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1.
Nat Commun ; 15(1): 4025, 2024 May 13.
Artigo em Inglês | MEDLINE | ID: mdl-38740804

RESUMO

Intracellular membranes composing organelles of eukaryotes include membrane proteins playing crucial roles in physiological functions. However, a comprehensive understanding of the cellular responses triggered by intracellular membrane-focused oxidative stress remains elusive. Herein, we report an amphiphilic photocatalyst localised in intracellular membranes to damage membrane proteins oxidatively, resulting in non-canonical pyroptosis. Our developed photocatalysis generates hydroxyl radicals and hydrogen peroxides via water oxidation, which is accelerated under hypoxia. Single-molecule magnetic tweezers reveal that photocatalysis-induced oxidation markedly destabilised membrane protein folding. In cell environment, label-free quantification reveals that oxidative damage occurs primarily in membrane proteins related to protein quality control, thereby aggravating mitochondrial and endoplasmic reticulum stress and inducing lytic cell death. Notably, the photocatalysis activates non-canonical inflammasome caspases, resulting in gasdermin D cleavage to its pore-forming fragment and subsequent pyroptosis. These findings suggest that the oxidation of intracellular membrane proteins triggers non-canonical pyroptosis.


Assuntos
Inflamassomos , Proteínas de Membrana , Oxirredução , Piroptose , Humanos , Inflamassomos/metabolismo , Proteínas de Membrana/metabolismo , Estresse Oxidativo , Catálise , Estresse do Retículo Endoplasmático , Peróxido de Hidrogênio/metabolismo , Proteínas de Ligação a Fosfato/metabolismo , Radical Hidroxila/metabolismo , Mitocôndrias/metabolismo , Membranas Intracelulares/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Camundongos , Animais , Processos Fotoquímicos , Dobramento de Proteína , Caspases/metabolismo , Gasderminas
2.
Biochemistry (Mosc) ; 89(Suppl 1): S112-S126, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38621747

RESUMO

The review considers the problem of hydrogen peroxide decomposition and hydroxyl radical formation in the presence of iron in vivo and in vitro. Analysis of the literature data allows us to conclude that, under physiological conditions, transport of iron, carried out with the help of carrier proteins, minimizes the possibility of appearance of free iron ions in cytoplasm of the cell. Under pathological conditions, when the process of transferring an iron ion from a donor protein to an acceptor protein can be disrupted due to modifications of the carrier proteins, iron ions can enter cytosol. However, at pH values close to neutral, which is typical for cytosol, iron ions are converted into water-insoluble hydroxides. This makes it impossible to decompose hydrogen peroxide according to the mechanism of the classical Fenton reaction. A similar situation is observed in vitro, since buffers with pH close to neutral are used to simulate free radical oxidation. At the same time, iron hydroxides are able to catalyze decomposition of hydrogen peroxide with formation of a hydroxyl radical. Decomposition of hydrogen peroxide with iron hydroxides is called Fenton-like reaction. Studying the features of Fenton-like reaction in biological systems is the subject of future research.


Assuntos
Peróxido de Hidrogênio , Radical Hidroxila , Radical Hidroxila/química , Ferro/química , Hidróxidos , Oxirredução , Proteínas de Transporte
3.
Sci Rep ; 14(1): 8413, 2024 04 10.
Artigo em Inglês | MEDLINE | ID: mdl-38600137

RESUMO

Strain-specific probiotics can present antioxidant activity and reduce damage caused by oxidation. Streptococcus alactolyticus strain FGM (S. alactolyticus strain FGM) isolated from the chicken cecum shows potential probiotic properties which have been previously demonstrated. However, the antioxidant properties of S. alactolyticus strain FGM remain unknown. In this view, cell-free supernatant (CFS), intact cells (IC) and intracellular extracts (CFE) of strain FGM and 3 strains of Lactobacillus (LAB) were prepared, and their scavenging capacities against DPPH, hydroxyl radicals and linoleic acid peroxidation inhibitory were compared in this study. The effects of strain FGM cell-free supernatant (FCFS) on NO production, activity of SOD and GSH-Px in RAW264.7 cells and LPS-induced RAW264.7 cells were analyzed. The metabolites in the supernatant were quantitated by N300 Quantitative Metabolome. It was shown that the physicochemical characteristics of CFS to scavenge DPPH, hydroxyl radicals, and linoleic acid peroxidation inhibitory were significantly stronger than that of IC and CFE in the strain FGM (P < 0.05), respectively 87.12% ± 1.62, 45.03% ± 1.27, 15.63% ± 1.34. FCFS had a promotional effect on RAW264.7 cells, and significantly elevated SOD and GSH-Px activities in RAW264.7 cells. 25 µL FCFS significantly promoted the proliferation of RAW264.7 cells induced by LPS, increased the activities of SOD and GSH-PX, and decreased the release of NO. Furthermore, among the differential metabolites of FCFS quantified by N300, 12 metabolites were significantly up-regulated, including lactic acid, indole lactic acid, linoleic acid, pyruvic acid etc., many of which are known with antioxidant properties. In conclusion, FCFS had good antioxidant properties and activity, which can be attributed to metabolites produced from strain FGM fermentation. It was further confirmed that S. alactolyticus strain FGM and its postbiotic have potential probiotic properties and bright application prospects in livestock and poultry breeding.


