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.
Abstract: Higher plants are considered not to require selenium (Se). However, it has recently been shown that Se increases the antioxidative capacity and stress tolerance of lettuce (Lactuca sativa L.) and ryegrass (Lolium perenne L.). This research was undertaken to investigate the antioxidative properties of Se during photooxidative stress in potato (Solanum tuberosum L.) and to determine the defence mechanisms. Potato plants were exposed to 600 μmol/m2/s light intensity at low temperature (4 °C) or paraquat-mediated oxidative stress. The stress responses were monitored by measuring chlorophyll content and following changes in chlorophyll fluorescence and membrane ion leakage. Moreover, the effects of Se on the transcript levels of chloroplast CuZnSOD, mitochondrial MnSOD, glutathione peroxidase (GPX), and psbA were analyzed using northern hybridization. Se supplementation improved the recovery of chlorophyll content following light stress. After prolonged exposure to light, the reduction of Fv/Fm was slightly lower compared with plants cultivated without additional Se. The photosynthesis of Se treated plants was somewhat more tolerant of paraquat and the integrity of membranes was improved during oxidative stress. Se altered transcript accumulation of chloroplast CuZnSOD and GPX but the MnSOD and psbA transcript levels were unaffected. The results suggest that Se is an antioxidant or it activates protective mechanisms, which can alleviate oxidative stress in the chloroplasts.
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
References
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TL;DR: In this article, the catalytic activity of catalase has been investigated using ultraviolet (UV) spectrophotometry and Titrimetric methods, which is suitable for comparative studies for large series of measurements.
Abstract: Publisher Summary Catalase exerts a dual function: (1) decomposition of H 2 O 2 to give H 2 O and O 2 (catalytic activity) and (2) oxidation of H donors, for example, methanol, ethanol, formic acid, phenols, with the consumption of 1 mol of peroxide (peroxide activity) The kinetics of catalase does not obey the normal pattern Measurements of enzyme activity at substrate saturation or determination of the K s is therefore impossible In contrast to reactions proceeding at substrate saturation, the enzymic decomposition of H 2 O 2 is a first-order reaction, the rate of which is always proportional to the peroxide concentration present Consequently, to avoid a rapid decrease in the initial rate of the reaction, the assay must be carried out with relatively low concentrations of H 2 O 2 (about 001 M) This chapter discusses the catalytic activity of catalase The method of choice for biological material, however, is ultraviolet (UV) spectrophotometry Titrimetric methods are suitable for comparative studies For large series of measurements, there are either simple screening tests, which give a quick indication of the approximative catalase activity, or automated methods
20,238 citations
TL;DR: The staining procedure for localizing superoxide dismutase on polyacrylamide electrophoretograms has been applied to extracts obtained from a variety of sources and could thus be assayed either in crude extracts or in purified protein fractions.
Abstract: Nitro blue tetrazolium has been used to intercept O2− generated enzymically or photochemically. The reduction of NBT by O2− has been utilized as the basis of assays for superoxide dismutase, which exposes its presence by inhibiting the reduction of NBT. Superoxide dismutase could thus be assayed either in crude extracts or in purified protein fractions. The assays described are sensitive to ng/ml levels of super-oxide dismutase and were applicable in free solution or on polyacrylamide gels. The staining procedure for localizing superoxide dismutase on polyacrylamide electrophoretograms has been applied to extracts obtained from a variety of sources. E. coli has been found to contain two superoxide dismutases whereas bovine heart, brain, lung, and erthrocytes contain only one.
10,933 citations
TL;DR: Observations confirm that the electron donor for the scavenging of hydrogen peroxide in chloroplasts is L-ascorbate and that the L-ASCorbate is regenerated from DHA by the system: photosystem I-*ferredoxin-*NADP^>glutathione and a preliminary characterization of the chloroplast peroxidase is given.
Abstract: Intact spinach chloroplasts scavenge hydrogen peroxide with a peroxidase that uses a photoreductant as the electron donor, but the activity of ruptured chloroplasts is very low [Nakano and Asada (1980) Plant & Cell Physiol. 21: 1295]. Ruptured spinach chloroplasts recovered their ability to photoreduce hydrogen peroxide with the concomitant evolution of oxygen after the addition of glutathione and dehydroascorbate (DHA). In ruptured chloroplasts, DHA was photoreduced to ascorbate and oxygen was evolved in the process in the presence of glutathione. DHA reductase (EC 1.8.5.1) and a peroxidase whose electron donor is specific to L-ascorbate are localized in chloroplast stroma. These observations confirm that the electron donor for the scavenging of hydrogen peroxide in chloroplasts is L-ascorbate and that the L-ascorbate is regenerated from DHA by the system: photosystem I-*ferredoxin-*NADP^>glutathione. A preliminary characterization of the chloroplast peroxidase is given.
8,406 citations
"Oxidative stress during selenium de..." refers methods in this paper
...The unit of enzyme activity was defined as 1 gmol of ODA oxidized per minute at 30~ Ascorbate peroxidase activity was assayed by the method of Nakano and Asada (28) by following the oxidation of ascorbate to dehydroascorbate at 290 nm....
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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
"Oxidative stress during selenium de..." refers background or methods in this paper
...Glutathione peroxidase (GSH-Px), a well-recognized selenoenzyme in animal systems, is effective in the removal of H202 as well as various organoperoxides (3) and phospholipid hydroperoxides (4)....
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...Isoenzymes of peroxidase are found in most higher plants (39) and their functions include (1) secondary cell-wall biosynthesis (40), (2) wound healing, and (3) resistance against infection by pathogens (41)....
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...0 ppm and mimosine at 1 mM were indicated by: (1) an enhanced state 4 rate with all the substrates tested, (2) RCR being similar to the stressed controls, and (3) with cytochrome c oxidase activity almost undetectable in the mimosine group (1 raM)....
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...foenum-graecum during Se deficiency, (2) enhanced mitochondrial functional efficiency mediated by Se and mimosine independently, and (3) an antioxidative role for mimosine during Se deficiency....
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...heme peroxidases, which remove H202, the selenoenzyme GSH-Px (Se-GSH-Px) effectively scavenges H202 in low concentrations and also removes other organoperoxides (3)....
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TL;DR: These low molecular mass antioxidant molecules add significantly to the defense provided by the enzymes superoxide dismutase, catalase and glutathione peroxidases, which are termed ‘oxidative stress’.
Abstract: An imbalance between oxidants and antioxidants in favour of the oxidants, potentially leading to damage, is termed 'oxidative stress'. Oxidants are formed as a normal product of aerobic metabolism but can be produced at elevated rates under pathophysiological conditions. Antioxidant defense involves several strategies, both enzymatic and non-enzymatic. In the lipid phase, tocopherols and carotenes as well as oxy-carotenoids are of interest, as are vitamin A and ubiquinols. In the aqueous phase, there are ascorbate, glutathione and other compounds. In addition to the cytosol, the nuclear and mitochondrial matrices and extracellular fluids are protected. Overall, these low molecular mass antioxidant molecules add significantly to the defense provided by the enzymes superoxide dismutase, catalase and glutathione peroxidases.
4,485 citations