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Sample records for affects selenium bioavailability

  1. In vivo and in vitro testing for selenium and selenium compounds bioavailability assessment in foodstuff.

    PubMed

    Moreda-Piñeiro, Jorge; Moreda-Piñeiro, Antonio; Bermejo-Barrera, Pilar

    2017-03-04

    The assessment of selenium and selenium species bioavailability in foodstuff is of special concern on the context of human nutrition. In vivo (human and animal), and in vitro tests are important approaches for estimating the bioavailability of toxic and essential compounds to humans. An overview on in vivo and in vitro bioavailability assays for releasing selenium and selenium species in foodstuffs is summarized. Se and Se species content in a foodstuff critically influence Se bioavailability and bioactivity to humans and animals. Se bioavailability is affected by foodstuff-matrix major composition and minor components. Foodstuffs processing and/or treatments could enhancement or decrease Se bioavailability. Experimental conditions such as the selection of healthy status of examined people (in in vivo humans approaches), the selection of animal model (in vivo animals approaches), or the selection of GI conditions (in in vitro tests) could determines the results. Thus, international standardized protocol for in vivo and in vitro approaches assessment is mandatory.

  2. Selenium in soybeans: bioavailability and form

    SciTech Connect

    Mason, A.C.

    1984-01-01

    Experiments are presented which evaluate the bioavailability of different forms of selenium from intrinsically and extrinsically labeled isolated soy protein and soy flour. The bioavailability of selenium from soy and egg is compared and some characteristics of selenium are described as it exists in soybeans. The metabolism of selenium was measured by whole-body and tissue radioactivity retention and selenium excretion. Selenium-75 was well absorbed from an isolated soy protein diet by rats. Selenium-75 from isolated soy protein labeled intrinsically and extrinsically with /sup 75/Se selenate was better absorbed than from protein labeled extrinsically with /sup 75/Se selenite or /sup 75/Se selenomethionine. Bioavailability of selenium from soy flour and egg was measured by whole-body and tissue radioactivity retention and glutathione peroxidase (GSH-Px) activity regeneration. Selenium-75 from soy flour intrinsically labeled with selenite was better absorbed than /sup 75/Se from flour intrinsically labeled with selenate. GSH-Px levels in the liver, kidney, platelets and heart fell when rats were fed a selenium deficient diet, but were not significantly raised on 0.0825 ppm Se repletion diets.

  3. 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.

  4. 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.

  5. Selenium bioavailability and uptake as affected by four different plants in a loamy clay soil with particular attention to mycorrhizae inoculated ryegrass.

    PubMed

    Munier-Lamy, C; Deneux-Mustin, S; Mustin, C; Merlet, D; Berthelin, J; Leyval, C

    2007-01-01

    The aim of this study was to investigate the influence of plant species, especially of their rhizosphere soil, and of inoculation with an arbuscular mycorrhizal (AM) fungus on the bioavailability of selenium and its transfer in soil-plant systems. A pot experiment was performed with a loamy clay soil and four plant species: maize, lettuce, radish and ryegrass, the last one being inoculated or not with an arbuscular mycorrhizal fungus (Glomus mosseae). Plant biomass and Se concentration in shoots and roots were estimated at harvest. Se bioavailability in rhizosphere and unplanted soil was evaluated using sequential extractions. Plant biomass and selenium uptake varied with plant species. The quantity of rhizosphere soil also differed between plants and was not proportional to plant biomass. The highest plant biomass, Se concentration in plants, and soil to plant transfer factor were obtained with radish. The lowest Se transfer factors were obtained with ryegrass. For the latter, mycorrhizal inoculation did not significantly affect plant growth, but reduced selenium transfer from soil to plant by 30%. In unplanted soil after 65 days aging, more than 90% of added Se was water-extractable. On the contrary, Se concentration in water extracts of rhizosphere soil represented less than 1% and 20% of added Se for ryegrass and maize, respectively. No correlation was found between the water-extractable fraction and Se concentration in plants. The speciation of selenium in the water extracts indicated that selenate was reduced, may be under organic forms, in the rhizosphere soil.

  6. In vitro bioavailability of total selenium and selenium species from seafood.

    PubMed

    Moreda-Piñeiro, Jorge; Moreda-Piñeiro, Antonio; Romarís-Hortas, Vanessa; Domínguez-González, Raquel; Alonso-Rodríguez, Elia; López-Mahía, Purificación; Muniategui-Lorenzo, Soledad; Prada-Rodríguez, Darío; Bermejo-Barrera, Pilar

    2013-08-15

    In vitro bioavailability of total selenium and selenium species from different raw seafood has been assessed by using a simulated gastric and intestinal digestion/dialysis method. Inductively coupled plasma-mass spectrometry (ICP-MS) was used to assess total selenium contents after a microwave assisted acid digestion, and also to quantify total selenium in the dialyzable and non-dialyzable fractions. Selenium speciation in the dialyzates was assessed by high performance liquid chromatography (HPLC) coupled with ICP-MS detection. Major Se species (selenium methionine and oxidized selenium methionine) from dialyzate were identified and characterized by HPLC coupled to mass spectrometry (HPLC-MS). Selenocystine was detected at low concentrations while Se-(Methyl)selenocysteine and inorganic selenium species (selenite and selenate) were not detected in the dialyzate. Low bioavailability percentages for total selenium (6.69±3.39 and 5.45±2.44% for fish and mollusk samples, respectively) were obtained. Similar bioavailability percentages was achieved for total selenium as a sum of selenium species (selenocystine plus oxidized selenium methionine and selenium methionine, mainly). HPLC-MS data confirmed SeMet oxidation during the in vitro procedure.

  7. Generation of selenium-enriched rice with enhanced grain yield, selenium content and bioavailability through fertilisation with selenite.

    PubMed

    Wang, Yu-Dong; Wang, Xu; Wong, Yum-Shing

    2013-12-01

    To fulfill the natural human needs of selenium, selenium biofortification has been carried out in rice (Oryza sativa) in recent years. Despite some improvements have been made, the increase of selenium content in rice was still limited and a large amount of fertilisers are often required, which may cause environmental pullution. In this study, we further improved the selenium biofortification of rice by using less selenium fertilisers (10.5 g selenium/hectare) whereas, largely increasing selenium content in rice grains (up to 51 times vs. control). Furthermore, selenium speciation analysis, in vitro gastrointestinal digestion and antioxidant assays were performed to evaluate the selenium bioaccessibility and bioavailability in selenium-enriched rice grains. The major selenium species found were readily absorbable selenomethionine. Meanwhile, the selenium-enriched rice grains have significantly higher antioxidant bioactivities. In conclusion, this selenium-enriched rice has enormous potential for selenium supplementation in humans.

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

    PubMed

    Yan, Lin; Johnson, LuAnn K

    2011-06-08

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

  9. Rumen microorganisms decrease bioavailability of inorganic selenium supplements

    USDA-ARS?s Scientific Manuscript database

    Despite the availaility of selenium (Se)-enriched trace mineral supplements, we have observed low Se status in cattle and sheep offered traditional inorganic Se supplements. Reasons for this may include inadequate intake or low bioavailability of inorganic Se sources. The objective of this study w...

  10. Zinc and selenium accumulation and their effect on iron bioavailability in common bean seeds.

    PubMed

    de Figueiredo, Marislaine A; Boldrin, Paulo F; Hart, Jonathan J; de Andrade, Messias J B; Guilherme, Luiz R G; Glahn, Raymond P; Li, Li

    2017-02-01

    Common beans (Phaseolus vulgaris) are the most important legume crops. They represent a major source of micronutrients and a target for essential trace mineral enhancement (i.e. biofortification). To investigate mineral accumulation during seed maturation and to examine whether it is possible to biofortify seeds with multi-micronutrients without affecting mineral bioavailability, three common bean cultivars were treated independently with zinc (Zn) and selenium (Se), the two critical micronutrients that can be effectively enhanced via fertilization. The seed mineral concentrations during seed maturation and the seed Fe bioavailability were analyzed. Common bean seeds were found to respond positively to Zn and Se treatments in accumulating these micronutrients. While the seed pods showed a decrease in Zn and Se along with Fe content during pod development, the seeds maintained relatively constant mineral concentrations during seed maturation. Selenium treatment had minimal effect on the seed accumulation of phytic acid and polyphenols, the compounds affecting Fe bioavailability. Zinc treatment reduced phytic acid level, but did not dramatically affect the concentrations of total polyphenols. Iron bioavailability was found not to be greatly affected in seeds biofortified with Se and Zn. In contrast, the inhibitory polyphenol compounds in the black bean profoundly reduced Fe bioavailability. These results provide valuable information for Se and Zn enhancement in common bean seeds and suggest the possibility to biofortify with these essential nutrients without greatly affecting mineral bioavailability to increase the food quality of common bean seeds. Published by Elsevier Masson SAS.

  11. Effect of alcohol consumption selenium bioavailability in rats

    SciTech Connect

    Cho, H.K.

    1986-01-01

    This study was done to determine the effects of alcohol consumption on selenium bioavailability in initially Se-depleted rats. Weanling male rats were fed a Se deficient basal diet for 4 weeks and then for the subsequent 4 weeks were supplemented at 0.031 mg Se/Kg or at 0.085 mg Se/Kg of diet in the form of high Se yeast. During the Se repletion period alcohol replaced medium chain triglycerides in the diet at three levels: 0%, 10% and 20% of calories. Dietary Se level significantly affected urinary Se, fecal Se, Se absorption, Se balance whole blood Se, whole blood glutathione peroxidase activity, liver Se concentration, and total liver Se content. Alcohol consumption significantly increased liver Se concentrations and total liver Se in rats fed the adequate Se diet. In rates fed the low Se diet, this pattern was not shown. There was a significant interaction between alcohol and Se level in terms of liver Se concentration and total liver Se. In the first week of Se repletion, fecal Se. Se absorption and Se balance were significantly higher in the 10% alcohol group fed the low Se repletion diet compared to rats given 0% and 20% alcohol in the same Se group. In the final week Se repletion the parameters of Se balance were not affected by alcohol consumption. Alcohol consumption did not influence whole blood Se and whole blood glutathione peroxidase activity; however alcohol consumption significantly reduced growth rate at both Se levels.

  12. Selenium bioavailability of infant milk diets

    SciTech Connect

    Raghib, H.; Chan, W.Y.; Rennert, O.M.

    1986-03-01

    The effects of age, types of milk diet and chemical forms of SE on its bioavailability were studied using suckling rats as a model. Human milk, bovine milk and infant formula (regular Similac) extrinsically labeled with either (/sup 75/Se) selenite or (/sup 75/Se) selenomethionine were fed by gastric intubation to 8, 10, 15 and 20 (or 30)-day-old rats. Retention of /sup 75/Se in gut free carcass and liver was measured 3 hours after feeding. At any given age the corresponding absorption of /sup 75/Se from the 3 diets was similar except at 15 days of age when significantly more (/sup 75/Se) selenomethionine was absorbed from human milk (83%) than from bovine milk or formula (72%). Much higher amount of (/sup 75/Se) selenomethionine was absorbed by any age group from the 3 milk diets compared to (/sup 75/Se) selenite. An age related change in both (/sup 75/Se) selenite and (/sup 75/Se) selenomethionine absorption was noticed in all 3 diets. Gut free carcass (/sup 75/Se) selenite absorption was 32% in 8-d-old rats and increased to 46% in 20-d-old rats. The corresponding liver /sup 75/Se retention was 7.5 and 19.5%. On the other hand, (/sup 75/Se) selenomethionine retention by the gut free carcass decreased with age from an average of 83% in 8-d-old rats to 72% in 20-d-old rats. The corresponding /sup 75/Se incorporation into the liver increased from 15.5% in 8-d-old rats to 21.9% in 20-d-old rats. It is concluded that twice as much /sup 75/Se) selenite and an age related change in /sup 75/Se absorption was noticed between the 2 chemical forms of Se and between human milk and the other 2 milk diets.

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

    USDA-ARS?s Scientific Manuscript database

    We assessed the bioavailability of selenium (Se) from protein isolate and tofu (bean curd) prepared from naturally produced high-Se soybeans in a Se-deficient rat model. The Se content of soybean seeds, protein isolate and tofu was 5.17 ± 0.22, 11.44 ± 0.09 and 7.37 ± 0.12 mg/kg, respectively. Male ...

  14. 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.

  15. Dietary factors affecting polyphenol bioavailability.

    PubMed

    Bohn, Torsten

    2014-07-01

    While many epidemiological studies have associated the consumption of polyphenols within fruits and vegetables with a decreased risk of developing several chronic diseases, intervention studies have generally not confirmed these beneficial effects. The reasons for this discrepancy are not fully understood but include potential differences in dosing, interaction with the food matrix, and differences in polyphenol bioavailability. In addition to endogenous factors such as microbiota and digestive enzymes, the food matrix can also considerably affect bioaccessibility, uptake, and further metabolism of polyphenols. While dietary fiber (such as hemicellulose), divalent minerals, and viscous and protein-rich meals are likely to cause detrimental effects on polyphenol bioaccessibility, digestible carbohydrates, dietary lipids (especially for hydrophobic polyphenols, e.g., curcumin), and additional antioxidants may enhance polyphenol availability. Following epithelial uptake, polyphenols such as flavonoids may reduce phase II metabolism and excretion, enhancing polyphenol bioavailability. Furthermore, polyphenols may act synergistically due to their influence on efflux transporters such as p-glycoprotein. In order to understand polyphenol bioactivity, increased knowledge of the factors affecting polyphenol bioavailability, including dietary factors, is paramount.

  16. Rumen Microorganisms Decrease Bioavailability of Inorganic Selenium Supplements.

    PubMed

    Galbraith, M L; Vorachek, W R; Estill, C T; Whanger, P D; Bobe, G; Davis, T Z; Hall, J A

    2016-06-01

    Despite the availability of selenium (Se)-enriched trace mineral supplements, we have observed low Se status in cattle and sheep offered traditional inorganic Se supplements. Reasons for this may include inadequate intake or low bioavailability of inorganic Se sources. The objective of this study was to determine whether rumen microorganisms (RMO) alter the bioavailability of Se sources commonly used in Se supplements. Rumen microorganisms were isolated from ewes (n = 4) and incubated ex vivo with no Se (control), with inorganic Na selenite or Na selenate, or with organic selenomethionine (SeMet). Total Se incorporated into RMO and the amount of elemental Se formed were determined under equivalent conditions. Incorporation of Se from Na selenite, Na selenate, or SeMet into RMO was measured as fold change compared with control (no added Se). Incorporation of Se into microbial mass was greater for SeMet (13.2-fold greater than no-Se control) compared with inorganic Se supplements (P = 0.02); no differences were observed between inorganic Na selenate (3.3-fold greater than no-Se control) and Na selenite (3.5-fold greater than no-Se control; P = 0.97). Formation of non-bioavailable, elemental Se was less for RMO incubated with SeMet compared with inorganic Se sources (P = 0.01); no differences were observed between Na selenate and Na selenite (P = 0.09). The clinical importance of these results is that the oral bioavailability of organic SeMet should be greater compared with inorganic Se sources because of greater RMO incorporation of Se and decreased formation of elemental Se by RMO.

  17. Influence of estuarine processes on spatiotemporal variation in bioavailable selenium

    USGS Publications Warehouse

    Stewart, Robin; Luoma, Samuel N.; Elrick, Kent A.; Carter, James L.; van der Wegen, Mick

    2013-01-01

    Dynamic processes (physical, chemical and biological) challenge our ability to quantify and manage the ecological risk of chemical contaminants in estuarine environments. Selenium (Se) bioavailability (defined by bioaccumulation), stable isotopes and molar carbon-tonitrogen ratios in the benthic clam Potamocorbula amurensis, an important food source for predators, were determined monthly for 17 yr in northern San Francisco Bay. Se concentrations in the clams ranged from a low of 2 to a high of 22 μg g-1 over space and time. Little of that variability was stochastic, however. Statistical analyses and preliminary hydrodynamic modeling showed that a constant mid-estuarine input of Se, which was dispersed up- and down-estuary by tidal currents, explained the general spatial patterns in accumulated Se among stations. Regression of Se bioavailability against river inflows suggested that processes driven by inflows were the primary driver of seasonal variability. River inflow also appeared to explain interannual variability but within the range of Se enrichment established at each station by source inputs. Evaluation of risks from Se contamination in estuaries requires the consideration of spatial and temporal variability on multiple scales and of the processes that drive that variability.

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

    PubMed

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

    2010-10-01

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

  19. Selenium.

    PubMed

    Barceloux, D G

    1999-01-01

    The 4 natural oxidation states of selenium are elemental selenium (0), selenide (-2), selenite (+4), and selenate (+6). Inorganic selenate and selenite predominate in water whereas organic selenium compounds (selenomethionine, selenocysteine) are the major selenium species in cereal and in vegetables. The principal applications of selenium include the manufacture of ceramics, glass, photoelectric cells, pigments, rectifiers, semiconductors, and steel as well as use in photography, pharmaceutical production, and rubber vulcanizing. High concentrations of selenium in surface and in ground water usually occur in farm areas where irrigation water drains from soils with high selenium content (Kesterson Reservoir, California) or in lakes receiving condenser cooling water from coal-fired electric power plants (Belews Lake, North Carolina). For the general population, the primary pathway of exposure to selenium is food, followed by water and air. Both selenite and selenate possess substantial bioavailability. However, plants preferentially absorb selenates and convert them to organic compounds. Aquatic organisms (e.g., bivalves) can accumulate and magnify selenium in the food chain. Selenium is an essential component of glutathione peroxidase, which is an important enzyme for processes that protect lipids in polyunsaturated membranes from oxidative degradation. Inadequate concentrations of selenium in the Chinese diet account, at least in part, for the illness called Keshan disease. Selenium deficiency occurs in the geographic areas where Balkan nephropathy appears, but there is no direct evidence that selenium deficiency contributes to the development of this chronic, progressive kidney disease. Several lines of scientific inquiry suggest that an increased risk of cancer occurs as a result of low concentrations of selenium in the diet; however, insufficient evidence exists at the present time to recommend the use of selenium supplements for the prevention of cancer. The

  20. Effect of alcohol consumption on selenium (Se) bioavailability in rats

    SciTech Connect

    Cho, H.K.; Snook, J.T.; Yang, F.L.

    1986-03-01

    This study was done to determine the effects of alcohol ingestion on Se bioavailability in initially Se-depleted rats. Weanling male rats were fed a Se deficient (0.012 mg/kg) basal diet for 4 weeks and then for the subsequent 4 weeks were supplemented at 0.031 mg Se/kg or at 0.085 mg Se/kg of diet in the form of high Se yeast. During the Se repletion period alcohol replaced medium chain triglycerides in the diet at 3 levels: 0%, 10%, and 20% of calories. Dietary Se level significantly (P < .0001) affected urinary Se, fecal Se, Se absorption, Se balance, whole blood Se, whole blood glutathione peroxidase activity, and liver Se. In rats fed the higher Se diet total liver Se increased 50% when 20% rather than 0% alcohol was given. In rats fed the lower Se diet total liver Se decreased 12% as dietary alcohol increased from 0 to 20%. There was a significant (P < .0015) interaction between alcohol and Se level. All the other parameters for Se bioavailability were not affected by alcohol consumption. However, alcohol consumption significantly reduced growth rate at both Se levels.

  1. Entrapped elemental selenium nanoparticles affect physicochemical properties of selenium fed activated sludge.

    PubMed

    Jain, Rohan; Seder-Colomina, Marina; Jordan, Norbert; Dessi, Paolo; Cosmidis, Julie; van Hullebusch, Eric D; Weiss, Stephan; Farges, François; Lens, Piet N L

    2015-09-15

    Selenite containing wastewaters can be treated in activated sludge systems, where the total selenium is removed from the wastewater by the formation of elemental selenium nanoparticles, which are trapped in the biomass. No studies have been carried out so far on the characterization of selenium fed activated sludge flocs, which is important for the development of this novel selenium removal process. This study showed that more than 94% of the trapped selenium in activated sludge flocs is in the form of elemental selenium, both as amorphous/monoclinic selenium nanospheres and trigonal selenium nanorods. The entrapment of the elemental selenium nanoparticles in the selenium fed activated sludge flocs leads to faster settling rates, higher hydrophilicity and poorer dewaterability compared to the control activated sludge (i.e., not fed with selenite). The selenium fed activated sludge showed a less negative surface charge density as compared to the control activated sludge. The presence of trapped elemental selenium nanoparticles further affected the spatial distribution of Al and Mg in the activated sludge flocs. This study demonstrated that the formation and subsequent trapping of elemental selenium nanoparticles in the activated sludge flocs affects their physicochemical properties.

  2. [Acute toxicity and bioavailability of nano red elemental selenium].

    PubMed

    Gao, X; Zhang, J; Zhang, L

    2000-01-30

    The reaction ratio of nano red elemental selenium (nanose) with GSH in vitro was one-tenth of that of sodium selenite. Mice were fed with nanose and sodium selenite separately at 50 micrograms/kg BW for 30 days. Both selenium forms could significantly increased Se concentration of blood, liver and activity of blood GSH-Px. Acute toxicity experiment of mice implied that the acute toxicity of nanose was nearly one-seventh of that of sodium selenite. The LD50 for nanose se was 112.98 mg kg BW, and the LD50 for sodium selenite was Se 15.72 mg/kg BW. The acute toxicity of nanose was low for mice.

  3. Organic and inorganic selenium: I. Oral bioavailability in ewes.

    PubMed

    Hall, J A; Van Saun, R J; Bobe, G; Stewart, W C; Vorachek, W R; Mosher, W D; Nichols, T; Forsberg, N E; Pirelli, G J

    2012-02-01

    Although the essentiality of dietary Se for sheep has been known for decades, the chemical source and Se dosage for optimal health remain unclear. In the United States, the Food and Drug Administration (FDA) regulates Se supplementation, regardless of the source of Se, at 0.3 mg of Se/kg of diet (as fed), which is equivalent to 0.7 mg of Se/d or 4.9 mg of Se/wk per sheep. The objectives of this study were to evaluate the effects of Se source (inorganic vs. organic) and supplementation rate (FDA vs. supranutritional rates of 14.7 and 24.5 mg of Se/wk) on whole-blood (WB) and serum-Se concentrations. Mature ewes (n = 240) were randomly assigned to 8 treatment groups (n = 30 each) based on Se supplementation rate (4.9, 14.7, and 24.5 mg of Se•wk(-1)•sheep(-1)) and source [Na-selenite, Na-selenate (4.9 mg/wk only), and organic Se-yeast] with a no-Se control group (0 mg of Se/wk). Treatment groups were balanced for healthy and footrot-affected ewes. For 1 yr, ewes were individually dosed once weekly with 0, 4.9, 14.7, or 24.5 mg of Se, quantities equivalent to their summed daily supplementation rates. Serum- and WB-Se concentrations were measured every 3 mo in all ewes; additionally, WB-Se concentrations were measured once monthly in one-half of the ewes receiving 0 or 4.9 mg of Se/wk. Ewes receiving no Se showed a 78.8 and 58.8% decrease (P < 0.001) in WB- (250 to 53 ng/mL) and serum- (97 to 40 ng/mL) Se concentrations, respectively, over the duration of the study. Whole-blood Se decreased primarily during pregnancy (-57%; 258 to 111 ng/mL) and again during peak lactation (-44%; 109 to 61 ng/mL; P < 0.001). At 4.9 mg of Se/wk, Se-yeast (364 ng/mL, final Se concentration) was more effective than Na-selenite (269 ng/mL) at increasing WB-Se concentrations (P < 0.001). Supranutritional Se-yeast dosages increased WB-Se concentrations in a dose-dependent manner (563 ng/mL, 14.7 mg of Se/wk; 748 ng/mL, 24.5 mg of Se/wk; P < 0.001), whereas WB-Se concentrations were not

  4. Protonation of epigallocatechin-3-gallate (EGCG) results in massive aggregation and reduced oral bioavailability of EGCG-dispersed selenium nanoparticles.

    PubMed

    Wu, Shanshan; Sun, Kang; Wang, Xin; Wang, Dongxu; Wan, Xiaochun; Zhang, Jinsong

    2013-07-31

    The current results show that epigallocatechin-3-gallate (EGCG), in the form of phenolic anions at pH 8.0, can effectively disperse selenium nanoparticles. However, at gastric juice pH (1.0), the EGCG-dispersed selenium nanoparticles (referred to as E-Se) extensively aggregated, so that nano features largely disappeared. This demonstrates that deprotonated phenolic anions of EGCG play an important role in maintaining E-Se stability and suggests that E-Se would suffer from reduced oral bioavailability. To validate this conjecture, size-equivalent E-Se and bovine serum albumin (BSA)-dispersed selenium nanoparticles (B-Se), whose physicochemical properties were not altered at pH 1.0, were orally administered to selenium-deficient mice. In comparison to B-Se, the bioavailabilities of E-Se as indicated with hepatic and renal glutathione peroxidase activity and hepatic selenium levels were significantly (p < 0.01) reduced by 39, 32, and 31%, respectively. Therefore, the present study reveals that size-equivalent selenium nanoparticles prepared by different dispersers do not necessarily guarantee equivalent oral bioavailability.

  5. Selenium Bioavailability from Soy Protein Isolate and Tofu in Rats Fed a Torula Yeast-Based Diet

    USDA-ARS?s Scientific Manuscript database

    Selenium (Se) is an essential nutrient, and soy is a major plant source of dietary protein to humans. The United States produces one-third of world’s soybeans, and the Se-rich Northern Plains produce a large share of the nation’s soybeans. The present study used a rat model to determine the bioavail...

  6. 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.

  7. Mercury and Selenium in a Mining-Affected Watershed of the Rocky Mountain Northwest

    NASA Astrophysics Data System (ADS)

    Langner, H.

    2011-12-01

    The moderating effect of selenium on mercury toxicity is well established, although mechanisms and environmental implications of this interaction are still a field of intensive research. The Upper Clark Fork River Basin in northwestern Montana offers a suitable field site to test some of the emerging models, as a history of intensive metals mining created sub-watersheds with variable combinations of mercury and selenium sources. To address various levels of the food web, we analyzed a preliminary set of sediments, fish tissues and osprey (Pandion haliaetus) blood samples from various locations throughout the watershed. Sediment mercury concentrations vary between 0.02 and over 10 mg/kg, and selenium in sediments ranges from undetectable to 5 mg/kg in the most contaminated reaches. Mercury levels in fish range from 0.03 to 1.5 mg/kg (wet wt) and are highly dependent on the geographic location, in addition to fish species and size. Mercury concentrations in blood of nestling osprey chicks vary between 97 and 730 μg/L, with the majority of the variability explained by geographic location. Total mercury concentration in sediment can explain some of the variability in fish and ospreys; however, mercury accumulation in these organisms is also affected by factors such as the environmental methylation potential and possibly the sequestration of mercury in selenium compounds that are not prone to biomagnification in the food web. This hypothesis is supported by the geographic distribution of selenium and mercury levels in osprey blood: Relatively high selenium concentrations (~2000 μg/L) are associated with the lowest blood mercury levels, despite relatively high mercury levels in the local sediments (~1 mg/kg). In reaches with the lowest selenium concentrations in osprey blood (430 μg/L), the blood mercury levels are relatively high, despite very low sediment mercury levels. Analysis of this data points toward the role of bioavailable selenium in modifying the fate of

  8. The bioavailability of selenium and risk assessment for human selenium poisoning in high-Se areas, China.

    PubMed

    Qin, Hai-bo; Zhu, Jian-ming; Liang, Liang; Wang, Ming-shi; Su, Hui

    2013-02-01

    Enshi prefecture of Hubei Province is well known for human selenium (Se) poisoning in the early 1960s in China. Sporadic cases of Se poisoning in livestocks are still being found. In this study, Se levels in water, cropland soils and various crops from high-Se areas of Enshi were measured to investigate the distribution and bioavailability of Se in the environments, as well as probable daily intake (PDI) of Se for local residents. The total Se in surface water ranged from 2.0 to 519.3μg/L with a geometric mean of 46.0±127.8 μg/L (n=48), 70.5-99.5% of which was present in the form of Se(VI). The soil Se concentration varied from 2.89 to 87.3 μg/g with a geometric mean of 9.36±18.6 μg/g (n=45), and most of Se was associated with organic matter (OM-Se). The total Se in rice, corn, and vegetable samples were 2.11±2.87 μg/g (n=21), 3.76±11.6 μg/g (n=16), and 2.09±3.38 μg/g (n=25), respectively. Stream water Se is likely leached from carbonaceous shale and mine wastes, leading to Se accumulation in paddy soils. OM-Se may play an important role in Se uptake by rice plant in high-Se area of Enshi. The PDI of Se is approximately 2144 μg/day, and Se concentration in blood is estimated at about 3248 μg/L, posing a potential chronic Se poisoning risk to local residents. Cereal consumption (48.5%) makes a great contribution to human daily Se intake, followed by vegetables (36.6%), meats (8.5%), and drinking water (6.4%). However, when assessing health risk on human in high-Se areas, the contribution of drinking water to daily Se intake cannot be ignored due to high Se content and dominant Se(VI) species. Local inhabitants should be advised not to grow crops in high-Se lands or irrigate using high-Se water. If possible, they should drink pipe water and consume foods mixed with those from outside the high-Se areas. Copyright © 2012 Elsevier Ltd. All rights reserved.

  9. Selenium addition alters mercury uptake, bioavailability in the rhizosphere and root anatomy of rice (Oryza sativa)

    PubMed Central

    Wang, Xun; Tam, Nora Fung-Yee; Fu, Shi; Ametkhan, Aray; Ouyang, Yun; Ye, Zhihong

    2014-01-01

    Background and Aims Mercury (Hg) is an extremely toxic pollutant, especially in the form of methylmercury (MeHg), whereas selenium (Se) is an essential trace element in the human diet. This study aimed to ascertain whether addition of Se can produce rice with enriched Se and lowered Hg content when growing in Hg-contaminated paddy fields and, if so, to determine the possible mechanisms behind these effects. Methods Two cultivars of rice (Oryza sativa, japonica and indica) were grown in either hydroponic solutions or soil rhizobags with different Se and Hg treatments. Concentrations of total Hg, MeHg and Se were determined in the roots, shoots and brown rice, together with Hg uptake kinetics and Hg bioavailability in the soil. Root anatonmy was also studied. Key Results The high Se treatment (5 μg g–1) significantly increased brown rice yield by 48 % and total Se content by 2·8-fold, and decreased total Hg and MeHg by 47 and 55 %, respectively, compared with the control treatments. The high Se treatment also markedly reduced ‘water-soluble’ Hg and MeHg concentrations in the rhizosphere soil, decreased the uptake capacity of Hg by roots and enhanced the development of apoplastic barriers in the root endodermis. Conclusions Addition of Se to Hg-contaminated soil can help produce brown rice that is simultaneously enriched in Se and contains less total Hg and MeHg. The lowered accumulation of total Hg and MeHg appears to be the result of reduced bioavailability of Hg and production of MeHg in the rhizosphere, suppression of uptake of Hg into the root cells and an enhancement of the development of apoplastic barriers in the endodermis of the roots. PMID:24948669

  10. Selenium addition alters mercury uptake, bioavailability in the rhizosphere and root anatomy of rice (Oryza sativa).

    PubMed

    Wang, Xun; Tam, Nora Fung-Yee; Fu, Shi; Ametkhan, Aray; Ouyang, Yun; Ye, Zhihong

    2014-08-01

    Mercury (Hg) is an extremely toxic pollutant, especially in the form of methylmercury (MeHg), whereas selenium (Se) is an essential trace element in the human diet. This study aimed to ascertain whether addition of Se can produce rice with enriched Se and lowered Hg content when growing in Hg-contaminated paddy fields and, if so, to determine the possible mechanisms behind these effects. Two cultivars of rice (Oryza sativa, japonica and indica) were grown in either hydroponic solutions or soil rhizobags with different Se and Hg treatments. Concentrations of total Hg, MeHg and Se were determined in the roots, shoots and brown rice, together with Hg uptake kinetics and Hg bioavailability in the soil. Root anatonmy was also studied. The high Se treatment (5 μg g(-1)) significantly increased brown rice yield by 48 % and total Se content by 2·8-fold, and decreased total Hg and MeHg by 47 and 55 %, respectively, compared with the control treatments. The high Se treatment also markedly reduced 'water-soluble' Hg and MeHg concentrations in the rhizosphere soil, decreased the uptake capacity of Hg by roots and enhanced the development of apoplastic barriers in the root endodermis. Addition of Se to Hg-contaminated soil can help produce brown rice that is simultaneously enriched in Se and contains less total Hg and MeHg. The lowered accumulation of total Hg and MeHg appears to be the result of reduced bioavailability of Hg and production of MeHg in the rhizosphere, suppression of uptake of Hg into the root cells and an enhancement of the development of apoplastic barriers in the endodermis of the roots. © The Author 2014. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  11. Bioavailable nanoparticles obtained in laser ablation of a selenium target in water

    SciTech Connect

    Kuzmin, P G; Shafeev, Georgii A; Voronov, Valerii V; Raspopov, R V; Arianova, E A; Trushina, E N; Gmoshinskii, I V; Khotimchenko, S A

    2012-11-30

    The process of producing colloidal solutions of selenium nanoparticles in water using the laser ablation method is described. The prospects of using nanoparticles of elementary selenium as a nutrition source of this microelement are discussed. (nanoparticles)

  12. Imaging translocation and transformation of bioavailable selenium by Stanleya pinnata with X-ray microscopy.

    PubMed

    Amos, Wren; Webb, Samuel; Liu, Yijin; Andrews, Joy C; LeDuc, Danika L

    2012-09-01

    Selenium hyperaccumulator Stanleya pinnata, Colorado ecotype, was supplied with water-soluble and biologically available selenate or selenite. Selenium distribution and tissue speciation were established using X-ray microscopy (micro-X-ray fluorescence and transmission X-ray microscopy) in two dimensions and three dimensions. The results indicate that S. pinnata tolerates, accumulates, and volatilizes significant concentrations of selenium when the inorganic form supplied is selenite and may possess novel metabolic capacity to differentiate, metabolize, and detoxify selenite concentrations surpassing field concentrations. The results also indicate that S. pinnata is a feasible candidate to detoxify selenium-polluted soil sites, especially locations with topsoil polluted with soluble and biologically available selenite.

  13. 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.

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

    PubMed

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

    2009-12-23

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

  15. Lansoprazole does not affect the bioavailability of oral contraceptives.

    PubMed Central

    Fuchs, W; Sennewald, R; Klotz, U

    1994-01-01

    The effects of the proton pump inhibitor lansoprazole on the bioavailability of a low-dose oral contraceptive (OC), containing 0.03 mg ethinyloestradiol (EE) and 0.15 mg levonorgestrel (LNG), were investigated. Twenty-four healthy females (aged 19-35 years; weight 60.6 +/- 7.1 kg) participated in a multiple-dose, placebo-controlled, randomized two-way cross-over study. All subjects received the OC over 2 full menstrual cycles from day 1 to day 21 separated by a drug-free interval of 7 days. Lansoprazole (60 mg day-1) or placebo was coadministered for 3 weeks each. Plasma concentrations of EE and LNG were determined by GC-MS. The 90% confidence intervals for ratios of Cmax and AUC after log transformation of both EE and LNG ranged between 91 and 111%, indicating that lansoprazole did not affect the bioavailability of EE and LNG. PMID:7833230

  16. Lansoprazole does not affect the bioavailability of oral contraceptives.

    PubMed

    Fuchs, W; Sennewald, R; Klotz, U

    1994-10-01

    The effects of the proton pump inhibitor lansoprazole on the bioavailability of a low-dose oral contraceptive (OC), containing 0.03 mg ethinyloestradiol (EE) and 0.15 mg levonorgestrel (LNG), were investigated. Twenty-four healthy females (aged 19-35 years; weight 60.6 +/- 7.1 kg) participated in a multiple-dose, placebo-controlled, randomized two-way cross-over study. All subjects received the OC over 2 full menstrual cycles from day 1 to day 21 separated by a drug-free interval of 7 days. Lansoprazole (60 mg day-1) or placebo was coadministered for 3 weeks each. Plasma concentrations of EE and LNG were determined by GC-MS. The 90% confidence intervals for ratios of Cmax and AUC after log transformation of both EE and LNG ranged between 91 and 111%, indicating that lansoprazole did not affect the bioavailability of EE and LNG.

  17. Factors affecting the selenium intake of people in Transbaikalian Russia.

    PubMed

    Aro, A; Kumpulainen, J; Alfthan, G; Voshchenko, A V; Ivanov, V N

    1994-03-01

    The selenium concentration in foods grown and consumed and in plasma, red blood cells, and toenails of people living in the district of Chita in the transbaikalian part of Russia were studied in August 1991. Preliminary results from the area have suggested low selenium intakes and the possible occurrence of cardiomyopathy (Keshan disease) in the population. A low selenium concentration in foods grown locally was found: mean selenium concentration in wheat grains was 1, 5, and 28 micrograms/kg, respectively, in three villages studied, that of oats was between 3-6 micrograms/kg, and of cow's milk 10-27 micrograms/kg dry matter. The selenium concentration of bread was considerably higher, between 87-337 micrograms/kg dry wt, presumably because wheat imported from the US had been used for baking. Occasional samples of pork, beef, and mutton contained between 32-218 micrograms selenium/kg dry wt. Low selenium concentrations were observed in samples of soil and river water. The mean plasma selenium concentration of 52 persons was 1.02 mumol/L, including 33 children and 19 adult subjects. The selenium concentrations in red blood cells and toenails were 1.95 mumol/L and 0.61 mg/kg, respectively. No symptoms of heart disease caused by selenium deficiency were observed. It is concluded that the selenium status of people was fairly good thanks to the contribution to dietary intake of imported wheat with a high selenium content. As the selenium concentration was very low in foods grown in the area, the selenium intake of the population will be reduced to a very low level if only locally produced foods are consumed.

  18. Selenium geochemistry in reclaimed phosphate mine soils and its relationship with plant bioavailability

    USDA-ARS?s Scientific Manuscript database

    Background and Aims Selenium contamination and accumulation in vegetation have resulted in Se toxicity in livestock and wildlife in reclaimed phosphate mine soils in Southeastern Idaho. Methods Plant and soil samples were collected from five study sites near phosphate mines. Soil physiochemical pr...

  19. The Effect of Zinc and Selenium Supplementation Mode on Their Bioavailability in the Rat Prostate. Should Administration Be Joint or Separate?

    PubMed Central

    Daragó, Adam; Sapota, Andrzej; Nasiadek, Marzenna; Klimczak, Michał; Kilanowicz, Anna

    2016-01-01

    It is thought that zinc and selenium deficiency may play a significant role in the etiology of prostate cancer. Although joint zinc and selenium supplementation is frequently applied in the prevention of prostate diseases, the bioavailability of these elements in the prostate after co-administration is still unknown. The study examines the effect of subchronic supplementation of zinc gluconate and selenium compounds (sodium selenite or selenomethionine), administered together or separately, on their bioavailability in the prostate, as well as the induction of metallothionein-like proteins (MTs) bound to zinc in the prostate and liver. Zinc concentration in the dorso-lateral lobe of the prostate was significantly elevated already after the first month of supplementation of zinc alone. In the supplementation period, the MTs level increased together with zinc concentration. In contrast, the ventral lobe of the prostate did not demonstrate significantly higher levels of zinc until after three months of supplementation, despite the MTs induction noted after one-month supplementation. Increased selenium levels in the dorsolateral lobe were observed throughout the administration and post-administration periods, regardless of the selenium compound used or whether zinc was co-administered. The results of our studies suggested for the first time that these elements should not be administered jointly in supplementation. PMID:27782038

  20. Bioavailability of co-supplemented organic and inorganic zinc and selenium sources in a white fishmeal-based rainbow trout (Oncorhynchus mykiss) diet.

    PubMed

    Rider, S A; Davies, S J; Jha, A N; Clough, R; Sweetman, J W

    2010-02-01

    The bioavailability of trace elements in fishmeal diets is influenced by their chemical forms and dietary anti-nutritional factors. In formulated fish feed, supplemented organically bound minerals may be more bioavailable than inorganic minerals. A 10-week feeding trial was undertaken with rainbow trout (Oncorhynchus mykiss) to determine whether the inclusion of organically bound selenium (Se) and zinc (Zn) improved uptake and assimilation of these elements compared to commonly used inorganic forms. The three diets tested included a control diet, no added Zn or Se; an organic Se-yeast and Zn-proteinate supplemented diet; and an inorganic sodium selenite and Zn-sulphate supplemented diet. The endpoints tested were apparent digestibility, whole body levels, tissue distribution and Se- and Zn-dependent enzyme activities. Digestibility of residual Se in the basal diet was 54.2 +/- 1.0% and supplemented Se-yeast was significantly more digestible than selenite (p < 0.05). Digestibility of residual Zn was 21.9 +/- 2.0% and no significant difference was found between the treatments (p = 0.89). Whole body Se was raised by both Se sources and to a greatest extent by Se-yeast (p < 0.001). Zn-sulphate, and to a lesser extent Zn-proteinate, both raised whole body Zn (p < 0.05). Dietary Zn in the basal diet was found to be above requirements, yet Zn-sulphate had a significantly greater retention than Zn-proteinate in those tissues that responded to Zn supplementation. Se-yeast significantly raised Se in all tissues to a greater extent than selenite, except in the pyloric caeca and liver where the greatest increases were by selenite. Only Se-yeast elevated Se-dependent thioredoxin reductase activity (p < 0.05) and neither forms of Se affected glutathione peroxidise activity (p = 0.059). Alkaline phosphatase and carboxypeptidase B were not affected by Zn supplementation (p = 0.51 and p = 0.88 respectively). In all aspects, Se-yeast was found to be a highly bioavailable form of Se

  1. Bioavailability of selenium from veal, chicken, beef, pork, lamb, flounder, tuna, selenomethionine, and sodium selenite assessed in selenium-deficient rats.

    PubMed

    Wen, H Y; Davis, R L; Shi, B; Chen, J J; Chen, L; Boylan, M; Spallholz, J E

    1997-01-01

    The bioavailability of selenium (Se) from veal, chicken, beef, pork, lamb, flounder, tuna, selenomethionine (SeMet), and sodium selenite was assessed in Se-deficient Fischer-344 rats. Se as veal, chicken, beef, pork, lamb, flounder, tuna, SeMet, and sodium selenite was added to torula yeast (TY) basal diets to comprise Se-inadequate (0.05 mg Se/kg) diets. Se as sodium selenite was added to a TY basal diet to comprise a Se-adequate (0.10 mg Se/kg), Se-control diet. The experimental diets were fed to weanling Fischer-344 rats that had been subjected to dietary Se depletion for 6 wk. After 9 wk of the dietary Se repletion, relative activity of liver glutathione peroxidase (GSHPx) from the different dietary groups compared with control rats (100%) was: flounder 106%, tuna 101%, pork 86%, sodium selenite 81%, SeMet 80%, beef 80%, chicken 77%, veal 77%, and lamb 58%. Se from flounder was the most efficient at restoring Se concentrations in the liver and skeletal muscle. Se from sodium selenite, SeMet, beef, veal, chicken, pork, lamb, and tuna was not dietarily sufficient to restore liver and muscle Se after 9 wk of recovery following a 6-wk period of Se depletion.

  2. Factors affecting sequestration and bioavailability of phenanthrene in soils

    SciTech Connect

    White, J.C.; Kelsey, J.W.; Hatzinger, P.B.; Alexander, M.

    1997-10-01

    A study was conducted to determine factors affecting the sequestration and changes in bioavailability as phenanthrene persists in soils. Phenanthrene became sequestered in seven soils differing appreciably in organic matter and clay content as measured by earthworm uptake, bacterial mineralization, or extractability. Phenanthrene also became sequestered as it aged in soil aggregates of various sizes as measured by decline in availability to a bacterium, a mild extractant, or both. Wetting and drying a soil during aging reduced the amount of phenanthrene recovered by a mild extractant and the rate and extent of bacterial mineralization of the hydrocarbon. After biodegradation of phenanthrene added to the soil, more of the compound remained if it had been aged than if it had not been aged. Wetting and drying the soil during aging further increased the amount of phenanthrene remaining after biodegradation. The rate and extent of bacterial mineralization of phenanthrene were less in leached than in unleached soil. Aging/sequestration is thus markedly affected by soil properties and environmental factors.

  3. Mineralogy affects geoavailability, bioaccessibility and bioavailability of zinc

    PubMed Central

    Molina, Ramon M.; Schaider, Laurel A.; Donaghey, Thomas C.; Shine, James P.; Brain, Joseph D.

    2013-01-01

    We correlated mineralogical and particle characteristics of Zn-containing particles with Zn geoavailability, bioaccessibility, and bioavailability following gavage and intranasal (IN) administration in rats. We compared samples of Zn/Pb mine waste and five pulverized pure-phase Zn minerals (<38 μm). Particles were neutron-activated to produce radioactive 65Zn. We assessed geoavailability using sequential extractions and bioaccessibility using in vitro extraction tests simulating various pH and biological conditions. Zn in vivo bioavailability and in vitro bioaccessibility decreased as follows: mine waste > hydrozincite > hemimorphite > zincite ≈ smithsonite ≫ sphalerite. We found significant correlations among geoavailability, bioaccessibility and bioavailability. In particular, Zn bioavailability post-gavage and post-IN was significantly correlated with bioaccessibility in simulated phagolysosomal fluid and gastric fluid. These data indicate that solid phase speciation influences biological uptake of Zn and that in vitro tests can be used to predict Zn bioavailability in exposure assessment and effective remediation design. PMID:23933126

  4. Mineralogy affects geoavailability, bioaccessibility and bioavailability of zinc.

    PubMed

    Molina, Ramon M; Schaider, Laurel A; Donaghey, Thomas C; Shine, James P; Brain, Joseph D

    2013-11-01

    We correlated mineralogical and particle characteristics of Zn-containing particles with Zn geoavailability, bioaccessibility, and bioavailability following gavage and intranasal (IN) administration in rats. We compared samples of Zn/Pb mine waste and five pulverized pure-phase Zn minerals (<38 μm). Particles were neutron-activated to produce radioactive (65)Zn. We assessed geoavailability using sequential extractions and bioaccessibility using in vitro extraction tests simulating various pH and biological conditions. Zn in vivo bioavailability and in vitro bioaccessibility decreased as follows: mine waste > hydrozincite > hemimorphite > zincite ≈ smithsonite > sphalerite. We found significant correlations among geoavailability, bioaccessibility and bioavailability. In particular, Zn bioavailability post-gavage and post-IN was significantly correlated with bioaccessibility in simulated phagolysosomal fluid and gastric fluid. These data indicate that solid phase speciation influences biological uptake of Zn and that in vitro tests can be used to predict Zn bioavailability in exposure assessment and effective remediation design.

  5. Speciation and bioavailability of selenium and antimony in non-flooded and wetland soils: a review.

    PubMed

    Nakamaru, Yasuo M; Altansuvd, Javkhlantuya

    2014-09-01

    Studies on the sorption behaviors of selenium (Se) and antimony (Sb) are reviewed. Both Se and Sb chemical speciation can be controlled by pH and redox potential, and both of them are likely to be sorbed onto oxy-hydroxides of aluminum, iron or manganese in soils. For agricultural soils especially, there are important physico-chemical and biological differences between non-flooded and wetland soils. Se forms Se(VI), Se(IV), Se(0), Se(-II), and organic Se species at soil pH and redox conditions. Under non-flooded conditions Se solubility is governed by an adsorption mechanism onto metal oxy-hydroxides rather than by precipitation and dissolution reactions; however, for the conditions of wetland soils, it can be expected that Se(0) and organic matter-bound Se play an important role. For Sb, in the soil environment, the dominant Sb forms are Sb(III) and Sb(V). Under aerobic soil conditions, Sb(III) is likely to be oxidized to Sb(V), and the dominant sorbed Sb species should be Sb(V). Under reducing conditions Sb mobility should be lower than under oxidizing conditions due to the lower mobility of Sb(III); however, reduction of Fe and Mn oxides could lead to dissolution of Fe and Mn-bound Sb. This indicates that the risk of Sb contamination to the food chain could be increased in wetland systems.

  6. Determination of selenium bioavailability to a benthic bivalve from particulate and solute pathways

    USGS Publications Warehouse

    Luoma, S.N.; Johns, C.; Fisher, N.S.; Steinberg, N.A.; Oremland, R.S.; Reinfelder, J.R.

    1992-01-01

    Particulate organo-Se was assimilated with 86% efficiency by the deposit feeding bivalve Macoma balthica, when the clam was fed 75Se-labeled diatoms. Absorption efficiencies of participate elemental Se were 22%, when the animals were fed 75Se-labeled sediments in which elemental Se was precipitated by microbial dissimilatory reduction. Precipitation of elemental Se did not eliminate biological availability of the element. Selenite was taken up from solution slowly by M. balthica (mean concentration factor was 712). Concentrations of selenite high enough to influence Se bioaccumulation by M. balthica did not occur in the oxidized water column of San Francisco Bay. However, 98-99% of the Se observed in M. balthica could be explained by ingestion of the concentrations of participate Se found in the bay. The potential for adverse biological effects occurred at much lower concentrations of environmental Se when food web transfer was considered than when predictions of effects were based upon bioassays with solute forms of the element. Selenium clearly requires a protective criterion based upon particulate concentrations or food web transfer. ?? 1992 American Chemical Society.

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

    USDA-ARS?s Scientific Manuscript database

    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...

  8. Does boiling affect the bioaccessibility of selenium from cabbage?

    PubMed

    Funes-Collado, Virginia; Rubio, Roser; López-Sánchez, J Fermín

    2015-08-15

    The bioaccessible selenium species from cabbage were studied using an in vitro physiologically-based extraction test (PBET) which establishes conditions that simulate the gastric and gastrointestinal phases of human digestion. Samples of cabbage (Brassica oleracea) grown in peat fortified with different concentrations of Se(IV) and Se(VI) were analysed, and several enzymes (pepsin, pancreatin and amylase) were used in the PBET. The effect of boiling before extraction was also assayed. Selenium speciation in the PBET extracts was determined using anionic exchange and LC-ICP/MS. The selenocompounds in the extracts were Se(IV), SeMet and, mostly, Se(VI) species. The results show that the activity of the enzymes increased the concentration of the selenocompounds slightly, although the use of amylase had no effect on the results. The PBET showed the concentration of inorganic selenium in the extracts from boiled cabbage decreased as much as 4-fold while the release of SeMet and its concentration increased (up to 6-fold), with respect to raw cabbage.

  9. Bioavailability assessment of thiacloprid in soil as affected by biochar.

    PubMed

    Li, Yao; Zhu, Yulong; Liu, Xingang; Wu, Xiaohu; Dong, Fengshou; Xu, Jun; Zheng, Yongquan

    2017-03-01

    Biochars can significantly sorb pesticides, and reduce their bioavailability in agricultural soils. In this study, the effects of a type of biochar (BC500) on the sorption, degradation, bioaccumulation and bioavailability of thiacloprid, which is a commonly used insecticide, were investigated. The thiacloprid sorption constant (Kf values) increased by 14 times after 2% BC500 application, and the degradation of the insecticide decreased with increasing amounts of the biochars in the soil. Coupled with the exhaustive extraction and single-point Tenax method, the bioavailability of thiacloprid was predicted in the presence of the biochar. In soils amended with BC500, the thiacloprid concentrations accumulated in Tenax correlated well with those observed in earthworms (R(2) = 0.887), whereas the concentrations extracted by exhaustive method followed a less significant relationship with those in earthworms (R(2) = 0.624). The results of Tenax extractions and earthworm bioassays indicate that biochar reduces the bioavailability of thiacloprid in soil, but the delayed degradation and increased earthworm accumulation in aged biochar-amended soil imply that the environmental risks of biochar application to earthworms remain.

  10. Choice feeding of selenium-deficient laying hens affects diet selection, selenium intake and body weight.

    PubMed

    Zuberbuehler, Christine A; Messikommer, Ruth E; Wenk, Caspar

    2002-11-01

    Inadequate selenium (Se) supply often in combination with low vitamin E status causes deficiency symptoms in many species. It is likely that a vague discomfort or sickness is perceived before clear deficiency signs become apparent. We investigated whether Se-deficient hens reduce their Se deficit by selecting a diet containing more selenium when offered two diets with different Se concentrations. A Low-Se diet (0.07 mg Se/kg) was supplemented with Se-enriched yeast (Sel-Plex 50) to produce Medium-Se (0.20 mg Se/kg) and High-Se (1.50 mg Se/kg) diets. Each of two consecutive study parts (I and II) with the same hens and treatments began with a 6-wk baseline period (Medium-Se diet), subsequently followed a 9-wk depletion period (Low-Se diet or Medium-Se diet), then a 6-wk choice feeding period in which two diets with different Se concentrations (Low-Se and Medium-Se, Medium-Se and High-Se, or Low-Se and High-Se) were offered. A control group received the Medium-Se diet throughout the study. Daily Se intake, calculated from daily feed intake, followed similar patterns in both parts of the study, but Se-deficient hens preferred (P < 0.05) the High-Se diet to the Low-Se diet during the first 3 wk of choice feeding only in part I. We conclude that young Se-deficient laying hens reduce their Se deficit if they have a choice between a Low-Se and a High-Se diet by preferentially selecting the High-Se diet, possibly based on learned place preference and/or learned taste aversion to the Low-Se diet, presumably in response to discomfort due to Se-deficiency.

  11. 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.

  12. Food microstructure affects the bioavailability of several nutrients.

    PubMed

    Parada, J; Aguilera, J M

    2007-03-01

    There is an increased interest in the role that some nutrients may play in preventing or ameliorating the effect of major diseases (for example, some types of cancer, cardiovascular diseases, eye disorders, among others). In this respect, the bioavailability or the proportion of an ingested nutrient that is made available (that is, delivered to the bloodstream) for its intended mode of action is more relevant than the total amount present in the original food. Disruption of the natural matrix or the microstructure created during processing may influence the release, transformation, and subsequent absorption of some nutrients in the digestive tract. Alternatively, extracts of bioactive molecules (for example, nutraceuticals) and beneficial microorganisms may be protected during their transit in the digestive system to the absorption sites by encapsulation in designed matrices. This review summarizes relevant in vivo and in vitro methods used to assess the bioavailability of some nutrients (mostly phytochemicals), types of microstructural changes imparted by processing and during food ingestion that are relevant in matrix-nutrient interactions, and their effect on the bioavailability of selected nutrients.

  13. Selenium supplementation does not affect testicular selenium status or semen quality in North American men.

    PubMed

    Hawkes, Wayne Chris; Alkan, Zeynep; Wong, Kenneth

    2009-01-01

    Selenium (Se) is essential for sperm function and male fertility, but high Se intake has been associated with impaired semen quality. We reported previously a decrease in sperm motility in men fed high-Se foods, but we could not rule out the influence of other environmental and dietary factors. We now report on a randomized, controlled study on the potential adverse effects of Se supplementation on semen quality in 42 free-living men administered Se (300 microg/d) as high-Se yeast for 48 weeks. Semen analysis was performed 4 times before treatment began, then twice each week during treatment at 6, 12, 24, 36, and 48 weeks, and then after treatment at 72 and 96 weeks. Blood samples were collected 3 times before treatment and at each subsequent visit. Se concentration increased 61% in blood plasma and 49% in seminal plasma. However, Se supplementation had no effect on sperm Se, serum androgen concentrations, or sperm count, motility, progressive velocity, or morphology. We observed progressive decreases in serum luteinizing hormone, semen volume, and sperm Se in both the high-Se and placebo groups. Moreover, sperm straight-line velocity and percent normal morphology increased in Se-treated and placebo-treated participants. The lack of an increase in sperm Se suggests that testicular Se stores were unaffected, even though the participants' dietary Se intake was tripled and their total body Se approximately doubled by supplementation. These results are consistent with animal studies showing the Se status of testes to be unresponsive to dietary Se intake.

  14. Genetic polymorphisms that affect selenium status and response to selenium supplementation in United Kingdom pregnant women1

    PubMed Central

    Mao, Jinyuan; Vanderlelie, Jessica J; Perkins, Anthony V; Redman, Christopher WG; Ahmadi, Kourosh R; Rayman, Margaret P

    2016-01-01

    Background: Low selenium status in pregnancy has been associated with a number of adverse conditions. In nonpregnant populations, the selenium status or response to supplementation has been associated with polymorphisms in dimethylglycine dehydrogenase (DMGDH), selenoprotein P (SEPP1) and the glutathione peroxidases [cytosolic glutathione peroxidase (GPx1) and phospholipid glutathione peroxidase (GPx4)]. Objective: We hypothesized that, in pregnant women, these candidate polymorphisms would be associated with selenium status in early pregnancy, its longitudinal change, and the interindividual response to selenium supplementation at 60 μg/d. Design: With the use of stored samples and data from the United Kingdom Selenium in Pregnancy Intervention (SPRINT) study in 227 pregnant women, we carried out genetic-association studies, testing for associations between selenium status, its longitudinal change, and response to supplementation and common genetic variation in DMGDH (rs921943), SEPP1 (rs3877899 and rs7579), GPx1 (rs1050450) and GPx4 (rs713041). Selenium status was represented by the concentration of whole-blood selenium at 12 and 35 wk of gestation, the concentration of toenail selenium at 16 wk of gestation, and plasma glutathione peroxidase (GPx3) activity at 12 and 35 wk of gestation. Results: Our results showed that DMGDH rs921943 was significantly associated with the whole-blood selenium concentration at 12 wk of gestation (P = 0.032), which explained ≤2.0% of the variance. This association was replicated with the use of toenail selenium (P = 0.043). In unsupplemented women, SEPP1 rs3877899 was significantly associated with the percentage change in whole-blood selenium from 12 to 35 wk of gestation (P = 0.005), which explained 8% of the variance. In supplemented women, SEPP1 rs3877899 was significantly associated with the percentage change in GPx3 activity from 12 to 35 wk of gestation (P = 0.01), which explained 5.3% of the variance. Selenium status was

  15. Interactions between active pharmaceutical ingredients and excipients affecting bioavailability: impact on bioequivalence.

    PubMed

    García-Arieta, Alfredo

    2014-12-18

    The aim of the present paper is to illustrate the impact that excipients may have on the bioavailability of drugs and to review existing US-FDA, WHO and EMA regulatory guidelines on this topic. The first examples illustrate that small amounts of sorbitol (7, 50 or 60mg) affect the bioavailability of risperidone, a class I drug, oral solution, in contrast to what is stated in the US-FDA guidance. Another example suggests, in contrast to what is stated in the US-FDA BCS biowaivers guideline, that a small amount of sodium lauryl sulphate (SLS) (3.64mg) affects the bioavailability of risperidone tablets, although the reference product also includes SLS in an amount within the normal range for that type of dosage form. These factors are considered sufficient to ensure that excipients do not affect bioavailability according to the WHO guideline. The alternative criterion, defined in the WHO guideline and used in the FIP BCS biowaivers monographs, that asserts that excipients present in generic products of the ICH countries do not affect bioavailability if used in normal amounts, is shown to be incorrect with an example of alendronate (a class III drug) tablets, where 4mg of SLS increases bioavailability more than 5-fold, although a generic product in the USA contains SLS. Finally, another example illustrates that a 2mg difference in SLS may affect bioavailability of a generic product of a class II drug, even if SLS is contained in the comparator product, and in all cases its amount was within the normal range. Therefore, waivers of in vivo bioequivalence studies (e.g., BCS biowaivers, waivers of certain dosage forms in solution at the time of administration and variations in the excipient composition) should be assessed more cautiously.

