Effects of fecal microbiota transplantation combined with selenium on intestinal microbiota in mice with colorectal cancer.

Colorectal cancer (CRC) is the third most common cancer in the world. With the development of high-throughput gene sequencing technology, homeostasis imbalance of the intestinal microbiota has been proven to play a key role in the pathogenesis of CRC. Furthermore, fecal bacteria transplantation (FMT) has been shown to alter the intestinal microecology, and is potentially an effective treatment for CRC. Sodium selenite plays an important role in anticancer adjuvant therapy due to its high pro-oxidation characteristics. In this study, a murine CRC tumor model was induced by AOM/DSS, and CRC mice were treated by FMT, sodium selenite, and FMT combined with sodium selenite. The results showed that FMT, sodium selenite, and FMT combined with sodium selenite inhibited the occurrence of CRC in mice, increased the abundance of beneficial intestinal bacteria, produced different microorganisms, and changed the metabolic pathways of the intestinal microbiota. In summary, FMT, sodium selenite, and FMT combined with sodium selenite can inhibit the occurrence of CRC by increasing the abundance of beneficial bacteria and regulating phenotypes and metabolic pathways. Notably, the effect of FMT combined with sodium selenite in reducing the number of tumors, protecting intestinal tissues, and restoring the diversity and richness of the intestinal microbiota is superior to that of FMT alone or sodium selenite alone. The results of this study provide new ideas for the application of FMT and selenium in the treatment of CRC.

Optimization of fermentation parameters to improve the biosynthesis of selenium nanoparticles by Bacillus licheniformis F1 and its comprehensive application.

BACKGROUND: Selenium nanoparticles (SeNPs) are increasingly gaining attention due to its characteristics of low toxicity, high activity, and stability. Additionally, Bacillus licheniformis, as a probiotic, has achieved remarkable research outcomes in diverse fields such as medicine, feed processing, and pesticides, attracting widespread attention. Consequently, evaluating the activity of probiotics and SeNPs is paramount. The utilization of probiotics to synthesize SeNPs, achieving large-scale industrialization, is a current hotspot in the field of SeNPs synthesis and is currently the most promising synthetic method. To minimize production costs and maximize yield of SeNPs, this study selected agricultural by-products that are nutrient-rich, cost-effective, and readily available as culture medium components. This approach not only fulfills industrial production requirements but also mitigates the impact on downstream processes. RESULTS: The experimental findings revealed that SeNPs synthesized by B. licheniformis F1 exhibited a spherical morphology with diameters ranging from 110 to 170 nm and demonstrating high stability. Both the secondary metabolites of B. licheniformis F1 and the synthesized SeNPs possessed significant free radical scavenging ability. To provide a more robust foundation for acquiring large quantities of SeNPs via fermentation with B. licheniformis F1, key factors were identified through single-factor experiments and response surface methodology (RSM) include a 2% seed liquid inoculum, a temperature of 37 ℃, and agitation at 180 rpm. Additionally, critical factors during the optimization process were corn powder (11.18 g/L), soybean meal (10.34 g/L), and NaCl (10.68 g/L). Upon validating the optimized conditions and culture medium, B. licheniformis F1 can synthesize nearly 100.00% SeNPs from 5 mmol/L sodium selenite. Subsequently, pilot-scale verification in a 5 L fermentor using the optimized medium resulted in a shortened fermentation time, significantly reducing production costs. CONCLUSION: In this study, the efficient production of SeNPs by the probiotic B. licheniformis F1 was successfully achieved, leading to a significant reduction in fermentation costs. The exploration of the practical applications of this strain holds significant potential and provides valuable guidance for facilitating the industrial-scale implementation of microbial synthesis of SeNPs.

Selenium speciation studies in cancer patients to evaluate the responses of biomarkers of selenium status to different selenium compounds.

