Selenium: Significance, and outlook for supplementation.
TL;DR: It seems advisable to pay attention to the use of this element in the manufacture of high-quality consumer goods, including finished protein-mineral preparations that enrich those diets that are deficient in selenium.
About: This article is published in Nutrition.The article was published on 2013-05-01. It has received 290 citations till now. The article focuses on the topics: Selenium in biology & Selenium.
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TL;DR: Plants can play vital role in overcoming Se deficiency and Se toxicity in different regions of the world, hence, detailed mechanism of Se metabolism inside the plants is necessary for designing effective Se phytoremediation and biofortification strategies.
Abstract: Selenium (Se) is an essential micronutrient for humans and animals, but lead to toxicity when taken in excessive amounts. Plants are the main source of dietary Se, but essentiality of Se for plants is still controversial. However, Se at low doses protects the plants from variety of abiotic stresses such as cold, drought, desiccation and metal stress. In animals, Se acts as an antioxidant and helps in reproduction, immune responses, thyroid hormone metabolism. Selenium is chemically similar to sulfur, hence taken up inside the plants via sulfur transporters present inside root plasma membrane, metabolized via sulfur assimilatory pathway, and volatilized into atmosphere. Selenium induced oxidative stress, distorted protein structure and function, are the main causes of Se toxicity in plants at high doses. Plants can play vital role in overcoming Se deficiency and Se toxicity in different regions of the world, hence, detailed mechanism of Se metabolism inside the plants is necessary for designing effective Se phytoremediation and biofortification strategies.
484 citations
Cites background from "Selenium: Significance, and outlook..."
...…is a practice of enriching the agricultural food products with certain nutrients, for example Se, to increase the dietary intake through plant breeding, genetic engineering and manipulation of agronomic practices (Zhu et al., 2009; Kieliszek and Blazejak, 2012; Borrill et al., 2014)....
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TL;DR: There are still several challenges, particularly in achieving stringent discharge limits, the long-term stability of biogenic selenium and predicting the fate of bioreduced Selenium in the environment and biotechnological advances made in the treatment ofselenium contaminated wastewaters.
321 citations
TL;DR: Selenium nanoparticles (SeNPs) represent what the authors believe to be a novel prospect for nutritional supplementation because of their lower toxicity and ability to gradually release selenium after ingestion.
315 citations
TL;DR: An overview of current knowledge on Se cycling with a specific focus on soil-plant-atmosphere interfaces is given and sources, speciation and mobility of Se in soils and plants will be discussed as well as Se hyperaccumulation by plants, biofortification and biomethylation.
Abstract: Selenium (Se) is an essential element for humans and animals, which occurs ubiquitously in the environment. It is present in trace amounts in both organic and inorganic forms in marine and freshwater systems, soils, biomass and in the atmosphere. Low Se levels in certain terrestrial environments have resulted in Se deficiency in humans, while elevated Se levels in waters and soils can be toxic and result in the death of aquatic wildlife and other animals. Human dietary Se intake is largely governed by Se concentrations in plants, which are controlled by root uptake of Se as a function of soil Se concentrations, speciation and bioavailability. In addition, plants and microorganisms can biomethylate Se, which can result in a loss of Se to the atmosphere. The mobilization of Se across soil-plant-atmosphere interfaces is thus of crucial importance for human Se status. This review gives an overview of current knowledge on Se cycling with a specific focus on soil-plant-atmosphere interfaces. Sources, speciation and mobility of Se in soils and plants will be discussed as well as Se hyperaccumulation by plants, biofortification and biomethylation. Future research on Se cycling in the environment is essential to minimize the adverse health effects associated with unsafe environmental Se levels.
311 citations
TL;DR: Current understanding in this area must be assessed to formulate appropriate treatment modalities to improve SCI recovery, and the understanding of SCI pathophysiology, interrelated or interlinked multimolecular interactions and various methods of neuronal recovery i.e., neuroprotective, immunomodulatory and neuro-regenerative pathways and relevant approaches are promoted.
Abstract: Spinal cord injury (SCI) is a destructive neurological and pathological state that causes major motor, sensory and autonomic dysfunctions. Its pathophysiology comprises acute and chronic phases and incorporates a cascade of destructive events such as ischemia, oxidative stress, inflammatory events, apoptotic pathways and locomotor dysfunctions. Many therapeutic strategies have been proposed to overcome neurodegenerative events and reduce secondary neuronal damage. Efforts have also been devoted in developing neuroprotective and neuro-regenerative therapies that promote neuronal recovery and outcome. Although varying degrees of success have been achieved, curative accomplishment is still elusive probably due to the complex healing and protective mechanisms involved. Thus, current understanding in this area must be assessed to formulate appropriate treatment modalities to improve SCI recovery. This review aims to promote the understanding of SCI pathophysiology, interrelated or interlinked multimolecular interactions and various methods of neuronal recovery i.e., neuroprotective, immunomodulatory and neuro-regenerative pathways and relevant approaches.
