes with sulfate and selenate, but inner-sphere monodentate surface complexes are formed between sulfate and selenate and {alpha}-Me{sub 2}O{sub 3}.« less

Toenail selenium, genetic variation in selenoenzymes and risk and outcome in glioma.

PubMed

Peeri, Noah C; Creed, Jordan H; Anic, Gabriella M; Thompson, Reid C; Olson, Jeffrey J; LaRocca, Renato V; Chowdhary, Sajeel A; Brockman, John D; Gerke, Travis A; Nabors, L Burton; Egan, Kathleen M

2018-05-16

Selenium is an essential trace element obtained through diet that plays a critical role in DNA synthesis and protection from oxidative damage. Selenium intake and polymorphisms in selenoproteins have been linked to the risk of certain cancers though data for glioma are sparse. In a case-control study of glioma, we examined the associations of selenium in toenails and genetic variants in the selenoenzyme pathway with the risk of glioma and patient survival. A total of 423 genetic variants in 29 candidate genes in the selenoenzyme pathway were studied in 1547 glioma cases and 1014 healthy controls. Genetic associations were also examined in the UK Biobank cohort comprised of 313,868 persons with 322 incident glioma cases. Toenail selenium was measured in a subcohort of 300 glioma cases and 300 age-matched controls from the case-control study. None of the 423 variants studied were consistently associated with glioma risk in the case-control and cohort studies. Moreover, toenail selenium in the case-control study had no significant association with glioma risk (p trend = 0.70) or patient survival among 254 patients with high grade tumors (p trend = 0.70). The present study offers no support for the hypothesis that selenium plays a role in the onset of glioma or patient outcome. Copyright © 2018 Elsevier Ltd. All rights reserved.

Acute selenium selenite exposure effects on oxidative stress biomarkers and essential metals and trace-elements in the model organism zebrafish (Danio rerio).

PubMed

Hauser-Davis, R A; Silva, J A N; Rocha, Rafael C C; Saint'Pierre, Tatiana; Ziolli, R L; Arruda, M A Z

2016-01-01

Selenium (Se) is an essential trace-element that becomes toxic when present at high concentrations. Little is known regarding Se effects on parameters such as oxidative stress biomarkers. The aim of the present study was to investigate the effects of acute selenium exposure on oxidative stress biomarkers in a model organism, zebrafish (Danio rerio). Fish were exposed to selenium selenite at 1mgL(-1). Reduced glutathione (GSH), and metallothionein (MT) concentrations were determined in liver, kidney and brain, with MT also being determined in bile. Essential metals and trace-elements were also determined by inductively coupled mass spectrometry (ICP-MS) in order to verify possible metal homeostasis alterations. GSH concentrations in liver, kidney and brain increased significantly (1.05±0.03μmolg(-1) ww, 1.42±0.03μmolg(-1) ww and 1.64±0.03μmolg(-1) ww, respectively) in the Se-exposed group when compared to the controls (0.88±0.05μmolg(-1) ww, 0.80±0.04μmolg(-1) ww and 0.89±0.03μmolg(-1) ww for liver, kidney and brain, respectively). MT levels in Se-exposed liver (0.52±0.03μmolg(-1) ww) decreased significantly in comparison to the control group (0.64±0.02μmolg(-1) ww), while levels in bile increased, albeit non-significantly. This is in accordance with previous studies that indicate efficient biliary MT action, leading to a rapid metabolism and elimination of contaminants from the body. Levels in the brain increased significantly after Se-exposure (0.57±0.01μmolg(-1) ww) when compared to the control group (0.35±0.03μmolg(-1) ww) since this organ does not present a detoxification route as quick as the liver-gallbladder route. Several metal and trace-elements were altered with Se-exposure, indicating that excess of selenium results in metal dyshomeostasis. This is the first report on metal dyshomeostasis due to Se-exposure, which may be the first step in the mechanism of action of selenium toxicity, as is postulated to occur in certain major human pathophysiologies. Copyright © 2015 Elsevier GmbH. All rights reserved.

Selenite modulates the level of phenolics and nutrient element to alleviate the toxicity of arsenite in rice (Oryza sativa L.).

PubMed

Chauhan, Reshu; Awasthi, Surabhi; Tripathi, Preeti; Mishra, Seema; Dwivedi, Sanjay; Niranjan, Abhishek; Mallick, Shekhar; Tripathi, Pratibha; Pande, Veena; Tripathi, Rudra Deo

2017-04-01

Arsenic (As) contamination of paddy rice is a serious threat all over the world particularly in South East Asia. Selenium (Se) plays important role in protection of plants against various abiotic stresses including heavy metals. Moreover, arsenite (AsIII) and selenite (SeIV) can be biologically antagonistic due to similar electronic configuration and sharing the common transporter for their uptake in plant. In the present study, the response of oxidative stress, phenolic compounds and nutrient elements was analyzed to investigate Se mediated As tolerance in rice seedlings during AsIII and SeIV exposure in hydroponics. Selenite (25µM) significantly decreased As accumulation in plant than As (25µM) alone treated plants. Level of oxidative stress related parameters viz., reactive oxygen species (ROS), lipid peroxidation, electrical conductivity, nitric oxide and pro-oxidant enzyme (NADPH oxidase), were in the order of As>As+Se>control>Se. Selenium ameliorated As phytotoxicity by increased level of phenolic compounds particularly gallic acid, protocatechuic acid, ferulic acid and rutin and thiol metabolism related enzymes viz., serine acetyl transferase (SAT) and cysteine synthase (CS). Selenium supplementation enhanced the uptake of nutrient elements viz., Fe, Mn, Co, Cu, Zn, Mo, and improved plant growth. The results concluded that Se addition in As contaminated environment might be an important strategy to reduce As uptake and associated phytotoxicity in rice plant by modulation of phenolic compounds and increased uptake of nutrient elements. Copyright © 2016 Elsevier Inc. All rights reserved.

Selenium- and tellurium-containing multifunctional redox agents as biochemical redox modulators with selective cytotoxicity.

PubMed

Jamier, Vincent; Ba, Lalla A; Jacob, Claus

2010-09-24

Various human diseases, including different types of cancer, are associated with a disturbed intracellular redox balance and oxidative stress (OS). The past decade has witnessed the emergence of redox-modulating compounds able to utilize such pre-existing disturbances in the redox state of sick cells for therapeutic advantage. Selenium- and tellurium-based agents turn the oxidizing redox environment present in certain cancer cells into a lethal cocktail of reactive species that push these cells over a critical redox threshold and ultimately kill them through apoptosis. This kind of toxicity is highly selective: normal, healthy cells remain largely unaffected, since changes to their naturally low levels of oxidizing species produce little effect. To further improve selectivity, multifunctional sensor/effector agents are now required that recognize the biochemical signature of OS in target cells. The synthesis of such compounds provides interesting challenges for chemistry in the future.

Serum Concentration of Zinc, Copper, Selenium, Manganese, and Cu/Zn Ratio in Children and Adolescents with Myopia.

PubMed

Fedor, Monika; Socha, Katarzyna; Urban, Beata; Soroczyńska, Jolanta; Matyskiela, Monika; Borawska, Maria H; Bakunowicz-Łazarczyk, Alina

2017-03-01

The purpose of the present study was the assessment of the serum concentration of antioxidant microelements-zinc, copper, selenium, manganese, and Cu/Zn ratio in children and adolescents with myopia. Eighty-three children were examined (mean age 14.36 ± 2.49 years) with myopia. The control group was 38 persons (mean age 12.89 ± 3.84 years). Each patient had complete eye examination. The serum concentration of zinc, copper, manganese, and selenium was determined by atomic absorption spectrometry. Cu/Zn ratio, which is the indicator of the oxidative stress, was also calculated. The average serum concentration of zinc in myopic patients was significantly lower (0.865 ± 0.221 mg L -1 ) in comparison to the control group (1.054 ± 0.174 mg L -1 ). There was significantly higher Cu/Zn ratio in myopic patients (1.196 ± 0.452) in comparison to that in the control group (0.992 ± 0.203). The average serum concentration of selenium in the study group was significantly lower (40.23 ± 12.07 μg L -1 ) compared with that in the control group (46.00 ± 12.25 μg L -1 ). There were no essential differences between serum concentration of copper and manganese in the study group and the control group. Low serum concentration of zinc and selenium in myopic children may imply an association between insufficiency of these antioxidant microelements and the development of the myopia and could be the indication for zinc and selenium supplementation in the prevention of myopia. Significantly, higher Cu/Zn ratio in the study group can suggest the relationship between myopia and oxidative stress.

Effects of nano-selenium on performance, meat quality, immune function, oxidation resistance, and tissue selenium content in broilers.

PubMed

Cai, S J; Wu, C X; Gong, L M; Song, T; Wu, H; Zhang, L Y

2012-10-01

This study was conducted to investigate the effect of nano-selenium (nano-Se) on performance, meat quality, immune function, oxidation resistance, and tissue selenium content in broilers. A total of five hundred forty 1-d-old male Arbor Acres broilers were randomly allotted to 1 of 5 treatments with each treatment being applied to 6 replicates of 18 chicks. The 5 treatments consisted of corn-soybean meal-based diets supplemented with 0.0, 0.3, 0.5, 1.0, or 2.0 mg/kg of nano-Se. The selenium content of the unsupplemented control diet was 0.09 mg/kg for the starter phase (0 to 21 d) and 0.08 mg/kg for the grower phase (22 to 42 d). There were no significant differences (P > 0.05) in performance, meat color, or immune organ index (thymus, bursa, and spleen) due to supplementation with nano-Se. On d 42, a significant quadratic effect of nano-Se was observed on glutathione peroxidase activity, free radical inhibition, contents of IgM, glutathione, and malondialdehyde in serum, on glutathione peroxidase activity, free radical inhibition in liver, and on glutathione peroxidase activity in muscle, with birds fed 0.30 mg/kg of nano-Se exhibiting the best effect and birds fed 2.0 mg/kg of nano-Se showing the worst effect on these parameters. Liver and muscle selenium content increased linearly and quadratically as the dietary nano-Se level increased (P < 0.01), and reached the highest value when 2.0 mg/kg of nano-Se was fed. Based on a consideration of all experiment indexes, 0.3 to 0.5 mg/kg is suggested to be the optimum level of supplementation of nano-Se, and the maximum supplementation of nano-Se could not be more than 1.0 mg/kg in broilers.

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

PubMed

Stefanello, Sílvio Terra; Gubert, Priscila; Puntel, Bruna; Mizdal, Caren Rigon; de Campos, Marli Matiko Anraku; Salman, Syed M; Dornelles, Luciano; Avila, Daiana Silva; Aschner, Michael; Soares, Félix Alexandre Antunes

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 -tolylselanyl)propan-2-amine (C1) and 1-(2-methoxyphenylselanyl)-3-phenylpropan-2-amine (C2) and analogs of DPDS (1,2-bis (2-methoxyphenyl) diselenide (C3) and 1,2-bis p -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 Caenorhabditis 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 Caenorhabditis 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.

Microbial oxidation of elemental selenium in soil slurries and bacterial cultures

USGS Publications Warehouse

Dowdle, P.R.; Oremland, R.S.

1998-01-01

The microbial oxidation of elemental selenium [Se(O)] was studied by employing 75Se(O) as a tracer. Live, oxic soil slurries demonstrated a linear production of mostly Se(IV), with the formation of smaller quantities of Se(VI). Production of both Se(IV) and Se(VI) was inhibited by autoclaving, formalin, antibiotics, azide, and 2,4-dinitrophenol, thereby indicating the involvement of microbes. Oxidation of Se(O) in slurries was enhanced by addition of acetate, glucose, or sulfide, which implied involvement of chemoheterotrophs as well as chemoautotrophic thiobacilli. Cultures of Thiobacillus ASN-1, Leptothrix MnB1, and a heterotrophic soil enrichment all oxidized Se(O) with Se(VI) observed as the major product rather than Se(IV). This indicated that microbial oxidation in soils is partly constrained by the adsorption of Se(IV) onto soil surfaces. Rate constants for unamended soil slurry Se(O) oxidation ranged from 0.0009 to 0.0117 day-1 which were 3-4 orders of magnitude lower than those reported for dissimilatory Se(VI) reduction in organic-rich, anoxic sediments.The microbial oxidation of elemental selenium [Se(0)] was studied by employing 75Se(0) as a tracer. Live, oxic soil slurries demonstrated a linear production of mostly Se(IV), with the formation of smaller quantities of Se(VI). Production of both Se(IV) and Se(VI) was inhibited by autoclaving, formalin, antibiotics, azide, and 2,4-dinitrophenol, thereby indicating the involvement of microbes. Oxidation of Se(O) in slurries was enhanced by addition of acetate, glucose, or sulfide, which implied involvement of chemoheterotrophs as well as chemoautotrophic thiobacilli. Cultures of Thiobacillus ASN-1, Leptothrix MnB1, and a heterotrophic soil enrichment all oxidized Se(O) with Se(VI) observed as the major product rather than Se(IV). This indicated that microbial oxidation in soils is partly constrained by the adsorption of Se(IV) onto soil surfaces. Rate constants for unamended soil slurry Se(O) oxidation ranged from 0.0009 to 0.0117 day-1 which were 3-4 orders of magnitude lower than those reported for dissimilatory Se(VI) reduction in organic-rich, anoxic sediments.

Chemical form of selenium differentially influences DNA repair pathways following exposure to lead nitrate.

PubMed

McKelvey, Shauna M; Horgan, Karina A; Murphy, Richard A

2015-01-01

Lead, an environmental toxin is known to induce a broad range of physiological and biochemical dysfunctions in humans through a number of mechanisms including the deactivation of antioxidants thus leading to generation of reactive oxygen species (ROS) and subsequent DNA damage. Selenium on the other hand has been proven to play an important role in the protection of cells from free radical damage and oxidative stress, though its effects are thought to be form and dose dependent. As the liver is the primary organ required for metabolite detoxification, HepG2 cells were chosen to assess the protective effects of various selenium compounds following exposure to the genotoxic agent lead nitrate. Initially DNA damage was quantified using a comet assay, gene expression patterns associated with DNA damage and signalling were also examined using PCR arrays and the biological pathways which were most significantly affected by selenium were identified. Interestingly, the organic type selenium compounds (selenium yeast and selenomethionine) conferred protection against lead induced DNA damage in HepG2 cells; this is evident by reduction in the quantity of DNA present in the comet tail of cells cultured in their presence with lead. This trend also followed through the gene expression changes noted in DNA damage pathways analysed. These results were in contrast with those of inorganic sodium selenite which promoted lead induced DNA damage evident in both the comet assay results and the gene expression analysis. Over all this study provided valuable insights into the effects which various selenium compounds had on the DNA damage and signalling pathway indicating the potential for using organic forms of selenium such as selenium enriched yeast to protect against DNA damaging agents. Copyright © 2014 Elsevier GmbH. All rights reserved.

Selenium-mediated protection in reversing the sensitivity of bacterium to the bactericidal antibiotics.

PubMed

Li, Zhonglei; Tan, Jun; Shao, Lei; Dong, Xiaojing; Ye, Richard D; Chen, Daijie

2017-05-01

Inducing production of damaging reactive oxygen species (ROS) is an important criterion to distinguish the bactericidal antibiotics from bacteriostatic antibiotics. Selenoenzymes were generally recognized to be a powerful antioxidant capable of scavenging free radicals, protecting the cells from the harmful effects of ROS. Therefore, the present study was carried out to investigate the selenium (Se)-mediated protection in reversing antibiotic sensitivity and the role of selenoenzymes in alleviating the negative effects of oxidative stress. The cellular antioxidant activity of Se-enriched bacteria was analyzed, as well as intracellular ROS production and elimination when Se-enriched bacteria in the presence of various antibiotics. Compared to complete inhibition of the parental strain by bactericidal antibiotics, it only exhibited slight and reversible inhibition of Se-enriched Escherichia coli ATCC25922 and Staphylococcus aureus ATCC25923 at the same conditions, which indicated that intracellular selenium provided substantial protection against antibiotics. ROS generation caused by bactericidal antibiotics was confirmed by fluorescence spectrophotometry using 2', 7'-dichloro- uorescein diacetate (DCFH-DA) as substrate. The time course experiments of pretreatment with selenium showed significant decrease of ROS level at 2h. In summary, the present study provides experimental evidence supporting selenoenzymes has good scavenging effect to ROS and can protect bacteria from oxidative stress injury induced by bactericidal antibiotics. Copyright © 2017 Elsevier GmbH. All rights reserved.

Biocompatibility selenium nanoparticles with an intrinsic oxidase-like activity

NASA Astrophysics Data System (ADS)

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.

Biogenesis of Selenium Nanoparticles Using Green Chemistry.

PubMed

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.

Use of selenium-silymarin mix reduces lower urinary tract symptoms and prostate specific antigen in men.

PubMed

Vostalova, Jitka; Vidlar, Ales; Ulrichova, Jitka; Vrbkova, Jana; Simanek, Vilim; Student, Vladimir

2013-12-15

The aim of this double-blind, placebo controlled clinical trial was to assess the effects of a combination of selenium and silymarin in men with lower urinary tract symptoms, benign prostatic hyperplasia and a prostate specific antigen (PSA) ≤2.5ng/ml. The volunteers were randomized to two groups: the first one (n=26) received 240μg selenium (in the form of yeast l-selenomethionine) plus 570mg silymarin daily for 6 months and the second (n=29) received placebo. Outcome measures were changes in the International Prostate Symptom Score (IPSS), bladder volume (V), urinary flow rate, ultrasound estimated postvoid residual urine volume (RV), serum PSA, testosterone and selenium levels, safety clinical biochemistry, hematology and oxidative stress parameters at baseline and on day 180. The results showed statistically significant differences (p<0.05) between treatment and control groups for the following parameters: IPSS score, urodynamic parameters: maximal rate of urine flow (Qmax), average flow (Qave), V and RV, total PSA value and serum selenium levels. There was a significant reduction in PSA in the selenium-silymarin group but no effect on blood testosterone level. Overall the treatment was well-tolerated with no adverse effects. Copyright © 2013 Elsevier GmbH. All rights reserved.

Competition between the Brain and Testes under Selenium-Compromised Conditions: Insight into Sex Differences in Selenium Metabolism and Risk of Neurodevelopmental Disease.

PubMed

Pitts, Matthew W; Kremer, Penny M; Hashimoto, Ann C; Torres, Daniel J; Byrns, China N; Williams, Christopher S; Berry, Marla J

2015-11-18

Selenium (Se) is essential for both brain development and male fertility. Male mice lacking two key genes involved in Se metabolism (Scly(-/-)Sepp1(-/-) mice), selenoprotein P (Sepp1) and Sec lyase (Scly), develop severe neurological dysfunction, neurodegeneration, and audiogenic seizures that manifest beginning in early adulthood. We demonstrate that prepubescent castration of Scly(-/-)Sepp1(-/-) mice prevents behavioral deficits, attenuates neurodegeneration, rescues maturation of GABAergic inhibition, and increases brain selenoprotein levels. Moreover, castration also yields similar neuroprotective benefits to Sepp1(-/-) and wild-type mice challenged with Se-deficient diets. Our data show that, under Se-compromised conditions, the brain and testes compete for Se utilization, with concomitant effects on neurodevelopment and neurodegeneration. Selenium is an essential trace element that promotes male fertility and brain function. Herein, we report that prepubescent castration provides neuroprotection by increasing selenium-dependent antioxidant activity in the brain, revealing a competition between the brain and testes for selenium utilization. These findings provide novel insight into the interaction of sex and oxidative stress upon the developing brain and have potentially significant implications for the prevention of neurodevelopmental disorders characterized by aberrant excitatory/inhibitory balance, such as schizophrenia and epilepsy. Copyright © 2015 the authors 0270-6474/15/3515326-13$15.00/0.

Oxidative desulfurization of dibenzothiophene with hydrogen peroxide catalyzed by selenium(IV)-containing peroxotungstate.

PubMed

Hu, Yiwen; He, Qihui; Zhang, Zheng; Ding, Naidong; Hu, Baixing

2011-11-28

With stoichiometric H(2)O(2) as oxidant, dibenzothiophene (DBT) is oxidized to its corresponding sulfone with high efficiency, catalyzed by a sub-valence heteronuclear peroxotungstate, [C(18)H(37)N(CH(3))(3)](4)[H(2)Se(IV)(3)W(6)O(34)], under mild biphase conditions and the catalyst shows remarkable selectivity of catalytic oxidation towards DBT, cinnamyl alcohol and quinoline.

Nephroprotective and antioxidant significance of selenium and α-tocopherol on lead acetate-induced toxicity of Nile Tilapia (Oreochromis niloticus).

PubMed

Hashish, Emad A; Elgaml, Shimaa A; El-Murr, Abdelhakeem; Khalil, Ryad

2015-06-01

The kidney plays an important physiological function, maintaining the osmoregulation and electrolyte balance of Nile tilapia (Oreochromis niloticus). Selenium and α-tocopherol (α-toc) are potent antioxidants, which improve the aquaculture health. In this study, we tested the potential ability of selenium and α-toc to alleviate the oxidative stress in the kidney induced by lead toxicity. Two hundred and twenty-five O. niloticus were divided into five groups. The control group received a basal diet. Lead nephrotoxicity was induced by daily application of 73.40 mg lead acetate/liter water for up to 10 weeks. Selenium and α-tocopherol were given 1 week before lead intoxication. Selenium was administered as sodium selenite, 4 mg/kg dry diet. Alpha-tocopherol acetate was administered as α-toc, 200 mg/kg dry diet. The last group received a mixture of selenium and α-toc in diet. Fish treated with selenium and/or α-toc (groups III-V) showed an amelioration of the adverse effects of lead toxicity and significant improvement in serum electrolytes (calcium, inorganic phosphate, and magnesium) and creatinine level compared with the positive control group (P ≤ 0.05). Treated groups showed significant decrease in superoxide dismutase (SOD) and reduced glutathione (GSH) activity with significant increase in malondialdehyde (MDA; P ≤ 0.05). It could be concluded that selenium and α-toc have a potential antioxidant effect and have the ability to improve the kidney function after lead intoxication of O. niloticus.

Adiposity and Serum Selenium in U.S. Adults.

PubMed

Zhong, Qiuan; Lin, Ruoxi; Nong, Qingjiao

2018-06-05

Requirements for selenium and other antioxidant nutrients are increased in pro-oxidant and pro-inflammatory conditions such as excess adiposity. Data concerning the association of excess general and central adiposity with circulating selenium concentrations, however, are limited. We examined the cross-sectional associations of body mass index (BMI), percent body fat (%BF), and waist circumference (WC) with serum selenium concentrations in 6440 men and 6849 women aged ≥20 years who participated in the U.S. Third National Health and Nutrition Examination Survey. In multivariable analyses, the average difference (95% confidence interval (CI)) in serum selenium comparing the highest with the lowest quartiles of BMI was -4.0 (-5.5, -1.6) ng/mL in both men and women. These inverse associations were evident after further adjustment for WC. For %BF, the average differences (95% CI) in serum selenium between the highest and the lowest quartiles of %BF were -1.7 (-4.2, 0.7) ng/mL in men and -4.5 (-7.0, -1.9) ng/mL in women. The inverse association in women persisted after adjusting for WC. For WC, the average differences (95% CI) in serum selenium between the highest and the lowest quartiles were -1.9 (-3.8, -0.1) ng/mL in men and -3.9 (-5.8, -2.0) ng/mL in women. After further adjustment for BMI, the inverse association became positive in men and null in women. Our findings suggest that general and central adiposity have different associations with serum selenium levels and that these associations may depend on gender.

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

PubMed

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.

Impact of vitamin E and selenium on antioxidant capacity and lipid oxidation of cheddar cheese in accelerated ripening.

PubMed

Batool, Maryam; Nadeem, Muhammad; Imran, Muhammad; Gulzar, Nabila; Shahid, Muhammad Qamar; Shahbaz, Muhammad; Ajmal, Muhammad; Khan, Imran Taj

2018-04-11

Ripening of cheddar cheese is a time taking process, duration of the ripening may be as long as one year. Long ripening time is a big hindrance in the popularity of cheese in developing countries. Further, energy resources in these countries are either insufficient or very expensive. Therefore, those methods of cheese ripening should be discovered which can significantly reduce the ripening time without compromising the quality characteristics of cheddar cheese. In accelerated ripening, cheese is usually ripened at higher temperature than traditional ripening temperatures. Ripening of cheddar cheese at high temperature with the addition of vitamin E and selenium is not previously studied. This investigation aimed to study the antioxidant activity of selenium and vitamin E in accelerated ripening using cheddar cheese as an oxidation substrate. The ripening of cheddar cheese was performed at 18 °C and to prevent lipid oxidation, vitamin E and selenium were used alone and in combination. The treatments were as: cheddar cheese without any addition of vitamin E and selenium (T1), cheddar cheese added with 100 mg/kg vitamin E (T 2 ), 200 mg/kg vitamin E (T 3 ), 800 μg/kg selenium (T 4 ), 1200 μg/kg selenium (T 5 ), vitamin E 100 mg/kg + 800 μg/kg selenium (T 6 ) and vitamin E 200 mg/kg + 1200 μg/kg selenium (T 7 ). Traditional cheddar cheese ripne ripened at 4-6 °C for 9 months was used as positive control. Cheese samples were ripened at 18 °C for a period of 12 weeks and analyzed for chemical and oxidative stability characteristics at 0, 6 and 12 weeks of storage. All these treatments were compared with a cheddar cheese without vitamin E, selenium and ripened at 4 °C or 12 weeks. Vacuum packaged cheddar cheese was ripened 18 °C for a period of 12 weeks and analyzed for chemical and oxidative stability characteristics at 0, 4 and 8 weeks of storage period. Addition of Vitamin E and selenium did not have any effect on moisture, fat and protein content of cheddar cheese. After 6 weeks of ripening, total antioxidant capacity of T 1 , T 2 , T 3 , T 4 , T 5 , T 6 , T 7 and standard cheese were 29.61%, 44.7%, 53.6%, 42.5%, 41.4%, 64.1%, 85.1% and 25.4%. After 6 weeks of ripening, reducing power of T 1 , T 2 , T 3 , T 4 , T 5 , T 6 , T 7 and SC cheese were 14.7%, 18.1%, 26.3%, 19.2%, 25.3%, 33.4%, 40.3% and 11.6%. After 6 weeks of ripening, 1, 1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging activity of T 6 and T 7 were 54.2% and 66.9%. While, DPPH free radical scavenging activity of T 1 and standard cheese after 6 weeks of ripening were, 19.1 and 18.5%, respectively. Free fatty acids of vitamin E and selenium supplemented, non-supplemented and standard cheese were not significantly influenced from each other in 0, 6 and 12 weeks old cheddar cheese. Peroxide values of T 1 , T 2 , T 3 , T 4 , T 5 , T 6 , T 7 and standard cheese after 6 weeks of accelerated ripening were 1.19, 1.05, 0.88, 1.25, 0.29, 0.25, 0.24 and 0.28 (MeqO 2 /kg). After 6 weeks of ripening, anisidine value of T 6 and T 7 were 6.55 and 6.14. Conjugated dienes of T 1 , T 2 , T 3 , T 4 , T 5 , T 6 , T 7 and standard cheese, after 6 weeks of accelerated ripening were 0.61, 0.55, 0.42, 0.77, 0.65, 0.17, 0.15 and 0.19. After 6 weeks of accelerated ripening, concentrations unsaturated fatty acids in T 1 , T 2 , T 3 , T 4 , T 5 , T 6 , T 7 and standard cheese decreased by18.19%, 17.45%, 16.82%, 16.19%, 12.71%, 8.48%, 6.92% and 14.71%. After 12 weeks of accelerated ripening, concentration of unsaturated fatty acids in T 1 , T 2 , T 3 , T 4 , T 5 , T 6 and T 7 and standard cheese decreased by 26.2%, 21.2%, 18.7%, 14.2%, 10.4%, 4.84%, 1.03% and 6.78%. Cheddar cheese samples added with vitamin E, selenium and their combinations produced more organic acids during the ripening period of 12 weeks. After 6 and 12 weeks of ripening, flavor score of T 6 and T 7 was better than standard ripened cheddar cheese. After 6 weeks of accelerated ripening, sensory characteristics of T 6 and T 7 were similar to cheddar cheese that was ripened at 4 °C for 9 months. Ripening time of cheddar cheese may be reduced to 6 weeks by elevated temperature (18 °C) using vitamin E and selenium as antioxidants at T 6 and T 7 levels.

Geologic sources and concentrations of selenium in the West-Central Denver Basin, including the Toll Gate Creek watershed, Aurora, Colorado, 2003-2007

USGS Publications Warehouse

Paschke, Suzanne S.; Walton-Day, Katherine; Beck, Jennifer A.; Webbers, Ank; Dupree, Jean A.

2014-01-01

Toll Gate Creek, in the west-central part of the Denver Basin, is a perennial stream in which concentrations of dissolved selenium have consistently exceeded the Colorado aquatic-life standard of 4.6 micrograms per liter. Recent studies of selenium in Toll Gate Creek identified the Denver lignite zone of the non-marine Cretaceous to Tertiary-aged (Paleocene) Denver Formation underlying the watershed as the geologic source of dissolved selenium to shallow ground-water and surface water. Previous work led to this study by the U.S. Geological Survey, in cooperation with the City of Aurora Utilities Department, which investigated geologic sources of selenium and selenium concentrations in the watershed. This report documents the occurrence of selenium-bearing rocks and groundwater within the Cretaceous- to Tertiary-aged Denver Formation in the west-central part of the Denver Basin, including the Toll Gate Creek watershed. The report presents background information on geochemical processes controlling selenium concentrations in the aquatic environment and possible geologic sources of selenium; the hydrogeologic setting of the watershed; selenium results from groundwater-sampling programs; and chemical analyses of solids samples as evidence that weathering of the Denver Formation is a geologic source of selenium to groundwater and surface water in the west-central part of the Denver Basin, including Toll Gate Creek. Analyses of water samples collected from 61 water-table wells in 2003 and from 19 water-table wells in 2007 indicate dissolved selenium concentrations in groundwater in the west-central Denver Basin frequently exceeded the Colorado aquatic-life standard and in some locations exceeded the primary drinking-water standard of 50 micrograms per liter. The greatest selenium concentrations were associated with oxidized groundwater samples from wells completed in bedrock materials. Selenium analysis of geologic core samples indicates that total selenium concentrations were greatest in samples containing indications of reducing conditions and organic matter (dark gray to black claystones and lignite horizons). The Toll Gate Creek watershed is situated in a unique hydrogeologic setting in the west-central part of the Denver Basin such that weathering of Cretaceous- to Tertiary-aged, non-marine, selenium-bearing rocks releases selenium to groundwater and surface water under present-day semi-arid environmental conditions. The Denver Formation contains several known and suspected geologic sources of selenium including: (1) lignite deposits; (2) tonstein partings; (3) organic-rich bentonite claystones; (4) salts formed as secondary weathering products; and possibly (5) the Cretaceous-Tertiary boundary. Organically complexed selenium and/or selenium-bearing pyrite in the enclosing claystones are likely the primary mineral sources of selenium in the Denver Formation, and correlations between concentration of dissolved selenium and dissolved organic carbon in groundwater indicate weathering and dissolution of organically complexed selenium from organic-rich claystone is a primary process mobilizing selenium. Secondary salts accumulated along fractures and bedding planes in the weathered zone are another potential geologic source of selenium, although their composition was not specifically addressed by the solids analyses. Results from this and previous work indicate that shallow groundwater and streams similarly positioned over Denver Formation claystone units at other locations in the Denver Basin also may contain concentrations of dissolved selenium greater than the Colorado aquatic-life standard or the drinking- water standard.

Neutralization by Metal Ions of the Toxicity of Sodium Selenide

PubMed Central

Dauplais, Marc; Lazard, Myriam; Blanquet, Sylvain; Plateau, Pierre

2013-01-01

Inert metal-selenide colloids are found in animals. They are believed to afford cross-protection against the toxicities of both metals and selenocompounds. Here, the toxicities of metal salt and sodium selenide mixtures were systematically studied using the death rate of Saccharomyces cerevisiae cells as an indicator. In parallel, the abilities of these mixtures to produce colloids were assessed. Studied metal cations could be classified in three groups: (i) metal ions that protect cells against selenium toxicity and form insoluble colloids with selenide (Ag+, Cd2+, Cu2+, Hg2+, Pb2+ and Zn2+), (ii) metal ions which protect cells by producing insoluble metal-selenide complexes and by catalyzing hydrogen selenide oxidation in the presence of dioxygen (Co2+ and Ni2+) and, finally, (iii) metal ions which do not afford protection and do not interact (Ca2+, Mg2+, Mn2+) or weakly interact (Fe2+) with selenide under the assayed conditions. When occurring, the insoluble complexes formed from divalent metal ions and selenide contained equimolar amounts of metal and selenium atoms. With the monovalent silver ion, the complex contained two silver atoms per selenium atom. Next, because selenides are compounds prone to oxidation, the stabilities of the above colloids were evaluated under oxidizing conditions. 5,5'-dithiobis-(2-nitrobenzoic acid) (DTNB), the reduction of which can be optically followed, was used to promote selenide oxidation. Complexes with cadmium, copper, lead, mercury or silver resisted dissolution by DTNB treatment over several hours. With nickel and cobalt, partial oxidation by DTNB occurred. On the other hand, when starting from ZnSe or FeSe complexes, full decompositions were obtained within a few tens of minutes. The above properties possibly explain why ZnSe and FeSe nanoparticles were not detected in animals exposed to selenocompounds. PMID:23342137

An in vitro examination of selenium-cadmium antagonism using primary cultures of rainbow trout (Oncorhynchus mykiss) hepatocytes.

PubMed

Jamwal, Ankur; Naderi, Mohammad; Niyogi, Som

2016-02-01

The present study evaluated the ameliorative properties of selenium (Se) against cadmium (Cd)-induced oxidative stress, using isolated rainbow trout (Oncorhynchus mykiss) hepatocytes in primary culture as the model experimental system. Cadmium (Cd) is known to induce cytotoxic effects by disrupting cellular oxidative homeostasis. On the other hand, selenium (Se) is an essential component of biological antioxidative machinery, and thus may provide protection against the toxic insults of Cd by augmenting the cellular antioxidant response. However, Se, when present above the threshold concentration, can also induce reactive oxygen species (ROS) generation and cause oxidative damage. In this experiment, trout hepatocytes in primary culture were exposed to 100 µM Cd, alone or in combination with different concentrations (25-500 µM) of selenite (SeO3(2-)) or selenomethionine (SeMet) for 48 h. Our findings indicated that both chemical forms of Se, at the lowest concentration used (25 µM), significantly reduced Cd-induced cytotoxicity (measured as cell viability). In contrast, Se at higher concentrations (≥ 50 µM) did not offer any protection against a Cd induced decrease in cell viability. The reduced cytotoxicity of Cd in the presence of 25 µM selenite or SeMet was associated with reduced intracellular ROS production, recovery of the cellular thiol status (ratio of reduced and oxidized glutathione), and amelioration in the activities of major enzymatic antioxidants (superoxide dismutase, catalase, and glutathione peroxidase). Co-treatment of hepatocytes with Cd and pharmacological antioxidants (TEMPO and NAC) also reduced Cd-induced oxidative stress in trout hepatocytes. This provided further evidence that Se likely ameliorates Cd toxicity via different antioxidative mechanisms.

Regulation of Selenoproteins and Methionine Sulfoxide Reductases A and B1 by Age, Calorie Restriction, and Dietary Selenium in Mice

PubMed Central

Novoselov, Sergey V.; Kim, Hwa-Young; Hua, Deame; Lee, Byung Cheon; Astle, Clinton M.; Harrison, David E.; Friguet, Bertrand; Moustafa, Mohamed E.; Carlson, Bradley A.; Hatfield, Dolph L.

2010-01-01

Abstract Methionine residues are susceptible to oxidation, but this damage may be reversed by methionine sulfoxide reductases MsrA and MsrB. Mammals contain one MsrA and three MsrBs, including a selenoprotein MsrB1. Here, we show that MsrB1 is the major methionine sulfoxide reductase in liver of mice and it is among the proteins that are most easily regulated by dietary selenium. MsrB1, but not MsrA activities, were reduced with age, and the selenium regulation of MsrB1 was preserved in the aging liver, suggesting that MsrB1 could account for the impaired methionine sulfoxide reduction in aging animals. We also examined regulation of Msr and selenoprotein expression by a combination of dietary selenium and calorie restriction and found that, under calorie restriction conditions, selenium regulation was preserved. In addition, mice overexpressing a mutant form of selenocysteine tRNA reduced MsrB1 activity to the level observed in selenium deficiency, whereas MsrA activity was elevated in these animals. Finally, we show that selenium regulation in inbred mouse strains is preserved in an outbred aging model. Taken together, these findings better define dietary regulation of methionine sulfoxide reduction and selenoprotein expression in mice with regard to age, calorie restriction, dietary Se, and a combination of these factors. Antioxid. Redox Signal. 12, 829–838. PMID:19769460

Effect of L-arginine and selenium added to a hypocaloric diet enriched with legumes on cardiovascular disease risk factors in women with central obesity: a randomized, double-blind, placebo-controlled trial.

PubMed

Alizadeh, Mohammad; Safaeiyan, Abdolrasoul; Ostadrahimi, Alireza; Estakhri, Rassul; Daneghian, Sevana; Ghaffari, Aida; Gargari, Bahram Pourghassem

2012-01-01

We aimed to discover if L-arginine and selenium alone or together can increase the effect of a hypocaloric diet enriched in legumes (HDEL) on central obesity and cardiovascular risk factors in women with central obesity. This randomized, double-blind, placebo-controlled trial was undertaken in 84 premenopausal women with central obesity. After a 2-week run-in period on an isocaloric diet, participants were randomly assigned to a control diet (HDEL), L-arginine (5 g/day) and HDEL, selenium (200 μg/day) and HDEL or L-arginine, selenium and HDEL for 6 weeks. Cardiovascular risk factors were assessed before intervention and 3 and 6 weeks afterwards. After 6 weeks, L-arginine had significantly reduced waist circumference (WC); selenium had significantly lowered fasting concentrations of serum insulin and the homeostasis model assessment of insulin resistance index; the interaction between L-arginine and selenium significantly reduced the fasting concentration of nitric oxides (NO(x)), and HDEL lowered triglycerides (TG) and WC and significantly increased the fasting concentration of NO(x). HDEL reduced high-sensitivity C-reactive protein levels in the first half of the study and returned them to basal levels in the second half. These data indicate the beneficial effects of L-arginine on central obesity, selenium on insulin resistance and HDEL on serum concentrations of NO(x) and TG. Copyright © 2012 S. Karger AG, Basel.

Modulation of Diabetes-Induced Oxidative Stress, Apoptosis, and Ca2+ Entry Through TRPM2 and TRPV1 Channels in Dorsal Root Ganglion and Hippocampus of Diabetic Rats by Melatonin and Selenium.

PubMed

Kahya, Mehmet Cemal; Nazıroğlu, Mustafa; Övey, İshak Suat

2017-04-01

Neuropathic pain and hippocampal injury can arise from the overload of diabetes-induced calcium ion (Ca 2+ ) entry and oxidative stress. The transient receptor potential (TRP) melastatin 2 (TRPM2) and TRP vanilloid type 1 (TRPV1) are expressed in sensory neurons and hippocampus. Moreover, activations of TRPM2 and TRPV1 during oxidative stress have been linked to neuronal death. Melatonin (MEL) and selenium (Se) have been considered potent antioxidants that detoxify a variety of reactive oxygen species (ROS) in neurological diseases. In order to better characterize the actions of MEL and Se in diabetes-induced peripheral pain and hippocampal injury through modulation of TRPM2 and TRPV1, we tested the effects of MEL and Se on apoptosis and oxidative stress in the hippocampal and dorsal root ganglion (DRG) neurons of streptozotocin (STZ)-induced diabetic rats. Fifty-eight rats were divided into six groups. The first group was used as control. The second group was used as the diabetic group. The third and fourth groups received Se and MEL, respectively. Intraperitoneal Se and MEL were given to diabetic rats in the fifth and sixth groups. On the 14th day, hippocampal and DRG neuron samples were freshly taken from all animals. The neurons were stimulated with a TRPV1 channel agonist (capsaicin) and a TRPM2 channel agonist (cumene hydroperoxide). We observed a modulator role of MEL and Se on intracellular free Ca 2+ concentrations, current densities of TRPM2 and TRPV1 channels, apoptosis, caspase 3, caspase 9, mitochondrial depolarization, reduced glutathione, glutathione peroxidase, lipid peroxidation, and intracellular ROS production values in the neurons. In addition, procaspase 3 and 9 activities in western blot analyses of the brain cortex were also decreased by MEL and Se treatments. In conclusion, in our diabetes experimental model, TRPM2 and TRPV1 channels are involved in the Ca 2+ entry-induced neuronal death and modulation of this channel activity by MEL and Se treatment may account for their neuroprotective activity against apoptosis and Ca 2+ entry. Graphical Abstract Possible molecular pathways of involvement of melatonin and selenium in diabetes-induced apoptosis, oxidative stress, and calcium accumulation through TRPM2 and TRPV1 channels in the hippocampus and DRG neurons of rats. The TRPM2 channel is activated by ADP-ribose and oxidative stress although it is inhibited by ACA. The TRPV1 channel is activated by oxidative stress and capsaicin and it is blocked by capsazepine (CPZ). Diabetes can result in augmented ROS release in hippocampal and DRG neurons through polyol reactions, leading to Ca 2+ uptake through TRPM2 and TRPV1 channels. Mitochondria were reported to accumulate Ca 2+ provided intracellular Ca 2+ rises, thereby leading to the depolarization of mitochondrial membranes and release of apoptosis-inducing factors such as caspase 3 and caspase 9. Melatonin and selenium reduce TRPM2 and TRPV1 channel activation through the modulation of polyol oxidative reactions and selenium-dependent glutathione peroxidase (GSH-Px) antioxidant pathways.

Oxidation and mobilization of selenium by nitrate in irrigation drainage

USGS Publications Warehouse

Wright, W.G.

1999-01-01

Selenium (Se) can be oxidized by nitrate (NO3-) from irrigation on Cretaceous marine shale in western Colorado. Dissolved Se concentrations are positively correlated with dissolved NO3- concentrations in surface water and ground water samples from irrigated areas. Redox conditions dominate in the mobilization of Se in marine shale hydrogeologic settings; dissolved Se concentrations increase with increasing platinum-electrode potentials. Theoretical calculations for the oxidation of Se by NO3- and oxygen show favorable Gibbs free energies for the oxidation of Se by NO3-, indicating NO3- can act as an electron acceptor for the oxidation of Se. Laboratory batch experiments were performed by adding Mancos Shale samples to zero- dissolved-oxygen water containing 0, 5, 50, and 100 mg/L NO3- as N (mg N/L). Samples were incubated in airtight bottles at 25??C for 188 d; samples collected from the batch experiment bottles show increased Se concentrations over time with increased NO3- concentrations. Pseudo first-order rate constants for NO3- oxidation of Se ranged from 0.0007 to 0.0048/d for 0 to 100 mg N/L NO3- concentrations, respectively. Management of N fertilizer applications in Cretaceous shale settings might help to control the oxidation and mobilization of Se and other trace constituents into the environment.

An Overview of Selenium Uptake, Metabolism, and Toxicity in Plants

PubMed Central

Gupta, Meetu; Gupta, Shikha

2017-01-01

Selenium (Se) is an essential micronutrient for humans and animals, but lead to toxicity when taken in excessive amounts. Plants are the main source of dietary Se, but essentiality of Se for plants is still controversial. However, Se at low doses protects the plants from variety of abiotic stresses such as cold, drought, desiccation, and metal stress. In animals, Se acts as an antioxidant and helps in reproduction, immune responses, thyroid hormone metabolism. Selenium is chemically similar to sulfur, hence taken up inside the plants via sulfur transporters present inside root plasma membrane, metabolized via sulfur assimilatory pathway, and volatilized into atmosphere. Selenium induced oxidative stress, distorted protein structure and function, are the main causes of Se toxicity in plants at high doses. Plants can play vital role in overcoming Se deficiency and Se toxicity in different regions of the world, hence, detailed mechanism of Se metabolism inside the plants is necessary for designing effective Se phytoremediation and biofortification strategies. PMID:28123395

Differential effects of selenite and selenate on human melanocytes, keratinocytes, and melanoma cells.

PubMed

Bandura, Laura; Drukala, Justyna; Wolnicka-Glubisz, Agnieszka; Björnstedt, Mikael; Korohoda, Wlodzimierz

2005-04-01

Among the substances that attracted the attention of oncologists in recent years are selenium-containing compounds, both inorganic and organic. Several epidemiological studies have shown an inverse correlation between selenium intake and cancer incidence. In the experiments reported here, we compared the effects of 2 inorganic selenium-containing salts that differed in the level of selenium oxidation, selenite IV and selenate VI. We tested the effects of these 2 compounds on cell survival and growth, cell cycle processing, cell morphology, cytoskeleton, and lipid peroxidation in 3 human skin cell types: normal keratinocytes, melanocytes, and human melanoma cell line HTB140. The different effects of selenite and selenate on the viability, growth, and morphology of normal cells and tumor cells are reported and provide a base for future research and treatment of some neoplastic diseases. The attention is paid to cell apoptosis induced by selenite and not by selenate, and the effects of tested substances on thioredoxin reductase system are postulated.

Indirect spectrophotometric determination of ultra trace amounts of selenium based on dispersive liquid-liquid microextraction-solidified floating organic drop.

PubMed

Haji Shabani, Ali Mohammad; Dadfarnia, Shayessteh; Nozohor, Mahnaz

2013-12-01

A novel dispersive liquid-liquid microextraction-solidified floating organic drop (DLLME-SFOD) method combined with fiber optic-linear array detection spectrophotometry has been developed for the indirect determination of selenium. The method is based on the oxidation of the I(-) to iodine by inorganic Se(IV). The produced I2 reacts with the excess of I(-) ions in acidic media to give triiodide ions. The I3(-) is then extracted into 1-undecanol by DLLME-SFOD upon the formation of an ion pair with cetyltrimethylammonium cation. The extracted ion pair is determined by measuring its absorption at 360 nm. The absorbance signal is proportional to the selenium concentration in the aqueous phase. Under optimum conditions, the method provided an enrichment factor of 250 with a detection limit of 16.0 μg L(-1) and a linear dynamic range of 40.0-1000.0 μg L(-1). The relative standard deviation was found to be 2.1% (n=7) at 100.0 μg L(-1) concentration level. The method was successfully applied to th e determination of selenium in water samples and selenium plus tablet. Copyright © 2013 Elsevier B.V. All rights reserved.

L-Selenomethionine Does not Protect Against Testosterone Plus 17β-Estradiol-Induced Oxidative Stress and Pre-Neoplastic Lesions in the Prostate of NBL Rats

PubMed Central

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 one 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 Nbl/Crl rats treated with T+E2 for 16 weeks. 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 and mRNA expression were induced by T+E2 (p<0.05–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. PMID:24773027

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

PubMed

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.

The oxidative damage and disbalance of calcium homeostasis in brain of chicken induced by selenium deficiency.

PubMed

Xu, Shi-Wen; Yao, Hai-Dong; Zhang, Jian; Zhang, Zi-Wei; Wang, Jin-Tao; Zhang, Jiu-Li; Jiang, Zhi-Hui

2013-02-01

Dietary selenium (Se) deficiency can influence the function of the brain. Our objective was to investigate the effects of Se deficiency on oxidative damage and calcium (Ca) homeostasis in brain of chicken. In the present study, 1-day-old chickens were fed either a commercial diet (as control group) with 0.15 mg/kg Se or a Se-deficient diet (as L group) with 0.033 mg/kg Se for 75 days. Then, brain injury biomarkers were examined, including histological analysis, ultrastructure assay, and apoptosis assay. We also examined the effect of Se deficiency on the Se-containing antioxidative enzyme glutathione peroxidase (GSH-Px), the level of glutathione (GSH), and the Ca homeostasis in brain of chicken. The results showed that the levels of Se and GSH and activity of GSH-Px are seriously reduced by 33.8-96 % (P < 0.001), 24.51-27.84 % (P < 0.001), and 20.70-64.24 % (P < 0.01), respectively. In the present study, we also perform histological analysis and ultrastructure assay and find that Se deficiency caused disorganized histological structure, damage to the mitochondria, fusion of nuclear membrane and nucleus shrinkage, higher apoptosis rate (P < 0.001), and increase of Ca homeostasis (P < 0.05 or P < 0.01 or P < 0.001) in the brain of chicken. In conclusion, the results demonstrated that Se deficiency induced oxidative damage and disbalance of Ca homeostasis in the brain of chicken. Similar to mammals, chickens brain is also extremely susceptible to oxidative damage and selenium deficiency.

Role of selenium toxicity and oxidative stress in aquatic birds

USGS Publications Warehouse

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 hepatic GSH peroxidase, depletion of hepatic protein bound thiols and total thiols, but a small increase in GSH. Diving ducks in the San Francisco Bay area exhibited a positive correlation between hepatic Se concentration and GSH peroxidase activity (r=0.63, P<0.05), but a negative correlation between hepatic Se and GSH concentration (r=0.740, P<0.05). In willets (Catoptrophorus semipalmatus) from the San Diego area, positive correlations occurred between hepatic Se concentration and GSSG (r=0.70, P<0.001), GSSG:GSH ratio, and TBARS. In emperor geese (Chen canagica) from western Alaska, blood levels of up to 9.4 ppm occurred and were associated with increased plasma GSH peroxidase activity (r=0.62, P<0.001), but with decreased plasma GSSG reductase activity. When evaluating Se toxicity, interactive nutritional factors, including other elements and dietary protein, should also be taken into consideration. Further studies are needed to examine the relationship between different forms of environmentally occurring selenium, arsenic and mercury on reproduction, hepatotoxicity and immune function of aquatic birds. Further selenium nutritional interaction studies may also help to illucidate the mechanism of selenium induced teratogenesis, by optimizing GSH and other antioxidant defense mechanisms in a manner that would stabilize or raise the cell's threshold for susceptibility to toxic attack from excess selenium. It is concluded that Se-related manifestations of oxidative stress may serve as useful bioindicators of Se exposure and toxicity in wild aquatic birds.

Selenium Alleviates Oxidative Stress and Lung Damage Induced by Aluminum Chloride in Adult Rats: Biochemical and Histological Approach.

PubMed

Ghorbel, Imen; Elwej, Awatef; Chaabane, Mariem; Jamoussi, Kamel; Mnif, Hela; Boudawara, Tahia; Zeghal, Najiba

2017-03-01

Our study pertains to the potential ability of selenium, used as a nutritional supplement, to alleviate oxidative stress induced by aluminum chloride in the lung tissue. Rats have received during 21 days either aluminum chloride (AlCl 3 ) (400 ppm) via drinking water, AlCl 3 associated with Na 2 SeO 3 (0.5 mg/kg of diet), or only Na 2 SeO 3 . Exposure of rats to AlCl 3 induced lung oxidative stress with an increase of malondialdehyde, hydrogen peroxide, and protein carbonyls levels. An alteration of lactate dehydrogenase activities and antioxidant redox status, enzymatic (catalase, superoxide dismutase, and glutathione peroxidase), and non-enzymatic (non-protein thiols, glutathione, metallothionein, and vitamin C) was also observed. These biochemical modifications were substantiated by histopathological data showing alveolar edema, a large number of hemosiderin-laden macrophages, and emphysema. Se supplementation attenuated the levels of oxidative stress by restoring antioxidant state and improved lung histological damage. Our results revealed that Se, a trace element with antioxidant properties, was effective in preventing lung damage.

Antioxidant Intake and Pancreatic Cancer Risk: the VITamins And Lifestyle (VITAL) Study

PubMed Central

Han, Xuesong; Li, Jingjing; Brasky, Theodore M.; Xun, Pengcheng; Stevens, June; White, Emily; Gammon, Marilie D.; He, Ka

2012-01-01

Background Oxidative stress causes damage to many components of human cells (i.e., proteins, lipids, and DNA) and is involved in carcinogenesis. Nutrients with antioxidant properties may protect against oxidative stress. We examined intake of antioxidants from diet and supplements in relation to pancreatic cancer risk among participants of the VITamins And Lifestyle (VITAL) Study. Methods Participants were 77,446 men and women, ages 50–76 years, who were residents of western Washington State and completed a baseline questionnaire between 2000 and 2002. Participants reported usual diet over the past year and use of supplements over the past 10 years, in addition to demographic and lifestyle factors. During a median follow-up of 7.1 years, 184 participants developed pancreatic adenocarcinoma. Cox regression models were used to estimate multivariable-adjusted hazard ratios (HR) and 95% confidence intervals (CI) for seven antioxidants: β-carotene, lutein and zeaxanthin, lycopene, vitamin C, vitamin E, selenium and zinc. Results We observed an inverse association between dietary selenium and pancreatic cancer risk (medium vs. low intake: HR 0.58, 95% CI 0.35–0.94; high vs. low intake: HR 0.44, 95% CI 0.23–0.85; p-trend = 0.01); however, when supplemental and dietary exposures were combined, the association was no longer statistically significant. Conclusions Dietary selenium intake is inversely associated with risk of pancreatic cancer and the observed association is attenuated by selenium supplementation. PMID:23280534

Selenium contaminated waters: An overview of analytical methods, treatment options and recent advances in sorption methods.

PubMed

Santos, Sílvia; Ungureanu, Gabriela; Boaventura, Rui; Botelho, Cidália

2015-07-15

Selenium is an essential trace element for many organisms, including humans, but it is bioaccumulative and toxic at higher than homeostatic levels. Both selenium deficiency and toxicity are problems around the world. Mines, coal-fired power plants, oil refineries and agriculture are important examples of anthropogenic sources, generating contaminated waters and wastewaters. For reasons of human health and ecotoxicity, selenium concentration has to be controlled in drinking-water and in wastewater, as it is a potential pollutant of water bodies. This review article provides firstly a general overview about selenium distribution, sources, chemistry, toxicity and environmental impact. Analytical techniques used for Se determination and speciation and water and wastewater treatment options are reviewed. In particular, published works on adsorption as a treatment method for Se removal from aqueous solutions are critically analyzed. Recent published literature has given particular attention to the development and search for effective adsorbents, including low-cost alternative materials. Published works mostly consist in exploratory findings and laboratory-scale experiments. Binary metal oxides and LDHs (layered double hydroxides) have presented excellent adsorption capacities for selenium species. Unconventional sorbents (algae, agricultural wastes and other biomaterials), in raw or modified forms, have also led to very interesting results with the advantage of their availability and low-cost. Some directions to be considered in future works are also suggested. Copyright © 2015 Elsevier B.V. All rights reserved.

Selenium and inflammatory bowel disease.

PubMed

Kudva, Avinash K; Shay, Ashley E; Prabhu, K Sandeep

2015-07-15

Dietary intake of the micronutrient selenium is essential for normal immune functions. Selenium is cotranslationally incorporated as the 21st amino acid, selenocysteine, into selenoproteins that function to modulate pathways involved in inflammation. Epidemiological studies have suggested an inverse association between selenium levels and inflammatory bowel disease (IBD), which includes Crohn's disease and ulcerative colitis that can potentially progress to colon cancer. However, the underlying mechanisms are not well understood. Here we summarize the current literature on the pathophysiology of IBD, which is multifactorial in origin with unknown etiology. We have focused on a few selenoproteins that mediate gastrointestinal inflammation and activate the host immune response, wherein macrophages play a pivotal role. Changes in cellular oxidative state coupled with altered expression of selenoproteins in macrophages drive the switch from a proinflammatory phenotype to an anti-inflammatory phenotype to efficiently resolve inflammation in the gut and restore epithelial barrier integrity. Such a phenotypic plasticity is accompanied by changes in cytokines, chemokines, and bioactive metabolites, including eicosanoids that not only mitigate inflammation but also partake in restoring gut homeostasis through diverse pathways involving differential regulation of transcription factors such as nuclear factor-κB and peroxisome proliferator-activated receptor-γ. The role of the intestinal microbiome in modulating inflammation and aiding in selenium-dependent resolution of gut injury is highlighted to provide novel insights into the beneficial effects of selenium in IBD. Copyright © 2015 the American Physiological Society.

Determination of the distribution and speciation of selenium in an argillaceous sample using chemical extractions and post-extractions analyses: application to the hydrogeological experimental site of Poitiers.

PubMed

Bassil, Joseph; Naveau, Aude; Bueno, Maïté; Di Tullo, Pamela; Grasset, Laurent; Kazpard, Véronique; Razack, Moumtaz

2016-05-01

To better understand selenium's dynamics in environmental systems, the present study aims to investigate selenium speciation and distribution in black argillaceous sediments, partially fulfilling karstic cavities into the Hydrogeological Experimental Site of Poitiers. These sediments are suspected to be responsible for selenium concentrations exceeding the European Framework Directive's drinking water limit value (10 μg L(-1)) in some specific wells. A combination of a sequential extractions scheme and single parallel extractions was thus applied on a representative argillaceous sample. Impacts of the extractions on mineral dissolution and organic matter mobilization were followed by quantifying major cations and total organic carbon (TOC) in the aqueous extracts. The nature of the released organic matter was characterized using thermochemolysis coupled with gas chromatography-mass spectrometry (GC-MS). About 10 % of selenium from the black argillaceous studied matrix could be defined as 'easily mobilizable' when the majority (around 70 %) revealed associated with the aliphatic and alkaline-soluble organic matter's fraction (about 20 %). In these fractions, selenium speciation was moreover dominated by oxidized species including a mixture of Se(VI) (20-30 %) and Se(IV) (70-80 %) in the 'easily mobilizable' fraction, while only Se(IV) was detected in alkaline-soluble organic matter fraction.

Effects of high doses of selenium, as sodium selenite, in septic shock: a placebo-controlled, randomized, double-blind, phase II study

PubMed Central

Forceville, Xavier; Laviolle, Bruno; Annane, Djillali; Vitoux, Dominique; Bleichner, Gérard; Korach, Jean-Michel; Cantais, Emmanuel; Georges, Hugues; Soubirou, Jean-Louis; Combes, Alain; Bellissant, Eric

2007-01-01

Introduction Sepsis is associated with the generation of oxygen free radicals and (lacking) decreased selenium plasma concentrations. High doses of sodium selenite might reduce inflammation by a direct pro-oxidative effect and may increase antioxidant cell capacities by selenium incorporation into selenoenzymes. We investigated the effects of a continuous administration of high doses of selenium in septic shock patients. Methods A prospective, multicentre, placebo-controlled, randomized, double-blind study was performed with an intention-to-treat analysis in severe septic shock patients with documented infection. Patients received, for 10 days, selenium as sodium selenite (4,000 μg on the first day, 1,000 μg/day on the nine following days) or matching placebo using continuous intravenous infusion. The primary endpoint was the time to vasopressor therapy withdrawal. The duration of mechanical ventilation, the mortality rates in the intensive care unit, at hospital discharge, and at 7, 14, 28 and 180 days and 1 year after randomization, and adverse events were recorded. Results Sixty patients were included (placebo, n = 29; selenium, n = 31). The median time to vasopressor therapy withdrawal was 7 days in both groups (95% confidence interval = 5–8 and 6–9 in the placebo and selenium groups, respectively; log-rank, P = 0.713). The median duration of mechanical ventilation was 14 days and 19 days in the placebo and selenium groups, respectively (P = 0.762). Mortality rates did not significantly differ between groups at any time point. Rates of adverse events were similar in the two groups. Conclusion Continuous infusion of selenium as sodium selenite (4,000 μg on the first day, 1,000 μg/day on the nine following days) had no obvious toxicity but did not improve the clinical outcome in septic shock patients. Trial Registration = NCT00207844. PMID:17617901

Automated determinations of selenium in thermal power plant wastewater by sequential hydride generation and chemiluminescence detection.

PubMed

Ezoe, Kentaro; Ohyama, Seiichi; Hashem, Md Abul; Ohira, Shin-Ichi; Toda, Kei

2016-02-01

After the Fukushima disaster, power generation from nuclear power plants in Japan was completely stopped and old coal-based power plants were re-commissioned to compensate for the decrease in power generation capacity. Although coal is a relatively inexpensive fuel for power generation, it contains high levels (mgkg(-1)) of selenium, which could contaminate the wastewater from thermal power plants. In this work, an automated selenium monitoring system was developed based on sequential hydride generation and chemiluminescence detection. This method could be applied to control of wastewater contamination. In this method, selenium is vaporized as H2Se, which reacts with ozone to produce chemiluminescence. However, interference from arsenic is of concern because the ozone-induced chemiluminescence intensity of H2Se is much lower than that of AsH3. This problem was successfully addressed by vaporizing arsenic and selenium individually in a sequential procedure using a syringe pump equipped with an eight-port selection valve and hot and cold reactors. Oxidative decomposition of organoselenium compounds and pre-reduction of the selenium were performed in the hot reactor, and vapor generation of arsenic and selenium were performed separately in the cold reactor. Sample transfers between the reactors were carried out by a pneumatic air operation by switching with three-way solenoid valves. The detection limit for selenium was 0.008 mg L(-1) and calibration curve was linear up to 1.0 mg L(-1), which provided suitable performance for controlling selenium in wastewater to around the allowable limit (0.1 mg L(-1)). This system consumes few chemicals and is stable for more than a month without any maintenance. Wastewater samples from thermal power plants were collected, and data obtained by the proposed method were compared with those from batchwise water treatment followed by hydride generation-atomic fluorescence spectrometry. Copyright © 2015 Elsevier B.V. All rights reserved.

Selenium toxicity: cause and effects in aquatic birds

USGS Publications Warehouse

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.

Effect of intraperitoneal selenium administration on liver glycogen levels in rats subjected to acute forced swimming.

PubMed

Akil, Mustafa; Bicer, Mursel; Kilic, Mehmet; Avunduk, Mustafa Cihat; Mogulkoc, Rasim; Baltaci, Abdulkerim Kasim

2011-03-01

There are a few of studies examining how selenium, which is known to reduce oxidative damage in exercise, influences glucose metabolism and exhaustion in physical activity. The present study aims to examine how selenium administration affects liver glycogen levels in rats subjected to acute swimming exercise. The study included 32 Sprague-Dawley type male rats, which were equally allocated to four groups: Group 1, general control; Group 2; selenium-supplemented control (6 mg/kg/day sodium selenite); Group 3, swimming control; Group 4, selenium-supplemented swimming (6 mg/kg/day sodium selenite). Liver tissue samples collected from the animals at the end of the study were fixed in 95% ethyl alcohol. From the tissue samples buried into paraffin, 5-µm cross-sections were obtained using a microtome, put on a microscope slide, and stained with PAS. Stained preparations were assessed using a Nikon Eclipse E400 light microscope. All images obtained with the light microscope were transferred to a PC and evaluated using Clemex PE 3.5 image analysis software. The highest liver glycogen levels were found in groups 1 and 2 (p < 0.05). The levels in group 4 were lower than those in groups 1 and 2 but higher than the levels in group 3 (p < 0.05). The lowest liver glycogen levels were obtained in group 3 (p < 0.05). Results of the study indicate that liver glycogen levels that decrease in acute swimming exercise can be restored by selenium administration. It can be argued that physiological doses of selenium administration can contribute to performance.

The Association between Selenium and Other Micronutrients and Thyroid Cancer Incidence in the NIH-AARP Diet and Health Study

PubMed Central

O’Grady, Thomas J.; Kitahara, Cari M.; DiRienzo, A. Gregory; Gates, Margaret A.

2014-01-01

Background Selenium is an essential trace element that is important for thyroid hormone metabolism and has antioxidant properties which protect the thyroid gland from oxidative stress. The association of selenium, as well as intake of other micronutrients, with thyroid cancer is unclear. Methods We evaluated associations of dietary selenium, beta-carotene, calcium, vitamin D, vitamin C, vitamin E, folate, magnesium, and zinc intake with thyroid cancer risk in the National Institutes of Health – American Association of Retired Persons Diet and Health Study, a large prospective cohort of 566,398 men and women aged 50–71 years in 1995–1996. Multivariable-adjusted Cox proportional hazards regression was used to examine associations between dietary intake of micronutrients, assessed using a food frequency questionnaire, and thyroid cancer cases, ascertained by linkage to state cancer registries and the National Death Index. Results With the exception of vitamin C, which was associated with an increased risk of thyroid cancer (HRQ5 vs Q1, 1.34; 95% CI, 1.02–1.76; Ptrend, <0.01), we observed no evidence of an association between quintile of selenium (HRQ5 vs Q1, 1.23; 95% CI, 0.92–1.65; Ptrend, 0.26) or other micronutrient intake and thyroid cancer. Conclusion Our study does not suggest strong evidence for an association between dietary intake of selenium or other micronutrients and thyroid cancer risk. More studies are needed to clarify the role of selenium and other micronutrients in thyroid carcinogenesis. PMID:25329812

Selenium isotope evidence for progressive oxidation of the Neoproterozoic biosphere

PubMed Central

Pogge von Strandmann, Philip A. E.; Stüeken, Eva E.; Elliott, Tim; Poulton, Simon W.; Dehler, Carol M.; Canfield, Don E.; Catling, David C.