This work presents the first systematic comparison of selenium (Se) speciation in plasma from cancer patients treated orally with three Se compounds (sodium selenite, SS; L-selenomethionine, SeMet; or Se-methylselenocysteine, MSC) at 400 µg/day for 28 days. The primary goal was to investigate how these chemical forms of Se affect the plasma Se distribution, aiming to identify the most effective Se compound for optimal selenoprotein expression. This was achieved using methodology based on HPLC-ICP-MS after sample preparation/fractionation approaches. Measurements of total Se in plasma samples collected before and after 4 weeks of treatment showed that median total Se levels increased significantly from 89.6 to 126.4 µg kg-1 Se (p < 0.001), particularly when SeMet was administered (190.4 µg kg-1 Se). Speciation studies showed that the most critical differences between treated and baseline samples were seen for selenoprotein P (SELENOP) and selenoalbumin after administration with MSC (p = 5.8 × 10-4) and SeMet (p = 6.8 × 10-5), respectively. Notably, selenosugar-1 was detected in all low-molecular-weight plasma fractions following treatment, particularly with MSC. Two different chromatographic approaches and spiking experiments demonstrated that about 45% of that increase in SELENOP levels (to ~ 8.8 mg L-1) with SeMet is likely due to the non-specific incorporation of SeMet into the SELENOP affinity fraction. To the authors' knowledge, this has not been reported to date. Therefore, SELENOP is probably part of both the regulated (55%) and non-regulated (45%) Se pools after SeMet administration, whereas SS and MSC mainly contribute to the regulated one.

Sodium selenite attenuates inflammatory response and oxidative stress injury by regulating the Nrf2/ARE pathway in contrast-induced acute kidney injury in rats.

BACKGROUND: Contrast-induced acute kidney injury (CI-AKI) is an acute renal complication that occurs after intravascular contrast agent administration. Sodium selenite (SS) is an inorganic source of Se and has potent antioxidant properties. This study intends to examine its anti-inflammatory and antioxidant effects in CI-AKI. METHODS: A rat CI-AKI model was established with the pretreatment of SS (0.35 mg/kg). Hematoxylin-eosin staining was employed for histopathological analysis of rat kidney specimens. Biochemical analysis was conducted for renal function detection. Tissue levels of oxidative stress-related markers were estimated. Reverse transcription-quantitative polymerase chain reaction revealed the mRNA levels of proinflammatory cytokines. Western blotting showed the Nrf2 signaling-related protein expression in the rat kidney. RESULTS: SS administration alleviated the renal pathological changes and reduced the serum levels of serum creatinine, blood urea nitrogen, neutrophil gelatinase-associated lipocalin, cystatin C, and urinary level of kidney injury molecule-1 in CI-AKI rats. SS attenuated oxidative stress and inflammatory response in CI-AKI rat kidney tissues. SS activated the Nrf2 signaling transduction in the renal tissues of rats with CI-AKI. CONCLUSION: SS ameliorates CI-AKI in rats by reducing oxidative stress and inflammation via the Nrf2 signaling.

Investigation of the protective effects of different forms of selenium in freezing dog semen: Comparison of nanoparticle selenium and sodium selenite.

This study aimed to investigate the protective effects of nanoparticle selenium (SeNP) and sodium selenite (SS) on preventing oxidative stress during the freezing process of dog semen. A total of six dogs were used in the study. The ejaculate was collected from dogs three times at different times by massage method. A total of 18 ejaculates were used and each ejaculate was divided in five experimental groups. The experimental groups were designed to tris extender containing no antioxidants control, 1 µg/mL SeNP1, 2 µg/mL SeNP2, and 1 µg/mL SS1 and 2 µg/mL SS2. Extended semen were equilibrated for 1 h at 4°C, then frozen in liquid nitrogen vapour and stored in liquid nitrogen (~-196°C). After thawing, semen samples were evaluated in terms of CASA motility and kinematic parameters, spermatozoa plasma membrane integrity and viability (HE Test), spermatozoa morphology (SpermBlue) and DNA fragmentation (GoldCyto). Antioxidant enzyme activity (glutathione peroxidase; GPX, superoxide dismutase; SOD, catalase; CAT) and lipid peroxidation (malondialdehyde; MDA) were evaluated in frozen-thawed dog sperm. When the results were evaluated statistically, the progressive motility, VCL, and VAP kinematic parameters in the SeNP1 group were significantly higher than the control group after thawing (p < .05). The highest ratio of plasma membrane integrity and viable spermatozoa was observed in the SeNP1 group, but there was no statistical difference found between the groups (p > .05). Although the ratio of total morphological abnormality was observed to be lower in all groups to which different selenium forms were added, compared to the control group, no statistical difference was found. Spermatozoa tail abnormality was significantly lower in the SeNP1 group than in the control and SS2 group (p < .05). The lowest ratio of fragmented DNA was observed in the SeNP1 group, but there was no statistical difference was found between the groups (p > .05). Although there was no statistical difference between the groups in the evaluation of sperm antioxidant profile, the highest GPX, SOD and CAT values and the lowest lipid peroxidation values were obtained in the SeNP1 group. As a result, it was determined that 1 µg/mL dose of SeNP added to the tris-based extender in dog semen was beneficial on spermatological parameters, especially sperm kinematic properties and sperm morphology, and therefore nanoparticle selenium, a nanotechnology product, made a significant contribution to the freezing of dog semen.

