Uranium and cadmium provoke different oxidative stress responses in Lemna minor L.

PubMed

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.

Crystal structures of dye-decolorizing peroxidase with ascorbic acid and 2,6-dimethoxyphenol.

PubMed

Yoshida, Toru; Tsuge, Hideaki; Hisabori, Toru; Sugano, Yasushi

2012-12-14

The structure of dye-decolorizing peroxidase (DyP)-type peroxidase differs from that of other peroxidase families, indicating that DyP-type peroxidases have a different reaction mechanism. We have determined the crystal structures of DyP with ascorbic acid and 2,6-dimethoxyphenol at 1.5 and 1.4Å, respectively. The common binding site for both substrates was located at the entrance of the second cavity leading from the DyP molecular surface to heme. This resulted in a hydrogen bond network connection between each substrate and the heme distal side. This network consisted of water molecules occupying the second cavity, heme 6-propionate, Arg329, and Asn313. This network is consistent with the proton transfer pathway from substrate to DyP. Copyright © 2012 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

Ascorbate synthesis pathway, dual role of ascorbate in bone homeostasis

USDA-ARS?s Scientific Manuscript database

Using mouse gene knock-out models, we identify aldehyde reductase (EC 1.1.1.2, Akr1a4 (GR)) and aldose reductase (EC 1.1.1.21, Akr1b3 (AR)) as the enzymes responsible for conversion of D-glucuronate to L-gulonate, a key step in the ascorbate (ASC) synthesis pathway in mice. The gene knock-out (KO) m...

Mechanism of ascorbic acid interference in biochemical tests that use peroxide and peroxidase to generate chromophore.

PubMed

Martinello, Flávia; Luiz da Silva, Edson

2006-11-01

Ascorbic acid interferes negatively in peroxidase-based tests (Trinder method). However, the precise mechanism remains unclear for tests that use peroxide, a phenolic compound and 4-aminophenazone (4-AP). We determined the chemical mechanism of this interference, by examining the effects of ascorbic acid in the reaction kinetics of the production and reduction of the oxidized chromophore in urate, cholesterol, triglyceride and glucose tests. Reaction of ascorbic acid with the Trinder method constituents was also verified. Ascorbic acid interfered stoichiometrically with all tests studied. However, it had two distinct effects on the reaction rate. In the urate test, ascorbic acid decreased the chromophore formation with no change in its production kinetics. In contrast, in cholesterol, triglyceride and glucose tests, an increase in the lag phase of color development occurred. Of all the Trinder constituents, only peroxide reverted the interference. In addition, ascorbic acid did not interfere with oxidase activity nor reduce significantly the chromophore formed. Peroxide depletion was the predominant chemical mechanism of ascorbic acid interference in the Trinder method with phenolics and 4-AP. Distinctive effects of ascorbic acid on the reaction kinetics of urate, cholesterol, glucose and triglyceride might be due to the rate of peroxide production by oxidases.

Exogenous hydrogen peroxide reversibly inhibits root gravitropism and induces horizontal curvature of primary root during grass pea germination.

PubMed

Jiang, Jinglong; Su, Miao; Wang, Liyan; Jiao, Chengjin; Sun, Zhengxi; Cheng, Wei; Li, Fengmin; Wang, Chongying

2012-04-01

During germination in distilled water (dH(2)O) on a horizontally positioned Petri dish, emerging primary roots of grass pea (Lathyrus sativus L.) grew perpendicular to the bottom of the Petri dish, due to gravitropism. However, when germinated in exogenous hydrogen peroxide (H(2)O(2)), the primary roots grew parallel to the bottom of the Petri dish and asymmetrically, forming a horizontal curvature. Time-course experiments showed that the effect was strongest when H(2)O(2) was applied prior to the emergence of the primary root. H(2)O(2) failed to induce root curvature when applied post-germination. Dosage studies revealed that the frequency of primary root curvature was significantly enhanced with increased H(2)O(2) concentrations. This curvature could be directly counteracted by dimethylthiourea (DMTU), a scavenger of H(2)O(2), but not by diphenylene iodonium (DPI) and pyridine, inhibitors of H(2)O(2) production. Exogenous H(2)O(2) treatment caused both an increase in the activities of H(2)O(2)-scavenging enzymes [including ascorbate peroxidase (APX: EC 1.11.1.11), catalase (CAT: EC 1.11.1.6) and peroxidase (POD: EC 1.11.1.7)] and a reduction in endogenous H(2)O(2) levels and root vitality. Although grass pea seeds absorbed exogenous H(2)O(2) during seed germination, DAB staining of paraffin sections revealed that exogenous H(2)O(2) only entered the root epidermis and not inner tissues. These data indicated that exogenously applied H(2)O(2) could lead to a reversible loss of the root gravitropic response and a horizontal curvature in primary roots during radicle emergence of the seedling. Copyright © 2012 Elsevier Masson SAS. All rights reserved.

Implications of terminal oxidase function in regulation of salicylic acid on soybean seedling photosynthetic performance under water stress.

PubMed

Tang, Yanping; Sun, Xin; Wen, Tao; Liu, Mingjie; Yang, Mingyan; Chen, Xuefei

2017-03-01

The aim of this study is to investigate whether exogenous application of salicylic acid (SA) could modulate the photosynthetic capacity of soybean seedlings in water stress tolerance, and to clarify the potential functions of terminal oxidase (plastid terminal oxidase (PTOX) and alternative oxidase (AOX)) in SA' s regulation on photosynthesis. The effects of SA and water stress on gas exchange, pigment contents, chlorophyll fluorescence, enzymes (guaiacol peroxidase (POD; EC 1.11.1.7), superoxide dismutase (SOD; EC 1.15.1.1), catalase (CAT; EC 1.11.1.6), ascorbate peroxidase (APX; EC 1.11.1.11) and NADP-malate dehydrogenase (NADP-MDH; EC1.1.1.82)) activity and transcript levels of PTOX, AOX1, AOX2a, AOX2b were examined in a hydroponic cultivation system. Results indicate that water stress significantly decreased the photosynthetic rate (Pn), stomatal conductance (Gs), transpiration rate (E), pigment contents (Chla + b, Chla/b, Car), maximum quantum yield of PSⅡphotochemistry (Fv/Fm), efficiency of excitation capture of open PSⅡcenter (Fv'/Fm'), quantum efficiency of PSⅡphotochemistry (ΦPSⅡ), photochemical quenching (qP), and increased malondialdehyde (MDA) content and the activity of all the enzymes. SA pretreatment led to significant decreases in Ci and MDA content, and increases in Pn, Gs, E, pigment contents, Fv/Fm, Fv'/Fm', ΦPSⅡ, qP, and the activity of all the enzymes. SA treatment and water stress alone significantly up-regulated the expression of PTOX, AOX1 and AOX2b. SA pretreatment further increased the transcript levels of PTOX and AOX2b of soybean seedling under water stress. These results indicate that SA application alleviates the water stress-induced decrease in photosynthesis may mainly through maintaining a lower reactive oxygen species (ROS) level, a greater PSⅡefficiency, and an enhanced alternative respiration and chlororespiration. PTOX and AOX may play important roles in SA-mediated resistance to water stress. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Response of antioxidant enzymes in Nicotiana tabacum clones during phytoextraction of heavy metals.

PubMed

Lyubenova, Lyudmila; Nehnevajova, Erika; Herzig, Rolf; Schröder, Peter

2009-07-01

Tobacco, Nicotiana tabacum, is a widely used model plant for growth on heavy-metal-contaminated sites. Its high biomass and deep rooting system make it interesting for phytoextraction. In the present study, we investigated the antioxidative activities and glutathione-dependent enzymes of different tobacco clones optimized for better Cd and Zn accumulation in order to characterize their performance in the field. The improved heavy metal resistance also makes the investigated tobacco clones interesting for understanding the plant defense enzyme system in general. Freshly harvested plant material (N. tabacum leaves) was used to investigate the antioxidative cascade in plants grown on heavy metal contaminated sites with and without amendments of different ammonium nitrate and ammonium sulfate fertilizers. Plants were grown on heavily polluted soils in north-east Switzerland. Leaves were harvested at the field site and directly deep frozen in liquid N(2). Studies were concentrated on the antioxidative enzymes of the Halliwell-Asada cycle, and spectrophotometric measurements of catalase (CAT, EC 1.11.1.6), ascorbate peroxidase (APX, EC 1.11.1.11), superoxide dismutase (SOD, EC 1.15.1.1), glutathione peroxidase (GPX, EC 1.11.1.9), glutathione reductase (GR, EC 1.6.4.2), glutathione S-transferase (GST, EC 2.5.1.18) were performed. We tried to explain the relationship between fertilizer amendments and the activity of the enzymatic defense systems. When tobacco (N. tabacum) plants originating from different mutants were grown under field conditions with varying fertilizer application, the uptake of cadmium and zinc from soil increased with increasing biomass. Depending on Cd and Zn uptake, several antioxidant enzymes showed significantly different activities. Whereas SOD and CAT were usually elevated, several other enzymes, and isoforms of GST were strongly inhibited. Heavy metal uptake represents severe stress to plants, and specific antioxidative enzymes are induced at the cost of more general reactions of the Halliwell-Asada cycle. In well-supplied plants, the glutathione level remains more or less unchanged. The lack of certain glutathione S-transferases upon exposure to heavy metals might be problematic in cases when organic pollutants coincide with heavy metal pollution. When planning phytoremediation of sites, mixed pollution scenarios have to be foreseen and plants should be selected according to both, their stress resistance and hyperaccumulative capacity.

Ectopic Expression of a Horseradish Peroxidase Enhances Growth Rate and Increases Oxidative Stress Resistance in Hybrid Aspen

PubMed Central

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

2003-01-01

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 × 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. PMID:12857800

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

PubMed

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.

The role of ascorbate peroxidase, guaiacol peroxidase, and polysaccharides in cassava (Manihot esculenta Crantz) roots under postharvest physiological deterioration.

PubMed

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

2016-04-15

This study aimed to investigate the role of ascorbate peroxidase (APX), guaiacol peroxidase (GPX), polysaccharides, and protein contents associated with the early events of postharvest physiological deterioration (PPD) in cassava roots. Increases in APX and GPX activity, as well as total protein contents occurred from 3 to 5 days of storage and were correlated with the delay of PPD. Cassava samples stained with Periodic Acid-Schiff (PAS) highlighted the presence of starch and cellulose. Degradation of starch granules during PPD was also detected. Slight metachromatic reaction with toluidine blue is indicative of increasing of acidic polysaccharides and may play an important role in PPD delay. Principal component analysis (PCA) classified samples according to their levels of enzymatic activity based on the decision tree model which showed GPX and total protein amounts to be correlated with PPD. The Oriental (ORI) cultivar was more susceptible to PPD. Copyright © 2015 Elsevier Ltd. All rights reserved.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tatsumi, Y.; Chachin, K.; Ogata, K.

The purpose of the experiment was to determine the changes of o- diphenol, ascorbic acid, and activities of polyphenol oxidase and peroxidase, accompanied with the browning by the low dose of gamma ray, in three parts of tuber tissue (cortex, vascular bundle, and pith), and to observe the relation between the browning and the changes of ihose compounds and enzyme activities. The odiphenol content increased in irradiated tabers and the increasing rate was greater in cortex and vascular bundle than in pith. The ascorbic acid content decreased with higher doses, and the decreasing rate was greater in cortex and vascularmore » bundle than in pith. The activities of polyphenol oxidase and peroxidase also increased in irradiated tubers. The activity of polyphenol oxidase increased more in cortex than in vascular bundle and pith and the activity of peroxidase increased more in vascular bundle than in cortex and pith. ln the potato tubers in which irradiation was conducted immediately after harvest, the browning was induced within several days after irradiation. However, in the potato tubers in which irradiation was conducted about 3 months, the browning did not occur after irradiation. The former showed the increase of o-diphenol content and the activities of these enzymes, and the decrease of ascorbic acid content, the latter did not show the changes of o-diphenol and ascorbic acid and activities of the enzymes. (auth)« less

[Light-dependent changes in the enzyme activity of the ascorbate-glutathione cycle and ascorbate oxidase in the leaves of pea].

PubMed

Mittova, V O; Igamberdiev, A U

2000-01-01

Light-determined activation of ferments of ascorbate-glutation cycle, ascorbate-oxidase in chloroplasts and cytosol is demonstrated as well as ascorbate-peroxidase, monodehydroascorbate-reductase, glutation-reductase and ascorbate-oxydase in mitochondria. On the other hands activity of mitochondrial dehydroascorbate-reductase increased on reduction of light most likely due to function of electron transport from glutation to dehydroascorbate in mitochondria. Glutation metabolism is proved to be endogenic catalytic process where the amount reconstructed glutation changes slowly with a delay and gradually follow light changes. Light dependable changes of glutation content in chloroplasts ensure resistance of ferment system again hydrogen peroxide and superoxide radicals that generate intensively at light.

A different role for hydrogen peroxide and the antioxidative system under short and long salt stress in Brassica oleracea roots

PubMed Central

Hernandez, Mercedes; Fernandez-Garcia, Nieves; Diaz-Vivancos, Pedro; Olmos, Enrique

2010-01-01

Salinity affects normal growth and development of plants depending on their capacity to overcome the induced stress. The present study was focused on the response and regulation of the antioxidant defence system in Brassica oleracea roots under short and long salt treatments. The function and the implications of hydrogen peroxide as a stressor or as a signalling molecule were also studied. Two different zones were analysed—the elongation and differentiation zone and the fully differentiated root zone—in order to broaden the knowledge of the different effects of salt stress in root. In general, an accumulation of hydrogen peroxide was observed in both zones at the highest (80 mM NaCl) concentration. A higher accumulation of hydrogen peroxide was observed in the stele of salt-treated roots. At the subcellular level, mitochondria accumulated hydrogen peroxide in salt-treated roots. The results confirm a drastic decrease in the antioxidant enzymes catalase, ascorbate peroxidase, and peroxidases under short salt treatments. However, catalase and peroxidase activities were recovered under long salt stress treatments. The two antioxidant molecules analysed, ascorbate and glutathione, showed a different trend during salt treatments. Ascorbate was progressively accumulated and its redox state maintained, but glutathione was highly accumulated at 24 h of salt treatment, but then its concentration and redox state progressively decreased. Concomitantly, the antioxidant enzymes involved in ascorbate and glutathione regeneration were modified under salt stress treatments. In conclusion, the increase in ascorbate levels and the maintenance of the redox state seem to be critical for root growth and development under salt stress. PMID:19906795

Kinetic study of the inactivation of ascorbate peroxidase by hydrogen peroxide.

PubMed Central

Hiner, A N; Rodríguez-López, J N; Arnao, M B; Lloyd Raven, E; García-Cánovas, F; Acosta, M

2000-01-01

The activity of ascorbate peroxidase (APX) has been studied with H(2)O(2) and various reducing substrates. The activity decreased in the order pyrogallol>ascorbate>guaiacol>2, 2'-azino-bis-(3-ethylbenzthiazoline-6-sulphonic acid) (ABTS). The inactivation of APX with H(2)O(2) as the sole substrate was studied. The number of H(2)O(2) molecules required for maximal inactivation of the enzyme was determined as approx. 2.5. Enzymic activity of approx. 20% of the original remained at the end of the inactivation process (i.e. approx. 20% resistance) when ascorbate or ABTS was used as the substrate in activity assays. With pyrogallol or guaiacol no resistance was seen. Inactivation by H(2)O(2) followed over time with ascorbate or pyrogallol assays exhibited single-exponential decreases in enzymic activity. Hyperbolic saturation kinetics were observed in both assay systems; a similar dissociation constant (0.8 microM) for H(2)O(2) was obtained in each case. However, the maximum rate constant (lambda(max)) obtained from the plots differed depending on the assay substrate. The presence of reducing substrate in addition to H(2)O(2) partly or completely protected the enzyme from inactivation, depending on how many molar equivalents of reducing substrate were added. An oxygen electrode system has been used to confirm that APX does not exhibit a catalase-like oxygen-releasing reaction. A kinetic model was developed to interpret the experimental results; both the results and the model are compared and contrasted with previously obtained results for horseradish peroxidase C. The kinetic model has led us to the conclusion that the inactivation of APX by H(2)O(2) represents an unusual situation in which no enzyme turnover occurs but there is a partition of the enzyme between two forms, one inactive and the other with activity towards reducing substrates such as ascorbate and ABTS only. The partition ratio is less than 1. PMID:10816425

Change in desiccation tolerance of maize embryos during development and germination at different water potential PEG-6000 in relation to oxidative process.

PubMed

Huang, Hui; Song, Songquan

2013-07-01

Desiccation tolerance is one of the most important traits determining seed survival during storage and under stress conditions. However, the mechanism of seed desiccation tolerance is still unclear in detail. In the present study, we used a combined model system, desiccation-tolerant and -sensitive maize embryos with identical genetic background, to investigate the changes in desiccation tolerance, malonyldialdehyde (MDA) level, hydrogen peroxide (H₂O₂) content and antioxidant enzyme activity during seed development and germination in 0, -0.6 and -1.2 MPa polyethylene glycol (PEG)-6000 solutions. Our results indicated that maize embryos gradually acquired and lost desiccation tolerance during development and germination, respectively. The acquirement and loss of desiccation tolerance of embryos during development and germination were related to the ability of antioxidant enzymes including superoxide dismutase (SOD, EC 1.15.1.1), ascorbate peroxidase (APX, EC 1.11.1.11), catalase (CAT, EC 1.11.1.6), glutathione reductase (GR, EC 1.6.4.2) and dehydroascorbate reductase (DHAR, EC 1.8.5.1) to scavenge reactive oxygen species (ROS) and to control MDA content. Compared with treatment in water, PEG-6000 treatment could markedly delay the loss of desiccation tolerance of germinating embryos by delaying water uptake and time course of germination, increasing GR activity and decreasing MDA content. Our data showed the combination of antioxidant enzyme activity and MDA content is a good parameter for assessing the desiccation tolerance of maize embryos. In addition, H₂O₂ accumulated in mature embryos and PEG-treated embryos after drying, which was at least partially related to a longer embryo/seedling length in rehydration and the physiological mechanisms of priming. Copyright © 2013. Published by Elsevier Masson SAS.

Peroxidase-like activity of the Co3O4 nanoparticles used for biodetection and evaluation of antioxidant behavior

NASA Astrophysics Data System (ADS)

Jia, Huimin; Yang, Dongfang; Han, Xiangna; Cai, Junhui; Liu, Haiying; He, Weiwei

2016-03-01

Nanostructured enzyme mimics are of great interest as promising alternatives to artificial enzymes for biomedical and catalytic applications. Studying the chemical interactions between antioxidants and nano-enzymes may result in a better understanding of the antioxidant capability of antioxidants and may help improve the function of artificial enzymes to better mimic natural enzymes. In this study, using Co3O4 nanoparticles (NPs) as peroxidase mimics to catalyze the oxidation of chromophoric substrates by H2O2, we developed a platform that acts as a biosensor for hydrogen peroxide and glucose and that can study the inhibitory effects of natural antioxidants on peroxidase mimics. This method can be applied specifically to glucose detection in real samples. Three natural antioxidants, gallic acid (GA), tannic acid (TA), and ascorbic acid (AA), were compared for their antioxidant capabilities. We found that these three antioxidants efficiently inhibit peroxidase-like activity with concentration dependence. The antioxidants showed different efficiencies, in the following order: tannic acid > gallic acid > ascorbic acid. They also showed distinct modes of inhibition based on different interaction mechanisms. This study serves as a proof-of-concept that nano-enzyme mimics can be used to evaluate antioxidant capabilities and to screen enzyme inhibitors.Nanostructured enzyme mimics are of great interest as promising alternatives to artificial enzymes for biomedical and catalytic applications. Studying the chemical interactions between antioxidants and nano-enzymes may result in a better understanding of the antioxidant capability of antioxidants and may help improve the function of artificial enzymes to better mimic natural enzymes. In this study, using Co3O4 nanoparticles (NPs) as peroxidase mimics to catalyze the oxidation of chromophoric substrates by H2O2, we developed a platform that acts as a biosensor for hydrogen peroxide and glucose and that can study the inhibitory effects of natural antioxidants on peroxidase mimics. This method can be applied specifically to glucose detection in real samples. Three natural antioxidants, gallic acid (GA), tannic acid (TA), and ascorbic acid (AA), were compared for their antioxidant capabilities. We found that these three antioxidants efficiently inhibit peroxidase-like activity with concentration dependence. The antioxidants showed different efficiencies, in the following order: tannic acid > gallic acid > ascorbic acid. They also showed distinct modes of inhibition based on different interaction mechanisms. This study serves as a proof-of-concept that nano-enzyme mimics can be used to evaluate antioxidant capabilities and to screen enzyme inhibitors. Electronic supplementary information (ESI) available: Fig. S1-S6. See DOI: 10.1039/c6nr00860g

Abiotic Stress Tolerance in Plants: Myriad Roles of Ascorbate Peroxidase

PubMed Central

Pandey, Saurabh; Fartyal, Dhirendra; Agarwal, Aakrati; Shukla, Tushita; James, Donald; Kaul, Tanushri; Negi, Yogesh K.; Arora, Sandeep; Reddy, Malireddy K.

2017-01-01

One of the most significant manifestations of environmental stress in plants is the increased production of Reactive Oxygen Species (ROS). These ROS, if allowed to accumulate unchecked, can lead to cellular toxicity. A battery of antioxidant molecules is present in plants for keeping ROS levels under check and to maintain the cellular homeostasis under stress. Ascorbate peroxidase (APX) is a key antioxidant enzyme of such scavenging systems. It catalyses the conversion of H2O2 into H2O, employing ascorbate as an electron donor. The expression of APX is differentially regulated in response to environmental stresses and during normal plant growth and development as well. Different isoforms of APX show differential response to environmental stresses, depending upon their sub-cellular localization, and the presence of specific regulatory elements in the upstream regions of the respective genes. The present review delineates role of APX isoforms with respect to different types of abiotic stresses and its importance as a key antioxidant enzyme in maintaining cellular homeostasis. PMID:28473838

Exogenous abscisic acid increases antioxidant enzymes and related gene expression in pepper (Capsicum annuum) leaves subjected to chilling stress.

PubMed

Guo, W L; Chen, R G; Gong, Z H; Yin, Y X; Ahmed, S S; He, Y M

2012-11-28

To elucidate how physiological and biochemical mechanisms of chilling stress are regulated by abscisic acid (ABA) pretreatment, pepper variety (cv. 'P70') seedlings were pretreated with 0.57 mM ABA for 72 h and then subjected to chilling stress at 10°/6°C (day/night). Chilling stress caused severe necrotic lesions on the leaves and increased malondialdehyde and H(2)O(2) levels. Activities of monodehydroascorbate reductase (DHAR), dehydroascorbate reductase, glutathione reductase, guaiacol peroxidase, ascorbate peroxidase, ascorbate, and glutathione increased due to chilling stress during the 72 h, while superoxide dismutase and catalase activities decreased during 24 h, suggesting that chilling stress activates the AsA-GSH cycle under catalase deactivation in pepper leaves. ABA pretreatment induced significant increases in the above-mentioned enzyme activities and progressive decreases in ascorbate and glutathione levels. On the other hand, ABA-pretreated seedlings under chilling stress increased superoxide dismutase and guaiacol peroxidase activities and lowered concentrations of other antioxidants compared with untreated chilling-stressed plants. These seedlings showed concomitant decreases in foliage damage symptoms, and levels of malondialdehyde and H(2)O(2). Induction of Mn-SOD and POD was observed in chilling-stressed plants treated with ABA. The expression of DHAR1 and DHAR2 was altered by chilling stress, but it was higher in the presence than in the absence of ABA at 24 h. Overall, the results indicate that exogenous application of ABA increases tolerance of plants to chilling-induced oxidative damage, mainly by enhancing superoxide dismutase and guaiacol peroxidase activities and related gene expression.

The response of antioxidant systems in Nostoc sphaeroides against UV-B radiation and the protective effects of exogenous antioxidants

NASA Astrophysics Data System (ADS)

Wang, Gaohong; Hu, Chunxiang; Li, Dunhai; Zhang, Delu; Li, Xiaoyan; Chen, Kun; Liu, Yongding

UV radiation is one of many harmful factors found in space that are detrimental to organisms on earth in space exploration. In the present work, we examined the role of antioxidant system in Nostoc sphaeroides Kütz (Cyanobacterium) and the effects of exogenously applied antioxidant molecules on its photosynthetic rate under UV-B radiation. It was found that UV-B radiation promoted the activity of antioxidant system to protect photosystem II (PSII) and exogenously applied antioxidant: sodium nitroprusside (SNP) and N-acetylcysteine (NAC) had an obvious protection on PSII activity under UV-B radiation. The activity of superoxide dismutase (SOD, EC 1.15.1.1), catalase (CAT, EC 1.11.1.6), peroxidase (POD, EC 1.11.1.7) and content of MDA (malondialdehyde) and ASC (ascorbate) were improved by 0.5 mM and 1 mM SNP, but 0.1 mM SNP decreased the activity of antioxidant system. Addition of exogenous NAC decreased the activity of SOD, POD, CAT and the content MDA and ASC. In contrast, exogenously applied NAC increased GSH content. The results suggest that exogenous SNP and NAC may protect algae by different mechanisms: SNP may play double roles as both sources of reactive free radicals as well as ROS scavengers in mediating the protective role of PSII on algae under UV-B radiation. On the other hand, NAC functions as an antioxidant or precursor of glutathione, which could protect PSII directly from UV-B radiation.

Involvement of the leaf antioxidant system in the response to soil flooding in two Trifolium genotypes differing in their tolerance to waterlogging.

PubMed

Simova-Stoilova, L; Demirevska, K; Kingston-Smith, A; Feller, U

2012-02-01

A comparative study of the response to waterlogging in a tolerant (Trifolium repens L., white clover cultivar Rivendel) and susceptible (Trifolium pratense L., red clover cultivar Raya) plants was undertaken to reveal the possible link between plant performance and oxidative stress protection mechanisms in leaves. Two weeks of soil waterlogging induced visible leaf damage in the susceptible genotype. In the tolerant one, signs of stress suffering appeared a week later. Waterlogging induced hydrogen peroxide accumulation in both clover species. The content of lipid hydroperoxides markedly increased in the sensitive plants along with stress prolongation, while in the tolerant ones their initial rise was followed by return to control levels. In the leaves of both genotypes ascorbic acid content increased following treatment, accompanied by transient increase in oxidized ascorbate. Superoxide dismutase (SOD) isoforms responded differently to the treatment, CuZn SOD isoforms being inhibited; catalase activity diminished while peroxidase activity increased and a new peroxidase isoform was detected after prolonged waterlogging in both clover species. Results support more pronounced oxidative secondary stress in red clover leaves as a result of waterlogging with progressively increased oxidative membrane injury, protein loss, and peroxidase activity enhancement. White clover presented relative protein stability and earlier and more active ascorbate involvement in the antioxidative protection. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

Effective salt criteria in callus-cultured tomato genotypes.

PubMed

Dogan, Mahmut; Tipirdamaz, Rukiye; Demir, Yavuz

2010-01-01

Na+, Cl-, K+, Ca2+, and proline contents, the rate of lipid peroxidation level in terms of malondialdehyde (MDA) and chlorophyll content, and the changes in the activity of antioxidant enzymes, such as superoxide dismutase (SOD: EC 1.15.1.1), catalase (CAT: EC 1.11.1.6), ascorbate peroxidase (APX: EC 1.11.1.11), and glutathione reductase (GR: EC 1.6.4.2), in tissues of five tomato cultivars in salt tolerance were investigated in a callus culture. The selection of effective parameters used in these tomato genotypes and to find out the use of in vitro tests in place of in vivo salt tolerance tests were investigated. As a material, five different tomato genotypes during a 10-day time period were used, and 150 mM NaCl was applied at callus plant tissue. The exposure to NaCl induced a significant increase in MDA content in both salt-resistant and salt-sensitive cultivars. But the MDA content was higher in salt-sensitive cultivars. The chlorophyll content was more decreased in salt-sensitive than in salt-resistant ones. The proline amount was more increased in salt-sensitive than in salt-resistant ones. It has been reported that salt-tolerant plants, besides being able to regulate the ion and water movements, also exhibit a strong antioxidative enzyme system for effective removal of ROS. The degree of damage depends on the balance between the formation of ROS and its removal by the antioxidative scavenging system that protects against them. Exclusion or inclusion of Na+, Cl-, K+, and Ca2+, antioxidant enzymes and MDA concentration play a key protective role against stress, and this feature at the callus plant tissue used as an identifier for tolerance to salt proved to be an effective criterion.

Arsenate exposure affects amino acids, mineral nutrient status and antioxidants in rice (Oryza sativa L.) genotypes.

PubMed

Dwivedi, S; Tripathi, R D; Tripathi, P; Kumar, A; Dave, R; Mishra, S; Singh, R; Sharma, D; Rai, U N; Chakrabarty, D; Trivedi, P K; Adhikari, B; Bag, M K; Dhankher, O P; Tuli, R

2010-12-15

Simulated pot experiments were conducted on four rice (Oryza sativa L.) genotypes (Triguna, IR-36, PNR-519, and IET-4786) to examine the effects of As(V) on amino acids and mineral nutrient status in grain along with antioxidant response to arsenic exposure. Rice genotypes responded differentially to As(V) exposure in terms of amino acids and antioxidant profiles. Total amino acid content in grains of all rice genotypes was positively correlated with arsenic accumulation. While, most of the essential amino acids increased in all cultivars except IR-36, glutamic acid and glycine increased in IET-4786 and PNR-519. The level of nonprotein thiols (NPTs) and the activities of superoxide dismutase (SOD; EC 1.15.1.1), glutathione reductase (GR; EC 1.6.4.2) and ascorbate peroxidase (APX; EC 1.11.1.11) increased in all rice cultivars except IET-4786. A significant genotypic variation was also observed in specific arsenic uptake (SAU; mg kg(-1)dw), which was in the order of Triguna (134) > IR-36 (71) > PNR-519 (53) > IET-4786 (29). Further, application of As(V) at lower doses (4 and 8 mg L(-1) As) enhanced the accumulation of selenium (Se) and other nutrients (Fe, P, Zn, and S), however, higher dose (12 mg L(-1) As) limits the nutrient uptake in rice. In conclusion, low As accumulating genotype, IET-4786, which also had significantly induced level of essential amino acids, seems suitable for cultivation in moderately As contaminated soil and would be safe for human consumption.

Climate change (elevated CO₂, elevated temperature and moderate drought) triggers the antioxidant enzymes' response of grapevine cv. Tempranillo, avoiding oxidative damage.

PubMed

Salazar-Parra, Carolina; Aguirreolea, Jone; Sánchez-Díaz, Manuel; Irigoyen, Juan José; Morales, Fermín

2012-02-01

Photosynthetic carbon fixation (A(N) ) and photosynthetic electron transport rate (ETR) are affected by different environmental stress factors, such as those associated with climate change. Under stress conditions, it can be generated an electron excess that cannot be consumed, which can react with O₂, producing reactive oxygen species. This work was aimed to evaluate the influence of climate change (elevated CO₂, elevated temperature and moderate drought) on the antioxidant status of grapevine (Vitis vinifera) cv. Tempranillo leaves, from veraison to ripeness. The lowest ratios between electrons generated (ETR) and consumed (A(N) + respiration + photorespiration) were observed in plants treated with elevated CO₂ and elevated temperature. In partially irrigated plants under current ambient conditions, electrons not consumed seemed to be diverted to alternative ways. Oxidative damage to chlorophylls and carotenoids was not observed. However, these plants had increases in thiobarbituric acid reacting substances, an indication of lipid peroxidation. These increases matched well with an early rise of H₂O₂ and antioxidant enzyme activities, superoxide dismutase (EC 1.15.1.1), ascorbate peroxidase (EC 1.11.1.11) and catalase (EC 1.11.1.6). Enzymatic activities were maintained high until ripeness. In conclusion, plants grown under current ambient conditions and moderate drought were less efficient to cope with oxidative damage than well-irrigated plants, and more interestingly, plants grown under moderate drought but treated with elevated CO₂ and elevated temperature were not affected by oxidative damage, mainly because of higher rates of electrons consumed in photosynthetic carbon fixation. Copyright © Physiologia Plantarum 2011.

Ascorbate Peroxidase and Catalase Activities and Their Genetic Regulation in Plants Subjected to Drought and Salinity Stresses.

PubMed

Sofo, Adriano; Scopa, Antonio; Nuzzaci, Maria; Vitti, Antonella

2015-06-12

Hydrogen peroxide (H2O2), an important relatively stable non-radical reactive oxygen species (ROS) is produced by normal aerobic metabolism in plants. At low concentrations, H2O2 acts as a signal molecule involved in the regulation of specific biological/physiological processes (photosynthetic functions, cell cycle, growth and development, plant responses to biotic and abiotic stresses). Oxidative stress and eventual cell death in plants can be caused by excess H2O2 accumulation. Since stress factors provoke enhanced production of H2O2 in plants, severe damage to biomolecules can be possible due to elevated and non-metabolized cellular H2O2. Plants are endowed with H2O2-metabolizing enzymes such as catalases (CAT), ascorbate peroxidases (APX), some peroxiredoxins, glutathione/thioredoxin peroxidases, and glutathione sulfo-transferases. However, the most notably distinguished enzymes are CAT and APX since the former mainly occurs in peroxisomes and does not require a reductant for catalyzing a dismutation reaction. In particular, APX has a higher affinity for H2O2 and reduces it to H2O in chloroplasts, cytosol, mitochondria and peroxisomes, as well as in the apoplastic space, utilizing ascorbate as specific electron donor. Based on recent reports, this review highlights the role of H2O2 in plants experiencing water deficit and salinity and synthesizes major outcomes of studies on CAT and APX activity and genetic regulation in drought- and salt-stressed plants.

Ascorbate Peroxidase and Catalase Activities and Their Genetic Regulation in Plants Subjected to Drought and Salinity Stresses

PubMed Central

Sofo, Adriano; Scopa, Antonio; Nuzzaci, Maria; Vitti, Antonella

2015-01-01

Hydrogen peroxide (H2O2), an important relatively stable non-radical reactive oxygen species (ROS) is produced by normal aerobic metabolism in plants. At low concentrations, H2O2 acts as a signal molecule involved in the regulation of specific biological/physiological processes (photosynthetic functions, cell cycle, growth and development, plant responses to biotic and abiotic stresses). Oxidative stress and eventual cell death in plants can be caused by excess H2O2 accumulation. Since stress factors provoke enhanced production of H2O2 in plants, severe damage to biomolecules can be possible due to elevated and non-metabolized cellular H2O2. Plants are endowed with H2O2-metabolizing enzymes such as catalases (CAT), ascorbate peroxidases (APX), some peroxiredoxins, glutathione/thioredoxin peroxidases, and glutathione sulfo-transferases. However, the most notably distinguished enzymes are CAT and APX since the former mainly occurs in peroxisomes and does not require a reductant for catalyzing a dismutation reaction. In particular, APX has a higher affinity for H2O2 and reduces it to H2O in chloroplasts, cytosol, mitochondria and peroxisomes, as well as in the apoplastic space, utilizing ascorbate as specific electron donor. Based on recent reports, this review highlights the role of H2O2 in plants experiencing water deficit and salinity and synthesizes major outcomes of studies on CAT and APX activity and genetic regulation in drought- and salt-stressed plants. PMID:26075872

Ascorbic Acid-A Potential Oxidant Scavenger and Its Role in Plant Development and Abiotic Stress Tolerance

PubMed Central

Akram, Nudrat A.; Shafiq, Fahad; Ashraf, Muhammad

2017-01-01

Over-production of reactive oxygen species (ROS) in plants under stress conditions is a common phenomenon. Plants tend to counter this problem through their ability to synthesize ROS neutralizing substances including non-enzymatic and enzymatic antioxidants. In this context, ascorbic acid (AsA) is one of the universal non-enzymatic antioxidants having substantial potential of not only scavenging ROS, but also modulating a number of fundamental functions in plants both under stress and non-stress conditions. In the present review, the role of AsA, its biosynthesis, and cross-talk with different hormones have been discussed comprehensively. Furthermore, the possible involvement of AsA-hormone crosstalk in the regulation of several key physiological and biochemical processes like seed germination, photosynthesis, floral induction, fruit expansion, ROS regulation and senescence has also been described. A simplified and schematic AsA biosynthetic pathway has been drawn, which reflects key intermediates involved therein. This could pave the way for future research to elucidate the modulation of plant AsA biosynthesis and subsequent responses to environmental stresses. Apart from discussing the role of different ascorbate peroxidase isoforms, the comparative role of two key enzymes, ascorbate peroxidase (APX) and ascorbate oxidase (AO) involved in AsA metabolism in plant cell apoplast is also discussed particularly focusing on oxidative stress perception and amplification. Limited progress has been made so far in terms of developing transgenics which could over-produce AsA. The prospects of generation of transgenics overexpressing AsA related genes and exogenous application of AsA have been discussed at length in the review. PMID:28491070

Computational Study of the Bulk Properties of a Novel Molecule: alpha-Tocopherol-Ascorbic Acid Surfactant

NASA Astrophysics Data System (ADS)

Stirling, Shannon; Kim, Hye-Young

Alpha-tocopherol-ascorbic acid surfactant (EC) is a novel amphiphilic molecule of antioxidant properties, which has a hydrophobic vitamin E and a hydrophilic vitamin C chemically linked. We have developed atomistic force fields (g54a7) for a protonated (neutral) EC molecule. Our goal is to carry out molecular dynamics (MD) simulations of protonated EC molecules using the newly developed force fields and study the molecular properties. First we ran energy minimization (EM) with one molecule in a vacuum to obtain the low energy molecular configuration with emtol =10. We then used Packmol to insert 125 EC molecules in a 3nm cube. We then performed MD simulations of the bulk system composed of 125 EC molecules, from which we measured the bulk density and the evaporation energy of the molecular system. Gromacs2016 is used for the EM and MD simulation studies. We will present the results of the ongoing research. National Institute Of General Medical Sciences of the National Institutes of Health under Award Number P20GM103424 (Kim). Computational resources were provided by the Louisiana Optical Network Initiative.

Impact of Oxidative Stress on Ascorbate Biosynthesis in Chlamydomonas via Regulation of the VTC2 Gene Encoding a GDP-l-galactose Phosphorylase*

PubMed Central

Urzica, Eugen I.; Adler, Lital N.; Page, M. Dudley; Linster, Carole L.; Arbing, Mark A.; Casero, David; Pellegrini, Matteo; Merchant, Sabeeha S.; Clarke, Steven G.

2012-01-01

The l-galactose (Smirnoff-Wheeler) pathway represents the major route to l-ascorbic acid (vitamin C) biosynthesis in higher plants. Arabidopsis thaliana VTC2 and its paralogue VTC5 function as GDP-l-galactose phosphorylases converting GDP-l-galactose to l-galactose-1-P, thus catalyzing the first committed step in the biosynthesis of l-ascorbate. Here we report that the l-galactose pathway of ascorbate biosynthesis described in higher plants is conserved in green algae. The Chlamydomonas reinhardtii genome encodes all the enzymes required for vitamin C biosynthesis via the l-galactose pathway. We have characterized recombinant C. reinhardtii VTC2 as an active GDP-l-galactose phosphorylase. C. reinhardtii cells exposed to oxidative stress show increased VTC2 mRNA and l-ascorbate levels. Genes encoding enzymatic components of the ascorbate-glutathione system (e.g. ascorbate peroxidase, manganese superoxide dismutase, and dehydroascorbate reductase) are also up-regulated in response to increased oxidative stress. These results indicate that C. reinhardtii VTC2, like its plant homologs, is a highly regulated enzyme in ascorbate biosynthesis in green algae and that, together with the ascorbate recycling system, the l-galactose pathway represents the major route for providing protective levels of ascorbate in oxidatively stressed algal cells. PMID:22393048

Effects of 24-epibrassinolide on enzymatic browning and antioxidant activity of fresh-cut lotus root slices.

PubMed

Gao, Hui; Chai, HongKang; Cheng, Ni; Cao, Wei

2017-02-15

Fresh-cut lotus root slices were treated with 80nM 24-epibrassinolide (EBR) and then stored at 4°C for 8days to investigate the effects on cut surface browning. The results showed that EBR treatment reduced cut surface browning in lotus root slices and alleviated membrane lipid peroxidation as reflected by low malondialdehyde content and lipoxygenase activity. EBR treatment inhibited the activity of phenylalanine ammonia lyase and polyphenol oxidase, and subsequently decreased phenolics accumulation and soluble quniones formation. The treatment also stimulated the activity of peroxidase, catalase and ascorbate peroxidase and delayed the loss of ascorbic acid, which would help prevent membrane lipid peroxidation, as a consequence, reducing decompartmentation of enzymes and substrates causing enzymatic browning. These results indicate that EBR treatment is a promising attempt to control browning at cut surface of fresh-cut lotus root slices. Copyright © 2016 Elsevier Ltd. All rights reserved.

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

PubMed

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 proved that rice cultivar Kanchana respond to different environmental signals independently and tolerance mechanisms to individual stress factors was also varied. Copyright © 2017 Elsevier B.V. All rights reserved.

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

PubMed

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.

Glyphosate-Dependent Inhibition of Photosynthesis in Willow.

PubMed

Gomes, Marcelo P; Le Manac'h, Sarah G; Hénault-Ethier, Louise; Labrecque, Michel; Lucotte, Marc; Juneau, Philippe

2017-01-01

We studied the physiological mechanisms involved in the deleterious effects of a glyphosate-based herbicide (Factor ® 540) on photosynthesis and related physiological processes of willow ( Salix miyabeana cultivar SX64) plants. Sixty-day-old plants grown under greenhouse conditions were sprayed with different rates (0, 1.4, 2.1, and 2.8 kg a.e ha -1 ) of the commercial glyphosate formulated salt Factor ® 540. Evaluations were performed at 0, 6, 24, 48, and 72 h after herbicide exposure. We established that the herbicide decreases chlorophyll, carotenoid and plastoquinone contents, and promotes changes in the photosynthetic apparatus leading to decreased photochemistry which results in hydrogen peroxide (H 2 O 2 ) accumulation. H 2 O 2 accumulation triggers proline production which can be associated with oxidative protection, NADP + recovery and shikimate pathway stimulation. Ascorbate peroxidase and glutathione peroxidase appeared to be the main peroxidases involved in the H 2 O 2 scavenging. In addition to promoting decreases of the activity of the antioxidant enzymes, the herbicide induced decreases in ascorbate pool. For the first time, a glyphosate-based herbicide mode of action interconnecting its effects on shikimate pathway, photosynthetic process and oxidative events in plants were presented.

Glyphosate-Dependent Inhibition of Photosynthesis in Willow

PubMed Central

Gomes, Marcelo P.; Le Manac’h, Sarah G.; Hénault-Ethier, Louise; Labrecque, Michel; Lucotte, Marc; Juneau, Philippe

2017-01-01

We studied the physiological mechanisms involved in the deleterious effects of a glyphosate-based herbicide (Factor® 540) on photosynthesis and related physiological processes of willow (Salix miyabeana cultivar SX64) plants. Sixty-day-old plants grown under greenhouse conditions were sprayed with different rates (0, 1.4, 2.1, and 2.8 kg a.e ha-1) of the commercial glyphosate formulated salt Factor® 540. Evaluations were performed at 0, 6, 24, 48, and 72 h after herbicide exposure. We established that the herbicide decreases chlorophyll, carotenoid and plastoquinone contents, and promotes changes in the photosynthetic apparatus leading to decreased photochemistry which results in hydrogen peroxide (H2O2) accumulation. H2O2 accumulation triggers proline production which can be associated with oxidative protection, NADP+ recovery and shikimate pathway stimulation. Ascorbate peroxidase and glutathione peroxidase appeared to be the main peroxidases involved in the H2O2 scavenging. In addition to promoting decreases of the activity of the antioxidant enzymes, the herbicide induced decreases in ascorbate pool. For the first time, a glyphosate-based herbicide mode of action interconnecting its effects on shikimate pathway, photosynthetic process and oxidative events in plants were presented. PMID:28261257

Combined Effects of Lanthanum (III) and Acid Rain on Antioxidant Enzyme System in Soybean Roots.

PubMed

Zhang, Xuanbo; Du, Yuping; Wang, Lihong; Zhou, Qing; Huang, Xiaohua; Sun, Zhaoguo

2015-01-01

Rare earth element pollution (REEs) and acid rain (AR) pollution simultaneously occur in many regions, which resulted in a new environmental issue, the combined pollution of REEs and AR. The effects of the combined pollution on the antioxidant enzyme system of plant roots have not been reported. Here, the combined effects of lanthanum ion (La3+), one type of REE, and AR on the antioxidant enzyme system of soybean roots were investigated. In the combined treatment of La3+ (0.08 mM) and AR, the cell membrane permeability and the peroxidation of cell membrane lipid of soybean roots increased, and the superoxide dismutase, catalase, peroxidase and reduced ascorbic acid served as scavengers of reactive oxygen species. In other combined treatments of La3+ (0.40 mM, 1.20 mM) and AR, the membrane permeability, malonyldialdehyde content, superoxide dismutase activity, peroxidase activity and reduced ascorbic acid content increased, while the catalase activity decreased. The increased superoxide dismutase activity, peroxidase activity and reduced ascorbic acid content were inadequate to scavenge the excess hydrogen peroxide and superoxide, leading to the damage of the cell membrane, which was aggravated with the increase in the concentration of La3+ and the level of AR. The deleterious effects of the combined treatment of La3+ and AR were stronger than those of the single treatment of La3+ or AR. Moreover, the activity of antioxidant enzyme system in the combined treatment group was affected directly and indirectly by mineral element content in soybean plants.

Combined Effects of Lanthanum (III) and Acid Rain on Antioxidant Enzyme System in Soybean Roots

PubMed Central

Zhang, Xuanbo; Du, Yuping; Wang, Lihong; Zhou, Qing; Huang, Xiaohua; Sun, Zhaoguo

2015-01-01

Rare earth element pollution (REEs) and acid rain (AR) pollution simultaneously occur in many regions, which resulted in a new environmental issue, the combined pollution of REEs and AR. The effects of the combined pollution on the antioxidant enzyme system of plant roots have not been reported. Here, the combined effects of lanthanum ion (La3+), one type of REE, and AR on the antioxidant enzyme system of soybean roots were investigated. In the combined treatment of La3+ (0.08 mM) and AR, the cell membrane permeability and the peroxidation of cell membrane lipid of soybean roots increased, and the superoxide dismutase, catalase, peroxidase and reduced ascorbic acid served as scavengers of reactive oxygen species. In other combined treatments of La3+ (0.40 mM, 1.20 mM) and AR, the membrane permeability, malonyldialdehyde content, superoxide dismutase activity, peroxidase activity and reduced ascorbic acid content increased, while the catalase activity decreased. The increased superoxide dismutase activity, peroxidase activity and reduced ascorbic acid content were inadequate to scavenge the excess hydrogen peroxide and superoxide, leading to the damage of the cell membrane, which was aggravated with the increase in the concentration of La3+ and the level of AR. The deleterious effects of the combined treatment of La3+ and AR were stronger than those of the single treatment of La3+ or AR. Moreover, the activity of antioxidant enzyme system in the combined treatment group was affected directly and indirectly by mineral element content in soybean plants. PMID:26230263

Antioxidant poly(lactic-co-glycolic) acid nanoparticles made with α-tocopherol-ascorbic acid surfactant.

PubMed

Astete, Carlos E; Dolliver, Debra; Whaley, Meocha; Khachatryan, Lavrent; Sabliov, Cristina M

2011-12-27

The goal of the study was to synthesize a surfactant made of α-tocopherol (vitamin E) and ascorbic acid (vitamin C) of antioxidant properties dubbed as EC, and to use this surfactant to make poly(lactic-co-glycolic) acid (PLGA) nanoparticles. Self-assembled EC nanostructures and PLGA-EC nanoparticles were made by nanoprecipitation, and their physical properties (size, size distribution, morphology) were studied at different salt concentrations, surfactant concentrations, and polymer/surfactant ratios. EC surfactant was shown to form self-assembled nanostructures in water with a size of 22 to 138 nm in the presence of sodium chloride, or 12 to 31 nm when synthesis was carried out in sodium bicarbonate. Polymeric PLGA-EC nanoparticles presented a size of 90 to 126 nm for 40% to 120% mass ratio PLGA to surfactant. For the same mass ratios, the PLGA-Span80 formed particles measured 155 to 216 nm. Span80 formed bilayers, whereas EC formed monolayers at the interfaces. PLGA-EC nanoparticles and EC showed antioxidant activity based on 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay measurements using UV and EPR techniques, antioxidant activity which is not characteristic to commercially available Span80. The thiobarbituric acid reactive substances (TBARS) assay for lipid peroxidation showed that PLGA nanoparticles with EC performed better as antioxidants than the EC nanoassembly or the free vitamin C. Nanoparticles were readily internalized by HepG2 cells and were localized in the cytoplasm. The newly synthesized EC surfactant was therefore found successful in forming uniform, small size polymeric nanoparticles of intrinsic antioxidant properties.

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Günther, T-hat nia Mara Fischer; Kviecinski, Maicon Roberto; Baron, Carla Cristine

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 notmore » 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.« less

Effect of Chitosan Coating on the Postharvest Quality and Antioxidant Enzyme System Response of Strawberry Fruit during Cold Storage

PubMed Central

Petriccione, Milena; Mastrobuoni, Francesco; Pasquariello, Maria Silvia; Zampella, Luigi; Nobis, Elvira; Capriolo, Giuseppe; Scortichini, Marco

2015-01-01

The effectiveness of chitosan fruit coating to delay the qualitative and nutraceutical traits of three strawberry cultivars, namely “Candonga”, “Jonica” and “Sabrina”, as well as the effects of chitosan on antioxidant enzymes were evaluated. The fruits were coated with 1% and 2% chitosan solution and stored at 2 °C for nine days. Samples were taken every three days. Physico-chemical (weight loss, soluble solid content and titratable acidity) and nutraceutical (total polyphenol, anthocyanin, flavonoid, ascorbic acid content and antioxidant capacity) properties along with the enzymatic activity (catalase (CAT), ascorbate peroxidase (APX), polyphenol oxidase (PPO), guaiacol peroxidase (GPX) and lipoxygenase (LOX)) were evaluated. Chitosan treatment significantly reduced water loss and delayed the qualitative changes in color, titratable acidity and ascorbic acid content in dose- and cultivar-dependent manners. Additionally, changes in the total polyphenol, anthocyanin and flavonoid contents and the antioxidant capacity of chitosan-coated strawberry fruits were delayed. Chitosan coating enhanced the activity of some antioxidant enzymes, preventing flesh browning and reducing membrane damage. A global view of the responses of the three strawberry cultivars to chitosan coating and storage temperature was obtained using principal component analysis. Chitosan-coated fruit exhibited a slower rate of deterioration, compared to uncoated fruit in all tested cultivars. PMID:28231220

Cytokinin oxidase/dehydrogenase overexpression modifies antioxidant defense against heat, drought and their combination in Nicotiana tabacum plants.

PubMed

Lubovská, Zuzana; Dobrá, Jana; Storchová, Helena; Wilhelmová, Naďa; Vanková, Radomíra

2014-11-01

Cytokinins (CKs) as well as the antioxidant enzyme system (AES) play important roles in plant stress responses. The expression and activity of antioxidant enzymes (AE) were determined in drought, heat and combination of both stresses, comparing the response of tobacco plants overexpressing the main cytokinin degrading enzyme, cytokinin oxidase/dehydrogenase, under the control of root-specific WRKY6 promoter (W6:CKX1 plants) or constitutive promoter (35S:CKX1 plants) and the corresponding wild-type (WT). Expression levels as well as activities of cytosolic ascorbate peroxidase, catalase 3, and cytosolic superoxide dismutase were low under optimal conditions and increased after heat and combined stress in all genotypes. Unlike catalase 3, two other peroxisomal enzymes, catalase 1 and catalase 2, were transcribed extensively under control conditions. Heat stress, in contrast to drought or combined stress, increased catalase 1 and reduced catalase 2 expression in WT and W6:CKX1 plants. In 35S:CKX1, catalase 1 expression was enhanced by heat or drought, but not under combined stress conditions. Mitochondrial superoxide dismutase expression was generally higher in 35S:CKX1 plants than in WT. Genes encoding for chloroplastic AEs, stromatal ascorbate peroxidase, thylakoidal ascorbate peroxidase and chloroplastic superoxide dismutase, were strongly transcribed under control conditions. All stresses down-regulated their expression in WT and W6:CKX1, whereas more stress-tolerant 35S:CKX1 plants maintained high expression during drought and heat. The achieved data show that the effect of down-regulation of CK levels on AES may be mediated by altered habit, resulting in improved stress tolerance, which is associated with diminished stress impact on photosynthesis, and changes in source/sink relations. Copyright © 2014 Elsevier GmbH. All rights reserved.

Photosynthetic and antioxidant responses of Liquidambar formosana and Schima superba seedlings to sulfuric-rich and nitric-rich simulated acid rain.

PubMed

Chen, Juan; Wang, Wen-Hua; Liu, Ting-Wu; Wu, Fei-Hua; Zheng, Hai-Lei

2013-03-01

To study whether differential responses occur in photosynthesis and antioxidant system for seedlings of Liquidambar formosana, an acid rain (AR)-sensitive tree species and Schima superba, an AR-tolerant tree species treated with three types of pH 3.0 simulated AR (SiAR) including sulfuric-rich (S-SiAR), nitric-rich (N-SiAR), sulfate and nitrate mixed (SN-SiAR), we investigated the changes of leaf necrosis, chlorophyll content, soluble protein and proline content, photosynthesis and chlorophyll fluorescence characteristics, reactive oxygen species production, membrane lipid peroxidation, small molecular antioxidant content, antioxidant enzyme activities and related protein expressions. Our results showed that SiAR significantly caused leaf necrosis, inhibited photosynthesis, induced superoxide radical and hydrogen peroxide generation, aggravated membrane lipid peroxidation, changed antioxidant enzyme activities, modified related protein expressions such as Cu/Zn superoxide dismutase (SOD), l-ascorbate peroxidase (APX, EC 1. 11. 1. 11), glutathione S transferase (GST, EC 2. 5. 1. 18) and Rubisco large subunit (RuBISCO LSU), altered non-protein thiols (NPT) and glutathione (GSH) content in leaves of L. formosana and S. superba. Taken together, we concluded that the damages caused by SiAR in L. formosana were more severe and suffered from more negative impacts than in S. superba. S-SiAR induced more serious damages for the plants than did SN-SiAR and N-SiAR. Crown Copyright © 2013. Published by Elsevier Masson SAS. All rights reserved.

Kinetics, subcellular localization, and contribution to parasite virulence of a Trypanosoma cruzi hybrid type A heme peroxidase (TcAPx-CcP)

PubMed Central

Hugo, Martín; Martínez, Alejandra; Trujillo, Madia; Estrada, Damián; Mastrogiovanni, Mauricio; Linares, Edlaine; Augusto, Ohara; Issoglio, Federico; Zeida, Ari; Estrín, Darío A.; Heijnen, Harry F. G.; Piacenza, Lucía; Radi, Rafael

2017-01-01

The Trypanosoma cruzi ascorbate peroxidase is, by sequence analysis, a hybrid type A member of class I heme peroxidases [TcAPx-cytochrome c peroxidase (CcP)], suggesting both ascorbate (Asc) and cytochrome c (Cc) peroxidase activity. Here, we show that the enzyme reacts fast with H2O2 (k = 2.9 × 107 M−1⋅s−1) and catalytically decomposes H2O2 using Cc as the reducing substrate with higher efficiency than Asc (kcat/Km = 2.1 × 105 versus 3.5 × 104 M−1⋅s−1, respectively). Visible-absorption spectra of purified recombinant TcAPx-CcP after H2O2 reaction denote the formation of a compound I-like product, characteristic of the generation of a tryptophanyl radical-cation (Trp233•+). Mutation of Trp233 to phenylalanine (W233F) completely abolishes the Cc-dependent peroxidase activity. In addition to Trp233•+, a Cys222-derived radical was identified by electron paramagnetic resonance spin trapping, immunospin trapping, and MS analysis after equimolar H2O2 addition, supporting an alternative electron transfer (ET) pathway from the heme. Molecular dynamics studies revealed that ET between Trp233 and Cys222 is possible and likely to participate in the catalytic cycle. Recognizing the ability of TcAPx-CcP to use alternative reducing substrates, we searched for its subcellular localization in the infective parasite stages (intracellular amastigotes and extracellular trypomastigotes). TcAPx-CcP was found closely associated with mitochondrial membranes and, most interestingly, with the outer leaflet of the plasma membrane, suggesting a role at the host–parasite interface. TcAPx-CcP overexpressers were significantly more infective to macrophages and cardiomyocytes, as well as in the mouse model of Chagas disease, supporting the involvement of TcAPx-CcP in pathogen virulence as part of the parasite antioxidant armamentarium. PMID:28179568

Peroxidase enzymes regulate collagen extracellular matrix biosynthesis.

PubMed

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.

The response of the foliar antioxidant system and stable isotopes (δ(13)C and δ(15)N) of white willow to low-level air pollution.

PubMed

Wuytack, Tatiana; AbdElgawad, Hamada; Staelens, Jeroen; Asard, Han; Boeckx, Pascal; Verheyen, Kris; Samson, Roeland

2013-06-01

In this study we aimed to determine and elucidate the effect of ambient air pollution on the foliar antioxidant system and stable carbon and nitrogen isotopes of white willow (Salix alba L.). We grew white willow in uniform potting soil in the near vicinity of sixteen air quality monitoring stations in Belgium where nitrogen dioxide (NO2), ozone, sulfur dioxide and particulate matter concentrations were continuously measured. The trees were exposed to ambient air during six months (April-September 2011), and, thereafter, the degree of lipid peroxidation and foliar content of antioxidant molecules (ascorbate, glutathione, polyphenols, flavonoids), antioxidant enzymes (superoxide dismutase, ascorbate peroxidase, peroxidase) and foliar stable carbon (δ(13)C) and nitrogen (δ(15)N) isotopes were measured. We found that lipid peroxidation was caused by air pollution stress, arising from high ambient NO2 concentrations, as shown by an increased amount of malondialdehyde. The antioxidant system was activated by increasing the amount of polyphenols at monitoring stations with a high atmospheric NO2 and low O3 concentration, while no increase of key enzymes (e.g., ascorbate, glutathione) was observed. The δ(13)C also decreased with increasing NO2 concentrations and decreasing O3 concentrations, probably reflecting a decreased net photosynthesis and/or a concomitant decrease of (13)CO2 in the atmosphere. Shade also influenced foliar δ(13)C and the content of leaf ascorbate and glutathione. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

Antioxidant enzymes activity and phenolic compounds content in red cabbage seedlings exposed to copper stress.

PubMed

Posmyk, M M; Kontek, R; Janas, K M

2009-02-01

The phenolics: anthocyanin (ATH), sinapoyl esters and activity of antioxidant enzymes: superoxide dismutase (SOD), catalase (CAT), guaiacol peroxidase (POX), ascorbate peroxidase (APX), glutathione peroxidase (GPX) and glutathione reductase (GR), in red cabbage seedlings subjected to Cu2+ stress were investigated. Cu2+ at low doses (0.5 mM), increased the levels of ATH and sinapoyl derivatives in red cabbage. High Cu2+ concentration (2.5 mM) provoked oxidative stress and enhanced thiobarbituric acid reactive substances (TBARS) content in tissues. A lower level of TBARS was correlated with high ATH content. It seems that synthesis of these isoflavonoids is an effective strategy against reactive oxygen species (ROS). The analysis of the antioxidant enzymes activity suggested that peroxidases were the most active enzymes in red cabbage seedlings exposed to Cu2+ stress. It could results from the fact that phenolic compounds (PhC), which could be also substrates for different peroxidases, were the first line of defence against metal stress.

Spatial organization of silybin biosynthesis in milk thistle [Silybum marianum (L.) Gaertn].

PubMed

Lv, Yongkun; Gao, Song; Xu, Sha; Du, Guocheng; Zhou, Jingwen; Chen, Jian

2017-12-01

Silymarin is a collection of compounds extracted from the medicinal herb milk thistle, among which silybin is the major flavonolignan. However, the biosynthesis pathway of silybin remains unclear. In this study, biomimetic reactions demonstrated that silybin can be synthesized from coniferyl alcohol and taxifolin by the action of peroxidase. The concentration profiles of silybin and its precursors and RNA-Seq analysis of gene expression revealed that the amount of taxifolin and the activity of peroxidase serve as the limiting factors in silybin biosynthesis. Hierarchical clustering of the expression profile of genes of the flavonoid biosynthesis pathway distinguished flowers from other organs. RNA-Seq revealed five candidates for the peroxidase involved in silybin production, among which APX1 (ascorbate peroxidase 1) showed a distinct peroxidase activity and the capacity to synthesize silybin. The spatial organization of silybin biosynthesis in milk thistle was elucidated, which could help our understanding of the biosynthesis of silybin and other flavonolignans. © 2017 The Authors The Plant Journal © 2017 John Wiley & Sons Ltd.

Ascorbic acid metabolism during sweet cherry (Prunus avium) fruit development

PubMed Central

Ni, Zhiyou; Lin, Lijin; Tang, Yi; Wang, Zhihui; Wang, Xun; Wang, Jin; Lv, Xiulan; Xia, Hui

2017-01-01

To elucidate metabolism of ascorbic acid (AsA) in sweet cherry fruit (Prunus avium ‘Hongdeng’), we quantified AsA concentration, cloned sequences involved in AsA metabolism and investigated their mRNA expression levels, and determined the activity levels of selected enzymes during fruit development and maturation. We found that AsA concentration was highest at the petal-fall period (0 days after anthesis) and decreased progressively during ripening, but with a slight increase at maturity. AsA did nevertheless continue to accumulate over time because of the increase in fruit fresh weight. Full-length cDNAs of 10 genes involved in the L-galactose pathway of AsA biosynthesis and 10 involved in recycling were obtained. Gene expression patterns of GDP-L-galactose phosphorylase (GGP2), L-galactono-1, 4-lactone dehydrogenase (GalLDH), ascorbate peroxidase (APX3), ascorbate oxidase (AO2), glutathione reductase (GR1), and dehydroascorbate reductase (DHAR1) were in accordance with the AsA concentration pattern during fruit development, indicating that genes involved in ascorbic acid biosynthesis, degradation, and recycling worked in concert to regulate ascorbic acid accumulation in sweet cherry fruit. PMID:28245268

Peroxidase Enzymes Regulate Collagen Biosynthesis and Matrix Mineralization by Cultured Human Osteoblasts.

PubMed

DeNichilo, Mark O; Shoubridge, Alexandra J; Panagopoulos, Vasilios; Liapis, Vasilios; Zysk, Aneta; Zinonos, Irene; Hay, Shelley; Atkins, Gerald J; Findlay, David M; Evdokiou, Andreas

2016-03-01

The early recruitment of inflammatory cells to sites of bone fracture and trauma is a critical determinant in successful fracture healing. Released by infiltrating inflammatory cells, myeloperoxidase (MPO) and eosinophil peroxidase (EPO) are heme-containing enzymes, whose functional involvement in bone repair has mainly been studied in the context of providing a mechanism for oxidative defense against invading microorganisms. We report here novel findings that show peroxidase enzymes have the capacity to stimulate osteoblastic cells to secrete collagen I protein and generate a mineralized extracellular matrix in vitro. Mechanistic studies conducted using cultured osteoblasts show that peroxidase enzymes stimulate collagen biosynthesis at a post-translational level in a prolyl hydroxylase-dependent manner, which does not require ascorbic acid. Our studies demonstrate that osteoblasts rapidly bind and internalize both MPO and EPO, and the catalytic activity of these peroxidase enzymes is essential to support collagen I biosynthesis and subsequent release of collagen by osteoblasts. We show that EPO is capable of regulating osteogenic gene expression and matrix mineralization in culture, suggesting that peroxidase enzymes may play an important role not only in normal bone repair, but also in the progression of pathological states where infiltrating inflammatory cells are known to deposit peroxidases.

Effects of Acifluorfen on Endogenous Antioxidants and Protective Enzymes in Cucumber (Cucumis sativus L.) Cotyledons

PubMed Central

Kenyon, William H.; Duke, Stephen O.

1985-01-01

The herbicide acifluorfen (2-chloro-4-(trifluoromethyl)phenoxy-2-nitrobenzoate) causes strong photooxidative destruction of pigments and lipids in sensitive plant species. Antioxidants and oxygen radical scavengers slow the bleaching action of the herbicide. The effect of acifluorfen on glutathione and ascorbate levels in cucumber (Cucumis sativus L.) cotyledon discs was investigated to assess the relationship between herbicide activity and endogenous antioxidants. Acifluorfen decreased the levels of glutathione and ascorbate over 50% in discs exposed to less than 1.5 hours of white light (450 microeinsteins per square meter per second). Coincident increases in dehydroascorbate and glutathione disulfide were not observed. Acifluorfen also caused the rapid depletion of ascorbate in far-red light grown plants which were photosynthetically incompetent. Glutathione reductase, dehydroascorbate reductase, superoxide dismutase, ascorbate oxidase, ascorbate free radical reductase, peroxidase, and catalase activities rapidly decreased in acifluorfen-treated tissue exposed to white light. None of the enzymes were inhibited in vitro by the herbicide. Acifluorfen causes irreversible photooxidative destruction of plant tissue, in part, by depleting endogenous antioxidants and inhibiting the activities of protective enzymes. PMID:16664506

Effect of natural antibrowning agents on color and related enzymes in fresh-cut Fuji apples as an alternative to the use of ascorbic acid.

PubMed

Rojas-Graü, M A; Soliva-Fortuny, R; Niartín-Belloso, O

2008-08-01

Polyphenoloxidase (PPO) and peroxidase (POD) were evaluated in fresh-cut Fuji apple slices and the effeet of the individual or combined use of ascorbic acid, 4-hexylresorcinol, N-acetylcysteine, and glutathione on their respective activities was determined. Additionally, color changes during storage at 4 degrees C were measured throughout 14 d of storage. PPO activity increased with storage time and was inhibited by the individual use of N-acetylcysteine and glutathione. POD activity in the apple slices was effectively inhibited by the combined use of ascorbic acid with any of the other antibrowning agents. On the other hand, an individual treatment with 1% N-acetylcysteine helped in maintaining the color of fresh-cut apples during 14 d of storage, whereas the use of ascorbic acid was not enough to prevent color deterioration of the apple slices from the 1st day of storage. The results obtained corroborated the effectiveness of other natural antibrowning agents over the traditional use of ascorbic acid in the control of the enzymatic browning in the fresh-cut fruit industry.

Activities of some enzymes of lignin formation in reaction wood of Thuja orientalis, Metasequoia glyptostroboides and Robinia pseudoacacia.

PubMed

Kutsuki, H; Higuchi, T

1981-07-01

The activities of the following five enzymes which are involved in the formation of lignin have been compared in reaction wood and in opposite wood: phenylalanine ammonia lyase (EC 4.3.1.5), caffeate 3-O-methyltransferase (EC 2.1.1.-), p-hydroxycinnamate: CoA ligase (EC 6.2.1.12), cinnamyl alcohol dehydrogenase (EC 1.1.1.-) and peroxidase (EC 1.11.1.7). The activities of the four first-named enzymes in the compression wood of Thuja orientalis L. and Metasequoia glyptostroboides Hu et Cheng were 2.8±1.4-fold and 2.6±1.5-fold higher than those in opposite wood, respectively, whereas peroxidase had the same level of activity in either type of wood. On the other hand, no differences were observed in the activities of the five enzymes between tension and opposite woods of Robinia pseudoacacia L. These findings are well in accord with the chemical structure of lignin in the compression and tension woods of the three species studied: high content of lignin rich in condensed units in compression wood, and little difference in lignin between tension and opposite woods.

Alterations in antioxidant defense system of workers chronically exposed to arsenic, cadmium and mercury from coal flying ash.

PubMed

Zeneli, Lulzim; Sekovanić, Ankica; Ajvazi, Majlinda; Kurti, Leonard; Daci, Nexhat

2016-02-01

Humans are exposed to different stress factors that are responsible for over-production of reactive oxygen species. Exposure to heavy metals is one of these factors. The aim of the study was to analyze the effect of chronic exposure to heavy metals through coal flying ash on the efficiency of antioxidative defensive mechanisms, represented by the activity of superoxide dismutase, glutathione peroxidase and ascorbic acid. Nonessential elements such as arsenic and mercury levels showed a significant increase (p > 0.001) in the power plant workers rather than in the control subjects. There were no significant differences of blood cadmium between power plant workers and control subjects. We found a significant positive correlation (p < 0.05) between BAs/SZn (r = 0.211), BAs/BSe (r = 0.287), BCd/SCu (r = 0.32) and BHg/BSe (r = 0.263) in the plant workers. Red blood cell antioxidant enzymes and plasma ascorbic acid were significantly lower in power plants workers than in the control group (p < 0.002). We can conclude that levels of mercury, arsenic and cadmium in blood, despite their concentration within the reference values, significantly affect plasma ascorbic acid concentration, superoxide dismutase and glutathione peroxidase activity, which are able to increase the risk of oxidative stress.

Nitric oxide alleviates aluminum-induced oxidative damage through regulating the ascorbate-glutathione cycle in roots of wheat.

PubMed

Sun, Chengliang; Liu, Lijuan; Yu, Yan; Liu, Wenjing; Lu, Lingli; Jin, Chongwei; Lin, Xianyong

2015-06-01

The possible association with nitric oxide (NO) and ascorbate-glutathione (AsA-GSH) cycle in regulating aluminum (Al) tolerance of wheat (Triticum aestivum L.) was investigated using two genotypes with different Al resistance. Exposure to Al inhibited root elongation, and triggered lipid peroxidation and oxidation of AsA to dehydroascorbate and GSH to glutathione disulfide in wheat roots. Exogenous NO significantly increased endogenous NO levels, and subsequently alleviated Al-induced inhibition of root elongation and oxidation of AsA and GSH to maintain the redox molecules in the reduced form in both wheat genotypes. Under Al stress, significantly increased activities and gene transcriptional levels of ascorbate peroxidase, glutathione reductase, and dehydroascorbate reductase, were observed in the root tips of the Al-tolerant genotype Jian-864. Nitric oxide application enhanced the activity and gene transcriptional level of these enzymes in both wheat genotypes. γ-Glutamylcysteine synthetase was not significantly affected by Al or NO, but NO treatments increased the activity of glutathione peroxidase and glutathione S-transferase to a greater extent than the Al-treated wheat seedlings. Proline was significantly decreased by Al, while it was not affected by NO. These results clearly suggest that NO protects wheat root against Al-induced oxidative stress, possibly through its regulation of the AsA-GSH cycle. © 2014 Institute of Botany, Chinese Academy of Sciences.

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

PubMed

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.

Ultraviolet-B component of sunlight stimulates photosynthesis and flavonoid accumulation in variegated Plectranthus coleoides leaves depending on background light.

PubMed

Vidović, Marija; Morina, Filis; Milić, Sonja; Zechmann, Bernd; Albert, Andreas; Winkler, Jana Barbro; Veljović Jovanović, Sonja

2015-05-01

We used variegated Plectranthus coleoides as a model plant with the aim of clarifying whether the effects of realistic ultraviolet-B (UV-B) doses on phenolic metabolism in leaves are mediated by photosynthesis. Plants were exposed to UV-B radiation (0.90 W m(-2) ) combined with two photosynthetically active radiation (PAR) intensities [395 and 1350 μmol m(-2)  s(-1) , low light (LL) and high light (HL)] for 9 d in sun simulators. Our study indicates that UV-B component of sunlight stimulates CO2 assimilation and stomatal conductance, depending on background light. UV-B-specific induction of apigenin and cyanidin glycosides was observed in both green and white tissues. However, all the other phenolic subclasses were up to four times more abundant in green leaf tissue. Caffeic and rosmarinic acids, catechin and epicatechin, which are endogenous peroxidase substrates, were depleted at HL in green tissue. This was correlated with increased peroxidase and ascorbate peroxidase activities and increased ascorbate content. The UV-B supplement to HL attenuated antioxidative metabolism and partly recovered the phenolic pool indicating stimulation of the phenylpropanoid pathway. In summary, we propose that ortho-dihydroxy phenolics are involved in antioxidative defence in chlorophyllous tissue upon light excess, while apigenin and cyanidin in white tissue have preferentially UV-screening function. © 2014 John Wiley & Sons Ltd.

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

PubMed

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.

Cerium Improves Growth of Maize Seedlings via Alleviating Morphological Structure and Oxidative Damages of Leaf under Different Stresses.

PubMed

Hong, Fashui; Qu, Chunxiang; Wang, Ling

2017-10-18

It had been indicated that cerium (Ce) could promote maize growth involving photosynthetic improvement under potassium (K) deficiency, salt stress, and combined stress of K + deficiency and salt stress. However, whether the improved growth is related to leaf morphological structure, oxidative stress in maize leaves is not well understood. The present study showed that K + deficiency, salt stress, and their combined stress inhibited growth of maize seedlings, affecting the formation of appendages of leaf epidermal cells, and stomatal opening, which may be due to increases in H 2 O 2 and malondialdehyde levels, and reductions in Ca 2+ content, ratios of glutathione/oxidized glutathione, ascorbic acid/dehydroascorbic acid, and the activities of superoxide dismutase, catalase, ascorbic acid peroxidase, guaiacol peroxidase, and glutathione reductase in leaves under different stresses. The adverse effects caused by combined stress were higher than those of single stress. Furthermore, our findings demonstrated that adding Ce 3+ could significantly promote seedling growth, and alleviate morphological and structural damage of leaf, decrease oxidative stress and increase antioxidative capacity in maize leaves caused by different stresses.

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

PubMed

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.

Reduction of methylviologen-mediated oxidative stress tolerance in antisense transgenic tobacco seedlings through restricted expression of StAPX.

PubMed

Sun, Wei-Hong; Wang, Yong; He, Hua-Gang; Li, Xue; Song, Wan; Du, Bin; Meng, Qing-Wei

2013-07-01

Ascorbate peroxidases are directly involved in reactive oxygen species (ROS) scavenging by reducing hydrogen peroxide to water. The tomato thylakoid-bound ascorbate peroxidase gene (StAPX) was introduced into tobacco. RNA gel blot analysis confirmed that StAPX in tomato leaves was induced by methylviologen-mediated oxidative stress. The sense transgenic seedlings exhibited higher tAPX activity than that of the wild type (WT) plants under oxidative stress conditions, while the antisense seedlings exhibited lower tAPX activity. Lower APX activities of antisense transgenic seedlings caused higher malondialdehyde contents and relative electrical conductivity. The sense transgenic seedlings with higher tAPX activity maintained higher chlorophyll content and showed the importance of tAPX in maintaining the optimal chloroplast development under methylviologen stress conditions, whereas the antisense lines maintained lower chlorophyll content than WT seedlings. Results indicated that the over-expression of StAPX enhanced tolerance to methylviologen-mediated oxidative stress in sense transgenic tobacco early seedlings, whereas the suppression of StAPX in antisense transgenic seedlings showed high sensitivity to oxidative stress.

Antioxidant Properties and Flavonoid Profile in Leaves of Calabrian Lavandula multifida L., an Autochthon Plant of Mediterranean Southern Regions.

PubMed

Panuccio, Maria Rosaria; Fazio, Angela; Papalia, Teresa; Barreca, Davide

2016-04-01

Lavandula multifida is a rare short-lived plant characteristic of Mediterranean basin able to survive in hot and arid climatic conditions on poorly evolved limestone soils. In this work, we characterize the enzymatic antioxidant system and phenolic composition, as well as the antioxidant properties of L. multifida fresh leaves. Enzymatic patterns show high level of peroxidases, ascorbate peroxidase, and dehydroascorbate reductase activities, when compared with L. angustifolia. The same trend is evident in total carotenoids, ascorbic acid, and reduced glutathione, and in the total antioxidant capacity assay. Moreover, RP-DAD-HPLC analyses of EtOH extract, obtained from fresh leaves, reveal main components, carvacrol, vitexin, and 7- or 8-glucoside derivatives of hypolaetin, scutellarein, luteolin, isoscutellarein, apigenin, and chrysoeriol. The analysis of this autochthon plant depicted a series of strategies adopted by L. multifida to survive in its stressful natural habitat and richness in health-promoting compounds that can be a resource for the preservation of this variety in dangerous of extinction. © 2016 Verlag Helvetica Chimica Acta AG, Zürich.

Development of a novel method for determination of mercury based on its inhibitory effect on horseradish peroxidase activity followed by monitoring the surface plasmon resonance peak of gold nanoparticles

NASA Astrophysics Data System (ADS)

Khodaveisi, Javad; Shabani, Ali Mohammad Haji; Dadfarnia, Shayessteh; Moghadam, Masoud Rohani; Hormozi-Nezhad, Mohammad Reza

2016-01-01

A highly sensitive and simple indirect spectrophotometric method has been developed for the determination of trace amounts of inorganic mercury (Hg2 +) in aqueous media. The method is based on the inhibitory effect of Hg2 + on the activity of horseradish peroxidase (HRP) in the oxidation of ascorbic acid by hydrogen peroxide followed by the reduction of Au3 + to Au-NPs by unreacted ascorbic acid and the measurement of the absorbance of localized surface plasmon resonance (LSPR) peak of gold nanoparticles (at 530 nm) which is directly proportional to the concentration of Hg2 +. Under the optimum conditions, the calibration curve was linear in the concentration range of 1-220 ng mL- 1. Limits of detection (LOD) and quantification (LOQ) were 0.2 and 0.7 ng mL- 1, respectively and the relative standard deviation at 100 ng mL- 1 level of Hg2 + was 2.6%. The method was successfully applied to the determination of mercury in different water samples.

Application of a chitosan coating as a carrier for natamycin to maintain the storage quality of ground cherry (Physalis pubescens L.)*

PubMed Central

Hao, Xiao-lei; Zhang, Jiao-jiao; Li, Xi-hong; Wang, Wei

2017-01-01

Ground cherry (Physalis pubescens L.) is a kind of berry fruit favored by consumers in China; however, this fruit is particularly vulnerable to physiological senescence and pathogen attack during the traditional cold storage period. In order to maintain storage quality, a 1.5% (w/w) chitosan (CS) water solution containing 50 mg/L of natamycin (NA) was introduced. After all treatments were completed, the fruit was stored at 0 °C and sampled every 10 d. At each sampling date, the following tests were performed: mold and yeast analyses; enzyme activity and content analyses which included superoxide dismutase (SOD), ascorbate peroxidase (APX), and malondialdehyde (MDA); and color analysis. In addition, a sensory evaluation was carried out for quality assessment at the end of the storage period. The results showed that the application of a chitosan coating combined with natamycin (CSNA) enhanced the activity of superoxide dismutase (SOD) and ascorbate peroxidase (APX), reduced the physiological rate of senescence, and inhibited pathogen attack. Thus, CSNA treatment can maintain ground cherries at an acceptable level of storage quality for 50 d.

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.

PubMed

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.

