• Title, Summary, Keyword: selenite

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Separation of selenite and selenate using magnetite (마그네타이트를 이용한 selenite와 selenate의 분리)

  • Min, Je-Ho;Kim, Seung-Soo;Baik, Min-Hoon;Bae, Kie-Seo
    • Analytical Science and Technology
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    • v.24 no.4
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    • pp.298-303
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    • 2011
  • Selenium is one of the interesting elements in human body, because it's important micro-nutrient for human health as the essential biological tissue in protein. Selenite ($SeO_3^{2-}$) and selenate ($SeO_4^{2-}$) are the dominant dissolved selenium species in natural water, and their toxicity and chemical properties are very different each other. Thus it is necessary to separate the two selenium species for understanding selenium behaviors in natural waters. Some reported methods, using an alumina-filled column and an ion chromatography, to separate the selenite and selenite may be difficult to directly apply to the natural water. Therefore magnetite selectively adsorbs selenite and selenate according to pH of solution, the separation of selenite and selenate using a magnetite-filled column was successfully obtained at weak alkali solutions. Moreover, the influence of dissolved anions in natural water at the selenite sorption onto magnetite was also investigated because they could hinder the sorption of selenite onto magnetite. In other to directly apply to the natural water, reactive sites of magnetite should be considered because dissolved silicate in natural water can hinder the adsorption of selenite onto magnetite.

Absorption and Distribution for Subtoxic Level of Selenite by Vascularly Perfused Small Intestine in Rats (랫드의 소장-혈관의 이중 관류를 통한 저독성 농도의 selenite 흡수와 분포)

  • Park, Yeong-Chul;Yoon, Mi-Sook;Kim, Jong-Bong
    • Journal of Life Science
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    • v.20 no.2
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    • pp.169-175
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    • 2010
  • Intestinally absorptive and distributive aspects of the subtoxic level of selenite in rats were investigated using a double perfusion system. The double-perfusion technique is an in situ, in vitro preparation in which the intestinal lumen and its vasculature are perfused simultaneously. In the previous study, the subtoxic level of sodium selenite was determined to be 1.2 mM through inhibition of 3-0-methyl glucose (3MG) absorption. Thus, the selenite used to identify the intestinally absorptive mechanism of selenite was perfused at a luminal concentration of 1, 10, 50, 100 and $200\;{\mu}M$. Appearance of radiolabeled-Selenium (Se) was identified in three compartments: luminal perfusate, small intestine and vascular perfusate. Dose-response curves for Se in the three compartments indicate that selenite is absorbed by non-mediated passive diffusion. Regarding the distributive aspect, $21.02{\pm}3.92%$ of the total amount of selenite in the lumen was transported into the blood vessels across the small intestine. However, $4.75{\pm}1.75%$ of the total amount of selenite in the lumen is retained by the small intestine. Therefore, a total of $25.67{\pm}4.46%$ of the test dose was taken up from the luminal perfusate.

Synergistic Effect of Ethaselen and Selenite Treatment against A549 Human Non-small Cell Lung Cancer Cells

  • Xu, Wei;Ma, Wei-Wei;Zeng, Hui-Hui
    • Asian Pacific Journal of Cancer Prevention
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    • v.15 no.17
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    • pp.7129-7135
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    • 2014
  • Background: In this study, we aimed to evaluate the growth inhibitory effect of the combination of ethaselen (BBSKE) and low fixed dose of selenite against A549 human non-small cell lung cancer cells in vitro. Materials and Methods: Growth inhibitory effects against A549 cells were determined by SRB assay. Combination index (CI) values were calculated based on Chou-Talalay median-effect analyses. Dose reduction index (DRI) values were applied to calculate dose reduction of selenite. Contents of free thiols and GSH were determined by DTNB assay and intracellular ROS levels by DCFH-DA fluorescence labeling. Results: Compared with BBSKE or selenite single treatment, the combined application of ethaselen and a low fixed dose of selenite shortened the onset time of sodium selenite, reduced $IC_{50}$ values, and increased the maximum inhibition rates, suggesting a possible molecular mechanism of the synergism. Obvious synergistic effects were observed after different times of combination treatment, especially after 24 h. Compared with selenite single treatment, dosage of selenite could be remarkably reduced in combination therapy to gain the same inhibitory effect on cell proliferation. Compared with BBSKE single treatment, the content of free thiols and GSH were significantly reduced and ROS levels greatly elevated in the combination group. For the combination treatment, cell viability increased as greater concentrations of GSH were added. Conclusions: All these results indicate that the combination treatment of BBSKE and selenite showed synergism to inhibit A549 cell proliferation in vitro, and also reduced the selenite dosage to mitigate its toxicity which is very meaningful for combination chemotherapy of lung cancer. The synergism was probably caused by the accelerated exhaustion of intracellular reductive substances, such as free thiols and GSH, which ultimately leads to enhanced oxidative stress and apoptosis.

