Different Concentrations Of Se Research Articles

Efeito protetor da suplementação de hidróxi-selenometionina na dieta de tambaqui (Colossoma macropomum) submetidos ao estresse pelo transporte

ABSTRACT Selenium (Se) is an antioxidant mineral and has been included in fish feed formulations in the organic form of hydroxy-selenomethionine (OH-SeMet). This study evaluated how different concentrations of this substance, supplemented in the diet, act on tambaqui (Colossoma macropomum) muscle before and after a stressor (transportation). Juvenile fishes were divided into five treatments receiving 0.0; 0.3; 0.6; 0.9; 1.2 mg kg-1 Se supplementation for 75 days. After that period, the fish were exposed to transportation for four hours. Sampling of muscle tissue for the measurement of biochemical parameters occurred on day 75, prior to transportation, and one week after transportation (day 83). The activity of enzymes superoxide dismutase and glutathione-S-transferase did not change. Supplementation with 1.2 mg kg-1 Se increased the level of reduced glutathione before transportation, and 0.9 and 1.2 mg kg-1 Se reduced the level of thiobarbituric acid reactive substances levels before and after transportation. After transportation, we observed reduced glutathione levels in fish treated with 0.3, 0.6 and 1.2 mg kg-1, reduced ascorbic acid level in fish fed 0.6 mg kg-1 Se, and reduced total protein concentration in fish fed 0.3 mg kg-1 Se, as compared to the levels before transportation. In conclusion, the presence of different concentrations of Se in the fish diet promoted different patterns of response to redox status, minimizing oxidative damage generated by the stressor event.

Interconnections of primary and secondary metabolites of Astragalus verus cells under selenium treatment

Selenium (Se) is a beneficial microelement with dose dependent effects on plants. At low concentrations, it stimulates antioxidant system but at high doses cause cell death. In the present study, the effects of different concentrations of Se (0, 0.5, 2.5, 12.5, and 62.5 μM) on metabolome of a cell line of Astragalus verus was evaluated. Seven-old days cells were treated with Se in the middle of their logarithmic growth phase for one week. Along with the increasing concentrations of Se, growth and total contents of soluble sugars and proteins, auxin and brassinosteroid decreased. However, the contents of ascorbate, glutathione, certain phenolics, free amino acids, and the activity of antioxidant enzymes increased. The results indicated the signaling role of monosaccharides and their synergistic behavior with auxin and brassinosteroid and critical functions of ascorbate and glutathione in response of A. verus to Se.

Impact of foliar spray with Se, nano-Se and sodium sulfate on growth, yield and metabolic activities of red kidney bean

Sulfur (S) is an essential microelement for plants. Based on the chemical similarity between Se and S, selenium may affects sulphur uptake by plants. This work aimed at investigating the effect of foliar spray with sodium selenate, gum arabic coated selenium nanoparticles (GA-SeNPs ≈ 48.22 nm) and sodium sulfate on red kidney bean (Phaseolus vulgaris L.) plants. Each treatment was used at 0.0, 1, 5, 10 and 50 µM, alone or combination of sodium sulfate with either Se or nano-Se, each at 0.5, 2.5 and 5 µM concentrations. The effect of foliar spray on vegetative growth, seed quality, and some metabolic constituents of red kidney bean (Phaseolus vulgaris L.) plants were investigated. Selenium nanoparticles have been synthesized through the green route using gum arabic (as a stabilizing and coating agent. Foliar application of different concentrations of Se, nano-Se, Na2SO4 up to 10 μM and their interaction were effective in increasing the growth criteria (i.e. shoot and root lengths, plant fresh and dry weights, number of leaves and photosynthetic area (cm2 plant−1).There was also a significant increase in photosynthetic pigment contents, yield (i.e., 100-seed weight), total carbohydrate, crude proteins and mineral contents in both leaf as compared to their untreated control plants. Furthermore, interaction between sodium sulfate with nano-Se or Se, each at 5 µM significantly increased the vegetative growth, 100-seed weight, and pigment contents in leaves and improved the nutritional value and quality of red kidney bean seeds.