2015-01-01

Neoproterozoic (1,000–542 Myr ago) Earth experienced profound environmental change, including ‘snowball' glaciations, oxygenation and the appearance of animals. However, an integrated understanding of these events remains elusive, partly because proxies that track subtle oceanic or atmospheric redox trends are lacking. Here we utilize selenium (Se) isotopes as a tracer of Earth redox conditions. We find temporal trends towards lower δ82/76Se values in shales before and after all Neoproterozoic glaciations, which we interpret as incomplete reduction of Se oxyanions. Trends suggest that deep-ocean Se oxyanion concentrations increased because of progressive atmospheric and deep-ocean oxidation. Immediately after the Marinoan glaciation, higher δ82/76Se values superpose the general decline. This may indicate less oxic conditions with lower availability of oxyanions or increased bioproductivity along continental margins that captured heavy seawater δ82/76Se into buried organics. Overall, increased ocean oxidation and atmospheric O2 extended over at least 100 million years, setting the stage for early animal evolution. PMID:26679529

Effect of bacoside A on brain antioxidant status in cigarette smoke exposed rats.

PubMed

Anbarasi, K; Vani, G; Balakrishna, K; Devi, C S Shyamala

2006-02-16

Free radicals mediated oxidative stress has been implicated in the pathogenesis of smoking-related diseases and antioxidant nutrients are reported to prevent the oxidative damage induced by smoking. Therefore, the present study was conducted to evaluate the antioxidant role of bacoside A (triterpenoid saponin isolated from Bacopa monniera) against chronic cigarette smoking induced oxidative damage in rat brain. Adult male albino rats were exposed to cigarette smoke for a period of 12 weeks and simultaneously administered with bacoside A (10 mg/kg b.w./day, p.o.). Antioxidant status of the brain was assessed from the levels of reduced glutathione, vitamin C, vitamin E, and vitamin A and the activities of superoxide dismutase, catalase, glutathione peroxidase and glutathione reductase. The levels of copper, iron, zinc and selenium in brain and serum ceruloplasmin activity were also measured. Oxidative stress was evident from the diminished levels of both enzymatic and non-enzymatic antioxidants. Alterations in the levels of trace elements with accumulation of copper and iron, and depletion of zinc and selenium were also observed. Bacoside A administration improved the antioxidant status and maintained the levels of trace elements. These results suggest that chronic cigarette smoke exposure enhances oxidative stress, thereby disturbing the tissue defense system and bacoside A protects the brain from the oxidative damage through its antioxidant potential.

Zinc Supplementation Alters Plasma Aluminum and Selenium Status of Patients Undergoing Dialysis: A Pilot Study

PubMed Central

Guo, Chih-Hung; Chen, Pei-Chung; Hsu, Guoo-Shyng W.; Wang, Chia-Liang

2013-01-01

End stage renal disease patients undergoing long-term dialysis are at risk for abnormal concentrations of certain essential and non-essential trace metals and high oxidative stress. We evaluated the effects of zinc (Zn) supplementation on plasma aluminum (Al) and selenium (Se) concentrations and oxidative stress in chronic dialysis patients. Zn-deficient patients receiving continuous ambulatory peritoneal dialysis or hemodialysis were divided into two groups according to plasma Al concentrations (HA group, Al > 50 μg/L; and MA group, Al > 30 to ≤ 50 μg/L). All patients received daily oral Zn supplements for two months. Age- and gender-matched healthy individuals did not receive Zn supplement. Clinical variables were assessed before, at one month, and after the supplementation period. Compared with healthy subjects, patients had significantly lower baseline plasma Se concentrations and higher oxidative stress status. After two-month Zn treatment, these patients had higher plasma Zn and Se concentrations, reduced plasma Al concentrations and oxidative stress. Furthermore, increased plasma Zn concentrations were related to the concentrations of Al, Se, oxidative product malondialdehyde (MDA), and antioxidant enzyme superoxide dismutase activities. In conclusion, Zn supplementation ameliorates abnormally high plasma Al concentrations and oxidative stress and improves Se status in long-term dialysis patients. PMID:23609777

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

PubMed

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 (<10μM) however no effect was noted on either FCFc or Bax at concentrations above 10μM. The inhibition of antioxidant systems in non-cancerous cells by Auranofin is strongly dose dependent, and this inhibition can be altered by 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.

Clinical and Metabolic Response to Selenium Supplementation in Pregnant Women at Risk for Intrauterine Growth Restriction: Randomized, Double-Blind, Placebo-Controlled Trial.

PubMed

Mesdaghinia, Elaheh; Rahavi, Azam; Bahmani, Fereshteh; Sharifi, Nasrin; Asemi, Zatollah

2017-07-01

Data on the effects of selenium supplementation on clinical signs and metabolic profiles in women at risk for intrauterine growth restriction (IUGR) are scarce. This study was designed to assess the effects of selenium supplementation on clinical signs and metabolic status in pregnant women at risk for IUGR. This randomized double-blind placebo-controlled clinical trial was performed among 60 women at risk for IUGR according to abnormal uterine artery Doppler waveform. Participants were randomly assigned to intake either 100 μg selenium supplements as tablet (n = 30) or placebo (n = 30) for 10 weeks between 17 and 27 weeks of gestation. After 10 weeks of selenium administration, a higher percentage of women in the selenium group had pulsatility index (PI) of <1.45) (P = 0.002) than of those in the placebo group. In addition, changes in plasma levels of total antioxidant capacity (TAC) (P < 0.001), glutathione (GSH) (P = 0.008), and high-sensitivity C-reactive protein (hs-CRP) (P = 0.004) in the selenium group were significant compared with the placebo group. Additionally, selenium supplementation significantly decreased serum insulin (P = 0.02), homeostasis model of assessment-estimated insulin resistance (HOMA-IR) (P = 0.02), and homeostatic model assessment for B-cell function (HOMA-B) (P = 0.02) and significantly increased quantitative insulin sensitivity check index (QUICKI) (P = 0.04) and HDL-C levels (P = 0.02) compared with the placebo. We did not find any significant effect of selenium administration on malondialdehyde (MDA), nitric oxide (NO), fasting plasma glucose (FPG), and other lipid profiles. Overall, selenium supplementation in pregnant women at risk for IUGR resulted in improved PI, TAC, GSH, hs-CRP, and markers of insulin metabolism and HDL-C levels, but it did not affect MDA, NO, FPG, and other lipid profiles.Clinical trial registration number http://www.irct.ir : IRCT201601045623N64.

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

PubMed Central

Ojeda, María Luisa; Vázquez, Beatriz; Nogales, Fátima; Murillo, María Luisa; Carreras, Olimpia

2009-01-01

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. PMID:19742151

Effect of vitamin E supplementation on arsenic induced alteration in blood biochemical profile, oxidant/antioxidant status, serum cortisol level and retention of arsenic and selenium in goats.

PubMed

Mohanta, Ranjan Kumar; Garg, Anil Kumar; Dass, Ram Sharan

2015-01-01

Arsenic (As) exerts oxidative stress with depletion of body selenium in monogastric animals. But in ruminants this fact is not yet verified. Vitamin E is an effective dietary antioxidant. Thus, in this experiment, the protective effect of vitamin E against arsenic toxicity induced by sodium arsenite (60mg As/kg diet) was investigated in goat kids. For this, 21 male kids were divided into three equal groups and fed either basal diet as such (control), or supplemented with 60mg As/kg diet and 60mg As/kg diet+250IU vitamin E/kg diet for 180 days. Vitamin E supplementation alleviated the toxic effects caused by arsenic on serum alanine aminotransferase and aspartate aminotransferase and lipid peroxidation. It also prevented the depletion of reduced glutathione content and reduction in activity of catalase, superoxide dismutase and glutathione-s-transferase in erythrocytes resulted from arsenic intoxication. The elevated levels of arsenic and reduced levels of selenium in the serum and tissues in arsenic treated animals were attenuated by vitamin E supplementation, though not completely. However, serum cortisol level was not affected by arsenic. It was concluded that arsenic exerts cortisol independent stressor mechanism and supplementation of vitamin E at a level of 250IU/kg diet was partially effective in reducing tissue accumulation of arsenic in the body and protect the kids from oxidative stress induced by arsenic. Copyright © 2014 Elsevier GmbH. All rights reserved.

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

PubMed Central

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

Selenium and sulphur derivatives of hydroxytyrosol: inhibition of lipid peroxidation in liver microsomes of vitamin E-deficient rats.

PubMed

Rodríguez-Gutiérrez, Guillermo; Rubio-Senent, Fátima; Gómez-Carretero, Antonio; Maya, Inés; Fernández-Bolaños, Juan; Duthie, Garry G; de Roos, Baukje

2018-05-28

The objective of this study was to evaluate the capacity of modified phenols synthesized from hydroxytyrosol, a natural olive oil phenol, specifically those containing a selenium or sulphur group, to inhibit lipid peroxidation. The compounds' abilities to inhibit lipid peroxidation in liver microsomes obtained from vitamin E-deficient rats were compared to hydroxytyrosol. All synthetic compounds had a significant higher ability to inhibit lipid peroxidation than hydroxytyrosol. Selenium derivates displayed a higher antioxidant activity than sulphur derivatives. In addition, the antioxidant activity increased with a higher number of heteroatoms in the hydroxytyrosol molecular structure. The study shows, for the first time, the ability of synthetic compounds, derived from the most active phenol present in olives in free form (hydroxytyrosol), and containing one or two atoms of sulphur or selenium, to inhibit the lipid peroxidation of vitamin E-deficient microsomes. The antioxidant activity of five thioureas, a disulfide, a thiol, three selenoureas, a diselenide, and a selenonium were evaluated and the results showed a higher inhibition of lipid peroxidation than the natural phenol. Selenium and sulphur derivatives of hydroxytyrosol are novel antioxidants with the potential to supplement the lack of vitamin E in the diet as natural alternatives for the prevention of diseases related to oxidative damage.

Preparation of cuxinygazsen precursor films and powders by electroless deposition

DOEpatents

Bhattacharya, Raghu N.; Batchelor, Wendi Kay; Wiesner, Holm; Ramanathan, Kannan; Noufi, Rommel

1999-01-01

A method for electroless deposition of Cu.sub.x In.sub.y Ga.sub.z Se.sub.n (x=0-2, y=0-2, z=0-2, n=0-3) precursor films and powders onto a metallic substrate comprising: preparing an aqueous bath solution of compounds selected from the group consisting of: I) a copper compound, a selenium compound, an indium compound and gallium compound; II) a copper compound, a selenium compound and an indium compound; III) a selenium compound, and indium compound and a gallium compound; IV) a selenium compound and a indium compound; and V) a copper compound and selenium compound; each compound being present in sufficient quantity to react with each other to produce Cu.sub.x In.sub.y Ga.sub.z Se.sub.n (x=0-2, y=0-2, z=0-2, n=0-3); adjusting the pH of the aqueous bath solution to an acidic value by the addition of a dilute acid; and initiating an electroless reaction with an oxidizing counterelectrode for a sufficient time to cause a deposit of Cu.sub.x In.sub.y Ga.sub.z Se.sub.n (x=0-2, y=0-2, z=0-2, n=0-3) from the aqueous bath solution onto a metallic substrate.

Protection of methamphetamine nigrostriatal toxicity by dietary selenium.

PubMed

Kim, H C; Jhoo, W K; Choi, D Y; Im, D H; Shin, E J; Suh, J H; Floyd, R A; Bing, G

1999-12-18

Multiple dose administration of methamphetamine (MA) results in long-lasting toxic effects in the nigrostriatal dopaminergic system. These effects are considered to be primarily due to oxidative damage mediated by increased production of hydrogen peroxide or other reactive oxygen species in the dopaminergic system. The present study was designed to determine the protective effects of dietary antioxidant selenium on MA-induced neurotoxicity in the nigrostriatal dopaminergic system. Male C57BL/6J mice were fed either selenium-deficient (< 0.01 ppm Se) or selenium-replete (0.2 ppm Se) diets for 90 days. MA treatment decreased the dopamine (DA) levels in the striatum and substantia nigra (SN) of both Se-replete and Se-deficient animals. However, in Se-replete animals, this DA depletion was significantly attenuated in both the striatum and SN. A novel observation is that MA administration resulted in increased activity of Cu,Zn-SOD in the brains of both Se-deficient and Se-replete animals. However, MA administration to Se-deficient animals exhibited a higher Cu,Zn-SOD activity in the nigrostriatal system than the control animals. Elevated malondialdehyde (MDA) levels in the striatum and SN were also observed in Se-deficient MA-treated animals. Se repletion significantly increased the glutathione peroxidase (GPx) activity and the ratio of reduced glutathione (GSH)/oxidized glutathione (GSSG) in the MA-treated animals. In conclusion, we have shown that dietary Se attenuated methamphetamine neurotoxicity and that this protection involves GPx-mediated antioxidant mechanisms. Even though Cu,Zn-SOD activity was significantly elevated by MA treatment, the role of this enzyme in MA-mediated neurotoxicity is not yet clear.

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

PubMed

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.

Nanoparticles of selenium as species with stronger physiological effects in sheep in comparison with sodium selenite.

PubMed

Sadeghian, Sirous; Kojouri, Gholam Ali; Mohebbi, Abdonnaser

2012-06-01

The present study was designed to compare the effects of nano red selenium and sodium selenite on the antioxidative activities of neutrophils and the hematological parameters in sheep. Fifteen sheep were randomly allocated into three groups. Groups 1 and 2 received selenium nanoparticles orally at 1 mg/kg and sodium selenite at 1 mg Se/kg for 10 consecutive days; group 3 served as the control. To assess the degrees of oxidative stress and of lipid peroxidation of the cellular membranes, the levels of thiobarbituric acid reactive substances (TBARS) were determined in serum samples that were collected at different supplementation intervals, i.e., after 0, 10, 20, and 30 days. In addition, hematological parameters in the serum samples were measured by routine procedures. It was found that TBARS levels in groups 1 and 2 were significantly higher on days 20 and 30 compared to the basal level on day 0. It was also found that on day 30, the TBARS activities in both treated groups were significantly higher than those of the controls (P < 0.05). These findings may explain the seemingly paradoxical effects of supplemental selenium on the indicators of oxidative stress, as the levels of TBARS were generally expected to decrease in the presence of selenium. There were no significant differences between the PCV and RBC values in the three groups. The white blood cell count (WBC) in group 1 showed a significant increase on days 20 and 30 in comparison with the control group. However, in group 2, there was a significant increase of the WBC value just on day 20 in comparison with the control group. Also, there were significant increases of the neutrophil counts and significant decreases of the lymphocyte counts on day 10 in group 1, in comparison with those in group 2 and controls, and on days 20 and 30 in groups 1 and 2 in comparison with those in the control group.

Effects of selenium on ischaemia-reperfusion injury in a rat testis model.

PubMed

Kara, Ö; Sari, E; Akşit, H; Yay, A; Akşit, D; Dönmez, M I

2016-12-01

Selenium is shown to have beneficial effects on ischaemia-reperfusion (IR) injury. Our aim was to assess the effects of selenium on IR-induced testicular damage in terms of biochemical and histopathological evaluation. A total of 32 rats were randomised into four groups: control, IR, IR + selenium (IR + S) and S. Detorsion was applied after 3 h of torsion. Testicular tissue superoxide dismutase (SOD), glutathione (GSH), malondialdehyde (MDA), total antioxidant capacity (TAC) and DNA fragmentation levels were determined. Testicular tissue samples were examined by histopathological examination and terminal deoxynucleotidyl transferase dUTP nick end-labelling staining. The control, IR and IR + S groups had higher SOD values compared with the S group; SOD levels of the control and IR + S groups were higher than those of the IR group (P < 0.05). Further, MDA levels of the IR group were higher than those in the other three groups (P < 0.05). The IR group revealed lower TAC levels than the three groups (P < 0.05 for all). GSH levels of the IR group were significantly lower than those in the other three groups (P < 0.05 for all). In contrast, GSH levels of the IR + S group increased compared with those of the S group. The IR group had more DNA fragmentation than the control and S groups (P < 0.05). It is concluded that selenium possibly reduces oxidative stress and apoptosis caused by testicular IR injury in rats. The testicular protective effect of selenium appears to be mediated through its anti-apoptotic and antioxidative effects. However, selenium does not affect DNA fragmentation. © 2016 Blackwell Verlag GmbH.

Investigation of biotransformation of selenium in plants using spectrometric methods

NASA Astrophysics Data System (ADS)

Ruszczyńska, Anna; Konopka, Anna; Kurek, Eliza; Torres Elguera, Julio Cesar; Bulska, Ewa

2017-04-01

The aim of this research was to study the processes of biotransformation of selenium in plants such as garlic, radish sprouts and sunflower sprouts via identification of selenium-containing compounds as metabolites of inorganic selenium using mass spectrometry. Speciation analysis of selenium in extracts from plant samples was performed with the use of hyphenated high performance liquid chromatography and inductively coupled plasma mass spectrometry (HPLC-ICP-MS) method. Matching the retention times of sample compounds with standards allowed identification of Se-methyl-selenocysteine, selenomethionine, γ-glutamyl-Se-methylselenocysteine and inorganic SeO32 -. However, registered chromatograms included additional 82Se signals which couldn't be identified due to the lack of standards. Qualitative analysis of unknown compounds was achieved using high-resolution mass spectrometer equipped with mass analyzer Orbitrap coupled to high performance liquid chromatography. Since selenium has six stable isotopes of different abundance in nature, mass spectra of have a very characteristic isotopic pattern. In order to elucidate the structure of unknown Se compounds, selected ions were subjected to the fragmentation. Following selenocompounds were identified an inorganic selenium metabolites in garlic, sunflower sprouts and/or radish sprouts: selenohomolanthionine, Se-methyl-selenocysteine, selenomethionine, selenomethionine oxide, deaminohydroxy-selenohomolanthionine, N-acetylcysteine-selenomethionine, γ-glutamyl-Se-methyl-selenocysteine, methylseleno-Se-pentose-hexose, Se-methyl-selenoglutathione, 2,3-dihydroxy-propionyl-selenocysteine-cysteine, methyltio-selenoglutathione, 2,3-dihydroxypropionyl-selenolanthionine and two Se-containing compounds with proposed molecular formula C10H18N2O6Se and C10H13N5O3Se. Moreover, the structure was proposed for one selenocompound found in sunflower sprouts which has not been reported so far.

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

PubMed

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.

Role of Trace Elements for Oxidative Status and Quality of Human Sperm.

PubMed

Nenkova, Galina; Petrov, Lubomir; Alexandrova, Albena

2017-08-04

Oxidative stress affects sperm quality negatively. To maintain the pro/antioxidant balance, some metal ions (e.g. copper, zink, iron, selenium), which are co-factors of the antioxidant enzymes, are essential. However, iron and copper could act as prooxidants inducing oxidative damage of spermatozoa. To reveal a possible correlation between the concentrations of some metal ions (iron, copper, zinc, and selenium) in human seminal plasma, oxidative stress, assessed by malondialdehyde and total glutathione levels, and semen quality, assessed by the parameters count, motility, and morphology. Descriptive study. The semen analysis for volume, count, and motility was performed according to World Health Organization (2010) guidelines, using computer-assisted semen analysis. For the determination of spermatozoa morphology, a SpermBlue staining method was applied. Depending on their parameters, the sperm samples were categorized into normozoospermic, teratozoospermic, asthenoteratozoospermic, and oligoteratozoospermic. The seminal plasma content of iron, copper, zinc, and selenium was estimated by atomic absorption spectroscopy. The malondialdehyde and total glutathione levels were quantified spectrophotometrically. In the groups with poor sperm quality, the levels of Fe were higher, whereas those of Zn and Se were significantly lower than in the normozoospermic group. In all groups with poor sperm quality, increased levels of malondialdehyde and decreased glutathione levels were detected as evidence of oxidative stress occurrence. All these differences are most pronounced in the asthenoteratozoospermic group where values differ nearly twice as much compared to the normozoospermic group. The Fe concentration correlated positively with the malondialdehyde (r=0.666, p=0.018), whereas it showed a negative correlation with the level of total glutathione (r=-0.689, p=0.013). The total glutathione level correlated positively with the sperm motility (r=0.589, p=0.044). The elevated levels of Fe and the reduced Se levels are associated with sperm damage. The changes in the concentrations of the trace elements in human seminal plasma may be related to sperm quality since they are involved in the maintenance of the pro-/antioxidative balance in ejaculate.

Improvement of antioxidant status after Brazil nut intake in hypertensive and dyslipidemic subjects.

PubMed

Huguenin, Grazielle V B; Oliveira, Glaucia M M; Moreira, Annie S B; Saint'Pierre, Tatiana D; Gonçalves, Rodrigo A; Pinheiro-Mulder, Alessandra R; Teodoro, Anderson J; Luiz, Ronir R; Rosa, Glorimar

2015-05-29

To investigate the effect of partially defatted Granulated Brazil nut (GBN) on biomarkers of oxidative stress and antioxidant status of hypertensive and dyslipidemic patients on nutrition and drug approaches. Ninety one hypertensive and dyslipidemic subjects of both genders (51.6 % men), mean age 62.1 ± 9.3 years, performed a randomized crossover trial, double-blind, placebo controlled. Subjects received a diet and partially defatted GBN 13 g per day (≈227.5 μg/day of selenium) or placebo for twelve weeks with four-week washout interval. Anthropometric, laboratory and clinic characteristics were investigated at baseline. Plasma selenium (Se), plasma glutathione peroxidase (GPx3) activity, total antioxidant capacity (TAC), 8-epi PGF2α and oxidized LDL were evaluated at the beginning and in the end of each intervention. GBN intake significantly increased plasma Se from 87.0 ± 16.8 to 180.6 ± 67.1 μg/L, increased GPx3 activity in 24,8% (from 112.66 ± 40.09 to 128.32 ± 38.31 nmol/min/mL, p < 0,05), and reduced 3.25% of oxidized-LDL levels (from 66.31 ± 23.59 to 60.68 ± 20.88 U/L, p < 0.05). An inverse association between GPx3 and oxidized LDL levels was observed after supplementation with GBN by simple model (β -0.232, p = 0.032) and after adjustment for gender, age, diabetes and BMI (β -0.298, p = 0.008). There wasn't association between GPx3 and 8-epi PGF2α (β -0.209, p = 0.052) by simple model. The partially defatted GBN intake has a potential benefit to increase plasma selenium, increase enzymatic antioxidant activity of GPx3 and to reduction oxidation in LDL in hypertensive and dyslipidemic patients. ClinicalTrials.gov Identifier NCT01990391; November 20, 2013.

Erythrocyte selenium concentration predicts intensive care unit and hospital mortality in patients with septic shock: a prospective observational study

PubMed Central

2014-01-01

Introduction Selenoenzymes can modulate the extent of oxidative stress, which is recognized as a key feature of septic shock. The pathophysiologic role of erythrocyte selenium concentration in patients with septic shock remains unknown. Therefore, the objective of this study was to evaluate the association of erythrocyte selenium concentration with glutathione peroxidase (GPx1) activity, GPx1 polymorphisms and with ICU and hospital mortality in septic shock patients. Methods This prospective study included all patients older than 18 years with septic shock on admission or during their ICU stay, admitted to one of the three ICUs of our institution, from January to August 2012. At the time of the patients’ enrollment, demographic information was recorded. Blood samples were taken within the first 72 hours of the patients’ admission or within 72 hours of the septic shock diagnosis for determination of selenium status, protein carbonyl concentration, GPx1 activity and GPx1 Pro198Leu polymorphism (rs 1050450) genotyping. Results A total of 110 consecutive patients were evaluated. The mean age was 57.6 ± 15.9 years, 63.6% were male. Regarding selenium status, only erythrocyte selenium concentration was lower in patients who died in the ICU. The frequencies for GPx1 Pro198Leu polymorphism were 55%, 38% and 7% for Pro/Pro, Pro/Leu and Leu/Leu, respectively. In the logistic regression models, erythrocyte selenium concentration was associated with ICU and hospital mortality in patients with septic shock even after adjustment for protein carbonyl concentration and acute physiology and chronic health evaluation II score (APACHE II) or sequential organ failure assessment (SOFA). Conclusions Erythrocyte selenium concentration was a predictor of ICU and hospital mortality in patients with septic shock. However, this effect was not due to GPx1 activity or Pro198Leu polymorphism. PMID:24887198

The Hypolipidemic and Pleiotropic Effects of Rosuvastatin Are Not Enhanced by Its Association with Zinc and Selenium Supplementation in Coronary Artery Disease Patients: A Double Blind Randomized Controlled Study

PubMed Central

Sena-Evangelista, Karine Cavalcanti Maurício; Pedrosa, Lucia Fatima Campos; Paiva, Maria Sanali Moura Oliveira; Dias, Paula Cristina Silveira; Ferreira, Diana Quitéria Cabral; Cozzolino, Sílvia Maria Franciscato; Faulin, Tanize Espírito Santo; Abdalla, Dulcinéia Saes Parra

2015-01-01

Objective Statins treatment may modify the levels of zinc and selenium, minerals that can improve vascular function and reduce oxidative damage and inflammation in atherosclerotic patients. This study aimed to evaluate the effects of rosuvastatin, alone or associated with zinc and selenium supplementation, on lipid profile, antioxidant enzymes and mineral status in coronary artery disease patients. Material and Methods A double-blind randomized clinical trial was performed in which patients (n = 76) were treated with 10 mg rosuvastatin over 4 months associated or not with zinc (30 mg/d) and selenium (150 μg/d) supplementation. The following parameters were analyzed before and after the intervention: anthropometric measurements, lipid profile, high sensitivity C-reactive protein (hs-CRP), electronegative low density lipoprotein (LDL(-)) concentrations, activities of glutathione peroxidase (GPx), superoxide dismutase (SOD), zinc and selenium concentrations in blood plasma and erythocytes. Significance was determined using an α of 5% (two-tailed). Results We found that rosuvastatin therapy was efficient in reducing total cholesterol, LDL-cholesterol, non-HDL cholesterol, triglycerides, and hs-CRP independently of mineral supplementation. Neither treatment was associated with significant changes in LDL(-). Similarly, the antioxidant enzymes GPx and SOD activity were unchanged by treatments. Neither treatment was associated with significant differences in concentrations of zinc or selenium in blood plasma and erythocytes of studied groups. Conclusion Rosuvastatin treatment did not affect zinc and selenium levels in coronary artery disease patients. The zinc and selenium supplementation at doses used in this study did not change lipid profile or SOD and GPx activity in patients receiving rosuvastatin. Further studies should be focused on testing alternative doses and supplements in different populations to contribute for a consensus on the ideal choice of antioxidants to be used as possible complementary therapies in atherosclerotic patients. Trial Registration ClinicalTrials.gov NCT01547377 PMID:25785441

On the potential increase of the oxidative stress status in patients with abdominal aortic aneurysm.

PubMed

Pincemail, J; Defraigne, J O; Cheramy-Bien, J P; Dardenne, N; Donneau, A F; Albert, A; Labropoulos, N; Sakalihasan, N

2012-01-01

Abdominal aortic aneurysm (AAA) is a major cause of preventable deaths in older patients. Oxidative stress has been suggested to play a key role in the pathogenesis of AAA. However, only few studies have been conducted to evaluate the blood oxidative stress status of AAA patients. Twenty seven AAA patients (mean age of 70 years) divided into two groups according to AAA size (≤ 50 or > 50 mm) were compared with an age-matched group of 18 healthy subjects. Antioxidants (vitamins C and E, β-carotene, glutathione, thiols, and ubiquinone), trace elements (selenium, copper, zinc, and copper/zinc ratio) and markers of oxidative damage to lipids (lipid peroxides, antibodies against oxidized patients, and isoprostanes) were measured in each subject. The comparison of the three groups by ordinal logistic regression showed a significant decrease of the plasma levels of vitamin C (P = 0.011), α-tocopherol (P = 0.016) but not when corrected for cholesterol values, β-carotene (P = 0.0096), ubiquinone (P = 0.014), zinc (P = 0.0035), and of selenium (P = 0.0038), as AAA size increased. By contrast, specific markers of lipid peroxidation such as the Cu/Zn ratio (P = 0.046) and to a lesser extent isoprostanes (P = 0.052) increased. The present study emphasizes the potential role of the oxidative stress in AAA disease and suggests that an antioxidant therapy could be of interest to delay AAA progression.

Selenium concentrations and enzyme activities of glutathione metabolism in wild long-tailed ducks and common eiders

USGS Publications Warehouse

Franson, J. Christian; Hoffman, David J.; Flint, Paul L.

2011-01-01

The relationships of selenium (Se) concentrations in whole blood with plasma activities of total glutathione peroxidase, Se-dependent glutathione peroxidase, and glutathione reductase were studied in long-tailed ducks (Clangula hyemalis) and common eiders (Somateria mollissima) sampled along the Beaufort Sea coast of Alaska, USA. Blood Se concentrations were >8 μg/g wet weight in both species. Linear regression revealed that the activities of total and Se-dependent glutathione peroxidase were significantly related to Se concentrations only in long-tailed ducks, raising the possibility that these birds were experiencing early oxidative stress.

Large-area synthesis of WSe2 from WO3 by selenium-oxygen ion exchange

NASA Astrophysics Data System (ADS)

Browning, Paul; Eichfeld, Sarah; Zhang, Kehao; Hossain, Lorraine; Lin, Yu-Chuan; Wang, Ke; Lu, Ning; Waite, A. R.; Voevodin, A. A.; Kim, Moon; Robinson, Joshua A.

2015-03-01

Few-layer tungsten diselenide (WSe2) is attractive as a next-generation electronic material as it exhibits modest carrier mobilities and energy band gap in the visible spectra, making it appealing for photovoltaic and low-powered electronic applications. Here we demonstrate the scalable synthesis of large-area, few-layer WSe2 via replacement of oxygen in hexagonally stabilized tungsten oxide films using dimethyl selenium. Cross-sectional transmission electron microscopy reveals successful control of the final WSe2 film thickness through control of initial tungsten oxide thickness, as well as development of layered films with grain sizes up to several hundred nanometers. Raman spectroscopy and atomic force microscopy confirms high crystal uniformity of the converted WSe2, and time domain thermo-reflectance provide evidence that near record low thermal conductivity is achievable in ultra-thin WSe2 using this method.

Effect of ubiquinone Q(10) and antioxidant vitamins on free radical oxidation of phospholipids in biological membranes of rat liver.

PubMed

Tikhaze, A K; Konovalova, G G; Lankin, V Z; Kaminnyi, A I; Kaminnaja, V I; Ruuge, E K; Kukharchuk, V V

2005-08-01

We studied the effects of 30-day peroral treatment with beta-carotene, a complex of antioxidant vitamins (vitamins C and E and provitamin A) and selenium, and solubilized ubiquinone Q(10) on the antioxidant potential in rat liver (ascorbate-dependent free radical oxidation of unsaturated membrane phospholipids). beta-Carotene irrespective of the administration route increased antioxidant potential of the liver by 2-3.5 times. The complex of antioxidant vitamins and selenium increased this parameter by more than 15 times. Antiradical activity in rat liver was extremely high after administration of solubilized ubiquinone Q(10) (increase by more than by 36 times). It can be expected that reduced ubiquinone Q(10) in vivo should produce a more pronounced protective effect due to activity of the system for bioregeneration of this natural antioxidant.

The Importance of Antioxidant Micronutrients in Pregnancy

PubMed Central

Mistry, Hiten D.; Williams, Paula J.

2011-01-01

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. PMID:21918714

Selenium adsorption to aluminum-based water treatment residuals

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ippolito, James A.; Scheckel, Kirk G.; Barbarick, Ken A.

2009-09-02

Aluminum-based water treatment residuals (WTR) can adsorb water- and soil-borne P, As(V), As(III), and perchlorate, and may be able to adsorb excess environmental selenium. WTR, clay minerals, and amorphous aluminum hydroxide were shaken for 24 h in selenate or selenite solutions at pH values of 5-9, and then analyzed for selenium content. Selenate and selenite adsorption edges were unaffected across the pH range studied. Selenate adsorbed on to WTR, reference mineral phases, and amorphous aluminum hydroxide occurred as outer sphere complexes (relatively loosely bound), while selenite adsorption was identified as inner-sphere complexation (relatively tightly bound). Selenite sorption to WTR inmore » an anoxic environment reduced Se(IV) to Se(0), and oxidation of Se(0) or Se(IV) appeared irreversible once sorbed to WTR. Al-based WTR could play a favorable role in sequestering excess Se in affected water sources.« less

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

PubMed

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.

In vitro antioxidant and antiproliferative activities of selenium-containing phycocyanin from selenium-enriched Spirulina platensis.

PubMed

Chen, Tianfeng; Wong, Yum-Shing

2008-06-25

Both selenium and phycocyanin have been reported to show potent cancer chemopreventive activities. In this study, we investigated the in vitro antioxidant and antiproliferative activities of selenium-containing phycocyanin (Se-PC) purified from selenium-enriched Spirulina platensis. The antioxidant activity of Se-PC was evaluated by using four different free radical scavenging assays, namely, the 2,2'-azinobis-3-ethylbenzothiazolin-6-sulfonic acid (ABTS) assay, 1,1-diphenyl-2-picryhydrazyl (DPPH) assay, superoxide anion scavenging assay, and erythrocyte hemolysis assay. The results indicated that Se-PC exhibited stronger antioxidant activity than phycocyanin by scavenging ABTS, DPPH, superoxide anion, and 2,2'-azobis-(2-amidinopropane)dihydrochloride free radicals. Se-PC also showed dose-dependent protective effects on erythrocytes against H 2O 2-induced oxidative DNA damage as evaluated by the Comet assay. Moreover, Se-PC was identified as a potent antiproliferative agent against human melanoma A375 cells and human breast adenocarcinoma MCF-7 cells. Induction of apoptosis in both A375 and MCF-7 cells by Se-PC was evidenced by accumulation of sub-G1 cell populations, DNA fragmentation, and nuclear condensation. Further investigation on intracellular mechanisms indicated that depletion of mitochondrial membrane potential (DeltaPsi m) was involved in Se-PC-induced cell apoptosis. Our findings suggest that Se-PC is a promising organic Se species with potential applications in cancer chemoprevention.

Marine redox structure at the culmination of the Great Oxidation Event: Insights from the Zaonega Formation, Karelia, Russia

NASA Astrophysics Data System (ADS)

Kipp, M.; Lepland, A.; Buick, R.

2017-12-01

The availability of dissolved oxygen is thought to have been the dominant throttle on the evolution and diversification of eukaryotic life during the Proterozoic Eon [1]. In the mid-Proterozoic, during the interval that presaged the rise of eukaryotes to ecological dominance, oxygen scarcity is thought to have relegated eukaryotic organisms to slivers of oxygenated shallow oceans [2]. However, recent work has suggested that oxygen levels rose dramatically during the early Paleoproterozoic Great Oxidation Event before crashing to the low levels of the mid-Proterozoic [3]. Evidence from selenium isotopes in shales [4] and iodate concentrations in carbonates [5] has even suggested that wide swathes of continental shelves were oxic enough to support eukaryotic organisms at this time. How oxic though, and for how long, remain poorly constrained. Here we present new selenium geochemical data from the Zaonega Formation of Karelia, Russia that can help resolve those questions. Previous work has proposed that the Zaonega Formation, and correlative Francevillian Series of Gabon, record the establishment of an oxygen-rich atmosphere at the culmination of the GOE [6]. Our selenium isotope dataset provides a test for this hypothesis, and can also be used to assess the preservation of the geochemical signatures in the Zaonega Formation. These data point to regional redox fluctuations, but due to the short marine residence time of selenium, extrapolating these results to global phenomena remains difficult. 1. Reinhard, et al (2016) PNAS 2. Planavsky, et al (2014) Science 3. Bekker and Holland (2012) EPSL 4. Kipp, et al (2017) PNAS 5. Hardisty, et al (2014) Geology 6. Kump, et al (2011) Science

Selenium and vitamin E together improve intestinal epithelial barrier function and alleviate oxidative stress in heat-stressed pigs.

PubMed

Liu, Fan; Cottrell, Jeremy J; Furness, John B; Rivera, Leni R; Kelly, Fletcher W; Wijesiriwardana, Udani; Pustovit, Ruslan V; Fothergill, Linda J; Bravo, David M; Celi, Pietro; Leury, Brian J; Gabler, Nicholas K; Dunshea, Frank R

2016-07-01

What is the central question of this study? Oxidative stress may play a role in compromising intestinal epithelial barrier integrity in pigs subjected to heat stress, but it is unknown whether an increase of dietary antioxidants (selenium and vitamin E) could alleviate gut leakiness in heat-stressed pigs. What is the main finding and its importance? Levels of dietary selenium (1.0 p.p.m.) and vitamin E (200 IU kg(-1) ) greater than those usually recommended for pigs reduced intestinal leakiness caused by heat stress. This finding suggests that oxidative stress plays a role in compromising intestinal epithelial barrier integrity in heat-stressed pigs and also provides a nutritional strategy for mitigating these effects. Heat stress compromises the intestinal epithelial barrier integrity of mammals through mechanisms that may include oxidative stress. Our objective was to test whether dietary supplementation with antioxidants, selenium (Se) and vitamin E (VE), protects intestinal epithelial barrier integrity in heat-stressed pigs. Female growing pigs (n = 48) were randomly assigned to four diets containing from 0.2 p.p.m. Se and 17 IU kg(-1) VE (control, National Research Council recommended) to 1.0 p.p.m. Se and 200 IU kg(-1) VE for 14 days. Six pigs from each dietary treatment were then exposed to either thermoneutral (20°C) or heat-stress conditions (35°C 09.00-17.00 h and 28°C overnight) for 2 days. Transepithelial electrical resistance and fluorescein isothiocyanate-dextran (4 kDa; FD4) permeability were measured in isolated jejunum and ileum using Ussing chambers. Rectal temperature, respiratory rate and intestinal HSP70 mRNA abundance increased (all P < 0.001), and respiratory alkalosis occurred, suggesting that pigs were heat stressed. Heat stress also increased FD4 permeability and decreased transepithelial electrical resistance (both P < 0.01). These changes were associated with changes indicative of oxidative stress, a decreased glutathione peroxidase (GPX) activity and an increased glutathione disulfide (GSSG)-to-glutathione (GSH) ratio (both P < 0.05). With increasing dosage of Se and VE, GPX-2 mRNA (P = 0.003) and GPX activity (P = 0.049) increased linearly, the GSSG:GSH ratio decreased linearly (P = 0.037), and the impacts of heat stress on intestinal barrier function were reduced (P < 0.05 for both transepithelial electrical resistance and FD4 permeability). In conclusion, in pigs an increase of dietary Se and VE mitigated the impacts of heat stress on intestinal barrier integrity, associated with a reduction in oxidative stress. © 2016 The Authors. Experimental Physiology © 2016 The Physiological Society.

Chemical Form and Distribution of Selenium and Sulfur in the Selenium Hyperaccumulator Astragalus bisulcatus1

PubMed Central

Pickering, Ingrid J.; Wright, Carrie; Bubner, Ben; Ellis, Danielle; Persans, Michael W.; Yu, Eileen Y.; George, Graham N.; Prince, Roger C.; Salt, David E.

2003-01-01

In its natural habitat, Astragalus bisulcatus can accumulate up to 0.65% (w/w) selenium (Se) in its shoot dry weight. X-ray absorption spectroscopy has been used to examine the selenium biochemistry of A. bisulcatus. High concentrations of the nonprotein amino acid Se-methylseleno-cysteine (Cys) are present in young leaves of A. bisulcatus, but in more mature leaves, the Se-methylseleno-Cys concentration is lower, and selenate predominates. Seleno-Cys methyltransferase is the enzyme responsible for the biosynthesis of Se-methylseleno-Cys from seleno-Cys and S-methyl-methionine. Seleno-Cys methyltransferase is found to be expressed in A. bisulcatus leaves of all ages, and thus the biosynthesis of Se-methylseleno-Cys in older leaves is limited earlier in the metabolic pathway, probably by an inability to chemically reduce selenate. A comparative study of sulfur (S) and Se in A. bisulcatus using x-ray absorption spectroscopy indicates similar trends for oxidized and reduced Se and S species, but also indicates that the proportions of these differ significantly. These results also indicate that sulfate and selenate reduction are developmentally correlated, and they suggest important differences between S and Se biochemistries. PMID:12644695

Microbial oxidation and solubilization of precipitated elemental selenium in soil

DOE Office of Scientific and Technical Information (OSTI.GOV)

Losi, M.E.; Frankenberger, W.T. Jr.

1998-07-01

Oxidation of elemental selenium (Se{sup 0}) leads to increased solubilization and enhanced bioavailability. In this work, laboratory microcosm experiments were conducted to study oxidation of Se{sup 0} in soil and liquid cultures. Major objectives were to examine the oxidation rates of four San Joaquin Valley, California soils, and to assess the contribution of biological vs. chemical processes. For these experiments, red, crystalline Se{sup 0} was prepared by both chemical and biological synthesis, and its presence was confirmed by synchrotron-based x-ray absorption spectroscopy. The amount of Se{sup 0} oxidized over 125 d was from 1 to 10% of Se{sup 0} inmore » soils spiked to 250 mg Se{sup 0} kg{sup {minus}1} and approximately half that in soils spiked to 100 mg Se{sup 0} kg{sup {minus}1}. First order rate constants for oxidation of Se{sup 0} were from 0.05 to 0.32 yr{sup {minus}1} and 0.04 to 0.39 yr{sup {minus}1} at 250 and 100 mg Se{sup 0} kg{sup {minus}1} soil, respectively. The amount of Se{sup 0} oxidized was generally correlated with prior exposure of the soil to Se. Products included either selenite (SeO{sub 3}{sup 2{minus}}), or both (SeO{sub 3}{sup 2{minus}}) and selenate (SeO{sub 4}{sup 2{minus}}). Biotic processes were shown to be of major importance. Both heterotrophic and autotrophic oxidation were observed, and an inorganic C source (NaHCO{sub 3}) was favored relative to glucose. This study demonstrates that Se{sup 0} oxidation in soils is largely biotic in nature, occurs at relatively slow rates and yields both SeO{sub 3}{sup 2{minus}} and SeO{sub 4}{sup 2{minus}}.« less

Synergy between sulforaphane and selenium in the up-regulation of thioredoxin reductase and protection against hydrogen peroxide-induced cell death in human hepatocytes.

PubMed

Li, Dan; Wang, Wei; Shan, Yujuan; Barrera, Lawrence N; Howie, Alexander F; Beckett, Geoffrey J; Wu, Kun; Bao, Yongping

2012-07-15

Dietary isothiocyanates and selenium are chemopreventive agents and potent inducers of antioxidant enzymes. It has been previously shown that sulforaphane and selenium have a synergistic effect on the upregulation of thioredoxin reductase-1 (TrxR-1) in human hepatoma HepG2 cells. In this paper, further evidence is presented to show that sulforaphane and selenium synergistically induce TrxR-1 expression in immortalised human hepatocytes. Sulforaphane was found to be more toxic toward hepatocytes than HepG2 cells with IC50=25.1 and 56.4 μM, respectively. Sulforaphane can protect against hydrogen peroxide-induced cell death and this protection was enhanced by co-treatment with selenium. Using siRNA to knock down TrxR-1 or Nrf2, sulforaphane (5 μM)-protected cell viability was reduced from 73% to 46% and 34%, respectively, suggesting that TrxR-1 is an important enzyme in protection against hydrogen peroxide-induced cell death. Sulforaphane-induced TrxR-1 expression was positively associated with significant levels of Nrf2 translocation into the nucleus, but co-treatment with selenium showed no significant increase in Nrf2 translocation. Moreover, MAPK (ERK, JNK and p38) and PI3K/Akt signalling pathways were found to play no significant role in sulforaphane-induced Nrf2 translocation into the nucleus. However, blocking ERK and JNK signalling pathways decreased sulforaphane-induced TrxR-1 mRNA by about 20%; whereas blocking p38 and PI3K/AKT increased TrxR-1 transcription. In summary, a combination of sulforaphane and selenium resulted in a synergistic upregulation of TrxR-1 that contributed to the enhanced protection against free radical-mediated oxidative damage in human hepatocytes. Copyright © 2012 Elsevier Ltd. All rights reserved.

Effects of selenium supplementation on the oxidative state of acute heat stress-exposed quails.

PubMed

Del Vesco, A P; Gasparino, E; Zancanela, V; Grieser, D O; Stanquevis, C E; Pozza, P C; Oliveira Neto, A R

2017-02-01

This study aimed to evaluate the effect of heat stress (HS) and selenium supplementation on markers of stress, meat quality and gene expression. For this, meat quails of 42 days of age were fed a diet that either met [0.33 mg/kg, nutritional demand for selenium (SS)] or did not meet [0.11 mg/kg, selenium deficient (SD)] the nutritional demands for selenium during the 7 days of evaluation. In addition, the animals were kept at either a thermal comfort temperature (25 °C) or exposed to HS (38 °C for 24 h). Glutathione synthetase (GSS), glutathione reductase (GSR) and uncoupling protein (UCP) gene expression were influenced by the interaction between temperature and diet. Animals subjected to HS and fed the SS diet exhibited the highest GSS and GSR gene expression. In terms of UCP gene expression, the lowest values were observed in HS animals on the SD diet. Glutathione peroxidase 7 (GPX7) gene expression, body temperature (BT) and creatine kinase (CK) activity were influenced by both selenium supplementation and HS. Aspartate aminotransferase (AST), alanine aminotransferase (ALT) activity and creatinine content all were influenced by the diet/environment interaction. The highest AST activity, ALT activity and creatinine levels were observed in animals that were both on the SD diet and exposed to HS. HS animals also exhibited an increased heterophil/lymphocyte ratio and lower triiodothyronine (T3) hormone levels than birds that remained at the comfortable temperature. Animals subjected to HS and fed with selenium supplemented diet showed better results regarding gene expression and, thus, better results for the activities of enzymes used as stress markers, which could be due to the higher antioxidant capacity provided by the action of the studied genes. Journal of Animal Physiology and Animal Nutrition © 2016 Blackwell Verlag GmbH.

Fractionation of selenium isotopes during bacterial respiratory reduction of selenium oxyanions

USGS Publications Warehouse

Herbel, M.J.; Johnson, T.M.; Oremland, R.S.; Bullen, T.D.

2000-01-01

Reduction of selenium oxyanions by microorganisms is an important process in the biogeochemical cycling of selenium. Numerous bacteria can reduce Se oxyanions, which are used as electron acceptors during the oxidation of organic matter in anoxic environments. In this study, we used a double spike (82Se and 74Se) thermal ionization mass spectrometry technique to quantify the isotopic fractionation achieved by three different species of anaerobic bacteria capable of accomplishing growth by respiratory reduction of selenate [SeO42- or Se(VI)] or selenite [SeO32- or Se(IV)] to Se(IV) or elemental selenium [Se(0)] coupled with the oxidation of lactate. Isotopic discrimination in these closed system experiments was evaluated by Rayleigh fractionation equations and numerical models. Growing cultures of Bacillus selenitireducens, a haloalkaliphile capable of growth using Se(IV) as an electron acceptor, induced a 80Se/76Se fractionation of -8.0 ?? 0.4??? (instantaneous ?? value) during reduction of Se(IV) to Se(0). With Bacillus arsenicoselenatis, a haloalkaliphile capable of growth using Se(VI) as an electron acceptor, fractionations of -5.0 ?? 0.5??? and -6.0 ?? 1.0??? were observed for reduction of Se(VI) to Se(IV) and reduction of Se(IV) to Se(0), respectively. In growing cultures of Sulfurospirillum barnesii, a freshwater species capable of growth using Se(VI), fractionation was small initially, but near the end of the log growth phase, it increased to -4.0 ?? 1.0??? and -8.4 ?? 0.4??? for reduction of Se(VI) to Se(IV) and reduction of Se(IV) to Se(O), respectively. Washed cell suspensions of S. barnesii induced fractionations of -1.1 ?? 0.4??? during Se(VI) reduction, and -9.1 ?? 0.5% for Se(IV) reduction, with some evidence for smaller values (e.g., -1.7???) in the earliest-formed Se(0) results. These results demonstrate that dissimilatory reduction of selenate or selenite induces significant isotopic fractionation, and suggest that significant Se isotope ratio variation will be found in nature. Copyright (C) 2000 Elsevier Science Ltd.

Temporal variations in dissolved selenium in Lake Kinneret (Israel)

USGS Publications Warehouse

Nishri, A.; Brenner, I.B.; Hall, G.E.M.; Taylor, Howard E.

1999-01-01

Selenium is an essential micronutrient for the growth of the dinoflagellate Peridinium gatunense that dominates the spring algal bloom in Lake Kinneret (LK). The relationship between the levels of dissolved selenium species and the occurance of algal blooms in this lake was studied. During algal blooms of P. gatunense in spring and of the blue-green Aphanizomenon ovalisporum in fall (in 1994) the concentration of epilimnetic dissolved organic Se (Se(org)) increased whereas that of selenite (SeIV) decreased, to levels below the limit of detection: 5 ng/l. The disappearance of SeIV during these blooms is attributed to algal uptake and it is suggested that the growth of both algae may have depended on Se(org) regeneration. A budget performed for selenate (SeVI) suggests that this species is also consumed by algae but to a lesser extent than SeIV (in 1994 ~40% of the epilimnetic load). During the stratification period the hypolimnion of Lake Kinneret becomes anoxic, with high levels of dissolved sulfide. The affects of this environment on the distribution of Se oxy-anions, selenite (SeIV) and selenate(SeVI), were also studied. At the onset of thermal stratification (March) about 35% of the lake inventory of both Se oxidized species are entrapped in the hypolimnion. During stages of oxygen depletion and H2S accumulation, SeIV is completely and SeVI partially removed from this layer. The removal is attributed to reduction followed by formation of particulate reduced products, such as elemental selenium Se(o). The ratio between SeVI to total dissolved selenium (SE(T)) in water sources to the lake is ~0.84, about twice the corresponding ratio in the lake (~0.44, during holomixis). In the lake about 75% of annual SeVI inflow from external sources undergoes reduction to selenide (Se-II) and Se(o) through epilimnetic algal assimilation and hypolimnetic anoxic reduction, respectively. It is suggested that the latter oxidation of the dissolved organic selenide released from biogenic particles and of Se(o) only to the tetravalent species is the cause for the lower ratio of SeVI/Se(T) in the lake.

GPX1 Pro198Leu polymorphism and GSTM1 deletion do not affect selenium and mercury status in mildly exposed Amazonian women in an urban population.

PubMed

Rocha, Ariana V; Rita Cardoso, Bárbara; Zavarize, Bruna; Almondes, Kaluce; Bordon, Isabella; Hare, Dominic J; Teixeira Favaro, Déborah Inês; Franciscato Cozzolino, Silvia Maria

2016-11-15

Mercury is potent toxicant element, but its toxicity can be reduced by forming a complex with selenium for safe excretion. Considering the impact of mercury exposure in the Amazon region and the possible interaction between these two elements, we aimed to assess the effects of Pro198Leu polymorphism to GPX1 and GSTM1 deletion, on mercury levels in a population from Porto Velho, an urban locality in the Brazilian Amazon region. Two hundred women from the capital city of Rondônia state were recruited for this study with 149 deemed suitable to participate. We assessed dietary intake using 24-hour recall. Selenium levels in plasma and erythrocytes were measured using hydride generation quartz tube atomic absorption spectroscopy and total hair mercury using cold vapor atomic absorption spectrometry. Oxidative stress parameters (GPx activity, oxygen radical absorbency capacity [ORAC] and malondialdehyde [MDA]) were also analyzed. All participants were genotyped for Pro198Leu polymorphism and GSTM1 deletion. We observed that this population presented high prevalence of selenium deficiency, and also low levels of mercury, likely due to food habits that did not include selenium-rich food sources or significant consumption of fish (mercury biomagnifiers) regularly. Univariate statistical analysis showed that Pro198Leu and GSTM1 genotypes did not affect selenium and mercury levels in this population. Pro198Leu polymorphism and GSTM1 deletion had no effect on mercury levels in mildly exposed people, suggesting these genetic variants impact mercury levels only in highly exposed populations. Copyright © 2016 Elsevier B.V. All rights reserved.

Reducing arsenic accumulation in rice grain through iron oxide amendment

USDA-ARS?s Scientific Manuscript database

In this research, we investigated the accumulation of arsenic (As), selenium (Se), molybdenum (Mo), and cadmium (Cd) in rice grain under different soil conditions in standard straighthead-resistant and straighthead-susceptible cultivars, Zhe 733 and Cocodrie, respectively. Results demonstrated that,...

The Level of Selenium and Oxidative Stress in Workers Chronically Exposed to Lead.

PubMed

Pawlas, Natalia; Dobrakowski, Michał; Kasperczyk, Aleksandra; Kozłowska, Agnieszka; Mikołajczyk, Agnieszka; Kasperczyk, Sławomir

2016-03-01

The possible beneficial role of selenium (Se) on the oxidative stress induced by lead (Pb) is still unclear in humans. Therefore, the aim of the present study was to explore the associations among the Se levels, chronic Pb exposure, oxidative stress parameters, and parameters characterizing the function of the antioxidant defense system in men who are occupationally exposed to Pb. Based on the median serum Se concentrations, the 324 study subjects were divided into two subgroups: a subgroup with a low Se level (L-Se) and a subgroup with a high Se level (H-Se). The levels of lead (PbB) and zinc protoporphyrin (ZPP) in the blood and the delta-aminolevulinic acid (ALA) level in the urine served as indices of Pb exposure. The PbB level was significantly lower in the H-Se group compared to that in the L-Se group by 6 %. The levels of 8-hydroxyguanosine and lipofuscin (LPS) and the activity of superoxide dismutase were significantly lower in the H-Se group compared to that in the L-Se group by 17, 19, and 11 %, respectively. However, the glutathione level (GSH) and the activities of glutathione peroxidase (GPx) and catalase were significantly higher by 9, 23, and 3 %. Spearman correlations showed positive associations between the Se level and GPx activity and GSH level. A lower serum Se level in chronically Pb-exposed subjects is associated with higher Pb blood levels and an elevated erythrocyte LPS level, which reflects the intensity of oxidative stress. Besides, in a group of Pb-exposed subjects with lower serum Se level, depleted GSH pool and decreased activity of GPx in erythrocytes were reported. However, the present results are inadequate to recommend Se supplementation for chronic lead exposure at higher doses than would be included in a normal diet except for selenium deficiency.

Redox reactions of selenium as catalyzed by magnetite: Lessons learned from using electrochemistry and spectroscopic methods

NASA Astrophysics Data System (ADS)

Kim, YoungJae; Yuan, Ke; Ellis, Brian R.; Becker, Udo

2017-02-01

Although previous studies have demonstrated redox transformations of selenium (Se) in the presence of Fe-bearing minerals, the specific mechanism of magnetite-mediated Se electron transfer reactions are poorly understood. In this study, the redox chemistry of Se on magnetite is investigated over an environmentally relevant range of Eh and pH conditions (+0.85 to -1.0 V vs. Ag/AgCl; pH 4.0-9.5). Se redox peaks are found via cyclic voltammetry (CV) experiments at pH conditions of 4.0-8.0. A broad reduction peak centered at -0.5 V represents a multi-electron transfer process involving the transformation of selenite to Se(0) and Se(-II) and the comproportionation reaction between Se(-II) and Se(IV). Upon anodic scans, the oxidation peak centered at -0.25 V is observed and is attributed to the oxidation of Se(-II) to higher oxidation states. Deposited Se(0) may be oxidized at +0.2 V when pH is below 7.0. Over a pH range of 4.0-8.0, the pH dependence of peak potentials is less pronounced than predicted from equilibrium redox potentials. This is attributed to pH gradients in the microporous media of the cavity where the rate of proton consumption by the selenite reduction is faster relative to mass transfer from the solution. In chronoamperometry measurements at potentials ⩾-0.6 V, the current-time transients show good linearity between the current and time in a log-log scale. In contrast, deviation from the linear trend is observed at more negative potentials. Such a trend is indicative of Se(0) nucleation and growth on the magnetite surface, which can be theoretically explained by the progressive nucleation model. XPS analysis reveals the dominance of elemental selenium at potentials ⩽-0.5 V, in good agreement with the peak assignment on the cyclic voltammograms and the nucleation kinetic results.

Mechanisms of inhibition of zinc-finger transcription factors by selenium compounds ebselen and selenite.

PubMed

Larabee, Jason L; Hocker, James R; Hanas, Jay S

2009-03-01

The anti-inflammatory selenium compounds, ebselen (2-phenyl-1,2-benzisoselenazol-3[2H]-one) and selenite, were found to alter the DNA binding mechanisms and structures of cysteine-rich zinc-finger transcription factors. As assayed by DNase I protection, DNA binding by TFIIIA (transcription factor IIIA, prototypical Cys(2)His(2) zinc finger protein), was inhibited by micromolar amounts of ebselen. In a gel shift assay, ebselen inhibited the Cys(2)His(2) zinc finger-containing DNA binding domain (DBD) of the NF-kappaB mediated transcription factor Sp1. Ebselen also inhibited DNA binding by the p50 subunit of the pro-inflammatory Cys-containing NF-kappaB transcription factor. Electrospray ionization mass spectrometry (ESI-MS) was utilized to elucidate mechanisms of chemical interaction between ebselen and a zinc-bound Cys(2)His(2) zinc finger polypeptide modeled after the third finger of Sp1 (Sp1-3). Exposing Sp1-3 to micromolar amounts of ebselen resulted in Zn(2+) release from this peptide and the formation of a disulfide bond by oxidation of zinc finger SH groups, the likely mechanism for DNA binding inhibition. Selenite was shown by ESI-MS to also eject zinc from Sp1-3 as well as induce disulfide bond formation through SH oxidation. The selenite-dependent inhibition/oxidation mechanism differed from that of ebselen by inducing the formation of a stable selenotrisulfide bond. Selenite-induced selenotrisulfide formation was dependent upon the structure of the Cys(2)His(2) zinc finger as alteration in the finger structure enhanced this reaction as well as selenite-dependent zinc release. Ebselen and selenite-dependent inhibition/oxidation of Cys-rich zinc finger proteins, with concomitant release of zinc and finger structural changes, points to mechanisms at the atomic and protein level for selenium-induced alterations in Cys-rich proteins, and possible amelioration of certain inflammatory, neurodegenerative, and oncogenic responses.

The effects of heavy metal ions, phthalates and ochratoxin A on oxidation of carcinogenic aristolochic acid I causing Balkan endemic nephropathy.

PubMed

Barta, Frantisek; Levova, Katerina; Hodek, Petr; Schmeiser, Heinz H; Arlt, Volker M; Stiborova, Marie

2015-01-01

Balkan endemic nephropathy (BEN) is a chronic progressive fibrosis associated with upper urothelial carcinoma (UUC). Aetiology of BEN is still not fully explained. Although carcinogenic aristolochic acid I (AAI) was proven as the major cause of BEN/UUC, this nephropathy is considered to be multifactorial. Hence, we investigated whether other factors considered as potential causes of BEN [a mycotoxin ochratoxin A (OTA), Cd, Pb, Se and As ions and organic compounds (i.e. phthalates) released from lignite deposits in BEN areas] can influence detoxication of AAI, whose concentrations are crucial for BEN development. Oxidation of AAI to 8-hydroxyaristolochic acid I (AAIa) in the presence of Cd, Pb, Se, As ions, dibutylphthalate (DBP), butylbenzylphthalate (BBP), bis(2-ethylhexyl)phthalate (DEHP) and OTA by rat liver microsomes was determined by HPLC. Only OTA, cadmium and selenium ions, and BBP inhibited AAI oxidation by rat liver microsomes. These compounds also inhibited activities of CYP1A1 and/or CYP2C6/11 catalysing AAI demethylation in rat livers. Therefore, these CYP inhibitions can be responsible for a decrease in AAIa formation. When the combined effects of these compounds were investigated, the most efficient inhibition was caused by OTA combined with BBP and selenium ions. The results show low effects of BBP, cadmium and selenium ions, and/or their combinations on AAI detoxication. No effects were produced by the other metal ions (Pb, As) and phthalates DBP and DEHP. This finding suggests that they do not influence AAI-mediated BEN development. In contrast, OTA might influence this process, by inhibition of AAI detoxication.

Distribution and reuse of {sup 76}Se-selenosugar in selenium-deficient rats

DOE Office of Scientific and Technical Information (OSTI.GOV)

Suzuki, Kazuo T.; Somekawa, Layla; Suzuki, Noriyuki

2006-10-15

Nutritional selenium compounds are transformed to the common intermediate selenide and then utilized for selenoprotein synthesis or excreted in urine mostly as 1{beta}-methylseleno-N-acetyl-DD-galactosamine (selenosugar). Since the biological significance of selenosugar formation is unknown, we investigated their role in the formation of selenoenzymes in selenium deficiency. Rats were depleted of endogenous natural abundance selenium with a single stable isotope ({sup 82}Se) and then made Se-deficient. {sup 76}Se-Selenosugar was administered intravenously to the rats and their urine, serum, liver, kidneys and testes were subjected to speciation analysis with HPLC inductively coupled argon plasma mass spectrometry. Most {sup 76}Se was recovered in itsmore » intact form (approximately 80% of dose) in urine within 1 h. Speciation analysis revealed that residual endogenous natural abundance selenium estimated by {sup 77}Se and {sup 78}Se was negligible and distinct distributions of the labeled {sup 76}Se were detected in the body fluids and organs without interference from the endogenous natural abundance stable isotope. Namely, intact {sup 76}Se-selenosugar was distributed to organs after the injection, and {sup 76}Se was used for selenoprotein synthesis. Oxidation to methylseleninic acid and/or hydrolysis of the selenoacetal group to methylselenol were proposed to the transformation of selenosugar for the reuse. Effective use of an enriched stable isotope as an absolute label in hosts depleted of natural abundance isotopes was discussed for application in tracer experiments.« less

The interactive effects of mercury and selenium on metabolic profiles, gene expression and antioxidant enzymes in halophyte Suaeda salsa.

PubMed

Liu, Xiaoli; Lai, Yongkai; Sun, Hushan; Wang, Yiyan; Zou, Ning

2016-04-01

Suaeda salsa is the pioneer halophyte in the Yellow River Delta and was consumed as a popular vegetable. Mercury has become a highly risky contaminant in the sediment of intertidal zones of the Yellow River Delta. In this work, we investigated the interactive effects of mercury and selenium in S. salsa on the basis of metabolic profiling, antioxidant enzyme activities and gene expression quantification. Our results showed that mercury exposure (20 μg L(-1)) inhibited plant growth of S. salsa and induced significant metabolic responses and altered expression levels of INPS, CMO, and MDH in S. salsa samples, together with the increased activities of antioxidant enzymes including SOD and POD. Overall, these results indicated osmotic and oxidative stresses, disturbed protein degradation and energy metabolism change in S. salsa after mercury exposures. Additionally, the addition of selenium could induce both antagonistic and synergistic effects including alleviating protein degradation and aggravating osmotic stress caused by mercury. © 2014 Wiley Periodicals, Inc.

Ultrathin inorganic molecular nanowire based on polyoxometalates

PubMed Central

Zhang, Zhenxin; Murayama, Toru; Sadakane, Masahiro; Ariga, Hiroko; Yasuda, Nobuhiro; Sakaguchi, Norihito; Asakura, Kiyotaka; Ueda, Wataru

2015-01-01

The development of metal oxide-based molecular wires is important for fundamental research and potential practical applications. However, examples of these materials are rare. Here we report an all-inorganic transition metal oxide molecular wire prepared by disassembly of larger crystals. The wires are comprised of molybdenum(VI) with either tellurium(IV) or selenium(IV): {(NH4)2[XMo6O21]}n (X=tellurium(IV) or selenium(IV)). The ultrathin molecular nanowires with widths of 1.2 nm grow to micrometre-scale crystals and are characterized by single-crystal X-ray analysis, Rietveld analysis, scanning electron microscopy, X-ray photoelectron spectroscopy, ultraviolet–visible spectroscopy, thermal analysis and elemental analysis. The crystals can be disassembled into individual molecular wires through cation exchange and subsequent ultrasound treatment, as visualized by atomic force microscopy and transmission electron microscopy. The ultrathin molecular wire-based material exhibits high activity as an acid catalyst, and the band gap of the molecular wire-based crystal is tunable by heat treatment. PMID:26139011

40 CFR 142.62 - Variances and exemptions from the maximum contaminant levels for organic and inorganic chemicals.

Code of Federal Regulations, 2014 CFR

2014-07-01

... Aeration 2 Granular Activated Carbon 3 Oxidation (Chlorination or Ozonation) (b) The Administrator... 1,2,5,6,7 Cadmium 2,5,6,7 Chromium 2,5,6 2,7 Cyanide 5,7,10 Mercury 2 1,4,6 1,7 1 Nickel 5,6,7.../1. 2 BAT for Chromium III only. 3 BAT for Selenium IV only. 4 BATs for Arsenic V. Pre-oxidation may...

40 CFR 142.62 - Variances and exemptions from the maximum contaminant levels for organic and inorganic chemicals.

Code of Federal Regulations, 2013 CFR

2013-07-01

... Aeration 2 Granular Activated Carbon 3 Oxidation (Chlorination or Ozonation) (b) The Administrator... 1,2,5,6,7 Cadmium 2,5,6,7 Chromium 2,5,6 2,7 Cyanide 5,7,10 Mercury 2 1,4,6 1,7 1 Nickel 5,6,7.../1. 2 BAT for Chromium III only. 3 BAT for Selenium IV only. 4 BATs for Arsenic V. Pre-oxidation may...

Effect of dietary α-tocopherol + ascorbic acid, selenium, and iron on oxidative stress in sub-yearling Chinook salmon (Oncorhynchus tshawytscha Walbaum)

USGS Publications Warehouse

Welker, T.L.; Congleton, J.L.