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

    PubMed

    Zeng, Huawei; Jackson, Matthew I; Cheng, Wen-Hsing; Combs, Gerald F

    2011-11-01

    Determining the effect of selenium (Se) chemical form on uptake, transport, and glutathione peroxidase activity in human intestinal cells is critical to assess Se bioavailability at nutritional doses. In this study, we found that two sources of L-selenomethionine (SeMet) and Se-enriched yeast each increased intracellular Se content more effectively than selenite or methylselenocysteine (SeMSC) in the human intestinal Caco-2 cell model. Interestingly, SeMSC, SeMet, and digested Se-enriched yeast were transported at comparable efficacy from the apical to basolateral sides, each being about 3-fold that of selenite. In addition, these forms of Se, whether before or after traversing from apical side to basolateral side, did not change the potential to support glutathione peroxidase (GPx) activity. Although selenoprotein P has been postulated to be a key Se transport protein, its intracellular expression did not differ when selenite, SeMSC, SeMet, or digested Se-enriched yeast was added to serum-contained media. Taken together, our data show, for the first time, that the chemical form of Se at nutritional doses can affect the absorptive (apical to basolateral side) efficacy and retention of Se by intestinal cells; but that, these effects are not directly correlated to the potential to support GPx activity.

  17. Assessment of bioavailability of selenium in different plant-soil systems by diffusive gradients in thin-films (DGT).

    PubMed

    Peng, Qin; Wang, Mengke; Cui, Zewei; Huang, Jie; Chen, Changer; Guo, Lu; Liang, Dongli

    2017-03-21

    Uptake of selenium (Se) by plants largely depend on the availability of Se in soil. Soils and plants were sampled four times within 8 weeks of plant growth in pot experiments using four plant species. Sequential extraction and diffusive gradients in thin-films (DGT) method were employed to measure Se concentrations in potted soils in selenite- or selenate-amended soils. Results showed that DGT-measured Se concentrations (CDGT-Se) were generally several folds higher for selenate than selenite amended soils, which were obviously affected by the plant species and the duration of their growth. For example, the folds in soil planted with mustard were 1.49-3.47 and those in soils planted with purple cabbage and broccoli, which grew for 3 and 4 weeks after sowing, were 1.06-2.14 and only 0.15-0.62 after 6 weeks of growth. The selenate-amended soil planted with wheat showed an extremely high CDGT-Se compared with selenite-amended soil, except the last harvest. Furthermore, minimal changes in CDGT-Se and soluble Se(IV) were found in selenite-amended soils during plant growth, whereas significant changes were observed in selenate-amended soils (p < 0.05). Additionally, Se distribution in various fractions of soil remarkably changed; the soils planted with purple cabbage and broccoli showed the most obvious change followed by wheat and mustard. Soluble Se(VI) and exchangeable Se(VI) were likely the major sources of CDGT-Se in selenate-amended soils, and soluble Se(IV) was the possible source of CDGT-Se in selenite-amended soils. In selenate-amended soils, soluble Se(VI) and exchangeable Se(VI) were significantly correlated with Se concentrations in purple cabbage, broccoli, and mustard; in wheat, Se concentration was significantly correlated only with soluble Se(VI) but not with exchangeable Se. CDGT-Se eventually became positively correlated with Se concentrations accumulated by different plants, indicating that DGT is a feasible method in predicting plant uptake of

  18. Selenium supplementation affects broiler growth performance, meat yield and feather coverage.

    PubMed

    Choct, M; Naylor, A J; Reinke, N

    2004-10-01

    (1) Selenium (Se) is an essential part of numerous selenoproteins, most of which are involved in the antioxidant system of the body. It is also required by poultry for the maintenance of optimal health and meat quality. This paper reports data from a study examining the effect of dietary source and concentration of selenium on broiler performance and meat quality. (2) Increased dietary selenium content markedly reduced feed conversion ratio (FCR) as a result of significantly lower feed intakes of birds while maintaining the same weight gains. (3) Selenium supplementation increased feathering, with organic selenium (selenised yeast) being superior to inorganic selenium (sodium selenite). (4) Birds receiving organic selenium in their diets had improved eviscerated weight, breast yield and reduced drip loss. (5) There were significant concentration x source interactions on yields of breasts and marylands (thigh plus drumstick), with elevated levels of organic selenium increasing the yields, whereas the opposite was true for the inorganic selenium.

  19. 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.

  20. A dietary assessment of selenium risk to aquatic birds on a coal mine affected stream in Alberta, Canada

    SciTech Connect

    Wayland, M.; Casey, R.; Woodsworth, E.

    2007-07-15

    In this article, we present the results of a dietary-based assessment of the risk that selenium may pose to two aquatic bird species, the American Dipper (Cinclus mexicanus) and the Harlequin Duck (Histrionicus histrionicus), on one of the coal mine-affected streams, the Gregg River. The study consisted of (1) a literature-based toxicity assessment, (2) simulation of selenium exposure in the diets and eggs of the two species, and (3) a risk assessment that coupled information on toxicity and exposure. Diet and egg selenium concentrations associated with a 20% hatch failure rate were 6.4 and 17 {mu} g {center_dot} g{sup -1} dry wt, respectively. Simulated dietary selenium concentrations were about 2.0-2.5 {mu} g {center_dot} g{sup -1} higher on the Gregg River than on reference streams for both species. When simulated dietary concentrations were considered, hatch failure rates on the Gregg River were predicted to average 12% higher in American Dippers and 8% higher in Harlequin Ducks than at reference streams. Corresponding values were only 3% for both species when predicted egg concentrations were used. Elevated levels of selenium in insects in some of the reference streams were unexpected and raised a question as to whether aquatic birds have evolved a higher tolerance level for dietary selenium in these areas.

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

    PubMed Central

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

    2012-01-01

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

  2. Transcriptomics and proteomics show that selenium affects inflammation, cytoskeleton, and cancer pathways in human rectal biopsies.

    PubMed

    Méplan, Catherine; Johnson, Ian T; Polley, Abigael C J; Cockell, Simon; Bradburn, David M; Commane, Daniel M; Arasaradnam, Ramesh P; Mulholland, Francis; Zupanic, Anze; Mathers, John C; Hesketh, John

    2016-08-01

    Epidemiologic studies highlight the potential role of dietary selenium (Se) in colorectal cancer prevention. Our goal was to elucidate whether expression of factors crucial for colorectal homoeostasis is affected by physiologic differences in Se status. Using transcriptomics and proteomics followed by pathway analysis, we identified pathways affected by Se status in rectal biopsies from 22 healthy adults, including 11 controls with optimal status (mean plasma Se = 1.43 μM) and 11 subjects with suboptimal status (mean plasma Se = 0.86 μM). We observed that 254 genes and 26 proteins implicated in cancer (80%), immune function and inflammatory response (40%), cell growth and proliferation (70%), cellular movement, and cell death (50%) were differentially expressed between the 2 groups. Expression of 69 genes, including selenoproteins W1 and K, which are genes involved in cytoskeleton remodelling and transcription factor NFκB signaling, correlated significantly with Se status. Integrating proteomics and transcriptomics datasets revealed reduced inflammatory and immune responses and cytoskeleton remodelling in the suboptimal Se status group. This is the first study combining omics technologies to describe the impact of differences in Se status on colorectal expression patterns, revealing that suboptimal Se status could alter inflammatory signaling and cytoskeleton in human rectal mucosa and so influence cancer risk.-Méplan, C., Johnson, I. T., Polley, A. C. J., Cockell, S., Bradburn, D. M., Commane, D. M., Arasaradnam, R. P., Mulholland, F., Zupanic, A., Mathers, J. C., Hesketh, J. Transcriptomics and proteomics show that selenium affects inflammation, cytoskeleton, and cancer pathways in human rectal biopsies. © The Author(s).

  3. A short-term intervention with selenium affects expression of genes implicated in the epithelial-to-mesenchymal transition in the prostate

    PubMed Central

    Kok, Dieuwertje E.G.; Kiemeney, Lambertus A.L.M.; Verhaegh, Gerald W.; Schalken, Jack A.; van Lin, Emile N.J.T.; Michiel Sedelaar, J.P.; Alfred Witjes, J.; Hulsbergen - van de Kaa, Christina A.; van't Veer, Pieter; Kampman, Ellen; Afman, Lydia A.

    2017-01-01

    In parallel with the inconsistency in observational studies and chemoprevention trials, the mechanisms by which selenium affects prostate cancer risk have not been elucidated. We conducted a randomized, placebo-controlled trial to examine the effects of a short-term intervention with selenium on gene expression in non-malignant prostate tissue. Twenty-three men received 300 μg selenium per day in the form of selenized yeast (n=12) or a placebo (n=11) during 5 weeks. Prostate biopsies collected from the transition zone before and after intervention were analysed for 15 participants (n=8 selenium, n=7 placebo). Pathway analyses revealed that the intervention with selenium was associated with down-regulated expression of genes involved in cellular migration, invasion, remodeling and immune responses. Specifically, expression of well-established epithelial markers, such as E-cadherin and epithelial cell adhesion molecule EPCAM, was up-regulated, while the mesenchymal markers vimentin and fibronectin were down-regulated after intervention with selenium. This implies an inhibitory effect of selenium on the epithelial-to-mesenchymal transition (EMT). Moreover, selenium was associated with down-regulated expression of genes involved in wound healing and inflammation; processes which are both related to EMT. In conclusion, our explorative data showed that selenium affected expression of genes implicated in EMT in the transition zone of the prostate. PMID:28076331

  4. A short-term intervention with selenium affects expression of genes implicated in the epithelial-to-mesenchymal transition in the prostate.

    PubMed

    Kok, Dieuwertje E G; Kiemeney, Lambertus A L M; Verhaegh, Gerald W; Schalken, Jack A; van Lin, Emile N J T; Sedelaar, J P Michiel; Witjes, J Alfred; Hulsbergen-van de Kaa, Christina A; van 't Veer, Pieter; Kampman, Ellen; Afman, Lydia A

    2017-02-07

    In parallel with the inconsistency in observational studies and chemoprevention trials, the mechanisms by which selenium affects prostate cancer risk have not been elucidated. We conducted a randomized, placebo-controlled trial to examine the effects of a short-term intervention with selenium on gene expression in non-malignant prostate tissue. Twenty-three men received 300 µg selenium per day in the form of selenized yeast (n=12) or a placebo (n=11) during 5 weeks. Prostate biopsies collected from the transition zone before and after intervention were analysed for 15 participants (n=8 selenium, n=7 placebo). Pathway analyses revealed that the intervention with selenium was associated with down-regulated expression of genes involved in cellular migration, invasion, remodeling and immune responses. Specifically, expression of well-established epithelial markers, such as E-cadherin and epithelial cell adhesion molecule EPCAM, was up-regulated, while the mesenchymal markers vimentin and fibronectin were down-regulated after intervention with selenium. This implies an inhibitory effect of selenium on the epithelial-to-mesenchymal transition (EMT). Moreover, selenium was associated with down-regulated expression of genes involved in wound healing and inflammation; processes which are both related to EMT. In conclusion, our explorative data showed that selenium affected expression of genes implicated in EMT in the transition zone of the prostate.

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

    NASA Astrophysics Data System (ADS)

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

    2017-09-01

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

  6. Processes affecting the distribution of selenium in shallow ground water of agricultural areas, western San Joaquin Valley, California

    USGS Publications Warehouse

    Deverel, S.J.; Fujii, Roger

    1987-01-01

    A study was undertaken to evaluate the processes affecting the chemistry of shallow groundwater associated with agricultural drainage systems in the western San Joaquin Valley, California. The study was prompted by a need for an understanding of selenium mobility in areas having high selenium concentrations in shallow groundwater. Groundwater samples were collected along transects in three artificially drained fields where the age of the drainage system varied (15, 6, and 1.5 years). Selenium concentrations in the drainage water also varied (430, 58, and 3700 mg/L, respectively). Isotopic enrichment and chemical composition of the groundwater samples indicate that saline- and selenium- enriched water has evolved as a result of evaporation of groundwater. This evaporated, isotopically enriched water is being displaced by more recent, less saline irrigation water percolating through the root zone. This placement seems to be a process in which sodium chloride and sodium sulfate water is being replaced by more dilute calcium sulfate and calcium bicarbonate water. (Author 's abstract)

  7. Processes affecting the distribution of selenium in shallow groundwater of agricultural areas, western San Joaquin Valley, California

    USGS Publications Warehouse

    Deverel, S.J.; Fujii, R.

    1988-01-01

    A study was undertaken to evaluate the processes affecting the chemistry of shallow groundwater associated with agricultural drainage systems in the western San Joaquin Valley, California. The study was prompted by a need for an understanding of selenium mobility in areas having high selenium concentrations in shallow groundwater. Groundwater samples were collected along transects in three artificially drained fields where the age of the drainage system varied (15, 6, and 1.5 years). Selenium concentrations in the drain water also varied (430, 58, and 3700 μg/L, respectively). Isotopic enrichment and chemical composition of the groundwater samples indicate that saline- and selenium-enriched water has evolved as a result of evaporation or transpiration of groundwater. This evaporated, isotopically enriched water is being displaced by more recent, less saline irrigation water percolating through the root zone. This displacement seems to be a process whereby sodium chloride and sodium sulfate water is being replaced by more dilute calcium sulfate and calcium bicarbonate water.

  8. Higher whole-blood selenium is associated with improved immune responses in footrot-affected sheep

    PubMed Central

    2011-01-01

    We reported previously that sheep affected with footrot (FR) have lower whole-blood selenium (WB-Se) concentrations and that parenteral Se-supplementation in conjunction with routine control practices accelerates recovery from FR. The purpose of this follow-up study was to investigate the mechanisms by which Se facilitates recovery from FR. Sheep affected with FR (n = 38) were injected monthly for 15 months with either 5 mg Se (FR-Se) or saline (FR-Sal), whereas 19 healthy sheep received no treatment. Adaptive immune function was evaluated after 3 months of Se supplementation by immunizing all sheep with a novel protein, keyhole limpet hemocyanin (KLH). The antibody titer and delayed-type hypersensitivity (DTH) skin test to KLH were used to assess humoral immunity and cell-mediated immunity, respectively. Innate immunity was evaluated after 3 months of Se supplementation by measuring intradermal responses to histamine 30 min after injection compared to KLH and saline, and after 15 months of Se supplementation by isolating neutrophils and measuring their bacterial killing ability and relative abundance of mRNA for genes associated with neutrophil migration. Compared to healthy sheep, immune responses to a novel protein were suppressed in FR-affected sheep with smaller decreases in FR-affected sheep that received Se or had WB-Se concentrations above 250 ng/mL at the time of the immune assays. Neutrophil function was suppressed in FR-affected sheep, but was not changed by Se supplementation or WB-Se status. Sheep FR is associated with depressed immune responses to a novel protein, which may be partly restored by improving WB-Se status (> 250 ng/mL). PMID:21896161

  9. Selenium Supplementation Restores Innate and Humoral Immune Responses in Footrot-Affected Sheep

    PubMed Central

    Hall, Jean A.; Vorachek, William R.; Stewart, Whitney C.; Gorman, M. Elena; Mosher, Wayne D.; Pirelli, Gene J.; Bobe, Gerd

    2013-01-01

    Dietary selenium (Se) alters whole-blood Se concentrations in sheep, dependent upon Se source and dosage administered, but little is known about effects on immune function. We used footrot (FR) as a disease model to test the effects of supranutritional Se supplementation on immune function. To determine the effect of Se-source (organic Se-yeast, inorganic Na-selenite or Na-selenate) and Se-dosage (1, 3, 5 times FDA-permitted level) on FR severity, 120 ewes with and 120 ewes without FR were drenched weekly for 62 weeks with different Se sources and dosages (30 ewes/treatment group). Innate immunity was evaluated after 62 weeks of supplementation by measuring neutrophil bacterial killing ability. Adaptive immune function was evaluated by immunizing sheep with keyhole limpet hemocyanin (KLH). The antibody titer and delayed-type hypersensitivity skin test to KLH were used to assess humoral immunity and cell-mediated immunity, respectively. At baseline, FR-affected ewes had lower whole-blood and serum-Se concentrations; this difference was not observed after Se supplementation. Se supplementation increased neutrophil bacterial killing percentages in FR-affected sheep to percentages observed in supplemented and non-supplemented healthy sheep. Similarly, Se supplementation increased KLH antibody titers in FR-affected sheep to titers observed in healthy sheep. FR-affected sheep demonstrated suppressed cell-mediated immunity at 24 hours after intradermal KLH challenge, although there was no improvement with Se supplementation. We did not consistently prevent nor improve recovery from FR over the 62 week Se-treatment period. In conclusion, Se supplementation does not prevent FR, but does restore innate and humoral immune functions negatively affected by FR. PMID:24340044

  10. Anatomical, physiological and experimental factors affecting the bioavailability of sc administered large biotherapeutics

    PubMed Central

    Fathallah, Anas M.; Balu-Iyer, Sathy V.

    2014-01-01

    Subcutaneous route of administration is highly desirable for protein therapeutics. It improves patient compliance and quality of life1,2, while reducing healthcare cost2. Recent evidence also suggests that sc administration of protein therapeutics can increase tolerability to some treatments such as intravenous immunoglobulin therapy (IVIG) by administering it subcutaneously (subcutaneous immunoglobulin therapy SCIG), which will reduce fluctuation in plasma drug concentration3. Furthermore, sc administration may reduce the risk of systemic infections associated with iv infusion1,2. This route, however, has its challenges especially for large multi-domain proteins. Poor bioavailability and poor scalability from preclinical models are often cited. This commentary will discuss barriers to sc absorption as well as physiological and experimental factors that could affect pharmacokinetics of subcutaneously administered large protein therapeutics in preclinical models. A mechanistic pharmacokinetic model is proposed as a potential tool to address the issue of scalability of sc pharmacokinetic from preclinical models to humans PMID:25411114

  11. The addition of milk or yogurt to a plant-based diet increases zinc bioavailability but does not affect iron bioavailability in women.

    PubMed

    Rosado, Jorge L; Díaz, Margarita; González, Karla; Griffin, Ian; Abrams, Steven A; Preciado, Roxana

    2005-03-01

    The addition of milk and milk-based products to the diets of individuals subsisting on plant-based diets was reported to have positive effects on nutritional status and functional outcomes such as growth, morbidity, and cognition. We examined the effect of the addition of milk or yogurt on the bioavailability of zinc and iron from a plant-based rural diet. The subjects were 48 Mexican women (30.9 +/- 5.7 y) who habitually consumed a plant-based diet. The women were assigned to 1 of 3 groups: 1) the typical rural Mexican diet, 2) that diet with milk added, or 3) that diet with yogurt for 13 d. Zinc absorption was measured after extrinsically labeling meals with (67)Zn and an i.v. dose of (70)Zn; iron absorption was measured by extrinsically labeling meals with (58)Fe and a reference oral dose of (57)Fe. Including milk and yogurt in the diet increased zinc absorption by 50 and 68%, respectively (P < 0.05). The 3 groups did not differ in the percentage iron absorption. The total amount of zinc absorbed was increased (P < 0.05) by 70% when milk was added to the meal and 78% when yogurt was added. The total amount of iron absorbed did not differ among the groups. The addition of milk and yogurt to a plant-based diet high in phytate increases zinc bioavailability without affecting iron bioavailability.

  12. Food web pathway determines how selenium affects aquatic ecosystems: A San francisco Bay case study

    USGS Publications Warehouse

    Stewart, A.R.; Luoma, S.N.; Schlekat, C.E.; Doblin, M.A.; Hieb, K.A.

    2004-01-01

    Chemical contaminants disrupt ecosystems, but specific effects may be under-appreciated when poorly known processes such as uptake mechanisms, uptake via diet, food preferences, and food web dynamics are influential. Here we show that a combination of food web structure and the physiology of trace element accumulation explain why some species in San Francisco Bay are threatened by a relatively low level of selenium contamination and some are not. Bivalves and crustacean Zooplankton form the base of two dominant food webs in estuaries. The dominant bivalve Potamocorbula amurensis has a 10-fold slower rate constant of loss for selenium than do common crustaceans such as copepods and the mysid Neomysis mercedis (rate constant of loss, ke = 0.025, 0.155, and 0.25 d-1, respectively). The result is much higher selenium concentrations in the bivalve than in the crustaceans. Stable isotope analyses show that this difference is propagated up the respective food webs in San Francisco Bay. Several predators of bivalves have tissue concentrations of selenium that exceed thresholds thought to be associated with teratogenesis or reproductive failure (liver Se > 15 ??g g-1 dry weight). Deformities typical of selenium-induced teratogenesis were observed in one of these species. Concentrations of selenium in tissues of predators of Zooplankton are less than the thresholds. Basic physiological and ecological processes can drive wide differences in exposure and effects among species, but such processes are rarely considered in traditional evaluations of contaminant impacts.

  13. Selenium affects the expression of GPx4 and catalase in the liver of chicken.

    PubMed

    Zoidis, E; Pappas, A C; Georgiou, C A; Komaitis, Epsilon; Feggeros, K

    2010-03-01

    A total of 128 chickens (Gallus gallus, broilers) were used to investigate the effect of organic selenium (Se) in expression of catalase (CAT) and phospholipid hydroperoxidase 4 (GPx4) genes. There were 4 replicates of 4 dietary treatments: T1 (basal diet with no added Se), T2 (T1 with 0.15 ppm Se added), T3 (T1 with 0.3 ppm Se) and T4 (T1 with 3.0 ppm Se). At 4th and 6th week, 2 chickens per replicate pen were sacrificed for whole blood and liver sample collections. Samples were analyzed for total Se by ICP-MS and gene expression by RT-PCR. Dietary supplementation with organic Se (Se-yeast) readily elevated its concentration in the tissues. GPx4 mRNA levels, pooled for both ages, of chickens fed T3 and T4 diets were significantly reduced compared to those fed diet T1 by 47% and 77% respectively, while that of T2 did not differ. Liver CAT mRNA levels at 4th week were significantly decreased as Se supplementation increased, while at 6th week, were not significantly affected by Se. The study showed that liver GPx4 mRNA levels could be down-regulated by excess of Se. It is possible that reserves built by excess of Se meet antioxidant requirements and no additional GPx4 transcription is necessary. 2009 Elsevier Inc. All rights reserved.

  14. Assessment of intake of iron and nutrients that affect bioavailability of daily food rations of girls.

    PubMed

    Broniecka, Anna; Wyka, Joanna; Bronkowska, Monika; Piotrowska, Ewa; Biernat, Jadwiga

    2014-01-01

    In a human body iron occurs at a level of 3 to 5 g, 60-70 % of which are in hemoglobin, ca. 10% in myoglobin, and ca. 3% are accumulated in enzymes of cellular respiration or enzymes degrading toxic hydrogen peroxide. The other part of iron is accumulated in liver, spleen, kidneys and bone marrow. The dietary deficiency of iron appears at its insufficient level in a diet and at impaired absorption of iron ions present in food products by a body. Groups at an especially high risk of iron deficiencies include, among others, menstruating girls in the pubescence period and women with heavy and irregular menstruations, as well as vegetarians and patients with chronic enteritis. To evaluate the intake of iron and nutrients that affect its bioavailability from daily food rations of girls. The study included 159 girls aged 17-18, students of high schools in the city of Wroclaw. The study was conducted between November 2010 and ay 2011. Girls were divided into 3 subgroups according to the BMI score. Girls' diets were analyzed with the method of a direct interview of the last 24 hours before the test and the interview was repeated seven times. RESULTS The present study demonstrated that the intake of iron from food rations of almost all the girls surveyed was below the requirements defined for this age group. Statistically significant differences were noted in the intake of energy and nutrients among the three distinguished subgroups of girls. CONCLUSIONS Food rations of the surveyed girls were characterized by a low, compared to dietary allowances, calorific value, which resulted in deficiencies of nutrients increasing iron bioavailability.

  15. In vitro selenium accessibility in pet foods is affected by diet composition and type.

    PubMed

    van Zelst, Mariëlle; Hesta, Myriam; Alexander, Lucille G; Gray, Kerry; Bosch, Guido; Hendriks, Wouter H; Du Laing, Gijs; De Meulenaer, Bruno; Goethals, Klara; Janssens, Geert P J

    2015-06-28

    Se bioavailability in commercial pet foods has been shown to be highly variable. The aim of the present study was to identify dietary factors associated with in vitro accessibility of Se (Se Aiv) in pet foods. Se Aiv is defined as the percentage of Se from the diet that is potentially available for absorption after in vitro digestion. Sixty-two diets (dog, n 52; cat, n 10) were in vitro enzymatically digested: fifty-four of them were commercially available (kibble, n 20; pellet, n 8; canned, n 17; raw meat, n 6; steamed meat, n 3) and eight were unprocessed (kibble, n 4; canned, n 4) from the same batch as the corresponding processed diets. The present investigation examined if Se Aiv was affected by diet type, dietary protein, methionine, cysteine, lysine and Se content, DM, organic matter and crude protein (CP) digestibility. Se Aiv differed significantly among diet types (P< 0·001). Canned and steamed meat diets had a lower Se Aiv than pelleted and raw meat diets. Se Aiv correlated positively with CP digestibility in extruded diets (kibbles, n 19; r 0·540, P =0·017) and negatively in canned diets (n 16; r - 0·611, P =0·012). Moreover, the canning process (n 4) decreased Se Aiv (P =0·001), whereas extrusion (n 4) revealed no effect on Se Aiv (P =0·297). These differences in Se Aiv between diet types warrant quantification of diet type effects on in vivo Se bioavailability.

  16. Levels of plasma selenium and urinary total arsenic interact to affect the risk for prostate cancer.

    PubMed

    Hsueh, Yu-Mei; Su, Chien-Tien; Shiue, Horng-Sheng; Chen, Wei-Jen; Pu, Yeong-Shiau; Lin, Ying-Chin; Tsai, Cheng-Shiuan; Huang, Chao-Yuan

    2017-09-01

    This study investigated whether plasma selenium levels modified the risk for prostate cancer (PC) related to arsenic exposure. We conducted a case-control study that included 318 PC patients and 318 age-matched, healthy control subjects. Urinary arsenic profiles were examined using HPLC-HG-AAS and plasma selenium levels were measured by ICP-MS. We found that plasma selenium levels displayed a significant dose-dependent inverse association with PC. The odds ratio (OR) and 95% confidence interval (CI) for PC was 0.07 (0.04-0.13) among participants with a plasma selenium level >28.06 μg/dL vs. ≤19.13 μg/dL. A multivariate analysis showed that participants with a urinary total arsenic concentration >29.28 μg/L had a significantly higher OR (1.75, 1.06-2.89) for PC than participants with ≤29.89 μg/L. The combined presence of a low plasma selenium level and a high urinary total arsenic concentration exponentially increased the OR for PC, and additively interacted with PSA at levels ≥20 ng/mL. This is the first epidemiological study to examine the combined effects of plasma selenium and urinary total arsenic levels on the OR for PC. Our data suggest a low plasma selenium level coupled with a high urinary total arsenic concentration creates a significant risk for aggressive PC. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. Selenium in San Francisco Bay - 30 Years of Surprises

    NASA Astrophysics Data System (ADS)

    Cutter, G. A.

    2015-12-01

    The trace element selenium exists in multiple oxidation states (VI, IV, 0, -II) and chemical forms within an oxidation state, and this chemical speciation affects its bio-availability and geochemical cycling. The interactions between the physical circulation and riverine inputs, changing ecosystem components, and industrial inputs to the San Francisco Bay have had profound and surprising influences on the biogeochemical behavior of selenium in this estuary. In the mid-1980s dissolved selenium was relatively elevated and enriched in selenite (SeIV) in the mid-estuary, occurrences that were quantitatively linked to inputs from oil refinery effluents. Suspended particulate selenium concentrations were at a level considered problematic for filter feeding clams with high assimilation efficiencies. By 1999 oil refineries had implemented selenium removal processes that dramatically dropped the concentrations of total dissolved selenium and selenite by over 65% in the estuarine water column. Surprisingly, the concentrations of selenium in suspended particles did not drop as dramatically. We suspect that changes in the ecosystem, including the abundance of certain phytoplankton species and changes in benthic grazing affect the abundance of selenium in suspended particles. These and other changes within the San Francisco Bay system have been simulated in numerical models that reveal other surprising aspects of selenium cycling in this estuary. Data and models will be discussed in this presentation, and implications for other trace elements presented.

  18. Solubility constraints affecting the migration of selenium through the cementitious backfill of a geological disposal facility.

    PubMed

    Felipe-Sotelo, M; Hinchliff, J; Evans, N D M; Read, D

    2016-03-15

    This work presents the study of the solubility of selenium under cementitious conditions and its diffusion, as SeO3(2-), through monolithic cement samples. The solubility studies were carried out under alkaline conditions similar to those anticipated in the near-field of a cement-based repository for low- and intermediate-level radioactive waste. Experiments were conducted in NaOH solution, 95%-saturated Ca(OH)2, water equilibrated with a potential backfill material (Nirex reference vault backfill, NRVB) and in solutions containing cellulose degradation products, with and without reducing agents. The highest selenium concentrations were found in NaOH solution. In the calcium-containing solutions, analysis of the precipitates suggests that the solubility controlling phase is Ca2SeO3(OH)2·2H2O, which appears as euhedral rhombic crystals. The presence of cellulose degradation products caused an increase in selenium concentration, possibly due to competitive complexation, thereby, limiting the amount of calcium available for precipitation. Iron coupons had a minor effect on selenium solubility in contrast to Na2S2O4, suggesting that effective reduction of Se(IV) occurs only at Eh values below -300mV. Radial through-diffusion experiments on NRVB and in a fly ash cement showed no evidence of selenium breakthrough after one year. However, autoradiography of the exposed surfaces indicated that some migration had occurred and that selenium was more mobile in the higher porosity backfill than in the fly ash cement.

  19. Post-weaning selenium and folate supplementation affects gene and protein expression and global DNA methylation in mice fed high-fat diets.

    PubMed

    Bermingham, Emma N; Bassett, Shalome A; Young, Wayne; Roy, Nicole C; McNabb, Warren C; Cooney, Janine M; Brewster, Di T; Laing, William A; Barnett, Matthew P G

    2013-03-05

    Consumption of high-fat diets has negative impacts on health and well-being, some of which may be epigenetically regulated. Selenium and folate are two compounds which influence epigenetic mechanisms. We investigated the hypothesis that post-weaning supplementation with adequate levels of selenium and folate in offspring of female mice fed a high-fat, low selenium and folate diet during gestation and lactation will lead to epigenetic changes of potential importance for long-term health. Female offspring of mothers fed the experimental diet were either maintained on this diet (HF-low-low), or weaned onto a high-fat diet with sufficient levels of selenium and folate (HF-low-suf), for 8 weeks. Gene and protein expression, DNA methylation, and histone modifications were measured in colon and liver of female offspring. Adequate levels of selenium and folate post-weaning affected gene expression in colon and liver of offspring, including decreasing Slc2a4 gene expression. Protein expression was only altered in the liver. There was no effect of adequate levels of selenium and folate on global histone modifications in the liver. Global liver DNA methylation was decreased in mice switched to adequate levels of selenium and folate, but there was no effect on methylation of specific CpG sites within the Slc2a4 gene in liver. Post-weaning supplementation with adequate levels of selenium and folate in female offspring of mice fed high-fat diets inadequate in selenium and folate during gestation and lactation can alter global DNA methylation in liver. This may be one factor through which the negative effects of a poor diet during early life can be ameliorated. Further research is required to establish what role epigenetic changes play in mediating observed changes in gene and protein expression, and the relevance of these changes to health.

  20. Inoculum carrier and contaminant bioavailability affect fungal degradation performances of PAH-contaminated solid matrices from a wood preservation plant.

    PubMed

    Covino, Stefano; Svobodová, Katerina; Cvancarová, Monika; D'Annibale, Alessandro; Petruccioli, Maurizio; Federici, Federico; Kresinová, Zdena; Galli, Emanuela; Cajthaml, Tomás

    2010-05-01

    The objective of the study was to investigate the impact of chopped wheat straw (CWS), ground corn cobs (GCC) and commercial pellets (CP), as inoculum carriers, on both growth and polycyclic aromatic hydrocarbons (PAH) degradation performances of Dichomitus squalens, Pleurotus ostreatus and Coprinus comatus. A historically-contaminated soil (HCS) and creosote-treated shavings (CTS) from the Sobeslav wood preservation plant, characterized by different relative abundances of the PAH bioavailable fractions, were used to assess the contaminated matrix effect and its interaction with both carrier and fungal strain. In HCS, best results were obtained with CP-immobilized P. ostreatus, which was able to deplete benzo[a]anthracene, chrysene, benzo[b]fluoranthene (BbF), benzo[k]fluoranthene (BkF) and benzo[a]pyrene (BaP) by 69.1%, 29.7%, 39.7%, 32.8% and 85.2%, respectively. Only few high-molecular mass PAHs such as BbF, BkF and BaP were degraded beyond their respective bioavailable fractions and this effect was confined to a limited number of inoculants. In CTS, only phenanthrene degradation exceeded its respective bioavailability from 1.42 to 1.86-fold. Regardless of both inoculum carrier and fungal species, degradation was positively and significantly (P<0.001) correlated with bioavailability in fungal microcosms on HCS and CTS and such correlation was very similar in the two matrices (R(adj)(2) equal to 0.60 and 0.59, respectively). The ability of white-rot fungi to degrade certain PAHs beyond their bioavailability was experimentally proven by this study. Although CTS and HCS considerably differed in their physico-chemical properties, PAH contents and contaminant aging, the relationship between degradation and bioavailability was not significantly affected by the type of matrix.

  1. Caddisflies as biomonitors identifying thresholds of toxic metal bioavailability that affect the stream benthos.

    PubMed

    Rainbow, Philip S; Hildrew, Alan G; Smith, Brian D; Geatches, Tim; Luoma, Samuel N

    2012-07-01

    It has been proposed that bioaccumulated concentrations of toxic metals in tolerant biomonitors be used as indicators of metal bioavailability that could be calibrated against the ecological response to metals of sensitive biotic assemblages. Our hypothesis was that metal concentrations in caddisfly larvae Hydropsyche siltalai and Plectrocnemia conspersa, as tolerant biomonitors, indicate metal bioavailability in contaminated streams, and can be calibrated against metal-specific ecological responses of mayflies. Bioaccumulated concentrations of Cu, As, Zn and Pb in H. siltalai from SW English streams were related to the mayfly assemblage. Mayflies were always sparse where bioavailabilities were high and were abundant and diverse where bioavailabilities of all metals were low, a pattern particularly evident when the combined abundance of heptageniid and ephemerellid mayflies was the response variable. The results offer promise that bioaccumulated concentrations of metals in tolerant biomonitors can be used to diagnose ecological impacts on stream benthos from metal stressors.

  2. Dietary Selenium (Se) and Copper (Cu) Interact to Affect Homocysteine Metabolism in Rats

    USDA-ARS?s Scientific Manuscript database

    Our previous studies have shown that selenium (Se) is protective against dimethylhydrazine (DMH)-induced preneoplastic colon cancer lesions, and protection against DNA damage has been hypothesized to be one mechanism for the anticancer effect of Se. The present study was designed to determine whethe...

  3. Factors affecting intrasubject variability of PK exposure: absolute oral bioavailability and acidic nature of drugs.

    PubMed

    Sato, Masahiko; Narukawa, Mamoru

    2015-11-01

    The aim of the present study is to investigate factors affecting intrasubject variability of pharmacokinetic (PK) exposure, which affect the results of bioequivalence (BE) studies. We focused on two factors: absolute oral bioavailability (BA) and acidic nature of drugs. Intrasubject coefficient of variation (CV) for Cmax and AUC was estimated based on the 90% confidence intervals (CIs) and the number of subjects from fasting BE study results for our investigation. Relationships between the intrasubject CV and the absolute oral BA as well as the acidic nature of the drugs were investigated. First, the relationship between absolute oral BA and intrasubject variability of PK exposure (Cmax and AUC) showed negative log-linear relationship in the BE studies following oral administration of 65 immediate-release drugs under fasted condition. Drugs with poor absolute oral BA of less than 5% showed high intrasubject CV in the range of 30-65%. In contrast, drugs with high absolute oral BA of more than 80% showed low intrasubject CV of less than 20%. Second, acidic drugs with pKa<6 had higher intrasubject CV of Cmax than AUC compared to other types of drugs. The intrasubject CV ratios of Cmax to AUC for acidic drugs with pKa<6 were significantly higher than those for other types of drugs. Results show that absolute oral BA is one of the major factors that predict the extent of intrasubject variability of PK exposure. Acidic nature of drugs is thought to be an additional factor increasing intrasubject variability of Cmax as compared to AUC.

  4. Investigation of the mechanisms affecting Cu and Fe bioavailability from legumes: role of seed protein and antinutritional (nonprotein) factors.

    PubMed

    Carbonaro, M; Grant, G; Mattera, M; Aguzzi, A; Pusztai, A

    2001-01-01

    Chemical composition and content in polyphenols, phytic acid, and dietary fiber of whole cooked common bean (Phaseolus vulgaris L.) and faba bean (Vicia faba L.) and of soluble and insoluble fractions separated from them were determined. Simultaneous determination of Cu, Fe, and protein bioavailability in the small intestine of rat was carried out in single-dose, short-term (1 h) experiments. After cooking, about 80% of seed components (on a weight basis) of either legume was recovered in the precipitate (insoluble fraction) after extraction with water. Protein, lipid, starch, dietary fiber, and polyphenols underwent the most severe insolubilization, together with more than 70% of total Cu and Fe. Cu, Fe, and protein bioavailability showed a similar trend (i.e., the lower the protein, the lower the Cu and Fe availability). Availability of proteins, Cu, and Fe in the insoluble fractions were the lowest, but Cu bioavailability was higher than that of Fe in all fractions. The results provide evidence that the heat-induced insolubilization process adversely affects not only protein but also Cu and Fe bioavailability from legumes and that polyphenols are likely to be a major inhibitor on absorption.

  5. 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.

  6. 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.

  7. Investigation of stillbirths, perinatal mortality and weakness in beef calves with low-selenium whole blood concentrations.

    PubMed

    Davis, Anthony J; Myburgh, Jan G

    2016-07-15

    In this on-farm investigation, we report on stillbirths, weakness and perinatal mortality seen in calves on a commercial beef farm in the Roossenekal area, Mpumalanga province, South Africa. Post-mortem examination of these calves and histopathological examination of organ and tissue samples did not indicate an infectious aetiology. Affected calves had marginal to deficient whole blood selenium concentrations. Whole blood samples collected from adult cattle on this farm and five neighbouring farms were deficient in selenium. The potential contributions of other minerals to the symptoms seen are a subject of ongoing investigation, but selenium deficiency was marked in this herd and required urgent correction. Methods to correct the deficiency included the use of injectable products, and an oral selenium supplement chelated to methionine. Selenium availability to plants is primarily determined by the selenium content of the parent bedrock, the presence of other minerals and the pH of the soil. The apparent sudden onset of this problem implicates a soil factor as being responsible for reducing selenium's bioavailability in this area. Selenium deficiency can have a significant impact on human health. HIV and/or AIDS, various forms of cancer and several specific clinical syndromes are associated with selenium deficiency in humans, and the impact on human health in this area also requires further investigation.

  8. Streamflow and water-quality conditions including geologic sources and processes affecting selenium loading in the Toll Gate Creek watershed, Aurora, Arapahoe County, Colorado, 2007

    USGS Publications Warehouse

    Paschke, Suzanne S.; Runkel, Robert L.; Walton-Day, Katherine; Kimball, Briant A.; Schaffrath, Keelin R.

    2013-01-01

    Toll Gate Creek is a perennial stream draining a suburban area in Aurora, Colorado, where selenium concentrations have consistently exceeded the State of Colorado aquatic-life standard for selenium of 4.6 micrograms per liter since the early 2000s. In cooperation with the City of Aurora, Colorado, Utilities Department, a synoptic water-quality study was performed along an 18-kilometer reach of Toll Gate Creek extending from downstream from Quincy Reservoir to the confluence with Sand Creek to develop a detailed understanding of streamflow and concentrations and loads of selenium in Toll Gate Creek. Streamflow and surface-water quality were characterized for summer low-flow conditions (July–August 2007) using four spatially overlapping synoptic-sampling subreaches. Mass-balance methods were applied to the synoptic-sampling and tracer-injection results to estimate streamflow and develop spatial profiles of concentration and load for selenium and other chemical constituents in Toll Gate Creek surface water. Concurrent groundwater sampling determined concentrations of selenium and other chemical constituents in groundwater in areas surrounding the Toll Gate Creek study reaches. Multivariate principal-component analysis was used to group samples and to suggest common sources for dissolved selenium and major ions. Hydrogen and oxygen stable-isotope ratios, groundwater-age interpretations, and chemical analysis of water-soluble paste extractions from core samples are presented, and interpretation of the hydrologic and geochemical data support conclusions regarding geologic sources of selenium and the processes affecting selenium loading in the Toll Gate Creek watershed.

  9. Biofortification and Bioavailability of Rice Grain Zinc as Affected by Different Forms of Foliar Zinc Fertilization

    PubMed Central

    Yang, Xiaoe

    2012-01-01

    Background Zinc (Zn) biofortification through foliar Zn application is an attractive strategy to reduce human Zn deficiency. However, little is known about the biofortification efficiency and bioavailability of rice grain from different forms of foliar Zn fertilizers. Methodology/Principal Findings Four different Zn forms were applied as a foliar treatment among three rice cultivars under field trial. Zinc bioavailability was assessed by in vitro digestion/Caco-2 cell model. Foliar Zn fertilization was an effective agronomic practice to promote grain Zn concentration and Zn bioavailability among three rice cultivars, especially, in case of Zn-amino acid and ZnSO4. On average, Zn-amino acid and ZnSO4 increased Zn concentration in polished rice up to 24.04% and 22.47%, respectively. On average, Zn-amino acid and ZnSO4 increased Zn bioavailability in polished rice up to 68.37% and 64.43%, respectively. The effectiveness of foliar applied Zn-amino acid and ZnSO4 were higher than Zn-EDTA and Zn-Citrate on improvement of Zn concentration, and reduction of phytic acid, as a results higher accumulation of bioavailable Zn in polished rice. Moreover, foliar Zn application could maintain grain yield, the protein and minerals (Fe and Ca) quality of the polished rice. Conclusions Foliar application of Zn in rice offers a practical and useful approach to improve bioavailable Zn in polished rice. According to current study, Zn-amino acid and ZnSO4 are recommended as excellent foliar Zn forms to ongoing agronomic biofortification. PMID:23029003

  10. 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 ...

  11. Influence of domestic processing on the bioaccessibility of selenium from selected food grains and composite meals.

    PubMed

    Khanam, Anjum; Platel, Kalpana

    2016-03-01

    Selenium, an ultra trace element with several health beneficial attributes, should be mainly derived from dietary sources. Since food processing is likely to alter the bioavailability of micronutrients, the influence of such processing such as germination and fermentation on selenium content and bioaccessibility, information on which is lacking, was examined in this study. Bioaccessibility of selenium from four cereal-based composite meals was also studied. Chickpea, green gram and finger millet were employed to study the effect of germination, and for effect of fermentation, batters used in preparation dosa, idli and dhokla were used. Soaking the grains in water as a part of germination and fermentation brought about a decrease in selenium content, while its bioaccessibility was not affected. The information on the loss of selenium during soaking and heat processing of the germinated grains is novel. Fermentation resulted in a further decrease in selenium content, the percent decrease ranging from 26 to 47 in the batters. Similar decreases were seen in the bioaccessible selenium content as a result of soaking and fermentation. Cooking of the fermented batters, however, significantly enhanced the bioaccessibility of selenium from dosa and dhokla by 44 and 71 %, respectively. Selenium content of the four meals ranged from 150 to 228.8 ng/g. Bioaccessible selenium was highest in the finger millet-based meal (32.8 ng/g), followed by sorghum, wheat and rice-based meals. The present investigation thus provides vital and novel information on selenium content and bioaccessibility from foods subjected to processing as is commonly practiced in Indian households.

  12. Technical issues affecting the implementation of US Environmental Protection Agency's proposed fish tissue-based aquatic criterion for selenium.

    PubMed

    Lemly, A Dennis; Skorupa, Joseph P

    2007-10-01

    The US Environmental Protection Agency is developing a national water quality criterion for selenium that is based on concentrations of the element in fish tissue. Although this approach offers advantages over the current water-based regulations, it also presents new challenges with respect to implementation. A comprehensive protocol that answers the "what, where, and when" is essential with the new tissue-based approach in order to ensure proper acquisition of data that apply to the criterion. Dischargers will need to understand selenium transport, cycling, and bioaccumulation in order to effectively monitor for the criterion and, if necessary, develop site-specific standards. This paper discusses 11 key issues that affect the implementation of a tissue-based criterion, ranging from the selection of fish species to the importance of hydrological units in the sampling design. It also outlines a strategy that incorporates both water column and tissue-based approaches. A national generic safety-net water criterion could be combined with a fish tissue-based criterion for site-specific implementation. For the majority of waters nationwide, National Pollution Discharge Elimination System permitting and other activities associated with the Clean Water Act could continue without the increased expense of sampling and interpreting biological materials. Dischargers would do biotic sampling intermittently (not a routine monitoring burden) on fish tissue relative to the fish tissue criterion. Only when the fish tissue criterion is exceeded would a full site-specific analysis including development of intermedia translation factors be necessary.

  13. Selenium and human health.

    PubMed

    Rayman, Margaret P

    2012-03-31

    Selenium is incorporated into selenoproteins that have a wide range of pleiotropic effects, ranging from antioxidant and anti-inflammatory effects to the production of active thyroid hormone. In the past 10 years, the discovery of disease-associated polymorphisms in selenoprotein genes has drawn attention to the relevance of selenoproteins to health. Low selenium status has been associated with increased risk of mortality, poor immune function, and cognitive decline. Higher selenium status or selenium supplementation has antiviral effects, is essential for successful male and female reproduction, and reduces the risk of autoimmune thyroid disease. Prospective studies have generally shown some benefit of higher selenium status on the risk of prostate, lung, colorectal, and bladder cancers, but findings from trials have been mixed, which probably emphasises the fact that supplementation will confer benefit only if intake of a nutrient is inadequate. Supplementation of people who already have adequate intake with additional selenium might increase their risk of type-2 diabetes. 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 selenium intake may benefit people with low status, those with adequate-to-high status might be affected adversely and should not take selenium supplements.

  14. Bioavailability of organic phosphorus to Pseudokirchneriella subcapitata as affected by phosphorus starvation: an isotope dilution study.

    PubMed

    Van Moorleghem, Christoff; De Schutter, Nynke; Smolders, Erik; Merckx, Roel

    2013-06-01

    Phosphorus (P) starved algae have a capacity to rapidly take up P when resupplied to P. This study was set-up to measure to what extent P starvation enhances the potential of algae to utilize organic P forms. The initial (<0.5 h) PO4 uptake rates of cells of Pseudokirchneriella subcapitata increased up to 18-fold with increasing starvation. Algae from different levels of P starvation were subsequently exposed to different model organic P forms and carrier-free (33)PO4. Uptake (1h) of P from organic P-increased up to 5-fold with increasing P starvation. The bioavailability of organic P, relative to PO4, was calculated from uptake of (31)P and (33)P isotopes assuming no isotopic exchange with organic P-forms. This relative bioavailability ranged from 0 to 57% and remained generally unaffected by the extent of P-starvation. This result was found for cells that were either or not treated by a wash method to remove extracellular phosphatases. Short-term P uptake rate sharply increases with decreasing internal P content of the algal cells but the bioavailability of organic P, relative to PO4, is not enhanced. Such finding suggests that P-starvation enhances PO4 uptake capacity and organic P hydrolysis capacity to about the same extent.

  15. Heat-treated hull flour does not affect iron bioavailability in rats.

    PubMed

    Martino, Hércia Stampini Duarte; Carvalho, Ariela Werneck de; Silva, Cassiano Oliveira da; Dantas, Maria Inês de Souza; Natal, Dorina Isabel Gomes; Ribeiro, Sônia Machado Rocha; Costa, Neuza Maria Brunoro

    2011-06-01

    In this study the chemical composition and iron bioavailability of hull and hull-less soybean flour from the new cultivar UFVTN 105AP was evaluated. The hemoglobin depletion-repletion method was used in Wistar rats. Soybean hull flour presented 37% more total dietary fiber and higher content of iron than hull-less soybean flour. The phytate:iron molar ratio, however, was 2-fold lower in the soybean hull flour in compared to the hull-less soybean flour. Animals fed soybean hull flour presented hemoglobin gains similar to those of the control diet group (p > 0.05). The Relative Biological Values of hull and hull-less soybean flour were 68.5% and 67.1%, respectively, compared to the control group. Heat-treated soybean hull flour (150 degrees C/30 minutes) showed high content of iron and low phytate, which favors the iron bioavailability. Thus, the soybean hull flour is a better source of dietary fiber and iron than hull-less soybean flour at comparable bioavailabilities.

  16. Bioavailability assessment of hexachlorobenzene in soil as affected by wheat straw biochar.

    PubMed

    Song, Yang; Wang, Fang; Bian, Yongrong; Kengara, Fredrick Orori; Jia, Mingyun; Xie, Zubin; Jiang, Xin

    2012-05-30

    Biochar incorporation with soil could increase sorption of organic contaminants, thereby reducing their bioavailability. In this study, the effects of wheat straw biochar on the sorption, dissipation and bioavailability of hexachlorobenzene (HCB), a typical persistent organic pollutant (POP), were investigated in laboratory experiments. We observed that HCB sorption by biochar was 42 times higher than that by soil and the sorption isotherm was linear for the concentration range studied. Biochar amendments reduced HCB dissipation, volatilization and earthworm (Eisenia foetida) uptake of HCB from soil. Hydroxypropyl-β-cyclodextrin extraction correlated better with the earthworm bioassay than butanol extraction of HCB in biochar-amended soil. The results of both chemical extraction and earthworm bioassay indicate that biochar amendment of soil resulted in a rapid reduction in the bioavailability of HCB, even for the 0.1% biochar application rate. This suggested that wheat straw biochar could potentially be used in immobilizing POPs in contaminated sites. Copyright © 2012. Published by Elsevier B.V.

  17. Dietary Selenium Levels Affect Selenoprotein Expression and Support the Interferon-γ and IL-6 Immune Response Pathways in Mice

    PubMed Central

    Tsuji, Petra A.; Carlson, Bradley A.; Anderson, Christine B.; Seifried, Harold E.; Hatfield, Dolph L.; Howard, Michael T.

    2015-01-01

    Selenium is an essential element that is required to support a number of cellular functions and biochemical pathways. The objective of this study was to examine the effects of reduced dietary selenium levels on gene expression to assess changes in expression of non-selenoprotein genes that may contribute to the physiological consequences of selenium deficiency. Mice were fed diets that were either deficient in selenium or supplemented with selenium in the form of sodium selenite for six weeks. Differences in liver mRNA expression and translation were measured using a combination of ribosome profiling, RNA-Seq, microarrays, and qPCR. Expression levels and translation of mRNAs encoding stress-related selenoproteins were shown to be up-regulated by increased selenium status, as were genes involved in inflammation and response to interferon-γ. Changes in serum cytokine levels were measured which confirmed that interferon-γ, as well as IL-6, were increased in selenium adequate mice. Finally, microarray and qPCR analysis of lung tissue demonstrated that the selenium effects on immune function are not limited to liver. These data are consistent with previous reports indicating that adequate selenium levels can support beneficial immune responses, and further identify the IL-6 and interferon-γ pathways as being responsive to dietary selenium intake. PMID:26258789

  18. Dietary Selenium Levels Affect Selenoprotein Expression and Support the Interferon-γ and IL-6 Immune Response Pathways in Mice.

    PubMed

    Tsuji, Petra A; Carlson, Bradley A; Anderson, Christine B; Seifried, Harold E; Hatfield, Dolph L; Howard, Michael T

    2015-08-06

    Selenium is an essential element that is required to support a number of cellular functions and biochemical pathways. The objective of this study was to examine the effects of reduced dietary selenium levels on gene expression to assess changes in expression of non-selenoprotein genes that may contribute to the physiological consequences of selenium deficiency. Mice were fed diets that were either deficient in selenium or supplemented with selenium in the form of sodium selenite for six weeks. Differences in liver mRNA expression and translation were measured using a combination of ribosome profiling, RNA-Seq, microarrays, and qPCR. Expression levels and translation of mRNAs encoding stress-related selenoproteins were shown to be up-regulated by increased selenium status, as were genes involved in inflammation and response to interferon-γ. Changes in serum cytokine levels were measured which confirmed that interferon-γ, as well as IL-6, were increased in selenium adequate mice. Finally, microarray and qPCR analysis of lung tissue demonstrated that the selenium effects on immune function are not limited to liver. These data are consistent with previous reports indicating that adequate selenium levels can support beneficial immune responses, and further identify the IL-6 and interferon-γ pathways as being responsive to dietary selenium intake.

  19. Form of supplemental selenium fed to cycling cows affects systemic concentrations of progesterone but not those of estradiol.

    PubMed

    Cerny, Katheryn L; Anderson, Les; Burris, Walter R; Rhoads, Michelle; Matthews, James C; Bridges, Phillip J

    2016-03-15

    In areas where soils are deficient in selenium (Se), dietary supplementation of this trace mineral directly to cattle is recommended. Selenium status affects fertility, and the form of Se supplemented to cows affects tissue-specific gene expression profiles. The objective of this study was to determine whether the form of Se consumed by cows would affect follicular growth and the production of steroids. Thirty-three Angus-cross cows that had ad libitum access of a mineral mix containing 35 ppm of Se in free-choice vitamin-mineral mixes as either inorganic (ISe), organic (OSe), or a 50/50 mix of ISe and OSe (MIX) for 180 days were used. After 170 days of supplementation, all cows were injected with 25-mg PGF2α to induce regression of the CL and then monitored for behavioral estrus (Day 0). From Day 4 to Day 8 after estrus, follicular growth was determined by transrectal ultrasonography. On Day 6, cows were injected with PGF2α (20 then 15 mg, 8-12 hours apart) to induce regression of the developing CL and differentiation of the dominant follicle of the first follicular wave into a preovulatory follicle. On Day 8, 36 hours after PGF2α (20 mg), the contents of the preovulatory follicle were aspirated by ultrasound-guided follicular puncture. Blood collected on Days 6 and 8 and follicular fluid collected on Day 8 was analyzed for concentrations of progesterone and estradiol. Form of Se supplemented to cows affected (P = 0.04) the systemic concentration of progesterone on Day 6, but not on Day 8. Form of Se did not affect the systemic concentration of estradiol on Day 6 or Day 8. Form of Se tended to affect (P = 0.07) the concentration of progesterone, but not that of estradiol, in the follicular fluid. Form of Se did not affect diameter of the dominant ovarian follicle on Days 4 to 6, but tended to affect (P = 0.08) the diameter of the preovulatory follicle on Day 8. Our results suggest that form of Se fed to cows affects the production of progesterone but not that

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

    PubMed

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

    2016-11-15

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

  1. Effects of selenite and selenate application on distribution and transformation of selenium fractions in soil and its bioavailability for wheat (Triticum aestivum L.).

    PubMed

    Ali, Fayaz; Peng, Qin; Wang, Dan; Cui, Zewei; Huang, Jie; Fu, Dongdong; Liang, Dongli

    2017-03-01

    This study investigated the effect of selenate and selenite application on the distribution, transformation of selenium (Se) fractions in soil, as well as the accumulation and availability of Se in each part of wheat plants. A pot experiment was conducted using different concentrations of exogenous selenite or selenate (0.5, 1, 2.5, 5, and 10 mg Se kg(-1) soil). Sequential extraction was used to determine the Se fractions in soil, and different models were used to study the behavior of Se in soil and its availability to wheat. Results showed that the distribution and availability of Se in soil and its accumulation in wheat affected both by Se concentrations and forms of exogenous Se. In selenite-treated soil, the proportion of exchangeable and carbonate-bound Se (EXC-Se) (21-42%) fraction increased compared to that in control (12%), while organic matter-bound Se (OM-Se) (23-33%) and Fe-Mn oxide-bound Se (FMO-Se) (11-15%) fractions decreased compare with those in control (37 and 32%, respectively). In selenate-treated soil, soluble-Se (SOL-Se) fraction (30-54%) increased and the OM-Se (9.8-20%) and FMO-Se (4.7-14.2%) fractions decreased compared with those in control. Residual Se (RES-Se) fraction was increased for selenite (7.4-13.4%) and selenate (12-20%) treatments compared with that in control (6.5%). In comparison with control, the available Se (SOL-Se + EXC-Se) fraction increased for both selenite (32-47%) or selenate (54-72%) treatments. Moreover, at the same rate of Se application, Se availability was higher in wheat grown in selenate-treated soils than that in selenite-treated soils. The redistribution index (U ts) of Se increased from 1 (in control) to 1.2-1.9 and 1.5-2 for selenite and selenate treatments, respectively; additionally, the mobility factor (MF) in selenate-treated soil was 40-90% higher than that in selenite-treated soil. Furthermore, relative bonding intensity (I R ) for both selenite (0.38-0.45) and selenate treatment (0

  2. The poor bioavailability of elemental iron in corn masa flour is not affected by disodium EDTA.

    PubMed

    Walter, Tomas; Pizarro, Fernando; Boy, Erick; Abrams, Steven A

    2004-02-01

    The most sustainable way to eradicate iron deficiency is through food fortification. Elemental iron powders are commonly utilized as fortificants due to their low cost and few sensory problems. However, their bioavailability is unknown. Our goals were to measure the bioavailability of elemental iron in Mexican style corn masa flour tortillas and to evaluate the effects of Na(2)EDTA. We used a stable isotope of H(2)-reduced iron powder, with and without Na(2)EDTA in tortillas prepared with corn masa flour. Two groups of 5- to 7-y-old children (n = 12/group) were fed tortillas to which was added 3 mg/100 g of H(2)-reduced (58)Fe with a mean particle size of 15 micro m. In one group, Na(2)EDTA was incorporated at a ratio of 1:2 mol/mol. The next day, (57)Fe ascorbate was given as a reference dose. After 14 d, blood samples were analyzed for isotopic enrichment. When normalized to 40% absorption of the reference dose, the geometric mean (+/-range 1 SD) bioavailability of reduced iron in tortilla was 3.8% (2.7-5.3). The addition of Na(2)EDTA, tended to increase it (P = 0.18) to 5.1% (2.8-9.2). This observed low absorption was compounded by the use of iron isotopes with smaller particle size (mean diameter 15 micro m) than typical of commercial elemental iron powder (<45 micro m). We conclude that H(2)-reduced iron powder is an ineffective fortificant in corn tortillas.

