Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P30044 (antioxidant enzyme)
 8,037 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Three terrestrial plant species, oat (Avena sativa ), Chinese cabbage (Brassica campestris cv. chinensis) and lettuce (Lactuca sativa), were exposed to different concentrations of herbicide TCA (sodium trichloroacetate) in a growth test according to guideline OECD # 208. Classical (i.e. germination and biomass) and biochemical (i.e., antioxydant enzyme activities) endpoints were investigated. Germination rate decreased significantly at 3.9 mg TCA kg dry soil(-1) (for oat and lettuce) and 62.5 mg TCA kg dry soil(-1) (for Chinese cabbage). Biomass decreased significantly only at 1.9 mg TCA kg dry soil(-1) (for oat and lettuce) and 15.6 mg TCA kg dry soil(-1) (for Chinese cabbage). The activities of superoxide dismutase (EC 1.15.1.1), catalase (EC 1.11.1.6), peroxidase (EC 1.11.1.7) and glutathione reductase (EC 1.6.4.2) increased significantly at the lowest concentration of TCA tested, i.e. 0.03 mg TCA kg dry soil(-1) (for oat and lettuce) and 0.48 mg TCA kg dry soil(-1) (for Chinese cabbage). Our results showed a ranking of sensitivity among the different endpoints for the three plant species: enzyme activities>biomass>germination rate. The increase in antioxidant enzyme activities observed in this study ensured the detoxification of increased levels of active oxygen species, and presumably prevented the plants from undergoing oxidative stress damage. Thus, the use of enzyme activities will permit the detection of early injury in plant growth testing.
Environ Exp Bot 2000 Nov 01
PMID:Classical and biochemical endpoints in the evaluation of phytotoxic effects caused by the herbicide trichloroacetate. 1106 42

Sunflower (Helianthus annuus L. cv. SH222) plants and calli were exposed to KCl stress for three weeks. Calli were more tolerant to KCl than plants. KCl stress decreased NO(-)(3), Mn, Fe and B levels in whole plants and P, Ca and Mg in shoots. NO(-)(3), P, Ca, Mg, Mn, and B levels decreased in 100 mM-stressed calli. Chlorophyll content, F:(m) and (F:(m)-F:(0))/F:(m) ratio decreased in stressed leaves, while F:(0) increased only in leaves exposed to severe stress (100 and 150 mM). Membrane permeability and lipid peroxidation increased in plants under all stress conditions and in 100 and 150 mM stressed calli, but remained unchanged in 25 mM stressed calli. Salt stress also induced changes relating to antioxidant enzymes: plants under all stress conditions showed a decrease in catalase, peroxidase and SOD activities. Calli under moderate stress (25 mM KCl) showed an increase of catalase, peroxidase and SOD activities, but the activities of peroxidase and SOD decreased when calli were exposed to higher KCl concentrations. The decrease of antioxidant enzyme activities is in tune with lipid peroxidation and membrane permeability increases. On the other hand, calli adapted for 6 months to 100 mM KCl showed an increase of these enzyme activities compared to unstressed calli, while MDA production and membrane permeability were not significantly affected.
J Exp Bot 2001 Feb
PMID:In situ and in vitro senescence induced by KCl stress: nutritional imbalance, lipid peroxidation and antioxidant metabolism. 1128 80