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

PubMed Central

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

Synergistic Effects of GhSOD1 and GhCAT1 Overexpression in Cotton Chloroplasts on Enhancing Tolerance to Methyl Viologen and Salt Stresses

PubMed Central

Luo, Xiaoli; Wu, Jiahe; Li, Yuanbao; Nan, Zhirun; Guo, Xing; Wang, Yixue; Zhang, Anhong; Wang, Zhian; Xia, Guixian; Tian, Yingchuan

2013-01-01

In plants, CuZn superoxide dismutase (CuZnSOD, EC l.15.1.1), ascorbate peroxidase (APX, EC 1.11.1.11), and catalase (CAT, EC l.11.1.6) are important scavengers of reactive oxygen species (ROS) to protect the cell from damage. In the present study, we isolated three homologous genes (GhSOD1, GhAPX1, and GhCAT1) from Gossypium hirsutum. Overexpressing cassettes containing chimeric GhSOD1, GhAPX1, or GhCAT1 were introduced into cotton plants by Agrobacterium transformation, and overexpressed products of these genes were transported into the chloroplasts by transit peptide, as expected. The five types of transgenic cotton plants that overexpressed GhSOD1, GhAPX1, GhCAT1, GhSOD1 and GhAPX1 stack (SAT), and GhSOD1 and GhCAT1 stack (SCT) were developed. Analyses in the greenhouse showed that the transgenic plants had higher tolerance to methyl viologen (MV) and salinity than WT plants. Interestingly, SCT plants suffered no damage under stress conditions. Based on analyses of enzyme activities, electrolyte leakage, chlorophyll content, photochemical yield (Fv/Fm), and biomass accumulation under stresses, the SCT plants that simultaneously overexpressed GhSOD1 and GhCAT1 appeared to benefit from synergistic effects of two genes and exhibited the highest tolerance to MV and salt stress among the transgenic lines, while the SAT plants simultaneously overexpressing GhSOD1 and GhAPX1 did not. In addition, transgenic plants overexpressing antioxidant enzymes in their chloroplasts had higher tolerance to salt stress than those expressing the genes in their cytoplasms, although overall enzyme activities were almost the same. Therefore, the synergistic effects of GhSOD1 and GhCAT1 in chloroplasts provide a new strategy for enhancing stress tolerance to avoid yield loss. PMID:23335985

Perturbations in carotenoid and porphyrin status result in differential photooxidative stress signaling and antioxidant responses.

PubMed

Park, Joon-Heum; Jung, Sunyo

2018-02-12

We examined differential photooxidative stress signaling and antioxidant responses in rice plants treated with norflurazon (NF) and oxyfluorfen (OF), which are inhibitors of carotenoid and porphyrin biosynthesis, respectively. Plants treated with OF markedly increased levels of cellular leakage and malondialdehyde, compared with NF-treated plants, showing that OF plants suffered greater oxidative damage with respect to membrane integrity. The enhanced production of H 2 O 2 in response to OF, but not NF, indicates the important role of H 2 O 2 in activation of photooxidative stress signaling in OF plants. In response to NF and OF, the increased levels of free salicylic acid as well as maintenance of the redox ratio of ascorbate and glutathione pools to a certain level are considered to be crucial factors in the protection against photooxidation. Plants treated with OF greatly up-regulated catalase (CAT) activity and Cat transcript levels, compared with NF-treated plants. Interestingly, NF plants showed no noticeable increase in oxidative metabolism, although they did show considerable increases in ascorbate peroxidase (APX) and peroxidase activities and transcript levels of APX, as in OF plants. Our results suggest that perturbations in carotenoid and porphyrin status by NF and OF can be sensed by differential photooxidative stress signaling, such as that involving H 2 O 2 , redox state of ascorbate and glutathione, and salicylic acid, which may be responsible for at least part of the induction of ROS-scavenging enzymes. Copyright © 2018 Elsevier Inc. All rights reserved.

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.

PubMed

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.

Inhibition of cell proliferation and migration by oxidative stress from ascorbate-driven juglone redox cycling in human bladder-derived T24 cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kviecinski, M.R., E-mail: mrkviecinski@hotmail.com; Pedrosa, R.C., E-mail: rozangelapedrosa@gmail.com; Felipe, K.B., E-mail: kakabettega@yahoo.com.br

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 inmore » 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.« less

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

PubMed

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.

Effects of a tryptophan supplemented diet and U.V. radiation on the rat lens.

PubMed

Mathur, R L; Sahai, P

1990-01-01

Rats maintained on a tryptophan supplemented diet and exposed to U.V. radiation showed decreased concentration of ascorbic acid in serum. In the lens, a small increase in the urea-mercaptoethanol soluble fraction was observed suggesting some oxidation of P-SH groups. The decreased concentrations of lens glutathione and ascorbic acid were accompanied with increased concentration of malondialdehyde suggesting increased oxidative stress. The activities of glutathione peroxidase decreased by about 40%. Though the activity of glutathione reductase decreased by about 58%, addition of FAD in the enzyme assay system showed restoration of lost activity. Additive effect of raised serum tryptophan concentration and ultraviolet radiation in causing damage to the eye lens is suggested.

Wheat stripe rust resistance protein WKS1 reduces the ability of the thylakoid-associated ascorbate peroxidase to detoxify reactive oxygen species

USDA-ARS?s Scientific Manuscript database

Stripe rust is a devastating fungal disease of wheat caused by Puccinia striiformis f. sp. tritici(Pst). The WKS1 resistance gene has an unusual combination of serine/threonine kinase and START lipid-binding domains and confers partial resistance to Pst. Here we show that wheat plants transformed w...

Enzymatic browning reactions in apple and apple products.

PubMed

Nicolas, J J; Richard-Forget, F C; Goupy, P M; Amiot, M J; Aubert, S Y

1994-01-01

This review examines the parameters of enzymatic browning in apple and apple products that is, phenolic compounds, polyphenoloxidases, and other factors (ascorbic acid and peroxidases), both qualitatively and quantitatively. Then the relationships between intensity of browning and the browning parameters are discussed, including a paragraph on the methods used for browning evaluation. Finally, the different methods for the control of browning are presented.

Changes in growth, biochemical components, and antioxidant activity in aquatic plant Wolffia arrhiza (Lemnaceae) exposed to cadmium and lead.

PubMed

Piotrowska, Alicja; Bajguz, Andrzej; Godlewska-Zyłkiewicz, Beata; Zambrzycka, Elzbieta

2010-04-01

The present study investigated the biochemical response of aquatic plant Wolffia arrhiza (Lemnaceae) treated with lead (Pb) and cadmium (Cd) at a range of concentrations from 1 to 1000 microM. W. arrhiza has been identified as good scavenger of heavy metals from aqueous solution. Pb and Cd accumulation was found to be increased in a concentration- and duration-dependent manner. However, the highest biosorption of heavy metals was found in plants exposed to low levels (10 microM) of Cd and Pb in the nutrient medium. In observing the response to heavy-metal stress, we noted inhibited plant growth and decreased photosynthetic pigments, monosaccharides, and proteins. In addition, Cd was found to be more toxic to plants than Pb. Heavy metals also induced oxidative damage as evidenced by increased lipid peroxidation and hydrogen peroxide levels. In contrast, the deleterious effects resulting from the cellular oxidative state can be alleviated by enzymatic (catalase, ascorbate peroxidase, nicotinamide dinucleotide [NADH] peroxidase) and nonenzymatic (ascorbate, glutathione) antioxidant mechanisms activated in W. arrhiza plants exposed to Cd and Pb, especially at 10 microM. These results suggest that W. arrhiza is a promising bioindicator of heavy-metal toxicity.

Chemical Compositions, Somatic Embryogenesis, and Somaclonal Variation in Cumin

PubMed Central

Tohidfar, Masoud; Sadat Noori, Seyed Ahmad; Izadi Darbandi, Ali; Rao, Rosa

2017-01-01

This is the first report evaluating the relationship between the chemical compositions of cumin seeds (based on the analysis of the content of catalase, ascorbate peroxidase, proline, protein, terpenic compounds, alcohol/phenols, aldehydes, and epoxides) and the induction efficiency of somatic embryogenesis in two Iranian superior cumin landraces (Golestan and North Khorasan). Cotyledons isolated from Golestan landrace seeds cultivated on MS medium supplemented with 0.1 mg/L kinetin proved to be the best primary explant for the induction of somatic embryogenesis as well as the regeneration of the whole plantlet. Results indicated that different developmental stages of somatic embryos were simultaneously observed on a callus with embryogenic potential. The high content of catalase, ascorbate peroxidase, proline, and terpenic hydrocarbons and low content of alcoholic and phenolic compositions had a stimulatory effect on somatic embryogenesis. Band patterns of RAPD markers in regenerated plants were different from those of the mother plants. This may be related to somaclonal variations or pollination system of cumin. Generally, measurement of chemical compositions can be used as a marker for evaluating the occurrence of somatic embryogenesis in cumin. Also, somaclonal variations of regenerated plants can be applied by the plant breeders in breeding programs. PMID:29234682

Imaging of NPQ and ROS formation in tobacco leaves: heat inactivation of the water-water cycle prevents down-regulation of PSII.

PubMed

Hideg, Eva; Kós, Péter B; Schreiber, Ulrich

2008-12-01

Non-photochemical chlorophyll fluorescence quenching (NPQ) plays a major role in the protection of the photosynthetic apparatus against damage by excess light, which is closely linked to the production of reactive oxygen species (ROS). The effect of a short heat treatment on NPQ and ROS production was studied with detached tobacco leaves by fluorescence imaging of chlorophyll and of the ROS sensor dye HO-1889NH. NPQ was stimulated >3-fold by 3 min pre-treatment at 44 degrees C, in parallel with suppression of CO(2) uptake, while no ROS formation could be detected. In contrast, after 3 min pre-treatment at 46 degrees C, NPQ was suppressed and ROS formation was indicated by quenching of HO-1889NH fluorescence. After 3 min pre-treatment at 46 degrees C and above, partial inactivation of ascorbate peroxidase and light-driven accumulation of H(2)O(2) was also observed. These data are discussed as evidence for a decisive role of the Mehler ascorbate peroxidase or water-water cycle in the formation of the NPQ that reflects down-regulation of PSII.

[Characterization of structural change of ascorbate peroxidase from Chinese kale during denaturation by circular dichroism].

PubMed

Xi, Jia-Fu; Tang, Lei; Zhang, Jian-Hua; Zhang, Hong-Jian; Chen, Xu-Sheng; Mao, Zhong-Gui

2014-11-01

Circular dichroism (CD) is a special absorption spectrum. The secondary structure of protein such as α-helix, β-sheet and β-turn in the far ultraviolet region (190-250 nm) has a characteristic CD spectrum. In order to understand the activity and structural changes of ascorbate peroxidase from Chinese kale (BaAPX) during denaturation, specific activity and percentage of secondary structure of BaAPX under different time, temperature and concentration were analyzed by CD dynamically. In addition, the percentage of four secondary structures in BaAPX was calculated by CD analysis software Dichroweb. The results show that BaAPX is a full α-type enzyme whose specific activity is positively related to the percentage of α-helix. During denaturation of BaAPX, three kinds of structural changes were proposed: the one-step structural change from initial state (N state) to minimum state of α-helix (R state) under low concentration and low temperature; the one-step structural change from N state to equilibrium state (T state) under high concentration and low temperature; the two-step structural changes from N state through R state to final T state under heat treatment and low temperature renaturation.

Development of a novel method for determination of mercury based on its inhibitory effect on horseradish peroxidase activity followed by monitoring the surface plasmon resonance peak of gold nanoparticles.

PubMed

Khodaveisi, Javad; Shabani, Ali Mohammad Haji; Dadfarnia, Shayessteh; Moghadam, Masoud Rohani; Hormozi-Nezhad, Mohammad Reza

2016-01-15

A highly sensitive and simple indirect spectrophotometric method has been developed for the determination of trace amounts of inorganic mercury (Hg(2+)) in aqueous media. The method is based on the inhibitory effect of Hg(2+) on the activity of horseradish peroxidase (HRP) in the oxidation of ascorbic acid by hydrogen peroxide followed by the reduction of Au(3+) to Au-NPs by unreacted ascorbic acid and the measurement of the absorbance of localized surface plasmon resonance (LSPR) peak of gold nanoparticles (at 530 nm) which is directly proportional to the concentration of Hg(2+). Under the optimum conditions, the calibration curve was linear in the concentration range of 1-220 ng mL(-1). Limits of detection (LOD) and quantification (LOQ) were 0.2 and 0.7 ng mL(-1), respectively and the relative standard deviation at 100 ng mL(-1) level of Hg(2+) was 2.6%. The method was successfully applied to the determination of mercury in different water samples. Copyright © 2015 Elsevier B.V. All rights reserved.

[Effect of simulative warming on growth and antioxidative characteristics of Kobresia pygmaea and K. tibetica in the permafrost region of Qinghai-Tibetan Plateau, China].

PubMed

Xiao, Yao; Wang, Gen Xu; Yang, Yan; Yang, Yang; Peng, A Hui; Zhang, Li

2017-04-18

In the present study, open top chambers (OTCs) were employed to simulate temperature increase at Fenghuoshan site, located on the hinterland of Qinghai-Tibetan Plateau. To explore the potential response mechanism of alpine plants under warmer temperature, the leaf morphological and antioxidative characteristics of two dominant species of alpine meadow (Kobresia pygmaea) and alpine swamp meadow (K. tibetica) were analyzed. The results showed that length and numbers of leaves in K. pygmaea increased by 40.0% and 72.7% by warming, respectively. Plant height and leaf length in K. tibetica increased by 11.9% and 19.3% by warming, respectively. Warming improved plant growth and aboveground biomass accumulation in both species. However, warming did not affect leaf membrane permeability (electrolyte leakage), active oxygen species (hydrogen peroxide and superoxide anion), activities of superoxide dismutase, peroxidase, ascorbate peroxidase and catalase, and malondialdehyde content in both species. Ascorbic acid and free proline contents in K. tibetica increased by 29.8% and 53.8%, respectively, but no change was found in K. pygmaea. In conclusion, K. pygmaea and K. tibetica could adapt under warmer temperature through keeping a steady antioxidative status.

Physiological responses of Kobresia pygmaea to warming in Qinghai-Tibetan Plateau permafrost region

NASA Astrophysics Data System (ADS)

Yang, Y.; Wang, G. X.; Yang, L. D.; Guo, J. Y.; Li, N.

2012-02-01

Kobresia pygmaea (C. B. Clarke) C. B. Clarke is one dominant herbaceous species in the alpine meadows of the Qinghai-Tibetan Plateau. From 2006 to 2009, a warming experiment was conducted in this permafrost region. Two 2-year warming treatments with an annual average warming of 2.1 °C and 4.4 °C, and one 4-year warming treatment with an annual average warming of 2.3 °C were established to examine physiological responses of K. pygmaea to warming. Our results indicated that 2-years of warming increased malondialdehyde and non-structural carbohydrates in the plants. There was no effect of 2-year warming on electrolyte leakage and free proline content. In the 2-year warming treatment, superoxide dismutase activity and peroxidase activity increased, ascorbate peroxidase activity and ascorbic acid only increased in 2-year high warming treatment, whereas in the 4-year warming treatment, active oxygen species, electrolyte leakage, UV-absorbing compounds and anthocyanins decreased. The 4-year warming treatment also significantly increased non-structural carbonhydrate and free proline accumulation for osmotic adjustment. The results of this study suggest that K. pygmaea could adapt to a warmer environment in the future.

Light history modulates antioxidant and photosynthetic responses of biofilms to both natural (light) and chemical (herbicides) stressors.

PubMed

Bonnineau, Chloé; Sague, Irene Gallardo; Urrea, Gemma; Guasch, Helena

2012-05-01

In multiple stress situations, the co-occurrence of environmental and chemical factors can influence organisms' ability to cope with toxicity. In this context, the influence of light adaptation on the response of freshwater biofilms to sudden light changes or to herbicides exposure was investigated by determining various parameters: diatom community composition, photosynthetic parameters, chlorophyll a content, antioxidant enzyme activities. Biofilms were grown in microcosms under sub-optimal, saturating, and high light intensities and showed already described characteristics of shade/light adaptation (community structure, photosynthetic adaptation, etc.). Light history modulated antioxidant and photosynthetic responses of biofilms to the stress caused by short-term exposure to sudden light changes or to herbicides. First biofilms adapted to sub-optimal light intensity (shade-adapted) were found to be more sensitive to an increase in light intensity than high-light adapted ones to a reduction in light intensity. Second, while light history influenced biofilms' response to glyphosate, it had little influence on biofilms' response to copper and none on its response to oxyfluorfen. Indeed glyphosate exposure led to a stronger decrease in photosynthetic efficiency of shade-adapted biofilms (EC(50) = 11.7 mg L(-1)) than of high-light adapted communities (EC(50) = 35.6 mg L(-1)). Copper exposure led to an activation of ascorbate peroxidase (APX) in biofilms adapted to sub-optimal and saturating light intensity while the protein content decreased in all biofilms exposed to copper. Oxyfluorfen toxicity was independent of light history provoking an increase in APX activity. In conclusion this study showed that both previous exposure to contaminants and physical habitat characteristics might influence community tolerance to disturbances strongly.

Effects of zinc and influence of Acremonium lolii on growth parameters, chlorophyll a fluorescence and antioxidant enzyme activities of ryegrass (Lolium perenne L. cv Apollo).

PubMed

Bonnet, M; Camares, O; Veisseire, P

2000-05-01

The effects of zinc on growth, mineral content, chlorophyll a fluorescence, and detoxifying enzyme activity (ascorbate peroxidase (APX), EC 1.11.1.11; superoxide dismutase (SOD), EC 1.15.1.1) of ryegrass infected or not by Acremonium lolii, and treated with nutrient solution containing 0-50 mM ZnSO(4) were studied. The introduction of zinc induces stress with a decrease in growth at 1, 5 and 10 mM ZnSO(4) and a cessation of growth at 50 mM ZnSO(4), in ryegrass plants infected by A. lolii or not. This decrease in growth may be due to an accumulation of zinc in leaves. Nevertheless, symbiotic plants showed higher values in tiller number, an advantage conferred by the fungus. After 24 d of Zn exposure, leaf fresh weights and leaf water content were lower in plants growing with Zn in the culture medium and no advantage was conferred by the fungus to its host. An increase in Zn supply resulted in a decrease of the Ca, K, Mg, and Cu content of the leaves, a reduction in the quantum yield of electron flow throughout photosystem II (DeltaF/F(1)(m))and a lowering of the efficiency of photosynthetic energy conversion (F(v)/F(m)), compared to control plants. To counter this zinc stress, detoxifying enzymes APX and SOD increased (100%) when Zn reached the value of 50 mM in the nutrient solution. At 10 mM ZnSO(4), the presence of the fungus in the plant led to an increase in the threshold toxicity of plants to zinc by a diminution of APX activity.

A study on the activities of a few free radicals scavenging enzymes present in five roadside plants.

PubMed

Mandal, M; Mukherji, S

2001-10-01

The road side plants are continuously exposed to the high levels of oxides of nitrogen and sulphur dioxide, emitted from automobile. Resistance to automobile exhaust pollution was studied with Nerium indicum Mill, Boerhaavia diffusa L., Amaranthus spinosus L., Cephalandra indica Naud., and Tabernaemontana divaricata L., growing on the edges of Delhi Road, National Highway 2 (NH 2) near Dankuni, West Bengal. By analysing the activities of a few enzymes like superoxide dismutase, catalase, ascorbate peroxidase, glutathione reductase and phenolic peroxidase, it appears that among the five plants examined,Amaranthus and Cephalandra are equipped with a very good scavenging system to combat effects of air pollution.

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

NASA Astrophysics Data System (ADS)

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.

Future Climate CO2 Levels Mitigate Stress Impact on Plants: Increased Defense or Decreased Challenge?

PubMed Central

AbdElgawad, Hamada; Zinta, Gaurav; Beemster, Gerrit T. S.; Janssens, Ivan A.; Asard, Han

2016-01-01

Elevated atmospheric CO2 can stimulate plant growth by providing additional C (fertilization effect), and is observed to mitigate abiotic stress impact. Although, the mechanisms underlying the stress mitigating effect are not yet clear, increased antioxidant defenses, have been held primarily responsible (antioxidant hypothesis). A systematic literature analysis, including “all” papers [Web of Science (WoS)-cited], addressing elevated CO2 effects on abiotic stress responses and antioxidants (105 papers), confirms the frequent occurrence of the stress mitigation effect. However, it also demonstrates that, in stress conditions, elevated CO2 is reported to increase antioxidants, only in about 22% of the observations (e.g., for polyphenols, peroxidases, superoxide dismutase, monodehydroascorbate reductase). In most observations, under stress and elevated CO2 the levels of key antioxidants and antioxidant enzymes are reported to remain unchanged (50%, e.g., ascorbate peroxidase, catalase, ascorbate), or even decreased (28%, e.g., glutathione peroxidase). Moreover, increases in antioxidants are not specific for a species group, growth facility, or stress type. It seems therefore unlikely that increased antioxidant defense is the major mechanism underlying CO2-mediated stress impact mitigation. Alternative processes, probably decreasing the oxidative challenge by reducing ROS production (e.g., photorespiration), are therefore likely to play important roles in elevated CO2 (relaxation hypothesis). Such parameters are however rarely investigated in connection with abiotic stress relief. Understanding the effect of elevated CO2 on plant growth and stress responses is imperative to understand the impact of climate changes on plant productivity. PMID:27200030

Synthesis, characterization and antioxidant study of N,N’-bis(2-chlorobenzamidothiocarbonyl)hydrazine

DOE Office of Scientific and Technical Information (OSTI.GOV)

Firdausiah, Syadza; Hasbullah, Siti Aishah; Yamin, Bohari M.

2015-09-25

N,N’-bis(2-chlorobenzamidothiocarbonyl)hydrazine was synthesized from 2-chlorobenzoylisothiocyanate and hydrazine in acetone. The compound was characterized by infrared, {sup 1}H and {sup 13}C NMR, and UV-Vis spectroscopies. X-ray crystallography study showed the molecule adopt trans configuration at both N-N and C-N bonds. The compound showed high antioxidant activity, EC{sub 50} of 374.89 µM, compared to ascorbic acid (EC{sub 50} of 561.36 µM)

Transformation of plum plants with a cytosolic ascorbate peroxidase transgene leads to enhanced water stress tolerance

PubMed Central

Diaz-Vivancos, Pedro; Faize, Lydia; Nicolás, Emilio; Clemente-Moreno, Maria José; Bru-Martinez, Roque; Burgos, Lorenzo; Hernández, José Antonio

2016-01-01

Background and Aims Water deficit is the most serious environmental factor limiting agricultural production. In this work, the tolerance to water stress (WS) of transgenic plum lines harbouring transgenes encoding cytosolic antioxidant enzymes was studied, with the aim of achieving the durable resistance of commercial plum trees. Methods The acclimatization process was successful for two transgenic lines: line C3-1, co-expressing superoxide dismutase (two copies) and ascorbate peroxidase (one copy) transgenes simultaneously; and line J8-1, harbouring four copies of the cytosolic ascorbate peroxidase gene (cytapx). Plant water relations, chlorophyll fluorescence and the levels of antioxidant enzymes were analysed in both lines submitted to moderate (7 d) and severe (15 d) WS conditions. Additionally, in line J8-1, showing the best response in terms of stress tolerance, a proteomic analysis and determination of the relative gene expression of two stress-responsive genes were carried out. Key Results Line J8-1 exhibited an enhanced stress tolerance that correlated with better photosynthetic performance and a tighter control of water-use efficiency. Furthermore, this WS tolerance also correlated with a higher enzymatic antioxidant capacity than wild-type (WT) and line C3-1 plum plants. On the other hand, line C3-1 displayed an intermediate phenotype between WT plants and line J8-1 in terms of WS tolerance. Under severe WS, the tolerance displayed by J8-1 plants could be due to an enhanced capacity to cope with drought-induced oxidative stress. Moreover, proteomic analysis revealed differences between WT and J8-1 plants, mainly in terms of the abundance of proteins related to carbohydrate metabolism, photosynthesis, antioxidant defences and protein fate. Conclusions The transformation of plum plants with cytapx has a profound effect at the physiological, biochemical, proteomic and genetic levels, enhancing WS tolerance. Although further experiments under field conditions will be required, it is proposed that J8-1 plants would be an interesting Prunus rootstock for coping with climate change. PMID:27059431

Transformation of plum plants with a cytosolic ascorbate peroxidase transgene leads to enhanced water stress tolerance.

PubMed

Diaz-Vivancos, Pedro; Faize, Lydia; Nicolás, Emilio; Clemente-Moreno, Maria José; Bru-Martinez, Roque; Burgos, Lorenzo; Hernández, José Antonio

2016-06-01

Water deficit is the most serious environmental factor limiting agricultural production. In this work, the tolerance to water stress (WS) of transgenic plum lines harbouring transgenes encoding cytosolic antioxidant enzymes was studied, with the aim of achieving the durable resistance of commercial plum trees. The acclimatization process was successful for two transgenic lines: line C3-1, co-expressing superoxide dismutase (two copies) and ascorbate peroxidase (one copy) transgenes simultaneously; and line J8-1, harbouring four copies of the cytosolic ascorbate peroxidase gene (cytapx). Plant water relations, chlorophyll fluorescence and the levels of antioxidant enzymes were analysed in both lines submitted to moderate (7 d) and severe (15 d) WS conditions. Additionally, in line J8-1, showing the best response in terms of stress tolerance, a proteomic analysis and determination of the relative gene expression of two stress-responsive genes were carried out. Line J8-1 exhibited an enhanced stress tolerance that correlated with better photosynthetic performance and a tighter control of water-use efficiency. Furthermore, this WS tolerance also correlated with a higher enzymatic antioxidant capacity than wild-type (WT) and line C3-1 plum plants. On the other hand, line C3-1 displayed an intermediate phenotype between WT plants and line J8-1 in terms of WS tolerance. Under severe WS, the tolerance displayed by J8-1 plants could be due to an enhanced capacity to cope with drought-induced oxidative stress. Moreover, proteomic analysis revealed differences between WT and J8-1 plants, mainly in terms of the abundance of proteins related to carbohydrate metabolism, photosynthesis, antioxidant defences and protein fate. The transformation of plum plants with cytapx has a profound effect at the physiological, biochemical, proteomic and genetic levels, enhancing WS tolerance. Although further experiments under field conditions will be required, it is proposed that J8-1 plants would be an interesting Prunus rootstock for coping with climate change. © The Author 2016. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

High dosage of ascorbic acid and alpha-tocopherol is not useful for diminishing oxidative stress and DNA damage in healthy elderly adults.

PubMed

Retana-Ugalde, Raquel; Casanueva, Esther; Altamirano-Lozano, Mario; González-Torres, Cristina; Mendoza-Núñez, Víctor Manuel

2008-01-01

To determine the useful dosage of ascorbic acid and alpha-tocopherol against oxidative stress and DNA damage in the elderly. A double-blind controlled clinical assay carried out in a sample of 66 healthy subjects divided into three age-paired random groups with 22 subjects in each group. Group A received placebo and group B was administered 500 mg of ascorbic acid and 400 IU of alpha-tocopherol, whereas group C received 1,000 mg of ascorbic acid and 400 IU of alpha-tocopherol for a 6-month period. The following measurements were performed before and after the 6-month treatment period: thiobarbituric acid reactive substances (TBARS); total antioxidant status (TAS); superoxide dismutase (SOD), and glutation peroxidase (GPx) and DNA damage by comet assay. After 6 months, group B subjects exhibited an increase in SOD and GPx enzyme levels; however, this was not statistically significant (p > 0.05). Likewise, TBARS and TAS concentrations remained unchanged (p > 0.05). In addition, in group C the decrease in TBARS and increase in SOD, GPx, and TAS were not statistically significant (p > 0.05). Similarly, average DNA migration showed no significant differences with high-dosage ascorbic acid and alpha-tocopherol. These findings suggest that administration of 1,000 mg of ascorbic acid plus 400 IU of alpha-tocopherol for 6 months is not useful for diminishing oxidative stress and DNA damage in healthy elderly adults. 2008 S. Karger AG, Basel.

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

PubMed

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.

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

PubMed

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.

Supplementation of ascorbic acid and alpha-tocopherol is useful to preventing bone loss linked to oxidative stress in elderly.

PubMed

Ruiz-Ramos, M; Vargas, L Alberto; Fortoul Van der Goes, T I; Cervantes-Sandoval, A; Mendoza-Nunez, V M

2010-06-01

To determine the effect of ascorbic acid and alpha-tocopherol on oxidative stress and bone mineral density (BMD) in elderly people. A double-blind, controlled clinical assay was carried out in a sample of 90 elderly subjects divided into three age-paired random groups with 30 subjects in each group. Group Tx0 received placebo, group Tx1 received 500 mg of ascorbic acid and 400 IU of alpha-tocopherol, whereas group Tx2 received 1,000 mg of ascorbic acid and 400 IU of alpha-tocopherol, for a 12-month period. We measured thiobarbituric acid reactive substances (TBARS), total antioxidant status (TAS), superoxide dismutase (SOD), and glutation peroxidase (GPx); BMD was obtained on DXA of hip and spine before and after the 12-month treatment period with supplementation of vitamins C and E. We found a positive correlation between hip-BMD and SOD (r = 0.298, p < 0.05) and GPx (r = 0.214, p < 0.05). Also, a significantly lower decrease of LPO (p < 0.05) was observed as linked with hip bone loss in the Tx2 group than in the Tx0 group. Our findings suggest that that administration of 1,000 mg of ascorbic acid together with 400 IU of alpha-tocopherol could be useful in preventing or aiding in the treatment of age-related osteoporosis.

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

PubMed Central

Sytykiewicz, Hubert

2016-01-01

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. PMID:26907270

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

PubMed

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.

Toxic effects of copper-based nanoparticles or compounds to lettuce (Lactuca sativa) and alfalfa (Medicago sativa).

PubMed

Hong, Jie; Rico, Cyren M; Zhao, Lijuan; Adeleye, Adeyemi S; Keller, Arturo A; Peralta-Videa, Jose R; Gardea-Torresdey, Jorge L

2015-01-01

The increased production and use of nanoparticles (NPs) has generated concerns about their impact on living organisms. In this study, nCu, bulk Cu, nCuO, bulk CuO, Cu(OH)2 (CuPRO 2005, Kocide 3000), and CuCl2 were exposed for 15 days to 10 days-old hydroponically grown lettuce (Lactuca sativa) and alfalfa (Medicago sativa). Each compound was applied at 0, 5, 10, and 20 mg L(-1). At harvest, we measured the size of the plants and determined the concentration of Cu, macro and microelements by using ICP-OES. Catalase and ascorbate peroxidase activity was also determined. Results showed that all Cu NPs/compounds reduced the root length by 49% in both plant species. All Cu NPs/compounds increased Cu, P, and S (>100%, >50%, and >20%, respectively) in alfalfa shoots and decreased P and Fe in lettuce shoot (>50% and >50%, respectively, excluding Fe in CuCl2 treatment). Biochemical assays showed reduced catalase activity in alfalfa (root and shoot) and increased ascorbate peroxidase activity in roots of both plant species. Results suggest that Cu NPs/compounds not only reduced the size of the plants but altered nutrient content and enzyme activity in both plant species.

Effects of 1-methylcyclopropene and post-controlled atmosphere air storage treatments on fresh-cut Ambrosia apple slices.

PubMed

Tardelli, Francesca; Guidi, Lucia; Massai, Rossano; Toivonen, Peter M A

2013-01-01

The effect of 1-methylcyclopropene (1-MCP) treatment and two different post-controlled atmosphere air storage (PCAAS) durations on the quality and chemistry of fresh-cut Ambrosia apple slices was studied. PCAAS for 1 or 2 weeks prior to slicing had an overall positive effect on the resultant quality of fresh-cut apple slices. The most significant responses to PCAAS were the suppression of both phenolic and o-quinone accumulation in slices, and this was related to the significantly lower browning potential values obtained for slices from PCAAS-treated apples. Polyphenol oxidase (PPO), peroxidase (POX) and ascorbate peroxidase (APOX) activities were not affected by 1-MCP or PCAAS treatments. PPO and POX activities were almost completely inhibited by a 50 g L⁻¹ calcium ascorbate anti-browning dip of apple slices from all treatments. The most dramatic effect of the PCAAS treatments was to reduce the accumulation of soluble phenolics, which is likely the reason that o-quinone accumulation was also inhibited in treated fruits. The consequent reduction in browning potential may be the explanation as to why PCAAS treatment has been shown to reduce fresh apple slice browning in previous work. Copyright © 2012 Society of Chemical Industry.

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

PubMed

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

PubMed Central

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. PMID:22645501

The membrane-tethered transcription factor ANAC089 serves as redox-dependent suppressor of stromal ascorbate peroxidase gene expression

PubMed Central

Klein, Peter; Seidel, Thorsten; Stöcker, Benedikt; Dietz, Karl-Josef

2012-01-01

The stromal ascorbate peroxidase (sAPX) functions as central element of the chloroplast antioxidant defense system. Its expression is under retrograde control of chloroplast signals including redox- and reactive oxygen species-linked cues. The sAPX promoter of Arabidopsis thaliana was dissected in transient reporter assays using mesophyll protoplasts. The study revealed regulatory elements up to –1868 upstream of the start codon. By yeast-one-hybrid screening, the transcription factor ANAC089 was identified to bind to the promoter fragment 2 (–1262 to –1646 bp upstream of translational initiation). Upon mutation of the cis-acting element CACG, binding of ANAC089 was abolished. Expression of a fused fluorescent protein version and comparison with known endomembrane markers localized ANAC089 to the trans-Golgi network and the ER. The transcription factor was released upon treatment with reducing agents and targeted to the nucleus. Transactivation assays using wild type and mutated versions of the promoter showed a partial suppression of reporter expression. The data indicate that ANAC089 functions in a negative retrograde loop, lowering sAPX expression if the cell encounters a highly reducing condition. This conclusion was supported by reciprocal transcript accumulation of ANAC089 and sAPX during acclimation to low, normal, and high light conditions. PMID:23162559

Increased expression of native cytosolic Cu/Zn superoxide dismutase and ascorbate peroxidase improves tolerance to oxidative and chilling stresses in cassava (Manihot esculenta Crantz)

PubMed Central

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 dismutase (SOD), MeCu/ZnSOD, and ascorbate peroxidase (APX), MeAPX2, were produced and tested for tolerance against oxidative and chilling stresses. The up-regulation of MeCu/ZnSOD and MeAPX2 expression was confirmed by the quantitative reverse transcriptase-polymerase chain reaction, and enzymatic activity analyses in the leaves of transgenic cassava plant lines with a single-transgene integration site. Upon exposure to ROS-generating agents, 100 μM ROS-generating reagent methyl viologen and 0.5 M H2O2, higher levels of enzymatic activities of SOD and APX were detected in transgenic plants than the wild type. Consequently, the oxidative stress parameters, such as lipid peroxidation, chlorophyll degradation and H2O2 synthesis, were lower in the transgenic lines than the wild type. Tolerance to chilling stress at 4°C for 2 d was greater in transgenic cassava, as observed by the higher levels of SOD, catalase, and ascorbate-glutathione cycle enzymes (e.g., APX, monodehydroascorbate reductase, dehydroascorbate reducatase and glutathione reductase) and lower levels of malondialdehyde content. Conclusions These results suggest that the expression of native cytosolic SOD and APX simultaneously activated the antioxidative defense mechanisms via cyclic ROS scavenging, thereby improving its tolerance to cold stress. PMID:25091029

Increased expression of native cytosolic Cu/Zn superoxide dismutase and ascorbate peroxidase improves tolerance to oxidative and chilling stresses in cassava (Manihot esculenta Crantz).

PubMed

Xu, Jia; Yang, Jun; Duan, Xiaoguang; Jiang, Yueming; Zhang, Peng

2014-08-05

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. Transgenic cassava plants that co-express cytosolic superoxide dismutase (SOD), MeCu/ZnSOD, and ascorbate peroxidase (APX), MeAPX2, were produced and tested for tolerance against oxidative and chilling stresses. The up-regulation of MeCu/ZnSOD and MeAPX2 expression was confirmed by the quantitative reverse transcriptase-polymerase chain reaction, and enzymatic activity analyses in the leaves of transgenic cassava plant lines with a single-transgene integration site. Upon exposure to ROS-generating agents, 100 μM ROS-generating reagent methyl viologen and 0.5 M H₂O₂, higher levels of enzymatic activities of SOD and APX were detected in transgenic plants than the wild type. Consequently, the oxidative stress parameters, such as lipid peroxidation, chlorophyll degradation and H₂O₂ synthesis, were lower in the transgenic lines than the wild type. Tolerance to chilling stress at 4°C for 2 d was greater in transgenic cassava, as observed by the higher levels of SOD, catalase, and ascorbate-glutathione cycle enzymes (e.g., APX, monodehydroascorbate reductase, dehydroascorbate reducatase and glutathione reductase) and lower levels of malondialdehyde content. These results suggest that the expression of native cytosolic SOD and APX simultaneously activated the antioxidative defense mechanisms via cyclic ROS scavenging, thereby improving its tolerance to cold stress.

Antioxidant defense gene analysis in Brassica oleracea and Trifolium repens exposed to Cd and/or Pb.

PubMed

Bernard, F; Dumez, S; Brulle, F; Lemière, S; Platel, A; Nesslany, F; Cuny, D; Deram, A; Vandenbulcke, F

2016-02-01

This study focused on the expression analysis of antioxidant defense genes in Brassica oleracea and in Trifolium repens. Plants were exposed for 3, 10, and 56 days in microcosms to a field-collected suburban soil spiked by low concentrations of cadmium and/or lead. In both species, metal accumulations and expression levels of genes encoding proteins involved and/or related to antioxidant defense systems (glutathione transferases, peroxidases, catalases, metallothioneins) were quantified in leaves in order to better understand the detoxification processes involved following exposure to metals. It appeared that strongest gene expression variations in T. repens were observed when plants are exposed to Cd (metallothionein and ascorbate peroxidase upregulations) whereas strongest variations in B. oleracea were observed in case of Cd/Pb co-exposures (metallothionein, glutathione transferase, and peroxidase upregulations). Results also suggest that there is a benefit to use complementary species in order to better apprehend the biological effects in ecotoxicology.

Spermidine-mediated hydrogen peroxide signaling enhances the antioxidant capacity of salt-stressed cucumber roots.

PubMed

Wu, Jianqiang; Shu, Sheng; Li, Chengcheng; Sun, Jin; Guo, Shirong

2018-07-01

Hydrogen peroxide (H 2 O 2 ) is a key signaling molecule that mediates a variety of physiological processes and defense responses against abiotic stress in higher plants. In this study, our aims are to clarify the role of H 2 O 2 accumulation induced by the exogenous application of spermidine (Spd) to cucumber (Cucumis sativus) seedlings in regulating the antioxidant capacity of roots under salt stress. The results showed that Spd caused a significant increase in endogenous polyamines and H 2 O 2 levels, and peaked at 2 h after salt stress. Spd-induced H 2 O 2 accumulation was blocked under salt stress by pretreatment with a H 2 O 2 scavenger and respective inhibitors of cell wall peroxidase (CWPOD; EC: 1.11.1.7), polyamine oxidase (PAO; EC: 1.5.3.11) and NADPH oxidase (NOX; EC: 1.6.3.1); among these three inhibitors, the largest decrease was found in response to the addition of the inhibitor of polyamine oxidase. In addition, we observed that exogenous Spd could increase the activities of the enzymes superoxide dismutase (SOD; EC: 1.15.1.1), peroxidase (POD; EC: 1.11.1.7) and catalase (CAT; EC: 1.11.1.6) as well as the expression of their genes in salt-stressed roots, and the effects were inhibited by H 2 O 2 scavengers and polyamine oxidase inhibitors. These results suggested that, by regulating endogenous PAs-mediated H 2 O 2 signaling in roots, Spd could enhance antioxidant enzyme activities and reduce oxidative damage; the main source of H 2 O 2 was polyamine oxidation, which was associated with improved tolerance and root growth recovery of cucumber under salt stress. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

Evaluation of in vitro enzymatic and non-enzymatic antioxidant properites of leaf extract from Alpinia Purpurata (Vieill.) K. Schum.

PubMed

Raj, Chinthamony Arul; Ragavendran, Paramasivam; Sophia, Dominic; Starlin, Thangarajan; Rathi, Muthian Ahalliya; Gopalakrishnan, Velliyur Kanniappan

2016-09-01

To evaluate the enzymatic and non-enzymatic antioxidants of leaf extract from Alpinia purpurata. One gram of fresh leaf of Alpinia purpurata was grinded in 2 mL of 50% ethanol and centrifuged at 10,000×g at 4°C for 10 min. The supernatant obtained was used within 4 h for various enzymatic antioxidants assays like superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione S-transferase (GST), ascorbate oxidase, peroxidase, polyphenol oxidase (PPO) and non-enzymatic antioxidants such as vitamin C, total reduced glutathione (TRG) and lipid peroxidation (LPO). The leaf extract of Alpinia purpurata possess antioxidants like vitamin C 472.92±6.80 μg/mg protein, GST 372.11±5.70 μmol of 1-chloro 2,4 dinitrobenzene (CDNB)-reduced glutathione (GSH) conjugate formed/min/mg protein, GPx 281.69±6.43 μg of glutathione oxidized/min/mg protein, peroxidases 173.12±9.40 μmol/g tissue, TRG 75.27±3.55 μg/mg protein, SOD 58.03±2.11 U/mg protein, CAT 46.70±2.35 μmol of H2O2 consumed/min/mg protein in high amount whereas ascorbate oxidase 17.41±2.46 U/g tissue, LPO 2.71±0.14 nmol/L of malondialdehyde formed/min/mg protein and PPO 1.14±0.11 μmol/g tissue in moderate amount. Alpinia purpurata has the potential to scavenge the free radicals and protect against oxidative stress causing diseases. In future, Alpinia purpurata may serve as a good pharmacotherapeutic agent.

2-cysteine peroxiredoxins and thylakoid ascorbate peroxidase create a water-water cycle that is essential to protect the photosynthetic apparatus under high light stress conditions.

PubMed

Awad, Jasmin; Stotz, Henrik U; Fekete, Agnes; Krischke, Markus; Engert, Cornelia; Havaux, Michel; Berger, Susanne; Mueller, Martin J

2015-04-01

Different peroxidases, including 2-cysteine (2-Cys) peroxiredoxins (PRXs) and thylakoid ascorbate peroxidase (tAPX), have been proposed to be involved in the water-water cycle (WWC) and hydrogen peroxide (H2O2)-mediated signaling in plastids. We generated an Arabidopsis (Arabidopsis thaliana) double-mutant line deficient in the two plastid 2-Cys PRXs (2-Cys PRX A and B, 2cpa 2cpb) and a triple mutant deficient in 2-Cys PRXs and tAPX (2cpa 2cpb tapx). In contrast to wild-type and tapx single-knockout plants, 2cpa 2cpb double-knockout plants showed an impairment of photosynthetic efficiency and became photobleached under high light (HL) growth conditions. In addition, double-mutant plants also generated elevated levels of superoxide anion radicals, H2O2, and carbonylated proteins but lacked anthocyanin accumulation under HL stress conditions. Under HL conditions, 2-Cys PRXs seem to be essential in maintaining the WWC, whereas tAPX is dispensable. By comparison, this HL-sensitive phenotype was more severe in 2cpa 2cpb tapx triple-mutant plants, indicating that tAPX partially compensates for the loss of functional 2-Cys PRXs by mutation or inactivation by overoxidation. In response to HL, H2O2- and photooxidative stress-responsive marker genes were found to be dramatically up-regulated in 2cpa 2cpb tapx but not 2cpa 2cpb mutant plants, suggesting that HL-induced plastid to nucleus retrograde photooxidative stress signaling takes place after loss or inactivation of the WWC enzymes 2-Cys PRX A, 2-Cys PRX B, and tAPX. © 2015 American Society of Plant Biologists. All Rights Reserved.

Cadmium-Induced Changes in Antioxidative Systems, Hydrogen Peroxide Content, and Differentiation in Scots Pine Roots1

PubMed Central

Schützendübel, Andres; Schwanz, Peter; Teichmann, Thomas; Gross, Kristina; Langenfeld-Heyser, Rosemarie; Godbold, Douglas L.; Polle, Andrea

2001-01-01

To investigate whether Cd induces common plant defense pathways or unspecific necrosis, the temporal sequence of physiological reactions, including hydrogen peroxide (H2O2) production, changes in ascorbate-glutathione-related antioxidant systems, secondary metabolism (peroxidases, phenolics, and lignification), and developmental changes, was characterized in roots of hydroponically grown Scots pine (Pinus sylvestris) seedlings. Cd (50 μm, 6 h) initially increased superoxide dismutase, inhibited the systems involved in H2O2 removal (glutathione/glutathione reductase, catalase [CAT], and ascorbate peroxidase [APX]), and caused H2O2 accumulation. Elongation of the roots was completely inhibited within 12 h. After 24 h, glutathione reductase activities recovered to control levels; APX and CAT were stimulated by factors of 5.5 and 1.5. Cell death was increased. After 48 h, nonspecific peroxidases and lignification were increased, and APX and CAT activities were decreased. Histochemical analysis showed that soluble phenolics accumulated in the cytosol of Cd-treated roots but lignification was confined to newly formed protoxylem elements, which were found in the region of the root tip that normally constitutes the elongation zone. Roots exposed to 5 μm Cd showed less pronounced responses and only a small decrease in the elongation rate. These results suggest that in cells challenged by Cd at concentrations exceeding the detoxification capacity, H2O2 accumulated because of an imbalance of redox systems. This, in turn, may have triggered the developmental program leading to xylogenesis. In conclusion, Cd did not cause necrotic injury in root tips but appeared to expedite differentiation, thus leading to accelerated aging. PMID:11706171

Formulation with ascorbic acid and sucrose modulates catechin bioavailability from green tea

PubMed Central

Peters, Catrina M.; Green, Rodney J.; Janle, Elsa M.; Ferruzzi, Mario G.

2009-01-01

In order to investigate the impact of common food ingredients on catechin absorption, green tea (GT) extract (50 mg) was formulated plain, with sucrose (GT+S), with ascorbic acid (GT+AA) and with sucrose and ascorbic acid (GT+S+AA). Bioavailability and bioaccessibility were assessed in Sprague Dawley rats and an in vitro digestion/Caco-2 cell model respectively. Absorption of epigallocatechin (EGC) and epigallocatechin gallate (EGCG) was significantly (P<0.05) enhanced in GT+S+AA formulations (AUC0-6h= 3237.0 and 181.8 pmol*h/L plasma respectively) relative to GT control (AUC0-6h = 1304.1 and 61.0 pmol*h/L plasma respectively). In vitro digestive recovery was higher for EGC and epicatechin (EC) (∼51-53%) relative to EGCG and epicatechin gallate (ECG) (< 20%) and was modestly enhanced in GT+S and GT+S+AA formulations. Accumulation of EGC, EGCG and ECG by Caco-2 cells was significantly (P<0.05) higher from GT+S+AA compared to other formulations while retention of catechins was enhanced in presence of ascorbic acid. These data suggest that formulation with sucrose and ascorbic acid may improve catechin bioavailability by enhancing bioaccessibility and intestinal uptake from tea. PMID:20161530

Phenylethylamine-induced generation of reactive oxygen species and ascorbate free radicals in tobacco suspension culture: mechanism for oxidative burst mediating Ca2+ influx.

PubMed

Kawano, T; Pinontoan, R; Uozumi, N; Morimitsu, Y; Miyake, C; Asada, K; Muto, S

2000-11-01

In the previous paper [Kawano et al. (2000a) Plant Cell Physiol. 41: 1251], we demonstrated that addition of phenylethylamine (PEA) and benzylamine can induce an immediate and transient burst of active oxygen species (AOS) in tobacco suspension culture. Detected AOS include H2O2, superoxide anion and hydroxyl radicals. Use of several inhibitors suggested the presence of monoamine oxidase-like H2O2-generating activity in the cellular soluble fraction. It was also suggested that peroxidase(s) or copper amine oxidase(s) are involved in the extracellular superoxide production as a consequence of H2O2 production. Since more than 85% of the PEA-dependent AOS generating activity was localized in the extracellular space (extracellular fluid + cell wall), extracellularly secreted enzymes, probably peroxidases, may largely contribute to the oxidative burst induced by PEA. The PEA-induced AOS generation was also observed in the horseradish peroxidase (HRP) reaction mixture, supporting the hypothesis that peroxidases catalyze the oxidation of PEA leading to AOS generation. In addition to AOS production, we observed that PEA induced an increase in monodehydroascorbate radicals (MDA) in the cell suspension culture and in HRP reaction mixture using electron spin resonance spectroscopy and the newly invented MDA reductase-coupled method. Here we report that MDA production is an indicator of peroxidase-mediated generation of PEA radical species in tobacco suspension culture.

Investigation of hydrazide derivatives inhibitory effect on peroxidase enzyme purified from turnip roots

NASA Astrophysics Data System (ADS)

Almaz, Züleyha; Öztekin, Aykut; Özdemir, Hasan

2017-04-01

Peroxidases (EC: 1.11.1.7) are haem proteins and contain iron (III) protoporphyrin IX (ferriprotoporphyrin IX) as the prosthetic group [1]. They are found in all cells and play a critical role in many biological processes, such as the host-defense mechanism [2]. Peroxidases (PODs) are widely used in clinical biochemistry, enzyme immunoassays, synthesis of various aromatic chemicals, treatment of waste water containing phenolic compounds [3, 4]. In this study, peroxidase enzyme was purified with Para amino benzohydrazide (PABH)-L-Tyrosine Sepharose 4B affinity chromatography to investigate the inhibitory effect of hydrazide derivatives on Turnip (Brassica rapa L.). IC50 values and Ki constants were calculated for the molecules of 6-Amino nicotinic hydrazide, 6-Amino-5-bromo nicotinic hydrazide, 2-Amino-5-hydroxy benzohydrazide, 4-Amino-3-hydroxy benzohydrazide on purified enzyme and inhibition type of these molecules were determined.

Antioxidant Defenses against Activated Oxygen in Pea Nodules Subjected to Water Stress.

PubMed Central

Gogorcena, Y.; Iturbe-Ormaetxe, I.; Escuredo, P. R.; Becana, M.

1995-01-01

The involvement of activated oxygen in the drought-induced damage of pea (Pisum sativum L. cv Frilene) nodules was examined. To this purpose, various pro-oxidant factors, antioxidant enzymes and related metabolites, and markers of oxidative damage were determined in nodules of well-watered (nodule water potential approximately -0.29 MPa) and water-stressed (nodule water potential approximately -2.03 MPa) plants. Water-stressed nodules entered senescence as evidenced by the 30% decrease in leghemoglobin and total soluble protein. Drought also caused a decrease in the activities of catalase (25%), ascorbate peroxidase (18%), dehydroascorbate reductase (15%), glutathione reductase (31%), and superoxide dismutase (30%), and in the contents of ascorbate (59%), reduced (57%) and oxidized (38%) glutathione, NAD+ and NADH (43%), NADP+ (31%), and NADPH (17%). The decline in the antioxidant capacity of nodules may result from a restricted supply of NAD(P)H in vivo for the ascorbate-glutathione pathway and from the Fe-catalyzed Fenton reactions of ascorbate and glutathione with activated oxygen. The 2-fold increase in the content of "catalytic Fe" would also explain the augmented levels of lipid peroxides (2.4-fold) and oxidatively modified proteins (1.4-fold) found in water-stressed nodules because of the known requirement of lipid and protein oxidation for a transition catalytic metal. PMID:12228507

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

NASA Astrophysics Data System (ADS)

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

NASA Astrophysics Data System (ADS)

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 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. Electronic supplementary information (ESI) available. See DOI: 10.1039/c4nr07056a

Ascorbic acid enhances oxidative stress tolerance and biological control efficacy of Pichia caribbica against postharvest blue mold decay of apples.

PubMed

Li, Chaolan; Zhang, Hongyin; Yang, Qiya; Komla, Mahunu Gustav; Zhang, Xiaoyun; Zhu, Shuyun

2014-07-30

The effect of ascorbic acid (VC) on improving oxidative stress tolerance of Pichia caribbica and biocontrol efficacy against blue mold caused by Penicillium expansum on apples was investigated. P. caribbica showed susceptibility to the oxidative stress in vitro test, and 250 μg/mL VC treatment improved its oxidative stress tolerance. The higher viability exhibited by VC-treated yeast was associated with a lower intracellular ROS level. The activities of antioxidant enzymes of P. caribbica were improved by VC treatment, including catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GPX). Additionally, VC-treated yeast exhibited greater biocontrol activity against P. expansum and faster growth when stored at 25 and 4 °C, respectively, compared to the performance of the non-VC-treated yeast. In response to the VC treatment under oxidative stress, several differentially expressed proteins were identified in P. caribbica, and most of the poteins were confirmed to be related to basic metabolism. Therefore, the application of ascorbic acid is a useful approach to improve oxidative stress tolerance of P. caribbica and its biocontrol efficacy on apples.

Oxidative coupling of a feruloyl-arabinoxylan trisaccharide (FAXX) in the walls of living maize cells requires endogenous hydrogen peroxide and is controlled by a low-Mr apoplastic inhibitor.

PubMed

Encina, Antonio; Fry, Stephen C

2005-12-01

Feruloyl-polysaccharides can be oxidatively coupled in isolated cell walls by peroxidase plus exogenous H(2)O(2) in vitro, but the extent to which similar reactions may occur in the apoplast in vivo was unclear. Numerous cellular factors potentially control feruloyl coupling in vivo, and their net controlling influence is not readily studied in vitro. Therefore, we have monitored apoplastic feruloyl coupling in cultured maize cells in vivo using a radiolabelled model substrate, 5-O-feruloyl-alpha-L: -arabinofuranosyl-(1-->3)-beta-D: -xylopyranosyl-(1-->4)-D: -xylose (FAXX). FAXX was expected to permeate the wall and to undergo reactions analogous to those normally exhibited by apoplastic feruloyl-polysaccharides in vivo. Little difference was found between the fates of [feruloyl-(14)C]FAXX and [pentosyl-(3)H]FAXX, indicating negligible apoplastic hydrolase or transferase activities. Very little radioactivity entered the protoplasm. Maize cells that had recently been washed in fresh medium were able to bind most of the FAXX (90%) in their cell walls, regardless of the age of the culture. During wall-binding, the [(14)C]feruloyl groups were converted to [(14)C]dehydrodiferulates and larger coupling products, as revealed by TLC after alkaline hydrolysis. As expected for an oxidative reaction, wall-binding was delayed by added anti-oxidants (ascorbate, ferulate, sinapate, chlorogenate or rutin). It was also completely inhibited by iodide, an H(2)O(2)-scavenger, indicating a role for peroxidase rather than oxidase. The observations indicate that oxidative coupling of feruloyl groups occurred within the cell wall, dependent on endogenous apoplastic H(2)O(2) and wall-localised peroxidase, in vivo. Cells that had not recently been washed in fresh medium were much less able to bind FAXX, indicating the presence in the apoplast of an endogenous inhibitor of oxidative coupling. This inhibitor was of low M(r), was destroyed by heating, and remained in the aqueous phase (pH approximately 3.5) when shaken with ethyl acetate. Its effectiveness was not altered by ascorbate oxidase. It is thus a small, heat-labile, hydrophilic inhibitor (not ascorbate) which we suggest plays a natural role in the control of wall cross-linking, and thus potentially in the control of cell growth.

Ascorbate promotes carbon tetrachloride-induced hepatic injury in senescence marker protein 30-deficient mice by enhancing inflammation.

PubMed

Ki, Mi-Ran; Lee, Hye-Rim; Park, Jin-Kyu; Hong, Il-Hwa; Han, Seon-Young; You, Sang-Young; Lee, Eun-Mi; Kim, Ah-Young; Lee, Seung-Sook; Jeong, Kyu-Shik

2011-06-01

The genetic deletion of the senescence marker protein 30 (SMP30) gene results in ascorbate deficiency and the premature aging processes in mice. Apparent liver injury of SMP30(-/-) mice was less severe than those of wild type (WT) mice, upon chronic CCl(4) injection. The purpose of this study was to investigate the pathophysiology underlying the mild CCl(4) toxicity in SMP30(-/-) mice. Along with the lower level of serum alanine aminotransferase, the livers of SMP30(-/-) mice revealed a lesser glycogen depletion, a decrease in c-Jun N-terminal kinase (JNK)-mediated inflammatory signaling in parallel with tumor necrosis factor-alpha and interleukin-1 beta, inducible nitric oxide synthase and glutathione peroxidase, and the lower lipid peroxidation as compared to those of WT mice. CCl(4)-induced proliferation, measured by the expression of proliferating cell nuclear antigen, was low in SMP30(-/-) mice as compared with that of WT mice whereas the levels of p21 and Bax were comparable to those of the CCl(4)-treated WT mice. Moreover, CCl(4) toxicity in ascorbate-fed SMP30(-/-) mice was comparable to that of the CCl(4)-alone treated WT mice, accompanied by an increase in the above mentioned factors. Conversely, ascorbate partly compensated for the CCl(4)-induced oxidative stress in WT mice, indicating that sufficient ascorbate may be required for an antioxidant function under severe levels of oxidative stress. Our data suggest that the restoration of ascorbate-deficiency reverses a sluggish immune system into an activated condition by an increase in JNK-mediated inflammation and free radical cascade; thus leading to accelerated hepatic damage in SMP30(-/-) mice. Copyright © 2011 Elsevier Inc. All rights reserved.

Kinetin increases chromium absorption, modulates its distribution, and changes the activity of catalase and ascorbate peroxidase in Mexican Palo Verde

PubMed Central

Zhao, Yong; Peralta-Videa, Jose R.; Lopez-Moreno, Martha L.; Ren, Minghua; Saupe, Geoffrey; Gardea-Torresdey, Jorge L

2015-01-01

This report shows, for the first time, the effectiveness of the phytohormone kinetin (KN) in increasing Cr translocation from roots to stems in Mexican Palo Verde. Fifteen-day-old seedlings, germinated in soil spiked with Cr(III) and (VI) at 60 and 10 mg kg−1, respectively, were watered every other day for 30 days with a KN solution at 250 μM. Samples were analyzed for catalase (CAT) and ascorbate peroxidase (APOX) activities, Cr concentration, and Cr distribution in tissues. Results showed that KN reduced CAT but increased APOX in the roots of Cr(VI)-treated plants. In the leaves, KN reduced both CAT and APOX in Cr(III) but not in Cr(VI)-treated plants. However, KN increased total Cr concentration in roots, stems, and leaves by 45%, 103%, and 72%, respectively, compared to Cr(III) alone. For Cr(VI), KN increased Cr concentrations in roots, stems, and leaves, respectively, by 53%, 129%, and 168%, compared to Cr(VI) alone. The electron probe microanalyzer results showed that Cr was mainly located at the cortex section in the root, and Cr distribution was essentially homogenous in stems. However, proven through X-ray images, Cr(VI)-treated roots and stems had more Cr accumulation than Cr(III) counterparts. KN increased the Cr translocation from roots to stems. PMID:21174467

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

PubMed

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.

Antioxidative response in variegated Pelargonium zonale leaves and generation of extracellular H2O2 in (peri)vascular tissue induced by sunlight and paraquat.

PubMed

Vidović, Marija; Morina, Filis; Prokić, Ljiljana; Milić-Komić, Sonja; Živanović, Bojana; Jovanović, Sonja Veljović

2016-11-01

In this study we exposed variegated leaves of Pelargonium zonale to strong sunlight (>1100μmolm -2 s -1 of photosynthetically active radiation) with and without paraquat (Pq), with the aim to elucidate the mechanisms of H 2 O 2 regulation in green and white tissues with respect to the photosynthetically-dependent generation of reactive oxygen species (ROS). Sunlight induced marked accumulation of H 2 O 2 in the apoplast of vascular and (peri)vascular tissues only in green sectors. This effect was enhanced by the addition of Pq. In the presence of diphenyl iodide, an NADPH oxidase inhibitor, H 2 O 2 accumulation was abolished. Distinct light-induced responses were observed: in photosynthetic cells, sunlight rapidly provoked ascorbate (Asc) biosynthesis and an increase of glutathione reductase (GR) and catalase activities, while in non-photosynthetic cells, early up-regulation of soluble ascorbate peroxidase, dehydroascorbate reductase (DHAR) and GR activities was observed. Paraquat addition stimulated DHAR and GR activities in green sectors, while in white sectors activities of monodehydroascorbate reductase, DHAR and class III peroxidases, as well as Asc content rapidly increased. Differential antioxidative responses in the two tissues in the frame of their contrasting metabolisms, and the possible role of (peri)vascular H 2 O 2 in signaling were discussed. Copyright © 2016 Elsevier GmbH. All rights reserved.

Effects of added CeCl3 on resistance of fifth-instar larvae of silkworm to Bombyx mori nucleopolyhedrovirus infection.

PubMed

Li, Bing; Xie, Yi; Cheng, Zhe; Cheng, Jie; Hu, Rengping; Cui, Yaling; Gong, Xiaolan; Shen, Weide; Hong, Fashui

2012-06-01

One of the most important agents causing lethal disease in the silkworm is the Bombyx mori nucleopolyhedrovirus (BmNPV), while low-dose rare earths are demonstrated to increase immune capacity in animals. However, very little is known about the effects of added CeCl(3) on decreasing BmNPV infection of silkworm. The present study investigated the effects of added CeCl(3) to an artificial diet on resistance of fifth-instar larvae of silkworm to BmNPV infection. Our findings indicated that added CeCl(3) significantly decreased inhibition of growth and mortality of fifth-instar larvae caused by BmNPV infection. Furthermore, the added CeCl(3) obviously decreased lipid peroxidation level and accumulation of reactive oxygen species such as O(2)(-), H(2)O(2), (·)OH, and NO and increased activities of the antioxidant enzymes including superoxide dismutase, catalase, ascorbate peroxidase, glutathione peroxidase, ascorbate, and glutathione contents in the BmNPV-infected fifth-instar larvae. In addition, the added CeCl(3) could significantly promote acetylcholine esterase activity and attenuate the activity of inducible nitric oxide synthase in the BmNPV-infected fifth-instar larvae. These findings suggested that added CeCl(3) may relieve oxidative damage and neurotoxicity of silkworm caused by BmNPV infection via increasing antioxidant capacity and acetylcholine esterase activity.

Modulation of the antioxidative response of Spartina densiflora against iron exposure.

PubMed

Martínez Domínguez, David; Torronteras Santiago, Rafael; Córdoba García, Francisco

2009-06-01

Spartina densiflora, an invader cordgrass living in polluted salt marshes of the Odiel estuary (SW Spain), was collected and cultured under controlled laboratory conditions. After acclimation to non-polluted soils for 28 days, both metabolites and enzymes activities used as indicators of oxidative stress were reduced significantly. Then, plants were exposed to 500 and 1000 ppm Fe-ethylenediamine-N,N'-2-hydroxyphenyl acetic acid (EDDHA) for 28 days. Our data demonstrate that iron content in leaves was enhanced by iron exposure. This iron increase caused an enhancement in the concentration of H2O2, hydroperoxides and lipid peroxidation, and a decrease in chlorophyll levels. Thus, iron exposure led to oxidative stress conditions. However, oxidative indicators stabilised after first 2 weeks of exposure, although the highest iron levels in leaves were reached at the end of treatments. Iron exposure induced an enhancement of catalase, ascorbate peroxidase and guaiacol peroxidase activities, together with an increase in total and oxidised ascorbate. This response may be defensive against oxidative stress and thus help to explain why cell oxidative damages were stabilised. Thus, by using a sensitive long-time protocol, iron-dependent oxidative damages may be controlled and even reverted successfully by the activation of the antioxidative defences of S. densiflora. This efficient antioxidative system, rapidly modulated in response to excess iron and other environmental stressors, may account for S. densiflora's successful adaptation to stress conditions in its habitat.

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

PubMed

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.

Determining inhibition effects of some aromatic compounds on peroxidase enzyme purified from white and red cabbage

NASA Astrophysics Data System (ADS)

Öztekin, Aykut; Almaz, Züleyha; Özdemir, Hasan

2016-04-01

Peroxidases (E.C.1.11.1.7) catalyze the one electron oxidation of wide range of substrates. They are used in synthesis reaction, removal of peroxide from industrial wastes, clinical biochemistry and immunoassays. In this study, the white cabbage (Brassica Oleracea var. capitata f. alba) and red cabbage (Brassica oleracea L. var. capitata f. rubra) peroxidase enzymes were purified for investigation of inhibitory effect of some aromatic compounds on these enzymes. IC50 values and Ki constants were calculated for the molecules of 6-Amino nicotinic hydrazide, 6-Amino-5-bromo nicotinic hydrazide, 2-Amino-5-hydroxy benzohydrazide, 4-Amino-3-hydroxy benzohydrazide on purified enzymes and inhibition type of these molecules were determined. (This research was supported by Ataturk University. Project Number: BAP-2015/98).

Glutathione peroxidase (EC 1.11.1.9) and superoxide dismutase (EC 1.15.1.1) activities in riboflavin-deficient rats infected with Plasmodium berghei malaria.

PubMed

Adelekan, D A; Thurnham, D I

1998-03-01

Riboflavin deficiency interferes with the growth and multiplication of malaria parasites as well as the host response to malaria. The objective of the present work was to determine the effects of riboflavin deficiency on erythrocyte glutathione peroxidase (EC 1.11.1.9; GPx) and superoxide dismutase (EC 1.15.1.1; SOD) in rats infected with Plasmodium berghei malaria. Riboflavin in its co-enzyme form, FAD, is required by glutathione reductase (EC 1.6.4.1) to regenerate GSH and GSH is an important cellular antioxidant both in its own right and also as a substrate for the enzyme GPx. Weanling rats were deprived of riboflavin for 8 weeks before intraperitoneal injection of 1 x 10(6) P. berghei parasites. Control animals were weight-matched to the respective riboflavin-deficient group. At 10 d post-infection, parasite counts were higher in the weight-matched control group than the riboflavin-deficient group (P = 0.004). GPx activity was higher in erythrocytes of rats parasitized with P. berghei than comparable non-infected rats regardless of riboflavin status (P < 0.05). As mature erythrocytes do not synthesize new protein, the higher GPx activities were probably due to the presence of the parasite protein. In erythrocytes from riboflavin-deficient rats, GPx activity tended to be lower than in those rats fed on diets adequate in riboflavin (weight-matched controls) whether parasitized or not, but the difference was not significant. Neither riboflavin deficiency nor malaria had any effect on erythrocyte SOD activity. It was concluded that riboflavin deficiency has no marked effect on erythrocyte GPx or SOD activity in the rat.

Trichoderma harzianum T-78 supplementation of compost stimulates the antioxidant defence system in melon plants.

PubMed

Bernal-Vicente, Agustina; Pascual, José A; Tittarelli, Fabio; Hernández, José A; Diaz-Vivancos, Pedro

2015-08-30

Compost is emerging as an alternative plant growing medium in efforts to achieve more sustainable agriculture. The addition of specific microorganisms such as Trichoderma harzianum to plant growth substrates increases yields and reduces plant diseases, but the mechanisms of such biostimulants and the biocontrol effects are not yet fully understood. In this work we investigated how the addition of citrus and vineyard composts, either alone or in combination with T. harzianum T-78, affects the antioxidant defence system in melon plants under nursery conditions. Compost application and/or Trichoderma inoculation modulated the antioxidant defence system in melon plants. The combination of citrus compost and Trichoderma showed a biostimulant effect that correlated with an increase in ascorbate recycling enzymes (monodehydroascorbate reductase, dehydroascorbate reductase) and peroxidase. Moreover, the inoculation of both composts with Trichoderma increased the activity of antioxidant enzymes, especially those involved in ascorbate recycling. Based on the long-established relationship between ascorbic acid and plant defence responses as well as plant growth and development, it can be suggested that ascorbate recycling activities play a major role in the protection provided by Trichoderma and its biostimulant effect and that these outcomes are linked to increases in antioxidant enzymes. We can conclude that the combination of citrus compost and T. harzianum T-78 constitutes a viable, environmentally friendly strategy for improving melon plant production. © 2014 Society of Chemical Industry.

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

PubMed

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

2012-11-01

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.

Prospecting Russula senecis: a delicacy among the tribes of West Bengal

PubMed Central

Khatua, Somanjana; Dutta, Arun Kumar

2015-01-01

Russula senecis, a worldwide distributed mushroom, is exclusively popular among the tribal communities of West Bengal for food purposes. The present study focuses on its reliable taxonomic identification through macro- and micro-morphological features, DNA barcoding, confirmation of its systematic placement by phylogenetic analyses, myco-chemicals and functional activities. For the first time, the complete Internal Transcribed Spacer region of R. senecis has been sequenced and its taxonomic position within subsection Foetentinae under series Ingratae of the subgen. Ingratula is confirmed through phylogenetic analysis. For exploration of its medicinal properties, dried basidiocarps were subjected for preparation of a heat stable phenol rich extract (RusePre) using water and ethanol as solvent system. The antioxidant activity was evaluated through hydroxyl radical scavenging (EC50 5 µg/ml), chelating ability of ferrous ion (EC50 0.158 mg/ml), DPPH radical scavenging (EC50 1.34 mg/ml), reducing power (EC50 2.495 mg/ml) and total antioxidant activity methods (13.44 µg ascorbic acid equivalent/mg of extract). RusePre exhibited antimicrobial potentiality against Listeria monocytogenes, Bacillus subtilis, Pseudomonas aeruginosa and Staphylococcus aureus. Furthermore, different parameters were tested to investigate its chemical composition, which revealed the presence of appreciable quantity of phenolic compounds, along with carotenoids and ascorbic acid. HPLC-UV fingerprint indicated the probable existence of at least 13 phenolics, of which 10 were identified (pyrogallol > kaempferol > quercetin > chlorogenic acid > ferulic acid, cinnamic acid > vanillic acid > salicylic acid > p-coumaric acid > gallic acid). Result from the present work suggests that the fraction, RusePre, may open novel prospect as a functional ingredient in antioxidant supplements and in drugs to treat infectious disease. PMID:25780764

Progress in utilisation of graphene for electrochemical biosensors.

PubMed

Lawal, Abdulazeez T

2018-05-30

This review discusses recent graphene (GR) electrochemical biosensor for accurate detection of biomolecules, including glucose, hydrogen peroxide, dopamine, ascorbic acid, uric acid, nicotinamide adenine dinucleotide, DNA, metals and immunosensor through effective immobilization of enzymes, including glucose oxidase, horseradish peroxidase, and haemoglobin. GR-based biosensors exhibited remarkable performance with high sensitivities, wide linear detection ranges, low detection limits, and long-term stabilities. Future challenges for the field include miniaturising biosensors and simplifying mass production are discussed. Copyright © 2018 Elsevier B.V. All rights reserved.

An enhancing effect of visible light and UV radiation on phenolic compounds and various antioxidants in broad bean seedlings.

PubMed

Younis, Mahmoud El-Baz; Hasaneen, Mohammed Naguib Abdel-Ghany; Abdel-Aziz, Heba Mahmoud Mohammed

2010-10-01

Exposure of dark- or ambient visible light-grown broad bean seedlings to low (LL) and high (HL) visible light intensities, UV-A or UV-C, either alone or in combination, induced significant increases in total phenolic compounds as well as in anthocyanins content, throughout the germination period, as compared with the respective levels in control seedlings. In general, as compared with control levels, exposure of both dark- or light-grown broad bean seedlings to LL, HL, UV-A or UV-C, induced significant increases in the contents of non-enzymatic antioxidants (total ascorbate; ASA-DASA and total glutathione; GSSG-GSH) and enzymatic antioxidant activities (superoxide dismutase; SOD, catalase; CAT, ascorbate peroxidase; APO and glutathione reductase; GR). The obtained results are discussed in relation to induced mechanisms of protection and repair from the inevitable exposure to damaging visible light and UV-radiation. © 2010 Landes Bioscience

An enhancing effect of visible light and UV radiation on phenolic compounds and various antioxidants in broad bean seedlings

PubMed Central

Hasaneen, Mohammed Naguib Abdel-Ghany; Abdel-Aziz, Heba Mahmoud Mohammed

2010-01-01

Exposure of dark- or ambient visible light-grown broad bean seedlings to low (LL) and high (HL) visible light intensities, UV-A or UV-C, either alone or in combination, induced significant increases in total phenolic compounds as well as in anthocyanins content, throughout the germination period, as compared with the respective levels in control seedlings. In general, as compared with control levels, exposure of both dark- or light-grown broad bean seedlings to LL, HL, UV-A or UV-C, induced significant increases in the contents of non-enzymatic antioxidants (total ascorbate; ASA-DASA and total glutathione; GSSG-GSH) and enzymatic antioxidant activities (superoxide dismutase; SOD, catalase; CAT, ascorbate peroxidase; APO and glutathione reductase; GR). The obtained results are discussed in relation to induced mechanisms of protection and repair from the inevitable exposure to damaging visible light and UV radiation. PMID:20505357

Anti-Oxidative Defences Are Modulated Differentially in Three Freshwater Teleosts in Response to Ammonia-Induced Oxidative Stress

PubMed Central

Giblen, Terri; Zinta, Gaurav; De Rop, Michelle; Asard, Han; Blust, Ronny; De Boeck, Gudrun

2014-01-01

Oxidative stress and the antioxidant response induced by high environmental ammonia (HEA) were investigated in the liver and gills of three freshwater teleosts differing in their sensitivities to ammonia. The highly ammonia-sensitive salmonid Oncorhynchus mykiss (rainbow trout), the less ammonia sensitive cyprinid Cyprinus carpio (common carp) and the highly ammonia-resistant cyprinid Carassius auratus (goldfish) were exposed to 1 mM ammonia (as NH4HCO3) for 0 h (control), 3 h, 12 h, 24 h, 48 h, 84 h and 180 h. Results show that HEA exposure increased ammonia accumulation significantly in the liver of all the three fish species from 24 h–48 h onwards which was associated with an increment in oxidative stress, evidenced by elevation of xanthine oxidase activity and levels of hydrogen peroxide (H2O2) and malondialdehyde (MDA). Unlike in trout, H2O2 and MDA accumulation in carp and goldfish liver was restored to control levels (84 h–180 h); which was accompanied by a concomitant increase in superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase activity and reduced ascorbate content. Many of these defence parameters remained unaffected in trout liver, while components of the glutathione redox cycle (reduced glutathione, glutathione peroxidase and glutathione reductase) enhanced to a greater extent. The present findings suggest that trout rely mainly on glutathione dependent defensive mechanism while carp utilize SOD, CAT and ascorbate as anti-oxidative sentinels. Hepatic cells of goldfish appear to utilize each of these protective systems, and showed more effective anti-oxidative compensatory responses towards HEA than carp, while trout were least effective. The present work also indicates that HEA exposure resulted in a relatively mild oxidative stress in the gills of all three species. This probably explains the almost complete lack of anti-oxidative responses in branchial tissue. This research suggests that oxidative stress, as well as the antioxidant potential clearly differ between salmonid and cyprinid species. PMID:24740135

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

PubMed

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.

Determining inhibition effects of some aromatic compounds on peroxidase enzyme purified from white and red cabbage

DOE Office of Scientific and Technical Information (OSTI.GOV)

Öztekin, Aykut, E-mail: aoztekin@agri.edu.tr; Agri Ibrahim Cecen University Faculty of Arts and Sciences, Department of Chemistry, 04100-Agri; Almaz, Züleyha, E-mail: zturkoglu-2344@hotmail.com

2016-04-18

Peroxidases (E.C.1.11.1.7) catalyze the one electron oxidation of wide range of substrates. They are used in synthesis reaction, removal of peroxide from industrial wastes, clinical biochemistry and immunoassays. In this study, the white cabbage (Brassica Oleracea var. capitata f. alba) and red cabbage (Brassica oleracea L. var. capitata f. rubra) peroxidase enzymes were purified for investigation of inhibitory effect of some aromatic compounds on these enzymes. IC{sub 50} values and Ki constants were calculated for the molecules of 6-Amino nicotinic hydrazide, 6-Amino-5-bromo nicotinic hydrazide, 2-Amino-5-hydroxy benzohydrazide, 4-Amino-3-hydroxy benzohydrazide on purified enzymes and inhibition type of these molecules were determined. (Thismore » research was supported by Ataturk University. Project Number: BAP-2015/98).« less

The missing step of the L-galactose pathway of ascorbate biosynthesis in plants, an L-galactose guanyltransferase, increases leaf ascorbate content.

PubMed

Laing, William A; Wright, Michele A; Cooney, Janine; Bulley, Sean M

2007-05-29

The gene for one postulated enzyme that converts GDP-L-galactose to L-galactose-1-phosphate is unknown in the L-galactose pathway of ascorbic acid biosynthesis and a possible candidate identified through map-based cloning is the uncharacterized gene At4g26850. We identified a putative function for At4g26850 using PSI-Blast and motif searching to show it was a member of the histidine triad superfamily, which includes D-galactose uridyltransferase. We cloned and expressed this Arabidopsis gene and the homologous gene from Actinidia chinensis in Escherichia coli and assayed the expressed protein for activities related to converting GDP-L-galactose to L-galactose-1-P. The expressed protein is best described as a GDP-L-galactose-hexose-1-phosphate guanyltransferase (EC 2.7.7.), catalyzing the transfer of GMP from GDP-l-galactose to a hexose-1-P, most likely D-mannose-1-phosphate in vivo. Transient expression of this A. chinensis gene in tobacco leaves resulted in a >3-fold increase in leaf ascorbate as well as a 50-fold increase in GDP-L-galactose-D-mannose-1-phosphate guanyltransferase activity.

The missing step of the l-galactose pathway of ascorbate biosynthesis in plants, an l-galactose guanyltransferase, increases leaf ascorbate content

PubMed Central

Laing, William A.; Wright, Michele A.; Cooney, Janine; Bulley, Sean M.

2007-01-01

The gene for one postulated enzyme that converts GDP-l-galactose to l-galactose-1-phosphate is unknown in the l-galactose pathway of ascorbic acid biosynthesis and a possible candidate identified through map-based cloning is the uncharacterized gene At4g26850. We identified a putative function for At4g26850 using PSI-Blast and motif searching to show it was a member of the histidine triad superfamily, which includes d-galactose uridyltransferase. We cloned and expressed this Arabidopsis gene and the homologous gene from Actinidia chinensis in Escherichia coli and assayed the expressed protein for activities related to converting GDP-l-galactose to l-galactose-1-P. The expressed protein is best described as a GDP-l-galactose-hexose-1-phosphate guanyltransferase (EC 2.7.7.), catalyzing the transfer of GMP from GDP-l-galactose to a hexose-1-P, most likely d-mannose-1-phosphate in vivo. Transient expression of this A. chinensis gene in tobacco leaves resulted in a >3-fold increase in leaf ascorbate as well as a 50-fold increase in GDP-l-galactose-d-mannose-1-phosphate guanyltransferase activity. PMID:17485667

Genome-wide investigation and expression profiling of APX gene family in Gossypium hirsutum provide new insights in redox homeostasis maintenance during different fiber development stages.

PubMed

Tao, Chengcheng; Jin, Xiang; Zhu, Liping; Xie, Quanliang; Wang, Xuchu; Li, Hongbin

2018-06-01

Ascorbate peroxidase (APX) is a member of heme-containing peroxidases which catalyze the H 2 O 2 -dependent oxidation of a wide range of substrates in plants and animals. As is known, H 2 O 2 acts as a signaling molecule in the regulation of fiber development. Our previous work reported that ascorbate peroxidase 1 (GhAPX1) was important for cotton fiber elongation. However, knowledge about APX gene family members and their evolutionary and functional characteristics in cotton is limited. Here, we report 26 GhAPX genes by genome-wide investigation of tetraploid cotton Gossypium hirsutum. Phylogenetic and gene structure analyses classified these APX members into five clades and syntenic analysis suggested two duplication events. Expression profiling of the 26 APXs revealed that ten members are expressed in cotton fibers. Notably, GhAPX10A, GhAPX10D, GhAPX12A, and GhAPX12D showed high expression levels in 30-day fiber, while GhAPX1A/D, GhAPX3A/D, and GhAPX6A/D showed very low expression levels. The enzyme activity and H 2 O 2 content assays revealed that cotton fiber kept high enzyme activity and the lowest H 2 O 2 level in 30-day fibers, indicating that other than GhAPX1, the newly reported APX members are responsible for the reactive oxygen species homeostasis in the cotton fiber maturation stages. Expression profiling of ten fiber-expressed APXs after phytohormone treatments revealed their regulation patterns by different stimuli, suggesting that GhAPX1, GhAPX12A, and GhAPX12D are responsible to most phytohormone treatments. Our data provided evolutionary and functional information of GhAPX gene family members and revealed that different members are responsible to redox homeostasis during different cotton fiber development stages.

