Addition Of Se Research Articles

Effects of silver/selenium/chitosan doped hydroxyapatite coatings on REX-734 alloy: Morphology, antibacterial activity, and cell viability

The goal of this study was to improve the antibacterial activity and cell viability of the Rex-734 alloy in biomedical applications. Various biocomposite coatings, such as single-layer hydroxyapatite (HAp), HAp/silver(Ag), and HAp/selenium(Se)/chitosan(Chit), were applied to Rex-734 alloy at various film thicknesses. The surface coatings were characterized by scanning electron microscopy, SEM, EDX, XRD and coating thickness and hardness of surface coatings were measured. The in vitro antibacterial activities of the coated and uncoated substrates were tested against Esherichia coli JM 103 and Staphylococcus aureus ATCC29293. In vitro cell–material interactions using Saos-2 osteoblast cells were characterized by the 3-(4,5-dimethylthiazol2-yl)− 2,5-diphenyltetrazolium bromide (MTT) assay for cell viability. The post-coating sintering parameters were shown to have a significant effect on the surface morphology. When compared to single HAp and HAp/Ag coatings, Se and Chit additions to HAp powders revealed good crack-free coating surfaces. Crack-free coating morphologies were achieved with a sintering speed of 3 °C/min. While single-HA coatings had an antimicrobial efficiency of 83% against E. coli, this value increased to 94% with Ag additive and to 85% with Se additive. Similarly, Ag and Se additives improved HAp's antimicrobial efficiency against Staphylococcus aureus. Cell viability decreased in the HAp/Ag coating at 86.5% and 90.93%, but increased significantly (p < 0.05) in the HA/Se-Chit coating at 137,43% and 158.23% at the end of the first and seventh days of incubation, respectively. The addition of Ag/Se/Chit to HAp increased the viability of the Rex-734 cells. Furthermore, it was revealed that the HAp-doped Se/Chit duplex biocomposite coating groups increased bone cell viability at much higher rates than the single-layer HAp coatings.

Selenium Application Decreases the Enrichment and Human Exposure Risk of Cadmium in the Leaf of Jute (Corchorus capsularis L.) Planted in Uncontaminated Purple Soil

The effects of soil selenium (Se) application on the enrichment and human exposure risk of heavy metals in the jute (Corchorus capsularis L.) leaf have attracted extensive attention. The jute was planted with or without soil Se addition for 265 days. The jute leaf was harvested seven times during the experiment to determine the content of lead (Pb), cadmium (Cd), and Se. The results showed that the enrichment ability ranked Cd &gt; Se &gt; Pb. Cd in the jute leaf exceeded the average pollutant limit in GB2762-2017 by 1.37 times without Se application. The Se application is conducive to an increase of Se by 88.11–202.79%, contrarily reducing Cd by 35.40–38.32% and Pb by 9.58–26.57%. In general, the risk quotients (HQ) of Cd and Pb were decreased and less than 1 with Se treatment. Thus, the human exposure risk of Cd and Pb is negligible when ingesting the jute leaf via diet. It is suggested that Se can be applied to inhibit the enrichment of Cd and Pb in the jute production process to reduce the potential exposure risk of Cd and Pb to the human body and increase economic and nutritional values by raising Se levels in the jute leaf.

Impact of Se and Te addition on optical characteristics of ternary GeInSb chalcogenide films as promising materials for optoelectronic applications