  3. Factors affecting mercury and selenium levels in New Jersey flatfish: low risk to human consumers.

    PubMed

    Burger, Joanna; Jeitner, Christian; Donio, Mark; Shukla, Sheila; Gochfeld, Michael

    2009-01-01

    Some fish contain high levels of mercury (Hg), which could pose a risk to fish eaters themselves or their children. In making decisions about fish consumption, people must decide whether to eat fish, how much to eat, what species to eat, and what size fish to eat, as well as suitable (or unsuitable) locations, among other factors. Yet to make sound decisions, people need to know the levels of Hg in fish as a function of species, size, and location of capture. Levels of Hg and selenium (Se) were examined in three species of flatfish (fluke or summer flounder [Paralichthys dentatus], winter flounder [Pseudopleuronectes americanus], and windowpane [Scophthalmus aquosus]) from New Jersey as a function of species, fish size, season, and location. Flatfish were postulated to have low levels of Hg because they are low on the food chain and are bottom feeders, and data were generated to provide individuals with information on a species that might be safe to eat regularly. Although there were interspecific differences in Hg levels in the 3 species, total Hg levels averaged 0.18, 0.14, and 0.06 ppm (microg/g, wet weigh) in windowpane, fluke, and winter flounder, and selenium levels averaged 0.36, 0.35, and 0.25 ppm, respectively. For windowpane, 15% had Hg levels above 0.3 ppm, but no individual fish had Hg levels over 0.5 ppm. There were no significant seasonal differences in Hg levels, although Se was significantly higher in fluke in summer compared to spring. There were few geographical differences among New Jersey locations. Correlations between Hg and Se levels were low. Data, based on 464 fish samples, indicate that Hg levels are below various advisory levels and pose little risk to typical New Jersey fish consumers. A 70-kg person eating 1 meal (8 oz or 227 g) per week would not exceed the U.S. Environmental Protection Agency reference dose of 0.1 microg/kg body weight/d of methylmercury (MeHg). However, high-end fish eaters consuming several such meals per week may

  4. Factors Affecting Mercury and Selenium Levels-in New Jersey Flatfish: Low Risk to Human Consumers

    PubMed Central

    Burger, Joanna; Jeitner, Christian; Donio, Mark; Shukla, Sheila; Gochfeld, Michael

    2014-01-01

    Some fish contain high levels of mercury (Hg), which could pose a risk to fish eaters themselves or their children. In making decisions about fish consumption, people must decide whether to eat fish, how much to eat, what species to eat, and what size fish to eat, as well as suitable (or unsuitable) locations, among other factors. Yet to make sound decisions, people need to know the levels of Hg in fish as a function of species, size, and location of capture. Levels of Hg and selenium (Se) were examined in three species of flatfish (fluke or summer flounder [Paralichthys dentatus], winter flounder [Pseudopleuronectes americanus], and windowpane [Scophthalmus aquosus]) from New Jersey as a function of species, fish size, season, and location. Flatfish were postulated to have low levels of Hg because they are low on the food chain and are bottom feeders, and data were generated to provide individuals with information on a species that might be safe to eat regularly. Although there were interspecific differences in Hg levels in the 3 species, total Hg levels averaged 0.18, 0.14, and 0.06 ppm (μg/g, wet weigh) in windowpane, fluke, and winter flounder, and selenium levels averaged 0.36, 0.35, and 0.25 ppm, respectively. For windowpane, 15% had Hg levels above 0.3 ppm, but no individual fish had Hg levels over 0.5 ppm. There were no significant seasonal differences in Hg levels, although Se was significantly higher in fluke in summer compared to spring. There were few geographical differences among New Jersey locations. Correlations between Hg and Se levels were low. Data, based on 464 fish samples, indicate that Hg levels are below various advisory levels and pose little risk to typical New Jersey fish consumers. A 70-kg person eating 1 meal (8 oz or 227 g) per week would not exceed the U.S. Environmental Protection Agency reference dose of 0.1 μg/kg body weight/d of methylmercury (MeHg). However, high-end fish eaters consuming several such meals per week may exceed

  5. A procedure for developing ecosystem loading limits (TMDLs) for selenium in Wastersheds affected by gold mining in Northern Argentina

    Treesearch

    Dennis A. Lemly

    2001-01-01

    The Argentina Federal Secretary of Natural Resources oversees a wide array of mining operations conducted on public lands. Recently, selenium has emerged as a contaminant issue associated with several gold mines in the northern mountain ranges. The Secretary's Office contacted me and requested assistance interpreting selenium concentrations and possible impacts on...

  6. Analysis of bioavailable Ge in agricultural and mining-affected-soils in Freiberg area (Saxony, Germany)

    NASA Astrophysics Data System (ADS)

    Wiche, Oliver; Székely, Balázs; Kummer, Nicolai-Alexeji; Heinemann, Ute; Heilmeier, Hermann

    2014-05-01

    Germanium (Ge) concentrations in different soil fraction were investigated using a sequential selective dissolution analysis and a rhizosphere-based single-step extraction method for the identification of Ge-bearing soil fractions and prediction of bioavailability of Ge in soil to plants. About 50 soil samples were collected from various soil depths (horizons A and B) and study sites with different types of land use (dry and moist grassland, arable land, mine dumps) in Freiberg area (Saxony, Germany). Ge has been extracted in six soil fractions: mobile fraction, organic matter and sulfides, Mn- and Fe-oxides (amorphous and crystalline), and kaolinite and phytoliths, and residual fraction. The rhizosphere-based method included a 7-day-long extraction sequence with various organic acids like citric acid, malic acid and acetic acid. For the residue the aforementioned sequential extraction has been applied. The Ge-content of the samples have been measured with ICP-MS using rhodium internal standard and two different soil standards. Total Ge concentrations were found to be in the range of 1.6 to 5.5 ppm with highest concentrations on the tailing site in the mining area of Altenberg. The mean Ge concentration in agriculturally used soils was 2.6 ± 0.67 ppm, whereas the maximum values reach 2.9 ± 0.64 ppm and 3.2 ± 0.67 ppm in Himmelsfürst and in a grassland by the Mulde river, respectively. With respect to the fractions, the vast majority of Ge is contained in the last three fractions, indicating that the bioavailable Ge is typically low in the samples. On the other hand at the soil horizons A at the aforementioned two sites characterised by high total Ge, together with that of Reiche Zeche mine dump have also the highest concentrations of Ge in the first three fractions, reaching levels of 1.74 and 0.98 ppm which account for approximately 40% of the total Ge content. Ge concentrations of soil samples extracted with 0.01 or 0.1 M citric acid and malic acid were

  7. Iron status and food matrix strongly affect the relative bioavailability of ferric pyrophosphate in humans.

    PubMed

    Moretti, Diego; Zimmermann, Michael B; Wegmüller, Rita; Walczyk, Thomas; Zeder, Christophe; Hurrell, Richard F

    2006-03-01

    Although ferric pyrophosphate is a promising compound for iron fortification of foods, few data are available on the effect of food matrices, processing, and ascorbic acid on its bioavailability. We compared the relative bioavailability (RBV) of ferrous sulfate in an experimental form of micronized dispersible ferric pyrophosphate (MDFP) in a wheat-milk infant cereal given with and without ascorbic acid with the RBV of MDFP from a processed and unprocessed rice meal. A crossover design was used to measure iron absorption in young women (n = 26) from test meals fortified with isotopically labeled [57Fe]-MDFP and [58Fe]-ferrous sulfate, based on erythrocyte incorporation of stable isotope labels 14 d later. Geometric mean iron absorption from the wheat-based meal fortified with MDFP was 2.0% and that from the meal fortified with ferrous sulfate was 3.2% (RBV = 62). The addition of ascorbic acid at a molar ratio of 4:1 to iron increased iron absorption from MDFP to 5.8% and that from ferrous sulfate to 14.8% (RBV = 39). In the rice meals, mean iron absorption from MDFP added to the rice at the time of feeding was 1.7%, and that from ferrous sulfate was 11.6% (RBV = 15). The mean iron absorption from MDFP extruded into artificial rice grains was 3.0% and that from ferrous sulfate in unprocessed rice was 12.6% (RBV = 24). Sixteen of 26 subjects were iron deficient. Iron status was a highly significant predictor of the RBV of MDFP (P < 0.001). RBV of the experimental MDFP varied markedly with food matrix and iron status. Assigning a single RBV value to poorly soluble compounds may be of limited value in evaluating their suitability for food fortification.

  8. Have the bioavailabilities of trace metals to a suite of biomonitors changed over three decades in SW England estuaries historically affected by mining?

    PubMed

    Rainbow, P S; Kriefman, S; Smith, B D; Luoma, S N

    2011-03-15

    Many estuaries of southwest England were heavily contaminated with toxic metals associated with the mining of copper and other metals, particularly between 1850 and 1900. The question remains whether the passage of time has brought remediation to these estuaries. In 2003 and 2006 we revisited sites in 5 metal-contaminated estuaries sampled in the 1970s and 1980s - Restronguet Creek, Gannel, West Looe, East Looe and Tavy. We evaluate changes in metal contamination in sediments and in metal bioavailabilities in sediments and water to local organisms employed as biomonitors. We find that the decline in contamination in these estuaries is complex. Differences in bioavailable contamination in the water column were detectable, as were significant detectable changes in at least some estuaries in bioavailable metal contamination originating from sediments. However, in the 100 years since mining activities declined, bioavailable contamination has not declined to the regional baseline in any estuary affected by the mine wastes. The greatest decline in contamination occurred in the one instance (East Looe) where a previous industrial source of (Ag) contamination was considered. We used the macroalgae Fucus vesiculosus and Ascophyllum nodosum as biomonitors of dissolved metal bioavailabilities and the deposit feeders Nereis diversicolor and Scrobicularia plana as biomonitors of bioavailable metal in sediments. We found no systematic decrease in the atypically high Ag, Cu, Pb and Zn concentrations in the estuarine sediments over a 26 year period. Accumulated metal (Ag, As, Cu, Pb, and Zn) concentrations in the deposit feeders are similarly still atypically high in at least one estuary for each metal, and there is no consistent evidence for general decreases in sediment metal bioavailabilities over time. We conclude that the legacy of mining in sheltered estuaries of southwest England is the ongoing presence of sediments rich in metals bioavailable to deposit feeders, while

  9. Human Lung Cancer Cell Line A-549 ATCC Is Differentially Affected by Supranutritional Organic and Inorganic Selenium

    PubMed Central

    Flores Villavicencio, Lérida Liss; Cruz-Jiménez, Gustavo; Barbosa-Sabanero, Gloria; Kornhauser-Araujo, Carlos; Mendoza-Garrido, M. Eugenia; de la Rosa, Guadalupe; Sabanero-López, Myrna

    2014-01-01

    The effects of organic and inorganic forms of selenium (Se) on human cells have been extensively studied for nutritional concentrations; however, to date, little is known about the potential toxicity at supranutritional levels. In the present study we determined the effects of sodium selenite (SSe) and selenomethionine (SeMet) on cell growth and intracellular structures in lung cancer cells exposed at Se concentrations between 0 and 3 mM. Our results showed that SSe affected cell growth more rapidly than SeMet (24 h and 48 h, resp.). After 24 h of cells exposure to 0.5, 1.5, and 3 mM SSe, cell growth was reduced by 10, 50, and 60%, as compared to controls. After 48 h, nuclear fragmentation was evident in cells exposed to SSe, suggesting an induction to cell death. In contrast, SeMet did not affect cell proliferation, and the cells were phenotypically similar to controls. Microtubules and microfilaments structures were also affected by both Se compounds, again SSe being more toxic than SeMet. To our knowledge, this is the first report on the differential effects of organic and inorganic Se in supranutritional levels in lung cancer cells. PMID:25477771

  10. Soil Redox Chemistry Limitation of Selenium Concentration in Carex Species Sedges

    SciTech Connect

    Bruce J. Mincher; John Mionczynski; Patrick A. Hnilicka

    2007-09-01

    The trace element selenium (Se) is required in the production of enzymes that protect mammalian cells from oxidative damage due to the byproducts of aerobic respiration. Its deficiency in livestock results in the nutritional muscular dystrophy called white muscle disease. This especially affects juveniles in the preweaning period. Symptoms have also been reported in wild herbivores on low-Se forage, and their appearance may be episodic, suggesting temporal variations in Se uptake by plants. Here, we report variations in selenium concentrations in Carex spp. sedges used as forage by bighorn sheep (Ovis canadensis) on summer range in the Wyoming, Wind River Mountains, and correlate those variations with soil conditions that affect the bioavailability of selenium. Variations in available Se are explained based upon the known oxidation/reduction chemistry of the element. It is concluded that water-saturated, alpine soils provide conditions suitable for the reduction of Se to the unavailable, elemental form, limiting its concentration in forage plants.

  11. Kolliphor surfactants affect solubilization and bioavailability of fenofibrate. Studies of in vitro digestion and absorption in rats.

    PubMed

    Berthelsen, Ragna; Holm, René; Jacobsen, Jette; Kristensen, Jakob; Abrahamsson, Bertil; Müllertz, Anette

    2015-04-06

    Selection of excipients for drug formulations requires both intellectual and experimental considerations as many of the used excipients are affected by physiological factors, e.g., they may be digested by pancreatic enzymes in the gastrointestinal tract. In the present paper we have looked systematically into the differences between Kolliphor ELP, EL, and RH40 and how they affect the bioavailability of fenofibrate, through pharmacokinetic studies in rats and in vitro lipolysis studies. The study design was made as simple as possible to avoid confounding factors, for which reason the tested formulations only comprised an aqueous micellar solution of the model drug (fenofibrate) in varying concentrations (2-25% (w/v)) of the three tested surfactants. Increased concentrations of Kolliphor ELP and EL led to increased fenofibrate AUC0-24h values. For the Kolliphor RH40 formulations, an apparent fenofibrate absorption optimum was seen at 15% (w/v) surfactant, displaying both the highest AUC0-24h and Cmax. The reduced absorption of fenofibrate from the formulation containing the highest level of surfactant (25% w/v) was thought to be caused by some degree of trapping within Kolliphor RH40 micelles. In vitro, Kolliphor ELP and EL were found to be more prone to digestion than Kolliphor RH40, though not affecting the in vivo results. The highest fenofibrate bioavailability was attained from formulations with high Kolliphor ELP/EL levels (25% (w/v)), indicating that these surfactants are the better choice for solubilizing fenofibrate in order to increase the absorption upon oral administration. Due to drug dependent effects of the different types of Kolliphor, more studies are recommended in order to understand which type of Kolliphor is best suited for a given drug.

  12. Factors affecting the soil arsenic bioavailability, accumulation in rice and risk to human health: a review.

    PubMed

    Azam, Shah Md Golam Gousul; Sarker, Tushar C; Naz, Sabrina

    2016-10-01

    Arsenic (As), a class one carcinogen, reflects a disastrous environmental threat due to its presence in each and every compartment of the environment. The high toxicity of As is notably present in its inorganic forms. Irrigation with As contaminated groundwater in rice fields increases As concentration in topsoil and its bioavailability for rice crops. However, most of the As in paddy field topsoils is present as As(III) form, which is predominant in rice grain. According to the OECD-FAO, rice is the second most extensively cultivated cereal throughout the world. This cereal is a staple food for a large number of populations in most of the developing countries in sub-Saharan Africa, Latin America, South and South-east Asia. Rice consumption is one of the major causes of chronic As diseases including cancer for Asian populations. Thus, this review provides an overview concerning the conditions involved in soil that leads to As entrance into rice crops, phytotoxicity and metabolism of As in rice plants. Moreover, the investigations of the As uptake in raw rice grain are compiled, and the As biotransfer into the human diet is focused. The As uptake by rice crop represents an important pathway of As exposure in countries with high rice and rice-based food consumption because of its high (more than the hygienic level) As levels found in edible plant part for livestock and humans.

  13. Surface applied water treatment residuals affect bioavailable phosphorus losses in Florida sands.

    PubMed

    Oladeji, Olawale O; O'Connor, George A; Brinton, Scott R

    2008-09-01

    Water treatment residuals (WTR) can reduce runoff P loss and surface co-application of P-sources and WTR is a practical way of land applying the residuals. In a rainfall simulation study, we evaluated the effects of surface co-applied P-sources and an Al-WTR on runoff and leacheate bioavailable P (BAP) losses from a Florida sand. Four P-sources, namely poultry manure, Boca Raton biosolids (high water-soluble P), Pompano biosolids (moderate water-soluble P), and triple super phosphate (TSP) were surface applied at 56 and 224 kg P ha(-1) (by weight) to represent low and high soil P loads typical of P- and N-based amendments rates. The treatments further received surface applied WTR at 0 or 10 g WTR kg(-1) soil. BAP loss masses were greater in leachate (16.4-536 mg) than in runoff (0.91-46 mg), but were reduced in runoff and leachate by surface applied WTR. Masses of total BAP lost in the presence of surface applied WTR were less than approximately 75% of BAP losses in the absence of WTR. Total BAP losses from each of the organic sources applied at N-based rates were not greater than P loss from TSP applied at a P-based rate. The BAP loss at the N-based rate of moderate water-soluble P-source (Pompano biosolids) was not greater than BAP losses at the P-based rates of other organic sources tested. The hazards of excess P from applying organic P-sources at N-based rates are not greater than observed at P-based rates of mineral fertilizer. Results suggest that management of the environmental P hazards associated with N-based rates of organic materials in Florida sands is possible by either applying P-sources with WTR or using a moderate water-soluble P-source.

  14. Soil organic matter and salinity affect copper bioavailability in root zone and uptake by Vicia faba L. plants.

    PubMed

    Matijevic, Lana; Romic, Davor; Romic, Marija

    2014-10-01

    Processes that control the mobility, transformation and toxicity of metals in soil are of special importance in the root-developing zone. For this reason, there is a considerable interest in understanding trace elements (TEs) behavior in soil, emphasising the processes by which plants take them up. Increased root-zone salinity can affect plant TEs uptake and accumulation in plant tissue. Furthermore, copper (Cu) complexation by soil organic matter (SOM) is an effective mechanism of Cu retention in soils, controlling thus its bioavailability. Therefore, a greenhouse pot experiment was conducted to study the effects of soil Cu contamination in a saline environment on faba bean (Vicia faba L.) element uptake. Treatment with NaCl salinity was applied (control, 50 mM NaCl and 100 mM NaCl) on faba bean plants grown in a control and in a soil spiked with Cu (250 and 500 mg kg(-1)). Low and high SOM content trial variants were studied. Cu accumulation occurred in faba bean leaf, pod and seed. Cu contamination affected plant element concentrations in leaves (Na, Ca, Mg, Mn), pod (Zn, Mn) and seed (Mn, Mo, Zn). Root-zone salinity also affected faba bean element concentrations. Furthermore, Cu contamination-salinity and salinity-SOM interactions were significant for pod Cu concentration, suggesting that Cu phytoavailability could be affected by these interactions. Future research will be focused on the mechanisms of Cu translocation in plant and adaptation aspects of abiotic stress.

  15. Effects of selenium biofortification on crop nutritional quality.

    PubMed

    Malagoli, Mario; Schiavon, Michela; dall'Acqua, Stefano; Pilon-Smits, Elizabeth A H

    2015-01-01

    Selenium (Se) at very low doses has crucial functions in humans and animals. Since plants represent the main dietary source of this element, Se-containing crops may be used as a means to deliver Se to consumers (biofortification). Several strategies have been exploited to increase plant Se content. Selenium assimilation in plants affects both sulfur (S) and nitrogen (N) metabolic pathways, which is why recent research has also focused on the effect of Se fertilization on the production of S- and N- secondary metabolites with putative health benefits. In this review we discuss the function of Se in plant and human nutrition and the progress in the genetic engineering of Se metabolism to increase the levels and bioavailability of this element in food crops. Particular attention is paid to Se biofortification and the synthesis of compounds with beneficial effects on health.

  16. Effects of selenium biofortification on crop nutritional quality

    PubMed Central

    Malagoli, Mario; Schiavon, Michela; dall’Acqua, Stefano; Pilon-Smits, Elizabeth A. H.

    2015-01-01

    Selenium (Se) at very low doses has crucial functions in humans and animals. Since plants represent the main dietary source of this element, Se-containing crops may be used as a means to deliver Se to consumers (biofortification). Several strategies have been exploited to increase plant Se content. Selenium assimilation in plants affects both sulfur (S) and nitrogen (N) metabolic pathways, which is why recent research has also focused on the effect of Se fertilization on the production of S- and N- secondary metabolites with putative health benefits. In this review we discuss the function of Se in plant and human nutrition and the progress in the genetic engineering of Se metabolism to increase the levels and bioavailability of this element in food crops. Particular attention is paid to Se biofortification and the synthesis of compounds with beneficial effects on health. PMID:25954299

  17. Cooking enhances but the degree of ripeness does not affect provitamin A carotenoid bioavailability from bananas in Mongolian gerbils.

    PubMed

    Bresnahan, Kara A; Arscott, Sara A; Khanna, Harjeet; Arinaitwe, Geofrey; Dale, James; Tushemereirwe, Wilberforce; Mondloch, Stephanie; Tanumihardjo, Jacob P; De Moura, Fabiana F; Tanumihardjo, Sherry A

    2012-12-01

    Banana is a staple crop in many regions where vitamin A deficiency is prevalent, making it a target for provitamin A biofortification. However, matrix effects may limit provitamin A bioavailability from bananas. The retinol bioefficacies of unripe and ripe bananas (study 1A), unripe high-provitamin A bananas (study 1B), and raw and cooked bananas (study 2) were determined in retinol-depleted Mongolian gerbils (n = 97/study) using positive and negative controls. After feeding a retinol-deficient diet for 6 and 4 wk in studies 1 and 2, respectively, customized diets containing 60, 30, or 15% banana were fed for 17 and 13 d, respectively. In study 1A, the hepatic retinol of the 60% ripe Cavendish group (0.52 ± 0.13 μmol retinol/liver) differed from baseline (0.65 ± 0.15 μmol retinol/liver) and was higher than the negative control group (0.39 ± 0.16 μmol retinol/liver; P < 0.0065). In study 1B, no groups differed from baseline (0.65 ± 0.15 μmol retinol/liver; P = 0.20). In study 2, the 60% raw Butobe group (0.68 ± 0.17 μmol retinol/liver) differed from the 60% cooked Butobe group (0.87 ± 0.24 μmol retinol/liver); neither group differed from baseline (0.80 ± 0.27 μmol retinol/liver; P < 0.0001). Total liver retinol was higher in the groups fed cooked bananas than in those fed raw (P = 0.0027). Body weights did not differ even though gerbils ate more green, ripe, and raw bananas than cooked, suggesting a greater indigestible component. In conclusion, thermal processing, but not ripening, improves the retinol bioefficacy of bananas. Food matrix modification affects carotenoid bioavailability from provitamin A biofortification targets.

  18. Reproduction in mallards fed selenium

    USGS Publications Warehouse

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

    1987-01-01

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

  19. 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.

  20. Acute toxicity of the cationic surfactant C12-benzalkonium in different bioassays: how test design affects bioavailability and effect concentrations.

    PubMed

    Chen, Yi; Geurts, Marc; Sjollema, Sascha B; Kramer, Nynke I; Hermens, Joop L M; Droge, Steven T J

    2014-03-01

    Using an ion-exchange-based solid-phase microextraction (SPME) method, the freely dissolved concentrations of C12-benzalkonium were measured in different toxicity assays, including 1) immobilization of Daphnia magna in the presence or absence of dissolved humic acid; 2) mortality of Lumbriculus variegatus in the presence or absence of a suspension of Organisation for Economic Co-Operation and Development (OECD) sediment; 3) photosystem II inhibition of green algae Chlorella vulgaris; and 4) viability of in vitro rainbow trout gill cell line (RTgill-W1) in the presence or absence of serum proteins. Furthermore, the loss from chemical adsorption to the different test vessels used in these tests was also determined. The C12-benzalkonium sorption isotherms to the different sorbent phases were established as well. Our results show that the freely dissolved concentration is a better indicator of the actual exposure concentration than the nominal or total concentration in most test assays. Daphnia was the most sensitive species to C12-benzalkonium. The acute Daphnia and Lumbriculus tests both showed no enhanced toxicity from possible ingestion of sorbed C12-benzalkonium in comparison with water-only exposure, which is in accordance with the equilibrium partitioning theory. Moreover, the present study demonstrates that commonly used sorbent phases can strongly affect bioavailability and observed effect concentrations for C12-benzalkonium. Even stronger effects of decreased actual exposure concentrations resulting from sorption to test vessels, cells, and sorbent phases can be expected for more hydrophobic cationic surfactants.

  1. Technical issues affecting the implementation of US environmental protection agency's proposed fish tissue-based aquatic criterion for selenium

    Treesearch

    A. Dennis Lemly; Joseph P. Skorupa

    2007-01-01

    The US Environmental Protection Agency is developing a national water quality criterion for selenium that is based on concentrations of the element in fish tissue. Although this approach offers advantages over the current water-based regulations, it also presents new challenges with respect to implementation. A comprehensive protocol that answers the ‘‘what, where, and...

  2. Preparation of selenium yeasts I. Preparation of selenium-enriched Saccharomyces cerevisiae.

    PubMed

    Suhajda, A; Hegóczki, J; Janzsó, B; Pais, I; Vereczkey, G

    2000-04-01

    Selenium (Se) is an essential micronutrient for human and animal organisms. Organic selenium complexes and selenium-containing amino acids are considered the most bioavailable. Under appropriate conditions yeasts are capable of accumulating large amounts of trace elements, such as selenium, and incorporating them into organic compounds. It has been found that introduction of water-soluble selenium salt as a component of the culture medium for yeasts produced by conventional batch processing results in a substantial amount of selenium being absorbed by the yeast. Using a culture medium supplemented with 30 microg/mL sodium-selenite added during the exponential growth phase results in selenium-accumulation in the range of 1200-1400 microg/g dried baker's yeast (Saccharomyces cerevisiae) measured by ICP-AES method. In our previous studies it was shown that higher amounts of sodium-selenite in the culture medium have a strong inhibitory effect on the growth of this yeast. As a consequence of variations in cultivation conditions we obtained selenium yeast with different inorganic selenium content. The most important parameters influencing incorporated forms of selenium are pH value and dissolved oxygen level in the culture medium, and depending on these the selenium consumption rate of the yeast. A 0.40-0.50 mg/g h-1 specific selenium consumption rate was found to be appropriate to obtain selenium-enriched bakers' yeast of a high quality. Under suitable conditions the undesirable inorganic selenium content of the yeast could be suppressed to as low as 5-6% at the expense, however, of approximately a 20% decrease in the final biomass.

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

    PubMed

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

    2016-04-01

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

  4. Aging Negatively Affects Estrogens-Mediated Effects on Nitric Oxide Bioavailability by Shifting ERα/ERβ Balance in Female Mice

    PubMed Central

    Novensà, Laura; Novella, Susana; Medina, Pascual; Segarra, Gloria; Castillo, Nadia; Heras, Magda; Hermenegildo, Carlos; Dantas, Ana Paula

    2011-01-01

    Aims Aging is among the major causes for the lack of cardiovascular protection by estrogen (E2) during postmenopause. Our study aims to determine the mechanisms whereby aging changes E2 effects on nitric oxide (NO) production in a mouse model of accelerated senescence (SAM). Methods and Results Although we found no differences on NO production in females SAM prone (SAMP, aged) compared to SAM resistant (SAMR, young), by either DAF-2 fluorescence or plasmatic nitrite/nitrate (NO2/NO3), in both cases, E2 treatment increased NO production in SAMR but had no effect in SAMP. Those results are in agreement with changes of eNOS protein and gene expression. E2 up-regulated eNOS expression in SAMR but not in SAMP. E2 is also known to increase NO by decreasing its catabolism by superoxide anion (O2-). Interestingly, E2 treatment decreased O2− production in young females, while increased O2− in aged ones. Furthermore, we observed that aging changed expression ratio of estrogen receptors (ERβ/ERα) and levels of DNA methylation. Increased ratio ERβ/ERα in aged females is associated to a lack of estrogen modulation of NO production and with a reversal in its antioxidant effect to a pro-oxidant profile. Conclusions Together, our data suggest that aging has detrimental effects on E2-mediated benefits on NO bioavailability, partially by affecting the ability of E2 to induce up regulation of eNOS and decrease of O2−. These modifications may be associated to aging-mediated modifications on global DNA methylation status, but not to a specific methylation at 5′flanking region of ERα gene. PMID:21966501

  5. New concepts in selenium chemoprevention.

    PubMed

    Ip, Clement; Dong, Yan; Ganther, Howard E

    2002-01-01

    This article highlights some recent advances in selenium cancer chemoprevention research. It has been well documented that the chemical transformation of selenium to a monomethylated metabolite is an important step in achieving cancer prevention. Studies with the rat mammary carcinogenesis model suggested that methylselenocysteine (MSC), a good precursor for generating methylselenol endogenously, is able to block clonal expansion of premalignant lesions in the mammary gland. This finding supports the notion that selenium intervenes at an early stage of carcinogenesis. In addition to decreasing cell proliferation of the transformed colonies in vivo, MSC also enhances apoptosis. These same cellular responses are replicated with human premalignant breast cells grown in culture. cDNA microarray analysis indicated that selenium affects a multitude of molecular targets. Based on this information, a number of signaling pathways are proposed that could potentially provide insight into how selenium might block cell cycle progression and induce cell death.

  6. Groundwater and surface-water interaction, water quality, and processes affecting loads of dissolved solids, selenium, and uranium in Fountain Creek near Pueblo, Colorado, 2012–2014

    USGS Publications Warehouse

    Arnold, L. Rick; Ortiz, Roderick F.; Brown, Christopher R.; Watts, Kenneth R.

    2016-11-28

    In 2012, the U.S. Geological Survey, in cooperation with the Arkansas River Basin Regional Resource Planning Group, initiated a study of groundwater and surface-water interaction, water quality, and loading of dissolved solids, selenium, and uranium to Fountain Creek near Pueblo, Colorado, to improve understanding of sources and processes affecting loading of these constituents to streams in the Arkansas River Basin. Fourteen monitoring wells were installed in a series of three transects across Fountain Creek near Pueblo, and temporary streamgages were established at each transect to facilitate data collection for the study. Groundwater and surface-water interaction was characterized by using hydrogeologic mapping, groundwater and stream-surface levels, groundwater and stream temperatures, vertical hydraulic-head gradients and ratios of oxygen and hydrogen isotopes in the hyporheic zone, and streamflow mass-balance measurements. Water quality was characterized by collecting periodic samples from groundwater, surface water, and the hyporheic zone for analysis of dissolved solids, selenium, uranium, and other selected constituents and by evaluating the oxidation-reduction condition for each groundwater sample under different hydrologic conditions throughout the study period. Groundwater loads to Fountain Creek and in-stream loads were computed for the study area, and processes affecting loads of dissolved solids, selenium, and uranium were evaluated on the basis of geology, geochemical conditions, land and water use, and evapoconcentration.During the study period, the groundwater-flow system generally contributed flow to Fountain Creek and its hyporheic zone (as a single system) except for the reach between the north and middle transects. However, the direction of flow between the stream, the hyporheic zone, and the near-stream aquifer was variable in response to streamflow and stage. During periods of low streamflow, Fountain Creek generally gained flow from

  7. Bioanalytical effect-balance model to determine the bioavailability of organic contaminants in sediments affected by black and natural carbon.

    PubMed

    Bräunig, Jennifer; Tang, Janet Y M; Warne, Michael St J; Escher, Beate I

    2016-08-01

    In sediments several binding phases dictate the fate and bioavailability of organic contaminants. Black carbon (BC) has a high sorptive capacity for organic contaminants and can limit their bioavailability, while the fraction bound to organic carbon (OC) is considered to be readily desorbable and bioavailable. We investigated the bioavailability and mixture toxicity of sediment-associated contaminants by combining different extraction techniques with in vitro bioanalytical tools. Sediments from a harbour with high fraction of BC, and sediments from remote, agricultural and urban areas with lower BC were treated with exhaustive solvent extraction, Tenax extraction and passive sampling to estimate total, bioaccessible and bioavailable fractions, respectively. The extracts were characterized with cell-based bioassays that measure dioxin-like activity (AhR-CAFLUX) and the adaptive stress response to oxidative stress (AREc32). Resulting bioanalytical equivalents, which are effect-scaled concentrations, were applied in an effect-balance model, consistent with a mass balance-partitioning model for single chemicals. Sediments containing BC had most of the bioactivity associated to the BC fraction, while the OC fraction played a role for sediments with lower BC. As effect-based sediment-water distribution ratios demonstrated, most of the bioactivity in the AhR-CAFLUX was attributable to hydrophobic chemicals while more hydrophilic chemicals activated AREc32, even though bioanalytical equivalents in the aqueous phase remained negligible. This approach can be used to understand the fate and effects of mixtures of diverse organic contaminants in sediments that would not be possible if single chemicals were targeted by chemical analysis; and make informed risk-based decisions concerning the management of contaminated sediments.

  8. Modeling the impact of soil aggregate size on selenium immobilization

    NASA Astrophysics Data System (ADS)

    Kausch, M. F.; Pallud, C. E.

    2012-09-01

    Soil aggregates are mm- to cm-sized microporous structures separated by macropores. Whereas fast advective transport prevails in macropores, advection is inhibited by the low permeability of intra-aggregate micropores. This can lead to mass transfer limitations and the formation of aggregate-scale concentration gradients affecting the distribution and transport of redox sensitive elements. Selenium (Se) mobilized through irrigation of seleniferous soils has emerged as a major aquatic contaminant. In the absence of oxygen, the bioavailable oxyanions selenate, Se(VI), and selenite, Se(IV), can be microbially reduced to solid, elemental Se, Se(0), and anoxic microzones within soil aggregates are thought to promote this process in otherwise well aerated soils. To evaluate the impact of soil aggregate size on selenium retention, we developed a dynamic 2-D reactive transport model of selenium cycling in a single idealized aggregate surrounded by a macropore. The model was developed based on flow-through-reactor experiments involving artificial soil aggregates (diameter: 2.5 cm) made of sand and containing Enterobacter cloacae SLD1a-1 that reduces Se(VI) via Se(IV) to Se(0). Aggregates were surrounded by a constant flow providing Se(VI) and pyruvate under oxic or anoxic conditions. In the model, reactions were implemented with double-Monod rate equations coupled to the transport of pyruvate, O2, and Se-species. The spatial and temporal dynamics of the model were validated with data from experiments and predictive simulations were performed covering aggregate sizes between 1 and 2.5 cm diameter. Simulations predict that selenium retention scales with aggregate size. Depending on O2, Se(VI), and pyruvate concentrations, selenium retention was 4-23 times higher in 2.5-cm-aggregates compared to 1-cm-aggregates. Under oxic conditions, aggregate size and pyruvate-concentrations were found to have a positive synergistic effect on selenium retention. Promoting soil aggregation on

  9. Modeling the impact of soil aggregate size on selenium immobilization

    NASA Astrophysics Data System (ADS)

    Kausch, M. F.; Pallud, C. E.

    2013-03-01

    Soil aggregates are mm- to cm-sized microporous structures separated by macropores. Whereas fast advective transport prevails in macropores, advection is inhibited by the low permeability of intra-aggregate micropores. This can lead to mass transfer limitations and the formation of aggregate scale concentration gradients affecting the distribution and transport of redox sensitive elements. Selenium (Se) mobilized through irrigation of seleniferous soils has emerged as a major aquatic contaminant. In the absence of oxygen, the bioavailable oxyanions selenate, Se(VI), and selenite, Se(IV), can be microbially reduced to solid, elemental Se, Se(0), and anoxic microzones within soil aggregates are thought to promote this process in otherwise well-aerated soils. To evaluate the impact of soil aggregate size on selenium retention, we developed a dynamic 2-D reactive transport model of selenium cycling in a single idealized aggregate surrounded by a macropore. The model was developed based on flow-through-reactor experiments involving artificial soil aggregates (diameter: 2.5 cm) made of sand and containing Enterobacter cloacae SLD1a-1 that reduces Se(VI) via Se(IV) to Se(0). Aggregates were surrounded by a constant flow providing Se(VI) and pyruvate under oxic or anoxic conditions. In the model, reactions were implemented with double-Monod rate equations coupled to the transport of pyruvate, O2, and Se species. The spatial and temporal dynamics of the model were validated with data from experiments, and predictive simulations were performed covering aggregate sizes 1-2.5 cm in diameter. Simulations predict that selenium retention scales with aggregate size. Depending on O2, Se(VI), and pyruvate concentrations, selenium retention was 4-23 times higher in 2.5 cm aggregates compared to 1 cm aggregates. Under oxic conditions, aggregate size and pyruvate concentrations were found to have a positive synergistic effect on selenium retention. Promoting soil aggregation on

  10. 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

  11. Variations in the accumulation, localization and rate of metabolization of selenium in mature Zea mays plants supplied with selenite or selenate.

    PubMed

    Longchamp, Mélanie; Castrec-Rouelle, Maryse; Biron, Philippe; Bariac, Thierry

    2015-09-01

    Quantification of selenium bioavailability from foods is a key challenge following the discovery of the antioxidant role of this micronutrient in human health. This study presents the uptake, accumulation and rate of metabolization in mature Zea mays plants grown in hydroponic solution supplemented with selenate or selenite. Selenium content was lower in plants supplemented with selenate and accumulated mainly in the leaves compared with selenite-treated plants where the selenium was retained in the roots. Selenite-treated grains accumulated more selenium. Selenate was metabolized less than selenite in whole plants, but in grains selenium was present exclusively as organic selenium compounds. For humans, the bioavailability of organic selenium was evaluated at 90% compared with only 50% for inorganic forms. Our results show that the potential for selenium bioavailability is increased with selenite treatment.

  12. Iron concentration, bioavailability, and nutritional quality of polished rice affected by different forms of foliar iron fertilizer.

    PubMed

    He, Wanling; Shohag, M J I; Wei, Yanyan; Feng, Ying; Yang, Xiaoe

    2013-12-15

    The present study compared the effects of four different forms of foliar iron (Fe) fertilizers on Fe concentration, bioavailability and nutritional quality of polished rice. The results showed that foliar fertilisation at the anthesis stage was an effective way to promote Fe concentration and bioavailability of polished rice, especially in case of DTPA-Fe. Compared to the control, foliar application of DTPA-Fe increased sulphur concentration and the nutrition promoter cysteine content, whereas decreased phosphorus concentration and the antinutrient phytic acid content of polished rice, as a result increased 67.2% ferrtin formation in Caco-2 cell. Moreover, foliar DTPA-Fe application could maintain amylase, protein and minerals quality of polished rice. According to the current study, DTPA-Fe is recommended as an excellent foliar Fe form for Fe biofortification program.

  13. Intestinal nematodes affect selenium bioaccumulation, oxidative stress biomarkers, and health parameters in juvenile rainbow trout (Oncorhynchus mykiss).

    PubMed

    Hursky, Olesya; Pietrock, Michael

    2015-02-17

    In environmental studies, parasites are often seen as a product of enhanced host susceptibility due to exposure to one or several stressors, whereas potential consequences of infections on host responses are often overlooked. Therefore, the present study focused on effects of parasitism on bioaccumulation of selenium (Se) in rainbow trout (Oncorhynchus mykiss). Joint effects of biological (parasite) and chemical (Se) stressors on biomarkers of oxidative stress (glutathione-S-transferase (GST), superoxide dismutase (SOD)), and fish health (condition factor (K), hepatosomatic index (HSI), gross energy) were also examined. Fish of the control group received uncontaminated food, while test fish, either experimentally infected with the nematode Raphidascaris acus or not, were exposed to dietary selenomethionine (Se-Met) at an environmentally relevant dose over 7 weeks. Selenium bioaccumulation by the parasite was low relative to its host, and parasitized trout showed slowed Se accumulation in the muscle as compared to uninfected fish. Furthermore, GST and SOD activities of trout exposed to both Se-Met and parasites were generally significantly lower than in fish exposed to Se-Met alone. Gross energy concentrations, but not K or HSI, were reduced in fish exposed to both Se-Met and R. acus. Together the experiment strongly calls for consideration of parasites when interpreting effects of pollutants on aquatic organisms in field investigations.

  14. Selenium and anticarcinogenesis: underlying mechanisms.

    PubMed

    Jackson, Matthew I; Combs, Gerald F

    2008-11-01

    To discuss recent research related to anticarcinogenic mechanisms of selenium action in light of the underlying chemical/biochemical functions of the selenium species, likely to be executors of those effects. Recent studies in a variety of model systems have increased the understanding of the anticarcinogenic mechanisms of selenium compounds. These include effects on gene expression, DNA damage and repair, signaling pathways, regulation of cell cycle and apoptosis, metastasis and angiogenesis. These effects would appear to be related to the production of reactive oxygen species produced by the redox cycling, modification of protein-thiols and methionine mimicry. Three principle selenium metabolites appear to execute these effects: hydrogen selenide, methylselenol and selenomethionine. The fact that various selenium compounds can be metabolized to one or more of these species but differ in anticarcinogenic activity indicates competing pathways of their metabolic and chemical/biochemical disposition. Increasing knowledge of selenoprotein polymorphisms has shown that at least some are related to cancer risk and may affect carcinogenesis indirectly by influencing selenium metabolism. The anticarcinogenic effects of selenium compounds constitute intermediate mechanisms with several underlying chemical/biochemical mechanisms such as redox cycling, alteration of protein-thiol redox status and methionine mimicry.

  15. 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.

  16. Selenium and trace element mobility affected by periodic displacement of stratification in the Great Salt Lake, Utah.

    PubMed

    Beisner, Kimberly; Naftz, David L; Johnson, William P; Diaz, Ximena

    2009-09-15

    The Great Salt Lake (GSL) is a unique ecosystem in which trace element activity cannot be characterized by standard geochemical parameters due to the high salinity. Movement of selenium and other trace elements present in the lake bed sediments of GSL may occur due to periodic stratification displacement events or lake bed exposure. The water column of GSL is complicated by the presence of a chemocline persistent over annual to decadal time scales. The water below the chemocline is referred to as the deep brine layer (DBL), has a high salinity (16.5 to 22.9%) and is anoxic. The upper brine layer (UBL) resides above the chemocline, has lower salinity (12.6 to 14.7%) and is oxic. Displacement of the DBL may involve trace element movement within the water column due to changes in redox potential. Evidence of stratification displacement in the water column has been observed at two fixed stations on the lake by monitoring vertical water temperature profiles with horizontal and vertical velocity profiles. Stratification displacement events occur over periods of 12 to 24h and are associated with strong wind events that can produce seiches within the water column. In addition to displacement events, the DBL shrinks and expands in response to changes in the lake surface area over a period of months. Laboratory tests simulating the observed sediment re-suspension were conducted over daily, weekly and monthly time scales to understand the effect of placing anoxic bottom sediments in contact with oxic water, and the associated effect of trace element desorption and (or) dissolution. Results from the laboratory simulations indicate that a small percentage (1%) of selenium associated with anoxic bottom sediments is periodically solubilized into the UBL where it potentially can be incorporated into the biota utilizing the oxic part of GSL.

  17. Selenium and trace element mobility affected by periodic displacement of stratification in the Great Salt Lake, Utah

    USGS Publications Warehouse

    Beisner, K.; Naftz, D.L.; Johnson, W.P.; Diaz, X.

    2009-01-01

    The Great Salt Lake (GSL) is a unique ecosystem in which trace element activity cannot be characterized by standard geochemical parameters due to the high salinity. Movement of selenium and other trace elements present in the lake bed sediments of GSL may occur due to periodic stratification displacement events or lake bed exposure. The water column of GSL is complicated by the presence of a chemocline persistent over annual to decadal time scales. The water below the chemocline is referred to as the deep brine layer (DBL), has a high salinity (16.5 to 22.9%) and is anoxic. The upper brine layer (UBL) resides above the chemocline, has lower salinity (12.6 to 14.7%) and is oxic. Displacement of the DBL may involve trace element movement within the water column due to changes in redox potential. Evidence of stratification displacement in the water column has been observed at two fixed stations on the lake by monitoring vertical water temperature profiles with horizontal and vertical velocity profiles. Stratification displacement events occur over periods of 12 to 24 h and are associated with strong wind events that can produce seiches within the water column. In addition to displacement events, the DBL shrinks and expands in response to changes in the lake surface area over a period of months. Laboratory tests simulating the observed sediment re-suspension were conducted over daily, weekly and monthly time scales to understand the effect of placing anoxic bottom sediments in contact with oxic water, and the associated effect of trace element desorption and (or) dissolution. Results from the laboratory simulations indicate that a small percentage (1%) of selenium associated with anoxic bottom sediments is periodically solubilized into the UBL where it potentially can be incorporated into the biota utilizing the oxic part of GSL.

  18. Forms of selenium affect its transport, uptake and glutathione peroxidase activity in the Caco-2 cell model.

    PubMed

    Wang, Yanbo; Fu, Linglin

    2012-10-01

    The experiment was designed to investigate the effect of selenium (Se) chemical forms (sodium selenite, selenium nanoparticle [nano-Se] and selenomethionine) on the transport, uptake and glutathione peroxidase (GSH-Px) activity in the Caco-2 cell model. The transport and uptake of different forms of Se (0.1 μmol l(-1)) across the Caco-2 cell monolayer were carried out in two directions (apical [AP] to basolateral [BL] and BL to AP) for 2 h, respectively, and the apparent permeability coefficient (P(app)), transport efficiency and uptake efficiency were all calculated. In the present study, the transport and uptake of three forms of Se were time-dependent both in AP to BL and BL to AP directions. By the end of 2 h, the transport efficiencies of selenomethionine and nano-Se were higher than that of sodium selenite (P<0.05). The highest uptake efficiency (P<0.05) was observed in cells treated with nano-Se and significant difference (P<0.05) was also observed between the cells incubated with sodium selenite and selenomethionine. As for the P(app), sodium selenite (P<0.05) had the lowest values compared with that of selenomethionine and nano-Se, in both AP-BL and BL-AP. However, no significant differences were observed in GSH-Px activities. These results indicated that the efficiency of Se in the Caco-2 cells varied with its chemical forms, which might be associated with the differences in Se transport and uptake.

  19. Factors affecting the bioavailability of soy isoflavones in humans after ingestion of physiologically relevant levels from different soy foods.

    PubMed

    Cassidy, Aedin; Brown, Jonathan E; Hawdon, Anne; Faughnan, Marian S; King, Laurence J; Millward, Joe; Zimmer-Nechemias, Linda; Wolfe, Brian; Setchell, Kenneth D R

    2006-01-01

    The precise role that isoflavones play in the health-related effects of soy foods, and their potential for adverse effects are controversial. This may be due in part to a lack of basic knowledge regarding their bioavailability and metabolism, particularly as it relates to the soy source. To date, there is little information concerning possible differences in the bioavailability of isoflavones derived from natural soy foods consumed at physiologically relevant intakes and whether age- or gender-related differences influence that bioavailability. In the current study of healthy adults [premenopausal (n = 21) and postmenopausal (n = 17) women and a group of men (n = 21)], we examined the effect of age, gender, and the food matrix on the bioavailability of isoflavones for both the aglycon and glucoside forms that are naturally present in 3 different soy foods, soy milk, textured vegetable protein, and tempeh. The study was designed as a random crossover trial so that all individuals received each of the 3 foods. The dose of isoflavones administered to each individual as a single bolus dose was 0.44 mg/kg body weight. Pharmacokinetic parameters were normalized to mg of each isoflavone ingested per kilogram body weight to account for differences in daidzein and genistein content between the diets. Serum isoflavone concentrations in all individuals and groups increased rapidly after the ingestion of each soy food; as expected, genistein concentrations exceeded daidzein concentrations in serum. In this small study, gender differences in peak concentrations of daidzein were observed, with higher levels attained in women. Consumption of tempeh (mainly isoflavone aglycon) resulted in higher serum peak levels of both daidzein (P < 0.001) and genistein (P < 0.01) and the associated area under the curve (P < 0.001 and P < 0.03, respectively) compared with textured vegetable protein (predominantly isoflavone glucosides). However, soy milk was absorbed faster and peak levels of

  20. 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

  1. 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.

  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. Redox regulation of protein tyrosine phosphatase 1B by manipulation of dietary selenium affects the triglyceride concentration in rat liver.

    PubMed

    Mueller, Andreas S; Klomann, Sandra D; Wolf, Nicole M; Schneider, Sandra; Schmidt, Rupert; Spielmann, Julia; Stangl, Gabriele; Eder, Klaus; Pallauf, Josef

    2008-12-01

    Protein tyrosine phosphatase 1B (PTP1B) is a key enzyme in the counter-regulation of insulin signaling and in the stimulation of fatty acid synthesis. Selenium (Se), via the activities of glutathione peroxidase (GPx) and thioredoxin reductase (TrxR), is involved in the removal of H(2)O(2) and organic peroxides, which are critical compounds in the modulation of PTP1B activity via glutathionylation. Our study with growing rats investigated how the manipulation of dietary Se concentration influences the regulation of PTP1B and lipogenic effects mediated by PTP1B. Weanling albino rats were divided into 3 groups of 10. The negative control group (NC) was fed a Se-deficient diet for 8 wk. Rats in groups Se75 and Se150 received diets supplemented with 75 or 150 microg Se/kg. Se supplementation of the rats strongly influenced expression and activity of the selenoenzymes cytosolic GPx, plasma GPx, phospholipidhydroperoxide GPx, and cytosolic TrxR, and liver PTP1B. Liver PTP1B activity was significantly higher in groups Se75 and Se150 than in the NC group and this was attributed to a lowered inhibition of the enzyme by glutathionylation. The increased liver PTP1B activity in groups Se75 and Se150 resulted in 1.1- and 1.4-fold higher liver triglyceride concentrations than in the NC rats. The upregulation of the sterol regulatory element binding protein-1c and of fatty acid synthase, 2 PTP1B targets, provided a possible explanation for the lipogenic effect of PTP1B due to the manipulation of dietary Se. We therefore conclude that redox-regulated proteins, such as PTP1B, represent important interfaces between dietary antioxidants such as Se and the regulation of metabolic processes.

  4. Selenium accumulation and selenium-salt co-tolerance in five grass species. [Festuca arundinaceae; Agropyron deserorum; Buchloe dactyloides; Agrostis stolonifera; Cynodon dactylon

    SciTech Connect

    Wu, L.; Huang, Z.; Burau, R.G.

    1987-04-01

    Five grass species including Tall fescue (Festuca arundinaceae Schred), Crested wheatgrass (Agropyron deserorum Fisch), Buffalo grass (Buchlor dactyloides (Nutt.) Engelm.), Seaside bentgrass (Agrostis stolonifera L.) and Bermuda grass (Cynodon dactylon (L.) Pers., Syn.) were examined for selenium and salt tolerance and selenium accumulation under solution culture conditions. Distinct differences in both selenium and salt tolerance were detected among the five species, but no direct association between selenium and salt resistance was found. Tall fescue displayed considerable tolerance under 1 ppm selenium and 100 mM salt treatment. Combined selenium and salt treatment revealed that selenium uptake was increased by the incorporation of salt in the culture solution. However, salt uptake was not significantly affected by the presence of selenium in the culture solution. At moderate toxic levels of selenium, the species with greater tolerance accumulated less selenium than did the less tolerant species.

  5. Selenium nanoparticles as a nutritional supplement.

    PubMed

    Skalickova, Sylvie; Milosavljevic, Vedran; Cihalova, Kristyna; Horky, Pavel; Richtera, Lukas; Adam, Vojtech

    2017-01-01

    Selenium is an essential trace element in the diet, required for maintenance of health and growth; however, its toxicity could cause serious damage depending on dose and chemical form. Selenium nanoparticles (SeNPs) represent what we believe to be a novel prospect for nutritional supplementation because of their lower toxicity and ability to gradually release selenium after ingestion. In this review, we discuss various forms and types of SeNPs, as well as the way they are synthesized. We also discuss absorption and bioavailability of nanoparticles within the organism. SeNPs demonstrate anticancer and antimicrobial properties that may contribute to human health, not only as dietary supplements, but also as therapeutic agents. Copyright © 2016 Elsevier Inc. All rights reserved.

  6. Bioavailable concentrations of germanium and rare earth elements in soil as affected by low molecular weight organic acids and root exudates

    NASA Astrophysics Data System (ADS)

    Wiche, Oliver; Székely, Balázs; Kummer, Nicolai-Alexeji; Heinemann, Ute; Tesch, Silke; Heilmeier, Hermann

    2014-05-01

    , lanthan, neodymium, gadolinium and erbium in the rhizosphere and therefore the enhancement of bioavailability of the mentioned elements to plants. Based on the suction cup experiment we conclude that in vertical soil profile the bioavailable germanium is heavily affected by the activity of exudates, as the complexation processes of germanium take place at the root zone and below affected by the interplay of the infiltration of citric acid solutions and the actually produced exudates. These studies have been carried out in the framework of the PhytoGerm project, financed by the Federal Ministry of Education and Research, Germany. BS contributed as an Alexander von Humboldt Research Fellow. The authors are grateful to students and laboratory assistants contributing in the field work and sample preparation.

  7. Selenium species in selenium fortified dietary supplements.

    PubMed

    Niedzielski, Przemyslaw; Rudnicka, Monika; Wachelka, Marcin; Kozak, Lidia; Rzany, Magda; Wozniak, Magdalena; Kaskow, Zaneta

    2016-01-01

    This article presents a study of dietary supplements available on the Polish market. The supplements comprised a large group of products with selenium content declared by the producer. The study involved determination of dissolution time under different conditions and solubility as well as content and speciation of selenium. The total content was determined as well as organic selenium and the inorganic forms Se(IV) and Se(VI). The organic selenium content was calculated as the difference between total Se and inorganic Se. The values obtained were compared with producers' declarations. The work is the first such study of selenium supplements available on the market of an EU Member State.

  8. Genetic variability for iron and zinc as well as antinutrients affecting bioavailability in black gram (Vigna mungo (L.) Hepper).

    PubMed

    Singh, Jagdish; Kanaujia, Rajani; Srivastava, A K; Dixit, G P; Singh, N P

    2017-03-01

    The mineral content of pulses is generally high, but the bioavailability is poor due to the presence of phytate and polyphenols which inhibits Fe absorption. In the present study, the genetic variability and heritability for seed Fe and Zn content was studied. The effect of genotypes was significant for all the quality traits indicating presence of enough variability among the blackgram genotypes for the traits. The Fe content in 26 blackgram genotypes ranged from 71.02 to 100.20 ppm, whereas Zn content ranged from 18.93 to 60.58 ppm. Maximum Fe as well as Zn was recorded in genotype SHEKHAR 2 (100.2 and 60.58 ppm respectively). The Phytic acid and polyphenol content among genotypes varied significantly and it ranged from 0.06-0.37% to 5.88-9.03 mg/g, respectively. High phytic acid content was recorded in black gram genotypes COBG 653, Nodai Urd, NP 03 and PKG U 03, whereas high polyphenol content was recorded in PU 31, IPU 99-200, PDU 1 and YAKUBPUR 2. Blackgram genotype COBG 653 had high phytic acid but low polyphenol content. The genotype × year interaction was significant for all the traits under study which indicates differential reaction to the expression of quality characters over years. Fe content in blackgram genotypes showed significant positive phenotypic correlation with Zn content while at genotypic level in addition to Zn, it showed positive correlation with phytic acid and polyphenol content as well. This indicates that although the traits are genotypically correlated, the expression is masked by the environmental influence. This is further exhibited from low heritability estimates for phytic acid and polyphenol content among the genotypes.

  9. The Freundlich adsorption isotherm constants and prediction of phosphorus bioavailability as affected by different phosphorus sources in two Kansas soils.

    PubMed

    Shafqat, Mustafa N; Pierzynski, Gary M

    2014-03-01

    Phosphorus (P) adsorption onto soil constituents influences P bioavailability from both agronomic and environmental perspectives. In this study, the P availability from different P sources along with utility of Freundlich adsorption coefficients on the predictability of various crop growth parameters were assessed. Two soils were amended with 150mgPkg(-1) each from six different P sources comprised of manures from two types of ruminants animals, three types of monogastric animals, and inorganic P fertilizer. Corn (Zea mays) was grown and harvested seven times under greenhouse conditions to remove P from the P amended treatments. The application of all P sources reduced the value of Freundlich K and increased the value of Freundlich 1/n and equilibrium P concentration (EPC0) in both soils compared to the un-amended control before cropping. The swine (Sus scrofa) manure (HM) resulted in significant smaller values of Freundlich K and larger values of 1/n in the P deficient Eram-Lebo soil compared to other P sources while, the opposite was true for the turkey (Meleagris gallopava) litter (TL) in the Ulysses soil. The corn biomass, tissue P concentration and P uptake were significantly influenced by all P sources during the first harvest and the total P uptake during seven harvests in both soils compared to the control treatment. Both Freundlich coefficients had strong relationships with the aforementioned corn parameters in the P deficient Eram-Lebo soil while, strength of the association was weak or missing in the Ulysses soil which had optimum levels of antecedent P. Copyright © 2013 Elsevier Ltd. All rights reserved.

  10. Synthesis and stabilization of selenium nanoparticles on cellulose nanocrystal

    SciTech Connect

    Shin, Yongsoon; Blackwood, Jade M.; Bae, In-Tae; Arey, Bruce W.; Exarhos, Gregory J.

    2007-08-01

    Selenium nanoparticles of 10-20 nm in diameter have been prepared using cellulose nanocrystal (CNXL) as a reducing and structure-directing agent under hydrothermal conditions. Na2SeO3 was reduced to form elemental selenium nanoparticles under hydrothermal conditions. During the hydrothermal process (120-160 oC), CNXL rods were mainly maintained and selenium nanoparticles were interfacially bound to CNXL surface. The reaction temperature affects the sizes of interfacially bound selenium nanoparticles. X-ray diffraction (XRD), field emission scanning electron microscope (FESEM), and transmission electron microscope (TEM) were employed to characterize interfacially bound selenium nanoparticles on CNXL surface.

  11. Selenium Supplementation Affects Physiological and Biochemical Processes to Improve Fodder Yield and Quality of Maize (Zea mays L.) under Water Deficit Conditions

    PubMed Central

    Nawaz, Fahim; Naeem, Muhammad; Ashraf, Muhammad Y.; Tahir, Muhammad N.; Zulfiqar, Bilal; Salahuddin, Muhammad; Shabbir, Rana N.; Aslam, Muhammad

    2016-01-01

    Climate change is one of the most complex challenges that pose serious threats to livelihoods of poor people who rely heavily on agriculture and livestock particularly in climate-sensitive developing countries of the world. The negative effects of water scarcity, due to climate change, are not limited to productivity food crops but have far-reaching consequences on livestock feed production systems. Selenium (Se) is considered essential for animal health and has also been reported to counteract various abiotic stresses in plants, however, understanding of Se regulated mechanisms for improving nutritional status of fodder crops remains elusive. We report the effects of exogenous selenium supply on physiological and biochemical processes that may influence green fodder yield and quality of maize (Zea mays L.) under drought stress conditions. The plants were grown in lysimeter tanks under natural conditions and were subjected to normal (100% field capacity) and water stress (60% field capacity) conditions. Foliar spray of Se was carried out before the start of tasseling stage (65 days after sowing) and was repeated after 1 week, whereas, water spray was used as a control. Drought stress markedly reduced the water status, pigments and green fodder yield and resulted in low forage quality in water stressed maize plants. Nevertheless, exogenous Se application at 40 mg L-1 resulted in less negative leaf water potential (41%) and enhanced relative water contents (30%), total chlorophyll (53%), carotenoid contents (60%), accumulation of total free amino acids (40%) and activities of superoxide dismutase (53%), catalase (30%), peroxidase (27%), and ascorbate peroxidase (27%) with respect to control under water deficit conditions. Consequently, Se regulated processes improved fodder yield (15%) and increased crude protein (47%), fiber (10%), nitrogen free extract (10%) and Se content (36%) but did not affect crude ash content in water stressed maize plants. We propose that Se

  12. Selenium Supplementation Affects Physiological and Biochemical Processes to Improve Fodder Yield and Quality of Maize (Zea mays L.) under Water Deficit Conditions.