Nucleotide sequences of two genomic DNAs encoding peroxidase of Arabidopsis thaliana.

PubMed

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.

Susceptibility against grey blight disease-causing fungus Pestalotiopsis sp. in tea (Camellia sinensis (L.) O. Kuntze) cultivars is influenced by anti-oxidative enzymes.

PubMed

Palanisamy, Senthilkumar; Mandal, Abul Kalam Azad

2014-01-01

Reactive oxygen species (ROS) production is the first level of response by a host during stress. Even though the ROS are toxic to cell, when present in a limited amount, they act as a signalling molecule for the expression of defence-related genes and later are scavenged by either enzymatic or non-enzymatic mechanisms of the host. The different anti-oxidative enzymes like glutathione reductase (GR), superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APO), peroxidase (POD) and polyphenol oxidase (PPO) were estimated, and their activities were compared between infected and healthy leaves of the tolerant and susceptible cultivars of tea. The infected leaves of the susceptible cultivars registered higher amount of enzyme activity when compared with the tolerant cultivars. The study reveals that the more anti-oxidative enzymes, the more susceptible the cultivar will be.

Antioxidant response to metal pollution in Phragmites australis from Anzali wetland.

PubMed

Esmaeilzadeh, Marjan; Karbassi, Abdolreza; Bastami, Kazem Darvish

2017-06-15

This research was conducted to examine variations of antioxidant enzyme activity in Phragmites australis as a biomarker for metals such as As, Pb, Cu, and Cd. Samples of sediment and plants were collected from 7 stations located in Anzali wetland. Biochemical parameters including Catalase, Peroxidase and Ascorbate Peroxidase activity were analyzed in the roots, stems and leaves of P. australis. The obtained results indicated that there were significant differences among activities of antioxidant enzymes in three organs (p<0.05). Antioxidant enzyme activities in the organs for all studied stations were as the following order: stem

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

PubMed

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

Functional roles of flavonoids in photoprotection: new evidence, lessons from the past.

PubMed

Agati, Giovanni; Brunetti, Cecilia; Di Ferdinando, Martina; Ferrini, Francesco; Pollastri, Susanna; Tattini, Massimiliano

2013-11-01

We discuss on the relative significance of different functional roles potentially served by flavonoids in photoprotection, with special emphasis to their ability to scavenge reactive oxygen species (ROS) and control the development of individual organs and whole plant. We propose a model in which chloroplast-located flavonoids scavenge H2O2 and singlet oxygen generated under excess light-stress, thus avoiding programmed cell death. We also draw a picture in which vacuolar flavonoids in conjunction with peroxidases and ascorbic acid constitute a secondary antioxidant system aimed at detoxifying H2O2, which may diffuse out of the chloroplast at considerable rates and enter the vacuole following excess light stress-induced depletion of ascorbate peroxidase. We hypothesize for flavonols key roles as developmental regulators in early and current-day land-plants, based on their ability to modulate auxin movement and auxin catabolism. We show that antioxidant flavonoids display the greatest capacity to regulate key steps of cell growth and differentiation in eukaryotes. These regulatory functions of flavonoids, which are shared by plants and animals, are fully accomplished in the nM concentration range, as likely occurred in early land plants. We therefore conclude that functions of flavonoids as antioxidants and/or developmental regulators flavonoids are of great value in photoprotection. We also suggest that UV-B screening was just one of the multiple functions served by flavonoids when early land-plants faced an abrupt increase in sunlight irradiance. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

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.

PubMed

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.

Superoxide and Singlet Oxygen Produced within the Thylakoid Membranes Both Cause Photosystem I Photoinhibition.

PubMed

Takagi, Daisuke; Takumi, Shigeo; Hashiguchi, Masaki; Sejima, Takehiro; Miyake, Chikahiro

2016-07-01

Photosystem I (PSI) photoinhibition suppresses plant photosynthesis and growth. However, the mechanism underlying PSI photoinhibition has not been fully clarified. In this study, in order to investigate the mechanism of PSI photoinhibition in higher plants, we applied repetitive short-pulse (rSP) illumination, which causes PSI-specific photoinhibition in chloroplasts isolated from spinach leaves. We found that rSP treatment caused PSI photoinhibition, but not PSII photoinhibition in isolated chloroplasts in the presence of O2 However, chloroplastic superoxide dismutase and ascorbate peroxidase activities failed to protect PSI from its photoinhibition. Importantly, PSI photoinhibition was largely alleviated in the presence of methyl viologen, which stimulates the production of reactive oxygen species (ROS) at the stromal region by accepting electrons from PSI, even under the conditions where CuZn-superoxide dismutase and ascorbate peroxidase activities were inactivated by KCN. These results suggest that the ROS production site, but not the ROS production rate, is critical for PSI photoinhibition. Furthermore, we found that not only superoxide (O2 (-)) but also singlet oxygen ((1)O2) is involved in PSI photoinhibition induced by rSP treatment. From these results, we suggest that PSI photoinhibition is caused by both O2 (-) and (1)O2 produced within the thylakoid membranes when electron carriers in PSI become highly reduced. Here, we show, to our knowledge, new insight into the PSI photoinhibition in higher plants. © 2016 American Society of Plant Biologists. All Rights Reserved.

Excess copper induced oxidative stress and response of antioxidants in rice.

PubMed

Thounaojam, Thorny Chanu; Panda, Piyalee; Panda, P; Mazumdar, Purabi; Mazumdar, P; Kumar, Devanand; Sharma, Gauri Dutta; Sharma, G D; Sahoo, Lingaraj; Sahoo, L; Panda, Sanjib Kumar; Panda, S K

2012-04-01

To investigate the effects of copper (Cu), rice plant (Oryza sativa. L. var. MSE-9) was treated with different Cu concentrations (0, 10, 50 and 100 μM) for 5 days in hydroponic condition. Gradual decrease in shoot and root growth was observed with the increase of Cu concentration and duration of treatment where maximum inhibition was recorded in root growth. Cu was readily absorbed by the plant though the maximum accumulation was found in root than shoot. Hydrogen peroxide (H(2)O(2)) production and lipid peroxidation were found increased with the elevated Cu concentration indicating excess Cu induced oxidative stress. Antioxidant enzymes superoxide dismutase (SOD), guaiacol peroxidase (GPX) and ascorbate peroxidase (APX) and glutathione reductase (GR) were effectively generated at the elevated concentrations of Cu though catalase (CAT) did not show significant variation with respect to control. Ascorbate (ASH), glutathione (GSH) and proline contents were also increased in all the Cu treated plants compared with the control. SOD isoenzyme was greatly affected by higher concentration of Cu and it was consistent with the changes of the activity assayed in solution. The present study confirmed that excess Cu inhibits growth, induced oxidative stress by inducing ROS formation while the stimulated antioxidative system appears adaptive response of rice plant against Cu induced oxidative stress. Moreover proline accumulation in Cu stress plant seems to provide additional defense against the oxidative stress. Copyright © 2012 Elsevier Masson SAS. All rights reserved.

Are Natural Ingredients Effective in the Management of Hyperpigmentation? A Systematic Review

PubMed Central

Angra, Kunal; Halder, Rebat M.

2018-01-01

BACKGROUND: Hyperpigmentation disorders are commonly encountered in dermatology clinics. Botanical and natural ingredients have gained popularity as alternative depigmenting products. OBJECTIVE: We sought to review clinical studies evaluating the use of different natural products in treating hyperpigmentation so clinicians are better equipped to educate their patients. Specific ingredients reviewed include azelaic acid, aloesin, mulberry, licorice extracts, lignin peroxidase, kojic acid, niacinamide, ellagic acid, arbutin, green tea, turmeric, soy, and ascorbic acid. METHODS: Systematic searches of PubMed and SCOPUS databases were performed in March 2016 using the various ingredient names, “melasma”and “hyperpigmentation.” Two reviewers independently screened titles, leading to the selection of 30 clinical studies. RESULTS: Review of the literature revealed few clinical trials that evaluated the treatment of hyperpigmentation with natural ingredients. Despite the limited evidence-based research, several natural ingredients did show efficacy as depigmenting agents, including azelaic acid, soy, lignin peroxidase, ascorbic acid iontophoresis, arbutin, ellagic acid, licorice extracts, niacinamide, and mulberry. CONCLUSION: The aforementioned ingredients show promise as natural treatments for patients with hyperpigmentation disorders. These agents might also provide clinicians and researchers with a way to further characterize the pathogenesis of dyschromia. However, the paucity of clinical studies is certainly a limitation. Additionally, many of the in-vivo studies are limited by the short length of the trials, and questions remain about the long-term efficacy and safety of the ingredients used in these studies. Lastly, we suggest a standardized objective scoring system be implemented in any further comparative studies. PMID:29552273

Photoinactivation of ascorbate peroxidase in isolated tobacco chloroplasts: Galdieria partita APX maintains the electron flux through the water-water cycle in transplastomic tobacco plants.

PubMed

Miyake, Chikahiro; Shinzaki, Yuki; Nishioka, Minori; Horiguchi, Sayaka; Tomizawa, Ken-Ichi

2006-02-01

We evaluated the H2O2-scavenging activity of the water-water cycle (WWC) in illuminated intact chloroplasts isolated from tobacco leaves. Illumination under conditions that limited photosynthesis [red light (>640 nm), 250 micromol photons m(-2) s(-1) in the absence of HCO3-] caused chloroplasts to take up O2 and accumulate H2O2. Concomitant with the O2 uptake, both ascorbate peroxidase (APX) and glyceraldehyde 3-phosphate dehydrogenase (GAPDH) lost their activities. However, superoxide dismutase (SOD), monodehydroascorbate radical reductase (MDAR), dehydroascorbate reductase (DHAR) and glutathione reductase (GR) activities remained unaffected. The extent to which the photosynthetic linear electron flow decreased was small compared with the decline in APX activity. Therefore, the loss of APX activity lowered the electron flux through the WWC, as evidenced by a decrease in relative electron flux through PSII [Phi(PSII)xPFD]. To verify these interpretations, we created a transplastomic tobacco line in which an H2O2-insensitive APX from the red alga, Galdieria partita, was overproduced in the chloroplasts. In intact transplastomic chloroplasts which were illuminated under conditions that limited photosynthesis, neither O2 uptake nor H2O2 accumulation occurred. Furthermore, the electron flux through the WWC and the activity of GAPDH were maintained. The present work is the first report of APX inactivation by endogenous H2O2 in intact chloroplasts.

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

PubMed

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.

Cultivar specific variations in antioxidative defense system, genome and proteome of two tropical rice cultivars against ambient and elevated ozone.

PubMed

Sarkar, Abhijit; Singh, Aditya Abha; Agrawal, Shashi Bhushan; Ahmad, Altaf; Rai, Shashi Pandey

2015-05-01

For the past few decades continuous increase in the levels of tropospheric ozone (O3) concentrations is posing to be a threat for agricultural productivity. Two high yielding tropical rice cultivars (Malviya dhan 36 and Shivani) were evaluated against different concentrations of O3 under field conditions. Experimental design included filtered chambers, non-filtered chambers having ambient O3 and 10 and 20ppb elevated O3 above the ambient. Study was conducted to assess differential response if any in induction of antioxidative defense system, genome stability, leaf proteome, yield and quality of the product in both the test cultivars. Superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), ascorbate peroxidase (APX), and glutathione reductase (GR) were induced under ambient and elevated levels of O3. Native polyacrylamide gel electrophoresis (PAGE) of SOD, CAT and POD also displayed increased enzymatic activity along with associated alterations in specific isoforms. Ascorbic acid, thiols and phenolics were also stimulated at ambient and elevated O3. Structural alterations in DNA of rice plants due to O3 affecting its genome template stability (GTS) was examined using RAPD technique. 2-D PAGE revealed 25 differential spots in Malviya dhan 36 and 36 spots in Shivani after O3 treatment with reductions in RuBisCO subunits. Reductions in yield and change in the quality of grains were also noticed. Copyright © 2015 Elsevier Inc. All rights reserved.

Inhibitory action on the production of advanced glycation end products (AGEs) and suppression of free radicals in vitro by a Sri Lankan polyherbal formulation Nawarathne Kalka.

PubMed

Fernando, Chamira Dilanka; Karunaratne, Diyathi Tharindhi; Gunasinghe, Sachith Dilshan; Cooray, M C Dilusha; Kanchana, Prabuddhi; Udawatte, Chandani; Perera, Pathirage Kamal

2016-07-08

Advanced glycation end products (AGEs) and free radicals are inflammatory mediators and are implicated in many diseases such as diabetes, cancer, rheumatoid arthritis etc. Multi targeted poly herbal drug systems like Nawarathne Kalka (NK) are able to quench the overall effect of these mediators as they contain good combinations of phytochemicals that have least side effects in contrast to modern medicinal drugs. The objectives of this study were to evaluate phytochemical composition, free radical scavenging activity, cytotoxicity and the inhibitory action on the formation of AGEs by aqueous extract of NK. Total phenolic content (TPC) and total flavonoid content (TFC) were determined using Folin ciocalteu method and aluminium chloride assay respectively. Free radical scavenging activity was assessed by DPPH radical scavenging assay (DRSA), phosphomolybdenum reduction antioxidant assay (PRAA) and nitric oxide (NO) scavenging assay. Brine Shrimp Lethality (BSL) bioassay was performed as preliminary screening for cytotoxic activity. Inhibitory action on AGE formation was evaluated using fructose mediated glycation of bovine serum albumin using fluorescence spectroscopic method. The TPC and TFC were 75.1 ± 3.0 mg/g gallic acid equivalents and 68.7 ± 7.8 mg/g epigallocatechin gallate equivalents. The DRSA yielded EC50 of 19.15 ± 2.24 μg mL(-1) for NK. DRSA of NK extract was greater than butylated hydroxy toluene (EC50 = 96.50 ± 4.51 μg mL(-1)) but lesser than L-ascorbic acid (EC50 = 5.60 ± 0.51 μg mL(-1)). The total antioxidant capacity of NK as evidenced by PRAA was 106.4 ± 8.2 mg/g L-ascorbic acid equivalents. NK showed EC50 value of 99.3 ± 8.4 μg mL(-1) in the NO scavenging assay compared to the standard ascorbic acid (EC50 = 7.3 ± 0.3 μg mL(-1)). The extract indicated moderate cytotoxic activity in the BSL bioassay. The extract showed effective inhibitory action on the formation of AGEs with EC50 values of 116 ± 19 μg mL(-1), 125 ± 35 μg mL(-1) and 84 ± 28 μg mL(-1) in data obtained over three consecutive weeks respectively. Comparatively the reference standard, aminoguanidine at a concentration of 500 μg mL(-1) demonstrated 65 % inhibition on the formation of AGE after one week of sample incubation. The results proved the potential of NK as a free radical scavenger, moderate cytotoxic agent and an inhibitor on the formation of advanced glycation end-products.

Cancer cell detection and therapeutics using peroxidase-active nanohybrid of gold nanoparticle-loaded mesoporous silica-coated graphene.

PubMed

Maji, Swarup Kumar; Mandal, Amal Kumar; Nguyen, Kim Truc; Borah, Parijat; Zhao, Yanli

2015-05-13

Development of efficient artificial enzymes is an emerging field in nanobiotechnology, since these artificial enzymes could overcome serious disadvantages of natural enzymes. In this work, a new nanostructured hybrid was developed as a mimetic enzyme for in vitro detection and therapeutic treatment of cancer cells. The hybrid (GSF@AuNPs) was prepared by the immobilization of gold nanoparticles (AuNPs) on mesoporous silica-coated nanosized reduced graphene oxide conjugated with folic acid, a cancer cell-targeting ligand. The GSF@AuNPs hybrid showed unprecedented peroxidase-like activity, monitored by catalytic oxidation of a typical peroxidase substrate, 3,3',5,5'-tetramethylbenzidine (TMB), in the presence of H2O2. On basis of this peroxidase activity, the hybrid was utilized as a selective, quantitative, and fast colorimetric detection probe for cancer cells. Finally, the hybrid as a mimetic enzyme was employed for H2O2- and ascorbic acid (AA)-mediated therapeutics of cancer cells. In vitro experiments using human cervical cancer cells (HeLa cells) exhibited the formation of reactive oxygen species (OH(•) radical) in the presence of peroxidase-mimic GSF@AuNPs with either exogenous H2O2 or endogenous H2O2 generated from AA, leading to an enhanced cytotoxicity to HeLa cells. In the case of normal cells (human embryonic kidney HEK 293 cells), the treatment with the hybrid and H2O2 or AA showed no obvious damage, proving selective killing effect of the hybrid to cancer cells.

Response of mitochondrial antioxidant system and respiratory pathways to reactive nitrogen species in pea leaves.

PubMed

Martí, María C; Florez-Sarasa, Igor; Camejo, Daymi; Pallol, Beatriz; Ortiz, Ana; Ribas-Carbó, Miquel; Jiménez, Ana; Sevilla, Francisca

2013-02-01

Nitric oxide (NO) has emerged as an important signaling molecule in plants, but little is known about the effects of reactive nitrogen species in plant mitochondria. In this study, the effects of DETA-NONOate, a pure NO slow generator, and of SIN-1 (3-morpholinosydnonimine), a peroxynitrite producer, on the activities of respiratory pathways, enzymatic and non-enzymatic antioxidants have been investigated in isolated mitochondria from pea leaves. No significant changes in lipid peroxidation, protein oxidation or in ascorbate and glutathione redox state were observed after DETA-NONOate treatments whereas cytochrome pathway (CP) respiration was reversibly inhibited and alternative pathway (AP) respiration showed little inhibition. On the other hand, NO did not affect neither activities of Mn superoxide dismutase (Mn-SOD) nor enzymes involved in the ascorbate and glutathione regeneration in mitochondria except for ascorbate peroxidase (APX), which was reversely inhibited depending on ascorbate concentration. Finally, SIN-1 treatment of mitochondria produced a decrease in CP respiration, an increase in protein oxidation and strongly inhibited APX activity (90%), with glutathione reductase and dehydroascorbate reductase (DHAR) being moderately inhibited (30 and 20%, respectively). This treatment did not affect monodehydroascorbate reductase (MDHAR) and Mn-SOD activities. Results showed that mitochondrial nitrosative stress was not necessarily accompanied by oxidative stress. We suggest that NO-resistant AP and mitochondrial APX may be important components of the H(2) O(2) -signaling pathways under nitrosative stress induced by NO in this organelle. Also, MDHAR and DHAR, via ascorbate regeneration, could constitute an essential antioxidant defense together with Mn-SOD, against NO and ONOO(-) stress in plant mitochondria. Copyright © Physiologia Plantarum 2012.

Sulfur Deprivation Results in Oxidative Perturbation in Chlorella sorokiniana (211/8k).

PubMed

Salbitani, Giovanna; Vona, Vincenza; Bottone, Claudia; Petriccione, Milena; Carfagna, Simona

2015-05-01

Sulfur deficiency in plant cells has not been considered as a potential abiotic factor that can induce oxidative stress. We studied the antioxidant defense system of Chlorella sorokiniana cultured under sulfur (S) deficiency, imposed for a maximum period of 24 h, to evaluate the effect of an S shortage on oxidative stress. S deprivation induced an immediate (30 min) but transient increase in the intracellular H2O2 content, which suggests that S limitation can lead to a temporary redox disturbance. After 24 h, S deficiency in Chlorella cells decreased the glutathione content to <10% of the value measured in cells that were not subjected to S deprivation. Consequently, we assumed that the cellular antioxidative mechanisms could be altered by a decrease in the total glutathione content. The total ascorbate pool increased within 2 h after the initiation of S depletion, and remained high until 6 h; however, ascorbate regeneration was inhibited under limited S conditions, indicated by a significant decrease in the ascorbate/dehydroascorbate (AsA/DHA) ratios. Furthermore, ascorbate peroxidase (APX) and superoxide dismutase (SOD) were activated under S deficiency, but we assumed that these enzymes were involved in maintaining the cellular H2O2 balance for at least 4 h after the initiation of S starvation. We concluded that S deprivation triggers redox changes and induces antioxidant enzyme activities in Chlorella cells. The accumulation of total ascorbate, changes in the reduced glutathione/oxidized glutathione (GSH/GSSG) ratios and an increase in the activity of SOD and APX enzymes indicate that oxidative perturbation occurs during S deprivation. © The Author 2015. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.

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

PubMed Central

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

2012-01-01

We have previously reported that radon inhalation activates anti-oxidative functions and inhibits carbon tetrachloride (CCl4)-induced hepatopathy. It has also been reported that antioxidant vitamins can inhibit CCl4-induced hepatopathy. In the current study, we examined the comparative efficacy of treatment with radon, ascorbic acid and α-tocopherol on CCl4-induced hepatopathy. Mice were subjected to intraperitoneal injection of CCl4 after inhaling approximately 1000 or 2000 Bq/m3 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 CCl4-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 CCl4 alone. These findings suggest that radon inhalation has an anti-oxidative effect against CCl4-induced hepatopathy similar to the anti-oxidative effects of ascorbic acid or α-tocopherol due to the induction of anti-oxidative functions. PMID:23111757

Role of the Ascorbate-Glutathione Cycle of Mitochondria and Peroxisomes in the Senescence of Pea Leaves1

PubMed Central

Jiménez, Ana; Hernández, José A.; Pastori, Gabriela; del Río, Luis A.; Sevilla, Francisca

1998-01-01

We investigated the relationship between H2O2 metabolism and the senescence process using soluble fractions, mitochondria, and peroxisomes from senescent pea (Pisum sativum L.) leaves. After 11 d of senescence the activities of Mn-superoxide dismutase, dehydroascorbate reductase (DHAR), and glutathione reductase (GR) present in the matrix, and ascorbate peroxidase (APX) and monodehydroascorbate reductase (MDHAR) activities localized in the mitochondrial membrane, were all substantially decreased in mitochondria. The mitochondrial ascorbate and dehydroascorbate pools were reduced, whereas the oxidized glutathione levels were maintained. In senescent leaves the H2O2 content in isolated mitochondria and the NADH- and succinate-dependent production of superoxide (O2·−) radicals by submitochondrial particles increased significantly. However, in peroxisomes from senescent leaves both membrane-bound APX and MDHAR activities were reduced. In the matrix the DHAR activity was enhanced and the GR activity remained unchanged. As a result of senescence, the reduced and the oxidized glutathione pools were considerably increased in peroxisomes. A large increase in the glutathione pool and DHAR activity were also found in soluble fractions of senescent pea leaves, together with a decrease in GR, APX, and MDHAR activities. The differential response to senescence of the mitochondrial and peroxisomal ascorbate-glutathione cycle suggests that mitochondria could be affected by oxidative damage earlier than peroxisomes, which may participate in the cellular oxidative mechanism of leaf senescence longer than mitochondria. PMID:9847106

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ourique, Fabiana; Kviecinski, Maicon R.; Zirbel, Guilherme

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, p16more » 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 reduced glucose uptake. • Treatments induced cell cycle arrest and apoptosis in tumor in vivo.« less

Salicylic Acid and Ethylene Pathways Are Differentially Activated in Melon Cotyledons by Active or Heat-Denatured Cellulase from Trichoderma longibrachiatum

PubMed Central

Martinez, Christelle; Blanc, Frédéric; Le Claire, Emilie; Besnard, Olivier; Nicole, Michel; Baccou, Jean-Claude

2001-01-01

Infiltration of cellulase (EC 3.2.1.4) from Trichoderma longibrachiatum into melon (Cucumis melo) cotyledons induced several key defense mechanisms and hypersensitive reaction-like symptoms. An oxidative burst was observed 3 hours after treatment and was followed by activation of ethylene and salicylic acid (SA) signaling pathways leading to marked induction of peroxidase and chitinase activities. The treatment of cotyledons by heat-denatured cellulase also led to some induction of peroxidase and chitinase activities, but the oxidative burst and SA production were not observed. Co-infiltration of aminoethoxyvinil-glycine (an ethylene inhibitor) with the active cellulase did not affect the high increase of peroxidase and chitinase activities. In contrast, co-infiltration of aminoethoxyvinil-glycine with the denatured enzyme blocked peroxidase and chitinase activities. Our data suggest that the SA pathway (induced by the cellulase activity) and ethylene pathway (induced by heat-denatured and active protein) together coordinate the activation of defense mechanisms. We found a partial interaction between both signaling pathways since SA caused an inhibition of the ethylene production and a decrease in peroxidase activity when co-infiltrated with denatured cellulase. Treatments with active or denatured cellulase caused a reduction in powdery mildew (Sphaerotheca fuliginea) disease. PMID:11553761

Hexavalent chromium damages chamomile plants by alteration of antioxidants and its uptake is prevented by calcium.

PubMed

Kováčik, Jozef; Babula, Petr; Hedbavny, Josef; Klejdus, Bořivoj

2014-05-30

Toxicity of low (3μM) and high (60 and 120μM) concentrations of hexavalent chromium/Cr(VI) in chamomile plants was studied. Fluorescence staining confirmed reduction of Cr(VI) to Cr(III). Cr was mainly accumulated in the roots with translocation factor <0.007. Notwithstanding this, both shoots and roots revealed increase in oxidative stress and depletion of glutathione, total thiols, ascorbic acid and activities of glutathione reductase and partially ascorbate peroxidase mainly at 120μM Cr. Though some protective mechanisms were detected (elevation of nitric oxide, enhancement of GPX activity and increase in phenols and lignin), this was not sufficient to counteract the oxidative damage. Consequently, soluble proteins, tissue water content and biomass production were considerably depleted. Surprising increase in some mineral nutrients in roots (Ca, Fe, Zn and Cu) was also detected. Subsequent experiment confirmed that exogenous calcium suppressed oxidative symptoms and Cr uptake but growth of chamomile seedlings was not improved. Alteration of naturally present reductants could be a reason for Cr(III) signal detected using specific fluorescence reagent: in vitro assay confirmed disappearance of ascorbic acid in equimolar mixture with dichromate (>96% at pH 4 and 7) while such response of glutathione was substantially less visible. Copyright © 2014 Elsevier B.V. All rights reserved.

[Accelerated senescence of fresh-cut Chinese water chestnut tissues in relation to hydrogen peroxide accumulation].

PubMed

Peng, Li-Tao; Jiang, Yue-Ming; Yang, Shu-Zhen; Pan, Si-Yi

2005-10-01

Accelerated senescence of fresh-cut Chinese water chestnut (CWC) tissues in relation to active oxygen species (AOS) metabolism was investigated. Fresh-cut CWC (2 mm thick) and intact CWC were stored at 4 degrees C in trays wrapped with plastic films. Changes in superoxide anion production rate, activities of superoxide dismutase (SOD), catalase (CAT) and ascorbate peroxidase (APX) were monitored, while contents of hydrogen peroxide, ascorbic acid, MDA as well as electrolyte leakage were measured. Fresh-cutting of CWC induced activities of SOD, CAT and APX to a certain extent (Fig. 2B and Fig. 3), but simultaneously stimulated superoxide anion production markedly (Fig. 2A), enhanced hydrogen peroxide accumulation and accelerated loss in ascorbic acid (Figs. 4 and 5), which resulted in increased lipid peroxidation indicated by malondialdehyde (MDA) content and electrolyte leakage (Fig. 1). Statistics analysis indicated that there was a significantly positive correlation among hydrogen peroxide accumulation, MDA content and electrolyte leakage (Table 1). Histochemical detection with 3, 3'-diaminobenzidine further demonstrated that hydrogen peroxide accumulation increased in fresh-cut CWC during storage (Fig. 5). AOS production rate and activities of SOD, CAT and APX changed little while no obvious hydrogen peroxide accumulation was observed, in intact CWC during storage.

Antioxidant Systems from Pepper (Capsicum annuum L.): Involvement in the Response to Temperature Changes in Ripe Fruits

PubMed Central

Mateos, Rosa M.; Jiménez, Ana; Román, Paloma; Romojaro, Félix; Bacarizo, Sierra; Leterrier, Marina; Gómez, Manuel; Sevilla, Francisca; del Río, Luis A.; Corpas, Francisco J.; Palma, José M.

2013-01-01

Sweet pepper is susceptible to changes in the environmental conditions, especially temperatures below 15 °C. In this work, two sets of pepper fruits (Capsicum annuum L.) which underwent distinct temperature profiles in planta were investigated. Accordingly, two harvesting times corresponding to each set were established: Harvest 1, whose fruits developed and ripened at 14.9 °C as average temperature; and Harvest 2, with average temperature of 12.4 °C. The oxidative metabolism was analyzed in all fruits. Although total ascorbate content did not vary between Harvests, a shift from the reduced to the oxidized form (dehydroascorbate), accompanied by a higher ascorbate peroxidase activity, was observed in Harvest 2 with respect to Harvest 1. Moreover, a decrease of the ascorbate-generating enzymatic system, the γ-galactono-lactone dehydrogenase, was found at Harvest 2. The activity values of the NADP-dependent dehydrogenases analyzed seem to indicate that a lower NADPH synthesis may occur in fruits which underwent lower temperature conditions. In spite of the important changes observed in the oxidative metabolism in fruits subjected to lower temperature, no oxidative stress appears to occur, as indicated by the lipid peroxidation and protein oxidation profiles. Thus, the antioxidative systems of pepper fruits seem to be involved in the response against temperature changes. PMID:23644886

Effect of Antioxidants and Carbohydrates in Callus Cultures of Taxus brevifolia: Evaluation of Browning, Callus Growth, Total Phenolics and Paclitaxel Production

PubMed Central

Yari Khosroushahi, Ahmad; Naderi-Manesh, Hossein; Toft Simonsen, Henrik

2011-01-01

Introduction To control the tissue browning phenomenon, callus growth, total phenolics and paclitaxel production, in the current investigation, we evaluated the effects of citric acid and ascorbic acid (as antioxidants) and glucose, fructose and sucrose in callus cultures of Taxus brevifolia. Methods To obtain healthy callus/cell lines of Taxus brevifolia, the effects of two antioxidants ascorbic acid (100-1000 mg/L) and citric acid (50-500 mg/L), and three carbohydrates (glucose, fructose and sucrose (5-10 g/L)) were studied evaluating activities of polyphenol oxidase (PPO) and peroxidase (PO) enzymes, callus growth/browning, total phenolics and paclitaxel production. Results These antioxidants (ascorbic acid and citric acid) failed to show significant effects on callus growth, browning intensity or paclitaxel production. However, the carbohydrates imposed significant effects on the parameters studied. High concentrations of both glucose and sucrose increased the browning intensity, thus decreased callus growth. Glucose increased paclitaxel production, but sucrose decreased it. Conclusion These results revealed that the browning phenomenon can be controlled through supplementation of the growth media with glucose, sucrose (5 g/L) and fructose (10 g/L), while increased paclitaxel production can be obtain by the optimized media supplemented with glucose (10 g/L), sucrose and fructose (5 g/L). PMID:23678406

Function of antioxidant enzymes and metabolites during maturation of pea fruits.

PubMed

Matamoros, Manuel A; Loscos, Jorge; Dietz, Karl-Josef; Aparicio-Tejo, Pedro M; Becana, Manuel

2010-01-01

In plant cells, antioxidants keep reactive oxygen species at low concentrations, avoiding oxidative damage while allowing them to play crucial functions in signal transduction. However, little is known about the role of antioxidants during fruit maturation, especially in legumes. Snap pea (Pisum sativum) plants, which have edible fruits, were grown under nodulating and non-nodulating conditions. Fruits were classified in three maturity stages and antioxidants were determined in the seeds and seedless pods. Maturation or prolonged storage of fruits at 25 degrees C led to a decline in antioxidant activities and metabolites and in gamma-glutamylcysteine synthetase protein. Notable exceptions were superoxide dismutase activity and glutathione peroxidase protein, which increased in one or both of these processes. During maturation, cytosolic peroxiredoxin decreased in seeds but increased in pods, and ascorbate oxidase activity was largely reduced in seeds. In stored fruits, ascorbate oxidase activity was nearly abolished in seeds but doubled in pods. It is concluded that symbiotic nitrogen fixation is as effective as nitrogen fertilization in maintaining the antioxidant capacity of pea fruits and that, contrary to climacteric fruits, a general decrease in antioxidants during maturation does not involve oxidative stress. Results underscore the importance of the antioxidant system in reproductive organs and point to ascorbate-glutathione metabolism and cytosolic peroxiredoxin as key players in pea fruit development.

Antioxidant capacity of parsley cells (Petroselinum crispum L.) in relation to iron-induced ferritin levels and static magnetic field.

PubMed

Rajabbeigi, Elham; Ghanati, Faezeh; Abdolmaleki, Parviz; Payez, Atefeh

2013-12-01

This study was aimed to evaluate antioxidant response of parsley cells to 21 ppm iron and static magnetic field (SMF; 30 mT). The activity of catalase (CAT) and ascorbate peroxidase (APX) and the contents of malonyldialdehyde, iron and ferritin were measured at 6 and 12 h after treatments. Exposure to SMF increased the activity of CAT in treated cells, while combination of iron and SMF treatments as well as iron supply alone decreased CAT activity, compared to that of control cells. Combination of SMF with iron treatment reduced iron content of the cells and ameliorated mal effect of iron on CAT activity. All treatments reduced APX activity; however, the content of total ascorbate increased in response to iron and SMF+iron. The results showed that among the components of antioxidant system of parsley cells, enhanced activity of CAT in SMF-treated cells and increase of ascorbate in SMF+Fe-treated ones were responsible for the maintenance of membranes integrity. Ferritin contents of SMF- and SMF+Fe-treated cells also decreased significantly 12 h after treatments, compared to those of the control cells. These results cast doubt on the proposed functions of ferritin as a putative reactive oxygen species detoxifying molecule.

L-Ascorbic acid metabolism during fruit development in an ascorbate-rich fruit crop chestnut rose (Rosa roxburghii Tratt).

PubMed

Huang, Ming; Xu, Qiang; Deng, Xiu-Xin

2014-09-01

Chestnut rose (Rosa roxburghii Tratt) is a fruit crop that contains unusually high levels of l-ascorbic acid (AsA; ∼1300 mg 100g(-1) FW). To explore the mechanisms underlying AsA metabolism, we investigated the distribution and abundance of AsA during fruit development. We also analyzed gene expression patterns, enzyme activities, and content of metabolites related to AsA biosynthesis and recycling. AsA first accumulated during late fruit development and continued to accumulate during ripening, with the highest accumulation rate near fruit maturity. The redox state of AsA in fruit was also enhanced during late fruit development, while leaf and other tissues had much lower levels of AsA and the redox state of AsA was lower. In mature fruit, AsA was mainly distributed in the cytoplasm of the mesocarp. Correlation analysis suggested that the gene expression patterns, enzyme activities, and related metabolite concentrations involved in the l-galactose pathway showed relatively high correlations with the accumulation rate of AsA. The gene expression pattern and activity of dehydroascorbate reductase (DHAR, EC 1.8.5.1) correlated strongly with AsA concentration, possibly indicating the crucial role of DHAR in the accumulation of high levels of AsA in chestnut rose fruit. Over expression of DHAR in Arabidopsis significantly increased the reduced AsA content and redox state. This was more effective than over expression of the l-galactose pathway gene GDP-d-mannose-3,5-epimerase (EC 5.1.3.18). These findings will enhance understanding of the molecular mechanisms regulating accumulation of AsA in chestnut rose. Copyright © 2014 Elsevier GmbH. All rights reserved.

Two tomato GDP-D-mannose epimerase isoforms involved in ascorbate biosynthesis play specific roles in cell wall biosynthesis and development.

PubMed

Mounet-Gilbert, Louise; Dumont, Marie; Ferrand, Carine; Bournonville, Céline; Monier, Antoine; Jorly, Joana; Lemaire-Chamley, Martine; Mori, Kentaro; Atienza, Isabelle; Hernould, Michel; Stevens, Rebecca; Lehner, Arnaud; Mollet, Jean Claude; Rothan, Christophe; Lerouge, Patrice; Baldet, Pierre

2016-08-01

GDP-D-mannose epimerase (GME, EC 5.1.3.18) converts GDP-D-mannose to GDP-L-galactose, and is considered to be a central enzyme connecting the major ascorbate biosynthesis pathway to primary cell wall metabolism in higher plants. Our previous work demonstrated that GME is crucial for both ascorbate and cell wall biosynthesis in tomato. The aim of the present study was to investigate the respective role in ascorbate and cell wall biosynthesis of the two SlGME genes present in tomato by targeting each of them through an RNAi-silencing approach. Taken individually SlGME1 and SlGME2 allowed normal ascorbate accumulation in the leaf and fruits, thus suggesting the same function regarding ascorbate. However, SlGME1 and SlGME2 were shown to play distinct roles in cell wall biosynthesis, depending on the tissue considered. The RNAi-SlGME1 plants harbored small and poorly seeded fruits resulting from alterations of pollen development and of pollination process. In contrast, the RNAi-SlGME2 plants exhibited vegetative growth delay while fruits remained unaffected. Analysis of SlGME1- and SlGME2-silenced seeds and seedlings further showed that the dimerization state of pectin rhamnogalacturonan-II (RG-II) was altered only in the RNAi-SlGME2 lines. Taken together with the preferential expression of each SlGME gene in different tomato tissues, these results suggest sub-functionalization of SlGME1 and SlGME2 and their specialization for cell wall biosynthesis in specific tomato tissues. © The Author 2016. Published by Oxford University Press on behalf of the Society for Experimental Biology.

Enhancing growth performance and systemic acquired resistance of medicinal plant Sesbania sesban (L.) Merr using arbuscular mycorrhizal fungi under salt stress

PubMed Central

Abd_Allah, Elsayed Fathi; Hashem, Abeer; Alqarawi, Abdulaziz Abdullah; Bahkali, Ali Hassan; Alwhibi, Mona S.

2015-01-01

Pot experiments were conducted to evaluate the damaging effects of salinity on Sesbania sesban plants in the presence and absence of arbuscular mycorrhizal fungi (AMF). The selected morphological, physiological and biochemical parameters of S. sesban were measured. Salinity reduced growth and chlorophyll content drastically while as AMF inoculated plants improved growth. A decrease in the number of nodules, nodule weight and nitrogenase activity was also evident due to salinity stress causing reduction in nitrogen fixation and assimilation potential. AMF inoculation increased these parameters and also ameliorated the salinity stress to some extent. Antioxidant enzymes like superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX) and glutathione reductase (GR) as well as non enzymatic antioxidants (ascorbic acid and glutathione) also exhibited great variation with salinity treatment. Salinity 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 salinity. PMID:25972748

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

PubMed Central

Racchi, Milvia Luisa

2013-01-01

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. PMID:26784469

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.

PubMed

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.

Resveratrol and its combination with α-tocopherol mediate salt adaptation in citrus seedlings.

PubMed

Kostopoulou, Zacharoula; Therios, Ioannis; Molassiotis, Athanassios

2014-05-01

Resveratrol, a phytoalexin found in red wine, has the potential to impact a variety of human diseases but its function in plants exposed to stressful conditions is still unknown. In the present study the effect of exogenous application of resveratrol (Res), α-tocopherol (α-Toc) and their combination (Res+α-Toc) in salt adaptation of citrus seedlings was investigated. It was found that Res, α-Toc or Res+α-Toc treatments reduced NaCl-derived membrane permeability (EL), lipid peroxidation (MDA) and pigments degradation, whereas companied Res and α-Toc application also reduced H2O2 accumulation in leaves and restored the reduction of photosynthesis induced by NaCl. Application of Res under salinity retained Cl- in roots while Res+α-Toc reduced the translocation of Na+ and Cl- to leaves. Carbohydrates and proline, phenols, total ascorbic acid and glutathione were remarkably affected by NaCl as well as by chemical treatments in leaves and roots of citrus. NaCl treatment increased the activity of superoxide dismutase (SOD), ascorbate peroxidase (APX), peroxidase (POD), glutathione reductase (GR), polyphenol oxidase (PPO) in leaves while SOD and POD activities were decreased in roots by this treatment. Also, Res, α-Toc or Res+α-Toc treatments displayed tissue specific activation or deactivation of the antioxidant enzymes. Overall, this work revealed a new functional role of Res in plants and provided evidence that the interplay of between Res and α-Toc is involved in salinity adaptation. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

Peroxisomal membrane ascorbate peroxidase is sorted to a membranous network that resembles a subdomain of the endoplasmic reticulum.

PubMed Central

Mullen, R T; Lisenbee, C S; Miernyk, J A; Trelease, R N

1999-01-01

The peroxisomal isoform of ascorbate peroxidase (APX) is a novel membrane isoform that functions in the regeneration of NAD(+) and protection against toxic reactive oxygen species. The intracellular localization and sorting of peroxisomal APX were examined both in vivo and in vitro. Epitope-tagged peroxisomal APX, which was expressed transiently in tobacco BY-2 cells, localized to a reticular/circular network that resembled endoplasmic reticulum (ER; 3,3'-dihexyloxacarbocyanine iodide-stained membranes) and to peroxisomes. The reticular network did not colocalize with other organelle marker proteins, including three ER reticuloplasmins. However, in vitro, peroxisomal APX inserted post-translationally into the ER but not into other purified organelle membranes (including peroxisomal membranes). Insertion into the ER depended on the presence of molecular chaperones and ATP. These results suggest that regions of the ER serve as a possible intermediate in the sorting pathway of peroxisomal APX. Insight into this hypothesis was obtained from in vivo experiments with brefeldin A (BFA), a toxin that blocks vesicle-mediated protein export from ER. A transiently expressed chloramphenicol acetyltransferase-peroxisomal APX (CAT-pAPX) fusion protein accumulated only in the reticular/circular network in BFA-treated cells; after subsequent removal of BFA from these cells, the CAT-pAPX was distributed to preexisting peroxisomes. Thus, plant peroxisomal APX, a representative enzymatic peroxisomal membrane protein, is sorted to peroxisomes through an indirect pathway involving a preperoxisomal compartment with characteristics of a distinct subdomain of the ER, possibly a peroxisomal ER subdomain. PMID:10559442

Acanthus ilicifolius L. a promising candidate for phytostabilization of zinc.

PubMed

Shackira, A M; Puthur, Jos T; Nabeesa Salim, E

2017-06-01

The potential of a halophyte species-Acanthus ilicifolius L.-to phytostabilize zinc (Zn) grown under hydroponics culture conditions was critically evaluated in this study. The propagules after treating with ZnSO 4 (4 mM) were analysed for the bioaccumulation pattern, translocation rate of Zn to the shoot, effects of Zn accumulation on organic solutes and the antioxidant defence system. It was found that most of the Zn absorbed by the plant was retained in the root (47%) and only a small portion was transported to stem (12%) and leaves (11%). This is further confirmed by the high BCF root (bioconcentration factor) value (1.99) and low TF shoot/root (translocation factor) value (0.5), which indicates the increased retention of Zn in the root itself. Moreover, treatment with Zn resulted in an increased accumulation of organic solutes (proline, free amino acids and soluble sugars) and non-enzymatic antioxidants (ascorbate, glutathione and phenol) in the leaf and root tissue. Likewise, the activity of antioxidant enzymes namely superoxide dismutase (SOD), catalase (CAT), guaiacol peroxidase (GPX) and ascorbate peroxidase (APX) recorded an enhanced activity upon exposure to Zn as compared to the control plants. Thus, the increased tolerance for Zn in A. ilicifolius may be attributed to the efficient free radical scavenging mechanisms operating under excess Zn. In addition, being a high accumulator (53.7 mg of Zn) and at the same time a poor translocator of Zn to the aerial parts of the plant, A. ilicifolius can be recommended as a potential candidate for the phytostabilization of Zn in the contaminated wetlands.

Durum wheat seedlings in saline conditions: Salt spray versus root-zone salinity

NASA Astrophysics Data System (ADS)

Spanò, Carmelina; Bottega, Stefania

2016-02-01

Salinity is an increasingly serious problem with a strong negative impact on plant productivity. Though many studies have been made on salt stress induced by high NaCl concentrations in the root-zone, few data concern the response of plants to saline aerosol, one of the main constraints in coastal areas. In order to study more in depth wheat salinity tolerance and to evaluate damage and antioxidant response induced by various modes of salt application, seedlings of Triticum turgidum ssp. durum, cv. Cappelli were treated for 2 and 7 days with salt in the root-zone (0, 50 and 200 mM NaCl) or with salt spray (400 mM NaCl + 0 or 200 mM NaCl in the root-zone). Seedlings accumulated Na+ in their leaves and therefore part of their ability to tolerate high salinity seems to be due to Na+ leaf tissue tolerance. Durum wheat, confirmed as a partially tolerant plant, shows a higher damage under airborne salinity, when both an increase in TBA-reactive material (indicative of lipid peroxidation) and a decrease in root growth were recorded. A different antioxidant response was activated, depending on the type of salt supply. Salt treatment induced a depletion of the reducing power of both ascorbate and glutathione while the highest contents of proline were detected under salt spray conditions. In the short term catalase and ascorbate peroxidase co-operated with glutathione peroxidase in the scavenging of hydrogen peroxide, in particular in salt spray-treated plants. From our data, the durum wheat cultivar Cappelli seems to be sensitive to airborne salinity.

Effects of molybdenum on water utilization, antioxidative defense system and osmotic-adjustment ability in winter wheat (Triticum aestivum) under drought stress.

PubMed

Wu, Songwei; Hu, Chengxiao; Tan, Qiling; Nie, Zhaojun; Sun, Xuecheng

2014-10-01

Molybdenum (Mo), as an essential trace element in plants, plays an essential role in abiotic stress tolerance of plants. To obtain a better understanding of drought tolerance enhanced by Mo, a hydroponic trial was conducted to investigate the effects of Mo on water utilization, antioxidant enzymes, non-enzymatic antioxidants, and osmotic-adjustment products in the Mo-efficient '97003' and Mo-inefficient '97014' under PEG simulated drought stress. Our results indicate that Mo application significantly enhanced Pn, chlorophyll, dry matter, grain yield, biomass, RWC and WUE and decreased Tr, Gs and water loss of wheat under drought stress, suggesting that Mo application improved the water utilization capacity in wheat. The activities of antioxidant enzymes such as superoxide dismutase, peroxidase, catalase, ascorbate peroxidase and the contents of non-enzymatic antioxidants content such as ascorbic acid, reduced glutathione, carotenoid were significantly increased and malonaldehyde contents were decreased by Mo application under PEG simulated drought stress, suggesting that Mo application enhanced the ability of scavenging active oxygen species. The osmotic-adjustment products such as soluble protein, proline and soluble sugar were also increased by Mo application under PEG simulated drought stress, indicating that Mo improved the osmotic adjustment ability in wheat. It is hypothesized that Mo application might improve the drought tolerance of wheat by enhancing water utilization capability and the abilities of antioxidative defense and osmotic adjustment. Similarities and differences between the Mo-efficient and Mo-inefficient cultivars wheat in response to Mo under drought stress are discussed. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

Water stress amelioration and plant growth promotion in wheat plants by osmotic stress tolerant bacteria.

PubMed

Chakraborty, U; Chakraborty, B N; Chakraborty, A P; Dey, P L

2013-05-01

Soil microorganisms with potential for alleviation of abiotic stresses in combination with plant growth promotion would be extremely useful tools in sustainable agriculture. To this end, the present study was initiated where forty-five salt tolerant bacterial isolates with ability to grow in high salt medium were obtained from the rhizosphere of Triticum aestivum and Imperata cylindrica. These bacteria were tested for plant-growth-promoting rhizobacteria traits in vitro such as phosphate solubilization, siderophore, ACC deaminase and IAA production. Of the forty-five isolates, W10 from wheat rhizosphere and IP8 from blady grass rhizosphere, which tested positive in all the tests were identified by morpholological, biochemical and 16SrDNA sequencing as Bacillus safensis and Ochrobactrum pseudogregnonense respectively and selected for in vivo studies. Both the bacteria could promote growth in six varieties of wheat tested in terms of increase in root and shoot biomass, height of plants, yield, as well as increase in chlorophyll content. Besides, the wheat plants could withstand water stress more efficiently in presence of the bacteria as indicated by delay in appearance of wilting symptoms increases in relative water content of treated water stressed plants in comparison to untreated stressed ones, and elevated antioxidant responses. Enhanced antioxidant responses were evident as elevated activities of enzymes such as catalase, peroxidase, ascorbate peroxidase, superoxide dismutase and glutathione reductase as well as increased accumulation of antioxidants such as carotenoids and ascorbate. Results clearly indicate that the ability of wheat plants to withstand water stress is enhanced by application of these bacteria which also function as plant growth promoting rhizobacteria.

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

PubMed

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.

Preillumination of lettuce seedlings with red light enhances the resistance of photosynthetic apparatus to UV-A.

PubMed

Kreslavski, Vladimir D; Lyubimov, Valery Yu; Shirshikova, Galina N; Shmarev, Alexander N; Kosobryukhov, Anatoly A; Schmitt, Franz-Josef; Friedrich, Thomas; Allakhverdiev, Suleyman I

2013-05-05

Seedlings of 10-day-old lettuce (Lactuca sativa L., cultivar Berlin) were preilluminated by low intensity red light (λmax=660 nm, 10 min, 5 μmol quanta m(-2) s(-1)) and far-red light (λmax=730 nm, 10 min, 5 μmol quanta m(-2) s(-1)) to study the effect of pre-treatment on photosynthesis, photochemical activity of photosystem II (PSII), the contents of photosynthetic and UV-A-absorbing pigments (UAPs) and H2O2, as well as total and ascorbate peroxidase activities in cotyledonary leaves of seedlings exposed to UV-A. UV radiation reduced the photosynthetic rate (Pn), the activity of PSII, and the contents of Chl a and b, carotenoids and UAPs in the leaves, but increased the content of H2O2 and the total peroxidase activity. Preillumination with red light removed these effects of UV. In turn, the illumination with red light, then far-red light removed the effect of the red light. Illumination with red light alone increased the content of UAPs, as well as peroxidase activity. It is suggested that higher resistance of the lettuce photosynthetic apparatus to UV-A radiation is associated with involvement of the active form of phytochrome B, thereby increasing peroxidase activities as well as UAPs and saving preservation of photosynthetic pigment contents due to pre-illumination with red light. Copyright © 2013 Elsevier B.V. All rights reserved.

Co-Expression of Monodehydroascorbate Reductase and Dehydroascorbate Reductase from Brassica rapa Effectively Confers Tolerance to Freezing-Induced Oxidative Stress

PubMed Central

Shin, Sun-Young; Kim, Myung-Hee; Kim, Yul-Ho; Park, Hyang-Mi; Yoon, Ho-Sung

2013-01-01

Plants are exposed to various environmental stresses and have therefore developed antioxidant enzymes and molecules to protect their cellular components against toxicity derived from reactive oxygen species (ROS). Ascorbate is a very important antioxidant molecule in plants, and monodehydroascorbate reductase (MDHAR; EC 1.6.5.4) and dehydroascorbate reductase (DHAR; EC 1.8.5.1) are essential to regeneration of ascorbate for maintenance of ROS scavenging ability. The MDHAR and DHAR genes from Brassica rapa were cloned, transgenic plants overexpressing either BrMDHAR and BrDHAR were established, and then, each transgenic plant was hybridized to examine the effects of co-expression of both genes conferring tolerance to freezing. Transgenic plants co-overexpressing BrMDHAR and BrDHAR showed activated expression of relative antioxidant enzymes, and enhanced levels of glutathione and phenolics under freezing condition. Then, these alteration caused by co-expression led to alleviated redox status and lipid peroxidation and consequently conferred improved tolerance against severe freezing stress compared to transgenic plants overexpressing single gene. The results of this study suggested that although each expression of BrMDHAR or BrDHAR was available to according tolerance to freezing, the simultaneous expression of two genes generated synergistic effects conferring improved tolerance more effectively even severe freezing. PMID:24170089

Intrinsic peroxidase-like activity of rhodium nanoparticles, and their application to the colorimetric determination of hydrogen peroxide and glucose.

PubMed

Choleva, Tatiana G; Gatselou, Vasiliki A; Tsogas, George Z; Giokas, Dimosthenis L

2017-12-05

The intrinsic peroxidase-like activity of rhodium nanoparticles (RhNPs) and their use as catalytic labels for sensitive colorimetric assays is presented. RhNPs catalyze the oxidation of the peroxidase substrate 3,3,5,5-tetramethylbenzidine (TMB) in the presence of H 2 O 2 to produce a blue reaction product with a maximum absorbance at 652 nm. Kinetic studies show catalysis to follow Michaelis-Menten kinetics and a "ping-pong" mechanism. The calculated kinetic parameters indicate high affinity of RhNPs for both the substrate TMB and H 2 O 2 . In fact, they are better than other peroxidase mimicking nanomaterials and even the natural enzyme horseradish peroxidase. On the other hand, RhNPs exhibit no reactivity towards saccharides, thiols, amino acids and ascorbic acid. Based on these findings, a sensitive and selective colorimetric method was worked out for the determination of H 2 O 2 in real samples with a linear response in the 1-100 μM concentration range. By employing glucose oxidase, the glucose assay has a linear range that covers the 5 to 125 μM glucose concentration range. The detection limits are <0.75 μM for both species. The methods were applied to the determination of H 2 O 2 in spiked pharmaceutical formulations, and of glucose in soft drinks and blood plasma. Figures of merit include (a) good accuracy (with errors of <6%), (b) high recoveries (96.5-103.7%), and (c) satisfactory reproducibility (<6.3%). Graphical abstract Rhodium nanoparticles catalyze the oxidation of 3,3,5,5-tetramethylbenzidine (TMB) in the presence of H 2 O 2 to produce a blue reaction product. The effect is exploited in photometric assays for hydrogen peroxide and glucose.

A peroxidase related to the mammalian antimicrobial protein myeloperoxidase in the Euprymna-Vibrio mutualism.

PubMed

Weis, V M; Small, A L; McFall-Ngai, M J

1996-11-26

Many animal-bacteria cooperative associations occur in highly modified host organs that create a unique environment for housing and maintaining the symbionts. It has been assumed that these specialized organs develop through a program of symbiosis-specific or -enhanced gene expression in one or both partners, but a clear example of this process has been lacking. In this study, we provide evidence for the enhanced production of an enzyme in the symbiotic organ of the squid Euprymna scolopes, which harbors a culture of the luminous bacterium Vibrio fischeri. Our data show that this enzyme has a striking biochemical similarity to mammalian myeloperoxidase (MPO; EC 1.11.17), an antimicrobial dianisidine peroxidase that occurs in neutrophils. MPO and the squid peroxidase catalyze the same reaction, have similar apparent subunit molecular masses, and a polyclonal antibody to native human MPO specifically localized a peroxidase-like protein to the bacteria-containing regions of the symbiotic organ. We also provide evidence that a previously described squid cDNA encodes the protein (LO4) that is responsible for the observed dianisidine peroxidase activity. An antibody made against a fragment of LO4 immunoprecipiated dianisidine peroxidase activity from extracts of the symbiotic organ, and reacted against these extracts and human MPO in Western blot analysis. These data suggest that related biochemical mechanisms for the control of bacterial number and growth operate in associations that are as functionally diverse as pathogenesis and mutualism, and as phylogenetically distant as molluscs and mammals.

A novel beta-glucosidase from the cell wall of maize (Zea mays L.): rapid purification and partial characterization

NASA Technical Reports Server (NTRS)

Nematollahi, W. P.; Roux, S. J.

1999-01-01

Plants have a variety of glycosidic conjugates of hormones, defense compounds, and other molecules that are hydrolyzed by beta-glucosidases (beta-D-glucoside glucohydrolases, E.C. 3.2.1.21). Workers have reported several beta-glucosidases from maize (Zea mays L.; Poaceae), but have localized them mostly by indirect means. We have purified and partly characterized a 58-Ku beta-glucosidase from maize, which we conclude from a partial sequence analysis, from kinetic data, and from its localization is not identical to any of those already reported. A monoclonal antibody, mWP 19, binds this enzyme, and localizes it in the cell walls of maize coleoptiles. An earlier report showed that mWP19 inhibits peroxidase activity in crude cell wall extracts and can immunoprecipitate peroxidase activity from these extracts, yet purified preparations of the 58 Ku protein had little or no peroxidase activity. The level of sequence similarity between beta-glucosidases and peroxidases makes it unlikely that these enzymes share epitopes in common. Contrary to a previous conclusion, these results suggest that the enzyme recognized by mWP19 is not a peroxidase, but there is a wall peroxidase closely associated with the 58 Ku beta-glucosidase in crude preparations. Other workers also have co-purified distinct proteins with beta-glucosidases. We found no significant charge in the level of immunodetectable beta-glucosidase in mesocotyls or coleoptiles that precedes the red light-induced changes in the growth rate of these tissues.

Enzyme catalysis-electrophoresis titration for multiplex enzymatic assay via moving reaction boundary chip.

PubMed

Zhong, Ran; Xie, Haiyang; Kong, Fanzhi; Zhang, Qiang; Jahan, Sharmin; Xiao, Hua; Fan, Liuyin; Cao, Chengxi

2016-09-21

In this work, we developed the concept of enzyme catalysis-electrophoresis titration (EC-ET) under ideal conditions, the theory of EC-ET for multiplex enzymatic assay (MEA), and a related method based on a moving reaction boundary (MRB) chip with a collateral channel and cell phone imaging. As a proof of principle, the model enzymes horseradish peroxidase (HRP), laccase and myeloperoxidase (MPO) were chosen for the tests of the EC-ET model. The experiments revealed that the EC-ET model could be achieved via coupling EC with ET within a MRB chip; particularly the MEA analyses of catalysis rate, maximum rate, activity, Km and Kcat could be conducted via a single run of the EC-ET chip, systemically demonstrating the validity of the EC-ET theory. Moreover, the developed method had these merits: (i) two orders of magnitude higher sensitivity than a fluorescence microplate reader, (ii) simplicity and low cost, and (iii) fairly rapid (30 min incubation, 20 s imaging) analysis, fair stability (<5.0% RSD) and accuracy, thus validating the EC-ET method. Finally, the developed EC-ET method was used for the clinical assay of MPO activity in blood samples; the values of MPO activity detected via the EC-ET chip were in agreement with those obtained by a traditional fluorescence microplate reader, indicating the applicability of the EC-ET method. The work opens a window for the development of enzymatic research, enzyme assay, immunoassay, and point-of-care testing as well as titration, one of the oldest methods of analysis, based on a simple chip.

Alpha-tocopherol-dependent salt tolerance is more related with auxin synthesis rather than enhancement antioxidant defense in soybean roots.

PubMed

Sereflioglu, Seda; Dinler, Burcu Seckin; Tasci, Eda

2017-03-01

In this paper, we describe the alleviated effects of alpha-tocopherol (α-T) on oxidative damage and its possible role as a signal transmitter in plants during salt stress. The results show that exogenously applied α-T under salt stress increased root length and weight, but reduced hydrogen peroxide (H 2 O 2 ), superoxide anion radical (O 2 . -) and malondialdehyde (MDA) content in soybean roots. The proline content was reduced by α-T treatment. Interestingly, endogenous auxin (IAA) level was significantly increased after α-T application as compared to salt stress alone. Moreover, α-T reduced significantly superoxide dismutase (SOD) enzyme and isoenzyme activity but upregulated peroxidase (POX) 2, 3 and glutathione-s-transferase (GST) 1, 3 isoenzyme expression. However, ascorbate peroxidase (APX) enzyme activity was not affected at all. Consequently, the results show that α-T serves as a signal molecule under salinity from leaves to roots by increasing remarkably endogenous IAA levels and increasing partially antioxidant activity in roots.

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

PubMed

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.

The effect of kinetin on wheat seedlings exposed to boron.

PubMed

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.

Lead phytotoxicity on wheat (Triticum aestivum L.) seed germination and seedlings growth.

PubMed

Lamhamdi, Mostafa; Bakrim, Ahmed; Aarab, Ahmed; Lafont, René; Sayah, Fouad

2011-02-01

Lead (Pb) is an environmental pollutant extremely toxic to plants and other living organisms including humans. To assess Pb phytotoxicity, experiments focusing on germination of wheat seeds were germinated in a solution containing Pb (NO(3))(2) (0.05; 0.1; 0.5; 1g/L) during 6 days. Lead accumulation in seedlings was positively correlated with the external concentrations, and negatively correlated with morphological parameters of plant growth. Lead increased lipid peroxidation, enhanced soluble protein concentrations and induced a significant accumulation of proline in roots. Esterase activity was enhanced in the presence of lead, whereas α-amylase activity was significantly inhibited. Antioxidant enzymes activities, such as, ascorbate peroxidase, peroxidase, superoxide dismutase, catalase and glutathione S-transferase were generally significantly increased in the presence of lead in a dose-dependent manner. The present results thus provide a model system to screen for natural compounds able to counteract the deleterious effects of lead. Copyright © 2010 Académie des sciences. Published by Elsevier SAS. All rights reserved.

Extremely high boron tolerance in Puccinellia distans (Jacq.) Parl. related to root boron exclusion and a well-regulated antioxidant system.

PubMed

Hamurcu, Mehmet; Hakki, Erdogan E; Demiral Sert, Tijen; Özdemir, Canan; Minareci, Ersin; Avsaroglu, Zuhal Z; Gezgin, Sait; Ali Kayis, Seyit; Bell, Richard W

Recent studies indicate an extremely high level of tolerance to boron (B) toxicity in Puccinellia distans (Jacq.) Parl. but the mechanistic basis is not known. Puccinellia distans was exposed to B concentrations of up to 1000 mg B L-1 and root B uptake, growth parameters, B and N contents, H2O2 accumulation and ·OH-scavenging activity were measured. Antioxidant enzyme activities including superoxide dismutase (SOD), ascorbate peroxidase, catalase, peroxidase and glutathione reductase, and lipid peroxidation products were determined. B appears to be actively excluded from roots. Excess B supply caused structural deformations in roots and leaves, H2O2 accumulation and simultaneous up-regulation of the antioxidative system, which prevented lipid peroxidation even at the highest B concentrations. Thus, P. distans has an efficient root B-exclusion capability and, in addition, B tolerance in shoots is achieved by a well-regulated antioxidant defense system.

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

PubMed

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.

Alleviation of Salt Stress in Pepper (Capsicum annum L.) Plants by Plant Growth-Promoting Rhizobacteria.

PubMed

Hahm, Mi-Seon; Son, Jin-Soo; Hwang, Ye-Ji; Kwon, Duk-Kee; Ghim, Sa-Youl

2017-10-28

In the present study, we demonstrate that the growth of salt-stressed pepper plants is improved by inoculation with plant growth-promoting rhizobacteria (PGPR). Three PGPR strains ( Microbacterium oleivorans KNUC7074, Brevibacterium iodinum KNUC7183, and Rhizobium massiliae KNUC7586) were isolated from the rhizosphere of pepper plants growing in saline soil, and pepper plants inoculated with these PGPR strains exhibited significantly greater plant height, fresh weight, dry weight, and total chlorophyll content than non-inoculated plants. In addition, salt-stressed pepper plants that were inoculated with B. iodinum KNUC7183 and R. massiliae KNUC7586 possessed significantly different total soluble sugar and proline contents from non-inoculated controls, and the activity of several antioxidant enzymes (ascorbate peroxidase, guaiacol peroxidase, and catalase) was also elevated in PGPR-treated plants under salt stress. Overall, these results suggest that the inoculation of pepper plants with M. oleivorans KNUC7074, B. iodinum KNUC7183, and R. massiliae KNUC7586 can alleviate the harmful effects of salt stress on plant growth.

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

PubMed

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.

Melatonin attenuates postharvest physiological deterioration of cassava storage roots.

PubMed

Ma, Qiuxiang; Zhang, Ting; Zhang, Peng; Wang, Zhen-Yu

2016-05-01

Melatonin reportedly increases abiotic and biotic stress tolerance in plants, but information on its in vivo effects during postharvest physiological deterioration (PPD) in cassava is limited. In this study, we investigated the effect of melatonin in regulating cassava PPD. Treatment with 500 mg/L melatonin significantly delayed cassava PPD and reduced the accumulation of hydrogen peroxide (H2O2) while increasing the activity of superoxide dismutase (SOD), catalase (CAT), and glutathione reductase (GR), but not ascorbate peroxidase (APX). Transcript analysis further showed that expression of copper/zinc SOD (MeCu/ZnSOD), MeCAT1, glutathione peroxidase (MeGPX), peroxidase 3 (MePX3), and glutathione S-transferases (MeGST) was higher in cassava roots sliced treated with 500 mg/L melatonin than in those not exposed to exogenous melatonin. These data demonstrate that melatonin delays cassava PPD by directly or indirectly maintaining homoeostasis of cellular reactive oxygen species (ROS). We also found that accumulation of endogenous melatonin and the transcript levels of melatonin biosynthesis genes changed dynamically during the PPD process. This finding suggested that endogenous melatonin acts as a signal modulator for maintaining cassava PPD progression and that manipulation of melatonin biosynthesis genes through genetic engineering might prevent cassava root deterioration. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Effects of different depth of grain colour on antioxidant capacity during water imbibition in wheat (Triticum aestivum L.).

PubMed

Shin, Oon Ha; Kim, Dae Yeon; Seo, Yong Weon

2017-07-01

The importance of the effect of phytochemical accumulation in wheat grain on grain physiology has been recognised. In this study, we tracked phytochemical concentration in the seed coat of purple wheat during the water-imbibition phase and also hypothesised that the speed of germination was only relevant to its initial phytochemical concentration. The results indicate that the speed of germination was significantly reduced in the darker grain groups within the purple wheat. Total phenol content was slightly increased in all groups compared to their initial state, but the levels of other phytochemicals varied among groups. It is revealed that anthocyanin was significantly degraded during the water imbibition stage. Also, the activities of peroxidase, ascorbate peroxidase, catalase, glutathione S-transferase, glutathione reductase, and glutathione peroxidase in each grain colour group did not correlated with germination speed. Overall antioxidant activity was reduced as imbibition progressed in each group. Generally, darker grain groups showed higher total antioxidant activities than did lighter grain groups. These findings suggested that the reduced activity of reactive oxygen species, as controlled by internal antioxidant enzymes and phytochemicals, related with germination speed during the water imbibition stage in grains with greater depth of purple colouring. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

Purification and characterization of peroxidase from cauliflower (Brassica oleracea L. var. botrytis) buds.

PubMed

Köksal, Ekrem; Gülçin, Ilhami

2008-01-01

Peroxidases (EC 1.11.1.7; donor: hydrogen peroxide oxidoreductase) are part of a large group of enzymes. In this study, peroxidase, a primer antioxidant enzyme, was purified with 19.3 fold and 0.2% efficiency from cauliflower (Brassica oleracea L.) by ammonium sulphate precipitation, dialysis, CM-Sephadex ion-exchange chromatography and Sephadex G-25 purification steps. The substrate specificity of peroxidase was investigated using 2,2'-azino-bis(3-ethylbenz-thiazoline-6-sulphonic acid) (ABTS), 2-methoxyphenol (guaiacol), 1,2-dihydroxybenzene (catechol), 1,2,3-trihyidroxybenzene (pyrogallol) and 4-methylcatechol. Also, optimum pH, optimum temperature, optimum ionic strength, stable pH, stable temperature, thermal inactivation conditions were determined for guaiacol/H(2)O(2), pyrogallol/H(2)O(2), ABTS/H(2)O(2), catechol/H(2)O(2) and 4-methyl catechol/H(2)O(2) substrate patterns. The molecular weight (M(w)) of this enzyme was found to be 44 kDa by gel filtration chromatography method. Native polyacrylamide gel electrophoresis (PAGE) was performed for isoenzyme determination and a single band was observed. K(m) and V(max) values were calculated from Lineweaver-Burk graph for each substrate patterns.

Temporal mismatch between induction of superoxide dismutase and ascorbate peroxidase correlates with high H2O2 concentration in seawater from clofibrate-treated red algae Kappaphycus alvarezii.

PubMed

Barros, Marcelo P; Granbom, Malena; Colepicolo, Pio; Pedersén, Marianne

2003-12-01

Algal cells have developed different strategies to cope with the common environmentally promoted generation of H(2)O(2), which include induction of catalase (CAT) and ascorbate peroxidase (APX), massive H(2)O(2) release in seawater, and synthesis of volatile halocarbons by specific peroxidases. The antioxidant adaptability of the economically important carrageenophyte Kappaphycus alvarezii (Doty) Doty (Gigartinales: Rhodophyta) was tested here against exposure to clofibrate (CFB), a known promoter of peroxisomal beta-oxidation in mammals and plants. Possibly as a consequence of CFB-induced H2O2 peroxisomal production, the maximum concentration of H(2)O(2) in the seawater of red algae cultures was found to occur (120+/-17 min) after the addition of CFB, which was followed by a significant decrease in the photosynthetic activity of PSII after 24 h. Interestingly, 4 h after the addition of CFB, the total SOD activity was about 2.5-fold higher than in the control, whereas no significant changes were observed in lipoperoxidation levels (TBARS) or in CAT and APX activities. The two H(2)O(2)-scavenging enzymes were only induced later (after 72 h), whereupon CAT showed a dose-dependent response with increasing concentrations of CFB. A more pronounced increase of TBARS concentration than in the controls was evidenced when a 50 microM Fe(2+/3+) solution (3:2 ratio) was added to CFB-treated cultures, suggesting that the combination of exacerbated H(2)O(2) levels in the seawater-in this work, caused by CFB exposure-and Fenton-reaction catalyst (ferric/ferrous ions), imposes harsh oxidative conditions on algal cultures. The bulk of data suggests that K. alvarezii possesses little ability to promptly induce CAT and APX compared to the immediately responsive antioxidant enzyme SOD and, to avoid harmful accumulation of H(2)O(2), the red alga presumably releases H(2)O(2) into the surrounding medium as an alternative mechanism.

Purification and partial characterization of peroxidase from human term placenta of non-smokers: metabolism of benzo(a)pyrene-7, 8-dihydrodiol.

PubMed

Madhavan, N D; Naidu, K A

2000-01-01

Peroxidase (Donor: H(2)O(2)oxidoreductase EC 1.11.1.7) from human term placentae of non-smokers was purified to homogeneity by a combination of NH(4)Cl extraction, affinity chromatography, (NH(4))(2)SO(4)precipitation, ion-exchange and gel filtration chromatography. The homogeneity of purified human placental peroxidase (HTPP) was confirmed by gel filtration, reverse phase high performance liquid chromatography (HPLC) and SDS-PAGE. Peroxidase was found to be a membrane bound enzyme. A high concentration of NH(4)Cl (1.2 m) was needed to extract and solublize the enzyme. Removal of the salt resulted in irreversible precipitation of the enzyme. The protein exhibited a molecular mass of 126 000 kDa according to gel filtration and approximately 60 000 kDa by SDS-PAGE, indicating that the peroxidase is a homodimer. The purified peroxidase showed an optimum pH range of 7 to 8.5 and the K(m)for H(2)O(2)and guaiacol were found to be 0.08 m m and 10.0 m m, respectively. The purified peroxidase oxidized several substrates, namely potassium iodide, tetramethyl benzidine, guaiacol, ortho dianisidne and tyrosine. The enzyme was resistant to thermal denaturation up to 70 degrees C and also to chaotropic agents, guanidinium chloride and urea. Spectral properties indicated the presence of Soret band at 433 which shifted to 451 nm on complexation with cyanide. The circular dichroism studies showed that HTPP has a predominantly helical secondary structure. The enzyme showed similarities to the myeloperoxidase with regard to spectral and catalytical properties but differed significantly in amino acid composition, the R(z)value and molecular mass. Purified HTPP differed from eosinophil peroxidase in all physico-chemical properties indicating that it is not of eosinophil origin, but may represent a distinct, constitutive peroxidase in human placenta. Further, purified peroxidase catalyzed oxidation of benzo(a)pyrene-7, 8-dihydrodiol in presence of tyrosine and hydrogen peroxide to BP-tetrols, the hydrolytic products of BP-diol-epoxides, demonstrating the ability of peroxidase in bioactivation of benzo(a)pyrene in human placenta. Copyright 2000 Harcourt Publishers Ltd.

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

PubMed

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.

Determining Glutathione Levels in Plants.

PubMed

Sahoo, Smita; Awasthi, Jay Prakash; Sunkar, Ramanjulu; Panda, Sanjib Kumar

2017-01-01

Upon exposure to abiotic stresses, plants tend to accumulate excessive amounts of reactive oxygen species (ROS) that inturn react with cellular lipids, proteins, and DNA. Therefore, decreasing ROS accumulation is indispensible to survive under stress, which is accomplished by inducing enzymatic and nonenzymatic antioxidant defense pathways. Glutathione, particularly reduced glutathione (GSH), represents a principal anitioxidant that could decrease ROS through scavenging them directly or indirectly through ascorbate-glutathione cycle or GSH peroxidases. Glutathione content can be determined using HPLC or spectrophotometric assays. In this chapter, we provided detailed assays to determine total, reduced, and oxidized gluathione using spectrophotometric method.

Comparative analysis of peroxidase profiles in Chinese kale (Brassica alboglabra L.): evaluation of leaf growth related isozymes.

PubMed

Tang, Lei; Wang, Chenchen; Huang, Jiabao; Zhang, Jianhua; Mao, Zhonggui; Wang, Haiou

2013-01-15

Plant peroxidases (EC 1.11.1.7) with different isoforms catalyze various reactions in plant growth and development. However, it is difficult to elucidate the function of each isozyme in one plant. Here, we compared profiles of entire isozyme in young seedling and mature leaves of Chinese kale (Brassica alboglabra L.) on zymogram and ion exchange chromatography in order to investigate leaf growth related peroxidase isozymes. The results showed that four isozymes were constitutively expressed in kale leaves, whereas other two isozymes were induced in the mature leaves. The Mono Q ion exchange chromatography separated the six isozymes into two major groups due to the difference in their isoelectric points. The results suggested that although there were several isozymes in the leaves of Chinese kale, one isozyme functioned mainly through the leaf development. Two anionic isozymes with molecular weights lower than 32 kDa were considered mature related. Copyright © 2012 Elsevier Ltd. All rights reserved.

Biochemical Characterization and Antimicrobial and Antifungal Activity of Two Endemic Varieties of Garlic (Allium sativum L.) of the Campania Region, Southern Italy.

PubMed

Fratianni, Florinda; Riccardi, Riccardo; Spigno, Patrizia; Ombra, Maria Neve; Cozzolino, Autilia; Tremonte, Patrizio; Coppola, Raffaele; Nazzaro, Filomena

2016-07-01

Extracts of the bulbs of the two endemic varieties "Rosato" and "Caposele" of Allium sativum of the Campania region, Southern Italy, were analyzed. The phenolic content, ascorbic acid, allicin content, and in vitro antimicrobial and antifungal activity were determined. Ultra performance liquid chromatography with diode array detector performed polyphenol profile. The polyphenolic extracts showed antioxidant activity (EC50) lower than 120 mg. The amount of ascorbic acid and allicin in the two extracts was similar. Polyphenol extract exhibited antimicrobial activity against Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, and (only by the extract of Rosato) against Bacillus cereus. The extract of Caposele was more effective in inhibiting the growth of Aspergillus versicolor and Penicillum citrinum. On the other hand, the extract of Rosato was effective against Penicillium expansum.

Peroxidase-mediated dealkylation of tamoxifen, detected by electrospray ionization-mass spectrometry, and activation to form DNA adducts.

PubMed

Gaikwad, Nilesh W; Bodell, William J

2012-01-15

Tamoxifen (TAM) is extensively used for the treatment and prevention of breast cancer. Associated with TAM treatment is a two- to eightfold increase in risk of endometrial cancer. To understand the mechanisms associated with this increased risk several pathways for TAM metabolism and DNA adduct formation have been studied. The purpose of this study was to investigate the role of peroxidase enzymes in the metabolism of TAM and its activation to form DNA adducts. Using advanced tandem mass spectrometry we have investigated the peroxidase-mediated metabolism of TAM. Incubation of TAM with horseradish peroxidase (HRP) and H(2)O(2) produced multiple metabolites. Electrospray ionization-MS/MS analysis of the metabolites demonstrated a peak at 301.3m/z with daughter ions at 183.0, 166.9, 128.9, and 120.9m/z, which identified the metabolite as metabolite E (ME). The levels of ME were significantly inhibited by the addition of ascorbic acid to the incubation mixture. Co-incubation of either TAM or ME and DNA with HRP and H(2)O(2) produced three DNA adducts with a RAL of 1.97±0.01×10(-7) and 8.45±2.7×10(-7). Oxidation of ME with MnO(2) produced metabolite E quinone methide (MEQM). Furthermore, incubation of either TAM or ME with HRP and H(2)O(2) resulted in formation of MEQM. Reaction of calf thymus DNA with MEQM produced three DNA adducts with a RAL of 9.8±1.0×10(-7). Rechromatography analyses indicated that DNA adducts 1, 2, and 3 formed in the HRP activation of either TAM or ME were the same as those formed by the chemical reaction of DNA with MEQM. The results of these studies demonstrate that peroxidase enzymes can both metabolize TAM to form the primary metabolite ME and activate ME to a quinone methide intermediate, which reacts with DNA to form adducts. It is possible that peroxidase enzymes or peroxidase-like activity in endometrium could contribute to the formation of DNA damage and genotoxic effects in endometrium after TAM administration. Published by Elsevier Inc.

The catalytic mechanism of dye-decolorizing peroxidase DyP may require the swinging movement of an aspartic acid residue.

PubMed

Yoshida, Toru; Tsuge, Hideaki; Konno, Hiroki; Hisabori, Toru; Sugano, Yasushi

2011-07-01

The dye-decolorizing peroxidase (DyP)-type peroxidase family is a unique heme peroxidase family. The primary and tertiary structures of this family are obviously different from those of other heme peroxidases. However, the details of the structure-function relationships of this family remain poorly understood. We show four high-resolution structures of DyP (EC1.11.1.19), which is representative of this family: the native DyP (1.40 Å), the D171N mutant DyP (1.42 Å), the native DyP complexed with cyanide (1.45 Å), and the D171N mutant DyP associated with cyanide (1.40 Å). These structures contain four amino acids forming the binding pocket for hydrogen peroxide, and they are remarkably conserved in this family. Moreover, these structures show that OD2 of Asp171 accepts a proton from hydrogen peroxide in compound I formation, and that OD2 can swing to the appropriate position in response to the ligand for heme iron. On the basis of these results, we propose a swing mechanism in compound I formation. When DyP reacts with hydrogen peroxide, OD2 swings towards an optimal position to accept the proton from hydrogen peroxide bound to the heme iron. © 2011 The Authors Journal compilation © 2011 FEBS.

Rapid enzymatic analysis of plasma for tyrosine.

PubMed

Shimizu, H; Taniguchi, K; Sugiyama, M; Kanno, T

1990-01-01

In this rapid, simple, and convenient enzymatic method for measurement of tyrosine in plasma, tyrosine is converted to tyramine by action of tyrosine decarboxylase (EC 4.1.1.25) and the tyramine produced is oxidized to p-hydroxybenzyl aldehyde and hydrogen peroxide by action of tyramine oxidase (EC 1.4.3.9). The hydrogen peroxide is reacted with 4-aminoantipyrine and N-ethyl-N-(2-hydroxy-3-sulfopropyl)-m-toluidine in the presence of peroxidase (EC 1.11.1.7) to obtain quinoneimine dye, the absorbance of which is measured at 570 nm. Thus tyrosine is measured in the visible range. The CV was 4.6% or less, and the measurement was unaffected by other amino acids, except for phenylalanine. The values obtained (y) correlated well with those obtained with an amino acid analyzer (x): y = 0.902x + 3.92 mumol/L (Syx = 12.3; r = 0.985; n = 54).

Automated enzymatic measurement of lecithin, sphingomyelin, and phosphatidylglycerol in amniotic fluid.

