Oxidative stress during selenium deficiency in seedlings oftrigonella foenum-graecum and mitigation by mimosine
TL;DR: It is demonstrated for the first time that mimosine, a naturally occuring toxic amino acid, could be a beneficial growth factor in concentrations between 0.1 and 0.2 mM.
Abstract: Oxidative stress during selenium (Se) deficiency in the seedlings ofTrigonella foenum-graecum grown for 72 h was investigated and the response to supplemented levels of Se (0.5-1 ppm) and mimosine (0.05-1 mM) was evaluated. Beneficial effects of Se was maximal at 0.75 ppm. Mimosine, a toxic amino acid, was also found to be beneficial to the growth of the seedlings exposed up to 0.2 mM. When compared to the stressed seedlings, mitochondrial oxygen uptake from seedlings of Se (0.75 ppm) group and mimosine (0.2 mM) group exhibited threefold enhancement in state 3 respiration rate and a controlled state 4 rate, with respiratory control ratios of 5–8. Upon supplementation at the optimal levels, Superoxide dismutase (SOD) activities were enhanced fourfold with Se and eightfold with mimosine in the mitochondria. The soluble activity in mimosine groups increased twofold, but only by 75% in Se groups. Peroxidase activity registered a significant increase by threefold in mitochondria and fourfold in soluble fraction in both Se and mimosine groups. Exposure to Se or mimosine exhibited a differential response in the mitochondrial catalase and ascorbate peroxidase (Asc-Px) activities. In the Se groups, both catalase and Asc-Px in mitochondria decreased by 50–60%, which was contrasted by 60% increase in Asc-Px activity and 40% in catalase activity in mimosine groups. Supplementation with either Se or mimosine evoked similar responses of increases with respect to soluble catalase by twofold to threefold and Asc-Px by 90%. The results of the present study reveal (1) the Prevalence of oxidative stress inT. foenum-graecum during Se deficiency, (2) enhanced mitochondrial functional efficiency mediated by Se and mimosine independently, and (3) an antitoxidative role for mimosine during Se deficiency. The study demonstrates for the first time that mimosine, a naturally occuring toxic amino acid, could be a beneficial growth factor in concentrations between 0.1 and 0.2 mM.
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TL;DR: This review is to assess the mode of action and role of antioxidants in protecting plants from stress caused by the presence of heavy metals in the environment.
Abstract: The contamination of soils and water with metals has created a major environmental problem, leading to considerable losses in plant productivity and hazardous health effects. Exposure to toxic metals can intensify the production of reactive oxygen species (ROS), which are continuously produced in both unstressed and stressed plants cells. Some of the ROS species are highly toxic and must be detoxified by cellular stress responses, if the plant is to survive and grow. The aim of this review is to assess the mode of action and role of antioxidants in protecting plants from stress caused by the presence of heavy metals in the environment.
1,065 citations
TL;DR: The results suggest that Se is an antioxidant or it activates protective mechanisms, which can alleviate oxidative stress in the chloroplasts, and improve the recovery of chlorophyll content following light stress.
209 citations
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 "Oxidative stress during selenium de..."
...Mitochondrial GSH-Px was found to increase three-fold when fenugreek (Trigonella foenum-graecum L.) plants were supplemented with Se (Sreekala et al. 1999)....
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TL;DR: This review attempts to appraise the literature related to non-protein amino acids, both in terms of their metabolism, plant–soil interactions and at the level of the ecosystem, where they are seen as significant drivers of structure and function.
Abstract: Non-protein amino acids are a significant store of organic nitrogen in many ecosystems, but there is a lack of knowledge relating to them. Research has indicated that they play important roles as metabolites, as allelopthic chemicals, in nutrient acquisition, in signalling and in stress response. They are also thought to be responsible for significant medical issues in both invertebrate and vertebrate animals. This review attempts to appraise the literature related to non-protein amino acids, both in terms of their metabolism, plant–soil interactions and at the level of the ecosystem, where they are seen as significant drivers of structure and function. Finally, important areas for future research are discussed.
120 citations
Cites background from "Oxidative stress during selenium de..."
...…in Fe nutrition, allelochemical, growth factor Crounse et al. 1962; Hylin and Lichton 1965; Jones 1979; Ebuenga et al. 1979; Serrano et al. 1983; Sreekala et al. 1999; Santosh et al. 1999; Borthakur et al. 2003; Xuan et al. 2006; Andrade et al. 2009 3-aminopropionic acid -alanine Precursor,…...
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TL;DR: An extra isoenzyme of glutathione reductase (GR) was induced in the presence of selenite, which confirmed the previous results obtained with Cd and Ni indicating that this GR isoenzymes may have the potential to be a marker for oxidative stress in coffee.
Abstract: Selenium (Se) is an essential element for humans and animals that is required for key antioxidant reactions, but can be toxic at high concentrations. We have investigated the effect of Se in the form of selenite on coffee cell suspension cultures over a 12-day period. The antioxidant defence systems were induced in coffee cells grown in the presence of 0.05 and 0.5 mm sodium selenite (Na2SeO3). Lipid peroxidation and alterations in antioxidant enzymes were the main responses observed, including a severe reduction in ascorbate peroxidase activity, even at 0.05 mm sodium selenite. Ten superoxide dismutase (SOD) isoenzymes were detected and the two major Mn-SOD isoenzymes (bands V and VI) responded more to 0.05 mm selenite. SOD band V exhibited a general decrease in activity after 12 h of treatment with 0.05 mm selenite, whereas band VI exhibited the opposite behavior and increased in activity. An extra isoenzyme of glutathione reductase (GR) was induced in the presence of selenite, which confirmed our previous results obtained with Cd and Ni indicating that this GR isoenzyme may have the potential to be a marker for oxidative stress in coffee.
99 citations
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TL;DR: The purification and biochemical characterization of a selenocysteine methyltransferase from cultured Astragalus bisculatus cells is described, and it is proposed that this enzyme plays a crucial role in conferring selenium tolerance.
Abstract: Selected members of the genus Astragulus (Fabaceae) are known for their ability to accumulate high levels of selenium, mainly in the form of Se-methyl-selenocysteine. With the aid of cell cultures we have investigated the molecular basis for selenium tolerance of these plants. It is shown that cultured cells from a selenium-accumulating Astragalus species synthesize Se-methyl-selenocysteine in contrast to those of a non-accumulating species and do not unspecifically incorporate selenium into proteins. The purification and biochemical characterization of a selenocysteine methyltransferase from cultured Astragalus bisculatus cells is described, which does not accept cysteine as a substrate. We propose that this enzyme plays a crucial role in conferring selenium tolerance.
189 citations
180 citations
TL;DR: Hydrogen peroxide metabolism in soybean embryonic axes during early inhibition appears to have the following main features: mitochondrial membranes are the most important source of cytosolic O2- and H2O2; and extracellular peroxidase located at the cell wall affords an enzymatic system able to use diffused H 2O2.
168 citations
TL;DR: The dietary selenium intakes of a young couple residing in Southern California were determined to be 107 and 99 micrograms/day for the husband and the wife, respectively, on the basis of a 30 day study, and glutathione peroxidase blood levels did not correlate with blood Se concentrations.
160 citations
"Oxidative stress during selenium de..." refers background in this paper
...Experimental Se deficiency in animals has been widely studied (14-17), which indicates reversible and specific Se-dependent enzyme modulation in a variety of species....
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TL;DR: Compared to the bovine erythrocyte enzyme, a number of residues in the active site are mutated or deleted in the plasma enzyme, including all the residues that were previously suggested to be involved in glutathione binding.
158 citations