    PubMed

    Nawaz, Fahim; Naeem, Muhammad; Ashraf, Muhammad Y; Tahir, Muhammad N; Zulfiqar, Bilal; Salahuddin, Muhammad; Shabbir, Rana N; Aslam, Muhammad

    2016-01-01

    Climate change is one of the most complex challenges that pose serious threats to livelihoods of poor people who rely heavily on agriculture and livestock particularly in climate-sensitive developing countries of the world. The negative effects of water scarcity, due to climate change, are not limited to productivity food crops but have far-reaching consequences on livestock feed production systems. Selenium (Se) is considered essential for animal health and has also been reported to counteract various abiotic stresses in plants, however, understanding of Se regulated mechanisms for improving nutritional status of fodder crops remains elusive. We report the effects of exogenous selenium supply on physiological and biochemical processes that may influence green fodder yield and quality of maize (Zea mays L.) under drought stress conditions. The plants were grown in lysimeter tanks under natural conditions and were subjected to normal (100% field capacity) and water stress (60% field capacity) conditions. Foliar spray of Se was carried out before the start of tasseling stage (65 days after sowing) and was repeated after 1 week, whereas, water spray was used as a control. Drought stress markedly reduced the water status, pigments and green fodder yield and resulted in low forage quality in water stressed maize plants. Nevertheless, exogenous Se application at 40 mg L(-1) resulted in less negative leaf water potential (41%) and enhanced relative water contents (30%), total chlorophyll (53%), carotenoid contents (60%), accumulation of total free amino acids (40%) and activities of superoxide dismutase (53%), catalase (30%), peroxidase (27%), and ascorbate peroxidase (27%) with respect to control under water deficit conditions. Consequently, Se regulated processes improved fodder yield (15%) and increased crude protein (47%), fiber (10%), nitrogen free extract (10%) and Se content (36%) but did not affect crude ash content in water stressed maize plants. We propose that

  13. 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

  14. Hair sampling location in harbor seals (Phoca vitulina) affects selenium and mercury concentrations: implications for study design of trace element determination in pinnipeds.

    PubMed

    McHuron, Elizabeth A; Harvey, James T; Castellini, J Margaret; O'Hara, Todd M

    2012-11-01

    Hair is used to determine trace elements exposure and status of pinnipeds because it is an excretory route for many elements and can be collected non-lethally. Despite increased use, there have been few studies on how sampling designs and procedures (e.g., hair type, collection site) affect results. The objective of this study was to determine whether concentrations of an essential (selenium; Se) and non-essential element (mercury; Hg) differed between hair samples collected from two body locations on harbor seals (Phoca vitulina). Concentrations of Se and total Hg (THg) differed between mid-dorsal midline and neck samples, and although the absolute differences were relatively small (Δ(absolute) Se = 0.69 μg g(-1), Δ(absolute) THg = 2.86 μg g(-1)), the relative differences were large (Δ(relative) Se = 49%, Δ(relative) THg = 17%). These differences highlight the need to standardize the collection site for trace element determination in pinnipeds.

  15. 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

    2014-08-01

    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. Copyright AULA MEDICA EDICIONES 2014. Published by AULA MEDICA. All rights reserved.

  16. Arsenic and selenium in microbial metabolism

    USGS Publications Warehouse

    Stolz, John F.; Basu, Partha; Santini, Joanne M.; Oremland, Ronald S.

    2006-01-01

    Arsenic and selenium are readily metabolized by prokaryotes, participating in a full range of metabolic functions including assimilation, methylation, detoxification, and anaerobic respiration. Arsenic speciation and mobility is affected by microbes through oxidation/reduction reactions as part of resistance and respiratory processes. A robust arsenic cycle has been demonstrated in diverse environments. Respiratory arsenate reductases, arsenic methyltransferases, and new components in arsenic resistance have been recently described. The requirement for selenium stems primarily from its incorporation into selenocysteine and its function in selenoenzymes. Selenium oxyanions can serve as an electron acceptor in anaerobic respiration, forming distinct nanoparticles of elemental selenium that may be enriched in (76)Se. The biogenesis of selenoproteins has been elucidated, and selenium methyltransferases and a respiratory selenate reductase have also been described. This review highlights recent advances in ecology, biochemistry, and molecular biology and provides a prelude to the impact of genomics studies.

  17. [Selenium tolerance of yeasts].

    PubMed

    Golubev, V I; Golubev, N V

    2002-01-01

    Selenium tolerance of yeasts widely varies: the growth of some yeasts can be inhibited by a selenium concentration as low as 10(-4) M, whereas others can grow in the presence of 10(-1) M selenium. Homogeneous yeast taxa are characterized by a certain level of selenium tolerance, and heterogeneous taxa show a variable level of tolerance to selenium. In general, ascomycetous yeasts are more tolerant to selenium than basidiomycetous yeasts. Among the ascomycetous yeasts, the genera Dekkera and Schizosaccharomyces exhibited the lowest and the species Candida maltosa, Hanseniaspora valbyensis, Kluyveromyces marxianus, and Yarrowia lipolytica the highest tolerance to selenium. Among the basidiomycetous yeasts, the genera Bullera, Cryptococcus, and Holtermannia showed the lowest and the species Cryptococcus curvatus, Cr. humicola, and Trichosporon spp. the highest tolerance to selenium. The selenium tolerance of yeasts depends on the composition of the growth medium, in particular, on the presence of sulfate, sulfur-containing amino acids, and glutamine in the medium.

  18. Microbial Transformations of Selenium Species of Relevance to Bioremediation

    PubMed Central

    Eswayah, Abdurrahman S.; Smith, Thomas J.

    2016-01-01

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

  19. 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. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

  20. Elemental selenium at nano size possesses lower toxicity without compromising the fundamental effect on selenoenzymes: comparison with selenomethionine in mice.

    PubMed

    Wang, Huali; Zhang, Jinsong; Yu, Hanqing

    2007-05-15

    Glutathione peroxidase and thioredoxin reductase are major selenoenzymes through which selenium exerts powerful antioxidant effects. Selenium also elicits pro-oxidant effects at toxic levels. The antioxidant and pro-oxidant effects, or bioavailability and toxicity, of selenium depend on its chemical form. Selenomethionine is considered to be the most appropriate supplemental form due to its excellent bioavailability and lower toxicity compared to various selenium compounds. The present studies reveal that, compared with selenomethionine, elemental selenium at nano size (Nano-Se) possesses equal efficacy in increasing the activities of glutathione peroxidase and thioredoxin reductase but has much lower toxicity as indicated by median lethal dose, acute liver injury, and short-term toxicity. Our results suggest that Nano-Se can serve as an antioxidant with reduced risk of selenium toxicity.

  1. Mapping mine wastes and analyzing areas affected by selenium-rich water runoff in southeast Idaho using AVIRIS imagery and digital elevation data

    USGS Publications Warehouse

    Mars, J.C.; Crowley, J.K.

    2003-01-01

    Remotely sensed hyperspectral and digital elevation data from southeastern Idaho are combined in a new method to assess mine waste contamination. Waste rock from phosphorite mining in the area contains selenium, cadmium, vanadium, and other metals. Toxic concentrations of selenium have been found in plants and soils near some mine waste dumps. Eighteen mine waste dumps and five vegetation cover types in the southeast Idaho phosphate district were mapped by using Airborne Visible-Infrared Imaging Spectrometer (AVIRIS) imagery and field data. The interaction of surface water runoff with mine waste was assessed by registering the AVIRIS results to digital elevation data, enabling determinations of (1) mine dump morphologies, (2) catchment watershed areas above each mine dump, (3) flow directions from the dumps, (4) stream gradients, and (5) the extent of downstream wetlands available for selenium absorption. Watersheds with the most severe selenium contamination, such as the South Maybe Canyon watershed, are associated with mine dumps that have large catchment watershed areas, high stream gradients, a paucity of downstream wetlands, and dump forms that tend to obstruct stream flow. Watersheds associated with low concentrations of dissolved selenium, such as Angus Creek, have mine dumps with small catchment watershed areas, low stream gradients, abundant wetlands vegetation, and less obstructing dump morphologies. ?? 2002 Elsevier Science Inc. All rights reserved.

  2. Aquatic Life Criterion - Selenium

    EPA Pesticide Factsheets

    Documents pertaining to the 2016 Acute and Chronic Ambient Aquatic Life Water Quality Criteria for Selenium (Freshwater). These documents include what the safe levels of Selenium are in water for the majority of species.

  3. [Selenium deficiency in pregnancy?].

    PubMed

    Lechner, W; Jenewein, I; Ritzberger, G; Sölder, E; Waitz-Penz, A; Schirmer, M; Abfalter, E

    1990-07-15

    Selenium content was investigated by atomic absorbtion spectroscopy in 32 normal pregnant women in the 38th-42, week of pregnancy. In congruence with other investigations from middle and northern Europe, selenium deficiency was stated in all of the patients.

  4. 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)

  5. 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)

  6. Selenium in diet

    MedlinePlus

    ... this page: //medlineplus.gov/ency/article/002414.htm Selenium in diet To use the sharing features on this page, please enable JavaScript. Selenium is an essential trace mineral. This means your ...

  7. 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)

  8. 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)

  9. Selenoprotein Gene Expression in Thyroid and Pituitary of Young Pigs Is Not Affected by Dietary Selenium Deficiency or Excess1–3

    PubMed Central

    Zhou, Ji-Chang; Zhao, Hua; Li, Jun-Gang; Xia, Xin-Jie; Wang, Kang-Ning; Zhang, Ya-Jun; Liu, Yan; Zhao, Ying; Lei, Xin Gen

    2009-01-01

    Expression and function of selenoproteins in endocrine tissues remain unclear, largely due to limited sample availability. Pigs have a greater metabolic similarity and tissue size than rodents as a model of humans for that purpose. We conducted 2 experiments: 1) we cloned 5 novel porcine selenoprotein genes; and 2) we compared the effects of dietary selenium (Se) on mRNA levels of 12 selenoproteins, activities of 4 antioxidant enzymes, and Se concentrations in testis, thyroid, and pituitary with those in liver of pigs. In Experiment 1, porcine Gpx2, Sephs2, Sep15, Sepn1, and Sepp1 were cloned and demonstrated 84–94% of coding sequence homology to human genes. In Experiment 2, weanling male pigs (n = 30) were fed a Se-deficient (0.02 mg Se/kg) diet added with 0, 0.3, or 3.0 mg Se/kg as Se-enriched yeast for 8 wk. Although dietary Se resulted in dose-dependent increases (P < 0.05) in Se concentrations and GPX activities in all 4 tissues, it did not affect the mRNA levels of any selenoprotein gene in thyroid or pituitary. Testis mRNA levels of Txnrd1 and Sep15 were decreased (P < 0.05) by increasing dietary Se from 0.3 to 3.0 mg/kg. Comparatively, expressions of Gpx2, Gpx4, Dio3, and Sep15 were high in pituitary and Dio1, Sepp1, Sephs2, and Gpx1 were high in liver. In conclusion, the mRNA abundances of the 12 selenoprotein genes in thyroid and pituitary of young pigs were resistant to dietary Se deficiency or excess. PMID:19357213

  10. Prolonged Dietary Selenium Deficiency or Excess Does Not Globally Affect Selenoprotein Gene Expression and/or Protein Production in Various Tissues of Pigs123

    PubMed Central

    Liu, Yan; Zhao, Hua; Zhang, Qiaoshan; Tang, Jiayong; Li, Ke; Xia, Xin-Jie; Wang, Kang-Ning; Li, Kui; Lei, Xin Gen

    2012-01-01

    We previously determined the effects of dietary selenium (Se) deficiency or excess on mRNA abundance of 12 selenoprotein genes in pig tissues. In this study, we determined the effect of dietary Se on mRNA levels of the remaining porcine selenoprotein genes along with protein production of 4 selenoproteins (Gpx1, Sepp1, Selh, and Sels) and body glucose homeostasis. Weanling male pigs (n = 24) were fed a Se-deficient (<0.02 mg Se/kg), basal diet supplemented with 0, 0.3, or 3.0 mg Se/kg as Se-enriched yeast (Angel Yeast) for 16 wk. Although mRNA abundance of the 13 selenoproteins in 10 tissues responded to dietary Se in 3 patterns, there was no common regulation for any given gene across all tissues or for any given tissue across all genes. Dietary Se affected (P < 0.05) 2, 3, 3, 5, 6, 7, 7, and 8 selenoprotein genes in muscle, hypothalamus, liver, kidney, heart, spleen, thyroid, and pituitary, respectively. Protein abundance of Gpx1, Sepp1, Selh, and Sels in 6 tissues was regulated (P < 0.05) by dietary Se concentrations in 3 ways. Compared with those fed 0.3 mg Se/kg, pigs fed 3.0 mg Se/kg became hyperinsulinemic (P < 0.05) and had lower (P < 0.05) tissue levels of serine/threonine protein kinase. In conclusion, dietary Se exerted no global regulation of gene transcripts or protein levels of individual selenoproteins across porcine tissues. Pigs may be a good model for studying mechanisms related to the potential prodiabetic risk of high-Se intake in humans. PMID:22739382

  11. Prolonged dietary selenium deficiency or excess does not globally affect selenoprotein gene expression and/or protein production in various tissues of pigs.

    PubMed

    Liu, Yan; Zhao, Hua; Zhang, Qiaoshan; Tang, Jiayong; Li, Ke; Xia, Xin-Jie; Wang, Kang-Ning; Li, Kui; Lei, Xin Gen

    2012-08-01

    We previously determined the effects of dietary selenium (Se) deficiency or excess on mRNA abundance of 12 selenoprotein genes in pig tissues. In this study, we determined the effect of dietary Se on mRNA levels of the remaining porcine selenoprotein genes along with protein production of 4 selenoproteins (Gpx1, Sepp1, Selh, and Sels) and body glucose homeostasis. Weanling male pigs (n = 24) were fed a Se-deficient (<0.02 mg Se/kg), basal diet supplemented with 0, 0.3, or 3.0 mg Se/kg as Se-enriched yeast (Angel Yeast) for 16 wk. Although mRNA abundance of the 13 selenoproteins in 10 tissues responded to dietary Se in 3 patterns, there was no common regulation for any given gene across all tissues or for any given tissue across all genes. Dietary Se affected (P < 0.05) 2, 3, 3, 5, 6, 7, 7, and 8 selenoprotein genes in muscle, hypothalamus, liver, kidney, heart, spleen, thyroid, and pituitary, respectively. Protein abundance of Gpx1, Sepp1, Selh, and Sels in 6 tissues was regulated (P < 0.05) by dietary Se concentrations in 3 ways. Compared with those fed 0.3 mg Se/kg, pigs fed 3.0 mg Se/kg became hyperinsulinemic (P < 0.05) and had lower (P < 0.05) tissue levels of serine/threonine protein kinase. In conclusion, dietary Se exerted no global regulation of gene transcripts or protein levels of individual selenoproteins across porcine tissues. Pigs may be a good model for studying mechanisms related to the potential prodiabetic risk of high-Se intake in humans.

  12. Selenium in bovine spermatozoa.

    PubMed

    Niemi, S M; Kuzan, F B; Senger, P L

    1981-05-01

    This study investigated the association of selenium with ejaculated bovine spermatozoa. Over 75% of the radioactive spermatozoa. Over 75% of the radioactive selenium-75 was released after 30 min of incubation in 2 X 10(-3) dithiothreitol. Of the selenium-75 released by dithiothreitol, 85% was associated with spermatozoal protein. Protein containing selenium-75 was found predominantly in a single band after polyacrylamide gel electrophoresis. Molecular weight was approximately 21,500 daltons.

  13. Bioavailability of zinc oxide added to corn tortilla is similar to that of zinc sulfate and is not affected by simultaneous addition of iron

    PubMed Central

    Rosado, Jorge L.; Díaz, Margarita; Muñoz, Elsa; Westcott, Jamie L.; González, Karla E.; Krebs, Nancy F.; Caamaño, María C.; Hambidge, Michael

    2013-01-01

    Background Corn tortilla is the staple food of Mexico and its fortification with zinc, iron, and other micronutrients is intended to reduce micronutrient deficiencies. However, no studies have been performed to determine the relative amount of zinc absorbed from the fortified product and whether zinc absorption is affected by the simultaneous addition of iron. Objective To compare zinc absorption from corn tortilla fortified with zinc oxide versus zinc sulfate and to determine the effect of simultaneous addition of two doses of iron on zinc bioavailability. Methods A randomized, double-blind, crossover design was carried out in two phases. In the first phase, 10 adult women received corn tortillas with either 20 mg/kg of zinc oxide added, 20 mg/kg of zinc sulfate added, or no zinc added. In the second phase, 10 adult women received corn tortilla with 20 mg/kg of zinc oxide added and either with no iron added or with iron added at one of two different levels. Zinc absorption was measured by the stable isotope method. Results The mean (± SEM) fractional zinc absorption from unfortified tortilla, tortilla fortified with zinc oxide, and tortilla fortified with zinc sulfate did not differ among treatments: 0.35 ± 0.07, 0.36 ± 0.05, and 0.37 ± 0.07, respectively. The three treatment groups with 0, 30, and 60 mg/kg of added iron had similar fractional zinc absorption (0.32 ± 0.04, 0.33 ± 0.02, and 0.32 ± 0.05, respectively) and similar amounts of zinc absorbed (4.8 ± 0.7, 4.5 ± 0.3, and 4.8 ± 0.7 mg/day, respectively). Conclusions Since zinc oxide is more stable and less expensive and was absorbed equally as well as zinc sulfate, we suggest its use for corn tortilla fortification. Simultaneous addition of zinc and iron to corn tortilla does not modify zinc bioavailability at iron doses of 30 and 60 mg/kg of corn flour. PMID:23424892

  14. Bioavailability of zinc oxide added to corn tortilla is similar to that of zinc sulfate and is not affected by simultaneous addition of iron.

    PubMed

    Rosado, Jorge L; Díaz, Margarita; Muñoz, Elsa; Westcott, Jamie L; González, Karla E; Krebs, Nancy F; Caamaño, María C; Hambidge, Michael

    2012-12-01

    Corn tortilla is the staple food of Mexico and its fortification with zinc, iron, and other micronutrients is intended to reduce micronutrient deficiencies. However, no studies have been performed to determine the relative amount of zinc absorbed from the fortified product and whether zinc absorption is affected by the simultaneous addition of iron. To compare zinc absorption from corn tortilla fortified with zinc oxide versus zinc sulfate and to determine the effect of simultaneous addition of two doses of iron on zinc bioavailability. A randomized, double-blind, crossover design was carried out in two phases. In the first phase, 10 adult women received corn tortillas with either 20 mg/kg of zinc oxide added, 20 mg/kg of zinc sulfate added, or no zinc added. In the second phase, 10 adult women received corn tortilla with 20 mg/kg of zinc oxide added and either with no iron added or with iron added at one of two different levels. Zinc absorption was measured by the stable isotope method. The mean (+/- SEM) fractional zinc absorption from unfortified tortilla, tortilla fortified with zinc oxide, and tortilla fortified with zinc sulfate did not differ among treatments: 0.35 +/- 0.07, 0.36 +/- 0.05, and 0.37 +/- 0.07, respectively. The three treatment groups with 0, 30, and 60 mg/kg of added iron had similar fractional zinc absorption (0.32 +/- 0.04, 0.33 +/- 0.02, and 0.32 +/- 0.05, respectively) and similar amounts of zinc absorbed (4.8 +/- 0.7, 4.5 +/- 0.3, and 4.8 +/- 0.7 mg/day, respectively). Since zinc oxide is more stable and less expensive and was absorbed equally as well as zinc sulfate, we suggest its use for corn tortilla fortification. Simultaneous addition of zinc and iron to corn tortilla does not modify zinc bioavailability at iron doses of 30 and 60 mg/kg of corn flour.

  15. Thyroid hormones regulate selenoprotein expression and selenium status in mice.

    PubMed

    Mittag, Jens; Behrends, Thomas; Hoefig, Carolin S; Vennström, Björn; Schomburg, Lutz

    2010-09-22

    Impaired expression of selenium-containing proteins leads to perturbed thyroid hormone (TH) levels, indicating the central importance of selenium for TH homeostasis. Moreover, critically ill patients with declining serum selenium develop a syndrome of low circulating TH and a central downregulation of the hypothalamus-pituitary-thyroid axis. This prompted us to test the reciprocal effect, i.e., if TH status would also regulate selenoprotein expression and selenium levels. To investigate the TH dependency of selenium metabolism, we analyzed mice expressing a mutant TH receptor α1 (TRα1+m) that confers a receptor-mediated hypothyroidism. Serum selenium was reduced in these animals, which was a direct consequence of the mutant TRα1 and not related to their metabolic alterations. Accordingly, hyperthyroidism, genetically caused by the inactivation of TRβ or by oral TH treatment of adult mice, increased serum selenium levels in TRα1+m and controls, thus demonstrating a novel and specific role for TRα1 in selenium metabolism. Furthermore, TH affected the mRNA levels for several enzymes involved in selenoprotein biosynthesis as well as serum selenoprotein P concentrations and the expression of other antioxidative selenoproteins. Taken together, our results show that TH positively affects the serum selenium status and regulates the expression of several selenoproteins. This demonstrates that selenium and TH metabolism are interconnected through a feed-forward regulation, which can in part explain the rapid parallel downregulation of both systems in critical illness.

  16. Nutritional plane and selenium supply during gestation affect yield and nutrient composition of colostrum and milk in primiparous ewes.

    PubMed

    Meyer, A M; Reed, J J; Neville, T L; Thorson, J F; Maddock-Carlin, K R; Taylor, J B; Reynolds, L P; Redmer, D A; Luther, J S; Hammer, C J; Vonnahme, K A; Caton, J S

    2011-05-01

    cell count and total somatic cells were greater (P ≤ 0.05) in milk from CON than RES. A cubic effect of day (P ≥ 0.01) was observed for milk yield (g and mL). Butterfat, solids-not-fat, lactose, milk urea N, and Se concentration responded quadratically (P ≤ 0.01) to day. Protein (%), total butterfat, and total Se, and somatic cells (cells/mL and cells/d) decreased linearly (P < 0.01) with day. Results indicate that gestational nutrition affects colostrum and milk yield and nutrient content, even when lactational nutrient requirements are met.

  17. Selenium cytotoxicity in cancer.

    PubMed

    Wallenberg, Marita; Misra, Sougat; Björnstedt, Mikael

    2014-05-01

    Selenium is an essential trace element with growth-modulating properties. Decades of research clearly demonstrate that selenium compounds inhibit the growth of malignant cells in diverse experimental model systems. However, the growth-modulating and cytotoxic mechanisms are diverse and far from clear. Lately, a remarkable tumour selective cytotoxicity of selenium compounds has been shown, indicating the potential of selenium in the treatment of cancer. Of particular interest are the redox-active selenium compounds exhibiting cytotoxic potential to tumour cells. These selenium compounds elicit complex patterns of pharmacodynamics and pharmacokinetics, leading to cell death pathways that differ among compounds. Modern oncology often focuses on targeted ligand-based therapeutic strategies that are specific to their molecular targets. These drugs are initially efficient, but the tumour cells often rapidly develop resistance against these drugs. In contrast, certain redox-active selenium compounds induce complex cascades of pro-death signalling at pharmacological concentrations with superior tumour specificity. The target molecules are often the ones that are important for the survival of cancer cells and often implicated in drug resistance. Therefore, the chemotherapeutic applications of selenium offer great possibilities of multi-target attacks on tumour cells. This MiniReview focuses on the tumour-specific cytotoxic effects of selenium, with special emphasis on cascades of cellular events induced by the major groups of pharmacologically active selenium compounds. Furthermore, the great pharmacological potential of selenium in the treatment of resistant cancers is discussed.

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

    PubMed

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

    2011-06-15

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

  19. Deletion of apolipoprotein E receptor-2 in mice lowers brain selenium and causes severe neurological dysfunction and death when a low-selenium diet is fed.

    PubMed

    Burk, Raymond F; Hill, Kristina E; Olson, Gary E; Weeber, Edwin J; Motley, Amy K; Winfrey, Virginia P; Austin, Lori M

    2007-06-06

    Selenoprotein P (Sepp1) is a plasma and extracellular protein that is rich in selenium. Deletion of Sepp1 results in sharp decreases of selenium levels in the brain and testis with dysfunction of those organs. Deletion of Sepp1 also causes increased urinary selenium excretion, leading to moderate depletion of whole-body selenium. The lipoprotein receptor apolipoprotein E receptor-2 (apoER2) binds Sepp1 and facilitates its uptake by Sertoli cells, thus providing selenium for spermatogenesis. Experiments were performed to assess the effect of apoER2 on the concentration and function of selenium in the brain and on whole-body selenium. ApoER2-/- and apoER2+/+ male mice were fed a semipurified diet with selenite added as the source of selenium. ApoER2-/- mice had depressed brain and testis selenium, but normal levels in liver, kidney, muscle, and the whole body. Feeding a selenium-deficient diet to apoER2-/- mice led to neurological dysfunction and death, with some of the characteristics exhibited by Sepp1-/- mice fed the same diet. Thus, although it does not affect whole-body selenium, apoER2 is necessary for maintenance of brain selenium and for prevention of neurological dysfunction and death under conditions of selenium deficiency, suggesting an interaction of apoER2 with Sepp1 in the brain.

  20. Biomarkers of carotenoid bioavailability.

    PubMed

    Granado-Lorencio, F; Blanco-Navarro, I; Pérez-Sacristán, B; Hernández-Álvarez, E

    2017-09-01

    The use of biomarkers constitutes an essential tool to assess the bioavailability of carotenoids in humans. The present article aims to review several methodological, host-related and modulating factors relevant on assessing and interpreting carotenoid bioavailability. Markers for carotenoid bioavailability can be broadly divided into direct, biochemical or "analytical" markers and indirect, physiological or "functional" indicators. Analytical markers usually refer to biochemical indicators of intake and/or status (short and long term exposure) while functional measures may be interpreted in terms of cumulative exposure, biological effect (bioactivity) or modification of risk factors. Both types of markers display advantages and limitations but, in general, a relationship exists among the type of marker, the biological specimen needed and the time required for a change. Humans may absorb a wide range of carotenes and xanthophylls and many of them may be found in serum and tissues. However, under physiological conditions, the several classes of dietary carotenoids may behave unequally leading to a different systemic profile and, moreover, they can be selectively accumulated at target tissues. In addition, some carotenoids may be chemically and enzymatically modified generating different oxidative metabolites and apocarotenoids. Quantitatively, the biological response upon carotenoid intervention (assessed by analytical and functional markers) is highly variable but the use of large doses and long-term protocols may lead to saturation effects and the loss of linearity in the response. Also, despite carotenoid exposition is considered to be safe, markers of overexposure include clinical signs (i.e. carotenodermia, corneal rings and retinopathy) and biochemical indicators (hypercarotenemia, xanthophyll esters). Overall, both host-related and methodological factors may influence analytical and functional markers to assess carotenoid bioavailability although the

  1. Amount of fat in the diet affects bioavailability of lutein esters but not of alpha-carotene, beta-carotene, and vitamin E in humans.

    PubMed

    Roodenburg, A J; Leenen, R; van het Hof, K H; Weststrate, J A; Tijburg, L B

    2000-05-01

    Fat-soluble vitamin E and carotenoids are regarded as being protective against chronic diseases. Little is known about the effect of dietary fat on the bioavailability of these compounds. The objective of this study was to assess the effect of the amount of dietary fat on plasma concentrations of vitamin E and carotenoids after supplementation with these compounds. During two 7-d periods, 4 groups of 14-15 volunteers received daily, with a low-fat hot meal, 1 of 4 different supplements: vitamin E (50 mg), alpha- plus beta-carotene (8 mg), lutein esters (8 mg lutein), or placebo. The supplements were provided in a low- or high-fat spread supplied in random sequence during either of the 2 experimental periods. As anticipated, plasma concentrations of vitamin E, alpha- and beta-carotene, and lutein were significantly higher in the supplemented groups than in the placebo group. The amount of dietary fat consumed with the hot meal (3 or 36 g) did not affect the increases in plasma concentrations of vitamin E (20% increase with the low-fat spread and 23% increase with the high-fat spread) or alpha- and beta-carotene (315% and 139% with the low-fat spread and 226% and 108% with the high-fat spread). The plasma lutein response was higher when lutein esters were consumed with the high-fat spread (207% increase) than with the low-fat spread (88% increase). Optimal uptake of vitamin E and alpha- and beta-carotene requires a limited amount of fat whereas the amount of fat required for optimal intestinal uptake of lutein esters is higher. 2000;71:-93.

  2. Assessing bioavailability levels of metals in effluent-affected rivers: effect of Fe(III) and chelating agents on the distribution of metal speciation.

    PubMed

    Han, Shuping; Naito, Wataru; Masunaga, Shigeki

    To assess the effects of Fe(III) and anthropogenic ligands on the bioavailability of Ni, Cu, Zn, and Pb, concentrations of bioavailable metals were measured by the DGT (diffusive gradients in thin films) method in some urban rivers, and were compared with concentrations calculated by a chemical equilibrium model (WHAM 7.0). Assuming that dissolved Fe(III) (<0.45 μm membrane filtered) was in equilibrium with colloidal iron oxide, the WHAM 7.0 model estimated that bioavailable concentrations of Ni, Cu, and Zn were slightly higher than the corresponding values estimated assuming that dissolved Fe(III) was absent. In contrast, lower levels of free Pb were predicted by the WHAM 7.0 model when dissolved Fe(III) was included. Estimates showed that most of the dissolved Pb was present as colloidal iron-Pb complex. Ethylene-diamine-tetra-acetic acid (EDTA) concentrations at sampling sites were predicted from the relationship between EDTA and the calculated bioavailable concentration of Zn. When both colloidal iron and predicted EDTA concentrations were included in the WHAM 7.0 calculations, dissolved metals showed a strong tendency to form EDTA complexes, in the order Ni > Cu > Zn > Pb. With the inclusion of EDTA, bioavailable concentrations of Ni, Cu, and Zn predicted by WHAM 7.0 were different from those predicted considering only humic substances and colloidal iron.

  3. Impaired reproduction of mallards fed an organic form of selenium

    USGS Publications Warehouse

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

    1989-01-01

    We fed mallards (Anas platyrhynchos) diets supplemented with 0-, 1-, 2-, 4-, 8-, or 16-ppm selenium in the form of selenomethionine. We fed another group of mallards a diet containing 16-ppm selenium as selenocystine. Females fed the control diet produced a mean of 8.1 ducklings that survived to 6 days of age, which was significantly greater than the 4.6 young produced by females fed 8-ppm selenium as selenomethionine and the zero surviving young of females fed 16-ppm selenium as selenomethionine. Selenocystine did not impair reproduction. Diets containing 8- and 16-ppm selenium as selenomethionine caused malformations in 6.8 and 67.9%, respectively, of unhatched eggs compared with 0.6% for controls. The most common malformations were of eyes, bill, legs, and feet. Selenium did not affect the onset or frequency of egg laying, egg size, shell thickness, fertility of eggs, or sex ratio of ducklings. Reduced survival and growth occurred in ducklings hatched from groups whose parents had received 8- or 16-ppm selenium as selenomethionine, even though all ducklings were fed a control diet. Concentrations of selenium in eggs and liver of adults could be predicted from dietary concentrations. We conclude that the dietary threshold of selenium as selenomethionine necessary to impair reproduction is between 4 and 8 ppm. It is difficult to identify 1 level of selenium in eggs that will be diagnostic of reproductive impairment in the field because different chemical forms of selenium appear to have different toxicities in eggs. However, when eggs from a wild population contain .gtoreq. 1-ppm selenium on a wet-weight basis, reproductive impairment may be possible and should be evaluated in that population. At 5-ppm selenium in eggs, reproductive impairment is much more likely to occur.

  4. Biomonitoring Equivalents for selenium.

    PubMed

    Hays, Sean M; Macey, Kristin; Nong, Andy; Aylward, Lesa L

    2014-10-01

    Selenium is an essential nutrient for human health with a narrow range between essentiality and toxicity. Selenium is incorporated into several proteins that perform important functions in the body. With insufficient selenium intake, the most notable effect is Keshan disease, an endemic cardiomyopathy in children. Conversely, excessive selenium intake can result in selenosis, manifested as brittle nails and hair and gastro-intestinal disorders. As such, guidance values have been established to protect against both insufficient and excessive selenium exposures. Dietary Reference Intakes (DRIs) have been established as standard reference values for nutritional adequacy in North America. To protect against selenosis resulting from exposure to excessive amounts of selenium, several government and non-governmental agencies have established a range of guidance values. Exposure to selenium is primarily through the diet, but monitoring selenium intake is difficult. Biomonitoring is a useful means of assessing and monitoring selenium status for both insufficient and excessive exposures. However, to be able to interpret selenium biomonitoring data, levels associated with both DRIs and toxicity guidance values are required. Biomonitoring Equivalents (BEs) were developed for selenium in whole blood, plasma and urine. The BEs associated with assuring adequate selenium intake (Estimated Average Requirements - EAR) are 100, 80 and 10μg/L in whole blood, plasma and urine, respectively. The BEs associated with protection against selenosis range from 400 to 480μg/L in whole blood, 180-230μg/L in plasma, and 90-110μg/L in urine. These BE values can be used by both regulatory agencies and public health officials to interpret selenium biomonitoring data in a health risk context.

  5. Selenium status in food grains of northern districts of India.

    PubMed

    Yadav, Sanjiv K; Singh, Ishwar; Sharma, Anita; Singh, Devender

    2008-09-01

    The selenium status in the food grains of the agricultural lands of northern parts of India was estimated by using the HG-AAS technique. The areas where lesser rains were received or less irrigation water was available in northern Indian states viz. Rajasthan and southern parts of the Haryana had higher selenium levels in food grains. Punjab, Himachal Pradesh and northern parts of the Haryana states had normal levels of selenium in their food grains, except for slightly lower selenium levels in a few areas that were affected by floods along the river Yamuna.

  6. Selenium status in soils of northern districts of India.

    PubMed

    Yadav, Sanjiv K; Singh, Ishwar; Singh, Devender; Han, Sang-Do

    2005-04-01

    The HG-AAS technique was used to estimate the soil selenium status of the agricultural lands of northern parts of India. The drier lands where lesser rains were received or where less irrigation water was available in Rajasthan and southern parts of the Haryana states had above normal soil selenium levels. These soils were also found to be alkaline. Punjab, Himachal Pradesh and northern parts of the Haryana states had normal levels of selenium in their soils, except with slightly lower selenium levels in a few areas that were affected by floods along the river Yamuna. The results were also confirmed using the ICP-OES technique.

  7. Heavy metals in soils from Baia Mare mining impacted area (Romania) and their bioavailability

    NASA Astrophysics Data System (ADS)

    Roba, Carmen; Baciu, Calin; Rosu, Cristina; Pistea, Ioana; Ozunu, Alexandru

    2015-04-01

    Keywords: heavy metals, soil contamination, bioavailability, Romania The fate of various metals, including chromium, nickel, copper, manganese, mercury, cadmium, and lead, and metalloids, like arsenic, antimony, and selenium, in the natural environment is of great concern, particularly in the vicinity of former mining sites, dumps, tailings piles, and impoundments, but also in urban areas and industrial centres. Most of the studies focused on the heavy metal pollution in mining areas present only the total amounts of metals in soils. The bioavailable concentration of metals in soil may be a better predictor for environmental impact of historical and current dispersion of metals. Assessment of the metal bioavailability and bioaccessibility is critical in understanding the possible effects on soil biota. The bioavailability of metals in soil and their retention in the solid phase of soil is affected by different parameters like pH, metal amount, cation-exchange capacity, content of organic matter, or soil mineralogy. The main objectives of the present study were to determine the total fraction and the bioavailable fraction of Cu, Cd, Pb and Zn from soil in a well-known mining region in Romania, and to evaluate the influence of soil pH on the metal bioavailability in soil. The heavy metal contents and their bioavailability were monitored in a total of 50 soil samples, collected during June and July 2014 from private gardens of the inhabitants from Baia-Mare area. The main mining activities developed in the area consisted of non-ferrous sulphidic ores extraction and processing, aiming to obtain concentrates of lead, copper, zinc and precious metals. After 2006, the metallurgical industry has considerably reduced its activity by closing or diminishing its production capacity. The analysed soil samples proved to have high levels of Pb (50 - 830 mg/kg), Cu (40 - 600 mg/kg), Zn (100 - 700 mg/kg) and Cd (up to 10 mg/kg). The metal abundance in the total fraction is

  8. Hazard assessment of selenium to endangered razorback suckers (Xyrauchen texanus)

    USGS Publications Warehouse

    Hamilton, S.J.; Holley, K.M.; Buhl, K.J.

    2002-01-01

    A hazard assessment was conducted based on information derived from two reproduction studies conducted with endangered razorback suckers (Xyrauchen texanus) at three sites near Grand Junction, CO, USA. Selenium contamination of the upper and lower Colorado River basin has been documented in water, sediment, and biota in studies by US Department of the Interior agencies and academia. Concern has been raised that this selenium contamination may be adversely affecting endangered fish in the upper Colorado River basin. The reproduction studies with razorback suckers revealed that adults readily accumulated selenium in various tissues including eggs, and that 4.6 μg/g of selenium in food organisms caused increased mortality of larvae. The selenium hazard assessment protocol resulted in a moderate hazard at the Horsethief site and high hazards at the Adobe Creek and North Pond sites. The selenium hazard assessment was considered conservative because an on-site toxicity test with razorback sucker larvae using 4.6 μg/g selenium in zooplankton caused nearly complete mortality, in spite of the moderate hazard at Horsethief. Using the margin of uncertainty ratio also suggested a high hazard for effects on razorback suckers from selenium exposure. Both assessment approaches suggested that selenium in the upper Colorado River basin adversely affects the reproductive success of razorback suckers.

  9. Carbohydrate bioavailability.

    PubMed

    Englyst, Klaus N; Englyst, Hans N

    2005-07-01

    There is consensus that carbohydrate foods, in the form of fruit, vegetables and whole-grain products, are beneficial to health. However, there are strong indications that highly processed, fibre-depleted, and consequently rapidly digestible, energy-dense carbohydrate food products can lead to over-consumption and obesity-related diseases. Greater attention needs to be given to carbohydrate bioavailability, which is determined by the chemical identity and physical form of food. The objective of the present concept article is to provide a rational basis for the nutritional characterisation of dietary carbohydrates. Based on the properties of carbohydrate foods identified to be of specific relevance to health, we propose a classification and measurement scheme that divides dietary carbohydrates into glycaemic carbohydrates (digested and absorbed in the small intestine) and non-glycaemic carbohydrates (enter the large intestine). The glycaemic carbohydrates are characterised by sugar type, and by the likely rate of digestion described by in vitro measurements for rapidly available glucose and slowly available glucose. The main type of non-glycaemic carbohydrates is the plant cell-wall NSP, which is a marker of the natural fibre-rich diet recognised as beneficial to health. Other non-glycaemic carbohydrates include resistant starch and the resistant short-chain carbohydrates (non-digestible oligosaccharides), which should be measured and researched in their own right. The proposed classification and measurement scheme is complementary to the dietary fibre and glycaemic index concepts in the promotion of healthy diets with low energy density required for combating obesity-related diseases.

  10. Relative Bioavailability and Bioaccessability and Speciation of ...

    EPA Pesticide Factsheets

    Background: Assessment of soil arsenic (As) bioavailability may profoundly affect the extent of remediation required at contaminated sites by improving human exposure estimates. Because small adjustments in soil As bioavailability estimates can significantly alter risk assessments and remediation goals, convenient, rapid, reliable, and inexpensive tools are needed to determine soil As bioavailability. Objectives: We evaluated inexpensive methods for assessing As bioavailability in soil as a means to improve human exposure estimates and potentially reduce remediation costs. Methods: Nine soils from residential sites affected by mining or smelting activity and two National Institute of Standards and Technology standard reference materials were evaluated for As bioavailability, bioaccessibility, and speciation. Arsenic bioavailability was determined using an in vivo mouse model, and As bioaccessibility was determined using the Solubility/Bioavailability Research Consortium in vitro assay. Arsenic speciation in soil and selected soil physicochemical properties were also evaluated to determine whether these parameters could be used as predictors of As bio¬availability and bioaccessibility. Results: In the mouse assay, we compared bioavailabilities of As in soils with that for sodium arsenate. Relative bioavailabilities (RBAs) of soil As ranged from 11% to 53% (mean, 33%). In vitro soil As bioaccessibility values were strongly correlated with soil As RBAs (R

  11. Selenium biogeochemistry in reservoirs

    SciTech Connect

    Cutter, G.A. . Dept. of Oceanography)

    1991-05-01

    Three reservoirs (Belews and Hyco in North Carolina and Philpott in Virginia) were sampled over a three-year period by Old Dominion University. Two additional reservoirs (Martin and Murval in Texas) were sampled by Battelle Pacific Northwest Laboratory. Total dissolved selenium, selenite, selenate, Se({minus}II+0), and organic selenide were determined in water samples from the lakes, their primary water inputs, and their outflows. Selenium speciation was also determined in suspended particulate matter, sediments, and plankton. Concentrations of total dissolved selenium are highest in reservoirs associated with power plants, and within these systems selenite is the dominant form of dissolved selenium. In control reservoirs (Philpott and Murval), Se({minus}II+0) is the predominant form of dissolved selenium. Within the sediments, elemental selenium and organic selenides are the dominant forms of particulate selenium. These speciation patterns can be attributed to the primary sources of selenium to the reservoirs (runoff into the control reservoirs and effluents from fly ash ponds into the power plant reservoirs) and to the biogeochemical processing of selenium within the reservoirs. The concentration and speciation of selenium in freshwater depends on selenium source (runoff and effluents), internal cycling in the water column (biotic uptake and regeneration, redox transformations), and output via sedimentation and water outflow. A non-steady state, geochemical computer model was developed to simulate this cycle and to allow predictions of how selenium concentration and speciation would change with time when a variable (e.g., ash pond input) was altered. 29 refs., 51 figs., 4 tabs.

  12. Lentils (Lens culinaris L.) as a source of dietary selenium

    USDA-ARS?s Scientific Manuscript database

    The chapter discusses the nutritional value of lentils, with a focus on factors affecting lentils as a source of dietary selenium. It addresses the chemical nature of lentil-selenium, pointing out that more than 90% is present in organic compounds which are generally well absorbed by humans. The se...

  13. Production and Release of Selenomethionine and Related Organic Selenium Species by Microorganisms in Natural and Industrial Waters.

    PubMed

    LeBlanc, Kelly L; Wallschläger, Dirk

    2016-06-21

    Laboratory algal cultures exposed to selenate were shown to produce and release selenomethionine, selenomethionine oxide, and several other organic selenium metabolites. Released discrete organic selenium species accounted for 1.6-13.1% of the selenium remaining in the media after culture death, with 1.3-6.1% of the added selenate recovered as organic metabolites. Analysis of water from an industrially impacted river collected immediately after the death of massive annual algal blooms showed that no selenomethionine or selenomethionine oxide was present. However, other discrete organic selenium species, including a cyclic oxidation product of selenomethionine, were observed, indicating the previous presence of selenomethionine. Industrial biological treatment systems designed for remediation of selenium-contaminated waters were shown to increase both the concentration of organic selenium species in the effluent, relative to influent water, and the fraction of organic selenium to up to 8.7% of the total selenium in the effluent, from less than 1.1% in the influent. Production and emission of selenomethionine, selenomethionine oxide, and other discrete organic selenium species were observed. These findings are discussed in the context of potentially increased selenium bioavailability caused by microbial activity in aquatic environments and biological treatment systems, despite overall reductions in total selenium concentration.

  14. Effects of selenium on mallard duck reproduction and immune function

    SciTech Connect

    Whiteley, P.L.; Yuill, T.M.; Fairbrother, A.

    1989-11-01

    Selenium from irrigation drain water and coal-fired power stations is a significant environmental contaminant in some regions of the USA. The objectives were to examine whether selenium-exposed waterfowl had altered immune function, disease resistance, or reproduction. Pairs of adult mallards were exposed for 95-99 days on streams with sodium selenite-treated water at 10 and 30 ppb, or on untreated streams. Selenium biomagnified through the food chain to the ducks. Disease resistance was decreased in ducklings hatched on the streams and challenged with duck hepatitis virus 1 (DHV1) when 15-days old. Liver selenium concentrations for these ducklings on the 10 and 30 ppb streams was 3.6 and 7.6 ppm dry weight, respectively. Mortality of ducklings purchased when 7-days old, exposed to selenium for 14 days, and challenged when 22-days old was not affected. However, their selenium exposure was lower (liver selenium 4.1 ppm dry weight for the 30 ppb stream). Five parameters of immune function were measured in adult ducks. Phagocytosis of killed Pasteurella multocida by blood heterophils and monocytes, and blood monocyte concentrations were higher in adult males following 84 days exposure to 30 ppb selenium. Their liver selenium concentrations were 11.1 ppm dry weight after 95-99 days exposure.

  15. Selenium and thyroid function in infants, children and adolescents.

    PubMed

    Chanoine, Jean-Pierre

    2003-01-01

    Selenium is an integral component of the enzymes glutathione peroxidase (GPx) and iodothyronine deiodinases. Although selenium nutrition could conceivably affect thyroid function in infants, children and adolescents, available data suggest that the effect of selenium deficiency on thyroid function is relatively modest. In patients with isolated selenium deficiency (such as patients with phenylketonuria receiving a low-protein diet), peripheral thyroid hormone metabolism is impaired but there are no changes in thyrotropin (TSH) or clinical signs of hypothyroidism, suggesting that these patients are euthyroid. Selenium supplementation may be advisable to optimize tissue GPx activity and prevent potential oxidative stress damage. In areas where combined selenium and iodine deficiencies are present (such as endemic goiter areas in Central Africa), selenium deficiency may be responsible for the destruction of the thyroid gland in myxoedematous cretins but may also play a protective role by mitigating fetal hypothyroidism. In these areas, selenium supplementation should only be advocated at the same time or after iodine supplementation. In patients with absent or decreased production of thyroid hormones and who rely solely on deiodination of exogenous L-thyroxine for generation of the active triiodothyronine (such as patients with congenital hypothyroidism), selenium supplementation may optimize thyroid hormone feedback at the pituitary level and decrease stimulation of the residual thyroid tissue.

  16. Selenium and the control of thyroid hormone metabolism.

    PubMed

    Köhrle, Josef

    2005-08-01

    Thyroid hormone synthesis, metabolism and action require adequate availability of the essential trace elements iodine and selenium, which affect homeostasis of thyroid hormone-dependent metabolic pathways. The three selenocysteine-containing iodothyronine deiodinases constitute a novel gene family. Selenium is retained and deiodinase expression is maintained at almost normal levels in the thyroid gland, the brain and several other endocrine tissues during selenium deficiency, thus guaranteeing adequate local and systemic levels of the active thyroid hormone T(3). Due to their low tissue concentrations and their mRNA SECIS elements deiodinases rank high in the cellular and tissue-specific hierarchy of selenium distribution among various selenoproteins. While systemic selenium status and expression of abundant selenoproteins (glutathione peroxidase or selenoprotein P) is already impaired in patients with cancer, disturbed gastrointestinal resorption, unbalanced nutrition or patients requiring intensive care treatment, selenium-dependent deiodinase function might still be adequate. However, disease-associated alterations in proinflammatory cytokines, growth factors, hormones and pharmaceuticals modulate deiodinase isoenzyme expression independent from altered selenium status and might thus pretend causal relationships between systemic selenium status and altered thyroid hormone metabolism. Limited or inadequate supply of both trace elements, iodine and selenium, leads to complex rearrangements of thyroid hormone metabolism enabling adaptation to unfavorable conditions.

  17. Role of oceans as biogenic sources of selenium

    NASA Astrophysics Data System (ADS)

    Amouroux, David; Liss, Peter S.; Tessier, Emmanuel; Hamren-Larsson, Marie; Donard, Olivier F. X.

    2001-07-01

    The pathways leading to the volatilisation and atmospheric transfer of selenium from oceanic environments are poorly understood. They may however affect the global distribution of selenium and its impact on marine and terrestrial ecosystems. In this paper we describe the results of experiments which provide a reasonable estimate of the global selenium budget. Gaseous selenium compounds were determined in the North Atlantic Ocean during a Spring bloom of phytoplankton species which are known to be a large source of atmospheric sulphur. The results demonstrate that significant concentrations of gaseous selenium species occur in surface ocean waters, and their production is closely linked to the gaseous sulphur species turnover. Selective uptake and biotransformation of dissolved selenium in seawater by phytoplankton is a major pathway for the production of gaseous selenium compounds in marine environments and their emission to the atmosphere. It is therefore suggested that such a major selenium source supplies the terrestrial environment with selenium that can be used as an essential nutrient for animal and human life.

  18. Swedish views on selenium.

    PubMed

    Bruce, A

    1986-01-01

    For a long time selenium was known only for its toxic characteristics. During the last few decades selenium deficiency has been recognized as an important agricultural problem in Sweden. On average, grains and pastures only contain one tenth of the amount of selenium considered necessary to avoid symptoms of deficiency. However, the incidence of muscle degeneration among the animals has been low, probably due to imported animal feed. Since 1980 selenium has been added to animal feed, but only minor changes in the selenium content of Swedish food stuffs have been recorded. Some studies have shown that the average Swedish dietary intake of selenium is 10-70 micrograms/day. The lowest levels were found in vegan diets, based on locally-grown products. Swedish studies have found depressed glutathione peroxidase (GSH-Px) levels in patients with various skin disorders, including acne; myotonic dystrophy and rheumatic arthritis. Clinical trials with selenium supplementation have given positive results in some of these disorders as well as in some patients with disabling muscular and joint pains. Today there is a large sale of selenium tablets sometimes with additional vitamin E. The marketing of these tablets, however, is often based on unsubstantiated claims.

  19. Selenium species bioaccessibility in enriched radish (Raphanus sativus): a potential dietary source of selenium.

    PubMed

    Pedrero, Zoyne; Madrid, Yolanda; Cámara, Carmen

    2006-03-22

    An in vitro gastrointestinal method was employed to predict the potential bioavailability of selenium and its species from radish, belonging to the Brassicaceae family, grown in hydroponics media in the presence of inorganic selenium, such as Na2SeO3 and Na2SeO4. A low transformation of Se into organic forms was observed in radish plants grown in Se(VI)-enriched culture media. On the contrary, in those plants exposed to selenite, >95% of the total selenium was found as selenocystine (SeCys2), selenomethionine (SeMet), and Se-methylselenocysteine (SeMetSeCys). The concentrations of these species in fresh samples remained almost unaltered after a simulated gastrointestinal digestion. Therefore, a high selenium content of Se-methylselenocysteine (65%), previously reported as a cancer chemopreventive species, remained in the potentially bioabsorbable fraction. As these plants usually undergo a short development cycle, these results suggest that radish enriched in selenite could be a good choice as an organoselenium supplement for the human diet and animal feed.

  20. Translational Redefinition of UGA Codons Is Regulated by Selenium Availability*

    PubMed Central

    Howard, Michael T.; Carlson, Bradley A.; Anderson, Christine B.; Hatfield, Dolph L.

    2013-01-01

    Incorporation of selenium into ∼25 mammalian selenoproteins occurs by translational recoding whereby in-frame UGA codons are redefined to encode the selenium containing amino acid, selenocysteine (Sec). Here we applied ribosome profiling to examine the effect of dietary selenium levels on the translational mechanisms controlling selenoprotein synthesis in mouse liver. Dietary selenium levels were shown to control gene-specific selenoprotein expression primarily at the translation level by differential regulation of UGA redefinition and Sec incorporation efficiency, although effects on translation initiation and mRNA abundance were also observed. Direct evidence is presented that increasing dietary selenium causes a vast increase in ribosome density downstream of UGA-Sec codons for a subset of selenoprotein mRNAs and that the selenium-dependent effects on Sec incorporation efficiency are mediated in part by the degree of Sec-tRNA[Ser]Sec Um34 methylation. Furthermore, we find evidence for translation in the 5′-UTRs for a subset of selenoproteins and for ribosome pausing near the UGA-Sec codon in those mRNAs encoding the selenoproteins most affected by selenium availability. These data illustrate how dietary levels of the trace element selenium can alter the readout of the genetic code to affect the expression of an entire class of proteins. PMID:23696641

  1. Gender-specific distribution of selenium to serum selenoproteins: associations with total selenium levels, age, smoking, body mass index, and physical activity.

    PubMed

    Letsiou, S; Nomikos, T; Panagiotakos, D B; Pergantis, S A; Fragopoulou, E; Pitsavos, C; Stefanadis, C; Antonopoulou, S

    2014-01-01

    The epidemiology of selenium (Se) is mainly based on the determination of total serum selenium levels (TSe) which by many aspects is an inadequate marker of Se status. In this study we applied a recently developed LC-ICP-MS method, for the determination of the selenium content of the three main serum selenium-containing proteins, in a subcohort of the ATTICA study. This enables us to investigate whether the selenium distribution to selenoproteins may correlate with demographic (age, gender) and lifestyle variables (smoking, physical activity) that are crucial for the development of chronic diseases. A sub-sample from the ATTICA Study, consisted of 236 males (40 ± 11 years) and 163 females (38 ± 12 years), was selected. The selenium content of glutathione peroxidase (GPx-3), selenoprotein P (SelP) and selenoalbumin (SeAlb) was determined in serum by LC-ICP/MS method. We found that 26% of TSe is found in GPx-3, 61% in SelP and 13% in SeAlb. We have assessed the different ratios of selenoproteins' selenium content (Se-GPX-3/Se-SelP, Se-GPX-3/Se-SeAlb, Se-SelP/Se-SeAlb), showing that people with similar TSe may have different distribution of this selenium to selenoproteins. Total selenium levels and gender are the variables that mostly affect selenium distribution to selenoproteins while age, smoking, physical activity and BMI do not significantly influence selenium distribution. In conclusion, the simultaneous determination of the selenium content of serum selenium-containing selenoproteins is necessary for a thorough estimation of selenium status. The ratio of the Se content between selenoproteins may be proven a novel, valid marker of selenium status. © 2014 International Union of Biochemistry and Molecular Biology.

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

    PubMed Central

    Burger, Joanna; Jeitner, Christian; Donio, Mark; Pittfield, Taryn; Gochfeld, Michael

    2015-01-01

    A number of contaminants affect fish health, including mercury and selenium, and the selenium: mercury molar ratio. Recently the protective effects of selenium on methylmercury toxicity have been publicized, particularly for consumption of saltwater fish. Yet the relative ameliorating effects of selenium on toxicity within fish have not been examined, nor has the molar ratio in different tissues, (i.e. brain). We examined mercury and selenium levels in brain, kidney, liver, red and white muscle, and skin and scales in bluefish (Pomatomus saltatrix) from New Jersey to determine whether there were toxic levels of either metal, and we computed the selenium: mercury molar ratios by tissues. Total mercury averaged 0.32 ± 0.02 ppm wet weight in edible muscle and 0.09 ± 0.01 ppm in brain. Selenium concentration averaged 0.37 ± 0.03 in muscle and 0.36 ± 0.03 ppm in brain. There were significant differences in levels of mercury, selenium, and selenium: mercury molar ratios, among tissues. Mercury and selenium levels were correlated in kidney and skin/scales. Mercury levels were highest in kidney, intermediate in muscle and liver, and lowest in brain and skin/scales; selenium levels were also highest in kidney, intermediate in liver, and were an order of magnitude lower in the white muscle and brain. Mercury levels in muscle, kidney and skin/scales were positively correlated with fish size (length). Selenium levels in muscle, kidney and liver were positively correlated with fish length, but in brain; selenium levels were negatively correlated with fish length. The selenium: mercury molar ratio was negatively correlated with fish length for white muscle, liver, kidney, and brain, particularly for fish over 50 cm in length, suggesting that older fish experience less protective advantages of selenium against mercury toxicity than smaller fish, and that consumers of bluefish similarly receive less advantage from eating larger fish. PMID:23202378

  3. Selenium for preventing cancer

    PubMed Central

    Dennert, Gabriele; Zwahlen, Marcel; Brinkman, Maree; Vinceti, Marco; Zeegers, Maurice P A; Horneber, Markus

    2013-01-01

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

  4. [Bioavailability and factors influencing its rate].

    PubMed

    Vraníková, Barbora; Gajdziok, Jan

    2015-01-01

    Bioavailability can be defined as the rate and range of active ingredient absorption, when it becomes available in the systemic circulation or at the desired site of drug action, respectively. Drug bioavailability after oral administration is affected by anumber of different factors, including physicochemical properties of the drug, physiological aspects, the type of dosage form, food intake, biorhythms, and intra- and interindividual variability of the human population. This article is the first from the series dealing with the bioavailability and methods leading to its improvement. The aim of the present paper is to provide an overview of aspects influencing the rate of bioavailability after oral administration of the active ingredient. Subsequentarticles will provide detailed descriptions of methods used for dug bioavailability improvement, which are here only summarized.

  5. Animal versus human oral drug bioavailability: do they correlate?

    PubMed

    Musther, Helen; Olivares-Morales, Andrés; Hatley, Oliver J D; Liu, Bo; Rostami Hodjegan, Amin

    2014-06-16

    Oral bioavailability is a key consideration in development of drug products, and the use of preclinical species in predicting bioavailability in human has long been debated. In order to clarify whether any correlation between human and animal bioavailability exist, an extensive analysis of the published literature data was conducted. Due to the complex nature of bioavailability calculations inclusion criteria were applied to ensure integrity of the data. A database of 184 compounds was assembled. Linear regression for the reported compounds indicated no strong or predictive correlations to human data for all species, individually and combined. The lack of correlation in this extended dataset highlights that animal bioavailability is not quantitatively predictive of bioavailability in human. Although qualitative (high/low bioavailability) indications might be possible, models taking into account species-specific factors that may affect bioavailability are recommended for developing quantitative prediction.

  6. Selenium levels in neoplastic breast lesions.

    PubMed

    Alatise, O I; Babalola, O O; Omoniyi-Esan, G O; Lawal, O O; Adesunkanmi, A R; Agbakwuru, E A

    2013-06-01

    The aim of this prospective case controlled study was to evaluate the tissue levels of selenium in patients with cases of fibroadenoma, cancer of the breast and in the controls in order to relate them to the occurrence of breast diseases. Consecutive consenting patients who had histologically confirmed breast cancer and fibroadenoma attending the General surgical outpatients departments of Obafemi Awolowo University Teaching Hospital Complex, Ile-Ife, were recruited for the study. One gram of core disease breast tissues was taken for Selenium level estimation. There were 127 female subjects;. 95 (74.8%) cases of fibroadenoma and 32 (25.2%) of breast cancer. While breast cancer was common on the left, fibroadenoma was more common on the right breast (? = 8.994; p=0.011). The median tissue level of selenium in patients with fibroadenoma was 0.0272 mg/g with a range of 0.0124 to 0.0576 mg/g and that of the cancer patients was 0.0178 mg/g with a range 0.0072 to 0.0436 mg/g. These were statistically significantly different ( p=0.001). Factors affecting tissue selenium level include age (p<0.001), overall stage of breast cancer (p<0.001), maximum length of breast mass (p=0.023), previous delivery (p=0.004), age at last confinement (p=0.007), parity (p<0.001), oestrogen receptor (ER) status (p<0.001) and progesterone receptor (PR) status (p=0.021). Tissue selenium was lower in breast cancer than in fibroadenoma; Tissue selenium inhibits carcinogenesis; low tissue level of selenium therefore may be a factor in the development of breast cancer.