PubMed

Bradley, C A; Salhany, K E; Entman, S S; Aleshire, S L; Parl, F F

1987-01-01

We describe methods for automated enzymatic measurement of lecithin, sphingomyelin, and phosphatidylglycerol in amniotic fluid. Phospholipase C (EC 3.1.4.3) and sphingomyelin phosphodiesterase (EC 3.1.4.12) are reacted with lecithin and sphingomyelin, respectively, to liberate phosphocholine. Phosphocholine is then reacted with alkaline phosphatase, choline oxidase, peroxidase, and 4-aminoantipyrine to form a colored complex, for which the absorbance at 500 nm is measured with a centrifugal analyzer. Phosphatidylglycerol is hydrolyzed by phospholipase D (EC 3.1.4.4) to form glycerol, which is subsequently reacted with ATP and NAD+ in the presence of glycerol kinase and glycerol-3-phosphate dehydrogenase to yield NADH. The absorbance of the NADH formed is measured at 340 nm. These methods provide a simple, rapid, and accurate alternative to thin-layer chromatography for determination of phospholipids in amniotic fluid for assessment of fetal lung maturity.

Differential effect of UV-B radiation on growth, oxidative stress and ascorbate-glutathione cycle in two cyanobacteria under copper toxicity.

PubMed

Singh, Vijay Pratap; Srivastava, Prabhat Kumar; Prasad, Sheo Mohan

2012-12-01

Effects of low (UV-B(L); 0.1 μmol m(-2) s(-1)) and high (UV-B(H); 1.0 μmol m(-2) s(-1)) fluence rates of UV-B radiation on growth, oxidative stress and ascorbate-glutathione cycle (AsA-GSH cycle) were investigated in two cyanobacteria viz. Phormidium foveolarum and Nostoc muscorum under copper (2 and 5 μM) toxicity after 24 and 72 h of experiments. Cu at 2 and 5 μM and UV-B(H) irradiation decreased growth in both the organisms and the effect was more pronounced in N. muscorum. Superoxide radical (SOR) and hydrogen peroxide (H(2)O(2)) productions were significantly enhanced by Cu and UV-B(H) which was accompanied by accelerated lipid peroxidation (malondialdehyde; MDA) and protein oxidation (reactive carbonyl groups; RCG). The components of AsA-GSH cycle, i.e. ascorbate peroxidase (APX), glutathione reductase (GR), monodehydroascobate reductase (MDHAR) and dehydroascorbate reductase (DHAR) activities as well as total ascorbate and glutathione contents and their reduced/oxidized ratios were decreased considerably by Cu and UV-B(H). Further, combined treatments of Cu and UV-B(H) exacerbated damaging effects in both the cyanobacteria. Unlike UV-B(H), UV-B(L) irradiation rather than damaging cyanobacteria caused alleviation in Cu-induced toxicity by down-regulating the levels of SOR, H(2)O(2), MDA and RCG due to enhanced activity of APX, GR, MDHAR and DHAR, and contents of ascorbate and glutathione. Results revealed that UV-B radiation at low fluence rate (UV-B(L)) stimulated protective responses in both the organisms under Cu toxicity while UV-B(H) irradiation caused damage alone as well as together with Cu, and the components of AsA-GSH cycle play significant role in these responses. Copyright © 2012 Elsevier Masson SAS. All rights reserved.

CO(2)-induced total phenolics in suspension cultures of Panax ginseng C. A. Mayer roots: role of antioxidants and enzymes.

PubMed

Ali, Mohammad Babar; Hahn, Eun Joo; Paek, Kee-Yoeup

2005-05-01

The effects of different concentrations of CO(2) (1%, 2.5% and 5%) on the antioxidant capacity, total phenols, flavonoids, protein content and phenol biosynthetic enzymes in roots of Panax ginseng were studied in bioreactor (working volume 4 l) after 15, 30 and 45 days. CO(2) induced accumulation of total phenolics in a concentration and duration dependent manner. Total phenols, flavonoids and 1,1-diphenyl-2-picrylhydrazyl (DPPH) activity increased 60%, 30% and 20% at 2.5% CO(2) after 45 days compared to control in P. ginseng roots which indicated that phenolics compounds played an important role in protecting the plants from CO(2). Hypothesizing that increasing the phenolic compounds in roots of P. ginseng may increase its nutritional functionality; we investigated whether pentose phosphate pathway (PPP), shikimate/phenylpropanoid pathway enzymes have a role in phenolics mobilization in P. ginseng roots. Fresh weight (FW), dry weight (DW) and growth ratio was increased at 1% and 2.5% CO(2) only after 45 days, however, unaffected after 15 and 30 days. Results also indicated that high CO(2) progressively stimulated the activities of glucose 6 phosphate dehydrogenase (G6PDH, E.C. 1.1.1.49), shikimate dehydrogenase (SKDH, E.C. 1.1.1.25), phenylalanine ammonia lyase (PAL, E.C. 4.3.1.5), cinnamyl alcohol dehydrogenase (CAD, E.C. 1.1.1.195), caffeic acid (CA) peroxidase and chlorogenic acid (CGA) peroxidase after 15, 30 and 45 days. Increased CO(2) levels resulted in increases in accumulation of total protein (45%), non-protein thiol (NP-SH) (30%) and cysteine contents (52%) after 45 days compared to control and increased activities of beta-glucosidase (GS, E.C. 3.2.1.21) and polyphenol oxidase (PPO, E.C. 1.10.3.2) in P. ginseng roots indicated that they played an important role in protecting the plants from CO(2). These results strongly suggest that high concentration of CO(2) delivered to ginseng root suspension cultures induced the accumulation of total phenolics possessing high antioxidant properties probably useful for human health. Therefore, roots of P. ginseng are considered as a good source of phenolics compounds with high antioxidants capacity and can be produced on a large scale.

Transcriptional regulation of heat shock proteins and ascorbate peroxidase by CtHsfA2b from African bermudagrass conferring heat tolerance in Arabidopsis

PubMed Central

Wang, Xiuyun; Huang, Wanlu; Yang, Zhimin; Liu, Jun; Huang, Bingru

2016-01-01

Heat stress transcription factor A2s (HsfA2s) are key regulators in plant response to high temperature. Our objectives were to isolate an HsfA2 gene (CtHsfA2b) from a warm-season grass species, African bermudagrass (Cynodon transvaalensis Burtt-Davy), and to determine the physiological functions and transcriptional regulation of HsfA2 for improving heat tolerance. Gene expression analysis revealed that CtHsfA2b was heat-inducible and exhibited rapid response to increasing temperature. Ectopic expression of CtHsfA2b improved heat tolerance in Arabidopsis and restored heat-sensitive defects of Arabidopsis hsfa2 mutant, which was demonstrated by higher survival rate and photosynthetic parameters, and lower electrolyte leakage in transgenic plants compared to the WT or hsfa2 mutant. CtHsfA2b transgenic plants showed elevated transcriptional regulation of several downstream genes, including those encoding ascorbate peroxidase (AtApx2) and heat shock proteins [AtHsp18.1-CI, AtHsp22.0-ER, AtHsp25.3-P and AtHsp26.5-P(r), AtHsp70b and AtHsp101-3]. CtHsfA2b was found to bind to the heat shock element (HSE) on the promoter of AtApx2 and enhanced transcriptional activity of AtApx2. These results suggested that CtHsfA2b could play positive roles in heat protection by up-regulating antioxidant defense and chaperoning mechanisms. CtHsfA2b has the potential to be used as a candidate gene to genetically modify cool-season species for improving heat tolerance. PMID:27320381

Nitric oxide activates superoxide dismutase and ascorbate peroxidase to repress the cell death induced by wounding.

PubMed

Lin, Chih-Ching; Jih, Pei-Ju; Lin, Hsin-Hung; Lin, Jeng-Shane; Chang, Ling-Lan; Shen, Yu-Hsing; Jeng, Shih-Tong

2011-10-01

Wounding caused by rain, wind, and pathogen may lead plants to onset defense response. Previous studies indicated that mechanical wounding stimulates plants to generate nitric oxide (NO) and hydrogen peroxide (H(2)O(2)). In this study, the functions of NO and H(2)O(2) after wounding in sweet potato (Ipomoea batatas cv. Tainung 57) was further analyzed. Mechanical wounding damaged cells and resulted in necrosis, but the presence of NO donors or NO scavenger might reduce or enhance the cell death caused by wounding, respectively. The amount of H(2)O(2) induced by wounding was also decreased or increased when plants were incubated with NO donors or NO scavenger, individually. These results indicate that NO may regulate H(2)O(2) generation to affect cell death. NO-induced proteins isolated from two-dimensional electrophoresis were identified to be Copper/Zinc superoxide dismutases (CuZnSODs). The activities of CuZnSODs and ascorbate peroxidase (APX) could be enhanced by NO. In addition, the expression of CuZnSOD and APX was induced by wounding via NO, and their expression was further stimulated by NO through the generation of cGMP. The influx of calcium ions and the activity of NADPH oxidase were also involved in the NO signal transduction pathway inducing APX expression. Collectively, the generation of H(2)O(2) in wounded plants might trigger cell death. Meanwhile, the production of NO induced by wounding stimulated signal transducers including cGMP, calcium ions, and H(2)O(2) to activate CuZnSOD and APX, which further decreased H(2)O(2) level and reduced the cell death caused by wounding.

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

PubMed

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.

Enhanced seed production under prolonged heat stress conditions in Arabidopsis thaliana plants deficient in cytosolic ascorbate peroxidase 2

PubMed Central

Mittler, Ron

2013-01-01

Reactive oxygen species play a key role in the response of plants to abiotic stress conditions. Their level is controlled in Arabidopsis thaliana by a large network of genes that includes the H2O2-scavenging enzymes cytosolic ascorbate peroxidase (APX) 1 and 2. Although the function of APX1 has been established under different growth conditions, genetic evidence for APX2 function, as well as for the mode of cooperation between APX1 and APX2, is very limited. This study characterized the response of Arabidopsis mutants deficient in APX1, APX2, and APX1/APX2 to heat, salinity, light, and oxidative stresses. The findings reveal that deficiency in APX2 resulted in a decreased tolerance to light stress, as well as an enhanced tolerance to salinity and oxidative stresses. Interestingly, plants lacking APX2 were more sensitive to heat stress at the seedling stage, but more tolerant to heat stress at the reproductive stage. Cooperation between APX1 and APX2 was evident during oxidative stress, but not during light, salinity, or heat stress. The findings demonstrate a role for APX2 in the response of plants to light, heat, salinity, and oxidative stresses. The finding that plants lacking APX2 produced more seeds under prolonged heat stress conditions suggests that redundant mechanisms activated in APX2-deficient plants during heat stress play a key role in the protection of reproductive tissues from heat-related damage. This finding is very important because heat-associated damage to reproductive tissues in different crops is a major cause for yield loss in agriculture production worldwide. PMID:23183257

The knockdown of chloroplastic ascorbate peroxidases reveals its regulatory role in the photosynthesis and protection under photo-oxidative stress in rice.

PubMed

Caverzan, Andréia; Bonifacio, Aurenivia; Carvalho, Fabricio E L; Andrade, Claudia M B; Passaia, Gisele; Schünemann, Mariana; Maraschin, Felipe Dos Santos; Martins, Marcio O; Teixeira, Felipe K; Rauber, Rafael; Margis, Rogério; Silveira, Joaquim Albenisio Gomes; Margis-Pinheiro, Márcia

2014-01-01

The inactivation of the chloroplast ascorbate peroxidases (chlAPXs) has been thought to limit the efficiency of the water-water cycle and photo-oxidative protection under stress conditions. In this study, we have generated double knockdown rice (Oryza sativa L.) plants in both OsAPX7 (sAPX) and OsAPX8 (tAPX) genes, which encode chloroplastic APXs (chlAPXs). By employing an integrated approach involving gene expression, proteomics, biochemical and physiological analyses of photosynthesis, we have assessed the role of chlAPXs in the regulation of the protection of the photosystem II (PSII) activity and CO2 assimilation in rice plants exposed to high light (HL) and methyl violagen (MV). The chlAPX knockdown plants were affected more severely than the non-transformed (NT) plants in the activity and structure of PSII and CO2 assimilation in the presence of MV. Although MV induced significant increases in pigment content in the knockdown plants, the increases were apparently not sufficient for protection. Treatment with HL also caused generalized damage in PSII in both types of plants. The knockdown and NT plants exhibited differences in photosynthetic parameters related to efficiency of utilization of light and CO2. The knockdown plants overexpressed other antioxidant enzymes in response to the stresses and increased the GPX activity in the chloroplast-enriched fraction. Our data suggest that a partial deficiency of chlAPX expression modulate the PSII activity and integrity, reflecting the overall photosynthesis when rice plants are subjected to acute oxidative stress. However, under normal growth conditions, the knockdown plants exhibit normal phenotype, biochemical and physiological performance. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

In Vitro Evaluation of Antileishmanial Activity of Computationally Screened Compounds against Ascorbate Peroxidase To Combat Amphotericin B Drug Resistance

PubMed Central

Mansuri, Rani; Kumar, Ashish; Rana, Sindhuprava; Panthi, Bhavana; Ansari, M. Yousuf; Das, Sushmita; Dikhit, Manas Ranjan

2017-01-01

ABSTRACT In visceral leishmaniasis (VL), the host macrophages generate oxidative stress to destroy the pathogen, while Leishmania combats the harmful effect of radicals by redox homeostasis through its unique trypanothione cascade. Leishmania donovani ascorbate peroxidase (LdAPx) is a redox enzyme that regulates the trypanothione cascade and detoxifies the effect of H2O2. The absence of an LdAPx homologue in humans makes it an excellent drug target. In this study, the homology model of LdAPx was built, including heme, and diverse compounds were prefiltered (PAINS, ADMET, and Lipinski's rule of five) and thereafter screened against the LdAPx model. Compounds having good affinity in terms of the Glide XP (extra precision) score were clustered to select diverse compounds for experimental validation. A total of 26 cluster representatives were procured and tested on promastigote culture, yielding 12 compounds with good antileishmanial activity. Out of them, six compounds were safer on the BALB/c peritoneal macrophages and were also effective against disease-causing intracellular amastigotes. Three out of six compounds inhibited recombinant LdAPx in a noncompetitive manner and also demonstrated partial reversion of the resistance property in an amphotericin B (AmB)-resistant strain, which may be due to an increased level of reactive oxygen species (ROS) and decrease of glutathione (GSH) content. However, inhibition of LdAPx in resistant parasites enhanced annexin V staining and activation of metacaspase-like protease activity, which may help in DNA fragmentation and apoptosis-like cell death. Thus, the present study will help in the search for specific hits and templates of potential therapeutic interest and therefore may facilitate the development of new drugs for combination therapy against VL. PMID:28461317

Peroxidative Metabolism of β2-Agonists Salbutamol and Fenoterol and Their Analogs

PubMed Central

Reszka, Krzysztof J.; McGraw, Dennis W.; Britigan, Bradley E.

2009-01-01

Phenolic β2-adrenoreceptor agonists salbutamol, fenoterol and terbutaline relax smooth muscle cells that relieve acute airway bronchospasm associated with asthma. Why their use sometimes fails to relieve bronchospasm, and why the drugs appear to be less effective in patients with severe asthma exacerbations, remains unclear. We show that in the presence of hydrogen peroxide, both myeloperoxidase, secreted by activated neutrophils present in inflamed airways, and lactoperoxidase, which is naturally present in the respiratory system, catalyze oxidation of these β2-agonists. Azide, cyanide, thiocyanate, ascorbate, glutathione, and methimazole inhibited this process, while methionine was without effect. Inhibition by ascorbate and glutathione was associated with their oxidation to corresponding radical species by the agonists’-derived phenoxyl radicals. Using electron paramagnetic resonance (EPR), we detected free radical metabolites from β2-agonists by spin trapping with 2-methyl-2-nitrosopropane (MNP). Formation of these radicals was inhibited by pharmacologically-relevant concentrations of methimazole and dapsone. In alkaline buffers radicals from fenoterol and its structural analog, metaproteronol, were detected by direct EPR. Analysis of these spectra suggests that oxidation of fenoterol and metaproterenol, but not terbutaline, causes their transformation through intramolecular cyclization by addition of their amino nitrogen to the aromatic ring. Together, these results indicate that phenolic β2-agonists function as substrates for airway peroxidases and that the resulting products differ in their structural and functional properties from their parent compounds. They also suggest that these transformations can be modulated by pharmacological approaches using appropriate peroxidase inhibitors or alternative substrates. These processes may affect therapeutic efficacy and also play a role in adverse reactions of the β2-agonists. PMID:19462961

Peroxidative metabolism of beta2-agonists salbutamol and fenoterol and their analogues.

PubMed

Reszka, Krzysztof J; McGraw, Dennis W; Britigan, Bradley E

2009-06-01

Phenolic beta(2)-adrenoreceptor agonists salbutamol, fenoterol, and terbutaline relax smooth muscle cells that relieve acute airway bronchospasm associated with asthma. Why their use sometimes fails to relieve bronchospasm and why the drugs appear to be less effective in patients with severe asthma exacerbations remains unclear. We show that in the presence of hydrogen peroxide, both myeloperoxidase, secreted by activated neutrophils present in inflamed airways, and lactoperoxidase, which is naturally present in the respiratory system, catalyze oxidation of these beta(2)-agonists. Azide, cyanide, thiocyanate, ascorbate, glutathione, and methimazole inhibited this process, while methionine was without effect. Inhibition by ascorbate and glutathione was associated with their oxidation to corresponding radical species by the agonists' derived phenoxyl radicals. Using electron paramagnetic resonance (EPR), we detected free radical metabolites from beta(2)-agonists by spin trapping with 2-methyl-2-nitrosopropane (MNP). Formation of these radicals was inhibited by pharmacologically relevant concentrations of methimazole and dapsone. In alkaline buffers, radicals from fenoterol and its structural analogue, metaproteronol, were detected by direct EPR. Analysis of these spectra suggests that oxidation of fenoterol and metaproterenol, but not terbutaline, causes their transformation through intramolecular cyclization by addition of their amino nitrogen to the aromatic ring. Together, these results indicate that phenolic beta(2)-agonists function as substrates for airway peroxidases and that the resulting products differ in their structural and functional properties from their parent compounds. They also suggest that these transformations can be modulated by pharmacological approaches using appropriate peroxidase inhibitors or alternative substrates. These processes may affect therapeutic efficacy and also play a role in adverse reactions of the beta(2)-agonists.

Extracellular matrix-associated proteome changes during non-host resistance in citrus-Xanthomonas interactions.

PubMed

Swaroopa Rani, Tirupaati; Podile, Appa Rao

2014-04-01

Non-host resistance (NHR) is a most durable broad-spectrum resistance employed by the plants to restrict majority of pathogens. Plant extracellular matrix (ECM) is a critical defense barrier. Understanding ECM responses during interaction with non-host pathogen will provide insights into molecular events of NHR. In this study, the ECM-associated proteome was compared during interaction of citrus with pathogen Xanthomonas axonopodis pv. citri (Xac) and non-host pathogen Xanthomonas oryzae pv. oryzae (Xoo) at 8, 16, 24 and 48 h post inoculation. Comprehensive analysis of ECM-associated proteins was performed by extracting wall-bound and soluble ECM components using both destructive and non-destructive procedures. A total of 53 proteins was differentially expressed in citrus-Xanthomonas host and non-host interaction, out of which 44 were identified by mass spectrometry. The differentially expressed proteins were related to (1) defense-response (5 pathogenesis-related proteins, 3 miraculin-like proteins (MIR, MIR1 and MIR2) and 2 proteases); (2) enzymes of reactive oxygen species (ROS) metabolism [Cu/Zn superoxide dismutase (SOD), Fe-SOD, ascorbate peroxidase and 2-cysteine-peroxiredoxin]; (3) signaling (lectin, curculin-like lectin and concanavalin A-like lectin kinase); and (4) cell-wall modification (α-xylosidase, glucan 1, 3 β-glucosidase, xyloglucan endotransglucosylase/hydrolase). The decrease in ascorbate peroxidase and cysteine-peroxiredoxin could be involved in maintenance of ROS levels. Increase in defense, cell-wall remodeling and signaling proteins in citrus-Xoo interaction suggests an active involvement of ECM in execution of NHR. Partially compromised NHR in citrus against Xoo, upon Brefeldin A pre-treatment supported the role of non-classical secretory proteins in this phenomenon. © 2013 Scandinavian Plant Physiology Society.

Effect of Inoculation with Glomus versiforme on Cadmium Accumulation, Antioxidant Activities and Phytochelatins of Solanum photeinocarpum

PubMed Central

Tan, Shi-Yun; Jiang, Qiu-Yun; Zhuo, Feng; Liu, Hui; Wang, Yu-Tao; Li, Shao-Shan; Ye, Zhi-Hong; Jing, Yuan-Xiao

2015-01-01

The plant growth, phosphate acquisition, Cd translocation, phytochelatins (PCs) production and antioxidant parameters [superoxide dismutase (SOD), catalase (CAT), guaiacol peroxidase (POD), ascorbate peroxidase (APX), glutathione reductase (GR), glutathione (GSH), ascorbate (ASA) and malonaldehyde (MDA)] were investigated in Cd-hyperaccumulator Solanum photeinocarpum inoculated with Glomus versiforme BGC GD01C (Gv) in Cd-added soils (0, 5, 10, 20, 40 mg Cd kg-1 soil). Mycorrhizal colonization rates were generally high (from 77% to 94%), and hardly affected by Cd. Gv colonization significantly enhanced P acquisition, growth and total Cd uptakes in both shoots and roots of S. photeinocarpum at all Cd levels. Meanwhile, Gv symbiosis significantly increased Cd concentration in the roots, and decreased Cd concentration in the shoots at all Cd levels, which indicates that Gv could promote phytostabilization by enhancing Cd accumulation in the roots to inhibit its translocation to shoots and the “dilution effects” linked to an increase in plant dry matter yield and a reduced Cd partitioning to shoots. Moreover, the improvement of CAT, POD and APX activities in the leaves of mycorrhizal plants infers that Gv symbiosis helped S. photeinocarpum to relieve oxidative damage to biomolecules in Cd-contaminated soil. The evident decline of MDA content in the leaves of mycorrhizal plants indicates that Gv symbiosis evidently improved antioxidant activities, and the enhancement of PCs production in the leaves of mycorrhizal plants suggests that Gv-inoculated plant may be more efficient to relieve Cd phytotoxicity. Therefore, the possible mechanisms of Cd phytotoxicity alleviation by Gv can be concluded as the decline of Cd concentration in the shoots and the improvement of P acquisition, PCs production and activities of CAT, POD, APX in mycorrhizal plants. PMID:26176959

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

PubMed

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.

Glutathione peroxidase deficiency exacerbates ischemia-reperfusion injury in male but not female myocardium: insights into antioxidant compensatory mechanisms.

PubMed

Lim, Chee Chew; Bryan, Nathan S; Jain, Mohit; Garcia-Saura, Maria F; Fernandez, Bernadette O; Sawyer, Douglas B; Handy, Diane E; Loscalzo, Joseph; Feelisch, Martin; Liao, Ronglih

2009-12-01

The female sex has been associated with increased resistance to acute myocardial ischemia-reperfusion (I/R) injury. While enhanced antioxidant capacity has been implicated in female cardioprotection, there is little evidence to support this assumption. Previous studies have shown an important role of cellular glutathione peroxidase (GPx1) in protection of the myocardium from I/R injury. Whether GPx1 is mechanistic in the protection of female myocardium, post-I/R, has not been examined. We utilized a murine model with homozygous deletion of GPx1 and examined its impact on postischemic myocardial recovery in male and female mice. Following I/R, male GPx1(-/-) hearts were more susceptible to contractile and diastolic dysfunction, and this was associated with increased protein carbonyls, a marker of oxidative stress. In contrast, GPx1 deficiency in female hearts did not exacerbate dysfunction or oxidative stress post-I/R. Both wild-type and GPx1(-/-) female hearts exhibited reduced creatine kinase leakage and a more favorable ascorbate redox status compared with males. Following I/R, female GPx1(-/-) hearts showed a comparable decrease in glutathione redox status as their male counterparts; however, they exhibited a greater decrease in nitrate-to-nitrite ratio, suggesting a higher consumption of nitrate in female GPx1(-/-) hearts. Our findings demonstrate that GPx1 is critical for cardioprotection during I/R in male, but not female, mice. The maintenance of cardioprotection in female mice lacking GPx1 post-I/R may be due to an improved ascorbate redox homeostasis and enhanced nitrate-to-nitrite conversion, which would predictably be accompanied by enhanced production of cardioprotective nitric oxide.

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

PubMed

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.

Haem oxygenase-1 is involved in salicylic acid-induced alleviation of oxidative stress due to cadmium stress in Medicago sativa

PubMed Central

Shen, Wenbiao

2012-01-01

This work examines the involvement of haem oxygenase-1 (HO-1) in salicylic acid (SA)-induced alleviation of oxidative stress as a result of cadmium (Cd) stress in alfalfa (Medicago sativa L.) seedling roots. CdCl2 exposure caused severe growth inhibition and Cd accumulation, which were potentiated by pre-treatment with zinc protoporphyrin (ZnPPIX), a potent HO-1 inhibitor. Pre-treatment of plants with the HO-1 inducer haemin or SA, both of which could induce MsHO1 gene expression, significantly reduced the inhibition of growth and Cd accumulation. The alleviation effects were also evidenced by a decreased content of thiobarbituric acid-reactive substances (TBARS). The antioxidant behaviour was confirmed by histochemical staining for the detection of lipid peroxidation and the loss of plasma membrane integrity. Furthermore, haemin and SA pre-treatment modulated the activities of ascorbate peroxidase (APX), superoxide dismutase (SOD), and guaiacol peroxidase (POD), or their corresponding transcripts. Significant enhancement of the ratios of reduced/oxidized homoglutathione (hGSH), ascorbic acid (ASA)/dehydroascorbate (DHA), and NAD(P)H/NAD(P)+, and expression of their metabolism genes was observed, consistent with a decreased reactive oxygen species (ROS) distribution in the root tips. These effects are specific for HO-1, since ZnPPIX blocked the above actions, and the aggravated effects triggered by SA plus ZnPPIX were differentially reversed when carbon monoxide (CO) or bilirubin (BR), two catalytic by-products of HO-1, was added. Together, the results suggest that HO-1 is involved in the SA-induced alleviation of Cd-triggered oxidative stress by re-establishing redox homeostasis. PMID:22915740

An N-terminal peptide extension results in efficient expression, but not secretion, of a synthetic horseradish peroxidase gene in transgenic tobacco.

PubMed

Kis, Mihaly; Burbridge, Emma; Brock, Ian W; Heggie, Laura; Dix, Philip J; Kavanagh, Tony A

2004-03-01

Native horseradish (Armoracia rusticana) peroxidase, HRP (EC 1.11.1.7), isoenzyme C is synthesized with N-terminal and C-terminal peptide extensions, believed to be associated with protein targeting. This study aimed to explore the specific functions of these extensions, and to generate transgenic plants with expression patterns suitable for exploring the role of peroxidase in plant development and defence. Transgenic Nicotiana tabacum (tobacco) plants expressing different versions of a synthetic horseradish peroxidase, HRP, isoenzyme C gene were constructed. The gene was engineered to include additional sequences coding for either the natural N-terminal or the C-terminal extension or both. These constructs were placed under the control of a constitutive promoter (CaMV-35S) or the tobacco RUBISCO-SSU light inducible promoter (SSU) and introduced into tobacco using Agrobacterium-mediated transformation. To study the effects of the N- and C-terminal extensions, the localization of recombinant peroxidase was determined using biochemical and molecular techniques. Transgenic tobacco plants can exhibit a ten-fold increase in peroxidase activity compared with wild-type tobacco levels, and the majority of this activity is located in the symplast. The N-terminal extension is essential for the production of high levels of recombinant protein, while the C-terminal extension has little effect. Differences in levels of enzyme activity and recombinant protein are reflected in transcript levels. There is no evidence to support either preferential secretion or vacuolar targeting of recombinant peroxidase in this heterologous expression system. This leads us to question the postulated targeting roles of these peptide extensions. The N-terminal extension is essential for high level expression and appears to influence transcript stability or translational efficiency. Plants have been generated with greatly elevated cytosolic peroxidase activity, and smaller increases in apoplastic activity. These will be valuable for exploring the role of these enzymes in stress amelioration and plant development.

An N‐terminal Peptide Extension Results in Efficient Expression, but not Secretion, of a Synthetic Horseradish Peroxidase Gene in Transgenic Tobacco

PubMed Central

KIS, MIHALY; BURBRIDGE, EMMA; BROCK, IAN W.; HEGGIE, LAURA; DIX, PHILIP J.; KAVANAGH, TONY A.

2004-01-01

• Background and Aims Native horseradish (Armoracia rusticana) peroxidase, HRP (EC 1.11.1.7), isoenzyme C is synthesized with N‐terminal and C‐terminal peptide extensions, believed to be associated with protein targeting. This study aimed to explore the specific functions of these extensions, and to generate transgenic plants with expression patterns suitable for exploring the role of peroxidase in plant development and defence. • Methods Transgenic Nicotiana tabacum (tobacco) plants expressing different versions of a synthetic horseradish peroxidase, HRP, isoenzyme C gene were constructed. The gene was engineered to include additional sequences coding for either the natural N‐terminal or the C‐terminal extension or both. These constructs were placed under the control of a constitutive promoter (CaMV‐35S) or the tobacco RUBISCO‐SSU light inducible promoter (SSU) and introduced into tobacco using Agrobacterium‐mediated transformation. To study the effects of the N‐ and C‐terminal extensions, the localization of recombinant peroxidase was determined using biochemical and molecular techniques. • Key Results Transgenic tobacco plants can exhibit a ten‐fold increase in peroxidase activity compared with wild‐type tobacco levels, and the majority of this activity is located in the symplast. The N‐terminal extension is essential for the production of high levels of recombinant protein, while the C‐terminal extension has little effect. Differences in levels of enzyme activity and recombinant protein are reflected in transcript levels. • Conclusions There is no evidence to support either preferential secretion or vacuolar targeting of recombinant peroxidase in this heterologous expression system. This leads us to question the postulated targeting roles of these peptide extensions. The N‐terminal extension is essential for high level expression and appears to influence transcript stability or translational efficiency. Plants have been generated with greatly elevated cytosolic peroxidase activity, and smaller increases in apoplastic activity. These will be valuable for exploring the role of these enzymes in stress amelioration and plant development. PMID:14749254

Thermosonication as a potential quality enhancement technique of apple juice.

PubMed

Abid, Muhammad; Jabbar, Saqib; Hu, Bing; Hashim, Malik Muhammad; Wu, Tao; Lei, Shicheng; Khan, Muhammad Ammar; Zeng, Xiaoxiong

2014-05-01

Enzymatic browning and microbial growth lead to quality losses in apple products. In the present study, fresh apple juice was thermosonicated using ultrasound in-bath (25 kHz, 30 min, 0.06 W cm(-3)) and ultrasound with-probe sonicator (20 kHz, 5 and 10 min, 0.30 W cm(-3)) at 20, 40 and 60°C for inactivation of enzymes (polyphenolase, peroxidase and pectinmethylesterase) and microflora (total plate count, yeast and mold). Additionally, ascorbic acid, total phenolics, flavonoids, flavonols, pH, titratable acidity, (°)Brix and color values influenced by thermosonication were investigated. The highest inactivation of enzymes was obtained in ultrasound with-probe at 60°C for 10 min, and the microbial population was completely inactivated at 60°C. The retention of ascorbic acid, total phenolics, flavonoids and flavonols were significantly higher in ultrasound with-probe than ultrasound in-bath at 60°C. These results indicated the usefulness of thermosonication for apple juice processing at low temperature, for enhanced inactivation of enzymes and microorganisms. Copyright © 2013 Elsevier B.V. All rights reserved.

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

PubMed

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.

Ascorbic Acid Enhances the Accumulation of Polycyclic Aromatic Hydrocarbons (PAHs) in Roots of Tall Fescue (Festuca arundinacea Schreb.)

PubMed Central

Gao, Yanzheng; Li, Hui; Gong, Shuaishuai

2012-01-01

Plant contamination by polycyclic aromatic hydrocarbons (PAHs) is crucial to food safety and human health. Enzyme inhibitors are commonly utilized in agriculture to control plant metabolism of organic components. This study revealed that the enzyme inhibitor ascorbic acid (AA) significantly reduced the activities of peroxidase (POD) and polyphenol oxidase (PPO), thus enhancing the potential risks of PAH contamination in tall fescue (Festuca arundinacea Schreb.). POD and PPO enzymes in vitro effectively decomposed naphthalene (NAP), phenanthrene (PHE) and anthracene (ANT). The presence of AA reduced POD and PPO activities in plants, and thus was likely responsible for enhanced PAH accumulation in tall fescue. This conclusion is supported by the significantly enhanced uptake of PHE in plants in the presence of AA, and the positive correlation between enzyme inhibition efficiencies and the rates of metabolism of PHE in tall fescue roots. This study provides a new perspective, that the common application of enzyme inhibitors in agricultural production could increase the accumulation of organic contaminants in plants, hence enhancing risks to food safety and quality. PMID:23185628

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

PubMed

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.

Effects of short-term anoxia treatment on browning of fresh-cut Chinese water chestnut in relation to antioxidant activity.

PubMed

You, Yanli; Jiang, Yueming; Sun, Jian; Liu, Hai; Song, Lili; Duan, Xuewu

2012-06-01

The effects of short-term anoxia pre-treatment on browning of fresh-cut Chinese water chestnut (CWC), stored at 4°C, in relation to antioxidant activity were investigated. CWC slices were exposed to pure N 2 for 4h and then stored at 4°C for 18d. Anoxia significantly inhibited browning of CWC slices during storage, accompanied by lower contents of malondialdehyde, H 2 O 2 , and lipoxygenase activity. Furthermore, anoxia induced the activities of superoxide dismutase and ascorbate peroxidase, which could benefit scavenging reactive oxygen species and alleviating lipid peroxidation. In addition, better maintenance of reducing power and free-radical-scavenging activities against α,α-diphenyl-β-picrylhydrazy (DPPH), superoxide anions and hydroxyl was observed in N 2 -treated CWC slices, with higher phenolic compounds and ascorbic acid contents. Collectively, these finds suggest that N 2 pre-treatment enhanced enzymatic and non-enzymatic antioxidant activity in CWC slices, and thereby contributed to alleviating lipid peroxidation and maintenance of storage quality. Copyright © 2011 Elsevier Ltd. All rights reserved.

Lincomycin Biosynthesis Involves a Tyrosine Hydroxylating Heme Protein of an Unusual Enzyme Family

PubMed Central

Novotna, Jitka; Olsovska, Jana; Novak, Petr; Mojzes, Peter; Chaloupkova, Radka; Kamenik, Zdenek; Spizek, Jaroslav; Kutejova, Eva; Mareckova, Marketa; Tichy, Pavel; Damborsky, Jiri; Janata, Jiri

2013-01-01

The gene lmbB2 of the lincomycin biosynthetic gene cluster of Streptomyces lincolnensis ATCC 25466 was shown to code for an unusual tyrosine hydroxylating enzyme involved in the biosynthetic pathway of this clinically important antibiotic. LmbB2 was expressed in Escherichia coli, purified near to homogeneity and shown to convert tyrosine to 3,4-dihydroxyphenylalanine (DOPA). In contrast to the well-known tyrosine hydroxylases (EC 1.14.16.2) and tyrosinases (EC 1.14.18.1), LmbB2 was identified as a heme protein. Mass spectrometry and Soret band-excited Raman spectroscopy of LmbB2 showed that LmbB2 contains heme b as prosthetic group. The CO-reduced differential absorption spectra of LmbB2 showed that the coordination of Fe was different from that of cytochrome P450 enzymes. LmbB2 exhibits sequence similarity to Orf13 of the anthramycin biosynthetic gene cluster, which has recently been classified as a heme peroxidase. Tyrosine hydroxylating activity of LmbB2 yielding DOPA in the presence of (6R)-5,6,7,8-tetrahydro-L-biopterin (BH4) was also observed. Reaction mechanism of this unique heme peroxidases family is discussed. Also, tyrosine hydroxylation was confirmed as the first step of the amino acid branch of the lincomycin biosynthesis. PMID:24324587

Cu0.89Zn0.11O, A New Peroxidase-Mimicking Nanozyme with High Sensitivity for Glucose and Antioxidant Detection.

PubMed

Nagvenkar, Anjani P; Gedanken, Aharon

2016-08-31

Nanomaterial-based enzyme mimetics (nanozymes) is an emerging field of research that promises to produce alternatives to natural enzymes for a variety of applications. The search for the most cost-effective and efficient inorganic nanomaterials, such as metal oxides, cannot be won by pristine CuO. However, unlike CuO, the Zn-doped CuO (Zn-CuO) nanoparticles reported in this paper reveal superior peroxidase-like enzyme activity. This places Zn-CuO in a good position to participate in a range of activities aimed at developing diverse enzyme applications. The peroxidase-like activity was tested and confirmed against various chromogenic substrates in the presence of H2O2 and obeyed the Michaelis-Menten enzymatic pathway. The mechanism of enhanced enzymatic activity was proved by employing terephthalic acid as a fluorescence probe and by electron spin resonance. The nanozyme, when tested for the detection of glucose, showed a substantial enhancement in the detection selectivity. The limit of detection (LOD) was also decreased reaching a limit as low as 0.27 ppm. Such a low LOD has not been reported so far for the metal oxides without any surface modifications. Moreover, the nanozyme (Zn-CuO) was utilized to detect the three antioxidants tannic acid, tartaric acid, and ascorbic acid and the relative strength of their antioxidant capacity was compared.

Engineered ascorbate peroxidase as a genetically encoded reporter for electron microscopy.

PubMed

Martell, Jeffrey D; Deerinck, Thomas J; Sancak, Yasemin; Poulos, Thomas L; Mootha, Vamsi K; Sosinsky, Gina E; Ellisman, Mark H; Ting, Alice Y

2012-11-01

Electron microscopy (EM) is the standard method for imaging cellular structures with nanometer resolution, but existing genetic tags are inactive in most cellular compartments or require light and can be difficult to use. Here we report the development of 'APEX', a genetically encodable EM tag that is active in all cellular compartments and does not require light. APEX is a monomeric 28-kDa peroxidase that withstands strong EM fixation to give excellent ultrastructural preservation. We demonstrate the utility of APEX for high-resolution EM imaging of a variety of mammalian organelles and specific proteins using a simple and robust labeling procedure. We also fused APEX to the N or C terminus of the mitochondrial calcium uniporter (MCU), a recently identified channel whose topology is disputed. These fusions give EM contrast exclusively in the mitochondrial matrix, suggesting that both the N and C termini of MCU face the matrix. Because APEX staining is not dependent on light activation, APEX should make EM imaging of any cellular protein straightforward, regardless of the size or thickness of the specimen.

Glutathione biosynthesis plays an important role against 4-tert-octylphenol-induced oxidative stress in Ceratophyllum demersum.

PubMed

Cahyanurani, Annisa' Bias; Chiu, Kuo-Hsun; Wu, Tsung-Meng

2017-09-01

4-tert-octylphenol (OP) is a persistent environmental pollutant with an endocrine-disrupting property. In the present study, we examined the effect of various concentrations of OP (0, 0.5, 1, 1.5, 2 and 3 mg L -1 ) applied to an aquatic plant, the submersed macrophyte Ceratophyllum demersum. The toxic effect caused by OP inhibited the plant's growth rate, reduced total chlorophyll content and increased levels of the reactive oxygen species (ROS) O 2 •- and H 2 O 2 . OP treatment significantly increased the activities of antioxidant enzymes including superoxide dismutase, guaiacol peroxidase, glutathione reductase and ascorbate peroxidase. The contents of the non-enzymatic antioxidant glutathione (GSH) and ratio of GSH to glutathione disulfide were markedly increased with OP treatment. Pretreatment with buthionine sulfoximine, a specific and potent inhibitor of GSH biosynthesis, significantly reduced total GSH content and conferred a more severe toxic phenotype on OP exposure. Thus, with OP-induced oxidative stress, C. demersum might actively regulate the antioxidant machinery, especially the biosynthesis and redox state of GSH. Copyright © 2017 Elsevier Ltd. All rights reserved.

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

PubMed

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 iron toxicity in Schinus terebinthifolius Raddi (Anacardiaceae) by humic substances.

PubMed

Dobbss, Leonardo Barros; Dos Santos, Tamires Cruz; Pittarello, Marco; de Souza, Sávio Bastos; Ramos, Alessandro Coutinho; Busato, Jader Galba

2018-04-01

One of the industrial pillars of Espírito Santo state, South East of Brazil, is iron-mining products processing. This activity brings to a high level of coastal pollution due to deposition of iron particulate on fragile ecosystems as mangroves and restinga. Schinus therebinthifolius (aroeira) is a widespread restinga species. This work tested iron toxicity alleviation by vermicompost humic substances (HS) added to aroeira seedlings in hydroponic conditions. Catalase, peroxidase, and ascorbate peroxidase are antioxidant enzymes that work as reactive oxygen species (ROS) scavengers: they increase their activity as an answer to ROS concentration rise that is the consequence of metal accumulation or humic substance stimulation. S. terebinthifolius seedlings treated with HS and Fe augmented their antioxidant enzyme activities significantly less than seedlings treated separately with HS and Fe; their significantly lower Fe accumulation and the slight increase of root and leaf area confirm the biostimulating effect of HS and their role in blocking Fe excess outside the roots. The use of HS can be useful for the recovery of areas contaminated by heavy metals.

Effects of CO2 Enrichment on Growth and Development of Impatiens hawkeri

PubMed Central

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

Mercury-induced biochemical and proteomic changes in rice roots.

PubMed

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.

Effect of Sulfated Chitooligosaccharides on Wheat Seedlings (Triticum aestivum L.) under Salt Stress.

PubMed

Zou, Ping; Li, Kecheng; Liu, Song; He, Xiaofei; Zhang, Xiaoqian; Xing, Ronge; Li, Pengcheng

2016-04-13

In this study, sulfated chitooligosaccharide (SCOS) was applied to wheat seedlings to investigate its effect on the plants' defense response under salt stress. The antioxidant enzyme activities, chlorophyll contents, and fluorescence characters of wheat seedlings were determined at a certain time. The results showed that treatment with exogenous SCOS could decrease the content of malondialdehyde, increase the chlorophyll contents, and modulate fluorescence characters in wheat seedlings under salt stress. In addition, SCOS was able to regulate the activities of antioxidant enzymes containing superoxide dismutase, catalase, peroxidase, ascorbate peroxidase, glutathione reductase, and dehydroascorbate reductase. Similarly, the mRNA expression levels of several antioxidant enzymes were efficiently modulated by SCOS. The results indicated that SCOS could alleviate the damage of salt stress by adjusting the antioxidant enzyme activities of plant. The effect of SCOS on the photochemical efficiency of wheat seedlings was associated with its enhanced capacity for antioxidant enzymes, which prevented structure degradation of the photosynthetic apparatus under NaCl stress. Furthermore, the effective activities of alleviating salt stress indicated the activities of SCOS were closely related with the sulfate group.

Airway Peroxidases Catalyze Nitration of the β2-Agonist Salbutamol and Decrease Its Pharmacological Activity

PubMed Central

Sallans, Larry; Macha, Stephen; Brown, Kari; McGraw, Dennis W.; Kovacic, Melinda Butsch; Britigan, Bradley E.

2011-01-01

β2-Agonists are the most effective bronchodilators for the rapid relief of asthma symptoms, but for unclear reasons, their effectiveness may be decreased during severe exacerbations. Because peroxidase activity and nitrogen oxides are increased in the asthmatic airway, we examined whether salbutamol, a clinically important β2-agonist, is subject to potentially inactivating nitration. When salbutamol was exposed to myeloperoxidase, eosinophil peroxidase or lactoperoxidase in the presence of hydrogen peroxide (H2O2) and nitrite (NO2−), both absorption spectroscopy and mass spectrometry indicated formation of a new metabolite with features expected for the nitrated drug. The new metabolites showed an absorption maximum at 410 nm and pKa of 6.6 of the phenolic hydroxyl group. In addition to nitrosalbutamol (m/z 285.14), a salbutamol-derived nitrophenol, formed by elimination of the formaldehyde group, was detected (m/z 255.13) by mass spectrometry. It is noteworthy that the latter metabolite was detected in exhaled breath condensates of asthma patients receiving salbutamol but not in unexposed control subjects, indicating the potential for β2-agonist nitration to occur in the inflamed airway in vivo. Salbutamol nitration was inhibited in vitro by ascorbate, thiocyanate, and the pharmacological agents methimazole and dapsone. The efficacy of inhibition depended on the nitrating system, with the lactoperoxidase/H2O2/NO2− being the most affected. Functionally, nitrated salbutamol showed decreased affinity for β2-adrenergic receptors and impaired cAMP synthesis in airway smooth muscle cells compared with the native drug. These results suggest that under inflammatory conditions associated with asthma, phenolic β2-agonists may be subject to peroxidase-catalyzed nitration that could potentially diminish their therapeutic efficacy. PMID:20974700

Large variability in ambient ozone sensitivity across 19 ethylenediurea-treated Chinese cultivars of soybean is driven by total ascorbate.

PubMed

Jiang, Lijun; Feng, Zhaozhong; Dai, Lulu; Shang, Bo; Paoletti, Elena

2018-02-01

The sensitivity of Chinese soybean cultivars to ambient ozone (O 3 ) in the field is unknown, although soybean is a major staple food in China. Using ethylenediurea (EDU) as an O 3 protectant, we tested the gas exchange, pigments, antioxidants and biomass of 19 cultivars exposed to 28ppm·hr AOT40 (accumulated O 3 over an hourly concentration threshold of 40ppb) over the growing season at a field site in China. By comparing the average biomass with and without EDU, we estimated the cultivar-specific sensitivity to O 3 and ranked the cultivars from very tolerant (<10% change) to highly sensitive (>45% change), which helps in choosing the best-suited cultivars for local cultivation. Higher lipid peroxidation and activity of the ascorbate peroxidase enzyme were major responses to O 3 damage, which eventually translated into lower biomass production. The constitutional level of total ascorbate in the leaves was the most important parameter explaining O 3 sensitivity among these cultivars. Surprisingly, the role of stomatal conductance was insignificant. These results will guide future breeding efforts towards more O 3 -tolerant cultivars in China, while strategies for implementing control measures of regional O 3 pollution are being implemented. Overall, these results suggest that present ambient O 3 pollution is a serious concern for soybean in China, which highlights the urgent need for policy-making actions to protect this critical staple food. Copyright © 2017. Published by Elsevier B.V.

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

PubMed

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.

The kinetics of the oxidation of cytochrome c by Paracoccus cytochrome c peroxidase.

PubMed

Gilmour, R; Goodhew, C F; Pettigrew, G W; Prazeres, S; Moura, J J; Moura, I

1994-06-15

In work that is complementary to our investigation of the spectroscopic features of the cytochrome c peroxidase from Paracoccus denitrificans [Gilmour, Goodhew, Pettigrew, Prazeres, Moura and Moura (1993) Biochem. J. 294, 745-752], we have studied the kinetics of oxidation of cytochrome c by this enzyme. The enzyme, as isolated, is in the fully oxidized form and is relatively inactive. Reduction of the high-potential haem at pH 6 with ascorbate results in partial activation of the enzyme. Full activation is achieved by addition of 1 mM CaCl2. Enzyme activation is associated with formation of a high-spin state at the oxidized low-potential haem. EGTA treatment of the oxidized enzyme prevents activation after reduction with ascorbate, while treatment with EGTA of the reduced, partially activated, form abolishes the activity. We conclude that the active enzyme is a mixed-valence form with the low-potential haem in a high-spin state that is stabilized by Ca2+. Dilution of the enzyme results in a progressive loss of activity, the extent of which depends on the degree of dilution. Most of the activity lost upon dilution can be recovered after reconcentration. The M(r) of the enzyme on molecular-exclusion chromatography is concentration-dependent, with a shift to lower values at lower concentrations. Values of M(r) obtained are intermediate between those of a monomer (39,565) and a dimer. We propose that the active form of the enzyme is a dimer which dissociates at high dilution to give inactive monomers. From the activity of the enzyme at different dilutions, a KD of 0.8 microM can be calculated for the monomerdimer equilibrium. The cytochrome c peroxidase oxidizes horse ferrocytochrome c with first-order kinetics, even at high ferrocytochrome c concentrations. The maximal catalytic-centre activity ('turnover number') under the assay conditions used is 62,000 min-1, with a half-saturating ferrocytochrome c concentration of 3.3 microM. The corresponding values for the Paracoccus cytochrome c-550 (presumed to be the physiological substrate) are 85,000 min-1 and 13 microM. However, in this case, the kinetics deviate from first-order progress curves at all ferrocytochrome c concentrations. Consideration of the periplasmic environment in Paracoccus denitrificans leads us to propose that the enzyme will be present as the fully active dimer supplied with saturating ferrocytochrome c-550.

Synthesis and antioxidant evaluation of (S,S)- and (R,R)-secoisolariciresinol diglucosides (SDGs)

PubMed Central

Mishra, Om P.; Simmons, Nicholas; Tyagi, Sonia; Pietrofesa, Ralph; Shuvaev, Vladimir V.; Valiulin, Roman A.; Heretsch, Philipp; Nicolaou, K. C.; Christofidou-Solomidou, Melpo

2013-01-01

Secoisolariciresinol diglucosides (SDGs) (S,S)-SDG-1 (major isomer in flaxseed) and (R,R)-SDG-2 (minor isomer in flaxseed) were synthesized from vanillin via secoisolariciresinol (6) and glucosyl donor 7 through a concise route that involved chromatographic separation of diastereomeric diglucoside derivatives (S,S)-8 and (R,R)-9. Synthetic (S,S)-SDG-1 and (R,R)-SDG-2 exhibited potent antioxidant properties (EC50 = 292.17 ± 27.71 μM and 331.94 ± 21.21 μM, respectively) which compared well with that of natural (S,S)-SDG-1 (EC50 = 275.24 ± 13.15 μM). These values are significantly lower than those of ascorbic acid (EC50 = 1129.32 ± 88.79 μM) and α-tocopherol (EC50 = 944.62 ± 148.00 μM). Compounds (S,S)-SDG-1 and (R,R)-SDG-2 also demonstrated powerful scavenging activities against hydroxyl [natural (S,S)-SDG-1: 3.68 ± 0.27; synthetic (S,S)-SDG-1: 2.09 ± 0.16; synthetic (R,R)-SDG-2: 1.96 ± 0.27], peroxyl [natural (S,S)-SDG-1: 2.55 ± 0.11; synthetic (S,S)-SDG-1: 2.20 ± 0.10; synthetic (R,R)-SDG-2: 3.03 ± 0.04] and DPPH [natural (S,S)-SDG-1: EC50 = 83.94 ± 2.80 μM; synthetic (S,S)-SDG-1: EC50 = 157.54 ± 21.30; synthetic (R,R)-SDG-2: EC50 = 123.63 ± 8.67] radicals. These results confirm previous studies with naturally occurring (S,S)-SDG-1 and establish both (S,S)-SDG-1 and (R,R)-SDG-2 as potent antioxidants and free radical scavengers for potential in vivo use. PMID:23978651

Dual peroxidase and colloidal gold-labeling study of angiotensin converting enzyme and angiotensin-like immunoreactivity in the rat subfornical organ.

PubMed

Pickel, V M; Chan, J; Ganten, D

1986-08-01

The cellular relationships between angiotensin converting enzyme (ACE) (EC 3.4.14.1) and angiotensin-like immunoreactivity (AGLI) were examined in the subfornical organ (SFO). Brains from adult rats were fixed by vascular perfusion with 3.75% acrolein and 2% paraformaldehyde. The region containing the SFO was then sectioned on a vibrating microtome. Partially permeabilized sections were immunocytochemically labeled using the peroxidase-antiperoxidase (PAP) or combined PAP and immunogold methods. Goat antiserum to ACE was localized to both non-neuronal and neuronal cells within the SFO. Intense peroxidase immunoreactivity for ACE was associated with the ventricular and basal surface of ependymal cells, the luminal surface of the vascular endothelium, portions of glial membranes exposed to extracellular spaces, and membranous organelles within neuronal processes. Two antisera raised in rabbits against angiotensin II showed peroxidase immunoreactivity within the extracellular spaces and throughout the cytoplasm of numerous axon terminals and a few perikarya and dendrites in the SFO. Axon terminals and dendrites also showed aggregates of AGLI in smooth membranes and vesicles near the plasmalemma. Gold labeling for AGLI was evident in only 6% of the axon terminals and in a smaller number of dendrites containing peroxidase immunoreactivity for ACE. The low incidence of terminals containing both markers appeared to at least partially reflect limited penetration of the 10 nm gold particles. These results provide the first ultrastructural evidence that ACE is associated with the plasmalemma and membranous organelles strategically located for interaction with precursors of angiotensin II or other peptides within the cerebrospinal fluid, extracellular spaces and neurons of the SFO.

Large Cellular Inclusions Accumulate in Arabidopsis Roots Exposed to Low-Sulfur Conditions1[OPEN

PubMed Central

Popov, Vladimir A.; Mathur, Jaideep; Benfey, Philip N.

2015-01-01

Sulfur is vital for primary and secondary metabolism in plant roots. To understand the molecular and morphogenetic changes associated with loss of this key macronutrient, we grew Arabidopsis (Arabidopsis thaliana) seedlings in low-sulfur conditions. These conditions induced a cascade of cellular events that converged to produce a profound intracellular phenotype defined by large cytoplasmic inclusions. The inclusions, termed low-sulfur Pox, show cell type- and developmental zone-specific localization. Transcriptome analysis suggested that low sulfur causes dysfunction of the glutathione/ascorbate cycle, which reduces flavonoids. Genetic and biochemical evidence indicated that low-sulfur Pox are the result of peroxidase-catalyzed oxidation of quercetin in roots grown under sulfur-depleted conditions. PMID:26099270

Proteomic profiling of γ-ECS overexpressed transgenic Nicotiana in response to drought stress.

PubMed

Kumar, Deepak; Datta, Riddhi; Sinha, Ragini; Ghosh, Aparupa; Chattopadhyay, Sharmila

2014-01-01

The contribution of Glutathione (GSH) in drought stress tolerance is an established fact. However, the proteins which are directly or indirectly related to the increased level of GSH in response to drought stress are yet to be known. To explore this, here, transgenic tobacco plants (NtGp11) overexpressing gamma-glutamylcysteine synthetase (γ-ECS) was tested for tolerance against drought stress. NtGp11 conferred tolerance to drought stress by increased germination rate, water retention, water recovery, chlorophyll, and proline content compared with wild-type plants. Semi-quantitative RT-PCR analysis revealed that the transcript levels of stress-responsive genes were higher in NtGp11 compared with wild-type in response to drought stress. Two-dimensional gel electrophoresis (2-DE) coupled with MALDI TOF-TOF MS/MS analysis has been used to identify 43 differentially expressed proteins in response to drought in wild-type and NtGp11 plants. The results demonstrated the up-accumulation of 58.1% of proteins among which 36%, 24%, and 20% of them were related to stress and defense, carbon metabolism and energy metabolism categories, respectively. Taken together, our results demonstrated that GSH plays an important role in combating drought stress in plants by inducing stress related genes and proteins like HSP70, chalcone synthase, glutathione peroxidase, thioredoxin peroxidase, ACC oxidase, and heme oxygenase I.

Proteomic profiling of γ-ECS overexpressed transgenic Nicotiana in response to drought stress.

PubMed

Kumar, Deepak; Datta, Riddhi; Sinha, Ragini; Ghosh, Aparupa; Chattopadhyay, Sharmila

2014-05-20

The contribution of Glutathione (GSH) in drought stress tolerance is an established fact. However, the proteins which are directly or indirectly related to the increased level of GSH in response to drought stress are yet to be known. To explore this, here, transgenic tobacco plants (NtGp 11) overexpressing gamma-glutamylcysteine synthetase (γ-ECS) was tested for tolerance against drought stress. NtGp 11 conferred tolerance to drought stress by increased germination rate, water retention, water recovery, chlorophyll, and proline content compared with wild-type plants. Semi-quantitative RT-PCR analysis revealed that the transcript levels of stress-responsive genes were higher in NtGp 11 compared with wild-type in response to drought stress. Two-dimensional gel electrophoresis (2-DE) coupled with MALDI TOF-TOF MS/MS analysis has been used to identify 43 differentially expressed proteins in response to drought in wild-type and NtGp 11 plants. The results demonstrated the up-accumulation of 58.1% of proteins among which 36%, 24%, and 20% of them were related to stress and defense, carbon metabolism and energy metabolism categories, respectively. Taken together, our results demonstrated that GSH plays an important role in combating drought stress in plants by inducing stress related genes and proteins like HSP70, chalcone synthase, glutathione peroxidase, thioredoxin peroxidase, ACC oxidase, and heme oxygenase I.

Comparative analyses of universal extraction buffers for assay of stress related biochemical and physiological parameters.

PubMed

Han, Chunyu; Chan, Zhulong; Yang, Fan

2015-01-01

Comparative efficiency of three extraction solutions, including the universal sodium phosphate buffer (USPB), the Tris-HCl buffer (UTHB), and the specific buffers, were compared for assays of soluble protein, free proline, superoxide radical (O2∙-), hydrogen peroxide (H2O2), and the antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT), guaiacol peroxidase (POD), ascorbate peroxidase (APX), glutathione peroxidase (GPX), and glutathione reductase (GR) in Populus deltoide. Significant differences for protein extraction were detected via sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and two-dimensional electrophoresis (2-DE). Between the two universal extraction buffers, the USPB showed higher efficiency for extraction of soluble protein, CAT, GR, O2∙-, GPX, SOD, and free proline, while the UTHB had higher efficiency for extraction of APX, POD, and H2O2. When compared with the specific buffers, the USPB showed higher extraction efficiency for measurement of soluble protein, CAT, GR, and O2∙-, parallel extraction efficiency for GPX, SOD, free proline, and H2O2, and lower extraction efficiency for APX and POD, whereas the UTHB had higher extraction efficiency for measurement of POD and H2O2. Further comparisons proved that 100 mM USPB buffer showed the highest extraction efficiencies. These results indicated that USPB would be suitable and efficient for extraction of soluble protein, CAT, GR, GPX, SOD, H2O2, O2∙-, and free proline.

Biotechnological potential of endophytic actinomycetes associated with Asteraceae plants: isolation, biodiversity and bioactivities.

PubMed

Tanvir, Rabia; Sajid, Imran; Hasnain, Shahida

2014-04-01

Endophytic actinomycetes from five Asteraceae plants were isolated and evaluated for their bioactivities. From Parthenium hysterophorus, Ageratum conyzoides, Sonchus oleraceus, Sonchus asper and Hieracium canadense, 42, 45, 90, 3, and 2 isolates, respectively, were obtained. Of the isolates, 86 (47.2 %) showed antimicrobial activity. Majority of the isolates were recovered from the roots (n = 127, 69.7 %). The dominant genus was Streptomyces (n = 96, 52.7 %), while Amycolatopsis, Pseudonocardia, Nocardia and Micromonospora were also recovered. Overall, 36 of the 86 isolates were significantly bioactivity while 18 (20.9 %) showed strong bioactivity. In total, 52.1 and 66.6 % showed potent cytotoxicity and antioxidant activities. The LC50 for 15 strains was <20 μg/ml. Compared to the ascorbate standard (EC50 0.34 μg/ml), all isolates gave impressive results with notable EC50 values of 0.65, 0.67, 0.74 and 0.79 μg/ml.

Impact of exogenous ascorbic acid on biochemical activities of rice callus treated with salt stress

NASA Astrophysics Data System (ADS)

Alhasnawi, Arshad Naji; Zain, Che Radziah Che Mohd; Kadhimi, Ahsan A.; Isahak, Anizan; Mohamad, Azhar; Ashraf, Mehdi Farshad; Doni, Febri; Yusoff, Wan Mohtar Wan

2016-11-01

The application of in vitro systems can lead to new methods of crop amelioration. This method has been widely utilized for breeding tenacities, particularly for stress tolerance selection. Salinity causes oxidative stress in callus by enhancing the production of Reactive Oxygen Species (ROS), resulting in an efficient antioxidant system. The exogenous application of ascorbic acid (AsA) is an important requirement for tolerance. The present study aimed to examine in vitro selection strategy for callus induction in rice mature embryo culture on MS culture medium and to produce salt-tolerant callus under sodium chloride (NaCl) and AsA conditions in callus rice variety, MR269. This study also highlights changes in the activities of proline and antioxidants peroxidase (POD), catalase (CAT) and superoxide dismutase (SOD) of callus under NaCl stress to understand their possible role in salt tolerance. However, various levels of exogenously applied AsA under saline conditions improved callus, and the antioxidant enzyme activities of AsA are related to resistance to oxidative stress. Our results provide strong support for the hypothesis that AsA-dependent antioxidant enzymes play a significant role in the salinity tolerance of callus rice.

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

PubMed

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.

Regions of the bread wheat D genome associated with variation in key photosynthesis traits and shoot biomass under both well watered and water deficient conditions.

PubMed

Osipova, Svetlana; Permyakov, Alexey; Permyakova, Marina; Pshenichnikova, Tatyana; Verkhoturov, Vasiliy; Rudikovsky, Alexandr; Rudikovskaya, Elena; Shishparenok, Alexandr; Doroshkov, Alexey; Börner, Andreas

2016-05-01

A quantitative trait locus (QTL) approach was taken to reveal the genetic basis in wheat of traits associated with photosynthesis during a period of exposure to water deficit stress. The performance, with respect to shoot biomass, gas exchange and chlorophyll fluorescence, leaf pigment content and the activity of various ascorbate-glutathione cycle enzymes and catalase, of a set of 80 wheat lines, each containing a single chromosomal segment introgressed from the bread wheat D genome progenitor Aegilops tauschii, was monitored in plants exposed to various water regimes. Four of the seven D genome chromosomes (1D, 2D, 5D, and 7D) carried clusters of both major (LOD >3.0) and minor (LOD between 2.0 and 3.0) QTL. A major QTL underlying the activity of glutathione reductase was located on chromosome 2D, and another, controlling the activity of ascorbate peroxidase, on chromosome 7D. A region of chromosome 2D defined by the microsatellite locus Xgwm539 and a second on chromosome 7D flanked by the marker loci Xgwm1242 and Xgwm44 harbored a number of QTL associated with the water deficit stress response.

Primary, Secondary Metabolites, Photosynthetic Capacity and Antioxidant Activity of the Malaysian Herb Kacip Fatimah (Labisia Pumila Benth) Exposed to Potassium Fertilization under Greenhouse Conditions

PubMed Central

Ibrahim, Mohd Hafiz; Jaafar, Hawa Z. E.; Karimi, Ehsan; Ghasemzadeh, Ali

2012-01-01

A randomized complete block design was used to characterize the relationship between production of total phenolics, flavonoids, ascorbic acid, carbohydrate content, leaf gas exchange, phenylalanine ammonia-lyase (PAL), soluble protein, invertase and antioxidant enzyme activities (ascorbate peroxidase (APX), catalase (CAT) and superoxide dismutase (SOD) in Labisia pumila Benth var. alata under four levels of potassium fertilization experiments (0, 90, 180 and 270 kg K/ha) conducted for 12 weeks. It was found that the production of total phenolics, flavonoids, ascorbic acid and carbohydrate content was affected by the interaction between potassium fertilization and plant parts. As the potassium fertilization levels increased from 0 to 270 kg K/ha, the production of soluble protein and PAL activity increased steadily. At the highest potassium fertilization (270 kg K/ha) L. pumila exhibited significantly higher net photosynthesis (A), stomatal conductance (gs), intercellular CO2 (Ci), apparent quantum yield (ξ) and lower dark respiration rates (Rd), compared to the other treatments. It was found that the production of total phenolics, flavonoids and ascorbic acid are also higher under 270 kg K/ha compared to 180, 90 and 0 kg K/ha. Furthermore, from the present study, the invertase activity was also found to be higher in 270 kg K/ha treatment. The antioxidant enzyme activities (APX, CAT and SOD) were lower under high potassium fertilization (270 kg K/ha) and have a significant negative correlation with total phenolics and flavonoid production. From this study, it was observed that the up-regulation of leaf gas exchange and downregulation of APX, CAT and SOD activities under high supplementation of potassium fertilizer enhanced the carbohydrate content that simultaneously increased the production of L. pumila secondary metabolites, thus increasing the health promoting effects of this plant. PMID:23203128

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

PubMed

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.

Differential antioxidative response of tolerant and sensitive maize (Zea mays L.) genotypes to drought stress at reproductive stage.

PubMed

Chugh, Vishal; Kaur, Narinder; Grewal, M S; Gupta, Anil K

2013-04-01

The role of oxidative stress management was evaluated in two maize (Zea mays L.) genotypes - Parkash (drought-resistant) and Paras (drought-sensitive), subjected to drought stress during reproductive stage. Alterations in their antioxidant pools - glutathione (GSH) and ascorbic acid (AsA) combined with activities of enzymes glutathione reductase (GR), ascorbate peroxidase (APX), peroxidase (POX) and catalase (CAT) involved in defense against oxidative stress and stress parameters, namely chlorophyll (Chl), hydrogen peroxide (H2O2) and malondialdehyde (MDA) were investigated in flag leaves from silk emergence till maturity. The drought caused transient increase in GR, APX, POX and CAT activities in drought-tolerant genotype (Parkash) which decreased at later stages with the extended period of drought stress. However, in Paras, drought stress caused decrease in activities of GR and CAT from initial period of stress till the end of experiment, except for POX which showed slight increase in activity. A significant increase in GSH content was observed in Parkash till 35 days after silking (DAS), whereas in Paras, GSH content remained lower than irrigated till maturity. Parkash which had higher AsA and Chl contents, also showed lower H2O2 and MDA levels than Paras under drought stress conditions. However, at the later stages, decline in antioxidant enzyme activities in Parkash due to severe drought stress led to enhanced membrane damage, as revealed by the accumulation of MDA. Our data indicated that significant activation of antioxidant system in Parkash might be responsible for its drought-tolerant behavior under drought stress and helped it to cope with the stress up to a definite period. Thus, the results indicate that antioxidant status and lipid peroxidation in flag leaves can be used as indices of drought tolerance in maize plants and also as potential biochemical targets for the crop improvement programmes to develop drought-tolerant cultivars.

Ascorbate Peroxidase, a Key Molecule Regulating Amphotericin B Resistance in Clinical Isolates of Leishmania donovani

PubMed Central

Kumar, Ashish; Das, Sushmita; Purkait, Bidyut; Sardar, Abul Hasan; Ghosh, Ayan Kumar; Dikhit, Manas Ranjan; Abhishek, Kumar

2014-01-01

Amphotericin B (AmB), a polyene macrolide, is now a first-line treatment of visceral leishmaniasis cases refractory to antimonials in India. AmB relapse cases and the emergence of secondary resistance have now been reported. To understand the mechanism of AmB, differentially expressed genes in AmB resistance strains were identified by a DNA microarray and real-time reverse transcriptase PCR (RT-PCR) approach. Of the many genes functionally overexpressed in the presence of AmB, the ascorbate peroxidase gene from a resistant Leishmania donovani strain (LdAPx gene) was selected because the gene is present only in Leishmania, not in humans. Apoptosis-like cell death after exposure to AmB was investigated in a wild-type (WT) strain in which the LdAPx gene was overexpressed and in AmB-sensitive and -resistant strains. A higher percentage of apoptosis-like cell death after AmB treatment was noticed in the sensitive strain than in both the resistant isolate and the strain sensitive to LdAPx overexpression. This event is preceded by AmB-induced formation of reactive oxygen species and elevation of the cytosolic calcium level. Enhanced cytosolic calcium was found to be responsible for depolarization of the mitochondrial membrane potential and the release of cytochrome c (Cyt c) into the cytosol. The redox behavior of Cyt c showed that it has a role in the regulation of apoptosis-like cell death by activating metacaspase- and caspase-like proteins and causing concomitant nuclear alterations, as determined by terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end labeling (TUNEL) and DNA fragmentation in the resistant strain. The present study suggests that constitutive overexpression of LdAPx in the L. donovani AmB-resistant strain prevents cells from the deleterious effect of oxidative stress, i.e., mitochondrial dysfunction and cellular death induced by AmB. PMID:25114128

Ascorbate peroxidase, a key molecule regulating amphotericin B resistance in clinical isolates of Leishmania donovani.

PubMed

Kumar, Ashish; Das, Sushmita; Purkait, Bidyut; Sardar, Abul Hasan; Ghosh, Ayan Kumar; Dikhit, Manas Ranjan; Abhishek, Kumar; Das, Pradeep

2014-10-01

Amphotericin B (AmB), a polyene macrolide, is now a first-line treatment of visceral leishmaniasis cases refractory to antimonials in India. AmB relapse cases and the emergence of secondary resistance have now been reported. To understand the mechanism of AmB, differentially expressed genes in AmB resistance strains were identified by a DNA microarray and real-time reverse transcriptase PCR (RT-PCR) approach. Of the many genes functionally overexpressed in the presence of AmB, the ascorbate peroxidase gene from a resistant Leishmania donovani strain (LdAPx gene) was selected because the gene is present only in Leishmania, not in humans. Apoptosis-like cell death after exposure to AmB was investigated in a wild-type (WT) strain in which the LdAPx gene was overexpressed and in AmB-sensitive and -resistant strains. A higher percentage of apoptosis-like cell death after AmB treatment was noticed in the sensitive strain than in both the resistant isolate and the strain sensitive to LdAPx overexpression. This event is preceded by AmB-induced formation of reactive oxygen species and elevation of the cytosolic calcium level. Enhanced cytosolic calcium was found to be responsible for depolarization of the mitochondrial membrane potential and the release of cytochrome c (Cyt c) into the cytosol. The redox behavior of Cyt c showed that it has a role in the regulation of apoptosis-like cell death by activating metacaspase- and caspase-like proteins and causing concomitant nuclear alterations, as determined by terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end labeling (TUNEL) and DNA fragmentation in the resistant strain. The present study suggests that constitutive overexpression of LdAPx in the L. donovani AmB-resistant strain prevents cells from the deleterious effect of oxidative stress, i.e., mitochondrial dysfunction and cellular death induced by AmB. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

Effect of iron on lipid peroxidation, and enzymatic and non-enzymatic antioxidants and bacoside-A content in medicinal plant Bacopa monnieri L.

PubMed

Sinha, Sarita; Saxena, Rohit

2006-03-01

The effect of Fe was investigated in medicinally important plant, Bacopa monnieri L. and the response on malondialdehyde (MDA) content, superoxide dismutase (SOD), peroxidase (POD) and ascorbate peroxidase (APX) was found different in roots and leaves of the metal treated plants. Iron induced stress was observed as indicated by high level of lipid peroxidation, being more steep increase in leaves than roots. In roots, SOD activity was found to increase in metal treated plants except 80 and 160 microM at 72 h, whereas, it decreased in leaves except 10 and 40 microM after 48 h as compared to their respective controls. Among H2O2 eliminating enzymes, POD activity increased in roots, however, it decreased in leaves except at 10 and 40 microM Fe after 48 h as compared to control. At 24 and 48 h, APX activity and ascorbic acid content followed the similar trend and were found to increase in both parts of the metal treated plants as compared to their respective controls. The level of cysteine content in the roots increased at initial period of exposure; however, no marked change in its content was noticed in leaves. In both roots and leaves, non-protein thiol content was found to increase except at higher metal concentrations at 72 h. The data of proline content have shown significant (p<0.01) increase at 40 microM onwards in both part of the plants after 48 and 72 h. Correlation coefficient was evaluated between metal accumulations with various parameters and also between different antioxidant parameters with MDA. Since the level of bacoside-A (active constituent) content in metal treated plants increases, therefore, it is advisable to assess the biological activity of the plants before using for medicinal purposes, particularly in developing countries.

Response of stress indicators and growth parameters of Tibouchina pulchra Cogn. exposed to air and soil pollution near the industrial complex of Cubatão, Brazil.

PubMed

Klumpp, G; Furlan, C M; Domingos, M; Klumpp, A

2000-01-31

The present study was performed in the vicinity of the industrial complex of Cubatão, São Paulo, Brazil, in order to evaluate the response of 'manaca da serra' Tibouchina pulchra Cogn. (Melastomataceae), a common species of secondary Atlantic Rain Forest vegetation, to the impact of complex air pollution. Emphasis was given to changes of biochemical parameters such as ascorbic acid concentration, peroxidase activity, contents of water-soluble thiols, pH of leaf extract and buffering capacity. These plant factors are often used as early indicators of air pollution stress. Field experiments included sampling of leaves from mature trees in areas with different air pollution load (passive monitoring), exposure of saplings cultivated in uniform soil at these areas (active monitoring) and a study on the combined effects of contaminated soil and air pollution. In general, metabolic response of saplings was more accentuated than that of mature trees. Leaf extract pH and buffering capacity showed no or only small alterations in plants exposed to industrial emissions. In contrast, air pollution resulted in a distinct decrease in ascorbic acid contents and an increase in peroxidase activity and thiol concentrations in leaves. Cultivation of saplings in soil types from contaminated regions frequently caused the same modifications or enhanced the effects produced by air pollution. Growth analysis of exposed saplings demonstrated that a change of the relationship between above-ground and below-ground plant parts was the most obvious effect of air pollution and soil contamination. The experiments showed that even T. pulchra, a species considered resistant to air pollution, suffers metabolic disturbances by the present ambient air and soil quality. Although biochemical and physiological alterations were not related to a certain air pollution type, they could be used to estimate the overall pollution load and to map zones with different air quality.

Screening and identification of resistance related proteins from apple leaves inoculated with Marssonina coronaria (EII. & J. J. Davis)

PubMed Central

2014-01-01

Background Apple, an invaluable fruit crop worldwide, is often prone to infection by pathogenic fungi. Identification of potentially resistance-conferring apple proteins is one of the most important aims for studying apple resistance mechanisms and promoting the development of disease-resistant apple strains. In order to find proteins which promote resistance to Marssonina coronaria, a deadly pathogen which has been related to premature apple maturation, proteomes from apple leaves inoculated with M. coronaria were characterized at 3 and 6 days post-inoculation by two dimensional electrophoresis (2-DE). Results Overall, 59 differentially accumulated protein spots between inoculation and non-inoculation were successfully identified and aligned as 35 different proteins or protein families which involved in photosynthesis, amino acid metabolism, transport, energy metabolism, carbohydrate metabolism, binding, antioxidant, defense and stress. Quantitative real-time PCR (qRT-PCR) was also used to examine the change of some defense and stress related genes abundance under inoculated conditions. Conclusions In a conclusion, different proteins in response to Marssonina coronaria were identified by proteomic analysis. Among of these proteins, there are some PR proteins, for example class III endo-chitinase, beta-1,3-glucanase and thaumatine-like protein, and some antioxidant related proteins including aldo/keto reductase AKR, ascorbate peroxidase and phi class glutathione S-transferase protein that were associated with disease resistance. The transcription levels of class III endo-chitinase (L13) and beta-1, 3-glucanase (L17) have a good relation with the abundance of the encoded protein’s accumulation, however, the mRNA abundance of thaumatine-like protein (L22) and ascorbate peroxidase (L28) are not correlated with their protein abundance of encoded protein. To elucidate the resistant mechanism, the data in the present study will promote us to investigate further the expression regulation of these target proteins. PMID:24507458

Fibre elongation requires normal redox homeostasis modulated by cytosolic ascorbate peroxidase in cotton (Gossypium hirsutum).

PubMed

Guo, Kai; Du, Xueqiong; Tu, Lili; Tang, Wenxin; Wang, Pengcheng; Wang, Maojun; Liu, Zhen; Zhang, Xianlong

2016-05-01

High-quality cotton fibre equates to a more comfortable textile. Fibre length is an important index of fibre quality. Hydrogen peroxide (H2O2) acts as a signalling molecule in the regulation of fibre elongation. Results from in vitro ovule culture suggest that the alteration of fibre cell H2O2 levels affects fibre development. Ascorbate peroxidase (APX) is an important reactive oxygen species (ROS) scavenging enzyme, and we found that GhAPX1AT/DT encoded one member of the previously unrealized group of cytosolic APXs (cAPXs) that were preferentially expressed during the fibre elongation stage. Transgenic cottons with up- and down-regulation of GhAPX1AT/DT were generated to control fibre endogenous levels of H2O2 Suppression of all cAPX (IAO) resulted in a 3.5-fold increase in H2O2 level in fibres and oxidative stress, which significantly suppressed fibre elongation. The fibre length of transgenic lines with over-expression or specific down-regulation of GhAPX1AT/DT did not show any obvious change. However, the fibres in the over-expression lines exhibited higher tolerance to oxidative stress. Differentially expressed genes (DEGs) in fibres at 10 days post-anthesis (DPA) of IAO lines identified by RNA-seq were related to redox homeostasis, signalling pathways, stress responses and cell wall synthesis, and the DEGs that were up-regulated in IAO lines were also up-regulated in the 10 DPA and 20 DPA fibres of wild cotton compared with domesticated cotton. These results suggest that optimal H2O2 levels and redox state regulated by cytosolic APX are key mechanisms regulating fibre elongation, and dysregulation of the increase in H2O2 induces oxidative stress and results in shorter fibres by initiating secondary cell wall-related gene expression. © The Author 2016. Published by Oxford University Press on behalf of the Society for Experimental Biology.

Peroxisomal Ascorbate Peroxidase Resides within a Subdomain of Rough Endoplasmic Reticulum in Wild-Type Arabidopsis Cells1

PubMed Central

Lisenbee, Cayle S.; Heinze, Michael; Trelease, Richard N.

2003-01-01

Previously we reported (R.T. Mullen, C.S. Lisenbee, J.A. Miernyk, R.N. Trelease [1999] Plant Cell 11: 2167–2185) that overexpressed ascorbate peroxidase (APX), a peroxisomal membrane protein, sorted indirectly to Bright Yellow-2 cell peroxisomes via a subdomain of the endoplasmic reticulum (ER; peroxisomal endoplasmic reticulum [pER]). More recently, a pER-like compartment also was identified in pumpkin (Cucurbita pepo) and transformed Arabidopsis cells (K. Nito, K. Yamaguchi, M. Kondo, M. Hayashi, M. Nishimura [2001] Plant Cell Physiol 42: 20–27). Here, we characterize more extensively the localization of endogenous Arabidopsis peroxisomal APX (AtAPX) in cultured wild-type Arabidopsis cells (Arabidopsis var. Landsberg erecta). AtAPX was detected in peroxisomes, but not in an ER subcompartment, using immunofluorescence microscopy. However, AtAPX was detected readily with immunoblots in both peroxisomal and ER fractions recovered from sucrose (Suc) density gradients. Most AtAPX in microsomes (200,000g, 1 h pellet) applied to gradients exhibited a Mg2+-induced shift from a distribution throughout gradients (approximately 18%–40% [w/w] Suc) to ≥42% (w/w) Suc regions of gradients, including pellets, indicative of localization in rough ER vesicles. Immunogold electron microscopy of the latter fractions verified these findings. Further analyses of peroxisomal and rough ER vesicle fractions revealed that AtAPX in both fractions was similarly associated with and located mostly on the cytosolic face of the membranes. Thus, at the steady state, endogenous peroxisomal AtAPX resides at different levels in rough ER and peroxisomes. Collectively, these findings show that rather than being a transiently induced sorting compartment formed in response to overexpressed peroxisomal APX, portions of rough ER (pER) in wild-type cells serve as a constitutive sorting compartment likely involved in posttranslational routing of constitutively synthesized peroxisomal APX. PMID:12805617

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

PubMed Central

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

2015-01-01

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. PMID:26649488

Ascorbic Acid Metabolism in Pea Seedlings. A Comparison of d-Glucosone, l-Sorbosone, and l-Galactono-1,4-Lactone as Ascorbate Precursors1

PubMed Central

Pallanca, Jane E.; Smirnoff, Nicholas

1999-01-01

l-Ascorbic acid (AsA) accumulates in pea (Pisum sativum L.) seedlings during germination, with the most rapid phase of accumulation coinciding with radicle emergence. Monodehydroascorbate reductase and dehydroascorbic acid reductase were active in the embryonic axes before AsA accumulation started, whereas AsA oxidase and AsA peroxidase activities increased in parallel with AsA. Excised embryonic axes were used to investigate the osone pathway of AsA biosynthesis, in which d-glucosone and l-sorbosone are the proposed intermediates. [U-14C]Glucosone was incorporated into AsA and inhibited the incorporation of [U-14C]glucose (Glc) into AsA. A higher d-glucosone concentration (5 mm) inhibited AsA accumulation. l-Sorbosone did not affect AsA pool size but caused a small inhibition in the incorporation of [U-14C]Glc into AsA. Oxidase and dehydrogenase activities capable of converting Glc or Glc-6-phosphate to glucosone were not detected in embryonic axis extracts. The osones are therefore unlikely to be physiological intermediates of AsA biosynthesis. l-Galactono-1,4-lactone, recently proposed as the AsA precursor (G.L. Wheeler, M.A. Jones, N. Smirnoff [1998] Nature 393: 365–369), was readily converted to AsA by pea embryonic axes. Although l-galactono-1,4-lactone did not inhibit [14C]Glc incorporation into AsA, this does not mean that it is not a precursor, because competition between endogenous and exogenous pools was minimized by its very small pool size and rapid metabolism. PMID:10364396

Heterologous expression of the Pleurotus ostreatus MnP3 gene by the laccase gene promoter in Lentinula edodes.

