Different Concentrations Of Selenium Research Articles

Selenium Accumulation Characteristics of Solanum alatum

To study the effects of different concentrations of selenium on the selenium accumulation characteristics of Solanum alatum, we used the pot experiment to study effects of different selenium concentrations (0, 5, 10, 25, 50, 75, 100 mg/kg) on the biomass and selenium content of S. alatum. The results showed that all concentrations of selenium reduced the biomass of S. alatum. The biomass of S. alatum decreased with the increase of selenium concentration. In addition, with the increase of Se concentration, the Se content of S. alatum roots and stems increased. The Se content of S. alatum leaves and shoots increased first and then decreased with the increase of Se concentration. The selenium accumulation of each part of S. alatum increased first and then decreased with the increase of selenium concentration. Selenium accumulation in S. alaum shoots and whole plants were in the ranges of 0.503-13.915 μg/plant and 1.089-18.319 μg/plant respectively under the selenium stress. In all treatments, when the concentration of selenium was 10 mg/kg, the selenium accumulation of each part of S. alatum was the highest. Therefore S. alatum is most suitable for planting at a selenium concentration of 10 mg/kg.

Study on Selenium Accumulation Characteristics of Solanum nigrum

In order to study the effects of different concentrations of selenium on the selenium accumulation characteristics of Solanum nigrum, we used the pot experiment to study the effects of different selenium concentrations (0, 5, 10, 25, 50, 75, 100 mg/kg) on the biomass and selenium content of S. nigrum. The results showed that all concentrations of selenium inhibited the biomass of S. nigrum and high concentrations of selenium inhibited the growth of S. nigrum more significantly. In addition, the biomass and selenium content of S. nigrum decreased with the increase of selenium concentration. Selenium content in S. nigrum roots, stems and leaves were in the ranges of 1.75-59.83 mg/kg, 0.91-47.83 mg/kg, and 0.38-44.50 mg/kg respectively under the selenium stress. The selenium accumulation of each part of S. nigrum increased first and then decreased with the increase of selenium concentration. In all treatments, when the concentration of selenium was 10 mg/kg, the selenium accumulation of each part of S. nigrum was the highest and the selenium accumulation of S. nigrum in shoots and whole plants reached 7.888 μg/plant and 12.893 μg/plant respectively. In a word, S. nigrum is most suitable for planting at a selenium concentration of 10 mg/kg.

Selenium Accumulation Characteristics of Perilla frutescens

Pot experiments were conducted to study the effects of different concentrations of selenium (Se) on growth and Se-rich characteristics Se of Perilla frutescens. The results showed that Se treatment had significant effect on growth and Se content. With Se concentrations increased, the biomass of P. frutescens significantly decreased. The root to shoot ratio increased firstly and then decreased, which reached the peak when Se concentration was 10 mg/kg. With Se concentrations increased, Se content increased and the difference between each treatment was extremely significant. In addition, the content of Se in leaf > root > stem. Translocation factor was on the rise as a whole, compared with control. Also, Se treatment had significant effect on the amount of Se accumulation in P. frutescens. With Se concentrations increased, the accumulation of Se showed different trends. However, as a whole, the accumulation of Se tends to increase. In addition, translocation accumulation factor showed a rising trend.

Selenium modulates MMP2 expression through the TGFβ1/Smad signalling pathway in human umbilical vein endothelial cells and rabbits following lipid disturbance

BackgroundA high-fat diet is a major risk factor for coronary heart diseases. Matrix metalloprotease (MMP) expression is changed in many cardiovascular diseases. Selenium, which is an important trace element in animals, has a close relationship with cardiovascular diseases. The TGFβ1/Smad signalling pathway is ubiquitous in diverse tissues and cells, and it is also associated with the occurrence and development of cardiovascular diseases. Therefore, in this study, we aimed to determine selenium's effect on lipid metabolism, atherosclerotic plaque formation, and MMP2 expression, as well as the underlying functional mechanism. Methods and resultsIn vivo tests: 24 male New Zealand white rabbits were randomly divided into 4 groups: regular diet, high-fat diet, high-fat diet+selenium and regular diet+selenium groups. The high-fat diet induced the lipid disturbances of rabbits at week 12. Selenium supplementation lowered total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C) and triglyceride (TG) levels (p<0.01). Selenium supplementation also suppressed MMP2 over-expression in thoracic aortas. In vitro tests: Human umbilical vein endothelial cells (HUVECs) were treated with different concentrations of selenium or ox-LDL. Ox-LDL promoted MMP2 expression by increasing TGFβ1, pSmad2, pSmad3 and Smad3 expression (p<0.01). Selenium attenuated MMP2 over-expression by regulating the TGFβ1/Smad signalling pathway. ConclusionsSelenium suppressed high-fat diet-induced MMP2 over-expression in vivo by improving lipid metabolism. In vitro, selenium attenuated MMP2 over-expression through the TGFβ1/Smad signalling pathway.

