Se Accumulation Research Articles

Mineralogical features and physicochemical formation conditions of vein mineralization of the southern fank of the Saf'yanovka massive sulfde deposit (Central Urals)

The paper presents the results of studies of sulfde and fuorite veins of the southern fank of the Saf'yanovka massive sulfde deposit, Central Urals. The sulfde veins include sphalerite-galena and sphalerite-pyrite-chalcopyrite types, in which sulfdes are associated with gypsum, carbonates, barite or quartz. Fluorite in host rocks is closely related to carbonates (dolomite, calcite, and siderite), kaolinite and magnesiocarpholite. The sulfde veins differ in chemical composition and rare minerals. In galena-sphalerite veins, the higher Zn, Pb, Cd and Ag content is associated with the presence of sphalerite, galena and tennantite-(Zn) with Ag (up to 1.09 wt %). In sphalerite-pyrite-chalcopyrite veins, the accumulation of Cu, Sn, In, Se, Te and Bi is explained by the presence of tennantite-(Zn), enargite, stannoidite, sakuraiite (?), wittichenite, hessite and Se-bearing galena. The elevated (ppm) Th (1.69) и U (4.79) and REE + Y (447) content is determined in fuorite veins. The REE minerals include fuorcarbonates (synchisite-(Nd) (predominant), synchisite-(Y), synchisite-(Ce) and bastnasite), which are closely associated with overprinted dolomite and kaolinite. The fuid inclusions study of gypsum from pyrite-chalcopyrite veins showed that the associated Cu mineralization formed from H2O-Na-K chloride fuid at temperatures of 210–150 °С. The fuid, which was responsible for the formation of fuorite veins, contained Na, K, Ca и Mg. The formation temperatures of fuorite range from 190 to 280 °С. New data revealed the peculiarities of mineral composition of rich Cu ores with fuorite and also explain the higher content of some elements, including REEs.

Selenium Improves the Nutritional and Antioxidant Properties of Oregano (Origanum vulgare L.) Grown in Hydroponics

Oregano (Origanum vulgare L.) is one of the most commercially popular aromatic spices which has long been used in folk medicine as a medicinal plant due to the presence of a wide group of bioactive secondary metabolites. The experimental data available to date indicate that plants of individual species within the Lamiaceae family implement different strategies for the absorption and distribution of selenium (Se) and differ in their metabolic response to Se treatment. In this regard, the present study investigated the effect of Se application (in the form of sodium selenate) at various concentrations (2.0, 5.0, 10.0, 20.0, and 40.0 μM) on the growth and accumulation of Se in oregano plant shoots and roots, as well as on nutritional components and secondary metabolites in shoots. The addition of Se to the nutrient solution at concentrations of 2–20 μM did not adversely affect the growth and accumulation of biomass in the oregano plants, which were characterized by a significant ability to transfer Se from roots to shoots (the translocation factor was >2). The Se treatment enhanced the nutritional proprieties of the oregano and, particularly, it stimulated the accumulation of carbohydrates and proteins (by 30 and 17%) and minerals (calcium and manganese). The total contents of phenolic compounds, flavonoids, hydroxycinnamic acids, luteolin-7-glucoside and its derivatives, catechin, 3,4-dihydroxybenzoic acid, rosmarinic acid and oleanolic and ursolic acids, as well as the percentage of essential oil, showed a dose-dependent increase in the oregano under the Se treatment. Changes in the relative content of the four main components of oregano essential oil (sabinene, germacrene D, β-caryophyllene, and (Z)-β-ocimene) under the Se treatment were not significant. The relative proportions of β-caryophyllene oxide and terpinen-4-ol increased with Se concentration augmentation in the nutrient solution. The obtained results indicate the prospect of using Se at 5–20 μM concentrations in nutrient solution in hydroponically grown oregano to produce Se-biofortified plants with higher levels of compounds beneficial to health and antioxidant activity without yield reduction.

