scholarly journals Duckweed (Lemna minor L.) Successfully Accumulates Selenium from Selenium-Impacted Water

2021 ◽  
Vol 13 (23) ◽  
pp. 13423
Author(s):  
Aleksandra Golob ◽  
Katarina Vogel-Mikuš ◽  
Nina Brudar ◽  
Mateja Germ
Keyword(s):  
Photosynthetic Pigments ◽  
Sodium Selenite ◽  
Lemna Minor ◽  
Morphological Characteristics ◽  
Stress Conditions ◽  
Sodium Selenate ◽  
Potential Use

The absorption of selenium (Se) from water by Lemna minor L. and the influence of different concentrations and forms of Se on its biochemical and morphological characteristics were studied. Plants were exposed to various concentrations of Se: 1 mg Se L−1, 2 mg Se L−1 and 5 mg Se L−1 in sodium selenite and sodium selenate solutions and in a combination of selenite (2 mg Se L−1) and selenate (2 mg Se L−1). When the Se was added in the form of selenate, plants accumulated higher amounts of Se compared to plants exposed to selenite. Comparisons of the combined addition of selenite and selenate (2 + 2 mg Se L−1) with their individual applications (2 and 5 mg Se L−1) showed that for the combination, the L. minor fronds accumulated more Se than in selenite alone. Plants exposed to any of the concentrations of sodium selenate or sodium selenite, or the combination of selenite and selenate, showed inferior physiological performances, and lower concentrations of photosynthetic pigments, compared to control plants. Consequently, growth was also suppressed under the stress conditions caused by higher concentrations of Se in any form. The efficient absorption of Se from the water by L. minor indicates the potential use of this species in phytoremediation processes for waters polluted with Se.

scholarly journals Freshwater Bacteria Can Methylate Selenium through the Thiopurine Methyltransferase Pathway

2003 ◽  
Vol 69 (7) ◽  
pp. 3784-3790 ◽  
Author(s):  
Lionel Ranjard ◽  
Sylvie Nazaret ◽  
Benoit Cournoyer
Keyword(s):  
Pseudomonas Syringae ◽  
Sodium Selenite ◽  
Blot Hybridization ◽  
Sodium Selenate ◽  
Thiopurine Methyltransferase ◽  
Freshwater Environment ◽  
Reading Frame ◽  
Dna Library ◽  
Freshwater Bacteria ◽  
Genomic Dna Library

ABSTRACT Involvement of the bacterial thiopurine methyltransferase (bTPMT) in natural selenium methylation by freshwater was investigated. A freshwater environment that had no known selenium contamination but exhibited reproducible emission of dimethyl selenide (DMSe) or dimethyl diselenide (DMDSe) when it was supplemented with an organic form of selenium [(methyl)selenocysteine] or an inorganic form of selenium (sodium selenite) was used. The distribution of the bTPMT gene (tpm) in the microflora was studied. Freshwater bacteria growing on 10 μM sodium selenite and 10 μM sodium selenate were isolated, and 4.5 and 10% of the strains, respectively, were shown by colony blot hybridization to hybridize with a Pseudomonas syringae tpm DNA probe. Ribotyping showed that these strains are closely related. The complete rrs sequence of one of the strains, designated Hsa.28, was obtained and analyzed. Its closest phyletic neighbor was found to be the Pseudomonas anguilliseptica rrs sequence. The Hsa.28 strain grown with sodium selenite or (methyl)selenocysteine produced significant amounts of DMSe and DMDSe. The Hsa.28 tpm gene was isolated by genomic DNA library screening and sequencing. BLASTP comparisons of the deduced Hsa.28 bTPMT sequence with P. syringae, Pseudomonas aeruginosa, Vibrio cholerae, rat, and human thiopurine methyltransferase sequences revealed that the levels of similarity were 52 to 71%. PCR-generated Escherichia coli subclones containing the Hsa.28 tpm open reading frame were constructed. E. coli cells harboring the constructs and grown with sodium selenite or (methyl)selenocysteine produced significant levels of DMSe and DMDSe, confirming that the gene plays a role in selenium methylation. The effect of strain Hsa.28 population levels on freshwater DMSe and DMDSe emission was investigated. An increase in the size of the Hsa.28 population was found to enhance significantly the emission of methyl selenides by freshwater samples supplemented with sodium selenite or (methyl)selenocysteine. These data suggest that bTPMT can play a role in natural freshwater selenium methylation processes.

