Amounts Of Selenium Research Articles

Assimilation of Selenium, Copper, and Zinc in Rye Malt

Abstract Trace elements selenium, copper, and zinc are essential minerals for the human body. One of the means to increase the micronutrient content in diets is to add them to food raw materials, for example, to enrich grain with micronutrients during malt production. To obtain rye malt, 3 kg grain was soaked in 10 l water with addition of three mineral salts — sodium selenate (Na2SeO4), copper sulphate (CuSO4 5H2O), and zinc sulphate (ZnSO4 7H2O) at different concentrations and different combination of salts. The concentration of selenium, copper, and zinc was determined in rye malt. The obtained results were used to calculate the degree of assimilation of trace elements in rye malt. The interaction of trace elements selenium/copper and copper/zinc was studied. The total amount of selenium, copper, and zinc was analysed by inductively coupled plasma mass spectrometry (ICP-MS). Sample preparation for elemental analysis was performed by wet acid digestion in a closed microwave mineralisation system. The selenium assimilation degree in rye malt was within 10.6 to 12.2%. Accordingly, copper assimilation was 32.8 to 38.0% and zinc 49.3 to 57.0%. Simultaneous presence of selenium/copper and copper/zinc during rye grain soaking promoted the assimilation of each mineral, compared with only one mineral additive.

Endoplasmic Reticulum Stress Drives High Selenium‐Induced Endothelial Dysfunction

BackgroundSelenium is an essential trace element important to human health. Nonetheless, supra‐nutritional selenium intake is reported to be associated with insulin resistance and may therefore increase the risk of diabetes and disrupt endothelial function (ED), the initial step in atherosclerosis development. However, the underpinning molecular mechanisms are not clear. High selenium concentrations cause apoptosis in cancer cells through the induction of endoplasmic reticulum (ER) stress, a mechanism also involved in the pathogenesis of ED. Therefore, we hypothesised here that high selenium intake could cause ED through the activation of ER stress response.MethodsHuman Umbilical Vein Endothelial Cells (HUVECs) were cultured with selenite at either physiological (0.5μM) or supra‐nutritional concentrations (5–20μM) for 8 to 24 hours in the presence or absence of a chemical chaperone, 4‐phenylbutryic acid (PBA). Then, mRNA expression of key ER stress response markers was analysed by qPCR. To assess endothelial function, we evaluated NO (Griess assay) release and Reactive Oxygen Species (ROS, flow cytometry) production. Finally, apoptosis (flow cytometry) and caspases 3/7 activity were measured.ResultsHigh selenium concentrations (5–20μM of selenite) compared to physiological concentration (0.5μM) or control enhanced mRNA expression of several ER stress markers such as CAAA/enhanced‐binding homologous protein (CHOP) [control (2.25±0.88), 0.5 μM (3.9±0.85), 10μM (36.2±6); n=5]. The pre‐incubation of cells with PBA completely reversed high selenium‐mediated ER stress. High selenite (5–20μM) also reduced NO production [control (2.27±0.07), 0.5μM (2.4±0.04), 10μM (1.8±0.05); n=5] and enhanced ROS production [control (18.9±1.93), 0.5μM (21.7±2.14), 10μM (68±0.65); n=5] compared to physiological concentration of selenite while cells pre‐treated with PBA were fully protected. Finally, supra‐nutritional concentrations of selenite increased the percentage of apoptotic HUVECs [control (2.96%±0.94), 0.5μM (3.92%±0.85), 10μM (43.7%±5.1); n=7] and augmented caspases 3/7 activity [0.5μM (0.45±0.08), 5μM (1.92±0.3) fold of control; n=5] compared to physiological concentration. Importantly, pre‐treatment of cells with PBA completely reversed high selenium‐mediated cell death.ConclusionsWe show here that high selenium treatment causes ED and cell death through the activation of ER stress. These results highlight the importance of a balanced selenium intake in order to achieve maximal health benefits. These findings underscore the importance to monitor cardiovascular risk development in cancer patients supplemented with high amounts of selenium as part of their chemotherapeutic intervention.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Cross-sectional Study: Relationship Between Serum Selenium and Hypertension in the Shandong Province of China.