Assuntos
Antioxidantes , Probióticos , Streptococcus , Antioxidantes/farmacologia , Antioxidantes/metabolismo , Ácido Linoleico , Lipopolissacarídeos , Probióticos/metabolismo , Radical Hidroxila , Superóxido Dismutase , Ácido Láctico/metabolismo
4.
Zhongguo Zhong Yao Za Zhi ; 49(5): 1217-1224, 2024 Mar.
Artigo em Chinês | MEDLINE | ID: mdl-38621968

RESUMO

To investigate the quality differences between the seeds and husks of Amomum villosum and explore the rationality of using the seeds without husks, this study determined the content of protocatechuic acid, vanillic acid, epicatechin, quercitrin, volatile oil, water extract, and ethanol extract. The 2,2-diphenyl-1-picrylhydrazyl(DPPH), 2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)(ABTS), and hydroxyl radical scavenging activities were determined to evaluate the antioxidant activities of seeds and husks. The quality differences between the seeds and husks were assessed through orthogonal partial least squares-discriminant analysis(OPLS-DA) and analytic hierarchy process(AHP) combined with the entropy weight method(EWM). Significant differences(P<0.05) were observed in all 10 indicators between the seeds and husks. The levels of epicatechin, quercetin, and volatile oil were higher in the seeds, whereas those of protocatechuic acid, vanillic acid, water extract, and ethanol extract were higher in the husks. The seeds showed stronger scavenging ability against DPPH and ABTS radicals, while the husks showed a stronger scavenging effect on hydroxyl radicals. OPLS-DA significantly discriminated between the seeds and husks. Furthermore, volatile oil, water extract, DPPH radical scavenging rate, quercitrin, ABTS radical scavenging rate, hydroxyl radical scavenging rate, and vanillic acid were selected as the main differential indicators by variable importance in projection(VIP). Comprehensive scores calculated by AHP combined with EWM indicated that the seeds were superior to husks in terms of overall quality. However, there are still some dominant components and a certain antioxidant effect in the husks. Therefore, it is suggested to using Amomi Fructus with a certain amount of husks or utilizing the husks for other purposes.


Assuntos
Amomum , Benzotiazóis , Catequina , Hidroxibenzoatos , Óleos Voláteis , Ácidos Sulfônicos , Radical Hidroxila , Ácido Vanílico , Antioxidantes/química , Água , Etanol , Óleos Voláteis/química
5.
Int J Nanomedicine ; 19: 2995-3007, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38559446

RESUMO

Background: In the past decades, antimicrobial resistance (AMR) has been a major threat to global public health. Long-term, chronic otitis media is becoming more challenging to treat, thus the novel antibiotic alternative agents are much needed. Methods: ZnO@TiO2@AMP (ATZ NPs) were synthesized through a solvothermal method and subjected to comprehensive characterization. The in vitro and in vivo antibacterial effect and biocompatibility of ATZ NPs were evaluated. For the antibacterial mechanism exploration, we utilized the Electron Paramagnetic Resonance (EPR) Spectrometer to detect and analyze the hydroxyl radicals produced by ATZ NPs. Results: ATZ NPs exhibited a spherical structure of 99.85 nm, the drug-loading rate for ZnO was 20.73%, and AMP within ATZ NPs was 41.86%. Notably, the Minimum Inhibitory Concentration (MIC) value of ATZ NPs against Staphylococcus aureus (S. aureus), methicillin-resistant Staphylococcus aureus (MRSA), and Streptococcus pneumoniae (S. pneumoniae) were 10 µg/mL, and Minimum Bactericidal Concentration (MBC) value of ATZ NPs against S. aureus, and S. pneumoniae were 50 µg/mL. In comparison to the model group, the treatment of otitis media with ATZ NPs significantly reduces inflammatory exudation in the middle ear cavity, with no observable damage to the tympanic membrane. Both in vivo and in vitro toxicity tests indicating the good biocompatibility of ATZ NPs. Moreover, EPR spectroscopy results highlighted the superior ability of ATZ NPs to generate hydroxyl radicals (·OH) compared to ZnO NPs. Conclusion: ATZ NPs exhibited remarkable antibacterial properties both in vivo and in vitro. This innovative application of advanced ATZ NPs, bringing great promise for the treatment of otitis media.