scholarly journals Effect of Rice Grain (Oryza sativa L.) Enrichment with Selenium on Foliar Leaf Gas Exchanges and Accumulation of Nutrients

Plants ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 288
Author(s):  
Ana Coelho Marques ◽  
Fernando C. Lidon ◽  
Ana Rita F. Coelho ◽  
Cláudia Campos Pessoa ◽  
Inês Carmo Luís ◽  
...  
Keyword(s):  
Sodium Selenite ◽  
Oryza Sativa L ◽  
Fold Increase ◽  
Physiological Data ◽  
Sodium Selenate ◽  
Rice Grain ◽  
Rice Cultivars ◽  
Gas Exchanges ◽  
Toxicity Threshold ◽  
Leaf Gas Exchanges

An agronomic itinerary for Se biofortification of two rice cultivars (Ariete and Ceres) through foliar fertilization with sodium selenate and sodium selenite with different concentrations (25, 50, 75 and 100 g Se.ha−1), was implemented in experimental fields. The selenium toxicity threshold was not exceeded, as shown by the eco-physiological data obtained through leaf gas exchanges. The highest Se enrichment in paddy grains was obtained with selenite for both cultivars, especially at the highest doses, i.e., 75 and 100 g Se.ha−1, with approximately a 5.0-fold increase compared with control values. In paddy grains, Zn was the most affected element by the treatments with Se with decreases up to 54%. When comparing the losses between rough and polished grains regardless of the cultivars, Se species and concentrations, it was observed that only Cu, Mg and Zn exhibited losses <50%. The remaining elements generally had losses >70%. The loss of Se is more pronounced in Ceres cultivar than in Ariete but rarely exceeds 50%. The analysis by µ-EDXRF showed that, in Ariete cultivar, Se is mostly homogeneously distributed in the grain regardless of any treatments, while in Ceres cultivar, the Se distribution seems to favor accumulation in the periphery, perhaps in the bran.

scholarly journals Impact of selenite and selenate on differentially expressed genes in rat liver examined by microarray analysis

2010 ◽  
Vol 30 (5) ◽  
pp. 293-306 ◽  
Author(s):  
Astrid C. Bosse ◽  
Josef Pallauf ◽  
Bettina Hommel ◽  
Mariana Sturm ◽  
Susanne Fischer ◽  
...  
Keyword(s):  
Rat Liver ◽  
Sodium Selenite ◽  
Metabolic Regulation ◽  
Biological Effects ◽  
Male Rats ◽  
Sodium Selenate ◽  
Deficient Diet ◽  
Selenium Compounds ◽  
Genes Encoding ◽  
Se Deficiency

Sodium selenite and sodium selenate are approved inorganic Se (selenium) compounds in human and animal nutrition serving as precursors for selenoprotein synthesis. In recent years, numerous additional biological effects over and above their functions in selenoproteins have been reported. For greater insight into these effects, our present study examined the influence of selenite and selenate on the differential expression of genes encoding non-selenoproteins in the rat liver using microarray technology. Five groups of nine growing male rats were fed with an Se-deficient diet or diets supplemented with 0.20 or 1.0 mg of Se/kg as sodium selenite or sodium selenate for 8 weeks. Genes that were more than 2.5-fold up- or down-regulated by selenite or selenate compared with Se deficiency were selected. GPx1 (glutathione peroxidase 1) was up-regulated 5.5-fold by both Se compounds, whereas GPx4 was up-regulated by only 1.4-fold. Selenite and selenate down-regulated three phase II enzymes. Despite the regulation of many other genes in an analogous manner, frequently only selenate changed the expression of these genes significantly. In particular, genes involved in the regulation of the cell cycle, apoptosis, intermediary metabolism and those involved in Se-deficiency disorders were more strongly influenced by selenate. The comparison of selenite- and selenate-regulated genes revealed that selenate may have additional functions in the protection of the liver, and that it may be more active in metabolic regulation. In our opinion the more pronounced influence of selenate compared with selenite on differential gene expression results from fundamental differences in the metabolism of these two Se compounds.