Selenite Stress Elicits Physiological Adaptations in Bacillus sp. (Strain JS-2)

  • Dhanjal, Soniya;Cameotra, Swaranjit Singh
    • Journal of Microbiology and Biotechnology
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    • v.21 no.11
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    • pp.1184-1192
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    • 2011
  • A bacterial isolate (strain JS-2) characterized as Bacillus sp. was challenged with high concentrations of toxic selenite ions. The microbe was found to transform the toxic, soluble, colorless selenite (${SeO_3}^{2-}$) oxyions to nontoxic, insoluble, red elemental selenium ($Se^0$). This process of biotransformation was accompanied by cytoplasmic and surface accumulation of electron dense selenium ($Se^0$) granules, as revealed in electron micrographs. The cells grown in the presence of selenite oxyions secreted large quantities of extracellular polymeric substances (EPS). There were quantitative and qualitative differences in the cell wall fatty acids of the culture grown in the presence of selenite ions. The relative percentage of total saturated fatty acid and cyclic fatty acid increased significantly, whereas the amount of total unsaturated fatty acids decreased when the cells were exposed to selenite stress. All these physiological adaptive responses evidently indicate a potentially important role of cell wall fatty acids and extracellular polymeric substances in determining bacterial adaptation towards selenite-induced toxicity, which thereby explains the remarkable competitiveness and ability of this microbe to survive the environmental stress.

Influence of sodium selenite on oxygen free radical in mercuric chloride induced renal failure (Mercuric chloride 유발 신부전에서 산소유리기에 미치는 Sodium selenite의 영향)

  • Kim, Hyoung-Chun;Jhoo, Wang-Kee;Huh, In-Hoi
    • YAKHAK HOEJI
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    • v.32 no.4
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    • pp.287-293
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    • 1988
  • Oxygen free radical have recently been found to mediate cell injury after ischemia in the kidney. The purpose of our study was to determine whether selenium had an effect on damge mediated by oxygen free radical in inorganic mercury induced renal failure, toxic model of renal failure. Toxic renal failure model was produced by subcutaneous injection of mercuric chloride (4mg/kg) once a day for 7 consecutive days. In additionally, coadministration of sodium selenite (1mg/kg) was performed by the same condition. As a consequence of this study, we were able to detect partially unequivocal role of selenium as below dipicted. The combination of sodium selenite showed that markedly inhibited production of superoxide radical in mercuric chloride alone. On the other hand, combined sodium selenite was unable to enhance against significantly lowered superoxide dismutase activity after mercuric chloride insult. However, simultaneous administration of sodium selenite was inclined to induce mitochondrial superoxide dismutase and catalase.

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Effects of Sodium Selenite on Merthiolate-induced Mercury Distribution in Rat. (흰쥐에서 Merthiolate로 인한 수은의 체내 분포에 미치는 Sodium Selenite의 영향)

  • 손동헌;김영춘;허무영;주왕기;허인회
    • YAKHAK HOEJI
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    • v.29 no.4
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    • pp.223-226
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    • 1985
  • 0.1%-Merthiolate solutions were applied to rats with or without sodium selenite. Rat organs were excised under ether anesthesia. Mercury contents in rat tissues were determined by quartz tube combustion gold amalgamation method. Mercury contents were accumulated at about 3-fold in the brain, 143-fold in the kidney, 62-fold in the blood cell, 22-fold in the liver than those of untreated rats respectively, on the 1st day after application of mert iolate for 7 days. On the other hand, the addition of sodium selenite caused a shift in the tissue mercury distribution. Our study showed that simultaneous administration of sodium selenite increased the accumulation of mercury in the brain, but became to decrease it after 9 days, while decreased it in the kidney, but grew to increase it, respectively.

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ESTIMATION OF THE BEHAVIORS OF SELENIUM IN THE NEAR FIELD OF REPOSITORY

  • Kim, Seung-Soo;Min, Jae-Ho;Baik, Min-Hoon;Kim, Gye-Nam;Choi, Jong-Won
    • Nuclear Engineering and Technology
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    • v.44 no.8
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    • pp.945-952
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    • 2012
  • The sorption of selenium ions onto iron and iron compounds as a disposal container material and its corrosion products, and onto bentonite as a buffer material, was studied to understand the behaviors of selenium in a waste repository. Selenite was sorbed onto commercial magnetite very well in solutions at around pH 9, but silicate hindered their sorption onto both magnetite and ferrite. Unlike commercial magnetite and ferrite, flesh synthesized magnetite, green rust and iron greatly decreased selenium concentration even in a silicate solution. These results might be due to the formation of precipitates, or the sorption of selenide or selenite onto an iron surface at below Eh= -0.2 V. Red-colored Se(cr) was observed on the surface of a reaction bottle containing iron powder added into a selenite solution. Silicate influences on the sorption onto magnetite and iron for selenide are the same as those for selenite. Even though bentonite adsorbed a slight amount of selenite, the sorption cannot be ignored in the waste repository since a very large quantity of bentonite is used.