Effects of Foliar Dressing with Chemical Nano-Selenum and Na2SeO3 on the Antioxidant System and Accumulation of Se and Bioactive Components in Cyclocarya paliurus (Sweet Tea Tree).

Selenium (Se)-rich Cyclocarya paliurus is popular for its bioactive components, and exogenous Se fortification is the most effective means of enrichment. However, the effects of exogenous Se fortification on the nutritional quality of C. paliurus are not well known. To investigate the nutrient contents and antioxidant properties of C. paliurus following Se treatment, we used a foliar spray to apply Se in two forms-chemical nano-Se (Che-SeNPs) and sodium selenite (Na2SeO3). Sampling began 10 days after spraying and was conducted every 5 days until day 30. The Se, secondary metabolite, malondialdehyde contents, antioxidant enzyme activity, Se speciation, and Se-metabolism-related gene expression patterns were analyzed in the collected samples. Exogenous Se enhancement effectively increased the Se content of leaves, reaching a maximum on days 10 and 15 of sampling, while the contents of flavonoids, triterpenes, and polyphenols increased significantly during the same period. In addition, the application of Se significantly enhanced total antioxidant activity, especially the activity of the antioxidant enzyme peroxidase. Furthermore, a positive correlation between the alleviation of lipid peroxidation and Se content was observed, while methylselenocysteine formation was an effective means of alleviating Se stress. Finally, Na2SeO3 exhibited better absorption and conversion efficiency than Che-SeNPs in C. paliurus.

Effect of Different Selenium Species on Indole-3-Acetic Acid Activity of Selenium Nanoparticles Producing Strain Bacillus altitudinis LH18.

Acting as a growth regulator, Indole-3-acetic acid (IAA) is an important phytohormone that can be produced by several Bacillus species. However, few studies have been published on the comprehensive evaluation of the strains for practical applications and the effects of selenium species on their IAA-producing ability. The present study showed the selenite reduction strain Bacillus altitudinis LH18, which is capable of producing selenium nanoparticles (SeNPs) at a high yield in a cost-effective manner. Bio-SeNPs were systematically characterized by using DLS, zeta potential, SEM, and FTIR. The results showed that these bio-SeNPs were small in particle size, homogeneously dispersed, and highly stable. Significantly, the IAA-producing ability of strain was differently affected under different selenium species. The addition of SeNPs and sodium selenite resulted in IAA contents of 221.7 µg/mL and 91.01 µg/mL, respectively, which were 3.23 and 1.33 times higher than that of the control. This study is the first to examine the influence of various selenium species on the IAA-producing capacity of Bacillus spp., providing a theoretical foundation for the enhancement of the IAA-production potential of microorganisms.

Co-metabolism of Na+/K+ ion regulated physiological enhancement on selenium-accumulation in Saccharomyces yeasts.

