Showing papers on "Selenium published in 2012"
TL;DR: The crucial factor that needs to be emphasised with regard to the health effects of selenium is the inextricable U-shaped link with status; whereas additional seenium intake may benefit people with low status, those with adequate-to-high status might be affected adversely and should not take selenum supplements.
2,297 citations
Book•
24 Oct 2012
TL;DR: This work focuses on the role of selenium as a cancer preventive agent in the context of HIV/AIDS and its role in cancer etiology through the role in selenoproteins of the glutathione system.
Abstract: List of Contributors. Foreword R.F. Burk. Preface D.L. Hatfield. Acknowledgements.1. Introduction D.L. Hatfield. Part I: Biosynthesis of selenocysteine and its incorporation into protein: 2. Selenium metabolism in bacteria A. Bock. 3. Mammalian selenocysteine tRNA B.A. Carlson, et al. 4. Selenophosphate selenium donor for protein and tRNA G.M. Lacourciere. 5. SECIS elements G.W. Martin III, M.J. Berry. 6. SECIS binding proteins P.R. Copeland, D.M. Driscoll. 7. Towards a mechanism for selenocysteine incorporation in eukaryotes J.B. Mansell, M.J. Berry. 8.Regulation of selenoprotein expression R.A. Sunde. Part II: Selenium-containing proteins: 9. Identity, evolution and function of selenoproteins and selenoprotein genes V.N. Gladyshev. 10. Bacterial selenoenzymes and mechanisms of action T.C. Stadtman. 11. Selenoprotein P K.E. Hill, R.F. Burk. 12. Selenoprotein W: A muscle protein in search of a function L. Walt Ream, et al. 13. The 15 kDa selenoprotein (Sep15): functional studies and a role in cancer etiology V.N. Gladyshev, et al. 14. Selenoproteins of the glutathione system L. Flohe, R. Brigelius-Flohe. 15. Selenoproteins of the thioredoxin system A. Holmgren. 16. Selenium, deiodinases and endocrine function D.L. St. Germain. Part III: Selenium and human health: 17. Selenium as a cancer preventive agent G.F. Combs Jr., Junxuan Lu. 18. Selenium deficiency and human disease R.Th.J. Coppinger, A.M. Diamond. 19. Selenium as an antiviral agent M.A. Beck. 20. Role of selenium in HIV/AIDS M.K. Baum, et al. 21. Effects of selenium on immunity and aging R.C. McKenzie, et al. 22. Selenium and male reproduction L. Flohe, et al. 23. Role of low molecular weight, selenium-containing compounds in human health H.J. Thompson. 24. Evolution of human dietary standards for selenium O.A. Levander. 25. Selenium in Biology and human health: controversies and perspectives V.N. Gladyshev. Index.
561 citations
TL;DR: In this article, a thermoelectric figure-of-merit (ZT) of ∼1.6 at 700°C is achieved in β-phase copper selenide (Cu2Se) made by ball milling and hot pressing.
272 citations
TL;DR: The baseline selenium status of an individual could constitute the most important parameter modifying the outcome of selenum supplementation, which might primarily disrupt self-amplifying cycles of the endocrine–immune system interface rectifying the interaction of lymphocytes with thyroid autoantigens.