  7. Bioavailability of Promethazine during Spaceflight

    NASA Technical Reports Server (NTRS)

    Boyd, Jason L.; Wang, Zuwei; Putcha, Lakshmi

    2009-01-01

    Promethazine (PMZ) is the choice anti-motion sickness medication for treating space motion sickness (SMS) during flight. The side effects associated with PMZ include dizziness, drowsiness, sedation, and impaired psychomotor performance which could impact crew performance and mission operations. Early anecdotal reports from crewmembers indicate that these central nervous system side effects of PMZ are absent or greatly attenuated in microgravity, potentially due to changes in pharmacokinetics (PK) and pharmacodynamics in microgravity. These changes could also affect the therapeutic effectiveness of drugs in general and PMZ, in particular. In this investigation, we examined bioavailability and associated pharmacokinetics of PMZ in astronauts during and after space flight. Methods. Nine astronauts received, per their preference, PMZ (25 or 50 mg as intramuscular injection, oral tablet, or rectal suppository) on flight day one for the treatment of SMS and subsequently collected saliva samples and completed sleepiness scores for 72 h post dose. Thirty days after the astronauts returned to Earth, they repeated the protocol. Bioavailability and PK parameters were calculated and compared between flight and ground. Results. Maximum concentration (Cmax) was lower and time to reach Cmax (tmax) was longer in flight than on the ground. Area under the curve (AUC), a measure of bioavailability, was lower and biological half-life (t1/2) was longer in flight than on the ground. Conclusion. Results indicate that bioavailability of PMZ is reduced during spaceflight. Number of samples, sampling method, and sampling schedule significantly affected PK parameter estimates.

  8. Bioavailability of Promethazine during Spaceflight

    NASA Technical Reports Server (NTRS)

    Boyd, Jason L.; Wang, Zuwei; Putcha, Lakshmi

    2009-01-01

    Promethazine (PMZ) is the choice anti-motion sickness medication for treating space motion sickness (SMS) during flight. The side effects associated with PMZ include dizziness, drowsiness, sedation, and impaired psychomotor performance which could impact crew performance and mission operations. Early anecdotal reports from crewmembers indicate that these central nervous system side effects of PMZ are absent or greatly attenuated in microgravity, potentially due to changes in pharmacokinetics (PK) and pharmacodynamics in microgravity. These changes could also affect the therapeutic effectiveness of drugs in general and PMZ, in particular. In this investigation, we examined bioavailability and associated pharmacokinetics of PMZ in astronauts during and after space flight. Methods. Nine astronauts received, per their preference, PMZ (25 or 50 mg as intramuscular injection, oral tablet, or rectal suppository) on flight day one for the treatment of SMS and subsequently collected saliva samples and completed sleepiness scores for 72 h post dose. Thirty days after the astronauts returned to Earth, they repeated the protocol. Bioavailability and PK parameters were calculated and compared between flight and ground. Results. Maximum concentration (Cmax) was lower and time to reach Cmax (tmax) was longer in flight than on the ground. Area under the curve (AUC), a measure of bioavailability, was lower and biological half-life (t1/2) was longer in flight than on the ground. Conclusion. Results indicate that bioavailability of PMZ is reduced during spaceflight. Number of samples, sampling method, and sampling schedule significantly affected PK parameter estimates.

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

    PubMed

    Andrahennadi, Ruwandi; Wayland, Mark; Pickering, Ingrid J

    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.

  10. 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.

  11. 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.

  12. Mineral Commodity Profiles: Selenium

    USGS Publications Warehouse

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

    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.

  13. Selenium, iodine, and the relation with Kashin-Beck disease.

    PubMed

    Yao, Yunfeng; Pei, Fuxing; Kang, Pengde

    2011-01-01

    The etiology and pathogenesis of Kashin-Beck disease (KBD) remain uncertain at present. A deficiency of selenium and iodine is considered common in KBD-affected areas. Supplying selenium and iodine for the prevention of KBD has been performed in the past few decades in affected areas in China. Supplying selenium and/or iodine has produced positive http://www.iciba.com/different/effects in most KBD-affected areas, but there are some affected areas where the effects have been unclear and supplementation with selenium and/or iodine has not eliminated this disease. From animal and vitro experiments, we explore whether a deficiency of selenium and/or iodine may be the environmental factor causing KBD. KBD may have multiple etiologies. The role of selenium and iodine in KBD mainly involves antioxidation and maintenance of thyroid function according to the present review. Other important roles of selenium and iodine in KBD and a certain etiology of this disease need further study. Copyright © 2011 Elsevier Inc. All rights reserved.

  14. Selenium and immune responses

    SciTech Connect

    Kiremidjian-Schumacher, L.; Stotzky, G.

    1987-04-01

    Selenium (Se) affects all components of the immune system, i.e., the development and expression of nonspecific, humoral, and cell-mediated responses. In general, a deficiency in Se appears to result in immunosuppression, whereas supplementation with low doses of Se appears to result in augmentation and/or restoration of immunologic functions. A deficiency of Se has been shown to inhibit (1) resistance to microbial and viral infections, (2) neutrophil function, (3) antibody production, (4) proliferation of T and B lymphocytes in response to mitogens, and (5) cytodestruction by T lymphocytes and NK cells. Supplementation with Se has been shown to stimulate (1) the function of neutrophils, (2) production of antibodies, (3) proliferation of T and B lymphocytes in response to mitogens, (4) production of lymphokines, (5) NK cell-mediated cytodestruction, (6) delayed-type hypersensitivity reactions and allograft rejection, and (7) the ability of a host to reject transplanted malignant tumors. The mechanism(s) whereby Se affects the immune system is speculative. The effects of Se on the function of glutathione peroxidase and on the cellular levels of reduced glutathione and H/sub 2/Se, as well as the ability of Se to interact with cell membranes, probably represent only a few of many regulatory mechanisms. The manipulation of cellular levels of Se may be significant for the maintenance of general health and for the control of immunodeficiency disorders and the chemoprevention of cancer.

  15. 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.

  16. Transformation of heavy metal fractions on soil urease and nitrate reductase activities in copper and selenium co-contaminated soil.

    PubMed

    Hu, Bin; Liang, Dongli; Liu, Juanjuan; Lei, Lingming; Yu, Dasong

    2014-12-01

    This study aims to explore the effects of the distribution, transformation and bioavailability of different fractions of copper (Cu) and selenium (Se) in co-contaminated soils on soil enzymes, providing references for the phytoremediation of contaminated areas and agriculture environmental protection. Pot experiments and laboratory analysis were used to investigate the transformation and bioavailability of additional Cu and Se for pakchoi (Brassica chinensis) in co-contaminated soil. In the uncontaminated soil, Cu mainly existed in residual form, whereas Se was present in residual form and in elemental and organic-sulfide matter-bound form. In the contaminated soil, Cu mainly bound to Fe-Mn oxidates, whereas Se was in exchangeable and carbonates forms. After a month of pakchoi growth, Cu tended to transfer into organic matter-bound fractions, whereas Se tended to bound to Fe-Mn oxidates. The IR (reduced partition index) value of Cu decreased as the concentrations of Cu and Se gradually increased, whereas the IR value of Se decreased as the concentration of Se increased. The IR value before pakchoi planting and after it was harvested was not affected by the concentration of exogenous Cu. Soil urease and nitrate reductase activities were inhibited by Cu and Se pollution either individually or combined in different degrees, following the order nitrate reductase>urease. The significant correlation between the IR value and soil enzyme activities suggests that this value could be used to evaluate the bioavailability of heavy metals in soil. Path analysis showed that the variations in exchangeable Cu and organic-sulfide matter-bound and elemental Se had direct effects on the activities of the two enzymes, suggesting their high bioavailability. Therefore, the IR value and the transformation of metals in soil could be used as indicators in evaluating the bioavailability of heavy metals. Copyright © 2014 Elsevier Inc. All rights reserved.

  17. Selecting Lentil Accessions for Global Selenium Biofortification

    USDA-ARS?s Scientific Manuscript database

    Biofortification of lentil (Lens culinaris Medikus.) has the potential to provide adequate daily selenium (Se) to human diets. The objectives of this study were to (1) determine how low dose Se fertilizer application at germination affects seedling biomass, antioxidant activity, and Se uptake of 26 ...

  18. The properties, functions, and use of selenium compounds in living organisms.

    PubMed

    Bodnar, Malgorzata; Konieczka, Piotr; Namiesnik, Jacek

    2012-01-01

    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.

  19. A high fat diet does not affect the iron bioavailability in Wistar rats fed with chia and increases gene expression of iron metabolism proteins.

    PubMed

    da Silva, Bárbara Pereira; Matyelka, Jéssika Camila da Silva; Moreira, Maria Eliza de Castro; Toledo, Renata Celi Lopes; Della Lucia, Ceres Mattos; Pinheiro-Sant'Ana, Helena Maria; Martino, Hércia Stampini Duarte

    2016-12-07

    This study evaluated the effect of chia on the iron bioavailability and gene expression of proteins involved in iron metabolism in animals fed with a high fat diet and a standard diet. Four experimental groups were tested (n = 8): standard diet + ferrous sulfate (SD + FS), standard diet + chia (SD + C), high fat diet + ferrous sulfate (HFD + FS), high fat diet + chia (HFD + C). The hemoglobin gain, hemoglobin regeneration efficiency, biological relative value of HRE, serum ferritin and transferrin, liver iron concentration and gene expression of proteins were evaluated. The SD + C group showed lower transferrin expression when compared to the control group. The control group showed serum transferrin concentration higher than the other groups. Serum ferritin and liver iron concentration did not differ among the animals that received chia ferritin and hephaestin expression was lower in experimental groups when compared with the control group. The peroxisome proliferator activated receptor expression was higher in animals fed with SD + C than in the control group. The expression of duodenal cytochrome B and divalent metal transporter 1 in the HFD + C group was higher and ferroportin was lower in the groups containing chia. Animals fed with chia showed similar iron bioavailability compared to animals fed with ferrous sulfate.

  20. The Bioavailability of Soluble Cigarette Smoke Extract Is Reduced through Interactions with Cells and Affects the Cellular Response to CSE Exposure.

    PubMed

    Bourgeois, Jeffrey S; Jacob, Jeeva; Garewal, Aram; Ndahayo, Renata; Paxson, Julia

    2016-01-01

    Cellular exposure to cigarette smoke leads to an array of complex responses including apoptosis, cellular senescence, telomere dysfunction, cellular aging, and neoplastic transformation. To study the cellular response to cigarette smoke, a common in vitro model exposes cultured cells to a nominal concentration (i.e. initial concentration) of soluble cigarette smoke extract (CSE). However, we report that use of the nominal concentration of CSE as the only measure of cellular exposure is inadequate. Instead, we demonstrate that cellular response to CSE exposure is dependent not only on the nominal concentration of CSE, but also on specific experimental variables, including the total cell number, and the volume of CSE solution used. As found in other similar xenobiotic assays, our work suggests that the effective dose of CSE is more accurately related to the amount of bioavailable chemicals per cell. In particular, interactions of CSE components both with cells and other physical factors limit CSE bioavailability, as demonstrated by a quantifiably reduced cellular response to CSE that is first modified by such interactions. This has broad implications for the nature of cellular response to CSE exposure, and for the design of in vitro assays using CSE.

  1. The Bioavailability of Soluble Cigarette Smoke Extract Is Reduced through Interactions with Cells and Affects the Cellular Response to CSE Exposure

    PubMed Central

    Bourgeois, Jeffrey S.; Jacob, Jeeva; Garewal, Aram; Ndahayo, Renata; Paxson, Julia

    2016-01-01

    Cellular exposure to cigarette smoke leads to an array of complex responses including apoptosis, cellular senescence, telomere dysfunction, cellular aging, and neoplastic transformation. To study the cellular response to cigarette smoke, a common in vitro model exposes cultured cells to a nominal concentration (i.e. initial concentration) of soluble cigarette smoke extract (CSE). However, we report that use of the nominal concentration of CSE as the only measure of cellular exposure is inadequate. Instead, we demonstrate that cellular response to CSE exposure is dependent not only on the nominal concentration of CSE, but also on specific experimental variables, including the total cell number, and the volume of CSE solution used. As found in other similar xenobiotic assays, our work suggests that the effective dose of CSE is more accurately related to the amount of bioavailable chemicals per cell. In particular, interactions of CSE components both with cells and other physical factors limit CSE bioavailability, as demonstrated by a quantifiably reduced cellular response to CSE that is first modified by such interactions. This has broad implications for the nature of cellular response to CSE exposure, and for the design of in vitro assays using CSE. PMID:27649082

  2. Selenium in edible mushrooms.

    PubMed

    Falandysz, Jerzy

    2008-01-01

    Selenium is vital to human health. This article is a compendium of virtually all the published data on total selenium concentrations, its distribution in fruitbody, bioconcentration factors, and chemical forms in wild-grown, cultivated, and selenium-enriched mushrooms worldwide. Of the 190 species reviewed (belonging to 21 families and 56 genera), most are considered edible, and a few selected data relate to inedible mushrooms. Most of edible mushroom species examined until now are selenium-poor (< 1 microg Se/g dry weight). The fruitbody of some species of wild-grown edible mushrooms is naturally rich in selenium; their occurrence data are reviewed, along with information on their suitability as a dietary source of selenium for humans, the impact of cooking and possible leaching out, the significance of traditional mushroom dishes, and the element's absorption rates and co-occurrence with some potentially problematic elements. The Goat's Foot (Albatrellus pes-caprae) with approximately 200 microg Se/g dw on average (maximum up to 370 microg/g dw) is the richest one in this element among the species surveyed. Several other representatives of the genus Albatrellus are also abundant in selenium. Of the most popular edible wild-grown mushrooms, the King Bolete (Boletus edulis) is considered abundant in selenium as well; on average, it contains approximately 20 microg Se/g dw (maximum up to 70 microg/g dw). Some species of the genus Boletus, such as B. pinicola, B. aereus, B. aestivalis, B. erythropus, and B. appendiculus, can also accumulate considerable amounts of selenium. Some other relatively rich sources of selenium include the European Pine Cone Lepidella (Amanita strobiliformis), which contains, on average, approximately 20 microg Se/g dw (up to 37 microg/g dw); the Macrolepiota spp., with an average range of approximately 5 to < 10 microg/g dw (an exception is M. rhacodes with < 10 microg/g dw); and the Lycoperdon spp., with an average of approximately 5

  3. Increased calcium bioavailability in mice fed genetically engineered plants lacking calcium oxalate

    USDA-ARS?s Scientific Manuscript database

    Bioavailable calcium affects bone formation and calcification. Here we investigate how a single gene mutation altering calcium partitioning in the model forage crop Medicago truncatula affects calcium bioavailability. Previously, the cod5 M. truncatula mutant was identified which contains identical ...

  4. Bioavailability Challenges Associated with Development of Anti-Cancer Phenolics

    PubMed Central

    Gao, Song; Hu, Ming

    2010-01-01

    Phenolics including many polyphenols and flavonoids have the potentials to become chemoprevention and chemotherapy agents. However, poor bioavailability limits their biological effects in vivo. This paper reviews the factors that affect phenolics absorption and their bioavailabilities from the points of view of their physicochemical properties and disposition in the gastrointestinal tract. The up-to-date research data suggested that solubility and metabolism are the primary reasons that limit phenolic aglycones’ bioavailability although stability and poor permeation may also contribute to the poor bioavailabilities of the glycosides. Future investigations should further optimize phenolics’ bioavailabilities and realize their chemopreventive and chemotherapeutic effects in vivo. PMID:20370701

  5. Bioavailability of metals in soils and sedimentes affected by old mining actitvities. The study case of the Portman bay (SE, Spain)

    NASA Astrophysics Data System (ADS)

    Martinez-Sanchez, Maria Jose; Agudo, Ines; Banegas, Ascension; Garcia-Lorenzo, Maria Luz; Gonzalez-Ciudad, Eva; Perez-Espinosa, Victor; Martinez-Lopez, Salvadora; Martinez, Lucia; Perz-Sirvent, Carmen

    2010-05-01

    A study on metal (Zn, Pb, Cd, Cu and As) mobilization and analysis of the health risk represented by ingestion from contaminated sediments in Portman Bay (SE Spain) was carried out. This zone has suffered a great impact from mining activity, since million tons of mine tailings were dumped into the bay for a long period, giving as a result the filling of the bay with them. The long-term deposition of metals in soils and sediments can lead to their accumulation and transport, while their toxicity depends on the mobility and bioavailability of a significant fraction of the metals. The ingestion of contaminated soil particles by grazing animals or young children may well represent a special exposure pathway for Pb, Cd and other hazardous metals. The aim of this study was to determine the bioaccessibility of Zn, Pb, Cd, Cu and As ,and the extent to which bioaccessibility is influenced by mineralogy in materials from this mining site as an indicator of the potential risk that metals pose to both environmental and human health. General analytical determinations (pH, particle size, organic matter, equivalent calcium carbonate content and mineralogical composition) were carried out to characterize the samples. The mineralogical composition was studied by X-ray diffraction (XRD), using a Philips PW3040 diffractometer with Cu-Kα. To determine the total metal content, the samples were digested in a Milestone ETHOS PLUS microwave, Zn, Pb, Cu and Cd contents were determined by electrothermal atomization atomic absorption spectrometry, while As was analysed by HG- AFS using an automated continuous flow hydride generation spectrometer. To assess bioaccessibility, the gastric solution was prepared according to the Standard Operating Procedure (SOP) developed by the Solubility/Bioavailability Research Consortium (SBRC). The mineralogical composition, corresponds to materials which have suffered a supergenic oxidation process which has been influenced by the presence of sea water

  6. Bioavailability of heavy metals, germanium and rare earth elements at Davidschacht dump-field in mine affected area of Freiberg (Saxony)

    NASA Astrophysics Data System (ADS)

    Midula, Pavol; Wiche, Oliver

    2016-04-01

    Bioavailability research presents an essential tool, in modern phytoremediation and phytomining technologies, allowing the estimation of plant available fractions of elements in soils. However, up to date, sufficient interdisciplinary knowledge on the biogeochemically impacted behavior of specific target elements, in particular Ge and REEs in mining affected soils and their uptake into strategically used plants is lacking. This presented work is focused on a correlation study between the concentrations of selected heavy metals, Ge and REEs in soils formed on the top of the dump-field of Davidschacht and the corresponding their concentrations in 12 vascular plant species. The mine-dump of Davidschacht, situated in the Freiberg (Saxony, Germany) municipality area was chosen as the study area, which has been considered to be a high contaminated enclave, due to the mining history of the region. In total 12 sampling sites with differing composition of plant species were selected. At each sampling site soil samples from a soil depth of 0 - 10 cm and samples of plant material (shoots) were taken. The soil samples were analysed for total concentration of elements, pH (H2O) and consequently analysed by 4-step sequential extraction (SE) to determine fractions of elements that are mobile (fraction 1), acid soluble (pH 5) (fraction 2), bound to organic and oxidizable matter (fraction 3) and bound to amorphic oxides (fraction 4). The plant material was decomposed by hydrofluoric acid in order to extract the elements. Concentrations of elements in soil extracts and digestion solutions were analysed by ICP-MS. For all species bioconcentration factor (BCF) was calculated of the total concentration of elements in order to investigate the bioaccumulation potential. Arsenic (As), cadmium (Cd) and lead (Pb) were chosen as the representative heavy metals. Within the REEs neodymium (Nd) and cerium (Ce) were selected as representatives for all REEs, since Nd and Ce correlated significant

  7. Selenium in Cattle: A Review.

    PubMed

    Mehdi, Youcef; Dufrasne, Isabelle

    2016-04-23

    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.

  8. 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.

  9. Aquatic Life Criterion - Selenium Documents

    EPA Pesticide Factsheets

    Documents pertaining to the 2016 Acute and Chronic Ambient Aquatic Life Water Quality Criteria for Selenium (Freshwater). These documents include what the safe levels of Selenium are in water for the majority of species.

  10. Flavonoid Bioavailability and Attempts for Bioavailability Enhancement

    PubMed Central

    Thilakarathna, Surangi H.; Rupasinghe, H. P. Vasantha

    2013-01-01

    Flavonoids are a group of phytochemicals that have shown numerous health effects and have therefore been studied extensively. Of the six common food flavonoid classes, flavonols are distributed ubiquitously among different plant foods whereas appreciable amounts of isoflavones are found in leguminous plant-based foods. Flavonoids have shown promising health promoting effects in human cell culture, experimental animal and human clinical studies. They have shown antioxidant, hypocholesterolemic, anti-inflammatory effects as well as ability to modulate cell signaling and gene expression related disease development. Low bioavailability of flavonoids has been a concern as it can limit or even hinder their health effects. Therefore, attempts to improve their bioavailability in order to improve the efficacy of flavonoids are being studied. Further investigations on bioavailability are warranted as it is a determining factor for flavonoid biological activity. PMID:23989753

  11. Deficient and excess dietary selenium levels affect growth performance, blood cells apoptosis and liver HSP70 expression in juvenile yellow catfish Pelteobagrus fulvidraco.

    PubMed

    Hu, Jun-Ru; Huang, Yan-Hua; Wang, Guo-Xia; Wu, Ying-Xia; Xian, Jian-An; Wang, An-Li; Cao, Jun-Ming

    2016-02-01

    We investigated the effects of deficient and excess dietary selenium (Se) on growth, blood cells apoptosis and liver heat shock protein 70 (HSP70) expression in juvenile yellow catfish (Pelteobagrus fulvidraco). After 8 weeks, yellow catfish (initial weight: 2.12 ± 0.01 g) fed isonitrogenous and isolipid diets containing <0.05 (deficient dietary Se) or 6.5 (excess dietary Se) mg Se/kg displayed a significantly lower weight gain ratio (WGR) than those fed a diet containing 0.23 (normal dietary Se) mg Se/kg. As dietary Se levels increased, liver Se concentration, glutathione peroxidase activity and the hepatosomatic index increased significantly. Plasma glucose concentration was highest in the normal treatment compared with the excess dietary Se treatment. Both deficient and excess dietary Se lead to increased reactive oxygen species (ROS) production and apoptosis ratio in blood cells, whereas only excess dietary Se increased their cytoplasmic free-Ca(2+) (CF-Ca(2+)) concentration. Excess dietary Se also resulted in the highest level of HSP70 expression, thereby possibly providing a protective mechanism against oxidative stress. These results indicate that both deficient and excess dietary Se restrained the growth of juvenile yellow catfish and caused oxidative stress. The overproduction of ROS may act as a signal molecule mediate apoptosis when dietary Se deficiency. Both ROS and CF-Ca(2+) were recorded when dietary Se excess, suggesting that Ca(2+) may be activated by Se and play a major role during Se-induced oxidative stress and cell apoptosis.

  12. Characterization of cytosolic glutathione peroxidase and phospholipid-hydroperoxide glutathione peroxidase genes in rainbow trout (Oncorhynchus mykiss) and their modulation by in vitro selenium exposure.

    PubMed

    Pacitti, D; Wang, T; Page, M M; Martin, S A M; Sweetman, J; Feldmann, J; Secombes, C J

    2013-04-15

    Selenium (Se) is an oligonutrient with both essential biological functions and recognized harmful effects. As the selenocysteine (SeCys) amino acid, selenium is integrated in several Se-containing proteins (selenoproteins), many of which are fundamental for cell homeostasis. Nevertheless, selenium may exert toxic effects at levels marginally above those required, mainly through the generation of reactive oxygen species (ROS). The selenium chemical speciation can strongly affect the bioavailability of this metal and its impact on metabolism, dictating the levels that can be beneficial or detrimental towards an organism. Glutathione peroxidase (GPxs) is the largest and the most studied selenoprotein family. Cytosolic glutathione peroxidase (cGPx, GPx1) and phospholipid hydroperoxide glutathione peroxidase (PHGPx, GPx4) are widely distributed throughout tissues, and play a pivotal role in regulating the oxidative status in the cell. In this study we have cloned GPx1 and GPx4 genes in rainbow trout (Oncorhynchus mykiss). The constitutive mRNA expression of these GPx genes was examined in 18 trout tissues and their responsiveness to Se availability was analysed using a rainbow trout liver cell line (RTL). An inorganic (sodium selenite, Na2SeO3) and organic (selenocysteine, Cys-Se-Se-Cys) selenocompound have been used as Se sources. GPx1 activity was also tested to verify the impact of transcript changes on the enzymatic function of these molecules. To understand if the results obtained from the transcript expression analysis were due to Se bioavailability or generation of ROS, the cytoxicity of the two selenocompounds was tested by measuring the impact of Se on cell membrane integrity. Lastly, Se availability was quantified by mass spectrophotometry to determine the amount of Se in the cell culture media, the Se background due to the foetal calf serum supplement and the contribution from the two selenocompounds used in the treatments. Three isoforms of genes for both

  13. Commentary: selenium study on endangered razorback sucker is flawed

    USGS Publications Warehouse

    Hamilton, Steven J.

    2005-01-01

    The razorback sucker (Xyrauchen texanus) is listed as federally endangered throughout its range. A massive recovery effort by the Recovery Implementation Program for Endangered Fish Species in the Upper Colorado River Basin has focused its efforts in the upper Colorado River. The upper Colorado River basin also has two locations that have been identified by the National Irrigation Water Quality Program as having substantial selenium contamination. Selenium is toxic to fishes, affecting reproductive success. Thus, there is concern about potential effects of selenium on the endangered razorback sucker. Two sets of studies have investigated the effects of selenium on razorback suckers, but study results are conflicting. This commentary evaluates studies that claim selenium is not a problem for razorback sucker. We find that study bias was so pervasive that purported conclusions were unwarranted. Contaminated control water, older life stages of fish tested, lack of methodology for analysis of selenium in water, diet, or fish, use of rotifer food, low feeding rates, low growth rates of fish, and improper storage of site waters resulted in an apparent erroneous linkage of high selenium in whole-body residues with no adverse effects.

  14. Commentary: selenium study on endangered razorback sucker is flawed.

    PubMed

    Hamilton, Steven J

    2005-07-01

    The razorback sucker (Xyrauchen texanus) is listed as federally endangered throughout its range. A massive recovery effort by the Recovery Implementation Program for Endangered Fish Species in the Upper Colorado River Basin has focused its efforts in the upper Colorado River. The upper Colorado River basin also has two locations that have been identified by the National Irrigation Water Quality Program as having substantial selenium contamination. Selenium is toxic to fishes, affecting reproductive success. Thus, there is concern about potential effects of selenium on the endangered razorback sucker. Two sets of studies have investigated the effects of selenium on razorback suckers, but study results are conflicting. This commentary evaluates studies that claim selenium is not a problem for razorback sucker. We find that study bias was so pervasive that purported conclusions were unwarranted. Contaminated control water, older life stages of fish tested, lack of methodology for analysis of selenium in water, diet, or fish, use of rotifer food, low feeding rates, low growth rates of fish, and improper storage of site waters resulted in an apparent erroneous linkage of high selenium in whole-body residues with no adverse effects.

  15. Optimized mixed oils remarkably reduce the amount of surfactants in microemulsions without affecting oral bioavailability of ibuprofen by simultaneously enlarging microemulsion areas and enhancing drug solubility.

    PubMed

    Chen, Yizhen; Tuo, Jue; Huang, Huizhi; Liu, Dan; You, Xiuhua; Mai, Jialuo; Song, Jiaqi; Xie, Yanqi; Wu, Chuanbin; Hu, Haiyan

    2015-06-20

    The toxicity and irritation associated with high amounts of surfactants restrict the extensive utilization of microemulsions. To address these shortcomings, employing mixed oils to enlarge microemulsion areas therefore reducing surfactant contents is a promising strategy. However, what kinds of mixed oils are more efficient in enlarging microemulsion areas still remains unclear. In this research, we found that the chain length and degree of unsaturation of oils play a key role in enlarging microemulsion areas. The combination of moderate chain saturated oil caprylic/capric triglyceride (GTCC) with long chain unsaturated oil glycerol trioleate significantly increased the microemulsion areas. Solubility of ibuprofen in the mixed oils was unexpectedly and remarkably increased (almost 300mg/mL) compared with that (around 100mg/mL) of the single oil (GTCC), which also resulted in greatly increased solubility of ibuprofen in mixed oils-containing microemulsions. By optimizing the mixed oil formulation, the absolute amount of surfactant in drug-loaded microemulsions was reduced but increased drug oral bioavailability in rats was maintained. It could be concluded that the combined use of moderate chain oils and long chain unsaturated oils could not only acquire enlarged microemulsion areas but also enhanced drug solubility, therefore doubly reducing surfactant amount, which is extremely beneficial for developing safe microemulsions. Copyright © 2015. Published by Elsevier B.V.

  16. Sediment contamination, bioavailability and toxicity of sediments affected by an acute oil spill: Four years after the sinking of the tanker Prestige (2002).

    PubMed

    Morales-Caselles, C; Kalman, J; Micaelo, C; Ferreira, A M; Vale, C; Riba, I; Delvalls, T A

    2008-04-01

    Sediment contamination and three bioassays were used to determine the sediment quality four years after an oil spill (Prestige, 2002): the Microtox test, a 10-day bioassay using the amphipod Ampelisca brevicornis, and a polychaete 10-day toxicity test with the lugworm Arenicola marina. In addition, bioaccumulation of PAHs was examined in the polychaete after 10 days of exposure. The results obtained from the toxicity tests and bioaccumulation analyses were statistically compared to the sediment chemical data, in order to assess the bioavailability of the contaminants, their effects, and their relationship with the oil spill. The sediments studied were from two areas of the Galician Coast (NW Spain): the Bay of Corme-Laxe and the Cíes Island, located in the Atlantic Island National Park. The results point to a decrease in contamination with respect to previous studies and to the disappearance of the acute toxicity four years after the oil spill. However an important bioaccumulation of PAHs was detected in the organisms exposed to sediments from Corme-Laxe, suggesting that despite the recovery of the environmental quality of the area, effects in the biota might be occurring.

  17. 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

  18. Assessment of toxicity of selenium and cadmium selenium quantum dots: A review.

    PubMed

    Sharma, Virender K; McDonald, Thomas J; Sohn, Mary; Anquandah, George A K; Pettine, Maurizio; Zboril, Radek

    2017-12-01

    This paper reviews the current understanding of the toxicity of selenium (Se) to terrestrial mammalian and aquatic organisms. Adverse biological effects occur in the case of Se deficiencies, associated with this element having essential biological functions and a narrow window between essentiality and toxicity. Several inorganic species of Se (-2, 0, +4, and +6) and organic species (monomethylated and dimethylated) have been reported in aquatic systems. The toxicity of Se in any given sample depends not only on its speciation and concentration, but also on the concomitant presence of other compounds that may have synergistic or antagonistic effects, affecting the target organism as well, usually spanning 2 or 3 orders of magnitude for inorganic Se species. In aquatic ecosystems, indirect toxic effects, linked to the trophic transfer of excess Se, are usually of much more concern than direct Se toxicity. Studies on the toxicity of selenium nanoparticles indicate the greater toxicity of chemically generated selenium nanoparticles relative to selenium oxyanions for fish and fish embryos while oxyanions of selenium have been found to be more highly toxic to rats as compared to nano-Se. Studies on polymer coated Cd/Se quantum dots suggest significant differences in toxicity of weathered vs. non-weathered QD's as well as a significant role for cadmium with respect to toxicity. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. 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.

  20. Iodine and Selenium Biofortification with Additional Application of Salicylic Acid Affects Yield, Selected Molecular Parameters and Chemical Composition of Lettuce Plants (Lactuca sativa L. var. capitata)

    PubMed Central

    Smoleń, Sylwester; Kowalska, Iwona; Czernicka, Małgorzata; Halka, Mariya; Kęska, Kinga; Sady, Włodzimierz

    2016-01-01

    Iodine (I) and selenium (Se) are included in the group of beneficial elements. They both play important roles in humans and other animals, particularly in the regulation of thyroid functioning. A substantial percentage of people around the world suffer from health disorders related to the deficiency of these elements in the diet. Salicylic acid (SA) is a compound similar to phytohormones and is known to improve the efficiency of I biofortification of plants. The influence of SA on Se enrichment of plants has not, however, been recognized together with its effect on simultaneous application of I and Se to plants. Two-year studies (2014–2015) were conducted in a greenhouse with hydroponic cultivation of lettuce in an NFT (nutrient film technique) system. They included the application of I (as KIO3), Se (as Na2SeO3) and SA into the nutrient solution. KIO3 was used at a dose of 5 mg I⋅dm-3 (i.e., 39.4 μM I), while Na2SeO3 was 0.5 mg Se⋅dm-3 (i.e., 6.3 μM Se). SA was introduced at three doses: 0.1, 1.0, and 10.0 mg⋅dm-3 nutrient solutions, equivalent to 0.724, 7.24, and 72.4 μM SA, respectively. The tested combinations were as follows: (1) control, (2) I + Se, (3) I + Se + 0.1 mg SA⋅dm-3, (4) I + Se + 1.0 mg SA⋅dm-3 and (5) I + Se + 10.0 mg SA⋅dm-3. The applied treatments had no significant impact on lettuce biomass (leaves and roots). Depending on the dose, a diverse influence of SA was noted with respect to the efficiency of I and Se biofortification; chemical composition of leaves; and mineral nutrition of lettuce plants, including the content of macro- and microelements and selenocysteine methyltransferase (SMT) gene expression. SA application at all tested doses comparably increased the level of selenomethionine (SeMet) and decreased the content of SA in leaves. PMID:27803709

  1. Iodine and Selenium Biofortification with Additional Application of Salicylic Acid Affects Yield, Selected Molecular Parameters and Chemical Composition of Lettuce Plants (Lactuca sativa L. var. capitata).

    PubMed

    Smoleń, Sylwester; Kowalska, Iwona; Czernicka, Małgorzata; Halka, Mariya; Kęska, Kinga; Sady, Włodzimierz

    2016-01-01

    Iodine (I) and selenium (Se) are included in the group of beneficial elements. They both play important roles in humans and other animals, particularly in the regulation of thyroid functioning. A substantial percentage of people around the world suffer from health disorders related to the deficiency of these elements in the diet. Salicylic acid (SA) is a compound similar to phytohormones and is known to improve the efficiency of I biofortification of plants. The influence of SA on Se enrichment of plants has not, however, been recognized together with its effect on simultaneous application of I and Se to plants. Two-year studies (2014-2015) were conducted in a greenhouse with hydroponic cultivation of lettuce in an NFT (nutrient film technique) system. They included the application of I (as KIO3), Se (as Na2SeO3) and SA into the nutrient solution. KIO3 was used at a dose of 5 mg I⋅dm(-3) (i.e., 39.4 μM I), while Na2SeO3 was 0.5 mg Se⋅dm(-3) (i.e., 6.3 μM Se). SA was introduced at three doses: 0.1, 1.0, and 10.0 mg⋅dm(-3) nutrient solutions, equivalent to 0.724, 7.24, and 72.4 μM SA, respectively. The tested combinations were as follows: (1) control, (2) I + Se, (3) I + Se + 0.1 mg SA⋅dm(-3), (4) I + Se + 1.0 mg SA⋅dm(-3) and (5) I + Se + 10.0 mg SA⋅dm(-3). The applied treatments had no significant impact on lettuce biomass (leaves and roots). Depending on the dose, a diverse influence of SA was noted with respect to the efficiency of I and Se biofortification; chemical composition of leaves; and mineral nutrition of lettuce plants, including the content of macro- and microelements and selenocysteine methyltransferase (SMT) gene expression. SA application at all tested doses comparably increased the level of selenomethionine (SeMet) and decreased the content of SA in leaves.

  2. Mineral surfaces and bioavailability of heavy metals: A molecular-scale perspective

    PubMed Central

    Brown, Gordon E.; Foster, Andrea L.; Ostergren, John D.

    1999-01-01

    There is a continual influx of heavy metal contaminants and pollutants into the biosphere from both natural and anthropogenic sources. A complex variety of abiotic and biotic processes affects their speciation and distribution, including adsorption onto and desorption from mineral surfaces, incorporation in precipitates or coprecipitates, release through the dissolution of minerals, and interactions with plants and microbes. Some of these processes can effectively isolate heavy metals from the biosphere, whereas others cause their release or transformation to different species that may be more (or less) bioavailable and/or toxic to organisms. Here we focus on abiotic adsorption and precipitation or coprecipitation processes involving the common heavy metal contaminant lead and the metalloids arsenic and selenium in mine tailings and contaminated soils. We have used extremely intense x-rays from synchrotron sources and a structure-sensitive method known as x-ray absorption fine structure (XAFS) spectroscopy to determine the molecular-level speciation of these elements at concentrations of 50 to several thousand ppm in the contaminated environmental samples as well as in synthetic sorption samples. Our XAFS studies of As and Pb in the mine tailings show that up to 50% of these contaminants in the samples studied may be present as adsorbed species on mineral surfaces, which makes them potentially more bioavailable than when present in sparingly soluble solid phases. Our XAFS studies of Se(VI) sorption on Fe2+-containing sulfates show that this element undergoes redox reactions that transform it into less bioavailable and less toxic species. This type of information on molecular-level speciation of heavy metal and metalloid contaminants in various environmental settings is needed to prioritize remediation efforts and to assess their potential hazard to humans and other organisms. PMID:10097048

  3. 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

  4. Biological effects of a nano red elemental selenium.

    PubMed

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

    2001-01-01

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

  5. EFFECTS OF DIFFERENT FORMS OF ORGANIC CARBON ON THE PARTITIONING AND BIOAVAILABILITY OF NONPHENYL

    EPA Science Inventory

    Oxygenated nonpolar organic contaminants (NOCs) are underrepresented in studies of the partitioning and bioavailability of NOCs, including nonylphenol. In this investigation, we evaluated the toxicity, partitioning, and bioavailability of nonylphenol as affected by different form...

  6. Relative Bioavailability and Bioaccessability and Speciation of Arsenic in Contaminated Soils

    EPA Science Inventory

    Background: Assessment of soil arsenic (As) bioavailability may profoundly affect the extent of remediation required at contaminated sites by improving human exposure estimates. Because small adjustments in soil As bioavailability estimates can significantly alter risk assessment...

  7. Relative Bioavailability and Bioaccessability and Speciation of Arsenic in Contaminated Soils

    EPA Science Inventory

    Background: Assessment of soil arsenic (As) bioavailability may profoundly affect the extent of remediation required at contaminated sites by improving human exposure estimates. Because small adjustments in soil As bioavailability estimates can significantly alter risk assessment...

  8. Seasonal variation in selenium status of different classes of grazing goats in a semi-arid region of Pakistan.

    PubMed

    Khan, Z I; Ashraf, M; Hussain, A; Koyro, H-W; Huchzermeyer, B

    2005-12-01

    The selenium status of three different classes of goats ((i) female lactating, (ii) female non-lactating, and (iii) male goats) grazing semi-arid pasture in the southern part of the Punjab province, Pakistan and that of selenium concentration of soil and dietary sources, ingested by those animals were investigated during two different seasons of the year (winter and summer). Soil, forage, feed, water from the pasture and blood plasma, urine, faeces, and (if applicable) milk from these goats were collected fortnightly. The samples were analyzed for selenium concentrations. Soil selenium showed both seasonal and sampling periods effect on its concentration while forage selenium was affected only by the seasonal changes. No significant effect of seasons or fortnights on feed selenium level was observed. In fecal samples selenium concentration in lactating and non-lactating and plasma of male goats were affected by sampling periods. While fecal selenium in male goats showed significant effect on its concentration both seasonal and within fortnights. Severe deficient level of soil selenium during both seasons and marginal deficient level of forage selenium during summer were observed. Selenium concentrations in feed slightly exceeded the requirements of ruminants in feed during both seasons of the year. Plasma selenium concentrations in all goat classes were higher in winter than that in summer showing no seasonal or fortnight variation and its concentration was slightly lower in lactating goats as compared to other classes. On the bases of these results, it is concluded that overall selenium status of the goats based on plasma selenium concentration may be considered adequate mainly due to the mineral supplement provided all over the year, since soil and forage selenium concentrations were low to deficient.

  9. Selenium and Selenoprotein Deficiencies Induce Widespread Pyogranuloma Formation in Mice, while High Levels of Dietary Selenium Decrease Liver Tumor Size Driven by TGFα

    PubMed Central

    Zhong, Nianxin; Ward, Jerrold M.; Perella, Christine M.; Hoffmann, Victoria J.; Rogers, Keith; Combs, Gerald F.; Schweizer, Ulrich; Merlino, Glenn; Gladyshev, Vadim N.; Hatfield, Dolph L.

    2013-01-01

    Changes in dietary selenium and selenoprotein status may influence both anti- and pro-cancer pathways, making the outcome of interventions different from one study to another. To characterize such outcomes in a defined setting, we undertook a controlled hepatocarcinogenesis study involving varying levels of dietary selenium and altered selenoprotein status using mice carrying a mutant (A37G) selenocysteine tRNA transgene (TrsptG37) and/or a cancer driver TGFα transgene. The use of TrsptG37 altered selenoprotein expression in a selenoprotein and tissue specific manner and, at sufficient dietary selenium levels, separate the effect of diet and selenoprotein status. Mice were maintained on diets deficient in selenium (0.02 ppm selenium) or supplemented with 0.1, 0.4 or 2.25 ppm selenium or 30 ppm triphenylselenonium chloride (TPSC), a non-metabolized selenium compound. TrsptG37 transgenic and TGFα/TrsptG37 bi-transgenic mice subjected to selenium-deficient or TPSC diets developed a neurological phenotype associated with early morbidity and mortality prior to hepatocarcinoma development. Pathology analyses revealed widespread disseminated pyogranulomatous inflammation. Pyogranulomas occurred in liver, lungs, heart, spleen, small and large intestine, and mesenteric lymph nodes in these transgenic and bi-transgenic mice. The incidence of liver tumors was significantly increased in mice carrying the TGFα transgene, while dietary selenium and selenoprotein status did not affect tumor number and multiplicity. However, adenoma and carcinoma size and area were smaller in TGFα transgenic mice that were fed 0.4 and 2.25 versus 0.1 ppm of selenium. Thus, selenium and selenoprotein deficiencies led to widespread pyogranuloma formation, while high selenium levels inhibited the size of TGFα–induced liver tumors. PMID:23460847

  10. [Bioavailability of antiinflammatory drugs].

    PubMed

    Cochereau, I

    2000-05-01

    Bioavailability is one of the major factors for therapeutic efficacy. The bioavailability of antiinflammatory drugs depends on the status of the eye (degree of inflammation, vitrectomy, aphakia) and on the drug (route of administration, regimen, concentration and presentation). The bioavailability of steroid drops increases with acetate compounds, frequency of administration, concentration and contact time. Peribulbar injections provide a long-delivery system but with a significant systemic diffusion. Intravitreal steroids have only a local effect due to the very low doses injected. The bioavailability of non steroidal antiinflammatory drugs is variable, but their effects are similar. Antimetabolites such as 5-fluorouracil or mitomycin C have short half-lives, but mitomycin C must be rinsed after use due to its toxicity.

  11. Selenium and mercury molar ratios in commercial fish from New Jersey and Illinois: Variation within species and relevance to risk communication

    PubMed Central

    Burger, Joanna; Gochfeld, Michael

    2015-01-01

    There is an emerging consensus that people consuming large amounts of fish with selenium:mercury ratios below 1 may be at higher risk from mercury toxicity. As the relative amount of selenium increases compared to mercury, risk may be lowered, but it is unclear how much excess selenium is required. It would be useful if the selenium:mercury ratio was relatively consistent within a species, but this has not been the case in our studies of wild-caught fish. Since most people in developed countries and urban areas obtain their fish and other seafood commercially, we examined selenium:mercury molar ratios in commercial fish purchased in stores and fish markets in central New Jersey and Chicago. There was substantial interspecific and intraspecific variation in molar ratios. Across species the selenium:mercury molar ratio decreased with increasing mean mercury levels, but selenium variation also contributed to the ratio. Few samples had selenium:mercury molar ratios below 1, but there was a wide range in ratios, complicating the interpretation for use in risk management and communication. Before ratios can be used in risk management, more information is needed on mercury:selenium interactions and mutual bioavailability, and on the relationship between molar ratios and health outcomes. Further, people who are selenium deficient may be more at risk from mercury toxicity than others. PMID:23541437

  12. Selenium Metabolism in Cancer Cells: The Combined Application of XAS and XFM Techniques to the Problem of Selenium Speciation in Biological Systems

    PubMed Central

    Weekley, Claire M.; Aitken, Jade B.; Finney, Lydia; Vogt, Stefan; Witting, Paul K.; Harris, Hugh H.

    2013-01-01

    Determining the speciation of selenium in vivo is crucial to understanding the biological activity of this essential element, which is a popular dietary supplement due to its anti-cancer properties. Hyphenated techniques that combine separation and detection methods are traditionally and effectively used in selenium speciation analysis, but require extensive sample preparation that may affect speciation. Synchrotron-based X-ray absorption and fluorescence techniques offer an alternative approach to selenium speciation analysis that requires minimal sample preparation. We present a brief summary of some key HPLC-ICP-MS and ESI-MS/MS studies of the speciation of selenium in cells and rat tissues. We review the results of a top-down approach to selenium speciation in human lung cancer cells that aims to link the speciation and distribution of selenium to its biological activity using a combination of X-ray absorption spectroscopy (XAS) and X-ray fluorescence microscopy (XFM). The results of this approach highlight the distinct fates of selenomethionine, methylselenocysteine and selenite in terms of their speciation and distribution within cells: organic selenium metabolites were widely distributed throughout the cells, whereas inorganic selenium metabolites were compartmentalized and associated with copper. New data from the XFM mapping of electrophoretically-separated cell lysates show the distribution of selenium in the proteins of selenomethionine-treated cells. Future applications of this top-down approach are discussed. PMID:23698165

  13. Selenium metabolism in cancer cells: the combined application of XAS and XFM techniques to the problem of selenium speciation in biological systems.

    PubMed

    Weekley, Claire M; Aitken, Jade B; Finney, Lydia; Vogt, Stefan; Witting, Paul K; Harris, Hugh H

    2013-05-21

    Determining the speciation of selenium in vivo is crucial to understanding the biological activity of this essential element, which is a popular dietary supplement due to its anti-cancer properties. Hyphenated techniques that combine separation and detection methods are traditionally and effectively used in selenium speciation analysis, but require extensive sample preparation that may affect speciation. Synchrotron-based X-ray absorption and fluorescence techniques offer an alternative approach to selenium speciation analysis that requires minimal sample preparation. We present a brief summary of some key HPLC-ICP-MS and ESI-MS/MS studies of the speciation of selenium in cells and rat tissues. We review the results of a top-down approach to selenium speciation in human lung cancer cells that aims to link the speciation and distribution of selenium to its biological activity using a combination of X-ray absorption spectroscopy (XAS) and X-ray fluorescence microscopy (XFM). The results of this approach highlight the distinct fates of selenomethionine, methylselenocysteine and selenite in terms of their speciation and distribution within cells: organic selenium metabolites were widely distributed throughout the cells, whereas inorganic selenium metabolites were compartmentalized and associated with copper. New data from the XFM mapping of electrophoretically-separated cell lysates show the distribution of selenium in the proteins of selenomethionine-treated cells. Future applications of this top-down approach are discussed.

  14. 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...

  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. Biomarkers of selenium status

    USDA-ARS?s Scientific Manuscript database

    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...

  18. 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.

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

    PubMed

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

    2014-08-01

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

  20. Geologic and Anthropogenic Controls on Selenium and Nitrate Loading to Southern California Streams

    NASA Astrophysics Data System (ADS)

    Hibbs, B. J.; Ellis, A. S.

    2009-12-01

    concentrations of nitrate in leachate, possibly from accumulation from atmospheric fallout. Leachate from non-weathered Miocene rock generally had low nitrate concentrations and low selenium. Miocene shales are exposed in vast areas of Southern California. We are undertaking regional studies to determine if other Southern California Watersheds are affected by elevated nitrate and selenium concentrations, and where selenium may threaten habitat.

  1. 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.

  2. Selenium in mainstream and sidestream smoke of cigarettes containing fly ash-grown tobacco

    SciTech Connect

    Gutenmann, W.H.; Lisk, D.J.; Shane, B.S.; Hoffmann, D.; Adams, J.D.

    1987-01-01

    The quantities of selenium, tar and nicotine present in mainstream (MS) and sidestream (SS) smoke of machine-smoked cigarettes was studied. The cigarettes were prepared from tobacco purposely cultured on fly ash-amended soil so as to increase its selenium concentration. Selenium concentration was found to be the same in the gaseous phase of both MS and SS smoke, but its concentration was significantly higher (p less than 0.05) in the particulate matter of the MS smoke. Tar was higher in MS smoke and nicotine in SS smoke. Factors affecting selenium concentrations in tobacco and its possible environmental significance are discussed.

  3. Bioavailability of bioactive food compounds: a challenging journey to bioefficacy

    PubMed Central

    Rein, Maarit J.; Renouf, Mathieu; Cruz‐Hernandez, Cristina; Actis‐Goretta, Lucas; Thakkar, Sagar K.; da Silva Pinto, Marcia

    2013-01-01

    Bioavailability is a key step in ensuring bioefficacy of bioactive food compounds or oral drugs. Bioavailability is a complex process involving several different stages: liberation, absorption, distribution, metabolism and elimination phases (LADME). Bioactive food compounds, whether derived from various plant or animal sources, need to be bioavailable in order to exert any beneficial effects. Through a better understanding of the digestive fate of bioactive food compounds we can impact the promotion of health and improvement of performance. Many varying factors affect bioavailability, such as bioaccessibility, food matrix effect, transporters, molecular structures and metabolizing enzymes. Bioefficacy may be improved through enhanced bioavailability. Therefore, several technologies have been developed to improve the bioavailability of xenobiotics, including structural modifications, nanotechnology and colloidal systems. Due to the complex nature of food bioactive compounds and also to the different mechanisms of absorption of hydrophilic and lipophilic bioactive compounds, unravelling the bioavailability of food constituents is challenging. Among the food sources discussed during this review, coffee, tea, citrus fruit and fish oil were included as sources of food bioactive compounds (e.g. (poly)phenols and polyunsaturated fatty acids (PUFAs)) since they are examples of important ingredients for the food industry. Although there are many studies reporting on bioavailability and bioefficacy of these bioactive food components, understanding their interactions, metabolism and mechanism of action still requires extensive work. This review focuses on some of the major factors affecting the bioavailability of the aforementioned bioactive food compounds. PMID:22897361

  4. Selenium supplementation for Hashimoto's thyroiditis.

    PubMed

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

    2013-06-06

    selenite 200 μg plus titrated LT4 compared with placebo plus titrated LT4 (relative risk (RR) 4.67, 95% confidence interval (CI) 1.61 to 13.50; P = 0.004; 36 participants; number needed to treat (NNT) = 2 (95% CI 2 to 3)).Selenomethionine 200 μg reduced the serum levels of anti-thyroid peroxidase antibodies compared with placebo in two studies (mean difference (MD) -917 U/mL, 95% CI -1056 to -778; P < 0.001; 85 participants) and (MD -345 IU/mL, 95% CI -359 to -331; P < 0.001; 169 participants). Pooling of the studies was not feasible due to marked clinical heterogeneity (I(2) = 99%). In a further comparison within the first study where selenomethionine was combined with LT4 the reduction in TPO antibodies was even more noticeable (MD -1508 U/mL, 95% CI -1671 to -1345; P < 0.001; 86 participants). In a third study, where LT4 was added to both intervention arms, a reduction in serum levels of anti-thyroid peroxidase antibodies favoured the selenomethionine arm as well (MD -235 IU/mL, 95% CI -374 to -95; P = 0.001; 88 participants). Although the changes from baseline were statistically significant in these three studies, their clinical relevance is unclear. Serum antibodies were not statistically significantly affected in the study comparing sodium selenite 200 μg plus titrated LT4 with placebo plus titrated LT4 (MD -25, 95% CI -181 to 131; P = 0.75; 36 participants).Adverse events were reported in two studies (1 of 85 and 1 of 88 participants, respectively). Selenium supplementation did not appear to have a statistically significant impact on the incidence of adverse events (RR 2.93, 95% CI 0.12 to 70.00; and RR 2.63, 95% CI 0.11 to 62.95). Results of these four studies show that evidence to support or refute the efficacy of selenium supplementation in people with Hashimoto's thyroiditis is incomplete. The current level of evidence for the efficacy of selenium supplementation in the management of people with Hashimoto's thyroiditis is based on four randomised controlled

  5. Selenium incorporation using recombinant techniques.

    PubMed

    Walden, Helen

    2010-04-01

    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.

  6. Integrating bioavailability approaches into waste rock evaluations

    USGS Publications Warehouse

    Ranville, James F.; Blumenstein, E. P.; Adams, Michael J.; Choate, LaDonna M.; Smith, Kathleen S.; Wildeman, Thomas R.

    2006-01-01

    The presence of toxic metals in soils affected by mining, industry, agriculture and urbanization, presents problems to human health, the establishment and maintenance of plant and animal habitats, and the rehabilitation of affected areas. A key to managing these problems is predicting the fraction of metal in a given soil that will be biologically labile, and potentially harmful ('bioavailable'). The molecular form of metals and metalloids, particularly the uncomplexed (free) form, controls their bioavailability and toxicity in solution. One computational approach for determining bioavailability, the biotic ligand model (BLM), takes into account not only metal complexation by ligands in solution, but also competitive binding of hardness cations (Ca 2+,Mg 2+,) and metal ions to biological receptor sites. The more direct approach to assess bioavailability is to explicitly measure the response of an organism to a contaminant. A number of microbial enzyme tests have been developed to assess the impact of pollution in a rapid and procedurally simple way. These different approaches in making bioavailability predictions may have value in setting landuse priorities, remediation goals, and habitat reclamation strategies.

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

    USDA-ARS?s Scientific Manuscript database

    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...

  8. Mammary tumorigenesis causes bone loss and dietary selenium supplementation does not affect such bone loss in male MMTV-PyMT mice

    USDA-ARS?s Scientific Manuscript database

    Cancer progression is accompanied by wasting that eventually results in cachexia characterized by significant weight loss and multi-organ functional failures. Limited clinical trials indicate that bone is adversely affected by cancer-associated wasting. To determine the effects of breast cancer on...

  9. 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.

  10. Dissociation of the genotoxic and growth inhibitory effects of selenium.

    PubMed

    Lu, J; Jiang, C; Kaeck, M; Ganther, H; Vadhanavikit, S; Ip, C; Thompson, H

    1995-07-17

    The effects of forms of selenium compounds that enter the cellular selenium metabolic pathway at different points were investigated in a mouse mammary carcinoma cell line. The goal of these experiments was to determine if the genotoxicity of selenium, defined as its ability to induce DNA single-strand breaks, could be dissociated from activities proposed to account for its cancer inhibitory activity. The results demonstrated that growth inhibition, measured as inhibition of cell proliferation and induction of cell death, was induced by all the forms of selenium evaluated. However, sodium selenite and sodium selenide, which are metabolized predominantly to hydrogen selenide, caused the rapid induction of DNA single-strand breaks as an early event that preceded growth inhibition. Interestingly methylselenocyanate and Se-methylselenocysteine, which are initially metabolized predominantly to methylselenol, induced growth inhibition in the absence of DNA single-strand breakage. Differences in the time course of selenium retention, in the occurrence of membrane damage, and in the induction of morphological changes by selenite versus methylselenocyanate were noted. Collectively, these data indicate that different pathways affecting cell proliferation and cell death are induced depending on whether selenium undergoes metabolism predominantly to hydrogen selenide or to methylselenol.

  11. 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).

  12. Metabolism of manganese, iron, copper, and selenium in calves

    SciTech Connect

    Ho, S.Y.

    1981-01-01

    Sixteen male Holstein calves were used to study manganese and iron metabolism. The calves were fed one of the following diets for 18 days: control, control + iron, control + manganese, and control + iron and manganese. All calves were dosed orally with manganese-54. Tissue concentrations of manganese, iron and manganese-54 were determined. Small intestinal iron was lower in calves fed the high manganese diet than in controls. Tissue manganese-54 was lower in calves fed a high manganese diet. Fecal manganese content increased in calves fed both high manganese and high manganese-high iron diets. Serum total iron was not affected by the dietary treatments. To study the effects of high dietary levels of copper and selenium on the intracellular distributions of these two elements in liver and kidney cytosol, calves were fed one of four diets for 15 days. These were 0 and 100 ppM supplemental copper and 0 and 1 ppM added selenium. The control diet containing 0.1 ppM of selenium and 15 ppM of copper. All calves were orally dosed 48 hrs prior to sacrifice with selenium-75. A high copper diet increased copper concentrations in all intracellular liver fractions and most kidney fractions. Only the effects in the liver were significant. Less copper was found in the mitochondria fractions in liver and kidney of calves fed a high selenium diet. Three major copper-binding protein peaks were separated from the soluble fractions of calf liver and kidney. Peak 1 appeared to be the major copper-binding protein in liver and kidney cytosol of copper-loaded animals. Added selenium alone or in combination with copper accentuated the copper accumulation in this peak. Most of selenium-75 was recovered in the same peak as the copper. The results of this experiment indicated that the large molecular proteins in liver and kidney cytosol of calves play an important role in copper and selenium-75 metabolism. (ERB)

  13. Acute Selenium Toxicity Associated With a Dietary Supplement

    PubMed Central

    MacFarquhar, Jennifer K.; Broussard, Danielle L.; Melstrom, Paul; Hutchinson, Richard; Wolkin, Amy; Martin, Colleen; Burk, Raymond F.; Dunn, John R.; Green, Alice L.; Hammond, Roberta; Schaffner, William; Jones, Timothy F.

    2011-01-01

    Background Selenium is an element necessary for normal cellular function, but it can have toxic effects at high doses. We investigated an outbreak of acute selenium poisoning. Methods A case was defined as the onset of symptoms of selenium toxicity in a person within 2 weeks after ingesting a dietary supplement manufactured by “Company A,” purchased after January 1, 2008. We conducted case finding, administered initial and 90-day follow-up questionnaires to affected persons, and obtained laboratory data where available. Results The source of the outbreak was identified as a liquid dietary supplement that contained 200 times the labeled concentration of selenium. Of 201 cases identified in 10 states, 1 person was hospitalized. The median estimated dose of selenium consumed was 41 749 μg/d (recommended dietary allowance is 55 μg/d). Frequently reported symptoms included diarrhea (78%), fatigue (75%), hair loss (72%), joint pain (70%), nail discoloration or brittleness (61%), and nausea (58%). Symptoms persisting 90 days or longer included fingernail discoloration and loss (52%), fatigue (35%), and hair loss (29%). The mean initial serum selenium concentration of 8 patients was 751 μg/L (reference range, ≤125 μg/L). The mean initial urine selenium concentration of 7 patients was 166 μg/24 h (reference range, ≤55 μg/24 h). Conclusions Toxic concentrations of selenium in a liquid dietary supplement resulted in a widespread outbreak. Had the manufacturers been held to standards used in the pharmaceutical industry, it may have been prevented. PMID:20142570

  14. Interspecific and intraspecific variation in selenium:mercury molar ratios in saltwater fish from the Aleutians: Potential protection on mercury toxicity by selenium

    PubMed Central

    Burger, Joanna; Gochfeld, Michael; Jeitner, Christian; Donio, Mark; Pittfield, Taryn

    2014-01-01

    A number of factors affect the consumption risk from mercury in fish, including mercury levels, seasonal patterns of mercury concentrations, human consumption patterns, and sensitive populations (e.g. pregnant women, fetuses, young children, and yet unknown genetic factors). Recently the protective effects of selenium on methylmercury toxicity have been publicized, particularly for saltwater fish. We examine levels of mercury and selenium in several species of fish and seabirds from the Aleutians (Alaska), determine selenium:mercury molar ratios, and examine species-specific and individual variation in the ratios as a means of exploring the use of the ratio in risk assessment and risk management. Variation among species was similar for mercury and selenium. There was significant inter-specific and intraspecific variation in selenium:mercury molar ratios for fish, and for birds. The mean selenium:mercury molar ratios for all fish and bird species were above 1, meaning there was an excess of selenium relative to mercury. It has been suggested that an excess of selenium confers some protective advantage for salt water fish, although the degree of excess necessary is unclear. The selenium:mercury molar ratio was significantly correlated negatively with total length for most fish species, but not for dolly varden. Some individuals of Pacific cod, yellow irish lord, rock greenling, Pacific halibut, dolly varden, and to a lesser extent, flathead sole, had selenium:mercury ratios below 1. No bird muscle had an excess of mercury (ratio below 1), and only glaucous-winged gull and pigeon guillemot had ratios between 1 and 5. There was a great deal of variation in selenium:mercury molar ratios within fish species, and within bird species, making it difficult and impractical to use these ratios in risk assessment or management, for fish advisories, or for consumers, particularly given the difficulty of interpreting the ratios. PMID:22664537

  15. Interspecific and intraspecific variation in selenium:mercury molar ratios in saltwater fish from the Aleutians: potential protection on mercury toxicity by selenium.

