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Sample records for activity selenium speciation

  1. Selenium speciation in ground water

    SciTech Connect

    Atalay, A.

    1990-07-10

    Selenium toxicity diseases in animals may occur when the intake exceeds 4 mg/kg and selenium deficiency symptoms may occur when dietary intake is less than 0.04 mg/kg. Since the selenium dietary requirement is very close to toxic concentration, it is important to understand the distribution of selenium in the environment. Selenium occurs in four oxidation states (-II, 0, +IV, and +VI) as selenide, elemental selenium, selenite and selenate. Selenate is reported as more soluble and less adsorbed than selenite. Selenate is more easily leached from soils and is the most available form for plants. Increased mobility of Se into the environment via anthropogenic activities, and the potential oxidation-reduction behavior of the element have made it imperative to study the aquatic chemistry of Se. For this purpose, Se species are divided into two different categories: dissolved Se (in material that passes through filters with 0.45 u openings) and particulate Se (in material of particle size > 0.45 mm) typically suspended sediment and other suspended solids. Element and colloidal phase, not truly dissolved, but passing through the filter is deemed to consist of selenium (-2,0). In dissolved state selenium may exist in three of its four oxidation states; Se(-II), Se(+IV), and Se(+VI). Particulate Se may exist in the same oxidation states as dissolved Se and can be found in different phases of the particulate matter. In sediments, Se may be within the organic material, iron and manganese oxides, carbonates or other mineral phases. The actual chemical forms of Se may be adsorbed to or coprecipitated with these phases (primarily selenite, SeO{sub 3}{sup 2{minus}}) and selenate, SeO{sub 4}{sup 2{minus}}. Selenide, Se(-II), can be covalently bound in the organic portion of a sediment. In addition, Se may be found in anoxic sediments as insoluble metal selenide precipitates, an insoluble elemental Se or as ferroselite (FeSe{sub 2}) and Se containing pyrite.

  2. Selenium Speciation and Management in Wet FGD Systems

    SciTech Connect

    Searcy, K; Richardson, M; Blythe, G; Wallschlaeger, D; Chu, P; Dene, C

    2012-02-29

    This report discusses results from bench- and pilot-scale simulation tests conducted to determine the factors that impact selenium speciation and phase partitioning in wet FGD systems. The selenium chemistry in wet FGD systems is highly complex and not completely understood, thus extrapolation and scale-up of these results may be uncertain. Control of operating parameters and application of scrubber additives have successfully demonstrated the avoidance or decrease of selenite oxidation at the bench and pilot scale. Ongoing efforts to improve sample handling methods for selenium speciation measurements are also discussed. Bench-scale scrubber tests explored the impacts of oxidation air rate, trace metals, scrubber additives, and natural limestone on selenium speciation in synthetic and field-generated full-scale FGD liquors. The presence and concentration of redox-active chemical species as well as the oxidation air rate contribute to the oxidation-reduction potential (ORP) conditions in FGD scrubbers. Selenite oxidation to the undesirable selenate form increases with increasing ORP conditions, and decreases with decreasing ORP conditions. Solid-phase manganese [Mn(IV)] appeared to be the significant metal impacting the oxidation of selenite to selenate. Scrubber additives were tested for their ability to inhibit selenite oxidation. Although dibasic acid and other scrubber additives showed promise in early clear liquor (sodium based and without calcium solids) bench-scale tests, these additives did not show strong inhibition of selenite oxidation in tests with higher manganese concentrations and with slurries from full-scale wet FGD systems. In bench-tests with field liquors, addition of ferric chloride at a 250:1 iron-to-selenium mass ratio sorbed all incoming selenite to the solid phase, although addition of ferric salts had no impact on native selenate that already existed in the field slurry liquor sample. As ORP increases, selenite may oxidize to selenate more

  3. Mercury modulates selenium activity via altering its accumulation and speciation in garlic (Allium sativum).

    PubMed

    Zhao, Jiating; Hu, Yi; Gao, Yuxi; Li, Yufeng; Li, Bai; Dong, Yuanxing; Chai, Zhifang

    2013-06-01

    Combined pollution of selenium (Se) and mercury (Hg) has been known in Wanshan district (Guizhou Province, China). A better understanding of how Se and Hg interact in plants and the phytotoxicity thereof will provide clues about how to avoid or mitigate adverse effects of Se/Hg on local agriculture. In this study, the biological activity of Se has been investigated in garlic with or without Hg exposure. Se alone can promote garlic growth at low levels (<0.1 mg L(-1)), whereas it inhibits garlic growth at high levels (>1 mg L(-1)). The promotive effect of Se in garlic can be enhanced by low Hg exposure (<0.1 mg L(-1)). When both Se and Hg are at high levels, there is a general antagonistic effect between these two elements in terms of phytotoxicity. Inductively coupled plasma mass spectrometry (ICP-MS) data suggest that Se is mainly concentrated in garlic roots, compared to the leaves and the bulbs. Se uptake by garlic in low Se medium (<0.1 mg L(-1)) can be significantly enhanced as Hg exposure levels increase (P < 0.05), while it can be inhibited by Hg when Se exposure levels exceed 1 mg L(-1). The synchrotron radiation X-ray fluorescence (SRXRF) mapping further shows that Se is mainly concentrated in the stele of the roots, bulbs and the veins of the leaves, and Se accumulation in garlic can be reduced by Hg. The X-ray absorption near edge structure (XANES) study indicates that Se is mainly formed in C-Se-C form in garlic. Hg can decrease the content of inorganic Se mainly in SeO3(2-) form in garlic while increasing the content of organic Se mainly in C-Se-C form (MeSeCys and its derivatives). Hg-mediated changes in Se species along with reduced Se accumulation in garlic may account for the protective effect of Hg against Se phytotoxicity. PMID:23765168

  4. Selenium speciation in ground water. Quarterly report

    SciTech Connect

    Atalay, A.

    1990-07-10

    Selenium toxicity diseases in animals may occur when the intake exceeds 4 mg/kg and selenium deficiency symptoms may occur when dietary intake is less than 0.04 mg/kg. Since the selenium dietary requirement is very close to toxic concentration, it is important to understand the distribution of selenium in the environment. Selenium occurs in four oxidation states (-II, 0, +IV, and +VI) as selenide, elemental selenium, selenite and selenate. Selenate is reported as more soluble and less adsorbed than selenite. Selenate is more easily leached from soils and is the most available form for plants. Increased mobility of Se into the environment via anthropogenic activities, and the potential oxidation-reduction behavior of the element have made it imperative to study the aquatic chemistry of Se. For this purpose, Se species are divided into two different categories: dissolved Se (in material that passes through filters with 0.45 u openings) and particulate Se (in material of particle size > 0.45 mm) typically suspended sediment and other suspended solids. Element and colloidal phase, not truly dissolved, but passing through the filter is deemed to consist of selenium (-2,0). In dissolved state selenium may exist in three of its four oxidation states; Se(-II), Se(+IV), and Se(+VI). Particulate Se may exist in the same oxidation states as dissolved Se and can be found in different phases of the particulate matter. In sediments, Se may be within the organic material, iron and manganese oxides, carbonates or other mineral phases. The actual chemical forms of Se may be adsorbed to or coprecipitated with these phases (primarily selenite, SeO{sub 3}{sup 2{minus}}) and selenate, SeO{sub 4}{sup 2{minus}}. Selenide, Se(-II), can be covalently bound in the organic portion of a sediment. In addition, Se may be found in anoxic sediments as insoluble metal selenide precipitates, an insoluble elemental Se or as ferroselite (FeSe{sub 2}) and Se containing pyrite.

  5. 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. PMID:23578637

  6. Selenium speciation in flue desulfurization residues.

    PubMed

    Zhong, Liping; Cao, Yan; Li, Wenying; Xie, Kechang; Pan, Wei-Ping

    2011-01-01

    Flue gas from coal combustion contains significant amounts of volatile selenium (Se). The capture of Se in the flue gas desulfurization (FGD) scrubber unit has resulted in a generation of metal-laden residues. It is important to determine Se speciation to understand the environmental impact of its disposal. A simple method has been developed for selective inorganic Se(IV), Se(VI) and organic Se determination in the liquid-phase FGD residues by hydride generation atomic fluorescence spectrometry (AFS). It has been determined that Se(IV), Se(VI) and organic Se can be accurately determined with detection limits (DL) of 0.05, 0.06 and 0.06 microg/L, respectively. The accuracy of the proposed method was evaluated by analyzing the certified reference material, NIST CRM 1632c, and also by analyzing spiked tap-water samples. Analysis indicates that the concentration of Se is high in FGD liquid residues and primarily exists in a reduced state as selenite (Se(IV)). The toxicity of Se(IV) is the strongest of all Se species. Flue gas desulfurization residues pose a serious environmental risk. PMID:21476358

  7. SPECIATION OF SELENIUM COMPOUNDS FROM HIGH SELENIUM BROCCOLI IS AFFECTED BY THE EXTRACTING SOLUTION

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The speciation of selenium compounds from high selenium broccoli (876 ¿g/g) depends on the extraction conditions. Twenty-seven extraction conditions were explored involving nine different buffering systems between pH 1 and pH 9. In non-buffered extractions of broccoli, more than 40% of the spiked ...

  8. The relationship of selenium tolerance and speciation in Lecythidaceae species.

    PubMed

    Németh, Anikó; García Reyes, Juan Francisco; Kosáry, Judit; Dernovics, Mihály

    2013-12-01

    Comparative study of selenium (Se) speciation in hyperaccumulator plants offers an interesting challenge from the analytical point of view. In our study the application of a sophisticated sample clean-up procedure and the combination of elemental and molecular mass spectrometric methods led to the identification of several new selenocompounds. The difference between the Se speciation of the primary accumulator Lecythis minor and the secondary accumulator Bertholletia excelsa confirmed the current opinion that the speciation pattern in hyperaccumulator plants is principally related to the mechanism of accumulation and not to taxonomy. The most abundant new selenocompounds were found to be the derivatives of selenohomocysteine (SeHCy) and selenomethionine (SeMet), including fatty acid metabolism related compounds. A series of SeHCy derived species containing multiple Se atoms (>2) was also detected and their structures were validated by the synthesis of their S-Se analogues. PMID:24136350

  9. Thiolated eggshell membranes sorb and speciate inorganic selenium.

    PubMed

    Yang, Ting; Chen, Ming-Li; Hu, Xian-Wei; Wang, Zhao-Wen; Wang, Jian-Hua; Dasgupta, Purnendu K

    2011-01-01

    Eggshell membranes (ESMs) provide a unique, disulfide bond-rich surface. Thioglycolate reduction was used to generate thiol (-SH) groups on the ESM surface by S-S bond cleavage. The thiol-bearing ESMs (TESMs) were characterized by scanning electron microscopy and Raman spectroscopy. The fibrous network structure of the ESM is retained in the TESMs. TESMs adsorb both Se(IV) and Se(VI) but by different mechanisms: Se(VI) is retained reversibly, possibly via ionic interactions, while Se(IV) is reduced to Se(0) and deposited. We thus demonstrate speciation of selenium species, by using samples (a) as such and after prior oxidation to Se(VI), (b) preconcentration on a TESM microcolumn, (c) elution by 0.5 M HNO(3) that only elutes Se(VI) and (d) detection by graphite furnace atomic absorption spectrometry (GFAAS). The Se(IV) amount is determined by difference. For a 1.0 mL sample, the enrichment factor was 17.2, the S/N = 3 detection limit was 0.06 μg L(-1) and the precision was 3.3% at 0.50 μg L(-1). The linear range was 0.25-2.50 μg L(-1). The procedure was validated by analyzing selenium in certified reference materials of human hair (GBW 09101) and rice (GBW 10010). We further demonstrate utility by speciation of inorganic selenium in a series of water samples. PMID:20877887

  10. Speciation of selenium in stream insects using X-ray absorption spectroscopy

    SciTech Connect

    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). Selenium 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.

  11. Speciation of Selenium in Stream Insects Using X-Ray Absorption Spectroscopy

    SciTech Connect

    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). Selenium 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.

  12. SPECIATION OF SELENIUM(IV) AND SELENIUM(VI) USING COUPLED ION CHROMATOGRAPHY: HYDRIDE GENERATION ATOMIC ABSORPTION SPECTROMETRY

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A simple method was developed to speciate inorganic selenium in the microgram per liter range using coupled ion chromatography-hydride generation atomic absorption spectrometry. Because of the differences in toxicity and adsorption behavior, determination of the redox states selenite, Se(IV), and s...

  13. Consequences of vapor enhancement on selenium speciation analysis by HPLC/ICPMS.

    PubMed

    Juresa, Dijana; Kuehnelt, Doris; Francesconi, Kevin A

    2006-12-15

    Recent work has shown the presence of volatile selenium metabolites in human urine and suggested that these compounds could compromise quantitative selenium analyses by ICPMS. We show that with a commonly used sample introduction system (pneumatic nebulizer and spray chamber), two volatile selenium species recently identified in urine, namely, dimethyl selenide and dimethyl diselenide, gave greatly increased ICPMS responses (up to 58-fold) relative to selenite, an effect related to their volatilization in the spray chamber resulting in enhanced transport to the plasma. The quantitative consequences of this effect were demonstrated by measurement of total selenium and selenium species in certified reference material, NIES CRM 18 human urine. Direct flow injection analysis of the urine gave a total selenium concentration more than 2-fold higher than the certified value. These data suggested that NIES CRM 18 may contain part of its selenium as volatile species, and subsequent reversed-phase HPLC/ICPMS showed the presence of dimethyl selenide in addition to selenosugars and trimethylselenonium ion. Although the practice of quantifying unidentified chromatographic peaks against those of known compounds is common in speciation analysis, this approach when applied to NIES CRM 18 gave a value for the sum of selenium species which was twice the certified total selenium concentration. This work shows that the presence of volatile selenium species in urine precludes the use of flow injection analysis for total selenium measurements and imposes severe restrictions on the quantification of urinary selenium metabolites. In addition, it raises broader issues of the validity of the "dilute and shoot" approach to the determination of metals in clinical analysis of biological fluids. PMID:17165855

  14. Selenium speciation and extractability in Dutch agricultural soils.

    PubMed

    Supriatin, Supriatin; Weng, Liping; Comans, Rob N J

    2015-11-01

    The study aimed to understand selenium (Se) speciation and extractability in Dutch agricultural soils. Top soil samples were taken from 42 grassland fields and 41 arable land fields in the Netherlands. Total Se contents measured in aqua regia were between 0.12 and 1.97 mg kg(-1) (on average 0.58 mg kg(-1)). Organic Se after NaOCl oxidation-extraction accounted for on average 82% of total Se, whereas inorganic selenite (selenate was not measurable) measured in ammonium oxalate extraction using HPLC-ICP-MS accounted for on average 5% of total Se. The predominance of organic Se in the soils is supported by the positive correlations between total Se (aqua regia) and total soil organic matter content, and Se and organic C content in all the other extractions performed in this study. The amount of Se extracted followed the order of aqua regia > 1 M NaOCl (pH8) > 0.1 M NaOH>ammonium oxalate (pH3) > hot water>0.43 M HNO3 > 0.01 M CaCl2. None of these extractions selectively extracts only inorganic Se, and relative to other extractions 0.43 M HNO3 extraction contains the lowest fraction of organic Se, followed by ammonium oxalate extraction. In the 0.1M NaOH extraction, the hydrophobic neutral (HON) fraction of soil organic matter is richer in Se than in the hydrophilic (Hy) and humic acid (HA) fractions. The organic matter extracted in 0.01 M CaCl2 and hot water is in general richer in Se compared to the organic matter extracted in 0.1M NaOH, and other extractions (HNO3, ammonium oxalate, NaOCl, and aqua regia). Although the extractability of Se follows to a large extent the extractability of soil organic carbon, there is several time variations in the Se to organic C ratios, reflecting the changes in composition of organic matter extracted. PMID:26093220

  15. Selenium concentration, speciation and behavior in surface waters of the Canadian prairies.

    PubMed

    Hu, Xiaoxi; Wang, Feiyue; Hanson, Mark L

    2009-11-01

    Similar to the San Joaquin Valley of California, the Canadian prairies are underlain with seleniferous shale and have recently witnessed a significant expansion in irrigated agriculture. The irrigated acreage in the prairies is expected to further increase due to global warming and changes in human use patterns. This raises concerns over potential selenium (Se) contamination in prairie surface waters and risk of adverse biological effects. To test the potential for elevated Se in the prairies, Se concentrations and speciation were examined in surface water, sediments, and sediment porewater in three water bodies in southern Manitoba, Canada, along a north-south transect with a gradient of irrigation and agricultural activities. A selenite addition experiment was also performed in mesocosms in a prairie wetland to assess the risk of increasing Se loading to the prairie waters. Overall, our results indicate that Se concentrations in the prairie waters of southern Manitoba are presently low except during the snowmelt season, that Se speciation is dominated by selenate which is of lower toxicity than selenite, and that if additional selenite is discharged into the prairie waters, it will be quickly removed from the surface water to the sediment. The low Se risk in the Canadian prairies is attributed to high soil drainability and relatively small scale of irrigation at present. The Se problem as being experienced in central California is thus unlikely to occur in surface waters of the Canadian prairies, although Se contamination in ground water is possible should the irrigated acreage continue to increase. PMID:19732939

  16. SPECIATION OF SELENIUM AND ARSENIC COMPOUNDS BY CAPILLARY...

    EPA Science Inventory

    Capillary electrophoresis (CE) with hydride generation inductively coupled plasma mass spectrometry was used to determine four arsenicals and two selenium species. Selenate (SeVI) was reduced on-line to selenite (SeIV) by mixing the CE effluent with concentrated HCl. A microporou...

  17. Evaluation of redox condition by selenium speciation coprecipitated with barite

    NASA Astrophysics Data System (ADS)

    Tokunaga, K.; Takahashi, Y.; Yokoyama, Y.; Omori, E.; Kawagucci, S.

    2012-12-01

    Redox potential (Eh) is an important factor controlling chemical processes in hydrosphere on the earth, because redox reactions are related to the behaviors of many major and minor species in natural waters. The Eh may be estimated by the information of the oxidation states of redox couples (e.g., Fe(II)/Fe(III) ratio) since the Eh value tends to be controlled by the major elements. In this study, we suggest to use selenium (Se) in barite (BaSO4) as a redox indicator for hydrothermal system where barite is precipitated. Barite is stable under a high P-T condition, and this mineral contains various trace elements that may reflect the physicochemical condition of the seawater and hydrothermal water where they were formed. Selenium can occur in the environment in several oxidation states (-2, 0, +4 and +6), but Se in natural waters is mostly found in inorganic forms as oxyanions of selenite [Se(IV)] or selenate [Se(VI)]. The valence ratio of Se depends on the redox condition. Selenium is often found in minerals by substituting a site of sulfur (S) since they are homologous element. Both Se(IV) and Se(VI) may be incorporated into barite because barite is stable under a wide range of the Eh-pH condition which includes Se(IV)-Se(VI) boundary in the Eh-pH diagram. Therefore, the oxidation state of Se in barite can provide more precise information on the redox condition of the depositional environment. The purpose of this study is to establish a method to estimate the redox condition where barite is precipitated. Coprecipitation experiments of Se with barite were conducted to clarify the relationships between Se(VI)/Se(VI) ratio in artificial seawater (ASW) and that in barite at pH 8.0 and pH 4.0. These experiments were employed to evaluate the relationship between aqueous Se(VI) fraction (RwVI) and that incorporated into barite (RbVI). The initial pH of ASW was adjusted to 4.0 and 8.0 before the barite precipitation. These two pH conditions were adopted considering

  18. Selenium speciation in framboidal and euhedral pyrites in shales.

    PubMed

    Matamoros-Veloza, Adriana; Peacock, Caroline L; Benning, Liane G

    2014-08-19

    The release of Se from shales is poorly understood because its occurrence, distribution, and speciation in the various components of shale are unknown. To address this gap we combined bulk characterization, sequential extractions, and spatially resolved μ-focus spectroscopic analyses and investigated the occurrence and distribution of Se and other associated elements (Fe, As, Cr, Ni, and Zn) and determined the Se speciation at the μ-scale in typical, low bulk Se containing shales. Our results revealed Se primarily correlated with the pyrite fraction with exact Se speciation highly dependent on pyrite morphology. In euhedral pyrites, we found Se(-II) substitutes for S in the mineral structure. However, we also demonstrate that Se is associated with framboidal pyrite grains as a discrete, independent FeSex phase. The presence of this FeSex species has major implications for Se release, because FeSex species oxidize much faster than Se substituted in the euhedral pyrite lattice. Thus, such an FeSex species will enhance and control the dynamics of Se weathering and release into the aqueous environment. PMID:25032506

  19. A review of recent developments in the speciation and location of arsenic and selenium in rice grain.

    PubMed

    Carey, Anne-Marie; Lombi, Enzo; Donner, Erica; de Jonge, Martin D; Punshon, Tracy; Jackson, Brian P; Guerinot, Mary Lou; Price, Adam H; Meharg, Andrew A

    2012-04-01

    Rice is a staple food yet is a significant dietary source of inorganic arsenic, a class 1, nonthreshold carcinogen. Establishing the location and speciation of arsenic within the edible rice grain is essential for understanding the risk and for developing effective strategies to reduce grain arsenic concentrations. Conversely, selenium is an essential micronutrient and up to 1 billion people worldwide are selenium-deficient. Several studies have suggested that selenium supplementation can reduce the risk of some cancers, generating substantial interest in biofortifying rice. Knowledge of selenium location and speciation is important, because the anti-cancer effects of selenium depend on its speciation. Germanic acid is an arsenite/silicic acid analogue, and location of germanium may help elucidate the mechanisms of arsenite transport into grain. This review summarises recent discoveries in the location and speciation of arsenic, germanium, and selenium in rice grain using state-of-the-art mass spectrometry and synchrotron techniques, and illustrates both the importance of high-sensitivity and high-resolution techniques and the advantages of combining techniques in an integrated quantitative and spatial approach. PMID:22159463

  20. Selenium compounds activate early barriers of tumorigenesis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Selenium chemoprevention by apoptosis has been well studied, but it is not clear whether selenium can activate early barriers of tumorigenesis, namely senescence and DNA damage response. To address this issue, we treated normal and cancerous cells with a gradient concentration of sodium selenite, me...

  1. Distribution and speciation of selenium in the black shale of the Dogger aquifer in the Poitiers Experimental Hydrogeological Site

    NASA Astrophysics Data System (ADS)

    Bassil, Joseph; Naveau, Aude; Di Tullo, Pamela; Grasset, Laurent; Bodin, Jacques; Razack, Moumtaz; Kazpard, Véronique

    2014-05-01

    Selenium (Se) is an element having the narrowest range between dietary deficiency and toxic concentrations. In the environment, selenium has four oxidation states (-II, 0, IV and VI) and has a complex biogeochemical cycle. The European and French legislations fixed 10 µg/L as safe upper limit in drinking water. In several French regions2, selenium concentrations above the limit were detected in groundwater. This poses a problem for local authorities which are obliged to stop the exploitation of many wells. In the north flank of the "Seuil du Poitou", Selenium concentrations above 10 ppb were measured in groundwater samples collected from five wells of the Poitiers Experimental Hydrogeological Site (SEH), which investigates a 100 m carbonate aquifer (Dogger). Total rock analysis applied on samples representing all the geological facies observed in the SEH show that selenium is concentrated in the black clays that fulfill some karst cavities; these clays are thought considered as the main selenium source in the Dogger Aquifer. The main objective of this work is to study the distribution and the speciation of selenium in the geological matrix and the release mechanisms of Se in order to provide quantifiable data to numerical modeling of selenium's reactive flows across the aquifer. The distribution and the speciation of selenium in these black clays were studied by applying parallel and sequential chemical extractions and by verifying the impact of these extractions on the solid dissolution and organic matter mobilization. In all the extractions, the total dissolved selenium was quantified using ICP-MS and the selenium speciation in the aqueous phase by HPLC-ICP-MS. Verifying the impact of the extractions on the solid dissolution and on the organic matter mobilization was performed by measuring Al, Si, Fe and Ca by AAS and the Total Organic Carbon TOC and by acquisition of XRD diffractograms of the solid residues. Our results showed that most of the selenium is

  2. Speciation of arsenic(III)/arsenic(V) and selenium(IV)/ selenium(VI) using coupled ion chromatography - hydride generation atomic absorption spectrometry

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Simple analytical methods have been developed to speciate inorganic arsenic and selenium in the ppb range using coupled ion chromatography-hydride generation atomic absorption spectrometry. Because of the differences in toxicity and adsorption behavior, determinations of the redox states arsenite A...

  3. Speciation and Attenuation of Arsenic and Selenium at Coal Combustion By-Product Management Facilities

    SciTech Connect

    K. Ladwig

    2005-12-31

    The overall objective of this project was to evaluate the impact of key constituents captured from power plant air streams (principally arsenic and selenium) on the disposal and utilization of coal combustion products (CCPs). Specific objectives of the project were: (1) to develop a comprehensive database of field leachate concentrations at a wide range of CCP management sites, including speciation of arsenic and selenium, and low-detection limit analyses for mercury; (2) to perform detailed evaluations of the release and attenuation of arsenic species at three CCP sites; and (3) to perform detailed evaluations of the release and attenuation of selenium species at three CCP sites. Each of these objectives was accomplished using a combination of field sampling and laboratory analysis and experimentation. All of the methods used and results obtained are contained in this report. For ease of use, the report is subdivided into three parts. Volume 1 contains methods and results for the field leachate characterization. Volume 2 contains methods and results for arsenic adsorption. Volume 3 contains methods and results for selenium adsorption.

  4. Selenium speciation in malt, wort, and beer made from selenium-biofortified two-rowed barley grain.

    PubMed

    Rodrigo, Sara; Santamaria, Oscar; Chen, Yi; McGrath, Steve P; Poblaciones, Maria J

    2014-06-25

    Selenium (Se) biofortification of barley is a suitable strategy to increase the Se concentration in grain. In the present paper, the suitability of this Se-biofortified grain for making Se-enriched beer is analyzed. The aim of the present study was to evaluate the effect of different Se fertilizer doses (0, 10, and 20 g of Se ha(-1)) and forms (sodium selenate or sodium selenite) on the Se loss during the malting and brewing processes and Se speciation in grain, malt, wort, and beer. Samples were analyzed using inductively coupled plasma-mass spectrometry (ICP-MS) and high-performance liquid chromatography (HPLC)-ICP-MS for total Se and speciation. Mashing-lautering was the process with the greatest Se loss (83.8%). After malting and brewing, only 7.3% of the initial Se was retained in beer, mainly in selenite form. Even so, the fertilizer application of sodium selenate at 20 g ha(-1) increased the total Se concentration almost 6-fold in the final beer in comparison to the use of grain derived from unfertilized barley. The present paper provides evidence that the use of Se-biofortified barley grain as a raw material to produce Se-enriched beer is possible, and the results are comparable to other methods in terms of efficiency. PMID:24869769

  5. Selenium And Arsenic Speciation in Fly Ash From Full-Scale Coal-Burning Utility Plants

    SciTech Connect

    Huggins, F.E.; Senior, C.L.; Chu, P.; Ladwig, K.; Huffman, G.P.; /Kentucky U. /Reaction Engin. Int. /Elect. Power Res. Inst., Palo Alto

    2007-07-09

    X-ray absorption fine structure spectroscopy has been used to determine directly the oxidation states and speciation of selenium and arsenic in 10 fly ash samples collected from full-scale utility plants. Such information is needed to assess the health risk posed by these elements in fly ash and to understand their behavior during combustion and in fly ash disposal options, such as sequestration in tailings ponds. Selenium is found predominantly as Se(IV) in selenite (SeO{sub 3}{sup 2-}) species, whereas arsenic is found predominantly as As(V) in arsenate (AsO{sub 4}{sup 3-}) species. Two distinct types of selenite and arsenate spectra were observed depending upon whether the fly ash was derived from eastern U.S. bituminous (Fe-rich) coals or from western subbituminous or lignite (Ca-rich) coals. Similar spectral details were observed for both arsenic and selenium in the two different types of fly ash, suggesting that the post-combustion behavior and capture of both of these elements are likely controlled by the same dominant element or phase in each type of fly ash.

  6. Selenium speciation analysis of Misgurnus anguillicaudatus selenoprotein by HPLC-ICP-MS and HPLC-ESI-MS/MS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Analytical methods for selenium (Se) speciation were developed using high performance liquid chromatography (HPLC) coupled to either inductively coupled plasma mass spectrometry (ICP-MS) or electrospray ionization tandem mass spectrometry (ESI-MS/MS). Separations of selenomethionine (Se-Met) and sel...

  7. Fertilizing soil with selenium fertilizers: impact on concentration, speciation, and bioaccessibility of selenium in leek (Allium ampeloprasum).

    PubMed

    Lavu, Rama V Srikanth; Du Laing, Gijs; Van de Wiele, Tom; Pratti, Varalakshmi L; Willekens, Koen; Vandecasteele, Bart; Tack, Filip

    2012-11-01

    Leek was fertilized with sodium selenite (Na(2)SeO(3)) and sodium selenate (Na(2)SeO(4)) in a green house to assess the impact of selenium (Se) fertilization on Se uptake by the crop and its speciation in the crop. The bioaccessibility of Se in the Se-enriched leek was assessed using an in vitro extraction protocol mimicking the human gastrointestinal tract (stomach, small intestine, and colon). The lowest Se uptake was observed when Na(2)SeO(3) was used as a fertilizer, which results in a higher risk for Se accumulation in the soil on a longer term. When soil was amended with Na(2)SeO(4), 55 ± 5% of total Se in the leek occurred in an inorganic form, while only 21 ± 8% was inorganic when Na(2)SeO(3) was applied. Se-methylselenocysteine and selenomethione were the major organic species in both treatments. However, concentrations of Se-methylselenocysteine and γ-glutamyl-Se-methyl-selenocysteine, which were previously reported to induce positive health effects, were lower as compared to other Allium species. The majority of the Se in the leek was found to be bioaccessible in the stomach (around 60%) and small intestine (around 80%). However, a significant fraction also has good chances to reach the colon, where it seems to be taken up by the microbial community and may also induce positive health effects. PMID:23078411

  8. Selenium

    MedlinePlus

    ... depends on the amount of selenium in the soil where they were grown. The amount of selenium ... raised in many different areas, including areas with soil that is rich in selenium. Certain groups of ...

  9. Speciation of Selenium, Arsenic, and Zinc in Class C Fly Ash

    SciTech Connect

    Luo, Yun; Giammar, Daniel E.; Huhmann, Brittany L.; Catalano, Jeffrey G.

    2011-11-17

    A major environmental concern associated with coal fly ash is the mobilization of trace elements that may contaminate water. To better evaluate proper use of fly ash, determine appropriate disposal methods, and monitor postdisposal conditions, it is important to understand the speciation of trace elements in fly ash and their possible environmental impact. The speciation of selenium, arsenic, and zinc was determined in five representative Class C fly ash samples from combustion of sub-bituminous Powder River Basin coal using synchrotron-based X-ray absorption spectroscopy to provide an improved understanding of the mechanisms of trace element association with the fly ash. Selenium in all fly ash samples occurs predominantly as Se(IV), with the exception of one sample, in which there was a minor amount of Se(0). Se(0) is likely associated with the high content of unburned coal in the sample. Arsenic exists in the fly ash as a single phase most consistent with calcium pyroarsenate. In contrast, zinc occurs as two distinct species in the silicate glass matrix of the fly ash. This work demonstrates that residual carbon in fly ash may reduce potential Se mobility in the environment by retaining it as less soluble elemental Se instead of Se(IV). Further, this work suggests that As and Zn in Class C fly ash will display substantially different release and mobilization behaviors in aquatic environments. While As release will primarily depend upon the dissolution and hydrolysis of calcium pyroarsenate, Zn release will be controlled by the dissolution of alkaline aluminosilicate glass in the ash.

  10. Speciation and Attenuation of Arsenic and Selenium at Coal Combustion By-Product Management Facilities

    SciTech Connect

    K. Ladwig; B. Hensel; D. Wallschlager; L. Lee; I Murarka

    2005-10-19

    Field leachate samples are being collected from coal combustion product (CCP) management sites from several geographic locations in the United States to provide broad characterization of major and trace constituents in the leachate. In addition, speciation of arsenic, selenium, chromium, and mercury in the leachates is being determined. Through 2003, 35 samples were collected at 14 sites representing a variety of CCP types, management approaches, and source coals. Samples have been collected from leachate wells, leachate collection systems, drive-point piezometers, lysimeters, the ash/water interface at impoundments, impoundment outfalls and inlets, and seeps. Additional sampling at 23 sites has been conducted in 2004 or is planned for 2005. First-year results suggest distinct differences in the chemical composition of leachate from landfills and impoundments, and from bituminous and subbituminous coals. Concentrations of most constituents were generally higher in landfill leachate than in impoundment leachate. Sulfate, sodium, aluminum, molybdenum, vanadium, cadmium, mercury and selenium concentrations were higher in leachates for ash from subbituminous source coal. Calcium, boron, lithium, strontium, arsenic, antimony, and nickel were higher for ash from bituminous source coal. These variations will be explored in more detail when additional data from the 2004 and 2005 samples become available.

  11. SELENIUM

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This chapter addresses the nutritional functions of selenium, including the consequences of nutritional selenium deficiency and the role of selenium in the prevention of cancer. These functions are discussed in terms of the absorption and metabolism of dietary selenium, with special focus on the sel...

  12. Biological activity of selenium: Revisited.

    PubMed

    Wrobel, Jagoda K; Power, Ronan; Toborek, Michal

    2016-02-01

    Selenium (Se) is an essential micronutrient that exerts multiple and complex effects on human health. Se is essential for human well-being largely due to its potent antioxidant, anti-inflammatory, and antiviral properties. The physiological functions of Se are carried out by selenoproteins, in which Se is specifically incorporated as the amino acid, selenocysteine. Importantly, both beneficial and toxic effects of Se have been reported suggesting that the mode of action of Se is strictly chemical form and concentration dependent. Additionally, there is a relatively narrow window between Se deficiency and toxicity and growing evidence suggests that Se health effects depend greatly on the baseline level of this micronutrient. Thus, Se supplementation is not an easy task and requires an individualized approach. It is essential that we continue to explore and better characterize Se containing compounds and mechanisms of action, which could be crucial for disease prevention and treatment. PMID:26714931

  13. Water selenium speciation and sediment fractionation in a California flow-through wetland system

    USGS Publications Warehouse

    Gao, S.; Tanii, K.K.; Peters, D.W.; Herbel, M.J.

    2000-01-01

    A flow-through wetland system was established in the Tulare Lake Drainage District (TLDD) in California to determine if selenium (Se) from saline irrigation drainage can be removed prior to impoundment in evaporation basins to reduce potential toxicity to waterbirds. The objective of this research was to evaluate Se speciation, accumulation, and fractionation in the waters and sediments of the newly developed wetland system. The inlet water was dominated by selenate [Se(VI), 92%], with smaller percentages of selenite [Se(IV), 5%] and organic Se [org-Se(-II), 3%]. For the outflow water, the average percentage of Se(VI) was 72% in November 1997 and 59% in February 1999. This change may be due to an increase in either residence time and/or accumulation of organic detrital matter, which may enhance Se(VI) reduction processes. Selenium accumulation, transformation, and incorporation with the solid phase were all intensified in the surface sediment (<20 cm). The highest total Se concentrations in the sediments were found in the top 5 cm and concentrations dramatically decreased with depth. Elemental Se [Se(0)], as extracted by Na2SO3, was the largest fraction (average of 46%) of the total sediment Se, followed by organic matter-associated Se (OM-Se) extracted by NaOH (average of 34%). Soluble, adsorbed, and carbonate-associated Se, as extracted by KCl, K2HPO4 (pH 8.0), and NaOAc (pH 5.0), were about 3, 10, and 3% of the total sediment Se, respectively. After establishing the wetland for 2 yr, significant Se removal from the flowing water was observed. The major sink mechanisms in the sediment are reduction to Se(0) and immobilization into the organic phase.A flow-through wetland system was established in the Tulare Lake Drainage District (TLDD) in California to determine if selenium (Se) from saline irrigation drainage can be removed prior to impoundment in evaporation basins to reduce potential toxicity to waterbirds. The objective of this research was to evaluate Se

  14. Selenium Distribution and Speciation in the Hyperaccumulator Astragalus bisulcatus and Associated Ecological Partners1[W][OA

    PubMed Central

    Valdez Barillas, José R.; Quinn, Colin F.; Freeman, John L.; Lindblom, Stormy D.; Fakra, Sirine C.; Marcus, Matthew A.; Gilligan, Todd M.; Alford, Élan R.; Wangeline, Ami L.; Pilon-Smits, Elizabeth A.H.

    2012-01-01

    The goal of this study was to investigate how plant selenium (Se) hyperaccumulation may affect ecological interactions and whether associated partners may affect Se hyperaccumulation. The Se hyperaccumulator Astragalus bisulcatus was collected in its natural seleniferous habitat, and x-ray fluorescence mapping and x-ray absorption near-edge structure spectroscopy were used to characterize Se distribution and speciation in all organs as well as in encountered microbial symbionts and herbivores. Se was present at high levels (704–4,661 mg kg−1 dry weight) in all organs, mainly as organic C-Se-C compounds (i.e. Se bonded to two carbon atoms, e.g. methylselenocysteine). In nodule, root, and stem, up to 34% of Se was found as elemental Se, which was potentially due to microbial activity. In addition to a nitrogen-fixing symbiont, the plants harbored an endophytic fungus that produced elemental Se. Furthermore, two Se-resistant herbivorous moths were discovered on A. bisulcatus, one of which was parasitized by a wasp. Adult moths, larvae, and wasps all accumulated predominantly C-Se-C compounds. In conclusion, hyperaccumulators live in association with a variety of Se-resistant ecological partners. Among these partners, microbial endosymbionts may affect Se speciation in hyperaccumulators. Hyperaccumulators have been shown earlier to negatively affect Se-sensitive ecological partners while apparently offering a niche for Se-resistant partners. Through their positive and negative effects on different ecological partners, hyperaccumulators may influence species composition and Se cycling in seleniferous ecosystems. PMID:22645068

  15. Chemical speciation and bioavailability of selenium in the rhizosphere of Symphyotrichum eatonii from reclaimed mine soils.

    PubMed

    Oram, Libbie L; Strawn, Daniel G; Möller, Gregory

    2011-02-01

    Knowledge of rhizosphere influences on Se speciation and bioavailability is required to predict Se bioavailability to plants. In the present study, plant-availability of Se to aster (Symphyotrichum eatonii (A. Gray) G.L. Nesom) was compared in rhizosphere soils and nonrhizosphere (bulk) soils collected from a reclaimed mine site in southeastern Idaho, U.S. X-ray spectroscopy was used to characterize the oxidation state and elemental distribution of Se in aster roots, rhizosphere soils, and bulk soils. Percent extractable Se in aster rhizosphere soil was greater than extractable Se in corresponding bulk soils in all samples (n = 4, p = 0.042, 0.051, and 0.052 for three extractions). Selenium oxidation state mapping of 28 regions within the samples and X-ray absorption near edge structure (XANES) spectra from 26 points within the samples indicated that the rhizosphere and bulk soil Se species was predominantly reduced Se(-II,0), while in the aster roots, high concentrations of Se(VI) were present. Results show that within the rhizosphere, enhanced Se bioavailability is occurring via oxidation of reduced soil Se to more soluble Se(VI) species. PMID:21166454

  16. Selenium Speciation and Mobilization in a Controlled Wetland System: Pariette Wetlands, Utah

    NASA Astrophysics Data System (ADS)

    Datta, S.; Crawford, M.; Kelly, L.; Ford, S. K.; Hettiarachchi, G.; van Der Merwe, D.; Tuttle, M. L.; Karna, R.

    2011-12-01

    With headwaters in the heavily irrigated Pleasant Valley, Pariette Wetlands (PW) is an area with high selenium concentrations in both water and sediments. While selenium is an important nutrient, it is toxic at high concentration for many aquatic organisms in their developmental stages, such as reported cases in PW waterfowl. Other PW residents known to be susceptible to selenium poisoning include the locally abundant green sunfish (Lepomis cyanellus). In order to determine the relationship between Se concentrations in the water and sediments, water and wetland sediments were systematically sampled throughout the reach of PW. An observed trend of increased pH from upstream to downstream, and the relative stability of redox potential suggest that the wetlands are a pH controlled system. Total Se and Se speciation in waters were determined by HG-AFS. Water samples from two seasons showed a decreasing trend in total Se from an upstream high of approximately 10ppb to as low as 1ppb downstream. Se concentrations at the end of the irrigation season were approximate 3 times greater than those during the height of irrigation indicating seasonal fluctuations and influence of irrigation practices. As a percent of total Se from upstream to downstream Se (VI) was reduced from approximately 70% to below zero while organically associated Se was inversely proportional to Se (VI). Se (IV) remained relatively steady. Water samples are being analyzed for total anions and cations via IC and ICP-OES. A four acid digestion analysis was employed to determine extractable sediment Se. It ranged from 1.7 mg/L to 0.4 mg/L. Se concentrations in pond sediments were nearly twice that of channel sediments. TOC remained relatively steady for all channel sediments between 0.15 to 0.3 wt% but spiked to as high as 1.75 in the wetland pond sediments. Mineralogy has been determined by μXRF mapping and μXRD on selected hotspots. Semiquantitative speciation within sediments was determined by linear

  17. Speciation of arsenic, selenium, and chromium in wildfire impacted soils and ashes

    USGS Publications Warehouse

    Wolf, Ruth E.; Hoefen, Todd M.; Hageman, Philip L.; Morman, Suzette A.; Plumlee, Geoffrey S.

    2010-01-01

    In 2007-09, California experienced several large wildfires that damaged large areas of forest and destroyed many homes and buildings. The U.S. Geological Survey collected samples from the Harris, Witch, Grass Valley, Ammo, Santiago, Canyon, Jesusita, and Station fires for testing to identify any possible characteristics of the ashes and soils from burned areas that may be of concern for their impact on water quality, human health, and endangered species. The samples were subjected to analysis for bulk chemical composition for 44 elements by inductively coupled plasma mass spectrometry (ICP-MS) after acid digestion and de-ionized water leach tests for pH, alkalinity, conductivity, and anions. Water leach tests generated solutions ranging from pH 10-12, suggesting that ashes can generate caustic alkalinity in contact with rainwater or body fluids (for example, sweat and fluids in the respiratory tract). Samples from burned residential areas in the 2007 fires had elevated levels for several metals, including: As, Pb, Sb, Cu, Zn, and Cr. In some cases, the levels found were above the U.S. Environmental Protection Agency (USEPA) preliminary remediation goals (PRG) for soils. Speciation analyses were conducted on de-ionized water and simulated lung fluid leachates for As(III), As(V), Se(IV), Se(VI), Cr(III), and Cr(VI). All species were determined in the same analytical run using an ion-pairing HPLC-ICP-MS method. For leachates containing high levels of total Cr, the majority of the chromium was present in the hexavalent, Cr(VI), form. Higher total and hexavalent chromium levels were observed for samples collected from burned residential areas. Arsenic was also generally present in the more oxidized, As(V), form. Selenium (IV) and (VI) were present, but typically at levels below 2 ppb for most samples. Stability studies of leachate solutions under different storage conditions were performed and the suitability of different sample preservation methods for speciation

  18. Accelerated aqueous leaching of selenium and arsenic from coal associated rock samples with selenium speciation using ultrasound extraction

    NASA Astrophysics Data System (ADS)

    Pumure, I.; Renton, J. J.; Smart, R. B.

    2009-01-01

    Ultrasound extraction was used to compare the accelerated release rates of selenium and arsenic from three rocks (BT700, BT 571 and BT 60) that are associated with mountaintop mining and valley fill coal mining practiced in southern parts of West Virginia, USA. The concentrations of arsenic released from rocks were found to be three orders of magnitude higher than that of selenium. The accelerated leaching rate constants were ten times higher for arsenic compared to selenium. Se (IV) was found to be stable under ultrasound extraction conditions used whereas As (III) was quickly oxidized to As (V). BT700 was found to have more Se (IV) compared to BT571 while BT60 did not have any significant Se (IV) concentrations. Such compositional and kinetic information becomes important when determining suitable mining waste treatment protocols that have to be undertaken to different types of overburden before it is dumped in valleys.

  19. Selenium levels and Glutathione peroxidase activity in the plasma of patients with type II diabetes mellitus.

    PubMed

    González de Vega, Raquel; Fernández-Sánchez, María Luisa; Fernández, Juan Carlos; Álvarez Menéndez, Francisco Vicente; Sanz-Medel, Alfredo

    2016-09-01

    Selenium, an essential trace element, is involved in the complex system of defense against oxidative stress through selenium-dependent glutathione peroxidases (GPx) and other selenoproteins. Because of its antioxidant properties, selenium or its selenospecies at appropriate levels could hinder oxidative stress and so development of diabetes. In this vein, quantitative speciation of selenium in human plasma samples from healthy and diabetic patients (controlled and non-controlled) was carried out by affinity chromatography (AF) coupled on-line to inductively coupled plasma mass spectrometry (ICP-MS) and isotope dilution analysis (IDA). Similarly, it is well known that patients with diabetes who exhibit poor control of blood glucose show a decreased total antioxidant activity. Thus, we evaluated the enzymatic activity of GPx in diabetic and healthy individuals, using the Paglia and Valentine enzymatic method, observing a significant difference (p<0.05) between the three groups of assayed patients (healthy (n=24): 0.61±0.11U/ml, controlled diabetic (n=38): 0.40±0.12U/ml and non-controlled diabetic patients (n=40): 0.32±0.09U/ml). Our results show that hyperglycemia induces oxidative stress in diabetic patients compared with healthy controls. What is more, glycation of GPx experiments demonstrated that it is the degree of glycation of the selenoenzyme (another species of the Se protein) what actually modulates its eventual activity against ROS in type II diabetes mellitus patients. PMID:27473831

  20. Speciation and Attenuation of Arsenic and Selenium at Coal Combustion By-Product Management Facilities

    SciTech Connect

    K. Ladwig; B. Hensel; D. Wallschlager; L. Lee; I. Murarka

    2005-10-18

    Following completion of contracting activities, sites were identified for the field leachate characterization study. Sampling and Analyses Plans (SAPs) and Site Access Agreements (SAAs) were developed for each site. A total of ten sites were sampled during this reporting period. Among the trace constituents, boron, silicon, and strontium were present in highest concentrations, with median values above 1 mg/L (1,000 {micro}g/L). Work on the first of three sites for the detailed arsenic and selenium adsorption studies began in 2002, prior to completion of the final DOE award. Kd values ranged from 100 to 12,000 L/kg for arsenic (V), 15 to 160 L.kg for As(III), and 5 to 25 L/kg for Se(VI).

  1. On-line pre-reduction of Se(VI) by thiourea for selenium speciation by hydride generation

    NASA Astrophysics Data System (ADS)

    Qiu, Jianhua; Wang, Qiuquan; Ma, Yuning; Yang, Limin; Huang, Benli

    2006-07-01

    In this study, thiourea (TU) was novelly developed as a reduction reagent for on-line pre-reduction of selenium(VI) before conventional hydride generation (HG) by KBH 4/NaOH-HCl. After TU on-line pre-reduction, the HG efficiency of Se(VI) has been greatly improved and because even higher than that of the same amount of Se(IV) obtained in the conventional HG system. The possible pre-reduction mechanism is discussed. The detection limit (DL) of selenate reaches 10 pg mL - 1 when using on-line TU pre-reduction followed by HG atomic fluorescence detection. When TU pre-reduction followed by HG is used as an interface between ion-pair high performance liquid chromatography and atomic fluorescence spectrometry, selenocystine, selenomethionine, selenite and selenate can be measured simultaneously and quantitatively. The DLs of these are 0.06, 0.08, 0.05 and 0.04 ng mL - 1 , respectively, and the relative standard deviations of 9 duplicate runs for all the 4 species are less than 5%. Furthermore, it was successfully applied to Se speciation analysis of cultured garlic samples, and validated by determination of total selenium and selenium species in certified reference material NIST 1946.

  2. Surveying selenium speciation from soil to cell—forms and transformations

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The aim of this review was to present and evaluate the present knowledge on which selenium species are available to the general population in form of food and common supplements and how these species are metabolized in mammals. The overview of the selenium sources is taking a horizontal approach, w...

  3. In Situ Speciation and Distribution of Toxic Selenium in Hydrated Roots of Cowpea1[C][W

    PubMed Central

    Wang, Peng; Menzies, Neal W.; Lombi, Enzo; McKenna, Brigid A.; de Jonge, Martin D.; Paterson, David J.; Howard, Daryl L.; Glover, Chris J.; James, Simon; Kappen, Peter; Johannessen, Bernt; Kopittke, Peter M.

    2013-01-01

    The speciation and spatial distribution of selenium (Se) in hydrated plant tissues is not well understood. Using synchrotron-based x-ray absorption spectroscopy and x-ray fluorescence microscopy (two-dimensional scanning [and associated mathematical model] and computed tomography), the speciation and distribution of toxic Se were examined within hydrated roots of cowpea (Vigna unguiculata) exposed to either 20 µm selenite or selenate. Based upon bulk solution concentrations, selenate was 9-fold more toxic to the roots than selenite, most likely due to increased accumulation of organoselenium (e.g. selenomethionine) in selenate-treated roots. Specifically, uptake of selenate (probably by sulfate transporters) occurred at a much higher rate than for selenite (apparently by both passive diffusion and phosphate transporters), with bulk root tissue Se concentrations approximately 18-fold higher in the selenate treatment. Although the proportion of Se converted to organic forms was higher for selenite (100%) than for selenate (26%), the absolute concentration of organoselenium was actually approximately 5-fold higher for selenate-treated roots. In addition, the longitudinal and radial distribution of Se in roots differed markedly: the highest tissue concentrations were in the endodermis and cortex approximately 4 mm or more behind the apex when exposed to selenate but in the meristem (approximately 1 mm from the apex) when exposed to selenite. The examination of the distribution and speciation of Se in hydrated roots provides valuable data in understanding Se uptake, transport, and toxicity. PMID:23835408

  4. Do selenium hyperaccumulators affect selenium speciation in neighboring plants and soil? An X-Ray Microprobe Analysis.

    PubMed

    El Mehdawi, Ali F; Lindblom, Stormy D; Cappa, Jennifer J; Fakra, Sirine C; Pilon-Smits, Elizabeth A H

    2015-01-01

    Neighbors of Se hyperaccumulators Stanleya pinnata and Astragalus bisulcatus were found earlier to have elevated Se levels. Here we investigate whether Se hyperaccumulators affect Se localization and speciation in surrounding soil and neighboring plants. X-ray fluorescence mapping and X-ray absorption near-edge structure spectroscopy were used to analyze Se localization and speciation in leaves of Artemisia ludoviciana, Symphyotrichum ericoides and Chenopodium album growing next to Se hyperaccumulators or non-accumulators at a seleniferous site. Regardless of neighbors, A. ludoviciana, S. ericoides and C. album accumulated predominantly (73-92%) reduced selenocompounds with XANES spectra similar to the C-Se-C compounds selenomethionine and methyl-selenocysteine. Preliminary data indicate that the largest Se fraction (65-75%), both in soil next to hyperaccumulator S. pinnata and next to nonaccumulator species was reduced Se with spectra similar to C-Se-C standards. These same C-Se-C forms are found in hyperaccumulators. Thus, hyperaccumulator litter may be a source of organic soil Se, but soil microorganisms may also contribute. These findings are relevant for phytoremediation and biofortification since organic Se is more readily accumulated by plants, and more effective for dietary Se supplementation. PMID:26030363

  5. 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. PMID:26846236

  6. SELENIUM CONCENTRATIONS AND GLULATHIONE PEROXIDASE ACTIVITIES IN A POPULATION EXPOSED TO SELENIUM VIA DRINKING WATER

    EPA Science Inventory

    Selenium concentrations in blood, urine, hair, and tap water were determined in samples obtained from individuals exposed to varying amounts of the element via water from home wells. Glutathione peroxidase activities were also determined on the blood samples. Correlations of bloo...

  7. Microscopically focused synchrotron X-ray investigation of selenium speciation in soils developing on reclaimed mine lands.

    PubMed

    Ryser, Amy L; Strawn, Daniel G; Marcus, Matthew A; Fakra, Sirine; Johnson-Maynard, Jodi L; Möller, Gregory

    2006-01-15

    Chemical speciation determines Se solubility and therefore its bioavailability and potential for transport in the environment. In this study we investigated the speciation of Se in soil developed on reclaimed mine sites in the U.S. Western Phosphate Resource Area (WPRA) using micro-X-ray absorption near-edge structure (micro-XANES) spectroscopy and micro-X-ray fluorescence (micro-XRF) mapping. Selenium was nonuniformly distributed in the soils and positively correlated with Fe, Mn, Cu, Zn, and Ni. Sixteen points of interest (POI) from three soil samples were analyzed with micro-XANES spectroscopy. The XANES data indicated that Se is present in the soils in at least three oxidation states, Se(-II, 0), Se(IV), and Se(VI). Selenides or elemental Se dominated 7 of the 16 POI. Selenate was the dominant species at only one of the POI. The remaining eight POI were composed of both Se(IV) and Se(VI), with minor Se(-II, 0) contributions. The results of this research suggest that the reduced Se species in the soil parent material are oxidizing to Se(VI), one of the more mobile species of Se in the environment. This information can be used to better predict and manage Se availability in soils. PMID:16468390

  8. Speciation of inorganic selenium in environmental samples after suspended dispersive solid phase microextraction combined with inductively coupled plasma spectrometric determination.

    PubMed

    Nyaba, Luthando; Matong, Joseph M; Dimpe, K Mogolodi; Nomngongo, Philiswa N

    2016-10-01

    A rapid and effective suspended dispersive solid phase microextraction (SDSPME) was developed for the speciation of inorganic selenium using alumina nanoparticles functionalized with Aliquat-336. The target analytes were preconcentrated and determined by inductively coupled plasma optical emission spectrometry. Alumina nanoparticles were characterized using XRD, BET, SEM and EDX while the functionalized nano-Al2O3 was characterized by FTIR. The effect of pH of the solution on speciation Se in water samples was optimized separately. It was observed that when the pH values of sample solution ranged from 2.0 to 7.0, successful separation of inorganic Se species was achieved. The percentage recoveries for Se (IV) and Se (VI) were >90% and 5%, respectively. The two-level fractional factorial design was used to optimize experimental parameters affecting the preconcentration system. Under optimal conditions, the enrichment factor (EF), limit of detection (LOD) and limit of quantification for Se (IV) were found to be 850, 1.4ngL(-1,) and 4.6ngL(-1), respectively. Furthermore, intra-day and inter-day precisions expressed in terms of relative standard deviation (RSD) were found to be 1.9% and 3.3%, respectively. The effect of coexisting ions on the recovery of Se (IV) was investigated. The accuracy of the developed method was checked by analysis of standard reference material (NIST SRM 1643e). The optimized method was applied for the determination of targets in surface water samples. PMID:27474295

  9. Magnetic effervescent tablet-assisted ionic liquid dispersive liquid-liquid microextraction of selenium for speciation in foods and beverages.

    PubMed

    Wang, Xiaojun; Wu, Long; Cao, Jiaqi; Hong, Xincheng; Ye, Rui; Chen, Weiji; Yuan, Ting

    2016-07-01

    A novel, simple and rapid method based on magnetic effervescent tablet-assisted ionic liquid dispersive liquid-liquid microextraction (MEA-IL-DLLME) followed by graphite furnace atomic absorption spectrometry (GFAAS) determination was established for the speciation of selenium in various food and beverage samples. In the procedure, a special magnetic effervescent tablet containing CO2 sources (sodium carbonate and sodium dihydrogenphosphate), ionic liquids and Fe3O4 magnetic nanoparticles (MNPs) was used to combine extractant dispersion and magnetic recovery procedures into a single step. The parameters influencing the microextraction efficiency, such as pH of the sample solution, volume of ionic liquid, amount of MNPs, concentration of the chelating agent, salt effect and matrix effect were investigated and optimised. Under the optimised conditions, the limits of detection (LODs) for Se(IV) were 0.021 μg l(-)(1) and the linear dynamic range was 0.05-5.0 μg l(-)(1). The relative standard deviation for seven replicate measurements of 1.0 μg l(-)(1) of Se(IV) was 2.9%. The accuracy of the developed method was evaluated by analysis of the standard reference materials (GBW10016 tea, GBW10017 milk powder, GBW10043 Liaoning rice, GBW10046 Henan wheat, GBW10048 celery). The proposed method was successfully applied to food and beverage samples including black tea, milk powder, mushroom, soybean, bamboo shoots, energy drink, bottled water, carbonated drink and mineral water for the speciation of Se(IV) and Se(VI) with satisfactory relative recoveries (92.0-108.1%). PMID:27181611

  10. Selenium distribution and speciation in plant parts of wheat (Triticum aestivum) and Indian mustard (Brassica juncea) from a seleniferous area of Punjab, India.

    PubMed

    Eiche, E; Bardelli, F; Nothstein, A K; Charlet, L; Göttlicher, J; Steininger, R; Dhillon, K S; Sadana, U S

    2015-02-01

    The concentration, distribution, and speciation of selenium in different parts of wheat and Indian mustard, grown in a seleniferous area in Punjab, were investigated using synchrotron based (XAS) and classical acid digestion and extraction methods. The analyses revealed a high Se enrichment in all investigated plant parts, with Se levels in the range of 133-931 mg/kg (dry weight, dw). Such high Se enrichment is mainly due to the considerable amounts of easily available Se detected in the soil, which are renewed on a yearly basis to some extent via irrigation. Speciation analysis in soil and plants indicated selenate and organic Se as major Se species taken up by plants, with a minor presence of selenite. The analyses also revealed that the highest Se enrichment occurs in the upper plant parts, in agreement with the high uptake rate and mobility of selenate within plants. In both wheat and mustard, highest Se enrichments were found in leaves (387 mg/kg·dw in wheat and 931 mg/kg·dw in mustard). Organic species (dimethylselenide and methylselenocysteine) were found in different parts of both plants, indicating that an active detoxification response to the high Se uptake is taking place through methylation and/or volatilization. The high proportion of selenate in wheat and mustard leaves (47% and 70%, respectively) is the result of the inability of the plant metabolism to completely transform selenate to non-toxic organic forms, if oversupplied. Methylselenocysteine, a common Se species in accumulating plants, was detected in wheat, suggesting that, in the presence of high Se concentration, this plant develops similar response mechanisms to accumulator plants. PMID:25461096

  11. Selenium Accumulation, Distribution, and Speciation in Spineless Prickly Pear Cactus: A Drought- and Salt-Tolerant, Selenium-Enriched Nutraceutical Fruit Crop for Biofortified Foods

    SciTech Connect

    Banuelos, Gary S.; Fakra, Sirine C.; Walse, Spencer S.; Marcus, Matthew A.; Yang, Soo In; Pickering, Ingrid J.; Pilon-Smits, Elizabeth A.H.; Freeman, John L.

    2011-07-01

    The organ-specific accumulation, spatial distribution, and chemical speciation of selenium (Se) were previously unknown for any species of cactus. We investigated Se in Opuntia ficus-indica using inductively coupled plasma mass spectrometry, microfocused x-ray fluorescence elemental and chemical mapping ({micro}XRF), Se K-edge x-ray absorption near-edge structure (XANES) spectroscopy, and liquid chromatography-mass spectrometry (LC-MS). {micro}XRF showed Se concentrated inside small conic, vestigial leaves (cladode tips), the cladode vasculature, and the seed embryos. Se K-edge XANES demonstrated that approximately 96% of total Se in cladode, fruit juice, fruit pulp, and seed is carbon-Se-carbon (C-Se-C). Micro and bulk XANES analysis showed that cladode tips contained both selenate and C-Se-C forms. Inductively coupled plasma mass spectrometry quantification of Se in high-performance liquid chromatography fractions followed by LC-MS structural identification showed selenocystathionine-to-selenomethionine (SeMet) ratios of 75:25, 71:29, and 32:68, respectively in cladode, fruit, and seed. Enzymatic digestions and subsequent analysis confirmed that Se was mainly present in a 'free' nonproteinaceous form inside cladode and fruit, while in the seed, Se was incorporated into proteins associated with lipids. {micro}XRF chemical mapping illuminated the specific location of Se reduction and assimilation from selenate accumulated in the cladode tips into the two LC-MS-identified C-Se-C forms before they were transported into the cladode mesophyll. We conclude that Opuntia is a secondary Se-accumulating plant whose fruit and cladode contain mostly free selenocystathionine and SeMet, while seeds contain mainly SeMet in protein. When eaten, the organic Se forms in Opuntia fruit, cladode, and seed may improve health, increase Se mineral nutrition, and help prevent multiple human cancers.

  12. Selenium Accumulation, Distribution, and Speciation in Spineless Prickly Pear Cactus: A Drought- and Salt-Tolerant, Selenium-Enriched Nutraceutical Fruit Crop for Biofortified Foods1[OA

    PubMed Central

    Bañuelos, Gary S.; Fakra, Sirine C.; Walse, Spencer S.; Marcus, Matthew A.; Yang, Soo In; Pickering, Ingrid J.; Pilon-Smits, Elizabeth A.H.; Freeman, John L.

    2011-01-01

    The organ-specific accumulation, spatial distribution, and chemical speciation of selenium (Se) were previously unknown for any species of cactus. We investigated Se in Opuntia ficus-indica using inductively coupled plasma mass spectrometry, microfocused x-ray fluorescence elemental and chemical mapping (μXRF), Se K-edge x-ray absorption near-edge structure (XANES) spectroscopy, and liquid chromatography-mass spectrometry (LC-MS). μXRF showed Se concentrated inside small conic, vestigial leaves (cladode tips), the cladode vasculature, and the seed embryos. Se K-edge XANES demonstrated that approximately 96% of total Se in cladode, fruit juice, fruit pulp, and seed is carbon-Se-carbon (C-Se-C). Micro and bulk XANES analysis showed that cladode tips contained both selenate and C-Se-C forms. Inductively coupled plasma mass spectrometry quantification of Se in high-performance liquid chromatography fractions followed by LC-MS structural identification showed selenocystathionine-to-selenomethionine (SeMet) ratios of 75:25, 71:29, and 32:68, respectively in cladode, fruit, and seed. Enzymatic digestions and subsequent analysis confirmed that Se was mainly present in a “free” nonproteinaceous form inside cladode and fruit, while in the seed, Se was incorporated into proteins associated with lipids. μXRF chemical mapping illuminated the specific location of Se reduction and assimilation from selenate accumulated in the cladode tips into the two LC-MS-identified C-Se-C forms before they were transported into the cladode mesophyll. We conclude that Opuntia is a secondary Se-accumulating plant whose fruit and cladode contain mostly free selenocystathionine and SeMet, while seeds contain mainly SeMet in protein. When eaten, the organic Se forms in Opuntia fruit, cladode, and seed may improve health, increase Se mineral nutrition, and help prevent multiple human cancers. PMID:21059825

  13. Methods for the speciation and determination of arsenic and selenium in coal combustion products

    SciTech Connect

    Schabron, J.F.; Hart, B.K.; Niss, N.D.; Brown, T.H.

    1991-11-01

    Methods of sample preparation for the determination of total selenium, and selenite, selenate, arsenite, and arsenate in coal fly ash materials were evaluated. The measurement methods use atomic spectroscopy for the determination of total concentrations and ion chromatography (IC) for the determination of individual ionic species. Sample preparation procedures which minimize the loss or alteration of the species of interest was explored and defined. The utility of the sample preparation methods can be sample dependent, so caution is advised in their use. IC conditions were established for the determination in extract solutions of selenite, selenate, arsenite, and arsenate with minimal interference from common anions.

  14. SELENIUM TREATMENT/REMOVAL ALTERNATIVES DEMONSTRATION PROJECT - MINE WASTE TECHNOLOGY PROGRAM ACTIVITY III, PROJECT 20

    EPA Science Inventory

    This document is the final report for EPA's Mine WAste Technology Program (MWTP) Activity III, Project 20--Selenium Treatment/Removal Alternatives Demonstration project. Selenium contamination originates from many sources including mining operations, mineral processing, abandoned...

  15. 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.

  16. Selenium bond decreases ON resistance of light-activated switch

    NASA Technical Reports Server (NTRS)

    1965-01-01

    Vitrified amorphous selenium bond decreases the ON resistance of a gallium arsenide-silicon light-activated, low-level switch. The switch is used under a pulse condition to prolong switch life and minimize errors due to heating, devitrification, and overdrawing.

  17. Selenium Speciation in Biofilms from Granular Sludge Bed Reactors Used for Wastewater Treatment

    SciTech Connect

    van Hullenbusch, Eric; Farges, Francois; Lenz, Markus; Lens, Piet; Brown, Gordon E., Jr.; /Stanford U., Geo. Environ. Sci. /SLAC, SSRL

    2006-12-13

    Se K-edge XAFS spectra were collected for various model compounds of Se as well as for 3 biofilm samples from bioreactors used for Se-contaminated wastewater treatment. In the biofilm samples, Se is dominantly as Se(0) despite Se K-edge XANES spectroscopy cannot easily distinguish between elemental Se and Se(-I)-bearing selenides. EXAFS spectra indicate that Se is located within aperiodic domains, markedly different to these known in monoclinic red selenium. However, Se can well occur within nanodivided domains related to monoclinic red Se, as this form was optically observed at the rim of some sludges. Aqueous selenate is then efficiently bioreduced, under sulfate reducing and methanogenic conditions.

  18. Selenium Speciation in Biofilms from Granular Sludge Bed Reactors Used for Wastewater Treatment

    SciTech Connect

    Hullenbusch, Eric van; Farges, Francois; Lenz, Markus; Lens, Piet; Brown, Gordon E. Jr.

    2007-02-02

    Se K-edge XAFS spectra were collected for various model compounds of Se as well as for 3 biofilm samples from bioreactors used for Se-contaminated wastewater treatment. In the biofilm samples, Se is dominantly as Se(0) despite Se K-edge XANES spectroscopy cannot easily distinguish between elemental Se and Se(-I)-bearing selenides. EXAFS spectra indicate that Se is located within aperiodic domains, markedly different to these known in monoclinc red selenium. However, Se can well occur within nanodivided domains related to monoclinic red Se, as this form was optically observed at the rim of some sludges. Aqueous selenate is then efficiently bioreduced, under sulfate reducing and methanogenic conditions.

  19. Selenium Speciation in Biofilms from Granular Sludge Bed Reactors Used for Wastewater Treatment

    NASA Astrophysics Data System (ADS)

    van Hullenbusch, Eric; Farges, François; Lenz, Markus; Lens, Piet; Brown, Gordon E.

    2007-02-01

    Se K-edge XAFS spectra were collected for various model compounds of Se as well as for 3 biofilm samples from bioreactors used for Se-contaminated wastewater treatment. In the biofilm samples, Se is dominantly as Se(0) despite Se K-edge XANES spectroscopy cannot easily distinguish between elemental Se and Se(-I)-bearing selenides. EXAFS spectra indicate that Se is located within aperiodic domains, markedly different to these known in monoclinc red selenium. However, Se can well occur within nanodivided domains related to monoclinic red Se, as this form was optically observed at the rim of some sludges. Aqueous selenate is then efficiently bioreduced, under sulfate reducing and methanogenic conditions.

  20. Ultrasound-assisted ionic liquid dispersive liquid-liquid microextraction combined with graphite furnace atomic absorption spectrometric for selenium speciation in foods and beverages.

    PubMed

    Tuzen, Mustafa; Pekiner, Ozlem Zeynep

    2015-12-01

    A rapid and environmentally friendly ultrasound assisted ionic liquid dispersive liquid liquid microextraction (USA-IL-DLLME) was developed for the speciation of inorganic selenium in beverages and total selenium in food samples by using graphite furnace atomic absorption spectrometry. Some analytical parameters including pH, amount of complexing agent, extraction time, volume of ionic liquid, sample volume, etc. were optimized. Matrix effects were also investigated. Enhancement factor (EF) and limit of detection (LOD) for Se(IV) were found to be 150 and 12 ng L(-1), respectively. The relative standard deviation (RSD) was found 4.2%. The accuracy of the method was confirmed with analysis of LGC 6010 Hard drinking water and NIST SRM 1573a Tomato leaves standard reference materials. Optimized method was applied to ice tea, soda and mineral water for the speciation of Se(IV) and Se(VI) and some food samples including beer, cow's milk, red wine, mixed fruit juice, date, apple, orange, grapefruit, egg and honey for the determination of total selenium. PMID:26041239

  1. Simultaneous Speciation of Arsenic, Selenium, and Chromium by HPLC-ICP-MS

    USGS Publications Warehouse

    Wolf, Ruth E.; Morman, Suzette A.; Morrison, Jean M.; Lamothe, Paul J.

