Possible Involvement of NADPH Oxidase in Lanthanide Cation-Induced Superoxide Anion Generation in BY-2 Tobacco Cell Suspension Culture

A rapid and concentration-dependent generation of superoxide anion （·O2^-）, measured with a superoxide-specific Cypridina luciferin-derived chemiluminescent reagent, was observed when two lanthanide salts （LaCl3 and CdCl3 ） were added to tobacco （ Nicotiana tabacum） cell suspension culture. Addition of superoxide dismutase （480 U·ml^-1） and Tiron （5 μmol·L^-1） to cell culture suspension decreases the level of lanthanide cation-induced ·O2^- generation, suggesting that ·O2^- generation is extra-cellular. Pretreatment of the cell culture suspension with diphenyleneiodonium （10 and 50 μmol·L^-1 ）, quinacrine （ 1 and 5 mmol· L^-1 ） and imidazol （ 10 mmol· L^-1 ）, inhibitors of NADPH oxidase, notably inhibits the generation of superoxide induced by lanthanide cation, implying the possible involvement of activation of NADPH oxidase. In addition, addition of SHAM （1 and 5 mmol· L^-1）, azide （0.2 and 1 mmol· L^-1 ）, inhibitor of peroxidase, has no influence on ·O2^- generation.

Superoxide Anion Radical Scavenging Ability of Quaternary Ammonium Salt of Chitosan

A series of N-alkyl or N-aryl chitosan quaternary ammonium salt were prepared using 96% deacetylated chitosan. Their scavenging activities against superoxide anion radical were investigated by chemiluminescence. The IC50 values of these compounds range from 280 to 880 μg/mL, which should be attributed to their different substitutes.

Study on Inhibition Effects of Rare Earths on Superoxide Anion Radical by Using Pulse Radiolysis

The inhibition effect of rare earths on the production of ·O - 2 produced by radiolysis of aqueous sodium formate saturated with O 2 with high energy pulse electron beam was studied. The result indicates that rare earth nitrate obviously inhibits the production of ·O - 2 . The inhibition rate is between 28 6% and 92%. The inhibition effect increases with the increase of rare earth nitrates concentration. The distinguish dose effect relationship was observed.

A High Sensitivity Detection Method of Singlet Oxygen and Superoxide Anion

This paper, for the first time, reports a method that can be used as a highly sensitive probe for singlet oxygen (1O2) and superoxide anion (O2-) in vitro or in vivo. FCLA(3,7-dihydro-6-{4-[2-(N'-(5-fluoresceinyl)thioureido)ethoxy]phenyl}-2-methylimidazo{1,2-a}pyrazin-3-one sodium salt), a chemiluminescence (CL) analysis reagent, has been reported to sensitively react with 1O2 and O2- to emit photons with a spectral peak of 525nm. In this work, when human serum albumin (HSA) was added into FCLA solution to enhance the CL intensity, approximately 20 times, compared to that without HSA. The enhanced CL had the same 525 nm spectral peak, identical to that without HSA. By gradually reducing the molecular oxygen content in the solution, we find that the auto-oxidation of oxygen molecules dissolved in the solution plays an important role in the CL process. Based on these experimental evidences, we propose a novel and highly sensitive detection method of 1O2 and O2-, which may have a great potential in chemical and medical applications.

The changes of serum nitric oxide, angiotensin Ⅱ and superoxide anion in renal artery hypertension rat