Assuntos
Nanopartículas Metálicas , Staphylococcus aureus Resistente à Meticilina , Otite Média , Infecções Estafilocócicas , Óxido de Zinco , Humanos , Staphylococcus aureus , Radical Hidroxila , Óxido de Zinco/farmacologia , Óxido de Zinco/química , Antibacterianos/farmacologia , Antibacterianos/química , Otite Média/tratamento farmacológico , Testes de Sensibilidade Microbiana , Nanopartículas Metálicas/química
6.
J Am Chem Soc ; 146(17): 12087-12099, 2024 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-38647488

RESUMO

Electron transfer during solid-liquid contact electrification has been demonstrated to produce reactive oxygen species (ROS) such as hydroxyl radicals (•OH) and superoxide anion radicals (•O2-). Here, we show that such a process also occurs in liquid-liquid contact electrification. By preparing perfluorocarbon nanoemulsions to construct a perfluorocarbon-water "liquid-liquid" interface, we confirmed that electrons were transferred from water to perfluorocarbon in ultrasonication-induced high-frequency liquid-liquid contact to produce •OH and •O2-. The produced ROS could be applied to ablate tumors by triggering large-scale immunogenic cell death in tumor cells, promoting dendritic cell maturation and macrophage polarization, ultimately activating T cell-mediated antitumor immune response. Importantly, the raw material for producing •OH is water, so the tumor therapy is not limited by the endogenous substances (O2, H2O2, etc.) in the tumor microenvironment. This work provides new perspectives for elucidating the mechanism of generation of free radicals in liquid-liquid contact and provides an excellent tumor therapeutic modality.


Assuntos
Fluorocarbonos , Água , Fluorocarbonos/química , Água/química , Camundongos , Animais , Neoplasias/tratamento farmacológico , Radicais Livres/química , Humanos , Radical Hidroxila/química , Espécies Reativas de Oxigênio/metabolismo , Linhagem Celular Tumoral , Antineoplásicos/química , Antineoplásicos/farmacologia
7.
Water Res ; 256: 121609, 2024 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-38615601

RESUMO

Lingering inconsistencies in the global methane (CH4) budget and ambiguity in CH4 sources and sinks triggered efforts to identify new CH4 formation pathways in natural ecosystems. Herein, we reported a novel mechanism of light-induced generation of hydroxyl radicals (•OH) that drove the production of CH4 from aquatic dissolved organic matters (DOMs) under ambient conditions. A total of five DOM samples with different origins were applied to examine their potential in photo-methanification production under aerobic conditions, presenting a wide range of CH4 production rates from 3.57 × 10-3 to 5.90 × 10-2 nmol CH4 mg-C-1 h-1. Experiments of •OH generator and scavenger indicated that the contribution of •OH to photo-methanificaiton among different DOM samples reached about 4∼42 %. In addition, Fourier transform infrared spectroscopy and Fourier transform ion cyclotron resonance mass spectrometry showed that the carbohydrate- and lipid-like substances containing nitrogen-bonded methyl groups, methyl ester, acetyl groups, and ketones, were the potential precursors for light-induced CH4 production. Based on the experimental results and simulated calculations, the contribution of photo-methanification of aquatic DOMs to the diffusive CH4 flux across the water-air interface in a typical eutrophic shallow lake (e.g., Lake Chaohu) ranged from 0.1 % to 18.3 %. This study provides a new perspective on the pathways of CH4 formation in aquatic ecosystems and a deeper understanding on the sources and sinks of global CH4.