    2008-01-01

    An adaptation of an analytical method developed for chromium speciation has been utilized for the simultaneous determination of As(III), As(V), Se(IV), Se(VI), Cr(III), and Cr(VI) species using high performance liquid chromatography (HPLC) separation with ICP-MS detection. Reduction of interferences for the determination of As, Se, and Cr by ICP-MS is a major consideration for this method. Toward this end, a Dynamic Reaction Cell (DRC) ICP-MS system was used to detect the species eluted from the chromatographic column. A variety of reaction cell gases and conditions may be utilized, and the advantages and limitations of the gases tested to date will be presented and discussed. The separation and detection of the As, Se, and Cr species of interest can be achieved using the same chromatographic conditions in less than 2 minutes by complexing the Cr(III) with EDTA prior to injection on the HPLC column. Practical aspects of simultaneous speciation analysis will be presented and discussed, including issues with HPLC sample vial contamination, standard and sample contamination, species stability, and considerations regarding sample collection and preservation methods. The results of testing to determine the method's robustness to common concomitant element and anion effects will also be discussed. Finally, results will be presented using the method for the analysis of a variety of environmental and geological samples including waters, soil leachates and simulated bio-fluid leachates.

  2. Simultaneous speciation of arsenic, selenium, and chromium: Species stability, sample preservation, and analysis of ash and soil leachates

    USGS Publications Warehouse

    Wolf, R.E.; Morman, S.A.; Hageman, P.L.; Hoefen, T.M.; Plumlee, G.S.

    2011-01-01

    An analytical method using high-performance liquid chromatography separation with inductively coupled plasma mass spectrometry (ICP-MS) detection previously developed for the determination of Cr(III) and Cr(VI) has been adapted to allow the determination of As(III), As(V), Se(IV), Se(VI), Cr(III), and Cr(VI) under the same chromatographic conditions. Using this method, all six inorganic species can be determined in less than 3 min. A dynamic reaction cell (DRC)-ICP-MS system was used to detect the species eluted from the chromatographic column in order to reduce interferences. A variety of reaction cell gases and conditions may be utilized with the DRC-ICP-MS, and final selection of conditions is determined by data quality objectives. Results indicated all starting standards, reagents, and sample vials should be thoroughly tested for contamination. Tests on species stability indicated that refrigeration at 10 ??C was preferential to freezing for most species, particularly when all species were present, and that sample solutions and extracts should be analyzed as soon as possible to eliminate species instability and interconversion effects. A variety of environmental and geological samples, including waters and deionized water [leachates] and simulated biological leachates from soils and wildfire ashes have been analyzed using this method. Analytical spikes performed on each sample were used to evaluate data quality. Speciation analyses were conducted on deionized water leachates and simulated lung fluid leachates of ash and soils impacted by wildfires. These results show that, for leachates containing high levels of total Cr, the majority of the chromium was present in the hexavalent Cr(VI) form. In general, total and hexavalent chromium levels for samples taken from burned residential areas were higher than those obtained from non-residential forested areas. Arsenic, when found, was generally in the more oxidized As(V) form. Selenium (IV) and (VI) were present

  3. Simultaneous speciation of arsenic, selenium, and chromium: species, stability, sample preservation, and analysis of ash and soil leachates

    USGS Publications Warehouse

    Wolf, Ruth E.; Morman, Suzette A.; Hageman, Philip L.; Hoefen, Todd M.; Plumlee, Geoffrey S.

    2011-01-01

    An analytical method using high-performance liquid chromatography separation with inductively coupled plasma mass spectrometry (ICP-MS) detection previously developed for the determination of Cr(III) and Cr(VI) has been adapted to allow the determination of As(III), As(V), Se(IV), Se(VI), Cr(III), and Cr(VI) under the same chromatographic conditions. Using this method, all six inorganic species can be determined in less than 3 min. A dynamic reaction cell (DRC)-ICP-MS system was used to detect the species eluted from the chromatographic column in order to reduce interferences. A variety of reaction cell gases and conditions may be utilized with the DRC-ICP-MS, and final selection of conditions is determined by data quality objectives. Results indicated all starting standards, reagents, and sample vials should be thoroughly tested for contamination. Tests on species stability indicated that refrigeration at 10° C was preferential to freezing for most species, particularly when all species were present, and that sample solutions and extracts should be analyzed as soon as possible to eliminate species instability and interconversion effects. A variety of environmental and geological samples, including waters and deionized water [leachates] and simulated biological leachates from soils and wildfire ashes have been analyzed using this method. Analytical spikes performed on each sample were used to evaluate data quality. Speciation analyses were conducted on deionized water leachates and simulated lung fluid leachates of ash and soils impacted by wildfires. These results show that, for leachates containing high levels of total Cr, the majority of the chromium was present in the hexavalent Cr(VI) form. In general, total and hexavalent chromium levels for samples taken from burned residential areas were higher than those obtained from non-residential forested areas. Arsenic, when found, was generally in the more oxidized As(V) form. Selenium (IV) and (VI) were present

  4. Effect of Sulfate on Selenium Uptake And Chemical Speciation in Convolvulus Arvensis L

    SciTech Connect

    Cruz-Jimenez, G.; Peralta-Video, J.R.; Rosa, G.de la; Meitzner, G.; Parson, J.G.; Gardea-Torresdey, J.L.

    2007-08-08

    Hydroponic experiments were performed to study several aspects of Se uptake by C. arvensis plants. Ten day old seedlings were exposed for eight days to different combinations of selenate (SeO{sub 4}{sup 2-}), sulfate (SO{sub 4}{sup 2-}), and selenite (SeO{sub 3}{sup 2-}). The results showed that in C. arvensis, SO{sub 4}{sup 2-} had a negative effect (P < 0.05) on SeO{sub 4}{sup 2-} uptake. However, a positive interaction produced a significant increase in SO{sub 4}{sup 2-} uptake when SeO{sub 4}{sup 2-} was at high concentration in the media. X-ray absorption spectroscopy studies showed that C. arvensis plants converted more than 70% of the supplied SeO{sub 3}{sup 2-} into organoselenium compounds. However, only approximately 50% of the supplied SeO{sub 4}{sup 2-} was converted into organoselenium species while the residual 50% remained in the inorganic form. Analysis using LC-XANES fittings confirmed that the S metabolic pathway was affected by the presence of Se. The main Se compounds that resembled those Se species identified in C. arvensis were Se-cystine, Se-cysteine, SeO{sub 3}{sup 2-}, and SeO{sub 4}{sup 2-}, whereas for S the main compounds were cysteine, cystine, oxidized glutathione, reduced glutathione, and SO{sub 4}{sup 2-}. The results of these studies indicated that C. arvensis could be considered as a possible option for the restoration of soil moderately contaminated with selenium even in the presence of sulfate.

  5. Selenium speciation in Lower Cambrian Se-enriched strata in South China and its geological implications

    NASA Astrophysics Data System (ADS)

    Fan, Haifeng; Wen, Hanjie; Hu, Ruizhong; Zhao, Hui

    2011-12-01

    To understand the impact of Selenium (Se) into the biogeochemical cycle and implications for palaeo-redox environment, a sequential extraction method was utilized for samples including black shales, cherts, a Ni-Mo-Se sulfide layer, K-bentonite and phosphorite from Lower Cambrian Se-enriched strata in southern China. Seven species (water-soluble, phosphate exchangeable, base-soluble, acetic acid-soluble, sulfide/selenide associated, residual Se) and different oxidation states (selenate Se(VI), selenite Se(IV), organic Se, Se (0) and mineral Se(-II)) were determinated in this study. We found that the Ni-Mo-Se sulfide layer contained a significantly greater amount of Se(-II) associated with sulfides/selenides than those in host black shales and cherts. Furthermore, a positive correlation between the degree of sulfidation of iron (DOS) and the percentage of the sulfide/selenide-associated Se(-II) was observed for samples, which suggests the proportion of sulfide/selenide-associated Se(-II) could serve as a proxy for palaeo-redox conditions. In addition, the higher percentage of Se(IV) in K-bentonite and phosphorite was found and possibly attributed to the adsorption of Se by clay minerals, iron hydroxide surfaces and organic particles. Based on the negative correlations between the percentage of Se(IV) and that of Se(-II) in samples, we propose that the K-bentonite has been altered under the acid oxic conditions, and the most of black shale (and cherts) and the Ni-Mo-Se sulfide layer formed under the anoxic and euxinic environments, respectively. Concerning Se accumulation in the Ni-Mo-Se sulfide layer, the major mechanism can be described by (1) biotic and abiotic adsorption and further dissimilatory reduction from oxidized Se(VI) and Se(IV) to Se(-II), through elemental Se, (2) contribution of hydrothermal fluid with mineral Se(-II).

  6. Selenium speciation in paired serum and cerebrospinal fluid samples of sheep.

    PubMed

    Humann-Ziehank, Esther; Ganter, Martin; Michalke, Bernhard

    2016-01-01

    This study was performed to characterise selenium (Se) and Se species in cerebrospinal fluid (CSF) of sheep and its relation to the respective Se concentrations in serum. Paired samples from 10 adult sheep were used for the study. Five sheep were fed a diet with a marginal Se concentration of <0.05mg Se/kg diet dry weight (dw, Se(-)), and five animals were fed the same diet supplemented with sodium selenite revealing a concentration of 0.2mg Se/kg diet dw (Se(+)). The feeding strategy was conducted for two years; The results on metabolic effects were published previously. At the end of the feeding period, paired samples of serum and CSF were collected and analysed using ion exchange chromatography inductively coupled plasma-dynamic reaction cell-mass spectrometry (IEC-ICP-DRC-MS) technique for total Se concentration and concentrations of Se species. Albumin concentrations were analysed additionally. The feeding strategy caused significant differences (p<0.01) in serum Se concentrations with 33.1±5.11μg Se/l in the Se(-) group and 96.5±18.3μg Se/l in the Se(+) group, respectively. The corresponding total Se concentrations in CSF were 4.38±1.02μg Se/l and 6.13±1.64μg Se/l in the Se(-) and the Se(+) group, respectively, missing statistical significance (p=0.077). IEC-ICP-DRC-MS technique was able to differentiate the Se species selenoprotein P-bound Se (SePP), selenomethionine, glutathione peroxidase-bound Se (Se-GPx), selenocystine, thioredoxin reductase-bound Se, ovine serum albumin-bound Se (Se-OSA), SeIV and SeVI in ovine serum and CSF. Quantitatively, SePP is the main selenoprotein in ovine serum followed by Se-GPx. The CSF/blood ratio of albumin (QAlbumin) reflected a physiological function of the blood-CSF barrier in all sheep. QSe-species were higher than QAlbumin both feeding groups, supporting the hypothesis of local production of Se species in the brain. Significant positive regression lines for CSF vs. serum were found for albumin and Se-OSA only

  7. Antioxidant and antiproliferative activities in different maturation stages of broccoli (Brassica oleracea Italica) biofortified with selenium.

    PubMed

    Bachiega, Patricia; Salgado, Jocelem Mastrodi; de Carvalho, João Ernesto; Ruiz, Ana Lúcia T G; Schwarz, Kélin; Tezotto, Tiago; Morzelle, Maressa Caldeira

    2016-01-01

    In this work, three different broccoli maturity stages subjected to biofortification with selenium were evaluated for antioxidant and antiproliferative activities. Antioxidant trials have shown that the maturation stages biofortified with selenium had significantly higher amounts of phenolic compounds and antioxidant activity, especially seedlings. Although non-polar extracts of all samples show antiproliferative activity, the extract of broccoli seedlings biofortified with selenium stood out, presenting cytocidal activity for a glioma line (U251, GI50 28.5 mg L(-1)). PMID:26213037

  8. Effect of chemical form of selenium on tissue glutathione peroxidase activity in developing rats

    NASA Technical Reports Server (NTRS)

    Lane, Helen W.; Strength, Ralph; Johnson, Janet; White, Marguerite T.

    1991-01-01

    The hypothesis that the stage of development of rats may affect the availability of various forms of selenium for the activity of glutathione peroxidase (GSHPx) in the rat was experimentally investigated. One experiment evaluated the availability of selenium as selenite or selenomethionine for GSPHx activity during three developmental states in rats: fetus and 7-day old and 14-day old nursing pups. In all tissues studied, GSHPx activity was highest in the 14-day-old pups whose dams were in the selenomethionine group. Rat pups given intraperitoneal selenite had higher liver and kidney GSHPx activity than pups given the same amount of selenium as intraperitoneal selenomethionine. In a second experiment, all dams were fed the same basal diet and pups were weaned to diets containing one of two levels of selenium and one of three forms of selenium (selenite, selenomethionine, or selenocystine). The results also supported the hypothesis these dietary forms of selenium are differentially available for GSHPx activity.

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

    USGS Publications Warehouse

    Franson, J.C.; Hoffman, D.J.; Schmutz, J.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 feathera??molting 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.

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

    USGS Publications Warehouse

    Franson, J.C.; Hoffman, D.J.; Schmutz, J.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.

  11. Selenium accumulation, distribution and speciation in spineless prickly pear cactus: a salt, boron, and drought tolerant, selenium-enriched nutraceutical fruit crop.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Prickly pear cactus (Opuntia) may be an alternative crop to grow in drainage-impacted regions of the westside of California, where high levels of salinity, selenium (Se), and boron (B) are present. Preliminary trials have demonstrated that Opuntia can tolerate the adverse soil conditions, while accu...

  12. Redox-Active Selenium Compounds—From Toxicity and Cell Death to Cancer Treatment

    PubMed Central

    Misra, Sougat; Boylan, Mallory; Selvam, Arun; Spallholz, Julian E.; Björnstedt, Mikael

    2015-01-01

    Selenium is generally known as an antioxidant due to its presence in selenoproteins as selenocysteine, but it is also toxic. The toxic effects of selenium are, however, strictly concentration and chemical species dependent. One class of selenium compounds is a potent inhibitor of cell growth with remarkable tumor specificity. These redox active compounds are pro-oxidative and highly cytotoxic to tumor cells and are promising candidates to be used in chemotherapy against cancer. Herein we elaborate upon the major forms of dietary selenium compounds, their metabolic pathways, and their antioxidant and pro-oxidant potentials with emphasis on cytotoxic mechanisms. Relative cytotoxicity of inorganic selenite and organic selenocystine compounds to different cancer cells are presented as evidence to our perspective. Furthermore, new novel classes of selenium compounds specifically designed to target tumor cells are presented and the potential of selenium in modern oncology is extensively discussed. PMID:25984742

  13. Effects of commercial selenium products on glutathione peroxidase activity and semen quality in stud boars

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The aim of this study was to determine how dietary supplementation of inorganic and organic selenium affects selenium concentration and glutathione peroxidase activity in blood and sperm of sexually mature stud boars. Twenty-four boars of the Large White, Landrace, Pietrain, and Duroc breeds of opt...

  14. Speciation analysis of selenium in plankton, Brazil nut and human urine samples by HPLC-ICP-MS.

    PubMed

    da Silva, Elidiane Gomes; Mataveli, Lidiane Raquel Verola; Arruda, Marco Aurélio Zezzi

    2013-06-15

    The HPLC (anion exchange)-ICP-MS technique was used for the identification (based on retention time of standards) and determination of four selenium species (selenite, selenate, selenomethionine and selenocystine) in plankton (BCR-414), Brazil nuts and urine samples. A recovery of 91% was attained for certified reference materials (BCR-414). Se(IV) was the predominant species in plankton, with the highest selenium concentration in the extract. The Brazil nuts showed only the organic species selenomethionine and selenocystine after water extraction, but after simulated gastrointestinal digestion, only selenomethionine was found as bioaccessible, corresponding to 74% of the total selenium (54.8±4.6 μg g(-1)). Analyses of the urine samples suggested the presence of selenocystine, and significant differences were observed between samples from men and women in terms of the concentration of this species after consumption of Brazil nuts (1 nut per day during 15 days). PMID:23618175

  15. 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

  16. Nutritional aspects of selenium

    SciTech Connect

    Choe, M.

    1987-01-01

    The overall objective of this project was to investigate the effect of protein and/or dietary fiber supplementation on selenium absorption and metabolism. These relationships might be of importance in determining either minimum selenium nutritional requirements or levels of intake at which this mineral becomes toxic. Three studies compose the project. The first study involved the controlled feeding of fifteen young adults mice. Subjects were fed a laboratory-controlled diet with and without supplements of selenium or selenium plus guar gum. Selenium supplementation resulted in increased selenium excretion in urine and feces. Supplementation of guar gum, as a dietary fiber, tended to increase fecal selenium excretion and to decrease selenium balance and glutathione peroxidase (GSH-Px) activity regardless of dietary selenium levels. In study II, seventy two weanling mice were fed varied levels of dietary selenium and protein. Numerically, urinary selenium excretion increased and fecal selenium excretion and selenium balance decreased with increased dietary protein level within the same level of dietary selenium; however, selenium absorption rate tended to decrease with increased dietary protein level. Whole blood and brain tissue glutathione peroxidase activities were higher in animals fed moderate protein level than those fed the other two protein levels. In study III, a survey was conducted to investigate the correlation between dietary fiber or protein intake and urinary selenium excretion. There was a negative correlation between dietary fiber and urinary selenium excretion levels while dietary protein and urinary selenium excretion were positively correlated.

  17. Selenium fertilization on lentil (Lens culinaris Medikus) grain yield, seed selenium concentration, and antioxidant activity.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Selenium (Se) is an essential element for mammals but has not been considered as an essential element for higher plants. Lentil (Lens culinaris Medik.) is a cool season food legume rich in protein and a range of micronutrients including minerals (iron and zinc), folates, and carotenoids. The objecti...

  18. SPECIATION OF SELENIUM AND ARSENIC COMPOUNDS BY CAPILLARY ELECTROPHORESIS WITH HYDRODYNAMICALLY MODIFIED ELECTROOSMOTIC FLOW AND ON-LINE REDUCTION OF SELENIUM(VI) TO SELENIUM(IV) WITH HYDRIDE GENERATION INDUCTIVELY COUPLED PLASMA MASS SPECTROMETRIC DETECTION

    EPA Science Inventory

    Capillary electrophoresis (CE) with hydride generation inductively coupled plasma mass spectrometry was used to determine four arsenicals and two selenium species. Selenate (SeVI) was reduced on-line to selenite (SeIV') by mixing the CE effluent with concentrated HCl. A microporo...

  19. Capabilities of mixed-mode liquid chromatography coupled to inductively coupled plasma mass spectrometry for the simultaneous speciation analysis of inorganic and organically-bound selenium.

    PubMed

    Peachey, Emma; Cook, Ken; Castles, Adrian; Hopley, Christopher; Goenaga-Infante, Heidi

    2009-10-16

    This work investigates for the first time the potential of mixed-mode (anion-exchange with reversed-phase) high performance liquid chromatography coupled to inductively coupled plasma mass spectrometry (ICP-MS) for the simultaneous retention and selective separation of a range of inorganic and organically-bound selenium (Se) species. Baseline separation and detection of selenocystine (SeCys(2)), Se-methyl-selenocysteine (SeMC), selenomethionine (SeMet), methylseleninic acid (MSA), selenite, gamma-glutamyl-methyl-selenocysteine (gamma-glutamyl-SeMC), and selenate in a Se standard mixture by mixed-mode HPLC-ICP-MS was achieved by switching between two citrate mobile phases of different pH and ionic strength within a single chromatographic run of 20 min. Limits of detection obtained for these Se species ranged from 80 ng kg(-1) (for SeMC) to 123 ng kg(-1) (for selenate). Using this approach as developed for selenium speciation, an adequate separation of inorganic and organic As compounds was also achieved. These include arsenite, arsenate, arsenobetaine (AsB) and dimethylarsenic acid (DMA), which may coexist with Se species in biological samples. Application of the newly proposed methodology to the investigation of the elemental species distribution in watercress (used as the model sample) after enzymatic hydrolysis or leaching in water by accelerated solvent extraction (ASE) was addressed. Only SeMet, SeMC and selenate could be tentatively identified in watercress extracts by mixed-mode HPLC-ICP-MS and retention time matching with standards. Recoveries (n=3) of these Se species from samples spiked with standards averaged 102% (for SeMC), 94.9% (for SeMet) and 98.3% (for selenate). Verification of the presence of SeMet and SeMC in an enzymatic watercress extract was achieved by on-line HPLC-ESI MS/MS in selected reaction monitoring (SRM) mode. PMID:19758595

  20. Selenium contents in tobacco and main stream cigarette smoke determined using neutron activation analysis

    SciTech Connect

    Sorak-Pokrajac, M.; Dermelj, M.; Slejkovec, Z.

    1994-01-01

    In the domain of the essential trace elements, the role of selenium is extremely important. As one of the volatile elements it can be partly absorbed through the pulmonary system during smoking and transported to different organs of the body. Thus a knowledge of its concentration levels in various sorts of tobacco and in the smoke of commercial cigarettes, as well as in the same type of cigarettes from plants treated with selenium, is of interest for various research fields. The purpose of this contribution is to present reliable quantitative data on selenium contents in tobacco, soil, and main stream cigarette smoke, obtained by destructive neutron activation analysis.

  1. Quality assurance program for the determination of selenium in foods and diets by instrumental neutron activation

    SciTech Connect

    Zhang, W.H.; Chatt, A.

    1996-12-31

    The biological essentially of selenium for animals was first evidenced in 1957. However, it was not until 1973 that an enzyme called glutathione peroxidase was proven to be a selenoenzyme. At present, selenium is known to be a normal component of several enzymes, proteins, and some aminoacryl transfer nucleic acids. A few selenium compounds have been reported to possess anticarcinogenic properties. There is an increasing interest in understanding the role of selenium in human nutrition and metabolism. Analytical methods are being developed in several laboratories for the determination of total and species-specific selenium in whole blood, serum, urine, soft and hard tissues, food, water, proteins, etc. We have developed several instrumental neutron activation analysis (INAA) methods using the, Dalhousie University SLOWPOKE-2 reactor facility for the determination of parts-per-billion levels of selenium. These methods include cyclic INAA (CINAA) and pseudocyclic INAA (PCINAA) using both conventional and anticoincidence gamma-ray spectrometry. Considering the immense health significance, it is imperative that the selenium levels in foods and diets be measured under an extensive quality assurance program for routine monitoring purposes.

  2. Evaluation of precision and accuracy of selenium measurements in biological materials using neutron activation analysis

    SciTech Connect

    Greenberg, R.R.

    1988-01-01

    In recent years, the accurate determination of selenium in biological materials has become increasingly important in view of the essential nature of this element for human nutrition and its possible role as a protective agent against cancer. Unfortunately, the accurate determination of selenium in biological materials is often difficult for most analytical techniques for a variety of reasons, including interferences, complicated selenium chemistry due to the presence of this element in multiple oxidation states and in a variety of different organic species, stability and resistance to destruction of some of these organo-selenium species during acid dissolution, volatility of some selenium compounds, and potential for contamination. Neutron activation analysis (NAA) can be one of the best analytical techniques for selenium determinations in biological materials for a number of reasons. Currently, precision at the 1% level (1s) and overall accuracy at the 1 to 2% level (95% confidence interval) can be attained at the U.S. National Bureau of Standards (NBS) for selenium determinations in biological materials when counting statistics are not limiting (using the {sup 75}Se isotope). An example of this level of precision and accuracy is summarized. Achieving this level of accuracy, however, requires strict attention to all sources of systematic error. Precise and accurate results can also be obtained after radiochemical separations.

  3. Simultaneous speciation of inorganic arsenic, selenium and tellurium in environmental water samples by dispersive liquid liquid microextraction combined with electrothermal vaporization inductively coupled plasma mass spectrometry.

    PubMed

    Liu, Ying; He, Man; Chen, Beibei; Hu, Bin

    2015-09-01

    A new method based on dispersive liquid liquid microextraction (DLLME) combined with electrothermal vaporization inductively coupled plasma mass spectrometry (ETV-ICP-MS) was developed for the simultaneous speciation of inorganic arsenic (As), selenium (Se) and tellurium (Te) with sodium diethyldithiocarbamate (DDTC) as both chelating reagent and chemical modifier. As(III), Se(IV) and Te(IV) were transformed into DDTC-chelates at pH 7 and extracted into the fine droplets formed by injecting the binary solution of bromobenzene (extraction solvent) and methanol (dispersive solvent) into the sample solution. After phase separation by centrifugation, As(III), Se(IV) and Te(IV) preconcentrated in the organic phase were determined by ETV-ICP-MS. Total inorganic As, Se and Te were obtained by reducing As(V), Se(VI) and Te(VI) to As(III), Se(IV) and Te(IV) with L-cysteine, which were then subjected to the same DLLME-ETV-ICP-MS process. The concentration of As(V), Se(VI), Te(VI) were calculated by subtracting the concentration of As(III), Se(IV) and Te(IV) from the total inorganic As, Se and Te, respectively. The main factors affecting the microextraction efficiency and the vaporization behavior of target species were investigated in detail. Under the optimal conditions, the limits of detection were 2.5, 8.6 and 0.56 ng L(-1) for As(III), Se(IV) and Te(IV), respectively, with the relative standard deviations (n=7) of 8.5-9.7%. The developed method was applied to the speciation of inorganic As, Se and Te in Certified Reference Materials of GSBZ50004-88, GBW(E)080395 and GBW(E)080548 environmental waters, and the determined values are in good agreement with the certified values. The method was also successfully applied to the simultaneous speciation of inorganic As, Se and Te in different environmental water samples with the recoveries in the range of 86.3-107% for the spiked samples. PMID:26003714

  4. Selenium enrichment on Cordyceps militaris link and analysis on its main active components.

    PubMed

    Dong, Jing Z; Lei, C; Ai, Xun R; Wang, Y

    2012-03-01

    To investigate the effects of selenium on the main active components of Cordyceps militaris fruit bodies, selenium-enriched cultivation of C. militaris and the main active components of the fruit bodies were studied. Superoxide dismutase (SOD) activity and contents of cordycepin, cordycepic acid, and organic selenium of fruit bodies were sodium selenite concentration dependent; contents of adenosine and cordycep polysaccharides were significantly enhanced by adding sodium selenite in the substrates, but not proportional to sodium selenite concentrations. In the cultivation of wheat substrate added with 18.0 ppm sodium selenite, SOD activity and contents of cordycepin, cordycepic acid, adenosine, cordycep polysaccharides, and total amino acids were enhanced by 121/145%, 124/74%, 325/520%, 130/284%, 121/145%, and 157/554%, respectively, compared to NS (non-selenium-cultivated) fruit bodies and wild Cordyceps sinensis; organic selenium contents of fruit bodies reached 6.49 mg/100 g. So selenium-enriched cultivation may be a potential way to produce more valuable medicinal food as a substitute for wild C. sinensis. PMID:22246726

  5. Graphene oxide-TiO2 composite solid phase extraction combined with graphite furnace atomic absorption spectrometry for the speciation of inorganic selenium in water samples.

    PubMed

    Zhang, Yanan; Chen, Beibei; Wu, Shaowei; He, Man; Hu, Bin

    2016-07-01

    In this paper, a method of graphene oxide (GO)-TiO2 composite solid phase extraction followed by graphite furnace atomic absorption spectrometry (GFAAS) detection was proposed for the speciation of inorganic selenium in environmental waters. The adsorption behavior of inorganic Se(IV) and Se(VI) on the GO-TiO2(1:1) composite was investigated. It was found that Se(IV) was quantitatively retained on the GO-TiO2 composites within a wide pH range of 0.5-10, while Se(VI) was quantitatively adsorbed on GO-TiO2(1:1) composite at pH 0.5-2, and no obvious adsorption of Se(VI) within the pH range of 4-10 was found. By selecting pH 6.0, Se(IV) could be easily determined. After reduction of Se(VI), total Se was determined by the proposed method, and Se(VI) was calculated as the difference between the total Se and Se(IV). The factors affecting the separation/preconcentration of Se(IV) and Se(VI) were studied. Under the optimum conditions, the isothermal adsorption of Se(IV) on the GO-TiO2(1:1) composite fitted Langmuir model; a linear range over 0.1-12ngmL(-1) was obtained. The limit of detection (LOD) and precision of the method for Se(IV) was 0.04ngmL(-1) and 9.4% (cSe(IV)=0.5ngmL(-1), n=7), respectively. In order to verify the accuracy of the method, a standard water sample (GSBZ50031-94) was analyzed, and the determined value was in a good agreement to the certified value. The established method was applied to inorganic Se speciation in environmental water samples and the recovery of 87.4-102% was obtained for the spiked samples. PMID:27154702

  6. Synchrotron-based X-ray absorption near-edge spectroscopy imaging for laterally resolved speciation of selenium in fresh roots and leaves of wheat and rice

    PubMed Central

    Wang, Peng; Menzies, Neal W.; Lombi, Enzo; McKenna, Brigid A.; James, Simon; Tang, Caixian; Kopittke, Peter M.

    2015-01-01

    Knowledge of the distribution of selenium (Se) species within plant tissues will assist in understanding the mechanisms of Se uptake and translocation, but in situ analysis of fresh and highly hydrated plant tissues is challenging. Using synchrotron-based fluorescence X-ray absorption near-edge spectroscopy (XANES) imaging to provide laterally resolved data, the speciation of Se in fresh roots and leaves of wheat (Triticum aestivum L.) and rice (Oryza sativa L.) supplied with 1 μM of either selenate or selenite was investigated. For plant roots exposed to selenate, the majority of the Se was efficiently converted to C-Se-C compounds (i.e. methylselenocysteine or selenomethionine) as selenate was transported radially through the root cylinder. Indeed, even in the rhizodermis which is exposed directly to the bulk solution, only 12–31% of the Se was present as uncomplexed selenate. The C-Se-C compounds were probably sequestered within the roots, whilst much of the remaining uncomplexed Se was translocated to the leaves—selenate accounting for 52–56% of the total Se in the leaves. In a similar manner, for plants exposed to selenite, the Se was efficiently converted to C-Se-C compounds within the roots, with only a small proportion of uncomplexed selenite observed within the outer root tissues. This resulted in a substantial decrease in translocation of Se from the roots to leaves of selenite-exposed plants. This study provides important information for understanding the mechanisms responsible for the uptake and subsequent transformation of Se in plants. PMID:26019258

  7. Comprehensive speciation of low-molecular weight selenium metabolites in mustard seeds using HPLC-electrospray linear trap/Orbitrap tandem mass spectrometry.

    PubMed

    Ouerdane, Laurent; Aureli, Federica; Flis, Paulina; Bierla, Katarzyna; Preud'homme, Hugues; Cubadda, Francesco; Szpunar, Joanna

    2013-09-01

    An analytical methodology based on high-resolution high mass accuracy electrospray ionization (ESI) tandem MS assisted by Se-specific detection using inductively coupled plasma mass spectrometry (ICP MS) was developed for speciation of selenium (Se) in seeds of black mustard (Brassica nigra) grown on Se-rich soil. Size-exclusion LC-ICP MS allowed the determination of the Se distribution according to the molecular mass and the control of the species stability during extraction. The optimization of hydrophilic interaction of LC and cation-exchange HPLC resulted in analytical conditions making it possible to detect and characterize over 30 Se species using ESI MS, including a number of minor (<0.5%) metabolites. Selenoglucosinolates were found to be the most important class of species accounting for at least 15% of the total Se present and over 50% of all the metabolites. They were found particularly unstable during aqueous extraction leading to the loss of Se by volatilization as methylselenonitriles and methylselenoisothiocyanates identified using gas chromatography (GC) with the parallel ICP MS and atmospheric pressure chemical ionization (APCI) MS/MS detection. However, selenoglucosinolates could be efficiently recovered by extraction with 70% methanol. Other classes of identified species included selenoamino acids, selenosugars, selenosinapine and selenourea derivatives. The three types of reactions leading to the formation of selenometabolites were: the Se-S substitution in the metabolic pathway, oxidative reactions of -SeH groups with endogenous biomolecules, and chemical reactions, e.g., esterification, of Se-containing molecules and other biomolecules through functional groups not involving Se. PMID:23925428

  8. Speciation and chemical activities in superheated sodium borate solutions

    SciTech Connect

    Weres, O. )

    1993-06-01

    The system H[sub 2]O-B[sub 2]O[sub 3]-Na[sub 2]O has been studied experimentally at 277[degrees] and 317[degrees]C. The activities of water and boric acid have been determined at mole ratios Na/B from 0 to 1.5, and total dissolved solids 3 to 80 weight percent. The activity of boric acid has been fitted to within experimental error using a speciation model with eight complex species. This model is consistent with the model previously published by Mesmer et al. The electrolyte properties of the liquid are modelled using the Pitzer-Simonson Model of very concentrated electrolyte solutions. The calculated values of water activity agree with experiment, and the activity of NaOH and pOH have also been calculated. These data will allow prediction of the composition and chemical behavior of sodium borate liquids that may accumulate in the superheated crevices within a steam generator. A modified form of the model is provided for use with MULTEQ. The potassium borate system also was briefly studied at 317[degrees]C, and is adequately described by a model with five complex species. The potassium borate liquid is more alkaline at K/B = 1 than a sodium borate liquid at the same mole ratio, but pOH in the two systems is the same at lower mole ratios.

  9. Spatial Imaging, Speciation, and Quantification of Selenium in theHyperaccumulator Plants Astragalus bisulcatus and Stanleya pinnata

    SciTech Connect

    Freeman, J.L.; Zhang, L.H.; Marcus, M.A.; Fakra, S.; McGrath,S.P.; Pilon-Smits, E.A.H.

    2006-09-01

    Astragalus bisulcatus and Stanleya pinnata hyperaccumulate selenium (Se) up to 1% of plant dry weight. In the field, Se was mostly present in the young leaves and reproductive tissues of both hyperaccumulators. Microfocused scanning x-ray fluorescence mapping revealed that Se was hyperaccumulated in trichomes in young leaves of A. bisulcatus. None of 10 other elements tested were accumulated in trichomes. Micro x-ray absorption spectroscopy and liquid chromatography-mass spectrometry showed that Se in trichomes was present in the organic forms methylselenocysteine (MeSeCys; 53%) and {gamma}-glutamyl-MeSeCys (47%). In the young leaf itself, there was 30% inorganic Se (selenate and selenite) in addition to 70% MeSeCys. In young S. pinnata leaves, Se was highly concentrated near the leaf edge and surface in globular structures that were shown by energy-dispersive x-ray microanalysis to be mainly in epidermal cells. Liquid chromatography-mass spectrometry revealed both MeSeCys (88%) and selenocystathionine (12%) inside leaf edges. In contrast, both the Se accumulator Brassica juncea and the nonaccumulator Arabidopsis thaliana accumulated Se in their leaf vascular tissues and mesophyll cells. Se in hyperaccumulators appears to be mobile in both the xylem and phloem because Se-treated S. pinnata was found to be highly toxic to phloem-feeding aphids, and MeSeCys was present in the vascular tissues of a S. pinnata young leaf petiole as well as in guttation fluid. The compartmentation of organic selenocompounds in specific storage areas in the plant periphery appears to be a unique property of Se hyperaccumulators. The high concentration of Se in the plant periphery may contribute to Se tolerance and may also serve as an elemental plant defense mechanism.

  10. Leaching of boron, arsenic and selenium from sedimentary rocks: II. pH dependence, speciation and mechanisms of release.

    PubMed

    Tabelin, Carlito Baltazar; Hashimoto, Ayaka; Igarashi, Toshifumi; Yoneda, Tetsuro

    2014-03-01

    Sedimentary rocks excavated in Japan from road- and railway-tunnel projects contain relatively low concentrations of hazardous trace elements like boron (B), arsenic (As) and selenium (Se). However, these seemingly harmless waste rocks often produced leachates with concentrations of hazardous trace elements that exceeded the environmental standards. In this study, the leaching behaviors and release mechanisms of B, As and Se were evaluated using batch leaching experiments, sequential extraction and geochemical modeling calculations. The results showed that B was mostly partitioned with the residual/crystalline phase that is relatively stable under normal environmental conditions. In contrast, the majority of As and Se were associated with the exchangeable and organics/sulfides phases that are unstable under oxidizing conditions. Dissolution of water-soluble phases controlled the leaching of B, As and Se from these rocks in the short term, but pyrite oxidation, calcite dissolution and adsorption/desorption reactions became more important in the long term. The mobilities of these trace elements were also strongly influenced by the pH of the rock-water system. Although the leaching of Se only increased in the acidic region, those of B and As were enhanced under both acidic and alkaline conditions. Under strongly acidic conditions, the primarily release mechanism of B, As and Se was the dissolution of mineral phases that incorporated and/or adsorbed these elements. Lower concentrations of these trace elements in the circumneutral pH range could be attributed to their strong adsorption onto minerals like Al-/Fe-oxyhydroxides and clays, which are inherently present and/or precipitated in the rock-water system. The leaching of As and B increased under strongly alkaline conditions because of enhanced desorption and pyrite oxidation while that of Se remained minimal due to its adsorption onto Fe-oxyhydroxides and co-precipitation with calcite. PMID:24370699

  11. The response of broccoli (Brassica oleracea convar. italica) varieties on foliar application of selenium: uptake, translocation, and speciation.

    PubMed

    Šindelářová, Kristýna; Száková, Jiřina; Tremlová, Jana; Mestek, Oto; Praus, Lukáš; Kaňa, Antonín; Najmanová, Jana; Tlustoš, Pavel

    2015-01-01

    A model small-scale field experiment was set up to investigate selenium (Se) uptake by four different varieties of broccoli plants, as well as the effect of Se foliar application on the uptake of essential elements for plants calcium (Ca), copper (Cu), iron (Fe), potassium (K), magnesium (Mg), manganese (Mn), phosphorus (P), sulfur (S), and zinc (Zn). Foliar application of sodium selenate (Na2SeO4) was carried out at two rates (25 and 50 g Se/ha), and an untreated control variant was included. Analyses of individual parts of broccoli were performed, whereby it was found that Se in the plant accumulates mainly in the flower heads and slightly less in the leaves, stems, and roots, regardless of the Se rate and broccoli variety. In most cases, there was a statistically significant increase of Se content in all parts of the plant, while there was no confirmed systematic influence of the addition of Se on the changing intake of other monitored elements. Selenization of broccoli leads to an effective increase in the Se content at a rate of 25 g/ha, whereas the higher rate did not result in a substantial increase of Se content compared to the lower rate in all varieties. Therefore, the rate of 25 g/ha can be recommended as effective to produce broccoli with an increased Se content suitable for consumption. Moreover, Se application resulted in an adequate increase of the main organic compounds of Se, such as selenocystine (SeCys2), selenomethionine (SeMet), and Se-methylselenocysteine (Se-MeSeCys). PMID:26414440

  12. Composition and distribution of the main active components in selenium-enriched fruit bodies of Cordyceps militaris link.

    PubMed

    Dong, Jing Z; Ding, J; Yu, Pei Z; Lei, Can; Zheng, Xiao J; Wang, Y

    2013-04-15

    Selenium-enriched Cordyceps militaris fruit bodies are industrially cultivated as functional food or medicinal food in China and southeast Asia. However, composition of selenium compounds and distribution of the main bioactive components are still unknown. In the selenium-enriched fruit bodies, the main soluble selenium compounds of low molecular weight were identified as SeMet (selenomethionine), and the main selenium compounds bound in proteins were identified as SeMet and SeCys (methylselenocysteine). Trace minerals as Se (selenium), Zn (zinc), Fe (iron) and the main active components as adenosine, cordycepin and carotenoids were mostly distributed in the terminal of fruit bodies, while P (phosphorus) and K (potassium) were evenly distributed in the fruit bodies. The results indicated that terminal of the fruit bodies should be the better materials for production of advanced functional food. So cultivation of relatively short and thick fruit bodies with bigger terminals deserves further research. PMID:23200005

  13. Macrophage Bactericidal Activities against Staphylococcus aureus Are Enhanced In Vivo by Selenium Supplementation in a Dose-Dependent Manner

    PubMed Central

    Aribi, Mourad; Meziane, Warda; Habi, Salim; Boulatika, Yasser

    2015-01-01

    Background Dietary selenium is of fundamental importance to maintain optimal immune function and enhance immunity during infection. To this end, we examined the effect of selenium on macrophage bactericidal activities against Staphylococcus aureus. Methods Assays were performed in golden Syrian hamsters and peritoneal macrophages cultured with S. aureus and different concentrations of selenium. Results Infected and selenium-supplemented animals have significantly decreased levels of serum nitric oxide (NO) production when compared with infected but non-selenium-supplemented animals at day 7 post-infection (p < 0.05). A low dose of 5 ng/mL selenium induced a significant decrease in macrophage NO production, but significant increase in hydrogen peroxide (H2O2) levels (respectively, p = 0.009, p < 0.001). The NO production and H2O2 levels were significantly increased with increasing concentrations of selenium; the optimal macrophage activity levels were reached at 20 ng/mL. The concentration of 5 ng/mL of selenium induced a significant decrease in the bacterial arginase activity but a significant increase in the macrophage arginase activity. The dose of 20 ng/mL selenium induced a significant decrease of bacterial growth (p < 0.0001) and a significant increase in macrophage phagocytic activity, NO production/arginase balance and S. aureus killing (for all comparisons, p < 0.001). Conclusions Selenium acts in a dose-dependent manner on macrophage activation, phagocytosis and bacterial killing suggesting that inadequate doses may cause a loss of macrophage bactericidal activities and that selenium supplementation could enhance the in vivo control of immune response to S. aureus. PMID:26340099

  14. Anomalous antibacterial activity and dye degradation by selenium doped ZnO nanoparticles.

    PubMed

    Dutta, Raj Kumar; Nenavathu, Bhavani Prasad; Talukdar, Soumita

    2014-02-01

    Selenium doped ZnO nanoparticles synthesized by mechanochemical method were spherically shaped of size distribution of 10.2±3.4 nm measured by transmission electron microscopy. Diffused reflectance spectroscopy revealed increase in the band gap, ranging between 3.47 eV and 3.63 eV due to Se doping in ZnO nanoparticles. The antibacterial activity of pristine and Se doped ZnO nanoparticles was attributed to ROS (reactive oxygen species) generation in culture media confirmed by TBARS assay. Compared to complete inhibition of growth by 0.45 mg/mL of pristine ZnO nanoparticles, the batches of 0.45 mg/mL of selenium doped ZnO nanoparticles exhibited only 51% inhibition of growth of Escherichia coli. The reduced antibacterial activity of selenium doped ZnO nanoparticles was attributed to two opposing factors, e.g., ROS generation for inhibition of growth, countered by sustaining growth of E. coli due to availability of Se micronutrients in culture media, confirmed by inductively coupled plasma mass spectrometer measurement. Higher ROS generation by selenium doped ZnO nanoparticles was attributed to creation of oxygen vacancies, confirmed from green emission peak observed at 565 nm. The impact of higher ROS generation by selenium doped ZnO nanoparticles was evident from enhanced photocatalytic degradation of trypan blue dye, than pristine ZnO nanoparticles. PMID:24200949

  15. Exposure histories derived from selenium in otoliths of three cold-water fish species captured downstream from coal mining activity.

    PubMed

    Friedrich, Lisa A; Orr, Patricia L; Halden, Norman M; Yang, Panseok; Palace, Vince P

    2011-10-01

    Establishing exposure to contaminants within a given environment is often difficult for fish species with large home ranges. Chemical analyses of muscle or visceral tissue are useful indicators of recent exposure, but depuration, metabolic transformation, and tissue redistributions can alter temporal resolution. Otoliths are metabolically stable and thus provide complete chemical records within their calcified tissues that, when coupled to the annular structure, can provide temporal resolution for exposure to trace metals. Otoliths from bull trout, cutthroat trout, and mountain whitefish from an area rich in seleniferous soils and with active coal mining activity were analyzed for selenium to determine any history of exposure to elevated levels of selenium. Selenium concentrations in otolith primordia tended to be low, indicating that these fish emerged in low selenium areas. Later life stages showed peaks of high Se concentrations, suggesting that individuals moved into areas of increased selenium later in life. Individuals captured from the same area had a wide variety of selenium exposure profiles, indicating that these fish do not move en masse into and out of high-selenium areas. Year-to-year variability of selenium exposure patterns within an otolith suggests inconsistent utilization of high- and low-selenium areas by the individual. The inconsistent exposure profiles for these fish, in addition to their home range of tens of kilometres, indicate that soft tissue concentrations, while useful indicators of recent exposure, cannot be relied upon to provide a life history recording of exposure. PMID:21899824

  16. Selenium transformation in coal mine spoils

    SciTech Connect

    Atalay, A.; Koll, K.J.

    1990-09-01

    The objective of this part of the study is to investigate the oxidation-reduction (redox) environment that favor the release of selenium from coal mine spoils. It is anticipated that the study will help answer critical questions as to the form, solubility, and mobility of selenium from the spoil site to the surrounding environment. This investigation will evaluate the conditions which favor the speciation of selenium from coal mine spoils as affected by changes in the oxidation states of selenium.

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

    PubMed

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

    2016-01-01

    Selenium, a "dual-surface" element, maintains a very thin line between a level of necessity and harmfulness. Because of this, a deficiency or excess of this element in an organism is dangerous and causes health-related problems, both physically and mentally. The main source of selenium is a balanced diet, with a proper selection of meat and plant products. Meanwhile, the proper assimilation of selenium into these products depends on their bioavailability, bioaccessibility, and/or bioactivity of a given selenium compound. From the time when it was discovered that selenium and its compounds have a significant influence on metabolic processes and in many countries throughout the world, a low quantity of selenium was found in different parts of the environment, pressure was put upon an effective and fast method of supplementing the environment with the help of selenium. This work describes supplementation methods applied with the use of selenium, as well as new ideas for increasing the level of this element in various organisms. Based on the fact that selenium appears in the environment at trace levels, the determination of total amount of selenium or selenium speciation in a given sample demands the selection of appropriate measurement methods. These methods are most often comprised of a sample preparation technique and/or a separation technique as well as a detection system. The work presents information on the subject of analytical methods used for determining selenium and its compounds as well as examples in literature of their application. PMID:24987868

  18. Chemical forms of selenium affect glutatione peroxidase activity in human Caco-2 cell model

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The bioavailability of selenium (Se) is complicated because there are multiple naturally occurring chemical forms of this element in nature. Assessing the ability of a Se source to restore GPX1 activity in laboratory animals and humans is the most commonly used method. To search for an alternative (...

  19. Switchable catalytic activity: selenium-containing peptides with redox-controllable self-assembly properties.

    PubMed

    Miao, Xiaoming; Cao, Wei; Zheng, Wenting; Wang, Jingyu; Zhang, Xiaoli; Gao, Jie; Yang, Chengbiao; Kong, Deling; Xu, Huaping; Wang, Ling; Yang, Zhimou

    2013-07-22

    Mimicking nature: The reversible formation of self-assembled nanostructures of selenium-containing peptides can be controlled by redox triggers (see scheme, VC = vitamin C). As a consequence, the catalytic activity of these peptides is switchable. These results should lead to the development of nature-mimicking smart materials with promising properties. PMID:23784972

  20. 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. PMID:25281102

  1. Selenium speciation using capillary electrophoresis coupled with modified electrothermal atomic absorption spectrometry after selective extraction with 5-sulfosalicylic acid functionalized magnetic nanoparticles.

    PubMed

    Yan, Lizhen; Deng, Biyang; Shen, Caiying; Long, Chanjuan; Deng, Qiufen; Tao, Chunyao

    2015-05-22

    A new method for selenium speciation in fermented bean curd wastewater and juice was described. This method involved sample extraction with 5-sulfosalicylic acid (SSA)-functionalized silica-coated magnetic nanoparticles (SMNPs), capillary electrophoresis (CE) separation, and online detection with a modified electrothermal atomic absorption spectrometry (ETAAS) system. The modified interface for ETAAS allowed for the introduction of CE effluent directly through the end of the graphite tube. Elimination of the upper injection hole of the graphite tube reduced the loss of the anlayte and enhanced the detection sensitivity. The SSA-SMNPs were synthesized and used to extract trace amounts of selenite [Se(IV)], selenite [Se(VI)], selenomethionine (SeMet), and selenocystine (SeCys2) from dilute samples. The concentration enrichment factors for Se(VI), Se(IV), SeMet, and SeCys2 were 21, 29, 18, and 12, respectively, using the SSA-SMNPs extraction. The limits of detection for Se(VI), Se(IV), SeMet, and SeCys2 were 0.18, 0.17, 0.54, 0.49ngmL(-1), respectively. The RSD values (n=6) of method for intraday were observed between 0.7% and 2.9%. The RSD values of method for interday were less than 3.5%. The linear range of Se(VI) and Se(IV) were in the range of 0.5-200ngmL(-1), and the linear ranges of SeMet and SeCys2 were 2-500 and 2-1000ngmL(-1), respectively. The detection limits of this method were improved by 10 times due to the enrichment by the SSA-SMNP extraction. The contents of Se(VI) and Se(IV) in fermented bean curd wastewater were measured as 3.83 and 2.62ngmL(-1), respectively. The contents of Se(VI), Se(IV), SeMet, and SeCys2 in fermented bean curd juice were determined as 6.39, 4.08, 2.77, and 4.00ngmL(-1), respectively. The recoveries were in the range of 99.14-104.5% and the RSDs (n=6) of recoveries between 0.82% and 3.5%. PMID:25865795

  2. The effects of selenium on glutathione peroxidase activity and radioprotection in mammalian cells

    SciTech Connect

    Diamond, A.M.; Murray, J.L.; Dale, P.; Tritz, R.; Grdina, D.J.

    1995-09-05

    The media of representative mammalian cell lines were supplemented with low levels of selenium in the form of sodium selenite in order to investigate the effects of selenium on mammalian cells. Following incubation in 30 nM sodium selenite, these cells were assayed for changes in glutathione peroxidase (GPx) activity. The cells examined included NIH 3T3 mouse fibroblasts, PC12 rat sympathetic precursor cells, SupT-1 human lymphocytes, MCF-7{sup adr} human breast carcinoma cells and AA8 Chinese hamster ovary cells. Selenium supplementation resulted in a marginal increase in GPx activity for the NIH 3T3, MCF-7{sup adr} and Supt-1 cells but stimulated GPx activity approximately 5-fold in PC12 and AA8 cells. AA8 cells were selected to evaluate whether selenium supplementation was radioprotective against {sup 60}cobalt gamma irradiation. Protection against radiation-induced mutation was measured by evaluating mutation frequency at the hprt locus. In this assay, preincubation of AA8 CHO cells significantly protected these cells from exposure to 8 Gy.

  3. Effect of selenium-enriched probiotics on laying performance, egg quality, egg selenium content, and egg glutathione peroxidase activity.

    PubMed

    Pan, Cuiling; Zhao, Yuxin; Liao, Shengfa F; Chen, Fu; Qin, Shunyi; Wu, Xianshi; Zhou, Hong; Huang, Kehe

    2011-11-01

    A 35-day experiment was conducted to evaluate the effect of selenium-enriched probiotics (SP) on laying performance, egg quality, egg selenium (Se) content, and egg glutathione peroxidase (GPX) activity. Five hundred 58-week-old Rohman laying hens were randomly allotted to 5 dietary treatments of 100 each. Each treatment had 5 replicates, and each replicate had 5 cages with 4 hens per cage. The SP was supplemented to a corn-soybean-meal basal diet at 3 different levels that supplied total Se at 0.2, 0.5, and 1.0 mg/kg. The basal diet served as a blank control, while the basal diet with supplemental probiotics served as a probiotics control. The results showed that dietary SP supplementation not only increased (p < 0.05) the rate of egg laying, day egg weight, mean egg weight, egg Se content, and egg GPX activity but also decreased (p < 0.05) the feed:egg ratio and egg cholesterol content. The egg Se content was gradually increased (p < 0.05) along with the increasing level of dietary Se. The SP supplementation also slowed down (p < 0.05) the drop of Haugh units (HU) of eggs stored at room temperature. The egg GPX activity had a positive correlation (p < 0.01) with egg Se content and a negative correlation (p < 0.01) with egg HU drop. These results suggested that Se contents, GPX activity, and HU of eggs were affected by the dietary Se level, whereas the egg-laying performance and egg cholesterol content were affected by the dietary probiotics. It was concluded that this SP is an effective feed additive that combines the organic Se benefit for hen and human health with the probiotics benefit for laying hen production performance. It was also suggested that the eggs from hens fed this SP can serve as a nutraceutical food with high Se and low cholesterol contents for both healthy people and patients with hyperlipidemia, fatty liver, or cardiovascular disease. PMID:21942342

  4. 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

  5. Simultaneous quantitation and identification of organic and inorganic selenium in diet supplements by liquid chromatography with tandem mass spectrometry.

    PubMed

    Zembrzuska, Joanna; Matusiewicz, Henryk; Polkowska-Motrenko, Halina; Chajduk, Ewelina

    2014-01-01

    A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed for selenium speciation in dietary supplements. Chromatographic separation was performed on a TSK-Gel ODS-100V column using a mixture of 5mM ammonium acetate water solution and methanol as a mobile phase. Conditions chosen for this process allowed to separate all investigated chemical compounds of selenium: seleno-l-methionine, methyl-seleno-l-cysteine, l-selenocystine, methaneseleninic acid, selenite and selenate. A tandem mass spectrometer with an ion trap operating in negative or positive ion mode according to the selenium form being determined was used as a detector. Three extraction procedures: water extraction, enzymatic hydrolysis and sequential extraction were used for preparation of samples for the determination of the actual forms of selenium in diet supplements. The developed method was used for analysis of six dietary supplements containing selenium bought in a pharmacy and supermarket. Apart from speciation analysis of selenium content in supplements total selenium content was determined using instrumental neutron activation analysis (INAA). All expected forms of selenium except for selenite were determined using LC-MS/MS technique. It should be stressed that amounts of selenate were smaller than expected. PMID:24001829

  6. Selenium status, lipid peroxides concentration, and glutathione peroxidase activity in the blood of power station and rubber factory workers

    SciTech Connect

    Zachara, B.A.; Wasowicz, W.; Sklodowska, M.; Gromadzinska, J.

    1987-07-01

    Concentration of selenium in whole blood and plasma, lipid peroxides in plasma, and glutathione peroxidase activities in red blood cell hemolysates and plasma were determined in 49 coal power plant workers and in 50 rubber factory workers. The results were compared with those obtained for 58 nonindustrial controls. Whole blood selenium was significantly lower and plasma lipid peroxides were significantly higher in power plant workers when compared to the nonindustrial group. In the rubber factory workers, whole blood selenium and red blood cells and plasma glutathione peroxidase activities were significantly lower than in the control group. Urinary output of selenium was also significantly decreased in rubber factory workers. Slightly elevated lipid peroxides were also observed in that group. It seems reasonable to conclude that the lower blood selenium and decreased urinary output of this element may result from increased loss of selenium with perspiration. No correlation has been observed between selenium concentration and glutathione peroxidase activity and between enzyme activity and lipid peroxides concentration in the industrial group.

  7. Anticancer activity of biostabilized selenium nanorods synthesized by Streptomyces bikiniensis strain Ess_amA-1

    PubMed Central

    Ahmad, Maged Sayed; Yasser, Manal Mohamed; Sholkamy, Essam Nageh; Ali, Ali Mohamed; Mehanni, Magda Mohamed

    2015-01-01

    Selenium is an important component of human diet and a number of studies have declared its chemopreventive and therapeutic properties against cancer. However, very limited studies have been conducted about the properties of selenium nanostructured materials in comparison to other well-studied selenospecies. Here, we have shown that the anticancer property of biostabilized selenium nanorods (SeNrs) synthesized by applying a novel strain Ess_amA-1 of Streptomyces bikiniensis. The strain was grown aerobically with selenium dioxide and produced stable SeNrs with average particle size of 17 nm. The optical, structural, morphological, elemental, and functional characterizations of the SeNrs were carried out using techniques such as UV-vis spectrophotometry, transmission electron microscopy, energy dispersive X-ray spectrometry, and Fourier transform infrared spectrophotometry, respectively. The MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay revealed that the biosynthesized SeNrs induces cell death of Hep-G2 and MCF-7 human cancer cells. The lethal dose (LD50%) of SeNrs on Hep-G2 and MCF-7 cells was recorded at 75.96 μg/mL and 61.86 μg/mL, respectively. It can be concluded that S. bikiniensis strain Ess_amA-1 could be used as renewable bioresources of biosynthesis of anticancer SeNrs. A hypothetical mechanism for anticancer activity of SeNrs is also proposed. PMID:26005349

  8. Bacterial activities driving arsenic speciation and solubility in marine sediments

    NASA Astrophysics Data System (ADS)

    Battaglia-Brunet, F.; Seby, F.; Crouzet, C.; Joulian, C.; Mamindy-Pajany, Y.; Guezennec, A. G.; Hurel, C.; Marmier, N.; Bataillard, P.

    2012-04-01

    Harbour and marina sediments represent particular environments, with high concentrations in organic carbon and pollutants. Over 50 million m3 of marine sediments are dredged every year in French maritime and commercial ports, to maintain the water depth suitable for navigation, and the most part of them is discharged in deeper sea zones. The present study aimed to elucidate, using a range of complementary approaches, the influence of bacterial activity on arsenic speciation and mobility in marina sediments. Two sites were considered: L'Estaque, impacted by metallurgical activities and by the commercial port of Marseille, and St-Mandrier, less polluted, affected by classical chemical pollutants associated to professional and recreational boating. Arsenic concentration was noticeably higher in l'Estaque sediment (200-350 mg/kg) than in St-Mandrier sediment (15-50 mg/kg). In the solid phases, As(III) was the dominant species in L'Estaque sediment, whereas As(V) was the main form in St Mandrier sediment. At both sites, arsenic was the major trace element detected in interstitial water. Free sulfide and thio-arsenic complexes were detected in the interstitial water of l'Estaque sediment, suggesting a role of sulfate-reduction bacterial activity on arsenic solubility. Anaerobic microcosm experiments confirmed this hypothesis, as stimulation of sulfate-reduction induced a dramatic increase of arsenic concentration in the liquid phase, linked to the formation of soluble thio-arsenic complexes. Nevertheless, microcosms performed in aerobic conditions showed that bacterial activity globally decreased the transfer of arsenic from the sediment toward the overlying water. A red-brown fine layer developed at the sediment-water interface. Altogether, these results suggest that the sediment-water interface zone and the close transition area between aerobic and anaerobic conditions host intense biogeochemical reactions involving As, Fe and S species. These reactions most probably

  9. Effect of selenium deficiency on hepatic type I 5-iodothyronine deiodinase activity and hepatic thyroid hormone levels in the rat.

    PubMed Central

    Beckett, G J; Russell, A; Nicol, F; Sahu, P; Wolf, C R; Arthur, J R

    1992-01-01

    Selenium deficiency in rats for a period of up to 6 weeks inhibited both the production of 3,3',5-tri-iodothyronine (T3) from thyroxine (T4) (5'-deiodination) and also the catabolism of T3 to 3,3'-di-iodothyronine (5-deiodination) in liver homogenates. The hepatic stores of T3 were decreased by only 8% in selenium deficiency, despite the T3 production rate from T4 being only 7% of the rate found in selenium-supplemented rats. Hepatic glutathione S-transferase (GST) activity was increased in both hypothyroidism and selenium deficiency, but apparently by different mechanisms, since mRNA expression for this family of enzymes was lowered by hypothyroidism and increased in selenium deficiency. It is concluded that, since both T3 production and catabolism are inhibited by selenium deficiency, there is little change in hepatic T3 stores, and therefore the changes in the activity of certain hepatic enzymes, such as GST, that are found in selenium deficiency are not the result of tissue hypothyroidism. Images Fig. 1. PMID:1546962

  10. Addition of Selenium Nanoparticles to Electrospun Silk Scaffold Improves the Mammalian Cell Activity While Reducing Bacterial Growth

    PubMed Central

    Chung, Stanley; Ercan, Batur; Roy, Amit K.; Webster, Thomas J.

    2016-01-01

    Silk possesses many beneficial wound healing properties, and electrospun scaffolds are especially applicable for skin applications, due to their smaller interstices and higher surface areas. However, purified silk promotes microbial growth. Selenium nanoparticles have shown excellent antibacterial properties and are a novel antimicrobial chemistry. Here, electrospun silk scaffolds were doped with selenium nanoparticles to impart antibacterial properties to the silk scaffolds. Results showed significantly improved bacterial inhibition and mild improvement in human dermal fibroblast metabolic activity. These results suggest that the addition of selenium nanoparticles to electrospun silk is a promising approach to improve wound healing with reduced infection, without relying on antibiotics. PMID:27471473

  11. Oral selenium supplementation has no effect on PSA velocity in men undergoing active surveillance for localized prostate cancer

    PubMed Central

    Stratton, M. S.; Algotar, A. M.; Ranger-Moore, J.; Stratton, S. P.; Slate, E.; Hsu, C.H; Thompson, P.A.; Clark, L. C.; Ahmann, F. R.

    2015-01-01

    Introduction The Nutritional Prevention of Cancer Trial demonstrated a 52% lower incidence of prostate cancer in men supplemented with selenium. As a result, our study was designed to assess whether selenium supplementation attenuates the progression of prostate cancer. Methods A Phase 2 randomized, double-blind, placebo-controlled clinical trial was conducted in men with localized non-metastatic prostate cancer who had elected to forgo active treatment and be followed by active surveillance. A total of 140 men were randomized to placebo (n=46), 200 μg/day (n=47) or 800 μg/day (n=47) selenium p.o. (as selenized yeast) and followed every 3 months for up to 5 years. PSA velocity was used as a marker of prostate cancer progression and was estimated using mixed effects regression. Results Adjusting for age, body mass index, baseline selenium, smoking, baseline PSA, race, PSA method, and Gleason score; PSA velocities for 200 μg/day and 800 μg/day treatment groups were not statistically significantly different from placebo (p = 0.32 and p = 0.61 respectively). In the highest quartile of baseline selenium, men supplemented with 800 μg selenium demonstrated PSA velocity statistically significantly higher as compared to placebo (p = 0.018). Conclusions Selenium supplementation did not show a protective effect on PSA velocity in subjects with localized prostate cancer. On the contrary, supplementation with high dose selenium was observed to be a risk factor for increased PSA velocity in men with high baseline plasma selenium concentrations. Trial registration clinicaltrials.gov (NCT00752739) PMID:20647337

  12. Simultaneous speciation of selenium and sulfur species in selenized odorless garlic (Allium sativum L. Shiro) and shallot (Allium ascalonicum) by HPLC-inductively coupled plasma-(octopole reaction system)-mass spectrometry and electrospray ionization-tandem mass spectrometry.

    PubMed

    Ogra, Yasumitsu; Ishiwata, Kazuya; Iwashita, Yuji; Suzuki, Kazuo T

    2005-11-01

    The simultaneous speciation of selenium and sulfur in selenized odorless garlic (Allium sativum L. Shiro) and a weakly odorous Allium plant, shallot (Allium ascalonicum), was performed by means of a hyphenated technique, a HPLC coupled with an inductively coupled plasma-mass spectrometry (HPLC-ICP-MS) equipped with an octopole reaction system (ORS). The aqueous extracts of them contained the common seleno compound that was identified as gamma-glutamylmethylselenocysteine by an electrospray ionization-tandem mass spectrometry (ESI-MS/MS). Normal garlic contains alliin as the major sulfur-containing compound, which is the biological precursor of the garlic odorant, allicin. Alliin, however, was not detected in the extracts of the selenized odorless garlic. At least, four unidentified sulfur-containing compounds were detected in odorless garlic and shallot. Moreover, these Allium plants showed chemopreventive effects against human leukemia cells. PMID:16233877

  13. Selenium Sulfide

    MedlinePlus

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

  14. Selenoprotein Transcript Level and Enzyme Activity as Biomarkers for Selenium Status and Selenium Requirements in the Turkey (Meleagris gallopavo).

    PubMed

    Taylor, Rachel M; Sunde, Roger A

    2016-01-01

    The current National Research Council (NRC) selenium (Se) requirement for the turkey is 0.2 μg Se/g diet. The sequencing of the turkey selenoproteome offers additional molecular biomarkers for assessment of Se status. To determine dietary Se requirements using selenoprotein transcript levels and enzyme activities, day-old male turkey poults were fed a Se-deficient diet supplemented with graded levels of Se (0, 0.025, 0.05, 0.1, 0.2, 0.3, 0.4, 0.5, 0.75, 1.0 μg Se/g diet) as selenite, and 12.5X the vitamin E requirement. Poults fed less than 0.05 μg Se/g diet had a significantly reduced rate of growth, indicating the Se requirement for growth in young male poults is 0.05 μg Se/g diet. Se deficiency decreased plasma GPX3 (glutathione peroxidase), liver GPX1, and liver GPX4 activities to 2, 3, and 7%, respectively, of Se-adequate levels. Increasing Se supplementation resulted in well-defined plateaus for all blood, liver and gizzard enzyme activities and mRNA levels, showing that these selenoprotein biomarkers could not be used as biomarkers for supernutritional-Se status. Using selenoenzyme activity, minimum Se requirements based on red blood cell GPX1, plasma GPX3, and pancreas and liver GPX1 activities were 0.29-0.33 μg Se/g diet. qPCR analyses using all 10 dietary Se treatments for all 24 selenoprotein transcripts (plus SEPHS1) in liver, gizzard, and pancreas found that only 4, 4, and 3 transcripts, respectively, were significantly down-regulated by Se deficiency and could be used as Se biomarkers. Only GPX3 and SELH mRNA were down regulated in all 3 tissues. For these transcripts, minimum Se requirements were 0.07-0.09 μg Se/g for liver, 0.06-0.15 μg Se/g for gizzard, and 0.13-0.18 μg Se/g for pancreas, all less than enzyme-based requirements. Panels based on multiple Se-regulated transcripts were effective in identifying Se deficiency. These results show that the NRC turkey dietary Se requirement should be raised to 0.3 μg Se/g diet. PMID:27008545

  15. Selenoprotein Transcript Level and Enzyme Activity as Biomarkers for Selenium Status and Selenium Requirements in the Turkey (Meleagris gallopavo)

    PubMed Central

    Taylor, Rachel M.; Sunde, Roger A.

    2016-01-01

    The current National Research Council (NRC) selenium (Se) requirement for the turkey is 0.2 μg Se/g diet. The sequencing of the turkey selenoproteome offers additional molecular biomarkers for assessment of Se status. To determine dietary Se requirements using selenoprotein transcript levels and enzyme activities, day-old male turkey poults were fed a Se-deficient diet supplemented with graded levels of Se (0, 0.025, 0.05, 0.1, 0.2, 0.3, 0.4, 0.5, 0.75, 1.0 μg Se/g diet) as selenite, and 12.5X the vitamin E requirement. Poults fed less than 0.05 μg Se/g diet had a significantly reduced rate of growth, indicating the Se requirement for growth in young male poults is 0.05 μg Se/g diet. Se deficiency decreased plasma GPX3 (glutathione peroxidase), liver GPX1, and liver GPX4 activities to 2, 3, and 7%, respectively, of Se-adequate levels. Increasing Se supplementation resulted in well-defined plateaus for all blood, liver and gizzard enzyme activities and mRNA levels, showing that these selenoprotein biomarkers could not be used as biomarkers for supernutritional-Se status. Using selenoenzyme activity, minimum Se requirements based on red blood cell GPX1, plasma GPX3, and pancreas and liver GPX1 activities were 0.29–0.33 μg Se/g diet. qPCR analyses using all 10 dietary Se treatments for all 24 selenoprotein transcripts (plus SEPHS1) in liver, gizzard, and pancreas found that only 4, 4, and 3 transcripts, respectively, were significantly down-regulated by Se deficiency and could be used as Se biomarkers. Only GPX3 and SELH mRNA were down regulated in all 3 tissues. For these transcripts, minimum Se requirements were 0.07–0.09 μg Se/g for liver, 0.06–0.15 μg Se/g for gizzard, and 0.13–0.18 μg Se/g for pancreas, all less than enzyme-based requirements. Panels based on multiple Se-regulated transcripts were effective in identifying Se deficiency. These results show that the NRC turkey dietary Se requirement should be raised to 0.3 μg Se/g diet. PMID

  16. Effects of dietary selenium supplementation on tissue selenium distribution and glutathione peroxidase activity in Chinese Ring necked Pheasants.