Efficiency of Biofortification with Zn and Se in Soybean: Yield and Overall Mineral Content in Plant

Since plant’s edible parts are one of the most important sources of nutrition, agronomic biofortification plays a huge role in overcoming mineral deficiency worldwide. The field-based research trial was set up in 2 years (2020 and 2021) with seven different treatments of foliar Zn and Se biofortification: 1. control (without Se or Zn solutions); 2. Se_1 treatment: 10 g/ha Se; 3. Se_2 treatment: 20 g/ha Se; 4. Se_3 treatment: 30 g/ha Se; 5. Zn_1 treatment: 3 kg/ha Zn; 6. Zn_2 treatment: 6 kg/ha Zn; 7. Se_3 Zn_2 treatment: 30 g/ha Se + 6 kg ha Zn. There were six soybean varieties of the 00 to I maturity group (Ika, Korana, Lucija, Sonja, Sunce, and Toma) included in the study, which originated from the Agricultural Institute Osijek, Croatia. After sampling the plants at the harvest, the macro- and micronutrient status in the grain, pods, leaves, and stems were determined, as well as nutrient removal by the plant. In general, biofortification treatment has a very significant influence (p < 0.001) on both Zn and Se accumulation in soybean grain and the removal of the elements within all above-ground organs. The highest increments of Zn in the soybean grain were determined at the Zn_2 treatment, which was 43% higher than the control treatment. The Toma variety accumulates the highest Zn in the grain (61.47 mg/kg), and the Lucija variety accumulates the highest Se (1070.71 µg/kg). The Se content in the soybean grain was the highest at the Se_3 treatment, where it was 53 times higher compared to the control. The linear regression showed that for each kg Zn and g Se applied, the grain status increased by 3.18 mg/kg and 338.71 µg/kg, respectively. The highest Zn nutrient use efficiency (NUE) of foliar biofortification for grain (2.6%) and vegetative mass (4.4%) was with 3 kg/ha (Zn_1). Generally, for all the Se treatments, it was found that the seed and vegetative mass yields of 4.0 t/ha have average Se NUE, around 38%, and vegetative mass of around 6%.

Concentration of Chemical Elements in the Leaves of the <i>Salix miyabeana</i> Seemen, Growing in the Area of the Tailings Dam of the Darasun Gold Deposit

In the area of the tailings dam of the Darasun gold deposit in the Trans-Baikal Territory, the content of 47 chemical elements in the leaves of the Miabe willow (Salix miyabeana), as well as their gross content in the soil in places where plants grow, were studied to obtain information about the accumulation of elements by the plant on contaminated soils and the prospect of using Miabe willow as a phytoextractor plant. The analysis of plant and soil samples was carried out on an ICP-MS Elan 9000 mass spectrophotometer (Canada). The method of measuring the metal content in solid objects by the ISP-MS method was used. It was found that the gross content of Ag, Pb, Cd, Cu, Zn, W, Hg, B and especially Te, Bi, As and Sb in the soil was 2–840 times higher than the clark of the Earth’s crust. The total content of As, Zn, Pb, Sb and Cd in the soil was 1.3–7.0 times higher than the maximum permissible concentrations (MPC) and approximately permissible concentrations (APC) of chemicals, and the arsenic content exceeded the established limit by 240 times. The concentration of K, Sr, Ti, P, Zn, Ag, As and Cd in the leaves of the Miabe willow exceeded the clark of terrestrial plants by 1.5–3.0 times. A correlation was found between the concentration of Cd, Zn, B, Mn, Be, Ga and V in the leaves of the Miabe willow with the gross content of these elements in the soil of the plant’s growing sites. The storage elements in the plant were Se, P, Cd, Zn, B and K. The coefficient of biological accumulation of Se ranged from 1 to 40, Cd – 1.1–5.8, Zn – 0.5–2.6. Miabe willow is a promising plant for extracting cadmium and zinc from contaminated soils.