Assuntos
Radical Hidroxila , Metano , Radical Hidroxila/química , Metano/química , Aerobiose
8.
Environ Sci Technol ; 58(17): 7505-7515, 2024 Apr 30.
Artigo em Inglês | MEDLINE | ID: mdl-38619820

RESUMO

The reaction of peracetic acid (PAA) and Fe(II) has recently gained attention due to its utility in wastewater treatment and its role in cloud chemistry. Aerosol-cloud interactions, partly mediated by aqueous hydroxyl radical (OH) chemistry, represent one of the largest uncertainties in the climate system. Ambiguities remain regarding the sources of OH in the cloud droplets. Our research group recently proposed that the dark and light-driven reaction of Fe(II) with peracids may be a key contributor to OH formation, producing a large burst of OH when aerosol particles take up water as they grow to become cloud droplets, in which reactants are consumed within 2 min. In this work, we quantify the OH production from the reaction of Fe(II) and PAA across a range of physical and chemical conditions. We show a strong dependence of OH formation on ultraviolet (UV) wavelength, with maximum OH formation at λ = 304 ± 5 nm, and demonstrate that the OH burst phenomenon is unique to Fe(II) and peracids. Using kinetics modeling and density functional theory calculations, we suggest the reaction proceeds through the formation of an [Fe(II)-(PAA)2(H2O)2] complex, followed by the formation of a Fe(IV) complex, which can also be photoactivated to produce additional OH. Determining the characteristics of OH production from this reaction advances our knowledge of the sources of OH in cloudwater and provides a framework to optimize this reaction for OH output for wastewater treatment purposes.


Assuntos
Aerossóis , Radical Hidroxila , Ácido Peracético , Radical Hidroxila/química , Ácido Peracético/química , Luz , Cinética , Ferro/química
9.
Nanoscale ; 16(17): 8479-8494, 2024 May 02.
Artigo em Inglês | MEDLINE | ID: mdl-38590261

RESUMO

Catalytic generation of toxic hydroxyl radicals (˙OH) from hydrogen peroxide (H2O2) is an effective strategy for tumor treatment in chemodynamic therapy (CDT). However, the intrinsic features of the microenvironment in solid tumors, characterized by limited H2O2 and overexpressed glutathione (GSH), severely impede the accumulation of intracellular ˙OH, posing significant challenges. To circumvent these critical issues, in this work, a CaO2-based multifunctional nanocomposite with a surface coating of Cu2+ and L-buthionine sulfoximine (BSO) (named CaO2@Cu-BSO) is designed for enhanced CDT. Taking advantage of the weakly acidic environment of the tumor, the nanocomposite gradually disintegrates, and the exposed CaO2 nanoparticles subsequently decompose to produce H2O2, alleviating the insufficient supply of endogenous H2O2 in the tumor microenvironment (TME). Furthermore, Cu2+ detached from the surface of CaO2 is reduced by H2O2 and GSH to Cu+ and ROS. Then, Cu+ catalyzes H2O2 to generate highly cytotoxic ˙OH and Cu2+, forming a cyclic catalysis effect for effective CDT. Meanwhile, GSH is depleted by Cu2+ ions to eliminate possible ˙OH scavenging. In addition, the decomposition of CaO2 by TME releases a large amount of free Ca2+, resulting in the accumulation and overload of Ca2+ and mitochondrial damage in tumor cells, further improving CDT efficacy and accelerating tumor apoptosis. Besides, BSO, a molecular inhibitor, decreases GSH production by blocking γ-glutamyl cysteine synthetase. Together, this strategy allows for enhanced CDT efficiency via a ROS storm generation strategy in tumor therapy. The experimental results confirm and demonstrate the satisfactory tumor inhibition effect both in vitro and in vivo.


Assuntos
Cálcio , Cobre , Glutationa , Peróxido de Hidrogênio , Nanocompostos , Microambiente Tumoral , Nanocompostos/química , Nanocompostos/uso terapêutico , Peróxido de Hidrogênio/química , Peróxido de Hidrogênio/metabolismo , Glutationa/metabolismo , Glutationa/química , Animais , Humanos , Camundongos , Cálcio/metabolismo , Cálcio/química , Cobre/química , Cobre/farmacologia , Microambiente Tumoral/efeitos dos fármacos , Linhagem Celular Tumoral , Butionina Sulfoximina/farmacologia , Neoplasias/tratamento farmacológico , Neoplasias/metabolismo , Neoplasias/patologia , Espécies Reativas de Oxigênio/metabolismo , Radical Hidroxila/metabolismo , Radical Hidroxila/química , Camundongos Endogâmicos BALB C
10.
Chemosphere ; 356: 141856, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38582171