    PubMed

    Juniper, D T; Bertin, G

    2013-04-01

    The objective of this study was to determine the concentration of total selenium (Se) and the proportions of total Se comprised as selenomethionine (SeMet) and selenocysteine (SeCys) in the postmortem tissues of female pheasants (Phasianus Colchicus Torquator) offered diets that contained graded additions of selenised-enriched yeast (SY) or a single comparative dose of sodium selenite (SS). Thiobarbituric acid reactive substances (TBARS) and tissue glutathione peroxidase (GSH-Px) activity of breast (Pectoralis Major) were assessed at 0 and 5 days postmortem. A total of 216 female pheasant chicks were enrolled into the study. Twenty-four birds were euthanased at the start of the study, and samples of blood, breast muscle, leg muscle (M. Peroneus Longus and M. Gastrocnemius), heart, liver, kidney and gizzard were collected for determination of total Se. Remaining birds were blocked by live weight and randomly allocated to one of four dietary treatments (n = 48 birds/treatment) that either differed in Se source (SY v. SS) or dose (control (0.17 mg total Se/kg), SY-L and SS-L (0.3 mg/kg total Se as SY and SS, respectively) and SY-H (0.45 mg total Se/kg)). Following 42 and 91 days of treatment, 24 birds per treatment were euthanased, and samples of blood, breast muscle, leg muscle, heart, liver, kidney and gizzard were retained for determination of total Se and the proportion of total Se comprised as SeMet or SeCys. Whole blood GSH-Px activity was determined at each time point. Tissue GSH-Px activity and TBARS were determined in breast tissue at the end of the study. There were increases in both blood and tissues to the graded addition of SY to the diet (P < 0.001), but the same responses were not apparent with the blood and tissues of selenite-supplemented birds receiving a comparable dose (SY-L v. SS-L). Although there were differences between tissue types in the distribution of SeMet and SeCys, there were few differences between treatments. There were effects of

  17. High-performance liquid chromatography-ultrasonic nebulizer high-power nitrogen microwave-induced plasma mass spectrometry, real-time on-line coupling for selenium speciation analysis.

    PubMed

    Chatterjee, Amit; Shibata, Yasuyuki; Tao, Hiroaki; Tanaka, Atsushi; Morita, Masatoshi

    2004-07-01

    The coupling of a high-power nitrogen (N2) microwave-induced plasma (MIP) mass spectrometry--(MS) (1.3 kW) with high-performance liquid chromatography, connected with concentric nebulizer (CN), ultrasonic nebulizer (USN) and a hydride generation (HG) systems, for the optimization and determination of selenium compounds, has been carried out. The MIP-MS system fulfils the ideal requirement being an on-line real-time chromatographic detector for Se speciation analysis. Interchanging of MIP-MS system fabricated nebulizer (concentric) with an ultrasonic nebulizer increases about 3.4-12 (peak height) and 6.5-10 (peak area) times ion signals for the selenium compounds. The detection limits for selenate, selenite, trimethylselenonium ion (TmSe), selenomethionine (Semet) and selenoethionine (Seet) (in Milli-Q-water) obtained with the optimized HPLC-USN-N2MIP-MS system are 0.11, 0.14, 0.09, 0.14 and 0.10 microg L(-1), respectively, about 12-48 times lower than the HPLC-CN-MIP-MS and 1.5-4.4 (peak height) times lower compared to the HPLC-CN-inductively coupled plasma (ICP)-MS coupling. Considering peak area, the repeatability (R.S.D. for three successive analyses) and intermediate precision (R.S.D. for three successive analyses performed on three different days), achieved for five Se compounds are 0.8-5.6, and 1.1-5.9%, comparable with the HPLC-CN-ICP-MS, HPLC-HG-MIP-MS and HPLC-CN-MIP-MS systems. The combined HPLC-USN-N2MIP-MS has been adequately applied for the determination of Se compounds in certified National Institute for Environmental studies human urine CRM No. 18. The results reasonably agree with the HPLC-CN-ICP-MS values. This encouraging combination may be an alternative ion source of mass spectrometry for coming generation in regard to the selenium speciation analysis. PMID:15296393

  18. Selenoprotein Transcript Level and Enzyme Activity as Biomarkers for Selenium Status and Selenium Requirements of Chickens (Gallus gallus)

    PubMed Central

    Li, Jin-Long; Sunde, Roger A.

    2016-01-01

    The NRC selenium (Se) requirement for broiler chicks is 0.15 μg Se/g diet, based primarily on weight gain and feed intake studies reported in 1986. To determine Se requirements in today’s rapidly growing broiler chick, day-old male chicks were fed Se-deficient basal diets supplemented with graded levels of Se (0, 0.025, 0.05, 0.075, 0.1, 0.2, 0.3, 0.5, 0.75, and 1.0 μg Se/g) as Na2SeO3 (5/treatment). Diets contained 15X the vitamin E requirement, and there were no gross signs of Se-deficiency. At 29 d, Se-deficient chicks weighed 62% of Se-supplemented chicks; 0.025 μg Se/g reversed this effect, indicating a minimum Se requirement of 0.025 μg Se/g diet for growth for male broiler chicks. Enzyme activities in Se-deficient chicks for plasma GPX3, liver and gizzard GPX1, and liver and gizzard GPX4 decreased dramatically to 3, 2, 5, 10 and 5%, respectively, of Se-adequate levels, with minimum Se requirements of 0.10–0.13 μg Se/g, and with defined plateaus above these levels. Pancreas GPX1 and GPX4 activities, however, lacked defined plateaus, with breakpoints at 0.3 μg Se/g. qPCR measurement of all 24 chicken selenoprotein transcripts, plus SEPHS1, found that SEPP1 in liver, GPX3 in gizzard, and SEPP1, GPX3 and SELK in pancreas were expressed at levels comparable to housekeeping transcripts. Only 33%, 25% and 50% of selenoprotein transcripts were down-regulated significantly by Se deficiency in liver, gizzard and pancreas, respectively. No transcripts could be used as biomarkers for supernutritional Se status. For export selenoproteins SEPP1 and GPX3, tissue distribution, high expression and Se-regulation clearly indicate unique Se metabolism, which may underlie tissues targeted by Se deficiency. Based on enzyme activities in liver, gizzard, and plasma, the minimum Se requirement in today’s broiler chick is 0.15 μg Se/g diet; pancreas data indicate that the Se requirement should be raised to 0.2 μg Se/g diet to provide a margin of safety. PMID:27045754

  19. Selenoprotein Transcript Level and Enzyme Activity as Biomarkers for Selenium Status and Selenium Requirements of Chickens (Gallus gallus).

    PubMed

    Li, Jin-Long; Sunde, Roger A

    2016-01-01

    The NRC selenium (Se) requirement for broiler chicks is 0.15 μg Se/g diet, based primarily on weight gain and feed intake studies reported in 1986. To determine Se requirements in today's rapidly growing broiler chick, day-old male chicks were fed Se-deficient basal diets supplemented with graded levels of Se (0, 0.025, 0.05, 0.075, 0.1, 0.2, 0.3, 0.5, 0.75, and 1.0 μg Se/g) as Na2SeO3 (5/treatment). Diets contained 15X the vitamin E requirement, and there were no gross signs of Se-deficiency. At 29 d, Se-deficient chicks weighed 62% of Se-supplemented chicks; 0.025 μg Se/g reversed this effect, indicating a minimum Se requirement of 0.025 μg Se/g diet for growth for male broiler chicks. Enzyme activities in Se-deficient chicks for plasma GPX3, liver and gizzard GPX1, and liver and gizzard GPX4 decreased dramatically to 3, 2, 5, 10 and 5%, respectively, of Se-adequate levels, with minimum Se requirements of 0.10-0.13 μg Se/g, and with defined plateaus above these levels. Pancreas GPX1 and GPX4 activities, however, lacked defined plateaus, with breakpoints at 0.3 μg Se/g. qPCR measurement of all 24 chicken selenoprotein transcripts, plus SEPHS1, found that SEPP1 in liver, GPX3 in gizzard, and SEPP1, GPX3 and SELK in pancreas were expressed at levels comparable to housekeeping transcripts. Only 33%, 25% and 50% of selenoprotein transcripts were down-regulated significantly by Se deficiency in liver, gizzard and pancreas, respectively. No transcripts could be used as biomarkers for supernutritional Se status. For export selenoproteins SEPP1 and GPX3, tissue distribution, high expression and Se-regulation clearly indicate unique Se metabolism, which may underlie tissues targeted by Se deficiency. Based on enzyme activities in liver, gizzard, and plasma, the minimum Se requirement in today's broiler chick is 0.15 μg Se/g diet; pancreas data indicate that the Se requirement should be raised to 0.2 μg Se/g diet to provide a margin of safety. PMID:27045754

  20. Pro198Leu polymorphism affects the selenium status and GPx activity in response to Brazil nut intake.

    PubMed

    Cardoso, Bárbara R; Busse, Alexandre L; Hare, Dominic J; Cominetti, Cristiane; Horst, Maria A; McColl, Gawain; Magaldi, Regina M; Jacob-Filho, Wilson; Cozzolino, Silvia M F

    2016-02-01

    Selenoproteins play important roles in antioxidant mechanisms, and are thus hypothesised to have some involvement in the pathology of certain types of dementia. Mild cognitive impairment (MCI) and Alzheimer's disease (AD) are both thought to involve impaired biological activity of certain selenoproteins. Previously, supplementation with a selenium-rich Brazil nut (Bertholletia excelsa) has shown potential in reducing cognitive decline in MCI patients, and could prove to be a safe and effective nutritional approach early in the disease process to slow decline. Here, we have conducted a pilot study that examined the effects of a range of single nucleotide polymorphisms (SNPs) in genes encoding the selenoproteins glutathione peroxidase (GPX1) and selenoprotein P (SEPP) in response to selenium supplementation via dietary Brazil nuts, including selenium status, oxidative stress parameters and GPX1 and SEPP gene expression. Our data suggest that GPX1 Pro198Leu rs1050450 genotypes may differentially affect the selenium status and GPx activity. Moreover, rs7579 and rs3877899 SNPs in SEPP gene, as well as GPX1 rs1050450 genotypes can influence the expression of GPX1 and SEPP mRNA in response to Brazil nuts intake. This small study gives cause for larger investigations into the role of these SNPs in both the selenium status and response to selenium dietary intake, especially in chronic degenerative conditions like MCI and AD. PMID:26661784

  1. Selenium modification of β-lactoglobulin (β-Lg) and its biological activity.

    PubMed

    Zheng, GuoQiang; Liu, HaoYu; Zhu, ZhenYuan; Zheng, Jie; Liu, AnJun

    2016-08-01

    β-Lg is a major whey protein in cow's milk. This study was aimed to find a new kind of organic selenium compound synthesized with β-Lg and selenium dioxide as raw materials under the conditions of vacuum and low temperature. Fourier transformed infrared spectroscopy revealed that seleno-β-lactoglobulin (Se-β-Lg) displayed a strong band at 878cm(-1), belonging to SeO. Circular dichroism spectra results indicated that the conformation of Se-β-Lg was transformed and α-helical, and unordered structures were increased by 9% and 11.2%, respectively, while β-sheet and β-turn were reduced by 14.2% and 6%, respectively. Electrophoresis and matrix-assisted laser desorption/ionization time of flight mass spectrometry results showed that there were two protein bands (1-Seβ-Lg and 2-Seβ-Lg) in Se-β-Lg, only one β-Lg connected with selenate in 1-Seβ-Lg, but two β-Lgs, connected to each other, and with selenate, in 2-Seβ-Lg. Morphological observation and hematoxylin and eosin staining indicated that Se-β-lg could induce K562 cell apoptosis. These results indicated that Se-β-Lg could be synthesized by selenium conjugating β-Lg and it had antitumor activity. PMID:26988499

  2. Selenium transformation in coal mine spoils. Quarterly report

    SciTech Connect

    Atalay, A.; Koll, K.J.

    1990-09-01

    The objective of this part of the study is to investigate the oxidation-reduction (redox) environment that favor the release of selenium from coal mine spoils. It is anticipated that the study will help answer critical questions as to the form, solubility, and mobility of selenium from the spoil site to the surrounding environment. This investigation will evaluate the conditions which favor the speciation of selenium from coal mine spoils as affected by changes in the oxidation states of selenium.

  3. Anti-biofilm activity of biogenic selenium nanoparticles and selenium dioxide against clinical isolates of Staphylococcus aureus, Pseudomonas aeruginosa, and Proteus mirabilis.

    PubMed

    Shakibaie, Mojtaba; Forootanfar, Hamid; Golkari, Yaser; Mohammadi-Khorsand, Tayebe; Shakibaie, Mohammad Reza

    2015-01-01

    The aim of the present study was to investigate the anti-biofilm activity of biologically synthesized selenium nanoparticles (Se NPs) against the biofilm produced by clinically isolated bacterial strains compared to that of selenium dioxide. Thirty strains of Staphylococcus aureus, Pseudomonas aeruginosa, and Proteus mirabilis were isolated from various specimens of the patients hospitalized in different hospitals (Kerman, Iran). Quantification of the biofilm using microtiter plate assay method introduced 30% of S. aureus, 13% of P. aeruginosa and 17% of P. mirabilis isolates as severely adherent strains. Transmission electron micrograph (TEM) of the purified Se NPs (produced by Bacillus sp. MSh-1) showed individual and spherical nano-structure in the size range of 80-220nm. Obtained results of the biofilm formation revealed that selenium nanoparticles inhibited the biofilm of S. aureus, P. aeruginosa, and P. mirabilis by 42%, 34.3%, and 53.4%, respectively, compared to that of the non-treated samples. Effect of temperature and pH on the biofilm formation in the presence of Se NPs and SeO2 was also evaluated. PMID:25175509

  4. Selenium-ligated palladium(II) complexes as highly active catalysts for carbon-carbon coupling reactions: the Heck reaction.

    PubMed

    Yao, Qingwei; Kinney, Elizabeth P; Zheng, Chong

    2004-08-19

    Three selenium-ligated Pd(II) complexes were readily synthesized and shown to be extremely active catalysts for the Heck reaction of various aryl bromides, including deactivated and heterocyclic ones. The catalytic activity of the selenide-based Pd(II) complexes not only rivals but vastly outperforms that of the corresponding phosphorus and sulfur analogues. Practical advantages of the selenium-based catalysts include their straightforward synthesis and high activity in the absence of any additives as well as the enhanced stability of the selenide ligands toward air oxidation. PMID:15330667

  5. Selenium speciation in tea by dispersive liquid-liquid microextraction coupled to high-performance liquid chromatography after derivatization with 2,3-diaminonaphthalene.

    PubMed

    Zhou, Qingxiang; Lei, Man; Li, Jing; Wang, Mengyun; Zhao, Danchen; Xing, An; Zhao, Kuifu

    2015-05-01

    Selenium is an important element for human health, and it is present in many natural drinks and foods. Present study described a new method using dispersive liquid-liquid microextraction prior to high-performance liquid chromatography with a UV variable wavelength detector for the determination of the total selenium, Se(IV), Se(VI), and total organoselenium in tea samples. In the procedure, 2,3-diaminonaphthalene was used as the chelating reagent, 400 μL acetonitrile was used as the disperser solvent and 60 μL chlorobenzene was used as the extraction solvent. The complex of Se(IV) and 2,3-diaminonaphthalene in the final extracted phase was analyzed by high-performance liquid chromatography. The factors influencing the derivatization and microextraction were investigated. Under the optimal conditions, the limit of detection was 0.11 μg/L for Se(IV) and the linearity range was in the range of 0.5-40 μg/L. This method was successfully applied to the determination of selenium in four tea samples with spiked recoveries ranging from 91.3 to 100%. PMID:25677605

  6. Catalysis-dependent selenium incorporation and migration in the nitrogenase active site iron-molybdenum cofactor

    PubMed Central

    Spatzal, Thomas; Perez, Kathryn A; Howard, James B; Rees, Douglas C

    2015-01-01

    Dinitrogen reduction in the biological nitrogen cycle is catalyzed by nitrogenase, a two-component metalloenzyme. Understanding of the transformation of the inert resting state of the active site FeMo-cofactor into an activated state capable of reducing dinitrogen remains elusive. Here we report the catalysis dependent, site-selective incorporation of selenium into the FeMo-cofactor from selenocyanate as a newly identified substrate and inhibitor. The 1.60 Å resolution structure reveals selenium occupying the S2B site of FeMo-cofactor in the Azotobacter vinelandii MoFe-protein, a position that was recently identified as the CO-binding site. The Se2B-labeled enzyme retains substrate reduction activity and marks the starting point for a crystallographic pulse-chase experiment of the active site during turnover. Through a series of crystal structures obtained at resolutions of 1.32–1.66 Å, including the CO-inhibited form of Av1-Se2B, the exchangeability of all three belt-sulfur sites is demonstrated, providing direct insights into unforeseen rearrangements of the metal center during catalysis. DOI: http://dx.doi.org/10.7554/eLife.11620.001 PMID:26673079

  7. Antitumor activity of hyaluronic acid-selenium nanoparticles in Heps tumor mice models.

    PubMed

    Ren, Yuena; Zhao, Ting; Mao, Guanghua; Zhang, Min; Li, Fang; Zou, Ye; Yang, Liuqing; Wu, Xiangyang

    2013-06-01

    In this study, hyaluronic acid-selenium (HA-Se) nanoparticles as novel complexes were synthesized and their antitumor activities in vivo were investigated. The mice inoculated with Heps tumor were orally administered with HA-Se nanoparticles at 86.45 mg/kg (H) and 4.32 mg/kg (L) body weights as high and low doses respectively (2.20% selenium content in the HA-Se nanoparticles samples by ICP-AES) for 10 days. The transmission electron microscopy (TEM) results indicated that the HA-Se nanoparticles were spherical with mean size of 50-70 nm. The HA-Se nanoparticles could significantly reduce tumor weights at the tumor inhibition ratios of 46.92% (H) and 49.12% (L) respectively. However, in the 5-fluorouracil positive group (25 mg/kg), the tumor inhibition ratio was 61.71%. From the study, the HA-Se nanoparticles (4.32 mg/kg) significantly increased thymus and spleen relative weights, enhanced the activities of superoxide dismutase (SOD), reduced the formation of malondialdehyde (MDA) and the activities of aspartate transaminase, alanine transaminase and crea in Heps tumor mice. The results of the study indicated that the HA-Se nanoparticles are potential antitumor candidate for cancer treatment. PMID:23500433

  8. Sequential photocatalyst-assisted digestion and vapor generation device coupled with anion exchange chromatography and inductively coupled plasma mass spectrometry for speciation analysis of selenium species in biological samples.

    PubMed

    Tsai, Yun-ni; Lin, Cheng-hsing; Hsu, I-hsiang; Sun, Yuh-chang

    2014-01-01

    We have developed an on-line sequential photocatalyst-assisted digestion and vaporization device (SPADVD), which operates through the nano-TiO2-catalyzed photo-oxidation and reduction of selenium (Se) species, for coupling between anion exchange chromatography (LC) and inductively coupled plasma mass spectrometry (ICP-MS) systems to provide a simple and sensitive hyphenated method for the speciation analysis of Se species without the need for conventional chemical digestion and vaporization techniques. Because our proposed on-line SPADVD allows both organic and inorganic Se species in the column effluent to be converted on-line into volatile Se products, which are then measured directly through ICP-MS, the complexity of the procedure and the probability of contamination arising from the use of additional chemicals are both low. Under the optimized conditions for SPADVD - using 1g of nano-TiO2 per liter, at pH 3, and illuminating for 80 s - we found that Se(IV), Se(VI), and selenomethionine (SeMet) were all converted quantitatively into volatile Se products. In addition, because the digestion and vaporization efficiencies of all the tested selenicals were improved when using our proposed on-line LC/SPADVD/ICP-MS system, the detection limits for Se(IV), Se(VI), and SeMet were all in the nanogram-per-liter range (based on 3σ). A series of validation experiments - analysis of neat and spiked extracted samples - indicated that our proposed methods could be applied satisfactorily to the speciation analysis of organic and inorganic Se species in the extracts of Se-enriched supplements. PMID:24331052

  9. Antioxidant and Hepatoprotective Activities of Mycelia Selenium Polysaccharide by Hypsizigus marmoreus SK-02.

    PubMed

    Liu, Min; Meng, Guangyuan; Zhang, Jianjun; Zhao, Huajie; Jia, Le

    2016-08-01

    This work was designed to investigate the characteristic properties (bond types and monosaccharide compositions), and hepatoprotective effects on carbon tetrachloride (CCl4)-induced liver damage of mycelia selenium polysaccharides (MSPS) separated and purified from Hypsizigus marmoreus SK-02. Characteristic analysis of MSPS showed the selenium content (70.15 μg/g) in mycelia. The antioxidant activities in vitro demonstrated that MSPS had potential effects on scavenging reactive oxygen species and enhancing the reducing power. The treatment of MSPS for CCl4-induced animal experiment demonstrated that the MSPS could reduce the levels of malondiadehyde (MDA), lipid peroxide (LPO), glutamic oxalacetic transaminase (AST), and glutamic-pyruvic transaminase (ALT) activities and improve the levels of glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), total cholesterol (TC), and triglyceride (TG) in serum/liver homogenate against CCl4-induced injures. Findings presented in this study clearly demonstrated that MSPS might be suitable for functional foods and natural drugs in preventing the CCl4-induced acute liver damage. PMID:26743865

  10. The speciation of marine particulate iron adjacent to active and passive continental margins

    NASA Astrophysics Data System (ADS)

    Lam, Phoebe J.; Ohnemus, Daniel C.; Marcus, Matthew A.

    2012-03-01

    We use synchrotron-based chemical-species mapping techniques to compare the speciation of suspended (1-51 μm) marine particulate iron collected in two open ocean environments adjacent to active and passive continental margins. Chemical-species mapping provides speciation information for heterogeneous environmental samples, and is especially good for detecting spectroscopically distinct trace minerals and species that could not be detectable by other methods. The average oxidation state of marine particulate iron determined by chemical-species mapping is comparable to that determined by standard bulk X-ray Absorption Near Edge Structure spectroscopy. Using chemical-species mapping, we find that up to 43% of particulate Fe in the Northwest Pacific at the depth of the adjacent active continental margin is in the Fe(II) state, with the balance Fe(III). In contrast, particulate iron in the eastern tropical North Atlantic, which receives the highest dust deposition on Earth and is adjacent to a passive margin, is dominated by weathered and oxidized Fe compounds, with Fe(III) contributing 90% of total iron. The balance is composed primarily of Fe(II)-containing species, but we detected individual pyrite particles in some samples within an oxygen minimum zone in the upper thermocline. Several lines of evidence point to the adjacent Mauritanian continental shelf as the source of pyrite to the water column. The speciation of suspended marine particulate iron reflects the mineralogy of iron from the adjacent continental margins. Since the solubility of particulate iron has been shown to be a function of its speciation, this may have implications for the bioavailability of particulate iron adjacent to passive compared to active continental margins.

  11. Quantification, localization, and speciation of selenium in seeds of canola and two mustard species compared to seed-meals produced by hydraulic press.

    PubMed

    Bañuelos, Gary S; Walse, Spencer S; Yang, Soo In; Pickering, Ingrid J; Fakra, Sirine C; Marcus, Matthew A; Freeman, John L

    2012-07-17

    Brassica plants accumulate selenium (Se) especially in seeds when grown in soils laden with Se. We report a chemical analysis of Se in Brassica seeds (canola, Indian mustard, and white mustard) and in their hydraulically pressed seed meals, which are used as a Se supplement in livestock animal feeds. Complementary techniques were used to measure total Se concentrations, to map the localization of Se, and to quantify different Se forms. Seeds and hydraulically pressed seed meals contained an average of 1.8 and 2.0 μg Se g(-1) DW, respectively. Selenium was primarily located in cotyledons and roots of seed embryos. Microfocused Se K-edge XANES and bulk XANES showed that seeds contained 90% of Se as C-Se-C forms. Hydraulically pressing seeds for oil caused changes in the forms of Se as follows: 40-55% C-Se-C forms, 33-42% selenocystine, 5-12% selenocysteine, and 11-14% trimethylselenonium ion. Aqueous extracts of seed and seed meals were also analyzed by SAX-HPLC/ICPMS and found to contain mainly the C-Se-C form SeMet, but also another C-Se-C form MeSeCys, which is of dietary pharmacological interest for cancer inhibition. In addition, SAX-HPLC/ICPMS also detected selenocystine and selenocysteine, further confirming the results obtained by XANES analyses. PMID:22747111

  12. 45S5Bioglass®-based scaffolds coated with selenium nanoparticles or with poly(lactide-co-glycolide)/selenium particles: Processing, evaluation and antibacterial activity.

    PubMed

    Stevanović, Magdalena; Filipović, Nenad; Djurdjević, Jelena; Lukić, Miodrag; Milenković, Marina; Boccaccini, Aldo

    2015-08-01

    In the bone tissue engineering field, there is a growing interest in the application of bioactive glass scaffolds (45S5Bioglass(®)) due to their bone bonding ability, osteoconductivity and osteoinductivity. However, such scaffolds still lack some of the required functionalities to enable the successful formation of new bone, e.g. effective antibacterial properties. A large number of studies suggest that selenium (Se) has significant role in antioxidant protection, enhanced immune surveillance and modulation of cell proliferation. Selenium nanoparticles (SeNp) have also been reported to possess antibacterial as well as antiviral activities. In this investigation, uniform, stable, amorphous SeNp have been synthesized and additionally immobilized within spherical PLGA particles (PLGA/SeNp). These particles were used to coat bioactive glass-based scaffolds synthesized by the foam replica method. Samples were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and transmission electron microscopy (TEM). SeNp, 45S5Bioglass(®)/SeNp and 45S5Bioglass(®)/PLGA/SeNp showed a considerable antibacterial activity against Gram positive bacteria, Staphylococcus aureus and Staphylococcus epidermidis, one of the main causative agents of orthopedic infections. The functionalized Se-coated bioactive glass scaffolds represent a new family of bioactive, antibacterial scaffolds for bone tissue engineering applications. PMID:26047884

  13. Geographic dialects in blind mole rats: role of vocal communication in active speciation.

    PubMed Central

    Nevo, E; Heth, G; Beiles, A; Frankenberg, E

    1987-01-01

    We compared and contrasted the physical structure of male "courtship" calls of 59 subterranean mole rats belonging to the Spalax ehrenbergi superspecies in Israel, comprising 11 populations of four chromosomal species (2N = 52, 54, 58, and 60). We also conducted behavioral auditory discrimination tests of 144 females of the four species in the laboratory. The results indicate that each chromosomal species has a vocal dialect significantly different from all others, although the call of 2N = 60, the last derivative of speciation, is not yet fully differentiated. Females of 2N = 52, 54, and 58 preferred their homospecific mates' calls, whereas females of 2N = 60 did not. We conclude that call differentiation builds up gradually and provides an efficient ethological reproductive premating isolation mechanism between the emerging species in the active speciation of mole rats in Israel. PMID:3472211

  14. Mercury speciation in the Mt. Amiata mining district (Italy): interplay between urban activities and mercury contamination

    USGS Publications Warehouse

    Rimondi, Valentina; Bardelli, Fabrizio; Benvenuti, Marco; Costagliola, Pilario; Gray, John E.; Lattanzi, Pierfranco

    2014-01-01

    A fundamental step to evaluate the biogeochemical and eco-toxicological significance of Hg dispersion in the environment is to determine speciation of Hg in solid matrices. In this study, several analytical techniques such as scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS), sequential chemical extractions (SCEs), and X-ray absorption spectroscopy (XANES) were used to identify Hg compounds and Hg speciation in samples collected from the Mt. Amiata Hg mining district, southern Tuscany, Italy. Different geological materials, such as mine waste calcine (retorted ore), soil, stream sediment, and stream water suspended particulate matter were analyzed. Results show that the samples were generally composed of highly insoluble Hg compounds such as sulphides (HgS, cinnabar and metacinnabar), and more soluble Hg halides such as those associated with the mosesite group. Other moderately soluble Hg compounds, HgCl2, HgO and Hg0, were also identified in stream sediments draining the mining area. The presence of these minerals suggests active and continuous runoff of soluble Hg compounds from calcines, where such Hg compounds form during retorting, or later in secondary processes. Specifically, we suggest that, due to the proximity of Hg mines to the urban center of Abbadia San Salvatore, the influence of other anthropogenic activities was a key factor for Hg speciation, resulting in the formation of unusual Hg-minerals such as mosesite.

  15. The selenium-75-homocholic acid taurine test reevaluated: combined measurement of fecal selenium-75 activity and 3 alpha-hydroxy bile acids in 211 patients

    SciTech Connect

    van Tilburg, A.J.; de Rooij, F.W.; van den Berg, J.W.; Kooij, P.P.; van Blankenstein, M. )

    1991-06-01

    The recommended reference values for the selenium-75-homocholic acid taurine (75SeHCAT) test, used in the analysis of chronic diarrhea, were evaluated in 211 patients by comparing simultaneous measurements of 3 alpha-hydroxy bile acids and 75Se activity in daily collected stools. An initial evaluation in 11 patients showed that the fecal collection method, which allows inspection and additional analysis of stools, was equivalent to the abdominal retention method. Selenium-75-HCAT whole-body retention half-life (WBR50) was greater than 2.8 days in less than 10% of the patients with bile acid malabsorption and less than 1.7 days in less than 10% of the normals. We recommend that a 75SeHCAT WBR50 less than 1.7 days is abnormal, a WBR50 greater than 2.8 days is normal, and a WBR50 in the range 1.7-2.8 days is equivocal, which was the case in 48% (94/195) of the patients in this study.

  16. Study of the effect of sample preparation and cooking on the selenium speciation of selenized potatoes by HPLC with ICP-MS and electrospray ionization MS/MS.

    PubMed

    Infante, Heidi Goenaga; Borrego, Ana Arias; Peachey, Emma; Hearn, Ruth; O'Connor, Gavin; Barrera, Tamara García; Ariza, José Luis Gómez

    2009-01-14

    The efficiency of enzymatic hydrolysis and leaching with water using accelerated solvent extraction (ASE) or boiling was investigated for quantitative Se speciation in selenized potatoes using reversed phase HPLC coupled to ICP-MS. Preliminary identification of selenomethionine (SeMet), Se-methylselenocysteine (SeMeCys), and selenate in extracts of potato skin and flesh was achieved using complementary reversed phase and anion-exchange HPLC-ICP-MS and retention time matching with standards. The quantitative speciation data revealed a higher percentage of selenomethionine (73% of the total Se) found in the flesh in comparison with skin (containing 21% of the total Se as SeMet). ASE and boiling in water were found to be similar in terms of Se extraction efficiency and profiles. However, ASE was found to be more efficient than boiling with respect to sample cleanup and reduced sample handling. The presence of SeMet at parts per billion levels in selenized potatoes was confirmed by reversed phase HPLC with online ESI MS/MS. PMID:19093878

  17. Bhas 42 cell transformation activity of cigarette smoke condensate is modulated by selenium and arsenic.

    PubMed

    Han, Sung Gu; Pant, Kamala; Bruce, Shannon W; Gairola, C Gary

    2016-04-01

    Cigarette smoking remains a major health risk worldwide. Development of newer tobacco products requires the use of quantitative toxicological assays. Recently, v-Ha-ras transfected BALB/c3T3 (Bhas 42) cell transformation assay was established that simulates the two-stage animal tumorigenesis model and measures tumor initiating and promoting activities of chemicals. The present study was performed to assess the feasibility of using this Bhas 42 cell transformation assay to determine the initiation and promotion activities of cigarette smoke condensate (CSC) and its water soluble fraction. Further, the modulating effects of selenium and arsenic on cigarette smoke-induced cell transformation were investigated. Dimethyl sulfoxide (DMSO) and water extracts of CSC (CSC-D and CSC-W, respectively) were tested at concentrations of 2.5-40 µg mL(-1) in the initiation or promotion assay formats. Initiation protocol of the Bhas 42 assay showed a 3.5-fold increase in transformed foci at 40 µg mL(-1) of CSC-D but not CSC-W. The promotion phase of the assay yielded a robust dose response with CSC-D (2.5-40 µg mL(-1)) and CSC-W (20-40 µg mL(-1)). Preincubation of cells with selenium (100 nM) significantly reduced CSC-induced increase in cell transformation in initiation assay. Co-treatment of cells with a sub-toxic dose of arsenic significantly enhanced cell transformation activity of CSC-D in promotion assay. The results suggest a presence of both water soluble and insoluble tumor promoters in CSC, a role of oxidative stress in CSC-induced cell transformation, and usefulness of Bhas 42 cell transformation assay in comparing tobacco product toxicities and in studying the mechanisms of tobacco carcinogenesis. PMID:26924598

  18. Selenium dependent glutathione-peroxidase (GSH-Px) activity in the retina of preterm human infants

    SciTech Connect

    Lane, H.; Hittner, H.; Barron, S.; Mehta, R.; Kretzer, F.

    1986-03-01

    GSH-Px activity was determined in the retina of 15 preterm human neonates with gestational ages of 17-28 weeks and birth weights of 120 to 960 g. GSH-Px activity was measured using the coupled assay. The infants survived from 0.5 to 9 hours after parturition. The retinas were removed within 3 hours of autopsy. Through electronmicroscopy, there was verification that the entire retina was removed and no contamination of other eye tissues occurred. After removal, the retinas were immediately dissolved in phosphate buffered pH 7.0 saline for assay of GSH-Px activity. The mean GSH-Px activity was 19.44 +/- 6.44 with a range of 11.1 to 32.8 units NAPH/sub 2/ oxidized/min/g protein. There was a negative correlation between birth weight and GSH-Px activity (r = -0.86) and between week of gestation and GSH-Px activity (r = -0.91). The neonatal retina GSH-Px activity was 2 to 15 times higher than found in adult retinas. Thus, this research demonstrates that selenium dependent GSH-Px activity is elevated in the preterm neonate's retina which indicates that retina GSH-Px activity may be an important antioxidation system in the premature neonate.

  19. Speciation of selenium in environmental samples by solid-phase spectrophotometry using 2,3-dichloro-6-(2,7-dihydroxy-naphthylazo)quinoxaline.

    PubMed

    Amin, Alaa S

    2014-01-01

    Solid-phase spectrophotometry was applied to determination of trace amounts of selenium (Se) in water, soil, plant materials, human hair, and a cosmetic preparation (lipstick). Se(IV) was sorbed in a dextran type lipophilic gel as a complex with 2,3-dichloro-6-(2,7-dihydroxy-naphthylazo)quinoxaline (DCDHNAQ), whereas Se(VI) was determined after boiling in HCI for 10 min to convert Se(VI) to Se(IV). Resin phase absorbances at 588 and 800 nm were measured directly, which allowed the determination of Se in the range of 0.2-3.3 microg/L with an RSD of 1.22%. The influences of analytical parameters including pH of the aqueous solution, amounts of DCDHNAQ, and sample volume were investigated. The molar absorptivities were found to be 1.09 x 10(6), 4.60 x 10(6), and 1.23 x 10(7) L/mol cm for 100, 500, and 1000 mL, respectively. The LOD and LOQ of the 500 mL sample method were 110 and 360 ng/L, respectively, when using 50 mg dextran type lipophilic gel. For a 1000 mL sample, the LOD and LOQ were 60 and 200 ng/L, respectively, using 50 mg of the exchanger. Increasing the sample volume enhanced the sensitivity. No considerable interferences were observed from other investigated anions and cations on the Se determination. PMID:24830171

  20. Bioaccumulation and speciation of selenium in fish and insects collected from a mountaintop removal coal mining-impacted stream in West Virginia.

    PubMed

    Arnold, M C; Lindberg, T Ty; Liu, Y T; Porter, K A; Hsu-Kim, H; Hinton, D E; Di Giulio, R T

    2014-07-01

    A major contaminant of concern for mountaintop removal/valley fill (MTR/VF) coal mining is selenium (Se), an essential micronutrient that can be toxic to fish. Creek chubs (Semotilus atromaculatus), green sunfish (Lepomis cyanellus), and composite insect samples were collected in March-July, 2011-2013 at two sites within the Mud River, West Virginia. One site (MR7) receives MTR/VF coal mining effluent, while the reference site (LFMR) does not. MR7 water had significantly higher concentrations of soluble Se (p < 0.01) and conductivity (p < 0.005) compared to LFMR. MR7 whole insects contained significantly higher concentrations of Se compared to LFMR insects (p < 0.001). MR7 creek chubs had significantly higher Se in fillets, liver, and ovary tissues compared to LFMR samples (p < 0.0001, p < 0.0001, and p < 0.02, respectively). MR7 green sunfish fillets contained significantly higher Se (p < 0.0001). Histological examination showed LFMR creek chub gills contained a typical amount of parasitic infestations; however MR7 gills contained minimal to no visible parasites. X-ray absorption spectroscopic analyses revealed that MR7 whole insects and creek chub tissues primarily contained organic Se and selenite. These two species of Mud River fish were shown to specifically accumulate Se differently in tissues compartments. Tissue-specific concentrations of Se may be useful in determining potential reproductive consequences of Se exposure in wild fish populations. PMID:24723096

  1. Selenium inhibits Staphylococcus aureus-induced inflammation by suppressing the activation of the NF-κB and MAPK signalling pathways in RAW264.7 macrophages.

    PubMed

    Bi, Chong-Liang; Wang, Heng; Wang, Yin-Jie; Sun, Jun; Dong, Jun-Sheng; Meng, Xia; Li, Jian-Ji

    2016-06-01

    Inflammation is the hallmark of Staphylococcus aureus (S. aureus)-induced mastitis. Given the interesting relationship between selenium levels and inflammation, this study aimed to demonstrate that selenium modulated the inflammation reaction by suppressing the nuclear factor kappa B (NF-κB) and mitogen activated protein kinase (MAPK) signalling pathways. RAW264.7 macrophages were treated with three different concentrations (1μmol/l, 1.5μmol/l, and 2μmol/l) of Na2SeO3 for 12h before infection with S. aureus for 6h, 8h, and 10h. The results showed that selenium significantly reduced the mRNA expression levels of tumour necrosis factor-alpha (TNF-α), interleukin-1 beta (IL-1β), and interleukin-6 (IL-6). Furthermore, the release of TNF-α, IL-1β, and IL-6 was decreased significantly with selenium supplementation. In addition, selenium influenced the NF-κB signalling pathway by suppressing the activation of NF-κB p65 and degradation of inhibitory kappa-B (IκB). Selenium also suppressed extracellular regulated protein kinase (Erk), c-Jun N-terminal kinase (Jnk), and p38 phosphorylation through the MAPK signalling pathway. In conclusion, selenium played an anti-inflammation role in RAW264.7 macrophages infected with S. aureus by suppressing the activation of the NF-κB and MAPK signalling pathways. PMID:27036486

  2. Determination and speciation of trace and ultratrace selenium ions by energy-dispersive X-ray fluorescence spectrometry using graphene as solid adsorbent in dispersive micro-solid phase extraction.

    PubMed

    Kocot, Karina; Leardi, Riccardo; Walczak, Beata; Sitko, Rafal

    2015-03-01

    A dispersive micro-solid phase extraction (DMSPE) with graphene as a solid adsorbent and ammonium pyrrolidinedithiocarbamate (APDC) as a chelating agent was proposed for speciation and detemination of inorganic selenium by the energy-dispersive X-ray fluorescence spectrometry (EDXRF). In developed DMSPE, graphene particles are dispersed throughout the analyzed solution, therefore reaction between Se(IV)-APDC complexes and graphene nanoparticles occurs immediately. The concentration of Se(VI) is calculated as the difference between the concentration of selenite after and before prereduction of selenate. A central composite face-centered design with 3 center points was performed in order to optimize conditions and to study the effect of four variables (pH of the sample, concentration of APDC, concentration of Triton-X-100, and sample volume). The best results were obtained when suspension consisting of 200 µg of graphene nanosheets, 1.2 mg of APDC and 0.06 mg of Triton-X-100 was rapidly injected to the 50 mL of the analyzed solution. Under optimized conditions Se ions can be determined with a very good recovery (97.7±5.0% and 99.2±6.6% for Se(IV) and Se(VI), respectively) and precision (RSD=5.1-6.6%). Proposed DMSPE/EDXRF procedure allowed to obtain low detection limits (0.032 ng mL(-1)) and high enrichment factor (1013±15). The proposed methodology was successfully applied for the determination of Se in mineral, tap, lake and sea water samples as well as in biological materials (Lobster Hepatopancreas and Pig Kidney). PMID:25618680

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

    SciTech Connect

    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 up 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.

  4. Anti-hyperglycemic activity of selenium nanoparticles in streptozotocin-induced diabetic rats

    PubMed Central

    Al-Quraishy, Saleh; Dkhil, Mohamed A; Abdel Moneim, Ahmed Esmat

    2015-01-01

    The study was designed to investigate the anti-hyperglycemic activity of selenium nanoparticles (SeNPs) in streptozotocin-induced diabetic rats. Fifty-five mg/kg of streptozotocin was injected in rats to induce diabetes. Animals either treated with SeNPs alone or with insulin (6 U/kg) showed significantly decreased fasting blood glucose levels after 28 days of treatment. The serum insulin concentration in untreated diabetic animals was also enhanced by SeNPs. The results demonstrated that SeNPs could significantly decrease hepatic and renal function markers, total lipid, total cholesterol, triglyceride and low-density lipoprotein cholesterol levels, and glucose-6-phosphatase activity. At the same time, SeNPs increased malic enzyme, hexokinase and glucose-6-phosphate dehydrogenase activity, liver and kidney glycogen contents, and high-density lipoprotein cholesterol levels. In addition, SeNPs were able to prevent the histological injury in the hepatic and renal tissues of rats. However, insulin injection also exhibited a significant improvement in diabetic animals after 28 days of treatment. This study suggests that SeNPs can alleviate hyperglycemia and hyperlipidemia in streptozotocin-induced diabetic rats, possibly by eliciting insulin-mimetic activity. PMID:26604749

  5. 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. PMID:26637493

  6. Selenium: metabolism and endocrines (Minireview).

    PubMed

    Brtkova; Brtko

    1996-09-01

    Selenium occurs both in prokaryocytes and eukaryocytes as a component of selenoenzymes or selenoproteins. Approximately 80 % of selenium in animal or human body occurs in the form of seleno-L-cysteine, an amino acid encoded by one of standard termination codons. Selenium is an integral component of the active site of glutathione peroxidases which plays an important role in the antioxidant system. Iodothyronine 5-deiodinase, type I is also a selenoenzyme consisting of two identical subunits which catalyzes a reductive monodeiodination of iodothyronine residues of the phenolic ring. General characteristics of several selenoproteins and selenium binding proteins are summarized, also certain facts on the effects of selenium deficiency in man and its distribution and toxicity in higher organisms, are reviewed. Selenium status in the population from selected regions in Slovakia is reported and compared with that in other countries. PMID:10979042

  7. Lipid peroxidation, proteins modifications, anti-oxidant enzymes activities and selenium deficiency in the plasma of hashitoxicosis patients

    PubMed Central

    Mseddi, Malek; Ben Mansour, Riadh; Mnif, Fatma; Gargouri, Bochra; Abid, Mohamed; Guermazi, Fadhel; Attia, Hamadi; Lassoued, Saloua

    2015-01-01

    Objectives: The aim of this study was to explore the oxidative stress profile in hashitoxicosis (HTX) and to compare it with that of healthy subjects. Patients and methods: Spectrophotometric methods were used to evaluate the oxidative stress markers. The selenium level was investigated by atomic absorption. Results: High levels of thiobarbituric acid reactive species (TBARS) and conjugated dienes were found in HTX patients (p = 0.034 and p = 0.043, respectively) compared with healthy controls. For antioxidant enzymes, superoxide dismutase (SOD) and catalase activities increased, whereas that of glutathione peroxidase (GPx) decreased (p = 0.000, p = 0.014, p = 0.000, respectively) compared with controls. A reduction in the level of selenium (p = 0.029) and thiol groups (p = 0.008) were shown in patients; however, levels of carbonyl group and malondialdehyde (MDA) protein adducts decreased (p = 0.000) compared with controls. Positive correlation was shown between levels of free thyroxine (FT4) and TBARS (r = 0.711, p = 0.048) and between FT4 level and SOD activity (r = 0.713, p = 0.047). Conversely, GPx activity presented a negative correlation with FT4 and free triiodothyronine (FT3) levels (r = –0.934, p = 0.001; r = –0.993, p = 0.000, respectively). In addition, GPx activity showed positive correlation with selenium level (r = 0.981, p = 0.019) and the FT3 level correlated negatively with the level of thiol groups (r = –0.892, p = 0.017). Conclusions: This study shows the presence of an oxidative stress and selenium deficiency in HTX patients and suggests that the hyperthyroid state is strongly implicated in the establishment of this disturbed oxidative profile. PMID:26445640

  8. Selenium Deficiency Attenuates Chicken Duodenal Mucosal Immunity via Activation of the NF-κb Signaling Pathway.

    PubMed

    Liu, Zhe; Qu, Yanpeng; Wang, Jianfa; Wu, Rui

    2016-08-01

    Selenium (Se) deficiency can cause intestinal mucosal inflammation, which is related to activation of nuclear transcription factor kappa-B (NF-κB) signaling pathway. However, the mechanism of inflammatory response in chicken duodenal mucosa caused by Se deficiency and its relationship with the NF-κB signaling pathway remain elusive. In this study, we firstly obtained Se-deficient chickens bred with 0.01 mg/kg Se and the normal chickens bred with 0.4 mg/kg Se for 35 days. Then, NF-κB signaling pathway, secretory immunoglobulin A (SIgA), inflammatory cytokines, oxidized glutathione, glutathione peroxidase, and glutathione activities were determined. The results showed that Se deficiency obviously enhanced p50, p65, and p65 DNA-binding activities. The phosphorylation of IκB-α and phosphorylation of kappa-B kinase subunit alpha (IKKα) and IKKα were elevated, but IκB-α was decreased (P < 0.05). Moreover, Se deficiency reduced SIgA amount in the duodenal mucosa but increased the level of interleukin-1β (IL-1β), IL-17A, tumor necrosis factor-α (TNF-α), and interferon gamma (IFN-γ). In contrast, anti-inflammatory cytokines, such as TGF-β1 and IL-10, were significantly suppressed. Additionally, Se deficiency increased oxidized glutathione activity, whereas decreased glutathione peroxidase and glutathione activities (P < 0.05), suggesting that Se deficiency affected the regulation function of redox. Taken together, our results demonstrated that Se deficiency attenuated chicken duodenal mucosal immunity via activation of NF-κB signaling pathway regulated by redox activity, which suggested that Se is a crucial host factor involved in regulating inflammation. PMID:26728795

  9. Selenium Sulfide

    MedlinePlus

    Selenium sulfide comes in a lotion and is usually applied as a shampoo. As a shampoo, selenium sulfide usually is used twice a week for the first ... it is irritating. Rinse off all of the lotion.Do not use this medication on children younger ...

  10. Construction of selenium nanoparticles/β-glucan composites for enhancement of the antitumor activity.

    PubMed

    Jia, Xuewei; Liu, Qingye; Zou, Siwei; Xu, Xiaojuan; Zhang, Lina

    2015-03-01

    We report on a green procedure for the stabilization of selenium nanoparticles (SeNPs) by a naturally occurring β-glucan with triple helical conformation known as Lentinan (t-LNT) in water after denaturing into single chains (s-LNT) at 140 °C. The results demonstrated that the s-LNT can interact with SeNPs through Se-O-H interaction. Transmission electron microscopy (TEM), energy dispersive X-ray (EDX) spectra, UV/vis, X-ray diffraction (XRD) and dynamic light scattering (DLS) showed that s-LNT coated SeNPs to form a stable nano-composite Se/s-LNT, leading to good dispersion of SeNPs. Especially, the as-prepared Se/s-LNT composite in the solution could remain homogeneous and translucent for 30 days without any precipitates. Different size distribution of SeNPs was prepared by simply controlling the concentrations of selenite sodium and the corresponding reducing agent ascorbic acid. The size effect of SeNPs on anti-tumor activity was revealed that the SeNPs with more evenly particle size distribution show the higher anticancer activity. PMID:25498656

  11. Synthesis, characterization, antioxidant activity and neuroprotective effects of selenium polysaccharide from Radix hedysari.

    PubMed

    Wei, Dongfeng; Chen, Tong; Yan, Mingfei; Zhao, Wanghong; Li, Fei; Cheng, Weidong; Yuan, Lixia

    2015-07-10

    Beta-amyloid (Aβ) peptide, the hallmark of Alzheimer's disease, invokes oxidative damage to neurons and eventually leads to neuronal death. Selenylation modification of polysaccharide obtained from Radix hedysari (RHP) was studied to access antioxidant activities and neuroprotective effects against oxidative stress and apoptosis induced by Aβ25-35 in vitro. A series of the selenylation derivatives of RHP (Se-RHP) was synthesized using nitric acid-sodium selenite (HNO3-Na2SeO3) method. The organic selenium content of Se-RHP increased from 1.04 to 3.29 mg/g. However, compared with the weight-average molecular mass (Mw) of RHP, Mw of Se-RHP showed a significant decrease, and varied from 27.7 kDa to 62.7 kDa. FT-IR spectra and (13)C NMR spectra indicated the selenite groups had been introduced mainly at the C-6 positions of RHP. Compared with RHP, Se-RHP showed greater antioxidant activities in vitro. Furthermore, both RHP and Se-RHP3 had neuroprotective effects against Aβ25-35-induced oxidative stress and apoptosis in SH-SY5Y human neuroblastoma cells, which might be a potential therapeutic agent for preventing or treating neurodegenerative diseases. PMID:25857971

  12. Sewage sludge as a source of environmental selenium.

    PubMed

    Cappon, C J

    1991-03-01

    Information is presented on the impact of land application of municipal sewage sludge on the selenium content and speciation in soil, groundwater and edible vegetation. Sources and typical concentrations of selenium in sludge are documented. A discussion of selenium uptake by agricultural crops from sludge-amended soil includes results from greenhouse and field studies. A comparison is made with crop selenium uptake from fly ash application. The effect of sludge treatment on animal and human dietary selenium intake is quantitatively evaluated and selenium guidelines for sludge application are summarized. The conclusion is made that future widespread use of sludge on agricultural land will result in increased selenium uptake by food crops and human dietary intake. While this may not present an increased human health risk, long-term risks are identified and recommendations are made to minimize them. PMID:2063182

  13. Sulfur oxidation activities of pure and mixed thermophiles and sulfur speciation in bioleaching of chalcopyrite.

    PubMed

    Zhu, Wei; Xia, Jin-Lan; Yang, Yi; Nie, Zhen-yuan; Zheng, Lei; Ma, Chen-yan; Zhang, Rui-yong; Peng, An-an; Tang, Lu; Qiu, Guan-zhou

    2011-02-01

    The sulfur oxidation activities of four pure thermophilic archaea Acidianus brierleyi (JCM 8954), Metallosphaera sedula (YN 23), Acidianus manzaensis (YN 25) and Sulfolobus metallicus (YN 24) and their mixture in bioleaching chalcopyrite were compared. Meanwhile, the relevant surface sulfur speciation of chalcopyrite leached with the mixed thermophilic archaea was investigated. The results showed that the mixed culture, with contributing significantly to the raising of leaching rate and accelerating the formation of leaching products, may have a higher sulfur oxidation activity than the pure cultures, and jarosite was the main passivation component hindering the dissolution of chalcopyrite, while elemental sulfur seemed to have no influence on the dissolution of chalcopyrite. In addition, the present results supported the former speculation, i.e., covellite might be converted from chalcocite during the leaching experiments, and the elemental sulfur may partially be the derivation of covellite and chalcocite. PMID:21194927

  14. Design and feasibility of active matrix flat panel detector using avalanche amorphous selenium for protein crystallography.

    PubMed

    Sultana, Afrin; Reznik, Alla; Karim, Karim S; Rowlands, J A

    2008-10-01

    Protein crystallography is the most important technique for resolving the three-dimensional atomic structure of protein by measuring the intensity of its x-ray diffraction pattern. This work proposes a large area flat panel detector for protein crystallography based on direct conversion x-ray detection technique using avalanche amorphous selenium (a-Se) as the high gain photoconductor, and active matrix readout using amorphous silicon (a-Si:H) thin film transistors. The detector employs avalanche multiplication phenomenon of a-Se to make the detector sensitive to each incident x ray. The advantages of the proposed detector over the existing imaging plate and charge coupled device detectors are large area, high dynamic range coupled to single x-ray detection capability, fast readout, high spatial resolution, and inexpensive manufacturing process. The optimal detector design parameters (such as detector size, pixel size, and thickness of a-Se layer), and operating parameters (such as electric field across the a-Se layer) are determined based on the requirements for protein crystallography application. The performance of the detector is evaluated in terms of readout time (<1 s), dynamic range (approximately 10(5)), and sensitivity (approximately 1 x-ray photon), thus validating the detector's efficacy for protein crystallography. PMID:18975678

  15. Rice genomes recorded ancient pararetrovirus activities: Virus genealogy and multiple origins of endogenization during rice speciation.

    PubMed

    Chen, Sunlu; Liu, Ruifang; Koyanagi, Kanako O; Kishima, Yuji

    2014-12-01

    Viral fossils in rice genomes are a best entity to understand ancient pararetrovirus activities through host plant history because of our advanced knowledge of the genomes and evolutionary history with rice and its related species. Here, we explored organization, geographic origins and genealogy of rice pararetroviruses, which were turned into endogenous rice tungro bacilliform virus-like (eRTBVL) sequences. About 300 eRTBVL sequences from three representative rice genomes were clearly classified into six families. Most of the endogenization events of the eRTBVLs were initiated before differentiation of the rice progenitor (> 160,000 years ago). We successfully followed the genealogy of old relic viruses during rice speciation, and inferred the geographical origins for these viruses. Possible virus genomic sequences were explained mostly by recombinations between different virus families. Interestingly, we discovered that only a few recombination events among the numerous occasions had determined the virus genealogy. PMID:25461539

  16. Digital radiography using amorphous selenium: photoconductively activated switch (PAS) readout system.

    PubMed

    Reznik, Nikita; Komljenovic, Philip T; Germann, Stephen; Rowlands, John A

    2008-03-01

    A new amorphous selenium (a-Se) digital radiography detector is introduced. The proposed detector generates a charge image in the a-Se layer in a conventional manner, which is stored on electrode pixels at the surface of the a-Se layer. A novel method, called photoconductively activated switch (PAS), is used to read out the latent x-ray charge image. The PAS readout method uses lateral photoconduction at the a-Se surface which is a revolutionary modification of the bulk photoinduced discharge (PID) methods. The PAS method addresses and eliminates the fundamental weaknesses of the PID methods--long readout times and high readout noise--while maintaining the structural simplicity and high resolution for which PID optical readout systems are noted. The photoconduction properties of the a-Se surface were investigated and the geometrical design for the electrode pixels for a PAS radiography system was determined. This design was implemented in a single pixel PAS evaluation system. The results show that the PAS x-ray induced output charge signal was reproducible and depended linearly on the x-ray exposure in the diagnostic exposure range. Furthermore, the readout was reasonably rapid (10 ms for pixel discharge). The proposed detector allows readout of half a pixel row at a time (odd pixels followed by even pixels), thus permitting the readout of a complete image in 30 s for a 40 cm x 40 cm detector with the potential of reducing that time by using greater readout light intensity. This demonstrates that a-Se based x-ray detectors using photoconductively activated switches could form a basis for a practical integrated digital radiography system. PMID:18404939

  17. Digital radiography using amorphous selenium: Photoconductively activated switch (PAS) readout system

    SciTech Connect

    Reznik, Nikita; Komljenovic, Philip T.; Germann, Stephen; Rowlands, John A.

    2008-03-15

    A new amorphous selenium (a-Se) digital radiography detector is introduced. The proposed detector generates a charge image in the a-Se layer in a conventional manner, which is stored on electrode pixels at the surface of the a-Se layer. A novel method, called photoconductively activated switch (PAS), is used to read out the latent x-ray charge image. The PAS readout method uses lateral photoconduction at the a-Se surface which is a revolutionary modification of the bulk photoinduced discharge (PID) methods. The PAS method addresses and eliminates the fundamental weaknesses of the PID methods--long readout times and high readout noise--while maintaining the structural simplicity and high resolution for which PID optical readout systems are noted. The photoconduction properties of the a-Se surface were investigated and the geometrical design for the electrode pixels for a PAS radiography system was determined. This design was implemented in a single pixel PAS evaluation system. The results show that the PAS x-ray induced output charge signal was reproducible and depended linearly on the x-ray exposure in the diagnostic exposure range. Furthermore, the readout was reasonably rapid (10 ms for pixel discharge). The proposed detector allows readout of half a pixel row at a time (odd pixels followed by even pixels), thus permitting the readout of a complete image in 30 s for a 40 cmx40 cm detector with the potential of reducing that time by using greater readout light intensity. This demonstrates that a-Se based x-ray detectors using photoconductively activated switches could form a basis for a practical integrated digital radiography system.

  18. Glutathione peroxidase activity and chemical forms of selenium in tissues of rats given selenite or selenomethionine

    SciTech Connect

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

    1988-05-01

    Glutathione peroxidase (GPx) activity and deposition of selenium (Se) were examined in tissues of rats given dietary Se for 7 wk as either selenite or selenomethionine (SeMet) with 75Se radiotracer of the same chemical form. On the basis of Se:75Se ratio, all tissues of the rats fed selenite were equilibrated with the dietary source, but tissues of the SeMet fed animals maintained a ratio of Se:75Se greater than the dietary ratio. Deposition of dietary Se and 75Se was higher in most tissues of rats fed SeMet. Muscle 75Se was the largest single tissue pool of 75Se in both groups accounting for one-third of recovered 75Se in the rats fed selenite, and one-half of recovered 75Se in the rats fed SeMet. Tissue GPx activities were not different between the two dietary groups. The proportion of Se as GPx in tissues was highest in erythrocytes of the rats fed selenite (.81) and lowest in testes and epididymides of the rats fed SeMet (.009). The proportion of Se present in cytosolic GPx was consistently higher in tissues of rats fed selenite. Erythrocytes of the rats fed SeMet had more 75Se associated with hemoglobin, and muscle cytosols of the rats fed selenite had more 75Se associated with the G-protein. The proportion of 75Se as SeMet determined by ion exchange chromatography of tissue hydrolysates was higher in tissues of rats fed SeMet (highest in muscle and hemoglobin, 70%, and lowest in testes, 16%). In contrast, selenocysteine was the predominant form of Se present in tissues of rats given selenite. These results indicate that the form of Se administered will influence the form in the tissues, the percentage of Se with GPx and the body burden of Se.

  19. 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.

  20. Ptaquiloside reduces NK cell activities by enhancing metallothionein expression, which is prevented by selenium

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pteridium aquilinum, one of the most important poisonous plants in the world, is known to be carcinogenic to animals and humans. Moreover, our previous studies showed that the immunosuppressive effects of ptaquiloside, its main toxic agent, were prevented by selenium in mouse natural killer (NK) cel...

  1. Speciation and chemical activities in superheated sodium borate solutions. Final report

    SciTech Connect

    Weres, O.

    1993-06-01

    The system H{sub 2}O-B{sub 2}O{sub 3}-Na{sub 2}O has been studied experimentally at 277{degrees} and 317{degrees}C. The activities of water and boric acid have been determined at mole ratios Na/B from 0 to 1.5, and total dissolved solids 3 to 80 weight percent. The activity of boric acid has been fitted to within experimental error using a speciation model with eight complex species. This model is consistent with the model previously published by Mesmer et al. The electrolyte properties of the liquid are modelled using the Pitzer-Simonson Model of very concentrated electrolyte solutions. The calculated values of water activity agree with experiment, and the activity of NaOH and pOH have also been calculated. These data will allow prediction of the composition and chemical behavior of sodium borate liquids that may accumulate in the superheated crevices within a steam generator. A modified form of the model is provided for use with MULTEQ. The potassium borate system also was briefly studied at 317{degrees}C, and is adequately described by a model with five complex species. The potassium borate liquid is more alkaline at K/B = 1 than a sodium borate liquid at the same mole ratio, but pOH in the two systems is the same at lower mole ratios.

  2. Relationship between redox activity and chemical speciation of size-fractionated particulate matter

    PubMed Central

    Ntziachristos, Leonidas; Froines, John R; Cho, Arthur K; Sioutas, Constantinos

    2007-01-01

    Background Although the mechanisms of airborne particulate matter (PM) related health effects remain incompletely understood, one emerging hypothesis is that these adverse effects derive from oxidative stress, initiated by the formation of reactive oxygen species (ROS) within affected cells. Typically, ROS are formed in cells through the reduction of oxygen by biological reducing agents, with the catalytic assistance of electron transfer enzymes and redox active chemical species such as redox active organic chemicals and metals. The purpose of this study was to relate the electron transfer ability, or redox activity, of the PM samples to their content in polycyclic aromatic hydrocarbons and various inorganic species. The redox activity of the samples has been shown to correlate with the induction of the stress protein, hemeoxygenase-1. Results Size-fractionated (i.e. < 0.15; < 2.5 and 2.5 – 10 μm in diameter) ambient PM samples were collected from four different locations in the period from June 2003 to July 2005, and were chemically analyzed for elemental and organic carbon, ions, elements and trace metals and polycyclic aromatic hydrocarbons. The redox activity of the samples was evaluated by means of the dithiothreitol activity assay and was related to their chemical speciation by means of correlation analysis. Our analysis indicated a higher redox activity on a per PM mass basis for ultrafine (< 0.15 μm) particles compared to those of larger sizes. The PM redox activity was highly correlated with the organic carbon (OC) content of PM as well as the mass fractions of species such as polycyclic aromatic hydrocarbons (PAH), and selected metals. Conclusion The results of this work demonstrate the utility of the dithiothreitol assay for quantitatively assessing the redox potential of airborne particulate matter from a wide range of sources. Studies to characterize the redox activity of PM from various sources throughout the Los Angeles basin are currently

  3. Toxicity, bioavailability and metal speciation.

    PubMed

    Jonnalagadda, S B; Rao, P V

    1993-11-01

    1. Environmental toxicology emphasizes the difference from traditional toxicology in which pure compounds of interest are added to purified diets, or injected into the test animals. When the objective is to study the fate and effects of trace elements in the environment, knowledge of the speciation of the elements and their physico-chemical forms is important. 2. Cadmium salts such as the sulfides, carbonates or oxides, are practically insoluble in water. However, these can be converted to water-soluble salts in nature under the influence of oxygen and acids. Chronic exposure to Cd is associated with renal toxicity in humans once a critical body burden is reached. 3. The solubility of As(III) oxide in water is fairly low, but high in either acid or alkali. In water, arsenic is usually in the form of the arsenate or arsenite. As(III) is systemically more poisonous than the As(V), and As(V) is reduced to the As(III) form before exerting any toxic effects. Organic arsenicals also exert their toxic effects in vivo in animals by first metabolizing to the trivalent arsenoxide form. Some methyl arsenic compounds, such as di- and trimethylarsines, occur naturally as a consequence of biological activity. The toxic effect of arsenite can be potentiated by dithiols, while As has a protective effect against the toxicity of a variety of forms of Se in several species. 4. Selenium occurs in several oxidation states and many selenium analogues of organic sulfur compounds exist in nature. Selenium in selenate form occurs in alkaline soils, where it is soluble and easily available to plants. Selenite binds tightly to iron and aluminum oxides and thus is quite insoluble in soils. Hydrogen selenide is a very toxic gas at room temperature. The methylated forms of Se are much less toxic for the organism than selenite. However, the methylated Se derivatives have strong synergistic toxicity with other minerals such as arsenic. 5. Aquatic organisms absorb and retain Hg in the tissues, as

  4. Purification, characterization, and antioxidant activities of selenium-containing proteins and polysaccharides in royal sun mushroom, Agaricus brasiliensis (Higher Basidiomycetes).

    PubMed

    Mao, Guanghua; Feng, Weiwei; Xiao, Hui; Zhao, Ting; Li, Fang; Zou, Ye; Ren, Yuena; Zhu, Yang; Yang, Liuqing; Wu, Xiangyang

    2014-01-01

    The Agaricus brasiliensis proves to be the main source of many minerals, especially selenium (Se). In this study, Se-containing polysaccharides and proteins were isolated, purified, and characterized. The 1,1-diphenyl-2-picrylhydrazyl (DPPH) and hydroxyl radical scavenging activity of Se-containing proteins and polysaccharides were also studied. Selenium in A. brasiliensis is present mostly in organic forms, accounting for 81.57% of the total Se. The organic forms of selenium mainly present in Se proteins account for 73.53%, while 12.23% is in Se polysaccharides. Two Se-containing proteins (AB-SePA-22) and (AB-SePG-22) with Se contents of 4.935 µg/g and 6.083 µg/g were obtained. AB-SePA-22 appeared as four bands with molecular masses of 16.7, 21.7, 26.3, and 33.6 kDa, respectively. The Se content of the three Se-containing polysaccharides, namely AB-SeP-1, AB-SeP-2, and AB-SeP-3, were 1.911, 0.613, and 0.671 µg/g, respectively. AB-SeP-1 (3.1×103 Da) was composed of glucose and galactose in a 7.494:1 molar ratio, whereas AB-SeP-2 (2.1×104 Da and 3.5×104 Da) and AB-SeP-3 (1.1×105 Da) were composed of glucose, galactose, and mannose with molar ratios of 27.01:1.55:1 and 9.805:1:1.22, respectively. Moreover, crude Se polysaccharide and total soluble Se protein had good antioxidant activities on scavenging DPPH and hydroxyl radical, and further research is needed. PMID:25271981

  5. Vanadate and selenium inhibit the triiodothyronine induced enzyme activity and mRNA level for both fatty acid synthase and malic enzyme

    SciTech Connect

    Zhu, Y.; Mirmiran, R.; Goodridge, A.G.; Stapleton, S.R. Western Michigan Univ., Kalamazoo )

    1991-03-15

    In chick-embryo hepatocytes in culture, triiodothyronine stimulates enzyme activity, mRNA level and transcription rate for both fatty acid synthase (FAS) and malic enzyme (ME). Insulin alone has no effect but amplifies the induction by T3. Recent evidence has demonstrated the insulin-mimicking action of vanadate and selenium on various physiological processes. Little information, however, is available on the affects of vanadate and selenium on the expression of genes that are regulated by insulin. These studies were initiated to test the potential of vanadate and selenium to mimic the amplification affect of insulin on the T3 induction of FAS and ME. In chick-embryo hepatocytes incubated in a chemically defined medium, addition of T3 for 48h causes an increase in the enzyme activity and mRNA level for both FAS and ME. Addition of sodium vanadate or sodium selenate (20 {mu}M) coincident with the T3 almost completely inhibited the stimulation of FAS and ME activity and accumulation of their respective mRNA's. Fifty percent maximal inhibition occurred at about 3-40{mu}M vanadate or 5-10{mu}M selenium. Vanadate and selenium similarity inhibited FAS and ME enzyme activity and mRNA level when the cells were incubated in the presence of insulin and T3. The effect of these metals was selective; isocitrate dehydrogenase activity as well as the level of glyceraldehyde 3-phosphate mRNA were not affected by any of the additions made to the cells in culture. This effect by vanadate and selenium also does not appear to be a generalized effect of metals on lipogenic enzymes as molydate under similar experimental conditions has no effect on either the enzyme activity or mRNA level of FAS or ME. Studies are continuing to determine the mechanism of action of these agents on the regulation of lipogenic enzymes.

  6. Biomarkers of selenium status

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The essential trace element selenium (Se) has multiple biological activities, which depend on the level of Se intake. Relatively low Se intakes determine the expression of selenoenzymes in which it serves as an essential constituent. Higher intakes have been shown to have anti-tumorigenic potentia...

  7. Synchrotron X-ray imaging reveals a correlation of tumor copper speciation with Clioquinol's anticancer activity

    SciTech Connect

    Barrea, Raul A.; Chen, Di; Irving, Thomas C.; Dou, Q. Ping

    2009-10-21

    Tumor development and metastasis depend on angiogenesis that requires certain growth factors, proteases, and the trace element copper (Cu). Recent studies suggest that Cu could be used as a novel target for cancer therapies. Clioquinol (CQ), an antibiotic that is able to form stable complexes with Cu or zinc (Zn), has shown proteasome-inhibitory, androgen receptor-suppressing, apoptosis-inducing, and antitumor activities in human cancer cells and xenografts. The mechanisms underlying the interaction of CQ with cellular Cu, the alteration of the Cu/Zn ratio and the antitumor role of CQ in vivo have not been fully elucidated. We report here that Cu accumulates in tumor tissue and that the Cu/Zn balances in tumor, but not normal, tissue change significantly after the treatment with CQ. Cu speciation analysis showed that the Cu(I) species is predominant in both normal and tumor tissues and that Cu(II) content was significantly increased in tumor, but not normal tissue after CQ treatment. Our findings indicate that CQ can interact with cellular Cu in vivo, dysregulates the Cu/Zn balance and is able to convert Cu(I) to Cu(II) in tumor tissue. This conversion of Cu(I) to Cu(II) may be associated with CQ-induced proteasome inhibition and growth suppression in the human prostate tumor xenografts.

