Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:1.6.5.4 (SOR)
720 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Three-year-old 'Zaozhong No. 6' loquat (Eriobotrya japonica Lindl.) seedlings were foliar-sprayed with 0.2, 0.5, 1.0 and 1.5 mmol x L(-1) of sodium nitroprusside (SNP), subjected to low temperature (-3 degrees) stress for 6 hours, and then cultured at 25 degrees C for four days. The antioxidant metabolites and enzymes in the seedling leaves were determined 0, 1, and 4 days after recovery. Comparing with the control (water spraying), all SNP treatments had a decreased H2O2 content but an increased content of glutathione (GSH) and ascorbic acid (AsA) and increased activity of ascorbate peroxidase (APX), glutathione reductase (GR), dehydroascorbate reductase (DHAR) and monodehydroascorbate reductase (MDAR) in the seedling leaves. Four days after recovery, the H2O2 content in the seedling leaves treated with 0.5 mmol x L(-1) of SNP decreased by 75.53%, while the GSH and AsA contents and the APX, GR, DHAR and MDAR activities were increased by 29.12%, 23.40%, 50.0%, 44.4%, 49.53%, and 62.68%, respectively. All of these suggested that appropriate dosage of exogenous NO could enhance the activity of antioxidant system in loquat leaves and alleviated the cell injury of loquat leaves under low temperature stress. In this study, the appropriate dosage of NO was 0.5 mmol x L(-1) of SNP.
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PMID:[Effects of exogenous NO on ascorbate-glutathione cycle in loquat leaves under low temperature stress]. 1979 50

An open-top chamber experiment was conducted to study the effects of high concentration O3 (80 nmol x mol(-1)) on the superoxide anion radical (O2*-) generation rate, hydrogen peroxide (H2O2) content, activities of superoxide dismutase (SOD), ascorbate peroxidase (APX), dehydroascorbate reductase (DHAR), monodehydroascorbate reductase (MDHAR) and glutathione reductase (GR), and ascorbic acid content in Pinus tabulaeformis leaves. Under high concentration O3 exposure, the superoxide anion radical generation rate and H2O2 and malondialdehyde (MDA) contents increased, while the ascorbic acid content and the activities of SOD, APX, DHAR, MDHAR, and GR increased in early growth season but decreased then to a level lower than the control, which illustrated that the antioxidant system of P. tabulaeformis did respond in an acclimation way in the early growth season, but could not bear the damage of long-term elevated O3 exposure.
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PMID:[Effects of elevated O3 concentration on anti-oxidative enzyme activities in Pinus tabulaeformis]. 1980 56

In Arabidopsis thaliana, oxidant-induced signalling has been shown to utilize the mitogen-activated protein kinase (MAPK), AtMPK6. To identify proteins whose accumulation is altered by ozone in an AtMPK6-dependent manner we employed isotope-coded affinity tagging (ICAT) technology to investigate the impact of AtMPK6-suppression on the protein profiles in Arabidopsis both before (air control) and during continuous ozone (O(3)) fumigation (500 nL L(-1) for 8 h). Among the 150 proteins positively identified and quantified in the O(3)-treated plants, we identified thirteen proteins whose abundance was greater in the AtMPK6-suppressed genotype than in wild-type (WT). These include the antioxidant proteins, monodehydroascorbate reductase, peroxiredoxin Q, and glutathione reductase. A further eighteen proteins were identified whose abundance was lower in the ozone-treated AtMPK6-suppressed line relative to ozone-exposed WT plants. These predominantly comprised proteins involved in carbohydrate-, energy-, and amino acid metabolism, and tetrapyrrole biosynthesis. In control plants, five proteins increased, and nine proteins decreased in abundance in the AtMPK6-suppressed genotype compared to that of the WT, reflecting changes in the protein composition of plants that have AtMPK6 constitutively suppressed. Since a number of these proteins are part of the redox response pathway, and loss of AtMPK6 renders Arabidopsis more susceptible to oxidative stress, we propose that AtMPK6 plays a key role in the plant's overall ability to manage oxidative stress.
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PMID:Quantitative proteomics identifies oxidant-induced, AtMPK6-dependent changes in Arabidopsis thaliana protein profiles. 1981 38