scholarly journals Relative Stability of Selenites and Selenates in Feed Premixes as a Function of Water Activity

2007 ◽  
Vol 90 (2) ◽  
pp. 349-353 ◽  
Author(s):  
Sylvan Eisenberg
Keyword(s):  
Ascorbic Acid ◽  
Moisture Content ◽  
Water Activity ◽  
Filter Paper ◽  
Sodium Selenite ◽  
High Water ◽  
Sodium Selenate ◽  
Elemental Selenium ◽  
The Subject ◽  
Vapor Analysis

Abstract Sodium selenite is more hygroscopic than sodium selenate. It is, therefore, more likely to dissolve when dispersed in feeds of relatively high water activity. When dissolved, it may form selenious acid and disperse as a vapor. This is easily demonstrated by mounting a filter paper wetted with a reagent such as ascorbic acid over the subject feed, but not in contact with it. The paper turns brown as elemental selenium is formed from reduction of the vapor. Analysis of the paper ensures that the brown is indeed selenium. Though premixes are generally low enough in moisture content to ensure stability of the selenites, this is not true of many feeds. The water activities of a number of feeds, feed premixes, and feed ingredients have been determined instrumentally and compared to those of saturated solutions of sodium selenite and sodium selenate. There is no question that the selenite often dissolves with the potential to react and, in so doing, loses its nutritional function.

scholarly journals Colorimetric Determination of Selenium in Mineral Premixes

1997 ◽  
Vol 80 (4) ◽  
pp. 709-716
Author(s):  
Jeffrey A Hurlbut ◽  
Roger G Burkepile ◽  
Carolyn A Geisler ◽  
Philip James Kliak ◽  
Nathan G Rummel
Keyword(s):  
Calcium Carbonate ◽  
Sodium Selenite ◽  
Ethylenediaminetetraacetic Acid ◽  
Base Material ◽  
Magnesium Carbonate ◽  
Sodium Selenate ◽  
Colorimetric Determination ◽  
Sample Type ◽  
Coefficients Of Variation

Abstract A method is described for determination of sodium selenite or sodium selenate in mineral-based premixes. It is based on the formation of intense-yellow piazselenol by Se(IV) and 3,3’-diaminobenzid- ine. Mineral premixes typically contain calcium carbonate as a base material and magnesium carbonate, silicon dioxide, and iron(lll) oxide as minor components or additives. In this method, the premix is digested briefly in nitric acid, diluted with water, and filtered to remove any iron(lll) oxide. Ethylenediaminetetraacetic acid and HCI are added to the filtrate, which is heated to near boiling for 1 h to convert any selenate to selenite. After heating, the solution is buffered between pH 2 and 3 with NaOH and formic acid and treated with NH2OH and EDTA; any Se present forms a complex with 3,3’- diaminobenzidine at 60°C. The solution is made basic with NH4OH, and the piazselenol is extracted into toluene. The absorbance of the complex in dried toluene is measured at 420 nm. The method was validated independently by 2 laboratories. Samples analyzed included calcium carbonate fortified with 100, 200, and 300 μg Se in the form of sodium selenite or sodium selenate, a calcium carbonate premix containing sodium selenite, a calcium carbonate premix containing sodium selenate, and a commercial premix; 5 replicates of each sample type were analyzed by each laboratory. Average recoveries ranged from 89 to 109% with coefficients of variation from 1.2 to 13.6%.

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