Subcellular distribution of selenium during uptake and its influence on mitochondrial oxidations in germinating Vigna radiata L.
TL;DR: In seedlings grown with supplemented Se, enhanced respiratory control ratio and succinate dehydrogenase activity were observed in the mitochondria of tissues, indicative of a role for Se in mitochondrial membrane functions.
Abstract: The metabolic significance of Se in plants is not well documented, though the presence of many selenoenzymes in bacteria and the essentiality of Se in higher animals is established. Since germination is an active process in plant growth and metabolism, the effect of Se was investigated in germinatingVigna radiata L, a nonaccumulating Sedeficient legume. Growth and protein were enhanced in seedlings supplemented with selenium (Se) as sodium selenite in the medium up to 1 μg/mL. The pattern of uptake of75Se in the differentiating tissues and the subcellular distribution were investigated. The percentage of incorporation of75Se was greater in the mitochondria at the lowest level (0.5 μg/mL) of Se supplementation compared to higher levels of Se exposure. Proteins precipitated from the postmitochondrial supernatant fractions, when separated by means of polyacrylamide gel electrophoresis (PAGE), indicated a major selenoprotein in the seedlings germinated at 2.0 μg/mL Se. In seedlings grown with supplemented Se, enhanced respiratory control ratio and succinate dehydrogenase activity were observed in the mitochondria of tissues, indicative of a role for Se in mitochondrial membrane functions.
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TL;DR: Although there was no change in total biomass, Se treatment was associated with a 43% increase in seed production and the Se-treated Brassica plants had higher total respiratory activity in leaves and flowers, which may have contributed to higher seed production.
Abstract: Selenium (Se) is essential for humans and animals but is not considered to be essential for higher plants. Although researchers have found increases in vegetative growth due to fertiliser Se, there has been no definitive evidence to date of increased reproductive capacity, in terms of seed production and seed viability. The aim of this study was to evaluate seed production and growth responses to a low dose of Se (as sodium selenite, added to solution culture) compared to very low-Se controls in fast-cycling Brassica rapa L. Although there was no change in total biomass, Se treatment was associated with a 43% increase in seed production. The Se-treated Brassica plants had higher total respiratory activity in leaves and flowers, which may have contributed to higher seed production. This study provides additional evidence for a beneficial role for Se in higher plants.
181 citations
Cites background from "Subcellular distribution of seleniu..."
...When a major selenoprotein was discovered in mung bean (Vigna radiata L.) seedlings supplemented with 2 mg L−1 of selenite, a role for Se in mitochondrial membrane functions was indicated (Easwari and Lalitha 1994)....
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TL;DR: Experimental effects of untreated (Raw) distillery effluent, discharged from a distillery unit (based on fermentation of alcohol from sugarcane molasses), and the post-treatment effluent from the outlet of conventional anaerobic treatment plant (Treated effluent) of thedistillery unit were studied in mung bean.
118 citations
TL;DR: The Selenium-Conta in ing Proteins in Mammal Tissues and other Selenoproteins in Various Forms of Life and Selenium and Sulfur: Compar ison of Relevant Properties is compared.
Abstract: 1 In t roduct ion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 2 Milestones in Selenoprotein Research . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 3 General Aspects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 3.1 Selenium and Sulfur: Compar ison of Relevant Properties . . . . . 5 3.2 Format ion of Selenocysteine-Containing Proteins . . . . . . . . . . . . 6 4 Selenium-Conta in ing Proteins in Various Forms of Life . . . . . . . . . . . . 7 4.1 Selenium-Conta in ing Proteins in Plants . . . . . . . . . . . . . . . . . . . . . 7 4.2 Selenium-Conta in ing Proteins in Yeasts . . . . . . . . . . . . . . . . . . . . . 9 4.3 Selenium-Conta ining Proteins in Bacteria and Archaea . . . . . . . 10 4.3.1 Formate Dehydrogenases . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 4.3.2 Reductases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 4.3.3 Hydrogenases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 4.3.4 Other Selenoproteins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 4.3.5 Selenium-Dependent Enzymes . . . . . . . . . . . . . . . . . . . . . . 15 5 Selenium-Conta in ing Proteins in Mammals . . . . . . . . . . . . . . . . . . . . . . 16 5.1 General Points . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 5.1.1 Selenium and Selenium-Conta in ing Proteins in Mammal ian Tissues . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 5.1.2 Chemical Forms of Selenium in the Mammal ian Selenium-Conta ining Proteins . . . . . . . . . . . . 18 5.2 Selenoenzymes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 5.2.1 Glutathione Peroxidases . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 5.2.2 Iodothyronine Deiodinases . . . . . . . . . . . . . . . . . . . . . . . . . 24 5.2.3 Thioredoxin Reductases . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 5.2.4 Selenophosphate Synthetase 2 . . . . . . . . . . . . . . . . . . . . . . . 28 5.3 Selenoproteins with Funct ions still Unknow n . . . . . . . . . . . . . . . . 28 5.3.1 Selenoprotein P . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 5.3.2 Selenoprotein W . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 5.3.3 15kDase lenopro te in . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
70 citations
31 citations
TL;DR: The results including the differential response of GR activity to Se or mimosine supplementation are reflective of an effective reductive environment in Se groups and increased turnover of GSH in the presence of Mimosine.