  8. Selenium sulfide

    Integrated Risk Information System (IRIS)

    Selenium sulfide ; CASRN 7446 - 34 - 6 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogenic

  9. Comparison of Mercury Measurement Methods Using Two Active Filter Measurement Methods and a Tekran Speciation Unit

    NASA Astrophysics Data System (ADS)

    Pierce, A.; Gustin, M. S.; Huang, J.; Heidecorn, K.

    2014-12-01

    Three active mercury (Hg) measurement methods were operated side by side at an urban site (University of Nevada, Reno College of Agriculture Greenhouse facility, elev. 1370 m) in Reno, and at a high elevation site (Peavine Peak, elev. 2515 m) adjacent to Reno from December 2013 to October 2014. A model 602 BetaPlus Teledyne Advanced Pollution Instrumentation (TAPI, San Diego, CA USA) particulate measurement system was used to collect particulate matter on a 47 mm diameter cation exchange membrane (CEM, PN# MSTGS3R Mustang S, Pall Corp. Port Washington, NY) at a rate of 16.7 lpm for 24 hours to four days. Particulate concentrations were calculated using beta attenuation across the filters (non-destructive to filter material); the CEM filters were then analyzed for total Hg on a Tekran Total Hg Analysis system (model 2600, Tekran Instruments Corp. Knoxville, TN, USA). Concurrently, samples were collected on an active Hg membrane system. The active Hg membrane system consisted of 3 CEM filters sampling at a rate of 1 lpm for one to two weeks. CEM filters were then analyzed on the Tekran 2600. A Tekran speciation unit (model 1130, 1135, 2537) was also in operation and ambient air samples were analyzed for gaseous elemental Hg (GEM), gaseous oxidized Hg (GOM), and particulate bound Hg (PBM). Both the 602 BetaPlus system and the active Hg membrane system should collect RM on the CEM filters. The active Hg membrane system most likely captures mainly GOM based on previous tests with the Teflon inlet setup that indicated there was high static electricity effective in removing particulate matter. Flow rate and length of measurement (24 hours vs. four days) affected the Hg concentrations on the 602 BetaPlus system. Based on these measurements we hypothesize that, due to the high flow rate, and therefore short retention time, the 602 BetaPlus only captured PBM. It is also possible that there was loss of Hg to inlet walls due to the longer inlet on the 602 BetaPlus system

  10. Tolerance of the preruminant calf for selenium in milk replacer

    SciTech Connect

    Jenkins, K.J.; Hidiroglou, M.

    1986-07-01

    Calves were fed skim milk powder-based milk replacer containing either .2, 1, 3, 5, or 10 ppm selenium (added as sodium selenate) in the dry matter from 3 to 45 d of age to estimate the lowest amount of dietary selenium that would reduce calf performance and feed utilization. Only at the highest selenium (10 ppm) did calves show reduced average daily gain and feed efficiency and lower blood packed cell volume. Apparent digestibility of dry matter, nitrogen, and lipid, and plasma creatine phosphokinase activity were not affected by any of the selenium intakes. In general, selenium in blood, bile, duodenal mucosa, liver, kidney, and muscle reflected selenium intakes with liver and kidney reaching the highest selenium concentrations. Postmortem examinations of calves revealed no gross abnormalities for any of the selenium treatments. The preruminant calf is very tolerant of high inorganic selenium concentrations in skim milk powder-based milk replacer.

  11. Field-Measured Oxidation Rates of Biologically Reduced Selenium in Sludge

    SciTech Connect

    Benson, Sally M.; Daggett, John; Zawislansi, Peter

    1999-05-01

    Sludge generated during surface-water transport or biological treatment of selenium laden agricultural drainage water contains high concentrations (20-100 mg/kg) of selenium. Finding safe and economical sludge disposal methods requires understanding of the biogeochemical processes that change selenium speciation (after placed at a disposal site). Two experiments, each comparing 3 treatments for sludge disposal has resulted in data on changes in selenium speciation spanning an eight year period. Treatments included direct application to upland soils and application with tillage to depths of 15 cm and 30 cm. Soil cores, soil water samples and groundwater monitoring were used to track changes in selenium speciation and transport of re-oxidized forms of selenium. Measurements demonstrate the slow re-oxidation of reduced forms of selenium, largely elemental and organically associated forms, to selenate and selenite. Downward transport of these re-oxidized forms of selenium are driven by winter rains. Field measured re-oxidation rates for these field trials are presented and compared to selenium re-oxidation rates in formerly ponded areas at Kesterson Reservoir, California.

  12. Selenium deficiency mitigates hypothyroxinemia in iodine-deficient subjects.

    PubMed

    Vanderpas, J B; Contempré, B; Duale, N L; Deckx, H; Bebe, N; Longombé, A O; Thilly, C H; Diplock, A T; Dumont, J E

    1993-02-01

    Studies were performed to assess the role of combined selenium and iodine deficiency in the etiology of endemic myxedematous cretinism in a population in Zaire. One effect of selenium deficiency may be to lower glutathione peroxidase activity in the thyroid gland, thus allowing hydrogen peroxide produced during thyroid hormone synthesis to be cytotoxic. In selenium-and-iodine-deficient humans, selenium supplementation may aggravate hypothyroidism by stimulating thyroxin metabolism by the selenoenzyme type I iodothyronine 5'-deiodinase. Selenium supplementation is thus not indicated without iodine or thyroid hormone supplementation in cases of combined selenium and iodine deficiencies. PMID:8427203

  13. The leaching characteristics of selenium from coal fly ashes

    SciTech Connect

    Wang, T.; Wang, J.; Burken, J.G.; Ban, H.; Ladwig, K.

    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 for 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.

  14. Influence of selenium supplementation on fatty acids profile and biological activity of four edible amaranth sprouts as new kind of functional food.

    PubMed

    Pasko, Pawel; Gdula-Argasinska, Joanna; Podporska-Carroll, Joanna; Quilty, Brid; Wietecha-Posluszny, Renata; Tyszka-Czochara, Malgorzata; Zagrodzki, Pawel

    2015-08-01

    Suitability assessment of amaranth sprouts as a new functional food was carried out. The optimisation of sprouting process and the influence of selenium supplementation, in doses 10, 15, and 30 mg/l of selenium as sodium selenite, on amaranth growth and fatty acid profile were examined. Methods such as FRAP, DPPH, polyphenols content and GPX activity were applied to characterize antioxidant potential of seeds and sprouts of four different edible amaranth genera. E. coli, S. aureus, C. albicans were used to evaluate amaranth sprouts antimicrobial properties. Interaction between amaranth sprouts and biological systems was assessed by analysing antibacterial and antifungal properties with a disc diffusion test. The studies proved amaranth sprouts to be potentially attractive as functional food. As confirmed by all the data amaranth sprouts are suitable as a moderate selenium accumulator and are rich in essential fatty acids, especially linoleic and alpha-linolenic acids, which are precursors of long chain polyunsaturated fatty acids. Thus, it opens dietary opportunities for amaranth sprouts. They can also serve as a moderate source of antioxidant compounds. Nevertheless, the experiments revealed neither antibacterial, nor antifungal properties of sprouts. In general, amaranth sprouts biological activity under evaluation has failed to prove to be significantly impacted by selenium fertilization. PMID:26243894

  15. The level of selenium and some other trace elements in different Libyan arable soils using instrumental neutron activation analysis.

    PubMed

    El-Ghawi, U M; Al-Fakhri, S M; Al-Sadeq, A A; Bejey, M M; Doubali, K K

    2007-10-01

    Elemental analysis of soils from two different arable regions in Libya was carried out to measure the level of many trace elements. Instrumental neutron activation analysis was used for the determination of 10 elements, viz., (Ba, Ce, Co, Cr, Cs, Fe, Sc, Se, Th, and Zn), using their long-lived radionuclides. The accuracy of the measurements has been evaluated by analyzing two IAEA soil reference materials: IAEA Soil-7 and IAEA leak sediment SL-1; precision has been estimated by triplicate analysis of the sample and that of the reference material. Irradiations were carried out at the Tajura Research Center reactor, at 5-MW power level. It is clear that in the Libyan soil selenium concentration is somewhat lower than in other countries. The results show that trace metal concentrations in Libyan clay surface soil are higher than the sandy soil. PMID:17914223

  16. 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

  17. Effect of Selenium Supplementation on Glutathione Peroxidase Enzyme Activity in Patients With Chronic Kidney Disease: A Randomized Clinical Trial

    PubMed Central

    Sedighi, Omid; Zargari, Mehryar; Varshi, Gharmohammad

    2014-01-01

    Background: Plasma selenium (Se) concentration and glutathione peroxidase (GSH-Pxs) enzyme activity of the patients with chronic kidney disease (CKD) are usually lower than healthy individuals; however, the effect of Se supplementation on the GSH-Pxs activity in those patients remains unclear. Objectives: This study aimed to assess the effect of Se supplementation on plasma Se concentration and red blood cell (RBC) GSH-Pxs activity in patients with different stages of CKD. Patients and Methods: In this randomized clinical trial, forty-five patients with CKD who attended in a nephrology clinic were recruited. The patients were randomly allocated into three groups according to their creatinine clearance rate and were supplemented with daily Se 200 mcg for three months. Plasma Se concentration and RBC GSH-Pxs activity were measured in each patient at the beginning and at the end of the study. This clinical trial was registered in the Iranian Registry of Clinical Trials (www.irct.ir) with registration number ID of IRCT201305318501N2. Results: Plasma Se concentration and RBC GSH-Pxs activity increased significantly in all three groups of patients with CKD (P < 0.05). There were no significant differences between three groups regarding baseline plasma Se (P = 0.268) and RBC GSH-Pxs activity (P = 0.741). Conclusions: Se supplementation can increase plasma Se concentration and RBC GSH-Pxs activity in patients with different stages of CKD. PMID:25032143

  18. Selenium transformation in coal mine spoils: Its environmental impact assessment

    SciTech Connect

    Harness, J.; Atalay, A.; Koll, K.J.; Zhang, H.; Maggon, D.

    1991-12-31

    The objective of this program was to conduct an environmental impact assessment study for selenium from coal mine spoils. The use of in-situ lysimetry to predict selenium speciation, transformation, and mobility under natural conditions was evaluated. The scope of the study was to construct and test field-scale lysimeter and laboratory mini-column to assess mobility and speciation of selenium in coal mine overburden and soil systems; to conduct soil and groundwater sampling throughout the state of Oklahoma for an overall environmental impact assessment of selenium; and to conduct an in-depth literature review on the solubility, speciation, mobility, and toxicity of selenium from various sources. Groundwater and surface soil samples were also collected from each county in Oklahoma. Data collected from the lysimeter study indicated that selenium in the overburden of the abandoned mine site was mainly found in the selenite form. The amount of selenite found was too low and immobile to be of concern to the environment. The spoil had equilibrated long enough (over 50 years) that most of the soluble forms of selenium have already been lost. Examination of the overburden indicated the presence of pyrite crystals that precipitated over time. The laboratory mini-column study indicated that selenite is quite immobile and remained on the overburden material even after leaching with dilute acid. Data from groundwater samples indicated that based on the current permissible level for selenium in groundwater (0.01 mg Se/L), Oklahoma groundwater is widely contaminated with the element. However, according to the new regulation (0.05 mg Se/L), which is to be promulgated in 1992, only 9 of the 77 counties in the state exceed the limit.

  19. Part A. Neutron activation analysis of selenium and vanadium in biological matrices. Part B. Isomeric transition activation in aqueous solutions of alkyl bromides

    SciTech Connect

    Ebrahim, A.

    1988-01-01

    Several procedures were evaluated for determination of selenium in biological fluids and vanadium in biological tissues by neutron activation analysis (NAA) employing {sup 77m}Se and {sup 52}V isotopes, respectively. Procedures for determination of total selenium, trimethylselenonium (TMSe) ion and selenite (SeO{sub 3}{sup 2{minus}}) ion in urine and serum and for total selenoamino acids in urine were developed by utilizing anion exchange chromatography and molecular NAA. A pre-column derivatization of selenoamino acids with o-phthalaldehyde was necessary for their determination. Also an analytical approach was developed for determination of trace vanadium in liver samples from normal and diabetic rats as well as human and cow. Reactions of bromine-80 activated by radiative neutron capture and bromine-82 activated by isomeric transition were investigated in aqueous solutions of bromomethane and 1-bromobutane. Bromine-80 organic yields decreased with decreasing solute concentrations. The tendency for aggregation of the solute molecules diminished as the solute concentration approached zero where the probable state of the solute approached a monomolecular dispersion. Unlike reactions of {sup 80}Br born by {sup 79}Br(n,{gamma}){sup 80}Br reaction, the total organic product yields resulting from the {sup 82m}Br(I.T.){sup 82}Br process showed no solute concentration dependence.

  20. Supplementation with Sodium Selenite and Selenium-Enriched Microalgae Biomass Show Varying Effects on Blood Enzymes Activities, Antioxidant Response, and Accumulation in Common Barbel (Barbus barbus)

    PubMed Central

    Kouba, Antonín; Velíšek, Josef; Stará, Alžběta; Masojídek, Jiří; Kozák, Pavel

    2014-01-01

    Yearling common barbel (Barbus barbus L.) were fed four purified casein-based diets for 6 weeks in outdoor cages. Besides control diet, these were supplemented with 0.3 mg kg−1 dw selenium (Se) from sodium selenite, or 0.3 and 1.0 mg kg−1 from Se-enriched microalgae biomass (Chlorella), a previously untested Se source for fish. Fish mortality, growth, Se accumulation in muscle and liver, and activity of selected enzymes in blood plasma, muscle, liver, and intestine were evaluated. There was no mortality, and no differences in fish growth, among groups. Se concentrations in muscle and liver, activity of alanine aminotransferase and creatine kinase in blood plasma, glutathione reductase (GR) in muscle, and GR and catalase in muscle and liver suggested that selenium from Se-enriched Chlorella is more readily accumulated and biologically active while being less toxic than sodium selenite. PMID:24772422

  1. Supplementation with sodium selenite and selenium-enriched microalgae biomass show varying effects on blood enzymes activities, antioxidant response, and accumulation in common barbel (Barbus barbus).

    PubMed

    Kouba, Antonín; Velíšek, Josef; Stará, Alžběta; Masojídek, Jiří; Kozák, Pavel

    2014-01-01

    Yearling common barbel (Barbus barbus L.) were fed four purified casein-based diets for 6 weeks in outdoor cages. Besides control diet, these were supplemented with 0.3 mg kg(-1) dw selenium (Se) from sodium selenite, or 0.3 and 1.0 mg kg(-1) from Se-enriched microalgae biomass (Chlorella), a previously untested Se source for fish. Fish mortality, growth, Se accumulation in muscle and liver, and activity of selected enzymes in blood plasma, muscle, liver, and intestine were evaluated. There was no mortality, and no differences in fish growth, among groups. Se concentrations in muscle and liver, activity of alanine aminotransferase and creatine kinase in blood plasma, glutathione reductase (GR) in muscle, and GR and catalase in muscle and liver suggested that selenium from Se-enriched Chlorella is more readily accumulated and biologically active while being less toxic than sodium selenite. PMID:24772422

  2. Effect of dietary organic selenium on muscle proteolytic activity and water-holding capacity in pork.

    PubMed

    Calvo, L; Toldrá, F; Aristoy, M C; López-Bote, C J; Rey, A I

    2016-11-01

    This study evaluates the effect of dietary selenium (Se) supplementation source (organic, Se-enriched yeast; SY vs. inorganic, sodium selenite; SS), dose (0.2: L vs. 0.4: H mg/kg) and the combination of Se and vitamin E (VITE+SS) for 26days on drip loss, TBARS, colour changes, myofibrillar protein pattern and proteolysis in pork. The lowest water losses were observed in the SY-H group when compared to the others. SY-H and VITE+SS groups presented lower myofibrillar protein hydrolysis/oxidation. VITE+SS supplementation also resulted in higher PRO, TRP and PHE content at days 2 and 7, whereas the SY group showed increased GLY and CAR and tended to have higher TAU and ANS at day 2. The myofibrillar fragmentation index was not modified by the dietary treatment; however, at day 8, it tended to be higher in groups supplemented with SeY and VITE+SS. The results of the present study might indicate a possible relation between muscle proteolysis and water loss. PMID:27232379

  3. The protection of selenium on cadmium-induced inhibition of spermatogenesis via activating testosterone synthesis in mice.

    PubMed

    Ren, Xiang-mei; Wang, Gai-gai; Xu, Dong-qing; Luo, Kang; Liu, Yu-xin; Zhong, Yi-hong; Cai, Yun-qing

    2012-10-01

    Selenium (Se) is an essential trance element in testis. However, the potential protective effects of Se against cadmium (Cd)-induced reproductive toxicity remained to be elucidated. Male ICR mice were orally administered by gavage with Na2SeO3 (0.1, 0.2, 0.4 mg/kg BW) for 1h prior to CdCl2 (5 mg/kg BW) alone or in combination for 15, 25 or 35 days. Cd exposure caused a significant decrease in body weight, sperm concentration and motility as well as plasma testosterone level which was accompanied by decreased antioxidant enzymatic activity of SOD and GSH-Px and by increased lipid peroxidation (as malondialdehyde, MDA). Se pretreatment compensated deficits in the sperm parameters (concentration, motility and morphology) induced by Cd. Se (0.4 mg/kg BW) treatment significantly increased serum testosterone level that was reduced by Cd (on 15th, 25th and 35th day) (P<0.01). Se treatment ameliorated Cd-induced reduction in testicular steroidogenic acute regulatory (StAR) and 17β-hydroxysteroid dehydrogenase (17β-HSD) activities. The present study suggest that the protective potential of Se against Cd-induced reprotoxicity might be due to up-regulation StAR and testosterone synthetic enzyme activity, which could be useful for increasing testosterone synthesis for achieving optimum protection in sperm quality and spermatogenesis. PMID:22828241

  4. Digital radiology using active matrix readout of amorphous selenium: radiation hardness of cadmium selenide thin film transistors.

    PubMed

    Zhao, W; Waechter, D; Rowlands, J A

    1998-04-01

    A flat-panel x-ray imaging detector using active matrix readout of amorphous selenium (a-Se) is being investigated for digital radiography and fluoroscopy. The active matrix consists of a two-dimensional array of thin film transistors (TFTs). Radiation penetrating through the a-Se layer will interact with the TFTs and it is important to ensure that radiation induced changes will not affect the operation of the x-ray imaging detector. The methodology of the present work is to investigate the effects of radiation on the characteristic curves of the TFTs using individual TFT samples made with cadmium selenide (CdSe) semiconductor. Four characteristic parameters, i.e., threshold voltage, subthreshold swing, field effect mobility, and leakage current, were examined. This choice of parameters was based on the well established radiation damage mechanisms for crystalline silicon metal-oxide-semiconductor field-effect transistors (MOSFETs), which have a similar principle of operation as CdSe TFTs. It was found that radiation had no measurable effect on the leakage current and the field effect mobility. However, radiation shifted the threshold voltage and increased the subthreshold swing. But even the estimated lifetime dose (50 Gy) of a diagnostic radiation detector will not affect the normal operation of an active matrix x-ray detector made with CdSe TFTs. The mechanisms of the effects of radiation will be discussed and compared with those for MOSFETs and hydrogenated amorphous silicon (a-Si:H) TFTs. PMID:9571621

  5. Solid/solution Cu fractionations/speciation of a Cu contaminated soil after pilot-scale electrokinetic remediation and their relationships with soil microbial and enzyme activities.

    PubMed

    Wang, Quan-Ying; Zhou, Dong-Mei; Cang, Long; Li, Lian-Zhen; Wang, Peng

    2009-01-01

    The aim of this study was to investigate the detailed metal speciation/fractionations of a Cu contaminated soil before and after electrokinetic remediation as well as their relationships with the soil microbial and enzyme activities. Significant changes in the exchangeable and adsorbed-Cu fractionations occurred after electrokinetic treatment, while labile soil Cu in the solution had a tendency to decrease from the anode to the cathode, and the soil free Cu(2+) ions were mainly accumulated in the sections close to the cathode. The results of regression analyses revealed that both the soil Cu speciation in solution phase and the Cu fractionations in solid phase could play important roles in the changes of the soil microbial and enzyme activities. Our findings suggest that the bioavailability of soil heavy metals and their ecotoxicological effects on the soil biota before and after electroremediation can be better understood in terms of their chemical speciation and fractionations. PMID:19427727

  6. The genotoxicity of selenium.

    PubMed

    Shamberger, R J

    1985-07-01

    Selenium at nutritional levels has been shown to have numerous anticarcinogenic or preventative effects against carcinogen-induced breast, colon, liver and skin cancer in animals. Many of these anticarcinogenic effects have been summarized. In addition, numerous mutagenic and antimutagenic effects of selenium compounds have been reported. Some of the selenium compounds frequently tested for mutagenicity are listed in Table 1. Because of the numerous reported anticarcinogenic and preventative effects of selenium, many individuals are supplementing their diets with amounts of selenium that are greater than the recommended daily requirement. Selenium is also used widely in industrial products such as selenium rectifiers, photoelectric batteries, alloys and paints. Because selenium at higher levels is known to be toxic, there should be a greater understanding about its genotoxic as well as its beneficial effect. The object of this review is to summarize experimental evidence both for the antimutagenic and the mutagenic effect of selenium. PMID:3923345

  7. Biomedical potential of actinobacterially synthesized selenium nanoparticles with special reference to anti-biofilm, anti-oxidant, wound healing, cytotoxic and anti-viral activities.

    PubMed

    Ramya, Suseenthar; Shanmugasundaram, Thangavel; Balagurunathan, Ramasamy

    2015-10-01

    Currently, there is an ever-increasing need to develop environmentally benign processes in place of synthetic protocols. As a result, researchers in the field of nanoparticle synthesis are focusing their attention on microbes from rare biological ecosystems. One potential actinobacterium, Streptomyces minutiscleroticus M10A62 isolated from a magnesite mine had the ability to synthesize selenium nanoparticles (SeNPs), extracellularly. Actinobacteria mediated SeNP synthesis were characterized by UV-visible, Fourier transform infrared (FT-IR), X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX) and high resolution transmission electron microscopy (HR-TEM) analysis. The UV-spectral analysis of SeNPs indicated the maximum absorption at 510nm, FT-IR spectral analysis confirms the presence of capping protein, peptide, amine and amide groups. The selenium signals confirm the presence of SeNPs. All the diffraction peaks in the XRD pattern and HR-TEM confirm the size of SeNPs in the range of 10-250nm. Further, the anti-biofilm and antioxidant activity of the SeNPs increased proportionally with rise in concentration, and the test strains reduced to 75% at concentration of 3.2μg. Selenium showed significant anti-proliferative activity against HeLa and HepG2 cell lines. The wound healing activity of SeNPs reveals that 5% selenium oinment heals the excision wound of Wistar rats up to 85% within 18 days compared to the standard ointment. The biosynthesized SeNPs exhibited good antiviral activity against Dengue virus. The present study concludes that extremophilic actinobacterial strain was a novel source for SeNPs with versatile biomedical applications and larger studies are needed to quantify these observed effects of SeNPs. PMID:26302909

  8. Preconcentration and Speciation of Trace Elements and Trace-Element Analogues of Radionuclides by Neutron Activation Analysis

    SciTech Connect

    Chatt, A.

    1999-11-14

    We have developed a number of preconcentration neutron activation analysis (PNAA) methods in our laboratory for the determination of trace elements in a variety of complex sample matrices. We developed a number of cocrystallization and coprecipitation methods for the determination of trace elements in water samples. We developed several methods for the determination of I in foods and diets. We have developed a number of PNAA methods in our laboratory We determined As and Sb in geological materials and natural waters by coprecipitation with Se and Au in silicate rocks and ores by coprecipitation with Te followed by NAA. We developed an indirect NAA method for the determination of B in leachates of borosilicate glass. We have been interested in studying the speciation of Am, Tc, and Np in simulated vitrified groundwater leachates of high-level wastes under oxid and anoxic conditions using a number of techniques. We then used PNAA methods to study speciation of trace-element analogues of radionuclides. We have been able to apply biochemical techniques and NAA for the separation, preconcentration, and characterization of metalloprotein and protein-bound trace-element species in subcellular fractions of bovine kidneys. Lately, we have concentrated our efforts to develop chemical and biochemical methods in conjunction with NAA, NMR, and MS for the separation and identification of extractable organohalogens (EOX) in tissues of beluga whales, cod, and northern pink shrimp

  9. Special Speciation

    ERIC Educational Resources Information Center

    Countryman, Lyn L.; Maroo, Jill D.

    2015-01-01

    Considerable anecdotal evidence indicates that some of the most difficult concepts that both high school and undergraduate elementary-education students struggle with are those surrounding evolutionary principles, especially speciation. It's no wonder that entry-level biology students are confused, when biologists have multiple definitions of…

  10. 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. PMID:26045617

  11. Selenium speciation in radix puerariae using ultrasonic assisted extraction combined with reversed phase high performance liquid chromatography-inductively coupled plasma-mass spectrometry after magnetic solid-phase extraction with 5-sulfosalicylic acid functionalized magnetic nanoparticles

    NASA Astrophysics Data System (ADS)

    Cao, Yupin; Yan, Lizhen; Huang, Hongli; Deng, Biyang

    2016-08-01

    A new method for determination of selenium species in radix puerariae was described. The method consists of sample enrichment with 5-sulfosalicylic acid (SSA)-functionalized silica-coated magnetic nanoparticles (SMNPs), high performance liquid chromatography (HPLC) separation, and online detection using inductively coupled plasma mass spectrometry (ICP-MS). The selenium species were extracted using ultrasonic extraction system with a mixture of protease K and lipase. The SSA-SMNPs were used to enrich trace amounts of selenite [Se(IV)], selenate [Se(VI)], selenomethionine (SeMet), and selenocystine (SeCys2) from lower selenium containing samples. Under the optimal conditions, the limits of detection (3σ) for SeCys2, Se(IV), SeMet and Se(VI) were observed as 0.0023, 0.0015, 0.0043, and 0.0016 ng mL- 1, respectively. The RSD values (n = 6) of method for intraday were observed between 0.5% and 0.9%. The RSD values of method for interday were less than 1.3%. The linear concentration ranges for SeCys2, Se(IV), SeMet and Se(VI) were 0.008-1000, 0.005-200, 0.015-500 and 0.006-200 ng mL- 1, respectively. The detection limits of this method were improved by 10 times due to the enrichment with the SSA-SMNP extraction. The contents of SeCys2, Se(IV), SeMet, and Se(VI) in radix puerariae were determined as 0.0140, 0.171, 0.0178, and 0.0344 μg g- 1, respectively. The recoveries were in the range of 95.6%-99.4% and the RSDs (n = 6) of recoveries were less than 1.5%.

  12. Speciation change and redistribution of arsenic in soil under anaerobic microbial activities.

    PubMed

    Xu, Liying; Wu, Xi; Wang, Shaofeng; Yuan, Zidan; Xiao, Fan; Yang, Ming; Jia, Yongfeng

    2016-01-15

    Arsenic speciation and behavior in soil are strongly affected by redox conditions. This work investigated speciation transformation and redistribution of arsenic in soil under anaerobic conditions. The effect of microbial sulfidogenesis on these processes was examined by addition of sulfate to the incubation systems. As(III) was found to be the dominant arsenic species in solution during the process of anaerobic incubation. The change of dissolved As concentration with incubation time showed "M" shaped profiles, e.g. the curves displaying two peaks at approximately 24 h and 240 h for the system with added sulfate. Arsenic was released and reduced to As(III) in the early stage of the incubation, and then resequestered into the solid phase. After excess sulfide was generated, the resequestered arsenic was released again (probably due to the dissolution of arsenic sulfide by dissolved sulfide ions) via the formation of thioarsenite. At the end of the incubation process, most of the dissolved arsenic was removed again from solution. The findings may have important implications to the fate of arsenic in flooded sulfur-rich soils. PMID:26434533

  13. Selenium content in wheat and estimation of the selenium daily intake in different regions of Algeria.

    PubMed

    Beladel, B; Nedjimi, B; Mansouri, A; Tahtat, D; Belamri, M; Tchanchane, A; Khelfaoui, F; Benamar, M E A

    2013-01-01

    In this work, we have measured the selenium content in wheat produced locally in eight different regions of Algeria from east to west, and we have established the annual consumption of selenium for five socio-professional categories. Instrumental neutron activation analysis is used. The selenium levels in wheat samples varied from 21 (Tiaret) to 153 μg/kg (Khroub), with a mean value about 52 μg/kg. The mean of selenium daily consumption from ingestion of wheat per person in the eight regions varied from 32 to 52 μg/day which is close to the minimal FAO recommendation. PMID:23079485

  14. Micro-spectroscopic investigation of selenium-bearing minerals from the Western US Phosphate Resource Area

    PubMed Central

    Ryser, Amy L; Strawn, Daniel G; Marcus, Matthew A; Johnson-Maynard, Jodi L; Gunter, Mickey E; Möller, Gregory

    2005-01-01

    Mining activities in the US Western Phosphate Resource Area (WPRA) have released Se into the environment. Selenium has several different oxidation states and species, each having varying degrees of solubility, reactivity, and bioavailability. In this study we are investigating the speciation of Se in mine-waste rocks. Selenium speciation was determined using bulk and micro-x-ray absorption spectroscopy (XAS), as well as micro-x-ray fluorescence mapping. Rocks used for bulk-XAS were ground into fine powders. Shale used for micro-XAS was broken along depositional planes to expose unweathered surfaces. The near edge region of the XAS spectra (XANES) for the bulk rock samples revealed multiple oxidation states, with peaks indicative of Se(-II), Se(IV), and Se(+VI) species. Micro-XANES analysis of the shale indicated that three unique Se-bearing species were present. Using the XANES data together with ab initio fitting of the extended x-ray absorption fine structure region of the micro-XAS data (micro-EXAFS) the three Se-bearing species were identified as dzharkenite, a di-selenide carbon compound, and Se-substituted pyrite. Results from this research will allow for a better understanding of the biogeochemical cycling of Se in the WPRA.

  15. 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.

  16. Selenium: Element of Contrasts

    ERIC Educational Resources Information Center

    Goldsmith, Robert H.; And Others

    1978-01-01

    Reports on recent findings concerning the impact of selenium on human and animal health. In its various oxidation states, different concentrations of selenium may be helpful or detrimental to human health. (CP)

  17. Selenium: Poison and Preventive.

    ERIC Educational Resources Information Center

    Marmion Howe, Sister

    1978-01-01

    Selenium is an essential nutrient to the human body, but it can reach toxic levels causing a disease called selenosis. This article discusses selenium, its geographical distribution, toxicity, nutritional role, and carcinogenicity. (MA)

  18. Novel walnut peptide–selenium hybrids with enhanced anticancer synergism: facile synthesis and mechanistic investigation of anticancer activity

    PubMed Central

    Liao, Wenzhen; Zhang, Rong; Dong, Chenbo; Yu, Zhiqiang; Ren, Jiaoyan

    2016-01-01

    This contribution reports a facile synthesis of degreased walnut peptides (WP1)-functionalized selenium nanoparticles (SeNPs) hybrids with enhanced anticancer activity and a detailed mechanistic evaluation of its superior anticancer activity. Structural and chemical characterizations proved that SeNPs are effectively capped with WP1 via physical absorption, resulting in a stable hybrid structure with an average diameter of 89.22 nm. A panel of selected human cancer cell lines demonstrated high susceptibility toward WP1-SeNPs and displayed significantly reduced proliferative behavior. The as-synthesized WP1-SeNPs exhibited excellent selectivity between cancer cells and normal cells. The targeted induction of apoptosis in human breast adenocarcinoma cells (MCF-7) was confirmed by the accumulation of arrested S-phase cells, nuclear condensation, and DNA breakage. Careful investigations revealed that an extrinsic apoptotic pathway can be attributed to the cell apoptosis and the same was confirmed by activation of the Fas-associated with death domain protein and caspases 3, 8, and 9. In addition, it was also understood that intrinsic apoptotic pathways including reactive oxygen species generation, as well as the reduction in mitochondrial membrane potential, are also involved in the WP1-SeNP-induced apoptosis. This suggested the involvement of multiple apoptosis pathways in the anticancer activity. Our results indicated that WP1-SeNP hybrids with Se core encapsulated in a WP1 shell could be a highly effective method to achieve anticancer synergism. Moreover, the great potential exhibited by WP1-SeNPs could make them an ideal candidate as a chemotherapeutic agent for human cancers, especially for breast cancer. PMID:27143875

  19. Novel walnut peptide-selenium hybrids with enhanced anticancer synergism: facile synthesis and mechanistic investigation of anticancer activity.

    PubMed

    Liao, Wenzhen; Zhang, Rong; Dong, Chenbo; Yu, Zhiqiang; Ren, Jiaoyan

    2016-01-01

    This contribution reports a facile synthesis of degreased walnut peptides (WP1)-functionalized selenium nanoparticles (SeNPs) hybrids with enhanced anticancer activity and a detailed mechanistic evaluation of its superior anticancer activity. Structural and chemical characterizations proved that SeNPs are effectively capped with WP1 via physical absorption, resulting in a stable hybrid structure with an average diameter of 89.22 nm. A panel of selected human cancer cell lines demonstrated high susceptibility toward WP1-SeNPs and displayed significantly reduced proliferative behavior. The as-synthesized WP1-SeNPs exhibited excellent selectivity between cancer cells and normal cells. The targeted induction of apoptosis in human breast adenocarcinoma cells (MCF-7) was confirmed by the accumulation of arrested S-phase cells, nuclear condensation, and DNA breakage. Careful investigations revealed that an extrinsic apoptotic pathway can be attributed to the cell apoptosis and the same was confirmed by activation of the Fas-associated with death domain protein and caspases 3, 8, and 9. In addition, it was also understood that intrinsic apoptotic pathways including reactive oxygen species generation, as well as the reduction in mitochondrial membrane potential, are also involved in the WP1-SeNP-induced apoptosis. This suggested the involvement of multiple apoptosis pathways in the anticancer activity. Our results indicated that WP1-SeNP hybrids with Se core encapsulated in a WP1 shell could be a highly effective method to achieve anticancer synergism. Moreover, the great potential exhibited by WP1-SeNPs could make them an ideal candidate as a chemotherapeutic agent for human cancers, especially for breast cancer. PMID:27143875

  20. Biosynthesis of selenium rich exopolysaccharide (Se-EPS) by Pseudomonas PT-8 and characterization of its antioxidant activities.

    PubMed

    Ye, Shuhong; Zhang, Jiajia; Liu, Zhaofang; Zhang, Yu; Li, Jiang; Li, Yao Olive

    2016-05-20

    Biosynthesis of organo-selenium is achieved by submerged fermentation of selenium-tolerant Pseudomonas PT-8. The end product of metabolic process is selenium-bearing exopolysaccharide (Se-EPS), which contains a higher content of uronic acid than the exopolysaccharide (EPS) by the strain without selenium in the culture medium. Selenium content in Se-EPS reached a maximum yield of 256.7 mg/kg when using an optimized culture condition. Crude Se-EPS was purified into two fractions-a pH neutral Se-EPS-1 and an acidic Se-EPS-2. Structure and chemical composition of Se-EPS-2 were investigated by chromatographic analyses. Results showed that Se-EPS-2 was a homogenous polysaccharide with molecular weight of 7.3 kDa, consisting of monosaccharides, rhamnose, arabinose, xylose, mannose, glucose and galactose with a molar ratio of 19.58:19.28:5.97:18.99:23.70:12.48, respectively. Compared to the EPS, the content of rhamnose in Se-EPS increased and molecular weight decreased. The Se-EPS had strong scavenging actions on DPPH•, •OH and •O2(-), which is much higher than the EPS. PMID:26917395

  1. Dietary selenium and prolonged exercise alter gene expression and activity of antioxidant enzymes in equine skeletal muscle.

    PubMed

    White, S H; Johnson, S E; Bobel, J M; Warren, L K

    2016-07-01

    Untrained Thoroughbred horses (6 mares and 6 geldings; 11 yr [SE 1] and 565 kg [SE 11]) were used to evaluate antioxidant gene expression and enzyme activity in blood and skeletal muscle in response to prolonged exercise after receiving 2 levels of dietary selenium for 36 d: 0.1 (CON; = 6) or 0.3 mg/kg DM (SEL; = 6). Horses were individually fed 1.6% BW coastal bermudagrass hay, 0.4% BW whole oats, and a mineral/vitamin premix containing no Se. Sodium selenite was added to achieve either 0.1 or 0.3 mg Se/kg DM in the total diet. On d 35, horses underwent 2 h of submaximal exercise in a free-stall exerciser. Blood samples were obtained before (d 0) and after 34 d of Se supplementation and on d 35 to 36 immediately after exercise and at 6 and 24 h after exercise. Biopsies of the middle gluteal muscle were obtained on d 0, before exercise on d 34, and at 6 and 24 h after exercise. Supplementation with Se above the NRC requirement (SEL) increased serum Se ( = 0.011) and muscle thioredoxin reductase (TrxR) activity ( = 0.051) but had no effect on glutathione peroxidase (GPx) activity in plasma, red blood cell (RBC) lysate, or muscle in horses at rest. Serum creatine kinase activity increased ( < 0.0001) in response to prolonged exercise but was not affected by dietary treatment. Serum lipid hydroperoxides were affected by treatment ( = 0.052) and were higher ( = 0.012) in horses receiving CON than SEL immediately following exercise. Muscle expression of was unchanged at 6 h but increased ( = 0.005) 2.8-fold 24 h after exercise, whereas muscle TrxR activity remained unchanged. Glutathione peroxidase activity increased in plasma (P < 0.0001) and decreased in RBC lysate ( = 0.010) after prolonged exercise. A Se treatment × time interaction was observed for RBC GPx activity (P = 0.048). Muscle and expression and GPx activity did not change during the 24-h period after exercise. Level of dietary Se had no overall effect on expression of , , , , , , or in muscle following

  2. Rational Incorporation of Selenium into Temozolomide Elicits Superior Antitumor Activity Associated with Both Apoptotic and Autophagic Cell Death

    PubMed Central

    Cheng, Yan; Sk, Ugir Hossain; Zhang, Yi; Ren, Xingcong; Zhang, Li; Huber-Keener, Kathryn J.; Sun, Yuan-Wan; Liao, Jason; Amin, Shantu; Sharma, Arun K.; Yang, Jin-Ming

    2012-01-01

    Background The DNA alkylating agent temozolomide (TMZ) is widely used in the treatment of human malignancies such as glioma and melanoma. On the basis of previous structure-activity studies, we recently synthesized a new TMZ selenium analog by rationally introducing an N-ethylselenocyanate extension to the amide functionality in TMZ structure. Principal Findings This TMZ-Se analog showed a superior cytotoxicity to TMZ in human glioma and melanoma cells and a more potent tumor-inhibiting activity than TMZ in mouse glioma and melanoma xenograft model. TMZ-Se was also effective against a TMZ-resistant glioma cell line. To explore the mechanism underlying the superior antitumor activity of TMZ-Se, we compared the effects of TMZ and TMZ-Se on apoptosis and autophagy. Apoptosis was significantly increased in tumor cells treated with TMZ-Se in comparison to those treated with TMZ. TMZ-Se also triggered greater autophagic response, as compared with TMZ, and suppressing autophagy partly rescued cell death induced by TMZ-Se, indicating that TMZ-Se-triggered autophagy contributed to cell death. Although mRNA level of the key autophagy gene, Beclin 1, was increased, Beclin 1 protein was down-regulated in the cells treated with TMZ-Se. The decrease in Beclin 1 following TMZ-Se treatment were rescued by the calpain inhibitors and the calpain-mediated degradation of Beclin1 had no effect on autophagy but promoted apoptosis in cells treated with TMZ-Se. Conclusions Our study indicates that incorporation of Se into TMZ can render greater potency to this chemotherapeutic drug. PMID:22496897

  3. Promising link between selenium and peroxisome proliferator activated receptor gamma in the treatment protocols of obesity as well as depression.

    PubMed

    Donma, M M; Donma, O

    2016-04-01

    Considerable interest has been given to the significance of peroxisome proliferator activated receptors (PPARs) in macronutrient metabolism, however, there is not sufficient data concerning the interactions between PPARs and micronutrients. Investigations performed on PPARγ and one of the essential micronutrients selenium (Se) have shown that both parameters may lead to alterations in obesity-related or mood disorders. Therefore, it is plausible to consider PPARγ and Se together as a powerful combination during the treatment of two associated diseases; obesity and depression. PPARγ has been shown to be involved in the antidepressant-like activity. It is also an important parameter to be considered in obesity as the master regulator of adipogenesis. The mechanism of action of PPARγ is initiated by ligand binding which induces a conformational change in the receptor. Se is capable of alleviating inflammatory signaling pathways. Obesity is associated with chronic low-grade inflammation. Depression is also defined as an inflammatory disorder. Inflammatory mediators such as tumor necrosis factor-alpha (TNFα) participate in the progression of depression. They are also obesity-associated parameters. Due to TNFα induced depressive-like behaviors and the positive association between this proinflammatory cytokine and obesity, TNFα-activated signaling pathways and those inhibiting them have recently gained importance as potential targets and therapeutic tools, respectively. More studies are necessary to develop compounds with therapeutic nature against depressive disorders and obesity. PPARγ is an important signaling pathway that occurs at the crossroads of depression and obesity. Se, aside from its anti-inflammatory, anticarcinogenic and antioxidative nature, affects also the way of PPARγ action. Se supplementation or fortification as well as the development of the partial agonists of PPARγ in which lipophilic Se compounds are used as ligand followed by

  4. Arsenic and Selenium

    NASA Astrophysics Data System (ADS)

    Plant, J. A.; Kinniburgh, D. G.; Smedley, P. L.; Fordyce, F. M.; Klinck, B. A.

    2003-12-01

    Arsenic (As) and selenium (Se) have become increasingly important in environmental geochemistry because of their significance to human health. Their concentrations vary markedly in the environment, partly in relation to geology and partly as a result of human activity. Some of the contamination evident today probably dates back to the first settled civilizations which used metals.Arsenic is in group 15 of the periodic table (Table 1) and is usually described as a metalloid. It has only one stable isotope, 75As. It can exist in the -III, -I, 0, III, and V oxidation states (Table 2).

  5. Decreased selenium levels in acute myocardial infarction

    SciTech Connect

    Kok, F.J.; Hofman, A.; Witteman, J.C.M.; de Bruijn, A.M.; Kruyssen, D.H.C.M.; de Bruin, M.; Valkenburg, H.A. )

    1989-02-24

    To study the association between selenium status and the risk of myocardial infarction, the authors compared plasma, erythrocyte, and toenail selenium levels and the activity of erythrocyte glutathione peroxidase among 84 patients with acute myocardial infarction and 84 population controls. Mean concentrations of all selenium measurements were lower in cases than controls. The differences were statistically significant, except for the plasma selenium level. A positive trend in the risk of acute myocardial infarction from high to low toenail selenium levels was observed, which persisted after adjustment for other risk factors for myocardial infarction. In contrast, erythrocyte glutathione peroxidase activity was significantly higher in cases than controls. Because toenail selenium level reflects blood levels up to one year before sampling, these findings suggest that a low selenium status was present before the infarction and, thus, may be of etiologic relevance. The higher glutathione peroxidase activity in the cases may be interpreted as a defense against increased oxidant stress either preceding or following the acute event.

  6. The effect of consumption of selenium enriched rye/wheat sourdough bread on the body's selenium status.

    PubMed

    Bryszewska, Malgorzata A; Ambroziak, Wojciech; Langford, Nicola J; Baxter, Malcolm J; Colyer, Alison; Lewis, D John

    2007-09-01

    The potential of selenium-enriched rye/wheat sourdough bread as a route for supplementing dietary selenium intakes is reported. In addition to their normal diets, 24 female volunteers (24 to 25 years old) were fed either selenium-enriched bread or non-enriched bread each day (68.02 and 0.84 microg selenium day(-1) respectively) for 4 weeks. The chemical form of the selenium in the bread had been characterised using HPLC-ICP-MS, which showed that 42% of the extractable selenium was present as selenomethionine. Plasma selenium levels and plasma platelet glutathione peroxidase (GPx1) activity were measured in the volunteers' blood over a 6-week period. A statistically significant difference (p = 0.001) was observed in the mean percentage change data, calculated from the plasma selenium level measurements for the enriched and control group, over the duration of the study. A comparable difference was not observed for the platelet GPx1 activity (p = 0.756), over the same period. Two weeks after cessation of the feeding stage, i.e., at t = 6 weeks, the mean percentage change value for the selenium plasma levels in the enriched group was still significantly elevated, suggesting that the absorbed selenium had been incorporated into the body's selenium reserves, and was then being slowly released back into the volunteers' blood. PMID:17721822

  7. The influence of atmospheric chromium on selenium content and glutathione peroxidase activity in blood of tannery workers.

    PubMed Central

    Gromadzińska, J; Wasowicz, W; Sklodowska, M; Bulikowski, W; Rydzyński, K

    1996-01-01

    The concentration of selenium and thiobarbituric acid reactive substances (TBARS) and activity of glutathione peroxidase (GSH-Px) were determined in blood of 34 workers of a tannery in Gniezno, Poland, who worked in an area containing chromium compounds. Fourteen workers were exposed to chromium compounds at concentrations of 0.11 +/- 0.07 mg Cr/m3 (mean +/- SD) and 20 at concentrations 5-10 times lower i.e., 0.022 +/- 0.009 mg Cr/m3. Excretion of Se in urine was measured in all of the investigated workers. Decreased Se concentration in whole blood and blood plasma and elevated TBARS concentration in blood plasma were found in the whole group of investigated tanners as compared to controls. Tanners working in areas with high chromium concentrations had a statistically significant decrease in Se concentration in blood and plasma and decreased urinary excretion of the microelement as compared with other tanners. TBARS concentration was 2.5 times lower in workers exposed to higher chromium concentrations (p < 0.005) than in other workers. Positive linear correlations were found between the concentration of Se in blood and the amount of the element excreted in urine (r = 0.48; p < 0.005), the concentration of Se in blood plasma and in urine (r = 0.46; p < 0.01), and the concentration of Se in blood and erythrocyte GSH-Px activity (r = 0.42; p < 0.02). The observed differences between Se concentration in blood and urine of tannery workers and people who are not employed in the industry may indicate a kind of specific adaptation of the body to the working environment containing chromium compounds. Images Figure 1. Figure 2. PMID:9118872

  8. Selenium in Cattle: A Review.

    PubMed

    Mehdi, Youcef; Dufrasne, Isabelle

    2016-01-01

    This review article examines the role of selenium (Se) and the effects of Se supplementation especially in the bovine species. Selenium is an important trace element in cattle. Some of its roles include the participation in the antioxidant defense the cattle farms. The nutritional requirements of Se in cattle are estimated at 100 μg/kg DM (dry matter) for beef cattle and at 300 μg/kg DM for dairy cows. The rations high in fermentable carbohydrates, nitrates, sulfates, calcium or hydrogen cyanide negatively influence the organism's use of the selenium contained in the diet. The Se supplementation may reduce the incidence of metritis and ovarian cysts during the postpartum period. The increase in fertility when adding Se is attributed to the reduction of the embryonic death during the first month of gestation. A use of organic Se in feed would provide a better transfer of Se in calves relative to mineral Se supplementation. The addition of Se yeasts in the foodstuffs of cows significantly increases the Se content and the percentage of polyunsaturated fatty acids (PUFA) in milk compared to the addition of sodium selenite. The enzyme 5-iodothyronine deiodinase is a seleno-dependent selenoprotein. It is one of the last proteins to be affected in the event of Se deficiency. This delay in response could explain the fact that several studies did not show the effect of Se supplementation on growth and weight gain of calves. Enrichment of Se in the diet did not significantly affect the slaughter weight and carcass yield of bulls. The impact and results of Se supplementation in cattle depend on physiological stage, Se status of animals, type and content of Se and types of Se administration. Further studies in Se supplementation should investigate the speciation of Se in food and yeasts, as well as understanding their metabolism and absorption. This constitute a path to exploit in order to explain certain different effects of Se. PMID:27120589

  9. Heavy metal speciation and acid treatment of activated sludge developed in a membrane bioreactor.

    PubMed

    Daskalakis, N; Katsou, E; Malamis, S; Haralambous, K J

    2013-01-01

    The aim of this study was to identify the heavy metals forms (exchangeable and bound to carbonate, Fe/Mn oxides, bound to organic matter and sulphide, and residual) associated with different fractions of excess sludge produced by a membrane bioreactor (MBR). Furthermore, the release of metals from the sludge to the liquid was investigated by applying acid treatment using 10% (v/v) H2SO4 (T = 25 degrees C, solid-liquid ratio 1:5 w/v) for contact time ranging from 15 min to 4 h. Metal partitioning in sludge, as determined by the sequential chemical extraction showed that the dominant form of both Ni and Zn was bound to the exchangeable and carbonate fraction; the latter were very unstable and sensitive to environmental conditions. The dominant Cu fraction was bound to organic matter and sulphide, while Pb was found to be mainly in the residual fraction which is very stable. Metal speciation after acidification with H2SO4 indicates changes of metal content in sludge and an increase of the exchangeable and bound to carbonate fraction for all metals except Cu. Acidification resulted in removal of 82% for Ni, 78% for Zn, 47% for Cu and 45% for Pb. PMID:24527621

  10. Vapor pressure, speciation, and chemical activities in highly concentrated sodium borate solutions at 277 and 317{degrees}C

    SciTech Connect

    Weres, O.

    1995-05-01

    The system H{sub 2}O - B{sub 2}O{sub 3} - Na{sub 2}O has been studied experimentally at 277 and 317{degrees}C. The activities of water and boric acid have been determined at mole ratios Na/B from 0 to 1.5, and total dissolved solids 3 to 8 weight percent. The activity of boric acid has been fitted to within experimental error using a speciation model with eight complex species. This model is consistent with the model previously published by Mesmer et al. The electrolyte properties of the liquid are modeled using the Pitzer-Simonson model of very concentrated electrolyte solutions. The calculated values of water activity agree with experiment, and the activity of NaOH and pOH have also been calculated. The potassium borate system also was briefly studied at 317{degrees}C, and is adequately described by a model with five complex species. The potassium borate liquid is more alkaline at K/B = 1 than a sodium borate liquid at the same mole ratio, but pOH in the two systems is the same at lower mole ratios.

  11. The effect of heteroatom substitution of sulfur for selenium in glucosidase inhibitors on intestinal α-glucosidase activities.

    PubMed

    Eskandari, Razieh; Jones, Kyra; Rose, David R; Pinto, B Mario

    2011-08-28

    The synthesis of selenium analogues of de-O-sulfonated ponkoranol, a naturally occurring sulfonium-ion glucosidase inhibitor isolated from Salacia reticulata, and their evaluation as glucosidase inhibitors against two recombinant intestinal enzymes maltase glucoamylase (MGAM) and sucrase isomaltase (SI) are described. PMID:21750824

  12. Chemical form of selenium affects its uptake, transport and glutathione peroxidase activity in the human intestinal Caco-2 cell model

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Determining the effect of selenium (Se) chemical form on uptake and transport in human intestinal cells is critical to assess Se bioavailability. In the present study, we measured the uptake and transport of various Se compounds in the human intestinal Caco-2 cell model. We found that two sources...

  13. Selenium in oncology: from chemistry to clinics.

    PubMed

    Micke, Oliver; Schomburg, Lutz; Buentzel, Jens; Kisters, Klaus; Muecke, Ralph

    2009-01-01

    The essential trace element selenium, which is a crucial cofactor in the most important endogenous antioxidative systems of the human body, is attracting more and more the attention of both laypersons and expert groups. The interest of oncologists mainly focuses in the following clinical aspects: radioprotection of normal tissues, radiosensitizing in malignant tumors, antiedematous effect, prognostic impact of selenium, and effects in primary and secondary cancer prevention. Selenium is a constituent of the small group of selenocysteine-containing selenoproteins and elicits important structural and enzymatic functions. Selenium deficiency has been linked to increased infection risk and adverse mood states. It has been shown to possess cancer-preventive and cytoprotective activities in both animal models and humans. It is well established that Se has a key role in redox regulation and antioxidant function, and hence in membrane integrity, energy metabolism and protection against DNA damage. Recent clinical trials have shown the importance of selenium in clinical oncology. Our own clinical study involving 48 patients suggest that selenium has a positive effect on radiation-associated secondary lymphedema in patients with limb edemas, as well as in the head and neck region, including endolaryngeal edema. Another randomized phase III study of our group was performed to examine the cytoprotective properties of selenium in radiation oncology. The aim was to evaluate whether sodium selenite is able to compensate a preexisting selenium deficiency and to prevent radiation induced diarrhea in adjuvant radiotherapy for pelvic gynecologic malignancies. Through this study, the significant benefits of sodium selenite supplementation with regards to selenium deficiency and radiotherapy induced diarrhea in patients with cervical and uterine cancer has been shown for the first time in a prospective randomized trial. Survival data imply that supplementation with selenium does not

  14. Think outside of the box: selenium volatilization altered by a broccoli gene in the ubiquinone biosynthetic pathway

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Selenium metabolism has been an area of active research because of the essentiality as well as toxicity of selenium to animals and humans. Biologically based selenium volatilization has been a particular area of interest for its potential in making detoxification of selenium pollution highly effecti...

  15. 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.

  16. Effects of Selenium-Enriched Protein from Ganoderma lucidum on the Levels of IL-1β and TNF-α, Oxidative Stress, and NF-κB Activation in Ovalbumin-Induced Asthmatic Mice

    PubMed Central

    Min-chang, Guan; Wei-hong, Tang; Zhen, Xu; Jie, Sun

    2014-01-01

    The purpose of this study was to compare the effect and toxicity of organic selenium (Pro-Se) with inorganic selenium (IOSe) in preventing asthma in ovalbumin-induced asthmatic mice. After the mice were treated orally with Pro-Se and IOSe, respectively, the plasma Se levels, Se accumulation in liver and kidney, tumor necrosis factor alpha (TNF-α), interleukin 1 beta (IL-1β), oxidative stress, and NF-κB activation in lung were examined. The results showed that the serumal Se levels in the mice fed the Pro-Se were significant (P < 0.01) elevations. It results in restoration of the level of endogenous antioxidant enzyme, lower levels of TNF-α and IL-1β, and activated NF-κB in the asthmatic mice. Our experiments have demonstrated profound differences between the activities of organic selenium and inorganic selenium in experimental conditions. These data provide an important proof of the concept that organic selenium might be a new potential therapy for the management of childhood asthma in humans. PMID:24660015

  17. Antifungal Activity of Selenium Nanoparticles Synthesized by Bacillus species Msh-1 Against Aspergillus fumigatus and Candida albicans

    PubMed Central

    Shakibaie, Mojtaba; Salari Mohazab, Naser; Ayatollahi Mousavi, Seyyed Amin

    2015-01-01

    Background: Fungal infections affect various parts of the body and can be difficult to treat. Aspergillus infection causes a spectrum of diverse diseases particularly in lung according to host immunity. The two major entities are invasive pulmonary aspergillosis and chronic pulmonary aspergillosis. Candida infections can be superficial or invasive. Superficial infections often affect the skin or mucous membranes. However, invasive fungal infections are often life-threatening. Advances in nanotechnology have opened new horizons in nanomedicine, allowing the synthesis of nanoparticles that can be assembled into complex architectures. Novel studies and technologies are devoted to understanding the mechanisms of disease for the design of new drugs. Objectives: In the present study, the antifungal activity of biogenic selenium nanoparticles (Se NPs) against Aspergillus fumigatus and Candida albicans was investigated. Materials and Methods: Se-reducing bacteria previously identified as Bacillus sp. MSh-1 were used for the intracellular biosynthesis of elemental Se NPs. The shape, size, and purity of the extracted NPs were determined with various instrumental techniques. The nanoparticles antifungal characterization mainly derives from the following pathways: (i) to generate sustained flux of nano-ions from the compounds that deposited on special substrates or imbedded in colloidal or semisolid matrices. (ii) To transport active those ions to sensitive targets on plasma membrane of fungi. Results: The results of energy-dispersive X-ray demonstrated that the purified NPs consisted of only Se. In addition, transmission electron micrographs showed that 120- to 140-nm spherical Se NPs were the most common. An antifungal assay was performed with a standard Clinical and Laboratory Standards Institute broth microdilution method. Minimum inhibitory concentration (MIC) measurements of the antifungal activity of the Se NPs against C. albicans (70 μg/mL) and A. fumigatus (100

  18. Selenium status affects selenoprotein expression, reproduction, and F₁ generation locomotor activity in zebrafish (Danio rerio).

    PubMed

    Penglase, Sam; Hamre, Kristin; Rasinger, Josef D; Ellingsen, Staale

    2014-06-14

    Se is an essential trace element, and is incorporated into selenoproteins which play important roles in human health. Mammalian selenoprotein-coding genes are often present as paralogues in teleost fish, and it is unclear whether the expression patterns or functions of these fish paralogues reflect their mammalian orthologues. Using the model species zebrafish (Danio rerio; ZF), we aimed to assess how dietary Se affects key parameters in Se metabolism and utilisation including glutathione peroxidase (GPX) activity, the mRNA expression of key Se-dependent proteins (gpx1a, gpx1b, sepp1a and sepp1b), oxidative status, reproductive success and F1 generation locomotor activity. From 27 d until 254 d post-fertilisation, ZF were fed diets with graded levels of Se ranging from deficient ( < 0·10 mg/kg) to toxic (30 mg/kg). The mRNA expression of gpx1a and gpx1b and GPX activity responded in a similar manner to changes in Se status. GPX activity and mRNA levels were lowest when dietary Se levels (0·3 mg/kg) resulted in the maximum growth of ZF, and a proposed bimodal mechanism in response to Se status below and above this dietary Se level was identified. The expression of the sepp1 paralogues differed, with only sepp1a responding to Se status. High dietary Se supplementation (30 mg/kg) decreased reproductive success, while the offspring of ZF fed above 0·3 mg Se/kg diet had lower locomotor activity than the other groups. Overall, the novel finding of low selenoprotein expression and activity coinciding with maximum body growth suggests that even small Se-induced variations in redox status may influence cellular growth rates. PMID:24666596

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

    SciTech Connect

    Yu, Huijun; Ge, Yan; Wang, Ying; Lin, Chi-Tsai; Li, Jing; Liu, Xiaoman; Zang, Tianzhu; Xu, Jiayun; Liu, Junqiu . E-mail: junqiuliu@jlu.edu.cn; Luo, Guimin; Shen, Jiacong

    2007-07-06

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

  20. Determination of selenium and its compounds in marine organisms.

    PubMed

    Bryszewska, Małgorzata Anita; Måge, Amund

    2015-01-01

    In this study, we investigate the type and quantity of selenium compounds in fish and marine organisms, using ion-pair reversed phase LC–ICP-MS, developed and applied for the analysis of Atlantic cod, Atlantic salmon, Greenland halibut, Atlantic herring, blue mussel, common crab, scallop, calanus, and Euphasia super. Of the samples examined, the lowest level of selenium was found in farmed Atlantic salmon (0.17 mg Se kg(−1) dm). The total selenium extraction efficiency by phosphate buffer was 2.5 times higher in sea plankton and shellfish samples than in fish samples. Analysis of Se species in each hydrolysate obtained by proteolysis showed the presence of selenomethionine, which constituted 41.5% of the selenium compounds detected in hydrolysates of Atlantic herring and 98.4% of those in extracts of Atlantic salmon. Inorganic compounds, such as selenates and selenites, were detected mainly in sea plankton and shellfish samples (<0.13 mg Se kg(−1) wm), although no correlation was found between the presence of inorganic compounds and total selenium concentration. The accuracy of the total selenium determination was validated using a certified reference material (oyster tissue (NIST 1566b)). A lyophilised powder of cod (Gadus morhua) was used to validate speciation analysis, enzymatic hydrolysis of lyophilised powder of cod recovered 54 ± 6% of total selenium, and SeMet constituted 83.5 ± 5.28% of selenium detected in hydrolysates. The chromatographic detection limits were, respectively, 0.30 ng mL(−1), 0.43 ng mL(−1), 0.54 ng mL(−1), 0.55 ng mL(−1), 0.57 ng mL(−1) and 0.72 ng mL(−1) for selenate, selenomethionine, selenite, Se-methyl-selenocysteine, selenocystine and selenomethionine selenoxide.The data on selenium concentrations and speciation presented here could be useful in estimating levels of selenium intake by seafood consumption. PMID:25468190

  1. Selective sorption behavior of iodine species on an activated carbon disk and its implication for the speciation analysis

    NASA Astrophysics Data System (ADS)

    Yoon, H.; Lee, J.; An, J.

    2013-12-01

    In recent times, iodate (IO3-) which can be generated under highly oxidized conditions such as the ozonation process in a water treatment plant has been receiving increasing attention due to its high toxicity to human and environment. In this respect, sorption behavior of iodide (I-) and IO3- on an activated carbon (AC) disk as a solid sorbent was investigated for the further development of efficient removal and analytical techniques. To this end, batch sorption tests were performed as a function of pH, sample volume, and initial concentration. Sorption of I- occurred preferentially on the surface of AC disk, regardless of pH levels (i.e., 4, 6, and 8). However, IO3- was quite sensitive to pH levels and the sorption capability of IO3- on the AC disk was much smaller than that of I-. Maximum sorption capacities of I- and IO3- in the different matrices (i.e., deionized water and seawater) were also assessed. In addition, the analytical strategy for the iodine speciation was also introduced. Iodine species were separated and pre-concentrated onto the AC disk based on their selective sorption properties according to the pH levels. Then, the AC disk pre-concentrated was directly analyzed using wavelength dispersive X-ray fluorescence spectrometry. Acknowledgement This research was supported by a grant from the Korea Basic Science Institute (project No. E33300).

  2. Synthesis and characterization of single crystalline selenium nanowire arrays

    SciTech Connect

    Zhang, X.Y. . E-mail: apzhxy@polyu.edu.hk; Xu, L.H.; Dai, J.Y.; Cai, Y.; Wang, N.

    2006-09-14

    Ordered selenium nanowire arrays with diameters about 40 nm have been fabricated by electrodeposition using anodic porous alumina templates. As determined by X-ray diffraction, Raman spectra, electron diffraction and high-resolution transmission electron microscopy, selenium nanowires have uniform diameters, which are fully controllable. Single crystalline trigonal selenium nanowires have been obtained after postannealing at 180 deg. C. These nanowires are perfect with a c-axis growth orientation. The optical absorption spectra reveal two types of electron transition activity.

  3. Selenium Poisoning of Wildlife and Western Agriculture: Cause and Effect

    SciTech Connect

    Korte, N.E.

    2000-02-01

    This project examined the hypothesis that selenium contamination is not the principal cause of the decline of endemic fish species in the Upper Colorado Basin. Activities employed to test this hypothesis included a reconnaissance of locations altered by recent road construction, a re-interpretation of available literature regarding selenium toxicity, and the interpretation of unpublished data obtained from the Upper Colorado Basin Fish Recovery Program. The project demonstrates that most of the evidence implicating selenium is circumstantial.

  4. Temporal measurements and kinetics of selenium release during coal combustion and gasification in a fluidized bed.

    PubMed

    Shen, Fenghua; Liu, Jing; Zhang, Zhen; Yang, Yingju

    2016-06-01

    The temporal release of selenium from coal during combustion and gasification in a fluidized bed was measured in situ by an on-line analysis system of trace elements in flue gas. The on-line analysis system is based on an inductively coupled plasma optical emission spectroscopy (ICP-OES), and can measure concentrations of trace elements in flue gas quantitatively and continuously. The results of on-line analysis suggest that the concentration of selenium in flue gas during coal gasification is higher than that during coal combustion. Based on the results of on-line analysis, a second-order kinetic law r(x)=0.94e(-26.58/RT)(-0.56 x(2) -0.51 x+1.05) was determined for selenium release during coal combustion, and r(x)=11.96e(-45.03/RT)(-0.53 x(2) -0.56 x+1.09) for selenium release during coal gasification. These two kinetic laws can predict respectively the temporal release of selenium during coal combustion and gasification with an acceptable accuracy. Thermodynamic calculations were conducted to predict selenium species during coal combustion and gasification. The speciation of selenium in flue gas during coal combustion differs from that during coal gasification, indicating that selenium volatilization is different. The gaseous selenium species can react with CaO during coal combustion, but it is not likely to interact with mineral during coal gasification. PMID:26897573

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

    PubMed Central

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

    2016-01-01

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

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

    PubMed

    Liu, Min; Jing, Huijuan; Zhang, Jianjun; Che, Gen; Zhou, Meng; Gao, Zheng; Li, Shangshang; Ren, Zhenzhen; Hao, Long; Liu, Yu; Jia, Le

    2016-01-01

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

  7. Antidiabetic activity of mycelia selenium-polysaccharide from Catathelasma ventricosum in STZ-induced diabetic mice.

    PubMed

    Liu, Yuntao; Sun, Jun; Rao, Shengqi; Su, Yujie; Li, Junhua; Li, Caiming; Xu, Shude; Yang, Yanjun

    2013-12-01

    Se-polysaccharide from Catathelasma ventricosum (SPC-2) was purified by DEAE-52 and Sephadex G-100 column chromatography. The average size of SPC-2 was 1.6×10(5) Da, and it was mainly composed of glucose (87.4%) with the conformation of β-pyran ring. The branched structure of SPC-2 was proved intuitively by atomic force microscope (AFM). The antidiabetic potential of SPC-2 was tested in STZ-induced diabetic mice. After STZ-induced diabetic mice being administered of SPC-2 for 30 days, SPC-2 treatment significantly reduced the levels of malondialdehyde (MDA) and low-density lipoprotein cholesterol (LDL-C) that were increased by the STZ treatment. Further, the SPC-2 treatment led to increased activity of antioxidant enzymes in liver and kidney and high-density lipoprotein cholesterol (HDL-C) that were decreased by the STZ. The results of histopathology also showed SPC-2 protected tissues (pancreas, liver and kidney) against peroxidation damage and maintained tissue integrity. PMID:24007742

  8. 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

  9. 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

  10. 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. PMID:25631289

  11. 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

  12. Green synthesis and structural characterization of selenium nanoparticles and assessment of their antimicrobial property.

    PubMed

    Srivastava, Nishant; Mukhopadhyay, Mausumi

    2015-09-01

    In the present study, selenium nanoparticles were biologically synthesized by non-pathogenic, economic and easy to handle bacterium Ralstonia eutropha. The selenium oxo anion was reduced to selenium nanoparticles in the presence of the bacterium. The bacterium was grown aerobically in the reaction mixture. An extracellular, stable, uniform, spherical selenium nanoparticle was biosynthesized. The TEM analysis revealed that the biosynthesized selenium nanoparticles were spherical in shape with size range of 40-120 nm. XRD and SAED analysis showed that nanocrystalline selenium of pure hexagonal phase was synthesized. The formation of actinomorphic trigonal selenium nanorods was also observed. A mechanism of biosynthesis of selenium nanoparticles by R. eutropha was proposed. The biosynthesized selenium nanoparticles were investigated for their antimicrobial activity against potential pathogens. Selenium nanoparticles showed excellent antimicrobial activity. The 100, 100, 250 and 100 µg/ml selenium nanoparticles were found to inhibit 99 % growth of Pseudomonas aeruginosa, Staphylococcus aureus, Escherichia coli and Streptococcus pyogenes, respectively. Similarly, the 500 µg/ml of selenium nanoparticles was found to inhibit the growth of pathogenic fungi Aspergillus clavatus. The antimicrobial efficacy of selenium nanoparticle was comparable with commercially available antibiotic drug Ampicillin. PMID:25972036

  13. Selenium in diet

    MedlinePlus

    ... please enable JavaScript. Selenium is an essential trace mineral. This means your body must get this mineral in the food you eat. Small amounts of ... for your health. Function Selenium is a trace mineral. Your body only needs it in small amounts. ...