The present study investigates the linear and non-linear optical characteristics of non-crystalline quaternary Ge15In5Sb5Se75 (GIS-Se) and Ge15In5Sb5Te75 (GIS-Te) chalcogenide thin films. The amorphous nature of the studied compositions was confirmed by x-ray diffraction (XRD). The values of transformation temperatures determined by differential thermal analysis (DTA), such as glass transition and crystallization temperatures, are 524.3 and 639.6 K for GIS-Se and 503.6 and 542.0 K for GIS-Te. The calculated values of glass forming ability () and thermal stability () for GIS-Se are higher than those for GIS-Te. The transmittance and reflectance spectrophotometric measurements in the UV–vis. wavelength range (400–2500 nm) are used to estimate the index of refraction and extinction coefficient The obtained values of and are found to be thickness independent in the investigated range. Tauc’s extrapolation model was used to determine both Urbach tail () and optical band gap () energies. The values of () are 0.416, 0.526 eV and () are 1.83, 1.31 eV with indirect allowed transitions for GIS-Se and GIS-Te, respectively. The optical conductivity increased as photon energy () increased, and it was enhanced in the presence of Te than Se addition. The analysis of the index of refraction () is used to evaluate the dispersion energy the high frequency dielectric constant the oscillator strength the lattice dielectric constant the ratio and the optical electronegativity which were found to be higher in GIS-Te than those in GIS-Se composition. The volume () and surface () energy loss functions were found to be increased with increasing () and the presence of Te. Furthermore, the calculated values of nonlinear optical susceptibility and nonlinear index of refraction for GIS-Se and GIS-Te are 0.195 × 10−12, 2.44 × 10−11 esu and 0.868 × 10−12, 10.19 × 10−11 esu, respectively. The detailed outcomes show that the studied film samples are suitable for various optical applications such as phase-change optical rewritable disks, optical sensors, optoelectronic devices and high-speed optical fibers.

Hybrid Halide Solid Electrolytes and Bottom-up Cell Assembly Enable High Voltage Solid-State Lithium Batteries

Interface between halide based solid electrolytes and layered transition metal oxide cathodes has been found to be electro-chemically stable due to stability of chloride compounds, in particular, at >4V range. The extent of interfacial stability is correlated with the type of cationic and anionic species in the solid electrolyte compound, a fact supported by theoretical prediction and yet, not accurately measured in composite cathode mixtures. By altering the architecture of cathode into a dense additive-free structure, we have identified differences in interfacial stability of chloride compounds which are hidden in composite cathode formats. In this work, we report the use of dense cathode to track the electrochemical evolution of interface between a hybrid halide solid electrolyte composed of chloride and fluoride species. Introducing fluoride compounds is known to be a promising method to expand the oxidation stability while the nature of such expansion is found to be related to kinetics rather than thermodynamics, we report. Furthermore, fluorination of solid electrolyte is generally accompanied with loss of ionic conductivity due to strong electronegative fluoride ions. We demonstrate a fundamental change of solid-state battery assembly from conventional electrolyte pelletizing followed by electrode placement, to a bottom-up assembly route starting with dense cathode, thin (<20µm) layer of SE and anode addition, which compensates for the suppressed conductivity of fluorinated halide solid electrolytes. Through extensive characterization, compositional optimization, and electrochemical interfacial analysis, we demonstrate stable cycling of LiCoO2/hybrid halide solid electrolyte up to 4.4V vs. Li. Our findings pave the way for expanding the voltage stability of solid electrolytes without compromising the cell performance due to ionic conductivity overpotential issues.

New horizons for selenium in animal nutrition and functional foods.

Selenium (Se), one of the indispensable nutrients for both human health and animal growth, participates in various physiological functions, such as antioxidant and immune responses and metabolism. The role of dietary Se, in its organic and inorganic forms, has been well documented in domestic animals. Furthermore, many feeding strategies for different animals have been developed to increase the Se concentration in animal products to address Se deficiency and even as a potential nutritional strategy to treat free radical-associated diseases. Nevertheless, studies on investigating the optimum addition of Se in feed, the long-term consequences of Se usage in food for animal nutrition, the mechanism of metallic Se nanoparticle (SeNP) transformation in vivo, and the nutritional effects of SeNPs on feed workers and the environment are urgently needed. Starting from the absorption and metabolism mechanism of Se, this review discusses the antioxidant role of Se in detail. Based on this characteristic, we further investigated the application of Se in animal health and described some unresolved issues and unanswered questions warranting further investigation. This review is expected to provide a theoretical reference for improving the quality of food animal meat as well as for the development of Se-based biological nutrition enhancement technology.

THE EFFECT OF SPENT MUSHROOM SUBSTRATE ENRICHED WITH SELENIUM AND ZINC ON THE YIELD AND PHOTOSYNTHETIC PARAMETERS OF LETTUCE (Lactuca sativa L.)