2009-01-01

A three-variable central composite design coupled with surface-response analysis was used to examine the effects of dietary ??-tocopherol + ascorbic acid (TOCAA), selenium (Se), and iron (Fe) on indices of oxidative stress in juvenile spring Chinook salmon. Each dietary factor was tested at five levels for a total of fifteen dietary combinations (diets). Oxidative damage in liver and kidney (lipid peroxidation, protein carbonyls) and erythrocytes (erythrocyte resistance to peroxidative lysis, ERPL) was determined after feeding experimental diets for 16 (early December) and 28 (early March) weeks. Only TOCAA influenced oxidative stress in this study, with most measures of oxidative damage decreasing (liver lipid peroxidation in December and March; ERPL in December; liver protein carbonyl in March) with increasing levels of TOCAA. We also observed a TOCAA-stimulated increase in susceptibility of erythrocytes to peroxidative lysis in March at the highest levels of TOCAA. The data suggest that under most circumstances a progressive decrease in oxidative stress occurs as dietary TOCAA increases, but higher TOCAA concentrations can stimulate oxidative damage in some situations. Higher levels of TOCAA in the diet were required in March than in December to achieve comparable levels of protection against oxidative damage, which may have been due to physiological changes associated with the parr-smolt transformation. Erythrocytes appeared to be more sensitive to variation in dietary levels of TOCAA than liver and kidney tissues. Using the March ERPL assay results as a baseline, a TOCAA level of approximately 350-600 mg/kg diet would provide adequate protection against lipid peroxidation under most circumstances in juvenile Chinook salmon. ?? 2008 The Authors.

Antioxidant effects of selenium on lung injury in paraquat intoxicated rats

USGS Publications Warehouse

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.

Selenium in Graves Hyperthyroidism and Orbitopathy.

PubMed

Marinò, Michele; Menconi, Francesca; Rotondo Dottore, Giovanna; Leo, Marenza; Marcocci, Claudio

2018-06-20

To review the in vitro and in vivo studies supporting a role of selenium for the treatment of mild Graves orbitopathy. Review of the current literature on the role of selenium in the management of Graves orbitopathy. Graves orbitopathy (GO) is a disfiguring and disabling disorder usually observed in patients with Graves hyperthyroidism, and more rarely in patients with hypothyroid autoimmune thyroiditis or in the absence of overt thyroid dysfunction. Noninvasive treatments include intravenous glucocorticoids and orbital radiotherapy and are generally offered to patients with moderately severe GO. In contrast, patients with mild GO are generally treated only with local measures. Thus, the benefits of intravenous glucocorticoids in mild GO are limited and do not justify the risks that the treatment carries. However, a medical treatment for mild GO is heavily wanted, as a relevant proportion of patients have a significant decrease in their quality of life, and GO can progress into more severe forms. Because of the role of oxidative stress in the pathogenesis of GO, an antioxidant approach has been proposed and the antioxidant agent selenium has been shown to be effective for GO. Studies have shown that a 6-month course of sodium selenite can improve the course of mild GO and prevent deterioration when compared with placebo.

Field evidence of selenium bioreduction in a uranium-contaminated aquifer.

PubMed

Williams, Kenneth H; Wilkins, Michael J; N'Guessan, A Lucie; Arey, Bruce; Dodova, Elena; Dohnalkova, Alice; Holmes, Dawn; Lovley, Derek R; Long, Philip E

2013-06-01

Removal of selenium from groundwater was documented during injection of acetate into a uranium-contaminated aquifer near Rifle, Colorado (USA). Bioreduction of aqueous selenium to its elemental form (Se0) concentrated it within mineralized biofilms affixed to tubing used to circulate acetate-amended groundwater. Scanning and transmission electron microscopy revealed close association between Se0 precipitates and cell surfaces, with Se0 aggregates having a diameter of 50-60 nm. Accumulation of Se0 within biofilms occurred over a three-week interval at a rate of c. 9 mg Se0 m(-2) tubing day(-1). Removal was inferred to result from the activity of a mixed microbial community within the biofilms capable of coupling acetate oxidation to the reduction of oxygen, nitrate and selenate. Phylogenetic analysis of the biofilm revealed a community dominated by strains of Dechloromonas sp. and Thauera sp., with isolates exhibiting genetic similarity to the latter known to reduce selenate to Se0. Enrichment cultures of selenate-respiring microorganisms were readily established using Rifle site groundwater and acetate, with cultures dominated by strains closely related to D. aromatica (96-99% similarity). Predominance of Dechloromonas sp. in recovered biofilms and enrichments suggests this microorganism may play a role in the removal of selenium oxyanions present in Se-impacted groundwaters and sediments.

Field evidence of selenium bioreduction in a uranium-contaminated aquifer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Williams , K. H.; Wilkins, Michael J.; N'Guessan, A. Lucie

2013-06-01

Removal of selenium from groundwater was documented during injection of acetate into a uraniumcontaminated aquifer near Rifle, Colorado (USA). Bioreduction of aqueous selenium to its elemental form (Se0) concentrated it within mineralized biofilms affixed to tubing used to circulate acetate-amended groundwater. Scanning and transmission electron microscopy revealed close association between Se0 precipitates and cell surfaces, with Se0 aggregates having a diameter of 50-60 nm. Accumulation of Se0 within biofilms occurred over a three-week interval at a rate of c. 9 mg Se0m-2 tubing day-1. Removal was inferred to result from the activity of a mixed microbial community within the biofilmsmore » capable of coupling acetate oxidation to the reduction of oxygen, nitrate and selenate. Phylogenetic analysis of the biofilm revealed a community dominated by strains of Dechloromonas sp. and Thauera sp., with isolates exhibiting genetic similarity to the latter known to reduce selenate to Se0. Enrichment cultures of selenate-respiring microorganisms were readily established using Rifle site groundwater and acetate, with cultures dominated by strains closely related to D. aromatica (96-99% similarity). Predominance of Dechloromonas sp. in recovered biofilms and enrichments suggests this microorganism may play a role in the removal of selenium oxyanions present in Se-impacted groundwaters and sediments.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Favorito, Jessica E.; Luxton, Todd P.; Eick, Matthew J.

Selenium is a trace element found in western US soils, where ingestion of Se-accumulating plants has resulted in livestock fatalities. Therefore, a reliable understanding of Se speciation and bioavailability is critical for effective mitigation. Sequential extraction procedures (SEP) are often employed to examine Se phases and speciation in contaminated soils but may be limited by experimental conditions. We examined the validity of a SEP using X-ray absorption spectroscopy (XAS) for both whole and a sequence of extracted soils. The sequence included removal of soluble, PO4-extractable, carbonate, amorphous Fe-oxide, crystalline Fe-oxide, organic, and residual Se forms. For whole soils, XANES analysesmore » indicated Se(0) and Se(-II) predominated, with lower amounts of Se(IV) present, related to carbonates and Fe-oxides. Oxidized Se species were more elevated and residual/elemental Se was lower than previous SEP results from ICP-AES suggested. For soils from the SEP sequence, XANES results indicated only partial recovery of carbonate, Fe-oxide and organic Se. This suggests Se was incompletely removed during designated extractions, possibly due to lack of mineral solubilization or reagent specificity. Selenium fractions associated with Fe-oxides were reduced in amount or removed after using hydroxylamine HCl for most soils examined. XANES results indicate partial dissolution of solid-phases may occur during extraction processes. This study demonstrates why precautions should be taken to improve the validity of SEPs. Mineralogical and chemical characterizations should be completed prior to SEP implementation to identify extractable phases or mineral components that may influence extraction effectiveness. Sequential extraction procedures can be appropriately tailored for reliable quantification of speciation in contaminated soils.« less

Arsenic and selenium in soils and shallow ground water in the Turtle Lake, New Rockford, Harvey Pumping, Lincoln Valley, and LaMoure irrigation areas of the Garrison Diversion Unit, North Dakota

USGS Publications Warehouse

Berkas, W.R.; Komor, S.C.

1996-01-01

The Garrison Diversion Unit project was authorized as part of the Pick-Sloan Missouri River Basin program to divert water from Lake Sakakawea to irrigation areas in North Dakota. A special Garrison Commission was created to evaluate an environmental concern that return flow from the irrigation areas might contain metals in toxic concentrations. This report summarizes the results of detailed investigations of the Turtle Lake, New Rockford, Harvey Pumping, Lincoln Valley, and LaMoure irrigation areas. A total of 223 soil samples were collected from the irrigation areas and analyzed for elemental composition. Water extractions were done on 40 of the 223 soil samples using a 1:5 soil-to-water extraction method, and the solution from the extraction was analyzed for elemental composition. A total of 52 ground-water samples were collected and analyzed for inorganic constituents and organic carbon.Average arsenic concentrations in the entire soil column ranged from 1.0 milligram per kilogram in the Harvey Pumping irrigation area to 70 milligrams per kilogram in the New Rockford irrigation area. Average selenium concentrations ranged from less than 0.1 milligram per kilogram in the Turtle Lake, New Rockford, Harvey Pumping, and Lincoln Valley irrigation areas to 6.0 milligrams per kilogram in the Turtle Lake irrigation area. In the Turtle Lake irrigation area, average arsenic and selenium concentrations generally increased with depth through the topsoil, oxidized soil, and transition soil but decreased in the reduced soil at the bottom of the sampled horizons. Average arsenic concentrations in the New Rockford irrigation area follow the same pattern as in the Turtle Lake irrigation area, but selenium concentrations do not show a clear pattern of variation with depth. In the Harvey Pumping and Lincoln Valley irrigation areas, arsenic and selenium concentrations do not appear to vary systematically with depth. No correlation is shown between the concentrations in soils and soil extracts, indicating that, based on conditions of laboratory soil-water extraction experiments, trace-element concentrations in soils are not good predictors of trace-element concentrations in irrigation return flow. Arsenic concentrations in the aquifers ranged from less than 1 microgram per liter to 27 micrograms per liter. Arsenic concentrations generally were larger in the deep part of the aquifers underlying the Turtle Lake and New Rockford irrigation areas than in the shallow part of the aquifers. In the shallow part of the aquifers, where oxidizing conditions prevail, arsenic is strongly adsorbed to soil particles. In the deep part of the aquifers, where reducing conditions prevail, arsenic is more mobile.Selenium concentrations in the aquifers ranged from less than 1 microgram per liter to 4 micrograms per liter. Little difference existed between the selenium concentrations in the shallow part of the aquifers underlying the irrigation areas and the concentrations in the deep part of the aquifers.

Sorption and speciation of selenium in boreal forest soil.

PubMed

Söderlund, Mervi; Virkanen, Juhani; Holgersson, Stellan; Lehto, Jukka

2016-11-01

Sorption and speciation of selenium in the initial chemical forms of selenite and selenate were investigated in batch experiments on humus and mineral soil samples taken from a 4-m deep boreal forest soil excavator pit on Olkiluoto Island, on the Baltic Sea coast in southwestern Finland. The HPLC-ICP-MS technique was used to monitor any possible transformations in the selenium liquid phase speciation and to determine the concentrations of selenite and selenate in the samples for calculation of the mass distribution coefficient, K d , for both species. Both SeO 3 2- and SeO 4 2- proved to be resistant forms in the prevailing soil conditions and no changes in selenium liquid phase speciation were seen in the sorption experiments in spite of variations in the initial selenium species, incubation time or conditions, pH, temperature or microbial activity. Selenite sorption on the mineral soil increased with time in aerobic conditions whilst the opposite trend was seen for the anaerobic soil samples. Selenite retention correlated with the contents of organic matter and weakly crystalline oxides of aluminum and iron, solution pH and the specific surface area. Selenate exhibited poorer sorption on soil than selenite and on average the K d values were 27-times lower. Mineral soil was more efficient in retaining selenite and selenate than humus, implicating the possible importance of weakly crystalline aluminum and iron oxides for the retention of oxyanions in Olkiluoto soil. Sterilization of the soil samples decreased the retention of selenite, thus implying some involvement of soil microbes in the sorption processes or a change in sample composition, but it produced no effect for selenate. There was no sorption of selenite by quartz, potassium feldspar, hornblende or muscovite. Biotite showed the best retentive properties for selenite in the model soil solution at about pH 8, followed by hematite, plagioclase and chlorite. The K d values for these minerals were 18, 14, 8 and 7 L/kg, respectively. It is proposed that selenite sorption is affected by the structural Fe(II) in biotite, which is capable of inducing the reduction of SeO 3 2- to Se(0). Selenite probably forms a surface complex with Fe(III) atoms on the surface of hematite, thus explaining its retention on this mineral. None of the minerals retained selenate to any extent. Copyright © 2016 Elsevier Ltd. All rights reserved.

Organic anodes and sulfur/selenium cathodes for advanced Li and Na batteries

NASA Astrophysics Data System (ADS)

Luo, Chao

To address energy crisis and environmental pollution induced by fossil fuels, there is an urgent demand to develop sustainable, renewable, environmental benign, low cost and high capacity energy storage devices to power electric vehicles and enhance clean energy approaches such as solar energy, wind energy and hydroenergy. However, the commercial Li-ion batteries cannot satisfy the critical requirements for next generation rechargeable batteries. The commercial electrode materials (graphite anode and LiCoO 2 cathode) are unsustainable, unrenewable and environmental harmful. Organic materials derived from biomasses are promising candidates for next generation rechargeable battery anodes due to their sustainability, renewability, environmental benignity and low cost. Driven by the high potential of organic materials for next generation batteries, I initiated a new research direction on exploring advanced organic compounds for Li-ion and Na-ion battery anodes. In my work, I employed croconic acid disodium salt and 2,5-Dihydroxy-1,4-benzoquinone disodium salt as models to investigate the effects of size and carbon coating on electrochemical performance for Li-ion and Na-ion batteries. The results demonstrate that the minimization of organic particle size into nano-scale and wrapping organic materials with graphene oxide can remarkably enhance the rate capability and cycling stability of organic anodes in both Li-ion and Na-ion batteries. To match with organic anodes, high capacity sulfur and selenium cathodes were also investigated. However, sulfur and selenium cathodes suffer from low electrical conductivity and shuttle reaction, which result in capacity fading and poor lifetime. To circumvent the drawbacks of sulfur and selenium, carbon matrixes such as mesoporous carbon, carbonized polyacrylonitrile and carbonized perylene-3, 4, 9, 10-tetracarboxylic dianhydride are employed to encapsulate sulfur, selenium and selenium sulfide. The resulting composites exhibit exceptional electrochemical performance owing to the high conductivity of carbon and effective restriction of polysulfides and polyselenides in carbon matrix, which avoids shuttle reaction.

Does static magnetic field-exposure induced oxidative stress and apoptosis in rat kidney and muscle? Effect of vitamin E and selenium supplementations.

PubMed

Ghodbane, Soumaya; Lahbib, Aida; Ammari, Mohamed; Sakly, Mohsen; Abdelmelek, Hafedh

2015-01-01

Static magnetic fields (SMFs) effect observed with radical pair recombination is one of the well-known mechanisms by which SMFs interact with biological systems. Our aim was to study whether SMF induces oxidative stress and apoptosis in rat tissues and to evaluate the possible protector effect of selenium (Se) and vitamin E (vit E) supplementations. Rats were randomly divided into control, SMF-exposed, Se-treated, vit E-treated, SMF exposed rats and co-treated with Se, and SMF exposed rats and co-treated with vit E. After animal sacrifice, catalase (CAT) activity and malondialdehyde (MDA) concentration were measured and apoptosis inducing factor (AIF) immunohistochemical labeling was performed in kidney and muscle. Exposure of rats to SMF (128 mT, 1 h/day for 5 days) increased the MDA concentrations (+25%) and CAT activities (+34%) in kidney but not in muscle. By contrast, the same treatment failed to induce a caspase-independent pathway apoptosis in both tissues. Interestingly, Se pre-treatment inhibited the increase of MDA concentrations and CAT activities in kidney in SMF-exposed rats. However, vit E administration corrected only MDA levels in rat kidney. In conclusion, exposure to SMF induced oxidative stress in kidney that can be prevented by treatment with Se or vit E.

N-acetyl cysteine, L-cysteine, and beta-mercaptoethanol augment selenium-glutathione peroxidase activity in glucose-6-phosphate dehydrogenase-deficient human erythrocytes.

PubMed

Alicigüzel, Y; Aslan, M

2004-09-01

In glucose-6-phosphate dehydrogenase (G6PD)-deficient erythrocytes, failure to maintain normal levels of reduced glutathione (GSH) due to decreased NADPH regeneration in the hexose monophosphate pathway results in acute hemolytic anemia following exposure to oxidative insults, such as ingestion of Vicia fava beans or use of certain drugs. GSH is a source of protection against oxidative attack, used by the selenium-dependent glutathione peroxidase (Se-GSH-Px)/reductase (GR) system to detoxify hydrogen peroxide and organic peroxides, provided that sufficient GSH is made available. In this study, Se-GSH-Px activity was analyzed in G6PD-deficient patients in the presence of reducing agents such as N-Acetyl cysteine, L-cysteine, and beta-mercaptoethanol. Se-GSH-Px activity was decreased in G6PD-deficient red blood cells (RBCs). N-Acetyl cysteine, L-cysteine, and beta-mercaptoethanol increased Se-GSH-Px activity in G6PD-deficient human erythrocytes, indicating that other reducing agents can be utilized to complement Se-GSH-Px activity in G6PD deficiency. Based on the increased susceptibility of G6PD-deficient patients to oxidative stress, the reported increase in Se-GSH-Px activity can facilitate the detoxification of reactive oxygen species.

Effects of salinity on the toxicity and biotransformation of L-selenomethionine in Japanese medaka (Oryzias latipes) embryos: mechanisms of oxidative stress.

PubMed

Lavado, Ramon; Shi, Dalin; Schlenk, Daniel

2012-02-01

Previous studies in mammals have shown that organoselenium depletes the cellular antioxidant, glutathione (GSH) due to activation of organoselenides to organoselenoxides by flavin-containing monooxygenases (FMO). Since FMO tends to be induced in euryhaline fish exposed to hypersaline conditions, the developmental toxicity of salinity and organoselenium was examined in the euryhaline fish Japanese medaka (Oryzias latipes). FMO activity, GSH, and selenium concentrations in Japanese medaka embryos were measured following a 24-h exposure to 0.05 mM L-selenomethionine (SeMet) under different saline conditions: freshwater (<0.5 dS/m), 4.2, 6.7, and 16.8 dS/m. Concentrations of GSH and the hatch-out ratio of the SeMet-treated embryos decreased in a salinity dependent manner. While SeMet treatment led to accumulation within embryos, selenium concentrations were unaltered by salinity treatment. Compared to freshwater-exposed embryos, microsomes from embryos at 6.7 and 16.8 dS/m had enhanced oxidation of SeMet to the selenoxide (10- and 14.3-fold, respectively), which correlated with GSH depletion. The results show that increased SeMet oxidation by hypersaline conditions with subsequent GSH depletion may play an important role in the developmental toxicity of selenomethionine. Copyright © 2011 Elsevier B.V. All rights reserved.

Fluorine-induced apoptosis and lipid peroxidation in human hair follicles in vitro.

PubMed

Wang, Zheng-hui; Li, Xiao-li; Yang, Zhuang-qun; Xu, Min

2010-12-01

Fluoride is an essential trace element for human body; however, exposure to high amounts of fluoride has been documented to be correlated with an increasing risk of hair loss. To date, little is known about the mechanism(s) of how fluoride affects hair follicles. Here, we demonstrated that middle (1.0 mmol/L) and high (10.0 mmol/L) concentrations of sodium fluoride (NaF) significantly inhibited hair follicle elongation in vitro, but low NaF (0.1 mmol/L) showed little influence. Moreover, treatment with high levels of NaF resulted in a marked increase in terminal dUTP nick end labeling-positive cells in the outer layer of the outer root sheath, the dermal sheath, and the lower bulb matrix surrounding dermal papilla. Furthermore, the enhanced apoptosis was coupled with an increased oxidative stress manifested as higher malondialdehyde content. Additionally, the presence of selenium considerably antagonized the effects of middle NaF on hair follicles, with regard to either the suppression of hair growth or the induction of oxidative stress and apoptosis. In conclusion, exposure to high levels of fluoride compromises hair follicle growth and accelerate cell apoptosis in vitro. The toxicity of fluoride can be reduced by selenium, at least partially via the suppression of intracellular oxidative stress.

Lateral amorphous selenium metal-insulator-semiconductor-insulator-metal photodetectors using ultrathin dielectric blocking layers for dark current suppression

NASA Astrophysics Data System (ADS)

Chang, Cheng-Yi; Pan, Fu-Ming; Lin, Jian-Siang; Yu, Tung-Yuan; Li, Yi-Ming; Chen, Chieh-Yang

2016-12-01

We fabricated amorphous selenium (a-Se) photodetectors with a lateral metal-insulator-semiconductor-insulator-metal (MISIM) device structure. Thermal aluminum oxide, plasma-enhanced chemical vapor deposited silicon nitride, and thermal atomic layer deposited (ALD) aluminum oxide and hafnium oxide (ALD-HfO2) were used as the electron and hole blocking layers of the MISIM photodetectors for dark current suppression. A reduction in the dark current by three orders of magnitude can be achieved at electric fields between 10 and 30 V/μm. The effective dark current suppression is primarily ascribed to electric field lowering in the dielectric layers as a result of charge trapping in deep levels. Photogenerated carriers in the a-Se layer can be transported across the blocking layers to the Al electrodes via Fowler-Nordheim tunneling because a high electric field develops in the ultrathin dielectric layers under illumination. Since the a-Se MISIM photodetectors have a very low dark current without significant degradation in the photoresponse, the signal contrast is greatly improved. The MISIM photodetector with the ALD-HfO2 blocking layer has an optimal signal contrast more than 500 times the contrast of the photodetector without a blocking layer at 15 V/μm.

Bacterial respiration of arsenic and selenium

USGS Publications Warehouse

Stolz, J.F.; Oremland, R.S.

1999-01-01

Oxyanions of arsenic and selenium can be used in microbial anaerobic respiration as terminal electron acceptors. The detection of arsenate and selenate respiring bacteria in numerous pristine and contaminated environments and their rapid appearance in enrichment culture suggest that they are widespread and metabolically active in nature. Although the bacterial species that have been isolated and characterized are still few in number, they are scattered throughout the bacterial domain and include Gram- positive bacteria, beta, gamma and epsilon Proteobacteria and the sole member of a deeply branching lineage of the bacteria, Chrysiogenes arsenatus. The oxidation of a number of organic substrates (i.e. acetate, lactate, pyruvate, glycerol, ethanol) or hydrogen can be coupled to the reduction of arsenate and selenate, but the actual donor used varies from species to species. Both periplasmic and membrane-associated arsenate and selenate reductases have been characterized. Although the number of subunits and molecular masses differs, they all contain molybdenum. The extent of the environmental impact on the transformation and mobilization of arsenic and selenium by microbial dissimilatory processes is only now being fully appreciated.

Enhanced antioxidant activity of gold nanoparticle embedded 3,6-dihydroxyflavone: a combinational study

NASA Astrophysics Data System (ADS)

Medhe, Sharad; Bansal, Prachi; Srivastava, Man Mohan

2014-02-01

The antioxidative effect of selected dietary compounds (3,6-dihydroxyflavone, lutein and selenium methyl selenocysteine) was determined in single and combination using DPPH (2,2-diphenyl-l-picrylhydrazyl), OH (hydroxyl), H2O2 (hydrogen peroxide) and NO (nitric oxide) radical scavenging assays. Radical scavenging effect of the dietary phytochemicals individually are found to be in the order: ascorbic acid (standard) > lutein > 3,6-dihydroxyflavone > selenium methyl selenocysteine, at concentration 100 μg/ml, confirmed by all the four bioassays (p < 0.05). Among the various combinations studied, the triplet combination of 3,6-dihydroxyflavone, lutein and selenium methyl selenocysteine (1:1:1), exhibited enhancement in the target activity at same concentration level. Synthesized gold nanoparticle embedded 3,6-dihydroxyflavone further enhanced the target antioxidant activity. The combinational study including gold nanoparticle embedded 3,6-dihydroxyflavone with other native dietary nutrients showed remarkable increase in antioxidant activity at the same concentration level. The present in vitro study on combinational and nanotech enforcement of dietary phytochemicals shows the utility in the architecture of nanoparticle embedded phytoproducts having a wide range of applications in medical science.

Selenium and Antioxidant Status in Dairy Cows at Different Stages of Lactation.

PubMed

Gong, Jian; Xiao, Min

2016-05-01

Thirty-five multiparous Holstein cows averaging 550 ± 50 kg of body weight and in 2 to 4 parity were divided into three groups according to lactation stage (group A: nine cows from 4 to 1 weeks prepartum; group B: 11 cows from 1 to 30 days postpartum; group C: 15 cows from 30 to 100 days postpartum). Selenium concentration, malondialdehyde (MDA) level, glutathione peroxidase (GSH-Px) activity, thioredoxin reductase (TrxR) activity, and total antioxidant status (TAS) in serum were determined to evaluate selenium and antioxidant status in dairy cows at different stages of lactation. The results showed that mean serum selenium concentration, MDA level, and GSH-Px activity of cows in early lactation increased significantly (P < 0.05) when compared with cows in the dry period and peak lactation. Conversely, serum TrxR activity and TAS declined during this period (P < 0.05). The increase of serum MDA level during early lactation indicate that the reactive oxygen species, including lipid hydroperoxides, increase in this period, thus placing the cows at a greater risk of oxidative stress. The significant decrease in TrxR activity that is accompanied with a decrease in TAS during early lactation suggests that dairy cows have low antioxidant defense in this period and TrxR may be an important antioxidant defense mechanism in transition dairy cows.

Standard methods for chemical analysis of steel, cast iron, open-hearth iron, and wrought iron

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

1973-01-01

Methods are described for determining manganese, phosphorus, sulfur, selenium, copper, nickel, chromium, vanadium, tungsten, titanium, lead, boron, molybdenum ( alpha -benzoin oxime method), zirconium (cupferron --phosphate method), niobium and tantalum (hydrolysis with perchloric and sulfurous acids (gravimetric, titrimetric, and photometric methods)), and beryllium (oxide method). (DHM)

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

USGS Publications Warehouse

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.

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

NASA Astrophysics Data System (ADS)

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 (p<0.05) difference in the levels of ALP and MDA in group B, while a significant difference was observed in the levels of ALP, total protein, CAT and MDA in group G when compared with the parasitized group. Histopathological analysis showed no presence of inflammatory cells 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.

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

PubMed

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 real target therapy in thyroid dysfunction. The publisher would like to apologise for any inconvenience caused. [corrected].

Selenium alleviates chromium toxicity by preventing oxidative stress in cabbage (Brassica campestris L. ssp. Pekinensis) leaves.

PubMed

Qing, Xuejiao; Zhao, Xiaohu; Hu, Chengxiao; Wang, Peng; Zhang, Ying; Zhang, Xuan; Wang, Pengcheng; Shi, Hanzhi; Jia, Fen; Qu, Chanjuan

2015-04-01

The beneficial role of selenium (Se) in alleviation of chromium (Cr)-induced oxidative stress is well established. However, little is known about the underlying mechanism. The impacts of exogenous Se (0.1mg/L) on Cr(1mg/L)-induced oxidative stress and antioxidant systems in leaves of cabbage (Brassica campestris L. ssp. Pekinensis) were investigated by using cellular and biochemical approaches. The results showed that supplementation of the medium with Se was effective in reducing Cr-induced increased levels of lipid peroxides and superoxide free radicals (O(-)2(·)), as well as increasing activities of superoxide dismutase (SOD) and peroxidase (POD). Meanwhile, 1mg/L Cr induced loss of plasma membrane integrity, growth inhibition, as well as ultrastructural changes of leaves were significantly reversed due to Se supplementation in the medium. In addition, Se application significantly altered the subcellular distribution of Cr which transported from mitochondria, nucleus and the cell-wall material to the soluble fraction and chloroplasts. However, Se application did no significant alteration of Cr effects on osmotic adjustment accumulating products. The study suggested that Se is able to protect leaves of cabbage against Cr toxicity by alleviation of Cr induced oxidative stress, and re-distribution of Cr in the subcellular of the leaf. Furthermore, free radicals, lipid peroxides, activity of SOD and POD, and subcellular distribution of Cr can be considered the efficient biomarkers to indicate the efficiency of Se to detoxification Cr. Copyright © 2015 Elsevier Inc. All rights reserved.

Blockage of both the extrinsic and intrinsic pathways of diazinon-induced apoptosis in PaTu cells by magnesium oxide and selenium nanoparticles.

PubMed

Shiri, Mahdi; Navaei-Nigjeh, Mona; Baeeri, Maryam; Rahimifard, Mahban; Mahboudi, Hossein; Shahverdi, Ahmad Reza; Kebriaeezadeh, Abbas; Abdollahi, Mohammad

Diazinon (DZ) is an organophosphorus insecticide that acts as an acetylcholinesterase inhibitor. It is important to note that it can induce oxidative stress, lipid peroxidation, diabetic disorders, and cytotoxicity. Magnesium oxide (MgO) and selenium nanoparticles (Se NPs) showed promising protection against oxidative stress, lipid peroxidation, cytotoxicity, and diabetic disorders. Therefore, this study was conducted to explore the possible protective mechanisms of MgO and Se NPs against DZ-induced cytotoxicity in PaTu cell line. Cytotoxicity of DZ, in the presence or absence of effective doses of MgO and Se NPs, was determined in human pancreatic cancer cell line (PaTu cells) after 24 hours of exposure by using mitochondrial activity and mitochondrial membrane potential assays. Then, the insulin, proinsulin, and C-peptide release; caspase-3 and -9 activities; and total thiol molecule levels were assessed. Determination of cell viability, including apoptotic and necrotic cells, was assessed via acridine orange/ethidium bromide double staining. Furthermore, expression of 15 genes associated with cell death/apoptosis in various phenomena was examined after 24 hours of contact with DZ and NPs by using real-time polymerase chain reaction. Compared to the individual cases, the group receiving the combination of MgO and Se NPs showed more beneficial effects in reducing the toxicity of DZ. Cotreatment of PaTu cell lines with MgO and Se NPs counteracts the toxicity of DZ on insulin-producing cells.

Pre-Clinical Study for the Antidiabetic Potential of Selenium Nanoparticles.

PubMed

Ahmed, Hanaa H; Abd El-Maksoud, Mohamed Diaa; Abdel Moneim, Ahmed E; Aglan, Hadeer A

2017-06-01

This research was delineated to explore the efficacy of selenium nanoparticles delivered in liposomes (L-Se) in the mitigation of type-2 diabetes mellitus. Adult female Wistar rats were assigned into four groups: group I, the normal control group in which the rats received normal saline solution orally; group II, the diabetic control group in which the rats were injected intraperitoneally with a single dose of streptozotocin (STZ) for induction of diabetes; group III, the metformin (Met)-treated group in which the diabetic rats were treated orally with Met; and group IV, the L-Se-treated group in which the diabetic rats were treated orally with L-Se. All treatments were delivered for 21 days. Blood and pancreas tissue samples were obtained for biochemical analysis, immunohistochemical examinations, and histopathological investigation. The L-Se-treated group showed significant drop in serum glucose and pancreatic malondialdehyde (MDA), nitric oxide (NO), tumor necrosis factor-α (TNF-α), and prostaglandin F2α (PGF2α) levels associated with significant rise in serum insulin and pancreatic glutathione, superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), and glutathione reductase (GR) values, in addition to significant improvement in the immunohistochemical indices (insulin and glucagon). Aforementioned results are appreciated by the histopathological findings of pancreatic tissue. In conclusion, our data have brought about compelling evidence favoring the antidiabetic potency of elemental selenium nanoparticles delivered in liposomes through preservation of pancreatic β cell integrity with consequent increment of insulin secretion and in turn glucose depletion, repression of oxidative stress, potentiation of the antioxidant defense system, and inhibition of pancreatic inflammation.

Bioreduction of Selenium Oxyanions via the Feammox Process

NASA Astrophysics Data System (ADS)

Sherman, A.; Jaffe, P. R.

2017-12-01

Selenium (Se) is an important environmental contaminant found in both agricultural and industrial wastewater. A novel bacterium, Acidimicrobiaceae bacterium A6 (hereon referred to as A6), has been shown to oxidize ammonium through the reduction of iron oxides (termed the Feammox process) and has also been shown to reduce trace metals and radionuclides. This research aims to establish whether the Feammox process can be used to reduce Se oxyanions in wastewater, and to determine the pathway by which this reduction occurs. A novel method of Se analysis using ion chromatography (Dionex Aquion IC system, AS18 separator and guard columns, 18mM KOH eluent, 45mA) has been developed, showing clear resolution of SeO32- and SeO42- peaks and detection limits in the ppb range. Batch incubations were run using pure A6 culture to tie the reduction of Se to the activity of this bacterium. Nontronite was used as the iron source to sustain A6 activity. Unlike other iron sources, such as ferrihydrite, nontronite does not sorb Se oxyanions, and thus selenium remains bioavailable as an electron acceptor for use during the Feammox process. Concentrations of 1ppm of SeO32- and SeO42- were used, below the toxic threshold for A6, and incubations were sampled destructively over the course of 8 days. Samples were analyzed using ion chromatography and UV-Vis spectroscopy to determine bacterial activity and chemical speciation. Initial results indicate that A6 may be able to reduce 300ppb of SeO32-in 3 days, however more work is needed to further explain this result.

Selenomethionine and alpha-tocopherol do not inhibit prostate carcinogenesis in the testosterone plus estradiol-treated NBL rat model.

PubMed

Ozten, Nur; Horton, Lori; Lasano, Salamia; Bosland, Maarten C

2010-03-01

Previous studies with selenium and/or vitamin E in prostate carcinogenesis animal models have been negative, but these models may not involve oxidative stress mechanisms. In this study, we examined the potential of selenomethionine and alpha-tocopherol to modulate prostate cancer development in the testosterone plus estradiol-treated NBL rat, a model that does involve sex hormone-induced oxidative stress mechanisms and prostatic inflammation. One week following the implantation with hormone-filled Silastic implants, rats were fed diets containing l-selenomethionine (1.5 or 3.0 mg/kg), DL-alpha-tocopherol acetate (2,000 or 4,000 mg/kg), or a natural ingredient control diet (NIH-07). The development of prostate carcinomas was not affected by dietary treatment with either agent. Food intake, body weight, and mortality were also not affected. The high dose of selenomethionine reduced the severity of epithelial dysplasia in the lateral prostate that was not associated with inflammation, and alpha-tocopherol reduced in a dose-related fashion the incidence of marked inflammation and marked epithelial dysplasia in the lateral prostate, regardless of whether these lesions were associated with inflammation. alpha-Tocopherol significantly increased the incidence of adenocarcinomas of the mammary glands at both dietary concentrations. Collectively, our findings suggest that selenomethionine and alpha-tocopherol supplementation does not prevent prostate cancer in rats fed diets with nutritionally adequate levels of selenium and vitamin E. Importantly, the results of the current animal studies and those reported previously were fully predictive of the outcome of the Selenium and Vitamin E Cancer Prevention Trial.

Oxidation at C-16 enhances butyrylcholinesterase inhibition in lupane triterpenoids.

PubMed

Castro, María Julia; Richmond, Victoria; Faraoni, María Belén; Murray, Ana Paula

2018-05-17

A set of triterpenoids with different grades of oxidation in the lupane skeleton were prepared and evaluated as cholinesterase inhibitors. Allylic oxidation with selenium oxide and Jones's oxidation were employed to obtain mono-, di- and tri-oxolupanes, starting from calenduladiol (1) and lupeol (3). All the derivatives showed a selective inhibition of butyrylcholinesterase over acetylcholinesterase (BChE vs. AChE). A kinetic study proved that compounds 2 and 9, the more potent inhibitors of the series, act as competitive inhibitors. Molecular modeling was used to understand their interaction with BChE, the role of carbonyl at C-16 and the selectivity towards this enzyme over AChE. These results indicate that oxidation at C-16 of the lupane skeleton is a key transformation in order to improve the cholinesterase inhibition of these compounds. Copyright © 2018 Elsevier Inc. All rights reserved.

77 FR 20034 - Harmful and Potentially Harmful Constituents in Tobacco Products and Tobacco Smoke; Established List

Federal Register 2010, 2011, 2012, 2013, 2014

2012-04-03

... DEPARTMENT OF HEALTH AND HUMAN SERVICES Food and Drug Administration [Docket No. FDA-2012-N-0143...]pyridine). Polonium-210 CA Propionaldehyde RT, CT Propylene oxide CA, RT Quinoline CA Selenium RT Styrene... AGENCY: Food and Drug Administration, HHS. ACTION: Notice; establishment of a list. SUMMARY: The Food and...

Compositions and methods for removing arsenic in water

DOEpatents

Gadgil, Ashok Jagannth [El Cerrito, CA

2011-02-22

Compositions and methods and for contaminants from water are provided. The compositions comprise ferric hydroxide and ferric oxyhydride coated substrates for use in removing the contaminant from the water. Contacting water bearing the contaminant with the substrates can substantially reduce contaminant levels therein. Methods of oxidizing the contaminants in water to facilitate their removal by the ferric hydroxide and ferric oxyhydride coated substrates are also provided. The contaminants include, but are not limited to, arsenic, selenium, uranium, lead, cadmium, nickel, copper, zinc, chromium and vanadium, their oxides and soluble salts thereof.

The Influence of Selenium Yeast on Hematological, Biochemical and Reproductive Hormone Level Changes in Kunming Mice Following Acute Exposure to Zearalenone.

PubMed

Long, Miao; Yang, Shuhua; Zhang, Wenkui; Zhang, Yi; Li, Peng; Guo, Yang; Wang, Yuan; Chen, Xinliang; He, Jianbin

2016-12-01

Healthy male Kunming mice received selenium yeast for 14 days prior to a single oral administration of zearalenone (ZEN). After 48 h, blood samples were collected for analysis and showed that mice in the ZEN-treated group has significantly decreased lymphocytes (P < 0.05) and platelets (P < 0.05) along with an increased white blood cell (WBC) count and other constituents (P < 0.05). The serum biochemistry analysis of the ZEN group indicated that glutamic pyruvic transaminase (ALT), glutamic oxaloacetic transaminase (AST), urea, and uric acid were significantly increased (P < 0.05), whilst total bilirubin (TB) and albumin (ALB) were decreased along with serum testosterone and estrogen (P < 0. 05). The level of malondialdehyde (MDA) in the serum of the ZEN group was significantly increased whilst glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) had significantly decreased (P < 0.05). Treatment with selenium yeast had a significant effect on response with most of the experimental parameters returning to levels similar to those observed in the untreated control mice. From these data, it can be concluded that ZEN is highly poisonous in Kunming mice with high levels of toxicity on the blood, liver, and kidneys. High levels of oxidative stress were observed in mice and pre-treatment with selenium yeast by oral gavage is effective in the ameliorated effects of ZEN-induced damage.

Improved selectivity for Pb(II) by sulfur, selenium and tellurium analogues of 1,8-anthraquinone-18-crown-5: synthesis, spectroscopy, X-ray crystallography and computational studies.

PubMed

Mariappan, Kadarkaraisamy; Alaparthi, Madhubabu; Hoffman, Mariah; Rama, Myriam Alcantar; Balasubramanian, Vinothini; John, Danielle M; Sykes, Andrew G

2015-07-14

We report here a series of heteroatom-substituted macrocycles containing an anthraquinone moiety as a fluorescent signaling unit and a cyclic polyheteroether chain as the receptor. Sulfur, selenium, and tellurium derivatives of 1,8-anthraquinone-18-crown-5 (1) were synthesized by reacting sodium sulfide (Na2S), sodium selenide (Na2Se) and sodium telluride (Na2Te) with 1,8-bis(2-bromoethylethyleneoxy)anthracene-9,10-dione in a 1 : 1 ratio. The optical properties of the new compounds are examined and the sulfur and selenium analogues produce an intense green emission enhancement upon association with Pb(II) in acetonitrile. Selectivity for Pb(II) is markedly improved as compared to the oxygen analogue 1 which was also competitive for Ca(II) ion. UV-Visible and luminescence titrations reveal that 2 and 3 form 1 : 1 complexes with Pb(II), confirmed by single-crystal X-ray studies where Pb(II) is complexed within the macrocycle through coordinate covalent bonds to neighboring carbonyl, ether and heteroether donor atoms. Cyclic voltammetry of 2-8 showed classical, irreversible oxidation potentials for sulfur, selenium and tellurium heteroethers in addition to two one-electron reductions for the anthraquinone carbonyl groups. DFT calculations were also conducted on 1, 2, 3, 6, 6 + Pb(II) and 6 + Mg(II) to determine the trend in energies of the HOMO and the LUMO levels along the series.

Role of cobalt, iron, lead, manganese, mercury, platinum, selenium, and titanium in carcinogenesis.

PubMed Central

Kazantzis, G

1981-01-01

The possible carcinogenicity of cobalt, iron, lead, manganese, mercury, platinum, selenium, and titanium is reviewed, taking into account epidemiological data, the results of animal experimental studies, data on mutagenic effects and on other in vitro test systems. Of the great variety of occupations where exposure to one of these metals may occur, only haematite mining has been clearly shown to involve an increased human cancer risk. While the possibility that haematite might in some way act as a carcinogen has to be taken into consideration it is more likely that other carcinogens are responsible. Certain platinum coordination complexes are used in cancer chemotherapy, are mutagenic, and likely to be carcinogenic. Cobalt, its oxide and sulfide, certain lead salts, one organomanganese, and one organotitanium compound have been shown to have a limited carcinogenic effect in experimental animal studies, and except for titanium appear to be mutagenic. Certain mercury compounds are mutagenic but none have been shown to be carcinogenic. The presently available data are inadequate to assess the possible carcinogenicity of selenium compounds, but a few observations suggest that selenium may suppress the effect of other carcinogens administered to experimental animals and may even be associated with lower cancer mortality rates in man. Epidemiological observations are essential for the assessment of a human cancer risk, but the difficulty in collecting past exposure data in occupational groups and the complexity of multiple occupational exposures with changes over time, limits the usefulness of retrospective epidemiological studies. PMID:7023929

Structural and Spectral Features of Selenium Nanospheres Produced by Se-Respiring Bacteria

USGS Publications Warehouse

Oremland, R.S.; Herbel, M.J.; Blum, J.S.; Langley, S.; Beveridge, T.J.; Ajayan, P.M.; Sutto, T.; Ellis, A.V.; Curran, S.

2004-01-01

Certain anaerobic bacteria respire toxic selenium oxyanions and in doing so produce extracellular accumulations of elemental selenium [Se(0)]. We examined three physiologically and phylogenetically diverse species of selenate- and selenite-respiring bacteria, Sulfurospirillum barnesii, Bacillus selenitireducens, and Selenihalanaerobacter shriftii, for the occurrence of this phenomenon. When grown with selenium oxyanions as the electron acceptor, all of these organisms formed extracellular granules consisting of stable, uniform nanospheres (diameter, ???300 nm) of Se(0) having monoclinic crystalline structures. Intracellular packets of Se(0) were also noted. The number of intracellular Se(0) packets could be reduced by first growing cells with nitrate as the electron acceptor and then adding selenite ions to washed suspensions of the nitrate-grown cells. This resulted in the formation of primarily extracellular Se nanospheres. After harvesting and cleansing of cellular debris, we observed large differences in the optical properties (UV-visible absorption and Raman spectra) of purified extracellular nanospheres produced in this manner by the three different bacterial species. The spectral properties in turn differed substantially from those of amorphous Se(0) formed by chemical oxidation of H2Se and of black, vitreous Se(0) formed chemically by reduction of selenite with ascorbate. The microbial synthesis of Se(0) nanospheres results in unique, complex, compacted nanostructural arrangements of Se atoms. These arrangements probably reflect a diversity of enzymes involved in the dissimilatory reduction that are subtly different in different microbes. Remarkably, these conditions cannot be achieved by current methods of chemical synthesis.

Selenium Supplementation Affects Insulin Resistance and Serum hs-CRP in Patients with Type 2 Diabetes and Coronary Heart Disease.

PubMed

Farrokhian, A; Bahmani, F; Taghizadeh, M; Mirhashemi, S M; Aarabi, M H; Raygan, F; Aghadavod, E; Asemi, Z

2016-04-01

To our knowledge, this study is the first indicating the effects of selenium supplementation on metabolic status of patients with type 2 diabetes mellitus (T2DM) and coronary heart disease (CHD). This study was conducted to evaluate the effects of selenium supplementation on metabolic profiles, biomarkers of inflammation, and oxidative stress of patients with T2DM and CHD. This randomized, double-blind, placebo-controlled trial was performed among 60 patients with T2DM and CHD aged 40-85 years. Participants were randomly divided into 2 groups. Group A received 200 μg selenium supplements (n=30) and group B received placebo per day (n=30) for 8 weeks. Fasting blood samples were taken at the beginning of the study and after 8-week intervention to quantify metabolic profiles. After 8 weeks, compared with the placebo, selenium supplementation resulted in a significant decrease in serum insulin levels (- 2.2±4.6 vs. + 3.6±8.4 μIU/ml, p=0.001), homeostasis model of assessment-insulin resistance (HOMA-IR) (- 0.7±1.3 vs. + 0.9±2.4, p=0.004), homeostatic model assessment-beta cell function (HOMA-B) (- 7.5±17.2 vs. + 15.1±34.5, p=0.002) and a significant increase in quantitative insulin sensitivity check index (QUICKI) (+0.01±0.03 vs. - 0.01±0.03, p=0.02). In addition, patients who received selenium supplements had a significant reduction in serum high-sensitivity C-reactive protein (hs-CRP) (- 1 372.3±2 318.8 vs. - 99.8±1 453.6 ng/ml, p=0.01) and a significant rise in plasma total antioxidant capacity (TAC) concentrations (+ 301.3±400.6 vs. - 127.2±428.0 mmol/l, p<0.001) compared with the placebo. A 200 μg/day selenium supplementation among patients with T2DM and CHD resulted in a significant decrease in insulin, HOMA-IR, HOMA-B, serum hs-CRP, and a significant increase in QUICKI score and TAC concentrations. © Georg Thieme Verlag KG Stuttgart · New York.

Metabolic and immune response of young turkeys originating from parent flocks fed diets with inorganic or organic selenium.

PubMed

Jankowski, J; Zduńczyk, Z; Sartowska, K; Tykałowski, B; Stenzel, T; Wróblewska, M; Koncicki, A

2011-01-01

The aim of this study was to verify the hypothesis that the health and growth of turkey poults may be improved by supplementing diets fed to parent flocks with available selenium. Experimental poults originated from parent flocks fed with diets containing 0.3 mg/kg inorganic selenium (control group Se(M)) and organic selenium (experimental group Se(O)). Egg yolk selenium content was comparable in both flocks (0.72 and 0.70 mg/kg d.m., respectively). Eggs from the Se(O) flock had a significantly lower content of thiobarbituric acid reactive substances - TBARS (31.13 vs. 53.10 nmol/g, p > 0.001). Se(O) group poults were characterized by higher activity of glutathione peroxidase (7.54 vs. 5.92 U/mL, P = 0.001) and superoxide dismutase (89.30 vs. 79.23 U/mL, P = 0.026). The thigh muscles of Se(O) group birds had significantly higher selenium concentrations (0.74 vs. 0.57, p = 0.045) and a significantly lower TBARS content (38.42 vs. 65.01, p = 0.001). No differences were found between the groups with respect to the content of total protein, albumins and uric acid, and the activites of alanine aminotransferase (ALT), aspartate aminotransferase (AST) and lactate dehydrogenase (DLH) in day-old poults. On day 28, groups Se(O) and Se(M) differed in the activity of ALT (20.50 vs. 26.33, p = 0.05) and SOD (87.29 vs. 100.02 U/mL, p = 0.035). There were no differences between the groups regarding the percentages of T lymphocyte subpopulations CD4+, CD8+, CD4+CD8+ and B lymphocyte subpopulations (IgM+) at 1 and 28 days of age. Over the experimental period, mortality rates were similar in both groups (7.32 and 8.87%), and so were the final body weights of birds (1108 vs. 1135 g). The results of the study show that the dietary supplementation of organic selenium in turkey parent flocks reduces the rate of oxidation processes in the egg and in the tissues of newly-hatched poults, yet it has no effect on the analyzed parameters of cell-mediated immunity and the growth performance of birds during the first five weeks of their life.

The potential toxicological insights about the anti-HIV drug azidothymidine-derived monoselenides in human leukocytes: Toxicological insights of new selenium-azidothymidine analogs.

PubMed

Mariano, Doc; de Souza, D; Meinerz, D F; Allebrandt, J; de Bem, A F; Hassan, W; Rodrigues, Oed; da Rocha, Jbt

2017-09-01

Acquired immunodeficiency syndrome (AIDS) is a worldwide disease characterized by impairments of immune function. AIDS can be associated with oxidative stress (OS) that can be linked to selenium (Se) deficiency. Se is fundamental for the synthesis of selenoproteins, such as glutathione peroxidase and thioredoxin reductase. These enzymes catalyze the decomposition of reactive oxygen species and contribute to maintain equilibrium in cell redox status. Literature data indicate that organoselenium compounds, such as ebselen and diphenyl diselenide, have antioxidant properties in vitro and in vivo models associated with OS. Nevertheless, selenocompounds can also react and oxidize thiols groups, inducing toxicity in mammals. Here, we tested the potential cytotoxic and genotoxic properties of six analogs of the prototypal anti-HIV drug azidothymidine (AZT) containing Se (5'-Se-(phenyl)zidovudine; 5'-Se-(1,3,5-trimethylphenyl)zidovudine; 5'-Se-(1-naphtyl)zidovudine; 5'-Se-(4-chlorophenyl)zidovudine) (C4); 5'-Se-(4-methylphenyl)zidovudine (C5); and 5'-(4-methylbenzoselenoate)zidovudine). C5 increased the rate of dithiothreitol oxidation (thiol oxidase activity) and C2-C4 and C6 (at 100 µM) increased DNA damage index (DI) in human leukocytes. Moreover, C5 (200 µM) decreased human leukocyte viability to about 50%. Taken together, these results indicated the low in vitro toxicity in human leukocytes of some Se-containing analogs of AZT.

Electron Paramagnetic Resonance (EPR) Spectroscopy in Studies of the Protective Effects of 24-Epibrasinoide and Selenium against Zearalenone-Stimulation of the Oxidative Stress in Germinating Grains of Wheat.

PubMed

Filek, Maria; Łabanowska, Maria; Kurdziel, Magdalena; Sieprawska, Apolonia

2017-05-27

These studies concentrate on the possibility of using selenium ions and/or 24-epibrassinolide at non-toxic levels as protectors of wheat plants against zearalenone, which is a common and widespread mycotoxin. Analysis using the UHPLC-MS technique allowed for identification of grains having the stress-tolerant and stress-sensitive wheat genotype. When germinating in the presence of 30 µM of zearalenone, this mycotoxin can accumulate in both grains and hypocotyls germinating from these grains. Selenium ions (10 µM) and 24-epibrassinolide (0.1 µM) introduced together with zearalenone decreased the uptake of zearalenone from about 295 to 200 ng/g and from about 350 to 300 ng/g in the grains of tolerant and sensitive genotypes, respectively. As a consequence, this also resulted in a reduction in the uptake of zearalenone from about 100 to 80 ng/g and from about 155 to 128 ng/g in the hypocotyls from the germinated grains of tolerant and sensitive wheat, respectively. In the mechanism of protection against the zearalenone-induced oxidative stress, the antioxidative enzymes-mainly superoxide dismutase (SOD) and catalase (CAT)-were engaged, especially in the sensitive genotype. Electron paramagnetic resonance (EPR) studies allowed for a description of the chemical character of the long-lived organic radicals formed in biomolecular structures which are able to stabilize electrons released from reactive oxygen species as well as the changes in the status of transition paramagnetic metal ions. The presence of zearalenone drastically decreased the amount of paramagnetic metal ions-mainly Mn(II) and Fe(III)-bonded in the organic matrix. This effect was particularly found in the sensitive genotype, in which these species were found at a smaller level. The protective effect of selenium ions and 24-epibrassinolide originated from their ability to inhibit the destruction of biomolecules by reactive oxygen species. An increased ability to defend biomolecules against zearalenone action was observed for 24-epibrassinolide.

[Induction of free radicals after dietary exposure by mercury contaminated rice and protective effect of coexisting selenium].

PubMed

Ji, Xiu-ling; Cheng, Jin-ping; Wang, Wen-hua; Qu, Li-ya; Zhao, Xiao-xiang; Zhuang, Hui-sheng

2006-10-01

Sprague-Dawley rats were reared by environmental mercury contaminated rice to survey the potential health risk of Wanshan mercury mining area. Electron spin resonance (ESR) was introduced to detect the species and the intensities of free radicals, using spin trap 5,5-dimethyl-1-pyrroline-N-oxide (DMPO). The results showed that the mercury-contaminated rice significantly increased the levels of free radicals and MDA in rat brain at 7 days (p < 0.05). ESR spectrums showed that the principal spin adducts resulted from the trapping of alkyl free radical (alphaH = 22.7 x 10(-4)T +/- 1.6 x 10(-4)T, alphaN = 15.5 x 10(-4)T +/- 0.5 x 10(-4)T), and hydroxyl radical. Levels of free radicals and MDA increased slowly until after 90-day exposure period (83%, 100%). Element correlation analysis showed high correlations of mercury and selenium in the brain of rat fed with Wanshan rice, suggesting that the coexisting selenium in rice exhibited antagonistic effects on both mercury accumulation and toxicity. The slight increases of free radicals in rat brain at 7, 20 and 30-day exposure periods should be related with the scavenger effect of Se.

Combined effect of aerobic interval training and selenium nanoparticles on expression of IL-15 and IL-10/TNF-α ratio in skeletal muscle of 4T1 breast cancer mice with cachexia.

PubMed

Molanouri Shamsi, M; Chekachak, S; Soudi, S; Quinn, L S; Ranjbar, K; Chenari, J; Yazdi, M H; Mahdavi, M

2017-02-01

Cancer cachexia is characterized by inflammation, loss of skeletal muscle and adipose tissue mass, and functional impairment. Oxidative stress and inflammation are believed to regulate pathways controlling skeletal muscle wasting. The aim of this study was to determine the effects of aerobic interval training and the purported antioxidant treatment, selenium nanoparticle supplementation, on expression of IL-15 and inflammatory cytokines in 4T1 breast cancer-bearing mice with cachexia. Selenium nanoparticle supplementation accelerated cachexia symptoms in tumor-bearing mice, while exercise training prevented muscle wasting in tumor-bearing mice. Also, aerobic interval training enhanced the anti-inflammatory indices IL-10/TNF-α ratio and IL-15 expression in skeletal muscle in tumor-bearing mice. However, combining exercise training and antioxidant supplementation prevented cachexia and muscle wasting and additionally decreased tumor volume in 4T1 breast cancer mice. These finding suggested that combining exercise training and antioxidant supplementation could be a strategy for managing tumor volume and preventing cachexia in breast cancer. Copyright © 2016 Elsevier Ltd. All rights reserved.

Ultrastructural changes in the mycelium of Hericium erinaceum (Bull.; Fr.) Pers. under selenium-induced oxidative stress.

PubMed

Ślusarczyk, Joanna; Kuraś, Mieczysław; Malinowska, Eliza; Skalicka-Woźniak, Krystyna; Głowniak, Kazimierz

2014-10-01

In this study we examined the influence of various forms of selenium (organic and inorganic) on the vivacity of Hericium erinaceum mycelium and structural changes and ultrastructure occurring during its development in submerged culture. The mycelium was grown on sodium selenite (Na₂SeO₃), Selol (with 20 and 50 g kg⁻¹ Se, respectively) and a mixture of Na₂SeO₃ and Selol. Samples of the mycelium were collected on day 3 and day 24 of the incubation and viewed under an electron microscope. Selol at concentration 20 g kg⁻¹ did not cause any damage to the cell ultrastructure, but it contributed to the thickening of the cell wall, which implied an influence on polysaccharide production. In the other cases, degradation changes appeared in the protoplasm and the thickness of the cell wall did not increase. The nature of the effect exerted by various sources of selenium in the culture medium on the formation of polysaccharides probably results from the differences in their chemical composition and differences in the toxicity of these compounds towards the cells, but is also connected with the decomposition of the wall surrounding degraded fungal cells. © 2014 Society of Chemical Industry.

REDUCTION OF INORGANIC COMPOUNDS WITH MOLECULAR HYDROGEN BY MICROCOCCUS LACTILYTICUS I.

PubMed Central

Woolfolk, C. A.; Whiteley, H. R.

1962-01-01

Woolfolk, C. A. (University of Washington, Seattle) and H. R. Whiteley. Reduction of inorganic compounds with molecular hydrogen by Micrococcus lactilyticus. I. Stoichiometry with compounds of arsenic, selenium, tellurium, transition and other elements. J. Bacteriol. 84:647–658. 1962.—Extracts of Micrococcus lactilyticus (Veillonella alcalescens) oxidize molecular hydrogen at the expense of certain compounds of arsenic, bismuth, selenium, tellurium, lead, thallium, vanadium, manganese, iron, copper, molybdenum, tungsten, osmium, ruthenium, gold, silver, and uranium, as well as molecular oxygen. Chemical and manometric data indicate that the following reductions are essentially quantitative: arsenate to arsenite, pentavalent and trivalent bismuth to the free element, selenite via elemental selenium to selenide, tellurate and tellurite to tellurium, lead dioxide and manganese dioxide to the divalent state, ferric to ferrous iron, osmium tetroxide to osmate ion, osmium dioxide and trivalent osmium to the metal, uranyl uranium to the tetravalent state, vanadate to the level of vanadyl, and polymolybdate ions to molybdenum blues with an average valence for molybdenum of +5. The results of a study of certain other hydrogenase-containing bacteria with respect to their ability to carry out some of the same reactions are also presented. PMID:14001842

Selenium isotope ratios as indicators of selenium sources and oxyanion reduction

USGS Publications Warehouse

Johnson, T.M.; Herbel, M.J.; Bullen, T.D.; Zawislanski, P.T.

1999-01-01

Selenium stable isotope ratio measurements should serve as indicators of sources and biogeochemical transformations of Se. We report measurements of Se isotope fractionation during selenate reduction, selenite sorption, oxidation of reduced Se in soils, and Se volatilization by algae and soil samples. These results, combined with previous work with Se isotopes, indicate that reduction of soluble oxyanions is the dominant cause of Se isotope fractionation. Accordingly, Se isotope ratios should be useful as indicators of oxyanion reduction, which can transform mobile species to forms that are less mobile and less bioavailable. Additional investigations of Se isotope fractionation are needed to confirm this preliminary assessment. We have developed a new method for measurement of natural Se isotope ratio variation which requires less than 500 ng Se per analysis and yields ??0.2??? precision on 80Se/76Se. A double isotope spike technique corrects for isotopic fractionation during sample preparation and mass spectrometry. The small minimum sample size is important, as Se concentrations are often below 1 ppm in solids and 1 ??g/L in fluids. The Se purification process is rapid and compatible with various sample matrices, including acidic rock or sediment digests.

Selenium isotope ratios as indicators of selenium sources and oxyanion reduction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Johnson, T.M.; Herbel, M.J.; Bullen, T.D.

1999-09-01

Selenium stable isotope ratio measurements should serve as indicators of sources and biogeochemical transformations of Se. The authors report measurements of Se isotope fractionation during selenate reduction, selenite sorption, oxidation of reduced Se in soils, and Se volatilization by algae and soil samples. These results, combined with previous work with Se isotopes, indicate that reduction of soluble oxyanions is the dominant cause of Se isotope fractionation. Accordingly, Se isotope ratios should be useful as indicators of oxyanion reduction, which can transform mobile species to forms that are less mobile and less bioavailable. Additional investigations of Se isotope fractionation are neededmore » to confirm this preliminary assessment. The authors have developed a new method for measurement of natural Se isotope ratio variation which requires less than 500 ng Se per analysis and yields {+-}0.2% precision on {sup 80}Se/{sup 76}Se. A double isotope spike technique corrects for isotopic fractionation during sample preparation and mass spectrometry. The small minimum sample size is important, as Se concentrations are often below 1 ppm in solids and 1 {micro}g/L in fluids. The Se purification process is rapid and compatible with various sample matrices, including acidic rock or sediment digests.« less

Effect of supplementation with organic selenium on mercury status as measured by mercury in pubic hair.

PubMed

Seppänen, K; Kantola, M; Laatikainen, R; Nyyssönen, K; Valkonen, V P; Kaarlöpp, V; Salonen, J T

2000-06-01

The purpose of this study was to evaluate the effect of four months of yeast-based selenium supplementation on selenium and mercury status in subjects with low serum selenium. The study was carried out in Rakvere, Estonia. Pubic hair mercury, serum selenium and blood selenium concentrations in 23 subjects (serum selenium < 90 micrograms/l) were investigated before and after selenium supplementation. Thirteen subjects were randomized into the selenium supplementation group and ten into the placebo group. The selenium supplementation group received daily 100 micrograms of selenomethionine. Selenium supplementation reduced pubic hair mercury level by 34% (p = 0.005) and elevated serum selenium by 73% and blood selenium by 59% in the supplemented group (p < 0.001 for both). The study indicates that mercury accumulation in pubic hair can be reduced by dietary supplementation with small daily amounts of organic selenium in a short range of time.

Speciation of Selenium in Selenium-Enriched Sunflower Oil by High-Performance Liquid Chromatography-Inductively Coupled Plasma Mass Spectrometry/Electrospray-Orbitrap Tandem Mass Spectrometry.

PubMed

Bierla, Katarzyna; Flis-Borsuk, Anna; Suchocki, Piotr; Szpunar, Joanna; Lobinski, Ryszard

2016-06-22

The reaction of sunflower oil with selenite produces a complex mixture of selenitriglycerides with antioxidant and anticancer properties. To obtain insight into the identity and characteristics of the species formed, an analytical approach based on the combination of high-performance liquid chromatography (HPLC) with (78)Se-specific selenium detection by inductively coupled plasma mass spectrometry (ICP MS) and high-resolution (100 000), high mass accuracy (<1 ppm) molecule-specific detection by electrospray-Orbitrap MS(3) was developed. For the first time, a non-aqueous mobile phase gradient was used in reversed-phase HPLC-ICP MS for the separation of a complex mixture of selenospecies and a mathematical correction of the background signal was developed. The identical chromatographic conditions served for the sample introduction into electrospray MS. Two types of samples were analyzed: sunflower oil dissolved in isopropanol and methanol extract of the oil containing 65% selenium. HPLC-ICP MS showed 14 peaks, 11 of which could also be detected in the methanol extract. Isotopic patterns corresponding to molecules with one or two selenium atoms could be attributed by Orbitrap MS at the retention times corresponding to the HPLC-ICP MS peak apexes. Structural data for these species were acquired by MS(2) and MS(3) fragmentation of protonated or sodiated ions using high-energy collisional dissociation (HCD). A total of 11 selenium-containing triglycerol derivatives resulting from the oxidation of one or two double bonds of linoleic acid and analogous derivatives of glycerol-mixed linoleate(s)/oleinate(s) have been identified for the first time. The presence of these species was confirmed by the targeted analysis in the total oil isopropanol solution. Their identification corroborated the predicted elution order in reversed-phase chromatography: LLL (glycerol trilinoleate), LLO (glycerol dilinoleate-oleinate), LOO (glycerol linoleate-dioleinate), OOO (glycerol trioleinate), of which the extrapolation allowed for the prediction of the identity [glycerol dioleinate-stearate (OOS) and glycerol oleinate-distearate (OSS)] of the nonpolar species detected by ICP MS in the oil but not detected by electrospray MS.

Organic selenium supplementation increased selenium concentrations in ewe and newborn lamb blood and in slaughter lamb meat compared to inorganic selenium supplementation.

PubMed

Steen, Arvid; Strøm, Turid; Bernhoft, Aksel

2008-03-31

Selenium is part of the antioxidant defence system in animals and humans. The available selenium concentration in soil is low in many regions of the world. The purpose of this study was to evaluate the effect of organic versus inorganic selenium supplementation on selenium status of ewes, their lambs, and slaughter lambs. Ewes on four organic farms were allocated five or six to 18 pens. The ewes were given either 20 mg/kg inorganic selenium as sodium selenite or organic selenium as selenized nonviable yeast supplementation for the two last months of pregnancy. Stipulated selenium concentrations in the rations were below 0.40 mg/kg dry matter. In addition 20 male lambs were given supplements from November until they were slaughtered in March. Silage, hay, concentrates, and individual ewe blood samples were taken before and after the mineral supplementation period, and blood samples were taken from the newborn lambs. Blood samples from ewes and lambs in the same pens were pooled. Muscle samples were taken from slaughter lambs in March. Selenium concentrations were determined by atomic absorption spectrometry with a hydride generator system. In the ANOVA model, selenium concentration was the continuous response variable, and selenium source and farm were the nominal effect variables. Two-sample t-test was used to compare selenium concentrations in muscle samples from the slaughtered lambs that received either organic or inorganic selenium supplements. In all ewe pens the whole blood selenium concentrations increased during the experimental period. In addition, ewe pens that received organic selenium had significantly higher whole blood selenium concentrations (mean 0.28 microg/g) than ewe pens that received inorganic selenium (mean 0.24 microg/g). Most prominent, however, was the difference in their lambs; whole blood mean selenium concentration in lambs from mothers that received organic selenium (mean 0.27 microg/g) was 30% higher than in lambs from mothers that received inorganic selenium (mean 0.21 microg/g). Slaughter lambs that received organic selenium had 50% higher meat selenium concentrations (mean 0.12 mg/kg wet weight) than lambs that received inorganic selenium (mean 0.08 mg/kg wet weight). Organic selenium supplementation gave higher selenium concentration in ewe and newborn lamb blood and slaughter lamb meat than inorganic selenium supplementation.