RESUMO

Mechanistic investigations of an environmentally friendly and easy-to-implement oxidation method in the remediation of contaminated anoxic waters, i.e. groundwater, through the sole use of oxygen for the oxygen-induced oxidation of pollutants were the focus of this work. This was achieved by the addition of O2 under anoxic conditions in the presence of ferrous iron which initiated the ferrous oxidation and the simultaneous formation of reactive •OH radicals. The involvement of inorganic ligands such as carbonates in the activation of oxygen as part of the oxidation of Fe2+ in water was investigated, too. The formation of •OH radicals, was confirmed in two different, indirect approaches by a fluorescence-based method involving coumarin as •OH scavenger and by the determination of the oxidation products of different aromatic VOCs. In the latter case, the oxidation products of several typical aromatic groundwater contaminants such as BTEX (benzene, toluene, ethylbenzene, xylenes), indane and ibuprofen, were determined. The influence of other ligands in the absence of bicarbonate and the effect of pH were also addressed. The possibility of activation of O2 in carbonate-rich water i.e. groundwater, may also potentially contribute to oxidation of groundwater contaminants and support other primary remediation techniques.


Assuntos
Carbonatos , Recuperação e Remediação Ambiental , Água Subterrânea , Ferro , Oxirredução , Oxigênio , Poluentes Químicos da Água , Oxigênio/química , Poluentes Químicos da Água/química , Poluentes Químicos da Água/análise , Ferro/química , Água Subterrânea/química , Recuperação e Remediação Ambiental/métodos , Carbonatos/química , Compostos Orgânicos Voláteis/química , Radical Hidroxila/química
11.
Chemosphere ; 353: 141575, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38430934

RESUMO

Bisphenol A (BPA) in seawater tends to be deposited in coastal sediments. However, its degradation under tidal oscillations has not been explored comprehensively. Hydroxyl radicals (·OH) can be generated through Fe cycling under redox oscillations, which have a strong oxidizing capacity. This study focused on the contribution of Fe-mediated production of ·OH in BPA degradation under darkness. The removal of BPA was investigated by reoxygenating six natural coastal sediments, and three redox cycles were applied to prove the sustainability of the process. The importance of low reactivity Fe(II) in the production of ·OH was investigated, specifically, Fe(II) with carbonate and Fe(II) within goethite, hematite and magnetite. The degradation efficiency of BPA during reoxygenation of sediments was 76.78-94.82%, and the contribution of ·OH ranged from 36.74% to 74.51%. The path coefficient of ·OH on BPA degradation reached 0.6985 and the indirect effect of low reactivity Fe(II) on BPA degradation by mediating ·OH production reached 0.5240 obtained via partial least squares path modeling (PLS-PM). This study emphasizes the importance of low reactivity Fe(II) in ·OH production and provides a new perspective for the role of tidal-induced ·OH on the fate of refractory organic pollutants under darkness.


Assuntos
Compostos Benzidrílicos , Fenóis , Fenóis/metabolismo , Compostos Benzidrílicos/metabolismo , Radical Hidroxila , Compostos Ferrosos , Oxirredução
12.
Sci Total Environ ; 923: 171422, 2024 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-38432365

RESUMO

Throughout the entire process of sludge treatment and disposal, it is crucial to explore stable and efficient techniques to improve sludge dewaterability, which can facilitate subsequent resource utilization and space and cost savings. Traditional Fenton oxidation has been widely researched to enhance the performance of sludge dewaterability, which was limited by the additional energy input and the instabilities of Fe2+ and H2O2. To reduce the consumption of energy and chemicals and further break the rate-limiting step of the iron cycle, a novel and feasible method that constructed microbial fuel cell powered electro-Fenton systems (MFCⓅEFs) with ferrite and biochar electrode (MgFe2O4@BC/CF) was successfully demonstrated. The MFCⓅEFs with MgFe2O4@BC/CF electrode achieved specific resistance filtration and sludge cake water content of 2.52 × 1012 m/kg and 66.54 %. Cellular structure and extracellular polymeric substances (EPS) were disrupted, releasing partially bound water and destroying hydrophilic structures to facilitate sludge flocs aggregation, which was attributed to the oxidation of hydroxyl radicals. The consistent electron supply supplied by MFCⓅEFs and catalytically active sites on the surface of the multifunctional functional group electrode was responsible for producing more hydroxyl radicals and possessing a better oxidizing ability. The study provided an innovative process for sludge dewaterability improvement with high efficiency and low energy consumption, which presented new insights into the green treatment of sludge.