Abstract: The trace element selenium is an essential micronutrient that is required for the biosynthesis of selenocysteine-containing selenoproteins. Most of the known selenoproteins are expressed in the thyroid gland, including some with still unknown functions. Among the well-characterized selenoproteins are the iodothyronine deiodinases, glutathione peroxidases and thioredoxin reductases, enzymes involved in thyroid hormone metabolism, regulation of redox state and protection from oxidative damage. Selenium content in selenium-sensitive tissues such as the liver, kidney or muscle and expression of nonessential selenoproteins, such as the glutathione peroxidases GPx1 and GPx3, is controlled by nutritional supply. The thyroid gland is, however, largely independent from dietary selenium intake and thyroid selenoproteins are preferentially expressed. As a consequence, no explicit effects on thyroid hormone profiles are observed in healthy individuals undergoing selenium supplementation. However, low selenium status correlates with risk of goiter and multiple nodules in European women. Some clinical studies have demonstrated that selenium-deficient patients with autoimmune thyroid disease benefit from selenium supplementation, although the data are conflicting and many parameters must still be defined. The baseline selenium status of an individual could constitute the most important parameter modifying the outcome of selenium supplementation, which might primarily disrupt self-amplifying cycles of the endocrine-immune system interface rectifying the interaction of lymphocytes with thyroid autoantigens. Selenium deficiency is likely to constitute a risk factor for a feedforward derangement of the immune system-thyroid interaction, while selenium supplementation appears to dampen the self-amplifying nature of this derailed interaction.
260 citations
TL;DR: The recent findings regarding selenium interaction with other elements extend the understanding of seenium biological functions and highlight se lenium as a potential countermeasure against toxicity induced by arsenic and cadmium.
Abstract: Selenium is an essential trace element for mammals. Through selenoproteins, this mineral participates in various biological processes such as antioxidant defence, thyroid hormone production, and immune responses. Some reports indicate that a human organism deficient in selenium may be prone to certain diseases. Adverse health effects following selenium overexposure, although very rare, have been found in animals and people. Contrary to selenium, arsenic and cadmium are regarded as toxic elements. Both are environmental and industrial pollutants, and exposure to excessive amounts of arsenic or cadmium can pose a threat to many people's health, especially those living in polluted regions. Two other elements, vanadium and chromium(III) in trace amounts are believed to play essential physiological functions in mammals. This review summarizes recent studies on selenium interactions with arsenic and cadmium and selenium interactions with vanadium and chromium in mammals. Human studies have demonstrated that selenium may reduce arsenic accumulation in the organism and protect against arsenic-related skin lesions. Selenium was found to antagonise the prooxidant and genotoxic effects of arsenic in rodents and cell cultures. Also, studies on selenium effects against oxidative stress induced by cadmium in various animal tissues produced promising results. Reports suggest that selenium protection against toxicity of arsenic and cadmium is mediated via sequestration of these elements into biologically inert conjugates. Selenium-dependent antioxidant enzymes probably play a secondary role in arsenic and cadmium detoxification. So far, few studies have evaluated selenium effects on chromium(III) and vanadium actions in mammals. Still, they show that selenium may interact with these minerals. Taken together, the recent findings regarding selenium interaction with other elements extend our understanding of selenium biological functions and highlight selenium as a potential countermeasure against toxicity induced by arsenic and cadmium.
251 citations
TL;DR: Based on a consideration of all experiment indexes, 0.3 to 0.5 mg/kg is suggested to be the optimum level of supplementation of nano-Se, and the maximum supplementation could not be more than 1.0mg/kg in broilers.
189 citations
TL;DR: Stabilized biologically synthetized selenium (0) nanoparticles with size less than 100 nm have a potential application as a food additive with antioxidant properties relevant to human health.
Abstract: The bio-reduction of selenite (Se (IV)) generates nanoparticles with sizes ranging between 30 and 300 nm. Biologic properties of Se nanoparticles, e.g., antioxidant activity, are dependent on the nanoparticle size; smaller particles have greater activity. In this study, the bio-reduction of selenite by Pantoea agglomerans strain UC-32 under aerobic conditions and room temperature to produce bioactive Se nanoparticles smaller than 100 nm was demonstrated. Isolation and purification of the nanoparticles was performed by alkaline lysis. These purified nanoparticles were stabilized with l-cysteine (4 mM). The visualization and characterization of nanoparticles were performed by transmission electron microscopy, energy dispersive X-ray spectroscopy, and scanning electron microscopy. The antioxidant activity of nanoparticles was determined by production of reactive oxygen species using human umbilical vein endothelial cells. Transmission electron microscopy images showed the accumulation of spherical selenium nanoparticles as intracellular and extracellular deposits. The size of Se nanoparticles varied with incubation time. Amorphous Se nanoparticles with size in the order of 100 nm were obtained before 24 h of incubation; but, at 24 h of incubation, the size of the majority of the nanoparticles was in the desirable order of 100 nm and they were not aggregated. Energy dispersive spectroscopy spectra indicated that nanoparticles were composed entirely of selenium. Antioxidant activity of stabilized selenium nanoparticles demonstrated high antioxidant activity when compared to selenite and selenium nanoparticles without stabilization. Stabilized biologically synthetized selenium (0) nanoparticles with size less than 100 nm have a potential application as a food additive with antioxidant properties relevant to human health.