Objectives To study the changes of nitric oxide, angiotensin Ⅱ and superoxide anion in renal artery hypertension pathogenesis. Methods Male Wistar rats weighing 256 -285g were divided into 5 groups randomly, 10 rats of each group. Control group: false operation was made and routine diet was given; Ligature group: left renal artery was ligatured uncompletely and routine diet was given; Ligature + Losartan group: left renal artery was ligatured uneompletely and Losartan 20mg · kg^(-1) · d^(-1) was added in the drinking water; Ligature + L -Arg group: left renal artery was ligatured uncompletely and L -Arg 2g · kg^(-1) · d^(-1) was added in the drinking water; Ligature + L - Arg + Losartan group: left renal artery was ligatured uncompletely and L - Arg 2g· kg^(-1)· d^(-1) and Losartan 20mg · kg^(-1)· d^(-1) was added in the drinking water. Blood pressure and heart rate were measured before and at the end of the experiment. One week after ligature, blood was drawn to determine angiotensin Ⅱ, cGMP, nitric oxide, nitric oxide synthase (NOS), O_2^-, superoxide dismutase (SOD). Results Systolic blood pressure was higher in ligature group than that in control group (p <0.05), systolic blood pressure was much lower in ligature + Losartan group than that in ligature group. Heart rate did not change significantly after experiment (p > 0. 05). AngⅡ was higher in ligature group than that in control group, even much higher in ligature + Losartan group (p < 0. 01 ). There was no difference of cGMP in each group (p >. 05). The concentration of NO was lower in ligature group (p <0.05), NO was higher in ligature + L - Arg + Losartan group than that in ligature group (p <0.05). O_2^- was higher in ligature group and ligature + L - Arg group than that in control group (p < 0. 05), O_2^- was lower in ligature + Losartan group than that in ligature group (p <0. 05). The level of SOD was lower in ligature group than that in control group (p <0.05), higher in ligature + L- Arg group and ligature + L - Arg + Losartan group than that in ligature group (p <0. 05). Conclusions AngⅡ,O_2^- and NO imbalance play an important role in hypertension pathogenesis, LArg and losartan may have protective effect.

THE DISMUTATION OF SUPEROXIDE ANION BY COPPER(Ⅱ)COMPLEX OF 1,4,7,10-TETRAAZACYCLOTRIDECANE-11,13-DIONE—A KINETIC STUDY BY MEANS OF PULSE RADIOLYSIS

The dismutation kinetics of superoxide anion by copper complex of 1,4,7,10-tetranza- cyctotridecane-11,13-dione was studied by pulse radiolysis.The dismutation rate constants at various pH and concentration of complex were obtained.

The Protective Effects of N-Acetylcysteine on Exogenous Hydrogen Peroxide and Endogenous Superoxide Anion-induced DNA Strand Breakage in Human Spermatozoa

Objective To explore the protective effects of N Acetylcysteine (NAC) on exogenous hydrogen peroxide and endogenous superoxide anion induced DNA strand breakage in human spermatozoa by using the single cell gel electropherosis (SCGE) Methods Sperm cells were exposed to 0.5 mmol/L of H 2O 2 or 5.0 mmol/L of β NADPH with or without 0.1, 0.5, 1.0 mmol/L of NAC. The percentage of sperm comet cells and the comet tail lengths were measured in the treated sperm cells by using SCGE. Results Both percentage of comet sperm nuclei and mean tail length in sperm cells exposed to 0.5 mmol/L hydrogen peroxide with different concentrations of NAC decrease significantly in a dose dependent manner as compared with sperm cells exposed to H 2O 2 without NAC or catalase. Although mean tail length in sperm cells exposed to 5.0 mmol/L of β NADPH with different concentrations of NAC decreases significantly compared with sperm cells exposed to β NADPH without NAC or SOD, there were no significant differences on the percentage of sperm comet cells between sperm cells exposed to 5.0 mmol/L of β NADPH with different concentrations of NAC and sperm cells exposed to 5.0 mmol/L of β NADPH without NAC. Conclusion NAC has a protective effect on exogenous hydrogen peroxide induced DNA damage, while protective effect of NAC against O - 2 induced DNA strand breakage is significant but very weak.

Investigation on Electrochemical Behavior and Scavenging Superoxide Anion Ability of Chrysin at Mercury Electrode