The aim of the study was to investigate the influence of Agaricus bisporus spent mushroom substrate (A-SMS) enriched with selenium (Se) and zinc (Zn) on the yield and photosynthetic parameters of lettuce (Lactuca sativa L. var. capitata) of the ‘Skindel’ cultivar. The growing medium for the cultivation of lettuce consisted of A-SMS (10%) and commercial peat (90%). It was further enriched with Se and Zn concentrated at five levels, i.e. 0.1, 0.2, 0.4, 0.6, and 0.8 mmol·L–1 to obtain six growing medias. Se was added to the growing medium in the form of sodium selenite and sodium selenate at a 1:1 ratio, whereas Zn was added in the form of zinc nitrate hexahydrate. Lettuce was grown under controlled conditions in growth chambers. The experiment was conducted in a randomised complete block design in three replicates. The results indicated that the A-SMS added to the growing medium increased both the yield of lettuce and its biological value by increasing the content of Se and Zn. Consumable percent recommended daily allowance and safe hazard quotient for lettuce biofortified with Se and Zn were achieved. The experiment also showed that the addition of Se + Zn did not negatively affect photosynthesis and chlorophyll fluorescence parameters, which proved that these elements did not have toxic effect on lettuce in agronomic perspective.

Selenium Alleviates Carbohydrate Metabolism and Nutrient Composition in Arsenic Stressed Rice Plants

This study reported the influence of selenium (Se) on carbohydrate composition and some related enzymes and nutrient compositions of arsenic (As) stressed rice plants. Rice plants of cultivar PR126 were grown on soil amended with As in a range of 25–100 μmol/kg with and without 0.5 or 1.0 mg/kg Se. Total soluble sugars (TSS) and reducing sugars (RS) increased in leaves of As stressed plants at the tillering and grain filling stages whereas sucrose and starch contents showed the reverse trend. Se supplementation to As stressed plants further increased TSS and RS, and enhanced sucrose phosphate synthase activity in rice leaves, thus improving sucrose content and the tolerance to As stress of the plants. Se alone or in combination with As resulted in lower As accumulation in rice husk and grains, and the highest reduction was observed in Se applied at 1.0 mg/kg compared to the corresponding As treatments alone. As may limit the accumulations of Na, Mg, K, Ca, Fe, Zn and Mn in rice grains, which are essential for humans. Binary application of different combinations of As and Se protected the plants against As and increased the mineral content in rice grains. Addition of Se in As treated soil significantly alleviated As stress by enhancing grain yields compared to the corresponding As treatment. It is concluded that Se induced amelioration of the toxic impact of As in rice either by modulating carbohydrate composition and/or nutrient uptake is one of the mechanisms to alleviate As stress in plants.

Development of Intelligent Gelatin Films Incorporated with Sappan (Caesalpinia sappan L.) Heartwood Extract.

This study aimed to develop intelligent gelatin films incorporated with sappan (Caesalpinia sappan L.) heartwood extracts (SE) and characterize their properties. The intelligent gelatin film was prepared through a casting method from gelatin (3%, w/v), glycerol (25% w/w, based on gelatin weight), and SE at various concentrations (0, 0.25, 0.50, 0.75, and 1.00%, w/v). The thickness of the developed films ranged from 43 to 63 μm. The lightness and transparency of the films decreased with the increasing concentration of SE (p < 0.05). All concentrations of gelatin films incorporated with SE exhibited great pH sensitivity, as indicated by changes in film color at different pH levels (pH 1–12). Significant decreases in tensile strength were observed at 1.00% SE film (p < 0.05). The addition of SE reduced gelatin films’ solubility and water vapor permeability (p < 0.05). The chemical and physical interactions between gelatin and SE affected the absorption peaks in FTIR spectra. SE was affected by increased total phenolic content (TPC) and antioxidant activity of the gelatin film, and the 1.00% SE film showed the highest TPC (15.60 mg GAE/g db.) and antioxidant activity (DPPH: 782.71 μM Trolox/g db. and FRAP: 329.84 mM/g db.). The gelatin films combined with SE could inhibit S. aureus and E. coli, while the inhibition zone was not observed for E. coli; it only affected the film surface area. The result suggested that gelatin films incorporated with SE can be used as an intelligent film for pH indicators and prolong the shelf life of food due to their antioxidant and antimicrobial activities.

Add-On Effect of Selenium and Vitamin D Combined Supplementation in Early Control of Graves' Disease Hyperthyroidism During Methimazole Treatment.