    PubMed

    Burger, Joanna; Gochfeld, Michael; Jeitner, Christian; Donio, Mark; Pittfield, Taryn

    2012-08-01

    A number of factors affect the consumption risk from mercury in fish, including mercury levels, seasonal patterns of mercury concentrations, human consumption patterns, and sensitive populations (e.g. pregnant women, fetuses, young children, and yet unknown genetic factors). Recently the protective effects of selenium on methylmercury toxicity have been publicized, particularly for saltwater fish. We examine levels of mercury and selenium in several species of fish and seabirds from the Aleutians (Alaska), determine selenium:mercury molar ratios, and examine species-specific and individual variation in the ratios as a means of exploring the use of the ratio in risk assessment and risk management. Variation among species was similar for mercury and selenium. There was significant interspecific and intraspecific variation in selenium:mercury molar ratios for fish, and for birds. The mean selenium:mercury molar ratios for all fish and bird species were above 1, meaning there was an excess of selenium relative to mercury. It has been suggested that an excess of selenium confers some protective advantage for salt water fish, although the degree of excess necessary is unclear. The selenium:mercury molar ratio was significantly correlated negatively with total length for most fish species, but not for dolly varden. Some individuals of Pacific cod, yellow irish lord, rock greenling, Pacific halibut, dolly varden, and to a lesser extent, flathead sole, had selenium:mercury ratios below 1. No bird muscle had an excess of mercury (ratio below 1), and only glaucous-winged gull and pigeon guillemot had ratios between 1 and 5. There was a great deal of variation in selenium:mercury molar ratios within fish species, and within bird species, making it difficult and impractical to use these ratios in risk assessment or management, for fish advisories, or for consumers, particularly given the difficulty of interpreting the ratios.

  16. Selenium in mammalian spermiogenesis.

    PubMed

    Flohé, Leopold

    2007-10-01

    The role of selenium in male fertility is reviewed with special emphasis on selenoprotein P and phospholipid hydroperoxide glutathione peroxidase (GPx4) in spermiogenesis. Inverse genetics reveal that selenoprotein P is required for selenium supply to the testis. GPx4 is abundantly synthesized in spermatids. As a moonlighting protein it is transformed in the later stages of spermiogenesis from an active selenoperoxidase into a structural protein that becomes a constituent of the mitochondrial sheath of spermatozoa. The transformation is paralleled by loss of glutathione. Mechanistically, the process is an alternate substrate inactivation of GPx4 resulting from reactions of its selenenic form with thiols of GPx4 itself and other proteins. Circumstantial evidence and ongoing experimental genetics indicate that the mitochondrially expressed form of the GPx4 gene is the most relevant one in spermiogenesis, with the nuclear form being dispensable for fertility and the role of cytosolic GPx4 remaining unclear. Clinical data reveal a strong association of low sperm GPx4 with infertility. Thus, impaired GPx4 biosynthesis, due to selenium deficiency or to genetic defects in gpx4 itself or in proteins involved in Se distribution and selenoprotein biosynthesis, causes male infertility, but can also be an epiphenomenon due to any perturbation of testicular function.

  17. 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

  18. Selenium, Folate, and Colon Cancer

    PubMed Central

    Connelly-Frost, Alexandra; Poole, Charles; Satia, Jessie A.; Kupper, Lawrence L.; Millikan, Robert C.; Sandler, Robert S.

    2009-01-01

    Background Selenium is an essential trace element which has been implicated in cancer risk; however, study results have been inconsistent with regard to colon cancer. Our objectives were to 1) investigate the association between selenium and colon cancer 2) evaluate possible effect measure modifiers and 3) evaluate potential biases associated with the use of post-diagnostic serum selenium measures Methods The North Carolina Colon Cancer Study is a large population-based, case-control study of colon cancer in North Carolina between 1996 and 2000 (n=1,691). Nurses interviewed patients about diet and lifestyle and drew blood specimens which were used to measure serum selenium. Results Individuals who had both high serum selenium (>140 mcg/L) and high reported folate (>354 mcg/day), had a reduced relative risk of colon cancer (OR=0.5, 95% CI=0.4,0.8). The risk of colon cancer for those with high selenium and low folate was approximately equal to the risk among those with low selenium and low folate (OR=1.1, 95% CI=0.7,1.5) as was the risk for those with low selenium and high folate (OR=0.9, 95% CI=0.7–1.2). We did not find evidence of bias due to weight loss, stage at diagnosis, or time from diagnosis to selenium measurement. Conclusion High levels of serum selenium and reported folate jointly were associated with a substantially reduced risk of colon cancer. Folate status should be taken into account when evaluating the relation between selenium and colon cancer in future studies. Importantly, weight loss, stage at diagnosis, or time from diagnosis to blood draw did not appear to produce strong bias in our study. PMID:19235033

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

    PubMed

    Burger, Joanna; Jeitner, Christian; Donio, Mark; Pittfield, Taryn; Gochfeld, Michael

    2013-01-15

    A number of contaminants affect fish health, including mercury and selenium, and the selenium:mercury molar ratio. Recently the protective effects of selenium on methylmercury toxicity have been publicized, particularly for consumption of saltwater fish. Yet the relative ameliorating effects of selenium on toxicity within fish have not been examined, nor has the molar ratio in different tissues, (i.e. brain). We examined mercury and selenium levels in brain, kidney, liver, red and white muscle, and skin and scales in bluefish (Pomatomus saltatrix) (n=40) from New Jersey to determine whether there were toxic levels of either metal, and we computed the selenium:mercury molar ratios by tissues. Total mercury averaged 0.32±0.02 ppm wet weight in edible muscle and 0.09±0.01 ppm in brain. Selenium concentration averaged 0.37±0.03 in muscle and 0.36±0.03 ppm in brain. There were significant differences in levels of mercury, selenium, and selenium:mercury molar ratios, among tissues. Mercury and selenium levels were correlated in kidney and skin/scales. Mercury levels were highest in kidney, intermediate in muscle and liver, and lowest in brain and skin/scales; selenium levels were also highest in kidney, intermediate in liver, and were an order of magnitude lower in the white muscle and brain. Mercury levels in muscle, kidney and skin/scales were positively correlated with fish size (length). Selenium levels in muscle, kidney and liver were positively correlated with fish length, but in brain; selenium levels were negatively correlated with fish length. The selenium:mercury molar ratio was negatively correlated with fish length for white muscle, liver, kidney, and brain, particularly for fish over 50 cm in length, suggesting that older fish experience less protective advantages of selenium against mercury toxicity than smaller fish, and that consumers of bluefish similarly receive less advantage from eating larger fish. Copyright © 2012 Elsevier B.V. All rights

  20. Selenium dynamics in Farmington Bay wetlands, Great Salt Lake, Salt Lake City, Utah, USA.

    NASA Astrophysics Data System (ADS)

    Dicataldo, G.; Hayes, D. F.; Miller, T. G.; Chaudhuri, S.

    2006-12-01

    The dynamics of Selenium (Se) and other water quality parameters in the Farmington Bay wetlands were presented. This is the first time that the fate and transport of selenium is being studied in Farmington Bay wetlands. The significant salinity gradient between wetland impoundments and the hypersaline condition of the Great Salt Lake (GSL) make these wetlands systems unique. Selenium has been observed for the first time to cycle diurnally. A 100% increase of total selenium was measured during a 24-hour study in October 2005 at site #5320 at nighttime (i.e., 1.99 micrograms/L at 3:00 a.m. MST) compared to daytime (i.e., 0.99 micrograms/L at 2:00 p.m. MST). Particulate selenium also increased at the same site during nighttime and decreased during daylight. No significant daily changes were measured in dissolved selenium concentrations between day and night. Total suspended solids (TSS) measured during the same time period increased to a maximum concentration of 107 mg/L (at 4:21 a.m. MST) during nighttime and dramatically decreased after sunrise (i.e., 18.8 mg/L at 8:21 a.m. MST). Particulate generation at night could be linked to total and particulate selenium increase during this time period. Later studies in May 2006 have shown that total organic carbon (TOC) increased about 3.5-folds (i.e., from 2.9 mg/L to 12.9 mg/L) during nighttime (with high peak at 4:00 a.m. MST) and decreased dramatically at sunrise (about 6:30 a.m. MST) in May 2006. Seasonal selenium speciation showed for the first time that the predominant species reaching the Farmington Bay are elemental selenium and selenide species (organic and inorganic) (Se(0) + Se(-2)). This is a significant finding toward a better understand of the bioavailability of selenium to birds and aquatic life in Farmington Bay. The selenium concentration as water parcels moved through the system showed to be reduced up to 186%. Also, average monthly loads of selenium to Farmington Bay from Ambassador Duck Club wetlands

  1. Measuring bioavailable copper using anodic stripping voltammetry

    SciTech Connect

    Deaver, E.; Rodgers, J.H. Jr.

    1996-11-01

    Since speciation can affect bioavailability and toxicity of copper in aquatic systems, accurate predictions of effects of bioavailable forms require detection and/or measurement of these forms. To develop an approach for measurement of bioavailable copper, a copper sulfate solution was used in 10-d aqueous and sediment toxicity tests with Hyalella azteca Saussure. These tests encompassed ranges of pH, alkalinity, hardness, and conductivity. Changes in copper speciation were measured using atomic absorption spectroscopy (AA) for dissolved copper and differential pulse anodic stripping voltammetry (DPASV) for labile copper, and concentrations were evaluated relative to amphipod survival. Ten-day LC50s based on AA-measured aqueous copper concentrations ranged from 42 to 142 {micro}g Cu/L, and LC50s based on DPASV-measured copper concentrations ranged from 17.4 to 24.8 {micro}g Cu/L. In 10-d tests using copper-amended sediments with diverse characteristics and AA-measured copper concentrations spanning an order of magnitude, total copper concentrations were not predictive of sediment toxicity, but H. azteca survival was explained by DPASV measurements that varied by {le}4%. In order to make defensible estimates of the potential risk of metals in sediments or water, it is essential to identify the fraction of total metal that is bioavailable. In these experiments, DPASV was useful for measuring bioavailable copper in aqueous and sediment tests with H. azteca.

  2. Arsenic Bioavailability, Bioaccessibility, And Speciation

    EPA Science Inventory

    The term bioavailability has many different meanings across various disciplines. Often bioavailability is concerned with human health aspects such as the case of urban children interacting with contaminated soil. The still utilized approach to base risk assessment on total meta...

  3. Arsenic Bioavailability, Bioaccessibility, And Speciation

    EPA Science Inventory

    The term bioavailability has many different meanings across various disciplines. Often bioavailability is concerned with human health aspects such as the case of urban children interacting with contaminated soil. The still utilized approach to base risk assessment on total meta...

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

    PubMed

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

    2016-01-01

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

  5. Selenium accumulation in lettuce germplasm

    USDA-ARS?s Scientific Manuscript database

    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...

  6. BIOAVAILABILITY: SCIENCE AND ACCEPTANCE

    EPA Science Inventory

    Reducing risk from elevated levels of soil Pb involves removal, covering, or dilution by mixing with uncontaminated soil. Understanding that soil lead bioavailability is related to metal speciation and that in situ remediation techniques can alter metal speciation EPA's Na...

  7. Thermodynamically Correct Bioavailability Estimations

    DTIC Science & Technology

    1992-04-30

    6448 I 1. SWPPUMENTA* NOTIS lIa. OISTUAMJTiOAVAILAIILTY STATIMENT 121 OT REbT ostwosCo z I Approved for public release; distribution unlimited... research is to develop thermodynamically correct bioavailability estimations using chromatographic stationary phases as a model of the "interphase

  8. Modeling food web structure and selenium biomagnification in Lake Macquarie, New South Wales, Australia, using stable carbon and nitrogen isotopes.

    PubMed

    Schneider, Larissa; Maher, William A; Potts, Jaimie; Taylor, Anne M; Batley, Graeme E; Krikowa, Frank; Chariton, Anthony A; Gruber, Bernd

    2015-03-01

    As a consequence of coal-fired power station operations, elevated selenium concentrations have been reported in the sediments and biota of Lake Macquarie (New South Wales, Australia). In the present study, an ecosystem-scale model has been applied to determine how selenium in a seagrass food web is processed from sediments and water through diet to predators, using stable isotopes (δ(13) C and δ(15) N) to establish the trophic position of organisms. Trophic position, habitat, and feeding zone were examined as possible factors influencing selenium bioaccumulation. Selenium concentrations ranged from 0.2 μg/g dry weight in macroalgae species to 12.9 μg/g in the carnivorous fish Gerres subfasciatus. A mean magnification factor of 1.39 per trophic level showed that selenium is biomagnifying in the seagrass food web. Habitat and feeding zone influenced selenium concentrations in invertebrates, whereas feeding zone was the only significant factor influencing selenium concentrations in fish. The sediment-water partitioning coefficient (Kd ) of 4180 showed that partitioning of selenium entering the lake to particulate organic material (POM) is occurring, and consequently availability to food webs from POM is high. Trophic transfer factors (invertebrate = 1.9; fish = 1.2) were similar to those reported for other water bodies, showing that input source is not the main determinant of the magnitude of selenium bioaccumulation in a food web, but rather the initial partitioning of selenium into bioavailable POM. Environ Toxicol Chem 2015;34:608-617. © 2014 SETAC.

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

    PubMed

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

    2008-09-29

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

  10. A Novel Organic Selenium Compound Exerts Unique Regulation of Selenium Speciation, Selenogenome, and Selenoproteins in Broiler Chicks.

    PubMed

    Zhao, Ling; Sun, Lv-Hui; Huang, Jia-Qiang; Briens, Mickael; Qi, De-Sheng; Xu, Shi-Wen; Lei, Xin Gen

    2017-05-01

    Background: A new organic selenium compound, 2-hydroxy-4-methylselenobutanoic acid (SeO), displayed a greater bioavailability than sodium selenite (SeNa) or seleno-yeast (SeY) in several species.Objective: This study sought to determine the regulation of the speciation of selenium, expression of selenogenome and selenocysteine biosynthesis and degradation-related genes, and production of selenoproteins by the 3 forms of selenium in the tissues of broiler chicks.Methods: Day-old male chicks (n = 6 cages/diet, 6 chicks/cage) were fed a selenium-deficient, corn and soy-based diet [base diet (BD), 0.05 mg Se/kg] or the BD + SeNa, SeY, or SeO at 0.2 mg Se/kg for 6 wk. Plasma, livers, and pectoral and thigh muscles were collected at weeks 3 and 6 to assay for total selenium, selenomethionine, selenocysteine, redox status, and selected genes, proteins, and enzymes.Results: Although both SeY and SeO produced greater concentrations (P < 0.05) of total selenium (20-172%) and of selenomethionine (≤15-fold) in the liver, pectoral muscle, and thigh than those of SeNa, SeO further raised (P < 0.05) these concentrations by 13-37% and 43-87%, respectively, compared with SeY. Compared with the BD, only SeO enhanced (P < 0.05) the mRNA of selenoprotein (Seleno) s and methionine sulfoxide reductase B1 (Msrb1) in the liver and thigh (62-98%) and thioredoxin reductase (TXRND) activity in the pectoral and thigh muscles (20-37%) at week 3. Furthermore, SeO increased (P < 0.05) the expression of glutathione peroxidase (Gpx) 3, GPX4, SELENOP, and SELENOU relative to the SeNa group by 26-207%, and the expression of Selenop, O-phosphoseryl-transfer RNA (tRNA):selenocysteinyl-tRNA synthase, GPX4, and SELENOP relative to the SeY group by 23-55% in various tissues.Conclusions: Compared with SeNa or SeY, SeO demonstrated a unique ability to enrich selenomethionine and total selenium depositions, to induce the early expression of Selenos and Mrsb1 mRNA and TXRND activity, and to enhance the

  11. Selenium accumulation and metabolism in algae.

    PubMed

    Schiavon, Michela; Ertani, Andrea; Parrasia, Sofia; Vecchia, Francesca Dalla

    2017-08-01

    Selenium (Se) is an intriguing element because it is metabolically required by a variety of organisms, but it may induce toxicity at high doses. Algae primarily absorb selenium in the form of selenate or selenite using mechanisms similar to those reported in plants. However, while Se is needed by several species of microalgae, the essentiality of this element for plants has not been established yet. The study of Se uptake and accumulation strategies in micro- and macro-algae is of pivotal importance, as they represent potential vectors for Se movement in aquatic environments and Se at high levels may affect their growth causing a reduction in primary production. Some microalgae exhibit the capacity of efficiently converting Se to less harmful volatile compounds as a strategy to cope with Se toxicity. Therefore, they play a crucial role in Se-cycling through the ecosystem. On the other side, micro- or macro-algae enriched in Se may be used in Se biofortification programs aimed to improve Se content in human diet via supplementation of valuable food. Indeed, some organic forms of selenium (selenomethionine and methylselenocysteine) are known to act as anticarcinogenic compounds and exert a broad spectrum of beneficial effects in humans and other mammals. Here, we want to give an overview of the developments in the current understanding of Se uptake, accumulation and metabolism in algae, discussing potential ecotoxicological implications and nutritional aspects. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Nanosized Selenium: A Novel Platform Technology to Prevent Bacterial Infections

    NASA Astrophysics Data System (ADS)

    Wang, Qi

    As an important category of bacterial infections, healthcare-associated infections (HAIs) are considered an increasing threat to the safety and health of patients worldwide. HAIs lead to extended hospital stays, contribute to increased medical costs, and are a significant cause of morbidity and mortality. In the United States, infections encountered in the hospital or a health care facility affect more than 1.7 million patients, cost 35.7 billion to 45 billion, and contribute to 88,000 deaths in hospitals annually. The most conventional and widely accepted method to fight against bacterial infections is using antibiotics. However, because of the widespread and sometimes inappropriate use of antibiotics, many strains of bacteria have rapidly developed antibiotic resistance. Those new, stronger bacteria pose serious, worldwide threats to public health and welfare. In 2014, the World Health Organization (WHO) reported antibiotic resistance as a global serious threat that is no longer a prediction for the future but is now reality. It has the potential to affect anyone, of any age, in any country. The most effective strategy to prevent antibiotic resistance is minimizing the use of antibiotics. In recent years, nanomaterials have been investigated as one of the potential substitutes of antibiotics. As a result of their vastly increased ratio of surface area to volume, nanomaterials will likely exert a stronger interaction with bacteria which may affect bacterial growth and propagation. A major concern of most existing antibacterial nanomaterials, like silver nanoparticles, is their potential toxicity. But selenium is a non-metallic material and a required nutrition for the human body, which is recommended by the FDA at a 53 to 60 μg daily intake. Nanosized selenium is considered to be healthier and less toxic compared with many metal-based nanomaterials due to the generation of reactive oxygen species from metals, especially heavy metals. Therefore, the objectives of

  13. Cytotoxicity and therapeutic effect of irinotecan combined with selenium nanoparticles.

    PubMed

    Gao, Fuping; Yuan, Qing; Gao, Liang; Cai, Pengju; Zhu, Huarui; Liu, Ru; Wang, Yaling; Wei, Yueteng; Huang, Guodong; Liang, Jian; Gao, Xueyun

    2014-10-01

    Although chemotherapeutic drugs are widely applied for clinic tumor treatment, severe toxicity restricts their therapeutic efficacy. In this study, we reported a new form of selenium, selenium nanoparticles (Nano Se) which have significant lower toxicity and acceptable bioavailability. We investigated Nano Se as chemotherapy preventive agent to protect against toxicities of anticancer drug irinotecan and synergistically enhance the anti-tumor treatment effect in vitro and in vivo. The underlying mechanisms were also investigated. The combination of Nano Se and irinotecan showed increased cytotoxic effect with HCT-8 tumor cells likely by p53 mediated apoptosis. Nano Se inhibited growth of HCT-8 tumor cells partially through caspases mediated apoptosis. In vivo experiment showed Nano Se at a dose of 4 mg/kg/day significantly alleviated adverse effects induced by irinotecan (60 mg/kg) treatment. Nano Se alone treatment did not induce any toxic manifestations. The combination of Nano Se and irinotecan dramatically inhibited tumor growth and significantly induced apoptosis of tumor cells in HCT-8 cells xenografted tumor. Tumor inhibition rate was about 17.2%, 48.6% and 62.1% for Nano Se, irinotecan and the combination of Nano Se and irinotecan, respectively. The beneficial effects of Nano Se for tumor therapy were mainly ascribed to selectively regulating Nrf2-ARE (antioxidant responsive elements) pathway in tumor tissues and normal tissues. Our results suggest Nano Se is a promising selenium species with potential application in cancer treatment.

  14. Four selenoproteins, protein biosynthesis, and Wnt signalling are particularly sensitive to limited selenium intake in mouse colon.

    PubMed

    Kipp, Anna; Banning, Antje; van Schothorst, Evert M; Méplan, Catherine; Schomburg, Lutz; Evelo, Chris; Coort, Susan; Gaj, Stan; Keijer, Jaap; Hesketh, John; Brigelius-Flohé, Regina

    2009-12-01

    Selenium is an essential micronutrient. Its recommended daily allowance is not attained by a significant proportion of the population in many countries and its intake has been suggested to affect colorectal carcinogenesis. Therefore, microarrays were used to determine how both selenoprotein and global gene expression patterns in the mouse colon were affected by marginal selenium deficiency comparable to variations in human dietary intakes. Two groups of 12 mice each were fed a selenium-deficient (0.086 mg Se/kg) or a selenium-adequate (0.15 mg Se/kg) diet. After 6 wk, plasma selenium level, liver, and colon glutathione peroxidase (GPx) activity in the deficient group was 12, 34, and 50%, respectively, of that of the adequate group. Differential gene expression was analysed with mouse 44K whole genome microarrays. Pathway analysis by GenMAPP identified the protein biosynthesis pathway as most significantly affected, followed by inflammation, Delta-Notch and Wnt pathways. Selected gene expression changes were confirmed by quantitative real-time PCR. GPx1 and the selenoproteins W, H, and M, responded significantly to selenium intake making them candidates as biomarkers for selenium status. Thus, feeding a marginal selenium-deficient diet resulted in distinct changes in global gene expression in the mouse colon. Modulation of cancer-related pathways may contribute to the higher susceptibility to colon carcinogenesis in low selenium status.

  15. The effect of selenium on reproduction of black-tailed deer (Odocoileus hemionus columbianus) in Shasta County California

    SciTech Connect

    Flueck, W.T.

    1989-01-01

    This study was to determine if nutritional inadequacy of selenium may be responsible for a declining reproductive rate of a migratory herd of black-tailed deer. Selenium is an essential trace mineral for mammalian herbivores. Deficiency affects primarily neonates resulting in increased mortality rates. Shasta County, California is indigenously low in selenium due to soil characteristics. Local livestock enterprises have experienced reproductive problems, which were responsive to selenium treatment. The low recruitment rate in the deer herd suggested a physiological link between low selenium status and reproductive problems, and an experimental trial was initiated. Free ranging adult females were supplemented with selenium rumen pellets and marked with radio transmitters. From 1985 to 1987, the selenium dose was doubled as compared to 1984. It was established that evaluation of selenium status by determining whole blood selenium levels adequately describes the major bioactive form of selenium, glutathione peroxidase. To evaluate the experimental trial, the pre-weaning survival rate of progeny of supplemented females was compared with the rate in the untreated herd.

  16. Relative Bioavailability and Bioaccessibility and Speciation of Arsenic in Contaminated Soils

    PubMed Central

    Scheckel, Kirk G.; Nelson, Clay M.; Seales, Paul E.; Lee, Grace E.; Hughes, Michael F.; Miller, Bradley W.; Yeow, Aaron; Gilmore, Thomas; Serda, Sophia M.; Harper, Sharon; Thomas, David J.

    2011-01-01

    Background: Assessment of soil arsenic (As) bioavailability may profoundly affect the extent of remediation required at contaminated sites by improving human exposure estimates. Because small adjustments in soil As bioavailability estimates can significantly alter risk assessments and remediation goals, convenient, rapid, reliable, and inexpensive tools are needed to determine soil As bioavailability. Objectives: We evaluated inexpensive methods for assessing As bioavailability in soil as a means to improve human exposure estimates and potentially reduce remediation costs. Methods: Nine soils from residential sites affected by mining or smelting activity and two National Institute of Standards and Technology standard reference materials were evaluated for As bioavailability, bioaccessibility, and speciation. Arsenic bioavailability was determined using an in vivo mouse model, and As bioaccessibility was determined using the Solubility/Bioavailability Research Consortium in vitro assay. Arsenic speciation in soil and selected soil physicochemical properties were also evaluated to determine whether these parameters could be used as predictors of As bioavailability and bioaccessibility. Results: In the mouse assay, we compared bioavailabilities of As in soils with that for sodium arsenate. Relative bioavailabilities (RBAs) of soil As ranged from 11% to 53% (mean, 33%). In vitro soil As bioaccessibility values were strongly correlated with soil As RBAs (R2 = 0.92). Among physicochemical properties, combined concentrations of iron and aluminum accounted for 80% and 62% of the variability in estimates of RBA and bioaccessibility, respectively. Conclusion: The multifaceted approach described here yielded congruent estimates of As bioavailability and evidence of interrelations among physicochemical properties and bioavailability estimates. PMID:21749965

  17. Relative bioavailability and bioaccessibility and speciation of arsenic in contaminated soils.

    PubMed

    Bradham, Karen D; Scheckel, Kirk G; Nelson, Clay M; Seales, Paul E; Lee, Grace E; Hughes, Michael F; Miller, Bradley W; Yeow, Aaron; Gilmore, Thomas; Serda, Sophia M; Harper, Sharon; Thomas, David J

    2011-11-01

    Assessment of soil arsenic (As) bioavailability may profoundly affect the extent of remediation required at contaminated sites by improving human exposure estimates. Because small adjustments in soil As bioavailability estimates can significantly alter risk assessments and remediation goals, convenient, rapid, reliable, and inexpensive tools are needed to determine soil As bioavailability. We evaluated inexpensive methods for assessing As bioavailability in soil as a means to improve human exposure estimates and potentially reduce remediation costs. Nine soils from residential sites affected by mining or smelting activity and two National Institute of Standards and Technology standard reference materials were evaluated for As bioavailability, bioaccessibility, and speciation. Arsenic bioavailability was determined using an in vivo mouse model, and As bioaccessibility was determined using the Solubility/Bioavailability Research Consortium in vitro assay. Arsenic speciation in soil and selected soil physicochemical properties were also evaluated to determine whether these parameters could be used as predictors of As bioavailability and bioaccessibility. In the mouse assay, we compared bioavailabilities of As in soils with that for sodium arsenate. Relative bioavailabilities (RBAs) of soil As ranged from 11% to 53% (mean, 33%). In vitro soil As bioaccessibility values were strongly correlated with soil As RBAs (R² = 0.92). Among physicochemical properties, combined concentrations of iron and aluminum accounted for 80% and 62% of the variability in estimates of RBA and bioaccessibility, respectively. The multifaceted approach described here yielded congruent estimates of As bioavailability and evidence of interrelations among physicochemical properties and bioavailability estimates.

  18. Contamination of different portions of raw and boiled specimens of Norway lobster by mercury and selenium.

    PubMed

    Perugini, Monia; Visciano, Pierina; Manera, Maurizio; Abete, Maria Cesarina; Gavinelli, Stefania; Amorena, Michele

    2013-11-01

    The aim of this study was to evaluate mercury and selenium distribution in different portions (exoskeleton, white meat and brown meat) of Norway lobster (Nephrops norvegicus). Some samples were also analysed as whole specimens. The same portions were also examined after boiling, in order to observe if this cooking practice could affect mercury and selenium concentrations. The highest mercury concentrations were detected in white meat, exceeding in all cases the maximum levels established by European legislation. The brown meat reported the highest selenium concentrations. In all boiled samples, mercury levels showed a statistically significant increase compared to raw portions. On the contrary, selenium concentrations detected in boiled samples of white meat, brown meat and whole specimen showed a statistically significant decrease compared to the corresponding raw samples. These results indicate that boiling modifies mercury and selenium concentrations. The high mercury levels detected represent a possible risk for consumers, and the publication and diffusion of specific advisories concerning seafood consumption is recommended.

  19. Mycochemical Changes Induced by Selenium Enrichment in P. ostreatus Fruiting Bodies.

    PubMed

    Carrasco-Gonzalez, Jorge A; Serna-Saldívar, Sergio O; Gutierrez-Uribe, Janet A

    2017-05-24

    The effects of selenium enrichment on the biological efficiency, phenolic compounds, amino acid profile, antioxidant capacity, and cellular antioxidant activity (CAA) were evaluated in Pleurotus ostreatus fruiting bodies (FB) harvested during three sequential flushes. Sodium selenate was used to reach selenium content of 17.5 or 5.8 mg/kg in the sorghum straw substrate. Biological efficiency and total selenium content increased. One of the main differences among treatments was in ergothioneine content, an indicator of oxidative stress that was positively related with valine and isoleucine contents and negatively related to leucine and phenylalanine. Besides ergothioneine, nucleosides derived from adenine and uracyl were the major peaks observed in all treatments, and coumaric and ferulic acids were found in the bound phenolics extract. Selenium enrichment also affected the antioxidant capacity, and particularly the methanolic extract obtained from the second flush of FB cultivated in selenium-enriched substrate (17.5 mg/kg) had the best CAA.

  20. Selenium incorporation using recombinant techniques

    PubMed Central

    Walden, Helen

    2010-01-01

    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. PMID:20382987

  1. Regulation of Selenium Metabolism and Transport.

    PubMed

    Burk, Raymond F; Hill, Kristina E

    2015-01-01

    Selenium is regulated in the body to maintain vital selenoproteins and to avoid toxicity. When selenium is limiting, cells utilize it to synthesize the selenoproteins most important to them, creating a selenoprotein hierarchy in the cell. The liver is the central organ for selenium regulation and produces excretory selenium forms to regulate whole-body selenium. It responds to selenium deficiency by curtailing excretion and secreting selenoprotein P (Sepp1) into the plasma at the expense of its intracellular selenoproteins. Plasma Sepp1 is distributed to tissues in relation to their expression of the Sepp1 receptor apolipoprotein E receptor-2, creating a tissue selenium hierarchy. N-terminal Sepp1 forms are taken up in the renal proximal tubule by another receptor, megalin. Thus, the regulated whole-body pool of selenium is shifted to needy cells and then to vital selenoproteins in them to supply selenium where it is needed, creating a whole-body selenoprotein hierarchy.

  2. 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

  3. Epigenetic effects of selenium and their implications for health.

    PubMed

    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.

  4. Selenium speciation in the Fountain Creek Watershed and its effects on fish diversity.

    PubMed

    Carsella, James; Melnykov, Igor; Bonetti, Sandra; Sánchez-Lombardo, Irma; Crans, Debbie C

    2017-07-01

    Se is an environmental concern as it can be toxic if present in high concentrations even though it is a dietary requirement for all animals. Se levels are a special concern in the Fountain Creek Watershed located in southeastern Colorado whose geological source is the Se-rich Pierre Shale. Segments of Fountain Creek have Se water levels that exceed the current EPA limit of 5 µg/l. In the studies described here, the effects of river water containing selenium were examined on fish populations at different sites along the Fountain Creek Watershed. Based on the hypothesis that high levels of Se present in the Creek and resident bryophytes should be an indicator of diversity in the river fish we explored the possibility that the low toxicity of the selenium could be due to speciation. A speciation analysis was conducted to determine the selenium(IV) and selenium(VI). Our results show that sites with higher ratios of the more toxic Se(IV) relative to total selenium exhibit lower fish diversity and number of fish. Our results indicate that factors, other than total Se, such as Se speciation may be involved in controlling the bioavailability and toxicity of this element to aquatic organisms in Fountain Creek.

  5. [Selenium correction of male subfertility].

    PubMed

    Nikolaev, A A; Lutskiĭ, D L; Lozhkina, L V; Bochanovskiĭ, V A; Goncharova, L A

    1999-01-01

    To study the effect of selenium in subfertile men, three groups of men were studied. Group 1--31 subfertile men living in healthy environment, group 2--25 subfertile men exposed for a long time to low doses of gas containing hydrogen sulfide, group 3--control 43 fertile men. Men of groups 1 and 2 received 3 courses of selenium (3.5 microg/kg/day for 30 days). Before the treatment and after each course ejaculate fertility was assessed by spermogram, enzyme activity of alpha-amylase (EC 3.2.1.1) and lactate dehydrogenase (EC 1.1.1.27), concentrations of prostatic acid phosphatase, sperm-specific inhibitor tripsin and prostate-specific antigen. Selenium proved effective, the response being higher in group 2 than in group 1. The causes of this difference are discussed. It is thought possible to use selenium for correction of some subfertility forms in men.

  6. 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.

  7. Factors influencing micronutrient bioavailability in biofortified crops.

    PubMed

    Bechoff, Aurélie; Dhuique-Mayer, Claudie

    2017-02-01

    Dietary and human factors have been found to be the major factors influencing the bioavailability of micronutrients, such as provitamin A carotenoid (pVAC), iron, and zinc, in biofortified crops. Dietary factors are related to food matrix structure and composition. Processing can improve pVAC bioavailability by disrupting the food matrix but can also result in carotenoid losses. By degrading antinutrients, such as phytate, processing can also enhance mineral bioavailability. In in vivo interventions, biofortified crops have been shown to be overall efficacious in reducing micronutrient deficiency, with bioconversion factors varying between 2.3:1 and 10.4:1 for trans-β-carotene and amounts of iron and zinc absorbed varying between 0.7 and 1.1 mg/day and 1.1 and 2.1 mg/day, respectively. Micronutrient bioavailability was dependent on the crop type and the presence of fat for pVACs and on antinutrients for minerals. In addition to dietary factors, human factors, such as inflammation and disease, can affect micronutrient status. Understanding the interactions between micronutrients is also essential, for example, the synergic effect of iron and pVACs or the competitive effect of iron and zinc. Future efficacy trials should consider human status and genetic polymorphisms linked to interindividual variations.

  8. Sludge organics bioavailability

    SciTech Connect

    Eiceman, G.E.; Bellin, C.A.; Ryan, J.A.; O'Connor, G.A.

    1991-01-01

    Concern over the bioavailability of toxic organics that can occur in municipal sludges threatens routine land application of sludge. Available data, however, show that concentrations of priority organics in normal sludges are low. Sludges applied at agronomic rates yield chemical concentrations in soil-sludge mixtures 50 to 100 fold lower. Plant uptake at these pollutant concentrations (and at much higher concentrations) is minimal. Chemicals are either (1) accumulated at extremely low levels (PCBs), (2) possibly accumulated, but then rapidly metabolized within plants to extremely low levels (DEHP), or (3) likely degraded so rapidly in soil that only minor contamination occurs (PCP and 2,4-DNP).

  9. Bioavailability of bioactive food compounds: a challenging journey to bioefficacy.

    PubMed

    Rein, Maarit J; Renouf, Mathieu; Cruz-Hernandez, Cristina; Actis-Goretta, Lucas; Thakkar, Sagar K; da Silva Pinto, Marcia

    2013-03-01

    Bioavailability is a key step in ensuring bioefficacy of bioactive food compounds or oral drugs. Bioavailability is a complex process involving several different stages: liberation, absorption, distribution, metabolism and elimination phases (LADME). Bioactive food compounds, whether derived from various plant or animal sources, need to be bioavailable in order to exert any beneficial effects. Through a better understanding of the digestive fate of bioactive food compounds we can impact the promotion of health and improvement of performance. Many varying factors affect bioavailability, such as bioaccessibility, food matrix effect, transporters, molecular structures and metabolizing enzymes. Bioefficacy may be improved through enhanced bioavailability. Therefore, several technologies have been developed to improve the bioavailability of xenobiotics, including structural modifications, nanotechnology and colloidal systems. Due to the complex nature of food bioactive compounds and also to the different mechanisms of absorption of hydrophilic and lipophilic bioactive compounds, unravelling the bioavailability of food constituents is challenging. Among the food sources discussed during this review, coffee, tea, citrus fruit and fish oil were included as sources of food bioactive compounds (e.g. (poly)phenols and polyunsaturated fatty acids (PUFAs)) since they are examples of important ingredients for the food industry. Although there are many studies reporting on bioavailability and bioefficacy of these bioactive food components, understanding their interactions, metabolism and mechanism of action still requires extensive work. This review focuses on some of the major factors affecting the bioavailability of the aforementioned bioactive food compounds. © 2012 Nestec S. A.. British Journal of Clinical Pharmacology © 2012 The British Pharmacological Society.

  10. 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.

  11. 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.

  12. Selenium availability in Texas: possible clinical significance

    SciTech Connect

    Cech, I.; Holguin, A.; Sokolow, H.; Smith, V.

    1984-11-01

    In light of recent reports that have indicated that selenium is an essential micronutrient and possible natural cancer inhibitor, data on the geographic distributions of selenium in Texas were gathered and compared with the distribution of age-adjusted cancer mortality rates. We considered concentrations of selenium measured in ground and surface water to be indicators of its presence in rocks, soil, and locally grown crops. Texas water sources were found to be poor in selenium, except for the Panhandle and the West Texas regions, where soil consists of erosion products from the selenium-rich Rocky Mountains. In general, lower cancer mortality was observed for the selenium-rich regions of Texas compared with cancer mortality for the selenium poor regions. Even though the risks from cancer-provoking factors also differed geographically, the observed pattern was sufficiently suggestive to warrant further attention to selenium. 13 references, 4 figures, 2 tables.

  13. Selenium availability in Texas: possible clinical significance.

    PubMed

    Cech, I; Holguin, A; Sokolow, H; Smith, V

    1984-11-01

    In light of recent reports that have indicated that selenium is an essential micronutrient and possible natural cancer inhibitor, data on the geographic distributions of selenium in Texas were gathered and compared with the distribution of age-adjusted cancer mortality rates. We considered concentrations of selenium measured in ground and surface water to be indicators of its presence in rocks, soil, and locally grown crops. Texas water sources were found to be poor in selenium, except for the Panhandle and the West Texas regions, where soil consists of erosion products from the selenium-rich Rocky Mountains. In general, lower cancer mortality was observed for the selenium-rich regions of Texas compared with cancer mortality for the selenium-poor regions. Even though the risks from cancer-provoking factors also differed geographically, the observed pattern was sufficiently suggestive to warrant further attention to selenium.

  14. Baseline selenium status and effects of selenium and vitamin e supplementation on prostate cancer risk.

    PubMed

    Kristal, Alan R; Darke, Amy K; Morris, J Steven; Tangen, Catherine M; Goodman, Phyllis J; Thompson, Ian M; Meyskens, Frank L; Goodman, Gary E; Minasian, Lori M; Parnes, Howard L; Lippman, Scott M; Klein, Eric A

    2014-03-01

    The Selenium and Vitamin E Cancer Prevention Trial found no effect of selenium supplementation on prostate cancer (PCa) risk but a 17% increased risk from vitamin E supplementation. This case-cohort study investigates effects of selenium and vitamin E supplementation conditional upon baseline selenium status. There were 1739 total and 489 high-grade (Gleason 7-10) PCa cases and 3117 men in the randomly selected cohort. Proportional hazards models estimated hazard ratios (HRs) and 95% confidence intervals (CIs) for effects of supplementation within quintiles of baseline toenail selenium. Cox proportional hazards models were used to estimate hazard ratios, and all statistical tests are two-sided. Toenail selenium, in the absence of supplementation, was not associated with PCa risk. Selenium supplementation (combined selenium only and selenium + vitamin E arms) had no effect among men with low selenium status (<60th percentile of toenail selenium) but increased the risk of high-grade PCa among men with higher selenium status by 91% (P = .007). Vitamin E supplementation (alone) had no effect among men with high selenium status (≥40th percentile of toenail selenium) but increased the risks of total, low-grade, and high-grade PCa among men with lower selenium status (63%, P = .02; 46%, P = .09; 111%, P = .008, respectively). Selenium supplementation did not benefit men with low selenium status but increased the risk of high-grade PCa among men with high selenium status. Vitamin E increased the risk of PCa among men with low selenium status. Men should avoid selenium or vitamin E supplementation at doses that exceed recommended dietary intakes.

  15. Bioavailability of zinc, copper, and manganese from infant diets

    SciTech Connect

    Bell, J.G.

    1987-01-01

    A series of trace element absorption experiments were performed using the Sprague-Dawley suckling rat put and infant rhesis monkey (Macaca mulatta) with extrinsic radiolabeling to assess the bioavailability of Zn, Cu, and Mn from infant diets and to examine specific factors that affect absorption of these essential nutrients. Bioavailability of Cu as assessed by 6 h liver uptake (% of /sup 64/Cu dose) was highest from human milk and cow milk based formula and significantly lower from cow milk and soy based formula. Copper bioavailability from infant cereal products as assessed by whole body uptake (% of /sup 64/Cu dose) in d 20 rats, 9 h postintubation, was low compared to the bioavailability from cow milk or human milk alone. /sup 65/Zn uptake in d 20 rats, 9 h postintubation, was significantly lower from cereals fed alone or in combination with cow or human milk as compared to the uptake from the milks fed alone. Zn bioavailability varied among cereal diets, (lowest from cereals containing phytate and highest from cereal/fruit products). Mn bioavailability from infant diets was assessed using a modified suckling rat pup model. Bioavailability (24 h whole body retention of /sup 54/Mn) was high from all milks and commercial formulas tested.

  16. Selenium enrichment of table eggs.

    PubMed

    Bennett, D C; Cheng, K M

    2010-10-01

    Selenium is an essential trace element with a recommended dietary allowance for human adults of 55 μg/d. However, there is evidence that greater dietary intakes may have possible health benefits, including a reduction in the risk of cancer. Several studies have shown the feasibility of enriching eggs using organic Se and that Se-enriched eggs are an effective way to supplement human diets. However, few studies have examined the response of egg Se concentration to high (>1 μg/g) dietary organic Se intake by the laying hens. The objective of the current study is to examine the effect of higher dietary organic Se levels on production, egg mass, and egg Se levels. These were assessed by feeding 3 breeds of laying hens (Barred Plymouth Rock, Lohmann Brown, Lohmann White) a basal diet containing 0.3 μg of Se/g of diet as Na2SeO3. Into this diet, Se yeast (SelenoSource AF 600), an organic source of Se, was added at 1.0, 2.4, or 5.1 μg of Se/g of diet for 4 wk. Feed consumption, egg production, and egg mass were not affected by the dietary Se concentration in all 3 breeds. Within the range of Se levels employed in the laying hens' diet, egg Se content increased linearly as dietary levels of Se increased. The results of this study indicate that feeding up to 5.1 µg/g of Se will not affect egg production and the welfare of the laying hen and is a practical way of producing Se-enriched eggs for the consumers.

  17. [Selenium deficiency and infertility. Andrologic aspects].

    PubMed

    Szöllosi, János; Závaczki, Zoltán; Pál, Attila

    2008-09-14

    Absolute selenium deficiency in human is very rare, although suboptimal daily selenium intake may lead to an unrecognized relative deficiency. Among the many consequences ascribed to decreased selenium level, the effect on male fertility is summarised by the authors. Implications from biochemical, animal experimental and human research are discussed.

  18. Selenium deposition kinetics of different selenium sources in muscle and feathers of broilers.

    PubMed

    Couloigner, Florian; Jlali, Maamer; Briens, Mickael; Rouffineau, Friedrich; Geraert, Pierre-André; Mercier, Yves

    2015-11-01

    The objective of this study was to determine selenium (Se) deposition kinetics in muscles and feathers of broilers in order to develop a rapid method to compare bioavailability of selenium sources. Different Se sources such as 2-hydroxy-4-methylselenobutanoic acid (HMSeBA, SO), sodium selenite (SS) and seleno-yeast (SY) were compared for their kinetics on Se deposition in muscles and feathers in broiler chicks from 0 to 21 d of age. A total of 576 day-old broilers were divided into four treatments with 8 replicates of 18 birds per pen. The diets used in the experiment were a negative control (NC) not supplemented with Se and 3 diets supplemented with 0.2 mg Se/kg as SS, SY or SO. Total Se content in breast muscle and feathers were assessed on days 0, 7, 14 and 21. At 7 d of age, SO increased muscle Se content compared to D0 (P < 0.05), whereas with the other treatments, muscle Se concentration decreased (P < 0.05). After 21 days, organic Se sources maintained (SY) or increased (SO) (P < 0.05) breast muscle Se concentration compared to hatch value whereas inorganic source (SS) or non-supplemented group (NC) showed a significant decrease in tissue Se concentration (P < 0.05). At D21, Se contents of muscle and feathers were highly correlated (R(2) = 0.927; P < 0.0001). To conclude, these results indicate that efficiency of different Se sources can be discriminated through a 7 d using muscle Se content in broiler chickens. Muscle and feathers Se contents were highly correlated after 21 days. Also feather sampling at 21 days of age represents a reliable and non-invasive procedure for Se bioefficacy comparison.

  19. Effect of elemental nano-selenium on semen quality, glutathione peroxidase activity, and testis ultrastructure in male Boer goats.

    PubMed

    Shi, Li-guang; Yang, Ru-jie; Yue, Wen-bin; Xun, Wen-juan; Zhang, Chun-xiang; Ren, You-she; Shi, Lei; Lei, Fu-lin

    2010-04-01

    The objective of this experiment is to study the effects of novel elemental nano-selenium in the diet on testicular ultrastructure, semen quality and GSH-Px activity in male goats. Forty-two 2-month-old bucks were offered a total mixed ration which had been supplemented with nano-Se (0.3mg/kg Se) or unsupplemented (the control group only received 0.06mg/kg Se-background), for a period of 12 weeks (from weaning to sexual maturity). Results showed that the testicular Se level, semen glutathione peroxidase and ATPase activity increased significantly in the nano-Se supplementation group compared with control (P<0.05). The semen quality (volume, density, motility and pH) was not affected by added Se in diets, however, the sperm abnormality rate of control bucks was significantly higher than Se supplemented bucks (P<0.05). The testes of 5 goats in each group were examined by transmission electron microscopy (TEM), and showed that in Se-deficient bucks the membrane was damaged, and showed the occurrence of abnormalities in the mitochondria of the midpiece of spermatozoa. In conclusion, selenium deficiency resulted in abnormal spermatozoal mitochondria, and supplementation with nano-Se enhanced the testis Se content, testicular and semen GSH-Px activity, protected the membrane system integrity and the tight arrayment of the midpiece of the mitochondria. Further studies are required to research the novel elemental nano-Se with characterization of bioavailability and toxicity in small ruminants.

  20. Selenium accumulation by plants

    PubMed Central

    White, Philip J.

    2016-01-01

    Background Selenium (Se) is an essential mineral element for animals and humans, which they acquire largely from plants. The Se concentration in edible plants is determined by the Se phytoavailability in soils. Selenium is not an essential element for plants, but excessive Se can be toxic. Thus, soil Se phytoavailability determines the ecology of plants. Most plants cannot grow on seleniferous soils. Most plants that grow on seleniferous soils accumulate <100 mg Se kg–1 dry matter and cannot tolerate greater tissue Se concentrations. However, some plant species have evolved tolerance to Se, and commonly accumulate tissue Se concentrations >100 mg Se kg–1 dry matter. These plants are considered to be Se accumulators. Some species can even accumulate Se concentrations of 1000–15 000 mg Se kg–1 dry matter and are called Se hyperaccumulators. Scope This article provides an overview of Se uptake, translocation and metabolism in plants and highlights the possible genetic basis of differences in these between and within plant species. The review focuses initially on adaptations allowing plants to tolerate large Se concentrations in their tissues and the evolutionary origin of species that hyperaccumulate Se. It then describes the variation in tissue Se concentrations between and within angiosperm species and identifies genes encoding enzymes limiting the rates of incorporation of Se into organic compounds and chromosomal loci that might enable the development of crops with greater Se concentrations in their edible portions. Finally, it discusses transgenic approaches enabling plants to tolerate greater Se concentrations in the rhizosphere and in their tissues. Conclusions The trait of Se hyperaccumulation has evolved several times in separate angiosperm clades. The ability to tolerate large tissue Se concentrations is primarily related to the ability to divert Se away from the accumulation of selenocysteine and selenomethionine, which might be incorporated

  1. Selenium accumulation by plants.

    PubMed

    White, Philip J

    2016-02-01

    Selenium (Se) is an essential mineral element for animals and humans, which they acquire largely from plants. The Se concentration in edible plants is determined by the Se phytoavailability in soils. Selenium is not an essential element for plants, but excessive Se can be toxic. Thus, soil Se phytoavailability determines the ecology of plants. Most plants cannot grow on seleniferous soils. Most plants that grow on seleniferous soils accumulate <100 mg Se kg(-1) dry matter and cannot tolerate greater tissue Se concentrations. However, some plant species have evolved tolerance to Se, and commonly accumulate tissue Se concentrations >100 mg Se kg(-1) dry matter. These plants are considered to be Se accumulators. Some species can even accumulate Se concentrations of 1000-15 000 mg Se kg(-1 )dry matter and are called Se hyperaccumulators. This article provides an overview of Se uptake, translocation and metabolism in plants and highlights the possible genetic basis of differences in these between and within plant species. The review focuses initially on adaptations allowing plants to tolerate large Se concentrations in their tissues and the evolutionary origin of species that hyperaccumulate Se. It then describes the variation in tissue Se concentrations between and within angiosperm species and identifies genes encoding enzymes limiting the rates of incorporation of Se into organic compounds and chromosomal loci that might enable the development of crops with greater Se concentrations in their edible portions. Finally, it discusses transgenic approaches enabling plants to tolerate greater Se concentrations in the rhizosphere and in their tissues. The trait of Se hyperaccumulation has evolved several times in separate angiosperm clades. The ability to tolerate large tissue Se concentrations is primarily related to the ability to divert Se away from the accumulation of selenocysteine and selenomethionine, which might be incorporated into non-functional proteins

  2. Plants defective in calcium oxalate crystal formation have more bioavailable calcium

    USDA-ARS?s Scientific Manuscript database

    Bioavailable calcium affects bone formation and calcification. Here we investigate how a single gene mutation altering calcium partitioning in the forage crop Medicago truncatula affects calcium bioavailability. Previously, the cod5 Medicago mutant was identified which contains wild-type amounts o...

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

    PubMed Central

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

    2014-01-01

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

  4. GIS-assisted regression analysis to identify sources of selenium in streams

    USGS Publications Warehouse

    See, Randolph B.; Naftz, David L.; Qualls, Charles L.

    1992-01-01

    Using a geographic information system, a regression model has been developed to identify and to assess potential sources of selenium in the Kendrick Reclamation Project Area, Wyoming. A variety of spatially distributed factors was examined to determine which factors are most likely to affect selenium discharge in tributaries to the North Platte River. Areas of Upper Cretaceous Cody Shale and Quaternary alluvial deposits and irrigated land, length of irrigation canals, and boundaries of hydrologic subbasins of the major tributaries to the North Platte River were digitized and stored in a geographic information system. Selenium concentrations in samples of soil, plant material, ground water, and surface water were determined and evaluated. The location of all sampling sites was digitized and stored in the geographic information system, together with the selenium concentrations in samples. A regression model was developed using stepwise multiple regression of median selenium discharges on the physical and chemical characteristics of hydrologic subbasins. Results indicate that the intensity of irrigation in a hydrologic subbasin, as determined by area of irrigated land and length of irrigation delivery canals, accounts for the largest variation in median selenium discharges among subbasins. Tributaries draining hydrologic subbasins with greater intensity of irrigation result in greater selenium discharges to the North Platte River than do tributaries draining subbasins with lesser intensity of irrigation.

  5. Relative and combined effects of selenium, protein deficiency and ethanol on bone.

    PubMed

    González-Pérez, José María; González-Reimers, Emilio; Durán-Castellón, María del Carmen; Santolaria-Fernández, Franscisco; Galindo-Martín, Luis; RosVilamajó, Rosa; de la Vega-Prieto, María José; Viña-Rodríguez, Jose; Abreu-González, Pedro

    2011-04-01

    Some observations suggest that oxidative damage may affect both osteoblastic function and osteoclastic activity in alcohol-mediated bone alterations. Selenium, a potent antioxidant, is decreased in alcoholics. To analyse if the supplementation with selenium may alter bone changes observed in a murine model fed ethanol and/or a 2% protein-containing diet, following the Lieber-deCarli design. Adult male Sprague-Dawley rats were divided into 8 groups, which received the Lieber-DeCarli control diet, an isocaloric, 36% ethanol-containing diet, an isocaloric, 2% protein-containing diet; and an isocaloric diet containing 2% protein and 36% ethanol diet, and another similar four groups to which selenomethionine (1mg/kg body weight). After sacrifice (5 weeks later), trabecular bone mass was histomorphometrically assessed, bone and serum selenium were determined by flame atomic absorption spectrophotometry, and serum osteocalcin, insulin growth factor 1 (IGF-1), PTH and telopeptide, by radioimmunoanalysis. Liver glutathione peroxidase (GPX) activity was also determined. Ethanol-fed rats showed decreased TBM, IGF-1 and osteocalcin, especially when ethanol was added to a 2%-protein diet. Selenium did not modify at all bone parameters, despite a marked increase in serum selenium and a less pronounced one in bone selenium, and an increase in liver GPX. Our results do not support the existence of a beneficial effect of selenium addition on bone changes observed in this murine model treated following the Lieber-deCarli experimental design. Copyright © 2011 Elsevier GmbH. All rights reserved.

  6. Selenium and sulindac are synergistic to inhibit intestinal tumorigenesis in Apc/p21 mice.

    PubMed

    Bi, Xiuli; Pohl, Nicole; Dong, Huali; Yang, Wancai

    2013-01-17

    Both selenium and non-steroidal anti-inflammatory drug (NSAID) sulindac are effective in cancer prevention, but their effects are affected by several factors including epigenetic alterations and gene expression. The current study was designed to determine the effects of the combination of selenium and sulindac on tumor inhibition and the underlying mechanisms. We fed the intestinal tumor model Apc/p21 mice with selenium- and sulindac-supplemented diet for 24 weeks, and found that the combination of selenium and sulindac significantly inhibited intestinal tumorigenesis, in terms of reducing tumor incidence by 52% and tumor multiplicities by 80% (p<0.01). Mechanistic studies revealed that the combination of selenium and sulindac led to the significant induction of the expression of p27 and p53 and JNK1 phosphorylation, and led to the suppression of β-catenin and its downstream targets. Impressively, the data also showed that demythelation on p21 promoter was associated with tumor inhibition by the combination of selenium and sulindac. The selenium is synergistic with sulindac to exert maximal effects on tumor inhibition. This finding provides an important chemopreventive strategy using combination of anti-cancer agents, which has a great impact on cancer prevention and has a promising translational potential.

  7. Selenium and sulindac are synergistic to inhibit intestinal tumorigenesis in Apc/p21 mice

    PubMed Central

    2013-01-01

    Background Both selenium and non-steroidal anti-inflammatory drug (NSAID) sulindac are effective in cancer prevention, but their effects are affected by several factors including epigenetic alterations and gene expression. The current study was designed to determine the effects of the combination of selenium and sulindac on tumor inhibition and the underlying mechanisms. Results We fed the intestinal tumor model Apc/p21 mice with selenium- and sulindac-supplemented diet for 24 weeks, and found that the combination of selenium and sulindac significantly inhibited intestinal tumorigenesis, in terms of reducing tumor incidence by 52% and tumor multiplicities by 80% (p<0.01). Mechanistic studies revealed that the combination of selenium and sulindac led to the significant induction of the expression of p27 and p53 and JNK1 phosphorylation, and led to the suppression of β-catenin and its downstream targets. Impressively, the data also showed that demythelation on p21 promoter was associated with tumor inhibition by the combination of selenium and sulindac. Conclusions The selenium is synergistic with sulindac to exert maximal effects on tumor inhibition. This finding provides an important chemopreventive strategy using combination of anti-cancer agents, which has a great impact on cancer prevention and has a promising translational potential. PMID:23327547

  8. Cyclic peptide oral bioavailability: Lessons from the past.

    PubMed

    Wang, Conan K; Craik, David J

    2016-11-01

    Achieving high oral bioavailability for drugs is a key design objective in drug development. It is not surprising then that with the growing expectation of peptides as future drugs, there has also been an increasing interest in developing oral peptide therapeutics. Brought to the fore are questions such as what makes peptides orally bioavailable and how this can be achieved; questions which have inspired research into the area for decades. Early research in the area focused on linear peptides with more recent literature focusing on cyclic peptides, motivated in part by cyclic peptides like cyclosporine A that have demonstrated drug-like oral bioavailability. In this review, we take a look at research on the oral bioavailability of peptides, focusing on factors that affect passive permeability. © 2016 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 106: 901-909, 2016.

  9. Absolute Bioavailability of Tasimelteon.

    PubMed

    Torres, Rosarelis; Dressman, Marlene A; Kramer, William G; Baroldi, Paolo

    2015-01-01

    Tasimelteon is a novel dual melatonin receptor agonist and is the first treatment approved by the US Food and Drug Administration for Non-24-Hour Sleep-Wake Disorder. This study was conducted to assess the absolute bioavailability of tasimelteon and to further assess the single-dose pharmacokinetics, safety, and tolerability of oral and intravenous (IV) routes of administration of the drug. This study was an open-label, single-dose, randomized, 2-period, 2-treatment, 2-sequence, crossover study in which 14 healthy volunteers were randomly administered tasimelteon as either a 20-mg capsule or IV administration of 2 mg infused over 30 minutes. Each subject received both treatments in a random order, separated by a washout period of 5 ± 2 days. The total clearance and volume of distribution of tasimelteon, from the IV treatment, were 505 mL per minute and 42.7 L, respectively. Based on the statistical comparison of dose-corrected area under the curve to infinity, the absolute bioavailability was 38%, with a 90% confidence interval of 27%-54%. The mean elimination half-life was the same for the oral and IV routes. The exposure ratios, oral-to-IV, for metabolites M9, M11, M12, and M13, were 133.27%, 118.28%, 138.76%, and 112.36%, respectively, suggesting presystemic or first-pass metabolism. Three (21.4%) subjects experienced a treatment-emergent adverse event (TEAE) during the study. All TEAEs were mild, considered related to study medication, and consistent with what has been seen in other studies. There were no deaths, serious adverse events, or discontinuations due to TEAEs. Both tasimelteon treatments were well tolerated during the study.

  10. 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.

  11. 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.

  12. The Content and Bioavailability of Mineral Nutrients of Selected Wild and Traditional Edible Plants as Affected by Household Preparation Methods Practiced by Local Community in Benishangul Gumuz Regional State, Ethiopia.