The electrochemical behavior of chrysin in pH 2.0-9.0 Britton-Robinson （B-R） buffer solutions was studied by the means of linear sweep voltammetry and cyclic voltammetry at a static mercury drop electrode. In different pH range of B-R buffer solutions, chrysin could cause four reduction waves. In pH 2.0-5.8 B-R buffer solutions, wave P1 yielded by chrysin is a one-electron reduction wave, and wave P1 caused by further reduction of the products of wave P1 in pH〈3.0 B-R buffer solution is also a one-electron reduction wave. But in 3.0〈pH〈5.8 B-R buffer solution wave P1 was overlapped by the hydrogen wave. Between pH 5.8 and 9.0, chrysin could yield two reduction waves P2 and P3- The former is an irreversible adsorptive wave of ionized chrysin involving one electron and the latter is also an irreversible adsorptive wave of reduction intermediate radical of chrysin involving one electron and one proton. And a linear relationship between ip3 and the concentration of chrysin can be established from 1.0×10^-6 to 4.0×10^-5 mol·L^-1 （r=0.9924） with the detection limit of 5×10^-7 mol·L^-1. In addition, the antioxidant ability of chrysin was investigated by linear sweep voltammetry （LSV）. The determination result of IC50 of chrysin showed that chrysin is a good antioxidant.

Electrochemical Detection of Superoxide Anion Released by Living Cells by Manganese(Ⅲ) Tetraphenyl Porphine as Superoxide Dismutase Mimic

Superoxide anion,one of the most active reactive oxygen species,is associated with the development of many diseases.So monitoring superoxide anion in living cells is of great significance for the pathological research of many diseases.In this work,a new non-enzymatic sensor tor the detection of superoxide anion(O^·-2)was developed,which was iabricated by the nanocomposites composed of manganese(Ⅲ)tetraphenyl porphine(MnTPP)as superoxide dismutase mimic and electrochemical reduced graphene oxide(ERGO)as electrode support material to modify the glassy carbon electrode(GCE).The electrochemical behavior of the fabricated electrode(MiiTPP/ERGO/GCE)was performed by electrochemical impedance spectroscopy(EIS)and cyclic voltammetry(CV),which revealed that MnTPP/ERGO/GCE possessed good catalytic ability to theelectrochemical reduction of O^·-2.The MnTPP/ERGO/GCE showed excellent electroanalysis perfonnance towards O^·-2 using the technique of diflerential pulse voltanimetry(DPV)with a linear relationship in the range of 0.2—110.0μmol/L,a sensitivity of 445 μA· L·mmol^-1·cm^- 2 and a detection limit of 0.039 μmol/L(S/N=3).The real-time monitoring of O^·-2 from MCF-7 breast cancer cells stimulated by zymosan was realized in this work,which indicates that the MnTPP/ERGO/GCE hold potential application for electrochemical quantification of superoxide anions in biological applications.

Relationships Between Superoxide Anion and Microangiopathy in Non-Insulin-Dependent Diabetes Mellitus

Concentration of supemxide anion in plasma and ecythrocytes in 21 patients with non-Insulin-dependent diabetes mellitus (NIDDM)(14 with complicating microangiopathy) and 34 normal adults was assayed by chemiluinesence. Both plasma and erythrocyte concentration of .0-2 were ekvated in NIDDM with complicating microangiopathy beyond normal range (P<0.01),whereas in NIDDM without microangiopathy,in plasma was only slightly raised and RBC(.0-2) was within normal range. The authors think that RBC (.0-2) may be used as an indicator for the detection of presence of microangiopathy in NIDDM.

L-carnitine protects C2C12 cells against mitochondrial superoxide overproduction and cell death

AIM To identify and characterize the protective effect that L-carnitine exerted against an oxidative stress in C2C12 cells.METHODS Myoblastic C2C12 cells were treated with menadione, a vitamin K analog that engenders oxidative stress, and the protective effect of L-carnitine(a nutrient involved in fatty acid metabolism and the control of the oxidative process), was assessed by monitoring various parameters related to the oxidative stress, autophagy and cell death. RESULTS Associated with its physiological function, a muscle cell metabolism is highly dependent on oxygen and may produce reactive oxygen species(ROS), especially under pathological conditions. High levels of ROS are known to induce injuries in cell structure as they interact at many levels in cell function. In C2C12 cells, a treatment with menadione induced a loss of transmembrane mitochondrial potential, an increase in mitochondrial production of ROS; it also induces autophagy and was able to provoke cell death. Pre-treatment of the cells with L-carnitine reduced ROS production, diminished autophagy and protected C2C12 cells against menadione-induced deleterious effects. CONCLUSION In conclusion, L-carnitine limits the oxidative stress in these cells and prevents cell death.