This study examined the effect of increasing chloroplastic superoxide dismutase (SOD), ascorbate peroxidase (APX), or glutathione reductase (GR) activity via plant transformation of cotton on the initial recovery of photosynthesis following exposures to 10 degrees C and high photon flux density (PFD). Growing wild-type or non-expressing segregate plants (controls) and transformants at two PFDs (600 micromol m(-2) s(-1) and full sun) resulted in a range of total antioxidant enzyme activities. Total SOD activities above that for control leaves grown in full sun did not substantially improve the recoveries of CO(2)-saturated photosynthesis, especially for stress treatments lasting more than 1 h, while elevated APX or GR activity did improve recoveries after 1-3 h of the chilling treatment. No synergistic effects were noted when the activities of more than one antioxidant enzyme were elevated in transgenic hybrids. Although these results suggest that the protection of photosynthesis can be realized by reducing either superoxide or H(2)O(2) levels, thereby reducing the possibility of hydroxyl radical formation, the situation is complicated, since elevated APX or GR activity can improve recoveries even when additional SOD activity has no effect. In conclusion, to enhance the protection of photosynthesis using stroma-targeted antioxidant enzymes, enhancing metabolism associated with H(2)O(2) is more effective than enhancing the capacity for superoxide scavenging. Although small, the improvement in the protection of photosynthetic capacity may be sufficient to improve cotton yield in temperate regions with large diurnal temperature fluctuations.
J Exp Bot 2001 Dec
PMID:Protecting cotton photosynthesis during moderate chilling at high light intensity by increasing chloroplastic antioxidant enzyme activity. 1170 84

The regulation of the antioxidant defence system by ultraviolet-B (UV-B) was determined in a marine macroalga Ulva fasciata Delile exposed to low (0.5, 1 W m(-2)), medium (2.5, 5 W m(-2)), and high (10, 20 W m(-2)) UV-B irradiance. UV-B > or =2.5 W m(-2) increased H2O2 contents that are positively correlated with lipid peroxidation and total peroxide contents. Inhibition of the UV-B-induced H2O2 increase by a specific O2.- scavenger, 1,2-dihydroxy-benzene-3,5-disulphonic acid, shows that O2.- is the primary source of H2O2. Superoxide dismutase activity was increased by UV-B with a peak at 2.5 W m(-2), which did not match the H2O2 pattern. Alleviation of UV-B-induced oxidative damage by a H2O2 scavenger, dimethylthiourea, and a free radical scavenger, sodium benzoate, which inhibited UV-B-induced H2O2 accumulation, suggests that oxidative damage caused by UV-B > or = 2.5 W m(-2) is ascribed to accumulated H2O2. However, a decrease in growth rate and TTC reduction ability only at high UV-B doses indicates that the defence and repairing systems operate at low and medium UV-B doses. H2O2 not only can be excreted but can also be detoxified via the ascorbate-glutathione cycle. Increases in catalase, peroxidase, ascorbate peroxidase, and glutathione reductase activities and ascorbate (AsA) and glutathione pools, as well as AsA regeneration ability, function to keep the balance of cellular H2O2 under low UV-B doses. Dehydroascorbate reductase and monodehydroascorbate reductase are responsible for AsA regeneration under low and medium UV-B radiation, respectively. The appearance of oxidative damage in medium and high UV-B flux is attributable to a lower induction of the ascorbate-glutathione cycle as an antioxidant defence system. Overall, the availability of antioxidants and the induction of antioxidant enzyme activities for detoxifying reactive oxygen species (ROS) are regulated in U. fasciata against UV-B-induced oxidative stress, and experiments using ROS scavengers demonstrate that the antioxidant defence system is modulated by O2.- or H2O2.
J Exp Bot 2005 Nov
PMID:Ultraviolet-B-induced oxidative stress and responses of the ascorbate-glutathione cycle in a marine macroalga Ulva fasciata. 1615 54

Previous studies suggest that abscisic acid (ABA) stimulates the activities of antioxidant enzymes under normal and chilling temperature and enhanced chilling resistance in Stylosanthes guianensis. The objective of this study was to test whether nitric oxide (NO) is involved in the ABA-induced activities of the antioxidant enzymes in Stylosanthes guianensis due to its nature as a second messenger in stress responses. Plants were treated with NO donors, ABA, ABA in combination with NO scavengers or the nitric oxide synthase (NOS) inhibitor and their effects on the activity of antioxidant enzymes and NO production were compared. The results showed that ABA increased the activities of superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase (APX). The effect of ABA on antioxidant enzyme activities was suppressed by the NOS inhibitor, N(omega)-nitro-L-arginine (L-NNA), and the NO scavenger, 2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl3-oxide (PTIO). NO content increased after 5 h of ABA treatment. The NO-scavenger, PTIO, and the NOS-inhibitor, L-NNA, inhibited the accumulation of NO in ABA-treated Stylosanthes guianensis. NO donor treatment enhanced the activities of SOD, CAT, and APX. The results suggested that NO was involved in the ABA-induced activities of SOD, CAT, and APX in Stylosanthes guianensis. ABA triggered NO production that may lead to the stimulation of antioxidant enzyme activities.
J Exp Bot 2005 Dec
PMID:Nitric oxide is involved in abscisic acid-induced antioxidant activities in Stylosanthes guianensis. 1626 1

