Active Oxygen Species Metabolism Research Articles

Regulation of plum fruit cracking process during cold storage period by treatment of preharvest chitosan

Cracking fruit is a serious quality change phenomenon in the storage and transportation of postharvest plum fruit. To reduce the cracking rate of plum fruit during cold storage, the 'Guofeng No.7′ plum was sprayed with chitosan with 1.5% concentration 30d from preharvest. The postharvest plum fruit was stored at (0 ± 0.5) °C and (85–90) % relative humidity. The results showed that chitosan treatment could reduce the reactive oxygen species (ROS) level of plum fruit, effectively delaying the fruit cracking. Compared with the control, chitosan treated fruits inhibited the increase of free radical content such as O2−· and H2O2 and delayed the increase of membrane permeability and the accumulation of MDA (from 71.9 mmol/g to 53.5 mmol/g). It also regulates lipoxygenase (LOX), peroxidase (POD), superoxide dismutase (SOD), catalase (CAT) (enzymatic activity from 34.15 g/min to 42.21 g/min) and ascorbate peroxidase (APX) activity and gene expression during fruit cracking to maintain membrane integrity and intracellular compartmentalization, thereby increasing the crack tolerance of plum fruit during cold storage. These results indicate that preharvest chitosan treatment can inhibit the metabolism of active oxygen species, increase the activity of ROS scavenging enzymes and gene expression, and delay the postharvest cracking of plum fruit.

Effects of soil trace metals, organic carbon load and physicochemical stressors on active oxygen species metabolism in Scylla serrata sampled along the Bay of Bengal in Odisha state, India

Studies on the synergetic effects of soil and water parameters on Oxidative Stress (OS) physiology systems of the edible mud crab Scylla serrata sampled from different parts of East India are unknown. This study aimed to evaluate the effects of soil Ca, Mg, and organic carbon load and water physicochemical stressors induced spatio-temporal variation of tissue-specific OS and antioxidant parameters in S. serrata along the Bay of Bengal in Odisha. Spectrophotometric or Fourier-transform infrared spectroscopy methods were employed to measure the OS physiology and physicochemical parameters. Pedological and physicochemical factors of water were varied significantly in summer (38–42°C), rainy (25–35°C), and winter (12–20°C) seasons. Activities of antioxidant enzymes (AE) such as superoxide dismutase (SOD), catalase, glutathione peroxidase (GPx), and the level of lipid peroxidation (LPx) were found to be higher in hepatopancreas as compared to other tissues irrespective of seasonal variation. Considering the impact of dry seasons, an average of 13.23% enhanced activities of AE were noticed in different tissues of S. serrata in response to temperature, salinity, organic carbon, Mg, and Ca load of sampling sites. However, about 11.26% decrease in the activities of AEs, including GR and GST in most of the tissues were recorded, along with a 21% alleviated level of LPx observed in the rainy season compared to other seasons. Among three coastal zones of the Bay of Bengal, the AEs in crabs sampled from Chandipur were elevated by 5.43% in winter, whereas a 7.05% enhanced level of LPx was found in summer compared to crabs sampled from Chilika and Jagatsinghpur. Overall, the levels of LPx, total antioxidant, and activities of AEs (CAT, GST, GPx, and GR) have shown a positive correlation, whereas ascorbic acid and GSH negatively correlate with habitat water pH, temperature, and salinity of soil and water. The results can be used for ecotoxic and environmental biomonitoring purposes using crabs as model organisms across tropical coastal regions.

Myasthenia gravis: The pharmacological basis of traditional Chinese medicine for its clinical application.