Antioxidant Activity of Pigment Extracted from Green-Wheat-Bran

The anthocyanin pigment extracted from green-wheat-bran was studied to identify its antioxidant activity.The antioxidant activities of the pigment were evaluated by anti-lipid peroxidation,total antioxidant activity （TAA）,superoxide anion radical scavenging activity （SARSA）,active oxygen scavenging activity （AOSA）,and DPPH （1,1-diphenyl-2 picrylhydrazyl free radical） radical scavenging activity.The results showed that the pigment had higher antioxidant activity and TAA,SARSA,AOSA and DPPH.scavenging activities at a certain concentration than Vc （antiscorbutic vitamin,vitamin C）,and the capacity increased with the increase of pigment concentration.Its TAA was 51.06 U mL-1,1.73 times of Vc,and SARSA 18 025.21 U mL-1,2.26% higher than Vc,and AOSA 3 776.31 U mL-1,1.24 times of Vc.As to the DPPH.scavenging activity of the pigment,there was a trend that higher concentration performed higher activity significantly improved with the company of Vc.The pigment showed significant antioxidant activities evaluated by different assays.Results will provide a better understanding on antioxidant activity of green wheat and allow the screening or breeding of green wheat varieties with higher antioxidant activity for food processing.

Determination of photochemically-generated reactive oxygen species in natural water

Reactive oxygen species （ROS） can be produced by interactions between sunlight and light-absorbing substances in natural water environment. ROS may participate in the indirect photolysis of trace organic pollutants, therefore resulting in changes in their environmental fates and ecological risks in natural water systems. Bisphenol A （BPA）, an endocrine-disrupting chemical, exits widely in natural waters. The photodegradation of BPA promoted by ROS （-OH, 1O2, HO2./O2^-）, which were produced on the excitation of ubiquitous constituents （such as nitrate ion, humic substances and Fe（Ⅲ）-oxalate complexes） in natural water under simulated solar radiation was investigated. Both molecular probe method and electron spin resonance （ESR） test were used for the characterization of the generated ROS. It was found that .OH was photochemically produced in the presence of nitrate ions, humic substances and Fe（Ⅲ）-oxalate complexes and that 102 was produced with the presence of humic substances. The steady-state concentrations of .OH was 1.27×10^-14 mol/L in a nitrate solution, and the second-order rate constant of BPA with ＂OH was 1.01×10^10 L/（mol.s）.

Selenocysteine antagonizes oxygen glucose deprivation-induced damage to hippocampal neurons

Designing and/or searching for novel antioxidants against oxygen glucose effective strategy for the treatment of human isdlemic stroke. Selenium is deprivation （OGD）-induced oxidative damage represents an an essential trace dement, which is beneficial in the chemo- prevention and chemotherapy of cerebral ischemic stroke. The underlying mechanisms for its therapeutic effects, however, are not well documented. Selenocysteine （SeC） is a selenium-containing amino acid with neuroprotective potential. Studies have shown that SeC can reduce irradiation-induced DNA apoptosis by reducing DNA damage. In this study, the in vitro protective potential and mechanism of action of SeC against OGD-induced apoptosis and neurotoxicity were evaluated in HT22 mouse hippocampal neurons. We cultured HT22 cells in a glucose-free medium containing 2 mM Na2S402, which formed an OGD environment, for 90 minutes. Findings from MTT, flow cytometry and TUNEL staining showed obvious cytotoxicity and apoptosis in HT22 cells in the OGD condition. The activation of Caspa se-7 and Caspase-9 further revealed that OGD-induced apoptosis of HT22 cells was mainly achieved by triggering a mitochondrial-medi- ated pathway. Moreover, the OGD condition also induced serious DNA damage through the accumulation of reactive oxygen species and superoxide anions. However, SeC pre-treatment for 6 hours effectively inhibited OGD-induced cytotoxicity and apoptosis in HT22 cells by inhibiting reactive oxygen species-mediated oxidative damage. Our findings provide evidence that SeC has the potential to suppress OGD-induced oxidative damage and apoptosis in hippocampal neurons.

