anion radical
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2022 ◽  
Vol 12 ◽  
Author(s):  
Ruining Zhang ◽  
Zhouyu Yuan ◽  
Yuwei Jiang ◽  
Fan Jiang ◽  
Ping Chen

Surface browning after harvest is the primary constraint affecting the storage life and market circulation of rambutans. In this study, rambutan fruits were soaked in sodium nitroprusside at different concentrations and stored at 25°C for 8 days to explore the effects on postharvest quality and browning. The weight loss, browning index and superoxide anion radical, hydrogen peroxide and malondialdehyde contents of the treated fruits were reduced compared to those of the control fruits (soaked in distilled water). And fruits treated with sodium nitroprusside had a higher total phenolic content and lower polyphenol oxidase and peroxidase activity. In addition, compared with the control, the treated fruits exhibited higher phenylalanine ammonia lyase, ascorbate peroxidase and superoxide dismutase activities; titratable acidity; and soluble solid, vitamin C and protein contents, indicating high fruit quality. Overall, sodium nitroprusside treatment at 200 μmol L−1 demonstrated the most positive preservation effects. Therefore, sodium nitroprusside treatment, particularly at 200 μmol L−1, can be used as an eco-friendly, safe and convenient method for postharvest quality management and high-efficiency preservation of rambutan fruits.


Author(s):  
Siuli Das ◽  
Rakesh Mondal ◽  
Amit Kumar Guin ◽  
Nanda D Paul
Keyword(s):  

Herein, we report ligand-centered redox controlled Zn(II)-catalyzed multicomponent approaches for synthesizing pyrimidines and triazines. Taking advantage of the ligand-centered redox events, using a well-defined Zn(II)-catalyst (1a) bearing (E)-2-((4-chlorophenyl)diazenyl)-1,10-phenanthroline (L1a) as...


Author(s):  
D. V. Belov ◽  
S. N. Belyaev ◽  
M. V. Maksimov ◽  
G. A. Gevorgyan

This paper presents an experimental study of biocorrosion of D16T and AMg6 aluminum alloys. The determining role of reactive oxygen species in aluminum biocorrosion by a consortium of molds has been shown. A model is proposed, according to which the initiators of corrosion damage to the metal surface are superoxide anion radical and hydrogen peroxide released during the life of micromycetes. It is assumed that the initiation and development of biocorrosion occurs, among other things, as a result of the process of reductive activation of oxygen and the Fenton decomposition of hydrogen peroxide. A conclusion is made about the mechanism of the occurrence of intergranular and pitting corrosion of aluminum alloys interacting with microscopic fungi.


Author(s):  
Bolesław Barszcz ◽  
Tetiana N. Starodub ◽  
Adam Mizera ◽  
Roman Świetlik ◽  
Karol Rytel ◽  
...  

Author(s):  
Yu.D. Frenkel ◽  
V.S. Cherno ◽  
V.O. Kostenko

This aim of the experiment performed on 21 white rats is to clear up the effect of the nuclear factor kappa B (NF-kappa B) inhibitor on the production of reactive oxygen and nitrogen species in the liver of animals kept on carbohydrate-lipid diet and exposed to round-the-clock lighting. The study has demonstrated the administration of ammonium pyrrolidine diothiocarbamate (76 mg/kg three times a week, starting on the 30th day of the experiment) under the conditions of high-calorie carbohydrate-lipid diet (60 days) and exposure of the test animals to round-the-clock light (1500 lux for the last 30 days of the experiment) reduces the production of superoxide anion radical in the liver tissues by NADPH- and NADH-dependent electron transport chains by 45.2% and 43.5%. The production of this radical by leukocytes by NADPH oxidase was 41.6% lower than in the comparison group. The activity of NO-synthase (total and its inducible isoenzyme) decreased by 34.4 and 29.8%, the activity of the constitutive isoform increased threefold. The coupling index of the latter elevated by 5.16 times that indicates the restoration of the coupling state of this isoenzyme. The decrease in the generation of superoxide anion radical and nitric oxide was accompanied by lowering in the peroxynitrites concentration by 36.4%. We can conclude that the administration of ammonium pyrrolidine dithiocarbamate, an NF-kappa B inhibitor, during the metabolic syndrome simulated in rats by round-the-clock lightening exposure and diet rich in carbohydrates and fats is an effective means to restrict the production of reactive oxygen species.