Effects of elevated CO2 concentration on Se accumulation and associated rhizobacterial community in Cardamine hupingshanensis

Effects of elevated CO2 concentration on Se accumulation and associated rhizobacterial community in Cardamine hupingshanensis

Selenium Occurrence Characteristics and Bioavailability of Soil in the Hinterland of the Hetao Plain

In order to find out the influencing factors of soil selenium （Se） and bioavailability of Se, 1985 soil samples and 120 sets of crop and root soil samples were collected in the hinterland of the Hetao Plain, and the characteristics of soil Se, different forms of Se, and crop Se and heavy metal content were analyzed. The results showed that approximately 5.59% of soil samples exceeded the risk screening values for soil contamination of agricultural land of GB15618-2018 standard, but the heavy metal content in crops was much lower than the standard value, suggesting that the overall risk of heavy metal pollution was low. Se had significant autocorrelation in soil and appeared enriched locally, which were mainly related to natural factors. The content of different forms of Se in root soil was ranked as： residue state > humic acid state > water soluble state ≈ strong organic state > carbonate state > ion exchange state > iron and manganese oxidation state, this result showed that the characteristics of Se in root soil were high availability state, high potential availability state, and low unavailability state compared with those of most areas in China. At the same time, the results showed that water-soluble, ion exchange, and carbonate Se of root soil were significantly correlated with Se of crops,indicating that they were effective forms that could be absorbed and utilized by plants. According to the Se content and bioconcentration factor, different crops were ranked as： white melon seeds > sunflowers > corn. By means of cluster analysis and correlation analysis, the factors affecting the total Se and bioavailability of Se in soil were studied. It was concluded that soil texture, organic matter, and pH had opposite effects on Se and bioavailability of Se in soil. Factors such as clay soil, high organic matter, and low pH degree could promote the accumulation of Se in soil but also limited the activity of available Se. Based on crop and root soil sample data, the soil Se enrichment threshold was discussed. The results demonstrated that using "ω（total Se）≥0.222 mg·kg-1" as the threshold, the proportion of soil Se enrichment was closer to the Se enrichment level of crops than others.

Effect of Paenibacillus favisporus CHP14 inoculation on selenium accumulation and tolerance of Pakchoi (Brassica chinensis L.) under exogenous selenite treatments

The effects of Paenibacillus favisporus CHP14 inoculation on selenium (Se) accumulation and Se tolerance of Pakchoi were studied by a pot experiment conducted in greenhouse. The results revealed that the growth traits such as plant height, root length, and biomass were significantly elevated during CHP14 treatment at 0 ∼ 8.0 mg·kg−1 Se(IV) levels. CHP14-inoculated plants accumulated more Se in root and shoot, which were 24.1%∼57.3% and 7.5%∼50.9% higher than those of non-inoculated plants. The contents of leaf nitrogen (N), phosphorus (P), magnesium (Mg), and iron (Fe), as well as the ratio of indoleacetic acid and abscisic acid contents (IAA/ABA) were increased by CHP14 inoculation, and positively associated with photosynthetic pigment contents (p < 0.05). At ≥ 4.0 mg·kg−1 Se(IV) levels, superoxide dismutase, peroxidase, and glutathione peroxidase activities of Pakchoi roots were increased with CHP14 inoculation, by 9.9%∼17.1%, 28.4%∼40.7%, and 7.4%∼15.3%, respectively. Moreover, CHP14 inoculation enhanced ascorbate-glutathione (AsA-GSH) metabolism in roots by upregulating the related enzymes activities and antioxidant contents under excess Se(IV) stress. These findings suggest that CHP14 is beneficial to improve plant growth and enhance Se(IV) resistance of Pakchoi, and can be exploited as potential inoculants for phytoremediation process in Se contaminated soil.

Impact of chickpea biofortification on the bioaccessibility of micronutrients and their relationship to obesity-linked biological activities

Micronutrient deficiencies are a critical factor in the development of obesity. This work aimed to determine the Se and Zn bioaccessibility on biofortified chickpea flour and evaluate their impact on the antioxidant and anti-inflammatory activities. The greatest increase (235 %) in isoflavones was observed in the ZnSO4-treatment compared to the control. Malonylated-formononetin-glucoside was the major isoflavone (43 %–50 %) found in the treatments. Na2SeO3-treated seeds showed the highest Se accumulation, while the greatest Zn accumulation was found in ZnSO4-treated seeds. Se bioaccesibility followed the order: Germinated Control>ZnSO4 > ZnSeO3 > ZnSO₄ + Na2SeO3 > Na2SeO3, while in the seeds biofortified with Zn salts showed the order: Germinated Control>ZnSeO3 > ZnSO₄ + Na2SeO3 > Na2SeO3 > ZnSO4. All treatments showed antioxidant activity. Na2SeO3-treatment (15.625 μg/mL) showed a significant reduction of 52 % in NO production compared to the Germinated Control. These findings demonstrated the biological value of food biofortification in providing minerals in the diet to combat the oxidative stress characteristic of obesity.