Synthesis and Antioxidant Properties of Novel Silybin Analogues

Eight novel silybin analogues （7a-h） were synthesized and their antioxidant properties including the capability of scavenging superoxide anion free radicals and the inhibitory effect on DPPH free radicals were determined. Several synthetic compounds showed comparable antioxidative effect to that of quercetin.

Molecular cloning and functional characterization of a soybean GmG MP1 gene reveals its involvement in ascorbic acid biosynthesis and multiple abiotic stress tolerance in transgenic plants

L-Ascorbic acid （AsA） plays an important role in plants and animals. In plants, GDP-D-mannose pyrophosphorylase （GMP） is essential in the AsA biosynthetic pathway. However, little is known about the genes encoding GMP in soybean and here we report genetic and functional analysis of the GmGMP1 （Glycine max GDP-D-mannose pyrophosphorylase 1） gene in this species. GmGMP1 encoded a GDP-mannose pyrophosphorylase and exhibited higher transcript levels in the leaf than in the root, stem, flower, and seed. Transcript of this gene was ubiquitous in the vegetative and reproductive organs, and was induced by abiotic stress and light. Increasing expression of GmGMP1 in Arabidopsis and soybean through an overexpressing approach caused pronounced enhancement of AsA content, and was implicated in lowering the superoxide anion radical content and lipid peroxidation levels in Arabidopsis, and conferring tolerance to osmotic and high salt stresses during seed germination. The present study represents the first systematic determination of soybean genes encoding GDP-mannose pyrophosphorylase and provides useful evidence for the functional involvement of GmGMP1 in control of AsA content and conferring tolerance to osmotic and salt stress.

Preparation of Elemental Tellurium Nanoparticles-Sucrose Sol and Its Antioxidant Activity in Vitro

The elemental tellurium nanoparticles （TeNPs） - sucrose sol was prepared by the reaction of sodium tellurite with ascorbic acid in sucrose aqueous solution. The results indicated that TeNPs were dispersion excellent in the TeNPs - sucrose sol and the morphology of TeNPs was needle-like with about 70 nm in width and 500 nm in length. The antioxidant activity of the TeNPs - sucrose sol in vitro was estimated by pyrogallol autoxidation method, Fenton method and oxygen radical absorbance capacity （ORAC） assay. The results showed that a certain amount of TeNPs - sucrose sol could effectively scavenge superoxide anion free radical and hydroxyl free radical with scavenging rates of 73 % and 57 %, respectively. ORAC assay was used to measure the total antioxidant capacity of TeNPs - sucrose sol. The order of ORAC values was 2.25 μmol.L-1 TeNPs - 0.025 % sucrose sol 〉 0.025 % sucrose 〉 2.25 μmol.L-1 Na2TeO3 〉 1.63 μmol.L-1 ascorbic acid. The results suggested that the TeNPs - sucrose sol had the excellent antioxidant activity and TeNPs were the dominating contributors to antioxidant capacity of the TeNPs - sucrose sol.

Effects of endothelial nitric oxide synthase uncoupling on pulmonary endothelial dysfunction in rats with decompression sickness

