气孔运动中的活性氧信号

大量研究证明活性氧(ROS)在气孔运动中起信号分子的作用。保卫细胞中ROS的产生依赖于特定的酶,其中NADPH氧化酶组分RBOH已得到深入研究,并已证实其参与生物与非生物胁迫反应。植物激素包括脱落酸(ABA)、水杨酸(SA)、乙烯、生长素及细胞分裂素等,它们均通过ROS的介导来调控气孔运动。生物胁迫(如毒性细菌和真菌)也会调控气孔运动。ROS参与这些调控过程。保卫细胞中存在多层次对ROS产生及其作用的调节,抗氧化活性物质和ROS敏感蛋白(如蛋白激酶和磷酸酶)均可传递ROS信号并调节气孔运动。ROS对离子通道调节的证据也越来越多。保卫细胞由于可通过ROS整合复杂的信号途径,已成为研究植物ROS信号转导过程的良好模式系统。     

Determination of Mitochondrial Membrane Potential and Reactive Oxygen Species in Live Rat Cortical Neurons

Mitochondrial membrane potential (ΔΨm) is critical for maintaining the physiological function of the respiratory chain to generate ATP. A significant loss of ΔΨm renders cells depleted of energy with subsequent death. Reactive oxygen species (ROS) are important signaling molecules, but their accumulation in pathological conditions leads to oxidative stress. The two major sources of ROS in cells are environmental toxins and the process of oxidative phosphorylation. Mitochondrial dysfunction and oxidative stress have been implicated in the pathophysiology of many diseases; therefore, the ability to determine ΔΨm and ROS can provide important clues about the physiological status of the cell and the function of the mitochondria. Several fluorescent probes (Rhodamine 123, TMRM, TMRE, JC-1) can be used to determine Δψm in a variety of cell types, and many fluorescence indicators (Dihydroethidium, Dihydrorhodamine 123, H₂DCF-DA) can be used to determine ROS. Nearly all of the available fluorescence probes used to assess ΔΨm or ROS are single-wavelength indicators, which increase or decrease their fluorescence intensity proportional to a stimulus that increases or decreases the levels of ΔΨm or ROS. Thus, it is imperative to measure the fluorescence intensity of these probes at the baseline level and after the application of a specific stimulus. This allows one to determine the percentage of change in fluorescence intensity between the baseline level and a stimulus. This change in fluorescence intensity reflects the change in relative levels of ΔΨm or ROS. In this video, we demonstrate how to apply the fluorescence indicator, TMRM, in rat cortical neurons to determine the percentage change in TMRM fluorescence intensity between the baseline level and after applying FCCP, a mitochondrial uncoupler. The lower levels of TMRM fluorescence resulting from FCCP treatment reflect the depolarization of mitochondrial membrane potential. We also show how to apply the fluorescence probe H₂DCF-DA to assess the level of ROS in cortical neurons, first at baseline and then after application of H₂O₂. This protocol (with minor modifications) can be also used to determine changes in ∆Ψm and ROS in different cell types and in neurons isolated from other brain regions.     

菟丝子提取物对活性氧引起已分化的PC12细胞损伤的保护作用

以常用的神经嗜铬细胞瘤PC12细胞株为实验模型,通过比较活性氧(ROS)作用细胞后的细胞活力、凋亡相关蛋白(p53、Bax)水平以及细胞中SOD、GSH、MDA的差异,发现菟丝子提取物不仅能提高ROS损伤的已分化PC12细胞活力,调节细胞中凋亡相关基因的表达,而且还能提高细胞中SOD和GSH的含量,降低MDA水平。由此表明,菟丝子提取物对ROS造成的PC12细胞损伤有一定的保护作用。     

Antioxidant Combination Inhibits Reactive Oxygen Species Mediated Damage

We examined the preventive activity of naturally occurring antioxidants against three reactive oxygen species using a protein degradation assay. The hydroxyl, hypochlorite, and peroxynitrite radicals are typical reactive oxygen species generated in human body. Previously, we found that hydrophobic botanical antioxidants exhibited specific antioxidant activity against hydroxyl radicals, whereas anserine and carnosine mixture, purified from chicken extract and vitamin C, exhibited antioxidant activities against hypochlorite and peroxynitrite radicals respectively. Since ethanol, used as a solvent in the experiments, also showed an antioxidant action against the hydroxyl radical, we re-assessed antioxidant activities using aqueous solutions of botanical antioxidants. Among the seven hydrophobic antioxidants examined, ferulic acid exhibited the strongest antioxidant activity against the hydroxyl radical. An antioxidant preparation of anserine-carnosine mixture, vitamin C, and ferulic acid prevented oxidative stress by reactive oxygen species. Loss of deformability in human erythrocytes and protein degradation caused by reactive oxygen species were completely inhibited.     