  14. Enrichment of selenium in allium vegetables for cancer prevention.

    PubMed

    Ip, C; Lisk, D J

    1994-09-01

    We previously reported that garlic cultivated with selenium fertilization is superior to regular garlic in mammary cancer prevention in the rat 7,12-dimethylbenz[a]anthracene (DMBA) model (Nutr. Cancer, 17, 279-286, 1992). A new crop of high-selenium garlic was harvested in 1992 and was used in a dose-response study to confirm the reproducibility of the product and the bioassay. Supplementation of 1 or 2 p.p.m. Se in the diet from the high-selenium garlic produced a 56% or 75% reduction respectively in the total tumor yield. Since both garlic and onion belong to the same allium family of vegetables, we were also interested in finding out whether our experience with garlic could be similarly applied to onion. A high-selenium onion crop was grown in the same season and location and with the same schedule of selenium fertilization. Two distinct differences were noted with the high-selenium onion regarding its capacity to accumulate selenium and its efficacy in cancer prevention. First, the selenium concentration in onion was considerably lower (28 p.p.m. Se dry wt) as compared to that found in garlic (110-150 p.p.m. Se). Second, given the same levels of selenium supplementation, the high-selenium onion was apparently not as powerful as the high-selenium garlic in mammary cancer inhibition. Thus different plants, even those of the same genus, may respond in their unique way to selenium fertilization and the biological benefits of selenium enrichment may vary depending on the species. Additional information from our study indicated that the high-selenium garlic/onion might provide an ideal system for delivering selenium-substituted analogs in a food form for cancer prevention: (i) they expressed a good range of anticancer activity and could be easily adapted for human consumption on a regular basis; (ii) their ingestion did not result in an excessive accumulation of tissue selenium, a concern that is associated with the standard selenium compounds such as selenite and

  15. Selenium transformation in coal mine spoils: Its environmental impact assessment. Final report

    SciTech Connect

    Harness, J.; Atalay, A.; Koll, K.J.; Zhang, H.; Maggon, D.

    1991-12-31

    The objective of this program was to conduct an environmental impact assessment study for selenium from coal mine spoils. The use of in-situ lysimetry to predict selenium speciation, transformation, and mobility under natural conditions was evaluated. The scope of the study was to construct and test field-scale lysimeter and laboratory mini-column to assess mobility and speciation of selenium in coal mine overburden and soil systems; to conduct soil and groundwater sampling throughout the state of Oklahoma for an overall environmental impact assessment of selenium; and to conduct an in-depth literature review on the solubility, speciation, mobility, and toxicity of selenium from various sources. Groundwater and surface soil samples were also collected from each county in Oklahoma. Data collected from the lysimeter study indicated that selenium in the overburden of the abandoned mine site was mainly found in the selenite form. The amount of selenite found was too low and immobile to be of concern to the environment. The spoil had equilibrated long enough (over 50 years) that most of the soluble forms of selenium have already been lost. Examination of the overburden indicated the presence of pyrite crystals that precipitated over time. The laboratory mini-column study indicated that selenite is quite immobile and remained on the overburden material even after leaching with dilute acid. Data from groundwater samples indicated that based on the current permissible level for selenium in groundwater (0.01 mg Se/L), Oklahoma groundwater is widely contaminated with the element. However, according to the new regulation (0.05 mg Se/L), which is to be promulgated in 1992, only 9 of the 77 counties in the state exceed the limit.

  16. Selenium detoxification by volatilization and precipitation in aquatic plants

    SciTech Connect

    Fan, T.W.M.; Higashi, R.M.

    1995-12-31

    The narrow margin of requirement and toxicity for selenium makes it a difficult pollution problem to solve. Selenium bioaccumulation has been a major threat to wildlife in California and is becoming a major concern in the San Francisco Bay/Estuaries. Despite the past efforts in Se nutrition, chemistry, and remediation, its toxicity and detoxification mechanism(s) in wildlife, particularly primary producers, is still unclear, due to a lack of understanding in Se biochemistry. This is becoming a critical issue in assessing Se risk and remediation. To address this gap, the authors have been characterizing Se speciation and its linkage to detoxification mechanism(s) of two indigenous aquatic plants, duckweed (Lemna minor) and a microphyte (Chlorella). Using GT-MS analysis, they found that Chlorella monocultures transformed Se oxyanions into volatile dimethylselenide and dimethyidiselenide and into insoluble So at extremely high Se (up to 750 ppm) concentrations. This alga did not accumulate selenomethionine which is among the most toxic forms of Se to wildlife. Dimethylsulfide was also volatilized, consistent with the hypothesis that dimethylsulfide/dimethylselenide emissions share a similar biochemical pathway. Se-treated Chlorella biomass released dimethylsulfide/dimethylselenide upon alkaline hydrolysis, suggesting the presence of dimethylsulfonium and dimethylselenonium propionates. Dimethylsulfoniumpropionate is known as an osmoprotectant in marine phytoplankton and as a major contributor to global biogenic dimethylsulfide emissions. Dimethylselenoniumpropionate has not been identified previously and may be a byproduct of dimethylsulfoniumpropionate synthesis. The unusual Se tolerance of Chlorella may be due to its ability to volatilize and precipitate Se. Such activities may be utilized for in situ Se bioremediation. Similar investigations with duckweed is underway.

  17. Selenium biogeochemical cycling and fluxes in the hyporheic zone of a mining-impacted stream.

    PubMed

    Oram, Libbie L; Strawn, Daniel G; Morra, Matthew J; Möller, Gregory

    2010-06-01

    The influence of hyporheic exchange on selenium (Se) biogeochemistry and mobility in sediments is unknown. A multiscale investigation of Se biogeochemistry in the hyporheic zone of East Mill Creek (EMC), southeastern Idaho, USA, was performed using in situ surface water and pore water geochemical measurements, a field-based stream tracer test, and energy-dependent micro synchrotron X-ray fluorescence (mu-SXRF) measurements of Se speciation in sediments. The active hyporheic zone was determined to be 12 +/- 3 cm. Pore water redox profiles indicated that a transition to suboxic conditions begins at approximately 6 cm. Modeling pore water Se and solid phase analysis suggested Se uptake is occurring. Micro-SXRF analysis of sediments showed reduced elemental Se or selenides throughout the profile and selenite in surface sediments. Field geochemical measurements and microscale analysis both support the hypothesis that reduction in the hyporheic zone promotes sequestration of surface water Se. PMID:20443593

  18. Dietary selenium and selenoprotein function

    PubMed Central

    Weeks, Benjamin S.; Hanna, Mirna S.; Cooperstein, Deborah

    2012-01-01

    Summary Selenium is a trace mineral and an essential nutrient in the human diet. Selenium is found in soil and water and consequently enters the food chain through the root ways of plants and aquatic organisms. Some areas of the world are low in soil selenium resulting in a selenium deficient population and the appearance of an associated heart disease and bone disorders that can be corrected with dietary selenium. Indeed the requirement for dietary selenium was established by these observations and while selenium deficiency is rare in the West, patients requiring long-term intravenous feedings have also show heart disease associated with a deficiency of selenium in the feeding fluids. Subsequently, it has been established that dietary selenium can improve a wide range of human health conditions even in areas with soil replete in selenium. PMID:22847213

  19. 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. PMID:25593145

  20. SPECIATE - EPA'S DATABASE OF SPECIATED EMISSION PROFILES

    EPA Science Inventory

    SPECIATE is the U.S. Environmental Protection Agency's (EPA) repository of total organic compound (TOC) and particulate matter (PM) speciation profiles for emissions from air pollution sources. The data base has recently been updated and an associated report has recently been re...

  1. Correlation of volcanic activity with sulfur oxyanion speciation in a crater lake

    SciTech Connect

    Takano, B.

    1987-03-27

    The Yugama crater lake at Kusatsu-Shirane volcano, Japan, contains nearly 2200 tons (2800 parts per million) of polythionate ions (S/sub n/O/sub 6//sup 2 -/, where n = 4 to 9). Analytical data on lake water sampled before and during eruptions in 1982 showed that the concentrations of polythionates decreased and sulfate increased in response to the preeruption activities of the subaqueous fumaroles. These changes were observed 2 months before the first phreatic explosion on 26 October 1982. The monitoring of polythionates and sulfate in crater lake water is a promising means of anticipating potential volcanic eruption hazards.

  2. Inoculation of Astragalus racemosus and Astragalus convallarius with selenium-hyperaccumulator rhizosphere fungi affects growth and selenium accumulation.

    PubMed

    Lindblom, Stormy Dawn; Fakra, Sirine C; Landon, Jessica; Schulz, Paige; Tracy, Benjamin; Pilon-Smits, Elizabeth A H

    2013-03-01

    Little is known about how fungi affect plant selenium (Se) accumulation. Here we investigate the effects of two fungi on Se accumulation, translocation, and chemical speciation in the hyperaccumulator Astragalus racemosus and the non-accumulator Astragalus convallarius. The fungi, Alternaria astragali (A3) and Fusarium acuminatum (F30), were previously isolated from Astragalus hyperaccumulator rhizosphere. A3-inoculation enhanced growth of A. racemosus yet inhibited growth of A. convallarius. Selenium treatment negated these effects. F30 reduced shoot-to-root Se translocation in A. racemosus. X-ray microprobe analysis showed no differences in Se speciation between inoculation groups. The Astragalus species differed in Se localization and speciation. A. racemosus root-Se was distributed throughout the taproot and lateral root and was 90 % organic in the lateral root. The related element sulfur (S) was present as a mixture of organic and inorganic forms in the hyperaccumulator. Astragalus convallarius root-Se was concentrated in the extreme periphery of the taproot. In the lateral root, Se was exclusively in the vascular core and was only 49 % organic. These findings indicate differences in Se assimilation between the two species and differences between Se and S speciation in the hyperaccumulator. The finding that fungi can affect translocation may have applications in phytoremediation and biofortification. PMID:23117393

  3. Mineral Commodity Profiles: Selenium

    USGS Publications Warehouse

    Butterman, W.C.; Brown, R.D., Jr.

    2004-01-01

    Overview -- Selenium, which is one of the chalcogen elements in group 16 (or 6A) of the periodic table, is a semiconductor that is chemically similar to sulfur for which it substitutes in many minerals and synthetic compounds. It is a byproduct of copper refining and, to a much lesser extent, lead refining. It is used in many applications, the major ones being a decolorizer for glass, a metallurgical additive to free-machining varieties of ferrous and nonferrous alloys, a constituent in cadmium sulfoselenide pigments, a photoreceptor in xerographic copiers, and a semiconductor in electrical rectifiers and photocells. Refined selenium amounting to more than 1,800 metric tons (t) was produced by 14 countries in 2000. Japan, Canada, the United States, and Belgium, which were the four largest producers, accounted for nearly 85 percent of world production. An estimated 250 t of the world total is secondary selenium, which is recovered from scrapped xerographic copier drums and selenium rectifiers; the selenium in nearly all other uses is dissipated (not recoverable as waste or scrap). The present selenium reserve bases for the United States and the world (including the United States), which are associated with copper deposits, are expected to be able to satisfy demand for selenium for several decades without difficulty.

  4. Why Nature Chose Selenium.

    PubMed

    Reich, Hans J; Hondal, Robert J

    2016-04-15

    The authors were asked by the Editors of ACS Chemical Biology to write an article titled "Why Nature Chose Selenium" for the occasion of the upcoming bicentennial of the discovery of selenium by the Swedish chemist Jöns Jacob Berzelius in 1817 and styled after the famous work of Frank Westheimer on the biological chemistry of phosphate [Westheimer, F. H. (1987) Why Nature Chose Phosphates, Science 235, 1173-1178]. This work gives a history of the important discoveries of the biological processes that selenium participates in, and a point-by-point comparison of the chemistry of selenium with the atom it replaces in biology, sulfur. This analysis shows that redox chemistry is the largest chemical difference between the two chalcogens. This difference is very large for both one-electron and two-electron redox reactions. Much of this difference is due to the inability of selenium to form π bonds of all types. The outer valence electrons of selenium are also more loosely held than those of sulfur. As a result, selenium is a better nucleophile and will react with reactive oxygen species faster than sulfur, but the resulting lack of π-bond character in the Se-O bond means that the Se-oxide can be much more readily reduced in comparison to S-oxides. The combination of these properties means that replacement of sulfur with selenium in nature results in a selenium-containing biomolecule that resists permanent oxidation. Multiple examples of this gain of function behavior from the literature are discussed. PMID:26949981

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

    PubMed

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

    2011-10-01

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

  6. Effect of selenium supplementation in hypothyroid subjects of an iodine and selenium deficient area: the possible danger of indiscriminate supplementation of iodine-deficient subjects with selenium.

    PubMed

    Contempre, B; Dumont, J E; Ngo, B; Thilly, C H; Diplock, A T; Vanderpas, J

    1991-07-01

    Selenium and seleno dependent glutathione peroxidase (GPX) deficiency has been described in endemias of myxedematous cretinism. In northern Zaire, a selenium supplementation trial has been conducted. Beside correcting the GPX activity, two months of selenium supplementation was shown to modify the serum thyroid hormones parameters in clinically euthyroid subjects and to induce a dramatic fall of the already impaired thyroid function in clinically hypothyroid subjects. These results further support a role of selenium in thyroid hormone metabolism. In an iodine deficient area, this selenium deficiency could lead to opposite clinical consequences: protect the general population and the fetus against iodine deficiency and brain damage; and in turn, favour the degenerative process of the thyroid gland leading to myxoedematous cretinism. PMID:2045471

  7. Mercury speciation and dispersion from an active gold mine at the West Wits area, South Africa.

    PubMed

    Lusilao-Makiese, J G; Tessier, E; Amouroux, D; Tutu, H; Chimuka, L; Weiersbye, I; Cukrowska, E M

    2016-01-01

    Total mercury (HgTOT), inorganic mercury (IHg), and methylmercury (MHg) were determined in dry season waters, sediments, and tailings from an active mine which has long history of gold exploitation. Although HgTOT in waters was generally low (0.03 to 19.60 ng L(-1)), the majority of the samples had proportions of MHg of at least 90 % of HgTOT which denotes a substantial methylation potential of the mine watersheds. Mercury was relatively high in tailing materials (up to 867 μg kg(-1)) and also in the mine sediments (up to 837 μg kg(-1)) especially in samples collected near tailing storage facilities and within a receiving water dam. Sediment profiles revealed mercury enrichment and enhanced methylation rate at deeper layers. The presence of IHg and decaying plants (organic matter) in the watersheds as well as the anoxic conditions of bulk sediments are believed to be some of the key factors favoring the mercury methylation at the site. PMID:26687090

  8. Iron and phosphorus speciation in Fe-conditioned membrane bioreactor activated sludge.

    PubMed

    Wu, Hao; Ikeda-Ohno, Atsushi; Wang, Yuan; Waite, T David

    2015-06-01

    Iron dosing of membrane bioreactors (MBRs) is widely used as a means of meeting effluent phosphorus targets but there is limited understanding of the nature of iron and phosphorus-containing solids that are formed within the bioreactor (an important issue in view of the increasing interest in recovering phosphorus from wastewaters). Of particular challenge is the complexity of the MBR system and the variety of reactions that can occur on addition of iron salts to a membrane bioreactor. In this study, the performances of bench scale MBRs with dosing of either ferrous or ferric salts were monitored for a period of four months. The distributions of Fe and P-species in the Fe-conditioned sludges were determined using X-ray absorption spectroscopy (XAS) at the Fe K-edge and the P K-edge. Regardless of whether iron was dosed to the anoxic or aerobic chambers and regardless of whether ferrous (Fe(II)) or ferric (Fe(III)) iron was dosed, iron present in the minerals in the conditioned sludges was consistently in the +III oxidation state. Fitting of the Fe K-edge EXAFS spectra revealed that an Fe(III)-phosphate species was the main Fe species present in all cases with the remaining fraction dominated by lepidocrocite (γ-FeOOH) in the Fe(II)-dosed case and ferrihydrite (am-FeOOH) in the Fe(III)-dosed case. Approximately half the phosphorus in the activated sludge samples was present as a distinct Fe-PO4 mineral (such as strengite or an amorphous ferric hydroxyl phosphate analogue of strengite) and half as phosphorus adsorbed to an iron oxyhydroxide mineral phase indicating that both co-precipitation and adsorption of phosphorus by iron contribute to removal of phosphorus from the MBR supernatant. PMID:25900910

  9. ASSESSING SPECIATION AND RELEASE OF HEAVY METALS FROM COAL COMBUSTION PRODUCTS

    EPA Science Inventory

    In this study, the speciation of heavy metals such as arsenic, selenium, lead, zinc and mercury in coal combustion products (CCPs) was evaluated using sequential extraction procedures. Coal fly ash, bottom ash and flue gas desulphurization (FGD) sludge samples were used in the ex...

  10. Inverse association between gluthathione peroxidase activity and both selenium-binding protein 1 levels and gleason score in human prostate tissue

    Technology Transfer Automated Retrieval System (TEKTRAN)

    BACKGROUND. Data from human epidemiological studies, cultured mammalian cells, and animal models have supported a potentially beneficial role of selenium (Se) in prostate cancer prevention. In addition, Se-containing proteins including members of the gutathione peroxidase (GPx) family and Selenium-B...

  11. Conserved sequences of sperm-activating peptide and its receptor throughout evolution, despite speciation in the sea star Asterias amurensis and closely related species.

    PubMed

    Nakachi, Mia; Hoshi, Motonori; Matsumoto, Midori; Moriyama, Hideaki

    2008-08-01

    The asteroidal sperm-activating peptides (asterosaps) from the egg jelly bind to their sperm receptor, a membrane-bound guanylate cyclase, on the tail to activate sperm in sea stars. Asterosaps are produced as single peptides and then cleaved into shorter peptides. Sperm activation is followed by the acrosome reaction, which is subfamily specific. In order to investigate the molecular details of the asterosap-receptor interaction, corresponding cDNAs have been cloned, sequenced and analysed from the Asteriinae subfamily including Asterias amurensis, A. rubens, A. forbesi and Aphelasterias japonica, as well as Distolasterias nipon from the Coscinasteriinae subfamily. Averages of 29% and 86% identity were found from the deduced amino acid sequences in asterosap and its receptor extracellular domains, respectively, across all species examined. The phylogenic tree topology for asterosap and its receptor was similar to that of the mitochondrial cytochrome c oxidase subunit I. In spite of a certain homology, the amino acid sequences exhibited speciation. Conservation was found in the asterosap residues involved in disulphide bonding and proteinase-cleaving sites. Conversely, similarities were detected between potential asterosap-binding sites and the structure of the atrial natriuretic peptide receptor. Although the sperm-activating peptide and its receptor share certain common sequences, they may serve as barriers that ensure speciation in the sea star A. amurensis and closely related species. PMID:18578950

  12. Interaction between mercury (Hg), arsenic (As) and selenium (Se) affects the activity of glutathione S-transferase in breast milk; possible relationship with fish and sellfish intake.

    PubMed

    Gaxiola-Robles, Ramón; Labrada-Martagón, Vanessa; Celis de la Rosa, Alfredo de Jesús; Acosta-Vargas, Baudilio; Méndez-Rodríguez, Lía Celina; Zenteno-Savín, Tania

    2014-01-01

    Breast milk is regarded as an ideal source of nutrients for the growth and development of neonates, but it can also be a potential source of pollutants. Mothers can be exposed to different contaminants as a result of their lifestyle and environmental pollution. Mercury (Hg) and arsenic (As) could adversely affect the development of fetal and neonatal nervous system. Some fish and shellfish are rich in selenium (Se), an essential trace element that forms part of several enzymes related to the detoxification process, including glutathione S-transferase (GST). The goal of this study was to determine the interaction between Hg, As and Se and analyze its effect on the activity of GST in breast milk. Milk samples were collected from women between day 7 and 10 postpartum. The GST activity was determined spectrophotometrically; total Hg, As and Se concentrations were measured by atomic absorption spectrometry. To explain the possible association of Hg, As and Se concentrations with GST activity in breast milk, generalized linear models were constructed. The model explained 44% of the GST activity measured in breast milk. The GLM suggests that GST activity was positively correlated with Hg, As and Se concentrations. The activity of the enzyme was also explained by the frequency of consumption of marine fish and shellfish in the diet of the breastfeeding women. PMID:25208800

  13. Selenium or no selenium--that is the question in tumor patients: a new controversy.

    PubMed

    Muecke, Ralph; Schomburg, Lutz; Buentzel, Jens; Kisters, Klaus; Micke, Oliver

    2010-06-01

    The essential trace element selenium, which is a crucial cofactor in the most important endogenous antioxidative systems of the human body, is attracting more attention from both laypersons and expert groups. The interest of oncologists mainly focuses on the following clinical aspects: protection of normal tissues, sensitizing in malignant tumors, antiedematous effect, prognostic impact of selenium, and effects in primary and secondary cancer prevention. Selenium is a constituent of the small group of selenocysteine-containing selenoproteins and elicits important structural and enzymatic functions. Selenium deficiency has been linked to increased infection risk and adverse mood states. It has been shown to possess cancer-preventive and cytoprotective activities in both animal models and humans. It is well established that it has a key role in redox regulation and antioxidant function, and hence in membrane integrity, energy metabolism, and protection against DNA damage. Recent clinical trials have shown the importance of selenium in clinical oncology. In 2009, a significant benefit of sodium selenite supplementation-with no protection of tumor cells, which is often suspected by oncologists- was shown in a prospective randomized trial in gynecologic cancer patients undergoing radiation therapy. More recently, concerns arose from 2 large clinical prevention trials (NPC, SELECT) that selenium may increase the risk of developing type 2 diabetes. Despite obvious flaws in both studies and good counterarguments, controversy remains on the possible advantages and risks of selenium in cancer prevention. However, in the light of the recent clinical trials the potential benefits of selenium supplementation in tumor patients are becoming obvious, even though further research is needed. PMID:20462857

  14. Microbial Transformations of Selenium Species of Relevance to Bioremediation.

    PubMed

    Eswayah, Abdurrahman S; Smith, Thomas J; Gardiner, Philip H E

    2016-08-15

    Selenium species, particularly the oxyanions selenite (SeO3 (2-)) and selenate (SeO4 (2-)), 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

  15. Iodine and selenium deficiency associated with cretinism in northern Zaire.

    PubMed

    Vanderpas, J B; Contempré, B; Duale, N L; Goossens, W; Bebe, N; Thorpe, R; Ntambue, K; Dumont, J; Thilly, C H; Diplock, A T

    1990-12-01

    Selenium status was determined in an endemic-goiter area and in a control area of Zaire. Compared with the reference values of a noniodine-deficient area, serum selenium in subjects living in the core of the northern Zaire endemic-goiter belt (Karawa villages) was seven times lower in 52 school-children and similarly low in 23 cretins; erythrocyte glutathione peroxidase (RBC-GPX) was five times lower in schoolchildren and still two times lower in cretins (P = 0.004). In a less severely iodine-deficient city of the same endemia (Businga), selenium status was moderately altered. RBC-GPX activity was linearly associated with serum selenium concentration up to a value of 1140 nmol/L and leveled off at approximately 15 U/g Hb at greater selenium concentration. At Karawa villages, selenium supplementation normalized both the serum selenium and the RBC-GPX. This combined iodine and selenium deficiency could be associated with the elevated frequency of endemic myxedematous cretinism in Central Africa. PMID:2239787

  16. Selenium: finding the delicate balance

    SciTech Connect

    McBride, J.

    1987-01-01

    A deficiency of selenium can lead to the degeneration of heart muscle in children. Yet, an excess of selenium can produce a garlicky breath, and extreme levels can cause a loss of nails and hair. People get adequate selenium in their diets in North America, but there are areas around the world where the people exist on foods containing little or no selenium. A person is said to be in balance when the daily intake of selenium equals the amount excreted. However, the need for the mineral varies depending on the population, as well as the sex, studied. For example, Chinese men living in a selenium-deficient area need only 10 micrograms a day to maintain their body stores of selenium, whereas US men need 80 micrograms. In addition, there is a difference in how the body treats different forms and sources of selenium. The body absorbs the mineral better from plant sources than from animal sources, in many instances.

  17. A Single Amino Acid Difference between Mouse and Human 5-Lipoxygenase Activating Protein (FLAP) Explains the Speciation and Differential Pharmacology of Novel FLAP Inhibitors.

    PubMed

    Blevitt, Jonathan M; Hack, Michael D; Herman, Krystal; Chang, Leon; Keith, John M; Mirzadegan, Tara; Rao, Navin L; Lebsack, Alec D; Milla, Marcos E

    2016-06-10

    5-Lipoxygenase activating protein (FLAP) plays a critical role in the metabolism of arachidonic acid to leukotriene A4, the precursor to the potent pro-inflammatory mediators leukotriene B4 and leukotriene C4 Studies with small molecule inhibitors of FLAP have led to the discovery of a drug binding pocket on the protein surface, and several pharmaceutical companies have developed compounds and performed clinical trials. Crystallographic studies and mutational analyses have contributed to a general understanding of compound binding modes. During our own efforts, we identified two unique chemical series. One series demonstrated strong inhibition of human FLAP but differential pharmacology across species and was completely inactive in assays with mouse or rat FLAP. The other series was active across rodent FLAP, as well as human and dog FLAP. Comparison of rodent and human FLAP amino acid sequences together with an analysis of a published crystal structure led to the identification of amino acid residue 24 in the floor of the putative binding pocket as a likely candidate for the observed speciation. On that basis, we tested compounds for binding to human G24A and mouse A24G FLAP mutant variants and compared the data to that generated for wild type human and mouse FLAP. These studies confirmed that a single amino acid mutation was sufficient to reverse the speciation observed in wild type FLAP. In addition, a PK/PD method was established in canines to enable preclinical profiling of mouse-inactive compounds. PMID:27129215

  18. Activity of Selected Antioxidant Enzymes, Selenium Content and Fatty Acid Composition in the Liver of the Brown Hare (Lepus europaeus L.) in Relation to the Season of the Year.

    PubMed

    Drozd, Radosław; Pilarczyk, Renata; Pilarczyk, Bogumiła; Drozd, Arleta; Tomza-Marciniak, Agnieszka; Bombik, Teresa; Bąkowska, Małgorzata; Bombik, Elżbieta; Jankowiak, Dorota; Wasak, Agata

    2015-12-01

    The aim of the study was to evaluate the effect of low concentrations of selenium in the environment on the activity of selected antioxidant enzymes: Se-GSHPx, total GSHPx, SOD, CAT, and GST as well as fatty acid profile in the livers of brown hares during winter and spring. Liver tissues obtained from 20 brown hares collected in the north-eastern Poland in the winter and spring season were analyzed. In the tissue analyzed, a significantly lower level of selenium was noticeable in the spring compared to winter; however, values measured in both seasons indicated a deficiency of this element in the analyzed population of brown hares. There were no differences found that could indicate the influence of Se deficiency on the activity of antioxidant enzymes. The determined activity of antioxidant enzymes and fatty acid composition suggest a negligible impact of the low concentration of Se on the analyzed biochemical parameters of brown hare livers. PMID:26043915

  19. Percutaneous absorption of selenium sulfide

    SciTech Connect

    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 not 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.

  20. Male golden hamster in male reproductive toxicology testing: Assessment of protective activity of selenium in acute cadmium intoxication

    SciTech Connect

    Wiodarczyk, B.; Biernacki, B.; Minta, M.; Juszkiewicz, T.; Kozaczynski, W.

    1995-06-01

    The golden hamster has a short history as a laboratory animal. In spite of this, it has been extensively used as a subject for biomedical research. The hamster has also been utilized in toxicological evaluations, especially in teratology studies. Results of these investigations reveal that laboratory hamsters are very sensitive to many chemical compounds, including: drugs, food additives, industrial chemicals, heavy metals, and other environmental contaminants. The animals most frequently used in toxicological investigations are rats and mice. This is also true in male reproductive toxicology. Apparent differences in species sensitivity to chemical compounds suggest a need to examine a new species in this field of toxicology. A good example of chemical specific differences in species sensitivity is the testicular toxicity of 1,2-dibromo-3-chloropropane (DBCP), which was a testicular toxicant in humans and in rats, but it was not effective, even at relatively high dose levels, in the mouse. From our own vast experience in using hamsters in toxicological studies, we decided to use this laboratory animal in male reproductive toxicology screening tests. The purpose of this study was to determine the suitability of golden hamsters as an experimental animal species for male reproductive toxicology testing. To this effect we have chosen selenium and cadmium as test agents as they were well known for their spectacular effect on the male reproductive system. 13 refs., 1 tab.

  1. Regulation of hepatic carbohydrate metabolism by Selenium during diabetes.

    PubMed

    Chen, Hongping; Qiu, Qinqin; Zou, Caiyan; Dou, Lianjun; Liang, Jun

    2015-05-01

    In the present study, we have tried to unravel the role of Selenium supplementation in containing hyperglycemia by regulating enzymes activities involved in carbohydrate metabolism in liver of diabetic animals. Male wistar rats were divided into four groups: normal control, diabetic, Selenium treated control and Selenium treated diabetic group. Diabetes was induced in the animals by injecting alloxan intraperitoneally at a dose level of 150 mg/kg body weight. Selenium in the form of sodium selenite was supplemented to rats at a dose level of 1 PPM in drinking water, ad libitum for two time durations of 2 and 4 weeks. Animals were sacrificed and livers were excised for the analyses of enzymes involved in carbohydrate metabolism as well as the levels of glycogen. In-vitro (14)C-d glucose uptake and its turnover were also assessed in liver slices of all the treatment groups using radiorespirometry. Selenium supplementation to the diabetic rats normalized the enzyme activities of glucose-6-phosphatase, lactate dehydrogenase and glycogen phosphorylase as well as restored the glycogen levels to within the normal limits which were altered during diabetes. Interestingly, when Selenium was supplemented to diabetic rats, (14)C-d glucose uptake and its turnover showed a statistically significant increase in their values which however, were decreased in diabetic rats. In conclusion, Selenium mediates insulin-like role during diabetes by tending to normalize the altered activities of glucose metabolizing enzymes and also improves the glucose uptake and its metabolism by the liver. PMID:25779343

  2. Genetic Determinants of Responses to Selenium Supplementation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In a cohort of healthy adults (106 M, 155 W) in eastern North Dakota, we determined the relationships of five biomarkers of selenium (Se) status (plasma Se, serum selenoprotein P [SePP], plasma glutathione peroxidase [GPX3] activity, buccal cell Se, urine Se) to genotype for four selenoproteins (cyt...

  3. Selenium isotope analysis

    SciTech Connect

    Webster, C.L. Jr.; Warren, C.G.

    1981-01-01

    The isotope ratio of selenium-80 to selenium-74 was determined on an isotope ratio mass spectrometer. Samples of 2 to 4 mg of selenium were fluorinated with CoF/sub 3/ in a small disposable copper bomb. The product, SeF/sub 6/, was purified in a vacuum line by distillation. The /sup 80/Se//sup 74/Se ratio was determined on a double-collector mass spectrometer that was modified to collect either /sup 82/Se-/sup 80/Se or /sup 80/Se-/sup 74/Se ion pairs. The standard deviation of the difference between two individually fluorinated samples was about 1 per mil. Because essentially all the error was associated with the fluorination step, comparisons between a standard of SeF/sub 6/ and individually fluorinated samples can be expected to have a standard deviation of about 0.5 per mil.

  4. 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

  5. Simulation of the potential effects of CO2 leakage from carbon capture and storage activities on the mobilization and speciation of metals.

    PubMed

    de Orte, Manoela Romanó; Sarmiento, Aguasanta M; DelValls, T Ángel; Riba, Inmaculada

    2014-09-15

    One of the main risks associated with carbon capture and storage (CCS) activities is the leakage of the stored CO2, which can result in several effects on the ecosystem. Laboratory-scale experiments were performed to provide data on the possible effects of CO2 leakage from CCS on the mobility of metals previously trapped in sediments. Metal-contaminated sediments were collected and submitted to acidification by means of CO2 injection using different pH treatments. The test lasted 10 days, and samples were collected at the beginning and at the end of the experiment for metal analysis. The results revealed increases in the mobility of metals such as Co, Cu, Fe, Pb and Zn due to pH decreases. Geochemical modeling demonstrated that acidification influenced the speciation of the metals, increasing the concentrations of their free forms. These data suggest the possible sediment contamination consequences of accidental CO2 leakage during CCS activities. PMID:25125286

  6. Environmental speciation of actinides.

    PubMed

    Maher, Kate; Bargar, John R; Brown, Gordon E

    2013-04-01

    Although minor in abundance in Earth's crust (U, 2-4 ppm; Th, 10-15 ppm) and in seawater (U, 0.003 ppm; Th, 0.0007 ppm), light actinides (Th, Pa, U, Np, Pu, Am, and Cm) are important environmental contaminants associated with anthropogenic activities such as the mining and milling of uranium ores, generation of nuclear energy, and storage of legacy waste resulting from the manufacturing and testing of nuclear weapons. In this review, we discuss the abundance, production, and environmental sources of naturally occurring and some man-made light actinides. As is the case with other environmental contaminants, the solubility, transport properties, bioavailability, and toxicity of actinides are dependent on their speciation (composition, oxidation state, molecular-level structure, and nature of the phase in which the contaminant element or molecule occurs). We review the aqueous speciation of U, Np, and Pu as a function of pH and Eh, their interaction with common inorganic and organic ligands in natural waters, and some of the common U-containing minerals. We also discuss the interaction of U, Np, Pu, and Am solution complexes with common Earth materials, including minerals, colloids, gels, natural organic matter (NOM), and microbial organisms, based on simplified model system studies. These surface interactions can inhibit (e.g., sorption to mineral surfaces, formation of insoluble biominerals) or enhance (e.g., colloid-facilitated transport) the dispersal of light actinides in the biosphere and in some cases (e.g., interaction with dissimilatory metal-reducing bacteria, NOM, or Mn- and Fe-containing minerals) can modify the oxidation states and, consequently, the behavior of redox-sensitive light actinides (U, Np, and Pu). Finally, we review the speciation of U and Pu, their chemical transformations, and cleanup histories at several U.S. Department of Energy field sites that have been used to mill U ores, produce fissile materials for reactors and weapons, and store

  7. Biofunctionalization of Selenium Nanoparticle with Dictyophora Indusiata Polysaccharide and Its Antiproliferative Activity through Death-Receptor and Mitochondria-Mediated Apoptotic Pathways.

    PubMed

    Liao, Wenzhen; Yu, Zhiqiang; Lin, Zehua; Lei, Zhuogui; Ning, Zhengxiang; Regenstein, Joe M; Yang, Jiguo; Ren, Jiaoyan

    2015-01-01

    Bio-functionalized nanoparticles with semiconducting/metallic core encapsulated in a bio- or bio-derived materials are promising for applications in biology and especially in cancer diagnostic and healing. In this report, we report a facile, single-step, first-time synthesis and in-situ functionalization strategy for the preparation of monodispersed selenium nanoparticles (SeNPs) functionalized using a novel polysaccharide (DP1) extracted from Dictyophora indusiata (a fungus). The DP1 functionalized SeNPs (DP1-SeNPs), where DP1 is attached to the surface via Se-O bond as well as physic-sorption had, an average diameter of 89 nm, and were highly uniform, extremely stable compared to bare SeNPs. Detailed investigation of the biological properties of DP1-SeNP illustrated that they exhibit unprecedented, enhanced, and selective antiproliferative activity through inducing cell apoptosis confirmed by nuclear condensation, DNA cleavage, and accumulation of S phase cell arrest. The mechanism of the induced apoptosis was found to be a combination of the activation of caspases 3, 8, and 9, the Fas-associated death domain protein (FADD), reactive oxygen species (ROS) overproduction, as well as mitochondrial dysfunction. It is envisioned that the reported DP1-SeNPs will offer a new phase space for high-efficiency anticancer treatment with little side effect. PMID:26686000

  8. Biofunctionalization of Selenium Nanoparticle with Dictyophora Indusiata Polysaccharide and Its Antiproliferative Activity through Death-Receptor and Mitochondria-Mediated Apoptotic Pathways

    PubMed Central

    Liao, Wenzhen; Yu, Zhiqiang; Lin, Zehua; Lei, Zhuogui; Ning, Zhengxiang; Regenstein, Joe M.; Yang, Jiguo; Ren, Jiaoyan

    2015-01-01

    Bio-functionalized nanoparticles with semiconducting/metallic core encapsulated in a bio- or bio-derived materials are promising for applications in biology and especially in cancer diagnostic and healing. In this report, we report a facile, single-step, first-time synthesis and in-situ functionalization strategy for the preparation of monodispersed selenium nanoparticles (SeNPs) functionalized using a novel polysaccharide (DP1) extracted from Dictyophora indusiata (a fungus). The DP1 functionalized SeNPs (DP1-SeNPs), where DP1 is attached to the surface via Se-O bond as well as physic-sorption had, an average diameter of 89 nm, and were highly uniform, extremely stable compared to bare SeNPs. Detailed investigation of the biological properties of DP1-SeNP illustrated that they exhibit unprecedented, enhanced, and selective antiproliferative activity through inducing cell apoptosis confirmed by nuclear condensation, DNA cleavage, and accumulation of S phase cell arrest. The mechanism of the induced apoptosis was found to be a combination of the activation of caspases 3, 8, and 9, the Fas-associated death domain protein (FADD), reactive oxygen species (ROS) overproduction, as well as mitochondrial dysfunction. It is envisioned that the reported DP1-SeNPs will offer a new phase space for high-efficiency anticancer treatment with little side effect. PMID:26686000

  9. Aquatic selenium pollution is a global environmental safety issue.

    PubMed

    Lemly, A Dennis

    2004-09-01

    Selenium pollution is a worldwide phenomenon and is associated with a broad spectrum of human activities, ranging from the most basic agricultural practices to the most high-tech industrial processes. Consequently, selenium contamination of aquatic habitats can take place in urban, suburban, and rural settings alike--from mountains to plains, from deserts to rainforests, and from the Arctic to the tropics. Human activities that increase waterborne concentrations of selenium are on the rise and the threat of widespread impacts to aquatic life is greater than ever before. Important sources of selenium contamination in aquatic habitats are often overlooked by environmental biologists and ecological risk assessors due to preoccupation with other, higher priority pollutants, yet selenium may pose the most serious long-term risk to aquatic habitats and fishery resources. Failure to include selenium in the list of constituents measured in contaminant screening/monitoring programs is a major mistake, both from the hazard assessment aspect and from the pollution control aspect. Once selenium contamination begins, a cascade of bioaccumulation events is set into motion which makes meaningful intervention nearly impossible. However, this cascade of events need not happen if adequate foresight and planning are exercised. Early evaluation and action are key. Prudent risk management based on environmentally sound hazard assessment and water quality goals can prevent biological impacts. PMID:15261722

  10. Biomarkers of Selenium Status

    PubMed Central

    Combs, Gerald F.

    2015-01-01

    The essential trace element, selenium (Se), has multiple biological activities, which depend on the level of Se intake. Relatively low Se intakes determine the expression of selenoenzymes in which it serves as an essential constituent. Higher intakes have been shown to have anti-tumorigenic potential; and very high Se intakes can produce adverse effects. This hierarchy of biological activities calls for biomarkers informative at different levels of Se exposure. Some Se-biomarkers, such as the selenoproteins and particularly GPX3 and SEPP1, provide information about function directly and are of value in identifying nutritional Se deficiency and tracking responses of deficient individuals to Se-treatment. They are useful under conditions of Se intake within the range of regulated selenoprotein expression, e.g., for humans <55 μg/day and for animals <20 μg/kg diet. Other Se-biomarkers provide information indirectly through inferences based on Se levels of foods, tissues, urine or feces. They can indicate the likelihood of deficiency or adverse effects, but they do not provide direct evidence of either condition. Their value is in providing information about Se status over a wide range of Se intake, particularly from food forms. There is need for additional Se biomarkers particularly for assessing Se status in non-deficient individuals for whom the prospects of cancer risk reduction and adverse effects risk are the primary health considerations. This would include determining whether supranutritional intakes of Se may be required for maximal selenoprotein expression in immune surveillance cells. It would also include developing methods to determine low molecular weight Se-metabolites, i.e., selenoamino acids and methylated Se-metabolites, which to date have not been detectable in biological specimens. Recent analytical advances using tandem liquid chromatography-mass spectrometry suggest prospects for detecting these metabolites. PMID:25835046

  11. SPECIATE 4.2: speciation Database Development Documentation

    EPA Science Inventory

    SPECIATE is the U.S. Environmental Protection Agency's (EPA) repository of volatile organic gas and particulate matter (PM) speciation profiles of air pollution sources. Among the many uses of speciation data, these source profiles are used to: (1) create speciated emissions inve...

  12. Selenium and Methionine Sulfoxide Reduction.

    PubMed

    Gladyshev, Vadim N

    2014-10-01

    Selenium is an essential trace element because it is present in proteins in the form of selenocysteine residue. Functionally characterized selenoproteins are oxidoreductases. Selenoprotein methionine-R-sulfoxide reductase B1 (MsrB1) is a repair enzyme that reduces ROS-oxidized methionine residues in proteins. Here, we explored a possibility that reversible methionine oxidation is also a mechanism that regulates protein function. We found that MsrB1, together with Mical proteins, regulated mammalian actin assembly via stereospecific methionine oxidation and reduction in a reversible, site-specific manner. Two methionine residues in actin were specifically converted to methionine-R-sulfoxide by Mical1 and Mical2 and reduced back to methionine by MsrB1, supporting actin disassembly and assembly, respectively. Macrophages utilized this redox control during cellular activation by stimulating MsrB1 expression and activity. Thus, we identified the regulatory role of MsrB1 as a Mical antagonist in orchestrating actin dynamics and macrophage function. More generally, our study showed that proteins can be regulated by reversible site-specific methionine-R-sulfoxidation and that selenium is involved in this regulation by being a catalytic component of MsrB1. PMID:26461418

  13. Influence of the hydration by the environmental humidity on the metallic speciation and the photocatalytic activity of Cr/MCM-41

    NASA Astrophysics Data System (ADS)

    Elías, Verónica R.; Sabre, Ema V.; Winkler, Elin L.; Andrini, Leandro; Requejo, Félix G.; Casuscelli, Sandra G.; Eimer, Griselda A.

    2014-05-01

    The influence of the environmental humidity on the Cr species deposited on inorganic supports like MCM-41 silicates was analyzed by UV-vis Diffuse Reflectance (UV-vis RD), Electronic Spin Resonance (ESR) and X-ray near-edge (XANES) spectroscopy. Metal speciation could be inferred, finding that prolonged exposure periods under environmental humidity provoked the reduction of the active Cr6+ species and thus, the decrease of the Cr/MCM-41 photoactivity. After the Ti loading over the Cr modified samples, Cr species and the photoactivity were not notably influenced by the humidity exposure. Thus, it could be concluded that the presence of Ti is important because the TiO2 cover protects the oxidized Cr species, stabilizing them.

  14. Selenium-Containing Phycocyanin from Se-Enriched Spirulina platensis Reduces Inflammation in Dextran Sulfate Sodium-Induced Colitis by Inhibiting NF-κB Activation.

    PubMed

    Zhu, Chenghui; Ling, Qinjie; Cai, Zhihui; Wang, Yun; Zhang, Yibo; Hoffmann, Peter R; Zheng, Wenjie; Zhou, Tianhong; Huang, Zhi

    2016-06-22

    Selenium (Se) plays an important role in fine-tuning immune responses. Inflammatory bowel disease (IBD) involves hyperresponsive immunity of the digestive tract, and a low Se level might aggravate IBD progression; however, the beneficial effects of natural Se-enriched diets on IBD remain unknown. Previously, we developed high-yield Se-enriched Spirulina platensis (Se-SP) as an excellent organic nutritional Se source. Here we prepared Se-containing phycocyanin (Se-PC) from Se-SP and observed that Se-PC administration effectively reduced the extent of colitis in mouse induced by dextran sulfate sodium. Supplementation with Se-PC resulted in significant protective effects, including mitigation of body weight loss, bloody diarrhea, and colonic inflammatory damage. The anti-inflammatory effects of Se-PC supplementation were found to involve modulation of cytokines, including IL-6, TNF-α, MCP-1, and IL-10. Mechanistically, Se-PC inhibited the activation of macrophages by suppressing the nuclear translocation of NF-κB, which is involved in the transcription of these pro-inflammatory cytokines. These results together suggest potential benefits of Se-PC as a functional Se supplement to reduce the symptoms of IBD. PMID:27223481

  15. Selenium Treatment Technologies

    EPA Science Inventory

    Selenium (Se) is a metalloid that is a dietary requirement in small quantities, but toxic at higher quantities. It also is known to bioaccumulate. In oxic environments, it exists as selenate (+6) and selenite (+4), both of which are soluble. Selenite will sorb more strongly to...

  16. Selenium and Compounds

    Integrated Risk Information System (IRIS)

    Selenium and Compounds ; CASRN 7782 - 49 - 2 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcin

  17. Acute selenium toxicosis in sheep

    SciTech Connect

    Blodgett, D.J.

    1983-01-01

    The toxicity, toxicokinetics, and progressive pathological changes produced by sodium selenite in sheep following parenteral administration were evaluated. In the intramuscular study, the LD/sub 50/ for sodium selenite was 0.7 mg selenium/kg body weight. In the continuous intravenous infusion study, a gradient of tissue selenium/kg body weight with a standard error of 0.035 over a 192 hour observation period. The most evident clinical signs were dyspnea and depression . At necropsy, the most consistent lesions were edematous lungs and pale mottled hearts. Highest tissue selenium concentrations in declining order were found in the liver, kidney, and heart. Four sheep injected intravenously with 0.7 mg selenium/kg body weight survived the 192 hour post-injection observation period. Semilogarithmic plots of blood selenium concentration versus time were triphasic. The ..cap alpha.. and ..gamma.. rate constants of sheep administered a single dose of selenium intravenously were significantly greater than those obtained when sheep were injected intramuscularly with 0.7 mg selenium concentrations was attained with 4, 8, and 12 hour infusions at steady state concentrations of 2500, 3000, and 3500 ppb selenium in the blood. The heart was the target organ of acute selenium toxicosis. A dose-response relationship was observed in the heart with degeneration evident in all hearts and necrosis present in the 2 hearts with the highest concentrations of selenium.

  18. Immunomodulatory effect of selenosemicarbazides and selenium inorganic compounds, distribution in organs after selenium supplementation.

    PubMed

    Musik, I; Koziol-Montewka, M; Toś-Luty, S; Pasternak, K; Latuszyńska, J; Tokarska, M; Kielczykowska, M

    1999-12-01

    Antioxidant properties of selenium producing a protective barrier against free radicals play an important role in numerous metabolic and immunologic processes associated with oxidation-reduction reactions which take place during intracellular digestion of phagocyted bacteria. The aim of our study was to examine the properties of an organic compound of selenium, 4-(o-tolilo)-selenosemicarbazide of p-chlorobenzoic acid in terms of its retention in organs, effect on erythropoesis and phagocytic abilities of neutrophiles as well as antioxidant properties in neutrophiles tested with NBT test. This compound as well as inorganic sodium selenate was given to Swiss mice at the dose of 10(-3) g Se/kg for the period of 10 days. The concentrations of selenium in livers of mice treated with sodium selenate and selenosemicarbazide were found to be higher than in controls (18.7 micrograms lg-1 and 23.2 micrograms lg-1 vs. 12 micrograms lg-1, respectively). Analysis of blood cells count has shown a significant decrease in neutrophile levels in both groups treated with selenium. The influence of selenium compounds on phagocytosis and especially NBT test has been determined (3.8% of positive cells in the controls vs. 2.2% and 0.9% in the groups treated with sodium selenate and selenosemicarbazide, respectively). Our preliminary investigations suggest that selenosemicarbazides are biologically active compounds and can modify neutrophile functions. PMID:10816738

  19. SPECIATE 4.3: Addendum to SPECIATE 4.2--Speciation database development documentation

    EPA Science Inventory

    SPECIATE is the U.S. Environmental Protection Agency's (EPA) repository of volatile organic gas and particulate matter (PM) speciation profiles of air pollution sources. Among the many uses of speciation data, these source profiles are used to: (1) create speciated emissions inve...

  20. Selenium in the environment, metabolism and involvement in body functions.

    PubMed

    Mehdi, Youcef; Hornick, Jean-Luc; Istasse, Louis; Dufrasne, Isabelle

    2013-01-01

    Selenium (Se³⁴₇₉) is a metalloid which is close to sulfur (S) in terms of properties. The Se concentration in soil varies with type, texture and organic matter content of the soil and with rainfall. Its assimilation by plants is influenced by the physico-chemical properties of the soil (redox status, pH and microbial activity). The presence of Se in the atmosphere is linked to natural and anthropogenic activities. Selenoproteins, in which selenium is present as selenocysteine, present an important role in many body functions, such as antioxidant defense and the formation of thyroid hormones. Some selenoprotein metabolites play a role in cancer prevention. In the immune system, selenium stimulates antibody formation and activity of helper T cells, cytotoxic T cells and Natural Killer (NK) cells. The mechanisms of intestinal absorption of selenium differ depending on the chemical form of the element. Selenium is mainly absorbed in the duodenum and caecum by active transport through a sodium pump. The recommended daily intake of selenium varies from 60 μg/day for women, to 70 μg/day for men. In growing ruminants the requirements are estimated at 100 μg/kg dry matter and 200 μg/Kg for pregnant or lactating females. A deficiency can cause reproductive disorders in humans and animals. PMID:23486107

  1. Selenium reduces the proapoptotic signaling associated to NF-kappaB pathway and stimulates glutathione peroxidase activity during excitotoxic damage produced by quinolinate in rat corpus striatum.

    PubMed

    Santamaría, Abel; Vázquez-Román, Beatriz; La Cruz, Verónica Pérez-De; González-Cortés, Carolina; Trejo-Solís, Ma Cristina; Galván-Arzate, Sonia; Jara-Prado, Aurelio; Guevara-Fonseca, Jorge; Ali, Syed F

    2005-12-15

    Quinolinate (QUIN) neurotoxicity has been attributed to degenerative events in nerve tissue produced by sustained activation of N-methyl-D-aspartate receptor (NMDAr) and oxidative stress. We have recently described the protective effects that selenium (Se), an antioxidant, produces on different markers of QUIN-induced neurotoxicity (Santamaría et al., 2003, J Neurochem 86:479-488.). However, the mechanisms by which Se exerts its protective actions remain unclear. Since some of these events are thought to be related with inhibition of deadly molecular cascades through the activation of antioxidant selenoproteins, in this study we investigated the effects of Se on QUIN-induced cell damage elicited by the nuclear factor kappaB (NF-kappaB) pathway, as well as the time-course response of striatal glutathione peroxidase (GPx) activity. Se (sodium selenite, 0.625 mg/kg/day, i.p.) was administered to rats for 5 days, and 120 min after the last administration, animals received a single striatal injection of QUIN (240 nmol/mul). Twenty-four hours later, their striata were tested for the expression of IkappaB-alpha (the NF-kappaB cytosolic binding protein), the immunohistochemical expression of NF-kappaB (evidenced as nuclear expression of P65), caspase-3-like activation, and DNA fragmentation. Additional groups were killed at 2, 6, and 24 h for measurement of GPx activity. Se reduced the QUIN-induced decrease in IkappaB-alpha expression, evidencing a reduction in its cytosolic degradation. Se also prevented the QUIN-induced increase in P65-immunoreactive cells, suggesting a reduction of NF-kappaB nuclear translocation. Caspase-3-like activation and DNA fragmentation produced by QUIN were also inhibited by Se. Striatal GPx activity was stimulated by Se at 2 and 6 h, but not at 24 h postlesion. Altogether, these data suggest that the protective effects exerted by Se on QUIN-induced neurotoxicity are partially mediated by the inhibition of proapoptotic events underlying Ikappa

  2. 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. PMID:25908504

  3. Selenium incorporation using recombinant techniques

    SciTech Connect

    Walden, Helen

    2010-04-01

    An overview of techniques for recombinant incorporation of selenium and subsequent purification and crystallization of the resulting labelled protein. Using selenomethionine to phase macromolecular structures is common practice in structure determination, along with the use of selenocysteine. Selenium is consequently the most commonly used heavy atom for MAD. In addition to the well established recombinant techniques for the incorporation of selenium in prokaryal expression systems, there have been recent advances in selenium labelling in eukaryal expression, which will be discussed. Tips and things to consider for the purification and crystallization of seleno-labelled proteins are also included.

  4. Selenium for preventing cancer

    PubMed Central

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

    2015-01-01

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

  5. What Is Speciation?

    PubMed

    Shapiro, B Jesse; Leducq, Jean-Baptiste; Mallet, James

    2016-03-01

    Concepts and definitions of species have been debated by generations of biologists and remain controversial. Microbes pose a particular challenge because of their genetic diversity, asexual reproduction, and often promiscuous horizontal gene transfer (HGT). However, microbes also present an opportunity to study and understand speciation because of their rapid evolution, both in nature and in the lab, and small, easily sequenced genomes. Here, we review how microbial population genomics has enabled us to catch speciation "in the act" and how the results have challenged and enriched our concepts of species, with implications for all domains of life. We describe how recombination (including HGT and introgression) has shaped the genomes of nascent microbial, animal, and plant species and argue for a prominent role of natural selection in initiating and maintaining speciation. We ask how universal is the process of speciation across the tree of life, and what lessons can be drawn from microbes? Comparative genomics showing the extent of HGT in natural populations certainly jeopardizes the relevance of vertical descent (i.e., the species tree) in speciation. Nevertheless, we conclude that species do indeed exist as clusters of genetic and ecological similarity and that speciation is driven primarily by natural selection, regardless of the balance between horizontal and vertical descent. PMID:27030977

  6. What Is Speciation?

    PubMed Central

    Shapiro, B. Jesse; Leducq, Jean-Baptiste; Mallet, James

    2016-01-01

    Concepts and definitions of species have been debated by generations of biologists and remain controversial. Microbes pose a particular challenge because of their genetic diversity, asexual reproduction, and often promiscuous horizontal gene transfer (HGT). However, microbes also present an opportunity to study and understand speciation because of their rapid evolution, both in nature and in the lab, and small, easily sequenced genomes. Here, we review how microbial population genomics has enabled us to catch speciation “in the act” and how the results have challenged and enriched our concepts of species, with implications for all domains of life. We describe how recombination (including HGT and introgression) has shaped the genomes of nascent microbial, animal, and plant species and argue for a prominent role of natural selection in initiating and maintaining speciation. We ask how universal is the process of speciation across the tree of life, and what lessons can be drawn from microbes? Comparative genomics showing the extent of HGT in natural populations certainly jeopardizes the relevance of vertical descent (i.e., the species tree) in speciation. Nevertheless, we conclude that species do indeed exist as clusters of genetic and ecological similarity and that speciation is driven primarily by natural selection, regardless of the balance between horizontal and vertical descent. PMID:27030977

  7. Assessment of selenium pollution in agricultural soils in the Xuzhou District, Northwest Jiangsu, China.

    PubMed

    Huang, Shunsheng; Hua, Ming; Feng, Jinshun; Zhong, Xinyong; Jin, Yang; Zhu, Baiwan; Lu, Hua

    2009-01-01

    Xuzhou City is an important base for coal production and coal-fired power. To evaluate selenium contamination in this area, we sampled agricultural soil, soil profile, irrigation water, bedrock, coal, fly ash, paddy rice, and vegetables from the north of Xuzhou City, and determined their selenium contents. The background level of selenium in the soil profile was 0.08 mg/kg. The selenium concentrations in agricultural soils and irrigation water were in the range of 0.21-4.08 mg/kg and 0.002-0.29 mg/L, respectively. Soils with high selenium content were located closely to coalmines and power plants. The average selenium concentrations in coal and coal fly ash were 5.46 and 2.81 mg/kg, respectively. In contrast, the concentrations of selenium in bedrock and in the soil profile were very low. These results imply that the high selenium level in agricultural soils is mainly caused by anthropogenic activities, rather than by parent material. The arithmetic mean of selenium concentration in paddy rice was 0.116 mg/kg, and in cabbage was 0.05 mg/kg. The selenium concentration in rice was positively correlated with total selenium concentration in soil, suggesting that selenium in soil is readily transferred into the crops. Furthermore, the estimated dietary intake (88.8 microg) of selenium from paddy rice and cabbage exceeds the recommended dietary allowance (55 microg). Therefore, there is a potential health risk from consumption of local staple food in the study area. PMID:19634423

  8. Geochemical anomalies of toxic elements and arsenic speciation in airborne particles from Cu mining and smelting activities: influence on air quality.

    PubMed

    Sánchez de la Campa, Ana M; Sánchez-Rodas, Daniel; González Castanedo, Yolanda; de la Rosa, Jesús D

    2015-06-30

    A characterization of chemical composition and source contribution of PM10 in three representative environments of southwest Spain related to mining activities (mineral extraction, mining waste and Cu-smelting) has been performed. A study of geochemical anomalies was conducted in the samples collected at the three stations between July 2012 and October 2013. The influence of Cu-smelting processes was compared to other mining activities, where common tracers were identified. The Cu and As concentrations in the study area are higher than in other rural and urban stations of Spain, in which geochemical anomalies of As, Se, Bi, Cd, and Pb have been reported. The results of source contribution showed similar geochemical signatures in the industrial and mining factors. However, the contribution to PM10 is different according to the type of industrial activity. These results have been confirmed performing an arsenic speciation analysis of the PM10 samples, in which the mean extraction efficiency of arsenic depended on the origin of the samples. These finding indicate that the atmospheric particulate matter emitted from Cu-smelting has a high residence time in the atmosphere. This indicates that the Cu-smelter can impact areas of high ecological interest and considered as clean air. PMID:25748998

  9. Influence of the hydration by the environmental humidity on the metallic speciation and the photocatalytic activity of Cr/MCM-41

    SciTech Connect

    Elías, Verónica R.; Sabre, Ema V.; Winkler, Elin L.; Andrini, Leandro; Requejo, Félix G.; Casuscelli, Sandra G.; Eimer, Griselda A.

    2014-05-01

    The influence of the environmental humidity on the Cr species deposited on inorganic supports like MCM-41 silicates was analyzed by UV–vis Diffuse Reflectance (UV–vis RD), Electronic Spin Resonance (ESR) and X-ray near-edge (XANES) spectroscopy. Metal speciation could be inferred, finding that prolonged exposure periods under environmental humidity provoked the reduction of the active Cr{sup 6+} species and thus, the decrease of the Cr/MCM-41 photoactivity. After the Ti loading over the Cr modified samples, Cr species and the photoactivity were not notably influenced by the humidity exposure. Thus, it could be concluded that the presence of Ti is important because the TiO{sub 2} cover protects the oxidized Cr species, stabilizing them. - Graphical abstract: The load of Ti on the Cr modified MCM-41 produces a TiO{sub 2} cover that protects the active Cr species from their reduction by the environmental humidity. - Highlights: • Spectroscopic analysis shows presence of Cr{sup 6+}/Cr{sup 5+} in calcined/re-calcined samples. • Cr{sup 3+} species increase for hydrated samples causing their photoactivity decrease. • Samples with high Cr loadings are more sensitive to environmental humidity presence. • TiO{sub 2} cover protects oxidized Cr species from their reduction by the water. • Ti is important to allow a synergistic effect and to stabilize active Cr{sup 6+}/Cr{sup 5+}.

  10. Selenium compounds activate ATM-dependent DNA damage responses via the mismatch repair protein hMLH1 in colorectal cancer cells

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Epidemiological and animal studies indicate that selenium supplementation suppresses risk of colorectal and other cancers. The majority of colorectal cancers are characterized by a defective DNA mismatch repair (MMR) process. Here, we have employed the MMR-deficient HCT 116 colorectal cancer cells ...

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

    SciTech Connect

    Suzuki, Kazuo T. . E-mail: ktsuzuki@p.chiba-u.ac.jp; 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 its 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.

  12. Sorption and diffusion of selenium oxyanions in granitic rock.

    PubMed

    Ikonen, Jussi; Voutilainen, Mikko; Söderlund, Mervi; Jokelainen, Lalli; Siitari-Kauppi, Marja; Martin, Andrew

    2016-09-01

    atmosphere. The speciation of selenium was studied by HPLC-ICP-MS in simulated ground waters of each of the rock types. The Kd of selenium was found to be in the range of (6.2-7.0±2.0)×10(-3)m(3)/kg in crushed rock whereas the Kd obtained from block scale through diffusion experiment varied between (1.5±0.3)×10(-3)m(3)/kg and (1.0±0.6)×10(-4)m(3)/kg. The De of selenium was significantly higher for GG; De=(2.5±1.5)×10(-12)m(2)/s than for KGG; De=(7±2)×10(-13)m(2)/s due to the higher permeability of GG compared with KGG. PMID:27517514

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

    PubMed

    Yan, Lin; Johnson, LuAnn K

    2011-06-01

    This study determined the bioavailability of selenium (Se) from yellow peas and oats harvested from the high-Se soil of South Dakota, United States. The Se concentrations were 13.5 ± 0.2 and 2.5 ± 0.1 mg/kg (dry weight) for peas and oats, respectively. Male weanling Sprague-Dawley rats were depleted of Se by feeding them a 30% Torula yeast-based diet (4.1 μg Se/kg) for 56 days, and then they were replenished with Se for an additional 50 days by feeding them the same diet supplemented with 20, 30, or 40 μg Se/kg from peas or oats, respectively. Selenium bioavailability was determined on the basis of the restoration of Se-dependent enzyme activities and tissue Se concentrations in Se-depleted rats, comparing those responses for yellow peas and oats to those for l-selenomethionine (SeMet; used as a reference) by using a slope-ratio method. Dietary supplementation with peas or oats resulted in linear or log-linear, dose-dependent increases in glutathione peroxidase activities in blood and liver and in thioredoxin reductase activity in liver. Supplementation with peas or oats resulted in linear or log-linear, dose-dependent increases in Se concentrations of plasma, liver, gastrocnemius muscle, and kidneys. The overall bioavailability was approximately 88% for Se from yellow peas and 92% from oats, compared to SeMet. It was concluded that Se from naturally produced high-Se yellow peas or oats is highly bioavailable in this model and that these high-Se foods may be a good dietary source of Se. PMID:21553810

  14. Selenium accumulation in lettuce germplasm

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Selenium (Se) is an essential micronutrient for animals and humans. Increasing Se content in food crops offers an effective approach to reduce the widespread selenium deficiency problem in many parts of the world. In this study, we evaluated thirty diverse accessions of lettuce (Lactuca sativa L.) f...

  15. Genome differentiation in a species pair of coregonine fishes: an extremely rapid speciation driven by stress-activated retrotransposons mediating extensive ribosomal DNA multiplications

    PubMed Central

    2013-01-01

    in both genomes, thus, leading to a rapid genome divergence. We attribute these extensive genome re-arrangements associated with speciation event to stress-induced retrotransposons (re)activation. Such causal interplay between genome differentiation, retrotransposons (re)activation and environmental conditions may become a topic to be explored in a broader genomic context in future evolutionary studies. PMID:23410024

  16. Selenium Uptake and Volatilization by Marine Algae

    NASA Astrophysics Data System (ADS)

    Luxem, Katja E.; Vriens, Bas; Wagner, Bettina; Behra, Renata; Winkel, Lenny H. E.

    2015-04-01

    Selenium (Se) is an essential trace nutrient for humans. An estimated one half to one billion people worldwide suffer from Se deficiency, which is due to low concentrations and bioavailability of Se in soils where crops are grown. It has been hypothesized that more than half of the atmospheric Se deposition to soils is derived from the marine system, where microorganisms methylate and volatilize Se. Based on model results from the late 1980s, the atmospheric flux of these biogenic volatile Se compounds is around 9 Gt/year, with two thirds coming from the marine biosphere. Algae, fungi, and bacteria are known to methylate Se. Although algal Se uptake, metabolism, and methylation influence the speciation and bioavailability of Se in the oceans, these processes have not been quantified under environmentally relevant conditions and are likely to differ among organisms. Therefore, we are investigating the uptake and methylation of the two main inorganic Se species (selenate and selenite) by three globally relevant microalgae: Phaeocystis globosa, the coccolithophorid Emiliania huxleyi, and the diatom Thalassiosira oceanica. Selenium uptake and methylation were quantified in a batch experiment, where parallel gas-tight microcosms in a climate chamber were coupled to a gas-trapping system. For E. huxleyi, selenite uptake was strongly dependent on aqueous phosphate concentrations, which agrees with prior evidence that selenite uptake by phosphate transporters is a significant Se source for marine algae. Selenate uptake was much lower than selenite uptake. The most important volatile Se compounds produced were dimethyl selenide, dimethyl diselenide, and dimethyl selenyl sulfide. Production rates of volatile Se species were larger with increasing intracellular Se concentration and in the decline phase of the alga. Similar experiments are being carried out with P. globosa and T. oceanica. Our results indicate that marine algae are important for the global cycling of Se

  17. Selenium suppresses leukemia through the action of endogenous eicosanoids.

    PubMed

    Gandhi, Ujjawal H; Kaushal, Naveen; Hegde, Shailaja; Finch, Emily R; Kudva, Avinash K; Kennett, Mary J; Jordan, Craig T; Paulson, Robert F; Prabhu, K Sandeep

    2014-07-15

    Eradicating cancer stem-like cells (CSC) may be essential to fully eradicate cancer. Metabolic changes in CSC could hold a key to their targeting. Here, we report that the dietary micronutrient selenium can trigger apoptosis of CSC derived from chronic or acute myelogenous leukemias when administered at supraphysiologic but nontoxic doses. In leukemia CSC, selenium treatment activated ATM-p53-dependent apoptosis accompanied by increased intracellular levels of reactive oxygen species. Importantly, the same treatment did not trigger apoptosis in hematopoietic stem cells. Serial transplantation studies with BCR-ABL-expressing CSC revealed that the selenium status in mice was a key determinant of CSC survival. Selenium action relied upon the endogenous production of the cyclooxygenase-derived prostaglandins Δ(12)-PGJ2 and 15d-PGJ2. Accordingly, nonsteroidal anti-inflammatory drugs and NADPH oxidase inhibitors abrogated the ability of selenium to trigger apoptosis in leukemia CSC. Our results reveal how selenium-dependent modulation of arachidonic acid metabolism can be directed to trigger apoptosis of primary human and murine CSC in leukemia. PMID:24872387

  18. 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).

