Cloning and characterization of an ascorbate peroxidase gene ...

African Journals Online (AJOL)

DR. NJ TONUKARI

2012-05-29

May 29, 2012 ... Real-time quantitative polymerase chain reaction was used to explore expression patterns of. MaAPX1 in ... and the activity of a number of enzymatic systems, including ... peroxidase (APX), glutathione reductase and catalase.

Mechanism of melatonin protection against copper-ascorbate-induced oxidative damage in vitro through isothermal titration calorimetry.

Science.gov (United States)

Ghosh, Arnab K; Naaz, Shamreen; Bhattacharjee, Bharati; Ghosal, Nirajan; Chattopadhyay, Aindrila; Roy, Souvik; Reiter, Russel J; Bandyopadhyay, Debasish

2017-07-01

Involvement of oxidative stress in cardiovascular diseases is well established. Melatonin's role as an antioxidant and free radical scavenger via its receptor dependent and receptor independent pathways is well known. The aim of this study is to identify and elaborate upon a third mechanism by which melatonin is able to abrogate oxidative stress. Oxidative stress was induced in vitro, by copper (0.2mM)-ascorbate (1mM) in isolated goat heart mitochondria, cytosol and peroxisomes and they were co-incubated with graded doses of melatonin. Similar experiments in a cell-free chemical system involving two pure antioxidant enzymes, Cu-Zn superoxide dismutase and catalase was also carried out. Biochemical changes in activity of these antioxidant enzymes were analysed. Isothermal titration calorimetric studies with pure Cu-Zn superoxide dismutase and catalase were also carried out. Incubation with copper-ascorbate led to alteration in activity of Cu-Zn superoxide dismutase and catalase which were found to be protected upon co-incubation with melatonin (80μM for catalase and 1μM for others). Results of isothermal titration calorimetric studies with pure Cu-Zn superoxide dismutase and catalase along with different combinations of copper chloride, ascorbic acid and melatonin suggest that when melatonin is present in the reaction medium along with copper-ascorbate, it restrains the copper-ascorbate molecules by binding with them physically along with scavenging the free radicals generated by them. The present study suggests that possibly, binding of melatonin with antioxidant enzymes masks the vulnerable sites of these antioxidant enzymes, thus preventing oxidative damage by copper-ascorbate molecules. Copyright © 2017 Elsevier Inc. All rights reserved.

Influence of radiation damage repair inhibitor on superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) in different sensitive crops

International Nuclear Information System (INIS)

Song Daojun; Xu Dengyi; Wan Zhaoliang; He Shoulin

1997-01-01

The activities of superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) were affected remarkably by 60 Co γ-ray irradiation and radiation damage repair inhibitor (Caf, EDTA). SOD, CAT and POD activities showed the similar change pattern in both soybean (sensitive to radiation) and Brassica napus L. (resistant to radiation) seedlings in all treatments. After reaching the maximum value, SOD activity decreased with the increase of doses. CAT activity had the same change pattern as that of SOD in soybean, while with Brassica napus L., CAT activity remained relatively steady from 300 Gy to 1000 Gy. And POD activity increased with the increase of doses. Compared with H 2 O-treatments, CaF, EDAT post-treatments obviously enhanced SOD, CAT and POD activities. With all the treatments, the three enzyme activities were higher in Brassica napus L. than those in soybean seedlings

Effect of γ-radiation on the activities of superoxide dimutase, catalase and peroxidase on the germinating wheat grain (Triticum aestivum,L.)

International Nuclear Information System (INIS)

Chakraborti, M.; Chatterjee, G.C.

1983-01-01

Effect of γ-radiation on several enzymes like catalase, peroxidase and superoxide dismutase in different parts of germinating wheat seeds has been studied. It was found that superoxide dismutase activity under the influence of γ-radiation was highest in the embryo part and showed maximum activity, 24 hours after germination. The activity exhibited a gradual decline with time. catalase and peroxidase, the stimulatory efect being maximum in the case of catalase activity. The catalase and peroxidase activities were found to be maximally localised in the embryo part and the highest value was attained after 72 hrs. in the case of catalase and after 48 hrs in the case of peroxidase activity. The results indicate that γ-radiation stimulates free radical generation in the embryo along with subsequent increase in the activities of superoside dismutase, catalase and peroxidase. (author)

Comparison of defence responses to Botrytis cinerea infection in tomato plants propagated in vitro and grown in vivo

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Jacek Patykowski

2013-12-01

Full Text Available Defence reactions: O2 - generation, superoxide dismutase, catalase, guaiacol peroxidase and ascorbate peroxidase activities after B. cinerea infection in tomato plants propagated in vitro and grown in vivo have been compared. Infection resulted in rapid O2 - generation. Superoxide dismutase activity increase was slower than O2 - response. In plants propagated in vitro catalase and guaiacol peroxidase activities after infection were induced less strongly than in plants grown in vivo. K2HPO4 pretreatment of plants grown in vitro enhanced significantly the activities of catalase and guaiacol peroxidase after infection. Slight restriction of B. cinerea infection development in in vitro propagated plants pretreated with K2HP04 was observed.

Unveiling the water-associated conformational mobility in the active site of ascorbate peroxidase.

Science.gov (United States)

Chao, Wei-Chih; Lin, Li-Ju; Lu, Jyh-Feng; Wang, Jinn-Shyan; Lin, Tzu-Chieh; Chen, Yi-Han; Chen, Yi-Ting; Yang, Hsiao-Ching; Chou, Pi-Tai

2018-03-01

We carried out comprehensive spectroscopic studies of wild type and mutants of ascorbate peroxidase (APX) to gain understanding of the conformational mobility of the active site. In this approach, three unnatural tryptophans were applied to replace the distal tryptophan (W41) in an aim to probe polarity/water environment near the edge of the heme-containing active site. 7-azatryptophan ((7-aza)Trp) is sensitive to environment polarity, while 2,7-azatryptophan ((2,7-aza)Trp) and 2,6-diazatryptophan ((2,6-aza)Trp) undergo excited-state water-catalyzed double and triple proton transfer, respectively, and are sensitive to the water network. The combination of their absorption, emission bands and the associated relaxation dynamics of these fluorescence probes, together with the Soret-band difference absorption and resonance Raman spectroscopy, lead us to unveil the water associated conformational mobility in the active site of APX. The results are suggestive of the existence of equilibrium between two different environments surrounding W41 in APX, i.e., the water-rich and water-scant forms with distinct fluorescence relaxation. Our results thus demonstrate for the first time the power of integrating multiple sensors (7-aza)Trp, (2,7-aza)Trp and (2,6-aza)Trp in probing the water environment of a specifically targeted Trp in proteins. Copyright © 2017 Elsevier B.V. All rights reserved.

Seasonal variation of oxidative biomarkers in gills and digestive gland of green-lipped mussel Perna viridis from Arabian Sea

Digital Repository Service at National Institute of Oceanography (India)

Verlecar, X.N.; Jena, K.B.; Chainy, G.B.N.

peroxidation (LPX), hydrogen peroxide (H sub(2) O sub(2)), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPX), glutathione transferase (GST), glutathione reductase (GR), reduced glutathione (GSH) and ascorbic acid (ASA) were measured...

Peroxidase enzymes regulate collagen extracellular matrix biosynthesis.

Science.gov (United States)

DeNichilo, Mark O; Panagopoulos, Vasilios; Rayner, Timothy E; Borowicz, Romana A; Greenwood, John E; Evdokiou, Andreas

2015-05-01

Myeloperoxidase and eosinophil peroxidase are heme-containing enzymes often physically associated with fibrotic tissue and cancer in various organs, without any direct involvement in promoting fibroblast recruitment and extracellular matrix (ECM) biosynthesis at these sites. We report herein novel findings that show peroxidase enzymes possess a well-conserved profibrogenic capacity to stimulate the migration of fibroblastic cells and promote their ability to secrete collagenous proteins to generate a functional ECM both in vitro and in vivo. Mechanistic studies conducted using cultured fibroblasts show that these cells are capable of rapidly binding and internalizing both myeloperoxidase and eosinophil peroxidase. Peroxidase enzymes stimulate collagen biosynthesis at a post-translational level in a prolyl 4-hydroxylase-dependent manner that does not require ascorbic acid. This response was blocked by the irreversible myeloperoxidase inhibitor 4-amino-benzoic acid hydrazide, indicating peroxidase catalytic activity is essential for collagen biosynthesis. These results suggest that peroxidase enzymes, such as myeloperoxidase and eosinophil peroxidase, may play a fundamental role in regulating the recruitment of fibroblast and the biosynthesis of collagen ECM at sites of normal tissue repair and fibrosis, with enormous implications for many disease states where infiltrating inflammatory cells deposit peroxidases. Copyright © 2015 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.

Apple and quince peroxidase activity in response to essential oils ...

African Journals Online (AJOL)

Jane

2011-09-28

Sep 28, 2011 ... activities of edible coatings enriched with natural plant extracts such as rosemary ..... its oxidation by ascorbate peroxidase activity (Talano et al., 2008). ... delicious and quince improved the antioxidant protection of the fruits ...

Molecular Modeling of Peroxidase and Polyphenol Oxidase: Substrate Specificity and Active Site Comparison

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Lalida Shank

2010-09-01

Full Text Available Peroxidases (POD and polyphenol oxidase (PPO are enzymes that are well known to be involved in the enzymatic browning reaction of fruits and vegetables with different catalytic mechanisms. Both enzymes have some common substrates, but each also has its specific substrates. In our computational study, the amino acid sequence of grape peroxidase (ABX was used for the construction of models employing homology modeling method based on the X-ray structure of cytosolic ascorbate peroxidase from pea (PDB ID:1APX, whereas the model of grape polyphenol oxidase was obtained directly from the available X-ray structure (PDB ID:2P3X. Molecular docking of common substrates of these two enzymes was subsequently studied. It was found that epicatechin and catechin exhibited high affinity with both enzymes, even though POD and PPO have different binding pockets regarding the size and the key amino acids involved in binding. Predicted binding modes of substrates with both enzymes were also compared. The calculated docking interaction energy of trihydroxybenzoic acid related compounds shows high affinity, suggesting specificity and potential use as common inhibitor to grape ascorbate peroxidase and polyphenol oxidase.

Effects of silicon on plant resistance to environmental stresses: review

Science.gov (United States)

Balakhnina, T.; Borkowska, A.

2013-03-01

The role of exogenous silicon in enhancing plant resistance to various abiotic stressors: salinity, drought, metal toxicities and ultraviolet radiation are presented. The data on possible involvement of silicon in reducing the reactive oxygen species generation, intensity of lipid peroxidation, and in some cases, increasing the activity of enzymes of the reactive oxygen species detoxificators: superoxide dismutase, ascorbate peroxidase, glutathione reductase, guaiacol peroxidase and catalase are analyzed.

Waterlogging pretreatment during vegetative growth improves tolerance to waterlogging after anthesis in wheat

DEFF Research Database (Denmark)

Li, Chengyong; Jiang, Dong; Wollenweber, Bernd

2011-01-01

plants due to high maximum and actual quantum yield (Fv/Fm, ΦPSII); (3) increasing activities of superoxide dismutase (SOD), ascorbate peroxidase (APX) and catalase (CAT); (4) enhancing dry matter accumulation after anthesis and its contribution to grain mass, which further resulting in significantly...

Ectopic expression of a horseradish peroxidase enhances growth rate and increases oxidative stress resistance in hybrid aspen.

Science.gov (United States)

Kawaoka, Akiyoshi; Matsunaga, Etsuko; Endo, Saori; Kondo, Shinkichi; Yoshida, Kazuya; Shinmyo, Atsuhiko; Ebinuma, Hiroyasu

2003-07-01

We previously demonstrated that overexpression of the horseradish (Armoracia rusticana) peroxidase prxC1a gene stimulated the growth rate of tobacco (Nicotiana tabacum) plants. Here, the cauliflower mosaic virus 35S::prxC1a construct was introduced into hybrid aspen (Populus sieboldii x Populus grandidentata). The growth rate of these transformed hybrid aspen plants was substantially increased under greenhouse conditions. The average stem length of transformed plants was 25% greater than that of control plants. There was no other obvious phenotypic difference between the transformed and control plants. Fast-growing transformed hybrid aspen showed high levels of expression of prxC1a and had elevated peroxidase activities toward guaiacol and ascorbate. However, there was no increase of the endogenous class I ascorbate peroxidase activities in the transformed plants by separate assay and activity staining of native polyacrylamide gel electrophoresis. Furthermore, calli derived from the transformed hybrid aspen grew faster than those from control plants and were resistant to the oxidative stress imposed by hydrogen peroxide. Therefore, enhanced peroxidase activity affects plant growth rate and oxidative stress resistance.

Response of tropical trees to sulphur dioxide stress and recovery

Energy Technology Data Exchange (ETDEWEB)

Vartshney, C.K.; Mitra, I. [Jawaharlal Nehru University, New Delhi (India). School of Environmental Sciences

1995-12-31

Ethylene emission, ascorbic acid content, peroxidase and superoxide dismutase activity were measured in four tropical tree species. Six month old saplings of Morus alba Linn., Azadirachta indica A.Juss., Melia-azadirach Linn. and Syzgium jambolina Lamk, were exposed to 0.5 ppm SO{sub 2} for four hours for six consecutive days. Recovery from SO{sub 2} stress was followed for twelve days after termination of the fumigation. SO{sub 2} induced foliar ethylene emission increased during fumigation but declined following termination of fumigation. SO{sub 2} fumigation enhanced the activities of superoxide dismutase and peroxidase in all four species. Their activities, however, declined on withdrawal of SO{sub 2} stress. Ascorbic acid content decreased due to SO{sub 2} stress but exhibited recovery on termination of fumigation. The response of the four plant species was widely different both during the fumigation period and during post-fumigation recovery regime. 26 refs., 3 figs., 2 tabs.

Oxidation of eugenol by purified human term placental peroxidase.

Science.gov (United States)

Zhang, R; Kulkarni, K A; Kulkarni, A P

2000-01-01

The oxidation of eugenol by purified human term placental peroxidase (HTPP) was examined. Spectral analyses indicated that, similar to horseradish peroxidase, HTPP is capable of catalyzing the oxidation of eugenol. The accumulated stable product in the reaction medium due to eugenol oxidation by HTPP was tentatively identified as quinone methide of eugenol (EQM). The EQM formation exhibited a pH optimum of 8.0 and was dependent on incubation time, amount of HTPP and the concentration of both eugenol and hydrogen peroxide. The specific activity of approx 2.8 micromoles of EQM/min/mg protein was observed with different preparations of HTPP. The EQM formation was significantly suppressed by glutathione and ascorbic acid. The classical peroxidase inhibitors viz. potassium cyanide and sodium azide blocked the reaction in a concentration manner. Collectively, the results suggest that eugenol may undergo peroxidative metabolism in human placenta. Copyright 2000 Harcourt Publishers Ltd.

Ectopic over-expression of peroxisomal ascorbate peroxidase (SbpAPX) gene confers salt stress tolerance in transgenic peanut (Arachis hypogaea).

Science.gov (United States)

Singh, Natwar; Mishra, Avinash; Jha, Bhavanath

2014-08-15

Peroxisomal ascorbate peroxidase gene (SbpAPX) of an extreme halophyte Salicornia brachiata imparts abiotic stress endurance and plays a key role in the protection against oxidative stress. The cloned SbpAPX gene was transformed to local variety of peanut and about 100 transgenic plants were developed using optimized in vitro regeneration and Agrobacterium mediated genetic transformation method. The T0 transgenic plants were confirmed for the gene integration; grown under controlled condition in containment green house facility; seeds were harvested and T1 plants were raised. Transgenic plants (T1) were further confirmed by PCR using gene specific primers and histochemical GUS assay. About 40 transgenic plants (T1) were selected randomly and subjected for salt stress tolerance study. Transgenic plants remained green however non-transgenic plants showed bleaching and yellowish leaves under salt stress conditions. Under stress condition, transgenic plants continued normal growth and completed their life cycle. Transgenic peanut plants exhibited adequate tolerance under salt stress condition and thus could be explored for the cultivation in salt affected areas for the sustainable agriculture. Copyright © 2014 Elsevier B.V. All rights reserved.

Low activity of superoxide dismutase and high activity of glutathione reductase in erythrocytes from centenarians

DEFF Research Database (Denmark)

Andersen, Helle Raun; Jeune, B; Nybo, H

1998-01-01

aged between 60 and 79 years. MEASUREMENTS: enzyme activities of superoxide dismutase (CuZn-SOD), glutathione peroxidase, catalase and glutathione reductase (GR) in erythrocytes. Functional capacity among the centenarians was evaluated by Katz' index of activities of daily living, the Physical...

Overexpression of Iron Superoxide Dismutase in Transformed Poplar Modifies the Regulation of Photosynthesis at Low CO2 Partial Pressures or Following Exposure to the Prooxidant Herbicide Methyl Viologen1

Science.gov (United States)

Arisi, Ana-Carolina M.; Cornic, Gabriel; Jouanin, Lise; Foyer, Christine H.

1998-01-01

Chloroplast-targeted overexpression of an Fe superoxide dismutase (SOD) from Arabidopsis thaliana resulted in substantially increased foliar SOD activities. Ascorbate peroxidase, glutathione reductase, and monodehydroascorbate reductase activities were similar in the leaves from all of the lines, but dehydroascorbate reductase activity was increased in the leaves of the FeSOD transformants relative to untransformed controls. Foliar H2O2, ascorbate, and glutathione contents were comparable in all lines of plants. Irradiance-dependent changes in net CO2 assimilation and chlorophyll a fluorescence quenching parameters were similar in all lines both in air (21% O2) and at low (1%) O2. CO2-response curves for photosynthesis showed similar net CO2-exchange characteristics in all lines. In contrast, values of photochemical quenching declined in leaves from untransformed controls at intercellular CO2 (Ci) values below 200 μL L−1 but remained constant with decreasing Ci in leaves of FeSOD transformants. When the O2 concentration was decreased from 21 to 1%, the effect of FeSOD overexpression on photochemical quenching at limiting Ci was abolished. At high light (1000 μmol m−2 s−1) a progressive decrease in the ratio of variable (Fv) to maximal (Fm) fluorescence was observed with decreasing temperature. At 6oC the high-light-induced decrease in the Fv/Fm ratio was partially prevented by low O2 but values were comparable in all lines. Methyl viologen caused decreased Fv/Fm ratios, but this was less marked in the FeSOD transformants than in the untransformed controls. These observations suggest that the rate of superoxide dismutation limits flux through the Mehler-peroxidase cycle in certain conditions. PMID:9625709

Oxidative Stress in The Hippocampus During Experimental Seizures Can Be Ameliorated With The Antioxidant Ascorbic Acid

Directory of Open Access Journals (Sweden)

Ítala Mônica Sales Santos

2009-01-01

Full Text Available Ascorbic acid has many nonenzymatic actions and is a powerful water-soluble antioxidant. It protects low density lipoproteins from oxidation and reduces harmful oxidants in the central nervous system. Pilocarpine-induced seizures have been suggested to be mediated by increases in oxidative stress. Current studies have suggested that antioxidant compounds may afford some level of neuroprotection against the neurotoxicity of seizures. The objective of the present study was to evaluate the neuroprotective effects of ascorbic acid (AA in rats, against the observed oxidative stress during seizures induced by pilocarpine. Wistar rats were treated with 0.9% saline (i.p., control group, ascorbic acid (500 mg/kg, i.p., AA group, pilocarpine (400 mg/kg, i.p., pilocarpine group, and the association of ascorbic acid (500 mg/kg, i.p. plus pilocarpine (400 mg/kg, i.p., 30 min before of administration of ascorbic acid (AA plus pilocarpine group. After the treatments all groups were observed for 6 h. The enzyme activities as well as the lipid peroxidation and nitrite concentrations were measured using spectrophotometric methods and the results compared to values obtained from saline and pilocarpine-treated animals. Protective effects of ascorbic acid were also evaluated on the same parameters. In pilocarpine group there was a significant increase in lipid peroxidation and nitrite level. However, no alteration was observed in superoxide dismutase and catalase activities. Antioxidant treatment significantly reduced the lipid peroxidation level and nitrite content as well as increased the superoxide dismutase and catalase activities in hippocampus of adult rats after seizures induced by pilocarpine. Our findings strongly support the hypothesis that oxidative stress in hippocampus occurs during seizures induced by pilocarpine, proving that brain damage induced by the oxidative process plays a crucial role in seizures pathogenic consequences, and also imply that a

Exogenous melatonin suppresses dark-induced leaf senescence by activating the superoxide dismutase-catalase antioxidant pathway and down-regulating chlorophyll degradation in excised leaves of perennial ryegrass (Lolium perenne L.

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Jing Zhang

2016-10-01

Full Text Available Leaf senescence is a typical symptom in plants exposed to dark and may be regulated by plant growth regulators. The objective of this study was to determine whether exogenous application of melatonin (N-acetyl-5-methoxytryptamine suppresses dark-induced leaf senescence and the effects of melatonin on reactive oxygen species (ROS scavenging system and chlorophyll degradation pathway in perennial grass species. Mature perennial ryegrass (Lolium perenne L. cv. ‘Pinnacle’ leaves were excised and incubated in 3 mM 2-(N-morpholino ethanesulfonic buffer (pH 5.8 supplemented with melatonin or water (control and exposed to dark treatment for 8 d. Leaves treated with melatonin maintained significantly higher endogenous melatonin level, chlorophyll content, photochemical efficiency, and cell membrane stability expressed by lower electrolyte leakage and malondialdehyde (MDA content compared to the control. Exogenous melatonin treatment also reduced the transcript level of chlorophyll degradation-associated genes and senescence marker genes (LpSAG12.1, Lph36, and Lpl69 during the dark treatment. The endogenous O2- production rate and H2O2 content were significantly lower in these excised leaves treated with melatonin compared to the water control. Exogenous melatonin treatment caused increases in enzymatic activity and transcript levels of superoxide dismutase and catalase but had no significant effects on ascorbate peroxidase, glutathione reductase, dehydroascorbate reductase, and monohydroascorbate reductase. The content of non-enzymatic antioxidants, such as ascorbate and dehydroascorbate, were decreased by melatonin treatment, while the content of glutathione and oxidized glutathione was not affected by melatonin. These results suggest that the suppression of dark-induced leaf senescence by exogenous melatonin may be associated with its roles in regulating ROS scavenging through activating the superoxide dismutase-catalase enzymatic antioxidant

Changes in element accumulation, phenolic metabolism, and antioxidative enzyme activities in the red-skin roots of Panax ginseng.

Science.gov (United States)

Zhou, Ying; Yang, Zhenming; Gao, Lingling; Liu, Wen; Liu, Rongkun; Zhao, Junting; You, Jiangfeng

2017-07-01

Red-skin root disease has seriously decreased the quality and production of Panax ginseng (ginseng). To explore the disease's origin, comparative analysis was performed in different parts of the plant, particularly the epidermis, cortex, and/or fibrous roots of 5-yr-old healthy and diseased red-skin ginseng. The inorganic element composition, phenolic compound concentration, reactive oxidation system, antioxidant concentrations such as ascorbate and glutathione, activities of enzymes related to phenolic metabolism and oxidation, and antioxidative system particularly the ascorbate-glutathione cycle were examined using conventional methods. Aluminum (Al), iron (Fe), magnesium, and phosphorus were increased, whereas manganese was unchanged and calcium was decreased in the epidermis and fibrous root of red-skin ginseng, which also contained higher levels of phenolic compounds, higher activities of the phenolic compound-synthesizing enzyme phenylalanine ammonia-lyase and the phenolic compound oxidation-related enzymes guaiacol peroxidase and polyphenoloxidase. As the substrate of guaiacol peroxidase, higher levels of H 2 O 2 and correspondingly higher activities of superoxide dismutase and catalase were found in red-skin ginseng. Increased levels of ascorbate and glutathione; increased activities of l-galactose 1-dehydrogenase, ascorbate peroxidase, ascorbic acid oxidase, and glutathione reductase; and lower activities of dehydroascorbate reductase, monodehydroascorbate reductase, and glutathione peroxidase were found in red-skin ginseng. Glutathione- S -transferase activity remained constant. Hence, higher element accumulation, particularly Al and Fe, activated multiple enzymes related to accumulation of phenolic compounds and their oxidation. This might contribute to red-skin symptoms in ginseng. It is proposed that antioxidant and antioxidative enzymes, especially those involved in ascorbate-glutathione cycles, are activated to protect against phenolic compound

A combination of ascorbic acid and α-tocopherol or a combination of Mg and Zn are both able to reduce the adverse effects of lindane-poisoning on rat brain and liver.

Science.gov (United States)

Hfaiedh, Najla; Murat, Jean-Claude; Elfeki, Abdelfettah

2012-10-01

The purpose of this study, carried out on male Wistar rats, was to evaluate the beneficial effects of supplementation with ascorbic acid (Vit C) and α-tocopherol (Vit E) or with Mg and Zn upon lindane-induced damages in liver and brain. Under our experimental conditions, lindane poisoning (5mg/kg body weight per day for 3 days) resulted in (1) an increased level of plasma glucose, cholesterol and triglycerides, (2) an increased activity of LDH, ALP, AST, ALT, (3) an oxidative stress in liver and brain as revealed by an increased level of lipids peroxidation (TBARS) and a decrease of glutathione-peroxidase, superoxide dismutase and catalase activities in liver and brain. In conclusion, both Vit C+E or Mg+Zn treatments display beneficial effects upon oxidative stress induced by lindane treatment in liver and brain. Copyright © 2012 Elsevier GmbH. All rights reserved.

In vivo inhibition of tumor progression by 5 hydroxy-1,4-naphthoquinone (juglone) and 2-(4-hydroxyanilino)-1,4-naphthoquinone (Q7) in combination with ascorbate

Energy Technology Data Exchange (ETDEWEB)

Ourique, Fabiana [Department of Biochemistry, Universidade Federal de Santa Catarina (UFSC), Florianópolis, SC (Brazil); Kviecinski, Maicon R. [Postgraduate Programe of Health Science, Universidade do Sul de Santa Catarina (UNISUL), Palhoça, SC (Brazil); Zirbel, Guilherme; Castro, Luiza S.E.P.W.; Gomes Castro, Allisson Jhonatan; Mena Barreto Silva, Fátima Regina [Department of Biochemistry, Universidade Federal de Santa Catarina (UFSC), Florianópolis, SC (Brazil); Valderrama, Jaime A.; Rios, David; Benites, Julio [Department of Chemical and Pharmaceutical Sciences, Universidad Arturo Prat, Iquique (Chile); Calderon, Pedro Buc [Toxicology and Cancer Biology Research Group (GTOX), Louvain Drug Research Institute, Université Catholique de Louvain, Brussels (Belgium); Pedrosa, Rozangela Curi, E-mail: rozangelapedrosa@gmail.com [Department of Biochemistry, Universidade Federal de Santa Catarina (UFSC), Florianópolis, SC (Brazil)

2016-09-02

The purpose of the study was to obtain further in vivo data of antitumor effects and mechanisms triggered by juglone and Q7 in combination with ascorbate. The study was done using Ehrlich ascites tumor-bearing mice. Treatments were intraperitoneal every 24 h for 9 days. Control group was treated with excipient. Previous tests selected the doses of juglone and Q7 plus ascorbate (1 and 100 mg/kg, respectively). Samples of ascitic fluid were collected to evaluate carbonyl proteins, GSH and activity of antioxidant enzymes such as catalase, superoxide dismutase, glutathione peroxidase and glutathione reductase. Hypoxia inducible factor HIF-1α, GLUT1, proteins driving cell cycle (p53, p16 and cyclin A) and apoptosis (poly-ADP-polymerase PARP, Bax and Bcl-xL) were assessed by western blot. Tumor cells were categorized by the phase of cell cycle using flow cytometry and type of cell death using acridine orange/ethidium bromide. A glucose uptake assessment was performed by liquid scintillation using Ehrlich tumor cells cultured with {sup 14}C-deoxyglucose. Treatments caused increased protein carbonylation and activity of antioxidant enzymes and decreased levels of GSH, HIF-1α, GLUT1 and glucose uptake in tumor cells. They also caused increased number of tumor cells in G1, p53 and p16 activation and decreased cyclin A, but only when combined with ascorbate. Apoptosis was induced mostly when treatments were done with ascorbate, causing PARP and Bax cleavage, and increased Bax/Bcl-xL ratio. Juglone and Q7 in combination with ascorbate caused inhibition of tumor progress in vivo by triggering apoptosis and cell cycle arrest associated with oxidative stress, suppression of HIF-1 and uncoupling of glycolytic metabolism. - Highlights: • Ascorbate potentiates the inhibition caused by juglone and Q7on tumor progress in vivo. • Juglone and Q7 with ascorbate caused widespread oxidative stress in tumor tissue. • Treatments inhibited HIF-1 and GLUT1 expression causing

Oxidative status, in vitro iron-induced lipid oxidation and superoxide dismutase, catalase and glutathione peroxidase activities in rhea meat.

Science.gov (United States)

Terevinto, A; Ramos, A; Castroman, G; Cabrera, M C; Saadoun, A

2010-04-01

Rhea (Rhea americana) muscles Obturatorius medialis (OM) Iliotibialis lateralis (IL) and Iliofibularis (I), obtained from farmed animals, were evaluated regarding their oxidative/antioxidant status. The mean level of thiobarbituric acid reactive substances (TBARS) expressed as malonaldehyde (MDA) content was of 0.84 mg MDA/kg wet tissue for the three muscles. TBARS level was significantly higher in IL than OM and I, with the two latter showing similar levels. The mean level of carbonyl proteins expressed as dinitrophenylhydrazine (DNPH) was 1.59 nmol DNPH mg(-1). Carbonyl protein levels were significantly different (POM>I). Iron-induced TBARS generation was not significantly different between the three muscles at any time, nor for each muscle during the 5 h of the experiment. Superoxide dismutase activity in IL muscle was significantly higher (P<0.05) than in I muscle. However, the difference between IL and OM muscles was not significant. The differences between the three muscles became not significant when the results were expressed by mg of protein contained in the extract, instead by g of wet tissue. No differences were found for catalase (micromol of discomposed H(2)O(2) min(-1) g(-1) wet tissue or by mg of protein contained in the extract) and glutathione peroxidase (micromol ol of oxidized NADPH min(-1) g(-1) of wet tissue or by mg of protein contained in the extract) activities between the three muscles. 2009 Elsevier Ltd. All rights reserved.

Defense Responses to Mycotoxin-Producing Fungi Fusarium proliferatum, F. subglutinans, and Aspergillus flavus in Kernels of Susceptible and Resistant Maize Genotypes.

Science.gov (United States)

Lanubile, Alessandra; Maschietto, Valentina; De Leonardis, Silvana; Battilani, Paola; Paciolla, Costantino; Marocco, Adriano

2015-05-01

Developing kernels of resistant and susceptible maize genotypes were inoculated with Fusarium proliferatum, F. subglutinans, and Aspergillus flavus. Selected defense systems were investigated using real-time reverse transcription-polymerase chain reaction to monitor the expression of pathogenesis-related (PR) genes (PR1, PR5, PRm3, PRm6) and genes protective from oxidative stress (peroxidase, catalase, superoxide dismutase and ascorbate peroxidase) at 72 h postinoculation. The study was also extended to the analysis of the ascorbate-glutathione cycle and catalase, superoxide dismutase, and cytosolic and wall peroxidases enzymes. Furthermore, the hydrogen peroxide and malondialdehyde contents were studied to evaluate the oxidation level. Higher gene expression and enzymatic activities were observed in uninoculated kernels of resistant line, conferring a major readiness to the pathogen attack. Moreover expression values of PR genes remained higher in the resistant line after inoculation, demonstrating a potentiated response to the pathogen invasions. In contrast, reactive oxygen species-scavenging genes were strongly induced in the susceptible line only after pathogen inoculation, although their enzymatic activity was higher in the resistant line. Our data provide an important basis for further investigation of defense gene functions in developing kernels in order to improve resistance to fungal pathogens. Maize genotypes with overexpressed resistance traits could be profitably utilized in breeding programs focused on resistance to pathogens and grain safety.

The Effect of Fasting on the Concentration of Enzimatic Antioxidants (Superoxide Dismutase and Glutathione Peroxidase in Rats

Directory of Open Access Journals (Sweden)

Muliatul Jannah

2016-06-01

Full Text Available Introduction: Consumption of excessive calories can increase the incidence of degenerative diseases mediated by ROS. Caloric restriction, have been shown to increase levels of antioxidants superoxide dismutase (SOD and Gluthatione Peroxidase (GPx. Fasting like Ramadan fasting (FLRF is a form of calorie restriction, but its effect on levels of SOD and GPx remains unclear. Objectives: to investigate the effect of fasting on levels of SOD and GPx. Methods: in a post-test only control group design, sample of 24 rats Sprague Dawley Rats aged 3-month-old, weighing 250-300 grams, were randomly divided into 4 groups. Group 1 (P-70, 2 (P-100, and 3 (P-140 were fasted for 6 hours/day, each group received of 70%, 100% and 140% calories respectively. Group 4 (C-AL received 100% calories, ad libitum. Day 16 blood was taken and levels of SOD and GPx were determined by ELISA. Data were analyzed using one-way ANOVAs, followed by post hoc LSD tests, p<0.05 was considered statistically significant. Results: the results showed that the levels of SOD and GPx occur significant differences between the groups, p = 0.000. The test results post hoc SOD (318.64 and GPx (89.16 group P-70, compared with group C-AL (278.60 and 57.20 was significantly higher (p = 0.00. SOD and GPx P-70 group compared with the group P-140 (92.03 and 48.79, significantly higher (p = 0.00. Compared with group P-100 (296.70 and 75.71 SOD and GPx in group P-70 was significantly higher, p = 0.000. Conclusion: Fasting with calorie intake of 70% and 100% for 15 days can increases levels of SOD and GPx in male rats.

Physiology response of fourth generation saline resistant soybean (Glycine max (L.) Merrill) with application of several types of antioxidants

Science.gov (United States)

Manurung, I. R.; Rosmayati; Rahmawati, N.

2018-02-01

Antioxidant applications are expected to reduce the adverse effects of soil saline. This research was conducted in plastic house, Plant Tissue Laboratory Faculty of Agriculture and Plant Physiology Laboratory Faculty of Mathematic and Natural Science, Universitas Sumatera Utara, Medan also in Research Centers and Industry Standardization, Medan from July-December 2016. The objective of the research was to know the effect of various antioxidant treatments with different concentrations (control, ascorbic acid 250, 500 and 750 ppm; salicylic acid 250, 500 and 750 ppm; α-tocopherol 250, 500 and 750 ppm) on fourth generation soybean physiology in saline condition (Electric Conductivity 5-6 dS/m). The results of this research showed that the antioxidant type and concentration affected not significantly to physiology of fourth generation soybean. Descriptively the highest average of superoxide dismutase and peroxide dismutase was showed on ascorbic acid 250 ppm. The highest average of ascorbate peroxidase was showed on α-tocopherol 750 ppm. The highest average of carotenoid content was showed on ascorbic acid 500 ppm. The highest average of chlorophyll content was showed on α-tocopherol 250 ppm. The highest average of ratio of K/Na was showed on salicylic acid 250 ppm.

Size-dependent tuning of horseradish peroxidase bioreactivity by gold nanoparticles

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Wu, Haohao; Liu, Yi; Li, Meng; Chong, Yu; Zeng, Mingyong; Lo, Y. Martin; Yin, Jun-Jie

2015-02-01

Molecules with diverse biological functions, such as heme peroxidases, can be useful tools for identifying potential biological effects of gold nanoparticles (AuNPs) at the molecular level. Here, using UV-Vis, circular dichroism, dynamic light scattering, and electron spin resonance spectroscopy, we report tuning of horseradish peroxidase (HRP) bioactivity by reactant-free AuNPs with diameters of 5, 10, 15, 30 and 60 nm (Au-5 nm, Au-10 nm, Au-15 nm, Au-30 nm and Au-60 nm). HRP conjugation to AuNPs was observed with only Au-5 nm and Au-10 nm prominently increasing the α-helicity of the enzyme to extents inversely related to their size. Au-5 nm inhibited both HRP peroxidase activity toward 3,3',5,5'-tetramethylbenzidine and HRP compound I/II reactivity toward 5,5-dimethyl-1-pyrroline N-oxide. Au-5 nm enhanced the HRP peroxidase activity toward ascorbic acid and the HRP compound I/II reactivity toward redox-active residues in the HRP protein moiety. Further, Au-5 nm also decreased the catalase- and oxidase-like activities of HRP. Au-10 nm showed similar, but weaker effects, while Au-15 nm, Au-30 nm and Au-60 nm had no effect. Results suggest that AuNPs can size-dependently enhance or inhibit HRP bioreactivity toward substrates with different redox potentials via a mechanism involving extension of the HRP substrate access channel and decline in the redox potentials of HRP catalytic intermediates.Molecules with diverse biological functions, such as heme peroxidases, can be useful tools for identifying potential biological effects of gold nanoparticles (AuNPs) at the molecular level. Here, using UV-Vis, circular dichroism, dynamic light scattering, and electron spin resonance spectroscopy, we report tuning of horseradish peroxidase (HRP) bioactivity by reactant-free AuNPs with diameters of 5, 10, 15, 30 and 60 nm (Au-5 nm, Au-10 nm, Au-15 nm, Au-30 nm and Au-60 nm). HRP conjugation to AuNPs was observed with only Au-5 nm and Au-10 nm prominently increasing the �

Low Ascorbic Acid in the vtc-1 Mutant of Arabidopsis Is Associated with Decreased Growth and Intracellular Redistribution of the Antioxidant System1

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Veljovic-Jovanovic, Sonja D.; Pignocchi, Cristina; Noctor, Graham; Foyer, Christine H.

2001-01-01

Ascorbic acid has numerous and diverse roles in plant metabolism. We have used the vtc-1 mutant of Arabidopsis, which is deficient in ascorbate biosynthesis, to investigate the role of ascorbate concentration in growth, regulation of photosynthesis, and control of the partitioning of antioxidative enyzmes. The mutant possessed 70% less ascorbate in the leaves compared with the wild type. This lesion was associated with a slight increase in total glutathione but no change in the redox state of either ascorbate or glutathione. In vtc-1, total ascorbate in the apoplast was decreased to 23% of the wild-type value. The mutant displayed much slower shoot growth than the wild type when grown in air or at high CO2 (3 mL L−1), where oxidative stress is diminished. Leaves were smaller, and shoot fresh weight and dry weight were lower in the mutant. No significant differences in the light saturation curves for CO2 assimilation were found in air or at high CO2, suggesting that the effect on growth was not due to decreased photosynthetic capacity in the mutant. Analysis of chlorophyll a fluorescence quenching revealed only a slight effect on non-photochemical energy dissipation. Hydrogen peroxide contents were similar in the leaves of the vtc-1 mutant and the wild type. Total leaf peroxidase activity was increased in the mutant and compartment-specific differences in ascorbate peroxidase (APX) activity were observed. In agreement with the measurements of enzyme activity, the expression of cytosolic APX was increased, whereas that for chloroplast APX isoforms was either unchanged or slightly decreased. These data implicate ascorbate concentration in the regulation of the compartmentalization of the antioxidant system in Arabidopsis. PMID:11598218

Ascorbic acid supplementation does not alter oxidative stress markers in healthy volunteers engaged in a supervised exercise program.

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Bunpo, Piyawan; Anthony, Tracy G

2016-02-01

The purpose of this study was to investigate the impact of ascorbic acid (AA) consumption on the oxidative stress status of untrained volunteers participating in a supervised exercise program. The study included 46 young adults (average age, 23.5 ± 0.59 years; 37 females, 9 males) who remained sedentary (n = 16) or participated in 30 min of outdoor aerobic running (n = 30) at an intensity corresponding to 65%-75% of maximum heart rate for 3 times per week for 12 weeks. Exercised subjects were randomly assigned to an exercise group without AA supplementation (control; n = 10) or received either 250 mg (n = 10) or 500 mg (n = 10) of AA supplementation previous to each exercise session. Blood samples were taken on day 0 and day 84 to evaluate metabolic profiles and antioxidant status. Sedentary subjects underwent in a single bout of aerobic running to determine total antioxidant status (TAS) and malondiadehyde (MDA) at pre- and postexercise with or without AA supplementation. No significant change in TAS was observed. Plasma MDA significantly increased at postexercise (P < 0.05), and AA supplementation decreased MDA level significantly (P < 0.05). After 3 months of exercise, there was no significant change in blood glucose, lipid profile, MDA, TAS, superoxide dismutase (SOD), glutathione peroxidase (GPx), and catalase activities amongst groups. Supplementation of AA was associated with minor and inconsistent reductions in SOD, GPx, and catalase activities (P < 0.05). These findings indicate that pre-exercise supplementation of ascorbic acid does not alter oxidative stress markers in the plasma and erythrocytes of young adults engaged in a supervised exercise program.

Biochemical parameters as biomarkers for the early recognition of environmental pollution on Scots pine trees. II. The antioxidative metabolites ascorbic acid, glutathione, {alpha}-tocopherol and the enzymes superoxide dismutase and glutathione reductase

Energy Technology Data Exchange (ETDEWEB)

Schulz, H.; Haertling, S. [UFZ Centre for Environmental Research Leipzig-Halle, Halle (Germany). Dept. of Soil Sciences

2001-10-01

Field investigations with Scots pine trees (Pinus sylvestris L.) were performed in eastern Germany, where ambient SO{sub 2}, NO{sub x} and O{sub 3} concentrations differed significantly in 1992-99 at three sites, namely Neuglobsow (yearly mean SO{sub 2} in 1992: 9 {mu}g m{sup -3}), Taura (yearly mean SO{sub 2} in 1992: 54 {mu}g m{sup -3}) and Roesa (yearly mean SO{sub 2} in 1992: 73 {mu}g m{sup -3}). To investigate the effects of SO{sub 2}, NO{sub x} and O{sub 3} on antioxidants (superoxide dismutase, ascorbic acid, glutathione, glutathione reductase, {alpha}-tocopherol) and pigments including chlorophyll fluorescence as well as visible damage symptoms in the form of needle yellowing and tip necroses, needles of the 1st and 2nd age class from young and mature trees were collected at the sites every October. Eight years after the start of the field study in 1992, the ambient SO{sub 2} concentrations had decreased significantly at Neuglobsow (yearly mean SO{sub 2} in 1999: 4 {mu}g m{sup -3}), Taura (yearly mean SO{sub 2} in 1999: 5 {mu}g m{sup -3}) and Roesa (yearly mean SO{sub 2} in 1999: 5 {mu}g m{sup -3}). NO{sub x} and O{sub 3} differed less at the three sites and showed no temporal variations. Whole needle glutathione continuously decreased, although concentrations were higher in needles of the 1st and 2nd age class from the polluted sites Taura and Roesa than the unpolluted site Neuglobsow. The activities of glutathione reductase exhibited the same site-related differences and temporal variations and were correlated with concentrations of oxidized glutathione (GSSG). In contrast, the activities of the enzyme superoxide dismutase and the concentrations of whole needle ascorbic acid remained unchanged over the period. Only at the end of the investigation period did the concentrations of oxidized ascorbic acid (dehydroascorbate) increase in six-month-old needles at the polluted sites Taura and Roesa. Despite the clear decreases in SO{sub 2}, the visible symptoms

Effect of stationary magnetic field strengths of 150 and 200 mT on reactive oxygen species production in soybean.

Science.gov (United States)

Shine, M B; Guruprasad, K N; Anand, Anjali

2012-07-01

Our previous investigation reported the beneficial effect of pre-sowing magnetic treatment for improving germination parameters and biomass accumulation in soybean. In this study, soybean seeds treated with static magnetic fields of 150 and 200 mT for 1 h were evaluated for reactive oxygen species (ROS) and activity of antioxidant enzymes. Superoxide and hydroxyl radicals were measured in embryos and hypocotyls of germinating seeds by electron paramagnetic resonance spectroscopy and kinetics of superoxide production; hydrogen peroxide and antioxidant activities were estimated spectrophotometrically. Magnetic field treatment resulted in enhanced production of ROS mediated by cell wall peroxidase while ascorbic acid content, superoxide dismutase and ascorbate peroxidase activity decreased in the hypocotyl of germinating seeds. An increase in the cytosolic peroxidase activity indicated that this antioxidant enzyme had a vital role in scavenging the increased H(2)O(2) produced in seedlings from the magnetically treated seeds. Hence, these studies contribute to our first report on the biochemical basis of enhanced germination and seedling growth in magnetically treated seeds of soybean in relation to increased production of ROS. Copyright © 2012 Wiley Periodicals, Inc.

Modulation of the Activities of Catalase, Cu-Zn, Mn Superoxide Dismutase, and Glutathione Peroxidase in Adipocyte from Ovariectomised Female Rats with Metabolic Syndrome

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Rebeca Cambray Guerra

2014-01-01

Full Text Available The aim of this study was to evaluate the association between estrogen removal, antioxidant enzymes, and oxidative stress generated by obesity in a MS female rat model. Thirty two female Wistar rats were divided into 4 groups: Control (C, MS, MS ovariectomized (Ovx, and MS Ovx plus estradiol (E2. MS was induced by administering 30% sucrose to drinking water for 24 weeks. After sacrifice, intra-abdominal fat was dissected; adipocytes were isolated and lipid peroxidation, non-enzymatic antioxidant capacity, and the activities of Cu-Zn and Mn superoxide dismutase (SOD, catalase (CAT, and glutathione peroxidase (GPx were determined. There were no significant differences in the activities of Cu-Zn, Mn SOD, CAT, and GPx between the C and MS groups, but in the MS Ovx group there was a statistically significant decrease in the activities of these enzymes when compared to MS and MS Ovx+E2. The increased lipid peroxidation and nonenzymatic antioxidant capacity found in MS Ovx was significantly decreased when compared to MS and MS Ovx+E2. In conclusion, the removal of E2 by ovariectomy decreases the activity of the antioxidant enzymes in the intra-abdominal tissue of MS female rats; this is reflected by increased lipid peroxidation and decreased nonenzymatic antioxidant capacity.

Erythrocyte superoxide dismutase, glutathione peroxidase, and catalase activities and risk of coronary heart disease in generally healthy women: a prospective study.

Science.gov (United States)

Yang, Shuman; Jensen, Majken K; Rimm, Eric B; Willett, Walter; Wu, Tianying

2014-11-01

Erythrocyte antioxidant enzymes are major circulating antioxidant enzymes in the oxidative stress defense system. Few prospective studies have assessed the association between these enzymes and the risk of coronary heart disease (CHD) in generally healthy adults. We conducted a prospective nested case-control study of CHD among 32,826 women at baseline with 15 years of follow-up from 1989 to 2004 in the Nurses' Health Study. We investigated the association of baseline erythrocyte superoxide dismutase (SOD), glutathione peroxidase (GPx), and catalase (CAT) activities with the risk of CHD. A total of 365 cases and 728 controls were included in the analysis. Overall, the relative risks of CHD associated with 1-standard deviation higher SOD, GPx, and CAT activities were 1.07 (95% confidence interval (CI): 0.94, 1.22), 1.04 (95% CI: 0.91, 1.18), and 1.04 (95% CI: 0.92, 1.17), respectively. Multivariable adjustments did not change the associations appreciably. Fasting status did not modify the associations, with the exception that SOD activity was positively associated with the risk of CHD among participants who provided blood samples within 12 hours of fasting. Overall, activities of SOD, GPx, and CAT were not associated with CHD among women who were generally healthy at the time of blood collection. © The Author 2014. Published by Oxford University Press on behalf of the Johns Hopkins Bloomberg School of Public Health. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Hydrogen peroxide induce modifications of human extracellular superoxide dismutase that results in enzyme inhibition

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Randi H. Gottfredsen

2013-01-01

Full Text Available Superoxide dismutase (EC-SOD controls the level of superoxide in the extracellular space by catalyzing the dismutation of superoxide into hydrogen peroxide and molecular oxygen. In addition, the enzyme reacts with hydrogen peroxide in a peroxidase reaction which is known to disrupt enzymatic activity. Here, we show that the peroxidase reaction supports a site-specific bond cleavage. Analyses by peptide mapping and mass spectrometry shows that oxidation of Pro112 supports the cleavage of the Pro112–His113 peptide bond. Substitution of Ala for Pro112 did not inhibit fragmentation, indicating that the oxidative fragmentation at this position is dictated by spatial organization and not by side-chain specificity. The major part of EC-SOD inhibited by the peroxidase reaction was not fragmented but found to encompass oxidations of histidine residues involved in the coordination of copper (His98 and His163. These oxidations are likely to support the dissociation of copper from the active site and thus loss of enzymatic activity. Homologous modifications have also been described for the intracellular isozyme, Cu/Zn-SOD, reflecting the almost identical structures of the active site within these enzymes. We speculate that the inactivation of EC-SOD by peroxidase activity plays a role in regulating SOD activity in vivo, as even low levels of superoxide will allow for the peroxidase reaction to occur.

Ascorbate peroxidase-related (APx-R) is not a duplicable gene.

Science.gov (United States)

Dunand, Christophe; Mathé, Catherine; Lazzarotto, Fernanda; Margis, Rogério; Margis-Pinheiro, Marcia

2011-12-01

Phylogenetic, genomic and functional analyses have allowed the identification of a new class of putative heme peroxidases, so called APx-R (APx-Related). These new class, mainly present in the green lineage (including green algae and land plants), can also be detected in other unicellular chloroplastic organisms. Except for recent polyploid organisms, only single-copy of APx-R gene was detected in each genome, suggesting that the majority of the APx-R extra-copies were lost after chromosomal or segmental duplications. In a similar way, most APx-R co-expressed genes in Arabidopsis genome do not have conserved extra-copies after chromosomal duplications and are predicted to be localized in organelles, as are the APx-R. The member of this gene network can be considered as unique gene, well conserved through the evolution due to a strong negative selection pressure and a low evolution rate. © 2011 Landes Bioscience

Effect of salicylic acid on physiological and biochemical characterization of maize grown in saline area

International Nuclear Information System (INIS)

Fahad, S.; Bano, A.

2012-01-01

The aim of the present investigation was to determine the effect of exogenously applied salicylic acid (SA) on physiology of maize (Zea mays L.) hybrid cv. 3025 grown in saline field (pH 8.4 and EC 4.2 ds/m) as well as on the nutrient status of saline soil. The salicylic acid (10/sup -5/M) was applied as foliar spray, 40 days after sowing (DAS) at vegetative stage of maize plants. The salinity significantly increased sugar contents, protein, proline and superoxide dismutase (SOD), peroxidase (POD), catalase (CAT) and ascorbate peroxidase (APOX) activities but the chlorophyll, carotenoid contents, osmotic potential and membrane stability index (MSI) were lower than the control. Foliar application of salicylic acid (SA) to salt stressed plants further augmented the sugar, protein, proline, superoxide dismutase (SOD), peroxidase (POD) ascorbate peroxidase (APOX) activities, endogenous abscisic acid (ABA) , indole acetic acid (IAA) content, and root length, fresh and dry weights of roots whereas, the chlorophyll a/b and ABA/IAA ratio were decreased. The exogenous application of SA significantly decreased the Na/sup +/, Ni/sup +3/, Pb/sup +4/, Zn/sup +2/, and Na/sup +//K/sup +/ content of soil and roots while increased the Co/sup +3/, Mn/sup +2/, Cu/sup +3/, Fe/sup +2/, K/sup +/ and Mg/sup +2/ content under salinity stress. It can be inferred that exogenous application of SA (10/sup -5/M) was effective in ameliorating the adverse effects of salinity on nutrient status of soil. SA (10/sup -5/M) can be implicated to mitigate the adverse effects of salinity on maize plants. (author)

Modulation of antioxidant defences in digestive gland of Perna viridis (L.), on mercury exposures

Digital Repository Service at National Institute of Oceanography (India)

Verlecar, X.N.; Jena, K.B.; Chainy, G.B.N.

by defense sys- tems. Antioxidant enzymes like superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPX), glutathione reductase (GR) and glutathione S-transferase (GST) and non enzymatic antioxidant molecules such as reduced glutathione (GSH...- sures include lipid peroxidation (LPX), protein carbonyl (PC), hydrogen peroxide (H 2 O 2 ), GSH, ascorbic acid (ASA) and antioxidant enzymes such as SOD, CAT, GPX, GR and GST. In addition DNA strand breaks, as an index of genotoxic stress and MT...

GST(phi) gene from Macrophyte Lemna minor is involved in cadmium exposure responses

Institute of Scientific and Technical Information of China (English)

CHEN Shihua; CHEN Xin; DOU Weihong; WANG Liang; YIN Haibo; GUO Shanli

2016-01-01

Reactive oxygen species (ROS) scavengers,including ascorbate peroxidase,superoxide dismutase,catalase and peroxidase,are the most commonly used biomarkers in assessing an organisms' response to many biotic and abiotic stresses.In this study,we cloned an 866 bp GST(phi) gene in Lemna minor and investigated its characteristics,expression and enzymatic activities under 75 μmol/L cadmium concentrations in comparison with other ROS scavengers.GST(phi) gene expression patterns were similar to those of other scavengers of ROS.This suggests that GST(phi) might be involved in responding to heavy metal (cadmium) stress and that its expression level could be used as a bio-indicator in monitoring cadmium pollution.

GST ( phi) gene from Macrophyte Lemna minor is involved in cadmium exposure responses

Science.gov (United States)

Chen, Shihua; Chen, Xin; Dou, Weihong; Wang, Liang; Yin, Haibo; Guo, Shanli

2016-03-01

Reactive oxygen species (ROS) scavengers, including ascorbate peroxidase, superoxide dismutase, catalase and peroxidase, are the most commonly used biomarkers in assessing an organisms' response to many biotic and abiotic stresses. In this study, we cloned an 866 bp GST ( phi) gene in Lemna minor and investigated its characteristics, expression and enzymatic activities under 75 μmol/L cadmium concentrations in comparison with other ROS scavengers. GST ( phi) gene expression patterns were similar to those of other scavengers of ROS. This suggests that GST ( phi) might be involved in responding to heavy metal (cadmium) stress and that its expression level could be used as a bio-indicator in monitoring cadmium pollution.

Purification and characterization of peroxidase from avocado (Persea americana Mill, cv. Hass).

Science.gov (United States)

Rojas-Reyes, José O; Robles-Olvera, Victor; Carvajal-Zarrabal, Octavio; Castro Matinez, Claudia; Waliszewski, Krzysztof N; Aguilar-Uscanga, María Guadalupe

2014-07-01

Avocado (Persea americana Mill, cv. Hass) fruit ranks tenth in terms of the most important products for Mexico. Avocado products are quite unstable due to the presence of oxidative enzymes such as polyphenol oxidase and peroxidase. The present study is to characterize the activity of purified avocado peroxidase from avocado in order to ascertain the biochemical and kinetic properties and their inhibition conditions. Purification was performed by Sephacryl S 200 HR gel filtration chromatography and its estimated molecular weight was 40 kDa. The zymogram showed an isoelectric point of 4.7. Six substrates were tested in order to ascertain the affinity of the enzyme for these substrates. The purified peroxidase was found to have low Km (0.296 mM) and high catalytic efficiency (2688 mM(-1) s(-1)) using 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid), optimum activity being reached at 51°C, pH 3.8. The addition of dithiothreitol, β-mercaptoethanol, ascorbic acid, sodium azide, L-cysteine and Tween-20 had high inhibitory effects, while metals ions such as Cu(+), Fe(2+) and Mn(2+) had weak inhibitory activity on purified avocado peroxidase. The purified avocado peroxidase exhibits high inhibition (Ki = 0.37 µM) with 1.97 µM n-propyl gallate using ABTS as substrate at 51°C, pH 3.8 for 10 min. © 2013 Society of Chemical Industry.

The antioxidative response system in Glycine max (L.) Merr. exposed to Deltamethrin, a synthetic pyrethroid insecticide

International Nuclear Information System (INIS)

Bashir, Fozia; Mahmooduzzafar; Siddiqi, T.O.; Iqbal, Muhammad

2007-01-01

Forty-five-day-old plants of Glycine max (soybean) were exposed to several Deltamethrin (synthetic pyrethroid insecticide) concentrations (0.00 %, 0.05 %, 0.10 %, 0.15 % and 0.20 %) through foliar spray in the field conditions. In the treated plants, as observed at the pre-flowering (10 DAT), flowering (45 DAT) and post-flowering (70 DAT) stages, lipid peroxidation, proline content and total glutathione content increased, whereas the total ascorbate content decreased, as compared with the control. Among the enzymatic antioxidants, activity of superoxide dismutase, ascorbate peroxidase and glutathione reductase increased significantly whereas that of catalase declined markedly in relation to increasing concentration of Deltamethrin applied. The changes observed were dose-dependent, showing a strong correlation with the degree of treatment. - The Deltamethrin-induced oxidative stress alters the ascorbate-glutathione cycle in Glycine max

Adding of ascorbic acid to the culture medium influences the antioxidant status and some biochemical parameters in the hen granulosa cells.

Science.gov (United States)

Capcarova, M; Kolesarova, A; Kalafova, A; Bulla, J; Sirotkin, A V

2015-07-01

The aim of the present study was to determine the activity of superoxide dismutase (SOD), total antioxidant status (TAS) of the hen granulosa cells, and selected biochemical parameters, including calcium, phosphorus, sodium, potassium, glucose, cholesterol, proteins, in the culture medium of granulosa cells after exposing them to ascorbic acid in vitro conditions. Ovarian granulosa cells of hens were incubated with various doses of ascorbic acid (E1 0.09 mg/ml, E2 0.13 mg/ml, E3 0.17 mg/ml, E4 0.33 mg/ml, E5 0.5 mg/ml). Ascorbic acid did not manifest antioxidant potential and higher doses of ascorbic acid (0.17; 0.33 and 0.5 mg/ml) decreased the activity of SOD in granulosa cells. Vitamin application resulted in a significantly (pascorbic acid might be involved in the regulation of selected biochemical and physiological processes in ovarian granulosa cells.

Mice Deficient in Both Mn Superoxide Dismutase and Glutathione Peroxidase-1 Have Increased Oxidative Damage and a Greater Incidence of Pathology but No Reduction in Longevity

Science.gov (United States)

Zhang, Yiqiang; Ikeno, Yuji; Qi, Wenbo; Chaudhuri, Asish; Li, Yan; Bokov, Alex; Thorpe, Suzanne R.; Baynes, John W.; Epstein, Charles; Richardson, Arlan

2009-01-01

To test the impact of increased mitochondrial oxidative stress as a mechanism underlying aging and age-related pathologies, we generated mice with a combined deficiency in two mitochondrial-localized antioxidant enzymes, Mn superoxide dismutase (MnSOD) and glutathione peroxidase-1 (Gpx-1). We compared life span, pathology, and oxidative damage in Gpx1−/−, Sod2+/−Gpx1+/−, Sod2+/−Gpx1−/−, and wild-type control mice. Oxidative damage was elevated in Sod2+/−Gpx1−/− mice, as shown by increased DNA oxidation in liver and skeletal muscle and increased protein oxidation in brain. Surprisingly, Sod2+/−Gpx1−/− mice showed no reduction in life span, despite increased levels of oxidative damage. Consistent with the important role for oxidative stress in tumorigenesis during aging, the incidence of neoplasms was significantly increased in the older Sod2+/−Gpx1−/− mice (28–30 months). Thus, these data do not support a significant role for increased oxidative stress as a result of compromised mitochondrial antioxidant defenses in modulating life span in mice and do not support the oxidative stress theory of aging. PMID:19776219

Superoxide dismutase, catalase, glutathione peroxidase and gluthatione S-transferases M1 and T1 gene polymorphisms in three Brazilian population groups.

Science.gov (United States)

de Oliveira Hiragi, Cássia; Miranda-Vilela, Ana Luisa; Rocha, Dulce Maria Sucena; de Oliveira, Silviene Fabiana; Hatagima, Ana; de Nazaré Klautau-Guimarães, Maria

2011-01-01

Antioxidants such as superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPX1) reduce the oxidation rates in the organism. Gluthatione S-transferases (GSTs) play a vital role in phase 2 of biotransformation of many substances. Variation in the expression of these enzymes suggests individual differences for the degree of antioxidant protection and geographical differences in the distribution of these variants. We described the distribution frequency of CAT (21A/T), SOD2 (Ala9Val), GPX1 (Pro198Leu), GSTM1 and GSTT1 polymorphisms in three Brazilian population groups: Kayabi Amerindians (n = 60), Kalunga Afro-descendants (n = 72), and an urban mixed population from Federal District (n = 162). Frequencies of the variants observed in Kalunga (18% to 58%) and Federal District (33% to 63%) were similar to those observed in Euro and Afro-descendants, while in Kayabi (3% to 68%), depending on the marker, frequencies were similar to the ones found in different ethnic groups. Except for SOD2 in all population groups studied here, and for GPX1 in Kalunga, the genotypic distributions were in accordance with Hardy-Weinberg Equilibrium. These data can clarify the contribution of different ethnicities in the formation of mixed populations, such as that of Brazil. Moreover, outcomes will be valuable resources for future functional studies and for genetic studies in specific populations. If these studies are designed to comprehensively explore the role of these genetic polymorphisms in the etiology of human diseases they may help to prevent inconsistent genotype-phenotype associations in pharmacogenetic studies.

Metabolismo antioxidativo: uma ferramenta para detectar pequenas diferenças no vigor de sementes de soja.

OpenAIRE

Bandeira, Juliana de Magalhães; Marini, Patrícia; Borba, Isabel Cristina Gouvea de; Martins, Andrea Bicca Noguez; Amarante, Luciano do; Moraes, Dario Munt de

2014-01-01

We aimed to differentiate the vigor of soybean seeds through antioxidant enzyme activity (superoxide dismutase-SOD, ascorbate peroxidase-APX, and catalase- CAT) and relate them to the viability and vigor standard tests to verify if these enzymes detect tenuous differences in seed vigor. The following tests were performed: germination, fi rst germination count, germination speed index, initial growth of seedlings, electrical conductivity, and respiratory and enzymatic activity. It was only pos...

Peroxidase of Brazilian Cerrado grass as an alternative for agro industrial waste treatment

Directory of Open Access Journals (Sweden)

Raquel Pinheiro Reis Souza Ramalho

2016-03-01

Full Text Available Decontamination of wastewater continues to be a challenge for society and the scientific community. Despite the availability of various materials for study, enzymes stand out due to their specificity for decomposition and biodegradability for disposal. New sources of enzymes may represent efficient and low-cost alternatives compared to routinely used techniques. In this survey, the peroxidase profile from Echinolaena inflexa fruits was studied for possible applications in the treatment of wastewater. The protein content was found to be 5.33 mg g-1. The optimum reaction conditions were: 50°C, pH 7.5 at 0.1 mol L-1 of phosphate buffer for 15 min. The enzyme was inactivated after 5 min at 94°C and was inhibited when incubated with ascorbic acid at 10 mmol L-1. In tests using phenols and agro industrial waste, the peroxidase was able to oxidase 87.5% of catechol, 67.8% of pyrogallol, 39.1% of resorcinol and still presented 29.1% of the degradation capacity of raw wastewater phenolic compounds. The results showed that the Echinolaena inflexa peroxidase, a new source of enzymes, is a potential alternative to wastewater treatment.

Proteomic and activity profiles of ascorbate-glutathione cycle enzymes in germinating barley embryo

DEFF Research Database (Denmark)

Bønsager, Birgit Christine; Shahpiri, Azar; Finnie, Christine

2010-01-01

Enzymes involved in redox control are important during seed germination and seedling growth. Ascorbate-glutathione cycle enzymes in barley embryo extracts were monitored both by 2D-gel electrophoresis and activity measurements from 4 to 144 h post imbibition (PI). Strikingly different activity...... profiles were observed. No ascorbate peroxidase (APX) activity was present in mature seeds but activity was detected after 24 h PI and increased 14-fold up to 144 h PI. In contrast, dehydroascorbate reductase (DHAR) activity was present at 4 h PI and first decreased by 9-fold until 72 h PI followed by a 5......-fold increase at 144 h PI. Glutathione reductase and monodehydroascorbate reductase activities were also detected at 4 h PI, and showed modest increases of 1.8- and 2.7-fold, respectively, by 144 h PI. The combination of functional analysis with the proteomics approach enabled correlation...

Final report of the safety assessment of L-Ascorbic Acid, Calcium Ascorbate, Magnesium Ascorbate, Magnesium Ascorbyl Phosphate, Sodium Ascorbate, and Sodium Ascorbyl Phosphate as used in cosmetics.

Science.gov (United States)

Elmore, Amy R

2005-01-01

L-Ascorbic Acid, Calcium Ascorbate, Magnesium Ascorbate, Magnesium Ascorbyl Phosphate, Sodium Ascorbate, and Sodium Ascorbyl Phosphate function in cosmetic formulations primarily as antioxidants. Ascorbic Acid is commonly called Vitamin C. Ascorbic Acid is used as an antioxidant and pH adjuster in a large variety of cosmetic formulations, over 3/4 of which were hair dyes and colors at concentrations between 0.3% and 0.6%. For other uses, the reported concentrations were either very low (cosmetics, but are not currently used. Sodium Ascorbyl Phosphate functions as an antioxidant in cosmetic products and is used at concentrations ranging from 0.01% to 3%. Magnesium Ascorbyl Phosphate functions as an antioxidant in cosmetics and was reported being used at concentrations from 0.001% to 3%. Sodium Ascorbate also functions as an antioxidant in cosmetics at concentrations from 0.0003% to 0.3%. Related ingredients (Ascorbyl Palmitate, Ascorbyl Dipalmitate, Ascorbyl Stearate, Erythorbic Acid, and Sodium Erythorbate) have been previously reviewed by the Cosmetic Ingredient Review (CIR) Expert Panel and found "to be safe for use as cosmetic ingredients in the present practices of good use." Ascorbic Acid is a generally recognized as safe (GRAS) substance for use as a chemical preservative in foods and as a nutrient and/or dietary supplement. Calcium Ascorbate and Sodium Ascorbate are listed as GRAS substances for use as chemical preservatives. L-Ascorbic Acid is readily and reversibly oxidized to L-dehydroascorbic acid and both forms exist in equilibrium in the body. Permeation rates of Ascorbic Acid through whole and stripped mouse skin were 3.43 +/- 0.74 microg/cm(2)/h and 33.2 +/- 5.2 microg/cm(2)/h. Acute oral and parenteral studies in mice, rats, rabbits, guinea pigs, dogs, and cats demonstrated little toxicity. Ascorbic Acid and Sodium Ascorbate acted as a nitrosation inhibitor in several food and cosmetic product studies. No compound-related clinical signs or gross or

Silenced rice in both cytosolic ascorbate peroxidases displays pre-acclimation to cope with oxidative stress induced by 3-aminotriazole-inhibited catalase.

Science.gov (United States)

Bonifacio, Aurenivia; Carvalho, Fabrício E L; Martins, Marcio O; Lima Neto, Milton C; Cunha, Juliana R; Ribeiro, Carolina W; Margis-Pinheiro, Marcia; Silveira, Joaquim A G

2016-08-20

The maintenance of H2O2 homeostasis and signaling mechanisms in plant subcellular compartments is greatly dependent on cytosolic ascorbate peroxidases (APX1 and APX2) and peroxisomal catalase (CAT) activities. APX1/2 knockdown plants were utilized in this study to clarify the role of increased cytosolic H2O2 levels as a signal to trigger the antioxidant defense system against oxidative stress generated in peroxisomes after 3-aminotriazole-inhibited catalase (CAT). Before supplying 3-AT, silenced APX1/2 plants showed marked changes in their oxidative and antioxidant profiles in comparison to NT plants. After supplying 3-AT, APX1/2 plants triggered up-expression of genes belonging to APX (OsAPX7 and OsAPX8) and GPX families (OsGPX1, OsGPX2, OsGPX3 and OsGPX5), but to a lower extent than in NT plants. In addition, APX1/2 exhibited lower glycolate oxidase (GO) activity, higher CO2 assimilation, higher cellular integrity and higher oxidation of GSH, whereas the H2O2 and lipid peroxidation levels remained unchanged. This evidence indicates that redox pre-acclimation displayed by silenced rice contributed to coping with oxidative stress generated by 3-AT. We suggest that APX1/2 plants were able to trigger alternative oxidative and antioxidant mechanisms involving signaling by H2O2, allowing these plants to display effective physiological responses for protection against oxidative damage generated by 3-AT, compared to non-transformed plants. Copyright © 2016 Elsevier GmbH. All rights reserved.

The water-water cycle as alternative photon and electron sinks.

OpenAIRE

Asada, K

2000-01-01

The water-water cycle in chloroplasts is the photoreduction of dioxygen to water in photosystem I (PS I) by the electrons generated in photosystem II (PS II) from water. In the water-water cycle, the rate of photoreduction of dioxygen in PS I is several orders of magnitude lower than those of the disproportionation of superoxide catalysed by superoxide dismutase, the reduction of hydrogen peroxide to water catalysed by ascorbate peroxidase, and the reduction of the resulting oxidized forms of...

Signal function of cytokinin 6-benzylaminopurine in the reaction of Triticum aestivum L. mesophyll cells to hyperthermia

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M. M. Musienko

2014-12-01

Full Text Available The signaling effect of 6-benzylaminopurine (BAP on leaf mesophyll cells of Triticum aestivum L. under hyperthermic conditions was studied­. It was found that BAP regulated photosynthetic pigment, hydrogen peroxide content and activity of antioxidant enzymes, namely superoxide dismutase, ascorbate peroxidase and catalase under high-temperature conditions. The additive effect of BAP and high temperature on the activation of cell antioxidant systems was demonstrated. BAP regulated reducing processes in mesophyll leaf cells under high-temperature conditions.

Arabidopsis CDS blastp result: AK108458 [KOME

Lifescience Database Archive (English)

Full Text Available AK108458 002-143-D05 At4g35000.1 L-ascorbate peroxidase 3 (APX3) identical to ascorbat...e peroxidase 3 [Arabidopsis thaliana] GI:2444019, L-ascorbate peroxidase [Arabidopsis thaliana] gi|152379...1|emb|CAA66926; similar to ascorbate peroxidase [Gossypium hirsutum] gi|1019946|gb|AAB52954 2e-35 ...

Arabidopsis CDS blastp result: AK070842 [KOME

Lifescience Database Archive (English)

Full Text Available AK070842 J023074O14 At4g35000.1 L-ascorbate peroxidase 3 (APX3) identical to ascorbat...e peroxidase 3 [Arabidopsis thaliana] GI:2444019, L-ascorbate peroxidase [Arabidopsis thaliana] gi|1523791...|emb|CAA66926; similar to ascorbate peroxidase [Gossypium hirsutum] gi|1019946|gb|AAB52954 1e-112 ...

Oxidation of the tryptophan 32 residue of human superoxide dismutase 1 caused by its bicarbonate-dependent peroxidase activity triggers the non-amyloid aggregation of the enzyme.

Science.gov (United States)

Coelho, Fernando R; Iqbal, Asif; Linares, Edlaine; Silva, Daniel F; Lima, Filipe S; Cuccovia, Iolanda M; Augusto, Ohara

2014-10-31

The role of oxidative post-translational modifications of human superoxide dismutase 1 (hSOD1) in the amyotrophic lateral sclerosis (ALS) pathology is an attractive hypothesis to explore based on several lines of evidence. Among them, the remarkable stability of hSOD1(WT) and several of its ALS-associated mutants suggests that hSOD1 oxidation may precede its conversion to the unfolded and aggregated forms found in ALS patients. The bicarbonate-dependent peroxidase activity of hSOD1 causes oxidation of its own solvent-exposed Trp(32) residue. The resulting products are apparently different from those produced in the absence of bicarbonate and are most likely specific for simian SOD1s, which contain the Trp(32) residue. The aims of this work were to examine whether the bicarbonate-dependent peroxidase activity of hSOD1 (hSOD1(WT) and hSOD1(G93A) mutant) triggers aggregation of the enzyme and to comprehend the role of the Trp(32) residue in the process. The results showed that Trp(32) residues of both enzymes are oxidized to a similar extent to hSOD1-derived tryptophanyl radicals. These radicals decayed to hSOD1-N-formylkynurenine and hSOD1-kynurenine or to a hSOD1 covalent dimer cross-linked by a ditryptophan bond, causing hSOD1 unfolding, oligomerization, and non-amyloid aggregation. The latter process was inhibited by tempol, which recombines with the hSOD1-derived tryptophanyl radical, and did not occur in the absence of bicarbonate or with enzymes that lack the Trp(32) residue (bovine SOD1 and hSOD1(W32F) mutant). The results support a role for the oxidation products of the hSOD1-Trp(32) residue, particularly the covalent dimer, in triggering the non-amyloid aggregation of hSOD1. © 2014 by The American Society for Biochemistry and Molecular Biology, Inc.

Plant growth regulators and ascorbic acid effects on physiological quality of wheat seedlings obtained from deteriorated seeds

International Nuclear Information System (INIS)

Moori, S.; Eisv, H.R.

2017-01-01

This study attempted to examine the effect of seed priming using plant growth regulators and vitamin C on the physiological traits of non-aged and aged seeds of wheat and their obtained seedlings. Accelerated aging (AA) method (40 degree C, RH=100% for 72h) was used for aging seeds. The seeds were pre-treated by gibberellin (GA), salicylic acid (SA), brassinosteroid (BR), and ascorbic acid (AS). Some seed traits such as germination and electric conductivity (EC) and seedling traits such as malondialdehyde (MDA) content, activity of some antioxidant enzymes, soluble protein content (SP), soluble sugar (SS), and proline were measured seven days after germination. The results showed that accelerated aging of seeds reduces the germination percentage and speed, increases soluble sugar, and reduces soluble protein, activity of catalase (CAT), peroxidase (POD) and superoxide dismutase (SOD) in the seedling. Pre-treatment of the aged seed by GA had the maximum positive impact on seed germination and seedling growth. Priming improved germination indices, quality of seedling, and seedling resistance against the oxidative stress caused by AA. It also improved cell membrane integrity and thus reduced seeds’ EC. Priming increased the activity of CAT, POD and SOD enzymes in both aged and non-aged seeds. When the deteriorated seeds were primed, proline and SS contents of the seedling increased significantly, but SP and MDA decreased. In general, pre-treatment of the non-aged and aged seeds by gibberellin improved the physiological quality of the seed and seedling. (author)

Selenium alleviates cadmium toxicity by preventing oxidative stress in sunflower (Helianthus annuus) seedlings.

Science.gov (United States)

Saidi, Issam; Chtourou, Yacine; Djebali, Wahbi

2014-03-01

The present study investigated the possible mediatory role of selenium (Se) in protecting plants from cadmium (Cd) toxicity. The exposure of sunflower seedlings to 20μM Cd inhibited biomass production, decreased chlorophyll and carotenoid concentrations and strongly increased accumulation of Cd in both roots and shoots. Similarly, Cd enhanced hydrogen peroxides content and lipid peroxidation as indicated by malondialdehyde accumulation. Pre-soaking seeds with Se (5, 10 and 20μM) alleviated the negative effect of Cd on growth and led to a decrease in oxidative injuries caused by Cd. Furthermore, Se enhanced the activities of catalase, ascorbate peroxidase and glutathione reductase, but lowered that of superoxide dismutase and guaiacol peroxidase. As important antioxidants, ascorbate and glutathione contents in sunflower leaves exposed to Cd were significantly decreased by Se treatment. The data suggest that the beneficial effect of Se during an earlier growth period could be related to avoidance of cumulative damage upon exposure to Cd, thus reducing the negative consequences of oxidative stress caused by heavy metal toxicity. Copyright © 2013 Elsevier GmbH. All rights reserved.