Chemical Hypoxia-Induced Cell Death in Human Glioma Cells: Role of Reactive Oxygen Species,ATP Depletion,Mitochondrial Damage and Ca2+

This study was undertaken to evaluate whether chemical hypoxia-induced cell injury is a result of reactive oxygen species (ROS) generation, ATP depletion, mitochondrial permeability transition, and an increase in intracellular Ca²⁺, in A172 cells, a human glioma cell line. Chemical hypoxia was induced by incubating cells with antimycin A, an inhibitor of mitochondrial electron transport, in a glucose-free medium. Exposure of cells to chemical hypoxia resulted in cell death, ROS generation, ATP depletion, and mitochondrial permeability transition. The H₂O₂ scavenger pyruvate prevented cell death, ROS generation, and mitochondrial permeability transition induced by chemical hypoxia. In contrast, changes mediated by chemical hypoxia were not affected by hydroxyl radical scavengers. Antioxidants did not affect cell death and ATP depletion induced by chemical hypoxia, although they prevented ROS production and mitochondrial permeability transition induced by chemical hypoxia. Chemical hypoxia did not increase lipid peroxidation even when antimycin A was increased to 50 M, whereas the oxidant t-butylhydroperoxide caused a significant increase in lipid peroxidation, at a concentration that is less effective than chemical hypoxia in inducing cell death. Fructose protected against cell death and mitochondrial permeability transition induced by chemical hypoxia. However, ROS generation and ATP depletion were not prevented by fructose. Chemical hypoxia caused the early increase in intracellular Ca²⁺. The cell death and ROS generation induced by chemical hypoxia were altered by modulation of intracellular Ca²⁺ concentration with ruthenium red, TMB-8, and BAPTA/AM. However, mitochondrial permeability transition was not affected by these compounds. These results indicate that chemical hypoxia causes cell death, which may be, in part, mediated by H₂O₂ generation via a lipid peroxidation-independent mechanism and elevated intracellular Ca²⁺. In addition, these data suggest that chemical hypoxia-induced cell death is not associated directly with ATP depletion and mitochondrial permeability transition.     

Generation of Reactive Oxygen Species from Hinokitiol under Near-UV Irradiation

Near-UV irradiation caused the decomposition of hinokitiol in an aqueous solution. During the photochemical reaction, the distinct electron spin resonance signal characteristic of the adduct of 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) with the hydroxyl radical was accompanied by small signals corresponding to the adduct of DMPO with the superoxide anion radical. More than 95% of Escherichia coli cells were killed by the incubation with hinokitiol under near-UV irradiation by BLB fluorescent lamps. These results indicated the generation of reactive oxygen species during photochemical reaction of hinokitiol under near-UV irradiation.     

The Role of Reactive Oxygen Species in Mitochondrial Permeability Transition

We have provided evidence that mitochondrial membrane permeability transition induced by inorganic phosphate, uncouplers or prooxidants such as t-butyl hydroperoxide and diamide is caused by a Ca²⁺-stimulated production of reactive oxygen species (ROS) by the respiratory chain, at the level of the coenzyme Q. The ROS attack to membrane protein thiols produces cross-linkage reactions, that may open membrane pores upon Ca²⁺ binding. Studies with submitochondrial particles have demonstrated that the binding of Ca²⁺ to these particles (possibly to cardiolipin) induces lipid lateral phase separation detected by electron paramagnetic resonance experiments exploying stearic acids spin labels. This condition leads to a disorganization of respiratory chain components, favoring ROS production and consequent protein and lipid oxidation.     

钙抑制剂对机械损伤胁迫下合作杨叶片活性氧代谢的影响

以1年生合作杨扦插苗为材料,研究了叶面喷施Ca2+通道阻断剂氯化镧(LaCl3)和Ca2+螯合剂EGTA预处理对机械损伤胁迫下合作杨叶片抗氧化酶活性、过氧化氢(H2O2)和丙二醛(MDA)含量以及氧自由基(O2?-)产生速率的影响.结果显示,与对照相比,机械损伤胁迫下合作杨叶片超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)和抗坏血酸过氧化物酶(APX)等抗氧化酶活性均显著升高,活性氧水平和MDA含量显著增加;外源喷施EGTA和LaCl3降低了机械损伤胁迫下叶片SOD、POD、CAT和APX活性,减缓了O2?-产生速率,H2O2含量和MDA含量显著下降;且EGTA的抑制作用比LaCl3更强.研究表明,机械损伤胁迫诱导的活性氧代谢需要Ca2+的参与,Ca2+和活性氧在植物防御信号传递过程中密切相关;伤害诱导胞外Ca2+内流是胞内Ca2+浓度增加的重要来源.     