189 citations
TL;DR: Despite being disparaged for their malodorous and toxic demeanour, compounds of selenium, a bio-essential element, and tellurium, offer possibilities as therapeutic agents, and their potential use as drugs, for example, as anti-viral, anti-microbial,Anti-inflammatory agents, etc., is surveyed.
Abstract: Despite being disparaged for their malodorous and toxic demeanour, compounds of selenium, a bio-essential element, and tellurium, offer possibilities as therapeutic agents. Herein, their potential use as drugs, for example, as anti-viral, anti-microbial, anti-inflammatory agents, etc., will be surveyed along with a summary of the established biological functions of selenium. The natural biological functions of tellurium remain to be discovered.
157 citations
TL;DR: It is demonstrated that Se supplementation plays a protective role in a tissue-specific manner and also highlights the importance of TrxR as a main target for mercurials in vivo.
151 citations
TL;DR: Selenium at a lower concentration alleviated Pb toxicity which was accompanied by a decreased O2●− production in the apical parts of roots and increased the T-SH content and GPOX activity, however, higher Se concentration intensified MDA and T- SH accumulation and GPOx and GSH-Px activity in Pb-treated plant roots.
Abstract: The effect of selenium (Se) on Vicia faba L. minor roots subjected to lead (Pb) stress was studied by investigating root growth, root viability, and antioxidant enzyme activity. The experiments were carried out on plants grown for 2 weeks on Hoagland medium supplied with 50 μM Pb in the form of lead nitrate Pb(NO(3))(2) and/or Se concentrations of 1.5 and 6 μM in the form of sodium selenite Na(2)SeO(3). It was shown that Pb reduced the root growth and caused serious damage in the roots, which was accompanied by metal accumulation in these tissues. The exposition of roots to Pb led to significant changes in the biochemical parameters: the MDA and T-SH content and glutathione peroxidase (GSH-Px) activity increased but the guaiacol peroxidase (GPOX) activity decreased. Moreover, Pb intensified O(2)(·-) production in the roots. Selenium at a lower concentration alleviated Pb toxicity which was accompanied by a decreased O(2)(·-) production in the apical parts of roots and increased the T-SH content and GPOX activity. However, higher Se concentration intensified MDA and T-SH accumulation and GPOX and GSH-Px activity in Pb-treated plant roots. At low concentration, Se improved cell viability whereas at high concentration it was pro-oxidant and enhanced the lipid peroxidation and cell membrane injury.
138 citations
TL;DR: In this paper, two experiments were performed to explore the selenium retention of nano elemental Selenium (Nano-Se) in male broiler chickens as compared with sodium selenite in a maize-soybean meal diet.
TL;DR: It was concluded that SY and MS are more effective than SS in increasing the AEA, TAC, and oxidative stability of chicken breast meat.
