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Selenium

About: Selenium is a research topic. Over the lifetime, 21192 publications have been published within this topic receiving 429715 citations. The topic is also known as: Se & selen.


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Journal ArticleDOI
TL;DR: Nano‐Se has a similar bioavailability in the rat and antioxidant effects on cells and is demonstrated to show less pro‐oxidative effects than selenite, as measured by cell growth.
Abstract: 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 (LD50 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.

439 citations

Journal ArticleDOI
TL;DR: It is shown that ascorbic acid can reverse some alterations caused by in vivo selenium exposure, but not ALA-D inhibition, and this study suggests that vitamin C may have a protective role in organodiselenide intoxication.
Abstract: Sodium selenite (Na2SeO3) is the selenium form used in the composition of dietary supplements, and diphenyl diselenide (PhSe)2 is an important intermediate in organic synthesis, which increases the risk of human exposure to this chemical in the workplace. These compounds have been reported to inhibit the cerebral and hepatic aminolevulinic acid dehydratase (ALA-D) in vitro, and now we show that ascorbic acid can reverse some alterations caused by in vivo selenium exposure, but not ALA-D inhibition. The effect of Na2SeO3 or (PhSe)2 and ascorbic acid on selenium distribution, total non-protein thiol, ascorbic acid content (liver and brain) and haemoglobin was also examined. Mice were exposed to 250 micromol/kg (PhSe)2, or 18.75 micromol/kg Na2SeO3 subcutaneously, and to ascorbic acid, twice a day, 1 mmol/kg intraperitonially, for 10 days. Hepatic ALA-D of mice treated with (PhSe)2 was inhibited about 58% and similar results were observed in the animals that received ascorbic acid supplementation (P 0.10). Ascorbic acid treatment decreased significantly the hepatic and cerebral deposition of Se in (PhSe)2-exposed mice (P<0.01). Hepatic non-protein thiol content was not changed by treatment with (PhSe)2, ascorbic acid or (PhSe)2+ascorbic acid. Hepatic content of ascorbic acid was twice that in mice that received (PhSe)2, independent of ascorbic acid treatment (P<0.001). The results of this study suggest that vitamin C may have a protective role in organodiselenide intoxication.

427 citations

Journal ArticleDOI
TL;DR: The results suggest that Se-P from liver provides selenium to several tissues, especially testis and brain, and indicate that transport forms of seenium other than Se-p exist because selenia levels of all tissues except testis responded to increases of dietary selenIUM in Sepp −/− mice.

425 citations

Journal ArticleDOI
TL;DR: Large differences in the optical properties (UV-visible absorption and Raman spectra) of purified extracellular nanospheres produced in this manner by the three different bacterial species differed substantially from those of amorphous Se(0) formed by chemical oxidation of H2Se and of black, vitreous Se(*) formed chemically by reduction of selenite with ascorbate.
Abstract: Certain anaerobic bacteria respire toxic selenium oxyanions and in doing so produce extracellular accumulations of elemental selenium [Se(0)]. We examined three physiologically and phylogenetically diverse species of selenate- and selenite-respiring bacteria, Sulfurospirillum barnesii, Bacillus selenitireducens, and Selenihalanaerobacter shriftii, for the occurrence of this phenomenon. When grown with selenium oxyanions as the electron acceptor, all of these organisms formed extracellular granules consisting of stable, uniform nanospheres (diameter, approximately 300 nm) of Se(0) having monoclinic crystalline structures. Intracellular packets of Se(0) were also noted. The number of intracellular Se(0) packets could be reduced by first growing cells with nitrate as the electron acceptor and then adding selenite ions to washed suspensions of the nitrate-grown cells. This resulted in the formation of primarily extracellular Se nanospheres. After harvesting and cleansing of cellular debris, we observed large differences in the optical properties (UV-visible absorption and Raman spectra) of purified extracellular nanospheres produced in this manner by the three different bacterial species. The spectral properties in turn differed substantially from those of amorphous Se(0) formed by chemical oxidation of H(2)Se and of black, vitreous Se(0) formed chemically by reduction of selenite with ascorbate. The microbial synthesis of Se(0) nanospheres results in unique, complex, compacted nanostructural arrangements of Se atoms. These arrangements probably reflect a diversity of enzymes involved in the dissimilatory reduction that are subtly different in different microbes. Remarkably, these conditions cannot be achieved by current methods of chemical synthesis.

421 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20231,062
20222,045
2021554
2020569
2019705
2018792