When comparing the responses of two wheat (Triticum aestivum L.) genotypes, the drought-tolerant Plainsman V and the drought-sensitive Cappelle Desprez, to reduced amounts of irrigation water, we found differences in ascorbate metabolism: both ascorbate oxidation and transcription levels of enzymes processing ascorbate were changed. Relative transcript levels of ascorbate peroxidase (APX), monodehydroascorbate reductase (MDAR), dehydroascorbate reductase (DHAR) and glutathione reductase (GR) isoenzymes, predicted to localize in distinct subcellular organelles, showed different transcriptional changes in the two genotypes. Among APX coding mRNAs, expression levels of two cytosolic (cAPX I, II) and a thylakoid-bound (tAPX) variants increased significantly in Plainsman V while a cytosolic (cAPX I) and a stromal (sAPX II) APX coding transcripts were found to be higher in Cappelle Desprez after a 4-week-long water-deficit stress. Examining the MDARs, two cytosolic isoforms (cMDAR I, II) displayed significant up-regulation of mRNA levels in the sensitive genotype, whereas only one of them (cMDAR II) did in the tolerant cultivar. We found an up-regulated chloroplastic DHAR (chlDHAR) mRNA only in the sensitive Cappelle Desprez. However, increased expression levels of a cytosolic GR (cGR) and a chloroplastic GR (chlGR) were detected only in the tolerant Plainsman V. After 4 weeks of reduced irrigation, a significantly lower ascorbate/dehydroascorbate ratio was detected in leaves of the sensitive Cappelle Desprez than in the tolerant Plainsman V. Our results indicate that more robust transcription of ascorbate-based detoxification machinery may prevent an adverse shift of the cellular redox balance.
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PMID:Transcriptional differences in gene families of the ascorbate-glutathione cycle in wheat during mild water deficit. 1990 15

The present study suggests the importance of reactive oxygen species (ROS) and antioxidant metabolites as biochemical signals during the beneficial interactions of mitochondrial metabolism with photosynthetic carbon assimilation at saturating light and optimal CO2. Changes in steady-state photosynthesis of pea mesophyll protoplasts monitored in the presence of antimycin A [AA, inhibitor of cytochrome oxidase (COX) pathway] and salicylhydroxamic acid [SHAM, inhibitor of alternative oxidase (AOX) pathway] were correlated with total cellular ROS and its scavenging system. Along with superoxide dismutase (SOD) and catalase (CAT), responses of enzymatic components--ascorbate peroxidase (APX), monodehydroascorbate reductase (MDAR), glutathione reductase (GR) and non-enzymatic redox components of ascorbate-glutathione (Asc-GSH) cycle, which play a significant role in scavenging cellular ROS, were examined in the presence of mitochondrial inhibitors. Both AA and SHAM caused marked reduction in photosynthetic carbon assimilation with concomitant rise in total cellular ROS. Restriction of electron transport through COX or AOX pathway had differential effect on ROS generating (SOD), ROS scavenging (CAT and APX) and antioxidant (Asc and GSH) regenerating (MDAR and GR) enzymes. Further, restriction of mitochondrial electron transport decreased redox ratios of both Asc and GSH. However, while decrease in redox ratio of Asc was more prominent in the presence of SHAM in light compared with dark, decrease in redox ratio of GSH was similar in both dark and light. These results suggest that the maintenance of cellular ROS at optimal levels is a prerequisite to sustain high photosynthetic rates which in turn is regulated by respiratory capacities of COX and AOX pathways.
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PMID:Importance of ROS and antioxidant system during the beneficial interactions of mitochondrial metabolism with photosynthetic carbon assimilation. 1994 71