Responses and Histopathological Studies of &lt;i&gt;Clarias gariepinus&lt;/i&gt; Exposed to Selenium Toxicity

Various toxicants have been deposited into aquatic environment due to human activities, in light with this, 180 healthy Clarias gariepinus juveniles with mean weight of 7.4±0.64 g and length of 11.2±0.88 cm were exposed to different concentrations of selenium (a typical toxicant) to evaluate its behaviour and histopathological response. The fish were exposed to different concentrations (2, 3, 4, 5 and 6 mg/L) of selenium under a static bioassay for 96 hours after a range finding test and 96 hours LC 50 was determined using probit method. 10 fish per concentration was used for the bioassay in triplicates. The 96 hours lethal concentration (LC 50 ) was estimated to be 3.39 mg/L. The histological examination of the gill revealed hyperplasia and haemorrhage of the gill lamellar. The kidney showed vacuolation and blood stains while the skin demonstrated mucosal eruption. These alterations increase with increase in selenium concentration. Selenium at high concentration has shown to induce behavioural changes on fish and also alterations to organs of C gariepinus juvenile. It is therefore recommended that industries ensure the incorporation of effluents treatment plants to treat wastes before discharging into the environment.

Influence of Selenium on the Production of T-2 Toxin by Fusarium poae.

The objective of this study was to investigate the effects of selenium on the production of T-2 toxin by a Fusarium poae strain cultured in a synthetic medium containing different concentrations of selenium. The T-2 toxin contents in fermentative products were evaluated by a high performance liquid chromatography (HPLC). The results showed that the production of T-2 toxin was correlated with the concentration of selenium added to the medium. In all three treatments, the addition of 1mg/L selenium to the medium resulted in a lower toxin yield than the control (0mg/L); the yield of the toxin began to increase when selenium concentration was 10mg/L, while it decreased again at 20mg/L. In summary, T-2 toxin yield in the fermentative product was affected by the addition of selenium to the medium, and a selenium concentration of 20mg/L produced the maximum inhibitory effect of T-2 toxin yield in the fermentative product of F. poae.

Selenium Phytoaccumulation by Sunflower Plants under Hydroponic Conditions

Selenium is an essential trace element for many organisms, including humans, but it is bioaccumulative and toxic at higher than homeostatic levels. Both selenium deficiency and toxicity are problems around the world. Mines, coal-fired power plants, oil refineries, and agriculture are important examples of anthropogenic sources, generating contaminated waters, and wastewaters. For reasons of human health and ecotoxicity, selenium concentration has to be controlled in drinking-water and in wastewater, as it is a potential pollutant of water bodies. In this regard, in the present study, the ability of sunflower (Helianthus annuus L.) to tolerate and accumulate selenium was assessed in hydroponic culture as a model of rhizofiltration system. Selenium content and the chlorophyll parameters of sunflower plant treated using different concentrations of selenium in two forms of sodium selenite and sodium selenate were measured to clarify (1) the response of sunflower to selenium tolerance capacity and (2) the relationship between selenium, chlorophyll fluorescence parameters, and photosynthetic pigments contents. The results showed that selenium content in sunflower plants significantly increased by increasing added selenium levels. Furthermore, Chl a and b were not impaired after 3 weeks from selenium exposure up to 3 mg L−1 for both selenite and selenate. Moreover, sunflower plants have a high selenium tolerance capacity for hydroponic clean-up. Translocation of selenate from sunflower roots to shoots was easier comparing with selenite in concept of phytoremediation processes.