285 citations
Cites background from "Selenium: Significance, and outlook..."
...Vitamin A enhances the release of IL-1β, IL-6, and TNFα, improving neuroprotection [107]....
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References
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TL;DR: Selenium is needed for the proper functioning of the immune system, and appears to be a key nutrient in counteracting the development of virulence and inhibiting HIV progression to AIDS.
3,359 citations
"Selenium: Significance, and outlook..." refers background in this paper
...Biological functions of selected selenoproteins [9,13,55]...
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...These were the glycine reductase present in Clostridium sticklandii bacterium cells and formate dehydrogenase present in Clostridium thermoaceticum bacterium cells [13]....
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01 Jan 2001
TL;DR: The essential trace mineral, selenium, is of fundamental importance to human health as mentioned in this paper, and it is needed for the proper functioning of the immune system, and appears to be a key nutrient in counteracting the development of virulence and inhibiting HIV progression to AIDS.
Abstract: The essential trace mineral, selenium, is of fundamental importance to human health. As a constituent of selenoproteins, selenium has structural and enzymic roles, in the latter context being best-known as an antioxidant and catalyst for the production of active thyroid hormone. Selenium is needed for the proper functioning of the immune system, and appears to be a key nutrient in counteracting the development of virulence and inhibiting HIV progression to AIDS. It is required for sperm motility and may reduce the risk of miscarriage. Deficiency has been linked to adverse mood states. Findings have been equivocal in linking selenium to cardiovascular disease risk although other conditions involving oxidative stress and inflammation have shown benefits of a higher selenium status. An elevated selenium intake may be associated with reduced cancer risk. Large clinical trials are now planned to confirm or refute this hypothesis. In the context of these health effects, low or diminishing selenium status in some parts of the world, notably in some European countries, is giving cause for concern.
3,068 citations
TL;DR: This work identified selenoprotein genes in sequenced mammalian genomes by methods that rely on identification of selenocysteine insertion RNA structures, the coding potential of UGA codons, and the presence of cysteine-containing homologs.
Abstract: In the genetic code, UGA serves as a stop signal and a selenocysteine codon, but no computational methods for identifying its coding function are available. Consequently, most selenoprotein genes are misannotated. We identified selenoprotein genes in sequenced mammalian genomes by methods that rely on identification of selenocysteine insertion RNA structures, the coding potential of UGA codons, and the presence of cysteine-containing homologs. The human selenoproteome consists of 25 selenoproteins.
2,096 citations
"Selenium: Significance, and outlook..." refers background in this paper
...Biological functions of selected selenoproteins [9,13,55]...
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...cerevisiae yeast genes [20,56] and afterward post-translational modifications can be the explanation for the presence of SelCys [42,48,55]....
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...UGA codon identification requires the presence of SelCys, a selenocysteine insertion element, SelCys-loaded tRNA, and specific elongation factors such as EFsec and SBP2 [55]....
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TL;DR: The aulh,o~s described an incorpora t ion o f in t raper imne~ ly injee~ted '~s Se in to a IVrOtein f ract ion w N e h after partial puMfieafion showed GSH peroxidase a ctiVi:ty.
1,252 citations
Additional excerpts
...isolated glutathione peroxidase (GPx) [14]....
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TL;DR: It is found that the mRNA for this enzyme contains a UGA codon for selenocysteine which is necessary for maximal enzyme activity and explains why conversion of T4 to T3 is impaired in experimental selenium deficiency2–6 and identifies an essential role for this trace element in thyroid hormone action.
Abstract: Although thyroxine (3,5,3',5'-tetraiodothyronine, T4) is the principal secretory product of the vertebrate thyroid, its essential metabolic and developmental effects are all mediated by 3,5,3'-triiodothyronine (T3), which is produced from the prohormone by 5'-deiodination. The type-I iodothyronine deiodinase, a thiol-requiring propylthiouracil-sensitive oxidoreductase, is found mainly in liver and kidney and provides most of the circulating T3(1) but so far this enzyme has not been purified. Using expression cloning in the Xenopus oocyte, we have isolated a 2.1-kilobase complementary DNA for this deiodinase from a rat liver cDNA library. The kinetic properties of the protein expressed in transient assay systems, the tissue distribution of the messenger RNA, and its changes with thyroid status, all confirm its identity. We find that the mRNA for this enzyme contains a UGA codon for selenocysteine which is necessary for maximal enzyme activity. This explains why conversion of T4 to T3 is impaired in experimental selenium deficiency and identifies an essential role for this trace element in thyroid hormone action.
833 citations