PubMed

Sato, Toshitsugu; Irie, Toshikazu; Yoshino, Fumihiko

2017-08-01

Lentinula edodes (shiitake), which have a powerful ligninolytic system, is one of the most important edible mushrooms in Asia. In this study, we introduced the manganese peroxidase (MnP, EC 1.11.1.13) gene from Pleurotus ostreatus driven by L. edodes laccase 1 gene promoter into L. edodes for expression. The resulting transformant expressed the recombinant gene and showed a higher level of MnP activity than that of the wild-type strain.

[Effects of calcium and ABA on photosynthesis and related enzymes activities in cucumber seedlings under drought stress].

PubMed

Chen, Lu Lu; Wang, Xiu Feng; Liu, Mei; Yang, Feng Juan; Shi, Qing Hua; Wei, Min; Li, Qing Ming

2016-12-01

To investigate the effect of calcium and ABA on photosynthesis and the activities of antioxidant enzymes in cucumber seedlings under drought stress, the cucumber was used as the expe-riment materials, normal nutrient solution culture was considered as the control, and PEG-6000 application in the nutrient solution simulated the drought stress. There were five different treatments which were spraying water, ABA, CaCl 2 +ABA, LaCl 3 (calcium channel inhibitor)+ABA and EGTA (calcium ion chelating agent)+ABA under drought stress. The results showed that drought stress inhibited the growth of cucumber seedlings, and reduced the activities of antioxidant enzymes, nitrate reductase, net photosynthetic rate and fluorescence parameters of the cucumber seedlings leaves. The application of ABA reduced the inhibition of activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT) and ascorbate peroxidase (APX), photosynthesis (P n , g s ) and the fluorescence parameters (F v '/F m ', q P and ETR), and decreased the damage of drought stress on plant. Spraying CaCl 2 +ABAsignificantly promoted the positive effect of ABA, while EGTA+ABA and LaCl 3 +ABA didn't show the promoting effect.

Salicylic acid and calcium-induced protection of wheat against salinity.

PubMed

Al-Whaibi, Mohamed H; Siddiqui, Manzer H; Basalah, Mohammed O

2012-07-01

Soil salinity is one of the important environmental factors that produce serious agricultural problems. The objective of the present study was to determine the interactive effect of salicylic acid (SA) and calcium (Ca) on plant growth, photosynthetic pigments, proline (Pro) concentration, carbonic anhydrase (CA) activity and activities of antioxidant enzymes of Triticum aestivum L. (cv. Samma) under salt stress. Application of 90 mM of NaCl reduced plant growth (plant height, fresh weight (FW) and dry weight (DW), chlorophyll (Chl) a, Chl b, CA activity) and enhanced malondialdehyde (MDA) and Pro concentration. However, the application of SA or Ca alone as well as in combination markedly improved plant growth, photosynthetic pigments, Pro concentration, CA activity and activities of antioxidant enzymes peroxidase (POD), catalase (CAT), superoxide dismutase (SOD), glutathione reductase (GR) and ascorbate peroxidase (APX) under salt stress. It was, therefore, concluded that application of SA and Ca alone as well as in combination ameliorated the adverse effect of salinity, while combined application proved more effective to reduce the oxidative stress generated by NaCl through reduced MDA accumulation, Chl a/b ratio and Chls degradation and enhanced activities of antioxidant enzymes.

Overexpression of MpCYS4, a phytocystatin gene from Malus prunifolia (Willd.) Borkh., delays natural and stress-induced leaf senescence in apple.

PubMed

Tan, Yanxiao; Yang, Yingli; Li, Chao; Liang, Bowen; Li, Mingjun; Ma, Fengwang

2017-06-01

Phytocystatins are a well-characterized class of naturally occurring protease inhibitors that prevent the catalysis of papain-like cysteine proteases. The action of cystatins in stress tolerance has been studied intensively, but relatively little is known about their functions in plants during leaf senescence. Here, we examined the potential roles of the apple cystatin, MpCYS4, in leaf photosynthesis as well as the concentrations and composition of leaf proteins when plants encounter natural or stress-induced senescence. Overexpression of this gene in apple rootstock M26 effectively slowed the senescence-related declines in photosynthetic activity and chlorophyll concentrations and prevented the action of cysteine proteinases during the process of degrading proteins (e.g., Rubisco) in senescing leaves. Moreover, MpCYS4 alleviated the associated oxidative damage and enhanced the capacity of plants to eliminate reactive oxygen species by activating antioxidant enzymes such as ascorbate peroxidase, peroxidase, and catalase. Consequently, plant cells were protected against damage from free radicals during leaf senescence. Based on these results, we conclude that MpCYS4 functions in delaying natural and stress-induced senescence of apple leaves. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

PGPR strain Paenibacillus polymyxa SQR-21 potentially benefits watermelon growth by re-shaping root protein expression.

PubMed

E, Yaoyao; Yuan, Jun; Yang, Fang; Wang, Lei; Ma, Jinghua; Li, Jing; Pu, Xiaowei; Raza, Waseem; Huang, Qiwei; Shen, Qirong

2017-12-01

Paenibacillus polymyxa (SQR-21) is not only a plant growth-promoting rhizobacteria, but also an effective biocontrol agent against Fusarium wilt disease of watermelon. For the better understanding and clarifying the potential mechanisms of SQR-21 to improve watermelon growth and disease resistance, a split-root methodology in hydroponic and LC-MS technology with the label free method was used to analyze the key root proteins involved in watermelon metabolism and disease resistance after the inoculation of SQR-21. Out of 623 identified proteins, 119 proteins were differentially expressed when treatment (SQR-21 inoculation) and control (no bacterial inoculation) were compared. Among those, 57 and 62 proteins were up-regulated and down-regulated, respectively. These differentially expressed proteins were identified to be involved in signal transduction (ADP-ribosylation factor, phospholipase D), transport (aspartate amino-transferase), carbohydratemetabolic (glucose-6-phosphate dehydrogenase, UDP-glucose pyrophosphorylase), defense and response to stress (glutathione S-transferase, Ubiquitin-activating enzyme E1), and oxidation-reduction process (thioredoxin peroxidase, ascorbate peroxidase). The results of this study indicated that SQR-21 inoculation on the watermelon roots benefits plant by inducing the expression of several proteins involved in growth, photosynthesis, and other metabolic and physiological activities.

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

PubMed

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.

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

PubMed

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.

Variability of phenolic content and antioxidant activity of two lettuce varieties under Fe deficiency.

PubMed

Msilini, Najoua; Oueslati, Samia; Amdouni, Thouraya; Chebbi, Mohamed; Ksouri, Riadh; Lachaâl, Mokhtar; Ouerghi, Zeineb

2013-06-01

Fe deficiency affects food growth and quality in calcareous soils. In this study, the effect of Fe deficiency on growth parameters, phenolic content and antioxidant capacities of two lettuce shoots varieties (Romaine and Vista) were investigated. Fresh matter production, pigment (chlorophyll and carotenoid) and Fe2+ content were significantly reduced by Fe deficiency in both varieties. However, restriction of these parameters was particularly pronounced in Romaine variety as compared to Vista. Moreover, Fe deficiency caused decreases in the activity of antioxidant enzymes such as catalase and guaiacol peroxidase, whereas ascorbate peroxidase and malondialdehyde concentrations were not significantly affected. On the other hand, Fe deficiency in Vista variety induced an increase in polyphenol and flavonoid content as compared to Romaine variety. In addition, total antioxidant capacity and antiradical test against DPPH radical decreased in leaves of Romaine variety after 15 days of treatment. These results suggest that the higher polyphenol content in Vista variety supports the involvement of these components in the stability of antioxidant capacities and then in its protection against oxidative damage generated by Fe deficiency in lettuce plants. © 2012 Society of Chemical Industry.

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

PubMed

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.

Antioxidative effect of melatonin, ascorbic acid and N-acetylcysteine on caerulein-induced pancreatitis and associated liver injury in rats

PubMed Central

Eşrefoğlu, Mukaddes; Gül, Mehmet; Ateş, Burhan; Batçıoğlu, Kadir; Selimoğlu, Mukadder Ayşe

2006-01-01

AIM: To investigate the role of oxidative injury in pancreatitis-induced hepatic damage and the effect of antioxidant agents such as melatonin, ascorbic acid and N-acetyl cysteine on caerulein-induced pancreatitis and associated liver injury in rats. METHODS: Thirty-eight female Wistar rats were used. Acute pancreatitis (AP) was induced by two i.p. injections of caerulein at 2-h intervals (at a total dose of 100 µg/kg b.wt). The other two groups received additional melatonin (20 mg/kg b.wt) or an antioxidant mixture containing L(+)-ascorbic acid (14.3 mg/kb.wt.) and N-acetyl cysteine (181 mg/kg b.wt.) i.p. shortly before each injection of caerulein. The rats were sacrificed by decapitation 12 h after the last injection of caerulein. Pancreatic and hepatic oxidative stress markers were evaluated by changes in the amount of lipid peroxides measured as malondialdehyde (MDA) and changes in tissue antioxidant enzyme levels, catalase (CAT) and glutathione peroxidase (GPx). Histopathological examination was performed using scoring systems. RESULTS: The degree of hepatic cell degeneration, intracellular vacuolization, vascular congestion, sinusoidal dilatation and inflammatory infiltration showed a significant difference between caerulein and caerulein + melatonin (P  = 0.001), and careulein and caerulein + L(+)-ascorbic acid + N-acetyl cysteine groups (P  = 0.002). The degree of aciner cell degeneration, pancreatic edema, intracellular vacuolization and inflammatory infiltration showed a significant difference between caerulein and caerulein + melatonin (P  = 0.004), and careulein and caerulein + L(+)-ascorbic acid + N-acetyl cysteine groups (P = 0.002). Caerulein-induced pancreatic and liver damage was accompanied with a significant increase in tissue MDA levels (P  = 0.01, P  = 0.003, respectively) whereas a significant decrease in CAT (P  = 0.002, P = 0.003, respectively) and GPx activities (P  = 0.002, P  = 0.03, respectively). Melatonin and L(+)-ascorbic acid + N-acetyl cysteine administration significantly decreased MDA levels in pancreas (P  = 0.03, P  = 0.002, respectively) and liver (P  = 0.007, P  = 0.01, respectively). Administration of these agents increased pancreatic and hepatic CAT and GPx activities. Melatonin significantly increased pancreatic and hepatic CAT (P  = 0.002, P  = 0.001, respectively) and GPx activities (P  = 0.002, P  = 0.001). Additionally, L(+)-ascorbic acid+N-acetyl cysteine significantly increased pancreatic GPx (P  = 0.002) and hepatic CAT and GPx activities (P  = 0.001, P  = 0.007, respectively) CONCLUSION: Oxidative injury plays an important role not only in the pathogenesis of AP but also in pancreatitis-induced hepatic damage. Antioxidant agents such as melatonin and ascorbic acid + N-acetyl cysteine, are capable of limiting pancreatic and hepatic damage produced during AP via restoring tissue antioxidant enzyme activities. PMID:16482627

Phytochemical investigations and antioxidant potential of roots of Leea macrophylla (Roxb.).

PubMed

Mahmud, Zobaer Al; Bachar, Sitesh C; Hasan, Choudhury Mahmood; Emran, Talha Bin; Qais, Nazmul; Uddin, Mir Muhammad Nasir

2017-07-06

Oleanolic acid (NZ-15), 7 α, 28-olean diol (NZ-38) and Stigmasterol (NZ-14) were isolated from the ethanolic extracts of the roots of Leea macrophylla (Family: Leeaceae) by using chromatographic analysis. This is the first report of isolation of these compounds from this plant. Their structures were constructed by spectroscopic analysis and by comparing the data with the published one. Subsequently the ethanolic extract was fractionated with two organic solvents and all the fractions were studied to evaluate their in vitro antioxidant property. The ethanolic extract was fractionated with two organic solvents and all the fractions were studied to evaluate their in vitro antioxidant property by DPPH free radical scavenging assay, superoxide anion radical scavenging assay, nitric oxide radical scavenging assay, and reducing power assay. In the DPPH free radical scavenging assay and superoxide radical scavenging assay, the ethyl acetate soluble fraction of ethanolic extract revealed the highest free radical scavenging activity with IC 50 value of 2.65 and 155.62 μg/ml, respectively as compared to standard ascorbic acid (IC 50 value of 5.8 and 99.66 μg/ml). Ethyl acetate fraction also possessed highest reducing power activity with an EC50 value of 15.27 μg/ml compared to ascorbic acid (EC 50 0.91 μg/ml). On the other hand, the carbon tetrachloride fraction exhibited most significant NO scavenging activity with IC 50 value of 277.8 μg/ml that was even higher than that of standard ascorbic acid (IC 50 value 356.04 μg/ml). In addition, the total phenolic contents of these extract and fractions were evaluated using Folin-Ciocalteu reagent and varied from 7.93 to 50.21 mg/g dry weight expressed as gallic acid equivalents (GAE). This study showed that different extracts of roots of L. macrophylla possess potential DPPH, superoxide, and NO free radical scavenging activities. The antioxidant activities of the plant extracts might be due to the presence of oleanolic acid, oleanolic acid derivative 7 α, 28-olean diol and stigmasterol.

Plant-derived micronutrients suppress monocyte adhesion to cultured human aortic endothelial cell layer by modulating its extracellular matrix composition.

PubMed

Ivanov, Vadim; Ivanova, Svetlana; Kalinovsky, Tatiana; Niedzwiecki, Aleksandra; Rath, Matthias

2008-07-01

Monocyte adhesion to endothelium plays an important role in atherosclerosis. We investigated the effects of micronutrients on monocyte-binding properties of extracellular matrix (ECM) produced by human aortic endothelial cells (AoEC). Confluent cultures of AoEC were exposed to ascorbic acid, quercetin, gotu kola extract (10% asiatic acid), green tea extract (40% epigallocatechin gallate), or a mixture of these micronutrients for 48 hours. AoEC-produced ECM was exposed by differential treatment. U937 monocyte adhesion was assayed by fluorescence. ECM composition was assayed immunochemically and with radiolabeled metabolic precursors. AoEC exposure to micronutrients reduced ECM capacity to bind monocytes in a dose-dependent manner. This effect was accompanied by profound changes in the ECM composition. Correlation analysis revealed that changes in monocyte adhesion to ECM had the strongest positive correlation with ECM content for laminin (CC = 0.9681, P < 0.01), followed by fibronectin, collagens type III, I, and IV, biglycan, heparan sulfate, and elastin. The strongest negative correlation was with chondroitin sulfate (CC = -0.9623, P < 0.01), followed by perlecan and versican. Individual micronutrients had diverse effects on ECM composition and binding properties, and their mixture was the most effective treatment. In conclusion, micronutrient-dependent reduction of monocyte adhesion to endothelium is partly mediated through specific modulation of ECM composition and properties.

Oxidative stress biomarkers in Senegal sole, Solea senegalensis, to assess the impact of heavy metal pollution in a Huelva estuary (SW Spain): seasonal and spatial variation.

PubMed

Oliva, Milagrosa; José Vicente, Juan; Gravato, Carlos; Guilhermino, Lucia; Dolores Galindo-Riaño, María

2012-01-01

The response of wild fish to heavy metals was studied in sole (Solea senegalensis) collected in 2004, 2005 and 2006 at three sampling sites from Huelva estuary (SW Spain), in the vicinity of a petrochemical and mining industry. Heavy metals As, Cd, Cu, Fe, Pb and Zn were analyzed in samples collected from sediment, water and tissue (liver) to examine their bioconcentration and effects in fish such as lipid peroxidation (LPO), catalase (CAT; EC 1.11.1.6), glutathione peroxidase (GPx; EC 1.8.1.7), glutathione S-transferase (GST; EC 2.5.1.18) and glutathione reductase (GR; EC 1.11.1.6) were also analyzed in the fish liver. The results showed different effects in sole from diverse locations with varying degrees of pollution. Significant differences in LPO, CAT and GR activities between control fish and fish from sampling sites were observed as well as seasonal differences for biomarkers. Significant correlations were established between some biomarkers and heavy metals concentrations in liver, sediment and water. This study indicates the usefulness of integrating a set of biomarkers to assess the effects of pollutants in aquatic environments under complex mix of pollutants and chronic pollution situation. Copyright © 2011 Elsevier Inc. All rights reserved.

Correlative light and electron microscopic detection of GFP-labeled proteins using modular APEX.

PubMed

Ariotti, Nicholas; Hall, Thomas E; Parton, Robert G

2017-01-01

The use of green fluorescent protein (GFP) and related proteins has revolutionized light microscopy. Here we describe a rapid and simple method to localize GFP-tagged proteins in cells and in tissues by electron microscopy (EM) using a modular approach involving a small GFP-binding peptide (GBP) fused to the ascorbate peroxidase-derived APEX2 tag. We provide a method for visualizing GFP-tagged proteins by light and EM in cultured cells and in the zebrafish using modular APEX-GBP. Furthermore, we describe in detail the benefits of this technique over many of the currently available correlative light and electron microscopy approaches and demonstrate APEX-GBP is readily applicable to modern three-dimensional techniques. Copyright © 2017 Elsevier Inc. All rights reserved.

Activation of immunity, immune response, antioxidant ability, and resistance against Vibrio alginolyticus in white shrimp Litopenaeus vannamei decrease under long-term culture at low pH.

PubMed

Chen, Yu-Yuan; Chen, Jiann-Chu; Tseng, Kuei-Chi; Lin, Yong-Chin; Huang, Chien-Lun

2015-10-01

The growth, activation of immunity, immune parameters, and transcript levels of cytMnSOD, mtMnSOD, ecCuZnSOD, glutathione peroxidase (GPx), catalase, lysozyme, and penaeidin 3a were examined in white shrimp Litopenaeus vannamei reared at pH 6.8 and 8.1 after 24 weeks. No significant difference in growth was observed between the two groups. An in vitro study indicated that phenoloxidase activity and respiratory bursts (RB, release of the superoxide anion) were significantly higher in the haemocytes of pH 8.1 shrimp (shrimp reared at pH 8.1) than in pH 6.8 shrimp (shrimp reared at pH 6.8). An in vivo study indicated that the levels of immune parameters of pH 8.1 shrimp were significantly higher than in pH 6.8 shrimp, and the transcript levels of cytMnSOD, ecCuZnSOD, glutathione peroxidase, lysozyme, and penaeidin 3a were down-regulated in pH 6.8 shrimp. In another experiment, shrimp reared at pH 6.8 and 8.1 for 24 weeks were challenged with Vibrio alginolyticus. The mortality rate of pH 6.8 shrimp was significantly higher than in pH 8.1 shrimp over 12-168 h. Phagocytic activity, phagocytic index, and clearance efficiency to V. alginolyticus were significantly lower in pH 6.8 shrimp. We concluded that shrimp under long-term culture at pH 6.8 exhibited decreased resistance against V. alginolyticus as evidenced by reductions in the activation of immunity and immune parameters together with decreased transcript levels of cytMnSOD, ecCuZnSOD, GPx, lysozyme, and penaeidin 3a. Copyright © 2015 Elsevier Ltd. All rights reserved.

Comparison of the phytoremediation potentials of Medicago falcata L. And Medicago sativa L. in aged oil-sludge-contaminated soil.

PubMed

Panchenko, Leonid; Muratova, Anna; Turkovskaya, Olga

2017-01-01

Thirteen-year monitoring of the vegetation growing in the industrial and adjacent areas of an oil refinery showed the prevalence of yellow medick (Medicago falcata L.) over other plant species, including alfalfa (Medicago sativa L.). A comparative field study of the two Medicago species established that yellow medick and alfalfa exhibited similar resistance to soil petroleum hydrocarbons and that the pollutant concentration in their rhizosphere was 30% lower than that in the surrounding bulk soil. In laboratory pot experiments, yellow medick reduced the contaminant content by 18% owing to the degradation of the major heavy oil fractions, such as paraffins, naphthenes, and alcohol and benzene tars; and it was more successful than alfalfa. Both species were equally effective in stimulating the total number of soil microorganisms, but the number of hydrocarbon-oxidizing microorganisms, including polycyclic aromatic hydrocarbon degraders, was larger in the root zone of alfalfa. In turn, yellow medick provided a favorable balance of available nitrogen. Both Medicago species equally stimulated the dehydrogenase and peroxidase activities of the soil, and yellow medick increased the activity of soil polyphenol oxidase but reduced the activity of catalase. The root tissue activity of catalase, ascorbate oxidase, and tyrosinase was grater in alfalfa than in yellow medick. The peroxidase activity of plant roots was similar in both species, but nondenaturing polyacrylamide gel electrophoresis showed some differences in the peroxidase profiles of the root extracts of alfalfa and yellow medick. Overall, this study suggests that the phytoremediation potentials of yellow medick and alfalfa are similar, with some differences.

Inhibitory effect on activator protein-1, nuclear factor-kappaB, and cell transformation by extracts of strawberries (Fragaria x ananassa Duch.).

PubMed

Wang, Shiow Y; Feng, Rentian; Lu, Yongju; Bowman, Linda; Ding, Min

2005-05-18

The inhibitory effects of strawberry (Fragaria x ananassa Duch.) antioxidant enzymes on tetradecanoylphorbol-13-acetate (TPA) or ultraviolet-B (UVB) induced activator protein-1 (AP-1) and nuclear factor-kappaB (NF-kappaB) were studied. The inhibitory effects of strawberry extracts on the proliferation and transformation of human and mouse cancer cells were also evaluated. Strawberries had high activities of glutathione peroxidase, superoxide dismutase, guaiacol peroxidase, ascorbate peroxidase, and glutathione reductase. Strawberry extracts inhibited the proliferation of human lung epithelial cancer cell line A549 and decreased TPA-induced neoplastic transformation of JB6 P+ mouse epidermal cells. Pretreatment of JB6 P+ mouse epidermal cells with strawberry extract resulted in the inhibition of both UVB- and TPA-induced AP-1 and NF-kappaB transactivation. Furthermore, strawberry extract also blocked TPA-induced phosphorylation of extracellular signal-regulated kinases (ERKs) and UVB-induced phosphorylation of ERKs and JNK kinase in JB6 P+ mouse epidermal cell culture. These results suggest that the ability of strawberries to block UVB- and TPA-induced AP-1 and NF-kappaB activation may be due to their antioxidant properties and their ability to reduce oxidative stress. The oxidative events that regulate AP-1 and NF-kappaB transactivation can be important molecular targets for cancer prevention. The strawberries may be highly effective as a chemopreventive agent that acts by targeting the down-regulation of AP-1 and NF-kappaB activities, blocking MAPK signaling, and suppressing cancer cell proliferation and transformation.

Synthesis and antioxidant evaluation of (S,S)- and (R,R)-secoisolariciresinol diglucosides (SDGs).

PubMed

Mishra, Om P; Simmons, Nicholas; Tyagi, Sonia; Pietrofesa, Ralph; Shuvaev, Vladimir V; Valiulin, Roman A; Heretsch, Philipp; Nicolaou, K C; Christofidou-Solomidou, Melpo

2013-10-01

Secoisolariciresinol diglucosides (SDGs) (S,S)-SDG-1 (major isomer in flaxseed) and (R,R)-SDG-2 (minor isomer in flaxseed) were synthesized from vanillin via secoisolariciresinol (6) and glucosyl donor 7 through a concise route that involved chromatographic separation of diastereomeric diglucoside derivatives (S,S)-8 and (R,R)-9. Synthetic (S,S)-SDG-1 and (R,R)-SDG-2 exhibited potent antioxidant properties (EC50=292.17±27.71 μM and 331.94±21.21 μM, respectively), which compared well with that of natural (S,S)-SDG-1 (EC50=275.24±13.15 μM). These values are significantly lower than those of ascorbic acid (EC50=1129.32±88.79 μM) and α-tocopherol (EC50=944.62±148.00 μM). Compounds (S,S)-SDG-1 and (R,R)-SDG-2 also demonstrated powerful scavenging activities against hydroxyl [natural (S,S)-SDG-1: 3.68±0.27; synthetic (S,S)-SDG-1: 2.09±0.16; synthetic (R,R)-SDG-2: 1.96±0.27], peroxyl [natural (S,S)-SDG-1: 2.55±0.11; synthetic (S,S)-SDG-1: 2.20±0.10; synthetic (R,R)-SDG-2: 3.03±0.04] and DPPH [natural (S,S)-SDG-1: EC50=83.94±2.80 μM; synthetic (S,S)-SDG-1: EC50=157.54±21.30 μM; synthetic (R,R)-SDG-2: EC50=123.63±8.67 μM] radicals. These results confirm previous studies with naturally occurring (S,S)-SDG-1 and establish both (S,S)-SDG-1 and (R,R)-SDG-2 as potent antioxidants and free radical scavengers for potential in vivo use. Copyright © 2013 Elsevier Ltd. All rights reserved.

Changes in rubisco, cysteine-rich proteins and antioxidant system of spinach (Spinacia oleracea L.) due to sulphur deficiency, cadmium stress and their combination.

PubMed

Bagheri, Rita; Ahmad, Javed; Bashir, Humayra; Iqbal, Muhammad; Qureshi, M Irfan

2017-03-01

Sulphur (S) deficiency, cadmium (Cd) toxicity and their combinations are of wide occurrence throughout agricultural lands. We assessed the impact of short-term (2 days) and long-term (4 days) applications of cadmium (40 μg/g soil) on spinach plants grown on sulphur-sufficient (300 μM SO 4 2- ) and sulphur-deficient (30 μM SO 4 2- ) soils. Compared with the control (+S and -Cd), oxidative stress was increased by S deficiency (-S and -Cd), cadmium (+S and +Cd) and their combination stress (-S and +Cd) in the order of (S deficiency) < (Cd stress) < (S deficiency and +Cd stress). SDS-PAGE profile of leaf proteins showed a high vulnerability of rubisco large subunit (RbcL) to S deficiency. Rubisco small subunit (RbcS) was particularly sensitive to Cd as well as dual stress (+Cd and -S) but increased with Cd in the presence of S. Cysteine content in low molecular weight proteins/peptide was also affected, showing a significant increase under cadmium treatment. Components of ascorbate-glutathione antioxidant system altered their levels, showing the maximum decline in ascorbate (ASA), dehydroascorbate (DHA), total ascorbate (ASA + DHA, hereafter TA), glutathione (GSH) and total glutathione (GSH + GSSG, hereafter TG) under S deficiency. However, total ascorbate and total glutathione increased, besides a marginal increase in their reduced and oxidized forms, when Cd was applied in the presence of sufficient S. Sulphur supply also helped in increasing the activity of superoxide dismutase (SOD), ascorbate peroxidase (APX), glutathione reductase (GR) and catalase (CAT) under Cd stress. However, their activity suffered by S deficiency and by Cd stress during S deficiency. Each stress declined the contents of soluble protein and photosynthetic pigments; the highest decline in contents of protein and pigments occurred under S deficiency and dual stress respectively. The fresh and dry weights, although affected adversely by every stress, declined most under dual stress. It may be concluded that an optimal level of S is required during Cd stress for better response of SOD, APX, GR and CAT activity, as well as synthesis of cysteine. RbcS is as highly sensitive to S deficiency as RbcL is to Cd stress.

Overexpression of CaAPX Induces Orchestrated Reactive Oxygen Scavenging and Enhances Cold and Heat Tolerances in Tobacco

PubMed Central

Wang, Jiangying; Wu, Bin; Fan, Zhengqi; Li, Xinlei; Ni, Sui

2017-01-01

Ascorbate peroxidase (APX) acts indispensably in synthesizing L-ascorbate (AsA) which is pivotal to plant stress tolerance by detoxifying reactive oxygen species (ROS). Enhanced activity of APX has been shown to be a key step for genetic engineering of improving plant tolerance. However it needs a deeper understanding on the maintenance of cellular ROS homeostasis in response to stress. In this study, we identified and characterized an APX (CaAPX) gene from Camellia azalea. Quantitative real-time PCR (qRT-PCR) analysis showed that CaAPX was expressed in all tissues and peaked in immature green fruits; the expression levels were significantly upregulated upon cold and hot stresses. Transgenic plants displayed marked enhancements of tolerance under both cold and heat treatments, and plant growth was correlated with CaAPX expression levels. Furthermore, we monitored the activities of several ROS-scavenging enzymes including Cu/Zn-SOD, CAT, DHAR, and MDHAR, and we showed that stress tolerance was synchronized with elevated activities of ROS-scavenging. Moreover, gene expression analysis of ROS-scavenging enzymes revealed a role of CaAPX to orchestrate ROS signaling in response to temperature stresses. Overall, this study presents a comprehensive characterization of cellular response related to CaAPX expression and provides insights to breed crops with high temperature tolerances. PMID:28386551

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

NASA Astrophysics Data System (ADS)

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.

Metalaxyl Effects on Antioxidant Defenses in Leaves and Roots of Solanum nigrum L.

PubMed Central

de Sousa, Alexandra; AbdElgawad, Hamada; Asard, Han; Pinto, Ana; Soares, Cristiano; Branco-Neves, Simão; Braga, Teresa; Azenha, Manuel; Selim, Samy; Al Jaouni, Soad; Fidalgo, Fernanda; Teixeira, Jorge

2017-01-01

Overuse of pesticides has resulted in environmental problems, threating public health through accumulation in food chains. Phytoremediation is a powerful technique to clean up contaminated environments. However, it is necessary to unravel the metabolic mechanisms underlying phytoremediation in order to increase the efficiency of this process. Therefore, growth, physiological and biochemical responses in leaves and roots of Solanum nigrum L. exposed to the commonly used fungicide metalaxyl were investigated. This species shows characteristics that make it valuable as a potential tool for the remediation of organic pollutants. We found that once inside the plant, metalaxyl altered carbon metabolism, which resulted in a reduction of growth and lower biomass accumulation due to impairment of carbohydrate production (total soluble sugar, starch, rubisco) and increased photorespiration (glycolate oxidase, Gly/Ser ratio). A significant increase of antioxidant defenses (polyphenols, flavonoids, tocopherols, ascorbate, glutathione, superoxide dismutase, catalase, peroxidases, monodehydroascorbate- and dehydroascorbate reductase, gluthatione reductase) kept reactive oxygen species (ROS) levels under control (superoxide anion) leaving cell membranes undamaged. The results suggest that enhancing carbon assimilation and antioxidant capacity may be target parameters to improve this species’ phytoremediation capacities. Highlights • Metalaxyl inhibits growth by reducing photosynthesis and inducing photorespiration • Elevated antioxidant defenses protect metalaxyl-treated plants from oxidative damage • Ascorbate and glutathione are key antioxidants in metalaxyl tolerance. PMID:29250085

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

NASA Astrophysics Data System (ADS)

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.

Overexpression of CaAPX Induces Orchestrated Reactive Oxygen Scavenging and Enhances Cold and Heat Tolerances in Tobacco.

PubMed

Wang, Jiangying; Wu, Bin; Yin, Hengfu; Fan, Zhengqi; Li, Xinlei; Ni, Sui; He, Libo; Li, Jiyuan

2017-01-01

Ascorbate peroxidase (APX) acts indispensably in synthesizing L-ascorbate (AsA) which is pivotal to plant stress tolerance by detoxifying reactive oxygen species (ROS). Enhanced activity of APX has been shown to be a key step for genetic engineering of improving plant tolerance. However it needs a deeper understanding on the maintenance of cellular ROS homeostasis in response to stress. In this study, we identified and characterized an APX ( CaAPX ) gene from Camellia azalea . Quantitative real-time PCR (qRT-PCR) analysis showed that CaAPX was expressed in all tissues and peaked in immature green fruits; the expression levels were significantly upregulated upon cold and hot stresses. Transgenic plants displayed marked enhancements of tolerance under both cold and heat treatments, and plant growth was correlated with CaAPX expression levels. Furthermore, we monitored the activities of several ROS-scavenging enzymes including Cu/Zn-SOD , CAT , DHAR , and MDHAR , and we showed that stress tolerance was synchronized with elevated activities of ROS-scavenging. Moreover, gene expression analysis of ROS-scavenging enzymes revealed a role of CaAPX to orchestrate ROS signaling in response to temperature stresses. Overall, this study presents a comprehensive characterization of cellular response related to CaAPX expression and provides insights to breed crops with high temperature tolerances.

Function of antioxidant enzymes and metabolites during maturation of pea fruits

PubMed Central

Matamoros, Manuel A.; Loscos, Jorge; Dietz, Karl-Josef; Aparicio-Tejo, Pedro M.; Becana, Manuel

2010-01-01

In plant cells, antioxidants keep reactive oxygen species at low concentrations, avoiding oxidative damage while allowing them to play crucial functions in signal transduction. However, little is known about the role of antioxidants during fruit maturation, especially in legumes. Snap pea (Pisum sativum) plants, which have edible fruits, were grown under nodulating and non-nodulating conditions. Fruits were classified in three maturity stages and antioxidants were determined in the seeds and seedless pods. Maturation or prolonged storage of fruits at 25 °C led to a decline in antioxidant activities and metabolites and in γ-glutamylcysteine synthetase protein. Notable exceptions were superoxide dismutase activity and glutathione peroxidase protein, which increased in one or both of these processes. During maturation, cytosolic peroxiredoxin decreased in seeds but increased in pods, and ascorbate oxidase activity was largely reduced in seeds. In stored fruits, ascorbate oxidase activity was nearly abolished in seeds but doubled in pods. It is concluded that symbiotic nitrogen fixation is as effective as nitrogen fertilization in maintaining the antioxidant capacity of pea fruits and that, contrary to climacteric fruits, a general decrease in antioxidants during maturation does not involve oxidative stress. Results underscore the importance of the antioxidant system in reproductive organs and point to ascorbate–glutathione metabolism and cytosolic peroxiredoxin as key players in pea fruit development. PMID:19822534

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

PubMed

Asada, K

2000-10-29

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 ascorbate by reduced ferredoxin or catalysed by either dehydroascorbate reductase or monodehydroascorbate reductase. The water-water cycle therefore effectively shortens the lifetimes of photoproduced superoxide and hydrogen peroxide to suppress the production of hydroxyl radicals, their interactions with the target molecules in chloroplasts, and resulting photoinhibition. When leaves are exposed to photon intensities of sunlight in excess of that required to support the fixation of CO2, the intersystem electron carriers are over-reduced, resulting in photoinhibition. Under such conditions, the water-water cycle not only scavenges active oxygens, but also safely dissipates excess photon energy and electrons, in addition to downregulation of PS II and photorespiration. The dual functions of the water-water cycle for protection from photoinhibition under photon excess stress are discussed, along with its functional evolution.

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

PubMed

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.

Boron Nutrition of Tobacco BY-2 Cells. V. Oxidative Damage is the Major Cause of Cell Death Induced by Boron Deprivation

PubMed Central

Koshiba, Taichi; Kobayashi, Masaru; Matoh, Toru

2009-01-01

Boron (B) is an essential micronutrient for vascular plants. However, it remains unclear how B deficiency leads to various metabolic disorders and cell death. To understand this mechanism, we analyzed the physiological changes in suspension-cultured tobacco (Nicotiana tabacum) BY-2 cells upon B deprivation. When 3-day-old cells were transferred to B-free medium, cell death was detectable as early as 12 h after treatment. The B-deprived cells accumulated more reactive oxygen species and lipid peroxides than control cells, and showed a slight but significant decrease in the cellular ascorbate pool. Supplementing the media with lipophilic antioxidants effectively suppressed the death of B-deprived cells, suggesting that the oxidative damage is the immediate and major cause of cell death under B deficiency. Dead cells in B-free culture exhibited a characteristic morphology with a shrunken cytoplasm, which is often seen in cells undergoing programmed cell death (PCD). However, they did not display other hallmarks of PCD such as internucleosomal DNA fragmentation, decreased ascorbate peroxidase expression and protection from death by cycloheximide. These results suggest that the death of tobacco cells induced by B deprivation is not likely to be a typical PCD. PMID:19054807

Biochemical study of leaf browning in minimally processed leaves of lettuce (Lactuca sativa L. var. acephala).

PubMed

Degl'Innocenti, E; Guidi, L; Pardossi, A; Tognoni, F

2005-12-28

A series of biochemical parameters, including the concentration of total ascorbic acid (ASA(tot)) and the activities of phenylalanine ammonia lyase (PAL), polyphenol oxidase (PPO), and peroxidases (PODs), was investigated during cold storage (72 h at 4 degrees C in the dark) in fresh-cut (minimally processed) leaves of two lettuce (Lactuca sativa L. var. acephala) cultivars differing in the susceptibility to tissue browning: Green Salade Bowl (GSB), susceptible, and Red Salade Bowl (RSB), resistant. The two cultivars showed differences also at the biochemical level. The content in ASA(tot) increased in RSB, as a consequence of increased DHA concentration; conversely, ASA(tot) diminished in GSB, in which ASA was not detectable after 72 h of storage, thus suggesting a disappearance of ascorbate (both ASA and DHA) into nonactive forms. The antioxidant capacity (as determined by using FRAP analysis) decreased significantly during storage in RSB, while a strong increase was observed in GSB. PAL activity increased soon after processing reaching a maximum by 3 h, then it declined to a relatively constant value in RSB, while in GSB it showed a tendency to decrease in the first few hours from harvest and processing. POD activity, at least for chlorogenic acid, increased significantly during storage only in GSB.

Exogenous 5-aminolevulenic acid promotes seed germination in Elymus nutans against oxidative damage induced by cold stress.

PubMed

Fu, Juanjuan; Sun, Yongfang; Chu, Xitong; Xu, Yuefei; Hu, Tianming

2014-01-01

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.

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

PubMed

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.

Exogenous 5-Aminolevulenic Acid Promotes Seed Germination in Elymus nutans against Oxidative Damage Induced by Cold Stress

PubMed Central

Fu, Juanjuan; Sun, Yongfang; Chu, Xitong; Xu, Yuefei; Hu, Tianming

2014-01-01

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. PMID:25207651

Physicochemical and antioxidant properties of Algerian honey.

PubMed

Khalil, Ibrahim; Moniruzzaman, Mohammed; Boukraâ, Laïd; Benhanifia, Mokhtar; Islam, Asiful; Islam, Nazmul; Sulaiman, Siti Amrah; Gan, Siew Hua

2012-09-20

The aim of the present study was to characterize the physical, biochemical and antioxidant properties of Algerian honey samples (n = 4). Physical parameters, such as pH, moisture content, electrical conductivity (EC), total dissolved solids (TDS), color intensity, total sugar and sucrose content were measured. Several biochemical and antioxidant tests were performed to determine the antioxidant properties of the honey samples. The mean pH was 3.84 ± 0.01, and moisture the content was 13.21 ± 0.16%. The mean EC was 0.636 ± 0.001, and the mean TDS was 316.92 ± 0.92. The mean color was 120.58 ± 0.64 mm Pfund, and the mean 5-hydroxymethylfurfural (HMF) content was 21.49 mg/kg. The mean total sugar and reducing sugar contents were 67.03 ± 0.68 g/mL and 64.72 ± 0.52 g/g, respectively. The mean sucrose content was 2.29 ± 0.65%. High mean values of phenolic (459.83 ± 1.92 mg gallic acid/kg), flavonoid (54.23 ± 0.62 mg catechin/kg), ascorbic acid (159.70 ± 0.78 mg/kg), AEAC (278.15 ± 4.34 mg/kg), protein (3381.83 ± 6.19 mg/kg) and proline (2131.47 ± 0.90) contents, as well as DPPH (39.57% ± 4.18) and FRAP activities [337.77 ± 1.01 µM Fe (II)/100 g], were also detected, indicating that Algerian honey has a high antioxidant potential. Strong positive correlations were found between flavonoid, proline and ascorbic acid contents and color intensity with DPPH and FRAP values. Thus, the present study revealed that Algerian honey is a good source of antioxidants.

Salicylic acid improves root antioxidant defense system and total antioxidant capacities of flax subjected to cadmium.

PubMed

Belkadhi, Aïcha; De Haro, Antonio; Soengas, Pilar; Obregon, Sara; Cartea, Maria Elena; Djebali, Wahbi; Chaïbi, Wided

2013-07-01

Cadmium (Cd) disrupts the normal growth and development of plants, depending on their tolerance to this toxic element. The present study was focused on the impacts of exogenous salicylic acid (SA) on the response and regulation of the antioxidant defense system and membrane lipids to 16-day-old flax plantlets under Cd stress. Exposure of flax to high Cd concentrations led to strong inhibition of root growth and enhanced lipid peroxides, membrane permeability, protein oxidation, and hydrogen peroxide (H2O2) production to varying degrees. Concomitantly, activities of the antioxidant enzymes catalase (CAT, EC 1.11.1.6), guaïcol peroxydase (GPX, EC 1.11.1.7), ascorbate peroxydase (APX, EC 1.11.1.11), and superoxide dismutase (SOD, EC 1.15.1.1), and the total antioxidant capacities (2,2'-diphenyl-1-picrylhydrazyl (DPPH) scavenging activity and ferric reducing antioxidant power (FRAP)) were significantly altered by Cd. In contrast, exogenous SA greatly reduced the toxic effects of Cd on the root growth, antioxidant system, and membrane lipid content. The Cd-treated plantlets pre-soaked with SA exhibited less lipid and protein oxidation and membrane alteration, as well as a high level of total antioxidant capacities and increased activities of antioxidant enzymes except of CAT. These results may suggest that SA plays an important role in triggering the root antioxidant system, thereby preventing membrane damage as well as the denaturation of its components.

2.0 Angstrom Structure of Prostaglandin H2 Synthase-1 Reconstituted with a Manganese Porphyrin Cofactor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gupta,K.; Selinsky, B.; Loll, P.

2006-01-01

Prostaglandin H{sub 2} synthase (EC 1.14.99.1) is a clinically important drug target that catalyzes two key steps in the biosynthesis of the eicosanoid hormones. The enzyme contains spatially distinct cyclooxygenase and peroxidase active sites, both of which require a heme cofactor. Substitution of ferric heme by Mn{sup III} protoporphyrin IX greatly diminishes the peroxidase activity, but has little effect on the cyclooxygenase activity. Here, the 2.0 Angstrom resolution crystal structure of the Mn{sup III} form of ovine prostaglandin H{sub 2} synthase-1 is described (R = 21.8%, R{sub free} = 23.7%). Substitution of Mn{sup III} for Fe{sup III} causes no structuralmore » perturbations in the protein. However, the out-of-plane displacement of the manganese ion with respect to the porphyrin is greater than that of the iron by approximately 0.2 Angstroms. This perturbation may help to explain the altered catalytic properties of the manganese enzyme.« less

Modulation of paraquat toxicity by beta-carotene at low oxygen partial pressure in chicken embryo fibroblasts.

PubMed

Lawlor, S M; O'Brien, N M

1997-01-01

The efficiency with which beta-carotene protects against oxidative stress in chicken embryo fibroblasts (CEF) at low O2 partial pressures was assessed. Primary cultures of CEF were grown at low O2 partial pressures and oxidatively stressed by exposure to paraquat (PQ). Activities of the antioxidant enzymes superoxide dismutase (EC 1.15.1.1; SOD), catalase (EC 1.11.1.6; CAT) and glutathione peroxidase (EC 1.11.1.9; GSH-Px) were measured as indices of oxidative stress. CEF incubated with 0.25-1.0 mM-PQ for 18 h exhibited increased SOD and CAT activities compared with non-PQ-treated control cells (P < 0.001). No cytotoxicity as indicated by lactate dehydrogenase (EC 1.1.1.27; LDH) release was observed at PQ concentrations below 2.0 mM. Incorporation of added beta-carotene into 0.25 mM-PQ-treated cells prevented the PQ-induced increases in SOD and CAT, and activities were similar to those seen in non-PQ-treated control cells. GSH-Px activity decreased relative to its control value on exposure to 0.25 mM-PQ and beta-carotene prevented this decrease in a dose-dependent manner. The proportion of LDH released from the CEF treated with beta-carotene remained below the control value of 2.5% at all times.

Impact of immobilizing of low molecular weight hyaluronic acid within gelatin-based hydrogel through enzymatic reaction on behavior of enclosed endothelial cells.

PubMed

Khanmohammadi, Mehdi; Sakai, Shinji; Taya, Masahito

2017-04-01

The hydrogels having the ability to promote migration and morphogenesis of endothelial cells (ECs) are useful for fabricating vascularized dense tissues in vitro. The present study explores the immobilization of low molecular weight hyaluronic acid (LMWHA) derivative within gelatin-based hydrogel to stimulate migration of ECs. The LMWHA derivative possessing phenolic hydroxyl moieties (LMWHA-Ph) was bound to gelatin-based derivative hydrogel through the horseradish peroxidase-catalyzed reaction. The motility of ECs was analyzed by scratch migration assay and microparticle-based cell migration assay. The incorporated LMWHA-Ph molecules within hydrogel was found to be preserved stably through covalent bonds during incubation. The free and immobilized LMWHA-Ph did not lose an inherent stimulatory effect on human umbilical vein endothelial cells (HUVECs). The immobilized LMWHA-Ph within gelatin-based hydrogel induced the high motility of HUVECs, accompanied by robust cytoskeleton extension, and cell subpopulation expressing CD44 cell receptor. In the presence of immobilized LMWHA-Ph, the migration distance and the number of existing HUVECs were demonstrated to be encouraged in dose-dependent and time-dependent manners. Based on the results obtained in this work, it was concluded that the enzymatic immobilization of LMWHA-Ph within gelatin-based hydrogel represents a promising approach to promote ECs' motility and further exploitation for vascular tissue engineering applications. Copyright © 2017 Elsevier B.V. All rights reserved.

Hydrogen sulfide prolongs postharvest shelf life of strawberry and plays an antioxidative role in fruits.

PubMed

Hu, Lan-Ying; Hu, Shu-Li; Wu, Jun; Li, Yan-Hong; Zheng, Ji-Lian; Wei, Zhao-Jun; Liu, Jian; Wang, Hui-Li; Liu, Yong-Sheng; Zhang, Hua

2012-09-05

Accumulating evidence shows that hydrogen sulfide (H(2)S) plays various physiological roles in plants, such as seed germination, root organogenesis, abiotic stress tolerance, and senescence of cut flowers. However, whether H(2)S participates in the regulation of ripening and senescence in postharvest fruits remains unknown. In the present study, the effect of H(2)S on postharvest shelf life and antioxidant metabolism in strawberry fruits was investigated. Fumigation with H(2)S gas released from the H(2)S donor NaHS prolonged postharvest shelf life of strawberry fruits in a dose-dependent manner. Strawberry fruits fumigated with various concentrations of H(2)S sustained significantly lower rot index, higher fruit firmness, and kept lower respiration intensity and polygalacturonase activities than controls. Further investigation showed that H(2)S treatment maintained higher activities of catalase, guaiacol peroxidase, ascorbate peroxidase, and glutathione reductase and lower activities of lipoxygenase relative to untreated controls. H(2)S also reduced malondialdehyde, hydrogen peroxide, and superoxide anion to levels below control fruits during storage. Moreover, H(2)S treatment maintained higher contents of reducing sugars, soluble proteins, free amino acid, and endogenous H(2)S in fruits. We interpret these data as indicating that H(2)S plays an antioxidative role in prolonging postharvest shelf life of strawberry fruits.

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

PubMed

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.

Hydrogen Sulfide Prolongs Postharvest Storage of Fresh-Cut Pears (Pyrus pyrifolia) by Alleviation of Oxidative Damage and Inhibition of Fungal Growth

PubMed Central

Gao, Shuai-Ping; Wu, Jun; Li, Yan-Hong; Zheng, Ji-Lian; Han, Yi; Liu, Yong-Sheng; Zhang, Hua

2014-01-01

Hydrogen sulfide (H2S) has proved to be a multifunctional signaling molecule in plants and animals. Here, we investigated the role of H2S in the decay of fresh-cut pears (Pyrus pyrifolia). H2S gas released by sodium hydrosulfide (NaHS) prolonged the shelf life of fresh-cut pear slices in a dose-dependent manner. Moreover, H2S maintained higher levels of reducing sugar and soluble protein in pear slices. H2S significantly reduced the accumulation of hydrogen peroxide (H2O2), superoxide radicals (•O2 −) and malondialdehyde (MDA). Further investigation showed that H2S fumigation up-regulated the activities of antioxidant enzymes ascorbate peroxidase (APX), catalase (CAT), and guaiacol peroxidase (POD), while it down-regulated those of lipoxygenase (LOX), phenylalanine ammonia lyase (PAL) and polyphenol oxidase (PPO). Furthermore, H2S fumigation effectively inhibited the growth of two fungal pathogens of pear, Aspergillus niger and Penicillium expansum, suggesting that H2S can be developed as an effective fungicide for postharvest storage. The present study implies that H2S is involved in prolonging postharvest storage of pears by acting as an antioxidant and fungicide. PMID:24454881

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

PubMed Central

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

Acclimation of hydrogen peroxide enhances salt tolerance by activating defense-related proteins in Panax ginseng C.A. Meyer.

PubMed

Sathiyaraj, Gayathri; Srinivasan, Sathiyaraj; Kim, Yu-Jin; Lee, Ok Ran; Parvin, Shonana; Balusamy, Sri Renuka Devi; Khorolragchaa, Atlanzul; Yang, Deok Chun

2014-06-01

The effect of exogenously applied hydrogen peroxide on salt stress tolerance was investigated in Panax ginseng. Pretreatment of ginseng seedlings with 100 μM H2O2 increased the physiological salt tolerance of the ginseng plant and was used as the optimum concentration to induce salt tolerance capacity. Treatment with exogenous H2O2 for 2 days significantly enhanced salt stress tolerance in ginseng seedlings by increasing the activities of ascorbate peroxidase, catalase and guaiacol peroxidase and by decreasing the concentrations of malondialdehyde (MDA) and endogenous H2O2 as well as the production rate of superoxide radical (O2(-)). There was a positive physiological effect on the growth and development of salt-stressed seedlings by exogenous H2O2 as measured by ginseng dry weight and both chlorophyll and carotenoid contents. Exogenous H2O2 induced changes in MDA, O2(-), antioxidant enzymes and antioxidant compounds, which are responsible for increases in salt stress tolerance. Salt treatment caused drastic declines in ginseng growth and antioxidants levels; whereas, acclimation treatment with H2O2 allowed the ginseng seedlings to recover from salt stress by up-regulation of defense-related proteins such as antioxidant enzymes and antioxidant compounds.

Explosive Tandem and Segmental Duplications of Multigenic Families in Eucalyptus grandis

PubMed Central

Li, Qiang; Yu, Hong; Cao, Phi Bang; Fawal, Nizar; Mathé, Catherine; Azar, Sahar; Cassan-Wang, Hua; Myburg, Alexander A.; Grima-Pettenati, Jacqueline; Marque, Christiane; Teulières, Chantal; Dunand, Christophe

2015-01-01

Plant organisms contain a large number of genes belonging to numerous multigenic families whose evolution size reflects some functional constraints. Sequences from eight multigenic families, involved in biotic and abiotic responses, have been analyzed in Eucalyptus grandis and compared with Arabidopsis thaliana. Two transcription factor families APETALA 2 (AP2)/ethylene responsive factor and GRAS, two auxin transporter families PIN-FORMED and AUX/LAX, two oxidoreductase families (ascorbate peroxidases [APx] and Class III peroxidases [CIII Prx]), and two families of protective molecules late embryogenesis abundant (LEA) and DNAj were annotated in expert and exhaustive manner. Many recent tandem duplications leading to the emergence of species-specific gene clusters and the explosion of the gene numbers have been observed for the AP2, GRAS, LEA, PIN, and CIII Prx in E. grandis, while the APx, the AUX/LAX and DNAj are conserved between species. Although no direct evidence has yet demonstrated the roles of these recent duplicated genes observed in E. grandis, this could indicate their putative implications in the morphological and physiological characteristics of E. grandis, and be the key factor for the survival of this nondormant species. Global analysis of key families would be a good criterion to evaluate the capabilities of some organisms to adapt to environmental variations. PMID:25769696

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

PubMed

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.

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

PubMed Central

Yang, Feng; Huang, Zhong-Qin; Tang, Jun; Hu, Kang-Di

2017-01-01

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. PMID:29155872

Plant responses to water stress

PubMed Central

Kar, Rup Kumar

2011-01-01

Terrestrial plants most often encounter drought stress because of erratic rainfall which has become compounded due to present climatic changes.Responses of plants to water stress may be assigned as either injurious change or tolerance index. One of the primary and cardinal changes in response to drought stress is the generation of reactive oxygen species (ROS), which is being considered as the cause of cellular damage. However, recently a signaling role of such ROS in triggering the ROS scavenging system that may confer protection or tolerance against stress is emerging. Such scavenging system consists of antioxidant enzymes like SOD, catalase and peroxidases, and antioxidant compounds like ascorbate, reduced glutathione; a balance between ROS generation and scavenging ultimately determines the oxidative load. As revealed in case of defence against pathogen, signaling via ROS is initiated by NADPH oxidase-catalyzed superoxide generation in the apoplastic space (cell wall) followed by conversion to hydrogen peroxide by the activity of cell wall-localized SOD. Wall peroxidase may also play role in ROS generation for signaling. Hydrogen peroxide may use Ca2+ and MAPK pathway as downstream signaling cascade. Plant hormones associated with stress responses like ABA and ethylene play their role possibly via a cross talk with ROS towards stress tolerance, thus projecting a dual role of ROS under drought stress. PMID:22057331

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

PubMed

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.

Triticum aestivum WRAB18 functions in plastids and confers abiotic stress tolerance when overexpressed in Escherichia coli and Nicotiania benthamiana.

PubMed

Wang, Xiaoyu; Zhang, Linsheng; Zhang, Yane; Bai, Zhenqing; Liu, Hao; Zhang, Dapeng

2017-01-01

WRAB18, an ABA-inducible protein belongs to the third family of late embryogenesis abundant (LEA) proteins which can be induced by different biotic or abiotic stresses. In the present study, WRAB18 was cloned from the Zhengyin 1 cultivar of Triticum aestivum and overexpressed in Escherichia coli to explore its effects on the growth of E. coli under different abiotic stresses. Results suggested the enhanced exhibition of tolerance of E. coli to these stresses. Meanwhile, the WRAB18-transgenic tobacco plants were obtained to analyze the stress-related enzymatic activities of ascorbate peroxidase (APX), peroxidase (POD) and superoxide dismutase (SOD), and to quantify the content of malonaldehyde (MDA) under osmotic stress, high salinity, and low and high temperature stress. The activities of APX, POD and SOD in the transgenic tobacco lines were higher while the content of MDA was lower than those of WT lines. Moreover, plastid localization of WRAB18 in Nicotiana benthamiana plasma cells were found fusing with GFP. In addition, purified WRAB18 protein protected LDH (Lactate dehydrogenase) enzyme activity in vitro from various stress conditions. In brief, WRAB18 protein shows protective action behaving as a "molecular shield" in both prokaryotic and eukaryotic cells under various abiotic stresses, not only during ABA stress.

Isolation of plant-growth-promoting rhizobacteria from rhizospheric soil of halophytes and their impact on maize (Zea mays L.) under induced soil salinity.

PubMed

Ullah, Sami; Bano, Asghari

2015-04-01

The present investigation was aimed to scrutinize the salt tolerance potential of plant-growth-promoting rhizobacteria (PGPR) isolated from rhizospheric soil of selected halophytes (Atriplex leucoclada, Haloxylon salicornicum, Lespedeza bicolor, Suaeda fruticosa, and Salicornica virginica) collected from high-saline fields (electrical conductivity 4.3-5.5) of District Mardan, Pakistan. Five PGPR strains were identified using 16S rRNA amplification and sequence analysis. Bacillus sp., isolated from rhizospheric soil of Atriplex leucoclada, and Arthrobacter pascens, isolated from rhizospheric soil of Suaeda fruticosa, are active phosphate solubilizers and bacteriocin and siderophore producers; hence, their inoculation and co-inoculation on maize ('Rakaposhi') under induced salinity stress enhanced shoot and root length and shoot and root fresh and dry mass. The accumulation of osmolytes, including sugar and proline, and the elevation of antioxidant enzymes activity, including superoxide dismutase, peroxidase, catalase, and ascorbate peroxidase, were enhanced in the maize variety when inoculated and co-inoculated with Bacillus sp. and Arthrobacter pascens. The PGPR (Bacillus sp. and A. pascens) isolated from the rhizosphere of the mentioned halophytes species showed reliability in growth promotion of maize crop in all the physiological parameters; hence, they can be used as bio-inoculants for the plants growing under salt stress.

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

PubMed

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.

A simple method for plasma total vitamin C analysis suitable for routine clinical laboratory use.

PubMed

Robitaille, Line; Hoffer, L John

2016-04-21

In-hospital hypovitaminosis C is highly prevalent but almost completely unrecognized. Medical awareness of this potentially important disorder is hindered by the inability of most hospital laboratories to determine plasma vitamin C concentrations. The availability of a simple, reliable method for analyzing plasma vitamin C could increase opportunities for routine plasma vitamin C analysis in clinical medicine. Plasma vitamin C can be analyzed by high performance liquid chromatography (HPLC) with electrochemical (EC) or ultraviolet (UV) light detection. We modified existing UV-HPLC methods for plasma total vitamin C analysis (the sum of ascorbic and dehydroascorbic acid) to develop a simple, constant-low-pH sample reduction procedure followed by isocratic reverse-phase HPLC separation using a purely aqueous low-pH non-buffered mobile phase. Although EC-HPLC is widely recommended over UV-HPLC for plasma total vitamin C analysis, the two methods have never been directly compared. We formally compared the simplified UV-HPLC method with EC-HPLC in 80 consecutive clinical samples. The simplified UV-HPLC method was less expensive, easier to set up, required fewer reagents and no pH adjustments, and demonstrated greater sample stability than many existing methods for plasma vitamin C analysis. When compared with the gold-standard EC-HPLC method in 80 consecutive clinical samples exhibiting a wide range of plasma vitamin C concentrations, it performed equivalently. The easy set up, simplicity and sensitivity of the plasma vitamin C analysis method described here could make it practical in a normally equipped hospital laboratory. Unlike any prior UV-HPLC method for plasma total vitamin C analysis, it was rigorously compared with the gold-standard EC-HPLC method and performed equivalently. Adoption of this method could increase the availability of plasma vitamin C analysis in clinical medicine.

In Situ Mass Spectrometric Monitoring of the Dynamic Electrochemical Process at the Electrode–Electrolyte Interface: a SIMS Approach

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Zhaoying; Zhang, Yanyan; Liu, Bingwen

The in situ molecular characterization of reaction intermediates and products at electrode-electrolyte interfaces is central to mechanistic studies of complex electrochemical processes, yet a great challenge. The coupling of electrochemistry (EC) and mass spectrometry (MS) has seen rapid development and found broad applicability in tackling challenges in analytical and bioanalytical chemistry. However, few truly in situ and real-time EC-MS studies have been reported at electrode-electrolyte interfaces. An innovative EC-MS coupling method named in situ liquid secondary ion mass spectrometry (SIMS) was recently developed by combining SIMS with a vacuum compatible microfluidic electrochemical device. Using this novel capability we report themore » first in situ elucidation of the electro-oxidation mechanism of a biologically significant organic compound, ascorbic acid (AA), at the electrode-electrolyte interface. The short-lived radical intermediate was successfully captured, which had not been detected directly before. Moreover, we demonstrated the power of this new technique in real-time monitoring of the formation and dynamic evolution of electrical double layers at the electrode-electrolyte interface. This work suggests further promising applications of in situ liquid SIMS in studying more complex chemical and biological events at the electrode-electrolyte interface.« less

Combined modified atmosphere packaging and low temperature storage delay lignification and improve the defense response of minimally processed water bamboo shoot.

PubMed

Song, Lili; Chen, Hangjun; Gao, Haiyan; Fang, Xiangjun; Mu, Honglei; Yuan, Ya; Yang, Qian; Jiang, Yueming

2013-09-04

Minimally processed water bamboo shoot (WBS) lignifies and deteriorates rapidly at room temperature, which limits greatly its marketability. This study was to investigate the effect of modified atmosphere packaging (MAP) on the sensory quality index, lignin formation, production of radical oxygen species (ROS) and activities of scavenging enzymes, membrane integrity and energy status of minimally processed WBS when packaged with or without the sealed low-density polyethylene (LDPE) bags, and then stored at 20°C for 9 days or 2°C for 60 days. The sensory quality of minimally processed WBS decreased quickly after 6 days of storage at 20°C. Low temperature storage maintained a higher sensory quality index within the first 30 days, but exhibited higher contents of lignin and hydrogen peroxide (H2O2) as compared with non-MAP shoots at 20°C. Combined MAP and low temperature storage not only maintained good sensory quality after 30 days, but also reduced significantly the increases in lignin content, superoxide anion (O2.-) production rate, H2O2 content and membrane permeability, maintained high activities of superoxide dismutase (SOD), catalase (CAT) and ascorbate peroxidase (APX), and reduced the increase in activities of lipase, phospholipase D (PLD) and lipoxygenase (LOX). Furthermore, the minimally processed WBS under MAP condition exhibited higher energy charge (EC) and lower adenosine monophosphate (AMP) content by the end of storage (60 days) at 2°C than those without MAP or stored for 9 days at 20°C. These results indicated that MAP in combination with low temperature storage reduced lignification of minimally processed WBS, which was closely associated with maintenance of energy status and enhanced activities of antioxidant enzymes, as well as reduced alleviation of membrane damage caused by ROS.

Combined modified atmosphere packaging and low temperature storage delay lignification and improve the defense response of minimally processed water bamboo shoot

PubMed Central

2013-01-01

Background Minimally processed water bamboo shoot (WBS) lignifies and deteriorates rapidly at room temperature, which limits greatly its marketability. This study was to investigate the effect of modified atmosphere packaging (MAP) on the sensory quality index, lignin formation, production of radical oxygen species (ROS) and activities of scavenging enzymes, membrane integrity and energy status of minimally processed WBS when packaged with or without the sealed low-density polyethylene (LDPE) bags, and then stored at 20°C for 9 days or 2°C for 60 days. Results The sensory quality of minimally processed WBS decreased quickly after 6 days of storage at 20°C. Low temperature storage maintained a higher sensory quality index within the first 30 days, but exhibited higher contents of lignin and hydrogen peroxide (H2O2) as compared with non-MAP shoots at 20°C. Combined MAP and low temperature storage not only maintained good sensory quality after 30 days, but also reduced significantly the increases in lignin content, superoxide anion (O2.-) production rate, H2O2 content and membrane permeability, maintained high activities of superoxide dismutase (SOD), catalase (CAT) and ascorbate peroxidase (APX), and reduced the increase in activities of lipase, phospholipase D (PLD) and lipoxygenase (LOX). Furthermore, the minimally processed WBS under MAP condition exhibited higher energy charge (EC) and lower adenosine monophosphate (AMP) content by the end of storage (60 days) at 2°C than those without MAP or stored for 9 days at 20°C. Conclusion These results indicated that MAP in combination with low temperature storage reduced lignification of minimally processed WBS, which was closely associated with maintenance of energy status and enhanced activities of antioxidant enzymes, as well as reduced alleviation of membrane damage caused by ROS. PMID:24006941

Pyranose Oxidase, a Major Source of H(2)O(2) during Wood Degradation by Phanerochaete chrysosporium, Trametes versicolor, and Oudemansiella mucida.

PubMed

Daniel, G; Volc, J; Kubatova, E

1994-07-01

The production of the H(2)O(2)-generating enzyme pyranose oxidase (POD) (EC 1.1.3.10) (synonym, glucose 2-oxidase), two ligninolytic peroxidases, and laccase in wood decayed by three white rot fungi was investigated by correlated biochemical, immunological, and transmission electron microscopic techniques. Enzyme activities were assayed in extracts from decayed birch wood blocks obtained by a novel extraction procedure. With the coupled peroxidase-chromogen (3-dimethylaminobenzoic acid plus 3-methyl-2-benzothiazolinone hydrazone hydrochloride) spectrophotometric assay, the highest POD activities were detected in wood blocks degraded for 4 months and were for Phanerochaete chrysosporium (149 mU g [dry weight] of decayed wood), Trametes versicolor (45 mU g), and Oudemansiella mucida (1.2 mU g), corresponding to wood dry weight losses of 74, 58, and 13%, respectively. Mn-dependent peroxidase activities in the same extracts were comparable to those of POD, while lignin peroxidase activity was below the detection limit for all fungi with the veratryl alcohol assay. Laccase activity was high with T. versicolor (422 mU g after 4 months), in trace levels with O. mucida, and undetectable in P. chrysosporium extracts. Evidence for C-2 specificity of POD was shown by thin-layer chromatography detection of 2-keto-d-glucose as the reaction product. By transmission electron microscopy-immunocytochemistry, POD was found to be preferentially localized in the hyphal periplasmic space of P. chrysosporium and O. mucida and associated with membranous materials in hyphae growing within the cell lumina or cell walls of partially and highly degraded birch fibers. An extracellular distribution of POD associated with slime coating wood cell walls was also noted. The periplasmic distribution in hyphae and extracellular location of POD are consistent with the reported ultrastructural distribution of H(2)O(2)-dependent Mn-dependent peroxidases. This fact and the dominant presence of POD and Mn-dependent peroxidase in extracts from degraded wood suggest a cooperative role of the two enzymes during white rot decay by the test fungi.

Characterisation of phenol oxidase and peroxidase from maize silk.

PubMed

Sukalović, V Hadzi-Tasković; Veljović-Jovanović, S; Maksimović, J Dragisić; Maksimović, V; Pajić, Z

2010-05-01

Silk of some maize genotypes contains a high level of phenolics that undergo enzymatic oxidation to form quinones, which condense among themselves or with proteins to form brown pigments. Two phenolic oxidizing enzymes, peroxidase (POD; EC 1.11.1.7) and polyphenol oxidase (PPO; EC 1.10.3.1), from maize (Zea mays L.) silk were characterised with respect to their preferred substrate, different isoforms and specific effectors. One browning silk sample with high, and two non-browning samples with low phenolic content were investigated. Although POD oxidizes a wide range of phenolic substrates in vitro, its activity rate was independent of silk phenolic content. PPO activity, detected with o-diphenolic substrates, was abundant only in browning silk, and low or absent in non-browning silk. Pollination increased POD but not PPO activity. Isoelectric-focusing (IEF) and specific staining for POD and PPO showed a high degree of polymorphism that varied with silk origin. The IEF pattern of POD revealed a number of anionic and several cationic isoenzymes, with the most pronounced having neutral pI 7 and a basic isoform with pI 10. Detected isoforms of PPO were anionic, except for one neutral form found only in browning silk, and occupied positions different from those of POD. Different inhibitory effects of NaN(3), EDTA, KCN, and L-cysteine, as well as different impacts of a variety of cations on the oxidation of chlorogenic acid, mediated by PPO or POD, were detected. The findings are discussed in terms of a possible roles of these enzymes in defence and pollination.

Tolerance to Stress Combination in Tomato Plants: New Insights in the Protective Role of Melatonin.

PubMed

Martinez, Vicente; Nieves-Cordones, Manuel; Lopez-Delacalle, Maria; Rodenas, Reyes; Mestre, Teresa C; Garcia-Sanchez, Francisco; Rubio, Francisco; Nortes, Pedro A; Mittler, Ron; Rivero, Rosa M

2018-02-28

Abiotic stresses such as drought, heat or salinity are major causes of yield loss worldwide. Recent studies have revealed that the acclimation of plants to a combination of different environmental stresses is unique and therefore cannot be directly deduced from studying the response of plants to each of the different stresses applied individually. The efficient detoxification of reactive oxygen species (ROS) is thought to play a key role in enhancing the tolerance of plants to abiotic stresses. Here, we report on the role of melatonin in the protection of the photosynthetic apparatus through the increase in ROS detoxification in tomato plants grown under the combination of salinity and heat, two of the most common abiotic stresses known to act jointly. Plants treated with exogenous melatonin showed a different modulation in the expression on some antioxidant-related genes and their related enzymes. More specifically, ascorbate peroxidase, glutathione reductase, glutathione peroxidase and phospholipid hydroperoxide glutathione peroxidase (APX, GR, GPX and Ph-GPX, resepctively) showed an antagonistic regulation as compared to plants that did not receive melatonin. This translated into a better antioxidant capacity and to a lesser ROS accumulation under stress combination. The performance of the photosynthesis parameters and the photosystems was also increased in plants treated with exogenous melatonin under the combination of salinity and heat. In accordance with these findings, tomato plants treated with melatonin were found to grow better under stress combination that the non-treated ones. Our study highlights the important role that exogenous melatonin plays in the acclimation of plants to a combination of two different abiotic stresses, and how this compound can specifically regulate oxidative stress-related genes and enzymes to increase plant tolerance.

Peroxidative permeabilization of liposomes induced by cytochrome c/cardiolipin complex.

PubMed

Firsov, Alexander M; Kotova, Elena A; Korepanova, Evgeniya A; Osipov, Anatoly N; Antonenko, Yuri N

2015-03-01

Interaction of cytochrome c with mitochondrial cardiolipin converting this electron transfer protein into peroxidase is accepted to play an essential role in apoptosis. Cytochrome c/cardiolipin peroxidase activity was found here to cause leakage of carboxyfluorescein, sulforhodamine B and 3-kDa (but not 10-kDa) fluorescent dextran from liposomes. A marked decrease in the amplitude of the autocorrelation function was detected with a fluorescence correlation spectroscopy setup upon incubation of dye-loaded cardiolipin-containing liposomes with cytochrome c and H2O2, thereby showing release of fluorescent markers from liposomes. The cytochrome c/H2O2-induced liposome leakage was suppressed upon increasing the ionic strength, in contrast to the leakage provoked by Fe/ascorbate, suggesting that the binding of cyt c to negatively-charged membranes was required for the permeabilization process. The cyt c/H2O2-induced liposome leakage was abolished by cyanide presumably competing with H2O2 for coordination with the central iron atom of the heme in cyt c. The cytochrome c/H2O2 permeabilization activity was substantially diminished by antioxidants (trolox, butylhydroxytoluene and quercetin) and was precluded if fully saturated tetramyristoyl-cardiolipin was substituted for bovine heart cardiolipin. These data favor the involvement of oxidized cardiolipin molecules in membrane permeabilization resulting from cytochrome c/cardiolipin peroxidase activity. In agreement with previous observations, high concentrations of cyt c induced liposome leakage in the absence of H2O2, however this process was not sensitive to antioxidants and cyanide suggesting direct membrane poration by the protein without the involvement of lipid peroxidation. Copyright © 2014 Elsevier B.V. All rights reserved.

Effect of lead on phytotoxicity, growth, biochemical alterations and its role on genomic template stability in Sesbania grandiflora: a potential plant for phytoremediation.

PubMed

Malar, Srinivasan; Manikandan, Rajendiran; Favas, Paulo J C; Vikram Sahi, Shivendra; Venkatachalam, Perumal

2014-10-01

The present study was aimed at evaluating phytotoxicity of various concentrations of lead nitrate (0, 100, 200, 400, 600, 800 and 1000mgL(-1)) in Sesbania grandiflora. The seedling growth was significantly affected (46%) at 1000mgL(-1) lead (Pb) treatment. Accumulation of Pb content was high in root (118mgg(-1) dry weight) than in shoot (23mgg(-1) dry weight). The level of photosynthetic pigment contents was gradually increased with increasing concentrations of Pb. Malondialdehyde (MDA) content increased in both the leaves as well as roots at 600mgL(-1) Pb treatment and decreased at higher concentrations. The activity of antioxidative enzymes such as superoxide dismutase and peroxidase were positively correlated with Pb treatment while catalase and ascorbate peroxidase activities increased up to 600mgL(-1) Pb treatment and then slightly decreased at higher concentrations. Isozyme banding pattern revealed the appearance of additional isoforms of superoxide dismutase and peroxidase in Pb treated leaf tissues. Isozyme band intensity was more consistent with the respective changes in antioxidative enzyme activities. Random amplified polymorphic DNA results indicated that genomic template stability (GTS) was significantly affected based on Pb concentrations. The present results suggest that higher concentrations of Pb enhanced the oxidative damage by over production of ROS in S. grandiflora that had potential tolerance mechanism to Pb as evidenced by increased level of photosynthetic pigments, MDA content, and the level of antioxidative enzymes. Retention of high levels of Pb in root indicated that S. grandiflora has potential for phytoextracting heavy metals by rhizofiltration. Copyright © 2014 Elsevier Inc. All rights reserved.

The Different Physiological and Antioxidative Responses of Zucchini and Cucumber to Sewage Sludge Application.

PubMed

Wyrwicka, Anna; Urbaniak, Magdalena

2016-01-01

The present study investigates the effect of soil amended with sewage sludge on oxidative changes in zucchini and cucumber plants (Cucurbitaceae) and the consequent activation of their antioxidative systems and detoxification mechanisms. The plants were grown in pots containing soil amended with three concentrations of sewage sludge (1.8 g, 5.4 g and 10.8 g per pot), while controls were potted with vegetable soil. The activities of three antioxidative enzymes, ascorbate peroxidase (APx), catalase (CAT) and guaiacol peroxidase (POx), were assessed, as well as of the detoxifying enzyme S-glutathione transferase (GST). Lipid peroxidation was evaluated by measuring the extent of oxidative damage; α-tocopherol content, the main lipophilic antioxidant, was also measured. Visible symptoms of leaf blade damage after sewage sludge application occurred only on the zucchini plants. The zucchini and cucumber plants showed a range of enzymatic antioxidant responses to sewage sludge application. While APx and POx activities increased significantly with increasing sludge concentration in the zucchini plants, they decreased in the cucumber plants. Moreover, although the activity of these enzymes increased gradually with increasing doses of sewage sludge, these levels fell at the highest dose. An inverse relationship between peroxidases activity and CAT activity was observed in both investigated plant species. In contrast, although GST activity increased progressively with sludge concentration in both the zucchini and cucumber leaves, the increase in GST activity was greater in the zucchini plants, being visible at the lowest dose used. The results indicate that signs of sewage sludge toxicity were greater in zucchini than cucumber, and its defense reactions were mainly associated with increases in APx, POx and GST activity.

The Different Physiological and Antioxidative Responses of Zucchini and Cucumber to Sewage Sludge Application

PubMed Central

Wyrwicka, Anna; Urbaniak, Magdalena

2016-01-01

The present study investigates the effect of soil amended with sewage sludge on oxidative changes in zucchini and cucumber plants (Cucurbitaceae) and the consequent activation of their antioxidative systems and detoxification mechanisms. The plants were grown in pots containing soil amended with three concentrations of sewage sludge (1.8 g, 5.4 g and 10.8 g per pot), while controls were potted with vegetable soil. The activities of three antioxidative enzymes, ascorbate peroxidase (APx), catalase (CAT) and guaiacol peroxidase (POx), were assessed, as well as of the detoxifying enzyme S-glutathione transferase (GST). Lipid peroxidation was evaluated by measuring the extent of oxidative damage; α-tocopherol content, the main lipophilic antioxidant, was also measured. Visible symptoms of leaf blade damage after sewage sludge application occurred only on the zucchini plants. The zucchini and cucumber plants showed a range of enzymatic antioxidant responses to sewage sludge application. While APx and POx activities increased significantly with increasing sludge concentration in the zucchini plants, they decreased in the cucumber plants. Moreover, although the activity of these enzymes increased gradually with increasing doses of sewage sludge, these levels fell at the highest dose. An inverse relationship between peroxidases activity and CAT activity was observed in both investigated plant species. In contrast, although GST activity increased progressively with sludge concentration in both the zucchini and cucumber leaves, the increase in GST activity was greater in the zucchini plants, being visible at the lowest dose used. The results indicate that signs of sewage sludge toxicity were greater in zucchini than cucumber, and its defense reactions were mainly associated with increases in APx, POx and GST activity. PMID:27327659

Effects of treated industrial wastewaters and temperatures on growth and enzymatic activities of duckweed (Lemna minor L.).

PubMed

Basiglini, E; Pintore, M; Forni, C

2018-05-30

The efficacy of the removal of contaminants from wastewater depends on physico-chemical properties of pollutants and the efficiency of treatment plant. Sometimes, low amounts of toxic compounds can be still present in the treated sewage. In this work we considered the effects of contaminant residues in treated wastewaters and of temperatures on Lemna minor L. Treated effluent waters were collected, analyzed and used as duckweed growth medium. In order to better understand the effects of micropollutants and seasonal variation, the plants were grown under ambient conditions for seven days in summer and winter. Relative growth rate, pigments and phenolic compounds concentrations were determined, as well as the activities of catalase (CAT), ascorbate peroxidase (APX), guaiacol peroxidase (G-POD) and polyphenol oxidase (PPO). The pollutant concentrations varied in the two seasons, depending on the industrial and municipal activities and efficiency of treatments. Treated waters contained heavy metals, nitrogenous and phosphorus compounds, surfactants and hydrocarbons. Compared to the control, duckweed growth of treated plants decreased by 25% in summer, while in the winter due to the lower temperatures and the presence of pollutants was completely impeded. The amounts of photosynthetic pigments of treated plants were not significantly affected in the summer, while they were higher than the control in the winter when the effluent had a high nitrogen amount. High CAT activity was registered in both seasons. Treated plants had significantly lower APX activity in the summer (53%) and winter (59%) respect to the controls. The observed inhibition of the peroxidase activities in the exposed plants, confirms the controversy existing in the literature about the variability of enzymatic response in stress condition. Copyright © 2018 Elsevier Inc. All rights reserved.

Cadmium toxicity in Maize (Zea mays L.): consequences on antioxidative systems, reactive oxygen species and cadmium accumulation.

PubMed

Anjum, Shakeel Ahmad; Tanveer, Mohsin; Hussain, Saddam; Bao, Mingchen; Wang, Longchang; Khan, Imran; Ullah, Ehsan; Tung, Shahbaz Atta; Samad, Rana Abdul; Shahzad, Babar

2015-11-01

Increased cadmium (Cd) accumulation in soils has led to tremendous environmental problems, with pronounced effects on agricultural productivity. Present study investigated the effects of Cd stress imposed at various concentrations (0, 75, 150, 225, 300, 375 μM) on antioxidant activities, reactive oxygen species (ROS), Cd accumulation, and productivity of two maize (Zea mays L.) cultivars viz., Run Nong 35 and Wan Dan 13. Considerable variations in Cd accumulation and in behavior of antioxidants and ROS were observed under Cd stress in both maize cultivars, and such variations governed by Cd were concentration dependent. Exposure of plant to Cd stress considerably increased Cd concentration in all plant parts particularly in roots. Wan Dan 13 accumulated relatively higher Cd in root, stem, and leaves than Run Nong 35; however, in seeds, Run Nong 35 recorded higher Cd accumulation. All the Cd toxicity levels starting from 75 μM enhanced H2O2 and MDA concentrations and triggered electrolyte leakage in leaves of both cultivars, and such an increment was more in Run Nong 35. The ROS were scavenged by the enhanced activities of superoxide dismutase, peroxidase, catalase, ascorbate peroxidase, and glutathione peroxidase in response to Cd stress, and these antioxidant activities were higher in Wan Dan 13 compared with Run Nong 35 at all Cd toxicity levels. The grain yield of maize was considerably reduced particularly for Run Nong 35 under different Cd toxicity levels as compared with control. The Wan Dan 13 was better able to alleviate Cd-induced oxidative damage which was attributed to more Cd accumulation in roots and higher antioxidant activities in this cultivar, suggesting that manipulation of these antioxidants and enhancing Cd accumulation in roots may lead to improvement in Cd stress tolerance.