Abstract: The effects of sodium selenite (SS) and selenium yeast (SY) alone and in combination (MS) on the selenium (Se) content, antioxidant enzyme activities (AEA), total antioxidant capacity (TAC), and oxidative stability of chicken breast meat were investigated. The results showed that the highest (p < 0.05) glutathione peroxidase (GSH-Px) activity was found in the SS-supplemented chicken breast meat; however, SY and MS treatments significantly increased (p < 0.05) the Se content and the activities of catalase (CAT), total superoxide dismutase (T-SOD), and TAC, but decreased (p < 0.05) the malondialdehyde (MDA) content at 42 days of age. Twelve days of storage at 4 °C decreased (p < 0.05) the activity of the GSH-Px, but CAT, T-SOD, and TAC remained stable. SY decreased the lipid oxidation more effectively in chicken breast meat. It was concluded that SY and MS are more effective than SS in increasing the AEA, TAC, and oxidative stability of chicken breast meat.
TL;DR: It is concluded that production of Sepp1 by hepatocytes is central to selenium homeostasis in the organism because it promotes retention of se lenium in the body and effects seenium distribution from the liver to extra-hepatic tissues, especially under selenum-deficient conditions.
TL;DR: In this article, the authors investigated energy-dispersive X-ray fluorescence spectrometry (EDXRF) for the measurement of zinc (Zn), iron (Fe) and selenium (Se) concentrations in whole grain wheat.
Abstract: Background and aims
Crop biofortification programs require fast, accurate and inexpensive methods of identifying nutrient dense genotypes. This study investigated energy-dispersive X-ray fluorescence spectrometry (EDXRF) for the measurement of zinc (Zn), iron (Fe) and selenium (Se) concentrations in whole grain wheat.
TL;DR: It is concluded that GPx2, although supporting tumor growth, inhibits inflammation-mediated tumorigenesis, but the protective effect of selenium does not strictly depend on GPx1 and -2 expression.
Abstract: Chronic inflammation and selenium deficiency are considered as risk factors for colon cancer. The protective effect of selenium might be mediated by specific selenoproteins, such as glutathione peroxidases (GPx). GPx-1 and -2 double knockout, but not single knockout mice, spontaneously develop ileocolitis and intestinal cancer. Since GPx2 is induced by the chemopreventive sulforaphane (SFN) via the nuclear factor E2-related factor 2 (Nrf2)/Keap1 system, the susceptibility of GPx2-KO and wild-type (WT) mice to azoxymethane and dextran sulfate sodium (AOM/DSS)-induced colon carcinogenesis was tested under different selenium states and SFN applications. WT and GPx2-KO mice were grown on a selenium-poor, -adequate or -supranutritional diet. SFN application started either 1 week before (SFN4) or along with (SFN3) a single AOM application followed by DSS treatment for 1 week. Mice were assessed 3 weeks after AOM for colitis and Nrf2 target gene expression and after 12 weeks for tumorigenesis. NAD(P)H:quinone oxidoreductases, thioredoxin reductases and glutathione-S-transferases were upregulated in the ileum and/or colon by SFN, as was GPx2 in WT mice. Inflammation scores were more severe in GPx2-KO mice and highest in selenium-poor groups. Inflammation was enhanced by SFN4 in both genotypes under selenium restriction but decreased in selenium adequacy. Total tumor numbers were higher in GPx2-KO mice but diminished by increasing selenium in both genotypes. SFN3 reduced inflammation and tumor multiplicity in both Se-adequate genotypes. Tumor size was smaller in Se-poor GPx2-KO mice. It is concluded that GPx2, although supporting tumor growth, inhibits inflammation-mediated tumorigenesis, but the protective effect of selenium does not strictly depend on GPx2 expression. Similarly, SFN requires selenium but not GPx2 for being protective.
TL;DR: The results suggest that PEG-SeNPs may be a candidate for further evaluation as a chemotherapeutic agent for drug-resistant liver cancer, and the strategy to use PEG200 as a surface decorator could be a highly efficient way to enhance the anticancer efficacy of nanomaterials.