Effects of Polysaccharide-Based Edible Coatings on Quality and Antioxidant Enzyme System of Strawberry during Cold Storage

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Li Li

2017-01-01

Full Text Available Strawberry is a nutritious, but highly perishable fruit. Three polysaccharide-based edible coatings (alginate, chitosan, and pullulan were applied to postharvest strawberry fruit during cold storage (4°C, and their effects on fruit quality and antioxidant enzyme system were investigated in the present study. The results showed that polysaccharide coatings showed a significant delay in fruit softening and rot and reduced changes in total soluble solid and titratable acidity content during 16 d storage. Polysaccharide coatings also maintained higher ascorbic acid and total phenolic contents than control from day 2 and significantly inhibited fruit decay and respiration after 12 d storage (p<0.05. Polysaccharide treatments enhanced the activities of antioxidant enzymes (peroxidase, catalase, superoxide dismutase, and ascorbate peroxidase so as to prevent lipid peroxidation and reduce membrane damage. Additionally, chitosan coating had the most positive effects on fruit quality amongst three polysaccharide-based edible coatings and presented the highest relative activities of antioxidant enzymes. These results indicated that polysaccharide-based edible coatings were helpful in postharvest quality maintenance of strawberry fruit.

INCREASING SALT TOLERANCE OF CHICKPEA (CICER ARIETINUM) PLANTS BY INTERACTION EFFECTS OF GAMMA IRRADIATION AND GIBBERELLIC ACID

International Nuclear Information System (INIS)

2007-01-01

The effect of gamma radiation on growth, photosynthetic pigments and some of the antioxidant enzymes of chickpea (Cicer arietinum L.) seeds were investigated. After irradiation with different doses of gamma radiation (20 and 40 Gy), seeds were soaked for 24 hours in either GA 3 , NaCl solution or in a mixture of both. NaCl induced reduction in growth as well as decrease in photosynthetic pigment content of the produced seedlings. However, GA 3 caused amelioration in growth inhibition and an increase in the pigment contents. Irradiated chickpea seeds treated with GA 3 evolved defence antioxidant mechanisms to combat the danger of salt stress by increasing the superoxide dismutase (SOD), ascorbate peroxidase (APX), catalase (CAT) and peroxidase (POX) activities while malonaldehyde (MDA) contents were decreased

Correlation of serum paraoxonase activities in known cases of 130 elderly hypertensive South Asian aged 56-64 years - a hospital based study

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Arun Kumar

2014-02-01

Full Text Available Objective: To evaluate paraoxonase activity, antioxidant status and lipid peroxidation in hypertensive participants and to address the hypothesis that oxidative modifications of lipids due to hypertension can cause changes in serum paraoxonase activities. Methods: The serum paraoxonase activities, antioxidants and lipid peroxidation were determined in 130 hypertensive participants and 130 age-sexes matched normotensive healthy volunteers served as control. Serum paraoxonase activities were measured by enzymatic kit. The glutathione peroxidase, superoxide dismutase and catalase activity were determined by standard methods. Malondialdehyde was measured by thiobarbituric acid reaction. Conjugated diene level was measured by Recknagel and Glende method. Serum uric acid, total bilirubin, serum albumin, serum ascorbic acid and lipid profile were analyzed by standard methods. Results: Total cholesterol, triglycerides, low-density lipoprotein cholesterol were significantly higher and high-density lipoprotein cholesterol were significantly lower in hypertensive patients when compared to normotensive healthy controls. The superoxide dismutase, glutathione peroxidase and catalase were significantly lower in hypertensive when compared with normotensive. Similar findings were observed in the levels of albumin, uric acid, bilirubin and ascorbic acid when hypertensives were compared with normotensive. The oxidative stress indicators namely malondialdehyde and conjugated diene were significantly higher and paraoxonase activity were significantly lower in hypertensive. Conclusions: Our study concludes that paraoxonase activities are bound to alter in hypertension which is caused due to interplay of several confounding factors namely oxidative stress, increased oxidized low-density lipoprotein and depletion of antioxidants.

Ascorbic Acid

Science.gov (United States)

Ascorbic acid is used to prevent and treat scurvy, a disease caused by a lack of vitamin C in ... Ascorbic acid comes in extended-release (long-acting) capsules and tablets, lozenges, syrup, chewable tablets, and liquid drops to ...

Antioxidant modulation in response to heavy metal induced oxidative stress in Cladophora glomerata.

Science.gov (United States)

Murugan, K; Harish, S R

2007-11-01

The present investigation was carried out to study the induction of oxidative stress subjected to heavy metal environment. Lipoperoxides showed positive correlation at heavy metal accumulation sites indicating the tissue damage resulting from the reactive oxygen species and resulted in unbalance to cellular redox status. The high activities of ascorbate peroxidase and superoxide dismutase probably counter balance this oxidative stress. Glutathione and soluble phenols decreased, whereas dehydroascorbate content increased in the algae from polluted sites. The results suggested that alga responded to heavy metals effectively by antioxidant compounds and scavenging enzymes.

Relationship of ascorbic acid metabolism with the cytoplasmic male sterility in pepper (Capsicum annuum L.)

International Nuclear Information System (INIS)

Wen, J.; Deng, M.

2015-01-01

To elucidate the metabolic mechanism of Ascorbic Acid (ASA) in the CMS-pepper anthers, the metabolism changes in the reactive oxygen species (ROS) contents, antioxidants contents and ROS scavenging enzymatic activities were investigated in the anther mitochondria of CMS-9704A and maintainer-9704B. At the abortion stage, anthers of CMS-9704A had higher contents of ROS than those of the maintainer. Simultaneously, there were lower contents of ASA and glutathione (GSH) in stage 2 and 3, and the lower activities of ascorbate peroxidase (APX) and glutathione perodixase (GPX) in stage 3 in scavenging ROS in the anthers of the CMS line than maintainer. The expression level of APX and GPX in stage 3 in anthers of CMS-9704A was obviously inhibited when ROS produced with a great deal during anther stage; however the gene expression kept normal in the maintainer. Excessive accumulation of ROS, significant reduction activities and gene expression level of ROS-scavenging enzyme were coinstantaneous with CMS. (author)

Expression Patterns of Genes Involved in Ascorbate-Glutathione Cycle in Aphid-Infested Maize (Zea mays L.) Seedlings.

Science.gov (United States)

Sytykiewicz, Hubert

2016-02-23

Reduced forms of ascorbate (AsA) and glutathione (GSH) are among the most important non-enzymatic foliar antioxidants in maize (Zea mays L.). The survey was aimed to evaluate impact of bird cherry-oat aphid (Rhopalosiphum padi L.) or grain aphid (Sitobion avenae F.) herbivory on expression of genes related to ascorbate-glutathione (AsA-GSH) cycle in seedlings of six maize varieties (Ambrozja, Nana, Tasty Sweet, Touran, Waza, Złota Karłowa), differing in resistance to the cereal aphids. Relative expression of sixteen maize genes encoding isoenzymes of ascorbate peroxidase (APX1, APX2, APX3, APX4, APX5, APX6, APX7), monodehydroascorbate reductase (MDHAR1, MDHAR2, MDHAR3, MDHAR4), dehydroascorbate reductase (DHAR1, DHAR2, DHAR3) and glutathione reductase (GR1, GR2) was quantified. Furthermore, effect of hemipterans' attack on activity of APX, MDHAR, DHAR and GR enzymes, and the content of reduced and oxidized ascorbate and glutathione in maize plants were assessed. Seedling leaves of more resistant Z. mays varieties responded higher elevations in abundance of target transcripts. In addition, earlier and stronger aphid-triggered changes in activity of APX, MDHAR, DHAR and GR enzymes, and greater modulations in amount of the analyzed antioxidative metabolites were detected in foliar tissues of highly resistant Ambrozja genotype in relation to susceptible Tasty Sweet plants.

Acinetobacter calcoaceticus CSY-P13 Mitigates Stress of Ferulic and p-Hydroxybenzoic Acids in Cucumber by Affecting Antioxidant Enzyme Activity and Soil Bacterial Community

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Fenghui Wu

2018-06-01

Full Text Available Ferulic acid (FA and p-hydroxybenzoic acid (PHBA are main phenolic compounds accumulated in rhizosphere of continuously cropped cucumber, causing stress in plants. Microbial degradation of a mixture of FA and PHBA is not well understood in soil. We isolated a strain CSY-P13 of Acinetobacter calcoaceticus, inoculated it into soil to protect cucumber from FA and PHBA stress, and explored a mechanism underlying the protection. CSY-P13 effectively degraded a mixture of FA and PHBA in culture solution under conditions of 39.37°C, pH 6.97, and 21.59 g L-1 potassium dihydrogen phosphate, giving rise to 4-vinyl guaiacol, vanillin, vanillic acid, and protocatechuic acid. During FA and PHBA degradation, activities of superoxide dismutase (SOD, catalase, ascorbate peroxidase, and dehydroascorbate reductase in CSY-P13 were induced. Inoculated into cucumber-planted soil containing 220 μg g-1 mixture of FA and PHBA, CSY-P13 degraded FA and PHBA in soil, increased plant height, and decreased malonaldehyde, superoxide radical, and hydrogen peroxide levels in leaves. CSY-P13 also enhanced SOD, guaiacol peroxidase, catalase, glutathione peroxidase, ascorbate peroxidase, monodehydroascorbate reductase, dehydroascorbate reductase, and glutathione reductase activities; increased ascorbate and glutathione contents; and elevated transcript levels of copper/zinc SOD, manganese SOD, and catalase in leaves under FA and PHBA. Moreover, CSY-P13 increased phosphatase, catalase, urease, and sucrase activities and changed bacterial richness, diversity, and community composition by high throughput sequencing in cucumber-planted soil supplemented with the mixture of FA and PHBA. So CSY-P13 degrades the mixture of FA and PHBA in soil and mitigates stress from the two phenolic compounds in cucumber by activating antioxidant enzymes, changing soil bacterial community, and inducing soil enzymes.

Alleviation of cadmium toxicity in Lemna minor by exogenous salicylic acid.

Science.gov (United States)

Lu, Qianqian; Zhang, Tingting; Zhang, Wei; Su, Chunlei; Yang, Yaru; Hu, Dan; Xu, Qinsong

2018-01-01

Cadmium (Cd) is a significant environmental pollutant in the aquatic environment. Salicylic acid (SA) is a ubiquitous phenolic compound. The goal of this study was to assess the morphological, physiological and biochemical changes in duckweed (L. minor) upon exposure to 10μM CdCl 2 , 10μM CdCl 2 plus 50μM SA, or 50μM SA for 7 days. Reversing the effects of Cd, SA decreased Cd accumulation in plants, improved accumulation of minerals (Ca, Mg, Fe, B, Mo) absorption, increased endogenous SA concentration, and phenylalanine ammonialyase (PAL) activity. Chlorosis-associated symptoms, the reduction in chlorophyll content, and the overproduction of reactive oxygen species induced by Cd exposure were largely reversed by SA. SA significantly decreased the toxic effects of Cd on the activities of the superoxide dismutase, peroxidase, catalase, ascorbate peroxidase, and glutathione reductase in the fronds of L. minor. Furthermore, SA reversed the detrimental effects of Cd on total ascorbate, glutathione, the ascorbic acid/oxidized dehydroascorbate and glutathione/glutathione disulphide ratios, lipid peroxidation, malondialdehyde concentration, lipoxygenase activity, and the accumulation of proline. SA induced the up-regulation of heat shock proteins (Hsp70) and attenuated the adverse effects of Cd on cell viability. These results suggest that SA confers tolerance to Cd stress in L. minor through different mechanisms. Copyright © 2017 Elsevier Inc. All rights reserved.

Peroxidases in nanostructures

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Ana Maria eCarmona-Ribeiro

2015-09-01

Full Text Available Peroxidases are enzymes catalyzing redox reactions that cleave peroxides. Their active redox centers have heme, cysteine thiols, selenium, manganese and other chemical moieties. Peroxidases and their mimetic systems have several technological and biomedical applications such as environment protection, energy production, bioremediation, sensors and immunoassays design and drug delivery devices. The combination of peroxidases or systems with peroxidase-like activity with nanostructures such as nanoparticles, nanotubes, thin films, liposomes, micelles, nanoflowers, nanorods and others is often an efficient strategy to improve catalytic activity, targeting and reusability.

Growth and antioxidant system under drought stress in Chickpea (Cicer arietinum L. as sustained by salicylic acid

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B.K. Sarma

2011-12-01

Full Text Available Drought is one of the major factors limiting chickpea production in arid and semi arid regions. There is meagre information available regarding genotypic variation for drought tolerance in chickpea genotypes. Present investigation was carried out to find out the influence of salicylic acid (SA on drought tolerance in four chickpea genotypes. Reduction in relative injury was observed in plants treated with SA @1.5 mM as compared to control seedlings. Relationship between relative water content (RWC, membrane permeability (MP, ascorbic acid (AsA, proline, lipid peroxidation (LPO, hydrogen peroxide (H2O2, catalase (CAT, peroxidase (POX, superoxide dismutase (SOD, ascorbate peroxidase (APX was determined in order to find out whether these parameters can be used as selection criteria for drought tolerance in this crop. Results indicate wide variation in tolerance to drought stress amongst chickpea cultivars at both the critical stages i.e. pre- and post-anthesis. On the basis of growth and antioxidant activity better genotypes Tyson and ICC-4958 appear to be adapted to drought stress tolerance. Early drought stress (pre-anthesis drought was found to be more damaging than the late drought stress (post- anthesis drought.

Multigene families encode the major enzymes of antioxidant metabolism in Eucalyptus grandis L

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Felipe Karam Teixeira

2005-01-01

Full Text Available Antioxidant metabolism protects cells from oxidative damage caused by reactive oxygen species (ROS. In plants, several enzymes act jointly to maintain redox homeostasis. Moreover, isoform diversity contributes to the fine tuning necessary for plant responses to both exogenous and endogenous signals influencing antioxidant metabolism. This study aimed to provide a comprehensive view of the major classes of antioxidant enzymes in the woody species Eucalyptus grandis. A careful survey of the FORESTs data bank revealed 36 clusters as encoding antioxidant enzymes: six clusters encoding ascorbate peroxidase (APx isozymes, three catalase (CAT proteins, three dehydroascorbate reductase (DHAR, two glutathione reductase (GR isozymes, four monodehydroascorbate reductase (MDHAR, six phospholipid hydroperoxide glutathione peroxidases (PhGPx, and 12 encoding superoxide dismutases (SOD isozymes. Phylogenetic analysis demonstrated that all clusters (identified herein grouped with previously characterized antioxidant enzymes, corroborating the analysis performed. With respect to enzymes involved in the ascorbate-glutathione cycle, both cytosolic and chloroplastic isoforms were putatively identified. These sequences were widely distributed among the different ESTs libraries indicating a broad gene expression pattern. Overall, the data indicate the importance of antioxidant metabolism in eucalyptus.

The ascorbate peroxidase APX1 is a direct target of a zinc finger transcription factor ZFP36 and a late embryogenesis abundant protein OsLEA5 interacts with ZFP36 to co-regulate OsAPX1 in seed germination in rice.

Science.gov (United States)

Huang, Liping; Jia, Jing; Zhao, Xixi; Zhang, MengYao; Huang, Xingxiu; E Ji; Ni, Lan; Jiang, Mingyi

2018-01-01

Seed germination is a vital developmental process. Abscisic acid (ABA) is an essential repressor of seed germination, while ROS (reactive oxygen species) also plays a vital role in regulating seed germination. ABA could inhibit the production of ROS in seed germination, but the mechanism of ABA reduced ROS production in seed germination was hitherto unknown. Here, by ChIP (chromatin immunoprecipitation)-seq, we found that ZFP36, a rice zinc finger transcription factor, could directly bind to the promoter of OsAPX1, coding an ascorbate peroxidase (APX) which has the most affinity for H 2 O 2 (substrate; a type of ROS), and act as a transcriptional activator of OsAPX1 promoter. Moreover, ZFP36 could interact with a late embryogenesis abundant protein OsLEA5 to co-regulate the promoter activity of OsAPX1. The seed germination is highly inhibited in ZFP36 overexpression plants under ABA treatment, while an RNA interference (RNAi) mutant of OsLEA5 rice seeds were less sensitive to ABA, and exogenous ASC (ascorbate acid) could alleviate the inhibition induced by ABA. Thus, our conclusion is that OsAPX1 is a direct target of ZFP36 and OsLEA5 could interact with ZFP36 to co-regulate ABA-inhibited seed germination by controlling the expression of OsAPX1. Copyright © 2017. Published by Elsevier Inc.

Effects of administration of beta-carotene, ascorbic acid, persimmons, and pods on antioxidative ability in UV-irradiated ODS rats.

Science.gov (United States)

Hosotani, Keisuke; Yoshida, Minoru; Kitagawa, Masahiro

2005-07-01

To evaluate the effects of supplementing diets with carotenoid and ascorbic acid (AsA) on the antioxidative ability of Osteogenic Disorder-Shionogi (ODS) rats, we added synthetic beta-carotene (betaC), AsA, and powders of persimmon (Ka) and pods (Po) containing betaC and AsA to the diet and obtained the following results. The urinary 8-hydroxydeoxyguanosine (8-OHdG) concentration was low in the -betaC.AsA and +AsA groups but high in the +betaC.AsA, +Ka, and +Po groups. The thiobarbituric acid-reactive substances (TBARS) in both the liver and skin were higher in the -betaC.AsA group than in the +betaC.AsA group and were low in the +Ka and +Po groups. As antioxidant enzymes, glutathione peroxidase (GSH-Px) activity was high in the +betaC.AsA group, low in the -beta3C.AsA group in both the skin and liver, and also high in the + Ka and +Po group in the liver. Superoxide dismutase (SOD) activity was high in the -betaC.AsA group and low in the +betaC.AsA and +Ka groups in both the skin and liver. Catalase (CAT) activity in the liver was low in the -betaC.AsA, +AsA, and +betaC groups and high in the +betaC.AsA and +Po groups. These results confirmed that the administration of betaC, AsA, and persimmons and pods increases antioxidative ability in the skin and liver of ultraviolet-b(UV-B)-irradiated ODS rats.

Genotype-Dependent Effect of Exogenous Nitric Oxide on Cd-induced Changes in Antioxidative Metabolism, Ultrastructure, and Photosynthetic Performance in Barley Seedlings (Hordeum vulgare)

DEFF Research Database (Denmark)

Chen, Fei; Wang, Fang; Sun, Hongyan

2010-01-01

M Cd increased the accumulation of O2•-, H2O2, and malondialdehyde (MDA) but reduced plant height, chlorophyll content, net photosynthetic rate (P n), and biomass, with a much more severe response in the Cd-sensitive genotype. Antioxidant enzyme activities increased significantly under Cd stress......A greenhouse hydroponic experiment was performed using Cd-sensitive (cv. Dong 17) and Cd-tolerant (Weisuobuzhi) barley seedlings to evaluate how different genotypes responded to cadmium (Cd) toxicity in the presence of sodium nitroprusside (SNP), a nitric oxide (NO) donor. Results showed that 5 μ...... in the roots of the tolerant genotype, whereas in leaves of the sensitive genotype, superoxide dismutase (SOD) and ascorbate peroxide (APX), especially cytosol ascorbate peroxidase (cAPX), decreased after 5-15 days Cd exposure. Moreover, Cd induces NO synthesis by stimulating nitrate reductase and nitric oxide...

Infestation of potato (Solanum tuberosum L.) by the peach-potato aphid (Myzus persicae Sulzer) alters cellular redox status and is influenced by ascorbate.

Science.gov (United States)

Kerchev, Pavel I; Fenton, Brian; Foyer, Christine H; Hancock, Robert D

2012-02-01

The peach-potato aphid (Myzus persicae Sulzer) is a major pest of potato (Solanum tuberosum L.) but the molecular characterization of this interaction particularly with regard to oxidants and antioxidants remains to be undertaken. Aphid colonies reared on potato leaves containing high ascorbate were twice the size of those grown on leaves with low ascorbate. Infestation-dependent decreases in the abundance of key transcripts such as chloroplastic FeSOD, peroxisomal catalase 2, PR1 and JAZ1 preceded detectable leaf H(2)O(2) or polyphenol accumulation. The leaf glutathione pool was increased 48 h after infestation, but the amount of ascorbate was unchanged. The ascorbate/dehydroacorbate (DHA) ratio was lower at 48 h but the ratio of reduced glutathione (GSH) to oxidized glutathione (GSSG) was unchanged. While DHA reductase and GSSG reductase activities were unaffected by aphid feeding, non-specific peroxidase activities were enhanced 48 h following aphid infestation. Brown ethanol-insoluble deposits were observed close to leaf veins following aphid infestation. Taken together, the results demonstrate that high ascorbate favours aphid colony expansion and that perturbations in the leaf antioxidant system are intrinsic to the potato leaf response to aphids. Moreover, these changes together with the induction of hormone-related transcripts precede the deposition of defence-associated oxidized polyphenols along the stylet track. © 2011 Blackwell Publishing Ltd.

Sodium orthovanadate associated with pharmacological doses of ascorbate causes an increased generation of ROS in tumor cells that inhibits proliferation and triggers apoptosis

Energy Technology Data Exchange (ETDEWEB)

Günther, T-hat nia Mara Fischer; Kviecinski, Maicon Roberto; Baron, Carla Cristine; Felipe, Karina Bettega; Farias, Mirelle Sifroni; Ourique da Silva, Fabiana; Bücker, Nádia Cristina Falcão [Departamento de Bioquímica, Universidade Federal de Santa Catarina, Florianópolis (Brazil); Pich, Claus Tröger [Campus de Araranguá, Universidade Federal de Santa Catarina, Araranguá (Brazil); Ferreira, Eduardo Antonio [Universidade de Brasília, Faculdade de Ceilândia, DF (Brazil); Filho, Danilo Wilhelm [Departamento de Ecologia e Zoologia, Universidade Federal de Santa Catarina, Florianópolis (Brazil); Verrax, Julien; Calderon, Pedro Buc [Toxicology and Cancer Biology Research Group, Louvain Drug Research Institute, Université Catholique de Louvain, Brussels (Belgium); Pedrosa, Rozangela Curi, E-mail: rozangelapedrosa@gmail.com [Departamento de Bioquímica, Universidade Federal de Santa Catarina, Florianópolis (Brazil)

2013-01-18

Graphical abstract: -- Abstract: Pharmacological doses of ascorbate were evaluated for its ability to potentiate the toxicity of sodium orthovanadate (Na{sub 3}VO{sub 4}) in tumor cells. Cytotoxicity, inhibition of cell proliferation, generation of ROS and DNA fragmentation were assessed in T24 cells. Na{sub 3}VO{sub 4} was cytotoxic against T24 cells (EC{sub 50} = 5.8 μM at 24 h), but in the presence of ascorbate (100 μM) the EC{sub 50} fell to 3.3 μM. Na{sub 3}VO{sub 4} plus ascorbate caused a strong inhibition of cell proliferation (up to 20%) and increased the generation of ROS (4-fold). Na{sub 3}VO{sub 4} did not directly cleave plasmid DNA, at this aspect no synergism was found occurring between Na{sub 3}VO{sub 4} and ascorbate once the resulting action of the combination was no greater than that of both substances administered separately. Cells from Ehrlich ascites carcinoma-bearing mice were used to determine the activity of antioxidant enzymes, the extent of the oxidative damage and the type of cell death. Na{sub 3}VO{sub 4} alone, or combined with ascorbate, increased catalase activity, but only Na{sub 3}VO{sub 4} plus ascorbate increased superoxide dismutase activity (up to 4-fold). Oxidative damage on proteins and lipids was higher due to the treatment done with Na{sub 3}VO{sub 4} plus ascorbate (2–3-fold). Ascorbate potentiated apoptosis in tumor cells from mice treated with Na{sub 3}VO{sub 4}. The results indicate that pharmacological doses of ascorbate enhance the generation of ROS induced by Na{sub 3}VO{sub 4} in tumor cells causing inhibition of proliferation and apoptosis. Apoptosis induced by orthovanadate and ascorbate is closer related to inhibition on Bcl-xL and activation of Bax. Our data apparently rule out a mechanism of cell demise p53-dependent or related to Cdk2 impairment.

Growth and physiological responses to cadmium stress of two populations of Dittrichia viscosa (L.) Greuter

Energy Technology Data Exchange (ETDEWEB)

Fernández, R.; Bertrand, A. [Departamento de Biología de Organismos y Sistemas, Universidad de Oviedo, Catedrático Rodrigo Uría s/n, 33071 Oviedo (Spain); Instituto Universitario de Biotecnología de Asturias (Spain); Reis, R.; Mourato, M.P.; Martins, L.L. [Departamento de Química Agrícola e Ambiental, Universidade Técnica de Lisboa, Tapada da Ajuda 1349-017, Lisboa (Portugal); González, A., E-mail: aidag@uniovi.es [Departamento de Biología de Organismos y Sistemas, Universidad de Oviedo, Catedrático Rodrigo Uría s/n, 33071 Oviedo (Spain); Instituto Universitario de Biotecnología de Asturias (Spain)

2013-01-15

Highlights: ► Cd tolerance and accumulation are constitutive traits in D. viscosa. ► The physiological mechanisms involved in Cd stress differed between clones. ► The metallicolous clone was more Cd tolerant than the non-metallicolous one. ► Antioxidant enzymes had important roles in each clone, especially peroxidases. -- Abstract: Two clones of Dittrichia viscosa (L.) Greuter from contrasting populations, DV-A (metallicolous) and DV-W (non-metallicolous), were studied to compare Cd accumulation and tolerance. After 10 days of hydroponic culture with 0, 5, 10, and 15 mg Cd L{sup −1}, metal accumulation and plant growth were measured as well as other stress markers such as decrease in the content of photosynthetic pigments, lipid peroxidation, phenols, H{sub 2}O{sub 2}, and free proline. We also analyzed the activity of the antioxidant enzymes guaiacol and ascorbate peroxidases, catalase, superoxide dismutase, and glutathione reductase as well as their isoform patterns. Our results confirmed a high Cd tolerance and accumulation in both clones of D. viscosa, which suggests that these traits are constitutive in this species. However, when the Cd concentration in solution exceeded 10 mg Cd L{sup −1}, DV-A was more tolerant than DV-W. The physiological mechanisms involved in Cd tolerance also differed between them, although phenols and guaiacol peroxidase played an important role in both clones. The effective Cd detoxification of DV-A consisted mainly in a promoted ascorbate peroxidase activity and better efficiency of catalase and glutathione reductase enzymes.

Role of ascorbic acid in the inhibition of polyphenol oxidase and the prevention of browning in different browning-sensitive Lactuca sativa var. capitata (L.) and Eruca sativa (Mill.) stored as fresh-cut produce.

Science.gov (United States)

Landi, Marco; Degl'Innocenti, Elena; Guglielminetti, Lorenzo; Guidi, Lucia

2013-06-01

Polyphenol oxidase (PPO) and, to a minor extent, peroxidase (POD) represent the key enzymes involved in enzymatic browning, a negative process induced by cutting fresh-cut produce such as lettuce (Lactuca sativa) and rocket salad (Eruca sativa). Although ascorbic acid is frequently utilised as an anti-browning agent, its mechanism in the prevention of the browning phenomenon is not clearly understood. The activity of PPO and POD and their isoforms in lettuce (a high-browning and low-ascorbic acid species) and rocket salad (a low-browning and high-ascorbic species) was characterised. The kinetic parameters of PPO and in vitro ascorbic acid-PPO inhibition were also investigated. In rocket salad, PPO activity was much lower than that in lettuce and cutting induced an increase in PPO activity only in lettuce. Exogenous ascorbic acid (5 mmol L(-1)) reduced PPO activity by about 90% in lettuce. POD did not appear to be closely related to browning in lettuce. PPO is the main enzyme involved in the browning phenomenon; POD appears to play a minor role. The concentration of endogenous ascorbic acid in rocket salad was related to its low-browning sensitivity after cutting. In lettuce, the addition of ascorbic acid directly inhibited PPO activity. The results suggest that the high ascorbic acid content found in rocket salad plays an effective role in reducing PPO activity. © 2012 Society of Chemical Industry.

Characterization of antioxidant enzymes and peroxisomes of olive (Olea europaea L.) fruits.

Science.gov (United States)

Lopez-Huertas, Eduardo; del Río, Luis A

2014-10-15

The presence of peroxisomes in olive (Olea europaea L.) fruits and different antioxidant enzymes occurring in this plant tissue is reported for the first time. Ultrastructural analysis showed that olive cells were characterized by the presence of large vacuoles and lipid drops. Plastids, mitochondria and peroxisomes were placed near the cell wall, showing some type of association with it. Olive fruit peroxisomes were purified by sucrose density-gradient centrifugation, and catalase, glutathione reductase and ascorbate peroxidase were found in peroxisomes. In olive fruit tissue the presence of a battery of antioxidant enzymes was demonstrated, including catalase, four superoxide dismutase isozymes (mainly an Fe-SOD plus 2 Cu,Zn-SOD and a Mn-SOD), all the enzymes of the ascorbate-glutathione cycle, reduced and oxidized glutathione, ascorbate, and four NADPH-recycling dehydrogenases. The knowledge of the full composition of antioxidants (enzymatic and non-enzymatic) in olive fruits is crucial to be able to understand the processes regulating the antioxidant composition of olive oil. Copyright © 2014 Elsevier GmbH. All rights reserved.

H2O2 mediates ALA-induced glutathione and ascorbate accumulation in the perception and resistance to oxidative stress in Solanum lycopersicum at low temperatures.

Science.gov (United States)

Liu, Tao; Hu, Xiaohui; Zhang, Jiao; Zhang, Junheng; Du, Qingjie; Li, Jianming

2018-02-15

Low temperature is a crucial factor influencing plant growth and development. The chlorophyll precursor, 5-aminolevulinic acid (ALA) is widely used to improve plant cold tolerance. However, the interaction between H 2 O 2 and cellular redox signaling involved in ALA-induced resistance to low temperature stress in plants remains largely unknown. Here, the roles of ALA in perceiving and regulating low temperature-induced oxidative stress in tomato plants, together with the roles of H 2 O 2 and cellular redox states, were characterized. Low concentrations (10-25 mg·L - 1 ) of ALA enhanced low temperature-induced oxidative stress tolerance of tomato seedlings. The most effective concentration was 25 mg·L - 1 , which markedly increased the ratio of reduced glutathione and ascorbate (GSH and AsA), and enhanced the activities of superoxide dismutase, catalase, ascorbate peroxidase, dehydroascorbate reductase, and glutathione reductase. Furthermore, gene expression of respiratory burst oxidase homolog1 and H 2 O 2 content were upregulated with ALA treatment under normal conditions. Treatment with exogenous H 2 O 2 , GSH, and AsA also induced plant tolerance to oxidative stress at low temperatures, while inhibition of GSH and AsA syntheses significantly decreased H 2 O 2 -induced oxidative stress tolerance. Meanwhile, scavenging or inhibition of H 2 O 2 production weakened, but did not eliminate, GSH- or AsA- induced tomato plant tolerance to oxidative stress at low temperatures. Appropriate concentrations of ALA alleviated the low temperature-induced oxidative stress in tomato plants via an antioxidant system. The most effective concentration was 25 mg·L - 1 . The results showed that H 2 O 2 induced by exogenous ALA under normal conditions is crucial and may be the initial step for perception and signaling transmission, which then improves the ratio of GSH and AsA. GSH and AsA may then interact with H 2 O 2 signaling, resulting in enhanced antioxidant capacity

Fate of the synergistic antioxidant system ascorbic acid, lecithin, and tocopherol in mayonnaise: Partion of ascorbic acid

DEFF Research Database (Denmark)

Meyer, Anne Merete Boye; Jacobsen, Charlotte Munch

1996-01-01

Meyer, A. S. & C. Jacobsen, 1996. Fate of the synergistic antioxidant system ascorbic acid, lecithin, and tocopherol in mayonnaise: Partion of ascorbic acid, J. Food Lipids, 3, 139-147.......Meyer, A. S. & C. Jacobsen, 1996. Fate of the synergistic antioxidant system ascorbic acid, lecithin, and tocopherol in mayonnaise: Partion of ascorbic acid, J. Food Lipids, 3, 139-147....

Analysis of manganese superoxide dismutase (MnSOD: Ala-9Val and glutathione peroxidase (GSH-Px: Pro 197 Leu gene polymorphisms in mood disorders.

Directory of Open Access Journals (Sweden)

Birgül Elbozan Cumurcu

2013-05-01

Full Text Available We investigated the etiopathogenetic role of manganese superoxide dismutase (MnSOD (Ala-9Val and glutathione peroxidase (GSH-Px (Pro 197 Leu gene polymorphisms in patients diagnosed with major depressive disorder (MDD and bipolar I disorder (BD. Eighty patients with MDD, 82 patients with BD (total 162 patients and 96 healthy controls were enrolled in this study and genotyped using a Real Time-Quantitative Polymer Chain Reaction (RT-qPCR-based method. The patients with BD and MDD and the controls had a similar distribution of the genotypes and alleles in the Ala-9Val MnSOD gene polymorphism. Comparison of the MDD group and control group regarding the Pro197 Leu GSH-Px gene polymorphism revealed similar genotype distribution but different allele distribution. The BD group and control group were similar both for genotypes and for alleles when compared regarding the Pro 197 Leu GSH-Px gene polymorphism. The combined analysis (MDD plus BD also failed to find any association between the Ala-9Val MnSOD and Pro 197 Leu GSH-Px gene polymorphism. Although small statistical power of the current study the significant difference between patients with depression and the control group for the Pro 197 Leu GSH-Px polymorphism indicates that the distribution of these alleles may have a contribution in the physiopathogenesis of depression. One of the limitation of the current study is that the sample size is too small. Understanding of the exact role of Pro 197 LeuGSH-Px polymorphism in the development of depression needs to further studies with more sample size and high statistical power.

Understanding the degradation of ascorbic acid and glutathione in relation to the levels of oxidative stress biomarkers in broccoli (Brassica oleracea L. italica cv. Bellstar) during storage and mechanical processing.

Science.gov (United States)

Raseetha, Siva; Leong, Sze Ying; Burritt, David John; Oey, Indrawati

2013-06-01

The purpose of this research was to understand the degradation of ascorbic acid and glutathione content in broccoli florets (Brassica oleracea L. italica cv. Bellstar) during prolonged storage and subsequent mechanical processing. The initial content of total ascorbic acid and glutathione in broccoli florets averaged at 5.18 ± 0.23 and 0.70 ± 0.03 μmol/g fresh weight, respectively. Results showed that the content of ascorbic acid and glutathione in broccoli degraded during storage at 23°C, for at least 4.5-fold after 6 days of storage. On each day of storage, broccoli florets were mechanically processed, but the content of total ascorbic acid and glutathione was not significantly affected. When the mechanically processed broccoli florets were further incubated for up to 6h, the amount of ascorbic acid was greatly reduced as compared to glutathione. To obtain an in-depth understanding on the degradation of ascorbic acid and glutathione, the activity of enzymes involved in plant antioxidative system via ascorbate-glutathione cycle, as a response towards oxidative stress that took place during storage was determined in this study. The content of total ascorbic acid and glutathione in broccoli florets before and after mechanical processing were found to decrease concurrently with the activity of ascorbic acid peroxidase and glutathione reductase over the experimental storage duration. Meanwhile, the effect of oxidative stress on the content of ascorbic acid and glutathione was apparent during the 6h of incubation after mechanical processing. This phenomenon was demonstrated by the level of oxidative stress biomarkers examined, in which the formation of lipid peroxides, protein carbonyls and DNA oxidised products was positively associated with the degradation of total ascorbic acid and glutathione. Copyright © 2012 Elsevier Ltd. All rights reserved.

Arabidopsis thaliana peroxidase N

DEFF Research Database (Denmark)

Mirza, Osman Asghar; Henriksen, A; Ostergaard, L

2000-01-01

The structure of the neutral peroxidase from Arabidopsis thaliana (ATP N) has been determined to a resolution of 1.9 A and a free R value of 20.5%. ATP N has the expected characteristic fold of the class III peroxidases, with a C(alpha) r.m.s.d. of 0.82 A when compared with horseradish peroxidase C...

The imprints of the high light and UV-B stresses in Oryza sativa L. 'Kanchana' seedlings are differentially modulated.

Science.gov (United States)

Faseela, Parammal; Puthur, Jos T

2018-01-01

High light and ultraviolet-B radiation (UV-B) are generally considered to have negative impact on photosynthesis and plant growth. The present study evaluates the tolerance potential of three cultivars of Oryza sativa L. (Kanchana, Mattatriveni and Harsha) seedlings towards high light and UV-B stress on the basis of photosynthetic pigment degradation, chlorophyll a fluorescence parameters and rate of lipid peroxidation, expressed by malondialdehyde content. Surprisingly, it was revealed that Kanchana was the most sensitive cultivar towards high light and at the same time it was the most tolerant cultivar towards UV-B stress. This contrasting feature of Kanchana towards high light and UV-B tolerance was further studied by analyzing photosystem (PS) I and II activity, mitochondrial activity, chlorophyll a fluorescence transient, enzymatic and non-enzymatic antioxidant defense system. Due to the occurrence of more PS I and PSII damages, the inhibition of photochemical efficiency and emission of dissipated energy as heat or fluorescence per PSII reaction center was higher upon high light exposure than UV-B treatments in rice seedlings of Kanchana. The mitochondrial activity was also found to be drastically altered upon high light as compared to UV-B treatments. The UV-B induced accumulation of non-enzymatic antioxidants (proline, total phenolics, sugar and ascorbate) and enzymatic antioxidants (ascorbate peroxidase, guaiacol peroxidase, superoxide dismutase and glutathione reductase) in rice seedlings than those subjected to high light exposure afforded more efficient protection against UV-B radiation in rice seedlings. Our results proved that high tolerance of Kanchana towards UV-B than high light treatments, correlated linearly with the protected photosynthetic and mitochondrial machinery which was provided by upregulation of antioxidants particularly by total phenolics, ascorbate and ascorbate peroxidase in rice seedlings. Data presented in this study conclusively

Ascorbic acid, garlic extract and taurine alleviate cadmium-induced oxidative stress in freshwater catfish (Clarias batrachus)

Energy Technology Data Exchange (ETDEWEB)

Kumar, Puneet, E-mail: puneetbiochem@gmail.com [Aquatic Biotechnology and Fish Pathology Laboratory, Department of Animal Science, M.J.P. Rohilkhand University, Bareilly-243 006 (India); Prasad, Y. [Aquatic Biotechnology and Fish Pathology Laboratory, Department of Animal Science, M.J.P. Rohilkhand University, Bareilly-243 006 (India); Patra, A.K. [West Bengal University of Animal and Fishery Sciences, Kolkata-700037 (India); Ranjan, R.; Swarup, D.; Patra, R.C. [Division of Medicine, Indian Veterinary Research Institute, Izatnagar-243122 (India); Pal, Satya [Env. Eng. Lab., Deptt. of Civil Engineering, I.I.T., Roorkee-247667 (India)

2009-09-01

An experiment was conducted to investigate bioaccumulation potential of cadmium (Cd) and changes in oxidative stress indices in liver and kidney tissues from Cd-exposed catfish (Clarias batrachus) with or without simultaneous treatment of water with ascorbic acid, garlic extract or taurine. C. batrachus (n = 324) with average length of 20 {+-} 4 cm and weight of 86 {+-} 5 g were used for the present investigation. Fishes were divided into nine groups (I to IX) each comprising 36 fishes. The fishes of groups II, III, IV and V were challenged with 5 ppm of cadmium chloride monohydrate (CdCl{sub 2}.H{sub 2}O), whereas groups VI, VII, VIII and IX were exposed to 10 ppm CdCl{sub 2}.H{sub 2}O solution for a period of 45 days. Group I was kept as negative control and the fishes of this group were maintained in water containing no added Cadmium. Group II and VI were maintained as Cd exposed non treated control to serve as positive controls. Fishes of III and VII, IV and VIII, V and IX received ascorbic acid (5 ppm), extract of dried garlic (5 ppm) or taurine (5 ppm), respectively during the entire experiment period. The concentrations of Cd in liver and kidney increased significantly following exposure to Cd and the level continued to rise with the increase in exposure duration. Treatment of tank water with ascorbic acid, garlic or taurine significantly reduced the Cd concentrations in tissues compared to the positive control group, but the level in Cd exposed groups was greater than the negative control group. Fishes exposed to Cd and treated with ascorbic acid, garlic or taurine had reduced oxidative stress as evidenced from lower concentration of lipid peroxides and higher activities of superoxide dismutase and catalase in liver, kidney and erythrocytes compared to fishes exposed to Cd. The reduction in Cd induced oxidative stress was highest in ascorbic acid treated group followed by garlic and taurine treatment. The results suggest that ascorbic acid, garlic and

Ascorbic acid, garlic extract and taurine alleviate cadmium-induced oxidative stress in freshwater catfish (Clarias batrachus)

International Nuclear Information System (INIS)

Kumar, Puneet; Prasad, Y.; Patra, A.K.; Ranjan, R.; Swarup, D.; Patra, R.C.; Pal, Satya

2009-01-01

An experiment was conducted to investigate bioaccumulation potential of cadmium (Cd) and changes in oxidative stress indices in liver and kidney tissues from Cd-exposed catfish (Clarias batrachus) with or without simultaneous treatment of water with ascorbic acid, garlic extract or taurine. C. batrachus (n = 324) with average length of 20 ± 4 cm and weight of 86 ± 5 g were used for the present investigation. Fishes were divided into nine groups (I to IX) each comprising 36 fishes. The fishes of groups II, III, IV and V were challenged with 5 ppm of cadmium chloride monohydrate (CdCl 2 .H 2 O), whereas groups VI, VII, VIII and IX were exposed to 10 ppm CdCl 2 .H 2 O solution for a period of 45 days. Group I was kept as negative control and the fishes of this group were maintained in water containing no added Cadmium. Group II and VI were maintained as Cd exposed non treated control to serve as positive controls. Fishes of III and VII, IV and VIII, V and IX received ascorbic acid (5 ppm), extract of dried garlic (5 ppm) or taurine (5 ppm), respectively during the entire experiment period. The concentrations of Cd in liver and kidney increased significantly following exposure to Cd and the level continued to rise with the increase in exposure duration. Treatment of tank water with ascorbic acid, garlic or taurine significantly reduced the Cd concentrations in tissues compared to the positive control group, but the level in Cd exposed groups was greater than the negative control group. Fishes exposed to Cd and treated with ascorbic acid, garlic or taurine had reduced oxidative stress as evidenced from lower concentration of lipid peroxides and higher activities of superoxide dismutase and catalase in liver, kidney and erythrocytes compared to fishes exposed to Cd. The reduction in Cd induced oxidative stress was highest in ascorbic acid treated group followed by garlic and taurine treatment. The results suggest that ascorbic acid, garlic and taurine have potential to

Antioxidative Activity of Colostrum and Human Milk: Effects of Pasteurization and Storage.

Science.gov (United States)

Marinković, Vesna; Ranković-Janevski, Milica; Spasić, Snežana; Nikolić-Kokić, Aleksandra; Lugonja, Nikoleta; Djurović, Dijana; Miletić, Srdjan; Vrvić, Miroslav M; Spasojević, Ivan

2016-06-01

Milk banks collect, pasteurize, and freeze/store human milk. The processing may alter redox properties of milk, but the effects have not been fully examined. We collected 10 mature milk and 10 colostrum samples and applied a battery of biochemical assays and electron paramagnetic resonance spectroscopy to inspect changes that milk undergoes with pasteurization and 30 days storage at -20°C. Pasteurization and storage of raw milk did not affect total nonenzymatic antioxidative capacity, but specific components and features were altered. Urate radical and ascorbyl radical emerge as products of exposure of milk to hydroxyl radical-generating system. Processing shifted the load of antioxidative activity from ascorbate to urate and lowered the capacity of milk to diminish hydroxyl radical. Pasteurization caused a significant drop in the activity of 2 major antioxidative enzymes-superoxide dismutase and glutathione peroxidase, whereas freezing/storage of raw milk affected only superoxide dismutase. Colostrum showed drastically higher total nonenzymatic antioxidative capacity, hydroxyl radical scavenging ability, and glutathione reductase activity compared with mature milk. Pasteurization and storage affect nonenzymatic and enzymatic antioxidative agents in human milk. It appears that nonenzymatic antioxidative systems in colostrum and milk are different. The effects of processing may be partially compensated by fortification/spiking with ascorbate before use.

Involvement of an antioxidant defense system in the adaptive response to cadmium in maize seedlings (Zea mays L.).

Science.gov (United States)

Xu, Xianghua; Liu, Cuiying; Zhao, Xiaoyan; Li, Renying; Deng, Wenjing

2014-11-01

Chemical and biological analyses were used to investigate the growth response and antioxidant defense mechanism of maize seedlings (Zea mays L.) grown in soils with 0-100 mg kg(-1) Cd. Results showed that maize seedlings have strong abilities to accumulate and tolerate high concentrations of Cd. For soil with 50 mg kg(-1) Cd, the Cd contents in roots and shoots of maize seedlings are as large as 295.6 and 153.0 mg kg(-1) DW, respectively, without visible symptoms of toxicity. Lower soil Cd concentrations lead to a decrease in reduced glutathione (GSH) content in leaves of maize seedlings, whereas higher soil Cd concentrations resulted in an increase in the activities of superoxide dismutase, guaiacol peroxidase, catalase, and ascorbate peroxidase. Maize seedlings have strong capacities to adapt to low concentrations of Cd by consuming GSH and to develop an antioxidative enzyme system to defend against high-Cd stress.

Zinc affects differently growth, photosynthesis, antioxidant enzyme activities and phytochelatin synthase expression of four marine diatoms.

Science.gov (United States)

Nguyen-Deroche, Thi Le Nhung; Caruso, Aurore; Le, Thi Trung; Bui, Trang Viet; Schoefs, Benoît; Tremblin, Gérard; Morant-Manceau, Annick

2012-01-01

Zinc-supplementation (20 μM) effects on growth, photosynthesis, antioxidant enzyme activities (superoxide dismutase, ascorbate peroxidase, catalase), and the expression of phytochelatin synthase gene were investigated in four marine diatoms (Amphora acutiuscula, Nitzschia palea, Amphora coffeaeformis and Entomoneis paludosa). Zn-supplementation reduced the maximum cell density. A linear relationship was found between the evolution of gross photosynthesis and total chlorophyll content. The Zn treatment decreased the electron transport rate except in A. coffeaeformis and in E. paludosa at high irradiance. A linear relationship was found between the efficiency of light to evolve oxygen and the size of the light-harvesting antenna. The external carbonic anhydrase activity was stimulated in Zn-supplemented E. paludosa but was not correlated with an increase of photosynthesis. The total activity of the antioxidant enzymes did not display any clear increase except in ascorbate peroxidase activity in N. palea. The phytochelatin synthase gene was identified in the four diatoms, but its expression was only revealed in N. palea, without a clear difference between control and Zn-supplemented cells. Among the four species, A. paludosa was the most sensitive and A. coffeaeformis, the most tolerant. A. acutiuscula seemed to be under metal starvation, whereas, to survive, only N. palea developed several stress responses.

Zinc Affects Differently Growth, Photosynthesis, Antioxidant Enzyme Activities and Phytochelatin Synthase Expression of Four Marine Diatoms

Directory of Open Access Journals (Sweden)

Thi Le Nhung Nguyen-Deroche

2012-01-01

Full Text Available Zinc-supplementation (20 μM effects on growth, photosynthesis, antioxidant enzyme activities (superoxide dismutase, ascorbate peroxidase, catalase, and the expression of phytochelatin synthase gene were investigated in four marine diatoms (Amphora acutiuscula, Nitzschia palea, Amphora coffeaeformis and Entomoneis paludosa. Zn-supplementation reduced the maximum cell density. A linear relationship was found between the evolution of gross photosynthesis and total chlorophyll content. The Zn treatment decreased the electron transport rate except in A. coffeaeformis and in E. paludosa at high irradiance. A linear relationship was found between the efficiency of light to evolve oxygen and the size of the light-harvesting antenna. The external carbonic anhydrase activity was stimulated in Zn-supplemented E. paludosa but was not correlated with an increase of photosynthesis. The total activity of the antioxidant enzymes did not display any clear increase except in ascorbate peroxidase activity in N. palea. The phytochelatin synthase gene was identified in the four diatoms, but its expression was only revealed in N. palea, without a clear difference between control and Zn-supplemented cells. Among the four species, A. paludosa was the most sensitive and A. coffeaeformis, the most tolerant. A. acutiuscula seemed to be under metal starvation, whereas, to survive, only N. palea developed several stress responses.

Effects of cadmium on ultrastructure and antioxidative defense system in hyperaccumulator and non-hyperaccumulator ecotypes of Sedum alfredii Hance

International Nuclear Information System (INIS)

Jin Xiaofen; Yang Xiaoe; Islam, Ejazul; Liu Dan; Mahmood, Qaisar

2008-01-01

Plant growth, ultrastructural and antioxidant adaptations and glutathione biosynthesis in Cd-hyperaccumulating ecotype Sedum alfredii Hance (HE) countering high Cd environment were investigated and compared with its non Cd-hyperaccumulating ecotype (NHE). Cadmium exposure resulted in significant ultrastructural changes in root meristem and leaf mesophyll cells of S. alfredii, but damage was more pronounced in NHE even when Cd concentrations were one-tenth of those applied to HE. Cadmium stress damaged chloroplasts causing imbalanced lamellae formation coupled with early leaf senescence. Histochemical results revealed that glutathione (GSH) biosynthesis inhibition led to overproduction of hydrogen peroxide (H 2 O 2 ) and superoxide radical (O 2 · - ) in HE but not in NHE. Differences were noted in both HE and NHE for catalase (CAT), guaiacol peroxidase (GPX), ascorbate peroxidase (APX) and glutathione reductase (GR) activities under various Cd stress levels. No relationship was found between antioxidative defense capacity including activities of superoxide dismutase (SOD), CAT, GPX, APX and GR as well as ascorbic acid (AsA) contents and Cd tolerance in the two ecotypes of S. alfredii. The GSH biosynthesis induction in root and shoot exposed to elevated Cd conditions may be involved in Cd tolerance and hyperaccumulation in HE of S. alfredii H

Higher transcription levels in ascorbic acid biosynthetic and recycling genes were associated with higher ascorbic acid accumulation in blueberry.

Science.gov (United States)

Liu, Fenghong; Wang, Lei; Gu, Liang; Zhao, Wei; Su, Hongyan; Cheng, Xianhao

2015-12-01

In our preliminary study, the ripe fruits of two highbush blueberry (Vaccinium corymbosum L.) cultivars, cv 'Berkeley' and cv 'Bluecrop', were found to contain different levels of ascorbic acid. However, factors responsible for these differences are still unknown. In the present study, ascorbic acid content in fruits was compared with expression profiles of ascorbic acid biosynthetic and recycling genes between 'Bluecrop' and 'Berkeley' cultivars. The results indicated that the l-galactose pathway was the predominant route of ascorbic acid biosynthesis in blueberry fruits. Moreover, higher expression levels of the ascorbic acid biosynthetic genes GME, GGP, and GLDH, as well as the recycling genes MDHAR and DHAR, were associated with higher ascorbic acid content in 'Bluecrop' compared with 'Berkeley', which indicated that a higher efficiency ascorbic acid biosynthesis and regeneration was likely to be responsible for the higher ascorbic acid accumulation in 'Bluecrop'. Copyright © 2015 Elsevier Ltd. All rights reserved.

Electrocatalytic analysis of superoxide anion radical using nitrogen-doped graphene supported Prussian Blue as a biomimetic superoxide dismutase

International Nuclear Information System (INIS)

Liu, Tingting; Niu, Xiangheng; Shi, Libo; Zhu, Xiang; Zhao, Hongli; Lana, Minbo

2015-01-01

Graphical abstract: Prussian Blue (PB) cubes supported on nitrogen-doped graphene sheets (NGS) were synthesized using a simple and scalable method, and the utilization of the PB-NGS hybrid as an efficient superoxide dismutase mimic in the electrochemical sensing of O 2 ·− was demonstrated. - Highlights: • Facile and scalable synthesis of Prussian Blue cubes supported on nitrogen-doped graphene; • Nitrogen-doped graphene supported Prussian Blue as an efficient biomimetic superoxide dismutase for the electrocatalytic sensing of superoxide anion; • Good sensitivity, excellent selectivity and attractive long-term stability for superoxide anion sensing. - Abstract: Considering the double-sided roles of superoxide anion radical, monitoring of its track in living systems is attracting increasing academic and practical interest. Here we synthesized Prussian Blue (PB) cubes that were supported on nitrogen-doped graphene sheets (NGS) using a facile and scalable method, and explored their potential utilization in the electrochemical sensing of superoxide anion. As an efficient superoxide dismutase mimic, direct electron transfer of the prepared PB-NGS hybrid immobilized on a screen-printed gold electrode was harvested in physiological media. With the bifunctional activities, the synthetic mimic could catalyze the dismutation of superoxide anion via the redox cycle of active iron. By capturing the electro-reduction amperometric responses of superoxide anion radical to hydrogen peroxide in the cathodic polarization, highly sensitive determination (a sensitivity of as high as 0.32 μA cm −2 μM −1 ) of the target was achieved, with no interference from common coexisting species including ascorbic acid, dopamine, and uric acid observed. Compared to natural superoxide dismutases, the artificial enzyme mimic exhibited favorable activity stability, indicating its promising applications in the in vivo long-term monitoring of superoxide anion

Arabidopsis thaliana peroxidase N

DEFF Research Database (Denmark)

Mirza, Osman Asghar; Henriksen, A; Ostergaard, L

2000-01-01

The structure of the neutral peroxidase from Arabidopsis thaliana (ATP N) has been determined to a resolution of 1.9 A and a free R value of 20.5%. ATP N has the expected characteristic fold of the class III peroxidases, with a C(alpha) r.m.s.d. of 0.82 A when compared with horseradish peroxidase C...... (HRP C). HRP C is 54% identical to ATP N in sequence. When the structures of four class III plant peroxidases are superimposed, the regions with structural differences are non-randomly distributed; all are located in one half of the molecule. The architecture of the haem pocket of ATP N is very similar...... to that of HRP C, in agreement with the low small-molecule substrate specificity of all class III peroxidases. The structure of ATP N suggests that the pH dependence of the substrate turnover will differ from that of HRP C owing to differences in polarity of the residues in the substrate-access channel. Since...

21 CFR 582.3013 - Ascorbic acid.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Ascorbic acid. 582.3013 Section 582.3013 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS... Ascorbic acid. (a) Product. Ascorbic acid. (b) Conditions of use. This substance is generally recognized as...

Specificity versus redundancy in the RAP2.4 transcription factor family of Arabidopsis thaliana: transcriptional regulation of genes for chloroplast peroxidases.

Science.gov (United States)

Rudnik, Radoslaw; Bulcha, Jote Tafese; Reifschneider, Elena; Ellersiek, Ulrike; Baier, Margarete

2017-08-23

The Arabidopsis ERFIb / RAP2.4 transcription factor family consists of eight members with highly conserved DNA binding domains. Selected members have been characterized individually, but a systematic comparison is pending. The redox-sensitive transcription factor RAP2.4a mediates chloroplast-to-nucleus redox signaling and controls induction of the three most prominent chloroplast peroxidases, namely 2-Cys peroxiredoxin A (2CPA) and thylakoid- and stromal ascorbate peroxidase (tAPx and sAPx). To test the specificity and redundancy of RAP2.4 transcription factors in the regulation of genes for chloroplast peroxidases, we compared the DNA-binding sites of the transcription factors in tertiary structure models, analyzed transcription factor and target gene regulation by qRT-PCR in RAP2.4, 2-Cys peroxiredoxin and ascorbate peroxidase T-DNA insertion lines and RAP2.4 overexpressing lines of Arabidopsis thaliana and performed promoter binding studies. All RAP2.4 proteins bound the tAPx promoter, but only the four RAP2.4 proteins with identical DNA contact sites, namely RAP2.4a, RAP2.4b, RAP2.4d and RAP2.4h, interacted stably with the redox-sensitive part of the 2CPA promoter. Gene expression analysis in RAP2.4 knockout lines revealed that RAP2.4a is the only one supporting 2CPA and chloroplast APx expression. Rap2.4h binds to the same promoter region as Rap2.4a and antagonizes 2CPA expression. Like the other six RAP2.4 proteins, Rap2.4 h promotes APx mRNA accumulation. Chloroplast ROS signals induced RAP2.4b and RAP2.4d expression, but these two transcription factor genes are (in contrast to RAP2.4a) insensitive to low 2CP availability, and their expression decreased in APx knockout lines. RAP2.4e and RAP2.4f gradually responded to chloroplast APx availability and activated specifically APx expression. These transcription factors bound, like RAP2.4c and RAP2.4g, the tAPx promoter, but hardly the 2CPA promoter. The RAP2.4 transcription factors form an environmentally and

21 CFR 182.8013 - Ascorbic acid.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Ascorbic acid. 182.8013 Section 182.8013 Food and... CONSUMPTION (CONTINUED) SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients § 182.8013 Ascorbic acid. (a) Product. Ascorbic acid. (b) Conditions of use. This substance is generally recognized as safe when used in...

21 CFR 582.5013 - Ascorbic acid.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Ascorbic acid. 582.5013 Section 582.5013 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS... 1 § 582.5013 Ascorbic acid. (a) Product. Ascorbic acid. 1 Amino acids listed in this subpart may be...

Regiospecificity determinants of human heme oxygenase: differential NADPH- and ascorbate-dependent heme cleavage by the R183E mutant.

Science.gov (United States)

Wang, Jinling; Lad, Latesh; Poulos, Thomas L; Ortiz de Montellano, Paul R

2005-01-28

The ability of the human heme oxygenase-1 (hHO-1) R183E mutant to oxidize heme in reactions supported by either NADPH-cytochrome P450 reductase or ascorbic acid has been compared. The NADPH-dependent reaction, like that of wild-type hHO-1, yields exclusively biliverdin IXalpha. In contrast, the R183E mutant with ascorbic acid as the reductant produces biliverdin IXalpha (79 +/- 4%), IXdelta (19 +/- 3%), and a trace of IXbeta. In the presence of superoxide dismutase and catalase, the yield of biliverdin IXdelta is decreased to 8 +/- 1% with a corresponding increase in biliverdin IXalpha. Spectroscopic analysis of the NADPH-dependent reaction shows that the R183E ferric biliverdin complex accumulates, because reduction of the iron, which is required for sequential iron and biliverdin release, is impaired. Reversal of the charge at position 183 makes reduction of the iron more difficult. The crystal structure of the R183E mutant, determined in the ferric and ferrous-NO bound forms, shows that the heme primarily adopts the same orientation as in wild-type hHO-1. The structure of the Fe(II).NO complex suggests that an altered active site hydrogen bonding network supports catalysis in the R183E mutant. Furthermore, Arg-183 contributes to the regiospecificity of the wild-type enzyme, but its contribution is not critical. The results indicate that the ascorbate-dependent reaction is subject to a lower degree of regiochemical control than the NADPH-dependent reaction. Ascorbate may be able to reduce the R183E ferric and ferrous dioxygen complexes in active site conformations that cannot be reduced by NADPH-cytochrome P450 reductase.

Fate of the synergistic antioxidant system ascorbic acid, lecithin, and tocopherol in mayonnaise : Partition of ascorbic acid

DEFF Research Database (Denmark)

Meyer, A.S.; Jacobsen, Charlotte Munch

1996-01-01

The distribution of ascorbic acid between the lipid and aqueous phase was investigated in mayonnaises enriched with fish oil containing a synergistic antioxidant mixture of ascorbic acid, lecithin and gamma-tocopherol, i.e., the A/L/T system (Loliger and Saucy 1989). The ascorbic acid was found...... to be located in the aqueous phase indicating that the A/L/T system broke down in mayonnaises. Based on the hypothesis that synergistic antioxidant action between ascorbic acid, lecithin and tocopherol requires that the three components are in close assembly, the results offer an explanation as to why the A...

Differential Antioxidative Responses to Water Deficit Among four Barley (Hordeum vulgare L. Genotypes

Directory of Open Access Journals (Sweden)

Z Amini

2013-08-01

Full Text Available Future climate changes are expected to increase risks of drought, which already represent the most common stress factor for stable barley (Hordeum vulgare L. production in Iran. Up to now, extensive research projects have been done to study effects of drought stress on the antioxidant enzyme activity. While there is a few works of such studies on the field condition. In order to study of water deficit effects on the antioxidant enzymes activities as a secondary stress, we evaluate the effects of mild and severe drought stress on activities of antioxidative enzymes including superoxide dismutases, ascorbate peroxidase, catalase and peroxidase, among four barley genotypes, differing in the capacity to maintain the grain yield under drought condition during beginning on anthesis, kernel watery ripe and late milk stages under field condition. Results showed that drought increased the activity of antioxidant enzymes in all genotypes. At beginning of anthesis, POX activity of Q22 was higher than it in other genotypes ( P

Chitosan Coating: A Postharvest Treatment to Delay Oxidative Stress in Loquat Fruits during Cold Storage

Directory of Open Access Journals (Sweden)

Giuseppina Adiletta

2018-04-01

Full Text Available Loquat is a non-climacteric fruit consumed fresh for its essential nutrients and phytochemical compounds. In this study, the effects of chitosan coating (1% w/v on changes in the enzymatic antioxidant and membrane damage in three loquat selections (CREAFRC-S18; CREAFRC-S35 and CREAFRC-S36 and three loquat cultivars (Golden Nugget, Algerie and Nespolone rosso di Trabia stored at 7 °C over 21 days were evaluated. Chitosan treatment enhanced the activities of superoxide dismutase, catalase and ascorbate peroxidase. Moreover, this treatment inhibited polyphenol oxidase and guaiacol peroxidase activities, extending the storage life of loquat. Chitosan also preserved membrane integrity by inhibiting lipoxygenase activity and malondialdehyde accumulation. Principal component analysis provided a global view of the responses of both loquat selections and cultivars to the postharvest chitosan coating and storage temperature. These findings suggest that chitosan treatment could be a valid tool for improving the activity of antioxidant enzymes, preserving the enzymatic browning of loquat fruits.

Arbuscular Mycorrhizal Fungi Enhance Basil Tolerance to Salt Stress through Improved Physiological and Nutritional Status

International Nuclear Information System (INIS)

Salwa, A.; Abeer, H.; Alqarawi, A. A.; Abdullah, E.F.; Egamberdieva, D.

2016-01-01

Pot experiments were conducted to evaluate the influence of salinity on some physio-biochemical traits in sweet basil (Ocimum basilicum L.) cultivars with contrasting salt stress tolerance and to determine the role of arbuscular mycorrhizal fungi (AMF) in ameliorating the salt stress in plant. Salt stress (250 mM NaCl) reduced the colonization potential of AMF and inhibited photosynthetic pigments, chlorophyll and carotenoids in plant tissue. AMF inoculated plants contained higher level of chlorophyll pigments. Salt stressed plants showed increased lipid peroxidation, antioxidant enzyme activities like superoxide dismutase (SOD), ascorbate peroxidase (APX) and peroxidase (POD). Plants inoculated with AMF showed lower lipid peroxidation and enhanced antioxidant enzyme activities. Moreover, the content of lipids, proline, and soluble sugars in basil plants was improved with AMF inoculation. AMF inoculation reduced accumulation of Na+ and improved nutrient acquisition. In conclusion, AMF were capable to reduce oxidative stress via supporting of the antioxidant system. Salt tolerant cultivar showed higher antioxidant enzyme activity and accumulation of osmolytes. (author)

Enzymatic browning and antioxidant activities in harvested litchi fruit as influenced by apple polyphenols.

Science.gov (United States)

Zhang, Zhengke; Huber, Donald J; Qu, Hongxia; Yun, Ze; Wang, Hui; Huang, Zihui; Huang, Hua; Jiang, Yueming

2015-03-15

'Guiwei' litchi fruit were treated with 5 ga.i. L(-1) apple polyphenols (APP) and then stored at 25°C to investigate the effects on pericarp browning. APP treatment effectively reduced pericarp browning and retarded the loss of red colour. APP-treated fruit exhibited higher levels of anthocyanins and cyanidin-3-rutinoside, which correlated with suppressed anthocyanase activity. APP treatment also maintained membrane integrity and reduced oxidative damage, as indicated by a lower relative leakage rate, malondialdehyde content, and reactive oxygen species (ROS) generation. The data suggest that decompartmentalisation of peroxidase and polyphenoloxidase and respective browning substrates was reduced. In addition, APP treatment enhanced the activities of antioxidant enzymes (superoxide dismutase, catalase, ascorbate peroxidase and glutathione reductase), as well as non-enzymatic antioxidant capacity (DPPH radical-scavenging activity and reducing power), which might be beneficial in scavenging ROS. We propose that APP treatment is a promising safe strategy for controlling postharvest browning of litchi fruit. Copyright © 2014 Elsevier Ltd. All rights reserved.

Tumorigenicity of sodium ascorbate in male rats.

Science.gov (United States)

Cohen, S M; Anderson, T A; de Oliveira, L M; Arnold, L L

1998-06-15

Sodium ascorbate, like other sodium salts such as saccharin, glutamate, and bicarbonate, produces urinary alterations when fed at high doses to rats, which results in mild superficial urothelial cytotoxicity and regeneration but not tumors in a standard 2-year bioassay. Sodium saccharin was shown to produce a low incidence of bladder tumors in rats if administered in a two-generation bioassay. In the present study, we evaluated sodium ascorbate in a two-generation bioassay that involved feeding to the male and female parental F344 rats for 4 weeks before mating, feeding the dams during gestation and lactation, and then feeding the weaned (at 28 days of age) male F1 generation rats for the remainder of their lifetime (up to 128 weeks of the experiment). Dietary levels of 1.0, 5.0, and 7.0% sodium ascorbate were tested. At 5.0 and 7.0% sodium ascorbate, there was an increase in urinary bladder urothelial papillary and nodular hyperplasia and the induction of a few papillomas and carcinomas. There was a dose-responsive increase in renal pelvic calcification and hyperplasia and inhibition of the aging nephropathy of rats even at the level of 1% sodium ascorbate. Because the short-term urothelial effects of sodium ascorbate in rats are inhibited by treatments producing urinary acidification to pH sodium ascorbate to evaluate the long-term effects. The combination of 7.0% sodium ascorbate plus 2.78% NH4Cl in the diet was toxic, and the group was terminated early during the course of the experiment. The group fed 5.0% sodium ascorbate plus 2.04% NH4Cl showed complete inhibition of the urothelial effects of sodium ascorbate and significant inhibition of its renal effects. We also demonstrated the presence of a calcium phosphate-containing urinary precipitate in rats fed sodium ascorbate at all doses, in a dose-responsive manner. The formation of the precipitate was inhibited by coadministration with NH4Cl. The proliferative effects of sodium ascorbate on the male rat

Colorimetric Glucose Assay Based on Magnetic Particles Having Pseudo-peroxidase Activity and Immobilized Glucose Oxidase.

Science.gov (United States)

Martinkova, Pavla; Opatrilova, Radka; Kruzliak, Peter; Styriak, Igor; Pohanka, Miroslav

2016-05-01

Magnetic particles (MPs) are currently used as a suitable alternative for peroxidase in the construction of novel biosensors, analytic and diagnostic methods. Their better chemical and thermal stabilities predestine them as appropriate pseudo-enzymatic catalysts. In this point of view, our research was focused on preparation of simply and fast method for immobilization of glucose oxidase onto surface of MPs with peroxidase-like activity. Spectrophotometric method (wavelength 450 nm) optimized for glucose determination using modified MPs has been successfully developed. Concentration curve for optimization of method was assayed, and Michaelis-Menten constant (K m) calculated, maximum reaction rate (V max), limit of detection, and correlation coefficient were determined to be 0.13 mmol/l (2.34 mg/dl), 1.79 pkat, 3.74 µmol/l (0.067 mg/dl), and 0.996, respectively. Interferences of other sugars such as sucrose, sorbitol, deoxyribose, maltose, and fructose were determined as well as effect of substances presenting in plasma (ascorbic acid, reduced glutathione, trolox, and urea). Results in comparison with positive and negative controls showed no interferences of the other sugars and no influence of plasma substances to measuring of glucose. The constructed method showed corresponding results with linear dependence and a correlation coefficient of 0.997. Possibility of repeated use of modified MPs was successfully proved.

Antioxidant enzymes expression in Pseudomonas aeruginosa exposed to UV-C radiation.

Science.gov (United States)

Salma, Kloula Ben Ghorbal; Lobna, Maalej; Sana, Khefacha; Kalthoum, Chourabi; Imene, Ouzari; Abdelwaheb, Chatti

2016-07-01

It was well known that, UV-C irradiation increase considerably the reactive oxygen species (ROS) levels in eukaryotic and prokaryotic organisms. In the enzymatic ROS-scavenging pathways, superoxide dismutase (SOD), Catalase (CAT), and peroxidase (POX) were developed to deal with oxidative stress. In this study, we investigated the effects of UV-C radiations on antioxidant enzymes (catalase, superoxide dismutase, and peroxidases) expression in Pseudomonas aeruginosa. Catalase, superoxide dismutase, and peroxidases activities were determined spectrophotometrically. Isozymes of superoxide dismutase were revealed by native gel activity staining method. Lipid peroxidation was determined by measuring malondialdehyde formation. Our results showed that superoxide dismutase, catalase and peroxidase activities exhibited a gradual increase during the exposure time (30 min). However, the superoxide dismutase activity was maximized at 15 min. Native gel activity staining assays showed the presence of three superoxide dismutase isozymes. The iron-cofactored isoform activity was altered after exposure to UV-C stress. These finding suggest that catalase and peroxidase enzymes have the same importance toward UV-C rays at shorter and longer exposure times and this may confer additional protection to superoxide dismutase from damage caused by lipid peroxidation. Moreover, our data demonstrate the significant role of the antioxidant system in the resistance of this important human pathogen. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Oxidative Stress and Antioxidants in Tomato (Solanum lycopersicum) Plants Subjected to Boron Toxicity

Science.gov (United States)

Cervilla, Luis M.; Blasco, Begoña; Ríos, Juan J.; Romero, Luis; Ruiz, Juan M.

2007-01-01

Background and Aims Boron (B) toxicity triggers the formation of reactive oxygen species in plant tissues. However, there is still a lack of knowledge as to how B toxicity affects the plant antioxidant defence system. It has been suggested that ascorbate could be important against B stress, although existing information is limited in this respect. The objective of this study was to analyse how ascorbate and some other components of the antioxidant network respond to B toxicity. Methods Two tomato (Solanum lycopersicum) cultivars (‘Kosaco’ and ‘Josefina’) were subjected to 0·05 (control), 0·5 and 2 mm B. The following were studied in leaves: dry weight; relative leaf growth rate; total and free B; H2O2; malondialdehyde; ascorbate; glutathione; sugars; total non-enzymatic antioxidant activity, and the activity of superoxide dismutase, catalase, ascorbate peroxidase, monodehydroascorbate reductase, dehydroascorbate reductase, glutathione reductase, ascorbate oxidase and l-galactose dehydrogenase. Key Results The B-toxicity treatments diminished growth and boosted the amount of B, malondialdehyde and H2O2 in the leaves of the two cultivars, these trends being more pronounced in ‘Josefina’ than in ‘Kosaco’. B toxicity increased ascorbate concentration in both cultivars and increased glutathione only in ‘Kosaco’. Activities of antioxidant- and ascorbate-metabolizing enzymes were also induced. Conclusions High B concentration in the culture medium provokes oxidative damage in tomato leaves and induces a general increase in antioxidant enzyme activity. In particular, B toxicity increased ascorbate pool size. It also increased the activity of l-galactose dehydrogenase, an enzyme involved in ascorbate biosynthesis, and the activity of enzymes of the Halliwell–Asada cycle. This work therefore provides a starting point towards a better understanding of the role of ascorbate in the plant response against B stress. PMID:17660516

IMPACT OF FOLIAR APPLICATION OF ASCORBIC ACID AND α-TOCOPHEROL ON ANTIOXIDANT ACTIVITY AND SOME BIOCHEMICAL ASPECTS OF FLAX CULTIVARS UNDER SALINITY STRESS

Directory of Open Access Journals (Sweden)

Hala M.S. El-Bassiouny

2015-05-01

Full Text Available ABSTRACT The interactive effects of saline water (2000, 4000 and 6000 mg/l and foliar application of 400 mg/l of ascorbic acid (Asc or α – tocopherol (α-Toco on three flax cultivars (Sakha 3, Giza 8 and Ariane were conducted during two successive seasons (2011 and 2012. The results showed that, total soluble carbohydrates, free amino acids, proline contents were significantly increased with increasing salinity levels in all three tested cultivars except free amino acid content of Giza 8 which showed a non significant decrease. While, nucleic acids (DNA and RNA showed significant decreases compared with the corresponding controls. Moreover, applications of vitamins (Asc or α-Toco as foliar spraying increased all mentioned contents compared to the corresponding salinity levels. On the other hand, lipid peroxidation, and activity levels of polyphenol oxidase (PPO, peroxidase (POX and catalase (CAT enzymes showed progressive significant increases with increasing salinity levels of all tested three cultivars, while the behaviour of superoxide dismutase (SOD activity showed an opposite response as compared with the control in Sakha 3 and Giza 8. Treatments with Asc or α-Toco induced significant reduction in lipid peroxidation and activities of PPO and POX of all three tested cultivars. Meanwhile, SOD increased in all three cultivars, and CAT activities increased only in Sakha 3 cultivar under salt stress as compared with reference controls. Some modifications are observed in protein patterns hence some proteins were disappeared, while certain other proteins were selectively increased and synthesis of a new set of proteins were induced, some of these responses were observed under treatments and salinity, while others were induced by either treatments or salinity.

Zinc-induced differential oxidative stress and antioxidant responses in Chlorella sorokiniana and Scenedesmus acuminatus.

Science.gov (United States)

Hamed, Seham M; Zinta, Gaurav; Klöck, Gerd; Asard, Han; Selim, Samy; AbdElgawad, Hamada

2017-06-01

Algae are frequently exposed to toxic metals, and zinc (Zn) is one of the major toxicants present. We exposed two green microalgae, Chlorella sorokiniana and Scenedesmus acuminatus, to sub-lethal concentrations (1.0 and 0.6mM) of Zn for seven days. Algal responses were analysed at the level of growth, oxidative stress, and antioxidants. Growth parameters such as cell culture yield and pigment content were less affected by Zn in C. sorokiniana, despite the fact that this alga accumulated more zinc than S. acuminatus. Also, C. sorokiniana, but not S. acuminatus, was able to acclimatize during long-term exposure to toxic concentrations of the test metals (specific growth rate (µ) was 0.041/day and total chlorophyll was 14.6mg/mL). Although, Zn induced oxidative stress in both species, C. sorokiniana experienced less stress than S. acuminatus. This could be explained by a higher accumulation of antioxidants in C. sorokiniana, where flavonoids, polyphenols, tocopherols, glutathione (GSH) and ascorbate (ASC) content increased. Moreover, antioxidant enzymes glutathione S transferase (GST), glutathione reductase (GR), superoxide dismutase (SOD), peroxidase (POX) and ascorbate peroxidase (APX), showed increased activities in C. sorokiniana. In addition to, and probably also underlying, the higher Zn tolerance in C. sorokiniana, this alga also showed higher Zn biosorption capacity. Use of C. sorokiniana as a bio-remediator, could be considered. Copyright © 2017 Elsevier Inc. All rights reserved.