Transfer of Se from sediments to the western mosquitofish Gambusia affinis: Tissue distribution, accumulation, and effects on the antioxidant physiology

Selenium (Se) has been shown to cause various toxicities in predatory species (i.e., fish and birds) in Se-contaminated aquatic environments. However, trophic transfer of Se from abiotic environments to freshwater fish has been relatively less addressed. In this study, 2-month-old mosquitofish (Gambusia affinis) were fed Se-enriched oligochaete (Lumbriculus variegatus, exposed to different concentrations of Se(IV) at 0.0, 3.0, 10.0, and 30.0 µg/g dry weight for 7 days) for 45 days. Tissue distribution, Se speciation, and effects on the antioxidant physiology in G. affinis were assessed. The results showed Se was rapidly accumulated in the oligochaete, with 6.30 ± 1.20, 16.20 ± 2.10, and 34.50 ± 2.40 µg/g dw of total Se levels in the worms exposed to 3.0, 10.0, and 30.0 µg/g of Se(IV), respectively. Total Se levels were increased in a dose-dependent manner in fish tissues and Se(IV) from sediments was maternally transferred to the fish embryos. Se-Met-and Se-Cys-were the predominant Se species in the worm and fish tissues, accounting for a minimum of 91.01% of the total Se. Furthermore, increased lipid peroxidation and altered the activities of antioxidant enzymes and levels of GSH were noticed in G. affinis fed the Se-enriched L. variegatus. This study has demonstrated that Se(IV) is transferred from an abiotic vector to freshwater organisms, disturbing the antioxidant physiology in G. affinis and potentially their offspring. This study highlights the importance of dietary exposure on the accumulation and toxicity of Se in aquatic organisms.

Effects of Selenium on Growth and Biochemical Characters of Tissue Culture Seedlings of Sophora tonkinensis

Background Selenium (Se) plays a key role in controlling several processes in plant development, such as root growth and regulation of enzyme activity. However, research on the effects of Se in Sophora tonkinensis, a medicinal plant, has not been reported. To elucidate the effect of Se on the accumulation of secondary metabolites in tissue-cultured seedlings of S. tonkinensis. Materials and Methods Tissue culture seedlings of S. tonkinensis was treated with different concentrations of Se in the rooting medium. Agronomic traits of roots and concentrations of hormones and some secondary metabolites were measured from seedlings. Results The results show that (1) root growth of tissue culture seedlings were stimulated by Se; (2) a specific amount of Se enhanced the activities of peroxidase (POD) and superoxide dismutase (SOD), as well as the production and storage of soluble proteins and chlorophyll; and (3) Se treatment lowered brassinolide (BR) content, and 15 mg/L Se minimized abscisic acid (ABA) content, while 60 mg/L Se enhanced ABA content. The gibberellin (GA3) content in seedlings increased significantly compared with the control under the treatment of 60 mg/L Se. Conclusion Se concentration of 30 mg/L facilitated matrine and oxymatrine production and accumulation in stem/leaf tissues.

Ameliorative effects of different doses of selenium against fluoride-triggered apoptosis and oxidative stress-mediated renal injury in rats through the activation of Nrf2/HO-1/NQO1 signaling pathway.

Excess fluoride (F) exposure can cause oxidative stress in the kidney. As an antioxidant, selenium (Se) can potentially protect the kidney from F-induced injury in rats. Hence, the histopathological, renal biochemical, oxidative stress, and apoptotic-related indices upon exposure to 100mg/L sodium fluoride (NaF) and various doses of sodium selenite (Na2SeO3; 0.5, 1, and 2mg/L) were assessed. Our results demonstrated that F-mediated renal structural damage and apoptosis elevated the content of serum creatinine (SCr), inhibited the activity of catalase (CAT) in serum, and increased the production of reactive oxygen species (ROS) in kidney and malondialdehyde (MDA) in serum. Interestingly, 1mg/L dietary supplementation of Se tangibly mitigated these injuries. Furthermore, F could also change the gene and protein expression of the nuclear factor erythroid 2-related factor 2 (Nrf2), heme oxygenase-1 (HO-1), and NAD(P)H quinone oxidoreductase1 (NQO1). Concomitantly, the different concentrations of Se notably alleviated their expression. Taken together, 1-2mg/L Se ameliorated F-induced renal injury through oxidative stress and apoptosis-related routes. The recorded ameliorative effects might be related to the activation of the Nrf2/HO-1/NQO1 signaling pathway.