Although selenium, which is a necessary trace element for the human body, has been considered to be beneficial to the cardiovascular system and helpful to lower blood pressure, more and more evidence shows that high amounts of selenium are a risk factor for hypertension. A random multistage sampling which included the cluster method was performed; a total of 9076 urban and rural residents between 18 and 80years old in the Shandong province of China were investigated by questionnaire, physical examination, and laboratory tests. The prevalence of hypertension was 42.1% in males and 35.3% in females. The mean (standard deviation) selenium concentration was 124.68 (36.32) μg/l in males and 119.54 (31.88) μg/l in females. After adjusting for potential confounders, logistic regression analysis showed that the highest selenium levels were associated with a risk of hypertension (OR = 1.192; 95% CI 1.009-1.407) in females, while there was no significant difference in males (OR = 1.043; 95% CI 0.864-1.259). Our findings suggest that high selenium levels in females are more likely to increase the risk of hypertension compared to similar levels in males. More attention should be paid to the metabolic mechanisms and physiological effects of selenium in females.

Effect of selenium addition on network connectivity in P2O5-CaO-MgO-Na2O glasses

A new glass system xSeO2(1-x)[40P2O5-30CaO-20MgO-10Na2O] with nominal concentration of SeO2 ranging between 0 and 20 mol% was obtained by melting method. The amount of selenium determined on samples surface is much lower than that expected according to the added SeO2 amount, and this is due first to selenium volatility during melting. The Fourier transform infrared and Raman results evidence the glass network depolymerisation induced by progressive addition of selenium. The depolymerisation effect occurs more pronounced on samples surface than in their inside, as indicated by X-ray photoelectron spectroscopy analysis with respect to the dependence of bridging and non-bridging oxygens on selenium content.

Content of inorganic elements in snails meat

Currently, there are several classifications of inorganic elements, although each has its own advantages and disadvantages. The most studied group is macroelements, because they have a significant spread in the body and serve as a function of structural elements. The trace elements perform their functions, being part of the biologically active substances, which makes it difficult to study them, since the same element, depending on the form, can have a toxic effect or be vital. The macroelements include: K, Ca, Mg, Na, S, P, Cl. The trace elements are distributed as follows: Al, B, Br, V, I, Li, Si, As, Rb, Se, F, Sr and heavy metals, namely Zn, Cr, Ge, Fe, Cd, Co, Cu, Mn, Mo, Sn, Ni, Pb. Macroelements are contained in our body in a significant amount (more than 0.01% of the body weight, in other words, their content in the body of an adult is measured in grams and even in kilograms). The trace elements are involved in all processes of life and are the catalysts of biochemical reactions. Their daily intake is less than 200 mg, and they are contained in the body in small doses (less than 0.001% of body weight). The article presents the results of our own research on the content of inorganic elements in the meat of snails of various species Helix pomatia, Helix aspersa maxima and Helix aspersa muller. It is established that fresh meat of Helix aspersa maxima snails contains the least amount of heavy metals and the highest amount of selenium. Of the 12 inorganic elements that we studied in meat of snails from trace elements, Bromus is most often kept by Helix aspersa muller snails and is 1.91 ± 0.23 mg, Selenium and Manganese from Helix aspersa maxima snails are 0.32 ± 0.01mg and 29.29 ± 0.27 respectively. In the case of heavy metals in the meat of Helix aspersa maxima, there was no evidence of flatulence at all, and the most commonly found zinc in this specimen was 27.64 ± 0.22 mg in accordance. The calcium is the most enriched meat of Snails Helix pomatia and is 12571.25 ± 304.51 mg. As for the vital calcium macroelement, most of all it enriched the meat of the grape snail Helix pomatia. Based on the foregoing, it can be concluded that the fresh meat of Helix aspersa maxima snails contains the least amount of heavy metals and can be successfully used in the relevant industries, and especially in the food industry.

A nanocomposite consisting of MIL-101(Cr) and functionalized magnetite nanoparticles for extraction and determination of selenium(IV) and selenium(VI).