Prompt and stable control of hyperthyroidism is fundamental to avoid the detrimental effects of thyroid hormone excess, and antithyroid drugs, mainly methimazole (MMI), represent the first-line treatment for Graves’ disease (GD) hyperthyroidism. Decreased serum concentrations of selenium (Se) and calcifediol (25(OH)D, VitD) have been reported in newly diagnosed GD patients in observational studies. Low Se levels might exacerbate oxidative stress by compromising the antioxidant machinery’s response to reactive oxygen species, and low VitD levels might hamper the anti-inflammatory immune response. We performed a randomized controlled clinical trial (EudraCT 2017-00505011) to investigate whether Se and cholecalciferol (VitD) addition to MMI is associated with a prompter control of hyperthyroidism. Forty-two consecutive patients with newly-onset GD and marginal/insufficient Se and VitD levels were randomly assigned to treatment with either MMI monotherapy or MMI combined with Se and VitD. Se treatment was withdrawn after 180 days, while the other treatments were continued. Combination therapy resulted in a significantly greater reduction in serum FT4 concentration at 45 days (-37.9 pg/ml, CI 95%, -43.7 to -32.2 pg/ml) and 180 days (-36.5 pg/ml, CI 95%, -42 to -30.9 pg/ml) compared to MMI monotherapy (respectively: -25.7 pg/ml, CI 95%, -31.6 to -19.7 pg/ml and -22.9 pg/ml, CI 95%, -28 to -17.3 pg/ml, p 0.002). Data at 270 days confirmed this trend (-37.8 pg/ml, CI 95%, -43.6 to -32.1 pg/ml vs -24.4 pg/ml, CI 95%, -30.3 to -18.4 pg/ml). The quality of life (QoL) score was investigated by the validated “Thyroid-related Patient-Reported Outcome” questionnaire (ThyPRO). ThyPRO composite score showed a greater improvement in the intervention group at 45 days (-14.6, CI 95%, -18.8 to -10.4), 180 (-9, CI 95%, -13.9 to -4.2) and 270 days (-14.3, CI 95%, -19.5 to -9.1) compared to MMI group (respectively, -5.2, CI 95%, -9.5 to -1; -5.4, CI 95%, -10.6 to -0.2 and -3.5, CI 95%, -9 to -2.1, p 0-6 months and 6-9 months <0.05). Our results suggest that reaching optimal Se and VitD levels increases the early efficacy of MMI treatment when Se and VitD levels are suboptimal.

Effects of Selenium Supplementation on the Ion Homeostasis in the Reproductive Organs and Eggs of Laying Hens Fed With the Diet Contaminated With Cadmium, Lead, Mercury, and Chromium

The objective of this study was to explore the toxic effects of different heavy metals in combination with their deposition and ion homeostasis in the reproductive organs and eggs of laying hens, as well as the alleviating action of selenized yeast. A total of 160 Lohmann pink-shell laying hens (63-week-old) were randomly allocated into four treatments with 10 replicates of four hens each. The four dietary treatments were the corn-soybean meal basal dietary (control; CON); the CON dietary supplemented with 0.4 mg/kg selenium from selenized yeast (Se); the CON dietary supplemented with 5 mg/kg Cd + 50 mg/kg Pb +3 mg/kg Hg + 5 mg/kg Cr (HEM), and the HEM dietary supplemented with 0.4 mg/kg selenium from selenized yeast (HEM+Se). The dietary HEM significantly increased Cd, Pb, and Hg deposition in the egg yolk and ovary, and Cd and Hg deposition in the oviduct and in the follicular wall (p < 0.05). The HEM elevated Fe concentration in the egg yolk, ovary, and oviduct (p < 0.05). The HEM decreased Mn concentration in the egg yolk, Fe, Mn, and Zn concentrations in the egg white, Cu concentration in the ovary, Mg concentration in the oviduct, as well as Ca, Cu, Zn, and Mg concentrations in the follicular walls (p < 0.05). Dietary Se addition elevated Se concentration in the egg yolk, oviduct, and follicular walls and Mg concentration (p < 0.05) in the oviduct, whereas it reduced Fe concentration in the oviduct compared with the HEM-treated hens. Some positive or negative correlations among these elements were observed. Canonical Correlation Analysis showed that the concentrations of Pb and Hg in the egg yolk were positively correlated with those in the ovary. The concentration of Cd in the egg white was positively correlated with that in the oviduct. In summary, dietary Cd, Pb, Hg, and Cr in combination caused ion loss and deposition of HEM in reproductive organs of laying hens. Dietary Se addition at 0.4 mg/kg from selenized yeast alleviated the negative effects of HEM on Fe and Mg ion disorder in the oviduct and follicle wall of hens.