Identification, characterization, and expression analysis of WRKY transcription factors in Cardamine violifolia reveal the key genes involved in regulating selenium accumulation

BackgroundCardamine violifolia is a significant Brassicaceae plant known for its high selenium (Se) accumulation capacity, serving as an essential source of Se for both humans and animals. WRKY transcription factors play crucial roles in plant responses to various biotic and abiotic stresses, including cadmium stress, iron deficiency, and Se tolerance. However, the molecular mechanism of CvWRKY in Se accumulation is not completely clear.ResultsIn this study, 120 WRKYs with conserved domains were identified from C. violifolia and classified into three groups based on phylogenetic relationships, with Group II further subdivided into five subgroups. Gene structure analysis revealed WRKY variations and mutations within the CvWRKYs. Segmental duplication events were identified as the primary driving force behind the expansion of the CvWRKY family, with numerous stress-responsive cis-acting elements found in the promoters of CvWRKYs. Transcriptome analysis of plants treated with exogenous Se and determination of Se levels revealed a strong positive correlation between the expression levels of CvWRKY034 and the Se content. Moreover, CvWRKY021 and CvWRKY099 exhibited high homology with AtWRKY47, a gene involved in regulating Se accumulation in Arabidopsis thaliana. The WRKY domains of CvWRKY021 and AtWRKY47 were highly conserved, and transcriptome data analysis revealed that CvWRKY021 responded to Na2SeO4 induction, showing a positive correlation with the concentration of Na2SeO4 treatment. Under the induction of Na2SeO3, CvWRKY021 and CvWRKY034 were significantly upregulated in the roots but downregulated in the shoots, and the Se content in the roots increased significantly and was mainly concentrated in the roots. CvWRKY021 and CvWRKY034 may be involved in the accumulation of Se in roots.ConclusionsThe results of this study elucidate the evolution of CvWRKYs in the C. violifolia genome and provide valuable resources for further understanding the functional characteristics of WRKYs related to Se hyperaccumulation in C. violifolia.

Foliar application of microbial nano-selenium enhances selenium uptake and alleviates oxidative stress

Selenium (Se) is an essential micronutrient to humans and animals in diet primarily from edible crops. However, limited studies have been conducted on applying microbially synthesized Se nanoparticles (BioSeNPs) to affect plant Se uptake and toxicity. The bacterium Bacillus wiedmannii ES2–45 was able to efficiently produce BioSeNPs by completely reducing 5 mM selenite [Se(IV)] within 24 h. Then, fermented BioSeNPs were sprayed on the leaf surface of Brassica rapa L to investigate their effects on growth and Se accumulation. Total Se and leaf biomass increased significantly by 124 % and 14.3 % respectively in the BioSeNP treatment compared to the Se(IV) treatment. The Se(VI) treatment was found to be toxic to the leaves although Se(VI) had similar effects to BioSeNP treatments. Notably, BioSeNP treatment significantly increased the plant’s ability to alleviate oxidative stress including levels of chlorophyll, malonaldehyde (MDA), and catalase (CAT) (P<0.05). In conclusion, the foliar application of BioSeNPs is a promising strategy to improve the Se content of vegetables and alleviate Se-induced oxidative stress.

Effect of dietary supplementation of selenium-L-methionine on growth, antioxidant capacity and resistance to nitrite stress of spotted seabass (Lateolabrax maculatus) under two rearing water temperatures