    PubMed

    Hailu, Andinet Abera; Addis, Getachew

    2016-01-01

    Edible parts of some wild and traditional vegetables used by the Gumuz community, namely, Portulaca quadrifida, Dioscorea abyssinica, Abelmoschus esculentus, and Oxytenanthera abyssinica, were evaluated for their minerals composition and bioavailability. Mineral elements, namely, Ca, Fe, Zn, and Cu, were analyzed using Shimadzu atomic absorption spectrophotometer. Effects of household processing practices on the levels of mineral elements were evaluated and the bioavailability was predicted using antinutrient-mineral molar ratios. Fe, Zn, Ca, Cu, P, Na, and K level in raw edible portions ranged in (0.64 ± 0.02-27.0 ± 6.24), (0.46 ± 0.02-0.85 ± 0.02), (24.49 ± 1.2-131.7 ± 8.3), (0.11 ± 0.01-0.46 ± 0.04), (39.13 ± 0.34-57.27 ± 0.94), (7.34 ± 0.42-20.42 ± 1.31), and (184.4 ± 1.31-816.3 ± 11.731) mg/100 g FW, respectively. Although statistically significant losses in minerals as a result of household preparation practices were observed, the amount of nutrients retained could be valuable especially in communities that have limited alternative sources of these micronutrients. The predicted minerals' bioavailability shows adequacy in terms of calcium and zinc but not iron.

  13. Selenium status in Greenland Inuit.

    PubMed

    Hansen, Jens C; Deutch, Bente; Pedersen, Henning Sloth

    2004-09-20

    In Greenland, the human intake of selenium has always been relatively high and is closely connected to intake of the traditional food of marine origin. Analyses of historic and present day human and animal hair samples have indicated that the selenium level in the marine environment has been constant over time, while the levels in humans have declined corresponding to a decrease in intake of traditional food. The Inuit population in Greenland is in dietary transition where western-style food will increasingly dominate. As a consequence, the ample supply of selenium may not be sustained in the future. We report here the selenium status in three Greenlandic population groups, Ittoqqortoormiit and Tasiilaq on the east coast and Uummannaq on the west coast. Mean whole blood concentrations ranged from 178 microg/l in Tasiilaq men to 488 microg/l in Uummannaq men. Plasma concentrations ranged from 79 microg/l in Tasiilaq women to 113 microg/l in Uummannaq men. With increasing Se concentrations in whole blood, the plasma concentrations increased but tended to stabilise a level approximately 140 microg/l. Selenium blood levels were highly significantly correlated with long chain marine fatty acids. Dietary survey and food composition data from the west coast showed that whale skin, muktuk, is the main source of Se followed by birds, seal meat and organs, and fish. Terrestrial animals contributed only insignificantly to the selenium intake. In West Greenland, daily Se intake (235 microg/day) was estimated by dietary survey; it corresponded well with a calculated intake (220 microg/day) based on the mean blood concentration.

  14. Selenium requirement of shrimp Penaeus chinensis

    NASA Astrophysics Data System (ADS)

    Tian, Yuchuan; Liu, Fayi

    1993-09-01

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

  15. Microbial reporters of metal bioavailability

    PubMed Central

    Magrisso, Sagi; Erel, Yigal; Belkin, Shimshon

    2008-01-01

    Summary When attempting to assess the extent and the implications of environmental pollution, it is often essential to quantify not only the total concentration of the studied contaminant but also its bioavailable fraction: higher bioavailability, often correlated with increased mobility, signifies enhanced risk but may also facilitate bioremediation. Genetically engineered microorganisms, tailored to respond by a quantifiable signal to the presence of the target chemical(s), may serve as powerful tools for bioavailability assessment. This review summarizes the current knowledge on such microbial bioreporters designed to assay metal bioavailability. Numerous bacterial metal‐sensor strains have been developed over the past 15 years, displaying very high detection sensitivities for a broad spectrum of environmentally significant metal targets. These constructs are based on the use of a relatively small number of gene promoters as the sensing elements, and an even smaller selection of molecular reporter systems; they comprise a potentially useful panel of tools for simple and cost‐effective determination of the bioavailability of heavy metals in the environment, and for the quantification of the non‐bioavailable fraction of the pollutant. In spite of their inherent advantages, however, these tools have not yet been put to actual use in the evaluation of metal bioavailability in a real environmental remediation scheme. For this to happen, acceptance by regulatory authorities is essential, as is a standardization of assay conditions. PMID:21261850

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

    PubMed

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

    2008-01-01

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

  17. Serum selenium assay following serum ferritin assay

    SciTech Connect

    Stevens, R.G.; Morris, J.S.; Hann, H.L.; Pulsipher, B.; Stahlhut, M.W.

    1986-08-01

    Stored serum samples can be an important research resource into the etiology of cancer. These sera cannot be replaced and should therefore be used to best advantage. In previous epidemiologic studies, only single serum constituents have been assayed in individual serum samples. For example, serum ferritin has been examined in samples stored for as long as 10 years at -20C for a possible relation with general mortality (1) and cancer death (2). Ferritin is the tissue iron-storage protein and is therefore subject to denaturation. Serum selenium has also been examined in relation to cancer risk in a prospective manner by using stored frozen serum samples (3, 4). The interactions of a variety of serum factors in relation to cancer risk would be a desirable research goal, except that the amounts of serum typically available in frozen serum banks are less than 1 ml. It was the purpose of this investigation to determine if a radioimmunoassay for ferritin affected a subsequent neutron activation assay for selenium on the same 0.1 ml serum sample.

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

    SciTech Connect

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

    1989-01-01

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

  19. 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.

  20. Assessment of selenium nutritional status of school-age children from rural areas of China in 2002 and 2012.

    PubMed

    Liu, X; Piao, J; Li, M; Zhang, Y; Yun, C; Yang, C; Yang, X

    2016-03-01

    To assess the selenium nutritional status of 3458 school-age children recruited from rural areas using the China Nutrition and Health Survey 2002 and 2012 (CNHS 2002 and CNHS 2012). The serum selenium concentration was determined by high-resolution inductively coupled plasma mass spectrometry. The prevalence of dietary selenium intake insufficiency was calculated according to the formula suggested by and the estimated average requirements of the new Chinese Dietary Reference Intakes. The percentage of low selenium was based on the cutoff values with a serum selenium concentration below the threshold limit of clinical importance in coronary and cardiovascular diseases (<45 μg/l) and in abnormal physiological functions (<60 μg/l). The overall median serum selenium concentration was 64.3 μg/l in the CNHS 2002 and 74.2 μg/l in the CNHS 2012. The median calculated dietary selenium intake was 26.7 μg/day in the CNHS 2002 and 33.2 μg/day in the CNHS 2012 together with a 61.1% and 52.8% dietary selenium intake insufficiency in the CNHS 2002 and in the CNHS 2012. In addition, the percentages of low selenium (<45 μg/l and <60 μg/l) were 25.1 and 43.8% in the CNHS 2002 but 9.4 and 25.6% in the CHNS 2012. The selenium nutritional status of school-age children was significantly improved in the CNHS 2012 versus the CNHS 2002. However, the health risk for selenium malnutrition in school-age children remains a potential problem affecting children's health.

  1. Detailed study of selenium in soil, water, bottom sediment, and biota in the Sun River Irrigation Project, Freezout Lake Wildlife Management Area, and Benton Lake National Wildlife Refuge, west-central Montana, 1990-92

    USGS Publications Warehouse

    Nimick, D.A.; Lambing, J.H.; Palawski, D.U.; Malloy, J.C.

    1996-01-01

    Selenium and other constituents are adversely affecting water quality and creating a potential hazard to wildlife in several areas of the Sun River Irrigation Project, Freezout Lake Wildlife Management Area, and Benton Lake National Wildlife Refuge in west-central Montana. Selenium derived from Cretaceous shale and Tertiary and Quaternary deposits containing shale detritus is transported in the oxic shallow ground-water systems. At Freezout Lake Wildlife Management Area, drainage from irrigated glacial deposits is the primary source of selenium; drainage from non-irrigated farmland is a significant source locally. Benton Lake generally receives more selenium from natural runoff from its non-irrigated basin than from the trans-basin diversion of irrigation return flow. Selenium has accumulated in aquatic plants and invertebrates, fish, and water birds, particularly in wetlands that receive the largest selenium loads. Although selenium residues in biological tissue from some wetland units exceeded biological risk levels, water-bird reproduction generally has not been impaired. The highest selenium residues in biota commonly occurred in samples from Priest Butte Lakes, which also had the highest selenium concentration in wetland water. Selenium concentrations in all invertebrate samples from Priest Butte Lakes and the south end of Freezeout Lake exceeded the critical dietary threshold for water birds. Selenium delivered to wetlands accumulates in bottom sediment, predominantly in near-shore areas. Potential impacts to water quality, and presumably biota, may be greatest near the mouths of inflows. Most selenium delivered to wetlands will continue to accumulate in bottom sediment and biota.

  2. Sulfur, selenium and tellurium pseudopeptides: synthesis and biological evaluation.

    PubMed

    Shaaban, Saad; Sasse, Florenz; Burkholz, Torsten; Jacob, Claus

    2014-07-15

    A new series of sulfur, selenium and tellurium peptidomimetic compounds was prepared employing the Passerini and Ugi isocyanide based multicomponent reactions (IMCRs). These reactions were clearly superior to conventional methods traditionally used for organoselenium and organotellurium synthesis, such as classical nucleophilic substitution and coupling methods. From the biological point of view, these compounds are of considerable interest because of suspected anticancer and antimicrobial activities. While the sulfur and selenium containing compounds generally did not show either anticancer or antimicrobial activities, their tellurium based counterparts frequently exhibited antimicrobial activity and were also cytotoxic. Some of the compounds synthesized even showed selective activity against certain cancer cells in cell culture. These compounds induced a cell cycle delay in the G0/G1 phase. At closer inspection, the ER and the actin cytoskeleton appeared to be the primary cellular targets of these tellurium compounds, in line with some of our previous studies. As most of these peptidomimetic compounds also comply with Lipinski's Rule of Five, they promise good bioavailability, which needs to be studied as part of future investigations.

  3. 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

  4. Radioprotection by metals: Selenium

    NASA Astrophysics Data System (ADS)

    Weiss, J. F.; Srinivasan, V.; Kumar, K. S.; Landauer, M. R.

    The need exists for compounds that will protect individuals from high-dose acute radiation exposure in space and for agents that might be less protective but less toxic and longer acting. Metals and metal derivatives provide a small degree of radioprotection (dose reduction factor <= 1.2 for animal survival after whole-body irradiation). Emphasis is placed here on the radioprotective potential of selenium (Se). Both the inorganic salt, sodium selenite, and the organic Se compound, selenomethionine, enhance the survival of irradiated mice (60Co, 0.2 Gy/min) when injected IP either before (-24 hr and -1 hr) or shortly after (+15 min) radiation exposure. When administered at equitoxic doses (one-fourth LD10; selenomethionine = 4.0 mg/kg Se, sodium selenite = 0.8 mg/kg Se), both drugs enhanced the 30-day survival of mice irradiated at 9 Gy. Survival after 10-Gy exposure was significantly increased only after selenomethionine treatment. An advantage of selenomethionine is lower lethal and behavioral toxicity (locomotor activity depression) compared to sodium selenite, when they are administered at equivalent doses of Se. Sodium selenite administered in combination with WR-2721, S-2-(3-aminopropylamino)ethylphosphorothioic acid, enhances the radioprotective effect and reduces the lethal toxicity, but not the behavioral toxicity, of WR-2721. Other studies on radioprotection and protection against chemical carcinogens by different forms of Se are reviewed. As additional animal data and results from human chemoprevention trials become available, consideration also can be given to prolonged administration of Se compounds for protection against long-term radiation effects in space.

  5. Selenium and endocrine systems.

    PubMed

    Beckett, Geoffrey J; Arthur, John R

    2005-03-01

    The trace element selenium (Se) is capable of exerting multiple actions on endocrine systems by modifying the expression of at least 30 selenoproteins, many of which have clearly defined functions. Well-characterized selenoenzymes are the families of glutathione peroxidases (GPXs), thioredoxin reductases (TRs) and iodothyronine deiodinases (Ds). These selenoenzymes are capable of modifying cell function by acting as antioxidants and modifying redox status and thyroid hormone metabolism. Se is also involved in cell growth, apoptosis and modifying the action of cell signalling systems and transcription factors. During thyroid hormone synthesis GPX1, GPX3 and TR1 are up-regulated, providing the thyrocytes with considerable protection from peroxidative damage. Thyroidal D1 in rats and both D1 and D2 in humans are also up-regulated to increase the production of bioactive 3,5,3'-tri-iodothyronine (T3). In the basal state, GPX3 is secreted into the follicular lumen where it may down-regulate thyroid hormone synthesis by decreasing hydrogen peroxide concentrations. The deiodinases are present in most tissues and provide a mechanism whereby individual tissues may control their exposure to T3. Se is also able to modify the immune response in patients with autoimmune thyroiditis. Low sperm production and poor sperm quality are consistent features of Se-deficient animals. The pivotal link between Se, sperm quality and male fertility is GPX4 since the enzyme is essential to allow the production of the correct architecture of the midpiece of spermatozoa. Se also has insulin-mimetic properties, an effect that is probably brought about by stimulating the tyrosine kinases involved in the insulin signalling cascade. Furthermore, in the diabetic rat, Se not only restores glycaemic control but it also prevents or alleviates the adverse effects that diabetes has on cardiac, renal and platelet function.

  6. Effect of nano-sized, elemental selenium supplement on the proteome of chicken liver.

    PubMed

    Gulyas, G; Csosz, E; Prokisch, J; Javor, A; Mezes, M; Erdelyi, M; Balogh, K; Janaky, T; Szabo, Z; Simon, A; Czegledi, L

    2016-02-22

    The nano-sized (100-500 nm) selenium has higher bioavailability and relatively lower toxicity compared to other selenium forms. The objective of the present study was to compare liver proteome profiles of broiler chicken fed with control diet without Se supplementation and diet supplemented with nano-Se with 4.25 mg/kg DM. Differential proteome analyses were performed by two-dimensional gel electrophoresis (2D-PAGE) followed by tryptic digestion and protein identification by liquid chromatography-mass spectrometry (LC-MS). Seven hundred and eight spots were detected, and 18 protein spots showed significant difference in their intensity (p < 0.05) between the two groups. In response to nano-Se supplementation, the expression of 8 proteins was higher, and 5 proteins were lower in nano-Se supplemented group compared to control group. The functions of the differentially expressed proteins indicate that the high dose of selenium supplementation induced a dietary stress. Selenium supplementation may influence the metabolism of fatty acids and carbohydrates and antioxidant system, and increase the quantity of cytoskeletal actin and the expression of actin regulatory protein as well.

  7. Influence of dietary selenium on the mutagenic activity of perfusate and bile from rat liver, perfused with 1,1-dimethylhydrazine.

    PubMed

    Beije, B; Onfelt, A; Olsson, U

    1984-04-01

    The mutagenic effect of 1,1-dimethylhydrazine (UDMH) was studied in the liver perfusion/cell culture system. Male Wistar rats, fed a selenium-deficient diet with or without selenium supplementation in the drinking water, were used as liver donors. UDMH caused an increased mutation frequency in Chinese hamster V79 cells exposed in the perfusate. The effect was statistically significant with both selenium-deficient and selenium-supplemented livers. With selenium-deficient livers, a significant mutagenic effect was also obtained when V79 cells were treated with bile collected after the administration of UDMH. Bile flow and bile acid excretion were not affected by UDMH treatment of selenium-deficient or selenium-supplemented livers. There was a tendency towards reduced C-oxygenation of N,N-dimethylaniline in microsomes from selenium-deficient livers perfused with UDMH. The lactate/pyruvate ratio in the perfusate was increased by UDMH, the effect being more pronounced with selenium-deficient than selenium-supplemented livers.

  8. Potassium Intake, Bioavailability, Hypertension, and Glucose Control

    PubMed Central

    Stone, Michael S.; Martyn, Lisa; Weaver, Connie M.

    2016-01-01

    Potassium is an essential nutrient. It is the most abundant cation in intracellular fluid where it plays a key role in maintaining cell function. The gradient of potassium across the cell membrane determines cellular membrane potential, which is maintained in large part by the ubiquitous ion channel the sodium-potassium (Na+-K+) ATPase pump. Approximately 90% of potassium consumed (60–100 mEq) is lost in the urine, with the other 10% excreted in the stool, and a very small amount lost in sweat. Little is known about the bioavailability of potassium, especially from dietary sources. Less is understood on how bioavailability may affect health outcomes. Hypertension (HTN) is the leading cause of cardiovascular disease (CVD) and a major financial burden ($50.6 billion) to the US public health system, and has a significant impact on all-cause morbidity and mortality worldwide. The relationship between increased potassium supplementation and a decrease in HTN is relatively well understood, but the effect of increased potassium intake from dietary sources on blood pressure overall is less clear. In addition, treatment options for hypertensive individuals (e.g., thiazide diuretics) may further compound chronic disease risk via impairments in potassium utilization and glucose control. Understanding potassium bioavailability from various sources may help to reveal how specific compounds and tissues influence potassium movement, and further the understanding of its role in health. PMID:27455317

  9. Potassium Intake, Bioavailability, Hypertension, and Glucose Control.

    PubMed

    Stone, Michael S; Martyn, Lisa; Weaver, Connie M

    2016-07-22

    Potassium is an essential nutrient. It is the most abundant cation in intracellular fluid where it plays a key role in maintaining cell function. The gradient of potassium across the cell membrane determines cellular membrane potential, which is maintained in large part by the ubiquitous ion channel the sodium-potassium (Na+-K+) ATPase pump. Approximately 90% of potassium consumed (60-100 mEq) is lost in the urine, with the other 10% excreted in the stool, and a very small amount lost in sweat. Little is known about the bioavailability of potassium, especially from dietary sources. Less is understood on how bioavailability may affect health outcomes. Hypertension (HTN) is the leading cause of cardiovascular disease (CVD) and a major financial burden ($50.6 billion) to the US public health system, and has a significant impact on all-cause morbidity and mortality worldwide. The relationship between increased potassium supplementation and a decrease in HTN is relatively well understood, but the effect of increased potassium intake from dietary sources on blood pressure overall is less clear. In addition, treatment options for hypertensive individuals (e.g., thiazide diuretics) may further compound chronic disease risk via impairments in potassium utilization and glucose control. Understanding potassium bioavailability from various sources may help to reveal how specific compounds and tissues influence potassium movement, and further the understanding of its role in health.

  10. Bioavailability: implications for science/cleanup policy

    SciTech Connect

    Denit, Jeffery; Planicka, J. Gregory

    1998-12-01

    This paper examines the role of bioavailability in risk assessment and cleanup decisions. Bioavailability refers to how chemicals ''behave'' and their ''availability'' to interact with living organisms. Bioavailability has significant implications for exposure risks, cleanup goals, and site costs. Risk to human health and the environment is directly tied to the bioavailability of the chemicals of concern.

  11. 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.

  12. Covalent Incorporation of Selenium into Oligonucleotides for X-ray Crystal Structure Determination via MAD: Proof of Principle

    SciTech Connect

    Teplova, M.; Wilds, C.J.; Wawrzak, Z.; Tereshko, V.; Du, Q.; Carrasco, N.; Huang, Z.; Egli, M.

    2010-03-08

    Selenium was incorporated into an oligodeoxynucleotide in the form of 2'-methylseleno-uridine (U{sub Se}). The X-ray crystal structure of the duplex d(GCGTA)U{sub Se}d(ACGC){sub 2} was determined by the multiwavelength anomalous dispersion (MAD) technique and refined to a resolution of 1.3 {angstrom}, demonstrating that selenium can selectively substitute oxygen in DNA and that the resulting compounds are chemically stable. Since derivatization at the 2'-{alpha}-position with selenium does not affect the preference of the sugar for the C3'-endo conformation, this strategy is suitable for incorporating selenium into RNA. The availability of selenium-containing nucleic acids for crystallographic phasing offers an attractive alternative to the commonly used halogenated pyrimidines.

  13. Zinc bioavailability in the chick

    SciTech Connect

    Hempe, J.M.

    1987-01-01

    Methods for assessing zinc bioavailability were evaluated in the chick. A low-zinc chick diet was developed using rehydrated, spray-dried egg white autoclaved at 121 C for 30 min as the primary protein source. The relative bioavailability of zinc from soy flour and beef was determined by whole-body retention of extrinsic /sup 65/Zn, and in slope ratio assays for growth rate and tissue zinc. Compared to zinc carbonate added to an egg white-based diet, all methods gave similar estimates of approximately 100% zinc bioavailability for beef but estimates for soy flour varied widely. The slope ratio assay for growth rate gave the best estimate of zinc bioavailability for soy flour. True absorption, as measured by percent isotope retention from extrinsically labeled soy flour, was 47%.

  14. Selenium isotope ratios as indicators of selenium sources and oxyanion reduction

    USGS Publications Warehouse

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

    1999-01-01

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

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

    SciTech Connect

    Rezvanfar, Mohammad Amin; Rezvanfar, Mohammad Ali; Shahverdi, Ahmad Reza; Ahmadi, Abbas; Baeeri, Maryam; Mohammadirad, Azadeh; Abdollahi, Mohammad

    2013-02-01

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

  16. Metabolic interrelationships between arsenic and selenium

    PubMed Central

    Levander, Orville A.

    1977-01-01

    In 1938, Moxon discovered that arsenic protected against selenium toxicity. Since that time it has been shown that this protective effect of arsenic against selenium poisoning can be demonstrated in many different animal species under a wide variety of conditions. Antagonistic effects between arsenic and selenium have also been noted in teratologic experiments. Early metabolic studies showed that arsenic inhibited the expiration of volatile selenium compounds by rats injected with acutely toxic doses of both elements. This was puzzling since pulmonary excretion had long been regarded as a means by which animals could rid themselves of excess selenium. However, later work demonstrated that arsenic increased the biliary excretion of selenium. Not only did arsenic stimulate the excretion of selenium in the bile, but selenium also stimulated the excretion of arsenic in the bile. This increased biliary excretion of selenium caused by arsenic provides a reasonable rationale for the ability of arsenic to counteract the toxicity of selenium, although the chemical mechanism by which arsenic does this is not certain. The most satisfactory explanation is that these two elements react in the liver to form a detoxication conjugate which is then excreted into the bile. This is consistent with the fact that both arsenic and selenium each increase the biliary excretion of the other. Several other metabolic interactions between arsenic and selenium have been demonstrated in vitro, but their physiological significance is not clear. Although arsenic decreased selenium toxicity under most conditions, there is a pronounced synergistic toxicity between arsenic and two methylated selenium metabolites, trimethylselenonium ion or dimethyl selenide. The ecological consequences of these synergisms are largely unexplored, although it is likely that selenium methylation occurs in the environment. All attempts to promote or prevent selenium deficiency diseases in animals by feeding arsenic have

  17. Selenium immersed thermistor bolometer study

    NASA Technical Reports Server (NTRS)

    Rolls, W. H.

    1979-01-01

    The noise characteristics of thermistor bolometers immersed in layers of arsenic/selenium glass uniform in composition were examined. Using a controlled deposition technique, layers of glass were deposited, thermistor bolometers immersed, and their electrical characteristics measured after various thermal treatments. Markedly improved stability of the detector noise was observed using this new technique.

  18. Determination of selenium in urine by hydride generation atomic absorption spectrometry.

    PubMed

    Navarro, M; Lopez, H; Lopez, M C; Perez, V

    1996-01-01

    A procedure has been developed for determination of total selenium in urine by hydride generation atomic absorption spectrometry. Mineralization was performed with a nitric acid-perchloric acid mixture on a thermostated digestion block. The method was validated by comparison with the method involving mineralization in a microwave acid digestion bomb containing nitric acid and small amounts of vanadium pentoxide. Se(VI) was reduced to Se(IV) by dissolution in 7N HCl. Sample recoveries, precision studies, and analyses of a certified reference material demonstrated the reliability and accuracy of this technique. Urine samples had selenium concentrations ranging from 4.6 to 50.3 micrograms/L. These values correspond to an average of 54.9 micrograms per person per day total ingested and bioavailable Se in the daily diet.

  19. Determination of the selenium requirement in kittens.

    PubMed

    Wedekind, K J; Howard, K A; Backus, R C; Yu, S; Morris, J G; Rogers, Q R

    2003-10-01

    The purpose of this study was to determine the selenium (Se) requirement in kittens. Thirty-six specific-pathogen-free kittens (9.8 weeks old) were utilized in a randomized complete block design to determine the Se requirement in cats with gender and weight used as blocking criteria. Kittens were fed a low Se (0.02 mg/kg Se) torula yeast-based diet for 5 weeks (pre-test) after which an amino acid-based diet (0.027 mg Se/kg diet) was fed for 8 weeks (experimental period). Six levels of Se (0, 0.05, 0.075, 0.10, 0.20 and 0.30 mg Se/kg diet) as Na2SeO3 were added to the diet and were used to construct a response curve. Response variables included Se concentrations and Se-dependent glutathione peroxidase activities (GSHpx) in plasma and red blood cells (RBC) as well as plasma total T3 (TT3) and total T4 (TT4). No significant changes in food intake, weight gain or clinical signs of Se deficiency were noted. Estimates of the kitten's Se requirement (i.e. breakpoints) were determined for RBC and plasma GSHpx (0.12 and 0.15 mg Se/kg diet, respectively), but no definitive breakpoint was determined for plasma Se. Plasma TT3 increased linearly, whereas plasma TT4 and the ratio of TT4 : TT3 decreased in a quadratic fashion to dietary Se concentration. The requirement estimate determined in this study (0.15 mg Se/kg) for kittens is in close agreement with other species. As pet foods for cats contain a high proportion of animal protein with a Se bioavailability of 30%, it is recommended that commercial diets for cats contain 0.5 mg Se/kg DM.

  20. Studies on vitamin E and selenium deficiency in young pigs. I. Hematological and biochemical changes.

    PubMed

    Fontaine, M; Valli, V E; Young, L G; Lumsden, J H

    1977-01-01

    Pigs which were deficient in vitamin E and/or selenium had the following parameters weekly determined from six to 13 weeks of age: Packed cell volume, hemoglobin concentration, red cell and white cell counts, red cell indices, reticulocyte count, serum iron, serum total iron binding capacity, myeloid: erythroid ratio, serum glutamic-oxaloacetic transaminase and creatine phosphokinase activities and body weight. Except for the myeloid:erythroid ratio and serum creatine phosphokinase activity, these parameters were not found to be significantly affected by either vitamin E deficiency, selenium deficiency or deficiency of both. The myeloid:erythroid ratio was increased (p less than 0.01) in association with selenium deficiency, which tends to indicate decreased erythropoiesis but was not reflected in the peripheral red cell picture. Evidence of dyserythropoiesis was not found to be a significant feature in serial bone marrow aspiration biopsies of vitamin E and/or selenium deficient pigs. Even if the serum glutamic-oxaloacetic transaminase activities were not found to be significantly affected by either vitamin E deficiency, selenium deficiency or deficiency in both as compared to replete animals, a few animals, especially in the group deficient in both vitamin E and selenium, presented quite marked transient increases of serum glutamic-oxaloacetic transaminase activity which was interpreted to reflect the occurrence of acute episodes of hepatosis dietetica. Serum creatine phosphokinase activities were found to be increased in association with vitamin E deficiency (p less than 0.01), selenium deficiency (less than 0.05) and the interaction was also significant (p less than 0.01). It was concluded that the serum creatine phosphokinase activity increases reflect the occurrence of subclinical muscular dystrophy and that vitamin E and selenium deficiencies have marked additive effects in the induction of skeletal muscular dystrophy.

  1. 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.

  2. Chemical form of selenium in naturally selenium-rich lentils (Lens culinaris L.) from Saskatchewan.

    PubMed

    Thavarajah, Dil; Vandenberg, Albert; George, Graham N; Pickering, Ingrid J

    2007-09-05

    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.

  3. 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.

  4. Scaffold of Selenium Nanovectors and Honey Phytochemicals for Inhibition of Pseudomonas aeruginosa Quorum Sensing and Biofilm Formation

    PubMed Central

    Prateeksha; Singh, Braj R.; Shoeb, M.; Sharma, S.; Naqvi, A. H.; Gupta, Vijai K.; Singh, Brahma N.

    2017-01-01

    Honey is an excellent source of polyphenolic compounds that are effective in attenuating quorum sensing (QS), a chemical process of cell-to-cell communication system used by the opportunistic pathogen Pseudomonas aeruginosa to regulate virulence and biofilm formation. However, lower water solubility and inadequate bioavailability remains major concerns of these therapeutic polyphenols. Its therapeutic index can be improved by using nano-carrier systems to target QS signaling potently. In the present study, we fabricated a unique drug delivery system comprising selenium nanoparticles (SeNPs; non-viral vectors) and polyphenols of honey (HP) for enhancement of anti-QS activity of HP against P. aeruginosa PAO1. The developed selenium nano-scaffold showed superior anti-QS activity, anti-biofilm efficacy, and anti-virulence potential in both in-vitro and in-vivo over its individual components, SeNPs and HP. LasR is inhibited by selenium nano-scaffold in-vitro. Using computational molecular docking studies, we have also demonstrated that the anti-virulence activity of selenium nano-scaffold is reliant on molecular binding that occurs between HP and the QS receptor LasR through hydrogen bonding and hydrophobic interactions. Our preliminary investigations with selenium-based nano-carriers hold significant promise to improve anti-virulence effectiveness of phytochemicals by enhancing effective intracellular delivery. PMID:28386534

  5. Scaffold of Selenium Nanovectors and Honey Phytochemicals for Inhibition of Pseudomonas aeruginosa Quorum Sensing and Biofilm Formation.

    PubMed

    Prateeksha; Singh, Braj R; Shoeb, M; Sharma, S; Naqvi, A H; Gupta, Vijai K; Singh, Brahma N

    2017-01-01

    Honey is an excellent source of polyphenolic compounds that are effective in attenuating quorum sensing (QS), a chemical process of cell-to-cell communication system used by the opportunistic pathogen Pseudomonas aeruginosa to regulate virulence and biofilm formation. However, lower water solubility and inadequate bioavailability remains major concerns of these therapeutic polyphenols. Its therapeutic index can be improved by using nano-carrier systems to target QS signaling potently. In the present study, we fabricated a unique drug delivery system comprising selenium nanoparticles (SeNPs; non-viral vectors) and polyphenols of honey (HP) for enhancement of anti-QS activity of HP against P. aeruginosa PAO1. The developed selenium nano-scaffold showed superior anti-QS activity, anti-biofilm efficacy, and anti-virulence potential in both in-vitro and in-vivo over its individual components, SeNPs and HP. LasR is inhibited by selenium nano-scaffold in-vitro. Using computational molecular docking studies, we have also demonstrated that the anti-virulence activity of selenium nano-scaffold is reliant on molecular binding that occurs between HP and the QS receptor LasR through hydrogen bonding and hydrophobic interactions. Our preliminary investigations with selenium-based nano-carriers hold significant promise to improve anti-virulence effectiveness of phytochemicals by enhancing effective intracellular delivery.

  6. Daily dietary selenium intake and hair selenium content in a high selenium area of Enshi, China

    USDA-ARS?s Scientific Manuscript database

    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...

  7. A reliable solid phase microextraction-gas chromatography-triple quadrupole mass spectrometry method for the assay of selenomethionine and selenomethylselenocysteine in aqueous extracts: difference between selenized and not-enriched selenium potatoes.

    PubMed

    Gionfriddo, Emanuela; Naccarato, Attilio; Sindona, Giovanni; Tagarelli, Antonio

    2012-10-17

    A new analytical approach is exploited in the assay of selenium speciation in selenized and not selenium enriched potatoes based on the widely available solid-phase microextraction (SPME) coupled to-GC-triple quadrupole mass spectrometry (SPME-GC-QqQ MS) method. The assay of selenomethionine (SeMet) and selenomethylselenocysteine (SeMeSeCys) in potatoes here reported provides clues to the effectiveness of SPME technique combined with gas chromatography-tandem mass spectrometry, which could be of general use. For the exploitation of the GC method, the selected analytes were converted into their N(O,S)-alkoxycarbonyl alkyl esters derivatives by direct treatment with alkyl chloroformate in aqueous extracts. The performance of five SPME fibers and three chloroformates were tested in univariate mode and the best results were obtained using the divinylbenzene/carboxen/polydimethylsiloxane fiber and propylchloroformate. The variables affecting the efficiency of SPME analysis were optimized by the multivariate approach of design of experiment (DoE) and, in particular, a central composite design (CCD) was applied. Tandem mass spectrometry in selected reaction monitoring (SRM) has allowed the elimination of matrix interferences, providing reconstructed chromatograms with well-resolved peaks and the achievement of very satisfactory detection and quantification limits. Both precision and recovery of the proposed protocol tested at concentration of 8 and 40 μg kg(-1) (dry matter), offered values ranging from 82.3 to 116.3% and from 8.5 to 13.1% for recovery and precision, respectively. The application of the method to commercial samples of selenized and not selenium enriched potatoes proved that the Se fertilization increases significantly the concentration of these bioavailable selenoamino acids.

  8. Effects of dissolved organic matter on toxicity and bioavailability of copper for lettuce sprouts.

    PubMed

    Inaba, Shoko; Takenaka, Chisato

    2005-05-01

    It is well known that dissolved organic matter in soil solution may affect the toxicity or bioavailability of heavy metals to plants, but existing information on various organic substances is insufficient for treating problems with heavy metal-contaminated soils. To clarify how dissolved organic matter alters the toxicity and bioavailability of metals, we germinated lettuce seeds exposed to solutions containing Cu and several kinds of dissolved organic matters. Low molecular weight organic acids (citric, malic, and oxalic acids) increased the toxicity and bioavailability of Cu, but low concentrations of the synthetic chelators ethylenediamine tetra-acetic acid (EDTA) and diethylenetriamine penta-acetic acid (DTPA) decreased the toxicity and bioavailability of Cu. In contrast, humic acid appeared to be the most effective organic substance for detoxifying Cu, even though it did not significantly decrease the bioavailability of Cu. Consequently, the bioavailability and toxic effects of Cu in soil depend on the nature of coexisting organic substances in the soil solution.

  9. Vitamin D bioavailability: state of the art.

    PubMed

    Borel, P; Caillaud, D; Cano, N J

    2015-01-01

    There has been renewed interest in vitamin D since numerous recent studies have suggested that besides its well-established roles in bone metabolism and immunity, vitamin D status is inversely associated with the incidence of several diseases, e.g., cancers, cardio-vascular diseases, and neurodegenerative diseases. Surprisingly, there is very little data on factors that affect absorption of this fat-soluble vitamin, although it is acknowledged that dietary vitamin D could help to fight against the subdeficient vitamin D status that is common in several populations. This review describes the state of the art concerning the fate of vitamin D in the human upper gastrointestinal tract and on the factors assumed to affect its absorption efficiency. The main conclusions are: (i) ergocalciferol (vitamin D2), the form mostly used in supplements and fortified foods, is apparently absorbed with similar efficiency to cholecalciferol (vitamin D3, the main dietary form), (ii) 25-hydroxyvitamin D (25OHD), the metabolite produced in the liver, and which can be found in foods, is better absorbed than the nonhydroxy vitamin D forms cholecalciferol and ergocalciferol, (iii) the amount of fat with which vitamin D is ingested does not seem to significantly modify the bioavailability of vitamin D3, (iv) the food matrix has apparently little effect on vitamin D bioavailability, (v) sucrose polyesters (Olestra) and tetrahydrolipstatin (orlistat) probably diminish vitamin D absorption, and (vi) there is apparently no effect of aging on vitamin D absorption efficiency. We also find that there is insufficient, or even no data on the following factors suspected of affecting vitamin D bioavailability: (i) effect of type and amount of dietary fiber, (ii) effect of vitamin D status, and (iii) effect of genetic variation in proteins involved in its intestinal absorption. In conclusion, further studies are needed to improve our knowledge of factors affecting vitamin D absorption efficiency

  10. Selenium in arid and semiarid soils

    SciTech Connect

    Burau, R.G. )

    1989-02-01

    Selenium is an essential element for many life forms but can cause toxicity when present at high levels in animal diets. The chemistry and particularly the geochemistry of selenium is similar to that of sulfur. Selenate, the selenium analog of sulfate, is the key to understanding selenium toxicity in arid and semiarid areas. Selenate salts of calcium, magnesium, sodium, and potassium are generally more soluble than those of sulfate. Also, selenate is not significantly adsorbed in neutral and alkaline soils. Therefore, selenate is highly mobile, causing it to be transferred readily from place to place dissolved in water, where it also enters biological food webs by plant uptake. Within plants, selenium is incorporated into organic compounds by forming C-Se bonds. Three other factors that control selenium in soil-water-plant systems are soil parent material. 14 refs.

  11. Acute toxicity of selenium compounds commonly found in selenium-accumulator plants

    USDA-ARS?s Scientific Manuscript database

    Selenium (Se) accumulating plants, such as Astragalus spp. and Aster spp., can accumulate up to 8,000 to 13,000 ppm selenium and can cause acute toxicity when consumed by livestock or wildlife. Recent research has shown that much of the selenium in some Se-accumulating plants is stored as selenate ...

  12. 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

  13. Potential for bioavailability to limit degradation of herbicides in unsaturated soils

    USDA-ARS?s Scientific Manuscript database

    It is well established that biodegradation of organic compounds in soils can be limited by bioavailability if sorption reduces the pool of material available in solution. Bioavailability can also affect herbicidal function, reported herein in the complex processes of activation and degradation of t...

  14. 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.

  15. Molybdenum accumulation, tolerance and molybdenum-selenium-sulfur interactions in Astragalus selenium hyperaccumulator and nonaccumulator species.

    PubMed

    DeTar, Rachael Ann; Alford, Élan R; Pilon-Smits, Elizabeth A H

    2015-07-01

    Some species hyperaccumulate selenium (Se) upwards of 0.1% of dry weight. This study addressed whether Se hyperaccumulators also accumulate and tolerate more molybdenum (Mo). A field survey revealed on average 2-fold higher Mo levels in three hyperaccumulator Astragali compared to three nonaccumulator Astragali, which were not significantly different. Next, a controlled study was performed where hyperaccumulators Astragalus racemosus and Astragalus bisulcatus were compared with nonaccumulators Astragalus drummondii and Astragalus convallarius for Mo accumulation and tolerance, alone or in the presence of Se. When grown on agar media with 0, 12, 24 or 48 mg L(-1) molybdate and/or 0, 1.6 or 3.2 mg L(-1) selenate, all species decreased in biomass with increasing Mo supply. Selenium did not impact biomass at the supplied levels. All Astragali accumulated Mo upwards of 0.1% of dry weight. Selenium levels were up to 0.08% in Astragalus racemosus and 0.04% Se in the other species. Overall, there was no correlation between Se hyperaccumulation and Mo accumulation capacity. However, the hyperaccumulators and nonaccumulators differed in some respects. While none of the species had a higher tissue Mo to sulfur (S) ratio than the growth medium, nonaccumulators had a higher Mo/S ratio than hyperaccumulators. Also, while molybdate and selenate reduced S accumulation in nonaccumulators, it did not in hyperaccumulators. Furthermore, A. racemosus had a higher Se/S ratio than its medium, while the other species did not. Additionally, Mo and Se treatment affected S levels in nonaccumulators, but not in hyperaccumulators. In conclusion, there is no evidence of a link between Se and Mo accumulation and tolerance in Astragalus. Sulfate transporters in hyperaccumulating Astragali appear to have higher sulfate specificity over other oxyanions, compared to nonaccumulators, and A. racemosus may have a transporter with enhanced selenate specificity relative to sulfate or molybdate.

  16. Protocol for aquatic hazard assessment of selenium

    SciTech Connect

    Lemly, A.D.

    1995-05-24

    A procedure is described for conducting an aquatic hazard assessment of selenium. Hazard is characterized in terms of the potential for food-chain bioaccumulation and reproductive impairment in fish and aquatic birds, which are the most sensitive biological responses for estimating ecosystem-level impacts of selenium contamination. Five degrees of hazard are possible depemding on the expected environmental concentrations of selenium, exposure of fish and aquatic birds to toxic concentrations, and resultant potential for reproductive impairment. An example is given to illustrate how the protocol is applied to selenium data from a typical contaminant monitoring program.

  17. Increased hair selenium concentration in hyperlipidemic patients

    PubMed Central

    Fülöp, Péter; Seres, Ildikó; Jenei, Zoltán; Juhász, Imre; Paragh, György

    2013-01-01

    Selenium is an essential trace element with potential anti-atherogenic and antioxidant effects. Experimental data suggest that selenium might be beneficial in the prevention of atherosclerosis and its complications, whereas human epidemiological studies have yielded conflicting results. Data on hair selenium status in hyperlipidemic patients are still lacking. Therefore, we analysed selenium concentrations by X-ray fluorescence in the hair of 81 statin-naïve patients with newly diagnosed Fredrickson-type IIa and IIb hyperlipoproteinemia and compared their data with 43 healthy volunteers. We also assessed the frequency of other classical risk factors of atherosclerosis. Hair selenium levels were found to be significantly higher in hyperlipidemic patients compared with volunteers with normal lipid levels. Also, a significantly increased number of traditional atherosclerosis risk factors were observed in hyperlipidemic patients with hair selenium concentrations above the median in contrast to those with below. Our results suggest that high hair selenium status might be associated with adverse blood lipid profile together with an increased number of traditional risk factors in a selenium-deplete population. These findings warrant further investigations to study the impact of selenium supplementation on the incidence of cardiovascular events. PMID:23402643

  18. 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

  19. Selenium in ruminant nutrition: a review.

    PubMed

    Ammerman, C B; Miller, S M

    1975-10-01

    The early interest in selenium related primarily to its toxicity, but since 1957 the element has been recognized as a dietary essential. The dietary requirement for selenium by most species is about .1 ppm. Deficiencies of selenium in cattle and sheep have been confirmed under natural grazing conditions in many countries of the world. Overt signs of inadequacy such as white muscle disease (nutritional muscular dystrophy) occur primarily in young calves or lambs born to selenium deficient dams. Infertility has increased in ewes grazing pastures low in selenium. In general, signs of deficiency have not occurred in older animals such as finishing beef cattle and lactating dairy cows. Subclinical deficiencies of selenium are not determined easily, however, and thus an inadequacy of the element may be limiting maximum animal performance under certain circumstances of drylot feeding. The current nutritional status of ruminant animals in many geographical areas and involving various feeding programs with this element has not been established. The recent widespread deficiency problems with nonruminants suggest that such an assessment should be made. Concentration of selenium in tissue, particularly in the liver, has been used in establishing selenium status of the animal. With lambs glutathione peroxidase activity in certain tissues may be a more accurate indicator of selenium adequacy than is selenium content of the tissue. Supplemental sodium selenite and sodium selenate by either oral administration or parenteral injection have prevented clinical signs of selenium deficiency and animal losses in both ruminant and nonruminant animals. Heavy pellets containing elemental selenium for placement in the rumen have proved effective. In general, organic forms of selenium are absorbed more readily by animals than are inorganic compounds. The dietary requirements for selenium and its metabolism are influenced by many nutrient interrelationships, including its interactions with

  20. 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.

  1. Kinetic determination of selenium in biological material

    SciTech Connect

    Efremenko, O.A.; Krasnyuk, I.I.; Kudrin, A.N.; Rudenko, B.A.

    1986-05-10

    A very promising method for selenium determination is a kinetic analytical procedure that combines the simplicity and availability of physical instrumentation with a low analyte detection limit. This paper reports a modification of the method to enable the determination of selenium in rat blood and involves decomposing the sample with a mixture of nitric and perchloric acids, separation of the selenium (IV) from other decomposition products, and quantitatively determining selenium by the described kinetic method using the indicator reaction of iron (II) edetate oxidation by sodium nitrate.

  2. 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.

  3. 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.

  4. Life-quality indicators in elderly people are influenced by selenium status.

    PubMed

    González, Sonia; Huerta, José M; Fernández, Serafina; Patterson, Angeles M; Lasheras, Cristina

    2007-02-01

    Selenium is of fundamental importance to human health. Our aim was to evaluate the effect of selenium (intake and serum levels) on subjective indicators of quality of life in older people, such as self-perceived health, chewing ability and physical activity. The sample was a cohort of 227 elderly people (93 men and 134 women) residing in 14 nursing homes in Asturias (Spain). Mean age +/- SD was 72.9+/-7.2 y and 76.4+/-5.9 y, for men and women respectively. Information was collected in personal interviews. Dietary intake was recorded by means of a food-frequency questionnaire. Selenium was determined in serum by graphite-furnace atomic absorption spectrometry. Serum selenium was associated with self-perceived health, chewing ability and physical activity in this sample. Subjects in the upper tertile of serum selenium had more than twice as much probability (Odds Ratios, 2.05 to 3.157) of reporting good health status, good chewing ability and of doing more than 60 min of exercise/day. The maintenance of good serum selenium levels is important, since it may affect the self-perception of health, chewing ability, or physical activity and, consequently, the quality of life in elderly people.

  5. 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.

  6. Auranofin disrupts selenium metabolism in Clostridium difficile by forming a stable Au-Se adduct.

    PubMed

    Jackson-Rosario, Sarah; Cowart, Darin; Myers, Andrew; Tarrien, Rebecca; Levine, Rodney L; Scott, Robert A; Self, William Thomas

    2009-05-01

    Clostridium difficile is a nosocomial pathogen whose incidence and importance are on the rise. Previous work in our laboratory characterized the central role of selenoenzyme-dependent Stickland reactions in C. difficile metabolism. In this work we have identified, using mass spectrometry, a stable complex formed upon reaction of auranofin (a gold-containing drug) with selenide in vitro. X-ray absorption spectroscopy supports the structure that we proposed on the basis of mass-spectrometric data. Auranofin potently inhibits the growth of C. difficile but does not similarly affect other clostridia that do not utilize selenoproteins to obtain energy. Moreover, auranofin inhibits the incorporation of radioisotope selenium ((75)Se) in selenoproteins in both Escherichia coli, the prokaryotic model for selenoprotein synthesis, and C. difficile without impacting total protein synthesis. Auranofin blocks the uptake of selenium and results in the accumulation of the auranofin-selenide adduct in the culture medium. Addition of selenium in the form of selenite or L-selenocysteine to the growth medium significantly reduces the inhibitory action of auranofin on the growth of C. difficile. On the basis of these results, we propose that formation of this complex and the subsequent deficiency in available selenium for selenoprotein synthesis is the mechanism by which auranofin inhibits C. difficile growth. This study demonstrates that targeting selenium metabolism provides a new avenue for antimicrobial development against C. difficile and other selenium-dependent pathogens.

  7. Interplay between Selenium Levels, Selenoprotein Expression, and Replicative Senescence in WI-38 Human Fibroblasts*

    PubMed Central

    Legrain, Yona; Touat-Hamici, Zahia; Chavatte, Laurent

    2014-01-01

    Selenium is an essential trace element, which is incorporated as selenocysteine into at least 25 selenoproteins using a unique translational UGA-recoding mechanism. Selenoproteins are important enzymes involved in antioxidant defense, redox homeostasis, and redox signaling pathways. Selenium levels decline during aging, and its deficiency is associated with a marked increase in mortality for people over 60 years of age. Here, we investigate the relationship between selenium levels in the culture medium, selenoprotein expression, and replicative life span of human embryonic lung fibroblast WI-38 cells. Selenium levels regulate the entry into replicative senescence and modify the cellular markers characteristic for senescent cells. Whereas selenium supplementation extends the number of population doublings, its deficiency impairs the proliferative capacity of WI-38 cells. We observe that the expression of several selenoproteins involved in antioxidant defense is specifically affected in response to cellular senescence. Their expression is selectively controlled by the modulation of mRNA levels and translational recoding efficiencies. Our data provide novel mechanistic insights into how selenium impacts the replicative life span of mammalian cells by identifying several selenoproteins as new targets of senescence. PMID:24425862

  8. Neonatal erythrocyte glutathione peroxidase deficiency as a consequence of selenium imbalance during pregnancy.

    PubMed

    Perona, G; Guidi, G C; Piga, A; Cellerino, R; Milani, G; Colautti, P; Moschini, G; Stievano, B M

    1979-08-01

    The red blood cell (RBC) glutathione peroxidase (GSH-Px) activity and routine haematological parameters were measured in 38 healthy north Italian full-term pregnant women and in their newborn infants. In 31 pairs the serum selenium concentration was also measured. Data were compared with those of 20 normal adult controls (10 males and 10 females). Newborn infants exhibited significantly lower RBC GSH-Px activity and serum selenium concentrations than adult controls. Pregnant women had serum selenium values intermediate between those of adult female controls and their newborn infants. In both the pregnant women and newborns the RBC GSH-Px activity correlated with the level of selenium in serum which suggests that the neonatal RBC GSH-Px deficiency may be partially due to insufficient availability of selenium during pregancy. Factors other than selenium concentration, e.g. hormonal and genetic, might also affect the RBC GSH-Px activity as suggested by sex differences and mother/child concordances in enzyme activity found in our cases.

  9. Interplay between selenium levels, selenoprotein expression, and replicative senescence in WI-38 human fibroblasts.

    PubMed

    Legrain, Yona; Touat-Hamici, Zahia; Chavatte, Laurent

    2014-02-28

    Selenium is an essential trace element, which is incorporated as selenocysteine into at least 25 selenoproteins using a unique translational UGA-recoding mechanism. Selenoproteins are important enzymes involved in antioxidant defense, redox homeostasis, and redox signaling pathways. Selenium levels decline during aging, and its deficiency is associated with a marked increase in mortality for people over 60 years of age. Here, we investigate the relationship between selenium levels in the culture medium, selenoprotein expression, and replicative life span of human embryonic lung fibroblast WI-38 cells. Selenium levels regulate the entry into replicative senescence and modify the cellular markers characteristic for senescent cells. Whereas selenium supplementation extends the number of population doublings, its deficiency impairs the proliferative capacity of WI-38 cells. We observe that the expression of several selenoproteins involved in antioxidant defense is specifically affected in response to cellular senescence. Their expression is selectively controlled by the modulation of mRNA levels and translational recoding efficiencies. Our data provide novel mechanistic insights into how selenium impacts the replicative life span of mammalian cells by identifying several selenoproteins as new targets of senescence.

  10. 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.

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

    PubMed

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

    2009-01-01

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

  12. 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

  13. Multispecies Biofilms Transform Selenium Oxyanions into Elemental Selenium Particles: Studies Using Combined Synchrotron X-ray Fluorescence Imaging and Scanning Transmission X-ray Microscopy

    SciTech Connect

    Yang, Soo In; George, Graham N.; Lawrence, John R.; Kaminskyj, Susan G. W.; Dynes, James J.; Lai, Barry; Pickering, Ingrid J.

    2016-10-04

    Selenium (Se) is an element of growing environmental concern, because low aqueous concentrations can lead to biomagnification through the aquatic food web. Biofilms, naturally occurring microbial consortia, play numerous important roles in the environment, especially in biogeochemical cycling of toxic elements in aquatic systems. The complexity of naturally forming multispecies biofilms presents challenges for characterization because conventional microscopic techniques require chemical and physical modifications of the sample. Here, multispecies biofilms biotransforming selenium oxyanions were characterized using X-ray fluorescence imaging (XFI) and scanning transmission X-ray microscopy (STXM). These complementary synchrotron techniques required minimal sample preparation and were applied correlatively to the same biofilm areas. Sub-micrometer XFI showed distributions of Se and endogenous metals, while Se K-edge X-ray absorption spectroscopy indicated the presence of elemental Se (Se0). Nanoscale carbon K-edge STXM revealed the distributions of microbial cells, extracellular polymeric substances (EPS), and lipids using the protein, saccharide, and lipid signatures, respectively, together with highly localized Se0 using the Se LIII edge. Transmission electron microscopy showed the electron-dense particle diameter to be 50–700 nm, suggesting Se0 nanoparticles. The intimate association of Se0 particles with protein and polysaccharide biofilm components has implications for the bioavailability of selenium in the environment.

  14. The bioavailability of dietary calcium.

    PubMed

    Guéguen, L; Pointillart, A

    2000-04-01

    This update focuses on the bioavailability of dietary calcium for humans. Fundamentals of calcium metabolism, intestinal absorption, urinary excretion and balance are recalled. Dietary factors, especially lactose and other milk components, influencing calcium bioavailability at intestinal and renal levels are reviewed. A critical examination of all the methods used for evaluating calcium bioavailability is made. This includes in vitro assays, classical and isotopic balances, urinary excretion, isotope labeling in the urine, plasma and bones, long term evaluation of bone mineralization and the use of biological bone markers. Importance and advantages of animal models are discussed. The state of the art in the comparative bioavailability of calcium in foods is detailed including a comparison of sources of calcium (dairy products and calcium salts) in human studies and in some animal studies, casein phosphopeptides, proteins, lactose and lactase and their relation with calcium bioavailability (in humans and rats). An update on the consumption of dairy products and bone mass is presented. Emphasis on peculiarities and advantages of calcium in milk and dairy products is given.

  15. Studies on vitamin E and selenium deficiency in young pigs. IV. Effect on coagulation system.

    PubMed

    Fontaine, M; Valli, V E; Young, L G

    1977-01-01

    An evaluation of the coagulation system has been conducted in vitamin E and/or selenium deficient swine. The partial thromboplastin time, plasma fibrinogen concentration, platelet lipid peroxides, as well as the fibrinogen/fibrin degradation products were not found to be significantly affected by either vitamin E deficiency, selenium deficiency, or deficiency of both. With selenium deficiency, the prothrombin time was shortened (p less than 0.05). The platelet count and platelet turnover were greatly decreased by both vitamin E (p less than 0.001) and selenium deficiency (p less than 0.005). Further-more, the survival of platelets labelled with 75Se-selenomethionine and the per cent isotope incorporated into platelets were reduced (p less than 0.05 and p less than 0.005) in association with vitamin E deficiency, but not with selenium deficiency. These results were interpreted as evidence of a platelet production defect and possibly a platelet function defect in vitamin E deficient animals. Selenium deficiency were also associated with decreased (p less than 0.05) survival of fibrinogen labelled with 75Se-selenomethionine and increased (p less than 0.05) turnover of fibrinogen. From these fibrinogen kinetic findings, it was considered that chronic low grade disseminated intravascular coagulation possibly occurs in selenium deficient animals, probably in relation to the development of hepatosis dietetica or widespread microvascular damage. However, other possibilities such as increased fibrinogenolysis in relation with hepatosis dietetica or an intrinsic fibrinogen defect due to selenium deficiency also need to be taken into consideration and have not been ruled out in the present study.

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

    PubMed

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

    2015-01-01

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

  17. Sulfur and selenium antioxidants: challenging radical scavenging mechanisms and developing structure-activity relationships based on metal binding.

    PubMed

    Zimmerman, Matthew T; Bayse, Craig A; Ramoutar, Ria R; Brumaghim, Julia L

    2015-04-01

    Because sulfur and selenium antioxidants can prevent oxidative damage, numerous animal and clinical trials have investigated the ability of these compounds to prevent the oxidative stress that is an underlying cause of cardiovascular disease, Alzheimer's disease, and cancer, among others. One of the most common sources of oxidative damage is metal-generated hydroxyl radical; however, very little research has focused on determining the metal-binding abilities and structural attributes that affect oxidative damage prevention by sulfur and selenium compounds. In this review, we describe our ongoing investigations into sulfur and selenium antioxidant prevention of iron- and copper-mediated oxidative DNA damage. We determined that many sulfur and selenium compounds inhibit Cu(I)-mediated DNA damage and that DNA damage prevention varies dramatically when Fe(II) is used in place of Cu(I) to generate hydroxyl radical. Oxidation potentials of the sulfur or selenium compounds do not correlate with their ability to prevent DNA damage, highlighting the importance of metal coordination rather than reactive oxygen species scavenging as an antioxidant mechanism. Additional gel electrophoresis, mass spectrometry, and UV-visible studies confirmed sulfur and selenium antioxidant binding to Cu(I) and Fe(II). Ultimately, our studies established that both the hydroxyl-radical-generating metal ion and the chemical environment of the sulfur or selenium significantly affect DNA damage prevention and that metal coordination is an essential mechanism for these antioxidants.

  18. Effect of dietary organic versus inorganic selenium in laying hens on the productivity, selenium distribution in egg and selenium content in blood, liver and kidney.

    PubMed

    Jiakui, Li; Xiaolong, Wang

    2004-01-01

    We investigated the effect of organic versus inorganic dietary selenium in laying hens on the productivity, selenium distribution in egg and selenium content in blood, liver and kidney. Sixty Leghorn laying hens were fed a basic diet containing 0.23mg Se/kg DM (dry matter) for 2 weeks and then were allocated randomly into three groups. Thereafter, the hens were given the same basic diet without supplementation, or with 0.51 mg Se/kg DM as sodium selenite (SS) or Se-malt (SM). During the experiment, egg rate and dietary intake were recorded, blood was sampled on days 10 and 20, and six eggs were sampled on days 8, 16 and 24 from each treatment group for Se content determination. At the end of the experiment, 10 hens from each treatment were slaughtered, and liver and kidney were sampled for the determination of Se content. The result showed that with the increase of dietary Se level, the Se content in egg, blood, liver and kidney was elevated (P < 0.05), but the hens' productivity was not affected. SS increased liver Se content more than SM (P < 0.05), while the Se content both in blood and kidney did not differ significantly between the SS and SM treatments. Se from SM and SS mainly deposited in the egg yolk. This suggests that the metabolic route of Se from SM is similar to that of Se from SS in laying hens.

  19. Review of selenium thermodynamic data

    NASA Astrophysics Data System (ADS)

    Cowan, C. E.

    1988-02-01

    This report assesses the accuracy and completeness of available thermodynamic data on selenium. A review of experimental methods from published literature on selenium thermodynamic data focused on chemical reactions responsible for the formation of both aqueous complexes and solid phases of selenate, selenite, and selenide. The reviewer selected best data values, based on the methods used for estimating thermodynamic data. After inclusion of these values into the MINTEQ model, a validation study evaluated model performance for selenite and selenide solid phases. Lack of selenate data precluded model validation for this compound. The review furnished data on 22 aqueous complexes of selenite, 15 of selenide, and 17 of selenate, as well as 21 solid phases of selenite, 20 of selenide and 8 of selenate. These data proved inadequate to represent the formation of species in the solid phase. The validation study gave inconclusive predictions of selenite and selenide solubility and could not be used to assess the accuracy or completeness of the thermodynamic data.

  20. Exploring the structural basis for selenium/mercury antagonism in Allium fistulosum

    SciTech Connect

    McNear, Jr., David H.; Afton, Scott E.; Caruso, Joseph A.

    2012-12-10

    While continuing efforts are devoted to studying the mutually protective effect of mercury and selenium in mammals, few studies have investigated the mercury-selenium antagonism in plants. In this study, we report the metabolic fate of mercury and selenium in Allium fistulosum (green onion) after supplementation with sodium selenite and mercuric chloride. Analysis of homogenized root extracts via capillary reversed phase chromatography coupled with inductively coupled plasma mass spectrometry (capRPLC-ICP-MS) suggests the formation of a mercury-selenium containing compound. Micro-focused synchrotron X-ray fluorescence mapping of freshly excised roots show Hg sequestered on the root surface and outlining individual root cells, while Se is more evenly distributed throughout the root. There are also discrete Hg-only, Se-only regions and an overall strong correlation between Hg and Se throughout the root. Analysis of the X-ray absorption near edge structure (XANES) spectra show a 'background' of methylselenocysteine within the root with discrete spots of SeO{sub 3}{sup 2-}, Se{sup 0} and solid HgSe on the root surface. Mercury outlining individual root cells is possibly binding to sulfhydryl groups or plasma membrane or cell wall proteins, and in some places reacting with reduced selenium in the rhizosphere to form a mercury(II) selenide species. Together with the formation of the root-bound mercury(II) selenide species, we also report on the formation of cinnabar (HgS) and Hg{sup 0} in the rhizosphere. The results presented herein shed light on the intricate chemical and biological processes occurring within the rhizosphere that influence Hg and Se bioavailability and will be instrumental in predicting the fate and assisting in the remediation of these metals in the environment and informing whether or not fruit and vegetable food selection from aerial plant compartments or roots from plants grown in Hg contaminated soils, are safe for consumption.