Selenium Antagonizes Cadmium-Induced Inflammation and Oxidative Stress via Suppressing the Interplay between NLRP3 Inflammasome and HMGB1/NF-κB Pathway in Duck Hepatocytes

Cadmium (Cd) is a toxic heavy metal that can accumulate in the liver of animals, damaging liver function. Inflammation and oxidative stress are considered primary causes of Cd-induced liver damage. Selenium (Se) is an antioxidant and can resist the detrimental impacts of Cd on the liver. To elucidate the antagonism of Se on Cd against hepatocyte injury and its mechanism, duck embryo hepatocytes were treated with Cd (4 μM) and/or Se (0.4 μM) for 24 h. Then, the hepatocyte viability, oxidative stress and inflammatory status were assessed. The findings manifested that the accumulation of reactive oxygen species (ROS) and the levels of pro-inflammatory factors were elevated in the Cd group. Simultaneously, immunofluorescence staining revealed that the interaction between NOD-like receptor pyran domain containing 3 (NLRP3) and apoptosis-associated speck-like protein (ASC) was enhanced, the movement of high-mobility group box 1 (HMGB1) from nucleus to cytoplasm was increased and the inflammatory response was further amplified. Nevertheless, the addition of Se relieved the above-mentioned effects, thereby alleviating cellular oxidative stress and inflammation. Collectively, the results suggested that Se could mitigate Cd-stimulated oxidative stress and inflammation in hepatocytes, which might be correlated with the NLRP3 inflammasome and HMGB1/nuclear factor-κB (NF-κB) signaling pathway.

Browning Development and Antioxidant Compounds in White Wines after Selenium, Iron, and Peroxide Addition

The effect of oxidation on the organoleptic properties of white wines mostly involves increased browning color, loss of the fruity aromas, and appearance of unpleasant odors. Browning, however, is known to be related with polyphenol oxidation and therefore it may be delayed by the presence of antioxidants such as selenium (Se) and SO2. On the other hand, the presence of oxidants such as metal ions and H2O2 can accelerate browning and oxidation phenomena. The browning capacity, the phenolic composition (both total and individual contents of flavanols and hydroxycinnamic acids), the antioxidant activity, and the SO2 content of Assyrtiko white wines were studied after the addition of Fe2+ and H2O2 and Se at two temperatures, employing an accelerated test. Browning was approached from a kinetic point of view, and the study was focused on the implication of oxidants and antioxidants on browning rate, paying particular attention to the content of major redox-active polyphenols, including substances with an o-diphenol feature, such as flavanols and hydroxycinnamic acids. The results showed that after the addition of oxidants it was possible to significantly accelerate the rate of browning development (up to 4.7 and six times) depending on the temperature and the concentration of the added compounds. The presence of Se protected wine color and preserved total SO2 at 35 °C, while at 50 °C, these effects were not observed. Total flavanol content decreased upon heating, while total hydroxycinnamic content showed a slight increase. Similarly, the content of the individual phenolic compounds (with the exception of caffeic acid and (+)-catechin at 35 °C) was decreased with oxidant addition, while Se addition was not adequate to prevent or even promote their oxidation.

Selenoprotein F (SELENOF)-mediated AKT1-FOXO3a-PYGL axis contributes to selenium supranutrition-induced glycogenolysis and lipogenesis