Ascorbate peroxidase (APX) exists as several isoforms that are found in various compartments in plant cells. The cytosolic and chloroplast APXs appear to play important roles in antioxidation metabolism in plant cells, yet the function of peroxisomal APX is not well studied. In this study, the localization of a putative peroxisomal membrane-bound ascorbate peroxidase, APX3 from Arabidopsis, was confirmed by studying the green fluorescent protein (GFP)-APX3 fusion protein in transgenic plants. GFP-APX3 was found to co-localize with a reporter protein that was targeted to peroxisomes by the peroxisomal targeting signal 1. The function of APX3 in Arabidopsis was investigated by analysing an APX3 knockout mutant under normal and several stress conditions. It was found that loss of function in APX3 does not affect Arabidopsis growth and development, suggesting that APX3 may not be an important antioxidant enzyme in Arabidopsis, at least under the conditions that were tested, or the function of APX3 could be compensated by other antioxidant enzymes in plant cells.
J Exp Bot 2006
PMID:The Arabidopsis ascorbate peroxidase 3 is a peroxisomal membrane-bound antioxidant enzyme and is dispensable for Arabidopsis growth and development. 1687 50

Increasing evidence suggests that heat acclimation and exogenous salicylic acid (SA) and abscisic acid (ABA) may lead to the enhancement of thermotolerance in plants. In this study, the roles that free SA, conjugated SA, ABA, and phosphatidylinositol-4,5-bisphosphate (PIP(2))-specific phospholipase C (PLC) play in thermotolerance development induced by heat acclimation (38 degrees C) were investigated. To evaluate their potential functions, three inhibitors of synthesis or activity were infiltrated into pea leaves prior to heat acclimation treatment. The results showed that the burst of free SA in response to heat acclimation could be attributed to the conversion of SA 2-O-D-glucose, the main conjugated form of SA, to free SA. Inhibition of ABA biosynthesis also resulted in a defect in the free SA peak during heat acclimation. In acquired thermotolerance assessment, the greatest weakness of antioxidant enzyme activity and the most severe heat injury (malondialdehyde content and degree of wilting) were found in pea leaves pre-treated with neomycin, a well-known inhibitor of PIP(2)-PLC activity. PsPLC gene expression was activated by exogenous ABA, SA treatments, and heat acclimation after pre-treatments with a SA biosynthesis inhibitor. From these results, PIP(2)-PLC appears to play a key role in free SA- and ABA-associated reinforcement of thermotolerance resulting from heat acclimation.
J Exp Bot 2006
PMID:Novel interrelationship between salicylic acid, abscisic acid, and PIP2-specific phospholipase C in heat acclimation-induced thermotolerance in pea leaves. 1690 2