A 10-week feeding trial, followed by 24-h nitrite stress, was performed to evaluate the effects of dietary selenium-L-methionine (Se-Met) on growth, Se accumulation, antioxidant capacity, transcripts of selenoproteins and histological changes of muscle as well as resistance to nitrite stress in spotted seabass (Lateolabrax maculatus) reared at optimal (27 °C) and high (33 °C) temperatures. Five experimental diets were formulated to contain 0, 0.9, 1.8, 3.5, and 7.0 mg Se-Met/kg. Each diet was fed to fish (2.60 ± 0.2 g) in two parallel treatments at 27 or 33 °C. The results showed that elevated temperature (33 °C) induced thermal stress in fish, and fish under thermal stress exhibited lower weight gain and hepatosomatic index but a higher condition factor compared to those reared at 27 °C. However, the growth and feed utilisation were promoted in L. maculatus with 0.9 to 3.5 mg/kg Se-Met treatments. The protein and lipid content in the muscle increased with the dietary Se-Met level, and the total Se level in the whole body and muscle showed a linear increase with dietary Se-Met supplementation. Thermal stress changed the histology of the muscle, leading to raised levels of malondialdehyde (MDA), reduced antioxidant parameters in the serum and liver, and a decrease in the transcripts of selenoprotein genes in the muscle. Meanwhile, increased antioxidant capacity of serum and liver and up-regulated transcripts of selenoprotein of muscle were observed in L. maculatus reaching a maximum with 3.5 mg Se-Met/kg treatment. After 24 h of nitrite stress, thermal stress exacerbated oxidative damage caused by nitrite stress in L. maculatus. In contrast, dietary Se-Met enhanced the resistance to nitrite stress of L. maculatus fed with Se-Met enriched diets containing 0.9 to 1.8 mg Se-Met/kg. Based on the effects of dietary Se-Met on the growth, antioxidant capacity and resistance to nitrite stress of L. maculatus, this study suggests that the optimal range of Se-Met supplementation in L. maculatus diets is 1.80 to 2.39 mg Se-Met/kg of diet at 27 °C and 1.80 to 4.46 mg Se-Met/kg of diet at 33 °C.

Characteristics of Soil Selenium-cadmium Migration and Accumulation and Its Bioeffectiveness in Typical Geological High Background Area

The prevalence of selenium-cadmium （Se-Cd） symbiosis in soils of geologically high background areas directly affects the safe utilization of Se-rich land resources. To investigate the migration and accumulation characteristics and bio-effectiveness of Se-Cd in the soil-crop system in typical geological high background areas of Southwest China and to realize the safe use of natural Se-rich land resources in geological high background areas, we collected 84 samples of agricultural crops （maize） and their supporting root systems and analyzed the Se-Cd content and physicochemical properties. Se-Cd accumulation characteristics, influencing factors, and bio-effectiveness of the soil-crop system were evaluated using geostatistics, bioenrichment factors, and geographic detectors. The results showed that the Se-Cd content in the study area was significantly higher than the background value of the soil in the whole country and in Yunnan Province. Influenced by the geological background, secondary enrichment in the process of soil formation, and agricultural activities, the accumulation and enrichment characteristics of Se in the root soil varied from no enrichment to slightly enriched, and the occurrence form was dominated by the residue state. The accumulation index of soil Cd was mainly in the medium pollution level, and the occurrence form was mainly in the residual state and the combined state of iron and manganese. The Se-enrichment rate of crop seeds reached 98.8% （DB 50/T 524-2013 standard）, and the average value of bioconcentration factor was 5.8%. The exceeding rate of Cd content in crop seeds was only 1.19% （GB 2762-2022 standard）, and the average value of Cd bioconcentration factor was 2.11%, so the ecological risk of heavy metal Cd in crop seeds was relatively low. In the Se-Cd symbiosis area under geological background, the weak alkaline environment of the soil could effectively reduce the bioavailability of Cd in crop seeds, and the Se-rich soil could inhibit the uptake of Cd by the crops to a certain extent. Correlation analysis showed that the migration and accumulation of Se and Cd from soil to crop seeds in the soil-crop system were affected by the elemental accumulation pattern and the physical and chemical properties （pH） of the soil, and at the same time, there was a certain synergistic-antagonistic effect between Se and Cd in the soil-crop system. Correlation analysis showed that the migration and accumulation of Se and Cd from soil to crop seeds in the soil-crop system was influenced by the occurrence of elements, soil physicochemical properties （pH）, and other factors, and there was also a certain synergistic-antagonistic interaction between Se and Cd in the soil-crop system.