Selenium Deficiency-Induced Apoptosis of Chick Embryonic Vascular Smooth Muscle Cells and Correlations with 25 Selenoproteins.

Selenium deficiency is the major cause of exudative diathesis in chicks. Subcutaneous hemorrhage is one of the typical symptoms of the disease. However, the reason for the occurrence of blood exudation remains unknown. In the present study, the vascular smooth muscle cells (VSMCs) were isolated from 17-day-old broiler chick embryos. Cell viability, cell apoptosis, and intracellular reactive oxygen species level under different concentrations of selenium (0-0.9μM) were investigated. The mRNA expression levels of 25 selenoproteins and apoptosis-related genes (p53, CytC, Caspase-3, Caspase-8, Bcl-2, and Bax) were also measured. Selenium deficiency significantly decreased cell viability and increased cell apoptosis (p<0.05). Supplementation with selenium could alleviate these changes. In general, at all levels of selenium addition, Gpx1, Gpx3, Gpx4, SepW1, and Sep15 mRNAs were all highly expressed in VSMCs, whereas Gpx2, Dio1, SepN1, SelO, and SelPb were at lower levels. There was a high correlation between Gpx2, Gpx3, Gpx4, Dio1, Txnrd1, Txnrd2, and Txnrd3 gene expression. Additionally, Gpx3, Gpx4, Dio1, Txnrd1, Txnrd2, Txnrd3, SelS, and SelPb showed a strong negative correlation with pro-apoptotic gene Caspase-3 as well as a strong positive correlation with anti-apoptotic gene Bcl-2, especially SelI (r=0.913 and r=0.929, p<0.01). These results suggest that selenium deficiency could induce VSMC apoptosis, and several selenoproteins may be involved in the development of apoptosis. Our findings provide information on the molecular mechanism of vascular injury by selenium deficiency.

Biological synthesis of selenium and germanium nanoparticles by xylotrophic basidiomycetes

Cultivated Lentinus edodes, Pleurotus ostreatus, Ganoderma lucidum, and Grifila frondosa basidiomycetes were shown to be capable of forming nanoparticles when grown on seleniumand germanium-containing media (Na2SeO3 and GeO2, respectively). The influence of different concentrations of selenium and germanium compounds on the colony growth and biomass accumulation of mushrooms was studied under deep and solid-phase cultivation. Deep cultivation of basidiomycetes on selenium-containing media leads to the formation of Se0 nanospheres; the predominant formation inside cells was performed by L. edodes and G. frondosa, and the formation in the culture medium was performed by G. lucidum and P. ostreatus. The diameters of the nanoparticles synthesized by G. lucidum and other macromycetes were 20–50 nm and 50–320 nm, respectively. The G. frondosa basidiomycetes cultivated on germanium-containing media formed nanospheres with diameters from 50 nm to 250 nm in the culture medium. In addition, P. ostreatus accumulated a large number of germanium nanoparticles in mycelium.

The bioavailability of selenium in Saccharomyces cerevisiae

Mineral selenium (Se) is an essential nutrient of great importance to biology of human. Cultivation of Saccharomyces cerevisiae cells in molasses medium with different concentrations of selenium showed that the contents of organic selenium in the cells, increased with the increase in selenium concentration up to 2μg/ml followed by a gradual decrease after 24h of incubation. No clear inhibition effect on growth or gassing power of cells was observed at all concentrations of selenium. The bioavailability of selenium (Se) in Se-yeast was evaluated by measuring Se accumulation and glutathione peroxidase (GSH-Pxe) activity. For 6weeks, Sprague-Dawley rats experiments were subjected to a Se-yeast with a graded levels (0.9, 1.8, 3.2 and 3.6μgSe/100gBW/day). The results did not show any influence on kidney function (CK), liver function (AST, ALT, ALK, protein and albumin) and glucose in serum as well as histopathology studies. Content of Se and glutathione peroxidase (GSH-Pxe) activity in erythrocytes increased gradually with increase in supplemented Se. It could be recommended to use the selenium yeast (high quality baker’s yeast containing selenium) in baking process to control the selenium level in the final product as a source of antioxidant substance for protection from different diseases instead of using selenium drugs.