  19. Selenium elimination in pigs after an outbreak of selenium toxicosis.

    PubMed

    Davidson-York, D; Galey, F D; Blanchard, P; Gardner, I A

    1999-07-01

    In May 1996, 150 grower pigs in 5 California counties were exposed to selenium-contaminated feed distributed by a single feed company. Feed samples from 20 herds had a mean selenium concentration of 121.7 ppm dry weight (range, 22.1-531 ppm). In San Luis Obispo County, 52 pigs in 24 herds were exposed to the feed, and 8 pigs died with signs of paralysis. Bilateral symmetrical poliomyelomalacia involving the ventral horns of the cervical and lumbar intumescence was evident on histologic examination of spinal cord from affected pigs. Of 44 surviving exposed pigs, 33 (75%) exhibited signs of selenosis, including anorexia, alopecia, and hoof lesions. Thirty-nine of 44 pigs (88.6%) had elevated (>1 ppm) blood selenium concentrations. Surviving exposed pigs were changed to a standard commercial ration containing approximately 0.5 ppm (dry weight) selenium. Blood selenium concentrations were determined weekly for 46 days following removal of the contaminated feed and were compared with values of 20 control pigs fed a standard commercial ration. Mean (+/-SD) blood selenium concentrations of exposed pigs were 3.2 +/- 2.6 ppm at the initial sampling and 0.4 +/- 0.1 ppm after 46 days. Mean blood selenium concentrations of < or = 0.3 ppm for control pigs at all samplings were significantly lower (P < 0.001) than concentrations for exposed pigs. Muscle and liver samples of 22 of the 44 exposed pigs were collected at slaughter approximately 72 days after withdrawal of the selenium-contaminated feed. Muscle samples had a mean selenium concentration of 0.36 ppm (wet weight). Liver samples had a mean selenium concentration of 1.26 ppm (wet weight). One liver sample had a selenium value in the toxic range for pigs (3.3 ppm wet weight; reference range, 0.4-1.2 ppm). A 1-compartment pharmacokinetic model of selenium elimination in exposed pigs was generated, and the geometric mean blood selenium elimination half-life was estimated to be 12 days. The 60-day withdrawal time recommended

  20. [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

  1. Low selenium status in the elderly influences thyroid hormones.

    PubMed

    Olivieri, O; Girelli, D; Azzini, M; Stanzial, A M; Russo, C; Ferroni, M; Corrocher, R

    1995-12-01

    1. Iodothyronine 5'-deiodinase, which is mainly responsible for peripheral triiodothyronine (T3) production, has recently been demonstrated to be a selenium-containing enzyme. In the elderly, reduced peripheral conversion of thyroxine (T4) to T3 and overt hypothyroidism are frequently observed. 2. We measured serum selenium and erythrocyte glutathione peroxidase (as indices of selenium status), thyroid hormones and thyroid-stimulating hormone in 109 healthy euthyroid subjects (52 women, 57 men), carefully selected to exclude abnormally low thyroid hormone levels induced by acute or chronic diseases or calorie restriction. The subjects were subdivided into three age groups. To avoid conditions of under-nutrition or malnutrition, dietary records were obtained for a sample of 24 subjects, randomly selected and representative of the whole population for age and sex. 3. In order to properly assess the influence of selenium status on iodothyronine 5'-deiodinase type I activity, a double-blind placebo-controlled trial was also carried out on 36 elderly subjects, resident at a privately owned nursing home. 4. In the free-living population, a progressive reduction of the T3/T4 ratio (due to increased T4 levels) and of selenium and erythrocyte glutathione peroxidase activity was observed with advancing age. A highly significant linear correlation between T4, T3/T4 and selenium was observed in the population as a whole (for T4, R = -0.312, P < 0.002; for T3/T4 ratio, R = 0.32, P < 0.01) and in older subjects (for T4, R = -0.40, P < 0.05; for T3/T4 ratio, R = 0.54, P < 0.002). 5. The main result of the double-blind placebo-controlled trial was a significant improvement of selenium indices and a decrease in the T4 level in selenium-treated subjects; serum selenium, erythrocyte glutathione peroxidase activity and thyroid hormones did not change in placebo-treated subjects. 6. We concluded that selenium status influences thyroid hormones in the elderly, mainly modulating T4

  2. Occurrence of selenium in sulfides from some sedimentary rocks of the western United States

    USGS Publications Warehouse

    Coleman, Robert G.; Delevaux, Maryse

    1956-01-01

    Investigations of the minor- and trace-element content of sulfides associated with uranium ore deposits from sandstone-type deposits have shown that selenium commonly substitutes for sulfur. The Morrison formation and Entrada sandstone of Jurassic age and the Wind River formation of Eocene age seem to be seleniferous stratigraphic zones; sulfides deposited within these formations generally contain abnormal amounts of selenium. The selenium content of the pyrite, marcasite, and chalcocite is much greater than that reported in previously published data. Under the prevailing temperatures and pressures of formation of the Colorado Plateau uranium deposits the maximum amount of Se substituting for S in the pyrite structure was found to be 3 percent by weight. Ferroselite, the iron selenide (FeSe2), was found in two deposits on the Colorado Plateau and it was also established that galena (PbS) forms an isomorphous series with clausthalite (PbSe) in nature. During oxidation of the selenium-bearing sulfides and selenides in the Colorado Plateau and Wyoming, the selenium forms pinkish crusts of either monoclinic or hexagonal native selenium intergrown with soluble sulfates, suggesting that under "normal" oxidizing conditions native selenium is more stable than selenites or selenates. The above-normal selenium content of these sulfides from sedimentary rocks of Mesozoic and Tertiary age is significant. The high selenium in these sulfides is related to periods of volcanic and intrusive activity penecontemporaneous with the formation of the containing sediments.

  3. 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

  4. Pinto beans as a course of bioavailable selenium to support bone structure in mice

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Selenium (Se) is an essential trace mineral for animals and humans. The deficiency of Se has been linked to increased oxidative stress with increased levels of reactive oxygen species (ROS). Oxidative stress and ROS have been shown to stimulate bone resorption and osteoclast activity. Selenium, a ch...

  5. Anti-tumor and immunomodulatory activity of selenium (Se)-polysaccharide from Se-enriched Grifola frondosa.

    PubMed

    Mao, Guang-Hua; Ren, Yi; Li, Qian; Wu, Hui-Yu; Jin, Dun; Zhao, Ting; Xu, Cai-Quan; Zhang, Deng-Hong; Jia, Qing-Dong; Bai, Yan-Peng; Yang, Liu-Qing; Wu, Xiang-Yang

    2016-01-01

    A polysaccharide termed Se-GP11 was extracted and purified from Se-enriched Grifola frondosa in our previous study. This study investigated the characterization, anti-tumor and immunomodulatory activity of Se-GP11. The results showed that Se-GP11 was composed of mannose, glucose and galactose with a molar ratio of 1:4.91:2.41. The weight-average molecular weight (Mw) and weight-average mean square radius (Rw) of Se-GP11 in 0.1M sodium chloride solution were 3.3×10(4)Da and 32.8 nm. Se-GP11 existed as a globular conformation with random coil structure. Se-GP11 had no anti-tumor activity against HepG-2 cells in vitro, and it significantly inhibited the growth of Heps tumor in vivo. Se-GP11 increased the relatively thymus and spleen weights as well as serum necrosis factor-alpha (TNF-α) and interleukin-2 (IL-2) levels. In addition, Se-GP11 promoted the phagocytosis and NO production of RAW264.7 as compared with that of the normal control group. The results revealed that the Se-GP11 may exhibit the anti-tumor through improving immunologic function of the tumor bearing mice. PMID:26522247

  6. The two faces of selenium-deficiency and toxicity--are similar in animals and man.

    PubMed Central

    Koller, L D; Exon, J H

    1986-01-01

    The purpose of this review article is to demonstrate the close parallelism of daily requirements, biological activity and minimum and maximum tolerable levels of selenium for animals and man. In addition, the carcinogenic/anticarcinogenic properties of selenium are discussed and a postulate of how these dichotomous effects may occur in accordance with selenium-induced immunomodulation is presented. A review of pertinent literature pertaining to the biological action of selenium in animals and man, including deficiency, toxicity, carcinogenicity and effects on immunity, is included to support these concepts. The predominant biochemical action of selenium in both animals and man is to serve as an antioxidant via the selenium-dependent enzyme, glutathione peroxidase, and thus protect cellular membranes and organelles from peroxidative damage. The signs and symptoms of selenium deficiency closely simulate each other for animals and man. Severe deficiency is characterized by cardiomyopathy while moderate deficiency results in less severe, myodegenerative syndromes such as muscular weakness and pain as well as a variety of other selenium-associated diseases. Clinical manifestations of many of these disorders require contributory factors, such as stress, to precipitate symptoms which are documented for animals and implicated for humans. Current evidence suggests that a daily selenium consumption for man of approximately 30 micrograms is necessary to prevent the selenium-deficient syndrome, Keshan disease, while approximately 90 micrograms/day/adult should be the minimum daily requirement for optimum biological performance. Recognizing that humans in several countries do not meet the proposed minimum daily requirement of 90 micrograms, several compelling reasons are presented in deriving this minimal daily nutritional intake. Selenosis can occur in laboratory animals, livestock, and humans following long-term exposure to selenium concentrations as low as 5 mg selenium

  7. 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. PMID:25847169

  8. Biosensor for metal analysis and speciation

    DOEpatents

    Aiken, Abigail M.; Peyton, Brent M.; Apel, William A.; Petersen, James N.

    2007-01-30

    A biosensor for metal analysis and speciation is disclosed. The biosensor comprises an electron carrier immobilized to a surface of an electrode and a layer of an immobilized enzyme adjacent to the electrode. The immobilized enzyme comprises an enzyme having biological activity inhibited by a metal to be detected by the biosensor.

  9. 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

  10. ORGANIC SPECIATION SAMPLING ARTIFACTS

    EPA Science Inventory

    Sampling artifacts for molecular markers from organic speciation of particulate matter were investigated by analyzing forty-one samples collected in Philadelphia as a part of the Northeast Oxidant and Particulate Study (NEOPS). Samples were collected using a high volume sampler ...

  11. Cerebrospinal fluid of newly diagnosed amyotrophic lateral sclerosis patients exhibits abnormal levels of selenium species including elevated selenite

    PubMed Central

    Vinceti, Marco; Solovyev, Nikolay; Mandrioli, Jessica; Crespi, Catherine M.; Bonvicini, Francesca; Arcolin, Elisa; Georgoulopoulou, Eleni; Michalke, Bernhard

    2013-01-01

    Exposure to selenium, and particularly to its inorganic forms, has been hypothesized as a risk factor for amyotrophic lateral sclerosis (ALS), a fast progressing motor neuron disease with poorly understood etiology. However, no information is known about levels of inorganic and some organic selenium species in the central nervous system of ALS patients, and recent observations suggest that peripheral biomarkers of exposure are unable to predict these levels for several Se species including the inorganic forms. Using a hospital-referred cases-control series and advanced selenium speciation methods, we compared the chemical species of selenium in cerebrospinal fluid from thirty-eight ALS patients to those of thirty-eight reference neurological patients matched on age and gender. We found that higher concentrations of inorganic selenium in the form of selenite and of human serum albumin-bound selenium were associated with increased ALS risk (relative risks 3.9 (95% confidence interval 1.2–11.0) and 1.7 (1.0–2.9) for 0.1µg/l increase). Conversely, lower concentrations of selenoprotein P-bound selenium were associated with increased risk (relative risk 0.2 for 1µg/l increase, 95% confidence interval 0.04–0.8). The associations were stronger among cases age 50 years or older, who are postulated to have lower rates of genetic disease origin. These results suggest that excess selenite and human serum albumin bound-selenium and low levels of selenoprotein P-bound selenium in the central nervous system, which may be related, may play a role in ALS etiology. PMID:23732511

  12. Seed Priming with Selenium: Consequences for Emergence, Seedling Growth, and Biochemical Attributes of Rice.

    PubMed

    Khaliq, Abdul; Aslam, Farhena; Matloob, Amar; Hussain, Saddam; Geng, Mingjian; Wahid, Abdul; ur Rehman, Hafeez

    2015-08-01

    The present study was undertaken to appraise the role of selenium priming for improving emergence and seedling growth of basmati rice. Seeds of two fine rice cultivars (Super and Shaheen Basmati) were primed with concentrations of 15, 30, 45, 60, 75, 90, and 105 μmol L(-1) selenium. Untreated dry- and hydro-primed seeds were maintained as the control and positive control, respectively. Selenium priming resulted in early commencement of emergence, triggered seedling growth irrespective of rice cultivar over untreated control, and was more effective than hydro-priming except at higher concentrations. Lower electrical conductivity of seed leachates, reduced lipid peroxidation, greater α-amylase activity, higher soluble sugars, and enhanced activities of enzymatic antioxidants (superoxide dismutase (SOD), peroxidase (POX), catalase (CAT), and glutathione peroxidase (GPX)) were observed in seeds primed with selenium. Rice seedlings derived from selenium-primed seeds exhibited more chlorophyll contents, while total phenolics were comparable with those of the control seedlings. The improved starch metabolism, greater membrane stability, and increased activity of antioxidants were considered as possible mechanisms responsible for such improvements in emergence and seedling vigor of rice mediated by selenium priming. Priming with selenium (15-60 μmol L(-1)) favored rice emergence and seedling growth. Nevertheless, soaking seeds in relatively concentrated (90 and 105 μmol L(-1)) selenium solution had overall detrimental effects. PMID:25690516

  13. Synthesis of selenium-containing Artemisia sphaerocephala polysaccharides: Solution conformation and anti-tumor activities in vitro.

    PubMed

    Wang, Junlong; Li, Qingyao; Bao, Aijuan; Liu, Xiurong; Zeng, Junyuan; Yang, Xiaopin; Yao, Jian; Zhang, Ji; Lei, Ziqiang

    2016-11-01

    It has been reported in our previous work that selenized Artemisia sphaerocephala polysaccharides (SeASPs) with the Se content range of 168-1703μg/g were synthesized by using Na2SeO3/HNO3/BaCl2 system. In the present work, the solution property of SeASP was studied by using size exclusion chromatography combined with multi angle laser light scattering (SEC-MALLS). A decrease in df values indicated that SeASPs with different conformational features that were highly dependent on MW. SeASPs exhibited a more rigid conformation (df value of 1.29-1.52) in low molecular weight range (MW of 1.026-1.426×10(4)g/mol) and compact spherical conformation in high molecular weight range (MW of 2.268-4.363×10(4)g/mol). It could be due to the degradation of polysaccharide chains in HNO3, which was supported in monosaccharide composition analysis. Congo red (CR) spectrophotometric method and atomic force microscopy (AFM) results also confirmed the conformational transition and the evidence on the shape of the rigid chains. In vitro anti-tumor assays, SeASP2 displayed greater anti-proliferative effects against three tumor cell lines (hepatocellular carcinoma HepG-2 cells, lung adenocarcinom A549 cells and cervical squamous carcinoma Hela cells) in a dose-dependent manner. This suggested that selenylation could significantly enhance the anti-tumor activities of polysaccharide derivatives in vitro. PMID:27516251

  14. Selenium in biology: facts and medical perspectives.

    PubMed

    Köhrl, J; Brigelius-Flohé, R; Böck, A; Gärtner, R; Meyer, O; Flohé, L

    2000-01-01

    Several decades after the discovery of selenium as an essential trace element in vertebrates approximately 20 eukaryotic and more than 15 prokaryotic selenoproteins containing the 21st proteinogenic amino acid, selenocysteine, have been identified, partially characterized or cloned from several species. Many of these proteins are involved in redox reactions with selenocysteine acting as an essential component of the catalytic cycle. Enzyme activities have been assigned to the glutathione peroxidase family, to the thioredoxin reductases, which were recently identified as selenoproteins, to the iodothyronine deiodinases, which metabolize thyroid hormones, and to the selenophosphate synthetase 2, which is involved in selenoprotein biosynthesis. Prokaryotic selenoproteins catalyze redox reactions and formation of selenoethers in (stress-induced) metabolism and energy production of E. coli, of the clostridial cluster XI and of other prokaryotes. Apart from the specific and complex biosynthesis of selenocysteine, selenium also reversibly binds to proteins, is incorporated into selenomethionine in bacteria, yeast and higher plants, or posttranslationally modifies a catalytically essential cysteine residue of CO dehydrogenase. Expression of individual eukaryotic selenoproteins exhibits high tissue specificity, depends on selenium availability, in some cases is regulated by hormones, and if impaired contributes to several pathological conditions. Disturbance of selenoprotein expression or function is associated with deficiency syndromes (Keshan and Kashin-Beck disease), might contribute to tumorigenesis and atherosclerosis, is altered in several bacterial and viral infections, and leads to infertility in male rodents. PMID:11076017

  15. Population differentiation without speciation

    PubMed Central

    Magurran, A. E.

    1998-01-01

    Population differentiation is often viewed as an important step towards speciation, and part of the rationale for conserving variation at the intraspecific level is that the potential to generate more biological diversity should be retained. Yet, speciation is not an inevitable consequence of population divergence. This paper reviews recent work on the Trinidadian guppy, Poecilia reticulata, a species that is renowned for its capacity for population differentiation. Guppy populations evolve rapidly, within 101 to 102 generations, as a response to changes in selection exerted by predators. The rates of evolution involved can be up to seven orders of magnitude greater than those seen in the fossil record. Sexual selection, particuarly female choice, appears to reinforce the divergence that natural selection has generated. Perplexingly, however, there is no reproductive isolation (either prezygotic or postzygotic) between populations, even those that have been separated for at least 106 generations. Sexual conflict may be the key to explaining this absence of speciation. Male reproductive behaviour, particularly the high incidence of sneaky mating, may be instrumental in producing sufficient gene flow to prevent reproductive isolation. Sneaky mating has the potential to undermine female choice, and is known to be an important means of sperm transfer in wild populations. Sexual dimorphism, also a result of sexual conflict in guppies, may inhibit speciation in another way. Morphological differences between the sexes, that have arisen for reproductive reasons, mean that males and females are pre-adapted for different foraging niches. This, in turn, reduces the opportunity for the development of feeding polymorphisms, a mechanism that seems to have been important in the sympatric speciation of other fish species.

  16. Identification in human urine and blood of a novel selenium metabolite, Se-methylselenoneine, a potential biomarker of metabolization in mammals of the naturally occurring selenoneine, by HPLC coupled to electrospray hybrid linear ion trap-orbital ion trap MS.

    PubMed

    Klein, Marlène; Ouerdane, Laurent; Bueno, Maïté; Pannier, Florence

    2011-05-01

    Speciation analysis of selenium in human urine allowed for the first time the identification of a novel selenium metabolite, Se-methylselenoneine. Despite a concentration at low ppb level, its characterization was achieved after sample purification by solid phase extraction (SPE) followed by the parallel coupling of the bidimensional RP/HILIC chromatography with ICP-MS and ESI-LTQ Orbitrap MS detection. To confirm its biological significance with regards to selenoneine, the recently discovered analog of ergothioneine, and to discard the possibility of sample preparation artifacts, a new method was developed to monitor its actual presence, as well as the occurrence of its sulfur and/or non-methylated analogs, in non-preconcentrated urine and blood samples of non-supplemented humans. It consisted in a HILIC ESI-MS(3) method in high resolution mode (resolution 30 000 at m/z 400) with large isolation width windows for precursor ions. These two particular settings allowed respectively to keep observing the specific mass defect of selenium- and sulfur-containing molecules and to maintain the characteristic selenium pattern in product ions created through MS(n) fragmentations. As a result, all four metabolites were detected in blood and three of them in urine. Moreover, different ratios "methylated/non-methylated" were observed between urine and blood samples, which seemed to indicate their active metabolization. The analytical tool developed here will be of a great importance to further study the occurrence and the potential metabolic role in mammalian organelles, cells and fluids of these very particular and promising redox metabolites. PMID:21331438

  17. Impacts of chemical amendment and plant growth on lead speciation and enzyme activities in a shooting range soil: an x-ray absorption fine structure investigation.

    PubMed

    Hashimoto, Yohey; Matsufuru, Hiroki; Takaoka, Masaki; Tanida, Hajime; Sato, Takeshi

    2009-01-01

    In situ chemical immobilization is a practical remediation technology for metal-contaminated soils because of its capability to reduce cost and environmental impacts. We assessed the immobilization effects of poultry waste amendment and plant growth (Panicum maximum Jacq.) on Pb speciation and enzyme activities in shooting range soils. Soil contaminated with Pb was obtained from the top 20 cm of a shooting range. To evaluate Pb mobility in the soil profile treated with plants and immobilizing amendment, we used large columns filled with Pb-contaminated soil (0-20 cm, surface soils) and non-contaminated soil (20-75 cm, subsurface soils). The column study demonstrated that the amendment reduced the toxicity characteristic leaching procedure-extractable Pb in the surface soil by 90% of the Control soil. Lead mobility from the surface to subsurface profiles was significantly attenuated by plant growth but was promoted by the amendment without plant application. The extended X-ray absorption fine structure analysis revealed that the amendment reduced the proportion of PbCO(3) and Pb-organic complexes and transformed them into a more geochemically stable species of Pb(5)(PO(4))(3)Cl with 30 to 35% of the total Pb species. Applications of plant and amendment increased activities of dehydrogenase and phosphatase in the surface soil with 2.7- and 1.1-fold greater than those in Control, respectively. The use of amendments in combination with plant growth may have potential as an integrated remediation strategy that enables Pb immobilization and soil biological restoration in shooting range soils. PMID:19465717

  18. Selenium semiconductor core optical fibers

    SciTech Connect

    Tang, G. W.; Qian, Q. Peng, K. L.; Wen, X.; Zhou, G. X.; Sun, M.; Chen, X. D.; Yang, Z. M.

    2015-02-15

    Phosphate glass-clad optical fibers containing selenium (Se) semiconductor core were fabricated using a molten core method. The cores were found to be amorphous as evidenced by X-ray diffraction and corroborated by Micro-Raman spectrum. Elemental analysis across the core/clad interface suggests that there is some diffusion of about 3 wt % oxygen in the core region. Phosphate glass-clad crystalline selenium core optical fibers were obtained by a postdrawing annealing process. A two-cm-long crystalline selenium semiconductor core optical fibers, electrically contacted to external circuitry through the fiber end facets, exhibit a three times change in conductivity between dark and illuminated states. Such crystalline selenium semiconductor core optical fibers have promising utility in optical switch and photoconductivity of optical fiber array.

  19. Simple thermodynamic model of unassisted proton shuttle uncoupling and prediction of activity from calculated speciation, lipophilicity, and molecular geometry.

    PubMed

    Martineau, Louis C

    2012-06-21

    A mechanistic model of uncoupling of oxidative phosphorylation by lipophilic weak acids (i.e. proton shuttles) was developed for the purposes of predicting the relative activity of xenobiotics of widely varying structure and of guiding the design of optimized derivatives. The model is based on thermodynamic premises not formulated elsewhere that allow for the calculation of steady-state conditions and of rate of energy dissipation on the basis of acid-dissociation and permeability behavior, the later estimated from partitioning behavior and geometric considerations. Moreover, permeability of either the neutral or of the ionized species is proposed to be effectively enhanced under conditions of asymmetrical molecular distribution. Finally, special considerations were developed to accommodate multi-protic compounds. The comparison of predicted to measured activity for a diverse testset of 48 compounds of natural origin spanning a wide range of activity yielded a Spearman's rho of 0.90. The model was used to tentatively identify several novel proton shuttles, as well as to elucidate core structures particularly conducive to proton shuttle activity from which optimized derivatives can be designed. Principles of design were formulated and examples of derivatives projected to be active at concentrations on the order of 10(-7)M are proposed. Among these are di-protic compounds predicted to shuttle two protons per cycle iteration and proposed to maximally exploit the proton shuttle mechanism. This work promotes the design of highly active, yet easily-metabolized uncouplers for therapeutic applications, namely the indirect activation of AMP-kinase, as well as for various industrial applications where low persistence is desirable. PMID:22425608

  20. Selenium status in workers handling aromatic nitro-amino compounds in a chemical factory

    SciTech Connect

    Yoshida, M.; Sunaga, M.; Hara, I. )

    1990-09-01

    The selenium status of workers handling aromatic nitro-amino (ANA) compounds was evaluated by measurement of their blood and urinary selenium concentrations and blood glutathione peroxidase (GSH-Px) activities. Forty-seven healthy Japanese male workers (42.7 +/- 12.1 yr) handling ANA compounds routinely in a chemical factory were studied as exposed workers, and 107 nonindustrial healthy Japanese males (39.3 +/- 10.0 yr) in the same region served as a control group. Urinary diazoreaction-positive metabolites and methemoglobin, both of which have been used as indices of exposure to ANA compounds, were significantly elevated in the exposed workers. Both plasma and erythrocyte selenium in the exposed workers showed 20% lower values compared to the control group. GSH-Px activities in plasma and erythrocytes were also significantly decreased in the exposed workers, but urinary selenium excretions were similar between the two groups. Questionnaire information obtained from each subject regarding intake habits of selenium-rich foods (bread, eggs, meat, and fish) indicated that the average dietary selenium intake was similar for the control group and the exposed workers. These results indicate that (1) the workers handling ANA compounds were surely exposed to these chemicals; (2) their selenium status was lower than that of the nonindustrial controls; and (3) the low selenium status was not associated with any dietary factor.

  1. Genomics of homoploid hybrid speciation: diversity and transcriptional activity of long terminal repeat retrotransposons in hybrid sunflowers

    PubMed Central

    Renaut, Sebastien; Rowe, Heather C.; Ungerer, Mark C.; Rieseberg, Loren H.

    2014-01-01

    Hybridization is thought to play an important role in plant evolution by introducing novel genetic combinations and promoting genome restructuring. However, surprisingly little is known about the impact of hybridization on transposable element (TE) proliferation and the genomic response to TE activity. In this paper, we first review the mechanisms by which homoploid hybrid species may arise in nature. We then present hybrid sunflowers as a case study to examine transcriptional activity of long terminal repeat retrotransposons in the annual sunflowers Helianthus annuus, Helianthus petiolaris and their homoploid hybrid derivatives (H. paradoxus, H. anomalus and H. deserticola) using high-throughput transcriptome sequencing technologies (RNAseq). Sampling homoploid hybrid sunflower taxa revealed abundant variation in TE transcript accumulation. In addition, genetic diversity for several candidate genes hypothesized to regulate TE activity was characterized. Specifically, we highlight one candidate chromatin remodelling factor gene with a direct role in repressing TE activity in a hybrid species. This paper shows that TE amplification in hybrid lineages is more idiosyncratic than previously believed and provides a first step towards identifying the mechanisms responsible for regulating and repressing TE expansions. PMID:24958919

  2. A role for p53 in selenium-induced senescence

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The tumor suppressor p53 and the ataxia-telangiectasia mutated (ATM) kinase play important roles in the senescence response to oncogene activation and DNA damage. We have previously shown that selenium-containing compounds can activate an ATM-dependent senescence response in MRC-5 normal fibroblasts...

  3. Living organisms as an alternative to hyphenated techniques for metal speciation. Evaluation of baker's yeast immobilized on silica gel for Hg speciation*1

    NASA Astrophysics Data System (ADS)

    Pérez-Corona, Teresa; Madrid-Albarrán, Yolanda; Cámara, Carmen; Beceiro, Elisa

    1998-02-01

    The use of living organisms for metal preconcentration and speciation is discussed. Among substrates, Saccharomyces cerevisiae baker's yeast has been successfully used for the speciation of mercury [Hg(II) and CH 3Hg +], selenium [Se(IV) and Se(VI)] and antimony [Sb(III) and Sb(V)]. To illustrate the capabilities of these organisms, the analytical performance of baker's yeast immobilized on silica gel for on-line preconcentration and speciation of Hg(II) and methylmercury is reported. The immobilized cells were packed in a PTFE microcolumn, through which mixtures of organic and inorganic mercury solutions were passed. Retention of inorganic and organic mercury solutions took place simultaneously, with the former retained in the silica and the latter on the yeast. The efficiency uptake for both species was higher than 95% over a wide pH range. The speciation was carried out by selective and sequential elution with 0.02 mol L -1 HCl for methylmercury and 0.8 mol L -1 CN - for Hg(II). This method allows both preconcentration and speciation of mercury. The preconcentration factors were around 15 and 100 for methylmercury and mercury(II), respectively. The method has been successfully applied to spiked sea water samples.

  4. A simple sonochemical approach for synthesis of selenium nanostructures and investigation of its light harvesting application.

    PubMed

    Panahi-Kalamuei, Mokhtar; Mousavi-Kamazani, Mehdi; Salavati-Niasari, Masoud; Hosseinpour-Mashkani, S Mostafa

    2015-03-01

    Selenium (Se) nanostructures were synthesized by a sonochemical method using SeCl₄ as a new precursor for Se nanostructures. Moreover, hydrazine, potassium borohydride, and thioglycolic acid were used as reducing reagents in aqueous solution. Ultrasonic power, irradiation time, reducing agent, solvent, HCl, NaOH, and the surfactant were changed in order to investigate the effect of preparation parameters on the morphology and particle size of selenium. The obtained Se with different morphologies and sizes was characterized by XRD, SEM, TEM, EDS, and DRS. The selenium nanostructures exhibited enhanced photocatalytic activity in the degradation of methylene blue (MB) under visible light irradiation. Furthermore, to examine the solar cell application of as-synthesized selenium nanostructure, FTO/TiO₂/Se/Pt-FTO and FTO/Se/CdS/Pt-FTO structures were created by deposited selenium film on top of the TiO₂ layer and FTO glass prepared by Doctor's blade method, respectively. PMID:25248917

  5. Effects of selenium and light wavelengths on liquid culture of Cordyceps militaris Link.

    PubMed

    Dong, J Z; Liu, M R; Lei, C; Zheng, X J; Wang, Y

    2012-04-01

    To investigate the effects of selenium and light wavelengths on the growth of liquid-cultured Cordyceps militaris and the main active components' accumulation, culture conditions as selenium selenite concentrations and light of different wavelengths were studied. The results are: adenosine accumulation proved to be significantly selenium dependent (R(2) = 0.9403) and cordycepin contents were determined to be not significantly selenium dependent (R(2) = 0.3845) but significantly enhanced by selenium except for 20 ppm; there were significant differences in cordycepin contents, adenosine contents, and mycelium growth caused by light wavelengths: cordycepin, blue light > pink light > daylight, darkness, red light; adenosine, red light > pink light, darkness, daylight, blue light; and mycelium growth, red light > pink light, darkness, daylight > blue light. In conclusion, light wavelength had a significant influence on production of mycelia, adenosine, and cordycepin, so lightening wavelength should be changed according to target products in the liquid culture of C. militaris. PMID:22434354

  6. Redox activity and chemical speciation of size fractioned PM in the communities of the Los Angeles-Long Beach harbor

    NASA Astrophysics Data System (ADS)

    Hu, S.; Polidori, A.; Arhami, M.; Shafer, M. M.; Schauer, J. J.; Cho, A.; Sioutas, C.

    2008-11-01

    In this study, two different types of assays were used to quantitatively measure the redox activity of PM and to examine its intrinsic toxicity: 1) in vitro exposure to rat alveolar macrophage (AM) cells using dichlorofluorescin diacetate (DCFH-DA) as the fluorescent probe (macrophage ROS assay), and: 2) consumption of dithiothreitol (DTT) in a cell-free system (DTT assay). Coarse (PM10-2.5), accumulation (PM2.5-0.25), and quasi-ultrafine (quasi-UF, PM0.25) mode particles were collected weekly at five sampling sites in the Los Angeles-Long Beach harbor and at one site near the University of Southern California campus (urban site). All PM samples were analyzed for organic (total and water-soluble) and elemental carbon, organic species, inorganic ions, and total and water-soluble elements. Quasi-UF mode particles showed the highest redox activity at all Long Beach sites (on both a per-mass and per-air volume basis). A significant association (R2=0.61) was observed between the two assays, indicating that macrophage ROS and DTT levels are affected at least partially by similar PM species. Relatively small variation was observed for the DTT measurements across all size fractions and sites, whereas macrophage ROS levels showed more significant ranges across the three different particle size modes and throughout the sites (coefficients of variation, or CVs, were 0.35, 0.24 and 0.53 for quasi-UF, accumulation, and coarse mode particles, respectively). Association between the PM constituents and the redox activity was further investigated using multiple linear regression models. The results showed that OC was the most important component influencing the DTT activity of PM samples. The variability of macrophage ROS was explained by changes in OC concentrations and water-soluble vanadium (probably originating from ship emissions bunker oil combustion). The multiple regression models were used to predict the average diurnal DTT levels as a function of the OC concentration at

  7. Redox activity and chemical speciation of size fractioned PM in the communities of the Los Angeles - Long Beach Harbor

    NASA Astrophysics Data System (ADS)

    Hu, S.; Polidori, A.; Arhami, M.; Shafer, M. M.; Schauer, J. J.; Cho, A.; Sioutas, C.

    2008-06-01

    In this study, two different types of assays were used to quantitatively measure the redox activity of PM and to examine its intrinsic toxicity: 1) in vitro exposure to rat alveolar macrophage (AM) cells using dichlorofluorescin diacetate (DCFH-DA) as the fluorescent probe (macrophage ROS assay), and: 2) consumption of dithiothreitol (DTT) in a cell-free system (DTT assay). Coarse (PM10-2.5), accumulation (PM2.5-0.25), and quasi-ultrafine (quasi-UF, PM0.25) mode particles were collected weekly at five sampling sites in the Los Angeles-Long Beach Harbor and at one site near the University of Southern California campus (urban site). All PM samples were analyzed for organic (total and water-soluble) and elemental carbon, organic species, inorganic ions, and total and water-soluble elements. Quasi-UF mode particles showed the highest redox activity at all Long Beach sites (on both a per-mass and per-air volume basis). A significant association (R2=0.61) was observed between the two assays, indicating that macrophage ROS and DTT levels are affected at least partially by similar PM species. Relatively small variation was observed for the DTT measurements across all size fractions and sites, whereas macrophage ROS levels showed more significant ranges across the three different particle size modes and throughout the sites (coefficients of variation, or CVs, were 0.35, 0.24 and 0.53 for quasi-UF, accumulation, and coarse mode particles, respectively). Association between the PM constituents and the redox activity was further investigated using multiple linear regression models. The results showed that OC was the most important component influencing the DTT activity of PM samples. The variability of macrophage ROS was explained by changes in OC concentrations and water-soluble vanadium (probably originating from ship emissions - bunker oil combustion). The multiple regression models were used to predict the average diurnal macrophage ROS and DTT levels as a function of the

  8. The effect of pH and natural microbial phosphatase activity on the speciation of uranium in subsurface soils

    NASA Astrophysics Data System (ADS)

    Beazley, Melanie J.; Martinez, Robert J.; Webb, Samuel M.; Sobecky, Patricia A.; Taillefert, Martial

    2011-10-01

    The biomineralization of U(VI) phosphate as a result of microbial phosphatase activity is a promising new bioremediation approach to immobilize uranium in both aerobic and anaerobic conditions. In contrast to reduced uranium minerals such as uraninite, uranium phosphate precipitates are not susceptible to changes in oxidation conditions and may represent a long-term sink for uranium in contaminated environments. So far, the biomineralization of U(VI) phosphate has been demonstrated with pure cultures only. In this study, two uranium contaminated soils from the Department of Energy Oak Ridge Field Research Center (ORFRC) were amended with glycerol phosphate as model organophosphate source in small flow-through columns under aerobic conditions to determine whether natural phosphatase activity of indigenous soil bacteria was able to promote the precipitation of uranium(VI) at pH 5.5 and 7.0. High concentrations of phosphate (1-3 mM) were detected in the effluent of these columns at both pH compared to control columns amended with U(VI) only, suggesting that phosphatase-liberating microorganisms were readily stimulated by the organophosphate substrate. Net phosphate production rates were higher in the low pH soil (0.73 ± 0.17 mM d -1) compared to the circumneutral pH soil (0.43 ± 0.31 mM d -1), suggesting that non-specific acid phosphatase activity was expressed constitutively in these soils. A sequential solid-phase extraction scheme and X-ray absorption spectroscopy measurements were combined to demonstrate that U(VI) was primarily precipitated as uranyl phosphate minerals at low pH, whereas it was mainly adsorbed to iron oxides and partially precipitated as uranyl phosphate at circumneutral pH. These findings suggest that, in the presence of organophosphates, microbial phosphatase activity can contribute to uranium immobilization in both low and circumneutral pH soils through the formation of stable uranyl phosphate minerals.

  9. The Association between Hantavirus Infection and Selenium Deficiency in Mainland China

    PubMed Central

    Fang, Li-Qun; Goeijenbier, Marco; Zuo, Shu-Qing; Wang, Li-Ping; Liang, Song; Klein, Sabra L.; Li, Xin-Lou; Liu, Kun; Liang, Lu; Gong, Peng; Glass, Gregory E.; van Gorp, Eric; Richardus, Jan H.; Ma, Jia-Qi; Cao, Wu-Chun; de Vlas, Sake J.

    2015-01-01

    Hemorrhagic fever with renal syndrome (HFRS) caused by hantaviruses and transmitted by rodents is a significant public health problem in China, and occurs more frequently in selenium-deficient regions. To study the role of selenium concentration in HFRS incidence we used a multidisciplinary approach combining ecological analysis with preliminary experimental data. The incidence of HFRS in humans was about six times higher in severe selenium-deficient and double in moderate deficient areas compared to non-deficient areas. This association became statistically stronger after correction for other significant environment-related factors (low elevation, few grasslands, or an abundance of forests) and was independent of geographical scale by separate analyses for different climate regions. A case-control study of HFRS patients admitted to the hospital revealed increased activity and plasma levels of selenium binding proteins while selenium supplementation in vitro decreased viral replication in an endothelial cell model after infection with a low multiplicity of infection (MOI). Viral replication with a higher MOI was not affected by selenium supplementation. Our findings indicate that selenium deficiency may contribute to an increased prevalence of hantavirus infections in both humans and rodents. Future studies are needed to further examine the exact mechanism behind this observation before selenium supplementation in deficient areas could be implemented for HFRS prevention. PMID:25609306

  10. Isolation and characterization of a selenium metabolism mutant of Salmonella typhimurium

    SciTech Connect

    Kramer, G.F.; Ames, B.N.

    1988-02-01

    Selenium is a constituent in Escherichia coli of the anaerobic enzyme formate dehydrogenase in the form of selenocysteine. Selenium is also present in the tRNA of E. coli in the modified base 5-methylaminomethyl-2-selenouracil (mnm/sup 5/Se/sup 2/U). The pathways of bacterial selenium metabolism are largely uncharacterized, and it is unclear whether nonspecific reactions in the sulfur metabolic pathways may be involved. We demonstrated that sulfur metabolic pathway mutants retain a wild-type pattern of selenium incorporation, indicating that selenite (SeO/sub 3//sup 2 -/) is metabolized entirely via selenium-specific pathways. To investigate the function of mnm/sup 5/Se/sup 2/U, we isolated a mutant which is unable to incorporate selenium into tRNA. This strain was obtained by isolating mutants lacking formate dehydrogenase activity and then screening for the inability to metabolize selenium. This phenotype is the result of a recessive mutation which appears to map in the general region of 21 min on the Salmonella typhimurium chromosome. We showed that the absence of selenium incorporation into suppressor tRNA reduces the efficiency of suppression of nonsense codons in certain contexts and when wobble base pairing is required. Thus, one function of mnm/sup 5/Se/sup 2/U in tRNA may be in codon-anticodon interactions.

  11. Importance of selenium and selenoprotein for brain function: From antioxidant protection to neuronal signalling.

    PubMed

    Solovyev, Nikolay D

    2015-12-01

    Multiple biological functions of selenium manifest themselves mainly via 25 selenoproteins that have selenocysteine at their active centre. Selenium is vital for the brain and seems to participate in the pathology of disorders such as Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis and epilepsy. Since selenium was shown to be involved in diverse functions of the central nervous system, such as motor performance, coordination, memory and cognition, a possible role of selenium and selenoproteins in brain signalling pathways may be assumed. The aim of the present review is to analyse possible relations between selenium and neurotransmission. Selenoproteins seem to be of special importance in the development and functioning of GABAergic (GABA, γ-aminobutyric acid) parvalbumin positive interneurons of the cerebral cortex and hippocampus. Dopamine pathway might be also selenium dependent as selenium shows neuroprotection in the nigrostriatal pathway and also exerts toxicity towards dopaminergic neurons under higher concentrations. Recent findings also point to acetylcholine neurotransmission involvement. The role of selenium and selenoproteins in neurotransmission might not only be limited to their antioxidant properties but also to inflammation, influencing protein phosphorylation and ion channels, alteration of calcium homeostasis and brain cholesterol metabolism. Moreover, a direct signalling function was proposed for selenoprotein P through interaction with post-synaptic apoliprotein E receptors 2 (ApoER2). PMID:26398431

  12. The evolutionary genetics of speciation.

    PubMed Central

    Coyne, J A; Orr, H A

    1998-01-01

    The last decade has brought renewed interest in the genetics of speciation, yielding a number of new models and empirical results. Defining speciation as 'the origin of reproductive isolation between two taxa', we review recent theoretical studies and relevant data, emphasizing the regular patterns seen among genetic analyses. Finally, we point out some important and tractable questions about speciation that have been neglected. PMID:9533126

  13. Production of selenium-72 and arsenic-72

    DOEpatents

    Phillips, Dennis R.

    1993-01-01

    Methods for producing selenium-72, separating it from its daughter isotope arsenic-72, and generating multiple portions of a solution containing arsenic-72 from a reusable parent substance comprised of selenium-72.

  14. Production of selenium-72 and arsenic-72

    DOEpatents

    Phillips, D.R.

    1993-04-20

    Methods are described for producing selenium-72, separating it from its daughter isotope arsenic-72, and generating multiple portions of a solution containing arsenic-72 from a reusable parent substance comprised of selenium-72.

  15. Characterization of Technetium Speciation in Cast Stone

    SciTech Connect

    Um, Wooyong; Jung, Hun Bok; Wang, Guohui; Westsik, Joseph H.; Peterson, Reid A.

    2013-11-11

    This report describes the results from laboratory tests performed at Pacific Northwest National Laboratory (PNNL) for the U.S. Department of Energy (DOE) EM-31 Support Program (EMSP) subtask, “Production and Long-Term Performance of Low Temperature Waste Forms” to provide additional information on technetium (Tc) speciation characterization in the Cast Stone waste form. To support the use of Cast Stone as an alternative to vitrification for solidifying low-activity waste (LAW) and as the current baseline waste form for secondary waste streams at the Hanford Site, additional understanding of Tc speciation in Cast Stone is needed to predict the long-term Tc leachability from Cast Stone and to meet the regulatory disposal-facility performance requirements for the Integrated Disposal Facility (IDF). Characterizations of the Tc speciation within the Cast Stone after leaching under various conditions provide insights into how the Tc is retained and released. The data generated by the laboratory tests described in this report provide both empirical and more scientific information to increase our understanding of Tc speciation in Cast Stone and its release mechanism under relevant leaching processes for the purpose of filling data gaps and to support the long-term risk and performance assessments of Cast Stone in the IDF at the Hanford Site.

  16. Heavy metal speciation in the composting process.

    PubMed

    Greenway, Gillian M; Song, Qi Jun

    2002-04-01

    Composting is one of the more efficient and environment friendly methods of solid waste disposal and has many advantages when compared with landfill disposal on which the UK and Ireland are currently heavily dependent. Composting is a very complicated process involving intensive microbial activity and the detailed mechanisms of the process have yet to be fully understood. Metal speciation information can provide an insight into the metal-microbial interaction and would help in the evaluation of the quality of compost. This would facilitate the exploitation of composts in remediation of heavy metal contaminated land. In this work a systematic approach to metal speciation in compost has been taken by applying the three-step method for operationally defined metal speciation of soils and sediments, developed by the European Commission's Standards, Measurement and Testing Programme to monitor the change in metal speciation with time (up to 106 days) for four different waste composting processes. The results have shown that in general metals become less available for the first extraction step as the composting process proceeds. This implies that composting tends to redistribute the metals from more labile forms to more fixed forms which may explain why the application of composts could be useful for with heavy metal contaminated land. There are exceptions to this trend and in some cases, certain metals appear to behave differently depending on the source of the compost. PMID:11993774

  17. Arsenic Speciation in Groundwater: Role of Thioanions

    EPA Science Inventory

    The behavior of arsenic in groundwater environments is fundamentally linked to its speciation. Understanding arsenic speciation is important because chemical speciation impacts reactivity, bioavailability, toxicity, and transport and fate processes. In aerobic environments arsen...

  18. Involvement of neuroleptic drugs in selenium deficiency and sudden death of cardiac origin: study and human post-mortem examination.

    PubMed

    Hamdan, Lamia; Bost, Muriel; Chazot, Guy; Bui-Xuan, Bernard; Vaillant, Fanny; Dehina, Leila; Descotes, Jacques; Tabib, Alain; Mamou, Zahida; Timour, Quadiri

    2012-06-01

    The involvement of psychotropic drugs in sudden deaths has been highlighted. The objective of this work was to establish a link between selenium levels in heart tissue, psychotropic treatment and sudden death. Selenium levels were measured by electrothermal atomic absorption spectroscopy post-mortem in heart, brain and liver. Histological examination evidenced dilated cardiomyopathy in 45% of cases, left ventricular hypertrophy in 36%, and ischemic coronaropathy in 18%. A significant reduction of myocardial selenium levels compared to controls was seen in patients treated with neuroleptic drugs or meprobamate. No changes in brain or liver selenium levels were seen. These results suggest that selenium deficiency can facilitate sudden death in patients on psychotropic drugs. The reduced activity of glutathione peroxidase due to selenium deficiency can result in augmented oxidative stress in myocardial cells and myocardiopathy leading to sudden death. PMID:22664334

  19. The antimicrobial effects of selenium nanoparticle-enriched probiotics and their fermented broth against Candida albicans

    PubMed Central

    2014-01-01

    Background Lactic acid bacteria are considered important probiotics for prevention of some infections. The aim of this work was to investigate the effect of selenium dioxide on the antifungal activity of Lactobacillus plantarum and L. johnsonii against Candida albicans. Methods Lactobacillus plantarum and L. johnsonii cells, grown in the presence and absence of selenium dioxide, and their cell-free spent culture media were tested for antifungal activity against C. albicans ATCC 14053 by a hole-plate diffusion method and a time-kill assay. Results Both L. plantarum and L. johnsonii reduced selenium dioxide to cell-associated elemental selenium nanoparticles. The cell-free spent culture media, from both Lactobacillus species that had been grown with selenium dioxide for 48 h, showed enhanced antifungal activity against C. albicans. Enhanced antifungal activity of cell biomass against C. albicans was also observed in cultures grown with selenium dioxide. Conclusions Selenium dioxide-treated Lactobacillus spp. or their cell-free spent broth inhibited the growth of C. albicans and should be investigated for possible use in anti-Candida probiotic formulations in future. PMID:24906455

  20. Sources and cycling of selenium in the western and equatorial Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Cutter, Gregory A.; Cutter, Lynda S.

    The concentration and chemical speciation of selenium were determined at six vertical profile stations along a 11,000-km-long horizontal transect from 34°S to 8°N in the western Atlantic. The depth profiles of total dissolved selenium, selenite (SeIV), and selenate (VI) all showed surface-water depletion and deep-water enrichment characteristic of the nutrient-like behavior of selenium that has been observed in other ocean basins. In North Atlantic Deep Water, the Se(IV)/Se(VI) ratios were generally similar to those found in the eastern Atlantic and North Pacific (0.7), but waters originating in the higher latitudes of the southern hemisphere, Antarctic Intermediate (AAIW) and Bottom Water, and Upper Circumpolar Deep Water (UCDW), were enriched in selenate and had correspondingly low Se(IV)/Se(VI) ratios (ca. 0.4). In contrast to these inorganic selenium species, organic selenide had maxima in the surface waters of the oligotrophic stations and undetectable concentrations in the mid- and deep waters. One exception to this pattern was found at the southernmost station (33°S) where a secondary organic selenide maximum was found in the AAIW and UCDW (700-1900 m). This observation can be explained by considering the 10-year residence time of organic selenide in the water column and the relatively young age (<3 yr) of these subducted surface waters. In the surface transect, total dissolved selenium showed only minor variations with oceanic regime (0.55-0.83 nM) except in the offshore plume of the Amazon River, where concentrations dropped as low as 0.19 nM. Organic selenide was the predominant form of dissolved selenium in surface waters (50±11%), followed by selenate (36±13%) and then selenite (14±6%). Cross-flow ultra filtration experiments indicated that surface water dissolved organic selenide is in a<1-kD fraction and thus truly dissolved. Selenate had higher concentrations in the southern hemisphere (0.24 nM) than in the north (0.17 nM), but the highest

  1. Analytical and mineralogical study of a Ghana manganese ore: Quantification of Mn speciation and effect of mechanical activation.

    PubMed

    He, Hongping; Cao, Jianglin; Duan, Ning

    2016-11-01

    In-depth understanding of the manganese ore would be beneficial to make the best use more environmental-friendly. A Ghana manganese ore before/after mechanical activation (MA) was therefore extensively characterized in our investigation. Surface Mn(4+)(35.5%), Mn(3+)(35.9%), Mn(2+)(28.6%) were detected by XPS, though XRD only revealed the presence of Mn(2+)-containing minerals. Thermal decomposition curve of manganese ore obtained by TG-DSC was divided into four stages from 373.15 K to 1273.15 K, which were quite consistent with the pattern of generated gases obtained by TG-FTIR and the theoretical thermodynamics analysis of the incorporated components involving ΔGT(θ) and Kp(θ). Mn species distribution showed no difference for manganese ores before/after MA, but quantitative analysis showed the decrease of residual Mn content (cannot be extracted effectively by acid, from about 12% to 1%), and thereby the increased contents of other four Mn species (exchangeables, carbonates, oxides, organics), which was suggested to be correlated with the dissociation of Mn-containing flocs and SiO2 particles witnessed by SEM-EDS. It was also found that MA could obviously promote the Mn dissolution kinetics in acid condition, though the dissolution of manganese ore before/after MA were both diffusion controlled. This investigation gives benignant inspiration for the resource utilization of manganese ore, taking the increasingly severer situation of Mn resource supply into consideration. PMID:27474911

  2. Mercury and selenium interaction: A review

    SciTech Connect

    Cuvin-Aralar, M.L.; Furness, R.W. )

    1991-06-01

    This paper reviews studies on mercury and selenium interaction. It includes the effects of selenium on mercury toxicity on the organism, organ/tissue, and subcellular levels. The paper also touches on possible mechanisms for the protective action of selenium against mercury toxicity and deals briefly with the synergism between the two elements. 71 references.

  3. 21 CFR 573.920 - Selenium.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

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

  4. 21 CFR 573.920 - Selenium.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

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

  5. Selenium in the environment and human health

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Although selenium was shown to affect biological systems over 80 years ago and was recognized as an essential micronutrient in the mid-20th century, the "flowering" of the selenium field has taken place in the 21st century. The biological function of selenium through selenoproteins has been firmly e...

  6. SPECIATE--EPA'S DATABASE OF SPECIATED EMISSION PROFILES

    EPA Science Inventory

    SPECIATE is EPA's repository of Total Organic Compound and Particulate Matter speciated profiles for a wide variety of sources. The profiles in this system are provided for air quality dispersion modeling and as a library for source-receptor and source apportionment type models. ...

  7. PM2.5 speciation -- objectives, requirements, and approach

    SciTech Connect

    Homolya, J.B.; Rice, J.; Scheffe, R.D.

    1998-12-31

    Chemical speciation of selected PM2.5 monitor samples is included in the discussion of major monitoring requirements and principles described in the Part 58 Rule. The regulation requires the implementation of a modest chemical speciation network of 50 PM2.5 sites that provides a first order characterization of the metals, ions, and carbon constituents of PM2.5. These data are to be used to support several areas of interest, including: (1) Helping to implement the PM2.5 standard through the use of speciated data as inputs to air quality modeling analyses and as indicators to track progress of controls; (2) Aiding the interpretation of health studies by linking effects to PM2.5 constituents; (3) Understanding the effects of atmospheric constituents on visibility impairment; and (4) Using speciated particulate data to aid in monitoring network design and siting adjustment. For these reasons, EPA has developed plans for the initial 50-site speciation monitoring network that include collocating at least 25 monitors within the Photochemical Air Monitoring System (PAMS) which collect data for a range of volatile hazardous air pollutants and ozone. Therefore these initial speciation sites will provide EPA and the research community a baseline of gaseous and particulate atmospheric characterization information. Current plans include the outfitting of up to 300 PM2.5 speciation monitoring sites. The speciation monitors are currently being fabricated under EPA National Federal Reference Method monitor procurement contracts and are projected to begin to be deployed in 10/98. This paper will present a detailed discussion of the design and implementation of the speciation monitoring network and explain EPA`s approach to implementation of the monitoring activities which includes siting, target analytes of interest, sample handling, analytical SOPs, and data reduction, validation and reporting.

  8. Selenium supplementation induces metalloproteinase-dependent L-selectin shedding from monocytes.

    PubMed

    Ahrens, Ingo; Ellwanger, Christoph; Smith, Belinda K; Bassler, Nicole; Chen, Yung Chih; Neudorfer, Irene; Ludwig, Andreas; Bode, Christoph; Peter, Karlheinz

    2008-06-01

    Selenium therapy in patients with severe sepsis improves clinical outcome and has been associated with increased activity of the selenoprotein glutathione peroxidase. However, the mechanism of the observed beneficial effects remains unclear. We determined the effect of selenium treatment on the monocyte adhesion molecule L-selectin and L-selectin-related monocyte functions in vitro and transferred our findings to an in vivo mouse model. Monocytes were purified, cultured, and incubated in the presence or absence of supplemented selenium and metalloproteinase (MP) inhibitors for up to 16 h. Expression of L-selectin was unaffected after 2 and 6 h but decreased after 16 h of incubation in the presence of selenium. Soluble L-selectin (sL-selectin) in the supernatant was determined by ELISA. A 2.3-fold increase as a result of shedding of L-selectin was observed after 16 h of selenium treatment. Addition of the MP inhibitors GM6001, TNF-alpha-converting enzyme inhibitor 2, or GW280264X strongly reduced selenium-induced L-selectin shedding, indicating a MP-dependent mechanism. The functional consequences of L-selectin shedding were examined in a flow chamber model. Selenium-treated monocytes showed significantly decreased rolling and adhesion to the L-selectin ligand Sialyl-Lewis(a) under conditions of venous shear stress (0.5 dyne/cm(2)). Selenium treatment of C57BL6 mice led to increased serum levels of sL-selectin, underscoring the in vivo relevance of our findings. We describe a selenium-induced down-regulation of L-selectin on monocytes as a consequence of MP-dependent shedding of this membrane-anchored adhesion molecule. The impairment of monocyte adhesion by selenium supplementation may represent an important, underlying mechanism for the modulation of inflammatory reactions in patients with severe sepsis. PMID:18305178

  9. Selenium reverses Pteridium aquilinum-induced immunotoxic effects

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We have previously shown that bracken fern (Pteridium aquilinum) has immunomodulatory effects on mouse natural killer (NK) cells by reducing cytotoxicity. Alternatively, it has been demonstrated that selenium can enhance NK cell activity. Therefore, the aims of the present study were to evaluate if ...

  10. Determination of selenium in the environment and in biological material.

    PubMed Central

    Bem, E M

    1981-01-01

    This paper reviews the following problems, sampling, decomposition procedures and most important analytical methods used for selenium determination, e.g., neutron activation analysis, atomic absorption spectrometry, gas-liquid chromatography, spectrophotometry, fluorimetry, and x-ray fluorescence. This review covers the literature mainly from 1975 to 1977. PMID:7007035

  11. Global advances in selenium research from theory to application

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Selenium is without question one of the most influential natural-occurring trace elements for biological systems worldwide. The multi-faceted connections between the environment, food crops, human and animal health and selenium’s function through selenoprotein activity, have been well characterized....

  12. Hydrological and geochemical investigations of selenium behavior at Kesterson Reservoir

    SciTech Connect

    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 soluble 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.

  13. Preparation, homogeneity and stability studies of a candidate LRM for Se speciation.

    PubMed

    Bodó, Erzsébet Tünde; Stefánka, Zsolt; Ipolyi, Ildikó; Sörös, Csilla; Dernovics, Mihály; Fodor, Péter

    2003-09-01

    A laboratory reference material (LRM) was prepared from Brazil nuts (Bertholletia excelsa) for quality control (QC) purposes of selenium speciation. The preparation of this LRM led through the usual operation steps applied during routine reference material production from biota samples-preparation of the raw material, homogenisation, storage design, checking of homogeneity, microbiological status and possible irradiation effects, and monitoring the species stability vs time at different storage temperatures. The selenium speciation studies to check species stability were carried out on a HPLC-UV-HG-AFS measurement set-up. Special attention was paid to the correct identification of selenium species by applying independent HPLC separation techniques (ion-pairing and anion-exchange chromatography). The concentration of selenomethionine (SeMet) and total Se content were quantified (79.9 microg g(-1) (calculated as Se) and 82.9 microg g(-1), respectively). The homogeneity and stability of this candidate reference material passed the relevant tests recommended by Bureau Communautaire de Référence (BCR). PMID:12750870

  14. The drivers of tropical speciation.

    PubMed

    Smith, Brian Tilston; McCormack, John E; Cuervo, Andrés M; Hickerson, Michael J; Aleixo, Alexandre; Cadena, Carlos Daniel; Pérez-Emán, Jorge; Burney, Curtis W; Xie, Xiaoou; Harvey, Michael G; Faircloth, Brant C; Glenn, Travis C; Derryberry, Elizabeth P; Prejean, Jesse; Fields, Samantha; Brumfield, Robb T

    2014-11-20

    Since the recognition that allopatric speciation can be induced by large-scale reconfigurations of the landscape that isolate formerly continuous populations, such as the separation of continents by plate tectonics, the uplift of mountains or the formation of large rivers, landscape change has been viewed as a primary driver of biological diversification. This process is referred to in biogeography as vicariance. In the most species-rich region of the world, the Neotropics, the sundering of populations associated with the Andean uplift is ascribed this principal role in speciation. An alternative model posits that rather than being directly linked to landscape change, allopatric speciation is initiated to a greater extent by dispersal events, with the principal drivers of speciation being organism-specific abilities to persist and disperse in the landscape. Landscape change is not a necessity for speciation in this model. Here we show that spatial and temporal patterns of genetic differentiation in Neotropical birds are highly discordant across lineages and are not reconcilable with a model linking speciation solely to landscape change. Instead, the strongest predictors of speciation are the amount of time a lineage has persisted in the landscape and the ability of birds to move through the landscape matrix. These results, augmented by the observation that most species-level diversity originated after episodes of major Andean uplift in the Neogene period, suggest that dispersal and differentiation on a matrix previously shaped by large-scale landscape events was a major driver of avian speciation in lowland Neotropical rainforests. PMID:25209666

  15. Characterization of selenium species in Brazil nuts by HPLC-ICP-MS and ES-MS.

    PubMed

    Vonderheide, Anne P; Wrobel, Kazimierz; Kannamkumarath, Sasi S; B'Hymer, Clayton; Montes-Bayón, Maria; Ponce De León, Claudia; Caruso, Joseph A

    2002-09-25

    Brazil nuts have been classified as the foodstuffs that contain the highest level of unadulterated selenium, an essential trace element that appears to prevent cancer. To date, characterization of the selenium species in brazil nuts has not yet been investigated. In this work, various sample preparation approaches, including microwave extractions and enzymatic treatments, are examined with the goal of species preservation and subsequent selenium speciation; of these approaches, an enzymatic treatment with Proteinase K proved most effective. High-performance liquid chromatography (HPLC) separation strategies and inductively coupled plasma mass spectrometry (ICP-MS) detection schemes will also be presented. Extracts are evaluated against available standards for the commercially obtainable seleno-amino acids, selenomethionine (SeMet), selenoethionine (SeEt), and selenocystine (SeCys); selenomethionine was demonstrated to be the most abundant of these seleno-amino acids. Further characterization of unidentified selenium-containing peaks is attempted by the employment of several procedures, including electrospray-mass spectrometry (ES-MS). A peptide structure was identified; however, this was considered a tentative proposal due to the large background produced by the extremely complicated brazil nut matrix. PMID:12236705

  16. [Selenium status in population of Irkutsk region].

    PubMed

    Golubkina, N A; Parfenova, E O; Reshetnik, L A

    1998-01-01

    The human selenium status in 10 locations of Irkutsk region (n = 216) is estimated using serum and hair selenium as biological markers. Extremely low serum selenium was typical for the inhabitants of Angara area (63-84 mcg/l). Hair selenium varied from 504 mcg/kg to 718 mcg/kg, the lowest values being found in Shelehov and Angarsk, the highest--in Karam and Mama. Low selenium concentrations were found also in the main food products: cereals--49-89 mcg/kg, meat--234-489 mcg/kg of dry weight, bread--106-180 mcg/kg of dry weight. PMID:9825469

  17. JV Task - 116 Selenium's Role in the Seafood Safety Issue

    SciTech Connect

    Nicholas Ralston; Laura Raymond

    2009-03-30

    Continuing studies under these three funded projects - (JV Task 77 The Health Implications of the Mercury-Selenium Interaction, JV Task 96 Investigating the Importance of the Mercury-Selenium Interaction, and JV Task 116 Selenium's Role in the Seafood Safety Issue) - were performed to determine the effects of different levels of dietary mercury and selenium on the growth and development of test animals, and related tissue analyses, to understand the protective benefits of dietary selenium in reference to low-level exposure to mercury. Maternal exposure to methylmercury from seafood has been found to cause neurodevelopmental harm in children. However, significant nutritional benefits will be lost if fish consumption is needlessly avoided. The results of these studies support the hypothesis that intracellular Se itself is the physiologically important biomolecule and that the harm of mercury toxicity arises when Hg abundance becomes great enough to bind a significant portion of intracellular Se in vulnerable tissues such as the brain. Formation of HgSe limits bioavailability of Se for synthesis of Se-dependent enzymes, particularly in brain tissues. When production of these enzymes is impaired, the loss of their numerous essential functions results in the signs and symptoms of Hg toxicity. The finding that one mole of Se protects against many moles of Hg indicates that its beneficial effect is not due to sequestration of mercury as HgSe but rather due to the biological activity of the Se. Therefore, the selenium content of seafoods must be considered along with their methylmercury contents in evaluating the effect of dietary exposure to mercury.

  18. Selenium accumulation in mammals exposed to contaminated California irrigation drainwater

    USGS Publications Warehouse

    Clark, D.R., Jr.

    1987-01-01

    In May 1984, 332 mammals of 10 species were collected at Kesterson Reservoir (San Joaquin Valley, Merced Co., CA), which had received selenium-laden irrigation drainwater, and at the nearby Volta Wildlife Area, which had not. The study concentrated on the California vole (Microtus californicus); 88 were taken at Kesterson, 89 at Volta. Mean selenium concentrations in livers were as much as 522 times higher at Kesterson. There were species-to-species differences at Kesterson; higher selenium concentrations occurred in carnivorous species and/or species that feed on foods closely linked to pond water. There were also pond-to-pond differences at Kesterson; drainwater historically was delivered to Ponds 1 and 2, where concentrations in 1984 were higher, with subsequent flow to other ponds, where they were lower. Whereas none of 50 adult female voles from Kesterson was pregnant, 12 of 41 (29%) from Volta were pregnant. However, this cessation of reproductive activity at Kesterson was probably not due to selenium toxicity but could have resulted because drying conditions at Kesterson forced voles to a seed diet earlier than at Volta. One malformation was found among five embryonic litters of three species from Kesterson. Mammals seem much less susceptible to selenium-induced embryonic abnormalities than birds. No adverse impacts of selenium on wild mammals were demonstrated; however, some sensitive species might have been extirpated from Kesterson before this study began. In addition, high concentrations in small mammal species at Kesterson may threaten predatory birds and mammals that feed on them, with the endangered San Joaquin kit fox (Vulpes macrotis mutica) of particular concern.

  19. 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.

  20. 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. PMID:23535542

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

    SciTech Connect

    Hasunuma, Ryoichi; Tsuda, Morizo; Ogawa, Tadao; Kawanishi, Yasuhiro

    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 methodology 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.

  2. The extraction of different proteins in selenium enriched peanuts and their antioxidant properties.

    PubMed

    Zhao, P; Wang, Y; Zhang, Y; Guo, T; Zhang, Z; Zhang, W J; Zhang, X G; Ashraf, Muhammad Aqeel

    2016-05-01

    In this study, the selenium enriched peanuts and the different solubility proteins extracted from them were investigated. The dried defatted selenium enriched peanuts (SeP) powder (0.3147 μg/g) had a 2.5-fold higher mean total selenium concentration than general peanuts (GP) power (0.1233 μg/g). The SeP had higher concentration of selenium, manganese and zinc than that of GP, but less calcium. The rate of extraction of protein was 23.39% for peanuts and alkali soluble protein was the main component of protein in SeP, which accounted for 92.82% of total soluble protein and combined selenium was 77.33% of total selenium protein. In different forms of proteins from SeP, the WSePr due to higher concentration of selenium had higher DPPH free-radical scavenging activity, higher reducing activity and longer induction time than other proteins. PMID:27081360

  3. Selenium Content in Seafood in Japan

    PubMed Central

    Yamashita, Yumiko; Yamashita, Michiaki; Iida, Haruka

    2013-01-01

    Selenium is an essential micronutrient for humans, and seafood is one of the major selenium sources, as well as red meat, grains, eggs, chicken, liver and garlic. A substantial proportion of the total amount of selenium is present as selenium containing imidazole compound, selenoneine, in the muscles of ocean fish. In order to characterize the selenium content in seafood, the total selenium levels were measured in the edible portions of commercially important fish and shellfish species. Among the tested edible portions, alfonsino muscle had the highest selenium levels (concentration of 1.27 mg/kg tissue). High levels of selenium (1.20–1.07 mg/kg) were also found in the salted ovary products of mullet and Pacific herring. In other fish muscles, the selenium levels ranged between 0.12 and 0.77 mg/kg tissue. The selenium levels were closely correlated with the mercury levels in the white and red muscles in alfonsino. The selenium content in spleen, blood, hepatopancreas, heart, red muscle, white muscle, brain, ovary and testis ranged between 1.10 and 24.8 mg/kg tissue in alfonsino. PMID:23434904

  4. How humans drive speciation as well as extinction

    PubMed Central

    Maron, M.

    2016-01-01

    A central topic for conservation science is evaluating how human activities influence global species diversity. Humanity exacerbates extinction rates. But by what mechanisms does humanity drive the emergence of new species? We review human-mediated speciation, compare speciation and known extinctions, and discuss the challenges of using net species diversity as a conservation objective. Humans drive rapid evolution through relocation, domestication, hunting and novel ecosystem creation—and emerging technologies could eventually provide additional mechanisms. The number of species relocated, domesticated and hunted during the Holocene is of comparable magnitude to the number of observed extinctions. While instances of human-mediated speciation are known, the overall effect these mechanisms have upon speciation rates has not yet been quantified. We also explore the importance of anthropogenic influence upon divergence in microorganisms. Even if human activities resulted in no net loss of species diversity by balancing speciation and extinction rates, this would probably be deemed unacceptable. We discuss why, based upon ‘no net loss’ conservation literature—considering phylogenetic diversity and other metrics, risk aversion, taboo trade-offs and spatial heterogeneity. We conclude that evaluating speciation alongside extinction could result in more nuanced understanding of biosphere trends, clarifying what it is we actually value about biodiversity. PMID:27358365

  5. How humans drive speciation as well as extinction.

    PubMed

    Bull, J W; Maron, M

    2016-06-29

    A central topic for conservation science is evaluating how human activities influence global species diversity. Humanity exacerbates extinction rates. But by what mechanisms does humanity drive the emergence of new species? We review human-mediated speciation, compare speciation and known extinctions, and discuss the challenges of using net species diversity as a conservation objective. Humans drive rapid evolution through relocation, domestication, hunting and novel ecosystem creation-and emerging technologies could eventually provide additional mechanisms. The number of species relocated, domesticated and hunted during the Holocene is of comparable magnitude to the number of observed extinctions. While instances of human-mediated speciation are known, the overall effect these mechanisms have upon speciation rates has not yet been quantified. We also explore the importance of anthropogenic influence upon divergence in microorganisms. Even if human activities resulted in no net loss of species diversity by balancing speciation and extinction rates, this would probably be deemed unacceptable. We discuss why, based upon 'no net loss' conservation literature-considering phylogenetic diversity and other metrics, risk aversion, taboo trade-offs and spatial heterogeneity. We conclude that evaluating speciation alongside extinction could result in more nuanced understanding of biosphere trends, clarifying what it is we actually value about biodiversity. PMID:27358365

  6. Reduced expressions of calmodulin genes and protein and reduced ability of calmodulin to activate plasma membrane Ca(2+) -ATPase in the brain of protein undernourished rats: modulatory roles of selenium and zinc supplementation.

    PubMed

    Adebayo, Olusegun L; Khera, Alka; Sandhir, Rajat; Adenuga, Gbenga A

    2016-03-01

    The roles of protein undernutrition as well as selenium (Se) and zinc (Zn) supplementation on the ability of calmodulin (CaM) to activate erythrocyte ghost membrane (EGM) Ca(2+) -ATPase and the calmodulin genes and protein expressions in rat's cortex and cerebellum were investigated. Rats on adequate protein diet and protein-undernourished (PU) rats were fed with diet containing 16% and 5% casein, respectively, for a period of 10 weeks. The rats were then supplemented with Se and Zn at a concentration of 0.15 and 227 mg l(-1) , respectively, in drinking water for 3 weeks. The results obtained from the study showed significant reductions in synaptosomal plasma membrane Ca(2+) -ATPase (PMCA) activity, Ca(2+) /CaM activated EGM Ca(2+) ATPase activity and calmodulin genes and protein expressions in PU rats. Se or Zn supplementation improved the ability of Ca(2+) /CaM to activate EGM Ca(2+) -ATPase and protein expressions. Se or Zn supplementation improved gene expression in the cerebellum but not in the cortex. Also, the activity of PMCA was significantly improved by Zn. In conclusion, it is postulated that Se and Zn might be beneficial antioxidants in protecting against neuronal dysfunction resulting from reduced level of calmodulin such as present in protein undernutrition. Copyright © 2016 John Wiley & Sons, Ltd. PMID:26879852

  7. Shedding Light on Selenium Biomineralization: Proteins Associated with Bionanominerals ▿

    PubMed Central

    Lenz, Markus; Kolvenbach, Boris; Gygax, Benjamin; Moes, Suzette; Corvini, Philippe F. X.