Abstract: Actaptive alterations in glutathione (GSH) metabolism were studied during oxidative stress induced by selenium (Se) deficiency in germinating seedlings ofTrigonella foenum- graecum grown for 72 h and the response to supplementation individually of Se or mimosine was explored. Growth enhancement with improved mitochondrial efficiency was elicited by supplementation of Se at 0.5-0.75 ppm or mimosine at 0.1-0.2 mM. Total thiol and protein levels of mitochondrial and soluble fractions, in general, did not vary significantly with supplementation of either Se or mimosine except that the mitochondrial protein levels in mimosine groups (0.1-0.2 mM) decreased by 20–30%. Mitochondrial glutathione peroxidase (GSH-Px) increased by twofold in activity toward H2O2, cumene hydroperoxide (CHP), and t-butyl hydroperoxide (tBHP) in Se groups, and by 50–60% increase toward H2O2 and CHP but by a twofold enhancement in enzyme activity with tBHP in mimosine groups. Soluble GSH-Px activity increased by 30–40% only in mimosine groups and remained unaltered in Se groups. Glutathione S-transferase activity (GST) in the soluble fraction of both Se and mimosine groups increased dramatically by fivefold to sixfold. Distinct differences were noted in the response of the stressed seedlings toward exposure to Se or mimosine and included a decline in glutathione reductase (GR) activity by 50–60% in both mitochondria and soluble fractions of Se groups and an increase in GR activity of the mitochondria by twofold and of the soluble enzyme activity by 30% in the mimosine groups. Mimosine exposure resulted in a dose-dependent decrease in the γ-glutamyl transpeptidase levels, but, in contrast, a significant enhancement by 50% was noted in the Se group at 0.75 ppm. The results including the differential response of GR activity to Se or mimosine supplementation are reflective of an effective reductive environment in Se groups and increased turnover of GSH in the presence of mimosine.
23 citations
Cites background from "Subcellular distribution of seleniu..."
...Earlier studies from our laboratory on the legume Vigna radiata, demonstrated the presence of GSH-Px and GST and the relevance of Se in hydroperoxide metabolism (16)....
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References
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Journal Article•
TL;DR: Procedures are described for measuring protein in solution or after precipitation with acids or other agents, and for the determination of as little as 0.2 gamma of protein.
289,852 citations
01 Jan 1966
26,383 citations
"Subcellular distribution of seleniu..." refers methods in this paper
...Estimations were also done using PMS as an electrontransfer mediator along with DCPIP (36) and by the method of Bonner (37) using ferricyanide....
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TL;DR: A water-soluble (at pH 8) aromatic disulfide [5,5′-dithiobis(2-nitrobenzoic acid] has been synthesized and shown to be useful for determination of sulfhydryl groups.
23,232 citations
TL;DR: When hemolyzates from erythrocytes of selenium-deficient rats were incubated in vitro in the presence of ascorbate or H2O2, added glutathione failed to protect the hemoglobin from oxidative damage.
Abstract: When hemolyzates from erythrocytes of selenium-deficient rats were incubated in vitro in the presence of ascorbate or H(2)O(2), added glutathione failed to protect the hemoglobin from oxidative damage. This occurred because the erythrocytes were practically devoid of glutathione-peroxidase activity. Extensively purified preparations of glutathione peroxidase contained a large part of the (75)Se of erythrocytes labeled in vivo. Many of the nutritional effects of selenium can be explained by its role in glutathione peroxidase.
6,893 citations
1,676 citations