Fat Metabolism in Higher Plants

PubMed Central

Jacobson, Bruce S.; Jaworski, J. G.; Stumpf, P. K.

1974-01-01

Stearyl-acyl carrier protein desaturase (EC 1.14.99.6), present in the stroma fraction of spinach (Spinacia oleracea) chloroplasts, rapidly desaturated enzymatically prepared stearyl-acyl carrier protein to oleic acid. No other substrates were desaturated. In addition to stearyl-acyl carrier protein, reduced ferredoxin was an essential component of the system. The electron donor systems were either ascorbate, dichlorophenolindophenol, photosystem I and light, or NADPH and ferredoxin-NADP reductase. The desaturase was more active in extracts prepared from chloroplasts obtained from immature spinach leaves than from mature leaves. Stearyl-acyl carrier protein desaturase also occurs in soluble extracts of avocado (Persea americana Mill.) mesocarp and of developing safflower (Carthamus tinctorius) seeds. PMID:16658913

Tailor-made biocatalysts based on scarcely studied acidic horseradish peroxidase for biodegradation of reactive dyes.

PubMed

Janović, Barbara S; Mićić Vićovac, Milica Lj; Vujčić, Zoran M; Vujčić, Miroslava T

2017-02-01

Peroxidases (EC 1.11.1.7) have enormous biotechnological applications. Usage of more abundant, basic isoforms of peroxidases in diagnostic kits and/or in immunochemistry has led to under exploitation and disregard of horseradish peroxidase (HRP) acidic isoforms. Therefore, acidic horseradish peroxidase (HRP-A) isoenzyme was used for the preparation of a biocatalyst with improved ability in dye decolorization. Ten biocatalysts were prepared by covalent binding of enzyme to chitosan and alginate, adsorption followed by cross-linking on inorganic support (aluminum oxide), and encapsulation in spherical calcium alginate beads via polyethylene glycol. Model dyes of 50 to 175 mg l -1 were removed by the biocatalysts. Among the tested biocatalysts, the three with the highest specific activity and biodegradation rate were further studied (Chitosan-HRP, Al-Gel-HRP and Al-HRP-Gel). The impact of hydrogen peroxide concentration on dye decolorization was examined on the Chitosan-HRP biocatalyst, since the HRP is susceptible to inhibition/inactivation by high H 2 O 2 . On the other hand, H 2 O 2 is needed as a co-substrate for the HRP, and the H 2 O 2 /dye ratio can greatly influence decolorization efficiency. Concentrations of H 2 O 2 ranging from 0.22 to 4.4 mM showed no difference in terms of impact on the biocatalyst decolorization efficiency. The high decolorization efficiency of the biocatalysts was validated by the removal of 25 and 100 mg l -1 anthraquinone (Remazol Brilliant Blue R (RBBR)), triphenylmethane (Coomassie Brilliant Blue (CBB)), acridine (Acridine Orange (AO)), and formazan metal complex dye (Reactive Blue 52 (RB52)). After the seven consecutive decolorization cycles, the decolorization was still 53, 78, and 67% of the initial dye for the Al-HRP-Gel, Al-Gel-HRP, and Chitosan-HRP immobilizate, respectively. The results obtained showed potential of otherwise neglected acidic HRP isoforms as a cost-effective biocatalyst with significant potential in wastewater dyestuff treatment.

Exogenous sodium nitroprusside and glutathione alleviate copper toxicity by reducing copper uptake and oxidative damage in rice (Oryza sativa L.) seedlings.

PubMed

Mostofa, Mohammad Golam; Seraj, Zeba Islam; Fujita, Masayuki

2014-11-01

Nitric oxide (NO) and glutathione (GSH) regulate a variety of physiological processes and stress responses; however, their involvement in mitigating Cu toxicity in plants has not been extensively studied. This study investigated the interactive effect of exogenous sodium nitroprusside (SNP) and GSH on Cu homeostasis and Cu-induced oxidative damage in rice seedlings. Hydroponically grown 12-day-old seedlings were subjected to 100 μM CuSO4 alone and in combination with 200 μM SNP (an NO donor) and 200 μM GSH. Cu exposure for 48 h resulted in toxicity symptoms such as stunted growth, chlorosis, and rolling in leaves. Cu toxicity was also manifested by a sharp increase in lipoxygenase (LOX) activity, lipid peroxidation (MDA), hydrogen peroxide (H2O2), proline (Pro) content, and rapid reductions in biomass, chlorophyll (Chl), and relative water content (RWC). Cu-caused oxidative stress was evident by overaccumulation of reactive oxygen species (ROS; superoxide (O2 (•-)) and H2O2). Ascorbate (AsA) content decreased while GSH and phytochelatin (PC) content increased significantly in Cu-stressed seedlings. Exogenous SNP, GSH, or SNP + GSH decreased toxicity symptoms and diminished a Cu-induced increase in LOX activity, O2 (•-), H2O2, MDA, and Pro content. They also counteracted a Cu-induced increase in superoxide dismutase (SOD), ascorbate peroxidase (APX), glutathione reductase (GR), monodehydroascorbate reductase (MDHAR), and glyoxalase I and glyoxalase II activities, which paralleled changes in ROS and MDA levels. These seedlings also showed a significant increase in catalase (CAT), glutathione peroxidase (GPX), dehydroascorbate reductase (DHAR), glutathione S-transferase (GST) activities, and AsA and PC content compared with the seedlings stressed with Cu alone. Cu analysis revealed that SNP and GSH restricted the accumulation of Cu in the roots and leaves of Cu-stressed seedlings. Our results suggest that Cu exposure provoked an oxidative burden while reduced Cu uptake and modulating the antioxidant defense and glyoxalase systems by adding SNP and GSH play an important role in alleviating Cu toxicity. Furthermore, the protective action of GSH and SNP + GSH was more efficient than SNP alone.

The physiological and biochemical effects of salicylic acid on sunflowers (Helianthus annuus) exposed to flurochloridone.

PubMed

Kaya, Armagan; Yigit, Emel

2014-08-01

In this study, we comparatively evaluated the effects of the flurochloridone as well as flurochloridone and exogenously applied salicylic acid (SA) on Helianthus annuus L. to find out herbicide-induced toxicity reducing influence of SA. We examined and compared the physiological and biochemical effects of different concentrations of flurochloridone (11, 32 and 72 mM) in both the SA pre-treated and non-treated plants. The plants treated with flurochloridone exhibited reduced total chlorophyll, carotenoid, and relative water content compared to the control group, whereas the plants that were pre-treated with SA exhibited relatively higher values for the same physiological parameters. In the SA non-treated plants, the superoxide dismutase, glutathione reductase and glutathione S-transferase activities were increased in the treatment groups compared to the control group. In the treatment groups, these enzyme activities were decreased in the SA-pre-treated plants compared to the non-treated plants. Ascorbate peroxidase and catalase activities decreased in the flurochloridone-treated plants compared to the control plants. The ascorbate peroxidase activity increased in the control groups but decreased in the treatment groups in the SA pre-treated plants compared to the non-treated plants. However, SA treatment decreased the activity of catalase in the control and treatment groups compared to the plants that were not treated with SA. Flurochloridone treatment increased the malondialdehyde content in the treated groups compared to the control groups, whereas SA-pretreatment decreased malondialdehyde content compared to plants that were not treated with SA. Flurochloridone treatment increased endogenous SA content compared to the control. Although the residual levels of herbicide in the plants increased proportionately with increasing herbicide concentrations, the SA-pre-treated plants exhibited reduced residual herbicide levels compared to the plants that were not treated with SA. These results indicate that the flurochloridone induces various physiological and biochemical responses in non-target plants and that treatment with exogenous SA can increase stress resistance by altering these responses. Copyright © 2014 Elsevier Inc. All rights reserved.

[Alleviation of salt stress during maize seed germination by presoaking with exogenous sugar].

PubMed

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.

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

PubMed

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 extracts of LSP in oxidizing and removing from solution a series of last-generation dyes present in effluents from textile industries (1) had been checked, a steady-state kinetic study of the H(2)O(2)-mediated oxidation and decolorization of Green Domalan BL by the catalytic action of the lentil stubble extract was carried out, with the observation of the same apparent Michaelian kinetic behavior (K(m)(appGD) = 471 μM; V(max)(appGD)= 23 μM min(-1)). Further studies are currently under way to address the application of this LSP crude extract for the clinical and biochemical analysis of biomarkers.

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

PubMed

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.

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

PubMed

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.

Hydrogen peroxide production and mitochondrial dysfunction contribute to the fusaric acid-induced programmed cell death in tobacco cells.

PubMed

Jiao, Jiao; Sun, Ling; Zhou, Benguo; Gao, Zhengliang; Hao, Yu; Zhu, Xiaoping; Liang, Yuancun

2014-08-15

Fusaric acid (FA), a non-specific toxin produced mainly by Fusarium spp., can cause programmed cell death (PCD) in tobacco suspension cells. The mechanism underlying the FA-induced PCD was not well understood. In this study, we analyzed the roles of hydrogen peroxide (H2O2) and mitochondrial function in the FA-induced PCD. Tobacco suspension cells were treated with 100 μM FA and then analyzed for H2O2 accumulation and mitochondrial functions. Here we demonstrate that cells undergoing FA-induced PCD exhibited H2O2 production, lipid peroxidation, and a decrease of the catalase and ascorbate peroxidase activities. Pre-treatment of tobacco suspension cells with antioxidant ascorbic acid and NADPH oxidase inhibitor diphenyl iodonium significantly reduced the rate of FA-induced cell death as well as the caspase-3-like protease activity. Moreover, FA treatment of tobacco cells decreased the mitochondrial membrane potential and ATP content. Oligomycin and cyclosporine A, inhibitors of the mitochondrial ATP synthase and the mitochondrial permeability transition pore, respectively, could also reduce the rate of FA-induced cell death significantly. Taken together, the results presented in this paper demonstrate that H2O2 accumulation and mitochondrial dysfunction are the crucial events during the FA-induced PCD in tobacco suspension cells. Copyright © 2014 Elsevier GmbH. All rights reserved.

Hydrogen Sulfide Alleviates Postharvest Senescence of Grape by Modulating the Antioxidant Defenses

PubMed Central

Ni, Zhi-Jing; Hu, Kang-Di; Song, Chang-Bing; Ma, Run-Hui; Li, Zhi-Rong; Zheng, Ji-Lian; Fu, Liu-Hui

2016-01-01

Hydrogen sulfide (H2S) has been identified as an important gaseous signal in plants. Here, we investigated the mechanism of H2S in alleviating postharvest senescence and rotting of Kyoho grape. Exogenous application of H2S released from 1.0 mM NaHS remarkably decreased the rotting and threshing rate of grape berries. H2S application also prevented the weight loss in grape clusters and inhibited the decreases in firmness, soluble solids, and titratable acidity in grape pulp during postharvest storage. The data of chlorophyll and carotenoid content suggested the role of H2S in preventing chlorophyll breakdown and carotenoid accumulation in both grape rachis and pulp. In comparison to water control, exogenous H2S application maintained significantly higher levels of ascorbic acid and flavonoid and total phenolics and reducing sugar and soluble protein in grape pulp. Meanwhile, H2S significantly reduced the accumulation of malondialdehyde (MDA), hydrogen peroxide (H2O2), and superoxide anion (O2 ∙−) in grape pulp. Further investigations showed that H2S enhanced the activities of antioxidant enzymes ascorbate peroxidase (APX) and catalase (CAT) and decreased those of lipoxygenase (LOX) in both grape peels and pulp. In all, we provided strong evidence that H2S effectively alleviated postharvest senescence and rotting of Kyoho grape by modulating antioxidant enzymes and attenuating lipid peroxidation. PMID:27594971

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

PubMed Central

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

Effects of salinity on the growth, physiology and relevant gene expression of an annual halophyte grown from heteromorphic seeds

PubMed Central

Cao, Jing; Lv, Xiu Yun; Chen, Ling; Xing, Jia Jia; Lan, Hai Yan

2015-01-01

Seed heteromorphism provides plants with alternative strategies for survival in unfavourable environments. However, the response of descendants from heteromorphic seeds to stress has not been well documented. Suaeda aralocaspica is a typical annual halophyte, which produces heteromorphic seeds with disparate forms and different germination characteristics. To gain an understanding of the salt tolerance of descendants and the impact of seed heteromorphism on progeny of this species, we performed a series of experiments to investigate the plant growth and physiological parameters (e.g. osmolytes, oxidative/antioxidative agents and enzymes), as well as expression patterns of corresponding genes. Results showed that osmolytes (proline and glycinebetaine) were significantly increased and that excess reactive oxygen species (O2−, H2O2) produced under high salinity were scavenged by increased levels of antioxidant enzymes (superoxide dismutase, ascorbate peroxidase and glutathione reductase) and corresponding antioxidants (ascorbic acid and glutathione). Moreover, enhancement of phosphoenolpyruvate carboxylase activity at high salt intensity had a positive effect on photosynthesis. The descendants from heteromorphic seeds presented no significant difference in performance with or without salinity. In conclusion, we found that high salinity induced the same active physiological responses in plants from heteromorphic seeds of S. aralocaspica, there was no carry-over of seed heteromorphism to plants: all the descendants required salinity for optimal growth and adaptation to their natural habitat. PMID:26386128

Recent insights into antioxidant defenses of legume root nodules.

PubMed

Becana, Manuel; Matamoros, Manuel A; Udvardi, Michael; Dalton, David A

2010-12-01

Legume root nodules are sites of intense biochemical activity and consequently are at high risk of damage as a result of the generation of reactive oxygen species (ROS) and reactive nitrogen species (RNS). These molecules can potentially give rise to oxidative and nitrosative damage but, when their concentrations are tightly controlled by antioxidant enzymes and metabolites, they also play positive roles as critical components of signal transduction cascades during nodule development and stress. Thus, recent advances in our understanding of ascorbate and (homo)glutathione biosynthesis in plants have opened up the possibility of enhancing N(2) fixation through an increase of their concentrations in nodules. It is now evident that antioxidant proteins other than the ascorbate-glutathione enzymes, such as some isoforms of glutathione peroxidases, thioredoxins, peroxiredoxins, and glutathione S-transferases, are also critical for nodule activity. To avoid cellular damage, nodules are endowed with several mechanisms for sequestration of Fenton-active metals (nicotianamine, phytochelatins, and metallothioneins) and for controlling ROS/RNS bioactivity (hemoglobins). The use of 'omic' technologies has expanded the list of known antioxidants in plants and nodules that participate in ROS/RNS/antioxidant signaling networks, although aspects of developmental variation and subcellular localization of these networks remain to be elucidated. To this end, a critical point will be to define the transcriptional and post-transcriptional regulation of antioxidant proteins. © 2010 The Authors. New Phytologist © 2010 New Phytologist Trust.

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

PubMed Central

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

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

PubMed

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.

Ultrastructural localisation of protein interactions using conditionally stable nanobodies.

PubMed

Ariotti, Nicholas; Rae, James; Giles, Nichole; Martel, Nick; Sierecki, Emma; Gambin, Yann; Hall, Thomas E; Parton, Robert G

2018-04-01

We describe the development and application of a suite of modular tools for high-resolution detection of proteins and intracellular protein complexes by electron microscopy (EM). Conditionally stable GFP- and mCherry-binding nanobodies (termed csGBP and csChBP, respectively) are characterized using a cell-free expression and analysis system and subsequently fused to an ascorbate peroxidase (APEX) enzyme. Expression of these cassettes alongside fluorescently labelled proteins results in recruitment and stabilisation of APEX, whereas unbound APEX nanobodies are efficiently degraded by the proteasome. This greatly simplifies correlative analyses, enables detection of less-abundant proteins, and eliminates the need to balance expression levels between fluorescently labelled and APEX nanobody proteins. Furthermore, we demonstrate the application of this system to bimolecular complementation ('EM split-fluorescent protein'), for localisation of protein-protein interactions at the ultrastructural level.

Ultrastructural localisation of protein interactions using conditionally stable nanobodies

PubMed Central

Ariotti, Nicholas; Rae, James; Giles, Nichole; Martel, Nick; Sierecki, Emma; Gambin, Yann; Parton, Robert G.

2018-01-01

We describe the development and application of a suite of modular tools for high-resolution detection of proteins and intracellular protein complexes by electron microscopy (EM). Conditionally stable GFP- and mCherry-binding nanobodies (termed csGBP and csChBP, respectively) are characterized using a cell-free expression and analysis system and subsequently fused to an ascorbate peroxidase (APEX) enzyme. Expression of these cassettes alongside fluorescently labelled proteins results in recruitment and stabilisation of APEX, whereas unbound APEX nanobodies are efficiently degraded by the proteasome. This greatly simplifies correlative analyses, enables detection of less-abundant proteins, and eliminates the need to balance expression levels between fluorescently labelled and APEX nanobody proteins. Furthermore, we demonstrate the application of this system to bimolecular complementation (‘EM split-fluorescent protein’), for localisation of protein–protein interactions at the ultrastructural level. PMID:29621251

Light qualities and dose influence ascorbate pool size in detached oat leaves.

PubMed

Mastropasqua, Linda; Borraccino, Giuseppe; Bianco, Laura; Paciolla, Costantino

2012-02-01

In this work, we studied the mechanism of light influence on AsA pool size in Avena sativa L. under the effects of low intensity light at different wavelengths. Exposure to low intensity light of oat leaf segments incubated in water or in l-galactono-1,4-lactone (GL), resulted in an increase in AsA content compared with the dark control. This increase was due to modulation of l-galactono-1,4-lactone dehydrogenase (GLDH; EC 1.3.2.3) light-dependent activity and was dependent on the size of the endogenous GL pool. Both blue and red light were effective in increasing AsA, and this increase depended on both exposure time and light intensity. Protein biosynthesis, photosynthesis and calcium were involved in controlling the level of light-dependent AsA. We suggest that multiple checkpoints correlated to the presence of light underlie the ascorbate pool size. The presence of a light-activated switch for the maintenance of an adequate AsA level seems to be necessary for the various tasks of scavenging reactive oxygen species, in response to the dark-light cycle which plants experience under natural conditions. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

Alleviation of lead-induced physiological, metabolic, and ultramorphological changes in leaves of upland cotton through glutathione.

PubMed

Khan, Mumtaz; Daud, M K; Basharat, Ali; Khan, Muhammad Jamil; Azizullah, Azizullah; Muhammad, Niaz; Muhammad, Noor; Ur Rehman, Zia; Zhu, Shui Jin

2016-05-01

Plants face changes in leaves under lead (Pb) toxicity. Reduced glutathione (GSH) has several functions in plant metabolism, but its role in alleviating Pb toxicity in cotton leaves is still unknown. In the present study, cotton seedlings (28 days old) were exposed to 500 μM Pb and 50 μM GSH, both alone and in combination, for a period of 10 days, in the Hoagland solution under controlled growth conditions. Results revealed Pb-induced changes in cotton's leaf morphology, photosynthesis, and oxidative metabolism. However, exogenous application of GSH restored leaf growth. GSH triggered build up of chlorophyll a, chlorophyll b, and carotenoid contents and boosted fluorescence ratios (F v/F m and F v/F 0). Moreover, GSH reduced the malondialdehyde (MDA), hydrogen peroxide (H2O2), and Pb contents in cotton leaves. Results further revealed that total soluble protein contents were decreased under Pb toxicity; however, exogenously applied GSH improved these contents in cotton leaves. Activities of antioxidant enzymes (catalase (CAT), superoxide dismutase (SOD), peroxidase (POD), glutathione reductase (GR), and ascorbate peroxidase (APX)) were also increased by GSH application under Pb toxicity. Microscopic analysis showed that excess Pb shattered thylakoid membranes in chloroplasts. However, GSH stabilized ultrastructure of Pb-stressed cotton leaves. These findings suggested that exogenously applied GSH lessened the adverse effects of Pb and improved cotton's tolerance to oxidative stress.

Exogenous calcium induces tolerance to atrazine stress in Pennisetum seedlings and promotes photosynthetic activity, antioxidant enzymes and psbA gene transcripts.

PubMed

Erinle, Kehinde Olajide; Jiang, Zhao; Ma, Bingbing; Li, Jinmei; Chen, Yukun; Ur-Rehman, Khalil; Shahla, Andleeb; Zhang, Ying

2016-10-01

Calcium (Ca) has been reported to lessen oxidative damages in plants by upregulating the activities of antioxidant enzymes. However, atrazine mediated reactive oxygen species (ROS) reduction by Ca is limited. This study therefore investigated the effect of exogenously applied Ca on ROS, antioxidants activity and gene transcripts, the D1 protein (psbA gene), and chlorophyll contents in Pennisetum seedlings pre-treated with atrazine. Atrazine toxicity increased ROS production and enzyme activities (ascorbate peroxidase APX, peroxidase POD, Superoxide dismutase SOD, glutathione-S-transferase GST); but decreased antioxidants (APX, POD, and Cu/Zn SOD) and psbA gene transcripts. Atrazine also decreased the chlorophyll contents, but increased chlorophyll (a/b) ratio. Contrarily, Ca application to atrazine pre-treated seedlings lowered the harmful effects of atrazine by reducing ROS levels, but enhancing the accumulation of total chlorophyll contents. Ca-protected seedlings in the presence of atrazine manifested reduced APX and POD activity, whereas SOD and GST activity was further increased with Ca application. Antioxidant gene transcripts that were down-regulated by atrazine toxicity were up-regulated with the application of Ca. Calcium application also resulted in up-regulation of the D1 protein. In conclusion, ability of calcium to reverse atrazine-induced oxidative damage and calcium regulatory role on GST in Pennisetum was presented. Copyright © 2016 Elsevier Inc. All rights reserved.

Up-regulation of antioxidants in tobacco by low concentrations of H₂O₂ suppresses necrotic disease symptoms.

PubMed

Hafez, Yaser Mohamed; Bacsó, Renáta; Király, Zoltán; Künstler, András; Király, Lóránt

2012-09-01

Pretreatment of tobacco leaves with low concentrations (5 to 10 mM) of H₂O₂ suppressed hypersensitive-type necrosis associated with resistance to Tobacco mosaic virus (TMV) or Pseudomonas syringae pv. phaseolicola. The same pretreatment resulted in suppression of normosensitive necrosis associated with susceptibility to Botrytis cinerea. This type of H₂O₂-mediated, induced disease symptom resistance correlated with enhanced host antioxidant capacity, i.e., elevated enzymatic activities of catalase (CAT), ascorbate peroxidase (APX), and guaiacol peroxidase (POX) after viral and bacterial infections. Induction of genes that encode the antioxidants superoxide dismutase (SOD), CAT, and APX was also enhanced early after TMV infection. Artificial application of SOD and CAT suppressed necroses caused by viral, bacterial, or fungal pathogens similarly as H₂O₂ pretreatment, implying that H₂O₂-mediated symptom resistance operates through enhancement of plant antioxidant capacity. Pathogen multiplication was not significantly affected in H₂O₂-pretreated plants. Salicylic acid (SA), a central component of plant defense, does not seem to function in this type of H₂O₂-mediated symptom resistance, indicated by unchanged levels of free and bound SA and a lack of early up-regulation of an SA glucosyltransferase gene in TMV-infected H₂O₂-pretreated tobacco. Taken together, H₂O₂-mediated, induced resistance to necrotic symptoms in tobacco seems to depend on enhanced antioxidant capacity.

Green Synthesized Zinc Oxide (ZnO) Nanoparticles Induce Oxidative Stress and DNA Damage in Lathyrus sativus L. Root Bioassay System.

PubMed

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.

Antioxidation activities of pteridines in mammalian cell lines

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Y.; Shen, R.

1991-03-11

L-erythro-5,6,7,8-Tetrahydrobiopterin (BH{sub 4}), the cofactor for aromatic amino acid hydroxylases (AAA-H), is a predominant form of pteridines which occur ubiquitously in nature. When BH{sub 4} is oxidized to quinonoid dihydrobiopterin by AAA-H, it is regenerated by dihydropteridine reductase (DHPR) at the expense of NADH. The role of BH{sub 4} other than serving as the hydroxylase cofactor is not clear. The existence of BH{sub 4} and DHPR in tissues which are devoid of AAA-H suggests that BH{sub 4} may play an as yet undiscovered physiological function. This study demonstrates a BH{sub 4}-mediated antioxidation system, which consists of BH{sub 4}, DHPR, peroxidasemore » and NADH in rat pheochromocytoma PC 12 cells and mouse macrophages J774A.1. This system was as effective as catalase and ascorbic acid in protecting cells against H{sub 2}O{sub 2} and xanthine/xanthine oxidase-induced toxicity and was more effective than catalase in defense against nitrofurantoin-induced toxicity. The antioxidation effect of this system was not due to peroxidase and was improved when synthetic pteridines were substituted for BH{sub 4}. Since BH{sub 4}, DHPR, peroxidases and NADH are widely distributed in major organs and blood cells, they may constitute an as yet little known antioxidation system in mammalian cells.« less

The effects of chronic radiation of gamma ray on protein expression and oxidative stress in Brachypodium distachyon.

PubMed

Kim, Dae Yeon; Hong, Min Jeong; Park, Cheong-Sool; Seo, Yong Weon

2015-05-01

To compare the effects of gamma-irradiation on biochemical responses and growth, six-week-old Brachypodium plants were chronically exposed to gamma-irradiation for 30 days at various dosages. Growth surveys of Brachypodium plants in response to different dosages of gamma-irradiation were conducted to compare physiological changes between irradiated and non-irradiated plants. Photosynthetic pigments, soluble sugar content, activities of antioxidant enzymes, and malonaldehyde (MDA) induced by reactive oxygen species (ROS) production were also measured. Gamma-irradiation had a negative influence on the average plant height, leaf length, leaf width, and fresh weight. Photosynthetic pigment levels decreased with increasing dosages of gamma-irradiation, while soluble sugar content slightly increased. Gamma-irradiation responsive proteins were detected and identified by two-dimensional gel electrophoresis (2D-PAGE) and matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF). The proteins had a role in photosynthetic carbon fixation, anabolic pathway glycolysis, mitochondrial ATP production, and oxidative stress response regulation. MDA levels and activities of antioxidant enzymes such as superoxide dismutase (SOD), ascorbate peroxidase (APX), catalase (CAT), and peroxidase (POD) increased with the increase in gamma-irradiation dosage level. This study provides some basic information regarding responses to gamma-irradiation, and provides valuable physiological and biological data on the effects of different gamma-irradiation dosages on Triticeae species.

Removing Arsenic and Antimony by Phragmites australis: Rhizofiltration Technology

NASA Astrophysics Data System (ADS)

Ghassemzadeh, F.; Yousefzadeh, H.; Arbab-Zavar, M. H.

Arsenic (As) and Antimony (Sb) are toxic heavy metals that often associated in contaminated environment. High As concentration is reported in Chelpo, Khorasan province, northeast Iran. This study examined the possibility of As and Sb in rhizofiltration by common reed, Phragmites australis. Plants collected from five sampling sites of Chelpo. As and Sb concentrations in roots and shoots were determined by Atomic absorption spectrometry. About 80% of total As accumulated in roots than shoot system. Maximum As and Sb accumulation in root and rhizomes were 84.5-16.20 and 73-10.20 ppb, respectively. As/Sb ratio of root and rhizome ranged from 35 to 194 and 10.42 to 99.9, respectively. Arsenic contents in roots of contaminated plants were significantly higher than antimony accumulation (p<0.01). There was antagonistic interaction between As, Sb with P contents in the roots of contaminated plants. Common reed establishment may be locally enhanced by significantly decreased phosphorous (1.79 and 1.18 times less than control plant root and rhizome), increased Iron (1.42 and 5.83 times more than control plant root and rhizome) Enzymatic antioxidants (Catalase, Ascorbate peroxidase and Guaicol peroxidase) increased significantly with increment of As uptake in root system. Root As and Sb accumulation with enhanced changes in metabolic changes indicates that P. australis could be used as As, Sb rhizofiltration agent in this region and similar contaminated area.

Modulation of oxidative responses by a virulent isolate of Colletotrichum fructicola in apple leaves.

PubMed

Velho, Aline Cristina; Rockenbach, Mathias F; Mondino, Pedro; Stadnik, Marciel J

2016-10-01

Apple bitter rot (ABR) and Glomerella leaf spot (GLS) can be caused by Colletotrichum fructicola. Although both diseases can occur simultaneously in orchards, some isolates show clear organ specialization. Thus, this work was aimed to compare microscopically the development of preinfective structures of ABR- and GLS isolates and their impact on the enzymatic oxidant defense system during the leaf infection process. On leaves, conidial germlings of GLS-isolate formed appressoria mostly sessile. In contrast, those of ABR-isolate were pedicellate and formed multiple melanized appressoria probably as a sign of unsuccessful infection attempts. Neither ABR- nor GLS isolate triggered hypersensitive response in apple leaves. In overall, the activity of scavenging enzymes was higher and long-lasting in leaves inoculated by GLS- than by ABR isolate and control. Guaiacol peroxidase, catalase, and glutathione reductase had activity peaks within 24 h after inoculation (HAI). Ascorbate peroxidase activity was higher only in GLS-infected leaves at 6 HAI, while superoxide dismutase remained unaltered. A lower level of hydrogen peroxide (H2O2) was determined in GLS-infected plants at 48 HAI, but the electrolyte leakage markedly increased. Disease symptoms in leaves were only caused by GLS-isolate. Results suggest that the virulent isolate coordinately downregulates the oxidative plant defense responses enabling its successful establishment in apple leaves. Copyright © 2016 British Mycological Society. Published by Elsevier Ltd. All rights reserved.

Seed priming with KNO3 mediates biochemical processes to inhibit lead toxicity in maize (Zea mays L.).

PubMed

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.

Biological responses of wheat (Triticum aestivum) plants to the herbicide simetryne in soils.

PubMed

Jiang, Lei; Yang, Yi; Jia, Lin Xian; Lin, Jing Ling; Liu, Ying; Pan, Bo; Lin, Yong

2016-05-01

The rotation of rice and wheat is widely used and highly endorsed, and simetryne (s-triazine herbicide) is one of the principal herbicides widely used in this rotation for weed and grass control. However, little is known regarding the mechanism of the ecological and physiological effects of simetryne on wheat crops. In this study, we performed a comprehensive investigation of crop response to simetryne to elucidate the accumulation and phytotoxicity of the herbicide in wheat crops. Wheat plants exposed to 0.8 to 8.0mgkg(-1) simetryne for 7 d exhibited suppressed growth and decreased chlorophyll content. With simetryne concentration in the soil varied from 0.8mgkg(-1) to 8.0mgkg(-1), simetryne was progressively accumulated by the wheat plants. The accumulation of simetryne in the wheat plants not only induced the over production of ROS and injured the membrane lipids but also stimulated the production of antioxidant enzymes, including superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), ascorbate peroxidase (APX), glutathione reductase (GR) and glutathione S-transferase (GST). A test of enzymatic activity and gene expression illustrated that the wheat plants were wise enough to motivate the antioxidant enzymes through both molecular and physiological mechanisms to alleviate the simetryne-induced stress. This study offers an illuminating insight into the effective adaptive response of the wheat plants to the simetryne stress. Copyright © 2016 Elsevier Inc. All rights reserved.

Exogenous salicylic acid alleviates the toxicity of chlorpyrifos in wheat plants (Triticum aestivum).

PubMed

Wang, Caixia; Zhang, Qingming

2017-03-01

The role of exogenous salicylic acid (SA) in protecting wheat plants (Triticum aestivum) from contamination by the insecticide chlorpyrifos was investigated in this study. The wheat plants were grown in soils with different concentrations (5, 10, 20, and 40mgkg -1 ) of chlorpyrifos. When the third leaf emerged, the wheat leaves were sprayed with 1, 2, 4, 8, and 16mgL -1 of SA once a day for 6 days. The results showed that wheat exposed to higher concentrations of chlorpyrifos (≥20mgkg -1 ) caused declines in growth and chlorophyll content and altered the activities of a series of antioxidant enzymes including superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), and ascorbate peroxidase (APX). Interestingly, treatments with different concentrations of SA mitigated the stress generated by chlorpyrifos and improved the measured parameters to varying degrees. Furthermore, a reverse transcription and quantitative PCR experiment revealed that the activities of SOD and CAT can be regulated by their target gene in wheat when treated with SA. We also found that SA is able to block the accumulation of chlorpyrifos in wheat. However, the effect of SA was related to its concentration. In this study, the application of 2mgL -1 of SA had the greatest ameliorating effect on chlorpyrifos toxicity in wheat plants. Copyright © 2016 Elsevier Inc. All rights reserved.

Comparative proteomic analyses reveal the proteome response to short-term drought in Italian ryegrass (Lolium multiflorum)

PubMed Central

Wang, Jianping; Wang, Pengxi; Ma, Xiao; Zhou, Meiliang; Li, Ji; Gang, Nie; Feng, Guangyan; Zhao, Junming

2017-01-01

Drought is a major abiotic stress that impairs growth and productivity of Italian ryegrass. Comparative analysis of drought responsive proteins will provide insight into molecular mechanism in Lolium multiflorum drought tolerance. Using the iTRAQ-based approach, proteomic changes in tolerant and susceptible lines were examined in response to drought condition. A total of 950 differentially accumulated proteins was found to be involved in carbohydrate metabolism, amino acid metabolism, biosynthesis of secondary metabolites, and signal transduction pathway, such as β-D-xylosidase, β-D-glucan glucohydrolase, glycerate dehydrogenase, Cobalamin-independent methionine synthase, glutamine synthetase 1a, Farnesyl pyrophosphate synthase, diacylglycerol, and inositol 1, 4, 5-trisphosphate, which might contributed to enhance drought tolerance or adaption in Lolium multiflorum. Interestingly, the two specific metabolic pathways, arachidonic acid and inositol phosphate metabolism including differentially accumulated proteins, were observed only in the tolerant lines. Cysteine protease cathepsin B, Cysteine proteinase, lipid transfer protein and Aquaporin were observed as drought-regulated proteins participating in hydrolysis and transmembrane transport. The activities of phospholipid hydroperoxide glutathione peroxidase, peroxiredoxin, dehydroascorbate reductase, peroxisomal ascorbate peroxidase and monodehydroascorbate reductase associated with alleviating the accumulation of reactive oxygen species in stress inducing environments. Our results showed that drought-responsive proteins were closely related to metabolic processes including signal transduction, antioxidant defenses, hydrolysis, and transmembrane transport. PMID:28910323

Evaluation of anti-fatigue property of the extruded product of cereal grains mixed with Cordyceps militaris on mice.

PubMed

Zhong, Lei; Zhao, Liyan; Yang, Fangmei; Yang, Wenjian; Sun, Yong; Hu, Qiuhui

2017-01-01

Fatigue is a biological phenomenon that involves a feeling of extreme physical or mental tiredness that could potentially cause some severe chronic diseases. Recently, diet therapy has provided a new alternative to alleviate physical fatigue. In our previous study, addition of Cordyceps militaris ( C. militaris ) into an extruded product was shown to provide high nutrition and unique flavors; however, little is known whether this product has some scientific evidence regarding anti-fatigue property. The purpose of this study was to evaluate the anti-fatigue effects of extruded products of cereal grains (EC) and EC mixed with C. militaris (ECC). The mice were divided into seven groups: one group received distilled water (Control group, n  = 20), and the other groups received different dosages of EC (5, 10 and 20 g/kg body weight, n  = 20 per group) or of ECC (5, 10 and 20 g/kg body weight, n  = 20 per group) solution in water. All of the mice were administered with distilled water, EC or ECC continuously for 30 days by gavage and the anti-fatigue activity was evaluated using a weight-loaded swimming test, along with assessments of fatigue-related indicators. The mode of fighting fatigue was investigated by determining changes in exercise endurance and biochemical markers, including exhaustive swimming time, lactate dehydrogenase (LDH), blood lactic acid (BLA), creatine kinase (CK), blood urea nitrogen (BUN), malondialdehyde (MDA), glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), catalase (CAT), and hepatic and muscle glycogen levels. EC and ECC prolonged the swimming endurance time of mice compared to the control. The content of BLA at high dose of ECC group (20 g/kg) was significantly lower than that in the negative control group. CK, BUN and MDA levels were significantly reduced by treatment with EC and ECC compared to the negative control, while the low and middle dose of EC had no significant effect on MDA levels. Additionally, only the middle and high dose of EC (10, 20 g/kg) could significantly decrease the BUN level. EC and ECC treatments increased glycogen, LDH, SOD, CAT and GSH-Px levels. Low and middle dose of EC had no significant effects on muscle glycogen. Moreover, low dose of EC could increase the level of SOD but it was not statistically significant. Compared to the EC treatment groups, ECC demonstrated the efficacy of anti-fatigue potential, particularly at a high dose of ECC, the best performance in relieving fatigue. These results suggest that EC and ECC could prevent exercise-induced fatigue in mice and ECC provided a better effect. In addition, C. militaris in ECC might play a crucial role in the anti-fatigue activity of ECC.

Glutathione homeostasis as an important and novel factor controlling blossom-end rot development in calcium-deficient tomato fruits.

PubMed

Mestre, Teresa C; Garcia-Sanchez, Francisco; Rubio, Francisco; Martinez, Vicente; Rivero, Rosa M

2012-11-15

Based on previous results in which oxidative metabolism was suggested as a possible inducer of blossom-end rot (BER), the main questions addressed here were whether calcium deficiency is the main factor that induces BER or whether this physiological disorder a general stress-related phenomenon? Tomato plants were grown under optimal or deficient calcium concentrations. Only the application of 0.1mM calcium resulted in BER induction, although only half of the fruits grown under this treatment had this disorder. Having fruits showing or not showing BER in the same plant and treatment provided us with a powerful tool that we used to investigate whether calcium deficiency operates alongside another mechanism in the induction of BER. Whether or not this other mechanism was the one controlling BER incidence was also investigated. We performed a complete study of the oxidative metabolism in the pericarp of healthy fruits and in the healthy portion of BER-affected fruits. Calcium deficiency led to an induction of NADPH oxidase, superoxide dismutase, dehydro- and monodehydroascorbate reductase, and to an inhibition of catalase, ascorbate peroxidase and glutathione reductase, with a concomitant accumulation of hydrogen peroxide and an increase in lipid peroxidation. While the ascorbate redox state was not affected by calcium deficiency, the glutathione redox state was markedly reduced. We conclude that calcium deficiency fundamentally affected the activity of the ascorbate-glutathione enzymes, with special importance to the inhibition of GR, which lead to a reduction of the glutathione redox state. This could cause the breakdown of cellular homeostasis, the inhibition of other enzymes responsible for H(2)O(2) detoxification, and ultimately an increase of lipid peroxidation. Therefore, BER is defined here as the visual symptom of a massive lipid peroxidation event caused by the breakdown of cellular glutathione homeostasis. Copyright © 2012 Elsevier GmbH. All rights reserved.

Involvement of polyamine oxidase in abscisic acid-induced cytosolic antioxidant defense in leaves of maize.

PubMed

Xue, Beibei; Zhang, Aying; Jiang, Mingyi

2009-03-01

Using pharmacological and biochemical approaches, the role of maize polyamine oxidase (MPAO) in abscisic acid (ABA)-induced antioxidant defense in leaves of maize (Zea mays L.) plants was investigated. Exogenous ABA treatment enhanced the expression of the MPAO gene and the activities of apoplastic MPAO. Pretreatment with two different inhibitors for apoplastic MPAO partly reduced hydrogen peroxide (H2O2) accumulation induced by ABA and blocked the ABA-induced expression of the antioxidant genes superoxide dismutase 4 and cytosolic ascorbate peroxidase and the activities of the cytosolic antioxidant enzymes. Treatment with spermidine, the optimum substrate of MPAO, also induced the expression and the activities of the antioxidant enzymes, and the upregulation of the antioxidant enzymes was prevented by two inhibitors of MPAO and two scavengers of H2O2. These results suggest that MPAO contributes to ABA-induced cytosolic antioxidant defense through H2O2, a Spd catabolic product.

Enzymatic Spectrophotometric Reaction Rate Determination of Glucose in Fruit Drinks and Carbonated Beverages. An Analytical Chemistry Laboratory Experiment for Food Science-Oriented Students

NASA Astrophysics Data System (ADS)

Vasilarou, Argyro-Maria G.; Georgiou, Constantinos A.

2000-10-01

The glucose oxidase-horseradish peroxidase coupled reaction using phenol and 4-aminoantipyrine is used for the kinetic determination of glucose in drinks and beverages. This laboratory experiment demonstrates the implementation of reaction rate kinetic methods of analysis, the use of enzymes as selective analytical reagents for the determination of substrates, the kinetic masking of ascorbic acid interference, and the analysis of glucose in drinks and beverages. The method is optimized for student use in the temperature range of 18-28 °C and can be used in low-budget laboratories equipped with an inexpensive visible photometer. The mixed enzyme-chromogen solution that is used is stable for two months. Precision ranged from 5.1 to 12% RSD for analyses conducted during a period of two months by 48 students.

Effect of high power low frequency ultrasound processing on the stability of lycopene.

PubMed

Oliveira, Valéria S; Rodrigues, Sueli; Fernandes, Fabiano A N

2015-11-01

The stability of lycopene was evaluated after application of high power low frequency ultrasound. The study was carried out on a solution containing pure lycopene to evaluate the direct effect of ultrasound on lycopene and on tomato purée to evaluate the direct and indirect effects of ultrasound application within a food matrix. Power densities ranging from 55 to 5000 W/L and temperatures ranging from 23°C (ambient) to 60°C were evaluated. The experiments on pure lycopene showed that the application of ultrasound did not have any direct effect over lycopene. However, the retention of lycopene in tomato puree has decreased indicating an indirect effect on lycopene stability caused by high concentration of hydrogen peroxide and the activation of peroxidase enzymes leading to the reduction of ascorbic acid and its regenerative action towards lycopene. Copyright © 2015 Elsevier B.V. All rights reserved.

Differential Responses of Polyamines and Antioxidants to Drought in a Centipedegrass Mutant in Comparison to Its Wild Type Plants

PubMed Central

Liu, Mingxi; Chen, Jingjing; Guo, Zhenfei; Lu, Shaoyun

2017-01-01

Centipedegrass (Eremochloa ophiuroides [Munro] Hack.) is an important warm-season turfgrass species with low turf maintenance requirements. However, our knowledge on physiological adaptation of centipedegrass to drought stress is limited. Physiological responses to drought in a gamma-ray-induced mutant 22-1 as compared with two wild type (WT) lines were analyzed for understanding of drought tolerance mechanism of centipedegrass. The mutant showed an elevated drought tolerance with higher levels of relative water content, net photosynthetic rate (A) and stomatal conductance (gs) and lower levels of ion leakage and malondialdehyde (MDA) under drought stress as compared with WT plants. A showed significant correlation with gs and MDA. Higher levels of antioxidant enzymes activities, non-enzyme antioxidants, and polyamines including putrescine (Put), spermidine (Spd), and spermine (Spm) were maintained in 22-1 than in WT plants. Superoxide dismutase (SOD), catalase (CAT), ascorbate-peroxidase (APX), and glutathione reductase (GR) activities and ascorbic acid (AsA) content were significantly correlated with both Put and Spd levels, and reduced glutathione level was correlated with Put during drought stress. Exogenous application of Put, Spd, and Spm increased drought tolerance and activities of SOD, CAT, APX, and GR in WT plants. The results suggest that higher levels of polyamines and antioxidant defense system are associated with the elevated drought tolerance in 22-1, which may improve protection on photosynthesis against drought induced oxidative damage. PMID:28559909

Nitric Oxide Ameliorates Zinc Oxide Nanoparticles Phytotoxicity in Wheat Seedlings: Implication of the Ascorbate–Glutathione Cycle

PubMed Central

Tripathi, Durgesh K.; Mishra, Rohit K.; Singh, Swati; Singh, Samiksha; Vishwakarma, Kanchan; Sharma, Shivesh; Singh, Vijay P.; Singh, Prashant K.; Prasad, Sheo M.; Dubey, Nawal K.; Pandey, Avinash C.; Sahi, Shivendra; Chauhan, Devendra K.

2017-01-01

The present study investigates ameliorative effects of nitric oxide (NO) against zinc oxide nanoparticles (ZnONPs) phytotoxicity in wheat seedlings. ZnONPs exposure hampered growth of wheat seedlings, which coincided with reduced photosynthetic efficiency (Fv/Fm and qP), due to increased accumulation of zinc (Zn) in xylem and phloem saps. However, SNP supplementation partially mitigated the ZnONPs-mediated toxicity through the modulation of photosynthetic activity and Zn accumulation in xylem and phloem saps. Further, the results reveal that ZnONPs treatments enhanced levels of hydrogen peroxide and lipid peroxidation (as malondialdehyde; MDA) due to severely inhibited activities of the following ascorbate–glutatione cycle (AsA–GSH) enzymes: ascorbate peroxidase, glutathione reductase, monodehydroascorbate reductase and dehydroascorbate reductase, and its associated metabolites ascorbate and glutathione. In contrast to this, the addition of SNP together with ZnONPs maintained the cellular functioning of the AsA–GSH cycle properly, hence lesser damage was noticed in comparison to ZnONPs treatments alone. The protective effect of SNP against ZnONPs toxicity on fresh weight (growth) can be reversed by 2-(4carboxy-2-phenyl)-4,4,5,5-tetramethyl- imidazoline-1-oxyl-3-oxide, a NO scavenger, and thus suggesting that NO released from SNP ameliorates ZnONPs toxicity. Overall, the results of the present study have shown the role of NO in the reducing of ZnONPs toxicity through the regulation of accumulation of Zn as well as the functioning of the AsA–GSH cycle. PMID:28220127

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.

PubMed

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.

Exogenous Proline and Glycine Betaine Mediated Upregulation of Antioxidant Defense and Glyoxalase Systems Provides Better Protection against Salt-Induced Oxidative Stress in Two Rice (Oryza sativa L.) Varieties

PubMed Central

Hasanuzzaman, Mirza; Alam, Md. Mahabub; Rahman, Anisur; Hasanuzzaman, Md.; Nahar, Kamrun; Fujita, Masayuki

2014-01-01

The present study investigates the roles of exogenous proline (Pro, 5 mM) and glycine betaine (GB, 5 mM) in improving salt stress tolerance in salt sensitive (BRRI dhan49) and salt tolerant (BRRI dhan54) rice (Oryza sativa L.) varieties. Salt stresses (150 and 300 mM NaCl for 48 h) significantly reduced leaf relative water (RWC) and chlorophyll (chl) content and increased endogenous Pro and increased lipid peroxidation and H2O2 levels. Ascorbate (AsA), glutathione (GSH) and GSH/GSSG, ascorbate peroxidae (APX), monodehydroascorbate reductase (MDHAR), dehydroascorbate reductase (DHAR), glutathione reductase (GR), glutathione peroxidase (GPX), catalase (CAT), and glyoxalase I (Gly I) activities were reduced in sensitive variety and these were increased in tolerant variety due to salt stress. The glyoxalase II (Gly II), glutathione S-transferase (GST), and superoxide dismutase (SOD) activities were increased in both cultivars by salt stress. Exogenous Pro and GB application with salt stress improved physiological parameters and reduced oxidative damage in both cultivars where BRRI dhan54 showed better tolerance. The result suggests that exogenous application of Pro and GB increased rice seedlings' tolerance to salt-induced oxidative damage by upregulating their antioxidant defense system where these protectants rendered better performance to BRRI dhan54 and Pro can be considered as better protectant than GB. PMID:24991566

Boron excess affects photosynthesis and antioxidant apparatus of greenhouse Cucurbita pepo and Cucumis sativus.

PubMed

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.

Silicon Regulates Antioxidant Activities of Crop Plants under Abiotic-Induced Oxidative Stress: A Review

PubMed Central

Kim, Yoon-Ha; Khan, Abdul L.; Waqas, Muhammad; Lee, In-Jung

2017-01-01

Silicon (Si) is the second most abundant element in soil, where its availability to plants can exhilarate to 10% of total dry weight of the plant. Si accumulation/transport occurs in the upward direction, and has been identified in several crop plants. Si application has been known to ameliorate plant growth and development during normal and stressful conditions over past two-decades. During abiotic (salinity, drought, thermal, and heavy metal etc) stress, one of the immediate responses by plant is the generation of reactive oxygen species (ROS), such as singlet oxygen (1O2), superoxide (O2−), hydrogen peroxide (H2O2), and hydroxyl radicals (OH), which cause severe damage to the cell structure, organelles, and functions. To alleviate and repair this damage, plants have developed a complex antioxidant system to maintain homeostasis through non-enzymatic (carotenoids, tocopherols, ascorbate, and glutathione) and enzymatic antioxidants [superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase (APX)]. To this end, the exogenous application of Si has been found to induce stress tolerance by regulating the generation of ROS, reducing electrolytic leakage, and malondialdehyde (MDA) contents, and immobilizing and reducing the uptake of toxic ions like Na, under stressful conditions. However, the interaction of Si and plant antioxidant enzyme system remains poorly understood, and further in-depth analyses at the transcriptomic level are needed to understand the mechanisms responsible for the Si-mediated regulation of stress responses. PMID:28428797

Toxic effects of lambda-cyhalothrin, a synthetic pyrethroid pesticide, on the rat kidney: Involvement of oxidative stress and protective role of ascorbic acid.

PubMed

Fetoui, Hamadi; Makni, Mohamed; Garoui, El Mouldi; Zeghal, Najiba

2010-11-01

Lambda-cyhalothrin is a synthetic pyrethroid insecticide used worldwide in agriculture, home pest control, protection of foodstuff and disease vector control. The objective of this study was to investigate the propensity of lambda-cyhalothrin (LTC) to induce oxidative stress, changes in biochemical parameters and enzyme activities in the kidney of male rats and its possible attenuation by Vitamin C (vit C). Renal function, histopathology, tissue malondialdehyde (MDA), protein carbonyl (PCO) levels, antioxidant enzyme activities and reduced glutathione (GSH) levels were evaluated. Exposure of rats to lambda-cyhalothrin, during 3 weeks, caused a significant increase in kidney MDA and protein carbonyl levels (p<0.01) as compared to controls. Co-administration of vitamin C was effective in reducing MDA and PCO levels. The kidney of LTC-treated rats exhibited severe vacuolations, cells infiltration and widened tubular lumen. The activities of catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione reductase (GR) and glutathione-S-transferase (GST) were significantly decreased due to lambda-cyhalothrin exposure. Co-administration of vitamin C ameliorated the increase in enzymatic activities of aminotransferases (AST and ALT), lactate dehydrogenase (LDH), creatinine and urea levels and improved the antioxidant status. These data indicated the protective role of ascorbic acid against lambda-cyhalothrin-induced nephrotoxicity and suggested a significant contribution of its antioxidant property to these beneficial effects. Copyright © 2009 Elsevier GmbH. All rights reserved.

[Antioxidants of Contracaecum rudolphii (Nematoda)].

PubMed

Zółtowska, Krystyna; Farjan, Marek; Lopieńska-Biernat, Elzbieta; Rokicki, Jerzy

2008-01-01

Contracaecum rudolphii is the parasitic nematode of fish-eating birds. In the extracts from female, male and larvae L3 and L4 isolated from the alimentary tracts of black cormorants the activity of five antioxidant enzymes: superoxide dismutase (SOD), glutathione peroxidase (GPX), glutathione transferase (GST), glutathione reductase (GR), catalase (CAT) and the content of ascorbate and total antioxidative status (TAS) were determined. They can be put in order according to the activity growth: GPX, SOD, GST, CAT and GR. The activity of GPX were very low in the nematodes' extracts (1.23-7.67 microU/mg). CAT had higher activity (0.47-0.72 U/mg). The activity of GR was the highest (50.51-69.88 U/mg). SOD activity in the female was higher by ca. 50% than in the male while GST activity was at similar levels. GR and CAT activities were higher by ca. 30% in the male than in the female nematodes. GST and GPX activity and TAS in larvae L3 were significantly lower than in the adult nematodes or in L4 larvae. The activity of GPX, GR and CAT was lower in L4 larvae than in the adult male (p<0.05). The content of ascorbate was almost the same in all stages of parasite development (0.21-0.38 mg/g). The above results indicate differences in antioxidant systems related to both the sex and the developmental stage of C. rudolphii.

Induced resistance by oxidative shifts in pigeonpea (Cajanus cajan L.) following Helicoverpa armigera (Hübner) herbivory.

PubMed

Kaur, Rimaljeet; Gupta, Anil K; Taggar, Gaurav K

2015-05-01

Oxidative responses in leaves, developing seeds and the pod wall of nine pigeonpea genotypes were investigated against Helicoverpa armigera feeding. Out of nine genotypes, four were moderately resistant, three were intermediate and two were moderately susceptible genotypes. A significant shift in the oxidative status of pigeonpea following herbivory was depicted by the upregulation of diamine oxidase (DAO), polyamine oxidase (PAO) and lipoxygenase 2 (LOX 2) activities. Polyphenol oxidase (PPO) activity was significantly higher in the infested pod wall and leaves of moderately resistant genotypes than in those of moderately susceptible genotypes. H. armigera infestation markedly enhanced phenylalanine ammonia lyase (PAL) and tyrosine ammonia lyase (TAL) activities in wounded tissues. The decline in ascorbate peroxidase (APX) activity and ascorbate content was lower in moderately resistant genotypes than in moderately susceptible genotypes. A significant decrease in LOX 3 activity was also observed in the infested pod wall of moderately resistant and intermediate genotypes. A lower malondialdehyde (MDA) content and higher proline content of the infested pod wall and developing seeds was observed. Higher activities of PPO, PAL and proline content in leaves of uninfested moderately resistant genotypes could either be an unrelated observation or alternatively could help in identifying H. armigera-resistant genotypes. The increase in activities of PPO, DAO, PAO, PAL and TAL and higher proline and lower MDA content upon herbivory suggested their integrated contribution in providing resistance to pigeonpea against H. armigera. © 2014 Society of Chemical Industry.

Effects of salt stress on the expression of antioxidant genes and proteins in the model legume Lotus japonicus.

PubMed

Rubio, Maria C; Bustos-Sanmamed, Pilar; Clemente, Maria R; Becana, Manuel

2009-03-01

Salt stress negatively affects many physiological processes in plants. Some of these effects may involve the oxidative damage of cellular components, which can be promoted by reactive oxygen species and prevented by antioxidants. The protective role of antioxidants was investigated in Lotus japonicus exposed to two salinization protocols: S1 (150 mM NaCl for 7 d) and S2 (50, 100 and 150 mM NaCl, each concentration for 6 d). Several markers of salt stress were measured and the expression of antioxidant genes was analyzed using quantitative reverse transcription–polymerase chain reaction and, in some cases, immunoblots and enzyme activity assays. Leaves of S1 plants suffered from mild osmotic stress, accumulated proline but noNa+, and showed induction of many superoxide dismutase and glutathione peroxidase genes. Leaves of S2 plants showed increases in Na+ and Ca2+, decreases in K+, and accumulation of proline and malondialdehyde. In leaves and roots of S1 and S2 plants, the mRNA, protein and activity levels of the ascorbate-glutathione enzymes remained constant, with a few exceptions. Notably, there was consistent up-regulation of the gene encoding cytosolic dehydroascorbate reductase, and this was possibly related to its role in ascorbate recycling in the apoplast. The overall results indicate that L. japonicus is more tolerant to salt stress than other legumes, which can be attributed to the capacity of the plant to prevent Na+reaching the shoot and to activate antioxidant defenses.

Synergistic effects of plant defense elicitors and Trichoderma harzianum on enhanced induction of antioxidant defense system in tomato against Fusarium wilt disease.

PubMed

Zehra, Andleeb; Meena, Mukesh; Dubey, Manish Kumar; Aamir, Mohd; Upadhyay, R S

2017-11-02

Plant defense against their pathogens can be induced by a complex network of different inducers. The present study investigates the synergistic effect of Trichoderma harzianum, exogenous salicylic acid (SA) and methyl jasmonate (MeJA) over the response and regulation of the antioxidant defense mechanisms and lipid peroxidation in tomato plants against Fusarium wilt disease. In the present work, tomato plants were infected by Fusarium oxysporum f. sp. lycopersici 3 days after inoculated with T. harzianum and/or sprayed daily for 3 days with chemical inducers (SA and MeJA). Plants were analysed at 0, 24, 48, 72 and 96 h after inoculation with Fusarium oxysporum f. sp. lycopersici. Infection of tomato plants by pathogen led to strong reduction in the dry weight of roots and shoots with the enhanced concentration of H 2 O 2 and varying degree of lipid peroxidation. Concurrently, exogenous SA, when applied with pathogen greatly enhanced H 2 O 2 content as well as activities of antioxidant enzymes except catalase (CAT) and ascorbate peroxidase (APx). The pathogen challenged plants pretreated with T. harzianum and MeJA together exhibited less lipid peroxidation and as well as the elevated level of ascorbic acid and enhanced activities of antioxidant enzymes. All applied treatments protected tomato seedlings against Fusarium wilt disease but the percentage of protection was found higher in plants pretreated with the combination of T. harzianum and chemical inducers.

Silicon Regulates Antioxidant Activities of Crop Plants under Abiotic-Induced Oxidative Stress: A Review.

PubMed

Kim, Yoon-Ha; Khan, Abdul L; Waqas, Muhammad; Lee, In-Jung

2017-01-01

Silicon (Si) is the second most abundant element in soil, where its availability to plants can exhilarate to 10% of total dry weight of the plant. Si accumulation/transport occurs in the upward direction, and has been identified in several crop plants. Si application has been known to ameliorate plant growth and development during normal and stressful conditions over past two-decades. During abiotic (salinity, drought, thermal, and heavy metal etc) stress, one of the immediate responses by plant is the generation of reactive oxygen species (ROS), such as singlet oxygen ( 1 O 2 ), superoxide ([Formula: see text]), hydrogen peroxide (H 2 O 2 ), and hydroxyl radicals (OH), which cause severe damage to the cell structure, organelles, and functions. To alleviate and repair this damage, plants have developed a complex antioxidant system to maintain homeostasis through non-enzymatic (carotenoids, tocopherols, ascorbate, and glutathione) and enzymatic antioxidants [superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase (APX)]. To this end, the exogenous application of Si has been found to induce stress tolerance by regulating the generation of ROS, reducing electrolytic leakage, and malondialdehyde (MDA) contents, and immobilizing and reducing the uptake of toxic ions like Na, under stressful conditions. However, the interaction of Si and plant antioxidant enzyme system remains poorly understood, and further in-depth analyses at the transcriptomic level are needed to understand the mechanisms responsible for the Si-mediated regulation of stress responses.

Studies on chemical constituents and bioactivity of Rosa micrantha: an alternative antioxidants source for food, pharmaceutical, or cosmetic applications.

PubMed

Guimarães, Rafaela; Barros, Lillian; Carvalho, Ana Maria; Ferreira, Isabel C F R

2010-05-26

Rose species have long been used for food and medicinal purposes. Rosa micrantha is one of the rose species that grow feral in the northeastern Portuguese region so-called Nordeste Transmontano. For the first time, chemical composition and bioactivity of their petals, fertilized flowers, unripe, ripening, and overripe hips were evaluated in order to valorize them as sources of important phytochemicals. Chemical characterization included determination of proteins, fats, ash, and carbohydrates, particularly sugars, by HPLC-RI, fatty acids by GC-FID, tocopherols by HPLC-fluorescence, and phenolics, flavonoids, carotenoids, and ascorbic acid by spectrophotometric techniques. Bioactivity was evaluated through screening of antioxidant properties: radical scavenging effects, reducing power, and inhibition of lipid peroxidation. Ripening and overripe hips showed high nutritional value including proteins, carbohydrates, omega-3 and omega-6 fatty acids, energy, sugars, particularly the reducing sugars fructose and glucose, and ascorbic acid (>693 mg/100 g). Fertilized flowers and petals revealed the highest antioxidant activity (EC(50) > 152 microg/mL) and phenolics, flavonoids, and tocopherols contents (>35 mg/100 g). Furthermore, petals, ripening, and overripe hips are important sources of carotenoid pigments (>64 mg/100 g). Because of the diversity and abundance of antioxidants found in this species, some food, cosmetic, and pharmaceutical applications could be explored.

Effects of water-soluble natural antioxidants on photosensitized oxidation of conjugated linoleic acid in an oil-in-water emulsion system.

PubMed

Liu, T-T; Yang, T-S

2008-05-01

The effect of photosensitized oxidation of conjugated linoleic acid in an oil-in-water (o/w) emulsion system was studied. Water-soluble natural antioxidants, including apple polyphenols from apple extract, green tea extract, 4-hydroxy-2(or 5)-ethyl-5(or2)-methyl-3(2H)-furanone(HEMF), 4-hydroxy-2,5-dimethyl-3(2H)-furanone (HDMF), and ascorbic acid, were tested for antioxidant activity in this system. The green tea extract showed the highest antioxidant activity followed by ascorbic acid. Apple polyphenols did not give significant antioxidant activity. HEMF and HDMF exhibited a prooxidant effect. The antioxidant activity of tea catechins was also investigated. Of them, EGCG and ECG exhibited antioxidant activity at 50 ppm, but the antioxidant activity between them was not significantly different (P < 0.05). Comparatively, EC, EGC, and GCG showed no significant antioxidative effect at 50 ppm. When the concentration increased to 100 ppm, the antioxidant activity of ECG and EGCG significantly increased compared with that at 50 ppm, and EGCG had higher antioxidant activity than ECG. GCG also showed significant antioxidant activity at 100 ppm. EGCG exhibited the highest antioxidant activity among the tea catechins in the emulsion system at 100 ppm.

Modulation of oxidative stress by beta-carotene in chicken embryo fibroblasts.

PubMed

Lawlor, S M; O'Brien, N M

1995-06-01

The ability of beta-carotene to protect against oxidative stress in vitro was assessed. Primary cultures of chicken embryo fibroblasts (CEF) were oxidatively stressed by exposure to paraquat (PQ). Activities of the antioxidant enzymes superoxide dismutase (SOD; EC 1.15.1.1), catalase (CAT; EC 1.11.1.6) and glutathione peroxidase (GSH-Px; EC 1.11.19) were measured as indices of oxidative stress. CEF incubated with 0.25 mM-PQ for 18 h exhibited increased SOD and CAT activities and decreased GSH-Px activity compared with the control (P < 0.001). Incorporation of added beta-carotene (0.1 microM) into 0.25 mM-PQ-treated CEF returned SOD activity to that seen in non-PQ-treated cells. beta-Carotene (0.1 microM) reduced the CAT activity from that seen in PQ-treated cells and returned the GSH-Px activity to its control value thus protecting the cells against PQ-induced oxidative stress. However, at higher concentrations of beta-carotene (10 microM), SOD and CAT activities increased significantly (P < 0.001) relative to non-PQ-treated cells and GSH-Px activity decreased relative to its control value. Similar trends were observed when CEF grown in beta-carotene-enriched media (0.1-10 microM) were oxidatively stressed by exposure to 0.25 mM-PQ for 18 h.

Prevention of enzymatic browning of Chinese yam (Dioscorea spp.) using electrolyzed oxidizing water.

PubMed

Jia, Guo-Liang; Shi, Jing-Ying; Song, Zhan-Hua; Li, Fa-De

2015-04-01

In this study, the effects of electrolyzed oxidizing water (EOW) on the prevention of enzymatic browning of fresh-cut "Jiu Jinhuang" Chinese yam were investigated. The yams were immersed in the inhibitors for 25 min at 20 °C. Compared with the tap water (TW) treatment, the chromatic attributes were significantly different after 72 h of storage (P < 0.05). The activities of polyphenol oxidase (PPO, EC 1.10.3.1), peroxidase (POD, EC 1.11.1.7), and L -phenylalanine ammonia lyase (PAL, EC 4.3.1.5) were inhibited when measured at 24 h. The contents of phenolic acids, including gallic and chlorogenic acid, in the group treated with the slightly acidic electrolyzed water (SAEW) were higher than those treated with TW and neutral electrolyzed water (NEW). The group treated with NEW had the highest total phenol content (P < 0.05, at 24 h), while the group treated with SAEW had the highest flavonoid content (P < 0.05) during storage. Without being treated with inhibitors, the Km and Vmax values of yam PPO were 0.0044 mol/L and 0.02627 U/min, respectively, and the Ki of samples treated with SAEW and citric acid (CA) were 15.6607 and 2.3969 μmol/L, respectively. These results indicate that EOW is beneficial as a browning inhibitor. © 2015 Institute of Food Technologists®

Impact of ambient and supplemental ultraviolet-B stress on kidney bean plants: an insight into oxidative stress management.

PubMed

Singh, Suruchi; Sarkar, Abhijit; Agrawal, S B; Agrawal, Madhoolika

2014-11-01

In the present study, the response of kidney bean (Phaseolus vulgaris L. cv. Pusa Komal) plants was evaluated under three different levels of ultraviolet-B (UV-B), i.e., excluded UV-B (eUV-B), ambient UV-B (aUV-B; 5.8 kJ m(-2) day(-1)), and supplemental UV-B (sUV-B; 280-315 nm; ambient + 7.2 kJ m(-2) day(-1)), under near-natural conditions. eUV-B treatment clearly demonstrated that both aUV-B and sUV-B are capable of causing significant changes in the plant's growth, metabolism, economic yield, genome template stability, total protein, and antioxidative enzyme profiles. The experimental findings showed maximum plant height at eUV-B, but biomass accumulation was minimum. Significant reductions in quantum yield (Fv/Fm) were observed under both aUV-B and sUV-B, as compared to eUV-B. UV-B-absorbing flavonoids increased under higher UV-B exposures with consequent increments in phenylalanine ammonia lyase (PAL) activities. The final yield was significantly higher in plants grown under eUV-B, compared to those under aUV-B and sUV-B. Total protein profile through sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and analysis of isoenzymes, like superoxide dismutase (SOD), peroxidase (POX), catalase (CAT), ascorbate peroxidase (APX), guaiacol peroxidase (GPX), and glutathione reductase (GR), through native PAGE revealed major changes in the leaf proteome under aUV-B and sUV-B, depicting induction of some major stress-related proteins. The random amplified polymorphic DNA (RAPD) profile of genomic DNA also indicated a significant reduction of genome template stability under UV-B exposure. Thus, it can be inferred that more energy is diverted for inducing protection mechanisms rather than utilizing it for growth under high UV-B level.

Glutathione Transferase from Trichoderma virens Enhances Cadmium Tolerance without Enhancing Its Accumulation in Transgenic Nicotiana tabacum

PubMed Central

Dixit, Prachy; Mukherjee, Prasun K.; Ramachandran, V.; Eapen, Susan

2011-01-01

Background Cadmium (Cd) is a major heavy metal pollutant which is highly toxic to plants and animals. Vast agricultural areas worldwide are contaminated with Cd. Plants take up Cd and through the food chain it reaches humans and causes toxicity. It is ideal to develop plants tolerant to Cd, without enhanced accumulation in the edible parts for human consumption. Glutathione transferases (GST) are a family of multifunctional enzymes known to have important roles in combating oxidative stresses induced by various heavy metals including Cd. Some GSTs are also known to function as glutathione peroxidases. Overexpression/heterologous expression of GSTs is expected to result in plants tolerant to heavy metals such as Cd. Results Here, we report cloning of a glutathione transferase gene from Trichoderma virens, a biocontrol fungus and introducing it into Nicotiana tabacum plants by Agrobacterium-mediated gene transfer. Transgenic nature of the plants was confirmed by Southern blot hybridization and expression by reverse transcription PCR. Transgene (TvGST) showed single gene Mendelian inheritance. When transgenic plants expressing TvGST gene were exposed to different concentrations of Cd, they were found to be more tolerant compared to wild type plants, with transgenic plants showing lower levels of lipid peroxidation. Levels of different antioxidant enzymes such as glutathione transferase, superoxide dismutase, ascorbate peroxidase, guiacol peroxidase and catalase showed enhanced levels in transgenic plants expressing TvGST compared to control plants, when exposed to Cd. Cadmium accumulation in the plant biomass in transgenic plants were similar or lower than wild-type plants. Conclusion The results of the present study suggest that transgenic tobacco plants expressing a Trichoderma virens GST are more tolerant to Cd, without enhancing its accumulation in the plant biomass. It should be possible to extend the present results to crop plants for developing Cd tolerance and in limiting Cd availability in the food chain. PMID:21283689

Physiological and Proteomic Responses of Contrasting Alfalfa (Medicago sativa L.) Varieties to PEG-Induced Osmotic Stress.

PubMed

Zhang, Cuimei; Shi, Shangli

2018-01-01

Drought severely limits global plant distribution and agricultural production. Elucidating the physiological and molecular mechanisms governing alfalfa stress responses will contribute to the improvement of drought tolerance in leguminous crops. In this study, the physiological and proteomic responses of two alfalfa ( Medicago sativa L.) varieties contrasting in drought tolerance, Longzhong (drought-tolerant) and Gannong No. 3 (drought-sensitive), were comparatively assayed when seedlings were exposed to -1.2 MPa polyethylene glycol (PEG-6000) treatments for 15 days. The results showed that the levels of proline, malondialdehyde (MDA), hydrogen peroxide (H 2 O 2 ), hydroxyl free radical (OH • ) and superoxide anion free radical (O 2 •- ) in both varieties were significantly increased, while the root activity, the superoxide dismutase (SOD) and glutathione reductase (GR) activities, and the ratios of reduced/oxidized ascorbate (AsA/DHA) and reduced/oxidized glutathione (GSH/GSSG) were significantly decreased. The soluble protein and soluble sugar contents, the total antioxidant capability (T-AOC) and the activities of peroxidase (POD), catalase (CAT), and ascorbate peroxidase (APX) first increased and then decreased with the increase in treatment days. Under osmotic stress, Longzhong exhibited lower levels of MDA, H 2 O 2 , OH • and O 2 •- but higher levels of SOD, CAT, APX, T-AOC and ratios of AsA/DHA and GSH/GSSG compared with Gannong No.3. Using isobaric tags for relative and absolute quantification (iTRAQ), 142 differentially accumulated proteins (DAPs) were identified from two alfalfa varieties, including 52 proteins (34 up-regulated and 18 down-regulated) in Longzhong, 71 proteins (28 up-regulated and 43 down-regulated) in Gannong No. 3, and 19 proteins (13 up-regulated and 6 down-regulated) shared by both varieties. Most of these DAPs were involved in stress and defense, protein metabolism, transmembrane transport, signal transduction, as well as cell wall and cytoskeleton metabolism. In conclusion, the stronger drought-tolerance of Longzhong was attributed to its higher osmotic adjustment capacity, greater ability to orchestrate its enzymatic and non-enzymatic antioxidant systems and thus avoid great oxidative damage in comparison to Gannong No. 3. Moreover, the involvement of other pathways, including carbohydrate metabolism, ROS detoxification, secondary metabolism, protein processing, ion and water transport, signal transduction, and cell wall adjustment, are important mechanisms for conferring drought tolerance in alfalfa.

Physiological and Proteomic Responses of Contrasting Alfalfa (Medicago sativa L.) Varieties to PEG-Induced Osmotic Stress

PubMed Central

Zhang, Cuimei; Shi, Shangli

2018-01-01

Drought severely limits global plant distribution and agricultural production. Elucidating the physiological and molecular mechanisms governing alfalfa stress responses will contribute to the improvement of drought tolerance in leguminous crops. In this study, the physiological and proteomic responses of two alfalfa (Medicago sativa L.) varieties contrasting in drought tolerance, Longzhong (drought-tolerant) and Gannong No. 3 (drought-sensitive), were comparatively assayed when seedlings were exposed to -1.2 MPa polyethylene glycol (PEG-6000) treatments for 15 days. The results showed that the levels of proline, malondialdehyde (MDA), hydrogen peroxide (H2O2), hydroxyl free radical (OH•) and superoxide anion free radical (O2•-) in both varieties were significantly increased, while the root activity, the superoxide dismutase (SOD) and glutathione reductase (GR) activities, and the ratios of reduced/oxidized ascorbate (AsA/DHA) and reduced/oxidized glutathione (GSH/GSSG) were significantly decreased. The soluble protein and soluble sugar contents, the total antioxidant capability (T-AOC) and the activities of peroxidase (POD), catalase (CAT), and ascorbate peroxidase (APX) first increased and then decreased with the increase in treatment days. Under osmotic stress, Longzhong exhibited lower levels of MDA, H2O2, OH• and O2•- but higher levels of SOD, CAT, APX, T-AOC and ratios of AsA/DHA and GSH/GSSG compared with Gannong No.3. Using isobaric tags for relative and absolute quantification (iTRAQ), 142 differentially accumulated proteins (DAPs) were identified from two alfalfa varieties, including 52 proteins (34 up-regulated and 18 down-regulated) in Longzhong, 71 proteins (28 up-regulated and 43 down-regulated) in Gannong No. 3, and 19 proteins (13 up-regulated and 6 down-regulated) shared by both varieties. Most of these DAPs were involved in stress and defense, protein metabolism, transmembrane transport, signal transduction, as well as cell wall and cytoskeleton metabolism. In conclusion, the stronger drought-tolerance of Longzhong was attributed to its higher osmotic adjustment capacity, greater ability to orchestrate its enzymatic and non-enzymatic antioxidant systems and thus avoid great oxidative damage in comparison to Gannong No. 3. Moreover, the involvement of other pathways, including carbohydrate metabolism, ROS detoxification, secondary metabolism, protein processing, ion and water transport, signal transduction, and cell wall adjustment, are important mechanisms for conferring drought tolerance in alfalfa. PMID:29541085

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

PubMed

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 of V. vitis-idaea were accompanied by a decreased activity of guaiacol peroxidase. In both species increased Mn accumulation caused a decrease in antioxidant response.

Climate Change and the Impact of Greenhouse Gasses: CO2 and NO, Friends and Foes of Plant Oxidative Stress.

PubMed

Cassia, Raúl; Nocioni, Macarena; Correa-Aragunde, Natalia; Lamattina, Lorenzo

2018-01-01

Here, we review information on how plants face redox imbalance caused by climate change, and focus on the role of nitric oxide (NO) in this response. Life on Earth is possible thanks to greenhouse effect. Without it, temperature on Earth's surface would be around -19°C, instead of the current average of 14°C. Greenhouse effect is produced by greenhouse gasses (GHG) like water vapor, carbon dioxide (CO 2 ), methane (CH 4 ), nitrous oxides (N x O) and ozone (O 3 ). GHG have natural and anthropogenic origin. However, increasing GHG provokes extreme climate changes such as floods, droughts and heat, which induce reactive oxygen species (ROS) and oxidative stress in plants. The main sources of ROS in stress conditions are: augmented photorespiration, NADPH oxidase (NOX) activity, β-oxidation of fatty acids and disorders in the electron transport chains of mitochondria and chloroplasts. Plants have developed an antioxidant machinery that includes the activity of ROS detoxifying enzymes [e.g., superoxide dismutase (SOD), ascorbate peroxidase (APX), catalase (CAT), glutathione peroxidase (GPX), and peroxiredoxin (PRX)], as well as antioxidant molecules such as ascorbic acid (ASC) and glutathione (GSH) that are present in almost all subcellular compartments. CO 2 and NO help to maintain the redox equilibrium. Higher CO 2 concentrations increase the photosynthesis through the CO 2 -unsaturated Rubisco activity. But Rubisco photorespiration and NOX activities could also augment ROS production. NO regulate the ROS concentration preserving balance among ROS, GSH, GSNO, and ASC. When ROS are in huge concentration, NO induces transcription and activity of SOD, APX, and CAT. However, when ROS are necessary (e.g., for pathogen resistance), NO may inhibit APX, CAT, and NOX activity by the S-nitrosylation of cysteine residues, favoring cell death. NO also regulates GSH concentration in several ways. NO may react with GSH to form GSNO, the NO cell reservoir and main source of S-nitrosylation. GSNO could be decomposed by the GSNO reductase (GSNOR) to GSSG which, in turn, is reduced to GSH by glutathione reductase (GR). GSNOR may be also inhibited by S-nitrosylation and GR activated by NO. In conclusion, NO plays a central role in the tolerance of plants to climate change.

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

PubMed

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 by influencing gene expression of antioxidant proteins, but excessive dietary AA (829.8 and 4967.5 mg kg(-1)) induced oxidative stress in Pacific abalone H. discus hannai. Copyright © 2014 Elsevier Ltd. All rights reserved.

Climate Change and the Impact of Greenhouse Gasses: CO2 and NO, Friends and Foes of Plant Oxidative Stress

PubMed Central

Cassia, Raúl; Nocioni, Macarena; Correa-Aragunde, Natalia; Lamattina, Lorenzo

2018-01-01

Here, we review information on how plants face redox imbalance caused by climate change, and focus on the role of nitric oxide (NO) in this response. Life on Earth is possible thanks to greenhouse effect. Without it, temperature on Earth’s surface would be around -19°C, instead of the current average of 14°C. Greenhouse effect is produced by greenhouse gasses (GHG) like water vapor, carbon dioxide (CO2), methane (CH4), nitrous oxides (NxO) and ozone (O3). GHG have natural and anthropogenic origin. However, increasing GHG provokes extreme climate changes such as floods, droughts and heat, which induce reactive oxygen species (ROS) and oxidative stress in plants. The main sources of ROS in stress conditions are: augmented photorespiration, NADPH oxidase (NOX) activity, β-oxidation of fatty acids and disorders in the electron transport chains of mitochondria and chloroplasts. Plants have developed an antioxidant machinery that includes the activity of ROS detoxifying enzymes [e.g., superoxide dismutase (SOD), ascorbate peroxidase (APX), catalase (CAT), glutathione peroxidase (GPX), and peroxiredoxin (PRX)], as well as antioxidant molecules such as ascorbic acid (ASC) and glutathione (GSH) that are present in almost all subcellular compartments. CO2 and NO help to maintain the redox equilibrium. Higher CO2 concentrations increase the photosynthesis through the CO2-unsaturated Rubisco activity. But Rubisco photorespiration and NOX activities could also augment ROS production. NO regulate the ROS concentration preserving balance among ROS, GSH, GSNO, and ASC. When ROS are in huge concentration, NO induces transcription and activity of SOD, APX, and CAT. However, when ROS are necessary (e.g., for pathogen resistance), NO may inhibit APX, CAT, and NOX activity by the S-nitrosylation of cysteine residues, favoring cell death. NO also regulates GSH concentration in several ways. NO may react with GSH to form GSNO, the NO cell reservoir and main source of S-nitrosylation. GSNO could be decomposed by the GSNO reductase (GSNOR) to GSSG which, in turn, is reduced to GSH by glutathione reductase (GR). GSNOR may be also inhibited by S-nitrosylation and GR activated by NO. In conclusion, NO plays a central role in the tolerance of plants to climate change. PMID:29545820

Lemna minor exposed to fluoranthene: growth, biochemical, physiological and histochemical changes.