Effects of Foliar Application of Nano-Se on Photosynthetic Characteristics and Se Accumulation in Paeonia ostii

Effects of Foliar Application of Nano-Se on Photosynthetic Characteristics and Se Accumulation in Paeonia ostii

Efficacy and selenium enrichment of Lycium barbarum in hydroponic and soil conditions in the Ararat valley

Background: It is known that 60-80% of the population affected by various diseases, such as heart attack, stroke, and oncological diseases is associated with selenium (Se) deficiency. Therefore, enriching agricultural crops with Se is considered a current issue. Objective: This study investigates Se enrichment of Lycium barbarum (Lb) and its effectiveness in hydroponic and soil conditions in the Ararat Valley. The research focuses on the impact of adding exogenous Se on plant productivity, Se accumulation, and the content of biologically active substances (BAS) in Lb berries and leaves. Methods: The experiments were conducted from 2021 to 2023 using hydroponic and soil cultivation methods with varying Se concentrations in nutrient solutions and foliar nutrition. Results: The results demonstrate that Se enrichment significantly increased Se and BAS levels in both leaves and berries of Lb, with hydroponic cultivation exhibiting higher accumulation compared to soil conditions. Foliar feeding with a 0.005% Se solution and exogenous Se addition to nutrient solutions at 1.0 mg/L resulted in notable improvements in Se content and plant productivity. Furthermore, the analyses revealed significant differences between hydroponically and soil-grown Lb, emphasizing the potential of hydroponic cultivation for producing Se-enriched plant material with enhanced BAS content. Conclusion: Hydroponic cultivation supplemented with Se and foliar nutrition is recommended for obtaining Se-rich Lb plant material, which is suitable for medicinal and functional food purposes. These findings contribute to the development of biotechnologies for Se -enriched plant production and addressing health and nutritional needs. Keywords: Goji, berries, biologically active substances, flavonoids, phenolic acids, tannins, carotenoids

The dynamics of heavy metals and metalloids accumulation in oxbow bottom sediments of the Sok River

The article analyzes the dynamics of heavy metals (V, Cr, Mn, Co, Ni, Cu, Zn, Rb, Sr, Cd, Pb) and metalloids (As, Se) accumulation in the bottom sediments of the low-flow oxbow of the Sok River. This oxbow was formed as a result of the Saratov reservoir creation and located within the Krasnoglinsky District of the Samara city. The study was conducted in 2021 and 2022. Four trial plots were established in the oxbow of the river; the control plot was a sample area allocated in the Saratov reservoir, in the immediate vicinity of the oxbow. The quantitative determination of heavy metals and metalloids content in bottom sediments was carried out using inductively coupled plasma spectrometry. The results obtained showed that specific conditions arise in each research period that affect the studied elements accumulation in the oxbow bottom sediments. These processes are influenced by the location of the sample plot in the oxbow, the flow degree, the spring flood nature, the anthropogenic transformation and the overgrowth of Typha angustifolia L. For all sample plots located in the oxbow, higher concentrations of most of nalyzed elements were detected in 2022. Heavy metals and metalloids accumulated especially actively in the bottom sediments of sample plot 4, located in the oxbow behind an artificial dam and characterized by the weakest flow. The soil cover of Samara city posesses weak and moderate effect on the quantitative characteristics of metal accumulation in the oxbow bottom sediments. Compared to the control, the studied elements accumulated more actively in the bottom sediments of all oxbow sample areas, which confirms the accumulative nature of river oxbow of varying degrees of isolation.

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.

Accumulation and metabolism of selenium in the rare yeast Kazachstania unispora during the selenium enrichment process

Selenium (Se)-enriched yeast is a good nutritional source for human being. Kazachstania unispora (K. unispora) has shown the positive physiological functionality for human health, whose potential for Se enrichment, however, remains elusive. This study demonstrated the ability of K. unispora to convert inorganic Se to organic Se, and then comprehensively investigated the accumulation and metabolism of Se in K. unispora. The results indicated that K. unispora can effectively accumulate organic Se, of which 95% of absorbed Se was converted to organic forms. Among these organic Se, 46.17% of them was bound to protein and 16.78% was combined with polysaccharides. In addition, some of the organic Se was metabolized to selenomethionine (30.26%) and selenocystine (3.02%), during which four low-molecular weight selenometabolites were identified in K. unispora. These findings expand the scope of Se-enriched yeast species, and provide useful knowledge for further investigation of Se enrichment mechanism in K. unispora.