Organic selenium supplementation increased selenium concentrations in ewe and newborn lamb blood and in slaughter lamb meat compared to inorganic selenium supplementation

PubMed Central

Steen, Arvid; Strøm, Turid; Bernhoft, Aksel

2008-01-01

Background Selenium is part of the antioxidant defence system in animals and humans. The available selenium concentration in soil is low in many regions of the world. The purpose of this study was to evaluate the effect of organic versus inorganic selenium supplementation on selenium status of ewes, their lambs, and slaughter lambs. Methods Ewes on four organic farms were allocated five or six to 18 pens. The ewes were given either 20 mg/kg inorganic selenium as sodium selenite or organic selenium as selenized nonviable yeast supplementation for the two last months of pregnancy. Stipulated selenium concentrations in the rations were below 0.40 mg/kg dry matter. In addition 20 male lambs were given supplements from November until they were slaughtered in March. Silage, hay, concentrates, and individual ewe blood samples were taken before and after the mineral supplementation period, and blood samples were taken from the newborn lambs. Blood samples from ewes and lambs in the same pens were pooled. Muscle samples were taken from slaughter lambs in March. Selenium concentrations were determined by atomic absorption spectrometry with a hydride generator system. In the ANOVA model, selenium concentration was the continuous response variable, and selenium source and farm were the nominal effect variables. Two-sample t-test was used to compare selenium concentrations in muscle samples from the slaughtered lambs that received either organic or inorganic selenium supplements. Results In all ewe pens the whole blood selenium concentrations increased during the experimental period. In addition, ewe pens that received organic selenium had significantly higher whole blood selenium concentrations (mean 0.28 μg/g) than ewe pens that received inorganic selenium (mean 0.24 μg/g). Most prominent, however, was the difference in their lambs; whole blood mean selenium concentration in lambs from mothers that received organic selenium (mean 0.27 μg/g) was 30% higher than in lambs from mothers that received inorganic selenium (mean 0.21 μg/g). Slaughter lambs that received organic selenium had 50% higher meat selenium concentrations (mean 0.12 mg/kg wet weight) than lambs that received inorganic selenium (mean 0.08 mg/kg wet weight). Conclusion Organic selenium supplementation gave higher selenium concentration in ewe and newborn lamb blood and slaughter lamb meat than inorganic selenium supplementation. PMID:18377659

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

PubMed

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.

Improvement of Heart Redox States Contributes to the Beneficial Effects of Selenium Against Penconazole-Induced Cardiotoxicity in Adult Rats.

PubMed

Chaâbane, Mariem; Tir, Meriem; Hamdi, Safa; Boudawara, Ons; Jamoussi, Kamel; Boudawara, Tahia; Ghorbel, Raoudha Ellouze; Zeghal, Najiba; Soudani, Nejla

2016-02-01

The present study was performed to evaluate the protective effect of selenium (Se) against penconazole (PEN)-induced oxidative stress in the cardiac tissue of adult rats. Male Wistar rats were divided into four groups of six each. The first group represented the controls. For the second group (PEN), no treatment was performed during the first 6 days, and then, the rats received intraperitoneally 67 mg/kg body weight (bw) of PEN every 2 days from day 7 until day 15, the sacrifice day. For the third group (Se + PEN), Se was administered daily through the diet at a dose of 0.5 mg/kg of diet for 15 days. Rats of this group received also every 2 days PEN (67 mg/kg bw) from day 7 until day 15. The fourth group (Se) received daily, through the diet, Se (0.5 mg/Kg of diet) during 15 days. Our results showed that Se reduced significantly the elevated cardiac levels of malondialdehyde and protein carbonyl following PEN treatment, and attenuated DNA fragmentation induced by this fungicide. In addition, Se modulated the alterations of antioxidant status: enzymatic (superoxide dismutase, glutathione peroxidase, and catalase) and nonenzymatic (glutathione and vitamin C) antioxidants in the heart of PEN-treated rats. This trace element was also able to alleviate perturbations of lipid profile. The protective effect of selenium was further evident through the histopathological changes produced by PEN in the heart tissue. Taken together, our results indicated that Se might be beneficial against PEN-induced cardiac oxidative damage in rats.

Association of mercury and selenium with altered glutathione metabolism and oxidative stress in diving ducks from the San Francisco Bay region

USGS Publications Warehouse

Hoffman, D.J.; Ohlendorf, H.M.; Marn, C.M.; Pendleton, G.W.

1998-01-01

Adult male greater scaup (Aythya marila) (GS), surf scoters (Melanitta perspicillata)(SS), and ruddy ducks (Oxyura jamaicensis) (RD) were collected from Suisun Bay and coastal Tomales Bay in the greater San Francisco Bay area to assess exposure to inorganic contaminants. Hepatic selenium (Se) concentrations were highest in GS (geometric mean = 67 ppm, dw) and SS (119 ppm) in Suisun Bay, whereas hepatic mercury (Hg) was highest (19 ppm) in GS and SS from Tomales Bay. Hepatic Se and Hg were lower in RD and did not differ between locations. Hepatic supernatants were assayed for enzymes related to glutathione metabolism and antioxidant activity including: glucose-6-phosphate dehydrogenase (G-6-PDH), glutathione peroxidase (GSH-peroxidase), glutathione reductase (GSSG-reductase), and glutathione-S-transferase (GSH-transferase). GSH-peroxidase activity was higher in SS and RD, and G-6-PDH higher in GS and SS from Suisun Bay than Tomales Bay. GSSG-reductase was higher in SS from Suisun Bay. The ratio of oxidized glutathione (GSSG) to reduced glutathione (GSH) was greater in all species from Tomales Bay. The following significant relationships were found in one or more species with increasing hepatic Hg concentration: lower body, liver and heart weights; decreased hepatic GSH concentration, G-6-PDH and GSH-peroxidase activities; increased ratio of GSSG to GSH, and increased GSSG-reductase activity. With increasing hepatic Se concentration, GSH-peroxidase increased but GSH decreased. It is concluded that measurement of associated enzymes in conjunction with thiol status may be a useful bioindicator to discriminate between Hg and Se effects. Concentrations of mercury and selenium and variable affected have been associated with adverse effects on reproduction and neurological function in experimental studies with mallards.

Gene-specific regulation of hepatic selenoprotein expression by interleukin-6.

PubMed

Martitz, J; Becker, N-P; Renko, K; Stoedter, M; Hybsier, S; Schomburg, L

2015-11-01

Sepsis is a severe inflammatory disease resulting in excessive production of pro-inflammatory cytokines including interleukin-6 (IL-6), causing oxidative stress, tissue damage and organ dysfunction. Health benefits have been observed upon selenium (Se) supplementation in severe sepsis. Selenium is incorporated into selenoproteins implicated in anti-oxidative defence, thyroid hormone metabolism and immunoregulation. Selenium metabolism is controlled by hepatocytes synthesizing and secreting the Se transporter selenoprotein P (SePP). The circulating SePP declines in sepsis causing low serum Se levels. Dysregulation of the hepatic selenoenzyme deiodinase type 1 (DIO1) potentially contributes to the low T3 (thyroid hormone) syndrome observed in severe diseases. We hypothesized that IL-6 affects hepatic selenoprotein biosynthesis directly. Testing human hepatocytes in culture, IL-6 reduced the concentrations of SePP mRNA and secreted SePP in a dose-dependent manner. In parallel, expression of DIO1 declined at the mRNA, protein and enzyme activity level. The effects of IL-6 on glutathione peroxidase (GPX) expression were isozyme-specific; GPX1 remained unaffected, while transcript concentrations of GPX2 increased and those of GPX4 decreased. This pattern of IL-6-dependent effects was mirrored in reporter gene experiments with SePP, DIO1, GPX1, and GPX2 promoter constructs pointing to direct transcriptional effects of IL-6. The redirection of hepatic selenoprotein biosynthesis by IL-6 may represent a central regulatory circuit responsible for the decline of serum Se and low T3 concentrations in sepsis. Accordingly, therapeutic IL-6 targeting may be effective for improving the Se and thyroid hormone status, adjuvant Se supplementation success and survival in sepsis.

Selenium isotopes record extensive marine suboxia during the Great Oxidation Event

PubMed Central

Kipp, Michael A.; Stüeken, Eva E.; Bekker, Andrey; Buick, Roger

2017-01-01

It has been proposed that an “oxygen overshoot” occurred during the early Paleoproterozoic Great Oxidation Event (GOE) in association with the extreme positive carbon isotopic excursion known as the Lomagundi Event. Moreover, it has also been suggested that environmental oxygen levels then crashed to very low levels during the subsequent extremely negative Shunga–Francevillian carbon isotopic anomaly. These redox fluctuations could have profoundly influenced the course of eukaryotic evolution, as eukaryotes have several metabolic processes that are obligately aerobic. Here we investigate the magnitude of these proposed oxygen perturbations using selenium (Se) geochemistry, which is sensitive to redox transitions across suboxic conditions. We find that δ82/78Se values in offshore shales show a positive excursion from 2.32 Ga until 2.1 Ga (mean +1.03 ± 0.67‰). Selenium abundances and Se/TOC (total organic carbon) ratios similarly show a peak during this interval. Together these data suggest that during the GOE there was pervasive suboxia in near-shore environments, allowing nonquantitative Se reduction to drive the residual Se oxyanions isotopically heavy. This implies O2 levels of >0.4 μM in these settings. Unlike in the late Neoproterozoic and Phanerozoic, when negative δ82/78Se values are observed in offshore environments, only a single formation, evidently the shallowest, shows evidence of negative δ82/78Se. This suggests that there was no upwelling of Se oxyanions from an oxic deep-ocean reservoir, which is consistent with previous estimates that the deep ocean remained anoxic throughout the GOE. The abrupt decline in δ82/78Se and Se/TOC values during the subsequent Shunga–Francevillian anomaly indicates a widespread decrease in surface oxygenation. PMID:28096405

Antioxidant and Hepatoprotective Efficiency of Selenium Nanoparticles Against Acetaminophen-Induced Hepatic Damage.

PubMed

Amin, Kamal Adel; Hashem, Khalid Shaban; Alshehri, Fawziah Saleh; Awad, Said T; Hassan, Mohammed S

2017-01-01

Overdoses of acetaminophen (APAP), a famous and widely used drug, may have hepatotoxic effects. Nanoscience is a novel scientific discipline that provides specific tools for medical science problems including using nano trace elements in hepatic diseases. Our study aimed to assess the hepatoprotective role of selenium nanoparticles (Nano-Se) against APAP-induced hepatic injury. Twenty-four male rats were classified into three equal groups: a control group that received 0.9 % NaCl, an APAP-treated group (oral administration), and a group treated with Nano-Se (10-20 nm, intraperitoneal (i.p.) injection) and APAP (oral administration). APAP overdose induced significant elevations in liver function biomarkers, hepatic lipid peroxidation, hepatic catalase, and superoxide dismutase (SOD), decreased the reduced glutathione (GSH) content and glutathione reductase (GR) activity, and stimulated significant DNA damage in hepatocytes, compared to control rats. Nano-Se administration improved the hepatic antioxidant protection mechanism and decreased cellular sensitivity to DNA fragmentation. Nano-Se exhibits a protective effect against APAP-induced hepatotoxicity through improved liver function and oxidative stress mediated by catalase, SOD, and GSH and decreases hepatic DNA fragmentation, a hepatic biomarker of cell death. Nano-Se could be a novel hepatoprotective strategy to inhibit oxidative stress.

Effects of vitamin E and organic selenium on oxidative stability of omega-3 enriched dark chicken meat during cooking.

PubMed

Perez, T I; Zuidhof, M J; Renema, R A; Curtis, J M; Ren, Y; Betti, M

2010-03-01

The influence of vitamin E and selenomethionine (SeMet) on lipid oxidation in frozen-raw and cooked omega-3 enriched dark chicken meat was evaluated. Feed was supplemented with 2 levels of vitamin E (250 and 50 IU/kg of feed) and selenium (0.1 mg of sodium selenite/kg of feed and 0.3 mg of SeMet/kg of feed). An extruded linseed product was used as the alpha-linolenic acid source. Fatty acid (FA) profile, oxysterols, and thiobarbituric reactive acid substances (TBARs) were analyzed in frozen-raw, boiled, pan-fried, and roasted meat. After 6 mo of storage, oxysterols in frozen-raw meat remained stable with either high or low levels of dietary antioxidants. During cooking, high levels of vitamin E reduced oxysterol formation, whereas high levels of SeMet were inconsistent and even increased oxysterols during roasting. TBARs in frozen-raw meat stored for 6 mo were inhibited by high levels of either antioxidant. Conversely, no protective effect during cooking was observed at this time of storage. After 12 mo at -30 degrees C no antioxidant protection was observed.

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

PubMed

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 apoptosis, oxidative stress, and calcium accumulation through TRPM2 and TRPV1 channels in the hippocampus neurons of aged rats. The TRPM2 channel is activated by ADP-ribose and oxidative stress, although it is inhibited by ACA. The TRPV1 channel is activated by oxidative stress and capsaicin, and it is blocked by capsazepine (CPZ). The beta-amyloid plaque induces oxidative stress in hippocampus. SCOP can result in augmented ROS release in hippocampal neurons, leading to Ca 2+ uptake through TRPM2 and TRPV1 channels. Mitochondria were reported to accumulate Ca 2+ provided that intracellular Ca 2+ rises, thereby leading to the depolarization of mitochondrial membranes and release of apoptosis-inducing factors such as caspase 3 and caspase 9. Se reduced TRPM2 and TRPV1 channel activation through the modulation of aging oxidative reactions and Se-dependent glutathione peroxidase (GSH-Px) antioxidant pathways.

Speciation and weathering of selenium in upper cretaceous chalk and shale from South Dakota and Wyoming, USA

NASA Astrophysics Data System (ADS)

Kulp, Thomas R.; Pratt, Lisa M.

2004-09-01

In geologic materials, petroleum, and the environment, selenium occurs in various oxidation states (VI, IV, 0, -II), mineralized forms, and organo-Se complexes. Each of these forms is characterized by specific chemical and biochemical properties that control the element's solubility, toxicity, and environmental behavior. The organic rich chalks and shales of the Upper Cretaceous Niobrara Formation and the Pierre Shale in South Dakota and Wyoming are bentoniferous stratigraphic intervals characterized by anomalously high concentrations of naturally occurring Se. Numerous environmental problems have been associated with Se derived from these geological units, including the development of seleniferous soils and vegetation that are toxic to livestock and the contamination of drinking water supplies by Se mobilized in groundwater. This study describes a sequential extraction protocol followed by speciation treatments and quantitative analysis by Hydride Generation-Atomic Absorption Spectroscopy. This protocol was utilized to investigate the geochemical forms and the oxidation states in which Se occurs in these geologic units. Organic Se and di-selenide minerals are the predominant forms of Se present in the chalks, shales, and bentonites, but distinctive variations in these forms were observed between different sample types. Chalks contain significantly greater proportions of Se in the form of di-selenide minerals (including Se associated with pyrite) than the shales where base-soluble, humic, organo-Se complexes are more prevalent. A comparison between unweathered samples collected from lithologic drill cores and weathered samples collected from outcrop suggest that the humic, organic-Se compounds in shale are formed during oxidative weathering and that Se oxidized by weathering is more likely to be retained by shale than by chalk. Selenium enrichment in bentonites is inferred to result from secondary processes including the adsorption of Se mobilized by groundwater from surrounding organic rich sediments to clay mineral and iron hydroxide surfaces, as well as microbial reduction of Se within the bentonitic intervals. Distinct differences are inferred for the biogeochemical pathways that affected sedimentary Se sequestration during periods of chalk accumulation compared to shale deposition in the Cretaceous seaway. Mineralogy of sediment and the nature of the organic matter associated with each of these rock types have important implications for the environmental chemistry and release of Se to the environment during weathering.

Distribution and mode of occurrence of selenium in US coals

USGS Publications Warehouse

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.

Maternal-fetal transfer of selenium in the mouse.

PubMed

Burk, Raymond F; Olson, Gary E; Hill, Kristina E; Winfrey, Virginia P; Motley, Amy K; Kurokawa, Suguru

2013-08-01

Selenoprotein P (Sepp1) is taken up by receptor-mediated endocytosis for its selenium. The other extracellular selenoprotein, glutathione peroxidase-3 (Gpx3), has not been shown to transport selenium. Mice with genetic alterations of Sepp1, the Sepp1 receptors apolipoprotein E receptor-2 (apoER2) and megalin, and Gpx3 were used to investigate maternal-fetal selenium transfer. Immunocytochemistry (ICC) showed receptor-independent uptake of Sepp1 and Gpx3 in the same vesicles of d-13 visceral yolk sac cells, suggesting uptake by pinocytosis. ICC also showed apoER2-mediated uptake of maternal Sepp1 in the d-18 placenta. Thus, two selenoprotein-dependent maternal-fetal selenium transfer mechanisms were identified. Selenium was quantified in d-18 fetuses with the mechanisms disrupted. Maternal Sepp1 deletion, which lowers maternal whole-body selenium, decreased fetal selenium under selenium-adequate conditions but deletion of fetal apoER2 did not. Fetal apoER2 deletion did decrease fetal selenium, by 51%, under selenium-deficient conditions, verifying function of the placental Sepp1-apoER2 mechanism. Maternal Gpx3 deletion decreased fetal selenium, by 13%, but only under selenium-deficient conditions. These findings indicate that the selenoprotein uptake mechanisms ensure selenium transfer to the fetus under selenium-deficient conditions. The failure of their disruptions (apoER2 deletion, Gpx3 deletion) to affect fetal selenium under selenium-adequate conditions indicates the existence of an additional maternal-fetal selenium transfer mechanism.

Selenium bioaccessibility and speciation in biofortified Pleurotus mushrooms grown on selenium-rich agricultural residues.

PubMed

Bhatia, Poonam; Aureli, Federica; D'Amato, Marilena; Prakash, Ranjana; Cameotra, Swaranjit Singh; Nagaraja, Tejo Prakash; Cubadda, Francesco

2013-09-01

Cultivation of saprophytic fungi on selenium-rich substrates can be an effective means to produce selenium-fortified food. Pleurotus florida, an edible species of oyster mushrooms, was grown on wheat straw from the seleniferous belt of Punjab (India) and its potential to mobilize and accumulate selenium from the growth substrate was studied. Selenium concentration in biofortified mushrooms was 800 times higher compared with control samples grown on wheat straw from non selenium-rich areas (141 vs 0.17 μg Se g(-1) dry weight). Seventy-five percent of the selenium was extracted after in vitro simulated gastrointestinal digestion and investigation of the selenium molecular fractions by size exclusion HPLC-ICP-MS revealed that proteins and any other high molecular weight selenium-containing molecule were hydrolyzed to peptides and low molecular weight selenocompounds. Analysis of the gastrointestinal hydrolysates by anion exchange HPLC-ICP-MS showed that the bioaccessible selenium was mainly present as selenomethionine, a good bioavailable source of selenium, which accounted for 73% of the sum of the detected species. This study demonstrates the feasibility of producing selenium-biofortified edible mushrooms using selenium-rich agricultural by-products as growth substrates. The proposed approach can be used to evaluate whether selenium-contaminated plant waste materials harvested from high-selenium areas may be used to produce selenium-biofortified edible mushrooms based on the concentration, bioaccessibility and speciation of selenium in the mushrooms. Copyright © 2013 Elsevier Ltd. All rights reserved.

Bioavailability of particle-associated Se to the bivalve Potamocorbula amurensis

USGS Publications Warehouse

Schlekat, C.E.; Dowdle, P.R.; Lee, B.-G.; Luoma, S.N.; Oremland, R.S.

2000-01-01

Elemental selenium, Se(0), is a prevalent chemical form in sediments, but little is known about its bioavailability. We evaluated the bioavailability of two forms of Se(0) by generating radioisotopic 75Se(0) through bacterial dissimilatory reduction of 75SeO32- by pure bacterial cultures (SES) and by an anaerobic sediment microbial consortium (SED). A third form was generated by reducing 75SeO32- with ascorbic acid (AA). Speciation determinations showed that AA and SES were >90% Se(0), but SED showed a mixture of Se(0), selenoanions, and a residual fraction. Pulse-chase techniques were used to measure assimilation efficiencies (AE) of these particulate Se forms by the bivalve Potamocorbula amurensis. Mean AE values were 3 ?? 2% for AA, 7 ?? 1% for SES, and 28 ?? 15% for SED, showing that the bioavailability of reduced, particle-associated Se is dependent upon its origin. To determine if oxidative microbial processes increased Se transfer, SES 75Se(0) was incubated with an aerobic sediment microbial consortium. After 113 d of incubation, 36% of SES Se(0) was oxidized to SeO32-. Assimilation of total particulate Se was unaffected however (mean AE = 5.5%). The mean AE from the diatom Phaeodactylum tricornutum was 58 ?? 8%, verifying the importance of Se associated with biogenic particles. Speciation and AE results from SED suggest that selenoanion reduction in wetlands and estuaries produces biologically available reduced selenium.Elemental selenium, Se(0), is a prevalent chemical form in sediments, but little is known about its bioavailability. We evaluated the bioavailability of two forms of Se(0) by generating radioisotopic 75Se(0) through bacterial dissimilatory reduction of 75SeO32- by pure bacterial cultures (SES) and by an anaerobic sediment microbial consortium (SED). A third form was generated by reducing 75SeO32 with ascorbic acid (AA). Speciation determinations showed that AA and SES were > 90% Se(0), but SED showed a mixture of Se(0), selenoanions, and a residual fraction. Pulse-chase techniques were used to measure assimilation efficiencies (AE) of these particulate Se forms by the bivalve Potamocorbula amurensis. Mean AE values were 3 ?? 2% for AA, 7 ?? 1% for SES, and 28 ?? 15% for SED, showing that the bioavailability of reduced, particle-associated Se is dependent upon its origin. To determine if oxidative microbial processes increased Se transfer, SES 75Se(0) was incubated with an aerobic sediment microbial consortium. After 113 d of incubation, 36% of SES Se(0) was oxidized to SeO32-. Assimilation of total particulate Se was unaffected however (mean AE = 5.5%). The mean AE from the diatom Phaeodactylum tricornutum was 58 ?? 8%, verifying the importance of Se associated with biogenic particles. Speciation and AE results from SED suggest that selenoanion reduction in wetlands and estuaries produces biologically available reduced selenium.

Selenium protein identification and profiling by mass spectrometry: A tool to assess progression of cardiomyopathy in a whale model.

PubMed

Bryan, Colleen E; Bossart, Gregory D; Christopher, Steven J; Davis, W Clay; Kilpatrick, Lisa E; McFee, Wayne E; O'Brien, Terrence X

2017-12-01

Non-ischemic cardiomyopathy is a leading cause of congestive heart failure and sudden cardiac death in humans and in some cases the etiology of cardiomyopathy can include the downstream effects of an essential element deficiency. Of all mammal species, pygmy sperm whales (Kogia breviceps) present the greatest known prevalence of cardiomyopathy with more than half of examined individuals indicating the presence of cardiomyopathy from gross and histo-pathology. Several factors such as genetics, infectious agents, contaminants, biotoxins, and inappropriate dietary intake (vitamins, selenium, mercury, and pro-oxidants), may contribute to the development of idiopathic cardiomyopathy in K. breviceps. Due to the important role Se can play in antioxidant biochemistry and protein formation, Se protein presence and relative abundance were explored in cardiomyopathy related cases. Selenium proteins were separated and detected by multi-dimension liquid chromatography inductively coupled plasma mass spectrometry (LC-ICP-MS), Se protein identification was performed by liquid chromatography electrospray tandem mass spectrometry (LC-ESI-MS/MS), and Se protein profiles were examined in liver (n=30) and heart tissue (n=5) by SEC/UV/ICP-MS detection. Data collected on selenium proteins was evaluated in the context of individual animal trace element concentration, life history, and histological information. Selenium containing protein peak profiles varied in presence and intensity between animals with no pathological findings of cardiomyopathy and animals exhibiting evidence of cardiomyopathy. In particular, one class of proteins, metallothioneins, was found to be associated with Se and was in greater abundance in animals with cardiomyopathy than those with no pathological findings. Profiling Se species with SEC/ICP-MS proved to be a useful tool to identify Se protein pattern differences between heart disease stages in K. breviceps and an approach similar to this may be applied to other species to study Se protein associations with cardiomyopathy. Published by Elsevier GmbH.

Selenium and its relationship with selenoprotein P and glutathione peroxidase in children and adolescents with Hashimoto's thyroiditis and hypothyroidism.

PubMed

Nourbakhsh, Mitra; Ahmadpour, Fatemeh; Chahardoli, Behnam; Malekpour-Dehkordi, Zahra; Nourbakhsh, Mona; Hosseini-Fard, Seyed Reza; Doustimotlagh, Amirhossein; Golestani, Abolfazl; Razzaghy-Azar, Maryam

2016-03-01

The essential trace element selenium (Se) is required for thyroid hormone synthesis and metabolism. Selenoproteins contain selenocysteine and are responsible for biological functions of selenium. Glutathione peroxidase (GPx) is one of the major selenoproteins which protects the thyroid cells from oxidative damage. Selenoprotein P (SePP) is considered as the plasma selenium transporter to tissues. The aim of this study was to evaluate serum Se and SePP levels, and GPx activity in erythrocytes of children and adolescents with treated Hashimoto's thyroiditis, hypothyroidism, and normal subjects. Blood samples were collected from 32 patients with Hashimoto's thyroiditis, 20 with hypothyroidism, and 25 matched normal subjects. All the patients were under treatment with levothyroxine and at the time of analysis all of the thyroid function tests were normal. GPx enzyme activity was measured by spectrophotometry at 340 nm. Serum selenium levels were measured by high-resolution continuum source graphite furnace atomic absorption. SePP, TPOAb (anti-thyroid peroxidase antibody), and TgAb (anti-thyroglobulin antibody) were determined by ELISA kits. T4, T3, T3 uptake and TSH were also measured. Neither GPx activity nor SePP levels were significantly different in patients with Hashimoto's thyroiditis or hypothyroidism compared to normal subjects. Although GPx and SePP were both lower in patients with hypothyroidism compared to those with Hashimoto's thyroiditis and normal subjects but the difference was not significant. Serum Se levels also did not differ significantly in patients and normal subjects. We did not find any correlation between GPx or SePP with TPOAb or TgAb but SePP was significantly correlated with Se. Results show that in patients with Hashimoto's thyroiditis or hypothyroidism who have been under treatment with levothyroxine and have normal thyroid function tests, the GPx, SePP and Se levels are not significantly different. Copyright © 2015 Elsevier GmbH. All rights reserved.

Selenium Reduces Early Signs of Tumor Necrosis Factor Alpha-Induced Meniscal Tissue Degradation.

PubMed

Häfelein, Klaus; Preuße-Prange, Andrea; Behrendt, Peter; Kurz, Bodo

2017-05-01

Meniscal integrity is a prerequisite for sustained knee joint health and prevention of meniscal degeneration is a main research goal. Cartilage-protective effects of selenium have been described, but little is known about the impact on the meniscus. We therefore investigated the influence of sodium selenite on meniscal explants under tumor necrosis factor-alpha (TNFα)-stimulated proinflammatory conditions. Meniscal explant disks (3 mm diameter × 1 mm thickness) were isolated from 2-year-old cattle and incubated with TNFα (10 ng/ml) and sodium selenite (low dose, LoD 6.7 ng/ml as being found in Insulin-Transferrin-Selenium medium supplements, ITS; medium-dose, MeD 40 ng/ml described as physiological synovial concentration; high dose, HiD 100 ng/ml described as optimal serum concentration). After 3 days of culture glycosaminoglycan (GAG) release (DMMB assay), nitric oxide (NO) production (Griess assay), gene expression of matrix-degrading enzymes (quantitative RT-PCR), and apoptosis rate were determined. TNFα led to a significant raise of GAG release and NO production. LoD and MeD selenite significantly reduced the TNFα-induced GAG release (by 83, 55 %, respectively), NO production (by 59, 40 %, respectively), and apoptosis (by 68, 39 %, respectively). LoD and MeD selenite showed a tendency to reduce the TNFα-mediated increase of inducible NO-synthase (iNOS) levels, LoD selenite furthermore matrix metalloproteinase (MMP)-3 transcription levels and a disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS)-4 levels. LoD and less pronounced MeD selenite show a substantial impact on the early meniscal inflammatory response. To our knowledge this is the first study showing the protective influence of selenium on meniscal tissue maintenance. To understand the superior potency of low-dose selenium on molecular level future studies are needed.

Selenium Distribution and Fractionation in a Managed Urban Watershed

NASA Astrophysics Data System (ADS)

Papelis, C.; Boettcher, T. M.; Harris-Burr, R. D.

2006-12-01

Metals, and metalloids, are common contaminants of concern in arid and semi-arid watersheds in the Southwestern U.S. Because of the dramatic population growth in this part of the U.S., the potential for contamination of urban watersheds has also increased over the last few decades. Streams in urban watersheds receive storm water, urban runoff, shallow groundwater, and treated wastewater. In addition, urban watersheds are often heavily managed to mitigate flood events and sediment-related impacts. Clearly, sediment transport can have a profound effect on the water quality of affected bodies of water, not only by affecting water clarity, but also by facilitating the transport of chemical constituents, as well as microbiological components. The Las Vegas Wash (Wash) is the lowest point in the Las Vegas Valley Watershed and receives storm water, urban runoff, and treated wastewater from the entire Las Vegas Valley. To minimize erosion, caused by the dramatic wastewater flow increase during the last few decades, several erosion control structures are being built. In addition, wetlands being constructed in the Wash area receive most of the water from the Wash. The construction of these ponds has the potential to alter the distribution of metals and metalloids in bodies of water used by wildlife. An element of particular concern is selenium, a metalloid commonly found at elevated concentrations in soils of the U.S. Southwest. To assess the potential adverse impact on water quality, sediment samples were collected along the Wash, upstream and downstream of erosion control structures, and around current and future constructed wetlands. The sediments were characterized by particle size distribution, specific surface area, mineralogical composition, organic carbon content, and scanning electron microscopy. The total selenium, as well as the percentages associated with exchangeable, organic, carbonate, and oxide sediment fractions were determined. The distribution of selenium as a function of sediment properties and the potential of selenium availability in this environment will be discussed.

Comparative study of selenium and selenium nanoparticles with reference to acute toxicity, biochemical attributes, and histopathological response in fish.

PubMed

Kumar, Neeraj; Krishnani, Kishore Kumar; Singh, Narendra Pratap

2018-03-01

Recent studies have demonstrated that selenium (Se) and selenium nanoparticles (Se-NPs) exhibited toxicity at a higher concentration. The lethal concentration of Se and Se-NPs was estimated as 5.29 and 3.97 mg/L at 96 h in Pangasius hypophthalmus. However, the effect of different definite concentration of Se (4.5, 5.0, 5.5, and 6.0 mg/L) and Se-NPs (2.5, 3.0, 3.5, and 4.0 mg/L) was decided for acute experiment. Selenium and Se-NPs alter the biochemical attributes such as anti-oxidative status [catalase (CAT), superoxide dismutase (SOD), and glutathione-S-transferase (GST) activities], neurotransmitter enzyme, cellular metabolic enzymes, stress marker, and histopathology of P. hypophthalmus in a dose- and time-dependent manner. CAT, SOD, and GST were significantly elevated (p < 0.01) when exposed to Se and Se-NPs, and similarly, a neurotransmitter enzyme (acetylcholine esterase (AChE)) was significantly inhibited in a time- and dose-dependent manner. Further, aspartate aminotransferase, alanine aminotransferase, lactate dehydrogenase, and malate hydrogenase were noticeably (p < 0.01) affected by Se and Se-NPs from higher concentration to lower concentration. Stress markers such as cortisol and HSP 70 were drastically enhanced by exposure to Se and Se-NPs. All the cellular metabolic and stress marker parameters were elevated which might be due to hyperaccumulation of Se and Se-NPs in the vital organ and target tissues. The histopathology of liver and gill was also altered such as large vacuole, cloudy swelling, focal necrosis, interstitial edema, necrosis in liver, and thickening of primary lamellae epithelium and curling of secondary lamellae due to Se and Se-NP exposure. The study suggested that essential trace element in both forms (inorganic and nano) at higher concentration in acute exposure of Se and Se-NPs led to pronounced deleterious alteration on histopathology and cellular and metabolic activities of P. hypophthalmus.

Speciation of organic and inorganic selenium in selenium-enriched rice by graphite furnace atomic absorption spectrometry after cloud point extraction.

PubMed

Sun, Mei; Liu, Guijian; Wu, Qianghua

2013-11-01

A new method was developed for the determination of organic and inorganic selenium in selenium-enriched rice by graphite furnace atomic absorption spectrometry detection after cloud point extraction. Effective separation of organic and inorganic selenium in selenium-enriched rice was achieved by sequentially extracting with water and cyclohexane. Under the optimised conditions, the limit of detection (LOD) was 0.08 μg L(-1), the relative standard deviation (RSD) was 2.1% (c=10.0 μg L(-1), n=11), and the enrichment factor for selenium was 82. Recoveries of inorganic selenium in the selenium-enriched rice samples were between 90.3% and 106.0%. The proposed method was successfully applied for the determination of organic and inorganic selenium as well as total selenium in selenium-enriched rice. Copyright © 2013 Elsevier Ltd. All rights reserved.

Maternal-fetal transfer of selenium in the mouse

PubMed Central

Burk, Raymond F.; Olson, Gary E.; Hill, Kristina E.; Winfrey, Virginia P.; Motley, Amy K.; Kurokawa, Suguru

2013-01-01

Selenoprotein P (Sepp1) is taken up by receptor-mediated endocytosis for its selenium. The other extracellular selenoprotein, glutathione peroxidase-3 (Gpx3), has not been shown to transport selenium. Mice with genetic alterations of Sepp1, the Sepp1 receptors apolipoprotein E receptor-2 (apoER2) and megalin, and Gpx3 were used to investigate maternal-fetal selenium transfer. Immunocytochemistry (ICC) showed receptor-independent uptake of Sepp1 and Gpx3 in the same vesicles of d-13 visceral yolk sac cells, suggesting uptake by pinocytosis. ICC also showed apoER2-mediated uptake of maternal Sepp1 in the d-18 placenta. Thus, two selenoprotein-dependent maternal-fetal selenium transfer mechanisms were identified. Selenium was quantified in d-18 fetuses with the mechanisms disrupted. Maternal Sepp1 deletion, which lowers maternal whole-body selenium, decreased fetal selenium under selenium-adequate conditions but deletion of fetal apoER2 did not. Fetal apoER2 deletion did decrease fetal selenium, by 51%, under selenium-deficient conditions, verifying function of the placental Sepp1-apoER2 mechanism. Maternal Gpx3 deletion decreased fetal selenium, by 13%, but only under selenium-deficient conditions. These findings indicate that the selenoprotein uptake mechanisms ensure selenium transfer to the fetus under selenium-deficient conditions. The failure of their disruptions (apoER2 deletion, Gpx3 deletion) to affect fetal selenium under selenium-adequate conditions indicates the existence of an additional maternal-fetal selenium transfer mechanism.—Burk, R. F., Olson, G. E., Hill, K. E., Winfrey, V. P., Motley, A. K., and Kurokawa, S. Maternal-fetal transfer of selenium in the mouse. PMID:23651543

Production of Selenoprotein P (Sepp1) by Hepatocytes Is Central to Selenium Homeostasis*

PubMed Central

Hill, Kristina E.; Wu, Sen; Motley, Amy K.; Stevenson, Teri D.; Winfrey, Virginia P.; Capecchi, Mario R.; Atkins, John F.; Burk, Raymond F.

2012-01-01

Sepp1 is a widely expressed extracellular protein that in humans and mice contains 10 selenocysteine residues in its primary structure. Extra-hepatic tissues take up plasma Sepp1 for its selenium via apolipoprotein E receptor-2 (apoER2)-mediated endocytosis. The role of Sepp1 in the transport of selenium from liver, a rich source of the element, to peripheral tissues was studied using mice with selective deletion of Sepp1 in hepatocytes (Sepp1c/c/alb-cre+/− mice). Deletion of Sepp1 in hepatocytes lowered plasma Sepp1 concentration to 10% of that in Sepp1c/c mice (controls) and increased urinary selenium excretion, decreasing whole-body and tissue selenium concentrations. Under selenium-deficient conditions, Sepp1c/c/alb-cre+/− mice accumulated selenium in the liver at the expense of extra-hepatic tissues, severely worsening clinical manifestations of dietary selenium deficiency. These findings are consistent with there being competition for metabolically available hepatocyte selenium between the synthesis of selenoproteins and the synthesis of selenium excretory metabolites. In addition, selenium deficiency down-regulated the mRNA of the most abundant hepatic selenoprotein, glutathione peroxidase-1 (Gpx1), to 15% of the selenium-replete value, while reducing Sepp1 mRNA, the most abundant hepatic selenoprotein mRNA, only to 61%. This strongly suggests that Sepp1 synthesis is favored in the liver over Gpx1 synthesis when selenium supply is limited, directing hepatocyte selenium to peripheral tissues in selenium deficiency. We conclude that production of Sepp1 by hepatocytes is central to selenium homeostasis in the organism because it promotes retention of selenium in the body and effects selenium distribution from the liver to extra-hepatic tissues, especially under selenium-deficient conditions. PMID:23038251

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

PubMed

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 biotechnological advances in the management of these selenium-laden wastewaters. Copyright © 2016 Elsevier Inc. All rights reserved.

Bio-transformation of selenium in Se-enriched bacterial strains of Lactobacillus casei.

PubMed

Kurek, Eliza; Ruszczyńska, Anna; Wojciechowski, Marcin; Łuciuk, Anna; Michalska-Kacymirow, Magdalena; Motyl, Ilona; Bulska, Ewa

Selenium is an element of very great importance for the proper functioning of the human body, mainly due to its antioxidant properties. Selenium exhibits a preventive effect in the case of cardiovascular disease, the immune system, male infertility and inhibits the toxic action of other agents. Selenium is important for Hashimoto's disease. Intake of selenium in the diet slows the aging process. The biological and toxicological effects of selenium strongly depend on its chemical form. Some organisms for example: plant, yeast, are capable of metabolizing low bioavailable selenium compounds (inorganic selenium) into its high bioavailable forms (organic selenium). The aim of this study was to investigate the bio-transformation of selenium by Lactobacillus bacteria towards the characterisation of selenium metabolites. The speciation of selenium was evaluated by high performance liquid chromatography with inductively coupled plasma mass spectrometry detector. The extraction of selenium species from lyophilized bacteria was executed with water, the mixture of lipase and protease, as well as lisozyme and sodium dodecyl sulphate. All investigated bacteria strains cultivated in the presence of Na2SeO3 effectively uptake selenium. Surprisingly, none of the applied extraction media exhibited a strong power to release the majority of the uptaken selenium compounds. Thus a maximum of 10% of the selenium was extracted from bacteria exposed to the enzymes. However, it was found that Lactobacillus bacteria are able to metabolize inorganic ions of selenium (IV) into Se-methionine, Se-methyloselenocysteine and other unidentified forms. The study confirmed the ability of probiotic bacteria to biotransform inorganic selenium into its organic derivatives. Therefore, Se-enriched bacteria can be considered as an addition to the functional food. selenium speciation, extraction procedure, Lactobacillus casei bacteria, Lactic acid bacteria (LAB), HPLC ICP-MS, functional food.

Stunting, selenium deficiency and anemia are associated with poor cognitive performance in preschool children from rural Ethiopia.

PubMed

Gashu, Dawd; Stoecker, Barbara J; Bougma, Karim; Adish, Abdulaziz; Haki, Gulelat D; Marquis, Grace S

2016-04-12

Anthropometric characteristics and iron status affect cognitive performance in children. In addition, selenium can influence cognitive outcomes; protection of the brain from oxidative stress and its role in thyroid hormone metabolism are putative mechanisms. To investigate their association with cognitive performance, anthropometric indicators, iron biomarkers, and serum selenium of children (n = 541) of 54-60mo of age from rural Ethiopia were assessed. Cognitive assessment was conducted with the administration of two reasoning subtests of the Wechsler Preschool and Primary Scale of Intelligence and the school readiness test. Stunting was found in 41.4 % of children, 28.7 % were underweight, and 6.3 % were wasted. The mean score of stunted children was lower than that of non-stunted children on non-verbal reasoning (7.0 ± 3.2vs7.9 ± 3.1; p = 0.01) and the school readiness tests (4.3 ± 2.2 vs 3.3 ± 2.1; p < 0.001). Compared to non-anemic children, anemic children had lower score for the verbal reasoning test (9.5 ± 1.7 vs 8.9 ± 2.2; p = 0.02). However, except for hemoglobin, none of the iron biomarkers had significant associations with the cognitive score of the study children (p > 0.05). Selenium deficient children had lower scores on all cognitive tests than normal children (p < 0.05). The present study finding linking chronic undernutrition and micronutrient deficiency to cognitive deficits suggests the need for designing effective intervention programmes to control for protein energy malnutrition and micronutrient deficiency and address cognitive development in children.

The curative and antioxidative efficiency of ivermectin and ivermectin + vitamin E-selenium treatment on canine Sarcoptes scabiei infestation.

PubMed

Behera, Suvendu Kumar; Dimri, Umesh; Singh, Shanker Kumar; Mohanta, Ranjan Kumar

2011-04-01

The objective of the present study was to investigate the curative and antioxidative efficacy of ivermectin and ivermectin + vitamin E-selenium, and the influence of these agents on oxidative stress parameters in canines infested by Sarcoptes scabiei. Twenty two sarcoptic mites infested dogs and nine healthy dogs of 6 months to 2 years of age were divided into three groups. Group I comprised of healthy dogs (n=9) whereas animals in group II (n=11) and III (n=11) were positive for scabies. Group II animals were treated with only 1% ivermectin @ 0.2 mg/kg SC whereas group III were additionally treated with Vitamin E and selenium (tocopherol 50 mg + Se 1.5 mg/ml) @ 0.5 ml/20 kg IM at weekly intervals for three times. Blood samples were collected on day 0 and 28 post therapy. The values for hemato-biochemical parameters and activities of antioxidant enzymes were significantly decreased (P<0.05) whereas level of lipid peroxidation was significantly increased in all the infested dogs in comparison to the healthy dogs on day 0 which approached normalcy by day 28 post therapy. The dogs of group III showed better clinical recovery in comparison to group II at the end of therapy. Thus, administration of vitamin E and selenium in addition to standard therapy can alleviate these alterations hastening the clinical recovery of diseased dogs and can be recommended as an adjunct therapy with miticides for canine sarcoptic mange. © Springer Science+Business Media B.V. 2011

Determination of the oxidation states of metals and metalloids: An analytical review

NASA Astrophysics Data System (ADS)

Vodyanitskii, Yu. N.

2013-12-01

The hazard of many heavy metals/metalloids in the soil depends on their oxidation state. The problem of determining the oxidation state has been solved due to the use of synchrotron radiation methods with the analysis of the X-ray absorption near-edge structure (XANES). The determination of the oxidation state is of special importance for some hazardous heavy elements (arsenic, antimony, selenium, chromium, uranium, and vanadium). The mobility and hazard of each of these elements depend on its oxidation state. The mobilities are higher at lower oxidation states of As, Cr, V, and Se and at higher oxidation states of Sb and U. The determination of the oxidation state of arsenic has allowed revealing its fixation features in the rhizosphere of hydrophytes. The known oxidation states of chromium and uranium are used for the retention of these elements on geochemical barriers. Different oxidation states have been established for vanadium displacing iron in goethite. The determination of the oxidation state of manganese in the rhizosphere and the photosynthetic apparatus of plants is of special importance for agricultural chemists.

Percutaneous absorption of selenium sulfide

DOE Office of Scientific and Technical Information (OSTI.GOV)

Farley, J.; Skelly, E.M.; Weber, C.B.

1986-01-01

The purpose of this study was to determine selenium levels in the urine of Tinea patients before and after overnight application of a 2.5% selenium sulfide lotion. Selenium was measured by atomic absorption spectroscopy (AAS). Hydride generation and carbon rod atomization were studied. It was concluded from this study that selenium is absorbed through intact skin. Selenium is then excreted, at least partially, in urine, for at least a week following treatment. The data show that absorption and excretion of selenium vary on an individual basis. Selenium levels in urine following a single application of selenium sulfide lotion do notmore » indicate that toxic amounts of selenium are being absorbed. Repeated treatments with SeS/sub 2/ result in selenium concentrations in urine which are significantly higher than normal. Significant matrix effects are observed in the carbon rod atomization of urine samples for selenium determinations, even in the presence of a matrix modifier such as nickel. The method of standard additions is required to obtain accurate results in the direct determination of selenium in urine by carbon rod AAS.« less

Stability of sonicated aqueous suspensions of phospholipids under air.

PubMed

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.

Selenium Administration Alleviates Toxicity of Chromium(VI) in the Chicken Brain.

PubMed

Hao, Pan; Zhu, Yiran; Wang, Shenghua; Wan, Huiyu; Chen, Peng; Wang, Yang; Cheng, Ziqiang; Liu, Yongxia; Liu, Jianzhu

2017-07-01

Selenium (Se) can play a protective role against heavy metal toxicity. This experiment aims to evaluate the effect of Se supplementation at different doses on the chicken brains. Oxidative stress was induced in the chicken brains by chromium(VI). A total of 105 Hyland brown male chickens were randomly divided into seven groups, including the control group, poisoned group [6%LD 50 K 2 Cr 2 O 7 body weight (B.W.)], and detoxification groups K 2 Cr 2 O 7 (6%LD 50 ) + Se (0.31, 0.63, 1.25, 2.50, and 5.00 Na 2 SeO 3 mg/kg B.W.) orally in water for 42 days. The chickens were detected by the activities of mitochondrial membrane potential, 2'-benzoyloxycinnamaldehyde, superoxide dismutase (SOD), malondialdehyde (MDA), glutathione (GSH), and Ca 2+ -ATPase. Cr(VI) administration caused histopathological damage. In addition, changes in oxidative stress indicators were observed in the chicken's brains. Se supplement increased the levels of GSH, mitochondrial membrane potential (MMP), and Ca 2+ -ATPase and reduced MDA activity in the detoxification groups. However, the high-dose Se supplementation groups of 2.50 and 5.00 mg/kg reduced the activities of GSH, MMP, and Ca 2+ -ATPase; increased the brain-body ratio; and increased SOD activity. In conclusion, Cr(VI) exposure caused oxidative stress. Se exerted a remission effect on toxic responses in the chicken brains. However, a high Se concentration was synergistic to the toxic effect of Cr(VI).

Association of Antioxidant Supplement Use and Dementia in the Prevention of Alzheimer's Disease by Vitamin E and Selenium Trial (PREADViSE).

PubMed

Kryscio, Richard J; Abner, Erin L; Caban-Holt, Allison; Lovell, Mark; Goodman, Phyllis; Darke, Amy K; Yee, Monica; Crowley, John; Schmitt, Frederick A

2017-05-01

Oxidative stress is an established dementia pathway, but it is unknown if the use of antioxidant supplements can prevent dementia. To determine if antioxidant supplements (vitamin E or selenium) used alone or in combination can prevent dementia in asymptomatic older men. The Prevention of Alzheimer's Disease by Vitamin E and Selenium (PREADViSE) trial began as a double-blind randomized clinical trial in May 2002, which transformed into a cohort study from September 2009 to May 2015. The PREADViSE trial was ancillary to the Selenium and Vitamin E Cancer Prevention Trial (SELECT), a randomized clinical trial of the same antioxidant supplements for preventing prostate cancer, which closed in 2009 owing to findings from a futility analysis. The PREADViSE trial recruited 7540 men, of whom 3786 continued into the cohort study. Participants were at least 60 years old at study entry and were enrolled at 130 SELECT sites, and Cox proportional hazards models were used in a modified intent-to-treat analysis to compare hazard rates among the study arms. Participants were randomized to vitamin E, selenium, vitamin E and selenium, or placebo. While taking study supplements, enrolled men visited their SELECT site and were evaluated for dementia using a 2-stage screen. During the cohort study, men were contacted by telephone and assessed using an enhanced 2-stage cognitive screen. In both phases, men were encouraged to visit their physician if the screen results indicated possible cognitive impairment. Dementia case ascertainment relied on a consensus review of the cognitive screens and medical records for men with suspected dementia who visited their physician for an evaluation or by review of all available information, including a functional assessment screen. The mean (SD) baseline age of the 7540 participants was 67.5 (5.3) years, with 3936 (52.2%) reporting a college education or better, 754 (10.0%) reporting black race, and 505 (6.7%) reporting Hispanic ethnicity. Dementia incidence (325 of 7338 men [4.4%]) was not different among the 4 study arms. A Cox model, which adjusted incidence for participant demographic information and baseline self-reported comorbidities, yielded hazard ratios of 0.88 (95% CI, 0.64-1.20) for vitamin E, 0.83 (0.60-1.13) for selenium, and 1.00 (0.75-1.35) for the combination compared with placebo. Neither supplement prevented dementia. To our knowledge, this is the first study to investigate the long-term association of antioxidant supplement use and dementia incidence among asymptomatic men.

Dietary selenium affects host selenoproteome expression by influencing the gut microbiota

PubMed Central

Kasaikina, Marina V.; Kravtsova, Marina A.; Lee, Byung Cheon; Seravalli, Javier; Peterson, Daniel A.; Walter, Jens; Legge, Ryan; Benson, Andrew K.; Hatfield, Dolph L.; Gladyshev, Vadim N.

2011-01-01

Colonization of the gastrointestinal tract and composition of the microbiota may be influenced by components of the diet, including trace elements. To understand how selenium regulates the intestinal microflora, we used high-throughput sequencing to examine the composition of gut microbiota of mice maintained on selenium-deficient, selenium-sufficient, and selenium-enriched diets. The microbiota diversity increased as a result of selenium in the diet. Specific phylotypes showed differential effects of selenium, even within a genus, implying that selenium had unique effects across microbial taxa. Conventionalized germ-free mice subjected to selenium diets gave similar results and showed an increased diversity of the bacterial population in animals fed with higher levels of selenium. Germ-free mice fed selenium diets modified their selenoproteome expression similar to control mice but showed higher levels and activity of glutathione peroxidase 1 and methionine-R-sulfoxide reductase 1 in the liver, suggesting partial sequestration of selenium by the gut microorganisms, limiting its availability for the host. These changes in the selenium status were independent of the levels of other trace elements. The data show that dietary selenium affects both composition of the intestinal microflora and colonization of the gastrointestinal tract, which, in turn, influence the host selenium status and selenoproteome expression.—Kasaikina, M. V., Kravtsova, M. A., Lee, B. C., Seravalli, J., Peterson, D. A., Walter, J., Legge, R., Benson, A. K., Hatfield, D. L., Gladyshev, V. N. Dietary selenium affects host selenoproteome expression by influencing the gut microbiota. PMID:21493887

Selenium metabolite levels in human urine after dosing selenium in different chemical forms

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hasunuma, Ryoichi; Tsuda, Morizo; Ogawa, Tadao

1993-11-01

It has been well known that selenium in marine fish such as tuna and swordfish protects the toxicity of methylmercury in vivo. The protective potency might depend on the chemical forms of selenium in the meat of marine fish sebastes and sperm whale. Little has been revealed, however, on the chemical forms of selenium in the meat of these animals or the selenium metabolites in urine, because the amount of the element is very scarce. Urine is the major excretory route for selenium. The chemical forms of urinary selenium may reflect the metabolism of the element. We have developed methodologymore » for analysis of selenium-containing components in human urine. Using this method, we have observed the time courses of excretory levels of urinary selenium components after a single dose of selenium as selenious acid, selenomethionine, trimethylselenonium ion or tuna meat. 14 refs., 6 figs., 1 tab.« less

Selenium uptake by edible oyster mushrooms (Pleurotus sp.) from selenium-hyperaccumulated wheat straw.

PubMed

Bhatia, Poonam; Prakash, Ranjana; Prakash, N Tejo

2013-01-01

In an effort to produce selenium (Se)-fortifying edible mushrooms, five species of oyster mushroom (Pleurotus sp.), were cultivated on Se-rich wheat straw collected from a seleniferous belt of Punjab, India. Total selenium was analyzed in the selenium hyperaccumulated wheat straw and the fruiting bodies. Significantly high levels (p<0.0001) of Se uptake were observed in fruiting bodies of all mushrooms grown on Se-rich wheat straw. To the best of our knowledge, accumulation and quantification of selenium in mushrooms has hitherto not been reported with substrates naturally enriched with selenium. The results demonstrate the potential of selenium-rich agricultural residues as substrates for production of Se-enriched mushrooms and the ability of different species of oyster mushrooms to absorb and fortify selenium. The study envisages potential use of selenium-rich agricultural residues towards cultivation of Se-enriched mushrooms for application in selenium supplementation or neutraceutical preparations.

Stable surface passivation process for compound semiconductors

DOEpatents

Ashby, Carol I. H.

2001-01-01

A passivation process for a previously sulfided, selenided or tellurated III-V compound semiconductor surface. The concentration of undesired mid-gap surface states on a compound semiconductor surface is reduced by the formation of a near-monolayer of metal-(sulfur and/or selenium and/or tellurium)-semiconductor that is effective for long term passivation of the underlying semiconductor surface. Starting with the III-V compound semiconductor surface, any oxidation present thereon is substantially removed and the surface is then treated with sulfur, selenium or tellurium to form a near-monolayer of chalcogen-semiconductor of the surface in an oxygen-free atmosphere. This chalcogenated surface is then contacted with a solution of a metal that will form a low solubility chalcogenide to form a near-monolayer of metal-chalcogen-semiconductor. The resulting passivating layer provides long term protection for the underlying surface at or above the level achieved by a freshly chalcogenated compound semiconductor surface in an oxygen free atmosphere.

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

PubMed

Wang, Yanbo; Yan, Xuxia; Fu, Linglin

2013-01-01

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.

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

PubMed Central

Wang, Yanbo; Yan, Xuxia; Fu, Linglin

2013-01-01

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. PMID:24204137

Evaluation of ameliorative potential of supranutritional selenium on enrofloxacin-induced testicular toxicity.

PubMed

Rungsung, Soya; Khan, Adil Mehraj; Sood, Naresh Kumar; Rampal, Satyavan; Singh Saini, Simrat Pal

2016-05-25

The study was designed to assess the ameliorative potential of selenium (Se) on enrofloxacin-induced testicular toxicity in rats. There was a significant decrease in body weight and non-significant decrease in mean testicular weight of enrofloxacin treated rats. In enrofloxacin treated rats, total sperm count and viability decreased where as sperm abnormalities increased. Testicular histopathology revealed dose dependent dysregulation of spermatogenesis and presence of necrotic debris in seminiferous tubules which was marginally improved with Se. Enrofloxacin also produced a dose dependent decrease in testosterone level. The activity of testicular antioxidant enzymes decreased where as lipid peroxidation increased in a dose-dependent manner. Se supplementation partially restored oxidative stress and sperm damage and did not affect the plasma concentrations of enrofloxacin or ciprofloxacain. The results indicate that enrofloxacin produces a dose-dependent testicular toxicity in rats that is moderately ameliorated with supranutritional Se. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Methylmercury chloride and selenomethionine interactions on health and reproduction in mallards

USGS Publications Warehouse

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

1998-01-01

Adult mallards (Anas platyrhynchos) were fed a control diet or diets containing 10 ppm mercury as methylmercury chloride, 10 ppm selenium as seleno-DL-methionine, or 10 ppm mercury plus 10 ppm selenium. One of 12 adult males fed 10 ppm mercury died and 8 others suffered from paralysis of their legs by the time the study was terminated. However, when the diet contained 10 ppm selenium in addition to the 10 ppm mercury, none of 12 males became sick. In contrast to the protective effect of selenium against mercury poisoning in males, selenium plus mercury was worse than selenium or mercury alone for some measurements of reproductive success. Both selenium and mercury lowered duckling production through reductions in hatching success and survival of ducklings, but the combination of mercury plus selenium was worse than either mercury or selenium alone. Controls produced an average of 7.6 young per female, females fed 10 ppm selenium produced an average of 2.8 young, females fed 10 ppm mercury produced 1.1 young, and females fed both mercury and selenium produced 0.2 young. Teratogenic effects also were worse for the combined mercury plus selenium treatment; deformities were recorded in 6.1% of the embryos of controls, 16.4% for methylmercury chloride, 36.2% for selenomethionine, and 73.4% for the combination of methylmercury chloride and selenomethionine. The presence of methylmercury in the diet greatly enhanced the storage of selenium in tissues. The livers of males fed 10 ppm selenium contained a mean of 9.6 ppm selenium, whereas the livers of males fed 10 ppm selenium plus 10 ppm mercury contained a mean of 114 ppm selenium. However, selenium did not enhance the storage of mercury. The results show that mercury and selenium may be antagonistic to each other for adults and synergistic to young, even within the same experiment.

[Selenium treatment in thyreopathies].

PubMed

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.

Selenium content of foods purchased or produced in Ohio.

PubMed

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.

Selenium for the Prevention of Cutaneous Melanoma

PubMed Central

Cassidy, Pamela B.; Fain, Heidi D.; Cassidy, James P.; Tran, Sally M.; Moos, Philip J.; Boucher, Kenneth M.; Gerads, Russell; Florell, Scott R.; Grossman, Douglas; Leachman, Sancy A.

2013-01-01

The role of selenium (Se) supplementation in cancer prevention is controversial; effects often depend on the nutritional status of the subject and on the chemical form in which Se is provided. We used a combination of in vitro and in vivo models to study two unique therapeutic windows for intervention in the process of cutaneous melanomagenisis, and to examine the utility of two different chemical forms of Se for prevention and treatment of melanoma. We studied the effects of Se in vitro on UV-induced oxidative stress in melanocytes, and on apoptosis and cell cycle progression in melanoma cells. In vivo, we used the HGF transgenic mouse model of UV-induced melanoma to demonstrate that topical treatment with l-selenomethionine results in a significant delay in the time required for UV-induced melanoma development, but also increases the rate of growth of those tumors once they appear. In a second mouse model, we found that oral administration of high dose methylseleninic acid significantly decreases the size of human melanoma xenografts. Our findings suggest that modestly elevation of selenium levels in the skin might risk acceleration of growth of incipient tumors. Additionally, certain Se compounds administered at very high doses could have utility for the treatment of fully-malignant tumors or prevention of recurrence. PMID:23470450

Optimization of selenizing conditions for Seleno-Lentinan and its characteristics.

PubMed

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.

Updates on clinical studies of selenium supplementation in radiotherapy

PubMed Central

2014-01-01

To establish guidelines for the selenium supplementation in radiotherapy we assessed the benefits and risks of selenium supplementation in radiotherapy. Clinical studies on the use of selenium in radiotherapy were searched in the PubMed electronic database in January 2013. Sixteen clinical studies were identified among the 167 articles selected in the initial search. Ten articles were observational studies, and the other 6 articles reported studies on the effects of selenium supplementation in patients with cancer who underwent radiotherapy. The studies were conducted worldwide including European, American and Asian countries between 1987 and 2012. Plasma, serum or whole blood selenium levels were common parameters used to assess the effects of radiotherapy and the selenium supplementation status. Selenium supplementation improved the general conditions of the patients, improved their quality of life and reduced the side effects of radiotherapy. At the dose of selenium used in these studies (200–500 μg/day), selenium supplementation did not reduce the effectiveness of radiotherapy, and no toxicities were reported. Selenium supplementation may offer specific benefits for several types of cancer patients who undergo radiotherapy. Because high-dose selenium and long-term supplementation may be unsafe due to selenium toxicity, more evidence-based information and additional research are needed to ensure the therapeutic benefits of selenium supplementation. PMID:24885670

Selenium Homeostasis and Clustering of Cardiovascular Risk Factors: A Systematic Review.

PubMed

Gharipour, Mojgan; Sadeghi, Masoumeh; Behmanesh, Mehrdad; Salehi, Mansour; Nezafati, Pouya; Gharpour, Amin

2017-10-23

  Selenium is a trace element required for a range of cellular functions. It is widely used for the biosynthesis of the unique amino acid selenocysteine [Sec], which is a structural element of selenoproteins. This systematic review focused on the possible relation between selenium and metabolic risk factors. The literature was searched via PubMed, Scopus, ISI Web of Science, and Google Scholar. Searches were not restricted by time or language. Relevant studies were selected in three phases. After an initial quality assessment, two reviewers extracted all the relevant data, whereas the third reviewer checked their extracted data. All evidence came from experimental and laboratory studies. Selenoprotein P is the best indicator for selenium nutritional levels. In addition, high levels of selenium may increase the risk of metabolic syndrome while the lack of sufficient selenium may also promote metabolic syndrome. selenium supplementation in subjects with sufficient serum selenium levels has a contrary effect on blood pressure, LDL, and total cholesterol. According to the bioavailability of different types of selenium supplementation such as selenomethionine, selenite and selenium-yeast, it seems that the best nutritional type of selenium is selenium-yeast. Regarding obtained results of longitudinal studies and randomized controlled trials, selenium supplementation should not be recommended for primary or secondary cardio-metabolic risk prevention in populations with adequate selenium status.

SOMO–HOMO Level Inversion in Biologically Important Radicals

PubMed Central

2017-01-01

Conventionally, the singly occupied molecular orbital (SOMO) of a radical species is considered to be the highest occupied molecular orbital (HOMO), but this is not the case always. In this study, we considered a number of radicals from smallest diatomic anion radicals such as superoxide anion radical to one-electron oxidized DNA related base radicals that show the SOMO is energetically lower than one or more doubly occupied molecular orbitals (MOs) (SOMO–HOMO level inversion). The electronic configurations are calculated employing the B3LYP/6-31++G** method, with the inclusion of aqueous phase via the integral equation formalism of the polarized continuum model solvation model. From the extensive study of the electronic configurations of radicals produced by one-electron oxidation or reduction of natural-DNA bases, bromine-, sulfur-, selenium-, and aza-substituted DNA bases, as well as 20 diatomic molecules, we highlight the following important findings: (i) SOMO–HOMO level inversion is a common phenomenon in radical species. (ii) The more localized spin density in σ-orbital on a single atom (carbon, nitrogen, oxygen, sulfur, or selenium), the greater the gap between HOMO and SOMO. (iii) In species with SOMO–HOMO level inversion, one-electron oxidation takes place from HOMO not from the SOMO, which produces a molecule in its triplet ground state. Oxidation of aqueous superoxide anion producing triplet molecular oxygen is one example of many. (iv) These results are for conventional radicals and in contrast with those reported for distonic radical anions in which SOMO–HOMO gaps are smaller for more localized radicals and the orbital inversions vanish in water. Our findings yield new insights into the properties of free radical systems. PMID:29240424

Nano-Se attenuates cyclophosphamide-induced pulmonary injury through modulation of oxidative stress and DNA damage in Swiss albino mice.

PubMed

Bhattacharjee, Arin; Basu, Abhishek; Biswas, Jaydip; Bhattacharya, Sudin

2015-07-01

Chemotherapy is an integral part of modern day treatment regimen but anticancer drugs fail to demarcate between cancerous and normal cells thereby causing severe form of systemic toxicity. Among which pulmonary toxicity is a dreadful complication developed in cancer patients upon cyclophosphamide (CP) therapy. Oxidative stress, fibrosis, and apoptosis are the major patho-mechanisms involved in CP-induced pulmonary toxicity. In the present study, we have synthesized Nano-Se, nanotechnology-based new form of elemental selenium which has significantly lower toxicity and acceptable bioavailability. In order to meet the need of effective drugs against CP-induced adverse effects, nano selenium (Nano-Se) was tested for its possible protective efficacy on CP-induced pulmonary toxicity and bone marrow toxicity. CP intoxication resulted in structural and functional lung impairment which was revealed by massive histopathological changes. Lung injury was associated with oxidative stress/lipid peroxidation as evident by increased in reactive oxygen species, nitric oxide level, and malondialdehyde (MDA) formation with decreased in level of antioxidants such as reduced glutathione, glutathione-S-transferase, glutathione peroxidase, superoxide dismutase, and catalase. Furthermore, CP at a dose of 25 mg/kg b.w. increased pulmonary DNA damage ('comet tail') and triggered DNA fragmentation and apoptosis in mouse bone marrow cells. On the other hand, Nano-Se at a dose of 2 mg Se/kg b.w., significantly inhibited CP-induced DNA damage in bronchoalveolar lavage cells, and decreased the apoptosis and percentage of DNA fragmentation in bone marrow cells and also antagonized the reduction of the activities of antioxidant enzymes and the increase level of MDA. Thus, our results suggest that Nano-Se in pre- and co-administration may serve as a promising preventive strategy against CP-induced pulmonary toxicity.

(p-ClPhSe)2 Reduces Hepatotoxicity Induced by Monosodium Glutamate by Improving Mitochondrial Function in Rats.