A metal-organic framework nanocomposite was synthesized and applied to speciation analysis of Se(IV) and Se(VI). The sorbent is composed of MIL-101(Cr) and magnetite nanoparticles modified with dithiocarbamate. It is capably of selectively extracting Se(IV) at pH = 1.85, while Se(VI) remains in solution. The total amount of selenium can then be determined by reducing Se(VI) to Se(IV) and also extracting it. The extraction parameters were optimized by employing design-of-experiments methodology. Selenium was then quantified by electrothermal AAS. Figures of merit include (a) a 10ng·L-1 limit of detection, (b) a linear response in the 30ng·L-1 to 10μg·L-1 concentration range, and (a) a relative standard deviation of <11.5% for Se(IV). The method was validated by analyzing certified reference materials (water and tomato leaves). It was also applied to the speciation analysis of Se(IV) and Se(VI) in (spiked) water samples and of total selenium in agricultural samples. Graphical abstract Schematic of the synthesis of a metal-organic framework nanocomposite for speciation analysis of Se(IV) and Se(VI). The sorbent is composed of MIL-101(Cr) and magnetite nanoparticles modified with dithiocarbamate. Selenium can be quantified by electrothermal AAS with a 10ng L-1 detection limit.

An optical sensor for selenite determination in aqueous samples

BackgroundIn the present work, an optical sensor has been developed for the determination of selenium (IV) in aqueous samples. The optical sensor is a cellulose triacetate plasticized membrane with tri-octyl methyl ammonium chloride (Al-336) immobilized in it as an ion exchanger.MethodsThe sensor works in two steps. In the first step, a 1 × 2 cm piece of the membrane is allowed to equilibrate with a known amount of selenium (IV) solution and potassium iodide in acidic medium. During this equilibration, the iodometric reaction takes place and, I3− (tri-iodide anion) is formed which gets sorbed into the membrane due to which the colorless film changes to yellow color showing an absorption maxima at 355 nm which is a characteristic of I3−. In the second step the I3− loaded membrane is allowed to equilibrate with a solution of variamine blue dye in presence of sodium acetate. In this step, oxidation of the dye takes place and the membrane shows a color change from yellow to violet and a shift in the absorption maxima from 355 to 550 nm.ResultsThe method is used to study the quantitative determination of selenium in aqueous samples, where the amount of selenium is varied and the corresponding absorbance at 550 nm is measured. A good linear curve is obtained in the concentration range of 0.2 to 3 μg mL−1 of selenium.ConclusionsThe proposed method can be successfully applied to determination of selenium (IV) in various pharmaceutical and environmental samples.

Investigation of Blood Selenium and Zinc in Type2 Diabetes with TCF7L2 (rs7903146 C/T) Genotypes

TCF7L2 (rs7903146) as one of the most significant single nucleotide polymorphism, is one of the associated genes with type 2 diabetes. This case-control study was performed on the whole blood of 87 patients with type 2 diabetes and 45 healthy people. Selenium and zinc concentrations in whole blood were measured using flameless atomic-absorption spectrometry. The genotype of TCF7L2 was achieved by real-time PCR and high-resolution melt (HRM). In order to data analyzing, the t-test and one-way analysis of variance (ANOVA) were used. The difference of zinc levels and also selenium levels in whole blood for both healthy (Zinc: 164.75 μgr dL-1, selenium: 140.71 μgr L-1) and patients (Zinc: 136.77 μgr dL-1, selenium: 111.66 μgr L-1) groups was significant (P-value <0.05). The different levels of zinc and selenium in healthy genotype group (TT, CT, CC) and type 2 diabetic patient genotype (TT, CT, CC) group was also significant (P-value <0.05). The presence of the T allele as a risk factor led to reducing zinc levels in healthy subjects. Significant reduction in zinc in the diabetic CT versus healthy CC and in diabetic TT versus healthy CT can be considered as a result of the T allele risk. Amount of selenium in TT genotype in both control group and diabetic patients was reduced.