    2011-01-01

    Selenium-reducing microorganisms produce elemental selenium nanoparticles with particular physicochemical properties due to an associated organic fraction. This study identified high-affinity proteins associated with such bionanominerals and with nonbiogenic elemental selenium. Proteins with an anticipated functional role in selenium reduction, such as a metalloid reductase, were found to be associated with nanoparticles formed by one selenium respirer, Sulfurospirillum barnesii. PMID:21602371

  8. Selenium Characterization in the Global Rice Supply Chain

    SciTech Connect

    Williams, Paul N.; Lombi, Enzo; Sun, Guo-Xin; Scheckel, Kirk; Zhu, Yong-Guan; Feng, Xinbin; Zhu, Jianming; Carey, Anne-Marie; Adomako, Eureka; Lawgali, Youseff; Deacon, Claire; Meharg, Andrew A.

    2009-08-13

    For up to 1 billion people worldwide, insufficient dietary intake of selenium (Se) is a serious health constraint. Cereals are the dominant Se source for those on low protein diets, as typified by the global malnourished population. With crop Se content constrained largely by underlying geology, regional soil Se variations are often mirrored by their locally grown staples. Despite this, the Se concentrations of much of the world's rice, the mainstay of so many, is poorly characterized, for both total Se content and Se speciation. In this study, 1092 samples of market sourced polished rice were obtained. The sampled rice encompassed dominant rice producing and exporting countries. Rice from the U.S. and India were found to be the most enriched, while mean average levels were lowest in Egyptian rice: {approx}32-fold less than their North American equivalents. By weighting country averages by contribution to either global production or export, modeled baseline values for both were produced. Based on a daily rice consumption of 300 g day{sup -1}, around 75% of the grains from the production and export pools would fail to provide 70% of daily recommended Se intakes. Furthermore, Se localization and speciation characterization using X-ray fluorescence ({mu}-XRF) and X-ray absorption near edge structure ({mu}-XANES) techniques were investigated in a Se-rich sample. The results revealed that the large majority of Se in the endosperm was present in organic forms.

  9. Selenium accumulation in flowers and its effects on pollination.

    PubMed

    Quinn, Colin F; Prins, Christine N; Freeman, John L; Gross, Amanda M; Hantzis, Laura J; Reynolds, Ray J B; Yang, Soo in; Covey, Paul A; Bañuelos, Gary S; Pickering, Ingrid J; Fakra, Sirine C; Marcus, Matthew A; Arathi, H S; Pilon-Smits, Elizabeth A H

    2011-11-01

    Selenium (Se) hyperaccumulation has a profound effect on plant-arthropod interactions. Here, we investigated floral Se distribution and speciation in flowers and the effects of floral Se on pollen quality and plant-pollinator interactions. • Floral Se distribution and speciation were compared in Stanleya pinnata, an Se hyperaccumulator, and Brassica juncea, a comparable nonhyperaccumulator. Pollen germination was measured from plants grown with varying concentrations of Se and floral visitation was compared between plants with high and low Se. • Stanleya pinnata preferentially allocated Se to flowers, as nontoxic methyl-selenocysteine (MeSeCys). Brassica juncea had higher Se concentrations in leaves than flowers, and a lower fraction of MeSeCys. For B. juncea, high floral Se concentration impaired pollen germination; in S. pinnata Se had no effect on pollen germination. Floral visitors collected from Se-rich S. pinnata contained up to 270 μg g(-1), concentrations toxic to many herbivores. Indeed, floral visitors showed no visitation preference between high- and low-Se plants. Honey from seleniferous areas contained 0.4-1 μg Se g(-1), concentrations that could provide human health benefits. • This study is the first to shed light on the possible evolutionary cost, through decreased pollen germination in B. juncea, of Se accumulation and has implications for the management of seleniferous areas. PMID:21793829

  10. Quantification of Methylated Selenium, Sulfur, and Arsenic in the Environment

    PubMed Central

    Vriens, Bas; Ammann, Adrian A.; Hagendorfer, Harald; Lenz, Markus; Berg, Michael; Winkel, Lenny H. E.

    2014-01-01

    Biomethylation and volatilization of trace elements may contribute to their redistribution in the environment. However, quantification of volatile, methylated species in the environment is complicated by a lack of straightforward and field-deployable air sampling methods that preserve element speciation. This paper presents a robust and versatile gas trapping method for the simultaneous preconcentration of volatile selenium (Se), sulfur (S), and arsenic (As) species. Using HPLC-HR-ICP-MS and ESI-MS/MS analyses, we demonstrate that volatile Se and S species efficiently transform into specific non-volatile compounds during trapping, which enables the deduction of the original gaseous speciation. With minor adaptations, the presented HPLC-HR-ICP-MS method also allows for the quantification of 13 non-volatile methylated species and oxyanions of Se, S, and As in natural waters. Application of these methods in a peatland indicated that, at the selected sites, fluxes varied between 190–210 ng Se·m−2·d−1, 90–270 ng As·m−2·d−1, and 4–14 µg S·m−2·d−1, and contained at least 70% methylated Se and S species. In the surface water, methylated species were particularly abundant for As (>50% of total As). Our results indicate that methylation plays a significant role in the biogeochemical cycles of these elements. PMID:25047128

  11. Methylselenol, a Selenium Metabolite, Plays Common and Different Roles in Colonic Cancer and Nontumorigenic Colonic Cell Growth

    Technology Transfer Automated Retrieval System (TEKTRAN)

    There is increasing evidence for the efficacy of certain forms of selenium (Se) as cancer-chemopreventive compounds, and methylselenol has been hypothesized to be a critical selenium metabolite for anticancer activity in vivo. To determine differential chemopreventive effects of methylselenol on col...

  12. Localized polyselenides in a graphene-coated polymer separator for high rate and ultralong life lithium-selenium batteries.

    PubMed

    Fang, Ruopian; Zhou, Guangmin; Pei, Songfeng; Li, Feng; Cheng, Hui-Ming

    2015-02-28

    A graphene-coated polymer separator was developed for lithium-selenium batteries with pure selenium powder as the active material. The structure is a simple yet effective strategy for improving Li-Se battery's electrochemical performance, yielding long cycle life up to 1000 cycles with high capacity and excellent rate behavior. PMID:25643659

  13. Effect of in ovo injection with selenium on immune and antioxidant responses during experimental necrotic enteritis in broiler chickens

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Selenium (Se) is an essential component of several major metabolic pathways in the antioxidant enzymes activity and modulating immune system. This study was conducted to investigate the effects of in ovo injection of selenium (Se) on modulating the immune system and antioxidant responses in chickens...

  14. Selenium inhibits the phytotoxicity of mercury in garlic (Allium sativum)

    SciTech Connect

    Zhao, Jiating; Gao, Yuxi; Li, Yu-Feng; Hu, Yi; Peng, Xiaomin; Dong, Yuanxing; Li, Bai; Chen, Chunying; Chai, Zhifang

    2013-08-15

    To investigate the influence of selenium on mercury phytotoxicity, the levels of selenium and mercury were analyzed with inductively coupled plasma-mass spectrometry (ICP-MS) in garlic tissues upon exposure to different dosages of inorganic mercury (Hg{sup 2+}) and selenite (SeO{sub 3}{sup 2−}) or selenate (SeO{sub 4}{sup 2−}). The distributions of selenium and mercury were examined with micro-synchrotron radiation X-ray fluorescence (μ-SRXRF), and the mercury speciation was investigated with micro-X-ray absorption near edge structure (μ-XANES). The results show that Se at higher exposure levels (>1 mg/L of SeO{sub 3}{sup 2−} or SeO{sub 4}{sup 2−}) would significantly inhibit the absorption and transportation of Hg when Hg{sup 2+} levels are higher than 1 mg/L in culture media. SeO{sub 3}{sup 2−} and SeO{sub 4}{sup 2−} were found to be equally effective in reducing Hg accumulation in garlic. The inhibition of Hg uptake by Se correlates well with the influence of Se on Hg phytotoxicity as indicated by the growth inhibition factor. Elemental imaging using μ-SRXRF also shows that Se could inhibit the accumulation and translocation of Hg in garlic. μ-XANES analysis shows that Hg is mainly present in the forms of Hg–S bonding as Hg(GSH){sub 2} and Hg(Met){sub 2}. Se exposure elicited decrease of Hg–S bonding in the form of Hg(GSH){sub 2}, together with Se-mediated alteration of Hg absorption, transportation and accumulation, may account for attenuated Hg phytotoxicity by Se in garlic. -- Highlights: ► Hg phytotoxicity can be mitigated by Se supplement in garlic growth. ► Se can inhibit the accumulation and transportation of Hg in garlic tissues. ► Localization and speciation of Hg in garlic can be modified by Se.

  15. SPECIATE 4.0: SPECIATION DATABASE DEVELOPMENT DOCUMENTATION--FINAL REPORT

    EPA Science Inventory

    SPECIATE is the U.S. EPA's repository of total organic compounds (TOC) and particulate matter (PM) speciation profiles of air pollution sources. This report documents how EPA developed the SPECIATE 4.0 database that replaces the prior version, SPECIATE 3.2. SPECIATE 4.0 includes ...

  16. Identification and characterization of a selenium-dependent glutathione peroxidase in Setaria cervi

    SciTech Connect

    Singh, Anchal; Rathaur, Sushma . E-mail: sushmarathaur@yahoo.com

    2005-06-17

    Setaria cervi a bovine filarial parasite secretes selenium glutathione peroxidase during in vitro cultivation. A significant amount of enzyme activity was detected in the somatic extract of different developmental stages of the parasite. Among different stages, microfilariae showed a higher level of selenium glutathione peroxidase activity followed by males then females. However, when the activity was compared in excretory secretory products of these stages males showed higher activity than microfilariae and female worms. The enzyme was purified from female somatic extract using a combination of glutathione agarose and gel filtration chromatography, which migrated as a single band of molecular mass {approx}20 kDa. Selenium content of purified enzyme was estimated by atomic absorption spectroscopy and found to be 3.5 ng selenium/{mu}g of protein. Further, inhibition of enzyme activity by potassium cyanide suggested the presence of selenium at the active site of enzyme. This is the first report of identification of selenium glutathione peroxidase from any filarial parasite.

  17. Aqueous extracts of selenium-fertilized broccoli increase selenoprotein activity and inhibit DNA single-strand breaks, but decrease the activity of quinone reductase in Hepa 1c1c7 cells.

    PubMed

    Keck, Anna-Sigrid; Finley, John W

    2006-05-01

    Depending on growth conditions, broccoli may be enriched in the isothiocyanate sulforaphane and/or the mineral selenium (Se); both compounds may play an important role in the reduction of intracellular oxidative stress and chronic disease prevention. Sulforaphane up-regulates transcription of Phase II detoxification proteins (e.g. quinone reductase [QR]), whereas Se is needed for the production of thioredoxin reductase (TR) and glutathione peroxidase-1 (GPx1), both of which exhibit antioxidant activity. The objective of the present study was to determine whether the fertilization of broccoli with Se increases the antioxidant ability of broccoli. Hydrogen peroxide-induced DNA single-strand breaks (measured by single cell electrophoresis, Comet assay) and activity of antioxidant enzymes (GPx, TR and QR) were measured in mouse hepatoma cells (Hepa 1c1c7 cells) treated with purified sulforaphane, sodium selenite or extracts of selenized broccoli. When supplied separately as chemically pure substances, sodium selenite was more effective than sulforaphane for reduction of single-strand breaks. Se-fertilized broccoli extracts were the most effective for reduction of DNA single-strand breaks, and extracts that contained 0.71 microM Se and 0.08 microM sulforaphane inhibited 94% of DNA single-strand breaks. A significant positive association (r = 0.81, p = 0.009) between GPx1 activity and inhibition of DNA single-strand breaks as well as a 24h lag time between addition of Se, sulforaphane or broccoli extract and inhibition of single-strand breaks suggests that some of the antioxidant protection is mediated through selenoproteins. Conversely, fertilization of broccoli with Se decreased the ability of broccoli extract to induce QR activity. These results demonstrate that Se and sulforaphane, alone or as a component of broccoli, may help decrease oxidative stress. They further suggest that Se is the most important for decreasing oxidative stress, but maximizing the Se content

  18. Can selenium levels act as a marker of colorectal cancer risk?

    PubMed Central

    2013-01-01

    Background Selenium has attracted attention because of its antioxidant properties. Antioxidants protects cells from damage. Certain breakdown products of selenium are believed to prevent tumor growth by enhancing the immune cell activity and suppressing the development of tumor blood vessels. In this observational study, selenium level was measured in a series of patients from Poland and Estonia to determine a correlation between levels of this microelement and colorectal cancer risk. Methods A total of 169 colorectal cancer patients and 169 healthy controls were enrolled in the study after obtaining their informed consent. Selenium level in the blood serum was measured using Graphite Furnace Atomic Absorption Spectrometry (GFAAS). The statistical analysis was performed by Fisher’s exact test. Results The threshold point of selenium level was 55 μg/l and 65 μg/l for Poland and Estonia respectively, for an increase in cancer risk. The lower levels of selenium were associated with greater risk of colorectal cancer. Conclusions The result reveals a significant strong association between low selenium level and the colorectal cancer risk in both Estonian and Polish populations. PMID:23627542

  19. Association between Toenail Mercury and Metabolic Syndrome Is Modified by Selenium

    PubMed Central

    Park, Kyong; Seo, Eunmin

    2016-01-01

    Background: Although Asian populations consume relatively large amounts of fish and seafood and have a high prevalence of metabolic diseases, few studies have investigated the association between chronic mercury exposure and metabolic syndrome and its effect modification by selenium. Methods: We analyzed baseline data from the Trace Element Study of Korean Adults in the Yeungnam area. Participants included 232 men and 269 women, aged 35 years or older, who had complete data regarding demographic, lifestyle, diet, toenail mercury and selenium levels, and health. Toenail mercury and selenium concentrations were measured using instrumental neutron-activation analysis. The metabolic biomarker levels were obtained through biannual medical checkups. Results: Higher toenail mercury levels were associated with habitual consumption of whale and shark meats, older age, obesity, smoking, alcohol drinking, and higher household income. Multivariable analysis showed a positive association between toenail mercury exposure and metabolic syndrome. In addition, this association was significantly stronger at lower selenium levels and was weaker at higher selenium levels. Conclusion: The possible harmful effects of mercury on metabolic syndrome may be attenuated by high levels of selenium. Future studies are needed to suggest optimal dietary guidelines regarding fish and selenium intakes, particularly for Asians with high levels of fish intake. PMID:27420091

  20. Longitudinal association between toenail selenium levels and measures of subclinical atherosclerosis: the CARDIA trace element study

    PubMed Central

    Xun, Pengcheng; Liu, Kiang; Morris, J Steven; Daviglus, Martha L; He, Ka

    2010-01-01

    Objectives To examine the longitudinal association between toenail selenium levels and sub-clinical atherosclerosis over an 18-year period. Methods Toenail selenium concentrations were examined among 3112 Americans age 20–32 years in 1987 and measured by instrumental neutron-activation analysis. Subclinical atherosclerosis, including common, bulb and internal carotid intima-media thickness (CIMT), was measured in 2005 and coronary artery calcium (CAC) score in 2000 and 2005. General linear regression was developed examining the relation between toenail selenium levels and CIMTs, and logistic regression for repeated outcomes was employed estimating the risk of having CAC>0. Results After adjustment for potential confounders, no associations were observed between toenail selenium levels and CIMTs as well as CAC score. Comparing participants in the highest with the lowest quintile of selenium, the CIMT was 0.005mm (SE=0.008mm, Ptrend=0.39), 0.018mm (SE=0.019mm, Ptrend=0.49), and 0.017mm (SE=0.014mm, Ptrend=0.21) thicker measured in common, bulb and internal carotid, respectively. The adjusted odds ratio of having CAC>0 was 0.95 (95%CI: 0.67–1.35; Ptrend=0.999). Conclusions No associations were observed between toenail selenium and measures of subclinical atherosclerosis among American young adults. This study does not support an atherosclerotic mechanism of selenium for risk reduction of cardiovascular disease. PMID:20138620

  1. Effects of selenium on 7,12-dimethylbenz(a)anthracene-induced mammary carcinogenesis and DNA adduct formation

    SciTech Connect

    Ip, C.; Daniel, F.B.

    1985-01-01

    The purpose of the present investigation was to determine the effects of dietary selenium deficiency or excess on 7,12-dimethylbenz(a)anthracene (DMBA)-induced mammary neoplasia in rats and to delineate whether selenium-mediated modification of mammary carcinogenesis was associated with changes in carcinogen:DNA adduct formation and activities of liver microsomal enzymes that are involved in xenobiotic metabolism. Female Sprague-Dawley rats were divided into three groups from weaning and were maintained on one of three synthetic diets designated as follows: selenium deficient (less than 0.02 ppm); selenium adequate (0.2 ppm); or selenium excess (2.5 ppm). For the DMBA binding and DNA adduct studies, rats were given a dose of (/sup 3/H)DMBA p.o. after 1 month on their respective diets. Results from the liver and the mammary gland indicated that neither selenium deficiency nor excess had any significant effect on the binding levels, which were calculated on the basis of total radioactivity isolated with the purified DNA. Furthermore, it was found that dietary selenium intake did not seem to affect quantitatively or qualitatively the formation of DMBA:DNA adducts in the liver. Similarly, in a parallel group of rats that did not receive DMBA, the activities of aniline hydroxylase, aminopyrine N-demethylase, and cytochrome c reductase were not significantly altered by dietary selenium levels. Concurrent with the above experiments, the effect of dietary selenium intake on carcinogenesis was also monitored. Results of this experiment indicated that selenium deficiency enhanced mammary carcinogenesis only when this nutritional condition was maintained in the postinitiation phase. Likewise, an excess of selenium intake inhibited neoplastic development only when this regimen was continued after DMBA administration.

  2. Clinical applications of HPLC-ICP-MS element speciation: A review.

    PubMed

    Delafiori, Jeany; Ring, Gavin; Furey, Ambrose

    2016-06-01

    Arsenic (As), Selenium (Se) and Mercury (Hg) are three trace elements that have been the subject of much analytical discussion and investigation over the last three decades. While Selenium (Se) is among the list of essential trace elements necessary for the regulation of metabolic processes and overall health, As and Hg are not, and have been the centre of various cases surrounding the contamination of food, water and the environment. The focus of this review is to explore the area of chemical speciation, particularly as it relates to the measurement of these elements in various clinical matrices by HPLC-ICP-MS. This review will highlight the importance of accurately identifying the various chemical species of each of these elements, especially when considering their respective toxicological impacts on human health. PMID:27130123

  3. Will selenium increase lentil (Lens culinaris Medik) yield and seed quality?

    PubMed

    Thavarajah, Dil; Thavarajah, Pushparajah; Vial, Eric; Gebhardt, Mary; Lacher, Craig; Kumar, Shiv; Combs, Gerald F

    2015-01-01

    Lentil (Lens culinaris Medik), a nutritious traditional pulse crop, has been experiencing a declining area of production in South East Asia, due to lower yields, and marginal soils. The objective of this study was to determine whether selenium (Se) fertilization can increase lentil yield, productivity, and seed quality (both seed Se concentration and speciation). Selenium was provided to five lentil accessions as selenate or selenite by foliar or soil application at rates of 0, 10, 20, or 30 kg Se/ha and the resulting lentil biomass, grain yield, seed Se concentration, and Se speciation was determined. Seed Se concentration was measured using inductively coupled plasma optical emission spectrometry (ICP-OES) after acid digestion. Seed Se speciation was measured using ICP-mass spectrometry with a high performance liquid chromatography (ICP-MS-LC) system. Foliar application of Se significantly increased lentil biomass (5586 vs. 7361 kg/ha), grain yield (1732 vs. 2468 kg /ha), and seed Se concentrations (0.8 vs. 2.4 μg/g) compared to soil application. In general, both application methods and both forms of Se increased concentrations of organic Se forms (selenocysteine and selenomethionine) in lentil seeds. Not surprisingly, the high yielding CDC Redberry had the highest levels of biomass and grain yield of all varieties evaluated. Eston, ILL505, and CDC Robin had the greatest responses to Se fertilization with respect to both grain yield, seed Se concentration and speciation; thus, use of these varieties in areas with low-Se soils might require Se fertilization to reach yield potentials. PMID:26042141

  4. Selenium and arsenic in biology: their chemical forms and biological functions.

    PubMed

    Shibata, Y; Morita, M; Fuwa, K

    1992-01-01

    Based on the recent development of analytical methods, sensitive systems for the analysis and speciation of selenium and arsenic have been established. A palladium addition technique was developed for the accurate determination of selenium in biological samples using graphite furnace atomic absorption analysis. For the speciation of the elements, combined methods of HPLC either with ICP-AES or with ICP-MS were found to work well. These systems were applied to the elucidation of the chemical form of the elements in natural samples. Some chemical properties of the selenium-mercury complex in dolphin liver were elucidated: i.e., it was a cationic, water-soluble, low molecular weight compound containing selenium and mercury in a 1:1 molar ratio, and was shown to be different from a known selenium-mercury complex, bis(methylmercuric)selenide. The major selenium compound excreted in human urine was revealed to be other than any of those previously identified (TMSe, selenate, and selenite). TMSe, a suspected major metabolite in urine, was found, if at all, in low levels. The major water-soluble, and lipid-soluble arsenic compounds in a brown seaweed, U. pinnatifida (WAKAME), were rigorously identified, and the results were compared with other data on marine algae and animals. The major organic arsenic compounds (termed "arseno-sugars") in marine algae commonly contain 5-deoxy-5-dimethylarsinyl-ribofuranoside moiety. There are various kinds of arseno-sugar derivatives containing different side-chains attached to the anomeric position of the sugar, and the distribution of each arsenic species seems to be related to algal species. The arseno-sugar (A-XI) is present in every alga so far examined, is metabolized to lipids, and possibly may play some specific role in the algal cells. On the other hand, the major arsenic compound in fish, crustacea and molluscs has been identified as arsenobetaine, which is an arseno-analog of glycinebetaine, a very common osmo-regulator in

  5. Selenium mediated reduction of the toxicity expression of cigarette smoke condensate in Photobacterium phosphoreum

    SciTech Connect

    Yates, I.E.; Chortyk, O.T.; Lanier, J.L.

    1986-02-01

    Recently, attention has focused on the potential protective activity of selenium against heavy metal toxicity, cancer and other health disorders. Currently, cigarette smoke affects the health of more people than any other environmental pollutant. Producing cigarettes fortified with selenium has been proposed as a possible method to develop a safer tobacco product. Consequently, it would be informative to determine if the presence of selenium in cigarette smoke leads to increased or decreased toxicity. Luminescent assays have been developed for a wide variety of applications ranging from measuring enzyme activities to monitoring water purity. The purpose of this study was to evaluate the effect of selenium on the toxicity of cigarette smoke condensate using in vivo bacterial bioluminescence assays.

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

    SciTech Connect

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

    2009-06-04

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

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

    PubMed

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

    2015-07-01

    Three month old Thunbergia alata were exposed for 13 days to 10 μM selenite to determine the biotransformation of selenite in their roots. Selenium in formic acid extracts (80 ± 3%) was present as selenopeptides with Se-S bonds and selenium-PC complexes (selenocysteinyl-2-3-dihydroxypropionyl-glutathione, seleno-phytochelatin2, seleno-di-glutathione). An analytical method using HPLC-ICPMS to detect and quantify elemental selenium in roots of T. alata plants using sodium sulfite to quantitatively transform elemental selenium to selenosulfate was also developed. Elemental selenium was determined as 18 ± 4% of the total selenium in the roots which was equivalent to the selenium not extracted using formic acid extraction. The results are in an agreement with the XAS measurements of the exposed roots which showed no occurrence of selenite or selenate but a mixture of selenocysteine and elemental selenium. PMID:25747595

  8. 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.

  9. Selenium toxicosis in wild aquatic birds.

    PubMed

    Ohlendorf, H M; Kilness, A W; Simmons, J L; Stroud, R K; Hoffman, D J; Moore, J F

    1988-01-01

    Severe gross and microscopic lesions and other changes were found in adult aquatic birds and in embryos from Kesterson Reservoir (a portion of Kesterson National Wildlife Refuge), Merced County, Calif., during 1984. Adult birds from that area were emaciated, had subacute to extensive chronic hepatic lesions, and had excess fluid and fibrin in the peritoneal cavity. Biochemical changes in their livers included elevated glycogen and non-protein-bound sulfhydryl concentrations and glutathione peroxidase activity but lowered protein, total sulfhydryl, and protein-bound sulfhydryl concentrations. Congenital malformations observed grossly in embryos were often multiple and included anophthalmia, microphthalmia, abnormal beaks, amelia, micromelia, ectrodactyly, and hydrocephaly. Mean concentrations of selenium in livers (94.4 ppm, dry weight) and kidneys (96.6 ppm) of birds collected at the Kesterson ponds were about 10 times those found at a nearby control area (8.3 and 12.2 ppm). We conclude that selenium present in the agricultural drainage water supplied to the Kesterson ponds accumulated in the food chain of aquatic birds to toxic concentrations and caused the lesion and other changes observed. PMID:3373565

  10. Selenium Metabolism in Neptunia amplexicaulis1

    PubMed Central

    Burnell, James N.

    1981-01-01

    ATP sulfurylase (EC 2.7.7.4), cysteinyl-tRNA synthetase (EC 6.1.1.16), and methionyl-tRNA synthetase (EC 6.1.1.10) from Neptunia amplexicaulis have been purified approximately 162-, 140- and 185-fold, respectively. Purified ATP sulfurylase in the presence of purified inorganic pyrophosphatase catalyzed the incorporation of sulfate into adenosine 5′-phosphosulfate; evidence of an analogous reaction with selenate is presented. Crude extracts catalyzed both the sulfate- and the adenosine 5′-phosphosulfate-dependent NADH oxidation in the adenosine 5′-phosphosulfate kinase assay of Burnell and Whatley (1977 Biochim Biophys Acta 481: 266-278), but an analogous reaction with selenate could not be detected. Both purified cysteinyl-tRNA synthetase and methionyl-tRNA synthetase used selenium-containing analogs as substrates in both the ATP-pyrophosphate exchange and the aminoacylation assays. It seems that selenium-containing amino acids are excluded from proteins by a mechanism(s) other than substrate discrimination at the amino acid activation stage of protein synthesis. PMID:16661667

  11. Selenium toxicosis in wild aquatic birds

    SciTech Connect

    Ohlendorf, H.M.; Kilness, A.W.; Simmons, J.L.; Stroud, R.K.; Hoffman, D.J.; Moore, J.F.

    1988-01-01

    Severe gross and microscopic lesions and other changes were found in adult aquatic birds and in embryos from Kesterson Reservoir (a portion of Kesterson National Wildlife Refuge), Merced County, Calif., during 1984. Adult birds from that area were emaciated, had subacute to extensive chronic hepatic lesions, and had excess fluid and fibrin in the peritoneal cavity. Biochemical changes in their livers included elevated glycogen and non-protein-bound sulfhydryl concentrations and glutathione peroxidase activity but lowered protein, total sulfhydryl, and protein-bound sulfhydryl concentrations. Congenital malformations observed grossly in embryos were often multiple and included anophthalmia, microphthalmia, abnormal beaks, amelia, micromelia, ectrodactyly, and hydrocephaly. Mean concentrations of selenium in livers (94.4 ppm, dry weight) and kidneys (96.6 ppm) of birds collected at the Kesterson ponds were about 10 times those found at a nearby control area (8.3 and 12.2 ppm). We conclude that selenium present in the agricultural drainage water supplied to the Kesterson ponds accumulated in the food chain of aquatic birds to toxic concentrations and caused the lesion and other changes observed.

  12. Selenium and tellurium as carbon substitutes

    SciTech Connect

    Knapp, Jr., F. F.

    1980-01-01

    This review has summarized structure-activity studies with /sup 75/Se- and /sup 123m/Te-labeled radiopharmaceuticals in which the selenium or tellurium heteroatom has been inserted between carbon-carbon bonds. The agents that have been investigated in most detail include steroids for adrenal imaging and long-chain fatty acids, and a variety of other unique agents have also been studied. Because of the great versatility of the organic chemistry of selenium and tellurium, there is continuing interest in the preparation of radiopharmaceuticals labeled with /sup 75/Se, /sup 73/Se, and /sup 123m/Te. There are two important factors which will determine the extent of future interest in such agents. These include the necessity of a decrease in the cost of highly enriched /sup 122/Te to make the reactor production of /sup 123m/Te cost effective. In addition, the potential preparation of large amounts of /sup 73/Se should stimulate the development of /sup 73/Se-labeled radiopharmaceuticals.

  13. Daily dietary selenium intake and hair selenium content in a high selenium area of Enshi, China

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Selenium is essential to humans and is widely distributed within the human body. Its content in blood, urine, hair and nails are important indicators to evaluate Se level in the human body. In China (Shadi, Enschi city), human selenosis of residents is reported to occur in high numbers. In this stud...

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We determined the bioavailability of selenium (Se) from yellow peas and oats harvested from high-Se soil of South Dakota, United States. The Se concentrations of the peas and oats were 13.5 ± 0.2 and 2.5 ± 0.1 mg/kg, respectively. Male weanling Sprague-Dawley rats were depleted of Se by feeding them...

  15. CORRELATING METAL SPECIATION IN SOILS

    EPA Science Inventory

    Understanding bioavailability of metals from exposure to contaminated soils is a challenging aspect of environmental research. This presentation will examine three areas of research with respect to metal speciation in soils as it relates to bioavailability: 1) Pb immobilization a...

  16. High serum selenium levels are associated with increased risk for diabetes mellitus independent of central obesity and insulin resistance

    PubMed Central

    Lu, Chia-Wen; Chang, Hao-Hsiang; Yang, Kuen-Cheh; Kuo, Chia-Sheng; Lee, Long-Teng; Huang, Kuo-Chin

    2016-01-01

    Objective Selenium is an essential micronutrient for human health. Although many observational and interventional studies have examined the associations between selenium and diabetes mellitus, the findings were inconclusive. This study aimed to investigate the relationship between serum selenium levels and prevalence of diabetes, and correlated the relationship to insulin resistance and central obesity. Research design and methods This was a hospital-based case–control study of 847 adults aged more than 40 years (diabetes: non-diabetes =1:2) in Northern Taiwan. Serum selenium was measured by an inductively coupled plasma-mass spectrometer. The association between serum selenium and diabetes was examined using multivariate logistic regression analyses. Results After adjusting for age, gender, current smoking, current drinking, and physical activity, the ORs (95% CI, p value) of having diabetes in the second (Q2), third (Q3), and fourth (Q4) selenium quartile groups were 1.24 (95% CI 0.78 to 1.98, p>0.05), 1.90 (95% CI 1.22 to 2.97, p<0.05), and 5.11 (95% CI 3.27 to 8.00, p<0.001), respectively, compared with the first (Q1) quartile group. Further adjustments for waist circumference and homeostatic model assessment-insulin resistance (HOMA-IR) largely removed the association of serum selenium levels with diabetes but not in the highest quartile (compared with Q1, Q3: 1.57, 95% CI 0.91 to 2.70, Q4: 3.79, 95% CI 2.17 to 6.32). Conclusions We found that serum selenium levels were positively associated with prevalence of diabetes. This is the first human study to link insulin resistance and central obesity to the association between selenium and diabetes. Furthermore, the association between selenium and diabetes was independent of insulin resistance and central obesity at high serum selenium levels. The mechanism behind warrants further confirmation. PMID:27547419

  17. Floral symmetry affects speciation rates in angiosperms.

    PubMed Central

    Sargent, Risa D.

    2004-01-01

    Despite much recent activity in the field of pollination biology, the extent to which animal pollinators drive the formation of new angiosperm species remains unresolved. One problem has been identifying floral adaptations that promote reproductive isolation. The evolution of a bilaterally symmetrical corolla restricts the direction of approach and movement of pollinators on and between flowers. Restricting pollinators to approaching a flower from a single direction facilitates specific placement of pollen on the pollinator. When coupled with pollinator constancy, precise pollen placement can increase the probability that pollen grains reach a compatible stigma. This has the potential to generate reproductive isolation between species, because mutations that cause changes in the placement of pollen on the pollinator may decrease gene flow between incipient species. I predict that animal-pollinated lineages that possess bilaterally symmetrical flowers should have higher speciation rates than lineages possessing radially symmetrical flowers. Using sister-group comparisons I demonstrate that bilaterally symmetric lineages tend to be more species rich than their radially symmetrical sister lineages. This study supports an important role for pollinator-mediated speciation and demonstrates that floral morphology plays a key role in angiosperm speciation. PMID:15156918

  18. Selenium nanoparticles inhibit Staphylococcus aureus growth

    PubMed Central

    Tran, Phong A; Webster, Thomas J

    2011-01-01

    Staphylococcus aureus is a key bacterium commonly found in numerous infections. S. aureus infections are difficult to treat due to their biofilm formation and documented antibiotic resistance. While selenium has been used for a wide range of applications including anticancer applications, the effects of selenium nanoparticles on microorganisms remain largely unknown to date. The objective of this in vitro study was thus to examine the growth of S. aureus in the presence of selenium nanoparticles. Results of this study provided the first evidence of strongly inhibited growth of S. aureus in the presence of selenium nanoparticles after 3, 4, and 5 hours at 7.8, 15.5, and 31 μg/mL. The percentage of live bacteria also decreased in the presence of selenium nanoparticles. Therefore, this study suggests that selenium nanoparticles may be used to effectively prevent and treat S. aureus infections and thus should be further studied for such applications. PMID:21845045

  19. Recovering selenium from copper refinery slimes

    NASA Astrophysics Data System (ADS)

    Hyvärinen, Olli; Lindroos, Leo; Yllö, Erkki

    1989-07-01

    The selenium contained within copper refinery slimes may be recovered advantageously by roasting at about 600°C. While roasting in air is inefficient, roasting in a sulfating atmosphere enables practically complete selenium recovery. Based on laboratory tests, a new selenium recovery process was adopted at Outokumpu Copper Refinery. In this process, sulfation is achieved by feeding sulfur dioxide and oxygen into the roasting furnace.

  20. Antioxidant and cytotoxic effect of biologically synthesized selenium nanoparticles in comparison to selenium dioxide.

    PubMed

    Forootanfar, Hamid; Adeli-Sardou, Mahboubeh; Nikkhoo, Maryam; Mehrabani, Mitra; Amir-Heidari, Bagher; Shahverdi, Ahmad Reza; Shakibaie, Mojtaba

    2014-01-01

    The present study was designed to evaluate antioxidant and cytotoxic effect of selenium nanoparticles (Se NPs) biosynthesized by a newly isolated marine bacterial strain Bacillus sp. MSh-1. An organic-aqueous partitioning system was applied for purification of the biogenic Se NPs and the purified Se NPs were then investigated for antioxidant activity using DPPH scavenging activity and reducing power assay. Cytotoxic effect of the biogenic Se NPs and selenium dioxide (SeO2) on MCF-7 cell line was assesed by MTT assay. Tranmission electron micrograph (TEM) of the purified Se NPs showed individual and spherical nanostructure in size range of about 80-220nm. The obtained results showed that, at the same concentration of 200μg/mL, Se NPs and SeO2 represented scavenging activity of 23.1±3.4% and 13.2±3.1%, respectively. However, the data obtained from reducing power assay revealed higher electron-donating activity of SeO2 compared to Se NPs. Higher IC50 of the Se NPs (41.5±0.9μg/mL) compared to SeO2 (6.7±0.8μg/mL) confirmed lower cytotoxicity of the biogenic Se NPs on MCF-7 cell line. PMID:24074651

  1. Selenium status of idiopathic infertile Nigerian males.

    PubMed

    Akinloye, Oluyemi; Arowojolu, A O; Shittu, O B; Adejuwon, C A; Osotimehin, Babatunde

    2005-04-01

    Selenium concentration in the sera and seminal plasma of 60 infertile males (40 oligospermia and 20 azoospermia) and 40 males with proven evidence of fertility (normospermia; control group) were estimated using atomic absorption spectrophotometry. Results were correlated with spermatogram and hormonal levels in order to determine their relationship and significance in male infertility. The mean serum concentrations of selenium was found to be significantly increased in oligospermic compared to azoospermic subjects and controls (p < 0.01), whereas the seminal plasma level was significantly higher in azoospermic compared to oligospermic subjects and controls (p < 0.001). Thus, the ratio of serum selenium to seminal plasma selenium was 1: 1 in controls, 4: 1 in oligospermia, and 1: 2 in azoospermic subject.A significant inverse correlation was observed between serum selenium level and sperm count (p < 0.01). Similarly, seminal plasma selenium correlated with spermatozoa motility, viability, and morphology. Serum selenium level shows positive correlation with the serum testosterone level (p < 0.01). In conclusion, there appears to be a physiological balance in the distribution of selenium in serum and seminal plasma compartment of control males. A disturbance in this balance has a significant influence on spermatogenesis. Selenium appears to have a positive influence on Leydig cells, thus influencing the secretion of testosterone. PMID:15851828

  2. Selenium bioavailability with reference to human nutrition

    SciTech Connect

    Young, V.R.; Nahapetian, A.; Janghorbani, M.

    1982-05-01

    Various aspects of selenium metabolism and nutrition in relation to the question of selenium bioavailability in foods and the diet of man are reviewed. Few published studies exist on selenium metabolism in human subjects, particularly those representative of healthy individuals in the United States. Animal studies reveal that various factors, including the source and chemical form of selenium in foods and feeds, influence selenium bioavailability. However, the quantitative significance of animal assay data for human nutrition is not known. The limited number of published studies in man suggest that the metabolic fate and physiological function of dietary selenite may differ from that of selenomethionine or of food selenium. However, much additional research will be required to establish an adequate picture of the significance of dietary selenium bioavailability in human nutrition and health. Based on initial human experiments carried out at the Massachusetts Institute of Technology, use of stable isotopes of selenium offers promising opportunities for closing the gap of knowledge that now exists concerning the role and significance of factors that determine how the selenium present in foods is used to meet the physiological requirements of the consumer.

  3. Selenium levels in breads from Sakarya, Turkey.

    PubMed

    Gülfen, Mustafa

    2012-01-01

    Selenium (Se) is an important trace element for human and animal health. It accumulates in wheat and corn, which is consumed mostly as bread. The Turkish population consumes mainly white wheat, whole wheat (brown bread) and corn breads. In this study, samples of these breads were collected from six different bakeries in the city of Sakarya, and their selenium levels were determined by ICP-OES after a chemical digestion. It was found that average selenium levels in white wheat, whole wheat and corn breads were 1149, 1204 and 2023 µg/kg, respectively. The results are compared with daily recommended intake and upper tolerable levels for selenium. PMID:24779690

  4. Selenium. Nutritional, toxicologic, and clinical aspects.

    PubMed Central

    Fan, A. M.; Kizer, K. W.

    1990-01-01

    Despite the recent findings of environmental contamination, selenium toxicosis in humans is exceedingly rare in the United States, with the few known cases resulting from industrial accidents and an episode involving the ingestion of superpotent selenium supplements. Chronic selenosis is essentially unheard of in this country because of the typical diversity of the American diet. Nonetheless, because of the growing public interest in selenium as a dietary supplement and the occurrence of environmental selenium contamination, medical practitioners should be familiar with the nutritional, toxicologic, and clinical aspects of this trace element. PMID:2219873

  5. Removal of selenium from contaminated waters

    SciTech Connect

    Gleason, K.J.; Yu, Jianhan; Wright, J.D.

    1995-12-01

    Selenium, an essential nutrient in minute quantities, is known to be toxic and is a suspected carcinogen at higher concentrations. The toxicity and teratogenicity of selenium to waterfowl present difficulties in disposing of selenium contaminated waters. Included in the U.S. EPA`s list of priority pollutants, selenium is presently the primary water treatment challenge for many West Coast petroleum refineries. Depending on the type of crude oil processed, selenium can be found in refinery process waters at levels up to 5 mg/L with flowrates approaching 1000 gallons per minute. Agricultural drainage waters emanating from irrigated farm lands in the seleniferous areas of the western United States are another major source of selenium contaminated waters. Because of the high mobility of some selenium compounds, they are easily leached from these soils by irrigation water. Within central California alone, there is a current need for the treatment of about 2 million gallons per day of selenium contaminated agricultural drainage water in concentrations approaching 0.5 mg/L. This paper will present an improved process for the removal of selenium from contaminated waters.

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

    PubMed

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

    2007-12-01

    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

  7. 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

  8. Determination of selenium in fish from designated critical habitat of the Gunnison River, Colorado, summer 2011

    USGS Publications Warehouse

    May, Thomas W.; Walther, Michael J.

    2012-01-01

    This report presents results for the summer 2011 sampling of muscle plugs from common carps (Cyprinus Linnaeus), roundtail chub (Gila robusta), and bonytail chub (Gila elegans) inhabiting critical habitat in the Gunnison River in Western Colorado. Total selenium in fish muscle plugs was determined by instrumental neutron activation analysis. Total selenium concentrations (range and mean ± standard deviation) in micrograms per gram dry weight for each species were as follows: common carp: 8.5 to 35, 13 ± 7.8; roundtail chub: 5.5 to 11.2, 7.3 ± 1.6; bonytail chub: 0.8 to 8.6, 3.9 ± 4.2. Selenium concentrations in muscle plugs from 4 out of 15 roundtail chub, all 15 common carp, and 2 out of 5 bonytail chub exceeded the 8 micrograms per gram dry weight toxicity guideline for selenium in fish muscle tissue.

  9. Sexual conflict and speciation.

    PubMed Central

    Parker, G A; Partridge, L

    1998-01-01

    We review the significance of two forms of sexual conflict (different evolutionary interests of the two sexes) for genetic differentiation of populations and the evolution of reproductive isolation. Conflicting selection on the alleles at a single locus can occur in males and females if the sexes have different optima for a trait, and there are pleiotropic genetic correlations between the sexes for it. There will then be selection for sex limitation and hence sexual dimorphism. This sex limitation could break down in hybrids and reduce their fitness. Pleiotropic genetic correlations between the sexes could also affect the likelihood of mating in interpopulation encounters. Conflict can also occur between (sex-limited) loci that determine behaviour in males and those that determine behaviour in females. Reproductive isolation may occur by rapid coevolution of male trait and female mating preference. This would tend to generate assortative mating on secondary contact, hence promoting speciation. Sexual conflict resulting from sensory exploitation, polyspermy and the cost of mating could result in high levels of interpopulation mating. If females evolve resistance to make pre- and postmating manipulation, males from one population could be more successful with females from the other, because females would have evolved resistance to their own (but not to the allopatric) males. Between-locus sexual conflict could also occur as a result of conflict between males and females of different populations over the production of unfit hybrids. We develop models which show that females are in general selected to resist such matings and males to persist, and this could have a bearing on both the initial level of interpopulation matings and the likelihood that reinforcement will occur. In effect, selection on males usually acts to promote gene flow and to restrict premating isolation, whereas selection on females usually acts in the reverse direction. We review theoretical models

  10. Selenium deficiency and thyroid fibrosis. A key role for macrophages and transforming growth factor beta (TGF-beta).

    PubMed

    Contempre, B; Le Moine, O; Dumont, J E; Denef, J F; Many, M C

    1996-11-29

    Free radical damage and fibrosis caused by selenium deficiency are thought to be involved in the pathogenesis of myxoedematous cretinism. So far, no pathway explains the link between selenium deficiency and tissue fibrosis. Pharmacological doses of iodine induce necrosis in iodine-deficient thyroids. Necrosis is much increased if the glands are also selenium-deficient, which then evolve to fibrosis. This rat model was reproduced to explore the role of selenium deficiency in defective tissue repair. At first, proliferation indexes of epithelial cells and fibroblasts were comparable between selenium-deficient and control groups. Then, in selenium-deficient thyroids the inflammatory reaction was more marked being mainly composed of macrophages. The proliferation index of the epithelial cells decreased, while that of the fibroblasts increased. These thyroids evolved to fibrosis. TGF-beta immunostaining was prominent in the macrophages of selenium-deficient rats. Anti TGF-beta antibodies restored the proliferation indexes, and blocked the evolution to fibrosis. In selenium deficiency, an active fibrotic process occurs in the thyroid, in which the inflammatory reaction and an excess of TGF-beta play a key role. PMID:9027319

  11. Toxicokinetics of selenium in the slider turtle, Trachemys scripta.

    PubMed

    Dyc, Christelle; Far, Johann; Gandar, Frédéric; Poulipoulis, Anastassios; Greco, Anais; Eppe, Gauthier; Das, Krishna

    2016-05-01

    Selenium (Se) is an essential element that can be harmful for wildlife. However, its toxicity in poikilothermic amniotes, including turtles, remains poorly investigated. The present study aims at identifying selenium toxicokinetics and toxicity in juvenile slider turtles (age: 7 months), Trachemys scripta, dietary exposed to selenium, as selenomethionine SeMet, for eight weeks. Non-destructive tissues (i.e. carapace, scutes, skin and blood) were further tested for their suitability to predict selenium levels in target tissues (i.e. kidney, liver and muscle) for conservation perspective. 130 juvenile yellow-bellied slider turtles were assigned in three groups of 42 individuals each (i.e. control, SeMet1 and SeMet2). These groups were subjected to a feeding trial including an eight-week supplementation period SP 8 and a following 4-week elimination period EP 4 . During the SP8, turtles fed on diet containing 1.1 ± 0.04, 22.1 ± 1.0 and 45.0 ± 2.0 µg g(-1) of selenium (control, SeMet1 and SeMet2, respectively). During the EP4, turtles fed on non-supplemented diet. At different time during the trial, six individuals per group were sacrificed and tissues collected (i.e. carapace, scutes, skin, blood, liver, kidney, muscle) for analyses. During the SP8 (Fig. 1), both SeMet1 and SeMet2 turtles efficiently accumulated selenium from a SeMet dietary source. The more selenium was concentrated in the food, the more it was in the turtle body but the less it was removed from their tissues. Moreover, SeMet was found to be the more abundant selenium species in turtles' tissues. Body condition (i.e. growth in mass and size, feeding behaviour and activity) and survival of the SeMet1 and SeMet2 turtles seemed to be unaffected by the selenium exposure. There were clear evidences that reptilian species are differently affected by and sensitive to selenium exposure but the lack of any adverse effects was quite unexpected. Fig. 1 Design of the feeding trial. T, Time of

  12. Effects of selenium on UVA-induced lipid peroxidation in cultured human skin fibroblasts.

    PubMed

    Moysan, A; Morlière, P; Marquis, I; Richard, A; Dubertret, L

    1995-01-01

    The effect of selenium on the lethal action of ultraviolet radiations and on the lipid peroxidation induced by exposures to ultraviolet A (320-400 nm; 360 kJ.m-2) and ultraviolet B (290-320 nm; 2 kJ.m-2) have been measured in cultured human skin fibroblasts. The experiments have been performed with either pure selenium or a spring water containing selenium and other trace elements (zinc and strontium). For cells cultured in a standard medium containing 10% fetal calf serum, no effect of selenium or spring water addition to the culture medium was observed on the lethality or on the peroxidative process induced by ultraviolet A and B radiations. Concurrently, there was no detectable increase of the seleno-dependent glutathione peroxidase activity. For cells previously depleted in selenium by a culture in a medium containing only 2% serum, a protective effect of selenium can be detected. Depending on the fibroblast donor, we observed (1) a protective effect on lethality of dividing fibroblasts induced by ultraviolet A radiations, (2) a protective effect on lipid peroxidation induced by ultraviolet A radiations on dividing or quiescent fibroblasts and (3) an increase in glutathione peroxidase activity in fibroblasts. PMID:7632435

  13. Characterization of selenium-enriched mycelia of Catathelasma ventricosum and their antihyperglycemic and antioxidant properties.

    PubMed

    Liu, Yuntao; Li, Caiming; Luo, Xiaohu; Han, Guoquan; Xu, Shude; Niu, Fuge; Hu, Xinjie; Wu, Hejun; Zhang, Huimin

    2015-01-21

    This is the first report concerning the selenium enrichment of Catathelasma ventricosum mycelia. The selenium-containing proteins present in selenium-enriched mycelia (Se-MC) were identified using size-exclusion chromatography-inductively coupled plasma-mass spectrometry (SEC-ICP-MS). The selenium-containing amino acids liberated by hydrolysis of these proteins were identified using anion exchange-ICP-MS. Se-MC was found to contain selenoproteins with molecular weights ranging from 1.7 to 60.5 kDa. The main selenium-containing amino acids within them were selenomethionine and selenocysteine. Furthermore, Se-MC possessed excellent antihyperglycemic and antioxidant properties. Se-MC normalized biochemical parameters like insulin level, blood glucose level, body weight, and antioxidant enzyme activity in streptozocin-induced diabetic mice. It also inhibited the α-amylase and α-glucosidase activities present in in vitro gastric and intestinal models. In conclusion, Se-MC has the potential to serve as a dietary supplement of selenium, an antioxidant, or an ingredient for the formulation of nutraceuticals. PMID:25536291

  14. Arabidopsis hybrid speciation processes

    PubMed Central

    Schmickl, Roswitha; Koch, Marcus A.

    2011-01-01

    The genus Arabidopsis provides a unique opportunity to study fundamental biological questions in plant sciences using the diploid model species Arabidopsis thaliana and Arabidopsis lyrata. However, only a few studies have focused on introgression and hybrid speciation in Arabidopsis, although polyploidy is a common phenomenon within this genus. More recently, there is growing evidence of significant gene flow between the various Arabidopsis species. So far, we know Arabidopsis suecica and Arabidopsis kamchatica as fully stabilized allopolyploid species. Both species evolved during Pleistocene glaciation and deglaciation cycles in Fennoscandinavia and the amphi-Beringian region, respectively. These hybrid studies were conducted either on a phylogeographic scale or reconstructed experimentally in the laboratory. In our study we focus at a regional and population level. Our research area is located in the foothills of the eastern Austrian Alps, where two Arabidopsis species, Arabidopsis arenosa and A. lyrata ssp. petraea, are sympatrically distributed. Our hypothesis of genetic introgression, migration, and adaptation to the changing environment during the Pleistocene has been confirmed: We observed significant, mainly unidirectional gene flow between the two species, which has given rise to the tetraploid A. lyrata. This cytotype was able to escape from the narrow ecological niche occupied by diploid A. lyrata ssp. petraea on limestone outcrops by migrating northward into siliceous areas, leaving behind a trail of genetic differentiation. PMID:21825128

  15. The Role of Selenium in HIV Infection Cosby A Stone, Kosuke Kawai, Roland Kupka, Wafaie W Fawzi Harvard School of Public Health

    PubMed Central

    Stone, Cosby A; Kawai, Kosuke; Kupka, Roland; Fawzi, Wafaie W.

    2010-01-01

    HIV infection is a global disease that disproportionately burdens populations with nutritional vulnerabilities. Laboratory experiments have shown that selenium has an inhibitory effect on HIV in vitro through antioxidant effects of glutathione peroxidase and other selenoproteins. Numerous studies have reported low selenium status in HIV-infected individuals, and serum selenium concentration declines with disease progression. Some cohort studies have shown an association between selenium deficiency and progression to AIDS or mortality. In several randomized controlled trials, selenium supplementation has reduced hospitalizations, diarrheal morbidity, and improved CD4 cell counts, but the evidence remains mixed. Additional trials are recommended to study the effect of selenium supplementation on opportunistic infections, and other HIV disease related comorbidities in the context of highly active antiretroviral therapy in both developing and developed countries. PMID:20961297

  16. Speciation of triphenyltin compounds using Moessbauer spectroscopy. Final report

    SciTech Connect

    Eng, G.

    1993-11-01

    Organotin compounds have been used widely as the active agent in antifouling marine paints. Organotin compounds, i.e., tributyltin compounds (TBTs) and triphenyltin compounds (TPTs) have been found to be effective in preventing the unwanted attachment and development of aquatic organisms such as barnacles, sea grass and hydroids on ships, hulls and underwater surfaces. However, these organotin compounds have been found to be toxic to non-targeted marine species as well. While speciation of tributyltins in environmental water systems has received much attention in the literature, little information concerning the speciation of triphenyltins is found. Therefore, it would be important to study the fate of TPTs in the aquatic environment, particularly in sediments, both oxic and anoxic, in order to obtain speciation data. Since marine estuaries consist of areas with varying salinity and pH, it is important to investigate the speciation of these compounds under varying salinity conditions. In addition, evaluation of the speciation of these compounds as a function of pH would give an insight into how these compounds might interact with sediments in waters where industrial chemical run-offs can affect the pH of the estuarine environment. Finally, since organotins are present in both salt and fresh water environments, the speciation of the organotins in seawater and distilled water should also be studied. Moessbauer spectroscopy would provide a preferred method to study the speciation of triphenyltins as they leach from marine paints into the aquatic environment. Compounds used in this study are those triphenyltin compounds that are commonly incorporated into marine paints such as triphenyltin fluoride (TPTF), triphenyltin acetate (TPTOAc), triphenyltin chloride (TPTCl) and triphenyltin hydroxide (TPTOH).

  17. Plant selenium from soil and the atmosphere

    SciTech Connect

    Haygarth, P.M.; Jones, K.C.; Harrison, A.F.

    1995-07-01

    Transfer of selenium (Se) to pasture is important for prevention of Se deficiency in livestock, yet little is known about the relative importance of inputs to pasture from soil and the atmosphere. An isotope dilution method was used to assess quantitatively the importance of these inputs to ryegrass. Soil was labelled with {sup 75}Se and subjected to two field treatments that were untreated (pH 6.0) and limed (pH 7.0). After an initial period of equilibration, the specific activity of Se associated with unwashed leaves became lower than that of soil. This indicated that atmospheric Se had been deposited onto and possibly incorporated into the ryegrass. The percent contribution of {sup 75}Se in pasture leaves derived from the soil was 47% (pH 6.0) and 70% (pH 7.0), with, by inference, the remainder coming from the atmosphere. 23 refs., 1 fig., 4 tabs.

  18. Iron Speciation in Urban Dust

    SciTech Connect

    E Elzinga; Y Gao; J Fitts; R Tappero

    2011-12-31

    An improved understanding of anthropogenic impacts on ocean fertility requires knowledge of anthropogenic dust mineralogy and associated Fe speciation as a critical step toward developing Fe solubility models constrained by mineralogical composition. This study explored the utility of micro-focused X-ray absorption spectroscopy ({mu}-XAS) in characterizing the speciation of Fe in urban dust samples. A micro-focused beam of 10 x 7 {micro}m made possible the measurement of the Fe K edge XAS spectra of individual dust particles in the PM5.6 size fraction collected in Newark, New Jersey, USA. Spectral analysis indicated the presence of mixtures of Fe-containing minerals within individual dust particles; we observed significant magnetite content along with other Fe(III)-(hydr)oxide minerals which could not be conclusively identified. Our data indicate that detailed quantitative determination of Fe speciation requires extended energy scans to constrain the types and relative abundance of Fe species present. We observe heterogeneity in Fe speciation at the dust particle level, which underscores the importance of analyzing a statistically adequate number of particles within each dust sample. Where possible, {mu}-XAS measurements should be complemented with additional characterization techniques such as {mu}-XRD and bulk XAS to obtain a comprehensive picture of the Fe speciation in dust materials. X-ray microprobes should be used to complement bulk methods used to determine particle composition, methods that fail to record particle heterogeneity.

  19. Comparison of methods to determine selenium species in saturation extracts of soils from the western San Joaquin Valley, California

    USGS Publications Warehouse

    Fio, John L.; Fujii, Roger

    1988-01-01

    Undigested organic matter in some of the extracts inhibited selenium detection when using the digestion and Sep-Pac C18 methods, but the interference was removed by using the XAD-8 method. Combining XAD-8 resin and activated charcoal was an unacceptable method, because the activated charcoal removed selenite and selenate. Ninety-eight percent of the selenium in the extracts was selenate and about 100 percent of the isolated organic selenium was associated with the humic acid fraction of dissolved-organic matter.

  20. The role of selenium in cancer prevention

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This elucidation of the role of selenium in health occurred over the last six decades. This involved selenium first being found to be a toxicant, followed only later by its recognition as an essential nutrient. This pathway of discovery led to fundamental discoveries in metabolic biochemistry, vir...

  1. 21 CFR 573.920 - Selenium.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Selenium. 573.920 Section 573.920 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS FOOD ADDITIVES PERMITTED IN FEED AND DRINKING WATER OF ANIMALS Food Additive Listing § 573.920 Selenium. (a) Public Law...

  2. 21 CFR 573.920 - Selenium.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Selenium. 573.920 Section 573.920 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS FOOD ADDITIVES PERMITTED IN FEED AND DRINKING WATER OF ANIMALS Food Additive Listing § 573.920 Selenium. (a) Public Law...

  3. 21 CFR 573.920 - Selenium.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Selenium. 573.920 Section 573.920 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS FOOD ADDITIVES PERMITTED IN FEED AND DRINKING WATER OF ANIMALS Food Additive Listing § 573.920 Selenium. (a) Public Law...

  4. Changing selenium nutritional status of Chinese residents

    Technology Transfer Automated Retrieval System (TEKTRAN)

    China has been designated as one of 40 countries deficient in selenium (Se) according to the World Health Organization. Selenium concentrations in hair are commonly used to evaluate the Se level of the human body. Moreover, hair Se concentrations are significantly correlated with Se concentrations ...

  5. Evaluation of simultaneous reduction and transport of selenium in saturated soil columns

    NASA Astrophysics Data System (ADS)

    Guo, Lei; Frankenberger, William T.; Jury, William A.

    1999-03-01

    Speciation plays an important role in determining the overall leachability of selenium in soil. In this study we present a mathematical model and results of miscible displacement experiments that were conducted to evaluate simultaneous reduction and transport of selenate in saturated soil columns. The experiments were carried out in organic amended (compost manure or gluten) or unamended soil, with O2-sparged or nonsparged influent solution. In all columns, reduction of selenate was fast enough to produce selenite flux in the effluent and elemental Se in the soil profile during a mean residence time of ˜30 hours. Reduction was accelerated in the presence of organic amendments and under low O2 concentrations, resulting in an increased retardation of selenium transport as a whole. The results of our experiments show that although selenate does not sorb to solid surfaces during transport, it reduces rapidly to forms that are strongly retarded. On the basis of simulation with the consecutive reaction and transport model using parameters derived from this study, selenium is expected to be retained near the soil surface, even under extreme leaching conditions.

  6. The chemical forms of mercury and selenium in whale skeletal muscle

    PubMed Central

    George, Graham N.; MacDonald, Tracy C.; Korbas, Malgorzata; Singh, Satya P.; Myers, Gary J.; Watson, Gene E.; O'Donoghue, John L.; Pickering, Ingrid J.

    2013-01-01

    Human exposure to potentially neurotoxic methylmercury species is a public-health concern for many populations worldwide. Both fish and whale are known to contain varying amounts of methylmercury species. However studies of populations that consume large quantities of fish or whale have provided no clear consensus as to the extent of the risk. The toxicological profile of an element depends strongly on its chemical form. We have used X-ray absorption spectroscopy to investigate the comparative chemical forms of mercury and selenium in fish and whale skeletal muscle. The predominant chemical form of mercury in whale is found to closely resemble that found in fish. In the samples of skeletal muscle studied, no involvement of selenium in coordination of mercury is indicated in either whale or fish, with no significant inorganic HgSe or HgS type phases being detected. The selenium speciation in fish and whale shows that similar chemical types are present in each, but in significantly different proportions. Our results suggest that for equal amounts of Hg in skeletal muscle, the direct detrimental effects arising from the mercury content from consuming skeletal muscle from whale and fish should be similar if the effects of interactions with other components in the meat are not considered. PMID:21935544

  7. Cancer: beyond speciation.

    PubMed

    Vincent, Mark D

    2011-01-01

    A good account of the nature of cancer should provide not only a description of its consistent features, but also how they arise, how they are maintained, why conventional chemotherapy succeeds, and fails, and where to look for better targets. Cancer was once regarded as enigmatic and inexplicable; more recently, the "mutation theory," based on random alterations in a relatively small set of proto-oncogenes and tumor suppressor genes, has enjoyed widespread acceptance. The "mutation theory," however, is noticeable for its failure to explain the basis of differential chemosensitivity, for providing a paucity of targets, especially druggable ones, and for justifying the development of targeted therapies with, in general, disappointingly abbreviated clinical benefit. Furthermore, this theory has mistakenly predicted a widespread commonality of consistent genetic abnormalities across the range of cancers, whereas the opposite, that is, roiling macrogenomic instability, is generally the rule. In contrast, concerning what actually is consistent, that is, the suite of metabolic derangements common to virtually all, especially aggressive, cancers, the "Mutation Theory" has nothing to say. Other hypotheses merit serious consideration "aneuploidy theories" posit whole-genome instability and imbalance as causally responsible for the propagation of the tumor. Another approach, that is, "derepression atavism," suggests cancer results from the release of an ancient survival program, characterized by the emergence of remarkably primitive features such as unicellularity, fermentation, and immortality; existential goals are served by heuristic genomic instability coupled with host-to-tumor biomass interconversion, mediated by the Warburg effect, a major component of the program. Carcinogenesis is here seen as a process of de-speciation; however, genomic nonrestabilization raises issues as to where on the tree of life cancers belong, as a genuinely alternative modus vivendi

  8. Bacterial reduction of selenium in coal mine tailings pond sediment

    SciTech Connect

    Siddique, T.; Arocena, J.M.; Thring, R.W.; Zhang, Y.Q.

    2007-05-15

    Sediment from a storage facility for coal tailings solids was assessed for its capacity to reduce selenium (Se) by native bacterial community. One Se{sup 6+}-reducing bacterium Enterobacter hormaechei (Tar11) and four Se{sup 4+}-reducing bacteria, Klebsiella pneumoniae (Tar1), Pseudomonasfluorescens (Tar3), Stenotrophomonas maltophilia (Tar6), and Enterobacter amnigenus (Tar8) were isolated from the sediment. Enterobacter horinaechei removed 96% of the added Se{sup 6+} (0.92 mg L{sup -1} from the effluents when Se6+ was determined after 5 d of incubation. Analysis of the red precipitates showed that Se{sup 6+} reduction resulted in the formation of spherical particles ({lt}1.0 {mu} m) of Se 0 as observed under scanning electron microscope (SEM) and confirmed by EDAX. Selenium speciation was performed to examine the fate of the added Se{sup 6+} in the sediment with or without addition of Enterobacter hormaechei cells. More than 99% of the added Se{sup 6+} (about 2.5 mg L{sup -1}) was transformed in the nonsterilized sediment (without Enterobacter hormaechei cells) as well as in the sterilized (heat-killed) sediment (with Enterobacter hormaechei cells). The results of this study suggest that the lagoon sediments at the mine site harbor Se{sup 6+}- and Se{sup 4+} -reducing bacteria and may be important sinks for soluble Se (Se{sup 6+} and Se{sup 4+}). Enterobacter hormaechei isolated from metal-contaminated sediment may have potential application in removing Se from industrial effluents.

  9. Chemoselective Boronic Ester Synthesis by Controlled Speciation**

    PubMed Central

    Fyfe, James W B; Seath, Ciaran P; Watson, Allan J B

    2014-01-01

    Control of boronic acid solution speciation is presented as a new strategy for the chemoselective synthesis of boronic esters. Manipulation of the solution equilibria within a cross-coupling milieu enables the formal homologation of aryl and alkenyl boronic acid pinacol esters. The generation of a new, reactive boronic ester in the presence of an active palladium catalyst also facilitates streamlined iterative catalytic C=C bond formation and provides a method for the controlled oligomerization of sp2-hybridized boronic esters. PMID:25267096

  10. Plasma selenium and risk of dysglycemia in an elderly French population: results from the prospective Epidemiology of Vascular Ageing Study

    PubMed Central

    2010-01-01

    Background A preventive role of selenium on the risk of diabetes has been reported and ascribed to the "insulin-like" activity of selenium and the antioxidant properties of the selenoenzymes. By contrast, data from cross-sectional studies and clinical trials have suggested an adverse effect of high selenium status and selenium supplementation on type-2 diabetes risk. Given these controversial results, we investigated prospectively the relationship between baseline plasma selenium concentration and occurrence of dysglycemia (impaired fasting glucose or type 2 diabetes) in an elderly French cohort. Methods The Epidemiology of Vascular Ageing (EVA) study (n = 1389, 59-71 years) is a 9-year longitudinal study in which, fasting plasma glucose was measured at baseline, 2, 4 and 9 years. Analyses were performed on 1162 participants with complete data. Results At baseline plasma selenium mean levels were 1.08 (0.21) μmol/l in men and 1.10 (0.20) μmol/l in women. During the 9-year follow-up, 127 cases of dysglycemia occurred. A significant interaction was found between plasma selenium and sex. Risk of dysglycemia was significantly lower in men with plasma selenium in the highest tertile (T3:1.19-1.97) compared to those in the lowest tertile (T1:0.18-1.00) [HR = 0.48 (0.25-0.92)], but no significant relationship was observed in women. After controlling for socio-demographic factors, lifestyle factors, cardiovascular diseases, body mass index, hypertension and lipid profile, plasma selenium remained marginally significantly associated with occurrence of dysglycemia in men [T3 vs. T1, HR = 0.50 (0.24-1.04)] and unrelated in women. Conclusions This prospective study suggests a sex-specific protective effect of higher selenium status at baseline on later occurrence of dysglycemia. PMID:20298544

  11. Plasma selenium status in a group of Australian blood donors and fresh blood components.

    PubMed

    McDonald, Charles; Colebourne, Kathryn; Faddy, Helen M; Flower, Robert; Fraser, John F

    2013-10-01

    The purpose of this study was to assess plasma selenium levels in an Australian blood donor population and measure extra-cellular selenium levels in fresh manufactured blood components. Selenium levels were measured using graphite furnace atomic absorption spectrometry with Zeeman background correction. The mean plasma selenium level in healthy plasmapharesis donors was 85.6±0.5 μg/L and a regional difference was observed between donors in South East Queensland and Far North Queensland. Although participants had selenium levels within the normal range (55.3-110.5 μg/L), 88.5% had levels below 100 μg/L, a level that has been associated with sub-optimal activity of the antioxidant enzyme glutathione peroxidase (GPx). Extra-cellular selenium levels in clinical fresh frozen plasma (cFFP) and apheresis-derived platelets (APH Plt) were within the normal range. Packed red blood cells (PRBC) and pooled buffy coat-derived platelets (BC Plt) had levels at the lower limit of detection, which may have clinical implications to the massively transfused patient. PMID:23890534

  12. Low selenium environment and Vitamin E in human serum relative to the Kaschin-Beck's disease

    SciTech Connect

    Hou, S.; Zhu, Z.

    1982-04-30

    In China, endemic regions of Kaschin-Beck's disease, Keshan disease, and animal white muscle disease basically overlap, mainly the transitional area between the moist Southeast and the arid Northwest. Tests conducted by the authors reveal that the selenium content of major soils of the regions affected by the diseases is 0.088 to 0.360 ppM, that of the grains below 20 to 30 ppB. Of the inhabitants, 94 percent have serum selenium content below 0.031 ..mu..g/l and the selenium content of the hair of inhabitants is 100 to 200 ppB. From July 1979 to June 1980, the authors treated 41 cases of Kaschin-Beck's disease with sodium selenite-V/sub E/ and 36 of them recovered from the disease. Based upon these data, the authors believe that environmental selenium deficiency of these regions is perhaps the cause of the low level selenium nutrition of the inhabitants. The low level selenium nutrition in turn leads to a reduction of certain enzymic activity to cause the Kaschin-Beck's disease, as well as the Keshan disease and the animal white muscle disease.