Polymorphisms in sodium-dependent vitamin C transporter genes and plasma, aqueous humor and lens nucleus ascorbate concentrations in an ascorbate depleted setting.

Science.gov (United States)

Senthilkumari, Srinivasan; Talwar, Badri; Dharmalingam, Kuppamuthu; Ravindran, Ravilla D; Jayanthi, Ramamurthy; Sundaresan, Periasamy; Saravanan, Charu; Young, Ian S; Dangour, Alan D; Fletcher, Astrid E

2014-07-01

We have previously reported low concentrations of plasma ascorbate and low dietary vitamin C intake in the older Indian population and a strong inverse association of these with cataract. Little is known about ascorbate levels in aqueous humor and lens in populations habitually depleted of ascorbate and no studies in any setting have investigated whether genetic polymorphisms influence ascorbate levels in ocular tissues. Our objectives were to investigate relationships between ascorbate concentrations in plasma, aqueous humor and lens and whether these relationships are influenced by Single Nucleotide Polymorphisms (SNPs) in sodium-dependent vitamin C transporter genes (SLC23A1 and SLC23A2). We enrolled sixty patients (equal numbers of men and women, mean age 63 years) undergoing small incision cataract surgery in southern India. We measured ascorbate concentrations in plasma, aqueous humor and lens nucleus using high performance liquid chromatography. SLC23A1 SNPs (rs4257763, rs6596473) and SLC23A2 SNPs (rs1279683 and rs12479919) were genotyped using a TaqMan assay. Patients were interviewed for lifestyle factors which might influence ascorbate. Plasma vitamin C was normalized by a log10 transformation. Statistical analysis used linear regression with the slope of the within-subject associations estimated using beta (β) coefficients. The ascorbate concentrations (μmol/L) were: plasma ascorbate, median and inter-quartile range (IQR), 15.2 (7.8, 34.5), mean (SD) of aqueous humor ascorbate, 1074 (545) and lens nucleus ascorbate, 0.42 (0.16) (μmol/g lens nucleus wet weight). Minimum allele frequencies were: rs1279683 (0.28), rs12479919 (0.30), rs659647 (0.48). Decreasing concentrations of ocular ascorbate from the common to the rare genotype were observed for rs6596473 and rs12479919. The per allele difference in aqueous humor ascorbate for rs6596473 was -217 μmol/L, p humor ascorbate were higher for the GG genotype of rs6596473: GG, β = 1460 compared to

Ascorbic acid in bronchial asthma

African Journals Online (AJOL)

1983-04-23

Apr 23, 1983 ... by comparing the pre-ascorbic acid results with those obtained 21/2 hours after the intravenous ... (ASO), C-reactive protein and antibodies to certain respiratory viruses. These investigations were ..... vitamin.6 However, other investigators were unable to detect any protective effects of ascorbic acid on the ...

Wound-induced expression of horseradish peroxidase.

Science.gov (United States)

Kawaoka, A; Kawamoto, T; Ohta, H; Sekine, M; Takano, M; Shinmyo, A

1994-01-01

Peroxidases have been implicated in the responses of plants to physiological stress and to pathogens. Wound-induced peroxidase of horseradish (Armoracia rusticana) was studied. Total peroxidase activity was increased by wounding in cell wall fractions extracted from roots, stems and leaves of horseradish. On the other hand, wounding decreased the peroxidase activity in the soluble fraction from roots. The enzyme activities of the basic isozymes were induced by wounding in horseradish leaves based on data obtained by fractionation of crude enzyme in isoelectric focusing gel electrophoresis followed by activity staining. We have previously isolated genomic clones for four peroxidase genes, namely, prxC1a, prxC1b, prxC2 and prxC3. Northern blot analysis using gene-specific probes showed that mRNA of prxC2, which encodes a basic isozyme, accumulated by wounding, while the mRNAs for other peroxidase genes were not induced. Tobacco (Nicotiana tabacum) plants were transformed with four chimeric gene constructs, each consisting of a promoter from one of the peroxidase genes and the β-glucuronidase (GUS) structural gene. High level GUS activity induced in response to wounding was observed in tobacco plants containing the prxC2-GUS construct.

Radioprotective effects of ascorbic acid in barley seeds

Energy Technology Data Exchange (ETDEWEB)

Conger, B V

1975-01-01

Experiments were conducted to test the radioprotective effects of a naturally occurring reducing agent, ascorbic acid, on seeds (caryopses) of barley, Hordeum vulgare L. emend Lam. Seeds were soaked either before or after ..gamma.. or fission neutron irradiation in distilled water or ascorbic acid solutions ranging in concentration from 0.01 to 1.00 M. Results are reported as percentage germination, seedling height, seedling growth reduction, and (in one experiment) percent of cells with chromosome aberrations. As evidenced by both reduced germination and seedling growth, ascorbic acid was toxic when seeds were soaked for 1 hr at ambient temperature prior to irradiation and then planted immediately. When seeds were soaked in ascorbic acid before irradiation and soaked after irradiation in air-bubbled water at 0/sup 0/C for 18 hr, the toxicity disappeared, and a protective effect (which increased with increasing ascorbic acid concentration) was observed for ..gamma.. and, to a lesser extent, for neutron irradiation. Additional studies suggested that the protective effect was related to reduced hydration of the embryos of seeds soaked in ascorbic acid. Also, no radioprotective effect was observed when seeds were presoaked for 2 or 16 hr in 0.01 M ascorbic acid solutions buffered at pH 3 or pH 7. A protective effect was observed for seeds of 1.5 percent water content soaked after irradiation in an oxygen-bubbled ascorbic acid solution of 0.5 M but was not observed for seeds soaked in nitrogen-bubbled ascorbic acid. The protective effect against oxygen-dependent damage may be a result of interaction of ascorbic acid with radiation-induced free radicals.

Comparative study on the inhibitory effects of antioxidant vitamins and radon on carbon tetrachloride-induced hepatopathy

International Nuclear Information System (INIS)

Kataoka, Takahiro; Nishiyama, Yuichi; Yamato, Keiko; Teraoka, Junichi; Morii, Yuji; Taguchi, Takehito; Yamaoka, Kiyonori; Sakoda, Akihiro; Ishimori, Yuu

2012-01-01

We have previously reported that radon inhalation activates anti-oxidative functions and inhibits carbon tetrachloride (CCl 4 )-induced hepatopathy. It has also been reported that antioxidant vitamins can inhibit CCl 4 -induced hepatopathy. In the current study, we examined the comparative efficacy of treatment with radon, ascorbic acid and α-tocopherol on CCl 4 -induced hepatopathy. Mice were subjected to intraperitoneal injection of CCl 4 after inhaling approximately 1000 or 2000 Bq/m 3 radon for 24 h, or immediately after intraperitoneal injection of ascorbic acid (100, 300, or 500 mg/kg bodyweight) or α-tocopherol (100, 300, or 500 mg/kg bodyweight). We estimated the inhibitory effects on CCl 4 -induced hepatopathy based on hepatic function-associated parameters, oxidative damage-associated parameters and histological changes. The results revealed that the therapeutic effects of radon inhalation were almost equivalent to treatment with ascorbic acid at a dose of 500 mg/kg or α-tocopherol at a dose of 300 mg/kg. The activities of superoxide dismutase, catalase, and glutathione peroxidase in the liver were significantly higher in mice exposed to radon than in mice treated with CCl 4 alone. These findings suggest that radon inhalation has an anti-oxidative effect against CCl 4 -induced hepatopathy similar to the anti-oxidative effects of ascorbic acid or α-tocopherol due to the induction of anti-oxidative functions. (author)

Interference of ascorbic acid with chemical analytes.

Science.gov (United States)

Meng, Qing H; Irwin, William C; Fesser, Jennifer; Massey, K Lorne

2005-11-01

Ascorbic acid can interfere with methodologies involving redox reactions, while comprehensive studies on main chemistry analysers have not been reported. We therefore attempted to determine the interference of ascorbic acid with analytes on the Beckman Synchron LX20. Various concentrations of ascorbic acid were added to serum, and the serum analytes were measured on the LX20. With a serum ascorbic acid concentration of 12.0 mmol/L, the values for sodium, potassium, calcium and creatinine increased by 43%, 58%, 103% and 26%, respectively (Pascorbic acid concentration of 12.0 mmol/L, the values for chloride, total bilirubin and uric acid decreased by 33%, 62% and 83%, respectively (Pcholesterol, triglyceride, ammonia and lactate. There was no definite influence of ascorbic acid on analytical values for total CO(2), urea, glucose, phosphate, total protein, albumin, amylase, creatine kinase, creatine kinase-MB, aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, total iron, unbound iron-binding capacity or magnesium. Ascorbic acid causes a false increase in sodium, potassium, calcium and creatinine results and a false decrease in chloride, total bilirubin, uric acid, total cholesterol, triglyceride, ammonia and lactate results.

Effect of antioxidants and associate changes in antioxidant enzymes in controlling browning and necrosis of proliferating shoots of elite Jatropha curcas L

International Nuclear Information System (INIS)

Misra, Pratibha; Toppo, Dibya D.; Gupta, Neha; Chakrabarty, Debasis; Tuli, Rakesh

2010-01-01

A high yielding elite plant of Jatropha curcas was established under aseptic condition from field-grown nodal explants. Shoots were proliferated in MS medium supplemented with 0.5 mg dm -3 benzyladenine and 0.1 mg dm -3 indolebutyric acid along with 10 mg dm -3 adenine sulphate and a combination of 15 mg dm -3 each of L-glutamine and L-arginine. However, within 15-20 d of culture incubation, tissue browning/necrosis leading to poor plant regeneration in vitro was observed. A set of different antioxidants, namely, reduced glutathione, ascorbic acid, tocopherol and cysteine were used in the medium individually and in combination to solve the problem of tissue browning and necrosis. The addition of antioxidants proved beneficial for the growth of the shoots. The optimum medium comprised of 25 mg dm -3 reduced glutathione and 10 mg dm -3 ascorbic acid, where proliferating shoots having highest leaf canopy area, remained fresh, green and regenerative up to 40 d of culture incubation without any subculture. The activities of antioxidant enzymes, such as superoxide dismutase was higher in control shoots, indicating that tissue browning/necrosis was associated with oxidative stress which was further supported by higher contents of H 2 O 2 and phenolics in control shoots compared to the other treatments. Similarly glutathione reductase, ascorbate peroxidase and guiacol peroxidase was higher in treated shoots than control indicating that these shoots have developed antioxidant enzymatic protective system which determine the ability to survive in oxidative stress and up regulation of these enzymes would help to reduce the built up of reactive oxygen species.

Influence of natural and synthetic vitamin C (ascorbic acid) on primary and secondary metabolites and associated metabolism in quinoa (Chenopodium quinoa Willd.) plants under water deficit regimes.

Science.gov (United States)

Aziz, Aniqa; Akram, Nudrat Aisha; Ashraf, Muhammad

2018-02-01

Phytoextracts are being widely used these days as a source of bioactive compounds for mitigating the harmful effects of abiotic stresses including drought stress. In this study, it was assessed how far foliar applied pure synthetic ascorbic acid (AsA) or natural sweet orange juice (OJ) enriched with AsA could mitigate the drought stress induced adverse effects on growth and some key metabolic processes in quinoa (Chenopodium quinoa Willd.; cultivar V 9 ) plants. Two weeks old quinoa seedlings were subjected to varying irrigation regimes as control [100% field capacity (FC)] and drought stress (60% FC, 40% FC and 20% FC). After one month of water deficit treatments, various levels of ascorbic acid (150 mg L -1 AsA or 25% OJ) besides control [distilled water (DW) and no spray (NS)] were applied as a foliar spray. After 15 days of AsA application, different physio-biochemical attributes were measured. The results showed that water deficit markedly decreased plant growth, relative water content (RWC), photosynthetic rate, total carotenoids (CAR) and total flavonoids, while it increased relative membrane permeability (RMP), intrinsic AsA content, hydrogen peroxide (H 2 O 2 ), malondialdehyde (MDA), glycinebetaine (GB), total phenolics, total soluble proteins (TSP), total free amino acids, activities of key antioxidant enzymes [superoxide dismutase (SOD), peroxidase (POD)], total soluble sugars (TSS), reducing (RS) and non-reducing sugars (NRS). Most obvious results of most of these parameters were observed at 40% and 20% FC. Foliar-applied pure 150 mg L -1 AsA and 25% OJ were found to be very effective in improving plant growth, RMP, photosynthetic rate, CAR, proline, AsA, MDA, GB, TSP, free amino acids, SOD, POD, TSS, RS, NRS and total flavonoids. It was noticed that 25% OJ enriched with AsA and other essential nutrients and biomolecules was as efficient as 150 mg L -1 AsA in reducing the adverse effects of drought stress on quinoa plants. So, it was concluded

Dietary ascorbic acid modulates the expression profile of stress protein genes in hepatopancreas of adult Pacific abalone Haliotis discus hannai Ino.

Science.gov (United States)

Wu, Chenglong; Wang, Jia; Xu, Wei; Zhang, Wenbing; Mai, Kangsen

2014-12-01

This study was conducted to investigate the effects of dietary ascorbic acid (AA) on transcriptional expression patterns of antioxidant proteins, heat shock proteins (HSP) and nuclear factor kappa B (NF-κB) in the hepatopancreas of Pacific abalone Haliotis discus hannai Ino (initial average length: 84.36 ± 0.24 mm) using real-time quantitative PCR assays. L-ascorbyl-2-molyphosphate (LAMP) was added to the basal diet to formulate four experimental diets containing 0.0, 70.3, 829.8 and 4967.5 mg AA equivalent kg(-1) diets, respectively. Each diet was fed to triplicate groups of adult abalone in acrylic tanks (200 L) in a flow-through seawater system. Each tank was stocked with 15 abalone. Animals were fed once daily (17:00) to apparent satiation for 24 weeks. The results showed that the dietary AA (70.3 mg kg(-1)) could significantly up-regulate the expression levels of Cu/Zn superoxide dismutase (SOD), catalase (CAT), glutathione-S-transferase (GST), feritin (FT) and heat shock protein 26 (HSP26) in the hepatopancreas of abalone in this treatment compared to the controls. However, the expression levels of Mn-SOD, glutathione peroxidase (GPX), thioredoxin peroxidase (TPx), selenium-binding protein (SEBP), HSP70 and HSP90 were significantly down-regulated. Compared with those in the group with 70.3 mg kg(-1) dietary AA, the expression levels of CAT, GST and HSP26 were decreased in abalone fed with very high dietary AA (4967.5 mg kg(-1)). In addition, significant up-regulations of expression levels of Mn-SOD, GPX, TPx, SEBP, FT, HSP70, HSP90 and NF-κB were observed in abalone fed with apparently excessive dietary AA (829.8 and 4967.5 mg kg(-1)) as compared to those fed 70.3 mg kg(-1) dietary AA. These findings showed that dietary AA influenced the expression levels of antioxidant proteins, heat shock proteins and NF-κB in the hepatopancreas of abalone at transcriptional level. Levels of dietary AA that appeared adequate (70.3 mg kg(-1)) reduced the oxidative stress

The Effect of Water Deficit Different Levels on Antioxidant System and Lipid Peroxidation in two Species Tagetes erecta and Tagetes patula of Marigold

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seyyed mousa mousavi

2018-02-01

Full Text Available Introduction: With regard to decrease of precipitation and poor distribution of rainfall during the dry phenomenon of urban, green spaces face problems. In fact, one of the most important environmental stress is drought stress at different stages of plant growth such as seed germination, seedling establishment and crop production. The effect of drought stress, plants photochemical activity ceased Calvin cycle enzymes and chlorophyll content also varies in the process of photosynthesis under drought stress. Under drought stress, reactive oxygen species (ROS such as hydrogen peroxide (H2O2, superoxide radicals (O2 • - and hydroxide (OH • increase their accumulation in cells that can lead to oxidative stress. To neutralize ROS, antioxidant enzymes systems in plant such as superoxide dismutase (SOD, peroxidase (POD, catalase (CAT and ascorbate peroxidase (APX are active. The response of antioxidants depends on the lack of water, the intensity of the stress and the type of plant species. Also, it is well known that photosynthetic systems in higher plants are most sensitive to drought stress. Indeed, drought is one of the factors affecting photosynthesis and chlorophyll content. Some of researchers reported that chlorophyll might estimate influence of environmental stress on growth because these parameters were closely correlated with the rate of carbon exchange. The aim of this study was an investigation of effect of water deficit different levels on antioxidant system and lipid peroxidation in two species of marigold. Therefore, an experiment was carried out as factorial in a randomized complete block design with three replication at Shahid Chamran University of Ahvaz in 2014 year. Materials and methods: Experimental treatments were irrigation with three levels: 100% ETcrop (no stress, 75% ETcrop (moderate stress and 50% ETcrop (severe stress and two species of marigold (African and French. Catalase activity decreased absorption at a wavelength

Peroxidase activity as a marker for estrogenicity

International Nuclear Information System (INIS)

Levy, J.; Liel, Y.; Glick, S.M.

1981-01-01

We examined the possibility that peroxidase activity might be a marker for estrogen activity in established estrogen-dependent tissues: dimethylbenz[a]anthracene (DMBA)-induced rat mammary tumours and human breast cancer. In DMBA-induced tumours undergoing regression after ovariectomy or tamoxifen treatment, tumour size decreased by 50%, estradiol receptors (ER) and progesterone receptors (PgR) decreased by 25 and 20%, respectively, but peroxidase activity paradoxically increased six- to sevenfold. In DMBA tumours stimulated by estradiol treatment or by the cessation of tamoxifen administration in intact rats, tumour size increased threefold. ER and PgR increased two- and threefold, respectively, while peroxidase activity decreased 50%. These data indicate an inverse relation between tumour growth, ER and PgR on the one hand, and peroxidase activity on the other. In the human breast cancers there was a singificant negative relation between the presence of ER and peroxidase activity. By using a calibrated Sephadex G-100 column it was shown that uterine peroxidase differs in molecular weight from the peroxidase of rat mammary tumours and that of human breast cancer. (author)

Stimulation of matrix formation in rabbit chondrocyte cultures by ascorbate. 1. Effect of ascorbate analogs and beta-aminopropionitrile.

Science.gov (United States)

Wright, G C; Wei, X Q; McDevitt, C A; Lane, B P; Sokoloff, L

1988-01-01

The most consistent effects of 0.2 mM L-ascorbate on monolayer cultures of rabbit articular chondrocytes were a diversion of incorporated radiosulfate into a pericellular matrix and enhancement of cell proliferation. Only with certain batches of fetal bovine serum (FBS) was there a cell-for-cell increase of proteoglycan synthesis. These actions increased as the cell inoculum rose from 0.5 to 2 x 10(5) cells/T25 flask. Maximal effects of ascorbate and D-isoascorbate were found over a range of 0.05-0.2 mM. L-Dehydroascorbic acid was less effective than either, and no stimulatory action was exerted by L-cysteine, glutathione, dithiothreitol, methylene blue, or phenazine methosulfate. Ascorbate increased the hypro:pro ratio of newly synthesized proteins. beta-Aminopropionitrile (1 mM) reduced the proportion of [3H]hydroxyproline and [35S]O4-proteoglycans in the ascorbate-supplemented matrix 31 and 7%, respectively. In corresponding electronmicrographs, the number of pericellular filaments was reduced. We conclude: (a) Ascorbate has a general anabolic effect on chondrocytes in culture and enhances matrix assembly through mechanisms other than its redox function; (b) deposition of proteoglycans in the matrix is not simply the result of mechanical entrapment by allysine- or hydroxyallysine-derived cross-linking of collagen; and (c) contradictory reports on the subject result from variations in the serum employed, inoculum density, and concentration of ascorbate.

Oxidation of NAD dimers by horseradish peroxidase.

OpenAIRE

Avigliano, L; Carelli, V; Casini, A; Finazzi-Agrò, A; Liberatore, F

1985-01-01

Horseradish peroxidase catalyses the oxidation of NAD dimers, (NAD)2, to NAD+ in accordance with a reaction that is pH-dependent and requires 1 mol of O2 per 2 mol of (NAD)2. Horseradish peroxidase also catalyses the peroxidation of (NAD)2 to NAD+. In contrast, bacterial NADH peroxidase does not catalyse the peroxidation or the oxidation of (NAD)2. A free-radical mechanism is proposed for both horseradish-peroxidase-catalysed oxidation and peroxidation of (NAD)2.

Implications of mycosporine-like amino acid and antioxidant defenses in UV-B radiation tolerance for the algae species Ptercladiella capillacea and Gelidium amansii.

Science.gov (United States)

Lee, Tse-Min; Shiu, Chia-Tai

2009-02-01

Ultraviolet-B (UV-B) radiation (0.5, 1.0, 1.5, and 3.0Wm(-2)) induced higher H(2)O(2) production and lipid peroxidation in alga Gelidium amansii inhabiting in lower subtidal regions than upper subtidal alga Ptercladiella capillacea. Compared to G. amansii, mycosporine-like amino acid (MAA) concentration in P. capillacea was higher and can be increased by 0.5-1.0Wm(-2) UV-B, while carotenoid concentration was lower but also increased by 1.5-3.0Wm(-2) UV-B. UV-B increased ascorbate concentration, but to a higher degree in P. capillacea. UV-B decreased glutathione concentration, but to a higher degree in G. amansii. UV-B increased ascorbate peroxidase (APX) and glutathione reductase (GR) activities in P.capillacea but decreased them in G. amansii. UV-B increased superoxide dismutase and catalase activities, but to a higher degree in G. amansii. So, G. amansii suffered greater oxidative stress from UV-B radiation. P. capillacea can effectively reduce UV-B sensitivity by increasing sunscreen ability and antioxidant defense capacity.

Antioxidant Defenses in Plants with Attention to Prunus and Citrus spp.

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Milvia Luisa Racchi

2013-11-01

Full Text Available This short review briefly introduces the formation of reactive oxygen species (ROS as by-products of oxidation/reduction (redox reactions, and the ways in which the antioxidant defense machinery is involved directly or indirectly in ROS scavenging. Major antioxidants, both enzymatic and non enzymatic, that protect higher plant cells from oxidative stress damage are described. Biochemical and molecular features of the antioxidant enzymes superoxide dismutase (SOD, catalase (CAT, and ascorbate peroxidase (APX are discussed because they play crucial roles in scavenging ROS in the different cell compartments and in response to stress conditions. Among the non enzymatic defenses, particular attention is paid to ascorbic acid, glutathione, flavonoids, carotenoids, and tocopherols. The operation of ROS scavenging systems during the seasonal cycle and specific developmental events, such as fruit ripening and senescence, are discussed in relation to the intense ROS formation during these processes that impact fruit quality. Particular attention is paid to Prunus and Citrus species because of the nutritional and antioxidant properties contained in these commonly consumed fruits.

Ascorbate regulates haematopoietic stem cell function and leukaemogenesis.

Science.gov (United States)

Agathocleous, Michalis; Meacham, Corbin E; Burgess, Rebecca J; Piskounova, Elena; Zhao, Zhiyu; Crane, Genevieve M; Cowin, Brianna L; Bruner, Emily; Murphy, Malea M; Chen, Weina; Spangrude, Gerald J; Hu, Zeping; DeBerardinis, Ralph J; Morrison, Sean J

2017-09-28

Stem-cell fate can be influenced by metabolite levels in culture, but it is not known whether physiological variations in metabolite levels in normal tissues regulate stem-cell function in vivo. Here we describe a metabolomics method for the analysis of rare cell populations isolated directly from tissues and use it to compare mouse haematopoietic stem cells (HSCs) to restricted haematopoietic progenitors. Each haematopoietic cell type had a distinct metabolic signature. Human and mouse HSCs had unusually high levels of ascorbate, which decreased with differentiation. Systemic ascorbate depletion in mice increased HSC frequency and function, in part by reducing the function of Tet2, a dioxygenase tumour suppressor. Ascorbate depletion cooperated with Flt3 internal tandem duplication (Flt3 ITD ) leukaemic mutations to accelerate leukaemogenesis, through cell-autonomous and possibly non-cell-autonomous mechanisms, in a manner that was reversed by dietary ascorbate. Ascorbate acted cell-autonomously to negatively regulate HSC function and myelopoiesis through Tet2-dependent and Tet2-independent mechanisms. Ascorbate therefore accumulates within HSCs to promote Tet activity in vivo, limiting HSC frequency and suppressing leukaemogenesis.

"Chitin-specific" peroxidases in plants.

Science.gov (United States)

Maksimov, I V; Cherepanova, E A; Khairullin, R M

2003-01-01

The activity of various plant peroxidases and the ability of their individual isoforms to bind chitin was studied. Some increase in peroxidase activity was observed in crude extracts in the presence of chitin. Activated peroxidases of some species fell in the fraction not sorbed on chitin and those of other species can bind chitin. Only anionic isoperoxidases from oat (Avena sativa), rice (Oryza sativa), horseradish (Armoracia rusticana), garden radish (Raphanus sativus var. radicula), peanut (Arachis hypogaea), and tobacco (Nicotiana tabacum Link et Otto) were sorbed on chitin. Both anionic and cationic isoforms from pea (Pisum sativum), galega(Galega orientalis), cucumber (Cucumis sativus), and zucchini (Cucurbita pepo L.) were sorbed on chitin. Peroxidase activation under the influence of chitin was correlated to the processes that occur during hypersensitive reaction and lignification of sites, in which pathogenic fungus penetrates into a plant. The role of chitin-specific isoperoxidases in inhibition of fungal growth and connection of this phenomenon with structural characteristics of isoperoxidases are also discussed.

Uso do ácido ascórbico no controle do escurecimento do pericarpo de lichia Use of ascorbic acid in the control of browning in the pericarp of lychees

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Danieele Fabíola Pereira da Silva

2010-06-01

Full Text Available Um dos maiores problemas na pós-colheita da lichia é o escurecimento do pericarpo, o qual tem sido atribuído à degradação da antocianina. O objetivo do trabalho foi avaliar o efeito de diferentes doses de ácido ascórbico na prevenção do escurecimento do pericarpo e na manutenção da qualidade pós-colheita de lichia. Frutos de lichieira 'Bengal' com o pericarpo completamente vermelho foram imersos em solução com diferentes doses de ácido ascórbico (0; 5; 10; 15 e 30 mM, por 5 minutos. Após secagem à temperatura ambiente, foram acondicionados em bandejas de poliestireno, armazenados em câmara fria a 5 ± 1,2°C e 90 ± 5% de UR e avaliados a cada 4 dias, durante 12 dias. Observou-se que a perda de massa fresca foi maior nos frutos não tratados com ácido ascórbico. Independentemente da dose, o ácido ascórbico teve pouco efeito na retenção da cor vermelha do pericarpo de lichia. A atividade das enzimas polifenoloxidase e peroxidase no pericarpo foi maior com as menores doses de ácido ascórbico (0; 5 e 10 mM, entretanto observou-se escurecimento a partir do quarto dia no pericarpo dos frutos tratados com este ácido. O ácido ascórbico também não foi eficiente na manutenção da qualidade interna dos frutos.One of the biggest problems in postharvest of lychees is the pericarp browning, which has been attributed to anthocyanins degradation. The purpose of this work was to evaluate the effect of different doses of ascorbic acid to prevent pericarp browning and on the maintenance of postharvest quality of lychees. Fruits of 'Bengal' lychee with completely red pericarp were immersed in solution with different doses of ascorbic acid (0, 5, 10, 15 and 30 mM for 5 minutes. After dried, the fruits were packed in polystyrene trays, stored in cold chamber at 5 ± 1,2°C e 90 ± 5% de RH and evaluated every other 4 days for 12 days. It was observed that the loss of fresh weight was higher in non-treated with ascorbic acid

Role of vitamin C and E supplementation on IL-6 in response to training

DEFF Research Database (Denmark)

Yfanti, Christina; Fischer, Christian P.; Nielsen, Søren

2012-01-01

, including catalase, copper-zinc superoxide dismutase, and glutathione peroxidase 1 mRNA expression in the VT group. However, skeletal muscle protein content of catalase, copper-zinc superoxide dismutase, or glutathione peroxidase 1 was not affected by training or supplementation. In conclusion, our results...

sup(99)Tcsup(m)-ascorbate

International Nuclear Information System (INIS)

Persson, R.B.R.; Strand, S.E.; White, T.

1975-01-01

The sup(99)Tcsup(m)-ascorbate preparation used in this investigation contained FeCl 3 4mN, asorbic acid 110 mM and had an initial pH-value of 7.4 and a final pH-value of 6.8. Studies of the complex-formation were performed with gel-chromatography column-scanning (GCS), which is the analytical method to be preferred for this type of compound, indicated that the complex was formed in two steps. First reduced hydrolyzed sup(99)Tcsup(m) was formed rapidly and the sup(99)Tcsup(m)-ascorbate was formed by a slower reaction (k = 3, 10 -2 min -1 ). The renal uptake of sup(99)Tcsup(m)- was studied in 29 patients with a gamma-camera. The time-course of radio-activity in kidneys, 'tissue background'-areas and in blood suggested that optimal conditions for kidney-imaging were reached 3 to 6 hr after injection. About 20% of the sup(99)Tcsup(m)-ascorbate was bound to plasma-proteins, and only a small fraction to red blood-cells. The disappearance of the sup(99)Tcsup(m)-ascorbate from plasma followed a three-exponential curve: 40% with a half-life of 0.2 hr, 30% with a half-life of 20 hr. The absorbed radiation dose to the kidneys was about 200 (SE +- 60) mrad mCi -1 and to the whole-body 10 (SE +- 3) mrad mCi -1 of administered activity. There was a close correlation (r + 0.98) of the separate renal uptake (dx:(dx +sin)) of sup(99)Tcsup(m)-ascorbate to the separate renal function as determined with 131 I-Hippuran. (author)

Structure of soybean seed coat peroxidase: a plant peroxidase with unusual stability and haem-apoprotein interactions

DEFF Research Database (Denmark)

Henriksen, A; Mirza, O; Indiani, C

2001-01-01

Soybean seed coat peroxidase (SBP) is a peroxidase with extraordinary stability and catalytic properties. It belongs to the family of class III plant peroxidases that can oxidize a wide variety of organic and inorganic substrates using hydrogen peroxide. Because the plant enzyme is a heterogeneous...... glycoprotein, SBP was produced recombinant in Escherichia coli for the present crystallographic study. The three-dimensional structure of SBP shows a bound tris(hydroxymethyl)aminomethane molecule (TRIS). This TRIS molecule has hydrogen bonds to active site residues corresponding to the residues that interact...... with the small phenolic substrate ferulic acid in the horseradish peroxidase C (HRPC):ferulic acid complex. TRIS is positioned in what has been described as a secondary substrate-binding site in HRPC, and the structure of the SBP:TRIS complex indicates that this secondary substrate-binding site could...

21 CFR 182.3013 - Ascorbic acid.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Ascorbic acid. 182.3013 Section 182.3013 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN... acid. (a) Product. Ascorbic acid. (b) Conditions of use. This substance is generally recognized as safe...

Effects of 60Co γ-rays irradiation on seed growth of ground-cover chrysanthemum

International Nuclear Information System (INIS)

Ge Weiya; Wang Tiantian; Yang Shuhua; Zhao Ying; Ge Hong; Chen Lin

2011-01-01

The seeds of ground-cover chrysanthemum were used to study the effects of different doses of 60 Co γ-rays irradiation(10-50 Gy) on seed germination and physiological characteristics. The results showed that the rate of seed germination and seedling survival decreased significantly with the irradiation doses. With the increase of irradiation dose to above 20 Gy, the content of malondialdehyde (MDA) and activity of peroxidase (POD) in seedlings significantly increased. The similar trends were found in the activities of superoxide dismutase (SOD) and glutathione reductase (GR). Catalase (CAT) activity increased at doses lower than 20 Gy, and then decreased at the higher doses, whereas ascorbate peroxidase (APX) activity did not alter except for 40 Gy. It is concluded that the suitable irradiation dose of mutation breeding is 20 Gy for the seeds of ground-cover chrysanthemum. Although 60 Co γ-rays irradiation resulted in damage of membrane lipid peroxidation in the survival seedlings, the increased activity of CAT and POD could protect them against the damage. (authors)

Antioxidant-enzyme reaction to the oxidative stress due to alpha-cypermethrin, chlorpyriphos, and pirimicarb in tomato (Lycopersicon esculentum Mill.).

Science.gov (United States)

Chahid, Karim; Laglaoui, Amin; Zantar, Said; Ennabili, Abdeslam

2015-11-01

Tomato (Lycopersicon esculentum Mill.) becomes one of the world's foremost vegetables, and its world production and consumption have increased fairly quickly. The capacity to induce oxidative stress in tomato plant, exposed to three xenobiotics such as alpha-cypermethrin, chlorpyriphos, and pirimicarb, was investigated by the evaluation of lipid peroxidation by measuring malondialdehyde (MDA) rate; also, we studied the response of tomato to this stress by assessing the response of superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), ascorbate peroxidase (APX), glutathione-s-transferase (GST), and glutathione reductase (GR). The effect of the insecticides was observed using four concentrations (25, 50, 75, and 100%) for germinating seeds and only the recommended concentration in agriculture (100%) for growing plants. Our results show an important accumulation of MDA, demonstrating the increase of lipid peroxidation in consequence of the excessive reactive oxygen species (ROS) production due to insecticide treatment. In response to this oxidative stress in tomato seedlings and plants, the activities of antioxidant-enzyme system were generally enhanced. The electrophoretic analysis showed also the apparition of new isoenzymes as the case for CAT and POD.

Investigation of arsenic accumulation and biochemical response of in vitro developed Vetiveria zizanoides plants.

Science.gov (United States)

Singh, Shraddha; Sounderajan, Suvarna; Kumar, Kiran; Fulzele, D P

2017-11-01

Vetiver grass (Vetiveria zizanoides L. Nash) is found to be a suitable candidate for the phytoremediation of heavy metals. An investigation of arsenic (As) accumulation, translocation and tolerance was conducted in V. zizanoides plantlets upon exposure to different concentrations of arsenic (10, 50, 100 and 200µM) for 7 and 14 d. V. zizanoides plants were found effective in remediation of As, maximum being at 200µM after 14 d of exposure. The results of TBARS and photosynthetic pigments demonstrated that plants did not experience significant toxicity at all the concentrations of As after 7 days, however an increase in their level was found after 14 d. The up-regulation of antioxidant enzyme activities of superoxide dismutase (SOD), ascorbate peroxidase (APX), guaiacol peroxidase (GPX), catalase (CAT) and glutathione s-transferase (GST) in a coordinated and complementary manner enhanced tolerance to plants against arsenic induced oxidative stress. Taken together, the results indicated that in vitro developed plants of V. zizanoides have the potential to remediate and tolerate varying levels of As. Copyright © 2017 Elsevier Inc. All rights reserved.

Alleviation of adverse impact of salt in Phaseolus vulgaris L. by arbuscular mycorrhizal fungi

International Nuclear Information System (INIS)

Allah, E.F.; Alqarawi, A.A.

2015-01-01

The present study was undertaken to evaluate the possible role of arbuscular mycorrhizal fungi (AMF) in enhancing the salt (0, 0.15; 0.25 M NaCl) tolerance in Phaselous vulgaris. The impact of AMF in presence and absence of salt stress was studied on growth, nodulation, and attributes of systemic acquired resistance in P. vulgaris. The results suggested that salinity caused significant decrease in growth performance, nodulation, pigment system, tissue water content, and membrane stability index. Also, salt stress caused significant decrease in phytohormones , polyamines, membrane stability index and tissue water content of P. vulgaris. On the other hand, lipid peroxidation (malondialdehyde), total phenol content and antioxidant enzymes (catalase, peroxidase, superoxide dismutase, ascorbate peroxidase, glutathione reductase) increases as salt concentration increases. The accumulations of sodium, chlorine were significantly increased by salt stress, however the concentration of potassium, phosphorous and calcium decreased. Overall, the results indicate that AMF alleviate the adverse impact of salinity on the plant growth, anabolic physiological attributes and nutrient uptake by reducing the oxidative damage of salt through strengthening and modulation the systemic acquired resistance. (author)

Biochemical changes in hybrid pumpkin seeds at different stages of maturation

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Patrícia Pereira da Silva

Full Text Available ABSTRACT This study aimed to evaluate biochemical changes in seeds of the pumpkin hybrid, 'Jabras', from fruit harvested at different stages of maturation (15, 30, 45, 60 and 75 days after anthesis. Thirty fruit were harvested at each stage, with the seeds from 15 of the fruit being extracted immediately. The remaining 15 were stored for twenty days in plastic boxes and the seeds extracted after this period. After processing and drying the seeds, the following were determined: moisture content, germination, first count and antioxidant enzyme activity (peroxidase, ascorbate peroxidase, catalase and superoxide dismutase. Seeds from the fruit harvested at 30 DAA displayed low values for germination and vigour and high antioxidant enzyme activity, indicating that they were immature and that drying possibly caused damage to the system of cell membranes. The results obtained in this study demonstrated that analysis related to changes in the activity of enzymes during development and maturation of the seeds was effective in evaluating the physiological and biochemical changes in pumpkin seeds of the 'Jabras' cultivar.

The effect of kinetin on wheat seedlings exposed to boron.

Science.gov (United States)

Eser, Ahmet; Aydemir, Tülin

2016-11-01

The objective of this study was to examine relationship between boron (B) induced oxidative stress and antioxidant system in boron sensitive and tolerant wheat cultivars Bezostaya and Kutluk, and also to investigate whether Kinetin (KN) enhances the level of antioxidant system, relative growth, concentration of hydrogen peroxide (H 2 O 2 ), malondialdehyde (MDA) and proline and chlorophyll content in both cultivars exposed to B stress. B treatments diminished growth and chlorophyll content whereas, it enhanced accumulation of H 2 O 2 , MDA and proline, and various antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), guaiacol peroxidase (GPX) and lipoxygenase (LOX) in the shoot and root of both cultivars. However, the follow-up application of KN to the B stressed plants improved growth and chlorophyll content and further enhanced the mentioned antioxidant enzymes and level of H 2 O 2 , MDA and proline. This study thus suggests that KN improves B tolerance of the studied cultivars grown under B toxicity. Copyright © 2016. Published by Elsevier Masson SAS.

Mercury-induced biochemical and proteomic changes in rice roots.

Science.gov (United States)

Chen, Yun-An; Chi, Wen-Chang; Huang, Tsai-Lien; Lin, Chung-Yi; Quynh Nguyeh, Thi Thuy; Hsiung, Yu-Chywan; Chia, Li-Chiao; Huang, Hao-Jen

2012-06-01

Mercury (Hg) is a serious environmental pollution threats to the planet. Accumulation of Hg in plants disrupts many cellular-level functions and inhibits growth and development, but the mechanism is not fully understood. We investigated cellular, biochemical and proteomic changes in rice roots under Hg stress. Root growth rate was decreased and Hg, reactive oxygen species (ROS), and malondialdehyde (MDA) content and lipoxygenase activity were increased significantly with increasing Hg concentration in roots. We revealed a time-dependent alteration in total glutathione content and enzymatic activity of superoxide dismutase (SOD), ascorbate peroxidase (APX), catalase (CAT) and peroxidase (POD) during Hg stress. 2-D electrophoresis revealed differential expression of 25 spots with Hg treatment of roots: 14 spots were upregulated and 11 spots downregulated. These differentially expressed proteins were identified by ESI-MS/MS to be involved in cellular functions including redox and hormone homeostasis, chaperone activity, metabolism, and transcription regulation. These results may provide new insights into the molecular basis of the Hg stress response in plants. Copyright © 2012 Elsevier Masson SAS. All rights reserved.

Ascorbic acid transport and accumulation in human neutrophils

International Nuclear Information System (INIS)

Washko, P.; Rotrosen, D.; Levine, M.

1989-01-01

The transport, accumulation, and distribution of ascorbic acid were investigated in isolated human neutrophils utilizing a new ascorbic acid assay, which combined the techniques of high performance liquid chromatography and coulometric electrochemical detection. Freshly isolated human neutrophils contained 1.0-1.4 mM ascorbic acid, which was localized greater than or equal to 94% to the cytosol, was not protein bound, and was present only as ascorbic acid and not as dehydroascorbic acid. Upon addition of ascorbic acid to the extracellular medium in physiologic amounts, ascorbic acid was accumulated in neutrophils in millimolar concentrations. Accumulation was mediated by a high affinity and a low affinity transporter; both transporters were responsible for maintenance of concentration gradients as large as 50-fold. The high affinity transporter had an apparent Km of 2-5 microns by Lineweaver-Burk and Eadie-Hofstee analyses, and the low affinity transporter had an apparent Km of 6-7 mM by similar analyses. Each transporter was saturable and temperature dependent. In normal human blood the high affinity transporter should be saturated, whereas the low affinity transporter should be in its linear phase of uptake

Tetra(p-tolyl)borate-functionalized solvent polymeric membrane: a facile and sensitive sensing platform for peroxidase and peroxidase mimetics.

Science.gov (United States)

Wang, Xuewei; Qin, Wei

2013-07-22

The determination of peroxidase activities is the basis for enzyme-labeled bioaffinity assays, peroxidase-mimicking DNAzymes- and nanoparticles-based assays, and characterization of the catalytic functions of peroxidase mimetics. Here, a facile, sensitive, and cost-effective solvent polymeric membrane-based peroxidase detection platform is described that utilizes reaction intermediates with different pKa values from those of substrates and final products. Several key but long-debated intermediates in the peroxidative oxidation of o-phenylenediamine (o-PD) have been identified and their charge states have been estimated. By using a solvent polymeric membrane functionalized by an appropriate substituted tetraphenylborate as a receptor, those cationic intermediates could be transferred into the membrane from the aqueous phase to induce a large cationic potential response. Thus, the potentiometric indication of the o-PD oxidation catalyzed by peroxidase or its mimetics can be fulfilled. Horseradish peroxidase has been detected with a detection limit at least two orders of magnitude lower than those obtained by spectrophotometric techniques and traditional membrane-based methods. As an example of peroxidase mimetics, G-quadruplex DNAzymes were probed by the intermediate-sensitive membrane and a label-free thrombin detection protocol was developed based on the catalytic activity of the thrombin-binding G-quadruplex aptamer. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Suppression of radiation-induced in vitro carcinogenesis by ascorbic acid

International Nuclear Information System (INIS)

Tauchi, Hiroshi; Sawada, Shozo

1993-01-01

The effects of ascorbic acid on radiation-induced in vitro carcinogenesis have been reported using neoplastic transformation system of C3H 10T1/2 cells. In these reports, no suppressive effect on X-ray-induced transformation was observed with 6 weeks' administration of ascorbic acid (daily addition for 5 days per week) by Kennedy (1984), whereas apparent suppression was observed with daily addition for 7 days by Yasukawa et al (1989). We have tested the effects of ascorbic acid on 60 Co gamma-ray or 252 Cf fission neutron-induced transformation in Balb/c 3T3 cells. The transformation induced by both types of radiations was markedly suppressed when ascorbic acid was daily added to the medium during first 8 days of the post-irradiation period. If ascorbic acid was added for a total of 8 days but with a day's interruption in the middle, the suppression of transformation was decreased. These results suggest that continuous presence of ascorbic acid for a certain number of days is needed to suppress radiation-induced transformation. Since ascorbic acid also suppressed the promotion of radiation-induced transformation by TPA when both chemicals were added together into the medium, ascorbic acid might act on the promotion stage of transformation. Therefore, the effect of ascorbic acid on the distribution of protein kinase C activity was also investigated, and possible mechanisms of suppression of radiation-induced transformation by ascorbic acid will be discussed. (author)

Arbuscular mycorrhizal association enhances drought tolerance potential of promising bioenergy grass (Saccharum arundinaceum retz.).

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Mirshad, P P; Puthur, Jos T

2016-07-01

The influence of arbuscular mycorrhizal fungi (AMF) (Glomus spp.) on some physiological and biochemical characteristics of bioenergy grass Saccharum arundinaceum subjected to drought stress was studied. The symbiotic association of Glomus spp. was established with S. arundinaceum, a potential bioenergy grass as evident from the increase in percentage of root infection and distribution frequency of vesicles when compared with non-arbuscular mycorrhizal plants. AMF-treated plants exhibited an enhanced accumulation of osmolytes such as sugars and proline and also increased protein content under drought. AMF association significantly increased the accumulation of non-enzymatic antioxidants like phenols, ascorbate and glutathione as well as enhanced the activities of antioxidant enzymes such as SOD (superoxide dismutase), APX (ascorbate peroxidase) and GPX (guaiacol peroxidase) resulting in reduced lipid peroxidation in S. arundinaceum. AMF symbiosis also ameliorated the drought-induced reduction of total chlorophyll content and activities of photosystem I and II. The maximum quantum efficiency of PS II (F v/F m) and potential photochemical efficiency (F v/F o) were higher in AMF plants as compared to non-AMF plants under drought stress. These results indicate that AMF association alleviate drought stress in S. arundinaceum by the accumulation of osmolytes and non-enzymatic antioxidants and enhanced activities of antioxidant enzymes, and hence, the photosynthetic efficiency is improved resulting in increased biomass production. AMF association with energy grasses also improves the acclimatization of S. arundinaceum for growing in marginal lands of drought-affected soils.

Involvement of abscisic acid in regulating antioxidative defense systems and IAA-oxidase activity and improving adventitious rooting in mung bean [Vigna radiata (L.) Wilczek] seedlings under cadmium stress.

Science.gov (United States)

Li, Shi-Weng; Leng, Yan; Feng, Lin; Zeng, Xiao-Ying

2014-01-01

In vitro experiments were conducted to investigate the effects of abscisic acid (ABA) and Cd on antioxidative defense systems and indole-3-acetic acid (IAA) oxidase during adventitious rooting in mung bean [Vigna radiata (L.) Wilczek] seedlings. The exogenous ABA significantly enhanced the number and fresh weight of the adventitious roots. CdCl2 strongly inhibited adventitious rooting. Pretreatment with 10 μM ABA clearly alleviated the inhibitory effect of Cd on rooting. ABA significantly reduced superoxide dismutase (SOD), ascorbate peroxidase (APX), peroxidase (POD), and catalase (CAT) activities, as well as the levels of glutathione (GSH) and ascorbic acid (ASA) during adventitious rooting. ABA strongly increased IAA-oxidase activity during the induction (0-12 h) and expression (after 48 h) phases and increased the phenols levels. Cd treatment significantly reduced the activities of SOD, APX, POD, and IAA oxidase, as well as GSH level. Cd strongly increased ASA levels. ABA pretreatment counteracted Cd-induced alterations of certain antioxidants and antioxidative enzymes, e.g., remarkably rescued APX and POD activities, reduced the elevated SOD and CAT activities and ASA levels, and recovered the reduced GSH levels, caused by Cd stress. Thus, the physiological effects of the combination of ABA and Cd treatments were opposite of those obtained with Cd treatment alone, suggesting that ABA involved in the regulation of antioxidative defense systems and the alleviation of wounding- and Cd-induced oxidative stress.

Shelf life of minimally processed pineapples treated with ascorbic and citric acids

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Lucimara Rogéria Antoniolli

2012-01-01

Full Text Available The purpose of this research was to determine the shelf life of minimally processed (MP 'Pérola' pineapples treated with ascorbic acid (AA and citric acid (CA based on physical, chemical, sensorial and microbiological attributes. Slices were dipped into drinking water (control or combined solutions of AA:CA (% (1.0:0.5 and 1.0:1.0 with sodium hypochlorite (NaClO 20 mg L-1 for 30 seconds. The samples were conditioned in polyethylene terephtalate packages and stored at 4±1 °C per 13 days. The low peroxidase activity in the slices treated with antioxidant combinations was related to low pH values observed in these samples. The treatments 1.0:0.5 and 1.0:1.0 (AA:CA, % favored maintenance of the initial a* values and avoided the pulp browning. The ascorbic acid increased more than double on the 2nd day in the treated slices. By the 4th day the CO2 values suggested a higher respiratory activity in the slices treated with anti-browning compounds. The antioxidant treatments did not produce detectable residual flavors in the MP pineapple. Regardless of microbiological safety during the 13 days of cold storage, the control slices can be kept by 6 days, afterwards the color and dehydration become strong enough to affect the appearance. On the other hand, MP 'Pérola' pineapples treated with 1.0:0.5 (AA:CA, % and NaClO (20 mg L-1 can be stored for 8 days at 4±1 ºC, which represents the extension of the shelf life in 2 days. After this period the overripe odor starts to develop.

The inter-relationship of ascorbate transport, metabolism and mitochondrial, plastidic respiration.

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Szarka, András; Bánhegyi, Gábor; Asard, Han

2013-09-20

Ascorbate, this multifaceted small molecular weight carbohydrate derivative, plays important roles in a range of cellular processes in plant cells, from the regulation of cell cycle, through cell expansion and senescence. Beyond these physiological functions, ascorbate has a critical role in responses to abiotic stresses, such as high light, high salinity, or drought. The biosynthesis, recycling, and intracellular transport are important elements of the balancing of ascorbate level to the always-changing conditions and demands. A bidirectional tight relationship was described between ascorbate biosynthesis and the mitochondrial electron transfer chain (mETC), since L-galactono-1,4-lactone dehydrogenase (GLDH), the enzyme catalyzing the ultimate step of ascorbate biosynthesis, uses oxidized cytochrome c as the only electron acceptor and has a role in the assembly of Complex I. A similar bidirectional relationship was revealed between the photosynthetic apparatus and ascorbate biosynthesis since the electron flux through the photosynthetic ETC affects the biosynthesis of ascorbate and the level of ascorbate could affect photosynthesis. The details of this regulatory network of photosynthetic electron transfer, respiratory electron transfer, and ascorbate biosynthesis are still not clear, as are the potential regulatory role and the regulation of intracellular ascorbate transport and fluxes. The elucidation of the role of ascorbate as an important element of the network of photosynthetic, respiratory ETC and tricarboxylic acid cycle will contribute to understanding plant cell responses to different stress conditions.

Ascorbic acid deficiency in patients with lichen planus.

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Nicolae, Ilinca; Mitran, Cristina Iulia; Mitran, Madalina Irina; Ene, Corina Daniela; Tampa, Mircea; Georgescu, Simona Roxana

2017-01-01

Recent studies have highlighted the role of oxidative stress in the pathogenesis of lichen planus (LP). In the present study, the interest of the authors is focused on the investigation of ascorbic acid status in patients with LP and identification of parameters that might influence the level of this vitamin. We analyzed the level of urinary ascorbic acid (reflectometric method) in 77 patients with LP (cutaneous LP (CLP)-49 cases; oral LP (OLP)-28 cases) and 50 control subjects. The evaluation of all participants included clinical examination and laboratory and imaging tests. Compared to the control group (19.82 mg/dl) the level of ascorbic acid was significantly lower both in patients with CLP (8.47 mg/dl, p = 0.001) and in those with OLP (8.04 mg/dl, p = 0.001). In patients with LP it was found that the deficiency of ascorbic acid increases with age (r = -0.318, p = 0.032). The urinary concentrations of ascorbic acid were significantly lower in patients with LP associated with infections compared to patients with LP without infections. The urinary ascorbic acid level may be a useful parameter in identifying patients with LP who are at risk of developing viral or bacterial infections.

Low brain ascorbic acid increases susceptibility to seizures in mouse models of decreased brain ascorbic acid transport and Alzheimer's disease.

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Warner, Timothy A; Kang, Jing-Qiong; Kennard, John A; Harrison, Fiona E

2015-02-01

Seizures are a known co-occurring symptom of Alzheimer's disease, and they can accelerate cognitive and neuropathological dysfunction. Sub-optimal vitamin C (ascorbic acid) deficiency, that is low levels that do not lead the sufferer to present with clinical signs of scurvy (e.g. lethargy, hemorrhage, hyperkeratosis), are easily obtainable with insufficient dietary intake, and may contribute to the oxidative stress environment of both Alzheimer's disease and epilepsy. The purpose of this study was to test whether mice that have diminished brain ascorbic acid in addition to carrying human Alzheimer's disease mutations in the amyloid precursor protein (APP) and presenilin 1 (PSEN1) genes, had altered electrical activity in the brain (electroencephalography; EEG), and were more susceptible to pharmacologically induced seizures. Brain ascorbic acid was decreased in APP/PSEN1 mice by crossing them with sodium vitamin C transporter 2 (SVCT2) heterozygous knockout mice. These mice have an approximately 30% decrease in brain ascorbic acid due to lower levels of SVCT2 that supplies the brain with ASC. SVCT2+/-APP/PSEN1 mice had decreased ascorbic acid and increased oxidative stress in brain, increased mortality, faster seizure onset latency following treatment with kainic acid (10 mg/kg i.p.), and more ictal events following pentylenetetrazol (50 mg/kg i.p.) treatment. Furthermore, we report the entirely novel phenomenon that ascorbic acid deficiency alone increased the severity of kainic acid- and pentylenetetrazol-induced seizures. These data suggest that avoiding ascorbic acid deficiency may be particularly important in populations at increased risk for epilepsy and seizures, such as Alzheimer's disease. Copyright © 2014 Elsevier B.V. All rights reserved.

Formation of an ascorbate-apatite composite layer on titanium

Energy Technology Data Exchange (ETDEWEB)

Ito, Atsuo [National Institute of Advanced Industrial Science and Technology (AIST), Institute for Human Science and Biomedical Engineering, Central 6, Higashi 1-1-1, Tsukuba, Ibaraki 305-8566 (Japan); Sogo, Yu [National Institute of Advanced Industrial Science and Technology (AIST), Institute for Human Science and Biomedical Engineering, Central 6, Higashi 1-1-1, Tsukuba, Ibaraki 305-8566 (Japan); Ebihara, Yuko [School of Science and Technology, Waseda University, 3-4-1 Okubo, Sinjuku-ku, Tokyo 169-8050 (Japan); Onoguchi, Masahiro [School of Science and Technology, Waseda University, 3-4-1 Okubo, Sinjuku-ku, Tokyo 169-8050 (Japan); Oyane, Ayako [National Institute of Advanced Industrial Science and Technology (AIST), Nanotechnology Research Institute, Central 4, Higashi 1-1-1, Tsukuba, Ibaraki 305-8562 (Japan); Ichinose, Noboru [School of Science and Technology, Waseda University, 3-4-1 Okubo, Sinjuku-ku, Tokyo 169-8050 (Japan)

2007-09-15

An ascorbate-apatite composite layer was successfully formed on NaOH- and heat-treated titanium by coprecipitating L-ascorbic acid phosphate and low-crystalline apatite in a supersaturated calcium phosphate solution at 37 {sup 0}C for 48 h. The supersaturated calcium phosphate solutions used have chemical compositions attainable by mixing infusion fluids officially approved for clinical use. The amount of immobilized L-ascorbic acid phosphate ranged from 1.0 to 2.3 {mu}g mm{sup -2}, which is most likely to be sufficient for the in vitro osteogenic differentiation of mesenchymal stem cells on titanium. Since ascorbate is important for the collagen synthesis and subsequent osteogenesis of mesenchymal stem cells, titanium coated with the ascorbate-apatite composite layer would be useful as a scaffold in bone tissue engineering and as a bone substitute.

Formation of an ascorbate-apatite composite layer on titanium

International Nuclear Information System (INIS)

Ito, Atsuo; Sogo, Yu; Ebihara, Yuko; Onoguchi, Masahiro; Oyane, Ayako; Ichinose, Noboru

2007-01-01

An ascorbate-apatite composite layer was successfully formed on NaOH- and heat-treated titanium by coprecipitating L-ascorbic acid phosphate and low-crystalline apatite in a supersaturated calcium phosphate solution at 37 0 C for 48 h. The supersaturated calcium phosphate solutions used have chemical compositions attainable by mixing infusion fluids officially approved for clinical use. The amount of immobilized L-ascorbic acid phosphate ranged from 1.0 to 2.3 μg mm -2 , which is most likely to be sufficient for the in vitro osteogenic differentiation of mesenchymal stem cells on titanium. Since ascorbate is important for the collagen synthesis and subsequent osteogenesis of mesenchymal stem cells, titanium coated with the ascorbate-apatite composite layer would be useful as a scaffold in bone tissue engineering and as a bone substitute

Unraveling uranium induced oxidative stress related responses in Arabidopsis thaliana seedlings. Part I: responses in the roots.

Science.gov (United States)

Vanhoudt, Nathalie; Vandenhove, Hildegarde; Horemans, Nele; Remans, Tony; Opdenakker, Kelly; Smeets, Karen; Bello, Daniel Martinez; Wannijn, Jean; Van Hees, May; Vangronsveld, Jaco; Cuypers, Ann

2011-06-01

When aiming to evaluate the environmental impact of uranium contamination, it is important to unravel the mechanisms by which plants respond to uranium stress. As oxidative stress seems an important modulator under other heavy metal stress, this study aimed to investigate oxidative stress related responses in Arabidopsis thaliana exposed to uranium concentrations ranging from 0.1 to 100 μM for 1, 3 and 7 days. Besides analyzing relevant reactive oxygen species-producing and -scavenging enzymes at protein and transcriptional level, the importance of the ascorbate-glutathione cycle under uranium stress was investigated. These results are reported separately for roots and leaves in two papers: Part I dealing with responses in the roots and Part II unraveling responses in the leaves and presenting general conclusions. Results of Part I indicate that oxidative stress related responses in the roots were only triggered following exposure to the highest uranium concentration of 100 μM. A fast oxidative burst was suggested based on the observed enhancement of lipoxygenase (LOX1) and respiratory burst oxydase homolog (RBOHD) transcript levels already after 1 day. The first line of defense was attributed to superoxide dismutase (SOD), also triggered from the first day. The enhanced SOD-capacity observed at protein level corresponded with an enhanced expression of iron SOD (FSD1) located in the plastids. For the detoxification of H(2)O(2), an early increase in catalase (CAT1) transcript levels was observed while peroxidase capacities were enhanced at the later stage of 3 days. Although the ascorbate peroxidase capacity and gene expression (APX1) increased, the ascorbate/dehydroascorbate redox balance was completely disrupted and shifted toward the oxidized form. This disrupted balance could not be inverted by the glutathione part of the cycle although the glutathione redox balance could be maintained. Copyright © 2011 Elsevier Ltd. All rights reserved.

Distribution of ascorbate-2-sulfate and distribution, half-life and turnover rates of [1-14C]ascorbic acid in rainbow trout

International Nuclear Information System (INIS)

Tucker, B.W.; Halver, J.E.

1984-01-01

Rainbow trout (250 g) were maintained at 15 degrees C for 3 months on a low ascorbic acid diet, given [1- 14 C]ascorbic acid by gavage, then fed the NAS/NRC requirement 12 times per week. Total urine, fecal water and branchial water were collected daily from five fish placed in metabolism chambers for four successive 5-day periods. Tissue samples were analyzed for 14 C, ascorbic acid (C1) and ascorbate-2-sulfate (C2). Excretion analysis indicated t1/2 . 42 days. After 20 days, the feeding schedule was changed to 3 times per week. Fish fed 14 C were sampled after 1, 2, 3 and 4 months. The half-life in each organ except brain was inversely proportional to the dietary level of ascorbate. Concentrations of C1 and C2 in the various tissues reflected dietary intake of vitamin C. Total C (CT . C1 + C2) levels were maintained in the liver even with the low vitamin C diet. Estimates of body pool for C1 are 27-29 mg/kg. At the higher ascorbate intake CT was 92-114 mg/kg, but decreased by 34% at the lower feeding rate to 51-62 mg/kg. Data indicate that there are two or more body pools that include a store of C2, which is readily interconverted in metabolizing tissues to and from C1. Since air and water stable C2 is antiscorbutic for fish, it is the preferred form of ascorbate for fish feeds

Interactive effects of silicon and arbuscular mycorrhiza in modulating ascorbate-glutathione cycle and antioxidant scavenging capacity in differentially salt-tolerant Cicer arietinum L. genotypes subjected to long-term salinity.

Science.gov (United States)

Garg, Neera; Bhandari, Purnima

2016-09-01

Salinity is the major environmental constraint that affects legume productivity by inducing oxidative stress. Individually, both silicon (Si) nutrition and mycorrhization have been reported to alleviate salt stress. However, the mechanisms adopted by both in mediating stress responses are poorly understood. Thus, pot trials were undertaken to evaluate comparative as well as interactive effects of Si and/or arbuscular mycorrhiza (AM) in alleviating NaCl toxicity in modulating oxidative stress and antioxidant defence mechanisms in two Cicer arietinum L. (chickpea) genotypes-HC 3 (salt-tolerant) and CSG 9505 (salt-sensitive). Plants subjected to different NaCl concentrations (0-100 mM) recorded a substantial increase in the rate of superoxide radical (O2 (·-)), H2O2, lipoxygenase (LOX) activity and malondialdehyde (MDA) content, which induced leakage of ions and disturbed Ca(2+)/Na(+) ratio in roots and leaves. Individually, Si and AM reduced oxidative burst by strengthening antioxidant enzymatic activities (superoxide dismutase (SOD), catalase (CAT) and guaiacol peroxidase (GPOX)). Si was relatively more efficient in reducing accumulation of stress metabolites, while mycorrhization significantly up-regulated antioxidant machinery and modulated ascorbate-glutathione (ASA-GSH) cycle. Combined applications of Si and AM complemented each other in reducing reactive oxygen species (ROS) build-up by further enhancing the antioxidant defence responses. Magnitude of ROS-mediated oxidative burden was lower in HC 3 which correlated strongly with more effective AM symbiosis, better capacity to accumulate Si and stronger defence response when compared with CSG 9505. Study indicated that Si and/or AM fungal amendments upgraded salt tolerance through a dynamic shift from oxidative destruction towards favourable antioxidant defence system in stressed chickpea plants.

Ascorbic Acid Contents in Chili Peppers (Capsicum L.

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Owk ANIEL KUMAR

2009-12-01

Full Text Available The genus Capsicum commonly known as chili pepper is a major spice crop and is almost cosmopolitan in distribution. The nutritive value of chili pepper is largely determined by ascorbic acid content. The fruits at five ripening stages viz., (M1, M2, M3, M4 and M5 from seventeen cultivars of Capsicum annuum L and one cultivar of Capsicum frutescens L were analyzed for ascorbic acid content. Among eighteen genotypes the C. annuum var. IC: 119262(CA2 showed higher ascorbic acid content (mg/100g FW i.e., 208.00.68 (M1, 231.00.66 (M2, 280.00.31 (M3, 253.00.34 (M4 and 173.70.27 (M5. The study revealed that the gradual increase in ascorbic acid content from green to red and subsequently declined in the lateral stages (red partially dried and red fully dried fruits. The variability of ascorbic acid content in the genotypes suggests that these selected genotypes may be use full as parents in hybridization programs to produce fruits with good nutritional values.

Fungal peroxidases : molecular aspects and applications

NARCIS (Netherlands)

Conesa, A.; Punt, P.J.; Hondel, C.A.M.J.J.

2002-01-01

Peroxidases are oxidoreductases that utilize hydrogen peroxide to catalyze oxidative reactions. A large number of peroxidases have been identified in fungal species and are being characterized at the molecular level. In this manuscript we review the current knowledge on the molecular aspects of this

Effect of antioxidant supplementation on lipid peroxidation and antioxidant enzyme activity on exposure to acute restraint stress in sprague dawley rats

International Nuclear Information System (INIS)

Lodhi, G.M.; Hussain, M.M.; Aslam, M.

2012-01-01

To determine the effects of ascorbic acid (AA) and alpha tocopherol (AT) supplementation on stress induced changes in serum malondialdehyde and serum superoxide dismutase levels in male Sprague Dawley rats. Study design: Quasi experimental study Place and Duration of Study: Department of Physiology, Army Medical College Rawalpindi in collaboration with National Institute of Health, Islamabad during March 2009 to September 2009. Materials and Methods: Eighty male Sprague Dawley rats were divided into five groups with sixteen rats in each group. Group I served as control without stress and group II exposed to restraint stress for 06 hours, group III given ascorbic acid, group IV alpha tocopherol and group V was supplemented with both vitamins along with standard diet for one month. All antioxidant supplemented groups were exposed to restraint stress for six hours. Immediately after stress, the blood samples were analyzed colorimetrically to estimate serum malondialdehyde and superoxide dismutase by commercially available kits. Results: There was no significant fall in serum malondialdehyde in rats supplemented with ascorbic acid alone, however rats supplemented with alpha tocopherol or combination of ascorbic acid and alpha tocopherol revealed significant fall in serum malondialdehyde and increment in superoxide dismutase activity. Conclusions: Alpha tocopherol alone and in combination with ascorbic acid is effective to prevent reactive oxygen species induced increase in lipid peroxidation and fall in super oxide dismutase activity thereby conferring protection against oxidative stress. (author)

Exogenous Spermidine Alleviates Low Temperature Injury in Mung Bean (Vigna radiata L. Seedlings by Modulating Ascorbate-Glutathione and Glyoxalase Pathway

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Kamrun Nahar

2015-12-01

Full Text Available The role of exogenous spermidine (Spd in alleviating low temperature (LT stress in mung bean (Vigna radiata L. cv. BARI Mung-3 seedlings has been investigated. Low temperature stress modulated the non-enzymatic and enzymatic components of ascorbate-glutathione (AsA-GSH cycle, increased H2O2 content and lipid peroxidation, which indicate oxidative damage of seedlings. Low temperature reduced the leaf relative water content (RWC and destroyed leaf chlorophyll, which inhibited seedlings growth. Exogenous pretreatment of Spd in LT-affected seedlings significantly increased the contents of non-enzymatic antioxidants of AsA-GSH cycle, which include AsA and GSH. Exogenous Spd decreased dehydroascorbate (DHA, increased AsA/DHA ratio, decreased glutathione disulfide (GSSG and increased GSH/GSSG ratio under LT stress. Activities of AsA-GSH cycle enzymes such as ascorbate peroxidase (APX, monodehydroascorbate reductase (MDHAR, dehydroascorbate reductase (DHAR and glutathione reductase (GR increased after Spd pretreatment in LT affected seedlings. Thus, the oxidative stress was reduced. Protective effects of Spd are also reflected from reduction of methylglyoxal (MG toxicity by improving glyoxalase cycle components, and by maintaining osmoregulation, water status and improved seedlings growth. The present study reveals the vital roles of AsA-GSH and glyoxalase cycle in alleviating LT injury.

Molecularly imprinted polyaniline-ferrocene-sulfonic acid-Carbon dots modified pencil graphite electrodes for chiral selective sensing of D-Ascorbic acid and L-Ascorbic acid: A clinical biomarker for preeclampsia

International Nuclear Information System (INIS)

Pandey, Indu; Jha, Shashank Shekhar

2015-01-01

Highlights: • Pencil graphite electrode was non-covalently functionalized by C-dots. • Electrochemically synthesized ferrocene-sulfonic acid doped PANI film was used as chiral recognition element. • Electrochemical chiral sensing of L-ascorbic acid and D-ascorbic acid was carried out. • L-ascorbic acid determination was done in aqueous, biological and pharmaceutical samples at nM level. - Abstract: A simple and novel method is proposed for chiral separation of L-ascorbic acid and D-ascorbic acid in human cerebrospinal fluids and blood plasma samples. Electro-polymerized molecularly imprinted poly-aniline ferrocenesulfonic acid-C-dots modified pencil graphite electrodes was successfully applied for separation and quantification of D-/L-ascorbic acid in aqueous and some biological samples. Parameters, important to control the performance of the electrochemical sensor were investigated and optimized, including the effects of pH, monomer- template ratios, electropolymerization cycles and scan rates. The molecularly imprinted film exhibited a high chiral selectivity and sensitivity towards D-ascorbic acid and L-ascorbic acid respectively. The surface morphologies and electrochemical properties of the proposed sensor were characterized by scanning electron microscopy, cyclic voltammetry, difference pulse voltammetry, chrono-amperometry and electrochemical impedance spectroscopy. L-ascorbic acid selective sensor shows excellent selectivity towards the L-ascorbic acid in comparison to D- ascorbic acid vice versa for D- ascorbic acid selective sensor. Under optimal conditions the linear range of the calibration curve for L- ascorbic acid and D- ascorbic acid was 6.0–165.0 nM and 6.0–155.0 nM, with the detection limit of 0.001 nM and 0.002 nM. Chiral detection of L-ascorbic acid was successfully carried out in pharmaceuticals and human plasma samples (pregnant women and non pregnant women) via proposed sensor with good selectivity and sensitivity.

Toxicity and removal efficiency of pharmaceutical metabolite clofibric acid by Typha spp.--potential use for phytoremediation?

Science.gov (United States)

Dordio, Ana V; Duarte, Cátia; Barreiros, Margarida; Carvalho, A J Palace; Pinto, A P; da Costa, Cristina Teixeira

2009-02-01

A study was conducted to assess Typha spp.'s ability to withstand and remove, from water, a metabolite of blood lipid regulator drugs, clofibric acid (CA). At a concentration of 20 microg L(-1), Typha had removed >50% of CA within the first 48h, reaching a maximum of 80% by the end of the assay. Experimental conditions assured that photodegradation, adsorption to vessel walls and microbial degradation did not contribute to the removal. Exposure to higher CA concentrations did not affect Typha's photosynthetic pigments but the overall increase in enzyme activity (ascorbate and guaiacol peroxidases, catalase, superoxide dismutase) indicates that both roots and leaves were affected by the xenobiotic. Eventually, Typha seemed able to cope with the CA's induced oxidative damage suggesting its ability for phytoremediation of CA contaminated waters.

Enzyme Technology of Peroxidases: Immobilization, Chemical and Genetic Modification

Science.gov (United States)

Longoria, Adriana; Tinoco, Raunel; Torres, Eduardo

An overview of enzyme technology applied to peroxidases is made. Immobilization on organic, inorganic, and hybrid supports; chemical modification of amino acids and heme group; and genetic modification by site-directed and random mutagenesis are included. Different strategies that were carried out to improve peroxidase performance in terms of stability, selectivity, and catalytic activity are analyzed. Immobilization of peroxidases on inorganic and organic materials enhances the tolerance of peroxidases toward the conditions normally found in many industrial processes, such as the presence of an organic solvent and high temperature. In addition, it is shown that immobilization helps to increase the Total Turnover Number at levels high enough to justify the use of a peroxidase-based biocatalyst in a synthesis process. Chemical modification of peroxidases produces modified enzymes with higher thermostability and wider substrate variability. Finally, through mutagenesis approaches, it is possible to produce modified peroxidases capable of oxidizing nonnatural substrates with high catalytic activity and affinity.

Production and Purification of Peroxidase from Aspergillus niger.

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Mohammed A. Jebor

2017-02-01

Full Text Available This study was conducted in the laboratories of Biology Department, College of Science, which deals with isolation and purification of peroxidase and optimization of process parameters to achieve maximum yield of peroxidase by Aspergillus niger. Solid-state fermentation of Aspergillus niger was carried out for enhanced production of peroxidase using hydrogen peroxide as the substrate of enzyme maximum activity of the enzyme was achieved under optimum growth conditions. The optimum conditions were the isolated of Aspergillus niger from soil and growth in synthetic medium, it gave high titer of peroxidase activity, the fructose as carbon source, peptone as nitrogen source, after 12 days of incubation, incubation temperature 25 °C and pH = 6.5. Peroxidase purified in four purification steps; precipitation with 70% saturation of ammonium sulfate, step of dialysis, the third by ion exchange chromatography using DEAE-Cellulose and fourth by gel filtration throughout Sephadex G-100. The specific activity of the purified enzyme was 150U/mg with 7.75 folds. The peroxidase was shown to have molecular weight of 40kDa in SDS-PAGA and about 40kDa in gel filtration.The optimum pH and temperature for peroxidase activity 7 and 35 C0 respectively.

Cadmium-induced oxidative damage and protective effects of N-acetyl-L-cysteine against cadmium toxicity in Solanum nigrum L

International Nuclear Information System (INIS)

Deng Xiaopeng; Xia Yan; Hu Wei; Zhang Hongxiao; Shen Zhenguo

2010-01-01

The effects of cadmium (Cd) on the accumulation of hydrogen peroxide (H 2 O 2 ) and antioxidant enzyme activities in roots of Solanum nigrum L. and the role of N-acetyl-L-cysteine (NAC) as a cysteine (Cys) donor against Cd toxicity were investigated. Cd at 50 and 200 μM significantly increased the contents of thiobarbituric acid-reactive substances (TBARS), the production of H 2 O 2 and superoxide anion (O 2 · - ), and the activities of catalase, guaiacol peroxidase, ascorbate peroxidase, glutathione peroxidase (GSH-Px), glutathione reductase, and superoxide dismutase. Experiments with diphenylene iodonium as an inhibitor of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase and NaN 3 as an inhibitor of peroxidase showed that the major source of Cd-induced reactive oxygen species in the roots may include plasma membrane-bound NADPH oxidase and peroxidase. In addition, the effects of NAC on plant growth, antioxidant enzyme activity, and non-protein thiol content were analyzed. Under Cd stress, the addition of 500 μM NAC decreased the contents of TBARS and production of H 2 O 2 and O 2 · - , but increased levels of Cys and reduced glutathione (GSH), phytochelatins, and activity of GSH-Px in roots. These results suggest that NAC could protect plants from oxidative stress damage, and this protection seems to be performed via increased GSH biosynthesis. Furthermore, NAC treatment also increased the contents of protein thiols in S. nigrum roots. By using size-exclusion chromatography, we found involvement of NAC in the Cd tolerance mechanism through increased biosynthesis of Cd-binding proteins.

Macrokinetics of magnesium sulfite oxidation inhibited by ascorbic acid

International Nuclear Information System (INIS)

Lidong, Wang; Yongliang, Ma; Wendi, Zhang; Qiangwei, Li; Yi, Zhao; Zhanchao, Zhang

2013-01-01

Graphical abstract: Ascorbic acid is used as an inhibitor to retard the oxidation rate of magnesium sulfite. It shows that the oxidation rate would decrease greatly with the rise of initial ascorbic acid concentration, which provides a useful reference for sulfite recovery in magnesia desulfurization. -- Highlights: • We studied the kinetics of magnesium sulfite oxidation inhibited by ascorbic acid. • The oxidation process was simulated by a three-phase model and proved by HPLC–MS. • We calculated the kinetic parameters of intrinsic oxidation of magnesium sulfite. -- Abstract: Magnesia flue gas desulfurization is a promising process for small to medium scale industrial coal-fired boilers in order to reduce sulfur dioxide emissions, in which oxidation control of magnesium sulfite is of great importance for the recycling of products. Effects of four inhibitors were compared by kinetic experiments indicating that ascorbic acid is the best additive, which retards the oxidation process of magnesium sulfite in trace presence. The macrokinetics of magnesium sulfite oxidation inhibited by ascorbic acid were studied. Effects of the factors, including ascorbic acid concentration, magnesium sulfite concentration, oxygen partial pressure, pH, and temperature, were investigated in a stirred reactor with bubbling. The results show that the reaction rate is −0.55 order in ascorbic acid, 0.77 in oxygen partial pressure, and zero in magnesium sulfite concentration, respectively. The apparent activation energy is 88.0 kJ mol −1 . Integrated with the kinetic model, it is concluded that the oxidation rate of magnesium sulfite inhibited by ascorbic acid is controlled by the intrinsic chemical reaction. The result provides a useful reference for sulfite recovery in magnesia desulfurization

Polarographic measurement of ascorbate washout in isolated perfused rabbit hearts

International Nuclear Information System (INIS)

Arts, T.; Kuikka, J.T.; Reneman, R.S.; Bassingthwaighte, J.B.