PubMed

Quines, Caroline B; Chagas, Pietro M; Hartmann, Diane; Carvalho, Nélson R; Soares, Félix A; Nogueira, Cristina W

2017-09-01

It is has been demonstrated that mitochondrial dysfunction, oxidative stress, and chronic inflammatory process are associated with progress of morbid obesity in human patients. For this reason, the searching for safe and effective antiobesity drugs has been the subject of intense research. In this context, the organic selenium compounds have attracted much attention due to their pharmacological properties, such as antihyperglycemic, antioxidant, and anti-inflammatory. The aim of this study was to evaluate the hepatoprotective action of p-chloro-diphenyl diselenide (p-ClPhSe) 2 , an organic selenium compound, in a model of obesity induced by monosodium glutamate (MSG) administration in rats. Wistar rats were treated during the first ten postnatal days with MSG (4 g/kg by subcutaneous injections) and received (p-ClPhSe) 2 (10 mg/kg, intragastrically) from 90th to 97th postnatal day. Mitochondrial function, purine content and the levels of proteins involved in apoptotic (poly [ADP-ribose] polymerase [PARP]) and inflammatory processes (inducible nitric oxide synthases [iNOS] and p38) were determined in the liver of rats. The present study, demonstrated that postnatal administration of MSG to male rats induced a mitochondrial dysfunction, accompanied by oxidative stress and an increase in the ADP levels, without altering the efficiency of phosphorylation in the liver of adult rats. Furthermore, the MSG administration also induces hepatotoxicity, through an increase in PARP, iNOS, and p38 levels. (p-ClPhSe) 2 treatment had beneficial effects against mitochondrial dysfunction, oxidative stress, and modulated protein markers of apoptosis and inflammation in the liver of MSG-treated rats. J. Cell. Biochem. 118: 2877-2886, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Preventive effects of selenium yeast, chromium picolinate, zinc sulfate and their combination on oxidative stress, inflammation, impaired angiogenesis and atherogenesis in myocardial infarction in rats.

PubMed

Al-Rasheed, Nouf M; Attia, Hala A; Mohamed, Raessa A; Al-Rasheed, Nawal M; Al-Amin, Maha A

2013-01-01

Accumulating evidences suggest a critical role of trace metal dyshemostasis in oxidative stress and cardiac dysfunction after myocardial infarction (MI). This study investigated the cardioprotective effects of selenium yeast (Se), chromium picolinate Cr(pic)3, zinc sulfate (Zn) and their combination on isoproterenol (ISO)-induced MI. Rats were divided into six groups: normal control, ISO control, Se-pretreated (0.1 mg/kg), Cr(pic)3-pretreated (400 µg/kg), Zn-pretreated (30 mg/kg) and metal combination-pretreated groups. All metals were administered for 28 days and at the 27th day, MI was induced by subcutaneous injection of ISO (85 mg/kg) once for two consecutive days. ISO control group showed hyperlipidemia, elevation of cardiac biomarkers and lipid peroxidation and increased immunostaining of p47 phox NADPH oxidase subunit in addition to decreased levels of glutathione (GSH), superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx). Cardiac levels of tumor necrosis factor-α (TNF-α) were increased, while vascular endothelial growth factor (VEGF, the major angiogenic factor) was decreased. Pretreatment with Se normalized the cardiac enzymes, lipid peroxidation, GSH, SOD, CAT, GPx, TNF-α and VEGF (P<0.001) and reduced the immunostaining of p47 phox subunit. However, Se failed to correct the dyslipidemia. Cr(pic)3 significantly improved lipid profile (P<0.001) and all other biochemical deviations except for VEGF. Zn, but to lesser extent, reduced the oxidative damage and TNF-α levels and improved both dyslipidemia and angiogenesis. Combination therapy exhibited less prominent protection compared to individual metals. Daily supplementation with trace metals is promising for improving myocardial performance via preventing oxidative damage, induction of angiogenesis, anti-inflammatory and/or anti-hyperlipidemic mechanisms.

Mobilization of selenium from the Mancos Shale and associated soils in the lower Uncompahgre River Basin, Colorado

USGS Publications Warehouse

Mast, M. Alisa; Mills, Taylor J.; Paschke, Suzanne S.; Keith, Gabrielle; Linard, Joshua I.

2014-01-01

This study investigates processes controlling mobilization of selenium in the lower part of the Uncompahgre River Basin in western Colorado. Selenium occurs naturally in the underlying Mancos Shale and is leached to groundwater and surface water by limited natural runoff, agricultural and domestic irrigation, and leakage from irrigation canals. Soil and sediment samples from the study area were tested using sequential extractions to identify the forms of selenium present in solid phases. Selenium speciation was characterized for nonirrigated and irrigated soils from an agricultural site and sediments from a wetland formed by a leaking canal. In nonirrigated areas, selenium was present in highly soluble sodium salts and gypsum. In irrigated soils, soluble forms of selenium were depleted and most selenium was associated with organic matter that was stable under near-surface weathering conditions. Laboratory leaching experiments and geochemical modeling confirm that selenium primarily is released to groundwater and surface water by dissolution of highly soluble selenium-bearing salts and gypsum present in soils and bedrock. Rates of selenium dissolution determined from column leachate experiments indicate that selenium is released most rapidly when water is applied to previously nonirrigated soils and sediment. High concentrations of extractable nitrate also were found in nonirrigated soils and bedrock that appear to be partially derived from weathered organic matter from the shale rather than from agricultural sources. Once selenium is mobilized, dissolved nitrate derived from natural sources appears to inhibit the reduction of dissolved selenium leading to elevated concentrations of selenium in groundwater. A conceptual model of selenium weathering is presented and used to explain seasonal variations in the surface-water chemistry of Loutzenhizer Arroyo, a major tributary contributor of selenium to the lower Uncompahgre River.

The Association between Selenium and Lipid Levels: a Longitudinal Study in Rural Elderly Chinese

PubMed Central

Chen, Chen; Jin, Yinlong; Unverzagt, Frederick W.; Cheng, Yibin; Hake, Ann M.; Liang, Chaoke; Ma, Feng; Su, Liqin; Liu, Jingyi; Bian, Jianchao; Li, Ping; Gao, Sujuan

2014-01-01

A protective effect of selenium on lipid levels has been reported in populations with relatively low selenium status. However, recent studies found that high selenium exposure may lead to adverse cardiometabolic effects, particularly in selenium-replete populations. We examined the associations of selenium status with changes in lipid levels in a 7-year follow up of an elderly Chinese cohort including participants from selenium-deplete areas. Study population consisted of 140 elderly Chinese aged 65 or older with nail selenium levels measured at baseline (2003-2005). Lipid concentrations were measured in fasting blood samples collected at baseline and the 7-year follow-up (2010-2012). Analysis of covariance (ANCOVA) models was used to determine the association between baseline selenium status and changes in lipid levels from baseline to follow-up adjusting for other covariates. Mean (±standard deviation) baseline selenium concentration was 0.41±0.2mg/kg. In prospective analysis, we found that individuals in the highest selenium quartile group showed 1.11 SD decrease on total-cholesterol (p<0.001), 0.41 SD increase on HDL-cholesterol (p<0.001) and 0.52 SD decrease on triglyceride after 7 years than those in the lowest selenium quartile group. The similar trends were seen with significant lipids changes in the 2th and 3th quartile groups. Selenium has modestly beneficial effects on blood lipid levels in a population with relatively low selenium status. Our result suggests adequate dietary selenium intake as a potential prevention strategy for lowering lipid levels in selenium deplete populations. PMID:25263027

Selenium in blood, semen, seminal plasma and spermatozoa of stallions and its relationship to sperm quality.

PubMed

Bertelsmann, H; Keppler, S; Höltershinken, M; Bollwein, H; Behne, D; Alber, D; Bukalis, G; Kyriakopoulos, A; Sieme, H

2010-01-01

The essential trace element selenium is indispensable for male fertility in mammals. Until now, little data existed regarding the relationship between selenium and sperm quality in the stallion. Selenium, or selenium-dependent glutathione peroxidase activity, was determined in red blood cells, semen, seminal plasma and spermatozoa, and the percentages of spermatozoa with progressive motility (PMS), intact membranes (PMI), altered (positive) acrosomal status (PAS) and detectable DNA damage, determined by the sperm chromatin structure assay, were evaluated in 41 healthy stallions (three samples each). The pregnancy rate per oestrus cycle (PRC) served as an estimation of fertility. An adverse effect on stallion fertility caused by low dietary selenium intake was excluded, as all stallions had sufficient selenium levels in their blood. Interestingly, no significant correlations (P > 0.05) between the selenium level in blood and the selenium level in seminal plasma or spermatozoa were found, suggesting that the selenium level in blood is no indicator of an adequate selenium supply for spermatogenesis. The selenium level in spermatozoa (nmol billion(-1)) was correlated with PMI, PMS and PAS (r = 0.40, r = 0.31 and r = -0.42, respectively; P

Impact of heat treatment on size, structure, and bioactivity of elemental selenium nanoparticles

PubMed Central

Zhang, Jinsong; Taylor, Ethan W; Wan, Xiaochun; Peng, Dungeng

2012-01-01

Background Elemental selenium nanoparticles have emerged as a novel selenium source with the advantage of reduced risk of selenium toxicity. The present work investigated whether heat treatment affects the size, structure, and bioactivity of selenium nanoparticles. Methods and results After a one-hour incubation of solution containing 80 nm selenium particles in a 90°C water bath, the nanoparticles aggregated into larger 110 nm particles and nanorods (290 nm × 70 nm), leading to significantly reduced bioavailability and phase II enzyme induction in selenium-deficient mice. When a solution containing 40 nm selenium nanoparticles was treated under the same conditions, the nanoparticles aggregated into larger 72 nm particles but did not transform into nanorods, demonstrating that the thermostability of selenium nanoparticles is size-dependent, smaller selenium nanoparticles being more resistant than larger selenium nanoparticles to transformation into nanorods during heat treatment. Conclusion The present results suggest that temperature and duration of the heat process, as well as the original nanoparticle size, should be carefully selected when a solution containing selenium nanoparticles is added to functional foods. PMID:22359458

Selenium: a brief review and a case report of selenium responsive cardiomyopathy

PubMed Central

2013-01-01

Background The authors review the role of selenium and highlight possible low selenium levels in soil that may result in deficient states in Saudi Arabia. Case presentation The authors report a case of selenium-responsive cardiomyopathy in a 15-month old Saudi Arabian boy. This case of selenium deficiency causing dilated cardiomyopathy is presented with failure to thrive, prolonged fever and respiratory distress. The investigations revealed selenium deficiency. Selenium supplementation along with anti-failure therapy [Furosimide, Captopril] was administered for 6 months. Following therapy the cardiac function, hair, skin and the general health of the patient improved significantly. Conclusion The patient with dilated cardiomyopathy of unknown etiology, not responding to usual medication may be deficient in selenium. Serum selenium measurements should be included in the diagnostic work-up to ensure early detection and treatment of the disease. The selenium level in the Saudi population needs be determined. Vulnerable populations have to undergo regular selenium measurements and supplementation if indicated. Dependence on processed foods suggests that the Saudi population fortify themselves with nutrient and micronutrient supplements in accordance to the RDA. PMID:23530936

Mechanism of Selenium Loss in Copper Slag

NASA Astrophysics Data System (ADS)

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

NASA Astrophysics Data System (ADS)

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.

JV Task 96 - Phase 2 - Investigating the Importance of the Mercury-Selenium Interaction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nicholas Ralston; Laura Raymond

2008-03-01

In order to improve the understanding of the mercury issue, it is vital to study mercury's effects on selenium physiology. While mercury present in the environment or food sources may pose health risks, the protective effects of selenium have not been adequately considered in establishing regulatory policy. Numerous studies report that vulnerability to mercury toxicity is inversely proportional to selenium status or level. However, selenium status has not been considered in the development of the reference dosage levels for mercury exposure. Experimental animals fed low-selenium diets are far more vulnerable to mercury toxicity than animals fed normal selenium, and animalsmore » fed selenium-rich diets are even more resistant. Selenium-dependent enzymes in brain and endocrine tissues can be impaired by excessive mercury exposure, apparently because mercury has an extremely high binding affinity for selenium. When selenium becomes bound to mercury, it is unable to participate in the metabolic cycling of selenoprotein synthesis. Because of mercury-dependent impairments of selenoprotein synthesis, various antioxidant and regulatory functions in brain biochemistry are compromised. This report details a 2-year multiclient-funded research program designed to examine the interactions between mercury and selenium in animal models. The studies explored the effects of dietary intakes of toxic amounts of methylmercury and the protective effects of the normal dietary range of selenium in counteracting mercury toxicity. This study finds that the amounts of selenium present in ocean fish are sufficient to protect against far larger quantities of methylmercury than those present in typical seafoods. Toxic effects of methylmercury exposure were not directly proportional to mercury concentrations in blood, brain, or any other tissues. Instead, mercury toxicity was proportional to molar ratios of mercury relative to selenium. In order to accurately assess risk associated with methylmercury or mercury exposures, mercury-selenium ratios appear to be far more accurate and effective in identifying risk and protecting human and environmental health. This study also finds that methylmercury toxicity can be effectively treated by dietary selenium, preventing the death and progressive disabilities that otherwise occur in methylmercury-treated subjects. Remarkably, the positive response to selenium therapy was essentially equivalent regardless of whether or not toxic amounts of methylmercury were still administered. The findings of the Physiologically Oriented Integration of Nutrients and Toxins (POINT) models of the effects of mercury and selenium developed in this project are consistent with the hypothesis that mercury toxicity arises because of mercury-dependent inhibition of selenium availability in brain and endocrine tissues. This appears to occur through synergistic effects of mercury-dependent inhibition of selenium transport to these tissues and selective sequestration of the selenium present in the tissues. Compromised transport of selenium to the brain and endocrine tissues would be particularly hazardous to the developing fetus because the rapidly growing tissues of the child have no selenium reserves. Therefore, maternal consumption of foods with high mercury-selenium ratios is hazardous. In summation, methylmercury exposure is unlikely to cause harm in populations that eat selenium-rich diets but may cause harm among populations that consume certain foods that have methylmercury present in excess of selenium.« less

Still reduced cardiovascular mortality 12 years after supplementation with selenium and coenzyme Q10 for four years: A validation of previous 10-year follow-up results of a prospective randomized double-blind placebo-controlled trial in elderly.

PubMed

Alehagen, Urban; Aaseth, Jan; Alexander, Jan; Johansson, Peter

2018-01-01

Selenium and coenzyme Q10 are both necessary for optimal cell function in the body. The intake of selenium is low in Europe, and the endogenous production of coenzyme Q10 decreases as age increases. Therefore, an intervention trial using selenium and coenzyme Q10 for four years as a dietary supplement was performed. The main publication reported reduced cardiovascular mortality as a result of the intervention. In the present sub-study the objective was to determine whether reduced cardiovascular (CV) mortality persisted after 12 years, in the supplemented population or in subgroups with diabetes, hypertension, ischemic heart disease or reduced functional capacity due to impaired cardiac function. From a rural municipality in Sweden, four hundred forty-three healthy elderly individuals were included. All cardiovascular mortality was registered, and no participant was lost to the follow-up. Based on death certificates and autopsy results, mortality was registered. After 12 years a significantly reduced CV mortality could be seen in those supplemented with selenium and coenzyme Q10, with a CV mortality of 28.1% in the active treatment group, and 38.7% in the placebo group. A multivariate Cox regression analysis demonstrated a reduced CV mortality risk in the active treatment group (HR: 0.59; 95%CI 0.42-0.81; P = 0.001). In those with ischemic heart disease, diabetes, hypertension and impaired functional capacity we demonstrated a significantly reduced CV mortality risk. This is a 12-year follow-up of a group of healthy elderly participants that were supplemented with selenium and coenzyme Q10 for four years. Even after twelve years we observed a significantly reduced risk for CV mortality in this group, as well as in subgroups of patients with diabetes, hypertension, ischemic heart disease or impaired functional capacity. The results thus validate the results obtained in the 10-year evaluation. The protective action was not confined to the intervention period, but persisted during the follow-up period. The mechanisms behind this effect remain to be fully elucidated, although various effects on cardiac function, oxidative stress, fibrosis and inflammation have previously been identified. Since this was a small study, the observations should be regarded as hypothesis-generating. Clinicaltrials.gov NCT01443780.

The antagonistic effect of selenium on cadmium-induced apoptosis via PPAR-γ/PI3K/Akt pathway in chicken pancreas.

PubMed

Jin, Xi; Jia, Tiantian; Liu, Ruohan; Xu, Shiwen

2018-06-01

The animal experiment was preformed to investigate the roles of PPAR-γ/PI3K/Akt pathway in apoptosis triggered by cadmium (Cd) and in the antagonistic effects of selenium (Se) on Cd in the pancreas of chicken. The current study showed that Cd treatment obviously increased the accumulation of Cd and directly led to lower activities of amylase, trypsin and lipase in chicken pancreas. The expression of PPAR-γ, PI3K, and Akt was declined, whereas the level of Bax, Cyt C and caspase-3 were increased in Cd group. In the result of TUNEL assay and the histological examination, typical apoptosis characteristics in the pancreas of Cd group were confirmed. Cd group also showed high levels of inducible nitric oxide synthase (iNOS) activity and nitric oxide (NO) content in pancreas. However, those Cd-induced changes were obviously alleviated in Cd + Se group. Our study revealed that Cd could impact the pancreas function and induce the activation of Bax and the overproduction of NO via PPAR-γ/PI3K/Akt pathway to promote apoptosis in chicken pancreas. However, Se could reduce Cd accumulation and antagonize Cd-triggered apoptosis in chicken pancreas. Copyright © 2018 Elsevier B.V. All rights reserved.

In vitro protection of human lymphocytes from toxic effects of chlorpyrifos by selenium-enriched medicines

PubMed Central

Navaei-Nigjeh, Mona; Asadi, Hamidreza; Baeeri, Maryam; Pedram, Sahar; Rezvanfar, Mohammad Amin; Mohammadirad, Azadeh; Abdollahi, Mohammad

2015-01-01

Objective(s): Chlorpyrifos (CP) is a broad-spectrum organophosphorus pesticide used extensively in agricultural and domestic pest control, accounting for 50% of the global insecticidal use. In the present study, protective effects of two selenium-enriched strong antioxidative medicines IMOD and Angipars were examined in human lymphocytes treated with CP in vitro. Materials and Methods: Isolated lymphocytes were exposed to 12 µg/ml CP either alone or in combination with effective doses (ED50) of IMOD (0.2 µg/ml) and Angipars (1 µg/ml). After 3 days incubation, the viability and oxidative stress markers including cellular lipid peroxidation (LPO), myeloperoxidase (MPO), total thiol molecules (TTM), and total antioxidant power (TAP) were evaluated. Also, the levels of tumor necrosis factor-α (TNF-α), as inflammatory index along with acetylcholinesterase (AChE) activity and cell apoptosis were assessed by flow cytometry. Results: Results indicated that effective doses of IMOD and Angipars reduced CP-exposed lymphocyte mortality rate along with oxidative stress. Both agents restored CP-induced elevation of TNF-α and protected the lymphocytes from CP-induced apoptosis and necrosis. Conclusion: Overall, results confirm that IMOD and Angipars reduce the toxic effects associated with CP through free radical scavenging and protection from apoptosis and necrosis. PMID:25945242

Contaminant concentrations and biomarker response in great blue heron eggs from 10 colonies on the upper Mississippi River, USA

USGS Publications Warehouse

Custer, T.W.; Hines, R.K.; Melancon, M.J.; Hoffman, D.J.; Wickliffe, J.K.; Bickham, J.W.; Martin, J.W.; Henshel, D.S.

1997-01-01

In 1993, great blue heron (Ardea herodias; GBH) eggs were collected from 10 colonies on the upper Mississippi River (UMR). They were then artificially incubated until pipping and analyzed for mercury, selenium, and organochlorines. Livers of embryos were analyzed for hepatic microsomal ethoxyresorufin-O-dealkylase (EROD) and four measures of oxidative stress. Brains were measured for asymmetry and blood was measured for the coefficient of variation of DNA (DNA VC). Organochlorine concentrations were generally low (geometric mean DDE = 1.3 ug/g wet weight; polychlorinated biphenyl [PCB] = 3.0 ug/g; 2,3,7,8-tetrachloro- -dioxin [TCDD] = 11.5 pg/g). Eggshell thickness was negatively correlated with DDE concentrations. Mercury (geometric mean = 0.8 ug/g dry weight) and selenium (3.1 ug/g dry weight) concentrations in GBH eggs were within background levels. EROD activity was not correlated with total PCBs, TCDD or toxic equivalents (TEQs) based on the relative contribution of individual PCB congeners, dibenzodioxins (PCDDs), and dibenzofurans (PCDFs) to calculated TEQs. Three of the four measures of oxidative stress were correlated with mercury concentrations. Twenty of 43 (47%) embryo brains were asymmetrical and the embryos with asymmetrical brains had higher EROD concentrations in the liver and higher DNA CV in the blood than embryos with symmetrical brains.

Extracellular micronutrient levels and pro-/antioxidant status in trauma patients with wound healing disorders: results of a cross-sectional study.

PubMed

Blass, Sandra C; Goost, Hans; Burger, Christof; Tolba, René H; Stoffel-Wagner, Birgit; Stehle, Peter; Ellinger, Sabine

2013-12-05

Disorders in wound healing (DWH) are common in trauma patients, the reasons being not completely understood. Inadequate nutritional status may favor DWH, partly by means of oxidative stress. Reliable data, however, are lacking. This study should investigate the status of extracellular micronutrients in patients with DWH within routine setting. Within a cross-sectional study, the plasma/serum status of several micronutrients (retinol, ascorbic acid, 25-hydroxycholecalciferol, α-tocopherol, β-carotene, selenium, and zinc) were determined in 44 trauma patients with DWH in addition to selected proteins (albumin, prealbumin, and C-reactive protein; CRP) and markers of pro-/antioxidant balance (antioxidant capacity, peroxides, and malondialdehyde). Values were compared to reference values to calculate the prevalence for biochemical deficiency. Correlations between CRP, albumin and prealbumin, and selected micronutrients were analyzed by Pearson's test. Statistical significance was set at P < 0.05. Mean concentrations of ascorbic acid (23.1 ± 15.9 μmol/L), 25-hydroxycholecalciferol (46.2±30.6 nmol/L), β-carotene (0.6 ± 0.4 μmol/L), selenium (0.79±0.19 μmol/L), and prealbumin (24.8 ± 8.2 mg/dL) were relatively low. Most patients showed levels of ascorbic acid (<28 μmol/L; 64%), 25-hydroxycholecalciferol (<50 μmol/L; 59%), selenium (≤ 94 μmol/L; 71%) and β-carotene (<0.9 μmol/L; 86%) below the reference range. Albumin and prealbumin were in the lower normal range and CRP was mostly above the reference range. Plasma antioxidant capacity was decreased, whereas peroxides and malondialdehyde were increased compared to normal values. Inverse correlations were found between CRP and albumin (P < 0.05) and between CRP and prealbumin (P < 0.01). Retinol (P < 0.001), ascorbic acid (P < 0.01), zinc (P < 0.001), and selenium (P < 0.001) were negatively correlated with CRP. Trauma patients with DWH frequently suffer from protein malnutrition and reduced plasma concentrations of several micronutrients probably due to inflammation, increased requirement, and oxidative burden. Thus, adequate nutritional measures are strongly recommended to trauma patients.

Reproduction in mallards fed selenium

USGS Publications Warehouse

Heinz, G.H.; Hoffman, D.J.; Krynitsky, A.J.; Weller, D.M.G.

1987-01-01

Mallards (Anas platyrhynchos) were fed diets containing 1, 5, 10, 25 or 100 ppm selenium as sodium selenite, a diet containing 10 ppm selenium as seleno-DL-methionine or a control diet. There were no effects of 1, 5 or 10 ppm selenium as sodium selenite on either weight or survival of adults or on reproductive success, and there did not appear to be a dose-response relationship at these lower levels. The 100 ppm selenium diet killed 11 of 12 adults; one adult male fed 25 ppm selenium died. Selenium at 25 and 100 ppm caused weight loss in adults. Females fed 25 ppm selenium took longer to begin laying eggs and intervals between eggs were longer than in females in other treatment groups. Hatching success appeared to be reduced in birds fed 10 ppm selenium at selenomethionine, but the reduction was not statistically significant. The survival of ducklings and the mean number of 21-d-old ducklings produced per female were reduced in the 25 ppm selenium as sodium selenite group and the 10 ppm selenium as selenomethionine group. Egg weights were not affected by any selenium treatment, but 25 ppm selenium lowered the Ratcliffe Index. Duckling weights at hatching and at 21 d of age were reduced 28 and 36%, respectively, in birds fed 25 ppm selenium, as compared with controls. Body weights measured on day 21 were lower for ducklings fed 10 ppm selenium as selenomethionine than in some other groups. Selenium in concentrations of 10 and 25 ppm as sodium selenite caused mainly embryotoxic effects, whereas 10 ppm as selenomethionine was more teratogenic, causing hydrocephaly, bill defects, eye defects (microphthalmia and anophthalmia) and foot and toe defects, including ectrodactyly. Selenomethionine was much more readily taken up by mallards and passed into their eggs than was sodium selenite, and a greater proportion of the selenium in the eggs ended up in the white when selenomethionine was fed. Adult males accumulated more selenium than did females, probably because of the females' ability to eliminate selenium in their eggs.

Toxicity of organic and inorganic selenium to mallard ducklings

USGS Publications Warehouse

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

1988-01-01

The toxicity of selenomethionine and sodium selenite to mallard ducklings (Anas platyrhynchos) was measured by feeding each form from hatching to six weeks of age at dietary concentrations of 0, 10, 20, 40, and 80 ppm selenium. At 80 ppm selenium, sodium selenite caused 97.5% mortality by six weeks and selenomethionine caused 100% mortality. At 40 ppm, these two forms of selenium caused 25 and 12.5% mortality. No mortality occurred at 10 or 20 ppm. Diets containing 20, 40, or 80 ppm selenium in both forms caused decreases in food consumption and growth. The only statistically significant effect of 10 ppm selenium was with sodium selenite, which resulted in larger livers than controls. Selenomethionine was more readily stored in the liver than sodium selenite at levels above 10 ppm selenium in the diet. Based on comparisons of residues of selenium in livers of surviving and dead ducklings, concentrations in the liver were not diagnostic of death due to selenium poisoning. Because both forms of selenium resulted in severe reductions in food consumption, selenium-induced starvation may have been related to duckling mortality. It was not clear whether either form of selenium at 10 ppm in the diet resulted in a leveling off of selenium concentrations in the liver within six weeks.

Selenium

USGS Publications Warehouse

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, waters draining from agricultural fields created wetlands with high concentrations of dissolved selenium in the water. The selenium was taken up by aquatic wildlife and caused massive numbers of embryonic deformities and deaths.Regulatory agencies have since worked to safeguard ecological and human health by creating environmental exposure guidelines based upon selenium concentrations in water and in fish tissue. Any attempt to regulate selenium concentrations requires a delicate balance because selenium occurs naturally and is also a vital nutrient for the health of wildlife, domestic stock, and humans. Selenium is commonly added as a vitamin to animal feed, and in some regions of the United States and the world, it is added as an amendment to soils for uptake by agricultural crops.The important role of selenium in economic products, energy supply, agriculture, and health will continue for well into the future. The challenge to society is to balance the benefits of selenium use with the environmental consequences of its extraction. Increased understanding of the elemental cycle of selenium in the earth may lead to new (or unconventional) sources of selenium, the discovery of new methods of extraction, and new technologies for minimizing the transfer of selenium from rock to biota, so to protect environmental and human health.

Selenium concentration and speciation in biofortified flour and bread: Retention of selenium during grain biofortification, processing and production of Se-enriched food.

PubMed

Hart, D J; Fairweather-Tait, S J; Broadley, M R; Dickinson, S J; Foot, I; Knott, P; McGrath, S P; Mowat, H; Norman, K; Scott, P R; Stroud, J L; Tucker, M; White, P J; Zhao, F J; Hurst, R

2011-06-15

The retention and speciation of selenium in flour and bread was determined following experimental applications of selenium fertilisers to a high-yielding UK wheat crop. Flour and bread were produced using standard commercial practices. Total selenium was measured using inductively coupled plasma-mass spectrometry (ICP-MS) and the profile of selenium species in the flour and bread were determined using high performance liquid chromatography (HPLC) ICP-MS. The selenium concentration of flour ranged from 30ng/g in white flour and 35ng/g in wholemeal flour from untreated plots up to >1800ng/g in white and >2200ng/g in wholemeal flour processed from grain treated with selenium (as selenate) at the highest application rate of 100g/ha. The relationship between the amount of selenium applied to the crop and the amount of selenium in flour and bread was approximately linear, indicating minimal loss of Se during grain processing and bread production. On average, application of selenium at 10g/ha increased total selenium in white and wholemeal bread by 155 and 185ng/g, respectively, equivalent to 6.4 and 7.1μg selenium per average slice of white and wholemeal bread, respectively. Selenomethionine accounted for 65-87% of total extractable selenium species in Se-enriched flour and bread; selenocysteine, Se-methylselenocysteine selenite and selenate were also detected. Controlled agronomic biofortification of wheat crops for flour and bread production could provide an appropriate strategy to increase the intake of bioavailable selenium. Copyright © 2010 Elsevier Ltd. All rights reserved.

Volatilization of selenium from astragalus plants irrigated with selenium-laden water. Open file report

DOE Office of Scientific and Technical Information (OSTI.GOV)

MacDonald, D.J.; Lujan, M.J.; Ary, T.S.

1989-01-01

Living plants of Astragalus bisulcatus and Atriplex canescens were irrigated with solutions containing selenium to investigate the plants' ability to selectively remove selenium from selenium-contaminated water. The plants were grown from seed in an indoor environment and harvested for analysis at the end of a typical 7-month growing season. Of the total selenium applied to soil in which the plants were grown, only about 1% was incorporated in plant tissues of Astragalus, but approximately 18% of applied selenium was dissipated into the air from the living plants. Atriplex plants did not absorb or dissipate detectable amounts of selenium.

Selenium and its supplementation in cardiovascular disease--what do we know?

PubMed

Benstoem, Carina; Goetzenich, Andreas; Kraemer, Sandra; Borosch, Sebastian; Manzanares, William; Hardy, Gil; Stoppe, Christian

2015-04-27

The trace element selenium is of high importance for many of the body's regulatory and metabolic functions. Balanced selenium levels are essential, whereas dysregulation can cause harm. A rapidly increasing number of studies characterizes the wide range of selenium dependent functions in the human body and elucidates the complex and multiple physiological and pathophysiological interactions of selenium and selenoproteins. For the majority of selenium dependent enzymes, several biological functions have already been identified, like regulation of the inflammatory response, antioxidant properties and the proliferation/differentiation of immune cells. Although the potential role of selenium in the development and progression of cardiovascular disease has been investigated for decades, both observational and interventional studies of selenium supplementation remain inconclusive and are considered in this review. This review covers current knowledge of the role of selenium and selenoproteins in the human body and its functional role in the cardiovascular system. The relationships between selenium intake/status and various health outcomes, in particular cardiomyopathy, myocardial ischemia/infarction and reperfusion injury are reviewed. We describe, in depth, selenium as a biomarker in coronary heart disease and highlight the significance of selenium supplementation for patients undergoing cardiac surgery.

Selenium and Its Supplementation in Cardiovascular Disease—What do We Know?

PubMed Central

Benstoem, Carina; Goetzenich, Andreas; Kraemer, Sandra; Borosch, Sebastian; Manzanares, William; Hardy, Gil; Stoppe, Christian

2015-01-01

The trace element selenium is of high importance for many of the body’s regulatory and metabolic functions. Balanced selenium levels are essential, whereas dysregulation can cause harm. A rapidly increasing number of studies characterizes the wide range of selenium dependent functions in the human body and elucidates the complex and multiple physiological and pathophysiological interactions of selenium and selenoproteins. For the majority of selenium dependent enzymes, several biological functions have already been identified, like regulation of the inflammatory response, antioxidant properties and the proliferation/differentiation of immune cells. Although the potential role of selenium in the development and progression of cardiovascular disease has been investigated for decades, both observational and interventional studies of selenium supplementation remain inconclusive and are considered in this review. This review covers current knowledge of the role of selenium and selenoproteins in the human body and its functional role in the cardiovascular system. The relationships between selenium intake/status and various health outcomes, in particular cardiomyopathy, myocardial ischemia/infarction and reperfusion injury are reviewed. We describe, in depth, selenium as a biomarker in coronary heart disease and highlight the significance of selenium supplementation for patients undergoing cardiac surgery. PMID:25923656

Effects of selenium on biological and physiological properties of the duckweed Landoltia punctata.

PubMed

Zhong, Y; Cheng, J J

2016-09-01

Duckweed can be used for bioremediation of selenium (Se) polluted water because of its capability of absorbing minerals from growing media. However, the presence of Se in the media may affect the growth of the duckweed. Landoltia punctata 7449 has been studied for its changes in chemical and biological properties with the presence of Se in the media. The duckweed was cultivated over a 12-day period at different initial concentrations of selenite (Na2 SeO3 ) from 0 to 80 μmol·l(-1) . The growth rate, the organic and total Se contents, the activity of antioxidant enzymes, the photosynthetic pigment contents, the chlorophyll a fluorescence OJIP transient, and the ultrastructure of the duckweed were monitored during the experiment. The results have shown that Se at low concentrations of ≤20 μmol·l(-1) promoted the growth of the L. punctata and inhibited lipid peroxidation. Substantial increases in duckweed growth rate and organic Se content in the duckweed were observed at low Se concentrations. The anti-oxidative effect occurred likely with the increases in guaiacol peroxidase, catalase and superoxide dismutase activities as well as the amount of photosynthetic pigments. However, negative impact to the duckweed was observed when the L. punctata was exposed to high Se concentrations (≥40 μmol·l(-1) ), in which the duckweed growth was inhibited by the selenium. The results indicate that L. punctata 7449 can be used for bioremediation of selenium (Se) polluted water when the Se concentration is ≤20 μmol·l(-1) . © 2016 German Botanical Society and The Royal Botanical Society of the Netherlands.

Determination of Glutathione, Selenium, and Malondialdehyde in Different Edible Mushroom Species.

PubMed

Dogan, Hacer; Coteli, Ebru; Karatas, Fikret

2016-12-01

In this study, the amount of reduced glutathione (GSH), oxidized glutathione (GSSG), and malondialdehyde (MDA) were determined by high performance liquid chromatography (HPLC), and selenium was determined by using the fluorescence spectrophotometer in eight different species of edible mushrooms. Brittlegill mushroom (Russula delica), meadow mushroom (Agaricus campestris), dryad's saddle mushroom (Polyporus squamosus), white button mushroom (Agaricus bisporus), Pleurotus spp., ink mushroom (Coprinus atramentarius), ebekari mushroom (slimy) (Elazığ local) and çaşır mushroom (Pleurotus eryngii) (Tunceli local) were used for analysis. The amounts of GSH, GSSG, Se, and MDA with GSH/GSSG ratio in the eight different species of edible mushrooms were observed in between 269.10 ± 16.94-1554.83 ± 58.12 μg/g; 23.55 ± 1.89-841.90 ± 20.03 μg/g; 15.06 ± 1.56-82.10 ± 3.84 μg/g; 5.46 ± 0.50-27.45 ± 2.58 μg/g wet weight and 0.32-41.35, respectively. There is a weak correlation (R 2  = 0.389) between MDA and Se, on the other hand, the correlation (R 2  = 0.831) between GSH/GSSG ratio and selenium in mushrooms are reasonable well. In a similar manner, there is a weak correlation (R 2  = 0551) between GSH/GSSG and MDA ratios in mushrooms. It was found that these edible mushroom species are good source of glutathione (GSH, GSSG), and selenium (Se) in terms of quantities obtained; therefore, it can be said that mushrooms are a rich source of antioxidants.

Mineralogical Studies Related to Endemic Diseases in Rural P. R. China

NASA Astrophysics Data System (ADS)

Belkin, H. E.; Zheng, B.; Finkelman, R. B.

2003-12-01

Domestic combustion of coal for heating and cooking is mostly confined to the world's developing countries and probably involves about 1 billion persons in China, India, Indonesia, and Africa. Various endemic diseases affecting millions of people involving arsenic, selenium, and fluorine poisoning have been associated with domestic coal combustion in rural China. We have investigated the relationship between mineralized coals (and stone coals) and disease occurrences in Guizhou and Hubei Provinces. The mineralogy of the coals has been studied by a wide variety of techniques, including optical petrography, scanning electron microscopy, electron microprobe analysis, ion probe, Synchrotron XANES-EXAFS, and Raman spectroscopy. Arsenic enrichment (up to 3 weight percent) in Upper Permian Longtan Formation coals, southwestern Guizhou Province, occurs in both 3+ and 5+ valence states. Arsenic occurs in arsenopyrite, pyrite, Al-phosphate, scorodite, Fe-oxides, and as an organically-bound species. Fluorine poisoning, much more widespread than arsenic-poisoning, is related to burning F-rich coals and F-rich clays as admixtures. Mineralogical and chemical analysis suggests that the clays contain the fluorine probably substituting for the hydroxyl group. Localized selenium poisoning in Hubei Province is related to Se-rich stone coals. The selenium occurs as a native element and in rare mandarinoite. In these three cases, knowledge of the paragenesis and mineralogy of the element enrichment in coal was vital to help understand and mitigate the endemic diseases. For the situation concerning arsenic and selenium poisoning, suspect coals have been identified and mining from these deposits has been curtailed. Fluorine has been a much more difficult problem for the local public health officials as both the coal and clay in the burning admixture can contain high fluorine. Regional geochemical and mineralogical studies will help to define coal and clay with low fluorine, suitable for domestic use.

A new tellurium-containing amphiphilic molecule induces apoptosis in HCT116 colon cancer cells.

PubMed

Du, Peng; Saidu, Nathaniel Edward Bennett; Intemann, Johanna; Jacob, Claus; Montenarh, Mathias

2014-06-01

Chalcogen-based redox modulators over the years have attracted considerable attention as anti-cancer agents. New selenium- and tellurium-containing compounds with a polar head group and aryl-groups of various lengths have recently been reported as biologically active in several organisms. In the present study, we used the most active of the tellurium compound DP41, and its selenium counterpart DP31 to investigate their effects on the human cancer cell line HCT116. Cells were treated with DP41 or DP31 and the formation of superoxide radicals was determined using dihydroethidium. Cell cycle analysis and apoptosis was determined by cytofluorimetry. Proteins involved in ER signaling and apoptosis were determined by Western blot analysis and fluorescence microscopy. With 50μM of DP41, we observed an increase in O2(-) formation. There was, however, no such increase in O2(-) after treatment with the corresponding selenium compound under the same conditions. In the case of DP41, the production of O2(-) radicals was followed by an up-regulation of Nrf2, HO-1, phospho-eIF2α and ATF4. CHOP was also induced and cells entered apoptosis. Unlike the cancer cells, normal retinal epithelial ARPE-19 cells did not produce elevated levels of O2(-) radicals nor did they induce the ER signaling pathway or apoptosis. The tellurium-containing compound DP41, in contrast to the corresponding selenium compound, induces O2(-) radical formation and oxidative and ER stress responses, including CHOP activation and finally apoptosis. These results indicate that DP41 is a redox modulating agent with promising anti-cancer potentials. Copyright © 2014 Elsevier B.V. All rights reserved.

Medical geology of endemic goiter in Kalutara, Sri Lanka; distribution and possible causes.

PubMed

Fernando, G W A R; Liyanage, P L C L; Rajapaksha, Anushka Upamali; Vithanage, Meththika

2017-12-01

This study assesses the distribution of goiter in the Kalutara District, Sri Lanka in order to find causative factors for the occurrence of goiter even after the salt iodization. A questionnaire survey was conducted at the household level and at the same time iodine and selenium levels of the water sources were analyzed. Questionnaire survey results indicated the highest numbers of goiter patients in the northern part where the lowest were found in the southern sector which may be due to the presence of acid sulfate soils. Females were more susceptible and it even showed a transmittance between generations. Average iodine concentrations in subsurface water of goiter endemic regions are 28.25 ± 15.47 μg/L whereas non-goiter regions show identical values at 24.74 ± 18.29 μg/L. Surface water exhibited relatively high values at 30.87 ± 16.13 μg/L. Endemic goiter was reported in some isolated patches where iodine and selenium concentrations low, latter was <10 μg/L. The formation of acid sulfate soils in the marshy lands in Kalutara district may lead to transformation of biological available iodine oxidation into volatile iodine by humic substances, at the same time organic matter rich peaty soil may have strong held of iodine and selenium which again induced by low pH and high temperature were suggested as the instrumental factors in the endemic goiter in Kalutara district. Hence, geochemical features such as soil pH, organic matter and thick lateritic cap in the Kalutara goiter endemic area play a role in controlling the available selenium and iodine for food chain through plant uptake and in water.

Simultaneous speciation analysis of inorganic arsenic, chromium and selenium in environmental waters by 3-(2-aminoethylamino) propyltrimethoxysilane modified multi-wall carbon nanotubes packed microcolumn solid phase extraction and ICP-MS.

PubMed

Peng, Hanyong; Zhang, Nan; He, Man; Chen, Beibei; Hu, Bin

2015-01-01

Speciation analysis of inorganic arsenic, chromium and selenium in environmental waters is of great significance for the monitoring of environmental pollution. In this work, 3-(2-aminoethylamino) propyltrimethoxysilane (AAPTS) functionalized multi-wall carbon nanotubes (MWCNTs) were synthesized and employed as the adsorbent for simultaneous speciation analysis of inorganic arsenic, chromium and selenium in environmental waters by microcolumn solid-phase extraction (SPE)-inductively coupled plasma mass spectrometry (ICP-MS). It was found that As(V), Cr(VI) and Se(VI) could be selectively adsorbed on the microcolumn packed with AAPTS-MWCNTs adsorbent at pH around 2.2, while As(III), Cr(III) and Se(IV) could not be retained at this pH and passed through the microcolumn directly. Total inorganic arsenic, chromium and selenium was determined after the oxidation of As(III), Cr(III) and Se(IV) to As(V), Cr(VI) and Se(VI) with 10.0 μmol L(-1) KMnO4. The assay of As(III), Cr(III) and Se(IV) was based on subtracting As(V), Cr(VI) and Se(VI) from the total As, Cr and Se, respectively. Under the optimized conditions, the detection limits of 15, 38 and 16 ng L(-1) with the relative standard deviations (RSDs) of 7.4, 2.4 and 6.2% (c=1 µg L(-1), n=7) were obtained for As(V), Cr(VI) and Se(VI), respectively. The developed method was validated by analyzing four Certified Reference Materials, rainwater, Yangtze River and East Lake waters. Copyright © 2014 Elsevier B.V. All rights reserved.

Effects on the accumulation of calcium, magnesium, iron, manganese, copper and zinc of adding the two inorganic forms of selenium to solution cultures of Zea mays.

PubMed

Longchamp, M; Angeli, N; Castrec-Rouelle, M

2016-01-01

The addition of selenate or selenite to common fertilizers for crop production could be an effective way of producing selenium-rich food and feed. However, this would be feasible only if the increase in plant selenium (Se) content did not negatively influence the uptake of other essential elements. We therefore need to understand the interactions between Se and other major and trace elements during uptake by the plant. This study aimed to evaluate the influence of inorganic forms of Se on the accumulation of selected macronutrients (Ca and Mg) and micronutrients (Fe, Zn, Mn and Cu). Those essential elements are involved in the oxidative balance of cells. Zea mays seedlings were grown hydroponically in growth chambers in nutrient solutions to which we added 10, 50 or 1000 μg.L(-1) of selenate and/or selenite. Cation accumulation was significantly affected by the addition of 50 μg.L(-1) or 1000 μg.L(-1) Se, but not by the presence of 10 μg.L(-1) of Se in the nutrient solution. The highest concentration (1000 μg.L(-1)) of Se in the nutrient solution affected the accumulation of essential cations in Zea mays: selenate tended to increase the accumulation of Mg, Zn and Mn, whereas a selenate/selenite mixture tended to decrease the accumulation of Ca, Mg, Zn and Mn. Only Fe accumulation was unaffected by Se whatever its form or concentration. Selenium may also affect the distribution of cations on Zea mays. For example, levels of Mg and Zn translocation to the shoots were lower in the presence of selenite. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

Selenium stable isotope ratios in California agricultural drainage water management systems

USGS Publications Warehouse

Herbel, M.J.; Johnson, T.M.; Tanji, K.K.; Gao, S.; Bullen, T.D.

2002-01-01

Selenium stable isotope ratios are known to shift in predictable ways during various microbial, chemical, and biological processes, and can be used to better understand Se cycling in contaminated environments. In this study we used Se stable isotopes to discern the mechanisms controlling the transformation of oxidized, aqueous forms of Se to reduced, insoluble forms in sediments of Se-affected environments. We measured 80Se/76Se in surface waters, shallow ground waters, evaporites, digested plants and sediments, and sequential extracts from several sites where agricultural drainage water is processed in the San Joaquin Valley of California. Selenium isotope analyses of samples obtained from the Tulare Lake Drainage District flow-through wetland reveal small isotopic contrasts (mean difference 0.7%o) between surface water and reduced Se species in the underlying sediments. Selenium in aquatic macrophytes was very similar isotopically to the NaOH and Na2SO3 sediment extracts designed to recover soluble organic Se and Se(O), respectively. For the integrated on-farm drainage management sites, evaporite salts were slightly (approximately 0.6%o) enriched in the heavier isotope relative to the inferred parent waters, whereas surface soils were slightly (approximately 1.4%o) depleted. Bacterial or chemical reduction of Se(VI) or Se(IV) may be occurring at these sites, but the small isotopic contrasts suggest that other, less isotopically fractionating mechanisms are responsible for accumulation of reduced forms in the sediments. These findings provide evidence that Se assimilation by plants and algae followed by deposition and mineralization is the dominant transformation pathway responsible for accumulation of reduced forms of Se in the wetland sediments.

Mercury and selenium levels, and selenium:mercury molar ratios of brain, muscle and other tissues in bluefish (Pomatomus saltatrix) from New Jersey, USA

PubMed Central

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

Producing selenium-enriched eggs and meat to improve the selenium status of the general population.

PubMed

Fisinin, Vladimir I; Papazyan, Tigran T; Surai, Peter F

2009-01-01

The role of selenium (Se) in human health and diseases has been discussed in detail in several recent reviews, with the main conclusion being that selenium deficiency is recognised as a global problem which urgently needs resolution. Since selenium content in plant-based food depends on its availability from soil, the level of this element in food and feeds varies among regions. In general, eggs and meat are considered to be good sources of selenium in human diet. When considering ways to improve human selenium intake, there are several potential options. These include direct supplementation, soil fertilisation and supplementation of food staples such as flour, and production of functional foods. Analysing recent publications related to functional food production, it is evident that selenium-enriched eggs can be used as an important delivery system of this trace mineral for humans. In particular, developments and commercialisation of organic forms of selenium have initiated a new era in the availability of selenium-enriched products. It has been shown that egg selenium content can easily be manipulated to give increased levels, especially when organic selenium is included in hens' diet at levels that provide 0.3-0.5 mg/kg selenium in the feed. As a result, technology for the production of eggs delivering approximately 50% (30-35 microg) of the human selenium RDA have been developed and successfully tested. Currently companies all over the world market selenium-enriched eggs including the UK, Ireland, Mexico, Columbia, Malaysia, Thailand, Australia, Turkey, Russia and the Ukraine. Prices for enriched eggs vary from country to country, typically being similar to free-range eggs. Selenium-enriched chicken, pork and beef can also be produced when using organic selenium in the diet of poultry and farm animals. The scientific, technological and other advantages and limitations of producing designer/modified eggs as functional foods are discussed in this review.

Relationship of dietary intake of fish and non-fish selenium to serum lipids in Japanese rural coastal community.

PubMed

Miyazaki, Yukiko; Koyama, Hiroshi; Nojiri, Masami; Suzuki, Shosuke

2002-01-01

Several studies have suggested that dietary selenium deficiency may be associated with an increased risk of coronary heart disease (CHD). In the present study, 55 men and 71 women were selected from participants in a health examination in a rural coastal community in Japan. The mean dietary selenium intake calculated from the simple food frequency questionnaire (SFFQ) was 127.5 micrograms/day. Fish was the major source of dietary selenium and it contributed to 68.7% of the daily total. HDL cholesterol was higher in the middle selenium intake group and in the high selenium intake group than in the low selenium intake group in all subjects and for males, and a significant difference was found between the middle selenium intake group and the low selenium intake group. The atherogenic index was significantly higher in the low selenium intake group than in the middle selenium intake group and in the high selenium intake group in males. GPx activity, total cholesterol and triacylglycerols did not show any significant differences among the three different selenium intake groups. Dietary intake of non-fish Se had a positive correlation with HDL cholesterol, and an inverse correlation with the atherogenic index in all subjects and for females. On the other hand, dietary intake of fish-Se had no relationship with any serum lipids. Non-fish Se is an important factor in selenium status for the prevention of CHD.

Selenium exposure in subjects living in areas with high selenium concentrated drinking water: results of a French integrated exposure assessment survey.

PubMed

Emmanuelle, Barron; Virginie, Migeot; Fabienne, Séby; Isabelle, Ingrand; Martine, Potin-Gautier; Bernard, Legube; Sylvie, Rabouan

2012-04-01

Selenium is an essential element which can be toxic if ingested in excessive quantities. The main human exposure is food. In addition, intake may be boosted by consumption drinking water containing unusual high selenium concentration. We measured the individual selenium level of people exposed to selenium concentration in drinking water greater than the maximum recommended limit which is 10 μg/L. We carried out a prospective cohort study on 80 adults (40 exposed subjects i.e. living in the involved area and 40 non-exposed ones i.e. living elsewhere) in western France. We used three different approaches: (1) direct measurement of ingested selenium by the duplicate portion method, (2) dietary reconstitution with a food frequency questionnaire (FFQ) and (3) evaluation of the individual selenium status by measuring the selenium content in toenail clippings. Analyses were performed by inductively coupled plasma-mass spectrometry. The association between toenail selenium concentration and area of residence was analyzed using linear regression with repeated measurements. We estimated selenium intake from FFQ at 64±14 μg/day for exposed subjects as opposed to 52±14 μg/day for the non-exposed ones. On the basis of 305 duplicate diet samples, average intake was estimated at 64±26 μg/day for exposed subjects. Area of residence (p=0.0030) and smoking (p=0.0054) were independently associated with toenail selenium concentration. Whatever method used for estimating selenium intake, the selenium level in this studied area with high selenium concentrated drinking water is much lower than in seleniferous areas. Copyright © 2011 Elsevier Ltd. All rights reserved.

Selenium requirement of shrimp Penaeus chinensis

NASA Astrophysics Data System (ADS)

Tian, Yuchuan; Liu, Fayi

1993-09-01

Penaeus chinensis were reared in fibreglass tanks for the study of their selenium requirements. The shrimp were fed semipurified diets containing graded levels of selenium, and weight gains, activities of glutatione peroxidase (GSH-Px) and selenium contents in muscle and hepatopancreas were determined. Weight gain and GSH-Px activity were the highest when the shrimp were fed diet containing 20 mg/kg selenium. Good linear correlation was found between GSH-Px activities and selenium contents in the diets, and the number of healthy shrimp. The experiment showed that 20 mg/kg selenium in the diet is optimal for the shrimp and that GSH-Px activity can be an important biochemical index of the selenium nutrition status of the animal.

Insights for Setting of Nutrient Requirements, Gleaned by Comparison of Selenium Status Biomarkers in Turkeys and Chickens versus Rats, Mice, and Lambs12

PubMed Central

Sunde, Roger A; Li, Jin-Long; Taylor, Rachel M

2016-01-01

To gain insights into nutrient biomarkers and setting of dietary nutrient requirements, selenium biomarker levels and requirements in response to multiple graded levels of dietary selenium were compared between day-old turkeys and chickens versus weanling rats and mice and 2-d-old lambs supplemented with sodium selenite. In rodents, there was no significant effect of dietary selenium on growth, indicating that the minimum selenium requirement was <0.007 μg Se/g diet. In contrast, there was a significant effect in turkeys, chicks, and lambs, which showed selenium requirements for growth of 0.05, 0.025, and 0.05 μg Se/g diet, respectively. Liver glutathione peroxidase (GPX) 1 activity fell in all species to <4% of selenium-adequate levels, plasma GPX3 activity fell to <3% in all species except for mice, and liver GPX4 activity fell to <10% in avians but only to ∼50% of selenium-adequate levels in rodents. Selenium-response curves for these biomarkers reached well-defined plateaus with increasing selenium supplementation in all species, collectively indicating minimum selenium requirements of 0.06–0.10 μg Se/g for rats, mice, and lambs but 0.10–0.13 μg Se/g for chicks and 0.23–0.33 μg Se/g for turkeys. In contrast, increasing dietary selenium did not result in well-defined plateaus for erythrocyte GPX1 activity and liver selenium in most species. Selenium-response curves for GPX1 mRNA for rodents and avians had well-defined plateaus and similar breakpoints. GPX4 mRNA was not significantly regulated by dietary selenium in rodents, but GPX4 mRNA in avians decreased in selenium deficiency to ∼35% of selenium-adequate plateau levels. Notably, no selenoprotein activities or mRNA were effective biomarkers for supernutritional selenium status. Robust biomarkers, such as liver GPX1 and plasma GPX3 activity for selenium, should be specific for the nutrient, fall dramatically in deficiency, and reach well-defined plateaus. Differences in biomarker-response curves may help researchers better understand nutrient metabolism and targeting of tissues in deficiency, thus to better characterize requirements. PMID:28140330

Insights for Setting of Nutrient Requirements, Gleaned by Comparison of Selenium Status Biomarkers in Turkeys and Chickens versus Rats, Mice, and Lambs.

PubMed

Sunde, Roger A; Li, Jin-Long; Taylor, Rachel M

2016-11-01

To gain insights into nutrient biomarkers and setting of dietary nutrient requirements, selenium biomarker levels and requirements in response to multiple graded levels of dietary selenium were compared between day-old turkeys and chickens versus weanling rats and mice and 2-d-old lambs supplemented with sodium selenite. In rodents, there was no significant effect of dietary selenium on growth, indicating that the minimum selenium requirement was <0.007 μg Se/g diet. In contrast, there was a significant effect in turkeys, chicks, and lambs, which showed selenium requirements for growth of 0.05, 0.025, and 0.05 μg Se/g diet, respectively. Liver glutathione peroxidase (GPX) 1 activity fell in all species to <4% of selenium-adequate levels, plasma GPX3 activity fell to <3% in all species except for mice, and liver GPX4 activity fell to <10% in avians but only to ∼50% of selenium-adequate levels in rodents. Selenium-response curves for these biomarkers reached well-defined plateaus with increasing selenium supplementation in all species, collectively indicating minimum selenium requirements of 0.06-0.10 μg Se/g for rats, mice, and lambs but 0.10-0.13 μg Se/g for chicks and 0.23-0.33 μg Se/g for turkeys. In contrast, increasing dietary selenium did not result in well-defined plateaus for erythrocyte GPX1 activity and liver selenium in most species. Selenium-response curves for GPX1 mRNA for rodents and avians had well-defined plateaus and similar breakpoints. GPX4 mRNA was not significantly regulated by dietary selenium in rodents, but GPX4 mRNA in avians decreased in selenium deficiency to ∼35% of selenium-adequate plateau levels. Notably, no selenoprotein activities or mRNA were effective biomarkers for supernutritional selenium status. Robust biomarkers, such as liver GPX1 and plasma GPX3 activity for selenium, should be specific for the nutrient, fall dramatically in deficiency, and reach well-defined plateaus. Differences in biomarker-response curves may help researchers better understand nutrient metabolism and targeting of tissues in deficiency, thus to better characterize requirements. © 2016 American Society for Nutrition.

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Thavarajah, D.; Vandenberg, A.; George, G.N.

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 lentilsmore » 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.« less

The APOE ε4 Allele Is Associated with Lower Selenium Levels in the Brain: Implications for Alzheimer's Disease.

PubMed

R Cardoso, Bárbara; Hare, Dominic J; Lind, Monica; McLean, Catriona A; Volitakis, Irene; Laws, Simon M; Masters, Colin L; Bush, Ashley I; Roberts, Blaine R

2017-07-19

The antioxidant activity of selenium, which is mainly conferred by its incorporation into dedicated selenoproteins, has been suggested as a possible neuroprotective approach for mitigating neuronal loss in Alzheimer's disease. However, there is inconsistent information with respect to selenium levels in the Alzheimer's disease brain. We examined the concentration and cellular compartmentalization of selenium in the temporal cortex of Alzheimer's disease and control brain tissue. We found that Alzheimer's disease was associated with decreased selenium concentration in both soluble (i.e., cytosolic) and insoluble (i.e., plaques and tangles) fractions of brain homogenates. The presence of the APOE ε4 allele correlated with lower total selenium levels in the temporal cortex and a higher concentration of soluble selenium. Additionally, we found that age significantly contributed to lower selenium concentrations in the peripheral membrane-bound and vesicular fractions. Our findings suggest a relevant interaction between APOE ε4 and selenium delivery into brain, and show changes in cellular selenium distribution in the Alzheimer's disease brain.

Toxicity of seleno-l-methionine, seleno-dl-methionine, high selenium wheat, and selenized yeast to mallard ducklings

USGS Publications Warehouse

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

1996-01-01

The toxicity of four chemical forms of selenium (seleno-L-methionine, seleno-DL-methionine, selenized yeast, and high selenium wheat) was compared in day-old mallard ducklings (Anas platyrhynchos). In the first experiment, in which the basal diet was 75% wheat, survival after 2 weeks was lower for ducklings fed 30 ?g/g selenium as seleno-L-methionine (36%) than for ducklings fed 30 ?g/g selenium as seleno-DL-methionine (100%) or 30 ?g/g selenium from high selenium yeast (88%). In a second experiment, in which the basal diet was a commercial duck feed, survival after 2 weeks was 100% in ducklings fed 30 ?g/g selenium as seleno-DL-methionine, seleno-L-methionine, or selenized yeast. The greater toxicity of the L form of selenomethionine was probably related to the palatability or nutritional nature of the wheat-based diet used in experiment 1, but the exact reason for the difference between the DL and L forms is unknown. Biologically incorporated selenium, derived from high selenium wheat was no more toxic than selenium derived from the two purified forms of selenomethionine, and the selenium in selenized yeast was not as toxic as that in the two forms of selenomethionine.

Health risk assessment of environmental selenium: Emerging evidence and challenges

PubMed Central

Vinceti, Marco; Filippini, Tommaso; Cilloni, Silvia; Bargellini, Annalisa; Vergoni, Anna Valeria; Tsatsakis, Aristides; Ferrante, Margherita

2017-01-01

New data have been accumulated in the scientific literature in recent years which allow a more adequate risk assessment of selenium with reference to human health. This new evidence comes from environmental studies, carried out in populations characterized by abnormally high or low selenium intakes, and from high-quality and large randomized controlled trials with selenium recently carried out in the US and in other countries. These trials have consistently shown no beneficial effect on cancer and cardiovascular risk, and have yielded indications of unexpected toxic effects of selenium exposure. Overall, these studies indicate that the minimal amount of environmental selenium which is source of risk to human health is much lower than anticipated on the basis of older studies, since toxic effects were shown at levels of intake as low as around 260 µg/day for organic selenium and around 16 µg/day for inorganic selenium. Conversely, populations with average selenium intake of less than 13–19 µg/day appear to be at risk of a severe cardiomyopathy, Keshan disease. Overall, there is the need to reconsider the selenium standards for dietary intake, drinking water, outdoor and indoor air levels, taking into account the recently discovered adverse health effects of low-dose selenium overexposure, and carefully assessing the significance of selenium-induced proteomic changes. PMID:28339083

Health risk assessment of environmental selenium: Emerging evidence and challenges (Review).

PubMed

Vinceti, Marco; Filippini, Tommaso; Cilloni, Silvia; Bargellini, Annalisa; Vergoni, Anna Valeria; Tsatsakis, Aristides; Ferrante, Margherita

2017-05-01

New data have been accumulated in the scientific literature in recent years which allow a more adequate risk assessment of selenium with reference to human health. This new evidence comes from environmental studies, carried out in populations characterized by abnormally high or low selenium intakes, and from high-quality and large randomized controlled trials with selenium recently carried out in the US and in other countries. These trials have consistently shown no beneficial effect on cancer and cardiovascular risk, and have yielded indications of unexpected toxic effects of selenium exposure. Overall, these studies indicate that the minimal amount of environmental selenium which is source of risk to human health is much lower than anticipated on the basis of older studies, since toxic effects were shown at levels of intake as low as around 260 µg/day for organic selenium and around 16 µg/day for inorganic selenium. Conversely, populations with average selenium intake of less than 13-19 µg/day appear to be at risk of a severe cardiomyopathy, Keshan disease. Overall, there is the need to reconsider the selenium standards for dietary intake, drinking water, outdoor and indoor air levels, taking into account the recently discovered adverse health effects of low-dose selenium overexposure, and carefully assessing the significance of selenium-induced proteomic changes.

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

PubMed

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.

[Effect of fluorine, selenium and cadmium on anti-oxidase and microelements in rat's body].

PubMed

Mou, Suhua; Qin, Si; Hu, Qituo; Duan, Xianyu

2004-03-01

To study the effect of fluorine, selenium and cadmium on lipid peroxide(LPO), the activity of glutathione peroxidase (GSH-Px) and microelements such as cadmium, selenium and zinc in rats. Measurement of the contents of LPO, GSH-Px and microelements such as cadmium, selenium and zinc in SD rats after killing that have drunk water containing fluorine, selenium and cadmium eight-week ago. The contents of GSH-Px in the serum, liver and kidney of rats that were contaminated with fluorine, selenium and cadmium respectively remarkably reduced and the content of LPO noticeably increased in comparison with those of rats without being contaminated. The contents of GSH-Px noticeably increased and LPO remarkably reduced in those contaminated with the combination of any two of the three elements when compared with those in the rats contaminated with any one element of them, while the contents of GSH-Px in those contaminated with the combination of the three elements increased even more. Excessive selenium or cadmium led to the increase of selenium content in kidney and cadmium content in liver by several times. Excessive fluorine or cadmium gave rise to the lack of selenium and zinc. Selenium brought out universal increase of zinc in liver and kidney. The combination of fluorine and selenium or the combination of cadmium and selenium or that of fluorine, selenium and cadmium produced remarkable decrease of the accumulation of selenium in kidney and cadmium in liver. They also lowed the loss of zinc caused by fluorine or cadmium. Excessive fluorine, selenium or cadmium could inhabit the activity of GSH-Px in rats, which could diminish the antioxidation ability of the body. But when two or three of the chemical elements coexisted, they reduced the inhabitation of each of them on the activity of GSH-Px and in the meantime decreased the accumulation of cadmium and selenium and diminished the loss of zinc caused by fluorine and cadmium.

An evaluation of selenium concentrations in water, sediment, invertebrates, and fish from the Republican River Basin: 1997-1999.

PubMed

May, T W; Walther, M J; Petty, J D; Fairchild, J F; Lucero, J; Delvaux, M; Manring, J; Armbruster, M; Hartman, D

2001-11-01

The Republican River Basin of Colorado, Nebraska, and Kansas lies in a valley which contains Pierre Shale as part of its geological substrata. Selenium is an indigenous constituent in the shale and is readily leached into surrounding groundwater. The Basin is heavily irrigated through the pumping of groundwater, some of which is selenium-contaminated, onto fields in agricultural production. Water, sediment, benthic invertebrates, and/or fish were collected from 46 sites in the Basin and were analyzed for selenium to determine the potential for food-chain bioaccumulation, dietary toxicity, and reproductive effects of selenium in biota. Resulting selenium concentrations were compared to published guidelines or biological effects thresholds. Water from 38% of the sites (n = 18) contained selenium concentrations exceeding 5 microg L(-1), which is reported to be a high hazard for selenium accumulation into the planktonic food chain. An additional 12 sites (26% of the sites) contained selenium in water between 3-5 microg L(-1), constituting a moderate hazard. Selenium concentrations in sediment indicated little to no hazard for selenium accumulation from sediments into the benthic food chain. Ninety-five percent of benthic invertebrates collected exhibited selenium concentrations exceeding 3 microg g(-1), a level reported as potentially lethal to fish and birds that consume them. Seventy-five percent of fish collected in 1997, 90% in 1998, and 64% in 1999 exceeded 4 microg g(-1) selenium, indicating a high potential for toxicity and reproductive effects. However, examination of weight profiles of various species of collected individual fish suggested successful recruitment in spite of selenium concentrations that exceeded published biological effects thresholds for health and reproductive success. This finding suggested that universal application of published guidelines for selenium may be inappropriate or at least may need refinement for systems similar to the Republican River Basin. Additional research is needed to determine the true impact of selenium on fish and wildlife resources in the Basin.