  1. Exploring the structural basis for selenium/mercury antagonism in Allium fistulosum.

    PubMed

    McNear, David H; Afton, Scott E; Caruso, Joseph A

    2012-03-01

    While continuing efforts are devoted to studying the mutually protective effect of mercury and selenium in mammals, few studies have investigated the mercury-selenium antagonism in plants. In this study, we report the metabolic fate of mercury and selenium in Allium fistulosum (green onion) after supplementation with sodium selenite and mercuric chloride. Analysis of homogenized root extracts via capillary reversed phase chromatography coupled with inductively coupled plasma mass spectrometry (capRPLC-ICP-MS) suggests the formation of a mercury-selenium containing compound. Micro-focused synchrotron X-ray fluorescence mapping of freshly excised roots show Hg sequestered on the root surface and outlining individual root cells, while Se is more evenly distributed throughout the root. There are also discrete Hg-only, Se-only regions and an overall strong correlation between Hg and Se throughout the root. Analysis of the X-ray absorption near edge structure (XANES) spectra show a "background" of methylselenocysteine within the root with discrete spots of SeO(3)(2-), Se(0) and solid HgSe on the root surface. Mercury outlining individual root cells is possibly binding to sulfhydryl groups or plasma membrane or cell wall proteins, and in some places reacting with reduced selenium in the rhizosphere to form a mercury(ii) selenide species. Together with the formation of the root-bound mercury(ii) selenide species, we also report on the formation of cinnabar (HgS) and Hg(0) in the rhizosphere. The results presented herein shed light on the intricate chemical and biological processes occurring within the rhizosphere that influence Hg and Se bioavailability and will be instrumental in predicting the fate and assisting in the remediation of these metals in the environment and informing whether or not fruit and vegetable food selection from aerial plant compartments or roots from plants grown in Hg contaminated soils, are safe for consumption.

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

    PubMed

    Rezvanfar, Mohammad Amin; Rezvanfar, Mohammad Ali; Shahverdi, Ahmad Reza; Ahmadi, Abbas; Baeeri, Maryam; Mohammadirad, Azadeh; Abdollahi, Mohammad

    2013-02-01

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

  3. Evolution of selenium utilization traits

    PubMed Central

    Romero, Héctor; Zhang, Yan; Gladyshev, Vadim N; Salinas, Gustavo

    2005-01-01

    Background The essential trace element selenium is used in a wide variety of biological processes. Selenocysteine (Sec), the 21st amino acid, is co-translationally incorporated into a restricted set of proteins. It is encoded by an UGA codon with the help of tRNASec (SelC), Sec-specific elongation factor (SelB) and a cis-acting mRNA structure (SECIS element). In addition, Sec synthase (SelA) and selenophosphate synthetase (SelD) are involved in the biosynthesis of Sec on the tRNASec. Selenium is also found in the form of 2-selenouridine, a modified base present in the wobble position of certain tRNAs, whose synthesis is catalyzed by YbbB using selenophosphate as a precursor. Results We analyzed completely sequenced genomes for occurrence of the selA, B, C, D and ybbB genes. We found that selB and selC are gene signatures for the Sec-decoding trait. However, selD is also present in organisms that do not utilize Sec, and shows association with either selA, B, C and/or ybbB. Thus, selD defines the overall selenium utilization. A global species map of Sec-decoding and 2-selenouridine synthesis traits is provided based on the presence/absence pattern of selenium-utilization genes. The phylogenies of these genes were inferred and compared to organismal phylogenies, which identified horizontal gene transfer (HGT) events involving both traits. Conclusion These results provide evidence for the ancient origin of these traits, their independent maintenance, and a highly dynamic evolutionary process that can be explained as the result of speciation, differential gene loss and HGT. The latter demonstrated that the loss of these traits is not irreversible as previously thought. PMID:16086848

  4. Distribution and bioaccumulation of selenium in aquatic microcosms

    USGS Publications Warehouse

    Besser, John M.; Huckins, James N.; Little, Edward E.; La Point, Thomas W.

    1989-01-01

    Closed-system microcosms were used to study factors affecting the fate of selenium (Se) in aquatic systems. Distribution and bioaccumulation of Se varied among sediment types and Se species. A mixture of dissolved 75Se species (selenate, selenite and selenomethionine) was sorbed more rapidly to fine-textured, highly organic pond sediments than to sandy riverine sediments. Sulfate did not affect the distribution and bioaccumulation of 75Se over the range 80–180 mg SO4 liter−1. When each Se species was labeled separately, selenomethionine was lost from the water column more rapidly than selenate or selenite. Selenium lost from the water column accumulated primarily in sediments, but volatilization was also an important pathway for loss of Se added as selenomethionine. Loss rates of dissolved Se residues were more rapid than rates reported from mesocosm and field studies, suggesting that sediment: water interactions are more important in microcosms than in larger test systems. Daphnids accumulated highest concentrations of Se, followed by periphyton and macrophytes. Selenium added as selenomethionine was bioaccumulated preferentially compared to that added as selenite or selenate. Organoselenium compounds such as selenomethione may thus contribute disproportionately to Se bioaccumulation and toxicity in aquatic organisms.

  5. Selenium adsorption to aluminum-based water treatment residuals

    SciTech Connect

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

    2009-09-02

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

  6. Selenium Enrichment of Horticultural Crops.

    PubMed

    Puccinelli, Martina; Malorgio, Fernando; Pezzarossa, Beatrice

    2017-06-04

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

  7. [Selenium sufficiency in patients with malabsorption syndrome and its optimization with selenium enriched food supplements].

    PubMed

    Shakhovskaia, A K; Gmoshinskiĭ, I V; Shirina, L I; Mazo, V K

    2003-01-01

    Selenium security was measured in 15 adult patients suffering from malabsorption syndrome, resulted from stomach and small intestine surgical resection consequences. In 7 of them (47%) marked deficiency of this essential trace element was revealed and in other 6 (40%)--suboptimal security. The indices of selenium security in observed patients markedly and significantly (p < 0.003) increased after a 3-week course of dietetic treatment including uptake of organic selenium enriched food supplement in amount equal to 90 mcg Se per day. This dietetic treatment had mild "physiologic" character that became apparent from the observation that the largest serum selenium increase was noticed in patients with largest degree of selenium insufficiency. It's concluded that there is certain testimony for selenium security correction in malabsorption patients by means of selenium enriched food supplement.

  8. Selenium and prostate cancer prevention: insights from the selenium and vitamin E cancer prevention trial (SELECT).

    PubMed

    Nicastro, Holly L; Dunn, Barbara K

    2013-04-03

    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.

  9. Effect of two antacids on the bioavailability of paracetamol.

    PubMed

    Albin, H; Demotes-Mainard, F; Vinçon, G; Bedjaoui, A; Begaud, B

    1985-01-01

    The effect of two antacids on the bioavailability of paracetamol has been investigated in 12 young healthy volunteers. Following a random cross over design, each subject swallowed, on three separate occasions, one weak apart, 500 mg paracetamol alone, or together with two different aluminium hydroxide, magnesium hydroxide preparations (Dimalan and Maalox). Plasma paracetamol levels were measured by HPLC. The bioavailability of paracetamol was not altered by either antacid, but they both delayed the time to peak plasma concentration (0.85 h; 1.43 h; 1.25 h, without antacid, with Dimalan and with Maalox respectively). The peak plasma concentration was not affected by concurrent antacid administration.

  10. Chemical measures of bioavailability/bioaccessibility of PAHs in soil: fundamentals to application.

    PubMed

    Riding, Matthew J; Doick, Kieron J; Martin, Francis L; Jones, Kevin C; Semple, Kirk T

    2013-10-15

    Risk assessment and remediation of contaminated land is inherently dependent on the contaminants present and their availability for interaction with soil biota. An ever-growing body of evidence suggests that current regulatory procedures over-estimate the 'true' fraction available to biota. Thus, a procedure that predicts the 'bioavailable fraction' would be useful for predicting 'actual' exposure limits and provide a more relevant basis for risk assessment. The aim of this paper is to address several important questions: "How should bioavailability be defined?" "What factors affect bioavailability measurement?" "To what extent have existing protocols measured bioavailability?" "What is actually measured by chemical techniques purported to determine bioavailability?" We offer two definitions (namely 'bioavailability' and 'bioaccessibility') and review commonly employed chemical extraction techniques to measure putative bioavailability. Relative advantages and disadvantages of the techniques are highlighted to elucidate underlying factors for the wide range of conclusions observed in the literature. Although the concept of bioavailability is implicit to contaminated land risk assessment and remediation, explicit reference to and use of adjustment factors is rare amongst regulatory bodies and remediators. Use of chemical determinants for bioavailability, applicable within current legislation and due consideration to inherent variability, are proposed and barriers to their implementation discussed.

  11. Selenium Distribution and Fractionation in a Managed Urban Watershed

    NASA Astrophysics Data System (ADS)

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

    2006-12-01

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

  12. Ecological aspects of plant selenium hyperaccumulation.

    PubMed

    El Mehdawi, A F; Pilon-Smits, E A H

    2012-01-01

    Hyperaccumulators are plants that accumulate toxic elements to extraordinary levels. Selenium (Se) hyperaccumulators can contain 0.1-1.5% of their dry weight as Se, levels toxic to most other organisms. In this review we summarise what is known about the ecological functions and implications of Se (hyper)accumulation by plants. Selenium promotes hyperaccumulator growth and also offers a plant several ecological advantages through negative effects on Se-sensitive partners. High tissue Se levels reduce herbivory and pathogen infection, and high-Se litter deposition can inhibit neighbouring plants. There is no evidence for a cost of hyperaccumulation in terms of reproductive functions or pollinator visitation. Hyperaccumulators offer a niche for Se-tolerant herbivores, pollinators, microbes and neighbouring plants. They may even facilitate these partners through Se enrichment: neighbouring plants with elevated Se levels enjoy enhanced growth and reduced herbivory. Through combined negative and positive effects on ecological partners, Se hyperaccumulators likely affect local plant, microbial and animal species composition and richness, favouring Se-tolerant species at different trophic levels. By locally concentrating Se and altering its chemical form, Se hyperaccumulators likely play an important role in Se entry into, and Se cycling through, seleniferous ecosystems. These findings are of significance since they provide insight into the ecological reverberations of Se hyperaccumulation, and shed light on the possible selection pressures that have led to the evolution of this fascinating phenomenon. Better ecological insight will also help in the management of seleniferous areas and the agricultural production of Se-rich crops for phytoremediation or biofortification. © 2011 German Botanical Society and The Royal Botanical Society of the Netherlands.

  13. Rapid persulfate oxidation predicts PAH bioavailability in soils and sediments

    SciTech Connect

    Cuypers, C.; Grotenhuis, T.; Joziasse, J.; Rulkens, W.

    2000-05-15

    Persulfate oxidation was validated as a method to predict polycyclic aromatic hydrocarbon (PAH) bioavailability in soils and sediments. It was demonstrated for 14 field contaminated soils and sediments that residual PAH concentrations after a short (3 h) persulfate oxidation correspond well to residual PAH concentrations after 21 days of biodegradation. Persulfate oxidation of samples that had first been subjected to biodegradation yielded only limited additional PAH oxidation. This implies that oxidation and biodegradation removed approximately the same PAH fraction. Persulfate oxidation thus provides a good and rapid method for the prediction of PAH bioavailability. Thermogravimetric analysis of oxidized and untreated samples showed that persulfate oxidation primarily affected expanded organic matter. The results indicate that this expanded organic matter contained mainly readily bioavailable PAHs.

  14. BIOSURFACES AND BIOAVAILABILITY: A NANOSCALE OVERVIEW

    EPA Science Inventory

    Environmentally, contaminant bioavailability is a key parameter in determining exposure assessment and ultimately risk assessment/risk management. Defining bioavailability requires knowledge of the contaminant spatial/temporal disposition and transportability and the thermodyna...

  15. BIOSURFACES AND BIOAVAILABILITY: A NANOSCALE OVERVIEW

    EPA Science Inventory

    Environmentally, contaminant bioavailability is a key parameter in determining exposure assessment and ultimately risk assessment/risk management. Defining bioavailability requires knowledge of the contaminant spatial/temporal disposition and transportability and the thermodyna...

  16. 21 CFR 573.920 - Selenium.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ..., AND RELATED PRODUCTS FOOD ADDITIVES PERMITTED IN FEED AND DRINKING WATER OF ANIMALS Food Additive... Act; unless the Commissioner of Food and Drugs makes a determination that: (1) Selenium additives are... food additive selenium is a nutrient administered in animal feed as sodium selenite or sodium selenate...

  17. 21 CFR 573.920 - Selenium.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ..., AND RELATED PRODUCTS FOOD ADDITIVES PERMITTED IN FEED AND DRINKING WATER OF ANIMALS Food Additive... Act; unless the Commissioner of Food and Drugs makes a determination that: (1) Selenium additives are... food additive selenium is a nutrient administered in animal feed as sodium selenite or sodium selenate...

  18. 21 CFR 573.920 - Selenium.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ..., AND RELATED PRODUCTS FOOD ADDITIVES PERMITTED IN FEED AND DRINKING WATER OF ANIMALS Food Additive... Act; unless the Commissioner of Food and Drugs makes a determination that: (1) Selenium additives are... food additive selenium is a nutrient administered in animal feed as sodium selenite or sodium selenate...

  19. 21 CFR 573.920 - Selenium.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ..., AND RELATED PRODUCTS FOOD ADDITIVES PERMITTED IN FEED AND DRINKING WATER OF ANIMALS Food Additive... Act; unless the Commissioner of Food and Drugs makes a determination that: (1) Selenium additives are... food additive selenium is a nutrient administered in animal feed as sodium selenite or sodium selenate...

  20. Selenium Compounds Activate Early Barriers of Tumorigenesis*

    PubMed Central

    Wu, Min; Kang, Mandy M.; Schoene, Norberta W.; Cheng, Wen-Hsing

    2010-01-01

    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 test this hypothesis, we treated normal and cancerous cells with a gradient concentration of sodium selenite, methylseleninic acid and methylselenocysteine for 48 h, followed by a recovery of 1–7 days. Here we show that selenium compounds at doses of ≤LD50 can induce cellular senescence, as evidenced by the expression of senescence-associated β-galactosidase and 5-bromo-2-deoxyuridine incorporation, in normal but not cancerous cells. In response to clastogens, the ataxia telangiectasia mutated (ATM) protein is rapidly activated, which in turn initiates a cascade of DNA damage response. We found that the ATM pathway is activated by the selenium compounds, and the kinase activity is required for the selenium-induced senescence response. Pretreatment of the MRC-5 non-cancerous cells with the antioxidant N-acetylcysteine or 2,2,6,6-tetramethylpiperidine-1-oxyl suppresses the selenium-induced ATM activation and senescence. Taken together, the results suggest a novel role of selenium in the activation of early tumorigenesis barriers specific in non-cancerous cells, whereby selenium induces an ATM-dependent senescence response that depends on reactive oxygen species. PMID:20157118

  1. Selenium compounds activate early barriers of tumorigenesis

    USDA-ARS?s Scientific Manuscript database

    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...

  2. Changing selenium nutritional status of Chinese residents

    USDA-ARS?s Scientific Manuscript database

    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 ...

  3. [Screening and identification of a photosynthetic bacterium reducing selenite to red elemental selenium].

    PubMed

    Wang, Dong-liang; Xiao, Min; Qian, Wei; Han, Bo

    2007-02-01

    Selenium is essential element for humans and animals but is very toxic at higher concentrations. In four inorganic states of selenate [SeO4 2- ( VI)], selenite [SeO3 2- (IV)], elemental selenium [Se (0)] and selenide [Se2- (- II )], selenite is well known to be more soluble and higher toxic than other three forms. Many microorganisms have the capacity to reduce selenite to red elemental selenium, which provide the potential to cope with the detoxification of pollution and to use the biological availability of red elemental selenium. Strain S3 that was more resistant to sodium selenite was selected from 20 photosynthetic bacteria preserved in laboratory. The red granule produced by S3 was identified as elemental selenium ( Se) by transmission electron microscopy and Electron-Dispersive X-ray (EDX) analysis. The granule diameter of the red elemental selenium was 5nm - 200nm, similar as the Nano-Se that has bioavailability. Morphology, physiology and photosynthetic pigments analysis results showed that strain S3 was essentially consistent with Rhodobacter azotoformans . The 16S rDNA sequence analysis (GenBank accession number DQ402051) suggested that strain S3 was clustered together with R. azotoformans in phylogenetic tree, with the sequence identity of 99% . Based on all the results of taxonomy, strain S3 was identified as R. azotoformans S3. The effects of selenite on growth kinetics and the ability to resistant selenite of strain S3 were investigated. In contrast to Rhodospirillum rubrum which was reported not to reduce selenite until the end of exponential growth, strain S3 transformed selenite (1.25mmol/L) at the beginning of the growth, suggesting that strain S3 and Rs. rubrum may employ different strategies to reduce selenite. Strain S3 can grow in the presence of up to 125mmol/L sodium selenite, which is much higher than those which could be resisted to by other bacteria such as Escherichia coli ( < 20mmol/L) and Ralstonia metallidurans CH34 ( < 6mmol/L) . It

  4. Aluminum bioavailability from tea infusion

    PubMed Central

    Yokel, Robert A.; Florence, Rebecca L.

    2008-01-01

    The objective was to estimate oral Al bioavailability from tea infusion in the rat, using the tracer 26Al. 26Al citrate was injected into tea leaves. An infusion was prepared from the dried leaves and given intra-gastrically to rats which received concurrent intravenous 27Al infusion. Oral Al bioavailability (F) was calculated from the area under the 26Al, compared to 27Al, serum concentration × time curves. Bioavailability from tea averaged 0.37%; not significantly different from water (F = 0.3%), or basic sodium aluminum phosphate (SALP) in cheese (F = 0.1 to 0.3%), but greater than acidic SALP in a biscuit (F = 0.1%). Time to maximum serum 26Al concentration was 1.25, 1.5, 8 and 4.8 h, respectively. These results of oral Al bioavailability × daily consumption by the human suggest tea can provide a significant amount of the Al that reaches systemic circulation. This can allow distribution to its target organs of toxicity, the central nervous, skeletal and hematopoietic systems. Further testing of the hypothesis that Al contributes to Alzheimer's disease may be more warranted with studies focusing on total average daily food intake, including tea and other foods containing appreciable Al, than drinking water. PMID:18848597

  5. Areas Susceptible to Irrigation-Induced Selenium Contamination of Water and Biota in the Western United States

    USGS Publications Warehouse

    Seiler, Ralph L.; Skorupa, Joseph P.; Peltz, Lorri A.

    1999-01-01

    The U.S. Department of the Interior (DOI) studied contamination induced by irrigation drainage in 26 areas of the Western United States during 1986-95. Comprehensive compilation, synthesis, and evaluation of the data resulting from these studies were initiated by DOI in 1992. Soils and ground water in irrigated areas of the West can contain high concentrations of selenium because of (1) residual selenium from the soil's parent rock beneath irrigated land; (2) selenium derived from rocks in mountains upland from irrigated land by erosion and transport along local drainages, and (3) selenium brought into the area in surface water imported for irrigation. Application of irrigation water to seleniferous soils can dissolve and mobilize selenium and create hydraulic gradients that cause the discharge of seleniferous ground water into irrigation drains. Given a source of selenium, the magnitude of selenium contamination in drainage-affected aquatic ecosystems is strongly related to the aridity of the area and the presence of terminal lakes and ponds. Marine sedimentary rocks and deposits of Late Cretaceous or Tertiary age are generally seleniferous in the Western United States. Depending on their origin and history, some Tertiary continental sedimentary deposits also are seleniferous. Irrigation of areas associated with these rocks and deposits can result in concentrations of selenium in water that exceed criteria for the protection of freshwater aquatic life. Geologic and climatic data for the Western United States were evaluated and incorporated into a geographic information system (GIS) to produce a map identifying areas susceptible to irrigation-induced selenium contamination. Land is considered susceptible where a geologic source of selenium is in or near the area and where the evaporation rate is more than 2.5 times the precipitation rate. In the Western United States, about 160,000 square miles of land, which includes about 4,100 square miles (2.6 million acres) of

  6. Selenium reduces mobile phone (900 MHz)-induced oxidative stress, mitochondrial function, and apoptosis in breast cancer cells.

    PubMed

    Kahya, Mehmet Cemal; Nazıroğlu, Mustafa; Çiğ, Bilal

    2014-08-01

    Exposure to mobile phone-induced electromagnetic radiation (EMR) may affect biological systems by increasing free oxygen radicals, apoptosis, and mitochondrial depolarization levels although selenium may modulate the values in cancer. The present study was designed to investigate the effects of 900 MHz radiation on the antioxidant redox system, apoptosis, and mitochondrial depolarization levels in MDA-MB-231 breast cancer cell line. Cultures of the cancer cells were divided into four main groups as controls, selenium, EMR, and EMR + selenium. In EMR groups, the cells were exposed to 900 MHz EMR for 1 h (SAR value of the EMR was 0.36 ± 0.02 W/kg). In selenium groups, the cells were also incubated with sodium selenite for 1 h before EMR exposure. Then, the following values were analyzed: (a) cell viability, (b) intracellular ROS production, (c) mitochondrial membrane depolarization, (d) cell apoptosis, and (e) caspase-3 and caspase-9 values. Selenium suppressed EMR-induced oxidative cell damage and cell viability (MTT) through a reduction of oxidative stress and restoring mitochondrial membrane potential. Additionally, selenium indicated anti-apoptotic effects, as demonstrated by plate reader analyses of apoptosis levels and caspase-3 and caspase-9 values. In conclusion, 900 MHz EMR appears to induce apoptosis effects through oxidative stress and mitochondrial depolarization although incubation of selenium seems to counteract the effects on apoptosis and oxidative stress.

  7. 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

  8. The Effect of Selenium Supplementation on Glucose Homeostasis and the Expression of Genes Related to Glucose Metabolism.

    PubMed

    Jablonska, Ewa; Reszka, Edyta; Gromadzinska, Jolanta; Wieczorek, Edyta; Krol, Magdalena B; Raimondi, Sara; Socha, Katarzyna; Borawska, Maria H; Wasowicz, Wojciech

    2016-12-13

    The aim of the study was to evaluate the effect of selenium supplementation on the expression of genes associated with glucose metabolism in humans, in order to explain the unclear relationship between selenium and the risk of diabetes. For gene expression analysis we used archival samples of cDNA from 76 non-diabetic subjects supplemented with selenium in the previous study. The supplementation period was six weeks and the daily dose of selenium was 200 µg (as selenium yeast). Blood for mRNA isolation was collected at four time points: before supplementation, after two and four weeks of supplementation, and after four weeks of washout. The analysis included 15 genes encoding selected proteins involved in insulin signaling and glucose metabolism. In addition, HbA1c and fasting plasma glucose were measured at three and four time points, respectively. Selenium supplementation was associated with a significantly decreased level of HbA1c but not fasting plasma glucose (FPG) and significant down-regulation of seven genes: INSR, ADIPOR1, LDHA, PDHA, PDHB, MYC, and HIF1AN. These results suggest that selenium may affect glycemic control at different levels of regulation, linked to insulin signaling, glycolysis, and pyruvate metabolism. Further research is needed to investigate mechanisms of such transcriptional regulation and its potential implication in direct metabolic effects.

  9. The Effect of Selenium Supplementation on Glucose Homeostasis and the Expression of Genes Related to Glucose Metabolism

    PubMed Central

    Jablonska, Ewa; Reszka, Edyta; Gromadzinska, Jolanta; Wieczorek, Edyta; Krol, Magdalena B.; Raimondi, Sara; Socha, Katarzyna; Borawska, Maria H.; Wasowicz, Wojciech

    2016-01-01

    The aim of the study was to evaluate the effect of selenium supplementation on the expression of genes associated with glucose metabolism in humans, in order to explain the unclear relationship between selenium and the risk of diabetes. For gene expression analysis we used archival samples of cDNA from 76 non-diabetic subjects supplemented with selenium in the previous study. The supplementation period was six weeks and the daily dose of selenium was 200 µg (as selenium yeast). Blood for mRNA isolation was collected at four time points: before supplementation, after two and four weeks of supplementation, and after four weeks of washout. The analysis included 15 genes encoding selected proteins involved in insulin signaling and glucose metabolism. In addition, HbA1c and fasting plasma glucose were measured at three and four time points, respectively. Selenium supplementation was associated with a significantly decreased level of HbA1c but not fasting plasma glucose (FPG) and significant down-regulation of seven genes: INSR, ADIPOR1, LDHA, PDHA, PDHB, MYC, and HIF1AN. These results suggest that selenium may affect glycemic control at different levels of regulation, linked to insulin signaling, glycolysis, and pyruvate metabolism. Further research is needed to investigate mechanisms of such transcriptional regulation and its potential implication in direct metabolic effects. PMID:27983572

  10. Drug Bioavailability Data: (Un)Available.

    ERIC Educational Resources Information Center

    Capomacchia, Anthony C.; And Others

    1979-01-01

    The obtainability of drug bioavailability data from both brand-name and generic-drug manufacturers was studied to document the relative change in availability to pharmacy students of drug bioavailability data between 1978 and 1976 for drugs exhibiting bioavailability problems. The results indicate no major change. (JMD)

  11. Drug Bioavailability Data: (Un)Available.

    ERIC Educational Resources Information Center

    Capomacchia, Anthony C.; And Others

    1979-01-01

    The obtainability of drug bioavailability data from both brand-name and generic-drug manufacturers was studied to document the relative change in availability to pharmacy students of drug bioavailability data between 1978 and 1976 for drugs exhibiting bioavailability problems. The results indicate no major change. (JMD)

  12. Selenium toxicosis in three California sea lions (Zalophus californianus).

    PubMed

    Edwards, W C; Whitenack, D L; Alexander, J W; Solangi, M A

    1989-12-01

    Selenium poisoning occurs worldwide in nearly all domestic animals. Acute selenium poisoning is associated with feeding high levels or injecting excessive amounts of selenium and is usually fatal. The acute poisoning may cause gastrointestinal disturbance, muscle weakness, depression of the central nervous system, prostration and death (1-2). Chronic selenium poisoning in cattle, sheep and horses may result from the consumption of seleniferous plants over an extended period of time. Chronic selenium results in ataxia, incoordination, partial blindness, paralysis, loss of hair or wool, abnormal hoof growth and possibly abnormal changes in behavior (1). There is little information regarding the clinical signs and pathology of selenium toxicosis in marine mammals. Likewise, there is little information regarding normal tissue levels or toxicologically significant levels of selenium in these species. The results of these investigations in sea lions, based on clinical signs, pathologic findings and tissue levels of selenium, suggest subacute or chronic selenium poisoning was most likely from dietary fish high in selenium.

  13. Evaluation of selenium in dietary supplements using elemental speciation.

    PubMed

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

    2017-03-01

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

  14. From conceptual model to remediation: bioavailability, a key to clean up heavy metal contaminated soils.

    NASA Astrophysics Data System (ADS)

    Petruzzelli, Gianniantonio; Pedron, Francesca; Pezzarossa, Beatrice

    2013-04-01

    Processes of metal bioavailability in the soil To know the bioavailability processes at site specific levels is essential to understand in detail the risks associated with pollution, and to support the decision-making process, i.e. description of the conceptual model and choice of clean up technologies. It is particularly important to assess how chemical, physical and biological processes in the soil affect the reactions leading to adsorption, precipitation or release of contaminants. The measurement of bioavailability One of the main difficulties in the practical application of the bioavailability concept in soil remediation is the lack of consensus on the method to be used to measure bioavailability. The best strategy is to apply a series of tests to assess bioavailability, since no applicable method is universally valid under all conditions. As an example, bioavailability tests for phytotechnology application should consider two distinct aspects: a physico-chemical driven solubilization process and a physiologically driven uptake process. Soil and plant characteristics strongly influence bioavailability. Bioavailability as a tool in remediation strategies Bioavailability can be used at all stages in remediation strategies: development of the conceptual model, evaluation of risk assessment, and selection of the best technology, considering different scenarios and including different environmental objectives. Two different strategies can be followed: the reduction and the increase of bioavailability. Procedures that reduce bioavailability aim to prevent the movement of pollutants from the soil to the living organisms, essentially by: i) removal of the labile phase of the contaminant, i.e. the fraction which is intrinsic to the processes of bioavailability (phytostabilization); ii) conversion of the labile fraction into a stable fraction (precipitation or adsorption); iii) increase of the resistance to mass transfer of the contaminants (inertization). Procedures

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

    PubMed Central

    2013-01-01

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

  16. 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.

  17. 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

  18. Evaluation of flushing of a high-selenium backwater channel in the Colorado River

    USGS Publications Warehouse

    Hamilton, S.J.; Holley, K.M.; Buhl, K.J.; Bullard, F.A.; Weston, L.K.; McDonald, S.F.

    2004-01-01

    Concern has been raised that selenium contamination may be adversely affecting endangered fish in the upper Colorado River basin. The objective of the study was to determine if operation of a water control structure (opened in December 1996) that allowed the Colorado River to flow through a channel area at Walter Walker State Wildlife Area (WWSWA) would reduce selenium and other inorganic elements in water, sediment, aquatic invertebrates, and forage fish. Endangered Colorado pikeminnow were collected and muscle plug samples taken for selenium analysis. Selenium concentrations in filtered water were 21.0 ??g/L in 1995, 23.5 ??g/L in 1996, 2.1 ??g/L in 1997, and 2.1 ??g/L in 1998. Selenium concentrations in sediment cores and sediment traps were 8.5 ??/g in 1995, 8.2 ??g/g in 1996, 4.8 ??g/g in 1997, and 1.1 ??g/g in 1998. Selenium concentrations in aquatic invertebrates were 27.4 ??g/g in 1996, 15.5 ??g/g in 1997, and 4.9 ??g/g in 1998. Selenium concentrations in forage fish were 27.2 ??g/g in 1996, 20.2 ??g/g in 1997, and 8.6 ??g/g in 1998. Selenium concentrations in muscle plugs of Colorado pikeminnow were 9.8 ??g/g in 1995, 9.5 ??g/g in 1996, 9.0 ??g/g in 1997, and 10.3 ??g/g in 1998. Although selenium concentrations in water, sediment, aquatic invertebrates, and forage fish decreased substantially after operation of the water control structure, a corresponding change in Colorado pikeminnow did not seem to occur. Selenium concentrations in muscle plugs decreased with increasing fish total length and weight, did not change between repeat sampling in the same year or recapture in subsequent years, and seemed to be most closely associated with the mean monthly river flow for the March-July period. ?? 2004 Wiley Periodicals, Inc.

  19. Evaluation of flushing of a high-selenium backwater channel in the Colorado River.

    PubMed

    Hamilton, Steven J; Holley, Kathy M; Buhl, Kevin J; Bullard, Fern A; Weston, L Ken; McDonald, Susan F

    2004-02-01

    Concern has been raised that selenium contamination may be adversely affecting endangered fish in the upper Colorado River basin. The objective of the study was to determine if operation of a water control structure (opened in December 1996) that allowed the Colorado River to flow through a channel area at Walter Walker State Wildlife Area (WWSWA) would reduce selenium and other inorganic elements in water, sediment, aquatic invertebrates, and forage fish. Endangered Colorado pikeminnow were collected and muscle plug samples taken for selenium analysis. Selenium concentrations in filtered water were 21.0 microg/L in 1995, 23.5 microg/L in 1996, 2.1 microg/L in 1997, and 2.1 microg/L in 1998. Selenium concentrations in sediment cores and sediment traps were 8.5 microg/g in 1995, 8.2 microg/g in 1996, 4.8 microg/g in 1997, and 1.1 microg/g in 1998. Selenium concentrations in aquatic invertebrates were 27.4 microg/g in 1996, 15.5 microg/g in 1997, and 4.9 microg/g in 1998. Selenium concentrations in forage fish were 27.2 microg/g in 1996, 20.2 microg/g in 1997, and 8.6 microg/g in 1998. Selenium concentrations in muscle plugs of Colorado pikeminnow were 9.8 microg/g in 1995, 9.5 microg/g in 1996, 9.0 microg/g in 1997, and 10.3 microg/g in 1998. Although selenium concentrations in water, sediment, aquatic invertebrates, and forage fish decreased substantially after operation of the water control structure, a corresponding change in Colorado pikeminnow did not seem to occur. Selenium concentrations in muscle plugs decreased with increasing fish total length and weight, did not change between repeat sampling in the same year or recapture in subsequent years, and seemed to be most closely associated with the mean monthly river flow for the March-July period.

  20. Influence of lifestyle on vitamin bioavailability.

    PubMed

    van den Berg, Henk; van der Gaag, Martijn; Hendriks, Henk

    2002-01-01

    In this review the effects of lifestyle factors, especially alcohol consumption, on vitamin bioavailability are summarized and discussed. Alcohol effects are clearly dose-dependent. Excessive chronic alcohol intake is generally associated with vitamin deficiency (especially folate, thiamine, and vitamin B6) due to malnutrition, malabsorption, and ethanol toxicity. Effects of moderate alcohol use are mainly explained by a lower vitamin intake. In the case of vitamin A and beta-carotene, effects on post-absorptive (lipoprotein) metabolism have been demonstrated. In one diet-controlled crossover study, alcohol consumption resulted in an increase in the plasma vitamin B6 (PLP) content, especially after beer consumption (containing vitamin B6), but also after wine and spirit consumption (not containing vitamin B6). Smoking is also associated with a lower dietary vitamin intake. In the case of vitamin C, B12, folate, and beta-carotene, evidence has been presented for effects on postabsorptive metabolism, due to smoke-induced oxidative stress and/or vitamin inactivation. For vitamin E a direct effect of smoking on absorption has been demonstrated. There is no convincing evidence that low-fat diets negatively affect fat-soluble vitamin absorption, but cholesterol-lowering compounds (diets), or unabsorbable fat substitutes, may do so. Vitamin bioavailability may be compromised from certain vegetables (particularly raw), and/or from high-fiber foods, because of limited digestion and inefficient release of vitamins from the food matrix.

  1. Relationship of selenium concentrations in blood of calves to blood selenium of the dam and supplemental selenium

    SciTech Connect

    Kincaid, R.L.; Hodgson, A.S. )

    1989-01-01

    Selenium status of dam, injected Se, and dietary Ca on calf blood Se concentrations were determined in two trials. Blood was collected from heifer calf and dam pairs at parturition. Half of the calves were injected intramuscularly with .0825 mg Se/kg body weight at birth while the other half received no Se injection. The concentration of Se in the blood of the dam had a significant effect on blood Se of calves at wk 0, 1, and 3, whereas injected Se did not significantly affect blood Se concentrations in the calf until wk 10. In a separate trial, whole blood and plasma Se were significantly correlated at birth in calves, but plasma Se was only about one-third the concentration of whole blood. The concentration of dietary Ca in the calf starter did not significantly affect blood Se, but a quadratic relationship was suggested. Plasma Zn in calves was elevated at birth and then declined with age whereas plasma inorganic P increased with age. Early postnatal concentrations of Se in blood of calves are largely a function of the dam; thus, in areas of low Se intakes, Se supplements for the dam are important.

  2. Selenium in oncology: from chemistry to clinics.

    PubMed

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

    2009-10-12

    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

  3. Production of Chlorella biomass enriched by selenium and its use in animal nutrition: a review.

    PubMed

    Doucha, Jirí; Lívanský, Karel; Kotrbácek, Václav; Zachleder, Vilém

    2009-07-01

    Feedstuffs are routinely supplemented with various selenium sources, where organic forms of Se are more bio-available and less toxic than the inorganic forms (selenites, selenates). When the algae are exposed to environmental Se in the form of selenite, they are able as other microorganisms to incorporate the element to different levels, depending on the algae species. Technology of heterotrophic fed-batch cultivation of the microalga Chlorella enriched by organically bound Se was developed, where the cultivation proceeds in fermentors on aerated and mixed nutrient solution with urea as a nitrogen and glucose as a carbon and energy source. High volumetric productivity and high cell concentrations (about 70-100 g Chlorella dry mass l(-1)) can be attained if nutrients and oxygen are adequately supplied. Addition of a small quantity of a new selenoprotein source-spray-dried Se-Chlorella biomass to the diet of farm animals had better effects on specific physiological and physical parameters of animals than selenite salt and was comparable with Se yeast added to the diet. This review introduces the importance of selenium for humans and animals, methods of Se determination, heterotrophic production of selenium-enriched Chlorella biomass in a fed-batch culture regime on organic carbon, and use of the biomass in animal nutrition.

  4. Accumulation of selenium and lack of severe effects on productivity of American dippers (Cinclus mexicanus) and spotted sandpipers (Actitis macularia).

    PubMed

    Harding, Lee E; Graham, Mark; Paton, Dale

    2005-04-01

    Selenium has been found at elevated concentrations in water, sediments, and aquatic biota in the Elk River (British Columbia, Canada) and some of its tributaries downstream of several coal mines. Selenium water concentrations in those areas exceed Canadian and British Columbia guidelines and are above levels at which adverse effects to fish and waterfowl could occur. We compared selenium concentrations in the eggs of two riverine waterbirds, American dippers and spotted sandpipers, with measures of productivity: the number of eggs laid, egg hatchability, and nestling survival. In American dippers, the mean egg selenium concentration from the exposed areas, 1.10 +/- SE 0.059 microg/g wet weight, was indistinguishable from the reference areas, 0.96 +/- SE 0.059 microg/g wet weight. For spotted sandpipers, the mean egg selenium concentration in the exposed areas, 2.2 +/- 0.5 microg/g wet weight, was significantly higher than in the reference areas, 1.2 +/- 0.14 microg/g wet weight, but less than reported thresholds for waterfowl and other shorebirds. There were no significant differences in egg hatchability between dippers in reference and exposed areas, but reduced hatchability was apparent for sandpipers in exposed locations. Despite the slightly reduced hatchability in sandpipers, overall productivity was higher than regional norms for both species; thus, selenium did not affect the number of young recruited to local populations. We did not observe teratogenic effects in either species, although none was expected at these concentrations. Despite moderately high selenium concentrations in the water, mean egg selenium concentrations were less than predicted from uptake models. We hypothesise that the relatively low uptake of selenium into the eggs of the two waterbirds in this study is likely due to their lotic environment's low biological transformation and uptake rates.

  5. Hazard assessment of selenium and other trace elements in wild larval razorback sucker from the Green River, Utah

    USGS Publications Warehouse

    Hamilton, S.J.; Muth, R.T.; Waddell, B.; May, T.W.

    2000-01-01

    Contaminant investigations of the Green River in northeastern Utah have documented selenium contamination at sites receiving irrigation drainage. The Green River provides critical habitat for four endangered fishes including the largest extant riverine population of endangered razorback sucker. Although 2175 larval razorback suckers were collected from the river between 1992 and 1996, very few juveniles have been captured within recent decades. Selenium concentrations were measured in larval razorback suckers collected from five sites in the Green River (Cliff Creek, Stewart Lake Drain, Sportsman's Drain, Greasewood Corral, and Old Charlie Wash) to assess the potential for adverse effects on recruitment of larvae to the juvenile stage and the adult population. Larvae from all sites contained mean selenium concentrations ranging from 4.3 to 5.8 ??g/g. These values were at or above the proposed toxic threshold of 4 ??g/g for adverse biological effects in fish, which was derived from several laboratory and field studies with a wide range of fish species. At two sites, Cliff Creek and Stewart Lake Drain, selenium concentrations in larvae increased over time as fish grew, whereas selenium concentrations decreased as fish grew at Sportsman's Drain. Evaluation of a 279-larvae composite analyzed for 61 elements demonstrated that selenium and, to a lesser extent, vanadium were elevated to concentrations reported to be toxic to a wide range of fish species. Elevated selenium concentrations in larval razorback suckers from the five sites suggest that selenium contamination may be widespread in the Green River, and that survival and recruitment of larvae to the juvenile stage may be limited due to adverse biological effects. Selenium contamination may be adversely affecting the reproductive success and recruitment of endangered razorback sucker.

  6. Diets high in selenium and isoflavones decrease androgen-regulated gene expression in healthy rat dorsolateral prostate

    PubMed Central

    Legg, Russell L; Tolman, Jessica R; Lovinger, Cameron T; Lephart, Edwin D; Setchell, Kenneth DR; Christensen, Merrill J

    2008-01-01

    Background High dietary intake of selenium or soybean isoflavones reduces prostate cancer risk. These components each affect androgen-regulated gene expression. The objective of this work was to determine the combined effects of selenium and isoflavones on androgen-regulated gene expression in rat prostate. Methods Male Noble rats were exposed from conception until 200 days of age to diets containing an adequate (0.33-0.45 mg/kg diet) or high (3.33-3.45 mg/kg) concentration of selenium as Se-methylselenocysteine and a low (10 mg/kg) or high (600 mg/kg) level of isoflavones in a 2 × 2 factorial design. Gene expression in the dorsolateral prostate was determined for the androgen receptor, for androgen-regulated genes, and for Akr1c9, whose product catalyzes the reduction of dihydrotestosterone to 5alpha-androstane-3alpha, 17beta-diol. Activity of hepatic glutathione peroxidise 1 and of prostatic 5alpha reductase were also assayed. Results There were no differences due to diet in activity of liver glutathione peroxidase activity. Total activity of 5alpha reductase in prostate was significantly lower (p = 0.007) in rats fed high selenium/high isoflavones than in rats consuming adequate selenium/low isoflavones. High selenium intake reduced expression of the androgen receptor, Dhcr24 (24-dehydrocholesterol reductase), and Abcc4 (ATP-binding cassette sub-family C member 4). High isoflavone intake decreased expression of Facl3 (fatty acid CoA ligase 3), Gucy1a3 (guanylate cyclase alpha 3), and Akr1c9. For Abcc4 the combination of high selenium/high isoflavones had a greater inhibitory effect than either treatment alone. The effects of selenium on gene expression were always in the direction of chemoprevention Conclusion These results suggest that combined intake of high selenium and high isoflavones may achieve a greater chemopreventive effect than either compound supplemented individually. PMID:19025659

  7. Diets high in selenium and isoflavones decrease androgen-regulated gene expression in healthy rat dorsolateral prostate.

    PubMed

    Legg, Russell L; Tolman, Jessica R; Lovinger, Cameron T; Lephart, Edwin D; Setchell, Kenneth D R; Christensen, Merrill J

    2008-11-24

    High dietary intake of selenium or soybean isoflavones reduces prostate cancer risk. These components each affect androgen-regulated gene expression. The objective of this work was to determine the combined effects of selenium and isoflavones on androgen-regulated gene expression in rat prostate. Male Noble rats were exposed from conception until 200 days of age to diets containing an adequate (0.33-0.45 mg/kg diet) or high (3.33-3.45 mg/kg) concentration of selenium as Se-methylselenocysteine and a low (10 mg/kg) or high (600 mg/kg) level of isoflavones in a 2 x 2 factorial design. Gene expression in the dorsolateral prostate was determined for the androgen receptor, for androgen-regulated genes, and for Akr1c9, whose product catalyzes the reduction of dihydrotestosterone to 5alpha-androstane-3alpha, 17beta-diol. Activity of hepatic glutathione peroxidise 1 and of prostatic 5alpha reductase were also assayed. There were no differences due to diet in activity of liver glutathione peroxidase activity. Total activity of 5alpha reductase in prostate was significantly lower (p = 0.007) in rats fed high selenium/high isoflavones than in rats consuming adequate selenium/low isoflavones. High selenium intake reduced expression of the androgen receptor, Dhcr24 (24-dehydrocholesterol reductase), and Abcc4 (ATP-binding cassette sub-family C member 4). High isoflavone intake decreased expression of Facl3 (fatty acid CoA ligase 3), Gucy1a3 (guanylate cyclase alpha 3), and Akr1c9. For Abcc4 the combination of high selenium/high isoflavones had a greater inhibitory effect than either treatment alone. The effects of selenium on gene expression were always in the direction of chemoprevention These results suggest that combined intake of high selenium and high isoflavones may achieve a greater chemopreventive effect than either compound supplemented individually.

  8. Bioavailability of the Polyphenols: Status and Controversies

    PubMed Central

    D’Archivio, Massimo; Filesi, Carmelina; Varì, Rosaria; Scazzocchio, Beatrice; Masella, Roberta

    2010-01-01

    The current interest in polyphenols has been driven primarily by epidemiological studies. However, to establish conclusive evidence for the effectiveness of dietary polyphenols in disease prevention, it is useful to better define the bioavailability of the polyphenols, so that their biological activity can be evaluated. The bioavailability appears to differ greatly among the various phenolic compounds, and the most abundant ones in our diet are not necessarily those that have the best bioavailability profile. In the present review, we focus on the factors influencing the bioavailability of the polyphenols. Moreover, a critical overview on the difficulties and the controversies of the studies on the bioavailability is discussed. PMID:20480022

  9. Selenium in aquatic biota inhabiting agricultural drains in the Salton Sea Basin, California.

    PubMed

    Saiki, Michael K; Martin, Barbara A; May, Thomas W

    2012-09-01

    Resource managers are concerned that water conservation practices in irrigated farmlands along the southern border of the Salton Sea, Imperial County, California, could increase selenium concentrations in agricultural drainwater and harm the desert pupfish (Cyprinodon macularius), a federally protected endangered species. As part of a broader attempt to address this concern, we conducted a 3-year investigation to collect baseline information on selenium concentrations in seven agricultural drains inhabited by pupfish. We collected water, sediment, selected aquatic food-chain taxa (particulate organic detritus, filamentous algae, net plankton, and midge [Chironomidae] larvae), and two poeciliid fishes (western mosquitofish Gambusia affinis and sailfin molly Poecilia latipinna) for selenium determinations. The two fish species served as ecological surrogates for pupfish, which we were not permitted to sacrifice. Dissolved selenium ranged from 0.70 to 32.8 μg/L, with selenate as the major constituent. Total selenium concentrations in other environmental matrices varied widely among drains, with one drain (Trifolium 18) exhibiting especially high concentrations in detritus, 5.98-58.0 μg Se/g; midge larvae, 12.7-50.6 μg Se/g; mosquitofish, 13.2-20.2 μg Se/g; and mollies, 12.8-30.4 μg Se/g (all tissue concentrations are based on dry weights). Although toxic thresholds for selenium in fishes from the Salton Sea are still poorly understood, available evidence suggests that ambient concentrations of this element may not be sufficiently elevated to adversely affect reproductive success and survival in selenium-tolerant poeciliids and pupfish.

  10. Selenium protects reproductive system and foetus development in a rat model of gestational lead exposure.

    PubMed

    Shen, W; Chen, J; Yin, J; Wang, S-L

    2016-01-01

    Lead is a common environmental contaminant. Lead accumulation in the body is especially dangerous for pregnant women and newborns. Selenium is a trace element which may rectify the damaging effects of lead. Here we tested potential protective effects of selenium against gestational lead exposure. Pregnant SD rats were exposed to 200 mg/L of lead acetate (given with water), with or without sodium selenite supplementation (2-8 mg/kg/day via intragastric administration). Pregnant rats not exposed to lead or selenium served as control animals. The outcomes in pregnant rats were serum lead and selenium levels, reproductive hormone (follicle-stimulating hormone, luteinizing hormone, prolactin, oestradiol, progesterone) levels, and uterine and ovarian morphological changes. The outcomes in the offspring were sex differentiation, survival rates (day 21 after birth), weight (days 0-35 after birth), weight of reproductive organs, and puberty onset (foreskin separation or vaginal opening). Selenium supplementation dose-dependently decreased serum lead levels, rectified reproductive hormone levels, and attenuated reproductive morphological changes caused by lead exposure. Lead exposure did not affect sex differentiation, but significantly (p < 0.05 vs. control animals) decreased the offspring weight on days 0-28 and the weight of their reproductive organs. Furthermore, lead exposure delayed the onset of puberty. These pathological changes were dose-dependently rectified or attenuated by selenium supplementation. Gestational lead exposure causes damages to the reproductive system of pregnant rats, and negatively modulates growth and reproductive system development of the offspring. These adverse effects are rectified or attenuated by selenium supplementation.

  11. Selenium in aquatic biota inhabiting agricultural drains in the Salton Sea Basin, California

    USGS Publications Warehouse

    Saiki, Michael K.; Martin, Barbara A.; May, Thomas W.

    2012-01-01

    Resource managers are concerned that water conservation practices in irrigated farmlands along the southern border of the Salton Sea, Imperial County, California, could increase selenium concentrations in agricultural drainwater and harm the desert pupfish (Cyprinodon macularius), a federally protected endangered species. As part of a broader attempt to address this concern, we conducted a 3-year investigation to collect baseline information on selenium concentrations in seven agricultural drains inhabited by pupfish. We collected water, sediment, selected aquatic food-chain taxa (particulate organic detritus, filamentous algae, net plankton, and midge [Chironomidae] larvae), and two poeciliid fishes (western mosquitofish Gambusia affinis and sailfin molly Poecilia latipinna) for selenium determinations. The two fish species served as ecological surrogates for pupfish, which we were not permitted to sacrifice. Dissolved selenium ranged from 0.70 to 32.8 μg/L, with selenate as the major constituent. Total selenium concentrations in other environmental matrices varied widely among drains, with one drain (Trifolium 18) exhibiting especially high concentrations in detritus, 5.98–58.0 μg Se/g; midge larvae, 12.7–50.6 μg Se/g; mosquitofish, 13.2–20.2 μg Se/g; and mollies, 12.8–30.4 μg Se/g (all tissue concentrations are based on dry weights). Although toxic thresholds for selenium in fishes from the Salton Sea are still poorly understood, available evidence suggests that ambient concentrations of this element may not be sufficiently elevated to adversely affect reproductive success and survival in selenium-tolerant poeciliids and pupfish.

  12. Selenium enrichment of broccoli: interactions between selenium and secondary plant compounds.

    PubMed

    Finley, John W; Sigrid-Keck, Anna; Robbins, Rebecca J; Hintze, Korry J

    2005-05-01

    Multiple components of broccoli, such as sulforaphane (Sf) and phenolic acids, may inhibit cancer. Additionally, broccoli can accumulate selenium (Se), and Se has been demonstrated to reduce the risk of cancer. Studies were conducted to determine whether enhancement of broccoli with Se would produce a plant with superior health benefits. Although increasing the concentration of Se in broccoli from <1.0 to >800 microg/g resulted in inhibition of colon cancer in rats, it also decreased the Sf content by >80% and inhibited production of most phenolic acids. The inclusion of Se-enriched broccoli in the diet of rats induced the activity of the selenoprotein thioredoxin reductase beyond the maximum activity induced by Se alone. These results emphasize the complex interactions of bioactive chemicals in a food; attempts to maximize one component may affect accumulation of another, and consumption of high amounts of multiple bioactive compounds may result in unexpected metabolic interactions within the body.

  13. 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.

  14. Selenium in human male reproductive organs.

    PubMed

    Oldereid, N B; Thomassen, Y; Purvis, K

    1998-08-01

    The objective of the study was to obtain information on the concentration and distribution of selenium throughout the human male reproductive tract. Material was removed at autopsy from 41 men who had died suddenly and unexpectedly. Semen samples were also provided from 184 men attending an andrology clinic for fertility investigation and from 32 healthy volunteers. Significant positive correlations in the selenium concentration were demonstrated between the different reproductive organs, the testis having the highest concentrations. No correlation was found between the concentration of selenium in the genital organs and liver, kidney or blood, suggesting that its uptake and/or biochemical activity in the reproductive organs may be controlled by similar mechanisms not shared by the other organs. No significant age-dependent changes could be detected in tissue selenium concentrations. In a group of men under fertility investigation, a significant positive correlation was obtained between seminal plasma concentrations of selenium and concentrations of spermatozoa in the same ejaculate. A significant positive correlation between concentrations of zinc and selenium in the same ejaculates indicated that selenium may arise largely from the prostate gland.

  15. In Situ Immobilization of Selenium in Sediment

    SciTech Connect

    Moore, Robert C.; Stewart, Thomas Austin

    2014-09-01

    This project focused on the use of a sorbent, carbonated apatite, to immobilize selenium in the environment. It is know that apatite will sorb selenium and based on the mechanism of sorption it is theorized that carbonated apatite will be more effective that pure apatite. Immobilization of selenium in the environment is through the use of a sorbent in a permeable reactive barrier (PRB). A PRB can be constructed by trenching and backfill with the sorbent or in the case of apatite as the sorbent formed in situ using the apatite forming solution of Moore (2003, 2004). There is very little data on selenium sorption by carbonated apatite in the literature. Therefore, in this work, the basic sorptive properties of carbonated apatite were investigated. Carbonated apatite was synthesized by a precipitation method and characterized. Batch selenium kinetic and equilibrium experiments were performed. The results indicate the carbonated apatite contained 9.4% carbonate and uptake of selenium as selenite was rapid; 5 hours for complete uptake of selenium vs. more than 100 hours for pure hydroxyapatite reported in the literature. Additionally, the carbonated apatite exhibited significantly higher distribution coefficients in equilibrium experiments than pure apatite under similar experimental conditions. The next phase of this work will be to seek additional funds to continue the research with the goal of eventually demonstrating the technology in a field application.

  16. A Review of Mercury Bioavailability in Humans and Fish

    PubMed Central

    Bradley, Mark A.; Barst, Benjamin D.; Basu, Niladri

    2017-01-01

    To estimate human exposure to methylmercury (MeHg), risk assessors often assume 95%–100% bioavailability in their models. However, recent research suggests that assuming all, or most, of the ingested mercury (Hg) is absorbed into systemic circulation may be erroneous. The objective of this paper is to review and discuss the available state of knowledge concerning the assimilation or bioavailability of Hg in fish and humans. In fish, this meant reviewing studies on assimilation efficiency, that is the difference between ingested and excreted Hg over a given period of time. In humans, this meant reviewing studies that mostly investigated bioaccessibility (digestive processes) rather than bioavailability (cumulative digestive + absorptive processes), although studies incorporating absorption for a fuller picture of bioavailability were also included where possible. The outcome of this review shows that in a variety of organisms and experimental models that Hg bioavailability and assimilation is less than 100%. Specifically, 25 studies on fish were reviewed, and assimilation efficiencies ranged from 10% to 100% for MeHg and from 2% to 51% for Hg(II). For humans, 20 studies were reviewed with bioaccessibility estimates ranging from 2% to 100% for MeHg and 0.2% to 94% for Hg(II). The overall absorption estimates ranged from 12% to 79% for MeHg and 49% to 69% for Hg(II), and were consistently less than 100%. For both fish and humans, a number of cases are discussed in which factors (e.g., Hg source, cooking methods, nutrients) are shown to affect Hg bioavailability. The summaries presented here challenge a widely-held assumption in the Hg risk assessment field, and the paper discusses possible ways forward for the field. PMID:28208586

  17. A Review of Mercury Bioavailability in Humans and Fish.

    PubMed

    Bradley, Mark A; Barst, Benjamin D; Basu, Niladri

    2017-02-10

    To estimate human exposure to methylmercury (MeHg), risk assessors often assume 95%-100% bioavailability in their models. However, recent research suggests that assuming all, or most, of the ingested mercury (Hg) is absorbed into systemic circulation may be erroneous. The objective of this paper is to review and discuss the available state of knowledge concerning the assimilation or bioavailability of Hg in fish and humans. In fish, this meant reviewing studies on assimilation efficiency, that is the difference between ingested and excreted Hg over a given period of time. In humans, this meant reviewing studies that mostly investigated bioaccessibility (digestive processes) rather than bioavailability (cumulative digestive + absorptive processes), although studies incorporating absorption for a fuller picture of bioavailability were also included where possible. The outcome of this review shows that in a variety of organisms and experimental models that Hg bioavailability and assimilation is less than 100%. Specifically, 25 studies on fish were reviewed, and assimilation efficiencies ranged from 10% to 100% for MeHg and from 2% to 51% for Hg(II). For humans, 20 studies were reviewed with bioaccessibility estimates ranging from 2% to 100% for MeHg and 0.2% to 94% for Hg(II). The overall absorption estimates ranged from 12% to 79% for MeHg and 49% to 69% for Hg(II), and were consistently less than 100%. For both fish and humans, a number of cases are discussed in which factors (e.g., Hg source, cooking methods, nutrients) are shown to affect Hg bioavailability. The summaries presented here challenge a widely-held assumption in the Hg risk assessment field, and the paper discusses possible ways forward for the field.

  18. 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.

  19. Toxicity of selenium and other elements in food organisms to razorback sucker larvae

    USGS Publications Warehouse

    Hamilton, Steven J.; Holley, Kathy M.; Buhl, Kevin J.; Bullard, Fern A.; Weston, L. Ken; McDonald, Susan F.

    2002-01-01

    Elevated selenium concentrations documented in water, sediment, and biota in irrigation drain water studies by U.S. Department of the Interior agencies and academia have raised concerns that selenium may be adversely affecting endangered fish in the upper Colorado River basin. The objective of the study was to determine the effects on endangered razorback sucker (Xyrauchen texanus) larvae from exposure to selenium and other trace elements in water and zooplankton collected from sites adjacent to the Colorado River near Grand Junction, CO. A 30-day study was initiated with 5-day-old larvae exposed in a 4×4 factor experiment with four food and four water treatments, and the biological endpoints measured were survival, growth, development, and whole-body residues of selenium. Mean selenium concentration in reference water (24-Road) was <0.7 μg/l, in reference food (brine shrimp) was 3.2 μg/g, at Horsethief was 1.6 μg/l in water and 6.0 μg/g in zooplankton, at Adobe Creek was 3.4 μg/l in water and 32 μg/g in zooplankton, and at Walter Walker was 13 μg/l in water and 52 μg/g in zooplankton. Although there were differences in concentrations of inorganic elements in water and biota among the three sites, selenium was apparently the only element elevated to concentrations of concern. Effects on survival were more prominent from dietary exposure compared to waterborne exposure. Selenium concentrations of ≥4.6 μg/g in food organisms adversely affected the survival of razorback sucker larvae. The onset of mortality in larvae exposed to food and water from Walter Walker seemed delayed compared to mortality in larvae exposed to food and water from Horsethief, which has been observed in two other studies. Elevated arsenic in one food source seemed to interact with selenium to reduce the toxic effects of selenium.

  20. Development of a FI-HG-ICP-OES solid phase preconcentration system for inorganic selenium speciation in Argentinean beverages.

    PubMed

    Escudero, Luis A; Pacheco, Pablo H; Gasquez, José A; Salonia, José A

    2015-02-15

    A preconcentration system has been developed to determine inorganic selenium species. Selenium was retained by a column filled with polyvinyl chloride (PVC) with lanthanum hydroxide co-precipitation. Speciation was achieved by selective photoreduction previous Se preconcentration. The retention pH was optimized at 10.0. Two multivariate calibrations and a central composite design were employed for optimization of the system. Sample, reagents and acid flow rates are significant variables affecting the system. Employing HG-ICP-OES as detection, the optimized system reached a detection limit of 0.03μg/L, and an enhancement factor of 14875 (25 for preconcentration system, 595 for hydride generation). To verify the method' accuracy, two certified reference materials, BCR® 414 Plankton & IRMM-804 Rice Flour, were analysed. The system was applied to inorganic selenium speciation in several Argentinean beverages to estimate their selenium contribution to diet. Copyright © 2014 Elsevier Ltd. All rights reserved.

  1. 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 hematu