  13. Field study of time-dependent selenium partitioning in soils using isotopically enriched stable selenite tracer.

    PubMed

    Di Tullo, Pamela; Pannier, Florence; Thiry, Yves; Le Hécho, Isabelle; Bueno, Maïté

    2016-08-15

    A better understanding of selenium fate in soils at both short and long time scales is mandatory to consolidate risk assessment models relevant for managing both contamination and soil fertilization issues. The purpose of this study was thus to investigate Se retention processes and their kinetics by monitoring time-dependent distribution/speciation changes of both ambient and freshly added Se, in the form of stable enriched selenite-77, over a 2-years field experiment. This study clearly illustrates the complex reactivity of selenium in soil considering three methodologically defined fractions (i.e. soluble, exchangeable, organic). Time-dependent redistribution of Se-77 within solid-phases having different reactivity could be described as a combination of chemical and diffusion controlled processes leading to its stronger retention. Experimental data and their kinetic modeling evidenced that transfer towards less labile bearing phases are controlled by slow processes limiting the overall sorption of Se in soils. These results were used to estimate time needed for (77)Se to reach the distribution of naturally present selenium which may extend up to several decades. Ambient Se speciation accounted for 60% to 100% of unidentified species as function of soil type whereas (77)Se(IV) remained the more abundant species after 2-years field experiment. Modeling Se in the long-term without taking account these slow sorption kinetics would thus result in underestimation of Se retention. When using models based on Kd distribution coefficient, they should be at least reliant on ambient Se which is supposed to be at equilibrium. PMID:27100008

  14. Surface functionalized selenium nanoparticles for biomedical applications.

    PubMed

    Chaudhary, Savita; Umar, Ahmad; Mehta, S K

    2014-10-01

    Selenium nanoparticles present an enhanced genetic actions and possess superior adsorptive capacity due to the interaction between the nanoparticles and NH, C=O, COO- and C-N groups of proteins. This review is focused on the biomedical applications of surafce funtionalized selenium nanoparticles. The engineering of exterior surface of the selenium nanoparticles has further emphasizing on the recent progresses in regulating monolayer structures for competent delivery of drugs and biomolecules. Crucial queries of transport, uptake, and clearance are discussed and illustrated through the prospects of selenium nanoparticles. The work presents an insight of how biomedical research can evolve with selenium nanoparticles and where we see the field is heading in the near future. PMID:25992427

  15. Selenium induces a multi-targeted cell death process in addition to ROS formation.

    PubMed

    Wallenberg, Marita; Misra, Sougat; Wasik, Agata M; Marzano, Cristina; Björnstedt, Mikael; Gandin, Valentina; Fernandes, Aristi P

    2014-04-01

    Selenium compounds inhibit neoplastic growth. Redox active selenium compounds are evolving as promising chemotherapeutic agents through tumour selectivity and multi-target response, which are of great benefit in preventing development of drug resistance. Generation of reactive oxygen species is implicated in selenium-mediated cytotoxic effects on cancer cells. Recent findings indicate that activation of diverse intracellular signalling leading to cell death depends on the chemical form of selenium applied and/or cell line investigated. In the present study, we aimed at deciphering different modes of cell death in a single cell line (HeLa) upon treatment with three redox active selenium compounds (selenite, selenodiglutathione and seleno-DL-cystine). Both selenite and selenodiglutathione exhibited equipotent toxicity (IC50 5 μM) in these cells with striking differences in toxicity mechanisms. Morphological and molecular alterations provided evidence of necroptosis-like cell death in selenite treatment, whereas selenodiglutathione induced apoptosis-like cell death. We demonstrate that selenodiglutathione efficiently glutathionylated free protein thiols, which might explain the early differences in cytotoxic effects induced by selenite and selenodiglutathione. In contrast, seleno-DL-cystine treatment at an IC50 concentration of 100 μM induced morphologically two distinct different types of cell death, one with apoptosis-like phenotype, while the other was reminiscent of paraptosis-like cell death, characterized by induction of unfolded protein response, ER-stress and occurrence of large cytoplasmic vacuoles. Collectively, the current results underline the diverse cytotoxic effects and variable potential of redox active selenium compounds on the survival of HeLa cells and thereby substantiate the potential of chemical species-specific usage of selenium in the treatment of cancers. PMID:24400844

  16. Mammary cancer prevention by regular garlic and selenium-enriched garlic.

    PubMed

    Ip, C; Lisk, D J; Stoewsand, G S

    1992-01-01

    The anticarcinogenic activities of regular (soil-grown) garlic and selenium-enriched garlic (cultivated in the greenhouse) were evaluated using the 7,12-dimethylbenz[a]anthracene-(DMBA) induced mammary tumor model in rats. In Experiment 1, milled regular garlic powder was added to the basal AIN-76A diet at 20 g/kg. The results from different schedules of supplementation suggested that a continuous treatment, which started before DMBA and persisted for the entire duration of the study, was most effective in tumor suppression. In Experiment 2, selected allyl group-containing sulfides that are normal constituents of garlic extract were given by gavage in three single doses immediately before DMBA. Several structurally related compounds were found to be protective during the initiation phase in the mammary cancer model. Although the present study was not designed specifically to elucidate the structure-activity relationship with respect to sulfur chain length or alkyl versus alkenyl substitution, our data showed that diallyl disulfide was more active than diallyl sulfide or allyl methyl sulfide. In Experiment 3, the anticarcinogenic activity of selenium-enriched garlic (containing 150 ppm Se dry weight from growth in a selenium-fertilized medium) was compared with that of regular garlic as well as selenite. Animals given the selenium-enriched garlic (final concentration 3 ppm Se in the diet) developed the fewest mammary tumors. Tissue selenium levels, however, were lower in these animals than in those fed the same amount of selenium from selenite. Our study demonstrated the feasibility of achieving cancer prevention with the use of a selenium-rich food system.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1437646

  17. 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. PMID:26781816

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

    PubMed Central

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

    2012-01-01

    Background/objectives Significant changes have been reported in dietary habits and food availability in Iceland that would be expected to compromise selenium intake and status, especially among young people. These include substantial decreases in the consumption of fish and milk, as well as the selenium content of imported wheat. The aim of this study was to assess selenium in the diet and whole blood of adolescent girls, as well as define the most important foods contributing to intake and blood concentrations of selenium. Design The subjects were 96 randomly selected girls, aged 16–20, who answered a validated food frequency questionnaire (FFQ) for dietary assessment. Selenium intake from each food group was calculated in µg/day. Blood samples were collected for measurement of whole blood selenium. Results Mean dietary selenium was 51±25 µg/day. Milk/dairy products, including cheese, contributed 36±14% of total dietary selenium; fish 18±12%; and bread/cereal products 13±6%. Mean whole blood selenium was 117±12 µg/l (range 90–208); nearly 90% of subjects were above the optimal level of 100 µg/l. Fish and bread/cereal products were the only foods significantly correlated with selenium in blood (r=0.32; P=0.002 and r=0.22; P=0.04, respectively) while no correlation was found with milk and dairy products in spite of their greater contribution to total selenium intake. Conclusion In this population of Icelandic adolescent girls, selenium intake and status seem acceptable. Judging from associations between intake and blood levels, fish and cereals may be the most important contributors to blood selenium. PMID:22952457

  19. Molybdenum Speciation and its Impact on Catalytic Activity during Methane Dehydroaromatization in Zeolite ZSM-5 as Revealed by Operando X-Ray Methods.

    PubMed

    Lezcano-González, Inés; Oord, Ramon; Rovezzi, Mauro; Glatzel, Pieter; Botchway, Stanley W; Weckhuysen, Bert M; Beale, Andrew M

    2016-04-18

    Combined high-resolution fluorescence detection X-ray absorption near-edge spectroscopy, X-ray diffraction, and X-ray emission spectroscopy have been employed under operando conditions to obtain detailed new insight into the nature of the Mo species on zeolite ZSM-5 during methane dehydroaromatization. The results show that isolated Mo-oxo species present after calcination are converted by CH4 into metastable MoCx Oy species, which are primarily responsible for C2 Hx /C3 Hx formation. Further carburization leads to MoC3 clusters, whose presence coincides with benzene formation. Both sintering of MoC3 and accumulation of large hydrocarbons on the external surface, evidenced by fluorescence-lifetime imaging microscopy, are principally responsible for the decrease in catalytic performance. These results show the importance of controlling Mo speciation to achieve the desired product formation, which has important implications for realizing the impact of CH4 as a source for platform chemicals. PMID:26990500

  20. LINKING WATERFOWL WITH CONTAMINANT SPECIATION IN RIPARIAN SOILS

    EPA Science Inventory

    This report summarizes the results of Mine Waste Technology Program (MWTP) Activity III, Project 38, Linking Waterfowl with Contaminant Speciation in Riparian Soils, implemented and funded by the U.S. Environmental Protection Agency (EPA) and jointly administered by EPA and the U...

  1. Selenium uptake by sulfur-accumulating bacteria

    NASA Astrophysics Data System (ADS)

    Nelson, Douglas C.; Casey, William H.; Sison, Jennette D.; Mack, E. Erin; Ahmad, Azeem; Pollack, Jeffrey S.

    1996-09-01

    Selenium is a trace metal in many rock-forming minerals but is a major environmental contaminant worldwide. Uptake of selenium by S-accumulating bacteria was examined in both pure cultures of Chromatium vinosum and in co-culture with Desulfovibrio desulfuricans. We used dual cultures including these bacteria to concentrate selenium into intracellular globules. The bacterium D. desulfuricans reduces sulfate [SO 42- (aq)] to sulfide [H 2S(aq)] and also reduces selenate [SeO 42- (aq)] to selenide [H 2Se (aq)]. Once reduced, sulfide is enzymatically oxidized and formed into intracellular globules by C. vinosum. We found that the selenium also forms an intercellular solid but the reaction is thermodynamically driven and proceeds by reducing S° (s) with H 2Se(aq). Relative to the initial molar ratio of selenate and sulfate in the medium, selenium is concentrated 4.5 to 32-fold in the globules. Because solid selenium is so much more stable than sulfur at growth conditions, other S-depositing bacteria, such as Beggiatoa and Chlorobium, should also concentrate selenium via this reaction, providing a strategy for eliminating contamination or for concentrating low natural levels into a usable form.

  2. PASSENGER CAR HYDROCARBON EMISSIONS SPECIATION

    EPA Science Inventory

    Emission factors for over 60 individual hydrocarbon compounds were determined for four passenger cars. The cars included a 1963 Chevrolet, a 1977 Mustang, and 1978 Monarch, and 1979 LTD II. The speciation data is reported for both tailpipe and evaporative emissions. The tailpipe ...

  3. A PERSONAL PARTICLE SPECIATION SAMPLER

    EPA Science Inventory

    Dr. Susanne Hering of Aerosol Dynamics Inc and her colleagues expect to design and validate a personal monitoring sampler for particles smaller than 2.5 µm (PM2.5) that is suitable for subsequent chemical speciation work. The investigators believe the result will be a...

  4. Studies of selenium and xenon in inductively coupled plasma mass spectrometry

    SciTech Connect

    Bricker, T.

    1994-07-27

    Since its development, inductively coupled plasma mass spectrometry (ICP-MS) has been a widely used analytical technique. ICP-MS offers low detection limits, easy determination of isotope ratios, and simple mass spectra from analyte elements. ICP-MS has been successfully employed for many applications including geological, environmental, biological, metallurgical, food, medical, and industrial. One specific application important to many areas of study involves elemental speciation by using ICP-MS as an element specific detector interfaced to liquid chromatography. Elemental speciation information is important and cannot be obtained by atomic spectrometric methods alone which measure only the total concentration of the element present. Part 1 of this study describes the speciation of selenium in human serum by size exclusion chromatography (SEC) and detection by ICP-MS. Although ICP-MS has been widely sued, room for improvement still exists. Difficulties in ICP-MS include noise in the background, matrix effects, clogging of the sampling orifice with deposited solids, and spectral interference caused by polyatomic ions. Previous work has shown that the addition of xenon into the central channel of the ICP decreases polyatomic ion levels. In Part 2 of this work, a fundamental study involving the measurement of the excitation temperature is carried out to further understand xenon`s role in the reduction of polyatomic ions. 155 refs.

  5. Revised reference values for selenium intake.

    PubMed

    Kipp, A P; Strohm, D; Brigelius-Flohé, R; Schomburg, L; Bechthold, A; Leschik-Bonnet, E; Heseker, H

    2015-10-01

    The German, Austrian and Swiss nutrition societies are the joint editors of the 'reference values for nutrient intake'. They have revised the reference values for the intake of selenium and published them in February 2015. The saturation of selenoprotein P (SePP) in plasma is used as a criterion for the derivation of reference values for selenium intake in adults. For persons from selenium-deficient regions (China) SePP saturation was achieved with a daily intake of 49μg of selenium. When using the reference body weights the D-A-CH reference values are based upon, the resulting estimated value for selenium intake is 70μg/day for men and 60μg/day for women. The estimated value for selenium intake for children and adolescents is extrapolated using the estimated value for adults in relation to body weight. For infants aged 0 to under 4 months the estimated value of 10μg/day was derived from the basis of selenium intake via breast milk. For infants aged 4 to under 12 months this estimated value was used and taking into account the differences regarding body weight an estimated value of 15μg/day was derived. For lactating women compared to non-lactating women a higher reference value of 75μg/day is indicated due to the release of selenium with breast milk. The additional selenium requirement for pregnant women is negligible, so that no increased reference value is indicated. PMID:26302929

  6. 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.

  7. Selenium content of game meat

    SciTech Connect

    Medeiros, L.C.; Belden, R.P. Univ. of Wyoming, Laramie )

    1991-03-11

    Selenium (Se) content of elk, deer, bison and beef were measured and compared. Samples were obtained from animals grazed on soil known to contain high, but variable amounts of Se. Beef were feedlot grazed and elk, deer, and bison were from captive or semi-captive herds. Selenium content was determined by graphite furnace after high pressure wet microwave digestion of samples. Deer and bison contained more Se than elk or beef. On a dry weight basis, deer contained more Se than bison. Game species contained more Se than beef. Within samples from male elk and deer and elk and bison of both genders, there were interactions between specie and muscle effects. Muscle and gender did not significantly influence Se content. The animals from which these samples were taken were supplemented with feeds grown on high Se containing soils, which was reflected in all values. Se values were twofold higher than those previously reported for meat. Those consuming large quantities of game from areas with high Se soil may need to monitor Se intake to avoid consuming excessive quantities.

  8. Randomised, double blind, placebo‐controlled trial of selenium supplementation in adult asthma

    PubMed Central

    Shaheen, Seif O; Newson, Roger B; Rayman, Margaret P; Wong, Angela P‐L; Tumilty, Michael K; Phillips, Joanna M; Potts, James F; Kelly, Frank J; White, Patrick T; Burney, Peter G J

    2007-01-01

    Background Epidemiological evidence from observational studies has suggested that blood levels and dietary intake of selenium of adults with asthma are lower than those of controls. The only previous trial of selenium supplementation in adults with asthma found no objective evidence of benefit but involved only 24 participants. Methods A randomised, double blind, placebo‐controlled trial of selenium supplementation was performed in adults with asthma in London, UK, the majority of whom (75%) reported inhaled steroid use at baseline. 197 participants were randomised to receive either a high‐selenium yeast preparation (100 µg daily, n = 99) or placebo (yeast only, n = 98) for 24 weeks. The primary outcome was asthma‐related quality of life (QoL) score. Secondary outcomes included lung function, asthma symptom scores, peak flow and bronchodilator usage. Linear regression was used to analyse the change in outcome between the two treatment arms by “intention to treat”. Results There was a 48% increase in plasma selenium between baseline and end of trial in the active treatment group but no change in the placebo group. While the QoL score improved more in the active treatment group than in the placebo group, the difference in change in score between the two groups was not significant (−0.05 (95% CI −0.19 to 0.09); p = 0.47). Selenium supplementation was not associated with any significant improvement in secondary outcomes compared with placebo. Conclusions Selenium supplementation had no clinical benefit in adults with asthma, the majority of whom were taking inhaled steroids. PMID:17234657

  9. Selenium accumulation and loss in mallard eggs

    SciTech Connect

    Heinz, G.H. )

    1993-04-01

    Five female mallards (Anas platyhynchos) that had just started egg laying were first fed a diet containing 15 ppm selenium in the form of selenomethionine for 20 d and then an untreated diet for 20 d. Selenium levels in eggs peaked (to about 13-20 ppm) in about two weeks on the treated diet and leveled off at a low level (< 5 ppm) after about 10 d back on the untreated diet. Selenium levels in egg whites responded faster than levels in yolks to the females' consumption of treated and untreated diets.

  10. Renal changes in selenium-exposed fish

    SciTech Connect

    Sorensen, E.M.; Harlan, C.W.; Bell, J.S.

    1982-06-01

    A group of green sunfish was collected from a selenium-rich lake and compared with a similar group collected from a control lake upstream in the same drainage system in east Texas. Since the level of selenium in kidneys of these fish was relatively high (averaging 11 ppm on a fresh weight basis), histopathological and ultrastructural data were collected. Kidneys from fish from the selenium-rich lake showed proliferative glomerulonephritis and hematuria as well as vacuolation and necrosis of cells of the convoluted tubules.

  11. Selenium isotope geochemistry: A new approach to characterizing the environmental chemistry of selenium. Final report

    SciTech Connect

    Volpe, A.M.; Esser, B.K.

    1997-02-05

    High levels of selenium in the environment will be a prominent water quality issue in the western United States for many years. Selenium accumulation is linked to increased rates of death and deformity in migratory birds, blind staggers in livestock, and selenosis in humans. In California, agricultural drain waters and oil refinery effluent contribute to high selenium content in the San Joaquin Valley and the San Francisco Bay. The importance of these industries to California`s economy precludes simple abatement, while the complexity of selenium cycling precludes simple remediation. The purpose of this project is to measure variations in the isotopic composition of selenium in water and soil samples caused by natural processes and to show, for the first time, the value of isotopic measurements in characterizing selenium pollution. The research seeks to identify sources of selenium pollution, determine processes in the selenium cycle, and support selenium remediation studies. The project required the successful integration of three components: (1) appropriate sampling a field setting showing Se enrichment and possibly isotopic fractionation, (2) analytical chemical methods for isolating and purifying the various species of Se in waters and sediment, and (3) mass spectroscopic instrumentation for high precision isotope abundance measurements.

  12. IFATS collection: Selenium induces improvement of stem cell behaviors in human adipose-tissue stromal cells via SAPK/JNK and stemness acting signals.

    PubMed

    Kim, Jeong Hwan; Lee, Mi Ran; Kim, Jee Hun; Jee, Min Ki; Kang, Soo Kyung

    2008-10-01

    In the present study, the potential of selenium to enhance stem cell behavior through improvement of human adipose tissue-derived stromal cells (ATSCs) and the associated molecular mechanism was evaluated. Selenium-induced improvement in stem cell behavior of human ATSCs caused expression of several genes, indicating downregulated mature cell marker proteins coupled with increased cell growth and telomerase activities after the overexpression of Rex1, Nanog, OCT4, SOX2, KLF4, and c-Myc. Also, selenium-treated ATSCs significantly downregulated p53 and p21 tumor suppressor gene products. Selenium induced active growth and growth enhanced by the activation of signal proteins in ATSCs via the inhibition of reactive oxygen species-mediated phospho-stress-activated protein kinase/c-Jun N-terminal protein kinase activation. The selenium-induced activation of extracellular regulated kinases 1/2 and Akt in ATSCs resulted in a subsequent induction of the expression of stemness transcription factors, particularly Rex1, Nanog, and Oct4, along with definitive demethylation on regulatory regions of Rex-1, Nanog, and Oct4. The results of our small interfering RNA knockdown experiment showed that Rex1 plays a major role in the proliferation of selenium-induced ATSCs. Selenium-treated ATSCs also exhibited more profound differentiation into mesodermal and neural lineages. We performed a direct comparison of gene expression profiles in control ATSCs and selenium-treated ATSCs and delineated specific members of important growth factor, signaling, cell adhesion, and transcription factor families. The observations of improved life span and multipotency of selenium-treated ATSCs clearly indicate that selenium-treated ATSCs represent an extraordinarily useful candidate cell source for tissue regeneration. Disclosure of potential conflicts of interest is found at the end of this article. PMID:18583539

  13. Encapsulation of selenium in chitosan nanoparticles improves selenium availability and protects cells from selenium-induced DNA damage response

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  14. Geochemical processes and the effects of natural organic solutes on the solubility of selenium in coal-mine backfill samples from the Powder River basin, Wyoming

    USGS Publications Warehouse

    See, R.B.; Reddy, K.J.; Vance, G.F.; Fadlelmawla, A.A.; Blaylock, M.J.

    1995-01-01

    Geochemical processes and the effects of natural organic solutes on the solubility of selenium in coal-mine backfill aquifers were investigated. Backfill and ground-water samples were collected at coal mines in the Powder River Basin, Wyoming. Backfill was generally dominated by aluminum (14,400 to 49,000 mg/kg (milligrams per kilogram)), iron (3,330 to 23,200 mg/kg), and potassium (7,950 to 18,000 mg/kg). Backfill saturated-paste selenium concentrations ranged from 1 to 156 mg/kg (microsiemens per kilogram). Ground-water total selenium concentrations ranged from 3 to 125 mg/L. Dissolved organic carbon in all ground-water samples was dominated by hydrophobic and hydrophilic acids (38 to 84 percent). Selenite sorption/desorption experiments were conducted using background solutions of distilled-deionized water, 0.1 molar calcium chloride, and isolated hydrophobic and hydrophilic acids. Selenite sorption was larger when 0.1 molar calcium chloride was used. The addition of hydrophilic acid decreased selenite sorption more than the addition of hydrophobic acids. Geochemical modelling was used to predict the solid phases controlling dissolved selenium concentrations and to evaluate the effects of dissolved organic carbon on selenium solubility. Results suggested that 55 to 90 percent of selenium in backfill precipitation/dissolution extracts was dominated by magnesium selenate ion pairs. Dissolved organic carbon had little effect on selenium speciation. A redox chamber was constructed to control Eh and pH in water and backfill-core sample suspensions. The response of selenite and selenate in water samples to redox conditions did not follow thermodynamic predictions. Reduction of selenate in water samples did not occur at any of the redox levels tested.

  15. Epigenetic effects of selenium and their implications for health

    PubMed Central

    Speckmann, Bodo; Grune, Tilman

    2015-01-01

    Alterations of epigenetic marks are linked to normal development and cellular differentiation as well as to the progression of common chronic diseases. The plasticity of these marks provides potential for disease therapies and prevention strategies. Macro- and micro-nutrients have been shown to modulate disease risk in part via effects on the epigenome. The essential micronutrient selenium affects human health outcomes, e.g., cancers, cardiovascular and autoimmune diseases, via selenoproteins and through a range of biologically active dietary selenocompounds and metabolism products thereof. This review provides an assessment of the current literature regarding epigenetic effects of dietary and synthetic selenocompounds, which include the modulation of marks and editors of epigenetic information and interference with one-carbon metabolism, which provides the methyl donor for DNA methylation. The relevance of a selenium-epigenome interaction for human health is discussed, and we also indicate where future studies will be helpful to gain a deeper understanding of epigenetic effects elicited by selenium. PMID:25647085

  16. The synthesis of elemental selenium particles by Synechococcus leopoliensis.

    PubMed

    Hnain, Antoine; Brooks, Jordan; Lefebvre, Daniel D

    2013-12-01

    Exposure of Synechococcus leopoliensis to selenite in the light resulted in orange-colored granules associated with the cells. No such particles were made in dark grown cells or when selenite was replaced by selenate. Light and scanning electron microscopy revealed that the particles formed inside the cells. Furthermore, these were easily extracted and shown to be composed of selenium as determined by energy-dispersive X-ray spectroscopy. During selenium particle synthesis there was a concurrent loss of organic pigments in the cyanobacteria. Cells also become heavier as they produced and accumulated particles which were on average 220 nm in diameter and generally spherical in shape. The decline in selenite concentration in the culture media can be accounted for by the formation of cellular elemental selenium (Se(0)) during particle formation, although synthesis of small amounts of other Se compounds cannot be entirely discounted. Photosynthetic activity is required for the formation of Se(0), implicating the involvement of thylakoids. It is possible that an intimate association between the nascent particles and the thylakoids occurred. However, Se(0) granule formation did not occur peripherally between the thylakoid and the cytoplasmic membranes, but inside the thylakoid bands towards the center of the cells. It then appears that the particles are mobilized to the periphery and expelled from the cells, causing irreparable damage to the cell walls. PMID:24146080

  17. The Role of Iodine and Selenium in Autoimmune Thyroiditis.

    PubMed

    Duntas, L H

    2015-09-01

    Iodine and selenium (Se) are both essential elements to thyroid hormone economy, while they represent key players in the development of autoimmune thyroiditis.Chronic high iodine intake has been associated in various studies with increased frequency of autoimmune thyroiditis. In susceptible individuals, iodine excess increases intra-thyroid infiltrating Th17 cells and inhibits T regulatory (TREG) cells development, while it triggers an abnormal expression of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) in thyrocytes, thus inducing apoptosis and parenchymal destruction. As was shown in a mouse model, high iodine supply leads to changes in the immunogenicity of the thyroglobulin molecule, upregulation of vascular intercellular adhesion molecule-1 (ICAM-1), and reactive oxygen species (ROS) generation in the thyrocytes. Serum Se levels were found decreased in Hashimoto thyroiditis and especially in Graves' disease as well as in thyroid-associated ophthalmopathy patients, the levels being related to the pathogenesis and outcome. Selenium is strongly involved, via the variable selenoproteins, in antioxidant, redox, and anti-inflammatory processes. Selenium enhances CD4+/CD25 FOXP3 and T regulatory cells activity while suppressing cytokine secretion, thus preventing apoptosis of the follicular cells and providing protection from thyroiditis. Selenium supplementation may be useful in autoimmune thyroid diseases, though, while usually well-tolerated, it should not be universally recommended, and it is also likely to be helpful for those with low Se status and autoimmunity. Broadly speaking, the achievement and maintenance of "selenostasis" as well as adequate urinary iodine excretion are mandatory to control disease, while, putatively, they may additionally be critical to preventing disease. PMID:26361258

  18. Differing views of the role of selenium in thioredoxin reductase

    PubMed Central

    Ruggles, Erik L.

    2010-01-01

    This review covers three different chemical explanations that could account for the requirement of selenium in the form of selenocysteine in the active site of mammalian thioredoxin reductase. These views are the following: (1) the traditional view of selenocysteine as a superior nucleophile relative to cysteine, (2) the superior leaving group ability of a selenol relative to a thiol due to its significantly lower pKa and, (3) the superior ability of selenium to accept electrons (electrophilicity) relative to sulfur. We term these chemical explanations as the “chemico-enzymatic” function of selenium in an enzyme. We formally define the chemico-enzymatic function of selenium as its specific chemical property that allows a selenoenzyme to catalyze its individual reaction. However we, and others, question whether selenocysteine is chemically necessary to catalyze an enzymatic reaction since cysteine-homologs of selenocysteine-containing enzymes catalyze their specific enzymatic reactions with high catalytic efficiency. There must be a unique chemical reason for the presence of selenocysteine in enzymes that explains the biological pressure on the genome to maintain the complex selenocysteine-insertion machinery. We term this biological pressure the “chemico-biological” function of selenocysteine. We discuss evidence that this chemico-biological function is the ability of selenoenzymes to resist inactivation by irreversible oxidation. The way in which selenocysteine confers resistance to oxidation could be due to the superior ability of the oxidized form of selenocysteine (Sec-SeO2−, seleninic acid) to be recycled back to its parent form (Sec-SeH, selenocysteine) in comparison to the same cycling of cysteine-sulfinic acid to cysteine (Cys-SO2− to Cys-SH). PMID:20397034

  19. Selenium bioaccessibility and bioavailability in Se-enriched food supplements.

    PubMed

    Thiry, Celine; Schneider, Yves-Jacques; Pussemier, Luc; De Temmerman, Ludwig; Ruttens, Ann

    2013-04-01

    Most European people have selenium (Se) intake inferior to recommended values that are considered necessary to ensure the beneficial action of antioxidant selenoproteins. People could therefore tend to have recourse to Se-enriched food supplements (FS) aiming to increase their Se body level. On the Belgian market, three main types of Se-rich FS are available: Se-enriched yeast, selenate-based FS, and selenite-based FS. In the present work, in vitro tests imitating gastrointestinal digestion and intestinal absorption were used to determine the bioaccessible and bioavailable fractions of Se present in one specimen of each category of FS. The aim of the study was to verify to which extent the difference in Se speciation could influence the efficiency of FS for enhancing the human Se status. Results indicated that differences exist in both bioaccessibility and bioavailability between the three types of FS, and that these differences could be related, at least partially, to the Se species profile. Overall bioavailability of the three FS was low (maximum 14 % of the original Se content). Among the three samples, the selenate-based FS produced the highest fraction of bioavailable Se, followed by Se-yeast, and finally by the selenite-based FS for which Se was almost not available at all. These results confirm the low availability of inorganic Se but were somewhat unexpected regarding the yeast-based FS since Se-rich yeasts are usually reported to contain an important fraction of available Se. PMID:23397356

  20. Serum selenium concentrations in rheumatoid arthritis.

    PubMed Central

    O'Dell, J R; Lemley-Gillespie, S; Palmer, W R; Weaver, A L; Moore, G F; Klassen, L W

    1991-01-01

    Selenium is a trace element and an essential part of the enzyme glutathione peroxidase, which protects cells from oxidative damage. Selenium has been shown to have antiproliferative, anti-inflammatory, antiviral, and immune altering effects. Serum selenium concentrations in 101 patients with seropositive rheumatoid arthritis were found to be significantly lower than those in 29 normal, healthy controls (mean (SD) 148 (42) v 160 (25) micrograms/l) and also lower than those in eight patients with fibrositis (148 (42) v 166 (25) micrograms/l). It is speculated that serum selenium concentrations may modulate the effect of viral or other infections in subjects with the appropriate genetic background and in this way enhance the development or progression of rheumatoid arthritis. PMID:2059080

  1. Biofortification and phytoremediation of selenium in China

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Biofortification is an agricultural process that increases the uptake and accumulation of specific nutrients, e.g. selenium (Se), in agricultural food products through plant breeding, genetic engineering, and manipulation of agronomic practices. The development and uses of biofortified agricultural ...

  2. Review of selenium and prostate cancer prevention.

    PubMed

    Yang, Lei; Pascal, Mouracade; Wu, Xiao-Hou

    2013-01-01

    Prostate cancer is the most common malignancy in men in the United States. Surgery or radiation are sometimes unsatisfactory treatments because of the complications such as incontinence or erectile dysfunction. Selenium was found to be effective to prevent prostate cancer in the Nutritional Prevention of Cancer Trial (NPC), which motivated two other clinical trials: the Selenium and Vitamin E Cancer Prevention Trial (SELECT) and a Phase III trial of selenium to prevent prostate cancer in men with high-grade prostatic intraepithelial neoplasia. However, these two trials failed to confirm the results of the NPC trial and indicated that the selenium may not be preventive of prostate cancer. In this article we review the three clinical trials and discuss some different points which might be potential factors underlying variation in results obtained. PMID:23725109

  3. Biosynthesis of selenium-modified tRNAs in Methanococcus vannielii

    SciTech Connect

    Politino, M.; Tsai, L.; Veres, Z.; Stadtman, T.C. )

    1990-08-01

    Selenium-containing nucleosides are natural components of several tRNA species in Methanococcus vannielii. In the present study, the incorporation of selenium from 75SeO3(2-) into these macromolecules was investigated in sonic extracts of M. vannielii. Nucleoside analysis of the 75Se-labeled tRNAs from these in vitro reaction mixtures demonstrated that the selenium was present in 75Se-labeled nucleosides identical to the two naturally occurring 2-selenouridines produced in vivo. Incorporation of selenium into these nucleosides was ATP-dependent and was maximal after 20 min. Addition of O-acetylserine enhanced the activity 2- to 3-fold, implicating a role for selenocysteine in the reaction. Added L-selenocysteine could function as a selenium donor, but the D isomer and DL-selenomethionine were inactive. RPC-5 chromatography of bulk tRNA isolated from M. vannielii grown on 75SeO3(2-) separated five major species of seleno-tRNAs. The amino acid-accepting activity of these tRNAs was investigated.

  4. Optimization of an Escherichia coli formate dehydrogenase assay for selenium compounds.

    PubMed Central

    Tschursin, E; Wolf, W R; Lacroix, D; Veillon, C; Patterson, K Y

    1994-01-01

    A microbiological assay to detect different chemical compounds of selenium for potential future use in the study of the distribution of these chemical forms in foods is being developed. This assay is based on the detection, by infrared analysis, of CO2 in a culture of Escherichia coli when the bacteria are grown in the presence of various selenium compounds. The CO2 production is the result of selenium-dependent formate dehydrogenase activity, which catalyzes oxidation of formic acid produced during glucose metabolism. Smooth response curves were generated over several orders of magnitude for selenocystine, selenite, and selenomethionine. The assay detects selenium concentrations (above background) as low as 1.5 nM for selenocystine and selenite and 4 nM for selenomethionine in minimal medium. Detection of selenomethionine was enhanced (to a sensitivity of 1.5 nM) by the addition of methionine to minimal medium and was enhanced even further (to a sensitivity of 0.8 nM) by the addition of a defined mixture of amino acids. Selenomethionine could be assayed in the presence of an amino acid concentration which is proportional to the amino acid/elemental selenium ratio found in a wheat gluten reference material (NIST SRM 8418). This implies that the assay can detect selenium compounds in a variety of foods at low concentrations, avoiding the background CO2 production caused by high concentrations of non-selenium-containing amino acids. The observation that methionine enhanced selenomethionine availability for formate dehydrogenase synthesis supports studies in animals demonstrating that methionine controls selenomethionine incorporation into selenoenzymes.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7811071

  5. Pharmaconutrition with selenium in critically ill patients: what do we know?

    PubMed

    Manzanares, William; Langlois, Pascal L; Heyland, Daren K

    2015-02-01

    Selenium is a component of selenoproteins with antioxidant, anti-inflammatory, and immunomodulatory properties. Systemic inflammatory response syndrome (SIRS), multiorgan dysfunction (MOD), and multiorgan failure (MOF) are associated with an early reduction in plasma selenium and glutathione peroxidase activity (GPx), and both parameters correlate inversely with the severity of illness and outcomes. Several randomized clinical trials (RCTs) evaluated selenium therapy as monotherapy or in antioxidant cocktails in intensive care unit (ICU) patient populations, and more recently several meta-analyses suggested benefits with selenium therapy in the most seriously ill patients. However, the largest RCT on pharmaconutrition with glutamine and antioxidants, the REducing Deaths due to Oxidative Stress (REDOXS) Study, was unable to find any improvement in clinical outcomes with antioxidants provided by the enteral and parenteral route and suggested harm in patients with renal dysfunction. Subsequently, the MetaPlus study demonstrated increased mortality in medical patients when provided extra glutamine and selenium enterally. The treatment effect of selenium may be dependent on the dose, the route of administration, and whether administered with other nutrients and the patient population studied. Currently, there are few small studies evaluating the pharmacokinetic profile of intravenous (IV) selenium in SIRS, and therefore more data are necessary, particularly in patients with MOD, including those with renal dysfunction. According to current knowledge, high-dose pentahydrate sodium selenite could be given as an IV bolus injection (1000-2000 µg), which causes transient pro-oxidant, cytotoxic, and anti-inflammatory effects, and then followed by a continuous infusion of 1000-1600 µg/d for up to 10-14 days. Nonetheless, the optimum dose and efficacy still remain controversial and need to be definitively established. PMID:25524883

  6. [Effect of selenium enriched diet on lipid peroxidation in patients with diabetes mellitus type 2].

    PubMed

    Skripchenko, N D; Sharafetdinov, Kh Kh; Plotnikova, O A; Meshcheriakova, V A; Mal'tsev, G Iu

    2003-01-01

    It was investigated the influence of a diet supplemented with selenium on the clinicometabolic parameters and the activity of lipid peroxidation in 43 patients with Type 2 diabetes mellitus. It was indicated that under the influence of dietotherapy besides the decrease of glucose levels in capillary and venous blood, improvement of parameters of lipid metabolism, a reduction of malondialdehyde level and tendency to increase of glutathione peroxidase activity were observed. The results of investigations testify about sufficiently expressed efficacy of a diet supplemented with selenium in correction of oxidative stress and clinicometabolic parameters in this contingent of patients. PMID:12664692

  7. [Selenium. Its physiologic and clinical importance].

    PubMed

    da Silva, A P

    1993-07-01

    Since its discovery in 1817, Selenium has had great biological importance as a key element of cellular protection and in its absence of pathological symptoms. In this revised work, historical aspects of selenium are considered, its characteristics, properties and source as well as its nutritional value, metabolism, physiopathological and biochemical function in humans and finally its future therapeutical application in humans and animals considering some of the traditional ways of treatment. PMID:8379356

  8. Production of selenium-72 and arsenic-72

    DOEpatents

    Phillips, Dennis R.

    1995-01-01

    Methods and apparatus for producing selenium-72, separating it from its daughter isotope arsenic-72, and generating multiple portions of a solution containing arsenic-72 from a reusable parent substance comprised of selenium-72. The invention provides apparatus which can be located at a site where arsenic-72 is used, for purposes such as PET imaging, to produce arsenic-72 as needed, since the half-life of arsenic-72 is very short.

  9. Production of selenium-72 and arsenic-72

    DOEpatents

    Phillips, Dennis R.

    1994-01-01

    Methods and apparatus for producing selenium-72, separating it from its daughter isotope arsenic-72, and generating multiple portions of a solution containing arsenic-72 from a reusable parent substance comprised of selenium-72. The invention provides apparatus which can be located at a site where arsenic-72 is used, for purposes such as PET imaging, to produce arsenic-72 as needed, since the half-life of arsenic-72 is very short.

  10. Production of selenium-72 and arsenic-72

    DOEpatents

    Phillips, D.R.

    1994-12-06

    Methods and apparatus are described for producing selenium-72, separating it from its daughter isotope arsenic-72, and generating multiple portions of a solution containing arsenic-72 from a reusable parent substance comprised of selenium-72. The invention provides apparatus which can be located at a site where arsenic-72 is used, for purposes such as PET imaging, to produce arsenic-72 as needed, since the half-life of arsenic-72 is very short. 2 figures.

  11. Effect of dietary vitamin E or selenium on prostaglandin dehydrogenase in hyperoxic rat lung

    NASA Technical Reports Server (NTRS)

    North, L. N.; Mathias, M. M.; Schatte, C. L.

    1984-01-01

    Weanling male rats were fed semipurified diets supplemented with 0, 60, or 600 IU/kg vitamin E or 0, 100, or 1000 ppb selenium. One group was injected daily with vitamin E at a rate equivalent to consumption of 60 IU/kg. Animals from all groups were sacrificed after exposure to normobaric oxygen or air for 48 h. Lung tissue was analyzed for the combined activity of prostaglandin dehydrogenase and reductase. Using the decline in enzyme activity as an indicator of susceptibility to oxygen poisoning, protection against hyperoxia was directly related to the level of vitamin E supplementation. Selenium supplemented at 100 ppb provided significant protection when compared to 0 ppb or 1000 ppb. The latter dose may have been marginally toxic. Thus dietary supplementation of vitamin E and selenium may influence the relative susceptibility of an animal to pulmonary oxygen poisoning.

  12. Selenium in Gluten-free Products.

    PubMed

    Rybicka, Iga; Krawczyk, Magdalena; Stanisz, Ewa; Gliszczyńska-Świgło, Anna

    2015-06-01

    The nutritional value of gluten-free products is the subject of interest for food technologists and nutritionists, as the only effective treatment for celiac disease is a lifelong gluten-free diet. As selenium deficiencies in celiac disease are observed, the aim of the study was to determine the selenium content in 27 grain gluten-free products available on the European Union (EU) market. Moreover, selenium content in products based on popular gluten-free cereals like corn, rice, and buckwheat and in relatively new or less popular products based on oat, amaranth, teff, and quinoa was compared. Selenium content in the tested products ranged from 0.9 to 24.5 μg/100 g. The average content of selenium in products based on popular gluten-free cereals was 2.8 μg/100 g and in products based on oat, amaranth, teff, and quinoa was 10.8 μg/100 g. It indicates that products based on less popular grains, especially on oat, should be more frequently chosen as a source of selenium by people on gluten-free diet than traditionally consumed gluten-free grains. PMID:25690718

  13. Anticipated soil selenium concentrations at Kesterson Reservoir

    SciTech Connect

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

    1992-10-01

    Temporal trends from soil monitoring data collected at Kesterson Reservoir have been reviewed to shed light on anticipated concentrations of total and water-extractable selenium in surface and subsurface soils. Based on these data, a mass balance model for selenium has been developed and employed to evaluate the rate of leaching, remobilization and volatilization that has occurred since the Reservoir was dried out in 1987. Results from a series of calibration runs were then extrapolated 25 years in the future to forecast the evolution and redistribution of selenium within the soil profile. Projected water-extractable selenium concentrations within the 0.15 to 1 m depth interval were then used to drive a food-chain based risk-assessment model described in a separate report (CH2M Hill, 1992). Inventories of water-extractable selenium in the root zone increased in 4 of the 5 scenarios investigated. However, predicted values for the average concentration of water-extractable selenium in the root zone fall within the range of values observed at Kesterson today. Consequences of these projected increases on wildlife residing in and around Kesterson are addressed in CH2M Hill (1992).

  14. MODELING MONOMETHYLMERCURY AND TRIBUTYLTIN SPECIATION WITH EPA'S GEOCHEMICAL SPECIATION MODEL MINTEQA2

    EPA Science Inventory

    Given the complexity of the various, simultaneous (and competing) equilibrium reactions governing the speciation of ionic species in aquatic systems, EPA has developed and distributed the geochemical speciation model MINTEQA2 (Brown and Allison, 1987, Allison et al., 1991; Hydrog...

  15. Thin film solar cells by selenization sulfurization using diethyl selenium as a selenium precursor

    DOEpatents

    Dhere, Neelkanth G.; Kadam, Ankur A.

    2009-12-15

    A method of forming a CIGSS absorber layer includes the steps of providing a metal precursor, and selenizing the metal precursor using diethyl selenium to form a selenized metal precursor layer (CIGSS absorber layer). A high efficiency solar cell includes a CIGSS absorber layer formed by a process including selenizing a metal precursor using diethyl selenium to form the CIGSS absorber layer.

  16. 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

  17. Arsenic Speciation of Terrestrial Invertebrates

    SciTech Connect

    Moriarty, M.M.; Koch, I.; Gordon, R.A.; Reimer, K.J. ); )

    2009-07-01

    The distribution and chemical form (speciation) of arsenic in terrestrial food chains determines both the amount of arsenic available to higher organisms, and the toxicity of this metalloid in affected ecosystems. Invertebrates are part of complex terrestrial food webs. This paper provides arsenic concentrations and arsenic speciation profiles for eight orders of terrestrial invertebrates collected at three historical gold mine sites and one background site in Nova Scotia, Canada. Total arsenic concentrations, determined by inductively coupled plasma mass spectrometry (ICP-MS), were dependent upon the classification of invertebrate. Arsenic species were determined by high-performance liquid chromatography (HPLC) ICP-MS and X-ray absorption spectroscopy (XAS). Invertebrates were found by HPLC ICP-MS to contain predominantly arsenite and arsenate in methanol/water extracts, while XAS revealed that most arsenic is bound to sulfur in vivo. Examination of the spatial distribution of arsenic within an ant tissue highlighted the differences between exogenous and endogenous arsenic, as well as the extent to which arsenic is transformed upon ingestion. Similar arsenic speciation patterns for invertebrate groups were observed across sites. Trace amounts of arsenobetaine and arsenocholine were identified in slugs, ants, and spiders.

  18. Selenium biotransformations into proteinaceous forms by foodweb organisms of selenium-laden drainage waters in California

    USGS Publications Warehouse

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

    2002-01-01

    Selenium contamination represents one of the few clear cases where environmental pollution has led to devastation of wildlife populations, most notably in agricultural drainage evaporation and power plant coal-fly ash receiving ponds. Complex biogeochemistry, in particular extensive biotransformations and foodchain transfer, governs Se ecotoxicology and toxicology, for which the mechanism(s) are still elusive. However, total waterborne Se concentration has been widely used as a criterion for regulating and mitigating Se risk in aquatic ecosystems, which does not account for Se biogeochemistry and its site-dependence. There is a need for more reliable indicator(s) that encompass Se ecotoxicity and/or toxicity. Selenomethionine warrants special attention since it simulates Se toxicosis of wildlife in laboratory feeding studies. While low in free selenomethionine, microphytes isolated from Se-laden agricultural evaporation ponds were abundant in proteinaceous selenomethionine. This prompted a more extensive survey of Se speciation in foodchain organisms including microphytes, macroinvertebrates, fish, and bird embryos residing mainly in the agricultural drainage systems of the San Joaquin Valley, California. Total Se in biomass, water-soluble fractions, and protein-rich fractions were measured along with GC-MS analysis of proteinaceous selenomethionine. In all foodchain organisms, water-soluble Se constituted the major fraction of total biomass Se, while proteinaceous Se was a substantial, if not dominant, fraction of the water-soluble Se. In turn, proteinaceous selenomethionine comprised an important fraction of proteinaceous Se. In terms of total biomass Se, an average 1400-fold of Se biomagnification from water to microphytes was observed while subsequent transfer from microphytes to macroinvertebrates exhibited an average of only 1.9-fold. The latter transfer was more consistent and greater in extent for proteinaceous Se and proteinaceous selenomethionine, which

  19. Dietary Selenium (Se) and Copper (Cu) Affect the Activity and Expression of the Hepatic Selenoprotein Methionine Sulfoxide Reductase B (MrsB) in Rats

    Technology Transfer Automated Retrieval System (TEKTRAN)

    As reported by Jenkinson et al. (J Nutr 1982) and Prohaska et al. (J Nutr Biochem 1992) Cu deficiency (CuD) decreases the activity and mRNA expression of the selenoprotein GPx. Because both Se and Cu are important in oxidative defense, we wanted to determine the effect of a combined deficiency on th...

  20. Daily Rhythm of Mutualistic Pollinator Activity and Scent Emission in Ficus septica: Ecological Differentiation between Co-Occurring Pollinators and Potential Consequences for Chemical Communication and Facilitation of Host Speciation

    PubMed Central

    Conchou, Lucie; Cabioch, Léa; Rodriguez, Lillian J. V.; Kjellberg, Finn

    2014-01-01

    The mutualistic interaction between Ficus and their pollinating agaonid wasps constitutes an extreme example of plant-insect co-diversification. Most Ficus species are locally associated with a single specific agaonid wasp species. Specificity is ensured by each fig species emitting a distinctive attractive scent. However, cases of widespread coexistence of two agaonid wasp species on the same Ficus species are documented. Here we document the coexistence of two agaonid wasp species in Ficus septica: one yellow-colored and one black-colored. Our results suggest that their coexistence is facilitated by divergent ecological traits. The black species is longer-lived (a few more hours) and is hence active until later in the afternoon. Some traits of the yellow species must compensate for this advantage for their coexistence to be stable. In addition, we show that the composition of the scent emitted by receptive figs changes between sunrise and noon. The two species may therefore be exposed to somewhat different ranges of receptive fig scent composition and may consequently diverge in the way they perceive and/or respond to scents. Whether such situations may lead to host plant speciation is an open question. PMID:25105796

  1. A Comprehensive Analysis of Selenium-Binding Proteins in the Brain Using Its Reactive Metabolite.

    PubMed

    Yoshida, Sakura; Hori, Eriko; Ura, Sakiko; Haratake, Mamoru; Fuchigami, Takeshi; Nakayama, Morio

    2016-01-01

    The intracellular metabolism of selenium in the brain currently remains unknown, although the antioxidant activity of this element is widely acknowledged to be important in maintaining brain functions. In this study, a comprehensive method for identifying the selenium-binding proteins using PenSSeSPen as a model of the selenium metabolite, selenotrisulfide (RSSeSR, STS), was applied to a complex cell lysate generated from the rat brain. Most of the selenium from L-penicillamine selenotrisulfide (PenSSeSPen) was captured by the cytosolic protein thiols in the form of STS through the thiol-exchange reaction (R-SH+PenSSeSPen→R-SSeSPen+PenSH). The cytosolic protein species, which reacted with the PenSSeSPen mainly had a molecular mass of less than 20 kDa. A thiol-containing protein at m/z 15155 in the brain cell lysate was identified as the cystatin-12 precursor (CST12) from a rat protein database search and a tryptic fragmentation experiment. CST12 belongs to the cysteine proteinase inhibitors of the cystatin superfamily that are of interest in mechanisms regulating the protein turnover and polypeptide production in the central nervous system and other tissues. Consequently, CST12 is suggested to be one of the cytosolic proteins responsible for the selenium metabolism in the brain. PMID:26726744

  2. Evidence that diabetes mellitus favors impaired metabolism of zinc, copper, and selenium in chronic pancreatitis.

    PubMed

    Quilliot, D; Dousset, B; Guerci, B; Dubois, F; Drouin, P; Ziegler, O

    2001-04-01

    Diabetes mellitus, a common complication of chronic pancreatitis, can disturb the metabolism of zinc, copper, and selenium. We analyzed the effects of hyperglycemia, malabsorption, and dietary intake on these factors in 35 men with alcohol-induced chronic pancreatitis complicated by insulin-treated diabetes mellitus (CP-D), 12 men with chronic pancreatitis but no diabetes (nondiabetic CP), 25 men with type 1 diabetes mellitus (type 1 DM), and 20 control subjects. Diabetes due to chronic pancreatitis was associated with decreased plasma zinc and selenium concentrations and with increased urinary copper excretion. Of the chronic pancreatitis patients, 17% had low plasma zinc, and 41% of them had low plasma selenium. None of the type 1 diabetic patients had low plasma concentrations of zinc, but 12% of them had a low selenium concentration. Hyperglycemia, as assessed by fasting plasma glucose and by plasma HbAlc, was responsible for the increased zinc excretion and the decreased superoxide dismutase activity. The perturbations of the copper, selenium, and zinc metabolism were particularly pronounced in subjects with chronic pancreatitis plus diabetes mellitus. We have yet to determine whether the differences in trace-element status contribute to the clinical expression of the disease. PMID:11291933

  3. Comparative study of DL-selenomethionine vs sodium selenite and seleno-yeast on antioxidant activity and selenium status in laying hens.

    PubMed

    Jing, C L; Dong, X F; Wang, Z M; Liu, S; Tong, J M

    2015-05-01

    The aim of this study was to compare the effect of DL-selenomethionine (SM) with 2 routinely used Se sources, sodium selenite (SS) and seleno-yeast (SY), on relative bioavailability based on antioxidant activity and tissue Se content. Six hundred thirty 131-day-old brown laying hens were randomly assigned to 7 treatments for 168 d (24 wks) with 6 replicates of 15 hens per replicate. The SS and SY animals were supplemented a cornmeal and soybean diet that supplied a total Se 0.3 mg/kg whereas SM was added at 4 different levels to the total Se at 0.1, 0.3, 0.5 and 0.7 mg/kg. All hens fed the Se-supplemented diet showed higher glutathione peroxidase (GSH-Px) activity (P < 0.01), higher superoxide dismutase (SOD) activity (P < 0.05), lower malondialdehyde (MDA) content (P < 0.05) in plasma, and greater Se contents in egg yolks, albumen, leg muscle, breast muscle, liver, and plasma compared with those fed the control diet (P < 0.01). The organic sources (SY and SM) exhibited a greater ability to increase the GSH-Px activity (P < 0.01) and Se content in albumen (P < 0.01), leg, and breast muscles (P = 0.0099 and P = 0.0014, respectively) than the SS that was added at 0.3 mg Se/kg. The higher SM added levels increased the GSH-Px activity until the dose of 0.5mg Se/kg (P < 0.01).The greater Se concentrations in albumen, muscle and liver appeared in the higher SM-added level, as well as above the dose of 0.1 mg Se/kg (P < 0.01). In addition, hens fed the diet with SM accumulated more Se in albumen, leg, and breast muscle than those fed diets with SY (P < 0.05). These results confirmed the higher ability of organic Se sources to increase the antioxidant activity and Se deposition in egg albumen, leg, and breast muscles compared with SS, and demonstrated a significantly better efficiency of SM compared with SY for albumen and muscle Se enrichment. PMID:25717085

  4. Assessment of co-contaminant effects on uranium and thorium speciation in freshwater using geochemical modelling.

    PubMed

    Lofts, Stephen; Fevrier, Laureline; Horemans, Nele; Gilbin, Rodolphe; Bruggeman, Christophe; Vandenhove, Hildegarde

    2015-11-01

    Speciation modelling of uranium (as uranyl) and thorium, in four freshwaters impacted by mining activities, was used to evaluate (i) the influence of the co-contaminants present on the predicted speciation, and (ii) the influence of using nine different model/database combinations on the predictions. Generally, co-contaminants were found to have no significant effects on speciation, with the exception of Fe(III) in one system, where formation of hydrous ferric oxide and adsorption of uranyl to its surface impacted the predicted speciation. Model and database choice on the other hand clearly influenced speciation prediction. Complexes with dissolved organic matter, which could be simulated by three of the nine model/database combinations, were predicted to be important in a slightly acidic, soft water. Model prediction of uranyl and thorium speciation needs to take account of database comprehensiveness and cohesiveness, including the capability of the model and database to simulate interactions with dissolved organic matter. Measurement of speciation in natural waters is needed to provide data that may be used to assess and improve model capabilities and to better constrain the type of predictive modelling work presented here. PMID:26225834

  5. Selenium-enriched Agaricus bisporus increases expression and activity of glutathione peroxidase-1 and expression of glutathione peroxidase-2 in rat colon.

    PubMed

    Maseko, Tebo; Howell, Kate; Dunshea, Frank R; Ng, Ken

    2014-03-01

    The effect of dietary supplementation with Se-enriched Agaricus bisporus on cytosolic gluthathione peroxidase-1 (GPx-1), gastrointestinal specific glutathione peroxidase-2 (GPx-2), thioredoxin reductase-1 (TrxR-1) and selenoprotein P (SeP) mRNA expression and GPx-1 enzyme activity in rat colon was examined. Rats were fed for 5weeks with control diet (0.15μg Se/g feed) or Se-enriched diet fortified with selenised mushroom (1μg Se/g feed). The mRNA expression levels were found to be significantly (P<0.01) up-regulated by 1.65-fold and 2.3-fold for GPx-1 and GPx-2, respectively, but were not significantly different for TrxR-1 and SeP between the 2 diet treatments. The up-regulation of GPx-1 mRNA expression was consistent with GPX-1 activity level, which was significantly (P<0.05) increased by 1.77-fold in rats fed with the Se-enriched diet compared to the control diet. The results showed that selenised A. bisporus can positively increase GPx-1 and GPx-2 gene expression and GPx-1 enzyme activity in rat colon. PMID:24176350

  6. Electrochemical behavior of chemically synthesized selenium thin film.

    PubMed

    Patil, A M; Kumbhar, V S; Chodankar, N R; Lokhande, A C; Lokhande, C D

    2016-05-01

    The facile and low cost simple chemical bath deposition (CBD) method is employed to synthesize red colored selenium thin films. These selenium films are characterized for structural, morphological, topographical and wettability studies. The X-ray diffraction (XRD) pattern showed the crystalline nature of selenium thin film with hexagonal crystal structure. The scanning electron microscopy (SEM) study displays selenium nanoparticles ranging from 20 to 475nm. A specific surface area of 30.5m(2)g(-1) is observed for selenium nanoparticles. The selenium nanoparticles hold mesopores in the range of 1.39nm, taking benefits of the good physicochemical stability and excellent porosity. Subsequently, the electrochemical properties of selenium thin films are deliberated by cyclic voltammetry (CV), galvanostatic charge-discharge and electrochemical impedance spectroscopy (EIS) techniques. The selenium thin film shows specific capacitance (Cs) of 21.98Fg(-1) with 91% electrochemical stability. PMID:26896773

  7. Geochemistry of selenium in a coastal salt marsh

    SciTech Connect

    Velinsky, D.J.; Cutter, G.A. )

    1991-01-01

    The cycling of sedimentary selenium was examined over a one-year period in the Great Marsh, Delaware (USA). While total selenium and elemental selenium decrease with depth in the sediments at similar rates, Se(IV + VI) exhibits pronounced seasonality related to the redox conditions of the marsh. Porewater selenium reflects the diagenetic cycling of Se(IV + VI) in the sediments and suggests that a partial remobilization of sedimentary selenium occurs when the upper sediments become oxidizing. Diagenetic and mass-balance models indicate that the major sources of selenium to the marsh are creek waters and atmospheric deposition, while total selenium may be removed from the sediments via the flux of volatile selenium compounds.

  8. Acute selenium toxicosis in polo ponies.

    PubMed

    Desta, Belainesh; Maldonado, Gizela; Reid, Herman; Puschner, Birgit; Maxwell, James; Agasan, Alice; Humphreys, Leigh; Holt, Thomas

    2011-05-01

    Just prior to an international polo event, 21 horses from one team exhibited clinical signs of central nervous system disturbance, hyperexcitability, sweating, ataxia, tachycardia, dyspnea, pyrexia, and rapid death. The suspected cause of this peracute onset of illness and death included intentional contamination of feed or iatrogenic administration of performance-enhancing drugs resulting in a severe adverse reaction. Six horses were submitted to the Bronson Animal Disease Diagnostic Laboratory for necropsy and toxicological examination. The clinical signs and sudden death, the similarity to earlier work by the lead author of selenium toxicosis in calves, as well as published reports, prompted investigators to focus on selenium testing. Sixty-four hours following receipt, the laboratory detected toxic selenium concentrations in the tissues of these animals. Following further investigation of the case by regulatory officials, it was determined that all affected horses had received an intravenous injection of a compounded "vitamin/mineral" supplement just prior to the onset of signs. The compounded supplement contained toxic levels of selenium. The present report illustrates the in-depth laboratory investigation of the cause of acute death in 6 polo ponies due to selenium toxicosis. In addition to solving this high profile case, the toxic levels of selenium found in livers (6.13 ± 0.31 mg/kg wet weight), kidneys (6.25 ± 0.3 mg/kg wet weight), and sera (1.50 ± 0.11 µg/ml) of these affected animals may provide important diagnostic criteria for future interpretations of selenium concentrations in tissues of horses. PMID:21908304

  9. Polonium-210 and selenium in tissues and tissue extracts of the mussel Mytilus galloprovincialis (Gulf of Trieste).

    PubMed

    Kristan, Urška; Planinšek, Petra; Benedik, Ljudmila; Falnoga, Ingrid; Stibilj, Vekoslava

    2015-01-01

    Marine organisms such as mussels and fish take up polonium (Po) and selenium (Se), and distribute them into different cellular components and compartments. Due to its high radiotoxicity and possible biomagnification across the marine food chain Po-210 is potentially hazardous, while selenium is an essential trace element for humans and animals. The aim of this study was to investigate and compare the presence and extractability of the elements in the mussels Mytilus galloprovincialis collected in the Gulf of Trieste. The levels of Po-210 in the samples ranged from 220 to 400 Bq kg(-1) and of Se from 2.6 to 8.2 mg kg(-1), both on a dry matter basis. Using various extraction types and conditions in water, buffer or enzymatic media, the best extractability was obtained with enzymatic extraction (Protease XIV, 1h shaking at 40 °C) and the worst by water extraction (24 h shaking at 37 °C). 90% of Po-210 and 70% of Se was extractable in the first case versus less than 10% of Po-210 and less than 40% of Se in the second. Such evident differences in extractability between the investigated elements point to different metabolic pathways of the two elements. In enzymatic extracts Se speciation revealed three Se compounds (SeCys2, SeMet, one undefined), while Po-210 levels were too low to allow any conclusions about speciation. PMID:25016556

  10. Use of stable isotopes of selenium in human metabolic studies: development of analytical methodology

    SciTech Connect

    Janghorbani, M.; Ting, B.T.; Young, V.R.

    1981-12-01

    Use of stable isotopes of selenium in relation to enrichment of diets for studies of selenium absorption and metabolism in human subjects is discussed. A method based on radiochemical neutron activation analysis is described which allows accurate measurement of stable isotopes 74Se, 76Se, and 80Se in matrices (feces, plasma, red blood cells, and urine) of interest in metabolic studies. We show that these isotopes can routinely be measured with analytical precision and accuracy of 10% in samples of available size. This precision and accuracy is satisfactory for conduct of many nutritional experiments concerned with gastrointestinal absorption, plasma and red cell selenium turnover, and urinary excretion of the element, using an oral dose of 74Se. Original, experimental data are presented to illustrate the degree of enrichment of 74Se in feces, plasma, and urine after a single oral ingestion of 50 micrograms of the isotope with a breakfast meal in healthy young men.

  11. 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.

  12. Mercury speciation in the Adriatic Sea.

    PubMed

    Kotnik, Jože; Horvat, Milena; Ogrinc, Nives; Fajon, Vesna; Žagar, Dušan; Cossa, Daniel; Sprovieri, Francesca; Pirrone, Nicola

    2015-07-15

    Mercury and its speciation were studied in surface and deep waters of the Adriatic Sea. Several mercury species (i.e. DGM – dissolved gaseous Hg, RHg – reactive Hg, THg – total Hg, MeHg – monomethyl Hg and DMeHg – dimethylmercury) together with other water parameters were measured in coastal and open sea deep water profiles. THg concentrations in the water column, as well as in sediments and pore waters, were the highest in the northern, most polluted part of the Adriatic Sea as the consequence of Hg mining in Idrija and the heavy industry of northern Italy. Certain profiles in the South Adriatic Pit exhibit an increase of DGM just over the bottom due to its diffusion from sediment as a consequence of microbial and/or tectonic activity. Furthermore, a Hg mass balance for the Adriatic Sea was calculated based on measurements and literature data. PMID:26013591

  13. Selenium and diabetes - evidence from animal studies

    PubMed Central

    Zhou, Jun; Huang, Kaixun; Lei, Xin Gen

    2013-01-01

    Whereas selenium was found to act as an insulin-mimic and to be anti-diabetic in earlier studies, recent animal experiments and human trials have shown unexpected risk of prolonged high Se intake in potentiating insulin resistance and type 2 diabetes. Elevating dietary Se intakes (0.4 to 3.0 mg/kg of diet) above the nutrient requirements, similar to overproduction of selenoproteins, led to insulin resistance and(or) diabetes-like phenotypes in mice, rats, and pigs. Although its diabetogenic mechanism remains unclear, the high Se intake elevated activity or production of selenoproteins including GPx1, MsrB1, SelS, and SelP. This up-regulation diminished intracellular reactive oxygen species (ROS) and then dys-regulated key regulators of β cells and insulin synthesis and secretion, leading to chronic hyperinsulinaemia. Over-scavenging intracellular H2O2 also attenuated oxidative inhibition of protein tyrosine phosphatases and suppressed insulin signaling. High Se intake might affect expression and(or) function of key regulators for glycolysis, gluconeogenesis, and lipogenesis. Future research is needed to find out if certain forms of Se metabolites in addition to selenoproteins and if mechanisms other than intracellular redox control mediate the diabetogenic effect of high Se intakes. Furthermore, a potential interactive role of high Se intakes in the interphase of carcinogenesis and diabetogenesis should be explored to make the optimal use of Se in human nutrition and health. PMID:23867154

  14. Study of selenocompounds from selenium-enriched culture of edible sprouts.

    PubMed

    Funes-Collado, Virginia; Morell-Garcia, Albert; Rubio, Roser; López-Sánchez, José Fermín

    2013-12-15

    Selenium is recognised as an essential micronutrient for humans and animals. One of the main sources of selenocompounds in the human diet is vegetables. Therefore, this study deals with the Se species present in different edible sprouts grown in Se-enriched media. We grew alfalfa, lentil and soy in a hydroponic system amended with soluble salts, containing the same proportion of Se, in the form of Se(VI) and Se(IV). Total Se in the sprouts was determined by acidic digestion in a microwave system and by ICP/MS. Se speciation was carried out by enzymatic extraction (Protease XIV) and measured by LC-ICP/MS. The study shows that the Se content of plants depends on the content in the growth culture, and that part of the inorganic Se was biotransformed mainly into SeMet. These results contribute to our understanding of the uptake of inorganic Se and its biotransformation by edible plants. PMID:23993543

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

    PubMed

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

    2010-01-11

    In this paper, two different methods are for the first time systematically compared for the determination of selenium in human serum selenoalbumin (SeAlb). Firstly, SeAlb was enzymatically hydrolyzed and the resulting selenomethionine (SeMet) was quantified using species-specific isotope dilution (SSID) with reversed phase-HPLC (RP-HPLC) hyphenated to (collision/reaction cell) inductively coupled plasma-quadrupole mass spectrometry (CRC ICP-QMS). In order to assess the enzymatic hydrolysis yield, SeAlb was determined as an intact protein by affinity-HPLC (AF-HPLC) coupled to CRC ICP-QMS. Using this approach, glutathione peroxidase (GPx) and selenoprotein P (SelP) (the two selenoproteins present in serum) were also determined within the same chromatographic run. The levels of selenium associated with SeAlb in three serum materials, namely BCR-637, Seronorm level 1 and Seronorm level 2, obtained using both methods were in a good agreement. Verification of the absence of free SeMet, which interferes with the SeAlb determination (down to the amino acid level), in such materials was addressed by analyzing the fraction of GPx, partially purified by AF-HPLC, using RP-HPLC (GPx only) and size exclusion-HPLC (SE-HPLC) coupled to CRC ICP-QMS. The latter methodology was also used for the investigation of the presence of selenium species other than the selenoproteins in the (AF-HPLC) SelP and SeAlb fractions; the same selenium peaks were detected in both control and BCR-637 serum with a difference in age of ca. 12 years. It is also for the first time that the concentrations of selenium associated with SeAlb, GPx and SelP species in such commercially available serums (only certified or having indicative levels of total selenium content) are reported. Such indicative values can be used for reference purposes in future validation of speciation methods for selenium in human serum and/or inter-laboratory comparisons. PMID:20005320

  16. Platelet Indices of Selenium Status in Healthy and Selenium-Deficient Sheep: a Comparison with Selenium Indices in Plasma, Whole Blood, and Red Blood Cells.

    PubMed

    Dalir-Naghadeh, Bahram; Bahrami, Yaser; Rezaei, Siamak Asri; Anassori, Ehsan; Janalipour, Ali; Khosravi, Voria

    2015-11-01

    Several biomarkers have been used to evaluate selenium (Se) status in livestock. However, there is no report on the potential usefulness of the Se indices of platelets in diagnosis of Se deficiency in large animals. In the current study, Se concentration and glutathione peroxidase (GPx) activity in platelets of 38 healthy and 142 Se-deficient ewes were assessed, and their correlation with plasma Se concentration, plasma GPx activity, whole blood Se concentration, and erythrocyte GPx activity was determined. Receiver operating characteristic (ROC) curve analysis was used to determine the optimal cutoff values of Se concentration and GPx activity of the platelets and to summarize the diagnostic performance of these biomarkers. In Se-deficient ewes, consistent with other indices, Se concentration and GPx activity in platelets were significantly lower than those of the healthy ewes. There was a positive significant correlation between Se concentration and GPx activity in platelets with plasma Se concentration, whole blood Se concentration, and erythrocyte GPx activity. Based on the ROC curve analysis, the best cutoff value to predict inadequate plasma selenium concentration was ≤0.0055 attogram/platelet for the platelet Se concentration, with a sensitivity of 100.0 %, specificity of 92.4 %, and AUC of 0.94. For platelet GPx activity, the cutoff value was ≤203.6 U/g protein with a sensitivity of 97.4 %, specificity of 77.7 %, and AUC of 0.90. The results of this study suggested that the platelet Se concentration and GPx activity can be considered a reliable and valid intermediate-term surrogate parameter in assessment of dietary Se intake in sheep. PMID:25900578

  17. 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

  18. Selenium toxicosis in a flock of Katahdin hair sheep.

    PubMed Central

    Smith, B I; Donovan, G A; Rae, D O

    1999-01-01

    Selenium supplementation by injection is a common practice. Acute toxicosis from dosaging errors may occur. In this report, 23 of 56 ewes and all 24 lambs injected with selenium died. Tissue, whole blood, and serum concentrations aided in the diagnosis. Caution should be taken when supplementing selenium by injection. Images Figure 1. PMID:10086221

  19. 21 CFR 520.2100 - Selenium, vitamin E capsules.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Selenium, vitamin E capsules. 520.2100 Section 520...) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS ORAL DOSAGE FORM NEW ANIMAL DRUGS § 520.2100 Selenium, vitamin... to 1 milligram of selenium) and 56.2 milligrams of vitamin E (68 I.U.) (as d-alpha tocopheryl...

  20. 21 CFR 520.2100 - Selenium, vitamin E capsules.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Selenium, vitamin E capsules. 520.2100 Section 520...) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS ORAL DOSAGE FORM NEW ANIMAL DRUGS § 520.2100 Selenium, vitamin... to 1 milligram of selenium) and 56.2 milligrams of vitamin E (68 I.U.) (as d-alpha tocopheryl...