Selenium Polysaccharide SPMP-2a from Pleurotus geesteranus Alleviates H2O2-Induced Oxidative Damage in HaCaT Cells

PubMed Central

Zhou, Cheng; Huang, Shoucheng

2017-01-01

Selenium- (Se-) enriched polysaccharide SPMP-2a was extracted and purified from Pleurotus geesteranus. SPMP-2a is a white flocculent polysaccharide and soluble in water, with a molecular weight of 3.32 × 104 Da. Fourier transform infrared spectroscopy spectral analysis indicated that it belongs to an acid Se polysaccharide with α-D-glucopyranoside bond. The effects of Se polysaccharide SPMP-2a in P. geesteranus against hydrogen peroxide- (H2O2-) induced oxidative damage in human keratinocytes (HaCaT) cells were evaluated further. Reduced cell viability and elevated apoptotic rates in H2O2-treated HaCaT cells were proven by MTT and flow cytometry assays. Hoechst 33342 staining revealed chromatin condensations in the nuclei of HaCaT cells. However, with the addition of SPMP-2a, cell viability improved, nuclear condensation declined, and cell apoptotic rates dropped significantly. Ultrastructural observation consistently revealed that treatments with SPMP-2a reduced the number of swollen and vacuolar mitochondria in the H2O2-treated cells compared with the controls. Furthermore, SPMP-2a increased the superoxide dismutase (SOD) and catalase (CAT) activities and reduced reactive oxygen species (ROS) content. Western blot analysis showed that SPMP-2a treatment effectively increased B-cell lymphoma 2 (Bcl-2) protein expression. Therefore, SPMP-2a could improve cellular antioxidant enzyme activities, reduce ROS levels, and increase Bcl-2 protein expression levels, thereby reducing cell apoptosis and protecting HaCaT cells from H2O2-induced oxidative damage. PMID:28293636

Oral preoperative antioxidants in pancreatic surgery: a double-blind, randomized, clinical trial.

PubMed

Braga, Marco; Bissolati, Massimiliano; Rocchetti, Simona; Beneduce, Aldo; Pecorelli, Nicolò; Di Carlo, Valerio

2012-02-01

Oxidative stress due to ischemia/reperfusion injury increases systemic inflammation and impairs immune defenses. Much interest has developed for the administration of antioxidant substrates in surgical patients. The purpose of this study was to perform a pilot evaluation of the impact of a carbohydrate- containing preconditioning oral nutritional supplement (pONS) enriched with glutamine, antioxidants, and green tea extract on postoperative oxidative stress. We performed a double-blind placebo-controlled randomized clinical trial, involving 36 cancer patients undergoing pancreaticoduodenectomy. Patients were randomized to receive either pONS or placebo twice the day before surgery and once 3 hours before surgery. Total endogenous antioxidant capacity (TEAC), plasma levels of vitamin C, vitamin E, selenium, zinc, F2-isoprostanes, and C-reactive protein were measured at baseline and on postoperative day (POD) 1, 3, and 7. At surgery, the mean gastric residual volume (mL) was 54.2 in the pONS group versus 51.3 in the placebo group (P = NS). On POD 1 plasma levels of vitamin C (P = 0.001), selenium (P = 0.07), and zinc (P = 0.06) were higher in the pONS group compared to placebo. TEAC was improved on POD 1, 3, and 7 in the pONS group compared to placebo (P = 0.01). No difference was found in plasma C-reactive protein levels after surgery in both groups. Perioperative pONS administration positively affected plasma vitamin C levels and improved TEAC shortly after surgery, but did not reduce oxidative stress and systemic inflammation markers. Copyright © 2012 Elsevier Inc. All rights reserved.

The influence of nitrate on selenium in irrigated agricultural groundwater systems.

PubMed

Bailey, Ryan T; Hunter, William J; Gates, Timothy K

2012-01-01

Selenium (Se) contamination of groundwater is an environmental concern especially in areas where aquifer systems are underlain by Se-bearing geologic formations such as marine shale. This study examined the influence of nitrate (NO₃) on Se species in irrigated soil and groundwater systems and presents results from field and laboratory studies that further clarify this influence. Inhibition of selenate (SeO₄) reduction in the presence of NO₃ and the oxidation of reduced Se from shale by autotrophic denitrification were investigated. Groundwater sampling from piezometers near an alluvium-shale interface suggests that SeO₄ present in the groundwater was due in part to autotrophic denitrification. Laboratory shale oxidation batch studies indicate that autotrophic denitrification is a major driver in the release of SeO₄ and sulfate. Similar findings occurred for a shale oxidation flow-through column study, with 70 and 31% more reduced Se and S mass, respectively, removed from the shale material in the presence of NO₃ than in its absence. A final laboratory flow-through column test was performed with shallow soil samples to assess the inhibition of SeO₄ reduction in the presence of NO₃, with results suggesting that a concentration of NO₃ of approximately 5 mg L or greater will diminish the reduction of SeO₄. The inclusion of the fate and transport of NO₃ and dissolved oxygen is imperative when studying or simulating the fate and transport of Se species in soil and groundwater systems. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Selenium nanoparticles: potential in cancer gene and drug delivery.

PubMed

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.

Variations in the accumulation, localization and rate of metabolization of selenium in mature Zea mays plants supplied with selenite or selenate.

PubMed

Longchamp, Mélanie; Castrec-Rouelle, Maryse; Biron, Philippe; Bariac, Thierry

2015-09-01

Quantification of selenium bioavailability from foods is a key challenge following the discovery of the antioxidant role of this micronutrient in human health. This study presents the uptake, accumulation and rate of metabolization in mature Zea mays plants grown in hydroponic solution supplemented with selenate or selenite. Selenium content was lower in plants supplemented with selenate and accumulated mainly in the leaves compared with selenite-treated plants where the selenium was retained in the roots. Selenite-treated grains accumulated more selenium. Selenate was metabolized less than selenite in whole plants, but in grains selenium was present exclusively as organic selenium compounds. For humans, the bioavailability of organic selenium was evaluated at 90% compared with only 50% for inorganic forms. Our results show that the potential for selenium bioavailability is increased with selenite treatment. Copyright © 2015 Elsevier Ltd. All rights reserved.

The facts and controversies about selenium.

PubMed

Dodig, Slavica; Cepelak, Ivana

2004-12-01

Selenium is a trace element, essential in small amounts, but it can be toxic in larger amounts. Levels in the body are mainly dependent on the amount of selenium in the diet, which is a function of the selenium content of the soil. Humans and animals require selenium for normal functioning of more than about 30 known selenoproteins, of which approximately 15 have been purified to allow characterisation of their biological functions. Selenoproteins are comprised of four glutathione peroxidases, three iodothyronine deiodinases, three thioredoxin reductases, selenoprotein P, selenoprotein W and selenophosphate synthetase. Selenium is essential for normal functioning of the immune system and thyroid gland, making selenium an essential element for normal development, growth, metabolism, and defense of the body. Supportive function of selenium in health and disease (male infertility, viral infections, including HIV, cancer, cardiovascular and autoimmune diseases) is documented in great number of clinical examinations. A great number of studies confirm that selenium supplementation plays a preventive and therapeutical role in different diseases. Definitive evidence regarding the preventive and therapeutical role of selenium as well as the exact mechanism of its action should be investigated in further studies. Investigations in Croatia indicate a possibility of inadequate selenium status of people in the area.

High-resolution imaging of selenium in kidneys: a localized selenium pool associated with glutathione peroxidase 3

DOE Office of Scientific and Technical Information (OSTI.GOV)

Malinouski, M.; Kehr, S.; Finney, L.

2012-04-17

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. Liver showed a uniform selenium distribution that was dependent on selenocysteine tRNA{sup [Ser]Sec} and dietary selenium. In contrast, kidney selenium had both uniformly distributed and highly localized components, the latter visualized as thin circular structures surrounding proximal tubules. Other parts ofmore » the kidney, such as glomeruli and distal tubules, only manifested the uniformly distributed selenium pattern that co-localized with sulfur. We found that proximal tubule selenium localized to the basement membrane. It was preserved in Selenoprotein P knockout mice, but was completely eliminated in glutathione peroxidase 3 (GPx3) knockout mice, indicating that this selenium represented GPx3. We further imaged kidneys of another model organism, the naked mole rat, which showed a diminished uniformly distributed selenium pool, but preserved the circular proximal tubule signal. We applied XFM to image selenium in mammalian tissues and identified a highly localized pool of this trace element at the basement membrane of kidneys that was associated with GPx3. XFM allowed us to define and explain the tissue topography of selenium in mammalian kidneys at submicron resolution.« less

[Studies of bioavailability of different food sources of selenium in experiment].

PubMed

Egorova, E A; Gmoshinskiĭ, I V; Zorin, S I; Mazo, V K

2006-01-01

The selenium bioavailability in selenium enriched Spirulina (Arthrospira platensis), phycocyanin containing (Se-PC) protein isolate, separated from this micro algae and in sodium selenite was studied and compared in rats. The daily dose of selenium per one animal was 5 microgram in all experimental groups. The average selenium levels in blood serum and liver of animals that received sodium selenite during 14 days were the highest. The average selenium level in blood serum of animals fed with selenium enriched Spirulina platensis after 14 days of receiving was the same with the control group, but the average concentration of selenium in their liver was rather high and close to this parameter of sodium selenite animal group. The animals which were fed with Se-PC showed better results. Their average selenium level in blood serum was higher than in Spirulina group, but lower than in sodium selenite group. The average concentration of selenium in the liver of these animals was the same with sodium selenite animal group. As regards to animals that were fed with selenium enriched Spirulina, Se-PC and sodium selenite for 21 days, the average selenium levels ratio in their blood serum and liver was higher than in control group, but these results were not significantly different among each other. The concentrations of selenium in seminal glands in all groups of animals including control group both after 14 and 21 days feeding were close to each other.

Mercury and selenium levels, and selenium:mercury molar ratios of brain, muscle and other tissues in bluefish (Pomatomus saltatrix) from New Jersey, USA.

PubMed

Burger, Joanna; Jeitner, Christian; Donio, Mark; Pittfield, Taryn; Gochfeld, Michael

2013-01-15

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) (n=40) 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. Copyright © 2012 Elsevier B.V. All rights reserved.

Plasma and breast-milk selenium in HIV-infected Malawian mothers are positively associated with infant selenium status but are not associated with maternal supplementation: results of the Breastfeeding, Antiretrovirals, and Nutrition study.

PubMed

Flax, Valerie L; Bentley, Margaret E; Combs, Gerald F; Chasela, Charles S; Kayira, Dumbani; Tegha, Gerald; Kamwendo, Debbie; Daza, Eric J; Fokar, Ali; Kourtis, Athena P; Jamieson, Denise J; van der Horst, Charles M; Adair, Linda S

2014-04-01

Selenium is found in soils and is essential for human antioxidant defense and immune function. In Malawi, low soil selenium and dietary intakes coupled with low plasma selenium concentrations in HIV infection could have negative consequences for the health of HIV-infected mothers and their exclusively breastfed infants. We tested the effects of lipid-based nutrient supplements (LNS) that contained 1.3 times the Recommended Dietary Allowance of sodium selenite and antiretroviral drugs (ARV) on maternal plasma and breast-milk selenium concentrations. HIV-infected Malawian mothers in the Breastfeeding, Antiretrovirals, and Nutrition study were randomly assigned at delivery to receive: LNS, ARV, LNS and ARV, or a control. In a subsample of 526 mothers and their uninfected infants, we measured plasma and breast-milk selenium concentrations at 2 or 6 (depending on the availability of infant samples) and 24 wk postpartum. Overall, mean (± SD) maternal (range: 81.2 ± 20.4 to 86.2 ± 19.9 μg/L) and infant (55.6 ± 16.3 to 61.0 ± 15.4 μg/L) plasma selenium concentrations increased, whereas breast-milk selenium concentrations declined (14.3 ± 11.5 to 9.8 ± 7.3 μg/L) from 2 or 6 to 24 wk postpartum (all P < 0.001). Compared with the highest baseline selenium tertile, low and middle tertiles were positively associated with a change in maternal plasma or breast-milk selenium from 2 or 6 to 24 wk postpartum (both P < 0.001). With the use of linear regression, we showed that LNS that contained selenium and ARV were not associated with changes in maternal plasma and breast-milk selenium, but maternal selenium concentrations were positively associated with infant plasma selenium at 2 or 6 and 24 wk postpartum (P < 0.001) regardless of the study arm. Selenite supplementation of HIV-infected Malawian women was not associated with a change in their plasma or breast-milk selenium concentrations. Future research should examine effects of more readily incorporated forms of selenium (ie, selenomethionine) in HIV-infected breastfeeding women.

Controls on selenium distribution and mobilization in an irrigated shallow groundwater system underlain by Mancos Shale, Uncompahgre River Basin, Colorado, USA

USGS Publications Warehouse

Mills, Taylor J.; Mast, M. Alisa; Thomas, Judith C.; Keith, Gabrielle L.

2016-01-01

Elevated selenium (Se) concentrations in surface water and groundwater have become a concern in areas of the Western United States due to the deleterious effects of Se on aquatic ecosystems. Elevated Se concentrations are most prevalent in irrigated alluvial valleys underlain by Se-bearing marine shales where Se can be leached from geologic materials into the shallow groundwater and surface water systems. This study presents groundwater chemistry and solid-phase geochemical data from the Uncompahgre River Basin in Western Colorado, an irrigated alluvial landscape underlain by Se-rich Cretaceous marine shale. We analyzed Se species, major and trace elements, and stable nitrogen and oxygen isotopes of nitrate in groundwater and aquifer sediments to examine processes governing selenium release and transport in the shallow groundwater system. Groundwater Se concentrations ranged from below detection limit (< 0.5 μg L− 1) to 4070 μg L− 1, and primarily are controlled by high groundwater nitrate concentrations that maintain oxidizing conditions in the aquifer despite low dissolved oxygen concentrations. High nitrate concentrations in non-irrigated soils and nitrate isotopes indicate nitrate is largely derived from natural sources in the Mancos Shale and alluvial material. Thus, in contrast to areas that receive substantial NO3 inputs through inorganic fertilizer application, Se mitigation efforts that involve limiting NO3 application might have little impact on groundwater Se concentrations in the study area. Soluble salts are the primary source of Se to the groundwater system in the study area at-present, but they constitute a small percentage of the total Se content of core material. Sequential extraction results indicate insoluble Se is likely composed of reduced Se in recalcitrant organic matter or discrete selenide phases. Oxidation of reduced Se species that constitute the majority of the Se pool in the study area could be a potential source of Se in the future as soluble salts are progressively depleted.

Controls on selenium distribution and mobilization in an irrigated shallow groundwater system underlain by Mancos Shale, Uncompahgre River Basin, Colorado, USA.

PubMed

Mills, Taylor J; Mast, M Alisa; Thomas, Judith; Keith, Gabrielle

2016-10-01

Elevated selenium (Se) concentrations in surface water and groundwater have become a concern in areas of the Western United States due to the deleterious effects of Se on aquatic ecosystems. Elevated Se concentrations are most prevalent in irrigated alluvial valleys underlain by Se-bearing marine shales where Se can be leached from geologic materials into the shallow groundwater and surface water systems. This study presents groundwater chemistry and solid-phase geochemical data from the Uncompahgre River Basin in Western Colorado, an irrigated alluvial landscape underlain by Se-rich Cretaceous marine shale. We analyzed Se species, major and trace elements, and stable nitrogen and oxygen isotopes of nitrate in groundwater and aquifer sediments to examine processes governing selenium release and transport in the shallow groundwater system. Groundwater Se concentrations ranged from below detection limit (<0.5μgL(-1)) to 4070μgL(-1), and primarily are controlled by high groundwater nitrate concentrations that maintain oxidizing conditions in the aquifer despite low dissolved oxygen concentrations. High nitrate concentrations in non-irrigated soils and nitrate isotopes indicate nitrate is largely derived from natural sources in the Mancos Shale and alluvial material. Thus, in contrast to areas that receive substantial NO3 inputs through inorganic fertilizer application, Se mitigation efforts that involve limiting NO3 application might have little impact on groundwater Se concentrations in the study area. Soluble salts are the primary source of Se to the groundwater system in the study area at-present, but they constitute a small percentage of the total Se content of core material. Sequential extraction results indicate insoluble Se is likely composed of reduced Se in recalcitrant organic matter or discrete selenide phases. Oxidation of reduced Se species that constitute the majority of the Se pool in the study area could be a potential source of Se in the future as soluble salts are progressively depleted. Published by Elsevier B.V.

Electrode materials for rechargeable batteries

DOEpatents

Abouimrane, Ali; Amine, Khalil

2015-04-14

Selenium or selenium-containing compounds may be used as electroactive materials in electrodes or electrochemical devices. The selenium or selenium-containing compound is mixed with a carbon material.

Effect of forms of selenium on the accumulation of selenium, sulfur, and forms of nitrogen and phosphorus in forage cowpea (Vigna sinensis)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Singh, M.; Singh, N.

1979-05-01

The effects of forms of selenium on the accumulation of sulfur, selenium, and forms of nitrogen and phosphorus in cowpea (Vigna sinensis) were studied in pots in the greenhouse at Haryana Agricultural University, Hissar, India. The soil used was sandy, and forms of selenium added were Na/sub 2/SeO/sub 4/ 10H/sub 2/O, Na/sub 2/SeO/sub 3/ 5H/sub 2/O, H/sub 2/SeO/sub 3/, and elemental selenium at the rate of 0, 1, 2.5 and 5 ppM. Dry matter yield and sulfur content decreased with increased selenium application. This inhibition in plants, attributable to applied selenium, was in the order SeO/sub 4/ > H/sub 2/SeO/submore » 3/ > SeO/sub 3/ > elemental selenium. Plant selenium increased with increasing application of all forms of selenium. The highest plant selenium (11.58 ppM) was in the plants treated with SeO/sub 4/, followed by the plants treated with H/sub 2/SeO/sub 3/, SeO/sub 3/, and elemental selenium. The total plant phosphorus increased with increased selenium application in any form, but maximum phosphorus occurred in SeO/sub 3/-treated plants. The inorganic phosphorus increased similarly, the largest amount occurring in SeO/sub 4/-treated plants. Organic phosphorus decreased with selenium application; minimum concentration was recorded in SeO/sub 4/-treated plants. Soluble nitrogen decreased, relative to the control, with applications of 2.5 and 5 ppM selenium. This decrease was minimal for elemental selenium and maximum for SeO/sub 4/. Soluble nitrogen, in the case of SeO/sub 3/ was higher than for H/sub 2/SeO/sub 3/. Total plant nitrogen and protein also decreased. Amino N, amide N, and ammoniacal and nitrate N increased, compared to the control. The largest amount of all these forms was noted in SeO/sub 4/-treated plants. Overall, among the forms of selenium normally reported in soils, the SeO/sub 4/ form showed the highest inhibition, whereas SeO/sub 3/ showed less than both SeO/sub 4/ and H/sub 2/SeO/sub 3/.« less

Selenium extraction: development on extraction chromatographic resins compatible with Diffusive Gradient in Thin film (DGT)

NASA Astrophysics Data System (ADS)

Rad, S.; Dirks-Fandrei, C.; Happel, S. A.; Bombard, A.; Cary, L.

2016-12-01

Measurement of Selenium is of importance regarding public health as the ratio between beneficial daily intake and toxicity is rather low [1], [2]. Also from the radiological perspective, Se-79 as a long-lived fission nuclide (T1/2=2.8x105y) with high mobility in environment, is of concern regarding waste management and decommissioning [3], [4]. Due to the existence of different oxidation states Selenium has a complex speciation chemistry which makes extraction and separation schemes not straightforward. The aim of this research is to develop extraction methods for Selenium based on extraction chromatographic resins allowing for the extraction of Se(VI), as well as Se(IV), from water samples for later use on DGT (Diffusive Gradients in Thin films) devices. Extraction chromatographic resins have been tested and characterized for Se and other elements. For Se(VI) a commercially available Aliquat 336 based extraction chromatographic resin (TEVA resin[5]) was found to be most suitable, for Se(IV) a newly developed extraction chromatographic resin based on Piazselenol chemistry was found to be most effective, data on the selectivity of this resin will be presented. The extraction of Se(IV) and Se(VI) by these resins was tested on water sampled in Lille City, where a high Se spatial variability has been observed. Concentrations in groundwater can reach 30µg/L as a consequence; most Se-contaminated wells are no longer exploited by the water operators. One of the applications of this development is to be able to measure Se concentrations insitu in contaminated areas including very complex object such as hyporheic zone. [1] Cary L. et al. Applied Geochemistry 48 (2014) 70-82 [2] Chen C. et al. Biological Trace Element Research Vols. 71-72 (1999) 131-138 [3] http://www.irsn.fr/FR/Larecherche/publications-documentation/fiches-radionucleides/Documents/environnement/Selenium_Se79_v2.pdf last access 03/03/2016 [4] Uchida et al. WM2009 Conference, March 1-5, 2009, Phoenix, AZ [5] Horwitz P. et al. Analytica Chimica Acta 310 (1995) 63-78

Binding and Conversion of Selenium in Candida utilis ATCC 9950 Yeasts in Bioreactor Culture.

PubMed

Kieliszek, Marek; Błażejak, Stanisław; Kurek, Eliza

2017-02-25

Selenium is considered an essential component of all living organisms. The use of yeasts as a selenium supplement in human nutrition has gained much interest over the last decade. The accumulation and biochemical transformation of selenium in yeast cells is particularly interesting to many researchers. In this article, we present the results of the determination of selenium and selenomethionine content in the biomass of feed yeast Candida utilis ATCC 9950 obtained from the culture grown in a bioreactor. The results indicated that C. utilis cells performed the biotransformation of inorganic selenium(IV) to organic derivatives (e.g., selenomethionine). Selenium introduced (20-30 mg Se 4+ ∙L -1 ) to the experimental media in the form of sodium(IV) selenite (Na₂SeO₃) salt caused a significant increase in selenium content in the biomass of C. utilis ,irrespective of the concentration. The highest amount of selenium (1841 μg∙g d.w. -1 ) was obtained after a 48-h culture in media containing 30 mg Se 4+ ∙L -1 . The highest content of selenomethionine (238.8 μg∙g d.w. -1 ) was found after 48-h culture from the experimental medium that was supplemented with selenium at a concentration of 20 mg Se 4+ ∙L -1 . Biomass cell in the cultures supplemented with selenium ranged from 1.5 to 14.1 g∙L -1 . The results of this study indicate that yeast cell biomass of C. utilis enriched mainly with the organic forms of selenium can be a valuable source of protein. It creates the possibility of obtaining selenium biocomplexes that can be used in the production of protein-selenium dietary supplements for animals and humans.

Selenium and Selenoprotein Deficiencies Induce Widespread Pyogranuloma Formation in Mice, while High Levels of Dietary Selenium Decrease Liver Tumor Size Driven by TGFα

PubMed Central

Zhong, Nianxin; Ward, Jerrold M.; Perella, Christine M.; Hoffmann, Victoria J.; Rogers, Keith; Combs, Gerald F.; Schweizer, Ulrich; Merlino, Glenn; Gladyshev, Vadim N.; Hatfield, Dolph L.

2013-01-01

Changes in dietary selenium and selenoprotein status may influence both anti- and pro-cancer pathways, making the outcome of interventions different from one study to another. To characterize such outcomes in a defined setting, we undertook a controlled hepatocarcinogenesis study involving varying levels of dietary selenium and altered selenoprotein status using mice carrying a mutant (A37G) selenocysteine tRNA transgene (TrsptG37) and/or a cancer driver TGFα transgene. The use of TrsptG37 altered selenoprotein expression in a selenoprotein and tissue specific manner and, at sufficient dietary selenium levels, separate the effect of diet and selenoprotein status. Mice were maintained on diets deficient in selenium (0.02 ppm selenium) or supplemented with 0.1, 0.4 or 2.25 ppm selenium or 30 ppm triphenylselenonium chloride (TPSC), a non-metabolized selenium compound. TrsptG37 transgenic and TGFα/TrsptG37 bi-transgenic mice subjected to selenium-deficient or TPSC diets developed a neurological phenotype associated with early morbidity and mortality prior to hepatocarcinoma development. Pathology analyses revealed widespread disseminated pyogranulomatous inflammation. Pyogranulomas occurred in liver, lungs, heart, spleen, small and large intestine, and mesenteric lymph nodes in these transgenic and bi-transgenic mice. The incidence of liver tumors was significantly increased in mice carrying the TGFα transgene, while dietary selenium and selenoprotein status did not affect tumor number and multiplicity. However, adenoma and carcinoma size and area were smaller in TGFα transgenic mice that were fed 0.4 and 2.25 versus 0.1 ppm of selenium. Thus, selenium and selenoprotein deficiencies led to widespread pyogranuloma formation, while high selenium levels inhibited the size of TGFα–induced liver tumors. PMID:23460847

Impaired reproduction of mallards fed an organic form of selenium

USGS Publications Warehouse

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

1989-01-01

We fed mallards (Anas platyrhynchos) diets supplemented with 0-, 1-, 2-, 4-, 8-, or 16-ppm selenium in the form of selenomethionine. We fed another group of mallards a diet containing 16-ppm selenium as selenocystine. Females fed the control diet produced a mean of 8.1 ducklings that survived to 6 days of age, which was significantly greater than the 4.6 young produced by females fed 8-ppm selenium as selenomethionine and the zero surviving young of females fed 16-ppm selenium as selenomethionine. Selenocystine did not impair reproduction. Diets containing 8- and 16-ppm selenium as selenomethionine caused malformations in 6.8 and 67.9%, respectively, of unhatched eggs compared with 0.6% for controls. The most common malformations were of eyes, bill, legs, and feet. Selenium did not affect the onset or frequency of egg laying, egg size, shell thickness, fertility of eggs, or sex ratio of ducklings. Reduced survival and growth occurred in ducklings hatched from groups whose parents had received 8- or 16-ppm selenium as selenomethionine, even though all ducklings were fed a control diet. Concentrations of selenium in eggs and liver of adults could be predicted from dietary concentrations. We conclude that the dietary threshold of selenium as selenomethionine necessary to impair reproduction is between 4 and 8 ppm. It is difficult to identify 1 level of selenium in eggs that will be diagnostic of reproductive impairment in the field because different chemical forms of selenium appear to have different toxicities in eggs. However, when eggs from a wild population contain .gtoreq. 1-ppm selenium on a wet-weight basis, reproductive impairment may be possible and should be evaluated in that population. At 5-ppm selenium in eggs, reproductive impairment is much more likely to occur.

Impact of the Nationwide Intravenous Selenium Product Shortage on the Development of Selenium Deficiency in Infants Dependent on Long-Term Parenteral Nutrition.

PubMed

Chen, Connie H; Harris, Mary Beth; Partipilo, M Luisa; Welch, Kathleen B; Teitelbaum, Daniel H; Blackmer, Allison B

2016-08-01

For patients dependent on parenteral nutrition (PN), selenium must be supplemented intravenously. A nationwide intravenous selenium shortage began in April 2011. The impact of this shortage on PN-dependent infants was evaluated by examining the provision of selenium, development of biochemical deficiency, and costs associated with the shortage. This single-center, retrospective study included PN-dependent infants aged ≤1 year who weighed ≤30 kg, received PN for ≥1 month, and had ≥1 serum selenium measurement. The primary outcome was the incidence of biochemical selenium deficiency. Secondary outcomes included severity of biochemical deficiency, clinical manifestations, costs, and relationship between serum selenium levels and selenium dose. The average selenium dose decreased 2-fold during the shortage (2.1 ± 1.2 µg/kg/d; range, 0.2-4.6 µg/kg/d) versus the nonshortage period (3.8 ± 1 µg/kg/d; range, 2.4-6 µg/kg/d; P < .001). A linear relationship between serum selenium concentration and selenium dose was observed (r(2) = 0.42), with a dose of 6 µg/kg/d expected to result in normal serum levels in most cases. Similar proportions of patients developed biochemical deficiency in both groups: shortage period, 59.1%; nonshortage, 66.7%; P = .13. The severity of biochemical deficiency was similar between groups. A significant increase in incremental cost during the shortage was observed. This is the first study examining the impact of the intravenous selenium shortage on PN-dependent infants. Both groups exhibited similarly high incidences of biochemical selenium deficiency, suggesting higher empiric doses may benefit this population. However, ongoing shortages limit the ability to provide supplementation. © 2015 American Society for Parenteral and Enteral Nutrition.

Bioaccumulation and distribution of selenium in Enterococcus durans.

PubMed

Pieniz, Simone; Andreazza, Robson; Mann, Michele Bertoni; Camargo, Flávio; Brandelli, Adriano

2017-03-01

Selenium is an essential nutrient for all living organisms. Under appropriate conditions lactic acid bacteria (LAB) are capable for accumulating large amounts of trace elements, such as selenium, and incorporating them into organic compounds. In this study, the capacity of selenium bioaccumulation by Enterococcus durans LAB18s was evaluated. The distribution of organic selenium in selenium-enriched E. durans LAB18s biomass was analyzed, and the highest percentage of organic selenium was found in the fraction of total protein, followed by the fractions of polysaccharides and nucleic acids. When the protein fraction was obtained by different extractions (water, NaCl, ethanol and NaOH) it was demonstrated that alkali-soluble protein showed the higher Selenium content. Analysis of protein fractions by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) revealed that selenium was present in the proteins ranging from 23 to 100kDa. The cells were analyzed by scanning electron microscopy (SEM); scanning electron microscopy/energy dispersive spectrometry (SEM/EDS) and transmission electron microscopy (TEM). SEM, TEM and SEM/EDS showed the morphology, the selenium particles bioaccumulated into and on the cells and the amounts of selenium present into the cells, respectively. Thus, the isolate E. durans LAB18s can be a promising probiotic to be used as selenium-enriched biomass in feed trials. Copyright © 2016 Elsevier GmbH. All rights reserved.

Speciation of selenium in stream insects using X-ray absorption spectroscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ruwandi Andrahennadi; Mark Wayland; Ingrid J. Pickering

2007-11-15

Selenium contamination in the environment is a widespread problem affecting insects and other wildlife. Insects occupy a critical middle link and aid in trophic transfer of selenium in many terrestrial and freshwater food chains, but the mechanisms of selenium uptake through the food chain are poorly understood. In particular, biotransformation of selenium by insects into different chemical forms will greatly influence how toxic or benign the selenium is to that organism or to its predators. We have used X-ray absorption spectroscopy (XAS) to identify the chemical form of selenium in insects inhabiting selenium contaminated streams near Hinton, Alberta (Canada). Seleniummore » K near-edge spectra indicate a variability of selenium speciation among the insects that included mayflies (Ephemeroptera), stoneflies (Plecoptera), caddisflies (Trichoptera), and craneflies (Diptera). Higher percentages of inorganic selenium were observed in primary consumers, detritivores, and filter feeders than in predatory insects. Among the organic forms of selenium, organic selenides constituted a major fraction in most organisms. A species modeled as trimethylselenonium was observed during the pupal stage of caddisflies. These results provide insights into how the insects cope with their toxic cargo, including how the selenium is biotransformed into less toxic forms and how it can be eliminated from the insects. More broadly, this study demonstrates the strengths of XAS to probe the effects of heavy elements at trace levels in insects from the field.« less

Speciation of Selenium in Stream Insects Using X-Ray Absorption Spectroscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Andrahennadi, R.; Wayland, M.; Pickering, I.J.

2009-05-28

Selenium contamination in the environment is a widespread problem affecting insects and other wildlife. Insects occupy a critical middle link and aid in trophic transfer of selenium in many terrestrial and freshwater food chains, but the mechanisms of selenium uptake through the food chain are poorly understood. In particular, biotransformation of selenium by insects into different chemical forms will greatly influence how toxic or benign the selenium is to that organism or to its predators. We have used X-ray absorption spectroscopy (XAS) to identify the chemical form of selenium in insects inhabiting selenium contaminated streams near Hinton, Alberta (Canada). Seleniummore » K near-edge spectra indicate a variability of selenium speciation among the insects that included mayflies (Ephemeroptera), stoneflies (Plecoptera), caddisflies (Trichoptera), and craneflies (Diptera). Higher percentages of inorganic selenium were observed in primary consumers, detritivores, and filter feeders than in predatory insects. Among the organic forms of selenium, organic selenides constituted a major fraction in most organisms. A species modeled as trimethylselenonium was observed during the pupal stage of caddisflies. These results provide insights into how the insects cope with their toxic cargo, including how the selenium is biotransformed into less toxic forms and how it can be eliminated from the insects. More broadly, this study demonstrates the strengths of XAS to probe the effects of heavy elements at trace levels in insects from the field.« less

Distribution of selenium in zebrafish larvae after exposure to organic and inorganic selenium forms.

PubMed

Dolgova, N V; Hackett, M J; MacDonald, T C; Nehzati, S; James, A K; Krone, P H; George, G N; Pickering, I J

2016-03-01

Selenium is an essential micronutrient for many organisms, and in vertebrates has a variety of roles associated with protection from reactive oxygen species. Over the past two decades there have been conflicting reports upon human health benefits and detriments arising from consumption of selenium dietary supplements. Thus, early studies report a decrease in the incidence of certain types of cancer, whereas subsequent studies did not observe any anti-cancer effect, and adverse effects such as increased risks for type 2 diabetes have been reported. A possible contributing factor may be that different chemical forms of selenium were used in different studies. Using larval stage zebrafish (Danio rerio) as a model organism, we report a comparison of the toxicities and tissue selenium distributions of four different chemical forms of selenium. We find that the organic forms of selenium tested (Se-methyl-l-selenocysteine and l-selenomethionine) show considerably more toxicity than inorganic forms (selenite and selenate), and that this appears to be correlated with the level of bioaccumulation. Despite differences in concentrations, the tissue specific pattern of selenium accumulation was similar for the chemical forms tested; selenium was found to be highly concentrated in pigment (melanin) containing tissues especially for the organic selenium treatments, with lower concentrations in eye lens, yolk sac and heart. These results suggest that pigmented tissues might serve as a storage reservoir for selenium.

Selenium in diet

MedlinePlus

... Meats produced from animals that ate grains or plants found in selenium-rich soil have higher levels of selenium. Brewer's yeast, wheat germ, and enriched breads are also good sources of selenium.

Re-exposure of mallards to selenium after chronic exposure

USGS Publications Warehouse

Heinz, G.H.

1993-01-01

Adult male mallards (Anas platyrhynchos) were fed a control diet or a diet containing 15 ppm selenium as seleno-D,L-methionine for 21 weeks. After this initial exposure, the mallards were fed untreated food for 12 weeks, then were re-exposed to selenium at 100 ppm for five weeks. During re-exposure to 100 ppm selenium, the birds that had previously been exposed to 15 ppm selenium and those that had not previously been exposed did not differ in percentage of mortality (14.7 and 14.3%), weight loss in survivors (39.3 and 41.20%), selenium concentrations in the livers of survivors (35 and 53 ppm, wet weight), or selenium concentrations in the livers of birds that died (35 and 40 ppm, respectively). When the data from the birds that had previously been exposed to 15 ppm selenium were combined with the data from the birds that had not previously been exposed, selenium concentrations in the livers of birds that had died on the 100-ppm selenium treatment (38 ppm) did not differ from the concentrations in the livers of birds that had survived (43 ppm).

[The selenium haemostasis during experimental anaphylaxis reaction in rats treated with reduced glutathione and selenium enriched spirulina].

PubMed

Golubkina, N A; Mazo, V K; Gmoshinskiĭ, I V; Zorin, S N; Tambiev, A Kh; Kirikova, N N

2000-01-01

The main events caused by anaphilaxis in selenium haemostasis in rats include significant increase of selenium excretion with urine (6.36 +/- 1.18 nM Se/18 h., n = 10, compared with 1.72 +/- 0.38 nM Se/18 h., n = 10) and decrease of selenium plasma/selenium erythrocytes ratio from 0.939 to 0.791. Reduced glutathione (G-SH) administration led to 1.5-fold decrease of plasma selenium level and 1.3-fold increase of selenium concentration in intestinal walls of sensitized rats (r = -0.720, P < 0.001). Chromatographic separation of plasma proteins showed that intragastric intubation of G-SH to sensibilized rats significantly decreased the protein P content and did not influence the concentration of Se-GSHPx, thus indicating the local selenium acceptor role of G-SH. G-SH administration did not influence the intestinal permeability in sensitised rats while use of complex additive: G-SH and selenium enriched spirulina--normalized the latter parameter and the ratio of protein P/Se-GSHPx in plasma.

Randomised, double blind, placebo controlled trial of intravenous antioxidant (n‐acetylcysteine, selenium, vitamin C) therapy in severe acute pancreatitis

PubMed Central

Siriwardena, Ajith K; Mason, James M; Balachandra, Srinivasan; Bagul, Anil; Galloway, Simon; Formela, Laura; Hardman, Jonathan G; Jamdar, Saurabh

2007-01-01

Background Based on equivocal clinical data, intravenous antioxidant therapy has been used for the treatment of severe acute pancreatitis. To date there is no randomised comparison of this therapy in severe acute pancreatitis. Methods We conducted a randomised, double blind, placebo controlled trial of intravenous antioxidant (n‐acetylcysteine, selenium, vitamin C) therapy in patients with predicted severe acute pancreatitis. Forty‐three patients were enrolled from three hospitals in the Manchester (UK) area over the period June 2001 to November 2004. Randomisation stratified for APACHE‐II score and hospital site, and delivered groups that were similar at baseline. Results Relative serum levels of antioxidants rose while markers of oxidative stress fell in the active treatment group during the course of the trial. However, at 7 days, there was no statistically significant difference in the primary end point, organ dysfunction (antioxidant vs placebo: 32% vs 17%, p = 0.33) or any secondary end point of organ dysfunction or patient outcome. Conclusions This study provides no evidence to justify continued use of n‐acetylcysteine, selenium, vitamin C based antioxidant therapy in severe acute pancreatitis. In the context of any future trial design, careful consideration must be given to the risks raised by the greater trend towards adverse outcome in patients in the treatment arm of this study. PMID:17356040

Pathway of cytotoxicity induced by folic acid modified selenium nanoparticles in MCF-7 cells.

PubMed

Pi, Jiang; Jin, Hua; Liu, Ruiying; Song, Bing; Wu, Qing; Liu, Li; Jiang, Jinhuan; Yang, Fen; Cai, Huaihong; Cai, Jiye

2013-02-01

Selenium nanoparticles (Se NPs) have been recognized as promising materials for biomedical applications. To prepare Se NPs which contained cancer targeting methods and to clarify the cellular localization and cytotoxicity mechanisms of these Se NPs against cancer cells, folic acid protected/modified selenium nanoparticles (FA-Se NPs) were first prepared by a one-step method. Some morphologic and spectroscopic methods were obtained to prove the successfully formation of FA-Se NPs while free folate competitive inhibition assay, microscope, and several biological methods were used to determine the in vitro uptake, subcellular localization, and cytotoxicity mechanism of FA-Se NPs in MCF-7 cells. The results indicated that the 70-nm FA-Se NPs were internalized by MCF-7 cells through folate receptor-mediated endocytosis and targeted to mitochondria located regions through endocytic vesicles transporting. Then, the FA-Se NPs entered into mitochondria; triggered the mitochondria-dependent apoptosis of MCF-7 cells which involved oxidative stress, Ca(2)+ stress changes, and mitochondrial dysfunction; and finally caused the damage of mitochondria. FA-Se NPs released from broken mitochondria were transported into nucleus and further into nucleolus which then induced MCF-7 cell cycle arrest. In addition, FA-Se NPs could induce cytoskeleton disorganization and induce MCF-7 cell membrane morphology alterations. These results collectively suggested that FA-Se NPs could be served as potential therapeutic agents and organelle-targeted drug carriers in cancer therapy.

Reproduction of mallards following overwinter exposure to selenium

USGS Publications Warehouse

Heinz, G.H.; Fitzgerald, M.A.

1993-01-01

Forty pairs of mallards (Anas platyrhynchos) were fed 15 ppm selenium as selenomethionine for about 21 weeks during winter. Twenty pairs served as controls. At the end of 21 weeks, which coincided with the onset of the reproductive season, selenium treatment was ended. Four birds died while on selenium treatment. Treated females lost weight, and their egg-laying was delayed. Hatching success of some of the first eggs laid by selenium-treated females was lower than that of controls, and a few of these early eggs contained deformed embryos, but, after a period of about two weeks off the selenium-treated diet, reproductive success returned to a level comparable with that of controls. The return to normal reproductive success was the result of a corresponding decrease in selenium concentrations in eggs once selenium treatment ended.

An evaluation of selenium concentrations in water, sediment, invertebrates, and fish from the Republican River Basin: 1997-1999

USGS Publications Warehouse

May, T.W.; Walther, M.J.; Petty, J.D.; Fairchild, J.F.; Lucero, J.; Delvaux, M.; Manring, J.; Armbruster, M.; Hartman, D.

2001-01-01

The Republican River Basin of Colorado,Nebraska, and Kansas lies in a valley which contains PierreShale as part of its geological substrata. Selenium is anindigenous constituent in the shale and is readily leached intosurrounding groundwater. The Basin is heavily irrigated throughthe pumping of groundwater, some of which is selenium-contaminated, onto fields in agricultural production. Water,sediment, benthic invertebrates, and/or fish were collected from46 sites in the Basin and were analyzed for selenium to determinethe potential for food-chain bioaccumulation, dietary toxicity,and reproductive effects of selenium in biota. Resultingselenium concentrations were compared to published guidelines orbiological effects thresholds. Water from 38% of the sites (n = 18) contained selenium concentrations exceeding 5 μg L-1, which is reported to be a high hazard for selenium accumulation into the planktonic food chain. An additional 12 sites (26% of the sites) contained selenium in water between 3–5 μg L-1, constituting a moderate hazard. Selenium concentrations in sedimentindicated little to no hazard for selenium accumulation fromsediments into the benthic food chain. Ninety-five percent ofbenthic invertebrates collected exhibited selenium concentrationsexceeding 3 μg g-1, a level reported as potentially lethal to fish and birds that consume them. Seventy-five percent of fish collected in 1997, 90% in 1998, and 64% in 1999 exceeded 4 μg g-1selenium, indicating a high potential for toxicity andreproductive effects. However, examination of weight profilesof various species of collected individual fish suggestedsuccessful recruitment in spite of selenium concentrations thatexceeded published biological effects thresholds for health andreproductive success. This finding suggested that universalapplication of published guidelines for selenium may beinappropriate or at least may need refinement for systems similarto the Republican River Basin. Additional research is needed todetermine the true impact of selenium on fish and wildliferesources in the Basin.

Geochemistry of soils and shallow ground water, with emphasis on arsenic and selenium, in part of the Garrison Diversion Unit, North Dakota, 1985-87

USGS Publications Warehouse

Goolsby, D.A.; Severson, R.C.; Wilson, S.A.; Webber, Kurt

1989-01-01

The Garrison Diversion Unit is being constructed to transfer water from the Missouri River (Lake Sakakawea) to areas in east-central and southeastern North Dakota for expanded irrigation of agricultural lands. During initial investigations of irrigation return flows in 1969-76, the potential effects of toxic elements were considered, and the U.S. Bureau of Reclamation concluded these elements would have no adverse effects on streams receiving return flows. After the development of problems associated with selenium in irrigation return flows in the western San Joaquin Valley, Calif., in 1985, the U.S. Bureau of Reclamation initiated additional studies, including an investigation conducted in cooperation with the U.S. Geological Survey, to assist in collecting and evaluating trace-element data. Also, in 1986, with the passage of the Garrison Diversion Unit Reformulation Act, Congress mandated that soil surveys be conducted to determine if there are "*** soil characteristics which might result in toxic or hazardous irrigation return flows."In order to address this issue, an investigation was conducted during 1995-87 by the U.S. Geological Survey in cooperation with the U.S. Bureau of Reclamation to determine the occurrence and distribution of arsenic, selenium, and other trace elements in the soils of six potential irrigation areas along the Garrison Diversion Unit route and in the James River basin. A total of 165 soil samples were collected and analyzed for total concentrations of as many as 42 elements, including arsenic and selenium. In addition, 81 of the samples were analyzed for water-extractable concentrations of 14 elements, including arsenic and selenium, to aid in determining the extent to which they might be mobilized by the irrigation water. In a detailed phase of the investigation, 376 water samples were collected in one of the six potential irrigation areas, the west Oakes irrigation area. Most of these samples were analyzed for arsenic, selenium, and as many as 28 other elements.Results of the investigation indicate that soils in the potential irrigation areas contain small concentrations of arsenic, selenium, and other trace elements. The geometric mean concentrations of total arsenic and selenium were 4.15 and 0.13 milligrams per kilogram, respectively, which are considerably smaller than those measured in the western San Joaquin Valley, Calif., and soils from other areas in the western United States. Water-extractable concentrations of arsenic and selenium, determined on 1:5 soil to water extractions, generally were less than 10 percent of the total concentrations. The geometric mean water-extractable concentrations for both elements were 0.02 milligram per kilogram or less.The median and maximum concentrations of all constituents and properties indicative of irrigation drainage were tens to hundreds of times smaller in the Oakes test area drains than in western San Joaquin Valley drains. The maximum arsenic concentration in ground-water samples was 44 micrograms per liter, and the median concentration was 4 micrograms per liter. The maximum concentration in drain samples was 11 micrograms per liter, and the median concentration was 3 micrograms per liter.Only 22 percent of the water samples collected from wells in the Oakes test area contained detectable concentrations (1 microgram per liter or more) of selenium. However, selenium was detected in 63 percent of the samples collected from sites on drains. The greater incidence of detection of selenium in the drain samples is interpreted as an effect of the more oxidizing environment of the drains, which are about 8 feet below land surface near the top of the water table. The median selenium concentration in the drain samples, however, was only 1 microgram per liter, and the maximum concentration in 63 drain samples was 4 micrograms per liter. For comparison, the median selenium concentrations reported for drains in the western San Joaquin Valley, Calif., ranged from 84 to 320 micrograms per liter. Mater from two observation wells had the largest selenium concentrations (8 and 9 micrograms per liter) measured during the investigation. These were the only two samples that exceeded any of the water-quality regulations, standards, or criteria for selenium. Mercury and boron were the only other trace elements that exceeded standards and criteria. The median concentration of mercury was less than 0.1 microgram per liter, and the maximum concentration was 0.8 microgram per liter. The chronic freshwater-aquatic-life criterion for mercury (0.012 microgram per liter) is about 10 times less than the laboratory detection limit and is derived from bioconcentration factors based on methylmercury. Two boron samples exceeded the irrigation criteria of 750 micrograms per liter. Comparisons with criteria and standards indicate that the concentrations of trace elements determined in samples from wells and drains in the Oakes test area during this investigation should not adversely affect human and aquatic life or irrigated crops. The data collected indicate that the soils and ground water in the Garrison Diversion Unit contain small concentrations of trace elements, including arsenic and selenium. Based on a detailed study of soils and ground water in the west Oakes irrigation area, however, there is no evidence that expanded irrigation will mobilize these elements in concentrations large enough to adversely affect aquatic life in the James River ecosystem, based on current regulations, standards, and criteria. Data are not currently available to make definitive statements about selenium concentrations in ground water in Garrison Diversion Unit irrigation areas other than the west Oakes Irrigation area. Data available on total and water-extractable selenium concentrations in soils t however, indicate that concentrations in ground water would be similar to those determined in the west Oakes irrigation area. Plans have been developed to sample ground water in the additional areas.

Is hepatic oxidative stress a main driver of dietary selenium toxicity in white sturgeon (Acipenser transmontanus)?

PubMed

Zee, Jenna; Patterson, Sarah; Wiseman, Steve; Hecker, Markus

2016-11-01

Most species of sturgeon have experienced significant population declines and poor recruitment over the past decades, leading many, including white sturgeon (Acipenser transmontanus), to be listed as endangered. Reasons for these declines are not yet fully understood but benthic lifestyle, longevity, and delayed sexual maturation likely render sturgeon particularly susceptible to factors such as habitat alteration and contaminant exposures. One contaminant of particular concern to white sturgeon is selenium (Se), especially in its more bioavailable form selenomethionine (SeMet), as it is known to efficiently bioaccumulate in prey items of this species. Studies have shown white sturgeon to be among the most sensitive species of fish to dietary SeMet as well as other pollutants such as metals, dioxin-like chemicals and endocrine disrupters. One of the primary hypothesized mechanisms of toxicity of SeMet in fish is oxidative stress; however, little is know about the specific mode by which SeMet affects the health of white sturgeon. Therefore, the aim of this study was to characterize oxidative stress and associated antioxidant responses as a molecular event of toxicity, and to link it with the pathological effects observed previously. Specifically, three-year-old white sturgeon were exposed for 72 days via their diet to 1.4, 5.6, 22.4 or 104.4µg Se per g feed (dm). Doses were chosen to range over a necessary Se intake level, current environmentally relevant intakes and an intake representing predicted increases of Se release. Lipid hydroperoxides, which are end products of lipid oxidation, were quantified as a marker of oxidative stress. Changes in gene expression of glutathione peroxidase (GPx), superoxide dismutase, catalase, glutathione S-transferase, apoptosis inducing factor and caspase 3 were quantified as markers of the response to oxidative stress. Concentrations of lipid hydroperoxides were highly variable within dose groups and no dose response was observed. GPx expression was significantly increased in the low dose group indicating an induced antioxidant response. Expression of other genes were not significantly induced or suppressed. Overall, there was very little evidence of oxidative stress, and therefore, in contrast to previous reports on other species of teleost fishes, oxidative stress is not believed to be a main driver of toxicity in white sturgeon exposed to SeMet. Copyright © 2016 Elsevier Inc. All rights reserved.

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

PubMed Central

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.

2012-01-01

Abstract 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 distribution that was dependent on selenocysteine tRNA[Ser]Sec and dietary selenium. In contrast, kidney selenium had both uniformly distributed and highly localized components, the latter visualized as thin circular structures surrounding proximal tubules. Other parts of the kidney, such as glomeruli and distal tubules, only manifested the uniformly distributed selenium pattern that co-localized with sulfur. We found that proximal tubule selenium localized to the basement membrane. It was preserved in Selenoprotein P knockout mice, but was completely eliminated in glutathione peroxidase 3 (GPx3) knockout mice, indicating that this selenium represented GPx3. We further imaged kidneys of another model organism, the naked mole rat, which showed a diminished uniformly distributed selenium pool, but preserved the circular proximal tubule signal. Innovation: We applied XFM to image selenium in mammalian tissues and identified a highly localized pool of this trace element at the basement membrane of kidneys that was associated with GPx3. Conclusion: XFM allowed us to define and explain the tissue topography of selenium in mammalian kidneys at submicron resolution. Antioxid. Redox Signal. 16, 185–192. PMID:21854231

Red selenium nanoparticles and gray selenium nanorods as antibacterial coatings for PEEK medical devices.

PubMed

Wang, Qi; Mejía Jaramillo, Alejandra; Pavon, Juan J; Webster, Thomas J

2016-10-01

Bacterial infections are commonly found on various poly(ether ether ketone) (PEEK) medical devices (such as orthopedic instruments, spinal fusion devices, and segments in dialysis equipment), and thus, there is a significant need for introducing antibacterial properties to such materials. The objective of this in vitro study was to introduce antibacterial properties to PEEK medical devices by coating them with nanosized selenium. In this study, red selenium (an elemental form of selenium) nanoparticles were coated on PEEK medical devices through a quick precipitation method. Furthermore, with heat treatment at 100°C for 6 days, red selenium nanoparticles were transferred into gray selenium nanorods on the PEEK surfaces. Bacteria test results showed that both red and gray selenium-coated PEEK medical devices significantly inhibited the growth of Pseudomonas aeruginosa compared with uncoated PEEK after either 1, 2, or 3 days. Red selenium nanoparticle-coated PEEK showed less bacteria growth on its surface than gray selenium nanorod-coated PEEK after 3 days. This study demonstrated that red, and to a lesser extent gray, nanosized selenium could be used as potential antibacterial coatings to prevent bacteria function on PEEK medical devices. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 104B: 1352-1358, 2016. © 2015 Wiley Periodicals, Inc.

Loss of selenium-binding protein 1 decreases sensitivity to clastogens and intracellular selenium content in HeLa cells

USDA-ARS?s Scientific Manuscript database

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 ...

In vivo synthesis of nano-selenium by Tetrahymena thermophila SB210.

PubMed

Cui, Yin-Hua; Li, Ling-Li; Zhou, Nan-Qing; Liu, Jing-Hua; Huang, Qing; Wang, Hui-Juan; Tian, Jie; Yu, Han-Qing

2016-12-01

Nano-selenium has a great potential to be used in chemical, biological, medical and environmental fields. Biological methods for nano-selenium synthesis have attracted wide interests, because they can be operated at ambient temperature and pressure without complicated equipments. In this work, a protozoa, Tetrahymena thermophila (T. thermophila) SB210, was used to in vivo synthesize nano-selenium. The biosynthesized nano-selenium was characterized using transmission electron microscopy, energy dispersive X-ray spectroscopy and Raman spectroscopy. The synthesized amorphous spherical selenium nanoparticles had diameters of 50-500nm with the coexistence of irregular nano-selenium. The expressions of glutathione (GSH) synthesis related gene glutathione synthase, cysteine-rich protein metallothionein related gene metallothionein-1 and [2Fe-2S] cluster-binding protein related gene were up-regulated in the nano-selenium producing group. Also, the subsequent GSH detection and in vitro synthesis experimental results suggest the three proteins were likely to be involved in the nano-selenium synthesis process. Copyright © 2016 Elsevier Inc. All rights reserved.

Selenium in fly ash

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gutenmann, W.H.; Bache, C.A.; Youngs, W.D.

1976-03-05

Selenium, at concentrations exceeding 200 parts per million (ppM) (dry weight), has been found in white sweet clover voluntarily growing on beds of fly ash in central New York State. Guinea pigs fed such clover concentrated selenium in their tissues. The contents of the honey stomachs of bees foraging on this seleniferous clover contained negligible selenium. Mature vegetables cultured on 10 percent (by weight) fly ash-amended soil absorbed up to 1 ppM of selenium. Fly ashes from 21 states contained total selenium contents ranging from 1.2 to 16.5 ppM. Cabbage grown on soil containing 10 percent (by weight) of thesemore » fly ashes absorbed selenium (up to 3.7 ppM) in direct proportion (correlation coefficient r = .89) to the selenium concentration in the respective fly ash. Water, aquatic weeds, algae, dragonfly nymphs, polliwogs, and tissues of bullheads and muskrats from a fly ash-contaminated pond contained concentrations of selenium markedly elevated over those of controls.« less

Tissue distribution of selenium and effect of season and age on selenium content in roe deer from northwestern Poland.

PubMed

Pilarczyk, Bogumiła; Tomza-Marciniak, Agnieszka; Pilarczyk, Renata; Hendzel, Diana; Błaszczyk, Barbara; Bąkowska, Małgorzata

2011-06-01

The aim of the study was to compare selenium concentrations in different organs of roe deer from northwestern Poland. Samples of liver, kidneys, heart and lungs, collected from 74 roe deer shot during the hunting seasons of 2008-2009 in northwestern Poland, were studied. Selenium concentration in the organs was determined spectrofluorimetrically. Mean selenium concentration was 0.06 µg/g w.w. in the liver, 0.41 µg/g w.w. in the kidneys and 0.05 µg/g w.w. in the heart and lungs. Season had a significant effect on selenium concentration in the liver, kidneys, lungs and heart. In all the organs, the highest selenium concentration was found in spring and the lowest in autumn and winter. All animals studied were deficient in selenium. The low selenium concentration in the liver or heart can disturb their function, and in the future, it may be a factor contributing to the population decline of roe deer in the northwestern part of Poland.

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

PubMed Central

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

Plasma and breast-milk selenium in HIV-infected Malawian mothers are positively associated with infant selenium status but are not associated with maternal supplementation: results of the Breastfeeding, Antiretrovirals, and Nutrition study123

PubMed Central

Flax, Valerie L; Bentley, Margaret E; Combs, Gerald F; Chasela, Charles S; Kayira, Dumbani; Tegha, Gerald; Kamwendo, Debbie; Daza, Eric J; Fokar, Ali; Kourtis, Athena P; Jamieson, Denise J; van der Horst, Charles M; Adair, Linda S

2014-01-01

Background: Selenium is found in soils and is essential for human antioxidant defense and immune function. In Malawi, low soil selenium and dietary intakes coupled with low plasma selenium concentrations in HIV infection could have negative consequences for the health of HIV-infected mothers and their exclusively breastfed infants. Objective: We tested the effects of lipid-based nutrient supplements (LNS) that contained 1.3 times the Recommended Dietary Allowance of sodium selenite and antiretroviral drugs (ARV) on maternal plasma and breast-milk selenium concentrations. Design: HIV-infected Malawian mothers in the Breastfeeding, Antiretrovirals, and Nutrition study were randomly assigned at delivery to receive: LNS, ARV, LNS and ARV, or a control. In a subsample of 526 mothers and their uninfected infants, we measured plasma and breast-milk selenium concentrations at 2 or 6 (depending on the availability of infant samples) and 24 wk postpartum. Results: Overall, mean (±SD) maternal (range: 81.2 ± 20.4 to 86.2 ± 19.9 μg/L) and infant (55.6 ± 16.3 to 61.0 ± 15.4 μg/L) plasma selenium concentrations increased, whereas breast-milk selenium concentrations declined (14.3 ± 11.5 to 9.8 ± 7.3 μg/L) from 2 or 6 to 24 wk postpartum (all P < 0.001). Compared with the highest baseline selenium tertile, low and middle tertiles were positively associated with a change in maternal plasma or breast-milk selenium from 2 or 6 to 24 wk postpartum (both P < 0.001). With the use of linear regression, we showed that LNS that contained selenium and ARV were not associated with changes in maternal plasma and breast-milk selenium, but maternal selenium concentrations were positively associated with infant plasma selenium at 2 or 6 and 24 wk postpartum (P < 0.001) regardless of the study arm. Conclusions: Selenite supplementation of HIV-infected Malawian women was not associated with a change in their plasma or breast-milk selenium concentrations. Future research should examine effects of more readily incorporated forms of selenium (ie, selenomethionine) in HIV-infected breastfeeding women. This trial was registered at clinicaltrials.gov as NCT00164736. PMID:24500152

Selenium Supranutrition: Are the Potential Benefits of Chemoprevention Outweighed by the Promotion of Diabetes and Insulin Resistance?

PubMed Central

Rocourt, Caroline R. B.; Cheng, Wen-Hsing

2013-01-01

Selenium was considered a toxin until 1957, when this mineral was shown to be essential in the prevention of necrotic liver damage in rats. The hypothesis of selenium chemoprevention is principally formulated by the observations that cancer incidence is inversely associated with selenium status. However, recent clinical and epidemiological studies demonstrate a role for some selenoproteins in exacerbating or promoting other disease states, specifically type 2 diabetes, although other data support a role of selenium in stimulating insulin sensitivity. Therefore, it is clear that our understanding in the role of selenium in glucose metabolism and chemoprevention is inadequate and incomplete. Research exploring the role of selenium in individual healthcare is of upmost importance and possibly will help explain how selenium is a double-edged sword in the pathologies of chronic diseases. PMID:23603996

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

PubMed

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.

Genetic polymorphisms that affect selenium status and response to selenium supplementation in United Kingdom pregnant women1

PubMed Central

Mao, Jinyuan; Vanderlelie, Jessica J; Perkins, Anthony V; Redman, Christopher WG; Ahmadi, Kourosh R; Rayman, Margaret P

2016-01-01

Background: Low selenium status in pregnancy has been associated with a number of adverse conditions. In nonpregnant populations, the selenium status or response to supplementation has been associated with polymorphisms in dimethylglycine dehydrogenase (DMGDH), selenoprotein P (SEPP1) and the glutathione peroxidases [cytosolic glutathione peroxidase (GPx1) and phospholipid glutathione peroxidase (GPx4)]. Objective: We hypothesized that, in pregnant women, these candidate polymorphisms would be associated with selenium status in early pregnancy, its longitudinal change, and the interindividual response to selenium supplementation at 60 μg/d. Design: With the use of stored samples and data from the United Kingdom Selenium in Pregnancy Intervention (SPRINT) study in 227 pregnant women, we carried out genetic-association studies, testing for associations between selenium status, its longitudinal change, and response to supplementation and common genetic variation in DMGDH (rs921943), SEPP1 (rs3877899 and rs7579), GPx1 (rs1050450) and GPx4 (rs713041). Selenium status was represented by the concentration of whole-blood selenium at 12 and 35 wk of gestation, the concentration of toenail selenium at 16 wk of gestation, and plasma glutathione peroxidase (GPx3) activity at 12 and 35 wk of gestation. Results: Our results showed that DMGDH rs921943 was significantly associated with the whole-blood selenium concentration at 12 wk of gestation (P = 0.032), which explained ≤2.0% of the variance. This association was replicated with the use of toenail selenium (P = 0.043). In unsupplemented women, SEPP1 rs3877899 was significantly associated with the percentage change in whole-blood selenium from 12 to 35 wk of gestation (P = 0.005), which explained 8% of the variance. In supplemented women, SEPP1 rs3877899 was significantly associated with the percentage change in GPx3 activity from 12 to 35 wk of gestation (P = 0.01), which explained 5.3% of the variance. Selenium status was not associated with GPx1, GPx4, or SEPP1 rs7579. Conclusions: In agreement with previous studies, we show that the genetic variant rs921943 in DMGDH is significantly associated with selenium status in United Kingdom pregnant women. Notably, our study shows that women who carry the SEPP1 rs3877899 A allele are better able to maintain selenium status during pregnancy, and their GPx3 activity increases more with supplementation, which suggests better protection from low selenium status. The SPRINT study was registered at www.isrctn.com as ISRCTN37927591. PMID:26675765

Chemistry of Renieramycins. Part 14: Total Synthesis of Renieramycin I and Practical Synthesis of Cribrostatin 4 (Renieramycin H).

PubMed

Yokoya, Masashi; Kobayashi, Keiichiro; Sato, Mitsuhiro; Saito, Naoki

2015-08-06

The first total synthesis of (±)-renieramycin I, which was isolated from the Indian bright blue sponge Haliclona cribricutis, is described. The key step is the selenium oxide oxidation of pentacyclic bis-p-quinone derivative (3) stereo- and regioselectively. We also report a large-scale synthesis of cribrostatin 4 (renieramycin H) via the C3-C4 double bond formation in an early stage based on the Avendaño's protocol, from readily available 1-acetyl-3-(3-methyl-2,4,5-trimethylphenyl)methyl-piperazine-2,5-dione (8) in 18 steps (8.3% overall yield). The synthesis provides unambiguous evidence supporting the original structure of renieramycin I.

[Biological activity of selenorganic compounds at heavy metal salts intoxication].

PubMed

Rusetskaya, N Y; Borodulin, V B

2015-01-01

Possible mechanisms of the antitoxic action of organoselenium compounds in heavy metal poisoning have been considered. Heavy metal toxicity associated with intensification of free radical oxidation, suppression of the antioxidant system, damage to macromolecules, mitochondria and the genetic material can cause apoptotic cell death or the development of carcinogenesis. Organic selenium compounds are effective antioxidants during heavy metal poisoning; they exhibit higher bioavailability in mammals than inorganic ones and they are able to activate antioxidant defense, bind heavy metal ions and reactive oxygen species formed during metal-induced oxidative stress. One of promising organoselenium compounds is diacetophenonyl selenide (DAPS-25), which is characterized by antioxidant and antitoxic activity, under conditions including heavy metal intoxication.

Expulsion of selenium/protein nanoparticles through vesicle-like structures by Saccharomyces cerevisiae under microaerophilic environment.

PubMed

Zhang, Liang; Li, Daping; Gao, Ping

2012-12-01

Nano-selenium/protein is a kind of lower toxic supplement to human. Many microorganisms can reduce selenite/selenate to intracellular or extracellular selenium nanoparticles. This study examined the influence of dissolved oxygen on the expulsion of extracellular selenium/protein produced in Saccharomyces cerevisiae. More of the added selenite was reduced to extracellular selenium nanoparticles by yeast cells only under oxygen-limited condition than under aerobic or anaerobic condition. For the first time, we evidenced that selenium/protein nanoparticles synthesized in vivo were transported out of the cells by vesicle-like structures under microaerophilic environment. The characterizations of the extracellular spherical selenium/protein nanoparticles were also examined by SEM, TEM, EDX and FTIR.

Selenium Recycling in the United States in 2004

USGS Publications Warehouse

George, Micheal W.; Wagner, Lorie A.

2009-01-01

The vast majority of selenium consumption in the United States is in dissipative uses, such as alloys, animal feeds, fertilizers, glass decolorizer, and pigments. The nondissipative use as a photoreceptor for xerographic copiers is declining. As a result of a lack of a substantial supply of selenium-containing scrap, there are no longer selenium recycling facilities in the United States. Selenium-containing materials collected for recycling, primarily selenium-containing photocopier drums, are exported for processing in other countries. Of the estimated 350 metric tons (t) of selenium products that went to the U.S. market in 2004, an estimated 300 t went to dissipative uses. An estimated 4 t was recovered from old scrap and exported for recycling.

Selenium species in selenium fortified dietary supplements.

PubMed

Niedzielski, Przemyslaw; Rudnicka, Monika; Wachelka, Marcin; Kozak, Lidia; Rzany, Magda; Wozniak, Magdalena; Kaskow, Zaneta

2016-01-01

This article presents a study of dietary supplements available on the Polish market. The supplements comprised a large group of products with selenium content declared by the producer. The study involved determination of dissolution time under different conditions and solubility as well as content and speciation of selenium. The total content was determined as well as organic selenium and the inorganic forms Se(IV) and Se(VI). The organic selenium content was calculated as the difference between total Se and inorganic Se. The values obtained were compared with producers' declarations. The work is the first such study of selenium supplements available on the market of an EU Member State. Copyright © 2015 Elsevier Ltd. All rights reserved.

Isolation and reversible dimerization of a selenium-selenium three-electron σ-bond.