Mounting evidence showed that excess selenium (10.0–15.0-fold of adequate Se) intake caused severe hepatic lipid deposition in the vertebrate. However, the underlying mechanism remains unclear. The study was performed to elucidate the mechanism of Se supranutrition mediated-changes of lipid deposition and metabolism. We found that dietary excessive Se addition increased hepatic TGs and glucose contents, up-regulated lipogenic enzyme activities and reduced hepatic glycogen contents. Transcriptomic and immunoblotting analysis showed that Se supranutrition significantly influenced serine/threonine kinase 1 (AKT1)-forkhead box O3a (FOXO3a)-PYGL signaling and protein levels of SELENOF. Knockdown of SELENOF and PYGL by RNA interference revealed that the AKT1-FOXO3a-PYGL axis was critical for Se supranutrition-induced lipid accumulation. Moreover, Se supranutrition-induced lipid accumulation was via the increased DNA binding capacity of FOXO3a to PYGL promoter, which increased glycogenolysis, and accordingly promoted lipogenesis and lipid accumulation. Our finding provides new insight into the mechanism of Se supranutrition-induced lipid accumulation and suggests that SELENOF may be a therapeutic target for Se supranutrition induced-lipid disorders in the vertebrates.

The salicylic acid mediates selenium-induced tolerance to drought stress in tomato plants

The role of selenium (Se) in mitigating detrimental effects of drought stress on the plants has been reported, but the mechanism is still unclear. In this study, the function of Se fertilization on tomato (Solanum lycopersicum L.) under drought stress was characterized. Our results showed that the growth reduction caused by drought stress was alleviated by application of exogenous Se to a large extent. In addition, the treatment of Se significantly increased the net photosynthetic rate (Pn), transpirational rate (Tr), stomatal conductance (Gs) and water use efficiency (WUE) than in the absence of Se under drought stress treatment. Se addition also significantly inhibited the increase of malondialdehyde (MDA), soluble sugar and proline levels of tomato leaves and produced less reactive oxygen species (ROS) accumulation under drought stress. Furthermore, Se supplementation to the nutrient solution significantly increased the endogenous salicylic acid (SA) and methylated SA (MeSA) levels in tomato roots and promoted the conversion from SA to MeSA in tomato leaves under drought stress conditions via regulating the expression levels of several genes involved in SA biosynthesis and conversion such as PAL1, ICS, SAMT and SABP2. But the pretreatment with ABT (1-aminobenzotriazole, a SA inhibitor) abolished the beneficial effect of Se on drought stress tolerance of plants. These results suggested that Se application promoted photosynthetic efficiency and plant growth, alleviated drought-induced oxidative stress, and increased the endogenous SA levels, thereby imparting drought stress tolerance of tomato plants. This study may provide a theoretical basis for utilization of Se fertilizer to improve the yield and quality of agricultural products under stress.

Application of Novel Fruit Extract for Flow Assurance of Indian Field Waxy Crude Oil

Summary This research article deals with the application of shikakai fruit (Senegalia rugata) extract (SE) used as a novel bio-additive for improving flow properties of waxy crude oil (WCO) to reduce pumping cost during pipeline transportation. SE was synthesized using solvent extraction method, which is one of the most common economic extraction processes. Bio-additive was characterized by Fourier transform infrared spectroscopy (FTIR) spectroscopy, carbon, hydrogen, nitrogen, sulfur (CHNS) analysis, gas chromatography-mass gas chromatography-mass spectroscopy (GC-MS), differential light scattering, and thermogravimetric analysis (TGA). Pour point of WCO was decreased by 12°C due to addition of 1,000 ppm of SE on crude oil. Viscosity of WCO reduced significantly after addition of a bio-additive. It was found that viscosity of SE beneficiated crude oil (1,000 ppm dosage) at 30°C is less than that of pure crude at 50°C. So, addition of SE may be an alternative of heating during flow of WCO. Microscopic studies confirm that wax and other solid particles become smaller and more dispersive so that the particles are not able to come closer and form a three-dimensional network. Consequently, flow becomes easier and pumping cost gets reduced. Experimental data related to viscosity better fitted with Casson model and Bingham model before addition of SE depict that significant yield stress is required to restart the flow of crude oil. Due to the addition of SE, yield stress was deceased significantly and crude oil beneficiated with bio-additive tends to behave like a Newtonian fluid. This article also investigates wax deposition through laboratory-designed wax depositional setup. The wax deposition of crude oil after addition of 1,000 ppm SE was comparatively 56 and 75% lower than untreated crude oil when deposition studies were performed for 2 and 4 hours, respectively, at 25°C. Wax crystals of SE-treated crude oil decreased in diameter and disoriented the particles, preventing the formation of three-dimensional networks so that crude oil can easily flow through pipelines. Considering the efficacy of extracted bio-additive and its cost effectiveness, the same can be applied for flow assurance of WCO through pipelines even at very low temperatures.