Speciation of selenium(IV) (selenite) and selenium(VI) (selenate) levels in human whole blood samples

This paper examined the speciation of selenium(IV) (selenite) and selenium(VI) (selenate) levels in human blood samples from Tarkwa and its environs, a mining-impacted area in Ghana, using hydride generation atomic absorption spectrophotometric technique. Selenium (IV) within the experimental subjects ranged from 0.08±0.01 μg/mL to 0.50±0.02 μg/ mL with a mean of 0.29 μg/mL, while the control ranged from 0.02±0.1 μg/mL to 0.21±0.05 μg/mL, with a mean of 0.07 μg/ mL. Significant differences existed between the amount of selenium (IV) concentrations in experimental and control subjects (p=0.0001<0.05). The selenium (VI) in experimental subjects ranged from 2.97±0.52 μg/mL to 4.39±0.42 μg/mL, with a mean of 3.63 μg/mL, while the control ranged from 0.60 μg/mL to 1.0 μg/mL, with a mean of 0.89 μg/mL. Significant differences existed between the degree of selenium (VI) in experimental and also the control subjects (p=5.98 x10-14<0.05). The measurement precision determined by relative variance was within ±5%. The accuracy of the determination was evaluated by analysing certified standard human hair reference material GBW 09101.

Experimentally Induced Selenosis in Yellow-Bellied Slider Turtles ( Trachemys scripta scripta).

Selenosis, or selenium toxicosis, occurs in wildlife and livestock, usually because of excessive intake of selenium via selenium-containing plants. Although it is known that wild slider turtles can accumulate large amounts of selenium, little is known about how selenium exposure may affect these reptiles. In this study, the authors report histopathologic changes in yellow-bellied sliders ( Trachemys scripta scripta) caused by experimental exposure to selenomethionine. Microscopic changes in kidney and claw tissue were most significant and resembled those reported in birds. Turtles in the selenium treatment groups had acute tubular degeneration and regeneration in the kidney, with hyaline droplets in the high-dose animals, and changes in the claws ranging from epidermal hyperplasia with disorganization and intercellular edema to ulceration, and accumulation of seroheterophilic exudate between the epidermis and cornified layer. Although selenium burdens in this study are comparable with values found in wild slider turtles, more data are needed to determine if similar histopathologic abnormalities arise in wild animals exposed to high levels of selenium.

Modification of polyamide films by semiconductive and conductive copper selenide–copper sulfide layers

Modification of the surface of polyamide 6 (PA) films by semiconductive and electrically conductive layers of mixed copper selenide–copper sulfide, CuxSe–CuyS, was performed using the sorption–diffusion method and the water solutions of potassium selenopentathionate, K2SeS4O6, as the precursor of polymer chalcogeniumization. Selenopentathionate anions containing divalent selenium and sulfur atoms of low oxidation state,–O3S-S-Se-S-SO3–, are sorbed-diffused into PA films if they are treated with selenopentathionate solutions. CuxSe–CuyS layers form on the surface of a PA (polyamide 6) film when a chalcogeniumized polymer is treated with a water solution of copper(II/I) salt: the anions of selenopentathionate react with copper ions. The concentration of sulfur, selenium and copper increases with an increase of the concentration and temperature of a precursor solution and the duration of PA initial chalcogeniumization. The formed layers were characterized for chemical composition, electrical and physical properties. The percentage amounts of selenium, sulfur and copper in CuxSe–CuyS layers on PA films increase with polymer chalcogeniumization time. The X–ray diffraction (XRD) pattern study of CuxSe–CuyS layers showed that they are polycrystalline in nature. The six phases of copper selenides – Cu2Se, CuSe2, CuSe2, Cu3Se2, berzellianite Cu2-xSe and bellidoite Cu2Se, also the four phases of copper sulfides – monoclinic djurleite, Cu1.9375Se, cubic digenite, Cu1.8S, orthorhombic chalcocite, Cu2S, and orthohrombic anilite, Cu1.75S, have been identified. With an increase of the concentration and temperature of the precursor solution and the duration of PA treatment the highest concentration of conductive copper selenides is reached and the composition of CuxSe phases changes in the direction of a decrease of x. XPS results confirmed the formation of copper selenides–copper sulfides layers on the surface of PA. The regularities established enable formation of CuxSe–CuyS layers of the desirable composition and conductivity. Studies by the method of atomic force microscopy (AFM) showed that depending on the conditions (duration of chalcogeniumization, concentration and temperature) of the PA initial treatment in the K2SeS4O6 solution (under the same “copperizing” conditions), the formation of copper chalcogenide layers proceeds irregularly in the form of islands which grow into larger agglomerates. The surface of the layer is uneven, rather rough.