Selenium speciation in soybean by high performance liquid chromatography coupled to electrospray ionization–tandem mass spectrometry (HPLC–ESI–MS/MS)

Selenium enriched soybean was cultivated in experimental fields for 4months in which the manure-based growth medium contained different concentrations (0, 50, 100, 150, 200mg/kg) of sodium selenite. Total selenium in the soybean increased across the different concentrations of selenium used, reaching a concentration of 1118.0μg/kg at the maximum concentration of selenium used. The concentration of Se-protein in the soybean was 447.2μg/kg. The speciation of selenium in the soluble fraction of the soybean protein was determined by enzymatic hydrolysis, followed by high performance liquid chromatography coupled to electrospray ionization–tandem mass spectrometry (HPLC–ESI–MS/MS), performed under optimized parameters. Se-methyselenocysteine (Se-MeSeCys) and selenomethionine (Se-Met) were monitored by selecting the multiple reaction monitoring (MRM) mode. The results showed that inorganic selenium was absorbed by the soybean and biotransformed mainly into Se-MeSeCys. Se-MeSeCys represented 66.4% of the selenium in Se-protein, and 29.2% of the total selenium in the soybean. The result showed that HPLC–ESI–MS/MS was a sensitive and accurate method for the identification and quantification for the speciation of selenium in soybean.

Purification of selenium from thorium, uranium, radium, actinium and potassium impurities for low background measurements

Summary A technique of selenium purification from 232Th, 238U, 226,228Ra, 227Ac and 40K was developed. This technique is simple to perform and employs a minimum number of highly pure reagents (bidistilled water, nitric acid). Operations carried out during purification (elution, evaporation) practically exclude losses of the target product (chemical yields of Se &gt; 99%). A test purification of 100 g of selenium was carried out using this technique. The efficiency of this technique was confirmed by low background gamma spectrometry of the purified selenium sample. Distribution coefficients of Th, U, Ra and Ac on DOWEX 50W-×8 cation-exchange resin at different concentrations of selenium and nitric acid were experimentally determinated. Instrumental neutron activation analysis of bidistilled water, deionized water and nitric acid was performed.

The fungistatic activity of organic selenium and its application to the production of cultivated mushrooms Agaricus bisporus and Pleurotus spp.

The activity of organic selenium against pathogenic molds and its use as a potential selenium source in the production of enriched mushrooms were examined. The effect of commercial selenized yeast on mycelia growth was examined using a method with mycelia disks and a well diffusion method. For mushroom enrichment, different concentrations of selenium were added to a growth substrate. The results presented in this paper suggest that the most suitable concentration of selenized yeast that inhibits the growth of the mycopathogenic molds is 70-100 mg/kg of selenium. With the addition of this concentration to the substrate, mushroom fruit bodies will uptake a high level of selenium, about 100 ?g/g for Pleurotus spp., and 200 ?g/g for Agaricus bisporus in dry weight of the mushroom. Thereby a double effect in the cultivation of mushrooms is achieved.

Synthesis and characterization of Se doped polyaniline

Present paper reports the synthesis and electrical, morphological, thermal, structural and optical characterization of polyaniline doped with Selenium. Polyaniline was synthesized by chemical oxidation using ammonium peroxodisulphate as an oxidizing agent. This was doped with different concentrations of Selenium. DC conductivity measurements on the polymer have been carried out in the temperature range 300–450 K. The results show increase in the conductivity by three orders of magnitude after doping. Scanning Electron microscopy (SEM) has also been carried out for surface morphology studies. Thermal and structural properties are also studied by DSC and FTIR spectroscopy. DSC gives information about T g and T c. UV–Vis spectroscopy is used to study the optical properties. UV–Vis studies which reveal that the band gap decreases on increasing the concentration of dopant.