1985-01-01

To study the myocardial washout of ascorbate, the applicability of polarographic detection of ascorbate ions by a platinum electrode (sensitive area 0.03 mm2) was investigated, in both a calibration setup (sampling flow along the electrode: 100 microliter X s-1) and isolated, retrogradely perfused rabbit hearts. In the calibration setup at pH 7.4, the sensitivity of the electrode was 70 microA/mol. This sensitivity increased moderately with increasing pH (13%/unit pH) and increasing sampling flow rate (14% at an increase from 100 to 150 microliter X s-1). In the isolated hearts, ascorbate infused into the aorta was detected in a right ventricular drain by the electrode as well as by the use of 14 C-labeled ascorbate. Both recorded time courses were similar except for a scaling factor dependent on flow velocity. During continuous infusion the arteriovenous difference of ascorbate was 2 +/- 2% (SD), indicating a relatively low consumption of ascorbate by the isolated heart. The authors conclude that polarographic measurement of ascorbate in the coronary effluent of an isolated rabbit heart can be performed on-line and relatively easily

Measurement of binding of ascorbic acid to myrosinase by rate of dialysis

International Nuclear Information System (INIS)

Ohtsuru, Masaru; Hata, Tadao

1975-01-01

The activation mechanism of myrosinase by L-ascorbic acid depends on the slight conformational change of enzyme protein induced by ascorbic acid. Ascorbic acid binds to enzyme like Michaelis-complex, and then the value of Km had been evaluated to be 1 x 10 -3 M. The authors determined the binding constant and the number of binding sites using dialysis rate technique. Rate dialysis was carried out with a dialysis cell, and the ordinary cellophane tubing membrane was used. ( 14 C) - ascorbic acid was added, and counted by liquid scintillation counting. By the time course of two dialysis rate measurement with and without enzyme. The concentrations of free and bound ascorbic acids were counted. From the results, the enzyme was activated to the maximum level at 10 -3 M of ascorbic acid, and four molecules of ascorbic acid bound to the enzyme on Kd=0.1x10 -4 M. However, when more than 4 molecules of L-ascorbic acid bound to the enzyme, Kd increased to 0.9x10 -4 M, and L-ascorbic acid acted as an inhibitor. (Kubatake, H.)

Iodometric determination of the ascorbic acid (Vitamin c) content of ...

African Journals Online (AJOL)

The ascorbic acid content of seven different fruits –grapefruit, lime, orange, tangerine, banana, pawpaw and pineapple was determined by iodine titration, in order to know which fruit would best supply the ascorbic acid need for the body. Results showed that tangerine had the highest value of ascorbic acid, ...

Oral Metformin-Ascorbic Acid Co-Administration Ameliorates Alcohol ...

African Journals Online (AJOL)

Oral Metformin-Ascorbic Acid Co-Administration Ameliorates Alcohol-Induced Hepatotoxicity In Rats. ... Nigerian Quarterly Journal of Hospital Medicine ... the present in vivo animal study was to determine whether metformin-ascorbic acid co-administration also prevents alcoholic hepatotoxicity in chronic alcohol exposure.

Ascorbic acid: Nonradioactive extracellular space marker in canine heart

International Nuclear Information System (INIS)

Reil, G.H.; Frombach, R.; Kownatzki, R.; Quante, W.; Lichtlen, P.R.

1987-01-01

The distribution pattern of ascorbic acid and L-[ 14 C]ascorbic acid in myocardial tissue was compared with those of the classical radioactive extracellular space markers [ 3 H]-inulin, [ 3 H]sucrose, and Na 82 Br. A new polarographic techniques was developed for analogue registration of ascorbic acid concentration in coronary venous blood. The kinetic data of the markers were studied in an open-chest canine heart preparation during a constant tracer infusion of up to 9 min. Distribution volumes were calculated based on the mean transit time method of Zierler. The distribution volume of ascorbic acid as well as of L-[ 14 C]ascorbic acid in myocardial tissue agreed closely with those of [ 3 H]inulin and [ 3 H]sucrose as well as 82 Br. The obtained kinetic data confirmed that ascorbic acid exhibits the physicochemical properties of an extracellular space marker, though this compound was shown to leak slowly into myocardial cells. Favorable attributes of this indicator are its low molecular weight, high diffusibility in interstitial fluid, low binding affinity to macromolecules, and high transcapillary as well as low transplasmalemmal penetration rate. Therefore, this nonradioactive marker can be applied in a safe and simple fashion, and without untoward side effects in experimental animals as well as in patients

Degradation of L-Ascorbic Acid in the Amorphous Solid State.

Science.gov (United States)

Sanchez, Juan O; Ismail, Yahya; Christina, Belinda; Mauer, Lisa J

2018-03-01

Ascorbic acid degradation in amorphous solid dispersions was compared to its degradation in the crystalline state. Physical blends and lyophiles of ascorbic acid and polymers (pectins and polyvinylpyrrolidone [PVP]) were prepared initially at 50:50 (w/w), with further studies using the polymer that best inhibited ascorbic acid crystallization in the lyophiles in 14 vitamin : PVP ratios. Samples were stored in controlled environments (25 to 60 °C, 0% to 23% RH) for 1 mo and analyzed periodically to track the physical appearance, change in moisture content, physical state (powder x-ray diffraction and polarized light microscopy), and vitamin loss (high performance liquid chromatography) over time. The glass transition temperatures of select samples were determined using differential scanning calorimetry, and moisture sorption profiles were generated. Ascorbic acid in the amorphous form, even in the glassy amorphous state, was more labile than in the crystalline form in some formulations at the highest storage temperature. Lyophiles stored at 25 and 40 °C and those in which ascorbic acid had crystallized at 60 °C (≥70% ascorbic acid : PVP) had no significant difference in vitamin loss (P > 0.05) relative to physical blend controls, and the length of storage had little effect. At 60 °C, amorphous ascorbic acid lyophiles (≤60% ascorbic acid : PVP) lost significantly more vitamin (P vitamin loss significantly increased over time. In these lyophiles, vitamin degradation also significantly increased (P vitamins are naturally present or added at low concentrations and production practices may promote amorphization of the vitamin. Vitamin C is one of the most unstable vitamins in foods. This study documents that amorphous ascorbic acid is less stable than crystalline ascorbic acid in some environments (for example, higher temperatures within 1 wk), especially when the vitamin is present at low concentrations in a product. These findings increase the understanding of

Nitric Oxide in Plants: The Roles of Ascorbate and Hemoglobin

Science.gov (United States)

Wang, Xiaoguang; Hargrove, Mark S.

2013-01-01

Ascorbic acid and hemoglobins have been linked to nitric oxide metabolism in plants. It has been hypothesized that ascorbic acid directly reduces plant hemoglobin in support of NO scavenging, producing nitrate and monodehydroascorbate. In this scenario, monodehydroascorbate reductase uses NADH to reduce monodehydroascorbate back to ascorbate to sustain the cycle. To test this hypothesis, rates of rice nonsymbiotic hemoglobin reduction by ascorbate were measured directly, in the presence and absence of purified rice monodehydroascorbate reductase and NADH. Solution NO scavenging was also measured methodically in the presence and absence of rice nonsymbiotic hemoglobin and monodehydroascorbate reductase, under hypoxic and normoxic conditions, in an effort to gauge the likelihood of these proteins affecting NO metabolism in plant tissues. Our results indicate that ascorbic acid slowly reduces rice nonsymbiotic hemoglobin at a rate identical to myoglobin reduction. The product of the reaction is monodehydroascorbate, which can be efficiently reduced back to ascorbate in the presence of monodehydroascorbate reductase and NADH. However, our NO scavenging results suggest that the direct reduction of plant hemoglobin by ascorbic acid is unlikely to serve as a significant factor in NO metabolism, even in the presence of monodehydroascorbate reductase. Finally, the possibility that the direct reaction of nitrite/nitrous acid and ascorbic acid produces NO was measured at various pH values mimicking hypoxic plant cells. Our results suggest that this reaction is a likely source of NO as the plant cell pH drops below 7, and as nitrite concentrations rise to mM levels during hypoxia. PMID:24376554

Alleviation of isoproturon toxicity to wheat by exogenous application of glutathione.

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Nemat Alla, Mamdouh M; Hassan, Nemat M

2014-06-01

Treatment with the recommended field dose of isoproturon to 7-d-old wheat seedlings significantly decreased shoot height, fresh and dry weights during the subsequent 15days. Meanwhile contents of carotenoids, chlorophylls and anthocyanin as well as activities of δ-aminolevulinate dehydratase (ALA-D), phenylalanine ammonia lyase (PAL) and tyrosine ammonia lyase (TAL) were significantly inhibited. On the other hand, the herbicide significantly increased malondialdehyde (MDA), a naturally occurring product of lipid peroxidation and H2O2, while it significantly decreased the contents of glutathione (GSH) and ascorbic acid (AsA) and reduced the activities of superoxide dismutase (SOD), catalase (CAT) and ascorbate peroxidase (APX). These findings indicate an induction of a stress status in wheat seedlings following isoproturon treatment. However, exogenous GSH appeared to limit the toxic effects of isoproturon and seemed to overcome this stress status. Most likely, contents of pigment and activities of enzymes were raised to approximate control levels. Moreover, antioxidants were elevated and the oxidative stress indices seemed to be alleviated by GSH application. These results indicate that exogenous GSH enhances enzymatic and nonenzymatic antioxidants to alleviate the effects of isoproturon. Copyright © 2014 Elsevier Inc. All rights reserved.

Data supporting the role of enzymes and polysaccharides during cassava postharvest physiological deterioration.

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Uarrota, Virgílio Gavicho; Moresco, Rodolfo; Schmidt, Eder Carlos; Bouzon, Zenilda Laurita; da Costa Nunes, Eduardo; de Oliveira Neubert, Enilto; Peruch, Luiz Augusto Martins; Rocha, Miguel; Maraschin, Marcelo

2016-03-01

This data article is referred to the research article entitled The role of ascorbate peroxidase, guaiacol peroxidase, and polysaccharides in cassava (Manihot esculenta Crantz) roots under postharvest physiological deterioration by Uarrota et al. (2015). Food Chemistry 197, Part A, 737-746. The stress duo to PPD of cassava roots leads to the formation of ROS which are extremely harmful and accelerates cassava spoiling. To prevent or alleviate injuries from ROS, plants have evolved antioxidant systems that include non-enzymatic and enzymatic defence systems such as ascorbate peroxidase, guaiacol peroxidase and polysaccharides. In this data article can be found a dataset called "newdata", in RData format, with 60 observations and 06 variables. The first 02 variables (Samples and Cultivars) and the last 04, spectrophotometric data of ascorbate peroxidase, guaiacol peroxidase, tocopherol, total proteins and arcsined data of cassava PPD scoring. For further interpretation and analysis in R software, a report is also provided. Means of all variables and standard deviations are also provided in the Supplementary tables ("data.long3.RData, data.long4.RData and meansEnzymes.RData"), raw data of PPD scoring without transformation (PPDmeans.RData) and days of storage (days.RData) are also provided for data analysis reproducibility in R software.

ANTIOXIDANT AND PRO-OXIDANT EFFECT OF ASCORBIC ACID

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Goran Rankovic

2005-01-01

Full Text Available Free radicals attack proteins, lipids, enzymes and DNA causing pathological changes in organism. There are many mechanisms that organism uses to fight against free radicals. Ascorbic acid is one of the strongest reducers and eliminators of free radicals. It reduces stable oxygenic, azoth and thyol radicals and acts as a primary defense against water radicals in blood. When radicals are dissolved in water suspensions of erythrocytes and low density lipoproteins (LDL, ascorbic acid catches and eliminates free radicals before they arrive to the membrane and LDL molecules. Even though ascorbic acid is not capable of eliminating free radicals out of fluid medium, it acts as synergist to alpha-tocopherol in lipid section, contributes to the lessening of lipid tocoperoxil radicals, and above all, regenerates alpha-tocopherol. Ascorbic acid may act as pro-oxidant under in vitro conditions in the presence of metals; however, this effect is probably not important under in vivo conditions where metal ions, being sequestered, become second reducers.

Enhanced salt-induced antioxidative responses involve a contribution of polyamine biosynthesis in grapevine plants.

Science.gov (United States)

Ikbal, Fatima Ezzohra; Hernández, José Antonio; Barba-Espín, Gregorio; Koussa, Tayeb; Aziz, Aziz; Faize, Mohamed; Diaz-Vivancos, Pedro

2014-06-15

The possible involvement of polyamines in the salt stress adaptation was investigated in grapevine (Vitis vinifera L.) plantlets focusing on photosynthesis and oxidative metabolism. Salt stress resulted in the deterioration of plant growth and photosynthesis, and treatment of plantlets with methylglyoxal-bis(guanylhydrazone) (MGBG), a S-adenosylmethionine decarboxylase (SAMDC) inhibitor, enhanced the salt stress effect. A decrease in PSII quantum yield (Fv/Fm), effective PSII quantum yield (Y(II)) and coefficient of photochemical quenching (qP) as well as increases in non-photochemical quenching (NPQ) and its coefficient (qN) was observed by these treatments. Salt and/or MGBG treatments also triggered an increase in lipid peroxidation and reactive oxygen species (ROS) accumulation as well as an increase of superoxide dismutase (SOD) and peroxidase (POX) activities, but not ascorbate peroxidase (APX) activity. Salt stress also resulted in an accumulation of oxidized ascorbate (DHA) and a decrease in reduced glutathione. MGBG alone or in combination with salt stress increased monodehydroascorbate reductase (MDHAR), SOD and POX activities and surprisingly no accumulation of DHA was noticed following treatment with MGBG. These salt-induced responses correlated with the maintaining of high level of free and conjugated spermidine and spermine, whereas a reduction of agmatine and putrescine levels was observed, which seemed to be amplified by the MGBG treatment. These results suggest that maintaining polyamine biosynthesis through the enhanced SAMDC activity in grapevine leaf tissues under salt stress conditions could contribute to the enhanced ROS scavenging activity and a protection of photosynthetic apparatus from oxidative damages. Copyright © 2014 Elsevier GmbH. All rights reserved.

Antagonism of ascorbate against the radioprotective action of cysteamine

Energy Technology Data Exchange (ETDEWEB)

Naeslund, M; Ehrenberg, L; Djalali-Behzad, G [Stockholm Univ. (Sweden). Radiobiologiska Institutionen

1976-07-01

An investigation has been carried out into the interaction of cysteamine (MEA) and ascorbate on the radiosensitivity of E.coli, with painstaking removal of autoxidation products from glassware. Trace amounts of copper could be effectively removed, and the influence of small amounts of iron contaminating the analytical grade phosphate was assessed. The bacteria were exposed to MEA and/or ascorbate for 1 hour at 37/sup 0/C, irradiation with 42 or 58 krad of /sup 60/Co ..gamma..rays taking place 30 to 40 minutes after the additions. Survival studies demonstrated the reversion of a major fraction of the radioprotective action of MEA (2 or 6 mM) by ascorbate (5 mM) simultaneously present in the medium. Net RNA synthesis, determined by the incorporation of /sup 3/H-uridine, was suppressed by MEA and this was partly reversed by ascorbate. The irradiation of bacterium suspensions containing MEA and ascorbate was found to provoke a conspicuous stimulation of RNA synthesis above the level of unirradiated parallel samples. The effects of some oxidizing treatments (dehydroascorbic acid, hydrogen peroxide, 3.6 ..mu..M FeSO/sub 4/ or 1 ..mu..M CuSO/sub 4/) together with MEA were also studied. Possible mechanisms for the ability of ascorbate to counteract the radioprotective action of MEA are discussed, and the implication of monodehydroascorbate formed during irradiation is suggested.

Comparative study of peroxidase purification from apple and orange ...

African Journals Online (AJOL)

This paper reports the isolation and purification of peroxidase from low cost material; moreover, no significant work has been done on the isolation and purification of peroxidase from such cost effective sources (apple and orange seeds). Peroxidases had attracted considerable interest in recent years because of their ...

Models of Superoxide Dismutases

Energy Technology Data Exchange (ETDEWEB)

Cabelli, Diane E.; Riley, Dennis; Rodriguez, Jorge A.; Valentine, Joan Selverstone; Zhu, Haining

1998-05-20

In this review we have focused much of our discussion on the mechanistic details of how the native enzymes function and how mechanistic developments/insights with synthetic small molecule complexes possessing SOD activity have influenced our understanding of the electron transfer processes involved with the natural enzymes. A few overriding themes have emerged. Clearly, the SOD enzymes operate at near diffusion controlled rates and to achieve such catalytic turnover activity, several important physical principles must be operative. Such fast electron transfer processes requires a role for protons; i.e., proton-coupled electron transfer (''H-atom transfer'') solves the dilemma of charge separation developing in the transition state for the electron transfer step. Additionally, outer-sphere electron transfer is likely a most important pathway for manganese and iron dismutases. This situation arises because the ligand exchange rates on these two ions in water never exceed {approx}10{sup +7} s{sup -1}; consequently, 10{sup +9} catalytic rates require more subtle mechanistic insights. In contrast, copper complexes can achieve diffusion controlled (>10{sup +9}) exchange rates in water; thus inner-sphere electron transfer processes are more likely to be operative in the Cu/Zn enzymes. Recent studies have continued to expand our understanding of the mechanism of action of this most important class of redox active enzymes, the superoxide dismutases, which have been critical in the successful adaptation of life on this planet to an oxygen-based metabolism. The design of SOD mimic drugs, synthetic models compounds that incorporate this superoxide dismutase catalytic activity and are capable of functioning in vivo, offers clear potential benefits in the control of diseases, ranging from the control of neurodegenerative conditions, such as Parkinson's or Alzheimer's disease, to cancer.

Induction of Laccase, Lignin Peroxidase and Manganese Peroxidase Activities in White-Rot Fungi Using Copper Complexes

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Martina Vrsanska

2016-11-01

Full Text Available Ligninolytic enzymes, such as laccase, lignin peroxidase and manganese peroxidase, are biotechnologically-important enzymes. The ability of five white-rot fungal strains Daedaleopsis confragosa, Fomes fomentarius, Trametes gibbosa, Trametes suaveolens and Trametes versicolor to produce these enzymes has been studied. Three different copper(II complexes have been prepared ((Him[Cu(im4(H2O2](btc·3H2O, where im = imidazole, H3btc = 1,3,5-benzenetricarboxylic acid, [Cu3(pmdien3(btc](ClO43·6H2O and [Cu3(mdpta3(btc](ClO43·4H2O, where pmdien = N,N,N′,N′′,N′′-pentamethyl-diethylenetriamine and mdpta = N,N-bis-(3-aminopropylmethyl- amine, and their potential application for laccase and peroxidases induction have been tested. The enzyme-inducing activities of the complexes were compared with that of copper sulfate, and it has been found that all of the complexes are suitable for the induction of laccase and peroxidase activities in white-rot fungi; however, the newly-synthesized complex M1 showed the greatest potential for the induction. With respect to the different copper inducers, this parameter seems to be important for enzyme activity, which depends also on the fungal strains.

Peroxidase activity in root hairs of cress (lepidium sativum L.) Cytochemical localization and radioactive labelling of wall bound peroxidase

International Nuclear Information System (INIS)

Zaar, K.

1979-01-01

The ultrastructural localization of peroxidase activity in young, growing root hairs of cress (Lepidium sativum L.) after assay with 3,3'-diaminobenzidine is reported. Prominent peroxidase activity has been found in the dictyosomes and the associated vesicles, in ribosomes on ER-cisternae, as well as in the cell wall. On the basis of both ultrastructural and cytochemical evidence it is proposed that peroxidase in root hairs is synthesized on the ER- and within dictyosome cisternae packaged and transported in secretory vesicles and extruded into the cell wall particularily at the tip region of a root hair. The kinetic of Golgi apparatus mediated peroxidasesecretion was monitored by measuring the 55 Fe protoheme content of primary cell walls. Peroxidase secretion seems to be enhanced during stress incubation in destilled water. Secretory activity in root hairs is 20 times higher than in cells of the root body. (author)

Drug Nanoparticle Formulation Using Ascorbic Acid Derivatives

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Kunikazu Moribe

2011-01-01

Full Text Available Drug nanoparticle formulation using ascorbic acid derivatives and its therapeutic uses have recently been introduced. Hydrophilic ascorbic acid derivatives such as ascorbyl glycoside have been used not only as antioxidants but also as food and pharmaceutical excipients. In addition to drug solubilization, drug nanoparticle formation was observed using ascorbyl glycoside. Hydrophobic ascorbic acid derivatives such as ascorbyl mono- and di-n-alkyl fatty acid derivatives are used either as drugs or carrier components. Ascorbyl n-alkyl fatty acid derivatives have been formulated as antioxidants or anticancer drugs for nanoparticle formulations such as micelles, microemulsions, and liposomes. ASC-P vesicles called aspasomes are submicron-sized particles that can encapsulate hydrophilic drugs. Several transdermal and injectable formulations of ascorbyl n-alkyl fatty acid derivatives were used, including ascorbyl palmitate.

Piper betle shows antioxidant activities, inhibits MCF-7 cell proliferation and increases activities of catalase and superoxide dismutase

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Abrahim Noor

2012-11-01

Full Text Available Abstract Background Breast cancer is the most common form of cancer and the focus on finding chemotherapeutic agents have recently shifted to natural products. Piper betle is a medicinal plant with various biological activities. However, not much data is available on the anti-cancer effects of P. betle on breast cancer. Due to the current interest in the potential effects of antioxidants from natural products in breast cancer treatment, we investigated the antioxidant activities of the leaves of P. betle and its inhibitory effect on the proliferation of the breast cancer cell line, MCF-7. Methods The leaves of P. betle were extracted with solvents of varying polarities (water, methanol, ethyl acetate and hexane and their phenolic and flavonoid content were determined using colorimetric assays. Phenolic composition was characterized using HPLC. Antioxidant activities were measured using FRAP, DPPH, superoxide anion, nitric oxide and hyroxyl radical scavenging assays. Biological activities of the extracts were analysed using MTT assay and antioxidant enzyme (catalase, superoxide dismutase, glutathione peroxidase assays in MCF-7 cells. Results Overall, the ethyl acetate extract showed the highest ferric reducing activity and radical scavenging activities against DPPH, superoxide anion and nitric oxide radicals. This extract also contained the highest phenolic content implying the potential contribution of phenolics towards the antioxidant activities. HPLC analyses revealed the presence of catechin, morin and quercetin in the leaves. The ethyl acetate extract also showed the highest inhibitory effect against the proliferation of MCF-7 cells (IC50=65 μg/ml. Treatment of MCF-7 cells with the plant extract increased activities of catalase and superoxide dismutase. Conclusions Ethyl acetate is the optimal solvent for the extraction of compounds with antioxidant and anti-proliferative activities. The increased activities of catalase and superoxide

Piper betle shows antioxidant activities, inhibits MCF-7 cell proliferation and increases activities of catalase and superoxide dismutase.

Science.gov (United States)

Abrahim, Noor Nazirahanie; Kanthimathi, M S; Abdul-Aziz, Azlina

2012-11-15

Breast cancer is the most common form of cancer and the focus on finding chemotherapeutic agents have recently shifted to natural products. Piper betle is a medicinal plant with various biological activities. However, not much data is available on the anti-cancer effects of P. betle on breast cancer. Due to the current interest in the potential effects of antioxidants from natural products in breast cancer treatment, we investigated the antioxidant activities of the leaves of P. betle and its inhibitory effect on the proliferation of the breast cancer cell line, MCF-7. The leaves of P. betle were extracted with solvents of varying polarities (water, methanol, ethyl acetate and hexane) and their phenolic and flavonoid content were determined using colorimetric assays. Phenolic composition was characterized using HPLC. Antioxidant activities were measured using FRAP, DPPH, superoxide anion, nitric oxide and hyroxyl radical scavenging assays. Biological activities of the extracts were analysed using MTT assay and antioxidant enzyme (catalase, superoxide dismutase, glutathione peroxidase) assays in MCF-7 cells. Overall, the ethyl acetate extract showed the highest ferric reducing activity and radical scavenging activities against DPPH, superoxide anion and nitric oxide radicals. This extract also contained the highest phenolic content implying the potential contribution of phenolics towards the antioxidant activities. HPLC analyses revealed the presence of catechin, morin and quercetin in the leaves. The ethyl acetate extract also showed the highest inhibitory effect against the proliferation of MCF-7 cells (IC50=65 μg/ml). Treatment of MCF-7 cells with the plant extract increased activities of catalase and superoxide dismutase. Ethyl acetate is the optimal solvent for the extraction of compounds with antioxidant and anti-proliferative activities. The increased activities of catalase and superoxide dismutase in the treated cells could alter the antioxidant defense

Antioxidant and carbohydrate changes of two pomegranate cultivars under deficit irrigation stress

International Nuclear Information System (INIS)

Ebtedaie, M.; Shekafandeh, A.

2016-01-01

The purpose of this study was to evaluate the biochemical responses to water stress tolerance of two pomegranate cultivars, ‘Rabbab’ and ‘Shishehgap’. After the establishment of rooted stem cuttings of both cultivars under greenhouse conditions, they were treated with four levels of deficit irrigations (100%, 75%, 50% and 25% of field capacity) in a completely randomized design with four replications. The results showed a significant difference between the two cultivars regarding antioxidant enzymes activities. In both cultivars, the water stress increased the activity of superoxide dismutase, catalase and ascorbate peroxidase. However, at high water deficit (25% field capacity, FC), ‘Rabbab’ showed significantly higher enzyme activity than ‘Shishehgap’. In each level of irrigation, there were not considerable differences in peroxidase activity between the two cultivars. An increment of 162% and 65.5% in soluble sugar was gained at 50% FC in ‘Rabbab’ and ‘Shishehgap’, respectively. ‘Rabbab’ showed better growth performance in each level of irrigation than ‘Shishehgap’. Therefore, it can be concluded that 'Rabbab', with lesser decline in leaf relative water content (RWC), a strong antioxidant system and accumulation of more soluble carbohydrates, can resist higher water stress than 'Shishehgap'.

Effects of CO2 Enrichment on Growth and Development of Impatiens hawkeri

Science.gov (United States)

Zhang, Fan-Fan; Wang, Yan-Li; Huang, Zhi-Zhe; Zhu, Xiao-Chen; Zhang, Feng-Jiao; Chen, Fa-Di; Fang, Wei-Min; Teng, Nian-Jun

2012-01-01

The effects of CO2 enrichment on growth and development of Impatiens hawkeri, an important greenhouse flower, were investigated for the purpose of providing scientific basis for CO2 enrichment to this species in greenhouse. The plants were grown in CO2-controlled growth chambers with 380 (the control) and 760 (CO2 enrichment) μmol·mol−1, respectively. The changes in morphology, physiology, biochemistry, and leaf ultrastructure of Impatiens were examined. Results showed that CO2 enrichment increased flower number and relative leaf area compared with the control. In addition, CO2 enrichment significantly enhanced photosynthetic rate, contents of soluble sugars and starch, activities of peroxidase (POD), superoxide dismutase (SOD), and ascorbate peroxidase (APX), but reduced chlorophyll content and malondialdehyde (MDA) content. Furthermore, significant changes in chloroplast ultrastructure were observed at CO2 enrichment: an increased number of starch grains with an expanded size, and an increased ratio of stroma thylakoid to grana thylakoid. These results suggest that CO2 enrichment had positive effects on Impatiens, that is, it can improve the visual value, promote growth and development, and enhance antioxidant capacity. PMID:22536147

Growth and physiological response of lemongrass (Cymbopogon citratus (D.C.) Stapf.) under different levels of fly ash-amended soil.

Science.gov (United States)

Panda, Debabrata; Panda, Dibyajyoti; Padhan, Bandana; Biswas, Meghali

2018-05-12

Revegetation with metal tolerant plants for management of fly ash deposits is an important environmental perspective nowadays. Growth performance, photosynthesis, and antioxidant defense of lemongrass (Cymbopogon citratus (D.C.) Stapf.) were evaluated under various combination of fly ash amended with garden soil in order to assess its fly ash tolerance potential. Under low level of fly ash (25%) amended soil, the plant growth parameters such as shoot, root, and total plant biomass as well as metal tolerance index were increased compared to the control plants grown on garden soil, followed by decline under higher concentration of fly ash (50%, 75% and 100%). In addition, leaf photosynthetic rate, stomatal conductance, and photosystem (PS) II activity were not significantly changed under low level of fly ash (25%) amended soil compared to the garden soil but these parameters were significantly decreased further with increase of fly ash concentrations. Furthermore, increase of activities of some antioxidant enzymes such as superoxide dismutase, ascorbate peroxidase, and guaiacol peroxidase over control were noticed in lemongrass under all fly ash treatments. Taken together, the study suggests that lemongrass can be used for phytoremediation of fly ash at 25% amended soil.

Antioxidant activity of Trifolium resupinatum L. exposed to different extracts from leaves, flowers and shoots of Prangos ferulacea

Energy Technology Data Exchange (ETDEWEB)

Bazdar, M.; Sadeghi, H.

2017-07-01

Prangos ferulacea is a member of Apiaceae family, is a popular fodder for livestock production and an important species in rangeland restoration. The objectives of the research are the comparative phytotoxic activity of aqueous and hydroalcoholic extracts obtained from different organs (flower, shoot and leaf) of P. ferulacea on antioxidant response of Trifolium resupinatum was investigated in a laboratory bioassay. Antioxidant enzyme activities including catalase (CAT), peroxidase (POD), ascorbic peroxidase (APX), and superoxide dismutase (SOD), in line with content of malondialdehyde (MDA) and hydrogen peroxide were measured. Results indicated that hydroalcoholic extract of P. ferulaceae flower possess the highest total phenolic content as well as highest phytotoxic effect on T. resupinatum. The highest antioxidant enzyme activity belonged to hydroalcoholic treatment. The treated T. resupinatum seedlings experienced lipid peroxidation at high extract concentrations (12% of hydroalcoholic and 100% of aqueous extract) as evidenced by increased concentration of MDA. In response to this, the activities of SOD, CAT, POD and APX increased at lower extract concentrations but significantly dropped as concentrations increased. According to results of this study, rehabilitation of T. resupinatum sites through the use of P. ferulaceae will probably not be successful.

Effect of salinity on biomass production and activities of some key enzymatic antioxidants in kochia (kochia scoparia)

International Nuclear Information System (INIS)

Nabati, J.; Masoumi, A.; Mehrjerd, M.Z.; Kafi, M.; Nezami, A.; Moghaddam, P.R.

2011-01-01

Soil salinity is a major constraint to food production due to its negative impact on crop yield. Kochia (Kochia scoparia) is a salinity-resistant plant that can widely be used as emergency forage for livestock by using saline waters and soils in desert ecosystems. In order to investigate physiological mechanism, antioxidants activity and potential production of Kochia in response to different levels of salinity, an experiment was performed in a split plot based on randomized complete block design with three replications. Saline waters (5.2, 10.5 and 23.1 dS m/sup -1/) and three Kochia ecotypes (Birjand, Borujerd and Sabzevar) were allocated as main and sub plots, respectively. The results showed that salinity did not impose any significant effect on dry matter production but relative water content (RWC) and seed yield decreased by salinity stress. In general, no positive correlation coefficient was observed between dry matter production and physiological and biochemical parameters except superoxide dismutase (SOD) at 23.1 dS m/sup -1/. There was no significant difference among ecotypes in dry matter production and seed yield. Sabzevar ecotype showed the highest proline, total phenol content and peroxidase (POX) activity. Ascorbate peroxidase (APX), catalase (CTA), and superoxide dismutase (SOD) activity was higher in Borujerd ecotype, while highest soluble sugar, glutathione reductase (GR) activity and DPPH - radical scavenging activity was observed in Birjand ecotype. According to these results, Kochia has a reliable tolerance to elevated levels of salinities up to 23 dS m/sup -1/ and it seems that it can control oxidative stress by continuing growth. (author)

Seed priming with hormones does not alleviate induced oxidative stress in maize seedlings subjected to salt stress

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Rogério Falleiros Carvalho

2011-10-01

Full Text Available Seed priming with hormones has been an efficient method for increasing seed vigor as well as seedling growth under stressful conditions. These responses have in the past been attributed to the activation of antioxidant systems in a range of crops. The results described in this work show that hormonal priming with methyl jasmonate, salicylic acid or CEPA (chloroethylphosphonic acid, an ethylene (ET releaser, does not induce the antioxidant activity of superoxide dismutase, catalase, ascorbate peroxidase or glutathione reductase in maize seedlings subjected to salt stress. The enhanced biomass of maize seedlings under salt stress that was observed only from ET priming indicates that the stress tolerance in maize from ethylene priming is a fundamental process for stress tolerance acquisition, which is explained, however, by other biochemical mechanisms but not by changes in the antioxidant system.

The relationship between lignin peroxidase and manganese peroxidase production capacities and cultivation periods of mushrooms.

Science.gov (United States)

Xu, Jian Z; Zhang, Jun L; Hu, Kai H; Zhang, Wei G

2013-05-01

Mushrooms are able to secrete lignin peroxidase (LiP) and manganese peroxidase (MnP), and able to use the cellulose as sources of carbon. This article focuses on the relation between peroxidase-secreting capacity and cultivation period of mushrooms with non-laccase activity. Methylene blue and methyl catechol qualitative assay and spectrophotometry quantitative assay show LiP secreting unvaryingly accompanies the MnP secreting in mushroom strains. The growth rates of hyphae are detected by detecting the dry hyphal mass. We link the peroxidase activities to growth rate of mushrooms and then probe into the relationship between them. The results show that there are close relationships between LiP- and/or MnP-secretory capacities and the cultivation periods of mushrooms. The strains with high LiP and MnP activities have short cultivation periods. However, those strains have long cultivation periods because of the low levels of secreted LiP and/or MnP, even no detectable LiP and/or MnP activity. This study provides the first evidence on the imitate relation between the level of secreted LiP and MnP activities and cultivation periods of mushrooms with non-laccase activity. Our study has significantly increased the understanding of the role of LiP and MnP in the growth and development of mushrooms with non-laccase activity. © 2012 The Authors. Microbial Biotechnology © 2012 Society for Applied Microbiology and Blackwell Publishing Ltd.

Effects of cytochalasin B on the uptake of ascorbic acid and glucose by 3T3 fibroblasts: Mechanism of impaired ascorbate transport in diabetes

International Nuclear Information System (INIS)

Fay, M.J.; Bush, M.J.; Verlangieri, A.J.

1990-01-01

Hyperglycemia and/or hypoinsulinemia have been found to inhibit L-ascorbic acid cellular transport. The resultant decrease in intracellular ascorbic acid may de-inhibit aryl sulfatase B and increase degradation of sulfated glycosaminoglycans (sGAG). This could lead to a degeneration of the extracellular matrix and result in increased intimal permeability, the initiating event in atherosclerosis. The present studies show that the glucose transport inhibitor cytochalasin B blocked the uptake of 3 H-2-deoxy-D-glucose by mouse 3T3 fibroblasts. Cytochalasin B also blocked the uptake of 14 C-L-ascorbic acid. The results of these studies further support the hypothesis that glucose and ascorbate share a common transport system. This may have important implications concerning the vascular pathology associated with diabetes mellitus

The kinetics of oxidation of bilirubin and ascorbic acid in solution

Science.gov (United States)

Solomonov, A. V.; Rumyantsev, E. V.; Kochergin, B. A.; Antina, E. V.

2012-07-01

The results of a comparative study of the oxidation of bilirubin, ascorbic acid, and their mixture in aqueous solutions under the action of air oxygen and hydrogen peroxide are presented. The observed and true rate constants for the oxidation reactions were determined. It was shown that the oxidation of tetrapyrrole pigment occurred under these conditions bypassing the stage of biliverdin formation to monopyrrole products. Simultaneous oxidation of bilirubin and ascorbic acid was shown to be accompanied by the inhibition of ascorbic acid oxidation by bilirubin, whereas ascorbic acid itself activated the oxidation of bilirubin.

Cell wall bound anionic peroxidases from asparagus byproducts.

Science.gov (United States)

Jaramillo-Carmona, Sara; López, Sergio; Vazquez-Castilla, Sara; Jimenez-Araujo, Ana; Rodriguez-Arcos, Rocio; Guillen-Bejarano, Rafael

2014-10-08

Asparagus byproducts are a good source of cationic soluble peroxidases (CAP) useful for the bioremediation of phenol-contaminated wastewaters. In this study, cell wall bound peroxidases (POD) from the same byproducts have been purified and characterized. The covalent forms of POD represent >90% of the total cell wall bound POD. Isoelectric focusing showed that whereas the covalent fraction is constituted primarily by anionic isoenzymes, the ionic fraction is a mixture of anionic, neutral, and cationic isoenzymes. Covalently bound peroxidases were purified by means of ion exchange chromatography and affinity chromatography. In vitro detoxification studies showed that although CAP are more effective for the removal of 4-CP and 2,4-DCP, anionic asparagus peroxidase (AAP) is a better option for the removal of hydroxytyrosol (HT), the main phenol present in olive mill wastewaters.

Glycosylation and thermodynamic versus kinetic stability of horseradish peroxidase

DEFF Research Database (Denmark)

Tams, J.W.; Welinder, Karen G.

1998-01-01

Glycoprotein stability, glycoprotein unfolding, horseradish peroxidase, thermodynamic stability, kinetik stability......Glycoprotein stability, glycoprotein unfolding, horseradish peroxidase, thermodynamic stability, kinetik stability...

Role Of Ascorbic Acid In Imparting Tolerance To Plants Against Oxidizing Pollutants

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Priyanka Sharma

2015-08-01

Full Text Available Ascorbic acid is an antioxidant in plants which play important role in activation of many physiological and defense mechanisms. The level of ascorbic acid in plants is determinant of its tolerance against the adverse effect of oxidizing pollutants. The present study tries to relate the variation in ascorbic acid content with the tolerance and sensitivity of two selected plant species viz. Azadirachtaindica and Pongamiapinnata by calculating their Air Pollution Tolerance Index APTI during winter season from November to March in the urban city Delhi of North India. Moreover ascorbic acid is also an important part of chloroplast it protects different components of photosynthetic system from oxidative stress. Thus to understand the role of ascorbic acid in imparting tolerance to plants against oxidizing pollutants the changes in chlorophyll content of the selected plant species with variation in ambient ozone concentration was analysed. It was found that as per APTI values Azadirachta sp. came under tolerant range with highest ascorbic acid content whereas Pongamia sp. was under intermediate range with less ascorbic acid content. It was statistically established that ozone has no significant relation with chlorophyll content of Azadirachta sp. which has the highest ascorbic acid content. Whereas ambient ozone concentrations showed significant negative relation with the chlorophyll content of Pongamia sp. p 0.05. Thus it was observed that the plants with high ascorbic acid content are tolerant and have greater ability to remediate pollutants.

Cadmium-induced oxidative damage and protective effects of N-acetyl-L-cysteine against cadmium toxicity in Solanum nigrum L

Energy Technology Data Exchange (ETDEWEB)

Deng Xiaopeng; Xia Yan; Hu Wei [College of Life Sciences, Nanjing Agricultural University, Weigang 1, Nanjing 210095 (China); Zhang Hongxiao, E-mail: hxzhang@njau.edu.cn [College of Life Sciences, Nanjing Agricultural University, Weigang 1, Nanjing 210095 (China); Shen Zhenguo, E-mail: zgshen@njau.edu.cn [College of Life Sciences, Nanjing Agricultural University, Weigang 1, Nanjing 210095 (China)

2010-08-15

The effects of cadmium (Cd) on the accumulation of hydrogen peroxide (H{sub 2}O{sub 2}) and antioxidant enzyme activities in roots of Solanum nigrum L. and the role of N-acetyl-L-cysteine (NAC) as a cysteine (Cys) donor against Cd toxicity were investigated. Cd at 50 and 200 {mu}M significantly increased the contents of thiobarbituric acid-reactive substances (TBARS), the production of H{sub 2}O{sub 2} and superoxide anion (O{sub 2}{center_dot}{sup -}), and the activities of catalase, guaiacol peroxidase, ascorbate peroxidase, glutathione peroxidase (GSH-Px), glutathione reductase, and superoxide dismutase. Experiments with diphenylene iodonium as an inhibitor of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase and NaN{sub 3} as an inhibitor of peroxidase showed that the major source of Cd-induced reactive oxygen species in the roots may include plasma membrane-bound NADPH oxidase and peroxidase. In addition, the effects of NAC on plant growth, antioxidant enzyme activity, and non-protein thiol content were analyzed. Under Cd stress, the addition of 500 {mu}M NAC decreased the contents of TBARS and production of H{sub 2}O{sub 2} and O{sub 2}{center_dot}{sup -}, but increased levels of Cys and reduced glutathione (GSH), phytochelatins, and activity of GSH-Px in roots. These results suggest that NAC could protect plants from oxidative stress damage, and this protection seems to be performed via increased GSH biosynthesis. Furthermore, NAC treatment also increased the contents of protein thiols in S. nigrum roots. By using size-exclusion chromatography, we found involvement of NAC in the Cd tolerance mechanism through increased biosynthesis of Cd-binding proteins.

Formation of a tyrosine adduct involved in lignin degradation by Trametopsis cervina lignin peroxidase: a novel peroxidase activation mechanism

Science.gov (United States)

Yuta Miki; Rebecca Pogni; Sandra Acebes; Fatima Lucas; Elena Fernandez-Fueyo; Maria Camilla Baratto; Maria I. Fernandez; Vivian De Los Rios; Francisco J. Ruiz-duenas; Adalgisa Sinicropi; Riccardo Basosi; Kenneth E. Hammel; Victor Guallar; Angel T. Martinez

2013-01-01

LiP (lignin peroxidase) from Trametopsis cervina has an exposed catalytic tyrosine residue (Tyr181) instead of the tryptophan conserved in other lignin-degrading peroxidases. Pristine LiP showed a lag period in VA (veratryl alcohol) oxidation. However, VA-LiP (LiP after treatment with H2O2...

Radiation protection by ascorbic acid in sodium alginate solutions

Energy Technology Data Exchange (ETDEWEB)

Aliste, A.J.; Mastro, N.L. Del [Center of Radiation Technology, IPEN/CNEN/SP, University City, 05508-000 Sao Paulo (Brazil)]. E-mail: ajaliste@ipen.br

2004-07-01

Alginates are gelling hydrocolloids extracted from brown seaweed used widely in the nourishing and pharmaceutical industries. As alginic acid gellification retard food entrance in the stomach alginate is an additive used in diets. The objective of this work was to study the protective action of the ascorbic acid in alginate solutions against the action of {sup 60} Co gamma radiation. One % (w/v) solutions of alginate had been used and concentrations of ascorbic acid varied from 0 to 2.5% (w/v). The solutions were irradiated with doses up to 10 kGy. Viscosity/dose relationship and the p H of the solutions at 25 Centigrade were determined. Ascorbic acid behaved as an antioxidant against radiation oxidative shock in this model system of an irradiated viscous solution. Besides its radiation protective role on alginate solutions ascorbic acid promoted a viscosity increase in the range of concentrations employed. (Author)

Radiation protection by ascorbic acid in sodium alginate solutions

International Nuclear Information System (INIS)

Aliste, A.J.; Mastro, N.L. Del

2004-01-01

Alginates are gelling hydrocolloids extracted from brown seaweed used widely in the nourishing and pharmaceutical industries. As alginic acid gellification retard food entrance in the stomach alginate is an additive used in diets. The objective of this work was to study the protective action of the ascorbic acid in alginate solutions against the action of 60 Co gamma radiation. One % (w/v) solutions of alginate had been used and concentrations of ascorbic acid varied from 0 to 2.5% (w/v). The solutions were irradiated with doses up to 10 kGy. Viscosity/dose relationship and the p H of the solutions at 25 Centigrade were determined. Ascorbic acid behaved as an antioxidant against radiation oxidative shock in this model system of an irradiated viscous solution. Besides its radiation protective role on alginate solutions ascorbic acid promoted a viscosity increase in the range of concentrations employed. (Author)

Green reduction of graphene oxide by ascorbic acid

Science.gov (United States)

Khosroshahi, Zahra; Kharaziha, Mahshid; Karimzadeh, Fathallah; Allafchian, Alireza

2018-01-01

Graphene, a single layer of sp2-hybridized carbon atoms in a hexagonal (two-dimensional honey-comb) lattice, has attracted strong scientific and technological interest due to its novel and excellent optical, chemical, electrical, mechanical and thermal properties. The solution-processable chemical reduction of Graphene oxide (GO is considered as the most favorable method regarding mass production of graphene. Generally, the reduction of GO is carried out by chemical approaches using different reductants such as hydrazine and sodium borohydride. These components are corrosive, combustible and highly toxic which may be dangerous for personnel health and the environment. Hence, these reducing agents are not promising choice for reducing of graphene oxide (GO). As a consequence, it is necessary for further development and optimization of eco-friendly, natural reducing agent for clean and effective reduction of GO. Ascorbic acid, an eco-friendly and natural reducing agents, having a mild reductive ability and nontoxic property. So, the aim of this research was to green synthesis of GO with ascorbic acid. For this purpose, the required amount of NaOH and ascorbic acid were added to GO solution (0.5 mg/ml) and were heated at 95 °C for 1 hour. According to the X-ray powder diffraction (XRD), scanning electron microscopy (SEM), and electrochemical results, GO were reduced with ascorbic acid like hydrazine with better electrochemical properties and ascorbic acid is an ideal substitute for hydrazine in the reduction of graphene oxide process.

Effect of Vitamin C on Glutathione Peroxidase Activities in Pregnant ...

African Journals Online (AJOL)

Glutathione peroxidase is one of the most important antioxidant enzymes in humans. We studied the relationship between serum glutathione peroxidase activity and vitamin C ingestion during normal pregnancy in women attending antenatal clinic in the University of Ilorin Teaching Hospital, Ilorin. Glutathione peroxidase ...

Salivary ascorbic acid levels in betel quid chewers: A biochemical study.

Science.gov (United States)

Shetty, Shishir R; Babu, Subhas; Kumari, Suchetha; Prasad, Rajendra; Bhat, Supriya; Fazil, K A

2013-07-01

Quid chewing practice has been a part of our tradition since centuries with little known evidence of oral cancer. However, recent trends show a rise in occurrence of oral cancer often associated with tobacco and arecanut usage. Ascorbic acid is an important salivary antioxidant. Betel leaf which is used in quid is known to contain ascorbic acid. The aim of our study was to assess the salivary levels of ascorbic acid in traditional quid chewers so as to determine whether the betel leaf has protective antioxidant action. Salivary ascorbic acid levels of 60 subjects were estimated using the Dinitrophenyl hydrazine method. The results revealed that quid chewers who used betel leaf had higher salivary ascorbic acid content compared to nonbetel leaf quid chewers. This could possibly be due to the protective antioxidants in the betel leaf.

Luffa aegyptiaca (Gourd) Fruit Juice as a Source of Peroxidase

OpenAIRE

Yadav, R. S. S.; Yadav, K. S.; Yadav, H. S.

2011-01-01

Peroxidases have turned out to be potential biocatalyst for a variety of organic reactions. The research work reported in this communication was done with the objective of finding a convenient rich source of peroxidase which could be used as a biocatalyst for organic synthetic reactions. The studies made have shown that Luffa aegyptiaca (gourd) fruit juice contains peroxidase activity of the order of 180 enzyme unit/mL. The K m values of this peroxidase for the substrates guaiacol and hydroge...

CbRCI35, a cold responsive peroxidase from Capsella bursa-pastoris regulates reactive oxygen species homeostasis and enhances cold tolerance in tobacco

Directory of Open Access Journals (Sweden)

Juan Lin

2016-10-01

Full Text Available Low temperature affects gene regulatory networks and alters cellular metabolism to inhibit plant growth. Peroxidases are widely distributed in plants and play a large role in adjusting and controlling reactive oxygen species (ROS homeostasis in response to abiotic stresses such as low temperature. The Rare Cold-Inducible 35 gene from Capsella bursa-pastoris (CbRCI35 belongs to the type III peroxidase family and has been reported to be a cold responsive gene in plants. Here we performed an expressional characterization of CbRCI35 under cold and ionic liquid treatments. The promoter of CbRCI35 was also cloned and its activity was examined using the GUS reporter system. CbRCI35 protein was localized in the cytoplasm according to sequence prediction and GFP fusion assay. Heterologous expression tests revealed that CbRCI35 conferred enhanced resistance to low temperature and activated endogenous cold responsive signaling in tobacco. Furthermore, in the normal condition the ROS accumulation was moderately enhanced while after chilling exposure superoxide dismutase (SOD activity was increased in CbRCI53 transgenic plants. The ROS metabolism related genes expression was altered accordingly. We conclude that CbRCI35 modulates ROS homeostasis and contributes to cold tolerance in plants.

Structural Requirements of Alkylglyceryl-l-Ascorbic Acid Derivatives for Melanogenesis Inhibitory Activity.

Science.gov (United States)

Taira, Norihisa; Katsuyama, Yushi; Yoshioka, Masato; Muraoka, Osamu; Morikawa, Toshio

2018-04-10

l-Ascorbic acid has multifunctional benefits on skin aesthetics, including inhibition of melanin production, and is widely used in cosmetics. It, however, has low stability and poor skin penetration. We hypothesize that alkylglyceryl-l-ascorbic acid derivatives, highly stable vitamin C-alkylglycerol conjugates, would have similar anti-melanogenic activity with better stability and penetration. We test 28 alkylglyceryl-l-ascorbic acid derivatives ( 1 - 28 ) on theophylline-stimulated B16 melanoma 4A5 cells to determine if they inhibit melanogenesis and establish any structure-function relationships. Although not the most potent inhibitors, 3- O -(2,3-dihydroxypropyl)-2- O -hexyl-l-ascorbic acid ( 6 , IC 50 = 81.4 µM) and 2- O -(2,3-dihydroxypropyl)-3- O -hexyl-l-ascorbic acid ( 20 , IC 50 = 117 µM) are deemed the best candidate derivatives based on their inhibitory activities and low toxicities. These derivatives are also found to be more stable than l-ascorbic acid and to have favorable characteristics for skin penetration. The following structural requirements for inhibitory activity of alkylglyceryl-l-ascorbic acid derivatives are also determined: (i) alkylation of glyceryl-l-ascorbic acid is essential for inhibitory activity; (ii) the 3- O -alkyl-derivatives ( 2 - 14 ) exhibit stronger inhibitory activity than the corresponding 2- O -alkyl-derivatives ( 16 - 28 ); and (iii) derivatives with longer alkyl chains have stronger inhibitory activities. Mechanistically, our studies suggest that l-ascorbic acid derivatives exert their effects by suppressing the mRNA expression of tyrosinase and tyrosine-related protein-1.

Effect of ascorbic acid on prevention of hypercholesterolemia induced atherosclerosis.

Science.gov (United States)

Das, S; Ray, R; Snehlata; Das, N; Srivastava, L M

2006-04-01

The notion that oxidation of lipids and propagation of free radicals may contribute to the pathogenesis of atherosclerosis is supported by a large body of evidence. To circumvent the damage caused by oxygen free radicals, antioxidants are needed which provide the much needed neutralization of free radical by allowing the pairing of electrons. In this study we have investigated the effect of ascorbic acid, a water soluble antioxidant on the development of hypercholesterolemia induced atherosclerosis in rabbits. Rabbits were made hypercholesterolemic and atherosclerotic by feeding 100 mg cholesterol/day. Different doses of ascorbic acid were administered to these rabbits. Low dose of ascorbic acid (0.5 mg/100 g body weight/day) did not have any significant effect on the percent of total area covered by atherosclerotic plaque. However, ascorbic acid when fed at a higher dose (15 mg/100 g body weight/day) was highly effective in reducing the atherogenecity. With this dose the percent of total surface area covered by atherosclerotic plaque was significantly less (p ascorbic acid may have great promise in the prevention of hypercholesterolemia induced atherosclerosis.

Gamma radiolysis of aqueous solution of ascorbic acid

International Nuclear Information System (INIS)

Loyola V, V.M.; Azamer B, J.A.; Laviada C, A.; Luna V, P.

1977-01-01

A preliminary study of the gamma radiolysis of a 1.13 x 10 -4 Maqueous solution of ascorbic acid is presented. It was found that dehydroascorbic acid was the principal product at doses of about 75 Krad. An increase in the dehydroascorbic acid concentration rangins from 5 to 40% was obtained, these values depend mainly on the initial ascorbic acid concentration. (author)

Pharmacological ascorbate and ionizing radiation (IR increase labile iron in pancreatic cancer

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Justin C. Moser

2014-01-01

Full Text Available Labile iron, i.e. iron that is weakly bound and is relatively unrestricted in its redox activity, has been implicated in both the pathogenesis as well as treatment of cancer. Two cancer treatments where labile iron may contribute to their mechanism of action are pharmacological ascorbate and ionizing radiation (IR. Pharmacological ascorbate has been shown to have tumor-specific toxic effects due to the formation of hydrogen peroxide. By catalyzing the oxidation of ascorbate, labile iron can enhance the rate of formation of hydrogen peroxide; labile iron can also react with hydrogen peroxide. Here we have investigated the magnitude of the labile iron pool in tumor and normal tissue. We also examined the ability of pharmacological ascorbate and IR to change the size of the labile iron pool. Although a significant amount of labile iron was seen in tumors (MIA PaCa-2 cells in athymic nude mice, higher levels were seen in murine tissues that were not susceptible to pharmacological ascorbate. Pharmacological ascorbate and irradiation were shown to increase the labile iron in tumor homogenates from this murine model of pancreatic cancer. As both IR and pharmacological ascorbate may rely on labile iron for their effects on tumor tissues, our data suggest that pharmacological ascorbate could be used as a radio-sensitizing agent for some radio-resistant tumors.

Ascorbic acid enables reversible dopamine receptor 3H-agonist binding

International Nuclear Information System (INIS)

Leff, S.; Sibley, D.R.; Hamblin, M.; Creese, I.

1981-01-01

The effects of ascorbic acid on dopaminergic 3 H-agonist receptor binding were studied in membrane homogenates of bovine anterior pituitary and caudate, and rat striatum. In all tissues virtually no stereospecific binding (defined using 1uM (+)butaclamol) of the 3 H-agonists N-propylnorapomorphine (NPA), apomorphine, or dopamine could be demonstrated in the absence of ascorbic acid. Although levels of total 3 H-agonist binding were three to five times greater in the absence than in the presence of 0.1% ascorbic acid, the increased binding was entirely non-stereospecific. Greater amounts of dopamine-inhibitable 3 H-NPA binding could be demonstrated in the absence of 0.1% ascorbic acid, but this measure of ''specific binding'' was demonstrated not to represent dopamine receptor binding since several other catecholamines and catechol were equipotent with dopamine and more potent than the dopamine agonist (+/-)amino-6,7-dihydroxy-1,2,3,4-tetrahydronapthalene (ADTN) in inhibiting this binding. High levels of dopamine-displaceable 3 H-agonist binding were detected in fresh and boiled homogenates of cerebellum, an area of brain which receives no dopaminergic innervation, further demonstrating the non-specific nature of 3 H-agonist binding in the absence of ascorbic acid. These studies emphasize that under typical assay conditions ascorbic acid is required in order to demonstrate reversible and specific 3 H-agonist binding to dopamine receptors

Interrelationship of dietary lipids and ascorbic acid with hepatic enzymes of cholesterol metabolic pathway.

Science.gov (United States)

Sen, S; Mukherjee, S

1997-01-01

Effect of unsaturated and saturated fats on cholesterol metabolism was studied in ascorbate sufficient and deficient guineapigs. Experimental animals were made chronic ascorbic acid deficient by allowing oral intake of 0.5 mg ascorbic acid/day/animal. Elevation in serum and liver cholesterol and triglyceride along with depression in cholesterol oxidation and 7 alpha-hydroxylation in liver was observed in unsaturated fat fed guineapigs with ascorbate deficiency. Liver microsomal cytochrome P-450 level was found to be low in ascorbate deficient animals. Polyunsaturated fat intake could not lower the serum cholesterol level in ascorbate deficiency. Today polyunsaturated fat in the diet is encouraged all over the world for its hypocholesterolemic effect. This study indicates that polyunsaturated fat intake with ascorbic acid deficiency may produce hypercholesterolemia.

Neutron scattering and HPLC study on L-ascorbic acid and its degradation

International Nuclear Information System (INIS)

Bellocco, E.; Barreca, D.; Lagana, G.; Leuzzi, U.; Migliardo, F.; Torre, R. La; Galli, G.; Galtieri, A.; Minutoli, L.; Squadrito, F.

2008-01-01

The present paper shows a systematic dynamic and kinetic study on L-ascorbic acid and its degradation at high temperature. The neutron scattering study allows, through the behavior of quasi-elastic neutron scattering (QENS) spectra, to characterize the diffusive dynamics of L-ascorbic acid in water mixtures. Ascorbic acid undergoes degradation process at high temperature, but the presence of trehalose in solution markedly avoids ascorbic acid loss enhancing its t 1/2 (half life time), as determined by high performance liquid chromatography (HPLC)

Ascorbic acid attenuates endothelial permeability triggered by cell-free hemoglobin.

Science.gov (United States)

Kuck, Jamie L; Bastarache, Julie A; Shaver, Ciara M; Fessel, Joshua P; Dikalov, Sergey I; May, James M; Ware, Lorraine B

2018-01-01

Increased endothelial permeability is central to shock and organ dysfunction in sepsis but therapeutics targeted to known mediators of increased endothelial permeability have been unsuccessful in patient studies. We previously reported that cell-free hemoglobin (CFH) is elevated in the majority of patients with sepsis and is associated with organ dysfunction, poor clinical outcomes and elevated markers of oxidant injury. Others have shown that Vitamin C (ascorbate) may have endothelial protective effects in sepsis. In this study, we tested the hypothesis that high levels of CFH, as seen in the circulation of patients with sepsis, disrupt endothelial barrier integrity. Human umbilical vein endothelial cells (HUVEC) were grown to confluence and treated with CFH with or without ascorbate. Monolayer permeability was measured by Electric Cell-substrate Impedance Sensing (ECIS) or transfer of 14 C-inulin. Viability was measured by trypan blue exclusion. Intracellular ascorbate was measured by HPLC. CFH increased permeability in a dose- and time-dependent manner with 1 mg/ml of CFH increasing inulin transfer by 50% without affecting cell viability. CFH (1 mg/ml) also caused a dramatic reduction in intracellular ascorbate in the same time frame (1.4 mM without CFH, 0.23 mM 18 h after 1 mg/ml CFH, p < 0.05). Pre-treatment of HUVECs with ascorbate attenuated CFH induced permeability. CFH increases endothelial permeability in part through depletion of intracellular ascorbate. Supplementation of ascorbate can attenuate increases in permeability mediated by CFH suggesting a possible therapeutic approach in sepsis. Copyright © 2017 Elsevier Inc. All rights reserved.

Salivary ascorbic acid levels in betel quid chewers: A biochemical study

Directory of Open Access Journals (Sweden)

Shishir R Shetty

2013-01-01

Full Text Available Background: Quid chewing practice has been a part of our tradition since centuries with little known evidence of oral cancer. However, recent trends show a rise in occurrence of oral cancer often associated with tobacco and arecanut usage. Ascorbic acid is an important salivary antioxidant. Betel leaf which is used in quid is known to contain ascorbic acid. Aim: The aim of our study was to assess the salivary levels of ascorbic acid in traditional quid chewers so as to determine whether the betel leaf has protective antioxidant action. Materials and Methods: Salivary ascorbic acid levels of 60 subjects were estimated using the Dinitrophenyl hydrazine method. Results: The results revealed that quid chewers who used betel leaf had higher salivary ascorbic acid content compared to nonbetel leaf quid chewers. This could possibly be due to the protective antioxidants in the betel leaf.

Studies of peroxidase isozyme profile in mungbean mutants

International Nuclear Information System (INIS)

Auti, S.G.; Apparao, B.J.

2007-01-01

Peroxidase is an important oxygen-scavenging enzyme. The activity of peroxidase is often correlated with growth, development and hormonal activity. Traditional methods of cultivar identification usually involve observation and recording of morphological characters or description such as yield, height, weight, earliness etc. which vary with environmental conditions and often misleading. So molecular markers like protein and isozymes profiles, RFLP, RAPDs markers etc. are widely employed in varietal identification of cultivars. It plays important role in respiration and is an indicator of oxidative status of plants. Electrophoretic techniques have been used to group species and identify cultivars. Such identification has various advantages including the unique pattern of protein or isozymes bands for each pure cultivar under any set of environmental conditions. Peroxidase isozyme serves as very good marker for any mutational studies. In the present investigation, peroxidase isozyme profiles of various mutants of mungbean was studied employing the technique of electrophoresis

Neutron scattering and HPLC study on L-ascorbic acid and its degradation

Energy Technology Data Exchange (ETDEWEB)

Bellocco, E. [Department of Organic and Biological Chemistry, University of Messina, Messina (Italy)], E-mail: bellocco@isengard.unime.it; Barreca, D.; Lagana, G.; Leuzzi, U. [Department of Organic and Biological Chemistry, University of Messina, Messina (Italy); Migliardo, F.; Torre, R. La; Galli, G. [Department of Physics, University of Messina, Messina (Italy); Galtieri, A. [Department of Organic and Biological Chemistry, University of Messina, Messina (Italy); Minutoli, L.; Squadrito, F. [Department of Clinical and Experimental Medicine and Pharmacology, University of Messina, Messina (Italy)

2008-04-18

The present paper shows a systematic dynamic and kinetic study on L-ascorbic acid and its degradation at high temperature. The neutron scattering study allows, through the behavior of quasi-elastic neutron scattering (QENS) spectra, to characterize the diffusive dynamics of L-ascorbic acid in water mixtures. Ascorbic acid undergoes degradation process at high temperature, but the presence of trehalose in solution markedly avoids ascorbic acid loss enhancing its t{sub 1/2} (half life time), as determined by high performance liquid chromatography (HPLC)

Luffa aegyptiaca (Gourd) Fruit Juice as a Source of Peroxidase.

Science.gov (United States)

Yadav, R S S; Yadav, K S; Yadav, H S

2011-01-01

Peroxidases have turned out to be potential biocatalyst for a variety of organic reactions. The research work reported in this communication was done with the objective of finding a convenient rich source of peroxidase which could be used as a biocatalyst for organic synthetic reactions. The studies made have shown that Luffa aegyptiaca (gourd) fruit juice contains peroxidase activity of the order of 180 enzyme unit/mL. The K(m) values of this peroxidase for the substrates guaiacol and hydrogen peroxide were 2.0 and 0.2 mM, respectively. The pH and temperature optima were 6.5 and 60°C, respectively. Like other peroxidases, it followed double displacement type mechanism. Sodium azide inhibited the enzyme competitively with K(i) value of 3.35 mM.

Luffa aegyptiaca (Gourd Fruit Juice as a Source of Peroxidase

Directory of Open Access Journals (Sweden)

R. S. S. Yadav

2011-01-01

Full Text Available Peroxidases have turned out to be potential biocatalyst for a variety of organic reactions. The research work reported in this communication was done with the objective of finding a convenient rich source of peroxidase which could be used as a biocatalyst for organic synthetic reactions. The studies made have shown that Luffa aegyptiaca (gourd fruit juice contains peroxidase activity of the order of 180 enzyme unit/mL. The Km values of this peroxidase for the substrates guaiacol and hydrogen peroxide were 2.0 and 0.2 mM, respectively. The pH and temperature optima were 6.5 and 60°C, respectively. Like other peroxidases, it followed double displacement type mechanism. Sodium azide inhibited the enzyme competitively with Ki value of 3.35 mM.

Aortic wall damage in mice unable to synthesize ascorbic acid

OpenAIRE

Maeda, Nobuyo; Hagihara, Hiroyuki; Nakata, Yukiko; Hiller, Sylvia; Wilder, Jennifer; Reddick, Robert

2000-01-01

By inactivating the gene for l-gulono-γ-lactone oxidase, a key enzyme in ascorbic acid synthesis, we have generated mice that, like humans, depend on dietary vitamin C. Regular chow, containing about 110 mg/kg of vitamin C, is unable to support the growth of the mutant mice, which require l-ascorbic acid supplemented in their drinking water (330 mg/liter). Upon withdrawal of supplementation, plasma and tissue ascorbic acid levels decreased to 10–15% of normal within 2 weeks, and after 5 weeks...

Self-Assembled Complexes of Horseradish Peroxidase with Magnetic Nanoparticles Showing Enhanced Peroxidase Activity

KAUST Repository

Corgié , Sté phane C.; Kahawong, Patarawan; Duan, Xiaonan; Bowser, Daniel; Edward, Joseph B.; Walker, Larry P.; Giannelis, Emmanuel P.

2012-01-01

Bio-nanocatalysts (BNCs) consisting of horseradish peroxidase (HRP) self-assembled with magnetic nanoparticles (MNPs) enhance enzymatic activity due to the faster turnover and lower inhibition of the enzyme. The size and magnetization of the MNPs

SUPEROxIDE DISMUTASE AS A COMPONENT OF ANTIOxIDANT THERAPY: CURRENT STATE OF THE ISSUE AND PROSPECTS. A LITERATURE REVIEW

Directory of Open Access Journals (Sweden)

T. A. Pushkina

2016-01-01

Full Text Available Oxidative stress, developing in many diseases, is an imbalance between pro-oxidants and antioxidant defense mechanisms of the body. Antioxidant enzymes such as superoxide dismutase (SOD play a key role in reduction of oxidative stress in vivo. Thus, a decrease in formation of reactive oxygen species (ROS, as well as activation of lipid peroxidation (LPO due to exogenous SOD intake could be an effective method of prevention and treatment of some diseases. In this paper, we provide an overview of the results of experimental and clinical studies on the use of intravenous drugs and dietary supplements, containing SOD, in the treatment of inflammatory, infectious, cardiovascular and neurodegenerative diseases. As a result of SOD administration, the majority of authors observed an increase in the content of endogenous antioxidant enzymes (SOD, catalase, glutathione peroxidase, i.e., stimulation of endogenous antioxidant defence and consequent reduction of oxidative stress, which may explain mechanisms of positive effects observed.

The effect of bicarbonate on menadione-induced redox cycling and cytotoxicity: potential involvement of the carbonate radical.

Science.gov (United States)

Aljuhani, Naif; Michail, Karim; Karapetyan, Zubeida; Siraki, Arno G

2013-10-01

We have investigated the effect of NaHCO3 on menadione redox cycling and cytotoxicity. A cell-free system utilized menadione and ascorbic acid to catalyze a redox cycle, and we utilized murine hepatoma (Hepa 1c1c7) cells for in vitro experiments. Experiments were performed using low (2 mmol/L) and physiological (25 mmol/L) levels of NaHCO3 in buffer equilibrated to physiological pH. Using oximetry, ascorbic acid oxidation, and ascorbyl radical detection, we found that menadione redox cycling was enhanced by NaHCO3. Furthermore, Hepa 1c1c7 cells treated with menadione demonstrated cytotoxicity that was significantly increased with physiological concentrations of NaHCO3 in the media, compared with low levels of NaHCO3. Interestingly, the inhibition of superoxide dismutase (SOD) with 2 different metal chelators was associated with a protective effect against menadione cytotoxicity. Using isolated protein, we found a significant increase in protein carbonyls with menadione-ascorbate-SOD with physiological NaHCO3 levels; low NaHCO3 or SOD-free reactions produced lower levels of protein carbonyls. In conclusion, these findings suggest that the hydrogen peroxide generated by menadione redox cycling together with NaHCO3-CO2 are potential substrates for SOD peroxidase activity that can lead to carbonate-radical-enhanced cytotoxicity. These findings demonstrate the importance of NaHCO3 in menadione redox cycling and cytotoxicity.

Ascorbate oxidase-dependent changes in the redox state of the apoplast modulate gene transcript accumulation leading to modified hormone signaling and orchestration of defense processes in tobacco.

Science.gov (United States)

Pignocchi, Cristina; Kiddle, Guy; Hernández, Iker; Foster, Simon J; Asensi, Amparo; Taybi, Tahar; Barnes, Jeremy; Foyer, Christine H

2006-06-01

The role of the redox state of the apoplast in hormone responses, signaling cascades, and gene expression was studied in transgenic tobacco (Nicotiana tabacum) plants with modified cell wall-localized ascorbate oxidase (AO). High AO activity specifically decreased the ascorbic acid (AA) content of the apoplast and altered plant growth responses triggered by hormones. Auxin stimulated shoot growth only when the apoplastic AA pool was reduced in wild-type or AO antisense lines. Oxidation of apoplastic AA in AO sense lines was associated with loss of the auxin response, higher mitogen-activated protein kinase activities, and susceptibility to a virulent strain of the pathogen Pseudomonas syringae. The total leaf glutathione pool, the ratio of reduced glutathione to glutathione disulfide, and glutathione reductase activities were similar in the leaves of all lines. However, AO sense leaves exhibited significantly lower dehydroascorbate reductase and ascorbate peroxidase activities than wild-type and antisense leaves. The abundance of mRNAs encoding antioxidant enzymes was similar in all lines. However, the day/night rhythms in the abundance of transcripts encoding the three catalase isoforms were changed in response to the AA content of the apoplast. Other transcripts influenced by AO included photorespiratory genes and a plasma membrane Ca(2+) channel-associated gene. We conclude that the redox state of the apoplast modulates plant growth and defense responses by regulating signal transduction cascades and gene expression patterns. Hence, AO activity, which modulates the redox state of the apoplastic AA pool, strongly influences the responses of plant cells to external and internal stimuli.

Bioaccumulation of heavy metals and ecophysiological responses to heavy metal stress in selected populations of Vaccinium myrtillus L. and Vaccinium vitis-idaea L.

Science.gov (United States)

Kandziora-Ciupa, Marta; Nadgórska-Socha, Aleksandra; Barczyk, Gabriela; Ciepał, Ryszard

2017-09-01

The aim of this study was to determine the concentrations of heavy metals (Cd, Pb, Zn, Fe, and Mn) in soil, and their bioavailability and bioaccumulation in Vaccinium myrtillus L. and Vaccinium vitis-idaea L. organs. Analysis also concerned the physiological responses of these plants from three polluted sites (immediate vicinity of a zinc smelter in Miasteczko Śląskie, ArcelorMittal Poland S.A. iron smelter in Dąbrowa Górnicza-Łosień, and Jaworzno III power plant in Jaworzno) and one pseudo-control site (Pazurek nature reserve in Jaroszowiec Olkuski). All of the sites are situated in the southern parts of Poland in the Śląskie or Małopolskie provinces. The contents of proline, non-protein thiols, glutathione, ascorbic acid, and the activity of superoxide dismutase and guaiacol peroxidase in the leaves of Vaccinium myrtillus L. and Vaccinium vitis-idaea L. were measured. In soil, the highest levels of Cd, Pb, and Zn (HNO 3 extracted and CaCl 2 extracted) were detected at the Miasteczko Śląskie site. At all sites a several times lower concentration of the examined metals was determined in the fraction of soil extracted with CaCl 2 . Much higher Cd, Pb, Zn and Fe concentrations were found in V. myrtillus and V. vitis-idaea grown at the most polluted site (located near the zinc smelter) in comparison with cleaner areas; definitely higher bioaccumulation of these metals was found in lingonberry organs. Additionally, we observed a large capability of bilberry to accumulate Mn. Antioxidant response to heavy metal stress also differed between V. myrtillus and V. vitis-idaea. In V. myrtillus we found a positive correlation between the level of non-protein thiols and Cd and Zn concentrations, and also between proline and these metals. In V. vitis-idaea leaves an upward trend in ascorbic acid content and superoxide dismutase activity accompanied an increase in Cd, Pb, and Zn concentrations. At the same time, the increased levels of all tested metals in the leaves

Old Things New View: Ascorbic Acid Protects the Brain in Neurodegenerative Disorders

Directory of Open Access Journals (Sweden)

Adriana Covarrubias-Pinto

2015-11-01

Full Text Available Ascorbic acid is a key antioxidant of the Central Nervous System (CNS. Under brain activity, ascorbic acid is released from glial reservoirs to the synaptic cleft, where it is taken up by neurons. In neurons, ascorbic acid scavenges reactive oxygen species (ROS generated during synaptic activity and neuronal metabolism where it is then oxidized to dehydroascorbic acid and released into the extracellular space, where it can be recycled by astrocytes. Other intrinsic properties of ascorbic acid, beyond acting as an antioxidant, are important in its role as a key molecule of the CNS. Ascorbic acid can switch neuronal metabolism from glucose consumption to uptake and use of lactate as a metabolic substrate to sustain synaptic activity. Multiple evidence links oxidative stress with neurodegeneration, positioning redox imbalance and ROS as a cause of neurodegeneration. In this review, we focus on ascorbic acid homeostasis, its functions, how it is used by neurons and recycled to ensure antioxidant supply during synaptic activity and how this antioxidant is dysregulated in neurodegenerative disorders.

Peroxidase isozyme profiles in some sweet cherry rootstocks and ...

African Journals Online (AJOL)

PERS

2012-01-10

, 2005). Santamour (1980) defined role of peroxidase in graft compatibility as; 1) lignification is essential for a strong and permanent graft union; 2) peroxidase isoenzymes mediate the polymeri- zation of cinnamic alcohols to ...

Mechanisms of metal tolerance in marine macroalgae, with emphasis on copper tolerance in Chlorophyta and Rhodophyta.

Science.gov (United States)

Moenne, Alejandra; González, Alberto; Sáez, Claudio A

2016-07-01

Green and red macroalgae are closely related organisms, and with terrestrial plants, and constitute the base of marine food webs in coastal ecosystems. Green and red seaweeds, as all living organisms, require essential metals, such as copper, iron, zinc, which can act as co-factors for several proteins and enzymes; however, these metals in excess can induce stress and impair cell viability. Most important negative effects of metal excess are related to the induction of an oxidative stress condition, characterized by the over-accumulation of Reactive Oxygen Species (ROS). In this respect, copper, abundant in wastewaters disposed to coastal environments from domestic and industrial activities, has been one of the most studied metals. Different investigations have provided evidence that green and red macroalgae display several defenses against copper excess to prevent, or at least reduce, stress and damage, among which are cellular exclusion mechanisms, synthesis of metal-chelating compounds, and the activation of the antioxidant system. Most important defense mechanisms identified in green and red seaweed involve: metal-binding to cell wall and epibionts; syntheses of metallothioneins and phytochelatins that accumulate in the cytoplasm; and the increase in the activity of antioxidant enzymes such as superoxide dismutase, ascorbate peroxidase, glutathione peroxidase and catalase, and greater production of antioxidant metabolites as glutathione and ascorbate in organelles and the cytoplasm. In this review, we go through historical records, latest advances, and pending tasks aiming to expand our current knowledge on defense mechanisms to copper excess in green and red macroalgae, with emphasis on biochemical and molecular aspects. Copyright © 2016 Elsevier B.V. All rights reserved.