Spartina densiflora is an invasive cordgrass that is colonizing new habitats and ousting indigenous species in pro-oxidative environments like cadmium-polluted salt marshes in the Odiel estuary (Spain). The aim of our study was to characterize its antioxidative system in order to find out if the system underlies the tolerance of S. densiflora to cadmium toxicity. S. densiflora plants were firstly evaluated to ascertain its antioxidative status in the natural habitat and then they were cultured in the laboratory in unpolluted sand for 28 days. Throughout this period, plants acclimatized and oxidative stress markers reached stable low levels. Then, S. densiflora plants were exposed to cadmium concentrations (10, 100 and 1000 microM Cd) for another 28 days. Higher Cd content in leaves was related to higher level of reactive oxygen species (ROS) causing important oxidative cell damage (lipid peroxidation and lower chlorophyll content). However, S. densiflora possesses a well-organized and appropriately modulated antioxidative defense system which comprises enzymatic activities of guaiacol peroxidase (EC 1.11.1.7), catalase (EC 1.11.1.6), ascorbate peroxidase (EC 1.11.1.11) and superoxide dismutase (EC 1.15.1.1) coupled with the activation of the ascorbate cycle, including enzymatic activities of glutathione reductase (EC 1.6.4.2), dehydroascorbate reductase (EC 1.8.5.1) and monodehydroascorbate reductase (EC 1.6.5.4). This activation was sufficient to reduce Cd-induced ROS accumulation and oxidative damage caused by the lowest Cd-concentrations, but not by the highest Cd-concentration (1000 microM). Nevertheless, the antioxidant system seems to be efficient to achieve a tolerance to cadmium toxicity, allowing normal plant development, even at the presence of highest Cd concentration.
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PMID:Cadmium-induced oxidative stress and the response of the antioxidative defense system in Spartina densiflora. 2021 Aug 72

Organic wastes such as sewage sludge have been successfully used to increase crop productivity of horticultural soils. Nevertheless, considerations of the impact of sludges on vegetable and fruit quality have received little attention. Therefore, the objective of the present work was to investigate the impact of two sanitized sewage sludges, autothermal thermophilic aerobic digestion (ATAD) and compost sludge, on the growth, yield, and fruit quality of pepper plants ( Capsicum annuum L. cv. Piquillo) grown in the greenhouse. Two doses of ATAD (15 and 30% v/v) and three of composted sludge (15, 30, and 45%) were applied to a peat-based potting mix. Unamended substrate was included as control. ATAD and composted sludge increased leaf, shoot, and root dry matter, as well as fruit yield, mainly due to a higher number of fruits per plant. There was no effect of sludge on fruit size (dry matter per fruit and diameter). The concentrations of Zn and Cu in fruit increased with the addition of sewage sludges. Nevertheless, the levels of these elements remained below toxic thresholds. Pepper fruits from sludge-amended plants maintained low concentrations of capsaicin and dihydrocapsaicin, thus indicating low pungency level, in accordance with the regulations prescribed by the Control Board of "Lodosa Piquillo peppers" Origin Denomination. The application of sludges did not modify the concentration of vitamin C (ASC) in fruit, whereas the highest doses of composted sludge tended to increase the content of reduced (GSH) and oxidized (GSSG) glutathione, without change in the GSH/GSSG ratio. There were no effects of sludge on the transcript levels of enzymes involved in the synthesis of vitamin C, l-galactono-1,4-lactone dehydrogenase (GLDH) or in the ascorbate-glutathione cycle, ascorbate peroxidase (APX), monodehydroascorbate reductase (MDAR), and glutathione reductase (GR). Results suggest that the synthesis and degradation of ASC and GSH were compensated for in most of the treatments assayed. The application of sanitized sludges to pepper plants can improve pepper yield without loss of food nutritional quality, in terms of fruit size and vitamin C, glutathione, and capsaicinoid contents.
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PMID:Growth, yield, and fruit quality of pepper plants amended with two sanitized sewage sludges. 2045 Jan 96