We aimed to investigate the target and signal pathway of Smilacis Glabrae Rhixoma (SGR) in the treatment of myasthenia gravis (MG) based on network pharmacology, and to explore its potential molecular mechanism. The main active components of SGR were searched in the pharmacology database of traditional Chinese medicine systems, and analysis platform. The related targets of SGR were obtained by Genecards, connective tissue disease, therapeutic target database, Drugbank, and Online Mendelian Inheritance in Man database. Moreover, the target information was corrected through UniProtKB and also, this data integrated to draw the "Ingredients-targets" network of SGR. Protein interaction analysis was performed in data platform, gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways as well as enrichment analysis on disease-drug target was carried out through metascape online platform. A total of 15 active components were collected from SGR, which correspond to 159 targets; There were 1758 MG-related targets; there are 81 targets related to both drug components and diseases, including 12 key targets. In GO bioaccumulation analysis, 1933 GO items were gathered, which were mainly related to the metabolism of active oxygen species and the active factors of postsynaptic neurotransmitter receptor. According to KEGG analysis, SGR may play a role in the treatment of MG through phosphatidylinositol-3-kinase-protein kinase B signaling pathway, T-cell receptor, cAMP, tumor necrosis factor (TNF), and interleukin-17 (IL-17) signaling pathway, Th17 cell differentiation, endocrine resistance, hepatitis, and some cancer pathways. This study shows that SGR mainly treat myasthenia gravis through the regulation of TNF, MAPK1, JUN, TP53 and other targets, T-cell receptor, TNF, and IL-17 signaling pathway, Th17 cell differentiation and other pathways, which reflects the characteristics of multicomponent, multitarget, and multichannel of traditional Chinese medicine, and providing a certain pharmacological basis for the follow-up study.

Active oxygen species metabolism in neem (Azadirachta indica) seeds exposed to natural ageing and controlled deterioration

Success of ex situ storage of germplasm for trade and conservation essentially depends upon the precision of the protocol employed for the assessment of germination potential. Active oxygen species and antioxidative enzymes during natural ageing (NA) and controlled deterioration (CD) was monitored during the loss of seed vigour and germination potential in neem seeds showing intermediate seed storage behaviour. Higher levels of SOD, CAT and APX were strongly and positively associated with germination and vigour. The loss of CAT and APX activity estimated quantitatively and number of isoenzymes were closely accompanied with the simultaneous increase in the amounts of H2O2 and OH-radical. The decline in germination and vigour was negatively related with the levels of H2O2 and OH-radical and enhanced electrolyte leakage. The amounts of OH-radical were positively correlated with the decline in DNA content and DNA damage. The levels of SOD isoenzymes initially increased as the germination index of seeds declined from 5250 to 762 and 882 under NA and CD conditions, respectively. Increasing activity of SOD in the ageing seeds were associated with the accumulation of H2O2. The role of antioxidative enzymes in maintaining signalling and damaging amounts of AOS as well as revelations of different pathways of ageing during NA and CD in the ageing neem seeds were discussed.

Combined effects of water temperature and copper ion concentration on catalase activity in Crassostrea ariakensis

A central composite experimental design and response surface method were used to investigate the combined effects of water temperature (18–34°C) and copper ion concentration (0.1–1.5 mg/L) on the catalase (CAT) activity in the digestive gland of Crassostrea ariakensis. The results showed that the linear effects of temperature were significant (P 0.05), and the quadratic effects of copper ion concentration were significant (P 0.05), and the effect of temperature was greater than that of copper ion concentration. A model equation of CAT enzyme activity in the digestive gland of C. ariakensis toward the two factors of interest was established, with R 2, Adj. R 2 and Pred. R 2 values as high as 0.943 7, 0.887 3 and 0.838 5, respectively. These findings suggested that the goodness of fit to experimental data and predictive capability of the model were satisfactory, and could be practically applied for prediction under the conditions of the study. Overall, the results suggest that the simultaneous variation of temperature and copper ion concentration alters the activity of the antioxidant enzyme CAT by modulating active oxygen species metabolism, which may be utilized as a biomarker to detect the effects of copper pollution.

Influence of Ca2+ ions on metabolism of active oxygen species in wheat calli cocultured with the bunt pathogen Tilletia caries

The effect of Ca2+ on morphophysiological parameters of wheat calli (Triticum aestivum L.) infected by the bunt pathogen Tilletia caries, in particular on the level of active oxygen species, activity of oxalate oxidase, peroxidase, and catalase is investigated. The concentration of O2−, H2O2, and activity of oxidoreductases (oxalate oxidase, peroxidase, and catalase) depended on the content of Ca2+ in the culture medium of calli. The increase of the concentration of Ca2+ ions in the culture medium led to forming of calli with high structure, induction of activity of oxalate oxidase and of some isoperoxidase, and to accumulation of active oxygen species. These changes contributed to inhibition of development of the fungus. So this dependence confirm the role of calcium as the intermediant in biochemical reactions related to the formation of the protective response of plant cells to biotic stress.