Indole-3-butyric acid mediates antioxidative defense systems to promote adventitious rooting in mung bean seedlings under cadmium and drought stresses.

Science.gov (United States)

Li, Shi-Weng; Zeng, Xiao-Ying; Leng, Yan; Feng, Lin; Kang, Xiao-Hu

2018-06-08

In vitro experiments were performed to determine whether auxin can mediate the formation of adventitious roots in response to heavy metal and drought stresses using a model rooting plant, mung bean [Vigna radiata (L.) Wilczek]. The treatments with CdCl 2 or mannitol alone significantly inhibited the formation and growth of adventitious roots in mung bean seedlings. In contrast, when CdCl 2 or mannitol was applied together with indole-3-butyric acid (IBA), IBA considerably cancelled the inhibition of adventitious rooting by stresses. Treatment with CdCl 2 or mannitol alone significantly increased the soluble protein and malondialdehyde (MDA) contents. CdCl 2 and mannitol stress each induced differentially significant changes in the activities of antioxidative enzyme and antioxidant levels during adventitious rooting. Notably, both CdCl 2 and mannitol stress strongly reduced the peroxidase (POD) and ascorbate peroxidase (APX) activities and glutathione (GSH) and phenols levels. Catalase and superoxide dismutase (SOD) activity were enhanced by CdCl 2 but reduced by mannitol. CdCl 2 increased the ascorbate acid (ASA) level, which was decreased by mannitol. Furthermore, when CdCl 2 or mannitol was applied together with IBA, IBA counteracted the CdCl 2 - or mannitol-induced increase or decrease in certain antioxidants, MDA, and antioxidative enzymes. These results suggest that Cd and mannitol stress inhibition of adventitious rooting is associated with the regulation of antioxidative enzymes and antioxidants in cells to defense the oxidative stress. Moreover, IBA alleviates the effects of Cd and mannitol stress on the rooting process partially through the regulation of antioxidative defense systems. Copyright © 2018 Elsevier Inc. All rights reserved.

Mercury induced oxidative stress, DNA damage, and activation of antioxidative system and Hsp70 induction in duckweed (Lemna minor).

Science.gov (United States)

Zhang, Tingting; Lu, Qianqian; Su, Chunlei; Yang, Yaru; Hu, Dan; Xu, Qinsong

2017-09-01

Mercury uptake and its effects on physiology, biochemistry and genomic stability were investigated in Lemna minor after 2 and 6d of exposure to 0-30μM Hg. The accumulation of Hg increased in a concentration- and duration-dependent manner, and was positively correlated with the leaf damage. Oxidative stress after Hg exposure was evidenced in L. minor by a significant decrease in photosynthetic pigments, an increase in malondialdehyde and lipoxygenase activities (total enzyme activity and isoenzymes activity). Fronds of L. minor exposed to Hg showed an induction of peroxidase, catalase, and ascorbate peroxidase activities (total enzyme activity and some isoenzymes activities). Exposure of L. minor to Hg reduced the activity (total enzyme activity and some isoenzymes activities) of glutathione reductase, and superoxide dismutase. Exposure to Hg produced a transient increase in the content of glutathione and ascorbic acid. The content of dehydroascorbate and oxidized glutathione in L. minor were high during the entire exposure period. Exposure of L. minor to Hg also caused the accumulation of proline and soluble sugars. The amplification of new bands and the absence of normal DNA amplicons in treated plants in the random amplified polymorphic DNA (RAPD) profile indicated that genomic template stability (GTS) was affected by Hg treatment. The accumulation of Hsp70 indicated the occurrence of a heat shock response at all Hg concentrations. These results suggest that L. minor plants were able to cope with Hg toxicity through the activation of various mechanisms involving enzymatic and non-enzymatic antioxidants, up-regulation of proline, and induction of Hsp70. Copyright © 2017 Elsevier Inc. All rights reserved.

Effect of ascorbate ions in DTPA treatment after contamination by mixed plutonium dioxide-sodium burning products

International Nuclear Information System (INIS)

Metivier, H.; Masse, R.; Nolibe, D.; Nenot, J.C.; Lafuma, J.

1977-01-01

Plutonium toxicity problems arising from the use of molten sodium cooled fast breeder reactors involving the accidental mixing and ignition of sodium contaminated by plutonium dioxide have been investigated. The possibility of using the strong reducing agent, ascorbate ion, in order to reduce Pu VI to a chemical form more complexable by DTPA, has been tested using male and female rats. Urine, feces, liver and skeletal measurements of 239 Pu daughter products were carried out. It was shown that the transportable fraction was not significantly modified by the associate ascorbate-DTPA treatment. However the skeletal burden which represents 2.2% with DTPA, reached only 1.6% with ascorbate association and 0.3% with preventive ascorbate injections. Whatever the DTPA ascorbate treatment, the liver burden was not modified significantly. Difference observable only with preventive ascorbate treatment cancels out ascorbate association in order to greatly increase DTPA therapy efficiency, but seems to indicate that the Pu-proteins associations in blood is reduced more easily by ascorbate than association of Pu with local proteins. Ascorbate reduction can also be observed in urinary elimination in that preventive ascorbate, followed by DTPA-ascorbate, leads to a quicker urinary elimination than DTPA or DTPA plus ascorbate post treatment. (U.K.)

Effect of supplemental Ascorbic acid and disturbance stress on the ...

African Journals Online (AJOL)

Effect of supplemental Ascorbic acid and disturbance stress on the performance of broiler chickens. ... Nigerian Journal of Animal Production ... Results showed that there were no significant interactions between dietary ascorbic acid supplementation and disturbance stress levels on any of the performance data considered.

Modelling of thermal degradation kinetics of ascorbic acid in ...

African Journals Online (AJOL)

Ascorbic acid (vitamin C) loss in thermally treated pawpaw and potato was modelled mathematically. Isothermal experiments in the temperature range of 50 -80 oC for the drying of pawpaw and 60 -100 oC for the blanch-drying of potato were utilized to determine the kinetics of ascorbic acid loss in both fruit and vegetable.

Changes in Oxidative Stress Markers and Biological Markers of Muscle Injury with Aging at Rest and in Response to an Exhaustive Exercise

Science.gov (United States)

Bouzid, Mohamed Amine; Hammouda, Omar; Matran, Regis; Robin, Sophie; Fabre, Claudine

2014-01-01

Purpose The aim of this study was to evaluate whether oxidative stress markers and biomarkers of muscle injury would be affected by aging at rest and in response to an incremental exhaustive exercise. Methods Fifteen young (20.3±2.8 years) and fifteen older adults (65.1±3.5 years) performed an incremental cycle ergometer test to exhaustion. Before and after exercise, oxidative stress [superoxide dismutase (SOD), glutathione peroxidase (GPX), glutathione reductase (GR), ascorbic acid, α-Tocopherol, malondialdehyde (MDA)] and muscle injury [creatine kinase (CK), lactate deshydrogenase (LDH)] biomarkers were assessed. Results At rest, there was no difference in oxidative stress markers and LDH level between the groups, however CK was significantly higher in the young group than the elderly group (pantioxidant efficiency and an increase in oxidative stress damage. Furthermore, older adults would not more susceptible to exercise-induced muscle injury than young people. PMID:24618679

High Dose Ascorbate Causes Both Genotoxic and Metabolic Stress in Glioma Cells

Science.gov (United States)

Castro, Maria Leticia; Carson, Georgia M.; McConnell, Melanie J.; Herst, Patries M.

2017-01-01

We have previously shown that exposure to high dose ascorbate causes double stranded breaks (DSBs) and a build-up in S-phase in glioblastoma (GBM) cell lines. Here we investigated whether or not this was due to genotoxic stress as well as metabolic stress generated by exposure to high dose ascorbate, radiation, ascorbate plus radiation and H2O2 in established and primary GBM cell lines. Genotoxic stress was measured as phosphorylation of the variant histone protein, H2AX, 8-oxo-7,8-dihydroguanine (8OH-dG) positive cells and cells with comet tails. Metabolic stress was measured as a decrease in NADH flux, mitochondrial membrane potential (by CMXRos), ATP levels (by ATP luminescence) and mitochondrial superoxide production (by mitoSOX). High dose ascorbate, ascorbate plus radiation, and H2O2 treatments induced both genotoxic and metabolic stress. Exposure to high dose ascorbate blocked DNA synthesis in both DNA damaged and undamaged cell of ascorbate sensitive GBM cell lines. H2O2 treatment blocked DNA synthesis in all cell lines with and without DNA damage. DNA synthesis arrest in cells with damaged DNA is likely due to both genotoxic and metabolic stress. However, arrest in DNA synthesis in cells with undamaged DNA is likely due to oxidative damage to components of the mitochondrial energy metabolism pathway. PMID:28737676

Incorporation of carbohydrate residues into peroxidase isoenzymes in horseradish roots.

Science.gov (United States)

Lew, J Y; Shannon, L M

1973-11-01

Sliced root tissue of the horseradish plant (Armoracia rusticana), when incubated with mannose-U-(14)C, incorporated radioactivity into peroxidase isoenzymes. Over 90% of the radioactivity in the highly purified peroxidase isoenzymes was present in the neutral sugar residues of the molecule, i.e. fucose, arabinose, xylose, mannose. When the root slices were incubated simultaneously with leucine-4,5-(3)H and mannose-U-(14)C, cycloheximide strongly inhibited leucine incorporation into the peptide portion of peroxidase isoenzymes but had little effect on the incorporation of (14)C into the neutral sugars. These results indicated that synthesis of the peptide portion of peroxidase was completed before the monosaccharide residues were attached to the molecule. This temporal relationship between the synthesis of protein and the attachment of carbohydrate residues in the plant glycoprotein, horseradish peroxidase, appears to be similar to that reported for glycoprotein biosynthesis in many mammalian systems.

Arabidopsis ATP A2 peroxidase. Expression and high-resolution structure of a plant peroxidase with implications for lignification

DEFF Research Database (Denmark)

Ostergaard, L; Teilum, K; Mirza, O

2000-01-01

Lignins are phenolic biopolymers synthesized by terrestrial, vascular plants for mechanical support and in response to pathogen attack. Peroxidases have been proposed to catalyse the dehydrogenative polymerization of monolignols into lignins, although no specific isoenzyme has been shown...... to be involved in lignin biosynthesis. Recently we isolated an extracellular anionic peroxidase, ATP A2, from rapidly lignifying Arabidopsis cell suspension culture and cloned its cDNA. Here we show that the Atp A2 promoter directs GUS reporter gene expression in lignified tissues of transgenic plants. Moreover......-coumaryl and coniferyl alcohols are preferred by ATP A2, while the oxidation of sinapyl alcohol will be sterically hindered in ATP A2 as well as in all other plant peroxidases due to an overlap with the conserved Pro-139. We suggest ATP A2 is involved in a complex regulation of the covalent cross-linking in the plant...

Studies on the biological oxidation - The oxidation of ascorbic acid (vitamin C) in biological fluids

OpenAIRE

Guzmán Barrón, E. S.; Guzmán Barrón, Alberto; Klemperer, Friedrich

2014-01-01

Biological fluids can be divided according to their behavior toward ascorbic acid into two groups: those having an inhibitory mechanism that protects the ascorbic acid oxidation, and those lacking this mechanism. Animal fluids and some of vegetable origin (those containing dosables amounts of ascorbic acid) corresponding to the first group. Ascorbic acid is protected from oxidation in the fluids by the action of copper catalyst. Fluids from plants (those that contain very little ascorbic acid...

Effect of docosahexaenoic acid and ascorbate on peroxidation of retinal membranes of ODS rats.

Science.gov (United States)

Wang, Jin-Ye; Sekine, Seiji; Saito, Morio

2003-04-01

Mutant male osteogenic disorder Shionogi (ODS) rats, unable to synthesize ascorbic acid, were fed diets containing a high content of docosahexaenoic acid (DHA) and different amounts of ascorbic acid, to study the effect of DHA on peroxidative susceptibility of the retina and possible antioxidant action of ascorbic acid. ODS rats were fed from 7 weeks of age with diets containing high DHA (6.4% of total energy). A control group received a diet high in linoleic acid. The diets also contained varying amounts of ascorbic acid. Fatty acid compositions and phospholipid hydroperoxides in rod outer segment (ROS) membranes, and retinal ascorbic acid were analyzed. DHA in ROS membranes was significantly increased in rats fed high DHA, compared with the linoleic acid diet. Levels of phospholipid hydroperoxides in the DHA-fed rats were significantly higher than the linoleic acid-fed rats. Ascorbic acid supplementation did not suppress the phospholipid hydroperoxide levels after a high DHA diet, even when the supplement increased the content of retinal ascorbic acid. In conclusion, high DHA feeding induced a marked increase of phospholipid hydroperoxides in ROS membranes of ODS rats. Supplementation of ascorbic acid did not reverse this increase.

Extracellular ascorbate stabilization as a result of transplasma electron transfer in Saccharomyces cerevisiae.

Science.gov (United States)

Santos-Ocaña, C; Navas, P; Crane, F L; Córdoba, F

1995-12-01

The presence of yeast cells in the incubation medium prevents the oxidation of ascrobate catalyzed by copper ions. Ethanol increases ascorbate retention. Pyrazole, an alcohol dehydrogenase inhibitor, prevents ascorbate stabilization by cells. Chelation of copper ions does not account for stabilization, since oxidation rates with broken or boiled cells or conditioned media are similar to control rates in the absence of cells. Protoplast integrity is needed to reach optimal values of stabilization. Chloroquine, a known inhibitor of plasma membrane redox systems, inhibits the ascorbate stabilization, the inhibition being partially reversed by coenzyme Q6. Chloroquine does not inhibit ferricyanide reduction. Growth of yeast in iron-deficient media to increase ferric ion reductase activity also increases the stabilization. In conclusion, extracellular ascorbate stabilization by yeast cells can reflect a coenzyme Q dependent transplasmalemma electron transfer which uses NADH as electron donor. Iron deficiency increases the ascorbate stabilization but the transmembrane ferricyanide reduction system can act independently of ascorbate stabilization.

Sequence and RT-PCR expression analysis of two peroxidases from Arabidopsis thaliana belonging to a novel evolutionary branch of plant peroxidases.

Science.gov (United States)

Kjaersgård, I V; Jespersen, H M; Rasmussen, S K; Welinder, K G

1997-03-01

cDNA clones encoding two new Arabidopsis thaliana peroxidases, ATP 1a and ATP 2a, have been identified by searching the Arabidopsis database of expressed sequence tags (dbEST). They represent a novel branch of hitherto uncharacterized plant peroxidases which is only 35% identical in amino acid sequence to the well characterized group of basic plant peroxidases represented by the horseradish (Armoracia rusticana) isoperoxidases HRP C, HRP E5 and the similar Arabidopsis isoperoxidases ATP Ca, ATP Cb, and ATP Ea. However ATP 1a is 87% identical in amino acid sequence to a peroxidase encoded by an mRNA isolated from cotton (Gossypium hirsutum). As cotton and Arabidopsis belong to rather diverse families (Malvaceae and Crucifereae, respectively), in contrast with Arabidopsis and horseradish (both Crucifereae), the high degree of sequence identity indicates that this novel type of peroxidase, albeit of unknown function, is likely to be widespread in plant species. The atp 1 and atp 2 types of cDNA sequences were the most redundant among the 28 different isoperoxidases identified among about 200 peroxidase encoding ESTs. Interestingly, 8 out of totally 38 EST sequences coding for ATP 1 showed three identical nucleotide substitutions. This variant form is designated ATP 1b. Similarly, six out of totally 16 EST sequences coding for ATP 2 showed a number of deletions and nucleotide changes. This variant form is designated ATP 2b. The selected EST clones are full-length and contain coding regions of 993 nucleotides for atp 1a, and 984 nucleotides for atp 2a. These regions show 61% DNA sequence identity. The predicted mature proteins ATP 1a, and ATP 2a are 57% identical in sequence and contain the structurally and functionally important residues, characteristic of the plant peroxidase superfamily. However, they do show two differences of importance to peroxidase catalysis: (1) the asparagine residue linked with the active site distal histidine via hydrogen bonding is absent

Combined effects of Psoralens and ultraviolet-B on growth, pigmentation and biochemical parameters of Abelmoschus esculentus L.

Science.gov (United States)

Kumari, Rima; Singh, Suruchi; Agrawal, S B

2009-05-01

The effects of pre-treatment of Psoralens (furocoumarin compounds) and supplemental ultraviolet-B (sUV-B) were studied on plant growth, photosynthetic and non-photosynthetic pigments, protein, phenylalanine ammonia lyase (PAL) activity and antioxidative defense potential as well as their ultimate effects on biomass production in Abelmoschus esculentus L. (Okra) plants. Psoralens are capable of absorbing radiant energy and stimulating the pigmentation of human skin when photo-activated in presence of UV-A or UV-B making them beneficial in the treatment of vitilago. Pre-treatment of Psoralens against sUV-B (pUV-B), stimulates higher production of UV-B protective pigments (flavonoids and carotenoids) and helps in maintaining its biomass against UV-B stress. Antioxidative defense system in the test plant was activated by combined treatment of Psoralens and sUV-B as evidenced by the enhanced activity of enzymatic (ascorbate peroxidase-APX, superoxide dismutase-SOD, POX) and non-enzymatic (ascorbic acid and phenol) antioxidants. Individual treatments of Psoralens and sUV-B showed inhibitory effect on various morphological traits i.e. reduction in plant height, leaf area and ultimately on biomass production. Our results clearly indicated that adverse effect of sUV-B on biomass production was ameliorated by pre- treatment with Psoralens.

Can arbuscular mycorrhizal fungi reduce Cd uptake and alleviate Cd toxicity of Lonicera japonica grown in Cd-added soils?

Science.gov (United States)

Jiang, Qiu-Yun; Zhuo, Feng; Long, Shi-Hui; Zhao, Hai-Di; Yang, Dan-Jing; Ye, Zhi-Hong; Li, Shao-Shan; Jing, Yuan-Xiao

2016-02-01

A greenhouse pot experiment was conducted to study the impact of arbuscular mycorrhizal fungi-Glomus versiforme (Gv) and Rhizophagus intraradices (Ri) on the growth, Cd uptake, antioxidant indices [glutathione reductase (GR), ascorbate peroxidase (APX), superoxide dismutase (SOD), catalase (CAT), ascorbate (ASA), glutathione (GSH) and malonaldehyde (MDA)] and phytochelatins (PCs) production of Lonicera japonica in Cd-amended soils. Gv and Ri significantly increased P acquisition, biomass of shoots and roots at all Cd treatments. Gv significantly decreased Cd concentrations in shoots and roots, and Ri also obviously reduced Cd concentrations in shoots but increased Cd concentrations in roots. Meanwhile, activities of CAT, APX and GR, and contents of ASA and PCs were remarkably higher in Gv/Ri-inoculated plants than those of uninoculated plants, but lower MDA and GSH contents in Gv/Ri-inoculated plants were found. In conclusion, Gv and Ri symbiosis alleviated Cd toxicity of L. japonica through the decline of shoot Cd concentrations and the improvement of P nutrition, PCs content and activities of GR, CAT, APX in inoculated plants, and then improved plant growth. The decrease of shoot Cd concentrations in L. japonica inoculated with Gv/Ri would provide a clue for safe production of this plant from Cd-contaminated soils.

Protection of E. coli against radiation lethality by ascorbate combined with tetracycline

Energy Technology Data Exchange (ETDEWEB)

Djalali-Behzad, G; Ehrenberg, L [Stockholm Univ. (Sweden). Radiobiologiska Institutionen

1977-06-01

The radioprotective action in E.coli ATCC 9637 of ascorbate added to media containing the weak sensitizer, tetracycline (Pittillo, R.F., and Lucas, M.B., 1967, Radiat. Res., vol. 31, 36) was found to be dependent on the presence of metal catalysts of the autoxidation of ascorbate. Thus, the protective action of ascorbate + tetracycline as well as the rate of autoxidation of ascorbate in this mixture were enhanced by 0.1 ..mu..M Cu, and these effects were counteracted by pyrophosphate probably through chelation of iron that contaminates phosphate. A suppression of metabolism is apparently involved in the combined action as judged by the decrease of incorporation of labelled uridine.

Effect of salinity on Brassica rapa var. toria (BRSRT under selenium defence: A trial to assess the protective role of selenium

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Akanksha SAO

2017-12-01

Full Text Available The present study assesses the role of selenium, an antioxidant in salt-stressed plants. A hydroponic trial of sodium selenate (Na2SeO4 on the growth, oxidative stress and antioxidant protection system of Brassica rapa var. toria (BRSRT plant was studied. 40 µmol and 100 µmol of Na2SeO4 were hydroponically applied to BRSRT roots with 50 mmol and 100 mmol sodium chloride (NaCl for 12 days. Plant growth, biomass production and photosynthetic pigments at 100 mmol salt stress was inhibited while oxidative stress indicators, for example, hydrogen peroxide and lipid peroxidation were stimulated. Supplementation of 40 µmol Na2SeO4 with 50 mmol and 100 mmol NaCl improved growth, photosynthetic pigments and acted as an antioxidant by inhibiting lipid peroxidation and increasing superoxide dismutase, ascorbate peroxidase, catalase, glutathione peroxidase, glutathione reductase activities. The in-gel assays also showed enhanced activities of these enzymes. At 100 µmol concentration, selenium under salt stress, repressed growth and expression of antioxidant enzymes and stimulated oxidative stress with enhanced glutathione peroxidase activity. Under consolidated stress treatment, an addition of 40 µmol Na2SeO4 was the most effective for both NaCl concentrations. The finding reveals that the optimal selenium supplementation presents a promising potential for use in conditions of relatively high levels of NaCl stress for BRSRT seedlings.

Chemical dosimetry by UV spectrophotometry of aqueous ascorbic acid solutions

International Nuclear Information System (INIS)

Alian, A.; El-Assay, N.B.; Abdel-Rehim, F.; Amin, N.E.; McLaughlin, W.L.; Roushdy, H.

1984-01-01

The decrease in the ultraviolet absorption of aqueous solutions of ascorbic acid brought about by large doses of gamma radiation has been investigated as a means of developing a new chemical dosimeter. Because of spontaneous ring opening under various conditions after dissolution in water, some additives were examined as possible stabilizers against such denaturing of aqueous ascorbic acid. At an ascorbic acid concentration of 10 -4 M, either 1 to 2% glycine or 0.2 M NaCl was found to be a good stabilizer. A mechanism of radiation chemistry has been proposed based on hydroxyl radical and hydroxyl adduct intermediates, leading to dehydroascorbic acid through the ascorbate complex. The optimum dosimeter solution covers an absorbed dose range approx. 50 to 350 Gy, when measured at 264 nm wavelength. The G-values for dehydroascorbic acid production were determined to be 2.94 +- 0.33 and 2.43 +- 0.11 (100 eV) -1 , with glycine and NaCl used respectively as stabilizers. (author)

Expression, purification and characterization of a peroxidase from ...

African Journals Online (AJOL)

Peroxidase is one of the key enzymes of the cellular antioxidant defense system, which is mostly involved in the reduction of hydrogen peroxide. Here, a peroxidase gene, named ThPOD1 was isolated from a cDNA library, which was generated from root tissue of Tamarix hispida that was exposed to 0.4 M NaCl. The cDNA ...

Optimization of lignin peroxidase, manganese peroxidase, and Lac production from Ganoderma lucidum under solid state fermentation of pineapple leaf

OpenAIRE

Sudha Hariharan; Padma Nambisan

2013-01-01

This study was undertaken to isolate ligninase-producing white-rot fungi for use in the extraction of fibre from pineapple leaf agriwaste. Fifteen fungal strains were isolated from dead tree trunks and leaf litter. Ligninolytic enzymes (lignin peroxidase (LiP), manganese peroxidase (MnP), and laccase (Lac)), were produced by solid-state fermentation (SSF) using pineapple leaves as the substrate. Of the isolated strains, the one showing maximum production of ligninolytic enzymes was identified...

A novel turn-on fluorescent strategy for sensing ascorbic acid using graphene quantum dots as fluorescent probe.

Science.gov (United States)

Liu, Hua; Na, Weidan; Liu, Ziping; Chen, Xueqian; Su, Xingguang

2017-06-15

In this paper, a facile and rapid fluorescence turn-on assay for fluorescent detection of ascorbic acid (AA) was developed by using the orange emission graphene quantum dots (GQDs). In the presence of horse radish peroxidase (HRP) and hydrogen peroxide (H 2 O 2 ), catechol can be oxidized by hydroxyl radicals and converted to o-benzoquinone, which can significantly quench the fluorescence of GQDs. However, when AA present in the system, it can consume part of H 2 O 2 and hydroxyl radicals to inhibit the generation of o-benzoquinone, resulting in fluorescence recovery. Under the optimized experimental conditions, the fluorescence intensity was linearly correlated with the concentration of H 2 O 2 in the range of 3.33-500µM with a detection limit of 1.2µM. The linear detection for AA was in the range from 1.11 to 300µM with a detection limit of 0.32µM. The proposed method was applied to the determination of AA in human serum samples with satisfactory results. Copyright © 2017. Published by Elsevier B.V.

Salivary ascorbic acid levels in betel quid chewers: A biochemical study

OpenAIRE

Shetty, Shishir R.; Babu, Subhas; Kumari, Suchetha; Prasad, Rajendra; Bhat, Supriya; Fazil, K. A.

2013-01-01

Background: Quid chewing practice has been a part of our tradition since centuries with little known evidence of oral cancer. However, recent trends show a rise in occurrence of oral cancer often associated with tobacco and arecanut usage. Ascorbic acid is an important salivary antioxidant. Betel leaf which is used in quid is known to contain ascorbic acid. Aim: The aim of our study was to assess the salivary levels of ascorbic acid in traditional quid chewers so as to determine whether the b...

Ascorbate status modulates reticuloendothelial iron stores and response to deferasirox iron chelation in ascorbate-deficient rats

DEFF Research Database (Denmark)

Brewer, Casey; Otto-Duessel, Maya; Lykkesfeldt, Jens

2012-01-01

Iron chelation is essential to patients on chronic blood transfusions to prevent toxicity from iron overload and remove excess iron. Deferasirox (DFX) is the most commonly used iron chelator in the United States; however, some patients are relatively refractory to DFX therapy. We postulated...... that vitamin C supplementation would improve the availability of transfusional iron to DFX treatment by promoting iron's redox cycling, increasing its soluble ferrous form and promoting its release from reticuloendothelial cells. Osteogenic dystrophy rats (n = 54) were given iron dextran injections for 10...... 12 weeks of sham chelation. Most importantly, ascorbate supplementation at 2250 ppm improved DFX efficiency, allowing DFX to remove 21% more hepatic iron than ascorbate supplementation with 900 ppm or 150 ppm (p vitamin C status modulates the release of iron from...

Role of ascorbic acid in stratum corneum lipid models exposed to UV irradiation.

Science.gov (United States)

Trommer, Hagen; Böttcher, Roif; Pöppl, Andreas; Hoentsch, Joachim; Wartewig, Siegfried; Neubert, Reinhard H H

2002-07-01

The effects of ascorbic acid on Stratum corneum lipid models following ultraviolet irradiation were studied adding iron ions as transition metal catalysts. Lipid peroxidation was quantified by the thiobarbituric acid assay. The qualitative changes were studied on a molecular level by mass spectrometry. To elucidate the nature of free radical involvement we carried out electron paramagnetic resonance studies. The influence of ascorbic acid on the concentration of hydroxyl radicals was examined using the spin trapping technique. Moreover, we checked the vitamin's ability to react with stable radicals. Ascorbic acid was found to have prooxidative effects in all lipid systems in a concentration dependent manner. The degradation products of ascorbic acid after its prooxidative action were detected. The concentration of the hydroxyl radicals in the Fenton assay was decreased by ascorbic acid. The quantification assay of 2,2-diphenyl-1-picrylhydrazyl hydrate showed reduced concentration levels of the stable radical caused by ascorbic acid. Considering human skin and its constant exposure to UV light and oxygen, an increased pool of iron ions in irradiated skin and the depletion of co-antioxidants, the administration of ascorbic acid in cosmetic formulations or in sunscreens could unfold adverse effects among the Stratum corneum lipids.

A metabolic switch in brain: glucose and lactate metabolism modulation by ascorbic acid.

Science.gov (United States)

Castro, Maite A; Beltrán, Felipe A; Brauchi, Sebastián; Concha, Ilona I

2009-07-01

In this review, we discuss a novel function of ascorbic acid in brain energetics. It has been proposed that during glutamatergic synaptic activity neurons preferably consume lactate released from glia. The key to this energetic coupling is the metabolic activation that occurs in astrocytes by glutamate and an increase in extracellular [K(+)]. Neurons are cells well equipped to consume glucose because they express glucose transporters and glycolytic and tricarboxylic acid cycle enzymes. Moreover, neuronal cells express monocarboxylate transporters and lactate dehydrogenase isoenzyme 1, which is inhibited by pyruvate. As glycolysis produces an increase in pyruvate concentration and a decrease in NAD(+)/NADH, lactate and glucose consumption are not viable at the same time. In this context, we discuss ascorbic acid participation as a metabolic switch modulating neuronal metabolism between rest and activation periods. Ascorbic acid is highly concentrated in CNS. Glutamate stimulates ascorbic acid release from astrocytes. Ascorbic acid entry into neurons and within the cell can inhibit glucose consumption and stimulate lactate transport. For this switch to occur, an ascorbic acid flow is necessary between astrocytes and neurons, which is driven by neural activity and is part of vitamin C recycling. Here, we review the role of glucose and lactate as metabolic substrates and the modulation of neuronal metabolism by ascorbic acid.

Peroxidase gene discovery from the horseradish transcriptome.

Science.gov (United States)

Näätsaari, Laura; Krainer, Florian W; Schubert, Michael; Glieder, Anton; Thallinger, Gerhard G

2014-03-24

Horseradish peroxidases (HRPs) from Armoracia rusticana have long been utilized as reporters in various diagnostic assays and histochemical stainings. Regardless of their increasing importance in the field of life sciences and suggested uses in medical applications, chemical synthesis and other industrial applications, the HRP isoenzymes, their substrate specificities and enzymatic properties are poorly characterized. Due to lacking sequence information of natural isoenzymes and the low levels of HRP expression in heterologous hosts, commercially available HRP is still extracted as a mixture of isoenzymes from the roots of A. rusticana. In this study, a normalized, size-selected A. rusticana transcriptome library was sequenced using 454 Titanium technology. The resulting reads were assembled into 14871 isotigs with an average length of 1133 bp. Sequence databases, ORF finding and ORF characterization were utilized to identify peroxidase genes from the 14871 isotigs generated by de novo assembly. The sequences were manually reviewed and verified with Sanger sequencing of PCR amplified genomic fragments, resulting in the discovery of 28 secretory peroxidases, 23 of them previously unknown. A total of 22 isoenzymes including allelic variants were successfully expressed in Pichia pastoris and showed peroxidase activity with at least one of the substrates tested, thus enabling their development into commercial pure isoenzymes. This study demonstrates that transcriptome sequencing combined with sequence motif search is a powerful concept for the discovery and quick supply of new enzymes and isoenzymes from any plant or other eukaryotic organisms. Identification and manual verification of the sequences of 28 HRP isoenzymes do not only contribute a set of peroxidases for industrial, biological and biomedical applications, but also provide valuable information on the reliability of the approach in identifying and characterizing a large group of isoenzymes.

Lipid peroxidation and ascorbic acid levels in Nigeria children with ...

African Journals Online (AJOL)

This study was undertaken to establish data on the roles of lipid peroxidation and ascorbic acid in the pathology of malaria in Nigeria children. We measured the levels of malondialdehyde (MDA), a marker of lipid peroxidation and ascorbic acid in the plasma of 406 parasitaemic and 212 non-parasitaemic Nigerian children.

Effect of Ascorbic Acid on Noise Induced Hearing Loss in Rats

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Ziba Loukzadeh

2015-07-01

Full Text Available Introduction: After presbycusis, noise-induced hearing loss is the second most common cause of acquired hearing loss. Numerous studies have shown that high-intensity noise exposure increases free radical species; therefore, use of antioxidants to detoxify the free radicals can prevent cellular damage in the cochlea. We studied the potential hearing protective effect of different doses of ascorbic acid administered prior to noise exposure in rats.   Materials and Methods: Twenty-four male albino Wistar rats were randomly allocated into four groups: groups A, B, and C received 1250, 250, and 50 mg/kg/day of ascorbic acid, respectively, and group D acted as the control group. After 14 days of ascorbic acid administration, the rats were exposed to noise (105 dB sound pressure level for 2 h. Distortion product otoacoustic emissions (DPOAE were recorded prior to starting the ascorbic acid as baseline and 1 h after the noise exposure.   Results: The amplitude decrease was 14.99 dB for group A, 16.11 dB for group B, 28.82 dB for group C, and 29.91 dB for the control group. Moderate and high doses of ascorbic acid significantly reduced the transient threshold shift in the rats.   Conclusion:  The results of present study support the concept of cochlea protection by antioxidant agents. This dose-dependent protective effect was shown through the use of ascorbic acid treatment prior to noise exposure.

Aortic wall damage in mice unable to synthesize ascorbic acid.

Science.gov (United States)

Maeda, N; Hagihara, H; Nakata, Y; Hiller, S; Wilder, J; Reddick, R

2000-01-18

By inactivating the gene for L-gulono-gamma-lactone oxidase, a key enzyme in ascorbic acid synthesis, we have generated mice that, like humans, depend on dietary vitamin C. Regular chow, containing about 110 mg/kg of vitamin C, is unable to support the growth of the mutant mice, which require L-ascorbic acid supplemented in their drinking water (330 mg/liter). Upon withdrawal of supplementation, plasma and tissue ascorbic acid levels decreased to 10-15% of normal within 2 weeks, and after 5 weeks the mutants became anemic, began to lose weight, and die. Plasma total antioxidative capacities were approximately 37% normal in homozygotes after feeding the unsupplemented diet for 3-5 weeks. As plasma ascorbic acid decreased, small, but significant, increases in total cholesterol and decreases in high density lipoprotein cholesterol were observed. The most striking effects of the marginal dietary vitamin C were alterations in the wall of aorta, evidenced by the disruption of elastic laminae, smooth muscle cell proliferation, and focal endothelial desquamation of the luminal surface. Thus, marginal vitamin C deficiency affects the vascular integrity of mice unable to synthesize ascorbic acid, with potentially profound effects on the pathogenesis of vascular diseases. Breeding the vitamin C-dependent mice with mice carrying defined genetic mutations will provide numerous opportunities for systematic studies of the role of antioxidants in health and disease.

Sulfur dioxide alleviates programmed cell death in barley aleurone by acting as an antioxidant.

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Sha-Sha Wang

Full Text Available Sulfur dioxide (SO2, a gaseous signaling molecule in animal cells, has recently been found to play a physiological role in plants. Here we studied the role of SO2 in gibberellic acid (GA3-induced programmed cell death (PCD in barley (Hordeum vulgare L. aleurone layers. The application of the SO2 donor (NaHSO3/Na2SO3, 1:3 M/M effectively alleviated PCD in barley aleurone layers in a dose-dependent manner with an optimal concentration of 50 μM. Further investigations showed that SO2 reduced the accumulation of hydrogen peroxide (H2O2, superoxide anion (⋅O2- and malondialdehyde (MDA in aleurone layers. Moreover, the activities of antioxidant enzymes such as superoxide dismutase (SOD, catalase (CAT, ascorbate peroxidase (APX, glutathione reductase (GR and guaiacol peroxidase (POD were enhanced by SO2 donor treatment. Meanwhile, lipoxygenase (LOX activity was attenuated by SO2 donor treatment. Furthermore, an induction of endogenous H2S and NO were also observed in SO2-treated aleurone layers, suggesting interactions of SO2 with other well-known signaling molecules. Taken together, we show that SO2 negatively regulated PCD by acting as an antioxidant to scavenge excessive reactive oxygen species (ROS generated during PCD.

Effects of benzoic acid and cadmium toxicity on wheat seedlings

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Kavita Yadav

2013-06-01

Full Text Available Benzoic acid (BA and Cd exhibit cumulative effects on plants due to their accumulation in the soil. The present study reports the effects of BA an allelochemical, Cd and their combinations on seed germination, seedling growth, biochemical parameters, and response of antioxidant enzymes in Triticum aestivum L. The experiment was conducted in sand supplemented with Hoagland nutrient solution. Benzoic acid was applied at concentrations of 0.5, 1.0, and 1.5 mM with or without Cd (7 mg L-1 to observe effects of allelochemical and Cd alone and in combination on wheat. Both stresses exhibited inhibitory effect on growth and metabolism of wheat seedlings. The allelochemical in single and combined treatments with Cd decreased seedling growth as compared to Cd stress. The two stresses significantly enhanced malondialdehyde content of wheat seedlings. The activity of other antioxidant enzymes, viz. superoxide dismutase (SOD, catalase (CAT, ascorbate peroxidase (APX, and guaiacol peroxidase (POX were also recorded. SOD increased in seedlings under the two stresses. CAT more prominently ameliorates the toxic effects of H2O2 as compared with APX and POX and protected wheat seedlings from oxidative stress. Allelochemical buttressed the toxic effect of Cd on wheat seedlings.

Effects of sodium nitroprusside (SNP) pretreatment on UV-B stress tolerance in lettuce (Lactuca sativa L.) seedlings.

Science.gov (United States)

Esringu, Aslıhan; Aksakal, Ozkan; Tabay, Dilruba; Kara, Ayse Aydan

2016-01-01

Ultraviolet-B (UV-B) radiation is one of the most important abiotic stress factors that could influence plant growth, development, and productivity. Nitric oxide (NO) is an important plant growth regulator involved in a wide variety of physiological processes. In the present study, the possibility of enhancing UV-B stress tolerance of lettuce seedlings by the exogenous application of sodium nitroprusside (SNP) was investigated. UV-B radiation increased the activities of superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), peroxidase (POD) and total phenolic concentrations, antioxidant capacity, and expression of phenylalanine ammonia lyase (PAL) gene in seedlings, but the combination of SNP pretreatment and UV-B enhanced antioxidant enzyme activities, total phenolic concentrations, antioxidant capacity, and PAL gene expression even more. Moreover, UV-B radiation significantly inhibited chlorophylls, carotenoid, gibberellic acid (GA), and indole-3-acetic acid (IAA) contents and increased the contents of abscisic acid (ABA), salicylic acid (SA), malondialdehyde (MDA), hydrogen peroxide (H2O2), and superoxide radical (O2•(-)) in lettuce seedlings. When SNP pretreatment was combined with the UV-B radiation, we observed alleviated chlorophylls, carotenoid, GA, and IAA inhibition and decreased content of ABA, SA, MDA, H2O2, and O2•(-) in comparison to non-pretreated stressed seedlings.

Nitric oxide induced by polyamines involves antioxidant systems against chilling stress in tomato (Lycopersicon esculentum Mill.) seedling*#

Science.gov (United States)

Diao, Qian-Nan; Song, Yong-Jun; Shi, Dong-Mei; Qi, Hong-Yan

2016-01-01

Polyamines (PAs) and nitric oxide (NO) are vital signals in modulating plant response to abiotic stress. However, to our knowledge, studies on the relationship between NO and PAs in response to cold stress in tomato are limited. Accordingly, in this study, we investigated the effects of putrescine (Put) and spermidine (Spd) on NO generation and the function of Spd-induced NO in the tolerance of tomato seedling under chilling stress. Spd increased NO release via the nitric oxide synthase (NOS)-like and nitrate reductase (NR) enzymatic pathways in the seedlings, whereas Put had no such effect. Moreover, H2O2 might act as an upstream signal to stimulate NO production. Both exogenous NO donor (sodium nitroprusside (SNP)) and Spd enhanced chilling tolerance in tomato, thereby protecting the photosynthetic system from damage. Compared to chilling treatment alone, Spd enhanced the gene expressions of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and ascorbate peroxidase (APX), and their enzyme activities in tomato leaves. However, a scavenger or inhibitor of NO abolished Spd-induced chilling tolerance and blocked the increased expression and activity due to Spd of these antioxidant enzymes in tomato leaves under chilling stress. The results showed that NO induced by Spd plays a crucial role in tomato’s response to chilling stress. PMID:27921397

Nitric oxide induced by polyamines involves antioxidant systems against chilling stress in tomato (Lycopersicon esculentum Mill.) seedling.

Science.gov (United States)

Diao, Qian-Nan; Song, Yong-Jun; Shi, Dong-Mei; Qi, Hong-Yan

Polyamines (PAs) and nitric oxide (NO) are vital signals in modulating plant response to abiotic stress. However, to our knowledge, studies on the relationship between NO and PAs in response to cold stress in tomato are limited. Accordingly, in this study, we investigated the effects of putrescine (Put) and spermidine (Spd) on NO generation and the function of Spd-induced NO in the tolerance of tomato seedling under chilling stress. Spd increased NO release via the nitric oxide synthase (NOS)-like and nitrate reductase (NR) enzymatic pathways in the seedlings, whereas Put had no such effect. Moreover, H 2 O 2 might act as an upstream signal to stimulate NO production. Both exogenous NO donor (sodium nitroprusside (SNP)) and Spd enhanced chilling tolerance in tomato, thereby protecting the photosynthetic system from damage. Compared to chilling treatment alone, Spd enhanced the gene expressions of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and ascorbate peroxidase (APX), and their enzyme activities in tomato leaves. However, a scavenger or inhibitor of NO abolished Spd-induced chilling tolerance and blocked the increased expression and activity due to Spd of these antioxidant enzymes in tomato leaves under chilling stress. The results showed that NO induced by Spd plays a crucial role in tomato's response to chilling stress.

Exogenous Melatonin Confers Cadmium Tolerance by Counterbalancing the Hydrogen Peroxide Homeostasis in Wheat Seedlings

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Jun Ni

2018-03-01

Full Text Available Melatonin has emerged as a research highlight regarding its important role in regulating plant growth and the adaptation to the environmental stresses. In this study, we investigated how melatonin prevented the cadmium toxicity to wheat seedlings. The results demonstrated that cadmium induced the expression of melatonin biosynthesis-related genes and cause a significant increase of endogenous melatonin level. Melatonin treatment drastically alleviated the cadmium toxicity, resulting in increased plant height, biomass accumulation, and root growth. Cadmium and senescence treatment significantly increased the endogenous level of hydrogen peroxide, which was strictly counterbalanced by melatonin. Furthermore, melatonin treatment caused a significant increase of GSH (reduced glutathione content and the GSH/GSSG (oxidized glutathione ratio. The activities of two key antioxidant enzymes, ascorbate peroxidase (APX and superoxide dismutase (SOD, but not catalase (CAT and peroxidase (POD, were specifically improved by melatonin. Additionally, melatonin not only promoted the primary root growth, but also drastically enhanced the capacity of the seedling roots to degrade the exogenous hydrogen peroxide. These results suggested that melatonin played a key role in maintaining the hydrogen peroxide homeostasis, via regulation of the antioxidant systems. Conclusively, this study revealed a crucial protective role of melatonin in the regulation of cadmium resistance in wheat.

Exogenous Melatonin Confers Cadmium Tolerance by Counterbalancing the Hydrogen Peroxide Homeostasis in Wheat Seedlings.

Science.gov (United States)

Ni, Jun; Wang, Qiaojian; Shah, Faheem Afzal; Liu, Wenbo; Wang, Dongdong; Huang, Shengwei; Fu, Songling; Wu, Lifang

2018-03-30

Melatonin has emerged as a research highlight regarding its important role in regulating plant growth and the adaptation to the environmental stresses. In this study, we investigated how melatonin prevented the cadmium toxicity to wheat seedlings. The results demonstrated that cadmium induced the expression of melatonin biosynthesis-related genes and cause a significant increase of endogenous melatonin level. Melatonin treatment drastically alleviated the cadmium toxicity, resulting in increased plant height, biomass accumulation, and root growth. Cadmium and senescence treatment significantly increased the endogenous level of hydrogen peroxide, which was strictly counterbalanced by melatonin. Furthermore, melatonin treatment caused a significant increase of GSH (reduced glutathione) content and the GSH/GSSG (oxidized glutathione) ratio. The activities of two key antioxidant enzymes, ascorbate peroxidase (APX) and superoxide dismutase (SOD), but not catalase (CAT) and peroxidase (POD), were specifically improved by melatonin. Additionally, melatonin not only promoted the primary root growth, but also drastically enhanced the capacity of the seedling roots to degrade the exogenous hydrogen peroxide. These results suggested that melatonin played a key role in maintaining the hydrogen peroxide homeostasis, via regulation of the antioxidant systems. Conclusively, this study revealed a crucial protective role of melatonin in the regulation of cadmium resistance in wheat.

Nano-silicon dioxide mitigates the adverse effects of salt stress on Cucurbita pepo L.

Science.gov (United States)

Siddiqui, Manzer H; Al-Whaibi, Mohamed H; Faisal, Mohammad; Al Sahli, Abdulaziz A

2014-11-01

Research into nanotechnology, an emerging science, has advanced in almost all fields of technology. The aim of the present study was to evaluate the role of nano-silicon dioxide (nano-SiO2 ) in plant resistance to salt stress through improvement of the antioxidant system of squash (Cucurbita pepo L. cv. white bush marrow). Seeds treated with NaCl showed reduced germination percentage, vigor, length, and fresh and dry weights of the roots and shoots. However, nano-SiO2 improved seed germination and growth characteristics by reducing malondialdehyde and hydrogen peroxide levels as well as electrolyte leakage. In addition, application of nano-SiO2 reduced chlorophyll degradation and enhanced the net photosynthetic rate (Pn ), stomatal conductance (gs ), transpiration rate, and water use efficiency. The increase in plant germination and growth characteristics through application of nano-SiO2 might reflect a reduction in oxidative damage as a result of the expression of antioxidant enzymes, such as catalase, peroxidase, superoxide dismutase, glutathione reductase, and ascorbate peroxidase. These results indicate that nano-SiO2 may improve defense mechanisms of plants against salt stress toxicity by augmenting the Pn , gs , transpiration rate, water use efficiency, total chlorophyll, proline, and carbonic anhydrase activity in the leaves of plants. © 2014 SETAC.

Phytoremediation of arsenic-contaminated water: the role of antioxidant metabolism of Azolla caroliniana Willd. (Salviniales

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Gabriela Alves Leão

Full Text Available ABSTRACT Phytoremediation has proven to be an efficient technology for removing arsenic (As from water, but the plants used in this process need to be tolerant to the damage caused by As. The toxic effect of As on growth and functioning of the antioxidant system was studied in individual plants of Azolla caroliniana exposed to five concentrations of As (0.0, 0.25, 0.5, 1.0 and 1.5 mg L-1 for the course of five days. Growth, As absorption, enzymatic activity, total and non-protein thiols and anthocyanin content were assessed. Azolla caroliniana was able to take up large amounts of the pollutant, reaching As concentrations of 386.1 µg g-1 dry weight without saturating the absorption mechanism. The tolerance index and the growth of A. caroliniana decreased with the increased As uptake. Superoxide dismutase, peroxidases, catalases and glutathione reductase activities increased at lower doses of As and subsequently declined with higher concentrations, whereas ascorbate peroxidase activity was reduced in all treatments. Unlike the enzymatic defence system, anthocyanin and thiol content increased consistently in all treatments and showed a positive correlation with As concentration. Therefore, the increased synthesis of non-enzymatic antioxidants is most likely the main factor responsible for the high As tolerance of A. caroliniana.

Responses of Phospholipase D and Antioxidant System to Mechanical Wounding in Postharvest Banana Fruits

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Li Li

2017-01-01

Full Text Available Banana fruits are susceptible to mechanical damage. The present study was to investigate the responses of phospholipase D (PLD and antioxidant system to mechanical wounding in postharvest banana fruits. During 16 d storage at 25°C and 90% relative humidity, PLD activity in wounded fruits was significantly higher than that in control (without artificial wounding fruits. The higher value of PLD mRNA was found in wounded fruits than in control. PLD mRNA expression reached the highest peak on day 4 in both groups, but it was 2.67 times in wounded fruits compared to control at that time, indicating that PLD gene expression was activated in response to wounding stress. In response to wounding stress, the higher lipoxygenase (LOX activity was observed and malondialdehyde (MDA production was accelerated. The activities of antioxidant enzymes such as superoxide dismutase (SOD, catalase (CAT, peroxidase (POD, and ascorbate peroxidase (APX in wounded fruits were significantly higher than those in control. The concentrations of reactive oxygen species (ROS such as superoxide anion (O2•- and hydrogen peroxide (H2O2 in fruits increased under mechanical wounding. The above results provided a basis for further investigating the mechanism of postharvest banana fruits adapting to environmental stress.

Antioxidant and carbohydrate changes of two pomegranate cultivars under deficit irrigation stress

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Morteza Ebtedaie

2016-12-01

Full Text Available The purpose of this study was to evaluate the biochemical responses to water stress tolerance of two pomegranate cultivars, ‘Rabbab’ and ‘Shishehgap’. After the establishment of rooted stem cuttings of both cultivars under greenhouse conditions, they were treated with four levels of deficit irrigations (100%, 75%, 50% and 25% of field capacity in a completely randomized design with four replications. The results showed a significant difference between the two cultivars regarding antioxidant enzymes activities. In both cultivars, the water stress increased the activity of superoxide dismutase, catalase and ascorbate peroxidase. However, at high water deficit (25% field capacity, FC, ‘Rabbab’ showed significantly higher enzyme activity than ‘Shishehgap’. In each level of irrigation, there were not considerable differences in peroxidase activity between the two cultivars. An increment of 162% and 65.5% in soluble sugar was gained at 50% FC in ‘Rabbab’ and ‘Shishehgap’, respectively. ‘Rabbab’ showed better growth performance in each level of irrigation than ‘Shishehgap’. Therefore, it can be concluded that 'Rabbab', with lesser decline in leaf relative water content (RWC, a strong antioxidant system and accumulation of more soluble carbohydrates, can resist higher water stress than 'Shishehgap'.

To Analyze the Amelioration of Phenobarbital Induced Oxidative Stress by Erucin, as Indicated by Biochemical and Histological Alterations.

Science.gov (United States)

Arora, Rohit; Bhushan, Sakshi; Kumar, Rakesh; Mannan, Rahul; Kaur, Pardeep; Singh, Bikram; Sharma, Ritika; Vig, Adarsh Pal; Singh, Balbir; Singh, Amrit Pal; Arora, Saroj

2016-01-01

Phenobarbital is a commonly employed antidepressant and anti-epileptic drug. The cancer promoting activity of this genotoxic xenobiotic is often ignored. It is responsible for oxidative stress leading to modulation in xenobiotic and antioxidative enzymes. Glucosinolates and more specifically their hydrolytic products are known for their antioxidative and anticancer activities. The present study involves the analysis of hepatoprotective effect of erucin (isolated from Eruca sativa (Mill.) Thell.) against phenobarbital mediated hepatic damage in male wistar rats. The liver homogenate was analyzed for oxidative stress (superoxide dismutase, catalase, guaiacol peroxidase, ascorbate peroxidase, glutathione reductase and lactate dehydrogenase), other oxidative parameters (thiobarbituric acid reactive species, conjugated dienes and lipid hydroperoxide), phase I enzymes (NADPH-cytochrome P450 reductase, NADH-cytochrome b5 reductase, cytochrome P420, cytochrome P450 and cytochrome b5), phase II enzymes (γ-glutamyl transpeptidase, DT-diaphorase and glutathione-S-transferase), serum parameters (alkaline phosphatase, serum glutamic oxaloacetic transaminase, serum glutamic pyruvic transaminase, direct bilirubin and total bilirubin) and certain histological parameters. Erucin accorded protection from phenobarbital induced hepatic damage by normalizing antioxidative enzymes, other oxidative parameters, phase I, II, and serum parameters. Erucin, an analogue of sulforaphane has the potential to act as an anticancer agent by regulating various biochemical parameters.

Toxic reactivity of wheat (Triticum aestivum) plants to herbicide isoproturon.

Science.gov (United States)

Yin, Xiao Le; Jiang, Lei; Song, Ning Hui; Yang, Hong

2008-06-25

The herbicide isoproturon is widely used for controlling weed/grass in agricultural practice. However, the side effect of isoproturon as contaminants on crops is unknown. In this study, we investigated isoproturon-induced oxidative stress in wheat ( Triticum aestivum). The plants were grown in soils with isoproturon at 0-20 mg/kg and showed negative biological responses. The growth of wheat seedlings with isoproturon was inhibited. Chlorophyll content significantly decreased at the low concentration of isoproturon (2 mg/kg), suggesting that chlorophyll was rather sensitive to isoproturon exposure. The level of thiobarbituric acid reactive substances (TBARS), an indicator of cellular peroxidation, showed an increase, indicating oxidative damage to plants. The isoproturon-induced oxidative stress resulted in a substantial change in activities of the majority of antioxidant enzymes, including superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and ascorbate peroxidase (APX). Activities of the antioxidant enzymes showed a general increase at low isoproturon concentrations and a decrease at high isoproturon concentrations. Activities of CAT in leaves showed progressive suppression under the isoproturon exposure. Analysis of nondenaturing polyacrylamide gel electrophoresis (PAGE) confirmed these results. We also tested the activity of glutathione S-transferase (GST) and observed the activity stimulated by isoproturon at 2-10 mg/kg.

Antioxidant and carbohydrate changes of two pomegranate cultivars under deficit irrigation stress

Energy Technology Data Exchange (ETDEWEB)

Ebtedaie, M.; Shekafandeh, A.

2016-07-01

The purpose of this study was to evaluate the biochemical responses to water stress tolerance of two pomegranate cultivars, ‘Rabbab’ and ‘Shishehgap’. After the establishment of rooted stem cuttings of both cultivars under greenhouse conditions, they were treated with four levels of deficit irrigations (100%, 75%, 50% and 25% of field capacity) in a completely randomized design with four replications. The results showed a significant difference between the two cultivars regarding antioxidant enzymes activities. In both cultivars, the water stress increased the activity of superoxide dismutase, catalase and ascorbate peroxidase. However, at high water deficit (25% field capacity, FC), ‘Rabbab’ showed significantly higher enzyme activity than ‘Shishehgap’. In each level of irrigation, there were not considerable differences in peroxidase activity between the two cultivars. An increment of 162% and 65.5% in soluble sugar was gained at 50% FC in ‘Rabbab’ and ‘Shishehgap’, respectively. ‘Rabbab’ showed better growth performance in each level of irrigation than ‘Shishehgap’. Therefore, it can be concluded that 'Rabbab', with lesser decline in leaf relative water content (RWC), a strong antioxidant system and accumulation of more soluble carbohydrates, can resist higher water stress than 'Shishehgap'.

The activity of catalase and superoxide dismutase in isogenous bacteria strains with different radioresistance

International Nuclear Information System (INIS)

Vasil'eva, E.I.; Goncharenko, E.N.; Yudz, T.I.; Samojlenko, I.I.

1984-01-01

The catalase and superoxide dismutase activity in isogenous bacterial strains with various radiosensitivity is investigated. In micrococcus radiodurans mutants with defects in the DNA repair systems the superoxide dismutase activity is lower than in the wild type cells. In investigated Escherichia coli strains differing in radiosensitivity, no alteration in catalase and superoxide dismutase activity is found. The conclusion is drawn that viability of bacteria subjected to the effect of ionizing radiations is determined by the efficiency of DNA repair systems whose functional reliability is sometimes connected with the catalase and suferoxide dismutase activity

Oral administration of L-arginine in patients with angina or following myocardial infarction may be protective by increasing plasma superoxide dismutase and total thiols with reduction in serum cholesterol and xanthine oxidase

Science.gov (United States)

Tripathi, Pratima; Chandra, M

2009-01-01

Administration of L-arginine has been shown to control ischemic injury by producing nitric oxide which dilates the vessels and thus maintains proper blood flow to the myocardium. In the present study attempt has been made to determine whether oral administration of L-arginine has any effect on oxidant/antioxidant homeostasis in ischemic myocardial patients [represented by the patients of acute angina (AA) and acute myocardial infarction (MI)]. L-arginine has antioxidant and antiapoptotic properties, decreases endothelin-1 expression and improves endothelial function, thereby controlling oxidative injury caused during myocardial ischemic syndrome. Effect of L-arginine administration on the status of free radical scavenging enzymes, pro-oxidant enzyme and antioxidants viz. total thiols, carbonyl content and plasma ascorbic acid levels in the patients has been evaluated. We have observed that L-arginine administration (three grams per day for 15 days) resulted in increased activity of free radical scavenging enzyme superoxide dismutase (SOD) and increase in the levels of total thiols (T-SH) and ascorbic acid with concomitant decrease in lipid per-oxidation, carbonyl content, serum cholesterol and the activity of proxidant enzyme, xanthine oxidase (XO). These findings suggest that the supplementation of L-arginine along with regular therapy may be beneficial to the patients of ischemic myocardial syndromes. PMID:20716909

Oral Administration of L-Arginine in Patients With Angina or Following Myocardial Infarction May Be Protective By Increasing Plasma Superoxide Dismutase and Total Thiols With Reduction in Serum Cholesterol and Xanthine Oxidase

Directory of Open Access Journals (Sweden)

Pratima Tripathi

2009-01-01

Full Text Available Administration of L-arginine has been shown to control ischemic injury by producing nitric oxide which dilates the vessels and thus maintains proper blood flow to the myocardium. In the present study attempt has been made to determine whether oral administration of L-arginine has any effect on oxidant/antioxidant homeostasis in ischemic myocardial patients [represented by the patients of acute angina (AA and acute myocardial infarction (MI]. L-arginine has antioxidant and antiapoptotic properties, decreases endothelin-1 expression and improves endothelial function, thereby controlling oxidative injury caused during myocardial ischemic syndrome. Effect of L-arginine administration on the status of free radical scavenging enzymes, pro-oxidant enzyme and antioxidants viz. total thiols, carbonyl content and plasma ascorbic acid levels in the patients has been evaluated. We have observed that L-arginine administration (three grams per day for 15 days resulted in increased activity of free radical scavenging enzyme superoxide dismutase (SOD and increase in the levels of total thiols (T-SH and ascorbic acid with concomitant decrease in lipid per-oxidation, carbonyl content, serum cholesterol and the activity of proxidant enzyme, xanthine oxidase (XO. These findings suggest that the supplementation of L-arginine along with regular therapy may be beneficial to the patients of ischemic myocardial syndromes.

Effect of ascorbic acid supplementation level to diets of indigenous ...

African Journals Online (AJOL)

All the birds were offered the same grower feed and fresh water ad libitum. Indigenous Venda hens supplemented with ascorbic acid produced chicks with improved (P<0.05) feed intake, feed conversion ratio, growth rate and live weight at 7 weeks of age. However, ascorbic acid supplementation to the diets of indigenous ...

Endogenous superoxide dismutase and catalase activities and radiation resistance in mouse cell lines

International Nuclear Information System (INIS)

Davy, C.A.; Tesfay, Z.; Jones, J.; Rosenberg, R.C.; McCarthy, C.; Ostrand-Rosenberg, S.

1988-01-01

The relationship between the endogenous cytoplasmic levels of the enzymes superoxide dismutase and catalase and the inhibition of cell proliferation by γ-radiation has been studied in 11 mouse cell lines. The resistance of these mouse cell lines to radiation was found to vary by over 25-fold. No correlation was found between the cytoplasmic level of CuZn-superoxide dismutase or catalase and the resistance to radiation as measured by extrapolation number (EN), quasi-threshold dose (Dsub(q)), or Dsub(o). None of the cell lines had detectable cytoplasmic Mn-superoxide dismutase. The apparent Ksub(i) of potassium cyanide for mouse CuZn-superoxide dismutase was determined (Ksub(i) = 6.5 μmol dm -3 ). (author)

Transport of ascorbic acid and dehydroascorbic acid by pancreatic islet cells from neonatal rats

DEFF Research Database (Denmark)

Zhou, A; Farver, O; Thorn, N A

1991-01-01

. Dehydroascorbic acid was converted to ascorbic acid by an unknown mechanism after uptake. The uptake of both ascorbic acid and dehydroascorbic acid was inhibited by tri-iodothyronine, and uptake of ascorbic acid, but not of dehydroascorbic acid, was inhibited by glucocorticoids. Isolated secretory granules...

Ascorbate concentrations in vitro and in vivo, and their role in the radiation response of cells

International Nuclear Information System (INIS)

Stratford, M.R.L.; Hodgkiss, R.J.

1985-01-01

Hydrogen-atom or electron-transfer reactions of ascorbate are often invoked in discussing its potential role in radiobiology and free radical damage by cytotoxins, but detailed information on actual levels in experimental systems is lacking. A range of 0-250 μM ascorbate is present in several commonly used mammalian cell culture media. V79 379A Chinese hamster cells can concentrate ascorbate from medium containing 200 or 500 μM ascorbate but when ascorbate is absent in medium, cells do not appear to contain a significant amount. Tumour concentrations are approximately 1mM, similar to that of glutathione (GSH). There is much current interest in depleting cells of GSH to enhance radiosensitivity, and ascorbate is maintained by a GSH dependent enzyme, glutathione dehydrogenase. Data is presented on the effect of GSH depletion by buthionine sulphoximine on cell and tumour ascorbate levels, and the effect of ascorbate on in vitro radiosensitivity, and misonidazole sensitizing efficiency

Production of reactive oxygen species and development of antioxidative systems during in vitro growth and ex vitro transfer

Czech Academy of Sciences Publication Activity Database

Baťková, Petra; Pospíšilová, Jana; Synková, Helena

2008-01-01

Roč. 52, č. 3 (2008), s. 413-422 ISSN 0006-3134 R&D Projects: GA ČR GA522/07/0227 Institutional research plan: CEZ:AV0Z50380511 Keywords : ascorbate * ascorbate peroxidase * carotenoids Subject RIV: ED - Physiology Impact factor: 1.426, year: 2008

Production of lignin peroxidase by Ganoderma leucidum using solid ...

African Journals Online (AJOL)

The main objectives of this study were to optimize the culture conditions for the production of lignin peroxidase by Ganoderma leucidum, economic utilization of waste corn cobs as inducers substrate by pollution free fermentation technology and to optimize the solid state fermentation (SSF) process for lignin peroxidase ...

Mn(II) regulation of lignin peroxidases and manganese-dependent peroxidases from lignin-degrading white rot fungi

International Nuclear Information System (INIS)

Bonnarme, P.; Jeffries, T.W.

1990-01-01

Two families of peroxidases-lignin peroxidase (LiP) and manganese-dependent lignin peroxidase (MnP)-are formed by the lignin-degrading white rot basidiomycete Phanerochaete chrysosporium and other white rot fungi. Isoenzymes of these enzyme families carry out reactions important to the biodegradation of lignin. This research investigated the regulation of LiP and MnP production by Mn(II). In liquid culture, LiP titers varied as an inverse function of and MnP titers varied as a direct function of the Mn(II) concentration. The extracellular isoenzyme profiles differed radically at low and high Mn(II) levels, whereas other fermentation parameters, including extracellular protein concentrations, the glucose consumption rate, and the accumulation of cell dry weight, did not change significantly with the Mn(II) concentration. In the absence of Mn(II), extracellular LiP isoenzymes predominated, whereas in the presence of Mn(II), MnP isoenzymes were dominant. The release of 14 CO 2 from 14 C-labeled dehydrogenative polymerizate lignin was likewise affected by Mn(II). The rate of 14 CO 2 release increased at low Mn(II) and decreased at high Mn(II) concentrations. This regulatory effect of Mn(II) occurred with five strains of P. chrysosporium, two other species of Phanerochaete, three species of Phlebia, Lentinula edodes, and Phellinus pini

Interactive effects of herbicide and enhanced UV-B on growth, oxidative damage and the ascorbate-glutathione cycle in two Azolla species.

Science.gov (United States)

Prasad, Sheo Mohan; Kumar, Sushil; Parihar, Parul; Singh, Rachana

2016-11-01

A field experiment was conducted to investigate the impact of alone and combined exposures of herbicide pretilachlor (5, 10 and 20μgml(-1)) and enhanced UV-B radiation (UV-B1; ambient +2.2kJm(-2) day(-1) and UV-B2; ambient +4.4kJm(-2) day(-1)) on growth, oxidative stress and the ascorbate-glutathione (AsA-GSH) cycle in two agronomically important Azolla spp. viz., Azolla microphylla and Azolla pinnata. Decreased relative growth rate (RGR) in both the species under tested stress could be linked to enhanced oxidative stress, thus higher H2O2 accumulation was observed, that in turn might have caused severe damage to lipids and proteins, thereby decreasing membrane stability. The effects were exacerbated when spp. were exposed to combined treatments of enhanced UV-B and pretilachlor. Detoxification of H2O2 is regulated by enzymes/metabolites of AsA-GSH cycle such as ascorbate peroxidase (APX) and glutathione reductase (GR) activity that were found to be stimulated. While, dehydroascorabte reductase (DHAR) activity, and the amount of metabolites: ascorbate (AsA), glutathione (GSH) and ratios of reduced/oxidized AsA (AsA/DHA) and GSH (GSH/GSSG), showed significant reduction with increasing doses of both the stressors, either applied alone or in combination. Glutathione-S-transferase (GST), an enzyme involved in scavenging of xenobiotics, was found to be stimulated under the tested stress. This study suggests that decline in DHAR activity and in AsA/DHA ratio might have led to enhanced H2O2 accumulation, thus decreased RGR was noticed under tested stress in both the species and the effect was more pronounced in A. pinnata. Owing to better performance of AsA-GSH cycle in A. microphylla, this study substantiates the view that A. microphylla is more tolerant than A. pinnata. Copyright © 2016 Elsevier Inc. All rights reserved.

Exogenous ascorbic acid improves defence responses of sunflower (Helianthus annuus) exposed to multiple stresses.

Science.gov (United States)

Kaya, Armagan

2017-09-01

Ascorbic acid is an important antioxidant that plays role both on growth and development and also stress response of the plant. The purpose of this study was to determine the effect of ascorbate on physiological and biochemical changes of sunflower that was exposed to multiple stresses. Chlorophyll and carotenoid contents decreased and glutathione, ascorbate and malondialdehyde contents as well as antioxidant enzyme activities increased for sunflower plant that was exposed to 50 mM NaCl and pendimethalin at different concentrations. These changes were found to be more significant in groups simultaneously exposed to both stress factors. While malondialdehyde content decreased, chlorophyll, carotenoid, ascorbate, glutathione contents and antioxidant enzyme activities increased in plants treated exogenously with ascorbate, compared to the untreated samples. According to the findings of our study; compared to individual stress, the effect of stress is more pronounced in sunflower exposed to multiple stresses, and treatment with exogenous ascorbate reduces the negative effects of stress.

Mitochondria, Energy and Cancer: The Relationship with Ascorbic Acid

Science.gov (United States)

González, Michael J.; Rosario-Pérez, Glorivee; Guzmán, Angélica M.; Miranda-Massari, Jorge R.; Duconge, Jorge; Lavergne, Julio; Fernandez, Nadia; Ortiz, Norma; Quintero, Ana; Mikirova, Nina; Riordan, Neil H.; Ricart, Carlos M.

2012-01-01

Ascorbic Acid (AA) has been used in the prevention and treatment of cancer with reported effectiveness. Mitochondria may be one of the principal targets of ascorbate's cellular activity and it may play an important role in the development and progression of cancer. Mitochondria, besides generating adenosine triphosphate (ATP), has a role in apoptosis regulation and in the production of regulatory oxidative species that may be relevant in gene expression. At higher concentrations AA may increase ATP production by increasing mitochondrial electron flux, also may induce apoptotic cell death in tumor cell lines, probably via its pro-oxidant action In contrast, at lower concentrations AA displays antioxidant properties that may prevent the activation of oxidant-induced apoptosis. These concentration dependent activities of ascorbate may explain in part the seemingly contradictory results that have been reported previously. PMID:23565030

Heat stable peroxidases from Vigna species (V) | Mbassi | African ...

African Journals Online (AJOL)

Shoots of three landraces of a Vigna species from two climatic areas of Cameroon were evaluated for their content of heat-resistant peroxidases. The peroxidase activity in the three landraces was detected with a greater catalytic efficiency for oxidation of O-dianisidine relative to ABTS (2, 2'-azino-bis-(3- ...

Magnetic resonance spectral characterization of the heme active site of Coprinus cinereus peroxidase

International Nuclear Information System (INIS)

Lukat, G.S.; Rodgers, K.R.; Jabro, M.N.; Goff, H.M.

1989-01-01

Examination of the peroxidase isolated from the inkcap Basidiomycete Coprinus cinereus shows that the 42,000-dalton enzyme contains a protoheme IX prosthetic group. Reactivity assays and the electronic absorption spectra of native Coprinus peroxidase and several of its ligand complexes indicate that this enzyme has characteristics similar to those reported for horseradish peroxidase. In this paper, the authors characterize the H 2 O 2 -oxidized forms of Coprinus peroxidase compounds I, II, and III by electronic absorption and magnetic resonance spectroscopies. Electron paramagnetic resonance (EPR) and nuclear magnetic resonance (NMR) studies of this Coprinus peroxidase indicate the presence of high-spin Fe(III) in the native protein and a number of differences between the heme site of Coprinus peroxidase and horseradish peroxidase. Carbon-13 (of the ferrous CO adduct) and nitrogen-15 (of the cyanide complex) NMR studies together with proton NMR studies of the native and cyanide-complexed Caprinus peroxidase are consistent with coordination of a proximal histidine ligand. The EPR spectrum of the ferrous NO complex is also reported. Protein reconstitution with deuterated hemin has facilitated the assignment of the heme methyl resonances in the proton NMR spectrum

Cafeteria diet induces obesity and insulin resistance associated with oxidative stress but not with inflammation: improvement by dietary supplementation with a melon superoxide dismutase.

Science.gov (United States)

Carillon, Julie; Romain, Cindy; Bardy, Guillaume; Fouret, Gilles; Feillet-Coudray, Christine; Gaillet, Sylvie; Lacan, Dominique; Cristol, Jean-Paul; Rouanet, Jean-Max

2013-12-01

Oxidative stress is involved in obesity. However, dietary antioxidants could prevent oxidative stress-induced damage. We have previously shown the preventive effects of a melon superoxide dismutase (SODB) on oxidative stress. However, the mechanism of action of SODB is still unknown. Here, we evaluated the effects of a 1-month curative supplementation with SODB on the liver of obese hamsters. Golden Syrian hamsters received either a standard diet or a cafeteria diet composed of high-fat, high-sugar, and high-salt supermarket products, for 15 weeks. This diet resulted in insulin resistance and in increased oxidative stress in the liver. However, inflammatory markers (IL-6, TNF-α, and NF-κB) were not enhanced and no liver steatosis was detected, although these are usually described in obesity-induced insulin resistance models. After the 1-month supplementation with SODB, body weight and insulin resistance induced by the cafeteria diet were reduced and hepatic oxidative stress was corrected. This could be due to the increased expression of the liver antioxidant defense proteins (manganese and copper/zinc superoxide dismutase, catalase, and glutathione peroxidase). Even though no inflammation was detected in the obese hamsters, inflammatory markers were decreased after SODB supplementation, probably through the reduction of oxidative stress. These findings suggest for the first time that SODB could exert its antioxidant properties by inducing the endogenous antioxidant defense. The mechanisms underlying this induction need to be further investigated. Copyright © 2013 Elsevier Inc. All rights reserved.

The cDNA sequence of a neutral horseradish peroxidase.

Science.gov (United States)

Bartonek-Roxå, E; Eriksson, H; Mattiasson, B

1991-02-16

A cDNA clone encoding a horseradish (Armoracia rusticana) peroxidase has been isolated and characterized. The cDNA contains 1378 nucleotides excluding the poly(A) tail and the deduced protein contains 327 amino acids which includes a 28 amino acid leader sequence. The predicted amino acid sequence is nine amino acids shorter than the major isoenzyme belonging to the horseradish peroxidase C group (HRP-C) and the sequence shows 53.7% identity with this isoenzyme. The described clone encodes nine cysteines of which eight correspond well with the cysteines found in HRP-C. Five potential N-glycosylation sites with the general sequence Asn-X-Thr/Ser are present in the deduced sequence. Compared to the earlier described HRP-C this is three glycosylation sites less. The shorter sequence and fewer N-glycosylation sites give the native isoenzyme a molecular weight of several thousands less than the horseradish peroxidase C isoenzymes. Comparison with the net charge value of HRP-C indicates that the described cDNA clone encodes a peroxidase which has either the same or a slightly less basic pI value, depending on whether the encoded protein is N-terminally blocked or not. This excludes the possibility that HRP-n could belong to either the HRP-A, -D or -E groups. The low sequence identity (53.7%) with HRP-C indicates that the described clone does not belong to the HRP-C isoenzyme group and comparison of the total amino acid composition with the HRP-B group does not place the described clone within this isoenzyme group. Our conclusion is that the described cDNA clone encodes a neutral horseradish peroxidase which belongs to a new, not earlier described, horseradish peroxidase group.

Melatonin treatment attenuates postharvest decay and maintains nutritional quality of strawberry fruits (Fragaria×anannasa cv. Selva) by enhancing GABA shunt activity.

Science.gov (United States)

Aghdam, Morteza Soleimani; Fard, Javad Rezapour

2017-04-15

Fresh strawberry fruits as perishable commodities have a short postharvest life and are prone to postharvest fungal decay. In this study, the impact of 0, 1, 10, 100 and 1000μmol/L melatonin on attenuating fungal decay and maintaining nutritional quality of strawberry fruits was investigated during storage at 4°C for 12days. Melatonin treatment at 100μmol/L triggered H 2 O 2 accumulation, which result from higher superoxide dismutase (SOD) activity, associated with lower catalase (CAT) and ascorbate peroxidase (APX) activities, leading to fruits with lower decay. Higher H 2 O 2 accumulation was concurrent with higher phenylalanine ammonia lyase (PAL) enzyme activity leading to higher total phenols and anthocyanins accumulation along with higher DPPH scavenging capacity. Also, strawberry fruits treated with melatonin exhibited higher γ-aminobutyric acid transaminase (GABA-T) enzyme activity which ensured sufficient ATP supplying leading to higher unsaturated/saturated fatty acids (unSFA/SFA) ratio. Copyright © 2016 Elsevier Ltd. All rights reserved.

Evidence against a direct role for oxidative stress in cadmium-induced axial malformation in the chick embryo

International Nuclear Information System (INIS)

Thompson, Jennifer; Doi, Takashi; Power, Eoin; Balasubramanian, Ishwarya; Puri, Prem; Bannigan, John

2010-01-01

Cadmium (Cd) is a powerful inducer of oxidative stress. It also causes ventral body wall defects in chick embryos treated at Hamburger-Hamilton stages 16-17. By measuring malondialdehyde levels (TBARS method) and cotreating with antioxidants (tempol, ascorbate, and N-acetylcysteine), we sought to determine if oxidative stress were directly related to teratogenesis. We also investigated the expression of mRNAs for antioxidant enzymes superoxide dismutase (SOD) -1 and -2, catalase (CAT), and glutathione peroxidase (GPx). RT-PCR showed reductions in SOD-1, SOD-2, and CAT 1 hour after treatment with Cd. MDA levels increased 4 hours after Cd, and remained elevated 24 hours after treatment. Of the antioxidants, only N-acetylcysteine reduced MDA levels to control values. Nonetheless, no antioxidant could reduce embryo lethality or malformation rates. Furthermore, MDA levels 24 hours after treatment were identical in malformed and normal embryos exposed to Cd. Hence, we conclude that oxidative stress may not have a direct role in Cd teratogenesis.