Ionomic Profile of Rice Seedlings after Foliar Application of Selenium Nanoparticles.

Nanotechnology has been increasingly used in plant sciences, with engineered nanoparticles showing promising results as fertilizers or pesticides. The present study compared the effects in the foliar application of Se nanoparticles (SeNPs) or sodium selenite-Se(IV) on rice seedlings. The degree of plant growth, photosynthetic pigment content, and concentrations of Se, Na, Mg, K, Ca, Mn, Co, Cu, Zn, As, Cd, and Pb were evaluated. The results showed that the application of SeNPs at high concentrations (5 mg L-1), as well as the application of Se(IV), inhibited plant growth and increased the root concentrations of As and Pb. The application of SeNPs at 0.5 mg L-1 significantly increased Se accumulation in the aerial part from 0.161 ± 0.028 mg kg-1 to 0.836 ± 0.097 mg kg-1 without influencing physiological, chemical, or biochemical parameters. When applied to leaves, SeNPs tended to remain in the aerial part, while the application of Se(IV) caused a higher Se translocation from the shoots to the roots. This study provides useful information concerning the uptake, accumulation, and translocation of different Se formulations in rice seedlings and their effect on plant ionomic profiles, thus showing that the foliar application of SeNPs at low concentrations can be an effective and safe alternative for rice biofortification.

Bioaccessibility of trace elements and Fe and Al endogenic nanoparticles in farmed insects: Pursuing quality sustainable food

This study investigated the in vitro bioaccessibility of aluminum, copper, iron, manganese, lead, selenium, and zinc in three important species of farmed insects: the yellow mealworm (Tenebrio molitor), the house cricket (Acheta domesticus) and the migratory locust (Locusta migratoria). Results show that all three insect species constitute excellent sources of essential elements (Fe, Cu and Zn) for the human diet, contributing to the recommended dietary allowance, i.e., 10%, 50%, and 92%, respectively. A higher accumulation of Se (≥1.4 mg Se/kg) was observed with increasing exposure concentration in A. domesticus, showing the possibility of using insects as a supplements for this element. The presence of Al and Fe nanoparticles was confirmed in all three species using single particle-inductively coupled plasma-mass spectrometry and transmission electron microscopy. The results also indicate that Fe bioaccessibility declines with increasing Fe-nanoparticle concentration. These findings contribute to increase the nutritional and toxicological insights of farmed insects.

Application of 2-Iminoselenazolidin-4-Ones (ISeA) for Beta vulgaris L. and Brassica rapa L. Plants Se-Biofortification

Due to widespread selenium deficiency in food the aim of this study was to evaluate the effectiveness of a new Se(II)-containing organic chemical compound 2-iminoselenazolidin-4-ones (ISeA) in the form of a nanoscale associate (1–5 nm) solution for Swiss chard and komatsuna plants biofortification. Application of the chosen substance as a foliar treatment (2 mg·L−1) and as an additive to a hydroponic nutrient solution (10 mg·L−1) was performed. Both cultures had a high level of Se absorption, distribution and accumulation in leaves two or more times greater than in petioles. Se content in chard petioles (15 mg·L−1) when applying ISeA as a component of the nutrient solution exceeded the accumulation of Se during foliar treatment (9.6 mg·L−1) and the same trend in the komatsuna leaves was observed. When applying ISeA to the nutrient solution, an increase in komatsuna and chard biomass was seen at 36 and 68% and for leaf treatment by 21 and 45%, respectively. For komatsuna and chard an increase in the ratio of dry to fresh weight was also observed to be 27 and 26%, and for foliar treatment—0 and 16%, respectively. Treatments led to increase in chard plants height (7–17%), enlargement of leaves (19–42%), a rise in photosynthetic pigments (20–60%) and anthocyanin (2.9 and 2.2 times) concentration, and for komatsuna—the multiplication of leaves number (28%) and their surface area (27–29%) as well as a rise in the concentration of anthocyanin (1.0 and 1.6 times) with foliar treatment and nutrient solution enrichment.