Selenium conditioning decreases antioxidant enzyme activity and delays germination potency of Macrotyloma uniflorum and Vigna radiate

ObjectiveThis study focuses on the effect of Selenium (Se) on the germination of Macrotyloma uniflorum and Vigna radiate seeds. MethodsBoth the seeds were soaked in solutions containing different concentrations of Se (0 mg/L, 0.5 mg/L, 2.5 mg/L and 5.0 mg/L), for different time intervals (3 h, 6 h, 9 h and 12 h). After soaking, germination efficacy of the seeds was assayed. Total carbohydrate and starch content of the seeds were monitored along with α-amylase activity. The antioxidant activity was also estimated through measuring Catalase, Superoxide dismutase activity and amount of reduced Glutathione as well. ResultsThe result unveiled that at 0.5 mg/L of Se did not affect the germination at 3 h of soaking, however upon increasing the duration of soaking the germination efficacy is statistically decreased. 3 h soaking of seeds with 2.5 mg/L and 5.0 mg/L of Se reduced the germination efficacy of both the seeds. Further it was observed that increasing the duration of soaking from 3 h to 6hrs, 9 h and 12 h, inhibited the germination potency (P < 0.05). Total carbohydrate and starch content were increased (P < 0.05) in both the seeds soaked in 0.5 mg/L of Se for 3 h, on the other hand there is no statistical difference at 2.5 mg/L and 5.0 mg/L of Se. The α-amylase activities in different experimental samples are in line with carbohydrate and starch levels. Furthermore, it was observed that reduced glutathione and antioxidant enzyme activities were increased (P < 0.05) in both the seeds soaked in 0.5 mg/L of Se for 3 h, however these alterations were statistically reduced (P < 0.05) at 2.5 mg/L and 5.0 mg/L of Se. ConclusionThe present study documents higher concentration of Se could decrease the germination efficacy of M. uniflorum and V. radiate seeds through oxidative stress mediated pathway. On the other hand, lower concentration delays germination. Soaking of M. uniflorum and V. radiate seeds in less concentrated Se solution increases the carbohydrate and starch content compromising germination efficacy.

Metabonomic analysis of the haemolymph reveals the dual effects of dietary selenium supplementations on growth of silkworm Bombyx mori

Selenium (Se) is a vital micronutrient for the growth and development of organisms; however, its deficiency and toxicity pose worldwide challenges. Herein, we investigated the absorption, accumulation effect, and distribution of Se in silkworms, and tested the effect of Se feeding on the antioxidant indexes of silkworm haemolymph. Results showed that low concentrations of Se (50 μM and 100 μM) significantly increased the enzyme activities of catalase, glutathione peroxidase, glutathione S-transferase and superoxide dismutase in the silkworm haemolymph compared to control and 200 μM group. In addition, metabonomic analysis could reveal the metabolic changes in silkworm haemolymph after treatment with different concentrations (50 μM, and 200 μM) of Se. Compared to un-treatment group, the amount of 90 metabolites in both of 50 μM and the 200 μM Se-treated groups displayed significant differences, with 50 up-regulated and 40 down-regulated in 50 μM group, 36 up-regulated and 54 down-regulated in 200 μM group, respectively. The main different metabolites were amino acids, carbohydrates, lipids, nucleotide metabolites and their derivatives. These results suggest that Se could affect the carbohydrate metabolism in silkworms. The difference in metabolites was subject to different changes under different concentrations of Se and consequently altered their metabolic functions to meet the required energy demands under the Se toxic stress conditions.