活性氧簇对蛋白尿的影响

蛋白尿不仅反映肾小球损伤,而且是一个独立的导致肾脏病变进展的主要因素,任何能够使蛋白尿减少的治疗干预都有利于减慢肾脏疾病的进展,遗传性蛋白尿性肾病是由于基因突变所致,获得性肾病大量蛋白尿成因目前尚未阐明。免疫异常,炎症介质及氧化应激反应均可导致肾损伤。氧自由基是肾损伤的主要介质,它作为强氧化剂是造成蛋白尿的重要原因之一。活性氧分子(ROS)可以通过降解肾小球乙酰肝素硫酸盐、肾小球基底膜Ⅳ型胶原富含赖氨酸的NCl区域发生交联、损伤足细胞破坏肾小球滤过屏障及与其他活性因子作用增强血清蛋白的渗透性等作用,造成蛋白尿。本文就近年来人们对活性氧造成蛋白尿的机制的研究做一综述,便于帮助医务工作者更好的了解和治疗蛋白尿性肾病。     

Involvement of Reactive Oxygen Species in Plant Mitochondrial Response to Low-Temperature Stress

The review presents data for the generation of the reactive oxygen species (ROS) in mitochondria during low-temperature stress. The relation of lipid peroxidation processes in membranes to the induction of low-temperature stress is demonstrated. The data for the involvement of the mitochondrial uncoupling proteins and the processes of uncoupling oxidation and phosphorylation in the regulation of mitochondrial ROS formation during low-temperature stress are considered.     

Reactive Oxygen Species and Human Inflammatory Periodontal Diseases

Reactive oxygen species (ROS) have emerged as important signaling molecules in the regulation of various cellular processes. They can be generated by the mitochondrial electron transport chain in mitochondria and activation of polymorphonuclear leukocytes (PMN) during inflammatory conditions. Excessive generation of ROS may result in attack of and damage to most intracellular and extracellular components in a living organism. Moreover, ROS can directly induce and/or regulate apoptotic and necrotic cell death. Periodontal pathologies are inflammatory and degenerative diseases. Several forms of periodontal diseases are associated with activated PMN. Damage of tissues in inflammatory periodontal pathologies can be mediated by ROS resulting from the physiological activity of PMN during the phagocytosis of periodontopathic bacteria.__________Translated from Biokhimiya, Vol. 70, No. 6, 2005, pp. 751–761.Original Russian Text Copyright © 2005 by Canakci, Cicek, Canakci.     

活性氮、活性氧及植物激素在种子休眠解除中的作用及相互关系研究进展

休眠是植物种子对环境变化的适应机制,其机理至今未完全清楚阐明。前期对种子休眠机制的研究主要集中在激素调节上,近期的研究结果表明,一氧化氮（nitric oxide,NO）参与打破种子的休眠,并与其所引起的种子中活性氧的变化有关。本文简要综述活性氮（reactive nitrogen species,RNS）、活性氧（reactive oxygen species,R0s）和植物激素在种子休眠解除中的作用及相互关系研究进展。     

Production of Reactive Oxygen Species and Release of l-Glutamate During Superoxide Anion-Induced Cell Death of Cerebellar Granule Neurons

Abstract: Enhanced production of superoxide anion (O₂⁻) is considered to play a pivotal role in the pathogenesis of CNS neurons. Here, we report that O₂⁻ generated by xanthine (XA) + xanthine oxidase (XO) triggered cell death associated with nuclear condensation and DNA fragmentation in cerebellar granule neuron. XA + XO induced significant increases in amounts of intracellular reactive oxygen species (ROS) before initiating loss of cell viability, as determined by measurement of 6-carboxy-2',7'-dichlorodihydrofluorescein diacetate, di(acetoxymethyl ester) (C-DCDHF-DA) for O₂⁻ and other ROS and hydroethidine (HEt) specifically for O₂⁻ by using fluorescence microscopy and flow cytometry. Catalase, but not superoxide dismutase (SOD), significantly protected granule neurons from the XA + XO-induced cell death. Catalase effectively reduced C-DCDHF-DA but not HEt fluorescence, whereas SOD reduced HEt but not C-DCDHF-DA fluorescence, indicating that HEt and C-DCDHF-DA fluorescence correlated with O₂⁻ and hydrogen peroxide, respectively. The NMDA antagonist MK-801 prevented the death. XA + XO induced an increase in l -glutamate release from cerebellar granule neurons. These results indicate that elevation of O₂⁻ induces cell death associated with increasing ROS production in cerebellar granule neurons and that XA + XO enhanced release of l -glutamate.     

Chitosan-Induced Stomatal Closure Accompanied by Peroxidase-Mediated Reactive Oxygen Species Production in Arabidopsis

Chitosan induced stomatal closure in wild type-plants and NADPH oxidase knock-out mutants (atrbohD atrbohF), and reactive oxygen species (ROS) production in wild-type guard cells. Closure and production were completely abolished by catalase and a peroxidase inhibitor. These results indicate that chitosan induces ROS production mediated by peroxidase, resulting in stomatal closure.     