PubMed

Zezulka, Stěpán; Kummerová, Marie; Babula, Petr; Váňová, Lucie

2013-09-15

Polycyclic aromatic hydrocarbons (PAHs) represent one of the major groups of organic contaminants in the aquatic environment. Duckweed (Lemna minor L.) is a common aquatic plant widely used in phytotoxicity tests for xenobiotic substances. The goal of this study was to assess the growth and the physiological, biochemical and histochemical changes in duckweed exposed for 4 and 10 days to fluoranthene (FLT, 0.1 and 1 mgL(-1)). Nonsignificant changes in number of plants, biomass production, leaf area size, content of chlorophylls a and b and carotenoids and parameters of chlorophyll fluorescence recorded after 4 and 10 days of exposure to FLT were in contrast with considerable changes at biochemical and histochemical levels. Higher occurrence of reactive oxygen species (ROS) caused by an exposure to FLT after 10 days as compared to control (hydrogen peroxide elevated by 13% in the 0.1 mgL(-1) and by 41% in the 1 mgL(-1) FLT; superoxide anion radical by 52% and 115% respectively) reflected in an increase in the activities of antioxidant enzymes (superoxide dismutase by 3% in both treatments, catalase by 9% and 1% respectively, ascorbate peroxidase by 21% and 5% respectively, guaiacol peroxidase by 12% in the 0.1 mgL(-1) FLT). Even the content of antioxidant compounds like ascorbate (by 20% in the 1 mgL(-1) FLT) or total thiols (reduced forms by 15% in the 0.1 mgL(-1) and 8% in the 1 mgL(-1) FLT, oxidized forms by 36% in the 0.1 mgL(-1) FLT) increased. Increased amount of ROS was followed by an increase in malondialdehyde content (by 33% in the 0.1 mgL(-1) and 79% in the 1 mgL(-1) FLT). Whereas in plants treated by the 0.1 mgL(-1) FLT the contents of total proteins and phenols increased by 15% and 25%, respectively, the 1 mgL(-1) FLT caused decrease of their contents by 32% and 7%. Microscopic observations of duckweed roots also confirmed the presence of ROS and related histochemical changes at the cellular and tissue levels. The assessment of phytotoxicity of organic pollutant in duckweed based only on the evaluation of growth parameters could not fully cover the irreversible changes already running at the level of biochemical processes. Copyright © 2013 Elsevier B.V. All rights reserved.

Interdependence of plant water status with photosynthetic performance and root defense responses in Vigna radiata (L.) Wilczek under progressive drought stress and recovery.

PubMed

Sengupta, Debashree; Guha, Anirban; Reddy, Attipalli Ramachandra

2013-10-05

The present study investigates the interdependence of plant water status with foliar and root responses in Vigna radiata L.Wilczek under progressive drought. Vegetatively-mature V. radiata plants were subjected to water withdrawal for 3 and 6days (D3 and D6, respectively) and then re-watered subsequently for 6days (6R) for stress-recovery. Changes in plant water status were expressed in terms of leaf and root moisture contents (LMC and RMC, respectively) and leaf relative water content (LRWC). Progressive drought caused apparent decrease in LRWC, LMC and RMC depicting significant level of dehydration of leaf and root tissues. Stomatal limitation alone could not account for the observed decrease in net CO2 assimilation rates (Pn) due to comparatively less decrease in sub-stomatal CO2 (Ci) concentrations with respect to other gas exchange parameters indicating possible involvement of non-stomatal limitations. Analysis of polyphasic chl a fluorescence kinetics during progressive drought showed decreased energy connectivity among PSII units as defined by a positive L-band with highest amplitude during D6. Efficiency of electron flux from OEC towards PSII acceptor side was not significantly affected during drought conditions as evidenced by the absence of a positive K-band. Increasing root-level water-limitation enforced a gradual oxidative stress through H2O2 accumulation and membrane lipid peroxidation in V. radiata roots exhibiting drastic enhancement of proline content and a significant but gradual increase in ascorbic acid content as well as guaiacol peroxidase activity under progressive drought. Expression analysis of Δ(1) pyrroline-5-carboxylate synthetase (P5CS) through real time PCR and enzyme activity studies showed a strong positive correlation between VrP5CS gene expression, enzyme activity and proline accumulation in the roots of V. radiata under progressive drought and recovery. Drought-induced changes in root moisture content (RMC) showed positive linear correlations with leaf water content, stomatal conductance as well as transpirational water loss dynamics and a significant negative correlation with the corresponding drought-induced expression patterns of ascorbate, guaiacol peroxidase and proline in roots of V. radiata. The study provides new insights into the plant water status-dependent interrelationship between photosynthetic performance and major root defense responses of V. radiata under progressive drought conditions. Copyright © 2013 Elsevier B.V. All rights reserved.

Health-Promoting Effects of Thymus herba-barona, Thymus pseudolanuginosus, and Thymus caespititius Decoctions

PubMed Central

Afonso, Andrea F.; Pereira, Olívia R.; Neto, Rodrigo T.

2017-01-01

Thymus herba-barona, Thymus pseudolanuginosus, and Thymus caespititius decoctions were screened for their phenolic constituents, along with their potential antioxidant, anti-inflammatory, and antibacterial activities. The total phenolic compounds in the extracts of the three plants ranged from 236.0 ± 26.6 mgGAE/g (T. caespititus) to 293.0 ± 30.5 mgGAE/g of extract (T. pseudolanuginosus), being particularly rich in caffeic acid derivatives, namely rosmarinic acid and its structural isomers, as well as flavones, such as luteolin-O-glucuronide. The T. pseudolanuginosus extract presented the best DPPH radical scavenging ability (EC50 = 10.9 ± 0.7 µg/mL), a high reducing power (EC50 = 32.2 ± 8.2 µg/mL), and effectively inhibited the oxidation of β-carotene (EC50 = 2.4 ± 0.2 µg/mL). The extracts also showed NO● scavenging activity close to that of ascorbic acid, and thus might be useful as anti-inflammatory agents. In addition, they exhibited antibacterial activity against gram-negative and gram-positive bacteria. Staphylococcus aureus strains were the most sensitive bacteria to thyme extracts, with minimum inhibitory concentration and minimum bactericidal concentration values in the range of 0.6–3.5 mg/mL. Overall, this work is an important contribution for the phytochemical characterization and the potential antioxidant, anti-inflammatory, and antimicrobial activities of these three Thymus species, which have been poorly explored. PMID:28858228

Optimization of Supercritical Fluid Extraction of Total Alkaloids, Peimisine, Peimine and Peiminine from the Bulb of Fritillaria thunbergii Miq, and Evaluation of Antioxidant Activities of the Extracts

PubMed Central

Ruan, Xiao; Yang, Li; Cui, Wen-Xia; Zhang, Men-Xing; Li, Zhao-Hui; Liu, Ben; Wang, Qiang

2016-01-01

Supercritical fluid extraction (SFE) was used to extract total alkaloids, peimisine, peimine and peiminine from the bulb of Fritillaria thunbergii Miq. The antioxidant capacity of the extracts was evaluated by DPPH radical scavenging activity (DPPH-RSA), ABTS radical scavenging activity (ABTS-RSA) and ferric reducing capacity (FRAP) assay. A central composite design (CCD) with four variables and five levels was employed for optimization of process parameters, and response surface plots were constructed in accordance with a second order polynomial model. Under optimal conditions of 3.0 h, 60.4 °C, 26.5 MPa and 89.3% ethanol, the highest yields were predicted to be 3.8 mg/g for total alkaloids, 0.5 mg/g for peimisine, 1.3 mg/g for peimine and 1.3 mg/g for peiminine, and the antioxidant capacity of extracts displayed EC50, DPPH value of 5.5 mg/mL, EC50, ABTS value of 0.3 mg/mL and FRAP value of 118.2 mg ascorbic acid equivalent (AAE)/100 g. PMID:28773648

Gut-based antioxidant enzymes in a polyphagous and a graminivorous grasshopper.

PubMed

Barbehenn, Raymond V

2002-07-01

Graminivorous species of grasshoppers develop lethal lesions in their midgut epithelia when they ingest tannic acid, whereas polyphagous grasshoppers are unaffected by ingested tannins. This study tests the hypothesis that polyphagous species are defended by higher activities of antioxidant enzymes (constitutive or inducible) in their guts than are graminivorous species. Comparisons were made between four antioxidant enzymes: superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APOX), and glutathione transferase peroxidase (GSTPX). Enzyme activities were measured in the gut lumens and midgut tissues of Melanoplus sanguinipes (polyphagous) and Aulocara ellioti (graminivorous). The results of this study do not support the hypothesis that M. sanguinipes is better defended by antioxidant enzymes than is A. ellioti, nor are these enzymes more inducible in M. sanguinipes than in A. ellioti when insects consume food containing 15% dry weight tannic acid. Instead, tannic acid consumption reduced SOD, APOX, and GSTPX activities in both species. This study reports the first evidence that SOD is secreted into the midgut lumen in insects, with activities two- to fourfold higher than those found in midgut tissues. The spatial distribution of GSTPX and APOX activities observed in both species suggests that ingested plant antioxidant enzymes may function as acquired defenses in grasshoppers. In addition, the results of this study permit the first comparison between the antioxidant enzyme defenses of Orthoptera and Lepidoptera. Most notably, grasshoppers have higher SOD activities than caterpillars, but completely lack APOX in their midgut tissues.

EDTA ameliorates phytoextraction of lead and plant growth by reducing morphological and biochemical injuries in Brassica napus L. under lead stress.

PubMed

Kanwal, Urooj; Ali, Shafaqat; Shakoor, Muhammad Bilal; Farid, Mujahid; Hussain, Sabir; Yasmeen, Tahira; Adrees, Muhammad; Bharwana, Saima Aslam; Abbas, Farhat

2014-01-01

Brassica species are very effective in remediation of heavy metal contaminated sites. Lead (Pb) as a toxic pollutant causes number of morphological and biochemical variations in the plants. Synthetic chelator such as ethylenediaminetetraacetic acid (EDTA) improves the capability of plants to uptake heavy metals from polluted soil. In this regard, the role of EDTA in phytoextraction of lead, the seedlings of Brassica napus L. were grown hydroponically. Lead levels (50 and 100 μM) were supplied alone or together with 2.5 mM EDTA in the nutrient culture. After 7 weeks of stress, plants indicated that toxicity of Pb caused negative effects on plants and significantly reduced growth, biomass, chlorophyll content, gas exchange characteristics, and antioxidant enzymes activities such as superoxide dismutase (SOD), guaiacol peroxidase (POD), ascorbate peroxidase (APX), and catalase (CAT). Exposure to Pb induced the malondialdehyde (MDA), and hydrogen peroxide (H2O2) generation in both shoots and roots. The addition of EDTA alone or in combination with Pb significantly improved the plant growth, biomass, gas exchange characteristics, chlorophyll content, and antioxidant enzymes activities. EDTA also caused substantial improvement in Pb accumulation in Brassica plants. It can be deduced that application of EDTA significantly lessened the adverse effects of lead toxicity. Additionally, B. napus L. exhibited greater degree of tolerance against Pb toxicity and it also accumulated significant concentration of Pb from media.

Calcium protects Trifolium repens L. seedlings against cadmium stress.

PubMed

Wang, Chang Quan; Song, Heng

2009-09-01

The effect of calcium (Ca(2+)) on Trifolium repens L. seedlings subjected to cadmium (Cd(2+)) stress was studied by investigating plant growth and changes in activity of antioxidative enzymes. Physiological analysis was carried out on seedlings cultured for 2 weeks on half-strength Hoagland medium with Cd(2+) concentrations of 0, 400 and 600 microM, and on corresponding medium supplied with CaCl(2) (5 mM). Exposure to increasing Cd(2+) reduced the fresh weight of the upper part (stems + leaves) of the seedlings more strongly than that of the root system. In both parts of T. repens seedlings H(2)O(2) level and lipid peroxidation increased. In the upper part, Cd(2+) exposure led to a significant decrease in the activity of superoxide dismutase, catalase and glutathione peroxidase and an increase in ascorbate peroxidase activity. In contrast, the roots showed an increase in the activity of antioxidative enzymes under Cd(2+) stress. Ca(2+) addition to medium reduced the Cd(2+) accumulation, and considerably reversed the Cd(2+)-induced decrease in fresh mass as well as the changes in lipid peroxidation in the both parts of T. repens seedlings. Ca(2+) application diminished the Cd(2+) effect on the activity of antioxidative enzymes in the upper part, even though it did not significantly affect these enzymes in the roots. So the possible mechanisms for the action of Ca(2+) in Cd(2+) stress were considered to reduce Cd(2+) accumulation, alleviate lipid peroxidation and promote activity of antioxidative enzymes.

Deficiency and toxicity of boron: Alterations in growth, oxidative damage and uptake by citrange orange plants.

PubMed

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.

Green Synthesized Zinc Oxide (ZnO) Nanoparticles Induce Oxidative Stress and DNA Damage in Lathyrus sativus L. Root Bioassay System

PubMed Central

Panda, Kamal K.; Golari, Dambaru; Venugopal, A.; Achary, V. Mohan M.; Phaomei, Ganngam; Parinandi, Narasimham L.; Sahu, Hrushi K.; Panda, Brahma B.

2017-01-01

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 Zn2+ 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 Zn2+ alone. PMID:28524089

Sulfur Dioxide Enhances Endogenous Hydrogen Sulfide Accumulation and Alleviates Oxidative Stress Induced by Aluminum Stress in Germinating Wheat Seeds

PubMed Central

Zhu, Dong-Bo; Hu, Kang-Di; Guo, Xi-Kai; Liu, Yong; Hu, Lan-Ying; Li, Yan-Hong; Wang, Song-Hua; Zhang, Hua

2015-01-01

Aluminum ions are especially toxic to plants in acidic soils. Here we present evidences that SO2 protects germinating wheat grains against aluminum stress. SO2 donor (NaHSO3/Na2SO3) pretreatment at 1.2 mM reduced the accumulation of superoxide anion, hydrogen peroxide, and malondialdehyde, enhanced the activities of guaiacol peroxidase, catalase, and ascorbate peroxidase, and decreased the activity of lipoxygenase in germinating wheat grains exposed to Al stress. We also observed higher accumulation of hydrogen sulfide (H2S) in SO2-pretreated grain, suggesting the tight relation between sulfite and sulfide. Wheat grains geminated in water for 36 h were pretreated with or without 1 mM SO2 donor for 12 h prior to exposure to Al stress for 48 h and the ameliorating effects of SO2 on wheat radicles were studied. SO2 donor pretreatment reduced the content of reactive oxygen species, protected membrane integrity, and reduced Al accumulation in wheat radicles. Gene expression analysis showed that SO2 donor pretreatment decreased the expression of Al-responsive genes TaWali1, TaWali2, TaWali3, TaWali5, TaWali6, and TaALMT1 in radicles exposed to Al stress. These results suggested that SO2 could increase endogenous H2S accumulation and the antioxidant capability and decrease endogenous Al content in wheat grains to alleviate Al stress. PMID:26078810

Effects of UV-B irradiation on isoforms of antioxidant enzymes and their activities in red alga Grateloupia filicina (Rhodophyta)

NASA Astrophysics Data System (ADS)

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.

Phosphate alleviation of glyphosate-induced toxicity in Hydrocharis dubia (Bl.) Backer.

PubMed

Zhong, Guidi; Wu, Zhonghua; Liu, Nian; Yin, Jun

2018-05-30

Glyphosate, as a broad-spectrum herbicide, is frequently detected in water, and phosphorus widely enters the water due to the extensive use of phosphorus-containing substances in agriculture, industries and daily life. Thus, aquatic ecosystems are exposed to both glyphosate and phosphorus, which may affect aquatic organisms. In the present research, we studied the physiological responses of the floating aquatic plant species H. dubia to different concentrations of glyphosate (0, 1, 5, 15 mg/L) with different levels of phosphate (0, 50, 100 mg/L) after 14 days (d) of treatment. We explored glyphosate toxicity in H. dubia and investigated whether phosphate addition mitigates glyphosate toxicity in this species, which will provide a theoretical basis for the ecotoxicological study of aquatic plants. The results show that glyphosate significantly reduced the chlorophyll content, leaf number and root length of H. dubia, while it significantly increased the malondialdehyde (MDA), hydrogen peroxide (H 2 O 2 ), shikimate, proline, and soluble protein content and enzyme activities (superoxide dismutase (SOD), catalase (CAT), guaiacol peroxidase (POD), ascorbate peroxidase (APX) and polyphenol oxidase (PPO)) in H. dubia. After phosphate supplement, the MDA, H 2 O 2 , proline, and soluble protein contents and enzyme activities in the plants treated with glyphosate decreased. These results indicate that the concentration of glyphosate investigated in our study can cause oxidative stress and affect the growth of H. dubia. Phosphate can alleviate glyphosate-induced oxidative stress in H. dubia. Copyright © 2018 Elsevier B.V. All rights reserved.

Effects of exposure to nano and bulk sized TiO2 and CuO in Lemna minor.

PubMed

Dolenc Koce, Jasna

2017-10-01

Nanoparticles of TiO 2 and CuO are among most commonly used nanoparticles, and elevated concentrations of them are expected to be found in all environments, including aquatic. A standard growth inhibition test ISO/CD 20079 was used to determine the toxicity of nano sized and larger micro sized (bulk) particles in the concentrations of 0.1, 1, 10, 100 and 1000 μM CuO and TiO 2 on common duckweed (Lemna minor L.). Both nano and bulk CuO particles caused changes in the structure and function of treated plants. The number of fronds and colonies decreased by as much as 78%, the length of roots and fronds decreased by 99% and 14%, respectively. Furthermore, photochemical efficiency was reduced by up to 35%, and the activities of antioxidative enzymes guaiacol peroxidase, ascorbate peroxidase and glutathione reductase increased by more than 240%. The altered physiological state of the CuO exposed plants was also reflected in the elevated occurrence of necrosis and bleaching in the duckweed colonies. Nano sized particles of CuO proved more phytotoxic than bulk particles, and the effects of both studied CuO sizes were concentration dependent. On the other hand, both bulk and nano sized particles of TiO 2 caused no severe phytotoxic effects, there was no concentration dependence and they could be considered as non-harmful to common duckweed. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Effect of azoxystrobin fungicide on the physiological and biochemical indices and ginsenoside contents of ginseng leaves.

PubMed

Liang, Shuang; Xu, Xuanwei; Lu, Zhongbin

2018-04-01

The impact of fungicide azoxystrobin, applied as foliar spray, on the physiological and biochemical indices and ginsenoside contents of ginseng was studied in ginseng ( Panax ginseng Mey. cv. "Ermaya") under natural environmental conditions. Different concentrations of 25% azoxystrobin SC (150 g a.i./ha and 225 g a.i./ha) on ginseng plants were sprayed three times, and the changes in physiological and biochemical indices and ginsenoside contents of ginseng leaves were tested. Physiological and biochemical indices were measured using a spectrophotometer (Shimadzu UV-2450). Every index was determined three times per replication. Extracts of ginsenosides were analyzed by HPLC (Shimadzu LC20-AB) utilizing a GL-Wondasil C 18 column. Chlorophyll and soluble protein contents were significantly ( p  = 0.05) increased compared with the control by the application of azoxystrobin. Additionally, activities of superoxide dismutase, catalase, ascorbate peroxidase, peroxidase, and ginsenoside contents in azoxystrobin-treated plants were improved, and malondialdehyde content and O 2 - contents were reduced effectively. Azoxystrobin treatments to ginseng plants at all growth stages suggested that the azoxystrobin-induced delay of senescence was due to an enhanced antioxidant enzyme activity protecting the plants from harmful active oxygen species. When the dose of azoxystrobin was 225 g a.i./ha, the effect was more significant. This work suggested that azoxystrobin played a role in delaying senescence by changing physiological and biochemical indices and improving ginsenoside contents in ginseng leaves.

Early response of wheat antioxidant system with special reference to Fusarium head blight stress.

PubMed

Spanic, Valentina; Viljevac Vuletic, Marija; Abicic, Ivan; Marcek, Tihana

2017-06-01

Fusarium head blight (FHB) is a destructive fungal disease of wheat (Triticum aestivum L.) that causes significant grain yield losses and end-use quality reduction associated with contamination by the mycotoxin deoxynivalenol (DON). Three winter wheat varieties ('Vulkan', 'Kraljica' and 'Golubica') were screened for FHB resistance using artificial inoculation technique under field conditions. The aim of this study was to examine a relationship between FHB resistance and the effectiveness of enzyme antioxidant system of wheat varieties under different sampling times (3, 15, 24, 48, 96, 120 and 336 hai). In the time-course experiments FHB-resistant variety 'Vulkan' showed rapid induction of ascorbate peroxidase (APX) and polyphenol oxidase (PPO) activity in the early stages after infection (3 hai) and it seems that in 'Vulkan' FHB-resistance is associated with antioxidative enzymes activity. Moderately FHB resistant variety 'Kraljica' showed the higher guaiacol peroxidase (POD) activity and higher H 2 O 2 content after 24 hai, increased malondialdehyde (MDA) content at the beginning of infection (3, 15 hai) while induction of catalase (CAT), APX and PPO was delayed. FHB-susceptible variety 'Golubica' involved antioxidant enzymes in defense response much later. Based on our results the activity of antioxidant enzymes (APX and PPO) was more pronounced in 'Vulkan' than in FHB-medium resistant variety 'Kraljica' and FHB-susceptible 'Golubica'. The differences in antioxidant response of wheat varieties under Fusarium infestation could be the result of genetic properties. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

The effect and fate of water-soluble carbon nanodots in maize (Zea mays L.).

PubMed

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.

Effects of water-saving superabsorbent polymer on antioxidant enzyme activities and lipid peroxidation in corn (Zea mays L.) under drought stress.

PubMed

Islam, M Robiul; Hu, Yuegao; Mao, Sishuai; Jia, Pengfei; Eneji, A Egrinya; Xue, Xuzhang

2011-03-30

Drought is the most important abiotic stress factor limiting corn (Zea mays L.) growth and productivity. Therefore efficient management of soil moisture and study of metabolic changes in response to drought are important for improved production of corn. The objective of the present study was to gain a better understanding of drought tolerance mechanisms and improve soil water management strategies using a water-saving superabsorbent polymer (SAP) at 30 kg ha(-1) under three irrigation levels (adequate, moderate and deficit) using a new type of hydraulic pressure-controlled auto-irrigator. The results showed that relative water content and leaf water potential were much higher in corn treated with SAP. Although application of SAP reduced biomass accumulation by 11.1% under adequate irrigation, it increased the biomass markedly by 39.0% under moderate irrigation and 98.7% under deficit irrigation. Plants treated with SAP under deficit irrigation showed a significant decrease in superoxide dismutase, catalase, peroxidase, ascorbate peroxidase and glutathione reductase activities in leaves compared with control plants. The results of this study suggest that drought stress causes the production of oxygen radicals, leading to increased lipid peroxidation and oxidative stress in plants, and the application of a superabsorbent polymer could conserve soil water, making it available to plants for quenching oxidative stress and increasing biomass accumulation, especially under severe water stress. Copyright © 2010 Society of Chemical Industry.

Effect of proline on biochemical and molecular mechanisms in lettuce (Lactuca sativa L.) exposed to UV-B radiation.

PubMed

Aksakal, Ozkan; Tabay, Dilruba; Esringu, Aslıhan; Icoglu Aksakal, Feyza; Esim, Nevzat

2017-02-15

The purpose of the present study was to evaluate the role of proline (Pro) in relieving UV-B radiation-induced oxidative stress in lettuce. Lettuce seedlings were exposed to 3.3 W m -2 UV-B radiation for 12 h after pre-treatment sprayed with 20 mM Pro. The data for malondialdehyde (MDA), hydrogen peroxide (H 2 O 2 ), endogenous Pro level, the activities of antioxidant enzymes [superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), and peroxidase (POD)], total phenolic concentration, antioxidant capacity, expression of phenylalanine ammonia lyase (PAL), γ-tocopherol methyltransferase (γ-TMT) and proline dehydrogenase (ProDH) genes, phytohormone levels such as abscisic acid (ABA), gibberellic acid (GA), indole acetic acid (IAA) and salicylic acid (SA), soluble sugars and organic acids were recorded. It was found that Pro alleviated the oxidative damage in the seedlings of lettuce as demonstrated by lower lipid peroxidation and H 2 O 2 content, increasing the endogenous Pro level, the activity of antioxidant enzymes, total phenolic concentration and the antioxidant capacity. Additionally, it was revealed that exogenous application of Pro enhanced the levels of GA, IAA, the concentrations of soluble sugars and organic acids and expressions of PAL, γ-TMT and ProDH genes as compared to the control. The results obtained in this study suggest that pre-treatment with exogenous Pro provides important contributions to the increase in the UV-B tolerance of lettuce by regulating the biochemical mechanisms of UV-B response.

An Enzyme Switch Employing Direct Electrochemical Communication between Horseradish Peroxidase and a Poly(aniline) Film.

PubMed

Bartlett, P N; Birkin, P R; Wang, J H; Palmisano, F; De Benedetto, G

1998-09-01

An enzyme switch, or microelectrochemical enzyme transistor, responsive to hydrogen peroxide was made by connecting two carbon band electrodes (∼10 μm wide, 4.5 mm long separated by a 20-μm gap) with an anodically grown film of poly(aniline). Horseradish peroxidase (EC 1.11.1.7) was either adsorbed onto the poly(aniline) film or immobilized in an insulating poly(1,2-diaminobenzene) polymer grown electrochemically on top of the poly(aniline) film to complete the device. In the completed device, the conductivity of the poly(aniline) film changes from conducting (between - 0.05 and + 0.3 V vs SCE at pH 5) to insulating (>+0.3 V vs SCE at pH 5) on addition of hydrogen peroxide. The change in conductivity is brought about by oxidation of the poly(aniline) film by direct electrochemical communication between the enzyme and the conducting polymer. This was confirmed by measuring the potential of the poly(aniline) film during switching of the conductivity in the presence of hydrogen peroxide. The devices can be reused by rereducing the poly(aniline) electrochemically to a potential below +0.3 V vs SCE. A blind test showed that the device can be used to determine unknown concentrations of H(2)O(2) in solution and that, when used with hydrogen peroxide concentrations below 0.5 mmol dm(-)(3), the same device maybe reused several times. The possible development of devices of this type for use in applications requiring the measurement of low levels of hydrogen peroxide or horseradish peroxidase is discussed.

Effects of dietary fats (fish, olive and high-oleic-acid sunflower oils) on lipid composition and antioxidant enzymes in rat liver.

PubMed

Ruiz-Gutiérrez, V; Pérez-Espinosa, A; Vázquez, C M; Santa-María, C

1999-09-01

The effects of two oleic-acid-rich diets (containing olive oil, OO, and high-oleic-acid sunflower oil, HOSO) on plasma and liver lipid composition detoxification enzyme activities, were compared with those of a fish-oil (FO) diet and a control diet. Compared with the control diet, plasma and hepatic total triacylglycerol concentrations were increased in the animals fed on the HOSO and OO diets and decreased in those fed on the FO diet. The animals fed on FO showed the highest level of cholesterol in the liver and had lower plasma cholesterol concentrations when compared with those fed on the two oleic-acid-rich diets. In comparison with the animals fed on the diets enriched in oleic acid, the FO group showed higher hepatic levels of polyunsaturated fatty acids of the n-3 series and lower levels of fatty acids of the n-6 series. Livers of FO-fed rats, compared with those of OO- and HOSO-fed rats showed: (1) significantly higher activities of catalase (EC 1.11.1.6) glutathione peroxidase (EC 1.11.1.9) and Cu/Zn superoxide dismutase (EC 1.15.1.1); (2) no differences in the NADPH-cytochrome c reductase (EC 1.6.99.3) activity. The HOSO diet had a similar effect on liver antioxidant enzyme activities as the OO diet. In conclusion, it appears that changes in the liver fatty acid composition due mainly to n-3 lipids may enhance the efficiency of the antioxidant defence system. The two monounsaturated fatty acids oils studied (OO and HOSO), with the same high content of oleic acid but different contents of natural antioxidants, had similar effects on the antioxidant enzyme activities measured.

Differential proteome analysis during early somatic embryogenesis in Musa spp. AAA cv. Grand Naine.

PubMed

Kumaravel, Marimuthu; Uma, Subbaraya; Backiyarani, Suthanthiram; Saraswathi, Marimuthu Somasundaram; Vaganan, Muthu Mayil; Muthusamy, Muthusamy; Sajith, Kallu Purayil

2017-01-01

Endogenous hormone secretion proteins along with stress and defense proteins play predominant role in banana embryogenesis. This study reveals the underlying molecular mechanism during transition from vegetative to embryogenic state. Banana (Musa spp.) is well known globally as a food fruit crop for millions. The requirement of quality planting material of banana is enormous. Although mass multiplication through tissue culture is in vogue, high-throughput techniques like somatic embryogenesis (SE) as a mass multiplication tool needs to be improved. Apart from clonal propagation, SE has extensive applications in genetic improvement and mutation. SE in banana is completely genome-dependent and most of the commercial cultivars exhibit recalcitrance. Thus, understanding the molecular basis of embryogenesis in Musa will help to develop strategies for mass production of quality planting material. In this study, differentially expressed proteins between embryogenic calli (EC) and non-embryogenic calli (NEC) with respect to the explant, immature male flower buds (IMFB), of cv. Grand Naine (AAA) were determined using two-dimensional gel electrophoresis (2DE). The 2DE results were validated through qRT-PCR. In total, 65 proteins were identified: 42 were highly expressed and 23 were less expressed in EC compared to NEC and IMFB. qRT-PCR analysis of five candidate proteins, upregulated in EC, were well correlated with expression at transcript level. Further analysis of proteins showed that embryogenesis in banana is associated with the control of oxidative stress. The regulation of ROS scavenging system and protection of protein structure occurred in the presence of heat shock proteins. Alongside, high accumulation of stress-related cationic peroxidase and plant growth hormone-related proteins like indole-3-pyruvate monooxygenase and adenylate isopentenyltransferase in EC revealed the association with the induction of SE.

Alleviation of ascorbic acid-induced gastric high acidity by calcium ascorbate in vitro and in vivo.

PubMed

Lee, Joon-Kyung; Jung, Sang-Hyuk; Lee, Sang-Eun; Han, Joo-Hui; Jo, Eunji; Park, Hyun-Soo; Heo, Kyung-Sun; Kim, Deasun; Park, Jeong-Sook; Myung, Chang-Seon

2018-01-01

Ascorbic acid is one of the most well-known nutritional supplement and antioxidant found in fruits and vegetables. Calcium ascorbate has been developed to mitigate the gastric irritation caused by the acidity of ascorbic acid. The aim of this study was to compare calcium ascorbate and ascorbic acid, focusing on their antioxidant activity and effects on gastric juice pH, total acid output, and pepsin secretion in an in vivo rat model, as well as pharmacokinetic parameters. Calcium ascorbate and ascorbic acid had similar antioxidant activity. However, the gastric fluid pH was increased by calcium ascorbate, whereas total acid output was increased by ascorbic acid. In the rat pylorus ligation-induced ulcer model, calcium ascorbate increased the gastric fluid pH without changing the total acid output. Administration of calcium ascorbate to rats given a single oral dose of 100 mg/kg as ascorbic acid resulted in higher plasma concentrations than that from ascorbic acid alone. The area under the curve (AUC) values of calcium ascorbate were 1.5-fold higher than those of ascorbic acid, and the C max value of calcium ascorbate (91.0 ng/ml) was higher than that of ascorbic acid (74.8 ng/ml). However, their T max values were similar. Thus, although calcium ascorbate showed equivalent antioxidant activity to ascorbic acid, it could attenuate the gastric high acidity caused by ascorbic acid, making it suitable for consideration of use to improve the side effects of ascorbic acid. Furthermore, calcium ascorbate could be an appropriate antioxidant substrate, with increased oral bioavailability, for patients with gastrointestinal disorders.

Alleviation of ascorbic acid-induced gastric high acidity by calcium ascorbate in vitro and in vivo

PubMed Central

Lee, Joon-Kyung; Jung, Sang-Hyuk; Lee, Sang-Eun; Han, Joo-Hui; Jo, Eunji; Park, Hyun-Soo; Heo, Kyung-Sun; Kim, Deasun

2018-01-01

Ascorbic acid is one of the most well-known nutritional supplement and antioxidant found in fruits and vegetables. Calcium ascorbate has been developed to mitigate the gastric irritation caused by the acidity of ascorbic acid. The aim of this study was to compare calcium ascorbate and ascorbic acid, focusing on their antioxidant activity and effects on gastric juice pH, total acid output, and pepsin secretion in an in vivo rat model, as well as pharmacokinetic parameters. Calcium ascorbate and ascorbic acid had similar antioxidant activity. However, the gastric fluid pH was increased by calcium ascorbate, whereas total acid output was increased by ascorbic acid. In the rat pylorus ligation-induced ulcer model, calcium ascorbate increased the gastric fluid pH without changing the total acid output. Administration of calcium ascorbate to rats given a single oral dose of 100 mg/kg as ascorbic acid resulted in higher plasma concentrations than that from ascorbic acid alone. The area under the curve (AUC) values of calcium ascorbate were 1.5-fold higher than those of ascorbic acid, and the Cmax value of calcium ascorbate (91.0 ng/ml) was higher than that of ascorbic acid (74.8 ng/ml). However, their Tmax values were similar. Thus, although calcium ascorbate showed equivalent antioxidant activity to ascorbic acid, it could attenuate the gastric high acidity caused by ascorbic acid, making it suitable for consideration of use to improve the side effects of ascorbic acid. Furthermore, calcium ascorbate could be an appropriate antioxidant substrate, with increased oral bioavailability, for patients with gastrointestinal disorders. PMID:29302210

The toxicity of N-methyl-alpha-methyldopamine to freshly isolated rat hepatocytes is prevented by ascorbic acid and N-acetylcysteine.

PubMed

Carvalho, Márcia; Remião, Fernando; Milhazes, Nuno; Borges, Fernanda; Fernandes, Eduarda; Carvalho, Félix; Bastos, Maria Lourdes

2004-08-05

In the past decade, clinical evidence has increasingly shown that the liver is a target organ for 3,4-methylenedioxymethamphetamine (MDMA, "ecstasy") toxicity. The aims of the present in vitro study were: (1) to evaluate and compare the hepatotoxic effects of MDMA and one of its main metabolites, N-methyl-alpha-methyldopamine (N-Me-alpha-MeDA) and (2) to investigate the ability of antioxidants, namely ascorbic acid and N-acetyl-L-cysteine (NAC), to prevent N-Me-alpha-MeDA-induced toxic injury, using freshly isolated rat hepatocytes. Cell suspensions were incubated with MDMA or N-Me-alpha-MeDA in the final concentrations of 0.1, 0.2, 0.4, 0.8, and 1.6 mM for 3 h. To evaluate the potential protective effects of antioxidants, cells were preincubated with ascorbic acid in the final concentrations of 0.1 and 0.5 mM, or NAC in the final concentrations of 0.1 and 1 mM for 15 min before treatment with 1.6 mM N-Me-alpha-MeDA for 3 h (throughout this incubation period the cells were exposed to both compounds). The toxic effects were evaluated by measuring the cell viability, glutathione (GSH) and glutathione disulfide (GSSG), ATP, and the cellular activities of GSH peroxidase (GPX), GSSG reductase (GR), and GSH S-transferase (GST). MDMA induced a concentration- and time-dependent GSH depletion, but had a negligible effect on cell viability, ATP levels, or on the activities of GR, GPX, and GST. In contrast, N-Me-alpha-MeDA was shown to induce not only a concentration- and time-dependent depletion of GSH, but also a depletion of ATP levels accompanied by a loss in cell viability, and decreases in the antioxidant enzyme activities. For both compounds, GSH depletion was not accompanied by increases in GSSG levels, which seems to indicate GSH depletion by adduct formation. Importantly, the presence of ascorbic acid (0.5 mM) or NAC (1 mM) prevented cell death and GSH depletion induced by N-Me-alpha-MeDA. The results provide evidence that MDMA and its metabolite N-Me-alpha-MeDA induce toxicity to freshly isolated rat hepatocytes. Oxidative stress may play a major role in N-Me-alpha-MeDA-induced hepatic toxicity since antioxidant defense systems are impaired and administration of antioxidants prevented N-Me-alpha-MeDA toxicity.

Hydrogen peroxide formation in cacao tissues infected by the hemibiotrophic fungus Moniliophthora perniciosa.

PubMed

Dias, Cristiano Villela; Mendes, Juliano Sales; dos Santos, Anderson Carvalho; Pirovani, Carlos Priminho; da Silva Gesteira, Abelmon; Micheli, Fabienne; Gramacho, Karina Peres; Hammerstone, John; Mazzafera, Paulo; de Mattos Cascardo, Júlio Cézar

2011-08-01

In plant-pathogen interaction, the hydrogen peroxide (H₂O₂) may play a dual role: its accumulation inhibits the growth of biotrophic pathogens, while it could help the infection/colonization process of plant by necrotrophic pathogens. One of the possible pathways of H₂O production involves oxalic acid (Oxa) degradation by apoplastic oxalate oxidase. Here, we analyzed the production of H₂O₂, the presence of calcium oxalate (CaOx) crystals and the content of Oxa and ascorbic acid (Asa)--the main precursor of Oxa in plants--in susceptible and resistant cacao (Theobroma cacao L.) infected by the hemibiotrophic fungus Moniliophthora perniciosa. We also quantified the transcript level of ascorbate peroxidase (Apx), germin-like oxalate oxidase (Glp) and dehydroascorbate reductase (Dhar) by RT-qPCR. We report that the CaOx crystal amount and the H₂O₂ levels in the two varieties present distinct temporal and genotype-dependent patterns. Susceptible variety accumulated more CaOx crystals than the resistant one, and the dissolution of these crystals occurred in the early infection steps and in the final stage of the disease in the resistant and the susceptible variety, respectively. High expression of the Glp and accumulation of Oxa were observed in the resistant variety. The content of Asa increased in the inoculated susceptible variety, but remained constant in the resistant one. The susceptible variety presented reduced Dhar expression. The role of H₂O₂ and its formation from Oxa via Apx and Glp in resistant and susceptible variety infected by M. perniciosa were discussed. Copyright © 2011 Elsevier Masson SAS. All rights reserved.

Reactive Oxygen Species Tune Root Tropic Responses1[OPEN

PubMed Central

Krieger, Gat

2016-01-01

The default growth pattern of primary roots of land plants is directed by gravity. However, roots possess the ability to sense and respond directionally to other chemical and physical stimuli, separately and in combination. Therefore, these root tropic responses must be antagonistic to gravitropism. The role of reactive oxygen species (ROS) in gravitropism of maize and Arabidopsis (Arabidopsis thaliana) roots has been previously described. However, which cellular signals underlie the integration of the different environmental stimuli, which lead to an appropriate root tropic response, is currently unknown. In gravity-responding roots, we observed, by applying the ROS-sensitive fluorescent dye dihydrorhodamine-123 and confocal microscopy, a transient asymmetric ROS distribution, higher at the concave side of the root. The asymmetry, detected at the distal elongation zone, was built in the first 2 h of the gravitropic response and dissipated after another 2 h. In contrast, hydrotropically responding roots show no transient asymmetric distribution of ROS. Decreasing ROS levels by applying the antioxidant ascorbate, or the ROS-generation inhibitor diphenylene iodonium attenuated gravitropism while enhancing hydrotropism. Arabidopsis mutants deficient in Ascorbate Peroxidase 1 showed attenuated hydrotropic root bending. Mutants of the root-expressed NADPH oxidase RBOH C, but not rbohD, showed enhanced hydrotropism and less ROS in their roots apices (tested in tissue extracts with Amplex Red). Finally, hydrostimulation prior to gravistimulation attenuated the gravistimulated asymmetric ROS and auxin signals that are required for gravity-directed curvature. We suggest that ROS, presumably H2O2, function in tuning root tropic responses by promoting gravitropism and negatively regulating hydrotropism. PMID:27535793

Influence of ageing process on body composition of antioxidant and lipid peroxidation among healthy individuals in South West Nigeria.

PubMed

Ogunro, P S; Ogungbamigbe, T O

2013-03-01

To evaluate the effect of ageing on the level of antioxidants and lipid peroxidation in healthy individual of various age groups. A total number of 162 healthy males and females volunteer between the ages of 18-80 years were divided into three groups. These volunteers were divided into group i(18-30 yr), group ii (31-60 yrs) and group iii (60-80 yr). Plasma concentration of total bilirubin, uric acid, ascorbic acid, a-tocopherol, retinol, total antioxidant status (TAS), malondialdehyde (MDA), glutathione (GSH) and ceruloplasmin measured. Erythrocyte antioxidant enzyme activities of superoxide dismutase (SOD), catalase (CAT), glutathione and peroxidase (GSHPx) were measured using standard methods. Erythrocyte antioxidant enzymes (GSH-Px and SOD) activities and GSH level were significantly reduced among group iii (p<0.01) and group ii (p<0.05) age group subjects compared to the younger age group i. Conversely, MDA showed a significant increase in group iii (p<0.01) and group ii (p<0.01) compared to younger age group i. CAT activity and TAS level were reduced significantly (p<0.05) in both groups iii and ii compared to younger age group i. Ascorbic acid, a-tocopherol and retinol levels were significantly reduced among group iii (p<0.05) compared to group i. Ageing was associated with increased lipid peroxidation and lower antioxidant defenses. Changes that occur during ageing cannot be avoided but may be delayed and controlled to some extent. To counter these changes, dietary supplementation of a variety of antioxidants might be beneficial.

Antioxidant defense and apoptotic effectors in ascorbic acid and β-glycerophosphate-induced osteoblastic differentiation.

PubMed

Chaves Neto, Antonio Hernandes; Machado, Daisy; Yano, Cláudia Lumy; Ferreira, Carmen Veríssima

2011-01-01

MC3T3-E1 cells grown in the presence of ascorbic acid and β-glycerophosphate (AA/β-GP) express alkaline phosphatase and produce an extensive collagenous extracellular matrix. Differentiated MC3T3-E1 cells are more sensitive to hydrogen peroxide-induced oxidative stress than undifferentiated cells. In this study, we compared the profile of antioxidant enzymes and molecular markers of apoptosis in undifferentiated and differentiated MC3T3-E1 cells (cell differentiation was induced by treatment with AA/β-GP). Differentiated osteoblasts showed lower expression and activity of catalase, glutathione S-transferase and glutathione peroxidase. The total superoxide dismutase activity and the expression of Cu/Zn superoxide dismutase were also lower, while the expression of Mn superoxide dismutase was higher in differentiated osteoblasts. The level of malondialdehyde, a widely used marker for oxidative stress, was lower in the AA/β-GP group compared with control cells, but this difference was not significant. Western blotting showed that treatment with AA/β-GP increased the Bax/Bcl-2 ratio used as an index of cellular vulnerability to apoptosis. In addition, the activities of caspases 3, 8 and 9 and cleaved poly (ADP) ribose polymerase were significantly higher in differentiated cells. These findings provide new insights into how changes in the activities of major antioxidant enzymes and in the signaling pathways associated with apoptosis may influence the susceptibility of bone cells to oxidative stress. © 2011 The Authors. Journal compilation © 2011 Japanese Society of Developmental Biologists.

Photosynthetic response to low sink demand after fruit removal in relation to photoinhibition and photoprotection in peach trees.

PubMed

Duan, Wei; Fan, Pei G; Wang, Li J; Li, Wei D; Yan, Shu T; Li, Shao H

2008-01-01

Diurnal variations in photosynthesis, chlorophyll fluorescence, xanthophyll cycle, antioxidant enzymes and antioxidant metabolism in leaves in response to low sink demand caused by fruit removal (-fruit) were studied in 'Zaojiubao' peach (Prunus persica (L.) Batch) trees during the final stage of rapid fruit growth. Compared with the retained fruit treatment (+fruit), the -fruit treatment resulted in a significantly lower photosynthetic rate, stomatal conductance and transpiration rate, but generally higher internal CO(2) concentration, leaf-to-air vapor pressure difference and leaf temperature. The low photosynthetic rate in the -fruit trees paralleled reductions in maximal efficiency of photosystem II (PSII) photochemistry and carboxylation efficiency. The midday depression in photosynthetic rate in response to low sink demand resulting from fruit removal was mainly caused by non-stomatal limitation. Fruit removal resulted in lower quantum efficiency of PSII as a result of both a decrease in the efficiency of excitation capture by open PSII reaction centers and an increase in closure of PSII reaction centers. Both xanthophyll-dependent thermal dissipation and the antioxidant system were up-regulated providing protection from photo-oxidative damage to leaves during low sink demand. Compared with the leaves of +fruit trees, leaves of -fruit trees had a larger xanthophyll cycle pool size and a higher de-epoxidation state, as well as significantly higher activities of antioxidant enzymes, including superoxide dismutase, ascorbate peroxidase, monodehydroascorbate reductase, dehydroascorbate reductase, glutathione reductase and a higher reduction state of ascorbate and glutathione. However, the -fruit treatment resulted in higher hydrogen peroxide and malondialdehyde concentrations compared with the +fruit treatment, indicating photo-oxidative damage.

Ascorbic Acid Efflux from Human Brain Microvascular Pericytes: Role of Re-uptake

PubMed Central

May, James M.; Qu, Zhi-chao

2015-01-01

Microvascular pericytes take up ascorbic acid on the ascorbate transporter SVCT2. Intracellular ascorbate then protects the cells against apoptosis induced by culture at diabetic glucose concentrations. To investigate whether pericytes might also provide ascorbate to the underlying endothelial cells, we studied ascorbate efflux from human pericytes. When loaded with ascorbate to intracellular concentrations of 0.8–1.0 mM, almost two-thirds of intracellular ascorbate effluxed from the cells over 2 h. This efflux was opposed by ascorbate re-uptake from the medium, since preventing re-uptake by destroying extracellular ascorbate with ascorbate oxidase increased ascorbate loss even further. Ascorbate re-uptake occurred on the SVCT2, since its blockade by replacing medium sodium with choline, by the SVCT2 inhibitor sulfinpyrazone, or by extracellular ascorbate accelerated ascorbate loss from the cells. This was supported by finding that net efflux of radiolabeled ascorbate was increased by unlabeled extracellular ascorbate with a half-maximal effect in the range of the high affinity Km of the SVCT2. Intracellular ascorbate did not inhibit its efflux. To assess the mechanism of ascorbate efflux, known inhibitors of volume-regulated anion channels (VRACs) were tested. These potently inhibited ascorbate transport into cells on the SVCT2, but not its efflux. An exception was the anion transport inhibitor DIDS, which, despite inhibition of ascorbate uptake, also inhibited net efflux at 25–50 µM. These results suggest that ascorbate efflux from vascular pericytes occurs on a DIDS-inhibitable transporter or channel different from VRACs. Further, ascorbate efflux is opposed by re-uptake of ascorbate on the SVCT2, providing a potential regulatory mechanism. PMID:26340060

Common tea formulations modulate in vitro digestive recovery of green tea catechins.

PubMed

Green, Rodney J; Murphy, Angus S; Schulz, Burkhard; Watkins, Bruce A; Ferruzzi, Mario G

2007-09-01

Epidemiological evidence suggests a role for tea catechins in reduction of chronic disease risk. However, stability of catechins under digestive conditions is poorly understood. The objective of this study was to characterize the effect of common food additives on digestive recovery of tea catechins. Green tea water extracts were formulated in beverages providing 4.5, 18, 23, and 3.5 mg per 100 mL epicatechin (EC), epigallocatechin (EGC), epigallocatechin-gallate (EGCG), and epicatechin-gallate (ECG), respectively. Common commercial beverage additives; citric acid (CA), BHT, EDTA, ascorbic acid (AA), milk (bovine, soy, and rice), and citrus juice (orange, grapefruit, lemon, and lime) were formulated into finished tea beverages at incremental dosages. Samples were then subjected to in vitro digestion simulating gastric and small intestinal conditions with pre- and post-digestion catechin profiles assessed by HPLC. Catechin stability in green tea was poor with <20% total catechins remaining post-digestion. EGC and EGCG were most sensitive with less, not double equals 10% recovery. Teas formulated with 50% bovine, soy, and rice milk increased total catechin recovery significantly to 52, 55, and 69% respectively. Including 30 mg AA in 250 mL of tea beverage significantly (p<0.05) increased catechin recovery of EGC, EGCG, EC, and ECG to 74, 54, 82, and 45% respectively. Juice preparation resulted in the highest recovery of any formulation for EGC (81-98%), EGCG (56-76%), EC (86-95%), and ECG (30-55%). These data provide evidence that tea consumption practices and formulation factors likely impact catechin digestive recovery and may result in diverse physiological profiles.

Effects of an anti-oxidative ACAT inhibitor on apoptosis/necrosis and cholesterol accumulation under oxidative stress in THP-1 cell-derived foam cells.

PubMed

Miike, Tomohiro; Shirahase, Hiroaki; Jino, Hiroshi; Kunishiro, Kazuyoshi; Kanda, Mamoru; Kurahashi, Kazuyoshi

2008-01-02

THP-1 cell-derived foam cells were exposed to oxidative stress through combined treatment with acetylated LDL (acLDL) and copper ions (Cu2+). The foam cells showed caspase-dependent apoptotic changes on exposure to oxidative stress for 6 h, and necrotic changes with the leakage of LDH after 24 h. KY-455, an anti-oxidative ACAT inhibitor, and ascorbic acid (VC) but not YM-750, an ACAT inhibitor, prevented apoptotic and necrotic changes. These preventive effects of KY-455 and VC were accompanied by the inhibition of lipid peroxidation in culture medium containing acLDL and Cu2+, suggesting the involvement of oxidized acLDL in apoptosis and necrosis. Foam cells accumulated esterified cholesterol (EC) for 24 h in the presence of acLDL without Cu2+, which was suppressed by KY-455 and YM-750. Foam cells showed necrotic changes and died in the presence of acLDL and Cu2+. KY-455 but not YM-750 prevented cell death and reduced the amount of EC accumulated. The foam cells treated with VC further accumulated EC without necrotic changes for 24 h even in the presence of acLDL and Cu2+. YM-750 as well as KY-455 inhibited lipid accumulation when co-incubated with VC in foam cells exposed to oxidative stress. It is concluded that an anti-oxidative ACAT inhibitor or the combination of an antioxidant and an ACAT inhibitor protects foam cells from oxidative stress and effectively reduces cholesterol levels, which would be a promising approach in anti-atherosclerotic therapy.

The mechanisms of protection of antioxidants on Nostoc sphaeroides against UV-B radiation

NASA Astrophysics Data System (ADS)

Wang, G. H.

UV radiation is one of space harmful factor for earth organisms in space exploration In the present work we studied on the role of antioxidant system in Nostoc sphaeroides K u tz Cyanobacteria and the effects of exogenous antioxidant molecules on its photosynthetic rate under UV-B radiation It was found that UV-B radiation decreased the photosynthetic activity of cyanobacterium but promoted the activity of antioxidant system to protect photosystem II PSII and exogenous antioxidant sodium nitroprusside SNP N-acetylcysteine NAC had an obvious protection on PSII activity under UV-B radiation The activity of SOD Superoxide Dismutase EC 1 15 1 1 CAT Catalase EC 1 11 1 6 POD Peroxidase EC 1 11 1 7 and content of MDA and ASC were improved by 0 5mM and 1mM SNP but 0 1mM SNP decreased the activity of antioxide system Exogenous NAC addition decreased the activity of SOD POD CAT and the content MDA and ASC but exogenous NAC addition increased the content of GSH The results suggested that exogenous SNP and NAC may protect algae by different mechanisms in which SNP maybe play double roles as sources of reactive free radicals or ROS scavengers in formation of algae s protection of PSII under UV-B radiation while NAC does function as antioxidant reagent or precursor of glutathione which could protect PSII directly from UV-B radiation Keyword antioxidant system exogenous or endogenous antioxidant Nostoc sphaeroides photosynthesis UV-B radiation

Phenyl derivative of pyranocoumarin precludes Fusarium oxysporum f.sp. Lycopersici infection in Lycopersicon esculentum via induction of enzymes of the phenylpropanoid pathway.

PubMed

Sangeetha, S; Sarada, D V L

2015-01-01

Binding of phenyl derivative of pyranocoumarin (PDP) modulated activity of fungal endopolygalacturonase in silico. Induced fit docking study of PDP with endopolygalacturonase (1HG8) showed a bifurcated hydrogen bond interaction with the protein at Lys 244 with a docking score of -3.6 and glide energy of -37.30 kcal/mol. Docking with endopolygalacturonase II (1CZF) resulted hydrogen bond formation with Lys 258 with a docking score of -2.3 and glide energy of -30.42 kcal/mol. It was hypothesized that this modulation favors accumulation of cell wall fragments (oligogalacturonides) which act as elicitors of plant defense responses. In order to prove the same, in vivo studies were carried out using a formulation developed from PDP (PDP 5EC) on greenhouse grown Lycopersicon esculentum L. The formulation was effective at different concentrations in reduction of seed infection, improvement of vigor and control of Fusarium oxysporum f.sp. lycopersici infection in L. esculentum. At a concentration of 2 %, PDP 5EC significant reduction in seed infection (95.83 %), improvement in seed vigor (64.31 %) and control of F. oxysporum f.sp. lycopersici infection (96.15 %) were observed. Further application of PDP 5EC to L. esculentum challenged with F. oxysporum f.sp. lycopersici significantly increased the activity of enzymes of the phenylpropanoid pathway, namely, peroxidase (PO), polyphenol oxidase (PPO), phenylalanine ammonia lyase (PAL), and enhanced the total phenolic content when compared to the control.

Response of ligninolytic macrofungi to the herbicide atrazine: dose-response bioassays.

PubMed

Cupul, Wilberth Chan; Abarca, Gabriela Heredia; Vázquez, Refugio Rodríguez; Salmones, Dulce; Hernández, Rigoberto Gaitán; Gutiérrez, Enrique Alarcón

2014-01-01

The effect of atrazine concentrations on mycelial growth and ligninolytic enzyme activities of eight native ligninolytic macrofungi isolated in Veracruz, México, were evaluated in a semi-solid culture medium. Inhibition of mycelial growth and growth rates were significantly affected (p=0.05) by atrazine concentrations (468, 937, 1875, and 3750 mg/l). In accordance with the median effective concentration (EC50), Pleurotus sp. strain 1 proved to be the most tolerant isolate to atrazine (EC50=2281.0 mg/l), although its enzyme activity was not the highest. Pycnoporus sanguineus strain 2, Daedalea elegans and Trametes maxima showed high laccase activity (62.7, 31.9, 29.3 U mg/protein, respectively) without atrazine (control); however, this activity significantly increased (p<0.05) (to 191.1, 83.5 and 120.6 U mg/protein, respectively) owing to the effect of atrazine (937 mg/l) in the culture medium. Pleurotus sp. strain 2 and Cymatoderma elegans significantly increased (p<0.05) their manganese peroxidase (MnP) activities under atrazine stress at 468 mg/l. The isolates with high EC50 (Pleurotus sp. strain 1) and high enzymatic activity (P. sanguineus strain 2 and T. maxima) could be considered for future studies on atrazine mycodegradation. Furthermore, this study confirms that atrazine can increase laccase and MnP activities in ligninolytic macrofungi. Copyright © 2014 Asociación Argentina de Microbiología. Publicado por Elsevier España. All rights reserved.

Ascorbic Acid Efflux and Re-uptake in Endothelial Cells: Maintenance of Intracellular Ascorbate

PubMed Central

May, James M.; Qu, Zhi-chao

2013-01-01

Entry of vitamin C or ascorbate into most tissues requires its movement across the endothelial cell barrier of vessels. If trans-cellular ascorbate movement occurs, then it should be evident as ascorbate efflux from endothelial cells. Cultured EA.926 endothelial cells that had been loaded to about 3.5 mM intracellular ascorbate lost 70–80% of ascorbate to the medium over several hours at 37 °C via a non-saturable process that was insensitive to anion transport inhibitors and thiol reagents. Oxidation of this extracellular ascorbate by ascorbate oxidase or ferricyanide enhanced apparent ascorbate efflux, suggesting that efflux of the vitamin was countered in part by its re-uptake on ascorbate transporters. Although basal ascorbate efflux was not calcium-dependent, increased entry of calcium into the cells enhanced ascorbate release. These results support the hypothesis that ascorbate efflux reflects trans-endothelial cell ascorbate movement out of the blood vessel. PMID:19148707

Ascorbic acid efflux and re-uptake in endothelial cells: maintenance of intracellular ascorbate.

PubMed

May, James M; Qu, Zhi-chao

2009-05-01

Entry of vitamin C or ascorbate into most tissues requires its movement across the endothelial cell barrier of vessels. If trans-cellular ascorbate movement occurs, then it should be evident as ascorbate efflux from endothelial cells. Cultured EA.926 endothelial cells that had been loaded to about 3.5 mM intracellular ascorbate lost 70-80% of ascorbate to the medium over several hours at 37 degrees C via a non-saturable process that was insensitive to anion transport inhibitors and thiol reagents. Oxidation of this extracellular ascorbate by ascorbate oxidase or ferricyanide enhanced apparent ascorbate efflux, suggesting that efflux of the vitamin was countered in part by its re-uptake on ascorbate transporters. Although basal ascorbate efflux was not calcium-dependent, increased entry of calcium into the cells enhanced ascorbate release. These results support the hypothesis that ascorbate efflux reflects trans-endothelial cell ascorbate movement out of the blood vessel.

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

PubMed

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 in tomato plants at low temperatures.

Endosulfan induced biochemical changes in nitrogen-fixing cyanobacteria.

PubMed

Kumar, Satyendra; Habib, Khalid; Fatma, Tasneem

2008-09-15

Pesticide contamination in aquatic ecosystem including paddy fields is a serious global environmental concern. Cyanobacteria are also affected by pesticides as non- target organism. For better exploitation of cyanobacteria as biofertiliser, it is indispensable to select tolerant strains along with understanding of their tolerance. Three cyanobacterial strains viz. Aulosira fertilissima, Anabaena variabilis and Nostoc muscorum were studied for their stress responses to an organochlorine pesticide 'endosulfan' with special reference to oxidative stress, role of proline and antioxidant enzymes in endosulfan induced free radical detoxification. Reduction in growth, photosynthetic pigments and carbohydrate of the test microorganisms were accompanied with increase in their total protein, proline, malondialdehye (MDA), superoxide dismutase (SOD), ascorbate peroxidase (APX) and catalase (CAT) in higher endosulfan doses. Increased amount of MDA is indicative of formation of free radicals, while increased level of CAT, APX, SOD and proline indicated their involvement in free radical scavenging mechanism. In lower concentrations, test pesticide showed increase in photosynthetic pigments. Order of tolerance was Nostoc muscorum>Anabaena variabilis>Aulosira fertilissima.

Blood antioxidant parameters in patients with diabetic retinopathy.

PubMed

Siemianowicz, Krzysztof; Gminski, Jan; Telega, Alicja; Wójcik, Aneta; Posielezna, Barbara; Grabowska-Bochenek, Rozalia; Francuz, Tomasz

2004-09-01

It has been postulated that enhanced generation of reactive oxygen species (ROS) may take part in a pathogenesis of diabetic microvascular complication - retinopathy. There are two types of diabetic retinopathy, non-proliferative (simplex) and proliferative. ROS are anihilated by an intracelluar enzymatic system composed mainly of glutathione peroxidase (GPx), superoxide dismutase (SOD) and catalase (CAT). Beta-carotene, tocopherols and ascorbic acid are major components of serum antioxidants. All serum antioxidants are usually measured together as total antioxidant status (TAS). Erythrocyte activities of GPx, SOD, CAT and TAS were measured in diabetic patients without retinopathy, with non-proliferative and proliferative retinopathy. Obtained results were correlated with a period of diabetic history and a period of insulin treatment. SOD was significantly elevated in diabetics with non-proliferative retinopathy compared to patients without retinopathy. TAS was significantly lower in patients with proliferative retinopathy than in diabetics not developing retinopathy. Only CAT was significantly negatively correlated with the period of insulin treatment. This significant negative correlation was also observed in a subgroup of patients with proliferative retinopathy.

Suitability of combination of calcium propionate and chitosan for preserving minimally processed banana quality.

PubMed

Mirshekari, Amin; Madani, Babak; Golding, John B

2017-08-01

The marketability of fresh-cut banana slices is limited by the rapid rate of fruit softening and browning. However, there is no scientific literature available about the role of postharvest calcium propionate and chitosan treatment on the quality attributes of fresh-cut banana. Therefore, the aim of the present study was to investigate these effects. The application of calcium propionate plus chitosan (CaP+Chit) retained higher firmness, higher ascorbic acid content, higher total antioxidant activity and higher total phenolic compounds, along with lower browning, lower polyphenol oxidase, lower peroxidase, lower polygalacturonase and lower pectin methyl esterase activities and microbial growth, compared to control banana slices after 5 days of cold storage. The results of the present study show that CaP+Chit could be used to slow the loss of quality at the same time as maintaining quality and inhibiting microbial loads. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Enhancing safety and shelf life of fresh-cut mango by application of edible coatings and microencapsulation technique.

PubMed

Alikhani, Majid

2014-05-01

Mango pulp is very perishable and so has a short shelf life, which both marketers and consumers would like to be longer. Manually sliced mango was treated by coating opuntia mucilage-rosemary oil (Mu + RO), 2 g rosemary oil microencapsul (ROM), and 2 g (ROM) plus (Mu + RO); the treated mango pieces were placed in plastic trays, and overwrapped with PVDC film and then stored at 6°C. Changes in the quality parameters and activity of peroxidase (POD) enzyme were evaluated for 9 days of storage period. These treatments retarded loss of ascorbic acid and the drop in sensory acceptability, fewer changes in color, decreasing activity POD enzyme. These also inhibited the decay incidence and slowed microbial growth. The (Mu + RO) treatment was more effective in controlling postharvest quality as compared to the (ROM) treatment, but the data reveal that applying the compound treatment effectively prolongs the quality attributes and extends the storage life of sliced mango fruit.

Phosphorus improves arsenic phytoremediation by Anadenanthera peregrina by alleviating induced oxidative stress.

PubMed

Gomes, M P; Carvalho, M; Carvalho, G S; Marques, T C L L S M; Garcia, Q S; Guilherme, L R G; Soares, A M

2013-01-01

Due to similarities in their chemical behaviors, studies examining interactions between arsenic (As)--in special arsenate--and phosphorus (P) are important for better understanding arsenate uptake, toxicity, and accumulation in plants. We evaluated the effects of phosphate addition on plant biomass and on arsenate and phosphate uptake by Anadenanthera peregrina, an important Brazilian savanna legume. Plants were grown for 35 days in substrates that received combinations of 0, 10, 50, and 100 mg kg(-1) arsenate and 0, 200, and 400 mg kg(-1) phosphate. The addition of P increased the arsenic-phytoremediation capacity of A. peregrina by increasing As accumulation, while also alleviating As-induced oxidative stress. Arsenate phytotoxicity in A. peregrina is due to lipid peroxidation, but not hydrogen peroxide accumulation. Added P also increased the activity of important reactive oxygen species-scavenging enzymes (catalase and ascorbate peroxidase) that help prevent lipid peroxidation in leaves. Our findings suggest that applying P represents a feasible strategy for more efficient As phytoremediation using A. peregrina.

Improved tolerance to transplanting injury and chilling stress in rice seedlings treated with orysastrobin.

PubMed

Takahashi, Naoto; Sunohara, Yukari; Fujiwara, Masami; Matsumoto, Hiroshi

2017-04-01

In addition to their fungicidal activity, strobilurin-type fungicides are reported to show enhancing effects on crop growth and yield. Previous studies suggested that the fungicide has a mitigating effect on abiotic stresses. However, there are few reports about growth enhancement through abiotic stress alleviation by strobilurin-type fungicides, but the mechanism of action of the growth enhancement is still not clear. The present study revealed that orysastrobin enhanced rice seedling growth after root cutting injury and chilling stress. We also found that orysastrobin decreased the transpiration rate and increased ascorbate peroxidase and glutathione reductase activities. This stress alleviation was eliminated by the application of naproxen, a putative abscisic acid biosynthesis inhibitor. These results suggested that orysastrobin improved tolerance against transplanting injury and chilling stress in rice seedlings by inducing water-retaining activity through the suppression of transpiration, and also by inducing reactive oxygen scavenging activity thus inhibiting reactive oxygen species accumulation. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Biochemical basis of 4-hydroxyanisole induced cell toxicity towards B16-F0 melanoma cells.

PubMed

Moridani, Majid Y

2006-11-18

In the current work we investigated for the first time the biochemical basis of 4-hydroxyanisole (4-HA) induced toxicity in B16-F0 melanoma cells. It was found that dicoumarol, a diaphorase inhibitor, and 1-bromoheptane, a GSH depleting agent, increased 4-HA induced toxicity towards B16-F0 cells whereas dithiothreitol, a thiol containing agent, and ascorbic acid (AA), a reducing agent, largely prevented 4-HA toxicity. TEMPOL and pyrogallol, free radical scavengers, did not significantly prevent 4-HA toxicity towards B16-F0 cells. GSH>AA>NADH prevented the o-quinone formation when 4-HA was metabolized by tyrosinase/O(2). 4-HA metabolism by horseradish peroxidase/H(2)O(2) was prevented more effectively by AA than NADH>GSH. We therefore concluded that quinone formation was the major pathway for 4-HA induced toxicity in B16-F0 melanoma cells whereas free radical formation played a negligible role in the 4-HA induced toxicity.

Enhancing safety and shelf life of fresh-cut mango by application of edible coatings and microencapsulation technique

PubMed Central

Alikhani, Majid

2014-01-01

Mango pulp is very perishable and so has a short shelf life, which both marketers and consumers would like to be longer. Manually sliced mango was treated by coating opuntia mucilage-rosemary oil (Mu + RO), 2 g rosemary oil microencapsul (ROM), and 2 g (ROM) plus (Mu + RO); the treated mango pieces were placed in plastic trays, and overwrapped with PVDC film and then stored at 6°C. Changes in the quality parameters and activity of peroxidase (POD) enzyme were evaluated for 9 days of storage period. These treatments retarded loss of ascorbic acid and the drop in sensory acceptability, fewer changes in color, decreasing activity POD enzyme. These also inhibited the decay incidence and slowed microbial growth. The (Mu + RO) treatment was more effective in controlling postharvest quality as compared to the (ROM) treatment, but the data reveal that applying the compound treatment effectively prolongs the quality attributes and extends the storage life of sliced mango fruit. PMID:24936290

A versatile nanobody-based toolkit to analyze retrograde transport from the cell surface.

PubMed

Buser, Dominik P; Schleicher, Kai D; Prescianotto-Baschong, Cristina; Spiess, Martin

2018-06-18

Retrograde transport of membranes and proteins from the cell surface to the Golgi and beyond is essential to maintain homeostasis, compartment identity, and physiological functions. To study retrograde traffic biochemically, by live-cell imaging or by electron microscopy, we engineered functionalized anti-GFP nanobodies (camelid VHH antibody domains) to be bacterially expressed and purified. Tyrosine sulfation consensus sequences were fused to the nanobody for biochemical detection of trans -Golgi arrival, fluorophores for fluorescence microscopy and live imaging, and APEX2 (ascorbate peroxidase 2) for electron microscopy and compartment ablation. These functionalized nanobodies are specifically captured by GFP-modified reporter proteins at the cell surface and transported piggyback to the reporters' homing compartments. As an application of this tool, we have used it to determine the contribution of adaptor protein-1/clathrin in retrograde transport kinetics of the mannose-6-phosphate receptors from endosomes back to the trans -Golgi network. Our experiments establish functionalized nanobodies as a powerful tool to demonstrate and quantify retrograde transport pathways.

A set of GFP-based organelle marker lines combined with DsRed-based gateway vectors for subcellular localization study in rice (Oryza sativa L.).

PubMed

Wu, Tsung-Meng; Lin, Ke-Chun; Liau, Wei-Shiang; Chao, Yun-Yang; Yang, Ling-Hung; Chen, Szu-Yun; Lu, Chung-An; Hong, Chwan-Yang

2016-01-01

In the post-genomic era, many useful tools have been developed to accelerate the investigation of gene functions. Fluorescent proteins have been widely used as protein tags for studying the subcellular localization of proteins in plants. Several fluorescent organelle marker lines have been generated in dicot plants; however, useful and reliable fluorescent organelle marker lines are lacking in the monocot model rice. Here, we developed eight different GFP-based organelle markers in transgenic rice and created a set of DsRed-based gateway vectors for combining with the marker lines. Two mitochondrial-localized rice ascorbate peroxidase genes fused to DsRed and successfully co-localized with mitochondrial-targeted marker lines verified the practical use of this system. The co-localization of GFP-fusion marker lines and DsRed-fusion proteins provide a convenient platform for in vivo or in vitro analysis of subcellular localization of rice proteins.

The effect of ultraviolet treatment on enzymatic activity and total phenolic content of minimally processed potato slices.

PubMed

Teoh, Li Shing; Lasekan, Ola; Adzahan, Noranizan Mohd; Hashim, Norhashila

2016-07-01

In this work, potato slices were exposed to different doses of UV-C irradiation (i.e. 2.28, 6.84, 11.41, and 13.68 kJ m -2 ) with or without pretreatment [i.e. ascorbic acid and calcium chloride (AACCl) dip] and stored at 4 ± 1 °C. Changes in enzymatic activities of polyphenol oxidase (PPO), peroxidase (POD) and phenylalanine ammonia lyase (PAL), as well as total phenolic content (TPC) were investigated after 0, 3, 7 and 10 days of storage. Results showed that untreated and UV-C treated potato slices at 13.68 kJ m -2 dosage level showed significantly higher PPO, POD and PAL activities. Conversely, untreated potato slices showed the lowest TPC during storage period. Potato slices subjected to AACCl dip plus UV-C at 6.84 kJ m -2 produced lower PPO, POD and PAL activities, as well as maintained a high TPC during storage.

Salinity induced oxidative stress enhanced biofuel production potential of microalgae Scenedesmus sp. CCNM 1077.

PubMed

Pancha, Imran; Chokshi, Kaumeel; Maurya, Rahulkumar; Trivedi, Khanjan; Patidar, Shailesh Kumar; Ghosh, Arup; Mishra, Sandhya

2015-01-01

Microalgal biomass is considered as potential feedstock for biofuel production. Enhancement of biomass, lipid and carbohydrate contents in microalgae is important for the commercialization of microalgal biofuels. In the present study, salinity stress induced physiological and biochemical changes in microalgae Scenedesmus sp. CCNM 1077 were studied. During single stage cultivation, 33.13% lipid and 35.91% carbohydrate content was found in 400 mM NaCl grown culture. During two stage cultivation, salinity stress of 400 mM for 3 days resulted in 24.77% lipid (containing 74.87% neutral lipid) along with higher biomass compared to single stage, making it an efficient strategy to enhance biofuel production potential of Scenedesmus sp. CCNM 1077. Apart from biochemical content, stress biomarkers like hydrogen peroxide, lipid peroxidation, ascorbate peroxidase, proline and mineral contents were also studied to understand the role of reactive oxygen species (ROS) mediated lipid accumulation in microalgae Scenedesmus sp. CCNM 1077. Copyright © 2015 Elsevier Ltd. All rights reserved.

Eucalyptus tolerance mechanisms to lanthanum and cerium: subcellular distribution, antioxidant system and thiol pools.

PubMed

Shen, Yichang; Zhang, Shirong; Li, Sen; Xu, Xiaoxun; Jia, Yongxia; Gong, Guoshu

2014-12-01

Guanglin 9 (Eucalyptus grandis × Eucalyptus urophlla) and Eucalyptus grandis 5 are two eucalyptus species which have been found to grow normally in soils contaminated with lanthanum and cerium, but the tolerance mechanisms are not clear yet. In this study, a pot experiment was conducted to investigate the tolerance mechanisms of the eucalyptus to lanthanum and cerium. Cell walls stored 45.40-63.44% of the metals under lanthanum or cerium stress. Peroxidase and catalase activities enhanced with increasing soil La or Ce concentrations up to 200 mg kg(-1), while there were no obvious changes in glutathione and ascorbate concentrations. Non-protein thiols concentrations increased with increasing treatment levels up to 200 mg kg(-1), and then decreased. Phytochelatins concentrations continued to increase under La or Ce stress. Therefore, the two eucalyptus species are La and Ce tolerant plants, and the tolerance mechanisms include cell wall deposition, antioxidant system response, and thiol compound synthesis. Copyright © 2014 Elsevier Ltd. All rights reserved.

Tyrosol and its metabolites as antioxidative and anti-inflammatory molecules in human endothelial cells.

PubMed

Muriana, Francisco J G; Montserrat-de la Paz, Sergio; Lucas, Ricardo; Bermudez, Beatriz; Jaramillo, Sara; Morales, Juan C; Abia, Rocio; Lopez, Sergio

2017-08-01

Tyrosol (Tyr) is a phenolic compound found in virgin olive oil. After ingestion, Tyr undergoes extensive first pass intestinal/hepatic metabolism. However, knowledge about the biological effects of Tyr metabolites is scarce. We chemically synthesized Tyr glucuronate (Tyr-GLU) and sulphate (Tyr-SUL) metabolites and explored their properties against oxidative stress and inflammation in TNF-α-treated human umbilical vein endothelial cells (hECs). Tyr and Tyr-SUL prevented the rise of reactive oxygen species, the depletion of glutathione, and the down-regulation of glutathione peroxidase 1, glutamate-cysteine ligase catalytic subunit, and heme oxygenase-1 genes. Tyr-SUL and to a lower extent Tyr and Tyr-GLU prevented the phosphorylation of NF-κB signaling proteins. Tyr-GLU and Tyr-SUL also prevented the over-expression of adhesion molecules at gene, protein, and secretory levels, and the adhesion (Tyr-SUL > Tyr-GLU) of human monocytes to hECs. In vivo, Tyr, and most notably Tyr-SUL in a dose-dependent manner, ameliorated plantar and ear edemas in mice models of acute and chronic inflammation. This study demonstrates the antioxidant and/or anti-inflammatory properties of Tyr metabolites, with Tyr-SUL being the most effective.

Diamine oxidase is involved in H(2)O(2) production in the chalazal cells during barley grain filling.

PubMed

Asthir, Bavita; Duffus, Carol M; Smith, Rachel C; Spoor, William

2002-04-01

The localization and activities of diamine oxidase (DAO, EC 1.4.3.6) and polyamine oxidase (PAO, EC 1.4.3.4) together with polyamine levels have been investigated in developing grains of barley (Hordeum vulgare L.). DAO (pH 7.5) is present mainly in vascular tissue and its neighbouring cells, namely chalazal cells and nucellar projection, while PAO (pH 6.0) is mainly localized in the chlorenchymatous cells of the crease and at the base of the vascular tissue. Activities of both these enzymes appear to be independently-regulated, as DAO activity increased steadily throughout grain development while PAO activity was higher during the early stages of grain filling, declined thereafter and again increased towards maturity. The maximum activities of DAO coincided with the maximum content of putrescine while the levels of PAO did not seem to be directly correlated with spermidine or spermine contents. Isoelectric focusing (IEF) of DAO and PAO activities revealed the presence of bands at 30 and 45 DPA. The possible involvement of DAO and PAO in the supply of H(2)O(2) to peroxidase-catalysed reactions in the chalazal cells during grain filling is discussed.

Purification of peroxidase from Horseradish (Armoracia rusticana) roots.

PubMed

Lavery, Christopher B; Macinnis, Morgan C; Macdonald, M Jason; Williams, Joanna Bassey; Spencer, Colin A; Burke, Alicia A; Irwin, David J G; D'Cunha, Godwin B

2010-08-11

Peroxidase (EC 1.11.1.7) from horseradish ( Armoracia rusticana ) roots was purified using a simple, rapid, three-step procedure: ultrasonication, ammonium sulfate salt precipitation, and hydrophobic interaction chromatography on phenyl Sepharose CL-4B. The preparation gave an overall yield of 71%, 291-fold purification, and a high specific activity of 772 U mg(-1) protein. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed that the purified enzyme was homogeneous and had a molecular weight of approximately 40 kDa. The isolated enzyme had an isoelectric point of 8.8 and a Reinheitszahl value of 3.39 and was stable when stored in the presence of glycerol at -20 degrees C, with >95% retention of original enzyme activity for at least 6 months. Maximal activity of purified horseradish peroxidase (HRP) was obtained under different optimized conditions: substrate (guaiacol and H(2)O(2)) concentrations (0.5 and 0.3 mM, respectively), type of buffer (50 mM phosphate buffer), pH (7.0), time (1.0 min), and temperature of incubation (30 degrees C). In addition, the effect of HRP and H(2)O(2) in a neutral-buffered aqueous solution for the oxidation of phenol and 2-chlorophenol substrates was also studied. Different conditions including concentrations of phenol/2-chlorophenol, H(2)O(2), and enzyme, time, pH, and temperature were standardized for the maximal activity of HRP with these substrates; under these optimal conditions 89.6 and 91.4% oxidations of phenol and 2-chlorophenol were obtained, respectively. The data generated from this work could have direct implications in studies on the commercial production of this biotechnologically important enzyme and its stability in different media.

Cadmium stress antioxidant responses and root-to-shoot communication in grafted tomato plants.

PubMed

Gratão, Priscila Lupino; Monteiro, Carolina Cristina; Tezotto, Tiago; Carvalho, Rogério Falleiros; Alves, Letícia Rodrigues; Peters, Leila Priscila; Azevedo, Ricardo Antunes

2015-10-01

Many aspects related to ROS modulation of signaling networks and biological processes that control stress responses still remain unanswered. For this purpose, the grafting technique may be a powerful tool to investigate stress signaling and specific responses between plant organs during stress. In order to gain new insights on the modulation of antioxidant stress responses mechanisms, gas-exchange measurements, lipid peroxidation, H2O2 content, proline, superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GR), ascorbate peroxidase (APX) and guaiacol peroxidase (GPOX) were analyzed in Micro-Tom grafted plants submitted to cadmium (Cd). The results observed revealed that higher amounts of Cd accumulated mainly in the roots and rootstocks when compared to leaves and scions. Macronutrients uptake (Ca, S, P and Mg) decreased in non-grafted plants, but differed among plant parts in all grafted plants. The results showed that the accumulation of proline observed in scions of grafted plants could be associated to the lower MDA contents in the scions of grafted plants. In the presence of Cd, non-grafted plants displayed increased CAT, GR, GPOX and APX activities for both tissues, whilst grafted plants revealed distinct trends that clearly indicate signaling responses from the rootstocks, allowing sufficient time to activate defense mechanisms in shoot. The information available concerning plants subjected to grafting can provide a better understanding of the mechanisms of Cd detoxification involving root-to-shoot signaling, opening new possibilities on strategies which can be used to manipulate heavy metal tolerance, since antioxidant systems are directly involved in such mechanism.

Exogenous polyamines elicit herbivore-induced volatiles in lima bean leaves: involvement of calcium, H2O2 and Jasmonic acid.

PubMed

Ozawa, Rika; Bertea, Cinzia M; Foti, Maria; Narayana, Ravishankar; Arimura, Gen-Ichiro; Muroi, Atsushi; Horiuchi, Jun-Ichiro; Nishioka, Takaaki; Maffei, Massimo E; Takabayashi, Junji

2009-12-01

We investigated the role of polyamines (PAs) in lima bean (Phaseolus lunatus) leaves on the production of herbivorous mite (Tetranychus urticae)-induced plant volatiles that attract carnivorous natural enemies of the herbivores. To do this, we focused on the effects of the exogenous PAs [cadaverine, putrescine, spermidine and spermine (Spm)] on the production of volatiles, H(2)O(2) and jasmonic acid (JA) and the levels of defensive genes, cytosolic calcium and reactive oxygen species (ROS). Among the tested PAs, Spm was the most active in inducing the production of volatile terpenoids known to be induced by T. urticae. An increase in JA levels was also found after Spm treatment, indicating that Spm induces the biosynthesis of JA, which has been shown elsewhere to regulate the production of some volatile terpenoids. Further, treatment with JA and Spm together resulted in greater volatile emission than that with JA alone. In a Y-tube olfactometer, leaves treated with Spm + JA attracted more predatory mites (Phytoseiulus persimilis) than those treated with JA alone. After treatment with Spm + JA, no effects were found on the enzyme activity of polyamine oxidase and copper amine oxidase. However, induction of calcium influx and ROS production, and increased enzyme activities and gene expression for NADPH oxidase complex, superoxide dismutase, catalase, ascorbate peroxidase, glutathione reductase and glutathione peroxidase were found after treatment with Spm + JA. These results indicate that Spm plays an important role in the production of T. urticae-induced lima bean leaf volatiles.