Abstract: Gray selenium (Se) is one of the most widely used Se sources with very limited biocompatibility and bioactivity. In the present study, a simple method for the preparation of ultrasmall selenium nanoparticles (SeNPs) through direct nanolization of gray selenium by polyethylene glycol (PEG) was demonstrated. Monodisperse and homogeneous PEG-SeNPs with ultrasmall diameters were successfully prepared under optimized conditions. The products were characterized using various microscopic and spectroscopic methods, and the results suggest that the amphoteric properties of PEG and the coordination between oxygen and selenium atoms contributed to the formation of ultrasmall nanoparticles. PEG-SeNPs exhibited stronger growth inhibition on drug-resistant hepatocellular carcinoma (R-HepG2) cells than on normal HepG2 cells. Dose-dependent apoptosis was induced by PEG-SeNPs in R-HepG2 cells, as evidenced by an increase in the sub-G1 cell population. Further investigation on the underlying molecular mechanisms revealed that depletion of mitochondrial membrane potential and generation of superoxide anions contributed to PEG-SeNPs-induced apoptotic cell death in R-HepG2 cells. Our results suggest that PEG-SeNPs may be a candidate for further evaluation as a chemotherapeutic agent for drug-resistant liver cancer, and the strategy to use PEG200 as a surface decorator could be a highly efficient way to enhance the anticancer efficacy of nanomaterials.
TL;DR: Novel insights into Se response in rice at the proteome level are provided, which are expected to be highly useful for dissecting the Se response pathways in higher plants and for producing Se enriched rice cultivars in the future.
12 Sep 2012-Journal of Environmental Science and Health Part C-environmental Carcinogenesis & Ecotoxicology Reviews
TL;DR: This article gathers information from the literature on the consequences of a deficiency and an excess of selenium in the body, as well as the health-promoting mechanisms of Selenium, including the functions ofSelenoproteins.
Abstract: Selenium occurs in the environment in inorganic and organic compounds. For many years it was regarded as a toxic element, causing numerous illnesses and diseases. But research in the past 50 years has revealed a "bright side" to this element, especially as a component of selenoproteins, selenium makes a significant contribution to the health of humans and animals. The selenium content in an organism depends on its concentration and bioavailability in the soil, and the differences between its deficiency, appropriate intake, and excess are very slight. This article gathers information from the literature on: • the consequences of a deficiency and an excess of selenium in the body, as well as the health-promoting mechanisms of selenium, including the functions of selenoproteins • the uptake and transformation of selenium compounds by plants, because of the fact that selenium is better assimilated from plant food and also the classification of plants with respect to their ability to take up selenium from the soil and to accumulate it.
TL;DR: Further studies examining the availability of redox‐active selenium species and their mechanisms and kinetics of action are of critical importance in the potential development of seleno species as a therapeutic strategy.
Abstract: Selenium is a trace element essential for normal physiological processes. Organic selenium-containing amino acids, such as selenocysteine (Sec) / selenocystine and selenomethionine (SeMet, the major dietary form), can provide antioxidant benefits by acting both as direct antioxidants as well as a source of selenium for synthesis of selenium-dependent antioxidant and repair proteins (e.g., glutathione peroxidases, thioredoxin reductases, methionine sulfoxide reductases). The direct antioxidant actions of these amino acids arise from the nucleophilic properties of the ionized selenol (RSe(-), which predominates over the neutral form at physiological pH values) and the ease of oxidation of Sec and SeMet. This results in higher rate constants for reaction with multiple oxidants, than for the corresponding thiols/thioethers. Furthermore, the resulting oxidation products are more readily and rapidly reversed by both enzyme and nonenzymatic reactions. The antioxidant effects of these seleno species can therefore be catalytic. Seleno amino acids may also chelate redox-active metal ions. The presence of Sec in the catalytic site of selenium-dependent antioxidant enzymes enhances the kinetic properties and broadens the catalytic activity of antioxidant enzymes against biological oxidants when compared with sulfur-containing species. However, while normal physiological selenium levels afford protection, when compared with deficiency, excessive selenium may induce damage and adverse effects, with this being manifest, for example, as an increased incidence of type 2 diabetes. Further studies examining the availability of redox-active selenium species and their mechanisms and kinetics of action are therefore of critical importance in the potential development of seleno species as a therapeutic strategy.