Monoamine-dependent Production of Reactive Oxygen Species Catalyzed by Pseudoperoxidase Activity of Human Hemoglobin

Hemoglobin (Hb) solution-based blood substitutes are being developed as oxygen-carrying agents for the prevention of ischemic tissue damage and low blood volume-shock. However, the cell-free Hb molecule has intrinsic toxicity to the tissue since harmful reactive oxygen species (ROS) are readily produced during autoxidation of Hb from the ferrous state to the ferric state, and the cell-free Hb also causes distortion in the oxidant/antioxidant balance in the tissues. There may be further hindering dangers in the use of free Hb as a blood substitute. It has been reported that Hb has peroxidase-like activity oxidizing peroxidase substrates such as aromatic amines. Here we observed the Hb-catalyzed ROS production coupled to oxidation of a neurotransmitter precursor, β-phenylethylamine (PEA). Addition of PEA to Hb solution resulted in generation of superoxide anion (O₂^??). We also observed that PEA increases the Hb-catalyzed monovalent oxidation of ascorbate to ascorbate free radicals (Asc^?). The O₂^?? generation and Asc^? formation were detected by O₂^??-specific chemiluminescence of the Cypridina lucigenin analog and electron spin resonance spectroscopy, respectively. PEA-dependent O₂^?? production and monovalent oxidation of ascorbate in the Hb solution occurred without addition of H₂O₂, but a trace of H₂O₂ added to the system greatly increased the production of both O₂^?? and Asc^?. Addition of GSH completely inhibited the PEA-dependent production of O₂^?? and Asc^? in Hb solution. We propose that the O₂^?? generation and Asc^? formation in the Hb solution are due to the pseudoperoxidase activity-dependent oxidation of PEA and resultant ROS may damage tissues rich in monoamines, if the Hb-based blood substitutes were circulated without addition of ROS scavengers such as thiols.     

活性氧水平决定白血病细胞对三氧化二砷诱导凋亡的敏感性

旨在探索三氧化二砷（As2O3)诱导白血病细胞株（NB4和U937）凋亡的敏感性与细胞活性氧（reactive oxy-gen species,ROS)水平的关系。以二甲萘醌（DMNQ）温育NB4和U937细胞,双氢罗丹明123（DHR）捕获ROS,流式细胞仪检测两种细胞ROS水平的差异。As2O3单独或联用DMNQ温育NB4和U937细胞,流式细胞仪及电镜检测凋亡并分析两种细胞凋亡敏感性的差异及其在用药前后的变化。结果显示,NB4的ROS水平明显高于U937,DMNQ可提高NB4和U937的ROS水平,诱发U937对As2O3的敏感性,增强As2O3促NB4细胞凋亡的效应,过氧化氢酶可逆转DMNQ的效应,结果提示,白血病细胞NB4和U937对As2O3促凋亡的敏感性决定于细胞固有的ROS水平。     

Reactive Oxygen Species as Essential Components of Ambient Air

In this review evidence for the presence of the anion radical in atmospheric air is considered, and the biological activity of superoxide and negative air ions is compared. Various aspects of the biological effect of superoxide and other reactive oxygen species contained in air at the cell, tissue, and organism levels are discussed. The results of the therapeutic use of exogenous gaseous superoxide and low doses of H₂O₂ for the treatment of bronchial asthma, pain, and Parkinson's disease are reported. A hypothesis on the mechanism of physiological action of exogenous reactive oxygen species is discussed.     

活性氧、钙和心力衰竭

活性氧信号和钙信号广泛存在于机体内,两者相互作用,共同参与调节机体多种生理功能及病理过程。本文对这两个信号系统之间的相互作用及相关机制、在心力衰竭过程中的作用及可能的临床应用前景进行了综述。     

基于活性氧自由基水平评价蔬菜重金属污染

蔬菜细胞中活性氧自由基水平处于一定范围内,而蔬菜一旦受重金属污染,活性氧自由基水平将发生改变.本文采用2＇,7＇-二氯荧光黄双乙酸酯标记蔬菜叶片细胞内活性氧自由基,激光扫描共聚焦显微镜技术分析蔬菜受重金属污染后活性氧自由基荧光强度的变化.结果表明,不同浓度镉、铅、汞离子（0、25、50、100 mg/L）作用芹菜、菠菜和油菜后,蔬菜叶片中活性氧自由基荧光强度均呈上升趋势,基于活性氧自由基水平的升高可判断蔬菜是否受重金属污染.本研究建立了基于活性氧自由基水平的蔬菜重金属污染评价方法,进一步为蔬菜的监管提供方法学和技术理论基础.