BACKGROUND: Selenium is an important nutritional supplement that mainly exists naturally in soil as inorganic selenium. Saccharomyces cerevisiae cells are excellent medium for converting inorganic selenium in nature into organic selenium. RESULTS: Under the co-stimulation of sodium selenite (Na2SeO3) and potassium selenite (K2SeO3), the activity of selenophosphate synthetase (SPS) was improved up to about five folds more than conventional Na2SeO3 group with the total selenite salts content of 30 mg/L. Transcriptome analysis first revealed that due to the sharing pathway between sodium ion (Na+) and potassium ion (K+), the K+ largely regulates the metabolisms of amino acid and glutathione under the accumulation of selenite salt. Furthermore, K+ could improve the tolerance performance and selenium-biotransformation yields of Saccharomyces cerevisiae cells under Na2SeO3 salt stimulation. CONCLUSION: The important role of K+ in regulating the intracellular selenium accumulation especially in terms of amino acid metabolism and glutathione, suggested a new direction for the development of selenium-enrichment supplements with Saccharomyces cerevisiae cell factory. © 2024 Society of Chemical Industry.

Selenoprotein-P1 (SEPP1) Expression in Human Proximal Tubule Cells after Ischemia-Reperfusion Injury: An In Vitro Model.

Background and Objectives: Selenium deficiency represents a risk factor for the occurrence of severe diseases, such as acute kidney injury (AKI). Recently, selenoprotein-p1 (SEPP1), a selenium transporter, mainly released by the liver, has emerged as a promising plasmatic biomarker of AKI as a consequence of cardio-surgery operations. The aim of the present study was to investigate, on an in vitro model of hypoxia induced in renal tubular cells, HK-2, the effects of sodium selenite (Na2SeO3) and to evaluate the expression of SEPP1 as a marker of injury. Materials and Methods: HK-2 cells were pre-incubated with 100 nM Na2SeO3 for 24 h, and then, treated for 24 h with CoCl2 (500 µM), a chemical hypoxia inducer. The results were derived from an ROS assay, MTT, and Western blot analysis. Results: The pre-treatment determined an increase in cells' viability and a reduction in reactive oxygen species (ROS), as shown by MTT and the ROS assay. Moreover, by Western blot an increase in SEPP1 expression was observed after hypoxic injury as after adding sodium selenite. Conclusions: Our preliminary results shed light on the possible role of selenium supplementation as a means to prevent oxidative damage and to increase SEPP1 after acute kidney injury. In our in vitro model, SEPP1 emerges as a promising biomarker of kidney injury, although further studies in vivo are necessary to validate our findings.

Nano-Selenium inhibited antibiotic resistance genes and virulence factors by suppressing bacterial selenocompound metabolism and chemotaxis pathways in animal manure.

Numerous antibiotic resistance genes (ARGs) and virulence factors (VFs) found in animal manure pose significant risks to human health. However, the effects of graphene sodium selenite (GSSe), a novel chemical nano-Selenium, and biological nano-Selenium (BNSSe), a new bioaugmentation nano-Se, on bacterial Se metabolism, chemotaxis, ARGs, and VFs in animal manure remain unknown. In this study, we investigated the effects of GSSe and BNSSe on ARGs and VFs expression in broiler manure using high-throughput sequencing. Results showed that BNSSe reduced Se pressure during anaerobic fermentation by inhibiting bacterial selenocompound metabolism pathways, thereby lowering manure Selenium pollution. Additionally, the expression levels of ARGs and VFs were lower in the BNSSe group compared to the Sodium Selenite and GSSe groups, as BNSSe inhibited bacterial chemotaxis pathways. Co-occurrence network analysis identified ARGs and VFs within the following phyla Bacteroidetes (genera Butyricimonas, Odoribacter, Paraprevotella, and Rikenella), Firmicutes (genera Lactobacillus, Candidatus_Borkfalkia, Merdimonas, Oscillibacter, Intestinimonas, and Megamonas), and Proteobacteria (genera Desulfovibrio). The expression and abundance of ARGs and VFs genes were found to be associated with ARGs-VFs coexistence. Moreover, BNSSe disruption of bacterial selenocompound metabolism and chemotaxis pathways resulted in less frequent transfer of ARGs and VFs. These findings indicate that BNSSe can reduce ARGs and VFs expression in animal manure by suppressing bacterial selenocompound metabolism and chemotaxis pathways.

Humic acid chelated selenium is suitable for wheat biofortification.