TL;DR: Toxicity was more pronounced when inorganic Se was applied than after subacute application of Sel‐Plex, nanoSe, or LactoMicroSe, and a comparison of lowest toxic doses of sodium selenite in mice and mallard indicates that birds are more resistant to Se than rodents.
Abstract: Sixteen groups of mice were fed diets containing different selenium species to compare their toxicity. Inorganic sodium selenate and sodium hydroselenite, elementary nanoSe, organic Sel-Plex, and Lacto-MicroSelenium were administered for 14 d at concentrations of 0.5, 5, and 50 ppm Se, equivalent to 0.5, 5, and 50 mg Se/kg food, corresponding to an estimated 4, 40, and 400 µg/kg body weight/d Se uptake, respectively. At the end of the treatment, body, liver, spleen, kidney, heart, and brain weights were measured, mice were subjected to necropsy, and histological examinations were performed on the liver. At lower Se doses (0.5 and 5 ppm) a moderate reduction was observed in the number of bone marrow and white blood cells and in granulocyte-macrophage colony-forming units (GM-CFUs) relative to the untreated control group of mice. A comparison of lowest toxic doses of sodium selenite in mice (0.5 ppm) and mallard (10 ppm) indicates that birds are more resistant to Se than rodents. In mice, a small but measurable weight loss was observed after 5 ppm selenate and LactoMicroSe treatment. The most significant changes took place after 50-ppm administration in body and spleen weight, hematology, and liver histology. Toxicity was more pronounced when inorganic Se was applied than after subacute application of Sel-Plex, nanoSe, or LactoMicroSe. To summarize the effects, the authors' 14-d murine subacute toxicity study showed that the toxicity of Se species decreased in the following order: selenate > selenite > nanoSe > Sel-Plex > LactoMicroSe.
TL;DR: It is suggested that selenium nanoparticle administration can result in considerable induction of the Th1 platform of immune response through the elevation of IFN-γ and IL-12 and may be a cause for better prognosis in mice with tumors.
Abstract: Selenium salts as well as elemental selenium nanoparticles are attracting the attention of researchers due to their excellent biological properties. The aim of the present work was to study immunomodulation by applying elemental Se NPs to stimulate the immune response of mice bearing 4 T1 breast cancer tumors. Six- to 8-week-old female inbred BALB/c mice were divided into two groups of test and control, each containing 15 mice. Every day, for 2 weeks prior to tumor induction, selenium nanoparticles were orally administered to the mice at a dose of 100 μg/day. Then, 1 × 106 cells from a 4 T1 cell line were injected subcutaneously to each mouse. Oral nanoparticle administration was continued daily for 3 weeks after tumor induction. Different immunological parameters were then evaluated including cytokine level, delayed type hypersensitivity (DTH) response as well as tumor growth and the survival rates in all treated or nontreated animals. The production of Th1 cytokines, such as IFN-γ and IL-12, in spleen cell culture was increased in the test mice-administered selenium nanoparticles. The DTH response of test mice also showed a significant increase when compared to the control mice. The survival rate was notably higher for the selenium nanoparticle-treated mice compared to the control mice. Our results suggest that selenium nanoparticle administration can result in considerable induction of the Th1 platform of immune response through the elevation of IFN-γ and IL-12 and may be a cause for better prognosis in mice with tumors.
TL;DR: A novel coordination-responsive system for the controlled release of doxorubicin was fabricated by complexing platinum cations with selenium-containing polymers, opening a new avenue in multidrug systems for cooperative chemotherapy.