Role of selenoprotein P expression in the function of pancreatic β cells: Prevention of ferroptosis-like cell death and stress-induced nascent granule degradation

Selenoprotein P (SELENOP) is a major selenium (Se)-containing protein (selenoprotein) in human plasma that is mainly synthesized in the liver. SELENOP transports Se to the cells, while SELENOP synthesized in peripheral tissues is incorporated in a paracrine/autocrine manner to maintain the levels of cellular selenoproteins, called the SELENOP cycle. Pancreatic β cells, responsible for the synthesis and secretion of insulin, are known to express SELENOP. Here, using MIN6 cells as a mouse model for pancreatic β cells and Selenop small interfering (si)RNA, we found that Selenop gene knockdown (KD) resulted in decreased cell viability, cellular pro/insulin levels, insulin secretion, and levels of several cellular selenoproteins, including glutathione peroxidase 4 (Gpx4) and selenoprotein K (Selenok). These dysfunctions induced by Selenop siRNA were recovered by the addition of Se. Ferroptosis-like cell death, regulated by Gpx4, was involved in the decrease of cell viability by Selenop KD, while stress-induced nascent granule degradation (SINGD), regulated by Selenok, was responsible for the decrease in proinsulin. SINGD was also observed in the pancreatic β cells of Selenop knockout mice. These findings indicate a significant role of SELENOP expression for the function of pancreatic β cells by maintaining the levels of cellular selenoproteins such as GPX4 and SELENOK.

Long-term vegetable production significantly reduces the selenium adsorption in two typical plastic shed soils

Long-term vegetable production in plastic shed soil (PSS) and related soil management strategies stimulate the changes of soil properties and the mobilization of selenium (Se), causing risks to environmental soil quality and human health. Nevertheless, whether the greenhouse management (defined by the years of greenhouse vegetable production) and the greenhouse type have a synergistic effect on Se mobility in PSSs subjected to long-term vegetable production is still unclear. This study investigated the joint effects of greenhouse management and the properties of PSS on Se adsorption and desorption in soils collected from solar greenhouses (SG) and round arch plastic greenhouses (PG), which has been continuously cultivated respectively for 20 and 30 years in Tongshan County, Jiangsu Province, East China. Herein, we carried out a field survey coupled with batch experiments to investigate the adsorption and desorption behavior of Se in the SG and PG soils with different years of vegetable production. Results showed that greenhouse management had differentiated effects on soil properties and Se mobility in the two typical PSSs. Compared to the open field soils, long-term vegetable production generally increased soil nutrients (i.e., total P (TP), available P (AvP)), OM and Se desorption in the SG soil, while it significantly decreased Se adsorption in both typical PSSs. The soil pH had a downward trend with the increase of the years of vegetable production. The longer years of greenhouse vegetable production, the less Se adsorption capacity occurred in PSSs with annual decrease rates of 0.48 and 0.24 mg kg−1 yr−1 for the SG and PG soil, respectively, at 1.0 mg L−1 Se addition. Conversely, the ratio of Se desorption of the SG soils increased with longer vegetable production. The results of partial least squares regression (PLSR) explained the differences in Se adsorption and desorption between the SG and PG soil due to the changes in soil properties caused by the greenhouse management and greenhouse type. The fewer Se application is therefore recommended in the SG soils than in the PG soils after long-term greenhouse vegetable production.

Selenium Accumulation and Speciation in Chickpea (Cicer arietinum) Impacted by S in Soils: Potential for Biofortification

Dietary selenium (Se) deficiency is a well-known global problem originating from food crops grown in Se-deficient soil. Agronomic Se biofortification is one of the suitable options to minimize Se deficiency. Sulfur (S) is chemically similar to Se, and the role of S on the uptake and transformation of Se in grain has not been resolved. Considering this, our study examines the influence of S on the speciation and accumulation of Se in two chickpea cultivars (Amber and PBA sheamer) grown in Se-deficient soil under glasshouse conditions. Two doses of S (0 and 14 mg kg–1) as sulfate and three doses of Se (0, 1, and 2 mg kg–1) as selenate (SeVI) were used in a randomized factorial design. The addition of SeVI increased the Se content in grain in both cultivars compared to the control treatment. Speciation of Se analysis in grain showed that most (85%) of the Se accumulated in chickpea grain in the organic forms of Se as SeCys and MeSeCys. At 2 mg/kg Se addition, the biomass and grain yield was significantly reduced (P < 0.01), while S addition tended to increase the yield. Inorganic Se was below 15%, primarily as SeVI. PBA Sheamer, a desi type and widely grown chickpea cultivar, showed the most significant proportion of organic Se species, SeCys (57%) and SeMeCys (40%). Application of S contemporarily with Se showed increased SeMeCys production in the grain of PBA Sheamer cultivar. These findings indicated that the accumulation and speciation of Se in chickpea grain was dependent on both Se and S fertilization.