Physiological and biochemical responses of Suaeda fruticosa to cadmium and copper stresses: growth, nutrient uptake, antioxidant enzymes, phytochelatin, and glutathione levels.

PubMed

Bankaji, I; Caçador, I; Sleimi, N

2015-09-01

Environmental pollution by trace metal elements (TMEs) is a serious problem worldwide, increasing in parallel with the development of human technology. The present research aimed to examine the response of halophytic species Suaeda fruticosa to oxidative stress posed by combined abiotic stresses. Plants have been grown for 1 month with an irrigation solution supplemented with 200 mM NaCl and 400 μM Cd(2+) or 400 μM Cu(2+). The level of glutathione (GSH), phytochelatins (PCs), and antioxidant enzyme activities [ascorbate peroxidase (APX), guaiacol peroxidase (GPX), and catalase (CAT)] as well as lipid peroxidation was studied to see the stress exerted by the TME and the level of tolerance and detoxification strategy adopted by S. fruticosa. Relative growth rate (RGR) decreased under Cd(2+) stress in this species, whereas Cu(2+) did not have any impact on S. fruticosa performance. Cd(2+) or Cu(2+) enhanced malondialdehyde, suggesting reactive oxygen species-induced disruption of membrane integrity and oxidative stress in S. fruticosa. On the other hand, the activities of the antioxidant enzymes CAT, APX, and GPX diminished and mineral nutrition was disturbed by metal stress. S. fruticosa was able to synthesize PCs in response to TME toxicity. However, data indicate that GSH levels underwent a significant decrease in roots and leaves of S. fruticosa stressed by Cd(2+) or Cu(2+). The GSH depletion accompanied by the increase of phytochelatin concentration suggests the involvement of GSH in the synthesis of phytochelatins.

Scavenging of reactive oxygen species in apoplastic and symplastic areas of rolled leaves in Ctenanthe setosa under drought stress.

PubMed

Saruhan, Neslihan; Terzi, Rabiye; Sağlam, Aykut; Kadioğlu, Asim

2010-09-01

The correspondence among apoplastic and symplastic antioxidant status, stomatal conductance and water potential was investigated during leaf rolling in Ctenanthe setosa (Rosc.) Eichler (Marantaceae) under drought stress. Apoplastic and symplastic extractions of leaf and petiole were performed at different visual leaf rolling scores from 1 to 4 (1 is unrolled, 4 is tightly rolled and the others are intermediate form). In the leaf symplast, the highest changes were found in catalase (CAT) and guaiacol peroxidase (GPX) activities when compared to score 1 during leaf rolling. No significant change was observed in superoxide dismutase (SOD) and ascorbate peroxidase (APX) activities in the symplast of leaf during the rolling. The same phenomenon was also present in the symplast of petiole except APX activity. In the leaf apoplast, the highest increase occurred in APX and GPX activities, whilst a slight increase in CAT and SOD activities. In the apoplast of petiole, the highest increment was found only in GPX activity, while there were small increases in SOD, APX and CAT activities. Hydrogen peroxide content increased up to score 3 in the apoplast and symplast of leaf and petiole but then slightly decreased. Also, superoxide production increased in the leaf and petiole apoplast but its quantity in the apoplast was much more than that of the symplast. On the other hand, NAD(P)H oxidase activity increased in the leaf but no change was observed in the petiole. In conclusion, as a result of water deficit during leaf rolling antioxidant enzymes are induced to scavenging of ROS produced in symplast and apoplast.

Alleviation of salt-induced oxidative damage by 5-aminolevulinic acid in wheat seedlings

NASA Astrophysics Data System (ADS)

Genişel, Mucip; Erdal, Serkan

2016-04-01

The aim of this study was to elucidate how 5-aminolevulinic acid (ALA), the precursor of chlorophyll compounds, affects the defence mechanisms of wheat seedlings induced by salt stress. To determine the possible stimulative effects of ALA against salinity, 11-day old wheat seedlings were sprayed with ALA at two different concentrations (10 and 20 mg.l-1) and then stressed by exposure to salt (150 mM NaCl). The salt stress led to significant changes in the antioxidant activity. While guaiacol peroxidase activity decreased, the activities of superoxide dismutase, catalase, and ascorbate peroxidase markedly increased under salt stress. Compared to the salt stress alone, the application of ALA beforehand further increased the activity of these enzymes. This study is the first time the effects of ALA have been monitored with regard to protein content and the isoenzyme profiles of the antioxidant enzymes. Although the salt stress reduced both the soluble protein content and protein band intensities, pre-treating with ALA significantly mitigated these stress-induced reductions. The data for the isoenzyme profiles of the antioxidant enzymes paralleled that of the ALA-induced increases in antioxidant activity. As a consequence of the high antioxidant activity in the seedlings pre-treated with ALA, the stress-induced elevations in the reactive oxygen species, superoxide anion, and hydrogen peroxide contents and lipid peroxidation levels were markedly diminished. Taken together, this data demonstrated that pre-treating with ALA confers resistance to salt stress by modulating the protein synthesis and antioxidant activity in wheat seedlings.

Investigation of biochemical responses of Bacopa monnieri L. upon exposure to arsenate.

PubMed

Mishra, Seema; Srivastava, Sudhakar; Dwivedi, Sanjay; Tripathi, Rudra Deo

2013-08-01

Widespread contamination of arsenic (As) is recognized as a global problem due to its well-known accumulation by edible and medicinal plants and associated health risks for the humans. In this study, phytotoxicity imposed upon exposure to arsenate [As(V); 0-250 μM for 1-7 days] and ensuing biochemical responses were investigated in a medicinal herb Bacopa monnieri L. vis-à-vis As accumulation. Plants accumulated substantial amount of As (total 768 μg g(-1) dw at 250 μM As(V) after 7 days) with the maximum As retention being in roots (60%) followed by stem (23%) and leaves (17%). The level of cysteine and total nonprotein thiols (NP-SH) increased significantly at all exposure concentrations and durations. Besides, the level of metalloid binding ligands viz., glutathione (GSH) and phytochelatins (PCs) increased significantly at the studied concentrations [50 and 250 μM As(V)] in both roots and leaves. The activities of various enzymes viz., arsenate reductase (AR), glutathione reductase (GR), superoxide dismutase (SOD), guaiacol peroxidase (GPX), ascorbate peroxidase (APX), and catalase (CAT) showed differential but coordinated stimulation in leaves and roots to help plants combat As toxicity up to moderate exposure concentrations (50 μM). However, beyond 50 μM, biomass production was found to decrease along with photosynthetic pigments and total soluble proteins, whereas lipid peroxidation increased. In conclusion, As accumulation potential of Bacopa may warrant its use as a phytoremediator but if Bacopa growing in contaminated areas is consumed by humans, it may prove to be toxic for health. Copyright © 2011 Wiley Periodicals, Inc.

Toxicological effects, mechanisms, and implied toxicity thresholds in the roots of Vicia faba L. seedlings grown in copper-contaminated soil.

PubMed

Xu, Xianghua; Huang, Zhicheng; Wang, Chengrun; Zhong, Li; Tian, Yuan; Li, Dongdong; Zhang, Gaojian; Shi, Jian

2015-09-01

Copper (Cu) contamination has become a global concern because of industrial, agricultural, and other anthropogenic activities. In the present experiments, the toxicological effects, mechanisms, and potential toxicity thresholds were investigated in the roots of Vicia faba L. seedlings that were cultivated in Cu-amended soils (0, 6.25, 12.5, 25, 50, 100, 200, 400, and 600 mg kg(-1)) for 20 days, based on an analysis of the soil physicochemical properties, native Cu, available Cu, and root-enriched Cu contents. The superoxide dismutase (SOD), ascorbate peroxidase (APX), and guaiacol peroxidase (POD) isozymes and activities, as well as glutathione (GSH) and heat shock protein 70 (HSP70), changed like biphasic dose-response curves, cooperating to control the redox homeostasis. The APX and POD enzymes exhibited enhanced activities and became H2O2 scavengers primarily when the catalase (CAT) activities tended to decrease. Endoprotease (EP) isozymes and activities might be enhanced to degrade carbonylated proteins and alleviate metabolic disturbance in the roots. Additionally, HSP70 may not be suitable as a biomarker for relatively higher soil Cu concentrations and relatively longer exposure times for the roots. As a result, the isozymes and activities of SOD, CAT, and EP, as well as GSH, can be adopted as the most sensitive biomarkers. The toxicity threshold is estimated as 0.76-1.21 mg kg(-1) of available Cu in the soils or 25.04-36.65 μg Cu g(-1) dry weights (DW) in the roots.

Application of Exogenous Ethylene Inhibits Postharvest Peel Browning of 'Huangguan' Pear.

PubMed

Ma, Yurong; Yang, Mengnan; Wang, Jingjing; Jiang, Cai-Zhong; Wang, Qingguo

2016-01-01

Peel browning disorder has an enormous impact on the exterior quality of 'Huangguan' pear whereas the underlying mechanism is still unclear. Although different methods have been applied for inhibiting the peel browning of 'Huangguan' pear, there are numerous issues associated with these approaches, such as time cost, efficacy, safety and stability. In this study, to develop a rapid, efficient and safe way to protect 'Huangguan' pear from skin browning, the effect of exogenous ethylene on peel browning of pear fruits stored at 0°C was evaluated. Results showed that ethylene treatments at 0.70-1.28 μL/L significantly decreased the browning rate and browning index from 73.80% and 0.30 to 6.80% and 0.02 after 20 days storage at 0°C, respectively, whereas ethylene treatments at 5 μL/L completely inhibited the occurrence of browning. In addition, ethylene treatments at 5 μL/L decreased the electrolyte leakage and respiration rate, delayed the loss of total phenolic compounds. Furthermore, ethylene (5 μL/L) treatment significantly enhanced the activity of catalase (CAT), ascorbate peroxidase (APX) and superoxide dismutase (SOD) and increased the 1, 1-diphenyl-2-picrylhydrazyl inhibition rate, but inhibited the activity of polyphenol oxidase (PPO) and peroxidase (POD). Our data revealed that ethylene prevented the peel browning through improving antioxidant enzymes (CAT, APX and SOD) activities and reducing PPO activity, electrolyte leakage rate and respiration rate. This study demonstrates that exogenous ethylene application may provide a safe and effective alternative method for controlling browning, and contributes to the understanding of peel browning of 'Huangguan' pear.

Differential coral bleaching-Contrasting the activity and response of enzymatic antioxidants in symbiotic partners under thermal stress.

PubMed

Krueger, Thomas; Hawkins, Thomas D; Becker, Susanne; Pontasch, Stefanie; Dove, Sophie; Hoegh-Guldberg, Ove; Leggat, William; Fisher, Paul L; Davy, Simon K

2015-12-01

Mass coral bleaching due to thermal stress represents a major threat to the integrity and functioning of coral reefs. Thermal thresholds vary, however, between corals, partly as a result of the specific type of endosymbiotic dinoflagellate (Symbiodinium sp.) they harbour. The production of reactive oxygen species (ROS) in corals under thermal and light stress has been recognised as one mechanism that can lead to cellular damage and the loss of their symbiont population (Oxidative Theory of Coral Bleaching). Here, we compared the response of symbiont and host enzymatic antioxidants in the coral species Acropora millepora and Montipora digitata at 28°C and 33°C. A. millepora at 33°C showed a decrease in photochemical efficiency of photosystem II (PSII) and increase in maximum midday excitation pressure on PSII, with subsequent bleaching (declining photosynthetic pigment and symbiont density). M. digitata exhibited no bleaching response and photochemical changes in its symbionts were minor. The symbiont antioxidant enzymes superoxide dismutase, ascorbate peroxidase, and catalase peroxidase showed no significant upregulation to elevated temperatures in either coral, while only catalase was significantly elevated in both coral hosts at 33°C. Increased host catalase activity in the susceptible coral after 5days at 33°C was independent of antioxidant responses in the symbiont and preceded significant declines in PSII photochemical efficiencies. This finding suggests a potential decoupling of host redox mechanisms from symbiont photophysiology and raises questions about the importance of symbiont-derived ROS in initiating coral bleaching. Copyright © 2015 Elsevier Inc. All rights reserved.

Molecular cloning and in-silico characterization of high temperature stress responsive pAPX gene isolated from heat tolerant Indian wheat cv. Raj 3765.

PubMed

Padaria, Jasdeep Chatrath; Vishwakarma, Harinder; Biswas, Koushik; Jasrotia, Rahul Singh; Singh, Gyanendra Pratap

2014-10-10

Heat stress leads to accelerated production of reactive oxygen species (ROS) which causes a huge amount of oxidative damage to the cellular components of plants. A large number of heat stress related genes as HSPs, catalases, peroxidases are overexpressed at the time of stress. A potent stress responsive gene peroxisomal ascorbate peroxidase (TapAPX) obtained from heat stress (42 °C) responsive subtractive cDNA library from a thermo tolerant wheat cv. Raj3765 at anthesis stage was cloned, characterized and its role was validated under heat stress by proteomics and in-silico studies. In the present study we report the characterization at molecular and in-silico level of peroxisomal TapAPX gene isolated from heat tolerant wheat cultivar of India. qPCR studies of TapAPX gene displayed up to 203 fold level of expression at 42 °C heat stress exposure. A full length cDNA of 876 bp obtained by RACE deduced a protein of 292 amino acid residues which gives a complete 3D structure of pAPX by homology modeling. TapAPX cDNA was cloned in expression vector pET28 (a+) and the recombinant protein over-expressed in E. coli BL21 showed highest homology with APX protein as deduced by peptide mass fingerprinting. TapAPX gene from wheat cv Raj3765 has a distinct role in conferring thermo tolerance to the plants and thus can be used in crop improvement programmes for development of crops tolerant to high temperature.

Silicon nanoparticles more effectively alleviated UV-B stress than silicon in wheat (Triticum aestivum) seedlings.

PubMed

Tripathi, Durgesh Kumar; Singh, Swati; Singh, Vijay Pratap; Prasad, Sheo Mohan; Dubey, Nawal Kishore; Chauhan, Devendra Kumar

2017-01-01

The role of silicon (Si) in alleviating biotic as well as abiotic stresses is well known. However, the potential of silicon nanoparticle (SiNP) in regulating abiotic stress and associated mechanisms have not yet been explored. Therefore, in the present study hydroponic experiments were conducted to investigate whether Si or SiNp are more effective in the regulation of UV-B stress. UV-B (ambient and enhanced) radiation caused adverse effect on growth of wheat (Triticum aestivum) seedlings, which was accompanied by declined photosynthetic performance and altered vital leaf structures. Levels of superoxide radical and H 2 O 2 were enhanced by UV-B as also evident from their histochemical stainings, which was accompanied by increased lipid peroxidation (LPO) and electrolyte leakage. Activities of superoxide dismutase and ascorbate peroxidase were inhibited by UV-B while catalase and guaiacol peroxidase, and all non-enzymatic antioxidants were stimulated by UV-B. Although, nitric oxide (NO) content was increased at all tested combinations, but its maximum content was observed under SiNps together with UV-B enhanced treatment. Pre-additions of SiNp as well as Si protected wheat seedlings against UV-B by regulating oxidative stress through enhanced antioxidants. Data indicate that SiNp might have protected wheat seedlings through NO-mediated triggering of antioxidant defense system, which subsequently counterbalance reactive oxygen species-induced damage to photosynthesis. Further, SiNp appear to be more effective in reducing UV-B stress than Si, which is related to its greater availability to wheat seedlings. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Methane alleviates copper-induced seed germination inhibition and oxidative stress in Medicago sativa.

PubMed

Samma, Muhammad Kaleem; Zhou, Heng; Cui, Weiti; Zhu, Kaikai; Zhang, Jing; Shen, Wenbiao

2017-02-01

Recent results discovered the protective roles of methane (CH 4 ) against oxidative stress in animals. However, the possible physiological roles of CH 4 in plants are still unknown. By using physiological, histochemical and molecular approaches, the beneficial role of CH 4 in germinating alfalfa seeds upon copper (Cu) stress was evaluated. Endogenous production of CH 4 was significantly increased in Cu-stressed alfalfa seeds, which was mimicked by 0.39 mM CH 4 . The pretreatment with CH 4 significantly alleviated the inhibition of seed germination and seedling growth induced by Cu stress. Cu accumulation was obviously blocked as well. Meanwhile, α/β amylase activities and sugar contents were increased, all of which were consistent with the alleviation of seed germination inhibition triggered by CH 4 . The Cu-triggered oxidative stress was also mitigated, which was confirmed by the decrease of lipid peroxidation and reduction of Cu-induced loss of plasma membrane integrity in CH 4 -pretreated alfalfa seedlings. The results of antioxidant enzymes, including ascorbate peroxidase (APX), superoxide dismutase (SOD), catalase (CAT), and guaiacol peroxidase (POD) total or isozymatic activities, and corresponding transcripts (APX1/2, Cu/Zn SOD and Mn-SOD), indicated that CH 4 reestablished cellular redox homeostasis. Further, Cu-induced proline accumulation was partly impaired by CH 4 , which was supported by the alternation of proline metabolism. Together, these results indicated that CH 4 performs an advantageous effect on the alleviation of seed germination inhibition caused by Cu stress, and reestablishment of redox homeostasis mainly via increasing antioxidant defence.

Vesicular transport route of horseradish C1a peroxidase is regulated by N- and C-terminal propeptides in tobacco cells.

PubMed

Matsui, T; Nakayama, H; Yoshida, K; Shinmyo, A

2003-10-01

Peroxidases (PRX, EC 1.11.1.7) are widely distributed across microorganisms, plants, and animals; and, in plants, they have been implicated in a variety of secondary metabolic reactions. In particular, horseradish (Armoracia rusticana) root represents the main source of commercial PRX production. The prxC1a gene, which encodes horseradish PRX (HRP) C, is expressed mainly in the roots and stems of the horseradish plant. HRP C1a protein is shown to be synthesized as a preprotein with both a N-terminal (NTPP) and a C-terminal propeptide (CTPP). These propeptides, which might be responsible for intracellular localization or secretion, are removed before or concomitant with production of the mature protein. We investigated the functional role of HRP C1a NTPP and CTPP in the determination of the vesicular transport route, using an analytical system of transgenically cultured tobacco cells (Nicotiana tabacum, BY2). Here, we report that NTPP and CTPP are necessary and sufficient for accurate localization of mature HRP C1a protein to vacuoles of the vesicular transport system. We also demonstrate that HRP C1a derived from a preprotein lacking CTPP is shunted into the secretory pathway.

Proteomics approach combined with biochemical attributes to elucidate compatible and incompatible plant-virus interactions between Vigna mungo and Mungbean Yellow Mosaic India Virus.

PubMed

Kundu, Subrata; Chakraborty, Dipjyoti; Kundu, Anirban; Pal, Amita

2013-01-01

Vigna mungo, a tropical leguminous plant, highly susceptible to yellow mosaic disease caused by Mungbean Yellow Mosaic India Virus (MYMIV) resulting in high yield penalty. The molecular events occurring during compatible and incompatible interactions between V. mungo and MYMIV pathosystem are yet to be explored. In this study biochemical analyses in conjunction with proteomics of MYMIV-susceptible and -resistant V. mungo genotypes were executed to get an insight in the molecular events during compatible and incompatible plant-virus interactions. Biochemical analysis revealed an increase in phenolics, hydrogen peroxide and carbohydrate contents in both compatible and incompatible interactions; but the magnitudes were higher during incompatible interaction. In the resistant genotype the activities of superoxide dismutase and ascorbate peroxidase increased significantly, while catalase activity decreased. Comparative proteome analyses using two-dimensional gel electrophoresis coupled with mass spectrometry identified 109 differentially abundant proteins at 3, 7 and 14 days post MYMIV-inoculation. Proteins of several functional categories were differentially changed in abundance during both compatible and incompatible interactions. Among these, photosynthesis related proteins were mostly affected in the susceptible genotype resulting in reduced photosynthesis rate under MYMIV-stress. Differential intensities of chlorophyll fluorescence and chlorophyll contents are in congruence with proteomics data. It was revealed that Photosystem II electron transports are the primary targets of MYMIV during pathogenesis. Quantitative real time PCR analyses of selected genes corroborates with respective protein abundance during incompatible interaction. The network of various cellular pathways that are involved in inducing defense response contains several conglomerated cores of nodal proteins, of which ascorbate peroxidase, rubisco activase and serine/glycine hydroxymethyl transferase are the three major hubs with high connectivity. These nodal proteins play the crucial role of key regulators in bringing about a coordinated defense response in highly orchestrated manner. Biochemical and proteomic analyses revealed early accumulation of the defense/stress related proteins involved in ROS metabolism during incompatible interaction. The robustness in induction of defense/stress and signal transduction related proteins is the key factor in inducing resistance. The mechanism of MYMIV-resistance in V. mungo involves redirection of carbohydrate flux towards pentose phosphate pathway. Some of these identified, differentially regulated proteins are also conferring abiotic stress responses illustrating harmony amongst different stress responses. To the best of our knowledge, this is the lone study deciphering differential regulations of V. mungo leaf proteome upon MYMIV infection elucidating the mode of resistance response at the biochemical level.

Biochemical and physiological responses of oil palm to bud rot caused by Phytophthora palmivora.

PubMed

Moreno-Chacón, Andrés Leonardo; Camperos-Reyes, Jhonatan Eduardo; Ávila Diazgranados, Rodrigo Andrés; Romero, Hernán Mauricio

2013-09-01

In recent years, global consumption of palm oil has increased significantly, reaching almost 43 million tons in 2010. The sustainability of oil palm (Elaeis guineensis) cultivation has been compromised because of the bud rot disease whose initial symptoms are caused by Phytophthora palmivora. There was a significant incidence of the disease, from an initial stage 1 of the disease to the highest stage 5, that affected photosynthetic parameters, content of pigments, sugars, polyamines, enzymatic antioxidant activities, phenylalanine ammonia-lyase (PAL, EC 4.3.1.5) and β-(1,3) glucanase (β-Gluc, EC 3.2.1.39). In healthy palms photosynthesis was 13.29 μmol CO2 m(-2) s(-1) in average, while in stage 5 the average photosynthesis was around 3.66 μmol CO2 m(-2) s(-1). Additionally, total chlorophyll was reduced by half at the last stage of the disease. On the contrary, the contents of putrescine, spermine and spermidine increased three, nine and twelve times with respect to stage 5, respectively. Antioxidant enzyme activities, as well as the phenylalanine ammonia-lyase and β-(1,3) glucanase showed an increase as the severity of the disease increased, with the latter increasing from 0.71 EAU in healthy palms to 2.60 EAU in plants at stage 5 of the disease. The peroxidase (POD, EC 1.11.1.7) enzymatic activity and the content of spermidine were the most sensitive indicators of disease. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

The combination of arbuscular mycorrhizal fungi inoculation (Glomus versiforme) and 28-homobrassinolide spraying intervals improves growth by enhancing photosynthesis, nutrient absorption, and antioxidant system in cucumber (Cucumis sativus L.) under salinity.

PubMed

Ahmad, Husain; Hayat, Sikandar; Ali, Muhammad; Liu, Tao; Cheng, Zhihui

2018-06-01

Salinity is one of the major obstacles in the agriculture industry causing huge losses in productivity. Several strategies such as plant growth regulators with arbuscular mycorrhizal fungi (AMF) have been used to decrease the negative effects of salt stress. In our experiment, 28-homobrassinolide (HBL) with spraying intervals was combined with AMF ( Glomus versiforme ) in cucumber cultivars Jinyou 1 # (salt sensitive) and (Changchun mici, in short, CCMC, salt tolerant) under NaCl (100 mmol/L). Studies have documented that the foliar application of HBL and AMF colonization can enhance tolerance to plants under stress conditions. However, the mechanism of the HBL spraying intervals after 15 and 30 days in combination with AMF in cucumber under salt stress is still unknown. Our results revealed that the HBL spraying interval after 15 days in combination with AMF resulted in improved growth, photosynthesis, and decreased sodium toxicity under NaCl. Moreover, the antioxidant enzymes SOD (superoxide dismutase; EC 1.15.1.1) and POD activity (peroxidase; EC 1.11.1.7) showed a gradual increase after every 10 days, while the CAT (catalase; EC 1.11.1.6) increased after 30 days of salt treatments in both cultivars. This research suggests that the enhanced tolerance to salinity was mainly related to elevated levels of antioxidant enzymes and lower uptake of Na + , which lowers the risk of ion toxicity and decreases cell membrane damage.

Biochemical changes in grape rootstocks resulted from humic acid treatments in relation to nematode infection.

PubMed

Kesba, Hosny H; El-Beltagi, Hossam S

2012-04-01

To investigate the effect of humic acid on nematode infected, resistant and susceptible grapes in relation to lipid peroxidation and antioxidant mechanisms on selected biochemical parameters known as proactive substances. The grape rootstocks, superior, superior/freedom and freedom were reacted differently to Meloidogyne incognita and Rotylenchulus reniformis according to rootstock progenitor. Two weeks after inoculation, two commercial products of humic acid were applied at the rate of (2, 4 mL or grams/plant) as soil drench. After 4 months, nematode soil populations were extracted and counted. A subsample of roots from each plant was stained and gall numbers, embedded stages per root were calculated, final population, nematode build up (Pf/Pi), average of eggs/eggmass were estimated. Subsamples of fresh root of each treatment were chemically analyzed. Freedom reduced significantly the nematode criteria and build up. Humic acid granules appeared to be more suppressive to nematode build up on superior and the higher dose on superior/freedom than liquid treatments. On freedom, all treatments reduced significantly the nematode build up regardless to the material nature. The higher dose was more effective than the lower one. As a result of humic acid applications, the malondialdehyde (MDA) and H2O2 contents were significantly reduced after humic acid treatments while the antioxidant compounds glutathione (GSH), ascorbic acid (ASA) and total phenol contents were significantly increased when compared with check. Antioxidant defense enzymes ascorbate peroxidase (APX), superoxide dismutase (SOD), catalase (CAT) and polyphenol oxidase (PPO)showed significant increase in their specific activities in treated plants compared with nematode treated check. Humic acid treatments improve the yield of grape by increasing the contents of antioxidant compounds and the specific activities of antioxidant enzymes.

Excess boron responsive regulations of antioxidative mechanism at physio-biochemical and molecular levels in Arabidopsis thaliana.

PubMed

Kayıhan, Doğa Selin; Kayıhan, Ceyhun; Çiftçi, Yelda Özden

2016-12-01

This work was aimed to evaluate the effect of boron (B) toxicity on oxidative damage level, non-enzymatic antioxidant accumulation such as anthocyanin, flavonoid and proline and expression levels of antioxidant enzymes including superoxide dismutase (SOD), ascorbate peroxidase (APX), catalase (CAT) and glutathione reductase (GR) and their respective activities as well as expression levels of miR398 and miR408 in Arabidopsis thaliana. Plants were germinated and grown on MS medium containing 1 mM B (1B) and 3 mM B (3B) for 14 d. Toxic B led to a decrease of photosynthetic pigments and an increase in accumulation of total soluble and insoluble sugars in accordance with phenotypically viewed chlorosis of seedlings through increasing level of B concentration. Along with these inhibitions, a corresponding increase in contents of flavonoid, anthocyanin and proline occurred that provoked oxidative stress tolerance. 3B caused a remarkable increase in total SOD activity whereas the activities of APX, GR and CAT remained unchanged as verified by expected increase in H 2 O 2 content. In contrast to GR, the coincidence was found between the expressions of SOD and APX genes and their respective activities. 1B induced mir398 expression, whereas 3B did not cause any significant change in expression of mir408 and mir398. Expression levels of GR genes were coordinately regulated with DHAR2 expression. Moreover, the changes in expression level of MDAR2 was in accordance with changes in APX6 expression and total APX activity, indicating fine-tuned regulation of ascorbate-glutathione cycle which might trigger antioxidative responses against B toxicity in Arabidopsis thaliana. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Cumulative effect of nitrogen and sulphur on Brassica juncea L. genotypes under NaCl stress.

PubMed

Siddiqui, Manzer H; Mohammad, Firoz; Khan, M Masrooor A; Al-Whaibi, Mohamed H

2012-01-01

In the present study, N and S assimilation, antioxidant enzymes activity, and yield were studied in N and S-treated plants of Brassica juncea (L.) Czern. & Coss. (cvs. Chuutki and Radha) under salt stress. The treatments were given as follows: (1) NaCl(90) mM+N(0)S(0) mg kg(-1) sand (control), (2) NaCl(90) mM+N(60)S(0) mg kg(-1) sand, (3) NaCl(90) mM+N(60)S(20) mg kg(-1) sand, (4) NaCl(90) mM+N(60)S(40) mg kg(-1) sand, and (5) NaCl(90) mM+N(60)S(60) mg kg(-1) sand. The combined application of N (60 mg kg(-1) sand) and S (40 mg kg(-1) sand) proved beneficial in alleviating the adverse effect of salt stress on growth attributes (shoot length plant(-1), fresh weight plant(-1), dry weight plant(-1), and area leaf(-1)), physio-biochemical parameters (carbonic anhydrase activity, total chlorophyll, adenosine triphosphate-sulphurylase activity, leaf N, K and Na content, K/Na ratio, activity of nitrate reductase, nitrite reductase, glutamine synthetase, glutamate synthase, catalase, superoxide dismutase, ascorbate peroxidase and glutathione reductase, and content of glutathione and ascorbate), and yield attributes (pods plant(-1), seeds pod(-1), and seed yield plant(-1)). Therefore, it is concluded that combined application of N and S induced the physiological and biochemical mechanisms of Brassica. The stimulation of antioxidant enzymes activity and its synergy with N and S assimilation may be one of the important mechanisms that help the plants to tolerate the salinity stress and resulted in an improved yield.

Tetraploid Carrizo citrange rootstock (Citrus sinensis Osb.×Poncirus trifoliata L. Raf.) enhances natural chilling stress tolerance of common clementine (Citrus clementina Hort. ex Tan).

PubMed

Oustric, Julie; Morillon, Raphaël; Luro, François; Herbette, Stéphane; Lourkisti, Radia; Giannettini, Jean; Berti, Liliane; Santini, Jérémie

2017-07-01

Low temperatures can disturb the development, growth and geographic distribution of plants, particularly cold-sensitive plants in the Mediterranean area, where temperatures can reach seasonally low levels. In citrus crops, scion/rootstock combinations are used to improve fruit production and quality, and increase tolerance to biotic and abiotic stresses. In the last decade, several studies have shown that tetraploid citrus seedlings or rootstocks are more tolerant to abiotic stress than their respective diploid. The objective of this study was to test whether the use of tetraploid rootstocks can improve the chilling tolerance of the scion. We compared physiological and biochemical responses to low seasonal temperatures of common Clementine (Citrus sinensis Osb.×Poncirus trifoliata L. Raf.) grafted on diploid and tetraploid Carrizo citrange rootstocks, named C/2xCC and C/4xCC, respectively. During the coldest months, C/4xCC showed a smaller decrease in net photosynthesis (Pn), stomatal conductance (G s ), chlorophyll fluorescence (F v /F m ), and starch levels, and lower levels of malondialdehyde and electrolyte leakage than C/2xCC. Specific activities of catalase (CAT), ascorbate peroxidase (APX) and dehydroascorbate reductase (DHAR) were higher in C/4xCC during the cold period, whereas chlorophyll, proline, ascorbate and hydrogen peroxide (H 2 O 2 ) levels and superoxide dismutase (SOD) activity did not vary significantly between C/4xCC and C/2xCC throughout the study period. Taken together, these results demonstrate that tetraploid Carrizo citrange rootstock improves the chilling tolerance of common clementine (scion) thanks to a part of the antioxidant system. Copyright © 2017. Published by Elsevier GmbH.

Haem oxygenase delays programmed cell death in wheat aleurone layers by modulation of hydrogen peroxide metabolism

PubMed Central

Wu, Mingzhu; Huang, Jingjing; Xu, Sheng; Ling, Tengfang; Xie, Yanjie; Shen, Wenbiao

2011-01-01

Haem oxygenase-1 (HO-1) confers protection against a variety of oxidant-induced cell and tissue injury in animals and plants. In this report, it is confirmed that programmed cell death (PCD) in wheat aleurone layers is stimulated by GA and prevented by ABA. Meanwhile, HO activity and HO-1 protein expression exhibited lower levels in GA-treated layers, whereas the hydrogen peroxide (H2O2) content was apparently increased. The pharmacology approach illustrated that scavenging or accumulating H2O2 either delayed or accelerated GA-induced PCD. Furthermore, pretreatment with the HO-1 specific inhibitor, zinc protoporphyrin IX (ZnPPIX), before exposure to GA, not only decreased HO activity but also accelerated GA-induced PCD significantly. The application of the HO-1 inducer, haematin, and the enzymatic reaction product of HO, carbon monoxide (CO) aqueous solution, both of which brought about a noticeable induction of HO expression, substantially prevented GA-induced PCD. These effects were reversed when ZnPPIX was added, suggesting that HO in vivo played a role in delaying PCD. Meanwhile, catalase (CAT) and ascorbate peroxidase (APX) activities or transcripts were enhanced by haematin, CO, or bilirubin (BR), the catalytic by-product of HO. This enhancement resulted in a decrease in H2O2 production and a delay in PCD. In addition, the antioxidants butylated hydroxytoluene (BHT), dithiothreitol (DTT), and ascorbic acid (AsA) were able not only to delay PCD but also to mimic the effects of haematin and CO on HO up-regulation. Overall, the above results suggested that up-regulation of HO expression delays PCD through the down-regulation of H2O2 production. PMID:20797999

Pb-induced responses in Zygophyllum fabago plants are organ-dependent and modulated by salicylic acid.

PubMed

López-Orenes, Antonio; Martínez-Pérez, Ascensión; Calderón, Antonio A; Ferrer, María A

2014-11-01

Zygophyllum fabago is a promising species for restoring heavy metal (HM) polluted soils, although the mechanisms involved in HM tolerance in this non-model plant remain largely unknown. This paper analyses the extent to which redox-active compounds and enzymatic antioxidants in roots, stems and leaves are responsible for Pb tolerance in a metallicolous ecotype of Z. fabago and the possible influence of salicylic acid (SA) pretreatment (24 h, 0.5 mM SA) in the response to Pb stress. SA pretreatment reduced both the accumulation of Pb in roots and even more so the concentration of Pb in aerial parts of the plants, although a similar drop in the content of chlorophylls and in the maximum quantum yield of photosystem II was observed in both Pb- and SA-Pb-treated plants. Pb increased the endogenous free SA levels in all organs and this response was enhanced in root tissues upon SA pretreatment. Generally, Pb induced a reduction in catalase, ascorbate peroxidase and glutathione reductase specific activities, whereas dehydroascorbate reductase was increased in all organs of control plants. SA pretreatment enhanced the Pb-induced H2O2 accumulation in roots by up-regulating Fe-superoxide dismutase isoenzymes. Under Pb stress, the GSH redox ratio remained highly reduced in all organs while the ascorbic acid redox ratio dropped in leaf tissues where a rise in lipid peroxidation products and electrolyte leakage was observed. Finally, an organ-dependent accumulation of proline and β-carboline alkaloids was found, suggesting these nitrogen-redox-active compounds could play a role in the adaptation strategies of this species to Pb stress. Copyright © 2014. Published by Elsevier Masson SAS.

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

PubMed

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.

Modulation of redox regulatory molecules and electron transport chain activity in muscle of air breathing fish Heteropneustes fossilis under air exposure stress.

PubMed

Paital, Biswaranjan

2014-01-01

Responses of redox regulatory system to long-term survival (>18 h) of the catfish Heteropneustes fossilis in air are not yet understood. Lipid and protein oxidation level, oxidant (H2O2) generation, antioxidative status (levels of superoxide dismutase, catalase, glutathione peroxidase and reductase, ascorbic acid and non-protein sulfhydryl) and activities of respiratory complexes (I, II, III and IV) in mitochondria were investigated in muscle of H. fossilis under air exposure condition (0, 3, 6, 12 and 18 h at 25 °C). The increased levels of both H2O2 and tissue oxidation were observed due to the decreased activities of antioxidant enzymes in muscle under water deprivation condition. However, ascorbic acid and non-protein thiol groups were the highest at 18 h air exposure time. A linear increase in complex II activity with air exposure time and an increase up to 12 h followed by a decrease in activity of complex I at 18 h were observed. Negative correlation was observed for complex III and V activity with exposure time. Critical time to modulate the above parameters was found to be 3 h air exposure. Dehydration induced oxidative stress due to modulation of electron transport chain and redox metabolizing enzymes in muscle of H. fossilis was clearly observed. Possible contribution of redox regulatory system in muscle tissue of the fish for long-term survival in air is elucidated. Results of the present study may be useful to understand the redox metabolism in muscle of fishes those are exposed to air in general and air breathing fishes in particular.

Copper-induced overexpression of genes encoding antioxidant system enzymes and metallothioneins involve the activation of CaMs, CDPKs and MEK1/2 in the marine alga Ulva compressa.

PubMed

Laporte, Daniel; Valdés, Natalia; González, Alberto; Sáez, Claudio A; Zúñiga, Antonio; Navarrete, Axel; Meneses, Claudio; Moenne, Alejandra

2016-08-01

Transcriptomic analyses were performed in the green macroalga Ulva compressa cultivated with 10μM copper for 24h. Nucleotide sequences encoding antioxidant enzymes, ascorbate peroxidase (ap), dehydroascorbate reductase (dhar) and glutathione reductase (gr), enzymes involved in ascorbate (ASC) synthesis l-galactose dehydrogenase (l-gdh) and l-galactono lactone dehydrogenase (l-gldh), in glutathione (GSH) synthesis, γ-glutamate-cysteine ligase (γ-gcl) and glutathione synthase (gs), and metal-chelating proteins metallothioneins (mt) were identified. Amino acid sequences encoded by transcripts identified in U. compressa corresponding to antioxidant system enzymes showed homology mainly to plant and green alga enzymes but those corresponding to MTs displayed homology to animal and plant MTs. Level of transcripts encoding the latter proteins were quantified in the alga cultivated with 10μM copper for 0-12 days. Transcripts encoding enzymes of the antioxidant system increased with maximal levels at day 7, 9 or 12, and for MTs at day 3, 7 or 12. In addition, the involvement of calmodulins (CaMs), calcium-dependent protein kinases (CDPKs), and the mitogen-activated protein kinase kinase (MEK1/2) in the increase of the level of the latter transcripts was analyzed using inhibitors. Transcript levels decreased with inhibitors of CaMs, CDPKs and MEK1/2. Thus, copper induces overexpression of genes encoding antioxidant enzymes, enzymes involved in ASC and GSH syntheses and MTs. The increase in transcript levels may involve the activation of CaMs, CDPKs and MEK1/2 in U. compressa. Copyright © 2016 Elsevier B.V. All rights reserved.

Exogenous NO depletes Cd-induced toxicity by eliminating oxidative damage, re-establishing ATPase activity, and maintaining stress-related hormone equilibrium in white clover plants.

PubMed

Liu, S L; Yang, R J; Pan, Y Z; Wang, M H; Zhao, Y; Wu, M X; Hu, J; Zhang, L L; Ma, M D

2015-11-01

Various nitric oxide (NO) regulators [including the NO donor sodium nitroprusside (SNP), the NO scavenger 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (cPTIO), the NO-synthase inhibitor N (G)-nitro-L-Arg-methyl ester (L-NAME), and the SNP analogues sodium nitrite/nitrate and sodium ferrocyanide] were investigated to elucidate the role of NO in white clover (Trifolium repens L.) plants after long-term (5 days) exposure to cadmium (Cd). A dose of 100 μM Cd stress significantly restrained plant growth and decreased the concentrations of chlorophyll and NO in vivo, whereas it disrupted the balance of stress-related hormones and enhanced the accumulation of Cd, thereby inducing reactive oxygen species (ROS) burst. However, the inhibition of plant growth was relieved by 50 μM SNP through its stimulation of ROS-scavenging compounds (ascorbic acid, ascorbate peroxidase, catalase, glutathione reductase, non-protein thiol, superoxide dismutase, and total glutathione), regulation of H(+)-ATPase activity of proton pumps, and increasing jasmonic acid and proline but decreasing ethylene in plant tissues. Even so, the alleviating effect of SNP on plant growth was counteracted by cPTIO and L-NAME and was not observed with SNP analogues, suggesting that the protective roles of SNP are related to the induction of NO. These results suggest that NO may improve the Cd tolerance of white clover plants by eliminating oxidative damage, re-establishing ATPase activity, and maintaining hormone equilibrium. Improving our understanding of the role of NO in white clover plants is key to expanding the plantations to various regions and the recovery of pasture species in the future.

Biochemical changes in grape rootstocks resulted from humic acid treatments in relation to nematode infection

PubMed Central

Kesba, Hosny H; El-Beltagi, Hossam S

2012-01-01

Objective To investigate the effect of humic acid on nematode infected, resistant and susceptible grapes in relation to lipid peroxidation and antioxidant mechanisms on selected biochemical parameters known as proactive substances. Methods The grape rootstocks, superior, superior/freedom and freedom were reacted differently to Meloidogyne incognita and Rotylenchulus reniformis according to rootstock progenitor. Two weeks after inoculation, two commercial products of humic acid were applied at the rate of (2, 4 mL or grams/plant) as soil drench. After 4 months, nematode soil populations were extracted and counted. A subsample of roots from each plant was stained and gall numbers, embedded stages per root were calculated, final population, nematode build up (Pf/Pi), average of eggs/eggmass were estimated. Subsamples of fresh root of each treatment were chemically analyzed. Results Freedom reduced significantly the nematode criteria and build up. Humic acid granules appeared to be more suppressive to nematode build up on superior and the higher dose on superior/freedom than liquid treatments. On freedom, all treatments reduced significantly the nematode build up regardless to the material nature. The higher dose was more effective than the lower one. As a result of humic acid applications, the malondialdehyde (MDA) and H2O2 contents were significantly reduced after humic acid treatments while the antioxidant compounds glutathione (GSH), ascorbic acid (ASA) and total phenol contents were significantly increased when compared with check. Antioxidant defense enzymes ascorbate peroxidase (APX), superoxide dismutase (SOD), catalase (CAT) and polyphenol oxidase (PPO)showed significant increase in their specific activities in treated plants compared with nematode treated check. Conclusions Humic acid treatments improve the yield of grape by increasing the contents of antioxidant compounds and the specific activities of antioxidant enzymes. PMID:23569915

High prevalence of ascorbate deficiency in an Australian peritoneal dialysis population.

PubMed

Singer, Richard; Rhodes, Helen C; Chin, George; Kulkarni, Hemant; Ferrari, Paolo

2008-02-01

An adequate total body pool of ascorbate is essential for optimum health in humans. Requirements for ascorbate are increased in peritoneal dialysis (PD) patients most likely due to a combination of poor nutrition and increased dialysate losses. We measured serum ascorbate levels in 45 clinically stable PD patients to assess the prevalence of ascorbate insufficiency (level between 2 and 4 mg/L) and deficiency (level <2 mg/L). We also assessed the efficacy of subsequent supplementation and patients' adherence to the prescribed supplementation. All patients were advised on commencement of dialysis to take a multivitamin tablet containing 100-120 mg ascorbate. Eighteen (41%) PD patients were regularly taking ascorbate-containing multivitamins, while 27 (59%) patients did not take ascorbate supplements. Serum ascorbate levels ranged from <0.2 to 41 mg/L, with wide variations in serum ascorbate at any given intake level. Ascorbate deficiency was present in 1/3 of the current PD population (44% of patients not taking supplements and in 16% of those on supplements), although none of the patients demonstrated clinical manifestations of scurvy. Targeted supplementation of ascorbate insufficient patients increased the median serum ascorbate level from 1.7 mg/L (IQR 1.2-2.2) to 22.5 mg/L (IQR 16.7-32.9). Our results show that, in PD patients, ascorbate deficiency is common and can readily be identified with serum ascorbate measurements. Oral supplements in the form of inexpensive multivitamin preparations restore adequate serum ascorbate levels in the majority of these patients. We therefore suggest measurement of ascorbate levels in all PD patients at the commencement of dialysis with a target level in the normal range (4-14 mg/L).

Synergistic efficacy of γ-radiation together with gallium trichloride and/or doxorubicin against Ehrlich carcinoma in female mice.

PubMed

Kandil, Eman; Aziz, Nahed Abdel

2016-02-01

Combining chemotherapy with radiotherapy represents a key oncology strategy for a more comprehensive attack toward cancers and improves treatment outcome for various solid tumor malignancies. The present study aims to evaluate the synergistic antitumor effect of γ-radiation together with gallium trichloride (GaCl3) and/or doxorubicin (DOX) against solid Ehrlich carcinoma (EC) in female mice. GaCl3 (300 mg/kg body weight (b.w.)) was administered by gavages daily on the seventh day after tumor inoculation, while the cytotoxic drug DOX (4 mg/kg b.w.) was administered intraperitoneally once a week. Whole-body γ-radiation was carried out at a dose 2 Gy once a week. Biochemical analysis showed that solid EC induced a significant increase in malondialdehyde (MDA) content with a significant decrease in the antioxidant state (glutathione peroxidase (GPx) and catalase (CAT) activities) and depleted serum iron concentration compared to normal control. Moreover, a significant increase was observed in calcium level and caspase-3 concentrations in both serum and tumor homogenate respectively associated with a significant alteration in heart, liver, and kidney functions, as compared to control. Treatment of EC-bearing mice with GaCl3and/or DOX combined with γ-radiation exposure significantly reduced tumor volume and displayed a significant improvement in most studied markers which may indicate a synergistic effect of this combination against organ dysfunction and cellular injury. The histopathologically investigation showed that treatment of animals bearing EC with GaCl3and/or DOX with γ-radiation exposure showed shrinkage in tumor lesions and wide zones of apoptotic cells with signs of regenerations. It was concluded that the combination of GaCl3and/or DOX with γ-radiation exposure resulted in super-additive cytotoxic effects on treatment of cancer cells.

Recent Progress on the Characterization of Aldonolactone Oxidoreductases

PubMed Central

Aboobucker, Siddique I; Lorence, Argelia

2015-01-01

l-Ascorbic acid (ascorbate, AsA, vitamin C) is essential for animal and plant health. Despite our dependence on fruits and vegetables to fulfill our requirement for this vitamin, the metabolic network leading to its formation in plants is just being fully elucidated. There is evidence supporting the operation of at least four biosynthetic pathways leading to AsA formation in plants. These routes use d-mannose/l-Galactose, l-gulose, d-galacturonate, and myo-inositol as the main precursors. This review focuses on aldonolactone oxidoreductases, a subgroup of the vanillyl alcohol oxidase (VAO; EC 1.1.3.38) superfamily, enzymes that catalyze the terminal step in AsA biosynthesis in bacteria, protozoa, animals, and plants. In this report, we review the properties of well characterized aldonolactone oxidoreductases to date. A shared feature in these proteins is the presence of a flavin cofactor as well as a thiol group. The flavin cofactor in many cases is bound to the N terminus of the enzymes or to a recently discovered HWXK motif in the C terminus. The binding between the flavin moiety and the protein can be either covalent or non-covalent. Substrate specificity and subcellular localization differ among the isozymes of each kingdom. All oxidases among these enzymes possess dehydrogenase activity, however, exclusive dehydrogenases are also found. We also discuss recent evidence indicating that plants have both l-gulono-1,4-lactone oxidases and l-Galactono-1,4-lactone dehydrogenases involved in AsA biosynthesis. PMID:26696130

Ascorbic acid deficiency leads to increased grain chalkiness in transgenic rice for suppressed of L-GalLDH.

PubMed

Yu, Le; Liu, Yonghai; Lu, Lina; Zhang, Qilei; Chen, Yezheng; Zhou, Liping; Chen, Hua; Peng, Changlian

2017-04-01

The grain chalkiness of rice (Oryza sativa L.), which determines the rice quality and price, is a major concern in rice breeding. Reactive oxygen species (ROS) plays a critical role in regulating rice endosperm chalkiness. Ascorbic acid (Asc) is a major plant antioxidant, which strictly regulates the levels of ROS. l-galactono-1, 4-lactone dehydrogenase (L-GalLDH, EC 1.3.2.3) is an enzyme that catalyzes the last step of Asc biosynthesis in higher plants. Here we show that the L-GalLDH-suppressed transgenic rice, GI-1 and GI-2, which have constitutively low (between 30% and 50%) leaf and grain Asc content compared with the wild-type (WT), exhibit significantly increased grain chalkiness. Further examination showed that the deficiency of Asc resulted in a higher lipid peroxidation and H 2 O 2 content, accompanied by a lower hydroxyl radical scavenging rate, total antioxidant capacity and photosynthetic ability. In addition, changes of the enzyme activities and gene transcript abundances related to starch synthesis were also observed in GI-1 and GI-2 grains. The results we presented here suggest a close correlation between Asc deficiency and grain chalkiness in the L-GalLDH-suppressed transgenics. Asc deficiency leads to the accumulation of H 2 O 2 , affecting antioxidant capacity and photosynthetic function, changing enzyme activities and gene transcript abundances related to starch synthesis, finally leading to the increased grain chalkiness. Copyright © 2017 Elsevier GmbH. All rights reserved.

Effect of platelets on apparent leucocyte ascorbic acid content.

PubMed

Evans, R M; Currie, L; Campbell, A

1980-09-01

The leucocyte ascorbic acid content is widely used as a measure of tissue ascorbic acid status. Standard methods of analysis, however, isolate both leucocytes and platelets (buffy layer), with consequent overestimation, since platelet ascorbic acid is attributed to the leucocytes. Fourteen healthy individuals on ascorbic acid supplements and 11 patients on mega dose ascorbic acid therapy were studied. A significant correlation was demonstrated between the 'leucocyte' ascorbic acid content and the platelet: leucocyte ratio (r = 0.70, P < 0.001). It is suggested that changes in the relative distribution of platelets and leucocytes in the blood will result in an apparent change in the 'leucocyte' ascorbic acid content regardless of any actual change in the ascorbic acid content of the cells.

Ascorbic acid insufficiency induces the severe defect on bone formation via the down-regulation of osteocalcin production

PubMed Central

Kim, Won; Bae, Seyeon; Kim, Hyemin; Kim, Yejin; Choi, Jiwon; Lim, Sun Young; Lee, Hei Jin; Lee, Jihyuk; Choi, Jiyea; Jang, Mirim; Lee, Kyoung Eun; Chung, Sun G.; Hwang, Young-il

2013-01-01

The L-gulono-γ-lactone oxidase gene (Gulo) encodes an essential enzyme in the synthesis of ascorbic acid from glucose. On the basis of previous findings of bone abnormalities in Gulo-/- mice under conditions of ascorbic acid insufficiency, we investigated the effect of ascorbic acid insufficiency on factors related to bone metabolism in Gulo-/- mice. Four groups of mice were raised for 4 weeks under differing conditions of ascorbic acid insufficiency, namely, wild type; ascorbic acid-sufficient Gulo-/- mice, 3-week ascorbic acid-insufficient Gulo-/- mice, and 4-week ascorbic acid-insufficient Gulo-/- mice. Four weeks of ascorbic acid insufficiency resulted in significant weight loss in Gulo-/- mice. Interestingly, average plasma osteocalcin levels were significantly decreased in Gulo-/- mice after 3 weeks of ascorbic acid insufficiency. In addition, the tibia weight in ascorbic acid-sufficient Gulo-/- mice was significantly higher than that in the other three groups. Moreover, significant decreases in trabecular bone volume near to the growth plate, as well as in trabecular bone attachment to the growth plate, were evident in 3- or 4-week ascorbic acid-insufficient Gulo-/-. In summary, ascorbic acid insufficiency in Gulo-/- mice results in severe defects in normal bone formation, which are closely related to a decrease in plasma osteocalcin levels. PMID:24386598

Citric acid assisted phytoremediation of copper by Brassica napus L.

PubMed

Zaheer, Ihsan Elahi; Ali, Shafaqat; Rizwan, Muhammad; Farid, Mujahid; Shakoor, Muhammad Bilal; Gill, Rafaqa Ali; Najeeb, Ullah; Iqbal, Naeem; Ahmad, Rehan

2015-10-01

Use of organic acids for promoting heavy metals phytoextraction is gaining worldwide attention. The present study investigated the influence of citric acid (CA) in enhancing copper (Cu) uptake by Brassica napus L. seedlings. 6 Weeks old B. napus seedlings were exposed to different levels of copper (Cu, 0, 50 and 100µM) alone or with CA (2.5mM) in a nutrient medium for 40 days. Exposure to elevated Cu levels (50 and 100µM) significantly reduced the growth, biomass production, chlorophyll content, gas exchange attributes and soluble proteins of B. napus seedlings. In addition, Cu toxicity increased the production of hydrogen peroxide (H2O2), malondialdehyde (MDA) and electrolyte leakage (EL) in leaf and root tissues of B. napus. Activities of antioxidant enzymes such as guaiacol peroxidase (POD), superoxide dismutase (SOD), catalases (CAT), ascorbate peroxidase (APX) in root and shoot tissues of B. napus were increased in response to lower Cu concentration (50µM) but increased under higher Cu concentration (100µM). Addition of CA into nutrient medium significantly alleviated Cu toxicity effects on B. napus seedlings by improving photosynthetic capacity and ultimately plant growth. Increased activities of antioxidant enzymes in CA-treated plants seems to play a role in capturing of stress-induced reactive oxygen species as was evident from lower level of H2O2, MDA and EL in CA-treated plants. Increasing Cu concentration in the nutrient medium significantly increased Cu concentration in in B. napus tissues. Cu uptake was further increased by CA application. These results suggested that CA might be a useful strategy for increasing phytoextraction of Cu from contaminated soils. Copyright © 2015 Elsevier Inc. All rights reserved.

Effects of ambient and elevated CO2 on growth, chlorophyll fluorescence, photosynthetic pigments, antioxidants, and secondary metabolites of Catharanthus roseus (L.) G Don. grown under three different soil N levels.

PubMed

Singh, Aradhana; Agrawal, Madhoolika

2015-03-01

Catharanthus roseus L. plants were grown under ambient (375 ± 30 ppm) and elevated (560 ± 25 ppm) concentrations of atmospheric CO2 at different rates of N supply (without supplemental N, 0 kg N ha(-1); recommended N, 50 kg N ha(-1); and double recommended N, 100 kg N ha(-1)) in open top chambers under field condition. Elevated CO2 significantly increased photosynthetic pigments, photosynthetic efficiency, and organic carbon content in leaves at recommended (RN) and double recommended N (DRN), while significantly decreased total nitrogen content in without supplemental N (WSN). Activities of superoxide dismutase, catalase, and ascorbate peroxidase were declined, while glutathione reductase, peroxidase, and phenylalanine-ammonia lyase were stimulated under elevated CO2. However, the responses of the above enzymes were modified with different rates of N supply. Elevated CO2 significantly reduced superoxide production rate, hydrogen peroxide, and malondialdehyde contents in RN and DRN. Compared with ambient, total alkaloids content increased maximally at recommended level of N, while total phenolics in WSN under elevated CO2. Elevated CO2 stimulated growth of plants by increasing plant height and numbers of branches and leaves, and the magnitude of increment were maximum in DRN. The study suggests that elevated CO2 has positively affected plants by increasing growth and alkaloids production and reducing the level of oxidative stress. However, the positive effects of elevated CO2 were comparatively lesser in plants grown under limited N availability than in moderate and higher N availability. Furthermore, the excess N supply in DRN has stimulated the growth but not the alkaloids production under elevated CO2.

Citrus tristeza virus (CTV) Causing Proteomic and Enzymatic Changes in Sweet Orange Variety “Westin”

PubMed Central

Dória, Milena Santos; de Sousa, Aurizângela Oliveira; Barbosa, Cristiane de Jesus; Costa, Márcio Gilberto Cardoso; Gesteira, Abelmon da Silva; Souza, Regina Martins; Freitas, Ana Camila Oliveira; Pirovani, Carlos Priminho

2015-01-01

Citrus Tristeza disease, caused by CTV (Citrus tristeza virus), committs citrus plantations around the world and specifically attacks phloem tissues of the plant. The virus exists as a mixture of more or less severe variants, which may or may not cause symptoms of Tristeza. The objective of this study was to analyze the changes caused by CTV in the proteome of stems of sweet orange, as well as in the activity and gene expression of antioxidant enzymes. The CTV-infected sweet orange displayed mild symptoms, which were characterized by the presence of sparse stem pitting throughout their stems. The presence of virus was confirmed by RT-PCR. Proteomic analysis by 2DE-PAGE-MS / MS revealed the identity of 40 proteins differentially expressed between CTV- infected and -non-infected samples. Of these, 33 were up-regulated and 7 were down-regulated in CTV-infected samples. Among the proteins identified stands out a specific from the virus, the coat protein. Other proteins identified are involved with oxidative stress and for this their enzymatic activity was measured. The activity of superoxide dismutase (SOD) was higher in CTV-infected samples, as catalase (CAT) showed higher activity in uninfected samples. The activity of guaiacol peroxidase (GPX) did not vary significantly between samples. However, ascorbate peroxidase (APX) was more active in the infected samples. The relative expression of the genes encoding CAT, SOD, APX and GPX was analyzed by quantitative real time PCR (RT-qPCR). The CTV-infected samples showed greater accumulation of transcripts, except for the CAT gene. This gene showed higher expression in the uninfected samples. Taken together, it can be concluded that the CTV affects the protein profile and activity and gene expression of antioxidant enzymes in plants infected by this virus. PMID:26207751

Antioxidant enzyme and osmotic adjustment changes in bean seedlings as affected by biochar under salt stress.

PubMed

Farhangi-Abriz, Salar; Torabian, Shahram

2017-03-01

Salinity damaged cellular membranes through overproduction of reactive oxygen species (ROS), while osmolytes and antioxidant capacities play a vital role in protecting plants from salinity caused oxidative damages. Biochar also could alleviate the negative impacts of salt stress in crops. The pot experiment was conducted to investigate the effects of biochar on some antioxidant enzyme activities and osmolyte adjustments of common bean (Phaseolus vulgaris L. cv. Derakhshan) under salinity stress. Bean plants were subjected to three salinity levels (non-saline, 6 and 12 dSm -1 of NaCl) and biochar treatments (non-biochar, 10% and 20% total pot mass). Shoot and root dry weights of bean were decreased at two salt stress treatments. Salinity increased the activity of catalase (CAT), ascorbate peroxidase (APX), peroxidase (POD), polyphenol oxidase (PPO) and superoxide dismutase (SOD), and the content of malondialdehyde (MDA), oxygen radicals (O 2•- ), and hydrogen peroxide (H 2 O 2 ) in leaf and root compared to control. Additionally, increased magnitudes of proline, glycine betaine, soluble sugar and soluble protein contents were more pronounced under 12 dSm -1 NaCl than those under 6 dSm -1 NaCl. In contrast, biochar applied to soil enhanced the shoot and root dry weight in comparison with the non-biochar treatment. Furthermore, all of the antioxidant activities of seedlings in soil treated with biochar, particularly at 20% biochar, declined. With the addition of biochar, the contents of MDA, O 2•- and H 2 O 2 displayed remarkable decrease, and the osmotic substances accumulation in leaves and roots also reduced. The presented results supported the view that biochar can contribute to protect common bean seedlings against NaCl stress by alleviating the oxidative stress. Copyright © 2016 Elsevier Inc. All rights reserved.

A meta-analysis of arbuscular mycorrhizal effects on plants grown under salt stress.

PubMed

Chandrasekaran, Murugesan; Boughattas, Sonia; Hu, Shuijin; Oh, Sang-Hyon; Sa, Tongmin

2014-11-01

Salt stress limits crop yield and sustainable agriculture in most arid and semiarid regions of the world. Arbuscular mycorrhizal fungi (AMF) are considered bio-ameliorators of soil salinity tolerance in plants. In evaluating AMF as significant predictors of mycorrhizal ecology, precise quantifiable changes in plant biomass and nutrient uptake under salt stress are crucial factors. Therefore, the objective of the present study was to analyze the magnitude of the effects of AMF inoculation on growth and nutrient uptake of plants under salt stress through meta-analyses. For this, data were compared in the context of mycorrhizal host plant species, plant family and functional group, herbaceous vs. woody plants, annual vs. perennial plants, and the level of salinity across 43 studies. Results indicate that, under saline conditions, AMF inoculation significantly increased total, shoot, and root biomass as well as phosphorous (P), nitrogen (N), and potassium (K) uptake. Activities of the antioxidant enzymes superoxide dismutase, catalase, peroxidase, and ascorbate peroxidase also increased significantly in mycorrhizal compared to nonmycorrhizal plants growing under salt stress. In addition, sodium (Na) uptake decreased significantly in mycorrhizal plants, while changes in proline accumulation were not significant. Across most subsets of the data analysis, identities of AMF (Glomus fasciculatum) and host plants (Acacia nilotica, herbs, woody and perennial) were found to be essential in understanding plant responses to salinity stress. For the analyzed dataset, it is concluded that under salt stress, mycorrhizal plants have extensive root traits and mycorrhizal morphological traits which help the uptake of more P and K, together with the enhanced production of antioxidant enzymes resulting in salt stress alleviation and increased plant biomass.

The involvement of wheat F-box protein gene TaFBA1 in the oxidative stress tolerance of plants.

PubMed

Zhou, Shu-Mei; Kong, Xiang-Zhu; Kang, Han-Han; Sun, Xiu-Dong; Wang, Wei

2015-01-01

As one of the largest gene families, F-box domain proteins have been found to play important roles in abiotic stress responses via the ubiquitin pathway. TaFBA1 encodes a homologous F-box protein contained in E3 ubiquitin ligases. In our previous study, we found that the overexpression of TaFBA1 enhanced drought tolerance in transgenic plants. To investigate the mechanisms involved, in this study, we investigated the tolerance of the transgenic plants to oxidative stress. Methyl viologen was used to induce oxidative stress conditions. Real-time PCR and western blot analysis revealed that TaFBA1 expression was up-regulated by oxidative stress treatments. Under oxidative stress conditions, the transgenic tobacco plants showed a higher germination rate, higher root length and less growth inhibition than wild type (WT). The enhanced oxidative stress tolerance of the transgenic plants was also indicated by lower reactive oxygen species (ROS) accumulation, malondialdehyde (MDA) content and cell membrane damage under oxidative stress compared with WT. Higher activities of antioxidant enzymes, including superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX) and peroxidase (POD), were observed in the transgenic plants than those in WT, which may be related to the upregulated expression of some antioxidant genes via the overexpression of TaFBA1. In others, some stress responsive elements were found in the promoter region of TaFBA1, and TaFBA1 was located in the nucleus, cytoplasm and plasma membrane. These results suggest that TaFBA1 plays an important role in the oxidative stress tolerance of plants. This is important for understanding the functions of F-box proteins in plants' tolerance to multiple stress conditions.

The Combined Effects of Arbuscular Mycorrhizal Fungi (AMF) and Lead (Pb) Stress on Pb Accumulation, Plant Growth Parameters, Photosynthesis, and Antioxidant Enzymes in Robinia pseudoacacia L.

PubMed Central

Liang, Yan; Ghosh, Amit; Chen, Jie; Tang, Ming

2015-01-01

Arbuscular mycorrhizal fungi (AMF) are considered as a potential biotechnological tool for improving phytostabilization efficiency and plant tolerance to heavy metal-contaminated soils. However, the mechanisms through which AMF help to alleviate metal toxicity in plants are still poorly understood. A greenhouse experiment was conducted to evaluate the effects of two AMF species (Funneliformis mosseae and Rhizophagus intraradices) on the growth, Pb accumulation, photosynthesis and antioxidant enzyme activities of a leguminous tree (Robinia pseudoacacia L.) at Pb addition levels of 0, 500, 1000 and 2000 mg kg-1 soil. AMF symbiosis decreased Pb concentrations in the leaves and promoted the accumulation of biomass as well as photosynthetic pigment contents. Mycorrhizal plants had higher gas exchange capacity, non-photochemistry efficiency, and photochemistry efficiency compared with non-mycorrhizal plants. The enzymatic activities of superoxide dismutase (SOD), ascorbate peroxidases (APX) and glutathione peroxidase (GPX) were enhanced, and hydrogen peroxide (H2O2) and malondialdehyde (MDA) contents were reduced in mycorrhizal plants. These findings suggested that AMF symbiosis could protect plants by alleviating cellular oxidative damage in response to Pb stress. Furthermore, mycorrhizal dependency on plants increased with increasing Pb stress levels, indicating that AMF inoculation likely played a more important role in plant Pb tolerance in heavily contaminated soils. Overall, both F. mosseae and R. intraradices were able to maintain efficient symbiosis with R. pseudoacacia in Pb polluted soils. AMF symbiosis can improve photosynthesis and reactive oxygen species (ROS) scavenging capabilities and decrease Pb concentrations in leaves to alleviate Pb toxicity in R. pseudoacacia. Our results suggest that the application of the two AMF species associated with R. pseudoacacia could be a promising strategy for enhancing the phytostabilization efficiency of Pb contaminated soils. PMID:26698576

Metabolic similarities between fertilization and phagocytosis. Conservation of a peroxidatic mechanism

PubMed Central

1979-01-01

At the time of fertilization, sea urchin eggs release a peroxidase which, together with H2O2 generated by a respiratory burst, is responsible for hardening of the fertilization membrane. We demonstrate here that the ovoperoxidase of unfertilized eggs is located in cortical granules and, after fertilization, is concentrated in the fertilization membrane. Fertilization of sea urchin eggs or their parthenogenetic activation with the ionophor A23187 also results in (a) the conversion of iodide to a trichloroacetic acid-precipitable form (iodination), (b) the deiodination of eggs exogenously labeled with myeloperoxidase and H2O2, (c) the degradation of thyroxine as measured by the recovery of the released radioiodine at the origin and in the inorganic iodide spot on paper chromatography, and (d) the conversion of estradiol to an alcohol-precipitable form (estrogen binding). The iodination reaction and the binding of estradio occurs predominantly in the fertilization membrane where the ovoperoxidase is concentrated. From the estimation of the kinetics of incorporation of iodine, we determine that the peroxidative system is active for 30 min after fertilization, long after hardening of the fertilization membrane is complete. Most of the bound iodine is lost during the hatching process. Iodination of albumin is catalyzed by the material released from the egg during fertilization, when combined with H2O2 and iodide. Iodination, thyroxine degradation, and estradiol binding are inhibited by azide, cyanide, aminotriazole, methimazole, ascorbic acid and ergothioneine, all of which can inhibit peroxidase-catalyzed reactions. These responses of the sea urchin egg to fertilization are strikingly similar to the changes induced in polymorphonuclear leukocytes by phagocytosis and, in both instances, a peroxidative mechanism may be involved. PMID:372484

Drought increases cowpea (Vigna unguiculata [L.] Walp.) susceptibility to cowpea severe mosaic virus (CPSMV) at early stage of infection.

PubMed

Silva, Rodolpho G G; Vasconcelos, Ilka M; Martins, Thiago F; Varela, Anna L N; Souza, Pedro F N; Lobo, Ana K M; Silva, Fredy D A; Silveira, Joaquim A G; Oliveira, Jose T A

2016-12-01

The physiological and biochemical responses of a drought tolerant, virus-susceptible cowpea genotype exposed to drought stress (D), infected by Cowpea severe mosaic virus (CPSMV) (V), and to these two combined stresses (DV), at 2 and 6 days post viral inoculation (DPI), were evaluated. Gas exchange parameters (net photosynthesis, transpiration rate, stomatal conductance, and internal CO 2 partial pressure) were reduced in D and DV at 2 and 6 DPI compared to control plants (C). Photosynthesis was reduced by stomatal and biochemical limitations. Water use efficiency increased at 2 DPI in D, DV, and V, but at 6 DPI only in D and DV compared to C. Photochemical parameters (effective quantum efficiency of photosystem II and electron transport rate) decreased in D and DV compared to C, especially at 6 DPI. The potential quantum efficiency of photosystem II did not change, indicating reversible photoinhibition of photosystem II. In DV, catalase decreased at 2 and 6 DPI, ascorbate peroxidase increased at 2 DPI, but decreased at 6 DPI. Hydrogen peroxide increased at 2 and 6 DPI. Peroxidase increased at 6 DPI and chitinase at 2 and 6 DPI. β-1,3-glucanase decreased in DV at 6 DPI compared to V. Drought increased cowpea susceptibility to CPSMV at 2 DPI, as verified by RT-PCR. However, at 6 DPI, the cowpea plants overcome this effect. Likewise, CPSMV increased the negative effects of drought at 2 DPI, but not at 6 DPI. It was concluded that the responses to combined stresses are not additive and cannot be extrapolated from the study of individual stresses. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Copper-resistant bacteria reduces oxidative stress and uptake of copper in lentil plants: potential for bacterial bioremediation.

PubMed

Islam, Faisal; Yasmeen, Tahira; Ali, Qasim; Mubin, Muhammad; Ali, Shafaqat; Arif, Muhammad Saleem; Hussain, Sabir; Riaz, Muhammad; Abbas, Farhat

2016-01-01

For effective microbe-assisted bioremediation, metal-resistant plant growth-promoting bacteria (PGPB) must facilitate plant growth by restricting excess metal uptake in plants, leading to prevent its bio-amplification in the ecosystem. The aims of our study were to isolate and characterize copper (Cu)-resistant PGPB from waste water receiving contaminated soil. In addition, we investigated the phytotoxic effect of copper on the lentil plants inoculated with copper-resistant bacteria Providencia vermicola, grown in copper-contaminated soil. Copper-resistant P. vermicola showed multiple plant growth promoting characteristics, when used as a seed inoculant. It protected the lentil plants from copper toxicity with a considerable increase in root and shoot length, plant dry weight and leaf area. A notable increase in different gas exchange characteristics such as A, E, C i , g s , and A/E, as well as increase in N and P accumulation were also recorded in inoculated plants as compared to un-inoculated copper stressed plants. In addition, leaf chlorophyll content, root nodulation, number of pods, 1,000 seed weight were also higher in inoculated plants as compared with non-inoculated ones. Anti-oxidative defense mechanism improved significantly via elevated expression of reactive oxygen species -scavenging enzymes including ascorbate peroxidase, superoxide dismutase, catalase, and guaiacol peroxidase with alternate decrease in malondialdehyde and H2O2 contents, reduced electrolyte leakage, proline, and total phenolic contents suggesting that inoculation of P. vermicola triggered heavy metals stress-related defense pathways under copper stress. Overall, the results demonstrated that the P. vermicola seed inoculation confer heavy metal stress tolerance in lentil plant which can be used as a potent biotechnological tool to cope with the problems of copper pollution in crop plants for better yield.

Manganese deficiency in Chlamydomonas results in loss of photosystem II and MnSOD function, sensitivity to peroxides, and secondary phosphorus and iron deficiency.

PubMed

Allen, Michael D; Kropat, Janette; Tottey, Stephen; Del Campo, José A; Merchant, Sabeeha S

2007-01-01

For photoheterotrophic growth, a Chlamydomonas reinhardtii cell requires at least 1.7 x 10(7) manganese ions in the medium. At lower manganese ion concentrations (typically <0.5 microm), cells divide more slowly, accumulate less chlorophyll, and the culture reaches stationary phase at lower cell density. Below 0.1 microm supplemental manganese ion in the medium, the cells are photosynthetically defective. This is accompanied by decreased abundance of D1, which binds the Mn(4)Ca cluster, and release of the OEE proteins from the membrane. Assay of Mn superoxide dismutase (MnSOD) indicates loss of activity of two isozymes in proportion to the Mn deficiency. The expression of MSD3 through MSD5, encoding various isoforms of the MnSODs, is up-regulated severalfold in Mn-deficient cells, but neither expression nor activity of the plastid Fe-containing superoxide dismutase is changed, which contrasts with the dramatically increased MSD3 expression and plastid MnSOD activity in Fe-deficient cells. Mn-deficient cells are selectively sensitive to peroxide but not methyl viologen or Rose Bengal, and GPXs, APX, and MSRA2 genes (encoding glutathione peroxidase, ascorbate peroxidase, and methionine sulfoxide reductase 2) are slightly up-regulated. Elemental analysis indicates that the Mn, Fe, and P contents of cells in the Mn-deficient cultures were reduced in proportion to the deficiency. A natural resistance-associated macrophage protein homolog and one of five metal tolerance proteins were induced in Mn-deficient cells but not in Fe-deficient cells, suggesting that the corresponding gene products may be components of a Mn(2+)-selective assimilation pathway.

Manganese Deficiency in Chlamydomonas Results in Loss of Photosystem II and MnSOD Function, Sensitivity to Peroxides, and Secondary Phosphorus and Iron Deficiency1[W][OA

PubMed Central

Allen, Michael D.; Kropat, Janette; Tottey, Stephen; Del Campo, José A.; Merchant, Sabeeha S.

2007-01-01

For photoheterotrophic growth, a Chlamydomonas reinhardtii cell requires at least 1.7 × 107 manganese ions in the medium. At lower manganese ion concentrations (typically <0.5 μm), cells divide more slowly, accumulate less chlorophyll, and the culture reaches stationary phase at lower cell density. Below 0.1 μm supplemental manganese ion in the medium, the cells are photosynthetically defective. This is accompanied by decreased abundance of D1, which binds the Mn4Ca cluster, and release of the OEE proteins from the membrane. Assay of Mn superoxide dismutase (MnSOD) indicates loss of activity of two isozymes in proportion to the Mn deficiency. The expression of MSD3 through MSD5, encoding various isoforms of the MnSODs, is up-regulated severalfold in Mn-deficient cells, but neither expression nor activity of the plastid Fe-containing superoxide dismutase is changed, which contrasts with the dramatically increased MSD3 expression and plastid MnSOD activity in Fe-deficient cells. Mn-deficient cells are selectively sensitive to peroxide but not methyl viologen or Rose Bengal, and GPXs, APX, and MSRA2 genes (encoding glutathione peroxidase, ascorbate peroxidase, and methionine sulfoxide reductase 2) are slightly up-regulated. Elemental analysis indicates that the Mn, Fe, and P contents of cells in the Mn-deficient cultures were reduced in proportion to the deficiency. A natural resistance-associated macrophage protein homolog and one of five metal tolerance proteins were induced in Mn-deficient cells but not in Fe-deficient cells, suggesting that the corresponding gene products may be components of a Mn2+-selective assimilation pathway. PMID:17085511

Composition and functional property of photosynthetic pigments under circadian rhythm in the cyanobacterium Spirulina platensis.

PubMed

Kumar, Deepak; Kannaujiya, Vinod K; Richa; Pathak, Jainendra; Sundaram, Shanthy; Sinha, Rajeshwar P

2018-05-01

Circadian rhythm is an important endogenous biological signal for sustainable growth and development of cyanobacteria in natural ecosystems. Circadian effects of photosynthetically active radiation (PAR), ultraviolet-A (UV-A) and ultraviolet-B (UV-B) radiations on pigment composition have been studied in the cyanobacterium Spirulina platensis under light (L)/dark (D) oscillation with a combination of 4/20, 8/16, 12/12, 16/8, 20/4 and 24/24 h time duration. Circadian exposure of PAR + UV-A (PA) and PAR + UV-A + UV-B (PAB) showed more than twofold decline in Chl a, total protein and phycocyanin (PC) in light phase and significant recovery was achieved in dark phase. The fluorescence emission wavelength of PC was shifted towards lower wavelengths in the light phase of PAB in comparison to P and PA whereas the same wavelength was retrieved in the dark phase. The production of free radicals was accelerated twofold in the light phase (24 h L) whereas the same was retrieved to the level of control during the dark phase. Oxidatively induced damage was alleviated by antioxidative enzymes such as catalase (CAT), peroxidase (POD), superoxide dismutase (SOD) and ascorbate peroxidase (APX) in the light phase (0-24-h L) whereas the dark phase showed significant inhibition of the same enzymes. Similar characteristic inhibition of free radicals and recovery of PC was observed inside cellular filament after circadian rhythm of 24/24 h (L/D). Circadian exposure of P, PA and PAB significantly altered the synthesis and recovery of pigments that could be crucial for optimization and sustainable production of photosynthetic products for human welfare.

Photosynthesis is improved by exogenous calcium in heat-stressed tobacco plants.

PubMed

Tan, Wei; Meng, Qing wei; Brestic, Marian; Olsovska, Katarina; Yang, Xinghong

2011-11-15

Effects of exogenous calcium chloride (CaCl(2)) (20 mM) on photosynthetic gas exchange, photosystem II photochemistry, and the activities of antioxidant enzymes in tobacco plants under high temperature stress (43°C for 2 h) were investigated. Heat stress resulted in a decrease in net photosynthetic rate (P(n)), stomatal conductance as well as the apparent quantum yield (AQY) and carboxylation efficiency (CE) of photosynthesis. Heat stress also caused a decrease of the maximal photochemical efficiency of primary photochemistry (F(v)/F(m)). On the other hand, CaCl(2) application improved P(n), AQY, and CE as well as F(v)/F(m) under high temperature stress. Heat stress reduced the activities of superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), peroxidase (POD), whereas the activities of these enzymes either decreased less or increased in plants pretreated with CaCl(2); glutathione reductase (GR) activity increased under high temperature, and it increased more in plants pretreated with CaCl(2). There was an obvious accumulation of H(2)O(2) and O(2)(-) under high temperature, but CaCl(2) application decreased the contents of H(2)O(2) and O(2)(-) under heat stress conditions. Heat stress induced the level of heat shock protein 70 (HSP70), while CaCl(2) pretreatment enhanced it. These results suggested that photosynthesis was improved by CaCl(2) application in heat-stressed plants and such an improvement was associated with an improvement in stomatal conductance and the thermostability of oxygen-evolving complex (OEC), which might be due to less accumulation of reactive oxygen species. Copyright © 2011 Elsevier GmbH. All rights reserved.

Combating photooxidative stress in green hairy roots of Daucus carota cultivated under light irradiation.

PubMed

Mukherjee, Chiranjit; Sircar, Debabrata; Chatterjee, Moniya; Das, Sampa; Mitra, Adinpunya

2014-01-15

The light-dependent generation of active oxygen species, which can disrupt normal metabolic process of plant, is termed as photo-oxidative stress. Plants are equipped with enzymatic and non-enzymatic antioxidative defence system to reduce the effect of such stress. Hairy root culture of Daucus carota when cultivated under continuous illumination (250 μmol m(-2)s(-1)) turned green. To know the reason behind that and photo-oxidative stress response in green hairy roots, activities of several antioxidant enzymes were measured. When compared with normal hairy roots, green hairy roots showed an enhanced superoxide dismutase (SOD) activity. Treatment with a SOD inhibitor diethyldithiocarbamate led to suppression of SOD activity in a concentration-dependent manner in green hairy roots. Interestingly, SOD-suppressed root showed three-fold enhanced caffeic acid glucoside accumulation in the soluble fraction as compared to untreated ones. While ascorbate peroxidase activity showed marginal increase in green hairy roots, a decrease in the activities of guaiacol peroxidase and catalase were observed. SDS-PAGE of crude protein profile from green hairy roots showed a distinct band, which was absent in normal hairy roots. MALDI-TOF-MS/MS analysis of the extracted protein confirmed it as the large subunit of RuBisCO. RT-PCR based expression analysis of betaine aldehyde dehydrogenase showed enhanced transcript levels in green hairy roots as compared to normal hairy roots, whereas reverse trends were observed with the transcripts accumulation for phenylalanine ammonia-lyase and chalcone synthase. These findings corroborate with the in vitro BADH activities in hairy roots, and thus indicate an important role of this stress enzyme in combating photo-oxidative stress in green hairy roots upon continuous light exposure. Copyright © 2013 Elsevier GmbH. All rights reserved.