BACKGROUND: Selenium rich bread is a good carrier of selenium, but the inorganic selenium used in the actual production process is toxic. It is necessary to develop a new green bread production technology. The extraction and utilization of humic acid chelated selenium from selenium-rich soil is beneficial for reducing resource waste and pollution without destroying the soil ecosystem in selenium-deficient areas. Sodium selenite and nanoselenium were selected as controls because they are commonly used as selenium agronomic enhancers in production. RESULTS: Humic acid chelated selenium can be absorbed and accumulated by wheat leaves, and humic acid chelated selenium had no significant effect on wheat yield, which was also shown in the treatments with nanoselenium and sodium selenite. Excessive accumulation of selenium in wheat grains can lead to a deterioration of processing quality. Among them, the use of excessive nanoselenium at the filling stage inhibited the accumulation of wheat grain protein, whereas humic acid chelated selenium is beneficial to grain protein accumulation and has the least negative effect on the processing quality. The accumulation of excessive selenium in wheat seeds had a negative effect on seed germination and growth; specifically, the seed vigor of wheat treated with humic acid chelated selenium was higher than that of untreated wheat. CONCLUSION: Humic acid chelated selenium is particularly suitable for the whole process of Se-enriched bread wheat production. The seed vigour of wheat treated with humic acid chelated selenium, which supplied a moderate amount of selenium, was higher than that of untreated wheat. Conversely, the accumulation of excessive selenium in wheat seeds reduced germination and seedling growth. © 2023 Society of Chemical Industry.

Selenium toxicity and bioaccumulation in selenium-enriched fly (Chrysomya megacephala) maggots.

Selenium (Se) is an essential trace element for human health, and as a potential animal feed, the Chrysomya megacephala (Fabricius) fly is rich in protein and fat. By using different concentrations of sodium selenite (0, 30, 50, 70 mg kg-1), the possibility of biological Se enrichment in C. megacephala (Fabricius) maggots (CMMs) was investigated. The accumulation, Se speciation, enzymatic activity, and concentrations of copper (Cu), zinc (Zn), chromium (Cr), and cadmium (Cd) in the maggots were also determined. Transcriptomics was also used to investigate the mechanism of the Se response to CMM genes. The results showed that the CMMs had a survival rate of > 80% at Se exposure concentrations ranging from 0 to 100 mg kg-1. The optimal concentration of sodium selenite for CMM growth was 50 mg kg-1, and the weight, protein content, and total Se accumulation of the larvae (10.8 g, 53.5%, and 72.6 ± 3.36 mg kg-1 (DW), respectively) were considerably higher than the control and other exposure doses (p < 0.05). In addition, Se improved the ability of maggots to absorb Cu and Zn, decreased malondialdehyde (MDA) and lipid peroxidation, but improved the antioxidant activities of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPX). Furthermore, Se negatively affected the absorption of Cd and Cr. According to the transcriptomic findings, Se supplementation can boost protein synthesis and control both antioxidant and non-antioxidant enzyme activity in CMMs. Therefore, our findings showed that Se-enriched CMMs may counteract the toxicity of Cd and Cr, and Se is an effective supplement for improving the consumption safety of cultured animals fed containing CMMs.

Sodium Selenite Modulates IDO1/Kynurenine, TLR4, NF-κB and Bcl2/Bax Pathway and Mitigates Acetic Acid-Induced Colitis in Rat.

BACKGROUND/AIMS: Colitis is a main presentation of inflammatory bowel disease (IBD) and yet, has no definitive cure. Currently, corticosteroids, anti-tumor necrosis factor (anti-TNF) agents and 5-aminosalicylic acid derivatives are prescribed for management of colitis. Except their failure rate, they are not always tolerated because of their severe adverse effects. Additive formulas with fewer adverse effects may improve the treatment of colitis. METHODS: In this study, colitis was induced with intra-rectal injection of three concentrations of acetic acid (4, 6 and 8 v/v). Each group received sodium selenite (0.5 mg/kg) or saline, gavaged on days 0 and 1 for treatment. Two days after induction of colitis, rats were sacrificed and the end part of their colons were resected for macroscopic and microscopic evaluation and molecular measurement. RESULTS: Sodium selenite improved macroscopic and microscopic view of the colon, decreased cryptitis, crypt abscess and inflammatory cells infiltration and partly maintained mucosal structure. Sodium selenite markedly reduced tissue levels of malondialdehyde (MDA), TNF-α and interferon γ (INF-γ) and decreased myeloperoxidase (MPO) activity. Treatment with sodium selenite also significantly downregulated IL17, IL22, indoleamine 2,3-dioxygenase (IDO1), and kynurenine levels. Western blotting revealed that sodium selenite prevented apoptosis by increasing bcl2/Bax ratio. Furthermore, our findings showed that sodium selenite significantly downregulated the upstream inflammatory molecules such as nuclear factor kappa B (NF-κB) and toll-like receptor 4 (TLR4) in colitis. CONCLUSION: These findings show that sodium selenite alleviates inflammatory response and oxidative stress and protects against colitis.