PubMed

Zhang, Senwang; Wang, Xingyong; Su, Yuanting; Qiu, Yunfan; Zhang, Zaichao; Wang, Xinping

2014-06-11

Three-electron σ-bonding that was proposed by Linus Pauling in 1931 has been recognized as important in intermediates encountered in many areas. A number of three-electron bonding systems have been spectroscopically investigated in the gas phase, solution and solid matrix. However, X-ray diffraction studies have only been possible on simple noble gas dimer Xe∴Xe and cyclic framework-constrained N∴N radical cations. Here, we show that a diselena species modified with a naphthalene scaffold can undergo one-electron oxidation using a large and weakly coordinating anion, to afford a room-temperature-stable radical cation containing a Se∴Se three-electron σ-bond. When a small anion is used, a reversible dimerization with phase and marked colour changes is observed: radical cation in solution (blue) but diamagnetic dimer in the solid state (brown). These findings suggest that more examples of three-electron σ-bonds may be stabilized and isolated by using naphthalene scaffolds together with large and weakly coordinating anions.

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

PubMed

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.

Selenium Deficiency Influences the Expression of Selenoproteins and Inflammatory Cytokines in Chicken Aorta Vessels.

PubMed

Du, Qiang; Yao, Haidong; Yao, Linlin; Zhang, Ziwei; Lei, Xingen; Xu, Shiwen

2016-10-01

Selenium deficiency is known to cause cardiovascular diseases. However, the role of Se deficiency in causing oxidative damage and inflammation injury to the aorta vessels of chickens is not well known. In the present study, 180 1-day-old chickens were randomly divided into two groups, a low-Se group (L group) and a control-Se group (C group). The messenger RNA (mRNA) levels of 25 selenoproteins, the mRNA and protein expression levels of inflammatory cytokines (including NF-κB, TNF-α, COX-2, and PTGES), and the antioxidant levels in chicken aorta vessels were examined. The results showed that the mRNA levels of 25 selenoproteins and the activity of Gpx were decreased, while the mRNA and protein expression levels of inflammatory cytokines and the MDA content were increased by Se deficiency in chicken aorta vessels. The data from the present study indicated that Se deficiency decreases the expression of selenoproteins, reduces antioxidant function, and increases the expression of inflammatory factors in chicken aorta vessels.

Selenoprotein H is an essential regulator of redox homeostasis that cooperates with p53 in development and tumorigenesis.

PubMed

Cox, Andrew G; Tsomides, Allison; Kim, Andrew J; Saunders, Diane; Hwang, Katie L; Evason, Kimberley J; Heidel, Jerry; Brown, Kristin K; Yuan, Min; Lien, Evan C; Lee, Byung Cheon; Nissim, Sahar; Dickinson, Bryan; Chhangawala, Sagar; Chang, Christopher J; Asara, John M; Houvras, Yariv; Gladyshev, Vadim N; Goessling, Wolfram

2016-09-20

Selenium, an essential micronutrient known for its cancer prevention properties, is incorporated into a class of selenocysteine-containing proteins (selenoproteins). Selenoprotein H (SepH) is a recently identified nucleolar oxidoreductase whose function is not well understood. Here we report that seph is an essential gene regulating organ development in zebrafish. Metabolite profiling by targeted LC-MS/MS demonstrated that SepH deficiency impairs redox balance by reducing the levels of ascorbate and methionine, while increasing methionine sulfoxide. Transcriptome analysis revealed that SepH deficiency induces an inflammatory response and activates the p53 pathway. Consequently, loss of seph renders larvae susceptible to oxidative stress and DNA damage. Finally, we demonstrate that seph interacts with p53 deficiency in adulthood to accelerate gastrointestinal tumor development. Overall, our findings establish that seph regulates redox homeostasis and suppresses DNA damage. We hypothesize that SepH deficiency may contribute to the increased cancer risk observed in cohorts with low selenium levels.

Selenium nanoparticles fabricated in Undaria pinnatifida polysaccharide solutions induce mitochondria-mediated apoptosis in A375 human melanoma cells.

PubMed

Chen, Tianfeng; Wong, Yum-Shing; Zheng, Wenjie; Bai, Yan; Huang, Liang

2008-11-15

Selenium nanoparticle (Nano-Se) is a novel Se species with novel biological activities and low toxicity. In the present study, we demonstrated a simple method for synthesis of size-controlled Nano-Se by adding Undaria pinnatifida polysaccharides to the redox system of selenite and ascorbic acid. A panel of four human cancer cell lines was shown to be susceptible to Nano-Se, with IC(50) values ranging from 3.0 to 14.1 microM. Treatment of A375 human melanoma cells with the Nano-Se resulted in dose-dependent cell apoptosis as indicated by DNA fragmentation and phosphatidylserine translocation. Further investigation on intracellular mechanisms found that Nano-Se treatment triggered apoptotic cell death in A375 cells with the involvement of oxidative stress and mitochondrial dysfunction. Our results suggest that Nano-Se may be a candidate for further evaluation as a chemopreventive and chemotherapeutic agent for human cancers, especially melanoma cancer.

Antitumoural Sulphur and Selenium Heteroaryl Compounds: Thermal Characterization and Stability Evaluation.

PubMed

Alcolea, Verónica; Garnica, Pablo; Palop, Juan A; Sanmartín, Carmen; González-Peñas, Elena; Durán, Adrián; Lizarraga, Elena

2017-08-08

The physicochemical properties of a compound play a crucial role in the cancer development process. In this context, polymorphism can become an important obstacle for the pharmaceutical industry because it frequently leads to the loss of therapeutic effectiveness of some drugs. Stability under manufacturing conditions is also critical to ensure no undesired degradations or transformations occur. In this study, the thermal behaviour of 40 derivatives of a series of sulphur and selenium heteroaryl compounds with potential antitumoural activity were studied. In addition, the most promising cytotoxic derivatives were analysed by a combination of differential scanning calorimetry, X-ray diffraction and thermogravimetric techniques in order to investigate their polymorphism and thermal stability. Moreover, stability under acid, alkaline and oxidative media was tested. Degradation under stress conditions as well as the presence of polymorphism was found for the compounds VA6E and VA7J, which might present a hurdle to carrying on with formulation. On the contrary, these obstacles were not found for derivative VA4J.

Defining the Optimal Selenium Dose for Prostate Cancer Risk Reduction: Insights from the U-Shaped Relationship Between Selenium Status, DNA Damage, and Apoptosis

USDA-ARS?s Scientific Manuscript database

Our work in dogs has revealed a U-shaped dose response between selenium status and prostatic DNA damage that remarkably parallels the relationship between dietary selenium and prostate cancer risk in men, suggesting that more selenium is not necessarily better. Herein, we extend this canine work to ...

Is selenium supplementation in autoimmune thyroid diseases justified?

PubMed

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.

Microarray Data Mining for Potential Selenium Targets in Chemoprevention of Prostate Cancer

PubMed Central

ZHANG, HAITAO; DONG, YAN; ZHAO, HONGJUAN; BROOKS, JAMES D.; HAWTHORN, LESLEYANN; NOWAK, NORMA; MARSHALL, JAMES R.; GAO, ALLEN C.; IP, CLEMENT

2008-01-01

Background A previous clinical trial showed that selenium supplementation significantly reduced the incidence of prostate cancer. We report here a bioinformatics approach to gain new insights into selenium molecular targets that might be relevant to prostate cancer chemoprevention. Materials and Methods We first performed data mining analysis to identify genes which are consistently dysregulated in prostate cancer using published datasets from gene expression profiling of clinical prostate specimens. We then devised a method to systematically analyze three selenium microarray datasets from the LNCaP human prostate cancer cells, and to match the analysis to the cohort of genes implicated in prostate carcinogenesis. Moreover, we compared the selenium datasets with two datasets obtained from expression profiling of androgen-stimulated LNCaP cells. Results We found that selenium reverses the expression of genes implicated in prostate carcinogenesis. In addition, we found that selenium could counteract the effect of androgen on the expression of a subset obtained from androgen-regulated genes. Conclusions The above information provides us with a treasure of new clues to investigate the mechanism of selenium chemoprevention of prostate cancer. Furthermore, these selenium target genes could also serve as biomarkers in future clinical trials to gauge the efficacy of selenium intervention. PMID:18548127

Selenium and the control of thyroid hormone metabolism.

PubMed

Köhrle, Josef

2005-08-01

Thyroid hormone synthesis, metabolism and action require adequate availability of the essential trace elements iodine and selenium, which affect homeostasis of thyroid hormone-dependent metabolic pathways. The three selenocysteine-containing iodothyronine deiodinases constitute a novel gene family. Selenium is retained and deiodinase expression is maintained at almost normal levels in the thyroid gland, the brain and several other endocrine tissues during selenium deficiency, thus guaranteeing adequate local and systemic levels of the active thyroid hormone T(3). Due to their low tissue concentrations and their mRNA SECIS elements deiodinases rank high in the cellular and tissue-specific hierarchy of selenium distribution among various selenoproteins. While systemic selenium status and expression of abundant selenoproteins (glutathione peroxidase or selenoprotein P) is already impaired in patients with cancer, disturbed gastrointestinal resorption, unbalanced nutrition or patients requiring intensive care treatment, selenium-dependent deiodinase function might still be adequate. However, disease-associated alterations in proinflammatory cytokines, growth factors, hormones and pharmaceuticals modulate deiodinase isoenzyme expression independent from altered selenium status and might thus pretend causal relationships between systemic selenium status and altered thyroid hormone metabolism. Limited or inadequate supply of both trace elements, iodine and selenium, leads to complex rearrangements of thyroid hormone metabolism enabling adaptation to unfavorable conditions.

Reproductive status of western mosquitofish inhabiting selenium- contaminated waters in the Grassland Water District, Merced County, California

USGS Publications Warehouse

Saiki, M.K.; Martin, B.A.; May, T.W.

2004-01-01

This study was implemented to determine if western mosquitofish (Gambusia affinis) populations in the Grassland Water District suffer from impaired reproduction because of seleniferous inflows of agricultural drainwater from the Grassland Bypass Project. During June to July 2001, laboratory trials with pregnant female fish collected from two seleniferous treatment sites exposed to selenium-laden drainwater and two nonseleniferous reference sites yielded fry that averaged >96% survival at birth. In addition, none of the newborn fry exhibited evidence of teratogenesis, a typical consequence of selenium toxicity. Chemical analysis of postpartum female fish and their newborn fry indicated that mosquitofish from seleniferous sites accumulated relatively high body burdens of selenium (3.96 to 17.5 μg selenium/g in postpartum female fish and 5.35 to 29.2 μg selenium/g in their fry), whereas those from nonseleniferous sites contained lower body burdens (0.40 to 2.72 μg selenium/g in postpartum female fish and 0.61 to 4.68 μg selenium/g in their fry). Collectively, these results strongly suggest that mosquitofish inhabiting selenium-contaminated waters are not experiencing adverse reproductive effects at current levels of selenium exposure.

Does selenium supplementation affect thyroid function? Results from a randomized, controlled, double-blinded trial in a Danish population.

PubMed

Winther, Kristian Hillert; Bonnema, Steen Joop; Cold, Frederik; Debrabant, Birgit; Nybo, Mads; Cold, Søren; Hegedüs, Laszlo

2015-06-01

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. 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 or matching yeast-based placebo tablets (n=126). A total of 361 participants, equally distributed across treatment groups, completed the 5-year intervention period. Plasma samples were analyzed for selenium and serum samples for TSH, free triiodothyronine (FT3), and free thyroxine (FT4) at baseline, and after 6 months, and 5 years of supplementation. Plasma selenium concentrations increased significantly and dose-dependently in treatment groups receiving selenium (P<0.001). Serum TSH and FT4 concentrations decreased significantly and dose-dependently by 0.066 mIU/l (P=0.010) and 0.11 pmol/l (P=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. In euthyroid subjects, selenium supplementation minutely and dose-dependently affects thyroid function, when compared with placebo, by decreasing serum TSH and FT4 concentrations. Based on these findings, selenium supplementation is not warranted under conditions of marginal selenium deficiency. However, a role for selenium supplementation in the treatment of autoimmune thyroid diseases is still unresolved. © 2015 European Society of Endocrinology.

Uptake and speciation of selenium in garlic cultivated in soil amended with symbiotic fungi (mycorrhiza) and selenate.

PubMed

Larsen, Erik H; Lobinski, Ryszard; Burger-Meÿer, Karin; Hansen, Marianne; Ruzik, Rafal; Mazurowska, Lena; Rasmussen, Peter Have; Sloth, Jens J; Scholten, Olga; Kik, Chris

2006-07-01

The scope of the work was to investigate the influence of selenate fertilisation and the addition of symbiotic fungi (mycorrhiza) to soil on selenium and selenium species concentrations in garlic. The selenium species were extracted from garlic cultivated in experimental plots by proteolytic enzymes, which ensured liberation of selenium species contained in peptides or proteins. Separate extractions using an aqueous solution of enzyme-deactivating hydroxylamine hydrochloride counteracted the possible degradation of labile selenium species by enzymes (such as alliinase) that occur naturally in garlic. The selenium content in garlic, which was analysed by ICP-MS, showed that addition of mycorrhiza to the natural soil increased the selenium uptake by garlic tenfold to 15 microg g(-1) (dry mass). Fertilisation with selenate and addition of mycorrhiza strongly increased the selenium content in garlic to around one part per thousand. The parallel analysis of the sample extracts by cation exchange and reversed-phase HPLC with ICP-MS detection showed that gamma-glutamyl-Se-methyl-selenocysteine amounted to 2/3, whereas methylselenocysteine, selenomethionine and selenate each amounted to a few percent of the total chromatographed selenium in all garlic samples. Se-allyl-selenocysteine and Se-propyl-selenocysteine, which are selenium analogues of biologically active sulfur-containing amino acids known to occur in garlic, were searched for but not detected in any of the extracts. The amendment of soil by mycorrhiza and/or by selenate increased the content of selenium but not the distribution of detected selenium species in garlic. Finally, the use of two-dimensional HPLC (size exclusion followed by reversed-phase) allowed the structural characterisation of gamma-glutamyl-Se-methyl-selenocysteine and gamma-glutamyl-Se-methyl-selenomethionine in isolated chromatographic fractions by quadrupole time-of-flight mass spectrometry.

[Selenium supplementation trials for cancer prevention and the subsequent risk of type 2 diabetes mellitus: selenium and vitamin E cancer prevention trial and after].

PubMed

Koyama, Hiroshi; Mutakin; Abdulah, Rizky; Yamazaki, Chiho; Kameo, Satomi

2013-01-01

The essential trace element selenium has long been considered to exhibit cancer-preventive, antidiabetic and insulin-mimetic properties. However, recent epidemiological studies have indicated that supranutritional selenium intake and high plasma selenium levels are not necessarily preventive against cancer, and are possible risk factors for developing type 2 diabetes mellitus. The results of the SELECT, Selenium and Vitamin E Cancer Prevention Trial, in which it is hypothesized that the supplementations with selenium and/or vitamin E decrease the prostate cancer incidence among healthy men in the U.S., showed that the supplementation did not prevent the development of prostate cancer and that the incidence of newly diagnosed type 2 diabetes mellitus increased among the selenium-supplemented participants. The Nutritional Prevention of Cancer (NPC) trial showed a decreased risk of prostate cancer among participants taking 200 μg of selenium daily for 7.7 years. However, the results of the NPC trial also showed an increased risk of type 2 diabetes mellitus in the participants with plasma selenium levels in the top tertile at the start of the study. Recently, the association of serum selenium with adipocytokines, such as TNF-α, VCAM-1, leptin, FABP-4, and MCP-1, has been observed. Selenoprotein P has been reported to associated with adiponectin, which suggests new roles of selenoprotein P in cellular energy metabolism, possibly leading to the increased risk of type 2 diabetes mellitus and also the development of cancer. Further studies are required to elucidate the relationship between selenium and adipocytokines and the role of selenoprotein P in the development of type 2 diabetes mellitus and cancer at high levels of selenium.

Effect of dietary selenium and omega-3 fatty acids on muscle composition and quality in broilers

PubMed Central

Haug, Anna; Eich-Greatorex, Susanne; Bernhoft, Aksel; Wold, Jens P; Hetland, Harald; Christophersen, Olav A; Sogn, Trine

2007-01-01

Background Human health may be improved if dietary intakes of selenium and omega-3 fatty acids are increased. Consumption of broiler meat is increasing, and the meat content of selenium and omega-3 fatty acids are affected by the composition of broiler feed. A two-way analyses of variance was used to study the effect of feed containing omega-3 rich plant oils and selenium enriched yeast on broiler meat composition, antioxidation- and sensory parameters. Four different wheat-based dietary treatments supplemented with 5% rapeseed oil or 4% rapeseed oil plus 1% linseed oil, and either 0.50 mg selenium or 0.84 mg selenium (organic form) per kg diet was fed to newly hatched broilers for 22 days. Results The different dietary treatments gave distinct different concentrations of selenium and fatty acids in thigh muscle; one percent linseed oil in the diet increased the concentration of the omega-3 fatty acids 18:3, 20:5 and 22:5, and 0.84 mg selenium per kg diet gave muscle selenium concentration at the same level as is in fish muscle (0.39 mg/kg muscle). The high selenium intake also resulted in increased concentration of the long-chain omega-3 fatty acids EPA (20:5), DPA (22:5) and DHA (22:6), thus it may be speculated if high dietary selenium might have a role in increasing the concentration of EPA, DPA and DHA in tissues after intake of plant oils contning omega-3 fatty acids. Conclusion Moderate modifications of broiler feed may give a healthier broiler meat, having increased content of selenium and omega-3 fatty acids. High intakes of selenium (organic form) may increase the concentration of very long-chain omega-3 fatty acids in muscle. PMID:17967172

Detailed study of selenium in soil, water, bottom sediment, and biota in the Sun River Irrigation Project, Freezout Lake Wildlife Management Area, and Benton Lake National Wildlife Refuge, west-central Montana, 1990-92

USGS Publications Warehouse

Nimick, D.A.; Lambing, J.H.; Palawski, D.U.; Malloy, J.C.

1996-01-01

Selenium and other constituents are adversely affecting water quality and creating a potential hazard to wildlife in several areas of the Sun River Irrigation Project, Freezout Lake Wildlife Management Area, and Benton Lake National Wildlife Refuge in west-central Montana. Selenium derived from Cretaceous shale and Tertiary and Quaternary deposits containing shale detritus is transported in the oxic shallow ground-water systems. At Freezout Lake Wildlife Management Area, drainage from irrigated glacial deposits is the primary source of selenium; drainage from non-irrigated farmland is a significant source locally. Benton Lake generally receives more selenium from natural runoff from its non-irrigated basin than from the trans-basin diversion of irrigation return flow. Selenium has accumulated in aquatic plants and invertebrates, fish, and water birds, particularly in wetlands that receive the largest selenium loads. Although selenium residues in biological tissue from some wetland units exceeded biological risk levels, water-bird reproduction generally has not been impaired. The highest selenium residues in biota commonly occurred in samples from Priest Butte Lakes, which also had the highest selenium concentration in wetland water. Selenium concentrations in all invertebrate samples from Priest Butte Lakes and the south end of Freezeout Lake exceeded the critical dietary threshold for water birds. Selenium delivered to wetlands accumulates in bottom sediment, predominantly in near-shore areas. Potential impacts to water quality, and presumably biota, may be greatest near the mouths of inflows. Most selenium delivered to wetlands will continue to accumulate in bottom sediment and biota.

Preliminary assessment of sources, distribution, and mobility of selenium in the San Joaquin Valley, California

USGS Publications Warehouse

Gilliom, R.J.

1989-01-01

Selenium in tile drain water from parts of the western San Joaquin Valley, California, has adversely affected fish and waterfowl where drain water was impounded. Soils in these drained areas were derived from Coast Range marine sedimentary formations, were naturally saline and probably contained abundant soluble selenium. Decades of irrigation have redistributed the most soluble forms of selenium from the soil into groundwater and have caused the water table to rise 1 to 4 ft/year. Selenium in shallow groundwater has been further concentrated because of evapotranspiration. The rising water table has caused a large area of farmland to require artificial drainage of groundwater that contains high concentrations of selenium. The present areal distribution of selenium in shallow groundwater reflects the natural distribution of saline soils. The depth distribution of selenium in groundwater reflects the history of irrigation. The highest concentrations of selenium in groundwater (50 to more than 1,000 micrograms/L) are in a zone of variable thickness located between 20 and 150 ft below the water table. The toxic water in this zone was recharged during the first few decades of irrigation. The large volume of high selenium groundwater makes it desirable to leave this water where it is, rather than bring it to the land surface or allow it to move into parts of the aquifer that may be used for water supply. Selenium concentrations in the San Joaquin River depend on the magnitude of the selenium load from drain water and dilution by water with low concentrations of selenium from all other sources of streamflow. The San Joaquin Valley is a regional-scale example of how manipulation of the hydrologic system can cause water quality problems if naturally occurring toxic substances are mobilized. (USGS)

Selenium Levels in Serum, Red Blood Cells, and Cerebrospinal Fluid of Alzheimer's Disease Patients: A Report from the Australian Imaging, Biomarker & Lifestyle Flagship Study of Ageing (AIBL).

PubMed

Cardoso, Bárbara R; Hare, Dominic J; Bush, Ashley I; Li, Qiao-Xin; Fowler, Christopher J; Masters, Colin L; Martins, Ralph N; Ganio, Katherine; Lothian, Amber; Mukherjee, Soumya; Kapp, Eugene A; Roberts, Blaine R

2017-01-01

Selenium (Se) protects cells against oxidative stress damage through a range of bioactive selenoproteins. Increased oxidative stress is a prominent feature of Alzheimer's disease (AD), and previous studies have shown that Se deficiency is associated with age-related cognitive decline. In this study, we assessed Se status in different biofluids from a subgroup of participants in the Australian Imaging, Biomarkers and Lifestyle Flagship Study of Ageing. As Se in humans can either be an active component of selenoproteins or inactive via non-specific incorporation into other proteins, we used both size exclusion chromatography-inductively coupled plasma-mass spectrometry (SEC-ICP-MS) and tandem mass spectrometry to characterize selenoproteins in serum. We observed no differences in total Se concentration in serum or cerebrospinal fluid of AD subjects compared to mildly cognitively impairment patients and healthy controls. However, Se levels in erythrocytes were decreased in AD compared to controls. SEC-ICP-MS analysis revealed a dominant Se-containing fraction. This fraction was subjected to standard protein purification and a bottom-up proteomics approach to confirm that the abundant Se in the fraction was due, in part, to selenoprotein P. The lack of change in the Se level is at odds with our previous observations in a Brazilian population deficient in Se, and we attribute this to the Australian cohort being Se-replete.

Ameliorative effect of vitamin E and selenium against oxidative stress induced by sodium azide in liver, kidney, testis and heart of male mice.

PubMed

Hamza, Reham Z; Al-Harbi, Mohammad S; El-Shenawy, Nahla S

2017-07-01

The study purported to define the effects of daily administration of vitamin E (Vit E) and selenium (Se) on antioxidant enzyme activity in mice treated with high doses of sodium azide (SA). Male mice were randomly split into nine groups. Groups 1, 2 and 3 were injected daily with saline, Vit E, and Se, respectively, while groups 4, 5 and 6 administrated with different doses of SA (low, medium and high, respectively). The mice in groups 7, 8 and 9 received 100mg/kg Vit E, 17.5mg/kg Se, and a combination of Vit E and Se, respectively before the SA-treatment. Hepatic, renal, testis and heart, antioxidant enzymes as well as levels of lipid peroxidation and total antioxidant capacity levels were determined. Vit E alone affected on the antioxidant parameters of the examined tissues. Se had a preventive effect on the decrease of antioxidant parameters caused by SA and improved the diminished activities of all of them. The study demonstrates that a high dose of SA may alter the effects of normal level antioxidant/oxidative status of male mice and that Se is effective in reducing the SA-damage. Se acts as a synergistic agent with the effect of Vit E in various damaged caused by SA. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Selenite induces posttranscriptional blockade of HLA-E expression and sensitizes tumor cells to CD94/NKG2A-positive NK cells.

PubMed

Enqvist, Monika; Nilsonne, Gustav; Hammarfjord, Oscar; Wallin, Robert P A; Björkström, Niklas K; Björnstedt, Mikael; Hjerpe, Anders; Ljunggren, Hans-Gustaf; Dobra, Katalin; Malmberg, Karl-Johan; Carlsten, Mattias

2011-10-01

CD94/NKG2A is an inhibitory receptor that controls the activity of a large proportion of human NK cells following interactions with the nonclassical HLA class Ib molecule HLA-E expressed on target cells. In this study, we show that selenite (SeO(3)(2-)), an inorganic selenium compound, induces an almost complete loss of cell surface expression of HLA-E on tumor cells of various origins. Selenite abrogated the HLA-E expression at a posttranscriptional level, since selenite exposure led to a dose-dependent decrease in cellular HLA-E protein expression whereas the mRNA levels remained intact. The loss of HLA-E expression following selenite treatment was associated with decreased levels of intracellular free thiols in the tumor cells, suggesting that the reduced HLA-E protein synthesis was caused by oxidative stress. Indeed, HLA-E expression and the level of free thiols remained intact following treatment with selenomethionine, a selenium compound that does not generate oxidative stress. Loss of HLA-E expression, but not of total HLA class I expression, on tumor cells resulted in increased susceptibility to CD94/NK group 2A-positive NK cells. Our results suggest that selenite may be used to potentiate the anti-tumor cytotoxicity in settings of NK cell-based immunotherapies.

Selenium ameliorates isotretinoin-induced liver injury and dyslipidemia via antioxidant effect in rats.

PubMed

Saied, Nashwa Mostafa; Hamza, Alaaeldin Ahmed

2014-09-01

Isotretinoin (Iso) is a widely used retinoid for the treatment of dermatologic conditions. Although it has broad side effects, there is no well-designed study about preventive effects against its hepatic toxicity. This study was undertaken to evaluate the protective effect of selenium (Se) against Iso-induced hepatotoxicity in Wistar rats. Animals were divided into four groups. The first group served as control. The second, third and fourth groups received Se, Iso and Se & Iso, respectively, for 28 days. Se was administered daily orally at a dose of 50 µg / 100 g body weight. Iso was given daily orally at a dose of 0.75 mg/ 100 g /day in olive oil. Iso caused significant increases in serum levels of alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, cholesterol, triglycerides, and high-density lipids content. Animals also showed significant rise in thiobarbituric acid reacting substance and nitric oxide content with concomitant decrease in reduced glutathione content and the antioxidant enzyme activities of superoxide dismutase and catalase in liver tissue after Iso exposure. Se administration produced a significant protection against the hepatotoxic effects of Iso and markedly alleviated alterations in these parameters. The results obtained herein clearly indicate that Iso causes induction of oxidative stress and the co-administration of Iso and Se provides protection against Iso-induced liver injury.

Hydrological and geochemical investigations of selenium behavior at Kesterson Reservoir. Progress report, October 1, 1994--September 30, 1996

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zawislanski, P.; Tokunaga, T.; Benson, S.M.

1997-10-01

This report describes research relevant to selenium (Se) speciation, fractionation, physical redistribution, reduction and oxidation, and spatial distribution as related to Kesterson Reservoir. The work was carried out by scientists and engineers from the Earth Sciences Division of the Lawrence Berkeley Laboratory over a two year period from October 1994 to September 1996. Much of the focus of this research was on long-term, Reservoir-wide changes in Se concentrations and distribution; estimation and prediction of the physical extent ephemeral pools; and the quantification and prediction of Se levels in ephemeral pools waters and underlying sediments. Chapter 2 contains descriptions of fieldmore » monitoring of soil processes. In Section 2.1, elevated Se concentrations observed in groundwater in the northern part of Pond 9 are investigated. The past removal of the original surface soil in the northern Pond 9 area resulted in the enhancement of Se transport into the shallow groundwater in this area. Removal of the most organic-rich surface soil horizon left the remaining profile with a lower capacity to generate and sustain reducing conditions needed to immobilize Se. Furthermore, removal of the lower permeability surface soil left the remaining profile more hydraulically conductive since sands are encountered at fairly shallow depths. These conditions result in Se remaining oxidized down to the 2.00 m depth throughout the year.« less

The effect of sulfate on selenate bioaccumulation in two freshwater primary producers: A duckweed (Lemna minor) and a green alga (Pseudokirchneriella subcapitata).

PubMed

Lo, Bonnie P; Elphick, James R; Bailey, Howard C; Baker, Josh A; Kennedy, Christopher J

2015-12-01

Predicting selenium bioaccumulation is complicated because site-specific conditions, including the ionic composition of water, affect the bioconcentration of inorganic selenium into the food web. Selenium tissue concentrations were measured in Lemna minor and Pseudokirchneriella subcapitata following exposure to selenate and sulfate. Selenium accumulation differed between species, and sulfate reduced selenium uptake in both species, indicating that ionic constituents, in particular sulfate, are important in modifying selenium uptake by primary producers. © 2015 SETAC.

Total selenium in irrigation drain inflows to the Salton Sea, California, April 2009

USGS Publications Warehouse

May, Thomas W.; Walther, Michael J.; Saiki, Michael K.; Brumbaugh, William G.

2009-01-01

This report presents the results for the final sampling period (April 2009) of a 4-year monitoring program to characterize selenium concentrations in selected irrigation drains flowing into the Salton Sea, California. Total selenium and total suspended solids were determined in water samples. Total selenium, percent total organic carbon, and particle size were determined in sediments. Mean total selenium concentrations in water ranged from 0.98 to 22.9 micrograms per liter. Total selenium concentrations in sediment ranged from 0.078 to 5.0 micrograms per gram dry weight.

Novel MoSe2 hierarchical microspheres for applications in visible-light-driven advanced oxidation processes.

PubMed

Dai, Chu; Qing, Enping; Li, Yong; Zhou, Zhaoxin; Yang, Chao; Tian, Xike; Wang, Yanxin

2015-12-21

Advanced oxidation processes as a green technology have been adopted by combining the semiconductor catalyst MoSe2 with H2O2 under visible radiation. And novel three-dimensional self-assembled molybdenum diselenide (MoSe2) hierarchical microspheres from nanosheets were produced by using organic, selenium cyanoacetic acid sodium (NCSeCH2COONa) as the source of Se. The obtained products possess good crystallinity and present hierarchical structures with the average diameter of 1 μm. The band gap of MoSe2 microspheres is 1.68 eV and they present excellent photocatalytic activity under visible light irradiation in the MoSe2-H2O2 system. This effective photocatalytic mechanism was investigated in this study and can be attributed to visible-light-driven advanced oxidation processes.

Biochemical and biophysical characterization of the selenium-binding and reducing site in Arabidopsis thaliana homologue to mammals selenium-binding protein 1.

PubMed

Schild, Florie; Kieffer-Jaquinod, Sylvie; Palencia, Andrés; Cobessi, David; Sarret, Géraldine; Zubieta, Chloé; Jourdain, Agnès; Dumas, Renaud; Forge, Vincent; Testemale, Denis; Bourguignon, Jacques; Hugouvieux, Véronique

2014-11-14

The function of selenium-binding protein 1 (SBP1), present in almost all organisms, has not yet been established. In mammals, SBP1 is known to bind the essential element selenium but the binding site has not been identified. In addition, the SBP family has numerous potential metal-binding sites that may play a role in detoxification pathways in plants. In Arabidopsis thaliana, AtSBP1 over-expression increases tolerance to two toxic compounds for plants, selenium and cadmium, often found as soil pollutants. For a better understanding of AtSBP1 function in detoxification mechanisms, we investigated the chelating properties of the protein toward different ligands with a focus on selenium using biochemical and biophysical techniques. Thermal shift assays together with inductively coupled plasma mass spectrometry revealed that AtSBP1 binds selenium after incubation with selenite (SeO3(2-)) with a ligand to protein molar ratio of 1:1. Isothermal titration calorimetry confirmed the 1:1 stoichiometry and revealed an unexpectedly large value of binding enthalpy suggesting a covalent bond between selenium and AtSBP1. Titration of reduced Cys residues and comparative mass spectrometry on AtSBP1 and the purified selenium-AtSBP1 complex identified Cys(21) and Cys(22) as being responsible for the binding of one selenium. These results were validated by site-directed mutagenesis. Selenium K-edge x-ray absorption near edge spectroscopy performed on the selenium-AtSBP1 complex demonstrated that AtSBP1 reduced SeO3(2-) to form a R-S-Se(II)-S-R-type complex. The capacity of AtSBP1 to bind different metals and selenium is discussed with respect to the potential function of AtSBP1 in detoxification mechanisms and selenium metabolism. © 2014 by The American Society for Biochemistry and Molecular Biology, Inc.

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

PubMed Central

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

Biochemical and Biophysical Characterization of the Selenium-binding and Reducing Site in Arabidopsis thaliana Homologue to Mammals Selenium-binding Protein 1*

PubMed Central

Schild, Florie; Kieffer-Jaquinod, Sylvie; Palencia, Andrés; Cobessi, David; Sarret, Géraldine; Zubieta, Chloé; Jourdain, Agnès; Dumas, Renaud; Forge, Vincent; Testemale, Denis; Bourguignon, Jacques; Hugouvieux, Véronique

2014-01-01

The function of selenium-binding protein 1 (SBP1), present in almost all organisms, has not yet been established. In mammals, SBP1 is known to bind the essential element selenium but the binding site has not been identified. In addition, the SBP family has numerous potential metal-binding sites that may play a role in detoxification pathways in plants. In Arabidopsis thaliana, AtSBP1 over-expression increases tolerance to two toxic compounds for plants, selenium and cadmium, often found as soil pollutants. For a better understanding of AtSBP1 function in detoxification mechanisms, we investigated the chelating properties of the protein toward different ligands with a focus on selenium using biochemical and biophysical techniques. Thermal shift assays together with inductively coupled plasma mass spectrometry revealed that AtSBP1 binds selenium after incubation with selenite (SeO32−) with a ligand to protein molar ratio of 1:1. Isothermal titration calorimetry confirmed the 1:1 stoichiometry and revealed an unexpectedly large value of binding enthalpy suggesting a covalent bond between selenium and AtSBP1. Titration of reduced Cys residues and comparative mass spectrometry on AtSBP1 and the purified selenium-AtSBP1 complex identified Cys21 and Cys22 as being responsible for the binding of one selenium. These results were validated by site-directed mutagenesis. Selenium K-edge x-ray absorption near edge spectroscopy performed on the selenium-AtSBP1 complex demonstrated that AtSBP1 reduced SeO32− to form a R-S-Se(II)-S-R-type complex. The capacity of AtSBP1 to bind different metals and selenium is discussed with respect to the potential function of AtSBP1 in detoxification mechanisms and selenium metabolism. PMID:25274629

Biological alkylation and colloid formation of selenium in methanogenic UASB reactors.

PubMed

Lenz, Markus; Smit, Martijn; Binder, Patrick; van Aelst, Adriaan C; Lens, Piet N L

2008-01-01

Bioalkylation and colloid formation of selenium during selenate removal in upflow anaerobic sludge bed (UASB) bioreactors was investigated. The mesophilic (30 degrees C) UASB reactor (pH = 7.0) was operated for 175 d with lactate as electron donor at an organic loading rate of 2 g COD L(-1) d(-1) and a selenium loading rate of 3.16 mg Se L(-1) d(-1). Combining sequential filtration with ion chromatographic analysis for selenium oxyanions and solid phase micro extraction gas chromatography mass spectrometry (SPME-GC-MS) for alkylated selenium compounds allowed to entirely close the selenium mass balance in the liquid phase for most of the UASB operational runtime. Although selenate was removed to more than 98.6% from the liquid phase, a less efficient removal of dissolved selenium was observed due to the presence of dissolved alkylated selenium species (dimethylselenide and dimethyldiselenide) and colloidal selenium particles in the effluent. The alkylated and the colloidal fractions contributed up to 15 and 31%, respectively, to the dissolved selenium concentration. The size fractions of the colloidal dispersion were: 4 to 0.45 mum: up to 21%, 0.45 to 0.2 mum: up to 11%, and particles smaller than 0.2 mum: up to 8%. Particles of 4 to 0.45 mum were formed in the external settler, but did not settle. SEM-EDX analysis showed that microorganisms form these selenium containing colloidal particles extracellularly on their surface. Lowering the temperature by 10 degrees C for 6 h resulted in drastically reduced selenate removal efficiencies (after a delay of 1.5 d), accompanied by the temporary formation of an unknown, soluble, organic selenium species. This study shows that a careful process control is a prerequisite for selenium treatment in UASB bioreactors, as disturbances in the operational conditions induce elevated selenium effluent concentrations by alkylation and colloid formation.

Increased plasma selenium is associated with better outcomes in children with systemic inflammation.

PubMed

Leite, Heitor Pons; Nogueira, Paulo Cesar Koch; Iglesias, Simone Brasil de Oliveira; de Oliveira, Susyane Vieira; Sarni, Roseli Oselka Saccardo

2015-03-01

The aim of this study was to assess the effects of changes in plasma selenium on the outcome of critically ill children. Plasma selenium was prospectively measured in 99 children with acute systemic inflammation. The exposure variables were selenium level on admission and on day 5 of stay in the intensive care unit (ICU) and the difference in selenium concentrations between day 5 post-admission and the ICU admission (delta selenium). Selenium was given only as part of enteral diets. Age, malnutrition, red cell glutathione peroxidase-1 activity, serum C-reactive protein, Pediatric Index of Mortality 2, and Pediatric Logistic Organ Dysfunction scores were analyzed as covariates. The outcome variables were ventilator-free days, ICU-free days, and 28-d mortality. Plasma selenium concentrations increased from admission (median 23.4 μg/L, interquartile range 12.0-30.8) to day 5 (median 25.1 μg/L, interquartile range 16.0-39.0; P = 0.018). After adjustment for confounding factors, a delta selenium increase of 10 μg/L was associated with reductions in ventilator days (1.3 d; 95% confidence interval [CI], 0.2-2.3; P = 0.017) and ICU days (1.4 d; 95% CI, 0.5-2.3; P < 0.01). Delta selenium >0 was associated with decreased 28-d mortality on a univariate model (odds ratio, 0.67; 95% CI, 0.46-0.97; P = 0.036). The mean daily selenium intake (6.82 μg; range 0-48.66 μg) was correlated with the increase in selenium concentrations on day 5. An increase in plasma selenium is independently associated with shorter times of ventilation and ICU stay in children with systemic inflammation. These findings raise the hypothesis that selenium supplementation could be beneficial in children with critical illnesses. Copyright © 2015 Elsevier Inc. All rights reserved.

Dietary Selenium Levels Affect Selenoprotein Expression and Support the Interferon-γ and IL-6 Immune Response Pathways in Mice

PubMed Central

Tsuji, Petra A.; Carlson, Bradley A.; Anderson, Christine B.; Seifried, Harold E.; Hatfield, Dolph L.; Howard, Michael T.

2015-01-01

Selenium is an essential element that is required to support a number of cellular functions and biochemical pathways. The objective of this study was to examine the effects of reduced dietary selenium levels on gene expression to assess changes in expression of non-selenoprotein genes that may contribute to the physiological consequences of selenium deficiency. Mice were fed diets that were either deficient in selenium or supplemented with selenium in the form of sodium selenite for six weeks. Differences in liver mRNA expression and translation were measured using a combination of ribosome profiling, RNA-Seq, microarrays, and qPCR. Expression levels and translation of mRNAs encoding stress-related selenoproteins were shown to be up-regulated by increased selenium status, as were genes involved in inflammation and response to interferon-γ. Changes in serum cytokine levels were measured which confirmed that interferon-γ, as well as IL-6, were increased in selenium adequate mice. Finally, microarray and qPCR analysis of lung tissue demonstrated that the selenium effects on immune function are not limited to liver. These data are consistent with previous reports indicating that adequate selenium levels can support beneficial immune responses, and further identify the IL-6 and interferon-γ pathways as being responsive to dietary selenium intake. PMID:26258789

Selenium and mercury molar ratios in commercial fish from New Jersey and Illinois: variation within species and relevance to risk communication.

PubMed

Burger, Joanna; Gochfeld, Michael

2013-07-01

There is an emerging consensus that people consuming large amounts of fish with selenium:mercury ratios below 1 are at higher risk from mercury toxicity. As the relative amount of selenium increases compared to mercury, risk may be lowered, but it is unclear how much excess selenium is required. It would be useful if the selenium:mercury ratio was relatively consistent within a species, but this has not been the case in our studies of wild-caught fish. Since most people in developed countries and urban areas obtain their fish and other seafood commercially, we examined selenium:mercury molar ratios in commercial fish purchased in stores and fish markets in central New Jersey and Chicago. There was substantial interspecific and intraspecific variation in molar ratios. Across species the selenium:mercury molar ratio decreased with increasing mean mercury levels, but selenium variation also contributed to the ratio. Few samples had selenium:mercury molar ratios below 1, but there was a wide range in ratios, complicating the interpretation for use in risk management and communication. Before ratios can be used in risk management, more information is needed on mercury:selenium interactions and mutual bioavailability, and on the relationship between molar ratios and health outcomes. Further, people who are selenium deficient may be more at risk from mercury toxicity than others. Copyright © 2013 Elsevier Ltd. All rights reserved.

Selenium and mercury molar ratios in commercial fish from New Jersey and Illinois: Variation within species and relevance to risk communication

PubMed Central

Burger, Joanna; Gochfeld, Michael

2015-01-01

There is an emerging consensus that people consuming large amounts of fish with selenium:mercury ratios below 1 may be at higher risk from mercury toxicity. As the relative amount of selenium increases compared to mercury, risk may be lowered, but it is unclear how much excess selenium is required. It would be useful if the selenium:mercury ratio was relatively consistent within a species, but this has not been the case in our studies of wild-caught fish. Since most people in developed countries and urban areas obtain their fish and other seafood commercially, we examined selenium:mercury molar ratios in commercial fish purchased in stores and fish markets in central New Jersey and Chicago. There was substantial interspecific and intraspecific variation in molar ratios. Across species the selenium:mercury molar ratio decreased with increasing mean mercury levels, but selenium variation also contributed to the ratio. Few samples had selenium:mercury molar ratios below 1, but there was a wide range in ratios, complicating the interpretation for use in risk management and communication. Before ratios can be used in risk management, more information is needed on mercury:selenium interactions and mutual bioavailability, and on the relationship between molar ratios and health outcomes. Further, people who are selenium deficient may be more at risk from mercury toxicity than others. PMID:23541437

Determination of sub-microgram amounts of selenium in geological materials by atomic-absorption spectrophotometry with electrothermal atomisation after solvent extraction

USGS Publications Warehouse

Sanzolone, R.F.; Chao, T.T.

1981-01-01

An atomic-absorption spectrophotometric method with electrothermal atomisation has been developed for the determination of selenium in geological materials. The sample is decomposed with a mixture of nitric, perchloric and hydrofluoric acids and heated with hydrochloric acid to reduce selenium to selenium (IV). Selenium is then extracted into toluene from a hydrochloric acid - hydrobromic acid medium containing iron. A few microlitres of the toluene extract are injected into a carbon rod atomiser, using a nickel solution as a matrix modifier. The limits of determination are 0.2-200 p.p.m. of selenium in a geological sample. For concentrations between 0.05 and 0.2 p.p.m., back-extraction of the selenium into dilute hydrochloric acid is employed before atomisation. Selenium values for reference samples obtained by replicate analysis are in general agreement with those reported by other workers, with relative standard deviations ranging from 4.1 to 8.8%. Recoveries of selenium spiked at two levels were 98-108%. Major and trace elements commonly encountered in geological materials do not interfere. Arsenic has a suppressing effect on the selenium signals, but only when its concentration is greater than 1000 p.p.m. Nitric acid interferes seriously with the extraction of selenium and must be removed by evaporation in the sample-digestion step.

Selenium Metabolism in Cancer Cells: The Combined Application of XAS and XFM Techniques to the Problem of Selenium Speciation in Biological Systems

PubMed Central

Weekley, Claire M.; Aitken, Jade B.; Finney, Lydia; Vogt, Stefan; Witting, Paul K.; Harris, Hugh H.

2013-01-01

Determining the speciation of selenium in vivo is crucial to understanding the biological activity of this essential element, which is a popular dietary supplement due to its anti-cancer properties. Hyphenated techniques that combine separation and detection methods are traditionally and effectively used in selenium speciation analysis, but require extensive sample preparation that may affect speciation. Synchrotron-based X-ray absorption and fluorescence techniques offer an alternative approach to selenium speciation analysis that requires minimal sample preparation. We present a brief summary of some key HPLC-ICP-MS and ESI-MS/MS studies of the speciation of selenium in cells and rat tissues. We review the results of a top-down approach to selenium speciation in human lung cancer cells that aims to link the speciation and distribution of selenium to its biological activity using a combination of X-ray absorption spectroscopy (XAS) and X-ray fluorescence microscopy (XFM). The results of this approach highlight the distinct fates of selenomethionine, methylselenocysteine and selenite in terms of their speciation and distribution within cells: organic selenium metabolites were widely distributed throughout the cells, whereas inorganic selenium metabolites were compartmentalized and associated with copper. New data from the XFM mapping of electrophoretically-separated cell lysates show the distribution of selenium in the proteins of selenomethionine-treated cells. Future applications of this top-down approach are discussed. PMID:23698165

Overwinter survival of mallards fed selenium

USGS Publications Warehouse

Heinz, G.H.; Fitzgerald, M.A.

1993-01-01

Adult male mallards (Anas platyrhynchos) were fed diets supplemented with 0, 10, 20, 40, or 80 g/g selenium in the form of selenomethionine. Mortality in each of these treatments was 0, 10, 25, 95, and 100%, respectively, during a 16-week exposure that started in November. After one week of treatment, body weights were significantly depressed by the 20, 40, and 80-ug/g selenium treatments, but not by 10 :g/g selenium. Four weeks after being returned to an untreated diet, the body weight of birds fed 20 ug/g selenium had increased to the point of being statistically inseparable from the weight of controls. Signs of selenium poisoning in the dead included severe emaciation, mottling of the liver, empty gizzard, and the presence of a yellowish fluid around some organs. Concentrations of selenium in blood were related to dietary treatments, but mortality was not clearly related to a threshold concentration of selenium in blood.

Potential reproduction and response of selenium and zinc mineral supplementation on quality of goat samosir semen

NASA Astrophysics Data System (ADS)

Siswoyo, P.; Tafsin, M.; Handarini, R.

2018-02-01

The present study was conducted to investigate the effect of suppllementattion of selenium and zinc on semen quality and growth of samosir goat. The experimental design used latin square design (4x4). The treatment supplementation mineral on multi nutrient block (MNB) composed of without sipplementation (p0), +10ppm selenium (p1), +10ppm zinc (p2), +10ppm selenium and +10ppm zinc (p3). The result showed that supplementation mineral selenium and zinc increased significantly (p<0.05) average daily growth, feed consumtion, and lower feed convertion ratio. Semen quality of goat were supplemented by selenium and zinc influenced motility, viability, volume concentration, and responding hypo osmotic swelling (HOS). Combination supplementation selenium and zinc significanly had higher semen quality than ither treatment. It is concluded that supplementation selenium and zinc improve growth and semen quality of samosir goat.

Telomerase as an Androgen Receptor-Regulated Target in Selenium Chemoprevention of Prostate Cancer

DTIC Science & Technology

2010-05-01

TITLE: Telomerase as an Androgen Receptor-Regulated Target in Selenium Chemoprevention of Prostate Cancer PRINCIPAL INVESTIGATOR...May 2009 - 30 Apr 2010 4. TITLE AND SUBTITLE Telomerase as an Androgen Receptor-Regulated Target in Selenium Chemoprevention of Prostate Cancer...telomerase as a potential target of AR signaling suppression by selenium . We found that combination of selenium and bicalutamide produced a robust down

Supplementation with Selenium and Coenzyme Q10 Reduces Cardiovascular Mortality in Elderly with Low Selenium Status. A Secondary Analysis of a Randomised Clinical Trial

PubMed Central

Alexander, Jan; Aaseth, Jan

2016-01-01

Background Selenium is needed by all living cells in order to ensure the optimal function of several enzyme systems. However, the selenium content in the soil in Europe is generally low. Previous reports indicate that a dietary supplement of selenium could reduce cardiovascular disease but mainly in populations in low selenium areas. The objective of this secondary analysis of a previous randomised double-blind placebo-controlled trial from our group was to determine whether the effects on cardiovascular mortality of supplementation with a fixed dose of selenium and coenzyme Q10 combined during a four-year intervention were dependent on the basal level of selenium. Methods In 668 healthy elderly individuals from a municipality in Sweden, serum selenium concentration was measured. Of these, 219 individuals received daily supplementation with selenium (200 μg Se as selenized yeast) and coenzyme Q10 (200 mg) combined for four years. The remaining participants (n = 449) received either placebo (n = 222) or no treatment (n = 227). All cardiovascular mortality was registered. No participant was lost during a median follow-up of 5.2 years. Based on death certificates and autopsy results, all mortality was registered. Findings The mean serum selenium concentration among participants at baseline was low, 67.1 μg/L. Based on the distribution of selenium concentration at baseline, the supplemented group was divided into three groups; <65 μg/L, 65–85 μg/L, and >85 μg/L (45 and 90 percentiles) and the remaining participants were distributed accordingly. Among the non-treated participants, lower cardiovascular mortality was found in the high selenium group as compared with the low selenium group (13.0% vs. 24.1%; P = 0.04). In the group with the lowest selenium basal concentration, those receiving placebo or no supplementation had a mortality of 24.1%, while mortality was 12.1% in the group receiving the active substance, which was an absolute risk reduction of 12%. In the middle selenium concentration group a mortality of 14.0% in the non-treated group, and 6.0% in the actively treated group could be demonstrated; thus, there was an absolute risk reduction of 8.0%. In the group with a serum concentration of >85 μg/L, a cardiovascular mortality of 17.5% in the non-treated group, and 13.0% in the actively treated group was observed. No significant risk reduction by supplementation could thus be found in this group. Conclusions In this evaluation of healthy elderly Swedish municipality members, two important results could be reported. Firstly, a low mean serum selenium concentration, 67 μg/L, was found among the participants, and the cardiovascular mortality was higher in the subgroup with the lower selenium concentrations <65 μg/L in comparison with those having a selenium concentration >85 μg/L. Secondly, supplementation was cardio-protective in those with a low selenium concentration, ≤85 at inclusion. In those with serum selenium>85 μg/L and no apparent deficiency, there was no effect of supplementation. This is a small study, but it presents interesting data, and more research on the impact of lower selenium intake than recommended is therefore warranted. Trial Registration Clinicaltrials.gov NCT01443780 PMID:27367855

Selenium concentrations in the razorback sucker (Xyrauchen texanus): Substitution of non-lethal muscle plugs for muscle tissue in contaminant assessment

USGS Publications Warehouse

Waddell, B.; May, T.

1995-01-01

A single muscle plug was collected from each of 25 live razorback suckers inhabiting the Colorado River basin and analyzed for selenium by instrumental neutron activation. Eight fish from Ashley Creek and three from Razorback Bar exhibited selenium concentrations exceeding 8 μg/g, a level associated with reproductive failure in fish. Concentrations of selenium in eggs and milt were significantly correlated with selenium concentrations in muscle plugs and together indicate a possible explanation for the decline of this species in the Colorado River basin. Muscle plugs (<50mg) and muscle tissue (20 g) were collected from dorsal, anterior, and posterior areas of common carp, flannelmouth sucker, and an archived razorback sucker and analyzed for selenium. Concentrations of selenium in muscle plugs were significantly correlated with selenium concentrations in muscle tissue from the same location and fish (r=0.97). Coefficients of variation for selenium concentrations in each fish were <6.5% for muscle tissue, but ranged from 1.5 to 32.4% for muscle plugs. Increased variation in muscle plugs was attributed to lower selenium concentrations found in the anterior muscle plugs of flannelmouth suckers. Mean selenium concentrations in muscle plugs and tissue from dorsal and posterior areas and muscle tissue from the anterior area were not significantly different. The non-lethal collection of a muscle plug from dorsal and posterior areas of the razorback sucker and other fish species may provide an accurate assessment of selenium concentrations that exist in adjacent muscle tissue.

Assessment of selenium nutritional status of school-age children from rural areas of China in 2002 and 2012.

PubMed

Liu, X; Piao, J; Li, M; Zhang, Y; Yun, C; Yang, C; Yang, X

2016-03-01

To assess the selenium nutritional status of 3458 school-age children recruited from rural areas using the China Nutrition and Health Survey 2002 and 2012 (CNHS 2002 and CNHS 2012). The serum selenium concentration was determined by high-resolution inductively coupled plasma mass spectrometry. The prevalence of dietary selenium intake insufficiency was calculated according to the formula suggested by and the estimated average requirements of the new Chinese Dietary Reference Intakes. The percentage of low selenium was based on the cutoff values with a serum selenium concentration below the threshold limit of clinical importance in coronary and cardiovascular diseases (<45 μg/l) and in abnormal physiological functions (<60 μg/l). The overall median serum selenium concentration was 64.3 μg/l in the CNHS 2002 and 74.2 μg/l in the CNHS 2012. The median calculated dietary selenium intake was 26.7 μg/day in the CNHS 2002 and 33.2 μg/day in the CNHS 2012 together with a 61.1% and 52.8% dietary selenium intake insufficiency in the CNHS 2002 and in the CNHS 2012. In addition, the percentages of low selenium (<45 μg/l and <60 μg/l) were 25.1 and 43.8% in the CNHS 2002 but 9.4 and 25.6% in the CHNS 2012. The selenium nutritional status of school-age children was significantly improved in the CNHS 2012 versus the CNHS 2002. However, the health risk for selenium malnutrition in school-age children remains a potential problem affecting children's health.

Selenium deficiency induced damages and altered expressions of metalloproteinases and their inhibitors (MMP1/3, TIMP1/3) in the kidneys of growing rats.

PubMed

Han, Jing; Liang, Hua; Yi, Jianhua; Tan, Wuhong; He, Shulan; Wu, Xiaofang; Shi, Xiaowei; Ma, Jing; Guo, Xiong

2016-03-01

Selenium is an essential trace element for the maintenance of structures and functions of kidney. To evaluate the effects of low selenium on the kidneys of growing rats, newborn rats were fed with selenium deficient and normal diets respectively for 109 days. As a result, rats fed with low selenium diets resulted in a decline in the body weight and the concentration of selenium in the kidney, especially the male rats from the low selenium groups. Moreover, the ultrastructure of glomerulus and tubules were damaged in low selenium group: the glomeruli were observed with hyperplasia of mesangial cells, fusion of podocyte foot processes and thickening of basement membrane; and the tubules were observed with vacuolar degenerated epithelial cells, increased edema fluid or protein solution between cells, microvilli edema, increased cell gaps and decreased cell links. Furthermore, the pathological changes in selenium deficient group included the increase of fibers around renal hilum aorta and in the renal collecting duct, and shed of cells in the proximal convoluted tubules. In addition, up-regulated expressions of matrix metalloproteinases (MMP1/3) and down-regulated expressions of their inhibitors (TIMP1/3) at the mRNA and protein levels were also appeared to be relevant to low selenium. The results suggested that low selenium in diet may cause low selenium concentration in the kidney of growing rat and lead to damages of the ultrastructure and extracellular matrix (ECM) of kidney. Copyright © 2015 Elsevier GmbH. All rights reserved.

Nano-selenium and its nanomedicine applications: a critical review.

PubMed

Hosnedlova, Bozena; Kepinska, Marta; Skalickova, Sylvie; Fernandez, Carlos; Ruttkay-Nedecky, Branislav; Peng, Qiuming; Baron, Mojmir; Melcova, Magdalena; Opatrilova, Radka; Zidkova, Jarmila; Bjørklund, Geir; Sochor, Jiri; Kizek, Rene

2018-01-01

Traditional supplements of selenium generally have a low degree of absorption and increased toxicity. Therefore, it is imperative to develop innovative systems as transporters of selenium compounds, which would raise the bioavailability of this element and allow its controlled release in the organism. Nanoscale selenium has attracted a great interest as a food additive especially in individuals with selenium deficiency, but also as a therapeutic agent without significant side effects in medicine. This review is focused on the incorporation of nanotechnological applications, in particular exploring the possibilities of a more effective way of administration, especially in selenium-deficient organisms. In addition, this review summarizes the survey of knowledge on selenium nanoparticles, their biological effects in the organism, advantages, absorption mechanisms, and nanotechnological applications for peroral administration.

Plasma Selenium Concentrations Are Sufficient and Associated with Protease Inhibitor Use in Treated HIV-Infected Adults123

PubMed Central

Hileman, Corrilynn O; Dirajlal-Fargo, Sahera; Lam, Suet Kam; Kumar, Jessica; Lacher, Craig; Combs, Gerald F; McComsey, Grace A

2015-01-01

Background: Selenium is an essential constituent of selenoproteins, which play a substantial role in antioxidant defense and inflammatory cascades. Selenium deficiency is associated with disease states characterized by inflammation, including cardiovascular disease (CVD). Although HIV infection has been associated with low selenium, the role of selenium status in HIV-related CVD is unclear. Objectives: We sought to assess associations between plasma selenium and markers of inflammation, immune activation, and subclinical vascular disease in HIV-infected adults on contemporary antiretroviral therapy (ART) and to determine if statin therapy modifies selenium status. Methods: In the Stopping Atherosclerosis and Treating Unhealthy bone with RosuvastatiN trial, HIV-infected adults on stable ART were randomly assigned 1:1 to rosuvastatin or placebo. Plasma selenium concentrations were determined at entry, week 24, and week 48. Spearman correlation and linear regression analyses were used to assess relations between baseline selenium, HIV-related factors and markers of inflammation, immune activation, and subclinical vascular disease. Changes in selenium over 24 and 48 wk were compared between groups. Results: One hundred forty-seven HIV-infected adults were included. All participants were on ART. Median current CD4+ count was 613, and 76% had HIV-1 RNA ≤48 copies/mL (range: <20–600). Median plasma selenium concentration was 122 μg/L (range: 62–200). At baseline, higher selenium was associated with protease inhibitor (PI) use, lower body mass index, and a higher proportion of activated CD8+ T cells (CD8+CD38+human leukocyte antigen-DR+), but not markers of inflammation or subclinical vascular disease. Over 48 wk, selenium concentrations increased in the statin group (P < 0.01 within group), but the change did not differ between groups (+13.1 vs. +5.3 μg/L; P = 0.14 between groups). Conclusions: Plasma selenium concentrations were within the normal range for the background population and were not associated with subclinical vascular disease in HIV-infected adults on contemporary ART. The association between current PI use and higher selenium may have implications for ART allocation, especially in resource-limited countries. Also, it appears that statin therapy may increase selenium concentrations; however, larger studies are necessary to confirm this finding. This trial was registered at clinicaltrials.gov as NCT01218802. PMID:26269240

Forecasting Selenium Discharges to the San Francisco Bay-Delta Estuary: Ecological Effects of A Proposed San Luis Drain Extension

USGS Publications Warehouse

Presser, Theresa S.; Luoma, Samuel N.

2006-01-01

Selenium discharges to the San Francisco Bay-Delta Estuary (Bay-Delta) could change significantly if federal and state agencies (1) approve an extension of the San Luis Drain to convey agricultural drainage from the western San Joaquin Valley to the North Bay (Suisun Bay, Carquinez Strait, and San Pablo Bay); (2) allow changes in flow patterns of the lower San Joaquin River and Bay-Delta while using an existing portion of the San Luis Drain to convey agricultural drainage to a tributary of the San Joaquin River; or (3) revise selenium criteria for the protection of aquatic life or issue criteria for the protection of wildlife. Understanding the biotransfer of selenium is essential to evaluating effects of selenium on Bay-Delta ecosystems. Confusion about selenium threats to fish and wildlife stem from (1) monitoring programs that do not address specific protocols necessary for an element that bioaccumulates; and (2) failure to consider the full complexity of the processes that result in selenium toxicity. Past studies show that predators are more at risk from selenium contamination than their prey, making it difficult to use traditional methods to predict risk from environmental concentrations alone. This report presents an approach to conceptualize and model the fate and effects of selenium under various load scenarios from the San Joaquin Valley. For each potential load, progressive forecasts show resulting (1) water-column concentration; (2) speciation; (3) transformation to particulate form; (4) particulate concentration; (5) bioaccumulation by invertebrates; (6) trophic transfer to predators; and (7) effects on those predators. Enough is known to establish a first-order understanding of relevant conditions, biological response, and ecological risks should selenium be discharged directly into the North Bay through a conveyance such as a proposed extension of the San Luis Drain. The approach presented here, the Bay-Delta selenium model, determines the mass, fate, and effects of selenium released to the Bay-Delta through use of (1) historical land-use, drainage, alluvial-fill, and runoff databases; (2) existing knowledge concerning biogeochemical reactions and physiological parameters of selenium (e.g., speciation, partitioning between dissolved and particulate forms, and bivalve assimilation efficiency); and (3) site-specific data mainly from 1986 to 1996 for clams and bottom-feeding fish and birds. Selenium load scenarios consider effluents from North Bay oil refineries and discharges of agricultural drainage from the San Joaquin Valley to enable calculation of (a) a composite freshwater endmember selenium concentration at the head of the estuary; and (b) a selenium concentration at a selected seawater location (Carquinez Strait) as a foundation for modeling. Analysis of selenium effects also takes into account the mode of conveyance for agricultural drainage (i.e., the San Luis Drain or San Joaquin River); and flows of the Sacramento River and San Joaquin River on a seasonal or monthly basis. Load scenarios for San Joaquin Valley mirror predictions made since 1955 of a worsening salt (and by inference, selenium) build-up exacerbated by an arid climate and massive irrigation. The reservoir of selenium in the San Joaquin Valley is sufficient to provide loading at an annual rate of approximately 42,500 pounds of selenium to a Bay-Delta disposal point for 63 to 304 years at the lower range of projections presented here, even if influx of selenium from the California Coast Ranges could be curtailed. Disposal of wastewaters on an annual basis outside of the San Joaquin Valley may slow the degradation of valley resources, but drainage alone cannot alleviate the salt and selenium build-up in the San Joaquin Valley, at least within a century. Load scenarios also show the different proportions of selenium loading to the Bay-Delta. Oil refinery loads from 1986 to 1992 ranged from 8.5 to 20 pounds of selenium per day;

Selenium

USGS Publications Warehouse

Franson, J.C.

1999-01-01

Selenium is a naturally occurring element that is present in some soils. Unlike mercury and lead, which also are natural environmental components, selenium is an essential nutrient in living systems. The amount of dietary selenium required by animals depends upon many factors, including the availability of certain other metals such as zinc and copper, as well as vitamin E and other nutrients. Muscle damage results if dietary selenium is deficient, but dietary excess can be toxic.

Selenium deficiency in cattle associated with Heinz bodies and anemia.

PubMed

Morris, J G; Cripe, W S; Chapman, H L; Walker, D F; Armstrong, J B; Alexander, J D; Miranda, R; Sanchez, A; Sanchez, B; Blair-West, J R

1984-02-03

Cattle grazing St. Augustine grass growing on peaty muck soils in the Florida Everglades developed anemia associated with the presence of Heinz bodies and suboptimal concentrations of selenium in blood. Selenium supplementation corrected the anemia, prevented Heinz body formation, increased the body weight of cows and calves, and elevated blood selenium. This may be the first recorded example of widespread anemia in a population due to selenium deficiency.

Avoidance of selenium-treated food by mallards

USGS Publications Warehouse

Heinz, G.H.; Sanderson, C.J.

1990-01-01

Adult, male mallards (Anas platyrhynchos) were given a choice between a control diet and a diet containing 5, 10 or 20 ppm selenium as selenomethionine dissolved in water and mixed into the diet. At 10 and 20 ppm, selenium-treated diets were avoided. Avoidance appeared to be caused by a conditioned response, probably to illness caused by the selenium and not to an aversion to the taste of the selenium.

Selenium and selenocysteine: roles in cancer, health and development

PubMed Central

Hatfield, Dolph L.; Tsuji, Petra A.; Carlson, Bradley A.; Gladyshev, Vadim N.

2014-01-01

The many biological and biomedical effects of selenium are relatively unknown outside the selenium field. This fascinating element, initially described as a toxin, was subsequently shown to be essential for health and development. By the mid 1990s, selenium emerged as one of the most promising cancer chemopreventive agents, but subsequent human clinical trials yielded contradictory results. However, basic research on selenium continued to move at a rapid pace elucidating its many roles in health, development, and cancer prevention and promotion. Dietary selenium acts principally through selenoproteins, most of which are oxidoreductases involved in diverse cellular functions. PMID:24485058

Hazard assessment of selenium to endangered razorback suckers (Xyrauchen texanus)

USGS Publications Warehouse

Hamilton, S.J.; Holley, K.M.; Buhl, K.J.

2002-01-01

A hazard assessment was conducted based on information derived from two reproduction studies conducted with endangered razorback suckers (Xyrauchen texanus) at three sites near Grand Junction, CO, USA. Selenium contamination of the upper and lower Colorado River basin has been documented in water, sediment, and biota in studies by US Department of the Interior agencies and academia. Concern has been raised that this selenium contamination may be adversely affecting endangered fish in the upper Colorado River basin. The reproduction studies with razorback suckers revealed that adults readily accumulated selenium in various tissues including eggs, and that 4.6 μg/g of selenium in food organisms caused increased mortality of larvae. The selenium hazard assessment protocol resulted in a moderate hazard at the Horsethief site and high hazards at the Adobe Creek and North Pond sites. The selenium hazard assessment was considered conservative because an on-site toxicity test with razorback sucker larvae using 4.6 μg/g selenium in zooplankton caused nearly complete mortality, in spite of the moderate hazard at Horsethief. Using the margin of uncertainty ratio also suggested a high hazard for effects on razorback suckers from selenium exposure. Both assessment approaches suggested that selenium in the upper Colorado River basin adversely affects the reproductive success of razorback suckers.