The structure functional catalytic activity of rice bran lipase in the presence of selenium and lithium

Rice bran lipase (RBL), an esterase (EC 3.1.1.3) is a versatile enzyme that catalyzes the hydrolysis of ester linkages, primarily in neutral lipids, such as triglycerides. The catalytic activity of RBL in the presence of selenium and lithium has been investigated. Lipase isolated from rice bran was treated with different concentrations of selenium and lithium ions and further subjected to activity determination, along with the kinetics of inhibition of RBL in conjunction with structure–function relationship of the enzyme. Both ions showed competitive inhibition of RBL activity in a concentration-dependent manner (1 μM to 1 mM). At 1 mM concentration of SeO2 and Li2SO4, the enzyme loses its activity by 78 and 71%, respectively. From the analysis of the kinetic data, the inhibition constant K i is found to be 4 μM for Li2SO4, and 1 μM for SeO2, respectively. Spectrofluorimeter analysis and far UV-CD data showed minor changes in the emission intensity and conformation of the RBL in the presence of these ions at the above concentration. The results suggest that both selenium and lithium specifically inhibit RBL by probably binding near to the catalytic site or distorting the geometry of the active site of the RBL triad.

Selenium Modulates Oxidative Stress-Induced Cell Apoptosis in Human Myeloid HL-60 Cells Through Regulation of Calcium Release and Caspase-3 and -9 Activities

Selenium is an essential chemopreventive antioxidant element to oxidative stress, although high concentrations of selenium induce toxic and oxidative effects on the human body. However, the mechanisms behind these effects remain elusive. We investigated toxic effects of different selenium concentrations in human promyelocytic leukemia HL-60 cells by evaluating Ca(2+) mobilization, cell viability and caspase-3 and -9 activities at different sample times. We found the toxic concentration and toxic time of H(2)O(2) as 100 microM: and 10 h on cell viability in the cells using four different concentrations of H(2)O(2) (1 microM: -1 mM: ) and six different incubation times (30 min, 1, 2, 5, 10, 24 h). Then, we found the therapeutic concentration of selenium to be 200 nM: by cells incubated in eight different concentrations of selenium (10 nM: -1 mM: ) for 1 h. We measured Ca(2+) release, cell viability and caspase-3 and -9 activities in cells incubated with high and low selenium concentrations at 30 min and 1, 2, 5, 10 and 24 h. Selenium (200 nM: ) elicited mild endoplasmic reticulum stress and mediated cell survival by modulating Ca(2+) release, the caspases and cell apoptosis, whereas selenium concentrations as high as 1 mM: induced severe endoplasmic reticulum stress and caused cell death by activating modulating Ca(2+) release, the caspases and cell apoptosis. In conclusion, these results explained the molecular mechanisms of the chemoprotective effect of different concentrations of selenium on oxidative stress-induced apoptosis.

The effect of selenium on the expression of Fas/FasL in experimental autoimmune thyroiditis rats' thyroid with adequate iodine

To study the effect of different selenium intake on the expression of apoptosis protein Fas/FasL in experimental autoimmune thyroiditis (EAT) rats' thyroid with adequate iodine. Thirty-two female lewis rats were divided stochastically into 4 groups as C group, M group, Se(+) + M group, Se(-) + M group, respectively, and pretreated with feedstuffs containing different concentrations of selenium (Se(+) + M group 2 mg/kg, C and M group 0.20 mg/kg, Se(-) + M group 0.02 mg/kg, respectively) for two weeks, and immunized the rats with porcine thyroglobulin (pTg) to establish an EAT model. The thyroid gland was sampled, embedded in mineral wax and sliced, and the expression of Fas/FasL was measured with immunohistochemistry. Both the expressions of Fas and FasL of EAT rats were significantly increased as compared with control group. The expression of Fas in rats' thyroid follicular cells with EAT was down-regulated as the increased selenium intake (optical density: 0.059 +/- 0.006), the expression of Fas of Se(+) + M group (0.036 +/- 0.004) was significantly inhibited (q = 11.591, P = 0.000), and expression of Fas was lower in the Se(+) + M group than Se(-) + M group (0.050 +/- 0.005) (q = 7.055 , P = 0.000). Effect of selenium on FasL was not identified. Increasing the intake of selenium might decrease the expression of Fas on thyroid follicular cells and restrain the development of EAT.