Abstract: A novel coordination-responsive system for the controlled release of doxorubicin was fabricated by complexing platinum cations with selenium-containing polymers. Doxorubicin loaded in the platinum-coordinating micelles can be released in a controlled manner through the competitive coordination of the platinum cations with glutathione. The coordination micelles are quite biocompatible as vehicles of drug delivery, thus opening a new avenue in multidrug systems for cooperative chemotherapy.
TL;DR: In this article, a hydroponic experiment was carried out to investigate the effects of Se on growth, selenium accumulation and some physiological characteristics of spinach (Spinacia oleracea L. cv.
Abstract: Selenium (Se) has been proved to be an essential element for humans and animals. However, less is known about its effects on plants. A hydroponic experiment was carried out to investigate the effects of selenium on growth, selenium accumulation and some physiological characteristics of spinach (Spinacia oleracea L. cv. ‘Missouri’) plants. Plants were grown in Hoagland nutrient solution amended with sodium selenite at 0 (control), 1, 2, 4, 6 and 10 mg.L -1 for 28 days. Growth parameters like shoot and root fresh weight, shoot and root dry weight, total dry weight, shoot and root length increased by 17, 15, 38, 19, 18 and 34 percent in response to the lowest concentration of Se (1 mg L -1 ), respectively over control. However, application of higher Se concentrations reduced these parameters as compared to control. Selenium up to 1 mg L -1 enhanced the levels of chlorophyll a and chlorophyll b by 87 and 165 percent, respectively, while higher levels of Se exert toxic effects. Total phenolic compounds in leaves increased directly by increasing the level of Se and plants treated with 10 mg. L -1 Se had the highest values. Selenium, sodium and calcium content increased, while potassium content decreased, by increasing selenium treatments. The highest amounts of Se in shoots (3.89 mg g -1 DW) and roots (4.27 mg g -1 DW) were obtained for the highest concentration of Se (10 mg L -1 ). The present results suggested the beneficial effects of Se on spinach growth and also its
TL;DR: It is suggested that coating polymers (particularly, polycarbonate) with nanostructured selenium is a fast and effective way to reduce bacteria functions that lead to medical device infections.
Abstract: Biofilms are a common cause of persistent infections on medical devices as they are easy to form and hard to treat The objective of this study was for the first time to coat selenium (a natural element in the body) nanoparticles on the surface of polycarbonate medical devices (such as those used for medical catheters) and to examine their effectiveness at preventing biofilm formation The size and distribution of selenium coatings were characterized using scanning electron microscopy and atomic force microscopy The strength of the selenium coating on polycarbonate was assessed by tape-adhesion tests followed by atomic absorption spectroscopy Results showed that selenium nanoparticles had a diameter of 50–100 nm and were well distributed on the polycarbonate surface In addition, more than 50% of the selenium coating survived the tape-adhesion test as larger nanoparticles had less adhesion strength to the underlying polycarbonate substrate than smaller selenium nanoparticles Most significantly, the results of this in vitro study showed that the selenium coatings on polycarbonate significantly inhibited Staphylococcus aureus growth to 89% and 27% when compared with an uncoated polycarbonate surface after 24 and 72 h, respectively Importantly, this was accomplished without using antibiotics but rather with an element (selenium) that is natural to the human body Thus, this study suggests that coating polymers (particularly, polycarbonate) with nanostructured selenium is a fast and effective way to reduce bacteria functions that lead to medical device infections © 2012 Wiley Periodicals, Inc J Biomed Mater Res Part A: 100A: 3205–3210, 2012
TL;DR: Novel Ag-TiO (2)- and ZrO(2)-based photocatalytic vapor generation (PCVG) systems are reported as effective sample introduction techniques for further improving the sensitivity of the atomic spectrometric determination of selenium for the first time.