Aqueous Extract of Phyllanthus niruri Leaves Displays In Vitro Antioxidant Activity and Prevents the Elevation of Oxidative Stress in the Kidney of Streptozotocin-Induced Diabetic Male Rats

Directory of Open Access Journals (Sweden)

Nelli Giribabu

2014-01-01

Full Text Available P. niruri has been reported to possess antidiabetic and kidney protective effects. In the present study, the phytochemical constituents and in vitro antioxidant activity of P. niruri leaf aqueous extract were investigated together with its effect on oxidative stress and antioxidant enzymes levels in diabetic rat kidney. Results. Treatment of diabetic male rats with P. niruri leaf aqueous extract (200 and 400 mg/kg for 28 consecutive days prevents the increase in the amount of lipid peroxidation (LPO product, malondialdehyde (MDA, and the diminution of superoxide dismutase (SOD, catalase (CAT, and glutathione peroxidase (GPx activity levels in the kidney of diabetic rats. The amount of LPO showed strong negative correlation with SOD, CAT, and GPx activity levels. P. niruri leaf aqueous extract exhibits in vitro antioxidant activity with IC50 slightly lower than ascorbic acid. Phytochemical screening of plant extract indicates the presence of polyphenols. Conclusion. P. niruri leaf extract protects the kidney from oxidative stress induced by diabetes.

Induction of radiation resistance and radio-protective mechanism. On the reactive oxygen and free radical

International Nuclear Information System (INIS)

Yukawa, Osami

2003-01-01

Radical scavenging system for reactive oxygen species (ROS) leading to radio-protection is reviewed on findings in animals, tissues and cells. Protection against oxygen toxicity in evolution can be seen in anaerobes' superoxide dismutase (SOD) over 3500 million years ago. ROS is generated endogenously and also by radiation. However, the intracellular sites of the generated ROS are different depending on its cause. The protection is done through enzymes like SOD, peroxidase, catalase, glutathione-related enzymes and through substances like GSH, α-tocopherol, ascorbic acid etc. Induction of ROS scavenging substances related with radio-resistance includes the responses to the low dose radiation (5-50 cGy) in those enzymes described above; to middle to high dose radiation (1-30 Gy) in a similar and in other unknown mechanisms; to exposure of ROS like H 2 O 2 at low concentration; and to antioxidant treatment. The cross-resistance between radiation and drugs suggests necessity of this induction. (N.I.)

The perspective effects of various seed coating substances on rice seed variety Khao Dawk Mali 105 storability II: the case study of chemical and biochemical properties.

Science.gov (United States)

Thobunluepop, P; Pan-in, W; Pawelzik, E; Vearasilp, S

2009-04-01

The aim of this study was to investigate the effects of seed coating substances; chemical fungicide (CA) and biological fungicide polymers [chitosan-lignosulphonate polymer (CL) and eugenol incorporated into chitosan-lignosulphonate polymer (E+CL)] on chemical and biochemical changes of rice seeds cv. KDML 105, which have been studied during storage for 12 months. CA significantly affected the rice seed chemical properties and the associated seed deterioration. After 12 months storage, protein content decreased accompanied by declined of lipid content, increased free fatty acids and activated lipoxygenase enzyme. In the case of biological fungicide coated seeds, the antioxidative scavenging enzymes were ascorbate peroxidase and superoxide dismutase and a high antioxidant activity protected them. Moreover, the sugar content was positive correlated with seed germination and vigor. The biological coated seeds were found to maintain high sugar contents inside the seeds, which resulted high seed storability significantly. In contrast, under fungicide stress (CA), those compounds were lost that directly affected seed vigor during storage.

Biochemical analysis of reactive oxygen species production and antioxidative responses in unripe avocado (Persea americana Mill var Hass) fruits in response to wounding.

Science.gov (United States)

Castro-Mercado, E; Martinez-Diaz, Y; Roman-Tehandon, N; Garcia-Pineda, E

2009-03-01

We analyzed the production of reactive oxygen species (ROS) and of detoxifying enzymes and enzymes of the ascorbate (ASC) acid cycle in avocado fruit (Pesea Americana Mill cv Hass) in response to wounding. The levels of superoxide anion (O(2-), hydroxyl radicals (OH.) and hydrogen peroxide (H(2)O(2)) increased at 15 min and 2 and 15 h post-wounding. Peroxidase (POD) activity had increased to high levels 24 h after wounding; in contrast, catalase and superoxide dismutase (SOD) levels hat decreased significantly at 24 h post-treatment. Basic POD was the major POD form induced, and the levels of at least three apoplastic POD isozymes -increased following wounding. Using specific inhibitors, we characterized one MnSOD and two CuZnSOD isozymes. CuZnSOD activities decreased notably 12 h after treatment. The activities of dehydroascorbate reductase and glutathione reductase increased dramatically following the wounding treatment, possibly as a means to compensate for the redox changes due to ROS production.

Hepatic and erythrocytic glutathione peroxidase activity in liver diseases.

Science.gov (United States)

Cordero, R; Ortiz, A; Hernández, R; López, V; Gómez, M M; Mena, P

1996-09-01

Hepatic and erythrocytic glutathione peroxidase activity, together with malondialdehyde levels, were determined as indicators of peroxidation in 83 patients from whom liver biopsies had been taken for diagnostic purposes. On histological study, the patients were classified into groups as minimal changes (including normal liver), steatosis, alcoholic hepatitis, hepatic cirrhosis, light to moderately active chronic hepatitis, and severe chronic active hepatitis. The glutathione peroxidase activity in erythrocytes showed no significant changes in any liver disease group. In the hepatic study, an increased activity was observed in steatosis with respect to the minimal changes group, this increased activity induced by the toxic agent in the initial stages of the alcoholic hepatic disease declining as the hepatic damage progressed. There was a negative correlation between the levels of hepatic malondialdehyde and hepatic glutathione peroxidase in subjects with minimal changes. This suggested the existence of an oxidative equilibrium in this group. This equilibrium is broken in the liver disease groups as was manifest in a positive correlation between malondialdehyde and glutathione peroxidase activity.

Ascorbic acid and melatonin reduce heat-induced performance inhibition and oxidative stress in Japanese quails.

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Sahin, N; Onderci, M; Sahin, K; Gursu, M F; Smith, M O

2004-02-01

1. The effects of ascorbic acid (L-ascorbic acid) and melatonin supplementation on performance, carcase characteristics, malondialdehyde (MDA) as lipid peroxidation indicator, ascorbic acid, retinol, tocopherol and mineral status in the Japanese quail (Coturnix coturnix japonica) exposed to high ambient temperature were evaluated. 2. Two hundred and forty Japanese quails (10 d old) were randomly assigned to 8 treatment groups consisting of 10 replicates of three birds each. The birds were kept in a temperature-controlled room at 22 degrees C (Thermoneutral, TN groups) or 34 degrees C (for 8 h/d; 09:00 to 17:00 h; Heat stress, HS groups). Birds in both TN and HS were fed either a basal (control) diet or the basal diet supplemented with 250 mg of L-ascorbic acid/kg of diet (Ascorbic acid group), 40 mg of melatonin/kg of diet (Melatonin group) or both (Ascorbic acid + Melatonin group). 3. Supplementing heat-stressed quails with ascorbic acid and melatonin improved performance compared with the control group. Effects generally were greatest in quails supplemented with both ascorbic acid and melatonin. 4. Although supplementation did not consistently restore the concentrations of serum ascorbic acid, retinol and tocopherol to those of TN groups, these concentrations increased significantly with supplementation. Furthermore, serum and liver MDA and serum cholesterol and glucose concentrations were lower in the supplemented groups than in the heat-stressed controls. 5. Within each environment, excretion of Ca, P, Mg, Zn, Fe and Cr were lowest in the combination group and, in all cases, highest in the HS group. Interactions between diet and temperature were detected for live weight gain, cold carcase weight, MDA, ascorbic acid, tocopherol concentrations and excretion of zinc. 6. The results of the study indicate that ascorbic acid and melatonin supplementation attenuate the decline in performance and antioxidant and mineral status caused by heat stress and such

Effect of yogic exercise on superoxide dismutase levels in diabetics

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Mahapure Hemant

2008-01-01

Full Text Available Context: Reactive oxygen species are known to aggravate disease progression. To counteract their harmful effects, the body produces various antioxidant enzymes, viz , superoxide dismutase, glutathione reductase etc. Literature reviews revealed that exercises help to enhance antioxidant enzyme systems; hence, yogic exercises may be useful to combat various diseases. Aims: This study aims to record the efficacy of yoga on superoxide dismutase, glycosylated hemoglobin (Hb and fasting blood glucose levels in diabetics. Settings and Design: Forty diabetics aged 40-55 years were assigned to experimental (30 and control (10 groups. The experimental subjects underwent a Yoga program comprising of various Asanas (isometric type exercises and Pranayamas (breathing exercises along with regular anti-diabetic therapy whereas the control group received anti-diabetic therapy only. Methods and Material: Heparinized blood samples were used to determine erythrocyte superoxide dismutase (SOD activity and glycosylated Hb levels and fasting blood specimens collected in fluoride Vacutainers were used for assessing blood glucose. Statistical analysis used: Data were analyzed by using 2 x 2 x 3 Factorial ANOVA followed by Scheffe′s posthoc test. Results: The results revealed that Yogic exercise enhanced the levels of Superoxide dismutase and reduced glycosylated Hb and glucose levels in the experimental group as compared to the control group. Conclusion: The findings conclude that Yogic exercises have enhanced the antioxidant defence mechanism in diabetics by reducing oxidative stress.

The preparation and the sustained release of titanium dioxide hollow particles encapsulating L-ascorbic acid

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Tominaga, Yoko; Kadota, Kazunori; Shimosaka, Atsuko; Yoshida, Mikio; Oshima, Kotaro; Shirakawa, Yoshiyuki

2018-05-01

The preparation of the titanium dioxide hollow particles encapsulating L-ascorbic acid via sol-gel process using inkjet nozzle has been performed, and the sustained release and the effect protecting against degradation of L-ascorbic acid in the particles were investigated. The morphology of titanium dioxide particles was evaluated by scanning electron microscopy (SEM) and energy dispersive X-ray spectrometry (EDS). The sustained release and the effect protecting against degradation of L-ascorbic acid were estimated by dialysis bag method in phosphate buffer saline (PBS) (pH = 7.4) as release media. The prepared titanium dioxide particles exhibited spherical porous structures. The particle size distribution of the titanium dioxide particles was uniform. The hollow titanium dioxide particles encapsulating L-ascorbic acid showed the sustained release. It was also found that the degradation of L-ascorbic acid could be inhibited by encapsulating L-ascorbic acid in the titanium dioxide hollow particles.

Overexpressing the Sedum alfredii Cu/Zn Superoxide Dismutase Increased Resistance to Oxidative Stress in Transgenic Arabidopsis

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Zhen Li

2017-06-01

Full Text Available Superoxide dismutase (SOD is a very important reactive oxygen species (ROS-scavenging enzyme. In this study, the functions of a Cu/Zn SOD gene (SaCu/Zn SOD, from Sedum alfredii, a cadmium (Cd/zinc/lead co-hyperaccumulator of the Crassulaceae, was characterized. The expression of SaCu/Zn SOD was induced by Cd stress. Compared with wild-type (WT plants, overexpression of SaCu/Zn SOD gene in transgenic Arabidopsis plants enhanced the antioxidative defense capacity, including SOD and peroxidase activities. Additionally, it reduced the damage associated with the overproduction of hydrogen peroxide (H2O2 and superoxide radicals (O2•-. The influence of Cd stress on ion flux across the root surface showed that overexpressing SaCu/Zn SOD in transgenic Arabidopsis plants has greater Cd uptake capacity existed in roots. A co-expression network based on microarray data showed possible oxidative regulation in Arabidopsis after Cd-induced oxidative stress, suggesting that SaCu/Zn SOD may participate in this network and enhance ROS-scavenging capability under Cd stress. Taken together, these results suggest that overexpressing SaCu/Zn SOD increased oxidative stress resistance in transgenic Arabidopsis and provide useful information for understanding the role of SaCu/Zn SOD in response to abiotic stress.

Chromium-induced membrane damage: protective role of ascorbic acid.

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Dey, S K; Nayak, P; Roy, S

2001-07-01

Importance of chromium as environmental toxicant is largely due to impact on the body to produce cellular toxicity. The impact of chromium and their supplementation with ascorbic acid was studied on plasma membrane of liver and kidney in male Wistar rats (80-100 g body weight). It has been observed that the intoxication with chromium (i.p.) at the dose of 0.8 mg/100 g body weight per day for a period of 28 days causes significant increase in the level of cholesterol and decrease in the level of phospholipid of both liver and kidney. The alkaline phosphatase, total ATPase and Na(+)-K(+)-ATPase activities were significantly decreased in both liver and kidney after chromium treatment, except total ATPase activity of kidney. It is suggested that chromium exposure at the present dose and duration induce for the alterations of structure and function of both liver and kidney plasma membrane. Ascorbic acid (i.p. at the dose of 0.5 mg/100 g body weight per day for period of 28 days) supplementation can reduce these structural changes in the plasma membrane of liver and kidney. But the functional changes can not be completely replenished by the ascorbic acid supplementation in response to chromium exposure. So it is also suggested that ascorbic acid (nutritional antioxidant) is useful free radical scavenger to restrain the chromium-induced membrane damage.

Geomagnetic Field (Gmf) and Plant Evolution: Investigating the Effects of Gmf Reversal on Arabidopsis thaliana Development and Gene Expression.

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Bertea, Cinzia M; Narayana, Ravishankar; Agliassa, Chiara; Rodgers, Christopher T; Maffei, Massimo E

2015-11-30

One of the most stimulating observations in plant evolution is a correlation between the occurrence of geomagnetic field (GMF) reversals (or excursions) and the moment of the radiation of Angiosperms. This led to the hypothesis that alterations in GMF polarity may play a role in plant evolution. Here, we describe a method to test this hypothesis by exposing Arabidopsis thaliana to artificially reversed GMF conditions. We used a three-axis magnetometer and the collected data were used to calculate the magnitude of the GMF. Three DC power supplies were connected to three Helmholtz coil pairs and were controlled by a computer to alter the GMF conditions. Plants grown in Petri plates were exposed to both normal and reversed GMF conditions. Sham exposure experiments were also performed. Exposed plants were photographed during the experiment and images were analyzed to calculate root length and leaf areas. Arabidopsis total RNA was extracted and Quantitative Real Time-PCR (qPCR) analyses were performed on gene expression of CRUCIFERIN 3 (CRU3), copper transport protein1 (COTP1), Redox Responsive Transcription Factor1 (RRTF1), Fe Superoxide Dismutase 1, (FSD1), Catalase3 (CAT3), Thylakoidal Ascorbate Peroxidase (TAPX), a cytosolic Ascorbate Peroxidase1 (APX1), and NADPH/respiratory burst oxidase protein D (RbohD). Four different reference genes were analysed to normalize the results of the qPCR. The best of the four genes was selected and the most stable gene for normalization was used. Our data show for the first time that reversing the GMF polarity using triaxial coils has significant effects on plant growth and gene expression. This supports the hypothesis that GMF reversal contributes to inducing changes in plant development that might justify a higher selective pressure, eventually leading to plant evolution.

The humic acid-induced changes in the water status, chlorophyll fluorescence and antioxidant defense systems of wheat leaves with cadmium stress.

Science.gov (United States)

Ozfidan-Konakci, Ceyda; Yildiztugay, Evren; Bahtiyar, Mustafa; Kucukoduk, Mustafa

2018-07-15

The using of bio-stimulant in plants grown under stress conditions for enhancing nutrition efficiency and crop quality traits is an effective approach. One of the bio-stimulants, humus material, is defined as humic acid (HA). HA application as a promotion of plant growth to plants grown in the heavy metals-contaminated soils has promised hope in terms of effects on plants but the its limiting effect is the application dose. Therefore, the wheat seedlings were grown in hydroponic culture for 21 d and the various concentrations of humic acid (HA; 750 or 1500 mg L -1 ) were treated alone or in combination with cadmium (Cd) stress (100 or 200 μM) for 7 d. The results showed that after Cd stress treatment, water content (RWC), osmotic potential (Ψ Π ) and chlorophyll fluorescence parameters decreased and proline content (Pro) increased for 7 d. In spite of activated peroxidase (POX) and ascorbate peroxidase (APX), stress induced the toxic levels of hydrogen peroxide (H 2 O 2 ) accumulation. Cd stress triggered lipid peroxidation (TBARS content). HA application successfully eliminated the negative effects of stress on RWC, Ψ Π and photosynthetic parameters. In the presence of HA under stress, the increased activation of superoxide dismutase (SOD), catalase (CAT) and NADPH-oxidase (NOX) enzymes and ascorbate, glutathione and GSH/GSSG ratio observed. Only 750 mg L -1 HA under stress conditions induced the activities of monodehydroascorbate reductase (MDHAR) and dehydroascorbate reductase (DHAR), and dehydroascorbate (DHA) content. After the combined application of HA and Cd stress, the low contents of H 2 O 2 and TBARS maintained in wheat leaves. Hence, HA successfully eliminated the toxicity of Cd stress by modulating the water status, photosynthetic apparatus and antioxidant activity in wheat leaves. Copyright © 2018 Elsevier Inc. All rights reserved.

Candida albicans biofilm on titanium: effect of peroxidase precoating

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Mohamed Ahariz

2010-08-01

Full Text Available Mohamed Ahariz1, Philippe Courtois1,21Laboratory of Experimental Hormonology, Université Libre de Bruxelles, Brussels, 2UER de Biologie Médicale, Haute Ecole Francisco Ferrer, Brussels, BelgiumAbstract: The present study aimed to document Candida albicans biofilm development on titanium and its modulation by a peroxidase-precoated material which can generate antimicrobials, such as hypoiodite or hypothiocyanite, from hydrogen peroxide, iodide, or thiocyanate. For this purpose, titanium (powder or foil was suspended in Sabouraud liquid medium inoculated with C. albicans ATCC10231. After continuous stirring for 2–21 days at room temperature, the supernatant was monitored by turbidimetry at 600 nm and titanium washed three times in sterile Sabouraud broth. Using the tetrazolium salt MTT-formazan assay, the titanium-adherent fungal biomass was measured as 7.50 ± 0.60 × 106 blastoconidia per gram of titanium powder (n = 30 and 0.50 ± 0.04 × 106 blastoconidia per cm² of titanium foil (n = 12. The presence of yeast on the surface of titanium was confirmed by microscopy both on fresh preparations and after calcofluor white staining. However, in the presence of peroxidase systems (lactoperoxidase with substrates such as hydrogen peroxide donor, iodide, or thiocyanate, Candida growth in both planktonic and attached phases appeared to be inhibited. Moreover, this study demonstrates the possible partition of peroxidase systems between titanium material (peroxidase-precoated and liquid environment (containing peroxidase substrates to limit C. albicans biofilm formation.Keywords: adhesion, material, oral, yeast

Superoxide dismutase and catalase conjugated to polyethylene glycol increases endothelial enzyme activity and oxidant resistance

International Nuclear Information System (INIS)

Beckman, J.S.; Minor, R.L. Jr.; White, C.W.; Repine, J.E.; Rosen, G.M.; Freeman, B.A.

1988-01-01

Covalent conjugation of superoxide dismutase and catalase with polyethylene glycol (PEG) increases the circulatory half-lives of these enzymes from 125 I-PEG-catalase or 125 I-PEG-superoxide dismutase produced a linear, concentration-dependent increase in cellular enzyme activity and radioactivity. Fluorescently labeled PEG-superoxide dismutase incubated with endothelial cells showed a vesicular localization. Mechanical injury to cell monolayers, which is known to stimulate endocytosis, further increased the uptake of fluorescent PEG-superoxide dismutase. Addition of PEG and PEG-conjugated enzymes perturbed the spin-label binding environment, indicative of producing an increase in plasma membrane fluidity. Thus, PEG conjugation to superoxide dismutase and catalase enhances cell association of these enzymes in a manner which increases cellular enzyme activities and provides prolonged protection from partially reduced oxygen species

The effects of ascorbic acid on diphtheria toxin and intoxicated hela cells

International Nuclear Information System (INIS)

Clark, C.E.; Smith, T.J.

1976-01-01

Ascorbic acid (vitamin C) prevented diphtheria toxin from inhibiting the incorporation of [U- 14 C]-alanine into trichloroacetic acid precipitable material in HeLa cells. Ascorbic acid did not exhibit an effect on the adenosine diphosphate-ribosylation of amino acyl transferase 2 nor did it separate fragment A from fragment B in ''nicked'' toxin. A non-specific reducing agent, para-methylaminophenol sulfate, exhibited an effect of HeLa cells very similar to the results of ascorbic acid. Citric acid, a tricarboxylic acid, had no effect on HeLa cells. (auth.)

Study of radio-protective effects of ascorbic acid in rates

International Nuclear Information System (INIS)

Bakir, A.M.; Mohammad, A.

2011-06-01

The aim of this study was to evaluate the potential radio-protective effects of different ascorbic acid concentrations (vitamin C) in rats before whole body irradiation with total dose of 7 Gy ( 60 Co source) using two different dose rates of 1 and 0.55 Gy.min -1 by increasing percent of surviving. In the first group (1 Gy/m); rats were administered four different concentrations of ascorbic acid (7.5, 12.5, 100, 200 mg/kg b wt ) in drinking water for 30 days before irradiation starting from the ablactation which considered as day 0. Whereas, in the second group (0.55 Gy/m); rats were administered six different concentrations of ascorbic acid (1, 5, 7.5, 12.5, 100, 200 mg/kg b wt) before irradiation with total dose 7 Gy ( 60 Co source). The results have showed that the ascorbic acid enhance the 30-day survival of irradiated rats in 1 and 0.55 Gy/m groups, compared to the control group. The mean cumulated probability of survival of rats (1 Gy/m group) was 66%± 6 (Mean± S.E), 69%± 5, 52%± 9 and 51%± 9 in groups of rats which administered 7.5, 12.5, 100, 200 mg/kg, respectively, versus 41%± 9 in control group for 14 days. While, it was 90%± 2, 90%± 2, 88%± 2, 94%± 1, 84%± 3 and 78%± 3 in groups of rats which administered 1, 5, 7.5, 12.5, 100, 200 mg/kg respectively, versus 52%± 6 in control group for 30 days. Our data, also, indicated that all ascorbic acid concentrations in both groups had significant reduction in mortality and increasing percent of surviving compared to the control groups. We conclude that all ascorbic acid concentrations which used in both groups (1 and 0.55 Gy/m), had radioprotective effects in rats when administrated before irradiations, and this role was more effective against lower dose rate of radiation exposure. (author)

Ascorbate availability affects tumor implantation-take rate and increases tumor rejection in Gulo–/– mice

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Campbell EJ

2016-04-01

Full Text Available Elizabeth J Campbell,1 Margreet CM Vissers,2 Gabi U Dachs1 1Mackenzie Cancer Research Group, 2Centre for Free Radical Research, Department of Pathology, University of Otago, Christchurch, New Zealand Abstract: In solid tumors, HIF1 upregulates the expression of hundreds of genes involved in cell survival, tumor growth, and adaptation to the hypoxic microenvironment. HIF1 stabilization and activity are suppressed by prolyl and asparagine hydroxylases, which require oxygen as a substrate and ascorbate as a cofactor. This has led us to hypothesize that intracellular ascorbate availability could modify the hypoxic HIF1 response and influence tumor growth. In this study, we investigated the effect of variable intracellular ascorbate levels on HIF1 induction in cancer cells in vitro, and on tumor-take rate and growth in the Gulo–/– mouse. These mice depend on dietary ascorbate, and were supplemented with 3,300 mg/L, 330 mg/L, or 33 mg/L ascorbate in their drinking water, resulting in saturating, medium, or low plasma and tissue ascorbate levels, respectively. In Lewis lung carcinoma cells (LL/2 in culture, optimal ascorbate supplementation reduced HIF1 accumulation under physiological but not pathological hypoxia. LL/2, B16-F10 melanoma, or CMT-93 colorectal cancer cells were implanted subcutaneously into Gulo–/– mice at a range of cell inocula. Establishment of B16-F10 tumors in mice supplemented with 3,300 mg/L ascorbate required an increased number of cancer cells to initiate tumor growth compared with the number of cells required in mice on suboptimal ascorbate intake. Elevated ascorbate intake was also associated with decreased tumor ascorbate levels and a reduction in HIF1α expression and transcriptional activity. Following initial growth, all CMT-93 tumors regressed spontaneously, but mice supplemented with 33 mg/L ascorbate had lower plasma ascorbate levels and grew larger tumors than optimally supplemented mice. The data from this

Ascorbic acid reduces noise-induced nitric oxide production in the guinea pig ear.

Science.gov (United States)

Heinrich, Ulf-Rüdiger; Fischer, Ilka; Brieger, Jürgen; Rümelin, Andreas; Schmidtmann, Irene; Li, Huige; Mann, Wolf J; Helling, Kai

2008-05-01

Noise-induced hearing loss can be caused, among other causes, by increased nitric oxide (NO) production in the inner ear leading to nitroactive stress and cell destruction. Some studies in the literature suggest that the degree of hearing loss (HL) could be reduced in an animal model through ascorbic acid supplementation. To identify the effect of ascorbic acid on tissue-dependent NO content in the inner ear of the guinea pig, we determined the local NO production in the organ of Corti and the lateral wall separately 6 hours after noise exposure. Prospective animal study in guinea pigs. Over a period of 7 days, male guinea pigs were supplied with minimum (25 mg/kg body weight/day) and maximum (525 mg/kg body weight/day) ascorbic acid doses, and afterwards exposed to noise (90 dB sound pressure level for 1 hour). The acoustic-evoked potentials were recorded before and after noise exposure. The organ of Corti and the lateral wall were incubated differently for 6 hours in culture medium, and the degree of NO production was determined by chemiluminescence. Ascorbic acid treatment reduced the hearing threshold shift after noise exposure depending on concentration. When the maximum ascorbic acid dose was substituted, NO production was significantly reduced in the lateral wall after noise exposure and slightly reduced in the organ of Corti. Oral supplementation of the natural radical scavenger ascorbic acid reduces the NO-production rate in the inner ear in noisy conditions. This finding supports the concept of inner ear protection by ascorbic acid supplementation.

A catalytic approach to estimate the redox potential of heme-peroxidases

International Nuclear Information System (INIS)

Ayala, Marcela; Roman, Rosa; Vazquez-Duhalt, Rafael

2007-01-01

The redox potential of heme-peroxidases varies according to a combination of structural components within the active site and its vicinities. For each peroxidase, this redox potential imposes a thermodynamic threshold to the range of oxidizable substrates. However, the instability of enzymatic intermediates during the catalytic cycle precludes the use of direct voltammetry to measure the redox potential of most peroxidases. Here we describe a novel approach to estimate the redox potential of peroxidases, which directly depends on the catalytic performance of the activated enzyme. Selected p-substituted phenols are used as substrates for the estimations. The results obtained with this catalytic approach correlate well with the oxidative capacity predicted by the redox potential of the Fe(III)/Fe(II) couple

Control of lethal browning by using ascorbic acid on shoot tip ...

African Journals Online (AJOL)

The use of ascorbic acid during explants preparation and the effect of different concentrations of ascorbic acid in controlling lethal browning and survival of the explants in local banana cv. Mzuzu banana were investigated. The explants were taken from young suckers. The shoot tips were cultured on Murashige and Skoog's ...

Purification and Characterization of Polyphenol Oxidase, Peroxidase and Lipoxygenase from Freshly Cut Lettuce (L. sativa

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Vural Gökmen

2011-01-01

Full Text Available Enzymatic reactions taking place in minimally processed vegetables are considered as a major problem, because they adversely affect sensorial and nutritional quality. Polyphenol oxidase (PPO, peroxidase (POD and lipoxygenase (LOX from lettuce were purified on a column packed with positively charged diethylaminoethyl (DEAE cellulose by applying pH gradient elution from pH=4.0 to 9.0. The main purified fractions (PPO1 and PPO4, POD1 and POD2, LOX1 and LOX2 were characterized for enzyme concentration-reaction rate relationship, thermal stability, pH activity and kinetic parameters. Kinetic properties of each isoform were considerably different. Cysteine was found as the most effective inhibitor of both fractions of PPO. Kinetic parameters of lettuce POD were presented using guaiacol at various H2O2 concentrations. β-carotene directly influences lettuce LOX in the reaction medium available for the catalytic conversion of linoleic acid into hydroperoxides. Ascorbic and oxalic acids appear as effective PPO inhibitors, protecting phenolic compounds against oxidation in lettuce. Understanding the characteristics of deteriorative enzymes becomes important to maintain suitable conditions for fresh-like quality of lettuce. The results can be useful to keep the nutritional quality of minimally processed lettuce during shelf-life.

A highly sensitive kinetic spectrophotometric method for the determination of ascorbic Acid in pharmaceutical samples.

Science.gov (United States)

Shishehbore, Masoud Reza; Aghamiri, Zahra

2014-01-01

In this study, a new reaction system for quantitative determination of ascorbic acid was introduced. The developed method is based on inhibitory effect of ascorbic acid on the Orange G-bromate system. The change in absorbance was followed spectrophotometrically at 478 nm. The dependence of sensitivity on the reaction variables including reagents concentration, temperature and time was investigated. Under optimum experimental conditions, calibration curve was linear over the range 0.7 - 33.5 μg mL(-1) of ascorbic acid including two linear segments and the relative standard deviations (n = 6) for 5.0 and 20.0 μg mL(-1) of ascorbic acid were 1.08 and 1.02%, respectively. The limit of detection was 0.21 μg mL(-) (1) of ascorbic acid. The effect of diverse species was also investigated. The developed method was successfully applied for the determination of ascorbic acid in pharmaceutical samples. The results were in a good agreement with those of reference method.

Peroxidase synthesis and activity in the interaction of soybean with Phytophthora megasperma f. sp. glycinea (Pmg)

International Nuclear Information System (INIS)

Chibbar, R.N.; Esnault, R.; Lee, D.; van Huystee, R.B.; Ward, E.W.B.

1986-01-01

Changes, in peroxidase (EC1.11.1.7) have been reported following infection. However, determinations of biosynthesis of quantities of the peroxidase protein molecule have not been made! In this study hypocotyl of soybean seedlings (Glycine max; cv Harosoy, susceptible; cv Harosoy 63, resistant) were inoculated with zoospores of Pmg. Incorporation of 35 S-methionine (supplied with inoculum) in TCA precipitates was measured. Peroxidase synthesis was measured by immuno precipitation using antibodies against a cationic and an anionic peroxidase derived from peanut cells. Specific peroxidase activity increased rapidly from 5 to 9 h following infection in the resistant reaction but not in the susceptible reaction or the water controls. There was increased synthesis of the anionic peroxidase but not of the cationic peroxidase in the resistant reaction. The anionic peroxidase did not increase in the susceptible until 15 h. The ratio of peroxidase synthesis to total protein synthesis decreased in inoculated tissues compared to control. Peroxidase synthesis is, therefore, a relative minor host response to infection

Purification and characterization of lignin peroxidases from Penicillium decumbens P6

Energy Technology Data Exchange (ETDEWEB)

Yang, J.S.; Yuan, H.L.; Wang, H.X.; Chen, W.X. [China Agricultural University, Beijing (China). College of Biological Science

2005-06-01

Peroxidases are essential enzymes in biodegradation of lignin and lignite which have been investigated intensively in the white-rot fungi. This is the first report of purification and characterization of lignin peroxidase from Penicillium sp. P6 as lignite degradation fungus. The results indicated that the lignin peroxidase of Penicillium decumbens P6 had physical and chemical properties and a N-terminal amino acid sequence different from the lignin peroxidases of white-rot fungi. The lignin peroxidase was isolated from a liquid culture of P. decumbens P6. This enzyme had a molecular weight of 46.3 KDa in SDS-PAGE and exhibited greater activity, temperature stability and wider pH range than those previously reported. The isolation procedure involved (NH{sub 4}){sub 2}SO{sub 4} precipitation, ion-exchange chromatography on DEAE-cellulose and CM-cellulose, gel filtration on Sephadex G-100, and non-denaturing, discontinuous polyacrylamide gel electrophoresis. The K{sub m} and V{sub max} values of this enzyme using veratryl alcohol as substrate were 0.565 mmol L{sup -1} and 0.088 mmol (mg protein){sup -1} min{sup -1} respectively. The optimum pH of P6 lignin peroxidase was 4.0, and 70.6% of the relative activity was remained at pH 9.0. The optimum temperature of the enzyme was 45{sup o}C.

Factors that affect leaf extracellular ascorbic acid content and redox status

Energy Technology Data Exchange (ETDEWEB)

Burkey, K.O.; Fiscus, E.L. [North Carolina State Univ., United States dept. og Agriculture-Agricultural Research Service and Dept. of Crop Science, Raleigh, NC (United States); Eason, G. [North Carolina, State Univ., United States Dept. of Plant Pathology, Raleigh, NC (United States)

2003-01-01

Leaf ascorbic acid content and redox status were compared in ozone-tolerant (Provider) and ozone-sensitive (S156) genotypes of snap bean (Phaseolus vulgaris L.). Plants were grown in pots for 24 days under charcoal-filtered air (CF) conditions in open-top field chambers and then maintained as CF controls (29 nmol mol{sup 1} ozone) or exposed to elevated ozone (71 nmol mol{sup 1} ozone). Following a 10-day treatment, mature leaves of the same age were harvested early in the morning (06:00-08:00 h) or in the afternoon (13:00-15:00 h) for analysis of ascorbic acid (AA) and dehydroascorbic acid (DHA). Vacuum infiltration methods were used to separate leaf AA into apoplast and symplast fractions. The total ascorbate content [AA + DHA] of leaf tissue averaged 28% higher in Provider relative to S156, and Provider exhibited a greater capacity to maintain [AA + DHA] content under ozone stress. Apoplast [AA + DHA] content was 2-fold higher in tolerant Provider (360 nmol g{sup 1} FW maximum) relative to sensitive S156 (160 nmol g1 FW maximum) regardless of sampling period or treatment, supporting the hypothesis that extracellular AA is a factor in ozone tolerance. Apoplast [AA + DHA] levels were significantly higher in the afternoon than early morning for both genotypes, evidence for short-term regulation of extracellular ascorbate content. Total leaf ascorbate was primarily reduced with AA/[AA + DHA] ratios of 0.81-0.90. In contrast, apoplast AA/[AA + DHA] ratios were 0.01-0.60 and depended on genotype and ozone treatment. Provider exhibited a greater capacity to maintain extracellular AA/[AA + DHA] ratios under ozone stress, suggesting that ozone tolerance is associated with apoplast ascorbate redox status. (au)

Catalase and Superoxide Dismutase of Root-Colonizing Saprophytic Fluorescent Pseudomonads †

OpenAIRE

Katsuwon, Jirasak; Anderson, Anne J.

1990-01-01

Root-colonizing, saprophytic fluorescent pseudomonads of the Pseudomonas putida-P. fluorescens group express similar levels of catalase and superoxide dismutase activities during growth on a sucrose- and amino acid-rich medium. Increased specific activities of catalase but not superoxide dismutase were observed during growth of these bacteria on components washed from root surfaces. The specific activities of both enzymes were also regulated during contact of these bacteria with intact bean r...

Zymogram profiling of superoxide dismutase and catalase activities allows Saccharomyces and non-Saccharomyces species differentiation and correlates to their fermentation performance.

Science.gov (United States)

Gamero-Sandemetrio, Esther; Gómez-Pastor, Rocío; Matallana, Emilia

2013-05-01

Aerobic organisms have devised several enzymatic and non-enzymatic antioxidant defenses to deal with reactive oxygen species (ROS) produced by cellular metabolism. To combat such stress, cells induce ROS scavenging enzymes such as catalase, peroxidase, superoxide dismutase (SOD) and glutathione reductase. In the present research, we have used a double staining technique of SOD and catalase enzymes in the same polyacrylamide gel to analyze the different antioxidant enzymatic activities and protein isoforms present in Saccharomyces and non-Saccharomyces yeast species. Moreover, we used a technique to differentially detect Sod1p and Sod2p on gel by immersion in NaCN, which specifically inhibits the Sod1p isoform. We observed unique SOD and catalase zymogram profiles for all the analyzed yeasts and we propose this technique as a new approach for Saccharomyces and non-Saccharomyces yeast strains differentiation. In addition, we observed functional correlations between SOD and catalase enzyme activities, accumulation of essential metabolites, such as glutathione and trehalose, and the fermentative performance of different yeasts strains with industrial relevance.

On the protection of E.coli against radiation lethality by ascorbate combined with tetracycline

International Nuclear Information System (INIS)

Djalali-Behzad, G.; Ehrenberg, L.

1977-01-01

The radioprotective action in E.coli ATCC 9637 of ascorbate added to media containing the weak sensitizer, tetracycline (Pittillo, R.F., and Lucas, M.B., 1967, Radiat. Res., vol. 31, 36) was found to be dependent on the presence of metal catalysts of the autoxidation of ascorbate. Thus, the protective action of ascorbate + tetracycline as well as the rate of autoxidation of ascorbate in this mixture were enhanced by 0.1 μM Cu, and these effects were counteracted by pyrophosphate probably through chelation of iron that contaminates phosphate. A suppression of metabolism is apparently involved in the combined action as judged by the decrease of incorporation of labelled uridine. (author)

Enzymatic Activity Enhancement of Non-Covalent Modified Superoxide Dismutase and Molecular Docking Analysis

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Fa-Jun Song

2012-03-01

Full Text Available The enzyme activity of superoxide dismutase was improved in the pyrogallol autoxidation system by about 27%, after interaction between hydroxypropyl-β-cyclo- dextrin and superoxide dismutase. Fluorescence spectrometry was used to study the interaction between hydroxypropyl-β-cyclodextrin and superoxide dismutase at different temperatures. By doing this, it can be found that these interactions increase fluorescence sensitivity. In the meantime, the synchronous fluorescence intensity revealed the interaction sites to be close to the tryptophan (Trp and tyrosine (Tyr residues of superoxide dismutase. Furthermore, molecular docking was applied to explore the binding mode between the ligands and the receptor. This suggested that HP-β-CD interacted with the B ring, G ring and the O ring and revealed that the lysine (Lys residues enter the nanocavity. It was concluded that the HP-β-CD caused specific conformational changes in SOD by non-covalent modification.

Apple and quince peroxidase activity in response to essential oils ...

African Journals Online (AJOL)

Enzymatic browning arises by peroxidase in fruits. However, essential oils are recognized as natural antioxidant agents. So in this study, the effect of thyme, coriander and rosemary essential oils were evaluated on the reduction of peroxidase activity in apples (Malus domestica Mill. cv Golden delicious), (M. domestica Mill.

Antinociceptive Properties of Ascorbic Acid: Evidence for the Mechanism of Action

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Zeraati

2014-09-01

Full Text Available Background Ascorbic acid is amongst important water-soluble vitamins and when used orally in high-doses it has been observed to relieve pain and reduce opioid use in patients. However no controlled trial has compared the antinociceptive effects of ascorbic acid with other analgesic groups on animal models, and investigated the involved mechanisms. Objectives In the present study, the antinociceptive effect of vitamin C on male mice was investigated and compared with morphine and diclofenac. Also, possible mechanisms were assayed. Materials and Methods Male albino mice were used in this study. Antinociception was measured using the writhing test, tail flick and formalin tests. Ascorbic acid was used in three doses (30, 150 and 300 mg/kg, IP and compared with the antinociceptive effects of 10 mg/kg of morphine as an opioid analgesic agent and 5-10 mg/kg of diclofenac as a nonsteroidal anti-inflammatory drug (NSAID analgesic agent.The antinociceptive effect of ascorbic acid (300 mg/kg was compared before and after treatment with naloxone (4 mg/kg, ondansetron (0.5 mg/kg, atropine (5 mg/kg and metoclopramide (1 mg/kg in the writhing test. Results Vitamin C caused dose-dependent antinociceptive effects in acetic acid writhing test (P < 0.05. It had no significant effect in the tail flick test. Meanwhile, vitamin C in high doses reduced pain in the second phase of the formalin test (P < 0.05. Morphine had higher nociceptive effects in comparison to ascorbic acid in the writhing test (P < 0.05. In the second phase of the formalin test the antinociceptive effects of vitamin C (300 mg/kg was not significantly different with morphine at dose of 10 mg/kg. There was not significant difference between vitamin C (300 mg/kg and diclofenac (10 mg/kg in the second phase of the formalin test. Metoclopramide and ondansetrone reduced the antinociceptive effects of vitamin C. Conclusions The results obtained from the acetic acid induced writhing test and second

Peroxidase-like activity of magnetoferritin

Czech Academy of Sciences Publication Activity Database

Melníková, V.; Pospíšková, K.; Mitróová, Z.; Kopčanský, P.; Šafařík, Ivo

2014-01-01

Roč. 181, 3-4 (2014), s. 295-301 ISSN 0026-3672 R&D Projects: GA MŠk(CZ) LD13021 Institutional support: RVO:67179843 Keywords : magnetoferritin * magnetic nanoparticles * peroxidase-like activity * hydrogen peroxide * oxidative stress Subject RIV: CE - Biochemistry Impact factor: 3.741, year: 2014

Ascorbic acid deficiency stimulates hepatic expression of inflammatory chemokine, cytokine-induced neutrophil chemoattractant-1, in scurvy-prone ODS rats.

Science.gov (United States)

Horio, Fumihiko; Kiyama, Keiichiro; Kobayashi, Misato; Kawai, Kaori; Tsuda, Takanori

2006-02-01

ODS rat has a hereditary defect in ascorbic acid biosynthesis and is a useful animal model for elucidating the physiological role of ascorbic acid. We previously demonstrated by using ODS rats that ascorbic acid deficiency changes the hepatic gene expression of acute phase proteins, as seen in acute inflammation. In this study, we investigated the effects of ascorbic acid deficiency on the production of inflammatory chemokine, cytokine-induced neutrophil chemoattractant-1 (CINC-1), in ODS rats. Male ODS rats (6 wk of age) were fed a basal diet containing ascorbic acid (300 mg/kg diet) or a diet without ascorbic acid for 14 d. Obvious symptoms of scurvy were not observed in the ascorbic acid-deficient rats. Ascorbic acid deficiency significantly elevated the serum concentration of CINC-1 on d 14. The liver and spleen CINC-1 concentrations in the ascorbic acid-deficient rats were significantly elevated to 600% and 180% of the respective values in the control rats. However, the lung concentration of CINC-1 was not affected by ascorbic acid deficiency. Ascorbic acid deficiency significantly elevated the hepatic mRNA level of CINC-1 (to 480% of the value in the control rats), but not the lung mRNA level. These results demonstrate that ascorbic acid deficiency elevates the serum, liver and spleen concentrations of CINC-1 as seen in acute inflammation, and suggest that ascorbic acid deficiency stimulate the hepatic CINC-1 gene expression.

Ascorbate and dehydroascorbic acid as reliable biomarkers of oxidative stress

DEFF Research Database (Denmark)

Lykkesfeldt, Jens

2007-01-01

, the analytical reproducibility was tested by repeated analysis of plasma aliquots from one individual over four years. The plasma was subjected to acidic deproteinization with an equal volume of 10% meta-phosphoric acid containing 2 mM EDTA and analyzed for ascorbate and dehydroascorbic acid by high-performance...... liquid chromatography with coulometric detection. In a parallel experiment, stability of human plasma samples treated as above and stored at -80°C for five years was tested in a cohort of 131 individuals. No degradation or shift in the equilibrium between ascorbate and dehydroascorbic acid was observed......Lack of post-sampling stability of ascorbate and dehydroascorbic acid and failure to block their in vivo equilibrium have lowered their value as biomarkers of oxidative stress and limited the ability to further investigate their possible role in disease prevention. In the present paper...

Ascorbic acid metabolism in the organism under the lack of oxygen supply to the tissues

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Sergiy Petrov

2017-06-01

Full Text Available The number and ratios of the metabolites of vitamin C - ascorbic, dehydroascorbic and diketogulonic acids were studied under the action of closed space hypoxia, acute blood loss and during sleep – the conditions associated with various oxygen saturation of the organism. It was found that in case of closed space hypoxia, the level of ascorbic and diketogulonic acid decreased with a simultaneous increase in the content of dehydroascorbic acid in the heart and brain. Acute blood loss resulted in decrease in the level of all metabolites of ascorbic acid. During sleep, the level of ascorbic acid metabolites increased. The ratio of vitamin-active metabolites to vitamin-inactive form of ascorbic acid in case of closed space hypoxia and acute blood loss decreased, and during sleep – it did not change significantly.

Ascorbate oxidase is the potential conductor of a symphony of signaling pathways.

Science.gov (United States)

De Tullio, Mario C; Guether, Mike; Balestrini, Raffaella

2013-03-01

The functional role of ascorbate oxidase (AO; EC 1.10.3.3) has never been fully explained so far, due to the difficulties in understanding the presence of an enzyme specifically oxidizing ascorbate with no obvious advantage, and the apparent disadvantage of lowering plant stress resistance as a consequence of ascorbate consumption. Here we suggest a complete change of perspective, by proposing an essential role of AO as a modulator of both ascorbate and oxygen content, with relevant implications related to signaling. By affecting the overall redox state, AO is actually involved in redox regulation in the extracellular matrix. In addition, AO can contribute to creating a hypoxic microenvironment, especially relevant in the maintenance of meristem identity and the establishment of mutualistic plant-microbe interactions. We also hypothesize the possible involvement of AO in the activation of a signaling cascade analogous to the mechanism of prolyl hydroxylases/Hypoxia Inducible Factors in animals.

Cu–hemin metal-organic frameworks with peroxidase-like activity as peroxidase mimics for colorimetric sensing of glucose

Energy Technology Data Exchange (ETDEWEB)

Liu, Fenfen; He, Juan; Zeng, Mulang; Hao, Juan; Guo, Qiaohui; Song, Yonghai; Wang, Li, E-mail: lwanggroup@aliyun.com [Jiangxi Normal University, Key Laboratory of Functional Small Organic Molecule, Ministry of Education, College of Chemistry and Chemical Engineering (China)

2016-05-15

In this work, a facile strategy to synthesize Cu–hemin metal-organic frameworks (MOFs) with peroxidase-like activity was reported. The prepared Cu–hemin MOFs were characterized by various techniques such as scanning electron microscopy, transmission electron microscopy, X-ray powder diffraction, Fourier transform infrared spectroscopy, UV–visible absorbance spectra, and so on. The results showed that the prepared Cu–hemin MOFs looked like a ball-flower with an average diameter of 10 μm and provided a large specific surface area. The Cu–hemin MOFs possessing peroxidase-like activity could be used to catalyze the peroxidase substrate of 3,3,5,5-tetramethylbenzidine in the presence of H{sub 2}O{sub 2}, which was employed to detect H{sub 2}O{sub 2} quantitatively with the linear range from 1.0 μM to 1.0 mM and the detection limit was 0.42 μM. Furthermore, with the additional help of glucose oxidase, a sensitive and selective method to detect glucose was developed by using the Cu–hemin MOFs as catalyst and the linear range was from 10.0 μM to 3.0 mM and the detection limit was 6.9 μM. This work informs researchers of the advantages of MOFs for preparing biomimetic catalysts and extends the functionality of MOFs for biosensor application.Graphical Abstract.

Ascorbate enhances u.v.-mutagenesis in E. coli but inhibits it in Chinese hamster cells

International Nuclear Information System (INIS)

Rossman, T.G.; Klein, C.B.; Naslund, M.

1986-01-01

Ascorbic acid (vitamin C) causes an increase in the mutation frequency of u.v.-irradiated Escherichia coli WP2. The enhancement occurs at all u.v. fluences, and is dependent upon the ascorbate concentration in the medium. A maximum effect (approx. 8- to 13-fold) is seen at 100-150 μg/ml, although some enhancement can be seen even at 10 μg/ml. The comutagenic effect of ascorbate with u.v. in E. coli is dependent upon peptone, a constituent of nutrient broth. The enhancement of u.v.-mutagenesis by ascorbate is absent in strains WP2sub(s) (uvrA) amd WP6 (polA), suggesting that ascorbate affects the repair of pyrimidine dimers. The opposite results are observed for u.v.-mutagenesis in Chinese hamster V79 cells. The presence of ascorbate (50 μg/ml) during u.v. irradiation does not enhance the u.v. effect, but rather decreases it approx. 30%. These results are discussed with regard to differences in the mechanism of u.v.-mutagenesis and DNA repair in bacterial and mammalian cells. (author)

Combined effect of selenium and ascorbic acid on alcohol induced hyperlipidemia in male guinea pigs.

Science.gov (United States)

Asha, G S; Indira, M

2004-02-01

Alcoholics usually suffer from malnutrition and are especially deficient in micronutrients like vitamin C, selenium and Zn. In the present study, combined effects of selenium and ascorbic acid on alcohol-induced hyperlipidemia were studied in guinea pigs. Four groups of male guinea pigs were maintained for 45 days as follows: control (1 mg ascorbate (AA)/100 g body mass/day), ethanol (900 mg ethanol/100 g body mass + 1 mg AA/100 g body mass/day), selenium+ascorbic acid [(25 mg AA + 0.05 mg Se)/100 g body mass/day], ethanol+selenium+ascorbic acid [(25 mg AA + 0.05 mg Se + 900 mg ethanol)/100 g body mass/day]. Co-administration of selenium and ascorbic acid along with alcohol reduced the concentration of all lipids, as also evidenced from the decreased activities of hydroxymethylglutaryl-CoA reductase and enhanced activities of plasma lecithin cholesterol acyl transferase and lipoprotein lipase. Concentrations of bile acids were increased. We conclude that the supplementation of Se and ascorbic acid reduced alcohol induced hyperlipidemia, by decreased synthesis and increased catabolism.

An updated view on horseradish peroxidases: recombinant production and biotechnological applications.

Science.gov (United States)

Krainer, Florian W; Glieder, Anton

2015-02-01

Horseradish peroxidase has been the subject of scientific research for centuries. It has been used exhaustively as reporter enzyme in diagnostics and histochemistry and still plays a major role in these applications. Numerous studies have been conducted on the role of horseradish peroxidase in the plant and its catalytic mechanism. However, little progress has been made in its recombinant production. Until now, commercial preparations of horseradish peroxidase are still isolated from plant roots. These preparations are commonly mixtures of various isoenzymes of which only a small fraction has been described so far. The composition of isoenzymes in these mixed isolates is subjected to uncontrollable environmental conditions. Nowadays, horseradish peroxidase regains interest due to its broad applicability in the fields of medicine, life sciences, and biotechnology in cancer therapy, biosensor systems, bioremediation, and biocatalysis. These medically and commercially relevant applications, the recent discovery of new natural isoenzymes with different biochemical properties, as well as the challenges in recombinant production render this enzyme particularly interesting for future biotechnological solutions. Therefore, we reviewed previous studies as well as current developments with biotechnological emphasis on new applications and the major remaining biotechnological challenge-the efficient recombinant production of horseradish peroxidase enzymes.

Arsenic-induced stress activates sulfur metabolism in different organs of garlic (Allium sativum L.) plants accompanied by a general decline of the NADPH-generating systems in roots.

Science.gov (United States)

Ruíz-Torres, Carmelo; Feriche-Linares, Rafael; Rodríguez-Ruíz, Marta; Palma, José M; Corpas, Francisco J

2017-04-01

Arsenic (As) contamination is a major environmental problem which affects most living organisms from plants to animals. This metalloid poses a health risk for humans through its accumulation in crops and water. Using garlic (Allium sativum L.) plants as model crop exposed to 200μM arsenate, a comparative study among their main organs (roots and shoots) was made. The analysis of arsenic, glutathione (GSH), phytochelatins (PCs) and lipid peroxidation contents with the activities of antioxidant enzymes (catalase, superoxide dismutase, ascorbate-glutathione cycle), and the main components of the NADPH-generating system, including glucose-6-phosphate dehydrogenase (G6PDH), 6-phosphogluconate dehydrogenase (6PGDH), NADP-malic enzyme (NADP-ME) and NADP-isocitrate dehydrogenase (NADP-ICDH) was carried out. Data showed a correlation among arsenic accumulation in the different organs, PCs content and the antioxidative response, with a general decline of the NADPH-generating systems in roots. Overall, our results demonstrate that there are clear connections between arsenic uptake, increase of their As-chelating capacity in roots and a decline of antioxidative enzyme activities (catalase and the ascorbate peroxidase) whose alteration provoked As-induced oxidative stress. Thus, the data suggest that roots act as barrier of arsenic mediated by a prominent sulfur metabolism which is characterized by the biosynthesis of high amount of PCs. Copyright © 2017 Elsevier GmbH. All rights reserved.

Infusion of Hibiscus sabdariffa L. Modulates Oxidative Stress in Patients with Marfan Syndrome

Science.gov (United States)

Soto, María Elena; Zuñiga-Muñoz, Alejandra; Guarner Lans, Verónica; Duran-Hernández, Erendira Janet; Pérez-Torres, Israel

2016-01-01

Marfan syndrome (MFS) is associated with progressive aortic dilatation, endothelial dysfunction, and oxidative stress that contribute to the early acute dissection of the vessel and can end up in rupture of the aorta and sudden death. Many studies have described that the organic acids from Hibiscus sabdariffa Linne (HSL) calyces increase cellular antioxidant capacity and decrease oxidative stress. Here we evaluate if the antioxidant properties of HSL infusion improve oxidative stress in MFS patients. Activities of extra cellular super oxide dismutase (ECSOD), glutathione peroxidase (GPx), glutathione-S-transferase (GST), glutathione reductase (GSSG-R), glutathione (GSH), lipid peroxidation (LPO) index, total antioxidant capacity (TAC), and ascorbic acid were determined in plasma from MFS patients. Values before and after 3 months of the treatment with 2% HSL infusion were compared in control and MFS subjects. After treatment, there was a significant decrease in ECSOD (p = 0.03), EGPx (p = 0.04), GST (p = 0.03), GSH (p = 0.01), and TAC and ascorbic acid (p = 0.02) but GSSG-R activity (p = 0.04) and LPO (p = 0.02) were increased in MFS patients in comparison to patients receiving the HSL treatment and C subjects. Therefore, the infusion of HSL calyces has antioxidant properties that allow an increase in antioxidant capacity of both the enzymatic and nonenzymatic systems, in the plasma of the MSF patients. PMID:27413258

Biological effects of low energy nitrogen ion implantation on Jatropha curcas L. seed germination

Science.gov (United States)

Xu, Gang; Wang, Xiao-teng; Gan, Cai-ling; Fang, Yan-qiong; Zhang, Meng

2012-09-01

To explore the biological effects of nitrogen ion beam implantation on dry Jatropha curcas seed, a beam of N+ with energy of 25 keV was applied to treat the dry seed at six different doses. N+ beam implantation greatly decreased germination rate and seedling survival rate. The doses within the range of 12 × 1016 to 15 × 1016 ions cm-2 severely damaged the seeds: total antioxidant capacity (TAC), germination rate, seedling survival rate, reduced ascorbate acid (HAsA) and reduced glutathione (GSH) contents, and most of the tested antioxidases activity (i.e. catalase (CAT), ascorbate peroxidase (APX) and superoxide dismutase (SOD)) reached their lowest levels. At a dose of 18 × 1016 ion cm-2, biological repair took place: moderate increases were found in TAC, germination rate, seedling survival rate, HAsA and GSH contents, and some antioxidant enzyme activities (i.e. CAT, APX, SOD and GPX). The dose of 18 × 1016 ions cm-2 may be the optimum dose for use in dry J. curcas seed mutation breeding. CAT, HAsA and GSH contributed to the increase of TAC, but CAT was the most important. POD performed its important role as seed was severely damaged. The main role of the HAsA-GSH cycle appeared to be for regeneration of HAsA.

Polyphenol Content, Physicochemical Properties, Enzymatic Activity, Anthocyanin Profiles, and Antioxidant Capacity of Cerasus humilis (Bge. Sok. Genotypes

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Suwen Liu

2018-01-01

Full Text Available Seven varieties of Chinese dwarf cherries were evaluated and compared with respect to their weight, diameter, titratable acidity, total soluble solids, color, polyphenol contents, ascorbic acid levels, anthocyanin profiles, enzymatic activity, and antioxidant capacity. The fruits are rich in phenolic content (339.07–770.30 mg/100 g fresh weight. Nine anthocyanins were obtained from fruits after chromatographic separation and their structures analyzed using HPLC-ESI-MS/MS. Cyanidin-3-glucoside was the major anthocyanin with 50.36–78.39% concentration. Three anthocyanins were reported for the first time in these cherries. They exhibit low polyphenol oxidase and peroxidase activities, but their superoxide dismutase activity is high (572.75–800.17 U/g FW. The highest amounts of soluble solid content (15.67 Brix %, total titratable acid (1.90%, ascorbic acid (18.47 mg/100 g FW, and total anthocyanin (152.66 mg/100 g FW were observed. Three methods (DPPH-scavenging ability, oxygen radical absorbance capacity assay, and cellular antioxidant activity assay were employed to evaluate the antioxidant capacity of the phenolic extracts of these cherries. Number 5 has the highest values of ORAC and CAA of 205.68 μmol TE/g DM and 99.67 μmol QE/100 g FW, respectively.

Effect of calcium and salicylic acid on quality retention in relation to antioxidative enzymes in radish stored under refrigerated conditions.

Science.gov (United States)

Devi, Jomika; Bhatia, Surekha; Alam, M S; Dhillon, Tarsem Singh

2018-03-01

Effect of post harvest treatments with calcium chloride (CaCl 2 ) and salicylic acid (SA) on physiological and biochemical parameters in relation to activities of antioxidative enzymes were investigated in radish. Radish of variety Punjab Safed Mooli 2 was harvested, washed and treated with CaCl 2 (1, 1.5 and 2%) or SA (1, 1.5 and 2 mM). Treated as well as untreated radish were placed in open trays and stored under refrigerated (5 ± 1 °C, 90% RH) conditions for 42 days. Treatment of radish with CaCl 2 and SA slowed down changes in physiological weight, colour, total soluble solids, ascorbic acid, titrable acidity, total phenolics and antioxidant activity. Treated samples exhibited higher enhancement in activities of antioxidant enzymes viz. catalase (CAT), superoxide dismutase (SOD), glutathione reductase (GR), peroxidase (POD), dehydroascorbate reductase (DHAR) and monodehydro-ascorbate reductase (MDHAR) than untreated samples. However SA was found to be more effective in slowing down the metabolic activities of radish as compared to CaCl 2 treatment. Among all the treatments, 1.5 mM SA maintained the quality parameters to greater extent probably by reducing the oxidative stress to larger extent due to highest activities of antioxidative enzymes and can be used to enhance the shelf life of radish during refrigerated storage.

A novel field transplantation technique reveals intra-specific metal-induced oxidative responses in strains of Ectocarpus siliculosus with different pollution histories

International Nuclear Information System (INIS)

Sáez, Claudio A.; González, Alberto; Contreras, Rodrigo A.; Moody, A. John; Moenne, Alejandra; Brown, Murray T.

2015-01-01

A novel field transplantation technique, in which seaweed material is incorporated into dialysis tubing, was used to investigate intra-specific responses to metals in the model brown alga Ectocarpus siliculosus. Metal accumulation in the two strains was similar, with higher concentrations in material deployed to the metal-contaminated site (Ventanas, Chile) than the pristine site (Quintay, Chile). However, the oxidative responses differed. At Ventanas, strain Es147 (from low-polluted site) underwent oxidative damage whereas Es524 (from highly polluted site) was not affected. Concentrations of reduced ascorbate (ASC) and reduced glutathione (GSH) were significantly higher in Es524. Activities of the antioxidant enzymes superoxide dismutase (SOD), ascorbate peroxidase (APX), catalase (CAT), and glutathione reductase (GR) all increased in Es524, whereas only SOD increased in Es147. For the first time, employing a field transplantation technique, we provide unambiguous evidence of inter-population variation of metal-tolerance in brown algae and establish that antioxidant defences are, in part, responsible. - Highlights: • Metal tolerance in Ectocarpus siliculosus populations was studied through in situ experiments. • Metal tolerance in E. siliculosus populations is partly based in antioxidant defences. • In situ experiments using a dialysis tubing device was successful for metal diagnosis. - Field transplantation experimentation provides evidence that differential antioxidant defences, in part, mediate inter-population tolerance to metal pollution in the model brown alga Ectocarpus siliculosus

Pathogen-Induced Changes in the Antioxidant Status of the Apoplast in Barley Leaves

Science.gov (United States)

Vanacker, Hélène; Carver, Tim L.W.; Foyer, Christine H.

1998-01-01

Leaves of two barley (Hordeum vulgare L.) isolines, Alg-R, which has the dominant Mla1 allele conferring hypersensitive race-specific resistance to avirulent races of Blumeria graminis, and Alg-S, which has the recessive mla1 allele for susceptibility to attack, were inoculated with B. graminis f. sp. hordei. Total leaf and apoplastic antioxidants were measured 24 h after inoculation when maximum numbers of attacked cells showed hypersensitive death in Alg-R. Cytoplasmic contamination of the apoplastic extracts, judged by the marker enzyme glucose-6-phosphate dehydrogenase, was very low (less than 2%) even in inoculated plants. Dehydroascorbate, glutathione, superoxide dismutase, catalase, ascorbate peroxidase, glutathione reductase, monodehydroascorbate reductase, and dehydroascorbate reductase were present in the apoplast. Inoculation had no effect on the total foliar ascorbate pool size or the redox state. The glutathione content of Alg-S leaves and apoplast decreased, whereas that of Alg-R leaves and apoplast increased after pathogen attack, but the redox state was unchanged in both cases. Large increases in foliar catalase activity were observed in Alg-S but not in Alg-R leaves. Pathogen-induced increases in the apoplastic antioxidant enzyme activities were observed. We conclude that sustained oxidation does not occur and that differential strategies of antioxidant response in Alg-S and Alg-R may contribute to pathogen sensitivity. PMID:9662553

Infusion of Hibiscus sabdariffa L. Modulates Oxidative Stress in Patients with Marfan Syndrome.

Science.gov (United States)

Soto, María Elena; Zuñiga-Muñoz, Alejandra; Guarner Lans, Verónica; Duran-Hernández, Erendira Janet; Pérez-Torres, Israel

2016-01-01

Marfan syndrome (MFS) is associated with progressive aortic dilatation, endothelial dysfunction, and oxidative stress that contribute to the early acute dissection of the vessel and can end up in rupture of the aorta and sudden death. Many studies have described that the organic acids from Hibiscus sabdariffa Linne (HSL) calyces increase cellular antioxidant capacity and decrease oxidative stress. Here we evaluate if the antioxidant properties of HSL infusion improve oxidative stress in MFS patients. Activities of extra cellular super oxide dismutase (ECSOD), glutathione peroxidase (GPx), glutathione-S-transferase (GST), glutathione reductase (GSSG-R), glutathione (GSH), lipid peroxidation (LPO) index, total antioxidant capacity (TAC), and ascorbic acid were determined in plasma from MFS patients. Values before and after 3 months of the treatment with 2% HSL infusion were compared in control and MFS subjects. After treatment, there was a significant decrease in ECSOD (p = 0.03), EGPx (p = 0.04), GST (p = 0.03), GSH (p = 0.01), and TAC and ascorbic acid (p = 0.02) but GSSG-R activity (p = 0.04) and LPO (p = 0.02) were increased in MFS patients in comparison to patients receiving the HSL treatment and C subjects. Therefore, the infusion of HSL calyces has antioxidant properties that allow an increase in antioxidant capacity of both the enzymatic and nonenzymatic systems, in the plasma of the MSF patients.

[Relationship among glycated compounds, superoxide dismutase activities, and other related analytes in diabetic patients classified by ages].

Science.gov (United States)

Maehata, E; Shimomura, H; Kiyose, H; Hayashi, A; Sakagishi, Y

1991-07-01

Among several glycated compounds (GC) which are based on Maillard reaction, glycated hemoglobin (HbA1c) and fructosamine (FRA) have been utilized widely as a markers of diabetes. Recently, glycated albumin (GA) has been pointed out as a new indicator. For the determination of GA, spectrophotometry combined with an affinity column method has been mainly used, however the procedure is complicated. Recently a two-column HPLC method (ion-exchange column and affinity column) has been developed by Shima. We have evaluated a GA analyzer GAA-2000 based on Shima's method. After a series of fundamental and performance evaluation studies, the GAA-2000 was found to be appropriate for our study. Reference values obtained from this equipment were 10.56-16.87%. Correlation coefficients based on GA using diabetic and diabetic nephropathy patient specimens (n = 87) were: FRA (r = 0.944) greater than HbA1c (r = 0.842) greater than Glucose (r = 0.510) Superoxide dismutase (SOD) and lipid peroxidase (LPO) with are produced in relation to active oxygen did not show a good correlation. Although we tried classify the patients according to juvenile (20-39), middle (40-64) and senile (greater than 65) the method of Asada et al., we could not find any distinct tendencies.

Screening of postharvest agricultural wastes as alternative sources of peroxidases: characterization and kinetics of a novel peroxidase from lentil ( Lens culinaris L.) stubble.

Science.gov (United States)

Hidalgo-Cuadrado, Nazaret; Pérez-Galende, Patricia; Manzano, Teresa; De Maria, Cándido Garcia; Shnyrov, Valery L; Roig, Manuel G

2012-05-16

Aqueous crude extracts of a series of plant wastes (agricultural, wild plants, residues from sports activities (grass), ornamental residues (gardens)) from 17 different plant species representative of the typical biodiversity of the Iberian peninsula were investigated as new sources of peroxidases (EC 1.11.1.7). Of these, lentil (Lens culinaris L.) stubble crude extract was seen to provide one of the highest specific peroxidase activities, catalyzing the oxidation of guaiacol in the presence of hydrogen peroxide to tetraguaiacol, and was used for further studies. For the optimum extraction conditions found, the peroxidase activity in this crude extract (110 U mL(-1)) did not vary for at least 15 months when stored at 4 °C (k(inact) = 0.146 year(-1), t(1/2 inact) = 4.75 year), whereas, for comparative purposes, the peroxidase activity (60 U mL(-1)) of horseradish (Armoracia rusticana L.) root crude extract, obtained and stored under the same conditions, showed much faster inactivation kinetics (k(inact) = 2.2 × 10(-3) day(-1), t(1/2 inact) = 315 days). Using guaiacol as an H donor and a universal buffer (see above), all crude extract samples exhibited the highest peroxidase activity in the pH range between 4 and 7. Once semipurified by passing the crude extract through hydrophobic chromatography on phenyl-Sepharose CL-4B, the novel peroxidase (LSP) was characterized as having a purity number (RZ) of 2.5 and three SDS-PAGE electrophoretic bands corresponding to molecular masses of 52, 35, and 18 kDa. The steady-state kinetic study carried out on the H(2)O(2)-mediated oxidation of guaiacol by the catalytic action of this partially purified peroxidase pointed to apparent Michaelian kinetic behavior (K(m)(appH(2)O(2)) = 1.87 mM; V(max)(appH(2)O(2)) = 6.4 mM min(-1); K(m)(app guaicol) = 32 mM; V(max)(app guaicol) = 9.1 mM min(-1)), compatible with the two-substrate ping-pong mechanism generally accepted for peroxidases. Finally, after the effectiveness of the crude

The Use of Ascorbic Acid as a Food Additive: Technical-Legal Issues

Science.gov (United States)

Varvara, Michele; Bozzo, Giancarlo; Celano, Giuseppe; Disanto, Chiara; Pagliarone, Cosimo Nicola

2016-01-01

Ascorbic acid (C6H8O6) is an organic compound belonging to the family of monosaccharide. It is highly soluble in water, and is often called one of the secrets of the Mediterranean diet. Its use is widespread in the food industry is also important, having always been exploited for its antioxidant and stabilising ability. Many indeed are the additive formulations that take advantage of these properties. The purpose of this paper is to explain the characteristics that make ascorbic acid an important food additive and to emphasise the technical and legal issues related to its use in food productions. In particular, in the course of this employment, laws and scientific studies have been applied to the resolution of a lawsuit, having as its object the use of ascorbic acid in preparations of ground beef sold at a butcher shop. The views expressed in court by the technical consultant have led to the acquittal of the accused, in the light of the demonstrated and proven non-toxicity of the molecule and the use of a mixture of additives for the production of sausage. The European and national legislations, supported by numerous scientific studies, define the possible use of ascorbic acid according to the principle of quantum satis, and it can be used in foods for children. Our work aims to represent further evidence of the safety of use of ascorbic acid as a food additive, and – as confirmed by the legal decision reported – it wants to bring out the prospects for use of ascorbic acid for technological purposes even by registered establishments. PMID:27800425

The effect of irradiation on biological defense system of experimental rabbits

International Nuclear Information System (INIS)

Urata, Yoshishige; Goto, Shinzi; Kondo, Takahito; Shimasaki, Tatsuya; Okumura, Yutaka

1992-01-01

Radiation effects on antioxidant factors as glutathione, glutathione peroxidase, catalase, glutathione S-transferase, γ-gluthamine cysteine synthetase, Cu, Zn-superoxide dismutase and Mn-superoxide dismutase are measured in liver, kidney and genitals of rabbits with single irradiation of 50 Gy X-ray. (J.P.N.)

A method for the determination of ascorbic acid using the iron(II)-pyridine-dimethylglyoxime complex

International Nuclear Information System (INIS)

Arya, S. P.; Mahajan, M.

1998-01-01

A simple and rapid spectrophotometric method for the determination of ascorbic acid is proposed. Ascorbic acid reduces iron (III) to iron (II) which forms a red colored complex with dimethylglyoxime in the presence of pyridine. The absorbance of the resulting solution is measured at 514 nm and a linear relationship between absorbance and concentration of ascorbic acid is observed up to 14 μg ml -1 . Studies on the interference of substances usually associated with ascorbic acid have been carried out and the applicability of the method has been tested by analysing pharmaceutical preparations of vitamin C [it

DYNAMICS OF LEAF PEROXIDASE ACTIVITY DURING ONTOGENY OF HEMP PLANTS, IN RELATION TO SEXUAL PHENOTYPE

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Elena Truta

2005-08-01

Full Text Available During vegetation of female and male hemp plants (Cannabis sativa L., five quantitative determinations of peroxidase activities were made (40 days, 55 days, 70 days, 85 days, 105 days. Peroxidase activity presented some differences in hemp plants, between females and males, during their vegetation cycle. In female plants, before anthesis were registered peaks of peroxidase activities. The blossoming of male plants was coincident with the increase of catalitic action of peroxidase. Generally, the male plants displayed greater levels of peroxidasic activity.

Dietary taurine alters ascorbic acid metabolism in rats fed diets containing polychlorinated biphenyls.

Science.gov (United States)

Mochizuki, H; Oda, H; Yokogoshi, H

2000-04-01

The effect of dietary taurine on ascorbic acid metabolism and hepatic drug-metabolizing enzymes was investigated in rats fed diets containing polychlorinated biphenyls (PCB) to determine whether taurine has an adaptive and protective function in xenobiotic-treated animals. Young male Wistar rats (60 g) were fed diets containing 0 or 0.2 g/kg diet PCB with or without 30 g/kg diet of taurine for 14 d. The rats fed the PCB-containing diets had greater liver weight, higher ascorbic acid concentrations in the liver and spleen and greater hepatic cytochrome P-450 contents than control rats that were not treated with PCB (P ascorbic acid excretion was enhanced, and serum cholesterol concentration (especially HDL-cholesterol) was significantly elevated compared with those in control rats. Dietary taurine significantly potentiated the increases in the urinary excretion of ascorbic acid and the rise in the levels of cytochrome P-450 which were caused by PCB treatment. On the other hand, the supplementation of taurine to control diet did not alter these variables. Taurine may enhance the hepatic drug-metabolizing systems, leading to the stimulation of the ascorbic acid metabolism in rats fed diets containing PCB.

Pyrophosphate levels strongly influence ascorbate and starch content in tomato fruit

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Sonia eOsorio

2013-08-01

Full Text Available Ascorbate (vitamin C deficiency leads to low immunity, scurvy, and other human diseases and is therefore a global health problem. Given that plants are major ascorbate sources for humans, biofortification of this vitamin in our foodstuffs is of considerable importance. Ascorbate is synthetized by a number of alternative pathways: (i from the glycolytic intermediates D-glucose-6P (the key intermediates are GDP-D-mannose and L-galactose, (ii from the breakdown of the cell wall polymer pectin which uses the methyl ester of D-galacturonic acid as precursor and (iii from myo-inositol as precursor via myo-inositol oxygenase. We report here the engineering of fruit-specific overexpression of a bacterial pyrophosphatase, which hydrolyzes the inorganic pyrophosphate (PPi to orthophosphate (Pi. This strategy resulted in increased vitamin C levels up to 2.5 fold in ripe fruit as well as increasing in the major sugars, sucrose and glucose, yet decreasing the level of starch. When considered together, these finding indicate an intimate linkage between ascorbate and sugar biosynthesis in plants. Moreover, the combined data reveal the importance of PPi metabolism in tomato fruit metabolism and development.

Cooxidation of styrene by horseradish peroxidase and phenols. A biochemical model for protein-mediated cooxidation

International Nuclear Information System (INIS)

Ortiz de Montellano, P.R.; Grab, L.A.

1987-01-01

Styrene is oxidized to styrene oxide and benzaldehyde when incubated with horseradish peroxidase, H 2 O 2 , and 4-methylphenol. Styrene oxide is not formed in the absence of any of these reaction components or of molecular oxygen. The coupling products 2-(4-methylphenoxy)-1-phenylethane, 2-(4-methylphenoxy)-1-phenylethan-1-ol, and 2-(4-methylphenoxy)-2-phenylethan-1-ol are not formed, but the ortho-linked dimer of 4-methylphenol is a major product. The epoxide oxygen is labeled in the presence of 18 O 2 but not H 2 18 O 2 . Styrene oxide formation is not inhibited by mannitol or superoxide dismutase. The stereochemistry of trans-[1- 2 H]styrene is partially scrambled in the epoxide product. EPR signals attributable to the 2,4-dihydroxyl-5-methylphenoxy radical, a product of the oxidation of 4-methylcatechol, are observed if Zn 2+ is added to stabilize the radical. This radical is only detected in the presence of styrene. The results imply that styrene is epoxidized by the hydroperoxy radical generated by addition of molecular oxygen to the 4-methylphenoxy radical. The epoxidation mimics the chemistry proposed to occur in the protein-mediated cooxidation of styrene by hemoglobin and myoglobin

Purification and characterization of an intracellular catalase-peroxidase from Penicillium simplicissimum

NARCIS (Netherlands)

Fraaije, Marco W.; Roubroeks, Hanno P.; Hagen, Wilfred R.; Berkel, Willem J.H. van

1996-01-01

The first dimeric catalase-peroxidase of eucaryotic origin, an intracellular hydroperoxidase from Penicillium simplicissimum which exhibited both catalase and peroxidase activities, has been isolated. The enzyme has an apparent molecular mass of about 170 kDa and is composed of two identical

Extraction of Erythrocyte Enzymes for the Preparation of Polyhemoglobin-catalase-superoxide Dismutase

OpenAIRE

Gu, Jingsong; Chang, Thomas Ming Swi

2009-01-01

In sustained severe ischemia, reperfusion with oxygen carriers may result in ischemia-reperfusion injuries because of the release of damaging oxygen radicals. A nanobiotechnology-based polyhemogloin-calatase-superoxide dismutase can prevent this because the oxygen carrier, polyhemoglobin, is linked to antioxidant enzymes, catalase and superoxide dismutase. However, these antioxidant enzymes come from nonhuman sources and recombinant human enzymes are expensive. This paper describes our study ...