Impact of solar ultraviolet-B radiation on the antioxidant defense system in soybean lines differing in flavonoid contents

Exposure to ultraviolet-B (UV-B) radiation can lead to oxidative damage in plants. However, plants possess a number of UV-protection mechanisms including screening of potentially damaging UV-B and increased production or activities of antioxidants. The balance or trade-off between these two mechanisms has rarely been studied and is poorly understood. Two isolines of soybean ( Glycine max [L.] Merr.) Clark cultivar, the normal line with moderate levels of flavonoids and the magenta line with reduced flavonoids levels, were grown in the field with or without natural levels of UV-B. Leaflet blades of the first trifoliate leaf were harvested after 4–12 days of exposure to the experimental conditions for analysis of active oxygen species (AOS) and antioxidant levels. Solar UV-B radiation caused oxidative stress in both lines and altered AOS metabolism primarily by decreasing superoxide dismutase activity and increasing the activities of ascorbate peroxidase, catalase and glutathione reductase. This resulted in decreased ascorbic acid content and increased dehydroascorbate content. The magenta line had greater oxidative stress than the normal line in spite of its enhanced oxidative defense capacity as compared to the normal line, even under UV-B exclusion. These results indicate enhanced sensitivity in the magenta line, especially under UV-B exclusion that was likely due to the absence of flavonoid epidermal screening compounds and subsequent increased penetration of solar ultraviolet radiation into the leaf.

Effects of exogenous nitric oxide on growth, active oxygen species metabolism, and photosynthetic characteristics in cucumber seedlings under NaCl stress

The study was conducted by means of nutrient solution culture to investigate the effects of exogenous nitric oxide (NO) on growth of cucumber seedlings, active oxygen species metabolism and photosynthetic characteristics in cucumber leaves under 50 mmol/L NaCl stress. The results showed that 10–400 µmol/L exogenous sodium nitroprusside (SNP), especially 100 µmol/L SNP, significantly alleviated the injury to seedlings and increased seedling growth. The activity of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and ascorbate peroxidase (APX), and the contents of photosynthetic pigments and proline also increased under 50 mmol/L NaCl stress. Similarly, net photosynthetic rate (Pn), stomatal conductance (Gs), and transpiration rate (Tr) also increased significantly. However, exogenous nitric oxide application markedly decreased membrane permeability, rate of O 2 .− production, the contents of malondialdehyde (MDA) and H2O2, and intercellular CO2 concentration (Ci) under 50 mmol/L NaCl stress.

Inhibition of Blumeria graminis f. sp. tritici Germination and Partial Enhancement of Wheat Defenses by Milsana

ABSTRACT The prophylactic efficiency of Milsana against powdery mildew was evaluated on wheat (Triticum aestivum). A single short spraying on 10-day-old plantlets reduced the infection level by 85% and two long sprayings led to the total restriction of the disease. Although microscopic studies showed that Milsana treatments enhance hydrogen peroxide accumulation at the fungal penetration site, biochemical analysis did not allow us to correlate this accumulation with the activation of several enzyme activities involved in active oxygen species (AOS) metabolism. Only lipoxygenase activity, which is involved in both AOS metabolism and lipid peroxidation, showed a 26 to 32% increase 48-h posttreatment in leaves infiltrated with Milsana. This weak effect of Milsana on wheat lipid metabolism was confirmed at the lipid peroxidation level, which surprisingly, was shown to decrease in treated plants. In order to explain the high efficacy of Milsana, the fungistatic effect on conidia germination was also examined. In planta, we showed that a Milsana treatment resulted in a higher proportion of abnormally long appressorial germ tubes, whereas in vitro, it dramatically inhibited fungal conidia germination. The partial activity of Milsana in terms of defense response induction in the wheat/powdery mildew pathosystem and its newly described direct fungistatic activity are discussed.

Glutathione peroxidases of the potato cyst nematode Globodera Rostochiensis.