Effects of selenium on mallard duck reproduction and immune function

DOE Office of Scientific and Technical Information (OSTI.GOV)

Whiteley, P.L.; Yuill, T.M.; Fairbrother, A.

Selenium from irrigation drain water and coal-fired power stations is a significant environmental contaminant in some regions of the USA. The objectives were to examine whether selenium-exposed waterfowl had altered immune function, disease resistance, or reproduction. Pairs of adult mallards were exposed for 95-99 days on streams with sodium selenite-treated water at 10 and 30 ppb, or on untreated streams. Selenium biomagnified through the food chain to the ducks. Disease resistance was decreased in ducklings hatched on the streams and challenged with duck hepatitis virus 1 (DHV1) when 15-days old. Liver selenium concentrations for these ducklings on the 10 andmore » 30 ppb streams was 3.6 and 7.6 ppm dry weight, respectively. Mortality of ducklings purchased when 7-days old, exposed to selenium for 14 days, and challenged when 22-days old was not affected. However, their selenium exposure was lower (liver selenium 4.1 ppm dry weight for the 30 ppb stream). Five parameters of immune function were measured in adult ducks. Phagocytosis of killed Pasteurella multocida by blood heterophils and monocytes, and blood monocyte concentrations were higher in adult males following 84 days exposure to 30 ppb selenium. Their liver selenium concentrations were 11.1 ppm dry weight after 95-99 days exposure.« less

Hazard assessment of selenium to endangered razorback suckers (Xyrauchen texanus).

PubMed

Hamilton, Steven J; Holley, Kathleen M; Buhl, Kevin J

2002-05-27

A hazard assessment was conducted based on information derived from two reproduction studies conducted with endangered razorback suckers (Xyrauchen texanus) at three sites near Grand Junction, CO, USA. Selenium contamination of the upper and lower Colorado River basin has been documented in water, sediment, and biota in studies by US Department of the Interior agencies and academia. Concern has been raised that this selenium contamination may be adversely affecting endangered fish in the upper Colorado River basin. The reproduction studies with razorback suckers revealed that adults readily accumulated selenium in various tissues including eggs, and that 4.6 microg/g of selenium in food organisms caused increased mortality of larvae. The selenium hazard assessment protocol resulted in a moderate hazard at the Horsethief site and high hazards at the Adobe Creek and North Pond sites. The selenium hazard assessment was considered conservative because an on-site toxicity test with razorback sucker larvae using 4.6 microg/g selenium in zooplankton caused nearly complete mortality, in spite of the moderate hazard at Horsethief. Using the margin of uncertainty ratio also suggested a high hazard for effects on razorback suckers from selenium exposure. Both assessment approaches suggested that selenium in the upper Colorado River basin adversely affects the reproductive success of razorback suckers.

Copper/zinc and copper/selenium ratios, and oxidative stress as biochemical markers in recurrent aphthous stomatitis.

PubMed

Ozturk, Perihan; Belge Kurutas, Ergul; Ataseven, Arzu

2013-10-01

Recurrent aphthous stomatitis (RAS) is a common oral mucosal disorder characterized by recurrent, painful oral aphthae, and oxidative stress presumably contributes to its pathogenesis. The aim of this study is to scrutinize the relationship between oxidative stress and serum trace elements (copper, Cu; zinc, Zn; selenium, Se), and to evaluate the ratios of Cu/Zn and Cu/Se in this disorder. Patients with RAS (n = 33) and age- and sex-matched healthy control subjects (n = 30) were enrolled in this study. Malondialdehyde (MDA) concentrations in plasma and the activities of superoxide dismutase (SOD1; CuZnSOD), glutathione peroxidase (GPx) and catalase (CAT) in erythrocyte were determined as spectrophotometric. Also, the levels of Se, Zn and Cu in serum were determined on flame and furnace atomic absorption spectrophotometer using Zeeman background correction. Oxidative stress was confirmed by the significant elevation in plasma MDA, and by the significant decrease in CAT, SOD1, and GPx (p < 0.05). When compared to controls, Zn and Se levels were significantly lower in patients, whereas Cu levels was higher in RAS patients than those in controls (p < 0.05). In addition, the correlation results of this study were firstly shown that there were significant and positive correlations between Se-CAT, Se-GPx, and Cu-MDA parameters, but negative correlations between Se-Cu, Se-MDA, Cu-CAT, Cu-SOD1 and Cu-GPx parameters in RAS patients. Furthermore, the ratios of Cu/Zn and Cu/Se were significantly higher in the patients than the control subjects (p < 0.05). Our results indicated that lipid peroxidation associated with the imbalance of the trace elements seems to play a crucial role in the pathogenesis of RAS. Furthermore, the serum Cu/Zn and Cu/Se ratios may be used as biochemical markers in these patients. Crown Copyright © 2013. Published by Elsevier GmbH. All rights reserved.

Selenium-Rich Ricegrass Juice Improves Antioxidant Properties and Nitric Oxide Inhibition in Macrophage Cells

PubMed Central

Puttarak, Panupong; Brantner, Adelheid; Siripongvutikorn, Sunisa

2018-01-01

Ricegrass juice (Oryza sativa L.) was introduced as a functional food as the consumption of sprouts or seedlings has been claimed to provide high nutritive value. Selenium (Se) is a trace mineral that plays a key role in the human antioxidation scheme. Supplementation of Se into plants is one strategy to enhance plant bioactivities, and the consumption of Se plant foods may confer superior health benefits. In this study, ricegrass juice extract was analyzed for its major phenolic components. The effect of ricegrass juice extracts bio-fortified with 0, 10 and 40 mg Se/L named as RG0, RG10, and RG40, respectively, were investigated for a percentage of cell viability, changes of endogenous antioxidant enzymes, lipid peroxidation, and nitric oxide inhibition in RAW264.7 macrophage cells. Flavone glycosides, namely chrysoeriol arabinosyl arabinoside derivatives, were found to be the foremost bioactive components in ricegrass juice extract indicated by UHPLC-MS. The results of cell culture assessment revealed that RG40 showed an ability to promote macrophage cell proliferation at low concentration. Ricegrass juice extract in all treatments possessed the ability to reduce malondialdehyde content, which may be regarded as the bioactivity of phenolic compounds. Moreover, Se also played a role in this effect since RG40 showed the greatest ability via increasing the level of GPx enzyme. It was also discovered that phenolic compounds in the extracts played a role in inhibiting nitric oxide in LPS-induced RAW264.7 cells. Furthermore, RG40 expressed significantly higher NO inhibition properties at IC50 118.76 µg/mL compared to RG0 and RG10, at 147.02 and 147.73 µg/mL, respectively. Se bio-fortified ricegrass juice could be considered as a new potent functional food that can lower the risk of oxidative stress and chronic inflammation diseases. PMID:29652839

Sublethal effects in Avocet and Stilt hatchlings from selenium-contaminated sites

USGS Publications Warehouse

Hoffman, D.J.; Marn, C.M.; Marois, Katherine C.; Sproul, E.; Dunne, M.; Skorupa, J.P.

2002-01-01

Excess selenium (Se) in the aquatic food chain is embryotoxic and teratogenic to avocets, stilts, and other waterbirds. American avocet (Recurvirostra americana) and black-necked stilt (Himantopus mexicanus) eggs were collected from three sites in the Tulare Lake Basin of California, USA, and hatched in the laboratory. These sites included the Tulare Lake Drainage District?north (TLDD-N, water 2.5 ppb Se), TLDD?south (TLDD-S, water 8.6 ppb Se), and Westfarmers (WF, water 190 ppb Se). Highest egg Se concentrations occurred at WF (geometric mean 31.4 ppm dry wt for avocets and 20.5 ppm dry wt for stilts). Mean egg Se concentrations were 6.7 ppm for avocets and 8.4 ppm for stilts at TLDD-S, and 3.3 ppm for avocets and 2.3 ppm for stilts at TLDD-N. Hatching success and incidence of malformations did not differ among sites, but yolk sac?free hatching weights and bone lengths were less for avocets at the WF site, whereas liver weights and liver to body weight ratios were greater at that site. With increasing Se concentration, oxidative stress was most apparent in avocet hatchlings from WF: hepatic glutathione (GSH) peroxidase activity increased, glucose-6-phosphate dehydrogenase activity decreased, and oxidized glutathione (GSSG) concentration as well as the ratio of GSSG to reduced GSH concentration increased. In stilts, hepatic GSH concentration was lower in WF hatchlings. In conclusion, our findings of Se-impaired embryo growth and hepatotoxicity in avocet hatchlings suggest that oxidative stress observed in hatchlings may be related to these biological effects and may serve as a potential bioindicator of subsequent impaired functions.

Dietary selenium increases the antioxidant levels and ATPase activity in the arteries and veins of poultry.

PubMed

Cao, Changyu; Zhao, Xia; Fan, Ruifeng; Zhao, Jinxin; Luan, Yilin; Zhang, Ziwei; Xu, Shiwen

2016-07-01

Selenium (Se) deficiency is associated with the pathogenesis of vascular diseases. It has been shown that oxidative levels and ATPase activity were involved in Se deficiency diseases in humans and mammals; however, the mechanism by how Se influences the oxidative levels and ATPase activity in the poultry vasculature is unclear. We assessed the effects of dietary Se deficiency on the oxidative stress parameters (superoxide dismutase, catalase, and hydroxyl radical) and ATPase (Na(+)K(+)-ATPase, Ca(++)-ATPase, Mg(++)-ATPase, and Ca(++)Mg(++)-ATPase) activity in broiler poultry. A total of 40 broilers (1-day old) were randomly divided into a Se-deficient group (L group, fed a Se-deficient diet containing 0.08 mg/kg Se) and a control group (C group, fed a diet containing sodium selenite at 0.20 mg/kg Se). Then, arteries and veins were collected following euthanasia when typical symptoms of Se deficiency appeared. Antioxidant indexes and ATPase activity were evaluated using standard assays in arteries and veins. The results indicated that superoxide dismutase activity in the artery according to dietary Se deficiency was significantly lower (p < 0.05) compared with the C group. The catalase activity in the veins and hydroxyl radical inhibition in the arteries and veins by dietary Se deficiency were significantly higher (p < 0.05) compared with the C group. The Se-deficient group showed a significantly lower (p < 0.05) tendency in Na(+)K(+)-ATPase activity, Ca(++)-ATPase activity, and Ca(++)Mg(++)-ATPase activity. There were strong correlations between antioxidant indexes and Ca(++)-ATPase activity. Thus, these results indicate that antioxidant indexes and ATPases may have special roles in broiler artery and vein injuries under Se deficiency.

Effect of Selenium on Lipid and Amino Acid Metabolism in Yeast Cells.

PubMed

Kieliszek, Marek; Błażejak, Stanisław; Bzducha-Wróbel, Anna; Kot, Anna M

2018-04-19

This article discusses the effect of selenium in aqueous solutions on aspects of lipid and amino acid metabolism in the cell biomass of Saccharomyces cerevisiae MYA-2200 and Candida utilis ATCC 9950 yeasts. The yeast biomass was obtained by using waste products (potato wastewater and glycerol). Selenium, at a dose of 20 mg/L of aqueous solution, affected the differentiation of cellular morphology. Yeast enriched with selenium was characterized by a large functional diversity in terms of protein and amino acid content. The protein content in the biomass of S. cerevisiae enriched with selenium (42.6%) decreased slightly as compared to that in the control sample without additional selenium supplementation (48.4%). Moreover, yeasts of both strains enriched with selenium contained a large amount of glutamic acid, aspartic acid, lysine, and leucine. Analysis of fatty acid profiles in S. cerevisiae yeast supplemented with selenium showed an increase in the unsaturated fatty acid content (e.g., C18:1). The presence of margaric acid (C17:0) and hexadecanoic acid (C17:1) was found in the C. utilis biomass enriched with selenium, in contrast to that of S. cerevisiae. These results indicate that selenium may induce lipid peroxidation, which consequently affects the loss of integrity of the cytoplasmic membrane. Yeast enriched with selenium with optimal amino acid and lipid composition can be used to prepare a novel formula of dietary supplements, which can be applied directly to various diets for both humans and animals.

Selenium and Preeclampsia: a Systematic Review and Meta-analysis.

PubMed

Xu, Min; Guo, Dan; Gu, Hao; Zhang, Li; Lv, Shuyan

2016-06-01

Conflicting results exist between selenium concentration and preeclampsia. The role of selenium in the development of preeclampsia is unclear. We conducted a meta-analysis to compare the blood selenium level in patients with preeclampsia and healthy pregnant women, and to determine the effectiveness of selenium supplementation in preventing preeclampsia. We searched PubMed, ScienceDirect, the Cochrane Library, and relevant references for English language literature up to November 25, 2014. Mean difference from observational studies and relative risk from randomized controlled trials were meta-analyzed by a random-effect model. Thirteen observational studies with 1515 participants and 3 randomized controlled trials with 439 participants were included in the meta-analysis. Using a random-effect model, a statistically significant difference in blood selenium concentration of -6.47 μg/l (95 % confidence interval (CI) -11.24 to -1.7, p = 0.008) was seen after comparing the mean difference of observational studies. In randomized controlled trials, using a random-effect model, the relative risk for preeclampsia was 0.28 (0.09 to 0.84) for selenium supplementation (p = 0.02). Evidence from observational studies indicates an inverse association of blood selenium level and the risk of preeclampsia. Supplementation with selenium significantly reduces the incidence of preeclampsia. However, more prospective clinical trials are required to assess the association between selenium supplementation and preeclampsia and to determine the dose, beginning time, and duration of selenium supplementation.

Nano-selenium and its nanomedicine applications: a critical review

PubMed Central

Hosnedlova, Bozena; Kepinska, Marta; Skalickova, Sylvie; Fernandez, Carlos; Ruttkay-Nedecky, Branislav; Peng, Qiuming; Baron, Mojmir; Melcova, Magdalena; Opatrilova, Radka; Zidkova, Jarmila; Bjørklund, Geir; Sochor, Jiri; Kizek, Rene

2018-01-01

Traditional supplements of selenium generally have a low degree of absorption and increased toxicity. Therefore, it is imperative to develop innovative systems as transporters of selenium compounds, which would raise the bioavailability of this element and allow its controlled release in the organism. Nanoscale selenium has attracted a great interest as a food additive especially in individuals with selenium deficiency, but also as a therapeutic agent without significant side effects in medicine. This review is focused on the incorporation of nanotechnological applications, in particular exploring the possibilities of a more effective way of administration, especially in selenium-deficient organisms. In addition, this review summarizes the survey of knowledge on selenium nanoparticles, their biological effects in the organism, advantages, absorption mechanisms, and nanotechnological applications for peroral administration. PMID:29692609

Search for relevant indications for selenium supplementation in thyroid diseases.

PubMed

Wojciechowska-Durczynska, Katarzyna; Lewinski, Andrzej

2017-08-01

Selenium plays a significant role in the thyroid function and its deficiency is considered by some authors to be a cause of thyroid disorders. The potential therapeutic influence of selenium supplementation in thyroid disease was investigated in several studies and some results were encouraging, however results were inconsistent and did not allow conclusion to be drawn. For that reason, we have performed a review study on relevance of selenium supplementation in thyroid disease. Till now, there is no strong evidence that selenium supplementation leads to clinical improvement in the course of autoimmune thyroiditis, nodular goitre or thyroid cancer. On the other hand, there is some evidence that selenium is effective in the treatment of orbitopathy; thus, the European Group on Graves' Orbitopathy (EUGOGO) recommends selenium administration in mild active orbitopathy.

Selenium as an essential micronutrient: roles in cell cycle and apoptosis.

PubMed

Zeng, Huawei

2009-03-23

Selenium is an essential trace element for humans and animals, and selenium deficiency is associated with several disease conditions such as immune impairment. In addition, selenium intakes that are greater than the recommended daily allowance (RDA) appear to protect against certain types of cancers. In humans and animals, cell proliferation and death must be regulated to maintain tissue homeostasis, and it has been well documented that numerous human diseases are directly related to the control of cell cycle progression and apoptosis. Thus, the elucidation of the mechanisms by which selenium regulates the cell cycle and apoptosis can lead to a better understanding of the nature of selenium's essentiality and its role in disease prevention. This article reviews the status of knowledge concerning the effect of selenium on cell cycle and apoptosis.

Selenium exposure and depressive symptoms: the Coronary Artery Risk Development in Young Adults Trace Element Study

PubMed Central

Colangelo, Laura A; He, Ka; Whooley, Mary A; Daviglus, Martha L.; Morris, Steven; Liu, Kiang

2014-01-01

Selenium is an essential trace element important to neurotransmission, but toxic at high levels. Some studies suggest beneficial effects on mood. We assessed the association of selenium exposure with presence of depressive symptoms. Selenium exposure was measured in toenail samples collected in 1987 from 3,735 US participants (age 20–32 years) and depressive symptoms assessed in 1990, 1995, 2000, 2005, and 2010 using the Center for Epidemiologic Studies Depression Scale (CES-D). Binary and polytomous logistic regression models were used to assess the relation of log2(selenium) and selenium quintiles with presence of depressive symptoms (CES-D score ≥ 27 or on antidepressant medication). Relative to selenium quintile 1, the adjusted odds ratio (OR) for having depressive symptoms in 1990 for quintile 5 was 1.59 (95% CI: 1.01, 2.51) and a unit increase in log2(selenium), which represents a doubling of the selenium level, was associated with an OR=2.03 (95% CI: 1.12, 3.70). When examining 1, 2 or 3+ exams vs no exams with symptoms, the OR for quintile 5 was 1.73 (1.04, 2.89) for 3+ exams and for one exam and two exams, there were no associations. In a generalized estimating equations longitudinal model, a doubling of the selenium level was associated with a 56% higher odds of having depressive symptoms at an exam. Contrary to previously reported findings related to mood, higher level of selenium exposure was associated with presence of elevated depressive symptoms. More research is needed to elucidate the role of selenium in depressive disorders. PMID:24560993

Effect of Selenium Supplementation on Recurrent Hyperthyroidism Caused by Graves' Disease: A Prospective Pilot Study.

PubMed

Wang, L; Wang, B; Chen, S R; Hou, X; Wang, X F; Zhao, S H; Song, J Q; Wang, Y G

2016-09-01

The effect of selenium supplementation on recurrent hyperthyroidism caused by Graves' disease is unclear. Our study aimed to assess the efficacy of selenium supplementation therapy on recurrent Graves' disease. Forty-one patients with recurrent Graves' disease were enrolled in this study. All patients received the routine treatment using methimazole (MMI), while patients allocated to the selenium group received additional selenium therapy for 6 months. The influence of selenium supplementation on the concentrations of thyroid stimulating hormone (TSH), anti-TSH-receptor antibodies (TRAb), free thyroxine (FT4), and free triiodothyronine (FT3) were assessed. The remission rate was also compared between 2 groups. There was no obvious difference in the demographic data and the levels of serum FT4, FT3, TSH, and TRAb between the 2 groups at baseline. Both FT4 and FT3 decreased more at 2 months in the selenium group than the controls, while the TSH level increased more in patients receiving selenium supplementation (p<0.05). The TRAb level was significantly lower in patients receiving selenium supplementation (2.4 IU/l vs. 5.6 IU/l, p=0.04). The percentages of patients with normal TRAb level at 6 months was also significantly higher in the selenium group (19.0 vs. 0%, p=0.016). Kaplan-Meier survival curve showed patients receiving selenium supplementation had a significantly higher rate of remission than controls (Log-rank test p=0.008). In conclusion, selenium supplementation can enhance the effect of antithyroid drugs in patients with recurrent Graves' disease. Randomized trials with large number of participants are needed to validate the finding above. © Georg Thieme Verlag KG Stuttgart · New York.

Field screening of water, soil, bottom sediment, and biota associated with irrigation drainage in the Dolores Project and the Macos River basin, southwestern Colorado, 1994

USGS Publications Warehouse

Butler, D.L.; Osmundson, B.C.; Krueger, R.P.

1997-01-01

A reconnaissance investigation for the National Irrigation Water Quality Program in 1990 indicated elevated selenium concentrations in some water and biota samples collected in the Dolores Project in southwestern Colorado. High selenium concentrations also were indicated in bird samples collected in the Mancos Project in 1989. In 1994, field screenings were done in parts of the Dolores Project and Mancos River Basin to collect additional selenium data associated with irrigation inthose areas. Selenium is mobilized from soils in newly irrigated areas of the Dolores Project called the Dove Creek area, which includes newly (since 1987) irrigated land north of Cortez and south of Dove Creek.Selenium was detected in 18 of 20stream samples, and the maximum concentration was 12micrograms per liter. The Dove Creek area is unique compared to other study areas of the National Irrigation Water Quality Program becauseselenium concentrations probably are indicative of initial leaching conditions in a newly irrigated area.Selenium concentrations in nine shallow soil samples from the Dove Creek area ranged from 0.13 to 0.20 micrograms per gram. Selenium concentrations in bottom sediment from six ponds were less than the level of concern for fish and wildlife of 4 micrograms per gram. Many biota samples collected in the Dove Creek area had elevated selenium concentrations when compared to various guidelines and effect levels,although selenium concentrations in water, soil, and bottom sediment were relatively low. Selenium concentrations in 12 of 14 aquatic-invertebratesamples from ponds exceeded 3 micrograms per gram dry weight, a dietary guideline for protection of fish and wildlife. The mean seleniumconcentration of 10.3 micrograms per gram dry weight in aquatic bird eggs exceeded the guideline for reduced hatchability of 8 micrograms per gramdry weight. Two ponds in the Dove Creek area had a high selenium hazard rating based on a new protocol for assessing selenium hazard in theenvironment; however, waterfowl were reproducing at the two ponds. Three tributary streams of Mc Elmo Creek that drain irrigated areas of the Montezuma Valley south of the creek were sampled in 1994. Mud Creek probably is the largest source of selenium to Mc Elmo Creek. Most biota samples from Mud Creek had elevated selenium concentrations when compared to guidelines for dietary items and freshwater fish. Selenium concentrations in water samples collected in the Mancos River Basin upstream from Navajo Wash, which includes the Mancos Project, ranged from less than 1 to 10 micrograms per liter. Mud Creek contributed about 74 percent of the selenium load to the upper Mancos River in March 1994.Selenium concentrations were much higher in Navajo Wash; a sample collected in March had 97 micrograms per liter of selenium. Bottom-sediment samples from two ponds in the Mancos Projectexceeded the concentration of concern of 4 micrograms per gram. The highest selenium concentrations in biota samples from streams in the Mancos River Basin were for samples from Navajo Wash. Mostconcentrations in biota in the upper Mancos River Basin were less than guidelines. Mean selenium concentrations in eggs from aquatic birds collected at three ponds in the Mancos Project slightly exceed the guideline associated with reduced hatchability.Five bird livers had a mean selenium concentration of 32.6 micrograms per gram dry weight, whichslightly exceeded the mean concentration of 30 micrograms per gram dry weight that is associated with reproductive impairment. Two of the pondshad a high selenium hazard rating; however, mallard reproduction was observed in 1994 at one of the ponds that had a high selenium-hazard rating.

Interspecific and intraspecific variation in selenium:mercury molar ratios in saltwater fish from the Aleutians: Potential protection on mercury toxicity by selenium

PubMed Central

Burger, Joanna; Gochfeld, Michael; Jeitner, Christian; Donio, Mark; Pittfield, Taryn

2014-01-01

A number of factors affect the consumption risk from mercury in fish, including mercury levels, seasonal patterns of mercury concentrations, human consumption patterns, and sensitive populations (e.g. pregnant women, fetuses, young children, and yet unknown genetic factors). Recently the protective effects of selenium on methylmercury toxicity have been publicized, particularly for saltwater fish. We examine levels of mercury and selenium in several species of fish and seabirds from the Aleutians (Alaska), determine selenium:mercury molar ratios, and examine species-specific and individual variation in the ratios as a means of exploring the use of the ratio in risk assessment and risk management. Variation among species was similar for mercury and selenium. There was significant inter-specific and intraspecific variation in selenium:mercury molar ratios for fish, and for birds. The mean selenium:mercury molar ratios for all fish and bird species were above 1, meaning there was an excess of selenium relative to mercury. It has been suggested that an excess of selenium confers some protective advantage for salt water fish, although the degree of excess necessary is unclear. The selenium:mercury molar ratio was significantly correlated negatively with total length for most fish species, but not for dolly varden. Some individuals of Pacific cod, yellow irish lord, rock greenling, Pacific halibut, dolly varden, and to a lesser extent, flathead sole, had selenium:mercury ratios below 1. No bird muscle had an excess of mercury (ratio below 1), and only glaucous-winged gull and pigeon guillemot had ratios between 1 and 5. There was a great deal of variation in selenium:mercury molar ratios within fish species, and within bird species, making it difficult and impractical to use these ratios in risk assessment or management, for fish advisories, or for consumers, particularly given the difficulty of interpreting the ratios. PMID:22664537

Multicenter, Phase 3 Trial Comparing Selenium Supplementation With Observation in Gynecologic Radiation Oncology

DOE Office of Scientific and Technical Information (OSTI.GOV)

Muecke, Ralph; Schomburg, Lutz; Glatzel, Michael

Purpose: We assessed whether adjuvant supplementation with selenium improves the selenium status and reduces side effects of patients treated by radiotherapy (RT) for cervical and uterine cancer. Methods and Materials: Whole-blood selenium concentrations were measured in patients with cervical cancer (n = 11) and uterine cancer (n = 70) after surgical treatment, during RT, at the end of RT, and 6 weeks after RT. Patients with initial selenium concentrations of less than 84{mu}g/L were randomized before RT either to receive 500 {mu}g of selenium (in the form of sodium selenite [selenase (registered) , biosyn Arzneimittel GmbH, Fellbach, Germany]) by mouthmore » on the days of RT and 300 {mu}g of selenium on the days without RT or to receive no supplement during RT. The primary endpoint of this multicenter Phase 3 study was to assess the efficiency of selenium supplementation during RT; the secondary endpoint was to decrease radiation-induced diarrhea and other RT-dependent side effects. Results: A total of 81 patients were randomized. We enrolled 39 in the selenium group (SG) and 42 in the control group (CG). Selenium levels did not differ between the SG and CG upon study initiation but were significantly higher in the SG at the end of RT. The actuarial incidence of diarrhea of Grade 2 or higher according to Common Toxicity Criteria (version 2) in the SG was 20.5% compared with 44.5% in the CG (p = 0.04). Other blood parameters, Eastern Cooperative Oncology Group performance status, and self-reported quality of life were not different between the groups. Conclusions: Selenium supplementation during RT is effective in improving blood selenium status in selenium-deficient cervical and uterine cancer patients and reduces the number of episodes and severity of RT-induced diarrhea.« less

Selenium-Enriched Foods Are More Effective at Increasing Glutathione Peroxidase (GPx) Activity Compared with Selenomethionine: A Meta-Analysis

PubMed Central

Bermingham, Emma N.; Hesketh, John E.; Sinclair, Bruce R.; Koolaard, John P.; Roy, Nicole C.

2014-01-01

Selenium may play a beneficial role in multi-factorial illnesses with genetic and environmental linkages via epigenetic regulation in part via glutathione peroxidase (GPx) activity. A meta-analysis was undertaken to quantify the effects of dietary selenium supplementation on the activity of overall GPx activity in different tissues and animal species and to compare the effectiveness of different forms of dietary selenium. GPx activity response was affected by both the dose and form of selenium (p < 0.001). There were differences between tissues on the effects of selenium supplementation on GPx activity (p < 0.001); however, there was no evidence in the data of differences between animal species (p = 0.95). The interactions between dose and tissue, animal species and form were significant (p < 0.001). Tissues particularly sensitive to changes in selenium supply include red blood cells, kidney and muscle. The meta-analysis identified that for animal species selenium-enriched foods were more effective than selenomethionine at increasing GPx activity. PMID:25268836

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

PubMed

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 antioxidant pathways linking selenium to mood. This trial was registered with the Australian New Zealand Clinical Trials Registry as ACTRN12613000773730. © 2015 American Society for Nutrition.

Hepatic glutathione metabolism and lipid peroxidation in response to excess dietary selenomethionine and selenite in mallard ducklings

USGS Publications Warehouse

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

1989-01-01

Selenium from selenomethionine accumulated in a dose-dependent manner in the liver, resulting in a decrease in hepatic-reduced glutathione with a corresponding decrease in total hepatic thiols. There was a dose-dependent increase in the oxidized to reduced glutathione ratio, and an increase in lipid peroxidation. These findings indicate that Se in the diet at 10 ppm and higher causes significant sublethal alterations in mallard ducklings, and 20-40 ppm causes significant hepatotoxicity.

Transformations of Heavy Metals and Plant Nutrients in Dredged Sediments as Affected by Oxidation Reduction Potential and pH. Volume 1. Literature Review

DTIC Science & Technology

1977-05-01

895-896 (1974). 191. Fagerstrom, T., and Jernelov, A. "Formation of Methyl Mercury from Pure Mercuric Sulphide in Aerobic Organic Sediment." Water...was available. The toxic and nutrient elements included are lead, cadmium, mercury , arsenic, selenium, copper, zinc, manganese, iron, nitrogen...on the exchange of these materials between sediment and water. The toxic and nutrient elements included are lead, cadmium, mercury , ar- senic

Simple method for determination of selenium in biological materials by flameless atomic-absorption spectrometry using a carbon-tube atomizer.

PubMed

Ishizaki, M

1978-03-01

A method for determination of selenium in biological materials by flameless atomic-absorption spectrometry using a carbon-tube atomizer is described. The sample is burned by an oxygen-flask combustion procedure, the resulting solution is treated with a cation-exchange resin to eliminate interfering cations, the selenium is extracted with dithizone in carbon tetrachloride and the resulting selenium dithizonate is combined with nickel nitrate in the carbon tube to enhance the sensitivity for selenium and avoid volatilization losses. The method measures selenium concentrations as low as 0.01 mug/g with a relative standard deviation of 8%.

Improved selenium recovery from tissue with modified sample decomposition

USGS Publications Warehouse

Brumbaugh, W. G.; Walther, M.J.

1991-01-01

The present paper describes a simple modification of a recently reported decomposition method for determination of selenium in biological tissue by hydride generation atomic absorption. The modified method yielded slightly higher selenium recoveries (3-4%) for selected reference tissues and fish tissue spiked with selenomethionine. Radiotracer experiments indicated that the addition of a small volume of hydrochloric acid to the wet digestate mixture reduced slight losses of selenium as the sample initially went to dryness before ashing. With the modified method, selenium spiked as selenomethionine behaved more like the selenium in reference tissues than did the inorganic spike forms when this digestion modification was used.

An evaluation of selenium concentrations in water, sediment, invertebrates, and fish from the Solomon River Basin

USGS Publications Warehouse

May, T.W.; Fairchild, J.F.; Petty, J.D.; Walther, M.J.; Lucero, J.; Delvaux, M.; Manring, J.; Armbruster, M.

2008-01-01

The Solomon River Basin is located in north-central Kansas in an area underlain by marine geologic shales. Selenium is an indigenous constituent of these shales and is readily leached into the surrounding groundwater. Portions of the Basin are irrigated primarily through the pumping of selenium-contaminated groundwater from wells onto fields in agricultural production. Water, sediment, macroinvertebrates, and fish were collected from various sites in the Basin in 1998 and analyzed for selenium. Selenium concentrations were analyzed spatially and temporally and compared to reported selenium toxic effect thresholds for specific ecosystem components: water, sediments, food-chain organisms, and wholebody fish. A selenium aquatic hazard assessment for the Basin was determined based on protocol established by Lemly. Throughout the Basin, water, macroinvertebrate, and whole fish samples exceeded levels suspected of causing reproductive impairment in fish. Population structures of several fish species implied that successful reproduction was occurring; however, the influence of immigration of fish from low-selenium habitats could not be discounted. Site-specific fish reproduction studies are needed to determine the true impact of selenium on fishery resources in the Basin. ?? Springer Science+Business Media B.V. 2007.

Selenium, selenoprotein genes and Crohn's disease in a case-control population from Auckland, New Zealand.

PubMed

Gentschew, Liljana; Bishop, Karen S; Han, Dug Yeo; Morgan, Angharad R; Fraser, Alan G; Lam, Wen Jiun; Karunasinghe, Nishi; Campbell, Bobbi; Ferguson, Lynnette R

2012-09-01

New Zealand has one of the highest incidence rates of Crohn's Disease (CD), whilst the serum selenium status of New Zealanders is amongst the lowest in the world. A prospective case-control study in Auckland, New Zealand considered serum selenium as a potential CD risk factor. Serum selenium levels were significantly lower in CD patients compared to controls (101.8 ± 1.02 vs. 111.1 ± 1.01 ng/mL) (p = 5.91 × 10(-8)). Recent detailed studies in the United Kingdom have suggested an optimal serum level around 122 ng/mL, making the average CD patient in New Zealand selenium deficient. Of the 29 single nucleotide polymorphisms (SNPs) tested, 13 were found to significantly interact with serum selenium on CD. After adjustment for multiple testing, a significant interaction with serum selenium on CD was found for three SNPs, namely rs17529609 and rs7901303 in the gene SEPHS1, and rs1553153 in the gene SEPSECS. These three SNPs have not been reported elsewhere as being significantly associated with selenium or CD. It is unclear as to whether lower selenium levels are a cause or an effect of the disease.

Selenium, Selenoprotein Genes and Crohn’s Disease in a Case-Control Population from Auckland, New Zealand

PubMed Central

Gentschew, Liljana; Bishop, Karen S.; Han, Dug Yeo; Morgan, Angharad R.; Fraser, Alan G.; Lam, Wen Jiun; Karunasinghe, Nishi; Campbell, Bobbi; Ferguson, Lynnette R.

2012-01-01

New Zealand has one of the highest incidence rates of Crohn’s Disease (CD), whilst the serum selenium status of New Zealanders is amongst the lowest in the world. A prospective case-control study in Auckland, New Zealand considered serum selenium as a potential CD risk factor. Serum selenium levels were significantly lower in CD patients compared to controls (101.8 ± 1.02 vs. 111.1 ± 1.01 ng/mL) (p = 5.91 × 10−8). Recent detailed studies in the United Kingdom have suggested an optimal serum level around 122 ng/mL, making the average CD patient in New Zealand selenium deficient. Of the 29 single nucleotide polymorphisms (SNPs) tested, 13 were found to significantly interact with serum selenium on CD. After adjustment for multiple testing, a significant interaction with serum selenium on CD was found for three SNPs, namely rs17529609 and rs7901303 in the gene SEPHS1, and rs1553153 in the gene SEPSECS. These three SNPs have not been reported elsewhere as being significantly associated with selenium or CD. It is unclear as to whether lower selenium levels are a cause or an effect of the disease. PMID:23112913

Dietary selenium in adjuvant therapy of viral and bacterial infections.

PubMed

Steinbrenner, Holger; Al-Quraishy, Saleh; Dkhil, Mohamed A; Wunderlich, Frank; Sies, Helmut

2015-01-01

Viral and bacterial infections are often associated with deficiencies in macronutrients and micronutrients, including the essential trace element selenium. In selenium deficiency, benign strains of Coxsackie and influenza viruses can mutate to highly pathogenic strains. Dietary supplementation to provide adequate or supranutritional selenium supply has been proposed to confer health benefits for patients suffering from some viral diseases, most notably with respect to HIV and influenza A virus (IAV) infections. In addition, selenium-containing multimicronutrient supplements improved several clinical and lifestyle variables in patients coinfected with HIV and Mycobacterium tuberculosis. Selenium status may affect the function of cells of both adaptive and innate immunity. Supranutritional selenium promotes proliferation and favors differentiation of naive CD4-positive T lymphocytes toward T helper 1 cells, thus supporting the acute cellular immune response, whereas excessive activation of the immune system and ensuing host tissue damage are counteracted through directing macrophages toward the M2 phenotype. This review provides an up-to-date overview on selenium in infectious diseases caused by viruses (e.g., HIV, IAV, hepatitis C virus, poliovirus, West Nile virus) and bacteria (e.g., M. tuberculosis, Helicobacter pylori). Data from epidemiologic studies and intervention trials, with selenium alone or in combination with other micronutrients, and animal experiments are discussed against the background of dietary selenium requirements to alter immune functions. © 2015 American Society for Nutrition.

A short-term intervention with selenium affects expression of genes implicated in the epithelial-to-mesenchymal transition in the prostate

PubMed Central

Kok, Dieuwertje E.G.; Kiemeney, Lambertus A.L.M.; Verhaegh, Gerald W.; Schalken, Jack A.; van Lin, Emile N.J.T.; Michiel Sedelaar, J.P.; Alfred Witjes, J.; Hulsbergen - van de Kaa, Christina A.; van't Veer, Pieter; Kampman, Ellen; Afman, Lydia A.

2017-01-01

In parallel with the inconsistency in observational studies and chemoprevention trials, the mechanisms by which selenium affects prostate cancer risk have not been elucidated. We conducted a randomized, placebo-controlled trial to examine the effects of a short-term intervention with selenium on gene expression in non-malignant prostate tissue. Twenty-three men received 300 μg selenium per day in the form of selenized yeast (n=12) or a placebo (n=11) during 5 weeks. Prostate biopsies collected from the transition zone before and after intervention were analysed for 15 participants (n=8 selenium, n=7 placebo). Pathway analyses revealed that the intervention with selenium was associated with down-regulated expression of genes involved in cellular migration, invasion, remodeling and immune responses. Specifically, expression of well-established epithelial markers, such as E-cadherin and epithelial cell adhesion molecule EPCAM, was up-regulated, while the mesenchymal markers vimentin and fibronectin were down-regulated after intervention with selenium. This implies an inhibitory effect of selenium on the epithelial-to-mesenchymal transition (EMT). Moreover, selenium was associated with down-regulated expression of genes involved in wound healing and inflammation; processes which are both related to EMT. In conclusion, our explorative data showed that selenium affected expression of genes implicated in EMT in the transition zone of the prostate. PMID:28076331

A short-term intervention with selenium affects expression of genes implicated in the epithelial-to-mesenchymal transition in the prostate.

PubMed

Kok, Dieuwertje E G; Kiemeney, Lambertus A L M; Verhaegh, Gerald W; Schalken, Jack A; van Lin, Emile N J T; Sedelaar, J P Michiel; Witjes, J Alfred; Hulsbergen-van de Kaa, Christina A; van 't Veer, Pieter; Kampman, Ellen; Afman, Lydia A

2017-02-07

In parallel with the inconsistency in observational studies and chemoprevention trials, the mechanisms by which selenium affects prostate cancer risk have not been elucidated. We conducted a randomized, placebo-controlled trial to examine the effects of a short-term intervention with selenium on gene expression in non-malignant prostate tissue. Twenty-three men received 300 µg selenium per day in the form of selenized yeast (n=12) or a placebo (n=11) during 5 weeks. Prostate biopsies collected from the transition zone before and after intervention were analysed for 15 participants (n=8 selenium, n=7 placebo). Pathway analyses revealed that the intervention with selenium was associated with down-regulated expression of genes involved in cellular migration, invasion, remodeling and immune responses. Specifically, expression of well-established epithelial markers, such as E-cadherin and epithelial cell adhesion molecule EPCAM, was up-regulated, while the mesenchymal markers vimentin and fibronectin were down-regulated after intervention with selenium. This implies an inhibitory effect of selenium on the epithelial-to-mesenchymal transition (EMT). Moreover, selenium was associated with down-regulated expression of genes involved in wound healing and inflammation; processes which are both related to EMT. In conclusion, our explorative data showed that selenium affected expression of genes implicated in EMT in the transition zone of the prostate.

Sequential solvent extraction for the modes of occurrence of selenium in coals of different ranks from the Huaibei Coalfield, China

USGS Publications Warehouse

Zhang, Y.; Liu, Gaisheng; Chou, C.-L.; Wang, L.; Kang, Y.

2007-01-01

Forms of selenium in bituminous coal, anthracite, and cokeite (natural coke) from Huaibei Coalfield, Anhui, China, have been determined by sequential solvent extraction. The selenium content in bulk samples is 4.0, 2.4, and 2.0 ??g/g in bituminous coal, anthracite, and cokeite, respectively. The six forms of selenium determined by six-step solvent extraction are water-leachable, ion-exchangeable, organic matter-associated, carbonate-associated, silicate-associated, and sulfide-associated. The predominant forms of selenium in bituminous coal are organic matter-associated (39.0%), sulfide-associated (21.1%), and silicate bound (31.8%); these three forms account for 92% of the total. The organic matter bound-selenium decrease dramatically from bituminous coal (39.0%) to anthracite (11.6%) and to cokeite (0%), indicating that organic matter bound selenium is converted to other forms during metamorphism of the coal, most likely sulfide-form. The sulfide-associated form increased remarkably from bituminous coal (21.1%) to anthracite (50.4%) and cokeite (54.5%), indicating the formation of selenium sulfide, possibly in pyrite during the transformation of bituminous coal to anthracite and cokeite. The silicate-associated selenium in bituminous coal (31.8%) is much higher than that in anthracite (16.4%) and cokeite (15.8%), indicating that silicate-associated selenium is partly converted to sulfide during metamorphism. ?? 2007 Zhang et al; licensee BioMed Central Ltd.

Dietary Selenium in Adjuvant Therapy of Viral and Bacterial Infections12

PubMed Central

Steinbrenner, Holger; Al-Quraishy, Saleh; Dkhil, Mohamed A; Wunderlich, Frank; Sies, Helmut

2015-01-01

Viral and bacterial infections are often associated with deficiencies in macronutrients and micronutrients, including the essential trace element selenium. In selenium deficiency, benign strains of Coxsackie and influenza viruses can mutate to highly pathogenic strains. Dietary supplementation to provide adequate or supranutritional selenium supply has been proposed to confer health benefits for patients suffering from some viral diseases, most notably with respect to HIV and influenza A virus (IAV) infections. In addition, selenium-containing multimicronutrient supplements improved several clinical and lifestyle variables in patients coinfected with HIV and Mycobacterium tuberculosis. Selenium status may affect the function of cells of both adaptive and innate immunity. Supranutritional selenium promotes proliferation and favors differentiation of naive CD4-positive T lymphocytes toward T helper 1 cells, thus supporting the acute cellular immune response, whereas excessive activation of the immune system and ensuing host tissue damage are counteracted through directing macrophages toward the M2 phenotype. This review provides an up-to-date overview on selenium in infectious diseases caused by viruses (e.g., HIV, IAV, hepatitis C virus, poliovirus, West Nile virus) and bacteria (e.g., M. tuberculosis, Helicobacter pylori). Data from epidemiologic studies and intervention trials, with selenium alone or in combination with other micronutrients, and animal experiments are discussed against the background of dietary selenium requirements to alter immune functions. PMID:25593145

The leaching characteristics of selenium from coal fly ashes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, T.; Wang, J.; Burken, J.G.

2007-11-15

The leaching characteristics of selenium from several bituminous and subbituminous coal fly ashes under different pH conditions were investigated using batch methods. Results indicated that pH had a significant effect on selenium leaching from bituminous coal ash. The minimum selenium leaching occurred in the pH range between 3 and 4, while the maximum selenium leaching occurred at pH 12. The release of selenium from subbituminous coal ashes was very low for the entire experimental pH range, possibly due to the high content of calcium which can form hydration or precipitation products as a sink for selenium. The adsorption results formore » different selenium species indicated that Se(VI) was hardly adsorbable on either bituminous coal ashes or subbitumminous coal ashes at any pH. However, Se(I) was highly adsorbed by bituminous coal ashes under acidic pH conditions and was mostly removed by subbitumminous coal ashes across the entire pH range. This result suggests that the majority of selenium released from the tested fly ashes was Se(IV). A speciation-based model was developed to simulate the adsorption of Se(IV) on bituminous coal fly ash, and the pH-independent adsorption constants of HSeO{sup 3-} and SeO{sub 3}{sup 2-} were determined. The modeling approach is useful for understanding and predicting the release process of selenium from fly ash.« less

Analysis of Dissolved Selenium Loading for Selected Sites in the Lower Gunnison River Basin, Colorado, 1978-2005

USGS Publications Warehouse

Thomas, Judith C.; Leib, Kenneth J.; Mayo, John W.

2008-01-01

Elevated selenium concentrations in streams are a water-quality concern in western Colorado. The U.S. Geologic Survey, in cooperation with the Colorado Department of Public Health and Environment, summarized selenium loading in the Lower Gunnison River Basin to support the development of total maximum daily selenium loads at sites that represent the cumulative contribution to U.S. Environmental Protection Agency 303(d) list segments. Analysis of selenium loading included quantifying loads and determining the amount of load that would need to be reduced to bring the site into compliance, referred to as 'the load reduction,' with the State chronic aquatic-life standard for dissolved selenium [85th percentile selenium concentration not to exceed 4.6 ?g/L (micrograms per liter)], referred to as 'the water-quality standard.' Streamflow and selenium concentration data for 54 historical water-quality/water-quantity monitoring sites were compiled from U.S. Geological Survey and Colorado Department of Public Health and Environment data sources. Three methods were used for analysis of selenium concentration data to address the variable data density among sites. Mean annual selenium loads were determined for only 10 of the 54 sites due to data availability limitations. Twenty-two sites had 85th percentile selenium concentrations that exceeded the water-quality standard, 3 sites had 85th percentile selenium concentrations less than the State standard, and 29 sites could not be evaluated with respect to 85th percentile selenium concentration (sample count less than 5). To bring selenium concentrations into compliance with the water-quality standard, more than 80 percent of the mean annual selenium load would need to be reduced at Red Rock Canyon, Dry Cedar Creek, Cedar Creek, Loutzenhizer Arroyo, Sunflower Drain, and Whitewater Creek. More than 50 percent of the mean annual load would need to be reduced at Dry Creek to bring the site into compliance with the water-quality standard. The Uncompahgre River, Gunnison River at Delta, and Gunnison River near Grand Junction would require 69, 34 and 53 percent, respectively, of the mean annual load to be reduced for water years 2001 through 2005 to meet the water-quality standard. Mean annual load reductions can be further reduced by targeting the periods of time when selenium would be removed from streams by remediation. During a previous study of selenium loads in the Lower Gunnison River Basin, mean annual load reductions were estimated at the Gunnison River near Grand Junction for the 1997?2001 study period. Mean annual load reductions estimated for this study period were less than those estimated for the 2001?05 study period, emphasizing the importance of understanding that different study periods can result in different load reduction estimates.

Ecology and Biotechnology of Selenium-Respiring Bacteria

PubMed Central

2015-01-01

SUMMARY In nature, selenium is actively cycled between oxic and anoxic habitats, and this cycle plays an important role in carbon and nitrogen mineralization through bacterial anaerobic respiration. Selenium-respiring bacteria (SeRB) are found in geographically diverse, pristine or contaminated environments and play a pivotal role in the selenium cycle. Unlike its structural analogues oxygen and sulfur, the chalcogen selenium and its microbial cycling have received much less attention by the scientific community. This review focuses on microorganisms that use selenate and selenite as terminal electron acceptors, in parallel to the well-studied sulfate-reducing bacteria. It overviews the significant advancements made in recent years on the role of SeRB in the biological selenium cycle and their ecological role, phylogenetic characterization, and metabolism, as well as selenium biomineralization mechanisms and environmental biotechnological applications. PMID:25631289

Selenium Exposure and Cancer Risk: an Updated Meta-analysis and Meta-regression

PubMed Central

Cai, Xianlei; Wang, Chen; Yu, Wanqi; Fan, Wenjie; Wang, Shan; Shen, Ning; Wu, Pengcheng; Li, Xiuyang; Wang, Fudi

2016-01-01

The objective of this study was to investigate the associations between selenium exposure and cancer risk. We identified 69 studies and applied meta-analysis, meta-regression and dose-response analysis to obtain available evidence. The results indicated that high selenium exposure had a protective effect on cancer risk (pooled OR = 0.78; 95%CI: 0.73–0.83). The results of linear and nonlinear dose-response analysis indicated that high serum/plasma selenium and toenail selenium had the efficacy on cancer prevention. However, we did not find a protective efficacy of selenium supplement. High selenium exposure may have different effects on specific types of cancer. It decreased the risk of breast cancer, lung cancer, esophageal cancer, gastric cancer, and prostate cancer, but it was not associated with colorectal cancer, bladder cancer, and skin cancer. PMID:26786590

Selenium biomineralization for biotechnological applications.

PubMed

Nancharaiah, Yarlagadda V; Lens, Piet N L

2015-06-01

Selenium (Se) is not only a strategic element in high-tech electronics and an essential trace element in living organisms, but also a potential toxin with low threshold concentrations. Environmental biotechnological applications using bacterial biomineralization have the potential not only to remove selenium from contaminated waters, but also to sequester it in a reusable form. Selenium biomineralization has been observed in phylogenetically diverse microorganisms isolated from pristine and contaminated environments, yet it is one of the most poorly understood biogeochemical processes. Microbial respiration of selenium is unique because the microbial cells are presented with both soluble (SeO(4)(2-) and SeO(3)(2-)) and insoluble (Se(0)) forms of selenium as terminal electron acceptor. Here, we highlight selenium biomineralization and the potential biotechnological uses for it in bioremediation and wastewater treatment. Copyright © 2015 Elsevier Ltd. All rights reserved.

Ecology and biotechnology of selenium-respiring bacteria.

PubMed

Nancharaiah, Y V; Lens, P N L

2015-03-01

In nature, selenium is actively cycled between oxic and anoxic habitats, and this cycle plays an important role in carbon and nitrogen mineralization through bacterial anaerobic respiration. Selenium-respiring bacteria (SeRB) are found in geographically diverse, pristine or contaminated environments and play a pivotal role in the selenium cycle. Unlike its structural analogues oxygen and sulfur, the chalcogen selenium and its microbial cycling have received much less attention by the scientific community. This review focuses on microorganisms that use selenate and selenite as terminal electron acceptors, in parallel to the well-studied sulfate-reducing bacteria. It overviews the significant advancements made in recent years on the role of SeRB in the biological selenium cycle and their ecological role, phylogenetic characterization, and metabolism, as well as selenium biomineralization mechanisms and environmental biotechnological applications. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Selenium recovery from kiln powder of cement manufacturing by chemical leaching and bioreduction.

PubMed

Soda, S; Hasegawa, A; Kuroda, M; Hanada, A; Yamashita, M; Ike, M

2015-01-01

A novel process by using chemical leaching followed by bacterial reductive precipitation was proposed for selenium recovery from kiln powder as a byproduct of cement manufacturing. The kiln powder at a slurry concentration of 10 w/v% with 0.25 M Na2CO3 at 28°C produced wastewater containing about 30 mg-Se/L selenium. The wastewater was diluted four-fold and adjusted to pH 8.0 as preconditioning for bioreduction. A bacterial strain Pseudomonas stutzeri NT-I, capable of reducing selenate and selenite into insoluble elemental selenium, could recover about 90% selenium from the preconditioned wastewater containing selenium of 5 mg-Se/L when supplemented with lactate or glycerol. The selenium concentrations in the treated wastewater were low around the regulated effluent concentration of 0.1 mg-Se/L in Japan.

Novel selenium containing boro-phosphate glasses: preparation and structural study.

PubMed

Ciceo-Lucacel, R; Radu, T; Ponta, O; Simon, V

2014-06-01

We synthesized a new boro-phosphate glass system with different %mol SeO2 content by conventional melt quenching technique. All samples were obtained in a glassy state with the vitreous structure confirmed by X-ray diffraction analysis. Scanning electron microscopy (SEM) revealed some non-homogeneous domains on the glasses surface, and their tendency to link each other once the selenium oxide content increases. Energy-dispersive X-ray analysis (EDAX) indicated similar elemental composition in different regions of each sample. X-ray photoelectron spectroscopy (XPS) was used to determine the nature of chemical bonding and the elemental composition at the sample surfaces, and Fourier transform infrared (FT-IR) spectroscopy was used to determine the structural groups in the obtained glass structure. Based on FT-IR results, the glass structure at short range order consists mainly of small phosphate units such as pyrophosphate (i.e. P2O7(4-) dimmers or terminating groups at the end of phosphate chains) and some metaphosphate (i.e. PO3(-) middle groups in the phosphate chains) units. The boron atoms are mainly placed in three-coordinated sites in BØ3 or BØ2O(-) units. A small contribution of BØ4(-) units was also detected from the FT-IR spectra of glasses. For SeO2 content higher than 5mol%, the modifier role of selenium ions is strongly reflected on the local structure dominated in this case by pyrophosphate units. Copyright © 2014 Elsevier B.V. All rights reserved.

Selenium stable isotope investigation into selenium biogeochemical cycling in a lacustrine environment: Sweitzer Lake, Colorado.

PubMed

Clark, Scott K; Johnson, Thomas M

2010-01-01

We present a comprehensive set of Se concentration and isotope ratio data collected over a 3-yr period from dissolved, sediment-hosted, and organically bound Se in a Se-contaminated lake and littoral wetland. Median isotope ratios of these various pools of Se spanned a narrow isotopic range (delta80/76Se(SRM-3149)) = 1.14-2.40 per thousand). Selenium (VI) reduction in the sediments is an important process in this system, but its isotopic impact is muted by the lack of direct contact between surface waters and reduction sites within sediments. This indicates that using Se isotope data as an indicator of microbial or abiotic Se oxyanion reduction is not effective in this or other similar systems. Isotopic data suggest that most Se(IV) in the lake originates from oxidation of organically bound Se rather than directly through Se(VI) reduction. Mobilization of Se(VI) from bedrock involves only a slight isotopic shift. Temporally constant isotopic differences observed in Se(VI) from two catchment areas suggest the potential for tracing Se(VI) from different source areas. Phytoplankton isotope ratios are close to those of the water, with a small depletion in heavy isotopes (0.56 per thousand). Fish tissues nearly match the phytoplankton, being only slightly depleted in the heavier isotopes. This suggests the potential for Se isotopes as migration indicators. Volatile, presumably methylated Se was isotopically very close to median values for phytoplankton and macrophytes, indicating a lack of isotopic fractionation during methylation.

Pre-Antiretroviral Therapy Serum Selenium Concentrations Predict WHO Stages 3, 4 or Death but not Virologic Failure Post-Antiretroviral Therapy

PubMed Central

Shivakoti, Rupak; Gupte, Nikhil; Yang, Wei-Teng; Mwelase, Noluthando; Kanyama, Cecilia; Tang, Alice M.; Pillay, Sandy; Samaneka, Wadzanai; Riviere, Cynthia; Berendes, Sima; Lama, Javier R.; Cardoso, Sandra W.; Sugandhavesa, Patcharaphan; Semba, Richard D.; Christian, Parul; Campbell, Thomas B.; Gupta, Amita

2014-01-01

A case-cohort study, within a multi-country trial of antiretroviral therapy (ART) efficacy (Prospective Evaluation of Antiretrovirals in Resource Limited Settings (PEARLS)), was conducted to determine if pre-ART serum selenium deficiency is independently associated with human immunodeficiency virus (HIV) disease progression after ART initiation. Cases were HIV-1 infected adults with either clinical failure (incident World Health Organization (WHO) stage 3, 4 or death by 96 weeks) or virologic failure by 24 months. Risk factors for serum selenium deficiency (<85 μg/L) pre-ART and its association with outcomes were examined. Median serum selenium concentration was 82.04 μg/L (Interquartile range (IQR): 57.28–99.89) and serum selenium deficiency was 53%, varying widely by country from 0% to 100%. In multivariable models, risk factors for serum selenium deficiency were country, previous tuberculosis, anemia, and elevated C-reactive protein. Serum selenium deficiency was not associated with either clinical failure or virologic failure in multivariable models. However, relative to people in the third quartile (74.86–95.10 μg/L) of serum selenium, we observed increased hazards (adjusted hazards ratio (HR): 3.50; 95% confidence intervals (CI): 1.30–9.42) of clinical failure but not virologic failure for people in the highest quartile. If future studies confirm this relationship of high serum selenium with increased clinical failure, a cautious approach to selenium supplementation might be needed, especially in HIV-infected populations with sufficient or unknown levels of selenium. PMID:25401501

Metals in Devonian kerogenous marine strata at Gibellini and Bisoni properties in southern Fish Creek Range, Eureka County, Nevada

USGS Publications Warehouse

Desborough, George A.; Poole, F.G.; Hose, R.K.; Radtke, A.S.

1979-01-01

A kerogen-rich sequence of siliceous mudstone, siltstone, and chert as much as 60 m thick on ridge 7129 in the southern Fish Creek Range, referred to as Gibellini facies of the Woodruff Formation, has been evaluated on the surface and in drill holes principally for its potential resources of vanadium, zinc, selenium, molybdenum, and syncrude oil content. The strata are part of a strongly deformed allochthonous mass of eugeosynclinal Devonian marine rocks that overlie deformed allochthonous Mississippian siliceous rocks and relatively undeformed autochthonous Mississippian Antler flysch at this locality. The vanadium in fresh black rocks obtained from drill holes and fresh exposures in trenches and roadcuts occurs chiefly in organic matter. Concentrations of vanadium oxide (V2O5) in unoxidized samples range from 3,000 to 7,000 ppm. In oxidized and bleached rock that is prevalent at the surface, concentrations of vanadium oxide range from 6,000 to 8,000 ppm, suggesting a tendency toward enrichment due to surficial weathering and ground-water movement. Zinc occurs in sphalerite, and selenium occurs in organic matter; molybdenum appears to occur both in molybdenite and in organic matter. Concentrations of zinc in unoxidized rock range from 4,000 to 18,000 ppm, whereas in oxidized rock they range from 30 to 100 ppm, showing strong depletion due to weathering. Concentrations of selenium in unoxidized rock range from 30 to 200 ppm, whereas in oxidized rock they range from 200 to 400 ppm, indicating some enrichment upon weathering. Concentrations of molybdenum in unoxidized rock range from 70 to 960 ppm, whereas in oxidized rock they range from 30 to 80 ppm, indicating strong depletion upon weathering. Most fresh black rock is low-grade oil shale, and yields as much as 12 gallons/short ton of syncrude oil. Metahewettite is the principal vanadium mineral in the oxidized zone, but it also occurs sparsely as small nodules and fillings of microfractures in unweathered strata. In fresh rock, bluish-white opaline-like silica (chalcedonic quartz) fills microfractures, and is believed to have originated by diagenetic mobilization of opaline silica from radiolarian tests and sponge spicules. As revealed by microscopic study, the Gibellini facies originally consisted of siliceous muds, slimes, and oozes high in organic constituents. The organic matter is amorphous flaky and stringy sapropel, and probably includes remains of bacteria, phytoplankton, zooplankton, and minor higher plants. Recognizable organic remnants include radiolarian tests, sponge spicules, conodonts, brachiopod shells, algae, and humic debris. Diagnostic radiolarians indicate a Late Devonian age for the Gibellini facies of the Woodruff Formation. Some pyrite is disseminated through the rock and may be primary (syngenetic) but significant pyrite and marcasite occur in chalcedonic quartz veinlets and appear to be diagenetic. In fresh rock, black solid bitumen and liquid oil fill voids and microfractures. These early phase hydrocarbons probably were released during diagenesis from complex nonhydrocarbon molecular structures originating from living organisms, and formed without any major thermal degradation of the kerogen. Gas chromatographic analysis of the saturated hydrocarbon fraction indicates a very complex mixture dominated by branched and cyclic compounds. Conodont and palynomorph color alteration, vitrinite reflectance, and other organic geochemical data suggest that the organic matter in the rock is thermally immature and has not been subjected to temperatures greater than 60?C since deposition in Devonian time. All of these characteristics are consistent with the interpretation of a relatively low temperature and a shallow-burial history for the Gibellini facies on ridge 7129.

Effects of a selenium-laden soil amendment on grapevine metabolism and progression of Pierce’s disease

USDA-ARS?s Scientific Manuscript database

Selenium containing soil amendments might be beneficial to growers as selenium may increase resistance to certain plant pathogens and pests. Therefore, grapevines growing in soil with different amounts of selenium-laden amendment were evaluated for metabolism and susceptibility to Pierce’s disease (...

Encapsulation of selenium in chitosan nanoparticles improves selenium availability and protects cells from selenium-induced DNA damage response

USDA-ARS?s Scientific Manuscript database

Selenium, an essential mineral, plays important roles in optimizing human health. Chitosan is an effective, naturally oriented material for synthesizing nanoparticles with polyanions and exhibit preferable properties such as biocompatibility, biodegradation and resistance to certain enzymes. We have...

Selenium in waters in and adjacent to the Kendrick Project, Natrona County, Wyoming

USGS Publications Warehouse

Crist, Marvin A.

1975-01-01

Selenium in concentrations exceeding the maximum limit, 0.01 milligrams per liter or 10 micrograms per liter, recommended by the U.S. Public Health Service in 'Drinking-Water Standards, 1962,' Public Health Pub. 956, is present in waters in areas near Casper, Wyo. Some streams containing selenium flow into the North Platte River upstream from several municipalities that obtain water from the river and the alluvium along the river. The area of this investigation includes about 725 square miles in Natrona County in central Wyoming. Study effort was most intensive within the area bounded by the North Platte River, Casper Creek, and Casper Canal, the approximate boundaries of the Kendrick irrigation project. Geologic formations in the area contain selenium that may have been derived from deposits of seleniferous material or from volcanic emanations brought down by rain. Formations older than Cretaceous age were not considered as important sources of selenium in waters of the area, because no irrigation water is applied to areas underlain by these rocks. The selenium concentration in 82 samples of Cretaceous rocks ranged from less than 10 to 4,200 ?g/kg (micrograms per kilogram of sample); no correlation was found between selenium concentration and the depth at which the sample was collected. Of four samples of Tertiary rocks analyzed, three contained no selenium and one had a selenium concentration of 40 ?g/kg. The selenium concentration in 93 samples of Quaternary rocks ranged from less than 10 to 52.0 ?g/kg, and the highest selenium concentration was generally found at depths less than 4 feet. No geologic formation has consistently high concentrations of selenium, but high concentrations were found at points throughout the study area. Probably the rocks in any locality could be the source of selenium in the water in the surrounding vicinity. The selenium concentration in water from some wells fluctuates widely. It is concluded that the selenium concentrations in the ground water in these areas have not reached a state of equilibrium in the aquifer. It is possible that such nonequilibrium conditions exist in aquifers throughout much of the area. If so, statements in this report concerning- trends of selenium concentration in ground water are somewhat speculative.Poison Spring Creek, Poison Spider Creek, Oregon Trail Drain, and Casper Creek are the principal tributaries that contribute selenium to the North Platte River. The selenium load, expressed in pounds per day, in Poison Spring Creek and Poison Spider Creek decreased slightly during the first year of sampling and increased slightly during the second year of sampling. The selenium load in Oregon Trail Drain is greatest in late winter and early spring during the period of low flow; the selenium load in Casper Creek varies, but shows no correlation with season and little correlation with stream discharge. The North Platte River above and below the irrigation project had consistently low selenium concentrations, 10 ?g/l (micrograms per liter) or less, in the period April 1968 through June 1969. The total selenium load contributed to the North Platte River from tributaries in the study area is almost undetectable after mixing with the river water. From the fall of 1968 .to the spring of 1969, results of water sampling in areas influenced by irrigation show that the selenium concentration increased at 29 percent of the locations (average net increase of 64 ?g/l), decreased at 34 percent of the locations (average net decrease of 80 ?g/l), and had little (10 ?g/l or .less) or no change at 37 percent of the locations. As a comparison, results of water sampling in areas not influenced by irrigation showed that the selenium concentration increased at 2 percent of the locations (average net increase of 30 ?g/l), decreased at 26 percent of the locations (average net decrease of 30?g/l), and had little or no change at 72 percent of the locations. It is not possible to

Selenium nanomaterials: applications in electronics, catalysis and sensors.

PubMed

Chaudhary, Savita; Mehta, S K

2014-02-01

This review provides insights into the synthesis, functionalization, and applications of selenium nanoparticles in electronics, optics, catalysis and sensors. The variation of physicochemical properties such as particle size, surface area, and shape of the selenium nanoparticles and the effect of experimental conditions has also been discussed. An overview has also been provided on the fundamental electrical and optical properties of selenium nanomaterials as well as their utilization in different research fields. The work presents an insight on selenium nanoparticles with interesting properties and their future applications.

Selenium concentrations in irrigation drain inflows to the Salton Sea, California, October 2006 and January 2007

USGS Publications Warehouse

May, Thomas W.; Walther, Mike W.; Brumbaugh, William G.

2007-01-01

This report presents raw data on selenium concentrations in samples of water, sediment, detritus, and selected food-chain matrices collected from selected agricultural drains in the southern portion of the Salton Sea during October 2006 and January 2007. Total selenium and selenium species were determined in water samples, whereas total selenium was determined in sediment, detritus, algae, plankton, midge larvae (Family Chironomidae), and two fish species (western mosquitofish, Gambusia affinis, and sailfin molly, Poecilia latipinna).

Selenium in foods produced and consumed in Greece

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bratakos, M.S.; Zafiropoulos, T.F.; Siskos, P.A.

The total selenium within a wide variety (315 food items) of Greek foods was determined fluorimetrically. Rich selenium sources were the proteinaceous foods such as fish, meat, bread, and spaghetti. Butter, oils, vegetables, and fruits were poor sources. The selenium content of Greek foods was lower than that of many other countries and resembled more closely that of British foods. From available food consumption data and values in this study, it was estimated that the daily selenium intake of Greeks was 110 {mu}g.