Author(s):  
Andrey Mendkovich ◽  
Yuriy Kozyrev ◽  
Vladimir Kokorekin ◽  
Victor Luzhkov ◽  
Alexander Rusakov

Abstract The mechanism of the electrochemical oxidation of thiocyanate anion in acetonitrile was studied by cyclic voltammetry, chronoamperometry, electrolysis, digital simulations and quantum chemical calculations. The experimental data indicated the complex character of the reaction mechanism, which includes reactions of thiocyanate anion with the products of its oxidation, thiocyanate radical and thiocyanogen. It was proposed that the last reaction takes place in the reduction of thiocyanogen as well. The DFT PCM-SMD M06–2X/aug-cc-pVQZ calculations show that the reaction of thiocyanate anion with thiocyanate radical • and disproportionation of thiocyanogen anion radical are thermodynamically favorable. The effects of the mentioned reactions on the shape of the curves of cyclic voltammetry and chronoamperometry as well as that of the mass transfer regime are discussed.


2021 ◽  
Vol 12 (4) ◽  
pp. 710-717
Author(s):  
O. L. Baik ◽  
N. Y. Kyyak ◽  
O. M. Humeniuk ◽  
V. V. Humeniuk

Mosses are pioneer plants in post-technogenic areas. Therefore, the question of adaptive reactions of mosses from these habitats represents a scientific interest. The research is devoted to the study of adaptive changes in the metabolism of the dominant moss species Bryum caespiticium Hedw., collected in the devastated territories of the Novoyavorivsk State Mining and Chemical Enterprise (SMCE) “Sirka (Sulfur)” exposed to hyperthermia and insolation, which cause oxidative stress in plants. The influence of these stressors on the activity and thermal stability of antioxidant enzymes, hydrogen peroxide content, anion radical generation and accumulation of prooxidant components in moss shoots was studied. The activity and thermal stability of peroxidase and superoxide dismutase (SOD) were analysed forB. caespiticium moss from different locations of northern exposure at the sulfur mining dump No 1 in summer and autumn. We established the dependence of the activity of antioxidant enzymes of moss on the intensity of light and temperature on the experimental plots of the dump No 1. In summer, the highest activity and thermal stability rates of peroxidase and SOD were observed. Under the conditions of the experiment in shoots of В. caespiticium from the northern peak of the dump under the influence of 2 hours temperature action (+ 42 ºС) the most significant increase in peroxidase activity was found by 1.78 times and SOD by 1.89 times, as well as increase in its thermal stability by 1.35–1.42 times, respectively. The increase in peroxidase and SOD activity, as well as the increase in their thermal stability caused by hyperthermia were negated by pre-processing with a protein biosynthesis inhibitor cyclohexamide, which may indicate the participation of the protein-synthesizing system in this process. The effect of increasing the thermal stability of enzymes can be considered as a mechanism of adaptation of the protein-synthesizing system to the action of high temperatures. Increase in the activity and thermal stability of antioxidant enzymes is caused primarily by changes in the expression of stress protein genes, which control the synthesis of specific adaptogens and protectors. The obtained results indicate that the extreme conditions of the anthropogenically transformed environment contribute to the development of forms with the highest potential abilities. The mechanism of action of high temperatures is associated with the development of oxidative stress, which is manifested in the intensification of lipid peroxidation and the generation of superoxide anion radical. It was found that temperature stress and high insolation caused an increased generation of superoxide anion radical as the main inducers of protective reactions in the samples of B. caespiticium from the experimental transect of the sulfur mining heap. It is known that the synthesis of Н2О2 occurs under stress and is a signal to start a number of molecular, biochemical and physiological processes of cells, including adaptation of plants to extreme temperatures. It is shown that high temperatures initiate the generation of hydrogen peroxide. Increased reactive oxygen species (ROS) formation, including Н2О2, under the action of extreme temperatures, can cause the activation of signaling systems. Therefore, the increase in the content of Н2О2 as a signaling mediator is a component of the antioxidant protection system. It is determined that adaptive restructuring of the metabolism of the moss В. caespiticium is associated with the accumulation of signaling prooxidant components (diene and triene conjugates and dienketones). The increase in primary lipid peroxidation products, detected by us, under the action of hyperthermia may indicate the intensification of free radical oxidation under adverse climatic conditions in the area of the sulfur production dump, which leads to the intensification of lipid peroxidation processes. The accumulation of radical and molecular lipid peroxidation products are signals for the activation of protective systems, activators of gene expression and processes that lead to increased resistance of plants.


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