We report the cloning and characterisation of full-length DNAs complementary to RNA (cDNAs) encoding two glutathione peroxidases (GpXs) from a plant parasitic nematode, the potato cyst nematode (PCN) Globodera rostochiensis. One protein has a functional signal peptide that targets the protein for secretion from animal cells while the other is predicted to be intracellular. Both genes are expressed in all parasite stages tested. The mRNA encoding the intracellular GpX is present throughout the nematode second stage juvenile and is particularly abundant in metabolically active tissues including the genital primordia. The mRNA encoding the secreted GpX is restricted to the hypodermis, the outermost cellular layer of the nematode, a location from which it is likely to be secreted to the parasite surface. Biochemical studies confirmed the secreted protein as a functional GpX and showed that, like secreted GpXs of other parasitic nematodes, it does not metabolise hydrogen peroxide but has a preference for larger hydroperoxide substrates. The intracellular protein is likely to have a role in metabolism of active oxygen species derived from internal body metabolism while the secreted protein may protect the parasite from host defences. Other functional roles for this protein are discussed.

Evidence for Oxidative Stress Involved in Physiological Leaf Spot Formation in Winter and Spring Barley

ABSTRACT A leaf spot disease with unknown etiology has become more pronounced in spring and winter barley in Germany in recent years. The symptoms are similar to net blotch and Ramularia leaf spots, but the causal agents of these diseases are not identified. The symptom expression varied much on cultivars. Cultivars most affected by the disease of both spring and winter barley showed a significantly higher level of superoxide (O(2) ) production and lipid peroxidation (malondialdehyde), but a lower level of antioxidant potential expressed as superoxide dismutase (SOD) activity, catalase activity, and integral water-soluble antioxidant capacity (ACW) than insensitive cultivars. A high positive correlation between O(2) production and leaf spot development between ear emergence and milk ripeness was established in the most sensitive winter barley cv. Anoa (r(2) = 0.9622) and spring barley cv. Barke (r(2) = 0.9434). Leaf H(2)O(2) levels increased with the severity of leaf spots. The histochemical localization of O(2) and H(2)O(2) in the tissues adjacent to leaf spots indicated that these two active oxygen species (AOS) are involved in the formation of leaf spots. Reduction of symptom severity by applying strobilurin and azole fungicides was always associated with elevated SOD activity and ACW content and suppressed O(2) production. However, peroxidase activities were significantly higher in sensitive cultivars and in more severely affected tissues and decreased by applying fungicides. Thus, it is assumed that a possible genetic mechanism based on the imbalanced AOS metabolism contributes to formation of physiological leaf spots.

Differential leaf stress responses in young and senescent plants

Responses to low temperature, mechanical wounding and salicylic acid (SA) treatments were studied in 3-week-old (young) and 6-week-old (senescent) Arabidopsis thaliana (L.) Heynh. plants by analyzing increases in Pal1 and Pr1 expression and superoxide dismutase (SOD; EC 1.15.1.1) and peroxidase (POX; EC 1.11.1.7) activities. Young plants showed higher Pal1 transcript accumulation after low temperature and wounding. In contrast, senescent plants presented higher accumulation of Pr1 transcripts after SA treatments. Similar results were obtained with the ethylene-insensitive etr1 mutant, suggesting that these differences are not related to increased ethylene content in senescent tissues. SOD activity and inducibility were lower, whereas POX activity and inducibility were higher in senescent plants. A possible relationship between senescence-associated changes in responses to stress and in the metabolism of active oxygen species is discussed.

Active Oxygen Species Metabolism in `White Angel' × `Rome Beauty' Apple Selections Resistant and Susceptible to Superficial Scald