Selenium poisoning of fish by coal ash wastewater in Herrington Lake, Kentucky

Selenium pollution from the E.W. Brown Electric Generating Station was investigated in Herrington Lake, KY. Coal ash wastewater is discharged as surface water overflow from ash disposal ponds into the lake via a National Pollutant Discharge Elimination System permit issued by the Kentucky Division of Water, but the permit does not restrict or limit the amount of selenium released. Unpermitted discharges occur from seeps and drainage through leaks in ash pond dams. Together, these discharges have resulted in selenium concentrations in water, sediment, benthic macroinvertebrates, and fish that are 2–9 times the level that is toxic for fish reproduction and survival. A large proportion (12.2%, or 25 times background) of juvenile largemouth bass (Micropterus salmoides, the only species examined) exhibited spinal and/or craniofacial malformations that are consistent with selenium poisoning. Teratogenic Deformity Index values indicated a 3.05% population-level impact on the bass fishery, with total selenium-induced mortality (including pre-swimup mortality) estimated to be in excess of 25% per year. These findings confirm that coal ash discharges into Herrington Lake are contributing selenium to the Lake that is poisoning fish.

Liečba selénom u tyreopatií

Selenium (latin Selenium) is a micronutrient embedded in several proteins. In adults, the thyroid is the organ with the highest amount of selenium per gram of tissue. Selenium levels in the body depend on the characteristics of the population and its diet and geographic area. In the thyroid, selenium is required for the antioxidant function and for the metabolism of thyroid hormones. The literature suggests that selenium supplementation of patients with Hashimotos thyroiditis is associated with a reduction in antithyroperoxidase antibody levels. Selenium supplementation also in mild Graves orbitopathy is associated with delayed progression of ocular disorders. As a consequence of this observation The European Group on Graves Orbitopathy recommend six months selenium preparates supportive therapy for patients with mild form of Graves orbitopathy.Key words: Graves-Basedows disease - Hashimotos thyroiditis - selenium - supplementation.

The intensity of tyrosine nitration is associated with selenite and selenate toxicity in Brassica juncea L.

Selenium phytotoxicity involves processes like reactive nitrogen species overproduction and nitrosative protein modifications. This study evaluates the toxicity of two selenium forms (selenite and selenate at 0µM, 20µM, 50µM and 100µM concentrations) and its correlation with protein tyrosine nitration in the organs of hydroponically grown Indian mustard (Brassica juncea L.).Selenate treatment resulted in large selenium accumulation in both Brassica organs, while selenite showed slight root-to-shoot translocation resulting in a much lower selenium accumulation in the shoot. Shoot and root growth inhibition and cell viability loss revealed that Brassica tolerates selenate better than selenite. Results also show that relative high amounts of selenium are able to accumulate in Brassica leaves without obvious visible symptoms such as chlorosis or necrosis. The more severe phytotoxicity of selenite was accompanied by more intense protein tyrosine nitration as well as alterations in nitration pattern suggesting a correlation between the degree of Se forms-induced toxicities and nitroproteome size, composition in Brassica organs. These results imply the possibility of considering protein tyrosine nitration as novel biomarker of selenium phytotoxicity, which could help the evaluation of asymptomatic selenium stress of plants.

Crystal structure analysis of selenium-doped hydroxyapatite samples and their thermal stability

The aim of this study is to obtain more information about the fine crystal structure of selenium-doped hydroxyapatite (Se-HA) and investigate the effect of Se doping on the thermal stability of HA. Se-HA samples with different Se/P ratios were synthesized by the chemical precipitation method. The physicochemical properties of the powders were characterized by X-ray fluorescence spectroscopy, X-ray diffraction, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and transmission electron microscopy. The results indicate that selenite and a small amount of carbonate co-incorporate into the well-crystallized samples by substituting for phosphate groups. Rietveld refinement was performed to further analyze the crystal structure and determine the crystal structure model of the Se-HA samples. Se incorporation leads to an increase of the a lattice parameter and a decrease of the c lattice parameter of the crystal lattice. The thermal stability of the Se-HA powders during sintering is also discussed. Doping the HA structure with a small amount of selenium improves the thermal stability of HA. Compared with HA, the Se-HA samples with Se/P ≤ 0.05 doping are more stable after heat treatment without any impurities, which makes these materials promising for bone repair materials.