Assuntos
Fontes de Energia Bioelétrica , Esgotos , Esgotos/química , Peróxido de Hidrogênio/química , Ferro/química , Água/química , Oxirredução , Radical Hidroxila , Eliminação de Resíduos Líquidos/métodos
13.
Sci Total Environ ; 923: 171543, 2024 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-38453068

RESUMO

Straw returning is widely found elevating the bioavailability of cadmium (Cd) in paddy soils with unclear biogeochemical mechanisms. Here, a series of microcosm incubation experiments were conducted and spectroscopic and microscopic analyses were employed. The results showed that returning rice straw (RS) efficiently increased amorphous Fe and low crystalline Fe (II) to promote the production of hydroxyl radicals (OH) thus Cd availability in paddy soils during drainage. On the whole, RS increased OH and extractable Cd by 0.2-1.4 and 0.1-3.3 times, respectively. While the addition of RS effectively improved the oxidation rate of structural Fe (II) mineral (i.e., FeS) to enhance soil Cd activation (up to 38.5 %) induced by the increased OH (up to 69.2 %). Additionally, the existence of CO32- significantly increased the efficiency level on OH production and Cd activation, which was attributed to the improved reactivity of Fe (II) by CO32- in paddy soils. Conclusively, this study emphasizes risks of activating soil Cd induced by RS returning-derived OH, providing a new insight into evaluating the safety of straw recycling.


Assuntos
Oryza , Poluentes do Solo , Cádmio/análise , Solo/química , Ferro/análise , Oryza/química , Radical Hidroxila , Poluentes do Solo/análise
14.
Environ Sci Technol ; 58(12): 5616-5626, 2024 Mar 26.
Artigo em Inglês | MEDLINE | ID: mdl-38471100

RESUMO

Advanced oxidation processes (AOPs), such as hydroxyl radical (HO•)- and sulfate radical (SO4•-)-mediated oxidation, are attractive technologies used in water and wastewater treatments. To evaluate the treatment efficiencies of AOPs, monitoring the primary radicals (HO• and SO4•-) as well as the secondary radicals generated from the reaction of HO•/SO4•- with water matrices is necessary. Therefore, we developed a novel chemical probe method to examine five key radicals simultaneously, including HO•, SO4•-, Cl•, Cl2•-, and CO3•-. Five probes, including nitrobenzene, para-chlorobenzoic acid, benzoic acid, 2,4,6-trimethylbenzoic acid, and 2,4,6-trimethylphenol, were selected in this study. Their bimolecular reaction rate constants with diverse radicals were first calibrated under the same conditions to minimize systematic errors. Three typical AOPs (UV/H2O2, UV/S2O82-, and UV/HSO5-) were tested to obtain the radical steady-state concentrations. The effects of dissolved organic matter, Br-, and the probe concentration were inspected. Our results suggest that the five-probe method can accurately measure radicals in the HO•- and SO4•--mediated AOPs when the concentration of Br- and DOM are less than 4.0 µM and 15 mgC L-1, respectively. Overall, the five-probe method is a practical and easily accessible method to determine multiple radicals simultaneously.


Assuntos
Sulfatos , Poluentes Químicos da Água , Purificação da Água , Radical Hidroxila/química , Peróxido de Hidrogênio/química , Poluentes Químicos da Água/análise , Raios Ultravioleta , Oxirredução , Purificação da Água/métodos , Água , Cinética
15.
J Environ Sci (China) ; 142: 259-268, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38527891