Fruit from seedlings selected from a population obtained by crossing superficial scald-resistant `White Angel' and superficial scald-susceptible `Rome Beauty' apple (Malus ×domestica Borkh.) were used to investigate the role of oxidative processes in the development of superficial scald. Selections were identified for study based on fruit coloration and scald susceptibility. Plant material had one of the following three physiognomies: 1) red-skinned fruit resistant to scald; 2) red-skinned fruit susceptible to scald; and 3) yellow-skinned fruit susceptible to scald. The concentrations of α-farnesene, conjugated triene (CT) species, hydrogen peroxide (H2O2), thiobarbituric acid-reactive substances, carbonyl groups, and the activities of superoxide dismutase, guaiacol-peroxidase, and catalase were measured at harvest and during 0.5 °C storage. Relationships were poor between scald susceptibility and α-farnesene and its oxidation products, CT258, CT281, and the CT258/CT281 ratio. Tissue concentrations of H2O2 were lower in scald-resistant than in scald-susceptible fruit at harvest and after storage, and these lower concentrations were associated with less damage to cellular membranes (lipid peroxidation) and proteins (carbonyl group content). Higher activities of the H2O2-degrading enzymes, guaiacol-peroxidases, and catalases, were related to lower H2O2 content and lower scald susceptibility. Activities of superoxide dismutase, a H2O2-generating enzyme, were not related to scald susceptibility or storage period. We hypothesize that fruit susceptibility to scald is strongly influenced by cellular efficiency in metabolizing active oxygen species such as H2O2.

Changes in the Activities of Anti-Oxidant Enzymes during Exposure of Intact Wheat Leaves to Strong Visible Light at Different Temperatures in the Presence of Protein Synthesis Inhibitors.

Changes in activities of the enzymes involved in the metabolism of active oxygen species were followed in homogenates prepared from wheat leaves (Triticum aestivum L.) exposed to strong visible light (600 W m-2). The activities of superoxide dismutase (SOD), ascorbate peroxidase, and monodehydroascorbate reductase increased significantly on prolonged illumination of the leaves, indicating an increase in the rate of generation of active oxygen species. This increase was further exacerbated when high light stress was combined with low temperature (8[deg]C). Our results indicate that the increase in activities of SOD and ascorbate peroxidase involved de novo protein synthesis that was sensitive to the nuclear-directed protein synthesis inhibitor cycloheximide. The activity of catalase, on the other hand, decreased on exposure to strong light, which could be due to its photolability, particularly at lower temperatures. Ascorbate and total carotenoid contents also increased on light treatment of the leaves. The induction of the enzymes except for catalase and increase in the levels of ascorbate and total carotenoids in response to the stress conditions indicate that they play an important role in the protection of higher plants from the damaging effects of toxic active species.

Application of a new ion exchanger TSK-GEL DEAE-5PW, to the purification of Cu,Zn-superoxide dismutase of bovine erythrocytes

We have developed an effective method for the purification of Cu,Zn-superoxide dismutase [E.C. 1.15.1.1] from bovine erythrocytes. This enzyme functions as a scavenger of superoxide radical, and it seems to be a key enzyme in the metabolism of active oxygen species. Application of this enzyme as a drug has been considered, and for this purpose a highly purified preparation is necessary. The first purification of this enzyme was reported by McCord and Fridovich [ J. Biol. Chem., 244 (1969) 6049]. The limiting step in their method is the removal of the small amount of contaminating protein from the acetone-precipitated crude preparation (3000 units/mg protein). We found that a new, high-performance ion exchanger, TSK-GEL DEAE-5PW, improves this step and makes possible the large-scale preparation of pure protein. Optimal conditions for a TSK-GEL DEAE-5PW preparative column (150 × 21.5 mm I.D.) were established. The acetone-precipitated crude enzyme was dissolved in 20 m M Tris—HCl buffer (pH 7.5), protein concentration 11.0 mg/ml, applied to the column, and eluted with a linear gradient of sodium chloride from 0 to 0.3 M. The flow-rate and sample volume were set to 4.0 ml/min and 8.0 ml, respectively. Under these conditions, the fractionated Cu,Zn-superoxide dismutase showed a single band on sodium dodecyl sulfate—polyacrylamide gel electrophoresis and ion exchange high-performance liquid chromatography, and a specific activity of 3800 units/mg protein. The recovery of activity was 75%, and the cycle time was 120 min. A yield of 80–85 mg of purified enzyme was obtained per cycle. The preparation thus isolated has the highest purity and activity so far reported. We conclude that TSK-GEL DEAE-5PW is the practical choice for large-scale purification of Cu,Zn-superoxide dismutase.