Supplemented Organic and Inorganic Selenium Affects Milk Performance and Selenium Concentration in Milk and Tissues in the Guanzhong Dairy Goat.

Trace amounts of selenium (Se) are essential for several organisms, and deficiencies therein have adverse effects on growth, development, and reproduction; this is particularly significant in animals raised for milk and livestock production. To study the effect of Se on Guanzhong dairy goats, their diets were supplemented with different sources (inorganic or organic) and Se concentrations (0.2 or 0.4mgSe/kg). A non-Se-fortified basal diet served as a negative control, and a sixth treatment group received both inorganic and organic Se sources (0.2mgSe/kg diet each). Dietary Se supplementation increased milk production, with organic Se being more effective than inorganic Se. Selenium supplementation also increased Se concentration and glutathione peroxidase activity in whole blood, with organic Se more effective than inorganic Se at the same Se concentration. With increasing Se in diets, the Se content in milk increased markedly, reaching a plateau value at day 30 in all groups, and organic Se (0.4mg/kg diet) had the best effect. In addition, dietary Se sources and concentrations markedly affected Se concentrations in different tissues and organs. Thus, organic Se supplementation of a basal diet at 0.4mg/kg is practically applicable for Se-enriched milk and meat production in Guanzhong dairy goats.

Potassium selenotrithionate – the precursor for formation of semiconductive and conductive copper selenide layers on polyamide surface

Semiconducting and electrically conductive layers of copper selenide, CuxSey, on the polyamide 6 (PA) surface were formed using the sorption–diffusion method and the water solutions of potassium selenotrithionate, K2SeS2O6, as the precursor of polymer seleniumization. Selenotrithionate anions containing divalent selenium atoms of low oxidation state, –O3S-Se-SO3–, are sorbed-diffused into PA films if they are treated with selenotrithionate solutions. The concentration of sorbed selenotrithionate increases with an increase of the temperature and concentration of the precursor solution and the duration of PA treatment. CuxSey layers are formed on the surface of a PA film when a chalcogenized polymer is treated with the water solution of copper(II/I) salt: the anions of selenotrithionate react with copper ions. The concentration of copper increases with increasing the concentration and temperature of the precursor solution and the duration of PA initial chalcogenization. The formed layers were characterized for chemical composition, electrical and physical properties. The percentage amounts of selenium and copper in CuxSey layers on PA films with polymer seleniumization time changed as follows: Se from 51.61 to 69.46% and Cu from 48.39 to 30.54%. The most uniform thin layer of CuxSey formed on the polyamide film being seleniumized for 2.5 h was observed by scanning electron microscopy (SEM). The thickness of CuxSey layers depends on polymer seleniumization time and changed in an interval of 0.98–3.2 μm. The X-ray diffraction (XRD) pattern study of CuxSey layers showed that they are polycrystalline in nature; six phases of copper selenides Cu2Se (27-1131), CuSe2 (74-280), CuSe2 (18-453), Cu3Se2 (72-1421) and the phases of berzellianite Cu2-xSe (6-680) and of bellidoite Cu2Se (29-575) were identified. The XPS results confirmed the formation of copper selenides layers on the surface of PA. The regularities established enable the formation of CuySey layers of a desirable composition and conductivity.

In vitro evaluation of probiotic potential of Lactobacillus cultures of human origin capable of selenium bioaccumulation