Ascorbic acid effects on in vitro maturation of mouse oocyte with or ...

African Journals Online (AJOL)

Ascorbic acid has long been associated with fertility. This study was designed to determine the effects of ascorbic acid on in vitro maturation of mouse oocyte with or without cumulus cells. In this study, 508 denuded oocytes (DOs) and 527 cumulus–oocyte complexes (COCs) from mice stimulated with pregnant mare's serum ...

Ascorbic Acid Alleviates Water Stress in Young Peach Trees and Improves Their Performance after Rewatering.

Science.gov (United States)

Penella, Consuelo; Calatayud, Ángeles; Melgar, Juan C

2017-01-01

Exogenous application of biochemicals has been found to improve water stress tolerance in herbaceous crops but there are limited studies on deciduous fruit trees. The goal of this research was to study if ascorbic acid applications could improve physiological mechanisms associated with water stress tolerance in young fruit trees. Ascorbic acid was foliarly applied at a concentration of 250 ppm to water-stressed and well-watered peach trees (control) of two cultivars ('Scarletprince' and 'CaroTiger'). Trees received either one or two applications, and 1 week after the second application all trees were rewatered to field capacity. Upon rewatering, CO 2 assimilation and stomatal conductance of water-stressed 'Scarletprince' trees sprayed with ascorbic acid (one or two applications) were similar to those of well-irrigated trees, but water-stressed trees that had not received ascorbic acid did not recover photosynthetical functions. Also, water status in sprayed water-stressed 'Scarletprince' trees was improved to values similar to control trees. On the other hand, water-stressed 'CaroTiger' trees needed two applications of ascorbic acid to reach values of CO 2 assimilation similar to control trees but these applications did not improve their water status. In general terms, different response mechanisms to cope with water stress in presence of ascorbic acid were found in each cultivar, with 'Scarletprince' trees preferentially using proline as compatible solute and 'CaroTiger' trees relying on stomatal regulation. The application of ascorbic acid reduced cell membrane damage and increased catalase activity in water-stressed trees of both cultivars. These results suggest that foliar applications of ascorbic acid could be used as a management practice for improving water stress tolerance of young trees under suboptimal water regimes.

Guaiacol peroxidase zymography for the undergraduate laboratory.

Science.gov (United States)

Wilkesman, Jeff; Castro, Diana; Contreras, Lellys M; Kurz, Liliana

2014-01-01

This laboratory exercise presents a novel way to introduce undergraduate students to the specific detection of enzymatic activity by electrophoresis. First, students prepare a crude peroxidase extract and then analyze the homogenate via electrophoresis. Zymography, that is, a SDS-PAGE method to detect enzyme activity, is used to specifically detect peroxidase activity and furthermore, to analyze the total protein profile. After the assay, students may estimate the apparent molecular mass of the enzyme and discuss its structure. After the 4-h experiment, students gain knowledge concerning biological sample preparation, gel preparation, electrophoresis, and the importance of specific staining procedures for the detection of enzymatic activity. Copyright © 2014 The International Union of Biochemistry and Molecular Biology.

The browning kinetics of the non-enzymatic browning reaction in L-ascorbic acid/basic amino acid systems

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Ai-Nong YU

Full Text Available Abstract Under the conditions of weak basis and the reaction temperature range of 110-150 °C, lysine, arginine and histidine were reacted with L-ascorbic acid at equal amount for 30-150 min, respectively and the formation of browning products was monitored with UV–vis spectrometry. The kinetic characteristics of their non-enzymatic browning reaction were investigated. The study results indicated that the non-enzymatic browning reaction of these three amino acids with L-ascorbic acid to form browning products was zero-order reaction. The apparent activation energies for the formation of browning products from L-ascorbic acid/lysine, L-ascorbic acid/arginine and L-ascorbic acid/histidine systems were 54.94, 50.08 and 35.31kJ/mol. The activation energy data indicated the degree of effects of reaction temperature on non-enzymatic browning reaction. Within the temperature range of 110-150 °C, the reaction rate of L-ascorbic acid/lysine system was the fastest one, followed by that of the L-ascorbic acid/arginine system. The reaction rate of L-ascorbic acid/histidine system was the slowest one. Based on the observed kinetic data, the formation mechanisms of browning products were proposed.

Effects of Pre-Converted Nitrite from Red Beet and Ascorbic Acid on Quality Characteristics in Meat Emulsions

Science.gov (United States)

Kim, Hyun-Wook; Hwang, Ko-Eun

2017-01-01

We investigated the effects of fermented red beet extract and ascorbic acid on color development in meat emulsions. The pH of meat emulsions containing red beet extract decreased with an increase in the amount of extract added. The redness of the treated meat emulsions was higher than that of the control with no added nitrite or fermented red beet extract (pmeat emulsions treated with fermented red beet extract only was lower than in that treated with both fermented red beet extract and ascorbic acid (pmeat emulsions treated with fermented red beet extract were higher than in that treated with both fermented red beet extract and ascorbic acid (pmeat emulsions tested. Treatment T2, containing nitrite and ascorbic acid, had the highest overall acceptability score (pnitrite from red beet extract and 0.05% ascorbic acid (p>0.05). The residual nitrite content of the meat emulsions treated with ascorbic acid was lower than in those treated without ascorbic acid (pnitrite for the stability of color development in meat emulsions. PMID:28515652

Ascorbic acid levels in human tears after photorefractive keratectomy, transepithelial photorefractive keratectomy, and laser in situ keratomileusis.

Science.gov (United States)

Bilgihan, A; Bilgihan, K; Toklu, Y; Konuk, O; Yis, O; Hasanreisoğlu, B

2001-04-01

To investigate the level of ascorbic acid in human tear fluid after photorefractive keratectomy (PRK), transepithelial PRK, and laser in situ keratomileusis (LASIK). Departments of Ophthalmology and Biochemistry, School of Medicine, Gazi University, Ankara, Turkey. Twenty patients (7 women and 13 men) were included in this study. Traditional PRK with epithelial scraping by a blunt spatula followed by surface ablation (7 eyes), transepithelial PRK (7 eyes), or LASIK (6 eyes) was performed. Tears were collected preoperatively and 1 and 5 days postoperatively. Ascorbic acid levels were measured using 2-4 dinitrophenylhydrazine. Ascorbic acid levels in the tear fluid were decreased significantly 1 day after PRK, transepithelial PRK, and LASIK (P <.05). On the fifth day, the ascorbic acid levels were significantly lower than preoperatively in all groups. After PRK, transepithelial PRK, and LASIK, the ascorbic acid levels of the tear fluid decreased significantly. Because ascorbic acid is the major scavenger of superoxide radicals in tears, topical ascorbic acid therapy may help eliminate the harmful effect of free radicals from excimer laser surgery.

Alterations in antioxidant metabolism in coffee leaves infected by Cercospora coffeicola

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Camila Cristina Lage de Andrade

2016-01-01

Full Text Available ABSTRACT: Brown eye spot (BE caused by Cercospora coffeicola is the main disease of coffee crop. A variation in symptoms of BE has been reported in the field, raising suspicion of occurrence of new species. However, information about coffee- C. coffeicola interaction is still limited. This research aimed to determine the difference between antioxidant metabolism of coffee plants cultivar Mundo Novo inoculated with a strain isolated from a common BE lesion (CML 2984 and a strain isolated from a black BE lesion (CML 2985. The enzyme activity of peroxidase (POX, catalase (CAT, superoxide dismutase (SOD, ascorbate peroxidase (APX and phenylalanine ammonia lyase (PAL were determined. Activities of POX, APX, and PAL increased in plants inoculated with both strains compared to non-inoculated plants at 12 and 24 hours post inoculation (hpi. CAT activity increased in inoculated plants with black BE strain at 24 hpi and both strains at 48 hpi. The SOD activity only increased in inoculated plants with both strains at 48 hpi. These results show that an elevated antioxidant response was observed when the plants were challenged with both strains of C. coffeicola. Both strains produced lesions of the common type, suggesting that other factors lead to the development of black BE lesion type under field conditions and further investigation is needed.

Seed priming with KNO3 mediates biochemical processes to inhibit lead toxicity in maize (Zea mays L.).

Science.gov (United States)

Nawaz, Fahim; Naeem, Muhammad; Akram, Asim; Ashraf, Muhammad Y; Ahmad, Khawaja S; Zulfiqar, Bilal; Sardar, Hasan; Shabbir, Rana N; Majeed, Sadia; Shehzad, Muhammad A; Anwar, Irfan

2017-11-01

Accumulation of lead (Pb) in agricultural soils has become a major factor for reduced crop yields and poses serious threats to humans consuming agricultural products. The present study investigated the effects of KNO 3 seed priming (0 and 0.5% KNO 3 ) on growth of maize (Zea mays L.) seedlings exposed to Pb toxicity (0, 1300 and 2550 mg kg -1 Pb). Pb exposure markedly reduced the growth of maize seedlings and resulted in higher Pb accumulation in roots than shoots. Pretreatment of seeds with KNO 3 significantly improved the germination percentage and increased physiological indices. A stimulating effect of KNO 3 seed priming was also observed on pigments (chlorophyll a, b, total chlorophyll and carotenoid contents) of Pb-stressed plants. Low translocation of Pb from roots to shoots caused an increased accumulation of total free amino acids and higher activities of catalase, peroxidase, superoxide dismutase and ascorbate peroxidase in roots as compared to shoot, which were further enhanced by exogenous KNO 3 supply to prevent Pb toxicity. Maize accumulates more Pb in roots than shoot at early growth stages. Priming of seeds with KNO 3 prevents Pb toxicity, which may be exploited to improve seedling establishment in crop species grown under Pb contaminated soils. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Effects of UV-B irradiation on isoforms of antioxidant enzymes and their activities in red alga Grateloupia filicina (Rhodophyta)

Science.gov (United States)

Zhao, Jiqiang; Li, Lixia

2014-11-01

Macroalgae in a littoral zone are inevitably exposed to UV-B irradiance. We analyzed the effects of UV-B on isoenzyme patterns and activities of superoxide dismutase (SOD), peroxidase (POX), catalase (CAT), and ascorbate peroxidase (APX) of red algae Grateloupia filicina (Lamour.) C. Agardh. The activities of SOD, CAT, and APX changed in response to UV-B in a time- and dose-dependent manner. POX activity increased significantly under all three UV-B treatments. The enzymatic assay showed three distinct bands of SODI (Mn-SOD), SODII (Fe-SOD), and SODIII (CuZn-SOD) under a low (Luv) and medium (Muv) dose of UV-B irradiation, while SODI and SODIII activities decreased significantly when exposed to a high dose of UV-B irradiation (Huv). The activity of POX isoenzymes increased significantly after exposure to UV-B, which is consistent with the total activity. In addition, a clear decrease in activity of CATIV was detected in response to all the three doses of UV treatments. Some bands of APX isoenzyme were also clearly influenced by UV-B irradiation. Correspondingly, the daily growth rate declined under all the three exposure doses, and was especially significant under Muv and Huv treatments. These data suggest that, although the protection mechanisms of antioxidant defense system are partly inducible by UV-B to prevent the damage, G. filicina has incomplete tolerance to higher UV-B irradiation stress.

Green Synthesized Zinc Oxide (ZnO) Nanoparticles Induce Oxidative Stress and DNA Damage in Lathyrus sativus L. Root Bioassay System.

Science.gov (United States)

Panda, Kamal K; Golari, Dambaru; Venugopal, A; Achary, V Mohan M; Phaomei, Ganngam; Parinandi, Narasimham L; Sahu, Hrushi K; Panda, Brahma B

2017-05-18

Zinc oxide nanoparticles (ZnONP-GS) were synthesised from the precursor zinc acetate (Zn(CH₃COO)₂) through the green route using the milky latex from milk weed ( Calotropis gigantea L. R. Br) by alkaline precipitation. Formation of the ZnONP-GS was monitored by UV-visible spectroscopy followed by characterization and confirmation by energy-dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), and X-ray diffraction (XRD). Both the ZnONP-GS and the commercially available ZnONP-S (Sigma-Aldrich) and cationic Zn 2+ from Zn(CH₃COO)₂ were tested in a dose range of 0-100 mg·L -1 for their potency (i) to induce oxidative stress as measured by the generation reactive oxygen species (ROS: O₂ •- , H₂O₂ and • OH), cell death, and lipid peroxidation; (ii) to modulate the activities of antioxidant enzymes: catalase (CAT), superoxide dismutase (SOD), guaiacol peroxidase (GPX), and ascorbate peroxidase (APX); and (iii) to cause DNA damage as determined by Comet assay in Lathyrus sativus L. root bioassay system. Antioxidants such as Tiron and dimethylthiourea significantly attenuated the ZnONP-induced oxidative and DNA damage, suggesting the involvement of ROS therein. Our study demonstrated that both ZnONP-GS and ZnONP-S induced oxidative stress and DNA damage to a similar extent but were significantly less potent than Zn 2+ alone.

COMPARISON OF METHODS FOR ALKALINE PHOSPHATASE AND PEROXIDASE DETECTION IN MILK

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felipe Nael Seixas

2014-02-01

Full Text Available This study evaluated the performance of strips for colorimetric detection of alkaline phosphatase and peroxidase in milk, comparing them with a kit of reagents for alkaline phosphatase and the official methodology for peroxidase. The samples were analyzed at the Laboratory Inspection of Products of Animal Origin, State University of Londrina. For the comparison tests for the detection of alkaline phosphatase four treatments were made by adding different percentages of raw milk (1%, 2%, 5% and 10% in the pasteurized milk, plus two control treatments. Thirty-eight samples triplicate for each treatment were analyzed. To compare the performance of tests for peroxidase 80 pasteurized milk samples were evaluated simultaneously by official methodology and by colorimetric strips. The performance of the alkaline phosphatase were different for the treatments with 1% and 2% of raw milk which had all the strips change color as the reagent kit showed the presence of phosphatase in just 2.63% and 5.26% the cases, respectively for each treatment. The colorimetric strips for alkaline phosphatase are more sensitive for the identification of small quantities compared to the reagent kit. The performance of tests for peroxidase showed no difference. The strips for the detection of peroxidase or alkaline phosphatase were effective and can replace traditional methods.

Study of Ascorbic Acid as Iron(III Reducing Agent for Spectrophotometric Iron Speciation

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Antesar Elmagirbi

2012-10-01

Full Text Available The study of ascorbic acid as a reducing agent for iron(III has been investigated in order to obtain an alternative carcinogenic reducing agent, hydroxylamine, used in spectrophotometric standard method based on the formation of a red-orange complex of Fe(II-o-phenanthroline. The study was optimised with regards to ascorbic acid concentration as well as pH solution. The results showed that ascorbic acid showed maximum capacity as reducing agent of iron(III under concentration of 4.46.10-4 M and pH solution of 1-4.Under these conditions, ascorbic acid reduced iron(III proportionally and performed similarly to that of hydroxylamine.  The method gave result to linear calibration over the range of 0.2-2 mg/L withhigh accuracy of 97 % and relative standard deviation of less than 2 %. This method was successfully applied to assay iron speciation in water samples.

Effects of ascorbic acid and antioxidants on color, lipid oxidation and volatiles of irradiated ground beef

International Nuclear Information System (INIS)

Ahn, D.U.; Nam, K.C.

2004-01-01

Beef loins with 3 different aging times after slaughter were ground, added with none, 0.1% ascorbic acid, 0.01% sesamol+0.01% α-tocopherol, or 0.1% ascorbic acid+0.01% sesamol+0.01% tocopherol. The meats were packaged in oxygen-permeable bags, irradiated at 2.5 kGy, and color, oxidation-reduction potential (ORP), lipid oxidation and volatile profiles were determined. Irradiation decreased the redness of ground beef, and visible color of beef changed from a bright red to a green/brown depending on the age of meat. Addition of ascorbic acid prevented color changes in irradiated beef, and the effect of ascorbic acid became greater as the age of meat or storage time after irradiation increased. The ground beef added with ascorbic acid had lower ORP than control, and the low ORP of meat helped maintaining the heme pigments in reduced form. During aerobic storage, S-volatiles disappeared while volatile aldehydes significantly increased in irradiated beef. Addition of ascorbic acid at 0.1% or sesamol+α-tocopherol at each 0.01% level to ground beef prior to irradiation were effective in reducing lipid oxidation and S-volatiles. As storage time increased, however, the antioxidant effect of sesamol+tocopherol in irradiated ground beef was superior to that of ascorbic acid

Effects of ascorbic acid and antioxidants on color, lipid oxidation and volatiles of irradiated ground beef

Energy Technology Data Exchange (ETDEWEB)

Ahn, D.U. E-mail: duahn@iastate.edu; Nam, K.C

2004-10-01

Beef loins with 3 different aging times after slaughter were ground, added with none, 0.1% ascorbic acid, 0.01% sesamol+0.01% {alpha}-tocopherol, or 0.1% ascorbic acid+0.01% sesamol+0.01% tocopherol. The meats were packaged in oxygen-permeable bags, irradiated at 2.5 kGy, and color, oxidation-reduction potential (ORP), lipid oxidation and volatile profiles were determined. Irradiation decreased the redness of ground beef, and visible color of beef changed from a bright red to a green/brown depending on the age of meat. Addition of ascorbic acid prevented color changes in irradiated beef, and the effect of ascorbic acid became greater as the age of meat or storage time after irradiation increased. The ground beef added with ascorbic acid had lower ORP than control, and the low ORP of meat helped maintaining the heme pigments in reduced form. During aerobic storage, S-volatiles disappeared while volatile aldehydes significantly increased in irradiated beef. Addition of ascorbic acid at 0.1% or sesamol+{alpha}-tocopherol at each 0.01% level to ground beef prior to irradiation were effective in reducing lipid oxidation and S-volatiles. As storage time increased, however, the antioxidant effect of sesamol+tocopherol in irradiated ground beef was superior to that of ascorbic acid.

Ascorbic acid prevents vascular dysfunction induced by oral glucose load in healthy subjects.

Science.gov (United States)

De Marchi, Sergio; Prior, Manlio; Rigoni, Anna; Zecchetto, Sara; Rulfo, Fanny; Arosio, Enrico

2012-01-01

To examine the effects of oral glucose load on forearm circulatory regulation before and after ascorbic acid administration in healthy subjects. Microcirculation study with laser Doppler was performed at the hand in basal conditions, after ischemia and after acetylcholine and nitroprusside; strain gauge plethysmography was performed at basal and after ischemia. The tests were repeated in the same sequence 2 hour after oral administration of glucose (75 g). The subjects were randomised for administration of ascorbic acid (1 g bid) or placebo (sodium bicarbonate 1 g bid) for 10 days. After that, the tests were repeated before and after a new oral glucose load. Blood pressure and heart rate were monitored. Macrocirculatory flux, pressure values and heart rate were unvaried throughout the study. The glucose load caused a reduction in the hyperemic peak flow with laser Doppler and plethysmography; it reduced flux recovery time and hyperemic curve area after ischemia; acetylcholine elicited a minor increase in flux with laser Doppler. The response to nitroprusside was unvaried after glucose load as compared to basal conditions. Treatment with ascorbic acid prevented the decrease in hyperemia after glucose, detected with laser Doppler and plethysmography. Ascorbic acid prevented the decreased response to acetylcholine after glucose, the response to nitroprusside was unaffected by ascorbic acid. Results after placebo were unvaried. Oral glucose load impairs endothelium dependent dilation and hyperaemia at microcirculation, probably via oxidative stress; ascorbic acid can prevent it. Copyright © 2011 European Federation of Internal Medicine. Published by Elsevier B.V. All rights reserved.

Heterologous Expression of Peroxidases : Chapter 12

NARCIS (Netherlands)

Christien Lokman; S. de Weert

2010-01-01

This monograph describes many applications of peroxidase-based biocatalysis in the biotechnology industry. The need for such a book emerges from the considerable amount of new data regarding the phylogeny, reaction mechanisms, thermodynamic characterization and structural features of fungal and

Intramolecular electron transfer in ascorbate oxidase is enhanced in the presence of oxygen

DEFF Research Database (Denmark)

Farver, O; Wherland, S; Pecht, I

1994-01-01

Intramolecular electron transfer from the type 1 copper center to the type 3 copper(II) pair is induced in the multi-copper enzyme, ascorbate oxidase, following pulse radiolytic reduction of the type 1 Cu(II) ion. In the presence of a slight excess of dioxygen over ascorbate oxidase, interaction...... between the trinuclear copper center and O2 is observed even with singly reduced ascorbate oxidase molecules. Under these conditions, the rate constant for intramolecular electron transfer from type 1 Cu(I) to type 3 Cu(II) increases 5-fold to 1100 +/- 300 s-1 (20 degrees C, pH 5.8) as compared...

Methemoglobinemia and ascorbate deficiency in hemoglobin E β thalassemia: metabolic and clinical implications

Science.gov (United States)

Allen, Angela; Fisher, Christopher; Premawardhena, Anuja; Bandara, Dayananda; Perera, Ashok; Allen, Stephen; St Pierre, Timothy; Olivieri, Nancy

2012-01-01

During investigations of the phenotypic diversity of hemoglobin (Hb) E β thalassemia, a patient was encountered with persistently high levels of methemoglobin associated with a left-shift in the oxygen dissociation curve, profound ascorbate deficiency, and clinical features of scurvy; these abnormalities were corrected by treatment with vitamin C. Studies of erythropoietin production before and after treatment suggested that, as in an ascorbate-deficient murine model, the human hypoxia induction factor pathway is not totally dependent on ascorbate levels. A follow-up study of 45 patients with HbE β thalassemia showed that methemoglobin levels were significantly increased and that there was also a significant reduction in plasma ascorbate levels. Haptoglobin levels were significantly reduced, and the high frequency of the 2.2 haptoglobin genotype may place an additional pressure on ascorbate as a free-radical scavenger in this population. There was, in addition, a highly significant correlation between methemoglobin levels, splenectomy, and factors that modify the degree of globin-chain imbalance. Because methemoglobin levels are modified by several mechanisms and may play a role in both adaptation to anemia and vascular damage, there is a strong case for its further study in other forms of thalassemia and sickle-cell anemia, particularly when splenic function is defective. PMID:22885163

Arsenic-induced toxicity and the protective role of ascorbic acid in mouse testis

International Nuclear Information System (INIS)

Chang, Soo Im; Jin, Bohwan; Youn, Pilju; Park, Changbo; Park, Jung-Duck; Ryu, Doug-Young

2007-01-01

Oxidative stress has been suggested to be a major cause of male reproductive failure. Here, we investigated whether arsenic, which impairs male reproductive functions in rodent models, acts by inducing oxidative stress. Male 8-week-old ICR mice were given drinking water containing 20 or 40 mg/l sodium arsenite with or without 0.75 or 1.5 g/l of the antioxidant ascorbic acid for 5 weeks. The arsenic-treated mice showed decreased epididymidal sperm counts and testicular weights compared to untreated mice. These effects were reversed in mice that were co-treated with ascorbic acid. Similarly, arsenic treatment lowered the activities of testicular 3β-hydroxysteroid dehydrogenase (HSD) and 17β-HSD, which play important roles in steroidogenesis, and this was reversed by co-treatment with ascorbic acid. The testicles of arsenic-treated mice had decreased glutathione (GSH) levels (which correlate inversely with the degree of cellular oxidative stress) and elevated levels of protein carbonyl (a marker of oxidative damage to tissue proteins). Ascorbic acid co-treatment reversed both of these effects. Thus, ascorbic acid blocks both the adverse effects of arsenic on male reproductive functions and the arsenic-induced testicular oxidative changes. These observations support the notion that arsenic impairs male reproductive function by inducing oxidative stress

Ascorbic acid reduced mutagenicity at the HPRT locus in CHO cells against thermal neutron radiation

International Nuclear Information System (INIS)

Kinashi, Yuko; Sakurai, Yoshinori; Masunaga, Shinichiro; Suzuki, Minoru; Nagata, Kenji; Ono, Koji

2004-01-01

We investigated the biological effects of the long-lived radicals induced following neutron irradiation. It has been reported that radiation-induced long-lived radicals were scavenged by post-irradiation treatment of ascorbic acid (Koyama, 1998). We studied the effects of ascorbic acid acting as a long-lived radical scavenger on cell killing and mutagenicity in Chinese hamster ovary cells against thermal neutrons produced at the Kyoto University Research reactor. Ascorbic acid was added to cells 30 min after neutron irradiation and removed 150 min after irradiation. The biological end point of cell survival was measured by colony formation assay. The mutagenicity was measured by the mutant frequency in the HPRT locus. The post-irradiation treatment of ascorbic acid did not alter the cell killing effect of neutron radiation. However, the mutagenicity was decreased, especially when the cells were irradiated with boron. Our results suggested that ascorbic acid scavenged long-lived radicals effectively and caused apparent protective effects against mutagenicity of boron neutron capture therapy

Oxidation in fish oil enriched mayonnaise : Ascorbic acid and low pH increase oxidative deterioration

DEFF Research Database (Denmark)

Jacobsen, Charlotte; Timm Heinrich, Maike; Meyer, Anne S.

2001-01-01

The effect of ascorbic acid (0-4000 ppm) and pH (3.8-6.2) on oxidation and levels of iron and copper in various fractions of mayonnaise enriched with 16% fish oil was investigated. Ascorbic acid induced release of iron from the assumed oil- water interface into the aqueous phase at all pH levels......, but this effect of ascorbic acid was strongest at low pH (pH 3.8- 4.2). Ascorbic acid generally promoted formation of volatile oxidation compounds and reduced the peroxide value in mayonnaises. Peroxide values and total volatiles generally increased with decreasing pH values, suggesting that low pH promoted...... oxidation. It is proposed that iron bridges between the egg yolk proteins low-density lipoproteins, lipovitellin, and phosvitin at the oil-water interface are broken at low pH values, whereby iron ions become accessible as oxidation initiators. In the presence of ascorbic acid, oxidation is further enhanced...

Ascorbic Acid Alleviates Water Stress in Young Peach Trees and Improves Their Performance after Rewatering

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Consuelo Penella

2017-09-01

Full Text Available Exogenous application of biochemicals has been found to improve water stress tolerance in herbaceous crops but there are limited studies on deciduous fruit trees. The goal of this research was to study if ascorbic acid applications could improve physiological mechanisms associated with water stress tolerance in young fruit trees. Ascorbic acid was foliarly applied at a concentration of 250 ppm to water-stressed and well-watered peach trees (control of two cultivars (‘Scarletprince’ and ‘CaroTiger’. Trees received either one or two applications, and 1 week after the second application all trees were rewatered to field capacity. Upon rewatering, CO2 assimilation and stomatal conductance of water-stressed ‘Scarletprince’ trees sprayed with ascorbic acid (one or two applications were similar to those of well-irrigated trees, but water-stressed trees that had not received ascorbic acid did not recover photosynthetical functions. Also, water status in sprayed water-stressed ‘Scarletprince’ trees was improved to values similar to control trees. On the other hand, water-stressed ‘CaroTiger’ trees needed two applications of ascorbic acid to reach values of CO2 assimilation similar to control trees but these applications did not improve their water status. In general terms, different response mechanisms to cope with water stress in presence of ascorbic acid were found in each cultivar, with ‘Scarletprince’ trees preferentially using proline as compatible solute and ‘CaroTiger’ trees relying on stomatal regulation. The application of ascorbic acid reduced cell membrane damage and increased catalase activity in water-stressed trees of both cultivars. These results suggest that foliar applications of ascorbic acid could be used as a management practice for improving water stress tolerance of young trees under suboptimal water regimes.

EFFECT OF PHYSICAL EXERCISE ON LIPID PEROXIDATION AND ANTIOXIDANT ASCORBIC ACID DEFENSE

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Ljiljana M. Popović

2006-06-01

Full Text Available Strenuous exercises greatly increase oxygen consumption in the whole body, especially in skeletal muscles. Large part of oxygen consumption is reduced to H2O and ATP, but smaller part (2-5% results in an increased leakage of electrons from the mitochondrial respiratory chain, forming various reactive oxygen species ─ ROS (O2˙¯, H2O2 i OH˙. These free radicals are capable of triggering a chain of damaging biochemical and physiological reactions (oxidative stress, lipid peroxidation,as a base for skeletal muscles damage after exercise. MDA (malondialdehide is a marker of exercise induced lipid peroxidation process. L–ascorbic acid is a major aqueous-phase antioxidant. To estimate antioxidant role of ascorbic acid we use rate between dehidroascorbate and ascorbate. In this paper those markers were determinated in 30 students, in rest and after treadmill running protocol (Bruce Treadmill Protocol. It was found that after the treadmill test , plasma MDA level had increased from 3,04 to 4,39 μM/L. Plasma ascorbic acid was also found to be higher after the treadmill test comparing to rest level (from 55,4 to 67,6 μM/L. DHA/A level in rest was 1,62 and after treadmill test it increased to 2,05. These results suggests that strenuous exercise increased process of lipid peroxidation, but in the same time increased ascorbic acid level in plasma and DHA/A rate indicates stronger antioxidant defense system.

The effects of xylitol and sorbitol on lysozyme- and peroxidase-related enzymatic and candidacidal activities.

Science.gov (United States)

Kim, Bum-Soo; Chang, Ji-Youn; Kim, Yoon-Young; Kho, Hong-Seop

2015-07-01

To investigate whether xylitol and sorbitol affect enzymatic and candidacidal activities of lysozyme, the peroxidase system, and the glucose oxidase-mediated peroxidase system. Xylitol and sorbitol were added to hen egg-white lysozyme, bovine lactoperoxidase, glucose oxidase-mediated peroxidase, and whole saliva in solution and on hydroxyapatite surfaces. The enzymatic activities of lysozyme, peroxidase, and glucose oxidase-mediated peroxidase were determined by the turbidimetric method, the NbsSCN assay, and production of oxidized o-dianisidine, respectively. Candidacidal activities were determined by comparing colony forming units using Candida albicans ATCC strains 10231, 11006, and 18804. While xylitol and sorbitol did not affect the enzymatic activity of hen egg-white lysozyme both in solution and on hydroxyapatite surfaces, they did inhibit the enzymatic activity of salivary lysozyme significantly in solution, but not on the surfaces. Xylitol and sorbitol enhanced the enzymatic activities of both bovine lactoperoxidase and salivary peroxidase significantly in a dose-dependent manner in solution, but not on the surfaces. Sorbitol, but not xylitol, inhibited the enzymatic activity of glucose oxidase-mediated peroxidase significantly. Both xylitol and sorbitol did not affect candidacidal activities of hen egg-white lysozyme, the bovine lactoperoxidase system, or the glucose oxidase-mediated bovine lactoperoxidase system. Xylitol and sorbitol inhibited salivary lysozyme activity, but enhanced both bovine lactoperoxidase and salivary peroxidase activities significantly in solution. Xylitol and sorbitol did not augment lysozyme- and peroxidase-related candidacidal activities. Copyright © 2015 Elsevier Ltd. All rights reserved.

Isolation and characterization of Cu/Zn-superoxide dismutase in Fasciola gigantica.

Science.gov (United States)

Lalrinkima, H; Raina, O K; Chandra, Dinesh; Jacob, Siju Susan; Bauri, R K; Chandra, Subhash; Yadav, H S; Singh, M N; Rialch, A; Varghese, A; Banerjee, P S; Kaur, Navneet; Sharma, Arvind

2015-01-01

A full-length complementary DNA (cDNA) encoding Cu/Zn-superoxide dismutase was isolated from Fasciola gigantica that on nucleotide sequencing showed a close homology (98.9%) with Cu/Zn-superoxide dismutase (SOD) of the temperate liver fluke, F. hepatica. Expression of the gene was found in all the three developmental stages of the parasite viz. adult, newly excysted juvenile and metacercaria at transcriptional level by reverse transcription-polymerase chain reaction (RT-PCR) and at the protein level by Western blotting. F. gigantica Cu/Zn-SOD cDNA was cloned and expressed in Escherichia coli. Enzyme activity of the recombinant protein was determined by nitroblue tetrazolium (NBT)-polyacrylamide gel electrophoresis (PAGE) and this activity was inactivated by hydrogen peroxide but not by sodium azide, indicating that the recombinant protein is Cu/Zn-SOD. The enzyme activity was relatively stable at a broad pH range of pH 4.0-10.0. Native Cu/Zn-superoxide dismutase protein was detected in the somatic extract and excretory-secretory products of the adult F. gigantica by Western blotting. NBT-PAGE showed a single Cu/Zn-SOD present in the somatic extract while three SODs are released ex vivo by the adult parasite. The recombinant superoxide dismutase did not react with the serum from buffaloes infected with F. gigantica. The role of this enzyme in defense by the parasite against the host reactive oxygen species is discussed. Copyright © 2015 Elsevier Inc. All rights reserved.

Metabolic Conversion of l-Ascorbic Acid to Oxalic Acid in Oxalate-accumulating Plants 1

Science.gov (United States)

Yang, Joan C.; Loewus, Frank A.

1975-01-01

l-Ascorbic acid-1-14C and its oxidation product, dehydro-l-ascorbic acid, produced labeled oxalic acid in oxalate-accumulating plants such as spinach seedlings (Spinacia oleracea) and the detached leaves of woodsorrel (Oxalis stricta and O. oregana), shamrock (Oxalis adenopylla), and begonia (Begonia evansiana). In O. oregana, conversion occurred equally well in the presence or absence of light. This relationship between l-ascorbic acid metabolism and oxalic acid formation must be given careful consideration in attempts to explain oxalic accumulation in plants. PMID:16659288

Ascorbic acid for the healing of skin wounds in rats

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CC. Lima

Full Text Available BACKGROUND: Healing is a complex process that involves cellular and biochemical events. Several medicines have been used in order to shorten healing time and avoid aesthetic damage. OBJECTIVE: to verify the topical effect of ascorbic acid for the healing of rats' skin wounds through the number of macrophages, new vessels and fibroblast verifications in the experimental period; and analyse the thickness and the collagen fibre organization in the injured tissue. METHODS: Male Rattus norvegicus weighing 270 ± 30 g were used. After thionembutal anesthesia, 15 mm transversal incisions were made in the animals' cervical backs. They were divided into two groups: Control Group (CG, n = 12 - skin wound cleaned with water and soap daily; Treated Group (TG, n = 12 - skin wound cleaned daily and treated with ascorbic acid cream (10%. Samples of skin were collected on the 3rd, 7th and 14th days. The sections were stained with hematoxylin-eosin and picrosirius red for morphologic analysis. The images were obtained and analysed by a Digital Analyser System. RESULTS: The ascorbic acid acted on every stage of the healing process. It reduced the number of macrophages, increased the proliferation of fibroblasts and new vessels, and stimulated the synthesis of thicker and more organized collagen fibres in the wounds when compared to CG. CONCLUSION: Ascorbic acid was shown to have anti-inflammatory and healing effects, guaranteeing a suiTable environment and conditions for faster skin repair.

Correlation between the potency of flavonoids for cytochrome c reduction and inhibition of cardiolipin-induced peroxidase activity.

Science.gov (United States)

Lagoa, Ricardo; Samhan-Arias, Alejandro K; Gutierrez-Merino, Carlos

2017-05-06

There are large differences between flavonoids to protect against apoptosis, a process in which cytochrome c (Cyt c) plays a key role. In this work, we show that 7 of 13 flavonoids studied have a capacity to reduce Cyt c similar or higher than ascorbate, the flavonols quercetin, kaempferol and myricetin, flavanol epigallocatechin-gallate, anthocyanidins cyanidin and malvidin, and the flavone luteolin. In contrast, the kaempferol 3(O)- and 3,4'(O)-methylated forms, the flavanone naringenin, and also apigenin and chrysin, had a negligible reducing capacity. Equilibrium dialysis and quenching of 1,6-diphenyl-1,3,5-hexatriene fluorescence experiments showed that flavonoids did not interfere with Cyt c binding to cardiolipin (CL)/phosphatidylcholine (PC) vesicles. However, the CL-induced loss of Cyt c Soret band intensity was largely attenuated by flavonoids, pointing out a stabilizing action against Cyt c unfolding in the complex. Moreover, flavonoids that behave as Cyt c reductants also inhibited the pro-apoptotic CL-induced peroxidase activity of Cyt c, indicating that modulation of Cyt c signaling are probable mechanisms behind the protective biological activities of flavonoids. © 2016 BioFactors, 43(3):451-468, 2017. © 2017 International Union of Biochemistry and Molecular Biology.

Eosinophil peroxidase signals via epidermal growth factor-2 to induce cell proliferation.

LENUS (Irish Health Repository)

Walsh, Marie-Therese

2011-11-01

Eosinophils exert many of their inflammatory effects in allergic disorders through the degranulation and release of intracellular mediators, including a set of cationic granule proteins that include eosinophil peroxidase. Studies suggest that eosinophils are involved in remodeling. In previous studies, we showed that eosinophil granule proteins activate mitogen-activated protein kinase signaling. In this study, we investigated the receptor mediating eosinophil peroxidase-induced signaling and downstream effects. Human cholinergic neuroblastoma IMR32 and murine melanoma B16.F10 cultures, real-time polymerase chain reaction, immunoprecipitations, and Western blotting were used in the study. We showed that eosinophil peroxidase caused a sustained increase in both the expression of epidermal growth factor-2 (HER2) and its phosphorylation at tyrosine 1248, with the consequent activation of extracellular-regulated kinase 1\\/2. This, in turn, promoted a focal adhesion kinase-dependent egress of the cyclin-dependent kinase inhibitor p27(kip) from the nucleus to the cytoplasm. Eosinophil peroxidase induced a HER2-dependent up-regulation of cell proliferation, indicated by an up-regulation of the nuclear proliferation marker Ki67. This study identifies HER2 as a novel mediator of eosinophil peroxidase signaling. The results show that eosinophil peroxidase, at noncytotoxic levels, can drive cell-cycle progression and proliferation, and contribute to tissue remodeling and cell turnover in airway disease. Because eosinophils are a feature of many cancers, these findings also suggest a role for eosinophils in tumorigenesis.

Thyroid peroxidase autoantibodies in euthyroid subjects

NARCIS (Netherlands)

Prummel, Mark F.; Wiersinga, Wilmar M.

2005-01-01

Thyroid peroxidase (TPO) is a key enzyme in the formation of thyroid hormones and a major autoantigen in autoimmune thyroid diseases. Titers of TPO antibodies also correlate with the degree of lymphocytic infiltration in euthyroid subjects, and they are frequently present in euthyroid subjects

Use of an immuno-peroxidase staining method for the detection of ...

African Journals Online (AJOL)

Immunopurified antigens of axenic E. histolytica were used to produce rabbit hyper-immune sera. Immunoglobulin G (IgG) was purified from hyper-immune sera and coupled to peroxidase using a two-step procedure. The IgG-peroxidase conjugate was then evaluated by detection of E. histolytica in 128 stool samples and ...

Effect of residual ascorbate on determination of nitrite in commercial cured meat products.

Science.gov (United States)

Fox, J B; Doerr, R C; Gates, R

1984-01-01

Residual ascorbate in cured meat slurries results in different amounts of pigment being produced from different Griess reagent combinations. The phenomenon was used to study residual ascorbate in commercial cured meat products which had a variety of textures, acidities, moisture and meat content, fat, homogeneity, initial nitrite, and processing conditions. Diluting and heating the samples according to the AOAC procedure did not completely eliminate the ascorbate interference, but making the sample alkaline did. Determining nitrite separately in supernate and precipitate from the first dilution showed the effect of heating to be the elimination of interferences and solubilization or extraction of nitrite from the precipitate.

Solubilities of magnesium-L-ascorbate, calcium-L-ascorbate, magnesium-L-glutamate, magnesium-D-gluconate, calcium-D-gluconate, calcium-D-heptagluconate, L-aspartic acid, and 3-nitrobenzoic acid in water

Energy Technology Data Exchange (ETDEWEB)

Mishelevich, Alexander [Department of Chemical Engineering, Ben Gurion University of the Negev, Beer Sheva 84105 (Israel); Apelblat, Alexander [Department of Chemical Engineering, Ben Gurion University of the Negev, Beer Sheva 84105 (Israel)], E-mail: apelblat@bgu.ac.il

2008-05-15

The solubility in water of magnesium-L-ascorbate, calcium-L-ascorbate, magnesium-L-glutamate, magnesium-D-gluconate, calcium-D-gluconate, calcium-D-heptagluconate, L-aspartic acid, and 3-nitrobenzoic acid was determined in the 278.15 K to 343.15 K temperature range. The solubility of these compounds served to permit the evaluation of the apparent molar enthalpies of solution.

Solubilities of magnesium-L-ascorbate, calcium-L-ascorbate, magnesium-L-glutamate, magnesium-D-gluconate, calcium-D-gluconate, calcium-D-heptagluconate, L-aspartic acid, and 3-nitrobenzoic acid in water

International Nuclear Information System (INIS)

Mishelevich, Alexander; Apelblat, Alexander

2008-01-01

The solubility in water of magnesium-L-ascorbate, calcium-L-ascorbate, magnesium-L-glutamate, magnesium-D-gluconate, calcium-D-gluconate, calcium-D-heptagluconate, L-aspartic acid, and 3-nitrobenzoic acid was determined in the 278.15 K to 343.15 K temperature range. The solubility of these compounds served to permit the evaluation of the apparent molar enthalpies of solution

Over-expression of ascorbate oxidase in the apoplast of transgenic tobacco results in altered ascorbate and glutathione redox states and increased sensitivity to ozone

DEFF Research Database (Denmark)

Sanmartin, Maite; Drogoudi, Pavlina D.; Lyons, Tom

2003-01-01

overexpressing plants exposed to 100 nmol mol-1 ozone for 7 h day-1 exhibited a substantial increase in foliar injury, and a greater pollutant-induced reduction in both the light-saturated rate of CO2 assimilation and the maximum in vivo rate of ribulose-1,5-bisphosphate carboxylase/oxygenase carboxylation......Transgenic tobacco (Nicotiana tabacum L. cv. Xanthi) plants expressing cucumber ascorbate oxidase (EC.1.10.3.3) were used to examine the role of extracellular ascorbic acid in mediating tolerance to the ubiquitous air pollutant, ozone (O3). Three homozygous transgenic lines, chosen on the basis...

Enthalpic characteristics of interactions occurring between an ascorbic acid and some saccharides in aqueous solutions

International Nuclear Information System (INIS)

Terekhova, Irina V.; Kulikov, Oleg V.; Titova, Elena S.

2004-01-01

The enthalpies of solution of mono- and disaccharides were measured in water and aqueous ascorbic acid solutions at 298.15 K using a calorimeter of solution. Enthalpies of transfer of saccharides from water to aqueous ascorbic acid solutions were derived, and enthalpic coefficients of pair interaction h xy were calculated according to MacMillan-Mayer theory. Interactions of ascorbic acid with D-fructose and sucrose are energetically favorable and characterized by negative h xy coefficients while h xy for the interactions occurring between ascorbic acid and α-D glucose, D-galactose and maltose are positive. The obtained results are interpreted in terms of the influence of structure and solvation of solutes on the thermodynamic parameters of their interaction in solutions

Pretreatment with ascorbic acid prevents lethal gastrointestinal syndrome in mice receiving a massive amount of radiation

International Nuclear Information System (INIS)

Yamamoto, Tetsuo; Kinoshita, Manabu; Shinomiya, Nariyoshi; Hiroi, Sadayuki; Sugasawa, Hidekazu; Majima, Takashi; Seki, Shuhji; Matsushita, Yoshitaro; Saitoh, Daizoh

2010-01-01

While bone marrow or stem cell transplantation can rescue bone marrow aplasia in patients accidentally exposed to a lethal radiation dose, radiation-induced irreversible gastrointestinal damage (GI syndrome) is fatal. We investigated the effects of ascorbic acid on radiation-induced GI syndrome in mice. Ascorbic acid (150 mg/kg/day) was orally administered to mice for 3 days, and then the mice underwent whole body irradiation (WBI). Bone marrow transplantation (BMT) 24 h after irradiation rescued mice receiving a WBI dose of less than 12 Gy. No mice receiving 14 Gy-WBI survived, because of radiation-induced GI syndrome, even if they received BMT. However, pretreatment with ascorbic acid significantly suppressed radiation-induced DNA damage in the crypt cells and prevented denudation of intestinal mucosa; therefore, ascorbic acid in combination with BMT rescued mice after 14 Gy-WBI. DNA microarray analysis demonstrated that irradiation up-regulated expressions of apoptosis-related genes in the small intestine, including those related to the caspase-9-mediated intrinsic pathway as well as the caspase-8-mediated extrinsic pathway, and down-regulated expressions of these genes in ascorbic acid-pretreated mice. Thus, pretreatment with ascorbic acid may effectively prevent radiation-induced GI syndrome. (author)

Lead induced dyslipidemia: The comparative effects of ascorbate ...

African Journals Online (AJOL)

R.N. UGBAJA

2013-04-10

Apr 10, 2013 ... Key words: Ascorbate, chelating agents, dyslipidemia, lead exposure, plumbism. .... elements like iron, zinc, calcium and a host of other divalent elements in ..... cholesterol synthesis and transport pathways may be adversely ...

Ascorbic acid supplementation diminishes microparticle elevations and neutrophil activation following SCUBA diving.

Science.gov (United States)

Yang, Ming; Barak, Otto F; Dujic, Zeljko; Madden, Dennis; Bhopale, Veena M; Bhullar, Jasjeet; Thom, Stephen R

2015-08-15

Predicated on evidence that diving-related microparticle generation is an oxidative stress response, this study investigated the role that oxygen plays in augmenting production of annexin V-positive microparticles associated with open-water SCUBA diving and whether elevations can be abrogated by ascorbic acid. Following a cross-over study design, 14 male subjects ingested placebo and 2-3 wk later ascorbic acid (2 g) daily for 6 days prior to performing either a 47-min dive to 18 m of sea water while breathing air (∼222 kPa N2/59 kPa O2) or breathing a mixture of 60% O2/balance N2 from a tight-fitting face mask at atmospheric pressure for 47 min (∼40 kPa N2/59 kPa O2). Within 30 min after the 18-m dive in the placebo group, neutrophil activation, and platelet-neutrophil interactions occurred, and the total number of microparticles, as well as subgroups bearing CD66b, CD41, CD31, CD142 proteins or nitrotyrosine, increased approximately twofold. No significant elevations occurred among divers after ingesting ascorbic acid, nor were elevations identified in either group after breathing 60% O2. Ascorbic acid had no significant effect on post-dive intravascular bubble production quantified by transthoracic echocardiography. We conclude that high-pressure nitrogen plays a key role in neutrophil and microparticle-associated changes with diving and that responses can be abrogated by dietary ascorbic acid supplementation. Copyright © 2015 the American Physiological Society.

Musa paradisiaca stem juice as a source of peroxidase and ligninperoxidase.

Science.gov (United States)

Vernwal, S K; Yadav, R S; Yadav, K D

2000-10-01

Musa paradisiaca stem juice has been shown to contain peroxidase activity of the order of 0.1 enzyme unit/ml. The Km values of this peroxidase for the substrates guaiacol and hydrogen peroxide are 2.4 and 0.28 mM respectively. The pH and temperature optima are 4.5 and 62.5 degrees C respectively. Like other peroxidases, it follows double displacement type mechanism. At low pH, Musa paradisiaca stem juice exhibits ligninperoxidase type activity. The pH optimum for ligninperoxidase type activity is 2.0 and the temperature optimum is 24 degrees C. The Km values for veratryl alcohol and n-propanol are 66 and 78 microM respectively.

Frequency of anti thyroid peroxidase antibody in patients of vitiligo

International Nuclear Information System (INIS)

Zhokhar, A.; Shaikh, Z.I.

2013-01-01

Objective: The objective of this study was to compare the frequency of anti thyroid peroxidase antibody in patients suffering from vitiligo with healthy control group. Type of Study: Case control study. Settings: Dermatology Department, Military Hospital, Rawalpindi, from 20th March 2010 to 20th July 2011. Material and Methods: Fifty clinically diagnosed patients of vitiligo, age = 18 yrs and both genders with no history of thyroid disease, past or current use of drugs for thyroid disorder or thyroid surgery were included as cases (Group A). Fifty healthy individuals with no evidence of vitiligo or thyroid disorder on history and physical examination and with no family history of vitiligo, matched for age and gender with cases, were included as control (Group B). Serum anti thyroid peroxidase (anti TPO) antibodies were measured using enzyme linked immunosorbent assay (ELISA) in both cases and control. Results: Eight (16%) patients in Group A were anti-thyroid peroxidase antibody positive and forty two (84%) patients were negative while one (2%) patient was anti-thyroid peroxidase antibody positive in Group B and forty nine (98%) patients were negative (p = 0.001). Conclusion: Anti TPO antibody is significantly more common in patients of vitiligo as compared to general population. (author)

Kinetics of ascorbic acid degradation in un-pasteurized Iranian lemon juice during regular storage conditions.

Science.gov (United States)

Abbasi, A; Niakousari, M

2008-05-15

The aim of this research was to determine shelf life stability of un-pasteurized lemon juice filled in clear or dark green glass bottles. Presence of light, time and temperature affect the ascorbic acid retention in citrus juices. Bottles were stored at room temperature (27 +/- 3 degrees C) and in the refrigerator (3 +/- 1 degrees C). Total soluble solids, total titrable acidity and pH value were measured every three weeks and analysis was carried out on ascorbic acid content by means of titration method in the presence of 2,6-dichlorophenol indophenol. The study was carried out for 12 weeks after which slight changes in color, taste and apparent texture in some samples were observed and ascorbic acid content reduced by 50%. Soluble solids content, pH value and total acidity were 5.5 degrees Brix, 2.73 and 5 g/100 mL, respectively which appeared not to be significantly influenced by storage time or conditions. Ascorbic acid content initially at 38.50 mg/100 mL was sharply reduced to about 22 mg/100 mL within the first three weeks of storage. The final ascorbic acid content of all samples was about 15 mg/100 mL. The deteriorative reaction of ascorbic acid in the juice at all conditions followed a first-order kinetic model with activation energy of 137 cal mol(-1).

Thermal stability of L-ascorbic acid and ascorbic acid oxidase in broccoli (Brassica oleracea var. italica).

Science.gov (United States)

Munyaka, Ann Wambui; Makule, Edna Edward; Oey, Indrawati; Van Loey, Ann; Hendrickx, Marc

2010-05-01

The thermal stability of vitamin C (including l-ascorbic acid [l-AA] and dehydroascorbic acid [DHAA]) in crushed broccoli was evaluated in the temperature range of 30 to 90 degrees C whereas that of ascorbic acid oxidase (AAO) was evaluated in the temperature range of 20 to 95 degrees C. Thermal treatments (for 15 min) of crushed broccoli at 30 to 60 degrees C resulted in conversion of l-AA to DHAA whereas treatments at 70 to 90 degrees C retained vitamin C as l-AA. These observations indicated that enzymes (for example, AAO) could play a major role in the initial phase (that is, oxidation of l-AA to DHAA) of vitamin C degradation in broccoli. Consequently, a study to evaluate the temperature-time conditions that could result in AAO inactivation in broccoli was carried out. In this study, higher AAO activity was observed in broccoli florets than stalks. During thermal treatments for 10 min, AAO in broccoli florets and stalks was stable until around 50 degrees C. A 10-min thermal treatment at 80 degrees C almost completely inactivated AAO in broccoli. AAO inactivation followed 1st order kinetics in the temperature range of 55 to 65 degrees C. Based on this study, a thermal treatment above 70 degrees C is recommended for crushed vegetable products to prevent oxidation of l-AA to DHAA, the onset of vitamin C degradation. The results reported in this study are applicable for both domestic and industrial processing of vegetables into products such as juices, soups, and purees. In this report, we have demonstrated that processing crushed broccoli in a temperature range of 30 to 60 degrees C could result in the conversion of l-ascorbic acid to dehydroascorbic (DHAA), a very important reaction in regard to vitamin C degradation because DHAA could be easily converted to other compounds that do not have the biological activity of vitamin C.

Effect of sodium ascorbate and sodium nitrite on protein and lipid oxidation in dry fermented sausages.

Science.gov (United States)

Berardo, A; De Maere, H; Stavropoulou, D A; Rysman, T; Leroy, F; De Smet, S

2016-11-01

The effects of sodium nitrite and ascorbate on lipid and protein oxidation were studied during the ripening process of dry fermented sausages. Samples were taken at day 0, 2, 8, 14, 21 and 28 of ripening to assess lipid (malondialdehyde) and protein (carbonyls and sulfhydryl groups) oxidation. Sodium ascorbate and nitrite were separately able to reduce the formation of malondialdehyde. Their combined addition resulted in higher amounts of carbonyl compounds compared to their separate addition or the treatment without any of both compounds. Moreover, sodium nitrite limited the formation of γ-glutamic semialdehyde whereas sodium ascorbate showed a pro-oxidant effect. A loss of thiol groups was observed during ripening, which was not affected by the use of sodium ascorbate nor sodium nitrite. In conclusion, sodium nitrite and ascorbate affected protein and lipid oxidation in different manners. The possible pro-oxidant effect of their combined addition on carbonyl formation might influence the technological and sensory properties of these products. Copyright © 2016 Elsevier Ltd. All rights reserved.

Uranium and cadmium provoke different oxidative stress responses in Lemna minor L.

Science.gov (United States)

Horemans, N; Van Hees, M; Van Hoeck, A; Saenen, E; De Meutter, T; Nauts, R; Blust, R; Vandenhove, H

2015-01-01

Common duckweed (Lemna minor L.) is ideally suited to test the impact of metals on freshwater vascular plants. Literature on cadmium (Cd) and uranium (U) oxidative responses in L. minor are sparse or, for U, non-existent. It was hypothesised that both metals impose concentration-dependent oxidative stress and growth retardation on L. minor. Using a standardised 7-day growth inhibition test, the adverse impact of these metals on L. minor growth was confirmed, with EC50 values for Cd and U of 24.1 ± 2.8 and 29.5 ± 1.9 μm, respectively, and EC10 values of 1.5 ± 0.2 and 6.5 ± 0.9 μm, respectively. The metal-induced oxidative stress response was compared through assessing the activity of different antioxidative enzymes [catalase, glutathione reductase, superoxide dismutase (SOD), ascorbate peroxidase (APOD), guaiacol peroxidase (GPOD) and syringaldizyne peroxidase (SPOD)]. Significant changes in almost all antioxidative enzymes indicated their importance in counteracting the U- and Cd-imposed oxidative burden. However, some striking differences were also observed. For activity of APODs and SODs, a biphasic but opposite response at low Cd compared to U concentrations was found. In addition, Cd (0.5-20 μm) strongly enhanced plant GPOD activity, whereas U inhibited it. Finally, in contrast to Cd, U up to 10 μm increased the level of chlorophyll a and b and carotenoids. In conclusion, although U and Cd induce similar growth arrest in L. minor, the U-induced oxidative stress responses, studied here for the first time, differ greatly from those of Cd. © 2014 German Botanical Society and The Royal Botanical Society of the Netherlands.

Platelet crossmatch tests using radiolabelled staphylococcal protein A or peroxidase anti-peroxidase in alloimmunised patients

International Nuclear Information System (INIS)

Yam, P.; Petz, L.D.; Scott, E.P.; Santos, S.

1984-01-01

Refractoriness to random-donor platelets as a result of alloimmunization remains a major problem in long-term platelet transfusion therapy despite the use of HLA-matched platelets. A study has been made of two methods for detection of platelet associated IgG as platelet crossmatch tests for the selection of platelet donors. These methods use radiolabelled staphylococcal protein A( 125 I-SPA) and peroxidase anti-peroxidase (PAP), respectively. One hundred and ten crossmatch tests using 125 I-SPA were performed retrospectively in 18 alloimmunized patients. The results indicated that the predictive value of a positive or a negative test was 87%; the sensitivity was 73% and the specificity was 95%. Results with the PAP test were similar. The HLA types were known for 48 donor-recipient pairs. With few exceptions, there was a correlation between the results of the platelet crossmatch tests and the effectiveness of platelet transfusion regardless of the degree of HLA match. These results indicate that platelet crossmatch tests may be valuable even when closely HLA matched donors are not available. A large-scale prospective study is warranted, particularly in highly immunized patients. (author)

A putative peroxidase cDNA from turnip and analysis of the encoded protein sequence.

Science.gov (United States)

Romero-Gómez, S; Duarte-Vázquez, M A; García-Almendárez, B E; Mayorga-Martínez, L; Cervantes-Avilés, O; Regalado, C

2008-12-01

A putative peroxidase cDNA was isolated from turnip roots (Brassica napus L. var. purple top white globe) by reverse transcriptase-polymerase chain reaction (RT-PCR) and rapid amplification of cDNA ends (RACE). Total RNA extracted from mature turnip roots was used as a template for RT-PCR, using a degenerated primer designed to amplify the highly conserved distal motif of plant peroxidases. The resulting partial sequence was used to design the rest of the specific primers for 5' and 3' RACE. Two cDNA fragments were purified, sequenced, and aligned with the partial sequence from RT-PCR, and a complete overlapping sequence was obtained and labeled as BbPA (Genbank Accession No. AY423440, named as podC). The full length cDNA is 1167bp long and contains a 1077bp open reading frame (ORF) encoding a 358 deduced amino acid peroxidase polypeptide. The putative peroxidase (BnPA) showed a calculated Mr of 34kDa, and isoelectric point (pI) of 4.5, with no significant identity with other reported turnip peroxidases. Sequence alignment showed that only three peroxidases have a significant identity with BnPA namely AtP29a (84%), and AtPA2 (81%) from Arabidopsis thaliana, and HRPA2 (82%) from horseradish (Armoracia rusticana). Work is in progress to clone this gene into an adequate host to study the specific role and possible biotechnological applications of this alternative peroxidase source.

Effects of acetylcysteine and probucol on contrast medium-induced depression of intrinsic renal glutathione peroxidase activity in diabetic rats.

Science.gov (United States)

Yen, Hsueh-Wei; Lee, Hsiang-Chun; Lai, Wen-Te; Sheu, Sheng-Hsiung

2007-04-01

Antioxidants such as N-acetylcysteine and probucol have been used to protect patients from contrast media-induced nephrotoxicity. The mechanisms underlying these protective effects are not well understood. We hypothesized that acetylcysteine and probucol alter the activity of endogenous antioxidant enzyme activity. Four weeks after induction of diabetes with streptozotocin, diabetic and nondiabetic rats were divided into three groups. Group 1 rats did not receive any antioxidant agents. Group 2 rats were treated with acetylcysteine and group 3 rats with probucol for 1 week before injection of the contrast medium diatrizoate (DTZ). We found that diabetic rats had higher renal glutathione peroxidase (GPx) activity than normal rats. DTZ suppressed renal GPx activity significantly in both group 1 diabetic and normal rats. Interestingly, renal GPx activity in both diabetic and normal rats pretreated with acetylcysteine or probucol was not inhibited by DTZ. Renal superoxide dismutase (SOD) increased significantly in normal rats after DTZ injection, but not in diabetic rats. Finally, acetylcysteine or probucol did not significantly influence renal SOD. These findings suggest that the renal protective effects of acetylcysteine and probucol against contrast-induced oxidative stress and nephrotoxicity may be mediated by altering endogenous GPx activity.

The glutamate aspartate transporter (GLAST) mediates L-glutamate-stimulated ascorbate-release via swelling-activated anion channels in cultured neonatal rodent astrocytes.

Science.gov (United States)

Lane, Darius J R; Lawen, Alfons

2013-03-01

Vitamin C (ascorbate) plays important neuroprotective and neuromodulatory roles in the mammalian brain. Astrocytes are crucially involved in brain ascorbate homeostasis and may assist in regenerating extracellular ascorbate from its oxidised forms. Ascorbate accumulated by astrocytes can be released rapidly by a process that is stimulated by the excitatory amino acid, L-glutamate. This process is thought to be neuroprotective against excitotoxicity. Although of potential clinical interest, the mechanism of this stimulated ascorbate-release remains unknown. Here, we report that primary cultures of mouse and rat astrocytes release ascorbate following initial uptake of dehydroascorbate and accumulation of intracellular ascorbate. Ascorbate-release was not due to cellular lysis, as assessed by cellular release of the cytosolic enzyme lactate dehydrogenase, and was stimulated by L-glutamate and L-aspartate, but not the non-excitatory amino acid L-glutamine. This stimulation was due to glutamate-induced cellular swelling, as it was both attenuated by hypertonic and emulated by hypotonic media. Glutamate-stimulated ascorbate-release was also sensitive to inhibitors of volume-sensitive anion channels, suggesting that the latter may provide the conduit for ascorbate efflux. Glutamate-stimulated ascorbate-release was not recapitulated by selective agonists of either ionotropic or group I metabotropic glutamate receptors, but was completely blocked by either of two compounds, TFB-TBOA and UCPH-101, which non-selectively and selectively inhibit the glial Na(+)-dependent excitatory amino acid transporter, GLAST, respectively. These results suggest that an impairment of astrocytic ascorbate-release may exacerbate neuronal dysfunction in neurodegenerative disorders and acute brain injury in which excitotoxicity and/or GLAST deregulation have been implicated.

Sensitive spectrophotometric determination of ascorbic acid in drugs and foods using surface plasmon resonance band of silver nanoparticles

Directory of Open Access Journals (Sweden)

Kobra Zarei

2015-12-01

Full Text Available A simple and sensitive procedure was proposed for spectrophotometric determination of ascorbic acid. It was found that the reduction of Ag+ to silver nanoparticles (Ag-NPs by ascorbic acid in the presence of polyvinylpyrrolidone (PVP as a stabilizing agent produce very intense surface plasmon resonance peak of Ag-NPs. The plasmon absorbance of the Ag-NPs at λ = 440 nm allows the quantitative spectrophotometric detection of the ascorbic acid. The calibration curve was linear with concentration of ascorbic acid in the range of 0.5–60 μM. The detection limit was obtained as 0.08 μM. The influence of potential interfering substances on the determination of ascorbic acid was studied. The proposed method was successfully applied for the determination of ascorbic acid in some powdered drink mixtures, commercial orange juice, natural orange juice, vitamin C injection, effervescent tablet, and multivitamin tablet.

CDNA cloning, characterization and expression of an endosperm-specific barley peroxidase

DEFF Research Database (Denmark)

Rasmussen, Søren Kjærsgård; Welinder, K.G.; Hejgaard, J.

1991-01-01

A barley peroxidase (BP 1) of pI ca. 8.5 and M(r) 37000 has been purified from mature barley grains. Using antibodies towards peroxidase BP 1, a cDNA clone (pcR7) was isolated from cDNA expression library. The nucleotide sequence of pcR7 gave a derived amino acid sequence identical to the 158 C...

Increased expression of native cytosolic Cu/Zn superoxide dismutase and ascorbate peroxidase improves tolerance to oxidative and chilling stresses in cassava (Manihot esculenta Crantz)

OpenAIRE

Xu, Jia; Yang, Jun; Duan, Xiaoguang; Jiang, Yueming; Zhang, Peng

2014-01-01

Background Cassava (Manihot esculenta Crantz) is a tropical root crop, and is therefore, extremely sensitive to low temperature; its antioxidative response is pivotal for its survival under stress. Timely turnover of reactive oxygen species (ROS) in plant cells generated by chilling-induced oxidative damages, and scavenging can be achieved by non-enzymatic and enzymatic reactions in order to maintain ROS homeostasis. Results Transgenic cassava plants that co-express cytosolic superoxide dismu...

Application of titanium oxide nanotube films containing gold nanoparticles for the electroanalytical determination of ascorbic acid

Energy Technology Data Exchange (ETDEWEB)

Hosseini, Mir Ghasem, E-mail: mg-hosseini@tabrizu.ac.ir; Faraji, Masoud; Momeni, Mohamad Mohsen

2011-03-31

Au/TiO{sub 2}/Ti electrodes have been prepared by galvanic deposition of gold particles on TiO{sub 2} nanotube substrates. Titanium oxide nanotubes are fabricated by anodizing titanium foil in a Dimethyl Sulfoxide electrolyte containing fluoride. The scanning electron microscopy results indicated that gold particles are homogeneously deposited on the surface of TiO{sub 2} nanotubes. The TiO{sub 2} layers consist of individual tubes of about 40-80 nm diameters. The electro-catalytic behavior of Au/TiO{sub 2}/Ti and flat gold electrodes for the ascorbic acid electro-oxidation was studied by cyclic voltammetry. The results showed that the flat gold electrode is not suitable for the oxidation of ascorbic acid. However, the Au/TiO{sub 2}/Ti electrodes are shown to possess catalytic activity toward the oxidation reaction. Catalytic oxidation peak current showed a linear dependence on the ascorbic acid concentration and a linear calibration curve is obtained in the concentration range of 1-5 mM of ascorbic acid. Also, determination of ascorbic acid in real samples was evaluated. The obtained results were found to be satisfactory. Finally the effects of interference on the detection of ascorbic acid were investigated.

Obtenção de nova fonte de peroxidase de folha de Copaifera langsdorffii Desf. com alta atividade Obtention of a new source of peroxidase from Copaifera langsdorffii leaf, Desf. with high activity

Directory of Open Access Journals (Sweden)

Hermelinda Penha Freire Maciel

2006-12-01

Full Text Available Objetivou-se neste trabalho extrair peroxidase de folha de Copaifera langsdorffii (COP, medir sua atividade, compará-la com a peroxidase de raiz forte (Horseradish peroxidase - HRP e determinar o pH ótimo, a melhor solução extratora e o efeito de aditivos sobre a atividade da COP. Os resultados mostraram que a COP atingiu 81,6% da atividade de HRP e a faixa de pH ótimo foi de 5,5 a 6,0. A melhor solução extratora da enzima foi o tampão fosfato de sódio 50 mM, pH 6,0 e o melhor aditivo foi o PVPP. Concluindo, a COP apresenta atividade mais alta que outras peroxidases de diferentes fontes citadas na literatura.The purpose of this work was to extract peroxidase from Copaifera langsdorffii leaves (COP, measure its activity, compare it to that of Horseradish peroxidase and determine the optimum pH, the best extraction solution and the effect of additives on the COP activity. The results showed that COP has 81.6% of the activity of HRP and an optimum pH range between 5.5-6.0. The best extraction solution was a sodium phosphate buffer 50 mM, pH 6.0 and the best additive was PVPP. In conclusion, COP presents higher activity than peroxidases from different sources reported in the literature.

Extraction of erythrocyte enzymes for the preparation of polyhemoglobin-catalase-superoxide dismutase.

Science.gov (United States)

Gu, Jingsong; Chang, Thomas Ming Swi

2009-01-01

In sustained severe ischemia, reperfusion with oxygen carriers may result in ischemia-reperfusion injuries because of the release of damaging oxygen radicals. A nanobiotechnology-based polyhemogloin-calatase-superoxide dismutase can prevent this because the oxygen carrier, polyhemoglobin, is linked to antioxidant enzymes, catalase and superoxide dismutase. However, these antioxidant enzymes come from nonhuman sources and recombinant human enzymes are expensive. This paper describes our study on extracting these enzymes from red blood cells and analyzing the amount of enzymes needed for adequate protection from ischemia-reperfusion.

Superoxide anion production and superoxide dismutase and catalase activities in Coxiella burnetii.

OpenAIRE

Akporiaye, E T; Baca, O G

1983-01-01

Coxiella burnetii was examined for superoxide anion (O2-) production and superoxide dismutase and catalase activities. The organism generated O2- at pH 4.5 but not at pH 7.4. The rickettsia displayed superoxide dismutase activity distinguishable from that of the host cell (L-929 mouse fibroblast). Catalase activity was maximal at pH 7.0 and diminished at pH 4.5. These enzymes may account, in part, for the ability of this obligate intracellular parasite to survive within phagocytes.

Effect of the air pollution by heavy metals in the tree leaves in the metropolitan area of Toluca Valley

International Nuclear Information System (INIS)

Ledesma O, C. I.

2014-01-01

Leaves of two tree species: Juniperus sp and Ligustrum sp were studied as indicators of pollution heavy metals (Mn, Fe, Cu, Zn and Pb) in the atmosphere of the Metropolitan Area of the Toluca Valley. Bio markers of catalase, superoxide dismutase, ascorbate peroxidase, guaiacol, proteins and pigments were measured in order to determine the effects to atmospheric stress caused by heave metals during two periods in the year (December 2012 and May 2013). Metals were quantified in dry deposit and tissue on trees tissue leaves using the technique of Energy Dispersive X-ray Fluorescence Spectroscopy and Total Reflection X-ray Fluorescence Spectroscopy respectively. The results show greater response of enzyme inhibition in Juniperus sp. species, with decreased protein content and increased lipid peroxidation at sites with higher content of metals in tissue belonging to urban areas with increased industrial activity and traffic flow. In dry deposit bioavailability factor of metals was Fe>Mn> Zn> Cu>Pb for the first time of sampling and Fe>Mn> Cu> Zn>Pb for the second sampling period. (Author)

Proteomic and biochemical basis for enhanced growth yield of Enterobacter sp. LCR1 on insoluble phosphate medium.

Science.gov (United States)

Kumar, Arvind; Rai, Lal Chand

2015-01-01

Proteomics and biochemical analyses were used to unravel the basis for higher growth yield of Enterobacter sp. LCR1 on insoluble phosphate medium compared to soluble. Proteomic analysis using 2-DE, MALDI-TOF/MS and LC-MS revealed the involvement of nine proteins. Down-regulation of fructose bisphosphate aldolase with decreased concentrations of glucose-6-phosphate and fructose-6-phosphate indicated diminished glycolysis. However, up-regulation of phosphoglycerate mutase, increase in the activities of 6-phosphogluconate dehydratase, 2-keto-3-deoxy-6-phosphogluconate aldolase and 6-phosphogluconate dehydrogenase suggested induction of Entner-Doudoroff and pentose phosphate pathways. These pathways generate sufficient energy from gluconic acid, which is also used for biosynthesis as indicated by up-regulation of elongation factor Tu, elongation factor G and protein disulfide isomerase. Increased reactive oxygen species (ROS) formation resulting from organic acid oxidation leads to overexpressed manganese superoxide dismutase and increased activities of catalase and ascorbate peroxidase. Thus the organism uses gluconate instead of glucose for energy, while alleviating extra ROS formation by oxidative defense enzymes. Copyright © 2014 Elsevier GmbH. All rights reserved.

Modulation of Antioxidant Defense System Is Associated with Combined Drought and Heat Stress Tolerance in Citrus.

Science.gov (United States)

Zandalinas, Sara I; Balfagón, Damián; Arbona, Vicent; Gómez-Cadenas, Aurelio

2017-01-01

Drought and high temperatures are two major abiotic stress factors that often occur simultaneously in nature, affecting negatively crop performance and yield. Moreover, these environmental challenges induce oxidative stress in plants through the production of reactive oxygen species (ROS). Carrizo citrange and Cleopatra mandarin are two citrus genotypes with contrasting ability to cope with the combination of drought and heat stress. In this work, a direct relationship between an increased antioxidant activity and stress tolerance is reported. According to our results, the ability of Carrizo plants to efficiently coordinate superoxide dismutase (SOD), ascorbate peroxidase (APX), catalase (CAT), and glutathione reductase (GR) activities involved in ROS detoxification along with the maintenance of a favorable GSH/GSSG ratio could be related to their relative tolerance to this stress combination. On the other hand, the increment of SOD activity and the inefficient GR activation along with the lack of CAT and APX activities in Cleopatra plants in response to the combination of drought and heat stress, could contribute to an increased oxidative stress and the higher sensibility of this citrus genotype to this stress combination.

A study on toxicity of gasoline and GM-10 on liver of mice and it's amelioration by black tea extract.

Science.gov (United States)

Verma, Ramtej Jayram; Dave, Manjeet; Mathuria, Neeta

2008-01-01

The aim of present study is to investigate the ameliorative effect of black tea extract on gasoline and GM-10 induced toxicity in liver of mice. Eighty healthy male mice weighing 38-40 g approximately were divided into eight groups which included untreated control and various treated groups. Mice were treated with Gasoline 462 mg/kg/day and GM-10 low dose (206 mg/kg/day) and high dose (412 mg/kg/day) subcutaneously for 30 days. Black tea extract was given as 2 g/100 mL drinking water (2% w/v) instead of pure drinking water. All the animals were sacrificed on 31st day by cervical dislocation and livers were isolated and weighed. Parameters such as lipid peroxidation, catalase, superoxide dismutase, glutathione peroxidase, glutathione and total ascorbic acid were studied. The results revealed dose-dependent toxicity of gasoline and GM-10 on liver. Administration of black tea extract ameliorates this toxicity of gasoline and GM-10 in liver of mice. This proves the effective ameliorative effect of black tea extract.

Resveratrol Protects the Brain of Obese Mice from Oxidative Damage

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Shraddha D. Rege

2013-01-01

Full Text Available Resveratrol (3,5,4′-trihydroxy-trans-stilbene is a polyphenolic phytoalexin that exerts cardioprotective, neuroprotective, and antioxidant effects. Recently it has been shown that obesity is associated with an increase in cerebral oxidative stress levels, which may enhance neurodegeneration. The present study evaluates the neuroprotective action of resveratrol in brain of obese (ob/ob mice. Resveratrol was administered orally at the dose of 25 mg kg−1 body weight daily for three weeks to lean and obese mice. Resveratrol had no effect on body weight or blood glucose levels in obese mice. Lipid peroxides were significantly increased in brain of obese mice. The enzymatic antioxidants superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase, glucose-6-phosphate dehydrogenase and nonenzymatic antioxidants tocopherol, ascorbic acid, and glutathione were decreased in obese mice brain. Administration of resveratrol decreased lipid peroxide levels and upregulated the antioxidant activities in obese mice brain. Our findings indicate a neuroprotective effect of resveratrol by preventing oxidative damage in brain tissue of obese mice.

Effect of the air pollution by heavy metals in the tree leaves in the metropolitan area of Toluca Valley; Efecto de la contaminacion atmosferica por metales pesados en las hojas de los arboles de la zona metropolitana del Valle de Toluca

Energy Technology Data Exchange (ETDEWEB)

Ledesma O, C. I.