RESUMO

The environmental behavior of and risks associated with nanoplastics (NPs) have attracted considerable attention. However, compared to pristine NPs, environmental factors such as ultraviolet (UV) irradiation that lead to changes in the toxicity of NPs have rarely been studied. We evaluated the changes in morphology and physicochemical properties of polystyrene (PS) NPs before and after UV irradiation, and compared their hepatotoxicity in mice. The results showed that UV irradiation caused particle size reduction and increased the carbonyl index (CI) and negative charge on the particle surface. UV-aged PS NPs (aPS NPs) could induce the generation of hydroxyl radicals (·OH), but also further promoted the generation of ·OH in the Fenton reaction system. Hepatic pathological damage was more severe in mice exposed to aPS NPs, accompanied by a large number of vacuoles and hepatocyte balloon-like changes and more marked perturbations in blood glucose and serum lipoprotein, alanine aminotransferase and aspartate aminotransferase levels. In addition, exposure to PS NPs and aPS NPs, especially aPS NPs, triggered oxidative stress and significantly damaged the antioxidant capacity of mice liver. Compared with PS NPs, exposure to aPS NPs increased the number of altered metabolites in hepatic and corresponding metabolic pathways, especially glutathione metabolism. Our research suggests that UV irradiation can disrupt the redox balance in organisms by promoting the production of ·OH, enhancing PS NPs-induced liver damage and metabolic disorders. This study will help us understand the health risks of NPs and to avoid underestimation of the risks of NPs in nature.


Assuntos
Nanopartículas , Poluentes Químicos da Água , Animais , Camundongos , Radical Hidroxila , Microplásticos/toxicidade , Poliestirenos/toxicidade , Raios Ultravioleta , Fígado , Nanopartículas/toxicidade
16.
Redox Biol ; 71: 103110, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38492556

RESUMO

We obviously agree with Wu et al. that H2O2 might accumulate in the Archean land waters devoid of Fe2+. We do disagree on the topic of the half-life of H2O2, as the work cited in support for a longer half-live is not relevant to the conditions in the Archean ocean. While the existence of radicals in quartz is not in doubt, we do question the hypothesis that these radicals oxidize water to HO• and H2O2.


Assuntos
Peróxido de Hidrogênio , Oxigênio , Fotossíntese , Radical Hidroxila , Oxirredução
17.
J Hazard Mater ; 470: 134118, 2024 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-38547752

RESUMO

Urine is the major source of nitrogen pollutants in domestic sewage and is a neglected source of H2. Although ClO• is used to overcome the poor selectivity and slow kinetics of urea decomposition, the generation of ClO• suffers from the inefficient formation reaction of HO• and reactive chlorine species (RCS). In this study, a synergistic catalytic method based on TiO2/WO3 photoanode and Sb-SnO2 electrode efficiently producing ClO• is proposed for urine treatment. The critical design is that TiO2/WO3 photoanode and Sb-SnO2 electrode that generate HO• and RCS, respectively, are assembled in a confined space through face-to-face (TiO2/WO3//Sb-SnO2), which effectively strengthens the direct reaction of HO• and RCS. Furthermore, a Si solar panel as rear photovoltaic cell (Si PVC) is placed behind TiO2/WO3//Sb-SnO2 to fully use sunlight and provide the driving force of charge separation. The composite photoanode (TiO2/WO3//Sb-SnO2 @Si PVC) has a ClO• generation rate of 260% compared with the back-to-bake assembly way. In addition, the electrons transfer to the NiFe LDH@Cu NWs/CF cathode for rapid H2 production by the constructed photoelectric catalytic (PEC) cell without applied external biasing potential, in which the H2 production yield reaches 84.55 µmol h-1 with 25% improvement of the urine denitrification rate. The superior performance and long-term stability of PEC cell provide an effective and promising method for denitrification and H2 generation.


Assuntos
Antimônio , Eletrodos , Óxidos , Compostos de Estanho , Titânio , Tungstênio , Titânio/química , Tungstênio/química , Compostos de Estanho/química , Catálise , Antimônio/química , Óxidos/química , Urina/química , Cloro/química , Radical Hidroxila/química
18.
Environ Sci Technol ; 58(11): 5139-5152, 2024 Mar 19.
Artigo em Inglês | MEDLINE | ID: mdl-38446791

RESUMO

Plasma has been proposed as an alternative strategy to treat organic contaminants in brines. Chemical degradation in these systems is expected to be partially driven by halogen oxidants, which have been detected in halide-containing solutions exposed to plasma. In this study, we characterized specific mechanisms involving the formation and reactions of halogen oxidants during plasma treatment. We first demonstrated that addition of halides accelerated the degradation of a probe compound known to react quickly with halogen oxidants (i.e., para-hydroxybenzoate) but did not affect the degradation of a less reactive probe compound (i.e., benzoate). This effect was attributed to the degradation of para-hydroxybenzoate by hypohalous acids, which were produced via a mechanism involving halogen radicals as intermediates. We applied this mechanistic insight to investigate the impact of constituents in brines on reactions driven by halogen oxidants during plasma treatment. Bromide, which is expected to occur alongside chloride in brines, was required to enable halogen oxidant formation, consistent with the generation of halogen radicals from the oxidation of halides by hydroxyl radical. Other constituents typically present in brines (i.e., carbonates, organic matter) slowed the degradation of organic compounds, consistent with their ability to scavenge species involved during plasma treatment.