The effects of exogenous abscisic acid (ABA) on the acclimation of Picea asperata to water deficit were investigated in two populations originating from wet and dry climate regions of China. Exogenous ABA was sprayed onto the leaves, and changes in plant growth and structure, gas exchange, water use efficiency (WUE), endogenous ABA content, and antioxidant enzyme levels were monitored. The results demonstrated that ABA application affected the two P. asperata populations in different ways during the water deficit. ABA application resulted in significantly lower CO(2) assimilation rates (A) under water deficit in plants from the wet climate population, whereas there were no significant changes in this parameter in the dry climate population. On the other hand, ABA application significantly decreased the dry shoot biomass, stomatal conductance (g(s)), transpiration rate (E), and malondialdehyde (MDA) content, and it significantly increased the leaf mass per area (LMA), root/shoot ratio (Rs), fine root/total root ratio (Ft), WUE, ABA content, and the superoxide dismutase (SOD), ascorbate peroxidase (APX), and catalase (CAT) activities under water-deficit conditions in the dry climate population, whereas ABA application did not significantly affect these parameters in the wet climate population. The results clearly demonstrated that sensitivity to an exogenous ABA application is population-dependent in P. asperata. Direct evidence is presented that variation in physiological mechanisms rather than different rates of ABA absorption explain the population differentiation in the sensitivity to exogenous ABA, and that the physiological basis for the amplified response to water deficit caused by exogenous ABA, present mainly in the dry climate population, is related to internal ABA accumulation. These results provide evidence for adaptive differentiation between populations of P. asperata, and they support the expected relationship between environmental heterogeneity and the magnitude of plastic responses in plant populations.
J Exp Bot 2007
PMID:Interactions between water deficit, ABA, and provenances in Picea asperata. 1790 Nov 94

Soybeans (Glycine max Merr.) were grown at elevated carbon dioxide concentration ([CO(2)]) or chronic elevated ozone concentration ([O(3)]; 90 ppb), and then exposed to an acute O(3) stress (200 ppb for 4 h) in order to test the hypothesis that the atmospheric environment alters the total antioxidant capacity of plants, and their capacity to respond to an acute oxidative stress. Total antioxidant metabolism, antioxidant enzyme activity, and antioxidant transcript abundance were characterized before, immediately after, and during recovery from the acute O(3) treatment. Growth at chronic elevated [O(3)] increased the total antioxidant capacity of plants, while growth at elevated [CO(2)] decreased the total antioxidant capacity. Changes in total antioxidant capacity were matched by changes in ascorbate content, but not phenolic content. The growth environment significantly altered the pattern of antioxidant transcript and enzyme response to the acute O(3) stress. Following the acute oxidative stress, there was an immediate transcriptional reprogramming that allowed for maintained or increased antioxidant enzyme activities in plants grown at elevated [O(3)]. Growth at elevated [CO(2)] appeared to increase the response of antioxidant enzymes to acute oxidative stress, but dampened and delayed the transcriptional response. These results provide evidence that the growth environment alters the antioxidant system, the immediate response to an acute oxidative stress, and the timing over which plants return to initial antioxidant levels. The results also indicate that future elevated [CO(2)] and [O(3)] will differentially affect the antioxidant system.
J Exp Bot 2011 May
PMID:Growth at elevated ozone or elevated carbon dioxide concentration alters antioxidant capacity and response to acute oxidative stress in soybean (Glycine max). 2128 25

The mitogen-activated protein kinase (MAPK) cascade plays pivotal roles in diverse signalling pathways related to plant development and stress responses. In this study, the cloning and functional characterization of a group-I MAPK gene, PtrMAPK, in Poncirus trifoliata (L.) Raf are reported. PtrMAPK contains 11 highly conserved kinase domains and a phosphorylation motif (TEY), and is localized in the nucleus of transformed onion epidermal cells. The PtrMAPK transcript level was increased by dehydration and cold, but was unaffected by salt. Transgenic overexpression of PtrMAPK in tobacco confers dehydration and drought tolerance. The transgenic plants exhibited better water status, less reactive oxygen species (ROS) generation, and higher levels of antioxidant enzyme activity and metabolites than the wild type. Interestingly, the stress tolerance capacity of the transgenic plants was compromised by inhibitors of antioxidant enzymes. In addition, overexpression of PtrMAPK enhanced the expression of ROS-related and stress-responsive genes under normal or drought conditions. Taken together, these data demonstrate that PtrMAPK acts as a positive regulator in dehydration/drought stress responses by either regulating ROS homeostasis through activation of the cellular antioxidant systems or modulating transcriptional levels of a variety of stress-associated genes.
J Exp Bot 2011 Oct
PMID:Cloning and molecular characterization of a mitogen-activated protein kinase gene from Poncirus trifoliata whose ectopic expression confers dehydration/drought tolerance in transgenic tobacco. 2177 84


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