Selenate regulates the activity of cell wall enzymes to influence cell wall component concentration and thereby affects the uptake and translocation of Cd in the roots of Brassica rapa L

Selenium (Se) can be used to counteract cadmium (Cd) toxicity in plants. However, mechanisms underlying the alleviation of Cd toxicity by Se have not been completely elucidated, especially those by which Se reduces Cd translocation. A hydroponic experiment was performed to illustrate the regulatory mechanisms of Cd transport by selenate (Se (VI)) in pakchoi (Brassica rapa L., LvYou 102). The results showed that this plant had a high accumulation capacity for Cd, and Se(VI) addition restricted Cd translocation from roots to shoots. Se(VI) exposure stimulated the concentrations of pectins and hemicellulose II but reduced the concentration of hemicellulose I in the roots. In many cases, the enzymes pectin methylesterase, polygalacturonase, and β-galactosidase were dose-dependently triggered by Se(VI) under Cd exposure, but root calcium concentration was significantly lowered (p < 0.05). Xyloglucan endoglycosidase (hydrolase) was triggered by Se(VI) under 2 mg L−1 Cd exposure and cellulase was generally activated by Se(VI) under Cd stress. The above results suggest that Se(VI) up-regulates pectin methylesterase activity, stimulates synthesis of pectins, and down-regulates root Ca concentration to release free carboxyl groups to combine Cd. In this study, the relationships between enzyme activity (e.g., peroxidase, superoxidase and β-galactosidase), hydrogen peroxide, cell wall structure strengthening/loosening, and Cd toxicity affected by Se(VI) were also discussed.

Nutrition by Design: Boosting Selenium Content and Fresh Matter Yields of Salad Greens With Preharvest Light Intensity and Selenium Applications.

Selenium (Se) is an essential mineral in multiple human metabolic pathways with immune modulatory effects on viral diseases including the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and HIV. Plant-based foods contain Se metabolites with unique functionalities for the human metabolism. In order to assess the value of common salad greens as Se source, we conducted a survey of lettuce commercially grown in 15 locations across the USA and Canada and found a tendency for Se to accumulate higher (up to 10 times) in lettuce grown along the Colorado river basin region, where the highest amount of annual solar radiation of the country is recorded. In the same area, we evaluated the effect of sunlight reduction on the Se content of two species of arugula [Eruca sativa (E. sativa) cv. “Astro” and Diplotaxis tenuifolia (D. tenuifolia) cv. “Sylvetta”]. A 90% light reduction during the 7 days before harvest resulted in over one-third Se decline in D. tenuifolia. The effect of light intensity on yield and Se uptake of arugula microgreens was also examined under indoor controlled conditions. This included high intensity (HI) (160 μ mol−2 s−1 for 12 h/12 h light/dark); low intensity (LI) (70 μ mol m−2 s−1 for 12 h/12 h light/dark); and HI-UVA (12 h light of 160 μ mol m−2 s−1, 2 h UVA of 40 μ mol m−2 s−1, and 10 h dark) treatments in a factorial design with 0, 1, 5, and 10 ppm Se in the growing medium. HI and HI-UVA produced D. tenuifolia plants with 25–100% higher Se content than LI, particularly with the two higher Se doses. The addition of Se produced a marked increase in fresh matter (>35% in E. sativa and >45% in D. tenuifolia). This study (i) identifies evidence to suggest the revision of food composition databases to account for large Se variability, (ii) demonstrates the potential of introducing preharvest Se to optimize microgreen yields, and (iii) provides the controlled environment industry with key information to deliver salad greens with targeted Se contents.