Ability of the Saccharomyces cerevisiae Y904 to tolerate and adapt to high concentrations of selenium

The alcoholic fermentation industry generates a large surplus of yeasts, which, in turn, have the ability to bioaccumulate minerals and enable their bioavailability after cell autolysis. Among these minerals, selenium (Se) stands out, which participates in the formation of antioxidant enzymes. The objectives of the work were to define the minimum and maximum concentration of Se that yeasts (Saccharomyces cerevisiae – Y904) support and the concentrations that they tolerate once adapted. To this end, a test of tolerance to Se was carried out, using treatments with different concentrations of Se. The adaptive process started at the maximum concentration obtained in the tolerance test of 60 mg mL-1, with increasing addition of 6 mg mL-1, reaching up to 246 mg mL-1 of Se. The macromorphological characteristics and number of colony forming units (CFU) were evaluated. It was identified that yeasts without adaptation grew on substrate containing up to 60 mg mL-1 of Se and those adapted, up to 246 mg mL-1 of Se. In addition to the reduction in yeast growth speed, from the concentration of 84 mg mL-1 of Se in the medium, morphological changes in colony color were observed. It is concluded that non-adapted yeasts support up to 60 mg mL-1 of Se and, after the adaptive process, they support 246 mg mL-1 of Se in the medium after the adaptive process, which adds value to the final product, and makes yeasts suitable for human nutrition as a supplement or even in the formulation of probiotics.

Selenium Deficiency Caused Fibrosis as an Oxidative Stress-induced Inflammatory Injury in the Lungs of Mice.

Selenium (Se) is a vital trace element in the regulation of inflammation and antioxidant reactions in both animals and humans. Se deficiency is rapidly affecting lung function. The present study investigated the molecular mechanism of Se deficiency aggravates reactive oxygen species (ROS)-induced inflammation, leading to fibrosis in lung. Mice fed with different concentrations of Se to establish the model. In the Se-deficient group, the ROS and malondialdehyde (MDA) was increased, and the activities of glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), total antioxidant capacity (T-AOC), and catalase (CAT) reduced. The histopathological observation showed that Se deficiency lead to lung texture damage with varying degrees of degeneration, necrosis, shedding of some alveolar epithelial cells, and inflammatory cell infiltration. Immunohistochemistry showed that the expression of α-smooth muscle actin (α-SMA) increased. The fibrosis index was verified with Sirius red staining. The ELISA and qPCR results showed that the inflammatory cytokines (TNF-α and IL-1β) and ECM (collagen I, collagen IV, fibronectin, and laminin) were increased with ROS increasing, which was induced by Se deficiency. The results displayed that oxidative stress with Se deficiency led to an increase in tissue inhibitors of metalloproteinase (TIMPs), but a decrease in matrix metalloproteinases (MMPs). All the results indicated that Se deficiency induced excessive ROS accumulation to generate inflammation, which disrupted ECM homeostasis and aggravated fibrosis in the lung.

Novel mechanistic insights of selenium induced microscopic, histochemical and physio-biochemical changes in tomato (Solanum lycopersicum L.) plant. An account of beneficiality or toxicity

Selenium (Se) is a well-known beneficial element in plants. The window of Se between toxic and optimal concentration is narrow and uneven which fluctuates with plants species. This experiment was aimed to investigate the morpho-physiological, microscopic and histochemical responses of two different varieties of tomato (S-22 and PKM-1), exposed to different concentrations of Se (0, 10, 40 or 80 µM), applied to soil at 30 days after transplantation (DAT). At 40 DAT, it was observed that high concentrations (40 or 80 µM) of Se radically increased oxidative stress examined by elevated reactive oxygen species (ROS), malondialdehyde (MDA) content, cell death, electrolyte leakage and decreased chlorophyll content leading phenotypic symptoms of Se-induced toxicity like stunted growth and chlorosis. Furthermore, high doses of Se altered the chloroplast and stomatal organisation, and adversely affected the photosynthetic performance of plants. But low concentration of Se improved the plant dry mass, photosynthesis, Rubisco activity, protein content and maintained the steady-state equilibrium among ROS generation and antioxidant enzymes like catalase, peroxidase and superoxide dismutase. Our outcomes proposed that high concentration of Se generated toxicity (phyto-selenosis), whereas lower concentration of Se-triggered positive impact by improving growth, photosynthetic traits and maintaining steady-state equilibrium between scavenging-system and ROS generation.

