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Postepy Biochemii Jun 2020The light phase of photosynthesis is a key energy process in higher plants. Its purpose is to convert light energy into chemical one stored in ATP and NADPH molecules,... (Review)
Review
The light phase of photosynthesis is a key energy process in higher plants. Its purpose is to convert light energy into chemical one stored in ATP and NADPH molecules, which are then used to assimilate CO2 and in numerous metabolic processes. Maintaining optimal photosynthesis performance requires strict regulation of thylakoid membranes organization and rapid response to changing environmental conditions. The main factor affecting photosynthesis is light, which, if applied in excessive amounts, leads to a slowdown in the process. Therefore, plants have developed many protective mechanisms regulating the light reactions of photosynthesis and operating at the level of light energy absorption, electron transport, and the distribution and use of reducing power. These include, among others: (i) non-photochemical energy quenching regulating the amount of excitation energy delivered to the photosystems; (ii) ‘state transition’ process redistributing excitation energy between photosystems; (iii) redundant electron transport pathways responsible for maintaining redox balance in chloroplasts. All these mechanisms, in combination with antioxidant systems, are designed to maintain the function of the photosynthetic apparatus in adverse growth conditions.
Topics: Chloroplasts; Electron Transport; Oxidation-Reduction; Photosynthesis; Plants
PubMed: 32700507
DOI: 10.18388/pb.2020_325 -
Chemical Reviews Jan 2022Radical aryl migrations are powerful techniques to forge new bonds in aromatic compounds. The growing popularity of photoredox catalysis has led to an influx of novel... (Review)
Review
Radical aryl migrations are powerful techniques to forge new bonds in aromatic compounds. The growing popularity of photoredox catalysis has led to an influx of novel strategies to initiate and control aryl migration starting from widely available radical precursors. This review encapsulates progress in radical aryl migration enabled by photochemical methods─particularly photoredox catalysis─since 2015. Special attention is paid to descriptions of scope, mechanism, and synthetic applications of each method.
Topics: Catalysis; Electron Transport; Electrons; Oxidation-Reduction
PubMed: 34672526
DOI: 10.1021/acs.chemrev.1c00388 -
Journal of the American College of... Jan 2012
Topics: Atorvastatin; Cardiac Surgical Procedures; Female; Heptanoic Acids; Humans; Hydroxymethylglutaryl-CoA Reductase Inhibitors; Male; Oxidation-Reduction; Pyrroles
PubMed: 22192671
DOI: 10.1016/j.jacc.2011.08.063 -
Zhejiang Da Xue Xue Bao. Yi Xue Ban =... Jan 2018: To investigate the effect of chlorogenic acid (CGA) on non-enzymatic glycation and oxidation of low density lipoprotein (LDL).
OBJECTIVE
: To investigate the effect of chlorogenic acid (CGA) on non-enzymatic glycation and oxidation of low density lipoprotein (LDL).
METHODS
: The non-enzymatic glycation incubation system of LDL-glucose was established. The contents of early glycation products (Amodori product) and intermediate products (dicarbonyl compound) were determined by ultraviolet-visible spectrophotometry, and the content of advanced glycation end products (AGEs) was determined by fluorescence spectrophotometry. The LDL oxidation incubation system was established. The contents of thiobarbituric acid reactive substances(TBARS) and conjugated diene were determined by ultraviolet-visible spectrophotometry. The tryptophan fluorescence quenching, and the content of lipofuscin, total fluorescence products, active aldehydes and malondialdehyde were determined by fluorescence spectrophotometry, and further verified by three-dimensional fluorescence spectroscopy.
RESULTS
: In the LDL glycation experiment, 150 μg/mL and 300 μg/mL CGA inhibited the formation of Amadori product, dicarbonyl compounds and AGEs. In the LDL oxidation experiment, 15 μg/mL and 25 μg/mL CGA inhibited the formation of TBARS effectively; 5 μg/mL and 10 μg/mL CGA inhibited tryptophan fluorescence quenching, and the formation of active aldehydes, malondialdehyde, total fluorescence products, lipofuscin and conjugated diolefine. And the three-dimensional fluorescence spectroscopy showed the same results.
CONCLUSIONS
: CGA can inhibit non-enzymatic glycation and oxidation of LDL.
Topics: Chlorogenic Acid; Glycosylation; Lipoproteins, LDL; Oxidation-Reduction; Thiobarbituric Acid Reactive Substances
PubMed: 30146808
DOI: 10.3785/j.issn.1008-9292.2018.02.04 -
Redox Report : Communications in Free... Dec 2018Oxidation-reduction potential (ORP) measurement can demonstrate the extent of oxidative stress in patients with severe illness and/or injury. A novel ORP diagnostic...