Sodium selenite inhibits proliferation and metastasis through ROS-mediated NF-κB signaling in renal cell carcinoma.

BACKGROUND: Sodium selenite (SSE) has been reported to exert anti-tumor effects in several cancer cells. However, the underlying mechanisms in renal cancer are yet to be elucidated. The effects of SSE on the proliferation, metastasis, and apoptosis of renal cancer cells, as well as its mechanism, were investigated in this study. METHODS: ACHN and 786-O renal cancer cells were treated with different concentrations of SSE, MTT, and colony formation assays were used to detect the proliferation ability of cells. The migration of cells was detected using scratch-wound-healing and transwell-migration assays. The effect of SSE on apoptosis was assessed by AnnexinV-FITC/PI double staining. Besides, Western blotting was employed to detect the protein-expression level and elucidate the underlying pathways. We also made subcutaneous xenografts in athymic mice to verify the effect of SSE on tumor growth in vivo. RESULTS: Our results demonstrated that treatment with SSE resulted in significant inhibition of cell proliferation and migration. Flow cytometry and Western blot confirmed that SSE induced apoptosis via the endogenous apoptotic pathway. We also confirmed that SSE treatment causes an increase in intracellular reactive oxygen species (ROS) levels, resulting in the inhibition of nuclear transcription factor-κB (NF-κB) signaling. Modulation of the ROS level by the chemical inhibitor N-acetyl-cysteine reversed the effect of SSE on cells. Similarly, subcutaneous xenografts in athymic mice models showed that SSE inhibits tumor growth in vivo. CONCLUSION: These results indicate that SSE inhibits proliferation and migration and induces apoptosis via ROS mediated inhibition of NF-κB signaling in renal cancer cells.

Antagonistic activity of selenium-enriched Bifidobacterium breve against Clostridioides difficile.

Probiotics have the potential to be used in the prevention of Clostridioides difficile infection (CDI). In this study, selenium (Se)-enriched Bifidobacterium breve YH68-Se was obtained under optimal culture conditions with single-factor and response surface optimization. The overall environmental resistance of YH68-Se was superior to that of the parental strain YH68, mainly reflected in the substantial improvement of antioxidant activity and gastrointestinal tolerance. YH68-Se dramatically inhibited C. difficile growth, spore, biofilm, toxin production, and virulence gene expression, rapidly disrupted C. difficile cell membrane permeability and integrity, and altered the membrane proton motive force (PMF), induced a large outflow of intracellular substances and eventually caused bacterial death. The main factor inducing this process originated from the lactic acid (LD) in YH68-Se. In addition, the LD production of YH68 increased with increasing selenite concentration and was accompanied by enhanced activities of thioredoxin reductase (TrxR), glutathione peroxidase (GSH-Px), and increased concentration of autoinducer-2 (AI-2), which may be the crucial factors contributing to the outstanding probiotic properties of YH68-Se and their potent antagonism of C. difficile. KEY POINTS: • Compared with the parental strain B. breve YH68, the environmental resistance of YH68-Se was improved. • YH68-Se was able to produce more lactic acid, which suppressed the important physiological activities of C. difficile and rapidly disrupted their cell membrane structures. • Sodium selenite in the suitable concentration range gradually increases the yield of lactic acid and phenylacetic acid, increased the concentration of autoinducer-2, and enhanced the activities of antioxidant enzymes TrxR and GSH-Px in YH68.

Comparative efficacy of bio-selenium nanoparticles and sodium selenite on morpho-physiochemical attributes under normal and salt stress conditions, besides selenium detoxification pathways in Brassica napus L.