Effects triggered by foliar selenium application on growth, enzyme activities, mineral nutrients and carbohydrates in lettuce under an aquaculture system

Se has beneficial effects on plants, through the stimulation of plant productivity, the reduction of abiotic stresses, and the improvement in N metabolism. Therefore, we investigated the effect of the foliar application of different concentrations of Se (0, 4, 8 and 16 μmol L−1) on lettuce plants grown in an aquaponics system (fish water) compared with a control (conventional soilless fertigation). The NO3- concentration supplied by the fish water was 47% of the control solution. The results showed a reduction in the fresh weight of lettuce plants irrigated with the fish water mixture treatment, along with an increase in sugar concentration. However, the application of Se at 4 and 16 μmol L−1, prompted a relief of this stress, reducing both lipid peroxidation and the sugar content, and increasing the nitrate concentration. In addition, in the case of the highest concentration of Se (16 μmol L−1), the values of nitrate were comparable those control plants. We show the importance of sprayed Se in increasing the efficiency of N utilization, in addition to lessening environmental issues for aquaponics culture.

Electronic, optical and transport properties of perovskite BaZrS3 compound doped with Se for photovoltaic applications

The chalcogenide perovskite BaZrS3 compound has a huge scientist interest recently due to their properties, and it is known as a new generation of photovoltaic semiconductor, with a specific gap value which is a major element who influences on the efficiency of panels. In this work, the electronic, optical and transport properties of perovskite BaZrS3-xSex compound doped with different concentrations of Se (x = 0%, 10%, 15% and 20%) are investigated using the density functional theory (DFT). It is found that the band gap values decreases by increasing the doping concentrations from 1.59 eV (for 0% of Se) to 1.35 eV (for 20% of Se). In addition, the optical properties indicate that the perovskite BaZrS3 is a good absorber. Also, from the transport proprieties we observed that the BaZrS3-xSex compound is a p-type material. These results show that the BaZrS3 compound doped with Se is a good candidate for photovoltaics applications.

Se Deficiency Induced Inflammation Resulting to a Diminished Contraction of the Small Intestinal Smooth Muscle in Mice.

Selenium (Se) is an essential trace element for both humans and animals. Se deficiency leads to myocardial injury, reproductive disorder, increased exudation, inflammatory injury, and other diseases. The present study analyzed the relationships of Se deficiency, inflammation, and smooth muscle contraction in the small intestine, which is the main tissue that digests and absorbs Se. The model was established by feeding the animals diets with different concentrations of Se. The results showed that the dietary Se content was positively correlated with the blood Se concentration and the intestinal Se concentration. ROS and MPO activity increased with the lack of Se. TNF-α, IL-1β, and IL-6 expression was increased at both the mRNA and protein levels with Se deficiency. The pathways tested showed that the IκBα, NF-κB p65, p38, ERK, and JNK phosphorylation levels were significantly increased with the lack of Se. Moreover, the contractility analysis confirmed that contraction of the intestinal smooth muscle was attenuated by Se deficiency, as shown by the MedLab data acquisition system. These results further illuminated the relationship between inflammation and inhibition of smooth muscle contraction under Se deficiency in the small intestine. The Ca2+ concentration was decreased, and RhoA phosphorylation and ROCK expression were also inhibited by Se deficiency. The results also showed that MLC protein phosphorylation decreased with Se deficiency. In conclusion, the present study indicated that inflammation under Se deficiency leads to the inhibition of smooth muscle contraction in the small intestine.