OBJECTIVES
Oxidation-reduction potential (ORP) measurement can demonstrate the extent of oxidative stress in patients with severe illness and/or injury. A novel ORP diagnostic platform using disposable sensors (RedoxSYS) has been validated by comparison to mass spectrometry, but the optimal methods of sample handling for best performance of the device have not been described.
METHODS
We sought to optimize ORP measurement in human plasma under controlled conditions. We hypothesized that the anticoagulant, freeze-thawing, and storage duration would influence measured ORP levels.
RESULTS
The platform was sensitive to exogenous oxidation with hydrogen peroxide and reduction with ascorbic acid. Plasma anticoagulated with heparin was more sensitive to differences in ORP than plasma prepared in citrate. ORP measurements decreased slightly after a freeze-thaw cycle, but once frozen, ORP was stable for up to one month.
DISCUSSION
We confirm that ORP detects oxidative stress in plasma samples. Optimal measurement of plasma ORP requires blood collection in heparin anticoagulant tubes and immediate analysis without a freeze-thaw cycle.
Topics: Anticoagulants; Ascorbic Acid; Heparin; Humans; Hydrogen Peroxide; Mass Spectrometry; Oxidation-Reduction; Oxidative Stress; Reactive Oxygen Species
PubMed: 29606080
DOI: 10.1080/13510002.2018.1456000 -
The Journal of Biological Chemistry May 2001
Review
Topics: Catalysis; Electron Transport; Kinetics; Nitric Oxide Synthase; Oxidation-Reduction; Oxygen
PubMed: 11279231
DOI: 10.1074/jbc.R100011200 -
Clinical Cardiology Apr 2003During myocardial ischemia, fatty acids are the principal source of energy, increasing myocardial oxygen consumption and making a decrease in coronary blood flow less...
During myocardial ischemia, fatty acids are the principal source of energy, increasing myocardial oxygen consumption and making a decrease in coronary blood flow less well tolerated. Increasing glucose oxidation during myocardial ischemia may improve cardiac efficiency. The pFOX inhibitors have the potential to accomplish this. In 2003, I think we can look forward to learning more about this class of compounds called pFOX inhibitors. Perhaps they will provide us alternative therapies in our patients who have persistent chronic stable angina pectoris despite aggressive medical therapy and/or revascularization. It seems to methat this is an increasing problem, and it is particularly common in older patients who want to remain active, but whose chronic stable angina interferes with that lifestyle.
Topics: Acetanilides; Angina Pectoris; Energy Metabolism; Enzyme Inhibitors; Fatty Acids; Humans; Myocardial Contraction; Oxidation-Reduction; Piperazines; Ranolazine
PubMed: 12708620
DOI: 10.1002/clc.4960260402 -
Journal of the American Chemical Society May 2010The oxidation of 2-deoxyribose in DNA has emerged as a critical determinant of the cellular toxicity of oxidative damage to DNA, with oxidation of each carbon producing...
Quantification of the 2-deoxyribonolactone and nucleoside 5'-aldehyde products of 2-deoxyribose oxidation in DNA and cells by isotope-dilution gas chromatography mass spectrometry: differential effects of gamma-radiation and Fe2+-EDTA.
The oxidation of 2-deoxyribose in DNA has emerged as a critical determinant of the cellular toxicity of oxidative damage to DNA, with oxidation of each carbon producing a unique spectrum of electrophilic products. We have developed and validated an isotope-dilution gas chromatography-coupled mass spectrometry (GC-MS) method for the rigorous quantification of two major 2-deoxyribose oxidation products: the 2-deoxyribonolactone abasic site of 1'-oxidation and the nucleoside 5'-aldehyde of 5'-oxidation chemistry. The method entails elimination of these products as 5-methylene-2(5H)-furanone (5MF) and furfural, respectively, followed by derivatization with pentafluorophenylhydrazine (PFPH), addition of isotopically labeled PFPH derivatives as internal standards, extraction of the derivatives, and quantification by GC-MS analysis. The precision and accuracy of the method were validated with oligodeoxynucleotides containing the 2-deoxyribonolactone and nucleoside 5'-aldehyde lesions. Further, the well-defined 2-deoxyribose oxidation chemistry of the enediyne antibiotics, neocarzinostatin and calicheamicin gamma(1)(I), was exploited in control studies, with neocarzinostatin producing 10 2-deoxyribonolactone and 300 nucleoside 5'-aldehyde per 10(6) nt per microM in accord with its established minor 1'- and major 5'-oxidation chemistry. Calicheamicin unexpectedly caused 1'-oxidation