2014-07-01

Leaves of two tree species: Juniperus sp and Ligustrum sp were studied as indicators of pollution heavy metals (Mn, Fe, Cu, Zn and Pb) in the atmosphere of the Metropolitan Area of the Toluca Valley. Bio markers of catalase, superoxide dismutase, ascorbate peroxidase, guaiacol, proteins and pigments were measured in order to determine the effects to atmospheric stress caused by heave metals during two periods in the year (December 2012 and May 2013). Metals were quantified in dry deposit and tissue on trees tissue leaves using the technique of Energy Dispersive X-ray Fluorescence Spectroscopy and Total Reflection X-ray Fluorescence Spectroscopy respectively. The results show greater response of enzyme inhibition in Juniperus sp. species, with decreased protein content and increased lipid peroxidation at sites with higher content of metals in tissue belonging to urban areas with increased industrial activity and traffic flow. In dry deposit bioavailability factor of metals was Fe>Mn> Zn> Cu>Pb for the first time of sampling and Fe>Mn> Cu> Zn>Pb for the second sampling period. (Author)

Salt stress-induced changes in antioxidative defense system and proteome profiles of salt-tolerant and sensitive Frankia strains.

Science.gov (United States)

Srivastava, Amrita; Singh, Anumeha; Singh, Satya S; Mishra, Arun K

2017-04-16

An appreciation of comparative microbial survival is most easily done while evaluating their adaptive strategies during stress. In the present experiment, antioxidative and whole cell proteome variations based on spectrophotometric analysis and SDS-PAGE and 2-dimensional gel electrophoresis have been analysed among salt-tolerant and salt-sensitive Frankia strains. This is the first report of proteomic basis underlying salt tolerance in these newly isolated Frankia strains from Hippophae salicifolia D. Don. Salt-tolerant strain HsIi10 shows higher increment in the contents of superoxide dismutase, catalase and ascorbate peroxidase as compared to salt-sensitive strain HsIi8. Differential 2-DGE profile has revealed differential profiles for salt-tolerant and salt-sensitive strains. Proteomic confirmation of salt tolerance in the strains with inbuilt efficiency of thriving in nitrogen-deficient locales is a definite advantage for these microbes. This would be equally beneficial for improvement of soil nitrogen status. Efficient protein regulation in HsIi10 suggests further exploration for its potential use as biofertilizer in saline soils.

Halide peroxidase in tissues that interact with bacteria in the host squid Euprymna scolopes.

Science.gov (United States)

Small, A L; McFall-Ngai, M J

1999-03-15

An enzyme with similarities to myeloperoxidase, the antimicrobial halide peroxidase in mammalian neutrophils, occurs abundantly in the light organ tissue of Euprymna scolopes, a squid that maintains a beneficial association with the luminous bacterium Vibrio fischeri. Using three independent assays typically applied to the analysis of halide peroxidase enzymes, we directly compared the activity of the squid enzyme with that of human myeloperoxidase. One of these methods, the diethanolamine assay, confirmed that the squid peroxidase requires halide ions for its activity. The identification of a halide peroxidase in a cooperative bacterial association suggested that this type of enzyme can function not only to control pathogens, but also to modulate the interactions of host animals with their beneficial partners. To determine whether the squid peroxidase functions under both circumstances, we examined its distribution in a variety of host tissues, including those that typically interact with bacteria and those that do not. Tissues interacting with bacteria included those that have specific cooperative associations with bacteria (i.e., the light organ and accessory nidamental gland) and those that have transient nonspecific interactions with bacteria (i.e., the gills, which clear the cephalopod circulatory system of invading microorganisms). These bacteria-associated tissues were compared with the eye, digestive gland, white body, and ink-producing tissues, which do not typically interact directly with bacteria. Peroxidase enzyme assays, immunocytochemical localization, and DNA-RNA hybridizations showed that the halide-dependent peroxidase is consistently expressed in high concentration in tissues that interact bacteria. Elevated levels of the peroxidase were also found in the ink-producing tissues, which are known to have enzymatic pathways associated with antimicrobial activity. Taken together, these data suggest that the host uses a common biochemical response to

Experience of application of ascorbate chitosan in the treatment of periodontal disease

Directory of Open Access Journals (Sweden)

Bulkina N.V.

2013-09-01

Full Text Available Aim. To study the clinical anti-inflammatory effect of gel form 8% ascorbate chitozan in treatment of inflammatory periodontal disease. Material and methods. The study included 30 patients: 10 patients with chronic catarrhal gingivitis, 10 patients with chronic generalized periodontitis mild and 10 moderate. Criteria for inclusion of patients in the study: age between 18 and 45 years old, reliable diagnosis, informed consent of the patient. Case history of the disease duration from one to five years. The state of periodontal tissue was evaluated clinically and radiographically by intraoral radiography. According to treatment methods patients were divided into groups: group 1 underwent traditional treatment, group 2 was treated with the use of applications of 8% of ascorbate chitosan on the area of papillae and marginal gingiva with the capture of 1-2 cm of the mucous membrane of the alveolar process. The duration of treatment was 15 minutes daily for 10 days. Results. The patterns suggest that the therapeutic effect of ascorbate chitazan caused prolonged sanation of periodontal pockets due to the antibacterial activity of chitazan. Conclusion. The data show that regeneration in patients who have a combined treatment included ascorbate chitosan has been more rapid and complete than similar processes in periodontal patients treated in a traditional way.

Kinetic mechanism and nucleotide specificity of NADH peroxidase

International Nuclear Information System (INIS)

Stoll, V.S.; Blanchard, J.S.

1988-01-01

NADH peroxidase is a flavoprotein isolated from Streptococcus faecalis which catalyzes the pyridine nucleotide-dependent reduction of hydrogen peroxide to water. Initial velocity, product, and dead-end inhibition studies have been performed at pH 7.5 and support a ping-pong kinetic mechanism. In the absence of hydrogen peroxide, both transhydrogenation between NADH and thioNAD, and isotope exchange between [ 14 C]NADH and NAD, have been demonstrated, although in both these experiments, the maximal velocity of nucleotide exchange was less than 1.5% the maximal velocity of the peroxidatic reaction. We propose that NADH binds tightly to both oxidized and two-electron reduced enzyme. NADH oxidation proceeds stereospecifically with the transfer of the 4S hydrogen to enzyme, and then, via exchange, to water. No primary tritium kinetic isotope effect was observed, and no statistically significant primary deuterium kinetic isotope effects on V/K were determined, although primary deuterium kinetic isotope effects on V were observed in the presence and absence of sodium acetate. NADH peroxidase thus shares with other flavoprotein reductases striking kinetic, spectroscopic, and stereochemical similarities. On this basis, we propose a chemical mechanism for the peroxide cleaving reaction catalyzed by NADH peroxidase which involves the obligate formation of a flavinperoxide, and peroxo bond cleavage by nucleophilic attack by enzymatic dithiols

Inhibition of cell proliferation and migration by oxidative stress from ascorbate-driven juglone redox cycling in human bladder-derived T24 cells

Energy Technology Data Exchange (ETDEWEB)

Kviecinski, M.R., E-mail: mrkviecinski@hotmail.com [Laboratorio de Bioquimica Experimental, Departamento de Bioquimica, Universidade Federal de Santa Catarina, Florianopolis (Brazil); Pedrosa, R.C., E-mail: rozangelapedrosa@gmail.com [Laboratorio de Bioquimica Experimental, Departamento de Bioquimica, Universidade Federal de Santa Catarina, Florianopolis (Brazil); Felipe, K.B., E-mail: kakabettega@yahoo.com.br [Laboratorio de Bioquimica Experimental, Departamento de Bioquimica, Universidade Federal de Santa Catarina, Florianopolis (Brazil); Farias, M.S., E-mail: mirellesfarias@hotmail.com [Laboratorio de Bioquimica Experimental, Departamento de Bioquimica, Universidade Federal de Santa Catarina, Florianopolis (Brazil); Glorieux, C., E-mail: christophe.glorieux@uclouvain.be [Toxicology and Cancer Biology Research Group, Louvain Drug Research Institute, Universite Catholique de Louvain, 73 Avenue E. Mounier, GTOX 7309, 1200 Brussels (Belgium); Valenzuela, M., E-mail: mavalenzuela@med.uchile.cl [Toxicology and Cancer Biology Research Group, Louvain Drug Research Institute, Universite Catholique de Louvain, 73 Avenue E. Mounier, GTOX 7309, 1200 Brussels (Belgium); Sid, B., E-mail: brice.sid@uclouvain.be [Toxicology and Cancer Biology Research Group, Louvain Drug Research Institute, Universite Catholique de Louvain, 73 Avenue E. Mounier, GTOX 7309, 1200 Brussels (Belgium); and others

2012-05-04

Highlights: Black-Right-Pointing-Pointer The cytotoxicity of juglone is markedly increased by ascorbate. Black-Right-Pointing-Pointer T24 cell death by oxidative stress is necrosis-like. Black-Right-Pointing-Pointer Redox cycling by juglone/ascorbate inhibits cell proliferation. Black-Right-Pointing-Pointer Cellular migration is impaired by juglone/ascorbate. -- Abstract: The effects of juglone on T24 cells were assessed in the presence and absence of ascorbate. The EC{sub 50} value for juglone at 24 h decreased from 28.5 {mu}M to 6.3 {mu}M in the presence of ascorbate. In juglone-treated cells, ascorbate increased ROS formation (4-fold) and depleted GSH (65%). N-acetylcysteine or catalase restricted the juglone/ascorbate-mediated effects, highlighting the role of oxidative stress in juglone cytotoxicity. Juglone alone or associated with ascorbate did not cause caspase-3 activation or PARP cleavage, suggesting necrosis-like cell death. DNA damage and the mild ER stress caused by juglone were both enhanced by ascorbate. In cells treated with juglone (1-5 {mu}M), a concentration-dependent decrease in cell proliferation was observed. Ascorbate did not impair cell proliferation but its association with juglone led to a clonogenic death state. The motility of ascorbate-treated cells was not affected. Juglone slightly restricted motility, but cells lost their ability to migrate most noticeably when treated with juglone plus ascorbate. We postulate that juglone kills cells by a necrosis-like mechanism inhibiting cell proliferation and the motility of T24 cells. These effects are enhanced in the presence of ascorbate.

Nucleotide sequences of two genomic DNAs encoding peroxidase of Arabidopsis thaliana.

Science.gov (United States)

Intapruk, C; Higashimura, N; Yamamoto, K; Okada, N; Shinmyo, A; Takano, M

1991-02-15

The peroxidase (EC 1.11.1.7)-encoding gene of Arabidopsis thaliana was screened from a genomic library using a cDNA encoding a neutral isozyme of horseradish, Armoracia rusticana, peroxidase (HRP) as a probe, and two positive clones were isolated. From the comparison with the sequences of the HRP-encoding genes, we concluded that two clones contained peroxidase-encoding genes, and they were named prxCa and prxEa. Both genes consisted of four exons and three introns; the introns had consensus nucleotides, GT and AG, at the 5' and 3' ends, respectively. The lengths of each putative exon of the prxEa gene were the same as those of the HRP-basic-isozyme-encoding gene, prxC3, and coded for 349 amino acids (aa) with a sequence homology of 89% to that encoded by prxC3. The prxCa gene was very close to the HRP-neutral-isozyme-encoding gene, prxC1b, and coded for 354 aa with 91% homology to that encoded by prxC1b. The aa sequence homology was 64% between the two peroxidases encoded by prxCa and prxEa.

Strand displacement activated peroxidase activity of hemin for fluorescent DNA sensing.

Science.gov (United States)

Wang, Quanbo; Xu, Nan; Gui, Zhen; Lei, Jianping; Ju, Huangxian; Yan, Feng

2015-10-07

To efficiently regulate the catalytic activity of the peroxidase mimic hemin, this work designs a double-stranded DNA probe containing an intermolecular dimer of hemin, whose peroxidase activity can be activated by a DNA strand displacement reaction. The double-stranded probe is prepared by annealing two strands of hemin labelled DNA oligonucleotides. Using the fluorescent oxidation product of tyramine by H2O2 as a tracing molecule, the low peroxidase activity of the hemin dimer ensures a low fluorescence background. The strand displacement reaction of the target DNA dissociates the hemin dimer and thus significantly increases the catalytic activity of hemin to produce a large amount of dityramine for fluorescence signal readout. Based on the strand displacement regulated peroxidase activity, a simple and sensitive homogeneous fluorescent DNA sensing method is proposed. The detection can conveniently be carried out in a 96-well plate within 20 min with a detection limit of 0.18 nM. This method shows high specificity, which can effectively distinguish single-base mismatched DNA from perfectly matched target DNA. The DNA strand displacement regulated catalytic activity of hemin has promising application in the determination of various DNA analytes.

Effect of 10% sodium ascorbate on Streptococcus mutans ...

African Journals Online (AJOL)

USER

2010-08-16

Aug 16, 2010 ... After sterilization of the intact enamel surfaces with UV light, the specimens .... the bleaching agent and sodium ascorbate has led to a maximum amount of .... Radcliffe CE, Lamp R, Blinkhorn AS, Drucker DB (2003). Effect of.

Thermal degradation kinetics of ascorbic acid, thiamine and riboflavin in rosehip (Rosa canina L nectar

Directory of Open Access Journals (Sweden)

Çetin KADAKAL

2017-10-01

Full Text Available Abstract In this paper, the loss of L-ascorbic acid, thiamine and riboflavin in rosehip nectar with the heating periods (0, 5, 10, 15, 20 and 30 min at temperatures ranging from 70 to 95 °C is analyzed and experimental results are presented. Firstly, dried rosehip fruits were processed to rosehip nectar and then thermal treatment is performed. Liquid chromatographic (HPLC method was used for the analysis of the contents of L-ascorbic acid, thiamine and riboflavin and examined compounds are thoroughly separated within 25 min. During thermal processing, degradation of L-ascorbic acid, thiamine and riboflavin in rosehip nectar were fitted to a first-order reaction kinetic model. Arrhenius relationship was used for the description of temperature dependence of reaction. Activation energies for L-ascorbic acid, thiamine and riboflavin between 70 to 95 ºC were found to be 55.30, 36.38 and 37.15 kJ/mol, respectively. To the best of the author’s knowledge, due to lack of study on the thermal degradation of L-ascorbic acid, thiamine and riboflavin in rosehip nectar, this manuscript will be the first reported study to enable future analysis.

Sequential injection redox or acid-base titration for determination of ascorbic acid or acetic acid.

Science.gov (United States)

Lenghor, Narong; Jakmunee, Jaroon; Vilen, Michael; Sara, Rolf; Christian, Gary D; Grudpan, Kate

2002-12-06

Two sequential injection titration systems with spectrophotometric detection have been developed. The first system for determination of ascorbic acid was based on redox reaction between ascorbic acid and permanganate in an acidic medium and lead to a decrease in color intensity of permanganate, monitored at 525 nm. A linear dependence of peak area obtained with ascorbic acid concentration up to 1200 mg l(-1) was achieved. The relative standard deviation for 11 replicate determinations of 400 mg l(-1) ascorbic acid was 2.9%. The second system, for acetic acid determination, was based on acid-base titration of acetic acid with sodium hydroxide using phenolphthalein as an indicator. The decrease in color intensity of the indicator was proportional to the acid content. A linear calibration graph in the range of 2-8% w v(-1) of acetic acid with a relative standard deviation of 4.8% (5.0% w v(-1) acetic acid, n=11) was obtained. Sample throughputs of 60 h(-1) were achieved for both systems. The systems were successfully applied for the assays of ascorbic acid in vitamin C tablets and acetic acid content in vinegars, respectively.

Calorimetric studies of the thermal denaturation of cytochrome c peroxidase

International Nuclear Information System (INIS)

Kresheck, G.C.; Erman, J.E.

1988-01-01

Two endotherms are observed by differential scanning calorimetry during the thermal denaturation of cytochrome c peroxidase at pH 7.0. The transition midpoint temperatures (t/sub m/) were 43.9 +- 1.4 and 63.3 +- 1.6 0 C, independent of concentration. The two endotherms were observed at all pH values between 4 and 8, with the transition temperatures varying with pH. Precipitation was observed between pH 4 and 6, and only qualitative data are presented for this region. The thermal unfolding of cytochrome c peroxidase was sensitive to the presence and ligation state of the heme. Only a single endotherm was observed for the unfolding of the apoprotein, and this transition was similar to the high-temperature transition in the holoenzyme. Addition of KCN to the holoenzyme increases the midpoint of the high-temperature transition whereas the low-temperature transition was increased upon addition of KF. Binding of the natural substrate ferricytochrome c to the enzyme increases the low-temperature transition by 4.8 +- 1.3 0 C but has no effect on the high-temperature transition at pH 7. The presence of cytochrome c peroxidase decreases the stability of cytochrome c, and both proteins appear to unfold simultaneously. The results are discussed in terms of the two domains evident in the X-ray crystallographic structure of cytochrome c peroxidase

Structure-activity relationships and molecular docking of thirteen synthesized flavonoids as horseradish peroxidase inhibitors.

Science.gov (United States)

Mahfoudi, Reguia; Djeridane, Amar; Benarous, Khedidja; Gaydou, Emile M; Yousfi, Mohamed

2017-10-01

For the first time, the structure-activity relationships of thirteen synthesized flavonoids have been investigated by evaluating their ability to modulate horseradish peroxidase (HRP) catalytic activity. Indeed, a modified spectrophotometrically method was carried out and optimized using 4-methylcatechol (4-MC) as peroxidase co-substrate. The results show that these flavonoids exhibit a great capacity to inhibit peroxidase with Ki values ranged from 0.14±0.01 to 65±0.04mM. Molecular docking has been achieved using Auto Dock Vina program to discuss the nature of interactions and the mechanism of inhibition. According to the docking results, all the flavonoids have shown great binding affinity to peroxidase. These molecular modeling studies suggested that pyran-4-one cycle acts as an inhibition key for peroxidase. Therefore, potent peroxidase inhibitors are flavonoids with these structural requirements: the presence of the hydroxyl (OH) group in 7, 5 and 4' positions and the absence of the methoxy (O-CH 3 ) group. Apigenin contributed better in HRP inhibitory activity. The present study has shown that the studied flavonoids could be promising HRP inhibitors, which can help in developing new molecules to control thyroid diseases. Copyright © 2017 Elsevier Inc. All rights reserved.

Peroxidase activity in Raphanus sativus and its relationship with soil heavy metals

International Nuclear Information System (INIS)

Alipour, H.; Zare Myvan, H.; Sharifi, M.

2009-01-01

Today heavy metals are important environmental pollutants which generated from human activities and are one of the most important environmental stresses that cause molecular damages to plants through reactive oxygen species formation such as H2O2. Heavy metals are absorbed and accumulated by plants thus are absorbed by human bodies through the food chain. Raphanus sativus is a herbaceous plant within the Brassicaceae family that has different varieties and is used as a food plant in different parts of Iran. Peroxidase is one of the most important enzyme in oxidoreductase super family that can metabolize H2O2. In this research we studied some growth parameters, peroxidase activity and their relationships with heavy metal content and other soil factors in three different populations of radish collected from Sari, Semnan and south of Tehran. After harvesting the plants shoots and roots Peroxidase activity was assayed spectrophotometrically at 470 nm. Our results showed total heavy metal content of shomal 3 station soil and radish plants was higher than other stations, so plants collected from this station had lowest root and shoot lengths, fresh weights, dry weights, protein content and leaf collrophyll content. The peroxidase activity in both leaves and roots of these plants was higher than plants of other stations Therefore our results showed that with increasing heavy metal concentrations in soils peroxidase activity increased.

Changes in photosynthetic performance and antioxidative strategies during maturation of Norway maple (Acer platanoides L.) leaves.

Science.gov (United States)

Lepeduš, Hrvoje; Gaća, Vlatka; Viljevac, Marija; Kovač, Spomenka; Fulgosi, Hrvoje; Simić, Domagoj; Jurković, Vlatka; Cesar, Vera

2011-04-01

Different structural and functional changes take place during leaf development. Since some of them are highly connected to oxidative metabolism, regulation of reactive oxygen species (ROS) abundance is required. Most of the reactive oxygen species ROS in plant cells are produced in chloroplasts as a result of highly energetic reactions of photosynthesis. The aim of our study was to examine the changes in concentration of oxidative stress parameters (TBARS - thiobarbituric acid-reacting substances and protein carbonyls) as well as antioxidative strategies during development of maple (Acer platanoides L.) leaves in the light of their enhanced photosynthetic performance. We reveal that biogenesis of the photosynthetic apparatus during maple leaf maturation corresponded with oxidative damage of lipids, but not proteins. In addition, antioxidative responses in young leaves differed from that in older leaves. Young leaves had high values of non-photochemical quenching (NPQ) and catalase (CAT, EC 1.11.1.6) activity which declined during the maturation process. Developing leaves were characterized by an increase in TBARS level, the content of non-enzymatic antioxidants as well as ascorbate peroxidase activity (APX, EC 1.11.1.11), while the content of protein carbonyls decreased with leaf maturation. Fully developed leaves had the highest lipid peroxidation level accompanied by a maximum in ascorbic acid content and superoxide dismutase activity (SOD, EC1.15.1.1). These observations imply completely different antioxidative strategies during leaf maturation enabling them to perform their basic function. Copyright © 2011 Elsevier Masson SAS. All rights reserved.

Alleviatory activities in mycorrhizal tobacco plants subjected to increasing chloride in irrigation water

Directory of Open Access Journals (Sweden)

Ali Reza Safahani Langeroodi

2017-03-01

Full Text Available The effects of presence and absence of arbuscular mycorrhizal (AM+ and AM- fungus (AMF Glomus intraradices on agronomic and chemical characteristics of field-grown tobacco (Nicotiana tabacum L. Virginia type (cv. K-326 plants exposed to varying concentrations of chloride 10, 40, 70 and 100 mg Cl L–1 (C1-C4 were studied over two growing seasons (2012-2013. Mycorrhizal plants had significantly higher uptake of nutrients in shoots and number of leaves regardless of intensities of chloride stress. The cured leaves yields of AM+ plants under C2-C4 chloride stressed conditions were higher than AM- plants. Leaf chloride content increased in line with the increase of chloride level, while AMF colonised plants maintained low Cl content. AM+ plants produced tobacco leaves that contained significantly higher quantities of nicotine than AM- plants. AM inoculation ameliorated the chloride stress to some extent. Antioxidant enzymes like superoxide dismutase, catalase, ascorbate peroxidase, and glutathione reductase as well as non-enzymatic antioxidants (ascorbic acid and glutathione also exhibited great variation with chloride treatment. Chloride stress caused great alterations in the endogenous levels of growth hormones with abscisic acid showing increment. AMF inoculated plants maintained higher levels of growth hormones and also allayed the negative impact of chloride. The level of 40 mg L–1 in combination with arbuscular mycorrhizal can be considered as the acceptable threshold to avoid adverse effects on Virginia tobacco.

Boron excess affects photosynthesis and antioxidant apparatus of greenhouse Cucurbita pepo and Cucumis sativus.

Science.gov (United States)

Landi, Marco; Remorini, Damiano; Pardossi, Alberto; Guidi, Lucia

2013-11-01

This study aimed to evaluate the behavior of zucchini (Cucurbita pepo L.) and cucumber (Cucumis sativus L.) under boron (B) excess. Plants were grown under greenhouse conditions in a sandy soil-peat mixture using a nutrient solution containing 0.2 (control), 10 and 20 mg L(-1) B. Visible symptoms were quantified and leaf B accumulation, gas exchanges, chlorophyll (Chl) a fluorescence, malondialdehyde by-products and antioxidants were investigated 20 days after the beginning of the treatments. Boron toxicity induced oxidative load and leaf necrotic burns coupled with the reduction of leaf growth and biomass accumulation in both species. Boron excess resulted in a decrease of Chl a/b ratio, potential (Fv/Fm) and actual (ΦPSII) PSII quantum efficiency, photosynthetic rate (Pn), stomatal conductance (gs), and transpiration (E) as well. A general stimulation of the antioxidant enzymes ascorbate peroxidase, catalase and superoxide dismutase was observed, and a significant increase in the oxidized form of ascorbate and glutathione was evidenced for treated plants of both species. A difference between the two species was observed: C. pepo appeared to be more sensitive to B stress being damaged at all B concentration. C. sativus grown at 10 mg L(-1) B in nutrient solution showed some down-regulated mechanisms, i.e. increase in Chl b content and a good photochemical PSII efficiency as well as a higher amount of constitutive antioxidant molecules, that, however, are not sufficient to contrast the negative effects of B.

Investigation of L(+)-Ascorbic Acid with Raman Spectroscopy in Visible and UV Light

DEFF Research Database (Denmark)

Berg, Rolf W.

2015-01-01

Abstract: Raman spectroscopy investigations of l(+)-ascorbic acid and its mono- and di-deprotonated anions (AH(-) and A(2-)) are reviewed and new measurements reported with several wavelengths, 229, 244, 266, 488, and 532nm. Results are interpreted, assisted by new DFT/B3LYP quantum chemical calc......). Relatively weak preresonance enhancement was seen for A(2-) when excitation was done with 229nm UV light, allowing water bands to become observable as for normal visible light Raman spectra....... calculations with 6-311++G(d,p) basis sets for several conformations of ascorbic acid and the anions. Raman spectra were measured during titration with NaOH base in an oxygen-poor environment to avoid fluorescence when solutions were alkaline. The ultraviolet (UV) absorption band for ascorbic acid in aqueous......cm(-1). Finally, for the ascorbate di-anion, absorption was found at similar to 298.4nm with molar absorptivity of similar to 7,000 L mol(-1) cm(-1) and below similar to 220nm. With UV light (244 and 266nm), strongly basic solutions gave pronounced Raman resonance enhancement at similar to 1556cm(-1...

Effect of temperature variations during cooking and storage on ascorbic acid contents of vegetables: a comparative study

International Nuclear Information System (INIS)

Zaman, W.U.; Akram, M.; Rehman, R.

2013-01-01

Summary: Vegetables are generally boiled for cooking or stored in refrigerators. This results in loss of their nutritional values. Ascorbic acid is one of the important nutrients for human health. In this study, Ascorbic acid (vitamin-C) content of various vegetables of Pakistan was determined, and effect of boiling and freezing were compared with natural Ascorbic acid contents by HPLC. The maximum concentration of Ascorbic acid was found in green chilli: i.e. 105 mg /100 g in fresh state; while in boiled and frozen state its concentration is comparatively less: i.e. 85 and 92 mg/100 g respectively. The other vegetables like: cabbage, to mato, turnip, potato, spinach, onion, garlic, green pea, green beans and cauliflower contained greater amount of Ascorbic acid in their fresh state i.e. 30, 20, 25.3, 20, 30, 24.3, 31, 28.5, 30, 42 mg/100 g as compared to frozen (23.4, 13, 23.6, 15, 23.4, 14.1,25, 26.5, 27.0, and 39 mg/100g respectively) and boiled state (11.6, 9.3, 22.5, 10.0, 20.3, 13.1, 23, 25.2 and 35 mg /100g respectively). The minimum amount of Ascorbic acid was found in boiled state of carrot and lettuce: i.e. 4.0 mg/100 g. These results showed that freezing or boiling of vegetables causes significant lo ss of available Ascorbic acid contents, especially boiling. (author)

Water stress induces overexpression of superoxide dismutases that ...

African Journals Online (AJOL)

Water stress is known to induce active oxygen species in plants. The accumulation of these harmful species must be prevented by plants as rapidly as possible to maintain growth and productivity. The aim of this study was to determine the effect of water stress on superoxide dismutase isozymes (SOD, EC 1.15.1.1.) in two ...

Ascorbic acid supplementation partially prevents the delayed reproductive development in juvenile male rats exposed to rosuvastatin since prepuberty.

Science.gov (United States)

Leite, Gabriel Adan Araújo; Figueiredo, Thamiris Moreira; Sanabria, Marciana; Dias, Ana Flávia Mota Gonçalves; Silva, Patrícia Villela E; Martins Junior, Airton da Cunha; Barbosa Junior, Fernando; Kempinas, Wilma De Grava

2017-10-01

Dyslipidemias are occurring earlier in the population due to the increase of obesity and bad eating habits. Rosuvastatin inhibits the enzyme HMG-CoA reductase, decreasing total cholesterol. Ascorbic acid is an important antioxidant compound for male reproductive system. This study aimed to evaluate whether ascorbic acid supplementation may prevent the reproductive damage provoked by rosuvastatin administration at prepuberty. Male pups were distributed into six experimental groups that received saline solution 0.9%, 3 or 10mg/kg/day of rosuvastatin, 150mg/day of ascorbic acid, or 150mg/day of ascorbic acid associated with 3 or 10mg/kg/day of rosuvastatin from post-natal day (PND) 23 until PND53. Rosuvastatin-treated groups showed delayed puberty installation, androgen depletion and impairment on testicular and epididymal morphology. Ascorbic acid partially prevented these reproductive damages. In conclusion, rosuvastatin exposure is a probable risk to reproductive development and ascorbic acid supplementation may be useful to prevent the reproductive impairment of rosuvastatin exposure. Copyright © 2017 Elsevier Inc. All rights reserved.

Polyphenol oxidase and peroxidase in different sugarcane cultivars, in Presidente Prudente region; Polifenoloxidases e peroxidase em diferentes variedades de cana-de-acucar na regiao de Presidente Prudente

Energy Technology Data Exchange (ETDEWEB)

Marques, Tadeu A.; Gomes, Danilo B.; Marques, Patricia A.A.; Alves, Vagner C. [Universidade do Oeste Paulista (UNOESTE), Presidente Prudente, SP (Brazil). Curso de Agronomia], Emails: tmarques@unoeste.br, pmarques@unoeste.br, vagner@unoeste.br

2009-07-01

The objective in present work was compare three sugarcane cultivars (RB 72-454, RB 86-7515, IAC 86-2480), evaluating the content of polyphenoloxidase and peroxidase. These determinations had aimed at to detect possible differences between varieties thus and being to differentiate them with regard to the products most interesting to be elaborated, ethanol production or sugar production. The varieties had presented differences of behavior for studied enzymes. The activity of polyphenoloxidase was superior the activity of peroxidase. The enzyme peroxidase was presented in bigger indices in the dry and cold periods. The enzyme polyphenoloxidase was presented well changeable, but with strong trend of bigger values in the rainy periods. It can be said that distinct periods for the best use of the varieties in the sugar production or alcohol exist. (author)

Role of ascorbic acid on tyrosine hydroxylase activity in the adrenal gland of guinea pig

International Nuclear Information System (INIS)

Nakashima, Yoko; Sanada, Hiroo; Suzue, Ryokuero; Kawada, Shoji

1976-01-01

The decrease of tyrosine hydroxylase activity in adrenal homogenate in scurvy was recovered after the administration of ascorbic acid. The causes of the increase in the enzyme activity after the administration of ascorbic acid have been studied. 1. No significant elevation in the enzyme activity was observed after the administration of reserpine to the scorbutic guinea pig. 2. A dose of metal chelating agent, α, α'-dipyridyl, prevented the ascorbic acid-induced or reserpine-induced increase in enzyme activity in the scorbutic and the nonscorbutic guinea pigs, respectively. 3. Tyrosine hydroxylase activity was partially recovered by the administration of FeSO 4 to the scorbutic guinea pig. From these results, it became clear that the induction of tyrosine hydroxylase which was not observed in scurvy was due to the deficiency of Fe 2+ . These results suggested that ascorbic acid affected the induction of this enzyme via Fe 2+ . (auth.)

Spectrophotometric determination of copper with ascorbic acid

International Nuclear Information System (INIS)

Majeed, A.; Mustafa, M.M.; Asma, R.N.; Sareecha, N.

1996-01-01

Copper has been determined spectrophotometrically by using ascorbic acid as a chromagenic reagent. The complex formed in basic medium is measured for its absorbance at 340 n.m. Interference for 23 cations and 9 anions has also been checked. Effect of pH, time, temperature, ammonia, reagent concentration and interferents has been report. (author)

Spectrophotometric determination of copper with ascorbic acid

Energy Technology Data Exchange (ETDEWEB)

Majeed, A; Mustafa, M M; Asma, R N; Sareecha, N [Islamia Univ., Bahawalpur (Pakistan). Chemistry Dept.

1996-06-01

Copper has been determined spectrophotometrically by using ascorbic acid as a chromagenic reagent. The complex formed in basic medium is measured for its absorbance at 340 n.m. Interference for 23 cations and 9 anions has also been checked. Effect of pH, time, temperature, ammonia, reagent concentration and interferents has been report. (author).

Comparison of radioprotective effects of caffeine and ascorbic acid in male mice

Energy Technology Data Exchange (ETDEWEB)

Kim, Jin Kyu; Kim, Ji Hyang; Lee, Byoung Hun [KAERI, Taejon (Korea, Republic of); Yoon, Yong Dal [Hanyang Univ., Seoul (Korea, Republic of)

2003-04-01

The oxygen effect in radiation biology is well known. Since oxygen enhances radiation-induced biological damage, antioxidants should be radioprotectors. Ascorbic acid (vitamin C) or caffeine is an essential component in the diet of humans and a small range of other mammals. Radioprotective effects of vitamin C have been demonstrated in certain cells and animals, which would result from scavenging free radicals. Caffeine is the main psychoactive ingredient of coffee, tea, even coke with a high frequency of concurrent use in humans. Caffeine has been recently reported as a scavenger of hydroxyl radical in millimolar levels and a potently radioprotector in a chronically exposed rodent. This study investigates functional radioprotection of caffeine and ascorbic acid against gamma irradiation in male mice. Eight-week-old male C57BL/6N mice were irradiated with 6.5 Gy. A caffeine treated group was administered with 80 mg/kg body weight by i.p injection, a single exposure 1 hour before irradiation. Ascorbic acid was administered 330 mg/liter in drinking water through all the experimental period. The remaining mice were kept as sham controls. After collecting a serum from the experimental mice 6 hr after irradiation, qualitative analysis of testosterone was performed by means of radioimmunoassay (RIA). For histological investigation, testes were removed 1 week after irradiation and fixed in NBF. Fixed testes were processed for paraffin sections and stained by H-E. The circulating testosterone significantly decreased in all irradiated groups. The harmful effect of radiation on the body and organ weight and the appearance of semiferous tubules were significantly improved in the caffeine - or ascorbic acid-treated group. In conclusion, caffeine and ascorbic acid protected spermatogenesis from impairment against gamma radiation, acting as a radioprotector.

Comparison of radioprotective effects of caffeine and ascorbic acid in male mice

International Nuclear Information System (INIS)

Kim, Jin Kyu; Kim, Ji Hyang; Lee, Byoung Hun; Yoon, Yong Dal

2003-01-01

The oxygen effect in radiation biology is well known. Since oxygen enhances radiation-induced biological damage, antioxidants should be radioprotectors. Ascorbic acid (vitamin C) or caffeine is an essential component in the diet of humans and a small range of other mammals. Radioprotective effects of vitamin C have been demonstrated in certain cells and animals, which would result from scavenging free radicals. Caffeine is the main psychoactive ingredient of coffee, tea, even coke with a high frequency of concurrent use in humans. Caffeine has been recently reported as a scavenger of hydroxyl radical in millimolar levels and a potently radioprotector in a chronically exposed rodent. This study investigates functional radioprotection of caffeine and ascorbic acid against gamma irradiation in male mice. Eight-week-old male C57BL/6N mice were irradiated with 6.5 Gy. A caffeine treated group was administered with 80 mg/kg body weight by i.p injection, a single exposure 1 hour before irradiation. Ascorbic acid was administered 330 mg/liter in drinking water through all the experimental period. The remaining mice were kept as sham controls. After collecting a serum from the experimental mice 6 hr after irradiation, qualitative analysis of testosterone was performed by means of radioimmunoassay (RIA). For histological investigation, testes were removed 1 week after irradiation and fixed in NBF. Fixed testes were processed for paraffin sections and stained by H-E. The circulating testosterone significantly decreased in all irradiated groups. The harmful effect of radiation on the body and organ weight and the appearance of semiferous tubules were significantly improved in the caffeine - or ascorbic acid-treated group. In conclusion, caffeine and ascorbic acid protected spermatogenesis from impairment against gamma radiation, acting as a radioprotector

Synthesis of colloidal silver nanoparticle clusters and their application in ascorbic acid detection by SERS.

Science.gov (United States)

Cholula-Díaz, Jorge L; Lomelí-Marroquín, Diana; Pramanick, Bidhan; Nieto-Argüello, Alfonso; Cantú-Castillo, Luis A; Hwang, Hyundoo

2018-03-01

Ascorbic acid (vitamin C) has an essential role in the human body mainly due to its antioxidant function. In this work, metallic silver nanoparticle (AgNP) colloids were used in SERS experiments to detect ascorbic acid in aqueous solution. The AgNPs were synthesized by a green method using potato starch as reducing and stabilizing agent, and water as the solvent. The optical properties of the yellowish as-synthesized silver colloids were characterized by UV-vis spectroscopy, in which besides a typical band at 410 nm related to the localized surface plasmon resonance of the silver nanoparticles, a shoulder band around 500 nm, due to silver nanoparticle cluster formation, is presented when relatively higher concentrations of starch are used in the synthesis. These starch-capped silver nanoparticles show an intrinsic Raman peak at 1386 cm -1 assigned to deformation modes of the starch structure. The increase of the intensity of the SERS peak at 1386 cm -1 with an increase in the concentration of the ascorbic acid is related to a decrease of the gap between dimers and trimers of the silver nanoparticle clusters produced by the presence of ascorbic acid in the colloid. The limit of detection of this technique for ascorbic acid is 0.02 mM with a measurement concentration range of 0.02-10 mM, which is relevant for the application of this method for detecting ascorbic acid in biological specimen. Copyright © 2017 Elsevier B.V. All rights reserved.

The comparison of techniques and methods for L-ascorbic acid determination in the fruits

Directory of Open Access Journals (Sweden)

Cvetković Biljana R.

2012-01-01

Full Text Available Vitamin C is an essential vitamin for human nutrition; with the L-ascorbic acid (AA being the active form of vitamin C. Hence, determination of the L-ascorbic acid in the natural and processed foods is very important. In the past, plenty of methods based on the reversible redox reaction of AA oxidation/DHA reduction were developed. Because of L-ascorbic acid instability in aqueous solutions, it is useful to analyze various types of extraction. The aim of this study is to compare three different methods and three different extractants for the L-ascorbic acid determination. Fruits (kiwi, lemon, orange, and grapefruit were purchased from a local market. The L-ascorbic acid in these four samples was determined by the three different methods: the AOAC, the HPLC method with three different types of extractions, and the colorimetric method using ascorbate-oxidase. For the HPLC measurements, one part of the fruits was extracted with distilled water, the second with potassium hydrogen phosphate, and the third with 3% meta-phosphoric acid (MPA in 8% acetic acid. The HPLC measurements of each sample were repeated three times, the AOAC titration was repeated five times, and in the calorimetric method three measurements were performed. The results were statistically evaluated related to sample basis. Statistical analysis shows that there is a significant difference between the results for all three methods of extraction for all samples, except for the grapefruit sample where no significant difference was observed between the results obtained after the buffer extraction (E2 and the metaphosphoric acid in acetic acid extraction (E3. Discriminative analysis for the HPLC determinations proves that there is a clear difference and defined border between the samples in relation to the methods of extraction during the HPLC determination.

Redox regulation of peroxiredoxin and proteinases by ascorbate and thiols during pea root nodule senescence.

Science.gov (United States)

Groten, Karin; Dutilleul, Christelle; van Heerden, Philippus D R; Vanacker, Hélène; Bernard, Stéphanie; Finkemeier, Iris; Dietz, Karl-Josef; Foyer, Christine H

2006-02-20

Redox factors contributing to nodule senescence were studied in pea. The abundance of the nodule cytosolic peroxiredoxin but not the mitochondrial peroxiredoxin protein was modulated by ascorbate. In contrast to redox-active antioxidants such as ascorbate and cytosolic peroxiredoxin that decreased during nodule development, maximal extractable nodule proteinase activity increased progressively as the nodules aged. Cathepsin-like activities were constant throughout development but serine and cysteine proteinase activities increased during senescence. Senescence-induced cysteine proteinase activity was inhibited by cysteine, dithiotreitol, or E-64. Senescence-dependent decreases in redox-active factors, particularly ascorbate and peroxiredoxin favour decreased redox-mediated inactivation of cysteine proteinases.

Properties of catalase-peroxidase lacking its C-terminal domain

International Nuclear Information System (INIS)

Baker, Ruletha D.; Cook, Carma O.; Goodwin, Douglas C.

2004-01-01

Catalase-peroxidases have a two-domain structure. The N-terminal domain contains the bifunctional active site, but the function of the C-terminal domain is unknown. We produced catalase-peroxidase containing only its N-terminal domain (KatG Nterm ). Removal of the C-terminal domain did not result in unexpected changes in secondary structure as evaluated by CD, but KatG Nterm had neither catalase nor peroxidase activity. Partial recovery of both activities was achieved by incubating KatG Nterm with the separately expressed and isolated KatG C-terminal domain. Spectroscopic measurements revealed a shift in heme environment from a mixture of high-spin species (wtKatG) to exclusively hexacoordinate, low-spin (KatG Nterm ). Moreover, a >1000-fold lower k on for CN - binding was observed for KatG Nterm . EPR spectra for KatG Nterm and the results of site-specific substitution of active site histidines suggested that the distal histidine was the sixth ligand. Thus, one important role for the C-terminal domain may be to support the architecture of the active site, preventing heme ligation by this catalytically essential residue

STRAWBERRY (FRAGARIA X ANANASSA DUCH LEAF ANTIOXIDATIVE RESPONSE TO BIOSTIMULATORS AND REDUCED FERTILIZATION WITH N AND K

Directory of Open Access Journals (Sweden)

Marija Špoljarević

2010-06-01

Full Text Available Strawberry cultivar Elsanta was grown in peat based substrate in a green house. Full dose and 50% reduced nitrogen and potassium fertilization were applied during fruit bearing period in spring, along with biostimulators Viva®, Megafol® and their combination. The specific activities of guaiacol peroxidase (GPXs; EC 1.11.1.7, catalase (CATs; EC 1.11.1.6, ascorbate peroxidase (APXs; EC 1.11.1.11 and glutathione reductase (GRs; EC 1.6.4.2 in strawberry leaf were stimulated by biostimulators and reduced fertilization. The strongest link seen here was between the enzymes of ascorbate-glutathione cycle (APXs and GRs, which were positively related to trifoliate leaf fresh mass (TLFM. The highest TLFM was observed in Megafol® treated plants.

Ascorbic acid, β-carotene, total phenolic compound and ...

African Journals Online (AJOL)

A two year study at Alexandria University compared ascorbic acid, β-carotene, total phenolic compound, nitrite content and microbiological quality of orange and strawberry fruits grown under organic and conventional management techniques to see if producers concerns are valid. Organically grown oranges and ...

21 CFR 172.315 - Nicotinamide-ascorbic acid complex.

Science.gov (United States)

2010-04-01

... 172.315 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) FOOD ADDITIVES PERMITTED FOR DIRECT ADDITION TO FOOD FOR HUMAN CONSUMPTION Special Dietary and Nutritional Additives § 172.315 Nicotinamide-ascorbic acid complex...

Occurrence and properties of Petunia peroxidase a

NARCIS (Netherlands)

Hendriks, T.

1989-01-01

Peroxidases are probably the most extensively studied enzymes in higher plants. Various isoenzymes occur as soluble proteins in the apoplast and in the vacuole, or are bound to membranes and cell walls. Their occurrence is often organ-specific and developmentally controlled, and there is

Apoplastic ascorbate contributes to the differential ozone sensitivity in two varieties of winter wheat under fully open-air field conditions

International Nuclear Information System (INIS)

Feng Zhaozhong; Pang Jing; Nouchi, Isamu; Kobayashi, Kazuhiko; Yamakawa, Takashi; Zhu Jianguo

2010-01-01

We studied leaf apoplastic ascorbates in relation to ozone (O 3 ) sensitivity in two winter wheat (Triticum aestivum L.) varieties: Yangfumai 2 (Y2) and Yangmai 16 (Y16). The plants were exposed to elevated O 3 concentration 27% higher than the ambient O 3 concentration in a fully open-air field from tillering stage until final maturity. The less sensitive variety Y16 had higher concentration of reduced ascorbate in the apoplast and leaf tissue by 33.5% and 12.0%, respectively, than those in the more sensitive variety Y2, whereas no varietal difference was detected in the decline of reduced ascorbate concentration in response to elevated O 3 . No effects of O 3 or variety were detected in either oxidized ascorbate or the redox state of ascorbate in the apoplast and leaf tissue. The lower ascorbate concentrations in both apoplast and leaf tissue should have contributed to the higher O 3 sensitivity in variety Y2. - Apoplastic ascorbate contributes to varietal difference in wheat tolerance to O 3 .

Antioxidant effects of nerolidol in mice hippocampus after open field test.

Science.gov (United States)

Nogueira Neto, José Damasceno; de Almeida, Antonia Amanda Cardoso; da Silva Oliveira, Johanssy; Dos Santos, Pauline Sousa; de Sousa, Damião Pergentino; de Freitas, Rivelilson Mendes

2013-09-01

The aim of this study was to evaluate the neuroprotective effects of nerolidol in mice hippocampus against oxidative stress in neuronal cells compared to ascorbic acid (positive control) as well as evaluated the nerolidol sedative effects by open field test compared to diazepam (positive control). Thirty minutes prior to behavioral observation on open field test, mice were intraperitoneally treated with vehicle, nerolidol (25, 50 and 75 mg/kg), diazepam (1 mg/kg) or ascorbic acid (250 mg/kg). To clarify the action mechanism of of nerolidol on oxidative stress in animals subjected to the open field test, Western blot analysis of Mn-superoxide dismutase and catalase in mice hippocampus were performed. In nerolidol group, there was a significant decrease in lipid peroxidation and nitrite levels when compared to negative control (vehicle). However, a significant increase was observed in superoxide dismutase and catalase activities in this group when compared to the other groups. Vehicle, diazepam, ascorbic acid and nerolidol groups did not affected Mn-superoxide dismutase, catalase mRNA or protein levels. Our findings strongly support the hypothesis that oxidative stress occurs in hippocampus. Nerolidol showed sedative effects in animals subjected to the open field test. Oxidative process plays a crucial role on neuronal pathological consequence, and implies that antioxidant effects could be achieved using this sesquiterpene.

Purification, characterization and stability of barley grain peroxidase BP1, a new type of plant peroxidase

DEFF Research Database (Denmark)

Rasmussen, Christine B; Henriksen, Anette; Abelskov, A. Katrine

1997-01-01

peroxidase isoenzyme C (HRP C). However, when measuring the specific activity of BP 1 at pH 4.0 in the presence of 1 mM CaCl2, the enzyme was as competent as HRP C at neutral pH towards a variety of substrates (mM mg(-1) min(-1)): coniferyl alcohol (930+/-48), caffeic acid (795+/-53), ABTS (2,2(1)-azino...

Changes in peroxidases associated with radiation-induced sprout inhibition in garlic (Allium sativum L.)

International Nuclear Information System (INIS)

Croci, C.A.; Curvetto, N.R.; Orioli, G.A.; Arguello, J.A.

1991-01-01

The effects of an acute dose of γ-rays (10 Gy) to post-dormant garlic cloves on inner sprout growth and changes in peroxidases and soluble proteins were evaluated up to 100 days of storage in darkness at 19±1 0 C and 42±2% relative humidity. Radiation-induced inhibition of sprout growth became evident after 25 days of treatment and was synchronous with a marked increase in peroxidase activity. Thin-layer isoelectric focusing revealed that radiation induced an increase in the number of anodic peroxidase isoenzymes at 100 days, suggesting modifications in the vascularization process. Neither the soluble protein content nor the protein pattern were affected by irradiation. These results are discussed in terms of a possible mediating effect of peroxidase on radiation-induced sprout inhibition in garlic. (author)

Changes in peroxidases associated with radiation-induced sprout inhibition in garlic (Allium sativum L. )

Energy Technology Data Exchange (ETDEWEB)

Croci, C.A.; Curvetto, N.R.; Orioli, G.A. (Universidad Nacional del Sur, Bahia Blanca (Argentina)); Arguello, J.A. (Universidad Nacional de Cordoba (Argentina). Dept. de Biologia Aplicada)

1991-02-01

The effects of an acute dose of {gamma}-rays (10 Gy) to post-dormant garlic cloves on inner sprout growth and changes in peroxidases and soluble proteins were evaluated up to 100 days of storage in darkness at 19+-1{sup 0}C and 42+-2% relative humidity. Radiation-induced inhibition of sprout growth became evident after 25 days of treatment and was synchronous with a marked increase in peroxidase activity. Thin-layer isoelectric focusing revealed that radiation induced an increase in the number of anodic peroxidase isoenzymes at 100 days, suggesting modifications in the vascularization process. Neither the soluble protein content nor the protein pattern were affected by irradiation. These results are discussed in terms of a possible mediating effect of peroxidase on radiation-induced sprout inhibition in garlic. (author).

Response of oxidative stress defense systems in rice (Oryza sativa) leaves with supplemental UV-B radiation

International Nuclear Information System (INIS)

Dai, Q.; Yan, B.; Huang, S.; Liu, X.; Peng, S.; Miranda, M.L.L.; Chavez, A.Q.; Vergara, B.S.; Olszyk, D.M.

1997-01-01

The impact of elevated ultraviolet-B radiation (UV-B, 280–320 nm) on membrane systems and lipid peroxidation, and possible involvement of active oxygen radicals was investigated in leaves of two UV-B susceptible rice cultivars (Oryza sativa L. cvs IR74 and Dular). Rice seedlings were grown in a greenhouse for 10 days and then treated with biologically effective UV-B (UV-B BE ) radiation for 28 days. Oxidative stress effects were evaluated by measuring superoxide anion (O 2 ) generation rate, hydrogen peroxide (H 2 O 2 ) content, malondialdehyde (MDA) concentration and relative electrolyte conductivity (EC) for IR74 and Dular at 0 (control), 6 or 13 kJ m −2 day −1 UV-B BE . Significant increases in these parameters were found in rice plants grown at 13 vs 0 kJ m −2 day −1 UV-B BE after 28 days; indicating that disruption of membrane systems may be an eventual reason for UV-B-induced injury in rice plants. There was a positive correlation between O 2 − generation and increases in EC or MDA in leaves. Activities of enzymatic and nonenzymatic free radical scavengers were measured for IR74 after 7, 14, 21 and 28 days of exposure to 13 or 0 UV-B BE to evaluate dynamics of these responses over time. Activities of catalase and superoxide dismutase (but not ascorbate peroxidase) and concentrations of ascorbic acid and glutathione were enhanced by 13 vs 0 UV-B BE after 14 days of UV-B exposure. Further exposure to 28 days of UV-B was associated with a decline in enzyme activities and ascorbic acid, but not glutathione. It is suggested that UV-B-induced injury may be associated with disturbance of active oxygen metabolism through the destruction and alteration of both enzymatic and nonenzymatic defense systems in rice. (author)

Exogenous 5-aminolevulenic acid promotes seed germination in Elymus nutans against oxidative damage induced by cold stress.

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Juanjuan Fu

Full Text Available The protective effects of 5-aminolevulenic acid (ALA on germination of Elymus nutans Griseb. seeds under cold stress were investigated. Seeds of E. nutans (Damxung, DX and Zhengdao, ZD were pre-soaked with various concentrations (0, 0.1, 0.5, 1, 5, 10 and 25 mg l(-1 of ALA for 24 h before germination under cold stress (5°C. Seeds of ZD were more susceptible to cold stress than DX seeds. Both seeds treated with ALA at low concentrations (0.1-1 mg l(-1 had higher final germination percentage (FGP and dry weight at 5°C than non-ALA-treated seeds, whereas exposure to higher ALA concentrations (5-25 mg l(-1 brought about a dose dependent decrease. The highest FGP and dry weight of germinating seeds were obtained from seeds pre-soaked with 1 mg l(-1 ALA. After 5 d of cold stress, pretreatment with ALA provided significant protection against cold stress in the germinating seeds, significantly enhancing seed respiration rate and ATP synthesis. ALA pre-treatment also increased reduced glutathione (GSH, ascorbic acid (AsA, total glutathione, and total ascorbate concentrations, and the activities of superoxide dismutase (SOD, catalase (CAT, ascorbate peroxidase (APX and glutathione reductase (GR, whereas decreased the contents of malondialdehyde (MDA and hydrogen peroxide (H2O2, and superoxide radical (O2•- release in both germinating seeds under cold stress. In addition, application of ALA increased H+-ATPase activity and endogenous ALA concentration compared with cold stress alone. Results indicate that ALA considered as an endogenous plant growth regulator could effectively protect E. nutans seeds from cold-induced oxidative damage during germination without any adverse effect.

EFFECT OF POLYPHENOLIC COMPLEX FROM WINE ON RATS ANTIOXIDANT ENZYMES ACTIVITY AT X-RAY IRRADIATION LOW DOSES

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U. V. Datsyuk

2014-04-01

Full Text Available It is shown that the consumption of natural polyphenolic complex from grape wine in drinking water in the daily dose 2.5 ± 1.1 mg polyphenols/kg body mass of rats during the 10 day before exposure to radiation leads to increased of superoxide dismutase and gluthathione reductase activities in peripheral blood on 24 and 48 hours after full body X-ray irradiation (30 cGy. The of catalase, gluthathione peroxidase activities and the of the reactive thiobarbituric acid substances content in total lysates of peripheral blood within 72 hours after exposure are comparable to those in control rats. Marked decreased of catalase and superoxide dismutase activities at 24, 48 and 24 hours, respectively, was observed after exposure to ionizing radiation and increased content of lipid peroxidation products in all above mentioned time points. The decreased of superoxide dismutase and gluthathione peroxidase activities in lysates of rats aorta at 48 hour and increased content of the reactive thiobarbituric acid substances during 72 hours after radiation exposure were observed. The consumption of polyphenolic complex from wine did not change the superoxide dismutase and catalase activities in lysates of aorta rats treated with ionizing radiation, whereas gluthathione reductase and gluthathione peroxidase activities was increased during 72 hours after radiation influence. The content of TBA reactive substances was significantly decreased in lysates of aorta rats that were exposed to radiation and polyphenols of grape wine, compared with those of animals that were exposed to radiation alone.

Green Synthesized Zinc Oxide (ZnO Nanoparticles Induce Oxidative Stress and DNA Damage in Lathyrus sativus L. Root Bioassay System

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Kamal K. Panda

2017-05-01

Full Text Available Zinc oxide nanoparticles (ZnONP-GS were synthesised from the precursor zinc acetate (Zn(CH3COO2 through the green route using the milky latex from milk weed (Calotropis gigantea L. R. Br by alkaline precipitation. Formation of the ZnONP-GS was monitored by UV-visible spectroscopy followed by characterization and confirmation by energy-dispersive X-ray spectroscopy (EDX, transmission electron microscopy (TEM, and X-ray diffraction (XRD. Both the ZnONP-GS and the commercially available ZnONP-S (Sigma-Aldrich and cationic Zn2+ from Zn(CH3COO2 were tested in a dose range of 0–100 mg·L−1 for their potency (i to induce oxidative stress as measured by the generation reactive oxygen species (ROS: O2•−, H2O2 and •OH, cell death, and lipid peroxidation; (ii to modulate the activities of antioxidant enzymes: catalase (CAT, superoxide dismutase (SOD, guaiacol peroxidase (GPX, and ascorbate peroxidase (APX; and (iii to cause DNA damage as determined by Comet assay in Lathyrus sativus L. root bioassay system. Antioxidants such as Tiron and dimethylthiourea significantly attenuated the ZnONP-induced oxidative and DNA damage, suggesting the involvement of ROS therein. Our study demonstrated that both ZnONP-GS and ZnONP-S induced oxidative stress and DNA damage to a similar extent but were significantly less potent than Zn2+ alone.

The effect and fate of water-soluble carbon nanodots in maize (Zea mays L.).

Science.gov (United States)

Chen, Jing; Dou, Runzhi; Yang, Zhongzhou; Wang, Xiaoping; Mao, Chuanbin; Gao, Xiang; Wang, Li

2016-08-01

In this study, the toxicity of water-soluble carbon nanodots (C-dots) to maize (Zea mays L.) and their uptake and transport in plants were investigated. After exposed in sand matrix amended with 0-2000 mg/L C-dots for 4 weeks, we found that the phytotoxicity of C-dots was concentration-dependent. C-dots at 250 and 500 mg/L showed no toxicity to maize. However, 1000 and 2000 mg/L C-dots significantly reduced the fresh weight of root by 57% and 68%, and decreased the shoot fresh weight by 38% and 72%, respectively. Moreover, in maize roots, the exposure of C-dots at 2000 mg/L significantly increased the H2O2 content and lipid peroxidation (6.5 and 1.65 times higher, respectively), as well as, the antioxidant enzymes activities, up to 2, 1.5, 1.9 and 1.9 times higher for catalase, ascorbate peroxidase, guaiacol peroxidase and superoxide dismutase, respectively. On the other hand, C-dots were observed in detached root-cap cells, cortex and vascular bundle of roots and mesophyll cells of leaves through fluorescence microscopy analysis, suggesting that C-dots were absorbed and translocated systemically in maize. Remarkably, a certain amount of C-dots were excreted out from leaf blade. To our knowledge, this is the first study combined phenotypic observation with physiologic responses and bioaccumulation and translocation analysis of C-dots to investigate their effect and fate in maize.

Physiological responses of Brassica napus to fulvic acid under water stress: Chlorophyll a fluorescence and antioxidant enzyme activity

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Ramin Lotfi

2015-10-01

Full Text Available The ameliorative effect of fulvic acid (0, 300, and 600 mg L− 1 on photosystem II and antioxidant enzyme activity of the rapeseed (Brassica napus L. plant under water stress (60, 100, and 140 mm evaporation from class A pan was studied using split plots in a randomized complete block design with three replications. Results indicated that application of fulvic acid (FA improved the maximum quantum efficiency of PSII (Fv/Fm and performance index (PI of plants under both well-watered and limited-water conditions. The time span from Fo to Fm and the energy necessary for the closure of all reaction centers was significantly increased, but the size of the plastoquinone pool was reduced with increasing water stress levels. Plants treated with FA had higher peroxidase and catalase activities under all irrigation conditions. Activities of ascorbate peroxidase and superoxide dismutase in plants increased with increasing water stress. Malondialdehyde increased under severe water stress, but application of FA significantly decreased lipid peroxidation. Production of reactive oxygen species (ROS is a common phenomenon in plants under stress. Under this condition, the balance between the production of ROS and the quenching activity of antioxidants is upset, often resulting in oxidative damage. In this study, application of FA significantly increased fluorescence of chlorophyll a, inhibiting ROS production and enhancing antioxidant enzymes activity that destroyed ROS. Thus, ROS in plant cells was reduced under water stress by application of FA and consequently lipid peroxidation was reduced.

[Effects of exogenous silicon on physiological characteristics of cucumber seedlings under ammonium stress].

Science.gov (United States)

Gao, Qing-Hai; Wang, Ya-Kun; Lu, Xiao-Min; Jia, Shuang-Shuang

2014-05-01

The present study evaluated the effects of exogenous silicon on growth and physiological characteristics of hydroponically cultured cucumber seedlings under ammonium stress. The results showed that the growth, especially the aerial part growth of cucumber seedlings cultured with ammonium were significantly inhibited than those with nitrate, especially after treatment for 10 d, the aerial part fresh mass of cucumber seedlings were reduced 6.17 g per plant. The accumulation of reactive oxygen species (ROS) was also promoted in cucumber seedlings under ammonium, and the contents of O2*- and H2O2 were significantly increased in cucumber leaves. With the exogenous silicon treatment, the activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), ascorbate peroxidase (APX) were significantly improved, the ability to remove reactive oxygen species was enhanced, the contents of O2*- and H2O2 were significantly reduced in cucumber leaves, decreasing the reactive oxygen damage to the cell membrane, and the ratio of electrolyte leakage and the content of MDA in cucumber leaves. Also, with exogenous silicon treatment, the plasma membrane and activity of vacuolar membrane H(+)-ATP was significantly increased, transport capacity of intracellular proton was improved, and the level of ammonium in cucumber body was significantly reduced, thereby reducing the toxicity of ammonium. In conclusion, exogenous silicon could relieve ammonium stress, by increasing the antioxidant enzyme activity, H(+)-ATP activity, and decreasing the ammonium content in cucumber seedlings.

Ozone, sulfur dioxide, and ultraviolet B have similar effects on mRNA accumulation of antioxidant genes in Nicotiana plumbaginifolia L.

Energy Technology Data Exchange (ETDEWEB)

Willekens, H.; Van Camp, W.; Van Montagu, M.; Inze, D. [Laboratoire Associe de l`Institut National de la Recherche Agronomique (France); Langebartels, C.; Sandermann, H. Jr. [Universiteit Gent (Belgium)]|[Institut fuer Biochemische Pflanzenpathologie, Oberschleissheim (Germany)

1994-11-01

We have studied the expression of antioxidant genes in response to near ambient conditions of O{sub 3}, SO{sub 2}, and ultraviolet B (UV-B) in Nicotiana plumbaginifolia L. The genes analyzed encode four different superoxide dismutases (SODs), three catalases (Cat1, Cat2, and Cat3), the cytosolic ascorbate peroxidase (cyt APx), and glutathione peroxidase (GPx). The experimental setup for each treatment was essentially the same and caused no visible damage, thus allowing direct comparison of the different stress responses. Our data showed that the effects of O{sub 3}, SO{sub 2}, and UV-B on the antioxidant genes are very similar, although the response to SO{sub 2} is generally less pronounced and delayed. The effects of the different stresses are characterized by a decline in Cat1, a moderate increase in Cat3, and a strong increase in Cat2 and GPx. Remarkably, SODs and cyt APx were not affected. Analysis of SOD and APx expression in the ozone-sensitive Nicotiana tabacum L. cv PBD6 revealed that induction of the cytosolic copper/zinc SOD and cyt APx occurs only with the onset of visible damage. It is proposed that alterations in mRNA levels of catalases and GPx, but not of SODs and cyt APx, form part of the initial antioxidant response to O{sub 3}, SO{sub 2}, and UV-B in Nicotiana. 57 refs., 4 figs.

Deficiency and toxicity of boron: Alterations in growth, oxidative damage and uptake by citrange orange plants.

Science.gov (United States)

Shah, Asad; Wu, Xiuwen; Ullah, Abid; Fahad, Shah; Muhammad, Riaz; Yan, Lei; Jiang, Cuncang

2017-11-01

Boron (B) deficiency and toxicity are the major factors that affect plant growth and yield. The present study revealed the effect of B deficiency and toxicity on plant growth, morphology, physiology, and cell structure. A hydroponic culture experiment was conducted with five B levels, B deficient (B0), sufficient (B20, B10, B40) and toxic (B100). Our results show that both B deficient as well as excess level inhibit plant growth. In B deficiency, the major visible symptoms were appeared in roots, while B excess burned the leaf margin of older leaves. The antioxidant enzymes including superoxide dismutase (SOD), peroxidase (POD), catalase (CAT) and ascorbate peroxidase (APX) decreased at B deficiency and also decreased up to some extent at B excess, while in sufficient treatments, the higher antioxidant enzymes were found at B20. In addition, the MDA concentration decreased at B deficiency and increased with B concentration. Moreover, the photosynthetic rate, transpiration rate, stomatal conductance, leaf gas exchange and intercellular CO 2 were reduced at both B deficiency as well as excess and higher at sufficient B20 treatment significantly. The chlorophyll and carotenoid content increased at B20 treatment, while decreased at B deficiency and excess. The middle lamellae of cell wall were found thick at B excess and normal at B20. The current study revealed that B deficiency as well as excess concentration affect plant growth and various morpho-physiological processes. Copyright © 2017 Elsevier Inc. All rights reserved.

Effect of salinity and silicon application on oxidative damage of sorghum [sorghum bicolor (L.) moench.

International Nuclear Information System (INIS)

Kafi, M.; Nabati, J.; Masoumi, A.; Mehrgerdi, M.Z.

2011-01-01

Application of silicon (Si) to soil is considered as an alternative approach to alleviate salinity stress in crop plants. Therefore, a field experiment was conducted to investigate the effects of Si application [control (without Si), 1.44 and 1.92 g.kg /sup -1/ soil on membrane stability index (MSI), relative water content (RWC), leaf proline, soluble sugars, antioxidant activity, total phenols and dry matter accumulation of two sorghum (Sorghum bicolor) cultivars under three levels of salinity of irrigation water (5.2, 10.5 and 23.1 dS m/sup -1/ . The results showed that leaf proline content, activities of ascorbate peroxidase (APX) and glutathione reductase (GR), Na/sup +/ concentration significantly increased only at high level of salinity, while, RWC Si caused an and dry matter accumulation were significantly decreased at all salinity levels. Soil application of 1.44 g.kg/sup -1/ increase in the activities of APX, catalase (CAT), superoxide dismutase (SOD), peroxidase (PRO), glutathione reductase soil Si caused an increase in membrane stabilityindex, (GR), total antioxidant and total phenol contents and 1.92 g.kg/sup -1/ soluble sugar and total phenol contents, CAT, SOD and total antioxidant activity. Soluble sugars, total phenols, SOD and total antioxidant activity and dry matter accumulation in cv. Omidbakhsh were higher than those in cv. Sepideh. In conclusion, alleviation of salinity stress by exogenous application of Si was found to be associated partly with enhanced antioxidant activity. (author)

Association of antioxidative enzymes with the synergistic effect of selenium and UV irradiation in enhancing plant growth

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T. XUE

2008-12-01

Full Text Available Selenium (Se is able to defend human and animal cells against UV(B stress. Higher plants are generally considered not to require Se but to have a low tolerance to it. However, recently it has been demonstrated that Se is able to protect also plants against UV-induced oxidative stress and even to promote the growth of plants subjected to high-energy light. In the present study the effects of Se on antioxidative enzymes possibly associated with this synergistic effect were investigated. Ryegrass and lettuce were grown in soil supplemented with Se at 0, 0.1 or 1.0 mg kg-1 under normal light or subjected to UV episodes. Lipid peroxidation and the changes of antioxidative enzymes were measured at two growing stages. The positive synergistic effect of the lower Se dosage and UV was found to be at least partly associated with the antioxidative role of Se through increased glutathione peroxidase (GSH-Px and catalase (CAT activity, whereas ascorbate peroxidase (APX responded negatively to both factors. The contribution of the other enzymes studied seemed to be plant-specific: glutathione S-transferase (GST increased in both ryegrass assays and superoxide dismutase (SOD in the first lettuce assay. At the higher addition level Se acted as a pro-oxidant and diminished fresh weight yields. UV irradiation alleviated the toxicity coincidently with increase of CAT in ryegrass and SOD in lettuce.;

[Alleviation of salt stress during maize seed germination by presoaking with exogenous sugar].

Science.gov (United States)

Zhao, Ying; Yang, Ke-jun; Li, Zuo-tong; Zhao, Chang-jiang; Xu, Jing-yu; Hu, Xue- wei; Shi, Xin-xin; Ma, Li-feng

2015-09-01

The maize variety Kenyu 6 was used to study the effects of exogenous glucose (Glc) and sucrose (Suc) on salt tolerance of maize seeds at germination stage under 150 mmol · L(-1) NaCl treatment. Results showed that under salt stress condition, 0.5 mmol · L(-1) exogenous Glc and Suc presoaking could promote seed germination and early seedling growth. Compared with the salt treatment, Glc presoaking increased the shoot length, radicle length and corresponding dry mass up to 1.5, 1.3, 2.1 and 1.8 times, and those of the Suc presoaking treatment increased up to 1.7, 1.3. 2.7 and 1.9 times, respectively. Exogenous Glc and Suc presoaking resulted in decreased levels of thiobarbituric acid reactive substances (TBARS) and hydrogen peroxide (H2O2) content of maize shoot under salt stress, which were lowered by 24.9% and 20.6% respectively. Exogenous Glc and Suc presoaking could increase the activities of superoxide dismutase (SOD), ascorbate peroxidase (APX), glutathione peroxidase (GPX), glutathione reductase (GR) and induce glucose-6-phosphate dehydrogenase (G6PDH) activity of maize shoot under salt stress. Compared with the salt treatment. Glc presoaking increased the activity of SOD, APX, GPX, GR and G6PDH by 66.2%, 62.9%, 32.0%, 38.5% and 50.5%, and those of the Suc presoaking increased by 67.5%, 59.8%, 30.0%, 38.5% and 50.4%, respectively. Glc and Suc presoaking also significantly increased the contents of ascorbic acid (ASA) and glutathione (GSH), ASA/DHA and GSH/GSSG. The G6PDH activity was found closely related with the strong antioxidation capacity induced by exogenous sugars. In addition, Glc and Suc presoaking enhanced K+/Na+ in maize shoot by 1.3 and 1.4 times of water soaking salt treatment, respectively. These results indicated that exogenous Glc and Suc presoaking could improve antioxidation capacity of maize seeds and maintain the in vivo K+/Na+ ion balance to alleviate the inhibitory effect of salt stress on maize seed germination.

Salt-tolerant rootstock increases yield of pepper under salinity through maintenance of photosynthetic performance and sinks strength.

Science.gov (United States)

Penella, Consuelo; Landi, Marco; Guidi, Lucia; Nebauer, Sergio G; Pellegrini, Elisa; San Bautista, Alberto; Remorini, Damiano; Nali, Cristina; López-Galarza, Salvador; Calatayud, Angeles

2016-04-01

The performance of a salt-tolerant pepper (Capsicum annuum L.) accession (A25) utilized as a rootstock was assessed in two experiments. In a first field experiment under natural salinity conditions, we observed a larger amount of marketable fruit (+75%) and lower Blossom-end Root incidence (-31%) in commercial pepper cultivar Adige (A) grafted onto A25 (A/A25) when compared with ungrafted plants. In order to understand this behavior a second greenhouse experiment was conducted to determine growth, mineral partitioning, gas exchange and chlorophyll a fluorescence parameters, antioxidant systems and proline content in A and A/A25 plants under salinity conditions (80 mM NaCl for 14 days). Salt stress induced significantly stunted growth of A plants (-40.6% of leaf dry weight) compared to the control conditions, while no alterations were observed in A/A25 at the end of the experiment. Accumulation of Na(+) and Cl(-) in leaves and roots was similar in either grafted or ungrafted plants. Despite the activation of protective mechanisms (increment of superoxide dismutase, catalase, ascorbate peroxidase activity and non-photochemical quenching), A plants showed severely reduced photosynthetic CO2 assimilation (-45.6% of AN390) and substantial buildup of malondialdehyde (MDA) by-product, suggesting the inability to counteract salt-triggered damage. In contrast, A/A25 plants, which had a constitutive enhanced root apparatus, were able to maintain the shoot and root growth under salinity conditions by supporting the maintained photosynthetic performance. No increases in catalase and ascorbate peroxidase activities were observed in response to salinity, and MDA levels increased only slightly; indicating that alleviation of oxidative stress did not occur in A/A25 plants. In these plants the increased proline levels could protect enzymatic stability from salt-triggered damage, preserving the photosynthetic performance. The results could indicate that salt stress was vanished by

Exogenous Melatonin Application Delays Senescence of Kiwifruit Leaves by Regulating the Antioxidant Capacity and Biosynthesis of Flavonoids

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Dong Liang

2018-04-01

Full Text Available Melatonin, a multiple signal molecule, plays important roles in delaying senescence during the development of plants. Because few species have been studied for the effect of exogenous melatonin on anti-aging, the plausible mechanism of melatonin of anti-aging effects on other plant species has remained largely unknown. In the present study, the effects of exogenous melatonin on leaf senescence in kiwifruit were examined during natural aging after melatonin (200 μM or water (Control pretreatment. The decreased membrane damage and lower hydrogen peroxide (H2O2 content due to the enhanced scavenging activity of antioxidant enzymes peroxidase (POD, superoxide dismutase (SOD, and catalase (CAT demonstrated that melatonin effectively delayed the aging of kiwifruit leaves. Likewise, owing to up-regulated expression of chlorophyll a/b-binding protein (CAB gene in the sampled leaves pretreated with melatonin, chlorophyll degradation decreased. Therefore, osmoregulatory substances in sampled leaves accumulated (e.g., soluble sugar and soluble protein and seedling cell environment stability was maintained. Simultaneously, melatonin decreased H2O2 concentration owing to increased glutathione (GSH and ascorbate (AsA content, and the expression levels of glutathione reductase (GR, ascorbate peroxidase (APX, monodehydroascorbate reductase (MDAR, dehydroascorbate reductase (DHAR were up-regulated by melatonin application, indicating that the increase of GSH and AsA was attributed to the expression of these genes. In addition, a large amount of flavonoids accumulated in seedlings pretreated with melatonin, and transcript levels of eight genes involved in flavonoid synthesis, including phenylalanine ammonia-lyase (PAL, cinnamate-4-hydroxymate (C4H, chalcone synthase (CHS, flavanone 3-hydroxylase (F3H, flavonol synthase (FNS, leucoanthocyanin reductase (LAR, anthocyanin reductase (ANR, flavonoid 3-O-glucosyltransferase (UFGT were enhanced in response to melatonin

Toxic effects of imidazolium ionic liquids on the green seaweed Ulva lactuca: oxidative stress and DNA damage.

Science.gov (United States)

Kumar, Manoj; Trivedi, Nitin; Reddy, C R K; Jha, Bhavanath

2011-11-21

The green credentials of ionic liquids (ILs) are being increasingly questioned due to the growing evidence of their toxicity to aquatic ecosystems, although the mechanisms of toxicity are unknown. This study provides insights into the mechanism of toxicity and biological effects of 1-alkyl-3-methylimidazolium bromide [C(n)mim]Br (n = 4 to 16) on the marine macroalga Ulva lactuca. The cell viability of this alga during IL exposure was found to be negatively correlated to the chain length of the alkyl group. The IL ([C(12)mim]Br) exposure triggers the generation of reactive oxygen species (ROS viz. O(2)(•-), H(2)O(2), and OH(•)), damage of the membrane and DNA, and inhibition of antioxidant systems in the alga. The enhanced production of ROS and lipid peroxidation in the alga subjected to LC(50) concentration for 4 days was largely attributed to lipoxygenase (LOX) activity coupled with the induction of two LOX isoforms (~80 kDa and ~55 kDa). Pretreatment of the algal thallus with enzyme inhibitors such as diphenylene iodonium, sodium azide, cantharidin, and oxadiazoloquinoxalin-1-one, prior to [C(12)mim]Br exposure showed the regulation of ROS by the activation of membrane bound NADPH-oxidase and cytochrome oxidase. The IL exposure resulted in the accumulation of n-3 and n-6 fatty acids at 0.5 LC(50) concentration indicating the induction of desaturase enzymes. Furthermore, antioxidant enzyme activities such as superoxide dismutase (SOD), ascorbate peroxidase (APX), and glutathione reductase (GR) were enhanced by 1.3-2.0-fold, while glutathione peroxidase (GSH-Px) diminished, together with a higher regeneration rate of reduced ascorbate and glutathione. The isoforms of antioxidant enzymes, namely, Mn-SOD (~85 kDa), APX (~125 and 45 kDa), and GR (~135 kDa) regulated differentially to IL exposure. The comet assay performed for the first time for seaweeds revealed the significant induction of DNA damage (>50-70% increase in % tail DNA over control) in alga exposed

Effect of Storage Temperature on Vitamin C, Total Phenolics, UPLC Phenolic Acid Profile and Antioxidant Capacity of Eleven Potato (Solanum tuberosum Varieties

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Joseph Hubert Yamdeu Galani