Assuntos
Oxidantes , Sais , Poluentes Químicos da Água , Compostos Orgânicos , Radical Hidroxila/química , Oxirredução , Halogênios/química , Hidroxibenzoatos , Poluentes Químicos da Água/química
19.
Environ Sci Technol ; 58(13): 5911-5920, 2024 Apr 02.
Artigo em Inglês | MEDLINE | ID: mdl-38437592

RESUMO

HONO acts as a major OH source, playing a vital role in secondary pollutant formation to deteriorate regional air quality. Strong unknown sources of daytime HONO have been widely reported, which significantly limit our understanding of radical cycling and atmospheric oxidation capacity. Here, we identify a potential daytime HONO and OH source originating from photoexcited phenyl organic nitrates formed during the photoreaction of aromatics and NOx. Significant HONO (1.56-4.52 ppb) and OH production is observed during the photoreaction of different kinds of aromatics with NOx (18.1-242.3 ppb). We propose an additional mechanism involving photoexcited phenyl organic nitrates (RONO2) reacting with water vapor to account for the higher levels of measured HONO and OH than the model prediction. The proposed HONO formation mechanism was evidenced directly by photolysis experiments using typical RONO2 under UV irradiation conditions, during which HONO formation was enhanced by relative humidity. The 0-D box model incorporated in this mechanism accurately reproduced the evolution of HONO and aromatic. The proposed mechanism contributes 5.9-36.6% of HONO formation as the NOx concentration increased in the photoreaction of aromatics and NOx. Our study implies that photoexcited phenyl organic nitrates are an important source of atmospheric HONO and OH that contributes significantly to atmospheric oxidation capacity.


Assuntos
Poluentes Ambientais , Ácido Nitroso , Ácido Nitroso/análise , Radical Hidroxila , Oxirredução , Raios Ultravioleta , Nitratos
20.
Molecules ; 29(5)2024 Mar 02.
Artigo em Inglês | MEDLINE | ID: mdl-38474637

RESUMO

Based on the reported research, hydroxyl radicals can be rapidly transformed into carbonate radicals in the carbonate-bicarbonate buffering system in vivo. Many of the processes considered to be initiated by hydroxyl radicals may be caused by carbonate radicals, which indicates that lipid peroxidation initiated by hydroxyl radicals can also be caused by carbonate radicals. To date, theoretical research on reactions of hydrogen abstraction from and radical addition to polyunsaturated fatty acids (PUFAs) of carbonate radicals has not been carried out systematically. This paper employs (3Z,6Z)-nona-3,6-diene (NDE) as a model for polyunsaturated fatty acids (PUFAs). Density functional theory (DFT) with the CAM-B3LYP method at the 6-311+g(d,p) level was used to calculate the differences in reactivity of carbonate radicals abstracting hydrogen from different positions of NDE and their addition to the double bonds of NDE under lipid solvent conditions with a dielectric constant of 4.0 (CPCM model). Grimme's empirical dispersion correction was taken into account through the D3 scheme. The energy barrier, reaction rate constants, internal energy, enthalpy and Gibbs free energy changes in these reactions were calculated With zero-point vibrational energy (ZPVE) corrections. The results indicated that carbonate radicals initiate lipid peroxidation primarily through hydrogen abstraction from diallyl carbon atoms. The reaction of hydrogen abstraction from diallyl carbon atoms exhibits the highest reaction rate, with a reaction rate constant approximately 43-fold greater than the second-ranked hydrogen abstraction from allyl carbon atoms. This process has the lowest energy barrier, internal energy, enthalpy, and Gibbs free energy changes, indicating that it is also the most spontaneous process.


Assuntos
Ácidos Graxos Insaturados , Hidrogênio , Peroxidação de Lipídeos , Hidrogênio/química , Ácidos Graxos Insaturados/química , Carbonatos , Radical Hidroxila/química , Carbono , Radicais Livres/química
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