Effect of Sodium Selenite and Zinc-L-selenomethionine on Performance and Selenium Concentrations in Eggs of Laying Hens

  • Chantiratikul, Anut;Chinrasri, Orawan;Chantiratikul, Piyanete
    • Asian-Australasian Journal of Animal Sciences
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    • v.21 no.7
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    • pp.1048-1052
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    • 2008
  • The objective of this study was to determine the effect of sodium selenite and zinc-L-selenomethionine on performance and egg Se concentration in laying hens. Two hundred and twenty-four CP Browns aged 71 weeks were divided according to a $2{\times}3$ factorial in a completely randomized design. One more group without additional Se supplementation was used as a negative control. Each treatment consisted of four replicates and each replicate contained eight laying hens. The dietary treatments were T1: basal diet; T2, T3 and T4: basal diets plus 0.3, 1.0 and 3.0 mg Se from sodium selenite/kg, respectively; T5, T6 and T7: basal diets plus 0.3, 1.0 and 3.0 mg Se from zinc-L-selenomethionine/kg, respectively. The findings revealed that feed conversion rate/kg eggs, egg production, egg weight, Haugh units and eggshell thickness were not affected by source and level of Se (p>0.05). Increasing level of dietary Se significantly increased (p<0.05 the Se content of eggs. Zinc-L-selenomethionine markedly increased p<0.05 egg Se concentration as compared with sodium selenite. The results indicated that Se source did not influence performance of laying hens. However, zinc-L-selenomethionine increased p<0.05 egg Se concentration more than sodium selenite.

Selenite Reduction to Elemental Selenium by Citrobacter Strain SE4-1 Isolated from a Stream Sediment (하천 퇴적토에서 분리한 Citrobacter strain SE4-1에 의한 아셀렌산염의 원소상 셀레늄으로의 환원)

  • Lee, Ji-Hoon;Cho, Ahyeon;Lee, Hyeri
    • Korean Journal of Environmental Agriculture
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    • v.37 no.2
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    • pp.146-149
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    • 2018
  • BACKGROUND: Selenium is an essential element for all life forms but can be toxic above certain narrow levels. Prevalent forms of selenium in oxic environment are selenium oxyanions such as selenite and selenate, which may be contaminants in soils and water bodies. Bacterial reduction of more mobile selenium species (selenite or selenate) to less mobile elemental selenium may suggest a benign solution for alleviating toxicity and bioavailability of the selenium species. METHODS AND RESULTS: A facultative anaerobic bacterium, Citrobacter strain SE4-1 was isolated from the contaminated stream sediments and found to effectively reduce selenite to elemental selenium. Aqueous phase of selenite was analyzed by inductively couple plasma spectroscopy and the precipitated sphere-shaped elemental selenium was observed by transmission electron microscopy. CONCLUSION: The bacterial strain SE4-1 isolated in this study suggests a potential role in biogeochemical cycle of selenium by the selenite reduction in the stream environment, and potentials for biotechnological applications to reduceselenium concentrations in selenium-contaminated systems such as wastewater, soil, and groundwater.

A Comparison of three Enrichment Media for Isolating Salmonella (Salmonella균(菌) 분리용(分離用) 증균배지(增菌培地)의 비교실험(比較實驗))

  • Kim, Yong-Ja;Lee, Seung-Yun;Park, Kee-Deuk;Min, Chang-Hong
    • The Journal of the Korean Society for Microbiology
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    • v.11 no.1
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    • pp.33-48
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    • 1976
  • The practical significance of using a selective enrichment procedure for detecion and enumeration of salmonella is well recognized. There are still various selective enrichment media has been communly used. Early years selenite broth was recomnended as an enrichment media for the isolating of salmonella. Hajna introduced a modified tetrathionate broth and demonstrated the greater efficiency to compare with the previous enrichment media. Raj also described that the new medium called dulcitol selenite enrichment and has been found to be very satisfactory, especially general implication in food poisoning. Authors tried to compare these 3 enrichment media for isolating salmonella. 1. When salmonella strains were inoculated $1{\sim}10^6$ cells per tube to these 3 enrichment media, mostly similar results were obtained between selenite broth and DS broth. In these 2 enrichment broth were showed $10^7/ml-10^8/ml$ cells of all tested salmonella strains. But in the case of TT broth it was found that the growth was $10^3/ml{\sim}10^4/ml$ cells for tested strain. 2. When E. coli, Proteus, Citrobacter were inoculate $10{\sim}10^6$ cells per tube to these 3 enrichment media. It was suggested that DS broth was showed more inhibitory action than that of selenite broth. TT broth showed high inhibition to these 3 organisms tested. 3. It was generally known that the incubation time is influenced to the frequency of salmonella detection. For this tendency, DS broth and selenite broth were showed similar results within 24 hrs to 48hrs incubation to the test. But DS broth showed more inhibitory action to E. coli and Proteus than that of selenite broth. 4. When $1{\sim}10$ cells were inoculated(per tube) to these 3 enrichment media, DS broth was found to be more sensitive than that of selenite broth.

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