Selenium nanoparticles (SeNPs) have attracted considerable attention globally due to their significant potential for alleviating abiotic stresses in plants. Accordingly, further research has been conducted to develop nanoparticles using chemical ways. However, our knowledge about the potential benefit or phytotoxicity of bioSeNPs in rapeseed is still unclear. Herein, we investigated the effect of bioSeNPs on growth and physiochemical attributes, and selenium detoxification pathways compared to sodium selenite (Se (IV)) during the early seedling stage under normal and salt stress conditions. Our findings showed that the range between optimal and toxic levels of bioSeNPs was wider than Se (IV), which increased the plant's ability to reduce salinity-induced oxidative stress. BioSeNPs improved the phenotypic characteristics of rapeseed seedlings without the sign of toxicity, markedly elevated germination, growth, photosynthetic efficiency and osmolyte accumulation versus Se (IV) under normal and salt stress conditions. In addition to modulation of Na+ and K+ uptake, bioSeNPs minimized the ROS level and MDA content by activating the antioxidant enzymes engaged in ROS detoxification by regulating these enzyme-related genes expression patterns. Importantly, the main effect of bioSeNPs and Se (IV) on plant growth appeared to be correlated with the change in the expression levels of Se-related genes. Our qRT-PCR results revealed that the genes involved in Se detoxification in root tissue were upregulated upon Se (IV) treated seedlings compared to NPs, indicating that bioSeNPs have a slightly toxic effect under higher concentrations. Furthermore, bioSeNPs might improve lateral root production by increasing the expression level of LBD16. Taken together, transamination and selenation were more functional methods of Se detoxification and proposed different degradation pathways that synthesized malformed or deformed selenoproteins, which provided essential mechanisms to increase Se tolerance at higher concentrations in rapeseed seedlings. Current findings could add more knowledge regarding the mechanisms underlying bioSeNPs induced plant growth.

Alleviating effects of selenium on fluoride-induced testosterone synthesis disorder and reproduction toxicity in rats.

Fluoride (F) exists widely in food, water and other natural resources, and can cause damage to the reproductive system of human and animals. Studies have shown that selenium (Se) is a necessary trace element to maintain the normal male reproductive system. However, it is not clear whether it can alleviate the damage of reproductive system induced by F. Hence, sodium fluoride (NaF) was administered singly in drinking water at 100 mg L-1 alone and co-administered by drinking with sodium selenite (Na2SeO3) at 0.5, 1.0, 2.0 mg L-1 for 10 consecutive weeks. The results demonstrated that the sperm deformity rate were increased significantly by F, however, it was improved significantly after the addition of 2.0 mg L-1 Na2SeO3. The contents of glutathione peroxidase 4 (GPX-4), selenoprotein P (SePP), pregnenolone (PREG), androstenedione (ASD), and testosterone (T) were reduced obviously in the F group, however, it was increased significantly after adding 0.5, 1.0 and 2.0 mg L-1 Na2SeO3. F decreased noticeably the mRNA and protein expression levels of steroidogenic acute regulatory protein (StAR), cytochrome P450 cholesterol side chain lyase (P450scc), 3ß-hydroxysteroid dehydrogenase (3ß-HSD), cytochrome P450 17α-hydroxylase (P450c17) and 17ß-hydroxysteroid dehydrogenase (17ß-HSD), which was increased obviously after the addition of 1.0 and 2.0 mg L-1 Na2SeO3. In summary, 2.0 mg L-1 Na2SeO3 can alleviate testosterone synthesis disorder induced by F via reducing oxidative stress, increasing the level of selenoprotein in testis and regulating the content of related hormones and enzyme activity during testosterone synthesis pathway.

Immunomodulatory and Anti-Inflammatory Properties of Selenium-Containing Agents: Their Role in the Regulation of Defense Mechanisms against COVID-19.