Wheat (Triticum aestivum L.) seedlings of a drought-resistant cv. C306 were subjected to severe water deficit directly or through stress cycles of increasing intensity with intermittent recovery periods. The antioxidant defense in terms of redox metabolites and enzymes in root cells and mitochondria was examined in relation to membrane damage. Acclimated seedlings exhibited higher relative water content and were able to limit the accumulation of H(2)O(2) and membrane damage during subsequent severe water stress conditions. This was due to systematic up-regulation of superoxide dismutase, ascorbate peroxidase (APX), catalase, peroxidases, and ascorbate-glutathione cycle components at both the whole cell level as well as in mitochondria. In contrast, direct exposure of severe water stress to non-acclimated seedlings caused greater water loss, excessive accumulation of H(2)O(2) followed by elevated lipid peroxidation due to the poor antioxidant enzyme response particularly of APX, monodehydroascorbate reductase, dehydroascorbate reductase, glutathione reductase, and ascorbate-glutathione redox balance. Mitochondrial antioxidant defense was found to be better than the cellular defense in non-acclimated roots. Termination of stress followed by rewatering leads to a rapid enhancement in all the antioxidant defense components in non-acclimated roots, which suggested that the excess levels of H(2)O(2) during severe water stress conditions might have inhibited or down-regulated the antioxidant enzymes. Hence, drought acclimation conferred enhanced tolerance toward oxidative stress in the root tissue of wheat seedlings due to both reactive oxygen species restriction and well-coordinated induction of antioxidant defense.
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PMID:Antioxidant response of wheat roots to drought acclimation. 2055 54

Abstract The ascorbate-dependent antioxidative system was studied in leaves of barley infected with the barley powdery mildew fungus Blumeria graminis f.sp. hordei (Bgh). Increased ascorbate peroxidase (APX) activity was detected upon infection, especially in the compatible interaction. APX activity was determined in epidermal and total leaf tissues. A relatively higher increase in APX activity was found in the epidermis compared to total leaf 72 h after inoculation in the compatible interaction, but the increase was not restricted to the epidermis. Activity assays in native gels and Northern blot hybridization indicated that the increase in APX activity was caused by a cytosolic APX isoform. 'Inverse Northern blot' hybridization results with the cDNA of a cytosolic APX supported the relatively higher increase in epidermal APX activity compared to total leaf activity. In the compatible interaction, monodehydroascorbate reductase (MDHAR) activity increased in temporal and spatial patterns similar to that of APX activity. In contrast to this, dehydroascorbate reductase and glutathione reductase activities either decreased or were unaffected by Bgh infection. The increase in APX and MDHAR activities in the compatible interaction continued until severe infection of the leaves. Thus, an up-regulation of the antioxidative system of the host cells could play a role for maintenance of the biotrophic relationship between Bgh and the barley leaf by preventing proliferating oxidative processes, which would otherwise be harmful to the living plant cell on which the biotrophic powdery mildew fungus depends.
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PMID:Up-regulation of the ascorbate-dependent antioxidative system in barley leaves during powdery mildew infection. 2057 77

The effect of acidified calcium sulfate (ACS) on the quality of litchi ( Litchi chinensis Sonn. cv. 'Brewster') fruit after harvest was evaluated. ACS at 1.25% or higher concentrations significantly inhibited the activities of polyphenol oxidase and peroxidase in the pericarp during storage at both 5 and 10 degrees C. These treatments also effectively prevented browning and retained the red color of the outer shell of the fruit. Total phenolic and total anthocyanin contents in pericarp were increased by ACS treatments in a dose-dependent manner. The radical scavenging activities for ROO(*), DPPH(*), (*)OH and O(2)(*-) were also enhanced by ACS, particularly by 2.5 and 5% concentrations. The activities of several antioxidant enzymes and enzymes of ascorbate-glutathione cycle including catalase, ascorbate peroxidase, glutathione peroxidase, glutathione reductase, dehydroascorbate reductase, and monodehydroascorbate reductase gradually declined during storage. However, ACS enhanced the activities of these enzymes, especially at the beginning of the storage. Samples treated with ACS generally had higher flavonoid levels than the control. The three major flavonoids, cyanidin-3-rutinoside, cyanidin-3-glucoside and quercetin-3-rutinoside, were found to be significantly increased by 2.5 and 5.0% ACS at both 5 and 10 degrees C. No differences were detected among various treatments in soluble solids content or sugar and organic acid levels in the pulp of litchi fruit, indicating that the internal quality of the fruit was not adversely affected by ACS treatment.
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PMID:Maintaining quality of litchi fruit with acidified calcium sulfate. 2061 5


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