The probiotic potential of 5 food grade Lactobacillus strains, of human origin namely Lactobacillus fermentum (S23), Lb. fermentum NCDC77 (S8), Lb. fermentum (S25) and Lb. plantarum (S1), capable of selenium bioaccumulation (in previous studies), was investigated. The cultures, S8 and S23 maintained elevated cell numbers under conditions simulating passage through the human gastrointestinal tract, showing ability to survive in the presence of simulated gastric juice at pH 2. These cultures also survived in the presence of simulated intestinal juice with 1% bile salts. The cultures showed variable and strain dependent cell-surface hydrophobicity and auto-aggregation ability. The cultures were assayed for susceptibility to 20 antibiotics and found susceptible to 14 out of 20 antibiotics while showed variable resistance to remaining 6 antibiotics. S8 and S23 cultures showed superior antibacterial activity in comparison to remaining 3 cultures. These findings suggest that Lb. fermentum NCDC77 (S8) and Lb. fermentum (S23) cultures, endowed with the ability to accumulate high amount of selenium, exhibited high resistance against low pH and bile. Moreover, these cultures possessed adherence and auto-aggregation properties with minimum resistance to antibiotics and hence could be exploited for the development of selenium enriched functional food or nutraceutical as a source of dietary selenium.

Evidence for the transfer of a soil‐borne contaminant from plants to ants via an aphid mediator

1. Uptake of environmental contaminants by lower trophic groups can have negative effects on higher trophic groups. This study tested the ability of selenium, an environmental contaminant found in high concentrations throughout the tissues of certain accumulating plants, to be transferred to ants via aphid tissue and honeydew.2. Plants of the selenium accumulator, Raphanus sativus (wild radish), were watered with three different selenium treatments (0, 0.25 or 0.5 µg Se ml−1). Aphids, Myzus persicae, and Argentine ant colonies, Linepithema humile, were added to each caged plant and allowed to interact freely. Ant colonies were supplemented with one of three different food options to encourage the consumption of aphids, aphid honeydew, or aphids and honeydew.3. The accumulation of selenium by each trophic group and a trophic transfer factor (TTF) was calculated. The TTF for plants to aphids was &gt; 1, indicating biomagnification, whereas the TTF for aphids to worker ants was &lt; 1, indicating only biotransfer. Accumulated levels by worker ants did not statistically differ as a result of diet.4. The amounts of selenium acquired by ants as a factor of diet and caste were compared. Plants, aphids and worker ants accumulated selenium in a dose‐dependent manner. Ant queens did not contain detectable amounts of selenium. Honeydew contained comparable amounts of selenium to plant selenium levels.5. Access to toxic compounds via honeydew and insect protein may have negative effects on the range expansion of invasive species, such as the Argentine ant.

Effects of a short-term supranutritional selenium supplementation on redox balance, physiology and insulin-related metabolism in heat-stressed pigs.

Heat stress (HS) disrupts redox balance and insulin-related metabolism. Supplementation with supranutritional amounts of selenium (Se) may enhance glutathione peroxidase (GPX) activity and reduce oxidative stress, but may trigger insulin resistance. Therefore, the aim of this experiment was to investigate the effects of a short-term high Se supplementation on physiology, oxidative stress and insulin-related metabolism in heat-stressed pigs. Twenty-four gilts were fed either a control (0.20ppm Se) or a high Se (1.0ppm Se yeast, HiSe) diet for 2weeks. Pigs were then housed in thermoneutral (20°C) or HS (35°C) conditions for 8days. Blood samples were collected to study blood Se and oxidative stress markers. An oral glucose tolerance test (OGTT) was conducted on day 8 of thermal exposure. The HS conditions increased rectal temperature and respiration rate (both p<.001). The HiSe diet increased blood Se by 12% (p<.05) and ameliorated the increase in rectal temperature (p<.05). Heat stress increased oxidative stress as evidenced by a 48% increase in plasma advanced oxidized protein products (AOPPs; p<.05), which may be associated with the reductions in plasma biological antioxidant potential (BAP) and erythrocyte GPX activity (both p<.05). The HiSe diet did not alleviate the reduction in plasma BAP or increase in AOPPs observed during HS, although it tended to increase erythrocyte GPX activity by 13% (p=.068). Without affecting insulin, HS attenuated lipid mobilization, as evidenced by a lower fasting NEFA concentration (p<.05), which was not mitigated by the HiSe diet. The HiSe diet increased insulin AUC, suggesting it potentiated insulin resistance, although this only occurred under TN conditions (p=.066). In summary, HS induced oxidative stress and attenuated lipid mobilization in pigs. The short-term supranutritional Se supplementation alleviated hyperthermia, but did not protect against oxidative stress in heat-stressed pigs.