Effect of dietary selenium and omega-3 fatty acids on muscle composition and quality in broilers

BackgroundHuman health may be improved if dietary intakes of selenium and omega-3 fatty acids are increased. Consumption of broiler meat is increasing, and the meat content of selenium and omega-3 fatty acids are affected by the composition of broiler feed. A two-way analyses of variance was used to study the effect of feed containing omega-3 rich plant oils and selenium enriched yeast on broiler meat composition, antioxidation- and sensory parameters. Four different wheat-based dietary treatments supplemented with 5% rapeseed oil or 4% rapeseed oil plus 1% linseed oil, and either 0.50 mg selenium or 0.84 mg selenium (organic form) per kg diet was fed to newly hatched broilers for 22 days.ResultsThe different dietary treatments gave distinct different concentrations of selenium and fatty acids in thigh muscle; one percent linseed oil in the diet increased the concentration of the omega-3 fatty acids 18:3, 20:5 and 22:5, and 0.84 mg selenium per kg diet gave muscle selenium concentration at the same level as is in fish muscle (0.39 mg/kg muscle). The high selenium intake also resulted in increased concentration of the long-chain omega-3 fatty acids EPA (20:5), DPA (22:5) and DHA (22:6), thus it may be speculated if high dietary selenium might have a role in increasing the concentration of EPA, DPA and DHA in tissues after intake of plant oils contning omega-3 fatty acids.ConclusionModerate modifications of broiler feed may give a healthier broiler meat, having increased content of selenium and omega-3 fatty acids. High intakes of selenium (organic form) may increase the concentration of very long-chain omega-3 fatty acids in muscle.

Distinct effects of different concentrations of sodium selenite on apoptosis, cell cycle, and gene expression profile in acute promyeloytic leukemia-derived NB4 cells

Selenium at a low concentration has a chemopreventive role against cancer, while at a high concentration, it exerts a direct antitumor effect. However, the mechanisms remain elusive. In this article, we discovered that Na(2)SeO(3) at 20 micromol/l concentration could significantly inhibit the proliferation of NB4 cells, affect the cell cycle distribution of cell population, and induce cellular changes characteristic of apoptotic cells, while this same compound at 2 micromol/l concentration had no such effects. The mechanisms underlying these overt differences caused by treatment of different concentrations of selenium were further investigated. cDNA microarray analysis showed that after treatment by 20 micromol/l Na(2)SeO(3), 34 genes were changed in expression, while treatment by 2 micromol/l Na(2)SeO(3) resulted in the changes of 29 genes. Nine genes were regulated in both groups, among which three showed opposite changes caused by 2 and 20 micromol/l Na(2)SeO(3). The majority of regulated genes did not coincide between the two experiment groups. In conclusion, 2 and 20 micromol/l Na(2)SeO(3) could have different effects on NB4 cells, and some genes might be involved in the underlying mechanisms. Our findings could provide basis for further uncovering the molecular mechanisms of the chemopreventive and antitumor effects of selenium and, in turn, for probing the rationality of treating leukemia with selenium.

Radio-protective effects of selenium in rats

The aim of this study was to evaluate the potential radio-protective effects of different selenium supplement concentrations of 4, 8, 15 and 30 ppm in rats. Four groups of rats were administered different concentrations of selenium in drinking water for 30 days before irradiation starting from the ablactation which considered as day 0. The results showed that the sodium selenite of 4 ppm and 8 ppm enhance the 30-day survival of irradiated rats at 7 Gy (60Co source, whole body irradiation dose rate of 1 Gy . min-1) compared to the control group. The mean cumulated probability of survival of rats was 69%±6 (mean±S.E.) and 77%±6 in 4 and 8 ppm groups, respectively, versus 42%±9 for control group (P>0.001). Our data also indicated that sodium selenite with concentrations of 15 and 30 ppm had no significant reduction in mortality. The mean cumulated probability of survival of rats was 50%±12 (P=0.39) and 49%±14 (P=0.04), respectively. The toxic effects of selenium were observed at 15 ppm and 30 ppm, survivals after 30 days of selenium intake were 76% and 46%, respectively. We conclude that 4 and 8 ppm sodium selenite have a radio-protective effect. 15 and 30 ppm sodium selenite had no radio-protective effects in rats, this may be due to a synergism of toxicity and radiation effects.