Abstract: We reported novel Ag–TiO2- and ZrO2-based photocatalytic vapor generation (PCVG) systems as effective sample introduction techniques for further improving the sensitivity of the atomic spectrometric determination of selenium for the first time, in which the conduction band electron served as a “reductant” to reduce selenium species including SeVI and convert them directly into volatile H2Se, which was easily separated from the sample matrix and underwent more effectively subsequent atomization and/or ionization. These two PCVG systems helped us to overcome the problem encountered in the most conventional KBH4/OH––H+ system, in that SeVI was hardly converted into volatile selenium species without the aid of prereduction procedures. The limits of detection (LODs) (3σ) of the four most typical SeIV, SeVI, selenocystine ((SeCys)2), and selenomethionine (SeMet) species were, respectively, down to 1.2, 1.8, 7.4, and 0.9 ng mL–1 in UV/Ag–TiO2–HCOOH, and 0.7, 1.0, 4.2, and 0.5 ng mL–1 in UV/ZrO2–HCOOH with the re...
TL;DR: The in vitro antioxidant results suggest that selenium-containing polysaccharide should be applied as a novel seenium source in dietary supplements, with potent antioxidant properties.
TL;DR: 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.
Abstract: 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.
TL;DR: The data clearly indicated that red nanoSe was taken up by tobacco callus cultures and rooted tobacco plantlets, and inhibited both callus growth and root regeneration totally in 265–530 μM concentrations.
Abstract: The uptake, accumulation and biological effects of red nano-sized elemental selenium (nanoSe) in comparison to selenate were investigated in plant system at the first time. The data clearly indicated that red nanoSe was taken up by tobacco callus cultures and rooted tobacco plantlets. The roots of regenerated plantlets accumulated selenium in very high concentrations, 2,947 ± 99 mg/kg DW, from the medium containing 530 μM nanoSe. The biological effects of nanoSe were different from the selenate ion in plant tissue culture. NanoSe (265–530 μM concentration range) stimulated the organogenesis and the growth of root system significantly (~40 %) while selenate did not show these effects at any concentration moreover inhibited both callus growth and root regeneration totally in 265–530 μM concentrations.
TL;DR: Investigation of the impact of selenium (Se) on Ulva sp.
TL;DR: Current knowledge of selenate respiration and selenium biomineralization in T. selenatis and other analogous systems are drawn on, and the application of nanoparticle tracking analysis is extended to determine the size distribution profile of the selenum nanospheres secreted.
Abstract: Bacterial anaerobic respiration using selenium oxyanions as the sole electron acceptor primarily result in the precipitation of selenium biominerals observed as either intracellular or extracellular selenium deposits. Although a better understanding of the enzymology of bacterial selenate reduction is emerging, the processes by which the selenium nanospheres are constructed, and in some cases secreted, has remained poorly studied. Thauera selenatis is a Gram-negative betaproteobacterium that is capable of respiring selenate due to the presence of a periplasmic selenate reductase (SerABC). SerABC is a molybdoenzyme that catalyses the reduction of selenate to selenite by accepting electrons from the Q-pool via a dihaem c -type cytochrome (cyt c 4). The product selenite is presumed to be reduced in the cytoplasm, forming intracellular selenium nanospheres that are ultimately secreted into the surrounding medium. The secretion of the selenium nanospheres is accompanied by the export of a ~95 kDa protein SefA (selenium factor A). SefA has no cleavable signal peptide, suggesting that it is also exported directly for the cytoplasmic compartment. It has been suggested that SefA functions to stabilize the formation of the selenium nanospheres before secretion, possibly providing reaction sites for selenium nanosphere creation or providing a shell to prevent subsequent selenium aggregation. The present paper draws on our current knowledge of selenate respiration and selenium biomineralization in T. selenatis and other analogous systems, and extends the application of nanoparticle tracking analysis to determine the size distribution profile of the selenium nanospheres secreted.
Abbreviations: NTA, nanoparticle tracking analysis; QCR, quinol–cytochrome c oxidoreductase; SefA, selenium factor A; SEM, scanning electron microscopy; Ser, periplasmic selenate reductase; TEM, transmission electron microscopy