The review presents the latest data on the role of selenium-containing agents in the regulation of diseases of the immune system. We mainly considered the contributions of selenium-containing compounds such as sodium selenite, methylseleninic acid, selenomethionine, and methylselenocysteine, as well as selenoproteins and selenium nanoparticles in the regulation of defense mechanisms against various viral infections, including coronavirus infection (COVID-19). A complete description of the available data for each of the above selenium compounds and the mechanisms underlying the regulation of immune processes with the active participation of these selenium agents, as well as their therapeutic and pharmacological potential, is presented. The main purpose of this review is to systematize the available information, supplemented by data obtained in our laboratory, on the important role of selenium compounds in all of these processes. In addition, the presented information makes it possible to understand the key differences in the mechanisms of action of these compounds, depending on their chemical and physical properties, which is important for obtaining a holistic picture and prospects for creating drugs based on them.

Treatment of Ginkgo biloba with Exogenous Sodium Selenite Affects Its Physiological Growth, Changes Its Phytohormones, and Synthesizes Its Terpene Lactones.

Ginkgolide is a unique terpenoid natural compound in Ginkgo biloba, and it has an important medicinal value. Proper selenium has been reported to promote plant growth and development, and improve plant quality, stress resistance, and disease resistance. In order to study the effects of exogenous selenium (Se) on the physiological growth and the content of terpene triolactones (TTLs) in G. biloba seedlings, the seedlings in this work were treated with Na2SeO3. Then, the physiological indexes, the content of the TTLs, and the expression of the related genes were determined. The results showed that a low dose of Na2SeO3 was beneficial to plant photosynthesis as it promoted the growth of ginkgo seedlings and increased the root to shoot ratio. Foliar Se application significantly increased the content of soluble sugar and protein and promoted the content of TTLs in ginkgo leaves; indeed, it reached the maximum value of 7.95 mg/g in the ninth week, whereas the application of Se to the roots inhibited the synthesis of TTLs. Transcriptome analysis showed that foliar Se application promoted the expression levels of GbMECPs, GbMECT, GbHMGR, and GbMVD genes, whereas its application to the roots promoted the expression of GbDXS and GbDXR genes. The combined analysis results of metabolome and transcriptome showed that genes such as GbDXS, GbDXR, GbHMGR, GbMECPs, and GbCYP450 were significantly positively correlated with transcription factors (TFs) GbWRKY and GbAP2/ERF, and they were also positively correlated with the contents of terpene lactones (ginkgolide A, ginkgolide B, ginkgolide M, and bilobalide). Endogenous hormones (MeJA-ILE, ETH, and GA7) were also involved in this process. The results suggested that Na2SeO3 treatment affected the transcription factors related to the regulation of endogenous hormones in G. biloba, and further regulated the expression of genes related to the terpene synthesis structure, thus promoting the synthesis of ginkgo TTLs.

Effects of selenium application concentration, period and method on the selenium content and grain yield of Tartary buckwheat of different varieties.

BACKGROUND: As a potential selenium-enriched crop, it is of great significance to study the selenium application of Tartary buckwheat. Therefore, to study the effects of selenium application concentration, variety, selenium application period and method on the grain selenium content and yield of Tartary buckwheat, an orthogonal experimental design was used to carry out field experiments in the Jinzhong and Northwest Shanxi ecological regions at the same time. Heifeng 1 and Jinqiao 2 were applied at the branching stage and flowering stage in the Jinzhong, and Heifeng 1 and Jinqiao 6 were applied at the early flowering stage and peak flowering stage in the Northwest Shanxi with different concentrations of sodium selenite (0, 1.37, 2.74, 5.48, 8.22, 12.33, 18.495, 27.7425 g hm-2 ) by foliar spraying and soil application. RESULTS: The results showed that the selenium content in Tartary buckwheat grains was positively correlated with the selenium application concentration and increased with increasing selenium application concentration, while the yield of Tartary buckwheat first increased and then decreased with the selenium application concentration. The grain selenium content and yield of Tartary buckwheat were affected by the selenium application concentration, variety and application method. CONCLUSION: The most effective selenium biofortification program was spraying 2.32 g hm-2 sodium selenite on the leaves of Heifeng 1 at the early flowering stage in the Jinzhong. In the Northwest Shanxi, spraying 11.01 g hm-2 sodium selenite on the leaves of Jinqiao 6 at the flowering stage was the most effective selenium biofortification program. © 2022 Society of Chemical Industry.