at a low level of 10 2-deoxyribonolactone per 10(6) nt per microM in addition to the expected predominance of 5'-oxidation at 560 nucleoside 5'-aldehyde per 10(6) nt per microM. The two hydroxyl radical-mediated DNA oxidants, gamma-radiation and Fe(2+)-EDTA, produced nucleoside 5'-aldehyde at a frequency of 57 per 10(6) nt per Gy (G-value 74 nmol/J) and 3.5 per 10(6) nt per microM, respectively, which amounted to 40% and 35%, respectively, of total 2-deoxyribose oxidation as measured by a plasmid nicking assay. However, gamma-radiation and Fe(2+)-EDTA produced different proportions of 2-deoxyribonolactone at 7% and 24% of total 2-deoxyribose oxidation, respectively, with frequencies of 10 lesions per 10(6) nt per Gy (G-value, 13 nmol/J) and 2.4 lesions per 10(6) nt per microM. Studies in TK6 human lymphoblastoid cells, in which the analytical data were corrected for losses sustained during DNA isolation, revealed background levels of 2-deoxyribonolactone and nucleoside 5'-aldehyde of 9.7 and 73 lesions per 10(6) nt, respectively. Gamma-irradiation of the cells caused increases of 0.045 and 0.22 lesions per 10(6) nt per Gy, respectively, which represents a approximately 250-fold quenching effect of the cellular environment similar to that observed in previous studies. The proportions of the various 2-deoxyribose oxidation products generated by gamma-radiation are similar for purified DNA and cells. These results are consistent with solvent exposure as a major determinant of hydroxyl radical reactivity with 2-deoxyribose in DNA, but the large differences between gamma-radiation and Fe(2+)-EDTA suggest that factors other than hydroxyl radical reactivity govern DNA oxidation chemistry.
Topics: Aldehydes; Cell Line, Tumor; DNA; DNA Damage; Deoxyribose; Edetic Acid; Ferrous Compounds; Gamma Rays; Gas Chromatography-Mass Spectrometry; Humans; Nucleosides; Oxidation-Reduction; Sugar Acids
PubMed: 20377226
DOI: 10.1021/ja910928n -
Molecules (Basel, Switzerland) Mar 2021This study aimed to investigate the effectiveness of 2,4,4'-trihydroxychalcone as a natural antioxidant on the oxidation of sunflower oil during an 88-day storage period...
This study aimed to investigate the effectiveness of 2,4,4'-trihydroxychalcone as a natural antioxidant on the oxidation of sunflower oil during an 88-day storage period and to compare its strength with the synthetic antioxidant butylated hydroxytoluene (BHT). Seven groups of the sunflower oil samples were prepared: pure oil (control), oil treated with different concentrations (100, 500, and 1000 ppm) of 2,4,4'-trihydroxychalcone, and oil treated with different concentrations (100, 500, and 1000 ppm) of BHT. Specific parameters, namely, the peroxide value (PV), acid value (AV), p-anisidine value (p-AnV), thiobarbituric acid reactive substance (TBARS) value and total oxidation (TOTOX) value were used to assess the extent of the deterioration of the oil by estimating the primary and secondary oxidation products. The results showed that 2,4,4'-trihydroxychalcone effectively decreased the production of the primary and secondary oxidation products of sunflower oil during storage, as indicated by reductions in the PVs, AVs, p-AnVs, TBARS values and TOTOX values of the sunflower oil. When compared to BHT, 2,4,4'-trihydroxychalcone showed either a similar or stronger effect in inhibiting the primary and secondary oxidation products. These findings suggest that, 2,4,4'-trihydroxychalcone is a suitable natural alternative to synthetic antioxidants to improve the oxidative stability of sunflower oil.
Topics: Antioxidants; Biological Products; Butylated Hydroxytoluene; Food Storage; Oxidation-Reduction; Sunflower Oil
PubMed: 33804119
DOI: 10.3390/molecules26061630 -
Chimia Oct 2021Thomas Bally has acquired international recognition for his work on the photochemistry of reactive intermediates, which include radical ions. Here, we present a brief...
Thomas Bally has acquired international recognition for his work on the photochemistry of reactive intermediates, which include radical ions. Here, we present a brief overview of our investigations of the excited-state dynamics of radical ions in liquids at room temperature, which are still poorly documented. A better understanding of these dynamics is most relevant, as open-shell ions in the excited state are being increasingly used in redox photochemistry and have been proposed to play a key role in highly exergonic photoinduced electron transfer reactions.
Topics: Electron Transport; Electrons; Ions; Oxidation-Reduction; Photochemistry
PubMed: 34728012
DOI: 10.2533/chimia.2021.856