Influence of selenium biofortification on the bioactive compounds and antioxidant activity of wheat microgreen extract

The study was conducted to confirm the effects of selenium biofortification on the bioactive compounds and antioxidant activity of wheat microgreen extract. The microgreens were cultivated in the DFT hydroponic system with different concentrations of Se (0 [control], 0.125, 0.25, 0.50, and 1.00 mg/L from sodium selenite) in a growth chamber by controlling temperature (25/20 °C, day/night), light (12 h light/dark; intensity 150 µmol‧m−2‧s−1 with white fluorescence lamp), and humidity (60%) for 10 days. Se biofortification increased the germination rate and decreased microgreen length and yield. Chlorophyll and carotenoid levels increased in the Se-biofortified microgreen extract. Bioactive compounds such as phenolics, flavonoids, vitamin C, and anthocyanin significantly increased in 0.25–0.50 mg/L of Se-biofortified microgreen extracts. Antioxidant (ABTS, DPPH, NSA and SOD-like) activity also increased at moderate levels (0.25–0.50 mg/L) of Se biofortification. Therefore, Se biofortification may be useful for the industrial manufacture of new products from wheat microgreen extract.

Impact of Selenium and Copper Nanoparticles on Yield, Antioxidant System, and Fruit Quality of Tomato Plants.

The effects of nanoparticles (NPs) on plants are contrasting; these depend on the model plant, the synthesis of the nanoparticles (concentration, size, shape), and the forms of application (foliar, substrate, seeds). For this reason, the objective of this study was to report the impact of different concentrations of selenium (Se) and copper (Cu) NPs on yield, antioxidant capacity, and quality of tomato fruit. The different concentrations of Se and Cu NPs were applied to the substrate every 15 days (five applications). The yield was determined until day 102 after the transplant. Non-enzymatic and enzymatic antioxidant compounds were determined in the leaves and fruits as well as the fruit quality at harvest. The results indicate that tomato yield was increased by up to 21% with 10 mg L−1 of Se NPs. In leaves, Se and Cu NPs increased the content of chlorophyll, vitamin C, glutathione, 2,2′-azino-bis(3-ethylbenzthiazolin-6-sulfonic acid (ABTS), superoxide dismutase (SOD), glutathione peroxidase (GPX) and phenylalanine ammonia liasa (PAL). In fruits, they increased vitamin C, glutathione, flavonoids, firmness, total soluble solids, and titratable acidity. The combination of Se and Cu NPs at optimal concentrations could be a good alternative to improve tomato yield and quality, but more studies are needed to elucidate their effects more clearly.

Selenium deficiency inhibits micRNA-146a to promote ROS-induced inflammation via regulation of the MAPK pathway in the head kidney of carp

Selenium (Se) is a necessity in multiple species of fish. Se plays an important role in immunoregulation, inflammation, and antioxidant systems in fish and other animals. The head kidney is the major immune organ in adult carp, and it produces white blood cells and destroys old red blood cells. The present study aimed to explore the effects and regulatory molecular mechanisms of Se on ROS and micRNA-146a as part of the inflammatory response in fancy carp. Adult fancy carp were fed different concentrations of Se in their diets. The Se content of the head kidney changed in a pattern consistent with the dietary content of Se. Se deficiency induced a significant increase in ROS, restrained the activities of GPx, SOD and CAT and increased MDA content. qPCR analysis showed a reduction in micRNA-146a with Se deficiency. The Se content, miRNA-146a expression and ROS levels were correlated. H2O2 cell stimulation assays found that ROS could activate the MAPK pathway, and ELISA results showed p38, JNK and ERK phosphorylation significantly increased with H2O2 stimulation. TNF-α, IL-1β, and IL-6 were appreciably increased. At same time, miRNA-146a, which should have increased to regulate the inflammatory response, was reduced with Se deficiency. Therefore, with Se deficiency, the head kidney was inflamed. All these results indicated that Se deficiency inhibits micRNA-146a to promote ROS-induced inflammation via regulating the MAPK pathway in the head kidney of carp. The present study revealed that supplementing the diet of carp with selenium is beneficial for growth and disease prevention.

Effect of Dietary Selenium Supplementation on Growth and Reproduction of Silkworm Bombyx mori L.