Background: To investigate the effects of unsafe decompression on rat pulmonary endothelial function and its relevant mechanisms.Methods: Sixty male Sprague-Dawley(SD) rats were randomly divided into a control group(n=30) and a decompression sickness(DCS) group(n=30). The DCS model was established by placing the rats in the DCS group in a pressurized cabin where they were exposed to a 600 k Pa compressed air environment for 60 min, and the pressure was then reduced by 100 k Pa/min until it reached atmospheric pressure. After the surviving rats in the DCS group and the rats in the control group were anesthetized, their pulmonary arteries were stripped to test the in vitro pulmonary artery endothelium-dependent vasodilation capacity. Western blotting was used to measure the expression and dissociation of endothelial nitric oxide synthase(e NOS) in pulmonary artery tissues and all protein nitration levels in pulmonary artery tissues; reactive oxygen species(ROS) formation was measured via in vitro pulmonary artery superoxide anion probe dihydroethidium(DHE) staining.Results: After experiencing unsafe decompression, 10 of the 30 rats in the DCS group died. The pulmonary artery endothelium-dependent vasodilation capacity in the surviving rats decreased significantly(P<0.05). The difference in e NOS expression between the DCS group and the control group was statistically insignificant(P>0.05), but the ratio of e NOS monomer/dimer in the DCS group was significantly higher than that in the control group(P<0.05). All protein tyrosine nitration levels in the pulmonary artery tissues of the DCS group were significantly higher than those of the control group(P<0.05). The results of DHE staining showed that the amount of ROS formation in the pulmonary arteries of the DCS group was significantly higher than that of the control group(P<0.05).Conclusion: Unsafe decompression during a simulated submarine escape process can lead to e NOS dimer uncoupling in the pulmonary artery endothelium. The dissociated e NOS monomer cannot synthesize nitric oxide(NO) and thus affect the endothelium-dependent vasodilation capacity. The e NOS monomer can promote peroxynitrite(ONOO–) synthesis, leading to an increase in protein tyrosine nitration levels in pulmonary artery tissues and causing disorder in cell cycle regulation. The e NOS monomer can also cause an increase in the formation of ROS and thus mediate peroxidation damage.

Type I Photoreaction and Photoinduced Ferroptosis by a Ru(II)Complex to Overcome Tumor Hypoxia in Photodynamic Therapy

Photodynamic therapy(PDT)usually shows limited efficacy in solid tumors since traditional PDT is O_(2)^(-)dependent while solid tumors are inherently hypoxic.In addition,hypoxic tumor cells possess antiapoptotic pathways that resist PDT-induced apoptosis.Therefore,developing photosensitizers(PSs)that show low O_(2)^(-)dependency and can induce nonapoptotic cell death pathways is critically needed.Herein,a series of Ru(II)polypyridine complex-based PSs,RuNMe,RuH,and RuCN,were synthesized,and their applications against hypoxic tumor cells through PDT were investigated.All three complexes showthe ability to generate the superoxide anion radical(·O_(2)^(-)),which is the type I photoreaction and less O_(2)^(-)dependent.RuNMe shows the best PDT performance against MCF-7 cells and three-dimensional multicellular spheroids,due to its higher cellular uptake and more reactive oxygen species generation.More importantly,RuNMe-incubated MCF-7 cells show photoinduced ferroptosis as evidenced by glutathione peroxidase 4 downregulation and lipid peroxide accumulation.This work not only develops a novel ferroptosis-inducing Ru(II)complex with the type I PDT process but also offers an effective strategy to solve tumor hypoxia in PDT.

Formation of organic chloride in the treatment of textile dyeing sludge by Fenton system

In the oxidation treatment of textile dyeing sludge,the quantitative and transformation laws of organic chlorine are not clear enough.Thus,this study mainly evaluated the treatment of textile dyeing sludge by Fenton and Fenton-like system from the aspects of the influence of Cl^(-),the removal of polycyclic aromatic hydrocarbons (PAHs) and organic carbon,and the removal and formation mechanism of organic chlorine.The results showed that the organic halogen in sludge was mainly hydrophobic organic chlorine,and the content of adsorbable organic chlorine (AOCl) was 0.30 mg/g (dry sludge).In the Fenton system with pH=3,500 mg/L Cl-,30 mmol/L Fe^(2+)and 30 mmol/L H_(2)O_(2),the removal of phenanthrene was promoted by chlorine radicals (·Cl),and the AOCl in sludge solid phase increased to 0.55 mg/g (dry sludge) at 30 min.According to spectral analysis,it was found that ·Cl could chlorinate aromatic and aliphatic compounds (excluding PAHs) in solid phase at the same time,and eventually led to the accumulation of aromatic chlorides in solid phase.Strengthening the oxidation ability of Fenton system increased the formation of organic chlorines in liquid and solid phases.In weak acidity,the oxidation and desorption of superoxide anion promoted the removal and migration of PAHs and organic carbon in solid phase,and reduced the formation of total organic chlorine.The Fenton-like system dominated by nonhydroxyl radical could realize the mineralization of PAHs,organic carbon and organic chlorines instead of migration.This paper builds a basis for the selection of sludge conditioning methods.