The effects of selenium (Se) on the growth and reproduction of the Lepidoptera insect, the silkworm, Bombyx mori L were investigated. Initially, the silkworms were divided into eight groups (150 larvae/group) on the basis of feeding with mulberry leaves saturated with different concentrations of Se (25, 50, 100, 125, 150, 175, and 200μM) and control from the first day of the fourth instar larvae. After feeding, growth and reproductive performance of B. mori L. were investigated with standard techniques used in sericulture. After the data analysis, 50μM of Se was recognized as the optimal level which positively influenced the growth and production, with prolonged stage of larvae, increased larval, cocoon, and pupal weights, and enhanced number of eggs laid by the female moth as compared to the control group. On the contrary, 200μM of Se treatment displayed toxic to silkworm and induced significant decrease in the growth, cocoon production, and reproduction. The weight of the cocoon shell, the cocoon shell ratio, number of eggs produced, and fertilization ratio in all the Se-treated groups were lower than the control group. The present study indicated that lower levels of (50μM) of Se can promote the larval and pupal growth of the B. mori L. resulting in the higher yield of cocoon crop and significantly influencing the fecundity, while high concentration was toxic to silkworm. Our data supply the novel application of Se which could be highly beneficial to sericulture farmers.

Mechanism Underlying the Protective Effect of Selenium on NO-Induced Oxidative Damage in Bovine Mammary Epithelial Cells.

This experiment was conducted to investigate the effects and mechanism of selenium (Se) on antioxidant and immune function of bovine mammary epithelial cells (BMEC) damaged by nitric oxide (NO). The third-generation BMEC was randomly divided into eight treatments with six replicates. The BMEC in the control group was cultured in the medium without Se and diethylenetriamine/NO (DETA/NO) for 30h. For the DETA/NO group and Se protection group BMEC were exposed to different concentrations of Se (0, 10, 20, 50, 100, 150, and 200nmol/L) for 24h, followed by treatment with DETA/NO (1000μmol/L) for 6h. Compared with the control group, DETA/NO decreased proliferation rate and activity of thioredoxin reductase (TrxR; P < 0.05). Additionally, DETA/NO decreased the gene expression of both nuclear factor-E2-related factor 2 (Nrf2) and TrxR, as well as the protein expression level of TrxR. However, the activity, and expression levels of inducible nitric oxide synthase (iNOS), as well as the concentration and gene expression level of interleukin-1β (IL-1β) and the concentration of NO significantly increased (P < 0.05). The gene expression levels of indexes related to the mitogen-activated protein kinase (MAPK) signaling pathway showed similar changes. Treatment of BMEC with Se significantly reversed DETA/NO-induced changes in a linear or quadratic dose-dependent manner (P < 0.05), with greatest benefit at 50nmol/L. These data suggests that Se improves the antioxidant function of BMEC, and protects cells from DETA/NO-induced oxidative damage, primarily by enhancing the activity of TrxR and decreasing the concentration of NO through modulation of Nrf2 and MAPK signaling pathways.

Seed exudates of Sesbania virgata (Cav.) Pers. stimulate the asymbiotic phase of the arbuscular mycorrhizal fungus Gigaspora albida Becker &amp; Hall

ABSTRACT Sesbania virgata is a legume used in the restoration of degraded areas and forms a symbiosis with arbuscular mycorrhizal fungi (AMF). Its seeds exude secondary metabolites that may influence the colonization by AMF. In this work, we studied the effects of seed (SE) and root exudates (RE) of S. virgata on the asymbiotic phase of Gigaspora albida. Spores of G. albida were germinated in medium supplemented with different concentrations of SE or RE. After seven days, spore germination was stimulated (46.6%) in the medium supplemented with the highest concentration of SE, while the mycelial growth was stimulated with the lowest SE concentration. In turn, RE had no effect on the fungal asymbiotic phase. We concluded that SE exert a positive effect on the asymbiotic phase of G. albida and that the different effects between SE and RE of S. virgata can be explained by their distinct content of secondary metabolites.